537 research outputs found
Dust Transport in Protostellar Disks Through Turbulence and Settling
We apply ionization balance and MHD calculations to investigate whether
magnetic activity moderated by recombination on dust can account for the mass
accretion rates and the mid-infrared spectra and variability of protostellar
disks. The MHD calculations use the stratified shearing-box approach and
include grain settling and the feedback from the changing dust abundance on the
resistivity of the gas. The two-decade spread in accretion rates among T Tauri
stars is too large to result solely from variety in the grain size and stellar
X-ray luminosity, but can be produced by varying these together with the disk
magnetic flux. The diversity in the silicate bands can come from the coupling
of grain settling to the distribution of the magneto-rotational turbulence,
through three effects: (1) Recombination on grains yields a magnetically
inactive dead zone extending above two scale heights, while turbulence in the
magnetically active disk atmosphere overshoots the dead zone boundary by only
about one scale height. (2) Grains deep in the dead zone oscillate vertically
in waves driven by the turbulent layer above, but on average settle at the
laminar rates, so the interior of the dead zone is a particle sink and the disk
atmosphere becomes dust-depleted. (3) With sufficient depletion, the dead zone
is thinner and mixing dredges grains off the midplane. The MHD results also
show that the magnetic activity intermittently lifts clouds of dust into the
atmosphere. The photosphere height changes by up to one-third over a few
orbits, while the extinction along lines of sight grazing the disk surface
varies by factors of two over times down to 0.1 orbit. We suggest that the
changing shadows cast by the dust clouds on the outer disk are a cause of the
daily to monthly mid-infrared variability in some young stars. (Abridged.)Comment: ApJ in pres
Role of taxanes in advanced prostate cancer
[Abstract] Advanced prostate cancer is an androgen-dependent disease for which the initial treatment is an androgen deprivation maneuver. However, some primary resistances to hormonal treatment occur with increasing incidence throughout the evolution of the disease. The taxanes, docetaxel and cabazitaxel, exert their action at multiple levels at the tumor cell: besides inhibiting the mitosis and inducing the cell death, they induce the nuclear accumulation of FOXO1, a potent nuclear factor that acts against the activation of androgen receptor inhibiting the transcription of AR-V7 variant associated with the development of resistances to abiraterone and enzalutamide. Docetaxel, as first-line therapy, and cabazitaxel, as second-line therapy, have demonstrated to increase the survival in castration-resistant prostate cancer. The results from last studies either on high-risk localized disease or on androgen-sensitive tumors demonstrate the increasing role of taxanes at earlier states of prostate cancer
A new rebbachisaurid sauropod from the Aptian–Albian, Lower Cretaceous Rayoso Formation, Neuquén, Argentina
Rebbachisaurids are a group of basal diplodocimorph sauropods that diversified in Gondwana at the end of the Early
Cretaceous and the beginning of the Late Cretaceous. It is a group of great palaeobiogeographical interest, for it clearly
illustrates various processes of dispersal throughout Gondwana and to Laurasia prior to the breakup of Africa and South
America. However, the relationships within the group are still under discussion owing to the scarcity of cranial material
that would help clarify them. In the present paper we describe the new rebbachisaurid Lavocatisaurus agrioensis gen. et
sp. nov. from the Aptian–Albian (Lower Cretaceous) of Neuquén (Argentina). Remains have been recovered belonging
to an adult specimen (holotype) and two immature specimens (paratypes). Taken together, almost all the bones of the
taxon are represented, including most of the cranium. Lavocatisaurus agrioensis gen. et sp. nov. is the first rebbachisaurid
from Argentina with an almost complete cranium, making it possible to recognize differences with respect to
other rebbachisaurids, such as the highly derived Nigersaurus. Among its most notable characters are the presences of
a large preantorbital fenestra and maxillary teeth that are significantly larger than those of the dentary. Our phylogenetic
study places Lavocatisaurus amongst basal rebbachisaurids, as the sister lineage to Khebbashia (the clade formed by
Limaysaurinae + Rebbachisaurinae). This position, which is somewhat more derived than that previously suggested
for Comahuesaurus and Zapalasaurus (the Argentinean rebbachisaurids closest in geographical and geological terms),
