bluuebunny/crossref_metadata_2025 huggingface dataset:
Issues in Canadian Agricultural Economic Data: A Selected Review
Authors: Lerohl M. L.
Published: November 2008

This article expresses the concern that major agricultural data series fail to reflect well changes in efficiency or incomes of those engaged in the industry. Current farm income data focus on income from farm sources, and a shift in emphasis is suggested to value‐added by farming and nonfarm agriculture businesses, to total incomes rather than farm incomes of those engaged in farming, and to asset accounts for those producing farm products. The result would be better understanding of the contribution of agriculture to the economy, and better understanding of the well‐being of farm people. This may also be an appropriate time to question the value of the farm as a unit for collecting or for publishing agricultural data, as well as a time to seriously rethink the data implications of long‐run resource issues in agriculture.

Ľauteur s'inquiète de ce que les principales séries de données agricoles ne reflètent pas adéquatement les changements survenus au chapitre de ľefficacité ni au chapitre des revenus chez les personnes engagées dans ce secteur. Les données actuelles sur les revenus de ľexploitation agricole mettent ľaccent sur les sources de revenu propres a ľagriculture et ľauteur soutient que Ton devrait s'intéresser davantage à la valeur ajoutée par ľagriculture et par les activités agricoles extérieures à ľexploitation agricole, insister sur les revenus totaux plutôt que sur les revenus agricoles des personnes engagées dans le secteur et mettre ľaccent sur les comptes de valeurs des producteurs agricoles. On parviendrait ainsi à mieux comprendre la contribution de ľagriculture à ľéconomic et le problème du bien‐être des agriculteurs. Le temps est peut‐être également venu de remettre en question la valeur de ľexploitation agricole comme unité de collecte ou de publication de données agricoles ainsi que de repenser sérieusement les incidences que pourront avoir sur les données les questions relatives aux ressources à long terme en agriculture.
The Demand and Supply of Norwegian Atlantic Salmon in the United States and the European Community
Authors: Herrmann Mark , Lin Biing‐Hwan
Published: November 2008

A simultaneous‐equation model of the demand and supply of Norwegian Atlantic salmon in the United States and the European Community is constructed, and sensitivity analyses are conducted to measure the effects of changing exchange rates, the Norwegian supply of Atlantic salmon, and prices of North American Pacific salmon. Using monthly statistics from January 1983 through March 1987, the demand for Norwegian Atlantic salmon is found to be highly seasonal, and highly price and income elastic in the United States and the European Community. Chinook is found to be a weak substitute for Norwegian Atlantic salmon in the U.S., and frozen chinook, sockeye and coho in the European Community are also found to be weak substitutes for Norwegian Atlantic salmon.

Nous avons élaboré un modéle à équations simultanées de la demande et de ľapprovisionnement pour le saumon de ľAtlantique provenant de Norvège, aux États‐Unis et dans la Communauté européenne, et nous avons precédé à des analyses de sensibilité afin de mesurer les effets de la variation des taux de change, des approvisionnements de saumon de ľAtlantique de Norvège et des prix du saumon du Pacifique provenant ďAmérique du Nord. En nous fondant sur les statistiques mensuelles recueillies de Janvier 1983 à mars 1987, nous avons constaté que la demande de saumon de ľAtlantique provenant de Norvège est extrêmement saisonnière et qu'elle est élastique par rapport aux prix et aux revenus, aux États‐Unis et dans la Communauté européenne. Le saumon quinnat (chinook) s'est avéré un piètre produit de remplacement du saumon de ľAtlantique provenant de Norvège dans la Communauté européenne.
Cost Structure and Performance of Prairie Grain and Oilseed Farms
Authors: Culver David , Strain Greg , Ehrensaft Philip
Published: November 2008

The views expressed in this paper are those of the authors and do not necessarily represent the views of Agriculture Canada
A Simple Duality Model of Production Incorporatin Risk Aversion and Price Uncertainty
Authors: Coyle Barry T.
Published: November 2008

Proceeding within the framework of a linear mean‐variance utility function, this paper outlines a duality model of production that incorporates risk aversion and price uncertainty. In contrast to risk models based on an expected utility function, this model provides a practical alternative to standard duality models for econometric research.
Obtaining Management Profiles of Ontario Swine Producers Through Cluster Analysis
Authors: Rosenberg Alejandro , Turvey Calum G.
Published: November 2008

This paper develops managerial profiles of Ontario Swine Producers for extension use, using mail survey data and cluster analysis. Results indicate that there are four major discriminant variables which can be used to identify different classes of farmers. These management profiles can be used for targeted extension efforts.
The Impact of the Proposed June 1987 Income Tax System on Saskatchewan Grain and Hog Operations
Authors: Schoney R. A. , Brown W. J. , Rinholm R. A.
Published: November 2008

The changes to the federal income tax system proposed in June 1987 are analyzed for their impact on farm size and competitiveness of Saskatchewan grain and hog operations. Farm growth, income and income taxes paid are simulated over a 20‐year period. The June 1987 proposed tax system is projected to be progressive in taxing grain operations when there is no land inflation and excess depreciation is recaptured, but is nearly neutral or slightly regressive when the Saskatchewan livestock tax credits are taken into account. Assuming no land inflation and recapture of excess depreciation, small grain operations pay less income tax than small livestock operations, medium‐sized grain operations pay slightly more but large grain operations pay considerably more taxes than the corresponding hog operations. The elimination of the capital cost allowance recapture tends to increase the competitive advantage of the hog operation over the grain operation, but a modest 4% annual increase in land values coupled with capital gains exemptions increase dramatically the overall competitive advantage of the grain operation over the hog operation.

