bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of dry cryogenic treatment on Vickers hardness and wear resistance of new martensitic shape memory nickel-titanium alloy
Authors: Vinothkumar Thilla Sekar , Kandaswamy Deivanayagam , Prabhakaran Gopalakrishnan , Rajadurai Arunachalam
Published: April 2016

Objectives: The aim of this study is to investigate the role of dry cryogenic treatment (CT) temperature and time on the Vickers hardness and wear resistance of new martensitic shape memory (SM) nickel-titanium (NiTi) alloy. The null hypothesis tested was that there is no difference in Vickers hardness and wear resistance between SM NiTi alloys following CT under two soaking temperatures and times. Materials and Methods: The composition and the phase transformation behavior of the alloy were examined by X-ray energy dispersive spectroscopy and differential scanning calorimetry, respectively. Fifteen cylindrical specimens and 50 sheet specimens were subjected to different CT conditions: Deep cryogenic treatment (DCT) 24 group: −185°C, 24 h; DCT six group: −185°C, 6 h; shallow cryogenic treatment (SCT) 24 group: −80°C, 24 h; SCT six group: −80°C, 6 h; and control group. Wear resistance was assessed from weight loss before and after reciprocatory wet sliding wear. Results: The as-received SM NiTi alloy contained 50.8 wt% nickel and possessed austenite finish temperature (Af) of 45.76°C. Reduction in Vickers hardness of specimens in DCT 24 group was highly significant (P < 0.01; Tukey's honest significant difference [HSD]). The weight loss was significantly higher in DCT 24 group (P < 0.05; Tukey's HSD). Conclusion: Deep dry CT with 24 h soaking period significantly reduces the hardness and wear resistance of SM NiTi alloy.
Bounded cohomology with coefficients in uniformly convex Banach spaces
Authors: Bestvina Mladen , Bromberg Kenneth , Fujiwara Koji
Published: April 2016

We show that for acylindrically hyperbolic groups

\Gamma

(with no nontrivial finite normal subgroups) and arbitrary unitary representation

\rho

of

\Gamma

in a (nonzero) uniformly convex Banach space the vector space

H^2_b(\Gamma;\rho)

is infinite dimensional. The result was known for the regular representations on

\ell^p(\Gamma)

with

1 < p < \infty

by a different argument. But our result is new even for a non-abelian free group in this great generality for representations, and also the case for acylindrically hyperbolic groups follows as an application.
Quadratic differentials, half-plane structures, and harmonic maps to trees
Authors: Gupta Subhojoy , Wolf Michael
Published: April 2016

Let

(\Sigma,p)

be a pointed Riemann surface and

k\geq 1

an integer. We parametrize the space of meromorphic quadratic differentials on

\Sigma

with a pole of order

k+2

at

p

, having a connected critical graph and an induced metric composed of

k

Euclidean half-planes. The parameters form a finite-dimensional space

\mathcal{L} \cong \mathbb{R}^{k} \times S^1

that describe a model singular-flat metric around the puncture with respect to a choice of coordinate chart. This generalizes an important theorem of Strebel, and associates, to each point in

\mathcal{T}_{g,1} \times \mathcal{L}

, a unique metric spine of the surface that is a ribbon-graph with

k

infinite-length edges to

p

. The proofs study and relate the singular-flat geometry of the quadratic differential, and the infinite-energy harmonic map from

\Sigma \setminus p

to a

k

-pronged tree, having the same Hopf differential.
Explicit Methods in Number Theory
Authors: Belabas Karim , Poonen Bjorn , Rodriguez Villegas Fernando
Published: April 2016

The aim of the series of Oberwolfach meetings on ‘Explicit methods in number theory’ is to bring together people attacking key problems in number theory via techniques involving concrete or computable descriptions. Here, number theory is interpreted broadly, including algebraic and analytic number theory, Galois theory and inverse Galois problems, arithmetic of curves and higher-dimensional varieties, zeta and

L

-functions and their special values, and modular forms and functions.
Measurement of Clinical Pharmacy Key Performance Indicators to Focus and Improve Your Hospital Pharmacy Practice
Authors: Lo Elaine , Rainkie Daniel , Semchuk William M , Gorman Sean K , Toombs Kent , Slavik Richard S , Forbes David , Meade Andrea , Fernandes Olavo , Spina Sean P
Published: April 2016

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Hospital Pharmacy in Belgium: From Moving Boxes to Providing Optimal Therapy
Authors: De Rijdt Thomas , Desplenter Franciska
Published: April 2016

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Should Developed Countries, Including Canada, Provide Universal Access to Essential Medications through a National, Publicly Funded and Administered Insurance Plan?
Authors: Minhas Rajwant , Ng Joan Chung Yan , Tan Jason , Wu Hilary , Stabler Sarah , Beach Jessica , Collins Kyle , Peterson Shaylee , Shah Kieran , Louie Sam
Published: April 2016

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Amélioration de la sécurité d’une pompe de pharmacie par l’utilisation d’une imprimante 3D
Authors: Forest Jean-Marc , Boyajian Robert , Gagné-Laverdière Gabriel , Lebel Denis
Published: April 2016

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Asymmetries of Knowledge: Mediated Ethnography and ICT for Development
Authors: Jensen Casper Bruun
Published: April 2016

Over the last few decades the Internet, World Wide Web, cyberspace and so forth have emerged as crucial cultural and political arenas, and thus of increasing relevance as objects and areas of ethnographic inquiry. The paper argues that the ethnographical entry-point for studying such technologically mediated arenas creates specific effects of ‘path-dependence ‘and attendant asymmetries of knowledge. Globally distributed networks of organizations, collaborating on issues relating to information- and communication technologies for development (ICT4Dev) provides context for the argument. Three sources of knowledge asymmetries are identified: limited presence, partial information and uncertain connections. Athough mediated ethnographies invariably create asymmetries of knowledge they also thrive on these asymmetries. This is because they also replicate features of the field itself: asymmetries of knowledge likewise characterize and influence the activities of globally distributed networks. In conjunction, the three sources of asymmetry create a predicament of mutual opacity as a condition of knowledge making in ICT4Dev networks as well as for the ethnographer. Focusing on the consequences of these asymmetries, the paper argues that mediated ethnography has central contributions to make in a) analyzing the specific formats of the social that emerges from globally distributed organizations and networks and b) bringing to light some alternative stories about what might be done with ICT4Dev.
Survey Methods for Hard-to-Reach Populations: Introduction to the Special Issue
Authors: Marpsat Maryse , Razafindratsima Nicolas
Published: April 2016

Surveys of hard to reach populations (rare, no known sampling frames) have been, for some years, the object of methodological reflection. Various methods aiming at the production of an ‘extrapolable’ sample of these populations have been proposed: time-space sampling (TSS) or time-location sampling (TLS), respondent driven sampling (RDS), or the ‘capture - recapture’ method. After defining what a hard-to reach-population is, this article provides an outline of these various approaches before going on to briefly consider the papers contained in this special issue.
Conception, échantillonnage, organisation du terrain d'une enquête TLS et nouveaux développements: Coquelicot, une enquête auprès d'usagers de drogues
Authors: Jauffret-Roustide Marie , Le Strat Yann
Published: April 2016

Afin de suivre la dynamique de l’épidémie d'hépatite C chez les usagers de drogue (UD) en France, l'enquête ANRS-Coquelicot a été réalisée en France entre 2004 et 2007. Cette enquête menée sur 5 villes (Lille, Strasbourg, Paris, Bordeaux, Marseille) est constituée d'un volet épidémiologique et socio-anthropologique. La population cible de cette enquête est à la fois difficile à définir et à atteindre, en raison de profils sociaux et de rapports à l'usage de drogues diversifiés et de la stigmatisation de la pratique d'usage. La population des UD étudiée est celle qui fréquente les dispositifs spécialisés et qui représente une sous-population ayant un « rapport problématique aux drogues » et plutôt socialement précaire. La méthodologie utilisée dans le volet épidémiologique a mis en œuvre une stratégie d’échantillonnage aléatoire via un plan de sondage, intégrant la Méthode Généralisée du Partage des Poids (MGPP) et s'appuie sur un recueil de données biologiques pour estimer la prévalence de l'hépatite C. L'utilisation d'outils méthodologiques innovants utilisés pour la première fois en France (plan de sondage avec MGPP, tests biologiques) dans l'enquête ANRS-Coquelicot a permis de produire des estimations valides de la prévalence du VHC dans la population des UD, prévalence particulièrement élevée qui se monte à 60%. La méthodologie mise en œuvre dans cette enquête a permis d'inférer ses résultats à la population cible étudiée. L’épidémiologie a permis de décrire, de mesurer et d'accéder dans une certaine mesure à la généralisation. Les données qualitatives (entretiens et observations ethnographiques) ont été confrontées aux données produites par l’épidémiologie et ont permis de mieux appréhender le contexte social du risque et le sens que les UD lui accordent. L'utilisation de méthodologies quantitatives et qualitatives a ainsi permis d'aborder la question de l'exposition au risque de l'hépatite C chez les usagers de drogues dans sa complexité.
Enquêtes quantitatives auprès des populations difficiles à joindre: L'expérience de l'Observatoire français des drogues et des toxicomanies
Authors: Cadet-Taïrou Agnès , Reynaud-Maurupt Catherine , Costes Jean-Michel , Palle Christophe
Published: April 2016

Cet article décrit la conception du dispositif de connaissance des pratiques de consommation de drogues chez des usagers dits « difficiles à joindre », mis en œuvre par l'Observatoire français des drogues et des toxicomanies (OFDT). L'OFDT a pour objectif de proposer une vision cohérente et précise des phénomènes d'usages de drogues et d'en suivre les évolutions dans une perspective nationale, en dépit des disparités régionales. Le champ d’étude a été segmenté en espaces d'usage, d'observation et/ou de contacts possibles avec les usagers de drogues. L'analyse au fil du temps de données quantitatives et qualitatives a permis de segmenter également l'ensemble théorique et hétérogène formé par les usagers de drogues (UD), en types de populations et en sous-populations. Celles-ci présentent des caractéristiques et adoptent des pratiques différentes, qui n’évoluent pas toujours de la même manière. Elles sont parfois géographiquement instables. L'expérience de l'OFDT concernant les études probabilistes menées auprès des UD ou de populations à forte prévalence d'usage de drogues est évoquée à travers une étude « capture-recapture » visant à estimer des prévalences d'usage problématique dans 6 agglomérations françaises et une enquête quantitative menée à partir d'un plan de sondage ethnographiquement raisonné en milieu festif orienté vers la musique « électro ». Ces études à échantillonnage complexe s'avèrent indispensables, notamment pour la mesure de prévalences d'usages de drogues au sein de populations non exclusivement composée d'UD. Cependant, il nous semble qu'elles ne peuvent assurer à elles seules, la mesure d'un phénomène ou le suivi de ses évolutions, du fait des nombreuses sources de biais attachées à l’échantillonnage et au recueil des données dans les enquêtes en population difficile à joindre. La mise en perspective de leurs résultats avec des données quantitatives issues d'autres sources, notamment les séries temporelles recueillies auprès des usagers des structures dédiées aux UD, mais également des données ethnographiques, nous apparaît indispensable au suivi des tendances.
The Impact of Research on Policy in the Drugs Field
Authors: MacGregor Susanne
Published: April 2016

The article uses examples of UK drugs research (1980–2010) to illustrate the complex relationship between research, policy and politics. It draws on literature, documentary analysis, interviews and participant observation. ‘Drugs' is a contested issue and values compete with evidence to influence decisions. Research provides only one form of evidence. Sociological research became less influential in these years, reflecting the neo-liberal climate. The absence of research was also influential in shaping policy. However social research made significant contributions. It impacted initially by helping to understand a new problem; then through the construction of the ‘harm reduction approach’; and then by contributing to ‘the criminalisation of drugs policy’. Research helped by gathering intelligence, accumulating findings, raising questions and encouraging a culture of objectivity. Cases described indicate the role of filters as evidence percolated into or was rejected by policy-making circles. As government advisors, researchers risked being captured by politicians. But engaging in public debate could be challenging as researchers might lose control over how their findings were interpreted. The media were dominant influences in public debate and the simplification of discourse at this level was a hindrance. It is concluded that research has had impact where it linked directly to the policy market. Networks, think-tanks and policy entrepreneurs played key roles. An appropriate packaging of findings was important. Impact happened where there was a receptive audience and a window of opportunity opened, raising the issue on policy agendas. To intervene effectively, researchers had to ensure that reports were timely, to act quickly and work in alliances. Researchers who had impact often had a specific commitment to the drugs field. Beyond this, there remains a need for humanities and social science scholars to engage in public dialogue on this issue.
Actor-Network Theory and Methodology: Social Research in a More-Than-Human World
Authors: Nimmo Richie
Published: April 2016

This article explores the methodological implications of actor-network theory for social research. Pointing to an increasing awareness of ANT in sociological discourse, but assuming that it is more widely known than well understood, the article outlines some of the key features of ANT as an approach to social life, before addressing the tricky question of how these ideas translate into methodological practice. The possibilities of the approach are illustrated by reference to the author's own ANT-inspired historical research on the socio-material history of dairy milk in the UK, which is used as a point of reference and an example throughout. Particular attention is given to the practical method deployed in the milk study, namely documentary historiography, leading to a critical exploration of the use of ANT in the analysis of historical texts. This involves considering the nature of the relationship between texts and lived practices, and drawing out how ANT offers a distinctive way of seeing texts which challenges the standard ethnographic view of texts and fundamentally transforms the issue. Given that documentary historiography is not a method strongly associated with actor-network theory because it raises considerable methodological dilemmas, this provides one particular account of how such dilemmas can be managed or overcome. Social researchers interested in the potential of actor-network theory should be able to draw upon this in exploring the possibilities of the approach for their own work.
Adding Time into the Mix: Stakeholder Ethics in Qualitative Longitudinal Research
Authors: Neale Bren
Published: April 2016

This paper explores the ethical considerations that arise in the conduct of Qualitative Longitudinal (QL) research, drawing on work undertaken as part of the ESRC Timescapes initiative. Adding time into the mix of a qualitative study heightens the need for ethical literacy. Well established ethical principles take on new meaning and need reworking when seen with a temporal gaze – for example, those relating to consent as an ongoing process; sustaining confidentiality when the risk of disclosure is magnified over time; and the ethical representation of lives in the construction, display and re-use of research data. The challenges are magnified in relation to the tenor, flux and recurrent nature of the research process. The elongated time frames for empirical research create long term, reciprocal research relationships that need careful consideration and nurturing over time.

