3,035 research outputs found

    Establishing a baseline for the study of maritime cultural heritage in the Gaza Strip

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    As a result of its geographic location, cultural diversity and historical trajectory, the Gaza strip is a key zone of scholarly enquiry and has a central role in the historical, social, political, economic, legislative and environmental discourses for the wider region. Existing historical knowledge of Gaza is dominated by combative narrative trends that emphasise the events of the 20th and 21st centuries and invoke archaeology extensively. In this context, cycles of material preservation and damage—often accompanying other forms of violence—have attracted the attention of academics and international media. Among the corollaries of this situation, is the destruction and marginalisation of vulnerable cultural heritage, particularly maritime cultural heritage, which is subjected to additional environmental, climatic, and anthropogenic pressures. As a means of countering the challenges on current field research in the region and to further assess the damage and threats faced by archaeological fabric, this paper combines data from coastal and archaeological research conducted in the Gaza Strip to create a benchmark for the study of its maritime archaeology. Additional information on the alteration of coastal landscape is deduced through the analysis of aerial photographs and satellite imagery. This study falls within the scope of the Maritime Endangered Archaeology in the Middle East and Africa Project (MarEA). MarEA aims to comprehensively document and assess vulnerable maritime archaeology (underwater, nearshore, coastal) and produce baseline information that can enhance existing infrastructure on archaeological monitoring and management.</p

    Limitations in Predicting Radiation-Induced Pharmaceutical Instability during Long-Duration Spaceflight

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    As human spaceflight seeks to expand beyond low-Earth orbit, NASA and its international partners face numerous challenges related to ensuring the safety of their astronauts, including the need to provide a safe and effective pharmacy for long-duration spaceflight. Historical missions have relied upon frequent resupply of onboard pharmaceuticals; as a result, there has been little study into the effects of long-term exposure of pharmaceuticals to the space environment. Of particular concern are the long-term effects of space radiation on drug stability, especially as missions venture away from the protective proximity of the Earth. Here we highlight the risk of space radiation to pharmaceuticals during exploration spaceflight, identifying the limitations of current understanding. We further seek to identify ways in which these limitations could be addressed through dedicated research efforts aimed towards the rapid development of an effective pharmacy for future spaceflight endeavors.Comment: in press, Nature Microgravit

    Value of Mendelian Laws of Segregation in Families: Data Quality Control, Imputation, and Beyond

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    When analyzing family data, we dream of perfectly informative data, even whole-genome sequences (WGSs) for all family members. Reality intervenes, and we find that next-generation sequencing (NGS) data have errors and are often too expensive or impossible to collect on everyone. The Genetic Analysis Workshop 18 working groups on quality control and dropping WGSs through families using a genome-wide association framework focused on finding, correcting, and using errors within the available sequence and family data, developing methods to infer and analyze missing sequence data among relatives, and testing for linkage and association with simulated blood pressure. We found that single-nucleotide polymorphisms, NGS data, and imputed data are generally concordant but that errors are particularly likely at rare variants, for homozygous genotypes, within regions with repeated sequences or structural variants, and within sequence data imputed from unrelated individuals. Admixture complicated identification of cryptic relatedness, but information from Mendelian transmission improved error detection and provided an estimate of the de novo mutation rate. Computationally, fast rule-based imputation was accurate but could not cover as many loci or subjects as more computationally demanding probability-based methods. Incorporating population-level data into pedigree-based imputation methods improved results. Observed data outperformed imputed data in association testing, but imputed data were also useful. We discuss the strengths and weaknesses of existing methods and suggest possible future directions, such as improving communication between data collectors and data analysts, establishing thresholds for and improving imputation quality, and incorporating error into imputation and analytical models

    Study of the island morphology at the early stages of Fe/Mo(110) MBE growth

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    We present theoretical study of morphology of Fe islands grown at Mo(110) surface in sub-monolayer MBE mode. We utilize atomistic SOS model with bond counting, and interactions of Fe adatom up to third nearest neighbors. We performed KMC simulations for different values of adatom interactions and varying temperatures. We have found that, while for the low temperature islands are fat fractals, for the temperature 500K islands have faceted rhombic-like shape. For the higher temperature, islands acquire a rounded shape. In order to evaluated qualitatively morphological changes, we measured averaged aspect ration of islands. We calculated dependence of the average aspect ratio on the temperature, and on the strength of interactions of an adatom with neighbors.Comment: 6 pages, 6 figures. Proceedings of 11-th Symposium on Surface Physics, Prague 200

    Strichartz estimates on Schwarzschild black hole backgrounds

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    We study dispersive properties for the wave equation in the Schwarzschild space-time. The first result we obtain is a local energy estimate. This is then used, following the spirit of earlier work of Metcalfe-Tataru, in order to establish global-in-time Strichartz estimates. A considerable part of the paper is devoted to a precise analysis of solutions near the trapping region, namely the photon sphere.Comment: 44 pages; typos fixed, minor modifications in several place

    Eleven years of monitoring the Seyfert 1 Mrk 335 with Swift: Characterizing the X-ray and UV/optical variability

