Search for time-dependent B0s - B0s-bar oscillations using a vertex charge dipole technique

We report a search for B0s - B0s-bar oscillations using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the B0s - B0s-bar oscillation frequency: Delta m_s < 4.9 ps-1 and 7.9 < Delta m_s < 10.3 ps-1 at the 95% confidence level.Comment: 18 pages, 3 figures, replaced by version accepted for publication in Phys.Rev.D; results differ slightly from first versio

Diffractive Dijet Production at sqrt(s)=630 and 1800 GeV at the Fermilab Tevatron

We report a measurement of the diffractive structure function $F_{jj}^D$ of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in $\bar pp$ collisions at $\sqrt s=630$ GeV at the Fermilab Tevatron. The ratio of $F_{jj}^D$ at $\sqrt s=630$ GeV to $F_{jj}^D$ obtained from a similar measurement at $\sqrt s=1800$ GeV is compared with expectations from QCD factorization and with theoretical predictions. We also report a measurement of the $\xi$ ($x$-Pomeron) and $\beta$ ($x$ of parton in Pomeron) dependence of $F_{jj}^D$ at $\sqrt s=1800$ GeV. In the region $0.035<\xi<0.095$, $|t|<1$ GeV$^2$ and $\beta<0.5$, $F_{jj}^D(\beta,\xi)$ is found to be of the form $\beta^{-1.0\pm 0.1} \xi^{-0.9\pm 0.1}$, which obeys $\beta$-$\xi$ factorization.Comment: LaTeX, 9 pages, Submitted to Phys. Rev. Letter

A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab

We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) = (1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)

Periodic density functional theory calculations of bulk and the (010) surface of goethite

<p>Abstract</p> <p>Background</p> <p>Goethite is a common and reactive mineral in the environment. The transport of contaminants and anaerobic respiration of microbes are significantly affected by adsorption and reduction reactions involving goethite. An understanding of the mineral-water interface of goethite is critical for determining the molecular-scale mechanisms of adsorption and reduction reactions. In this study, periodic density functional theory (DFT) calculations were performed on the mineral goethite and its (010) surface, using the Vienna <it>Ab Initio </it>Simulation Package (VASP).</p> <p>Results</p> <p>Calculations of the bulk mineral structure accurately reproduced the observed crystal structure and vibrational frequencies, suggesting that this computational methodology was suitable for modeling the goethite-water interface. Energy-minimized structures of bare, hydrated (one H₂O layer) and solvated (three H₂O layers) (010) surfaces were calculated for 1 × 1 and 3 × 3 unit cell slabs. A good correlation between the calculated and observed vibrational frequencies was found for the 1 × 1 solvated surface. However, differences between the 1 × 1 and 3 × 3 slab calculations indicated that larger models may be necessary to simulate the relaxation of water at the interface. Comparison of two hydrated surfaces with molecularly and dissociatively adsorbed H₂O showed a significantly lower potential energy for the former.</p> <p>Conclusion</p> <p>Surface Fe-O and (Fe)O-H bond lengths are reported that may be useful in surface complexation models (SCM) of the goethite (010) surface. These bond lengths were found to change significantly as a function of solvation (i.e., addition of two extra H₂O layers above the surface), indicating that this parameter should be carefully considered in future SCM studies of metal oxide-water interfaces.</p

Small Interfering RNA Targeted to IGF-IR Delays Tumor Growth and Induces Proinflammatory Cytokines in a Mouse Breast Cancer Model

Insulin-like growth factor I (IGF-I) and its type I receptor (IGF-IR) play significant roles in tumorigenesis and in immune response. Here, we wanted to know whether an RNA interference approach targeted to IGF-IR could be used for specific antitumor immunostimulation in a breast cancer model. For that, we evaluated short interfering RNA (siRNAs) for inhibition of in vivo tumor growth and immunological stimulation in immunocompetent mice. We designed 2′-O-methyl-modified siRNAs to inhibit expression of IGF-IR in two murine breast cancer cell lines (EMT6, C4HD). Cell transfection of IGF-IR siRNAs decreased proliferation, diminished phosphorylation of downstream signaling pathway proteins, AKT and ERK, and caused a G0/G1 cell cycle block. The IGF-IR silencing also induced secretion of two proinflammatory cytokines, TNF- α and IFN-γ. When we transfected C4HD cells with siRNAs targeting IGF-IR, mammary tumor growth was strongly delayed in syngenic mice. Histology of developing tumors in mice grafted with IGF-IR siRNA treated C4HD cells revealed a low mitotic index, and infiltration of lymphocytes and polymorphonuclear neutrophils, suggesting activation of an antitumor immune response. When we used C4HD cells treated with siRNA as an immunogen, we observed an increase in delayed-type hypersensitivity and the presence of cytotoxic splenocytes against wild-type C4HD cells, indicative of evolving immune response. Our findings show that silencing IGF-IR using synthetic siRNA bearing 2′-O-methyl nucleotides may offer a new clinical approach for treatment of mammary tumors expressing IGF-IR. Interestingly, our work also suggests that crosstalk between IGF-I axis and antitumor immune response can mobilize proinflammatory cytokines

