2,257 research outputs found
Relevance of unilateral and bilateral sexual polyploidization in relation to intergenomic recombination and introgression in Lilium species hybrids
Sexual polyploids were induced in diploid (2n = 2x = 24) interspecific F1 hybrids of Longiflorum × Asiatic (LA) and Oriental × Asiatic (OA) Lilium hybrids by backcrossing to Asiatic (AA) parents as well as by sib-mating of the F1 LA hybrids. A majority of the BC1 progenies were triploid and the progenies from sib-mating were tetraploid or near tetraploids. Genomic in situ hybridization (GISH) technique was applied to assess the intergenomic recombination in the BC1 populations of LA and OA hybrids obtained after unilateral sexual polyploidization. A total of 63 LA (LA × AA and AA × LA) and 53 OA hybrids were analysed. LA hybrids were originated through the functioning of 2n gametes either as 2n eggs or 2n pollen while those of OA hybrids originated through functional 2n pollen of diploid OA genotype. In both type of crosses, a majority of the progenies had originated through First Division Restitution (FDR) mechanism of functional 2n gamete either with or without a cross over. However, there were nine LA- and four OA-genotypes where Indeterminate Meiotic Restitution (IMR) was the mechanism of 2n gamete formation. Based on GISH, total amount of introgression of Longiflorum and Oriental genome into Asiatic genome was determined. Most of the BC progenies exhibited recombination and the amount of recombination was higher in LA hybrids as compared to OA hybrids. Intergenomic recombination was also determined cytologically in the 16 plants of sib-mated LA hybrids where both parents had contributed 2n gametes. Based on these results the nature of interspecific lily hybrids obtained from uni- and bilateral sexual polyploidization leading to allotriploid and allotetraploid formation is discussed in the context of introgression and intergenomic recombinatio
Human metapneumovirus: Mechanisms and molecular targets used by the virus to avoid the immune system
Indexación: Scopus.This work was supported by Comisión Nacional de Investigación Científica y Tecnolígica (CONICYT) N◦21151028 and FONDECYT (N◦1070352 and N◦1170964) and the Millennium Institute on Immunology and Immunotherapy (P09/016-F).Human metapneumovirus (hMPV) is a respiratory virus, first reported the year 2001. Since then, it has been described as one of the main etiological agents that causes acute lower respiratory tract infections (ALRTIs), which is characterized by symptoms such as bronchiolitis, wheezing and coughing. Susceptible population to hMPV-infection includes newborn, children, elderly and immunocompromised individuals. This viral agent is a negative-sense, single-stranded RNA enveloped virus, that belongs to the Pneumoviridae family and Metapneumovirus genus. Early reports-previous to 2001-state several cases of respiratory illness without clear identification of the responsible pathogen, which could be related to hMPV. Despite the similarities of hMPV with several other viruses, such as the human respiratory syncytial virus or influenza virus, mechanisms used by hMPV to avoid the host immune system are still unclear. In fact, evidence indicates that hMPV induces a poor innate immune response, thereby affecting the adaptive immunity. Among these mechanisms, is the promotion of an anergic state in T cells, instead of an effective polarization or activation, which could be induced by low levels of cytokine secretion. Further, the evidences support the notion that hMPV interferes with several pattern recognition receptors (PRRs) and cell signaling pathways triggered by interferon-associated genes. However, these mechanisms reported in hMPV are not like the ones reported for hRSV, as the latter has two non-structural proteins that are able to inhibit these pathways. Several reports suggest that viral glycoproteins, such as G and SH, could play immune-modulator roles during infection. In this work, we discuss the state of the art regarding the mechanisms that underlie the poor immunity elicited by hMPV. Importantly, these mechanisms will be compared with those elicited by other common respiratory viruses. © 2018 Frontiers Media S.A. All rights reserved.https://www.frontiersin.org/articles/10.3389/fimmu.2018.02466/ful
Minimal H\"older regularity implying finiteness of integral Menger curvature
We study two families of integral functionals indexed by a real number . One family is defined for 1-dimensional curves in and the other one
is defined for -dimensional manifolds in . These functionals are
described as integrals of appropriate integrands (strongly related to the
Menger curvature) raised to power . Given we prove that
regularity of the set (a curve or a manifold), with implies finiteness of both curvature functionals
( in the case of curves). We also show that is optimal by
constructing examples of functions with graphs of infinite
integral curvature
Human gait identification using persistent homology
