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  • 1
    Digitale Medien
    Digitale Medien
    Instrumentation for biomagnetism (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 123-141 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455917
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455918
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  • 3
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455921
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  • 4
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455938
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  • 5
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455924
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  • 6
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455919
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  • 7
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455920
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  • 8
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455922
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  • 9
    Digitale Medien
    Digitale Medien
    A portable biomagnetic measuring system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 224-230 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455926
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  • 10
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455933
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  • 11
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455954
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  • 12
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455955
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  • 13
    Digitale Medien
    Digitale Medien
    The inverse problem in magnetopneumography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 594-607 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455957
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  • 14
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455958
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  • 15
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455959
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  • 16
    Digitale Medien
    Digitale Medien
    Magnetic-susceptibility plethysmography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 624-641 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455960
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  • 17
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455961
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  • 18
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455962
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455923
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455928
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  • 21
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455930
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  • 22
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455927
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  • 23
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455931
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  • 24
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455934
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  • 25
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455935
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  • 26
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455936
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  • 27
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455937
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  • 28
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455939
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  • 29
    Digitale Medien
    Digitale Medien
    Inferences concerning anatomy and physiology of the human brain based on its magnetic field (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 379-409 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetic (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: Riassunto Si riesaminano le ricerche sul campo magnetico indotto compiute negli ultimi due anni. Questi studi hanno mostrato che la tecnica magnetica si puó usare 1) per rivelare aspetti complementari delle fonti di corrente comuni al potenziale indotto, 2) per identificare l’organizzazione della corteccia cerebrale e delle arce subcorticali e 3) per misurare le proprietà funzionali delle aree neurali attive le cui posizioni sono identificate.
    Notizen: Summary Research in the evoked magnetic field reported in the last two years is reviewed. The studies have shown that the magnetic technique may be used 1) to reveal complementary aspects of the current sources common to evoked potential, 2) to identify the organization of the cerebral cortex and subcortical areas of the brain and 3) to measure functional properties of the active neural areas whose locations are identified.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455940
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  • 30
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455941
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  • 31
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455942
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  • 32
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455943
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  • 33
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455944
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  • 34
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455946
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  • 35
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455945
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  • 36
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455947
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  • 37
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455948
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  • 38
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455949
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  • 39
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455952
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  • 40
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455925
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  • 41
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455929
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  • 42
    Digitale Medien
    Digitale Medien
    High-resolution isofield mapping in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 291-300 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455932
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  • 43
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455950
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  • 44
    Digitale Medien
    Digitale Medien
    Clinical magnetoencephalography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 517-537 
    Details
    ISSN: 0392-6737
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455951
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  • 45
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02455953
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  • 46
    Digitale Medien
    Digitale Medien
    Rotifers as indicators of water quality (1983)
    Springer
    Hydrobiologia 100 (1983), S. 169-201 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; saprobity ; saprobic valence ; indicative weight of species ; saprobic index ; pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027429
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  • 47
    Digitale Medien
    Digitale Medien
    Individual culture and experimental population dynamics of Keratella cochlearis (Rotatoria) (1983)
    Springer
    Hydrobiologia 107 (1983), S. 35-45 
    Details
    ISSN: 1573-5117
    Schlagwort(e): zooplankton ; rotifers ; laboratory culture ; life table ; population dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00126701
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  • 48
    Digitale Medien
    Digitale Medien
    A method for the laboratory culture of the planktonic rotifer Keratella cochlearis (Gosse) (1983)
    Springer
    Hydrobiologia 107 (1983), S. 47-50 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; laboratory culture ; defined medium ; Keratella cochlearis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00126702
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  • 49
    Digitale Medien
    Digitale Medien
    Some new and rare warmwater rotifers (1983)
    Springer
    Hydrobiologia 106 (1983), S. 107-114 
    Details
    ISSN: 1573-5117
    Schlagwort(e): subtropical ; Monogononta ; California ; Florida ; Bahamas ; rotifers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00006742
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  • 50
    Digitale Medien
    Digitale Medien
    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 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; genetics ; brachionidae ; mating behaviour ; resting eggs ; literature review
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045966
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  • 51
    Digitale Medien
    Digitale Medien
    Phototaxis in monochromatic light and microspectrophotometry of the cerebral eye of the rotifer Brachionus calyciflorus (1983)
    Springer
    Hydrobiologia 104 (1983), S. 191-196 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Brachionus calyciflorus ; phototaxis ; sensory pigment ; accessory pigment ; microspectrophotometry ; absorption spectrum ; spectral sensitivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045967
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  • 52
    Digitale Medien
    Digitale Medien
    Sensory receptors involved in the feeding behaviour of the rotifer Asplanchna brightwelli (1983)
    Springer
    Hydrobiologia 104 (1983), S. 203-212 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; sensory receptor ; feeding behaviour ; scanning electron microscopy ; transmission electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045969
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  • 53
    Digitale Medien
    Digitale Medien
    An experimental system for the automatic tracking and analysis of rotifer swimming behaviour (1983)
    Springer
    Hydrobiologia 104 (1983), S. 197-202 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; automatic tracking ; analysis of swimming behaviour ; video recording ; computer programs ; speed of swimming ; rate of change of direction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045968
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  • 54
    Digitale Medien
    Digitale Medien
    On temperature acclimation in an experimental population of Brachionus calyciflorus (1983)
    Springer
    Hydrobiologia 104 (1983), S. 225-227 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; temperature change ; morphology ; Brachionus population dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045971
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  • 55
    Digitale Medien
    Digitale Medien
    The Rotatoria-Monogononta of the River Drava in Slovenia, Yugoslavia (1983)
    Springer
    Hydrobiologia 104 (1983), S. 229-230 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Monogononta ; distribution ; pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045972
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  • 56
    Digitale Medien
    Digitale Medien
    Resting eggs in rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 213-224 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; resting eggs ; dormancy ; hatching ; production ; morphology ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045970
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  • 57
    Digitale Medien
    Digitale Medien
    Ammonia nitrogen and inorganic phosphorus excretion by the planktonic rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 231-236 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; phosphorus ; nitrogen ; excretion ; temperature ; body weight
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045973
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  • 58
    Digitale Medien
    Digitale Medien
    Comparative studies on the relationship between temperature and duration of embryonic development of rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 237-246 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; embryonic development time ; temperature ; ecological significance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045974
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  • 59
    Digitale Medien
    Digitale Medien
    Composition, dynamics and production of Rotatoria in the plankton of some lakes of the Danube Delta (1983)
    Springer
    Hydrobiologia 104 (1983), S. 247-257 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; dynamics ; biomass ; production ; turnover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045975
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  • 60
    Digitale Medien
    Digitale Medien
    Vertical distribution and rotifer concentrations in the chemocline of meromictic lakes (1983)
    Springer
    Hydrobiologia 104 (1983), S. 259-267 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; rotifer plates ; meromictic lakes ; chemoclines ; rotifer vertical distributions ; photosynthetic bacterial plates ; anaerobiosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045976
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  • 61
    Digitale Medien
    Digitale Medien
    Changes in the relative abundance of Polyarthra vulgaris and P. dolichoptera, following the elimination of fish (1983)
    Springer
    Hydrobiologia 104 (1983), S. 269-273 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; feeding ; diet ; competition ; niche displacement ; field experiment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045977
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  • 62
    Digitale Medien
    Digitale Medien
    Seasonal abundance of psammon rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 275-278 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; interstitial ; psammon ; distribution ; abundance dynamics ; ecology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045978
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  • 63
    Digitale Medien
    Digitale Medien
    Biometric analysis of Brachionus plicatilis ecotypes from Spanish lagoons (1983)
    Springer
    Hydrobiologia 104 (1983), S. 279-291 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Brachionus plicatilis ; biometry ; ecotypes ; cyclomorphosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045979
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  • 64
    Digitale Medien
    Digitale Medien
    Comparative analysis of plankton rotifer biomass in large Estonian lakes (1983)
    Springer
    Hydrobiologia 104 (1983), S. 293-296 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; biomass ; dominating species ; relation to trophy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045980
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  • 65
    Digitale Medien
    Digitale Medien
    Empty loricas and the dynamics of Kellicottia longispina in a subalpine, oligotrophic lake (1983)
    Springer
    Hydrobiologia 104 (1983), S. 367-372 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Kellicottia longispina ; empty loricas ; Lake Tahoe ; Emerald Bay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045993
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  • 66
    Digitale Medien
    Digitale Medien
    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 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Brachionus ; feeding ; population dynamics ; Anabaena
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045994
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  • 67
    Digitale Medien
    Digitale Medien
    Clearance rates of sessile rotifers: In situ determinations (1983)
    Springer
    Hydrobiologia 104 (1983), S. 379-383 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; sessile rotifer ; feeding ; in situ ; clearance rate ; filtration rate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045995
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  • 68
    Digitale Medien
    Digitale Medien
    Invertebrate predation on planktonic rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 385-396 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; invertebrate predation ; cyclopoid copepod
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045996
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  • 69
    Digitale Medien
    Digitale Medien
    Biogeography of rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 19-30 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; biogeography ; dispersal ; continental drift
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045948
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  • 70
    Digitale Medien
    Digitale Medien
    Life histories of some species of Rotifera Bdelloidea (1983)
    Springer
    Hydrobiologia 104 (1983), S. 175-180 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Bdelloidea ; life tables ; strategy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045965
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  • 71
    Digitale Medien
    Digitale Medien
    Notes on the rotifers of coal mine water in Eastern Poland (1983)
    Springer
    Hydrobiologia 104 (1983), S. 307-309 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; ecology ; coal mine water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045982
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  • 72
    Digitale Medien
    Digitale Medien
    The Indian species of the genus Brachionus (Eurotatoria: Monogononta: Brachionidae) (1983)
    Springer
    Hydrobiologia 104 (1983), S. 31-39 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Brachionus ; India ; biogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The different species and infraspecific categories of the genus Brachionus, so far reported or described from India, are reviewed. Their distribution and taxonomic validity are discussed. Remarks are made on the ecology and epizoic nature of various species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045949
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  • 73
    Digitale Medien
    Digitale Medien
    Rotifers of the Antarctic and Subantarctic (1983)
    Springer
    Hydrobiologia 104 (1983), S. 57-60 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Antarctic ; zoogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An assessment of the distribution of rotifers in the Antarctic and Subantarctic is attempted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045952
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  • 74
    Digitale Medien
    Digitale Medien
    Rotifera from northeastern Quebec, Newfoundland and Labrador, Canada (1983)
    Springer
    Hydrobiologia 104 (1983), S. 49-56 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Labrador and Newfoundland ; additions to known fauna ; species composition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract One hundred and thirty-one species of rotifers, belonging to 40 genera, are reported from Newfoundland and Labrador, Canada. Of these, 101 are new records for the province and 21 are new records for Canada. Some species exhibited distinct differences from the original descriptions and are figured and discussed. Points of interest in species composition and distribution are noted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045951
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  • 75
    Digitale Medien
    Digitale Medien
    Rotifer communities of billabongs in northern and south-eastern Australia (1983)
    Springer
    Hydrobiologia 104 (1983), S. 41-47 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; diversity ; Australia ; tropical ; community
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Diversity and equitability of rotifer communities from billabongs (oxbows or cut-off meanders) in northern and southeastern Australia are compared. In both areas littoral taxa predominated in open water. Diversity values (Shannon-Wiener, H′) were higher than recorded for tropical assemblages elsewhere. Up to 80 rotifer species co-occurred in Northern Territory billabongs. Brachionids notably were absent; there was an apparent displacement of tropical assemblages into temperate Australia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045950
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  • 76
    Digitale Medien
    Digitale Medien
    Cryopreservation of monogonont rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 85-88 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; cryopreservation ; Brachionus plicatilis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Development of techniques to maintain viable rotifer clones in a frozen state would preserve the genotype and reduce routine maintenance for those clones not being actively studied. To this end we have frozen Brachionus plicatilis in dimethyl sulfoxide at concentrations ranging from 6% to 18%. Survival rates decreased as the endpoint temperature was reduced from −20 °C to −45 °C, but did not decrease when the temperature was further reduced to −196 °C (liquid nitrogen). Only 2% of the individuals survived freezing in liquid nitrogen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045956
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  • 77
    Digitale Medien
    Digitale Medien
    Production of the rotifer Brachionus plicatilis for aquaculture in Kuwait (1983)
    Springer
    Hydrobiologia 104 (1983), S. 77-84 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Brachionus plicatilis ; production ; aquaculture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Brachionus plicatilis were mass cultured using 10 M3,15 m3 and 20 m3 outdoor concrete tanks. Utilization efficiencies for different food combinations using marine yeast (Candida sp., MFD-Y-St.03), baker's yeast and Chlorella sp. for rotifer production were evaluated. With either marine yeast or baker's yeast, addition of Chlorella sp., at 0.5 m3 algal culture day−1 10 m−3 culture volume enhanced rotifer production. Under optimum conditions rotifer density was maintained at more than 450 individuals ml−1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045955
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  • 78
    Digitale Medien
    Digitale Medien
    Environmental factors affecting hatching of rotifer (Brachionus plicatilis) resting eggs (1983)
    Springer
    Hydrobiologia 104 (1983), S. 61-69 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; resting eggs ; hatching ; temperature ; salinity ; light ; algae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hatching experiments were carried out on a population of Brachionus plicatilis (Dor strain) resting eggs produced in batch laboratory cultures under controlled conditions and then stored for at least one month at 4 °C in the dark. Light was found to be obligatory for termination of dormancy. Over the temperature range of 10–30 °C (at 9.0‰ salinity), hatching was optimal (40–70%) at 10–15 °C and decreased linearly with the rise in incubation temperature. Resting eggs incubated over a salinity range of 9–40‰ (at 15 °C) showed optimal hatching at 16‰. Incubation of resting eggs in distilled water permitted normal embryonic development, but neonates died at eclosion. Presence of algae, Chlorella stigmatophora (0.5 × 106 cell ml−1), was found to aid hatching.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045953
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  • 79
    Digitale Medien
    Digitale Medien
    Continuous culture of the rotifer Brachionus plicatilis fed recycled algal diets (1983)
    Springer
    Hydrobiologia 104 (1983), S. 71-75 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; recycle ; culture-ecosystem ; Brachionus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A culture system for the rotifer Brachionus plicatilis was designed to maintain higher food conversion rates and stable population densities. Two 2001 plastic tanks were employed in the culture experiments, tank A for ‘feedback’ culture and tank B for a control culture. The experiments were carried out for 70 days at 24 °C, light intensity, 1500 lux, and a photoperiod of L:D 15:9. B. plicatilis were fed once a day on baker's yeast and Chlorella. Food conversion rates in tanks A and B were 24.7% and 10.1%, respectively. Population density of B. plicatilis in tank A was consistently stable at 100–150 ind. ml−1 throughout the culture period. Density in tank B, however, showed large fluctuations after 40 or 50 days and by the end of the experiment, declined to zero.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045954
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  • 80
