1,011 research outputs found
Enfoque de intercambio social y la felicidad en el trabajo: explorando el efecto mediador del compromiso organizacional
This article aims to determine the direct and indirect effects of social exchange relationships Leader Member Exchange and Team Member Exchange (LMX and TMX) on organizational commitment and happiness at work. Based on the literature review and relying on the Social Exchange Theory perspective, the authors constructed the hypothetical structure, including the four variables under study. The sample comprised 177 employees from Mexican firms, and the proposed hypotheses were under examination through a path analysis. Results show that LMX, TMX, and happiness at work have a direct effect on organizational commitment. We also found an organizational commitment to be a partial relationship mediator between LMX and happiness at work.Este artículo tiene como objetivo determinar los efectos directos e indirectos de las relaciones de intercambio social, intercambio líder miembro e intercambio entre miembros del equipo (LMX y TMX) sobre el compromiso organizacional y la felicidad en el trabajo. Con base en la revisión de la literatura y apoyándose en la perspectiva de la Teoría del Intercambio Social, los autores construyeron la estructura hipotética, incluyendo las cuatro variables en estudio. La muestra estuvo compuesta por 177 empleados de empresas mexicanas, y las hipótesis propuestas fueron examinadas a través de un análisis de trayectoria. Los resultados muestran que LMX, TMX y la felicidad en el trabajo tienen un efecto directo sobre el compromiso organizacional. También encontramos que el compromiso organizacional media la relación parcial entre LMX y la felicidad en el trabajo
A search for evidence of irradiation in Centaurus X-4 during quiescence
We present a study of the neutron star X-Ray Transient Cen X-4. Our aim is to
look for any evidence of irradiation of the companion with a detailed analysis
of its radial velocity curve, relative contribution of the donor star and
Doppler tomography of the main emission lines. To improve our study all our
data are compared with a set of simulations that consider different physical
parameters of the system, like the disc aperture angle and the mass ratio. We
conclude that neither the radial velocity curve nor the orbital variation of
the relative donor's contribution to the total flux are affected by
irradiation. On the other hand, we do see emission from the donor star at
H and HeI 5876 which we tentatively attribute to irradiation effects.
In particular, the H emission from the companion is clearly
asymmetric and we suggest is produced by irradiation from the hot-spot.
Finally, from the velocity of the HeI 5876 spot we constrain the disc opening
angle to alpha=7-14 deg.Comment: 4 pages, 5 figures, accepted for publication in A&A as a R
Unexplored outflows in nearby low luminosity AGNs: the case of NGC 1052
Outflows play a central role in galaxy evolution shaping the properties of
galaxies. Understanding outflows and their effects in low luminosity AGNs, such
as LINERs, is essential (e.g. they are a numerous AGN population in the local
Universe). We obtained VLT/MUSE and GTC/MEGARA optical IFS-data for NGC1052,
the prototypical LINER. The stars are distributed in a dynamically hot disc,
with a centrally peaked velocity dispersion map and large observed velocity
amplitudes. The ionised gas, probed by the primary component is detected up to
30arcsec (3.3 kpc) mostly in the polar direction with blue and red
velocities (V250 km/s). The velocity dispersion map shows a
notable enhancement (90 km/s) crossing the galaxy along the major
axis of rotation in the central 10arcsec. The secondary component has a bipolar
morphology, velocity dispersion larger than 150 km/s and velocities up to 660
km/s. A third component is detected but not spatially resolved. The maps of the
NaD absorption indicate optically thick neutral gas with a velocity field
consistent with a slow rotating disc (V = 7712 km/s) but the
velocity dispersion map is off-centred without any counterpart in the flux map.
We found evidence of an ionised gas outflow with mass of 1.60.6
10 Msun, and mass rate of 0.40.2 Msun/yr. The outflow is propagating
in a cocoon of gas with enhanced turbulence and might be triggering the onset
of kpc-scale buoyant bubbles (polar emission). Taking into account the energy
and kinetic power of the outflow (1.30.9 10 erg and
8.83.5 10 erg/s, respectively) as well as its alignment
with both the jet and the cocoon, and that the gas is collisionally ionised, we
consider that the outflow is jet-powered, although some contribution from the
AGN is possible.Comment: A&A accepted 04/04/2022, 31 pages, 12 figures and 3 appendixe
La cova dels Galls Carboners (Mont-ral, Alt Camp), una cavitat d'inhumació col·lectiva durant l'edat del Bronze
Thematic Trends in Complementary and Alternative Medicine Applied in Cancer-Related Symptoms
Purpose: The main goal of this study is to discover the scientific evolution of Cancer-Related
Symptoms in Complementary and Alternative Medicine research area, analyzing the articles
indexed in the Web of Science database from 1980 to 2013.
Design/Methodology/Approach: A co-word science mapping analysis is performed under a
longitudinal framework (1980 to 2013). The documental corpus is divided into two subperiods,
1980–2008 and 2009–2013. Thus, the performance and impact rates, and conceptual evolution
of the research field are shown.
