Correlation Function of Galaxy Groups

We use the Updated Zwicky Catalog of galaxies (Falco et al. 1999) to generate a catalog of groups, by means of a friend-of-friend algorithm. The correlation length of the total sample is well fitted with a power law $\xi(r)=(r/r_0)^\gamma$ with parameters $r_0=9.0 \pm 0.4 h^{-1}Mpc$ and $\gamma = -1.67 \pm 0.09$ for values of $r<70 h^{-1} Mpc$. Three subsamples defined by the range of group virial masses ${\cal M}$ were used to have their clustering properties examined throughout the autocorrelation function. We find an increase of the amplitude of the correlation function according to the group masses which extends the results of the $r_0-d_c$ relation for galaxy systems at small $d_c$. For completeness we have also analyzed a sample of groups obtained from the Southern Sky Redshift Survey (da Costa et al.1998) in the range of virial masses $5\times10^{12}M_{\odot}<{\cal M}<4\times10^{14}M_{\odot}$ to compare the results with those obtained from GUZC.Comment: 9 figures, accepted for publication in Ap

Effect of energy deposition modelling in coupled steady state Monte Carlo neutronics/thermal hydraulics calculations

In coupled calculations with Monte Carlo neutronics and thermal hydraulics the Monte Carlo code is used to produce a power distribution which in practice means tallying the energy deposition. Usually the energy deposition is estimated by making a simple approximation that energy is deposited only in fission reactions. The goal of this work is to study how the accuracy of energy deposition modelling affects the results of steady state coupled calculations. For this task an internal coupling between Monte Carlo transport code Serpent 2 and subchannel code SUBCHANFLOW is used along with a recently implemented energy deposition treatment of Serpent 2. The new treatment offers four energy deposition modes each of which offers a different combination of accuracy and required computational time. As a test case, a 3D PWR fuel assembly is modelled with different energy deposition modes. The resulting effective multiplication factors are within 30 pcm. Differences of up to 100K are observed in the fuel temperatures

The Role of Field-Programmable Gate Arrays in the Acceleration of Modern High-Performance Computing Workloads

Producción CientíficaReconfigurable hardware circuits, such as field-programmable gate arrays, have gained popularity in the high-performance computing (HPC) community in recent years. Nevertheless, their real contribution to accelerating HPC workloads is unclear in both potential and extent.The work of Manuel de Castro, Yuri Torres, and Diego R. Llanos has been supported in part by Grant PID2022- 142292NB-I00 (NATASHA Project), funded by MCIN/AEI/10.13059/501100011033, and by the European Regional Development Fund’s A Way of Making Europe project. Yuri Torres and Diego R. Llanos have been supported in part by Junta de Castilla y León FEDER Grant VA226P20 (PROPHET-2 Project). Diego R. Llanos has been supported in part by Grant TED2021-130367B-I00, funded by MCIN/AEI/10.13039/501100011033, and by Next Generation EU Plan de Recuperación, Transformación, y Resiliencia. The work of David L. Vilariño has been supported by Grants PID2022-141623NB-I00 and PID2019-104834GB-I00 (funded by MCIN/ AEI/10.13039/501100011033/FEDER, UE) and by the Conselleria de Cultura, Educacion, e Ordenacion Universitaria, Xunta de Galicia (Accreditation ED431C 2022/16)

Spectral evidence for jets from Accreting Millisecond X-ray Pulsars

Transient radio emission from X-ray binaries is associated with synchrotron emission from collimated jets that escape the system, and accreting millisecond X-ray pulsars (AMXPs) are no exception. Although jets from black hole X-ray binaries are well-studied, those from neutron star systems appear much fainter, for reasons yet uncertain. Jets are usually undetectable at higher frequencies because of the relative brightness of other components such as the accretion disc. AMXPs generally have small orbital separations compared with other X-ray binaries and as such their discs are relatively faint. Here, I present data that imply jets in fact dominate the radio-to-optical spectrum of outbursting AMXPs. They therefore may provide the best opportunity to study the behaviour of jets produced by accreting neutron stars, and compare them to those produced by black hole systems.Comment: 4 pages, 2 figures, to appear in the proceedings of "A Decade of Accreting Millisecond X-ray Pulsars", Amsterdam, April 2008, eds. R. Wijnands et al. (AIP Conf. Proc.

