539 research outputs found

    Electromagnetic radiation produced by avalanches in the magnetization reversal of Mn12-Acetate

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    Electromagnetic radiation produced by avalanches in the magnetization reversal of Mn12-Acetate has been measured. Short bursts of radiation have been detected, with intensity significantly exceeding the intensity of the black-body radiation from the sample. The model based upon superradiance from inversely populated spin levels has been suggested

    NGC 5694: another foster son of the Galactic Halo

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    We present the results of the analysis of high-resolution spectra obtained with UVES-FLAMES@VLT for six red giant branch stars in the outer-halo metal-poor ([Fe/H]I=-1.98 and [Fe/H]II=-1.83) Galactic globular cluster NGC 5694, which has been suggested as a possible incomer by Lee et al. (2006) based on the anomalous chemical composition of a single cluster giant. We obtain accurate abundances for a large number of elements and we find that: (a) the six target stars have the same chemical composition within the uncertainties, except for Na and Al; (b) the average cluster abundance of \alpha\ elements (with the only exception of Si) is nearly solar, at odds with typical halo stars and globular clusters of similar metallicity; (c) Y, Ba, La and Eu abundances are also significantly lower than in Galactic field stars and star clusters of similar metallicity. Hence we confirm the Lee et al. classification of NGC 5694 as a cluster of extra-galactic origin. We provide the first insight on the Na-O and Mg-Al anti-correlations in this cluster: all the considered stars have very similar abundance ratios for these elements, except one that has significantly lower [Na/Fe] and [Al/Fe] ratios, suggesting that some degree of early self-enrichment has occurred also in this cluster.Comment: Accepted for publication by MNRAS. 15 pages, 8 figures, 4 table

    Penataan Kawasan Kumuh Kampung Pulo, Kelurahan Kampung Melayu, Kecdamatan Jatinegara Jakarta Timur

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    Berdasarkan berbagai potensi dan kendala yang dimiliki kota Jakarta, arahan RTRW 2010 serta sasaran ruang terbuka hijau yang diinginkan maka dikembangkan konsepsi utama rancangan fisik ruang terbuka hijau berbentuk linier/ koridor yang menyebar secara fisik dalam kota. Sasaran dari pengelolaan ruang terbuka hijau di DKI Jakarta adalah ruang terbuka hijau yang dapat mengatasi permasalahan lingkungan kota, dapat meningkatkan kualitas visual kota, dan juga memberikan dampak positif terhadap tingkat kesejahteraan sosial warganya. Sasaran secara kualitatif adalah untuk mendapatkan kualitas lingkungan fisik kota dan secara kuantitatif adalah untuk mendapat jumlah luasan ruang terbuka hijau kurang lebih 9.250 ha (13,94 %) dari luas kota Jakarta. Berdasarkan pengamatan diambil kesimpulan yaitu ; kondisi fisik pedestrian saat ini belum memenuhi standar yang layak dan belum mengakomodasikan kebutuhan fasilitas pendukung untuk Kenyamanan, keselamatan, dan keamanan lalu lintas pejalan kaki termasuk pejalan kaki dengan keterbatasan fisik dan stamina, serta terdapat fungsi-fungsi lain oleh keberadaan pedagang kaki lima yang menggunakan ruang gerak bebas pejalan kaki. Dengan adanya taman kota Menteng yang berkualitas dan dapat diakses oleh masyarakat umum sehingga dapat mengurangi permasalahan kurangnya fasilitas umum di kecamatan Menteng khususnya. Maksud tujuan studi ini adalah menemukenali potensi dan permasalahan taman Menteng sebagai taman kota serta kriteria kualitas taman berdasarkan nilai keinginan dan kepuasan pengguna atau pengunjung yang datang. Dari hasil analisa dapat diperoleh bahwa taman Menteng sebagai taman kota berdasarkan kriteria kualitas taman terdapat kekurangan seperti penerangan lampu, penertiban parkir motor dan perawatan. Kesimpulannya adalah taman kota Menteng berdasarkan kriteria kualitas taman sudah baik jika benar-benar dijaga oleh dirawat secara berkala dan kerjasama antara pihak-pihak terkait yaitu pemerintah, swasta/pengelola dan masyarakat sebagai pengguna

