bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation-induced decomposition of U(VI) alteration phases of UO2
Authors: Utsunomiya Satoshi , Ewing Rodney C.
Published: April 2011

U6+−phases are common alteration products of spent nuclear fuel under oxidizing conditions, and they may potentially incorporate actinides, such as long-lived 239Pu and 237Np, delaying their transport to the biosphere. In order to evaluate the ballistic effects of α-decay events on the stability of the U6+−phases, we report, for the first time, the results of ion beam irradiations (1.0 MeV Kr2+) for six different structures of U6+-phases: uranophane, kasolite, boltwoodite, saleeite, carnotite, and liebigite. The target uranyl-minerals were characterized by powder X-ray diffraction and identification confirmed by SAED (selected area electron diffraction) in TEM (transmission electron microscopy). The TEM observation revealed no initial contamination of uraninite in these U6+ phases. All of the samples were irradiated with in situ TEM observation using 1.0 MeV Kr2+ in the IVEM (intermediate-voltage electron microscope) at the IVEM-Tandem Facility of Argonne National Laboratory. The ion flux was 6.3 × 1011 ions/cm2/sec. The specimen temperatures during irradiation were 298 and 673 K, respectively. The Kr2+-irradiation decomposed the U6+-phases to nanocrystals of UO2 at doses as low as 0.006 dpa. The cumulative doses for the pure U6+-phases, e.g., uranophane, at 0.1 and 1 million years (m.y.) are calculated to be 0.009 and 0.09 dpa using SRIM2003. However, with the incorporation of 1 wt.% 239Pu, the calculated doses reach 0.27 and ∼1.00 dpa in ten thousand and one hundred thousand years, respectively.

Under oxidizing conditions, multiple cycles of radiation-induced decomposition to UO2 followed by alteration to U6+-phases should be further investigated to determine the fate of trace elements that may have been incorporated in the U6+-phases.
Electrochemical, SECM, and XPS Studies of the Influence of H2 on UO2 Nuclear Fuel Corrosion
Authors: Broczkowski Michael E. , Zhu R. , Ding Z. , Noël J.J. , Shoesmith D.W.
Published: April 2011

A combination of electrochemical, scanning electrochemical microscopy (SECM), X-ray photoelectron spectroscopic (XPS), and time of flight secondary ion mass spectrometry (TOF - SIMS) techniques are being employed to investigate the effects of dissolved hydrogen on the aqueous corrosion of uranium dioxide (UO2) under nuclear waste disposal conditions. Corrosion potential (ECORR) measurements indicate that the oxidation of dissolved hydrogen on noble metal ε-particles polarizes the UO2 nuclear fuel surface to reducing potentials (−300 – −400 mV vs. SCE; i.e., to ECORR values more negative than those observed under anoxic (argon-purged) conditions (−200 mV vs. SCE). A comparison of the behaviors observed on SIMFUEL specimens with and without incorporated noble metal ε-particles indicate that these particles may act as catalytic electrodes for H2 oxidation. It is the galvanic coupling of these particles to the UO2 matrix which suppresses the fuel corrosion potential thereby preventing oxidation of the fuel surface.
Factors influencing the sulphate incorporation in radioactive waste glasses
Authors: Manara D. , Grandjean A. , Pinet O. , Dussossoy J.L. , Neuville D.R.
Published: April 2011

Sulphur is present in several kinds of nuclear waste destined to confinement in a glass matrix.. These species are hardly incorporated in borosilicate glasses, due to the poor miscibility of molten sulphates and glass melt at high temperature. This point constitutes one of the main technological difficulties in the current fabrication of nuclear glasses. Several studies carried out in the last two decades indicate that the liquid state miscibility of sulphates and glass melt, determining the waste incorporation in the final glass, is dependent on the composition of the glass and on the temperature and duration of its preparation. In particular, the ratios K = [SiO2] / [B2O3] and R = [Na2O] / [B2O3] (where [.] indicates the mol %), as well as the presence of V2O5 in the glass matrix play an important role in the determination of both kinetics and thermodynamics of sulphates incorporation in the vitreous matrix. In this work a study on the physico-chemical effects of the ratio R, the melt reactivity, the type of sulphate added, and the presence of V2O5 on the solubility of sulphates in borosilico-vanadate glasses is presented.

Glass samples were prepared at the laboratory scale (up to 50-100 g) by melting oxide and sulphate powders in Pt/Au or Pt/Rh crucibles at a fixed viscosity level of 100 Po in air. Several glass specimens were powdered and re-melted at 1200°C in the presence of sulphates in order to simulate conditions as close as possible to those of an industrial melter. XRF and ICP AES chemical analysis, SEM EDS and Raman spectroscopy were employed to characterise the fabricated samples. Raman spectra, in particular, reveal the structural modifications that condition the sulphate incorporation in the glass. A critical review of the obtained results is compared with the literature data, to yield a more systematic description of the mentioned factors effects on sulphate behaviour in the borosilico-vanadate / system.
Static dissolution tests of α-doped UO2 under repository relevant conditions: Influence of Boom Clay and α-activity on fuel dissolution rates
Authors: Salah Sonia , Cachoir Christelle , Lemmens Karel , Maes Norbert
Published: April 2011

