Dielectric Function of Diluted Magnetic Semiconductors in the Infrared Regime

We present a study of the dielectric function of metallic (III,Mn)V diluted magnetic semiconductors in the infrared regime. Our theoretical approach is based on the kinetic exchange model for carrier induced (III,Mn)V ferromagnetism. The dielectric function is calculated within the random phase approximation and, within this metallic regime, we treat disorder effects perturbatively and thermal effects within the mean field approximation. We also discuss the implications of this calculations on carrier concentration measurements from the optical f-sum rule and the analysis of plasmon-phonon coupled modes in Raman spectra.Comment: 6 pages, 6 figures include

μ→eγ\mu\to e\gamma Decay in the Left-Right Supersymmetric Model

We calculate the rate of the decay $\mu \to e\gamma$ and the electric dipole moment of the electron in the left-right supersymmetric model when the breaking of parity occurs at a considerably large scale. The low-energy flavor violation in the model originates either from the nonvanishing remnants of the left-right symmetry in the slepton mass matrix or from the direct flavor changing lepton-slepton-neutralino interaction. The result is found to be large for the masses of the supersymmetric particles not far from the electroweak scale and already accessible at the current experimental accuracy. It also provides nontrivial constraints of the lepton mixing in the model.Comment: 10 pages, LaTeX, 1 figur

Estimating novel potential drug targets of Plasmodium falciparum by analysing the metabolic network of knock-out strains in silico

Malaria is one of the world’s most common and serious diseases causing death of about 3 million people each year. Its most severe occurrence is caused by the protozoan Plasmodium falciparum. Biomedical research could enable treating the disease by effectively and specifically targeting essential enzymes of this parasite. However, the parasite has developed resistance to existing drugsmaking it indispensable to discover new drugs. We have established a simple computational tool which analyses the topology of the metabolic network of P. falciparum to identify essential enzymes as possible drug targets.Weinvestigated the essentiality of a reaction in the metabolic network by deleting (knocking-out) such a reaction in silico. The algorithmselected neighbouring compounds of the investigated reaction that had to be produced by alternative biochemical pathways. Using breadth first searches, we tested qualitatively if these products could be generated by reactions that serve as potential deviations of the metabolic flux. With this we identified 70 essential reactions. Our results were compared with a comprehensive list of 38 targets of approved malaria drugs. When combining our approach with an in silico analysis performed recently [Yeh, I., Hanekamp, T., Tsoka, S., Karp, P.D., Altman, R.B., 2004. Computational analysis of Plasmodium falciparum metabolism: organizing genomic information to facilitate drug discovery. Genome Res. 14, 917–924] we could improve the precision of the prediction results. Finally we present a refined list of 22 new potential candidate targets for P. falciparum, half of which have reasonable evidence to be valid targets against micro-organisms and cancer

Simplified Triceps Surae Muscle Volume Assessment in Older Adults

Triceps surae (TS) muscle volume can be estimated in young adults by only considering the maximal anatomical cross-sectional area (ACSAmax) and the length of the muscle due to the presence of a constant muscle-specific shape factor. This study aimed to investigate if this simplified muscle volume assessment is also applicable in older adults or if muscle-specific shape changes with aging. MRI sequences were taken from the dominant leg of 21 older female adults. The boundaries of all three TS muscles (SOL, soleus; GM, gastrocnemius medialis; GL, gastrocnemius lateralis) were manually outlined in transverse image sequences, and muscle volume for each muscle was calculated as the integral of the obtained cross-sectional areas of the contours along the whole length of the muscle (measured volume) and, in addition, by using the average muscle-specific shape factors of each muscle obtained from the ratio of the measured volume and the product of ACSAmax and the muscle length (estimated volume). There were no differences in the measured and estimated muscle volumes (SOL: 357.7 ± 61.8 vs. 358.8 ± 65.3 cm3; GM: 179.5 ± 32.8 vs. 179.8 ± 33.3 cm3; GL: 90.2 ± 15.9 vs. 90.4 ± 14.8 cm3). However, when using the reported shape factors of younger adults instead, we found a significant (p < 0.05) overestimation of muscle volume for SOL and GM with average RMS differences of 6.1 and 7.6%, respectively. These results indicate that corrections of muscle-specific shape factors are needed when using the previously proposed simplified muscle volume assessment as aging may not only be accompanied with muscle atrophy but also changes in the shape of skeletal muscle

