994 resultados para Shape context
Resumo:
How are cell morphogenesis and cell cycle coordinated? The fission yeast is a rod-shaped unicellular organism widely used to study how a cell self-organizes in space and time. Here, we discuss recent advances in understanding how the cell acquires and maintains its regular rod shape and uses it to control cell division. The cellular body plan is established by microtubules, which mark antipodal growth zones and medial division. In turn, cellular dimensions are defined by the small GTPase Cdc42 and downstream regulators of vesicle trafficking. Yeast cells then repetitively use their simple rod shape to orchestrate the position and timing of cell division.
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The hydrogen isotope ratio (HIR) of body water and, therefore, of all endogenously synthesized compounds in humans, is mainly affected by the HIR of ingested drinking water. As a consequence, the entire organism and all of its synthesized substrates will reflect alterations in the isotope ratio of drinking water, which depends on the duration of exposure. To investigate the effect of this change on endogenous urinary steroids relevant to doping-control analysis the hydrogen isotope composition of potable water was suddenly enriched from -50 to 200 0/00 and maintained at this level for two weeks for two individuals. The steroids under investigation were 5β-pregnane-3α,20α-diol, 5α-androst-16-en-3α-ol, 3α-hydroxy-5α-androstan-17-one (ANDRO), 3α-hydroxy-5β-androstan-17-one (ETIO), 5α-androstane-3α,17β-diol, and 5β-androstane-3α,17β-diol (excreted as glucuronides) and ETIO, ANDRO and 3β-hydroxyandrost-5-en-17-one (excreted as sulfates). The HIR of body water was estimated by determination of the HIR of total native urine, to trace the induced changes. The hydrogen in steroids is partly derived from the total amount of body water and cholesterol-enrichment could be calculated by use of these data. Although the sum of changes in the isotopic composition of body water was 150 0/00, shifts of approximately 30 0/00 were observed for urinary steroids. Parallel enrichment in their HIR was observed for most of the steroids, and none of the differences between the HIR of individual steroids was elevated beyond recently established thresholds. This finding is important to sports drug testing because it supports the intended use of this novel and complementary methodology even in cases where athletes have drunk water of different HIR, a plausible and, presumably, inevitable scenario while traveling.
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DNA in bacterial chromosomes and bacterial plasmids is supercoiled. DNA supercoiling is essential for DNA replication and gene regulation. However, the density of supercoiling in vivo is circa twice smaller than in deproteinized DNA molecules isolated from bacteria. What are then the specific advantages of reduced supercoiling density that is maintained in vivo? Using Brownian dynamics simulations and atomic force microscopy we show here that thanks to physiological DNA-DNA crowding DNA molecules with reduced supercoiling density are still sufficiently supercoiled to stimulate interaction between cis-regulatory elements. On the other hand, weak supercoiling permits DNA molecules to modulate their overall shape in response to physiological changes in DNA crowding. This plasticity of DNA shapes may have regulatory role and be important for the postreplicative spontaneous segregation of bacterial chromosomes.
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Cooperation and Working Together (CAWT), the cross border health and social care partnership has been working with the Departments of Health to progress a three year cross border obesity prevention and management project aimed at families. They have been successful in securing funding from the EU INTERREG IVA programme. A planning workshop focussing on this will be held on Friday 26 June 2009.
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Songs were the means used by the Romanian Communist Party to ‘educate’ Romanians. Through them, Romanians were told what they had to appreciate, how grateful they were supposed to be to the regime, how great President Ceausescu was and how they had to work harder and harder so that they could be even better Communists. This paper comprises the translation of three songs composed, performed and broadcast in Communist Romania and their analysis from the point of view of communication. In translating the song, I have chosen to translate closest to the original possible meaning and meanwhile to respect to the best of my ability Low’s ‘pentathlon principle’: singability, rhyme, rhythm, naturalness and fidelity to the sense of the source text
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From an anthropological perspective, formal post-secondary schooling is not an abstractentity with an intrinsic value that everyone finds desirable, but rather one alternative among many that young people evaluate from their different positions in the social field. The problem discussed in this paper is the diverging life trajectories that young men and women in a concrete rural context, at the end of the 20th century, shape for themselves at the ages of 14-16, a moment of decision created by national legislation regarding mandatory education (LGE, 1970, General Education Law, and LOGSE, 1990, General Organic Law of the Education System). Despite a strong cultural norm of equal inheritance divided among all children, male and female, and despite the equal educational opportunities provided by the Spanish State, different meanings of possession and use-rights over land and the resulting culturally accepted gendered division of work converge to orient men and women differently towards post-secondary schooling. Observation of the age, gender, and civil status structure of the population led to the preliminary query: Why do men and women, in this town, behave differently with respect to migration and marriage? The main hypothesis was that women’s longer school trajectories and resulting migration and men’s anchoring in the town and their higher rates of celibacy were not drastic changes in values, in the positional-relational sense of Bourdieu (1988, 2002), but the current outcome of previously existing dissimilar relations to property that produce dissimilar mobility. Through their schooling and work choices, young men and women, at very early ages, locate themselves in, or decide to belong to, different contexts that later reveal very different possibilities of finding marriage partners. This paper is based on an ethnographic study of a small rural town (302 inhabitants in 1950; 193 in 2000) near Leon. Although this paper deals with the situation in the final decades of the 20th century, we must also consider the first half of the century, where some elements that shape this situation have their roots. Fieldwork was carried out between 1988 and 2001, in periods of differing length and intensity. The social subjects discussed here are the domestic unit and its component members. They were studied in conjunction, analyzing the life-trajectory decisions of specific persons in the framework of the domestic unit and the relations among people and property which comprise it. The tried-and-true methods of ethnographic research –participant observation, interviews, and life-histories, etc.- were employed. Archival research was also important for producing demographic data. Demographic analysis, the analysis of the composition and transformation of domestic units, and the creation of life trajectories were among the principal techniques used. The theoretical analysis was oriented by Bourdieu’s (2002) framework of the social field, habitus, and difference.
