Equation of state of a seven-dimensional hard-sphere fluid. Percus-Yevick theory and molecular dynamics simulations

Following the work of Leutheusser [Physica A 127, 667 (1984)], the solution to the Percus-Yevick equation for a seven-dimensional hard-sphere fluid is explicitly found. This allows the derivation of the equation of state for the fluid taking both the virial and the compressibility routes. An analysis of the virial coefficients and the determination of the radius of convergence of the virial series are carried out. Molecular dynamics simulations of the same system are also performed and a comparison between the simulation results for the compressibility factor and theoretical expressions for the same quantity is presented.Comment: 12 pages, 4 figures; v3: Equation (A.19) corrected (see http://dx.doi.org/10.1063/1.2390712

On the radial distribution function of a hard-sphere fluid

Two related approaches, one fairly recent [A. Trokhymchuk et al., J. Chem. Phys. 123, 024501 (2005)] and the other one introduced fifteen years ago [S. B. Yuste and A. Santos, Phys. Rev. A 43, 5418 (1991)], for the derivation of analytical forms of the radial distribution function of a fluid of hard spheres are compared. While they share similar starting philosophy, the first one involves the determination of eleven parameters while the second is a simple extension of the solution of the Percus-Yevick equation. It is found that the {second} approach has a better global accuracy and the further asset of counting already with a successful generalization to mixtures of hard spheres and other related systems.Comment: 3 pages, 1 figure; v2: slightly shortened, figure changed, to be published in JC

Detection of Anomalous Microwave Emission in the Pleiades Reflection Nebula with WMAP and the COSMOSOMAS Experiment

We present evidence for anomalous microwave emission (AME) in the Pleiades reflection nebula, using data from the seven-year release of the Wilkinson Microwave Anisotropy Probe (WMAP) and from the COSMOSOMAS experiment. The flux integrated in a 1-degree radius around R.A.=56.24^{\circ}, Dec.=23.78^{\circ} (J2000) is 2.15 +/- 0.12 Jy at 22.8 GHz, where AME is dominant. COSMOSOMAS data show no significant emission, but allow to set upper limits of 0.94 and 1.58 Jy (99.7% C.L.) respectively at 10.9 and 14.7 GHz, which are crucial to pin down the AME spectrum at these frequencies, and to discard any other emission mechanisms which could have an important contribution to the signal detected at 22.8 GHz. We estimate the expected level of free-free emission from an extinction-corrected H-alpha template, while the thermal dust emission is characterized from infrared DIRBE data and extrapolated to microwave frequencies. When we deduct the contribution from these two components at 22.8 GHz the residual flux, associated with AME, is 2.12 +/- 0.12 Jy (17.7-sigma). The spectral energy distribution from 10 to 60 GHz can be accurately fitted with a model of electric dipole emission from small spinning dust grains distributed in two separated phases of molecular and atomic gas, respectively. The dust emissivity, calculated by correlating the 22.8 GHz data with 100-micron data, is found to be 4.36+/-0.17 muK/MJy/sr, a value that is rather low compared with typical values in dust clouds. The physical properties of the Pleiades nebula indicate that this is indeed a much less opaque object than others were AME has usually been detected. This fact, together with the broad knowledge of the stellar content of this region, provides an excellent testbed for AME characterization in physical conditions different from those generally explored up to now.Comment: Accepted for publication in ApJ. 12 pages, 8 figure

Thickness of the buccal bone wall and root angulation in the maxilla and mandible: an approach to cone beam computed tomography

Background: The objective of this paper is to anatomically describe the bone morphology in the maxillary and mandibular tooth areas, which might help in planning post-extraction implants. Methods: CBCT images (Planmeca ProMax 3D) of 403 teeth (208 upper teeth and 195 lower teeth) were obtained from 49 patients referred to the Dental School of Seville from January to December 2014. The thickness of the facial wall was measured at the crest, point A, 4mm below, point B, and at the apex, point C. The second parameter was the angle formed between the dental axis and the axis of the basal bone. Results: A total of 403 teeth were measured. In the maxilla, 89.4% of incisors, 93.94% of canines, 78% of premolars and 70.5% of molars had a buccal bone wall thickness less than the ideal 2mm. In the mandible, 73.5% of incisors, 49% of canines, 64% of premolars and 53% of molars had <1mm buccal bone thickness as measured at point B. The mean angulation in the maxilla was 11.67±6.37° for incisors, 16.88±7.93° for canines, 13.93±8.6° for premolars, and 9.89±4.8° for molars. In the mandible, the mean values were 10.63±8.76° for incisors, 10.98±7.36° for canines, 10.54±5.82° for premolars and 16.19±11.22° for molars. Conclusions: The high incidence of a buccal wall thickness of less than 2mm in over 80% of the assessed sites indicates the need for additional regeneration procedures, and several locations may also require custom abutments to solve the angulation problems for screw-retained crowns

Signatures of tetraether lipids reveal anthropogenic overprinting of natural organic matter in sediments of the Thames Estuary, UK