reaffirms the presence of different basal rebbachisaurid lineages in the Early Cretaceous of Patagonia
Design of a Soil Cutting Resistance Sensor for Application in Site-Specific Tillage
One objective of precision agriculture is to provide accurate information about soil and crop properties to optimize the management of agricultural inputs to meet site-specific needs. This paper describes the development of a sensor equipped with RTK-GPS technology that continuously and efficiently measures soil cutting resistance at various depths while traversing the field. Laboratory and preliminary field tests verified the accuracy of this prototype soil strength sensor. The data obtained using a hand-operated soil cone penetrometer was used to evaluate this field soil compaction depth profile sensor. To date, this sensor has only been tested in one field under one gravimetric water content condition. This field test revealed that the relationships between the soil strength profile sensor (SSPS) cutting force and soil cone index values are assumed to be quadratic for the various depths considered: 0–10, 10–20 and 20–30 cm (r2 = 0.58, 0.45 and 0.54, respectively). Soil resistance contour maps illustrated its practical value. The developed sensor provides accurate, timely and affordable information on soil properties to optimize resources and improve agricultural economyMinistry of Science and Innovation RTA2006-00058-C03-0
411 LONGITUDINAL CHANGES IN THE SPATIAL DISTRIBUTION OF CARTILAGE MR T2 IN A SUBSET OF PATIENTS FROM THE OSTEOARTHRITIS INITIATIVE
Ghrelin neutralization during fasting-refeeding cycle impairs the recuperation of body weight and alters hepatic energy metabolism
Ghrelin, a hormone whose levels increase during food deprivation, plays a pivotal role in the regulation of food intake, energy metabolism and storage, as well as in insulin sensitivity. Here, we investigated the effects of acyl-ghrelin neutralization with the acyl-ghrelin-binding compound NOX-B11(2) during the fasting-refeeding cycle. Our data demonstrate that ghrelin neutralization with NOX-B11(2) impairs recuperation of lost body weight after food deprivation. Analysis of enzymes involved in glucose and lipid metabolism in liver of fed, fasted and refed rats revealed that neutralization of acyl-ghrelin resulted in minor decreases in the enzymes of glycolytic and lipogenic pathways during fasting. However, during refeeding these enzymes as well as glycogen levels recovered more slowly when acyl-ghrelin was blocked. The high levels of ghrelin in response to food deprivation may contribute to an adequate decrease in hepatic glycolytic and lipogenic enzymes and aid in the recovery of body weight and energetic reserves once food becomes available after the fasting period
Results of D-IMPACT
Summary Aims:  Diagnosis IMprovement in PrimAry Care Trial (D-IMPACT) was a prospective, multicentre epidemiological study in three European countries to identify the optimal subset of simple tests applied in primary care to diagnose benign prostatic hyperplasia (BPH) in men who spontaneously present with lower urinary tract symptoms (LUTS). Methods:  Consecutive male patients aged ≥ 50 years who spontaneously attended their regular general practitioner (GP) office with LUTS were eligible for inclusion if they had not previously undergone BPH diagnostic tests or received treatment for BPH. Patients were assessed on three occasions, twice by their regular GP (visits 1 and 2) and once by a urologist (visit 3). The diagnostic accuracy of each variable was determined using the urologists' final BPH diagnosis (at visit 3) as gold-standard. Independent variables analysed were as follows: age; BPH diagnosis performed by GP in visit 1 (yes/no); probability of BPH diagnosis assessed by GP in visit 1; urinalysis (normal/abnormal); prostate-specific antigen (PSA); International Prostate Symptom Score (IPSS); diagnosis of BPH performed by GP in visit 2 (yes/no); and probability of BPH diagnosis assessed by GP in visit 2. Statistically significant variables (p 1.5 ng/ml and prostate volume ≥ 30 cm3). Among the independent variables analysed, only age, IPSS and PSA showed a statistically significant relationship with BPH diagnosis. In a logistic regression model including age, IPSS, PSA and probability of BPH (based on physical examination and symptoms), positive predictive value (PPV) was 77.1%. Exclusion of BPH probability resulted in a PPV of 75.7%. Conclusions:  A diagnostic algorithm including only objective variables (age, IPSS and PSA), easily implemented in any GP office, allows GPs to accurately diagnose BPH in approximately three-quarters of patients spontaneously reporting LUTS
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