3,635 research outputs found
Effect of long-range Coulomb interaction on shot-noise suppression in ballistic transport
We present a microscopic analysis of shot-noise suppression due to long-range
Coulomb interaction in semiconductor devices under ballistic transport
conditions. An ensemble Monte Carlo simulator self-consistently coupled with a
Poisson solver is used for the calculations. A wide range of injection-rate
densities leading to different degrees of suppression is investigated. A sharp
tendency of noise suppression at increasing injection densities is found to
scale with a dimensionless Debye length related to the importance of
space-charge effects in the structure.Comment: RevTex, 4 pages, 4 figures, minor correction
Physicochemical and Sensory Evaluation Data to Drive the Development of a Green Chili Pepper Hot Sauce from Unexploited Raw Materials
The present study shows the set of analyses conducted during the development of a hot chili pepper sauce to valorize green peppers usually discarded in the Espelette region (France). A traditional production process was used as the inspiration for product development, and two different fermentation processes were assessed and characterized by measuring pH, sugar content, instrumental color, volatile composition, and conducting sensory (discriminant test) and microbiological analyses (total plate count). Significant differences were observed among pepper mash samples with respect to their physicochemical characteristics, but the products were considered similar from a sensory standpoint. Both sensory and physicochemical tests suggested that the ingredients added to make the sauces were determinant and had a higher impact on the organoleptic profile of the final product than the fermentation process. Finally, a Napping® test was conducted to determine the attributes that could differentiate the product from the hot sauces found in the current market. The results of the present research allowed the optimization of the elaboration process of the new product, saving time and ingredient costs. The procedures shown in the study could be used as an example of a new product development process in which physicochemical and sensory data are collected and used for decision making.The present study shows the set of analyses conducted during the development of a hot chili pepper sauce to valorize green peppers usually discarded in the Espelette region (France). A traditional production process was used as the inspiration for product development, and two different fermentation processes were assessed and characterized by measuring pH, sugar content, instrumental color, volatile composition, and conducting sensory (discriminant test) and microbiological analyses (total plate count). Significant differences were observed among pepper mash samples with respect to their physicochemical characteristics, but the products were considered similar from a sensory standpoint. Both sensory and physicochemical tests suggested that the ingredients added to make the sauces were determinant and had a higher impact on the organoleptic profile of the final product than the fermentation process. Finally, a Napping® test was conducted to determine the attributes that could differentiate the product from the hot sauces found in the current market. The results of the present research allowed the optimization of the elaboration process of the new product, saving time and ingredient costs. The procedures shown in the study could be used as an example of a new product development process in which physicochemical and sensory data are collected and used for decision making
Rasgos de personalidad y burnout en médicos de familia
ObjetivoInvestigar los rasgos de personalidad que podrĂan asociarse con puntuaciones altas en las escalas de burnout (Maslach Burnout Inventory) en mĂ©dicos de atenciĂłn primaria.DiseñoEstudio observacional, descriptivo, transversal.EmplazamientoNoventa y tres centros de atenciĂłn primaria de la ciudad de Barcelona y las comarcas del norte de la provincia: Vallès Oriental, Vallès Occidental, Maresme, Osona, Bages y BerguedĂ (regiĂłn sanitaria centro).MĂ©todoEncuesta directa por entrevista personal o grupal a 528 mĂ©dicos de atenciĂłn primaria. Se administraron 3 cuestionarios: uno de datos sociodemográficos generales, el Maslasch Burnout Inventory (MBI) y el test de personalidad de Cattell 16 PF-5.ResultadosUn 40% de los