bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anticipatory reward signals in ventral striatal neurons of behaving rats
Authors: Khamassi Mehdi , Mulder Antonius B. , Tabuchi Eiichi , Douchamps Vincent , Wiener Sidney I. 
Published: November 2008

AbstractIt has been proposed that the striatum plays a crucial role in learning to select appropriate actions, optimizing rewards according to the principles of ‘Actor–Critic’ models of trial‐and‐error learning. The ventral striatum (VS), as Critic, would employ a temporal difference (TD) learning algorithm to predict rewards and drive dopaminergic neurons. This study examined this model’s adequacy for VS responses to multiple rewards in rats. The respective arms of a plus‐maze provided rewards of varying magnitudes; multiple rewards were provided at 1‐s intervals while the rat stood still. Neurons discharged phasically prior to each reward, during both initial approach and immobile waiting, demonstrating that this signal is predictive and not simply motor‐related. In different neurons, responses could be greater for early, middle or late droplets in the sequence. Strikingly, this activity often reappeared after the final reward, as if in anticipation of yet another. In contrast, previous TD learning models show decremental reward‐prediction profiles during reward consumption due to a temporal‐order signal introduced to reproduce accurate timing in dopaminergic reward‐prediction error signals. To resolve this inconsistency in a biologically plausible manner, we adapted the TD learning model such that input information is nonhomogeneously distributed among different neurons. By suppressing reward temporal‐order signals and varying richness of spatial and visual input information, the model reproduced the experimental data. This validates the feasibility of a TD‐learning architecture where different groups of neurons participate in solving the task based on varied input information.
Mechanisms of substrate transport‐induced clustering of a glial glutamate transporter GLT‐1 in astroglial–neuronal cultures
Authors: Nakagawa Takayuki , Otsubo Yasuto , Yatani Yumi , Shirakawa Hisashi , Kaneko Shuji 
Published: November 2008

AbstractGlutamate uptake by the Na+‐dependent glutamate transporter GLT‐1, which is predominantly expressed in astrocytes, is crucial for regulating glutamate concentration at the synaptic cleft and achieving proper excitatory neurotransmission. A body of evidence suggests that GLT‐1 constitutively traffics between the plasma membrane and endosomes via an endocytosis/recycling pathway, and forms a cluster. Here, we report substrate transport via GLT‐1‐induced formation of GLT‐1 cluster accompanied by intracellular trafficking in rat astroglial–neuronal cultures. We constructed a recombinant adenovirus expressing enhanced green fluorescence protein (EGFP)‐tagged GLT‐1. Adenoviral infection resulted in the expression of functional GLT‐1–EGFP preferentially in astrocytes, partly as clusters. Treatment with glutamate, but notN‐methyl‐D‐aspartate, dramatically increased the number of GLT‐1 clusters within 1 h. The estimated EC50value of glutamate was 240 μm. In addition, glutamate decreased the cell surface expression and increased the intracellular expression of GLT‐1. The GLT‐1 clusters were found in early and recycling endosomes and partly in lysosomes, and were inhibited by blockade of endocytotic pathways. Ionotropic and metabotropic glutamate receptor antagonists had no effect on glutamate‐induced GLT‐1 clustering. The non‐transportable glutamate uptake inhibitors (2S,3S)‐3‐[3‐[4‐(trifluoromethyl)benzoylamino]benzyloxy]aspartate and dihydrokainate, as well as Na+‐free conditions, prevented the glutamate‐induced GLT‐1 clustering, whereas the competitive substrates, aspartate and L‐trans‐pyrrolidine‐2,4‐dicarboxylate, induced GLT‐1 clustering. Furthermore, the Na+/K+‐ATPase inhibitor, ouabain, and the Na+ionophores, gramicidin and monensin, produced GLT‐1 clustering. Modulators of intracellular Ca2+signaling or membrane depolarization had no effect on GLT‐1 clustering. Taken together, these results suggest that Na+influx associated with GLT‐1 substrate transport triggers the formation of GLT‐1 clusters accompanied by intracellular trafficking via endocytotic pathways in astrocytes.
Predominant expression of phospholipase Cβ1 in telencephalic principal neurons and cerebellar interneurons, and its close association with related signaling molecules in somatodendritic neuronal elements
Authors: Fukaya Masahiro , Uchigashima Motokazu , Nomura Sachi , Hasegawa Yuta , Kikuchi Hisaya , Watanabe Masahiko 
Published: November 2008

