66 research outputs found
Interactions between energetic electrons and realistic whistler mode waves in the Jovian magnetosphere
The role of plasma waves in shaping the intense Jovian radiation belts is not well understood. In this study we use a realistic wave model based on an extensive survey from the Plasma Wave Investigation on the Galileo spacecraft to calculate the effect of pitch angle and energy diffusion on Jovian energetic electrons due to upper and lower band chorus. Two Earth-based models, the Full Diffusion Code and the Versatile Electron Radiation Belt code, are adapted to the case of the Jovian magnetosphere and used to resolve the interaction between chorus and electrons at L = 10. We also present a study of the sensitivity to the latitudinal wave coverage and initial electron distribution. Our analysis shows that the contribution to the electron dynamics from upper band chorus is almost negligible compared to that from lower band chorus. For 100 keV electrons, we observe that diffusion leads to redistribution of particles toward lower pitch angles with some particle loss, which could indicate that radial diffusion or interchange instabilities are important. For energies above >500 keV, an initial electron distribution based on observations is only weakly affected by chorus waves. Ideally, we would require the initial electron phase space density before transport takes place to assess the importance of wave acceleration, but this is not available. It is clear from this study that the shape of the electron phase space density and the latitudinal extent of the waves are important for both electron acceleration and loss
Adaptação ao cultivo e valorização de Lavandula luisieri
Foram estudadas diversas populações de Lavandula luisieri (Rozeira) Rivas-Martínez
endémicas da Península Ibérica (Beira Interior, Castilla-la-Mancha e Andaluzia; acessos
de Casal da Fraga, Mata, Penamacor e Vila Velha de Ródão – Portugal; Toledo e
Sevilha – Espanha), comparando as populações relativamente ao óleo essencial
(quantitativamente e qualitativamente), assim como, a sua actividade insecticida sobre
pragas fitófagas (Spodoptera littoralis, Mysus persicae e Leptinotarsa decemlineata).
Em função dos seus componentes escolheram-se as duas populações mais interessantes
em termos da sua actividade biológica (Penamacor e Toledo) e instalaram-se dois
campos produtivos em Castelo Branco e Saragoça, por forma a inferir sobre a influência
do local de produção na qualidade do material vegetal obtido. Será fornecida
informação técnica sobre a instalação destes campos
Nanotechnology-Based Targeted Drug Delivery: An Emerging Tool to Overcome Tuberculosis
The appearance and rapid spread of drug resistant strains of tuberculosis (TB), one of the deadliest infectious diseases, pose a serious threat to public health and increase the need for shorter, less toxic, and more effective therapies. Developing new drugs is difficult and often associated with side effects, so nanotechnology has emerged as a tool to improve current treatments and to rescue drugs having elevated toxicity or poor solubility. Due to their size and surface chemistry, antimicrobial-loaded nanocarriers are avidly taken up by macrophages, the main cells hostingMycobacterium tuberculosis. Macrophages are continuously recruited to infected areas, they can transport drugs with them, making passive targeting a good strategy for TB treatment. Active targeting (decorating surface of nanocarriers with ligands specific to receptors displayed by macrophages) further increases local drug concentration, and thus treatment efficacy. Although in in vivo studies, nanocarriers are often administered intravenously in order to avoid inaccurate dosage in animals, translation to humans requires more convenient routes like pulmonary or oral administration. This report highlights the importance and progress of pulmonary administration, passive and active targeting strategies toward bacteria reservoirs to overcome the challenges in TB treatment
Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer.
To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L 1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4 C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature
Asistencia pediátrica dental: ¿cumplen las familias?