Les modifications apportées au régime d'impôt sur le revenu proposé en juin 1987 sont analysées pour leurs répercussions sur la taille des exploitations et la compétitivité des céréaliculteurs et des éleveurs de pores de la Saskatchewan. On a simulé la croissance des exploitations, le revenu et les impôts sur le revenu payés au cours d'une période de 20 ans. Le régime fiscal proposé de juin 1987 se veut progressif dans l'imposition des fermes céréalières lorsqu'il n'y a pas d'inflation du prix des terres et que l'amortissement excédentaire est récupéré, mais est pratiquement sans incidence sur les fermes ou légerement régressif à cause des crédits d'impôt consentis sur le bétail de la province. En sup‐posant l'absence d'inflation du prix des terres et la récupération de l'amortissement excédentaire, les petits producteurs de céréales paient moins d'impôt sur le revenu que les petits éleveurs de bétail, les producteurs moyens en patient légèrement plus, mais les gros producteurs paient beaucoup plus d'impôt que les éleveurs correspondants de pores. L'élimina‐tion de la déduction pour amortissement a tendance à accroître l'avantage concurrentiel des éleveurs par rapport aux producteurs, mais un modeste 4% d'augmentation annuelle de la valeur des terres, conjugué à des exonérations pour gains en capital, augmente de facon dramatique l'avantage concurrentiel global dont jouit le producteur par rapport à l'éleveur de pores.
Trade Policy Implications of Sustainable Agriculture
Authors: Vasavada Utpal
Published: November 2008

“Les gouvernements peuvent utiliser de nombreux leviers économiques pour assurer un développement respecteux de l'environnement, et exercer leur influence par des impôts, de l'aide financeère, des politiques et des règlements, des accords, de la recherche‐développement, des crédits à l'exportation, des subventions au développement régional, des baux d'exploitation des ressources, des politiques de commercialisation, des tarifs douaniers et des déductions pour amortissement”.
The Effects of Alternative Methods of Crow Benefit Payment on Economic Rents of Farm Input Suppliers in Western Canada
Authors: Sarwar Ghulam , Fox Glenn
Published: November 2008

This paper uses a multi‐market partial equilibrium model to assess the impact of selected alternative methods of payment of the Crow Benefit on the economic welfare of farm input suppliers for the feed grain sector in western Canada. the model is calibrated using data representative of the period from 1986 to 1988. Inputs are grouped into categories of land, labor, machinery and buildings, and other purchased inputs. Impacts of alternative policy regimes are found to differ substantially by the characteristics of the particular policy proposal and also by the nature of the input in question. Input suppliers would be worse off under the method of payment embodied in the so‐called Gilson, 50:50 and Agricultural Diversification Alliance proposals, but would be better off under the Grain Trasportation Refund plan. Adverse impacts on landowne welfare, measured as percentage change in economic rents received, would be larger than the effects on other input suppliers, in some cases exceeding 10% of the rents received under the status quo.

L'étude utilise un modèle multi‐marchéàéquilibre partiel pour évaluer les incidences de diverses méthodes de paiement du montant compensatoire du Nid‐de‐Corbeau sur la situation économique des agrofournisseurs du secteur des céréles de provendes dans l'ouest du Canads. Le modèle est étalonné au moyen de données représentatives d'une période allant de 1986 à 1988. Les intrants sont groupés en catégories: fonds de terre, main‐d'oeuvre, machinerie et bâtiments et autres fournitures achetées. Les effets des divers régimes diffèrent sensiblement par les caractères du projet do politique et aussi par la nature des intrants en question. La situation des fournisseurs serait empirée si l'on emploie la méthode de paicment comprise dans les programmes Gilson, 50:50 et Agricultural Diversification Alliance, mais elle serait meilleure avec le plan de remboursement sur le transport du grain. Les effets négatifs sur la situation des propriétaires de terre, mesurés par le changement en pourcentage du loiyer économique reçu, étaient plus importants que les effets sur les autres catégories d'agrofournisseurs, dépassant parfois 10% du loye reçu dans le régime actuel.
Welfare Calculations in a Distributed Lag Model: Beans in Colombia
Authors: Janssen Willem
Published: November 2008

Distributed lag functions are very popular for modeling supply behavior, but there is little published on their use for estimating welfare effects. A partial equilibrium model for beans in Colombia is used to derive the welfare parameters for distributed lag supply functions. Welfare calculations are made for a zero trade and a free trade scenario. The results of welfare calculations with the distributed lag supply functions are compared with the results of simple (undistributed) one‐lag supply functions. Sensitivity analysis on price and lag coefficients is applied. Whereas the simple supply functions would lead to the conclusion that the free trade scenario would have brought most benefits, the distributed lag specification leads to the conclusion that for certain conditions the zero trade scenario would have been more beneficial. The reasons for the diverging results are explored.

