1,846 research outputs found
Leptophobic U(1)'s and the R_b - R_c Crisis
In this paper, we investigate the possibility of explaining both the R_b
excess and the R_c deficit reported by the LEP experiments through Z-Z' mixing
effects. We have constructed a set of models consistent with a restrictive set
of principles: unification of the Standard Model (SM) gauge couplings, vector-
like additional matter, and couplings which are both generation-independent and
leptophobic. These models are anomaly-free, perturbative up to the GUT scale,
and contain realistic mass spectra. Out of this class of models, we find three
explicit realizations which fit the LEP data to a far better extent than the
unmodified SM or MSSM and satisfy all other phenomenological constraints which
we have investigated. One realization, the \eta-model coming from E_6, is
particularly attractive, arising naturally from geometrical compactifications
of heterotic string theory. This conclusion depends crucially on the inclusion
of a U(1) kinetic mixing term, whose value is correctly predicted by
renormalization group running in the E_6 model given one discrete choice of
spectra.Comment: LaTeX, 26 pages, 5 embedded EPSF figures. Version to be published in
Phys. Rev.
The Pediatric Obsessive-Compulsive Disorder Treatment Study II: rationale, design and methods
This paper presents the rationale, design, and methods of the Pediatric Obsessive-Compulsive Disorder Treatment Study II (POTS II), which investigates two different cognitive-behavior therapy (CBT) augmentation approaches in children and adolescents who have experienced a partial response to pharmacotherapy with a serotonin reuptake inhibitor for OCD. The two CBT approaches test a "single doctor" versus "dual doctor" model of service delivery. A specific goal was to develop and test an easily disseminated protocol whereby child psychiatrists would provide instructions in core CBT procedures recommended for pediatric OCD (e.g., hierarchy development, in vivo exposure homework) during routine medical management of OCD (I-CBT). The conventional "dual doctor" CBT protocol consists of 14 visits over 12 weeks involving: (1) psychoeducation, (2), cognitive training, (3) mapping OCD, and (4) exposure with response prevention (EX/RP). I-CBT is a 7-session version of CBT that does not include imaginal exposure or therapist-assisted EX/RP. In this study, we compared 12 weeks of medication management (MM) provided by a study psychiatrist (MM only) with two types of CBT augmentation: (1) the dual doctor model (MM+CBT); and (2) the single doctor model (MM+I-CBT). The design balanced elements of an efficacy study (e.g., random assignment, independent ratings) with effectiveness research aims (e.g., differences in specific SRI medications, dosages, treatment providers). The study is wrapping up recruitment of 140 youth ages 7â17 with a primary diagnosis of OCD. Independent evaluators (IEs) rated participants at weeks 0,4,8, and 12 during acute treatment and at 3,6, and 12 month follow-up visits
Developing a model of mental health self-care support for children and young people through an integrated evaluation of available types of provision involving systematic review, meta-analysis and case study
Background
The mental health of children and young people (CYP) is a major UK public health concern. Recent policy reviews have identified that service provision for CYP with mental health needs is not as effective, responsive, accessible or child-centred as it could be. Following on from a previous National Institute for Health Research (NIHR) study into self-care support for CYP with long-term physical health needs, this study explored self-care supportâs potential in CYPâs mental health.
Objectives
To identify and evaluate the types of mental health self-care support used by, and available to, CYP and their parents, and to establish how such support interfaces with statutory and non-statutory service provision.
Design
Two inter-related systematic literature reviews (an effectiveness review with meta-analysis and a perceptions review), together with a service mapping exercise and case study.
Setting
Global (systematic reviews); England and Wales (mapping exercise and case study).
Participants (case study)
Fifty-two individuals (17 CYP, 16 family members and 19 staff) were interviewed across six sites.
Main outcome measures (meta-analysis)
A measure of CYPâs mental health symptomatology.
Data sources (literature reviews)
MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, All Evidence-Based Medicine (EBM) Reviews, Applied Social Sciences Index and Abstracts (ASSIA) and Education Resources Information Center (ERIC).
Review methods
Titles and abstracts of papers were screened for relevance then grouped into studies. Two independent reviewers extracted data from studies meeting the inclusion criteria. A descriptive analysis and meta-analysis were conducted for the effectiveness review; descriptive analyses were conducted for the perceptions review. These analyses were integrated to elicit a mixed-methods review.
Results
Sixty-five of 71 included studies were meta-analysable. These 65 studies elicited 71 comparisons which, when meta-analysed, suggested that self-care support interventions were effective at 6-month [standardised mean difference (SMD)â=ââ0.20; 95% confidence interval (CI) â0.28 to â0.11] and 12-month (SMDâ=ââ0.12; 95% CI â0.17 to â0.06) follow-ups. However, judged against Cochrane criteria, the studies were mostly low quality. Key elements of self-care support identified in the perceptions review were the acquisition of knowledge and skills, peer support and the relationship with the self-care support agent; CYP also had different perceptions from adults about what is important in self-care support. The mapping exercise identified 27 providers of 33 self-care support services. According to the case study data, effective self-care support services are predicated on flexibility; straightforward access; non-judgemental, welcoming organisations and staff; the provision of time and attention; opportunities to learn and practise skills relevant to self-care; and systems of peer support.
Conclusions
Mental health self-care support interventions for CYP are modestly effective in the short to medium term. Self-care support can be conceptualised as a process which has overlap with ârecoveryâ. CYP and their families want choice and flexibility in the provision of such interventions and a continued relationship with services after the nominal therapy period. Those delivering self-care support need to have specific child-centred attributes.