Findings: According to the results, the co-word analysis allows us to identify 12 main
thematic areas in this emerging research field: anxiety, survivors and palliative care,
meditation, treatment, symptoms and cancer types, postmenopause, cancer pain, low back
pain, herbal medicine, children, depression and insomnia, inflammation mediators, and
lymphedema. The different research lines are identified according to the main thematic areas,
centered fundamentally on anxiety and suffering prevention. The scientific community can
use this information to identify where the interest is focused and make decisions in different
ways.
Research limitation: Several limitations can be addressed: 1) some of the Complementary
and Alternative Medicine therapies may not have been included; 2) only the documents
indexed in Web of Science are analyzed; and 3) the thematic areas detected could change if
another dataset was considered.
Practical implications: The results obtained in the present study could be considered as an
evidence-based framework in which future studies could be built.
Originality/value: Currently, there are no studies that show the thematic evolution of this
research area
Stellar black holes at the dawn of the universe
It is well established that between 380000 and 1 billion years after the Big
Bang the Inter Galactic Medium (IGM) underwent a "phase transformation" from
cold and fully neutral to warm (~10^4 K) and ionized. Whether this phase
transformation was fully driven and completed by photoionization by young hot
stars is a question of topical interest in cosmology. AIMS. We propose here
that besides the ultraviolet radiation from massive stars, feedback from
accreting black holes in high-mass X-ray binaries (BH-HMXBs) was an additional,
important source of heating and reionization of the IGM in regions of low gas
density at large distances from star-forming galaxies. METHODS. We use current
theoretical models on the formation and evolution of primitive massive stars of
low metallicity, and the observations of compact stellar remnants in the near
and distant universe, to infer that a significant fraction of the first
generations of massive stars end up as BH-HMXBs. The total number of energetic
ionizing photons from an accreting stellar black hole in an HMXB is comparable
to the total number of ionizing photons of its progenitor star. However, the
X-ray photons emitted by the accreting black hole are capable of producing
several secondary ionizations and the ionizing power of the resulting black
hole could be greater than that of its progenitor. Feedback by the large
populations of BH-HMXBs heats the IGM to temperatures of ~10^4 K and maintains
it ionized on large distance scales. BH-HMXBs determine the early thermal
history of the universe and mantain it as ionized over large volumes of space
in regions of low density. This has a direct impact on the properties of the
faintest galaxies at high redshifts, the smallest dwarf galaxies in the local
universe, and on the existing and future surveys at radio wavelengths of atomic
hydrogen in the early universe.Comment: 7 pages, 2 figures, accepted to be published in Astronomy and
Astrophysic
Regorafenib Alteration of the BCL-xL/MCL-1 Ratio Provides a Therapeutic Opportunity for BH3-Mimetics in Hepatocellular Carcinoma Models
Background: The multikinase inhibitor regorafenib, approved as second-line treatment for hepatocellular carcinoma (HCC) after sorafenib failure, may induce mitochondrial damage. BH3-mimetics, inhibitors of specific BCL-2 proteins, are valuable drugs in cancer therapy to amplify mitochondrial-dependent cell death. Methods: In in vitro and in vivo HCC models, we tested regorafenib's effect on the BCL-2 network and the efficacy of BH3-mimetics on HCC treatment. Results: In hepatoma cell lines and Hep3B liver spheroids, regorafenib cytotoxicity was potentiated by BCL-xL siRNA transfection or pharmacological inhibition (A-1331852), while BCL-2 antagonism had no effect. Mitochondrial outer membrane permeabilization, cytochrome c release, and caspase-3 activation mediated A-1331852/regorafenib-induced cell death. In a patient-derived xenograft (PDX) HCC model, BCL-xL inhibition stimulated regorafenib activity, drastically decreasing tumor growth. Moreover, regorafenib-resistant HepG2 cells displayed increased BCL-xL and reduced MCL-1 expression, while A-1331852 reinstated regorafenib efficacy in vitro and in a xenograft mouse model. Interestingly, BCL-xL levels, associated with poor prognosis in liver and colorectal cancer, and the BCL-xL/MCL-1 ratio were detected as being increased in HCC patients. Conclusion: Regorafenib primes tumor cells to BH3-mimetic-induced cell death, allowing BCL-xL inhibition with A-1331852 or other strategies based on BCL-xL degradation to enhance regorafenib efficacy, offering a novel approach for HCC treatment, particularly for tumors with an elevated BCL-xL/MCL-1 ratio
Direct detection of neutralino dark matter in supergravity
The direct detection of neutralino dark matter is analysed in general
supergravity scenarios, where non-universal soft scalar and gaugino masses can
be present. In particular, the theoretical predictions for the
neutralino-nucleon cross section are studied and compared with the sensitivity
of dark matter detectors. We take into account the most recent astrophysical
and experimental constraints on the parameter space, including the current
limit on B(Bs-> mu+ mu-). The latter puts severe limitations on the dark matter
scattering cross section, ruling out most of the regions that would be within
the reach of present experiments. We show how this constraint can be softened
with the help of appropriate choices of non-universal parameters which increase
the Higgsino composition of the lightest neutralino and minimise the chargino
contribution to the b->s transition.Comment: 27 pages, 22 figure
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