    Kinematics of a globular cluster with an extended profile: NGC5694

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    We present a study of the kinematics of the remote globular cluster NGC5694 based on GIRAFFE@VLT medium resolution spectra. A sample of 165 individual stars selected to lie on the Red Giant Branch in the cluster Color Magnitude Diagram was considered. Using radial velocity and metallicity from Calcium triplet, we were able to select 83 bona-fide cluster members. The addition of six previously known members leads to a total sample of 89 cluster giants with typical uncertainties <1.0 km/s in their radial velocity estimates. The sample covers a wide range of projected distances from the cluster center, from ~0.2 arcmin to 6.5 arcmin = 23 half-light radii (r_h). We find only very weak rotation, as typical of metal-poor globular clusters. The velocity dispersion gently declines from a central value of sigma=6.1 km/s to sigma = 2.5 km/s at ~2 arcmin = 7.1= r_h, then it remainins flat out to the next (and last) measured point of the dispersion profile, at ~4 arcmin = 14.0 r_h, at odds with the predictions of isotropic King models. We show that both isotropic single-mass non-collisional models and multi-mass anisotropic models can reproduce the observed surface brightness and velocity dispersion profiles.Comment: Accepted for publication by MNRAS. Pdflatex, 10 pages, 10 figure

    ENGINES: exploring single nucleotide variation in entire human genomes

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    <p>Abstract</p> <p>Background</p> <p>Next generation ultra-sequencing technologies are starting to produce extensive quantities of data from entire human genome or exome sequences, and therefore new software is needed to present and analyse this vast amount of information. The 1000 Genomes project has recently released raw data for 629 complete genomes representing several human populations through their Phase I interim analysis and, although there are certain public tools available that allow exploration of these genomes, to date there is no tool that permits comprehensive population analysis of the variation catalogued by such data.</p> <p>Description</p> <p>We have developed a genetic variant site explorer able to retrieve data for Single Nucleotide Variation (SNVs), population by population, from entire genomes without compromising future scalability and agility. ENGINES (ENtire Genome INterface for Exploring SNVs) uses data from the 1000 Genomes Phase I to demonstrate its capacity to handle large amounts of genetic variation (>7.3 billion genotypes and 28 million SNVs), as well as deriving summary statistics of interest for medical and population genetics applications. The whole dataset is pre-processed and summarized into a data mart accessible through a web interface. The query system allows the combination and comparison of each available population sample, while searching by rs-number list, chromosome region, or genes of interest. Frequency and F<sub>ST </sub>filters are available to further refine queries, while results can be visually compared with other large-scale Single Nucleotide Polymorphism (SNP) repositories such as HapMap or Perlegen.</p> <p>Conclusions</p> <p>ENGINES is capable of accessing large-scale variation data repositories in a fast and comprehensive manner. It allows quick browsing of whole genome variation, while providing statistical information for each variant site such as allele frequency, heterozygosity or F<sub>ST </sub>values for genetic differentiation. Access to the data mart generating scripts and to the web interface is granted from <url>http://spsmart.cesga.es/engines.php</url></p

    Lameness detection challenges in automated milking systems addressed with partial least squares discriminant analysis

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    AbstractLameness causes decreased animal welfare and leads to higher production costs. This study explored data from an automatic milking system (AMS) to model on-farm gait scoring from a commercial farm. A total of 88 cows were gait scored once per week, for 2 5-wk periods. Eighty variables retrieved from AMS were summarized week-wise and used to predict 2 defined classes: nonlame and clinically lame cows. Variables were represented with 2 transformations of the week summarized variables, using 2-wk data blocks before gait scoring, totaling 320 variables (2×2×80). The reference gait scoring error was estimated in the first week of the study and was, on average, 15%. Two partial least squares discriminant analysis models were fitted to parity 1 and parity 2 groups, respectively, to assign the lameness class according to the predicted probability of being lame (score 3 or 4/4) or not lame (score 1/4). Both models achieved sensitivity and specificity values around 80%, both in calibration and cross-validation. At the optimum values in the receiver operating characteristic curve, the false-positive rate was 28% in the parity 1 model, whereas in the parity 2 model it was about half (16%), which makes it more suitable for practical application; the model error rates were, 23 and 19%, respectively. Based on data registered automatically from one AMS farm, we were able to discriminate nonlame and lame cows, where partial least squares discriminant analysis achieved similar performance to the reference method

    Experienced and inexperienced observers achieved relatively high within-observer agreement on video mobility scoring of dairy cows