AbstractUpon activation of receptors coupled to the Gq subclass of G proteins, phospholipase C (PLC)β hydrolyses membrane phospholipid to yield a pair of second messengers, inositol 1,4,5‐trisphosphate and 1,2‐diacylglycerol. Of four PLCβ isoforms, PLCβ1 is transcribed predominantly in the telencephalon and its gene inactivation in mice impairs metabotropic glutamate receptor‐ and muscarinic acetylcholine receptor‐dependent hippocampal oscillations, endocannabinoid production in the hippocampus and barrel formation in the somatosensory cortex. Here we examined cellular and subcellular distributions of PLCβ1 in adult mouse brains. In the telencephalon, high levels of PLCβ1 were observed in principal neurons, including pyramidal cells in the cortex and hippocampus, granule cells and mossy cells in the dentate gyrus, and medium spiny neurons in the caudate‐putamen, whereas most interneurons had low levels of or were negative for PLCβ1 and, instead, expressed PLCβ4. By immunofluorescence, tiny clusters of PLCβ1 were distributed in somatodendritic compartments of principal neurons and positioned close to those of metabotropic glutamate receptor 5, muscarinic acetylcholine receptor M1 and diacylglycerol lipase‐α, respectively. Immunoelectron microscopy revealed that PLCβ1 was often associated with the smooth endoplasmic reticulum, cell membrane or postsynaptic density. In particular, it was highly accumulated at the perisynapse of dendritic spines forming asymmetrical synapses. In the cerebellum, PLCβ1 was generally low but was enriched in axons and dendrites of basket cells. These results suggest that PLCβ1 is the key effector in telencephalic principal neurons and cerebellar interneurons. Furthermore, the well‐orchestrated molecular arrangement appears to be the anatomical basis for the specificity, efficiency and convergence of the neuronal phosphoinositide signaling system.
INEQUALITY, INJUSTICE AND LEVELLING DOWN
Authors: Christiano Thomas , Braynen Will 
Published: November 2008

AbstractThe levelling down objection is the most serious objection to the principle of equality, but we think it can be conclusively defeated. It is serious because it pits the principle of equality squarely against the welfares of the persons whose welfares or resources are equalized. It suggests that there is something perverse about the principle of equality. In this paper, we argue that levelling down is not an implication of the principle of equality. To show this we offer a defence of, and partial elaboration of, what we call a common good conception of the principle of equality, which principle favours states in which everyone is better off to those in which everyone is worse off. We contrast this with what we call a purely structural conception of the principle of equality. The common good conception of equality involves two basic components: (1) in each circumstance there exists an ideal egalitarian distribution, which distributes equally all the available good in the distribution with the highest average welfare and (2) in evaluating how just the world is, it will matter how far the actual distribution is from the ideal distribution. The ideal egalitarian distribution in the circumstance is Pareto optimal and the approximation rule implies that Pareto superior states are less unjust than Pareto inferior states.1
Increased basal transepidermal water loss leads to elevation of some but not all stratum corneum serine proteases
Authors: Voegeli R. , Rawlings A. V. , Doppler S. , Schreier T. 
Published: November 2008