Since reprocessing is no longer the reference policy in Belgium, studies on the direct disposal of spent fuel in a clay formation have gained increased interest in the last years. In order to determine to what extent the clay properties and the α-activity influence the dissolution kinetics of spent fuel for the long term disposal, static dissolution tests have been performed on 5 different types of α-doped UO2, representing a PWR fuel with a burn-up of 45 or 55 GWd · tHM−1 and fuel ages ranging between 150 and 90,000 years, in different Boom Clay (BC) media at room temperature and in an anoxic atmosphere for 90 to 720 days. The uranium activity in the clay fraction over time was found to be much higher than the U-activity in the leachates, which has been mainly ascribed to the high retention capacity of the BC. The average dissolution rate between 0 and 90 days obtained for the 5 types of α-doped UO2 were all found to be high and quite similar at ~263 µg · m−2 · d−1and a “longer-term” rate (181 to 720 days) ranging between zero and 15 µg · m−2· d−1. These results suggest that the activity of the fuels does not seem to have an effect on the UO2 dissolution rates under the considered test conditions. In order to study the partition/redistribution of U during UO2dissolution, sequential extraction experiments were performed. Results of the latter have provided a better mechanistic understanding of BC/spent fuel interaction processes as well as information on the role of the different minerals controlling the U-retention/immobilization.
HLW-Glass Dissolution and Co-Precipitation Studies
Authors: Luckscheiter Berthold , Nesovic Maria
Published: April 2011

To determine the maximum attainable solution concentrations of U, Th and fission products during long-term glass corrosion, co-precipitation studies were performed. The HLW-glass GPWAK 1 was dissolved in highly acid and basic media (100 g glass/L) at 80°C and by preparing acid solutions containing the various elements in soluble form. After dissolution the pH of the solution was slowly lowered/increased and the high concentrated solutions become super-saturated and strong precipitation takes place. The found pH-dependent concentrations of the various elements reflect their different solubility, lowest concentration for Th, Zr and Fe and highest for B, alkalis and alkaline earths. To find out the solid phases controlling the solution concentration, the run of the concentrations of some elements is compared with the solubility data of their pure solid phases (e.g. hydroxides) from literature. It was found that the concentrations of Nd, Th and U in dependence on pH agree quite well with solubility data of AmOHCO3, ThO2/Th(OH)4 and Schoepite UO2·(OH)2) ·H2O. Therefore, it can be assumed that the maximum attainable concentrations of many elements are controlled by such pure solid phases.
Leaching and migration of Np, Pu, and Am from α-doped SON68 HLW glass in contact with dense clay
Authors: Valcke Elie , Gysemans Mireille , Moors Hugo , Van Iseghem Pierre , Godon Nicole , Jollivet Patrick
Published: April 2011

In the frame of an integrated in situ test on the alteration of the SON68 reference glass in realistic disposal conditions, the leaching of Np, Pu, and Am from α-doped SON68 glass samples and their migration in three clay-based backfill materials at high density was measured. The addition of powdered glass frit to a Ca-bentonite decreased the glass alteration by two orders of magnitude, and resulted in a concomitant decrease of the radionuclide leaching in comparison with dried Boom Clay, which is the more agressive backfill. All actinides were selectively retained in the alteration layer, but the retention degree was lower for Np than for Pu and Am. All backfill materials proved to be efficient barriers against radionuclide migration. For nearly all radionuclides and backfill materials, the migration profile showed a contribution of colloidal transport.
Son68 Glass Dissolution Kinetics at High Reaction Progress: Mechanisms Accounting for The Residual Alteration Rate
Authors: Frugier P. , Gin S. , Lartigue J.E. , Deloule E.
Published: April 2011

In a highly confined medium corresponding to geological repository conditions, the alteration rate of the French SON68 inactive nuclear reference glass drops by about four orders of magnitude below the initial rate. However, extended experiments lasting months or years provide evidence of a virtually constant or slowly decreasing residual alteration rate. Although very low, this rate could account for most of the altered glass thickness after 10 000 years. Experiments at high temperatures and especially high glass-surface-area-to-solution-volume ratios were performed to reveal and quantify the predominant mechanisms underlying the residual rate. The authors describe the characterization of the solution chemistry, the crystallized secondary phases, and the amorphous gel observed after alteration of the French SON68 inactive reference glass, and discuss their implications in terms of long-term behavior modeling. A slow diffusion mechanism is identified in the solid, involving alkalis in particular but also boron. This mechanism results in higher concentrations in solution that affect the system chemistry, not only by slightly modifying the pH and element speciation in solution (e.g. silicon), but also by inducing the precipitation of new crystallized secondary phases that can consume glass constituent elements in the same way as simple solution renewal. Diffusion and the precipitation of secondary phases are two mechanisms to be considered to account for the residual rate.
Pulsed Laser Deposition of Chromium Oxides: Substrate Effects
Authors: Jalili Helia , Heinig Nina , Leung K. T.
Published: April 2011

Pulsed Laser Deposition (PLD) was used to grow chromium oxides (CrOx) on MgO(100), Al2O3(0001), SrTiO3(100), LaAlO3(100), and Si(100) under different growth conditions, including substrate temperature, O2 pressure, and laser fluence. SEM, AFM and XRD measurements show that various phases of CrOx films with different morphologies could be obtained on different substrates under the same growth conditions. Half-metallic CrO2 needle-like nanostructured films were only observed on MgO(100) under a special set of conditions.
Magnetization, Magnetotransport and Ferromagnetic Resonance in A Permalloy Antidot Array with Square Holes
Authors: Yu Minghui , Malkinski Leszek , Spinu Leonard , Zhou Weilie
Published: April 2011

