2,537 research outputs found
Identification of an Efficient Gene Expression Panel for Glioblastoma Classification.
We present here a novel genetic algorithm-based random forest (GARF) modeling technique that enables a reduction in the complexity of large gene disease signatures to highly accurate, greatly simplified gene panels. When applied to 803 glioblastoma multiforme samples, this method allowed the 840-gene Verhaak et al. gene panel (the standard in the field) to be reduced to a 48-gene classifier, while retaining 90.91% classification accuracy, and outperforming the best available alternative methods. Additionally, using this approach we produced a 32-gene panel which allows for better consistency between RNA-seq and microarray-based classifications, improving cross-platform classification retention from 69.67% to 86.07%. A webpage producing these classifications is available at http://simplegbm.semel.ucla.edu
Validation of an automated spectrophotometric method to dose SO2 in vinegar
Sulfur dioxide and sulfites are considered allergens, and their levels in food are regulated by law. The method used to dose free and total sulfites in vinegar is the Ripper method which consists of a direct titration with iodine using starch as an indicator. The Ripper method involves long and elaborate processes, requires excellent operator skills, and has long analysis times. This work validated an enzymatic method performed by an automatized spectroscopic apparatus. Method linearity, applicability range, minimum detection limit, the limit of quantification, and repeatability were demonstrated. Therefore, the enzymatic method performed by an automatized spectroscopic apparatus can be used to detect SO2 in vinegar
The Stationary Phase Method for a Wave Packet in a Semiconductor Layered System. The applicability of the method
Using the formal analysis made by Bohm in his book, {\em "Quantum theory"},
Dover Publications Inc. New York (1979), to calculate approximately the phase
time for a transmitted and the reflected wave packets through a potential
barrier, we calculate the phase time for a semiconductor system formed by
different mesoscopic layers. The transmitted and the reflected wave packets are
analyzed and the applicability of this procedure, based on the stationary phase
of a wave packet, is considered in different conditions. For the applicability
of the stationary phase method an expression is obtained in the case of the
transmitted wave depending only on the derivatives of the phase, up to third
order. This condition indicates whether the parameters of the system allow to
define the wave packet by its leading term. The case of a multiple barrier
systems is shown as an illustration of the results. This formalism includes the
use of the Transfer Matrix to describe the central stratum, whether it is
formed by one layer (the single barrier case), or two barriers and an inner
well (the DBRT system), but one can assume that this stratum can be comprise of
any number or any kind of semiconductor layers.Comment: 15 pages, 4 figures although figure 4 has 5 graph
Family well-being during the COVID-19 lockdown in Italy: Gender differences and solidarity networks of care
During the COVID-19 pandemic, families experienced new challenges related to reorganizing living spaces and the need to renegotiate domestic and care roles. This paper aims to understand how Italian families have reacted to this situation with respect to psychological well-being, the management of domestic and care activities and solidarity networks of care. The participants were 560 Italian subjects who reported having a parental role. The protocol included a measure of well-being (the General Health Questionnaire-12) and some questions related to the time dedicated to domestic activities or to caring for people, the perception of conflict within the family and solidarity networks of care. The data underline how mothers continued to devote more time to home and care activities than fathers, despite the presence of both partners at home during the lockdown. The results also indicate that mothers participated to a greater extent than fathers in solidarity activities, confirming that this dimension is linked to gender. Furthermore, fathers and mothers perceived a lower condition of well-being in relation to the pre-pandemic period
The collapse of the Morandi bridge in Genoa on 14 august 2018: A collective traumatic event and its emotional impact linked to the place and loss of a symbol
The collapse of the Morandi bridge in Italy, which took place in the summer of 2018, has had enormous emotional, economic, and social consequences for the inhabitants of the area, which are felt throughout the world. As seen in the literature, collective traumatic events increase the experience of insecurity and paranoia, thus increasing the perception of vulnerability. The present work aims to bring out the emotions most experienced by the participants connected to the traumatic event in question, paying attention to the possible solutions to be proposed to local stakeholders from a sustainability perspective, this way favouring community empowerment. The research, carried out with the photovoice technique, involved 30 young adults residing in areas near the event. The results illustrate how the participants experienced mainly feelings of emptiness, vulnerability, and fear as well as anger, despair, and mistrust of the institutions. It was also stressed that the economic and structural hardships hit the inhabitants hard. There have been many concrete solutions identified by the participants: creating a support network, supporting the local economy, and keeping the memory alive. The research and application implications underline the importance of using photovoice within community interventions, a tool that facilitates awareness and active citizenship
