1,436 research outputs found

    Discovery of the VHE gamma-ray source HESS J1641-463

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    A new TeV source, HESS J1641-463, has been serendipitously discovered in the Galactic plane by the High Energy Stereoscopic System (H.E.S.S.) at a significance level of 8.6 standard deviations. The observations of HESS J1641-463 were performed between 2004 and 2011 and the source has a moderate flux level of 1.7% of the Crab Nebula flux at E > 1 TeV. HESS J1641-463 has a rather hard photon index of 1.99 +- 0.13_stat +- 0.20_sys. HESS J1641-463 is positionally coincident with the radio supernova remnant SNR G338.5+0.1, but no clear X-ray counterpart has been found in archival Chandra observations of the region. Different possible VHE production scenarios will be discussed in this contribution.Comment: 5 pages, 5 figures, 2012 Fermi Symposium proceedings - eConf C12102

    Advances in targeted Alpha therapy for prostate cancer

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    BACKGROUND: Amongst therapeutic radiopharmaceuticals, targeted alpha therapy (TαT) can deliver potent and local radiation selectively to cancer cells as well as the tumor microenvironment and thereby control cancer while minimizing toxicity. DESIGN: In this review, we discuss the history, progress, and future potential of TαT in the treatment of prostate cancer, including dosimetry-individualized treatment planning, combinations with small-molecule therapies, and conjugation to molecules directed against antigens expressed by prostate cancer cells, such as prostate-specific membrane antigen (PSMA) or components of the tumor microenvironment. RESULTS: A clinical proof of concept that TαT is efficacious in treating bone-metastatic castration-resistant prostate cancer has been demonstrated by radium-223 via improved overall survival and long-term safety/tolerability in the phase III ALSYMPCA trial. Dosimetry calculation and pharmacokinetic measurements of TαT provide the potential for optimization and individualized treatment planning for a precision medicine-based cancer management paradigm. The ability to combine TαTs with other agents, including chemotherapy, androgen receptor (AR)-targeting agents, DNA repair inhibitors, and immuno-oncology agents, is under investigation. Currently, TαTs that specifically target prostate cancer cells expressing PSMA represents a promising therapeutic approach. Both PSMA-targeted actinium-225 and thorium-227 conjugates are under investigation. CONCLUSIONS: The described clinical benefit, safety and tolerability of radium-223 and the recent progress in TαT trial development suggest that TαT occupies an important new role in prostate cancer treatment. Ongoing studies with newer dosimetry methods, PSMA targeting, and novel approaches to combination therapies should expand the utility of TαT in prostate cancer treatment

    Fairtrade and Labour Markets in Ethiopia and Uganda

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    Drawing on four years of fieldwork in Ethiopia and Uganda, this paper addresses gaps in knowledge about the mechanisms linking agricultural exports with poverty reduction, the functioning of rural labour markets, and the relevance to the lives of the poorest people of Fairtrade. Statistical analysis of survey evidence, complemented by qualitative research, highlights the relatively poor payment and non-pay working conditions of those employed in research sites dominated by Fairtrade producer organizations. We conclude that Fairtrade is not an effective way to improve the welfare of the poorest rural people

    Neural phase locking predicts BOLD response in human auditory cortex

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    Natural environments elicit both phase-locked and non-phase-locked neural responses to the stimulus in the brain. The interpretation of the BOLD signal to date has been based on an association of the non-phase-locked power of high-frequency local field potentials (LFPs), or the related spiking activity in single neurons or groups of neurons. Previous studies have not examined the prediction of the BOLD signal by phase-locked responses. We examined the relationship between the BOLD response and LFPs in the same nine human subjects from multiple corresponding points in the auditory cortex, using amplitude modulated pure tone stimuli of a duration to allow an analysis of phase locking of the sustained time period without contamination from the onset response. The results demonstrate that both phase locking at the modulation frequency and its harmonics, and the oscillatory power in gamma/high-gamma bands are required to predict the BOLD response. Biophysical models of BOLD signal generation in auditory cortex therefore require revision and the incorporation of both phase locking to rhythmic sensory stimuli and power changes in the ensemble neural activity

    Orthogonal Light-Dependent Membrane Adhesion Induces Social Self-Sorting and Member-Specific DNA Communication in Synthetic Cell Communities

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    Developing orthogonal chemical communication pathways in diverse synthetic cell communities is a considerable challenge due to the increased crosstalk and interference associated with large numbers of different types of sender-receiver pairs. Herein, the authors control which sender-receiver pairs communicate in a three-membered community of synthetic cells through red and blue light illumination. Semipermeable protein-polymer-based synthetic cells (proteinosomes) with complementary membrane-attached protein adhesion communicate through single-stranded DNA oligomers and synergistically process biochemical information within a community consisting of one sender and two different receiver populations. Different pairs of red and blue light-responsive protein-protein interactions act as membrane adhesion mediators between the sender and receivers such that they self-assemble and socially self-sort into different multicellular structures under red and blue light. Consequently, distinct sender-receiver pairs come into the signaling range depending on the light illumination and are able to communicate specifically without activation of the other receiver population. Overall, this work shows how photoswitchable membrane adhesion gives rise to different self-sorting protocell patterns that mediate member-specific DNA-based communication in ternary populations of synthetic cells and provides a step towards the design of orthogonal chemical communication networks in diverse communities of synthetic cells

    Validación del monitor de medición de la grasa corporal por impedancia bioeléctrica OMRON BF 300

