5,231 research outputs found
Phenomenology of The Left-Right Twin Higgs Model
The twin Higgs mechanism has recently been proposed to solve the little
hierarchy problem. We study the implementation of the twin Higgs mechanism in
left-right models. At TeV scale, heavy quark and gauge bosons appear, with rich
collider phenomenology. In addition, there are extra Higgses, some of which
couple to both the Standard Model fermion sector and the gauge sector, while
others couple to the gauge bosons only. We present the particle spectrum, and
study the general features of the collider phenomenology of this class of model
at the Large Hadron Collider.Comment: 41 pages, version appears in PR
The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry
GJ3470b is a rare example of a "hot Uranus" transiting exoplanet orbiting a
nearby M1.5 dwarf. It is of crucial interest for atmospheric studies because it
is one of the most inflated low-mass planets known, bridging the boundary
between "super-Earths" and Neptunian planets. We present two new ground-based
light curves of GJ3470b gathered by the LBC camera at the Large Binocular
Telescope. Simultaneous photometry in the ultraviolet (lambda_c = 357.5 nm) and
optical infrared (lambda_c = 963.5 nm) allowed us to detect a significant
change of the effective radius of GJ3470b as a function of wavelength. This can
be interpreted as a signature of scattering processes occurring in the
planetary atmosphere, which should be cloud-free and with a low mean molecular
weight. The unprecedented accuracy of our measurements demonstrates that the
photometric detection of Earth-sized planets around M dwarfs is achievable
using 8-10m size ground-based telescopes. We provide updated planetary
parameters, and a greatly improved orbital ephemeris for any forthcoming study
of this planet.Comment: 8 pages, 6 figures, 1 table; accepted for publication in A&
Hyperosmotic priming of arabidopsis seedlings establishes a long-term somatic memory accompanied by specific changes of the epigenome
<p>Background: In arid and semi-arid environments, drought and soil salinity usually occur at the beginning and end of a plant's life cycle, offering a natural opportunity for the priming of young plants to enhance stress tolerance in mature plants. Chromatin marks, such as histone modifications, provide a potential molecular mechanism for priming plants to environmental stresses, but whether transient exposure of seedlings to hyperosmotic stress leads to chromatin changes that are maintained throughout vegetative growth remains unclear.</p>
<p>Results: We have established an effective protocol for hyperosmotic priming in the model plant Arabidopsis, which includes a transient mild salt treatment of seedlings followed by an extensive period of growth in control conditions. Primed plants are identical to non-primed plants in growth and development, yet they display reduced salt uptake and enhanced drought tolerance after a second stress exposure. ChIP-seq analysis of four histone modifications revealed that the priming treatment altered the epigenomic landscape; the changes were small but they were specific for the treated tissue, varied in number and direction depending on the modification, and preferentially targeted transcription factors. Notably, priming leads to shortening and fractionation of H3K27me3 islands. This effect fades over time, but is still apparent after a ten day growth period in control conditions. Several genes with priming-induced differences in H3K27me3 showed altered transcriptional responsiveness to the second stress treatment.</p>
<p>Conclusion: Experience of transient hyperosmotic stress by young plants is stored in a long-term somatic memory comprising differences of chromatin status, transcriptional responsiveness and whole plant physiology.</p>
Spectral decomposition of starbursts and AGNs in 5-8 micron Spitzer IRS spectra of local ULIRGs
We present an analysis of the 5-8 micron Spitzer-IRS spectra of a sample of
68 local Ultraluminous Infrared Galaxies (ULIRGs). Our diagnostic technique
allows a clear separation of the active galactic nucleus (AGN) and starburst
(SB) components in the observed mid-IR emission, and a simple analytic model
provides a quantitative estimate of the AGN/starburst contribution to the
bolometric luminosity. We show that AGNs are ~30 times brighter at 6 micron
than starbursts with the same bolometric luminosity, so that even faint AGNs
can be detected. Star formation events are confirmed as the dominant power
source for extreme infrared activity, since ~85% of ULIRG luminosity arises
from the SB component. Nonetheless an AGN is present in the majority (46/68) of
our sources.Comment: 5 Pages, 3 figures. MNRAS Letters, Accepte
The economic crisis and changes in work-family arrangements in six European countries
Over the past decades, there has been a substantial increase in female labour force participation, and the
number of dual-earner and female-earner households has risen throughout western countries. However,
the recent economic crisis has caused large losses in employment for both women and men, potentially
yielding unexpected consequences for the evolution of work\u2013family arrangements. This article carries
out a comparative analysis of the relationship between the 2008/2009 economic crisis and work\u2013family
arrangements in Europe. Using data for six countries from the European Union Statistics on Income and
Living Conditions, this article fills a gap in the literature by addressing three issues: (1) whether work\u2013family
arrangements have changed from before to after the beginning of the economic downturn in countries with
different gender and welfare regimes (Germany, Greece, Spain, France, Sweden and the United Kingdom),
(2) whether changes in work\u2013family arrangements have occurred at different levels of the social strata and
(3) whether couples have moved from dual-earner to male- or female-breadwinner. The results indicate
changes in work\u2013family arrangements in those countries worst hit by the economic crisis, Greece and
Spain, where dual-earner and male-breadwinner households have decreased and no-earner and femalemain-
earner households have increased. Moreover, the results show that in these two countries, all social
strata \u2013 proxied through women\u2019s level of education \u2013 have been affected by the crisis. In contrast, only