Antecedentes: la pediatría preventiva ha demostrado ser uno de los pilares imprescindibles para mantener el nivel de bienestar en la infancia. No obstante, aún encontramos ciertos campos que no parecen estar lo suficientemente
evaluados, como por ejemplo, el estado dental de los pacientes pediátricos. La primera visita al dentista, un hecho fundamental para controlar el correcto crecimiento y estado del aparato estomatológico, no suele estar reglada por los pediatras, quedando en muchas ocasiones a la voluntad de los padres la edad a la cual llevan a sus hijos al dentista. Este pequeño estudio deviene novedoso puesto que no existen muchas publicaciones que indaguen en los factores sociales que llevan a un paciente pediátrico a acudir por primera vez al dentista. Objetivos: estudiamos una muestra de pacientes en edad pediátrica de nuestro medio y pretendemos averiguar si un factor social, como el número de hijos que tiene una familia, puede influir en el hecho de acudir por primera vez al especialista estomatológico.
Material y método: se recogen datos de todos los pacientes pediátricos de edades comprendidas entre los 1 y los 12 años que acuden a la Clínica Dental Pérez Colomina entre los años 2016 y 2017. Dicha clínica, en funcionamiento desde hace 25 años en el núcleo urbano de la ciudad de Zaragoza, se puede considerar como un centro que cuenta con una muestra representativa de la atención pediátrica puesto que en ella se atienden a niños procedentes tanto del sistema público de atención bucodental infantil y juvenil (PABIJ), como de mutualistas de la administración pública, así como de otras compañías concertadas y privadas. En la encuesta se recogen entre otros datos, la edad a la que el paciente pediátrico acude por primera vez al dentista, así como el número de hermanos que presenta.
Resultados: del total de hijos únicos, a los cuatro años un 28,55% de los hijos ha acudido al dentista, mientras que un 80,48% ya ha acudido al menos una vez a la edad de seis años. Del total de hijos con hermanos, a los cuatro años un 42,5% de los hijos ha ido al dentista, al tiempo que un 89,89% ya ha acudido a la consulta dental al menos una vez a la edad de seis años. Conclusiones: llama la atención que los pacientes pediátricos con hermanos son llevados a la consulta dental antes que los hijos únicos, hecho que puede ser motivado porque al tratar de atender las necesidades odontológicas de un hijo, se aprovecha para controlar al resto de los niños que componen la familia. Deberían realizarse más investigaciones al respecto que ayuden a fomentar el control estomatológico tanto por parte de los pediatras como de los padres.
Background: Preventive pediatrics has proven to be one of the essential pillars to maintain the level of well-being in childhood. However, we still find certain fields that do not seem to be sufficiently evaluated, such as the dental status of pediatric patients. The first visit to the dentist, a fundamental fact to control the proper growth and state of the stomatological apparatus, is not usually regulated by the pediatricians, leaving many times at the will of the parents the age at which they take their children to the dentist. This small study becomes novel since there are not many publications that investigate the social factors that lead a pediatric patient to visit the dentist for the first time. Objectives: We studied a sample of pediatric patients in our environment and we intend to find out if a social factor, such as the number of children a family has, may influence the fact of going to the stomatologic specialist for the first time. Material and method: data are collected from all pediatric patients between the ages of 1 and 12 who attend the Pérez Colomina Dental Clinic between 2016 and 2017. This clinic has been in operation for 25 years in the urban area of the city of Zaragoza, can be considered as a center that has a representative sample of pediatric care since it caters to children from both the public system of oral care for children and youth (PABIJ), as well as mutualists of the public administration and other companies concerted and private. The survey includes, among other data, the age at which the pediatric patient comes to the dentist for the first time, as well as the number of siblings he presents.
