933 resultados para British acting
Resumo:
Families of clonally expressed major histocompatibility complex (MHC) class I-specific receptors provide specificity to and regulate the function of natural killer (NK) cells. One of these receptors, mouse Ly49A, is expressed by 20% of NK cells and inhibits the killing of H-2D(d) but not D(b)-expressing target cells. Here, we show that the trans-acting factor TCF-1 binds to two sites in the Ly49A promoter and regulates its activity. Moreover, we find that TCF-1 determines the size of the Ly49A NK cell subset in vivo in a dosage-dependent manner. We propose that clonal Ly49A acquisition during NK cell development is regulated by TCF-1.
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Azole resistance in Candida albicans can be mediated by the upregulation of the ATP binding cassette transporter genes CDR1 and CDR2. Both genes are regulated by a cis-acting element called the drug-responsive element (DRE), with the consensus sequence 5'-CGGAWATCGGATATTTTTTT-3', and the transcription factor Tac1p. In order to analyze in detail the DRE sequence necessary for the regulation of CDR1 and CDR2 and properties of TAC1 alleles, a one-hybrid system was designed. This system is based on a P((CDR2))-HIS3 reporter system in which complementation of histidine auxotrophy can be monitored by activation of the reporter system by CDR2-inducing drugs such as estradiol. Our results show that most of the modifications within the DRE, but especially at the level of CGG triplets, strongly reduce CDR2 expression. The CDR2 DRE was replaced by putative DREs deduced from promoters of coregulated genes (CDR1, RTA3, and IFU5). Surprisingly, even if Tac1p was able to bind these putative DREs, as shown by chromatin immunoprecipitation, those from RTA3 and IFU5 did not functionally replace the CDR2 DRE. The one-hybrid system was also used for the identification of gain-of-function (GOF) mutations either in TAC1 alleles from clinical C. albicans isolates or inserted in TAC1 wild-type alleles by random mutagenesis. In all, 17 different GOF mutations were identified at 13 distinct positions. Five of them (G980E, N972D, A736V, T225A, and N977D) have already been described in clinical isolates, and four others (G980W, A736T, N972S, and N972I) occurred at already-described positions, thus suggesting that GOF mutations can occur in a limited number of positions in Tac1p. In conclusion, the one-hybrid system developed here is rapid and powerful and can be used for characterization of cis- and trans-acting elements in C. albicans.
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This paper presents the use of our multimodal mixed reality telecommunication system to support remote acting rehearsal. The rehearsals involved two actors, located in London and Barcelona, and a director in another location in London. This triadic audiovisual telecommunication was performed in a spatial and multimodal collaborative mixed reality environment based on the 'destination-visitor' paradigm, which we define and put into use. We detail our heterogeneous system architecture, which spans the three distributed and technologically asymmetric sites, and features a range of capture, display, and transmission technologies. The actors' and director's experience of rehearsing a scene via the system are then discussed, exploring successes and failures of this heterogeneous form of telecollaboration. Overall, the common spatial frame of reference presented by the system to all parties was highly conducive to theatrical acting and directing, allowing blocking, gross gesture, and unambiguous instruction to be issued. The relative inexpressivity of the actors' embodiments was identified as the central limitation of the telecommunication, meaning that moments relying on performing and reacting to consequential facial expression and subtle gesture were less successful.
Resumo:
This paper presents the use of our multimodal mixed reality telecommunication system to support remote acting rehearsal. The rehearsals involved two actors, located in London and Barcelona, and a director in another location in London. This triadic audiovisual telecommunication was performed in a spatial and multimodal collaborative mixed reality environment based on the 'destination-visitor' paradigm, which we define and put into use. We detail our heterogeneous system architecture, which spans the three distributed and technologically asymmetric sites, and features a range of capture, display, and transmission technologies. The actors' and director's experience of rehearsing a scene via the system are then discussed, exploring successes and failures of this heterogeneous form of telecollaboration. Overall, the common spatial frame of reference presented by the system to all parties was highly conducive to theatrical acting and directing, allowing blocking, gross gesture, and unambiguous instruction to be issued. The relative inexpressivity of the actors' embodiments was identified as the central limitation of the telecommunication, meaning that moments relying on performing and reacting to consequential facial expression and subtle gesture were less successful.
