3,486 research outputs found
Dismount Threat Recognition through Automatic Pose Identification
The U.S. military has an increased need to rapidly identify nonconventional adversaries. Dismount detection systems are being developed to provide more information on and identify any potential threats. Current work in this area utilizes multispectral imagery to exploit the spectral properties of exposed skin and clothing. These methods are useful in the location and tracking of dismounts, but they do not directly discern a dismount\u27s level of threat. Analyzing the actions that precede hostile events yields information about how the event occurred and uncovers warning signs that are useful in the prediction and prevention of future events. A dismount\u27s posturing, or pose, indicates what he or she is about to do. Pose recognition and identification is a topic of study that can be utilized to discern this threat information. Pose recognition is the process of observing a scene through an imaging device, determining that a dismount is present, identifying the three dimensional (3D) position of the dismount\u27s joints, and evaluating what the current configuration of the joints means. This thesis explores the use of automatic pose recognition to identify threatening poses and postures by means of an artificial neural network. Data are collected utilizing the depth camera and joint estimation software of the Kinect for Xbox 360. A threat determination is made based on the pose identified by the network. Accuracy is measured both by the correct identification of the pose presented to the network, and proper threat discernment. The end network achieved approximately 81% accuracy for threat determination and 55% accuracy for pose identification with test sets of 26 unique poses. Overall, the high level of threat determination accuracy indicates that automatic pose recognition is a promising means of discerning whether a dismount is threatening or not
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Hearing through your eyes: neural basis of audiovisual cross-activation, revealed by transcranial alternating current stimulation
Some people experience auditory sensations when seeing visual flashes or movements. This prevalent synaesthesia-like ‘visual-evoked auditory response’ (vEAR) could result either from over-exuberant cross-activation between brain areas, and/or reduced inhibition of normally-occurring cross-activation. We have used transcranial alternating current stimulation (tACS) to test these theories. We applied tACS at 10Hz (alpha-band frequency) or 40Hz (gamma-band), bilaterally either to temporal or occipital sites, while measuring same/different discrimination of paired auditory (A) versus visual (V) 'Morse code' sequences. At debriefing, participants were classified as vEAR or non-vEAR depending on whether they reported 'hearing' the silent flashes.
In non-vEAR participants, temporal 10Hz tACS caused impairment of A performance, which correlated with improved V; conversely under occipital tACS, poorer V performance correlated with improved A. This reciprocal pattern suggests that sensory cortices are normally mutually inhibitory, and that alpha-frequency tACS may bias the balance of competition between them. vEAR participants showed no tACS effects, consistent with reduced inhibition, or enhanced cooperation between modalities. In addition, temporal 40Hz tACS impaired V performance, specifically in individuals who showed a performance advantage for V (relative to A). Gamma-frequency tACS may therefore modulate the ability of these individuals to benefit from recoding flashes into the auditory modality, possibly by disrupting cross-activation of auditory areas by visual stimulation.
