925 resultados para Key feature
Resumo:
A key feature of ‘TESOL Quarterly’, a leading journal in the world of TESOL/applied linguistics, is its ‘Forum’ section which invites ‘responses and rebuttals’ from readers to any of its articles. These ‘responses or rebuttals’ form the focus of this research. In the interchanges between readers reacting to earlier research articles in TESOL Quarterly and authors responding to the said reaction I – examine the texts for evidence of genre-driven structure, whether shared between both ‘reaction’ and ‘response’ sections, or peculiar to each section, and attempt to determine the precise nature of the intended communicative purpose in particular and the implications for academic debate in general. The intended contribution of this thesis is to provide an analysis of how authors of research articles and their critics pursue their efforts beyond the research article which precipitated these exchanges in order to be recognized by their discourse community as, in the terminology of Swales (1981:51), ‘Primary Knowers’. Awareness of any principled generic process identified in this thesis may be of significance to practitioners in the applied linguistics community in their quest to establish academic reputation and in their pursuit of professional development. These findings may also be of use in triggering productive community discussion as a result of the questions they raise concerning the present nature of academic debate. Looking beyond the construction and status of the texts themselves, I inquire into the kind of ideational and social organization such exchanges keep in place and examine an alternative view of interaction. This study breaks new ground in two major ways. To the best of my knowledge, it is the first exploration of a bipartite, intertextual structure laying claim to genre status. Secondly, in its recourse to the comments of the writers’ themselves rather than relying exclusively on the evidence of their texts, as is the case with most studies of genre, this thesis offers an expanded opportunity to discuss perhaps the most interesting aspects of genre analysis – the light it throws on social ends and the role of genre in determining the nature of current academic debate as it here emerges.
Resumo:
Over the last three decades foreign direct investment (FDI) has become the most visible driver of globalisation. It has grown faster than world output and international trade and now reports world annual flows exceeding 1,000 billion US dollars. In this period, Germany has undergone significant changes in order to play an important role in the globalisation process. Apart from being a member state of the European Union (EU) whose key feature is the free flow of trade, investment and labour, the re-unification of East and West Germany in 1990 has been a significant development. This in effect has meant that East Germany as well as other Eastern European nations opened up to foreign investment for the first time. In this period, Germany has attracted in excess of 10 per cent of inward FDI into the EU and invested around 15 per cent of all FDI in the EU. This thesis explores empirically the potential impact of FDI on firms operating in and investing from Germany over a ten year period. Using panel data at the firm-level it concentrates on three areas relating to FDI. Firstly, it considers whether foreign-owned firms are more productive than German multinational firms and German non-multinational firms. Secondly, the thesis considers the impact of German investments abroad on domestic productivity. Finally, employment effects emanating from outward high-tech FDI are estimated for the leading OECD (Organisation of Economic Co-operation and Development) countries, namely Germany, Belgium, France, the Netherlands, Sweden, the United Kingdom and Japan. The findings of the first analysis indicate that while foreign-owned firms are generally more productive than German non-multinationals, there is no clear cut difference between foreign-owned firms and German multinationals. These differences would not have been uncovered, had the analysis compared foreign firms with all domestic firms. Equally, location within Germany is also important, as this productivity gap is more pronounced for firms which are located in the Eastern states. The findings of the second analysis suggest that engaging in outward FDI has an overall positive effect on the parent firm's productivity at home. Finally, results of the third analysis show that an expansion of high-tech offshoring activities by OECD multinationals (MNEs) is not associated with any reduction in employment at home.
Resumo:
Wireless Mesh Networks (WMNs) have emerged as a key technology for the next generation of wireless networking. Instead of being another type of ad-hoc networking, WMNs diversify the capabilities of ad-hoc networks. Several protocols that work over WMNs include IEEE 802.11a/b/g, 802.15, 802.16 and LTE-Advanced. To bring about a high throughput under varying conditions, these protocols have to adapt their transmission rate. In this paper, we have proposed a scheme to improve channel conditions by performing rate adaptation along with multiple packet transmission using packet loss and physical layer condition. Dynamic monitoring, multiple packet transmission and adaptation to changes in channel quality by adjusting the packet transmission rates according to certain optimization criteria provided greater throughput. The key feature of the proposed method is the combination of the following two factors: 1) detection of intrinsic channel conditions by measuring the fluctuation of noise to signal ratio via the standard deviation, and 2) the detection of packet loss induced through congestion. We have shown that the use of such techniques in a WMN can significantly improve performance in terms of the packet sending rate. The effectiveness of the proposed method was demonstrated in a simulated wireless network testbed via packet-level simulation.
Resumo:
Using the integrable nonlinear Schrodinger equation (NLSE) as a channel model, we describe the application of nonlinear spectral management for effective mitigation of all nonlinear distortions induced by the fiber Kerr effect. Our approach is a modification and substantial development of the so-called eigenvalue communication idea first presented in A. Hasegawa, T. Nyu, J. Lightwave Technol. 11, 395 (1993). The key feature of the nonlinear Fourier transform (inverse scattering transform) method is that for the NLSE, any input signal can be decomposed into the so-called scattering data (nonlinear spectrum), which evolve in a trivial manner, similar to the evolution of Fourier components in linear equations. We consider here a practically important weakly nonlinear transmission regime and propose a general method of the effective encoding/modulation of the nonlinear spectrum: The machinery of our approach is based on the recursive Fourier-type integration of the input profile and, thus, can be considered for electronic or all-optical implementations. We also present a novel concept of nonlinear spectral pre-compensation, or in other terms, an effective nonlinear spectral pre-equalization. The proposed general technique is then illustrated through particular analytical results available for the transmission of a segment of the orthogonal frequency division multiplexing (OFDM) formatted pattern, and through WDM input based on Gaussian pulses. Finally, the robustness of the method against the amplifier spontaneous emission is demonstrated, and the general numerical complexity of the nonlinear spectrum usage is discussed. © 2013 Optical Society of America.
Resumo:
Wireless Mesh Networks (WMNs) have emerged as a key technology for the next generation of wireless networking. Instead of being another type of ad-hoc networking, WMNs diversify the capabilities of ad-hoc networks. Several protocols that work over WMNs include IEEE 802.11a/b/g, 802.15, 802.16 and LTE-Advanced. To bring about a high throughput under varying conditions, these protocols have to adapt their transmission rate. This paper proposes a scheme to improve channel conditions by performing rate adaptation along with multiple packet transmission using packet loss and physical layer condition. Dynamic monitoring, multiple packet transmission and adaptation to changes in channel quality by adjusting the packet transmission rates according to certain optimization criteria provided greater throughput. The key feature of the proposed method is the combination of the following two factors: 1) detection of intrinsic channel conditions by measuring the fluctuation of noise to signal ratio via the standard deviation, and 2) the detection of packet loss induced through congestion. The authors show that the use of such techniques in a WMN can significantly improve performance in terms of the packet sending rate. The effectiveness of the proposed method was demonstrated in a simulated wireless network testbed via packet-level simulation.
Resumo:
Marine phytoplankton can evolve rapidly when confronted with aspects of climate change because of their large population sizes and fast generation times. Despite this, the importance of environment fluctuations, a key feature of climate change, has received little attention-selection experiments with marine phytoplankton are usually carried out in stable environments and use single or few representatives of a species, genus or functional group. Here we investigate whether and by how much environmental fluctuations contribute to changes in ecologically important phytoplankton traits such as C:N ratios and cell size, and test the variability of changes in these traits within the globally distributed species Ostreococcus. We have evolved 16 physiologically distinct lineages of Ostreococcus at stable high CO2 (1031±87?µatm CO2, SH) and fluctuating high CO2 (1012±244?µatm CO2, FH) for 400 generations. We find that although both fluctuation and high CO2 drive evolution, FH-evolved lineages are smaller, have reduced C:N ratios and respond more strongly to further increases in CO2 than do SH-evolved lineages. This indicates that environmental fluctuations are an important factor to consider when predicting how the characteristics of future phytoplankton populations will have an impact on biogeochemical cycles and higher trophic levels in marine food webs.
Resumo:
This article analyzes the relationship between employment status (ES), on one hand, and self-rated health and psychological distress, on the other, in the context of the Great Recession beginning in 2008. For this purpose, it is necessary to move beyond the employment/unemployment dichotomy characteristics of previous theories and research concerning the relationship between the labor market, recession, and health. The authors use data from the Spanish National Health Surveys in 2006 (n = 15,128), before the crisis, and in 2012 (n = 11,124), when its consequences had taken effect. The results of the regression analysis indicate a structural change in the relationship between ES and health. Health inequality patterns changed during the crisis, with increased deterioration in the health of unemployed, especially the long-term unemployed, and self-employed workers. Health inequalities were reduced for temporary workers. The results support the idea that the structure of the association between ES and health varies according to the economic cycle. The association between recession, ES, and health would be directly related to the specific characteristics of the economic and employment contexts under study. In the Spanish case, labor market segmentation processes based on numerical flexibility—a key feature of the Mediterranean Variety of Capitalism—may explain the results obtained.
Resumo:
CD4+ T cells play a crucial in the adaptive immune system. They function as the central hub to orchestrate the rest of immunity: CD4+ T cells are essential governing machinery in antibacterial and antiviral responses by facilitating B cell affinity maturation and coordinating the innate and adaptive immune systems to boost the overall immune outcome; on the contrary, hyperactivation of the inflammatory lineages of CD4+ T cells, as well as the impairments of suppressive CD4+ regulatory T cells, are the etiology of various autoimmunity and inflammatory diseases. The broad role of CD4+ T cells in both physiological and pathological contexts prompted me to explore the modulation of CD4+ T cells on the molecular level.
microRNAs (miRNAs) are small RNA molecules capable of regulating gene expression post-transcriptionally. miRNAs have been shown to exert substantial regulatory effects on CD4+ T cell activation, differentiation and helper function. Specifically, my lab has previously established the function of the miR-17-92 cluster in Th1 differentiation and anti-tumor responses. Here, I further analyzed the role of this miRNA cluster in Th17 differentiation, specifically, in the context of autoimmune diseases. Using both gain- and loss-of-function approaches, I demonstrated that miRNAs in miR-17-92, specifically, miR-17 and miR-19b in this cluster, is a crucial promoter of Th17 differentiation. Consequently, loss of miR-17-92 expression in T cells mitigated the progression of experimental autoimmune encephalomyelitis and T cell-induced colitis. In combination with my previous data, the molecular dissection of this cluster establishes that miR-19b and miR-17 play a comprehensive role in promoting multiple aspects of inflammatory T cell responses, which underscore them as potential targets for oligonucleotide-based therapy in treating autoimmune diseases.
To systematically study miRNA regulation in effector CD4+ T cells, I devised a large-scale miRNAome profiling to track in vivo miRNA changes in antigen-specific CD4+ T cells activated by Listeria challenge. From this screening, I identified that miR-23a expression tightly correlates with CD4+ effector expansion. Ectopic expression and genetic deletion strategies validated that miR-23a was required for antigen-stimulated effector CD4+ T cell survival in vitro and in vivo. I further determined that miR-23a targets Ppif, a gatekeeper of mitochondrial reactive oxygen species (ROS) release that protects CD4+ T cells from necrosis. Necrosis is a type of cell death that provokes inflammation, and it is prominently triggered by ROS release and its consequent oxidative stress. My finding that miR-23a curbs ROS-mediated necrosis highlights the essential role of this miRNA in maintaining immune homeostasis.
A key feature of miRNAs is their ability to modulate different biological aspects in different cell populations. Previously, my lab found that miR-23a potently suppresses CD8+ T cell cytotoxicity by restricting BLIMP1 expression. Since BLIMP1 has been found to inhibit T follicular helper (Tfh) differentiation by antagonizing the master transcription factor BCL6, I investigated whether miR-23a is also involved in Tfh differentiation. However, I found that miR-23a does not target BLIMP1 in CD4+ T cells and loss of miR-23a even fostered Tfh differentiation. This data indicate that miR-23a may target other pathways in CD4+ T cells regarding the Tfh differentiation pathway.