Les fonctions à retard échelonné sont très utilisées pour la modélisation du comportement d'approvisionnement, mais leur utilié pour estimer les effets sur la qualité de la vie est peu documenée. Un modéle d'équilibre partiel pour la production des haricots en Colombie est utilisé dans le but de dégager les paramètres sociaux pour des fonctions d'approvisionnement à retard échelonné. Les caculs des effets sociaux sont basés sur un scénario de commerce extérieur nu1 et sur un scénario de libre‐échange. Les résultats des calculs sociaux obtenus avec la fonction d'approvisionnement à retard échelonné sont comparés avec ceux des fonctions d'approvisionnement á retard èhelonnè sont comparè avec ceux des fonctions d'approvisionnement simple (non échelonné) a un regard. Une analyse de sensibilité est faite sur les coefficient de prix et sur les coefficients de retard. Alors que les fonctions d'approvisionnement simple sembleraient indiquer que c'est le scénario de libreéchange qui aurait été le plus profitable, l'introduction de la fonction à retard échelonné améne à la conclusion que dans certaines conditions le scénario de commerce extérieur nul aurait été plus avantageux. Les raisons de cette divergence sont examinées.
Nonf arm Labor Market Participation of Farm Women
Authors: Olfert M. Rose , Taylor Julia S. , Stabler Jack C.
Published: November 2008

Structural changes in Saskatchewan agriculture have led to significant changes in the time allocation of labor of farm women. This paper analyzes the nonfarm labor market participation and labor supply of farm women in the theoretical context of a household production function and contrasts them with those of men. Participation is analyzed using probit models, and nonfarm labor supply functions are estimated using tobit models. Personal characteristics such as age, education, number of children and nonfarm labor participation of the spouse are significantly related to the nonfarm labor market participation and labor supply of farm women, and the direction of influence is as expected. Farm characteristics such as farm size and type are significant in the case of males but not for females. Labor market characteristics are represented only by distance to the nearest center of Complete Shopping Center status or higher and, while this variable is negatively significant for males as expected, it is not significant for females

Les changements structurels qui on frappé l'agriculture de la Saskatchewan ont entraîné des modifications significatives à la répartition du temps des agricultrices en matière de travail. L'article présente une analyse de la participation au marché du travail non agricole, ainsi que de l'offre de main‐d'oeuvre des agricultrices, dans le contexte théorique d'une fonction de production de ménage, en comparaison avec la situation observée chez les hommes. Le degré de participation e'tait analysé à partir de modèles probit et les fonctions d'offre de main‐d'oeuvre non agricole étaient estimées à partir de modéles tobit. Les caractères personnels comme l'âge, I'instruction, le nombre d'enfants et la participation du conjoint à un travail non agricole étaient significativement reliés, dans le sens attendu, à la participation des femmes au marché du travail non agricole et au temps qu'elles pouvaient y consacrer. Les caractères de l'exploitation, superficie et type, n'étaient significatifs que pour les hommes mais pas pour les femmes. Le seul caractére du marché de main‐d'oeuvre considéré était la distance entre la ferme et l'agglomération la plus proche de niveau de centre commercial complet ou de niveau supérieur. Bien que, comme on pouvait s'y attendre, cette variable était significativement négative dans le cas des hommes, elle n'avait pas de valeur significative pour les femmes
Optimal Producer Investment in Generic Advertising: The Case of Fluid Milk in Ontario and Quebec
Authors: Goddard E. W. , McCutcheon M. L.
Published: November 2008

The fluid milk sectors in Ontario and Quebec operate under myriad restrictions reflecting the supply management system in place. Active advertising campaigns for fluid milk are undertaken by producer organizations in each province. In Ontario, the provincial government contributes to the provincial advertising campaign.

To investigate the implications of the advertising programs, econometric models of the Ontario and Quebec milk sectors are specified, estimated and simulated. Given the measured responses to advertising, optimal advertising expenditure rules are applied to the Ontario and Quebec milk sectors to evaluate the implications of moving from actual to optimal advertising expenditure for producer welfare.

Les secteurs du lait de consommation de l'Ontario et du Québec fonctionnent sous une myriade de restrictions attachees au système actuel de gestion de l'offre. Des campagnes de publicité vigoureuses pour la consommation du lait sont entreprises dans chaque province par les organisations de producteurs et en Ontario le gouvernement provincial donne son appui financier à la campagne de publicité provinciate. Pour scruter les implications des programmes de promotion, les auteurs ont construit, évalué et appliqué en simulation des modèles économiques du secteur du lait de consommation des deux provinces. À la lumière des réactions mesurées à l'égard de la publicité, des règies de dépenses de publicité optimales sont appliquées aux deux secteurs, afin d'évaluer ce que le passage du niveau de promotion actuel à un niveau optimal signifierait pour la situation économique des producteurs.
Challenges Facing Environmentally Sustainable Ground Water Use in South Africa
Authors: Seward Paul
Published: November 2008

In 1998, South Africa promulgated a Water Act that is widely regarded as one of the most progressive and enabling pieces of environmental legislation in the world. The environmental aspects of the Water Act are commonly referred to as “resource‐directed measures.” These measures attempt to find the right balance between (1) leaving water in the resource (“nonconsumptive use”) to provide ecological goods and services for society and (2) taking the water out of the system for “consumptive” human use. These measures also attempt to ensure that both nonconsumptive and consumptive use is sustainable. This article discusses some of the challenges faced in using the measures to achieve environmentally sustainable ground water use. A major challenge is that misunderstanding still abounds regarding the environmental aims of this legislation. Other major challenges identified included a severe shortage of technical capacity, an inordinately long water use license application process, incorporating adaptive management to deal with uncertainty, incorporating the public participation process, and revising policy implementation processes to accommodate highly localized aquifers. Selecting appropriate scientific methodology—neither too simplistic nor too involved—is a recurring challenge. It is suggested that an important part of addressing these and the other challenges identified is a period of reflection and dialogue between the various sectors involved.
MICRO AND SMALL ENTERPRISE GROWTH IN TURKEY: UNDER THE SHADOW OF FINANCIAL CRISIS
Authors: ÖZAR ŠEmsa , ÖZERTAN Gökhan , İRFANOĞLU Zeynep Burcu
Published: November 2008