IgE-Mediated Hypersensitivity Reactions to Cannabis in Laboratory Personnel

Background: There have been sporadic reports of hypersensitivity reactions to plants of the Cannabinaceae family (hemp and hops), but it has remained unclear whether these reactions are immunologic or nonimmunologic in nature. Objective: We examined the IgE-binding and histamine-releasing properties of hashish and marijuana extracts by CAP-FEIA and a basophil histamine release test. Methods: Two workers at a forensic laboratory suffered from nasal congestion, rbinitis, sneezing and asthmatic symptoms upon occupational contact with hashish or marijuana, which they had handled frequently for 25 and 16 years, respectively. Neither patient had a history of atopic disease. Serum was analyzed for specific IgE antibodies to hashish or marijuana extract by research prototype ImmunoCAP, and histamine release from basophils upon exposure to hashish or marijuana extracts was assessed. Results were matched to those of 4 nonatopic and 10 atopic control subjects with no known history of recreational or occupational exposure to marijuana or hashish. Results: Patient 1 had specific IgE to both hashish and marijuana (CAP class 2), and patient 2 to marijuana only (CAP class 2). Controls proved negative for specific IgE except for 2 atopic individuals with CAP class 1 to marijuana and 1 other atopic individual with CAP class 1 to hashish. Stimulation of basophils with hashish or marijuana extracts elicited histamine release from basophils of both patients and 4 atopic control subjects. Conclusions: Our results suggest an IgE-related pathomechanism for hypersensitivity reactions to marijuana or hashish. Copyright (C) 2011 S. Karger AG, Base

Populações de plantas e estratégias de manejo de irrigação na cultura da soja.

Este trabalho teve por objetivo verificar o efeito do manejo da irrigação e da população de plantas sobre o rendimento de grãos em soja semeada após a época recomenda. O experimento foi conduzido de janeiro a maio de 2005 na Universidade Federal de Santa Maria. O delineamento experimental utilizado foi blocos ao acaso com parcelas subdivididas e quatro repetições. Nas parcelas principais foram distribuídos três manejos de irrigação: 1) não-irrigado; 2) irrigado todo o ciclo; e 3) irrigado nos períodos críticos. Nas subparcelas foram distribuídas duas populações de plantas (250.000 e 400.000 plantas ha-1). Para as plantas irrigadas todo o ciclo ou somente nos períodos críticos, o rendimento de grãos não diferiu entre as populações testadas. O rendimento de grãos das plantas não-irrigadas teve um incremento de 21% com o aumento da população de plantas para 400.000 plantas ha-1

Seasonality in Major Depressive Disorder: Effect of Sex and Age

Background: Aside from the concept of seasonal affective disorder, the evidence for a seasonal pattern (SP) of major depressive disorder (MDD) is controversial. Furthermore, the effect of sex and age is still unclear. Methods: This is a nationwide, registry-based study assessing all inpatient admissions in mental health hospitals due to MDD episodes according to ICD-10 (moderate (F32/33.1), severe (F32/33.2) and severe with psychotic features (F32/33.3)) in Austria across 14 years. Calculations were based on deviations from expected monthly admissions. Results: The sample comprised 231,824 hospitalisations (36.8% men) for MDD. A significant SP (p=0.001) in moderate and severe depressive episodes in both women and men with decreased admission rates in the summer months and December was detected. In psychotic depression a significant SP was only evidenced in women (p = 0.002, men: p = 0.291). Patients older than 55 years had a reduced SP compared to those being younger. Limitations: Only anonymised admission data of inpatient treatments were available. Hospitalization rates cannot fully be equated to the occurrence of MDD. Conclusions: The current study indicates a seasonal variation in MDD symptoms that may go beyond seasonal affective disorder. Knowledge about the predictability of depressive symptoms in patients should encourage preventive strategies

Thermal Re-emission Model

Starting from a continuum description, we study the non-equilibrium roughening of a thermal re-emission model for etching in one and two spatial dimensions. Using standard analytical techniques, we map our problem to a generalized version of an earlier non-local KPZ (Kardar-Parisi-Zhang) model. In 2+1 dimensions, the values of the roughness and the dynamic exponents calculated from our theory go like $\alpha \approx z \approx 1$ and in 1+1 dimensions, the exponents resemble the KPZ values for low vapor pressure, supporting experimental results. Interestingly, Galilean invariance is maintained althrough.Comment: 4 pages, minor textual corrections and typos, accepted in Physical Review B (rapid

Composite Spin Waves, Quasi-Particles and Low Temperature resistivity in Double Exchange Systems

We make a quantum description of the electron low temperature properties of double exchange materials. In these systems there is a strong coupling between the core spin and the carriers spin. This large coupling makes the low energy spin waves to be a combination of ion and electron density spin waves. We study the form and dispersion of these composite spin wave excitations. We also analyze the spin up and down spectral functions of the temperature dependent quasi-particles of this system. Finally we obtain that the thermally activated composite spin waves renormalize the carriers effective mass and this gives rise to a low temperature resistivity scaling as T ^{5/2}.Comment: 4 pages, REVTE