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  • rotifers  (57)
  • Biomagnetism (including magnetocardiography)  (46)
  • Phosphorus  (26)
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  • Springer  (135)
  • Blackwell Publishing Ltd
  • 1990-1994
  • 1980-1984  (135)
  • 1925-1929
  • 1983  (135)
Collection
Keywords
Publisher
  • Springer  (135)
  • Blackwell Publishing Ltd
Years
  • 1990-1994
  • 1980-1984  (135)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Instrumentation for biomagnetism (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 123-141 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si riesamina la strumentalizzazione adatta all’acquisizione di segnali biomagnetici. Si studiano separatamente i componenti di base del magnetometro, cioè gli SQUID, i trasformatori di flusso e i dewar. Si discutono i possibili miglioramenti alla strumentazione attuale e alle apparecchiature complete comprendenti scudi ferromagnetici o di correnti a vortice e si valuta la loro efficenza.
    Notes: Summary The instrumentation suitable for the acquisition of biomagnetic signals is reviewed. The basic magnetometer components,i.e. SQUIDs, flux transformers and dewars, are studied separately. Possible improvements to the present instrumentation as well as complete set-ups including ferromagnetic or eddy current shields are discussed and their efficiency evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455917
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  • 2
    Electronic Resource
    Electronic Resource
    First-gradient balancing of higher-order gradiometers (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 142-152 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si sviluppa un formalismo per la descrizione vettoriale e tensoriale di una procedura di bilanciamento e si sottolinea un metodo di bilanciamento di campo e di primo gradiente. Si discutono l’apparecchiatura sperimentale e le misurazioni del vettore di modo comune del primo gradienteC G 1.
    Notes: Summary A formalism for the vector and tensor description of a balancing procedure is developed and a first-gradient and field-balancing method is outlined. The experimental apparatus and measurements of the first-gradient common-mode vector,C G 1, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455918
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  • 3
    Electronic Resource
    Electronic Resource
    Optimization of the second-order gradiometer base length that has been designed for the measurement of weak inhomogeneous magnetic fields (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 175-183 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si tratta il problema dell’ottimizzazione di sistemi di sensori gradiometrici metrici superconduttori di secondo ordine che sono stati progettati per la misurazione di campi magnetici deboli disomogenei in un ambiente disturbato magneticamente. Si considerano le condizioni di massimo rapporto segnale-rumore dell’uscita del quantomagnetometro superconduttote (SQM). Si analizza l’influenza dei parametri misurati della sorgente del segnale, del rumore di una sorgente di disturbo esterna e di quello proprio del magnetometro sulla selezione della lunghezza di base del gradiometro.
    Notes: Summary In this paper we deal with an optimization problem of the second-order superconducting gradiometric sensor systems that have been designed for measurement of the weak inhomogeneous magnetic fields in a magnetically disturbed environment. The conditions of maximum signalto-noise ratio of the output of superconducting quantum magnetometers (SQM) are considered. The influence of measured signal source parameters, of an outside disturbing source and of the own noise of the magnetometer on the gradiometer base length selection is analysed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455921
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  • 4
    Electronic Resource
    Electronic Resource
    Optimizing vector magnetocardiographic lead fields by using a physical torso model (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 356-367 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono state esaminate l’idealità e la sensibilità di parecchi conduttori magnetocardiografici vettoriali usando un modello inomogeneo fisico del tronco. Si è trovato che la componente antero-posterioreX vettore magnetico del cuore è la piú facile da scoprire. Si suggeriscono conduttori ideali per le altre due componenti. Comunque questi hanno una sensibilità inferiore. Le differenze rispetto ai risultati di precedenti ricercatori sono state spiegate con le differenze tra i modelli.
    Notes: Summary The ideality and sensitivity of several vector magnetocardiographic leads were tested by using an inhomogeneous, physical torso model. The postero-anterior component of the heart’s magnetic vector was found easiest to detect. New, more ideal leads for the other two components are suggested. However, these have lower sensitivity. The differences from the results of former investigators can be explained by the differences of the models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455938
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  • 5
    Electronic Resource
    Electronic Resource
    Adaptive noise cancellation in neuromagnetic measurement systems (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 203-213 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è studiato lo spettro del rumore di un gradiometro superconduttore a derivata secon da in un agglomerato urbano. I dati sono stati ottenuti dal gradiometro con tre accelerometri ortogonali e un magnetometro a flussometro elettronico triassiale attaccato al dewar. Questi dati sono stati analizzati usando tecniche di elaborazione dei segnali, soprattutto un cancellatore adattativo di rumori, per ridurre i rumori nei dati del gradiometro. I risultati mostrano qui che il rumore dell’esterno e/o il rumore del movimento del dewar possono essere ridotti di 40 dB in potenza di rumore. Si è anche mostrato che, nel caso di basso rapporto segnale-rumore (S/N∼1), può essere estratta un’onda sunusoidale di 10 Hz. Questa tecnica non solo promette riduzione dei rumori, ma ha anche lo scopo d’identificare i segnali di rumore che potrebbero essere veramente considerati parte del responso evocato. L’analisi dei dati che contengono i responsi evocati è ora in corso.
    Notes: Summary The noise spectrum of a superconducting second-derivative gradiometer has been investigated in an urban environment. Data have been acquired from the gradiometer with three orthogonal accelerometers and a triaxial fluxgate magnetometer attached to the dewar. These data have been analyzed by using signal processing techniques, primarily an adaptive noise canceller, to reduce noise in the gradiometer data. Results shown here indicate that the environmental noise and/or the dewar motion noise can be reduced as much as 40 dB in noise power. It is also shown, in the case of poor signal-to-noise ratio (S/N∼1), that a 10 Hz sine wave can be extracted. This technique not only shows promise for noise reduction, but also aids in the identification of noise signals which might be misconstrued as part of the evoked response. Analysis of data containing evoked response is now underway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455924
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  • 6
    Electronic Resource
    Electronic Resource
    Magnetic sensors with good signal-to-interference discrimination (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 153-165 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si stabiliscono princípi per il progetto di sistemi di spire che generano campi magnetici distanti che diminuiscono secondo una potenza inversa alta della distanza. Secondo un principio di reciprocità queste disposizioni, quando usate come sensori in magnetometri ad induzione e SQUID, hanno una sensibilità intrinsecamento bassa per sorgenti distanti del campo magnetico.
    Notes: Summary Principles are established for the design of coil arrays which generate distant magnetic fields diminishing as a high inverse power of the distance. By a principle of reciprocity these arrays, when used as sensors in induction and SQUID magnetometers, have an inherently low sensitivity to distant sources of magnetic field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455919
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  • 7
    Electronic Resource
    Electronic Resource
    Measurement of biomagnetic fields using multichannel superconducting-magnetometer techniques (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 166-174 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è costruito un magnetometro SQUID differenziale a 3 canali per la misurazione simultanea delle 3 componenti ortogonali del campo magnetico nella stessa posizione. Si descrive la struttura dell’apparecchio e si mostrano i dati MCG misurati. Si discutono gli effetti d’interferenza tra i canali.
    Notes: Summary We have constructed a three-channel differential SQUID magnetometer for the simultaneous measurement of the three orthogonal components of the magnetic field in the same location. The structure of the device is described and MCG data measured are shown. Interference effects between the channels are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455920
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  • 8
    Electronic Resource
    Electronic Resource
    Neuromagnetic measurements at hospital: Instrumentation and preliminary tests (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 184-194 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è costruito espressamente un sistema SQUID in un ospedale di Parigi, che permette indagini neuromagnetiche attinenti con applicazioni cliniche. Un gradiometro simmetrico di second’ordine lavora entro uno schermo per corrente parassite. Ciò è designato ad ottimizzare il costo e l’efficienza del sistema. Le sue prestazioni sono state sperimentate con dati da pazienti e da soggetti normali.
    Notes: Summary A SQUID system was specially built in a Parisian hospital, allowing neuromagnetic investigations dealing with clinical applications. A second-order symmetrical gradiometer works inside an eddy current shield. This was designed for optimizing the cost and the efficiency of the system. Its performances were tested with data from patients and normal subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455922
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  • 9
    Electronic Resource
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    A portable biomagnetic measuring system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 224-230 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si descrive la strumentazione per le applicazioni biomagnetiche. Le piccole dimensioni e la leggerezza del gradiometro SQUID permettono il facile trasporto e posizionamento dello strumento, rendendo cosí possibile le misurazioni biomagnetiche in una qualsiasi locazione in cui non ci siano rumori. L’apparecchio è provvisto di un alimentatore a batteria e, se riempito con 60 cm3 di elio liquido, funzionerà initerrottamente per 6 ore. L’apparecchio è adatto per la magnetocardiografia.
    Notes: Summary The instrumentation for biomagnetic applications is described. The small size and weight of the SQUID gradiometer permit easy transport and positioning of the instrument, thus making biomagnetic measurements possible in any noise-free location. The equipment is provided with a battery power supply, and, when filled with 60 cm3 of liquid helium, will operate continuously for 6 h. The device is suitable for magnetocardiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455926
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  • 10
    Electronic Resource
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    Comparison between measured and simulated magnetocardiograms in a case of anterolateral myocardial infarction (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 301-310 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si confrontano i magnetocardiogrammi misurati in un caso di infarto miocardico anterolaterale con i corrispondenti magnetocardiogrammi simulati. I cambiamenti piú notevoli nell’MCG misurato si sono osservati nelle parti superiori e inferiori del torace come previsto dalla simulazione.
    Notes: Summary The MCGs measured in a case of an anterolateral myocardial infarction were compared with the corresponding simulated MCGs. The most distinctive changes in the measured MCGs were observed in the upper and lower parts of the thorax as predicted by the simulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455933
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  • 11
    Electronic Resource
    Electronic Resource
    Determination of the spatial distribution of abnormal EEG and MEG from current dipole in inhomogeneous volume conductor (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 558-566 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La conduttività elettrica delle lesioni cerebrali varia con situazioni patologiche come l’edema e la calcificazione. È stato studiato mediante una simulazione con il computer l’effetto delle disomogeneità dei tessuti delle lesioni cerebrali sulle distribuzioni spaziali dei potenziali elettrici e dei campi magnetici sulla superficie del capo.
    Notes: Summary The electrical conductivity of brain lesions varies with pathological situations such as edema and calcification. The effect of the tissue inhomogeneities of brain lesions on spatial distributions of electrical potentials and magnetic fields over the surface of the head was studied by means of a computer simulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455954
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  • 12
    Electronic Resource
    Electronic Resource
    Diagnostic assessment of human iron stores by measurement of hepatic magnetic susceptibility (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 567-581 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è sviluppato un metodo magnetico per misurazioni dirette non invasive del ferro di immagazzinamento epatico umano con uno suscettometro SQUID. Le determinazioni magneticain vivo e chimicain vitro del ferro epatico non eme sono strettamente correlate. Le misurazioni magnetiche dei depositi di ferro sono utili, dal punto di vista clinico, nella diagnosi dei disordini nel metabolismo del ferro.
    Notes: Summary A magnetic method for direct noninvasive measurements of human hepatic storage iron with a SQUID susceptometer has been developed.In vivo magnetic andin vitro chemical determinations of liver nonheme iron are closely correlated. Magnetic measurements of iron stores are clinically useful in the diagnosis of disorders of iron metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455955
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  • 13
    Electronic Resource
    Electronic Resource
    The inverse problem in magnetopneumography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 594-607 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il problema inverso nella misurazione magnetical del polmone è stato studiato con un metodo che usa le ipotetiche distribuzioni del pulviscolo magnetico. Si sono fatte le minimizzazioni non vincolate e vincolate di una funzione obiettiva. Le simulazioni e l’analisi hanno mostrato l’efficacia del metodo.
    Notes: Summary The inverse problem in the magnetic measurement of the lung was studied with a method using hypothetical distributions of magnetic dust. Both unconstrained and constrained minimizations of an objective function were performed. Simulations and analysis showed the efficacy of the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455957
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  • 14
    Electronic Resource
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    A clinical system for accurate assessment of tissue iron concentration (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 582-593 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Questo lavoro descrive un nuovo suscettometro SQUID a doppio canale coadiuvato da computer destinato a raggiungere stime accuratein vivo delle concentrazioni di accumulo di ferro nei tessuti. Si discutono le considerazioni pratiche dello schema, la funzionalità sperimentale al rumore e la risoluzione clinica anticipata del nuovo sistema.
    Notes: Summary This paper describes a new computer-enhanced dual-channel SQUID susceptometer designed to achieve accuratein vivo estimates of tissue storage iron concentrations. We discuss the practical design considerations, instrumental noise performance and anticipated clinical resolution of the new system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455956
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  • 15
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    Magnetopneumography in welders: Observations on relaxation and clearance (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 608-616 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è trovato che la velocità di decadimento del campo residuo ottenuto tramite magnetizzazione delle particelle ferromagnetiche trattenute nei polmoni dei saldatori è associato a fattori come la quantità di polvere trattenuta, il curriculum lavorativo e la consuetudine di fumare. Una velocità di decadimento piú rapida appare correlata con un piú rapido smaltimento delle particelle di fumo di saldatura nei fumatori.
