3,133 research outputs found
On Asymptotic Symmetries of 3d Extended Supergravities
We study asymptotic symmetry algebras for classes of three dimensional
supergravities with and without cosmological constant. In the first part we
generalise some of the non-Dirichlet boundary conditions of gravity to
extended supergravity theories, and compute their asymptotic symmetries. In
particular, we show that the boundary conditions proposed to holographically
describe the chiral induced gravity and Liouville gravity do admit extension to
the supergravity contexts with appropriate superalgebras as their asymptotic
symmetry algebras. In the second part we consider generalisation of the 3d
computation to extended supergravities without cosmological constant, and
show that their asymptotic symmetry algebras provide examples of nonlinear
extended superalgebras containing the algebra
Holographic chiral induced W-gravities
We study boundary conditions for 3-dimensional higher spin gravity that admit
asymptotic symmetry algebras expected of 2-dimensional induced higher spin
theories in the light cone gauge. For the higher spin theory based on sl(3, R)
plus sl(3,R) algebra, our boundary conditions give rise to one copy of
classical W3 and a copy of sl(3,R) or su(1,2) Kac-Moody symmetry algebra. We
propose that the higher spin theories with these boundary conditions describe
appropriate chiral induced W-gravity theories on the boundary. We also consider
boundary conditions of spin-3 higher spin gravity that admit u(1) plus u(1)
current algebra.Comment: 19 page
Practical guidelines for modelling post-entry spread in invasion ecology
In this article we review a variety of methods to enable understanding and modelling the spread of a pest or pathogen post-entry. Building upon our experience of multidisciplinary research in this area, we propose practical guidelines and a framework for model development, to help with the application of mathematical modelling in the field of invasion ecology for post-entry spread. We evaluate the pros and cons of a range of methods, including references to examples of the methods in practice. We also show how issues of data deficiency and uncertainty can be addressed. The aim is to provide guidance to the reader on the most suitable elements to include in a model of post-entry dispersal in a risk assessment, under differing circumstances. We identify both the strengths and weaknesses of different methods and their application as part of a holistic, multidisciplinary approach to biosecurity research
An sl(2, R) current algebra from AdS_3 gravity
We provide a set of chiral boundary conditions for three-dimensional gravity
that allow for asymptotic symmetries identical to those of two-dimensional
induced gravity in light-cone gauge considered by Polyakov. These are the most
general boundary conditions consistent with the boundary terms introduced by
Compere, Song and Strominger recently. We show that the asymptotic symmetry
algebra of our boundary conditions is an sl(2,R) current algebra with level
given by c/6. The fully non-linear solution in Fefferman--Graham coordinates is
also provided along with its charges.Comment: 8 page
A Translational Approach to Modeling Unique Aspects of Germ Cell Development During Self-Organization of the Primate Embryo
The specification of germ cells during embryonic development is vital not only for the development of an organism, but quite literally for the survival and propagation of its entire species. Recent work has demonstrated that several aspects of human primordial germ cell (hPGC) development are specific to primates, necessitating model systems and in vivo validation that is also species specific. In this work, a synthesis of in vitro and in vivo techniques is used to investigate hPGC specification within a human embryonic stem cell model of a gastrulating embryo known as a gastruloid. An hPGC transcriptomic signature that indicates migratory potential via canonical and novel mechanisms is indicated, raising several potential candidates for further investigation into the under-studied migratory phase of germ cell development. We seek to generate validation assays of hPGC function in an embryonic context by investigating migratory potential in grafts to the chick embryo, and demonstrate that despite significant differences between chick and human routes of migration in vivo, human in vitro-derived PGCs are in fact able to demonstrate migratory behavior in the chick, following chick migratory patterns and demonstrating a specific homing towards the chick mesonephros and gonad. These experiments not only provide a functional validation for in vitro-derived hPGCs that is complementary to molecular and epigenetic analysis, but also hint at the elements of hPGC development that are conserved throughout evolution. The gastruloid system is then used for further investigation into the hPGC niche. The power of this model system relies upon self-organization due to endogenous signaling in response to an exogenous BMP4 initiating signal, in a manner analogous to that found in the human embryo. We harness this power, using single cell image quantification and genetic tools including CRISPR-Cas9 to probe further into the signaling environment of the hPGC niche in the gastruloid model. We elucidate the role of each leg of the BMP4 – WNT – ACTIVIN/NODAL signaling cascade in development of this niche, which determines gastrulation events, in hPGC specification. These experiments not only demonstrate how BMP4 acts independently in addition to this cascade to directly specify hPGCs, but also how all three pathways work in harmony to generate self-organization of hPGCs within their gastruloid niche. By probing further into the ontogeny of hPGC specification, we find that upregulation of BLIMP1 alone, a canonical regulator of PGCs, is sufficient to induce later markers of hPGC fate, and surprisingly is also sufficient to downregulate SOX2 (a marker of epiblast and early ectodermal fate) and upregulate SOX17, which has been previously placed upstream of BLIMP1. Finally, we propose the marmoset as a good model of primate reproduction and embryogenesis, in an attempt to describe a non-human primate (NHP) system for validation of hPGC characteristics observed in vitro. We systematically investigate marmoset embryonic development