Passive time reversal acoustic communications through shallow-water internal waves

Author Posting. © IEEE, 2010. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 35 (2010): 756-765, doi:10.1109/JOE.2010.2060530.During a 12-h period in the 2006 Shallow Water Experiment (SW06), binary phase shift keying (BPSK) signals at the carrier frequencies of 813 and 1627 Hz were propagated over a 19.8-km source–receiver range when a packet of strong internal waves passed through the acoustic track. The communication data are analyzed by time reversal processing followed by a single-channel decision feedback equalizer. Two types of internal wave effects are investigated in the context of acoustic communications. One is the rapid channel fluctuation within 90-s data packets. It can be characterized as decreased channel coherence, which was the result of fast sound-speed perturbations during the internal wave passage. We show its effect on the time reversal receiver performance and apply channel tracking in the receiver to counteract such fluctuation. The other one is the long-term (in the scale of hours) performance degradation in the depressed waveguide when the internal waves passed through the acoustic track. Even with channel tracking, the time reversal receiver experiences average 3–4-dB decrease in the output signal-to-noise ratio (SNR). Such long-term performance degradation is explained by the ray approximation in the depressed waveguide.This work was supported by the U.S. Office of Naval Research (ONR) Code 322OA under Grants N00014-07-1-0546 and N00014-06-1019

Short-Cut Method to Assess a Gross Available Energy in a Medium-Load Screw Friction Press

The present study proposed a rapid method, based on a previous universal compression tests, to estimate the required load capacity to cold forge different specimen quantity in a screw press. Accordingly, experimental and theoretical approach are performed to check new adjustable drive motor of the modified forging machine to achieve a gross available energy to deform the specimens preventing damage of the forging machine. During the forging experiments, two screw friction presses (as-received and modified) are used to validate the theoretical approach. The modified press exhibits an increase of 51% of gross energy and 11% of maximum load capacity compare to the as-received press. This method is used to improve the effective of the forging process avoiding excessive loads that could promote machine failure. Therefore, a low-cost and easy to implement methodology is proposed to determine the energy and load capacity of a screw friction press to forge different specimen quantities with symmetry pattern configurations.This work is supported by the Ministry of Economy and Competitiveness of Spain (reference project: FJCI-2016-29297), Instituto Nacional de Tecnologia Industrial (INTI) of Argentina and the Aeronautics Advanced Manufacturing Center (CFAA) of Bilbao

Antarctic network of lamp-calibrated multichannel radiometers for continuous ozone and uv radiation data

International audienceThree NILU-UV multichannel radiometers have been installed in 1999 at the Argentinian sites of Ushuaia (54S), Marambio (64S) and Belgrano-II (77S) in order to continuously monitor UV radiation, photosynthetically active radiation and total ozone. The measurements were established by INM, Spain in collaboration with FMI, Finland, DNA-IAA, Argentina and CADIC, Argentina to observe and characterize the spatial and temporal evolution of ozone and ultraviolet radiation in the Antarctic region. Special attention has been given to the quality control and quality assurance of the measurements under harsh climatological conditions. The ozone and UV time series of 2000?2006 were calibrated using a polynomial fit for lamp measurements performed every second week all year round. The gaps in these data are minimal, with almost no data missing, and the data products are available from http://www.polarvortex.org in near real time. The data products include the erythemally-weighted UV, UVB and UVA radiation, photosynthetically active radiation (PAR), total ozone (O3) and a cloud parameter (CLT). For UV data, dose rates as well as daily doses are available; from these the maximum measured UV indices (UVI), during 2000?2006, were 12.0, 9.7 and 8.1 at Ushuaia, Marambio and Belgrano-II, respectively

Effect on Irradiance of the eruption of the Cordon Caulle (Chile) at different altitudes in the Nahuel Huapi National Park (Patagonia, Argentina)