Intertidal foreshore sediments from a 110 km stretch of the Thames Estuary were analysed for glycerol dialkyl glycerol tetraethers (GDGTs) to track soil organic matter (OM) input and evaluate the impact of coastal urbanisation on their distribution. Concentration of branched (br)GDGTs ranged from < 1 to 15 μg/g organic carbon (OC) and crenarchaeol ranged from 0.6 to 19 μg/g OC. An overall decrease in brGDGTs was observed from the inner Thames (Brentford) to the outer Thames (Isle of Grain), suggesting a drop in soil OM input towards the sea. In contrast, crenarchaeol concentration was highest around east London rather than towards the open sea. Such elevated crenarchaeol concentration occurred in the section of the river most influenced by anthropogenic pollution, such as discharge points for London’s major sewage treatment plants, docks and power plants. The non-systematic spatial distribution of crenarchaeol was also reflected in the branched isoprenoid tetraether (BIT) index. The highest BIT values occurred upstream and in close proximity to salt marshes (0.8–1), whereas the lowest values (0.3–0.5) were towards the sea. However, unusually low values (0.4) were observed in the river section that had high crenarchaeol concentration. In contrast, bulk δ13C values were insensitive to London’s anthropogenic influence. This suggests that the natural systematic decrease in BIT index in the estuary is overprinted by London’s anthropogenic activity between Deptford Creek and Tilbury. We therefore advise caution when interpreting the BIT index for sediments in close proximity to megacities discharging industrial and municipal waste that can become incorporated into the near surface sedimentary record

Molecular dynamics simulation of the regrowth of nanometric multigate Si devices

We use molecular dynamics (MD) simulation techniques to study the regrowth of nanometric multigate Si devices, such as fins and nanowires, surrounded by free surfaces and interfaces with amorphous material. Our results indicate that atoms in amorphous regions close to lateral free surfaces or interfaces rearrange at a slower rate compared to those in bulk due to the discontinuity of the lateral crystalline template. Consequently, the recrystallization front which advances faster in the device center than at the interfaces adopts new orientations. Regrowth then proceeds depending on the particular orientation of the new amorphous/crystal interfaces. In the particular case of (110) oriented fins, the new amorphous/crystal interfaces are aligned along the (111) direction, which produces frequent twining during further regrowth. Based on our simulation results, we propose alternatives to overcome this defected recrystallization in multigate structures: device orientation along (100) to prevent the formation of limiting {111} I amorphous/crystal interfaces and presence of a crystalline seed along the device body to favor regrowth perpendicular to the lateral surfaces/interfaces rather than parallel to them. (C) 2012 American Institute of Physics. [doi :10.1063/1.3679126

Preliminary Inventory of Boats and Gears in Manila Bay

Recent information about the number and types of boats and gears used in Manila Bay is lacking. Here we discuss the results of the initial boat and gear inventory conducted in Manila Bay from May 2015 to October 2016. The survey was done in the coastal barangays of Cavite, Bataan, Bulacan, Pampanga, and Metro Manila. A total of 3,659 fishing boats were recorded from 84 coastal barangays or about 40% out of the 212 coastal barangays in Manila Bay. About 94.45% of the boats are municipal fishing boats and only 5.55% are commercial boats and the highest number of boats recorded was in Cavite (1,461 boats). 91.04% of the fishing boats are motorized and only 8.96% are non-motorized. The average fisher to boat ratio for the five provinces is 3.0:1, which is higher compared to the 2.4:1 result of MADECOR and National Museum Assessment (1995). There are 25 types of fishing gears recorded during the survey with a total of4, 946 units. Gillnet, specifically bottom gillnet, is the most dominant gear being used in Manila Bay

Survey of Zoonotic Diarrheagenic Protist and Hepatitis E Virus in Wild Boar (Sus scrofa) of Portugal

Simple Summary Enteropathogenic viruses, such as hepatitis E virus, and diarrhoeagenic protists have been frequently reported in swine and can infect a wide range of mammals, including humans. Data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Of the 144 samples tested, 2 showed the presence of Cryptosporidium scrofarum, 21 Balantioides coli, 42 Blastocystis ST5, and 4 HEV genotype 3. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Enteropathogenic parasites and viruses have been frequently reported in swine and can infect a wide range of mammals, including humans. Among the wide variety of parasites infecting swine, diarrhoeagenic protists are among those that cause significant morbidity. Hepatitis E virus (HEV) has also been reported both in domestic pigs and wild boar and is known to have an important public health significance. These agents share the fecal-oral transmission route, but data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Wild boar stool samples (n = 144) were obtained during the official hunting seasons (October to February) in 2018/2019, 2019/2020, and 2021/2022 and tested for Cryptosporidium spp., Balantioides coli, Giardia duodenalis, Blastocystis sp., Enterocytozoon bieneusi and HEV by molecular assays, followed by sequencing and phylogenetic analysis. We have detected Cryptosporidium scrofarum (1.4%, 95% CI: 0.2-4.9), B. coli (14.6%, 95% CI: 9.2-21.4), Blastocystis ST5 (29.2%, 95% CI: 21.9-37.2) and HEV genotype 3 (2.8%, 95% CI: 0.7-6.9; subgenotypes 3e and 3m). Co-infections were observed in thirteen animals where two were positive for both HEV and B. coli, one was positive for both C. scrofarum and Blastocystis ST5, and ten were positive for both B. coli and Blastocystis ST5. Giardia duodenalis and E. bieneusi were not detected in the surveyed wild boar population. As far as we know, this is the first report describing protist infections by Cryptosporidium spp., B. coli, and Blastocystis sp., as well as the first identification of the emerging HEV genotype 3m in wild boar of Portugal. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Awareness and epidemic-surveillance network implementation measures targeting wild boar are needed to prevent the spread of these pathogenic agents to humans.This research was funded by Fundacao para Ciencia e Tecnologia (FCT), grant number 2021.09461.BD