1,418 research outputs found
Sperm quality parameters of Iberian toothcarp (Aphanius iberus) and Valencia toothcarp (Valencia hispanica): new conservation tools from a gamete perspective
[EN] The sensitive state of conservation of several endemic fish species such as Iberian toothcarp (Aphanius iberus) and Valencia toothcarp (Valencia hispanica) has led governments to consider the implementation of conservation measures to preserve their populations. However, limited knowledge about the reproductive biology of these species makes it necessary to investigate different aspects of their reproductive cycle. In this sense, the main objectives of this work were i) to advance knowledge of the breeding biology of both species, and ii) to develop protocols for the conservation of gametes for the future management and conservation.
During the spring of 2019 a temporal series of samplings were carried out in different places in the Comunitat Valenciana. Sperm samples were collected and sperm motion parameters were assessed for the first time in both species. Kinetic patterns were similar showing high motility and velocity values during the first 30 s, and a rapid decrease from that point. At the same time, an in-depth morphometric analysis was carried out using computer-assisted sperm analysis software. Spermatozoa from A. iberus and V. hispanica showed similar sizes and shapes to other external fertilizers belonging to Cyprinodontiformes, with small spherical heads, uniflagellated and without acrosomes.
In addition, a new cryopreservation protocol was designed for cryobanking the sperm of these threatened species. Cryopreserved samples showed lower motility than fresh samples but reaching acceptable percentages of motile cells after thawing of around 20 and 25% (A. iberus and V. hispanica, respectively). This study is the first of its kind to successfully achieve gamete cryopreservation of these two endemic and endangered species from the Iberian Peninsula, providing new and useful tools to complement the management and conservation programs that are being developed for both species.This project has received funding from the Generalitat Valenciana (GV; Valencia, Spain) under the "Subvenciones para la realizacion de proyectos de I+D+I desarrollados por grupos de investigacion emergentes (GV/2019/130)". VG has a postdoc grant from the Ministerio de Economia, Industria y Competitividad (MINECO; Madrid, Spain) under the project IJCI-2017-34200. We would like to thank all the technicians of the CCEDCV for their work and effort during the samplings, specially to J. Velazquez, J. Hernandez and A. Pradillo.Blanes-GarcĂa, M.; Risueño, P.; PĂ©rez Igualada, LM.; Asturiano, JF.; Gallego Albiach, V. (2021). Sperm quality parameters of Iberian toothcarp (Aphanius iberus) and Valencia toothcarp (Valencia hispanica): new conservation tools from a gamete perspective. Aquaculture. 530:1-9. https://doi.org/10.1016/j.aquaculture.2020.735819S1953
Modeling the connection between primary and metastatic tumors
We put forward a model for cancer metastasis as a migration phenomenon
between tumor cell populations coexisting and evolving in two different habitats. One
of them is a primary tumor and the other one is a secondary or metastatic tumor. The
evolution of the different cell phenotype populations in each habitat is described by
means of a simple quasispecies model allowing for a cascade of mutations between
the different phenotypes in each habitat. The cell migration event is supposed to be
unidirectional and take place continuously in time. The possible clinical outcomes
of the model depending on the parameter space are analyzed and the effect of the
resection of the primary tumor is studied
Analysis of tooth mark patterns on bone remains caused by wolves (Canis lupus) and domestic dogs (Canis lupus familiaris) for taxonomic identification: A scoping review focused on their value as a forensic tool.
