997 research outputs found

    Recursos de ciències al portal edu365.com

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    El portal educatiu edu365.com ofereix a la comunitat educativa recursos que potencien l'autoaprenentatge i afavoreixen el treball col·laboratiu. Es tracta d'una bona col·lecció de materials instructius, accés a enciclopèdies i diaris per a estudiants, espai a la xarxa per publicar treballs, canals de comunicació com el servei de consultoria, el correu electrònic i els xats i la possibilitat de formar grups de treball virtuals a través d'educampus

    Dissipative mean-field theory of IBM utility experiment

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    In spite of remarkable recent advances, quantum computers have not yet found any useful applications. A promising direction for such utility is offered by the simulation of the dynamics of many-body quantum systems, which cannot be efficiently computed classically. Recently, IBM used a superconducting quantum computer to simulate a kicked quantum Ising model for large numbers of qubits and time steps. By employing powerful error mitigation techniques, they were able to obtain an excellent agreement with the exact solution of the model. This result is very surprising, considering that the total error accumulated by the circuit is prohibitively large. In this letter, we address this paradox by introducing a dissipative mean-field approximation based on Kraus operators. Our effective theory reproduces the many-body unitary dynamics and matches quantitatively local and non-local observables. These findings demonstrate that the observed dynamics is equivalent to a single qubit undergoing rotations and dephasing. Our emergent description can explain the success of the quantum computer in solving this specific problem.Comment: 4 pages, 2 figure

    Prevalence and morphometric analysis of the retromolar canal in a Spanish population sample:a helical CT scan study

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    The retromolar canal (RMC) is an anatomical variation of the mandibular canal (MC) whose identification and study should be considered given its implication in the surgical procedures of the retromolar area. The prevalence of the RMC widely varies according to previous studies and may be influenced by the followed study method. This work aimed to evaluate the prevalence of the RMC in a Spanish population sample. For this purpose, 225 CT scan images (with a higher resolution than the cone beam CT used in other previous studies) from the Hospital Clínico Universitario de Valencia were analyzed. The Osirix MD® radiological image analysis system was applied to analyse the dimensions, location in the retromolar area and morphologic characteristics of the RMC by classifying them according to their typology. Furthermore, the relations between the RMC and gender, age and laterality were studied. RMC prevalence was 23.1%. No significant relation between the presence of the canal and gender, age or laterality was found. Type Ia was the commonest type with a prevalence of 40.8%. Based on the results of this study, the RMC should be considered a frequent anatomical variation whose complete study is very important in daily clinical practice

    Evaluation of log Po/w values of drugs from some molecular structure calculation software

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    Predictive software packages to estimate the lipophilicity of molecules have become key tools in the new drug design. Six different well-known computational programs including the classical BioByte-clogP and the GALAS algorithm offered by ACDlabs were evaluated through a set of 103 drugs with different structures and functionalities. To evaluate the predictions accuracy, reliable experimental log Po/w values for the whole testing set were carefully selected. The best estimations are performed by GALAS/logP based on the fragmental method, corrected according to the similarity with compounds included in the software training set

    Acute Respiratory Distress Syndrome Associated With Clopidogrel in a Young Male Patient

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    Background: Clopidogrel is a commonly prescribed antiplatelet drug in patients with stents and histories of arterial vascular disease. It generally has a favorable side effect profile with increasing bleeding risk as the main concern as an adverse event.Case Presentation: A 19-year-old previously healthy male presented to the neurological intensive care unit with a subarachnoid hemorrhage requiring a flow diverting stent to secure the aneurysm. The patient was stable for 2 weeks and had no changes to management or medication within 48 h of antiplatelet therapy. Within hours of first-time dosing of clopidogrel, the patient experienced a syncopal episode and dyspnea. He was difficult to arouse and using accessory muscles to breath with an otherwise benign exam. He was hypoxic with bibasilar crackles requiring bilevel positive airway pressure (BiPap). Imaging showed bilateral pulmonary edema and he was diagnosed with moderate acute respiratory distress syndrome (ARDS). Infectious, cardiogenic, and contrast-induced ARDS were ruled out. Upon cessation of clopidogrel, his pulmonary function and mental status improved.Conclusions: This is the first reported case of a young and immunocompetent patient's severe pulmonary edema leading to acute respiratory distress syndrome in association with first- time dosing of clopidogrel

