294 research outputs found

    Perturbative Chern-Simons Theory From The Penner Model

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    We show explicitly that the perturbative SU(N) Chern-Simons theory arises naturally from two Penner models, with opposite coupling constants. As a result computations in the perturbative Chern-Simons theory are carried out using the Penner model, and it turns out to be simpler and transparent. It is also shown that the connected correlators of the puncture operator in the Penner model, are related to the connected correlators of the operator that gives the Wilson loop operator in the conjugacy class.Comment: 7 Pages, Published Versio

    Multiuser Detection with Decision-Feedback Detectors and PIC in MC-CDMA System

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    In this paper we propose an iterative parallel decision feedback (P-DF) receivers associated with parallel interference cancellation (PIC) for multicarrier code division multiple access (MC-CDMA) systems in a Rayleigh fading channel (cost 207). First the most widely detection techniques, minimum mean-squared error MMSE, Maximum Likelihood ML and PIC were investigated in order to compare their performances in terms of Bit Error Rate (BER) with parallel feedback detection P-DFD. A MMSE DF detector that employs parallel decision-feedback (MMSE-P-DFD) is considered and shows almost the same BER performance with MMSE and ML, which present a better result than the other techniques. In a second time, an iterative proposed method based on the multi-stage techniques P-DFD (parallel DFD with two stages) and PIC was exploited to improve the performance of the system

    Towards a new model of light quality assessment based on occupant satisfaction and lighting glare indices

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    This study looks at the effect of daylighting on human performance. It includes a focus on glare index combined with the actual feeling of users of the classroom as a way to assess indoor lighting quality. The main objective of this research is to understand the impact of daylighting from windows on the glare sensation and also to determine which glare index is the closest to human visual sensation under local daylighting conditions in Biskra, Algeria with highly luminous climate. The study used High Dynamic Range (HDR) photography, Evaglare and Aftab Alpha software to calculate the two glare metrics Daylight Glare, Index (DGI) and the Daylight Glare Probability (DGP). A survey was also used with 90 occupants under different lighting conditions (different configurations) in a design classroom. In order to link the mathematical model and the human assessment of glare, statistical regression analysis was used. We established a statistically compelling connection between daylighting and student performance

    Developing neural networks to investigate relationships between lighting quality and lighting glare indices

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    The present work compares the ability of the two most used glare indices, the Daylight Glare Probability (DGP) and the International Commission on Illumination (CIE) Glare Index (CGI), using Multiple Correspondence Analysis (MCA) and Artificial Neural Networks (ANN). The research investigates the efficiency of indexes in predictive indoor lighting quality. This study was carried out by analyzing data from a survey administered to ninety students in real design classrooms in the city of Biskra, Algeria. The experiment was conducted using three different lighting indoor conditions: natural and artificial lighting and mixed lighting. The true prediction of the Daylight Glare Probability for the variable Comfortable was 60.60%, and for (CIE) Glare Index the prediction values were equal to 44.60% for the same variable

    Insights in the Stock Mixing Dynamics of Atlantic Bluefin Tuna in the North Atlantic

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    Effective fisheries management requires accurate stock identification, which can be challenging in mixed stock fisheries such as the Atlantic bluefin tuna (Thunnus thynnus). This species is currently managed considering two stocks known to spawn in the Mediterranean Sea and Gulf of Mexico, respectively. However, recent studies have shown that individuals from both spawning components can interbreed at a recently discovered spawning ground, located in the Slope Sea. A better understanding of the mixing patterns, as well as the proportion in which both stocks interbreed in the Slope Sea are valuable for a reliable Atlantic bluefin tuna stock assessment. With this aim, we assigned genetic origin of 2000 individuals captured at feeding aggregates across the North Atlantic using a 96 SNP panel and analyzed the genetic profile of 500 individuals including 200 potential Slope Sea spawners (i.e., spawning capable individuals captured in this area at the spawning season), using a 8000 SNP array. We confirmed that stock mixing occurs across different feeding aggregates in the North Atlantic, being stronger in the Northwest Atlantic, where the Mediterranean component was a majority at some locations within and near the Slope Sea spawning ground. The analysis of Slope Sea spawner candidate individuals showed nearly equal representation from both Mediterranean and Gulf of Mexico genetic origin individuals, suggesting similar contribution to the Slope Sea origin offspring. Our findings constitute an important progress towards the understanding of the Atlantic bluefin tuna stock mixing dynamics and the relevance of the recently discovered Slope Sea spawning ground for the conservation of the species.En prens