in vivo using serial, high temporal and spatial resolution ultrasound imaging. We describe the morphological characteristics of implantation, gastrulation, neurulation, and organogenesis, as well as the curious marmoset phenotype of an elongated peri-gastrulation window, incorporating slowed embryonic growth and rapid extraembryonic development. In doing so, we generate an annotated ultrasound atlas of marmoset embryogenesis, and train models to identify developmental stages and predict fertilization ages from a single frame. In addition, we suggest that the extended peri-gastrulation window in the marmoset will provide a unique opportunity to perform in utero genetic editing, lineage tracing, and even allogenic transplantation to complement in vitro studies of hPGC development. This body of work provides a synthesis of culture techniques, genetic and molecular tools, and imaging systems that will provide a foundation for the exploration of not only human PGC development, but also hopefully a generalizable roadmap for translation between in vitro and in vivo studies early primate development
Public Financing for Low-cost Private Schools
Indonesia has a unique private schooling segment which contributes about 35% to the total number of schools in Indonesia. This segment mainly consists of Madrasah and Pondok Pesantren, which come under the Ministry of Religious Affairs (MoRA), while public schools come under Ministry of Education and Culture (MoEC). There is a much smaller and nascent sub-segment of private International schools, currently restricted to urban Java region. Madrasahs and Pesantren preexist public schools. They are both historic, culturally rooted and widely spread across the vast geography of Indonesia. Recognizing historical association of community-based educational institutions such as Madrasahs and Pesantren, the Education Law (Act 20/2003) of Indonesia states that the communities have the right to provide education, which is aligned with the social and cultural norms of the community
Web based nursing home information system : needs, benefits, and success in providing efficient care at long term care facilities
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on April 15, 2011).Vita.Thesis advisor: Mihail Popescu"December 2010"M.S. University of Missouri-Columbia 2010.Most of the nursing homes in the United States do not have clinical information systems at their facility due to which elderly people who reside in the facilities are not reaping the benefits that these systems are thought to have. Some Nursing homes that do have clinical information systems deployed are not primarily designed to support nursing care coordination. The purpose of this study is to explore the emerging need for Nursing Home Information Systems (NHIS) in long term care facilities and the promise they hold for increased efficiency, better accuracy, reduced cost, and improved outcomes. This study reports a pilot research done in development of a home-grown, web based, nursing home electronic health record (EHR) system for Aging in Place - TigerPlace; an independent housing with services facility, licensed assisted living facility, located in Columbia, Missouri. With Internet becoming an important topic in health care industry due to its capability for increased accessibility to information, a web based information system proves more beneficial to organizations. The emergence of World Wide Web technology constitutes one significant milestone on the road to efficient developments and deployment of clinically useful systems (Kittredge et al., 1996). Considering these benefits of web technology, this study first analyzes differences between traditional stand alone clinical systems and web based clinical systems. Further study concentrates on the need for TigerPlace facility to develop and implement a web based clinical information system, the process adopted towards developing the required system, its implementation and use at the facility, success of the system, and future enhancement possibilities for the system.Includes bibliographical references (p. 37-40)
Addition of 24‐hour heart rate variability parameters to the Cardiovascular Health Study stroke risk score and prediction of incident stroke: The Cardiovascular Health Study
Background Heart rate variability (HRV) characterizes cardiac autonomic functioning. The association of HRV with stroke is uncertain. We examined whether 24‐hour HRV added predictive value to the Cardiovascular Health Study clinical stroke risk score (CHS‐SCORE), previously developed at the baseline examination. Methods and Results N=884 stroke‐free CHS participants (age 75.3±4.6), with 24‐hour Holters adequate for HRV analysis at the 1994–1995 examination, had 68 strokes over ≤8 year follow‐up (median 7.3 [interquartile range 7.1–7.6] years). The value of adding HRV to the CHS‐SCORE was assessed with stepwise Cox regression analysis. The CHS‐SCORE predicted incident stroke (HR=1.06 per unit increment, P=0.005). Two HRV parameters, decreased coefficient of variance of NN intervals (CV%, P=0.031) and decreased power law slope (SLOPE, P=0.033) also entered the model, but these did not significantly improve the c‐statistic (P=0.47). In a secondary analysis, dichotomization of CV% (LOWCV% ≤12.8%) was found to maximally stratify higher‐risk participants after adjustment for CHS‐SCORE. Similarly, dichotomizing SLOPE (LOWSLOPE <−1.4) maximally stratified higher‐risk participants. When these HRV categories were combined (eg, HIGHCV% with HIGHSLOPE), the c‐statistic for the model with the CHS‐SCORE and combined HRV categories was 0.68, significantly higher than 0.61 for the CHS‐SCORE alone (P=0.02). Conclusions In this sample of older adults, 2 HRV parameters, CV% and power law slope, emerged as significantly associated with incident stroke when added to a validated clinical risk score. After each parameter was dichotomized based on its optimal cut point in this sample, their composite significantly improved prediction of incident stroke during ≤8‐year follow‐up. These findings will require validation in separate, larger cohorts. Keywords: autonomic nervous system, clinical stroke risk model, heart rate variability, prediction, predictors, risk prediction, risk stratification, strok
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