7,512 research outputs found
Post-encoding stress does not enhance memory consolidation: The role of cortisol and testosterone reactivity
In contrast to the large body of research on the effects of stress-induced cortisol on memory consolidation in young people, far less attention has been devoted to understanding the effects of stress-induced testosterone on this memory phase. This study examined the psychobiological (i.e., anxiety, cortisol, and testosterone) response to the Maastricht Acute Stress Test and its impact on free recall and recognition for emotional and neutral material. Thirty-seven healthy young men and women were exposed to a stress (MAST) or control task post-encoding, and 24 h later, they had to recall the material previously learned. Results indicated that the MAST increased anxiety and cortisol levels, but it did not significantly change the testosterone levels. Post-encoding MAST did not affect memory consolidation for emotional and neutral pictures. Interestingly, however, cortisol reactivity was negatively related to free recall for negative low-arousal pictures, whereas testosterone reactivity was positively related to free recall for negative-high arousal and total pictures. This study provides preliminary evidence about a different reactivity of testosterone and cortisol to the MAST as well as on their effects on consolidation. Our results suggest a different pattern of relationships between these steroid hormones and the arousal of the negative images
Microanalysis Characterization of Bioactive Protein-Bound Polysaccharides Produced by Amanita Ponderosa Cultures
Different compounds of edible mushrooms are responsible for their bioactivity. The ability to
synthesize polysaccharides, namely protein–polysaccharide (PPS) complexes, is related to the antioxidant
capacity of these compounds and present great interest in preventing a number of diseases, including cancer,
cardiovascular and auto-immune diseases, and accelerated aging. Amanita ponderosa are wild edible mushrooms
that grow in Mediterranean “montado” areas [Portuguese name given to cork oak (Quercus suber) and holm oak
(Quercus ilex) forests]. The aim of this study was to evaluate the production of PPS complexes obtained from
A. ponderosa cultures using a new microanalytical approach to quickly and easily monitor the production process.
Microanalysis using Fourier-transform infrared using attenuated total reflection and Raman spectroscopy of PPS
samples showed spectra compatible with identification of this type of compound in culture extracts. PPS separated
by size-exclusion chromatography showed seven main complexes. Molecular weights of the main PPS complexes
isolated from cultures ranged between 1.5 and 20 kDa and did not present toxicity against Artemia salina,
demonstrating the potential of A. ponderosa as a source of biologically active compounds with nutraceutical value.
Application of this microanalytical approach to monitoring the production of PPS compounds can be successfully
applied in biotechnological processes
Effects of sex and menstrual cycle phase on cardiac response and alpha- amylase levels in psychosocial stress
The impact of sex and the menstrual cycle phase on the autonomic response to psychosocial stress remains controversial. This study explored autonomic nervous system activity through salivary alpha-amylase, heart rate, and heart rate variability responses to the Trier Social Stress Test (TSST) in healthy young people. The sample was composed of 25 men, 26 women in the luteal phase, and 25 women in the follicular phase, from 18 to 25 years of age. Participants were exposed to the TSST or a control condition. The results indicate that women in their follicular phase showed a blunted alpha-amylase response to stress compared to men and women in the luteal phase. In addition, men showed higher sympatho-vagal activity in the stress condition compared to the two groups of women. These results confirm that sex and the menstrual cycle phase are potential modulators of autonomic nervous system reactivity to psychosocial stress
The nature of dark matter and the density profile and central behavior of relaxed halos
We show that the two basic assumptions of the model recently proposed by
Manrique and coworkers for the universal density profile of cold dark matter
(CDM) halos, namely that these objects grow inside out in periods of smooth
accretion and that their mass profile and its radial derivatives are all
continuous functions, are both well understood in terms of the very nature of
CDM. Those two assumptions allow one to derive the typical density profile of
halos of a given mass from the accretion rate characteristic of the particular
cosmology. This profile was shown by Manrique and coworkers to recover the
results of numerical simulations. In the present paper, we investigate its
behavior beyond the ranges covered by present-day N-body simulations. We find
that the central asymptotic logarithmic slope depends crucially on the shape of
the power spectrum of density perturbations: it is equal to a constant negative
value for power-law spectra and has central cores for the standard CDM power
spectrum. The predicted density profile in the CDM case is well fitted by the
3D S\'ersic profile over at least 10 decades in halo mass. The values of the
S\'ersic parameters depend on the mass of the structure considered. A practical
procedure is provided that allows one to infer the typical values of the best
NFW or S\'ersic fitting law parameters for halos of any mass and redshift in
any given standard CDM cosmology.Comment: 9 pages, 6 figures, to appear in the ApJ vol. 647, september 20,
2007. Minor changes to match the published versio
El rol del control personal en la función paliativa de la justificación del sistema entre la población indígena y no indígena de estudiantes peruanos