    Notes: Summary It was found that the rate of decay of the remanent field obtained through magnetization of ferrimagnetic particles retained in the lungs of are welders is associated with factors such as amount of dust retained, occupational history and smoking habits. A faster decay rate was found to correlate with a faster clearance of welding fume particles in smokers
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    URL: http://dx.doi.org/10.1007/BF02455958
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  • 16
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    Magnetic particles in the lung: A probe for alveolar macrophage function (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 617-623 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Particelle ferromagnetiche immesse per via intratracheale nei polmoni sono fagocitate da macrofagi alveolari. Dopo che queste particelle sono state magnetizzate dal campo esterno, esse producono un campo residuo che decade rapidamente a causa del disallineamento delle particelle dovuto al movimento citoplasmatico (rilassamento). I cambiamenti nel valore di rilassamento nel tempo successivo all’immissione potrebbero essere connessi alla mobilità citoplasmatica.
    Notes: Summary Ferrimagnetic particles instilled intratracheally into the lungs are phagocytized by alveolar macrophages. After these particles are magnetized by an external field, they produce a remanent field which decays rapidly due to particle misalignment from cytoplasmic motion (relaxation). Changes in relaxation rate with time following instillation might be related to cytoplasmic motility.
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    URL: http://dx.doi.org/10.1007/BF02455959
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  • 17
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    Magnetic-susceptibility plethysmography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 624-641 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La pletismografia a suscettività magnetica (MSPG) è un nuovo metodo proposto per controllare i cambiamenti del volume cardiaco. Si riesaminano il principio di misurazione e i lavori recenti di altri ricercatori. Si studia l’effetto del movimento legato al cuore della cassa toracica anteriore sul segnale MSPG.I risultati suggeriscono che il movimento del confine cassa toracica-aria può contribuire in modo significativo (∼75%) al segnale MSPG quando è registrato vicino al cuore.
    Notes: Summary Magnetic-susceptibility plethysmography (MSPG) is a new method proposed for monitoring cardiac-volume changes. The measurement principle and recent work by other investigators are reviewed. The effect of the cardiac-related motion of the anterior chest wall on the MSPG signal is studied. The results suggest that the motion of the chest-wall-air boundary may contribute significantly (∼75%) to the MSPG signal when recorded near the heart.
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    URL: http://dx.doi.org/10.1007/BF02455960
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  • 18
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    Magnetic signals from human skeletal muscles (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 642-649 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stata esaminata la forma d’onda d’impulso per il magnetomiogramma (MMG) dell’arto inferiore destro umano. Le durate tipiche degl’impulsi sono di circa (10÷20) ms. La variazione spaziale del MMG suggerisce un’origine nei muscoli anteriori della tibia.
    Notes: Summary The pulse wave form for the magnetomyogram (MMG) of the human right leg was examined. The typical pulse durations are about (10÷20) ms. The spatial variation of the MMG suggests a source in the anterior muscles.
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    URL: http://dx.doi.org/10.1007/BF02455961
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  • 19
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    d.c. Magnetic fields of the human leg as a function of position and relaxation (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 650-659 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Le ricerche sul campo magnetico intorno alla gamba umana con l’uso di un magnetometro SQUID producono risultati consistenti e riproducibili che possono essere rappresentati mediamente due linee di corrente, orientate inversamente, parallele all’asse della gamba. I campi sono condizionati dall’attività muscolare, che decade col tempo di rilassamento della gamba.
    Notes: Summary Investigations of the magnetic field around the human leg using a SQUID magnetometer yield consistent, reproducible results which can be modelled by 2 oppositely oriented line currents parallel to the leg axis. The fields are affected by muscle activity, decaying with the time of relaxation of the leg.
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    URL: http://dx.doi.org/10.1007/BF02455962
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  • 20
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    High-resolution recordings of the magnetic activity of the His-Bundle in man (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 1110-1118 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto L'attività del sistema di His-Purkinje è stata misurata magneticamente usando un magnetometro SQUID nella camera schermata magneticamente di Berlino (BMSR) e usando in aggiunta filtraggio (banda passante da 0.5 Hz a 300 Hz) e tecniche di mediazione. La camera riduce il livello di rumore di fondo a meno di 4 $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ nella regione a spettro bianco. All'interno dell'intervalloPR è stata osservata una struttura a rampa, la cui pendenza cambia segno attraversando la linea mediana del cuore. In aggiunta, sono stati registrati segnali ben definiti approssimativemente 40 ms prima dell'inizio dell'attivazione ventricolare.
    Abstract: Резюме йзмеряется активность НР системы у человека с помощью SQUID магнетометра в Берлинской магнитно экранированной комнате, используя фильтртрацию полосы пропускания (ширина полосы от 0.5 Гц до 300 Гц) и усреднение. Берлинская магнитно экранированная комната уменьшает уровень фонового шума до величины $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ в области белого шума. ВнутриPR интервла наблюдается диаграмма с уклоном, причем величина ыклона меняется при пересечении медианной линии сердца. Кроме того, ориблизительно за 40 мс до наступления активности желудочка регистрируются определенные сигналы.
    Notes: Summary The activity of the His-Purkinje system (HPS) in man has been measured magnetically with a SQUID magnetometer in the Berlin magnetically shielded room (BMSR) by using in addition band pass filtering (band width 0.5 Hz to 300 Hz) and averaging. The BMSR reduces the background noise level to less than $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ in the region of white noise. Within thePR interval a ramp pattern was observed, changing its slope when crossing the median line of the heart. In addition, definite signals were recorded approximately 40 ms before the onset of ventricular activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457146
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    An eddy-current-shielded room with a partially closed entrance (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 195-202 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si mostra che miglioramenti sostanziali possono essere ottenuti nelle proprietà di schermatura di una stanza schermata da corrente parassite coprendo l’accesso con lamine conduttrici. I risultati suggeriscono che non è necessario installare una porta conduttrice e mostrano che è il caso di coprire una piccola parte della porta in modo permanente.
    Notes: Summary We show that substantial improvements can be obtained in the shielding properties of an eddy-current-shielded room by covering the doorway with conductive plates. Results suggest that it is unnecessary to install a conductive door and show that it is worthwhile covering a small part of the doorway permanently.
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    URL: http://dx.doi.org/10.1007/BF02455923
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    High-resolution recordings of thePR segment in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 248-254 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il magnetocardiogramma ad alta risoluzione è stato registrato mediante magnetometri superconduttori in 12 volontari sani utilizzando la camera schermata di Berlino per ridurre il livello di rumore elettromagnetico. La morfologia del trattoPR magnetico è caratterizzata dalle «rampe» in precedenza osservate, sulle quali s’inseriscono segnali. A volte la forma d’onda appare complessa.
    Notes: Summary ThePR interval of magnetocardiograms has been measured with a SQUID sensor in the Berlin magnetically shielded room. In addition to previously reported ramps with isolated superimposed signals in several cases a structured morphology has been found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455928
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    Atrial activity during thePR segment of the MCG (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 266-279 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati osservati segnali degradanti nel segmentoPR dei magnetocardiogrammi normali registrati da 5 cani. Sono state osservate rampe maggiori dopo aver indotto con farmaci il blocco del nodo atrioventricolare di primo grado, ed è stata osservata una completa ripolarizzazione atriale a seguito d’isolate contrazioni atriali in due animali con blocco di secondo grado. Queste rampe, che variano fino a 6.7 pT in ampiezza e provengono dagli atri, possono complicare l’individuazione magnetica dell’attività di His-Purkinje.
    Notes: Summary Sloping signals were observed in thePR segment of normal magnetocardiograms recorded from five dogs. Larger ramps were observed after first-degree AV nodal blockade was induced pharmacologically, and complete atrial repolarization was observed following isolated atrial contractions in two animals with second-degree block. These ramps, ranging up to 6.7 pT in size and arising from the atria, may complicate magnetic detection of His-Purkinje activity.
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    URL: http://dx.doi.org/10.1007/BF02455930
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    High-resolution magnetic measurements of human cardiac electrophysiological events (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 231-247 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La motivazione fondamentale per lo studio dei fenomeni elettrofisiologici cardiaci tramite il metodo biomagnetico è dovuta al fatto che questa tecnica offre un’alta risoluzione spaziale e sembra fornire informazioni complementari rispetto alle sole registrazioni elettriche. Fino ad oggi l’interesse degli studiosi si è concentrato su due differenti fenomeni cardiaci: 1) lo studio dell’attività del sistema di conduzione atrioventricolare e 2) lo studio della depolarizzazione ventricolare anormalmente ritardata (late potentials). L’interesse clinico per lo studio non invasivo del sistema di His-Purkinje (HPS) è ben noto. Registrazioni cliniche non invasive di late potentials sono particolarmente desiderabili in quanto possono essere preziosi indicatori di rischio di morte improvvisa. In questo lavoro si presenta una rassegna sullo stato delle ricerche in entrambi i campi d’indagine.
    Notes: Summary The fundamental motivation for investigating cardiac electrophysiological phenomena by means of the biomagnetic method has been that this technique should have added spatial resolution and provided complementary information as opposed to electric recordings only. So far the interest of experimentalists has been concentrated on two different kinds of cardiac phenomena: 1) the study of the activity of the cardiac conduction system and 2) of abnormally delayed ventricular depolarization (late potentials). The clinical interest for the noninvasive investigation of the His-Purkinje system (HPS) is well known. Noninvasive clinical recording of late potentials is particularly desirable as they seem to be precious markers for risk of sudden death. A review of the state of research in both fields is presented in this paper.
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    URL: http://dx.doi.org/10.1007/BF02455927
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    Magnetic measurements and modelling for the investigation of the human-heart conduction system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 280-290 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Ein dal 1980 è iniziato uno studio sistematico dell’attività del sistema di His-Purkjnje (HPS) su soggetti normali e patologici con il metodo biomagnetico. Allo scopo di risolvere il problema di quanta parte dei segnali misurati sia attribuibile al sistema di His-Purkinje e quanta piuttosto alla ripolarizzazione atriale, è stata recentemente sviluppata una strumentazione appositamente disegnata per misure sul HPS e con una sensibilità di $$20fT/\sqrt {Hz}$$ nella banda di frequenze interessanti ((0.5÷300) Hz). Al contempo si è altresí sviluppato un nuovo modello teorico in stretta corrispondenza con le caratteristiche anatomiche del HPS che fornisce una distribuzione di campo magnetico sul torace in buon accordo qualitativo con i risultati sperimentali.
    Notes: Summary Since 1980, systematic investigations of the activity of the His-Purkinje system (HPS) by the biomagnetic method have been reported on both normal subjects and patients affected by different kinds of conduction disturbances. A first attempt to interpret the experimental results by means of a theoretical model satisfactorily accounted for the measured «ramp» patterns. Moreover, a good temporal coincidence was observed between magnetic signals and invasively recorded His bundle electrograms (HBE). An alternative explanation of the «ramp» pattern, in terms of atrial repolarization, has been recently proposed on the basis of animal experimental investigation. In order to try to solve this problem, we have carried out a twofold approach: a new second-order gradiometer, specifically designed for HPS activity investigation has been successfully set up and tested; it provides a sensitivity of $$20fT/\sqrt {Hz}$$ in the band width of interest ((0.5÷300) Hz). Second, a new model based on a closer correspondence to anatomical features of the HPS has been developed. This model provides well-defined patterns which are in quite good agreement with experimental results.
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    URL: http://dx.doi.org/10.1007/BF02455931
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    The mapping of the measured cardiac electric potential and magnetic-field distribution (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 311-323 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si registra la distribuzione sia del potenziale elettrico cardiaco sulla superficie del corpo che del campo magnetico cardiaco vicino al torace e alla schiena in momenti fissi del ciclo cardiaco. Le caratteristiche generali di entrambi i tipi di mappa sono semplici e riproducibili, inoltre ciascuno di essi fornisce informazioni differenti.
    Notes: Summary The distribution of both the cardiac electric potential on the body surface and the cardiac magnetic field near the chest and back is recorded at fixed time instants of the heart cycle. The general features of both types of maps are simple and reproducible, moreover they both reveal different information.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455934
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    The influence of inhomogeneities on the cardiac-magnetic-field distribution (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 324-339 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati eseguiti calcoli numerici sul campo magnetico generato dal cuore durante la depolarizzazione ventricolare. Lo scopo di questo lavoro è studiare il contributo d’inomogeneità nel conduttore di volume al campo totale e stabilire l’influenza dei gradiometri usati nelle registrazioni sperimentali.
    Notes: Summary Numerical computations were performed on the magnetic field generated by the heart during ventricular depolarization. The purpose of this study was to investigate the contribution of inhomogeneities in the volume conductor to the total field and to establish the influence of gradiometers as used in experimental recordings.
