967 resultados para Cellular control mechanisms


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This article presents the continuities from the past -structural asymmetries and hyper-presidentialism- as well as the innovations of the new democratic Argentina. This mixture of continuity and innovation has contributed to the development of particular forms of intergovernmental relations which we call cross control mechanisms  and interference between the federal and provincial levels. This mixture also  contributes to the shining of subnational actors in national arenas and of the provincial party identities. These elements are what primarily determine the way  the democratic political game in Argentina has been structured, since the transition.

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En esta investigación se plantea que la convivencia entre las fotocopiadoras, las TIC, los proveedores y los usuarios de tecnologías en la Universidad del Rosario es problemática, ya que presentan diversos conjuntos de relaciones entre artefactos tecnológicos, grupos sociales, proyectos políticos internacionales, nacionales e institucionales, y mecanismos de control que se encuentran en relaciones de tensión y negociación permanente. La exploración de las relaciones permitió identificar que existe una deficiencia común entre los diversos grupos relacionados al uso de tecnologías en la educación, que es la falta de conocimiento sobre las prácticas de uso de artefactos tecnológicos. Por lo tanto, se planteó explorar a través de los proveedores y usuarios de tecnologías en la Universidad del Rosario, los principales elementos que conforman las prácticas de uso de artefactos tecnológicos. Los resultados del trabajo permitieron identificar que los principales elementos que caracterizan las prácticas de uso de artefactos tecnológicos se podrían categorizar en tres dimensiones: (1) las responsabilidades que demandan los artefactos tecnológicos a sus usuarios; (2) las tensiones políticas por el uso de artefactos tecnológicos y; (3) los modelos pedagógicos en el uso de artefactos tecnológicos.

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El presente trabajo tiene como finalidad caracterizar conceptos y elementos clave del caos y de la complejidad existente en la relación entre las organizaciones y la comunidad. Esta relación parte de la base de satisfacer las necesidades de los actores involucrados y, así mismo, mejorar el desempeño de cada uno, y contribuir al bienestar de la sociedad y a la perdurabilidad de las empresas. Para alcanzar el objetivo planteado, inicialmente se hace necesario contextualizar conceptos que estarán presentes durante todo el escrito. Por esto se expondrán términos como teoría de la complejidad, teoría del caos, los aspectos más representativos de la relación comunitaria y el marketing y su impacto en las comunidades. La teoría de la complejidad permitirá entender los sistemas como un todo, en donde las relaciones e interacciones de cada una de sus diferentes partes nos conducen a innumerables escenarios posibles. También se buscará entender la importancia de la relación organización-comunidad, ya que la comunidad puede jugar un papel determinante cuando las organizaciones se adaptan a los cambios. Es de suma importancia establecer relaciones estratégicas con la comunidad, entendiendo a la comunidad como un sistema o grupo social con determinadas características, que permitan tanto a las organizaciones como a la misma comunidad entender, comprender y satisfacer eficazmente las necesidades subyacentes y, así, llegar a establecer un entorno de retroalimentación continua y sostenibilidad a lo largo del tiempo. Actualmente, el funcionamiento del mundo ha cambiado en cierta medida, ya que antes la base del conocimiento se centraba en función del orden y la regularidad. Ahora, en cambio, se destaca la creatividad y la dinámica que son causadas por el desorden y la irregularidad presentes en los sistemas. El mundo se plantea como un grupo de innumerables sistemas auto-organizados, donde su funcionamiento puede provocar resultados impredecibles o aleatorios. La materia de complejidad en los sistemas se ha desarrollado por diferentes autores según aproximaciones desde diferentes ramas de la ciencia, como la cibernética, basada en los mecanismos de retroalimentación y control; desde la teoría general de los sistemas, que da énfasis en el dinamismo presente en los sistemas y cómo la organización está presente en su estructura. En el presente proyecto se realizará un estudio de tipo teórico-conceptual: se seleccionarán las bases de datos, fuentes de información y los documentos más representativos o que proporcionen la mayor información posible que permita el completo entendimiento de la investigación y de sus alcances propuestos. Es así que esta investigación busca aportar más elementos dentro de los diferentes estudios que pretenden explicar y mejorar la perdurabilidad de las empresas bajo las diferentes líneas de investigación. A través del tiempo, el GIPE ha ido evolucionando de acuerdo con los resultados de las investigaciones y se ha centrado en cuatro líneas de investigación: Liderazgo, Realidad, Estrategia y Gerencia. El proyecto de investigación “Relación de las organizaciones con el medio y marketing” hace parte de la línea de gerencia y busca identificar oportunidades gerenciales para las organizaciones que las acerquen al conocimiento y manejo de las áreas funcionales (Facultad de Administración, 2013). Además, el proyecto se adentra en las organizaciones en entornos complejos y su relación con la comunidad, y se observa así la organización como un ser vivo que contribuye al bienestar de la sociedad que, finalmente, es lo que garantiza su perdurabilidad.

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The characteristics of service independence and flexibility of ATM networks make the control problems of such networks very critical. One of the main challenges in ATM networks is to design traffic control mechanisms that enable both economically efficient use of the network resources and desired quality of service to higher layer applications. Window flow control mechanisms of traditional packet switched networks are not well suited to real time services, at the speeds envisaged for the future networks. In this work, the utilisation of the Probability of Congestion (PC) as a bandwidth decision parameter is presented. The validity of PC utilisation is compared with QOS parameters in buffer-less environments when only the cell loss ratio (CLR) parameter is relevant. The convolution algorithm is a good solution for CAC in ATM networks with small buffers. If the source characteristics are known, the actual CLR can be very well estimated. Furthermore, this estimation is always conservative, allowing the retention of the network performance guarantees. Several experiments have been carried out and investigated to explain the deviation between the proposed method and the simulation. Time parameters for burst length and different buffer sizes have been considered. Experiments to confine the limits of the burst length with respect to the buffer size conclude that a minimum buffer size is necessary to achieve adequate cell contention. Note that propagation delay is a no dismiss limit for long distance and interactive communications, then small buffer must be used in order to minimise delay. Under previous premises, the convolution approach is the most accurate method used in bandwidth allocation. This method gives enough accuracy in both homogeneous and heterogeneous networks. But, the convolution approach has a considerable computation cost and a high number of accumulated calculations. To overcome this drawbacks, a new method of evaluation is analysed: the Enhanced Convolution Approach (ECA). In ECA, traffic is grouped in classes of identical parameters. By using the multinomial distribution function instead of the formula-based convolution, a partial state corresponding to each class of traffic is obtained. Finally, the global state probabilities are evaluated by multi-convolution of the partial results. This method avoids accumulated calculations and saves storage requirements, specially in complex scenarios. Sorting is the dominant factor for the formula-based convolution, whereas cost evaluation is the dominant factor for the enhanced convolution. A set of cut-off mechanisms are introduced to reduce the complexity of the ECA evaluation. The ECA also computes the CLR for each j-class of traffic (CLRj), an expression for the CLRj evaluation is also presented. We can conclude that by combining the ECA method with cut-off mechanisms, utilisation of ECA in real-time CAC environments as a single level scheme is always possible.

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In recent years, exciting progress has been made towards unravelling the complex intraovarian control mechanisms that, in concert with systemic signals, coordinate the recruitment, selection and growth of follicles from the primordial stage through to ovulation and corpus luteum formation. A plethora of growth factors, many belonging to the transforming growth factor-beta (TGF-beta) superfamily, are expressed by ovarian somatic cells and oocytes in a developmental, stage-related manner and function as intraovarian regulators of folliculogenesis. Two such factors, bone morphogenetic proteins, RMP-4 and BMP-7, are expressed by ovarian stromal cells and/or theca cells and have recently been implicated as positive regulators of the primordial-to-primary follicle transition. In contrast, evidence indicates a negative role for anti-Mullerian hormone (AMH, also known as Mullerian-inhibiting substance) of pre-granulosa/granulosa cell origin in this key event and subsequent progression to the antral stage. Two other TGF-beta superfamily members, growth and differentiation factor-9 (GDF-9) and BMP-15 (also known as GDF-9B) are expressed in an oocyte-specific manner from a very early stage and play key roles in promoting follicle growth beyond the primary stage; mice with null mutations in the gdf-9 gene or ewes with inactivating mutations in gdf-9 or bmp-15 genes are infertile with follicle development arrested at the primary stage. Studies on later stages of follicle development indicate positive roles for granulosa cell-derived activin, BMP-2, -5 and -6, theca cell-derived BMP-2, -4 and -7 and oocyte-derived BMP-6 in promoting granulosa cell proliferation, follicle survival and prevention of premature luteinization and/or atresia. Concomitantly, activin, TGF-beta and several BMPs may exert paracrine actions on theca cells to attenuate LH-dependent androgen production in small to medium-size antral follicles. Dominant follicle selection in monovular species may depend on differential FSH sensitivity amongst a growing cohort of small antral follicles. Changes in intrafollicular activins, GDF-9, AMH and several BMPs may contribute to this selection process by modulating both FSH- and IGF-dependent signalling pathways in granulosa cells. Activin may also play a positive role in oocyte maturation and acquisition of developmental competence. in addition to its endocrine role to suppress FSH secretion, increased output of inhibin by the selected dominant follicle(s) may upregulate LH-induced androgen secretion that is required to sustain a high level of oestradiol secretion during the pre-ovulatory phase. Advances in our understanding of intraovarian regulatory mechanisms should facilitate the development of new approaches for monitoring and manipulating ovarian function and improving fertility in domesticated livestock, endangered species and man.

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The cyclin/cyclin-dependent kinase (Cdk) complexes and the Cdk inhibitors (CDKI) are crucial regulators of cell cycle progression in all eukaryotic cells. Using rat cardiac myocytes as a model system, this chapter provides a detailed account of methods that can be employed to measure both cyclin/Cdk activity in cells and the extent of CDKI inhibitory activity present in a particular cell type.

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Coronary artery disease is one of the most common heart pathologies. Restriction of blood flow to the heart by atherosclerotic lesions, leading to angina pectoris and myocardial infarction, damages the heart, resulting in impaired cardiac function. Damaged myocardium is replaced by scar tissue since surviving cardiomyocytes are unable to proliferate to replace lost heart tissue. Although narrowing of the coronary arteries can be treated successfully using coronary revascularisation procedures, re-occlusion of the treated vessels remains a significant clinical problem. Cell cycle control mechanisms are key in both the impaired cardiac repair by surviving cardiomyocytes and re-narrowing of treated vessels by maladaptive proliferation of vascular smooth muscle cells. Strategies targeting the cell cycle machinery in the heart and vasculature offer promise both for the improvement of cardiac repair following MI and the prevention of restenosis and bypass graft failure following revascularisation procedures.

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This paper presents a clocking pipeline technique referred to as a single-pulse pipeline (PP-Pipeline) and applies it to the problem of mapping pipelined circuits to a Field Programmable Gate Array (FPGA). A PP-pipeline replicates the operation of asynchronous micropipelined control mechanisms using synchronous-orientated logic resources commonly found in FPGA devices. Consequently, circuits with an asynchronous-like pipeline operation can be efficiently synthesized using a synchronous design methodology. The technique can be extended to include data-completion circuitry to take advantage of variable data-completion processing time in synchronous pipelined designs. It is also shown that the PP-pipeline reduces the clock tree power consumption of pipelined circuits. These potential applications are demonstrated by post-synthesis simulation of FPGA circuits. (C) 2004 Elsevier B.V. All rights reserved.

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The increasing amount of available expressed gene sequence data makes whole-transcriptome analysis of certain crop species possible. Potato currently has the second largest number of publicly available expressed sequence tag (EST) sequences among the Solanaceae. Most of these ESTs, plus other proprietary sequences, were combined and used to generate a unigene assembly. The set of 246,182 sequences produced 46,345 unigenes, which were used to design a 44K 60-mer oligo array (Potato Oligo Chip Initiative: POCI). In this study, we attempt to identify genes controlling and driving the process of tuber initiation and growth by implementing large-scale transcriptional changes using the newly developed POCI array. Major gene expression profiles could be identified exhibiting differential expression at key developmental stages. These profiles were associated with functional roles in cell division and growth. A subset of genes involved in the regulation of the cell cycle, based on their Gene Ontology classification, exhibit a clear transient upregulation at tuber onset indicating increased cell division during these stages. The POCI array allows the study of potato gene expression on a much broader level than previously possible and will greatly enhance analysis of transcriptional control mechanisms in a wide range of potato research areas. POCI sequence and annotation data are publicly available through the POCI database (http://pgrc.ipk-gatersleben.de/poci).

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The aim of this work is to review current knowledge relating the established cancer hallmark, sustained cell proliferation to the existence of chemicals present as low dose mixtures in the environment. Normal cell proliferation is under tight control, i.e. cells respond to a signal to proliferate, and although most cells continue to proliferate into adult life, the multiplication ceases once the stimulatory signal disappears or if the cells are exposed to growth inhibitory signals. Under such circumstances, normal cells remain quiescent until they are stimulated to resume further proliferation. In contrast, tumour cells are unable to halt proliferation, either when subjected to growth inhibitory signals or in the absence of growth stimulatory signals. Environmental chemicals with carcinogenic potential may cause sustained cell proliferation by interfering with some cell proliferation control mechanisms committing cells to an indefinite proliferative span.

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Existing urban meteorological networks have an important role to play as test beds for inexpensive and more sustainable measurement techniques that are now becoming possible in our increasingly smart cities. The Birmingham Urban Climate Laboratory (BUCL) is a near-real-time, high-resolution urban meteorological network (UMN) of automatic weather stations and inexpensive, nonstandard air temperature sensors. The network has recently been implemented with an initial focus on monitoring urban heat, infrastructure, and health applications. A number of UMNs exist worldwide; however, BUCL is novel in its density, the low-cost nature of the sensors, and the use of proprietary Wi-Fi networks. This paper provides an overview of the logistical aspects of implementing a UMN test bed at such a density, including selecting appropriate urban sites; testing and calibrating low-cost, nonstandard equipment; implementing strict quality-assurance/quality-control mechanisms (including metadata); and utilizing preexisting Wi-Fi networks to transmit data. Also included are visualizations of data collected by the network, including data from the July 2013 U.K. heatwave as well as highlighting potential applications. The paper is an open invitation to use the facility as a test bed for evaluating models and/or other nonstandard observation techniques such as those generated via crowdsourcing techniques.

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The auditor and the insitutionalization of distrust: the professionalization of external auditing in Sweden This paper addresses professionalization with a focus on trust, rather than on issues of power and competition. It contains a conceptual analysis of trust/confidence, as well as a case study of the professionalization of external auditing in Sweden. The conceptual analysis discusses the “time-binding” aspect of trust/confidence, and the significance of social control mechanisms related to “persons”, “roles”, “values” and “programs” for creating and sustaining trust/confidence. The case study focuses on the role of trust/confidence for the organization and professionalization of external auditing in Sweden, and in particular on the ways in which trust in auditors and auditing have been stabilized. The latter issue is dealt with through a discussion attempting to capture a historic displacement in three dimensions: from reliance on the auditor’spersonal reliability, to trust in the professional role; from trust in the individual discretion of certain persons to trust in the regulation of auditing as a standardized program; and finally, from trust in the values represented by individual auditors to trust in the institutionalized professional values.

