12,478 research outputs found
The ability of fifth grade children to discriminate between fact and opinion statement
Thesis (Ed.M.)--Boston Universit
Dualities Compositeness and Spacetime Structure of 4d Extreme Stringy Black Holes
We study the BPS black hole solutions of the (truncated) action for heterotic
string theory compactified on a six-torus. The O(3,Z) duality symmetry of the
theory, together with the bound state interpretation of extreme black holes, is
used to generate the whole spectrum of the solutions. The corresponding
spacetime structures, written in terms of the string metric, are analyzed in
detail. In particular, we show that only the elementary solutions present naked
singularities. The bound states have either null singularities (electric
solutions) or are regular (magnetic or dyonic solutions) with near-horizon
geometries given by the product of two 2d spaces of constant curvature. The
behavior of some of these solutions as supersymmetric attractors is discussed.
We also show that our approach is very useful to understand some of the
puzzling features of charged black hole solutions in string theory.Comment: 17 pages, LaTex, no figure
Supergravity Predictions on Conformal Field Theories
We give an update on recent results about the matching between CFT operators
and KK states in the AdS/CFT correspondence, and add some new comments on the
realization of the baryonic symmetries from the supergravity point of view.Comment: 8 pages, uses JHEP.cls, Contribution to the proceedings of the TMR
Conference on Quantum Aspects of Gauge Theories, Supersymmetry and
Unification, Paris, 1-7 September 199
M Theory on the Stiefel manifold and 3d Conformal Field Theories
We compute the mass and multiplet spectrum of M theory compactified on the
product of AdS(4) spacetime by the Stiefel manifold V(5,2)=SO(5)/SO(3), and we
use this information to deduce via the AdS/CFT map the primary operator content
of the boundary N=2 conformal field theory. We make an attempt for a candidate
supersymmetric gauge theory that, at strong coupling, should be related to
parallel M2-branes on the singular point of the non-compact Calabi-Yau
four-fold , describing the cone on V(5,2).Comment: Latex, 28 page
Tailoring therapy for heart failure: the pharmacogenomics of adrenergic receptor signaling.
Heart failure is one of the leading causes of mortality in Western countries, and β-blockers are a cornerstone of its treatment. However, the response to these drugs is variable among individuals, which might be explained, at least in part, by genetic differences. Pharmacogenomics is the study of genetic contributions to drug response variability in order to provide evidence for a tailored therapy in an individual patient. Several studies have investigated the pharmacogenomics of the adrenergic receptor system and its role in the context of the use of β-blockers in treating heart failure. In this review, we will focus on the most significant polymorphisms described in the literature involving adrenergic receptors and adrenergic receptor-related proteins, as well as genetic variations influencing β-blocker metabolism
Combination formoterol and budesonide as maintenance and reliever therapy versus combination inhaler maintenance for chronic asthma in adults and children.
BACKGROUND: Asthma is characterised by chronic inflammation of the airways and recurrent exacerbations with wheezing, chest tightness and cough. Treatment with inhaled steroids and bronchodilators often results in good control of symptoms, prevention of further morbidity and mortality and improved quality of life. Several steroids and beta2-agonists (long- and short-acting) as well as combinations of these treatments are available in a single inhaler to be used once or twice a day, with a separate inhaler for relief of symptoms when needed (for patients in Step three or higher, according to Global Initiative for Asthma (GINA) guidelines). Budesonide/formoterol is also licenced for use as maintenance and reliever therapy from a single inhaler (SiT; sometimes referred to as SMART therapy). SiT can be prescribed at a lower dose than other combination therapy because of the additional steroid doses being received as reliever therapy. It has been suggested that using SiT improves compliance and hence reduces symptoms and exacerbations, but it is unclear whether it increases side effects associated with the use of inhaled steroids. OBJECTIVES: To assess the efficacy and safety of budesonide/formoterol in a single inhaler (SiT) to be used for both maintenance and reliever therapy in asthma in comparison with maintenance treatment provided through combination inhalers with a higher maintenance steroid dose (either fluticasone/salmeterol or budesonide/formoterol), along with additional fast-acting beta2-agonists for relief of symptoms. SEARCH METHODS: We searched the Cochrane Airways Group Specialised Register of trials, online trial registries and drug company websites. The most recent search was conducted in November 2013. SELECTION CRITERIA: We included parallel-group, randomised controlled trials of at least 12 weeks' duration. Studies were included if they compared single-inhaler therapy with budesonide/formoterol (SiT) versus combination inhalers at a higher maintenance dose of steroids than was given in the SiT arm (either salmeterol/fluticasone or budesonide/formoterol). DATA COLLECTION AND ANALYSIS: We used standard methods expected by The Cochrane Collaboration. Primary outcomes were exacerbations requiring hospitalisation, exacerbations requiring oral corticosteroids and serious adverse events (including mortality). MAIN RESULTS: Four studies randomly assigning 9130 people with asthma were included; two were six-month double-blind studies, and two were 12-month