The interaction between canids and humans is not free of conflicts. In Europe, wolves and dogs' attacks on domestic animals cause social and financial damages. The governments spend significant sums in compensation payments. Some of the allegations of wolf attacks on livestock may be false or difficult to prove. The insufficient expertise and unreliable methods used during the investigations often make it difficult to achieve a successful perpetrator identification, which leads to the stigmatization of this species and wrong paid compensations. Comparative studies of wolf and dog bite marks and tooth marks, to identify a potential aggressor agent, are very limited. In our study, 12,120 records were reviewed and only 16 of them fulfilled the search criteria set by the authors. Only one article carried out, exclusively, a comparison of wolf and dog bite mark patterns. These studies are commonly used in archaeological, paleontological and taphonomic contexts, but not in forensics. Despite the notable advances in bite mark analysis, most studies were carried out comparing bite marks from wolves and/or dogs and taxa belonging to other families. Currently, in forensic context, there is inconclusive evidence to certainly distinguish if the cause of death was created by wolves or domestic dogs using the forensic analysis of tooth/bite marks patterns from both canids (beyond any reasonable doubt). New and complementary forensic tools must be developed to differentiate between these two subspecies with a higher degree of certainty. Forensic veterinary odontology could play an important role in fulfilling this goal. The aim of the present work is to review and evaluate the studies on the identification of tooth marks on bone remains caused by two subspecies belonging to the same genus, wolves and domestic dogs
Stability of vortices in rotating taps: a 3d analysis
We study the stability of vortex-lines in trapped dilute gases subject to
rotation. We solve numerically both the Gross-Pitaevskii and the Bogoliubov
equations for a 3d condensate in spherically and cilyndrically symmetric
stationary traps, from small to very large nonlinearities. In the stationary
case it is found that the vortex states with unit and charge are
energetically unstable. In the rotating trap it is found that this energetic
instability may only be suppressed for the vortex-line, and that the
multicharged vortices are never a local minimum of the energy functional, which
implies that the absolute minimum of the energy is not an eigenstate of the
operator, when the angular speed is above a certain value, .Comment: 10 pages, 7 figures in EPS forma
Structural, mechanical and electronic properties of two-dimensional structure of III-arsenide (1 1 1) binary compounds: An ab-initio study
Structural, mechanical and electronic properties of two-dimensional single-layer hexagonal structures in the (1 1 1) crystal plane of IIIAs-ZnS systems (III = B, Ga and In) are studied by first-principles calculations based on density functional theory (DFT). Elastic and phonon dispersion relation display that 2D h-IIIAs systems (III = B, Ga and In) are both mechanical and dynamically stable. Electronic structures analysis show that the semiconducting nature of the 3D-IIIAs compounds is retained by their 2D single layer counterpart. Furthermore, density of states reveals the influence of Ï and Ï bonding in the most stable geometry (planar or buckled) for 2D h-IIIAs systems. Calculations of elastic constants show that the Young's modulus, bulk modulus and shear modulus decrease for 2D h-IIIAs binary compounds as we move down on the group of elements of the periodic table. In addition, as the bond length between the neighboring cation-anion atoms increases, the 2D h-IIIAs binary compounds display less stiffness and more plasticity. Our findings can be used to understand the contribution of the Ï and Ï bonding in the most stable geometry (planar o buckled) for 2D h-IIIAs systems. Structural and electronic properties of h-IIIAs systems as a function of the number of layers have been also studied. It is shown that h-BAs keeps its planar geometry while both h-GAs and h-InAs retained their buckled ones obtained by their single layers. Bilayer h-IIIAs present the same bandgap nature of their counterpart in 3D. As the number of layers increase from 2 to 4, the bandgap width for layered h-IIIAs decreases until they become semimetal or metal. Interestingly, these results are different to those found for layered h-GaN. The results presented in this study for single and few-layer h-IIIAs structures could give some physical insights for further theoretical and experimental studies of 2D h-IIIV-like systems
Manic episode after treatment with ventriculoperitoneal shunting due to obstructive hydrocephalus with corpus callosal signal changes: a case report
The interplay of blood flow and temperature in regional hyperthermia: a mathematical approach
