1,090 research outputs found
Linear and nonlinear waveguides induced by optical vortex solitons
We study, numerically and analytically, linear and nonlinear waveguides
induced by optical vortex solitons in a Kerr medium. Both fundamental and
first-order guided modes are analyzed, as well as the cases of effectively
defocusing and focusing nonlinearity.Comment: 3 pages, 3 figures, changed conten
Nonlinear theory of soliton-induced waveguides
We develop a nonlinear theory of soliton-induced waveguides that describes a
finite-amplitude probe beam guided by a spatial dark soliton in a saturable
nonlinear medium. We suggest an effective way to control the interaction of
these soliton-induced waveguides and also show that, in sharp contrast with
scalar dark solitons, the dark-soliton waveguides can attract each other and
even form stationary bound states.Comment: 3 pages, 4 figure
A mid-term astrometric and photometric study of Trans-Neptunian Object (90482) Orcus
From CCD observations of a fixed and large star field that contained the
binary TNO Orcus, we have been able to derive high-precision relative
astrometry and photometry of the Orcus system with respect to background stars.
The RA residuals of an orbital fit to the astrometric data revealed a
periodicity of 9.7+-0.3 days, which is what one would expect to be induced by
the known Orcus companion. The residuals are also correlated with the
theoretical positions of the satellite with regard to the primary. We therefore
have revealed the presence of Orcus' satellite in our astrometric measurements.
The photocenter motion is much larger than the motion of Orcus around the
barycenter, and we show here that detecting some binaries through a carefully
devised astrometric technique might be feasible with telescopes of moderate
size. We also analyzed the system's mid-term photometry to determine whether
the rotation could be tidally locked to the satellite's orbital period. We
found that a photometric variability of 9.7+-0.3 days is clear in our data, and
is nearly coincident with the orbital period of the satellite. We believe this
variability might be induced by the satellite's rotation. There is also a
slight hint for an additional small variability in the 10 hr range that was
already reported in the literature. This short-term variability would indicate
that the primary is not tidally locked and therefore the system would not have
reached a double synchronous state. Implications for the basic physical
properties of the primary and its satellite are discussed. From angular
momentum considerations we suspect that the Orcus satellite might have formed
from a rotational fission. This requires that the mass of the satellite would
be around 0.09 times that of the primary, close to the value that one derives
by using an albedo of 0.12 for the satellite and assuming equal densities for
both objects.Comment: in Press at A&
On the dynamical evolution of 2002 VE68
Minor planet 2002 VE68 was identified as a quasi-satellite of Venus shortly
after its discovery. At that time its data-arc span was only 24 days, now it is
2,947 days. Here we revisit the topic of the dynamical status of this
remarkable object as well as look into its dynamical past and explore its
future orbital evolution which is driven by close encounters with both the
Earth-Moon system and Mercury. In our calculations we use a Hermite integration
scheme, the most updated ephemerides and include the perturbations by the eight
major planets, the Moon and the three largest asteroids. We confirm that 2002
VE68 currently is a quasi-satellite of Venus and it has remained as such for at
least 7,000 yr after a close fly-by with the Earth. Prior to that encounter the
object may have already been co-orbital with Venus or moving in a classical,
non-resonant Near-Earth Object (NEO) orbit. The object drifted into the
quasi-satellite phase from an L4 Trojan state. We also confirm that, at
aphelion, dangerously close encounters with the Earth (under 0.002 AU, well
inside the Hill sphere) are possible. We find that 2002 VE68 will remain as a
quasi-satellite of Venus for about 500 yr more and its dynamical evolution is
controlled not only by the Earth, with a non-negligible contribution from the
Moon, but by Mercury as well. 2002 VE68 exhibits resonant (or near resonant)
behavior with Mercury, Venus and the Earth. Our calculations indicate that an
actual collision with the Earth during the next 10,000 yr is highly unlikely
but encounters as close as 0.04 AU occur with a periodicity of 8 years.Comment: 12 pages, 17 figures, accepted for publication in MNRAS (figures
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Mechanism of KMT5B haploinsufficiency in neurodevelopment in humans and mice