Although the lineage identity and regulatory networks for Tfh cells have been defined, the differentiation path of Tfh cells remains elusive. Two models have been proposed to explain the differentiation process of Tfh cells: in the parallel differentiation model, the Tfh lineage is segregated from other effector lineages at the early stage of antigen activation; alternatively, the sequential differentiation model suggests that naïve CD4+ T cells first differentiate into various effector lineages, then further program into Tfh cells. To address this question, I developed a novel in vitro co-culture system that employed antigen-specific CD4+ T cells, naïve B cells presenting cognate T cell antigen and BAFF-producing feeder cells to mimic germinal center. Using this system, I were able to robustly generate GC-like B cells. Notably, well-differentiated Th1 or Th2 effector cells also quickly acquired Tfh phenotype and function during in vitro co-culture, which suggested a sequential differentiation path for Tfh cells. To examine this path in vivo, under conditions of classical Th1- or Th2-type immunizations, I employed a TCRβ repertoire sequencing technique to track the clonotype origin of Tfh cells. Under both Th1- and Th2- immunization conditions, I observed profound repertoire overlaps between the Teff and Tfh populations, which strongly supports the proposed sequential differentiation model. Therefore, my studies establish a new platform to conveniently study Tfh-GC B cell interactions and provide insights into Tfh differentiation processes.
Resumo:
The goal of this research is to produce a system for powering medical implants to increase the lifetime of the implanted devices and reduce the battery size. The system consists of a number of elements – the piezoelectric material for generating power, the device design, the circuit for rectification and energy storage. The piezoelectric material is analysed and a process for producing a repeatable high quality piezoelectric material is described. A full width half maximum (FWHM) of the rocking curve X-Ray diffraction (XRD) scan of between ~1.5° to ~1.7° for test wafers was achieved. This is state of the art for AlN on silicon and means devices with good piezoelectric constants can be fabricated. Finite element modelling FEM) was used to design the structures for energy harvesting. The models developed in this work were established to have an accuracy better than 5% in terms of the difference between measured and modelled results. Devices made from this material were analysed for power harvesting ability as well as the effect that they have on the flow of liquid which is an important consideration for implantable devices. The FEM results are compared to experimental results from laser Doppler vibrometry (LDV), magnetic shaker and perfusion machine tests. The rectifying circuitry for the energy harvester was also investigated. The final solution uses multiple devices to provide the power to augment the battery and so this was a key feature to be considered. Many circuits were examined and a solution based on a fully autonomous circuit was advanced. This circuit was analysed for use with multiple low power inputs similar to the results from previous investigations into the energy harvesting devices. Polymer materials were also studied for use as a substitute for the piezoelectric material as well as the substrate because silicon is more brittle.
Resumo:
Annual precipitation for the last 2,500 years was reconstructed for northeastern Qinghai from living and archaeological juniper trees. A dominant feature of the precipitation of this area is a high degree of variability in mean rainfall at annual, decadal, and centennial scales, with many wet and dry periods that are corroborated by other paleoclimatic indicators. Reconstructed values of annual precipitation vary mostly from 100 to 300 mm and thus are no different from the modern instrumental record in Dulan. However, relatively dry years with below-average precipitation occurred more frequently in the past than in the present. Periods of relatively dry years occurred during 74-25 BC, AD 51-375, 426-500, 526-575, 626-700, 1100-1225, 1251-1325, 1451-1525, 1651-1750 and 1801-1825. Periods with a relatively wet climate occurred during AD 376-425, 576-625, 951-1050, 1351-1375, 1551-1600 and the present. This variability is probably related to latitudinal positions of winter frontal storms. Another key feature of precipitation in this area is an apparently direct relationship between interannual variability in rainfall with temperature, whereby increased warming in the future might lead to increased flooding and droughts. Such increased climatic variability might then impact human societies of the area, much as the climate has done for the past 2,500 years.
