Mapping of static magnetic fields near the surface of mobile phones

Whether the use of mobile phones (MP) represents a health hazard is still under debate. As part of the attempts to resolve this uncertainty, there has been an extensive characterization of the electromagnetic fields MP emit and receive. While the radiofrequencies (RF) have been studied exhaustively, the static magnetic fields (SMF) have received much less attention, regardless of the fact there is a wealth of evidence demonstrating their biological effects. We performed 2D maps of the SMF at several distances from the screen of 5 MP (models between 2013 and 2018) using a tri-axis magnetometer. We built a mathematical model to fit our measurements, extrapolated them down to the phones’ screen, and calculated the SMF on the skin of a 3D head model, showing that exposure is in the µT to mT range. Our literature survey prompts the need of further research not only on the biological effects of SMF and their gradients, but also on their combination with extremely low frequency (ELF) and RF fields. The study of combined fields (SMF, ELF, and RF) as similar as possible to the ones that occur in reality should provide a more sensible assessment of potential risks.Fil: Zastko, L.. Cancer Research Institute Of Slovak Academy Of Sciences; EslovaquiaFil: Makinistian, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Tvarozná, A.. Cancer Research Institute Of Slovak Academy Of Sciences; EslovaquiaFil: Ferreyra, F. L.. Universidad Nacional de San Luis; ArgentinaFil: Belyaev, I.. Cancer Research Institute Of Slovak Academy Of Sciences; Eslovaqui

NIDIFICACIÓN DE LA LECHUCITA CANELA (AEGOLIUS HARRISII) EN MISIONES, ARGENTINA

Resumen ∙ Aunque el conocimiento de la distribución de la Lechucita Canela (Aegolius harrisii) se amplió notablemente en la última década, su biología permanece poco conocida. El conocimiento de la nidificación se basa en un solo nido confirmado, que no fue monitoreado, y una serie de observaciones de posibles nidos donde no fue comprobada la presencia de huevos o pichones. Entre diciembre de 2018 y enero de 2019, confirmamos y estudiamos un nido en una vieja cavidad excavada por una pareja de Carpintero Garganta Estriada (Dryocopus lineatus) a 9,6 m de altura en una grapia (Apuleia leiocarpa) muerta en selva Atlántica primaria del Parque Provincial Cruce Caballero, Misiones, Argentina. El nido contenía tres huevos blancos que eclosionaron en días alternos. Durante la incubación encontramos abundantes restos de escarabajos (Scarabaeidae: Coleoptera) debajo de la entrada del nido. Al nacer, los pichones tenían plumón natal gris oscuro muy ralo; a los 10 días empezaban a tener disco facial como el de los adultos; y a los 24 días se asemejaban a los adultos. Un adulto pasó todo el día dentro del nido desde la incubación hasta que el pichón mayor tenía 20–24 días de edad. Desde que nació el primer pichón hasta que voló el último los adultos trajeron por lo menos 32 roedores pequeños. Hubo un pico de aportes de alimentación justo después de la puesta del sol. Los tres pichones volaron exitosamente luego de 35–37 días, lo cual está en el límite superior del rango conocido para el Mochuelo Boreal (A. funereus) y el Mochuelo Cabezón (A. acadicus). No volvieron a utilizar la cavidad una vez que voló el último pichón. Aún es importante esclarecer el período de incubación, el rol de cada sexo en la reproducción y el rol de las cavidades (e.g., como dormidero) fuera del ciclo reproductivo. Abstract ∙ Nesting of the Buff-fronted Owl (Aegolius harrisii) in Misiones, Argentina Knowledge of the distribution of the Buff-fronted Owl (Aegolius harrisii) has increased notably in the last decade, but its biology remains poorly known. Knowledge of nesting is based on one confirmed nest, which was not monitored, and a series of observations of possible nests where the presence of eggs or nestlings was not confirmed. Between December 2018 and January 2019, we confirmed and studied a nest in an old cavity excavated by Lineated Woodpeckers (Dryocopus lineatus), 9.6 m above the ground in a dead garapa (Apuleia leiocarpa) tree, in primary Atlantic Forest at Parque Provincial Cruce Caballero, Misiones, Argentina. The nest contained three white eggs that hatched on alternate days. During incubation we found abundant beetle (Scarabaeidae: Coleoptera) remains below the nest entrance. On hatching, nestlings had sparse dark grey down; at 10 days old they began to have a facial disk like the adults; and by 24 days they looked similar to adults. One adult roosted in the nest all day from incubation until the oldest nestling reached 20–24 days of age. From when the first nestling hatched until the last nestling fledged, the adults brought at least 32 small rodents to the nest. There was a peak in prey delivery just after sunset. The three nestlings fledged successfully 35 to 37 days after hatching, which is at the high end of the range reported for Boreal (A. funereus) and Northern Saw-whet Owl (A. acadicus). They did not return to use the cavity once the last nestling had fledged. Further study is required to clarify the incubation period, the role of each sex in reproduction, and the role of cavities (e.g., for roosting) outside of the breeding cycle

Estabilidade de agregados em solos sódicos e salino-sódicos.

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Insights into in vivo adipocyte differentiation through cell-specific labeling in zebrafish.