    Digitale Medien
    Digitale Medien
    Some historical specimens of rotifers examined by scanning electron microscopy (1983)
    Springer
    Hydrobiologia 104 (1983), S. 131-134 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; scanning electron microscopy ; Floscularia ringens ; Asplanchna priodonta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Scanning electron micrographs have been prepared of two species of rotifer, Floscularia ringens (Linnaeus, 1758) and Asplanchna priodonta Gosse, 1850, from specimens stored in the collections of the British Museum (Natural History) for over seventy years. It is believed that these include the first scanning electron micrographs of a sessile rotifer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045958
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  • 81
    Digitale Medien
    Digitale Medien
    Aging in Brachionus plicatilis: The evolution of swimming as a function of age at two different calcium concentrations (1983)
    Springer
    Hydrobiologia 104 (1983), S. 141-146 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; aging ; Brachionus plicatilis ; swimming behaviour ; calcium ; automatic recording ; computer analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The swimming movements of young, middle-aged and old Brachionus plicatilis females, raised in calcium-sufficient and calcium-deficient culture media were recorded automatically. Computer analysis and statistical treatment of the results show that: 1) The middle-aged females swim faster than the young and the old females. In comparison to the middle-aged and the young, old females turn less often and nearly always toward the right, and they do not travel as far from their point of departure as the others 2) When the concentration of calcium in the medium is nearly zero, the swimming speed of middle-aged and old females is slower than that of middle-aged and old females raised in the presence of sufficient amounts of calcium
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045960
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  • 82
    Digitale Medien
    Digitale Medien
    A re-examination of the Lansing effect (1983)
    Springer
    Hydrobiologia 104 (1983), S. 135-139 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; aging ; Lansing Effect ; life history patterns
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Lansing Effect, simply stated, is that the offspring of old parents tend to have shorter lifespans than the offspring of young parents and in both cases these tendencies are transmitted to successive generations. This statement is difficult to justify from Lansing's data because of the variation in mean lifespan that was observed from one generation to the next. A more precise statement of the Lansing Effect is that isogenic lines derived from young parents tend to persist for more generations than lines derived from old parents. Lansing considered aging to be the result of a factor that was transmitted from mother to offspring via the eggs. He proposed that this factor influences longevity and also alters the pattern of reproduction. Members of short-lived lines derived from old parents reproduced earlier and at higher rates in succeeding generations. In contrast, members of long-lived lines derived from young parents delayed initial reproduction to later age classes in succeeding generations. These proposals are examined using a life table analysis of Lansing's data. The results suggest that the Lansing Effect in Philodina citrina is not due to aging, but rather is the direct result of the changes in fecundity patterns. Accordingly, it would seem prudent to regard the Lansing Effect with some skepticism until more is known about its physiological basis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045959
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  • 83
    Digitale Medien
    Digitale Medien
    Macromolecular synthesis during embryogenesis of Habrotrocha rosa Donner I. Replication of DNA (1983)
    Springer
    Hydrobiologia 104 (1983), S. 147-148 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; embryogenesis ; organogenesis ; DNA replication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract DNA synthesis was inhibited during embryogenesis of Habrotrocha rosa with mitomycin C and hydroxyurea. Inhibition of DNA replication in early stages of embryogenesis, at the beginning of organogenesis, just after cavitation of the stomodeum, resulted in a complete inhibition of further development. After this stage of embryogenesis development was insensitive to inhibition of DNA replication.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045961
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  • 84
    Digitale Medien
    Digitale Medien
    Behavior and ultrastructure of sensory organs in rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 89-129 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; mechanoreceptors ; chemoreceptors ; photoreceptors ; feeding behavior ; mating behavior ; analysis of trajects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Résumé 1. Cette revue présente l'état actuel de nos connaissances sur les comportements des Rotifères. II s'agit soit de réponses immédiates, reflexes, a des stimulus, soit de séquences codées dont le déclenchement et la succession sont a base sensorielle: comportement alimentaire, reproducteur, ou qui suit la ponte chez N. copeus ... La perception de stimulations lumineuses ou chimiques contrôle les caractéristiques de la nage (taxies, ortho- et clinocinèses). Chaque comportement spécifique d'un Rotifère correspond à des différenciations morphologiques spécifiques des organes effecteurs (formations tégumentaires, glandulaires, cils et muscles), mais également a des sensibilités qui varient d'une espèce a l'autre, et ne sont pas toujours connues précisément. 2. Cette revue présente également l'état de nos connaissance sur les récepteurs sensoriels des Rotifères. Leur structure et leur organisation sont très variables d'une espéce a une autre, présentant des différenciations ciliaires ou membranaires très originales, parfois uniques dans le règne animal. Chaque récepteur sensoriel est constitué des terminaisons d'un à quelques neurones sensoriels. La localisation des organes sensoriels, et la spécialisation des structures sensorielles, permettent d'émettre des hypothèses quant a leur fonction dans la photo-, mécano-ou chimio-reception. 