24 research outputs found
Large enhancement of deuteron polarization with frequency modulated microwaves
We report a large enhancement of 1.7 in deuteron polarization up to values of
0.6 due to frequency modulation of the polarizing microwaves in a two liters
polarized target using the method of dynamic nuclear polarization. This target
was used during a deep inelastic polarized muon-deuteron scattering experiment
at CERN. Measurements of the electron paramagnetic resonance absorption spectra
show that frequency modulation gives rise to additional microwave absorption in
the spectral wings. Although these results are not understood theoretically,
they may provide a useful testing ground for the deeper understanding of
dynamic nuclear polarization.Comment: 10 pages, including the figures coming in uuencoded compressed tar
files in poltar.uu, which also brings cernart.sty and crna12.sty files neede
Spatial variability of leaf wetness duration in cotton, coffee and banana crop canopies
Cross-species models of attention-deficit/hyperactivity disorder and autism spectrum disorder: lessons from CNTNAP2, ADGRL3, and PARK2
Animal and cellular models are essential tools for all areas of biological research including neuroscience. Model systems can also be used to investigate the pathophysiology of psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). In this review, we provide a summary of animal and cellular models for three genes linked to ADHD and ASD in human patients - CNTNAP2, ADGRL3, and PARK2. We also highlight the strengths and weaknesses of each model system. By bringing together behavioral and neurobiological data, we demonstrate how a cross-species approach can provide integrated insights into gene function and the pathogenesis of ADHD and ASD. The knowledge gained from transgenic models will be essential to discover and validate new treatment targets for these disorders
Moderate drinking? Alcohol consumption significantly decreases neurogenesis in the adult hippocampus
Different Periampullary Types and Subtypes Leading to Different Perioperative Outcomes of Pancreatoduodenectomy:Reality and Not a Myth; An International Multicenter Cohort Study
This international multicenter cohort study included 30 centers. Patients with duodenal adenocarcinoma (DAC), intestinal-type (AmpIT) and pancreatobiliary-type (AmpPB) ampullary adenocarcinoma, distal cholangiocarcinoma (dCCA), and pancreatic ductal adenocarcinoma (PDAC) were included. The primary outcome was 30-day or in-hospital mortality, and secondary outcomes were major morbidity (Clavien-Dindo 3b≥), clinically relevant post-operative pancreatic fistula (CR-POPF), and length of hospital stay (LOS). Results: Overall, 3622 patients were included in the study (370 DAC, 811 AmpIT, 895 AmpPB, 1083 dCCA, and 463 PDAC). Mortality rates were comparable between DAC, AmpIT, AmpPB, and dCCA (ranging from 3.7% to 5.9%), while lower for PDAC (1.5%, p = 0.013). Major morbidity rate was the lowest in PDAC (4.4%) and the highest for DAC (19.9%, p < 0.001). The highest rates of CR-POPF were observed in DAC (27.3%), AmpIT (25.5%), and dCCA (27.6%), which were significantly higher compared to AmpPB (18.5%, p = 0.001) and PDAC (8.3%, p < 0.001). The shortest LOS was found in PDAC (11 d vs. 14–15 d, p < 0.001). Discussion: In conclusion, this study shows significant variations in perioperative mortality, post-operative complications, and hospital stay among different periampullary cancers, and between the ampullary subtypes. Further research should assess the biological characteristics and tissue reactions associated with each type of periampullary cancer, including subtypes, in order to improve patient management and personalized treatment.</p
Southern Hemisphere humpback whales wintering off Central America: insights from water temperature into the longest mammalian migration
We report on a wintering area off the Pacific
coast of Central America for humpback whales
(Megaptera novaeangliae) migrating from feeding areas off Antarctica. We document seven individuals, including a mother/calf pair, that made this migration (approx. 8300 km), the longest movement undertaken by any mammal. Whales were observed as far north as 118N off Costa Rica, in an area also used by a boreal population during the opposite winter season, resulting in unique spatial
overlap between Northern and Southern Hemisphere populations. The occurrence of such a northerly wintering area is coincident with the development of an equatorial tongue of cold water in the eastern South Pacific, a pattern that is repeated in the eastern South Atlantic. A survey of location and water temperature at the wintering areas worldwide indicates that they are found in warm waters (21.1–28.38C), irrespective of latitude. We contend that while availability of suitable
reproductive habitat in the wintering areas is important at the fine scale, water temperature influences whale distribution at the basin scale. Calf development in warm water may lead to larger adult size and increased reproductive success, a strategy that supports the energy conservation hypothesis as a reason for migration
Sorção de fósforo em função do teor inicial e de sistemas de manejo de solos
A relação entre o P sorvido/P solução do solo pode ser influenciada pelo teor de P previamente sorvido e pelos sistemas de manejo. Este trabalho teve o objetivo de avaliar as modificações na capacidade de sorção máxima (Pmax) e na constante relacionada com a energia de ligação de P com os colóides (k) da isoterma de Langmuir, provocadas (a) pela inclusão do teor de P previamente sorvido (Ppre) e (b) por sistemas de manejo de solos. Coletaram-se, em maio de 1997, amostras de solo (Latossolo Vermelho distroférrico típico, Latossolo Vermelho distrófico típico e Argissolo Vermelho distrófico típico), em três camadas (0-2,5, 2,5-7,5 e 7,5-17,5 cm), de três experimentos instalados a partir de 1979, envolvendo os sistemas plantio direto e cultivo convencional com diferentes sucessões de cultura. O solo foi equilibrado com oito concentrações de P em solução de CaCl2 0,001 mol L-1. Após a agitação por 16 h, avaliou-se a concentração de P no sobrenadante. Os dados de P-sorvido e P-solução foram ajustados à equação de Langmuir, obtendo-se a Pmax e a k, considerando ou não o Ppre. A inclusão do Ppre no modelo de Langmuir aumenta, em média, 2,9 vezes o valor da k e não afeta a Pmax, no LVdf, e aumenta em todas as camadas, no LVd, e na camada superficial, no PVd. A Pmax é pouco influenciada pelos métodos de preparo do solo, sucessões de culturas e camadas amostradas