Search for Dark-Matter-Nucleon Interactions via Migdal Effect with DarkSide-50.

Dark matter elastic scattering off nuclei can result in the excitation and ionization of the recoiling atom through the so-called Migdal effect. The energy deposition from the ionization electron adds to the energy deposited by the recoiling nuclear system and allows for the detection of interactions of sub-GeV/c^{2} mass dark matter. We present new constraints for sub-GeV/c^{2} dark matter using the dual-phase liquid argon time projection chamber of the DarkSide-50 experiment with an exposure of (12 306±184) kg d. The analysis is based on the ionization signal alone and significantly enhances the sensitivity of DarkSide-50, enabling sensitivity to dark matter with masses down to 40 MeV/c^{2}. Furthermore, it sets the most stringent upper limit on the spin independent dark matter nucleon cross section for masses below 3.6 GeV/c^{2}.

Search for Dark Matter Particle Interactions with Electron Final States with DarkSide-50.

We present a search for dark matter particles with sub-GeV/c^{2} masses whose interactions have final state electrons using the DarkSide-50 experiment's (12 306±184) kg d low-radioactivity liquid argon exposure. By analyzing the ionization signals, we exclude new parameter space for the dark matter-electron cross section σ[over ¯]_{e}, the axioelectric coupling constant g_{Ae}, and the dark photon kinetic mixing parameter κ. We also set the first dark matter direct-detection constraints on the mixing angle |U_{e4}|^{2} for keV/c^{2} sterile neutrinos.

Constraints on Sub-GeV Dark-Matter-Electron Scattering from the DarkSide-50 Experiment.

We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target. The detector has a very high trigger probability for these signals, allowing for an analysis threshold of three extracted electrons, or approximately 0.05 keVee. We calculate the expected recoil spectra for dark matter-electron scattering in argon and, under the assumption of momentum-independent scattering, improve upon existing limits from XENON10 for dark-matter particles with masses between 30 and 100 MeV/c^{2}.

Low-Mass Dark Matter Search with the DarkSide-50 Experiment.

We present the results of a search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 20 GeV/c^{2} using a target of low-radioactivity argon with a 6786.0 kg d exposure. The data were obtained using the DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso. The analysis is based on the ionization signal, for which the DarkSide-50 time projection chamber is fully efficient at 0.1 keVee. The observed rate in the detector at 0.5 keVee is about 1.5 event/keVee/kg/d and is almost entirely accounted for by known background sources. We obtain a 90% C.L. exclusion limit above 1.8 GeV/c^{2} for the spin-independent cross section of dark matter WIMPs on nucleons, extending the exclusion region for dark matter below previous limits in the range 1.8-6 GeV/c^{2}.

Factors affecting the incidence of early endoscopic recurrence after ileocolonic resection for Crohn's disease: a multicentre observational study.

AIM: Early endoscopic recurrence is frequently observed in patients following resection for Crohn's disease (CD). However, factors affecting the incidence of an early postoperative endoscopic recurrence (EPER) have not been fully determined. The aim of this study was to evaluate risk factors for EPER after ileocolonic resection for CD. METHOD: This was a retrospective, international multicentre study, in which 127 patients with a first ileocolonoscopy conducted between 6 and 12 months after ileocolonic resection for CD were included. Endoscopic recurrence was defined as a Rutgeerts score of ≥ i2. The following variables were investigated as potential risk factors for EPER: gender, age at surgery, location and behaviour of CD, smoking, concomitant perianal lesions, preoperative use of steroids, immunomodulators and biologics, previous resection, blood transfusion, surgical procedure (open vs laparoscopic approach), length of resected bowel, type of anastomosis (side-to-side vs end-to-end), postoperative complications, granuloma and postoperative biological therapy. Variables related to the patient, disease and surgical procedure were investigated as potential risk factors for EPER, with univariate and multivariate (logistic regression) analyses. RESULTS: 43/127 (34%) patients had EPER at the time of the first postoperative ileocolonoscopy. In univariate analysis, only preoperative steroid use was significantly associated with a higher rate of EPER [21/45 patients (47%) on steroids and 22/82 patients (27%) without steroids (P = 0.04)]. In multivariate analysis, only preoperative steroid use was a significant independent risk factor for EPER (odds ratio 3.28, 95% confidence interval: 1.30-8.28; P = 0.01). CONCLUSIONS: This study found that only preoperative steroid use was a significant risk factor for EPER after ileocolonic resection for CD. Prospective studies are necessary to evaluate precisely the impact of perioperative medications on EPER rates.

Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory.

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy.

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory.

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.

Measurement of the proton-air cross section at √s=57 TeV with the Pierre Auger Observatory.

We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)(-36)(+28)(syst)] mb is found.

Markers of metabolic syndrome in obese children before and after 1-year lifestyle intervention program.

PURPOSE: Excess weight may be related to the development of adverse cardiometabolic risk factors in children. The aim of this study was to evaluate the effect of a lifestyle intervention program (nutrition and exercise counseling) on anthropometric parameters and metabolic syndrome (MS) components in Portuguese overweight/obese children. METHODS: A total of 83 overweight/obese children aged 7-9 years were assigned to a 1-year individual or group-based treatment (GT); 61 children (z-score BMI (zBMI): 1.93 ± 0.28; 27 boys and 34 girls) completed the program. Anthropometric and biochemical parameters were assessed at baseline, at 6 months and at 1 year. RESULTS: The overweight/obese children, compared to normal-weight ones, presented significantly higher blood pressure, total-cholesterol, total-cholesterol/high density lipoprotein cholesterol (HDL) ratio, triglycerides, Apolipoprotein B and C-reactive protein levels, while HDL and Apolipoprotein A-I were significantly lower. At baseline, the prevalence of MS was 16.4% in overweight/obese and 0% in normal-weight children. The number of components of MS was significantly higher in children with higher zBMI. Lifestyle intervention led to a significant improvement in zBMI, waist circumference/height ratio, HDL, triglycerides, Apolipoprotein A-I, and Apolipoprotein B levels. The prevalence of MS decreased to 14.8%. The GT intervention seems to be more successful, with a significant decrease in zBMI and an increase in HDL and a lower drop-out rate. CONCLUSIONS: Overweight/obese children have multiple risk factors associated with the MS. Lifestyle intervention, both individual and group-based treatment, led to an improvement in the degree of overweight/obesity and in MS components.

Snakebites in Paraiba, Brazil

The epidemiological data on snakebites in the state of Paraíba, Brazil, is scarce. This accounts for the difficulties in helping the victims. Hence, to obtain the clinical and epidemic profile of the snakebite accidents in Paraíba, we studied the number of cases recorded in this state between January 1995 and December 2000. The data was collected from these sources: Center for Toxicological Assistance (Centro de Assistência Toxicológica – CEATOX) and State Secretariat of Health (Secretaria Estadual de Saude), João Pessoa; 3rd Regional Health Center (3. Núcleo Regional de Saúde - NRS) and the Division of Epidemiological Vigilance of the Municipal Secretariat of Health (Divisão de Vigilância Epidemiológica da Secretaria Municipal de Saúde - DVE/SMS), Campina Grande. The annual distribution of the snakebite incidence showed an irregularity and an increase in March, May and August; followed by a large reduction in November and December. It was also observed that snakebites occurred more frequently in the rural area, mainly among the male laborers between 10-49 years. In most cases, the bite occurred on the leg or foot. The interval between the snakebite and the medical assistance was less than six hours. The most common symptoms were pain, edema, erythema, and bleeding. The low lethality index and the high frequency of healing, without sequels, suggest that the treatment with serum neutralized the poison, indicating the efficacy of this treatment against snakebites by the specific species found in this region

Heterofucans from Dictyota menstrualis have anticoagulant activity.

Fucan is a term used to denote a family of sulfated L-fucose-rich polysaccharides which are present in the extracellular matrix of brown seaweed and in the egg jelly coat of sea urchins. Plant fucans have several biological activities, including anticoagulant and antithrombotic, related to the structural and chemical composition of polysaccharides. We have extracted sulfated polysaccharides from the brown seaweed Dictyota menstrualis by proteolytic digestion, followed by separation into 5 fractions by sequential acetone precipitation. Gel electrophoresis using 0.05 M 1,3-diaminopropane-acetate buffer, pH 9.0, stained with 0.1% toluidine blue, showed the presence of sulfated polysaccharides in all fractions. The chemical analyses demonstrated that all fractions are composed mainly of fucose, xylose, galactose, uronic acid, and sulfate. The anticoagulant activity of these heterofucans was determined by activated partial thromboplastin time (APTT) using citrate normal human plasma. Only the fucans F1.0v and F1.5v showed anticoagulant activity. To prolong the coagulation time to double the baseline value in the APTT, the required concentration of fucan F1.0v (20 g/ml) was only 4.88-fold higher than that of the low molecular weight heparin Clexane (4.1 g/ml), whereas 80 g/ml fucan 1.5 was needed to obtain the same effect. For both fucans this effect was abolished by desulfation. These polymers are composed of fucose, xylose, uronic acid, galactose, and sulfate at molar ratios of 1.0:0.8:0.7:0.8:0.4 and 1.0:0.3:0.4:1.5:1.3, respectively. This is the fist report indicating the presence of a heterofucan with higher anticoagulant activity from brown seaweed.