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La importància de la formació permanent és indiscutible en qualsevol context laboral i molt especialment en les actuals circumstàncies de crisi econòmica mundial. Però en l'actual espai europeu d'educació superior (EEES), les tendències i els plans de formació contínua adquireixen una dimensió global, que supera o, millor dit, hauria de superar els plantejaments reduccionistes. Per això, la construcció i el desenvolupament de l'espai europeu de formació permanent, EEFP (Comissió de les Comunitats Europees, 2001a), ha d'entendre's com un procés que està immers en un teixit més ampli. Es tracta d'una acció en xarxa on és necessària la implicació de molts agents actius professionals i on la convergència, el reconeixement i la cohesió han de ser els seus màxims elements qualitatius
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Review of the book : "What shape is a snowflake?", by I.S. Weidenfeld & Nicholson, London, UK
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In addition to the monographs which were published last year by the working group "Drug Monitoring" of the Swiss Society of Clinical Chemistry (SSCC) [1], new monographs have been written. The aim of these monographs is to give an overview of the most important information necessary for ordering a drug analysis or interpreting the results. Therefore, the targeted readers comprise laboratory health professionals and all receivers of laboratory reports. There is information provided on the indication for therapeutic drug monitoring, protein binding, metabolic pathways and enzymes involved, elimination half-life and elimination routes, and on therapeutic or toxic concentrations. Preanalytical considerations are of particular importance for therapeutic drug monitoring. Therefore, information is provided regarding a reasonable timing for the determination of drug concentrations as well as steady-state concentrations after changing the dose. Furthermore, the stability of the drug and its metabolite(s) after blood sampling is described. For readers with a specific interest in drug analysis, references to important publications are given. The number of monographs will be continuously enlarged. The updated files are presented on the homepage of the SSCC (www.sscc.ch).
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Impaired visual search is a hallmark of spatial neglect. When searching for an unique feature (e.g., color) neglect patients often show only slight visual field asymmetries. In contrast, when the target is defined by a combination of features (e.g., color and form) they exhibit a severe deficit of contralesional search. This finding suggests a selective impairment of the serial deployment of spatial attention. Here, we examined this deficit with a preview paradigm. Neglect patients searched for a target defined by the conjunction of shape and color, presented together with varying numbers of distracters. The presentation time was varied such that on some trials participants previewed the target together with same-shape/different-color distracters, for 300 or 600 ms prior to the appearance of additional different-shape/same-color distracters. On the remaining trials the target and all distracters were shown simultaneously. Healthy participants exhibited a serial search strategy only when all items were presented simultaneously, whereas in both preview conditions a pop-out effect was observed. Neglect patients showed a similar pattern when the target was presented in the right hemifield. In contrast, when searching for a target in the left hemifield they showed serial search in the no-preview condition, as well as with a preview of 300 ms, and partly even at 600 ms. A control experiment suggested that the failure to fully benefit from item preview was probably independent of accurate perception of time. Our results, when viewed in the context of existing literature, lead us to conclude that the visual search deficit in neglect reflects two additive factors: a biased representation of attentional priority in favor of ipsilesional information and exaggerated capture of attention by ipsilesional abrupt onsets.
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While mobile technologies can provide great personalized services for mobile users, they also threaten their privacy. Such personalization-privacy paradox are particularly salient for context aware technology based mobile applications where user's behaviors, movement and habits can be associated with a consumer's personal identity. In this thesis, I studied the privacy issues in the mobile context, particularly focus on an adaptive privacy management system design for context-aware mobile devices, and explore the role of personalization and control over user's personal data. This allowed me to make multiple contributions, both theoretical and practical. In the theoretical world, I propose and prototype an adaptive Single-Sign On solution that use user's context information to protect user's private information for smartphone. To validate this solution, I first proved that user's context is a unique user identifier and context awareness technology can increase user's perceived ease of use of the system and service provider's authentication security. I then followed a design science research paradigm and implemented this solution into a mobile application called "Privacy Manager". I evaluated the utility by several focus group interviews, and overall the proposed solution fulfilled the expected function and users expressed their intentions to use this application. To better understand the personalization-privacy paradox, I built on the theoretical foundations of privacy calculus and technology acceptance model to conceptualize the theory of users' mobile privacy management. I also examined the role of personalization and control ability on my model and how these two elements interact with privacy calculus and mobile technology model. In the practical realm, this thesis contributes to the understanding of the tradeoff between the benefit of personalized services and user's privacy concerns it may cause. By pointing out new opportunities to rethink how user's context information can protect private data, it also suggests new elements for privacy related business models.
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La recerca vol determinar, principalment, si continua donant-se i sent vàlida la transmissió de la cultura oral de l'Àfrica occidental fora del seu context originari, en el cas concret del col·lectiu senegalès a l'àrea de Barcelona.