Book Review

Acute cholesterol depletion is generally associated with decreased or abolished T cell signalling but it can also cause T cell activation. This anomaly has been addressed in Jurkat T cells using progressive cholesterol depletion with methyl-beta-cyclodextrin (MBCD). At depletion levels higher than 50% there is substantial cell death, which explains reports of signalling inhibition. At 10–20% depletion levels, tyrosine phosphorylation is increased, ERK is activated and there is a small increase in cytoplasmic Ca2+. Peripheral actin polymerisation is also triggered by limited cholesterol depletion. Strikingly, the lipid raft marker GM1 aggregates upon cholesterol depletion and these aggregated domains concentrate the signalling proteins Lck and LAT, whereas the opposite is true for the non lipid raft marker the transferrin receptor. Using PP2, an inhibitor of Src family kinase activation, it is demonstrated that the lipid raft aggregation occurs independently of and thus upstream of the signalling response. Upon cholesterol depletion there is an increase in overall plasma membrane order, indicative of more ordered domains forming at the expense of disordered domains. That cholesterol depletion and not unspecific effects of MBCD was behind the reported results was confirmed by performing all experiments with MBCD–cholesterol, when no net cholesterol extraction took place. We conclude that non-lethal cholesterol depletion causes the aggregation of lipid rafts which then induces T cell signalling

Relative Importance Sampling For Off-Policy Actor-Critic in Deep Reinforcement Learning

Off-policy learning is more unstable compared to on-policy learning in reinforcement learning (RL). One reason for the instability of off-policy learning is a discrepancy between the target ($\pi$) and behavior (b) policy distributions. The discrepancy between $\pi$ and b distributions can be alleviated by employing a smooth variant of the importance sampling (IS), such as the relative importance sampling (RIS). RIS has parameter $\beta\in[0, 1]$ which controls smoothness. To cope with instability, we present the first relative importance sampling-off-policy actor-critic (RIS-Off-PAC) model-free algorithms in RL. In our method, the network yields a target policy (the actor), a value function (the critic) assessing the current policy ($\pi$) using samples drawn from behavior policy. We use action value generated from the behavior policy in reward function to train our algorithm rather than from the target policy. We also use deep neural networks to train both actor and critic. We evaluated our algorithm on a number of Open AI Gym benchmark problems and demonstrate better or comparable performance to several state-of-the-art RL baselines

Klimawandelinduzierte Verletzlichkeitsanalyse von Unternehmen und Branchen für 2030: Konzeptioneller Bezugsrahmen und empirische Befunde

Die deutschen Unternehmen sind bereits heute von Klimafolgen und Extremwetterereignissen betroffen. Unternehmen werden sich aber in Zukunft noch stärker auf die Auswirkungen des Klimawandels einstellen müssen. Sie erwarten, dass direkte und/oder indirekte Betroffenheit durch das Klimawandelphänomen bis 2030 zunehmen werden, und zwar in negativer Weise. Das geht aus einer bundesweiten Unternehmensbefragung durch das Institut der deutschen Wirtschaft Köln (IW) hervor, die Mahammad Mahammadzadeh, IW, in diesem Beitrag vorstellt. Ob und inwieweit die negativen Betroffenheit auch zu einer Verletzlichkeit der Betroffenen führt bzw. führen könnte, hängt insbesondere von deren Anpassungskapazität der finanziellen, personellen, technologischen, infrastrukturellen, institutionellen und wissensbasierten Ressourcen und Kompetenzen sowie den bereits implementierten oder geplanten Anpassungsmaßnahmen zur Reduzierung der negativen Betroffenheit durch die Klimafolgen ab. Den Ergebnissen der Umfrage zufolge besteht derzeit bei jedem zweiten deutschen Unternehmen ein Bedarf an Anpassungsmaßnahmen, die sowohl die betriebliche Infrastruktur und Versicherung gegen die Klimafolgen und Extremwetterereignisse als auch Frühwarn- und Informationssysteme sowie Klimaberatungen und Klimarisikomanagement einschließen

Betroffenheit von Unternehmen und Kommunen durch den Klimawandel und Handlungsoptionen

Die Klimapolitik kann nicht mehr nur aus Klimaschutzmaßnahmen bestehen, sondern muss auch heute schon Anpassungsmaßnahmen an die Folgen des Klimawandels ergreifen. Diese Maßnahmen können einander unterstützen, aber auch gegenläufig wirken. In einer systematischen Aufstellung werden die Betroffenheit der jeweiligen Akteure erfasst und Reaktionsmöglichkeiten aufgezeigt

