Opportunistic Collaborative Beamforming with One-Bit Feedback

An energy-efficient opportunistic collaborative beamformer with one-bit feedback is proposed for ad hoc sensor networks over Rayleigh fading channels. In contrast to conventional collaborative beamforming schemes in which each source node uses channel state information to correct its local carrier offset and channel phase, the proposed beamforming scheme opportunistically selects a subset of source nodes whose received signals combine in a quasi-coherent manner at the intended receiver. No local phase-precompensation is performed by the nodes in the opportunistic collaborative beamformer. As a result, each node requires only one-bit of feedback from the destination in order to determine if it should or shouldn't participate in the collaborative beamformer. Theoretical analysis shows that the received signal power obtained with the proposed beamforming scheme scales linearly with the number of available source nodes. Since the the optimal node selection rule requires an exhaustive search over all possible subsets of source nodes, two low-complexity selection algorithms are developed. Simulation results confirm the effectiveness of opportunistic collaborative beamforming with the low-complexity selection algorithms.Comment: Proceedings of the Ninth IEEE Workshop on Signal Processing Advances in Wireless Communications, Recife, Brazil, July 6-9, 200

A case of Penicillium marneffei osteomyelitis involving the axial skeleton

Fungal infection of bone by Penicillium marneffei is rare. We report on a case of Penicillium marneffei infection in a Filipino woman, which involved multiple soft-tissue abscesses and infection of the axial skeleton. Early diagnosis and treatment of this potentially reversible disease is emphasised. Such an approach is essential to prevent bony destruction from becoming too advanced and, more importantly, to prevent any damage to the spinal cord from occurring.published_or_final_versio

Thin accretion disks onto brane world black holes

The braneworld description of our universe entails a large extra dimension and a fundamental scale of gravity that might be lower by several orders of magnitude as compared to the Planck scale. An interesting consequence of the braneworld scenario is in the nature of the vacuum solutions of the brane gravitational field equations, with properties quite distinct as compared to the standard black hole solutions of general relativity. One possibility of observationally discriminating between different types of black holes is the study of the emission properties of the accretion disks. In the present paper we obtain the energy flux, the emission spectrum and accretion efficiency from the accretion disks around several classes of static and rotating brane world black holes, and we compare them to the general relativistic case. Particular signatures can appear in the electromagnetic spectrum, thus leading to the possibility of directly testing extra-dimensional physical models by using astrophysical observations of the emission spectra from accretion disks.Comment: 37 pages, 14 figures, accepted for publication in PR

Factors affecting communication in emergency departments: doctors and nurses’ perceptions of communication in a trilingual ED in Hong Kong

© 2015, Pun et al. Background: This study investigates clinicians’ views of clinician-patient and clinician-clinician communication, including key factors that prevent clinicians from achieving successful communication in a large, high-pressured trilingual Emergency Department (ED) in Hong Kong. Methods: Researchers interviewed 28 doctors and nurses in the ED. The research employed a qualitative ethnographic approach. The interviews were audio-recorded, transcribed, translated into English and coded using the Nvivo software. The researchers examined issues in both clinician-patient and clinician-clinician communication. Through thematic analyses, they identified the factors that impede communication most significantly, as well as the relationship between these factors. This research highlights the significant communication issues and patterns in Hong Kong EDs. Results: The clinician interviews revealed that communication in EDs is complex, nuanced and fragile. The data revealed three types of communication issues: (1) the experiential parameter (i.e. processes and procedures), (2) the interpersonal parameter (i.e. clinicians’ engagements with patients and other clinicians) and (3) contextual factors (i.e. time pressures, etc.). Within each of these areas, the specific problems were the following: compromises in knowledge transfer at key points of transition (e.g. triage, handover), inconsistencies in medical record keeping, serious pressures on clinicians (e.g. poor clinician-patient ratio and long working hours for clinicians) and a lack of focus on interpersonal skills. Conclusions: These communication problems (experiential, interpersonal and contextual) are intertwined, creating a complex yet weak communication structure that compromises patient safety, as well as patient and clinician satisfaction. The researchers argue that hospitals should develop and implement best-practice policies and educational programmes for clinicians that focus on the following: (1) understanding the primary causes of communication problems in EDs, (2) accepting the tenets and practices of patient-centred care, (3) establishing clear and consistent knowledge transfer procedures and (4) lowering the patient-to-clinician ratio in order to create the conditions that foster successful communication. The research provides a model for future research on the relationship between communication and the quality and safety of the patient safety