The present study analyzes the impacts of selected factors on the growth of micro and small enterprises (MSE) in Turkey. Using unique national field survey data on urban MSE that engage 1–49 persons, we present the determinants of MSE growth for the period between the start‐up of enterprises and the year 2000. We evaluate the impact of the financial crisis experienced in Turkey in 2001 on MSE. Detrimental effects of the crisis on MSE are clearly detected in our estimations. Some of the factors contributing to the growth of MSE lose their influence almost immediately during the crisis; indeed, the impact of some factors is reversed. Overall results reveal that there is much scope to design supportive policies for MSE to enable them to withstand the negative impacts of future crises, especially in emerging economies.
Innovative approach to health promotion for the over 45s: using a health check log
Authors: Sheriff June N. , Chenoweth Lynn
Published: November 2008

Objectives. To determine effectiveness of the health check log (HCL) in promoting health‐related quality of life and health awareness, health monitoring skills and timely consultation with health professionals for a cohort of community‐dwelling people over 45 years, compared with a similar cohort not recording the HCL.

Design. An exploratory longitudinal study using a quasi‐experimental methodology and data triangulation. Outcome measures included the SF‐36 health survey; a semi‐structured participant feedback survey and participant focus group discussions.

Sample. A convenience sample (n = 309) of community dwellers over the age of 45 living in the South Eastern Sydney/Illawarra Area Health Service, Sydney, Australia.

Results. The majority of participants recording the HCL reported health benefits. The SF‐36 health survey found younger age is a predictor for positive change in ‘social functioning’ (β = −0.14,t = 2.25,P < 0.05), while non‐pension income was a predictor of positive ‘physical functioning’ (β = 0.12,t = 2.02,P < 0.05) and ‘general health’ (β = 0.13,t = 2.11,P < 0.05). Alternatively, full‐time employment (β = −0.12,t = 2.02,P < 0.05) and not living alone (β = 0.18,t = 3.09,P < 0.01) predicted negative change in ‘role – physical’. Participant reactions to recording the HCL via feedback survey and focus group discussions were mostly positive.

Conclusions. The majority who maintained the HCL benefited by achieving improved health and knowledge of health monitoring, which was, however, moderated by age, income source, employment status and living arrangements.
Characterization of polymorphic microsatellite markers in the Dalmatian wall lizard Podarcis melisellensis (Squamata: Lacertidae)
Authors: HUYGHE K. , BREUGELMANS K. , SMALL M. , TADIĆ Z. , VAN DAMME R. , VANHOOYDONCK B. , BACKELJAU T.
Published: November 2008

We describe polymerase chain reaction primers and amplification conditions for 13 highly polymorphic microsatellite DNA loci isolated from the Dalmatian wall lizard, Podarcis melisellensis. The number of alleles per locus ranged from 12 to 41, with levels of observed heterozygosity between 0.62 and 0.94. Most of these loci were successfully cross‐amplified in the closely related species P. sicula, but levels of polymorphism were always lower.
IBDSim: a computer program to simulate genotypic data under isolation by distance
Authors: LEBLOIS RAPHAËL , ESTOUP ARNAUD , ROUSSET FRANÇOIS
Published: November 2008

IBDSim is a package for the simulation of genotypic data under isolation by distance. It is based on a backward ‘generation by generation’ coalescent algorithm allowing the consideration of various isolation by distance models with discrete subpopulations as well as continuous populations. Many dispersal distributions can be considered as well as heterogeneities in space and time of the demographic parameters. Typical applications of our program include (i) the study of the effect of various sampling, mutational and demographic factors on the pattern of genetic variation; and (ii) the production of test data sets to assess the influence of these factors on inferential methods available to analyse genotypic data.
Nonequivalence of Inhaled and Nebulized Salbutamol in the Assessment of Endothelial Dysfunction
Authors: Soiza Roy L. , Bhat M. Yaqoob , Crilly Mike A. , Williams David J. P.
Published: November 2008

A noninvasive measure of global endothelial dysfunction may be obtained by pulse wave analysis (PWA) before and after administration of inhaled salbutamol. As some subjects may have difficulty using an inhaler, we determined whether equivalent doses of inhaled and nebulized salbutamol produced similar effects on a key measure obtained from PWA—the augmentation index (AIx). Twenty volunteers (11 with vascular risk factors and 9 healthy controls) underwent PWA at the right radial artery using SphygmoCor. Subjects were randomized to receive either 400 μg inhaled salbutamol via spacer device or 2.5 mg nebulized salbutamol. PWA was performed until there was no further drop in AIx. After AIx returned to baseline, salbutamol was administered via the alternative route and measurements were repeated. The primary outcome was the intraclass correlation coefficient of agreement (ICC) between maximum change in AIx following inhaled and nebulized salbutamol. The ICC was 0.32 (95% CI −0.07 to 0.64) and 0.39 (95% CI −0.04 to 0.70) with and without correction for heart rate. The median maximum decrease in AIx after inhaler was 4.8% (IQR 1.8–7.1), and after nebulizer was 8.5% (IQR 7.5–11.4) (p= <.001). When corrected for heart rate, the median maximum fall in AIx after inhaler was 4.0% (IQR 2.0–7.9) and after nebulized salbutamol was 5.0% (IQR 3.8–9.6) (p= 0.24). Although inhaled and nebulized salbutamol produced similar median reductions in AIx, the correlation between the two methods of salbutamol delivery was weak. Further research is required to validate the fall in AIx after nebulized salbutamol as a measure of endothelial dysfunction.
TC‐5214 (S‐(+)‐Mecamylamine): A Neuronal Nicotinic Receptor Modulator with Antidepressant Activity
Authors: Lippiello Patrick M. , Beaver Jessica S. , Gatto Gregory J. , James John W. , Jordan Kristen G. , Traina Vincent M. , Xie Jianxun , Bencherif Merouane
Published: November 2008