    Histiocytoid cardiomyopathy and microphthalmia with linear skin defects syndrome: phenotypes linked by truncating variants in NDUFB11

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    Variants in NDUFB11, which encodes a structural component of complex I of the mitochondrial respiratory chain (MRC), were recently independently reported to cause histiocytoid cardiomyopathy (histiocytoid CM) and microphthalmia with linear skin defects syndrome (MLS syndrome). Here we report an additional case of histiocytoid CM, which carries a de novo nonsense variant in NDUFB11 (ENST00000276062.8: c.262C > T; p.[Arg88*]) identified using whole-exome sequencing (WES) of a family trio. An identical variant has been previously reported in association with MLS syndrome. The case we describe here lacked the diagnostic features of MLS syndrome, but a detailed clinical comparison of the two cases revealed significant phenotypic overlap. Heterozygous variants in HCCS (which encodes an important mitochondrially targeted protein) and COX7B, which, like NDUFB11, encodes a protein of the MRC, have also previously been identified in MLS syndrome including a case with features of both MLS syndrome and histiocytoid CM. However, a systematic review of WES data from previously published histiocytoid CM cases, alongside four additional cases presented here for the first time, did not identify any variants in these genes. We conclude that NDUFB11 variants play a role in the pathogenesis of both histiocytoid CM and MLS and that these disorders are allelic (genetically related)

    El colesterol sigue alto. ¿Y ahora qué hacemos? Tratamiento de la hipercolesteremia no controlada a lo largo de un año

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    ObjetivoConocer la efectividad sobre el control lipídico del tratamiento hipolipemiante, basado en la práctica clínica habitual en atención primaria, en pacientes con hipercolesteremia manifiesta.DiseñoIntervención semiexperimental, antes-después.EmplazamientoCentro de salud urbano. Participantes: 187 pacientes dislipémicos conocidos, con colesterol total o colesterol LDL (cLDL) > 270 o 190 mg/dl, respectivamente.IntervenciónPráctica clínica habitual durante 12 meses en 9 consultas de atención primaria.Mediciones principalesSe registró el perfil lipídico y el tratamiento hipolipemiante al inicio del estudio y al cabo de 12 meses. El control lipídico (en función del cLDL) se evaluó como óptimo, aceptable y deficiente en función del riesgo cardiovascular según los criterios de la Sociedad Española de Arteriosclerosis (1994).ResultadosEn un 27% de casos no se registró ninguna visita relacionada con la hipercolesteremia por su médico. El número de pacientes tratados con hipolipemiantes creció de 50 a 98 (27 frente a 52%; p < 0,005), fundamentalmente a expensas del uso de estatinas. Tras 12 meses, se observaron descensos significativos en la concentración plasmática del cLDL (12%; IC del 95%, 9–15%) y del porcentaje de pacientes con control deficiente, que descendió del 91% inicial al 61% (p < 0,005), aunque sólo un 16% alcanzó un control óptimo.ConclusionesTras un año, con las condiciones de práctica clínica habitual, se observó un incremento en el uso de hipolipemiantes y una mejoría en el control lipídico, aunque algo más de la mitad de los pacientes (61%) con hipercolesteremia manifiesta permanecen con concentraciones tributarias de tratamiento.ObjectiveTo find the effectiveness of lipid-lowering treatment, based on normal clinical practice in primary care, on lipid control of patients with clear hypercholesterolaemia (HC).DesignSemi-experimental before-and-after intervention study.SettingUrban health centre. Participants: 187 patients known to have lipaemia, with total or LDL cCholesterol (cLDL) above 270 and 190 mg/dl, respectivelyInterventionNormal clinical practice for twelve months in nine primary care clinicsMain measurementsThe lipid profile and lipid-lowering treatment were recorded at the start of the study and after twelve months. Lipid control (as a function of cLDL) was evaluated as optimal, acceptable or deficient, as a function of the cardiovascular risk, following the criteria of the Spanish Arteriosclerosis Society (1994)ResultsIn 27% of cases, no visit relating to HC was recorded by the patient´s doctor. The number of patients treated with lipid-lowering drugs grew from 50 to 98 (27 vs 52%, p < 0,005), fundamentally at the expense of statin treatment. After twelve months, there were significant drops in the plasma concentration of cLDL (12%, 95%CI, 9 to 15%) and in the percentage of patients with deficient control, which fell from the initial 91% to 61% (p < 0.005), although only 16% reached optimal control.ConclusionsAfter a year, under conditions of normal clinical practice, there was an increase in the use of lipid-lowering drugs and improvement in lipid control, though a bit over half the patients (61%) with clear hypercholesterolaemia maintained concentrations requiring treatment

