977 research outputs found
A full Next to Leading Order study of direct photon pair production in hadronic collisions
We discuss the production of photon pairs in hadronic collisions, from fixed
target to LHC energies. The study which follows is based on a QCD calculation
at full next-to-leading order accuracy, including single and double
fragmentation contributions, and implemented in the form of a general purpose
computer program of "partonic event generator" type. To illustrate the
possibilities of this code, we present the comparison with observables measured
by the WA70 and D0 collaborations, and some predictions for the irreducible
background to the search of Higgs bosons at LHC in the channel . We also discuss theoretical scale uncertainties for these predictions,
and examine several infrared sensitive situations which deserve further study.Comment: 45 pages Latex, 16 eps files plus some metafont files; replaced by
the version to appear in Eur. Phys. J.
Stable One-Dimensional Integral Representations of One-Loop N-Point Functions in the General Massive Case: I - Three Point Functions
In this article we provide representations for the one-loop three point
functions in 4 and 6 dimensions in the general case with complex masses. The
latter are part of the GOLEM library used for the computation of one-loop
multileg amplitudes. These representations are one-dimensional integrals
designed to be free of instabilites induced by inverse powers of Gram
determinants, therefore suitable for stable numerical implementations.Comment: 40 pages, 1 figur
A critical phenomenological study of inclusive photon production in hadronic collisions
We discuss fixed target and ISR inclusive photon production and attempt a
comparison between theory and experiments. The dependence of the theoretical
predictions on the structure functions, and on the renormalization and
factorization scales is investigated. The main result of this study is that the
data cannot be simultaneously fitted with a single set of scales and structure
functions. On the other hand, there is no need for an additional intrinsic
to force the agreement between QCD predictions and experiments, with
the possible exception of one data set. Since the data cover almost overlapping
kinematical ranges this raises the question of consistency among data sets. A
comparative discussion of some possible sources of experimental uncertainties
is sketched.Comment: 22 pages, 3 tables, 10 figures, Late
Medicaid spending burden among beneficiaries with treatment-resistant depression.
AIM: To evaluate Medicaid spending and healthcare resource utilization (HRU) in treatment-resistant depression (TRD).
MATERIALS & METHODS: TRD beneficiaries were identified from Medicaid claims databases (January 2010-March 2017) and matched 1:1 with major depressive disorder (MDD) beneficiaries without TRD (non-TRD-MDD) and randomly selected patients without MDD (non-MDD). Differences in HRU and per-patient-per-year costs were reported in incidence rate ratios (IRRs) and cost differences (CDs), respectively.
RESULTS: TRD beneficiaries had higher HRU than 1:1 matched non-TRD-MDD (e.g., inpatient visits: IRR = 1.41) and non-MDD beneficiaries (N = 14,710 per cohort; e.g., inpatient visits: IRR = 3.42, p \u3c 0.01). TRD beneficiaries incurred greater costs versus non-TRD-MDD (CD = US8294; p \u3c 0.05).
CONCLUSION: TRD is associated with higher HRU and costs versus non-TRD-MDD and non-MDD. TRD poses a significant burden to Medicaid
The heavy fermion damping rate puzzle
: We examine again the problem of the damping rate of a moving heavy fermion
in a hot plasma within the resummed perturbative theory of Pisarski and
Braaten. The ansatz for its evaluation which relates it to the imaginary part
of the fermion propagator pole in the framework of a self-consistent approach
is critically analyzed. As already pointed out by various authors, the only way
to define the rate is through additional implementation of magnetic screening.
We show in detail how the ansatz works in this case and where we disagree with
other authors. We conclude that the self-consistent approach is not
satisfactory.Comment: 17 page
Higher dimensional abelian Chern-Simons theories and their link invariants
The role played by Deligne-Beilinson cohomology in establishing the relation
between Chern-Simons theory and link invariants in dimensions higher than three
is investigated. Deligne-Beilinson cohomology classes provide a natural abelian
Chern-Simons action, non trivial only in dimensions , whose parameter
is quantized. The generalized Wilson -loops are observables of the
theory and their charges are quantized. The Chern-Simons action is then used to
compute invariants for links of -loops, first on closed
-manifolds through a novel geometric computation, then on
through an unconventional field theoretic computation.Comment: 40 page
Características genotípicas de Staphylococcus coagulase-negativos e taxas de cura da mastite ovina.
A mastite em ovelhas de dupla aptidão é reconhecida por afetar a qualidade do leite. Staphylococcus coagulase-negativos (SCN) são os principais micro-organismos responsáveis pela doença, e o tratamento ao final da lactação, pode contribuir para a cura e prevenção de casos subclínicos na lactação consecutiva. Entretanto, fatores de virulência e mecanismos de resistência apresentados por SCN podem reduzir as taxas de cura. Os objetivos deste trabalho foram identificar no leite de ovelhas tratadas e não tratadas à secagem com antimicrobianos, as espécies de SCN antes e após o tratamento e identificar nesses micro-organismos a presença dos genes mecA, icaA, icaC, icaD, bap, bhp, sea, seb, sec, sed e tsst-1, determinar o perfil clonal das principais espécies identificadas e relacionar os casos de cura após o tratamento com a presença/ausência dos respectivos genes. Sessenta ovelhas foram divididas em três grupos experimentais: G1, controle, metades mamárias que não receberam antimicrobiano; G2, metades mamárias em que foram administrados 10 mL de cloxacilina-benzatina 100 mg via intramamária / estrutura convencional; G3, metades mamárias em que foram administrados 86 mL de cloxacilina-benzatina 50 mg via intramamária / estrutura nanoencapsulada. As amostras de leite foram coletadas à secagem e aos 15 e 30 dias pós-parto da lactação seguinte. As análises para identificação das espécies de SCN foram realizadas por meio de testes bioquímicos e Internal Transcribe Spacer (ITS-PCR), e a pesquisa dos genes responsáveis pelos fatores de virulência e pela resistência à oxacilina foram realizados por meio da técnica de reação em cadeia de polimerase (PCR). Dentre as espécies identificadas S. warneri prevaleceram nos três grupos experimentais. Nenhuma amostra foi positiva para o gene mecA. O único gene relacionado com a produção de enterotoxinas encontrado foi o sec. Dentre os genes relacionados com a produção de biofilme, icaD foi o único identificado nos três grupos experimentais. Staphylococcus warneri, S. simulans e S. epidermidis apresentaram clones na mesma metade mamária no pré e pós-parto das ovelhas. A cloxacilina benzatina nanoparticulada 50mg / 86 mL foi eficiente para reduzir a mastite subclínica no pós-parto de ovelhas (P= 0,0192). Staphylococcus warneri, S. simulans, S. epidermidis e S. xylosus foram as espécies de maior ocorrência. Os genes icaA, icaC, icaD e bap foram encontrados no momento da desmama e no pós-parto, os genes sec e icaD estão associados à ausência de cura da mastite subclínica no pós-parto. Ovelhas em que foram isolados SCN portadores de genes responsáveis pela formação de biofilme não apresentaram resultados satisfatórios quando submetidas a esquemas de controle e ao tratamento da mastite subclínica. Os genes sec e icaD, estão associadas à ausência de cura microbiológica da mastite subclínica no pós-parto. Staphylococcus epidermidis e S. xylosus portador do gene bap estão associados à reinfecção.Orientador: Luiz Francisco Zafalon, Embrapa Pecuária Sudest
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