297 research outputs found
Unexpected Occurrence of Mesospheric Frontal Gravity Wave Events Over the South Pole (90 degrees S)
Since 2010, Utah State University has operated an infrared Advanced Mesospheric Temperature Mapper at the Amundsen–Scott South Pole station to investigate the upper atmosphere dynamics and temperature deep within the vortex. A surprising number of “frontal” gravity wave events (86) were recorded in the mesospheric OH(3,1) band intensity and rotational temperature images (typical altitude of ~87 km) during four austral winters (2012–2015). These events are gravity waves (GWs) characterized by a sharp leading wave front followed by a quasi-monochromatic wave train that grows with time. A particular subset of frontal gravity wave events has been identified in the past (Dewan & Picard, 1998) as “bores.” These are usually associated with wave ducting within stable mesospheric inversion layers, which allow them to propagate over very large distances. They have been observed on numerous occasions from low-latitude and midlatitude sites, but to date, very few have been reported at high latitudes. This study provides new analyses of the characteristics of frontal events at high latitudes and shows that most of them are likely ducted. The occurrence of these frontal GW events over this isolated region strongly supports the existence of horizontally extensive mesospheric thermal inversion layers over Antarctica, leading to regions of enhanced stability necessary for GW trapping and ducting
Agronomic Potential and Nutritive Value of Promising \u3ci\u3eLeucaena\u3c/i\u3e Species in the Yucatan Peninsula
Two experiments were carried out in order to evaluate the agronomic potential, the nutritive value and the tolerance to psyllid (Heteropsilla cubana) of nine Leucaena species. A randomized block design with four repetitions was used. There were significant (P\u3c 0.01) differences on dry matter production (i.e. leaf and twigs yield ). L. collinsii showed the most promising result, which could be related to its high psyllid tolerance. In a second experiment, the preference indices of Leucaena species was assessed with sixteen male pelibuey sheep in a cafeteria trial. There were significant (P\u3c 0.0001) differences among Leucaena species. L. esculenta paniculata was the species most preferred . There was no relationship between chemical composition (i.e. ADF, NDF, and polyphenols) and preference and psyllid tolerance
Reestructura de los espacios de talleres holísticos en el albergue CN A.C.
El contenido de este documento incluye el trabajo elaborado durante el semestre de otoño 2018, en el cual desde la perspectiva arquitectónica y psicológica se hizo el análisis de los talleres del departamento de C.R.E. donde a partir de la reubicación de los salones para los talleres, el objetivo principal era crear un espacio que permitiera el desarrollo integral de los residentes del albergue la Ciudad de los Niños. Esto aunado a la implementación de los nuevos talleres holísticos, donde ahora con esta modalidad busca que cada sesión sea planeada por los psicólogos desde una perspectiva en la que se trabajen las emociones por medio de un enfoque de Arteterapia, además de esto la intervención en los salones de talleres desde la
visión arquitectónica, para propiciar un mejor espacio donde se puedan desarrollar este tipo de actividades, en espacios apropiados, dignos y motivadores de la actividad de residentes y formadores- talleristas.ITESO, A.C.ITESO- ALBERGUE CIUDAD DE LOS NIÑO
Electronic States in Diffused Quantum Wells
In the present study we calculate the energy values and the spatial
distributions of the bound electronic states in some diffused quantum wells.
The calculations are performed within the virtual crystal approximation, spin dependent empirical tight-binding model and the surface Green
function matching method. A good agreement is found between our results and
experimental data obtained for AlGaAs/GaAs quantum wells with thermally induced
changes in the profile at the interfaces. Our calculations show that for
diffusion lengths {\AA} the transition (C3-HH3) is not
sensitive to the diffusion length, but the transitions (C1-HH1), (C1-LH1),
(C2-HH2) and (C2-LH2) display large "blue shifts" as L_{D} increases. For
diffusion lengths {\AA} the transitions (C1-HH1) and (C1-LH1)
are less sensitive to the L_{D} changes than the (C3-HH3) transition. The
observed dependence is explained in terms of the bound states spatial
distributions.Comment: ReVTeX file, 7pp., no macros, 4 figures available on the reques
An Army of Me: Sockpuppets in Online Discussion Communities
In online discussion communities, users can interact and share information
and opinions on a wide variety of topics. However, some users may create
multiple identities, or sockpuppets, and engage in undesired behavior by
deceiving others or manipulating discussions. In this work, we study
sockpuppetry across nine discussion communities, and show that sockpuppets
differ from ordinary users in terms of their posting behavior, linguistic
traits, as well as social network structure. Sockpuppets tend to start fewer
discussions, write shorter posts, use more personal pronouns such as "I", and
have more clustered ego-networks. Further, pairs of sockpuppets controlled by
the same individual are more likely to interact on the same discussion at the
same time than pairs of ordinary users. Our analysis suggests a taxonomy of
deceptive behavior in discussion communities. Pairs of sockpuppets can vary in
their deceptiveness, i.e., whether they pretend to be different users, or their