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    ObjetivosValorar la precisión del monitor de grasa corporal por impedancia bioeléctrica OMRON BF 300 y validar su medición del porcentaje de grasa corporal (%GC) frente a la ecuación de Siri. Diseño. Estudio descriptivo, transversal.EmplazamientoAtención primaria. Centros de Salud Coronel de Palma y San Fernando, Móstoles.ParticipantesEn la valoración de la precisión del monitor participaron 88 personas y 91 en la validación.Mediciones y resultados principalesLas determinaciones de %GC se realizaron por triplicado, anotándose la media. La precisión se evaluó mediante el coeficiente de correlación intraclase (CCI) y el coeficiente de variación (CV). La validez, mediante el error técnico, el CCI y el método de Bland-Altman. En la ecuación de Siri la densidad corporal se calculó con la ecuación de Durnin-Womersley. Precisión: el CCI fue de 0,999 y el CV de 0,4 ± 0,03. Validación: la diferencia de %GC monitor (26,6 ± 9,1%) – ecuación de Siri (27,8 ± 8,2%) fue de –1,27% (p < 0,01; IC del 95%, –1,97 a –0,57), el error técnico del monitor del 2,2% y el CCI de 0,956 (IC del 95%, 0,9335–0,9710), situándose un 80,2% de las diferencias monitor – ecuación por debajo del 5%, con un intervalo de concordancia por el método de Bland-Altman de +5,45 a –7,99%.ConclusionesEl monitor OMRON BF 300 satisface los criterios de precisión (CCI > 0,95 y CV bajo) y validación (error técnico excelente, CCI > 0,75 y diferencias clínicamente aceptables) y supone una alternativa válida a los pliegues cutáneos en la valoración nutricional del paciente.ObjectivesTo assess the accuracy of the OMRON BF 300 body fat monitor using bioelectric impedance and to validate its measurement of body fat percentage (BF%) against the Siri equation.DesignCross-sectional descriptive study.SettingPrimary care. Coronel de Palma and San Fernando Health Centres, Móstoles.Participants88 people took part in the assessment of the accuracy of the monitor, and 91 in the validation.Measurements and main resultsThe BF% were recorded in triplicate, with the mean being the figure noted. Precision was evaluated through the intra-class correlation coefficient (ICC) and the coefficient of variation (CV); validity, through technical error, the ICC and the Bland-Altman method. In the Siri equation, body density was calculated through the Durnin-Womersley equation. Precision: ICC was 0.999 and CV 0.4 ± 0.03. Validation: the difference between the BF% monitor (26.6 ± 9.1%) and the Siri equation (27.8 ± 8.2%) was –1.27% (p < 0.01; 95% CI –1.97 to –0.57); the technical error of the monitor was 2.2% and of the ICC 0.956 (95% CI, 0.9335–0.9710). Thus, 80.2% of the monitor-equation differences were below 5%, with a concordance interval under the Bland-Altman method of +5.45 to –7.99%.ConclusionsThe OMRON BF 300 monitor satisfies the precision criteria (ICC > 0.95 and low CV) and validation (excellent technical error, ICC > 0.75 and clinically acceptable differences) and is a valid alternative to cutaneous folds as a method of assessing nutrition of the patient

    A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk

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    Binary and multiple star systems are a frequent outcome of the star formation process, and as a result, almost half of all sun-like stars have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large scale fragmentation of turbulent gas cores and filaments or smaller scale fragmentation of a massive protostellar disk due to gravitational instability. Observational evidence for turbulent fragmentation on scales of >>1000~AU has recently emerged. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems. The triple protostar system L1448 IRS3B is an ideal candidate to search for evidence of disk fragmentation. L1448 IRS3B is in an early phase of the star formation process, likely less than 150,000 years in age, and all protostars in the system are separated by <<200~AU. Here we report observations of dust and molecular gas emission that reveal a disk with spiral structure surrounding the three protostars. Two protostars near the center of the disk are separated by 61 AU, and a tertiary protostar is coincident with a spiral arm in the outer disk at a 183 AU separation. The inferred mass of the central pair of protostellar objects is ∼\sim1 Msun_{sun}, while the disk surrounding the three protostars has a total mass of ∼\sim0.30 M_{\sun}. The tertiary protostar itself has a minimum mass of ∼\sim0.085 Msun_{sun}. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150~AU and 320~AU, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.Comment: Published in Nature on Oct. 27th. 24 pages, 8 figure

    Status and Plans for the Array Control and Data Acquisition System of the Cherenkov Telescope Array

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    The Cherenkov Telescope Array (CTA) is the next-generation atmospheric Cherenkov gamma-ray observatory. CTA will consist of two installations, one in the northern, and the other in the southern hemisphere, containing tens of telescopes of different sizes. The CTA performance requirements and the inherent complexity associated with the operation, control and monitoring of such a large distributed multi-telescope array leads to new challenges in the field of the gamma-ray astronomy. The ACTL (array control and data acquisition) system will consist of the hardware and software that is necessary to control and monitor the CTA arrays, as well as to time-stamp, read-out, filter and store -at aggregated rates of few GB/s- the scientific data. The ACTL system must be flexible enough to permit the simultaneous automatic operation of multiple sub-arrays of telescopes with a minimum personnel effort on site. One of the challenges of the system is to provide a reliable integration of the control of a large and heterogeneous set of devices. Moreover, the system is required to be ready to adapt the observation schedule, on timescales of a few tens of seconds, to account for changing environmental conditions or to prioritize incoming scientific alerts from time-critical transient phenomena such as gamma ray bursts. This contribution provides a summary of the main design choices and plans for building the ACTL system.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589
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