Both clinical and preclinical data support a potential therapeutic benefit of modulating the activity of CNS neuronal nicotinic receptors (NNRs) to treat depression and anxiety disorders. Based on the notion that the depressive states involve hypercholinergic tone, we have examined the potential palliative role of NNR antagonism in these disorders, using TC‐5214 (S‐(+) enantiomer of mecamylamine), a noncompetitive NNR antagonist. TC‐5214 demonstrated positive effects in a number of animal models of depression and anxiety. TC‐5214 was active in the forced swim test in rats (minimum effective dose (MED) = 3 mg/kg i.p.), a classical depression model. It was also active in the behavioral despair test in mice (0.1–3.0 mg/kg i.p.), another model of depression. In the social interaction paradigm in rats, a model of generalized anxiety disorder (GAD), TC‐5214 was active at a dose of 0.05 mg/kg s.c. In the light/dark chamber paradigm in rats, a model of GAD and phobia, TC‐5214 was also active at a dose of 0.05 mg/kg s.c. Although TC‐5214 shows modest selectivity among NNR subtypes, the antidepressant and anxiolytic effects seen in these studies are likely attributable to antagonist effects at the α4β2 NNRs. This is supported by the observation of similar effects with α4β2‐selective partial agonists such as cytisine and with α4β2‐selective antagonists such as TC‐2216. TC‐5214 was well tolerated in acute and chronic toxicity studies in mice, rats, and dogs, showed no mutagenicity and displayed safety pharmacology, pharmacokinetic and metabolic profiles appropriate for therapeutic development. Overall, the results support a novel nicotinic cholinergic antagonist mechanism for antidepressant and anxiolytic effects and highlight the potential of NNR antagonists such as TC‐5214 as therapeutics for the treatment of anxiety and depression.
Enhancing Aromatic L‐amino Acid Decarboxylase Activity: Implications for L‐DOPA Treatment in Parkinson's Disease
Authors: Hadjiconstantinou Maria , Neff Norton H.
Published: November 2008

Aromatic L‐amino acid decarboxylase (AAAD) is an essential enzyme for the formation of catecholamines, indolamines, and trace amines. Moreover, it is a required enzyme for converting L‐DOPA to dopamine when treating patients with Parkinson's disease (PD). There is now substantial evidence that the activity of AAAD in striatum is regulated by activation and induction, and second messengers play a role. Enzyme activity can be modulated by drugs acting on a number of neurotransmitter receptors including dopamine (D1–4), glutamate (NMDA), serotonin (5‐HT1A, 5‐HT2A) and nicotinic acetylcholine receptors. Generally, antagonists enhance AAAD activity; while, agonists may diminish it. Enhancement of AAAD activity is functional, as the formation of dopamine from exogenous L‐DOPA mirrors activity. Following a lesion of nigrostriatal dopaminergic neurons, AAAD in striatum responds more robustly to pharmacological manipulations, and this is true for the decarboxylation of exogenous L‐DOPA as well. We review the evidence for parallel modulation of AAAD activity and L‐DOPA decarboxylation and propose that this knowledge can be exploited to optimize the formation of dopamine from exogenous L‐DOPA. This information can be used as a blue print for the design of novel L‐DOPA treatment adjuvants to benefit patients with PD.
Glucocorticoid‐induced osteoporosis
Authors: SAMBROOK Philip N
Published: November 2008

Introduction:  Glucocorticoids have major effects on bone metabolism, leading to accelerated osteoporosis and fracture.

Methods:  This review will attempt to summarize current knowledge about their effects in light of new information and important remaining questions, especially with respect to management of this common clinical problem.

Results:  Glucocorticoids affect bone through multiple pathways, influencing both bone formation and bone resorption. Evidence from randomised trials suggests that postmenopausal women receiving glucocorticoids are at greatest risk of rapid bone loss and consequent fracture and should be actively considered for prophylaxis. Based upon available evidence, the rank order of choice for prophylaxis would be a bisphosphonate followed by vitamin D. For established glucocorticoid induced osteoporosis, parathyroid hormone followed by a bisphosphonate appears useful.

Conclusions:  Glucocorticoid‐induced bone loss can be effectively prevented or reversed.
Magnitude of CD8+ T‐cell responses against hepatitis C virus and severity of hepatitis do not necessarily determine outcomes in acute hepatitis C virus infection
Authors: Doi Hiroyoshi , Hiroishi Kazumasa , Shimazaki Tomoe , Eguchi Junichi , Baba Toshiyuki , Ito Takayoshi , Matsumura Takuya , Nozawa Hisako , Morikawa Kenichi , Ishii Shigeaki , Hiraide Ayako , Sakaki Masashi , Imawari Michio
Published: November 2008

Aim:  We investigated the relationship between the magnitude of comprehensive hepatitis C virus (HCV)‐specific CD8+ T‐cell responses and the clinical course of acute HCV infection.

Methods:  Six consecutive patients with acute HCV infection were studied. Analysis of HCV‐specific CD8+ T‐cell responses was performed using an interferon‐γ‐based enzyme‐linked immunospot assay using peripheral CD8+ T‐cells, monocytes and 297 20‐mer synthetic peptides overlapping by 10 residues and spanning the entire HCV sequence of genotype 1b.