Results: Of the total of only children, at four years, 28.55% of the children went to the dentist, while 80.48% had attended at least once at the age of six. Of the total of children with siblings, at four years 42.5% of the children went to the dentist, while 89.89% had already gone to the dental office at least once at the age of six. Conclusions: It is striking that pediatric patients with siblings are taken to the dental office before the only children, a fact that may be motivated because when trying to attend to the dental needs of a child, it is used to control the rest of the infants that make up the family. More research should be done in this regard to help promote stomatological control by both pediatricians and parents
Bridging the gap between stellar-mass black holes and ultraluminous X-ray sources
The X-ray spectral and timing properties of ultraluminous X-ray sources
(ULXs) have many similarities with the very high state of stellar-mass black
holes (power-law dominated, at accretion rates greater than the Eddington
rate). On the other hand, their cool disk components, large characteristic
inner-disk radii and low characteristic timescales have been interpreted as
evidence of black hole masses ~ 1000 Msun (intermediate-mass black holes). Here
we re-examine the physical interpretation of the cool disk model, in the
context of accretion states of stellar-mass black holes. In particular, XTE
J1550-564 can be considered the missing link between ULXs and stellar-mass
black holes, because it exhibits a high-accretion-rate, low-disk-temperature
state (ultraluminous branch). On the ultraluminous branch, the accretion rate
is positively correlated with the disk truncation radius and the bolometric
disk luminosity, while it is anti-correlated with the peak temperature and the
frequency of quasi-periodic-oscillations. Two prototypical ULXs (NGC1313 X-1
and X-2) also seem to move along that branch. We use a phenomenological model
to show how the different range of spectral and timing parameters found in the
two classes of accreting black holes depends on both their masses and accretion
rates. We suggest that ULXs are consistent with black hole masses ~ 50-100
Msun, moderately inefficiently accreting at ~20 times Eddington.Comment: 11 pages, accepted for publication in Astrophysics and Space Science.
Based on work presented at the Fifth Stromlo Symposium, Australian National
University, Dec 200
Prevention of diet-induced obesity by apple polyphenols in Wistar rats through regulation of adipocyte gene expression and DNA methylation patterns
This study was conducted to determine the mechanisms implicated in the beneficial effects of apple polyphenols (APs) against diet-induced obesity in Wistar rats, described in a previous study from our group. Supplementation of high-fat sucrose diet with AP prevented adiposity increase by inhibition of adipocyte hypertrophy. Rats supplemented with AP exhibited improved glucose tolerance while adipocytes isolated from these rats showed an enhanced lipolytic response to isoproterenol. AP intake led to reduced Lep, Plin, and sterol regulatory element binding transcription factor 1 (Srebf1) mRNA levels and increased aquaporin 7 (Aqp7), adipocyte enhancer binding protein 1 (Aebp1), and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (Ppargc1a) mRNA levels in epididymal adipocytes. In addition, we found different methylation patterns of Aqp7, Lep, Ppargc1a, and Srebf1 promoters in adipocytes from apple-supplemented rats compared to high-fat sucrose fed rats. The administration of AP protects against body weight gain and fat deposition and improves glucose tolerance in rats. We propose that AP exerts the antiobesity effects through the regulation of genes involved in adipogenesis, lipolysis, and fatty acid oxidation, in a process that could be mediated in part by epigenetic mechanisms
Optimization of a Solid-Phase Microextraction method for the Gas Chromatography–Mass Spectrometry analysis of blackberry (Rubus ulmifolius Schott) fruit volatiles
Geographic population structure analysis of worldwide human populations infers their biogeographical origins
The search for a method that utilizes biological information to predict humans’ place of origin has occupied scientists for millennia. Over the past four decades, scientists have employed genetic data in an effort to achieve this goal but with limited success. While biogeographical algorithms using next-generation sequencing data have achieved an accuracy of 700 km in Europe, they were inaccurate elsewhere. Here we describe the Geographic Population Structure (GPS) algorithm and demonstrate its accuracy with three data sets using 40,000–130,000 SNPs. GPS placed 83% of worldwide individuals in their country of origin. Applied to over 200 Sardinians villagers, GPS placed a quarter of them in their villages and most of the rest within 50 km of their villages. GPS’s accuracy and power to infer the biogeography of worldwide individuals down to their country or, in some cases, village, of origin, underscores the promise of admixture-based methods for biogeography and has ramifications for genetic ancestry testing
- …