Resumo:
We have previously shown that transcription from the vaccinia virus 7.5K early promoter is reactivated late in infection (J. Garcés, K. Masternak, B. Kunz, and R. Wittek, J. Virol. 67:5394-5401, 1993). To identify the sequence elements mediating reactivation, we constructed recombinant viruses harboring deletions, substitutions, or insertions in the 7.5K promoter or its flanking regions. The analysis of these viruses showed that sequences both upstream as well as downstream of the transcription initiation site contribute to reactivation of the 7.5K promoter. We tested whether reactivation could be explained by a high affinity of vaccinia virus early transcription factor to reactivated promoters. Bandshift experiments using purified protein showed that promoters which bind the factor with high affinity in general also have high early transcriptional activity. However, no correlation was found between affinity of the factor and reactivation. Interestingly, overexpression of recombinant early transcription factor in vaccinia virus-infected cells resulted in a shutdown of late transcription and in reactivation of promoters, which are normally not reactivated.
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We present a complete Raman spectroscopic study in two structurally well-defined diradical species of different lengths incorporating oligo p-phenylene vinylene bridges between two polychlorinated triphenylmethyl radical units, a disposition that allows sizeable conjugation between the two radicals through and with the bridge. The spectroscopic data are interpreted and supported by quantum chemical calculations. We focus the attention on the Raman frequency changes, interpretable in terms of: (i) bridge length (conjugation length); (ii) bridge conformational structure; and (iii) electronic coupling between the terminal radical units with the bridge and through the bridge, which could delineate through-bond spin polarization, or spin delocalization. These items are addressed by using the"oligomer approach" in conjunction with pressure and temperature dependent Raman spectroscopic data. In summary, we have attempted to translate the well-known strategy to study the electron (charge) structure of π−conjugated molecules by Raman spectroscopy to the case of electron (spin) interactions via the spin delocalization mechanism.
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Purpose: To describe (1) the clinical profiles and the patterns of use of long-acting injectable (LAI) antipsychotics in patients with schizophrenia at risk of nonadherence with oral antipsychotics, and in those who started treatment with LAI antipsychotics, (2) health care resource utilization and associated costs. Patients and methods: A total of 597 outpatients with schizophrenia at risk of nonadherence, according to the psychiatrist's clinical judgment, were recruited at 59 centers in a noninterventional prospective observational study of 1-year follow-up when their treatment was modified. In a post hoc analysis, the profiles of patients starting LAI or continuing with oral antipsychotics were described, and descriptive analyses of treatments, health resource utilization, and direct costs were performed in those who started an LAI antipsychotic. Results: Therapy modifications involved the antipsychotic medications in 84.8% of patients, mostly because of insufficient efficacy of prior regimen. Ninety-two (15.4%) patients started an LAI antipsychotic at recruitment. Of these, only 13 (14.1%) were prescribed with first-generation antipsychotics. During 1 year, 16.3% of patients who started and 14.9% of patients who did not start an LAI antipsychotic at recruitment relapsed, contrasting with the 20.9% who had been hospitalized only within the prior 6 months. After 1 year, 74.3% of patients who started an LAI antipsychotic continued concomitant treatment with oral antipsychotics. The mean (median) total direct health care cost per patient per month during the study year among the patients starting any LAI antipsychotic at baseline was 1,407 ( 897.7). Medication costs (including oral and LAI antipsychotics and concomitant medication) represented almost 44%, whereas nonmedication costs accounted for more than 55% of the mean total direct health care costs. Conclusion: LAI antipsychotics were infrequently prescribed in spite of a psychiatrist-perceived risk of nonadherence to oral antipsychotics. Mean medication costs were lower than nonmedication costs.