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    AbstractAssessment of lameness prevalence and severity requires visual evaluation of thelocomotion of a cow. Welfare schemes including locomotion assessments are increasingly being adopted, and more farmers and their veterinarians might implement a locomotion-scoring routine together. However, high within-observer agreement is a prerequisite for obtaining valid mobility scorings, and within-observer agreement cannot be estimated in a barn, because the gait of cows is dynamic and may change between 2 occasions. The objective of this study was to estimate the within-observer agreement according to the observers’ educational background and experience with cattle, based on video recordings with very diverse types of gait. Groups of farmers, bovine veterinarians, first- and fourth-year veterinary students, researchers, and cattle-inexperienced sensory assessors evaluated mobility using a 5-point mobility score system developed specifically for walking cows (n=102 observers). The evaluation sessions were similar for all groups, lasted 75 min, and were organized as follows: introduction, test A, short training session, break, and test B. In total, video recordings of 22 cows were displayed twice in a random order (11 cows in each test × 2 replicates). Data were analyzed applying kappa coefficient, logistic regression, and testing for random effects of observers. The crude estimates of 95% confidence interval for weighted kappa in test A and B ranged, respectively, from 0.76 to 0.80 and 0.70 to 0.75. When adjusting for the fixed effects of video sample and gait scoring preferences, the probability of assigning the same mobility score twice to the same cow varied from 55% (sensory assessors) to 72% (fourth-year veterinary students). The random effect of the individual observers was negligible. That is, in general observers could categorize the mobility characteristics of cows quite well. Observers who preferred to assess the attributes back arch or the overall mobility score (based on uneven gait) had the highest agreement, respectively, 69 or 68%. The training session seemed insufficient to improve agreement. Nonetheless, even novice observers were able to achieve perfect agreement up to 60% of the 22 scorings with merely the experience obtained during the study (introduction and training session). The relatively small differences between groups, together with a high agreement, demonstrate that the new system is easy to follow compared with previously described scoring systems. The mobility score achieves sufficiently high within-observer repeatability to allow between-observer agreement estimates, which are reliable compared with other more-complex scoring systems. Consequently, the new scoring scale seems feasible for on-farm applications as a tool to monitor mobility within and between cows, for communication between farmers and veterinarians with diverse educational background, and for lamenessbenchmarking of herds

    R-symmetric Gauge Mediation and the MRSSM

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    This is an invited summary of a seminar talk given at various institutions in the United States and Canada. After a brief introduction, a review of the minimal R-symmetric supersymmetric standard model is given, and the benefits to the flavor sector are discussed. R-symmetric gauge mediation is an attempt to realize this model using metastable supersymmetry breaking techniques. Sample low energy spectra are presented and tuning is discussed. Various other phenomenological results are summarized.Comment: 14 pages, invited Brief Review, submitted to Modern Physics Letters A; v2: replaced Figure 1, updated acknowledgments, fixed typo

    Quadratic transverse anisotropy term due to dislocations in Mn12-Ac directly obtained by EPR spectroscopy

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    High-Sensitivity Electron Paramagnetic Resonance experiments have been carried out in fresh and stressed Mn12-Acetate single crystals for frequencies ranging from 40 GHz up to 110 GHz. The high number of crystal dislocations formed in the stressing process introduces a E(S_x^2-S_y^2) transverse anisotropy term in the spin hamiltonian. From the behaviour of the resonant absorptions on the applied transverse magnetic field we have obtained an average value for E = 22 mK, corresponding to a concentration of dislocations per unit cell of c = 10^-3.Comment: 13 pages and 4 figure

    A novel accelerometry-based algorithm for the detection of step durations over short episodes of gait in healthy elderly.

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    Background: The assessment of short episodes of gait is clinically relevant and easily implemented, especially given limited space and time requirements. BFS (body-fixed-sensors) are small, lightweight and easy to wear sensors, which allow the assessment of gait at relative low cost and with low interference. Thus, the assessment with BFS of short episodes of gait, extracted from dailylife physical activity or measured in a standardised and supervised setting, may add value in the study of gait quality of the elderly. The aim of this study was to evaluate the accuracy of a novel algorithm based on acceleration signals recorded at different human locations (lower back and heels) for the detection of step durations over short episodes of gait in healthy elderly subjects.Methods: Twenty healthy elderly subjects (73.7 ± 7.9 years old) walked twice a distance of 5 m, wearing a BFS on the lower back, and on the outside of each heel. Moreover, an optoelectronic three-dimensional (3D) motion tracking system was used to detect step durations. A novel algorithm is presented for the detection of step durations from low-back and heel acceleration signals separately. The accuracy of the algorithm was assessed by comparing absolute differences in step duration between the three methods: step detection from the optoelectronic 3D motion tracking system, step detection from the application of the novel algorithm to low-back accelerations, and step detection from the application of the novel algorithm to heel accelerations.Results: The proposed algorithm successfully detected all the steps, without false positives and without false negatives. Absolute average differences in step duration within trials and across subjects were calculated for each comparison, between low-back accelerations and the optoelectronic system were on average 22.4 ± 7.6 ms (4.0 ± 1.3 % of average step duration), between heel accelerations and the optoelectronic system were on average 20.7 ± 11.8 ms (3.7 ± 1.9 %), and between low-back accelerations and heel accelerations were on average 27.8 ± 15.1 ms (4.9 ± 2.5 % of average step duration).Conclusions: This study showed that the presented novel algorithm detects step durations over short episodes of gait in healthy elderly subjects with acceptable accuracy from low-back and heel accelerations, which provides opportunities to extract a range of gait parameters from short episodes of gait
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