Spin inversion devices with Fano anti-resonances

Analyzing spin transport of quasi-2D electrons gas moving through a semiconductor wave guide subject to a sectionally homogeneous tilted magnetic field, we found well-defined selection rules for resonant and antiresonant spin carrier transmission. Based on these selection rules and the band shift induced by the magnetic field strength and the tilting angles, we propose an efficient spin inversion device. For a polarized incoming electron beam, we can determine from our theoretical approach, physical conditions for spin-inversion efficiency up to 80%. We visualize this mechanism in terms of conductance and the spacial behavior of the wave function amplitude along the superlattice.Comment: 3 pages, 3 figures, regular pape

Denitrification-derived nitric oxide modulates biofilm formation in Azospirillum brasilense

Azospirillum brasilense is a rhizobacterium that provides beneficial effects on plants when they colonize roots. The formation of complex bacterial communities known as biofilms begins with the interaction of planktonic cells with surfaces in response to appropriate signals. Nitric oxide (NO) is a signaling molecule implicated in numerous processes in bacteria, including biofilm formation or dispersion, depending on genera and lifestyle. Azospirillum brasilense Sp245 produces NO by denitrification having a role in root growth promotion. We analyzed the role of endogenously produced NO on biofilm formation in A. brasilense Sp245 and in a periplasmic nitrate reductase mutant (napA::Tn5; Faj164) affected in NO production. Cells were statically grown in media with nitrate or ammonium as nitrogen sources and examined for biofilm formation using crystal violet and by confocal laser microscopy. Both strains formed bio- films, but the mutant produced less than half compared with the wild type in nitrate medium showing impaired nitrite production in this condition. NO measurements in biofilm confirmed lower values in the mutant strain. The addition of a NO donor showed that NO influences biofilm formation in a dose-dependent manner and reverses the mutant phenotype, indicating that Nap positively regulates the formation of biofilm in A. brasilense Sp245.Fil: Arruebarrena Di Palma, Andrés. Universidad Nacional de Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pereyra, Cintia Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Moreno Ramírez, Lizbeth. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Xiqui Vazquez, Maria L.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Baca, Beatriz E.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Pereyra, María Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lamattina, Lamattina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Creus, Cecilia Mónica. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Additional Data and Perspectives on Interspecific Aggression in the Common Loon, Gavia immer

We witnessed the killing of a female Redhead (Aythya Americana) by a male Common Loon (Gavia immer). The wound was delivered into the abdomen from below, and death occurred because of a torn, hemorrhaging liver. This same Common Loon also threatened a female Ring-necked Duck (Aythya collaris) with ducklings. We hypothesize that interspecific aggression by loons might be energetically costly but is sometimes adaptive because it deters predators

Egg Predation at a Golden Eagle, Aquila chrysaetos, Nest

We observed an egg being taken from a Golden Eagle nest near Atlin, British Columbia, by a Common Raven. This is apparently the first record of its kind

Prolonging Kidney Graft Survival with Concanavalin A: Effects of temperature, perfusate composition, pH, and different manufacturing lots

This study analyzes the effect of temperature, perfusate composition, pH, and variable manufacturing lots in prolonging kidney allograft survival with Concanavalin A (Con A). Cold temperature (4°C), crystalloid composition of the perfusates, and neutral or mildly alkaline pH were important factors in the effect of Con A on prolonging allograft survival. Also, different lots of Con A from the same manufacturer produced variable results in prolonging survival. Thus, multiple factors should be considered if Con A is to be used to prolong kidney allograft survival

'Tannat' (Vitis vinifera L.) as a model of responses to climate variability

Climate variability influence on the vine is widely studied for its impact on grape final composition and quality. During 1994-2016, thermal and water regimes and their influence on grapevine yield, sanitary status and berry composition were analyzed for 'Tannat' grown in commercial vineyards in the south of Uruguay (Lat 34° 37' S; 56° 17' W). Statistical analysis showed that the principal component analysis (PCA) separated years in three groups: Group 1: rainfall over the growing season higher than the average, limited sanitary status, acidity and yield higher than average, lower sugar content, late harvest. Group 2: greater thermal conditions and water component lower than average, better sanitary status, sugar contents and acidity lower than average, early harvest. Group 3: thermal conditions lower than average, rainfall higher during budbreak-fruitset period and lower than average in the month before harvest, berry size and sugar contents greater than average. Correlations between climate, yield and berry quality variables were established and stages of greater sensitivity to these climate elements were determined. In the studied years, climate variability within the region was high and 'Tannat' showed to be strongly influenced by such variability