172 research outputs found
Ammonia and other parent molecules in comet 10P/Tempel 2 from Herschel/HIFI and ground-based radio observations
The Jupiter-family comet 10P/Tempel 2 was observed during its 2010 return
with the Herschel Space Observatory. We present here the observation of the (J,
K) = (1, 0)-(0, 0) transition of ammonia at 572 GHz in this comet with the
Heterodyne Instrument for the Far Infrared (HIFI) of Herschel. We also report
on radio observations of other molecules (HCN, CH3OH, H2S and CS) obtained
during the 1999 return of the comet with the CSO telescope and the JCMT, and
during its 2010 return with the IRAM 30-m telescope. Molecular abundances
relative to water are 0.09%, 1.8%, 0.4%, and 0.08% for HCN, CH3OH, H2S, and CS,
respectively. An abundance of 0.5% for NH3 is obtained, which is similar to the
values measured in other comets. The hyperfine structure of the ammonia line is
resolved for the first time in an astronomical source. Strong anisotropy in the
outgassing is present in all observations from 1999 to 2010 and is modelled to
derive the production rates.Comment: 6 pages and 8 figures. Accepted for publication in Astronomy &
Astrophysic
Exploring the feasibility of using Participatory Action Research (PAR) as a mechanism for school culture change to improve mental health
Adolescence is a key time to prevent or reduce poor mental health outcomes. Supportive school environments play an important role in this, and the concept of health-promoting schools have been supported globally. Participatory action research (PAR) combines theory, practice, action, and reflection by developing practical solutions to address concerns and issues within communities. Running four PAR groups across three secondary schools, we explored the feasibility of using the approach as a mechanism for bringing about culture change and improving mental health. We undertook interviews and focus groups with students (n = 24), school staff (n = 11), facilitators (n = 3), and parents/carers (n = 2). Findings are organised under five key headings: 1) Establishing PAR groups, and the PAR cycle; 2) PAR group impact; 3) Facilitators of PAR success; 4) Barriers to PAR success; 5) Future recommendations. This study demonstrated the feasibility of PAR as a tool to improve school culture. Students participating in PAR were engaged, passionate, and motivated to influence and transform school culture to improve mental health. Future research should aim to trial the PAR approach on a larger scale, to determine whether the barriers and facilitators of PAR success identified here are relevant and transferable to schools in other contexts, and to measure the impact of such initiatives on mental health outcomes
Domestic violence and self-poisoning in Sri Lanka
Background. There is increasing evidence that domestic violence (DV) is an important risk factor for suicidal behaviour. The level of risk and its contribution to the overall burden of suicidal behaviour among men and women has not been quantified in South Asia. We carried out a large case-control study to examine the association between DV and self-poisoning in Sri Lanka. Methods. Cases (N = 291) were patients aged ⩾18 years, admitted to a tertiary hospital in Kandy Sri Lanka for self-poisoning. Sex and age frequency matched controls were recruited from the hospital’s outpatient department (N = 490) and local population (N = 450). Exposure to DV was collected through the Humiliation, Afraid, Rape, Kick questionnaire. Multivariable logistic regression models were conducted to estimate the association between DV and self-poisoning, and population attributable fractions were calculated. Results. Exposure to at least one type of DV within the previous 12 months was strongly associated with self-poisoning for women [adjusted OR (AOR) 4.08, 95% CI 1.60–4.78] and men (AOR 2.52, 95% CI 1.51–4.21), compared to those reporting no abuse. Among women, the association was strongest for physical violence (AOR 14.07, 95% CI 5.87–33.72), whereas among men, emotional abuse showed the highest risk (AOR 2.75, 95% CI 1.57–4.82). PAF % for exposure to at least one type of DV was 38% (95% CI 32–43) in women and 22% (95% CI 14–29) in men. Conclusions. Multi-sectoral interventions to address DV including enhanced identification in health care settings, community-based strategies, and integration of DV support and psychological services may substantially reduce suicidal behaviour in Sri Lanka
Searches for HCl and HF in comets 103P/Hartley 2 and C/2009 P1 (Garradd) with the Herschel space observatory
HCl and HF are expected to be the main reservoirs of fluorine and chlorine
wherever hydrogen is predominantly molecular. They are found to be strongly
depleted in dense molecular clouds, suggesting freeze-out onto grains in such
cold environments. We can then expect that HCl and HF were also the major