3. Au terme de ce double bilan, plusieurs questions demeurent: quels sont les récepteurs qui sont impliqués dans certaines sensibilités mises en evidence (vibro-réception par exemple, ou telle ou telle photo- ou chimio-réception)? Quelles sont les fonctions sensorielles précises de chaque récepteur décrit? Est-ce qu'à chaque structure sensorielle originale correspond une sensibilité originale? Par ailleurs, par leur faible taille, leur eutélie, leur paucicellularité (environ 1000 cellules dont 200 neurones), et leur isogénicité au sein de clones faciles à élever, les Rotiferes sont de bons modéles théoriques pour les neurobiologistes. Enfin, l'étude de ses sensibilités et de ses comportements est nécessaire pour comprendre l'écologie de chaque espèce, voire de chaque clone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045957
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  • 85
    Digitale Medien
    Digitale Medien
    Cholinergic neurotransmission in rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 149-153 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; acetylcholinesterase ; choline acetyltransferase ; neurotransmitter ; cholinergic ; histochemistry ; electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The presence of acetylcholinesterase and choline acetyltransferase, enzymes involved in acetylcholine metabolism, has been shown in twelve species of rotifers. Both enzymes have been visualized by histochemical staining in live animals, and acetylcholinesterase was also isolated by acrylamide gel electrophoresis. All the known ganglia of rotifers as well as some sensory nerve endings have been found to contain these enzymes. Preliminary experiments aimed at the detection of norepinephrine and tyrosinase, an enzyme involved in catecholamine metabolism, were unsuccessful.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045962
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  • 86
    Digitale Medien
    Digitale Medien
    Rotifer nutrition using supplemented monoxenic cultures (1983)
    Springer
    Hydrobiologia 104 (1983), S. 155-166 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; nutrition ; synxenic ; monoxenic ; axenic ; dl-tryptophan ; vitamin B12 ; thiamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The evolution of rotifer feeding/ nutritional studies is discussed together with their relevance to ecological observations. Aseptic conditions and initially synxenic cultures are regarded as a basis for nutritional work. The marine rotifer Encentrum linnhei requires the amino acid dl-tryptophan as a supplement to the food-alga Brachiomonas submarina. Observations on feeding rotifers in natural water samples, together with the morphology of their feeding mechanisms, show Encentrum to be an omnivore; a natural source of tryptophan is suggested. Vitamin B12 and thiamine requirements of Encentrum and Brachionus plicatilis are examined and evidence shown for the quantitative control of the former vitamin by the rotifer's food algae. Axenic cultivation of rotifers is discussed and restricted growth of Brachionus reported under such conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045963
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  • 87
    Digitale Medien
    Digitale Medien
    Control of sexuality in Asplanchna brightwelli: threshold levels of dietary tocopherol and modification of tocopherol response by exogenous and endogenous factors (1983)
    Springer
    Hydrobiologia 104 (1983), S. 167-173 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Asplanchna ; population dynamics ; resting egg ; sexuality ; tocopherol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ingestion of one prey rotifer containing about 0.02 pg tocopherol was sufficient to cause young amictic females to produce a high proportion of mictic daughters. Varying the concentration of emulsified tocopherol ol and the population density of amictic females suggested that mictic-female induction approached an all-or-nothing response at relatively high population densities and increased with population density only when population densities were very low. Amictic females hatching from resting eggs were less likely to produce mictic daughters than those hatching from parthenogenetic eggs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045964
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  • 88
    Digitale Medien
    Digitale Medien
    Morphological variation of Keratella cochlearis (Gosse) in Lake Biwa, Japan (1983)
    Springer
    Hydrobiologia 104 (1983), S. 297-305 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Keratella ; morphological variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The length of the lorica (LL) of Keratella cochlearis cochlearis and of K. cochlearis tecta and the length of posterior spine (PSL) of the latter morphotype were measured in the strongly eutrophic basin and also in the mesotrophic basin of Lake Biwa, Japan, from September to December, 1980. In the population from the mesotrophic basin, the individuals with longer PSL prevail and the tecta forms are extremely rare. The LL values of both morphotypes from one sample do not differ. In December the LL increased to 95 µm in both morphotypes from 80 µm observed in September, while the PSL values decreased abrubtly in both basins in the middle of this period. It is suggested that the observed increase of LL could be related to the thermic factor, i.e. a steady decrease of water temperature, and the changes of PSL are correlated with the increase of nannoplankton and detritus aggregates noted in November. In this month an increase in fecundity and in the total numbers of rotifers took place as well (Hillbricht-Ilkowska, in press).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045981
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  • 89
    Digitale Medien
    Digitale Medien
    Rotifera or rotatoria? (1983)
    Springer
    Hydrobiologia 104 (1983), S. 1-2 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Rotatoria ; nomenclatuur ; history
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045945
