Non-linear response of single-molecule magnets: field-tuned quantum-to-classical crossovers

Quantum nanomagnets can show a field dependence of the relaxation time very different from their classical counterparts, due to resonant tunneling via excited states (near the anisotropy barrier top). The relaxation time then shows minima at the resonant fields H_{n}=n D at which the levels at both sides of the barrier become degenerate (D is the anisotropy constant). We showed that in Mn12, near zero field, this yields a contribution to the nonlinear susceptibility that makes it qualitatively different from the classical curves [Phys. Rev. B 72, 224433 (2005)]. Here we extend the experimental study to finite dc fields showing how the bias can trigger the system to display those quantum nonlinear responses, near the resonant fields, while recovering an classical-like behaviour for fields between them. The analysis of the experiments is done with heuristic expressions derived from simple balance equations and calculations with a Pauli-type quantum master equation.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. B, brief report

MATISSE: an ArcGIS tool for monitoring and nowcasting meteorological hazards

Abstract. Adverse meteorological conditions are one of the major causes of accidents in aviation, resulting in substantial human and economic losses. For this reason it is crucial to monitor and early forecast high impact weather events. In this context, CIRA (Italian Aerospace Research Center) has implemented MATISSE (Meteorological AviaTIon Supporting SystEm), an ArcGIS Desktop Plug-in able to detect and forecast meteorological aviation hazards over European airports, using different sources of meteorological data (synoptic information, satellite data, numerical weather prediction models data). MATISSE presents a graphical interface allowing the user to select and visualize such meteorological conditions over an area or an airport of interest. The system also implements different tools for nowcasting of meteorological hazards and for the statistical characterization of typical adverse weather conditions for the airport selected

Serie de casos clínicos de pacientes con miopatía inflamatoria idiopática y enfermedad pulmonar intersticial del "Registro de miopatías inflamatorias idiopáticas" de la Sociedad Argentina de Reumatología

Las Miopatías Inflamatorias Idiopáticas (MII) son un grupo heterogéneo de enfermedades que se caracterizan por debilidad muscular e inflamación subyacente en la biopsia muscular. Los principales órganos afectados son el músculo, la piel y también puede afectarse el pulmón. Se distinguen dentro de los subtipos clínicos como Polimiositis (PM), Dermatomiositis (DM), DM con la variante Dermatomiositis Clínicamente Amiopática (DMCA), el Síndrome Antisintetasa (SAS), la Miositis Necrotizante Inmunomediada, la Miositis por Cuerpos de Inclusión (MCI) y la Miositis Asociada a Neoplasia. La presencia de ciertos anticuerpos específicos y asociados predispone al desarrollo de manifestaciones clínicas, determinando el pronóstico de la enfermedad. Se presentan 4 pacientes del Registro de MII de la Sociedad Argentina de Reumatología (SAR) con estas características: un paciente con PM y anti Jo-1 positivo y tres pacientes con DM (uno con DMCA y anti- RO 52 y dos pacientes con anti-PL7 y anti-TIF1γ respectivamente)

La crisis asmática: fisiopatología

El asma es una enfermedad respiratoria crónica con base inflamatoria y de etiología multifactorial, quienes la padecen tienen la vía aérea sensible a estímulos irritantes; este padecimiento es reversible espontaneamente o con tratamiento. Se considera la enfermedad crónica más frecuente en edad pediátrica, pues afecta entre 8 y 10% de los niños en naciones desarrolladas. La Organización Mundial de la Salud (OMS) estima cerca de 150 millones de personas asmáticas en el mundo, cuya mortalidad directa anual es de 2 millones de personas. Además, se calcula que cada año se presenta entre 1,5 y 2 millones de consultas por crisis asmáticas en los servicios de urgencias en los Estados Unidos, lo que genera costos directos e indirectos que rebasan 12 billones de dólares anuales, de los cuales representa el 25% la atencion directa de episodios agudos de asma, entre 20 y 30% de los pacientes con crisis asmática requiere hospitalización y hasta 20% de quienes se manejan de forma ambulatoria regresa a urgencias en las dos semanas siguientes. Debido a lo anterior, el presente artículo hace una revisión de la fisiopatología de la enfermedad como ayuda a todo médico interesado en el conocimiento del asma, reto para el siglo XXI.   Abstract Asthma is a chronic respiratory disease, with an inflammatory basis and multifactorial etiology. In these patients the airway is sensitive to multiple irritant stimuli and is reversible spontaneously or with treatment. It is considered the most common chronic disease of the pediatric age because it affects 8 to 10% of children in almost all developed nations. The World Health Organization (WHO) estimates that there are about 150 million asthmatic people in the world and that it causes an annual direct mortality of 2 million people. It is estimated that there are between 1.5 and 2 million asthmatic crisis consultations every year in the emergency services in the United States alone, which generates direct and indirect costs of over 12 billion dollars annually, of which 25% are direct attention of acute episodes of asthma. About 20% to 30% of patients who have an asthma attack require hospitalization and up to 20% of those who are operated on an outpatient basis will return to the emergency room within the next two weeks. The present work reviews the pathophysiology of the disease so that it is an aid to all doctors interested in the knowledge of this disease that represents a challenge for this 21st century