carriers of Cl and F in the gas and icy phases of the outer solar nebula, and
were incorporated into comets. We aimed to measure the HCl and HF abundances in
cometary ices as they can provide insights on the halogen chemistry in the
early solar nebula. We searched for the J(1-0) lines of HCl and HF at 626 and
1232 GHz, respectively, using the HIFI instrument on board the Herschel Space
Observatory. HCl was searched for in comets 103P/Hartley 2 and C/2009 P1
(Garradd), whereas observations of HF were conducted in comet C/2009 P1. In
addition, observations of HO and HO lines were performed in C/2009
P1 to measure the HO production rate. Three lines of CHOH were
serendipitously observed in the HCl receiver setting. HCl is not detected,
whereas a marginal (3.6-) detection of HF is obtained. The upper limits
for the HCl abundance relative to water are 0.011% and 0.022%, for 103P and
C/2009 P1, respectively, showing that HCl is depleted with respect to the solar
Cl/O abundance by a factor more than 6 in 103P, where the error is
related to the uncertainty in the chlorine solar abundance. The marginal HF
detection obtained in C/2009 P1 corresponds to an HF abundance relative to
water of (1.80.5) 10, which is approximately consistent
with a solar photospheric F/O abundance. The observed depletion of HCl suggests
that HCl was not the main reservoir of chlorine in the regions of the solar
nebula where these comets formed. HF was possibly the main fluorine compound in
the gas phase of the outer solar nebula.Comment: Accepted for publication in Astronomy & Astrophysic
Multiband Comparative Study of Optical Microvariability in RL vs. RQ Quasars
We present the results of an optical multi-band (BVR) photometric monitoring
program of 22 core-dominated radio-loud quasars (CRLQs) and 22 radio-quiet
quasars (RQQs). The aim was to compare the properties of microvariability in
both types of quasars. We detected optical microvariability in 5 RQQs and 4
CRLQs. Our results confirm that microvariability in RQQs may be as frequent as
in CRLQs. In addition we compare microvariability duty cycles in different
bands. Finally, the implications for the origin of the microvariations are
briefly discussed.Comment: 17 pages, 14 figures, Accepted for publication in the Astronomical
Journa
What is the impact of structural and cultural factors and interventions within educational settings on promoting positive mental health and preventing poor mental health: a systematic review
Mental health (MH) difficulties are on the increase among children and young people (CYP). Evidence has shown that educational settings contain both risk and protective factors for MH. This review investigated which structural and cultural factors and interventions within educational settings promote positive MH and prevent poor MH in 4-18 year olds. Searches were conducted in PsychINFO, Embase, ERIC, ASSIA and British Education Index, and reference lists from key studies and relevant systematic reviews were hand-searched. Intervention, cohort, and qualitative studies were included. Of the 62 included papers, 36 examined cultural factors (30 social/relational and six value-related) while 12 studies examined structural factors (eight organisational and four physical) and 14 studies examined multiple factors. There was strong evidence for the impact of positive classroom management techniques, access to physical activity, and peer mentoring on student MH. Studies examining the impact of positive school culture, teacher training in MH and parent involvement in school MH activities also found predominantly positive results for student MH, albeit the evidence was of lower quality or from a low number of studies. Few studies explicitly examined the impact of interventions on MH inequalities; those that did indicated limited if any reduction to inequalities. A very small number of studies suggested that interventions targeting those at risk of poor MH due to socioeconomic factors could successfully improve wellbeing and reduce depression, anxiety and behavioural problems. Studies exploring the effect of management and leadership strategies within schools, policies, and aspects of the physical environment other than green space were scarce or absent in the literature. This review highlights the need to consider the ways in which educational settings are organised, the culture that is created and the physical space in order to improve the MH of CYP
A search for periodicity in the light curves of selected blazars
We present an analysis of multifrequency light curves of the sources 2223-052
(3C 446), 2230+114 (CTA 102), and 2251+158 (3C 454.3), which had shown evidence
of quasi-periodic activity. The analysis made use of data from the University
of Michican Radio Astronomy Observatory (USA) at 4.8, 8, and 14.5 GHz, as well
as the Metsahovi Radio Astronomy Observatory (Finland) at 22 and 37 GHz.
