12,200 research outputs found

    BKM Lie superalgebra for the Z_5 orbifolded CHL string

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    We study the Z_5-orbifolding of the CHL string theory by explicitly constructing the modular form tilde{Phi}_2 generating the degeneracies of the 1/4-BPS states in the theory. Since the additive seed for the sum form is a weak Jacobi form in this case, a mismatch is found between the modular forms generated from the additive lift and the product form derived from threshold corrections. We also construct the BKM Lie superalgebra, tilde{G}_5, corresponding to the modular form tilde{Delta}_1 (Z) = tilde{Phi}_2 (Z)^{1/2} which happens to be a hyperbolic algebra. This is the first occurrence of a hyperbolic BKM Lie superalgebra. We also study the walls of marginal stability of this theory in detail, and extend the arithmetic structure found by Cheng and Dabholkar for the N=1,2,3 orbifoldings to the N=4,5 and 6 models, all of which have an infinite number of walls in the fundamental domain. We find that analogous to the Stern-Brocot tree, which generated the intercepts of the walls on the real line, the intercepts for the N >3 cases are generated by linear recurrence relations. Using the correspondence between the walls of marginal stability and the walls of the Weyl chamber of the corresponding BKM Lie superalgebra, we propose the Cartan matrices for the BKM Lie superalgebras corresponding to the N=5 and 6 models.Comment: 30 pages, 2 figure

    Enhanced mobility for pentacene TFT built on NH3-annealed thermally grown SiO2

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    We have enhanced the mobility of pentacene OTFTs using NH 3-annealed SiO2 as gate dielectric and this annealing method is often applied in the semiconductor industry for inorganic transistors. The device has field-effect mobility higher than 0.5 cm2/Vs, with on/off current ratio larger than 106, and subthreshold slope less than 2.5 V per decade. When compared with the control sample, which uses N 2-annealed SiO2, the mobility of the proposed pentacene OTFT increases by over 50%. © 2005 IEEE.published_or_final_versio

    A rapid response to the COVID-19 outbreak: the meta-evidence project

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    Early in the pandemic, as scientific reports and preliminary research on both clinical and public health aspectsof COVID-19 were rapidly generated, we recognised the need for a dynamic, interactive tool that could captureand collate emerging evidence sources to inform research and decision-making efforts. In particular, we observed that numerous similar research efforts across the globe were happening in parallel - prompting an urgent need to connect research teams with each other and maximize research efficiency. Our colleagues in China provided daily translations of emerging evidence to aid networking between research groups working across the world. Here we describe how the meta-evidence project met daily and ongoing challenges and what was learned as a result. We describe the benefit of finding ways to instead work with better resourced teams and promote collective and open efforts to synthesise the evidence, which in the end, outweighed the considerable costs

    Intraindividual association between shift work and risk of drinking problems: Data from the Finnish Public Sector Cohort

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    OBJECTIVES: Studies concerning the association between shift work and drinking problems showed inconsistent results. We used data from a large occupational cohort to examine the association between shift work and different types of drinking behaviour. METHODS: A total of 93 121 non-abstinent workers from the Finnish Public Sector Study were enrolled in the study. Six waves of survey data were collected between 2000 and 2017. Work schedules were categorised as regular day, non-night shift and night shift work, and shift intensities were calculated from registered working hour data. Two indicators of adverse drinking behaviour were measured: at-risk drinking (>7 and >14 drinks per week in women and men, respectively) and high-intensity drinking (measured as pass-out experience). Intraindividual analysis was conducted using fixed-effects regression to examine the association between shift work and drinking behaviours. RESULTS: Compared with regular day work, night shift work was associated with an increased risk of high-intensity drinking (OR 1.28, 95% CI 1.07 to 1.52) but a lower risk of at-risk drinking (OR 0.85, 95% CI 0.74 to 0.99). Shift workers who worked long shifts had a lower risk of at-risk drinking compared with those who rarely worked long shifts (OR 0.58, 95% CI 0.37 to 0.93). CONCLUSIONS: Associations between shift work and alcohol use vary according to drinking patterns. Workers engaged in high-intensity drinking more often during night shift schedules compared with day work, but did not drink averagely higher volume