SynopsisThere are indications of elevation of some inflammatory serine proteases in barrier damaged skin (e.g. plasmin and urokinase). Moreover, many other serine protease activities are present such as desquamatory enzymes as well as a newly detected tryptase‐like serine protease. However, the activities of these proteases have never been correlated with stratum corneum (SC) barrier function. The activity of extractable key serine proteases (SC trypsin‐like kallikreins, SC chymotrypsin‐like kallikreins, SC tryptase‐like serine protease, urokinase and plasmin) was measured from the outermost layers of SC obtained from facial tape strippings in clinically normal subjects. The protein content of the tape strippings was quantified by absorption measurements with the novel infrared densitometer SquameScanTM 850A and the protease activities by the use of fluorogenic peptide substrates. SC barrier function, SC hydration and skin surface pH were measured using AquaFluxTM, NOVA dermal phase meter and Skin‐pH‐Meter®, respectively. As expected, SC hydration was reduced with increased transepidermal water loss (TEWL) values indicative of barrier impairment. Surprisingly, SC chymotrypsin‐like activity showed no correlation with hydration or TEWL, whereas all other enzymes positively correlated with impaired barrier function and some were statistically significant: SC trypsin‐like kallikreins (R2 = 0.66, P < 0.01), SC tryptase‐like enzyme (R2 = 0.95, P < 0.001), plasmin (R2 = 0.86, P < 0.001) and urokinase (R2 = 0.50, P < 0.05). All enzymes except urokinase also negatively correlated with SC hydration. Elevated levels of SC serine proteases have been associated with some dermatological disorders, such as atopic dermatitis, psoriasis and rosacea but these results indicate that these enzymes are also elevated with milder forms of barrier disruption, which is not clinically evident as irritated skin. As these proteases are elevated in the SC, they will also be elevated in the epidermis where they can be involved in neurogenic inflammation and epidermal barrier impairment via activation of the protease‐activated receptors. These results highlight the need for using serine protease inhibitors especially for urokinase and plasmin, SC tryptase‐like serine protease and possibly SC trypsin‐like kallikreins even in milder forms of barrier damage.
B‐cell diversity decreases in old age and is correlated with poor health status
Authors: Gibson Kate L. , Wu Yu‐Chang , Barnett Yvonne , Duggan Orla , Vaughan Robert , Kondeatis Elli , Nilsson Bengt‐Olof , Wikby Anders , Kipling David , Dunn‐Walters Deborah K. 
Published: November 2008

SummaryOlder people suffer from a decline in immune system, which affects their ability to respond to infections and to raise efficient responses to vaccines. Effective and specific antibodies in responses from older individuals are decreased in favour of non‐specific antibody production. We investigated the B‐cell repertoire in DNA samples from peripheral blood of individuals aged 86–94 years, and a control group aged 19–54 years, using spectratype analysis of the IGHV complementarity determining region (CDR)3. We found that a proportion of older individuals had a dramatic collapse in their B‐cell repertoire diversity. Sequencing of polymerase chain reaction products from a selection of samples indicated that this loss of diversity was characterized by clonal expansions of B cells in vivo. Statistical analysis of the spectratypes enabled objective comparisons and showed that loss of diversity correlated very strongly with the general health status of the individuals; a distorted spectratype can be used to predict frailty. Correlations with survival and vitamin B12 status were also seen. We conclude that B‐cell diversity can decrease dramatically with age and may have important implications for the immune health of older people. B‐cell immune frailty is also a marker of general frailty.
IMPERFECT COMPETITION AND THE COBWEB THEOREM: A VEGETABLE CASE
Authors: RIDLER DUNCAN 
Published: November 2008

SummaryProducer price changes are dependent on final demand, marketed volume and marketing cost, but the less than perfect competition which may determine this last is ignored in formulating the cobweb theorem. Attention to monopsonistic buying of farm products has importance in the choice between stabilisation measures directed at producers and marketing firms, and also as regards the need for integration of the theory of imperfect competition and the analysis of agricultural price cycles.Cyclical instability is a serious problem in the New Zealand vegetable industry. The size and inflexibility of retail margins significantly accentuate producer price fluctuations. Auctions are the main mechanism for price formation, and high retail margins appear to be permitted by the non‐competitive elements in this marketing system. The most promising avenues for improvement would be in reform of auction procedures and exploration of alternative marketing channels for vegetables.
THE IMPACT OF PUBLIC WORKS SCHEMES ON FARMING: A CASE STUDY RELATING TO A RESERVOIR AND POWER STATION IN NORTH WALES
Authors: Jones W. Dyfri 
Published: November 2008

This is a study of the economic effects on farming of building a reservoir and an atomic power station in two rural areas in North Wales. Whilst these schemes undoubtedly caused much unpleasantness and serious difficulties which should not be understated and overlooked, their economic effects were not as drastic and detrimental as was at first feared by the farming community and others concerned with their well‐being. In retrospect their predominant effect was the speeding up of a process of readjustment which was already taking place, for which most of the remaining farmers may well be grateful and which those more seriously affected probably now regard as an unpleasant experience which was inevitable but which came rather suddenly.There are many lessons to be learnt from the history of these schemes. In particular, the methods of assessing both the value of land acquired compulsorily for development and the amount of compensation payable for disturbance need reviewing, in order that they may be related more closely to economic and social realities.
A FRAMEWORK FOR ANALYSING THE CONTRIBUTION OF THE AGRICULTURAL SECTOR TO ECONOMIC DEVELOPMENT
Authors: Ritson Christopher 
Published: November 2008

