17 research outputs found
The transmission spectrum of Earth through lunar eclipse observations
Of the 342 planets discovered so far orbiting other stars, 58 "transit" the
stellar disk, meaning that they can be detected by a periodic decrease in the
starlight flux. The light from the star passes through the atmosphere of the
planet, and in a few cases the basic atmospheric composition of the planet can
be estimated. As we get closer to finding analogues of Earth, an important
consideration toward the characterization of exoplanetary atmospheres is what
the transmission spectrum of our planet looks like. Here we report the optical
and near-infrared transmission spectrum of the Earth, obtained during a lunar
eclipse. Some biologically relevant atmospheric features that are weak in the
reflected spectrum (such as ozone, molecular oxygen, water, carbon dioxide and
methane) are much stronger in the transmission spectrum, and indeed stronger
than predicted by modelling. We also find the fingerprints of the Earth's
ionosphere and of the major atmospheric constituent, diatomic nitrogen (N2),
which are missing in the reflected spectrum.Comment: Published in Nature, 11 July 2009. This file also contains the
on-line materia
Health care and societal costs of the management of children and adolescents with attention-deficit/hyperactivity disorder in Spain: a descriptive analysis.
Background: Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition in childhood (5.3% to 7.1% worldwide prevalence), with substantial overall financial burden to children/adolescents, their families, and society. The aims of this study were to describe the clinical characteristics of children and adolescents with ADHD in Spain, estimate the associated direct/indirect costs of the disorder, and assess whether the characteristics and financial costs differed between children/adolescents adequately responding to currently available pharmacotherapies compared with children/adolescents for whom pharmacotherapies failed. Methods: This was a multicenter, cross-sectional, descriptive analysis conducted in 15 health units representative of the overall Spanish population. Data on demographic characteristics, socio-occupational status, social relationships, clinical variables of the disease, and pharmacological and non-pharmacological treatments received were collected in 321 children and adolescents with ADHD. Direct and indirect costs were estimated over one year from both a health care system and a societal perspective. Results: The estimated average cost of ADHD per year per child/adolescent was ¿5733 in 2012 prices; direct costs accounted for 60.2% of the total costs (¿3450). Support from a psychologist/educational psychologist represented 45.2% of direct costs and 27.2% of total costs. Pharmacotherapy accounted for 25.8% of direct costs and 15.5% of total costs. Among indirect costs (¿2283), 65.2% was due to caregiver expenses. The total annual costs were significantly higher for children/adolescents who responded poorly to pharmacological treatment (¿7654 versus ¿5517; P = 0.024), the difference being mainly due to significantly higher direct costs, particularly with larger expenses for non-pharmacological treatment (P = 0.012). Conclusions: ADHD has a significant personal, familial, and financial impact on the Spanish health system and society. Successful pharmacological intervention was associated with lower overall expenses in the management of the disorder
The Detectability of Earth's Biosignatures Across Time
Over the past two decades, enormous advances in the detection of exoplanets
have taken place. Currently, we have discovered hundreds of earth-sized
planets, several of them within the habitable zone of their star. In the coming
years, the efforts will concentrate in the characterization of these planets
and their atmospheres to try to detect the presence of biosignatures. However,
even if we discovered a second Earth, it is very unlikely that it would present
a stage of evolution similar to the present-day Earth. Our planet has been far
from static since its formation about 4.5 Ga ago; on the contrary, during this
time, it has undergone multiple changes in it's atmospheric composition, it's
temperature structure, it's continental distribution, and even changes in the
forms of life that inhabit it. All these changes have affected the global
properties of Earth as seen from an astronomical distance. Thus, it is of
interest not only to characterize the observables of the Earth as it is today,
but also at different epochs. Here we review the detectability of the Earth's
globally-averaged properties over time. This includes atmospheric composition
and biosignatures, and surface properties that can be interpreted as sings of
habitability (bioclues). The resulting picture is that truly unambiguous
biosignatures are only detectable for about 1/4 of the Earth's history. The
rest of the time we rely on detectable bioclues that can only establish an
statistical likelihood for the presence of life on a given planet.Comment: To appear in "Handbook of Exoplanets", eds. Deeg, H.J. & Belmonte,
J.A, Springer (2018). arXiv admin note: text overlap with
arXiv:astro-ph/0609398 by other author