Indexación: Scopus.In this article we propose a mediation model for the association between system justification and psychological well-being (i.e., the palliative function of ideology), based on system justification theory and compensatory control theory. Specifically, we argue that endorsing system-justifying beliefs leads to increased perceived personal control, which in turn predicts higher well-being. We used a convenience sample of students from two Peruvian universities. The results showed that system justification was related to general psychological well-being and personal control. In addition, indigenous students rated lower on system justification, general psychological well-being, self-esteem and personal control. Next, we found that the association between system justification and general psychological well-being was stronger among indigenous students, and this relationship was partially mediated by personal control. In addition, we showed that the mediation model is moderated by ethnicity, so that personal control is a mediator only among non-indigenous participants. We conclude that personal control is a mechanism involved in the palliative function of ideology among this group. Finally, we discuss possible explanations for the mechanisms involved in the palliative function of ideology among low-status individuals. © 2018, © 2018 Fundacion Infancia y Aprendizaje.En este artículo se propone un modelo de mediación de las
relaciones entre la justificación del sistema y el bienestar psicológico (i.e.,
la función paliativa de la ideología) basado en las teorías de la justificación
del sistema y del control compensatorio. En concreto, se propone que la
adopción de creencias justificativas del sistema produce un aumento del
control personal percibido que, a su vez, predice niveles más elevados de bienestar. En este estudio se utilizó una muestra por conveniencia de estudiantes
provenientes de dos universidades peruanas. Los resultados muestran
que la justificación del sistema está relacionada con el bienestar psicológico
general y con el control personal. Además, los estudiantes indígenas mostraron
niveles más reducidos de justificación del sistema, bienestar
psicológico general, autoestima y control personal. También se observó que
la relación entre la justificación del sistema y el bienestar psicológico general
era más fuerte entre los estudiantes indígenas y que el control personal
mediaba parcialmente en esta relación. Asimismo, mostramos que la etnicidad
es un factor moderador del modelo de mediación, por lo que el control
personal es un mediador únicamente entre los participantes no indígenas. El
estudio concluye que el control personal es un mecanismo que interviene en
la función paliativa de la ideología en este grupo. Por último, se discuten
posibles explicaciones de los mecanismos implicados en la función paliativa
de la ideología entre individuos de estatus social bajo.https://www.tandfonline.com/doi/full/10.1080/02134748.2018.153765
Drought effects on specific-cause mortality in Lisbon from 1983 to 2016: risks assessment by gender and age groups
Portugal (Southwestern Europe) experiences a high incidence of dry hazards such as drought, a phenomenon that entails a notable burden of morbidity and mortality worldwide. For the first time in the Lisbon district, a time-series study was conducted to evaluate the impact of drought measured by the Standardised Precipitation Index (SPI) and Standardised Precipitation-Evapotranspiration Index (SPEI) on the daily natural, circulatory, and respiratory mortality from 1983 to 2016. An assessment by gender and adult age population groups (45-64, 65-74, ≥75 years old) was included. To estimate the relative risks and attributable risks, generalised linear models with a Poisson link were used. Additionally, the influence of heatwaves and atmospheric pollution for the period from 2007 to 2016 (available period for pollution data) was considered. The main findings indicate statistically significant associations between drought conditions and all analysed causes of mortality. Moreover, SPEI shows an improved capability to reflect the different risks. People in the 45-64 year-old group did not indicate any significant influence in any of the cases, whereas the oldest groups had the highest risk. The drought effects on mortality among the population varied across the different study periods, and in general, the men population was affected more than the women population (except for the SPEI and circulatory mortality during the long study period). The short-term influence of droughts on mortality could be explained primarily by the effect of heatwaves and pollution; however, when both gender and age were considered in the Poisson models, the effect of drought also remained statistically significant when all climatic phenomena were included for specific groups of the total population and men. This type of study facilitates a better understanding of the population at risk and allows the development of more effective measures to mitigate the drought effects on the population.publishe
Molecular evaluation of some Amanita ponderosa and fungal strains living in association with these mushrooms in the south western Iberian Peninsula
Amanita ponderosa are wild edible mushrooms that
grow only in some microclimates, particularly those in the southwestern
part of the Iberian Peninsula. Due to the vast diversity of
mushrooms in nature, as well as nutrient variability, which is
highly dependent on soil type and environmental conditions, it is
essential to be able to characterize fungal microbiota that lives in
association with mushrooms and to differentiate A. ponderosa
strains of different regions for certification purposes. In this study,
we characterized the genetic profile of A. ponderosa mushrooms
and the fungal strains that live in association with them in their
natural habitat and compared the fingerprinting profiles obtained
by M13-PCR amplification of the genomic DNA.We found that
the predominant fungal isolates living in association with A.
ponderosa were Aspergillus spp., Penicillium spp. and Mucor
spp. M13-PCR molecular analysis showed that different fungal
isolates had different genetic profiles. This approach allowed us
to differentiate the different fungi strains isolated from fruiting
bodies of A. ponderosa both rapidly and in a reproducible
manner and to group them according to genus. Our fingerprinting
analyses also distinguished different A. ponderosa mushrooms
collected from different regions. Consequently, we conclude that this method is a very discriminatory approach for differentiating
both A. ponderosa from different sites and the fungal microbiota
that lives in association with these mushrooms
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