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  • 90
    Digitale Medien
    Digitale Medien
    Parallelism in the evolution of rotifers (1983)
    Springer
    Hydrobiologia 104 (1983), S. 3-7 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; parallelism ; evolution ; phylogeny
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Parallelism in the evolution of rotifers is revealed in the repeated appearance, reduction, consolidation or enlargement of common structures as well as by left-right handedness. A possible phylogenetic scheme of rotifer evolution is given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045946
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  • 91
    Digitale Medien
    Digitale Medien
    Rotifera from Western Australian wetlands with descriptions of two new species (1983)
    Springer
    Hydrobiologia 104 (1983), S. 9-17 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Western Australia ; ephemeral waters ; zoogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The rotifer fauna of 100 fresh and saline wetlands of southwest Western Australia is documented. A systematic list of 83 recorded taxa is given, with eleven new records for the continent and two new species (Brachionus pinneenaus n. sp. and Lecane boorali n. sp.) described and figured. Species assemblages are distinct from those of eastern Australia, with predominant taxa halophilous or indicative of ephemeral waters. Evolutionary and biogeographical relationships of the Western Australian rotifers are considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045947
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  • 92
    Digitale Medien
    Digitale Medien
    Rotifer occurrence in relation to water temperature in Loch Leven, Scotland (1983)
    Springer
    Hydrobiologia 104 (1983), S. 311-315 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; temperature ; Scotland ; occurrence ; grazing ; population dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Many rotifer species in Loch Leven show a distinct seasonality in occurrence. This appears to be primarily an effect of temperature. While some species seem to be eurythermal, other species show a well-defined range of temperature preference, outside which they are unable to maintain populations. Within this range, there is a close correlation between food availability and rotifer abundance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045983
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  • 93
    Digitale Medien
    Digitale Medien
    Substrate selection and larval settlement by Cupelopagis vorax (1983)
    Springer
    Hydrobiologia 104 (1983), S. 317-323 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Cupelopagis vorax ; sessile rotifers ; sexual reproduction ; substrate selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cupelopagis vorax was sampled for one year with a glass slide sampler. Slides were collected every two weeks and the numbers and locations of settled individuals noted. Reproductive condition of the collected rotifers was recorded. The population appeared suddenly and rapidly attained peak numbers. C. vorax shows a distinct preference for the underside of horizontally-oriented surfaces. Sexual reproduction occurred when the number of settling individuals was maximum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045984
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  • 94
    Digitale Medien
    Digitale Medien
    Changes in growth and size of Keratella cochlearis (Gosse) in relation to some environmental factors in cultures (1983)
    Springer
    Hydrobiologia 104 (1983), S. 325-328 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; Keratella cochlearis ; growth ; size ; culture ; food algae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Keratella cochlearis (Gosse) was cultured non-axenically in Carefoot medium diluted with Erken water at 5 °C, 15 °C and 20 °C with Rhodomonas minuta (Skuja) as a food alga. The rotifer reached ca. 120 ind. ml−1, having generation times of 2–7 days, a Q10-value of ca. 2, and at the lowest temperature 〉20% longer posterior spines. When co-cultured with Chlorella sp., at 0–30 mg Ca l−1 and 1.6 meq NaHCO3 l−1 in medium L 11 at 20 °C, the maximum generation time and individual numbers were 3–4 days and up to 100 ind. ml−1, respectively. Animal numbers increased in relation to nutrient multiples, up to two multiples, of the culture medium L 16. Growth and length were reduced, although the width increased above two multiples of this culture medium. The trace metal tolerance was broad and increased additions of a metal mixture (L 11) slightly increased the length of the rotifers. No major changes in the length were observed when HCO3 or Ca were varied in the culture medium (L 11), although a decrease in the length was noted in old cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045985
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  • 95
    Digitale Medien
    Digitale Medien
    Production of planktonic Rotatoria in Ormajärvi, an eutrophicated lake in southern Finland (1983)
    Springer
    Hydrobiologia 104 (1983), S. 329-333 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; zooplankton ; production ; Rotatoria ; P/B ratio ; eutrophication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The production of planktonic rotifers was studied in eutrophic Lake Ormajärvi. Of the total annual production of rotifers (2.9 g org. C m−2 or 231 mg dry weight m−3) 49% was achieved during one month (July) and 88% during 3 months of summer. The most important producers were Keratella cochlearis (1.2 g C m−2), Asplanchna priodonta (0.8 g C m−2) and Conochilus unicornis (0.6 g C m−2). The P/B ratio for the total rotifer community during the growing season (7 months) was 25.0; monthly P/ B values varied between 0.3 and 5.2. The daily P/ B values were highest among species of Collotheca. The relationships of rotifers to some biotic and abiotic factors (invertebrate predators — Mesocyclops, Cladocera, planktonic Protozoa and temperature) are briefly discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045986
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  • 96
    Digitale Medien
    Digitale Medien
