33 results
Self-Organized Inorganic-Organic Hybrids Induced by Silylating Agents with Phyllosilicate-Like Structure and the Influence of the Adsorption of Cations
- Maria G. Da Fonseca, José S. Barone, Claudio Airoldi
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- Journal:
- Clays and Clay Minerals / Volume 48 / Issue 6 / December 2000
- Published online by Cambridge University Press:
- 28 February 2024, pp. 638-647
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Two analogous inorganic-organic hybrids with a phyllosilicate-like structure SILMg1 and SILMg2, containing 3-aminopropyl- and N-propylethylenediaminetrimethoxysilane were synthesized through a sol-gel process. These hybrids adsorbed divalent cations of cobalt, nickel, copper, and zinc from aqueous solution to give the effectiveness of adsorption capacities in the sequence Cu2+ > Zn2+ > Ni2+ > Co2+. SILMg1 has a higher capacity of adsorption than SILMg2. Elemental analysis, X-ray diffractometry, thermal analysis, infrared and nuclear magnetic resonance spectroscopies, and energy dispersive system microscopy characterized all hybrids. The proposed adsorption mechanism involves dissolution of the precursor matrix, formation of a phyllosilicate around the adsorbed ion, and a complexation of the cation by the amino-pendant groups in the interlayer. These new phyllosilicates are more crystalline than the original hybrids. The adsorption of Co2+ increases the interlayer distance to maximum values of 1.81 and 2.24 Å for SILMg1 and SILMg2, respectively. Thermal analysis data showed a decrease of thermal stability with cation adsorption. Si-O-Si groups were detected by infrared spectroscopy in all hybrids and a band at 1384 cm-1 was assigned to the nitrate counter anion, which indicates the participation of this ion in the sphere of coordination of the interlayer complexes. The photomicrographs obtained by scanning electron microscopy showed the organized distribution of the sheet structure for these synthesized phyllosilicates.
Social media influence on Eating Disorders since COVID-19 pandemic: a pilot study
- F. Micanti, G. Spennato, R. Claudio, E. Amoroso, M. D’Ambrosio, V. M. Saia, A. Barone, M. Tadic, D. Galletta, M. Vannini
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- Journal:
- European Psychiatry / Volume 66 / Issue S1 / March 2023
- Published online by Cambridge University Press:
- 19 July 2023, p. S218
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Introduction
Several studies show a negative impact of mass media contents on adolescents’ mental health, especially on perceived body uneasiness. COVID-19 lockdown determined an increased use of social networks (SN). Psychiatrists highlighted an increase in Eating Disorders’ (ED) diagnoses.
ObjectivesThe aim of this study is to assess the pattern of SN use in patients with ED using a self-administered questionnaire.
Methods30 patients with clinical diagnosis of ED (Anorexia nervosa, Bulimia nervosa or Binge eating disorder) admitted to the ED unit, underwent clinical assessment, and filed a questionnaire on SN use. The questionnaire assesses time spent on SN, weight-control apps use, exposure to fitness- or food-related contents and to ED-promoting contents, distractibility, weight changes and feeling of body uneasiness.
ResultsMean age was 20.63 (SD 4.71), mean BMI 20.24 (SD 5.27); 93.3% (28) of patients were females. Eating behaviours were divided into restrictive type (66.7%, 20) or binge/bulimic (33.3%, 10). 16.7% (5) of patients reported self-injury behaviours. In 46.7% (14) of cases, the onset of the ED occurred during COVID-19 pandemic; the remaining 53.3% (16) experienced a relapse of a previous ED during this period. 66.7% (20) of subjects reported an increased use of social media and fitness apps. 90% (27) experienced weight changes during the pandemic, with 76.7% (23) seeking nutritional or psychological interventions. 53.3% (16) perceived an increase in body- or food-related contents on their SN feeds, with 50% declaring of knowing the meaning of the terms pro-ana and pro-mia.
Table 1 displays reported answers to the questionnaire. Table 2 shows mean age of patients according to self-injury behaviours and to the onset time of ED.