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    URL: http://dx.doi.org/10.1007/BF02455935
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    High-resolution magnetocardiographic recordings of theST segment in patients with electrical late potentials (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 340-345 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il magnetocardiogramma ad alta risoluzione, registrato in 22 pazienti affetti da pregresso infarto del miocardio, ha permesso di rilevare in 3 casi la presenza di segnali di ampiezza tra 0.4 e 3 pT temporalmente correlati a depolarizzazioni tardive elettriche. Si discutono de differenze tra segnali magnetici ed elettrici e il loro possibile significato fisiopatologico.
    Notes: Summary High-resolution magnetocardiograms of patients with recent myocardial infarction have been recorded. In three cases, signals have been found in theST segment that are time correlated with simultaneously recorded late electric potentials.
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    URL: http://dx.doi.org/10.1007/BF02455936
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    On the influence of the volume conductor in magnetocardiography: an experimental approach (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 346-355 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Per studiare l’effetto della geometria del conduttore di volume, sono stati compiuti esperimenti usando cuori di coniglio isolati. È stato osservato un aumento del segnale magnetico con l’aumentare della dimensione del conduttore di volume. Si discutono i risultati usando un dipolo di corrente a origine fissa e un modello di sorgente di tensione per il cuore.
    Notes: Summary To study the effect of the volume conductor geometry on the MCG, experiments using isolated rabbit hearts were done. An increase of the magnetic signal when increasing the volume conductor’s size was observed. The results are discussed by using a fixed-origin current dipole and a voltage source model for the heart.
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    URL: http://dx.doi.org/10.1007/BF02455937
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    First magnetic measurements of action currents in isolated cardiac Purkinje fibers (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 368-378 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano le prime misurazioni del campo magnetico associato col potenziale d’azione in un fascio di fibre cardiache di Purkinje isolate. Le nostre scoperte dimonstrano la fattibilità dell’uso di tecniche magnetiche per misurare le correnti assiali in un gruppo di cellule cardiache ad attività spontanea.
    Notes: Summary We present the first measurements of the magnetic field associated with the action potential in a bundle of isolated cardiac Purkinje fibers. Our findings demonstrate the feasibility of using magnetic techniques to measure the axial current in a bundle of spontaneously active cardiac cells.
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    URL: http://dx.doi.org/10.1007/BF02455939
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    Retinotopic map on the visual cortex for eccentrically placed patterns: First noninvasive measurement (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 410-419 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il campo magnetico corticale osservato, suscitato da uno stimolo presentato a varie eccentricità nel campo visivo, è stato interpretato come derivante da dipoli di corrente lungo la scissura longitudinale. La profondità della sorgente aumenta con l’aumento dell’eccentricità, in accordo con la classica mappatura retinotopica.
    Notes: Summary The observed cortical magnetic field evoked by a stimulus presented at various eccentricities in the visual field was interpreted as arising from current dipoles along the longitudinal fissure. The depth of the source increased as the eccentricity was increased, in agreement with the classical retinotopic map.
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    URL: http://dx.doi.org/10.1007/BF02455941
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    Neuromagnetic localization of two components of the transient visual evoked response to patterned stimulation (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 420-428 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si esamiano i componenti elettrici e magnetici della risposta stimolata visiva del cervello, con picchi a 120 e 180 ms dopo lo stimolo. I risultati mostrano che entrambi i componenti magnetici sono localizzati nella corteccia occipitale superficiale tangenziale al cuoio capelluto. La distribuzione diM120 suggerisce che i generatori dei componenti elettrici e magnetici sono correlati, ma il campo magnetico elettrico registrato è una modificazione elaborata di quello prodotto dalla sorgente.
    Notes: Summary Corresponding electrical and magnetic components of the brain’s visual evoked response peaking at 120 and 180 ms poststimulus are examined. Results show that both magnetic components are localized in the superficial occipital cortex tangential to the scalp. The distribution ofM120 suggests that the generators for the electrical and magnetic components are related, but the electrical field recorded is an elaborate modification of that produced by the source.
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    URL: http://dx.doi.org/10.1007/BF02455942
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    Somatosensory evoked magnetic fields: Mappings and the influence of the stimulus repetition rate (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 429-437 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Campi magnetici indotti dalla sensibilità somatica sono stati confrontati con i corrispondenti potenziali elettrici sul cuoio capelluto allo scopo di studiare le loro sorgenti neurali. Le mappature delle risposte magnetiche hanno mostrato attività a livello delle cortecce di sensibilità somatica primarie e secondarie. Ulteriori sorgenti oltre a queste aree sembrano essere coinvolte nella generazione dei potenziali del cuoio capelluto a vertice somatosensoriali.
    Notes: Summary Somatosensory evoked magnetic fields were compared with corresponding electric scalp potentials in order to study their neural sources. Mappings of the magnetic responses showed activity at the primary and secondary somatosensory cortices. Additional sources besides these areas seem to be involved in the generation of the somatosensory vertex scalp potentials.
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    URL: http://dx.doi.org/10.1007/BF02455943
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    Some tentative model considerations based on experimental neuromagnetic data (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 438-459 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si presentano alcuni tentativi di considerazioni modello, basati sul concetto di dipolo di corrente equivalente per tener conto delle risposte sonore stimolate osservate, con lo scopo di tentare un confronto delle variazioni in ampiezza e latenza con calcoli basati sul modello di nervo altamente semplificato di Rall. Si presenta un’analisi fenomenologica dei dati sperimentali sul campo magnetico sonoro tardo evocato dalla corteccia uditiva umana. Qui si pone l’accento sulle relazioni tra le proprietà del segnale (per esempio, ampiezza e latenza) e tra le proprietà del segnale e le proprietà dello stimolo (per esempio, ampiezza/latenza e frequenza in discesa relativa Δf/f per uno stimolo con frequenza in discesa) piuttosto che su problemi correlati con la posizione del dipolo di corrente equivalente, per esempio l’organizzazione tonotopica discussa da Elberlinget al. e Romaniet al. Si presentano alcuni risultati di un calcolo numerico basato su un modello a cavo lineare e li si confronta con i risultati sperimentali.
    Notes: Summary In this paper we present some tentative model considerations, based on the concept of an equivalent current dipole to account for observed auditory evoked responses, with the aim of attempting a comparison of variations in amplitude and latency with calculations based on Rall’s greatly simplified nerve model. A phenomenological analysis of experimental data on the late, auditory evoked magnetic field from the human auditory cortex is presented. The emphasis is here placed on relations between signal properties (e.g. amplitude and latency) and between signal properties and stimulus properties (e.g. amplitude/latency and relative frequency glide Δf/f for a frequency glide stimulus) rather than on questions related to the location of the equivalent current dipole,e.g. the tonotopic organization discussed by Elberlinget al. and by Romaniet al.. Some results of a numerical calculation based on a linear-cable model are presented and compared with experimental results.
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    URL: http://dx.doi.org/10.1007/BF02455944
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    Studies of auditory evoked magnetic and electric responses: Modality specificity and modelling (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 471-483 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Le sorgenti di risposte uditive magnetiche ed electtriche stimolate sono state formate con dipoli a corrente multipli. L’attività a livello delle cortecce uditive, 2.6 cm al di sotto della calotta cranica, spiega la distribuzione di campo osservata $$\overline {N100m}$$ . Un’ulteriore sorgente di corrente vicino al vertice è necessaria per spiegare le corrispondenti distribuzioni di potenziale. La posizione delle sorgenti di corrente di $$\overline {N100m}$$ non ha mostrato alcuna dipendenza sistematica dalla frequenza tonale.
    Notes: Summary The sources of auditory evoked electric and magnetic responses were modelled with multiple current dipoles. The activity at the auditory cortices, 2.6 cm beneath the skull, explains the observed $$\overline {N100m}$$ field distribution. An additional current source near the vertex is needed to explain the corresponding potential distributions. The locations of the current sources of $$\overline {N100m}$$ did not show any systematic dependence on the tonal frequency.
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    URL: http://dx.doi.org/10.1007/BF02455946
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    Auditory evoked magnetic fields: a replication, with comments on the magneticP50 analog (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 460-470 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati registrati campi magnetici uditivi indotti (AEF) e potenziali uditivi indotti EEG (AEP) dalle regioni corticali uditive destra e sinistra di 12 soggetti normali adulti. Il sensore magnetico era un gradiometro SQUID a forma di otto con una linea di base di 4 cm orientato in modo da essere massimamente sensibile a un dipolo di corrente orientato perpendicolarmente alla fissure di Sylvio. Gli stimoli erano impulsi sonori di 1 kHz, lunghi 100 ms con un intervallo modale tra stimoli di 700 ms emessi a livelli di pressione sonora di 40, 60, 80 e 100 dB. Si è trovato che l’ampiezza AEF è correlata all’intensità dello stimolo in modo quadratico, l’ampiezza AEP in modo, lineare. Gli AEF erano di ampiezza maggiore in risposta alla stimolazione contralaterale che in risposta alla stimolazione ipsilaterale. Gli AEP non presentano questa relazione. In un secondo esperimento gli AEF e AEP dell’emisfero destro in risposta al tono di stimolazione nell’orecchio controlaterale in questi 12 soggetti sono stati combinati con dati simili precedenti su 24 soggetti, ottenendo cosí un totale di 36 soggetti, per esaminare la comparabilità della forma dell’onadaP50 di AEP e dell’analogaP50 di AEF. Si è trovato che la latenza dellaP50 decrese in funzione dell’intensità crescente dello stimolo sia per AEF che per AEP, e che la latenza diP50 è decisamente inferiore nelle registrazioni magnetiche rispetto alle registrazioni del potenziale.
    Notes: Summary Auditory evoked magnetic fields (AEFs) and EEG auditory evoked potentials (AEPs) were recorded from left and right auditory cortical regions of 12 normal adult subjects. The magnetic sensor was a figure-eight SQUID gradiometer with a 4 cm baseline oriented so as to be maximally sensitive to a current dipole oriented normal to the Sylvian fissure. Stimuli were 100 ms long 1 kHz tone pips with a modal interstimulus interval of 700 ms delivered at sound pressure levels of 40, 60, 80 and 100 dB. AEF amplitude was found to be related to stimulus intensity in a quadratic fashion, AEP amplitude in a linear fashion. AEFs were of larger amplitude in response to contralateral as compared to ipsilateral stimulation. AEPs did not exhibit such a relationship. In a second experiment right-hemisphere AEFs and AEPs in response to contralateral ear tone stimulation in these 12 subjects were combined with similar previous data from 24 subjects, providing a total of 36 subjects, to examine the comparability of the AEPP50 wave form and the AEFP50 analog. The latency of theP50 was found to decrease as a function of increasing stimulus intensity for both AEFs and AEPs, and theP50 latency was consistently shorter in magnetic compared to potential recordings.
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    Cerebral magnetic fields associated with voluntary limb movements in man (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 484-494 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto I movimenti volontari degli arti sono preceduti da spostamenti MEG che cominciano già 1.2s prima del movimento. Questi spostamenti invertono la polarità sull’area di rappresentazione della corteccia motoria dell’arto in questione.
    Notes: Summary Voluntary limb movements are preceded by MEG shifts beginning even as early as 1.2 s before the movement. These shifts reverse polarity above the cortical motor representation area of the limb concerned.
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    URL: http://dx.doi.org/10.1007/BF02455947
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    Slow magnetic fields of the brain preceding movement and speech (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 495-504 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati registrati i campi magnetici del cervello che precedono i movimenti autonomi delle dita della mano, del piede e della dita del piede stesso, i movimenti delle dita della mano e del piede causati da uno stimolo e la parola. Sono stati trovati lenti spostamenti dei campi magnetici con morfologia simile ai coincidenti potenziali elettrici, ma con distribuzioni molto diverse. Si discutono le deduzioni ottenute dai dati sulla localizzazione dei generatori cerebrali.
    Notes: Summary Magnetic fields of the brain were recorded preceding selfinitiated finger, foot, toe movements, stimulus-triggered finger and toe movements, and speech. Slow magnetic-field shifts were found with morphology similar to coincident electrical potentials, but with very different distributions. Inferences from the data about localization of cerebral generators were discussed.
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    URL: http://dx.doi.org/10.1007/BF02455948
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    Magnetic fields associated with the brain’s response to infrequent events (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 505-511 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è studiato il campo magnetico prodotto dal cervello prendendo in considerazione una varietà di eventi rari. Si riporta il carattere temporale della risposta a un raro stimolo uditivo. Il campo magnetico appare offrire un’utile nuova sonda dell’attività endogena nel cervello umano.
    Notes: Summary We have studied the magnetic field produced by the brain when attending to a variety of rare events. The temporal character of the response to a rare auditory stimulus is reported. The magnetic field appears to offer a useful new probe of endogeneous activity in the human brain.