This paper describes a framework for analysing the contribution of the agricultural sector to economic development, and gives a brief example of how such analysis might be used to aid the understanding of contemporary policy problems. The framework is in the style of labour surplus development models, the best known of which are by Lewis* and Ranis and Fei.†RésuméCADRE DE TRAVAIL EN VUE D'ANALYSER L'APPORT DU SECTEUR AGRICOLE AU DÉVELOPPEMENT ÉCONOMIQUECe texte nous donne la description d'un cadre directeur de travail en vue d'analyser l'apport du secteur agricole au développement économique, en y ajoutant un exemple succinct de la manière dont pourrait étre utilisée cette analyse pour aider à la compréhension des problèmes contemporains de la prise des décisions primordiales. Ce cadre de travail appartient au style des exemples pilotes du développement fondé sur le surplus de main‐d'oeuvre, dont les plus connus sont ceux de Lewis et de Ranis et Fei.ZusammenfassungL'exemple cité ici est celui de la détermination des salaires à la Jamaîque.Diese Arbeit entwirft einen Rahmen für die Analyse des Beitrags des Landwirtschaftssektors zur Wirtschaftsentwicklung und gibt kurz ein Beispiel wie eine derartige Analyse für eirt besseres Verständnis gegenwärtiger Verfahrensprobleme benutzt werden kann. Der Rahmen gleicht Entwicklungsmodellen für Überbeschäftigung, von denen die bekanntesten von Lewis und Ranis und Fei stammen.Beispiel ist die Lohnfestsetzung in Jamaika.
LOOKING AT THE FUTURE OF AGRICULTURE PRESIDENTIAL ADDRESS
Authors: Thomas Professor W. J. 
Published: November 2008

This paper takes a brief look at world prospects for the demand for and the supply of food. It is based mainly on the documentation of the Food and Agricultural Organisation of the United Nations. The contrast between the position in developed and developing countries is highlighted and some of the ensuing problems of feeding the world population are examined. Finally, certain lessons regarding the development of agricultural economics within this context are drawn.RésuméCOUP D'OEIL SUR L'AVENIR DE L'AGRICULTUREL'auteur de cet article jette un rapide regard sur les perspectives mondiales de la demande et de l'offre des produits alimentaires. Ses données reposent principalement sur la documentation de l'Organisation des Nations unies pour l'Alimentation et l'Agriculture. Il met en évidence le contraste entre la situation des pays développés et celle des pays en voie de développement et examine certains des problèmes que pose l'alimentation de la population mondiale, pour finalement tirer plusieurs leçons concernant le développement de l'économie agricole dans ce contexte.ZusammenfassungEIN BLICK IN DIE ZUKUNFT DER LANDWIRTSCHAFTDieser Artikel wirft einen kurzen Blick auf die Aussichten der Welt auf die Nachfrage und das Angebot von Nahrung. Er stützt sich hauptsächlich auf die Dokumentation der Nahrungs‐und landwirtschaftlichen Organisation der Vereinten Nationen. Der Kontrast zwischen der Stellung der entwickelten und der Entwicklungsländer wird aufgezeigt, und es werden einige dersich ergebenden Probleme, die Weltbevölkerung zu ernähren, untersucht. Schliesslich werden einige Schlussfolgerungen für die Entwicklung der landwirtschaftlichen Wirtschaft in diesem Zusammenhang gemacht.
LABOUR AND UPLAND RICE PRODUCTION
Authors: Njoku Athanasius O. , Karr Gerald L. 
Published: November 2008