Results:  Five patients presented detectable HCV‐specific CD8+ T‐cell responses against a single and different peptide, whereas 1 patient showed responses against three different peptides. Neither the magnitude of HCV‐specific CD8+ T‐cell responses nor the severity of hepatitis predicts the outcome of acute hepatitis. The maximum number of HCV‐specific CD8+ T‐cells correlated with maximum serum alanine aminotransferase level during the course (r = 0.841, P = 0.036).

Conclusions:  HCV‐specific CD8+ T‐cell responses were detectable in all 6 patients with acute HCV infection, and 6 novel HCV‐specific CTL epitopes were identified. Acute HCV infection can resolve with detectable HCV‐specific CD8+ T‐cell responses, but without development of antibody against HCV.
Kinase‐dependent modification of dendritic excitability after long‐term potentiation
Authors: Rosenkranz J. Amiel , Frick Andreas , Johnston Daniel
Published: November 2008

Patterns of presynaptic activity properly timed with postsynaptic action potential output can not only increase the strength of synaptic inputs but can also increase the excitability of dendritic branches of adult CA1 pyramidal neurons. Here, we examined the role of protein kinase A (PKA) and mitogen‐activated protein kinase (MAPK) in the enhancement of dendritic excitability that occurs during theta‐burst pairing of presynaptic and postsynaptic firing activity. Using dendritic and somatic whole‐cell recordings in rat hippocampal slices, we measured the increase in the amplitude of back‐propagating action potentials in the apical dendrite that occurs in parallel with long‐term potentiation (LTP) of synaptic inputs. We found that inhibition of the MAPK pathway prevents this enhancement of dendritic excitability using either a weak or strong LTP induction protocol, while synaptic LTP can still be induced by the strong protocol. Both forms of plasticity are blocked by inhibition of PKA and occluded by interfering with cAMP degradation, consistent with a PKA‐mediated increase in MAPK activity following induction of LTP. This provides a signalling mechanism for plasticity of dendritic excitability that occurs during neuronal activity and demonstrates the necessity of MAPK activation. Furthermore, this study uncovers an additional contribution of kinase activation to plasticity that may occur during learning.
Age‐related differences in the dose–response relationship of muscle protein synthesis to resistance exercise in young and old men
Authors: Kumar Vinod , Selby Anna , Rankin Debbie , Patel Rekha , Atherton Philip , Hildebrandt Wulf , Williams John , Smith Kenneth , Seynnes Olivier , Hiscock Natalie , Rennie Michael J.
Published: November 2008

We investigated how myofibrillar protein synthesis (MPS) and muscle anabolic signalling were affected by resistance exercise at 20–90% of 1 repetition maximum (1 RM) in two groups (25 each) of post‐absorptive, healthy, young (24 ± 6 years) and old (70 ± 5 years) men with identical body mass indices (24 ± 2 kg m−2). We hypothesized that, in response to exercise, anabolic signalling molecule phosphorylation and MPS would be modified in a dose‐dependant fashion, but to a lesser extent in older men. Vastus lateralis muscle was sampled before, immediately after, and 1, 2 and 4 h post‐exercise. MPS was measured by incorporation of [1,2‐13C] leucine (gas chromatography–combustion–mass spectrometry using plasma [1,2‐13C]α‐ketoisocaparoate as surrogate precursor); the phosphorylation of p70 ribosomal S6 kinase (p70s6K) and eukaryotic initiation factor 4E binding protein 1 (4EBP1) was measured using Western analysis with anti‐phosphoantibodies. In each group, there was a sigmoidal dose–response relationship between MPS at 1–2 h post‐exercise and exercise intensity, which was blunted (P < 0.05) in the older men. At all intensities, MPS fell in both groups to near‐basal values by 2–4 h post‐exercise. The phosphorylation of p70s6K and 4EBP1 at 60–90% 1 RM was blunted in older men. At 1 h post‐exercise at 60–90% 1 RM, p70s6K phosphorylation predicted the rate of MPS at 1–2 h post‐exercise in the young but not in the old. The results suggest that in the post‐absorptive state: (i) MPS is dose dependant on intensity rising to a plateau at 60–90% 1 RM; (ii) older men show anabolic resistance of signalling and MPS to resistance exercise.
Blunted Akt/FOXO signalling and activation of genes controlling atrophy and fuel use in statin myopathy
Authors: Mallinson Joanne E. , Constantin‐Teodosiu Dumitru , Sidaway James , Westwood F. Russell , Greenhaff Paul L.
Published: November 2008