Table 1. Questionnaire subscales (n) Rarely occurred % (n) Often occurred % (n) Increase of time spent on SNs (30) 33.3% (10) 66.7% (20) Distractibility (30) 70% (21) 30% (9) Self-injury contents (30) 96.7% (1) 3.3% (29) Body uneasiness (30) 26.7% (8) 73.3% (22) Pro-ana/pro-mia contents influence (15) 53.3% (8) 46.7% (7) Body- and food-related contents influence (30) 20% (6) 80% (24) Table 2. Eating disorders features (n) Mean age (SD) Self-injury – Yes (5) 18.20 (1.92) p<0.05 Self-injury – No (25) 21.12 (4.97) Onset during Covid-19 pandemic (14) 18.29 (1.82) p<0.01 Worsening during Covid-19 pandemic (16) 22.69 (5.51) ConclusionsED onset during the COVID-19 pandemic and self-injury behaviours appear as pivotal characteristics of younger patients, displaying a greater severity of the disorder in our clinical experience. With a more consistent number of patients, it would be possible to correlate SN use and body- and food-related contents to the onset and the severity of ED, focusing on pandemic periods.
Disclosure of InterestNone Declared
Maternal protein restriction during the lactation period disrupts the ontogenetic development of behavioral traits in male Wistar rat offspring
- Juliana de Oliveira-Silva, Patrícia C. Lisboa, Bruna Lotufo-Denucci, Mabel Fraga, Egberto G. de Moura, Fernanda C. Nunes, Anderson Ribeiro-Carvalho, Cláudio C. Filgueiras, Yael Abreu-Villaça, Alex C. Manhães
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- Journal:
- Journal of Developmental Origins of Health and Disease / Volume 14 / Issue 3 / June 2023
- Published online by Cambridge University Press:
- 26 April 2023, pp. 341-352
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Neonatal undernutrition in rats results in short- and long-term behavioral and hormonal alterations in the offspring. It is not clear, however, whether these effects are present since the original insult or if they develop at some specific age later in life. Here, we assessed the ontogenetic profile of behavioral parameters associated with anxiety, exploration and memory/learning of Wistar rat offspring that were subjected to protein malnutrition during lactation. Dams and respective litters were separated into two groups: (1) protein-restricted (PR), which received a hypoproteic chow (8% protein) from birth to weaning [postnatal day (PN) 21]; (2) control (C), which received normoproteic chow. Offspring’s behaviors, corticosterone, catecholamines, T3 and T4 levels were assessed at PN21 (weaning), PN45 (adolescence), PN90 (young adulthood) or PN180 (adulthood). PR offspring showed an age-independent reduction in the levels of anxiety-like behaviors in the Elevated Plus Maze and better memory performance in the Radial Arm Water Maze. PR offspring showed peak exploratory activity in the Open Field earlier in life, at PN45, than C, which showed theirs at PN90. Corticosterone was reduced in PR offspring, particularly at young adulthood, while catecholamines were increased at weaning and adulthood. The current study shows that considerable age-dependent variations in the expression of the observed behaviors and hormonal levels exist from weaning to adulthood in rats, and that protein restriction during lactation has complex variable-dependent effects on the ontogenesis of the assessed parameters.
Sphingolipids and acylcarnitines are altered in placentas from women with gestational diabetes mellitus
- Gabriela D. A. Pinto, Antonio Murgia, Carla Lai, Carolina S. Ferreira, Vanessa A. Goes, Deborah de A. B. Guimarães, Layla G. Ranquine, Desirée L. Reis, Claudio J. Struchiner, Julian L. Griffin, Graham J. Burton, Alexandre G. Torres, Tatiana El-Bacha
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- Journal:
- British Journal of Nutrition / Volume 130 / Issue 6 / 28 September 2023
- Published online by Cambridge University Press:
- 21 December 2022, pp. 921-932
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- 28 September 2023
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Gestational diabetes mellitus (GDM) is the most common medical complication of pregnancy and a severe threat to pregnant people and offspring health. The molecular origins of GDM, and in particular the placental responses, are not fully known. The present study aimed to perform a comprehensive characterisation of the lipid species in placentas from pregnancies complicated with GDM using high-resolution MS lipidomics, with a particular focus on sphingolipids and acylcarnitines in a semi-targeted approach. The results indicated that despite no major disruption in lipid metabolism, placentas from GDM pregnancies showed significant alterations in sphingolipids, mostly lower abundance of total ceramides. Additionally, very long-chain ceramides and sphingomyelins with twenty-four carbons were lower, and glucosylceramides with sixteen carbons were higher in placentas from GDM pregnancies. Semi-targeted lipidomics revealed the strong impact of GDM on the placental acylcarnitine profile, particularly lower contents of medium and long-chain fatty-acyl carnitine species. The lower contents of sphingolipids may affect the secretory function of the placenta, and lower contents of long-chain fatty acylcarnitines is suggestive of mitochondrial dysfunction. These alterations in placental lipid metabolism may have consequences for fetal growth and development.