Application of two different methods (the discrete autocorrelation function and
the method of Jurkevich) both revealed evidence for periodicity in the flux
variations of these sources at essentially all frequencies. The periods derived
for at least two of the sources -- 2223-052 and 2251+158-- are in good
agreement with the time interval between the appearance of successive VLBI
components. The derived periods for 2251+158 (P = 12.4 yr and 2223-052 (P = 5.8
yr) coincide with the periods found earlier by other authors based on optical
light curves.Comment: 27 pages, 11 figures, accepted for publication in Astronomy Report
A possible jet precession in the periodic quasar B0605-085
The quasar B0605-085 (OH 010) shows a hint for probable periodical
variability in the radio total flux-density light curves. We study the possible
periodicity of B0605-085 in the total flux-density, spectra and opacity changes
in order to compare it with jet kinematics on parsec scales. We have analyzed
archival total flux-density variability at ten frequencies (408 MHz, 4.8 GHz,
6.7 GHz, 8 GHz, 10.7 GHz, 14.5 GHz, 22 GHz, 37 GHz, 90 GHz, and 230 GHz)
together with the archival high-resolution very long baseline interferometry
data at 15 GHz from the MOJAVE monitoring campaign. Using the Fourier transform
and discrete autocorrelation methods we have searched for periods in the total
flux-density light curves. In addition, spectral evolution and changes of the
opacity have been analyzed. We found a period in multi-frequency total
flux-density light curves of 7.9+-0.5 yrs. Moreover, a quasi-stationary jet
component C1 follows a prominent helical path on a similar time scale of 8
years. We have also found that the average instantaneous speeds of the jet
components show a clear helical pattern along the jet with a characteristic
scale of 3 mas. Taking into account average speeds of jet components, this
scale corresponds to a time scale of about 7.7 years. Jet precession can
explain the helical path of the quasi-stationary jet component C1 and the
periodical modulation of the total flux-density light curves. We have fitted a
precession model to the trajectory of the jet component C1, with a viewing
angle phi=2.6+-2.2 degrees, aperture angle of the precession cone
Omega=23.9+-1.9 degrees and fixed precession period (in the observers frame) P
= 7.9 yrs.Comment: 14 pages, 16 figures, 5 tables, accepted for publication in A&
An upper limit for the water outgassing rate of the main-belt comet 176P/LINEAR observed with Herschel/HIFI
176P/LINEAR is a member of the new cometary class known as main-belt comets
(MBCs). It displayed cometary activity shortly during its 2005 perihelion
passage that may be driven by the sublimation of sub-surface ices. We have
therefore searched for emission of the H2O 110-101 ground state rotational line
at 557 GHz toward 176P/LINEAR with the Heterodyne Instrument for the Far
Infrared (HIFI) on board the Herschel Space Observatory on UT 8.78 August 2011,
about 40 days after its most recent perihelion passage, when the object was at
a heliocentric distance of 2.58 AU. No H2O line emission was detected in our
observations, from which we derive sensitive 3-sigma upper limits for the water
production rate and column density of < 4e25 molec/s and of < 3e10 cm^{-2},
respectively. From the peak brightness measured during the object's active
period in 2005, this upper limit is lower than predicted by the relation
between production rates and visual magnitudes observed for a sample of comets
by Jorda et al. (2008) at this heliocentric distance. Thus, 176P/LINEAR was
likely less active at the time of our observation than during its previous
perihelion passage. The retrieved upper limit is lower than most values derived
for the H2O production rate from the spectroscopic search for CN emission in
MBCs.Comment: 5 pages, 2 figures. Minor changes to match published versio
Testing the comet nature of main belt comets. The spectra of 133P/Elst-Pizarro and 176P/LINEAR
We present the visible spectrum of MBCs 133P/Elst-Pizarro and 176P/LINEAR, as
well as three Themis family asteroids: (62) Erato, (379), Huenna and (383)
Janina, obtained in 2007 using three telescopes at "El Roque de los Muchachos"'
Observatory, in La Palma, Spain, and the 8m Kueyen (UT2) VLT telescope at Cerro
Paranal, Chile.
The spectra of 133P and 176P resemble best those of B-type asteroid and are
very similar to those of Themis family members and are significantly different
from the spectrum of comet 162P/Siding-Spring and most of the observed cometary
nuclei. CN gas emission is not detected in the spectrum of 133P. We determine
an upper limit for the CN production rate Q(CN) = mol/s,
three orders of magnitude lower than the Q(CN) of Jupiter family comets
observed at similar heliocentric distances.
The spectra of 133P/Elst-Pizarro and 176P/LINEAR confirm that they are likely
members of the Themis family of asteroids, fragments that probably retained
volatiles, and unlikely have a cometary origin in the trans-neptunian belt or
the Oort cloud.Comment: Paper sumbmited to A&A. 7 pages and 6 figure
- …