58 research outputs found

    THE GROUND LEVEL CONCENTRATION FROM A POINT SOURCE

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    The Advection-Diffusion Equation (ADE) is solved for a constant pollutant emission from a point-like source placed inside an unstable Atmospheric Boundary Layer (ABL). The solution is obtained adopting the novel analytical approach named Generalized Integral Laplace Transform Technique (GILTT). The concentration solution of the equation is expressed through an infinite series expansion. After setting a realistic scenario through the wind and diffusivity parameterizations the Ground Level Concentration (GLC) is worked out, then an explicit approximate expression is provided for it allowing an analytic simple expression for the position and value of the maximum. Remarks arise on the ability to express value and position of the GLC as an explicit function of the parameters defining the ABL scenario and the source height

    Effect of strong magnetic field on the first-order electroweak phase transition

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    The broken-symmetry electroweak vacuum is destabilized in the presence of a magnetic field stronger than a critical value. Such magnetic field may be generated in the phase transition and restore the symmetry inside the bubbles. A numerical calculation indicates that the first-order phase transition is delayed but may be completed for a sufficient low value of the Higgs mass unless the magnetic field is extremely high.Comment: 7 pages including 2 figures, uses epsf.sty; discussion regarding cosmological consequences (e.g. on baryogenesis) enlarged, some references added and a few misprints correcte

    Assessment of the numerical diffusion effect in the advection of a passive tracer in BOLCHEM

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    The effects of the numericalsc heme implemented in the advection equation of BOLCHEM have been quantified with reference to the diffusion of a passive tracer. An equivalent horizontal diffusion coefficient has been measured and is found to be dependent on wind field and resolution

    Mesenchymal Stromal Cell Therapy in the Management of Perianal Fistulas in Crohn’s Disease. An Up-To-Date Review

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    Crohn's Disease (CD) is a chronic inflammatory disorder that potentially involves the entire gastrointestinal tract. Perianal fistulizing CD (pCD) is a serious and frequent complication associated with significant morbidities and a heavy negative impact on quality of life. The aim of CD treatment is to induce and maintain disease remission and to promote mucosal repair. Unfortunately, even the best therapeutic regimens in pCD do not have long-term efficacy and cause a significant number of side effects. Therefore, it is mandatory to study new therapeutical options such as the use of mesenchymal stromal cells (MSCs). These cells promote tissue repair via the induction of immunomodulation. The present review aims to analyze the existing updated scientific literature on MSCs adoption in the treatment of pCD to evaluate its efficacy and safety and to compare the use of bone marrow and adipose tissue derived MSCs, type of administration, and dose required for recovery

    Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

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    Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

    Higgs boson masses in a non-minimal supersymmetric model

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    A study of the neutral Higgs spectrum in a general Z sub 3 -breaking Next to Minimal Supersymmetric Standard Model (NMSSM) is reported in several significant contexts. Particular attention has been devoted to the upper bound on lightest Higgs boson. In the CP-conserving case we show that the extra terms involved in the general Z sub 3 -breaking superpotential do not affect the upper bound which remains unchanged: it is approx 136 GeV when tan beta = 2.7. The Spontaneous CP Violation scenario in the Z sub 3 -breaking NMSSM can occur at tree-level. When the phases of the fields are small the spectrum shows the lightest Higgs particle to be an almost singlet CP-odd. The second lightest particle, a doublet almost-CP-even state, still manifests the upper bound of the CP-conserving case. When the CP-violating phases are large the lightest particle is a doublet with no definite CP parity and its mass shows the usual upper bound at approx 136 GeV. The large number of parameters involved in the effective potential can be significantly reduced in the Infrared Quasi Fixed Point (IRQFP) resulting after solving the Renormalization Group (RG) equations assuming universality for the soft SUSY breaking masses. In the Z sub 3 -breaking NMSSM, unlike the Z sub 3 -conserving NMSSM, it is possible to find a Higgs spectrum which is still compatible with both experiment and universality at the unification scale. Because in the IRQFP regime tan beta approx 1.8 and the stop mixing parameter is reduced then the upper bound on the lightest Higgs boson turns out to be approx 121 GeV. This result is compatible with experimental data coming from LEPII and might be one of the next predictions to be tested at hadron collider experiments
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