21 - Replication and Reproducibility in Primate Cognition Research
- Edited by Bennett L. Schwartz, Florida International University, Michael J. Beran, Georgia State University
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- Primate Cognitive Studies
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- 28 July 2022
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- 11 August 2022, pp 532-550
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Summary
Replication is an important tool used to test and develop scientific theories. Areas of biomedical and psychological research have experienced a replication crisis, in which many published findings failed to replicate. Following this, many other scientific disciplines have been interested in the robustness of their own findings. This chapter examines replication in primate cognitive studies. First, it discusses the frequency and success of replication studies in primate cognition and explores the challenges researchers face when designing and interpreting replication studies across the wide range of research designs used across the field. Next, it discusses the type of research that can probe the robustness of published findings, especially when replication studies are difficult to perform. The chapter concludes with a discussion of different roles that replication can have in primate cognition research.
First de novo transcriptome analysis of the Antarctic springtail Cryptopygus terranovus (Collembola: Isotomidae) following mid-term heat exposure
- Claudio Cucini, Chiara Leo, Francesco Nardi, Samuele Greco, Chiara Manfrin, Piero G. Giulianini, Antonio Carapelli
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- Journal:
- Antarctic Science / Volume 33 / Issue 5 / October 2021
- Published online by Cambridge University Press:
- 08 June 2021, pp. 459-468
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Global human activities, such as greenhouse emissions and pollution, are promoting global warming, environmental changes and biodiversity reduction. Pristine environments such as those of Antarctica are not immune to these phenomena, as is noticeable from the increasing pace of the temperature shift registered within the continent in recent decades. In this study, we describe the first de novo transcriptome analysis of the endemic Antarctic springtail (= collembolan) Cryptopygus terranovus and we evaluate its global gene expression response following a mid-term exposure of 20 days to 18°C. Expression data are compared with wild specimens sampled from their native environment to outline the molecular mechanisms triggered by the thermal exposure. Although individual plasticity in transcript modulation is assessed, several pathways appear to be differentially modulated in springtails subjected to the heat treatment vs wild specimens. Through enrichment analysis, we show that protein catabolism, fatty acid metabolism and a sexual response characterized by spermatid development are induced, while carbohydrate consumption, lipid catabolism and tissue development are downregulated in treated samples compared to controls.
Chapter 12 - Brown Bear (Ursus arctos; Eurasia)
- from Part II - Species Accounts
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- By Jon E. Swenson, Hüseyin Ambarlı, Jon M. Arnemo, Leonid Baskin, Paolo Ciucci, Pjotr I. Danilov, Miguel Delibes, Marcus Elfström, Alina L. Evans, Claudio Groff, Anne G. Hertel, Djuro Huber, Klemen Jerina, Alexandros A. Karamanlidis, Jonas Kindberg, Ilpo Kojola, Miha Krofel, Josip Kusak, Tsutomu Mano, Mario Melletti, Yorgos Mertzanis, Andrés Ordiz, Santiago Palazón, Jamshid Parchizadeh, Vincenzo Penteriani, Pierre-Yves Quenette, Agnieszka Sergiel, Nuria Selva, Ivan Seryodkin, Michaela Skuban, Sam M.J.G. Steyaert, Ole-Gunnar Støen, Konstantin F. Tirronen, Andreas Zedrosser
- Edited by Vincenzo Penteriani, Mario Melletti
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- Bears of the World
- Published online:
- 16 November 2020
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- 26 November 2020, pp 139-161
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Summary
This chapter comprises the following sections: names, taxonomy, subspecies and distribution, descriptive notes, habitat, movements and home range, activity patterns, feeding ecology, reproduction and growth, behavior, parasites and diseases, status in the wild, and status in captivity.