A Permalloy antidot array with square hole size 800?800 nm2 has been fabricated by the means of electron-beam lithography and lift-off techniques. An out-of-plane anisotropy was found in both the reference film of Permalloy and the antidot array with the thickness of 100 nm. Inhomogeneous current-density distribution and complex domain structures in the antidot nanostructure result in unique behavior of the magnetoresistance. Quantized standing spin-wave modes originating from the lateral confinement of the antidot nanostructure were clearly observed for the magnetic field applied normal to the array plane. Two uniform precession resonance modes occurred when the field deviated more than 30 degrees from the normal to the plane. These two resonances originate from different regions of the array having distinct dipolar field patterns with different orientation and magnitude of magnetostatic field. The easy axes of the anisotropy in these regions are in-plane and orthogonal to each other.
Analysis of Electrodeposited NiFe Thin Films for the Development of Planar Fluxgate Magnetic Sensors
Authors: dos Santos Thais Cavalheri , Mulato Marcelo
Published: April 2011

Nife alloys are potential candidates for the development of planar fluxgate magnetic microsensors. In this work, electrodeposition was used to produce NiFe thin films on top of copper substrates. When using this technique the variation of the electric potential, and thus the current density, alters the final stoichiometry of the deposited films, while the final thickness is determined by the total deposition time. We used current densities varying from 4.0 mA/cm2 to 28 mA/cm2, with steps of 4.0 mA/cm2. For each current density, total deposition times of 10, 20, 30 and 40 minutes were used. The morphology was characterized using scanning electron microscopy, structure was characterized using X-ray diffraction experiments, and the composition of the films were determined using energy dispersive spectroscopy. The magnetic properties were investigated evaluating the materials hysteresis cycle. The materials were optimized aiming for lowest coercivity values, and the final result was about 0.215 kA/m.
Preparation of Magnetite Nanoparticles by Thermal Decomposition of Hematite Powder in the Presence of Organic Solvent
Authors: Lin Chun-Rong , Chiang Ray-Kuang , Chen Chih-Jung , Lai Hsin-Yi , Lyubutin Igor S. , Alkaev Egor A.
Published: April 2011

Magnetite nanoparticles have been synthesized by thermal decomposition of hematite (Fe2O3) powder in the presence of high boiling point solvent. The mixture of hematite and 1- octadecene solvent was heated and stirred in nitrogen gas at the temperature of 320 °C for the desired time (∼2 to 28 hrs). The influence of the reaction time on transformation process was analyzed with X-ray diffraction (XRD), Mössbauer spectroscopy (MS), and magnetic measurements. XRD patterns show that the phase of intermediate was composed of spinel phase and corundum phase (α-Fe2O3). The 57Fe Mössbauer spectra show that the spinel phase originated from the magnetite particles. The structure transformation proportion of hematite to magnetite strongly depends on reaction times. After reflux for 28 hrs the hematite-magnetite transformation was complete. The mean crystallite size of pure phase of magnetite particles is about 40 nm. The saturation magnetization increases with the reaction time, which corresponds to an increase of concentration of magnetite in the samples. A pronounced feature of the Hc and σr/σs observed in samples is the steplike change which appears at 125 K and is characteristic of the Verwey transition. The hyperfine parameters of Mössbauer spectrum measured at low temperature also indicate that the Verwey phase transition occurs. In other words, the Verwey transition is an indication that the magnetite particles exactly grew up in the synthesized compounds. This thermal decomposition process provided a method to prepare pure magnetite as well as magnetite/hematite nanocomposites useful for various magnetic applications.
Competitive Ability of Black Henbane (Hyoscyamus niger) When Grown with Three Native Grasses
Authors: LaFantasie Jordana J. , Enloe Stephen F.
Published: April 2011

Black henbane is a poisonous, invasive plant in the family Solanaceae, and is typically associated with highly disturbed environments, such as pipelines, roadsides, and mammalian burrows. Often, such disturbances require reseeding for successful restoration; thus, the potential exists for competition between henbane and perennial grasses commonly used in restoration projects. These competitive interactions have not, to our knowledge, been evaluated. We conducted a greenhouse study to compare the response of henbane when grown alone and in combination with three common, cool season, perennial, northern mixed prairie grass species. We examined both seedling and mature grass response to the presence or absence of henbane and the response of henbane to the grasses. Using the relative neighbor-effect index, black henbane was found to be a very poor competitor with mature grasses and two out of three seedling grasses tested. All measures of henbane growth were significantly lower among plants grown with a mature grass pot companion. Total biomass of henbane was up to 99% lower when grown with mature grasses. Mature grasses were not negatively affected when grown in combination with henbane. Western wheatgrass (Pascopyrum smithii) was the only seedling grass that was competitive with henbane but was also the only seedling grass negatively affected by henbane in both biomass and tiller production. These experiments suggest that henbane is not well suited for invasion of mature grass stands but may negatively influence some perennial grass seedlings in restoration situations.
An Argument for the Universal Prophylaxis of Hepatitis B Infection in Patients Receiving Rituximab: A 7-Year Institutional Experience of Hepatitis Screening
Authors: Leung Christopher , Tsoi Edward , Burns Gareth , Sievert William
Published: April 2011

