23 research outputs found

    On the Origin of Light Dark Matter Species

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    TeV-mass dark matter charged under a new GeV-scale gauge force can explain electronic cosmic-ray anomalies. We propose that the CoGeNT and DAMA direct detection experiments are observing scattering of light stable states -- "GeV-Matter" -- that are charged under this force and constitute a small fraction of the dark matter halo. Dark higgsinos in a supersymmetric dark sector are natural candidates for GeV-Matter that scatter off protons with a universal cross-section of 5 x 10^{-38} cm^2 and can naturally be split by 10-30 keV so that their dominant interaction with protons is down-scattering. As an example, down-scattering of an O(5) GeV dark higgsino can simultaneously explain the spectra observed by both CoGeNT and DAMA. The event rates in these experiments correspond to a GeV-Matter abundance of 0.2-1% of the halo mass density. This abundance can arise directly from thermal freeze-out at weak coupling, or from the late decay of an unstable TeV-scale WIMP. Our proposal can be tested by searches for exotics in the BaBar and Belle datasets.Comment: 31 text pages, 4 figures, revision includes corrected Germanium quenching factor and clarified text in Sec.

    Genetics of randomly bred cats support the cradle of cat domestication being in the Near East

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    Cat domestication likely initiated as a symbiotic relationship between wildcats (Felis silvestris subspecies) and the peoples of developing agrarian societies in the Fertile Crescent. As humans transitioned from hunter-gatherers to farmers ~12,000 years ago, bold wildcats likely capitalized on increased prey density (i.e., rodents). Humans benefited from the cats’ predation on these vermin. To refine the site(s) of cat domestication, over 1000 random-bred cats of primarily Eurasian descent were genotyped for single-nucleotide variants and short tandem repeats. The overall cat population structure suggested a single worldwide population with significant isolation by the distance of peripheral subpopulations. The cat population heterozygosity decreased as genetic distance from the proposed cat progenitor’s (F.s. lybica) natural habitat increased. Domestic cat origins are focused in the eastern Mediterranean Basin, spreading to nearby islands, and southernly via the Levantine coast into the Nile Valley. Cat population diversity supports the migration patterns of humans and other symbiotic species

    Simplified Models for LHC New Physics Searches

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    This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the "Topologies for Early LHC Searches" workshop, held at SLAC in September of 2010, the purpose of which was to develop a set of representative models that can be used to cover all relevant phase space in experimental searches. Particular emphasis is placed on searches relevant for the first ~50-500 pb-1 of data and those motivated by supersymmetric models. This note largely summarizes material posted at http://lhcnewphysics.org/, which includes simplified model definitions, Monte Carlo material, and supporting contacts within the theory community. We also comment on future developments that may be useful as more data is gathered and analyzed by the experiments.Comment: 40 pages, 2 figures. This document is the official summary of results from "Topologies for Early LHC Searches" workshop (SLAC, September 2010). Supplementary material can be found at http://lhcnewphysics.or

    Key factors for establishing and sustaining a successful palliative radiation oncology program: a survey of the Society for Palliative Radiation Oncology