encuestados presentaba algĂşn sĂntoma de burnout sin diferencia entre sexos. De Ă©stos, un 12,4% manifestaba niveles muy altos de «quemazĂłn» profesional. Los sujetos con criterios de burnout obtuvieron puntuaciones significativamente diferentes en los rasgos de estabilidad, tensiĂłn y vigilancia y en la dimensiĂłn ansiedad.ConclusionesAlgunos rasgos de personalidad, como la baja estabilidad emocional, la tensiĂłn y la ansiedad, se asocian de manera significativa a puntuaciones altas de burnoutExisten algunas diferencias entre estos factores internos por sexo.ObjectiveWith this research we try to study personality traits that could be associated with high punctuation at burnout scales (Maslach Burnout Inventory) in primary care physicians.DesignObservational descriptive transversal studySetting93 primary care centres in Barcelona-city and the northern province's region: Vallès Oriental, Vallès Occidental, Maresme, Osona, Bages and BerguedĂ (centre sanitary region).MethodIndividual or collective direct interview to 528 primary care physicians. Three questioners were administrated: a sociodemographyc items one, the Maslach Burnout Inventory (MBI) and the Cattell personality test 16-PF.ResultsThe 40% of the interviewed physicians had some burnout symptom without any difference between sexes. The 12.4% of these ones showed very high burnout levels. Those subjects with burnout criteria punctuated different at stability, tension and vigilance traits and anxiety dimension.ConclusionSome personality traits like low stability, the tension and the anxiety are associated with high punctuation of burnout
A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite I. The observational data
Spectral line surveys are useful since they allow identification of new
molecules and new lines in uniformly calibrated data sets. Nonetheless, large
portions of the sub-millimetre spectral regime remain unexplored due to severe
absorptions by H2O and O2 in the terrestrial atmosphere. The purpose of the
measurements presented here is to cover wavelength regions at and around 0.55
mm -- regions largely unobservable from the ground. Using the Odin
astronomy/aeronomy satellite, we performed the first spectral survey of the
Orion KL molecular cloud core in the bands 486--492 and 541--576 GHz with
rather uniform sensitivity (22--25 mK baseline noise). Odin's 1.1 m size
telescope, equipped with four cryo-cooled tuneable mixers connected to broad
band spectrometers, was used in a satellite position-switching mode. Two mixers
simultaneously observed different 1.1 GHz bands using frequency steps of 0.5
GHz (25 hours each). An on-source integration time of 20 hours was achieved for
most bands. The entire campaign consumed ~1100 orbits, each containing one hour
of serviceable astro-observation. We identified 280 spectral lines from 38
known interstellar molecules (including isotopologues) having intensities in
the range 80 to 0.05 K. An additional 64 weak lines remain unidentified. Apart
from the ground state rotational 1(1,0)--1(0,1) transitions of ortho-H2O, H218O
and H217O, the high energy 6(2,4)--7(1,7) line of para-H2O and the
HDO(2,0,2--1,1,1) line have been observed, as well as the 1,0--0,1 lines from
NH3 and its rare isotopologue 15NH3. We suggest assignments for some
unidentified features, notably the new interstellar molecules ND and SH-.
Severe blends have been detected in the line wings of the H218O, H217O and 13CO
lines changing the true linewidths of the outflow emission.Comment: 21 pages, 10 figures, 7 tables, accepeted for publication in
Astronomy and Astrophysics 30 August 200
The magnesium paradigm in IRC+10216: Discovery of MgCH, MgCN, MgCH, and MgCN
We found four series of harmonically related lines in IRC\,+10216 with the
Yebes\,40m and IRAM\,30m telescopes. The first series corresponds to a molecule
with a rotational constant, , of 1448.59940.0013 MHz and a distortion
constant, , of 63.451.15 Hz and covers upper quantum numbers from
=11 up to 33 (B1449). The second series is fitted with
=1446.93800.0098 MHz and =9123 Hz and covers upper quantum
numbers from =11 up to 17 (B1447). The third series is fitted with
=598.74950.0011 MHz and D=6.130.43 Hz and covers quantum numbers
from =26 up to 41 (B599). Finally, the frequencies of the last series of
lines can be reproduced with =594.31760.0026 MHz and =4.921.16
Hz (B594). The large values of point toward four metal-bearing carriers.