Reactivation of hepatitis B virus (HBV) replication in patients receiving rituximab is well described. Current international guidelines recommend HBV screening prior to the commencement of immunosuppressive therapy. However, adherence to such protocols has not previously been studied. We therefore audited screening practices and clinical outcomes in patients prescribed rituximab since its introduction in a large metropolitan health service. All patients receiving rituximab over an 88-month period were identified via pharmacy records. Medical records and laboratory results were reviewed to determine the timing and type of hepatitis screening. HBV flares were identified and correlated with clinical outcomes and any screening or prophylaxis given. Rituximab was given to 355 patients over 88 months (average age, 61 years; 51% male, 48% born overseas); 83% received rituximab for treatment of a hematological malignancy. HBV screening occurred in 31% of patients and, of these, 66% had pre-emptive screening. Five patients given cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab experienced HBV flares. Four died from viral reactivation. None received antiviral prophylaxis. Hepatitis screening rates in patients receiving rituximab in this study were lower than recommended in clinical guidelines. The identification of five patients with clinically important flares and four deaths in this group highlight the critical need to identify at-risk patients and provide timely prophylactic antiviral therapy to prevent serious morbidity and mortality. Even those with evidence of HBV seroconversion are at risk for fatal flares without active prophylactic antiviral therapy.
Uganda's Universal Secondary Education Policy and its Effect on ‘Empowered’ Women: How Reduced Income and Moonlighting Activities Differentially Impact Male and Female Teachers
Authors: Molyneaux Kristen J.
Published: April 2011

In January 2007 Uganda embarked on a strategy to implement a nationwide Universal Secondary Education (USE) policy. This article investigates how gender differences in Uganda's informal and formal teaching markets, that went unexamined during the implementation process of USE, differentially affected male and female teachers' incomes. In particular, this article examines the myriad ways in which male and female teachers are coping with reduced income, and questions ‘empowerment’ policies intended to expand educational opportunities for the masses but simultaneously refuse to engage with gendered differences within the educational work space.
Activin A Levels Are Associated With Abnormal Glucose Regulation in Patients With Myocardial Infarction
Authors: Andersen Geir Ø. , Ueland Thor , Knudsen Eva C. , Scholz Hanne , Yndestad Arne , Sahraoui Afaf , Smith Camilla , Lekva Tove , Otterdal Kari , Halvorsen Bente , Seljeflot Ingebjørg , Aukrust Pål
Published: April 2011

OBJECTIVE

On the basis of the role of activin A in inflammation, atherogenesis, and glucose homeostasis, we investigated whether activin A could be related to glucometabolic abnormalities in patients with acute myocardial infarction (MI).

RESEARCH DESIGN AND METHODS

Activin A measurement and oral glucose tolerance tests (OGTTs) were performed in patients (n = 115) with acute MI, without previously known diabetes, and repeated after 3 months. Release of activin A and potential anti-inflammatory effects of activin A were measured in human endothelial cells. Activin A effects on insulin secretion and inflammation were tested in human pancreatic islet cells.

RESULTS

1) In patients with acute MI, serum levels of activin A were significantly higher in those with abnormal glucose regulation (AGR) compared with those with normal glucose regulation. Activin A levels were associated with the presence of AGR 3 months later (adjusted odds ratio 5.1 [95% CI 1.73–15.17], P = 0.003). 2) In endothelial cells, glucose enhanced the release of activin A, whereas activin A attenuated the release of interleukin (IL)-8 and enhanced the mRNA levels of the antioxidant metallothionein. 3) In islet cells, activin A attenuated the suppressive effect of inflammatory cytokines on insulin release, counteracted the ability of these inflammatory cytokines to induce mRNA expression of IL-8, and induced the expression of transforming growth factor-β.

CONCLUSIONS

We found a significant association between activin A and newly detected AGR in patients with acute MI. Our in vitro findings suggest that this association represents a counteracting mechanism to protect against inflammation, hyperglycemia, and oxidative stress.
Competing Demands for Time and Self-Care Behaviors, Processes of Care, and Intermediate Outcomes Among People With Diabetes
Authors: McEwen Laura N. , Kim Catherine , Ettner Susan L. , Herman William H. , Karter Andrew J. , Beckles Gloria L. , Brown Arleen F.
Published: April 2011

OBJECTIVE

To determine whether competing demands for time affect diabetes self-care behaviors, processes of care, and intermediate outcomes.

RESEARCH DESIGN AND METHODS

We used survey and medical record data from 5,478 participants in Translating Research Into Action for Diabetes (TRIAD) and hierarchical regression models to examine the cross-sectional associations between competing demands for time and diabetes outcomes, including self-management, processes of care, and intermediate health outcomes.

RESULTS

Fifty-two percent of participants reported no competing demands, 7% reported caregiving responsibilities only, 36% reported employment responsibilities only, and 6% reported both caregiving and employment responsibilities. For both women and men, employment responsibilities (with or without caregiving responsibilities) were associated with lower rates of diabetes self-care behaviors, worse processes of care, and, in men, worse HbA1c.