More broadly, as QL research unfolds, a wider constituency of individuals and organisations become implicated in the process, necessitating new thinking about their varied needs and claims. QL researchers find themselves navigating through a broader ethical landscape, which this paper seeks to capture through the concept of ‘stakeholder’ ethics. A stakeholder approach allows for the varied needs of those implicated in the research to be recognised and reconciled, and for a greater appreciation of how research relationships intersect and impact on the research process as it unfolds. Adding time into the mix also enables a distinction to be drawn between pro-active and re-active ethical strategies, both of which are needed in the longer time frames of QL enquiry. The discussion focuses on the conduct of QL research, illustrating the practices of researchers in the field as a starting point for a productive iteration between ethical principles and practice. The paper concludes that time is a complicating factor but also an important resource in the ethical conduct of qualitative research.
Estimating the Risk of Domestic Water Source Contamination Following Precipitation Events
Authors: Eisenhauer Ian F. , Hoover Christopher M. , Remais Justin V. , Monaghan Andrew , Celada Marco , Carlton Elizabeth J.
Published: April 2016

Climate change is expected to increase precipitation extremes, threatening water quality. In low resource settings, it is unclear which water sources are most vulnerable to contamination following rainfall events. We evaluated the relationship between rainfall and drinking water quality in southwest Guatemala where heavy rainfall is frequent and access to safe water is limited. We surveyed 59 shallow household wells, measured precipitation, and calculated simple hydrological variables. We compared Escherichia coli concentration at wells where recent rainfall had occurred versus had not occurred, and evaluated variability in the association between rainfall and E. coli concentration under different conditions using interaction models. Rainfall in the past 24 hours was associated with greater E. coli concentrations, with the strongest association between rainfall and fecal contamination at wells where pigs were nearby. Because of the small sample size, these findings should be considered preliminary, but provide a model to evaluate vulnerability to climate change.
Urban Water Services in Fragile States: An Analysis of Drinking Water Sources and Quality in Port Harcourt, Nigeria, and Monrovia, Liberia
Authors: Kumpel Emily , Albert Jeff , Peletz Rachel , de Waal Dominick , Hirn Maximilian , Danilenko Alexander , Uhl Vincent , Daw Ashish , Khush Ranjiv
Published: April 2016

Establishing and maintaining public water services in fragile states is a significant development challenge. In anticipation of water infrastructure investments, this study compares drinking water sources and quality between Port Harcourt, Nigeria, and Monrovia, Liberia, two cities recovering from political and economic instability. In both cities, access to piped water is low, and residents rely on a range of other private and public water sources. In Port Harcourt, geographic points for sampling were randomly selected and stratified by population density, whereas in Monrovia, locations for sampling were selected from a current inventory of public water sources. In Port Harcourt, the sampling frame demonstrated extensive reliance on private boreholes and a preference, in both planned and unplanned settlements, for drinking bottled and sachet water. In Monrovia, sample collection focused on public sources (predominantly shallow dug wells). In Port Harcourt, fecal indicator bacteria (FIB) were detected in 25% of sources (N = 566), though concentrations were low. In Monrovia, 57% of sources contained FIB and 22% of sources had nitrate levels that exceeded standards (N = 204). In Monrovia, the convenience of piped water may promote acceptance of the associated water tariffs. However, in Port Harcourt, the high prevalence of self-supply and bottled and sachet drinking water suggests that the consumer's willingness to pay for ongoing municipal water supply improvements may be determined by service reliability and perceptions of water quality.
Individual- and Household-Level Risk Factors Associated with Malaria in Mutasa District, Zimbabwe: A Serial Cross-Sectional Study
Authors: Kanyangarara Mufaro , Mamini Edmore , Mharakurwa Sungano , Munyati Shungu , Gwanzura Lovemore , Kobayashi Tamaki , Shields Timothy , Mullany Luke C. , Mutambu Susan , Mason Peter R. , Curriero Frank C. , Moss William J.
Published: April 2016

Malaria constitutes a major public health problem in Zimbabwe, particularly in the north and east bordering Zambia and Mozambique. In Manicaland Province in eastern Zimbabwe, malaria transmission is seasonal and unstable. Over the past decade, Manicaland Province has reported increased malaria transmission due to limited funding, drug resistance and insecticide resistance. The aim of this study was to identify risk factors at the individual and household levels to better understand the epidemiology of malaria and guide malaria control strategies in eastern Zimbabwe. Between October 2012 and September 2014, individual demographic data and household characteristics were collected from cross-sectional surveys of 1,116 individuals residing in 316 households in Mutasa District, one of the worst affected districts. Factors associated with malaria, measured by rapid diagnostic test (RDT), were identified through multilevel logistic regression models. A total of 74 participants were RDT positive. Sleeping under a bed net had a protective effect against malaria despite pyrethroid resistance in the mosquito vector. Multivariate analysis showed that malaria risk was higher among individuals younger than 25 years, residing in households located at a lower household density and in closer proximity to the Mozambique border. The risk factors identified need to be considered in targeting malaria control interventions to reduce host–vector interactions.
High-Resolution Plasmodium falciparum Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control
Authors: Kanyangarara Mufaro , Mamini Edmore , Mharakurwa Sungano , Munyati Shungu , Gwanzura Lovemore , Kobayashi Tamaki , Shields Timothy , Mullany Luke C. , Mutambu Susan , Mason Peter R. , Curriero Frank C. , Moss William J.
Published: April 2016

