680 research outputs found

    Development of a bedrest muscle stress apparatus

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    In attempting further to define the deleterious effects of spaceflight on the human body, measurement systems and techniques were devised to determine the loss of skeletal muscle strength and tone as a result of spaceflight exposure. In order to determine how the muscle degradation process progresses with time during nonuse, a system for measuring muscle stress during bedrest was developed. The Bedrest Muscle Stress Apparatus is configured to slip snugly over the foot board of a standard hospital bed. Data collected with this device correlated well with pre- and post-bedrest data collected with the original skeletal muscle stress apparatus

    Germacrene D Cyclization: An Ab Initio Investigation

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    Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G*) and post Hartree-Fock (MP2/6-31G* *) ab initio methods. The calculated energies are in general agreement with experimentally observed product distributions, both from acid-catalyzed cyclizations as well as distribution of the compounds in essential oils

    Minimal Seesaw as an Ultraviolet Insensitive Cure for the Problems of Anomaly Mediation

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    We show that an intermediate scale supersymmetric left-right seesaw scenario with automatic R-parity conservation can cure the problem of tachyonic slepton masses that arises when supersymmetry is broken by anomaly mediation, while preserving ultraviolet insensitivity. The reason for this is the existence of light B - L = 2 higgses with yukawa couplings to the charged leptons. We find these theories to have distinct predictions compared to the usual mSUGRA and gauge mediated models as well as the minimal AMSB models. Such predictions include a condensed gaugino mass spectrum and possibly a correspondingly condensed sfermion spectrum.Comment: 19 pages, 1 figur

    Running with Triplets: How Slepton Masses Change With Doubly-Charged Higgses

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    We examine the slepton masses of SUSYLR models and how they change due the presence of light-doubly charged higgs bosons. We discover that the measurement of the slepton masses could bound and even predict the value of the third generation Yukawa coupling of leptons to the SU(2)_R Triplets. We also consider the unification prospects for this model with the addition of left-handed, B - L = 0 triplets--a model we call the Triplet Extended Supersymmetric Standard Model (TESSM). Finally, we discuss the changes in the slepton masses due to the presence of the SU(2)_L triplets.Comment: 20 pages, 6 figures, 4 table

    Effect of the sample geometry on the second magnetization peak in single crystalline Ba0.63_{0.63}K0.37_{0.37}BiO3_3 thick film

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    Magnetization hysteresis loop M(H)M(H) measurements performed on a single crystalline Ba0.63_{0.63}K0.37_{0.37}BiO3_3 superconducting thick film reveal pronounced sample geometry dependence of the "second magnetization peak" (SMP), i.e. a maximum in the width of M(H)M(H) occurring at the field HSMP(T)H_{\rm SMP}(T). In particular, it is found that the SMP vanishes decreasing the film dimension. We argue that the observed sample geometry dependence of the SMP cannot be accounted for by models which assume a vortex pinning enhancement as the origin of the SMP. Our results can be understood considering the thermomagnetic instability effect and/or non-uniform current distribution at H<HSMPH < H_{\rm SMP} in large enough samples.Comment: 8 pages 3 figure

    Antiprotozoal Activity of Essential Oils

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    In the present scenario of protozoal infections, new drugs are urgently needed to treat and control infections such as malaria, sleeping sickness, Chagas disease, leishmaniasis and intestinal infections, which affect millions of people each year. In this review, we are focusing on articles related to antiprotozoal essential oils extracted from plants that have been published during the last 20 years. The data analyzed indicate that essential oils could be promising antiprotozoal agents, opening perspectives to the discovery of more effective drugs of vegetal origin for the treatment of diseases caused by protozoa
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