CONCLUSIONS

Accommodations for competing demands for time may promote self-management and improve the processes and outcomes of care for employed adults with diabetes.
Sitting Time and Waist Circumference Are Associated With Glycemia in U.K. South Asians
Authors: Gill Jason M.R. , Bhopal Raj , Douglas Anne , Wallia Sunita , Bhopal Ruby , Sheikh Aziz , Forbes John F. , McKnight John , Sattar Naveed , Murray Gordon , Lean Michael E.J. , Wild Sarah H.
Published: April 2011

OBJECTIVE

To investigate the independent contributions of waist circumference, physical activity, and sedentary behavior on glycemia in South Asians living in Scotland.

RESEARCH DESIGN AND METHODS

Participants were 1,228 (523 men and 705 women) adults of Indian or Pakistani origin screened for the Prevention of Type 2 Diabetes and Obesity in South Asians (PODOSA) trial. All undertook an oral glucose tolerance test, had physical activity and sitting time assessed by International Physical Activity Questionnaire, and had waist circumference measured.

RESULTS

Mean ± SD age and waist circumference were 49.8 ± 10.1 years and 99.2 ± 10.2 cm, respectively. One hundred ninety-one participants had impaired fasting glycemia or impaired glucose tolerance, and 97 had possible type 2 diabetes. In multivariate regression analysis, age (0.012 mmol ⋅ L−1 ⋅ year−1 [95% CI 0.006–0.017]) and waist circumference (0.018 mmol ⋅ L−1 ⋅ cm−1 [0.012–0.024]) were significantly independently associated with fasting glucose concentration, and age (0.032 mmol ⋅ L−1 ⋅ year−1 [0.016–0.049]), waist (0.057 mmol ⋅ L−1 ⋅ cm−1 [0.040–0.074]), and sitting time (0.097 mmol ⋅ L−1 ⋅ h−1 ⋅ day−1 [0.036–0.158]) were significantly independently associated with 2-h glucose concentration. Vigorous activity time had a borderline significant association with 2-h glucose concentration (−0.819 mmol ⋅ L−1 ⋅ h−1 ⋅ day−1 [−1.672 to 0.034]) in the multivariate model.

CONCLUSIONS

These data highlight an important relationship between sitting time and 2-h glucose levels in U.K. South Asians, independent of physical activity and waist circumference. Although the data are cross-sectional and thus do not permit firm conclusions about causality to be drawn, the results suggest that further study investigating the effects of sitting time on glycemia and other aspects of metabolic risk in South Asian populations is warranted.
On the applicability of in situ soil probings to geological analyses
Authors: Radaszewski Robert , Wierzbicki Jędrzej
Published: April 2011

On the applicability of in situ soil probings to geological analyses

Examples of geoengineering methods (static and dynamic probings) that can be applied to analyses of geological environments are presented. The potential is shown by the results of the determination of the values of the soil-density index (ID), the soil-behaviour index (Ic), the constrained modulus (M), the overconsolidation ratio (OCR) and their vertical changes. The values obtained for ID and Ic facilitate the determination of layers with a specific character. This is demonstrated for several aeolian and glacial deposits in Poland. The application of static probings to the analyses of changes in OCR and M made it possible to identify several depositional phases and the effect of postdepositional processes. Usages of the probings can significantly contribute to the interpretation of palaeo-environments (e.g. in the context of geostatistical models), but the results obtained should be handled cautiously.
Términos de género natural e identidades teóricas
Authors: Fernández Moreno Luis
Published: April 2011

Kripke afirma en Naming and Necessity que existen ciertas similitudes entre los nombres propios y los términos de género natural. Una de ellas radica en que ambos tipos de expresiones figuran en enunciados de identidad que, en caso de ser verdaderos, son necesarios a posteriori; en el caso de los términos de género natural Kripke denomina a estos enunciados “identidades teóricas”. Kripke sostiene que esta similitud se sigue de otra, consistente en que ambos tipos de expresiones son designadores rígidos. Mi objetivo en este artículo es alegar que, aunque cabe sostener que los términos de género natural son designadores rígidos, esta propiedad de los términos de género natural no permite justificar el rasgo de necesidad que Kripke atribuye a las identidades teóricas. A este respecto centraré mis consideraciones en un tipo de términos de género natural, los términos de sustancias químicas, a los que aludiré como “términos de sustancia”.
La filosofía de la ciencia y el lenguaje: relaciones cambiantes, alcances y límites
Authors: Lorenzano Pablo
Published: April 2011

Este trabajo consta de tres secciones. En la primera, se señalarán algunos de los principales desarrollos de la filosofía de la ciencia durante el siglo XX y lo que va del XXI, ubicándolos en el marco de ciertas transformaciones filosóficas más generales, conocidas con los nombres de “giro lingüistico” y “giro pragmático”, respectivamente. En la segunda, se matizará la conexión establecida, fundamentalmente a partir de la revisión de la obra de un autor “clásico” como Carnap. Por último, se intentará realizar una suerte de “balance y perspectivas futuras”.
Otto Neurath: lenguaje, ciencia y valores. La incidencia de lo político
Authors: Gómez Ricardo J.
Published: April 2011