Early life risk and resiliency factors and their influences on developmental outcomes and disease pathways: a rapid evidence review of systematic reviews and meta-analyses
- Ayah Abdul-Hussein, Ayesha Kareem, Shrankhala Tewari, Julie Bergeron, Laurent Briollais, John R. G. Challis, Sandra T. Davidge, Claudio Delrieux, Isabel Fortier, Daniel Goldowitz, Pablo Nepomnaschy, Ashley Wazana, Kristin L. Connor
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- Journal of Developmental Origins of Health and Disease / Volume 12 / Issue 3 / June 2021
- Published online by Cambridge University Press:
- 04 August 2020, pp. 357-372
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The Developmental Origins of Health and Disease (DOHaD) framework aims to understand how environmental exposures in early life shape lifecycle health. Our understanding and the ability to prevent poor health outcomes and enrich for resiliency remain limited, in part, because exposure–outcome relationships are complex and poorly defined. We, therefore, aimed to determine the major DOHaD risk and resilience factors. A systematic approach with a 3-level screening process was used to conduct our Rapid Evidence Review following the established guidelines. Scientific databases using DOHaD-related keywords were searched to capture articles between January 1, 2009 and April 19, 2019. A final total of 56 systematic reviews/meta-analyses were obtained. Studies were categorized into domains based on primary exposures and outcomes investigated. Primary summary statistics and extracted data from the studies are presented in Graphical Overview for Evidence Reviews diagrams. There was substantial heterogeneity within and between studies. While global trends showed an increase in DOHaD publications over the last decade, the majority of data reported were from high-income countries. Articles were categorized under six exposure domains: Early Life Nutrition, Maternal/Paternal Health, Maternal/Paternal Psychological Exposure, Toxicants/Environment, Social Determinants, and Others. Studies examining social determinants of health and paternal influences were underrepresented. Only 23% of the articles explored resiliency factors. We synthesized major evidence on relationships between early life exposures and developmental and health outcomes, identifying risk and resiliency factors that influence later life health. Our findings provide insight into important trends and gaps in knowledge within many exposures and outcome domains.
A pilot study of clonazepam versus psychodynamic group therapy plus clonazepam in the treatment of generalized social anxiety disorder
- Daniela Z. Knijnik, Carlos Blanco, Giovanni Abrahão Salum, Carolina U. Moraes, Clarissa Mombach, Ellen Almeida, Marília Pereira, Atahualpa Strapasson, Gisele G. Manfro, Cláudio L. Eizirik
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- European Psychiatry / Volume 23 / Issue 8 / December 2008
- Published online by Cambridge University Press:
- 16 April 2020, pp. 567-574
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Background
Both psychodynamic group therapy (PGT) and clonazepam are used as treatment strategies in reducing symptoms of generalized social anxiety disorder (GSAD). However, many individuals remain symptomatic after treatment with PGT or clonazepam.
MethodFifty-eight adult outpatients with a diagnosis of GSAD according to DSM-IV were randomized to 12 weeks PGT plus clonazepam or clonazepam. The Clinical Global Impression-Improvement (CGI-I) Scale was the primary efficacy measure. Secondary efficacy measures included the Liebowitz Social Anxiety Scale (LSAS) total score, the World Health Organization Instrument to Assess Quality of Life—Brief (WHOQOL-Bref) Scale and the Beck Depression Inventory (BDI).
ResultsCGI-I data from 57 patients (intent-to-treat population) showed that patients who received PGT plus clonazepam presented significantly greater improvement than those who received clonazepam (P = 0.033). There were no significant differences between the two groups in the secondary efficacy measures.
ConclusionsOur study suggests that the combination of PGT with clonazepam may be a promising strategy for the treatment of GSAD, regarding gains in the global functioning. However the present study failed to detect more specific changes in social anxiety symptomatology between the two groups.
Nutraceutical support in heart failure: a position paper of the International Lipid Expert Panel (ILEP)
- Arrigo F. G. Cicero, Alessandro Colletti, Stephan von Haehling, Dragos Vinereanu, Agata Bielecka-Dabrowa, Amirhossein Sahebkar, Peter P. Toth, Željko Reiner, Nathan D. Wong, Dimitri P. Mikhailidis, Claudio Ferri, Maciej Banach
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- Journal:
- Nutrition Research Reviews / Volume 33 / Issue 1 / June 2020
- Published online by Cambridge University Press:
- 16 March 2020, pp. 155-179
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Heart failure (HF) is a complex clinical syndrome that represents a major cause of morbidity and mortality in Western countries. Several nutraceuticals have shown interesting clinical results in HF prevention as well as in the treatment of the early stages of the disease, alone or in combination with pharmacological therapy. The aim of the present expert opinion position paper is to summarise the available clinical evidence on the role of phytochemicals in HF prevention and/or treatment that might be considered in those patients not treated optimally as well as in those with low therapy adherence. The level of evidence and the strength of recommendation of particular HF treatment options were weighed up and graded according to predefined scales. A systematic search strategy was developed to identify trials in PubMed (January 1970 to June 2019). The terms ‘nutraceuticals’, ‘dietary supplements’, ‘herbal drug’ and ‘heart failure’ or ‘left verntricular dysfunction’ were used in the literature search. The experts discussed and agreed on the recommendation levels. Available clinical trials reported that the intake of some nutraceuticals (hawthorn, coenzyme Q10, l-carnitine, d-ribose, carnosine, vitamin D, probiotics, n-3 PUFA and beet nitrates) might be associated with improvements in self-perceived quality of life and/or functional parameters such as left ventricular ejection fraction, stroke volume and cardiac output in HF patients, with minimal or no side effects. Those benefits tended to be greater in earlier HF stages. Available clinical evidence supports the usefulness of supplementation with some nutraceuticals to improve HF management in addition to evidence-based pharmacological therapy.