On a new theoretical framework for RR Lyrae stars I: the metallicity dependence
We present new nonlinear, time-dependent convective hydrodynamical models of
RR Lyrae stars computed assuming a constant helium-to-metal enrichment ratio
and a broad range in metal abundances (Z=0.0001--0.02). The stellar masses and
luminosities adopted to construct the pulsation models were fixed according to
detailed central He burning Horizontal Branch evolutionary models. The
pulsation models cover a broad range in stellar luminosity and effective
temperatures and the modal stability is investigated for both fundamental and
first overtones. We predict the topology of the instability strip as a function
of the metal content and new analytical relations for the edges of the
instability strip in the observational plane. Moreover, a new analytical
relation to constrain the pulsation mass of double pulsators as a function of
the period ratio and the metal content is provided. We derive new
Period-Radius-Metallicity relations for fundamental and first-overtone
pulsators. They agree quite well with similar empirical and theoretical
relations in the literature. From the predicted bolometric light curves,
transformed into optical (UBVRI) and near-infrared (JHK) bands, we compute the
intensity-averaged mean magnitudes along the entire pulsation cycle and, in
turn, new and homogenous metal-dependent (RIJHK) Period-Luminosity relations.
Moreover, we compute new dual and triple band optical, optical--NIR and NIR
Period-Wesenheit-Metallicity relations. Interestingly, we find that the optical
Period-W(V,B-V) is independent of the metal content and that the accuracy of
individual distances is a balance between the adopted diagnostics and the
precision of photometric and spectroscopic datasets.Comment: 51 pages, 20 figures, 9 tables, accepted for publication on Ap
The Carina Project. VI. The helium burning variable stars
We present new optical (BVI) time-series data for the evolved variable stars
in the Carina dwarf spheroidal galaxy. The quality of the data and the
observing strategy allowed us to identify 14 new variable stars. Eight out of
the 14 are RR Lyrae (RRL) stars, four are Anomalous Cepheids (ACs) and two are
geometrical variables. Comparison of the period distribution for the entire
sample of RRLs with similar distributions in nearby dSphs and in the Large
Magellanic Cloud indicates that the old stellar populations in these systems
share similar properties. This finding is also supported by the RRL
distribution in the Bailey diagram. On the other hand, the period distribution
and the Bailey diagram of ACs display significant differences among the above
stellar systems. This evidence suggests that the properties of intermediate-age
stellar populations might be affected both by environmental effects and
structural parameters. We use the BV Period--Wesenheit (PW) relation of RRLs
together with evolutionary prescriptions and find a true distance modulus of
20.09+/-0.07(intrinsic)+/-0.1(statistical) mag that agrees quite well with
similar estimates available in the literature. We identified four peculiar
variables. Taking into account their position in the Bailey diagram and in the
BV PW relation, two of them (V14, V149) appear to be candidate ACs, while two
(V158, V182) might be peculiar RRLs. In particular, the variable V158 has a
period and a V-band amplitude very similar to the low-mass RRL
---RRLR-02792---recently identified by Pietrzynski at al. (2012) in the
Galactic bulge.Comment: Accepted for publication in ApJ, publication date September 20, 2013.
31 pages, 7 figure, 3 tables. Figs. 3 and 4 corrected, references added,
minor correction
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
Asymmetric MSM sub-bandgap all-silicon photodetector with low dark current
Design, fabrication, and characterization of an asymmetric metal-semiconductor-metal photodetector, based on internal photoemission effect and integrated into a silicon-on-insulator waveguide, are reported. For this photodetector, a responsivity of 4.5 mA/W has been measured at 1550 nm, making it suitable for power monitoring applications. Because the absorbing metal is deposited strictly around the vertical output facet of the waveguide, a very small contact area of about 3 ”m2 is obtained and a transit-time-limited bandwidth of about 1 GHz is demonstrated. Taking advantage of this small area and electrode asymmetry, a significant reduction in the dark current (2.2 nA at -21 V) is achieved. Interestingly, applying reverse voltage, the photodetector is able to tune its cut-off wavelength, extending its range of application into the MID infrared regime
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