Bidimensional ray tracing model for the underwater noise propagation prediction

An increasing attention has recently been paid to the effect of the underwater noise field generated by ship activities on the marine environment. Although this problem is widely discussed in international treaties and conventions, it has not yet found a consolidated technical-scientific treatment capable of quantifying the level of underwater noise emissions produced by naval systems. As part of a national research collaboration, a novel code has been developed to predict noise propagation according to the Ray Tracing approach. Such optical geometry-based technique allows for calculating the Transmission Loss (TL) trend in its respective contributions: geometrical loss (due to the distance between the source and receiver), dissipation loss (due to the characteristics of the propagation environment), and reflection loss (due to the surfaces that delimit the field). The simulation requires as input parameters the source info as spatial position, frequency, and sound pressure level (SPL) as well as the sea properties like seabed depth, the speed of sound profile, the layers thickness the water column is divided into, the sea salinity, temperature, and pH. The simulation code provides the SPL spatial distribution useful as a fast industrial tool in the future studies addressed to identify the emission limits for the protection of marine wildlife

Antiferromagnetic phase of the gapless semiconductor V3Al

Discovering new antiferromagnetic compounds is at the forefront of developing future spintronic devices without fringing magnetic fields. The antiferromagnetic gapless semiconducting D03 phase of V3Al was successfully synthesized via arc-melting and annealing. The antiferromagnetic properties were established through synchrotron measurements of the atom-specific magnetic moments, where the magnetic dichroism reveals large and oppositely-oriented moments on individual V atoms. Density functional theory calculations confirmed the stability of a type G antiferromagnetism involving only two-third of the V atoms, while the remaining V atoms are nonmagnetic. Magnetization, x-ray diffraction and transport measurements also support the antiferromagnetism. This archetypal gapless semiconductor may be considered as a cornerstone for future spintronic devices containing antiferromagnetic elements.Comment: Accepted to Physics Review B on 02/23/1

Weakly Coupled Motion of Individual Layers in Ferromagnetic Resonance

We demonstrate a layer- and time-resolved measurement of ferromagnetic resonance (FMR) in a Ni81Fe19 / Cu / Co93Zr7 trilayer structure. Time-resolved x-ray magnetic circular dichroism has been developed in transmission, with resonant field excitation at a FMR frequency of 2.3 GHz. Small-angle (to 0.2 degree), time-domain magnetization precession could be observed directly, and resolved to individual layers through elemental contrast at Ni, Fe, and Co edges. The phase sensitivity allowed direct measurement of relative phase lags in the precession oscillations of individual elements and layers. A weak ferromagnetic coupling, difficult to ascertain in conventional FMR measurements, is revealed in the phase and amplitude response of individual layers across resonance.Comment: 22 pages, 6 figures submitted to Physical Review

Comparative Studies on Different Citrus Cultivars: A Revaluation of Waste Mandarin Components

Peel, pulp and seed extracts of three mandarin varieties, namely Phlegraean mandarin (Citrus reticulata), Kumquat (Citrus japonica), and Clementine (Citrus clementina) were compared and characterised in terms of photosynthetic pigment content, total polyphenols amount, antioxidant activity and vitamin C to assess the amount of functional compounds for each cultivar. The highest polyphenols content was found in the Phlegraean mandarin, especially in peel and seeds, whereas Kumquat exhibited the highest polyphenols amount in the pulp. The antioxidant activity was higher in the peel of Phlegraean mandarin and clementine compared to Kumquat, which showed the highest value in the pulp. The antioxidant activity peaked in the seeds of Phlegraean mandarin. The vitamin C in the Phlegraean mandarin was the highest in all parts of the fruit, especially in the seeds. Total chlorophyll content was comparable in the peel of different cultivars, in the pulp the highest amount was found in clementine, whereas kumquat seeds showed the greatest values. As regards total carotenoids, peel and pulp of clementine exhibited higher values than the other two cultivars, whereas the kumquat seeds were the richest in carotenoids. Among the analysed cultivars Phlegraean mandarin may be considered the most promising as a source of polyphenols and antioxidants, compared to the clementine and Kumquat, especially for the functional molecules found in the seeds. Moreover, regardless of cultivars this study also highlights important properties in the parts of the fruit generally considered wastes

Experimental and numerical research activity on a packed bed TES system

This paper presents the results of experimental and numerical research activities on a packed bed sensible thermal energy storage (TES) system. The TES consists of a cylindrical steel tank filled with small alumina beads and crossed by air used as the heat transfer fluid. Experimental tests were carried out hile varying some operating parameters such as the mass flow rate, the inlet–outlet temperature thresholds and the aspect ratio (length over diameter). Numerical simulations were carried out using a one-dimensional model, specifically developed in the Matlab-Simulink environment and a 2D axisymmetric model based on the ANSYS-Fluent platform. Both models are based on a two-equation transient approach to calculate fluid and solid phase temperatures. Thermodynamic properties were considered to be temperature-dependent and, in the Computational Fluid Dynamics (CFD) model, variable porosity of the bed in the radial direction, thermal losses and the effective conductivity of the alumina beads were also considered. The simulation results of both models were compared to the experimental ones, showing good agreement. The one-dimensional model has the advantage of predicting the axial temperature distribution with a very low computational cost, but it does not allow calculation of the correct energy stored when the temperature distribution is strongly influenced by the wall. To overcome this problem a 2D CFD model was used in this work