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    URL: http://dx.doi.org/10.1007/BF02455949
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    Magnetic study of the spontaneous brain activity of normal subjects (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 538-546 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Uno studio sull’attività spontanea del cervello in soggetti normali è stato eseguito con il metodo neuromagnetico. Sono stati usate 2 diverse strumentazioni per le misure magnetiche. Ambedue usavano gradiometri di second’ordine disegnati specificatamente per gli studi sul cervello: 2.9 cm di diametro, 5 cm di baseline. Uno SQUID r.f. e uno SQUID d.c. erano accoppiati ai gradiometri. I livelli di rumore misurati sono stati rispettivamente di $$40fT/\sqrt {Hz}$$ e $$25fT/\sqrt {Hz}$$ . In alcuni soggetti sono state effettuate mappe di campi magnetici generati dall’attività spontanea del cervello. Le mappe dell’ampiezza media dei segnali del ritmo α hanno mostrato 2 massimi dell’attività su 2 regioni simmetriche dello scalpo. Comunque, malgrado una generale simmetria fra gli emisferi, la complessità delle mappe misurate suggerisce una corrispondente complessità dei generatori responsabili dell’attività α.
    Notes: Summary An investigation of the spontaneous brain activity from normal subjects has been carried out by means of the neuromagnetic method. Two different systems were used for magnetic measurements. Both used 2nd-order gradiometers specifically designed for brain studies: 2.9 cm diameter, 5 cm baseline. A r.f. SQUID and a d.c. SQUID were coupled to the gradiometers. The measured noise levels are $$40fT/\sqrt {Hz}$$ and $$25fT/\sqrt {Hz}$$ , respectively. Thorough magnetic mapping of the spontaneous activity was performed on a few subjects. By mapping the average amplitude of the α-rhythm signals two maxima of activity over two symmetric regions of the scalp were clearly observed. Despite a general symmetry between hemispheres, however, the complexity of the measured maps suggests a corresponding complexity of the generators responsible for α-activity.
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    Alternatives to the SQUID magnetometer for some biomagnetic measurements (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 214-223 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si discutono magnetometri del tipo del flussometro elettronico e di risonanza (precisione libera, pompata otticamente) che possono in qualche caso sostituire il magnetometro SQUID. Si descrivono i princípi di funzionamento, la sensibilità, l’intervallo dinamico e la risposta di frequenza. Si dà un accenno riguardo l’applicazione di questi magnetometri nelle misurazioni biomagnetiche.
    Notes: Summary Flux gate and resonance type of magnetometers (free precession, optically pumped), which can in some cases replace the SQUID magnetometer, are discussed. The principles of operation, sensitivity, dynamical range and frequency response are described. The application of these magnetometers for biomagnetic measurements is mentioned.
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    The magnetic field produced by the conduction system of the human heart (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 255-265 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stata sfruttata la risoluzione spaziale del sensore magnetico per fornire stime numeriche del contributo atriale ai campi magnetici registrati esattamente prima della depolarizzazione ventricolare. Si trova che il contributo è piccolo, e questo rafforza l’interpretazione originale secondo la quale questi campi derivano principalmente dal sistema di conduzione del cuore.
    Notes: Summary We have exploited the spatial resolution of the magnetic sensor to provide numerical estimates of the atrial contribution to magnetic fields recorded just prior to ventricular depolarization. The contribution is found to be small, strenghening our original interpretation that such fields originate mostly in the conduction system of the heart.
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    High-resolution isofield mapping in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 291-300 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano i risultati preliminari ottenuti costruendo mediante computer mappe di distribuzione di campo magnetico sulla base di registrazioni ad alta risoluzione effettuate con magnetometro superconduttore. La procedura è stata applicata per esaminare i MCG di 16 pazienti affetti da pregresso infarto del miocardio. Sulla base di questa elaborazione è stato possibile dividere i pazienti in due classi, una delle quali contiene tutti i pazienti con depolarizzazioni tardive.
    Notes: Summary A possible clinical application of a high-resolution magnetic isofield contour mapping technique in cardiography is discussed. Preliminary results are presented in applying this technique to patients with recent myocardial infarction. The patients could be divided into two classes; one of them contains patients with electrical late potentials as a subclass.
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    Magnetic measurements of action currents in an isolated lobster axon (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 512-516 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano le prime misurazioni del campo magnetico prodotto da correnti di azione che si propagano lungo l’assone singolo di un nervo gigante. Questi dati sono stati ottenuti con un trasduttore a bobina toroidale e un amplificatore o semiconduttore a temperatura ambiente.
    Notes: Summary We present the first measurements of the magnetic field produced by action currents propagating along a single giant nerve axon. These data were obtained with a toroidal pick-up coil and a room temperature semiconductor amplifier.
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    URL: http://dx.doi.org/10.1007/BF02455950
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    Clinical magnetoencephalography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 517-537 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Finora la magnetoencefalografia spontanea (MEG) in soggetti normali e patologici non è stata investigata a fondo. Si conoscono pochissimi contributi in questo campo. A parte il lavoro del gruppo di biomagnetismo di Roma, il solo contributo clinico finora è stato quello di Hughes e collaboratori che era abbastanza limitato nel numero e nella scelta dei soggetti studiati. La nostra esperienza condotta fin dal 1980 su un gran numero di casi (principalmente epilessie focali) mostra che il MEG può evidenziare attività significative anche se non sono presenti anormalità EEG; esso ha inoltre una risoluzione spaziale maggiore rispetto all’EEG. I foci epilettici mostrano un’area limitata di attività massima. Finora non è stata osservata nessuna evidenza sperimentale di una differente distribuzione delle ampiezze del campo sullo scalpo. La risoluzione spaziale del MEG riguarda anche la possibilità di risolvere la morfologia dei segnali EEG (per esempio onde aguzze EEG risolte in gruppi di spikes dal MEG) o di separare topograficamente le anormalità EEG mescolate e non ben localizzate (per esempio, attività delta ed epilettiche mescolate nell’EEG e discriminate nel MEG). I migliori risultati si osservano quando la localizzazione è nella corteccia esterna. Dopo una descrizione del materiale studiato, si sottolinea l’importanza dei risultati ottenuti per la prima volta in casi di epilessie focali.
    Notes: Summary So far spontaneous magnetoencephalography (MEG) in normal and pathological subjects has not been deeply investigated. Very few contributions in this field are available. Aside from the work of the Rome biomagnetic group in this field, the only clinical contribution up to now has been that of Hughes and co-workers which was rather limited in the number and in the selection of subjects investigated. Our experience, carried out since 1980 on a large number of cases—mainly focal epilepsies— shows that the MEG may evidence significant activities even if EEG abnormalities are not present and has a higher spatial resolution with respect to the EEG. Epileptic foci show a limited area of maximal activity. So far no experimental evidence of a different distribution of field amplitude over the scalp has been observed. The spatial resolution of the MEG also regards the possibility of resolving the morphology of EEG signals (for instance, EEG sharp waves resolved into groups of spikes by MEG) or topographically separate EEG abnormalities mixed up and not well localized (for instance, delta and epileptic activities mixed up in the EEG, but differently in the MEG). The best results are observed when the localization is in the outer cortex. After a description of the material studied, the importance of the results obtained for the first time in cases of focal epilepsies is outlined.
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    Localization of epileptic foci by means of biomagnetic measurements (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 547-557 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Durante l’ultimo anno gli autori hanno condotto una ricerca sistematica su un gran numero di soggetti patologici registrando simultaneamente l’EEG e il MEG. La presente versione del nostro apparato sperimentale permette di effettuare misure MEG con un solo sensore magnetico, impedendo la rilevazione simultanea di attività MEG su punti differenti della testa. Ciò ha condotto gli autori a concentrarsi sulle epilessie focali. Fin dalle prime misure il sensore magnetico ha dimostrato un notevole potere localizzante, rafforzando l’interesse per la localizzazione in casi patologici. In questo lavoro si riportano risultati che sembrano confermare la straordìnaria capacità delle misure MEG nel localizzare sorgenti di attività cerebrali patologiche in casi di epilessie focali.
    Notes: Summary During the last year the authors have been carrying out a systematic investigation on a large number of pathological subjects simultaneously recording the EEG and the MEG. The present version of our experimental apparatus allows MEG measurements with only one magnetic detector, thus preventing the detection of simultaneous MEG activities over different points of the head. This has led the authors to concentrate upon focal epilepsies. Since the first measurements a remarkable localizing power was shown by the magnetic detector, thus strengthening the interest in pathological localization. In this contribution we report results which seem to confirm the extraordinary capability of MEG measurements to localize sources of pathological brain activities in cases of focal epilepsies.
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    Regulation of plasma 1,25-(OH)2-D3 by phosphate: Evidence against a role for total or acid-soluble renal phosphate content (1983)
    Springer
    Calcified tissue international 35 (1983), S. 773-777 
    Details
    ISSN: 1432-0827
    Keywords: 1,25-(OH)2-D3 ; Hypophysectomy ; Growth hormone ; Phosphorus ; 31P NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In order to evaluate a possible role for tissue phosphate or phosphorylated compounds in mediating the increase in plasma 1,25-(OH)2-D3 levels during dietary phosphate deprivation, measurements of total and acid-soluble renal cortical phosphate content have been made in both intact and hypophysectomized (hypox) rats eating a normal diet and also after four days of dietary phosphate deprivation. Similar measurements were also made in phosphate-deprived hypophysectomized rats replaced with growth hormone (GH). Total and acid-soluble renal cortical phosphate content averaged 81±8 µmol/g and 4.1±0.6 µmol/g, respectively, in intact rats eating the normal diet and were not significantly altered after phosphate deprivation despite a fall in plasma phosphate of about 40% and a fourfold increase in plasma 1,25-(OH)2-D3 levels. Total and acid-soluble renal cortical phosphate content levels were higher in hypox rats, averaging 92±8 µmol/g and 4.9±0.7 µmol/g, respectively, but also did not change after phosphate deprivation. Replacement of phosphate-deprived hypox rats with GH resulted in a further fall in plasma phosphate and a significant increase in plasma 1,25-(OH)2-D3 levels, but there was no change in either total or acid-soluble renal cortical phosphate content. The distribution of organophosphorus compounds in the acid-soluble phosphate fraction in these experiments was also evaluated using31P NMR spectroscopy. Although there appeared to be an increase in the total concentration of organophosphorus compounds after phosphate deprivation, this effect was not altered by hypophysectomy or by replacement of phosphate-deprived hypox rats with GH. These data suggest that unless phosphate deprivation affects only a small or specific cellular phosphate pool, some factor other than renal cell inorganic phosphate content must initiate the increase in renal 1,25-(OH)2-D3 synthesis that occurs during phosphate deprivation.
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    31P NMR as a spectroscopic monitor of the spontaneous precipitation of calcium phosphates (1983)
    Springer
    Calcified tissue international 35 (1983), S. 284-286 
    Details
    ISSN: 1432-0827
    Keywords: Phosphorus ; NMR ; Precipitation ; Nucleation ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary High-resolution31P NMR spectroscopy is shown to be a potentially valuable new method for monitoring the spontaneous precipitation of calcium phosphates from metastable supersaturated solutions. An apparatus capable of pH-statting the sample in a spinning 20 mm NMR sample tube is briefly described. The spontaneous precipitation of dicalcium phosphate dihydrate, CaHPO4· 2H2O, pH-statted at pH 5, is characterized by a base-uptake curve which follows the decrease in the intensity of the solution31P resonance. The precipitation of amorphous calcium phosphate at neutral pH, which exhibited an induction period of ∼ 10 min, was also studied. No evidence of NMR peaks from transient clusters or the initial colloidal solid phase has been seen.
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    Growth hormone and triiodothyronine permit an increase in plasma 1,25(OH)2D concentrations in response to dietary phosphate deprivation in hypophysectomized rats (1983)
    Springer
    Calcified tissue international 35 (1983), S. 100-106 
    Details
    ISSN: 1432-0827
    Keywords: 1,25(OH)2D ; Hypophysectomy ; GH ; T3 ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Hypophysectomy abolishes the four- to fivefold increase in plasma 1,25(OH)2D levels that normally accompanies dietary phosphate deprivation in rats despite a smaller but significant decrease in plasma phosphate in these animals. This effect appears within 1 week of hypophysectomy and may be the result of a lack of GH, T3, or some other pituitary hormone. In hypothyroid rats (2 weeks after TPTX) not given replacement T3, plasma 1,25(OH)2D levels rose threefold from 148±57 pmol/l to 402±96 pmol/l (mean±SD) after 4 days of dietary phosphate deprivation. However, in hypophysectomized animals given replacement T3 alone, plasma 1,25(OH)2D levels rose fourfold from 82±13 to 333±230 pmol/l after 4 days of phosphate deprivation. In addition, in hypophysectomized animals replaced with GH alone, plasma 1,25(OH)2D levels rose from 243±86 to 525±85 pmol/l during phosphate deprivation. These results would suggest that both GH and T3 must be absent to prevent enhanced renal 1,25(OH)2D synthesis during phosphate deprivation. GH and T3 appear to play a permissive role since plasma levels of these hormones do not increase when intact rats are deprived of phosphate. Furthermore, bioassayable somatomedin levels are also not increased in intact rats during phosphate deprivation as well as plasma levels of prolactin. As observed previously, plasma 1,25(OH)2D levels were inversely correlated to plasma phosphate concentrations (r=0.46,P〈0.025), despite the inclusion of data points for unreplaced hypophysectomized animals who were hypophosphatemic but showed no increase in plasma 1,25(OH)2D. Thus the possibility remains that GH and T3 may exert their effect by permitting the renal 25OHD-1α-hydroxylase to respond to a change in phosphate concentrations during dietary phosphate deprivation, that, in turn, may ultimately increase renal 1,25(OH)2D synthesis and plasma levels of this hormone.