Our results support both theories, suggesting that vEAR may depend on disinhibition of normally-occurring sensory cross-activation, which may be expressed more strongly in some individuals. Furthermore, endogenous alpha and gamma-frequency oscillations may function respectively to inhibit or promote this cross-activation
Measuring errors in single qubit rotations by pulsed electron paramagnetic resonance
The ability to measure and reduce systematic errors in single-qubit logic
gates is crucial when evaluating quantum computing implementations. We describe
pulsed electron paramagnetic resonance (EPR) sequences that can be used to
measure precisely even small systematic errors in rotations of
electron-spin-based qubits. Using these sequences we obtain values for errors
in rotation angle and axis for single-qubit rotations using a commercial EPR
spectrometer. We conclude that errors in qubit operations by pulsed EPR are not
limiting factors in the implementation of electron-spin based quantum
computers
Launching the New American College of Cardiology Research Network: Advancing High-Value Collaborative Research via “Innovative Networking”
The landscape of research and academic medicine is changing significantly, especially for the early career professional (ECP) cardiologist. The recent viewpoint paper in the Journal detailing the challenges of the early career academic cardiologist crystallizes this complex situation. Although there is a clear desire to conduct research among those surveyed, there are major obstacles to achieving a successful research career. Two of the major challenges identified by ECPs are a lack of collaborators and a lack of research mentors to assist in generating the needed data to produce a competitive grant application. As identified by the survey, a lack of collaborators and mentors negatively affects one’s ability to achieve viable research funding. The most vulnerable are cardiology fellows and junior investigators who are new to research, especially those with nontraditional research interests, who can struggle to find mentorship within their institutions. Those who are new to research must often rely on informal networking with speakers who are invited to give grand rounds within their institution or at national conferences. For a minority, these haphazard meetings may turn into successful long-term research collaborations, but for many, they unfortunately do not. Additionally, for ECPs already involved in research, there is inadequate access to new techniques and innovations as a direct result of the absence of comprehensive and collaborative research-oriented networks. For example, short-term access to expensive equipment or needed reagents may be the limiting factor in one’s research endeavors. Indeed, as highlighted in a recent Leadership Page in the Journal, there is little national investment in research networks, leading to many inefficiencies and unnecessary delays
High Fidelity Single Qubit Operations using Pulsed EPR
Systematic errors in spin rotation operations using simple RF pulses place
severe limitations on the usefulness of the pulsed magnetic resonance methods
in quantum computing applications. In particular, the fidelity of quantum logic
operations performed on electron spin qubits falls well below the threshold for
the application of quantum algorithms. Using three independent techniques, we
demonstrate the use of composite pulses to improve this fidelity by several
orders of magnitude. The observed high-fidelity operations are limited by pulse
phase errors, but nevertheless fall within the limits required for the
application of quantum error correction.Comment: 4 pages, 3 figures To appear in Phys. Rev. Let
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PD-1 Blockade in Chronically HIV-1-Infected Humanized Mice Suppresses Viral Loads
An estimated 34 million people are living with HIV worldwide (UNAIDS, 2012), with the number of infected persons rising every year. Increases in HIV prevalence have resulted not only from new infections, but also from increases in the survival of HIV-infected persons produced by effective anti-retroviral therapies. Augmentation of anti-viral immune responses may be able to further increase the survival of HIV-infected persons. One strategy to augment these responses is to reinvigorate exhausted anti-HIV immune cells present in chronically infected persons. The PD-1-PD-L1 pathway has been implicated in the exhaustion of virus-specific T cells during chronic HIV infection. Inhibition of PD-1 signaling using blocking anti-PD-1 antibodies has been shown to reduce simian immunodeficiency virus (SIV) loads in monkeys. We now show that PD-1 blockade can improve control of HIV replication in vivo in an animal model. BLT (Bone marrow-Liver-Thymus) humanized mice chronically infected with HIV-1 were treated with an anti-PD-1 antibody over a 10-day period. The PD-1 blockade resulted in a very significant 45-fold reduction in HIV viral loads in humanized mice with high CD8+ T cell expression of PD-1, compared to controls at 4 weeks post-treatment. The anti-PD-1 antibody treatment also resulted in a significant increase in CD8+ T cells. PD-1 blockade did not affect T cell expression of other inhibitory receptors co-expressed with PD-1, including CD244, CD160 and LAG-3, and did not appear to affect virus-specific humoral immune responses. These data demonstrate that inhibiting PD-1 signaling can reduce HIV viral loads in vivo in the humanized BLT mouse model, suggesting that blockade of the PD-1-PD-L1 pathway may have therapeutic potential in the treatment of patients already infected with the AIDS virus