In Zimbabwe, more than half of malaria cases are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. The objectives of this study were to develop a prediction model based on environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province. From October 2012 to September 2015, 483 households were surveyed, and 104 individuals residing within 69 households had positive rapid diagnostic test results. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates extracted from high-resolution remote sensing data sources. Model predictions and prediction standard errors were generated for the rainy and dry seasons. The resulting maps predicted elevated risk during the rainy season, particularly in low-lying areas bordering Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria risk scattered along the northern and western peripheries of the study area. These findings underscore the need for strong cross-border malaria control initiatives to complement country-specific interventions.
Scabies Among Elderly Korean Patients with Histories of Leprosy
Authors: Park Hyungcheol , Lee Chaeyoung , Park Seungkyu , Kwon Hyeon , Kweon Sun-Seog
Published: April 2016

A scabies epidemic, traced by the hospital-based surveillance system, was reported in a Korean leprosarium. A total of 200 symptomatic cases were found during 2012–2014 among 570 elderly former leprosy patients. Most of cases were classic type scabies (87%) and aged 75 years and older (72%). Surveillance system for early diagnosis and prompt intervention was applied and the scabies epidemic was controlled effectively in this long-term care facility.
A Clinical Study of Improved Nitrile Butadiene Rubber Soft Lining Material and Acrylic Denture Base
Authors: Bhandari Aruna Jawaharlal , Bhandari Akshay Jawaharlal
Published: April 2016

Relining of a complete denture essentially involves the recording of an impression within its support surface so as to correct the deficiency that has arisen as a result of tissues changes. Relining can be done simply, accurately and inexpensively by using lining material. In relining, a new thin layer of lining material is added to the existing denture base. Due to residual ridge resorption and irreversible changes in the tissues supporting, the prosthesis become loose and patient may complaint of frequent pain and ulceration. Relining can be done in such patients by using lining. A soft denture liner which is placed in a denture base that contacts tissues provides comfort. Resilient denture liners because of their viscoelastic properties act as shock absorber and reduce and distribute the stress on the denture bearing tissues. However, there is an increased probability of fungal growth on soft lining materials. Adherence of Candida to solid surface, such as denture resin or lining material has been thought to be the first step in successful colonization, subsequent plaque formation and development of pathogenesis. This study is done to find the adherence of Candida albicans to nitrile butadiene rubber (NBR) soft lining material and safe duration of its clinical usage.

How to cite this article

Bhandari AJ, Bhandari AJ. A Clinical Study of Improved Nitrile Butadiene Rubber Soft Lining Material and Acrylic Denture Base. Int J Prosthodont Restor Dent 2015;5(4):91-94.
Validation of satellite-based noontime UVI with NDACC ground-based instruments: influence of topography, environment and overpass time
Authors: Brogniez Colette , Auriol Frédérique , Deroo Christine , Arola Antti , Kujanpää Jukka , Sauvage Béatrice , Kalakoski Niilo , Pitkänen Mikko R. A. , Catalfamo Maxime , Metzger Jean-Marc , Tournois Guy , Da Conceicao Pierre
Published: April 2016

Abstract. Spectral solar UV radiation measurements are performed in France using three spectroradiometers located in very different sites. One is installed in Villeneuve d’Ascq, in the north of France (VDA). It is an urban site in a topographically flat region. Another instrument is installed in Observatoire de Haute Provence, in the French Southern Alps (OHP). It is a rural mountainous site. The third instrument is installed in Saint-Denis, Reunion Island (SDR). It is a coastal urban site on a small mountainous Island in the Southern tropics. The three instruments are affiliated to the Network for the Detection of Atmospheric Composition Change (NDACC) and carry out routine measurements to monitor the spectral solar UV radiation and enable derivation of UV index (UVI). The ground-based UVI values observed at solar noon are compared to similar quantities derived from OMI/Aura and GOME-2/Metop-A satellite measurements for validation of these satellite-based products. The present study concerns the period 2009–September 2012, date of the change of OMI data processing. UVI products from the old (v1.2) and new (v1.3) versions of OMI are used to assess the improvement of the new processing. On average, estimates from satellite instruments always overestimate surface UVI at solar noon. Under cloudless conditions the satellite-derived estimates of UVI compare satisfactorily with ground-based data: the median relative bias is less than 8 % at VDA and 4 % at SDR for both OMI-v1.3 and GOME-2, and about 6 % for OMI-v1.3 and 2% for GOME-2 at OHP. Correlation between satellite-based and ground-based data is better at VDA and OHP (about 0.99) than at SDR (0.96) for both spatial instruments. For all sky conditions the median relative biases are much larger, with large dispersion for both instruments at all sites (VDA: about 12 %; OHP: 9 %; SDR: 11 %). Correlation between satellite-based and ground-based data is still better at VDA and OHP (about 0.95) than at SDR (about 0.73) for both satellite instruments. These results are explained considering the time of overpass of the two satellites, which is far from solar noon, preventing a good estimation of the cloud cover necessary to a good modelling of the UVI. Site topography and environment are shown to have a non-significant influence. At VDA and OHP, OMI-v1.3 shows a significant improvement with respect to v1.2 that did not account for absorbing aerosols.
Interannual variability of the midsummer drought in Central America and the connection with sea surface temperatures
Authors: Maldonado Tito , Rutgersson Anna , Alfaro Eric , Amador Jorge , Claremar Björn
Published: April 2016

Abstract. The midsummer drought (MSD) in Central America is characterised in order to create annual indexes representing the timing of its phases (start, minimum and end), and other features relevant for MSD forecasting such as the intensity and the magnitude. The MSD intensity is defined as the minimum rainfall detected during the MSD, meanwhile the magnitude is the total precipitation divided by the total days between the start and end of the MSD. It is shown that the MSD extends along the Pacific coast, however, a similar MSD structure was detected also in two stations in the Caribbean side of Central America, located in Nicaragua. The MSD intensity and magnitude show a negative relationship with Niño 3.4 and a positive relationship with the Caribbean low-level jet (CLLJ) index, however for the Caribbean stations the results were not statistically significant, which is indicating that other processes might be modulating the precipitation during the MSD over the Caribbean coast. On the other hand, the temporal variables (start, minimum and end) show low and no significant correlations with the same indexes.The results from canonical correlation analysis (CCA) show good performance to study the MSD intensity and magnitude, however, for the temporal indexes the performance is not satisfactory due to the low skill to predict the MSD phases. Moreover, we find that CCA shows potential predictability of the MSD intensity and magnitude using sea surface temperatures (SST) with leading times of up to 3 months. Using CCA as diagnostic tool it is found that during June, an SST dipole pattern upon the neighbouring waters to Central America is the main variability mode controlling the inter-annual variability of the MSD features. However, there is also evidence that the regional waters are playing an important role in the annual modulation of the MSD features. The waters in the PDO vicinity might be also controlling the rainfall during the MSD, however, exerting an opposite effect at the north and south regions of Central America.
Validation and Analysis of MOPITT CO Observations of the Amazon Basin
Authors: Deeter M. N. , Martínez-Alonso S. , Gatti L. V. , Gloor M. , Miller J. B. , Domingues L. G. , Correia C. S. C.
Published: April 2016

Abstract. We analyze satellite retrievals of carbon monoxide from the MOPITT instrument over the Amazon Basin, focusing on the MOPITT Version 6 "multispectral" retrieval product (exploiting both thermal-infrared and near-infrared channels). Validation results based on in-situ vertical proﬁles measured between 2010 and 2013 are presented for four sites in the Amazon Basin. Results indicate a signiﬁcant negative bias in retrieved lower-tropospheric CO concentrations. The possible inﬂuence of smoke aerosol as a source of retrieval bias is investigated using collocated AERONET AOD measurements at two sites, but does not appear to be signiﬁcant. Finally, we exploit the MOPITT record to analyze both the mean annual cycle and the interannual variability of CO over the Amazon Basin since 2002.
Dead time effect on the Brewer measurements: correction and estimated uncertainties
Authors: Fountoulakis Ilias , Redondas Alberto , Bais Alkiviadis F. , Rodriguez-Franco Juan José , Fragkos Konstantinos , Cede Alexander
Published: April 2016

Abstract. Brewer spectrophotometers are widely used instruments which perform spectral measurements of the direct, the scattered and the global solar UV irradiance. By processing these measurements a variety of secondary products can be derived such as the total columns of ozone (TOC), sulfur dioxide and nitrogen dioxide and aerosol optical properties. Estimating and limiting the uncertainties of the final products is of critical importance. High-quality data have a lot of applications and can provide accurate estimations of trends.The dead time is specific for each instrument and improper correction of the raw data for its effect may lead to important errors in the final products. The dead time value may change with time and, with the currently used methodology, it cannot always be determined accurately. For specific cases, such as for low ozone slant columns and high intensities of the direct solar irradiance, the error in the retrieved TOC, due to a 10 ns change in the dead time from its value in use, is found to be up to 5 %. The error in the calculation of UV irradiance can be as high as 12 % near the maximum operational limit of light intensities. While in the existing documentation it is indicated that the dead time effects are important when the error in the used value is greater than 2 ns, we found that for single-monochromator Brewers a 2 ns error in the dead time may lead to errors above the limit of 1 % in the calculation of TOC; thus the tolerance limit should be lowered. A new routine for the determination of the dead time from direct solar irradiance measurements has been created and tested and a validation of the operational algorithm has been performed. Additionally, new methods for the estimation and the validation of the dead time have been developed and are analytically described. Therefore, the present study, in addition to highlighting the importance of the dead time for the processing of Brewer data sets, also provides useful information for their quality control and re-evaluation.
Influence of the melting temperature on the measurement of the mass concentration and size distribution of black carbon in snow
Authors: Kinase Takeshi , Kita Kazuyuki , Tsukagawa-Ogawa Yoshimi , Goto-Azuma Kumiko , Kawashima Hiroto
Published: April 2016

Abstract. The influence of temperature and time of snow sample melting on the measurement of mass concentration and size distribution of black carbon (BC) in snow was evaluated experimentally. In the experiments, fresh (Shirouma) and aged (Hakusan) snow samples were melted at different temperatures or at different time lengths, and the BC mass concentration and size distribution in the melted snow samples were measured using a nebulizer and a single-particle soot photometer (SP2). In the experiment where melting temperature was varied, the BC mass concentration in the liquid decreased at a melting temperature of 70 °C. This decrease was 8.0 % for the Shirouma sample and 46.4 % for the Hakusan sample and depended on BC particle size, with a significant decrease found at BC diameters less than 350 nm. A similar decrease in BC mass concentration was found when the Hakusan snow sample that had been melted at 5 °C was heated to 70 °C. The experiment in which melting time was varied indicated that BC mass concentration in the liquid did not change for the Shirouma sample but decreased significantly with a longer melting time for the Hakusan sample (38.6 %). These results indicate that melting of snow samples at high temperatures or over long time periods can significantly affect the measurement of BC mass and its size distribution, especially for aged snow samples.
The contribution of trees and grasses to productivity of an Australian tropical savanna
Authors: Moore Caitlin E. , Beringer Jason , Evans Bradley , Hutley Lindsay B. , McHugh Ian , Tapper Nigel J.
Published: April 2016

Abstract. Savanna ecosystems cover 20 % of the global land surface and account for 25 % of global terrestrial carbon uptake. They support one fifth of the world's human population and are one of the most important ecosystems on our planet. Savanna productivity is a product of the interplay between trees and grass that co-dominate savanna landscapes and are maintained through interactions with climate and disturbance (fire, land use change, herbivory). In this study, we evaluate the temporally dynamic partitioning of overstory and understory carbon dioxide fluxes in Australian tropical savanna using overstory and understory eddy covariance measurements. Over a 2-year period (September 2012 to October 2014) the overall net ecosystem productivity (NEP) of the savanna was 506.2 (±22 SE) g C m−2 yr−1. The total gross primary productivity (GPP) was 2267.1 (±80 SE) g C m−2 yr−1, of which the understory contributed 32 %. The understory contribution was strongly seasonal, with most GPP occurring in the wet season (40 % of total ecosystem in the wet season and 18 % in the dry). This study is the first to elucidate the temporal dynamics of savanna understory and overstory carbon flux components explicitly using observational information. Understanding grass productivity is crucial for evaluating fuel loads, as is tree productivity for quantifying the tree carbon sink. This information will contribute to a significant refinement of the representation of savannas in models, as well as improved understanding of relative tree-grass productivity and competition for resources.
A Late Pleistocene sea level stack
Authors: Spratt Rachel M. , Lisiecki Lorraine E.
Published: April 2016

Abstract. Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal component analysis (PCA) on seven records from 0 to 430 ka and five records from 0 to 798 ka. The first principal component, which we use as the stack, describes  ∼  80 % of the variance in the data and is similar using either five or seven records. After scaling the stack based on Holocene and Last Glacial Maximum (LGM) sea level estimates, the stack agrees to within 5 m with isostatically adjusted coral sea level estimates for Marine Isotope Stages 5e and 11 (125 and 400 ka, respectively). Bootstrapping and random sampling yield mean uncertainty estimates of 9–12 m (1σ) for the scaled stack. Sea level change accounts for about 45 % of the total orbital-band variance in benthic δ18O, compared to a 65 % contribution during the LGM-to-Holocene transition. Additionally, the second and third principal components of our analyses reflect differences between proxy records associated with spatial variations in the δ18O of seawater.
Effect of polluted water on soil and plant contamination by heavy metals in El-Mahla El-Kobra, Egypt
Authors: Mahmoud Esawy Kasem , Ghoneim Adel Mohamed
Published: April 2016

Abstract. The discharge of untreated waste water in Zefta drain and drain no. 5 is becoming a problem for many farmers in the El-Mahla El-Kobra area, Egypt. The discharged water contains high levels of contaminants considered hazardous to the ecosystem. Some plants, soil, water, and sediment samples were collected from the El-Mahla El-Kobra area to evaluate the contamination by heavy metals. The results showed that the heavy metals, pH, sodium adsorption ratio (SAR), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) in the water of Zefta drain and drain no. 5 exceeded permissible limits for irrigation. In rice and maize shoots grown in soils irrigated by contaminated water from Zefta drain and drain no. 5, the bioaccumulation factors for Cd, Pb, Zn, Cu, and Mn were higher than 1.0. The heavy metals content of irrigated soils from Zefta drain and drain no. 5 exceeded the upper limit of background heavy metals. In this study, the mean contaminant factor values of the drain no. 5 sediments revealed that Zn, Mn, Cu, Cd, Pb, and Ni > 6, indicating very high contamination. The bioaccumulation coefficient values of Cynodon dactylon, Phragmites australis, and Typha domingensis aquatic plants growing in Zefta drain are high. These species can be considered as hyperaccumulators for the decontamination of contaminated water.
Vegetation cover change detection and assessment in arid environment using multi-temporal remote sensing images and ecosystem management approach
Authors: Aly Anwar Abdelrahman , Al-Omran Abdulrasoul Mosa , Sallam Abdulazeam Shahwan , Al-Wabel Mohammad Ibrahim , Al-Shayaa Mohammad Shayaa
Published: April 2016

