704 research outputs found
Status of QCD
I have been asked to discuss the status of QCD. It seems to me that there are
three main points to be made about the present status of QCD: QCD is
right, and we can do many beautiful things with it. There are several
important concrete problems that lie just beyond the edge of our current
understanding. There are some foundational issues in QCD, and some
recent developments, that may point toward entirely new directions. These
points will, I believe, emerge quite clearly from the following more detailed
discussion. The discussion will be in three parts. I'll first discuss
elementary processes, then more complicated processes, and then finally
foundational issues.Comment: 28 pages, use Phyzzx, figures available by FAX or mail on request,
IASSNS-HEP-93/6
Vacuum Stability, Perturbativity, and Scalar Singlet Dark Matter
We analyze the one-loop vacuum stability and perturbativity bounds on a
singlet extension of the Standard Model (SM) scalar sector containing a scalar
dark matter candidate. We show that the presence of the singlet-doublet quartic
interaction relaxes the vacuum stability lower bound on the SM Higgs mass as a
function of the cutoff and lowers the corresponding upper bound based on
perturbativity considerations. We also find that vacuum stability requirements
may place a lower bound on the singlet dark matter mass for given singlet
quartic self coupling, leading to restrictions on the parameter space
consistent with the observed relic density. We argue that discovery of a light
singlet scalar dark matter particle could provide indirect information on the
singlet quartic self-coupling.Comment: 25 pages, 10 figures; v2 - fixed minor typos; v3 - added to text
discussions of other references, changed coloring of figures for easier black
and white viewin
Effects of 3% trehalose as an adjuvant treatment after lasik
Purpose: To evaluate the effect of 3% trehalose as an adjuvant in the standard treatment after laser-assisted in situ keratomileusis. Design: Interventional prospective comparative single-blind study. Setting: Department of Ophthalmology, Hospital Quirón Zaragoza, Spain. Methods: A total of 26 eyes (13 patients) were included, of which 12 eyes (group 1) received conventional treatment with lubricant drops of hyaluronic acid (0.15%) and 14 eyes (group 2) received, additionally, an ophthalmic solution of 3% trehalose. Pre- and postoperative quality-of-life tests and vital stains, tear breakup time, and osmolarity measurements were made. Results: We obtained statistically significant differences between the groups in the Symptom Assessment in Dry Eye test in all visits with respect to severity, and in the postoperative day 1 visit with respect to frequency, in all cases favoring the trehalose treatment. The values of osmolarity were not significantly different between groups. However, we did find significant differences in the Oxford scale in day 90 for the trehalose treatment (P<0.001), and in the National Eye Institute scale in day 30 (P=0.02). Conclusion: The results of this exploratory study indicate that the adjuvant treatment with 3% trehalose could be superior with respect to the standard treatment, with improvements in the objective and subjective parameters of tear quality
Influenza virus infections in infants aged less than two years old
[ES] Introducción: Las infecciones por virus influenza son una importante causa de morbilidad en lactantes. El cuadro clínico es inespecífico y a menudo se infraestima la importancia de lagripe en los menores de 2 años. El objetivo del estudio fue describir las infecciones con firmadas por virus influenza en niños menores de 2 años atendidos en un hospital de segundo nivel. Como objetivo secundario, se pretende comparar las infecciones por gripe en lactantes hospitalizados con las infecciones por virus respiratorio sincitial (VRS) en la misma población. Pacientes y métodos: Estudio descriptivo prospectivo de las infecciones con firmadas por virus influenza en los niños menores de
2 años hospitalizados por fiebre o infección respiratoria entre 1991 y 2003. Para el diagnóstico virológico se realizó inmunofluorescencia y reacción en cadena de la poli merasa en el aspirado nasofaríngeo. Se describen las características clínicas de los pacientes. Se realiza una comparación con un grupo de lactantes de similares características ingresados por infección por VRS. Resultados: Se describen 100 lactantes hospitalizados con infección
