Strong disorder fixed points in the two-dimensional random-bond Ising model

The random-bond Ising model on the square lattice has several disordered critical points, depending on the probability distribution of the bonds. There are a finite-temperature multicritical point, called Nishimori point, and a zero-temperature fixed point, for both a binary distribution where the coupling constants take the values +/- J and a Gaussian disorder distribution. Inclusion of dilution in the +/- J distribution (J=0 for some bonds) gives rise to another zero-temperature fixed point which can be identified with percolation in the non-frustrated case (J >= 0). We study these fixed points using numerical (transfer matrix) methods. We determine the location, critical exponents, and central charge of the different fixed points and study the spin-spin correlation functions. Our main findings are the following: (1) We confirm that the Nishimori point is universal with respect to the type of disorder, i.e. we obtain the same central charge and critical exponents for the +/- J and Gaussian distributions of disorder. (2) The Nishimori point, the zero-temperature fixed point for the +/- J and Gaussian distributions of disorder, and the percolation point in the diluted case all belong to mutually distinct universality classes. (3) The paramagnetic phase is re-entrant below the Nishimori point, i.e. the zero-temperature fixed points are not located exactly below the Nishimori point, neither for the +/- J distribution, nor for the Gaussian distribution.Comment: final version to appear in JSTAT; minor change

Light Sneutrino Dark Matter at the LHC

In supersymmetric (SUSY) models with Dirac neutrino masses, a weak-scale trilinear A-term that is not proportional to the small neutrino Yukawa couplings can induce a sizable mixing between left and right-handed sneutrinos. The lighter sneutrino mass eigenstate can hence become the lightest SUSY particle (LSP) and a viable dark matter candidate. In particular, it can be an excellent candidate for light dark matter with mass below ~10 GeV. Such a light mixed sneutrino LSP has a dramatic effect on SUSY signatures at the LHC, as charginos decay dominantly into the light sneutrino plus a charged lepton, and neutralinos decay invisibly to a neutrino plus a sneutrino. We perform a detailed study of the LHC potential to resolve the light sneutrino dark matter scenario by means of three representative benchmark points with different gluino and squark mass hierarchies. We study in particular the determination of the LSP (sneutrino) mass from cascade decays involving charginos, using the mT2 variable. Moreover, we address measurements of additional invisible sparticles, in our case the lightest neutralino, and the question of discrimination against the MSSM.Comment: 25 pages, 16 figure

Clinical and laboratory findings in sheep experimentally poisoned by Palicourea marcgravii and the use of magnesium chloride with possible therapeutic effect on poisoning.

This study aimed to examine the efficacy of magnesium chloride therapy in sheep experimentally poisoned by Palicourea marcgravii and describe the clinical and laboratory findings that may aid in early ante mortem diagnosis of this poisoning. P. marcgravii is an important plant within a group of 22 species in Brazil that cause ?sudden death.? Its toxic component is sodium monofluoroacetate. It was observed that a time for evolution of poisoning was longer in our study compared to other studies that used the same dose of P. marcgravii in sheep. However, all animals that were poisoned and subsequently treated with magnesium chloride died. The sheep presented characteristic clinical signs before death in addition to other signs that have not been previously described for this type of poisoning, such as abdominal breathing, coughing, head pressing, and nystagmus. This is the first evaluation of hematological parameters of sheep poisoned by P. marcgravii. Leukocytosis with neutrophilia, hyperfibrinogenemia, and hyperglycemia, associated with hypophosphatemia and elevated levels of serum aspartato aminotransferase (AST), glutamate dehydrogenase (GLDH), urea, creatinine, creatine kinase (CK) and lactate dehydrogenase (LDH), were observed. Additionally, changes were noted in necropsy, such as engorged jugular, large vessel congestion, pulmonary edema. Histological examination revealed vacuolar hydropic degeneration in the distal twisted uriniferous tubules in the kidneys, similar to those reported in previous studies on P. marcgravii poisoning

Electrocardiographic, echocardiographic and heart biomarker parameters in sheep experimentally poisoned by Palicourea marcgravii (Rubiaceae).