Abstract. Vegetation cover (VC) change detection is essential for a better understanding of the interactions and interrelationships between humans and their ecosystem. Remote sensing (RS) technology is one of the most beneficial tools to study spatial and temporal changes of VC. A case study has been conducted in the agro-ecosystem (AE) of Al-Kharj, in the center of Saudi Arabia. Characteristics and dynamics of total VC changes during a period of 26 years (1987–2013) were investigated. A multi-temporal set of images was processed using Landsat images from Landsat4 TM 1987, Landsat7 ETM+2000, and Landsat8 to investigate the drivers responsible for the total VC pattern and changes, which are linked to both natural and social processes. The analyses of the three satellite images concluded that the surface area of the total VC increased by 107.4 % between 1987 and 2000 and decreased by 27.5 % between years 2000 and 2013. The field study, review of secondary data, and community problem diagnosis using the participatory rural appraisal (PRA) method suggested that the drivers for this change are the deterioration and salinization of both soil and water resources. Ground truth data indicated that the deteriorated soils in the eastern part of the Al-Kharj AE are frequently subjected to sand dune encroachment, while the southwestern part is frequently subjected to soil and groundwater salinization. The groundwater in the western part of the ecosystem is highly saline, with a salinity  ≥ 6 dS m−1. The ecosystem management approach applied in this study can be used to alike AE worldwide.
Mechanism of Seasonal Arctic Sea Ice Evolution and Arctic Amplification
Authors: Kim Kwang-Yul , Hamlington Benjamin D. , Na Hanna , Kim Jinju
Published: April 2016

Abstract. Sea ice melting is proposed as a primary reason for the Artic amplification, although physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice melting in the Arctic Ocean and the Arctic amplification. While sea ice melting is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains to be thin in winter only in the Barents-Kara Seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice melting warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be ice free. A 1 % reduction in sea ice concentration in winter leads to ~ 0.76 W m−2 increase in upward heat flux, ~ 0.07 K increase in 850 hPa air temperature, ~ 0.97 W m−2 increase in downward longwave radiation, and ~ 0.26 K increase in surface air temperature. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort Seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara Seas and Laptev, East Siberian, Chukchi, and Beaufort Seas.
El bono social y las cooperativas energéticas verdes: situación y perspectivas
Authors: Jaio Gabiola Egoitz , Paredes Gázquez Juan Diego , Sánchez Rodríguez José Antonio
Published: April 2016

Las tarifas sociales son, junto con la transferencia de rentas y las medidas de eficiencia energética, uno de los instrumentos para paliar la pobreza energética. A la tarifa social española, creada en el año 2009 se le denomina “bono social”.Para acceder al bono social, aparte de cumplir los requisitos socioeconómicos estipulados por ley, hay que tener contratada la electricidad con alguna comercializadora de referencia, las cuales tienen la obligación de ofrecer el bono social.Las cooperativas energéticas verdes, un fenómeno reciente, al no ser comercializadoras de referencia, no están obligadas a ofrecer el bono social. Esto no quiere decir que entre los socios de estas cooperativas no haya personas vulnerables o en riesgo de pobreza energética.Este trabajo centra su análisis en dos objetivos. El primero es trazar el perfil socioeconómico del socio de las cooperativas verdes. El segundo es observar si estos socios tienen derecho al bono social actual, así como a otras tarifas sociales alternativas con requisitos diferentes a los del bono social.Para ello, se realiza una encuesta a los socios de la mayor cooperativa energética verde de España. Los resultados evidencian que sí existe riesgo de pobreza energética entre los socios de las cooperativas energéticas verdes, si bien su incidencia depende de cómo se defina al consumidor vulnerable.
A QUESTÃO DA DIFERENÇA E DAS RELAÇÕES EM RICHARD HARTSHORNE - DOI 10.5216/bgg.v36i1.40366
Authors: Castilho Denis
Published: April 2016

As proposições teóricas do geógrafo estadunidense Richard Hartshorne são um convite à reflexão. Baseadas principalmente nas concepções de Alfred Hettner, constituem-se como importante contribuição ao estudo da natureza da Geografia, tal como indica o próprio título de seu trabalho publicado em 1939, The Nature of Geography: A Critical Survey of Current Thought in the Light of the Past. A preocupação com a essência dessa disciplina levou o autor a apresentar, neste e em um texto de 1959 (Perspective on the Nature of Geography), uma sistematização de ideias e proposições de importantes clássicos do pensamento geográfico que o antecederam, especialmente do século XIX. Dentre os principais conceitos apresentados nessas publicações,destacam-se o de diferenciação de área, bastante difundido (e confundido) entre os geógrafos, e os de relação e conexão, muito vinculados pelo autor à questão sempre reiterada em seus trabalhos: aquela referente aocaráter variável da superfície terrestre. Com base nessas premissas, este trabalho apresenta uma análise desses conceitos, discute seus limites teóricos e evidencia questões relacionadas às suas possibilidadesanalíticas.Palavras-chave: Richard Hartshorne, diferenciação, relação, conexão.
A “Partilha do Gorila” entre ciência e literatura de alhures e saberes locais
Authors: Correa Silvio Marcus de Souza
Published: April 2016

O artigo mostra como certos saberes locais sobre o gorila foram apropriados pela ciência e pela literatura desde meados do século XIX. O estudo sobre a circulação dos saberes permite perceber os papeis e a importancia dos africanos na base do conhecimento produzido no campo cientifico e literario sobre os gorilas.