    Characterization of the Poly-T Variant in the TOMM40 Gene in Diverse Populations

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    We previously discovered that a polymorphic, deoxythymidine-homopolymer (poly-T, rs10524523) in intron 6 of the TOMM40 gene is associated with age-of-onset of Alzheimer's disease and with cognitive performance in elderly. Three allele groups were defined for rs10524523, hereafter ‘523’, based on the number of ‘T’-residues: ‘Short’ (S, T≤19), ‘Long’ (L, 20≤T≤29) and ‘Very Long’ (VL, T≥30). Homopolymers, particularly long homopolymers like ‘523’, are difficult to genotype because ‘slippage’ occurs during PCR-amplification. We initially genotyped this locus by PCR-amplification followed by Sanger-sequencing. However, we recognized the need to develop a higher-throughput genotyping method that is also accurate and reliable. Here we describe a new ‘523’ genotyping assay that is simple and inexpensive to perform in a standard molecular genetics laboratory. The assay is based on the detection of differences in PCR-fragment length using capillary electrophoresis. We discuss technical problems, solutions, and the steps taken for validation. We employed the novel assay to investigate the ‘523’ allele frequencies in different ethnicities. Whites and Hispanics have similar frequencies of S/L/VL alleles (0.45/0.11/0.44 and 0.43/0.09/0.48, respectively). In African-Americans, the frequency of the L-allele (0.10) is similar to Whites and Hispanics; however, the S-allele is more prevalent (0.65) and the VL-allele is concomitantly less frequent (0.25). The allele frequencies determined using the new methodology are compared to previous reports for Ghanaian, Japanese, Korean and Han Chinese cohorts. Finally, we studied the linkage pattern between TOMM40-‘523’ and APOE alleles. In Whites and Hispanics, consistent with previous reports, the L is primarily linked to ε4, while the majority of the VL and S are linked to ε3. Interestingly, in African-Americans, Ghanaians and Japanese, there is an increased frequency of the ‘523’S-APOEε4 haplotype. These data may be used as references for ‘523’ allele and ‘523’-APOE haplotype frequencies in diverse populations for the design of research studies and clinical trials

    Low-Cost Safe Water for the World: A Practical Interim Solution

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    A very large segment of the world's population is without a microbiologically safe water supply. It is estimated that in Latin America more than 40% of the population is utilizing water of dubious quality for human consumption. This figure is probably even higher in Africa and areas of southeast Asia. Water used for drinking and food preparation can be an important route of transmission for many of the most widespread and debilitating of the diseases that afflict humans. The cholera pandemic which struck Latin America in January 1991, and has become endemic in many of the countries, continues to exemplify the public health significance of contaminated drinking water. Ideally, this neglected segment of the world's population should be served with piped water systems that provide a continuous supply of microbiologically safe water, but this would require such enormous investments of financial and human resources that it is not reasonable to expect that it will be accomplished. Interim practical measures to assure microbio-logically safe water are necessary. The public health intervention to accomplish this is described in this paper and has an annual per family cost of which ranges between 1.50and1.50 and 4. It consists of providing individual households with one or preferably two suitable water containers in which to disinfect and store the essential quantities of water that need to be free of pathogens, with the containers of a design that will preclude recontamination of the contents and enable the production and distribution of the water disinfectants to be managed at the local level. It includes the necessary component of public education, promotion and involvement to establish the sustainability of the measures as a community-based endeavor. Investigation and demonstration projects are being carried out in 11 countries to determine and perfect and appropriate intervention, and it has been proven that it is economically, technically and socially feasible to assure microbiologically safe water for the world's population that is threatened by waterborne diseases. Carefully controlled microbiological analysis of the untreated and treated water shows that waterborne pathogens can be destroyed or inactivated, and carefully controlled epidemiological studies being carried out by the Centers for Disease Control and Prevention show that this intervention achieves considerable reduction in the incidence of waterborne disease. It is recommended that all developing countries initiate programs to replicate the health measure described in this paper in order to test its validity and to adapt it to their local conditions
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