59 research outputs found

    STUDIES IN PERIODIC PRECIPITATION

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    Gewisse morphologische, physiognomische und antropologische Merkmale bei einwohnern eines jugoslawischen Küstengebiets

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    Autori su obavili analizu nalaza 498 ispitanika obaju spolova djece starosjedilaca (najmanje jedna generacija) u Solinu i Kaštelima. Ispitivanja su provedena kod djece stare 10—14 godina, s namjerom da se pridonese prikupljanju podataka nacionalnih obilježja. Ispitivanja su po karakteru sondažna. Problematika se je sastojala u tome da se utvrdi postoje li signifikantni nalazi i njihove međusobne korelacije. Ispitivanja su obavljena u području identične geografske širine, u kojoj je obavljao ispitivanja i Francuz Pont30, s namjerom da se ustanovi da li utvrđeni indeks odgovara onom spomenutog autora. Mjerenja, su izvedena standardnim instrumentarijem, a vršila ih je ekipa od triju članova, koautora ovog rada, koja je prethodno prošla blind test, konstruiran za ispitivanja te vrsti. Unošenje i obrada podataka učinjeno je na obrascima za ortodontske sistematske preglede (rubno bušene kartice br. 1226/038). Rezultati su komparirani s nalazima stranih autora. Utvrđeno je između ostalog da je SI i parametar Zy-Zy veći kod muških ispitanika. PŠ i SŠ su u cijelosti veće kod ispitanika bez anomalija. Usporedbene vrijednosti dobivenog indeksa za PŠ i SŠ vrlo su blizu mjerama po Pontu30, što potvrđuje pretpostavku, da se je radilo o ispitanicima sa širokim čeljustima. Statistička obrada vlastitih podataka prikazana je na tab. 1., dok ostale tablice prikazuju rezultate stranih autora. Tab. 2 i 4 sadrže i vlastite rezultate zbog preglednije komparacije. Autori se kritički osvrću na pomanjkanje standardne metodike u ispitivanjima te vrsti u nacionalnoj stomatološkoj literaturi Njemačke i Jugoslavije.The authors published an analysis of the findings in 498 test subjects of both sexes, children of the indigenes (at least one generation) of Solin and Kaštela. The testing was carried out in children aged between 10 to 14 for the purpose of contributing to the collection of data on national characteristics. The tests had a probing character and were meant to investigate the problem whether there existed any significant findings and to establish their mutual correlation. Testings were carried out in a region of identical geographical latitude to that in which the Frenchman Pont made his investigations (30). The aim was to establish whether the index obtained corresponded to that of the mentioned author. Measuring was carried out by means of standard instruments and a team consisting of three members, coauthors of this paper, was engaged in the task. The team had previously undergone the blind test for investigations of that kind. The elaboration and entry of data was made on forms for ortodontic systematic examinations (punch cards no. 1226/038). The results were compared1 to^ the findings of the foreign authors. It was ascertained that the width of the upper incisors and the distance Zy-Zy were higher in boys. Anterior and posterior widths of the upper dental arch were higher in subjects without malocclusions. The obtained values for both widths of the dental arch were very close to those of Pont, thus confirming the hypothesis that the test subjects had wide jaws. The statistical elaboration of our own data is shown in Table 1, while the other tables show the results of foreign authors. Table 2 and 4 contain also our own results for easier comparison. The authors point out at the lack of standard methods in investigations of that kind in the national German and Yugoslav dental literature.Die Autoren haben eine Befunderhebung bei 498 Kindern beiderlei Geschlechts von Alteingesessenen in Solin und Kaštela auf gewisse Merkmale, durchgeführt. Die Untersuchungen wurden an Kindern im Alter von 10 bis 14 Jahren gemacht, mit der Absicht Beiträge für nationale Merkmale zu sammeln. Es sollte festgestellt werden ob deutliche Befunde erhoben werden können, und ihre gegen seitigen Zusammenhänge geprüft werden. Die Untersuchungen wurden in Gebieten der gleichen geographischen Breite durchgeführt, in welchen auch der Franzose Pont seine Untersuchungen anstellte, mit der Absicht festzustellen ob der erhaltene Index dem Pontschen-Index gleich ist. Die Messungen wurden von den drei Koautoren dieser Arbeit mit standardisierten Methoden ausgeführt. Die Resultate wurden mit Befunden anderer Autoren verglichen. Unter Anderem wurde festgestellt, dass die Sl und der Parameter Zy-Zy bei männlichen Probanaen grösser ist. Die vordere und die hintere obere Zahn bogen breite ist im Ganzen grösser bei Untersuchten die keine Anomalien aufwiesen. Der Vergleichswert der erhaltenen Indexe für die angeführten Breiten sind den Pont - Werten sehr nahe, was die Vorraussetzung bestätigt, dass es sich um Probanden mit breiten Kiefern handelt. Die statistische Bearbeitung der eigenen Befunde ist auf Tabelle 1 dargestellt, während die übrigen Tabellen Resultate anderer Autoren zeigen. Die Tabellen 2 und 4 behalten auch eigene Resultate, wegen besserer Übersicht bei der Vergleichung. Die Autoren beanständen das Fehlen einer Standard- -Methode für Untersuchungen dieser Art in der nationalen stomatologischen Literatur Deutschlands und Jugoslawiens