Future work
Future work should focus on under-represented conditions (e.g. psychosis, eating disorders, self-harm); the role of technology, leadership and readiness in self-care support; satisfaction in self-care support; the conceptualisation of self-care support in CYPâs mental health; and efficacy and cost-effectiveness
Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing
Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on
coarse measurements of spectral energy distributions in a few filters to
estimate the redshift distribution of source galaxies. In this regime, sample
variance, shot noise, and selection effects limit the attainable accuracy of
redshift calibration and thus of cosmological constraints. We present a new
method to combine wide-field, few-filter measurements with catalogs from deep
fields with additional filters and sufficiently low photometric noise to break
degeneracies in photometric redshifts. The multi-band deep field is used as an
intermediary between wide-field observations and accurate redshifts, greatly
reducing sample variance, shot noise, and selection effects. Our implementation
of the method uses self-organizing maps to group galaxies into phenotypes based
on their observed fluxes, and is tested using a mock DES catalog created from
N-body simulations. It yields a typical uncertainty on the mean redshift in
each of five tomographic bins for an idealized simulation of the DES Year 3
weak-lensing tomographic analysis of , which is a
60% improvement compared to the Year 1 analysis. Although the implementation of
the method is tailored to DES, its formalism can be applied to other large
photometric surveys with a similar observing strategy.Comment: 24 pages, 11 figures; matches version accepted to MNRA
Objective comparison of methods to decode anomalous diffusion
Deviations from Brownian motion leading to anomalous diffusion are found in transport dynamics from quantum physics to life sciences. The characterization of anomalous diffusion from the measurement of an individual trajectory is a challenging task, which traditionally relies on calculating the trajectory mean squared displacement. However, this approach breaks down for cases of practical interest, e.g., short or noisy trajectories, heterogeneous behaviour, or non-ergodic processes. Recently, several new approaches have been proposed, mostly building on the ongoing machine-learning revolution. To perform an objective comparison of methods, we gathered the community and organized an open competition, the Anomalous Diffusion challenge (AnDi). Participating teams applied their algorithms to a commonly-defined dataset including diverse conditions. Although no single method performed best across all scenarios, machine-learning-based approaches achieved superior performance for all tasks. The discussion of the challenge results provides practical advice for users and a benchmark for developers
Beyond the standard seesaw: neutrino masses from Kahler operators and broken supersymmetry
We investigate supersymmetric scenarios in which neutrino masses are
generated by effective d=6 operators in the Kahler potential, rather than by
the standard d=5 superpotential operator. First, we discuss some general
features of such effective operators, also including SUSY-breaking insertions,
and compute the relevant renormalization group equations. Contributions to
neutrino masses arise at low energy both at the tree level and through finite
threshold corrections. In the second part we present simple explicit
realizations in which those Kahler operators arise by integrating out heavy
SU(2)_W triplets, as in the type II seesaw. Distinct scenarios emerge,
depending on the mechanism and the scale of SUSY-breaking mediation. In
particular, we propose an appealing and economical picture in which the heavy
seesaw mediators are also messengers of SUSY breaking. In this case, strong
correlations exist among neutrino parameters, sparticle and Higgs masses, as
well as lepton flavour violating processes. Hence, this scenario can be tested
at high-energy colliders, such as the LHC, and at lower energy experiments that
measure neutrino parameters or search for rare lepton decays.Comment: LaTeX, 34 pages; some corrections in Section
Similar Dark Matter and Baryon abundances with TeV-scale Leptogenesis
We estimate the Baryon Asymmetry of the Universe (BAU) produced in an inverse
seesaw model containing extra light singlets, and with lepton number
conservation prior to the electroweak phase transition. An order one CP
asymmetry epsilon is required to obtain a large enough BAU. We discuss the
relation between the baryon and WIMP relic densities in baryogenesis scenarios
using the out-of-equilibrium decay of a baryon-parent of mass M: when baryon
number violation freezes out, the remaining density of baryon-parents is of
order M/m_W times the WIMP relic density. So the baryon/WIMP ratio is or order
epsilon M/m_W. A natural explanation of the similar WIMP and baryon densities
could be that CP violation is of order the ratio m_W/M.Comment: references adde
A functional alternative splicing mutation in human tryptophan hydroxylase-2
The brain serotonergic system has an essential role in the physiological functions of the central nervous system and dysregulation of serotonin (5-HT) homeostasis has been implicated in many neuropsychiatric disorders. The tryptophan hydroxylase-2 (TPH2) gene is the rate-limiting enzyme in brain 5-HT synthesis, and thus is an ideal candidate gene for understanding the role of dysregulation of brain serotonergic homeostasis. Here, we characterized a common, but functional single-nucleotide polymorphism (SNP rs1386493) in the TPH2 gene, which decreases efficiency of normal RNA splicing, resulting in a truncated TPH2 protein (TPH2-TR) by alternative splicing. TPH2-TR, which lacks TPH2 enzyme activity, dominant-negatively affects full-length TPH2 function, causing reduced 5-HT production. The predicted mRNA for TPH2-TR is present in postmortem brain of rs1386493 carriers. The rs13864923 variant does not appear to be overrepresented in either global or multiplex depression cohorts. However, in combination with other gene variants linked to 5-HT homeostasis, this variant may exhibit important epistatic influences
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at âs = 7 TeV with the ATLAS detector
This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of âs = 7 TeV;{\rm Te}{\rm V}4.6\;{\rm f}{{{\rm b}}^{-1}}{{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}|\eta |\lt 1.9{{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques
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