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    The narrow-line Seyfert 1 galaxy (NLS1) Mrk 335 has been continuously monitored with Swift since May 2007 when it fell into a long-lasting, X-ray low-flux interval. Results from the nearly 11 years of monitoring are presented here. Structure functions are used to measure the UV-optical and X-ray power spectra. The X-ray structure function measured between 10-100 days is consistent with the flat, low-frequency part of the power spectrum measured previously in Mrk 335. The UV-optical structure functions of Mrk 335 are comparable with those of other Seyfert 1 galaxies and of Mrk 335 itself when it was in a normal bright state. There is no indication that the current X-ray low-flux state is attributed to changes in the accretion disc structure of Mrk 335. The characteristic timescales measured in the structure functions can be attributed to thermal (for the UV) and dynamic (for the optical) timescales in a standard accretion disc. The high-quality UVW2 (~1800 A in the source frame) structure function appears to have two breaks and two different slopes between 10-160 days. Correlations between the X-ray and other bands are not highly significant when considering the entire 11-year light curves, but more significant behaviour is present when considering segments of the light curves. A correlation between the X-ray and UVW2 in 2014 (Year-8) may be predominately caused by an giant X-ray flare that was interpreted as jet-like emission. In 2008 (Year-2), possible lags between the UVW2 emission and other UV-optical waveband may be consistent with reprocessing of X-ray or UV emission in the accretion disc.Comment: Figure 8b has been corrected. 12 pages. Accepted for publication in MNRA

    The Strauss conjecture on asymptotically flat space-times

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    By assuming a certain localized energy estimate, we prove the existence portion of the Strauss conjecture on asymptotically flat manifolds, possibly exterior to a compact domain, when the spatial dimension is 3 or 4. In particular, this result applies to the 3 and 4-dimensional Schwarzschild and Kerr (with small angular momentum) black hole backgrounds, long range asymptotically Euclidean spaces, and small time-dependent asymptotically flat perturbations of Minkowski space-time. We also permit lower order perturbations of the wave operator. The key estimates are a class of weighted Strichartz estimates, which are used near infinity where the metrics can be viewed as small perturbations of the Minkowski metric, and the assumed localized energy estimate, which is used in the remaining compact set.Comment: Final version, to appear in SIAM Journal on Mathematical Analysis. 17 page

    Identifying and Defining the Structures That Guide the Implementation of Participant Direction Programs and Support Program Participants: A Document Analysis

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    This is the author's accepted manuscript. The published version is available at http://dx.doi.org/10.1177/1044207313514112Participant direction (PD) programs offer the individual with a disability or his or her surrogate decision maker varying degrees of choice and control over the individual’s supports and services. We conducted a document analysis using grounded theory methods to identify the design elements of participant direction programs in long-term care. We analyzed 53 documents across multiple disabilities and funding sources. We identified and defined two major components of participant direction programs: policy and aid and assistance. The component of policy was represented by three structures that guide implementation of participant direction programs: (a) option to participant-direct, (b) participation stipulations, and (c) provider qualifications. The component of aid and assistance was represented by 11 structures that support program participants: (a) financial management services, (b) employer of record, (c) emergency back-up, (d) worker registry, (e) advice/counseling, (f) managerial assistance, (g) information dissemination products, (h) service quality monitoring, (i) service coordination, (j) participant training, and (k) provider training. Each structure was represented by one or more continua depicting the range of choice and control participants may have over the structure. The findings of this study have implications for improving the standardization of research on participant direction programs and the development of long-term care policy

    Identifying and defining the activities of participant direction programs: A document analysis

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    This is the author's accepted manuscript. The published version is available at http://dx.doi.org/10.1177/1044207313502538We analyzed the design of various U.S. programs of participant direction offering participants (individual with a disability or his or her surrogate decision-maker) some level of choice and control over the individual’s long-term care supports and services. We used grounded theory methods to conduct a document analysis of 53 documents published from 2004 through 2008 representing multiple disabilities and program funding sources. In our analysis, we identified three major components (planning, budgeting, and employing) over which participants had the opportunity to exercise choice and control and the activities associated with each. Activities were represented by one or more continua illustrating the range of participant choice and control over the indicator. The component of planning consisted of the activity of care plan development. The budgeting component included the activities of (a) development, (b) individualization, and (c) authority. The employing component included the activities of (a) identifying/selecting providers, (b) hiring/employing providers, (c) scheduling providers, (d) training providers, (e) managing/directing/supervising providers, (f) disciplining/dismissing providers, (g) keeping records, (h) managing payroll, (i) locating emergency back-up, and (j) monitoring service quality. The findings of this study have implications for improving policy, practice, and research in the field of long-term care

    Effects of communication and utility-based decision making in a simple model of evacuation

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    We present a simple cellular automaton based model of decision making during evacuation. Evacuees have to choose between two different exit routes, resulting in a strategic decision making problem. Agents take their decisions based on utility functions, these can be revised as the evacuation proceeds, leading to complex interaction between individuals and to jamming transitions. The model also includes the possibility to communicate and exchange information with distant agents, information received may affect the decision of agents. We show that under a wider range of evacuation scenarios performance of the model system as a whole is optimal at an intermediate fraction of evacuees with access to communication.Comment: 9 pages, 9 figure
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