Stock-recruitment relationships of the tiger prawns (Penaeus esculentus and Penaeus semisulcatus) in the Australian Northern Prawn Fishery

This paper investigates the stock-recruitment and equilibrium yield dynamics for the two species of tiger prawns (Penaeus esculentus and Penaeus semisulcatus) in Australia's most productive prawn fishery: the Northern Prawn Fishery. Commercial trawl logbooks for 1970-93 and research surveys are used to develop population models for these prawns. A population model that incorporates continuous recruitment is developed. Annual spawning stock and recruitment indices are then estimated from the population model. Spawning stock indices represent the abundance of female prawns that are likely to spawn; recruitment indices represent the abundance of all prawns less than a certain size. The relationships between spawning stock and subsequent recruitment (SRR), between recruitment and subsequent spawning stock (RSR), and between recruitment and commercial catch were estimated through maximum-likelihood models that incorporated autoregressive terms. Yield as a function of fishing effort was estimated by constraining to equilibrium the SRR and RSR. The resulting production model was then used to determine maximum sustainable yield (MSY) and its corresponding fishing effort (f(MSY)). Long-term yield estimates for the two tiger prawn species range between 3700 and 5300 t. The fishing effort at present is close to the level that should produce MSY for both species of tiger prawns. However, current landings, recruitment and spawning stock are below the equilibrium values predicted by the models. This may be because of uncertainty in the spawning stock-recruitment relationships, a change in carrying capacity, biased estimates of fishing effort, unreliable catch statistics, or simplistic assumptions about stock structure. Although our predictions of tiger prawn yields are uncertain, management will soon have to consider new measures to counteract the effects of future increases in fishing effort.

Detection and progression of chronic allograft nephropathy : A study based on protocol biopsies

Background. Kidney transplantation (KTX) is considered to be the best treatment of terminal uremia. Despite improvements in short-term graft survival, a considerable number of kidney allografts are lost due to the premature death of patients with a functional kidney and to chronic allograft nephropathy (CAN). Aim. To investigate the risk factors involved in the progression of CAN and to analyze diagnostic methods for this entity. Materials and methods. Altogether, 153 implant and 364 protocol biopsies obtained between June 1996 and April 2008 were analyzed. The biopsies were classified according to Banff ’97 and chronic allograft damage index (CADI). Immunohistochemistry for TGF-β1 was performed in 49 biopsies. Kidney function was evaluated by creatinine and/or cystatin C measurement and by various estimates of glomerular filtration rate (GFR). Demographic data of the donors and recipients were recorded after 2 years’ follow-up. Results. Most of the 3-month biopsies (73%) were nearly normal. The mean CADI score in the 6-month biopsies decreased significantly after 2001. Diastolic hypertension correlated with ΔCADI. Serum creatinine concentration at hospital discharge and glomerulosclerosis were risk factors for ΔCADI. High total and LDL cholesterol, low HDL and hypertension correlated with chronic histological changes. The mean age of the donors increased from 41 -52 years. Older donors were more often women who had died from an underlying disease. The prevalence of delayed graft function increased over the years, while acute rejections (AR) decreased significantly over the years. Sub-clinical AR was observed in 4% and it did not affect long-term allograft function or CADI. Recipients´ drug treatment was modified along the Studies, being mycophenolate mophetil, tacrolimus, statins and blockers of the renine-angiotensin-system more frequently prescribed after 2001. Patients with a higher ΔCADI had lower GFR during follow-up. CADI over 2 was best predicted by creatinine, although with modest sensitivity and specificity. Neither cystatin C nor other estimates of GFR were superior to creatinine for CADI prediction. Cyclosporine A toxicity was seldom seen. Low cyclosporin A concentration after 2 h correlated with TGF- β1 expression in interstitial inflammatory cells, and this predicted worse graft function. Conclusions. The progression of CAN has been affected by two major factors: the donors’ characteristics and the recipients’ hypertension. The increased prevalence of DGF might be a consequence of the acceptance of older donors who had died from an underlying disease. Implant biopsies proved to be of prognostic value, and they are essential for comparison with subsequent biopsies. The progression of histological damage was associated with hypertension and dyslipidemia. The augmented expression of TGF-β1 in inflammatory cells is unclear, but it may be related to low immunosuppression. Serum creatinine is the most suitable tool for monitoring kidney allograft function on every-day basis. However, protocol biopsies at 6 and 12 months predicted late kidney allograft dysfunction and affected the clinical management of the patients. Protocol biopsies are thus a suitable surrogate to be used in clinical trials and for monitoring kidney allografts.