El proyecto de Neurath incluyó centralmente la tesis de la ciencia unificada por su funcionalidad para la acción política en aras de una humanidad mejor. Esto era así, porque la ciencia unificada era el instrumento fundamental para adoptar una unidad de acción, y ésta, a su vez, requería de una comunicación fluida la cual dependía de una cierta unidad del lenguaje de la ciencia. El resultado fue el convencionalismo radical anti-fundacional de Neurath de acuerdo al cual los científicos deben tomar decisiones para adoptar objetivos, instrumentos para alcanzarlos e, incluso, para aceptar/rechazar hipótesis y enciclopedias. Dichas decisiones involucran necesariamente la presencia de “motivos auxiliares” como utilidad, la felicidad humana, mejorar la situación del proletariado, entre otros. En consecuencia, hay una fuerte interrelación entre ciencia y política, porque la primera es un instrumento fundamental para alcanzar exitosamente metas políticas y, principalmente, porque los motivos políticos pueden jugar un rol crucial en las decisiones de aceptación científica.
De metáforas durmientes, endurecidas y nómades: un enfoque lingüistico de las metáforas en la comunicación de la ciencia
Authors: Ciapuscio Guiomar Elena
Published: April 2011

A partir de los trabajos fundacionales de Lakoff y Johnson (1991, 1999) existe un consenso generalizado entre lingüistas y filósofos respecto de la omnipresencia de las metáforas en la comunicación cotidiana. Sin embargo, es sabido que su ocurrencia y sus efectos en los textos de la ciencia han sido por largo tiempo temas controvertidos y polémicos; sólo recientemente se ha comenzado a trabajar de manera intensiva en la descripción y explicación de la naturaleza y las funciones que cumplen las metáforas en la comunicación de ciencia. En este artículo, intento aportar argumentos para fundamentar la pertinencia y la relevancia del enfoque lingüistico en este campo de investigación. El trabajo, que se basa en muestras de textos provenientes de distintas disciplinas y géneros discursivos, examina y explica el carácter asiduo y multifuncional del instrumento metafórico en los distintos escenarios considerados, y su valor como recurso de recontextualización.
Argumentación retórica y controversias: un estudio de caso
Authors: Regner Anna Carolina
Published: April 2011

Charles Darwin y George Mivart se envolvieron una vez en una famosa polémica en relación al origen de las especies. Analizaré esta polémica bajo el marco conceptual y las estrategias argumentativas de Darwin en Origin of Species (1872) y de Mivart en On the Genesis of Species (1871). Para entender la naturaleza de su polémica, compararé los problemas que se propusieron tratar, sus respuestas, así como también sus motivaciones, presuposiciones, argumentos y estrategias argumentativas. En detalle, me centraré en las objeciones de Mivart y en las respuestas de Darwin como parte de sus estrategias argumentativas. Trataré la refutación en su más amplio sentido (sin reducirlo a la mera prueba de su falsedad) como una colección de procedimientos para desafiar una posición o propuesta del oponente.
Editoriales conflictivas y disidentes en tiempos de dictadura (1966-1975)
Authors: Martínez Jesús A.
Published: April 2011

Sobre la base de una rica e inédita documentación del Archivo del Instituto Nacional del Libro Español y en concreto los expedientes del Registro de Empresas Editoriales, se estudian aquellas editoriales consideradas más conflictivas y disidentes por la Dictadura de Franco entre 1966 y 1975. A través de los planes editoriales, financieros, la documentación notarial, administrativa... y sobre todo de los informes policiales se desvelan las estrategias seguidas por las editoriales para superar los obstáculos del régimen y al mismo tiempo la aplicación de los mecanismo de control puestos en marcha por la ley de Prensa e Imprenta de 1966, que ponen de manifiesto el desfase entre una aparente tolerancia política y la mayor exigencia de los instrumentos de control de la cultura impresa. Las editoriales conflictivas y disidentes demostraron las contradicciones entre las transformaciones sociales, económicas y culturales de la España de los años sesenta y setenta y el inmovilismo político de la Dictadura.
Management of Demented Patients in Emergency Department
Authors: Valeriani Lavinia
Published: April 2011

The hospitalization of the elderly with acute illness is one of the most discussed in the organization of health services, it is not yet clear whether the hospital is really the best response to the needs of the elderly, especially those with cognitive impairment. Despite evidence of possible adverse effects of hospitalization (immobilization, acute confusional state resulting in sedation, risk of falls, intestinal sub‐ileus), there has been an increasing use of the hospital, particularly to specialist services. Regardless of the benefits from the shelter (instrumental diagnosis and prompt treatment of acute somatic disease), in people with dementia it needs to identify the characteristics of the person (cognitive impairment, functional status, somatic comorbidity, social and familial status), the personal needs and, therefore, diagnostic and therapeutic targets which must be assumed for that sick person during hospitalization. To this end, it is fundamental the role of assessment and diagnostic orientation that takes place in the Department of Emergency and Acceptance (DEA), which mainly receives patients at the hospital. Even before the hospital recovery it is therefore essential to check how many elderly patients with cognitive impairment that belong to the DEA, and what are their needs.
Pure Red Cell Aplasia and Associated Thymoma
Authors: Rosu Cristian , Cohen Sandra , Meunier Caroline , Ouellette Denise , Beauchamp Gilles , Rakovich George
Published: April 2011