Statins are used clinically for cholesterol reduction, but statin therapy is associated with myopathic changes through a poorly defined mechanism. We used anin vivomodel of statin myopathy to determine whether statins up‐regulate genes associated with proteasomal‐ and lysosomal‐mediated proteolysis and whether PDK gene expression is simultaneously up‐regulated leading to the impairment of muscle carbohydrate oxidation. Animals were dosed daily with 80 mg kg−1day−1simvastatin for 4 (n= 6) and 12 days (n= 5), 88 mg kg−1day−1simvastatin for 12 days (n= 4), or vehicle (0.5% w/v hydroxypropyl‐methylcellulose and 0.1% w/v polysorbate 80; Control,n= 6) for 12 days by oral gavage. We found, in biceps femoris muscle, decreased AktSer473, FOXO1Ser253and FOXO3aSer253phosphorylation in the cytosol (P< 0.05,P< 0.05,P< 0.001, respectively) and decreased phosphorylation of FOXO1 in the nucleus after 12 days simvastatin when compared to Control (P< 0.05). This was paralleled by a marked increase in the transcription of downstream targets of FOXO, i.e. MAFbx (P< 0.001), MuRF‐1 (P< 0.001), cathepsin‐L (P< 0.05), PDK2 (P< 0.05) and PDK4 (P< 0.05). These changes were accompanied by increased PPARα (P< 0.05), TNFα (P< 0.01), IL6 (P< 0.01), Mt1A (P< 0.01) mRNA and increased muscle glycogen (P< 0.05) compared to Control. RhoA activity decreased after 4 days simvastatin (P< 0.05); however, activity was no different from Control after 12 days. Simvastatin down‐regulated PI3k/Akt signalling, independently of RhoA, and up‐regulated FOXO transcription factors and downstream gene targets known to be implicated in proteasomal‐ and lysosomal‐mediated muscle proteolysis, carbohydrate oxidation, oxidative stress and inflammation in anin vivomodel of statin‐induced myopathy. These changes occurred in the main before evidence of extensive myopathy or a decline in the muscle protein to DNA ratio.
Mechanisms of Strain-Mediated Mesenchymal Stem Cell Apoptosis
Authors: Kearney E. M. , Prendergast P. J. , Campbell V. A.
Published: November 2008

Mechanical conditioning of mesenchymal stem cells (MSCs) has been adopted widely as a biophysical signal to aid tissue engineering applications. The replication of in vivo mechanical signaling has been used in in vitro environments to regulate cell differentiation, and extracellular matrix synthesis, so that both the chemical and mechanical properties of the tissue-engineered construct are compatible with the implant site. While research in these areas contributes to tissue engineering, the effects of mechanical strain on MSC apoptosis remain poorly defined. To evaluate the effects of uniaxial cyclic tensile strain on MSC apoptosis and to investigate mechanotransduction associated with strain-mediated cell death, MSCs seeded on a 2D silicone membrane were stimulated by a range of strain magnitudes for 3days. Mechanotransduction was investigated using the stretch-activated cation channel blocker gadolinium chloride, the L-type voltage-activated calcium channel blocker nicardipine, the c-jun NH2-terminal kinase (JNK) blocker D-JNK inhibitor 1, and the calpain inhibitor MDL 28170. Apoptosis was assessed through DNA fragmentation using the terminal deoxynucleotidyl transferase mediated-UTP-end nick labeling method. Results demonstrated that tensile strains of 7.5% or greater induce apoptosis in MSCs. L-type voltage-activated calcium channels coupled mechanical stress to activation of calpain and JNK, which lead to apoptosis through DNA fragmentation. The definition of the in vitro boundary conditions for tensile strain and MSCs along with a proposed mechanism for apoptosis induced by mechanical events positively contributes to the development of MSC biology, bioreactor design for tissue engineering, and development of computational methods for mechanobiology.
Microscale Diffusion Properties of the Cartilage Pericellular Matrix Measured Using 3D Scanning Microphotolysis
Authors: Leddy Holly A. , Christensen Susan E. , Guilak Farshid
Published: November 2008

Chondrocytes, the cells in articular cartilage, are enclosed within a pericellular matrix (PCM) whose composition and structure differ from those of the extracellular matrix (ECM). Since the PCM surrounds each cell, molecules that interact with the chondrocyte must pass through the pericellular environment. A quantitative understanding of the diffusional properties of the PCM may help in elucidating the regulatory role of the PCM in controlling transport to and from the chondrocyte. The diffusivities of fluorescently labeled 70 kDa and 500 kDa dextrans were quantified within the PCM of porcine articular cartilage using a newly developed mathematical model of scanning microphotolysis (SCAMP). SCAMP is a rapid line photobleaching method that accounts for out-of-plane bleaching attributable to high magnification. Data were analyzed by a best-fit comparison to simulations generated using a discretization of the diffusion-reaction equation in conjunction with the microscope-specific three-dimensional excitation and detection profiles. The diffusivity of the larger molecule (500 kDa dextran) was significantly lower than that of the smaller molecule (70 kDa dextran), and values were consistent with those reported previously using standard techniques. Furthermore, for both dextran sizes, the diffusion coefficient was significantly lower in the PCM than in the ECM; however, this difference was not detected in early-stage arthritic tissue. We have successfully modified the SCAMP technique to measure diffusion coefficients within the small volume of the PCM using confocal laser scanning microscopy. Our results support the hypothesis that diffusivity within the PCM of healthy articular cartilage is lower than that within the ECM, presumably due to differences in proteoglycan content.
A “Hydrokinematic” Method of Measuring the Glide Efficiency of a Human Swimmer
Authors: Naemi Roozbeh , Sanders Ross H.
Published: November 2008

The aim of this study was to develop and test a method of quantifying the glide efficiency, defined as the ability of the body to maintain its velocity over time and to minimize deceleration through a rectilinear glide. The glide efficiency should be determined in a way that accounts for both the inertial and resistive characteristics of the gliding body as well as the instantaneous velocity. A displacement function (parametric curve) was obtained from the equation of motion of the body during a horizontal rectilinear glide. The values of the parameters in the displacement curve that provide the best fit to the displacement-time data of a body during a rectilinear horizontal glide represent the glide factor and the initial velocity of the particular glide interval. The glide factor is a measure of glide efficiency and indicates the ability of the body to minimize deceleration at each corresponding velocity. The glide efficiency depends on the hydrodynamic characteristic of the body, which is influenced by the body’s shape as well as by the body’s size. To distinguish the effects of size and shape on the glide efficiency, a size-related glide constant and a shape-related glide coefficient were determined as separate entities. The glide factor is the product of these two parameters. The goodness of fit statistics indicated that the representative displacement function found for each glide interval closely represents the real displacement data of a body in a rectilinear horizontal glide. The accuracy of the method was indicated by a relative standard error of calculation of less than 2.5%. Also the method was able to distinguish between subjects in their glide efficiency. It was found that the glide factor increased with decreasing velocity. The glide coefficient also increased with decreasing Reynolds number. The method is sufficiently accurate to distinguish between individual swimmers in terms of their glide efficiency. The separation of glide factor to a size-related glide constant and a shape-related glide coefficient enabled the effect of size and shape to be quantified.
The Salty Science of the Aluminum-Air Battery
Authors: Chasteen Stephanie V. , Chasteen N. Dennis , Doherty Paul
Published: November 2008

