661 research outputs found

    Evidence for an excess of B -> D(*) Tau Nu decays

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    Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg

    Impacts of organic and conventional crop management on diversity and activity of free-living nitrogen fixing bacteria and total bacteria are subsidiary to temporal effects

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    A three year field study (2007-2009) of the diversity and numbers of the total and metabolically active free-living diazotophic bacteria and total bacterial communities in organic and conventionally managed agricultural soil was conducted at the Nafferton Factorial Systems Comparison (NFSC) study, in northeast England. The result demonstrated that there was no consistent effect of either organic or conventional soil management across the three years on the diversity or quantity of either diazotrophic or total bacterial communities. However, ordination analyses carried out on data from each individual year showed that factors associated with the different fertility management measures including availability of nitrogen species, organic carbon and pH, did exert significant effects on the structure of both diazotrophic and total bacterial communities. It appeared that the dominant drivers of qualitative and quantitative changes in both communities were annual and seasonal effects. Moreover, regression analyses showed activity of both communities was significantly affected by soil temperature and climatic conditions. The diazotrophic community showed no significant change in diversity across the three years, however, the total bacterial community significantly increased in diversity year on year. Diversity was always greatest during March for both diazotrophic and total bacterial communities. Quantitative analyses using qPCR of each community indicated that metabolically active diazotrophs were highest in year 1 but the population significantly declined in year 2 before recovering somewhat in the final year. The total bacterial population in contrast increased significantly each year. Seasonal effects were less consistent in this quantitative study

    Search for the decay modes D^0 → e^+e^-, D^0 → μ^+μ^-, and D^0 → e^±μ∓

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    We present searches for the rare decay modes D^0→e^+e^-, D^0→μ^+μ^-, and D^0→e^±μ^∓ in continuum e^+e^-→cc events recorded by the BABAR detector in a data sample that corresponds to an integrated luminosity of 468  fb^(-1). These decays are highly Glashow–Iliopoulos–Maiani suppressed but may be enhanced in several extensions of the standard model. Our observed event yields are consistent with the expected backgrounds. An excess is seen in the D^0→μ^+μ^- channel, although the observed yield is consistent with an upward background fluctuation at the 5% level. Using the Feldman–Cousins method, we set the following 90% confidence level intervals on the branching fractions: B(D^0→e^+e^-)<1.7×10^(-7), B(D^0→μ^+μ^-) within [0.6,8.1]×10^(-7), and B(D^0→e^±μ^∓)<3.3×10^(-7)

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Differences in access to coronary care unit among patients with acute myocardial infarction in Rome: old, ill, and poor people hold the burden of inefficiency

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    BACKGROUND: Direct admission to Coronary Care Unit (CCU) on hospital arrival can be considered as a good proxy for adequate management in patients with acute myocardial infarction (AMI), as it has been associated with better prognosis. We analyzed a cohort of patients with AMI hospitalized in Rome (Italy) in 1997–2000 to assess the proportion directly admitted to CCU and to investigate the effect of patient characteristics such as gender, age, illness severity on admission, and socio-economic status (SES) on CCU admission practices. METHODS: Using discharge data, we analyzed a cohort of 9127 AMI patients. Illness severity on admission was determined using the Deyo's adaptation of the Charlson's comorbidity index, and each patient was assigned to one to four SES groups (level I referring to the highest SES) defined by a socioeconomic index, derived by the characteristics of the census tract of residence. The effect of gender, age, illness severity and SES, on risk of non-admission to CCU was investigated using a logistic regression model (OR, CI 95%). RESULTS: Only 53.9% of patients were directly admitted to CCU, and access to optimal care was more frequently offered to younger patients (OR = 0.35; 95%CI = 0.25–0.48 when comparing 85+ to >=50 years), those with less severe illness (OR = 0.48; 95%CI = 0.37–0.61 when comparing Charlson index 3+ to 0) and the socially advantaged (OR = 0.81; 95%CI = 0.66–0.99 when comparing low to high SES). CONCLUSION: In Rome, Italy, standard optimal coronary care is underprovided. It seems to be granted preferentially to the better off, even after controversial clinical criteria, such as age and severity of illness, are taken into account

    HLA class II DNA typing in a large series of European patients with systemic lupus erythematosus: correlations with clinical and autoantibody subsets

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    We conducted this study to determine the HLA class II allele associations in a large cohort of patients of homogeneous ethnic derivation with systemic lupus erythematosus (SLE). The large sample size allowed us to stratify patients according to their clinical and serologic characteristics. We studied 577 European Caucasian patients with SLE. Antinuclear antibodies (Hep-2 cells), anti-dsDNA antibodies (Crithidia luciliae), and antibodies to extractable nuclear antigens Ro (SS-A), La (SS-B), U1-RNP, Sm, Jo1, SCL70, and PCNA, were detected in all patients. Molecular typing of HLA-DRB1, DRB3, DQA1, and DQB1 loci was performed by the polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP) method. We found a significantly increased frequency of DRB1*03, DRB1*15, DRB1*16, DQA1*0102, DQB1*0502, DQB1*0602, DQB1*0201, DQB1*0303, and DQB1*0304 in lupus patients as compared with healthy controls. In addition, DRB1*03 was associated with anti-Ro, anti-La, pleuritis, and involvement of lung, kidney, and central nervous system. DRB1*15 and DQB1*0602 were associated with anti-dsDNA antibodies; DQB1*0201 with anti-Ro and anti-La, leukopenia, digital skin vasculitis, and pleuritis; and DQB1*0502 was associated with anti-Ro, renal involvement, discoid lupus, and livedo reticularis. In conclusion, our study shows some new HLA clinical and serologic associations in SLE and further confirms that the role of MHC genes is mainly to predispose to particular serologic and clinical manifestations of this disease