    Performance of large-size superconducting coil in 0.21T MRI system

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    A high-temperature superconductor (HTS) was used on magnetic resonance imaging (MRI) receiver coils to improve image quality because of its intrinsic low electrical resistivity [1], [2]. Typical HTS coils are surface coils made of HTS thin-film wafers. Their applications are severely limited by the field of view (FOV) of the surface coil configuration, and the improvement in image quality by HTS coil is also reduced as the ratio of sample noise to coil noise increases. Therefore, previous HTS coils are usually used to image small in vitro samples, small animals, or peripheral human anatomies [3]-[5]. We used large-size HTS coils (2.5-, 3.5-, and 5.5-in mean diameter) to enhance the FOV and we evaluated their performance through phantom and human MR images. Comparisons were made among HTS surface coils, copper surface coils, and cool copper surface coils in terms of the signal-to-noise ratio (SNR) and sensitivity profile of the images. A theoretical model prediction was also used to compare against the experimental result. We then selected several human body parts, including the wrist, feet, and head, to illustrate the advantage of HTS coil over copper coil when used in human imaging. The results show an SNR gain of 200% for 5.5-in HTS coil versus same size copper coils, while for 2.5- and 3.5-in coils it is 250%. We also address the various factors that affect the performance of large size HTS coils, including the coil-to-sample spacing due to cryogenic probe and the coil-loading effect.published_or_final_versio

    What is the evidence for the contribution of forests to poverty alleviation? A systematic map protocol

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.Background: Forests provide an essential resource that support the livelihoods of an estimated 20% of the global population. Forests are thought to serve in three primary roles to support livelihoods: subsistence, safety nets, and pathways to prosperity. While we have a working understanding of how poor people depend on forests in individual sites and countries, much of this evidence is dispersed and not easily accessible. Thus, while the importance of forest ecosystems and resources to contribute to poverty alleviation has been increasingly emphasized in international policies, conservation and development initiatives and investments- the strength of evidence to support how forests can affect poverty outcomes is still unclear. This study takes a systematic mapping approach to scope, identify and describe studies that measure the effect of forest-based activities on poverty outcomes at local and regional scales. This effort builds upon an existing systematic map on linkages between conservation and human well-being in order to make this process more efficient. We will conduct a refined and updated search strategy pertinent to forests-poverty linkages to glean additional evidence from studies outside the scope of the original map. Results of this study can be used for informing conservation and development policy and practices in global forest ecosystems and highlight evidence gaps where future primary studies and systematic reviews can add value. Methods: We build upon the search strategy outlined in McKinnon et al. (Environ Evid 1-25, 2016) and expand our search to cover a total of 7 bibliographic databases, 15 organizational websites, 8 existing systematic reviews and maps, and evidence gap maps, and solicit key informants. All searches will be conducted in English and encompass all nations. Search results will be screened at title, abstract, and full text levels, recording both the number of excluded articles and reasons for exclusion. Full text assessment will be conducted on all included article and extracted data will be reported in a narrative review that will summarize trends in the evidence, report any knowledge gaps and gluts, and provide insight for policy, practice and future research. The data from this systematic map will be made available as well, through an open access, searchable data portal and visualization tool.We are grateful for funding support from the Program on Forests (PROFOR) (SA, SO, SC, RG) and the USDA National Institute of Food and Agriculture, Hatch Project #1009327 (DM)

