Continuous harvesting costs in sole-owner fisheries with increasing marginal returns

We develop a bioeconomic model to analyze a sole-owner fishery with fixed costs as well as a continuous cost function for the generalized Cobb-Douglas production function with increasing marginal returns to effort level. On the basis of data from the North Sea herring fishery, we analyze the consequences of the combined effects of increasing marginal returns and fixed costs. We find that regardless of the magnitude of the fixed costs, cyclical policies can be optimal instead of the optimal steady state equilibrium advocated in much of the existing literature. We also show that the risk of stock collapse increases significantly with increasing fixed costs as this implies higher period cycles which is a quite counterintuitive result as higher costs usually are considered to have a conservative effect on resources.Bioeconomic modelling; Stock collapse; Fixed costs; Pulse fishing; Cyclical dynamics; Increasing marginal returns

Deterministic Population Dynamics of Fish Stocks at Low Population Sizes: A Parametric Spline Approach

We develop a methodological approach using splines to analyze the deterministic population dynamics of fish stocks at low stock levels. Considering the aggregate Northern cod stock by way of illustration, we reject the hypothesis of strong compensation estimated by the conventional regression methods used by classic bioeconomic models

Parenteral administration of factor Xa/IIa inhibitors limits experimental aortic aneurysm and atherosclerosis

Intraluminal thrombus is a consistent feature of human abdominal aortic aneurysm (AAA). Coagulation factor Xa (FXa) catalyses FII to thrombin (FIIa). We examined the effect of FXa/FIIa inhibition on experimental aortic aneurysm in apolipoprotein E-deficient (ApoE−/−) mice infused with angiotensin II (AngII). The concentration of FXa within the supra-renal aorta (SRA) correlated positively with SRA diameter. Parenteral administration of enoxaparin (FXa/IIa inhibitor) and fondaparinux (FXa inhibitor) over 14 days reduced to severity of aortic aneurysm and atherosclerosis in AngII-infused ApoE−/− mice. Enteral administration of the FIIa inhibitor dabigatran had no significant effect. Aortic protease-activated receptor (PAR)-2 expression increased in response to AngII infusion. Fondaparinux reduced SRA levels of FXa, FIIa, PAR-2, matrix metalloproteinase (MMP)2, Smad2/3 phosphorylation,and MOMA-2 positive cells in the mouse model. FXa stimulated Smad2/3 phosphorylation and MMP2 expression in aortic vascular smooth muscle cells (VSMC) in vitro. Expression of MMP2 in FXastimulated VSMC was downregulated in the presence of a PAR-2 but not a PAR-1 inhibitor. These findings suggest that FXa/FIIa inhibition limits aortic aneurysm and atherosclerosis severity due to down-regulation of vascular PAR-2-mediated Smad2/3 signalling and MMP2 expression. Inhibition of FXa/FIIa may be a potential therapy for limiting aortic aneurysm

Funding approaches for mental health services : Is there still a role for clustering?

Funding for mental health services in England faces many challenges including operating under financial constraints where it is not easy to demonstrate the link between activity and funding. Mental health services need to operate alongside and collaborate with acute hospital services where there is a well-established system for paying for activity. The funding landscape is shifting at a rapid pace and we outline the distinctions between the three main options – block contracts, episodic payment and capitation. Classification of treatment episodes via clustering presents an opportunity to demonstrate activity and reward it within these payment approaches. We have been engaged in research to assess how well the clustering system is performing against a number of fundamental criteria. Clusters need to be reliably recorded, to correspond to health needs, and to treatments that require roughly similar resources. We find that according to these criteria, clusters are falling short of providing a sound basis for measuring and financing services. Yet, we argue, it is the best available option and is essential for a more transparent funding approach for mental health to demonstrate its claim on resources, and that, as such, clusters should be a starting point for evolving a better funding system

Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants

Open Access article - can be viewed online without a subscription at: http://dx.doi.org/doi:10.1186/1471-2229-11-83Background: In plants, nitrate (NO3 -) nutrition gives rise to a natural N isotopic signature (δ15N), which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4 +) nutrition. When NH4 + is the major N source, the two forms, NH4 + and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g) and NH4 + (aq) which drives to a different δ15N. Nine plant species with different NH4 +-sensitivities were cultured hydroponically with NO3 - or NH4 + as the sole N sources, and plant growth and δ15N were determined. Short-term NH4 +/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form) were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4 + and NH3. Results: Several NO3 --fed plants were consistently enriched in 15N, whereas plants under NH4 + nutrition were depleted of 15N. It was shown that more sensitive plants to NH4 + toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4 + showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4 + pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. Conclusions: This article proposes that the negative values of δ15N in NH4 +-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4 +/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4 + may have two components: one that transports N in the molecular form and is associated with fractionation and another that transports N in the ionic form and is not associated with fractionatio

Cognitive Reserve Characteristics and Occupational Performance Implications in People with Mild Cognitive Impairment

The Cognitive Reserve hypothesis suggests that there are individual differences in the ability to cope with the pathologic changes in Alzheimer’s Disease. The proportion of elderly individuals has increased in recent years; this increase emphasizes the importance of early detection of mild cognitive impairment and the promotion of healthy ageing. The purpose of our study is to characterize cognitive reserve and occupational performance implications in people with mild cognitive impairment. 125 patients with mild cognitive impairment were enrolled. The Montreal Cognitive Assessments (MoCA) was used to evaluate cognitive status and the Cognitive Reserve Index Questionnaire (CRIq) as an indicator of cognitive reserve. Higher level of education was associated with higher MoCA scores (r = 0.290, p = 0.001). Positive significant correlations were observed between MoCA and total CRIq (r = 0.385, p < 0.001) as well as its three sub-domains, education (r = 0.231, p = 0.010), working activity (r = 0.237, p = 0.008) and leisure time (r = 0.319, p < 0.001). This study findings provide the importance of considering socio-behavioral factors in cognitive status. This research helps to describe the importance of engaging occupationally along the whole life-course as a potential protective factor in ageing, and includes a perspective of occupational therapy regarding the hypothesis of cognitive reserve.Depto. de EnfermeríaFac. de Enfermería, Fisioterapia y PodologíaTRUEpu

Immunogenicity of Trivalent Inactivated Influenza Vaccination Received During Pregnancy or Postpartum

To estimate the effects of gestational age and other maternal factors on immunologic responses to influenza vaccination