    iNOS Ablation Does Not Improve Specific Force of the Extensor Digitorum Longus Muscle in Dystrophin-Deficient mdx4cv Mice

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    Nitrosative stress compromises force generation in Duchenne muscular dystrophy (DMD). Both inducible nitric oxide synthase (iNOS) and delocalized neuronal NOS (nNOS) have been implicated. We recently demonstrated that genetic elimination of nNOS significantly enhanced specific muscle forces of the extensor digitorum longus (EDL) muscle of dystrophin-null mdx4cv mice (Li D et al J. Path. 223:88–98, 2011). To determine the contribution of iNOS, we generated iNOS deficient mdx4cv mice. Genetic elimination of iNOS did not alter muscle histopathology. Further, the EDL muscle of iNOS/dystrophin DKO mice yielded specific twitch and tetanic forces similar to those of mdx4cv mice. Additional studies suggest iNOS ablation did not augment nNOS expression neither did it result in appreciable change of nitrosative stress markers in muscle. Our results suggest that iNOS may play a minor role in mediating nitrosative stress-associated force reduction in DMD

    Socioeconomic status and hospitalization in the very old: a retrospective study

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    <p>Abstract</p> <p>Background</p> <p>Socioeconomic status could affect the demand for hospital care. The aim of the present study was to assess the role of age, socioeconomic status and comorbidity on acute hospital admissions among elderly.</p> <p>Methods</p> <p>We retrospectively examined the discharge abstracts data of acute care hospital admissions of residents in Rome aged 75 or more years in the period 1997–2000. We used the Hospital Information System of Rome, the Tax Register, and the Population Register of Rome for socio-economic data. The rate of hospitalization, modified Charlson's index of comorbidity, and level of income in the census tract of residence were obtained. Rate ratios and 95% confidence limits were computed to assess the relationship between income deciles and rate of hospitalization. Cross-tabulation was used to explore the distribution of the index of comorbidity by deciles of income. Analyses were repeated for patients grouped according to selected diseases.</p> <p>Results</p> <p>Age was associated with a marginal increase in the rate of hospitalization. However, the hospitalization rate was inversely related to income in both sexes. Higher income was associated with lower comorbidity. The same associations were observed in patients admitted with a principal diagnosis of chronic condition (diabetes mellitus, heart failure, chron obstructive pulmonary disease) or stroke, but not hip fracture.</p> <p>Conclusion</p> <p>Lower social status and associated comorbidity, more than age per se, are associated with a higher rate of hospitalization in very old patients.</p

    Non-native hydrophobic interactions detected in unfolded apoflavodoxin by paramagnetic relaxation enhancement

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    Transient structures in unfolded proteins are important in elucidating the molecular details of initiation of protein folding. Recently, native and non-native secondary structure have been discovered in unfolded A. vinelandii flavodoxin. These structured elements transiently interact and subsequently form the ordered core of an off-pathway folding intermediate, which is extensively formed during folding of this α–β parallel protein. Here, site-directed spin-labelling and paramagnetic relaxation enhancement are used to investigate long-range interactions in unfolded apoflavodoxin. For this purpose, glutamine-48, which resides in a non-native α-helix of unfolded apoflavodoxin, is replaced by cysteine. This replacement enables covalent attachment of nitroxide spin-labels MTSL and CMTSL. Substitution of Gln-48 by Cys-48 destabilises native apoflavodoxin and reduces flexibility of the ordered regions in unfolded apoflavodoxin in 3.4 M GuHCl, because of increased hydrophobic interactions in the unfolded protein. Here, we report that in the study of the conformational and dynamic properties of unfolded proteins interpretation of spin-label data can be complicated. The covalently attached spin-label to Cys-48 (or Cys-69 of wild-type apoflavodoxin) perturbs the unfolded protein, because hydrophobic interactions occur between the label and hydrophobic patches of unfolded apoflavodoxin. Concomitant hydrophobic free energy changes of the unfolded protein (and possibly of the off-pathway intermediate) reduce the stability of native spin-labelled protein against unfolding. In addition, attachment of MTSL or CMTSL to Cys-48 induces the presence of distinct states in unfolded apoflavodoxin. Despite these difficulties, the spin-label data obtained here show that non-native contacts exist between transiently ordered structured elements in unfolded apoflavodoxin
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