    The Regge Limit for Green Functions in Conformal Field Theory

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    We define a Regge limit for off-shell Green functions in quantum field theory, and study it in the particular case of conformal field theories (CFT). Our limit differs from that defined in arXiv:0801.3002, the latter being only a particular corner of the Regge regime. By studying the limit for free CFTs, we are able to reproduce the Low-Nussinov, BFKL approach to the pomeron at weak coupling. The dominance of Feynman graphs where only two high momentum lines are exchanged in the t-channel, follows simply from the free field analysis. We can then define the BFKL kernel in terms of the two point function of a simple light-like bilocal operator. We also include a brief discussion of the gravity dual predictions for the Regge limit at strong coupling.Comment: 23 pages 2 figures, v2: Clarification of relation of the Regge limit defined here and previous work in CFT. Clarification of causal orderings in the limit. References adde

    A computational framework to emulate the human perspective in flow cytometric data analysis

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    Background: In recent years, intense research efforts have focused on developing methods for automated flow cytometric data analysis. However, while designing such applications, little or no attention has been paid to the human perspective that is absolutely central to the manual gating process of identifying and characterizing cell populations. In particular, the assumption of many common techniques that cell populations could be modeled reliably with pre-specified distributions may not hold true in real-life samples, which can have populations of arbitrary shapes and considerable inter-sample variation. <p/>Results: To address this, we developed a new framework flowScape for emulating certain key aspects of the human perspective in analyzing flow data, which we implemented in multiple steps. First, flowScape begins with creating a mathematically rigorous map of the high-dimensional flow data landscape based on dense and sparse regions defined by relative concentrations of events around modes. In the second step, these modal clusters are connected with a global hierarchical structure. This representation allows flowScape to perform ridgeline analysis for both traversing the landscape and isolating cell populations at different levels of resolution. Finally, we extended manual gating with a new capacity for constructing templates that can identify target populations in terms of their relative parameters, as opposed to the more commonly used absolute or physical parameters. This allows flowScape to apply such templates in batch mode for detecting the corresponding populations in a flexible, sample-specific manner. We also demonstrated different applications of our framework to flow data analysis and show its superiority over other analytical methods. <p/>Conclusions: The human perspective, built on top of intuition and experience, is a very important component of flow cytometric data analysis. By emulating some of its approaches and extending these with automation and rigor, flowScape provides a flexible and robust framework for computational cytomics

    Oral drug delivery strategies for development of poorly water soluble drugs in paediatric patient population

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    Selecting the appropriate formulation and solubility-enabling technology for poorly water soluble drugs is an essential element in the development of formulations for paediatric patients. Different methodologies and structured strategies are available to select a suitable approach and guide formulation scientists for development of adult formulations. However, there is paucity of available literature for selection of technology and overcoming the challenges in paediatric formulation development. The need for flexible dosing, and the limited knowledge of the safety of many formulation excipients in paediatric subjects, impose significant constraints and in some instances require adaptation of the approaches taken to formulating these drugs for the adult population. Selection of the best drug delivery system for paediatrics requires an efficient, systematic approach that considers a drug's physical and chemical properties and the targeted patient population's requirements. This review is a step towards development of a strategy for the design of solubility enhancing paediatric formulations of highly insoluble drugs. The aim of this review is to provide an overview of different approaches and strategies to consider in order to assist development of paediatric formulation for poorly water-soluble drugs with the provision of examples of some marketed products. In addition, it provides recommendations to overcome the range of challenges posed by these strategies and adaptations of the adult approach/product presentation required to enable paediatric drug development and administration

    Asymptomatic members with SOD1 mutation in a large kindred with familial amyotrophic lateral sclerosis have abnormal water diffusion characterisitcs

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    DTI was carried out in FALS/SALS patients and familial members with SOD1 mutation (AFALS) who may be in a pre-symptomatic phase of ALS. The changes in FA and TT were investigated in CBT/CST and in whole brain. In FALS/SALS, diffusion pattern changes were found in cerebral peduncle, internal capsule, sub-cortical white matter, cerebellum and frontal lobe while in AFALS, abnormal pattern could also be detected in the cerebral peduncle, cerebellum and frontal lobe but with a smaller extent. Our study indicates that DTI can show early diffusion changes in members with SOD1 mutation in FALS prior to symptom-onset.published_or_final_versio
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