    Annual dynamics and production of rotifers in an eutrophication gradient in the Baltic Sea (1983)
    Springer
    Hydrobiologia 104 (1983), S. 335-340 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; annual fluctuation ; eutrophication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Spatial and temporal fluctuations in rotifer abundance have been monitored along a trophic gradient in the northern Baltic. The most common rotifer was Synchaeta spp., which had one abundance peak in June and one in September–October. Only during the latter period was the abundance significantly higher in the eutrophic basin compared to the reference area. The annual production of Synchaeta spp. was about double in the eutrophic basin. A positive correlation between Synchaeta spp. biomass and phytoplankton biomass was obtained during the autumn, but not during the early summer peak, although the phytoplankton community was dominated by the same species. Keratella quadrata, K. cochlearis and K. cruciformis were most abundant in August–September, and all three species had increased abundance in the eutrophic basin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045987
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  • 97
    Digitale Medien
    Digitale Medien
    Abundance, dynamics and succession of planktonic rotifers in Lake Biel, Switzerland (1983)
    Springer
    Hydrobiologia 104 (1983), S. 349-352 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; abundance ; succession ; Synchaeta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Twenty species of planktonic rotifers were important in Lake Biel during 1978. Eight species were present throughout the year, four species occurred only in spring and eight species in summer or autumn. Rotifer numbers attained two major maxima, one in May (19.3 106 ind. m−2) and one in August (16.5 106 ind. m−2). Predominant genera were Synchaeta, Polyarthra, Conochilus, Asplanchna and Keratella. Within the genus Synchaeta a succession of different species was observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045989
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  • 98
    Digitale Medien
    Digitale Medien
    Community structure of planktonic rotifers in a mesotrophic lake (1983)
    Springer
    Hydrobiologia 104 (1983), S. 353-356 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; species diversity ; spatial overlap ; predation pressure ; Asplanchna herricki
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Seasonal changes of species diversity (Hr) and average spatial overlap (Ōjk) of planktonic rotifers in a mesotrophic lake were examined with respect to their dependence on habitat diversity (Hh) and on a predator (Asplanchna herricki). Hr was positively correlated with the density of A. herricki and with Hh. In the absence of A. herricki there was no correlation between Hr and Hh. Ōjk was negatively correlated with the density of A. herricki and with Hh; the correlation between Ōjk and Hh was independent of the presence of the predator.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045990
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Occurrence of Rotifera in the field under natural and intentionally-changed conditions (1983)
    Springer
    Hydrobiologia 104 (1983), S. 341-347 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; occurrences ; pools ; lake ; intentional ; change
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A comparison of population dynamics of rotifers under natural conditions with those under intentionally-changed ones was carried out at one Lake and five outdoor pools. In Lake Numasawa, dominant rotifers under natural conditions for the past two years were Polyarthra trigla vulgaris, Kellicottia longispina, Ploesoma truncatum, Asplanchna priodonta and Filinia longiseta. Keratella hiemalis, K. cochlearis, K. valga tropica, Brachionus caudatus and Ascomorpha saltans appeared sporadically. Three months after the start of circulation of part of the lake water by a water power plant no remarkable changes were observed as far as the seasonal and vertical distribution of dominant rotifers are concerned. In five pools with different kinds and ratios of covering by such macrophytes as Eichornia and Lemna or reed screen, three types of rotifer communities were found. Type I: Liliferotrocha sp., Brachionus calyciflorus, (B. budapestinensis), B. angularis, K. valga tropica, etc., in which both densities and frequencies were generally reduced in proportion to the ratio of covering either with macrophytes or reed screens. Type II: Filinia longiseta, Polyarthra trigla vulgaris, Asplanchnella sieboldi, etc. in which densities and frequencies were increased by covering either with macrophytes or reed screens. Type III: Trichocerca pusilla, B. quadridentatus, B. leydigi rotundus, Scaridium longicaudum, Euchlanis dilatata, Dicranophorus sp., etc, in which no precise correlation was found between occurrences of the Rotifers and ratio of covering.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045988
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Rotifers as indicators of lake types in Estonia (1983)
    Springer
    Hydrobiologia 104 (1983), S. 357-361 
    Details
    ISSN: 1573-5117
    Schlagwort(e): rotifers ; indicators of trophy ; indicators of lake types
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Data on the pelagic rotifer fauna in 10 Estonian lakes accumulated for 20 years, as well as published data are analysed. It is possible to distinguish three main indicator groups among rotifers: (1) for oligo- and mesotrophic lakes (Ploesoma hudsoni, Keratella serrulata, Synchaeta grandis, Asplanchna herricki, Ascomorpha ovalis, Gastropus stylifer, Conochilus hippocrepsis); (2) for meso-and eutrophic lakes (Trichocerca capucina, Filinia longiseta, F. limnetica, Keratella quadrata, K. cochlearis tecta, K.c. hispida, Polyarthra euryptera, Keratella hiemalis, Trichocerca porcellus, T. pusilla); (3) for eutrophic lakes (Brachionus spp., Anuraeopsis fissa, Pompholyx sulcata, P. complanata, Trichocerca cylindrica, Hexarthra mira).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00045991
    Standort Signatur Erwartet Verfügbarkeit
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    Artikel (Nationallizenzen)
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