Noncommutative QED and the Lifetimes of Ortho and Para Positronium

We examine the implications of including corrections associated with the noncommutative extension of quantum electrodynamics - NCQED - to the decays of the ortho and para positronium (\Trip and \Sing) ground states. In NCQED, the well known charge conjugation argument restricting \Trip decays to an odd number of photons and \Sing decays to an even number of photons no longer obtains. Instead, the dominant two photon decay mode of \Sing is accompanied by a three photon mode. The dominant three photon decay mode of \Trip receives a NCQED correction, but there is no corresponding two photon decay mode in the weak binding limit. These corrections to the $P_s$ three photon decay mode have a different energy distribution, but their effect is too small to explain any discrepancy between the observed and calculated values of the \Trip lifetime.Comment: Additional reference

Noncommutative QCD corrections to the gluonic decays of heavy quarkonia

We compute the Noncommutative QCD (NCQCD) contributions to the three gluon decay modes of heavy quarkonia. For triplet quarkonia (ortho-quarkonia), the NCQCD correction to the QCD three gluon decay mode, like the standard model contribution, is infrared finite. In the case of singlet quarkonia (para-quarkonia), whose QCD three gluon decay mode has infrared singularities which are removed using one-loop corrections to the two gluon mode, we find that NCQCD contribution is also infrared finite. The calculations are performed in the weak binding limit and do not require the introduction of additional effective couplings.Comment: Version accepted for publicatio

High energy photon-neutrino elastic scattering

The one-loop helicity amplitudes for the elastic scattering process $\gamma\nu\to\gamma\nu$ in the Standard Model are computed at high center of mass energies. A general decomposition of the amplitudes is utilized to investigate the validity of some of the key features of our results. In the center of mass, where $\sqrt{s} = 2\omega$, the cross section grows roughly as $\omega^6$ to near the threshold for $W$-boson production, $\sqrt{s} = m_W$. Although suppressed at low energies, we find that the elastic cross section exceeds the cross section for $\gamma\nu\to\gamma\gamma\nu$ when $\sqrt{s}>13$ GeV. We demonstrate that the scattered photons are circularly polarized and the net value of the polarization is non-zero. Astrophysical implications of high energy photon-neutrino scattering are discussed.Comment: 9 pages, 7 figures, RevTeX

Estratigrafía de las unidades paleozoicas aflorantes en los alrededores del arroyo Chenque Malal, ladera occidental de la Cordillera del Viento, Provincia del Neuquén

En el tramo inferior de la quebrada del arroyo Chenque Malal, sobre el flanco sudoccidental de la Cordillera del Viento en el noroeste neuquino, se identificaron y analizaron unidades carboníferas correspondientes al Grupo Andacollo y unidades pérmicas del Complejo Volcánico-Plutónico Huingancó. Las unidades aflorantes asignadas al Grupo Andacollo son las formaciones Arroyo del Torreón y Huaraco de edad carbonífera temprana y tardía respectivamente. La Formación Arroyo del Torreón está compuesta en el área por una intercalación de ortoconglomerados cuarcíticos, ignimbritas latíticas-andesíticas, delgadas capas de grauvacas líticas de origen marino, pelitas con clivaje y tobas lapillíticas cristalinas dacíticas y riolíticas. Esta unidad es cubierta en discordancia angular (D₁) por La Formación Huaraco que se compone principalmente por sedimentitas, que van desde lentes conglomerádicos y arcilitas bandeadas y deformadas en la base, a limolitas y cuarzograuvacas granoestratocrecientes. La unidad contiene fragmentos de braquiópodos (Orbiculoidea sp.), bivalvos (Palaeoneilo sp.) y de plantas fósiles, probablemente correspondientes a registro de equisetales (Cordaites y Calamites) además de un molde de semilla, lo que confirma un ambiente marino próximo a la costa para la unidad. La Formación La Premia se caracteriza por contener brechas sedimentarias depositadas mediante la discordancia sanrafaélica (D₂) sobre la Formación Huaraco y brechas piroclásticas sobre la Formación Arroyo del Torreón. Los intrusivos, menos expuestos, se asocian a cuerpos menores (diques, filones capas) vinculados al Granito Huingancó. El análisis litológico, petrográfico, estratigráfico y estructural del área permitió relevar al detalle las unidades paleozoicas redeterminando sus afloramientos y límites estratigráficos. El análisis estructural evidencia una deformación compleja desarrollada en distintos periodos e involucrando distintas cinemáticas. En el Carbonífero temprano, el diastrofismo de la Formación Arroyo del Torreón se ve reflejado en las pelitas con clivaje y en la discordancia angular que la separa de la Formación Huaraco. Durante el Pérmico basal, la fase orogénica sanrafaélica afectó al Grupo Andacollo y generó la discordancia sanrafaélica (D₂). Posteriormente, a finales del Pérmico temprano, el Grupo Andacollo es afectado por un sistema de fallas normales con componente de rumbo asignado al colapso orogénico postectónico y emplazamiento de intrusivos. Todas las estructuras mencionadas están relacionadas en el área a las distintas fases de deformación gondwánicas. Las fallas transcurrentes que afectan en el área a la Formación La Premia, son probablemente resultado de la deformación andina. De comprobarse el hallazgo de equisetales y semillas fósiles en la Formación Huaraco, éstos constituirían los primeros registros de los grupos en el Fil:área.Fil: Devoto, Luis Alberto. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina

Targeting neurosteroid synthesis as a therapy for schizophrenia-related alterations induced by early psychosocial stress

Background Cogent evidence has shown that schizophrenia vulnerability is enhanced by psychosocial stress in adolescence, yet the underpinnings of this phenomenon remain elusive. One of the animal models that best capture the relationship between juvenile stress and schizophrenia is isolation rearing (IR). This manipulation, which consists in subjecting rats to social isolation from weaning through adulthood, results in neurobehavioral alterations akin to those observed in schizophrenia patients. In particular, IR-subjected rats display a marked reduction of the prepulse inhibition (PPI) of the startle reflex, which are posited to reflect imbalances in dopamine neurotransmission in the nucleus accumbens (NAcc). We recently documented that the key neurosteroidogenic enzyme 5α-reductase (5αR) plays an important role in the dopaminergic regulation of PPI; given that IR leads to a marked down-regulation of this enzyme in the NAcc, the present study was designed to further elucidate the functional role of 5αR in the regulation of PPI of IR-subjected rats. Methods We studied the impact of the prototypical 5αR inhibitor finasteride (FIN) on the PPI deficits and NAcc steroid profile of IR-subjected male rats, in comparison with socially reared (SR) controls. Results FIN (25–100 mg/kg, i.p.) dose-dependently countered IR-induced PPI reduction, without affecting gating integrity in SR rats. The NAcc and striatum of IR-subjected rats displayed several changes in neuroactive steroid profile, including a reduction in pregnenolone in both SR and IR-subjected groups, as well as a decrease in allopregnanolone content in the latter group; both effects were significantly opposed by FIN. Conclusions These results show that 5αR inhibition counters the PPI deficits induced by IR, possibly through limbic changes in pregnenolone and/or allopregnanolone concentrations

Pharmacokinetics and endometrial tissue levels of levonorgestrel after administration of a single 1.5-mg dose by the oral and vaginal route

Objective: To determine the pharmacokinetics and endometrial tissue levels of levonorgestrel when taken as a single dose of 1.5 mg either orally or vaginally by healthy women in the periovulatory phase of their menstrual cycle. Design: Prospective randomized study. Setting: Academic research institution. Patient(s): Thirty women with regular cycles allocated to control (n = 5), oral (n 13), and vaginal (n 12) groups. Intervention(S): Blood samples were drawn before (0 time) and at 0.5, 1, 2, 4, 6, 8, 24, 48, and 168 hours after levonorgestrel administration. Endometrial samples were collected 24 and 168 hours after levonorgestrel administration. Main Outcome Measure(s): Plasma and endometrial tissue levels of levonorgestrel. Result(s): Plasma concentrations of levonorgewel were significantly greater during the first 48 hours after oral administration. However, 7 days after levonorgestrel administration, the plasma levels were similar for both treatments (3-5 nrnol/L). Compared with vaginal administration, oral administration resulted in higher peak plasma concentrations (C-max 64 vs. 10.7 nmol/L), with a shorter time to reach the maximal concentrations (T-max 1.4 vs. 6.6 hours) and with a greater AUC (509 vs. 1,75 nmol/L). Interestingly, the half-life of levonorgestrel was shorter after oral administration (25 hours vs. 32.6 hours). Levonorgestrel tissue concentrations were not related to the plasma levels. Levonorgestrel values tended to be higher in endometrial tissue after vaginal administration. The ratio between plasma and endometrial concentrations of levonorgestrel differed significantly between the groups. Conclusion(s): These data indicate that orally administered levonorgestrel achieves higher plasma levels sooner I than vaginally administered levonorgestrel. However, plasma levels after vaginal administration are more sustained and were likely to be sufficient for ovarian suppression. Therefore, the vaginally administered levonorgestrel could be considered as an alternative option for emergency contraception