    Installing oncofertility programs for common cancers in optimum resource settings (Repro-Can-OPEN Study Part II): a committee opinion

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    The main objective of Repro-Can-OPEN Study Part 2 is to learn more about oncofertility practices in optimum resource settings to provide a roadmap to establish oncofertility best practice models. As an extrapolation for oncofertility best practice models in optimum resource settings, we surveyed 25 leading and well-resourced oncofertility centers and institutions from the USA, Europe, Australia, and Japan. The survey included questions on the availability and degree of utilization of fertility preservation options in case of childhood cancer, breast cancer, and blood cancer. All surveyed centers responded to all questions. Responses and their calculated oncofertility scores showed three major characteristics of oncofertility practice in optimum resource settings: (1) strong utilization of sperm freezing, egg freezing, embryo freezing, ovarian tissue freezing, gonadal shielding, and fractionation of chemo- and radiotherapy; (2) promising utilization of GnRH analogs, oophoropexy, testicular tissue freezing, and oocyte in vitro maturation (IVM); and (3) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, in vitro spermatogenesis, and stem cell reproductive technology as they are still in preclinical or early clinical research settings. Proper technical and ethical concerns should be considered when offering advanced and experimental oncofertility options to patients. Our Repro-Can-OPEN Study Part 2 proposed installing specific oncofertility programs for common cancers in optimum resource settings as an extrapolation for best practice models. This will provide efficient oncofertility edification and modeling to oncofertility teams and related healthcare providers around the globe and help them offer the best care possible to their patients

    Arctic marine secondary organic aerosol contributes significantly to summertime particle size distributions in the Canadian Arctic Archipelago