Resumo:
A key feature of Greece is the large amount of historical and archaeological records. The sedimentary record of the Etoliko Lagoon, Aetolia, Western Greece, offers an ideal opportunity to study human-environment interaction and to disentangle natural and anthropogenic imprints in the sedimentary record. By applying an interdisciplinary approach of combining geoscientific methods (XRF, LOI, grain size analysis) with archaeological and historical records, the 8.8 m long sedimentary sequence ETO1C reveals the palaeoenvironmental history of the lagoon and its catchment since 11,670 cal BP. With a thorough chronology based on 14C age-depth-modelling including varve counting, different evolutionary stages were put in a chronological context. These stages include a lake period (11,670-8310 cal BP) followed by a period of sporadic saltwater intrusion (8310-1350 cal BP) as a result of continuing transgression. Phases of limnic predominance associated with freshwater inflow of episodically activated distributaries (around 5230 cal BP) still occurred. By 1350 cal BP, ongoing sea level rise had connected the lagoons of Etoliko and Messolonghi and freshwater influence had ceased. With the onset of settlement activity in the Late Helladic (1700-1100 cal BC) humans took advantage of the prevailing environmental landscape. A sudden increase in coarse sedimentation correlates with the history of human occupation with its peak of prosperity from the Late Helladic until the end of the Hellenistic Period (30 cal BC).
Resumo:
Industrial land development has become a key feature of urbanization in Greater Jakarta, one of the largest metropolitan areas in Southeast Asia. Following Suharto’s marketoriented policy measures in the late 1980s, private developers have dominated the land development projects in Greater Jakarta. The article investigates the extent to which these private industrial centers have effectively reduced the domination of Jakarta in shaping the entire metropolitan structure. The analysis indicates that major suburban industrial centers have captured most of the manufacturing employment that has dispersed from Jakarta. The industrial centers have now increasingly specialized and diversified. It is likely that a polycentric metropolitan structure will emerge in the future.
Resumo:
This paper follows the emotional management of lone, independent women travellers as they move through tourist spaces, based on my doctoral research Embodiment and Emotion in the experiences of independent women tourists (2012). Specifically, this paper will focus on ‘gendering happiness’ by arguing that women travellers are significantly compelled to feel and display characteristics of happiness, humour and ‘learning to be Zen’ in order to be successful travellers. The imperative to become, and remain, happy and humorous in the face of embodied, emotional and gendered constraints is a key feature of women’s reflections of their travelling experiences, mirroring the recent emergence of literature into happiness and positive thinking within feminist theory (Ehrenreich 2010, Ahmed 2010). Negotiating ‘bad’ emotions provides a powerful insight into the perceptions of women travellers; to remain happy can mask problematic power relations and other forms of resistance. This is not to say that emotional negotiation is not partly a form of effective resistance, rather, I wish to make room for the freedom to be unhappy and angry in travelling space without feeling failure for not achieving a successful travelling identity.
Resumo:
The mechanisms involved in the progression from monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma (SMM) to malignant multiple myeloma (MM) and plasma cell leukemia (PCL) are poorly understood but believed to involve the sequential acquisition of genetic hits. We performed exome and whole-genome sequencing on a series of MGUS (n=4), high-risk (HR)SMM (n=4), MM (n=26) and PCL (n=2) samples, including four cases who transformed from HR-SMM to MM, to determine the genetic factors that drive progression of disease. The pattern and number of non-synonymous mutations show that the MGUS disease stage is less genetically complex than MM, and HR-SMM is similar to presenting MM. Intraclonal heterogeneity is present at all stages and using cases of HR-SMM, which transformed to MM, we show that intraclonal heterogeneity is a typical feature of the disease. At the HR-SMM stage of disease, the majority of the genetic changes necessary to give rise to MM are already present. These data suggest that clonal progression is the key feature of transformation of HR-SMM to MM and as such the invasive clinically predominant clone typical of MM is already present at the SMM stage and would be amenable to therapeutic intervention at that stage.
Resumo:
The current structure of the health and social care system in Northern Ireland has its origins in the Review of Public Administration (RPA) which was initiated by the Northern Ireland Executive in June 2002. The purpose of RPA was to review Northern Ireland’s system of public administration with a view to putting in place a modern, citizen-centred, accountable and high quality system of public administration. The structure was designed to be more streamlined and accountable and aimed at maximising resources for front-line services and ensuring that people have access to high quality health and social care. Another key feature is the placement of public health and wellbeing firmly at the centre of the system, with a greater emphasis on prevention and support for vulnerable people to live independently in the community for as long as possible.