745 research outputs found
Sephardiellinae, a new Middle Triassic conodont subfamily
Sephardiellinae (nov. subfam.) encompasses a Middle Triassic Gondolleloid lineage that originated in the Sephardic realm, westernmost shallow Neotethys, from where, in the course of the Ladinian and earliest Carnian, some of its species spread to the world oceans, before extinction as a result of the Carnian salinity crisis. It is composed of two genera, Sephardiella and Pseudofurnishius. Differential criteria in its septimembrate apparatus are the basal cavity structure of P1 element and morphological variations in the P2 and S3 elements.La nueva subfamilia Sephardiellinae está comprendida dentro del linaje de Gondolellidae del Triásico Medio y se originó en el Dominio SefardÃ, la parte más occidental del Neotetis. Durante el Ladiniense-Carniense Inferior, algunas de sus especies irradian y se distribuyen por todos los océanos. Su extinción está relacionada con la crisis de salinidad que tuvo lugar en el Carniense. La nueva subfamilia está constituida por dos géneros, Sephardiella y Pseudofurnishius las diferencias morfológicas de su aparato septimembrado, como son la estructura de la cavidad basal del elemento P1 y las variaciones morfológicas de los elementos P2 y S3, constituyen el criterio utilizado
Magnetic long-range order induced by quantum relaxation in single-molecule magnets
Can magnetic interactions between single-molecule magnets (SMMs) in a crystal
establish long-range magnetic order at low temperatures deep in the quantum
regime, where the only electron spin-fluctuations are due to incoherent
magnetic quantum tunneling (MQT)? Put inversely: can MQT provide the
temperature dependent fluctuations needed to destroy the ordered state above
some finite Tc, although it should basically itself be a T-independent process?
Our experiments on two novel Mn4 SMMs provide a positive answer to the above,
showing at the same time that MQT in the SMMs has to involve spin-lattice
coupling at a relaxation rate equaling that predicted and observed recently for
nuclear spin-mediated quantum relaxation.Comment: 4 pages, 3 figure
Thermal Soak Analysis of Earth Entry Vehicles
The Multi-Mission Earth Entry Vehicle project is developing an integrated tool called Multi Mission System Analysis for Planetary Entry Descent and Landing that will provide key technology solutions including mass sizing, aerodynamics, aerothermodynamics, and thermal and structural analysis for any given sample return mission. Thermal soak analysis and temperature predictions of various components including the payload container of the entry vehicle are part of the solution that this tool will offer to mission designers. The present paper focuses on the thermal soak analysis of an entry vehicle design based on the Mars Sample Return entry vehicle geometry and discusses a technical approach to develop parametric models for thermal soak analysis that will be integrated into the tool
The ROCK inhibitor Fasudil prevents chronic restraint stress-induced depressive-like behaviors and dendritic spine loss in rat hippocampus
Indexación: Web of Science; Scopus.Background: Dendritic arbor simplification and dendritic spine loss in the hippocampus, a limbic structure implicated in mood disorders, are assumed to contribute to symptoms of depression. These morphological changes imply modifications in dendritic cytoskeleton. Rho GTPases are regulators of actin dynamics through their effector Rho kinase. We have reported that chronic stress promotes depressive-like behaviors in rats along with dendritic spine loss in apical dendrites of hippocampal pyramidal neurons, changes associated with Rho kinase activation. The present study proposes that the Rho kinase inhibitor Fasudil may prevent the stress-induced behavior and dendritic spine loss. Methods: Adult male Sprague-Dawley rats were injected with saline or Fasudil (i.p., 10 mg/kg) starting 4 days prior to and maintained during the restraint stress procedure (2.5 h/d for 14 days). Nonstressed control animals were injected with saline or Fasudil for 18 days. At 24 hours after treatment, forced swimming test, Golgi-staining, and immuno-western blot were performed. Results: Fasudil prevented stress-induced immobility observed in the forced swimming test. On the other hand, Fasudiltreated control animals showed behavioral patterns similar to those of saline-treated controls. Furthermore, we observed that stress induced an increase in the phosphorylation of MYPT1 in the hippocampus, an exclusive target of Rho kinase. This change was accompanied by dendritic spine loss of apical dendrites of pyramidal hippocampal neurons. Interestingly, increased pMYPT1 levels and spine loss were both prevented by Fasudil administration. Conclusion: Our findings suggest that Fasudil may prevent the development of abnormal behavior and spine loss induced by chronic stress by blocking Rho kinase activity.https://academic.oup.com/ijnp/article/20/4/336/263217
Depression symptoms and mortality in elderly peruvian navy veterans: a retrospective cohort study
Abstract: Our study was design to determine the association between depressive symptoms and mortality in adults over 60 years old Navy Peruvian Veterans. We performed a retrospective cohort study based on a previous cohort study. A total of 1681 patients over 60 years old were included between 2010–2015. Demographic information, self-reported information about falls, physical frailty assessment, tobacco consumption, hypertension, Type 2 Diabetes Mellitus, Chronic Obstructive Pulmonary Disease and was collected. Depression was assessed by the short form of the Geriatric Depression Scale. We found that depressive symptoms were present in 24.9% of the participants and 40.5% of them died. Mortality risk in patients with depressive symptoms, physical frailty, and male sex was: RR of 23.1 (95% CI: 11.7–45.7), 3.84 (95% CI: 2.16–6.82), and 1.37 (95% CI: 1.07–1.75) respectively. We concluded that depressive symptoms in Peruvian retired military personnel and their immediate relatives are high and are significatively associated with mortality. Also, being male and frail was associated with an increased risk of death. This reinforces that early detection and assessment of depressive symptoms could be an opportunity to improve the health status of older adults