Drug discovery in ophthalmology: past success, present challenges, and future opportunities
BACKGROUND: Drug discovery has undergone major transformations in the last century, progressing from the recognition and refinement of natural products with therapeutic benefit, to the systematic screening of molecular libraries on whole organisms or cell lines and more recently to a more target-based approach driven by greater knowledge of the physiological and pathological pathways involved. Despite this evolution increasing challenges within the drug discovery industry are causing escalating rates of failure of development pipelines. DISCUSSION: We review the challenges facing the drug discovery industry, and discuss what attempts are being made to increase the productivity of drug development, including a refocusing on the study of the basic biology of the disease, and an embracing of the concept of ‘translational research’. We consider what ophthalmic drug discovery can learn from the sector in general and discuss strategies to overcome the present limitations. This includes advances in the understanding of the pathogenesis of disease; improvements in animal models of human disease; improvements in ophthalmic drug delivery and attempts at patient stratification within clinical trials. SUMMARY: As we look to the future, we argue that investment in ophthalmic drug development must continue to cover the whole translational spectrum (from ‘bench to bedside and back again’) with recognition that both biological discovery and clinical understanding will drive drug discovery, providing safe and effective therapies for ocular disease
Goldmann applanation tonometry compared with corneal-compensated intraocular pressure in the evaluation of primary open-angle Glaucoma
<p>Abstract</p> <p>Background</p> <p>To better understand the role of corneal properties and intraocular pressure (IOP) in the evaluation of primary open-angle glaucoma (POAG); and to determine the feasibility of identifying glaucomatous optic neuropathy (GON) using IOP corrected and uncorrected for corneal biomechanics.</p> <p>Methods</p> <p>Records from 1,875 eyes of consecutively evaluated new patients were reviewed. Eyes were excluded if central corneal thickness (CCT) or Ocular Response Analyzer (ORA) measurements were unavailable. Presence or absence of GON was determined based on morphology of the optic disc, rim and retinal nerve fiber layer at the time of clinical examination, fundus photography and Heidelberg Retinal Tomography. Goldmann-applanation tonometry (GAT) in the untreated state was recorded and Goldmann-correlated (IOPg) and corneal-compensated IOP (IOPcc) were obtained using the ORA. Glaucomatous eyes were classified as normal or high-tension (NTG, HTG) using the conventional cutoff of 21 mm Hg. One eligible eye was randomly selected from each patient for inclusion.</p> <p>Results</p> <p>A total of 357 normal, 155 HTG and 102 NTG eyes were included. Among NTG eyes, IOPcc was greater than GAT (19.8 and 14.4 mm Hg; p < 0.001) and the difference between IOPcc and GAT was greatest for this subgroup of patients with NTG (p ≤ 0.01). The maximum combined sensitivity and specificity for detection of GON occurred at 20.9 mm Hg for GAT (59%, 90%) and 18.4 mm Hg for IOPcc (85%, 85%) and the area under the curve was greater for IOPcc (0.93 vs. 0.78; p < 0.001).</p> <p>Conclusions</p> <p>IOPcc may account for measurement error induced by corneal biomechanics. Compared to GAT, IOPcc may be a superior test in the evaluation of glaucoma but is unlikely to represent an effective diagnostic test.</p
Prevalence of problematic cell phone use in an adult population in Spain as assessed by the Mobile Phone Problem Use Scale (MPPUS)
Problematic cell phone use has alarmingly increased in industrialized countries in the past 10 years. For many perpetrators, it can turn into a behavioural addiction, although this is not a recognized medical condition. Although there are many tools for evaluating this use, one of the most widely used tools is the Mobile Phone Problematic Use Scale (MPPUS), which we test on a representative sample of the population in Spain to obtain an estimate of the prevalence of problematic cell phone use in our midst. The age range consists of 16-65 years, with 1,126 surveys conducted. In this population, we verify that the reliability and internal consistency of the MPPUS (α = 0.939) are maintained. Additionally, the construct validity, considering the derived factors (Abuse and Dependence, Craving and Loss of Control, and Dependence on the Social Environment) are aligned with other research and with diverse external criteria of addiction. We establish four categories of users (Casual, Regular, At Risk, and Problematic) and obtain a prevalence of 15.4% among At Risk Users and 5.1% among Problematic Users. This finding implies a total of 20.5% of Users with Problems. A binary logistic regression analysis shows that age, gender, level of education, and daily cell phone use predict problematic cell phone use. The results, based on multiple criteria, show that such problematic use shares features of recognized addictions, affecting large segments of the population and not only adolescents