949 research outputs found
Genetic Polymorphism in Evolving Population
We present a model for evolving population which maintains genetic
polymorphism. By introducing random mutation in the model population at a
constant rate, we observe that the population does not become extinct but
survives, keeping diversity in the gene pool under abrupt environmental
changes. The model provides reasonable estimates for the proportions of
polymorphic and heterozygous loci and for the mutation rate, as observed in
nature
PLANT: A Method for Detecting Changes of Slope in Noisy Trajectories
Time traces obtained from a variety of biophysical experiments contain valuable information on underlying processes occurring at the molecular level. Accurate quantification of these data can help explain the details of the complex dynamics of biological systems. Here, we describe PLANT (Piecewise Linear Approximation of Noisy Trajectories), a segmentation algorithm that allows the reconstruction of time-trace data with constant noise as consecutive straight lines, from which changes of slopes and their respective durations can be extracted. We present a general description of the algorithm and perform extensive simulations to characterize its strengths and limitations, providing a rationale for the performance of the algorithm in the different conditions tested. We further apply the algorithm to experimental data obtained from tracking the centroid position of lymphocytes migrating under the effect of a laminar flow and from single myosin molecules interacting with actin in a dual-trap force-clamp configuration.The authors gratefully acknowledge financial support fromthe European Commission (FP7-ICT-2011-7, grant number 288263), Erasmus Mundus Doctorate Program Europhoton-ics (grant number 159224-1-2009-1-FR-ERA MUNDUS-EMJD), Spanish Ministry of Economy and Competi-tiveness (“Severo Ochoa” Programme for Centres of Excellence in Research & Development SEV-2015-0522,and FIS2014-56107-R grants), Generalitat de Catalunyathrough the CERCA program, Italian Ministry of Uni-versity and Research (FIRB “Futuro in Ricerca” 2013grant n. RBFR13V4M2 and Flagship Project NANOMAX),Fundaci ́o Privada CELLEX (Barcelona), Ente Cassa diRisparmio di Firenze, Human Frontier Science Program (GARGP0027/2012) and LaserLab Europe 4 (GA 654148). C.M.acknowledges funding from the Spanish Ministry of Econ-omy and Competitiveness (MINECO) and the EuropeanSocial Fund (ESF) through the Ram ́on y Cajal program 2015(RYC-2015-17896).Peer ReviewedPostprint (author's final draft
MAPS-SNMA ShaD.O.w D.O. Day Rowan SOM Pipeline Program: A Pilot Study
Prior to being a medical student, a majority of pre-medical students have not encountered the course load intensity, academic rigor, and time management required by a medical school curriculum. Diversifying the workforce has been shown to have benefits, especially at the micro or patient level, since having racial or ethnic concordance between providers and patients has been associated with increased levels of satisfaction and improvements in certain clinical outcomes. The number of MDs increased to 841,321 or 91.8% versus 72,961 DOs or 8.0% creating the need for minorities to be knowledgeable of both MD and DO paths to becoming a physician. To provide more knowledge of osteopathic medicine and osteopathic physicians, the Minority Association of Premedical Students (M.A.P.S.) and the the Student National Medical Association (S.N.M.A.) of Rowan University School of Osteopathic Medicine have implemented a ShaDOw DO Day program for the graduate students of Rowan University Graduate School of Biomedical Sciences. The ShaDOw DO Day program will give MAPS students the opportunity to witness the resilience, discipline, and motivation that successful medical students possess.This program will also provide MAPS students with the opportunity to explore a potential career in medicine. Students will gain a perspective on osteopathic principles and osteopathic manipulative medicine. Participants of the program will also be introduced to the quality education an osteopathic medical school such as RowanSOM instills in its students to produce competent and compassionate physicians. Therefore, it is imperative that graduate students learn from medical students to increase their knowledge of osteopathic medicine. To analyze the effectiveness of this program, pre-assessment and post-assessment surveys were given to the participants. Overall, an increase in the understanding of osteopathic medicine and consideration of a career in a health profession and/or medicine was observed demonstrating both the need and success of our program initiative
Controlling the balance between remote, pinhole, and van der Waals epitaxy of Heusler films on graphene/sapphire
Remote epitaxy on monolayer graphene is promising for synthesis of highly
lattice mismatched materials, exfoliation of free-standing membranes, and
re-use of expensive substrates. However, clear experimental evidence of a
remote mechanism remains elusive. In many cases, due to contaminants at the
transferred graphene/substrate interface, alternative mechanisms such as
pinhole-seeded lateral epitaxy or van der Waals epitaxy can explain the
resulting exfoliatable single-crystalline films. Here, we find that growth of
the Heusler compound GdPtSb on clean graphene on sapphire substrates produces a
30 degree rotated epitaxial superstructure that cannot be explained by pinhole
or van der Waals epitaxy. With decreasing growth temperature the volume
fraction of this 30 degree domain increases compared to the direct epitaxial 0
degree domain, which we attribute to slower surface diffusion at low
temperature that favors remote epitaxy, compared to faster surface diffusion at
high temperature that favors pinhole epitaxy. We further show that careful
graphene/substrate annealing () and consideration of the
film/substrate vs film/graphene lattice mismatch are required to obtain epitaxy
to the underlying substrate for a variety of other Heusler films, including
LaPtSb and GdAuGe. The 30 degree rotated superstructure provides a possible
experimental fingerprint of remote epitaxy since it is inconsistent with the
leading alternative mechanisms
Epitaxy, exfoliation, and strain-induced magnetism in rippled Heusler membranes
Single-crystalline membranes of functional materials enable the tuning of
properties via extreme strain states; however, conventional routes for
producing membranes require the use of sacrificial layers and chemical
etchants, which can both damage the membrane and limit the ability to make them
ultrathin. Here we demonstrate the epitaxial growth of the cubic Heusler
compound GdPtSb on graphene-terminated AlO substrates. Despite the
presence of the graphene interlayer, the Heusler films have epitaxial registry
to the underlying sapphire, as revealed by x-ray diffraction, reflection high
energy electron diffraction, and transmission electron microscopy. The weak Van
der Waals interactions of graphene enable mechanical exfoliation to yield
free-standing GdPtSb membranes, which form ripples when transferred to a
flexible polymer handle. Whereas unstrained GdPtSb is antiferromagnetic,
measurements on rippled membranes show a spontaneous magnetic moment at room
temperature, with a saturation magnetization of 5.2 bohr magneton per Gd.
First-principles calculations show that the coupling to homogeneous strain is
too small to induce ferromagnetism, suggesting a dominant role for strain
gradients. Our membranes provide a novel platform for tuning the magnetic
properties of intermetallic compounds via strain (piezomagnetixm and
magnetostriction) and strain gradients (flexomagnetism)
The Off State of GX 339-4
We report BeppoSAX and optical observations of the black hole candidate GX
339-4 during its X-ray `off' state in 1999. The broad-band (0.8-50 keV) X-ray
emission can be fitted by a single power law with spectral index, \alpha ~1.6.
The observed luminosity is 6.6e33 erg s^{-1} in the 0.5-10 keV band, which is
at the higher end of the flux distribution of black hole soft X-ray transients
in quiescence, comparable to that seen in GS 2023+338 and 4U 1630-47. An
optical observation just before the BeppoSAX observation shows the source to be
very faint at these wavelengths as well (B=20.1, V=19.2). By comparing with
previously reported `off' and low states (LS), we conclude that the `off' state
is actually an extension of the LS, i.e. a LS at lower intensities. We propose
that accretion models such as the advection-dominated accretion flows are able
to explain the observed properties in such a state.Comment: Accepted for publication in MNRA
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