2,833 research outputs found
Constraints on Dark Matter from Colliders
We show that colliders can impose strong constraints on models of dark
matter, in particular when the dark matter is light. We analyze models where
the dark matter is a fermion or scalar interacting with quarks and/or gluons
through an effective theory containing higher dimensional operators which
represent heavier states that have been integrated out of the effective field
theory. We determine bounds from existing Tevatron searches for monojets as
well as expected LHC reaches for a discovery. We find that colliders can
provide information which is complementary or in some cases even superior to
experiments searching for direct detection of dark matter through its
scattering with nuclei. In particular, both the Tevatron and the LHC can
outperform spin dependent searches by an order of magnitude or better over much
of parameter space, and if the dark matter couples mainly to gluons, the LHC
can place bounds superior to any spin independent search.Comment: 23 pages, 16 figure
Decoding information for grasping from the macaque dorsomedial visual stream
Neurodecoders have been developed by researchers mostly to control neuroprosthetic devices, but also to shed new light on neural functions. In this study, we show that signals representing grip configurations can be reliably decoded from neural data acquired from area V6A of the monkey medial posterior parietal cortex. Two Macaca fascicularis monkeys were trained to perform an instructed-delay reach-to-grasp task in the dark and in the light toward objects of different shapes. Population neural activity was extracted at various time intervals on vision of the objects, the delay before movement, and grasp execution. This activity was used to train and validate a Bayes classifier used for decoding objects and grip types. Recognition rates were well over chance level for all the epochs analyzed in this study. Furthermore, we detected slightly different decoding accuracies, depending on the task's visual condition. Generalization analysis was performed by training and testing the system during different time intervals. This analysis demonstrated that a change of code occurred during the course of the task. Our classifier was able to discriminate grasp types fairly well in advance with respect to grasping onset. This feature might be important when the timing is critical to send signals to external devices before the movement start. Our results suggest that the neural signals from the dorsomedial visual pathway can be a good substrate to feed neural prostheses for prehensile actions
Risk of Guillain-Barré syndrome after 2010–2011 influenza vaccination
Influenza vaccination has been implicated in Guillain Barré Syndrome (GBS) although the evidence for this link is controversial. A case–control study was conducted between October 2010 and May 2011 in seven Italian Regions to explore the relation between influenza vaccination and GBS. The study included 176 GBS incident cases aged ≥18 years from 86 neurological centers. Controls were selected among patients admitted for acute conditions to the Emergency Department of the same hospital as cases. Each control was matched to a case by sex, age, Region and admission date. Two different analyses were conducted: a matched case–control analysis and a self-controlled case series analysis (SCCS). Case–control analysis included 140 cases matched to 308 controls. The adjusted matched odds ratio (OR) for GBS occurrence within 6 weeks after influenza vaccination was 3.8 (95 % CI: 1.3, 10.5). A much stronger association with gastrointestinal infections (OR = 23.8; 95 % CI 7.3, 77.6) and influenza-like illness or upper respiratory tract infections (OR = 11.5; 95 % CI 5.6, 23.5) was highlighted. The SCCS analysis included all 176 GBS cases. Influenza vaccination was associated with GBS, with a relative risk of 2.1 (95 % CI 1.1, 3.9). According to these results the attributable risk in adults ranges from two to five GBS cases per 1,000,000 vaccinations
Evaluating the flood damage on dairy farms: a methodological proposal
The debate on climate change arose several concerns on the impacts of floods on agriculture and, consequently, on food security. At the same time, the European Floods Directive asks Members States to implement suitable measures to mitigate flood damage on economic activities, including farms. Still, while several analyses were developed to estimate potential flood damages on crops, a gap exists for livestock productions. The purpose of this study is to develop a conceptual model for the assessment of flood economic damages on dairy farms. Results propose a static and a dynamic model of farms recovery actions to re-establish the farming activity, which takes into account all farm components, as well as their interaction. Facing the destruction caused by floods, a first reaction of farmers could be closing the activity, with repercussion on this well-being as well as on farm workers\u2019, and on the economy of rural areas. From this perspective, this study wants to provide a first methodological pathway to support farmers in restoring their activity
Association between Outdoor Air Pollution and Childhood Leukemia: A Systematic Review and Dose-Response Meta-Analysis.
BackgroundA causal link between outdoor air pollution and childhood leukemia has been proposed, but some older studies suffer from methodological drawbacks. To the best of our knowledge, no systematic reviews have summarized the most recently published evidence and no analyses have examined the dose-response relation.ObjectiveWe investigated the extent to which outdoor air pollution, especially as resulting from traffic-related contaminants, affects the risk of childhood leukemia.MethodsWe searched all case-control and cohort studies that have investigated the risk of childhood leukemia in relation to exposure either to motorized traffic and related contaminants, based on various traffic-related metrics (number of vehicles in the closest roads, road density, and distance from major roads), or to measured or modeled levels of air contaminants such as benzene, nitrogen dioxide, 1,3-butadiene, and particulate matter. We carried out a meta-analysis of all eligible studies, including nine studies published since the last systematic review and, when possible, we fit a dose-response curve using a restricted cubic spline regression model.ResultsWe found 29 studies eligible to be included in our review. In the dose-response analysis, we found little association between disease risk and traffic indicators near the child's residence for most of the exposure range, with an indication of a possible excess risk only at the highest levels. In contrast, benzene exposure was positively and approximately linearly associated with risk of childhood leukemia, particularly for acute myeloid leukemia, among children under 6 y of age, and when exposure assessment at the time of diagnosis was used. Exposure to nitrogen dioxide showed little association with leukemia risk except at the highest levels.DiscussionOverall, the epidemiologic literature appears to support an association between benzene and childhood leukemia risk, with no indication of any threshold effect. A role for other measured and unmeasured pollutants from motorized traffic is also possible. https://doi.org/10.1289/EHP4381
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