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Vitellogenin genes are expressed under strict estrogen control in the liver of female oviparous vertebrates. Gene transfer experiments using estrogen-responsive cells have shown that the 13 bp perfect palindromic element GGTCACTGTGACC found upstream of the Xenopus laevis vitellogenin gene A2 promoter mediates hormonal stimulation and thus, was called the estrogen-responsive element (ERE). In the Xenopus vitellogenin genes B1 and B2 there are two closely adjacent EREs with one or more base substitutions when compared to the consensus ERE GGTCANNNTGACC. On their own, these degenerated elements have only a low or no regulatory capacity at all but act together synergistically to form an estrogen-responsive unit (ERU) with the same strength as the perfect palindromic 13 bp element. Analysis of estrogen receptor binding to the gene B1 ERU revealed a cooperative interaction of receptor dimers to the two adjacent imperfect EREs which most likely explains the synergistic stimulation observed in vivo. Furthermore, a promoter activator element located between positions --113 and --42 of the gene B1 and functional in the human MCF-7 and the Xenopus B3.2 cells has been identified and shown to be involved in the high level of induced transcription activity when the ERE is placed at a distance from the promoter. Finally, a hormone-controlled in vitro transcription system derived from Xenopus liver nuclear extracts was exploited to characterize two additional novel cis-acting elements within the vitellogenin gene B1 promoter. One of them, a negative regulatory element (NRE), is responsible for repression of promoter activity in the absence of hormone. The second is related to the NF-I binding site and is required, together with the ERE, to mediate hormonal induction. Moreover, we detected three trans-acting activities in Xenopus liver nuclear extracts that interact with these regions and demonstrated that they participate in the regulation of the expression of the vitellogenin promoter in vitro.
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This paper asks a simple question: if humans and their actions co-evolve with hydrological systems (Sivapalan et al., 2012), what is the role of hydrological scientists, who are also humans, within this system? To put it more directly, as traditionally there is a supposed separation of scientists and society, can we maintain this separation as socio-hydrologists studying a socio-hydrological world? This paper argues that we cannot, using four linked sections. The first section draws directly upon the concern of science-technology studies to make a case to the (socio-hydrological) community that we need to be sensitive to constructivist accounts of science in general and socio-hydrology in particular. I review three positions taken by such accounts and apply them to hydrological science, supported with specific examples: (a) the ways in which scientific activities frame socio-hydrological research, such that at least some of the knowledge that we obtain is constructed by precisely what we do; (b) the need to attend to how socio-hydrological knowledge is used in decision-making, as evidence suggests that hydrological knowledge does not flow simply from science into policy; and (c) the observation that those who do not normally label themselves as socio-hydrologists may actually have a profound knowledge of socio-hydrology. The second section provides an empirical basis for considering these three issues by detailing the history of the practice of roughness parameterisation, using parameters like Manning's n, in hydrological and hydraulic models for flood inundation mapping. This history sustains the third section that is a more general consideration of one type of socio-hydrological practice: predictive modelling. I show that as part of a socio-hydrological analysis, hydrological prediction needs to be thought through much more carefully: not only because hydrological prediction exists to help inform decisions that are made about water management; but also because those predictions contain assumptions, the predictions are only correct in so far as those assumptions hold, and for those assumptions to hold, the socio-hydrological system (i.e. the world) has to be shaped so as to include them. Here, I add to the ``normal'' view that ideally our models should represent the world around us, to argue that for our models (and hence our predictions) to be valid, we have to make the world look like our models. Decisions over how the world is modelled may transform the world as much as they represent the world. Thus, socio-hydrological modelling has to become a socially accountable process such that the world is transformed, through the implications of modelling, in a fair and just manner. This leads into the final section of the paper where I consider how socio-hydrological research may be made more socially accountable, in a way that is both sensitive to the constructivist critique (Sect. 1), but which retains the contribution that hydrologists might make to socio-hydrological studies. This includes (1) working with conflict and controversy in hydrological science, rather than trying to eliminate them; (2) using hydrological events to avoid becoming locked into our own frames of explanation and prediction; (3) being empirical and experimental but in a socio-hydrological sense; and (4) co-producing socio-hydrological predictions. I will show how this might be done through a project that specifically developed predictive models for making interventions in river catchments to increase high river flow attenuation. Therein, I found myself becoming detached from my normal disciplinary networks and attached to the co-production of a predictive hydrological model with communities normally excluded from the practice of hydrological science.
