429 research outputs found

    Composite Dirac Neutrinos

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    We present a mechanism that naturally produces light Dirac neutrinos. The basic idea is that the right-handed neutrinos are composite. Any realistic composite model must involve `hidden flavor' chiral symmetries. In general some of these symmetries may survive confinement, and in particular, one of them manifests itself at low energy as an exact BLB-L symmetry. Dirac neutrinos are therefore produced. The neutrinos are naturally light due to compositeness. In general, sterile states are present in the model, some of them can naturally be warm dark matter candidates.Comment: 12 pages; Sec. IIC updated; minor corrections; published versio

    On theories of enhanced CP violation in B_s,d meson mixing

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    The DO collaboration has measured a deviation from the standard model (SM) prediction in the like sign dimuon asymmetry in semileptonic b decay with a significance of 3.2 sigma. We discuss how minimal flavour violating (MFV) models with multiple scalar representations can lead to this deviation through tree level exchanges of new MFV scalars. We review how the two scalar doublet model can accommodate this result and discuss some of its phenomenology. Limits on electric dipole moments suggest that in this model the coupling of the charged scalar to the right handed u-type quarks is suppressed while its coupling to the d-type right handed quarks must be enhanced. We construct an extension of the MFV two scalar doublet model where this occurs naturally.Comment: 10 pages, 7 figures, v3 final JHEP versio

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Influencing the properties of dysprosium single-molecule magnets with phosphine, phosphide and phosphinidene ligands

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    Single-molecule magnets are a type of coordination compound that can retain magnetic information at low temperatures. Single-molecule magnets based on lanthanides have accounted for many important advances, including systems with very large energy barriers to reversal of the magnetization, and a di-terbium complex that displays magnetic hysteresis up to 14 K and shows strong coercivity. Ligand design is crucial for the development of new single-molecule magnets: organometallic chemistry presents possibilities for using unconventional ligands, particularly those with soft donor groups. Here we report dysprosium single-molecule magnets with neutral and anionic phosphorus donor ligands, and show that their properties change dramatically when varying the ligand from phosphine to phosphide to phosphinidene. A phosphide-ligated, trimetallic dysprosium single-molecule magnet relaxes via the second-excited Kramers’ doublet, and, when doped into a diamagnetic matrix at the single-ion level, produces a large energy barrier of 256 cm1 and magnetic hysteresis up to 4.4 K

    QCD and strongly coupled gauge theories : challenges and perspectives

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    We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

    Factors Affecting Influenza and Pneumococcal Vaccination Rates in Hemodialysis Patients: A Multicenter Study

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    Tamer Selen,1 Özgür Merhametsiz,2 Kür&scedil;ad Öneç,3 Zafer Ercan,4 Mahmud &Idot;slam,4 Gül&scedil;ah Altun,3 Musa P&inodot;nar,4 Mehmet Emin Demir5 1Nephrology Department, Düzce Atatürk State Hospital, Düzce, Turkey; 2Nephrology Department, Yeniyüzy&inodot;l University Private Gaziosmanpa&scedil;a Hospital, Istanbul, Turkey; 3Nephrology Department, Düzce University Faculty of Medicine Hospital, Düzce, Turkey; 4Nephrology Department, Sakarya University Education and Research Hospital, Sakarya, Turkey; 5Nephrology Department, At&inodot;l&inodot;m University Medicana International Ankara Hospital, Ankara, TurkeyCorrespondence: Tamer Selen, Düzce Atatürk State Hospital, Nephrology Department, Aziziye, &Scedil;ht. Ramazan Gel Cd. No: 7, Merkez/Düzce, 81010, Türkiye, Email [email protected]: In patients with end-stage renal disease (ESRD), infections, particularly pneumonias, are the most common cause of hospital admissions and death after cardiovascular diseases. It is recommended that dialysis patients receive the pneumococcal vaccine every five years and the influenza vaccine annually. Our study aims to determine the awareness and factors affecting influenza and pneumococcal vaccination rates in hemodialysis patients.Patients and Methods: This cross-sectional study was conducted on patients undergoing regular hemodialysis treatment in 10 different hemodialysis centers across 4 cities. After excluding patients with less than one year of hemodialysis duration and those under 18 years of age, 548 patients were included in the study. Patients were administered a 20-item survey via face-to-face interview and electronic medical records.Results: Out of the 548 patients, only 19 (3.5%) had knowledge about the pneumococcal vaccine, while 238 (43.4%) had knowledge about the influenza vaccine. There were 220 patients (20.1%) who had knowledge about both vaccines. Among the patients, 95 (17.3%) had received the pneumococcal vaccine, with 41.1% of them having received it five years ago or more. A significant proportion (33.7%) of the patients could not recall the timing of their vaccination. While 183 (33.4%) patients had not received the influenza vaccine, only 140 (25.5%) had been vaccinated regularly every year. The reasons for not receiving the influenza and pneumococcal vaccines were stated as “I do not feel the need because I do not get the flu“ (25%) and ”I do not know about the pneumonia vaccine” (36.7%), respectively. The ROC curve analysis for the influenza questionnaire score showed an AUC of 0.822 (95% CI 0.787– 0.856), with a p-value of < 0.001. The statistically significant cutoff value for predicting influenza vaccination was determined to be 2.5. In the univariate analysis, dialysis duration (HD duration), diabetes mellitus (DM), and vascular access type were found to be statistically significant. In the multivariate logistic regression analysis, dialysis duration and DM were identified as independent factors predicting a higher level of knowledge about the influenza vaccine (p=0.009, 0.003, and p=0.041). The ROC curve analysis for the pneumococcal questionnaire score showed an AUC of 0.920 (95% CI 0.886– 0.955), with a p-value of < 0.001. The statistically significant cutoff value for predicting pneumococcal vaccination was determined to be 3.5. In the univariate analysis, residence, dialysis duration, and education level were found to be statistically significant. In the multivariate logistic regression analysis, dialysis duration and education level were identified as independent factors predicting a higher level of knowledge about the pneumococcal vaccine (p=0.038, 0.040, and p=0.010).Conclusion: It was observed that awareness and vaccination rates regarding influenza and pneumococcal vaccines were lower in our patients than recommended. We believe that educating patients about vaccines and increasing the sensitivity of hemodialysis physicians, nurses and nephrologists on this issue will increase vaccination rates.Keywords: hemodialysis, influenza, pneumococcal pneumonia, vaccin