Pure red cell aplasia is a rare cause of anemia, caused by an absence of red blood cell precursors in the bone marrow. It is usually a paraneoplastic syndrome, associated most commonly with large-cell granular lymphocyte leukemia but also thymoma. For patients who present both pure red cell aplasia and thymoma, thymectomy leads to an initial remission of the aplasia in 30% of cases. However, sustained remission may require the addition of medications such as corticosteroids, cyclospo­rine, or cyclophosphamide. We present a case of pure red cell aplasia associated with a thymoma in an otherwise healthy 80 year-old woman.
An improved method of determining ethanol use in a chronic pain population
Authors: Crews, PhD Bridgit , West, MS Robert , Gutierrez, CLS Ronita , Latyshev, MS Sergey , Mikel, PhD Charles , Almazan, CLS, MT (ASCP) Perla , Pesce, PhD, DABCC Amadeo , West, PhD Cameron , Rosenthal, DO, FAPA Murray
Published: April 2011

Background: Determination of ethanol use in the pain patient population being treated with chronic opioid therapy is critically important to the treating physician. Urinary ethanol, ethyl glucuronide (EtG), and ethyl sulfate (EtS) have been used to identify alcohol use. Because urine samples are shipped to reference laboratories, the possibility of glucose fermentation during transit producing ethanol complicates interpretation. The purpose of this study was to establish whether ethanol-positive urine samples were due to ingestion or fermentation during shipping.Methods: The authors obtained 94 ethanol-positive urine samples from pain patients, which were further tested for EtG, EtS, and glucose.Results: Only 62 of the 94 samples contained EtS or EtS. Of the 94 samples, 63 samples had glucose values above 10 mg/dL. Four of the 32 EtG-negative patients had ethanol levels that were nonphysiologic. Limitations of the study include the lack of demographic data beyond treatment with opioids for chronic pain.Conclusions: Roughly one-third of the time, ethanol-positive urine samples that have been shipped were positive because of fermentation and not because of patient alcohol consumption. This method is a combination of urinary ethanol measurement and liquid chromatography tandem mass spectrometry quantitation of both EtG and EtS. In the absence of these metabolites, the presence of urinary ethanol is attributed to fermentation. The improvement is a better definition of the source of the ethanol. Confirmatory testing showing the presence of the ethanol metabolites EtG and EtS is needed to validate that the ethanol is due to consumption. The presence of glucose, while common in the ethanol-positive samples, is not an absolute indicator that the ethanol was due to fermentation.
African biomass burning plumes over the Atlantic: aircraft based measurements and implications for H2SO4 and HNO3 mediated smoke particle activation
Authors: Fiedler V. , Arnold F. , Ludmann S. , Minikin A. , Hamburger T. , Pirjola L. , Dörnbrack A. , Schlager H.
Published: April 2011

Abstract. Airborne measurements of trace gases and aerosol particles have been made in two aged biomass burning (BB) plumes over the East Atlantic (Gulf of Guinea). The plumes originated from BB in the Southern-Hemisphere African savanna belt. On the day of our measurements (13 August 2006), the plumes had ages of about 10 days and were respectively located in the middle troposphere (MT) at 3900–5500 m altitude and in the upper troposphere (UT) at 10 800–11 200 m. Probably, the MT plume was lifted by dry convection and the UT plume was lifted by wet convection. In the more polluted MT-plume, numerous measured trace species had markedly elevated abundances, particularly SO2 (up to 1400 pmol mol−1), HNO3 (5000–8000 pmol mol−1) and smoke particles with diameters larger than 270 nm (up to 2000 cm−3). Our MT-plume measurements indicate that SO2 released by BB had not experienced significant loss by deposition and cloud processes but rather had experienced OH-induced conversion to gas-phase sulfuric acid. By contrast, a significant fraction of the released NOy had experienced loss, most likely as HNO3 by deposition. In the UT-plume, loss of NOy and SO2 was more pronounced compared to the MT-plume, probably due to cloud processes. Building on our measurements and accompanying model simulations, we have investigated trace gas transformations in the ageing and diluting plumes and their role in smoke particle processing and activation. Emphasis was placed upon the formation of sulfuric acid and ammonium nitrate, and their influence on the activation potential of smoke particles. Our model simulations reveal that, after 13 August, the lower plume traveled across the Atlantic and descended to 1300 m and hereafter ascended again. During the travel across the Atlantic, the soluble mass fraction of smoke particles and their mean diameter increased sufficiently to allow the processed smoke particles to act as water vapor condensation nuclei already at very low water vapor supersaturations of only about 0.04%. Thereby, aged smoke particles had developed a potential to act as water vapor condensation nuclei in the formation of maritime clouds.
Pseudo steady states of HONO measured in the nocturnal marine boundary layer: a conceptual model for HONO formation on aqueous surfaces
Authors: Wojtal P. , Halla J. D. , McLaren R.
Published: April 2011