After exploring all plausible candidates containing Na, Al, Mg, and other
metals, our ab initio calculations indicate that the cations MgCH,
MgCN, MgCH, and MgCN must be the carriers of B1449,
B1447, B599, and B594, respectively. These cations could be formed by the
radiative association of Mg with CH, CN, CH, and CN,
respectively. We calculated the radiative association rate coefficient of
Mg with CH, CN, CH, and CN and incorporated them in our
chemical model. The results confirm that the Mg-bearing cations can be formed
through these radiative association reactions in the outer layers of
IRC\,+10216. This is the first time that cationic metal-bearing species have
been found in space. These results provide a new paradigm on the reactivity of
ionized metals with abundant radicals and open the door for further
characterization of similar species in metal-rich astrophysical environments
Influence of nuclear structure on sub-barrier hindrance in Ni+Ni fusion
Fusion-evaporation cross sections for Ni+Ni have been measured
down to the 10 nb level. For fusion between two open-shell nuclei, this is the
first observation of a maximum in the -factor, which signals a strong
sub-barrier hindrance. A comparison with the Ni+Ni,
Ni+Ni, and Ni+Ni systems indicates a strong
dependence of the energy where the hindrance occurs on the stiffness of the
interacting nuclei.Comment: Submitted to Phys. Rev. Lett. 4 pages, 3 figure
Viscoelastic Depinning of Driven Systems: Mean-Field Plastic Scallops
We have investigated the mean field dynamics of an overdamped viscoelastic
medium driven through quenched disorder. The model introduced incorporates
coexistence of pinned and sliding degrees of freedom and can exhibit continuous
elastic depinning or first order hysteretic depinning. Numerical simulations
indicate mean field instabilities that correspond to macroscopic stick-slip
events and lead to premature switching. The model is relevant for the dynamics
of driven vortex arrays in superconductors and other extended disordered
systems.Comment: 4 pages, 2 figure
Equilibration and Dynamic Phase Transitions of a Driven Vortex Lattice
We report on the observation of two types of current driven transitions in
metastable vortex lattices. The metastable states, which are missed in usual
slow transport measurements, are detected with a fast transport technique in
the vortex lattice of undoped
2H-NbSe. The transitions are seen by following the evolution of these
states when driven by a current. At low currents we observe an equilibration
transition from a metastable to a stable state, followed by a dynamic
crystallization transition at high currents.Comment: 5 pages, 4 figure
A Novel Requirement for Janus Kinases as Mediators of Drug Resistance Induced by Fibroblast Growth Factor-2 in Human Cancer Cells
The development of resistance to chemotherapy is a major cause of cancer-related death. Elucidating the mechanisms of drug resistance should thus lead to novel therapeutic strategies. Fibroblast growth factor (FGF)-2 signaling induces the assembly of a multi-protein complex that provides tumor cells with the molecular machinery necessary for drug resistance. This complex, which involves protein kinase C (PKC) ε, v-raf murine sarcoma viral oncogene homolog B1 (B-RAF) and p70 S6 kinase β (S6K2), enhances the selective translation of anti-apoptotic proteins such as B-cell leukaemia/lymphoma-2 (BCL-2) and inhibitors of apoptosis protein (IAP) family members and these are able to protect multiple cancer cell types from chemotherapy-induced cell death. The Janus kinases (JAKs) are most noted for their critical roles in mediating cytokine signaling and immune responses. Here, we show that JAKs have novel functions that support their consideration as new targets in therapies aimed at reducing drug resistance. As an example, we show that the Janus kinase TYK2 is phosphorylated downstream of FGF-2 signaling and required for the full phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. Moreover, TYK2 is necessary for the induction of key anti-apoptotic proteins, such as BCL-2 and myeloid cell leukemia sequence (MCL) 1, and for the promotion of cell survival upon FGF-2. Silencing JAK1, JAK2 or TYK2 using RNA interference (RNAi) inhibits FGF2-mediated proliferation and results in the sensitization of tumor cells to chemotherapy-induced killing. These effects are independent of activation of signal transducer and activator of transcription (STAT) 1, STAT3 and STAT5A/B, the normal targets of JAK signaling. Instead, TYK2 associates with the other kinases previously implicated in FGF-2-mediated drug resistance. In light of these findings we hypothesize that TYK2 and other JAKs are important modulators of FGF-2-driven cell survival and that inhibitors of these kinases will likely improve the effectiveness of other cancer therapies
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