    Renal cell carcinoma in children: Case report and literature review

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    Renal cell carcinoma is infrequent in children; consequently it is important to communicate its diagnosis and follow up. The behaviour of this type of tumor is better characterized in adults and in this setting the treatment of choice is surgical resection. However, the place of chemo- and radiotherapy has not been well defined. Here, we present a 9-year-old boy with renal cell carcinoma demonstrating only hematuria without any pathological physical examination findings. The mass was described by abdominal ultrasonography and computed tomography in the left kidney. After the left nephroureterectomy, the patient was given no adjuvant therapy

    Thyroid hormone receptor binding to DNA and T(3)-dependent transcriptional activation are inhibited by uremic toxins

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    BACKGROUND: There is a substantial clinical overlap between chronic renal failure (CRF) and hypothyroidism, suggesting the presence of hypothyroidism in uremic patients. Although CRF patients have low T(3 )and T(4 )levels with normal thyroid-stimulating hormone (TSH), they show a higher prevalence of goiter and evidence for blunted tissue responsiveness to T(3 )action. However, there are no studies examining whether thyroid hormone receptors (TRs) play a role in thyroid hormone dysfunction in CRF patients. To evaluate the effects of an uremic environment on TR function, we investigated the effect of uremic plasma on TRβ1 binding to DNA as heterodimers with the retinoid X receptor alpha (RXRα) and on T(3)-dependent transcriptional activity. RESULTS: We demonstrated that uremic plasma collected prior to hemodialysis (Pre-HD) significantly reduced TRβ1-RXRα binding to DNA. Such inhibition was also observed with a vitamin D receptor (VDR) but not with a peroxisome proliferator-activated receptor gamma (PPARγ). A cell-based assay confirmed this effect where uremic pre-HD ultrafiltrate inhibited the transcriptional activation induced by T(3 )in U937 cells. In both cases, the inhibitory effects were reversed when the uremic plasma and the uremic ultrafiltrate were collected and used after hemodialysis (Post-HD). CONCLUSION: These results suggest that dialyzable toxins in uremic plasma selectively block the binding of TRβ1-RXRα to DNA and impair T(3 )transcriptional activity. These findings may explain some features of hypothyroidism and thyroid hormone resistance observed in CRF patients

    Standard survey methods for estimating colony losses and explanatory risk factors in Apis mellifera

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    This chapter addresses survey methodology and questionnaire design for the collection of data pertaining to estimation of honey bee colony loss rates and identification of risk factors for colony loss. Sources of error in surveys are described. Advantages and disadvantages of different random and non-random sampling strategies and different modes of data collection are presented to enable the researcher to make an informed choice. We discuss survey and questionnaire methodology in some detail, for the purpose of raising awareness of issues to be considered during the survey design stage in order to minimise error and bias in the results. Aspects of survey design are illustrated using surveys in Scotland. Part of a standardized questionnaire is given as a further example, developed by the COLOSS working group for Monitoring and Diagnosis. Approaches to data analysis are described, focussing on estimation of loss rates. Dutch monitoring data from 2012 were used for an example of a statistical analysis with the public domain R software. We demonstrate the estimation of the overall proportion of losses and corresponding confidence interval using a quasi-binomial model to account for extra-binomial variation. We also illustrate generalized linear model fitting when incorporating a single risk factor, and derivation of relevant confidence intervals
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