Quasar-galaxy and AGN-galaxy cross-correlations

We compute quasar-galaxy and AGN-galaxy cross-correlation functions for samples taken from the \cite{VCV98} catalog of quasars and active galaxies, using tracer galaxies taken from the Edinburgh/Durham Southern Catalog. The sample of active galaxy targets shows positive correlation at projected separations $r_p < 6 h^{-1} Mpc$ consistent with the usual power-law. On the other hand, we do not find a statistically significant positive quasar-galaxy correlation signal except in the range $3 h^{-1} Mpc < r_p < 6 h^{-1} Mpc$ where we find similar AGN-galaxy and quasar-galaxy correlation amplitudes. At separations $r_p<3 h^{-1} Mpc$ a strong decline of quasar-galaxy correlations is observed, suggesting a significant local influence of quasars in galaxy formation. In an attempt to reproduce the observed cross-correlation between quasars and galaxies, we have performed CDM cosmological hydrodynamical simulations and tested the viability of a scenario based on the model developed by \cite{silkrees98}. In this scheme a fraction of the energy released by quasars is considered to be transferred into the baryonic component of the intergalactic medium in the form of winds. The results of the simulations suggest that the shape of the observed quasar-galaxy cross-correlation function could be understood in a scenario where a substantial amount of energy is transferred to the medium at the redshift of maximum quasar activity.Comment: 11 pages, 9 figures. Accepted for publication in Ap

Implementation of a motion estimation algorithm for Intel FPGAs using OpenCL

Producción CientíficaMotion Estimation is one of the main tasks behind any video encoder. It is a compu- tationally costly task; therefore, it is usually delegated to specific or reconfigurable hardware, such as FPGAs. Over the years, multiple FPGA implementations have been developed, mainly using hardware description languages such as Verilog or VHDL. Since programming using hardware description languages is a complex task, it is desirable to use higher-level languages to develop FPGA applications.The aim of this work is to evaluate OpenCL, in terms of expressiveness, as a tool for devel- oping this kind of FPGA applications. To do so, we present and evaluate a parallel implementation of the Block Matching Motion Estimation process using OpenCL for Intel FPGAs, usable and tested on an Intel Stratix 10 FPGA. The implementa- tion efficiently processes Full HD frames completely inside the FPGA. In this work, we show the resource utilization when synthesizing the code on an Intel Stratix 10 FPGA, as well as a performance comparison with multiple CPU implementations with varying levels of optimization and vectorization capabilities. We also compare the proposed OpenCL implementation, in terms of resource utilization and perfor- mance, with estimations obtained from an equivalent VHDL implementation.Junta de Castilla y León - Consejería de Educación de la Proyecto PROPHET-2 (VA226P20)Ministerio de Economía, Industria y Competitividad: (PID2019- 104834 GB-I00) and European Regional Development Fund (ERDF) program: Project PCAS (TIN2017-88614-R)Ministerio de Ciencia e Innovación (PID2019-104184RB-I00 / AEI / 10.13039/501100011033)Xunta de Galicia y fondos FEDER de la UE (Centro de Investigación de Galicia acreditación 2019-2022, ref. ED431G 2019/01; Consolidation Program of Competitive Reference Groups, ref. ED431C 2021/30Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación y “European Union NextGenerationEU/PRTR” : (MCIN/ AEI/10.13039/501100011033) - grant TED2021-130367B-I00Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Hearing Impairment and Quality of Life in Adults with Asymmetric Hearing Loss: Benefits of Bimodal Stimulation

Objectives: Bimodal stimulation for asymmetric hearing loss is an emerging treatment with proven audiometric outcomes. Our objectives are to assess the changes of the hearing impairment and the quality of life of patients treated with this type of stimulation, when compared to a unilateral Cochlear Implant (CI) stimulated condition. Materials and methods: 31 patients with asymmetric hearing loss (Group 1) were recruited for the study. They were divided into three groups, based on their hearing loss in the ear treated with the hearing aid: Group 1A (Pure Tone Audiometry (PTA) between 41 and 70 decibels (dB)); Group 1B, (PTA between 71 and 80 dB) and Group 1C (PTA between 81 and 90 dB). 30 patients had profound, bilateral hearing loss. Then, users of a unilateral cochlear implant were recruited for the control group. Their hearing impairment and quality of life were analyzed with questionnaires Abbreviated Profile of Hearing Aid Benefit (APHAB), Speech, Spatial and Qualities of Hearing Scale (SSQ) and the Health Utilities Index (HUI). They were followed up for at least 2 years. Results: The group with the asymmetric hearing loss obtains a statistically significant clinical improvement in the APHAB under category "with hearing aid" compared to "without hearing aid". The group with the asymmetric hearing loss benefits more across basically all variables compared with the control group in the SSQ. Group 1A obtains the best outcome of the sample in the HUI. Conclusion: Bimodal stimulation and better hearing in the ear treated with the hearing aid reduce hearing impairment and improve the quality of life