Fruit batteries and saltwater batteries are excellent ways to explore simple circuits in the classroom. These are examples of air batteries1 in which metal reacts with oxygen in the air in order to generate free electrons, which flow through an external circuit and do work. Students are typically told that the salt or fruit water acts as an electrolyte to bring electrons from the anode to the cathode. That's true, but it leaves the battery as a black box. Physics teachers often don't have the background to explain the chemistry behind these batteries. We've written this paper to explore the electrochemistry behind an air battery using copper cathode, aluminum anode, and saltwater.
Photosynthetic Control of Atmospheric Carbonyl Sulfide During the Growing Season
Authors: Campbell J. E. , Carmichael G. R. , Chai T. , Mena-Carrasco M. , Tang Y. , Blake D. R. , Blake N. J. , Vay S. A. , Collatz G. J. , Baker I. , Berry J. A. , Montzka S. A. , Sweeney C. , Schnoor J. L. , Stanier C. O.
Published: November 2008

Climate models incorporate photosynthesis-climate feedbacks, yet we lack robust tools for large-scale assessments of these processes. Recent work suggests that carbonyl sulfide (COS), a trace gas consumed by plants, could provide a valuable constraint on photosynthesis. Here we analyze airborne observations of COS and carbon dioxide concentrations during the growing season over North America with a three-dimensional atmospheric transport model. We successfully modeled the persistent vertical drawdown of atmospheric COS using the quantitative relation between COS and photosynthesis that has been measured in plant chamber experiments. Furthermore, this drawdown is driven by plant uptake rather than other continental and oceanic fluxes in the model. These results provide quantitative evidence that COS gradients in the continental growing season may have broad use as a measurement-based photosynthesis tracer.
Novel Nucleotide Human Immunodeficiency Virus Reverse Transcriptase Inhibitor GS-9148 with a Low Nephrotoxic Potential: Characterization of Renal Transport and Accumulation
Authors: Cihlar Tomas , LaFlamme Genevieve , Fisher Robyn , Carey Anne C. , Vela Jennifer E. , Mackman Richard , Ray Adrian S.
Published: November 2008

Accumulation of antiviral nucleotides in renal proximal tubules is controlled by their basolateral uptake via the human renal organic anion transporters type 1 (hOAT1) and 3 (hOAT3) and apical efflux via the multidrug resistance protein 4 (MRP4). GS-9148 is a novel ribose-modified nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitor, and its oral prodrug GS-9131 is currently being evaluated in the clinic as an anti-HIV agent. To assess the potential of GS-9148 for nephrotoxicity, its mechanism of renal transport, cytotoxicity, and renal accumulation were explored in vitro and in vivo. In comparison with the acyclic nucleotides cidofovir, adefovir, and tenofovir, GS-9148 showed 60- to 100-fold lower efficiency of transport (Vmax/Km) by hOAT1 and was 20- to 300-fold less cytotoxic in cells overexpressing hOAT1, indicating its lower hOAT1-mediated intracellular accumulation and reduced intrinsic cytotoxicity. GS-9148 was also relatively inefficiently transported by hOAT3. Similar to acyclic nucleotides, GS-9148 was a substrate for MRP4 as evidenced by its reduced intracellular retention in cells overexpressing the efflux pump. Consistent with these molecular observations, GS-9148 was inefficiently taken up by fresh human renal cortex tissue in vitro and showed a limited accumulation in kidneys in vivo following oral administration of [14C]GS-9131 to dogs. Compared to acyclic nucleotide analogs, GS-9148 was also found to have lower net active tubular secretion in dogs. Collectively, these results suggest that GS-9148 exhibits a low potential for renal accumulation and nephrotoxicity.
Dynamics of the Cytokine Response toMycobacterium ulceransduring Antibiotic Treatment forM. ulceransDisease (Buruli Ulcer) in Humans
Authors: Sarfo F. S. , Phillips R. O. , Ampadu E. , Sarpong F. , Adentwe E. , Wansbrough-Jones M.
Published: November 2008

We have studied the evolution of the gamma interferon (IFN-γ) and interleukin 10 (IL-10) responses afterMycobacterium ulceranssonicate stimulation of whole blood from patients with earlyM. ulceranslesions during treatment with rifampin and streptomycin for 8 weeks. Among the 26 patients, secretion of IFN-γ increased during treatment, with a significant increase at 4 weeks and a further increase after 8 weeks overall. The increase was more rapid in patients with large or ulcerative lesions, becoming significant by 4 weeks. For small lesions, there was only a minor increase, which did not reach significance. There was no significant change in the median IL-10 response during antibiotic therapy, and there was no inverse correlation between IFN-γ and IL-10 responses. These results demonstrate that an IFN-γ secretory response toM. ulceransdeveloped, independently of IL-10 secretion, in patients whoseM. ulceransdisease healed during antibiotic therapy.