Extraordinary high strain rate superplasticity in electrodeposited nano-nickel and alloys

Superplastic materials exhibit very large elongations to failure,typically >500%, and this enables commercial forming of complex shaped components at slow strain rates of similar to 10(-4) s(-1). We report extraordinary record superplastic elongations to failure of up to 5300% at both high strain rates and low temperature in electrodeposited nanocrystalline Ni and some Ni alloys. Superplasticity is not related to the presence of sulfur or a low melting phase at grain boundaries. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Lysis dynamics and membrane oligomerization pathways for Cytolysin A (ClyA) pore-forming toxin

Pore-forming toxins are known for their ability to efficiently form transmembrane pores which eventually leads to cell lysis. The dynamics of lysis and underlying self-assembly or oligomerization pathways leading to pore formation are incompletely understood. In this manuscript the pore-forming kinetics and lysis dynamics of Cytolysin-A (ClyA) toxins on red blood cells (RBCs) are quantified and compared with experimental lysis data. Lysis experiments are carried out on a fixed mass of RBCs, under isotonic conditions in phosphate-buffered saline, for different initial toxin concentrations ranging from 2.94-14.7 nM. Kinetic models which account for monomer binding, conformation and oligomerization to form the dodecameric ClyA pore complex are developed and lysis is assumed to occur when the number of pores per RBC (n(p)) exceeds a critical number, n(pc). By analysing the model in a sublytic regime (n(p) < n(pc)) the number of pores per RBC to initiate lysis is found to lie between 392 and 768 for the sequential oligomerization mechanism and between 5300 and 6300 for the non-sequential mechanism. Rupture rates which are first order in the number of RBCs are seen to provide the best agreement with the lysis experiments. The time constants for pore formation are estimated to lie between 1 and 20 s and monomer conformation time scales were found to be 2-4 times greater than the oligomerization times. Cell rupture takes places in 100s of seconds, and occurs predominantly with a steady number of pores ranging from 515 to 11 000 on the RBC surface for the sequential mechanism. Both the sequential irreversible and non-sequential kinetics provide similar predictions of the hemoglobin release dynamics, however the hemoglobin released as a function of the toxin concentration was accurately captured only with the sequential model. Each mechanism develops a distinct distribution of mers on the surface, providing a unique experimentally observable fingerprint to identify the underlying oligomerization pathways. Our study offers a method to quantify the extent and dynamics of lysis which is an important aspect of developing novel drug and gene delivery strategies based on pore-forming toxins.

Variational approach to the closure problem of turbulence theory

A new method is proposed to solve the closure problem of turbulence theory and to drive the Kolmogorov law in an Eulerian framework. Instead of using complex Fourier components of velocity field as modal parameters, a complete set of independent real parameters and dynamic equations are worked out to describe the dynamic states of a turbulence. Classical statistical mechanics is used to study the statistical behavior of the turbulence. An approximate stationary solution of the Liouville equation is obtained by a perturbation method based on a Langevin-Fokker-Planck (LFP) model. The dynamic damping coefficient eta of the LFP model is treated as an optimum control parameter to minimize the error of the perturbation solution; this leads to a convergent integral equation for eta to replace the divergent response equation of Kraichnan's direct-interaction (DI) approximation, thereby solving the closure problem without appealing to a Lagrangian formulation. The Kolmogorov constant Ko is evaluated numerically, obtaining Ko = 1.2, which is compatible with the experimental data given by Gibson and Schwartz, (1963).