Abstract. A complete understanding of the formation mechanism of nitrous acid (HONO) in the ambient atmosphere is complicated by a lack of understanding of processes occurring when aqueous water is present. We report nocturnal measurements of HONO, SO2 and NO2 by differential optical absorption spectroscopy over the ocean surface in a polluted marine environment. In this aqueous environment, we observed reproducible pseudo steady states (PSS) of HONO every night, that are fully formed shortly after sunset, much faster than seen in urban environments. During the PSS period, HONO is constant with time, independent of air mass source and independent of the concentration of NO2. The independence of HONO on the concentration of NO2 implies a 0° order formation process, likely on a saturated surface, with reversible partitioning of HONO to the gas phase, through vaporization and deposition to the surface. We observed median HONO/NO2 ratios starting at 0.13 at the beginning of the PSS period (with an apparent lower bound of 0.03), rising to median levels of ~0.30 at the end of the PSS period (with an upper bound >1.0). The implication of these numbers is that they suggest a common surface mechanism of HONO formation on terrestrial and aqueous surfaces, with an increase in the HONO/NO2 ratio with the amount of water available at the surface. The levels of HONO during the nocturnal PSS period are positively correlated with temperature, consistent with a partitioning of HONO from the surface to the gas phase with an apparent enthalpy of vaporization of ΔHSNL (HONO)=55.5±5.4 kJ mol−1. The formation mechanism on aqueous surfaces is independent of relative humidity (RH), despite observation of a negative HONO-RH correlation. A conceptual model for HONO formation on ambient aqueous surfaces is presented, with the main elements being the presence of a surface nanolayer (SNL), highly acidic and saturated with N(IV) precursors, production of HNO3, that diffuses to underlying water layers, and HONO, which partitions reversibly between the SNL and the gas phase. Implications of the conceptual model are discussed.
Precipitation forecasting through an analog sorting technique: a comparative study
Authors: Ben Daoud A. , Sauquet E. , Lang M. , Bontron G. , Obled C.
Published: April 2011

Abstract. This study aims at comparing two quantitative precipitation forecasting techniques based on the meteorological analogy concept. Method A considers first a selection of analogous situations at synoptic scale. Second a subset of the most similar situations in terms of hygrometry is extracted. Method B extends method A by two innovative ways, which are restricting the search for analogues with temperature information instead of the common season criterion, and exploiting the information about vertical motion considering vertical velocity. Forecasts are evaluated in a perfect prognosis context and in operational conditions as well, by mean of verification measures (Continuous Ranked Probability Skill Score and scores computed from contingency tables). Results of the case study in France show that: (1) there is an increase in forecast skill when temperature and vertical velocity are included in the procedure, (2) it is possible to anticipate rainfall events up to one week ahead and (3) the introduction of new variables such as vertical velocity may be useless beyond few days ahead if the forecast of the weather model is not reliable.
Status of satellite precipitation retrievals
Authors: Kidd C. , Levizzani V.
Published: April 2011

Abstract. Satellites offer an unrivalled vantage point to observe and measure Earth system processes and parameters. Precipitation (rain and snow) in particular, benefit from such observations since precipitation is spatially and temporally highly variable and with satellites overcoming some of the deficiencies of conventional gauge and radar measurements. This paper provides an overall review of quantitative precipitation estimation, covering the basis of the satellite systems used in the observation of precipitation, the dissemination and processing of this data, and the generation, availability and validation of these precipitation estimates. A selection of applications utilising these precipitation estimates are then outlined to exemplify the utility of such products.
Historical tsunami database for France and its overseas territories
Authors: Lambert J. , Terrier M.
Published: April 2011

Abstract. A search and analysis of a large number of historical documents has made it possible: (i) to discover so-far unknown tsunamis that have hit the French coasts during the last centuries, and (ii) conversely, to disprove the tsunami nature of several events referred to in recent catalogues. This information has been structured into a database and also made available as a website (http://www.tsunamis.fr) that is accessible in French, English and Spanish. So far 60 genuine ("true") tsunamis have been described (with their dates, causes, oceans/seas, places observed, number of waves, flood and ebb distances, run-up, and intensities) and referenced against contemporary sources. Digitized documents are accessible online. In addition, so as to avoid confusion, tsunamis revealed as "false" or "doubtful" have been compiled into a second catalogue. Both the database and the website are updated annually corresponding to the state of knowledge, so as to take into account newly discovered historical references and the occurrence of new tsunamis on the coasts of France and many of its overseas territories: Guadeloupe, Martinique, French Guiana, New Caledonia, Réunion, and Mayotte.
Intravitreal Bevacizumab in Central Retinal Vein Occlusion: 18-month Results of a Prospective Clinical Trial
Authors: Algvere Peep V. , Epstein David , von Wendt Gunvor , Seregard Stefan , Kvanta Anders
Published: April 2011

Purpose.

To evaluate the long-term visual results in central retinal vein occlusion (CRVO) following repeated intravitreal injections of bevacizumab (IVB).

Methods.

Thirteen patients (aged 34 to 79 years) with a duration of CRVO of 2 weeks to 6 months (mean 2.5 months) had a best-corrected visual acuity (BCVA) 0.05 to 0.4 (mean 0.13) as determined by Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Clinical examination was carried out at baseline and every 6 to 8 weeks. Intravitreal bevacizumab (1.25 mg) was given every 6 weeks during the first 6 months, and after that at the discretion of the attending physician.

Results.

In total, 96 IVB (average 7.4/patient) were given: 50 IVB during the first 6 months, 28 from 6 to 12 months, and 18 from 12 to 18 months. Average BCVA had improved 15 ETDRS letters at 3 months, 24 letters at 6 months, 24 letters at 12 months, and 18 letters at 18 months (p<0.05). Eight patients (62%) had gained >15 ETDRS letters at 12 months, and 7 subjects (54%) >15 ETDRS letters at 18 months. Foveal thickness decreased from 596 μm at baseline to 294 μm at 18 months (p<0.05) and mean IOP from 15.2 mmHg to 15.8 mmHg. No serious adverse events occurred.

Conclusions.

Following repeated IVB, there was a significant gain of BCVA during the follow-up of 18 months. To maintain visual gain, regular ophthalmologic examinations and repeated injections seem to be necessary as long as the disease is active.