ABSTRACT - The present study aimed to identify and describe cardiac alterations in sheep experimentally poisoned with Palicourea marcgravii through analysis of serum cardiac biomarkers (serum troponin I and creatine kinase - CK-MB) and electro and echocardiographic assessments to contribute to a better understanding of the poisoning pathophysiology. P. marcgravii is the main plant within a group of 22 species that cause sudden death in Brazil; its toxic principle is sodium monofluoroacetate. Eight healthy crossbreed male sheep, aged between five and twelve months, weighing 14 to 27kg, were evaluated. The animals received 1g kg-1 of P. marcgravii plants orally. The sheep were evaluated before administering the plant (T0) through electro and echocardiography and blood collection to assess cardiac biomarkers (CK-MB and cTnI). Collections and analyses were repeated every four hours until the animal?s death. During the study, there was the presence of extravasation of serum troponin I carried out in a qualitative test, with positive values at time T4, and the serum CK-MB biomarker had a peak at T4 and slightly decreased at T8. The electro and echocardiographic examinations showed that the cause of death in these animals was due to acute heart failure characterized by arrhythmias, tachycardia/ventricular fibrillation, drop in cardiac output, left ventricular (LV) systolic dysfunction by the progressive decrease in the LV ejection fraction (EF), decrease in LV fractional shortening (FS), and decrease in aortic flow velocity and aortic flow gradient. This study seems to be the first to evaluate cardiac alterations in sheep poisoned by P. marcgravii through cardiac biomarkers and electro and echocardiographic exams. RESUMO - O presente estudo objetivou identificar e descrever as alterações cardíacas de ovinos intoxicados experimentalmente por Palicourea marcgravii através das análises de biomarcadores cardíacos séricos (troponina I sérica e a creatinoquinase - MB) e das avaliações eletro e ecocardiográficas contribuindo para o melhor entendimento da fisiopatologia da intoxicação. Palicourea marcgravii é a principal planta dentro de um grupo de 22 espécies que causam ?morte súbita? no Brasil e seu princípio tóxico é o monofluoracetato de sódio. Foram utilizados oito ovinos saudáveis machos, sem raça definida, com idades entre cinco e doze meses e peso de 14 a 27kg. Os animais receberam 1g/kg de Palicourea marcgravii por via oral. Os ovinos foram avaliados momentos antes da administração da planta (T0) através de eletro e ecocardiograma e coleta de sangue para avaliação dos biomarcadores cardíacos (CK-MB e cTnI). As análises e coletas foram repetidas a cada quatro horas até o óbito do animal. Durante o estudo observou-se extravasamento de troponina I sérica realizada em teste qualitativo, com valores positivos já em T4, assim como o biomarcador CK-MB sérico teve seu pico de aumento em T4 e em T8 houve uma leve redução. Aos exames eletro e ecocardiográfico foi possível determinar que a causa do óbito nestes animais ocorreu devido à insuficiência cardíaca aguda caracterizada por arritmias, taquicardia/fibrilação ventricular, queda no débito cardíaco, disfunção sistólica do ventrículo esquerdo (VE) pela diminuição progressiva da fração de ejeção (EF) do VE, diminuição na fração de encurtamento (FS) do VE, diminuição da velocidade do fluxo aórtico e do gradiente do fluxo aórtico. Este é o primeiro estudo que avalia as alterações cardiológicas de ovinos intoxicados por P. marcgravii através de biomarcadores cardíacos e exames eletro e ecocardiográficos

Air pollution perception in ten countries during the COVID-19 pandemic

As largely documented in the literature, the stark restrictions enforced worldwide in 2020 to curb the COVID-19 pandemic also curtailed the production of air pollutants to some extent. This study investigates the perception of the air pollution as assessed by individuals located in ten countries: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the USA. The perceptions towards air quality were evaluated by employing an online survey administered in May 2020. Participants (N = 9394) in the ten countries expressed their opinions according to a Likert-scale response. A reduction in pollutant concentration was clearly perceived, albeit to a different extent, by all populations. The survey participants located in India and Italy perceived the largest drop in the air pollution concentration; conversely, the smallest variation was perceived among Chinese and Norwegian respondents. Among all the demographic indicators considered, only gender proved to be statistically significant

Catalase vs Peroxidase Activity of a Manganese(II) Compound: Identification of a Mn(III)-(μ-O)2-Mn(IV) Reaction Intermediate by Electrospray Ionization Mass Spectrometry and Electron Paramagnetic Resonance Spectroscopy

