340 research outputs found
Exploring the crystal structures of orientation maps in a scalable computational model of visual cortical maps
How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRR’s Rehabilitation Engineering Research Centers
Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a “total approach to rehabilitation”, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970’s, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program
Protein/DNA interactions in complex DNA topologies: expect the unexpected
DNA supercoiling results in compacted DNA structures that can bring distal sites into close proximity. It also changes the local structure of the DNA, which can in turn influence the way it is recognised by drugs, other nucleic acids and proteins. Here, we discuss how DNA supercoiling and the formation of complex DNA topologies can affect the thermodynamics of DNA recognition. We then speculate on the implications for transcriptional control and the three-dimensional organisation of the genetic material, using examples from our own simulations and from the literature. We introduce and discuss the concept of coupling between the multiple length-scales associated with hierarchical nuclear structural organisation through DNA supercoiling and topology
Design, Construction and Installation of the ATLAS Hadronic Barrel Scintillator-Tile Calorimeter
The scintillator tile hadronic calorimeter is a sampling calorimeter using steel as the absorber structure and scintillator as the active medium. The scintillator is located in "pockets" in the steel structure and the wavelength-shifting fibers are contained in channels running radially within the absorber to photomultiplier tubes which are located in the outer support girders of the calorimeter structure. In addition, to its role as a detector for high energy particles, the tile calorimeter provides the direct support of the liquid argon electromagnetic calorimeter in the barrel region, and the liquid argon electromagnetic and hadronic calorimeters in the endcap region. Through these, it indirectly supports the inner tracking system and beam pipe. The steel absorber, and in particular the support girders, provide the flux return for the solenoidal field from the central solenoid. Finally, the end surfaces of the barrel calorimeter are used to mount services, power supplies and readout crates for the inner tracking systems and the liquid argon barrel electromagnetic calorimeter
The Optical Instrumentation of the ATLAS Tile Calorimeter
The purpose of this Note is to describe the optical assembly procedure called here Optical Instrumentation and the quality tests conducted on the assembled units. Altogether, 65 Barrel (or LB) modules were constructed - including one spare - together with 129 Extended Barrel (EB) modules (including one spare). The LB modules were mechanically assembled at JINR (Dubna, Russia) and transported to CERN, where the optical instrumentation was performed with personnel contributed by several Institutes. The modules composing one of the two Extended Barrels (known as EBA) were mechanically assembled in the USA, and instrumented in two US locations (ANL, U. of Michigan), while the modules of the other Extended barrel (EBC) were assembled in Spain and instrumented at IFAE (Barcelona). Each of the EB modules includes a subassembly known as ITC that contributes to the hermeticity of the calorimeter; all ITCs were assembled at UTA (Texas), and mounted onto the module mechanical structures at the EB mechanical assembly locations.The Tile Calorimeter, covering the central region of the ATLAS experiment up to pseudorapidities of ±1.7, is a sampling device built with scintillating tiles that alternate with iron plates. The light is collected in wave-length shifting (WLS) fibers and is read out with photomultipliers. In the characteristic geometry of this calorimeter the tiles lie in planes perpendicular to the beams, resulting in a very simple and modular mechanical and optical layout. This paper focuses on the procedures applied in the optical instrumentation of the calorimeter, which involved the assembly of about 460,000 scintillator tiles and 550,000 WLS fibers. The outcome is a hadronic calorimeter that meets the ATLAS performance requirements, as shown in this paper
Search for Maximal Flavor Violating Scalars in Same-Charge Lepton Pairs in pp̅ Collisions at √s=1.96 TeV
Models of Maximal Flavor Violation (MxFV) in elementary particle physics may contain at least one new scalar SU doublet field that couples the first and third generation quarks () via a Lagrangian term . These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb collected by the CDF II detector in collisions at TeV are analyzed for evidence of the MxFV signature. For a neutral scalar with GeV/ and coupling , 11 signal events are expected over a background of events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling for GeV/.Models of maximal flavor violation (MxFV) in elementary particle physics may contain at least one new scalar SU(2) doublet field ΦFV=(η0,η+) that couples the first and third generation quarks (q1, q3) via a Lagrangian term LFV=ξ13ΦFVq1q3. These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb-1 collected by the Collider Dectector at Fermilab II detector in pp̅ collisions at √s=1.96 TeV are analyzed for evidence of the MxFV signature. For a neutral scalar η0 with mη0=200 GeV/c2 and coupling ξ13=1, ~11 signal events are expected over a background of 2.1±1.8 events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling ξ13 for mη0=180–300 GeV/c2.Peer reviewe
