The politics of a new legal order for fisheries

Illegal, unreported, and unregulated (IUU) Fishing is considered a major threat to high seas fish stocks. Each of the the international regional fishery management organizations (RFMOs) are combating some form of IUU fishing and this led the Food and Agriculture Oranization of the United Nations (FAO) to adopt the International Plan of Action to Deter, Prevent and Eliminate IUU Fishing (IPOA-IUU). This article will analyze the issues involved with IUU fishing, examine the recommendations in the IPOA, and consider examples of successful management and enforcement measures in use by states and RFMOs. Finally, recent developments in China will be viewed as an example of how international cooperation is contagious.     

Observer-based tracking control of abnormal oscillations in demyelination symptom

Fast axonal conduction of action potentials in mammals relies on myelin insulation. Demyelination can cause slowed, blocked, desynchronized, or paradoxically excessive spiking that underlies the symptoms observed in demyelination diseases. Feedback control via functional electrical stimulation (FES) seems to be a promising treatment modality in such diseases. However, there are challenges to implementing such method for neurons: high nonlinearity, biological tissue constrains and unobservable ion channel states. To address this problem, we propose an estimating and tracking control strategy for systems based on Kalman filter, in order to enhance the action potential propagation reliability of demyelinated neuron via FES. Unscented Kalman filter (UKF) is employed to estimate the unobservable states and parameters in the demyelination neuron model from membrane potential dynamics. Our method could promote the design of new closed-loop electrical stimulation systems for patients suffering from different nerve system dysfunctions.     

A morphometric analysis of Scottish Athyrium distentifolium: a contribution to the BAP

Summary

A morphologically distinct variety of Athyrium distentifolium called A. distentifolium var. flexile has been found only in Scotland. Research was undertaken for aUK Biodiversity Action Plan. To confirm that this taxon has a definitely recognisable morphology, a morphometric analysis was used on the range of characters used to define this variety. It showed that it can be clearly differentiated.     

Maintenance and recovery of rare clonal plants: the Case of the twinflower (Linnaea borealis L.)

Summary

Populations of rare clonally spreading species are increasingly being shown to be composed of one or a few genotypes. Clones have potentially unlimited life but two factors, genetic erosion due to random events and increasing accumulation of genetic load in older genotypes, combine to expose them to sexual failure and loss of fertility. Non-breeding clonal populations are at risk of extinction because they lack the ability to adapt or escape from changing environments.

Twinflower (Linnaea borealis L.) has been lost from nearly 50 % of its pre-1970 sites. It is a clonal self-incompatible plant and sexual failure has been reported from Canada, Britain and Scandinavia. Sexual failure is due to high levels of within-clone pollination by flies. Seed set occurs naturally in Scottish populations which have some genetic diversity. A non-breeding population in Scotland has been restored to viability by experimental cross-pollination with pollen from a distant source. Conservation action for this species should therefore be directed to the prevention of loss of habitat and restoration of population viability by translocation of compatible mates.

Translocating plants into extant, but non-breeding, populations are still a matter of debate and are frequently opposed. However, experimental translocations must now be performed to establish whether intervention can secure the long-term survival of rare clonal plants without the constant need for re-introduction.     

Microdosimetry: Principles and applications

Aim

to present the most important aspects of Microdosimetry, a research field in radiation biophysics.

Background

microdosimetry is the branch of radiation biophysics that systematically studies the spatial, temporal and spectral aspects of the stochastic nature of the energy deposition processes in microscopic structures.

Materials and Methods

we briefly review its history, the people, the formalism and the theories and devices that allowed researchers to begin to understand the true nature of radiation action on living matter.

Results and Conclusions

we outline some of its applications, especially to Boron Neutron Capture Therapy, attempting to explain the biological effectiveness of the boron thermal neutron capture reaction.     

