ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Springer  (382)
  • Nature Publishing Group  (34)
  • Oxford University Press
  • 1965-1969  (252)
  • 1960-1964  (165)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 16 (1969), S. 27-38 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary The dispersion of preys carried byFormica polyctena workers along their tracks is the greater they have been discovered further from the ant hill. A hypothesis is put forward according to which such dispersion would be accounted for by the difficulties of the burdened ants to orient themselves with the olfactive and visual references they use normally. The same hypothesis permits to explain the results obtained here, in detour experiments and elsewhere, in the statistical analysis of prey carrying speed.
    Notes: Résumé La dispersion des proies transportées par les ouvrières deFormica polyctena le long de leurs pistes est d'autant plus grande que ces proies ont été découvertes plus loin de la fourmilière. Une hypothèse est émise, suivant laquelle cette dispersion serait due aux difficultés qu'éprouveraient les fourmis chargées à s'orienter d'après les repères visuels et olfactifs qui leur servent d'habitude. Cette même hypothèse permet d'expliquer les résultats obtenus ici, dans des expériences de détour, et ailleurs, dans l'analyse statistique des vitesses de transport des proies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 13 (1966), S. 127-138 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Conclusions Il n'est pas impossible, en toute première approximation, d'assimiler une société d'insectes à un système multistable (Ashby) et les individus qui la composent à un ensemble d'organes de base (von Neuman). Ce sont là, en effet, deux façons de raisonner qui permettent de retrouver par la théorie de nombreauses formes de comportement observées dans la nature et, surtout, d'aborder de manières complémentaires l'important problème des interactions sociales et de la transmission de l'information entre insectes sociaux. Il est clair, à la lumière des travaux d'Ashby, qu'un certain bruit de fond est nécessaire à l'intérieur d'une société d'insectes, afin de réaliser l'indépendance relative des différents sous-systèmes, dont l'ensemble est susceptible de s'adapter, dans des délais convenables, à toute modification d'environnement. Quant aux théories devon Neuman, elles permettent de comprendre comment l'existence de ce bruit de fond, si elle est cause du caractère aléatoire et plus ou moins incorrect de la transmission de l'information, n'entrave pas pour autant le fonctionnement correct et fidèle de l'ensemble de la société. Il est, par ailleurs, curieux de constater que l'étude des systèmes cybernétiques auxquels nous nous sommes constamment référé ici,visait à l'origine la mise en évidence des analogies qu'ils présentent avec le cerveau. Or, si l'on veut bien admettre le bien-fondé des considérations développées dans cet article, il existe des rapports relativement étroits entre ces systèmes et ceux que constituent les insectes sociaux. Il semble, dès lors, que l'application de la cybernétique à l'étude des sociétés d'insectes constitue une méthode d'investigation qui devrait se révéler fructueuse et conduire, en particulier, à un renouveau de la théorie du superorganisme.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 15 (1968), S. 359-374 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Preys (bees) placed by the experimenter on a track ofFormica polyctena have the more chances to be carried to the nest by the ants they have been laid closer to the ant nest.Chauvin's «captor» shows a limit performance estimated to 85%. The statistical analysis of transport of preys allowed us to isolate two factors «exploration plus dispersion of preys» and «proximity to the ant hill» (the detailed study of which is to be undertaken in the near future). We show also that the transport speed of each prey depends less from its weight and from its bulk than from the sum of both.
    Notes: Résumé Les proies placées par l'expérimentateur sur une piste deFormica polyctena ont d'autant plus de chances d'être récupérées par les fourmis qu'elles ont été déposées plus près de la fourmilière. Il en résulte que le capteur deChauvin présente un rendement limite, évalué à 85%. L'analyse statistique des différentes vitesses de transport des proies par les fourmis permet de mettre en évidence deux facteurs: «exploration plus dispersion des proies» et «proximité de la fourmilière» (dont l'étude détaillée sera entreprise prochainement). On montre aussi que la vitesse de transport de chaque proie dépend moins de son seul poids ou de son seul encombrement que de la somme de ces deux facteurs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Annalen 170 (1967), S. 45-66 
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Zeitschrift 82 (1963), S. 394-402 
    ISSN: 1432-1823
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Zeitschrift 78 (1962), S. 143-148 
    ISSN: 1432-1823
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Zeitschrift 74 (1960), S. 221-231 
    ISSN: 1432-1823
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. In the loops of primary spermatocyte nuclei actinomycin causes characteristic and reproducible disintegrations of the structural elements composing the loops. The alterations become visible for the first time about 6 hours after injection of actinomycin and reach a maximum after about 24–30 hours. 2. The structure of the nucleolus is also changed by actinomycin. It looses its cortical “ribosomal” layer and detaches from the nuclear membrane to which it is normally attached. 3. All structural damage of the loops and the nucleolus caused by actinomycin is reversible. The regeneration of the loops starts approximately 40 hours after injection and is completed after about 100–120 hours. 4. In males with two Y chromosomes which form loops of different morphology because of genetical differences the actinomycin effects similar alterations as in normal males. During the regeneration each Y chromosome autonomously determines its specific type of loops. 5. The results are in good agreement with our hypothesis that the loops are modifications of the chromosome structure at sites of active genes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Examination of living spermatid nuclei of Gryllus domesticus has revealed the presence of the same structures, the X chromosome, the round body and the axial core structures, which have been described from electron microscopic observations. The outer ribbons of the axial core structures and the round body are composed of 100 Å fibres indiscernible from and often continuous with the fibres composing the X chromosome. That the outer ribbons of the axial core structures and the round body are chromosomal is further substantiated by the results of cytochemical examinations of formaldehyde fixed material which show that the axial core structures and the round body contain RNA, DNA and basic protein. Neither acetic acid-ethanol nor cold ethanol fixation preserve the round body and the axial core structures suggesting that a protein may be responsible for maintenance of the central core structure. The central core structures are always found in close association with condensed chromatin in regions where the chromosome elements are about 1000 Å apart, suggesting that the relative state of condensation of the chromatin and the spacial relationship between condensed regions may be two of the chief factors concerned in central core formation. Maintainance of the condensed state of the chromatin, however, may in turn depend upon central core integrity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...