Molecular identification and transmission studies of X-cell parasites from Atlantic cod Gadus morhua (Gadiformes: Gadidae) and the northern black flounder Pseudopleuronectes obscurus (Pleuronectiformes: Pleuronectidae)
Background: Epidermal pseudotumours from Hippoglossoides dubius and Acanthogobius flavimanus in Japan and gill lesions in Limanda limanda from the UK have been shown to be caused by phylogenetically related protozoan parasites, known collectively as X-cells. However, the phylogenetic position of the X-cell group is not well supported within any of the existing protozoan phyla and they are currently thought to be members of the Alveolata. Ultrastructural features of X-cells in fish pseudotumours are somewhat limited and no typical environmental stages, such as spores or flagellated cells, have been observed. The life cycles for these parasites have not been demonstrated and it remains unknown how transmission to a new host occurs. In the present study, pseudobranchial pseudotumours from Atlantic cod, Gadus morhua, in Iceland and epidermal pseudotumours from the northern black flounder, Pseudopleuronectes obscurus, in Japan were used in experimental transmission studies to establish whether direct transmission of the parasite is achievable. In addition, X-cells from Atlantic cod were sequenced to confirm whether they are phylogenetically related to other X-cells and epidermal pseudotumours from the northern black flounder were analysed to establish whether the same parasite is responsible for infecting different flatfish species in Japan. Results: Phylogenetic analyses of small subunit ribosomal DNA (SSU rDNA) sequence data from Atlantic cod X-cells show that they are a related parasite that occupies a basal position to the clade containing other X-cell parasites. The X-cell parasite causing epidermal pseudotumours in P. obscurus is the same parasite that causes pseudotumours in H. dubius. Direct, fish to fish, transmission of the X-cell parasites used in this study, via oral feeding or injection, was not achieved. Non-amoeboid X-cells are contained within discrete sac-like structures that are loosely attached to epidermal pseudotumours in flatfish; these X-cells are able to tolerate exposure to seawater. A sensitive nested PCR assay was developed for the sub clinical detection of both parasites and to assist in future life cycle studies. PCR revealed that the parasite in P. obscurus was detectable in non-pseudotumourous areas of fish that had pseudotumours present in other areas of the body. Conclusions: The inability to successfully transmit both parasites in this study suggests that either host detachment combined with a period of independent development or an alternate host is required to complete the life cycle for X-cell parasites. Phylogenetic analyses of SSU rDNA confirm a monophyletic grouping for all sequenced X-cell parasites, but do not robustly support their placement within any established protist phylum. Analysis of SSU rDNA from X-cells in Japanese flatfish reveals that the same parasite can infect more than one species of fish
Synchronizing Sequencing Software to a Live Drummer
Copyright 2013 Massachusetts Institute of Technology. MIT allows authors to archive published versions of their articles after an embargo period. The article is available at
Investment Opportunities for Livestock in the North Eastern Province of Kenya: A Synthesis of Existing Knowledge
Pastoralism is the dominant livelihood activity in the North Eastern Province (NEP) of Kenya. It is supplemented only by a limited amount of agriculture along the rivers. The province faces various developmental challenges including chronic poverty and food insecurity, low human capital and poor health standards, high vulnerability to climate change, poor infrastructure, insecurity and low crop and livestock productivity. This study synthesises existing knowledge and provides recommendations on livestock investments to increase incomes, create employment and reduce food insecurity in the province. It examines investment opportunities in livestock and presents scenarios that meet the objectives of Kenya’s 2030 vision. Four
scenarios are analysed. The first scenario consists of the business-as-usual case: a vision of the state of the livestock sector, and its contribution to NEP and national economy, if the current trajectory is maintained. The second scenario outlines a strategy that focuses on catering to domestic demand for livestock products. The third scenario focuses on feeding foreign demand for live animals, while the fourth scenario investigates the possibilities of a livestock sector driven by exports of processed livestock products. Also in these investment scenarios, the broad-based growth contribution to the economy is discussed. The analysis indicates that all three alternative scenarios have far better impacts on pastoralists’ income and employment than the ‘business-as-usual’ scenario. The second scenario is found to have the largest favourable impact. Besides creating jobs and income opportunities, it provides alternatives to meet the growing livestock product consumption spurred by population increase, rising incomes and urbanization in Kenya. However, there are several requirements for this scenario to work and yield the desired impact. The need for creating a favourable investment climate is discussed and specific roles of the public and private sectors are explained
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