丙酮酸乙酯的合成及药理作用研究

丙酮酸乙酯是一种重要的医药中间体,在医药、农药、食品、化妆品等领域有广泛的用途。其合成方法和药理作用一直是研究的热点。近年来愈来愈多的文章报道了丙酮酸乙酯的各种合成及工艺方法,一些新的生理活性也不断见诸于文献。本文从丙酮酸乙酯的合成方法及药理作用两方面进行综述,主要介绍了乳酸乙酯氧化法、有机金属试剂法和酯化法三种合成丙酮酸乙酯的方法,并从工艺角度对各种方法的优缺点进行了分析;阐述了其抗氧化、抗炎、抗肿瘤作用的研究进展,并对丙酮酸乙酯的药物应用前景进行了展望,期望能够为丙酮酸乙酯的进一步成药性研究提供思路和启发。     

二维心室建模和Brugada综合症仿真

本文以Tusscher提出的人体心室单细胞计算模型为基础,用计算机建模仿真的方法,构建一个心室壁组织的二维网格模型。通过修改细胞的离子通道参数,仿真了正常生理条件下和Brugada症状下三类心室细胞的动作电位和心电图波形。结果显示:Brugada症状下的心电图波形有明显的J波出现,ST-段抬高甚至T波倒置。这与临床医学上的报道基本符合,本研究为用计算机仿真建模研究Brugada综合症打下了基础。     

Choline Modulates Cardiac Membrane Repolarization by Activating an M3 Muscarinic Receptor and its Coupled K+ Channel

Choline is a necessary substrate of the lipid membrane and for acetylcholine synthesis. Accumulating evidence indicates that besides being a structural component, choline is also a functional modulator of the membrane. It has been shown to be a muscarinic acetylcholine receptor (mAChR) agonist and can induce a novel K⁺ current in cardiac cells. However, the potential role of choline in modulating cardiac functions remained unstudied despite that mAChRs are known to be important in regulating heart functions. With microelectrode techniques, we found that choline produced concentration-dependent (0.1∼10 mm) decreases in sinus rhythm and action potential duration in isolated guinea pig atria. The effects were reversed by 2 nm 4DAMP (an M₃-selective antagonist). Whole-cell patch-clamp recordings in dispersed myocytes from guinea pig and canine atria revealed that choline is able to induce a K⁺ current with delayed rectifying properties. The choline-induced current was suppressed by low concentrations of 4DAMP (2∼10 nm). Antagonists toward other subtypes (M₁, M₂ or M₄) all failed to alter the current. The affinity of choline (K _d ) at mAChRs derived from displacement binding of [³H]-NMS in the homogenates from dog atria was 0.9 mm, consistent with the concentration needed for the current induction and for the HR and APD modulation. Our data indicate that choline modulates the cellular electrical properties of the hearts, likely by activating a K⁺ current via stimulation of M₃ receptors. Received: 1 December 1998/Revised: 12 February 1999     

Intracellular calcium and the relationship to contractility in an avian model of heart failure

Global contractile heart failure was induced in turkey poults by furazolidone feeding (700 ppm). Abnormal calcium regulation appears to be a key factor in the pathophysiology of heart failure, but the cellular mechanisms contributing to changes in calcium fluxes have not been clearly defined. Isolated ventricular myocytes from non-failing and failing hearts were therefore used to determine whether the whole heart and ventricular muscle contractile dysfunctions were realized at the single cell level. Whole cell current- and voltage-clamp techniques were used to evaluate action potential configurations and L-type calcium currents, respectively. Intracellular calcium transients were evaluated in isolated myocytes with fura-2 and in isolated left ventricular muscles using aequorin. Action potential durations were prolonged in failing myocytes, which correspond to slowed cytosolic calcium clearing. Calcium current-voltage relationships were normal in failing myocytes; preliminary evidence suggests that depressed transient outward potassium currents contribute to prolonged action potential durations. The number of calcium channels (as measured by radioligand binding) were also similar in non-failing and failing hearts. Isolated ventricular muscles from failing hearts had enhanced inotropic responses, in a dose-dependent fashion, to a calcium channel agonist (Bay K 8644). These data suggest that changes in intracellular calcium mobilization kinetics and longer calcium-myofilament interaction may be able to compensate for contractile failure. We conclude that the relationship between calcium current density and sarcoplasmic reticulum calcium release is a dynamic process that may be altered in the setting of heart failure at higher contraction rates. Accepted: 1 March 2000