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The phenotypic effect of a gene is normally described by the mean-difference between alternative genotypes. A gene may, however, also influence the phenotype by causing a difference in variance between genotypes. Here, we reanalyze a publicly available Arabidopsis thaliana dataset [1] and show that genetic variance heterogeneity appears to be as common as normal additive effects on a genomewide scale. The study also develops theory to estimate the contributions of variance differences between genotypes to the phenotypic variance, and this is used to show that individual loci can explain more than 20% of the phenotypic variance. Two well-studied systems, cellular control of molybdenum level by the ion-transporter MOT1 and flowering-time regulation by the FRI-FLC expression network, and a novel association for Leaf serration are used to illustrate the contribution of major individual loci, expression pathways, and gene-by-environment interactions to the genetic variance heterogeneity.

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A proposta deste trabalho consiste, primeiramente, em apresentar o pensamento de Michel Foucault quanto à instauração e existência da sociedade disciplinar. Apresenta ainda, inspirado na visão foucaultiana, uma análise do funcionamento de duas escolas públicas do 1o grau, a partir de alguns documentos. Tal análise pretende tornar explícitos os mecanismos e instrumentos da disciplina nas relações entre os elementos da escola, enfocando especialmente o papel do professor. Procuramos descrever a visão foucaultiana sobre a sociedade disciplinar, tomando seus estudos sobre as formas anteriores à disciplina, para melhor compreendêla. Tais objetivos foram determinados, portanto, pela necessidade de verificar a viabilidade de uma análise da complexa rede de produção de relações de poder na escola. Foi possível verificar a existência de um comprometimento dos atores da escola, na produção dos conhecimentos e das verdades que se fazem necessários à manutenção da ordem instaurada. Comprometimento este que se percebe na prática escolar, pelo uso de procedimentos que visam o alcance e continuidade dos efeitos de poder que essas relações trazem. O atendimento a mecanismos de controle que asseguram a função normalizadora da disciplina escolar, pode ser verificado na atribuição de papéis funcionais a cada profissional e, dentre estes, o professor. Ressalta-se, no entanto, os estreitos limites do campo de análise aqui utilizado, o que deixa antever as vantagens de utilização deste estudo a um universo de pesquisa mais abrangente, a fim de verificar o grau de generalidade das afirmações aqui contidas, a partir deste estudo particular.

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A proposta deste trabalho consiste, primeiramente, em apresentar o pensamento de Michel Foucault quanto à instauração e existência da sociedade disciplinar. Apresenta ainda, inspirado na visão foucaultiana, uma análise do funcionamento de duas escolas públicas do lo grau, a partir de alguns documentos. Tal análise pretende tornar explícitos os mecanismos e instrumentos da disciplina nas relações entre os elementos da escola, enfocando especialmente o papel do professor. Procuramos descrever a visão foucaultiana sobre a sociedade disciplinar, tomando seus estudos sobre as formas anteriores à disciplina, para melhor compreendê-la. Tais objetivos foram determinados, portanto, pela necessidade de verificar a viabilidade de uma análise da complexa rede de produção de relações de poder na escola. Foi possível verificar a existência de um comprometimento dos atores da escola, na produção dos co nhecimentos e das verdades que se fazem necessários à manutenção da ordem instaurada. Comprometimento este que se percebe na prática escolar, pelo uso de procedimentos que visam o alcance e continuidade dos efeitos de poder que essas relações trazem. O atendimento a mecanismos de controle que asseguram a função normalizadora da disciplina escolar, pode ser verificado na atribuição de papéis funcionais a cada profissional e, dentre estes, o professor. Ressalta-se, no entanto, os estreitos limites do campo de análise aqui utilizado, o que deixa antever as vantagens de utilização deste estudo a um universo de pesquisa mais abrangente, a fim de verificar o grau de generalidade das afirmações aqui contidas, a partir deste estudo particular.