Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Employment, schooling and productivity growth (1989)
    Springer
    De economist 137 (1989), S. 425-453 
    Details
    ISSN: 1572-9982
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Summary This paper presents an empirical analysis of labour demand and labour productivity growth in The Netherlands. Assuming an aggregate production function with as factors capital and 3 types of labour, distinguished by educational attainment, cost minimization leads to a set of 3 labour demand relations to be estimated on time series data. Using the estimates and the implied elasticities, aggregate labour productivity growth is decomposed into factor substitution, autonomous factors, labour time shortening, economies of scale, utilization rates and the increased educational level of the working population. The contributions of substitution, utilization rates and education appear to be substantial, notably in the seventies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01705974
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Enzyme-cytochemistry of the saccus dorsalis of the rainbow trout, Salmo gairdneri Richardson (1976)
    Springer
    Histochemistry and cell biology 48 (1976), S. 293-306 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the saccus dorsalis of the rainbow trout, Salmo gairdneri Richardson, the activity of various enzymes (transferase, lyases, oxidoreductases, hydrolases) have been studied in detail. The results of this enzyme-cytochemical study firmly demonstrate that the organ is metabolically highly active. The epithelial cells have a strong energy metabolism. Energy production can take place under aerobic as well as under anaerobic conditions. Evidence is presented that glucose from blood is directly utilized for energy demands. The epithelial cells show also high synthetic activities. The moderate amino acid metabolism may participate in the synthesis of an acid mucopolysaccharide-protein complex, especially in the so-called dark cells. Lipid metabolism appears to be restricted to the mitochondria, indicating a high turnover of lipid moieties in the membranes. In contrast to the normal looking mitochondria, the macromitochondria — besides shape and localization — have an extremely high lipid and monoamine metabolism, which may point to a special function in the cellular economy. The high activity of enzymes involved in the degradation of monoamines and in the hydration of CO2 is of particular physiological interest. The significance of the observations is discussed in relation to formerly obtained indications on the involvement of the saccus dorsalis in fluid secretion, extrusion of organic substances of low molecular weight into the ventricular system and uptake of organic substances from the cerebrospinal fluid. The hypothesis of the saccus dorsalis being an analogue of the choroid plexus is supported by several relevant data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00499246
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Coexistence for systems governed by difference equations of Lotka-Volterra type (1987)
    Springer
    Journal of mathematical biology 25 (1987), S. 553-570 
    Details
    ISSN: 1432-1416
    Keywords: Difference equations ; Lotka-Volterra equations ; Permanence ; Discrete semi-dynamical systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The question of the long term survival of species in models governed by Lotka-Volterra difference equations is considered. The criterion used is the biologically realistic one of permanence, that is populations with all initial values positive must eventually all become greater than some fixed positive number. We show that in spite of the complex dynamics associated even with the simplest of such systems, it is possible to obtain readily applicable criteria for permanence in a wide range of cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00276199
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The saccus dorsalis of the rainbow trout, Salmo gairdneri Richardson (1976)
    Springer
    Cell & tissue research 167 (1976), S. 467-491 
    Details
    ISSN: 1432-0878
    Keywords: Saccus dorsalis, Salmo gairdneri Richardson ; Histology ; Ultrastructure ; Cytochemistry ; Enzyme-cytochemistry ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The saccus dorsalis of the brain of the rainbow trout, Salmo gairdneri Richardson, has been investigated by means of histological, cytochemical, enzyme-cytochemical, electron microscopical and autoradiographical techniques. The saccus dorsalis is a rostro-dorsal evagination of the diencephalic roof, and consists of a partly folded epithelial wall separating the cerebrospinal fluid from the meningeal matrix fluid. The well-developed vascular system around the epithelial wall, consisting of capillaries with different diameters, seems to be part of the pineal vascular system. No structures were found that may be involved in a possible mechanical or nervous blood flow control. The single-layered epithelium consists of highly specialized cells of one specific type. These cells are mainly characterized by infolded basal membranes, long microvilli of a peculiar shape, non-folded lateral membranes bordering intercellular spaces, apical concentrations of elongate and cupshaped macromitochondria, a basally located rough endoplasmic reticulum, an apically situated smooth endoplasmic reticulum and apical concentrations of micropinocytotic vesicles. Morphological evidence is presented of a multiple function of these cells: (1) fluid secretion, (2) extrusion of low molecular weight organic substances into the ventricular system, (3) uptake of high molecular weight substances, and (4) uptake of low molecular weight organic substances (aminergic neurotransmitters [GABA]) from the cerebrospinal fluid. The significance of light and dark cells is discussed. Indications of a possible innervation of the saccus dorsalis epithelial cells were not observed. The functional significance of the saccus dorsalis (possible analogue of the choroid plexus?) is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215179
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The innervation of the corpus cardiacum of Locusta migratoria: A neuroanatomical study with the use of Lucifer yellow (1989)
    Springer
    Cell & tissue research 258 (1989), S. 301-308 
    Details
    ISSN: 1432-0878
    Keywords: Corpus cardiacum ; Neuroanatomical tracing ; Lucifer yellow ; Locusta migratoria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural connections of the corpus cardiacum (CC) in the African locust, Locusta migratoria, were labelled with the fluorescent tracer Lucifer yellow. (1) Unilateral anterograde labelling of the nervus corporis cardiaci I revealed fluorescent fibres in the storage lobe of the CC (CCS). Some fluorescent fibres in the CCS closely approached the ipsilateral border of the glandular lobes of the CC (CCG). Fluorescent fibres also projected into the neuropile of the hypocerebral ganglion via the ipsilateral nervi cardiostomatogastrici I and II, and from there into the oesophageal nerves. (2) Unilateral anterograde labelling of the nervus corporis cardiaci II revealed fluorescent fibres in the CCS and in the ipsilateral CCG. Fluorescent fibres also projected via the ipsilateral nervus corporis allati I into the corpus allatum. (3) Unilateral retrograde labelling of the nervus corporis allati I revealed a distinct fluorescent nerve tract that runs through the CCS and into the nervus corporis cardiaci II. The tract arises from about eight cell bodies in the brain at the rostroventral side of the ipsilateral calyx of the mushroom body. (4) Labelling of the recurrent nerve revealed fluorescent fibres and some fluorescent cell bodies in the hypocerebral ganglion and, via the nervi cardiostomatogastrici I and II, also in the CCS. Fluorescent fibres were also present in the oesophageal nerves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239450
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Further investigations on the structure and function of the saccus vasculosus of the rainbow trout, Salmo gairdneri Richardson (1978)
    Springer
    Cell & tissue research 187 (1978), S. 61-68 
    Details
    ISSN: 1432-0878
    Keywords: Saccus vasculosus (Salmo gairdneri Richardson) ; Alkaline phosphatase ; Ultrastructural cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Alkaline phosphatase activity in coronet cells of the saccus vasculosus of the rainbow trout was localized ultracytochemically. Deposits of reaction product were found in varying amounts on the membranes of primary vesicles in the globules. This observation is discussed in relation to other morphological data and the possible resorptive function of the coronet cells in the homeostasis of the CSF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220618
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ultrastructural enzyme-cytochemical study of the intrinsic glandular cells in the corpus cardiacum of Locusta migratoria: relation to the secretory and endocytotic pathways, and to the lysosomal system (1989)
    Springer
    Cell & tissue research 255 (1989), S. 167-178 
    Details
    ISSN: 1432-0878
    Keywords: Secretion ; Endocytosis ; Autophagy ; Corpus cardiacum ; Locusta migratoria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural aspects of the secretory and the endocytotic pathways and the lysosomal system of corpus cardiacum glandular cells (CCG cells) of migratory locusts were studied using morphological, marker enzyme, immunocytochemical and tracer techniques. It is concluded that (1) the distribution of marker enzymes of trans Golgi cisternae and trans Golgi network (TGN) in locust CCG cells corresponds to that in most non-stimulated vertebrate secretory cell types; (2) the acid phosphatase-positive TGN in CCG cells is involved in sorting and packaging of secretory material and lysosomal enzymes; (3) these latter substances are produced continuously; (4) at the same time, superfluous secretory granules and other “old” cell organelles are degraded; (5) the remarkable endocytotic activity in the cell bodies and the minor endocytotic activity in cell processes are coupled mainly to constitutive uptake of nutritional and/or regulatory (macro)molecules, rather than to exocytosis; (6) plasma membrane recycling occurs mainly by direct fusion of tubular endosomal structures with the plasma membrane and little traffic passes the Golgi/TGN; and (7) so-called cytosomes arise mainly from autophagocytotic vacuoles and represent a special kind of complex secondary lysosomes involved in the final degradation of endogenous (cell organelles) and exogenous material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229078
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Structure and function of the paraphysis cerebri in the rainbow trout, Salmo gairdneri Richardson (1985)
    Springer
    Cell & tissue research 242 (1985), S. 127-143 
    Details
    ISSN: 1432-0878
    Keywords: Paraphysis cerebri ; Histology ; Cytochemistry ; Electron microscopy ; Autoradiography ; Salmo gairdneri Richardson