White adipose tissue hyperplasia has been shown to be crucial for handling excess energy in healthy ways. Though adipogenesis mechanisms have been underscored in vitro, we lack information on how tissue and systemic factors influence the differentiation of new adipocytes. While this could be studied in zebrafish, adipocyte identification currently relies on neutral lipid labeling, thus precluding access to cells in early stages of differentiation. Here we report the generation and analysis of a zebrafish line with the transgene fabp4a(- 2.7):EGFPcaax. In vivo confocal microscopy of the pancreatic and abdominal visceral depots of transgenic larvae, revealed the presence of labeled mature adipocytes as well as immature cells in earlier stages of differentiation. Through co-labeling for blood vessels, we observed a close interaction of differentiating adipocytes with endothelial cells through cell protrusions. Finally, we implemented hyperspectral imaging and spectral phasor analysis in Nile Red-labeled transgenic larvae and revealed the lipid metabolic transition towards neutral lipid accumulation of differentiating adipocytes. Altogether our work presents the characterization of a novel adipocyte-specific label in zebrafish and uncovers previously unknown aspects of in vivo adipogenesis.Agencia Nacional de Investigación e InnovaciónPrograma de Desarrollo de las Ciencias BásicasFondo de Convergencia Estructural del Mercosu

NESTING AND SOCIAL ROOSTING OF THE OCHRE-COLLARED PICULET (PICUMNUS TEMMINCKII) AND WHITE-BARRED PICULET (PICUMNUS CIRRATUS), AND IMPLICATIONS FOR THE EVOLUTION OF WOODPECKER (PICIDAE) BREEDING BIOLOGY

To understand the evolution of reproductive strategies and social behavior in woodpeckers (Picidae), it is useful to compare breeding biology between the two largest subfamilies: Picinae (true woodpeckers) and Picumninae (piculets). The piculets include four species in the Old World (Sasia, Verreauxia, and Picumnus spp.) and a recent radiation of 25 Picumnus spp. in the Neotropics; however, information about their breeding biology is limited. We studied four nests and one roost of the Ochre-collared Piculet (Picumnus temminckii) in the Atlantic Forest of Misiones and eight nests of the White-barred Piculet (Picumnus cirratus) in the Chaco region, of Argentina, and reviewed the published literature on other species of Picumnus. Cavities were excavated in dead branches and tree trunks. Entrance diameters were 2.2 ± 0.2 cm (mean ± SE) for the Ochre-collared Piculet and 2.5 ± 0.1 cm for the White-barred Piculet. In both species, both parents excavated cavities, incubated eggs, fed nestlings, and maintained the cavity clean of feces. In the Ochre-collared Piculet, incubation lasted 13 days, on-bouts were 42 ± 4 (± SE) min for females and 48 ± 7 min for males, and nest attentiveness was nearly 100% during incubation and the first 10 days after hatching. Nestling Ochre-collared Piculets hatched without feathers, their eyes and pin feathers opened on day 13, and they fledged on days 26 and 27. Nestlings of both species were fed ant larvae and other small prey. In Ochre-collared Piculets, the rate of food delivery (especially by the female) increased with nestling age. Females removed 71% and males 29% of fecal sacs. Fledgling Picumnus have dark crowns and look like adult females, which is different from Sasia, Verreauxia, and most Picinae. Unlike Picinae, Picumnus parents roost together in their nest cavity before laying, throughout nesting, and (accompanied by their offspring) after fledging. They also roost in pairs or groups when not breeding. If Old World piculets also roost socially, this trait may reflect an ancestral condition of the woodpeckers

Field-tuned order by disorder in frustrated Ising magnets with antiferromagnetic interactions

We demonstrate the appearance of thermal order by disorder in Ising pyrochlores with staggered antiferromagnetic order frustrated by an applied magnetic field. We use a mean-field cluster variational method, a low-temperature expansion, and Monte Carlo simulations to characterize the order-by-disorder transition. By direct evaluation of the density of states, we quantitatively show how a symmetry-broken state is selected by thermal excitations. We discuss the relevance of our results to experiments in 2D and 3D samples and evaluate how anomalous finite-size effects could be exploited to detect this phenomenon experimentally in two-dimensional artificial systems, or in antiferromagnetic all-in-all-out pyrochlores like Nd2Hf2O7 or Nd2Zr2O7, for the first time.Publisher PDFPeer reviewe

Field-tuned order by disorder in frustrated ising magnets with antiferromagnetic interactions

We demonstrate the appearance of thermal order by disorder in Ising pyrochlores with staggered antiferromagnetic order frustrated by an applied magnetic field. We use a mean-field cluster variational method, a low-temperature expansion, and Monte Carlo simulations to characterize the order-by-disorder transition. By direct evaluation of the density of states, we quantitatively show how a symmetry-broken state is selected by thermal excitations. We discuss the relevance of our results to experiments in 2D and 3D samples and evaluate how anomalous finite-size effects could be exploited to detect this phenomenon experimentally in two-dimensional artificial systems, or in antiferromagnetic all-in-all-out pyrochlores like Nd2Hf2O7 or Nd2Zr2O7, for the first time.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico