1,194 research outputs found

    The tidal prism as a dynamic response of a nonlinear harmonic system

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    As known, the empirical relationship between the equilibrium cross-sectional area of a lagoon inlet and the tidal prism was intuited for the first time by LeConte ["Discussion on the paper, "Notes on the improvement of river and harbor outlets in the United States"by D. A. Watt,"Trans. ASCE 55, 306-308 (1905).] and then formalized by O'Brien ["Estuary tidal prism related to entrance areas,"Civ. Eng. 1(8), 738-739 (1931)]. This relationship requires knowledge of the tidal prism, which can be estimated either using the cubature method or the current data method [Jarrett, Tidal Prism-Inlet Area Relationships (Coastal Engineering Research Center, US Army Corps of Engineers, Fort Belvoir, VA, 1976)], both of which involve the execution of a number of experimental measurements. However, these methods, besides being very expensive, can only provide the prism value in the present condition and do not allow for predictions in the case of significant morphological changes, of both natural and anthropic origin, to the tidal inlet. On the other hand, the hydrodynamic relationship, which links the tidal prism to the product of the tidal range and the basin extension, can only give a coarse estimate of the prism, especially when the value of the tide outside the lagoon is considered. In this work, we propose a simple hydrodynamic relationship based on the dynamic response of a nonlinear harmonic system. This is a relationship that requires the calibration of a single physically based parameter. Through this relationship, knowing the geometric characteristics, the bottom friction of the inlet channel, the surface of the basin, and the tide amplitude in the open sea, it is possible to estimate the tidal prism. The application of this relationship to real cases shows a good agreement with the experimental data

    Phase Nanoengineering via Thermal Scanning Probe Lithography and Direct Laser Writing

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    Nanomaterials derive their electronic, magnetic, and optical properties from their specific nanostructure. In most cases, nanostructured materials and their properties are defined during the materials growth, and nanofabrication techniques, such as lithography, are employed subsequently for device fabrication. Herein, a perspective is presented on a different approach for creating nanomaterials and devices where, after growth, advanced nanofabrication techniques are used to directly nanostructure condensed matter systems, by inducing highly controlled, localized, and stable changes in the electronic, magnetic, or optical properties. Then, advantages, limitations, applications in materials science and technology are highlighted, and future perspectives are discussed

    A Rapid Assessment of the Quality of Neonatal Healthcare in Kilimanjaro Region, Northeast Tanzania.

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    While child mortality is declining in Africa there has been no evidence of a comparable reduction in neonatal mortality. The quality of inpatient neonatal care is likely a contributing factor but data from resource limited settings are few. The objective of this study was to assess the quality of neonatal care in the district hospitals of the Kilimanjaro region of Tanzania. Clinical records were reviewed for ill or premature neonates admitted to 13 inpatient health facilities in the Kilimanjaro region; staffing and equipment levels were also assessed. Among the 82 neonates reviewed, key health information was missing from a substantial proportion of records: on maternal antenatal cards, blood group was recorded for 52 (63.4%) mothers, Rhesus (Rh) factor for 39 (47.6%), VDRL for 59 (71.9%) and HIV status for 77 (93.1%). From neonatal clinical records, heart rate was recorded for3 (3.7%) neonates, respiratory rate in 14, (17.1%) and temperature in 33 (40.2%). None of 13 facilities had a functioning premature unit despite calculated gestational age <36 weeks in 45.6% of evaluated neonates. Intravenous fluids and oxygen were available in 9 out of 13 of facilities, while antibiotics and essential basic equipment were available in more than two thirds. Medication dosing errors were common; under-dosage for ampicillin, gentamicin and cloxacillin was found in 44.0%, 37.9% and 50% of cases, respectively, while over-dosage was found in 20.0%, 24.2% and 19.9%, respectively. Physician or assistant physician staffing levels by the WHO indicator levels (WISN) were generally low. Key aspects of neonatal care were found to be poorly documented or incorrectly implemented in this appraisal of neonatal care in Kilimanjaro. Efforts towards quality assurance and enhanced motivation of staff may improve outcomes for this vulnerable group

    Eutrophication and macroalgal blooms in temperate and tropical coastal waters: Nutrient enrichment experiments with Ulva spp.

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    Receiving coastal waters and estuaries are among the most nutrient-enriched environments on earth, and one of the symptoms of the resulting eutrophication is the proliferation of opportunistic, fast-growing marine seaweeds. Here, we used a widespread macroalga often involved in blooms, Ulva spp., to investigate how supply of nitrogen (N) and phosphorus (P), the two main potential growth-limiting nutrients, influence macroalgal growth in temperate and tropical coastal waters ranging from low- to high-nutrient supplies. We carried out N and P enrichment field experiments on Ulva spp. in seven coastal systems, with one of these systems represented by three different subestuaries, for a total of nine sites. We showed that rate of growth of Ulva spp. was directly correlated to annual dissolved inorganic nitrogen (DIN) concentrations, where growth increased with increasing DIN concentration. Internal N pools of macroalgal fronds were also linked to increased DIN supply, and algal growth rates were tightly coupled to these internal N pools. The increases in DIN appeared to be related to greater inputs of wastewater to these coastal waters as indicated by high δ15N signatures of the algae as DIN increased. N and P enrichment experiments showed that rate of macroalgal growth was controlled by supply of DIN where ambient DIN concentrations were low, and by P where DIN concentrations were higher, regardless of latitude or geographic setting. These results suggest that understanding the basis for macroalgal blooms, and management of these harmful phenomena, will require information as to nutrient sources, and actions to reduce supply of N and P in coastal waters concerned.Fil: Teichberg, Mirta. Leibniz Center For Tropical Marine Research; AlemaniaFil: Fox, Sophia E.. Marine Biological Laboratory; Estados UnidosFil: Olsen, Ylva S.. Bangor University; Reino UnidoFil: Valiela, Ivan. Marine Biological Laboratory; Estados UnidosFil: Martinetto, Paulina Maria del Rosario. Universidad Nacional de Mar del Plata; ArgentinaFil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Muto, Elizabeti Yuriko. Universidade de Sao Paulo; BrasilFil: Petti, Monica A.V.. Universidade de Sao Paulo; BrasilFil: Corbisier, Thaïs N.. Universidade de Sao Paulo; BrasilFil: Soto-Jiménez, Martín. Universidad Nacional Autónoma de México; MéxicoFil: Páez-Osuna, Federico. Universidad Nacional Autónoma de México; MéxicoFil: Castro, Paula. University Of Coimbra; BrasilFil: Freitas, Helena. University Of Coimbra; BrasilFil: Zitelli, Andreina. Università Iuav Di Venezia; ItaliaFil: Cardinaletti, Massimo. Gruppo Veritas; ItaliaFil: Tagliapietra, Davide. Consiglio Nazionale delle Ricerche; Itali

    Single-cell RNA-sequencing reveals Transcriptional Changes and Clonal Architecture associated with Post-Transplant Relapse in Acute Myeloid Leukemia

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    "Acute myeloid leukemia (AML) is a malignancy characterized by overproduction of myeloid precursors at the expense of more differentiated, functional hematopoietic cells, resulting in anemia, thrombocytopenia, and neutropenia. Despite initial sensitivity to chemotherapy, a majority of patients with AML ultimately relapse. Among the challenges associated with relapse, post-allogeneic stem cell transplant relapse is particularly intractable because of our relative lack of understanding - and thus lack of effective treatment options - of the underlying mechanisms."--IntroductionZiheng Xu (1), Christopher A. Miller (2, 3), Sridhar N. Srivatsan (2), Catrina C. Fronick (3), Robert S. Fulton (3), Timothy J. Ley (2, 3, 4), and Allegra A. Petti (2, 3) ; 1. Washington University School of Medicine. 2. Division of Oncology, Washington University School of Medicine. 3. McDonnell Genome Institute, Washington University School of Medicine. 4. Department of Genetics, Washington University School of Medicine.Includes bibliographical reference
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