A study on the relationship between factors of physical environment comfort and employees job performance at Majlis Bandaraya Kuala Terengganu / Nurul Syakira Mahammad

The purpose of this study is to measure the relationship between physical environment comfort and employees' job performance at Majlis Bandaraya Kuala Terengganu (MBKT) located in Kuala Terengganu. This study also needs to identify which physical environment comfort factors that most influence the employees' job performance. Besides that, this study uses to identify the current problem faced by the employees from physical environment comfort toward their job performance. This study was conducted among the employees in three departments in the organization and the questionnaires have been distributed to all departments in the departments. The total population of this study was about 40 employees and 36 of them were took part as a respondents in answering the questionnaires. Through the findings, ergonomic office equipment factor is the most significant factor of physical environment comfort that affect employees' job performance while the least significant factor was noise. Several recommendations were suggested in order to make some improvement to the employees' job performance at Majlis Bandaraya Kuala Terengganu

Wahrnehmung des Klimawandels in deutschen Großunternehmen: Erkenntnisse aus dem Carbon Disclosure Project

Um den Klimawandel zu begrenzen, sind Anstrengungen auf globaler Ebene notwendig. Um sich an die Folgen des Klimawandels anzupassen, sind jedoch auch individuelle Strategien zur Risikovorsorge effektiv. Allerdings stehen frühzeitigen Anpassungsaktivitäten entgegen, dass die möglichen Klimafolgen häufig nicht wahrgenommen werden oder außerhalb der unternehmerischen Planungshorizonte liegen. Für die größten deutschen Unternehmen sind Risiken und Chancen infolge von Klimaveränderungen zunehmend präsent. In den kleinen und mittelständischen Unternehmen ist dies gegenwärtig weniger der Fall

The analysis of the main indicators evolution of social and economic development in the Arab republic of Syria, period 1960-2014

The paper's aim is a retrospective analysis of the evolution of the main indicators of social and economic development from Syria by highlighting the degree of development of the country before the policy crisis in 2011. An attempt was also the surprise of external and internal influences in the country: a comparison with neighboring Arab countries of Syria, managing the formation of an overview image of economic and social development of the country, and the effects of the civil war start in 2011 resulting from the analysis of statistical data and official reports. The key indicators analyzed have been the Gross Domestic Product and the Human Development Index, the evolution being completed by the analysis of the main indicators that characterizes the evolution of agriculture in the period analyzed. The result of the research shows a country with a developed evolution potential, the development indicators up to 2011 being favorable for the country, but the conflict from 2011 affecting all economic and social sectors, the damage and the possibilities of economic recovery is still very hard to estimate

Response of the topological surface state to surface disorder in TlBiSe2_2

Through a combination of experimental techniques we show that the topmost layer of the topo- logical insulator TlBiSe$_2$ as prepared by cleavage is formed by irregularly shaped Tl islands at cryogenic temperatures and by mobile Tl atoms at room temperature. No trivial surface states are observed in photoemission at low temperatures, which suggests that these islands can not be re- garded as a clear surface termination. The topological surface state is, however, clearly resolved in photoemission experiments. This is interpreted as a direct evidence of its topological self-protection and shows the robust nature of the Dirac cone like surface state. Our results can also help explain the apparent mass acquisition in S-doped TlBiSe$_2$.Comment: 16 pages, 5 figure

Establishing a Performance Testing Approach for E-Learning Applications

Most of the E-Learning applications perform poorly in motivating employees to learn. To solve this problem, we need to examine what workplace e-learning requires and how workplace e-learning systems should be developed in line with those requirements. We investigated the problem by identifying the fundamental elements of the workplace learning environment including the learner, organization, learning content and social context, and their relationships. We found that workplace e-learning should align individual and organizational learning needs, connect learning and work performance, and support social interaction among individuals. To achieve this, a performance testing approach is proposed. Key performance indicators are utilized to clarify organizational goals, make sense of work context and requests on work performance, and accordingly help employees set up rational learning objectives and enhance their learning process. Using this approach, prototype system has been developed and a set of experiments have been conducted to demonstrate the effectiveness of the approach. This paper also presents the use of software verification, validation and testing technique, traditionally used in the software development, in the design and implementation of E-Learning products. We examine the ways one can apply testing techniques in E-Learning life cycle. This includes the strategy adoption for the selection of testing technique along with tool acquisition and measurement. The objective is to develop a collaborative approach involving software testing and educational methodology