"TOF2H": A precision toolbox for rapid, high density/high coverage hydrogen-deuterium exchange mass spectrometry via an LC-MALDI approach, covering the data pipeline from spectral acquisition to HDX rate analysis

<p>Abstract</p> <p>Background</p> <p>Protein-amide proton hydrogen-deuterium exchange (HDX) is used to investigate protein conformation, conformational changes and surface binding sites for other molecules. To our knowledge, software tools to automate data processing and analysis from sample fractionating (LC-MALDI) mass-spectrometry-based HDX workflows are not publicly available.</p> <p>Results</p> <p>An integrated data pipeline (Solvent Explorer/TOF2H) has been developed for the processing of LC-MALDI-derived HDX data. Based on an experiment-wide template, and taking an <it>ab initio </it>approach to chromatographic and spectral peak finding, initial data processing is based on accurate mass-matching to fully deisotoped peaklists accommodating, in MS/MS-confirmed peptide library searches, ambiguous mass-hits to non-target proteins. Isotope-shift re-interrogation of library search results allows quick assessment of the extent of deuteration from peaklist data alone. During raw spectrum editing, each spectral segment is validated in real time, consistent with the manageable spectral numbers resulting from LC-MALDI experiments. A semi-automated spectral-segment editor includes a semi-automated or automated assessment of the quality of all spectral segments as they are pooled across an XIC peak for summing, centroid mass determination, building of rates plots on-the-fly, and automated back exchange correction. The resulting deuterium uptake rates plots from various experiments can be averaged, subtracted, re-scaled, error-barred, and/or scatter-plotted from individual spectral segment centroids, compared to solvent exposure and hydrogen bonding predictions and receive a color suggestion for 3D visualization. This software lends itself to a "divorced" HDX approach in which MS/MS-confirmed peptide libraries are built via nano or standard ESI without source modification, and HDX is performed via LC-MALDI using a standard MALDI-TOF. The complete TOF2H package includes additional (eg LC analysis) modules.</p> <p>Conclusion</p> <p>"TOF2H" provides a comprehensive HDX data analysis package that has accelerated the processing of LC-MALDI-based HDX data in the authors' lab from weeks to hours. It runs in a standard MS Windows (XP or Vista) environment, and can be downloaded <url>http://tof2h.bio.uci.edu</url> or obtained from the authors at no cost.</p

Analysing the Effect of Substrate Properties on Building Envelope Thermal Performance in Various Climates

Existing regulations on the thermal efficiency of building envelope assemblies are based on the steady state thermal properties of substrate materials. Heat transfer mechanisms of passive heat curbing methods such as phase change materials and cool materials, which are dynamic in nature, are currently not being accounted for. The effectiveness of thermo-physical and solar radiation properties of building materials (i.e., solid homogeneous layers without air gap) in reducing the heat gain into a building in a hot climate could be well understood with the equivalent thermal resistance (Req) concept. A simple and easy-to-use mathematical derivation (i.e., to estimate the instantaneous heat flux across an envelope assembly) is proposed in this paper to understand the mechanism of equivalent R-value (i.e., reciprocal of thermal transmittance, U-value) due to solar radiation properties of passive substrate materials. The model is validated against field experiments carried out at two apartment units of a residential building. The Req due to high outer surface solar radiation properties (i.e., by applying a cool coating) is dynamic as it varies with the weather conditions. The effect of a substrate material&rsquo;s solar radiation and thermo-physical properties on the overall roof thermal performance is investigated using the Req model for four cooling dominated climates around the globe, having different diurnal conditions and sky temperatures. Increasing the outer surface&rsquo;s solar reflectance (from 10 to 80) reduces net heat gain through the flat roof during both daytime and nighttime. In contrast, adding only thermal resistance (from 5 mm to 75 mm thick polyurethane) or volumetric heat capacity (by adding 5 mm thick phase change material) to the building envelope brings down heat gain during the day, but not in the night. Thermal insulation is found to be the second effective property, followed by thermal mass irrespective of different diurnal conditions and sky temperatures across the climates

Helping to distinguish primary from secondary transfer events for trace DNA.