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1. This account presents information on all aspects of the biology of Ambrosia artemisiifolia L. (Common ragweed) that are relevant to understanding its ecology. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation, impacts and management. 2. Ambrosia artemisiifolia is a monoecious, wind-pollinated, annual herb native to North America whose height varies from 10 cm to 2.5 m according to environmental conditions. It has erect, branched stems and pinnately lobed leaves. Spike-like racemes of male capitula composed of staminate (male) florets terminate the stems, while cyme-like clusters of pistillate (female) florets are arranged in groups the axils of main and lateral stem leaves. 3. Seeds require prolonged chilling to break dormancy. Following seedling emergence in spring, the rate of vegetative growth depends on temperature, but development occurs over a wide thermal range. In temperate European climates, male and female flowers are produced from summer to early autumn (July to October). 4. Ambrosia artemisiifolia is sensitive to freezing. Late spring frosts kill seedlings and the first autumn frosts terminate the growing season. It has a preference for dry soils of intermediate to rich nutrient level. 5. Ambrosia artemisiifolia was introduced into Europe with seed imports from North America in the 19th century. Since World War II, it has become widespread in temperate regions of Europe and is now abundant in open, disturbed habitats as a ruderal and agricultural weed. 6. Recently, the N. American ragweed leaf beetle (Ophraella communa) has been detected in southern Switzerland and northern Italy. This species appears to have the capacity to substantially reduce growth and seed production of A. artemisiifolia. 7. In heavily infested regions of Europe, A. artemisiifolia causes substantial crop-yield losses and its copious, highly allergenic pollen creates considerable public health problems. There is consensus among models that climate change will allow its northward and up-hill spread in Europe.
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Because natural selection is likely to act on multiple genes underlying a given phenotypic trait, we study here the potential effect of ongoing and past selection on the genetic diversity of human biological pathways. We first show that genes included in gene sets are generally under stronger selective constraints than other genes and that their evolutionary response is correlated. We then introduce a new procedure to detect selection at the pathway level based on a decomposition of the classical McDonald-Kreitman test extended to multiple genes. This new test, called 2DNS, detects outlier gene sets and takes into account past demographic effects and evolutionary constraints specific to gene sets. Selective forces acting on gene sets can be easily identified by a mere visual inspection of the position of the gene sets relative to their two-dimensional null distribution. We thus find several outlier gene sets that show signals of positive, balancing, or purifying selection but also others showing an ancient relaxation of selective constraints. The principle of the 2DNS test can also be applied to other genomic contrasts. For instance, the comparison of patterns of polymorphisms private to African and non-African populations reveals that most pathways show a higher proportion of nonsynonymous mutations in non-Africans than in Africans, potentially due to different demographic histories and selective pressures.
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Tutkielman tavoitteena on tutkia, mikä olisi parhaiten case-yritykselle sopiva menetelmä tulla tekemään kauppaa ulkomaan markkinoille. Kaikki yleiset kansainvälisille markkinoilletulomenetelmät esitetään ja niiden edut ja haitat tuodaan esille. Selvittäessä tehtävänantajayrityksen resurssit, odotukset ja vaatimukset todetaan, että yhteistyössä tehtävä markkinoilletulo on pätevin vaihtoehto. Tämän jälkeen valitaan parhaiten tarkoitukseen sopiva yritys ennalta valitusta yritysvaihtoehtojen ryhmästä ja testataan tämän yrityksen yhteistyösopivuus case-yrityksen kanssa. Yritysten välinen yhteistyösopivuus arvioidaan analysoimalla yritykset haastattelujen avulla ja tutkielmassa esitettyjen teorioiden avulla. Sopivuus todetaan hyväksi, kattaen 71 prosenttia analysoiduista kohdista. Kaksikymmentäyhdeksän prosenttia kohdista todetaan kohdiksi, joissa yritysten välinen yhteisymmärrys ei ole toimeksiantajayrityksen minimivaatimukset täyttävää. Näitä kohtia tullaan käyttämään suunnittelun pohjana kun suunnitellaan jatkoneuvotteluja yhteistyön käynnistämiseksi.