Exploring the BWCA (Bino-Wino Co-Annihilation) Scenario for Neutralino Dark Matter

In supersymmetric models with non-universal gaugino masses, it is possible to have opposite-sign SU(2) and U(1) gaugino mass terms. In these models, the gaugino eigenstates experience little mixing so that the lightest SUSY particle remains either pure bino or pure wino. The neutralino relic density can only be brought into accord with the WMAP measured value when bino-wino co-annihilation (BWCA) acts to enhance the dark matter annihilation rate. We map out parameter space regions and mass spectra which are characteristic of the BWCA scenario. Direct and indirect dark matter detection rates are shown to be typically very low. At collider experiments, the BWCA scenario is typified by a small mass gap m_{\tilde Z_2}-m_{\tilde Z_1} ~ 20-80 GeV, so that tree level two body decays of \tilde Z_2 are not allowed. However, in this case the second lightest neutralino has an enhanced loop decay branching fraction to photons. While the photonic neutralino decay signature looks difficult to extract at the Fermilab Tevatron, it should lead to distinctive events at the CERN LHC and at a linear e^+e^- collider.Comment: 44 pages, 21 figure

Mixed Higgsino Dark Matter from a Reduced SU(3) Gaugino Mass: Consequences for Dark Matter and Collider Searches

In gravity-mediated SUSY breaking models with non-universal gaugino masses, lowering the SU(3) gaugino mass |M_3| leads to a reduction in the squark and gluino masses. Lower third generation squark masses, in turn, diminish the effect of a large top quark Yukawa coupling in the running of the higgs mass parameter m_{H_u}^2, leading to a reduction in the magnitude of the superpotential mu parameter (relative to M_1 and M_2). A low | mu | parameter gives rise to mixed higgsino dark matter (MHDM), which can efficiently annihilate in the early universe to give a dark matter relic density in accord with WMAP measurements. We explore the phenomenology of the low |M_3| scenario, and find for the case of MHDM increased rates for direct and indirect detection of neutralino dark matter relative to the mSUGRA model. The sparticle mass spectrum is characterized by relatively light gluinos, frequently with m(gl)<<m(sq). If scalar masses are large, then gluinos can be very light, with gl->Z_i+g loop decays dominating the gluino branching fraction. Top squarks can be much lighter than sbottom and first/second generation squarks. The presence of low mass higgsino-like charginos and neutralinos is expected at the CERN LHC. The small m(Z2)-m(Z1) mass gap should give rise to a visible opposite-sign/same flavor dilepton mass edge. At a TeV scale linear e^+e^- collider, the region of MHDM will mean that the entire spectrum of charginos and neutralinos are amongst the lightest sparticles, and are most likely to be produced at observable rates, allowing for a complete reconstruction of the gaugino-higgsino sector.Comment: 35 pages, including 26 EPS figure

Acute respiratory failure and CNS-depressing drugs.

Data from a drug surveillance programme were analysed to estimate the frequency with which patients with a diagnosis of respiratory failure had been exposed to CNS-depressing drugs. Eleven out of 37 patients with respiratory failure had received such medication. A detailed comparison of these patients and controls admitted to hospital because of respiratory disease who did not develop respiratory failure failed to reveal significant differences in drug usage. This unexpected finding suggests that patients with respiratory disease of equal severity may vary greatly in their tendency to develop carbon dioxide retention following administration of drugs with respiratory depressant properties

Produção de matéria seca e absorção de nutrientes pelo milho em razão da saturação por bases e da adubação potássica Dry matter yield and nutrient uptake in corn plants as a function of potassic fertilization and of basis soil saturation

O trabalho foi conduzido em condições de casa de vegetação, com o objetivo de avaliar a resposta do milho à adubação potássica e à saturação do solo por bases, na produção de matéria seca e na absorção de nutrientes. O delineamento experimental foi inteiramente casualizado, com quatro repetições, em esquema fatorial 3x2x4, constituindo-se de três solos (Areia Quartzosa, Latossolo Vermelho-Escuro e Latossolo Roxo), dois valores de saturação por bases (40% e 70 %) e quatro teores de K no solo (0,5, 1,5, 3,0 e 6,0 mmol c dm-3). Para a calagem, foi utilizada mistura de carbonato de cálcio + carbonato de magnésio (PRNT = 103,3 %) na proporção de 4:1. A adubação básica constou de 200 mg kg-1 de N, 200 mg kg-1 de P e 5 mg kg-1 de Zn por vaso de 30 L, sendo o N parcelado em 2,48 g (83,7 mg kg-1) na semeadura e o restante em duas coberturas aos 25 e 40 dias após a emergência das plântulas (DAE). As doses de K utilizadas foram de 0, 3,62, 7,24 e 14,48 g de KCl por vaso. A semeadura foi realizada em 4/3/97, utilizando-se o milho cv. Zêneca 8392, mantendo-se uma planta/vaso durante 60 DAE. O K proporciona ganhos de matéria seca até teores de 1,5 mmol c dm-3 no solo. O aumento dos teores de K no solo resultam em queda na concentração de Ca e Mg na matéria seca do milho. A elevação da saturação por bases e respectivo aumento dos teores de Ca e Mg no solo reduzem a absorção de K pelo milho.<br>The purpose of this research was to study dry matter yield and nutrients uptake by corn plants as a function of potassic fertilization and of soil basis saturation. An experiment was conducted under greenhouse conditions, using an early single hybrid corn Zêneca 8392 grown in 30 L pots, tested with three types of soil (Quartzpsamment and two alic Dark-Red Latosol - Haplorthox), with two levels of basis saturation (40 and 70 %) and four levels of potassium content (0.5, 1.5, 3.0 and 6.0 mmol c dm-3). A completely random design with four replications was utilized. The basis saturation treatments were calibrated by liming the soils with a mixture of 4:1 of calcium and magnesium carbonate, according to soil type. K content in the soil was established by applying 0, 3.62, 7.24 and 14.48 g of KCl per 30 L pot. P (200 mg kg-1) and Zn (5 mg kg-1) were applied to all treatments at sowing time. N was applied at sowing time (83.7 mg kg-1) as well as at top dressing, 25 and 40 days after seedling emergence, totalizing 200 mg kg-1. Sixty days after seedling emergence the dry matter weight and N, P, K, Ca and Mg content of the leaves and stems were determined. The dry matter yield was increased by K concentrations in the soil up to 1.5 mmol c dm-3. The increase in soil K levels allowed decrease on the Ca and Mg concentrations in corn dry matter. The increase of basis saturation and soil Ca and Mg levels decrease corn plant K uptake