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paraphysis cerebri of adult Salmo gairdneri is represented by a differentiated part of the pars impar telencephali of the telencephalic roof. It consists of a vaulted epithelial sheet, which displays only a few rostral evaginations and separates the cerebrospinal fluid (CSF) from the meningeal interstitial fluid. The fenestrated, sinusoidal portal system surrounding the paraphyseal epithelium appears to be part of a complex vascular bed of the dorsal telencephalic and diencephalic area. Myelinated and unmyelinated nerve fibers observed in the vicinity of the paraphyseal epithelium fail to make synaptic contact with paraphyseal cells. The single-layered epithelium is composed of characteristic, rather small, optically dense, cuboidal and cylindrical cells, apically mutually attached by junctional complexes including zonulae occludentes. These paraphyseal cells execute a high energetic and a moderate synthetic metabolism as indicated by ultrastructural, cytochemical and enzyme-cytochemical observations. Morphological evidence is presented for a multiple function of these cells in the regulation of the CSF: 1) water and solute elaboration into the ventricular system, 2) restricted uptake of high molecular weight organic substances from the CSF, 3) restricted uptake of low molecular weight substances from the CSF, but apparently not of GABA and of biogenic amines, 4) the formation and pinching-off of “blebs” as expression of a physiological mechanism not yet elucidated. The possible relationship between the level of development of the paraphysis cerebri and the sensitivity of animals to hydro-mineral metabolism is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225570
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Serotonin-immunoreactive neurones in the brain of Locusta migratoria innervating the corpus cardiacum (1988)
    Springer
    Cell & tissue research 254 (1988), S. 147-153 
    Details
    ISSN: 1432-0878
    Keywords: Corpus cardiacum ; Serotonin ; Immunocytochemistry ; Lucifer yellow ; Double labelling ; Locusta migratoria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The serotoninergic innervation of the corpus cardiacum (CC) of Locusta migratoria was investigated using two antisera against serotonin. A dense network of immunoreactive nerve fibres was present in the storage lobe of the CC. Immunopositive fibres only sporadically crossed the border between the storage lobe and the glandular lobe of the CC. Immunopositive fibres entered the storage lobe of the CC via the nervus corporis cardiaci I (NCCI); NCCII was immunonegative. Unilateral retrograde fillings of the NCCI with the fluorescent tracer Lucifer yellow, followed by antiserotonin immunocytochemistry, revealed about 20 double-labelled neurones in the anterior part of the pars intercerebralis. The double-labelled neurones were scattered between fluorescent non-immunoreactive neurones. Additionally, 5–7 neurones labelled only with Lucifer yellow were found at the ventrolateral side of the tritocerebrum. No immunopositive neurones were observed in the hypocerebral ganglion. Immunopositive fibres from neurones in the frontal ganglion ran via the recurrent nerve and the neuropile of the hypocerebral ganglion into the paired oesophageal nerve. At most, a few immunopositive nerve fibres occurred in the cardiostomatogastric nerves II, which connect the storage lobe of the CC with the paired oesophageal nerve at the caudal end of the hypocerebral ganglion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220028
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Co-localization of the adipokinetic hormones I and II in the same glandular cells and in the same secretory granules of corpus cardiacum of Locusta migratoria and Schistocerca gregaria (1987)
    Springer
    Cell & tissue research 249 (1987), S. 379-389 
    Details
    ISSN: 1432-0878
    Keywords: Adipokinetic hormones I and II ; Corpus cardiacum ; Immuno-electron microscopy ; Locusta migratoria ; Schistocerca gregaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The immunocytochemical reactivity of the glandular cells of the corpus cardiacum (CCG-cells) of Locusta migratoria and Schistocerca gregaria was investigated at the electron-microscopic level, using the protein A-gold method, with three antisera against fragments of the adipokinetic hormones AKH I and AKH II. This combination of antisera permitted discrimination between anti-AKH I and anti-AKH II immunoreactivity. Fixation in a mixture of 2% glutaraldehyde and 2% formaldehyde, in combination with low-temperature embedding in Lowicryl K4M, produced the highest and most consistent selective immunogold labelling of the secretory and ergastoplasmic granules. All secretory granules in all CCG-cells investigated possessed a distinct anti-AKH I-immunopositive reaction, whereas most secretory granules showed a weaker anti-AKH II immunoreaction. Ergastoplasmic granules reacted similar to the secretory granules. The average immunolabelling of the secretory granules was higher in the processes than in the cell bodies of the CCG-cells. The results in Schistocerca gregaria were essentially similar to those in Locusta migratoria. It is concluded that (i) the individual CCG-cells synthesize AKH I as well as AKH II; (ii) these hormones coexist in the same ergastoplasmic and secretory granules; and (iii) these granules contain a higher content of AKH I than AKH II.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215522
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...