How rapidly do neutron stars spin at birth? Constaints from archival X-ray observations of extragalactic supernovae

Traditionally, studies aimed at inferring the distribution of birth periods of neutron stars are based on radio surveys. Here we propose an independent method to constrain the pulsar spin periods at birth based on their X-ray luminosities. In particular, the observed luminosity distribution of supernovae (SNe) poses a constraint on the initial rotational energy of the embedded pulsars, via the correlation found for radio pulsars, and under the assumption that this relation continues to hold beyond the observed range. We have extracted X-ray luminosities (or limits) for a large sample of historical SNe observed with Chandra, XMM and Swift, which have been firmly classified as core-collapse SNe. We have then compared these observational limits with the results of Monte Carlo simulations of the pulsar X-ray luminosity distribution for a range of values of the birth parameters. We find that a pulsar population dominated by millisecond periods at birth is ruled out by the data

Hardy's inequalities for monotone functions on partially ordered measure spaces

We characterize the weighted Hardy's inequalities for monotone functions in ${\mathbb R^n_+}.$ In dimension $n=1$, this recovers the classical theory of $B_p$ weights. For $n>1$, the result was only known for the case $p=1$. In fact, our main theorem is proved in the more general setting of partially ordered measure spaces.Comment: 14 page

Fifteen years follow-up of photorefractive keratectomy up to 10 D of myopia: outcomes and analysis of the refractive regression

PURPOSE: To evaluate outcomes of photorefractive keratectomy up to -10.00 D of myopia and -4.50 of astigmatism and to develop a predictive model for the refractive changes in the long term. SETTING: Vissum Corporation and Miguel Hernandez University (Alicante, Spain). DESIGN: Retrospective-prospective observational series of cases. METHODS: This study included 33 eyes of 33 patients aged 46.79±7.04 years (range 40-57) operated with the VISX 20/20 excimer laser with optical zones of 6 mm. No mitomycin C was used in any of these cases. The minimum follow-up was 15 years. The main outcome measures were: uncorrected and corrected distance visual acuity, manifest refraction and corneal topography. Linear regression models were developed from the observed refractive changes over time. RESULTS: Safety and efficacy indexes at 15 years were 1.18 and 0.83, respectively. No statistically significant differences were detected for any keratometric variable during the follow-up (p≥0.103). 15 years after the surgery 54.55% of the eyes were within ±1.00 D of spherical equivalent and 84.85% within ±2.00 D. The uncorrected distance visual acuity at 15 years was 20/25 or better in 60.6% of the eyes and 20/40 or better in 72.73% of the eyes. The correlation between the attempted and the achieved refractions was r=0.948 (p<0.001) at 1 year, and r=0.821 (p<0.001) at 15 years. No corneal ectasia was detected in any case during the follow-up. CONCLUSIONS: Photorefractive keratectomy is a safe refractive procedure in the long term within the range of myopia currently considered suitable for its use, although its efficacy decreases with time, especially, in high myopia. The model developed predicts a myopic regression of 2.00 D at 15 years for an ablation depth of 130 µm

The effect of upstream boundary layer conditions on planar wake development

This paper investigates the characteristics of the turbulent wake structure developing from the trailing edge of an elliptical leading edge flat plate using particle image velocimetry. The objective of this present research is to measure the velocity fields in the near and far wake regions of the flat plate to provide insight into the flow mechanisms responsible for the development of the coherent structures within the wake due to the characteristics of the boundary layer at the trailing edge. The effect of two different boundary layers at the trailing edge of the flat plate is investigated – one laminar and one turbulent. In the laminar boundary layer case, the boundary layer is allowed to develop from the elliptic leading edge without disturbance to the trailing edge feeding a laminar boundary layer into the wake. In the turbulent boundary layer case, exactly the same free-stream velocity as the laminar case is used, but the boundary layer is tripped at the leading edge such that a turbulent boundary layer at the trailing edge feeds into the wake

How agriculture, connectivity and water management can affect water quality of a Mediterranean coastal wetland

The Natural Park of Albufera (Valencia, Spain) is an important Mediterranean coastal wetland that suffers continuous environmental effects from human activities and water uses, mainly related to agriculture and urban/industrial sewage discharges. The aim of this research was to assess the water quality of the different aquatic environments of this wetland, taking into account the connection between them, the agricultural impact and the management of irrigation water. The UEWater Framework Directive was followed in order to evaluate the ecological and trophic status of water systems. Spatial approaches were used to integrate physicochemical data into GIS vector layers to map the more problematic points of pollution. The results showed a globally eutrophic system with poor ecological potential. The wetland is nutrient-overloaded during the entire rice cultivation period. Good-quality water inputs are deficient, since the river network already has high levels of nutrients and pollutants, especially in the northern area, where river water is mixed with inappropriate effluents from wastewater treatment plants. Agriculture and water management affected the area intensively up to the Albufera lake, modulating most of the studied variables. The information gathered here can help to optimize the global study and management of the coastal Mediterranean wetlands, which are highly linked to agriculture