Prevalence of antibody to Trypanosoma cruzi in Hispanic-surnamed patients seen at Parkland Health & Hospital System, Dallas, Texas

<p>Abstract</p> <p>Background</p> <p>Chagas disease constitutes an important public health threat in terms of morbidity and mortality in the areas in the United States where immigrant populations from Latin America are conspicuous. We conducted a survey to assess the prevalence of anti-<it>T. cruzi </it>antibody in Hispanic-surnamed patients seen at Parkland Memorial Hospital in Dallas, Texas.</p> <p>Findings</p> <p>Five hundred serum specimens from Hispanic-surnamed patients were tested by a preliminary ELISA method. On a subset of 50 sera confirmatory testing was also performed using an alternative ELISA, indirect immunofluorescence, and TESA immunoblot. For 274 of 500 Hispanic-surnamed patients, we were able to ascertain immigration status upon medical chart review. Of the 274 sera analyzed, one sample tested as positive for anti-<it>T. cruzi </it>antibody by the preliminary ELISA, and by the three confirmatory methods.</p> <p>Conclusions</p> <p>The goal of this study is to increase the awareness of <it>T. cruzi </it>infection and Chagas disease in areas where the Latin American immigrant communities are growing. Our study highlights the importance of testing for Chagas disease in the populations most at risk, and the need for current data on the actual seroprevalence in areas where such immigrant populations are conspicuous. Larger-scale epidemiologic surveys on Chagas disease in the immigrant communities from Latin America are warranted.</p

Serologic diagnosis of celiac disease: May it be suitable for adults?

The diagnosis of coeliac disease (CD) in adult patients requires the simultaneous assessment of clinical presentation, serology, and typical histological picture of villous atrophy. However, several years ago, the European Society of Pediatric Gastroenterology, Hepatology, and Nutrition guidelines approved new criteria for the diagnosis in children: Biopsy could be avoided when anti-transglutaminase antibody (TGA) values exceed the cut-off of × 10 upper limit of normal (ULN) and anti-endomysium antibodies are positive, independently from value. This “no biopsy” approach is a decisive need for pediatric population, allowing to avoid stressful endoscopic procedures in children, if unnecessary. This approach relies on the correlation existing in children between TGA levels and assessment of mucosal atrophy according to Marsh’s classification. Several lines of evidence have shown that patients with villous atrophy have markedly elevated TGA levels. Therefore, we aim to perform a narrative review on the topic in adults. Despite that some studies confirmed that the × 10 ULN threshold value has a very good diagnostic performance, several lines of evidence in adults suggest that TGA cut off should be different from that of pediatric population for reaching a good correlation with histological picture. In conclusion, the heterogeneity of study reports as well as some conditions, which may hamper the serological diagnosis of CD (such as seronegative CD and non-celiac villous atrophy) and are much more common in adults than in children, could represent a limitation for the “no biopsy” approach to CD diagnosis in patients outside the pediatric age

Hyaluronic acid modulates growth, morphology and cytoskeleton in embryonic chick skin fibroblasts

The action that hyaluronic acid (HA) exerts on cell proliferation was investigated in embryonic chick skin fibroblasts at different ages (7-14 days) and in different cell-cycle stages evaluated by flow cytometry (cells maintained with and without serum). Proliferation was estimated by 3H- thymidine incorporation and cell counting. The results demonstrated hyaluronic acid inhibits cell multiplication in all different environmental conditions examined. The inhibitory effect of HA is more evident in 14-day than 7-day old fibroblasts. The ability of HA to modulate 3H-thymidine incorporation did not involve a change in the time required for cells entering the S phase of the replicating cycle, but is due to a smaller number of cells entering in this phase. As the relationships between components of the extracellular matrix (ECM) and the cytoskeleton are known, parallel studies were carried out on some cytoskeleton proteins. Furthermore, by modifying the capacity of cells to adhere to the substrate, HA induced alterations in cell shape and in cytoskeleton components involved in these processes. We may hypothesize that HA, binding specific membrane receptors, affects cell adhesion and morphology inducing less receptivity of fibroblasts to mitogenic stimuli by transmembrane interactions with cytoskeleton

Clinical and Experimental Projects on Chemotherapy of Bladder Tumours

Our clinical and experimental experience with chemotherapy of bladder tumours is reviewed. The routes of drug administrations, drug dosages and combinations, are presented. Adjuvant radiotherapy and chemoprophylaxis of certain tumours are discussed.S. Afr. Med. J., 48, 631 (1974