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    Rotifers as indicators of water quality (1983)
    Springer
    Hydrobiologia 100 (1983), S. 169-201 
    Details
    ISSN: 1573-5117
    Keywords: rotifers ; saprobity ; saprobic valence ; indicative weight of species ; saprobic index ; pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Six hundred and twenty species and lower taxonomical units of Rotatoria found in Czechoslovakia and surrounding countries are listed alphabetically and classified according to water quality. The numerical characteristics include the saprobic valence in 10 balls, the indicative weight of species, Ii, and the individual saprobic index, Si. Rotifers are considered to be good indicators and some of them are figured on Plates 1–3. The situation is illustrated by four graphs and the relation to BOD5 values is stressed. All rotifers are aerobic organisms and occur only within limnosaprobity. They can also serve as indicators of trophic conditions. To characterize the situation in standing and slowly flowing waters a Brachionus: Trichocerca quotient is proposed. Rotifers can also be used as test organisms in toxicity experiments.
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    Removal of nitrogen, phosphorus and potassium by rice-wheat double cropping system as affected by duration of rice variety, methods of planting rice and levels and sources of nitrogen (1983)
    Springer
    Plant and soil 70 (1983), S. 287-295 
    Details
    ISSN: 1573-5036
    Keywords: Neem cake coated urea ; Nitrogen ; Phosphorus ; Potassium ; Rice ; Rice-wheat ; Sulphur coated urea ; Urea ; Urea briquette
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Removal of NPK in the rice-wheat double cropping system was studied in a field experiment conducted for two crop years (1977–79) at the Indian Agricultural Research Institute, New Delhi. The double cropping system producing 8×103 kg/ha/yr grain (4.5×103 kg rice and 3.5×103 kg wheat) removed 166 kg N, 35 kg P and 174 kg K per hectare per year. Thus the rice-wheat double cropping system heavily depletes the soils of their NPK content and calls for balanced fertilization for continued high production. NPK removal was higher when a 135-day duration rice variety was grown than when a 105-day duration variety was grown, because the former resulted in overall (rice + wheat) more grains and straw. Similarly grain and straw yield and NPK removal was more with transplanted rice than when sprouted rice seeds were sown on puddled seedbed; the latter method was in turn superior to direct drilling. Use of urea briquette, neem cake coated urea and sulphur coated urea gave higher yields and resulted in removal of more NPK than prilled urea.
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    A numerical solution of whole plant nutrient uptake for soil-root systems with root hairs (1983)
    Springer
    Plant and soil 70 (1983), S. 403-413 
    Details
    ISSN: 1573-5036
    Keywords: Buffer power ; Diffusion ; Nutrient influx ; Phosphorus ; Root hair density ; Root hair length ; Soil solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Root hairs increase phosphorus, P, uptake over that due to the plant root alone. A mechanistic model using 16 parameters was developed to describe this process. The model was verified with an experiment using six species that varied widely in root hair length, density and radius. A sensitivity analysis was conducted and the results are included to illustrate the situations where root hairs contribute significantly to P uptake. Length of root hair, root hair density and root hair radius all influenced predicted P uptake with root hair length being particularily significant.
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    Phosphorus absorption (32P) by apple trees under drip irrigation as influenced by the physical properties of the soil (1983)
    Springer
    Plant and soil 71 (1983), S. 381-385 
    Details
    ISSN: 1573-5036
    Keywords: Apple tree ; Drip irrigation ; Phosphorus ; Soil physical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary P absorption by apple tree roots (Golden delicious/M2) is studied using carrier-free32P. A qualitative model of the influence of some physical properties of the soil is proposed combining individual tree responses to32P injection.
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    URL: http://dx.doi.org/10.1007/BF02182679
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    Nitrogen nutrition, photosynthesis and carbon allocation in ectomycorrhizal pine (1983)
    Springer
    Plant and soil 71 (1983), S. 415-431 
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    ISSN: 1573-5036
    Keywords: Carbon allocation ; Light Mycorrhizas ; Nitrogen ; Phosphorus ; Photosynthesis ; Pinus contorta ; Pinus taeda ; Pisolithus tinctorius ; Respiration ; Source-sink ; Suillus granulatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies examined net photosynthesis (Pn) and dry matter production of mycorrhizal and nonmycorrhizalPinus taeda at 6 intervals over a 10-month period. Pn rates of mycorrhizal plants were consistently greater than nonmycorrhizal plants, and at 10 months were 2.1-fold greater. Partitioning of current photosynthate was examined by pulse-labelling with14CO2 at each of the six time intervals. Mycorrhizal plants assimilated more14CO2, allocated a greater percentage of assimilated14C to the root systems, and lost a greater percentage of14C by root respiration than did nonmycorrhizal plants. At 10 months, the quantity of14CO2 respired by roots per unit root weight was 3.6-fold greater by mycorrhizal than nonmycorrhizal plants. Although the stimulation of photosynthesis and translocation of current photosynthate to the root system by mycorrhiza formation was consistent with the source-sink concept of sink demand, foliar N and P concentrations were also greater in mycorrhizal plants. Further studies examined Pn and dry matter production ofPinus contorta in response to various combinations of N fertilization (3, 62, 248 ppm), irradiance and mycorrhizal fungi inoculation. At 16 weeks of age, 6 weeks following inoculation with eitherPisolithus tinctorius orSuillus granulatus, Pn rates and biomass were significantly greater in mycorrhizal than nonmycorrhizal plants. Mycorrhizal plants had significantly greater foliar %P, but not %N, than did nonmycorrhizal plants. Fertilization with 62 ppm N resulted in greater mycorrhiza formation than either 3 or 248 ppm. Increased irradiance resulted in increased mycorrhiza formation.
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    The growth, activity and distribution of the fruit tree root system (1983)
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    Plant and soil 71 (1983), S. 23-35 
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    ISSN: 1573-5036
    Keywords: Apple ; Mycorrhizas ; Phosphorus ; Root activity ; Root growth ; Water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The paper reviews information, much of it obtained from studies using the East Malling root observation laboratories, on the growth and development of the fruit tree root system. The production of new white root varies from year-to-year, generally being highest in the early years. As trees age, woody roots constitute an increasing fraction of total root length although the contribution made by new root growth to the total root length of established trees is also affected by soil management, being higher for trees under grass than under herbicide. Soil management also affects the balance of short (lateral) to long (extension) roots; under grass there are more lateral roots. Calculation of the rate of water uptake per unit root length needed at various times in the year to meet transpirational demand, suggests that woody roots, which recent experimental work has shown to be capable of absorbing water, must be responsible for much of total water supply. Measurements of VA mycorrhizal infection in field-grown trees indicated, for part of the season, higher per cent infection in trees grown under irrigated grass than under herbicide management. It is suggested that this, which is associated with raised leaf phosphorus levels, may be due at least partly to higher numbers of lateral roots, the root type which becomes infected. The growth and functioning of the root system under field conditions depend upon the production and integration of a range of root types.
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    Phosphatase production by mycorrhizal fungi (1983)
    Springer
    Plant and soil 71 (1983), S. 455-462 
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    ISSN: 1573-5036
    Keywords: Birch ; Mycorrhizas ; Phosphorus ; Pine ; Saprophytes enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Sheathing mycorrhizal fungi have been shown to possess phosphatase enzymes which can hydrolyse inositol hexaphosphate. In a range of mycorrhizal fungi, this activity was often greater than in two common decomposer basidiomycetes. Mycorrhizal birch and pine roots both produce phosphatases. In birch production is inversely related to the inorganic phosphorus concentration in the growth medium. Mycorrhizas reduce phosphatase activity compared with non-mycorrhizal plants. Phosphatase production by basidiomycete fungi in liquid culture is independent of P in the medium. Saprophytic basidiomycetes tend to incorporate hydrolysed phosphate into their biomass. In contrast mycorrhizal fungi release more into solution than they absorb. The significance of this difference in relation to the supply of nutrients to plants is discussed.
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    The search for and interpretation of genetic controls that enhance plant growth under deficiency levels of a macronutrient (1983)
    Springer
    Plant and soil 72 (1983), S. 335-350 
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    ISSN: 1573-5036
    Keywords: Calcium ; Nutrient stress ; Phosphorus ; Potassium ; Root growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Techniques developed to measure growth of tomatoes and beans under limiting amounts of either P, K or Ca in solution culture reveal differences among strains. Genetic analysis permits estimates of gene action for control of efficiency and the isolation of improved segregants. The genetic isolates have value in studying mechanisms contributing to uptake, transport and utilization processes.
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    URL: http://dx.doi.org/10.1007/BF02181972
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    Effect of soil salinity on the electro-chemical and chemical kinetics of some plant nutrients in submerged soils (1983)
    Springer
    Plant and soil 75 (1983), S. 455-472 
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    ISSN: 1573-5036
    Keywords: Ammonification ; Eh ; Flooded soils ; Iron ; Manganese ; Nitrate reduction ; Phosphorus ; pH ; Salinity and extractable cations ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The electro-chemical and chemical kinetics of six California rice soils were significantly influenced by the presence of salts up to an EC of 9 mmhos/cm in saturation extract (ECe). Subsamples of each soil salinity treatment were incubated for periods up to 10 weeks after flooding. Most of the changes in Eh and pH values took place in the first 3–4 weeks after submergence. Salinity decreased pH values, but slightly increased the redox-potential. Both ammonification and nitrate reduction were significantly decreased, by increasing soil salinity. Salinity up to 9 mmhos/cm did not affect levels of Bray and Kurtz extractable P, but increased the water extractable Ca, Mg, K and Mn. In DTPA extract, salinity in incubated soils had no effect on Zn in 4 soils, but it decreased Fe in acid and neutral soils. Possible explanations for the electro-chemical and chemical kinetic changes due to flooding and salinity are discussed.
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    Ionic interactions in rice plants from dilute solutions (1983)
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    Plant and soil 70 (1983), S. 309-316 
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    ISSN: 1573-5036
    Keywords: Calcium ; Ionic interaction ; Magnesium ; Nutrient solution ; Oryza sativa L. ; Phosphorus ; Potassium ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ionic interactions may occur as cation-cation interactions, anion-anion interactions, or cation-anion interactions. Greater knowledge of this subject is warranted, due to the intensification of agriculture, in devising efficient fertilization systems. The present study was undertaken to elucidate the interaction among P, K, Ca and Mg absorption by the intact rice (Oryza sativa L.) plants from dilute solutions. The uptake of P was independent of Ca concentrations up-to 250 μM Ca but-there was a small decrease at the higher concentrations. Absorption of K and Mg was stimulated in the presence of Ca ions at low concentrations. But K and Mg absorption was decreased at higher Ca concentrations. Increasing concentrations of K in the nutrient solution depressed P and Ca uptake. Magnesium uptake was stimulated at lower concentrations of K, but at higher concentrations it was also decreased. Similarly, absorption of K and Ca was also decreased with increasing concentrations of Mg. Magnesium at lower concentrations stimulated P uptake but at higher concentraions it was decreased. In the present study maximum growth of rice plants was achieved at about 250μM Ca, 260 μM K, and 33μM Mg in the nutrient solution.
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    Relationship between P and Mn in chickpea (Cicer arietinum L.) (1983)
    Springer
    Plant and soil 72 (1983), S. 85-90 
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    ISSN: 1573-5036
    Keywords: Chickpea ; Manganese ; Phosphorus ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Phosphorus and Mn relationship was studied in chickpea at two stages of growth in pot culture using 0, 7.5, 15 and 30 ppm P and 0, 5, 10 and 15 ppm Mn. The dry matter yield increased with P at both stages of growth. Manganese improved the yield only in the first stage. Initial levels of Mn enhanced while higher levels had a depressing effect on tissue P. Addition of 7.5 ppm P enhanced Mn concentration at first stage and at higher levels a marked reduction in Mn content was observed at both the stages.
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    Plant genotype differences in the uptake, translocation, accumulation, and use of mineral elements required for plant growth (1983)
    Springer
    Plant and soil 72 (1983), S. 175-196 
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    ISSN: 1573-5036
    Keywords: Boron ; Calcium ; Copper ; Genotypic differences ; Iron ; Magnesium ; Manganese ; Mineral nutrition ; Molybdenum ; Nitrogen ; Phosphorus ; Plant adaptation ; Plant breeding ; Potassium ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant genotypes differ in their uptake, translocation, accumulation, and use of mineral elements. Examples of genotype differences to iron, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, boron, copper, zinc, and molybdenum are discussed. Current knowledge is sufficient to indicate that many crop plants can be improved for the efficient use of mineral elements and better adaptation to mineral stress conditions.
