Naturally enhanced ion-line spectra around the equatorial 150-km region

For many years strong radar echoes coming from 140–170 km altitudes at low latitudes have been associated to the existence of field-aligned irregularities (FAIs) (the so called 150-km echoes). In this work, we present frequency spectra as well as angular distribution of 150-km echoes. When the 150-km region is observed with beams perpendicular to the magnetic field (<B>B</B>) the observed radar spectra are very narrow with spectral widths between 3–12 m/s. On the other hand, when few-degrees off-perpendicular beams are used, the radar spectra are wide with spectral widths comparable to those expected from ion-acoustic waves at these altitudes (>1000 m/s). Moreover the off-perpendicular spectral width increases with increasing altitude. The strength of the received echoes is one to two orders of magnitude stronger than the expected level of waves in thermal equilibrium at these altitudes. Such enhancement is not due to an increase in electron density. Except for the enhancement in power, the spectra characteristics of off-perpendicular and perpendicular echoes are in reasonable agreement with expected incoherent scatter spectra at these angles and altitudes. 150-km echoes are usually observed in narrow layers (2 to 5). Bistatic common volume observations as well as observations made few kilometers apart show that, for most of the layers, there is very high correlation on power fluctuations without a noticeable time separation between simultaneous echoes observed with Off-perpendicular and Perpendicular beams. However, in one of the central layers, the echoes are the strongest in the perpendicular beam and absent or very weak in the off-perpendicular beams, suggesting that they are generated by a plasma instability. Our results indicate that most echoes around 150-km region are not as aspect sensitive as originally thought, and they come from waves that have been enhanced above waves in thermal equilibrium

Renormalized coordinate approach to the thermalization process

We consider a particle in the harmonic approximation coupled linearly to an environment. modeled by an infinite set of harmonic oscillators. The system (particle--environment) is considered in a cavity at thermal equilibrium. We employ the recently introduced notion of renormalized coordinates to investigate the time evolution of the particle occupation number. For comparison we first present this study in bare coordinates. For a long ellapsed time, in both approaches, the occupation number of the particle becomes independent of its initial value. The value of ocupation number of the particle is the physically expected one at the given temperature. So we have a Markovian process, describing the particle thermalization with the environment. With renormalized coordinates no renormalization procedure is required, leading directly to a finite result.Comment: 16 pages, LATEX, 2 figure

Які соціально-економічні наслідки матиме скасування мораторію на продаж земель сільськогосподарського призначення в Україні?

This study investigated the long-term effects of total and partial replacement of dietary fish meal (FM) by a mixture of agricultural products on sperm quality of African catfish Clarias gariepinus. Four isonitrogenous and isoenergetic diets were formulated containing graded levels of either 50% FM and maize meal (diet 1); 25% FM mixed with crude sunflower oil cake (SFOC) and bean meal (BM) (diet 2); 12.5% FM mixed with sunflower oil cake, BM and ground nut oil cake (GOC) (diet 3) and 0% FM mixed with de-hulled sunflower oil cake (SFOCD), BM and ground nut oil cake (diet 4). Gonadosomatic index (GSI), sperm quality, plasma sex steroids (11-keto testosterone [11-KT]; testosterone [T]; estradiol-17beta [E2]) were evaluated on 10 to 24 fish fed on each diet. Sperm quality was assessed using computer-assisted sperm analysis (CASA). Total replacement of fish meal by plant products markedly increased sperm volume, spermatocrit, spermatozoa integrity, and sperm motility. Fish fed diet 3 (12.5% fish meal) provided intermediate results on sperm quality whereas the lowest values were obtained in fish fed diets 1 and 2. In fish fed 0% fish meal (diet 4), androgen levels were higher and estrogen levels were lower than in fish fed fish meal diets. Based on dietary lipid and fatty acid analyses, these results suggest a positive impact of short chain n-6 fatty acids on androgen synthesis and sperm quality. In conclusion, a combination of ground nut oil cake, bean meal and sunflower oil cake (preferably when the sunflower is dehulled) in African catfish diet improves the sperm quality