KMT5B gene; Neurodevelopment; MiceGen KMT5B; Neurodesenvolupament; RatolinsGen KMT5B; Neurodesarrollo; RatonesPathogenic variants in KMT5B, a lysine methyltransferase, are associated with global developmental delay, macrocephaly, autism, and congenital anomalies (OMIM# 617788). Given the relatively recent discovery of this disorder, it has not been fully characterized. Deep phenotyping of the largest (n = 43) patient cohort to date identified that hypotonia and congenital heart defects are prominent features that were previously not associated with this syndrome. Both missense variants and putative loss-of-function variants resulted in slow growth in patient-derived cell lines. KMT5B homozygous knockout mice were smaller in size than their wild-type littermates but did not have significantly smaller brains, suggesting relative macrocephaly, also noted as a prominent clinical feature. RNA sequencing of patient lymphoblasts and Kmt5b haploinsufficient mouse brains identified differentially expressed pathways associated with nervous system development and function including axon guidance signaling. Overall, we identified additional pathogenic variants and clinical features in KMT5B-related neurodevelopmental disorder and provide insights into the molecular mechanisms of the disorder using multiple model systems.This work was supported by LB692 Nebraska Tobacco Settlement Biomedical Research Development Program (to H.A.F.S.); The Simons Foundation Autism Research Initiative–Bridge to Independence Award SFARI 381192 (to H.A.F.S.); The A*STAR, Singapore, IAF-PP Program H17/01/a0/004 (to C.Y.L.); The Wong Boon Hock Society research program Yong Loo Lin School of Medicine (to Z.X.C.); NIH training grant 2T32GM008638-25 (L.B.); The Intramural Research Program of the National Human Genome Research Institute (to W.G.); The National Center for Advancing Translational Sciences of the NIH award number TL1TR001880 (to S.E.S.); The Eunice Kennedy Shriver National Institute of Child Health and Human Development award number HD009003-01 (to S.E.S.); Institute for Translational Medicine and Therapeutics of the Perelman School of Medicine at the University of Pennsylvania (to S.E.S.); and Swiss National Science Foundation (SNSF) grant 320020_179547 and funds from the University of Zurich Research Priority Programs (URPP) AdaBD: Adaptive Brain Circuits in Developments (to A.Rau.). F.J.K. was funded by the Deutsche Forschungsgemeinschaft grant number FOR 2488. In silico modeling was supported by the Spanish Ministerio de Ciencia e Innovación grant number PID2019-111217RB-I00 (to X.d.l.C.). This study used data from the DDD study. The DDD study presents independent research commissioned by the Health Innovation Challenge Fund (grant number HICF-1009-003). This study makes use of DECIPHER (www.deciphergenomics.org), which is funded by Wellcome (grant number 223718/Z/21/Z). See Nature PMID: 25533962 or www.ddduk.org/access.html for full acknowledgement
Essential role of CFTR in PKA-dependent phosphorylation, alkalinization, and hyperpolarization during human dperm capacitation
Mammalian sperm require to spend a limited period of time in the female reproductive tract to become competent to fertilize in a process called capacitation. It is well established that HCO3 − is essential for capacitation because it activates the atypical soluble adenylate cyclase ADCY10 leading to cAMP production, and promotes alkalinization of cytoplasm, and membrane hyperpolarization. However, how HCO3 − is transported into the sperm is not well understood. There is evidence that CFTR activity is involved in the human sperm capacitation but how this channel is integrated in the complex signaling cascades associated with this process remains largely unknown. In the present work, we have analyzed the extent to which CFTR regulates different events in human sperm capacitation. We observed that inhibition of CFTR affects HCO3 −-entrance dependent events resulting in lower PKA activity. CFTR inhibition also affected cAMP/PKA-downstream events such as the increase in tyrosine phosphorylation, hyperactivated motility, and acrosome reaction. In addition, we demonstrated for the first time, that CFTR and PKA activity are essential for the regulation of intracellular pH, and membrane potential in human sperm. Addition of permeable cAMP partially recovered all the PKA-dependent events altered in the presence of inh-172 which is consistent with a role of CFTR upstream of PKA activation.Fil: Puga Molina, Lis del Carmen. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; ArgentinaFil: Pinto, Nicolás Alejandro. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; ArgentinaFil: Torres RodrÃguez, Paulina. Universidad Nacional Autónoma de México; MéxicoFil: Romarowski, Ana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; ArgentinaFil: Vicens Sanchez, Alberto. Universidad Nacional Autónoma de México; MéxicoFil: Visconti, Pablo E.. University of Massachussets; Estados UnidosFil: Darszon, Alberto. Universidad Nacional Autónoma de México; MéxicoFil: Treviño, Claudia L.. Universidad Nacional Autónoma de México; MéxicoFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; Argentin
Perspectives on the distribution of orbits of distant Trans-Neptunian Objects
Looking at the orbits of small bodies with large semimajor axes, we are
compelled to see patterns. Some of these patterns are noted as strong
indicators of new or hidden processes in the outer Solar System, others are
substantially generated by observational biases, and still others may be
completely overlooked. We can gain insight into the current and past structure
of the outer Solar System through a careful examination of these orbit
patterns. In this chapter, we discuss the implications of the observed orbital
distribution of distant trans-Neptunian objects (TNOs). We start with some
cautions on how observational biases must affect the known set of TNO orbits.