por virus influenza. Las infecciones gripales supusieron el 4,1 % de los pacientes hospitalizados por procesos respiratorios o fiebre. Se aisló virus influenza tipo A en el 83 % de los casos, tipo B en el 12 % y tipo C en el 5 %. La
edad media fue 8,3 +/- 5,9 meses, y los diagnósticos más fre cuentes fueron bronquiolitis en el 38 %, sibilancias recurrentes en el 25%, infección respiratoria de vías altas en el 19% y neumonía en el 9%. Presentaron fiebre superior
a 38 °C el 83% de los niños e infiltrado radiológico el 65%. Presentaron hipoxia el 44 % de los niños. En los niños menores de 6 meses la fiebre fue menos frecuente (p = 0,049), y en los diagnósticos predominaron las infecciones respiratorias de vías altas (p = 0,01). Los niños afectados de infección por virus influenza tu vieron mayor edad (p = 0,002), presentaron con mayor frecuencia fiebre (p 38 degrees C was present in 83% of the patients. Radiologic infiltrate was found in 65% of the children. Oxygen saturation less then 95% was present in 44%. In children under 6 months of age fever was less frequent (p = 0.049) and upper respiratory tract infection was more frequent (p = 0.01). Patients with influenza virus infection were older (p = 0.002), more frequently presented fever (p < 0.0001) and radiologic infiltrate (p < 0.001) than infants with RSV infection. Bronchiolitis was more frequent in the RSV group (p = 0.006). Conclusions: Influenza infection is a major cause of respiratory tract disease in hospitalized infants. It is an etiologic cause of bronchiolitis, recurrent wheezing, and fever and radiologic consolidations are frequent. Clinical presentation is milder in children under 6 month of age. The characteristics of influenza infection differ substantially from those of RSV infection.S
Human bocavirus infections in Spanish 0-14 year-old: clinical and epidemiological characteristics of an emerging respiratory virus
[ES] Introducción: En el año 2005 se ha clonado un nuevo virus respiratorio, llamado bocavirus humano (HBoV) de muestras respiratorias procedentes de lactantes y niños suecos con infección respiratoria de vías bajas. Objetivos: Determinar si HBoV ha circulado en España, estimar la frecuencia de infecciones por HBoV en los niños hospitalizados por infección respiratoria y describir sus características clínicas y epidemiológicas. Pacientes y métodos: Estudio descriptivo, prospectivo de las infecciones confirmadas por HBoV en niños menores de 14 años, hospitalizados por infección respiratoria desde octubre de 2004 a junio de 2005. Para el diagnóstico virológico se realizó reacción en cadena de la polimerasa-transcripción inversa (RT-PCR) múltiple para virus respiratorio sincitial (VRS) A y B, influenza A, B y C, parainfluenza 1-4, adenovirus y rinovirus; PCR para metapneumovirus humano (hMPV) y PCR para HBoV en aspirado nasofaríngeo. Se describen las características clínicas y epidemiológicas de los pacientes. Resultados: Se detectaron 52 casos de infección por HBoV, lo que supuso el 17,1 % (IC [intervalo de confianza] 95 %: 13 a 21) de los pacientes hospitalizados por procesos respiratorios. HBoV fue el tercer agente viral tras el VRS (30 %) y el rinovirus (25 %). En 39 casos (71,1 %) se detectó coinfección con otro virus respiratorio. El 50 % de los pacientes eran menores de 13,6 meses y el 75% menores de 2 años. Los diagnósticos más frecuentes fueron sibilancias recurrentes (55,8 %), bronquiolitis (21,2 %) y neumonía (15,4 %). Dos niños presentaron sepsis clínica con exantema petequial. El 71,2 % presentó fiebre superior a 38 °C e infiltrado radiológico el 44 %. Presentaron hipoxia el 55,8 % de los niños. Dos pacientes presentaron aislamientos positivos para HBoV en distintos episodios. Las coinfecciones fueron similares a las infecciones simples, excepto que presentaron hipoxia con más frecuencia, p = 0,038. Conclusiones: HBoV es uno de los virus más frecuentes en las infecciones respiratorias graves de los niños, sólo precedido por VRS y rinovirus. Las coinfecciones son muy frecuentes. La mayoría de los niños son lactantes con sibilancias recurrentes y bronquiolitis. [EN] Introduction: In 2005 a new respiratory virus, called human bocavirus (HBoV), was cloned from respiratory samples from Swedish infants and children with lower respiratory tract infections. Objectives: To determine whether HBoV has circulated in Spain, estimate the frequency of HBoV infections in patients hospitalized for respiratory infection and describe the clinical and epidemiological characteristics