moderate changes in work\u2013family arrangements among all women can be observed in countries less hit
by the economic downturn. The findings for the two southern European countries are troubling, as the
increases in no-earner and female-breadwinner households point to worsening economic conditions
throughout the population and to a halt in the process that for several decades had been leading to more
equality in the distribution of employment between gender
Screening of some algal species for adsorption of iron, copper and mercury from untreated textile effluent in Kano, Nigeria
The research was carried out to screen endogenous species of algae for the adsorption of heavy metals from untreated effluents of Africa Textile Manufacturer (ATM) in Kano between July 2014- June, 2015. Primary field investigation and laboratory analysis were the main sources of data in the study. The study areas were divided into three strata within which samples were collected using stratified sampling techniques from a depth of 0-30cm. The study assessed the adsorption capacity of heavy metals namely: Iron (Fe), Copper (Cu) and Mercury (Hg) by some algal species using Atomic Absorbance Spectrophotometer (AAS). Indigenous algal species identified and isolated were Anabaena planctonica, Microcystis aeruginosa and Spirulina major using microscopy and standard phycological chart as described by Komerak and Anagnostidis, (1989). Bioremediation Bioassay was conducted to assess the adsorption capacity of the isolated organisms. The results showed that, tested organisms reduced the concentration level of heavy metals in the effluents to the standard limit proposed by FEPA (1997), WHO (1999) and (ICLARM, 1997). Spirulina major was found to sequester more Cu (22.80%) followed by Microcystis aeruginosa (21.34%). Higher concentration of Fe (5.77%) and Hg (5.15%) were removed by Microcystis aeruginosa. These findings indicated that all the tested organisms possessed great potential in removing heavy metals from untreated textile effluents. These findings also showed that adsorption of heavy metals by the tested organisms increased with time from 3-9 weeks of inoculation and adsorption was significantly higher at 9 weeks after inoculation.Keywords: Algal Species, ATM, Effluent and Heavy metal
Maternal employment : enabling factors in context
Maternal employment is still below the overall EU recommended level of 60% in many European
countries. Understanding the individual, household and contextual circumstances under which
mothers of children of different ages are likely to be employed is crucial to develop strategies
capable of increasing maternal employment. This article takes a comparative approach to
investigating the characteristics associated with maternal employment in the presence of children
aged 0\u20132, 3\u20135, 6\u20139 and 10\u201312 years. We model the probability of being employed full-time, parttime
or being a homemaker using EU-SILC data (2004 to 2007) from Germany, Italy, Norway
and the United Kingdom \u2013 four countries belonging to different gender and welfare regimes. The
results indicate that individual and household characteristics are more relevant in determining
mothers\u2019 employment in countries where the state is less supportive towards maternal
employment: Italy and to a lesser extent Germany and the UK \u2013 for the period observed
The Relationship Between the Civic Engagement of Parents and Children : a Cross-National Analysis of 18 European Countries
Although previous research has suggested the existence of a positive association
between the political activities of parents and children, little is known about
other forms of civic engagement. In particular, the literature lacks an international
comparative study on the intergenerational transmission of civic involvement. Using
Bayesian multilevel models on data from the European Union Statistics on Income
and Living Conditions (EU-SILC) 2006 special module on social participation, this
article tests hypotheses on the patterns of civic engagement of parents and children
in 18 European countries with different political legacies. Our results show a positive
association between the participation in associational activities of parents and
children in all the considered countries, above and beyond individual and contextual
characteristics. In particular, we do not find an evident East\u2013West gap in the
socialization process, suggesting that the Communist past of Eastern and Central
European countries has little influence on what can be considered a basic mechanism
of civic learning
The Best Is Yet to Come? Attitudes towards gender roles among adolescents in 36 countries
In the present article, we look at attitudes toward
gender roles among young women and men in 36 countries
with different levels of societal gender inequality. By applying
multilevel models to data from the International Civic and
Citizenship Education Study 2009, the study contributes to
our understanding of gender inequality by showing that (a)
both young women and young men (in 8th grade;
Mage = 14.39 years) display more gender-egalitarian attitudes
in countries with higher levels of societal gender equality; (b)
young women in all countries have more egalitarian attitudes
toward gender roles than young men do, but (c) the gender gap
in attitudes is more evident in more egalitarian contexts; and
(d) a higher level of maternal education is associated with
more gender-egalitarian attitudes among young women. In
contrast, no statistically significant association emerges between
maternal employment and young men\u2019s attitudes.
Overall, the findings suggest that adolescents in different contexts
are influenced by the dominant societal discourse on
gender inequality, which they interiorize and display through
their own attitudes toward gender roles. However, the findings
also indicate that young women are more responsive to external
cues than young men are. This result, coupled with the fact
that young men in egalitarian contexts have not adopted
gender-egalitarian attitudes to the same extent as young women,
is concerning because it suggests a slowdown in the
achievement of societal gender equality that is still far from
being reache
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