The steroidogenic response and corpus luteum expression of the steroidogenic acute regulatory protein after human chorionic gonadotropin administration at different times in the human luteal phase

This study was designed 1) to assess corpus luteum (CL) steroidogenesis in response to exogenous human chorionic gonadotropin (hCG) at different times during the luteal phase, 2) to examine the effect of hCG on steroidogenic acute regulatory protein (STAR) expression within the CL, 3) to correlate StAR expression and luteal steroidogenic responses to hCG, and 4) to determine whether endogenous LH regulates ovarian steroidogenesis in the early luteal phase. Blood was collected before and after hCG treatment for steroid and hCGβ determinations. CL were obtained at the time of surgery to assess StAR gene and protein expression. During the early luteal phase various women received the GnRH antagonist for 24-48 h; some of them also received hCG 24 h after the GnRH antagonist. A slight steroidogenic response to hCG was observed in early luteal phase; 17α-hydroxyprogesterone, but not progesterone (P4), levels were significantly increased 8 h post-hCG, indicating a differential response by th

Are We Done with MMLU?

Maybe not. We identify and analyse errors in the popular Massive Multitask Language Understanding (MMLU) benchmark. Even though MMLU is widely adopted, our analysis demonstrates numerous ground truth errors that obscure the true capabilities of LLMs. For example, we find that 57% of the analysed questions in the Virology subset contain errors. To address this issue, we introduce a comprehensive framework for identifying dataset errors using a novel error taxonomy. Then, we create MMLU-Redux, which is a subset of 3,000 manually re-annotated questions across 30 MMLU subjects. Using MMLU-Redux, we demonstrate significant discrepancies with the model performance metrics that were originally reported. Our results strongly advocate for revising MMLU's error-ridden questions to enhance its future utility and reliability as a benchmark. Therefore, we open up MMLU-Redux for additional annotation https://huggingface.co/datasets/edinburgh-dawg/mmlu-redux

La hora del museo: la sala Uriburu del Museo Histórico y Colonial de la Provincia de Buenos Aires (Luján, 1932)

El artículo analiza el proceso de creación de la Sala Uriburu del Museo Histórico y Colonial de la Provincia de Buenos Aires instalado en la ciudad de Luján y abierto al público en 1923. La sala fue inaugurada el 4 de septiembre de 1932 y estaba destinada a honrar la memoria del líder de la "Revolución" del 6 de septiembre de 1930. El objetivo es dar cuenta de los múltiples factores que incidieron en su instalación considerando que ella no puede explicarse solamente a través de la relación directa entre coyuntura política, atmósfera nacionalista y la necesidad de crear un mito para perpetuar su memoria. Proponemos entonces explorar las prácticas y dispositivos colectivos indispensables en el proceso de creación de evidencias materiales para sustentar la visualización de un relato histórico.O artigo analisa o processo de instalação da Sala Uriburu, do Museu Histórico e Colonial da Província de Buenos Aires, fundado na cidade de Luján e aberto ao público em 1923. A sala foi inaugurada em 4 de setembro de 1932, e destinava-se a "honrar a memória" do líder da "Revolução" de 6 de setembro de 1930, poucos meses depois de sua morte. O objetivo é dar conta dos múltiplos fatores que incidiram na instalação, considerando que ela não pode ser explicada somente através da relação direta entre conjuntura política, atmosfera nacionalista e a necessidade de criar um mito para perpetuar sua memória. Propomos, então, explorar as práticas e dispositivos coletivos indispensáveis no processo de criação de evidências materiais para sustentar a visualização de um relato histórico.This article analyzes the installation of Uriburu's Hall at the Museo Histórico y Colonial de la Provincia de Buenos Aires, institution established in Luján in 1923. This hall was opened to the public in September 1932, to celebrate the name and memory of the hero of the Revolution of 1930. Far from proposing a direct relationship between politics and museum displays, this article wants to display the several elements that colluded in the creation of this hall