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    Background: Dedicated palliative radiation oncology programs (PROPs) within radiation oncology (RO) practices have been shown to improve quality and decrease costs of radiation therapy (RT) in advanced cancer patients. Despite this, relatively few PROPs currently exist, highlighting an unmet need to understand characteristics of the few existing PROPs and the potential barriers and facilitators that exist in starting and maintaining a successful PROP. We sought to assess the attributes of existing PROPs, the facilitators and barriers to establishing these programs, and the resources needed to create and maintain a successful program. Methods: A 15-item online survey was sent to 157 members of the Society of Palliative Radiation Oncology (SPRO) in July 2019. Results: Of the 157 members, 48 (31%) responded. Most practiced in an academic center (71% at main center and 15% at satellite) and 75% were from a larger group practice (≄ 6 physicians). Most (89%) believed the development and growth of a dedicated PROPs was either important (50%) or most important (39%) to the field of RO. Only 36% of respondents had a PROP, 38% wanted to establish one, and 13% were currently developing one. Of those with PROPs (N=16), 75% perceived an increase in the number of referrals for palliative RT since starting the program. A majority had an ability to refer to an outside palliative care specialist (64%), an outpatient RO service (53%), and specialized clinical processes for managing palliative radiotherapy patients (53%), with 41% having an inpatient RO consult service. Resources considered most essential were access to specialist-level palliative care, advanced practice provider support, a radiation oncologist with an interest in palliative care, having an outpatient palliative RO clinic, an emphasis on administering short radiation courses, and opportunities for educational development. Of those with a PROP or those who have tried to start one, the greatest perceived barriers to initiating a PROP were committed resources (83%), blocked out clinical time (61%), challenges coordinating management of patients (61%), and support from leaders/colleagues (61%). Perceived barriers to sustaining a PROP were similar. For those without a PROP, the perceived most important resources for starting one included access to palliative care specialist by referral (83%), published guidelines with best practices (80%), educational materials for referring physicians and patients (80%), educational sessions for clinical staff (83%), and standardized clinical pathways (80%). Conclusions: PROPs are not widespread, exist mainly within academic centers, are outpatient, have access to palliative care specialists by referral, and have specialized clinical processes for palliative radiation patients. Lack of committed resources was the single most important perceived barrier for initiating or maintaining a PROP. Best practice guidelines, educational resources, access to palliative care specialists and standardized pathways are most important for those who wish to develop a PROP. These insights can inform discussions and help align resources to develop, grow, and maintain a successful PROP

    “A reference genome assembly and adaptive trait analysis of Castanea mollissima ‘Vanuxem,’ a source of resistance to chestnut blight in restoration breeding”

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    Forest tree species are increasingly subject to severe mortalities from exotic pests, pathogens, and invasive organisms, accelerated by climate change. Such forest health issues are threatening multiple species and ecosystem sustainability globally. One of the most extreme examples of forest ecosystem disruption is the extirpation of the American chestnut (Castanea dentata) caused by the introduction of chestnut blight and root rot pathogens from Asia. Asian species of chestnut are being employed as donors of disease resistance genes to restore native chestnut species in North America and Europe. To aid in the restoration of threatened chestnut species, we present the assembly of a reference genome for Chinese chestnut (C. mollissima) "Vanuxem," one of the donors of disease resistance for American chestnut restoration. From the de novo assembly of the complete genome (725.2 Mb in 14,110 contigs), over half of the sequences have been anchored to the 12 genetic linkage groups. The anchoring is validated by genetic maps and in situ hybridization to chromosomes. We demonstrate the value of the genome as a platform for research and species restoration, including signatures of selection differentiating American chestnut from Chinese chestnut to identify important candidate genes for disease resistance, comparisons of genome organization with other woody species, and a genome-wide examination of progress in backcross breeding for blight resistance. This reference assembly should prove of great value in the understanding, improvement, and restoration of chestnut species

    Rdh12 Activity and Effects on Retinoid Processing in the Murine Retina*

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    RDH12 mutations are responsible for early-onset autosomal recessive retinal dystrophy, which results in profound retinal pathology and severe visual handicap in patients. To investigate the function of RDH12 within the network of retinoid dehydrogenases/reductases (RDHs) present in retina, we studied the retinal phenotype of Rdh12-deficient mice. In vivo rates of all-trans-retinal reduction and 11-cis-retinal formation during recovery from bleaching were similar in Rdh12-deficient and wild-type mice matched for an Rpe65 polymorphism that impacts visual cycle efficiency. However, retinal homogenates from Rdh12-deficient mice exhibited markedly decreased capacity to reduce exogenous retinaldehydes in vitro. Furthermore, in vivo levels of the bisretinoid compound diretinoid-pyridinium-ethanolamine (A2E) were increased in Rdh12-deficient mice of various genetic backgrounds. Conversely, in vivo levels of retinoic acid and total retinol were significantly decreased. Rdh12 transcript levels in wild-type mice homozygous for the Rpe65-Leu450 polymorphism were greater than in Rpe65-Met450 mice and increased during postnatal development in wild-type mice and Nrl-deficient mice having an all-cone retina. Rdh12-deficient mice did not exhibit increased retinal degeneration relative to wild-type mice at advanced ages, when bred on the light-sensitive BALB/c background, or when heterozygous for a null allele of superoxide dismutase 2 (Sod2+/−). Our findings suggest that a critical function of RDH12 is the reduction of all-trans-retinal that exceeds the reductive capacity of the photoreceptor outer segments
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