This paper, with the use of field data collected from 106 farm households in Sierra Leone, evaluates the ‘labour‐surplus model’ for West African rice farms. The analysis of labour utilisation on traditional upland farms suggest the existence of economies of size for selected work activities. Labour organisation and the quality of labour used on larger farms help to explain the benefits of size. It is noted that over the long‐run the expansion of upland rice cultivation in Sierra Leone will confront a land availability constraint.RésuméMAIN‐D'OEUVRE ET PRODUCTION RIZIÈRE SUR TERRES ÉLEVÉESLes auteurs, se servant de données recueillies sur le terrain en provenance de 106 exploitations individuelles situées au Sierra Leone, font une évaluation du ‘modèle de surplus de main‐d'oeuvre’ pour les rizeries de l'Afrique occidentale. L'analyse de l'utilisation de la main‐d'oeuvre dans les exploitations traditionnelles des hautes terres permet de conclure à la possibilité d'économies d'échelle pour certains travaux sélectionnés. L'organisation du travail et la qualité de la main‐d'oeuvre employée dans les exploitations de grande taille contribuent à l'explication des bénéfices de dimension. L'étude constate qu'à la longue, l'extension des cultures rizières sur terrains élevés au Sierra Leone finira par se heurter à une contrainte en matière de disponibilités de terres.ZusammenfassungARBEIT UND OBERLANDREISPRODUKTIONDieser Artikel evaluiert unter Verwendung von Forschungsunterlagen, die von 106 Farmhaushalten in Sierra Leone gesammelt wurden, das ‘Arbeits überschussmodell’ für westafrikanische Reisfarmer. Die Analyse der Arbeitsnutzung auf traditionellen Oberlandfarmen führt zu dem Schluss, dass Grössenwirtschaften für ausgesuchte Tätigkeitsaktivitäten bestehen sollten. Arbeits‐organisation und Arbeitsqualität, die auf grösseren Farmen genutzt werden, helfen, die Vorteile der Grösse zu erklären. Es wird festgestellt, dass die Ausdehnung des Oberlandreisanbaus in Sierre Leone langfristig auf Landbeschränkungen stossen wird.
FARM‐FIRM NORMATIVE FERTILISER DEMAND RESPONSE IN THE NORTH CENTRAL STATE OF NIGERIA
Authors: Ogunfowora O. , Norman D. W. 
Published: November 2008

Fertiliser application is one of the most important factors of increased agricultural production in the developing countries. However, the demand for fertiliser depends, amongst other factors, on the profitability of using it and the availability of funds to purchase fertiliser. This paper uses a combination of parametric programming and multiple regression models to estimate the farm‐firm elasticities of demand for fertiliser in an environment where no time‐series data exist and where the system of intercropping is the norm. The results lend support to the popular belief that capital supply has the highest potential for inducing a demand for fertiliser, followed by fertiliser and output price changes.RésuméRÉACTION NORMATIVE DE LA DEMANDE D'ENGRAIS DANS LES ENTREPRISES DE CULTURE COMMERCIALE DE L'ETAT DU CENTRE‐NORD NIGÉRIAL'application des engrais est un des facteurs les plus importants de l'accroissement de la production agricole dans les pays en développement. Toutefois, la demande pour les engrais dépend, entre autres, de la rentabilité de leur utilisation et de la mise à disposition de capitaux pour pouvoir les acheter. La présente étude repose sur l'emptoi conjugué de modèles de programmation paramètrique et de régression multiple pour estimer les élasticités de la demande d'engrais de la part des exploitations agricoles à but commercial, dans un milieu où l'on ne dispose pas de données obtenues par séries chronologiques et où le système des cultures dérobées est la norme. Les résultats apportent des arguments en faveur de la thèse populaire selon laquelle, parmi les facteurs d'incitation à la demande d'engrais, c'est la fourniture de capitaux qui a le plus de poids, suivie par l'évolution des prix des engrais et des prix à la production.ZusammenfassungEINE ANTWORT AUF DIE FARMBESTIMMTE NORMATIVE DÜNGERNACHFRAGE IM NÖRDLICHEN ZENTRALSTAAT NIGERIASDer Gebrauch von Dünger ist einer der wichtigsten Faktoren der wachsenden landwirtschaftlichen Produktion in Entwicklungsländern. Die Nachfrage nach Dünger hängt jedoch unter anderem davon ab, wie nützlich der Gebrauch ist und wie Geldquellen zur Verfügung stehen, um Dünger zu kaufen. Dieser Artikel benützt eine Kombination von parametrischer Programmierung und multiplen Regressionsmodellen, um die farmbestimmten Nach‐frageelastizitäten für Dünger in einer Umgebung zu schätzen, für die keine Zeitreihenunterlagen existieren und in der das System der Zwischenernte der Regelfall ist. Die Ergebnisse bestärken die allgemeine Ansicht, dass das Gewähren von Kapital die grösste Möglichkeit hat, Nachfrage nach Dünger zu induzieren, worauf Dünger‐ und Outputpreisveränderungen folgen.