Herein, we report reactivity studies of the mononuclear water-soluble complex [Mn(II)(HPClNOL)(η1-NO3)(η2-NO3)] 1, where HPClNOL ) 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, toward peroxides (H2O2 and tertbutylhydroperoxide). Both the catalase (in aqueous solution) and peroxidase (in CH3CN) activities of 1 were evaluated using a range of techniques including electronic absorption spectroscopy, volumetry (kinetic studies), pH monitoring during H2O2 disproportionation, electron paramagnetic resonance (EPR), electrospray ionization mass spectrometry in the positive ion mode [ESI(+)-MS], and gas chromatography (GC). Electrochemical studies showed that 1 can be oxidized to Mn(III) and Mn(IV). The catalase-like activity of 1 was evaluated with and without pH control. The results show that the pH decreases when the reaction is performed in unbuffered media. Furthermore, the activity of 1 is greater in buffered than in unbuffered media, demonstrating that pH influences the activity of 1 toward H2O2. For the reaction of 1 with H2O2, EPR and ESI(+)-MS have led to the identification of the intermediate [Mn(III)Mn(IV)(μ- O)2(PClNOL)2]+. The peroxidase activity of 1 was also evaluated by monitoring cyclohexane oxidation, using H2O2 or tert-butylhydroperoxide as the terminal oxidants. Low yields (<7%) were obtained for H2O2, probably because it competes with 1 for the catalase-like activity. In contrast, using tert-butylhydroperoxide, up to 29% of cyclohexane conversion was obtained. A mechanistic model for the catalase activity of 1 that incorporates the observed lag phase in O2 production, the pH variation, and the formation of a Mn(III)-(μ-O)2-Mn(IV) intermediate is proposed

Randomized clinical trial to evaluate the effect of fecal microbiota transplant for initial Clostridium difficile infection in intestinal microbiome

Objective The aim of this study was to evaluate the impact of fecal donor-unrelated donor mix (FMT-FURM) transplantation as first-line therapy for C. difficile infection (CDI) in intestinal microbiome. Methods We designed an open, two-arm pilot study with oral vancomycin (250mg every 6 h for 10–14 days) or FMT-FURM as treatments for the first CDI episode in hospitalized adult patients in Hospital Universitario “Dr. Jose Eleuterio Gonzalez”. Patients were randomized by a closed envelope method in a 1: 1 ratio to either oral vancomycin or FMT-FURM. CDI resolution was considered when there was a reduction on the Bristol scale of at least 2 points, a reduction of at least 50% in the number of bowel movements, absence of fever, and resolution of abdominal pain (at least two criteria). From each patient, a fecal sample was obtained at days 0, 3, and 7 after treatment. Specimens were cultured to isolate C. difficile, and isolates were characterized by PCR. Susceptibility testing of isolates was performed using the agar dilution method. Fecal samples and FMT-FURM were analyzed by 16S rRNA sequencing. Results We included 19 patients; 10 in the vancomycin arm and 9 in the FMT-FURM arm. However, one of the patients in the vancomycin arm and two patients in the FMT-FURM arm were eliminated. Symptoms resolved in 8/9 patients (88.9%) in the vancomycin group, while symptoms resolved in 4/7 patients (57.1%) after the first FMT-FURM dose (P = 0.26) and in 5/7 patients (71.4%) after the second dose (P = 0.55). During the study, no adverse effects attributable to FMT-FURM were observed in patients. Twelve isolates were recovered, most isolates carried tcdB, tcdA, cdtA, and cdtB, with an 18-bp deletion in tcdC. All isolates were resistant to ciprofloxacin and moxifloxacin but susceptible to metronidazole, linezolid, fidaxomicin, and tetracycline. In the FMT-FURM group, the bacterial composition was dominated by Firmicutes, Bacteroidetes, and Proteobacteria at all-time points and the microbiota were remarkably stable over time. The vancomycin group showed a very different pattern of the microbial composition when comparing to the FMT-FURM group over time. Conclusion The results of this preliminary study showed that FMT-FURM for initial CDI is associated with specific bacterial communities that do not resemble the donors’ sample.Peer reviewedFinal Published versio