Manovacuometria realizada por meio de traqueias de diferentes comprimentos

Manovacuometry is a simple, fast, and non-invasive test, with maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) obtained to assist respiratory muscle assessment. Currently, there is a wide variety of models and brands of manovacuometers with different trachea diameters and lengths. However, the interference of these models in the measurements obtained by these equipments needs to be investigated. Thus, this study mainly aimed to verify the influence of tracheal length on maximal respiratory pressures (MRP), obtained by an analog manovacuometer, in healthy individuals. Our secondary objective was to verify the correlation between measurements. Fifty individuals, aged 18 to 30, of both sexes, were evaluated by spirometry and manovacuometry. MIP and MEP were performed using tracheas with same internal diameter (0.5 cm) and 30 cm, 60 cm, and 90 cm length. Significantly lower MIP values were observed when comparing a 90 cm trachea to 30 and 60 cm tracheas (Friedman’s ANOVA test and Wilcoxon test with Bonferroni adjustment). Tracheas with 30, 60, and 90 cm length and same diameter did not affect MIP and MEP values, except the 90 cm trachea for MIP values, which may interfere in the physical therapy clinical practice. Further studies are required to analyze the need for standardizing the trachea length used in manovacuometers.La manovacuometría es una prueba sencilla, rápida y no invasiva por la cual se obtienen la presión inspiratoria máxima (PImax) y la presión espiratoria máxima (PEmax), con el objetivo de ayudar en el examen muscular respiratorio. Hoy día se encuentran una gran variedad de modelos y marcas de manovacuometros, con diferentes diámetros y longitudes de las tráqueas, pero hacen falta estudios sobre la interferencia de estos modelos en las mediciones por este instrumento. En este texto se propone examinar en sujetos sanos, en primer lugar, la influencia en la longitud de las tráqueas en las presiones respiratorias máximas, obtenidas por manovacuometros analógicos, y en segundo lugar comprobar la existencia de correlación entre las mediciones. Se evaluaron a cincuenta sujetos entre 18 y 30 años de edad, tanto varones como mujeres, empleando la espirometría y la manovacuometría. Se midió la PImax y la PEmax empleando tráqueas de mismo diámetro interno (0,5 cm) y con longitudes de 30, 60 e 90 cm. Se observaron valores significativamente menores de PImax con la tráquea de longitud de 90 cm en comparación con las PImax con las tráqueas de 30 y 60 cm (prueba de Friedman’s ANOVA, la de Wilcoxon con ajustes de Bonferroni). Las tráqueas de 30, 60 y 90 cm de longitud y mismo diámetro no influyeron en los valores de la PEmax y de la PImax, con excepción de la tráquea de 90 cm en los valores de la PImax, lo que puede interferir la práctica clínica fisioterapéutica. Se necesitan más estudios para evaluar la necesidad de estándares de la longitud de tráqueas empleadas en manovacuometros.A manovacuometria é um teste simples, rápido e não invasivo por meio do qual a pressão inspiratória máxima (PImáx) e a pressão expiratória máxima (PEmáx) são obtidas, a fim de auxiliar na avaliação muscular respiratória. Atualmente, há grande variedade de modelos e marcas de manovacuômetros, com diferentes diâmetros e comprimentos de traqueias, no entanto, a interferência desses modelos nas medidas obtidas por esses equipamentos necessita de investigação. Desta forma, o objetivo primário deste estudo foi verificar a influência do comprimento de traqueias nas pressões respiratórias máximas, obtidas por meio de manovacuômetro analógico, em indivíduos saudáveis e, secundariamente, se há correlação entre as medidas. Foram avaliados 50 indivíduos, de 18 a 30 anos, de ambos os sexos, por meio da espirometria e manovacuometria. As PImáx e PEmáx foram realizadas com uso de traqueias de mesmo diâmetro interno (0,5 cm) e comprimentos de 30, 60 e 90 cm. Foram observados valores significativamente menores de PImáx obtidos com a traqueia de comprimento de 90 cm comparados às PImáx obtidas com as traqueias de 30 e 60 cm (teste de Friedman’s ANOVA com teste de Wilcoxon com ajuste de Bonferroni). As traqueias de 30, 60 e 90 cm de comprimento e mesmo diâmetro não influenciaram os valores de PEmáx e PImáx, exceto a traqueia de 90 cm para os valores de PImáx, o que pode interferir na prática clínica fisioterapêutica. Novos estudos são necessários para analisar a necessidade de padronização do comprimento da traqueia utilizada em manovacuômetros

Multi-messenger observations of a binary neutron star merger

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

Search for Single-Top-Quark Production in p-pbar Collisions at sqrt(s)=1.8 TeV

We search for standard model single-top-quark production in the W-gluon fusion and W* channels using 106 pb^-1 of data from p-pbar collisions at sqrt(s)=1.8 TeV collected with the Collider Detector at Fermilab. We set an upper limit at 95% C.L. on the combined W-gluon fusion and W* single-top cross section of 14 pb, roughly six times larger than the standard model prediction. Separate 95% C.L. upper limits in the W-gluon fusion and W* channels are also determined and are found to be 13 and 18 pb, respectively.Comment: 6 pages, 2 figures; submitted to Phys. Rev. Let