USE OF MORINGA SEED (Moringa oleifera Lam.) AS A BIOCOAGULANT TO IMPROVE SURFACE WATER QUALITY
Using Moringa oleifera (Moringa oleifera Lam.) seed as a biocoagulant to enhance surface water's physical and chemical quality was the goal of this study. The methodology applied for the generation of experimental data was through the use of the Jar Test equipment, in a dose of 40 mg/L to 140 mg/L, then a fast mixing of 100 rpm for 1 minute and a slow mixing of 40 rpm for 10 minutes was performed, and sedimentation was left for 5 to 30 minutes, with 5 minutes intervals between each dose. The results show that an optimal biocoagulant dose of 100 mg/L at 20 minutes produced a turbidity reduction effectiveness of 97.06%. Hardness fell by 12% of its starting value, conductivity and total dissolved solids increased dramatically, and there was a 92.3% reduction in perceived colour, which showed that the use of Moringa seeds as a coagulant had a favourable effect on reducing the concentration of turbidity and colour. Because of this, Moringa (Moringa oleifera Lam.) can be used as a natural source to purify drinking water. The Tukey HSD test applied to the turbidity removal percentages, indicates that the means are not significantly different. However, the experimental evaluation indicates that after 20 minutes, the best results are obtained
Testing Gaussianity on Archeops Data
A Gaussianity analysis using a goodness-of-fit test and the Minkowski
functionals on the sphere has been performed to study the measured Archeops
Cosmic Microwave Background (CMB) temperature anisotropy data for a 143 GHz
Archeops bolometer. We consider large angular scales, greater than 1.8 degrees,
and a large fraction of the North Galactic hemisphere, around 16%, with a
galactic latitude b > 15 degrees.
The considered goodness-of-fit test, first proposed by Rayner & Best (1989),
has been applied to the data after a signal-to-noise decomposition. The three
Minkowski functionals on the sphere have been used to construct a chi-square
statistic using different thresholds. The first method has been calibrated
using simulations of Archeops data containing the CMB signal and instrumental
noise in order to check its asymptotic convergence. Two kind of maps produced
with two different map-making techniques (coaddition and Mirage) have been
analysed.
Archeops maps for both Mirage and coaddition map-making, have been found to
be compatible with Gaussianity. From these results we can exclude a dust and
atmospheric contamination larger than 7.8% (90% CL). Also the non-linear
coupling parameter f_{nl} can be constrained to be -800 < f_{nl} < 1100 at the
95% CL and on angular scales of 1.8 degrees. For comparison, the same method
has been applied to data from the NASA WMAP satellite in the same region of
sky. The 1-year and 3-year releases have been used. Results are compatible with
those obtained with Archeops, implying in particular an upper limit for f_{nl}
on degree angular scales.Comment: A&A accepted. The limits on the contamination and the fnl parameter
have been improve
Measurement of total and differential cross sections of neutrino and antineutrino coherent pi(+/-) production on carbon
Neutrino induced coherent charged pion production on nuclei, (nu) over bar (mu)A -\u3e mu(+/-)pi(-/+) A, is a rare inelastic interaction in which the four-momentum squared transferred to the nucleus is nearly zero, leaving it intact. We identify such events in the scintillator of MINERvA by reconstructing vertical bar t vertical bar from the final state pion and muon momenta and by removing events with evidence of energetic nuclear recoil or production of other final state particles. We measure the total neutrino and antineutrino cross sections as a function of neutrino energy between 2 and 20 GeV and measure flux integrated differential cross sections as a function of Q(2), E-pi, and theta(pi). The Q(2) dependence and equality of the neutrino and antineutrino cross sections at finite Q(2) provide a confirmation of Adler\u27s partial conservation of axial current hypothesis
Aspects of the FM Kondo Model: From Unbiased MC Simulations to Back-of-an-Envelope Explanations
Effective models are derived from the ferromagnetic Kondo lattice model with
classical corespins, which greatly reduce the numerical effort. Results for
these models are presented. They indicate that double exchange gives the
correct order of magnitude and the correct doping dependence of the Curie
temperature. Furthermore, we find that the jump in the particle density
previously interpreted as phase separation is rather explained by ferromagnetic
polarons.Comment: Proceedings of Wandlitz Days of Magnetism 200
An Origin of CMR: Competing Phases and Disorder-Induced Insulator-to-Metal Transition in Manganites
We theoretically explore the mechanism of the colossal magnetoresistance in
manganese oxides by explicitly taking into account the phase competition
between the double-exchange ferromagnetism and the charge-ordered insulator. We
find that quenched disorder causes a drastic change of the multicritical phase
diagram by destroying the charge-ordered state selectively. As a result, there
appears a nontrivial phenomenon of the disorder-induced insulator-to-metal
transition in the multicritical regime. On the contrary, the disorder induces a
highly-insulating state above the transition temperature where charge-ordering
fluctuations are much enhanced. The contrasting effects provide an
understanding of the mechanism of the colossal magnetoresistance. The obtained
scenario is discussed in comparison with other theoretical proposals such as
the polaron theory, the Anderson localization, the multicritical-fluctuation
scenario, and the percolation scenario.Comment: 16 pages, 7 figures, submitted to Wandlitz Days on Magnetism:
Local-Moment Ferromagnets: Unique Properties for Modern Application
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