Heterofucans from Dictyota menstrualis have anticoagulant activity

Fucan is a term used to denote a family of sulfated L-fucose-rich polysaccharides which are present in the extracellular matrix of brown seaweed and in the egg jelly coat of sea urchins. Plant fucans have several biological activities, including anticoagulant and antithrombotic, related to the structural and chemical composition of polysaccharides. We have extracted sulfated polysaccharides from the brown seaweed Dictyota menstrualis by proteolytic digestion, followed by separation into 5 fractions by sequential acetone precipitation. Gel electrophoresis using 0.05 M 1,3-diaminopropane-acetate buffer, pH 9.0, stained with 0.1 percent toluidine blue, showed the presence of sulfated polysaccharides in all fractions. The chemical analyses demonstrated that all fractions are composed mainly of fucose, xylose, galactose, uronic acid, and sulfate. The anticoagulant activity of these heterofucans was determined by activated partial thromboplastin time (APTT) using citrate normal human plasma. Only the fucans F1.0v and F1.5v showed anticoagulant activity. To prolong the coagulation time to double the baseline value in the APTT, the required concentration of fucan F1.0v (20 æg/ml) was only 4.88-fold higher than that of the low molecular weight heparin Clexane® (4.1 æg/ml), whereas 80 æg/ml fucan 1.5 was needed to obtain the same effect. For both fucans this effect was abolished by desulfation. These polymers are composed of fucose, xylose, uronic acid, galactose, and sulfate at molar ratios of 1.0:0.8:0.7:0.8:0.4 and 1.0:0.3:0.4:1.5:1.3, respectively. This is the fist report indicating the presence of a heterofucan with higher anticoagulant activity from brown seaweed.

Search for the decay KL --> pi(0)e+e-.

We report on a search for the decay KL-->pi(0)e+e- carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the Cabibbo-Kobayashi-Maskawa mechanism for CP violation or could point to new physics. Two events were observed in the 1997 data with an expected background of 1.06+/-0.41 events, and we set an upper limit B(KL-->pi(0)e+e-)<5.1 x 10(-10) at the 90% confidence level.

[Serologic diagnosis of several infectious diseases]. / Diagnóstico serológico de algumas doenças infecciosas.

Serological tests are, in some situations, the only method of diagnosis of some infectious diseases. The authors make a review of the literature about the most important tests used in the most common infectious diseases and also their interpretation. It is important to point out that serology should not be considered alone but compared to clinical manifestations presented by the patient. It is also necessary, in some cases, to obtain two samples of serum, to confirm if there is an increase in the antibodies' titles. The results sent from the laboratory should be interpreted based on references given by it.

Serotypes and antibiotic sensitivity of Moraxella bovis isolated from an outbreak of infectious bovine keratoconjunctivitis.

Samples of conjunctival fluid of four calves, from a herd with infectious bovine keratoconjunctivitis, were collected five times at monthly intervals and from another 16 calves in the initial stages of the disease, were collected only once. Moraxella bovis was recovered from 82.3% of the samples. Twenty-six isolates were typed with polyvalent sera and 25 with monovalent sera. The antibiotic sensitivity of 13 isolates was also studied. Twenty of the 26 isolates reacted with polyvalent sera and 16 of 25 tested isolates, reacted with monovalent sera. The isolates recovered from the same animal in a different collection or from a different animal in the same collection did not always belong to the same serogroup. Different serotypes were prevalent in each collection. Differences in the antibiotic sensitivity of the isolates were also detected.

[Antimicrobial substances of superior plants. 45. Primary observations of 2 new quinoids isolated from Hyptis fructicosa Salzm ex Benth(Labiatae)]. / Substáncias antimicrobianas de plantas superiores. Communicação XLV. Primeiras observações sobre dois novos quinonoides isolados de Hyptis fructicosa Salzm ex Benth. (Labiatae)

The authors present the first observations on the isolation of two quinonoid compounds from Hyptis fructicosa Salzm ex Benth; Labiatae. The referred naturally compounds present antimicrobial and antineoplastic activity against Gram-positive microrganisms and mouse Erlich carcionama, respectivelly.