Volcanic eruptions inject ash and non-ash particles into the atmosphere, modifying regional Aerosols Optical Depth (AOD) and aerosols size distribution, which affect irradiance at the earth’s surface. In this paper, we analyze the effect of the eruption of Puyehue-Cordon Caulle (Chile) on irradiance in the area of the Nahuel Huapi National Park (NHNP) (~100 km southeast of Puyehue-Cordon Caulle), at different altitudes. In this paper we only included the results for direct and AOD obtained during field campaigns at two consecutive years, before and after the eruption. Three days presented clear skies during most of the day in 2011. Two of those days, showed AOD similar to the values in 2010. On the third days, at the lowest altitude site (804m.s.l.), AOD were near 200% larger than in 2010. The largest decreases observed, at noon, in the direct irradiance was ~30% at 380 nm and 25% at 500nm, increasing with Solar Zenith Angle (SZA). The effect was less pronounced at the site at highest altitude (1930 m.s.l.), where the AODs increase was near 90% and the direct noon irradiance decrease 10% at 380 nm and 7% at 500nm. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.Fil: Diaz, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Paladini, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Braile, H. G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Dieguez, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vernet, María. University of California at San Diego; Estados UnidosFil: Vrsalovic, Jazmin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

UV measurements at Marambio and Ushuaia during 2000–2010

Solar ultraviolet (UV) irradiances were measured with NILU-UV multichannel radiometers at Ushuaia (54°&thinsp;S) and Marambio (64°&thinsp;S) between 2000 and 2013. The measurements were part of the Antarctic NILU-UV network, which was started in cooperation between Spain, Argentina and Finland. The erythemally weighted UV irradiance time series of both stations were analysed for the first time. The quality assurance procedures included a travelling reference instrument to transfer the irradiance scale to the stations. The time series were homogenized and high quality measurements were available for the period 2000–2010. During this period UV indices of 11 or more were measured on 5 and 35 days at Marambio and Ushuaia, respectively. At Marambio, the peak daily maximum UV index of 12 and daily doses of around 7&thinsp;kJ&thinsp;m−2 were measured in November 2007. The highest UV daily doses at both stations were typically around 6&thinsp;kJ&thinsp;m−2 and occurred when the stations were inside the polar vortex, resulting in very low total ozone amount. At both stations, daily doses in late November could even exceed those in the summer. At Marambio, in some years, also daily doses in October can be as high as those during the summer. At Ushuaia, the peak daily maximum UV index of 13 was measured twice: in November 2003 and 2009. Also during those days, the station of Ushuaia was inside the polar vortex.</p

Suplementação de ferro em pacientes com insuficiência renal crônica em hemodiálise: um ensaio clínico