Revising the western boundary of Pampa grasslands

Los mapas fitogeográficos y de eco-regiones actuales delimitan la distribución de los pastizales pampeanos argentinos a las provincias de Buenos Aires, Córdoba, Santa Fe, Entre Ríos, La Pampa y San Luis. En este trabajo revisamos su distribución en el extremo occidental por medio de muestreos a campo y análisis digitales de imágenes satelitales, e incorporamos una extensión importante de este ecosistema en las provincias de Mendoza y La Pampa. Para el mapeo satelital usamos una serie temporal de 10 años de imágenes MODIS/Terra. Realizamos una clasificación no supervisada (ISODATA), complementada con una interpretación visual sobre imágenes Landsat 8 de 2014, en dos categorías: pastizal y bosque (arbustal). La precisión total de la clasificación fue 89.1%, verificada a través de una matriz de error con imágenes de alta resolución obtenidas a partir de Google Earth. El análisis digital nos permitió identificar un área de 3050 km2 de pastizal pampeano al oeste del río Salado, en el sureste de la provincia de Mendoza y el centro-norte de La Pampa, entre 35.362° y 36.257° S, y 66.613° y 67.264° O. Los relevamientos de la vegetación en sitios representativos muestran que áreas antes categorizadas como “monte” reúnen todas las características de un típico pastizal pampeano occidental semiárido, dominando por matas perennes C4 de Elionurus muticus (paja amarga, cobertura 28%). Otras especies importantes, con coberturas que varían entre 1 y 5%, son Hyalis argentea, Sporobolus cryptandrus, Aristida mendocina, Bothriochloa springfieldii y Eragrostis lugens. La alta tasa de reemplazo que experimenta la región convierte a estos pastizales en un área de importancia ecológica para la conservación de este ecosistema frágil.The current mapping on land-cover distribution restricts the Argentinean Pampa grasslands to the Buenos Aires, Córdoba, Santa Fe, Entre Ríos, La Pampa and San Luis provinces. In this study, we reviewed the western distribution of these grasslands by using remote sensing analyses and “in situ” evaluations. We used a 10-years series of MODIS/Terra satellite images as a basis to locate and map the area of study. We also employed a non-supervised classification (ISODATA), complemented with a visual interpretation on Landsat 8 satellite images, to classify pixels into two categories: grassland and shrubland. The accuracy of this classification was 89.1%, verified through an error matrix by using high resolution images from Google Earth. We identified a new area of 3050 km2 of Pampa grasslands that was not considered in previous land-cover vegetation maps. This area, previously categorized as shrublands, is located west of the Salado river, at the south-east of Mendoza and north-center of La Pampa provinces, between 35.362° and 36.257° S, and 66.613° and 67.264° W. Vegetation surveys in specific sites showed that they are typical semiarid Pampa grasslands, dominated by C4 perennial tussocks of Elionurus muticus (28% of area cover). Other important species, with area covers between 1 and 5%, were Hyalis argentea, Sporobolus cryptandrus, Aristida mendocina, Bothriochloa springfieldii and Eragrostis lugens. The inherent low replacement rate that occurs in this semiarid region of Argentina enhances the importance of these grasslands as reservoirs of this fragile ecosystem

Phenological responses of C3 and C4 grasses to annual changes in precipitation and temperature

La temperatura y las precipitaciones son factores determinantes de la fenología y la productividad de las plantas. Alteraciones climáticas leves pueden modificar de forma significativa los ciclos de crecimiento y afectar así diferentes funciones ecosistémicas. Para evaluar las relaciones entre la fenología reproductiva de gramíneas, la temperatura y las precipitaciones, en un estudio observacional a campo se investigaron cuatro especies (dos C3 [Piptochaetium napostaense y Poa ligularis] y dos C4 [Eustachys retusa y Schizachyrium condensatum]) representativas de la Región Semiárida Central argentina. Se compararon relevamientos fenológicos llevados a cabo en dos periodos (1976-1986 y 2008-2010) sobre el mismo sitio de estudio. Para las cuatro especies, los veranos más cálidos se asociaron con ciclos reproductivos más largos. Las primaveras más cálidas se relacionaron con un adelanto en el inicio reproductivo de las C4 (pero con un retraso de las C3), los inviernos lluviosos, con un adelanto en el inicio floral de las especies C3, mientras que años con elevadas precipitaciones estivales se relacionaron con un retraso y una extensión del ciclo reproductivo de las C4. En las cuatro especies estudiadas, el inicio del ciclo reproductivo fue menos variable que el final. Esto sugiere que el inicio estaría controlado por factores externos poco variables entre años (e.g., fotoperíodo), mientras que su final podría estar regulado, en mayor medida, por factores con mayor variabilidad interanual (e.g., precipitaciones y temperaturas). El ciclo reproductivo de las dos especies C4 fue más tardío y extenso que el de las especies C3. Las relaciones encontradas en este trabajo entre clima y fenología podrían ser útiles para diseñar estrategias de manejo sustentables de estos pastizales.Temperature and precipitation are key factors in plant phenology and productivity. Modifications on growth and reproductive cycles may affect the relative fitness of the species, altering their interactions and ecosystem functions. In native grasslands of San Luis province, Argentina, C3(cold-season) and C4 (warm-season) grasses coexist, which makes these grasslands particularly interesting. In this study, we evaluated how phenology of four native grasses (two C3 and two C4) is related to changes in temperature and rainfall. We compared phenological data collected in situ during two periods: from 1976 to 1986 and from 2008 to 2010. We found that warmer summers were related with a delay on the reproductive offset and the length of the reproductive cycle in all four species. In contrast, warmer springs were related with earlier flowering of C4, but later flowering of C3 grasses. Years with rainy winters were related with earlier flowering onsets in C3 species, while rainy summers were related with later and longer reproductive cycles in C4 grasses. These results provide valuable information about vegetation responses to climate and may be used for range management purposes