Expression of iron-related genes in human brain and brain tumors

<p>Abstract</p> <p>Background</p> <p>Defective iron homeostasis may be involved in the development of some diseases within the central nervous system. Although the expression of genes involved in normal iron balance has been intensively studied in other tissues, little is known about their expression in the brain. We investigated the mRNA levels of hepcidin (<it>HAMP</it>), HFE, neogenin (<it>NEO1</it>), transferrin receptor 1 (<it>TFRC</it>), transferrin receptor 2 (<it>TFR2</it>), and hemojuvelin (<it>HFE2</it>) in normal human brain, brain tumors, and astrocytoma cell lines. The specimens included 5 normal brain tissue samples, 4 meningiomas, one medulloblastoma, 3 oligodendrocytic gliomas, 2 oligoastrocytic gliomas, 8 astrocytic gliomas, and 3 astrocytoma cell lines.</p> <p>Results</p> <p>Except for hemojuvelin, all genes studied had detectable levels of mRNA. In most tumor types, the pattern of gene expression was diverse. Notable findings include high expression of transferrin receptor 1 in the hippocampus and medulla oblongata compared to other brain regions, low expression of HFE in normal brain with elevated HFE expression in meningiomas, and absence of hepcidin mRNA in astrocytoma cell lines despite expression in normal brain and tumor specimens.</p> <p>Conclusion</p> <p>These results indicate that several iron-related genes are expressed in normal brain, and that their expression may be dysregulated in brain tumors.</p

A fruit diet rather than invertebrate diet maintains a robust innate immunity in an omnivorous tropical songbird

Experiments were funded by the Royal Netherlands Academy of Arts and Sciences (KNAW) Academy Ecology Fund to C.J.N—(KENMERK J1618/ECO/G437). C.J.N. was supported by a studentship funded by the Leventis Conservation Foundation through the University of St. Andrews UK and an Ubbo Emmius grant of the University of Groningen, The Netherlands. B.I.T. was supported by the Netherlands Organisation for Scientific Research (NWO‐Vidi 864.10.012).1. Diet alteration may lead to nutrient limitations even in the absence of food limitation, and this may affect physiological functions, including immunity. Nutrient limitations may also affect the maintenance of body mass and key life history events that may affect immune function. Yet, variation in immune function is largely attributed to energetic trade-offs rather than specific nutrient constraints. 2. To test the effect of diet on life history traits, we tested how diet composition affects innate immune function, body mass and moult separately and in combination with each other, and then used path analyses to generate hypotheses about the mechanistic connections between immunity and body mass under different diet composition. 3. We performed a balanced parallel and crossover design experiment with omnivorous common bulbuls Pycnonotus barbatus in out-door aviaries in Nigeria. We fed 40 wild-caught bulbuls ad libitum on fruits or invertebrates for 24 weeks, switching half of each group between treatments after 12 weeks. We assessed innate immune indices (haptoglobin, nitric oxide and ovotransferrin concentrations, and haemagglutination and haemolysis titres), body mass and primary moult, fortnightly. We simplified immune indices into three principal components (PCs), but we explored mechanistic connections between diet, body mass and each immune index separately. 4. Fruit fed bulbuls had higher body mass, earlier moult and showed higher values for two of the three immune PCs compared to invertebrate fed bulbuls. These effects were reversed when we switched bulbuls between treatments after 12 weeks. Exploring the correlations between immune function, body mass and moult, showed that an increase in immune function was associated with a decrease in body mass and delayed moult in invertebrate fed bulbuls, while fruit fed bulbuls maintained body mass despite variation in immune function. Path analyses indicated that diet composition was most likely to affect body mass and immune indices directly and independently from each other. Only haptoglobin concentration was indirectly linked to diet composition via body mass. 5. We demonstrated a causal effect of diet composition on innate immune function, body mass and moult: bulbuls were in better condition when fed on fruits than invertebrates, confirming that innate immunity is nutrient specific. Our results are unique because they show a reversible effect of diet composition on wild adult birds whose immune systems are presumably fully developed and adapted to wild conditions – demonstrating a short-term consequence of diet alteration on life history traits.Publisher PDFPeer reviewe

Equatorial 150 km echoes and daytime F region vertical plasma drifts in the Brazilian longitude sector