A tool for better management of water quality during periods of algal blooms: the case of the River Oise

Like other rivers in the Paris area, the Oise is subject to important seasonal algal blooms. This eutrophication generates notable problems for the production of drinking-water from a treatment plant on the river at Méry. A mathematical model has been developed to simulate variation in water quality in a pre-treatment storage basin, and another model is currently being adapted to model the River Oise. Integration of the two models should provide a comprehensive tool for predicting variations of phytoplankton and water-quality parameters associated with algal blooms. This will be a decision-aid for optimizing control of the treatment process for providing potable water.

Charge and spin transport in graphene devices

170 p.

La pêche artisanale en lagune Aby-Tendo-Ehy (Côte d'Ivoire): premières estimations de la production

This work is the result of one year of investigations on the artisanal fisheries of the Aby-Tendo-Ehy lagoon. The structure of fish catches varies with the fisheries zones and the fishing gears, but is relatively stable all year along, in the spite of the existence of some species with well worked seasonary cycle. The composition of beach seines catches, which are relatively unselective fishing gears, is: - in the Tendo lagoon (oligohaline) and Ehy lagoon (freshwater): Chrysichthys spp. 35.1%, Tilapia spp. 18.9%, Acentrogobius schlegelii 15.7%, Ethmalosa fimbriata 12% (those are two seasonary species), Tylochromis jentinki 8.8%, Elops lacerta 5.6%, other species 3.9%. - in the south of the Aby lagoon, under tide influence, Ethmalosa fimbriata 79%, Elops lacerta 12%, Chrysichthys spp. 6%, other species 3%. A preliminary estimation of 7900 tons for this lagoon artisanal fisheries total production is made for 1979 (from representative fishing villages) and can be shared as follows: - beach seines: 5300 tons; - purse seines and "syndicat" seines: 2600 tons; individual fishing: not estimated, it mostly concerns fill nets.

O Programa de Agentes Comunitários de Saúde adaptado à cidade do Rio de Janeiro: uma análise das suas concepções

Este trabalho trata de um estudo sobre uma experiência de adaptação do modelo Programa de Agentes Comunitários de Saúde, executado pela Coordenação de Saúde da Comunidade, da Secretaria Municipal de Saúde do Rio de Janeiro, no período de 2002 a 2005, que se coloca com certa divergência ao projeto político do Ministério da Saúde. Propõe-se a apresentar o contexto em que surge essa proposta e identificar e analisar as concepções da sua formulação. Poucos foram os documentos oficiais disponíveis para este estudo, transformando as entrevistas na técnica primordial para a realização do mesmo. Verificamos que havia um vazio de formulação de uma política de mudança da atenção básica para a cidade e, dessa forma, a oportunidade para formulações técnicas de modelos experimentais se colocou. Nesse cenário, surge a proposta da implantação de equipes de PACS, como uma tentativa de dar resposta aos obstáculos colocados à expansão da ESF, sendo aproveitado para ser adaptado de forma a aumentar a oferta de ações da atenção básica, nas áreas consideradas estratégicas pela NOAS 01/01.

凤眼莲根区异养细菌的群落特征与异养活性的研究

本文研究了凤眼莲根区(根际与根面)异养细菌的群落特征与异养活性。从根区分离出24株优势菌,经鉴定有10个属。其中以气单胞菌属、微球菌属、假单胞菌属、土壤杆菌属和芽孢杆菌属为主要菌属。细菌总数:根际>根面>水体。异养活性以氧化葡萄糖的速率计算。在30℃和pH7.0的条件下。根区菌群都显示较高的活性,且按下列顺序增强:老根区菌群>幼根区菌群>枯根区菌群;而根面菌群活性均大于根际菌群。但在10℃和pH5.0、8.6时,其活性明显地受到抑制。

单晶硅中铒点缺陷及Er-O复合缺陷电子结构的EHMO计算

本文采用集团模型和推广的Hucket分子轨道理论(EHMO)计算c-Si中Er点缺陷及Er-O复合缺陷的原子构型及电子结构。计算结果符合实验及一些文献的第一性原理计算结果,解释了Er有c-Si中的发光特性。