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    Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with size-resolved aerosol microphysics (GEOS-Chem-TOMAS) to interpret measurements of aerosol size distributions from the Canadian Arctic Archipelago during the summer of 2016, as part of the “NETwork on Climate and Aerosols: Addressing key uncertainties in Remote Canadian Environments” (NETCARE) project. Our simulations suggest that condensation of secondary organic aerosol (SOA) from precursor vapors emitted in the Arctic and near Arctic marine (ice-free seawater) regions plays a key role in particle growth events that shape the aerosol size distributions observed at Alert (82.5∘&thinsp;N, 62.3∘&thinsp;W), Eureka (80.1∘&thinsp;N, 86.4∘&thinsp;W), and along a NETCARE ship track within the Archipelago. We refer to this SOA as Arctic marine SOA (AMSOA) to reflect the Arctic marine-based and likely biogenic sources for the precursors of the condensing organic vapors. AMSOA from a simulated flux (500&thinsp;µgm-2day-1, north of 50∘&thinsp;N) of precursor vapors (with an assumed yield of unity) reduces the summertime particle size distribution model–observation mean fractional error 2- to 4-fold, relative to a simulation without this AMSOA. Particle growth due to the condensable organic vapor flux contributes strongly (30&thinsp;%–50&thinsp;%) to the simulated summertime-mean number of particles with diameters larger than 20&thinsp;nm in the study region. This growth couples with ternary particle nucleation (sulfuric acid, ammonia, and water vapor) and biogenic sulfate condensation to account for more than 90&thinsp;% of this simulated particle number, which represents a strong biogenic influence. The simulated fit to summertime size-distribution observations is further improved at Eureka and for the ship track by scaling up the nucleation rate by a factor of 100 to account for other particle precursors such as gas-phase iodine and/or amines and/or fragmenting primary particles that could be missing from our simulations. Additionally, the fits to the observed size distributions and total aerosol number concentrations for particles larger than 4&thinsp;nm improve with the assumption that the AMSOA contains semi-volatile species: the model–observation mean fractional error is reduced 2- to 3-fold for the Alert and ship track size distributions. AMSOA accounts for about half of the simulated particle surface area and volume distributions in the summertime Canadian Arctic Archipelago, with climate-relevant simulated summertime pan-Arctic-mean top-of-the-atmosphere aerosol direct (−0.04&thinsp;W m−2) and cloud-albedo indirect (−0.4&thinsp;W m−2) radiative effects, which due to uncertainties are viewed as an order of magnitude estimate. Future work should focus on further understanding summertime Arctic sources of AMSOA.</p

    Overview paper: New insights into aerosol and climate in the Arctic

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    Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013. (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water (up to 75&thinsp;nM) and the overlying atmosphere (up to 1&thinsp;ppbv) in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source (with DMS concentrations of up to 6&thinsp;nM and a potential contribution to atmospheric DMS of 20&thinsp;% in the study area). (2) Evidence of widespread particle nucleation and growth in the marine boundary layer was found in the CAA in the summertime, with these events observed on 41&thinsp;% of days in a 2016 cruise. As well, at Alert, Nunavut, particles that are newly formed and grown under conditions of minimal anthropogenic influence during the months of July and August are estimated to contribute 20&thinsp;% to 80&thinsp;% of the 30–50&thinsp;nm particle number density. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from seabird-colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic aerosol (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds (OVOCs) were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol–climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms, with evidence for a dominant springtime contribution from eastern and southern Asia to the middle troposphere, and a major contribution from northern Asia to the surface. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow (0.03&thinsp;cm&thinsp;s−1).</p

    Forced Periodic Temperature Oscillations in Microchannel Reactors

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    Use of metallic nanoparticles to improve the thermophysical properties of organic heat transfer fluids used in concentrated solar power

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    One of the approaches to enhance the efficiency, and consequently, reduce costs to produce electricity from concentrated solar power (CSP) is by the development of advanced high temperature heat transfer fluids (HTFs). Incorporation of metallic nanoparticles into conventional heat transfer fluids could significantly improve the thermal transport properties of the HTFs. This study reports on the synthesis and investigation of copper nanoparticles synthesized in-house and dispersed in two synthetic HTFs Therminol 59 (TH59) and Therminol 66 (TH66). Liquid phase reduction of a copper salt was used to produce copper nanoparticles. Suspensions with various copper nanoparticle loadings (0.5-2 vol.%) were prepared. Characterizations such as the thermal conductivity, dynamic viscosity, mass specific heat capacity, and fluid stability were performed on the suspensions. Thermal conductivity enhancements over the base fluids were as high as approximately 20% at a 2 vol.% particle loading. These enhancements in the thermal conductivity are higher than the predictions based on the Effective Medium Theory (EMT). Dynamic viscosity measurements showed that if good dispersion of nanoparticles is achieved, the composite fluids behave in a Newtonian manner and the dynamic viscosity increases over the base fluid are minor at temperatures 125 C and above. Stability of the suspensions with time was also investigated. Based on the measured properties of the suspensions, a figure of merit for heat transfer was calculated to evaluate the viability of the suspensions. (C) 2014 Elsevier Ltd. All rights reserved
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