OBJECTIVE: To evaluate iron deficiency and to compare effectiveness of oral and parenteral iron supplementation in end-stage renal disease, hemodialysis patients.PATIENTS AND METHODS: Thirty-nine end-stage renal disease, hemodialysis patients were evaluated for age; weight; etiology of chronic renal failure; duration of hemodialysis;  use of recombinant human erythropoietin; serum albumin, serum hemoglobin, hematocrit, and serum ferritin levels; and iron status. Iron status was assessed based on the following equation: [400 x log (serum ferritin) - log 30] - [150 x (11.55 - hemoglobin)] =iron status Patients were considered iron-deficient when the equation gave a negative result. Next, these patients were randomly divided into 2 groups. Patients with recent bleeding episodes or blood transfusion were excluded from the study. Group I received oral iron sulfate and group II intravenous iron hydroxide saccharate. The dosage was calculated basedon the iron status and body weight and adjusted for estimated bioavailability. RESULTS: Twenty-four (62%) patients were iron-deficient, out of which 19 completed the trial (11 patients in group I and 8 in group II). In the comparison with baseline values, group II had a significant increase in hematocrit (3.25 ± 3.69%, P &lt; 0.05), serum hemoglobin (0.98 ± 0.86 g/dl, P &lt; 0.02), serum ferritin (245 ± 133 ng/ml, P &lt;0.01) and iron status (316.20 ± 214.230 mg, P &lt; 0.01), whereas group I did not. In the comparison of group I and group II, the latter indicated greater increase in hematocrit, serum hemoglobin, serum ferritin and iron status (P &lt; 0.05). Group II patients not using erythropoietin (5 of 8 patients), when compared to Group I, presented a greater increase in serum hemoglobin (0.8 ± 0.6 g/dl) and hematocrit (2.2± 3.4 %, P &lt; 0.05). CONCLUSIONS: Considering equivalent dosages, intravenous iron therapy was more effective than oral therapy in increasing hematocrit, serum hemoglobin, serum ferritin, and iron status in hemodialysis patients with chronic renal disease. Patients not usingrecombinant human erythropoietin could benefit only from intravenous iron therapy.OBJETIVOS: Avaliar deficiência de ferro e comparar a efetividade da suplementação de ferro oral e parenteral nos pacientes renais crônicos em hemodiálise. PACIENTES E MÉTODOS: Trinta e nove pacientes com insuficiência renal crônica em hemodiálise foram avaliados para idade, peso, etiologia da insuficiência renal crônica, tempo em hemodiálise, uso de eritropoetina humana recombinante, albumina sérica,níveis de hematócrito e hemoglobina, ferritina sérica e grau de deficiência de ferro. Grau de deficiência de ferro foi avaliado pela equação: estado de ferro = [400 x log (ferritina sérica) - log 30] - [150 x (11,55 - hemoglobinasérica)] Deficiência de ferro foi considerada quando o resultado da equação era negativo. Estes pacientes foram randomizados aleatoriamente em 2 grupos. Os que apresentaram episódio de sangramento ou transfusão sanguínea recentes foram excluídos do estudo. O Grupo I recebeu ferro oral e o Grupo II, sacarato de hidróxido de ferro endovenoso. A dose foi calculada com base no estado de ferro e peso corporal e ajustada para biodisponibilidade estimada. RESULTADOS: Vinte e quatro pacientes (62%) estavam deficientes de ferro, sendo que 19 destes completaram o estudo, 11 pacientes no Grupo I e 8 no Grupo II . Comparado aos valores pré-tratamento com ferro, o Grupo II apresentou aumentossignificativos nos níveis de hematócrito (3,25 ± 3,69%, P &lt; 0,05), hemoglobina sérica (0,98 ± 0,86g/dl, P &lt; 0,02), ferritina sérica (245 ± 133ng/ml, P &lt; 0,01) e no estado de ferro (316,20 ± 214,230mg, P &lt; 0,01), o mesmo não ocorrendo no Grupo I. Ao comparar os dois grupos, o Grupo II apresentou aumentos maiores no hematócrito, hemoglobina sérica, ferritina sérica e estado de ferro do que o grupo I (P &lt; 0,05). Cinco pacientes (62,5%) não usando eritropoetina (Grupo II) tiveram  aumentos maiores no hematócrito (2,2±3,4%) e na hemoglobina sérica (0,8±0,6g/dl) (P&lt;0,05) comparados aos do Grupo I.CONCLUSÕES: Em doses equivalentes, a suplementação endovenosa de ferro foi mais efetiva do que a reposição oral em aumentar os níveis de hematócrito, hemoglobina sérica, ferritina sérica e estado de ferro nos pacientes renais crônicos em hemodiálise. Pacientes não usando eritropoetina humana recombinante apresentaram benefício somente com a suplementação parenteral de ferro na anemia.

Effect of the Monocyte Chemoattractant Protein-1/CC Chemokine Receptor 2 System on Nephrin Expression in Streptozotocin-Treated Mice and Human Cultured Podocytes

OBJECTIVE-Monocyte chemoattractant protein-1 (MCP-1), a chemokine binding to the CC chemokine receptor 2 (CCR2) and promoting monocyte infiltration, has been implicated in the pathogenesis of diabetic nephropathy. To assess the potential relevance of the MCP-1/CCR2 system in the pathogenesis of diabetic proteinuria, we studied in vitro if MCP-1 binding to the CCR2 receptor modulates nephrin expression in cultured podocytes. Moreover, we investigated in vivo if glomerular CCR2 expression is altered in kidney biopsies from patients with diabetic nephropathy and whether lack of MCP-1 affects proteinuria and expression of nephrin in experimental diabetes. RESEARCH DESIGN AND METHODS-Expression of nephrin was assessed in human podocytes exposed to rh-MCP-1 by immunofluorescence and real-time PCR. Glomerular CCR2 expression was studied in 10 kidney sections from patients with overt nephropathy and eight control subjects by immunohistochemistry. Both wild-type and MCP-1 knockout mice were made diabetic with streptozotocin. Ten weeks after the onset of diabetes, albuminuria and expression of nephrin, synaptopodin, and zonula occludens-1 were examined by immunofluorescence and immunoblotting. RESULTS-In human podocytes, MCP-1 binding to the CCR2 receptor induced a significant reduction in nephrin both mRNA and protein expression via a Rho-dependent mechanism. The MCP-1 receptor, CCR2, was overexpressed in the glomerular podocytes of patients with overt nephropathy. In experimental diabetes, MCP-1 was overexpressed within the glomeruli and the absence of MCP-1 reduced both albuminuria and downregulation of nephrin and synaptopodin. CONCLUSIONS-These findings suggest that the MCP-1/CCR2 system may be relevant in the pathogenesis of proteinuria in diabetes