Some of these biases are intrinsic to the process of discovering TNOs, while
others can be reduced or eliminated through careful observational survey
design. We discuss some orbital element correlations that have received
considerable attention in the recent literature. We examine the known TNOs in
the context of the gravitational processes that the known Solar System induces
in orbital distributions. We discuss proposed new elements of the outer Solar
System, posited ancient processes, and the types of TNO orbital element
distributions that they predict to exist. We conclude with speculation.Comment: 15 pages, 3 figures, to appear in The Trans-Neptunian Solar System
(Chapter 3
Stability of narrow beams in bulk Kerr-type nonlinear media
We consider (2+1)-dimensional beams, whose transverse size may be comparable
to or smaller than the carrier wavelength, on the basis of an extended version
of the nonlinear Schr\"{o}dinger equation derived from the Maxwell`s equations.
As this equation is very cumbersome, we also study, in parallel to it, its
simplified version which keeps the most essential term: the term which accounts
for the {\it nonlinear diffraction}. The full equation additionally includes
terms generated by a deviation from the paraxial approximation and by a
longitudinal electric-field component in the beam. Solitary-wave stationary
solutions to both the full and simplified equations are found, treating the
terms which modify the nonlinear Schr\"{o}dinger equation as perturbations.
Within the framework of the perturbative approach, a conserved power of the
beam is obtained in an explicit form. It is found that the nonlinear
diffraction affects stationary beams much stronger than nonparaxiality and
longitudinal field. Stability of the beams is directly tested by simulating the
simplified equation, with initial configurations taken as predicted by the
perturbation theory. The numerically generated solitary beams are always stable
and never start to collapse, although they display periodic internal
vibrations, whose amplitude decreases with the increase of the beam power.Comment: 7 pages, 6 figures Accepted for publication in PR
Phenotypic microarrays suggest Escherichia coli ST131 is not a metabolically distinct lineage of extra-intestinal pathogenic E. coli
Extraintestinal pathogenic E. coli (ExPEC) are the major aetiological agent of urinary tract infections (UTIs) in humans. The emergence of the CTX-M producing clone E. coli ST131 represents a major challenge to public health worldwide. A recent study on the metabolic potential of E. coli isolates demonstrated an association between the E. coli ST131 clone and enhanced utilisation of a panel of metabolic substrates. The studies presented here investigated the metabolic potential of ST131 and other major ExPEC ST isolates using 120 API test reagents and found that ST131 isolates demonstrated a lower metabolic activity for 5 of 120 biochemical tests in comparison to non-ST131 ExPEC isolates. Furthermore, comparative phenotypic microarray analysis showed a lack of specific metabolic profile for ST131 isolates countering the suggestion that these bacteria are metabolically fitter and therefore more successful human pathogens
Urban land planning: The role of a Master Plan in influencing local temperatures
Land use planning (LUP) is central for managing issues related to climatic variation in urban environments. However, Master Plans (MPs) usually do not include climatic aspects, and few studies have addressed climate change at the urban scale, especially in developing countries. This paper proposes a framework with ten categories for assessment of climatic variation in urban LUP. Each category comprises attributes that describe a complex of relationships in influencing local temperature variations. They are analyzed for the case of the Master Plan of Porto Alegre (MPPA), the Southernmost metropolis of Brazil. It is concluded that the MPPA is strongly grounded in climate-related land and zoning coordination, but exhibits weaknesses in building, cartographical and social aspects considered synergistically relevant for tackling problems related to urban climate variation. Furthermore, the MPPA does not contain provisions related to monitoring of local climate and greenhouse gases (GHG) emissions and it is ineffective for improving energy efficiency. Specific MPPA failures stemming from these weaknesses include: an increase of 21.79% in the city's urbanized area from 1986 to 2011 to accommodate a similar increase in population, with significant horizontal sprawl; average temperature rise of 0.392. °C from 1991-2000 to 2001-2010, with statistically significant increases in temperature found since 1931; significant vehicle traffic increases, especially since 2007. From these findings, it is possible to conclude that the MPPA does not offer answers to all the imbalances related to land use, and therefore gives insufficient support to tackle the issue of rising temperatures
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