    Correlates of loneliness among university students

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    Background The purpose of this study was to investigate level of loneliness, essential needs during university education, and relationships between loneliness, essential needs, and characteristics of university students. A sample comprising 721 students participated in the study. The mean age was 21.58 (SD = 1.73) with a range from 18 to 25. The majority of the students were female (70.6%) and were living in students' dormitory (67.5%) with low (87.8%) income, away from their parents. Methods The UCLA-R loneliness scale and sociodemographic questionnaire which includes an open-ended question on essential needs during university education were administered. Pearson-Product-Moment correlations were used to explore the relationships between participants' loneliness, needs, and characteristics. Results It was found that 60.2% of the participants experienced loneliness. Economical support (81.6%), social interaction (46.9%) and psychosocial support (35%) were the essential needs during university education reported by the participants. The study findings indicate that there were significant relationships between the needs of economical support, social interaction, and loneliness level of university students. Results also show that there were significant relationships among romantic relationship, parents' status and loneliness. Participants' loneliness levels were relatively higher who had not any romantic relationship and were not from married families. Conclusion The findings of this study provided essential information, about Turkish university students, concerning: level of loneliness and relationships that exist among loneliness, needs and sociodemographic characteristics. The findings also suggest implications for psychosocial practice. Because of the mean of loneliness were found to be high (45.49 ± 10.07), for this study, professionals need to pay attention to Turkish university students' psychosocial state, and need to empower them in establishing social relations

    Identification and Filtering of Uncharacteristic Noise in the CMS Hadron Calorimeter

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    Performance of CMS hadron calorimeter timing and synchronization using test beam, cosmic ray, and LHC beam data

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    This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within ±2 ns

    Automated detection of regions of interest for tissue microarray experiments: an image texture analysis

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    BACKGROUND: Recent research with tissue microarrays led to a rapid progress toward quantifying the expressions of large sets of biomarkers in normal and diseased tissue. However, standard procedures for sampling tissue for molecular profiling have not yet been established. METHODS: This study presents a high throughput analysis of texture heterogeneity on breast tissue images for the purpose of identifying regions of interest in the tissue for molecular profiling via tissue microarray technology. Image texture of breast histology slides was described in terms of three parameters: the percentage of area occupied in an image block by chromatin (B), percentage occupied by stroma-like regions (P), and a statistical heterogeneity index H commonly used in image analysis. Texture parameters were defined and computed for each of the thousands of image blocks in our dataset using both the gray scale and color segmentation. The image blocks were then classified into three categories using the texture feature parameters in a novel statistical learning algorithm. These categories are as follows: image blocks specific to normal breast tissue, blocks specific to cancerous tissue, and those image blocks that are non-specific to normal and disease states. RESULTS: Gray scale and color segmentation techniques led to identification of same regions in histology slides as cancer-specific. Moreover the image blocks identified as cancer-specific belonged to those cell crowded regions in whole section image slides that were marked by two pathologists as regions of interest for further histological studies. CONCLUSION: These results indicate the high efficiency of our automated method for identifying pathologic regions of interest on histology slides. Automation of critical region identification will help minimize the inter-rater variability among different raters (pathologists) as hundreds of tumors that are used to develop an array have typically been evaluated (graded) by different pathologists. The region of interest information gathered from the whole section images will guide the excision of tissue for constructing tissue microarrays and for high throughput profiling of global gene expression
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