DNA is routinely recovered in criminal investigations. The sensitivity of laboratory equipment and DNA profiling kits means that it is possible to generate DNA profiles from very small amounts of cellular material. As a consequence, it has been shown that DNA we detect may not have arisen from a direct contact with an item, but rather through one or more intermediaries. Naturally the questions arising in court, particularly when considering trace DNA, are of how DNA may have come to be on an item. While scientists cannot directly answer this question, forensic biological results can help in discriminating between alleged activities. Much experimental research has been published showing the transfer and persistence of DNA under varying conditions, but as of yet the results of these studies have not been combined to deal with broad questions about transfer mechanisms. In this work we use published data and Bayesian networks to develop a statistical logical framework by which questions of transfer mechanism can be approached probabilistically. We also identify a number of areas where further work could be carried out in order to improve our knowledge base when helping to address questions about transfer mechanisms. Finally, we apply the constructed Bayesian network to ground truth known data to determine if, with current knowledge, there is any power in DNA quantities to distinguish primary and secondary transfer events

The Ultraluminous X-ray Sources near the Center of M82

We report the identification of a recurrent ultraluminous X-ray source (ULX), a highly absorbed X-ray source (possibly a background AGN), and a young supernova remnant near the center of the starburst galaxy M82. From a series of Chandra observations taken from 1999 to 2005, we found that the transient ULX first appeared in 1999 October. The source turned off in 2000 January, but later reappeared and has been active since then. The X-ray luminosity of this source varies from below the detection level (~2.5e38 erg/s) to its active state in between ~7e39 erg/s and 1.3e40 erg/s (in the 0.5-10 keV energy band) and shows unusual spectral changes. The X-ray spectra of some Chandra observations are best fitted with an absorbed power-law model with photon index ranging from 1.3 to 1.7. These spectra are similar to those of Galactic black hole binary candidates seen in the low/hard state except that a very hard spectrum was seen in one of the observations. By comparing with near infrared images taken with the Hubble Space Telescope, the ULX is found to be located within a young star cluster. Radio imaging indicates that it is associated with a H II region. We suggest that the ULX is likely to be a > 100 solar mass intermediate-mass black hole in the low/hard state. In addition to the transient ULX, we also found a highly absorbed hard X-ray source which is likely to be an AGN and an ultraluminous X-ray emitting young supernova remnant which may be related to a 100-year old gamma-ray burst event, within 2 arcsec of the transient ULX.Comment: 9 pages, 8 figures. Accepted for publication in Ap

Communication in Hong Kong accident and emergency departments: The clinicians’ perspectives

© The Author(s) 2015. In this article, we report findings from the first qualitatively driven study of patient–clinician communication in Hong Kong Accident and Emergency Departments (AEDs). In light of the Hong Kong Hospital Authority’s policy emphasis on patientcentered care and communication in the public hospitals it oversees, we analyze clinicians’ perceptions of the role and relevance of patient-centered communication strategies in emergency care. Although aware of the importance of effective communication in emergency care, participants discussed how this was frequently jeopardized by chronic understaffing, patient loads, and time pressures. This was raised in relation to the absence of spoken interdisciplinary handovers, the tendency to downgrade interpersonal communication with patients, and the decline in staff attendance at communication training courses. Participants’ frequent descriptions of patient-centered communication as dispensable from, and timeburdensome in, AEDs highlight a discrepancy between the stated Hong Kong Hospital Authority policy of patient-centered care and the reality of contemporary Hong Kong emergency practice