supportiveness, i.e., if they support arguments of other sockpuppets controlled
by the same user. We apply these findings to a series of prediction tasks,
notably, to identify whether a pair of accounts belongs to the same underlying
user or not. Altogether, this work presents a data-driven view of deception in
online discussion communities and paves the way towards the automatic detection
of sockpuppets.Comment: 26th International World Wide Web conference 2017 (WWW 2017
Stable Thermally-Modulated Nanodroplet Ultrasound Contrast Agents
Liquid perfluorocarbon-based nanodroplets are stable enough to be used in extravascular imaging, but provide limited contrast enhancement due to their small size, incompressible core, and small acoustic impedance mismatch with biological fluids. Here we show a novel approach to overcoming this limitation by using a heating–cooling cycle, which we will refer to as thermal modulation (TM), to induce echogenicity of otherwise stable but poorly echogenic nanodroplets without triggering a transient phase shift. We apply thermal modulation to high-boiling point tetradecafluorohexane (TDFH) nanodroplets stabilized with a bovine serum albumin (BSA) shell. BSA-TDFH nanodroplets with an average diameter under 300 nanometers showed an 11.9 ± 5.4 mean fold increase in echogenicity on the B-mode and a 13.9 ± 6.9 increase on the nonlinear contrast (NLC) mode after thermal modulation. Once activated, the particles maintained their enhanced echogenicity (p \u3c 0.001) for at least 13 h while retaining their nanoscale size. Our data indicate that thermally modulated nanodroplets can potentially serve as theranostic agents or sensors for various applications of contrast-enhanced ultrasound
Long-term efficacy and safety results of taliglucerase alfa through 5years in adult treatment-naïve patients with Gaucher disease
Taliglucerase alfa, the first available plant cell-expressed recombinant therapeutic protein, is an enzyme replacement therapy approved for Gaucher disease (GD). PB-06-001, a pivotal phase 3, multicenter, randomized, double-blind, parallel-dose study investigated taliglucerase alfa 30 or 60U/kg every other week through 9months in treatment-naïve adults with GD; 30-month extension study PB-06-003 followed. Patients completing PB-06-001 and PB-06-003 could continue treatment in PB-06-007. Nineteen patients enrolled in PB-06-007 (30U/kg, n=8; 60U/kg, n=9; dose adjusted, n=2); 17 completed 5 total years of treatment. In these 3 groups, respectively, taliglucerase alfa resulted in mean decreases in spleen volume (-8.7, -6.9, -12.4 multiples of normal), liver volume (-0.6, -0.4, -0.5 multiples of normal), chitotriosidase activity (-83.1%, -93.4%, -87.9%), and chemokine (CC motif) ligand 18 concentration (-66.7%, -83.3%, -78.9%), as well as mean increases in hemoglobin concentration (+2.1, +2.1, +1.8mg/dL) and platelet count (+31,871, +106,800, +34,000/mm3). The most common adverse events were nasopharyngitis and arthralgia. Most adverse events were mild/moderate; no serious adverse events were considered treatment-related. These results demonstrate continued improvement of disease parameters during 5years of taliglucerase alfa therapy in 17 treatment-naive patients with no new safety concerns, extending the taliglucerase alfa clinical efficacy and safety dataset. This study was registered at www.clinicaltrials.gov as NCT01422187
Magnetooptical effects in quantum wells irradiated with light pulses
The method of detection and investigation of the magnetopolaron effect in the
semiconductor quantum wells (QW) in a strong magnetic field, based on pulse
light irradiation and measuring the reflected and transmitted pulses, has been
proposed. It has been shown that a beating amplitude on the frequencies,
corresponding to the magnetopolaron energy level splitting, depends strongly
from the exciting pulse width. The existence of the time points of the total
reflection and total transparency has been predicted. The high orders of the
perturbation theory on electron-electromagnetic field interaction have been
taken into account.Comment: 5 pages, 5 figures with captions, corrected typos, figures are
reedeted to improve their quality in accordance with the Referee requirement;
Phys. Rev. B, Brief Reports, submitted for publicatio
Computer science approach to the stellar fabric of violent starforming regions in AGN
In order to analyse the large numbers of Seyfert galaxy spectra available at
present, we are testing new techniques to derive their physical parameters
fastly and accurately.
We present an experiment on such a new technique to segregate old and young
stellar populations in galactic spectra using machine learning methods. We used
an ensemble of classifiers, each classifier in the ensemble specializes in
young or old populations and was trained with locally weighted regression and
tested using ten-fold cross-validation. Since the relevant information
concentrates in certain regions of the spectra we used the method of sequential
floating backward selection offline for feature selection.
Very interestingly, the application to Seyfert galaxies proved that this
technique is very insensitive to the dilution by the Active Galactic Nucleus
(AGN) continuum. Comparing with exhaustive search we concluded that both
methods are similar in terms of accuracy but the machine learning method is
faster by about two orders of magnitude.Comment: 4 pages, 1 figure, Contribution to IAU Symp. 222, The interplay among
Black Holes, Stars and ISM in Galactic Nuclei, Gramado, Brazil, 200
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