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    Nutrient inflows into apple roots (1983)
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    Plant and soil 71 (1983), S. 371-380 
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    ISSN: 1573-5036
    Keywords: Apple ; Calcium ; Copper ; Iron ; Irradiance ; Magnesium ; Manganese ; Nitrogen ; Nutrient uptake rate ; Phosphorus ; Potassium ; Scion effects ; Season ; Source of nitrogen ; Temperature ; Tissue nutrient level ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The rates of uptake of nutrients from solution by apple roots were measured (a) in a root laboratory, using intact roots of mature trees growing under field conditions and (b) in controlled environment using young trees. Maximum nitrate inflows into Discovery/M.9 roots under field conditions were only slightly lower than those into roots of the same genotype in controlled environment, but up to 80 times lower than those into roots of Worcester Pearmain seedlings. At any given external P concentration, P inflows into roots of field-grown trees were about 2.5-times lower than those into the roots of young trees in controlled environment. Nitrate inflows were constant above a solution concentration of 20 mmol m−3 in both field-grown and small trees. In both cases, phosphate inflows increased linearly with solution concentration up to 10 mmol m−3. Among the various plant and environmental factors influencing nutrient uptake characteristics of apple roots were: the scion genotype, tissue nutrient levels, root origin, the form in which N is supplied, level of irradiance of the shoot, root temperature and the season of the year. The effects of these factors are illustrated with examples.
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    Rationale of selection for specific nutritional characters in crop improvement withPhaseolus vulgaris L. as a case study (1983)
    Springer
    Plant and soil 72 (1983), S. 351-364 
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    ISSN: 1573-5036
    Keywords: Acid soils ; Cation exchange capacity ; Fertilizer use ; Nitrogen ; Phaseolus vulgaris ; Phosphorus ; Selection ; Soil stresses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Genetic effects are obtainable for any aspect of transport, accumulation, and efficiency of nutrient use by plants, and for virtually any element. Some of the important characters are: tolerance to acid soils (18% of soils or 2.4 billion ha), tolerance to high pH induced Fe-chlorosis, and tolerance to salinity (about 1,000 m ha). Genotypes which made better use of N and P would be the means of saving fertilizers, especially important to developing countries. A 10% economy of fertilizer use represents a minimum world saving of US$6 billion annually. Phaseolus vulgaris is taken as a model to show that although we know quite a lot about the extent of its nutritional variation, e.g. adaptability to acid soils, and the crop's utilization of N and P, we are handicapped in exploiting this because of lack of genetic information. This in turn depends on knowledge of specific mechanisms, and investigating these must be a priority.
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    Efficiency of nitrogen, phosphorus, and potassium use by corn, sunflower, and sugarbeet for the synthesis of organic matter (1983)
    Springer
    Plant and soil 72 (1983), S. 219-223 
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    ISSN: 1573-5036
    Keywords: Corn ; Nitrogen ; Phosphorus ; Potassium ; Sugarbeet ; Sunflower
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A three-year experiment was conducted in natural conditions on chernozem soil to examine the efficiency of nitrogen, phosphorus, and potassium use by corn (C4 type), sunflower and sugarbeet (C3 type) grown in optimum conditions of mineral nutrition (N100P100K100 kg/ha). Plant materials were analysed for the concentration of nitrogen, phosphorus, and potassium and dry matter mass per individual plant parts and the whole plant. Leaves of different age, of all three plant species, were analysed to find eventual differences in the efficiency of use of nitrogen, phosphorus, and potassium in the synthesis of organic matter depending on leaf age. It was found that corn had the lowest concentration of the elements studied but the highest dry matter mass. In other words, corn was more efficient than sunflower or sugarbeet in the use of these elements for the synthesis of an organic matter unit. Such results were arrived at in both sets of analyses, i.e., the analyses of leaves performed in the course of ontogenetic plant development as well as the analyses of leaves of different age.
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    Efficiency and kinetics of phosphorus uptake from soil by various barley genotypes (1983)
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    Plant and soil 72 (1983), S. 225-230 
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    ISSN: 1573-5036
    Keywords: Barley ; Kinetic parameters ; Phosphorus ; Varietal effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Barley cultivars grown under field conditions of moderate deficiency of phosphorus (P) had great differences in P uptake and grain yields. As the rate determining step in P uptake under these conditions is located in the root net influx of P (ĪnL*) per g of dry matter of the plant can be expressed by $$\bar I_n L^* = \bar I_{max} L^* \frac{{c - c_{min} }}{{c - c_{min} + K_m }}$$ where Īn, L*, Īmax, c, cmin and Km denote mean net influx per unit length of the root, root length per unit weight of the plant, maximal mean net influx per unit length of the root, P concentration at the root surface, minimum concentration in solution of which net influx appears to be zero and Michaelis-Menten factor of P uptake, respectively. Studies of P uptake kinetics in water culture showed that the values of L*, Īmax, Km and cmin of P uptake varied considerably between barley cultivars. Furthermore, agreement was found between P uptake in the field and P uptake predicted from Īmax-, Km-, cmin- and L*-values observed in water culture experiments. The data thus indicate that it should be possible to improve the efficiency by which plants utilize soil as a source of P by selecting and/or developing genotypes of barley with a smaller cmin and/or Km and a greater Īmax and/or L* during the main period of growth. The results suggest therefore that it should be feasible to adapt plants to a considerably lower soil P level.
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    Plant and soil factors including mycorrhizal infection causing sigmoidal response of plants to applied phosphorus (1983)
    Springer
    Plant and soil 73 (1983), S. 187-201 
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    ISSN: 1573-5036
    Keywords: Glomus fasciculatum ; Iron hydroxide ; Lolium rigidum ; Phosphorus ; Response equation ; Ryegrass ; Sigmoidal response ; Subsoil ; Subterranean clover ; Trifolium subterraneum ; Vesicular arbuscular mycorrhiza
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In a series of glasshouse experiments, plants were grown in pots and their response to applied phosphate was measured. In the experiments we measured the response of subterranean clover and ryegrass to applied phosphate in surface soil and subsoil, with and without inoculation with vesicular-arbuscular (VA) mycorrhizal fungi, and with different levels of added iron hydroxide. For subterranean clover, there was often a clearly marked threshold level of phosphate application below which the plants took up little P and grew poorly. This threshold effect led to the sigmoidal response curves. It occurred when plants were grown in subsoil and in surface soil when iron hydroxide was added. However, it only occurred when the plants were non-mycorrhizal. Inoculation with a VA mycorrhizal fungi (Glomus fasciculatum) eliminated the threshold even when large amounts of iron hydroxide were present. For ryegrass, no threshold was observed and the response curve was never sigmoidal. Thus sigmoidal response curves to applied phosphate were only observed when a coarse-rooted plant species (subterranean clover) was grown in soils with large adsorption capacities for phosphate, and when roots were not mycorrhizal. Sigmoidal response to applied phosphate may occur because there is a threshold concentration of P in soil solution for adsorption by plant roots, for movement to plant roots or for desorption of adsorbed phosphate from the soil particles.
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    The acquisition of phosphorus byLupinus albus L. (1983)
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    Plant and soil 70 (1983), S. 107-124 
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    ISSN: 1573-5036
    Keywords: Citrate ; Iron ; Lupins ; Lupinus albus L. ; Phosphorus ; Polymers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Large quantities of citrate ions have been shown to be secreted by the roots ofLupinus albus. It is postulated that these react in the soil to form ferric hydroxy phosphate polymers which diffuse to the root surface where they are degraded by the action of reducing agents in the presence of an Fe II uptake mechanism balanced by hydrogen ion secretion. Some known chemical behaviour of Fe III and citrate which supports this postulate is reviewed. Evidence is also presented which suggests that much of the Fe absorbed circulates within the root system and is subsequently precipitated.
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    Growth responses of several plant species to mycorrhizae in a soil of moderate P-fertility (1983)
    Springer
    Plant and soil 70 (1983), S. 199-209 
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    ISSN: 1573-5036
    Keywords: Endomycorrhizae ; Fumigation ; Methyl bromide ; Mycorrhizal dependency ; Phosphorus ; VAM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The growth of twenty plant species was compared under field conditions in a methyl bromide fumigated and non-fumigated soil. The non-fumigated soil had a wild endomycorrhizal flora and contained 100 μg/g of available phosphorus. No phosphorus was added to the soil but both fumigated and non-fumigated plots received a basal fertilization of 100 kg/ha N−NH4NO3 and 100 kg/ha K−KCl. Based on plant growth responses, three groups of plants were distinguishable. Plants from group I were mycorrhizal and had better growth in non-fumigated than in the fumigated soil. This group was the most important, including sixteen plant species. Stunting of plants from group I following soil fumigation was mainly attribuable to the destruction of mycorrhizae. Plants from group II (oat and wheat) grew equally well in non-fumigated and fumigated soils. For these plants which were mycorrhizal in the non-fumigated plots, the P-content of the soil was sufficient for growth and therefore no stunting was observed in the absence of mycorrhizae. Plants from group III (cabbage and garden beet) grew better in fumigated than in non-fumigated soil. Their better growth in fumigated soil was tentatively attributed to the destruction of soil-borne pathogens. They did not form mycorrhizae in non-fumigated soil. A new method of calculating mycorrhizal dependency is proposed, and the value calculated was named relative field mycorrhizal dependency (RFMD) index. It is also proposed that the acronym RFMD receive a superscript representing in μg/g the quantity of available P in the soil. Carrot with its characteristic root systems had the highest RFMD100 index (99.2%), but other plants with high phosphorus requirements for normal growth had a wide range of RFMD100 index values.
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    The acquisition of phosphorus byLupinus albus L. (1983)
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    Plant and soil 70 (1983), S. 391-402 
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    ISSN: 1573-5036
    Keywords: Intercropping Lupins ; Lupinus albus ; Manganese ; Nitrogen ; Phosphorus ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Significant interactions between wheat and lupins occur below ground and wheat intercropped with lupins has access to a larger pool of available P, Mn and N than has wheat grown in monoculture. This suggests that the wheat is able to take up nutrients produced or made available by lupins grown in association with it.
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    Growth responses of several plant species to mycorrhizae in a soil of moderate P-fertility (1983)
    Springer
    Plant and soil 70 (1983), S. 211-217 
    Details
    ISSN: 1573-5036
    Keywords: Endomycorrhizae ; Fumigation ; Methyl bromide ; Phosphorus ; VAM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A greenhouse experiment was carried out comparing the growth of various plant species in non-fumigated, fumigated, and fumigated-inoculated soils. The soil used contained numerous pieces of root of Broom-Corn Millet (Panicum miliaceum L.) that were found intensely colonized by indigenous endomycorrhizal fungi. The soil was fumigated with methyl bromide and the inoculum used was a mixture of VA mycorrhizal root fragment from plants grown in the field from which the soil was collected. Plants used were cabbage (Brassica oleracea L. var Copenhagen Market), carrot (Daucus carota L. var. Nantaise), leek (Allium porrum L. var. American Flag), marigold (Tagetes patulus L. var. Golden Boy), tomato (Lycopersicum esculentum Mill. var. Michigan Ohio), sweet corn (Zea mays L. var. Span Cross) and wheat (Triticum aestivum L. var. Glenlea). No phosphorus was added to the soil which contained 93 μg/g of available P (bray II). All plants tested formed mycorrhizae except cabbage. Generally, values of the root endomycorrhizal colonization (REC) index were higher in fumigated-inoculated soil than in non-fumigated soil. Cabbage grew equally well in fumigated and fumigated-inoculated soil, but better than in non-fumigated soil. Cabbage did not form VA mycorrhizae and its better growth in fumigated soil was tentatively attributed to the destruction of soil-borne pathogens and the absence of competition. Wheat grew equally well in the three treatments, because 93 μg/g of available P is sufficient for wheat growth and thus the mycorrhizae were not efficient. The five other plant species used were severely stunted in fumigated soil and the inoculation permitted the reestablishment of normal growth as in non-fumigated soil. Growth stimulation is attributed to the efficiency of VA mycorrhizae since these plants were mycorrhizal in non-fumigated soil and in fumigated-inoculated soil. Stunting of these plants in fumigated soil was due to the destruction of VA mycorrhizae since results show that this stunting cannot be attributed to methylbromide residues in the soil. Moreover soil pH and nutrient content were not markedly changed after fumigation.
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    Increased uptake of anions by plants with vesicular-arbuscular mycorrhizas (1983)
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    Plant and soil 71 (1983), S. 463-467 
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    ISSN: 1573-5036
    Keywords: Anion uptake ; Barley ; Hordeum vulgare ; Mycorrhiza ; Phosphorus ; pH Rhizosphere ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In two field experiments sown in 1982 to test the effect of vesicular-arbuscular mycorrhizas (VAM) on growth and phosphorus nutrition of (i) spring wheat and spring barley, (ii) winter wheat and winter barley, we measured the concentrations of the major cation (K+, Ca2+, Mg2+ and Na+) and anions (Cl−, SO4 2−, H2PO4 − and NO3 −) in shoot tissue. In all cases the sum of the anion concentrations (ΣA) was increased strongly by mycorrhizal infection but not by P additions, confirming earlier observations2 on spring wheat. The concentration of total cations (ΣA) was generally reduced by P additions, hence P and VAM both reduced the cation excess (ΣC−ΣA) but by different mechanisms. These results suggest that increased uptake of anions by plants with VAM may be a general phenomenom which would have important implications for the elemental composition of crops. The effect may also be manifested by other types of mycorrhizal association.
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    Genetic differences in phosphorus absorption among white clover populations (1983)
    Springer
    Plant and soil 72 (1983), S. 379-383 
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    ISSN: 1573-5036
    Keywords: Clover ; Phosphorus ; Populations ; Root ; Shoot ; Trifolium repens ; White clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight semi-natural white clover populations and two cultivars were grown in culture solutions containing 10 ppm and 0.01 ppm phosphorus (P). The rate of P uptake by the intact plants was then measured in solutions containing 10 ppm P. Phosphorus uptake per unit root length was twice as great by plants previously grown at 0.01 ppm P than those grown at 10 ppm P. Large differences in total P uptake were found among populations regardless of the pretreatment; most of this variation was accounted for by differences in root length. Only small differences were found between populations for P uptake per unit root length, and then only after pretreatment with 10 ppm P; this variation was largely accounted for by relative growth rate and shoot %P.
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    Individual culture and experimental population dynamics of Keratella cochlearis (Rotatoria) (1983)
    Springer
    Hydrobiologia 107 (1983), S. 35-45 
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    ISSN: 1573-5117
    Keywords: zooplankton ; rotifers ; laboratory culture ; life table ; population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new culture method for K. cochlearis has made it possible to study isolated animals and to investigate the population dynamics of this pelagic rotifer species. The duration of principal developmental stages diminishes continuously with temperature. Decreased survival was associated with a reduced duration of individual fecundity. The age distribution of the population shifted toward younger age intervals with higher temperatures. Growth rates had an optimum at 15°C; the population dynamics, while lower for K. cochlearis than for some other rotifers, were in good agreement with field data.
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    A method for the laboratory culture of the planktonic rotifer Keratella cochlearis (Gosse) (1983)
    Springer
    Hydrobiologia 107 (1983), S. 47-50 
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    ISSN: 1573-5117
    Keywords: rotifers ; laboratory culture ; defined medium ; Keratella cochlearis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Procedures for the continuous laboratory culture of Keratella cochlearis in a defined medium and upon an algal food are described. Culturing success appears to be a function of food availability as well as composition. This availability requirement is satisfied by the use of test tubes and inverted titration plate concavities as culture vessels. The satisfactory culture medium contains an ammonia compound as a nitrogen source.
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    Algal dynamics and nitrogen and phosphorus cycling in a cypress stand in the seasonally flooded Great Dismal Swamp (1983)
    Springer
    Hydrobiologia 106 (1983), S. 115-122 
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    ISSN: 1573-5117
    Keywords: cypress swamp ; nitrogen ; nutrient cycling ; periphytic algae ; phosphorus ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both periphytic and planktonic algae are found in areas of the seasonally flooded Great Dismal Swamp (Virginia, U.S.A.). The dynamics of these algae were studied in a cypress stand and the periphytic algae appeared to be important as nutrient conservers. Clear temporal patterns in phytoplankton dominance were also observed.
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    Some new and rare warmwater rotifers (1983)
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    Hydrobiologia 106 (1983), S. 107-114 
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    ISSN: 1573-5117
    Keywords: subtropical ; Monogononta ; California ; Florida ; Bahamas ; rotifers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two new rotifer species, Lecane (Monostyla) aliger n.sp. and Proales pugio n.sp. are described from the Bahama Islands, Florida and California, and their autecology outlined. Some other rare rotifers are discussed which also prefer subtropical conditions. They are: Epiphanes clavulata, Epiphanes brachionus spinosus, Lecane crepida and Proalides tentaculatus tentaculatus. The existence of subtropical rotifer associations is discussed and supported by ecological data.
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    The significance of mating processes for the genetics and for the formation of resting eggs in monogonont rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 181-190 
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    ISSN: 1573-5117
    Keywords: rotifers ; genetics ; brachionidae ; mating behaviour ; resting eggs ; literature review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Crossbreeding experiments with three geographically distinct strains (E, S, and L) of the rotifer Brachionus plicatilis have been carried out in an attempt to elucidate the apparent male sterility of strain L, which is unable to produce resting eggs. The 9 crossing possibilities of the three strains have been investigated in 27 experiments. The results refute the concept of male sterility. L-males copulate successfully with mictic as well as with amictic females of strains E and S. Fertilized amictic E and S females produce defective resting eggs, which have only one thin shell and, which disintegrate after deposition. L-females cannot, as a rule, be fertilized. Moreover, crosses between strain E and S are succesful only in one direction; the reciprocal crosses failed. To explain the present results a hypothesis is suggested that the thickness of the body wall of newborn females differs in the three strains, and between mictic and amictic individuals. A sequence of gradually increasing body wall thickness of all types of females involved, together with a comparably increasing penetration ability of the males of strain E, S, and L explains the success or failure of all crosses, including the unilateral cross E × S.
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    Phototaxis in monochromatic light and microspectrophotometry of the cerebral eye of the rotifer Brachionus calyciflorus (1983)
    Springer
    Hydrobiologia 104 (1983), S. 191-196 
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    ISSN: 1573-5117
    Keywords: rotifers ; Brachionus calyciflorus ; phototaxis ; sensory pigment ; accessory pigment ; microspectrophotometry ; absorption spectrum ; spectral sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The observed wavelength-dependent variations in the phototaxis of the rotifer Brachionus calyciflorus inform us only partially about the spectral characteristics of the sensory pigment of the eye, since these variations are also linked to the absorption spectrum of the accessory pigment(s). The absence of phototaxis between 420 nm and 500 nm is due to the lack of sensitivity of the sensory pigments at these wavelengths The absence of response between 650 nm and 700 nm is due to a drop in the absorbance of the accessory pigments, which consequently no longer play a screening role at these wavelengths The existence of oriented responses between 350 nm and 420 nm and between 500 nm and 650 nm, is due to the joint intervention of the two types of pigments at these wavelengths
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    Sensory receptors involved in the feeding behaviour of the rotifer Asplanchna brightwelli (1983)
    Springer
    Hydrobiologia 104 (1983), S. 203-212 
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    ISSN: 1573-5117
    Keywords: rotifers ; sensory receptor ; feeding behaviour ; scanning electron microscopy ; transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study of the anterior sensory receptors of male and female Asplanchna brightwelli by scanning electron microscopy reveals some important differences in the region surrounding the mouth. In the male, the ventrolateral sensory bristles, the pseudotrochus, the inner and the outer buccal tufts and the mastax receptors are absent. The oral receptors are reduced. Transmission electron microscopy of these receptors shows that they consist of ciliated sensory cells surrounded by epithelial supporting cells. The distal ends of the cilia of the mastax receptors are modified; the cilia of the other receptors differ only in their length and rootlet structure from the locomotor cilia of the cingulum. A consideration of the feeding behaviour of Asplanchna leads us to suppose that these sensory cilia function in mechanoreception and in chemoreception.
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    An experimental system for the automatic tracking and analysis of rotifer swimming behaviour (1983)
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    Hydrobiologia 104 (1983), S. 197-202 
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    ISSN: 1573-5117
    Keywords: rotifers ; automatic tracking ; analysis of swimming behaviour ; video recording ; computer programs ; speed of swimming ; rate of change of direction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An automatic tracking system for rotifer swimming movements is described. The x and y coordinates of the Center of gravity of the animal are stored in the computer memory every twelfth of a second. Computer programs were developed to analyze the data and to calculate the average and the standard deviation for the following parameters per unit of time: distance traveled, turning angles toward the right and toward the left, distance from the point of departure as the crow flies. Histograms are traced by the computer showing the distribution of these values, as well as their evolution with time. This experimental system is dependable. The first values which we obtained for the swimming speed of rotifers correspond well with those which are given in the literature. The other parameters had not been measured until now.
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    On temperature acclimation in an experimental population of Brachionus calyciflorus (1983)
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    Hydrobiologia 104 (1983), S. 225-227 
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    ISSN: 1573-5117
    Keywords: rotifers ; temperature change ; morphology ; Brachionus population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of parental culture temperature regime on population parameters of offspring was investigated. Fecundity and net reproduction are influenced by the temperature conditions of the previous generation.
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    The Rotatoria-Monogononta of the River Drava in Slovenia, Yugoslavia (1983)
    Springer
    Hydrobiologia 104 (1983), S. 229-230 
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    ISSN: 1573-5117
    Keywords: rotifers ; Monogononta ; distribution ; pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    Resting eggs in rotifers (1983)
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    Hydrobiologia 104 (1983), S. 213-224 
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    ISSN: 1573-5117
    Keywords: rotifers ; resting eggs ; dormancy ; hatching ; production ; morphology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biology of resting eggs of monogonont rotifers is reviewed, covering literature published since the last major review by Gilbert (1974). The topics examined include resting egg production, morphology and species specificity, hatching, and evolutionary significance. Four major determinants of resting egg production are identified: mictic female production, male activity and fertility, female susceptibility to fertilization, and fertilized female fecundity. Recent work in these four areas is discussed as well as resting egg production in natural populations. Resting egg morphology, particularly shell structure and internal organization, is compared among species. Recent reports on the control of resting egg hatching in the laboratory are examined and the importance of temperature, light, diet, and salinity is reviewed. Two hatching patterns are contrasted, the first where eggs hatch at regular intervals over extended periods and the second where hatching is synchronized to some environmental cue. A latent period after resting egg formation, during which no hatching occurs, is defined for several species. The adaptive features of resting eggs are outlined including their contribution to genetic variability through recombination, their provision for environmental escape by dormancy, and their colonizing function resulting from their ease of dispersal. The type of cue utilized to initiate mictic female production as well as the pattern of resting egg hatching is related to environmental predictability.
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    Ammonia nitrogen and inorganic phosphorus excretion by the planktonic rotifers (1983)
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    Hydrobiologia 104 (1983), S. 231-236 
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    ISSN: 1573-5117
    Keywords: rotifers ; phosphorus ; nitrogen ; excretion ; temperature ; body weight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two series of experiments were carried out to determine the relation of the rate of phosphorus and nitrogen excretion by the planktonic rotifers to ambient temperature and individual body weights of these animals. The following formulas describing this relation were obtained: EP=0.0154 W−1.27 e0.096T EN=0.0879 W−1.01 e0.088 T, where EP and EN denote the rate of P and N excretion, respectively, in µg · mg dry wt−1 · h−1, W is body weight in µg dry weight, and T is temperature in °C.
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    Comparative studies on the relationship between temperature and duration of embryonic development of rotifers (1983)
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    Hydrobiologia 104 (1983), S. 237-246 
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    ISSN: 1573-5117
    Keywords: rotifers ; embryonic development time ; temperature ; ecological significance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The embryonic development times of four planktonic rotifers from Neusiedlersee (Austria) (Rhinoglena fertöensis, Brachionus calyciflorus, Keratella quadrata and Polyarthra dolichoptera) were determined at constant temperatures ranging from 0.6 °C to 10.5 °C. Development times decreased with increasing temperatures. The curvilinear relationship between temperature and development time was described by Bělehrádek's equation. Data on embryonic development times of rotifers are summarized and regression equations for the temperature-duration of development relationship are presented. Adaptation to temperature is discussed in the context of the thermal history of the various species and populations.
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    Composition, dynamics and production of Rotatoria in the plankton of some lakes of the Danube Delta (1983)
    Springer
    Hydrobiologia 104 (1983), S. 247-257 
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    ISSN: 1573-5117
    Keywords: rotifers ; dynamics ; biomass ; production ; turnover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Rosu, Puiu and Porcu lakes from the Danube Delta are lacustrine ecosystems characterized by a particularly great variation of the biotic and abiotic factors. This variation causes the development of a zooplankton reduced from the point of view of number and biomass, but rich from the taxonomic point of view. Its monthly and annual fluctuations can hardly be correlated to the rest of the plankton fauna and microflora. Rotifer production is low, turnover at the level of plankton rotifers being relatively uniform and dependent on water temperature.
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    Vertical distribution and rotifer concentrations in the chemocline of meromictic lakes (1983)
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    Hydrobiologia 104 (1983), S. 259-267 
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    ISSN: 1573-5117
    Keywords: rotifers ; rotifer plates ; meromictic lakes ; chemoclines ; rotifer vertical distributions ; photosynthetic bacterial plates ; anaerobiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The vertical distribution of planktonic rotifers has been analysed in relation to season in several meromictic lakes; a coastal lagoon with sea-water intrusion and three dissolution lakes from two karstic systems. Two species, Filinia hofmanni and a form of Anuraeopsis fissa have been found to be more or less restricted to the chemocline or adjacent strata any time they occurred. Many species common in the upper water layers developed large populations near or in the chemocline and more strikingly in summer. Some species had two vertical maxima (one in the surface or the thermocline and another near the chemocline), while others successively shifted their maxima between the upper layers and the chemocline. It is hypothetized that these rotifers are either very versatile or are differentiated as ecotypes, one of them adapted to the chemocline environment. This distribution in a peculiar fluctuating, anoxic, H2S-rich environment poses questions about the biology of those rotifers which there develop extraordinary populations.
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    Changes in the relative abundance of Polyarthra vulgaris and P. dolichoptera, following the elimination of fish (1983)
    Springer
    Hydrobiologia 104 (1983), S. 269-273 
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    ISSN: 1573-5117
    Keywords: rotifers ; feeding ; diet ; competition ; niche displacement ; field experiment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two rotifers, Polyarthra vulgaris and P. dolichoptera may have different temperature and oxygen optima. In addition, they consume similar foods including Chryptomonadales and Crysomonadales. P. dolichoptera disappeared from the plankton after experimental elimination of fish from a small lake. The disappearance may have been caused by a change in temporal availability of suitable food species (e.g. crysomonads) during early spring. A lack of food during this period, when the water was still cold, may have influenced the competitive balance between the two Polyarthra species.
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    Seasonal abundance of psammon rotifers (1983)
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    Hydrobiologia 104 (1983), S. 275-278 
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    ISSN: 1573-5117
    Keywords: rotifers ; interstitial ; psammon ; distribution ; abundance dynamics ; ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Zonation and abundance dynamics of interstitial rotifers in a semilotic beach of the North Sea island of Sylt were studied in 1975/76. The 13 species investigated prefer the damp sand of the beach slope. The sand flat is only sparsely inhabited. Rotifers only live in oxygen-rich sands. Neither the black sulphite layer in the sand flat nor the groundwater in the beach slope is populated. The family Colurellidae prefers warm temperatures in mid-summer, the family Proalidae colder temperatures in spring and autumn. In contrast to these two families that can be found in different frequencies all year round, the family Dicranophoridae occurs only in the cold seasons and disappears in mid-summer. Possibilities of maintaining the life cycle during these months are discussed.
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    Biometric analysis of Brachionus plicatilis ecotypes from Spanish lagoons (1983)
    Springer
    Hydrobiologia 104 (1983), S. 279-291 
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    ISSN: 1573-5117
    Keywords: rotifers ; Brachionus plicatilis ; biometry ; ecotypes ; cyclomorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Univariate comparisons and several multivariate statistical analyses have been performed to study the morphometric variability of B. plicatilis. Both laboratory clones kept under constant conditions and natural populations from different Spanish lagoons and different times of the year have been compared. The results show that not only size, but also allometric coefficients are influenced by environmental factors. However, an important genetic component in the variation of shape and size has been visualized. A clear North-South ordination of the populations of the different lagoons and an important dispersion between their summer populations as well as great differences due to seasonal variation became apparent by the multivariate statistical analysis used.
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    Comparative analysis of plankton rotifer biomass in large Estonian lakes (1983)
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    Hydrobiologia 104 (1983), S. 293-296 
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    ISSN: 1573-5117
    Keywords: rotifers ; biomass ; dominating species ; relation to trophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The number and biomass of rotifers in large eutrophic lakes is small in winter, reaches a maximum in spring or summer and decreases to a winter minimum. The dynamics of rotifer participation as part of total zooplankton is opposite to their absolute number: the role of rotifers in zooplankton is great in winter, starts decreasing in spring, reaches a minimum in summer and increases again to its winter maximum. The number and biomass of rotifers is proportional to the trophy of the waterbody, but in the case of some species this correlation is inverse.
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    Empty loricas and the dynamics of Kellicottia longispina in a subalpine, oligotrophic lake (1983)
    Springer
    Hydrobiologia 104 (1983), S. 367-372 
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    ISSN: 1573-5117
    Keywords: rotifers ; Kellicottia longispina ; empty loricas ; Lake Tahoe ; Emerald Bay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The seasonal dynamics of Kellicottia longispina in Lake Tahoe and an isolated embayment of Lake Tahoe, Emerald Bay, were investigated for an 18-month period in 1977–79. Population birth and death rates were similar in the two systems, although productivity and Mysis relicta densities were higher in Emerald Bay. The timing of population changes was also similar. A major population increase in late winter 1978 was preceded by an increase in egg ratio; the subsequent spring decline of K. longispina was concurrent with decreased birth rates and increased death rates. Empty loricas of K. longispina were occasionally abundant in the plankton samples and seemed to result from K. longispina deaths when densities were high and when egg ratios were declining; it is possible that population senescence was responsible for the high densities of empty loricas observed. A potentially important predator, M. relicta, defecates K. longispina remains in compact fecal pellets; however, it is unlikely that the observed empty loricas resulted from Mysis-related deaths.
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    Utilization of cyanobacteria by Brachionus calyciflorus: Anabaena flos-aquae (NRC-44-1) as a sole or complementary food source (1983)
    Springer
    Hydrobiologia 104 (1983), S. 373-377 
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    ISSN: 1573-5117
    Keywords: rotifers ; Brachionus ; feeding ; population dynamics ; Anabaena
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rotifer Brachionus calyciflorus can utilize the cyanobacterium Anabaena flos-aquae as either a sole or supplementary food source in laboratory culture. Positive population growth rates accompany food densities of 10 or 100 µg dry weight ml−1, but slightly negative rates are found at a lower density (1.0 µg ml−1). These results are consistent for rotifers feeding on two strains of A. flos-aquae, UTEX-1444 and NRC-44-1, with slightly enhanced survivorship and reproduction with the latter food. A 1:1 mixture (by dry weight) of Euglena gracilis and A. flos-aquae (NRC-44-1) produces survivorship comparable to that of control rotifer cohorts fed E. gracilis alone, but elicits significantly greater fecundity and population growth rates than found with the control food suspension at the same biomass density.
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    Clearance rates of sessile rotifers: In situ determinations (1983)
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    Hydrobiologia 104 (1983), S. 379-383 
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    ISSN: 1573-5117
    Keywords: rotifers ; sessile rotifer ; feeding ; in situ ; clearance rate ; filtration rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Clearance rates of three sessile and four free-swimming rotifer species from a small acid bog-pond were measured using in situ techniques. Three radioactively labeled cell types, an alga (Chlamydomonas), a bacterium (Enterobacter = Aerobacter), and a yeast (Rhodotorula) were used as tracers. Clearance rates (using yeast) ranged from 〈1.0 to 〉250 µl · animal−1 · h−1 depending on species. Ptygura crystallina, Ptygura pilula, Floscularia conifera, and an unidentified bdelloid ingested all three foods with substantial variation in clearance rates among species and cell type. There was an insignificant error (〈0.3%) in clearance rate associated with non-ingestive uptake of radioactivity. Among the free-swimming taxa, Lecane sp. had a clearance rate of 〈0.5 µl · animal−1 · h−1 on yeast, while another Lecane sp. and Trichotria tetractis did not ingest that cell type.
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    Invertebrate predation on planktonic rotifers (1983)
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    Hydrobiologia 104 (1983), S. 385-396 
    Details
    ISSN: 1573-5117
    Keywords: rotifers ; invertebrate predation ; cyclopoid copepod
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Representatives from many taxa including the Protozoa, Cnidaria, Rotifera, Cladocera, Cyclopoida, Calanoida, Harpacticoida, Chaoboridae, and Mysidacea are reported to feed on rotifers. There are few good quantitative data on predation on rotifers by any of these taxa with two exceptions, Rotifera and Cyclopoida. The present review focuses on the dynamics of Cyclopoid copepod predation. Intense and selective cyclopoid copepod predation makes it an important factor to consider in studies of the population ecology and community structure of rotifer populations. Limited information available on other predatory invertebrate taxa suggests that rotifer production may contribute extensively to their diets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045996
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  • 96
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    Biogeography of rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 19-30 
    Details
    ISSN: 1573-5117
    Keywords: rotifers ; biogeography ; dispersal ; continental drift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biogeography of rotifers is discussed in light of general biogeographical concepts. It is argued that, in spite of considerable abilities for passive dispersal, vicariance can develop well in this group. Examples selected from the Branchionidae illustrate the high levels of endemicity found in Australia and South America, while the Indian subcontinent and Africa have a predominantly cosmopolitan fauna. An explanation for these patterns is found in drifting continents and Pleistocene climatic changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045948
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  • 97
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    Life histories of some species of Rotifera Bdelloidea (1983)
    Springer
    Hydrobiologia 104 (1983), S. 175-180 
    Details
    ISSN: 1573-5117
    Keywords: rotifers ; Bdelloidea ; life tables ; strategy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nine species of Rotifera Bdelloidea have been cultured under laboratory conditions. The species were collected from two different environments: one group from water courses, the other from terrestrial mosses. Life tables have been determined and population dynamics parameters have been calculated. The characteristics of the life history seem to be related to the natural environmental conditions of the species. The patterns of reproductive output may develop as adaptations to different selective pressures: species from unpredictable environments face the probability of leaving no young at all, while species from stable environments are less conservative in their energy budget. Life characteristics are discussed from the point of view of adaptive strategies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045965
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  • 98
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    Notes on the rotifers of coal mine water in Eastern Poland (1983)
    Springer
    Hydrobiologia 104 (1983), S. 307-309 
    Details
    ISSN: 1573-5117
    Keywords: rotifers ; ecology ; coal mine water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The species composition and quantitative structure of the rotifer fauna was investigated in a reservoir containing coal mine water. Only nine mainly planktonic species of rotifers, were found. Two of these were dominating: Brachionus angularis and B. rubens. They are typical indicators of eutrophic waters. Chlorides and sulphates may have an influence on the occurrence and quantitative structure of rotifer assemblages in the investigated reservoir.
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    URL: http://dx.doi.org/10.1007/BF00045982
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  • 99
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    Algal bioassays and algal growth controlling factors in eutrophic shallow lakes (1983)
    Springer
    Hydrobiologia 100 (1983), S. 59-64 
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    ISSN: 1573-5117
    Keywords: bioassays in situ ; algal growth ; nitrogen ; phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bioassays with water of eutrophic Lake Tjeukemeer were carried out in the laboratory, and, in the lake itself, by placing plexiglass tubes (∅ 9 cm) firmly in the mud. In the laboratory nitrogen had a strong growth-promoting effect on the concentrations of chlorophyll a, N-cell and COD-cell. In the bioassays in situ nitrogen increased the concentration of chlorophyll a, but not those of cellular N and cellular COD. It is argued that chlorophyll a is not a good indicator for algal growth in bioassays and that the extrapolation of laboratory experiments — where nitrogen limited algal growth — to the field situation — where light limited algal growth — often leads to erroneous results, especially in shallow eutrophic lakes. The main reason is probably that in bioassays in the laboratory the nutrient supply — both from external loading and from sediments — is often different and that processes like denitrification occur in the lake, but not in the bioassays.
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    URL: http://dx.doi.org/10.1007/BF00027422
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  • 100
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    Phosphorus limitation in some tropical African lakes (1983)
    Springer
    Hydrobiologia 100 (1983), S. 101-112 
    Details
    ISSN: 1573-5117
    Keywords: nutrient limitation ; phosphorus ; nitrogen ; phytoplankton biomass ; tropical lakes ; Kenya
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two of three Kenyan lakes studied between November 1979 and October 1980 have very short 33PO4 turnover times, indicating a high phosphorus (P) demand throughout the year. The P turnover time in Lakes Oloidien and Sonachi is as rapid as in the most P deficient temperate zone lakes. The third lake, Lake Naivasha, has a lower overall P demand and a wide seasonal range, with lowest demand between November 1979 and February 1980 when a P deficiency was unlikely. On an annual basis the Lake Naivasha status is, however, not statistically different from that recorded during the summer in Lake Memphremagog, a generally P-limited temperate zone lake. Lake Naivasha and Lake Oloidien fit well to the line of best fit for the Dillon-Rigler relationship relating total phosphorus (TP) and chlorophyll a derived in temperate zone lakes. Thus, temperate zone models predicting aspects of lake behaviour on the basis of TP may also be applicable to these two tropical lakes. Saline lake Sonachi had not only a short P turnover time but also responded dramatically to the fertilization of enclosures with P. However, it does not fit the TP-chla or the total nitrogen-chla plots from the temperate zone. This suggests that, in this saline lake at least, much of the TP is unavailable to the algae, with some of it in a particulate form that is readily extracted with boiling water. The epilimnetic N:P ratios also characterize lakes Oloidien and Sonachi lakes as highly P deficient and lake Naivasha as more moderately P limited. A single set of measurements in Winam Gulf (Lake Victoria) also showed a rapid P turnover time and thus P limitation, but as in lake Sonachi much of the TP was in a non-algal particulate form. Occasional measurements in three other hypertrophic and saline lakes suggest them to be primarily light limited on the basis of their very high photosynthetic cover. These findings support the hypothesis of a primary P limitation for those lakes not light limited, and contradicts literature suggestions that nitrogen is the primary limiting element in tropical lakes.
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    URL: http://dx.doi.org/10.1007/BF00027425
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