open-label studies. No trials included children younger than age 12. Trials included more women than men, with mean age ranging from 38 to 45, and mean baseline steroid dose (inhaled beclomethasone (BDP) equivalent) from 636 to 888 μg. Mean baseline forced expiratory volume in one second (FEV1) percentage predicted was between 70% and 73% in three of the trials, and 96% in another. All studies were funded by AstraZeneca and were generally free from methodological biases, although the two open-label studies were rated as having high risk for blinding, and some evidence of selective outcome reporting was found. These possible sources of bias did not lead us to downgrade the quality of the evidence. The quantity of inhaled steroids, including puffs taken for relief from symptoms, was consistently lower for SiT than for the comparison groups.Separate data for exacerbations leading to hospitalisations, to emergency room (ER) visits or to a course of oral steroids could not be obtained. Compared with higher fixed-dose combination inhalers, fewer people using SiT had exacerbations requiring hospitalisation or a visit to the ER (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.57 to 0.90; I(2) = 0%, P = 0.66), and fewer had exacerbations requiring a course of oral corticosteroids (OR 0.75, 95% CI 0.65 to 0.87; I(2) = 0%, P = 0.82). This translates to one less person admitted to hospital or visiting the ER (95% CI 0 to 2 fewer) and two fewer people needing oral steroids (95% CI 1 to 3 fewer) compared with fixed-dose combination treatment with a short-acting beta-agonist (SABA) reliever (per 100 treated over eight months). No statistical heterogeneity was observed in either outcome, and the evidence was rated of high quality. Although issues with blinding were evident in two of the studies, and one study recruited a less severe population, sensitivity analyses did not change the main results, so quality was not downgraded.We could not rule out the possibility that SiT increased rates of serious adverse events (OR 0.92, 95% CI 0.74 to 1.13; I(2) = 0%, P = 0.98; moderate-quality evidence, downgraded owing to imprecision).We were unable to say whether SiT improved results for several secondary outcomes (morning and evening peak expiratory flow (PEF), rescue medication use, symptoms scales), and in cases where results were significant, the effect sizes were not considered clinically meaningful (predose FEV1, nocturnal awakenings and quality of life). AUTHORS' CONCLUSIONS: SiT reduces the number of people having asthma exacerbations requiring oral steroids and the number requiring hospitalisation or an ER visit compared with fixed-dose combination inhalers. Evidence for serious adverse events was unclear. The mean daily dose of inhaled corticosteroids (ICS) in SiT, including the total dose administered with reliever use, was always lower than that of the other combination groups. This suggests that the flexibility in steroid administration that is possible with SiT might be more effective than a standard fixed-dose combination by increasing the dose only when needed and keeping it low during stable stages of the disease. Data for hospitalisations alone could not be obtained, and no studies have yet addressed this question in children younger than age 12
Initial mass function of intermediate mass black hole seeds
We study the Initial Mass Function (IMF) and host halo properties of
Intermediate Mass Black Holes (IMBH, 10^{4-6} Msun) formed inside metal-free,
UV illuminated atomic cooling haloes (virial temperature T_vir > 10^4 K) either
via the direct collapse of the gas or via an intermediate Super Massive Star
(SMS) stage. We achieve this goal in three steps: (a) we derive the gas
accretion rate for a proto-SMS to undergo General Relativity instability and
produce a direct collapse black hole (DCBH) or to enter the ZAMS and later
collapse into a IMBH; (b) we use merger-tree simulations to select atomic
cooling halos in which either a DCBH or SMS can form and grow, accounting for
metal enrichment and major mergers that halt the growth of the proto-SMS by gas
fragmentation. We derive the properties of the host halos and the mass
distribution of black holes at this stage, and dub it the "Birth Mass
Function"; (c) we follow the further growth of the DCBH due to accretion of
leftover gas in the parent halo and compute the final IMBH mass.We consider two
extreme cases in which minihalos (T_vir < 10^4 K) can (fertile) or cannot
(sterile) form stars and pollute their gas leading to a different IMBH IMF. In
the (fiducial) fertile case the IMF is bimodal extending over a broad range of
masses, M= (0.5-20)x10^5 Msun, and the DCBH accretion phase lasts from 10 to
100 Myr. If minihalos are sterile, the IMF spans the narrower mass range M=
(1-2.8)x10^6 Msun, and the DCBH accretion phase is more extended (70-120 Myr).
We conclude that a good seeding prescription is to populate halos (a) of mass
7.5 < log (M_h/Msun) < 8, (b) in the redshift range 8 < z < 17, (c) with IMBH
in the mass range 4.75 < log (M_BH/Msun) < 6.25.Comment: MNRAS, in press. Comments welcom
Tuberculosis of the tongue in a patient with rheumatoid arthritis treated with methotrexate and adalimumab.
Black Hole Superpartners and Fixed Scalars
Some bosonic solutions of supergravities admit Killing spinors of unbroken
supersymmetry. The anti-Killing spinors of broken supersymmetry can be used to
generate the superpartners of stringy black holes. This has a consequent
feedback on the metric and the graviphoton. We have found however that the
fixed scalars for the black hole superpartners remain the same as for the
original black holes. Possible phenomenological implications of this result are
discussed.Comment: 6 pages, Late
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