This paper shows an image/video application using topological invariants for human gait recognition. Using a background subtraction approach, a stack of silhouettes is extracted from a subsequence and glued through their gravity centers, forming a 3D digital image I. From this 3D representation, the border simplicial complex ∂ K(I) is obtained. We order the triangles of ∂ K(I) obtaining a sequence of subcomplexes of ∂ K(I). The corresponding filtration F captures relations among the parts of the human body when walking. Finally, a topological gait signature is extracted from the persistence barcode according to F. In this work we obtain 98.5% correct classification rates on CASIA-B database
Evidence for internal field in graphite: A conduction electron spin resonance study
We report conduction electron spin resonance measurements performed on highly
oriented pyrolitic graphite samples between 10 K and 300 K using S (f = 4 GHz),
X (f = 9.4 GHz), and Q (f = 34.4 GHz) microwave bands for the external
dc-magnetic field applied parallel (H || c) and perpendicular (H perp c) to the
sample hexagonal c-axis. The results obtained in the H || c geometry are
interpreted in terms of the presence of an effective internal
ferromagnetic-like field Heff-int(T,H) that increases as the temperature
decreases and the applied dc-magnetic field increases. We associate the
occurrence of the Heff-int(T,H) with the field-induced metal-insulator
transition in graphite and discuss its origin in the light of relevant
theoretical models.Comment: 10 pages (tex), 5 figures (ps
Una aproximación hacia la equidad en las penas en materia de niños, niñas y adolescentes imputados por la ley penal en Mendoza
Desde la presente investigación se trató de corroborar la medida en la que los factores de riesgo asociados a la deprivación socio-cultural en los menores, inciden en la comisión de delitos graves. Con este propósito, en la primer etapa del trabajo, se analizó la totalidad de casos en los que menores de entre 16 y 18 años de edad, cometieron homicidios en la provincia de Mendoza, entre los años 2003 y 2007. En una segunda etapa de trabajo, se analizó también, una muestra de casos con características similares, pero esta vez, de jóvenes que cometieron el delito de abuso sexual.
Correction: Martínez-González, M.A. et al. Transferability of the Mediterranean Diet to Non-Mediterranean Countries. What Is and What Is Not the Mediterranean Diet. Nutrients 2017, 9, 1226
The authors have requested that the following changes be made to their paper [1]
Leptogenesis and Low-energy Observables
We relate leptogenesis in a class of theories to low-energy experimental
observables: quark and lepton masses and mixings. With reasonable assumptions
motivated by grand unification, one can show that the CP-asymmetry parameter
takes a universal form. Furthermore the dilution mass is related to the light
neutrino masses. Overall, these models offer a natural explanation for a lepton
asymmetry in the early universe.Comment: 10 pages, revised discussion on light neutrino masse
Vertical transport and electroluminescence in InAs/GaSb/InAs structures: GaSb thickness and hydrostatic pressure studies
We have measured the current-voltage (I-V) of type II InAs/GaSb/InAs double
heterojunctions (DHETs) with 'GaAs like' interface bonding and GaSb thickness
between 0-1200 \AA. A negative differential resistance (NDR) is observed for
all DHETs with GaSb thickness 60 \AA below which a dramatic change in the
shape of the I-V and a marked hysteresis is observed. The temperature
dependence of the I-V is found to be very strong below this critical GaSb
thickness. The I-V characteristics of selected DHETs are also presented under
hydrostatic pressures up to 11 kbar. Finally, a mid infra-red
electroluminescence is observed at 1 bar with a threshold at the NDR valley
bias. The band profile calculations presented in the analysis are markedly
different to those given in the literature, and arise due to the positive
charge that it is argued will build up in the GaSb layer under bias. We
conclude that the dominant conduction mechanism in DHETs is most likely to
arise out of an inelastic electron-heavy-hole interaction similar to that
observed in single heterojunctions (SHETs) with 'GaAs like' interface bonding,
and not out of resonant electron-light-hole tunnelling as proposed by Yu et al.
A Zener tunnelling mechanism is shown to contribute to the background current
beyond NDR.Comment: 8 pages 12 fig
From aid to sustainable trade: driving competitive horticulture sector development : A quick scan of the horticulture sector
This report provides an overview of how the Kenyan horticulture sector performs in three analytical domains: the robustness of the supply chains, the reliability of institutional governance and the resilience of the innovation system. Analysis is by literature review, stakeholder interviews and a validation workshop guided by a SWOT framework to identify strengths, weaknesses, opportunities and threats. The findings inform the existing opportunities and challenges that potentially impede growth in the sector. The report is a first step towards documenting and sharing insights that support the move towards a more Robust, Reliable and Resilient (3R) horticulture sector. The findings and recommendations presented will guide policy engagement and action in the transition of Dutch government bilateral engagement in Kenya from development aid–support to a trade approach in the agricultural sector, with a focus on partnering opportunities to drive competitive market-oriented horticulture sector development that attracts investments
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