Recovery of the Historical SN1957D in X-rays with Chandra

SN1957D, located in one of the spiral arms of M83, is one of the small number of extragalactic supernovae that has remained detectable at radio and optical wavelengths during the decades after its explosion. Here we report the first detection of SN1957D in X-rays, as part of a 729 ks observation of M83 with \chandra. The X-ray luminosity (0.3 - 8 keV) is 1.7 (+2.4,-0.3) 10**37 ergs/s. The spectrum is hard and highly self-absorbed compared to most sources in M83 and to other young supernova remnants, suggesting that the system is dominated at X-ray wavelengths by an energetic pulsar and its pulsar wind nebula. The high column density may be due to absorption within the SN ejecta. HST WFC3 images resolve the supernova remnant from the surrounding emission and the local star field. Photometry of stars around SN1957D, using WFC3 images, indicates an age of less than 10**7 years and a main sequence turnoff mass more than 17 solar masses. New spectra obtained with Gemini-South show that the optical spectrum continues to be dominated by broad [O III] emission lines, the signature of fast-moving SN ejecta. The width of the broad lines has remained about 2700 km/s (FWHM). The [O III] flux dropped precipitously between 1989 and 1991, but continued monitoring shows the flux has been almost constant since. In contrast, radio observations over the period 1990-2011 show a decline rate inf the flux proportional to t**-4, far steeper than the rate observed earlier, suggesting that the primary shock has overrun the edge of a pre-SN wind.Comment: 28 pages, including 3 tables and 7 figures, accepted for publication in Ap

A disrupted bulgeless satellite galaxy as counterpart of the ultraluminous X-ray source ESO 243-49 HLX-1

The point-like X-ray source HLX-1, close to the S0 galaxy ESO 243-49, is one the strongest intermediate-mass black hole candidates, but the nature of its counterpart is still puzzling. By means of N-body/smoothed particle hydrodynamics simulations, we investigate the hypothesis that the HLX-1 counterpart is the nucleus of a bulgeless satellite galaxy, which undergoes a minor merger with the S0galaxy.We derived synthetic surface brightness profiles for the simulated counterpart of HLX-1 in six Hubble Space Telescope (HST) filters, ranging from far ultraviolet (FUV) to infrared wavelengths, and we compared them with the observed profiles. Our model matches the emission associated with the HLX-1 counterpart in all considered filters, including the bluer ones, even without requiring the contribution of an irradiated disc. The simulation can also account for an extended FUV emission, which is hinted at by the analysis of the F140LP HST filter. This matching is impossible to achieve by assuming either a bulgy satellite, a young star cluster, or an irradiated disc component

Monitoring of patogen parasites in waste waters of agricultural industries

Las aguas residuales son potenciales portadoras de enteroparásitos patógenos para el hombre cuya dosis infectiva puede ser mínima y prolongado el tiempo de sobrevivencia de huevos y quistes en el ambiente. La reglamentación limita la presencia de huevos de helmintos y, hasta el año 2000, no proponía una técnica para su detección. Este trabajo se realizó para caracterizar parasitológicamente los efluentes procedentes de agroindustrias. La capacitación en la identificación microscópica demandó la confección de fichas que describen las características de huevos de helmintos. Se efectuaron ensayos con muestras de bodegas y aceiteras en los puntos detectados de contaminación. Los métodos fueron adaptados a las particularidades de los efluentes. Los resultados no señalaron presencia de helmintos; no obstante, se hallaron Cyclospora e Isospora, protozoarios que, por su alto poder infectivo, también constituyen un riesgo para el hombre. Sin embargo, no están contemplados por la legislación. Respecto a helmintos, es necesario un estudio comparativo de las técnicas de detección para efluentes agroindustriales, con el fin de establecer las que optimicen su recuperación. En cuanto a otras especies es preciso continuar investigando su presencia para evaluar la conveniencia de incorporarlas a la reglamentación.Wastewaters are potential human's pathogenic parasite carriers which could be infective in small quantities. Besides, the eggs and cysts survival time could be prolonged. Regulation, restricts helminths eggs presence and, until 2000, did not propose a detection technique. This research aims to the parasitological characterization of waste water from agrarian industries. Training about microscopical identification led us to write a helminths eggs characteristics description. Since the detection of pollution points, essays were made with samples from wine vault and olive oil factories. Techniques were adapted, according to wastewater peculiarities. The results did not show helminths presence, but we found Cyclospora and Isospora. They are protozoa whose high infective power makes them a human health risk. However, they are not included in current legislation. With respect to helminths, we concluded that it is important to make a detection techniques comparative study for wastewater in order to establish which one is the best for helminths recovery. Since other species identification, it is necessary to investigate their presence in order to evaluate the convenience of incorporating them to water regulation.Fil: Enriquez, Verónica L.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Biomatemática y FisicoquímicaFil: Soria, Adriana E.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Biomatemática y FisicoquímicaFil: Salomón, María C.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de Patologí