Previous studies showed that conventional coherent backscatter radar measurements of the Doppler velocity of the so-called 150 km echoes can provide an alternative way of estimating ionospheric vertical plasma drifts during daytime hours (Kudeki and Fawcett, 1993; Chau and Woodman, 2004). Using observations made by a small, low-power 30 MHz coherent backscatter radar located in the equatorial site of São Luís (2.59° S, 44.21° W; −2.35° dip lat), we were able to detect and monitor the occurrence of 150 km echoes in the Brazilian sector. Using these measurements we estimated the local time variation of daytime vertical ionospheric drifts in the eastern American sector. Here, we present a few interesting cases of 150 km-echoes observations made by the São Luís radar and estimates of the diurnal variation of vertical drifts. These cases exemplify the variability of the vertical drifts in the Brazilian sector. Using same-day 150 km-echoes measurements made at the Jicamarca Radio Observatory in Peru, we also demonstrate the variability of the equatorial vertical drifts across the American sector. In addition to first estimates of the absolute vertical plasma drifts in the eastern American (Brazilian) sector, we also present observations of abnormal drifts detected by the São Luís radar associated with the 2009 major sudden stratospheric warming event

Baseline data of four insecticides with different modes of action for Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

La mosca de la fruta del Mediterráneo, Ceratitis capitata (Wiedemann), y la mosca sudamericana de los frutos, Anastrepha fraterculus (Wiedemann) son plagas de gran importancia económica en Argentina y el mundo. Una de las formas de control es el uso de insecticidas en pulverizaciones totales o en cebos. El uso reiterado de un determinado producto ejerce una fuerte presión de selección, pudiendo ocasionar la aparición de resistencia. El objetivo de este trabajo fue determinar el dato de nivel básico de cuatro insecticidas con diferentes mecanismos de acción mediante bioensayos en laboratorio. Los productos utilizados fueron formulaciones comerciales de ciantraniliprol, clorpirifos, lambdacialotrina y spinosad. La concentración letal media se estimó mediante un análisis de la curva dosis-respuesta. Para ciantraniliprol y clorpirifós los machos y las hembras de ambas especies fueron igualmente susceptibles. Para lambdacialotrina se detectaron diferencias entre las dos especies; la CL50 de A. fraterculus (0,058 y 0,074 para machos y hembras respectivamente) fue menor que la de C. capitata (0,523 y 0,624 para machos y hembras respectivamente). Para spinosad, los machos de A. fraterculus fueron igualmente susceptibles que los machos y las hembras de C. capitata. Estos resultados generan valores de referencia para Argentina y evidencian la necesidad de completar este tipo de estudios con evaluaciones de poblaciones naturales sobre las cuales se ejerce control químico así como con ensayos en campo y semi-campo. Asimismo muestran la necesidad de completar este tipo de estudios con evaluaciones de los niveles de ingesta en las distintas concentraciones.The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the South American fruit fly, Anastrepha fraterculus (Wiedemann) are pests of major economic importance in Argentina and worldwide. One way to control them is the use of insecticide in sprays or baits. The repeated use of a particular product exerts a strong selection pressure and can lead to development of resistance. The aim of this study was to determine baseline data of four insecticides with different mechanisms of action through laboratory bioassays. The products used were commercial formulations of cyantraniliprole, chlorpyrifos, lambdacyalothrin and spinosad. The mean lethal concentration was estimated by a dose-response curve analysis. Cyantraniliprole and chlorpyrifos were equally susceptible for males and females of both species. For lambdacyalothrin differences between the two species were detected; LC50 of A. fraterculus (0.058 and 0.074 for males and females respectively) was lower than that of C. capitata (0.523 and 0.624 for males and females respectively). For spinosad, A. fraterculus males were equally susceptible than males and females of C. capitata. These results generate reference values for Argentina and demonstrate the need to complete these studies with field evaluations of natural populations on which chemical control is exercised as well as with field and semi-field trials. It also shows the need to complete these studies in which the intake at different concentrations is measured.Fil: Paez Jerez, P. G.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Carrizo, B. N.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Musse, R.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Varela, E.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Armiñana, A.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Milla, F.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Vera, Maria Teresa. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de la Vega, M. H.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; Argentin