Contact-force monitoring increases accuracy of right ventricular voltage mapping avoiding “false scar” detection in patients with no evidence of structural heart disease

Purpose: Electroanatomical mapping (EAM) could increase cardiac magnetic resonance imaging (CMR) sensitivity in detecting ventricular scar. Possible bias may be scar over-estimation due to inadequate tissue contact. Aim of the study is to evaluate contact-force monitoring influence during EAM, in patients with idiopathic right ventricular arrhythmias. Methods: 20 pts (13 M; 43 ± 12 y) with idiopathic right ventricular outflow tract (RVOT) arrhythmias and no structural abnormalities were submitted to Smarttouch catheter Carto3 EAM. Native maps included points collected without considering contact-force. EAM scar was defined as area ≥1 cm2 including at least 3 adjacent points with signal amplitude (bipolar <0.5 mV, unipolar 3,5 mV), surrounded by low-voltage border zone. EAM were re-evaluated offline, removing points collected with contact force <5 g. Finally, contact force-corrected maps were compared to the native ones. Results: An EAM was created for each patient (345 ± 85 points). After removing poor contact points, a mean of 149 ± 60 points was collected. The percentage of false scar, collected during contact force blinded mapping compared to total volume, was 6.0 ± 5.2% for bipolar scar and 7.1 ± 5.9% for unipolar scar, respectively. No EAM scar was present after poor contact points removal. Right ventricular areas analysis revealed a greater number of points with contact force < 5 g acquired in free wall, where reduced mean bipolar and unipolar voltage were recorded. Conclusions: To date this is the first work conducted on structurally normal hearts in which contact-force significantly increases EAM accuracy, avoiding “false scar” related to non-adequate contact between catheter and tissue

Development of Cryogenic Current Comparators with DC Squid Readout for the Calibration of Electrical Standards

For the realization of the electrical quantum metrology triangle (V-A-Ω) a device to amplify very small currents with high precision is needed. The cryogenic current comparator (CCC) is by far the best instrument to do this. In order to make a very current sensitive CCC for calibration of electrical standards, we have developed optimum dc Superconducting QUantum Interference Devices (SQUIDs). The design, fabrication and characterisation of these devices is presented. The measurements concern the flux-to-voltage transfer and the noise properties, especially the input current noise. The optimisation of the flux transformer circuit that links the CCC with the SQUID will be treated. In addition, typical fabrication aspects of the CCC as the wires and tube assembly, the shields and the support system will be addressed

Clinical predictors of velocardiofacial syndrome as reported in patients' charts

Objective: The velocardiofacial syndrome (VCFS) involves a deletion of part of chromosome 22 and is associated to more than 180 clinical conditions. With a high variation in clinical findings, early identification of this condition may be difficulty. The objective of this study was to compare clinical findings reported in medical charts in two groups of patients with VCFS: with positive molecular testing and without testing but with clinical sigs of VPI. Methods: A list of patients with VCFS was identified in a large craniofacial center. The first 40 patients with signs of VPI that could be grouped according to presence or absence of molecular testing were included in the study. Results: The charts from 20 patients without molecular tests, 20 patients with positive molecular test for the deletion and 2 with negative molecular test were reviewed. A total of 17 health professional areas reported signs of VCFS in one or more charts, with speech pathologists reporting in all charts, clinical geneticists in 98% and pediatrician in 83% of the charts studied. A list of 31 clinical signs were reported by these professionals. Cardiac and respiratory conditions and behavioral problems were more prevalent in the group with positive molecular test. Incomplete cleft palate was reported for 43% of the patients, submucous cleft palate for 26%, congenital velopharyngeal dysfunction for 19% and other anomalies for 12%. Conclusion: Patients with VCFS that are treated in a Cleft Palate Center are biased to presenting with cleft palate or velopharyngeal dysfunction. Presence of cardiac and respiratory conditions and behavioral problems in this population can be a sign of VCFS

Enhancing Agricultural Productivity of CLMV Countries: Challenges and Agenda for Reforms

Responding positively to economic reforms, the economies of Cambodia, the Lao People's Democratic Republic, Myanmar, and Viet Nam (CLMV) have shown tremendous growth since the mid-1980s, including in their respective agriculture sectors. Recent developments, however, have brought into question the CLMV countries' ability to sustain further increases in agricultural productivity given the slow pace of reforms and emerging challenges. Going forward, the reform agenda must go beyond the traditional view of expanding yields and supply of agricultural products for development gains in the sector to contribute to inclusive growth, poverty alleviation, and food security. This will require changing the market structures and regulatory policies that govern the sector