关于国家自然科学基金生物力学学科优先资助领域的思考

<正>作为我国基础研究最重要的资助机构之一,国家自然科学基金委员会自成立伊始即大力扶持生物力学新兴学科发展、培养和造就生物力学专业人才、推动生物力学研究基地建设,成绩斐然。在科学发展至二十一世纪的今天,针对国际生物力学领域及相关学科发展动态、国家中长期科技发展规划、以及生物力学学科

内蒙古岱海DH99a岩芯沉积物碳含量变化与湖区全新世气候变迁

Daihai Lake, a graben-type closed lake, lies ca. 10 km east of Liangcheng County, Inner Mongolia, north-central China. For its location at the transition of semi-humid and semi-arid areas, and in the north edge of the East Asian monsoon, the lake is sensitive to changes in climate and environment. Based on analyses of total inorganic carbon (TIC), total organic carbon (TOC) and the ratio of total organic carbon to total nitrogen (C/N ratio) of DH99a core sediments recovered in the central part of Daihai Lake, the data suggest Holocene climatic history of the lake region is reconstructed. In this paper, the TIC and TOC contents of the lake sediments are closely related to climate changes. 1) Changes in TIC content of the lake sediments is closely related to climate, which directly reflect changes of temperature in the lake region, i.e., higher TIC content is linked with warmer temperature and stronger evaporation; 2) Changes in TOC and C/N ratio reflect the regional precipitation, i.e., relatively higher TOC content and C/N ratio indicate higher rainfall which results in stronger river flow and more organic matter entering into the lake. Data of the TIC content, TOC content and C/N ratio of DH99a core sediments suggest that climatic history of the Daihai Lake region is characterized by 4 stages. During the interval of ca. 11200-7500 a BP, higher TIC content, relatively lower TOC content and C/N ratio value indicate a warmer and slight dry condition over the lake area. From ca. 7500 to 4500 a BP, high values of TIC content, with an increase in TOC content and C/N ratio suggest the climate was warm and humid. Changes of TIC content, TOC content show that both temperature and precipitation displayed obvious fluctuations during the period, i.e., slightly cool and humid ca. 7500-6700 a BP, warm and moist ca. 6700-5300a BP, mild and comparatively humid ca. 5300-4500a BP. Between ca. 4500 and 2900 a BP, TIC content and TOC content decreased gradually while fluctuating, C/N ratio displayed a decreasing trend. These data imply that the climate generally became cooler and drier than the preceding period. The lowest values of TIC content, TOC content and C/N ratio during the interval of ca. 2900-0 a BP, demonstrate that the climate was severe, and became cool and dry. However the relative higher values of TIC content, TOC content and C/N ratio between ca. 1700 and 1300 a BP may denote an increase both in temperature and in precipitation. Data of TIC content, TOC content and C/N ratio in Daihai DH99a core sediments indicate that the warm period was asynchronous with the humid time, the warm interval began in ca. 11200 a BP, and ended in ca. 2900 a BP. The humid period was ca. 7500-2900 a BP. During ca. 7500^500 a BP, the climate was warm and humid, which was the climatic optimum of the Holocene Epoch in the Daihai Lake region. Data of TIC content, TOC content and C/N ratio in Daihai DH99a core sediments imply that the Holocene climate was unstable, the fluctuating events happened occasionally. Such as the cold and dry climate in ca. 4400-4200a BP, the warm and humid climatic condition in the period between ca.1700 and 1300a BP.

Ag/SiO2: A novel catalyst with high activity and selectivity for hydrogenation of chloronitrobenzenes

Ag/SiO2 prepared by an in situ reduction method are found, for the first time, to be highly effective and recyclable catalysts for the selective hydrogenation of a range of chloronitrobenzes to their corresponding chloroanilines, which are of great potential as industrially viable and cheap novel catalysts for the production of chloroanilines.