The Production and Qualification of Scintillator Tiles for the ATLAS Hadronic Calorimeter
The production of the scintillator tiles for the ATLAS Tile Calorimeter is presented. In addition to the manufacture and production, the properties of the tiles will be presented including light yield, uniformity and stability
Feasibility of an Environmental Scan-Based Approach to Collecting Information About Factors Impacting Cancer Genetics Services in Latin American Countries
OBJECTIVE: Clinical cancer genetics services are expanding globally, but national policy and health care systems influence availability and implementation. Understanding the environmental factors within a country is required to appropriately implement, adapt, and evaluate cancer genetics service delivery models. An environmental scan (ES) is an approach used in business, public health, health care and other sectors to collect information about an environment or system for strategic decision making and program planning. An ES has been previously used to assess cancer genetics clinic-level factors to inform quality improvement efforts in the United States. We assessed the feasibility of using an ES to collect information about factors that may influence cancer genetics service delivery in the outer-most socio-ecological model environmental levels (policy, national agencies, healthcare systems, cultural considerations) in three Latin American countries.
METHODS: Oncology and Genetics care team members at three participating sites used publicly available sources and personal experiences to complete a data collection form (DCF) that included questions about subtopics: laws and policies, relevant agencies and regulations, health care systems and insurance, and cultural considerations. Time to complete the DCF and DCF completeness were used to measure ES feasibility.
RESULTS: Participating sites completed the DCF in 3 months, and most questions (average, 87.0%) were answered. Questions in the cultural considerations subtopic had the fewest answers (average, 77.8%).
CONCLUSIONS: Overall, the ES was feasible and identified a lack of published literature related to cultural considerations impacting health care and genetics services uptake in Latin America. Environmental factors impact cancer genetics services, and identification of these factors will facilitate future collaborative research and genetics service delivery dissemination efforts
Displaced distal forearm fractures in children with an indication for reduction under general anesthesia should be percutaneously fixated
Surger
A Reaction-Diffusion Model to Capture Disparity Selectivity in Primary Visual Cortex
Decades of experimental studies are available on disparity selective cells in visual cortex of macaque and cat. Recently, local disparity map for iso-orientation sites for near-vertical edge preference is reported in area 18 of cat visual cortex. No experiment is yet reported on complete disparity map in V1. Disparity map for layer IV in V1 can provide insight into how disparity selective complex cell receptive field is organized from simple cell subunits. Though substantial amounts of experimental data on disparity selective cells is available, no model on receptive field development of such cells or disparity map development exists in literature. We model disparity selectivity in layer IV of cat V1 using a reaction-diffusion two-eye paradigm. In this model, the wiring between LGN and cortical layer IV is determined by resource an LGN cell has for supporting connections to cortical cells and competition for target space in layer IV. While competing for target space, the same type of LGN cells, irrespective of whether it belongs to left-eye-specific or right-eye-specific LGN layer, cooperate with each other while trying to push off the other type. Our model captures realistic 2D disparity selective simple cell receptive fields, their response properties and disparity map along with orientation and ocular dominance maps. There is lack of correlation between ocular dominance and disparity selectivity at the cell population level. At the map level, disparity selectivity topography is not random but weakly clustered for similar preferred disparities. This is similar to the experimental result reported for macaque. The details of weakly clustered disparity selectivity map in V1 indicate two types of complex cell receptive field organization
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