of these patients. Patients and methods: We performed a descriptive prospective study of confirmed HBoV infections in patients aged 38 degrees C was found in 72.1% and radiological infiltrate in 44%. Hypoxia was present in 55.8 % of the patients. HBoV was isolated in distinct episodes in two patients. Coinfections were similar to simple infections except that hypoxia was more frequent in the former (p = 0.038). Conclusions: HBoV is one of the most frequent viruses in severe respiratory infections in patients aged less than 14 years old. Only RSV and rhinovirus are more frequent. Coinfections are highly frequent. Most patients are infants with recurrent wheezing and bronchiolitis.Estudio parcialmente financiado por el Fondo de Investigaciones Sanitarias. FIS N.º 98/0310.S
Losing the media battle, waging the policy war: The pharmaceutical industry’s response to the access to medicines crisis in the Global South
This article sheds new light on the pharmaceutical industry’s response to the public relations crisis generated by the global civil society campaign for access to HIV/AIDS medicines since the early 2000s – one of the most contentious policy areas of global trade and health governance. Drawing on interviews with industry insiders, the article explores the industry’s communicative agency in both the media sphere and key sites of power, with a focus on the European Union (EU) policy sphere. The analysis shows that the industry has focused primarily on maintaining access to policymakers and sustaining elite consensus around the existing global intellectual property rights regime through political communication activities that largely bypass mediated public arenas – from strategically promoting its corporate social responsibility (CSR) programmes and mobilizing third-party endorsement to direct lobbying. The article concludes by reflecting on the implications of the findings for critical investigations of the interplay between media and political power in relation to global economic governance
Seesaw Neutrino Signals at the Large Hadron Collider
We discuss the scenario with gauge singlet fermions (right-handed neutrinos)
accessible at the energy of the Large Hadron Collider. The singlet fermions
generate tiny neutrino masses via the seesaw mechanism and also have sizable
couplings to the standard-model particles. We demonstrate that these two facts,
which are naively not satisfied simultaneously, are reconciled in the
five-dimensional framework in various fashions, which make the seesaw mechanism
observable. The collider signal of tri-lepton final states with transverse
missing energy is investigated for two explicit examples of the observable
seesaw, taking account of three types of neutrino mass spectrum and the
constraint from lepton flavor violation. We find by showing the significance of
signal discovery that the collider experiment has a potential to find signals
of extra dimensions and the origin of small neutrino masses.Comment: 27 pages, 4 figure
Clinical relevance of postzygotic mosaicism in Cornelia de Lange syndrome and purifying selection of NIPBL variants in blood
Postzygotic mosaicism (PZM) in NIPBL is a strong source of causality for Cornelia de Lange syndrome (CdLS) that can have major clinical implications. Here, we further delineate the role of somatic mosaicism in CdLS by describing a series of 11 unreported patients with mosaic disease-causing variants in NIPBL and performing a retrospective cohort study from a Spanish CdLS diagnostic center. By reviewing the literature and combining our findings with previously published data, we demonstrate a negative selection against somatic deleterious NIPBL variants in blood. Furthermore, the analysis of all reported cases indicates an unusual high prevalence of mosaicism in CdLS, occurring in 13.1% of patients with a positive molecular diagnosis. It is worth noting that most of the affected individuals with mosaicism have a clinical phenotype at least as severe as those with constitutive pathogenic variants. However, the type of genetic change does not vary between germline and somatic events and, even in the presence of mosaicism, missense substitutions are located preferentially within the HEAT repeat domain of NIPBL. In conclusion, the high prevalence of mosaicism in CdLS as well as the disparity in tissue distribution provide a novel orientation for the clinical management and genetic counselling of families
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