In recent decades, hyperthermia has been used to raise oxygenation levels in tumours undergoing other therapeutic modalities, of which radiotherapy is the most prominent one. It has been hypothesized that oxygenation increases would come from improved blood flow associated with vasodilation. However, no test has determined whether this is a relevant assumption or other mechanisms might be acting. Additionally, since hyperthermia and radiotherapy are not usually co-administered, the crucial question arises as to how temperature and perfusion in tumours will change during and after hyperthermia. Overall, it would seem necessary to find a research framework that clarifies the current knowledge, delimits the scope of the different effects and guides future research. Here, we propose a simple mathematical model to account for temperature and perfusion dynamics in brain tumours subjected to regional hyperthermia. Our results indicate that tumours in well-perfused organs like the brain might only reach therapeutic temperatures if their vasculature is highly disrupted. Furthermore, the characteristic times of return to normal temperature levels are markedly shorter than those required to deliver adjuvant radiotherapy. According to this, a mechanistic coupling of perfusion and temperature would not explain any major oxygenation boost in brain tumours immediately after hyperthermia
Towards the growth of Cu2ZnSn1 xGexS4 thin films by a single-stage process: Effect of substrate temperature and composition
9 pĂĄgs.; 7 figs.; 2 tabs.Cu2ZnSn1-xGexS4 (CZTGS) thin films prepared by flash evaporation of a Zn-rich Cu2ZnSn0.5Ge0.5S4 bulk compound in powder form, and a subsequent thermal annealing in S containing Ar atmosphere are studied. The effect of the substrate temperature during evaporation and the initial composition of the precursor powder on the growth mechanism and properties of the final CZTGS thin film are investigated. The microstructure of the films and elemental depth profiles depend strongly on the growth conditions used. Incorporation of Ge into the Cu2ZnSnS4 lattice is demonstrated by the shift of the relevant X-ray diffraction peaks and Raman vibrational modes towards higher diffraction angles and frequencies respectively. A Raman mode at around 348-351 cm-1 is identified as characteristic of CZTGS alloys for x = [Ge]/([Sn]+[Ge]) = 0.14-0.30. The supply of Ge enables the reduction of the Sn loss via a saccrifical Ge loss. This fact allows increasing the substrate temperature up to 350Âș C during the evaporation, forming a high quality kesterite material and therefore, reducing the deposition process to one single stage & 2015 Elsevier B.V. All rights reserved.RC acknowledges financial support from Spanish MINECO within
the RamĂłn y Cajal programme (RYC-2011-08521) and VIR for the
Juan de la Cierva fellowship (JCI-2011-10782). GB also acknowledges
the CSIC-JAE Pre-doctoral Program, co-funded by the European
Social Fund. This work was supported by the Marie Curie-IRSES
Project (PVICOKEST, GA: 269167), Marie Curie-ITN project (KESTCELL,
GA: 316488), DAAD project (INTERKEST, Ref: 57050358), and
MINECO projects (SUNBEAM, ENE2013-49136-C4-3-R) (TEC2012-
38901-C02-01). A. Scheu is acknowledged for GDOES measurements.Peer Reviewe
SHARDS: A global view of the star formation activity at z~0.84 and z~1.23
In this paper, we present a comprehensive analysis of star-forming galaxies
(SFGs) at intermediate redshifts (z~1). We combine the ultra-deep optical
spectro-photometric data from the Survey for High-z Absorption Red and Dead
Sources (SHARDS) with deep UV-to-FIR observations in the GOODS-N field.
Exploiting two of the 25 SHARDS medium-band filters, F687W17 and F823W17, we
select [OII] emission line galaxies at z~0.84 and z~1.23 and characterize their
physical properties. Their rest-frame equivalent widths
(EW([OII])), line fluxes, luminosities, star formation rates
(SFRs) and dust attenuation properties are investigated. The evolution of the
EW([OII]) closely follows the SFR density evolution of the
universe, with a trend of EW([OII])(1+z) up to
redshift z~1, followed by a possible flattening. The SF properties of the
galaxies selected on the basis of their [OII] emission are compared with
complementary samples of SFGs selected by their MIR and FIR emission, and also
with a general mass-selected sample of galaxies at the same redshifts. We
demonstrate observationally that the UVJ diagram (or, similarly, a cut in the
specific SFR) is only partially able to distinguish the quiescent galaxies from
the SFGs. The SFR-M relation is investigated for the different samples,
yelding a logarithmic slope ~1, in good agreement with previous results. The
dust attenuations derived from different SFR indicators (UV(1600), UV(2800),
[OII], IR) are compared and show clear trends with respect to both the stellar
mass and total SFR, with more massive and highly star-forming galaxies being
affected by stronger dust attenuation.Comment: Replaced to match the accepted version (24 pages, 1 table, 17
figures). Published in ApJ, 812, 155 (2015):
http://stacks.iop.org/0004-637X/812/15
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