People and jaguars: new insights into the role of social factors in an old conflict
- Flavia Caruso, Pablo G. Perovic, Andrés Tálamo, Carolina B. Trigo, María S. Andrade-Díaz, Gustavo A. Marás, Diego Saravia, Claudio Sillero-Zubiri, Mariana Altrichter
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Throughout its range in Latin America, the jaguar Panthera onca is threatened by habitat loss and fragmentation, and by conflict as a result of coexistence with people. This Near Threatened species is a top predator, and is often illegally hunted. Understanding people's attitudes and perceptions and the factors that could influence them is crucial for the conservation of this species. In this study we assess how knowledge, attitudes and perceptions among people in northern Argentina regarding jaguars vary depending on their level of education, age and occupation. We interviewed 810 people living in and around 10 protected areas in northern Argentina. Positive perceptions and attitudes towards the jaguar were associated with economic benefits that people may receive from the species’ presence, such as income from tourism. Unexpectedly, higher levels of formal education were not associated with more positive attitudes and perceptions. Negative attitudes and perceptions towards the species were determined by fear; people see jaguars as a threat to their lives. This study shows that the socio-economic factors that affect the level of tolerance towards jaguars are not related only to economic losses. Our findings provide information for the design, implementation and evaluation of jaguar conservation projects in Argentina.
Spanish Version of the Satisfaction with Life Scale: Validation and Factorial Invariance Analysis in Chile
- Mehdi Bagherzadeh, Nicolas Loewe, Roy G. Mouawad, Joan Manuel Batista-Foguet, Luis Araya-Castillo, Claudio Thieme
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- The Spanish Journal of Psychology / Volume 21 / 2018
- Published online by Cambridge University Press:
- 01 March 2018, E2
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The aim of this study is to: (1) examine the psychometric properties of the Spanish version of the Satisfaction with Life scale (SWLS) on a representative sample of the Chilean population (N = 1,500); (2) test the factorial invariance of the SWLS across gender and employment status (henceforth status); and (3) provide normative data of the SWLS for Chile. Results suggest that the Spanish version of the SWLS is a valid and reliable instrument for measuring global life satisfaction in Chile and for comparison across gender and status. Confirmatory factor analysis shows support, across all groups, for a modified single-factor structure of the SWLS that allows error terms of items 1 and 2 to correlate (GFI > .98; RMSEA < .08). Cronbach’s alpha coefficient ranges between .68 and .84 for different groups, with an average value of .80 for the total sample. The SWLS scores converge with an alternative single-item measure of life satisfaction (r = .63, p < .001) and with measures of conceptually related constructs. The factorial structure of the scale is invariant with respect to gender and status (CFI > .99; RMSEA < .06). Metric invariance holds for gender (ΔCFI = 0; RMSEA = .051) and status (Δχ2 = 23.93, nonsignificant; ∆CFI = 0; RMSEA = .045). Scalar invariance holds for gender and some status combinations; partial scalar invariance holds for the rest. Mean levels of life satisfaction can be compared across gender and status, albeit cautiously for status combinations for which scalar invariance does not hold.
Arginine and aerobic training prevent endothelial and metabolic alterations in rats at high risk for the development of the metabolic syndrome
- Renata F. Medeiros, Thaiane G. Gaique, Thais Bento-Bernardes, Raquel Kindlovits, Tamiris M. B. Gomes, Nadia Alice V. Motta, Fernanda Carla Brito, Caroline Fernandes-Santos, Karen J. Oliveira, Antonio Claudio L. Nóbrega
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- Journal:
- British Journal of Nutrition / Volume 118 / Issue 1 / 14 July 2017
- Published online by Cambridge University Press:
- 11 August 2017, pp. 1-10
- Print publication:
- 14 July 2017
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Endothelial function is a key mechanism in the development of CVD. Arginine and exercise are important non-pharmacological strategies for mitigating the impact of metabolic changes in the metabolic syndrome, but the effect of their combined administration is unknown. Thus, the aim of this study was to investigate the isolated and combined effects of aerobic training and arginine supplementation on metabolic variables and vascular reactivity in rats at high risk for developing the metabolic syndrome. Wistar rats were divided into two groups: control and fructose (F – water with 10 % fructose). After 2 weeks, the F group was divided into four groups: F, fructose+arginine (FA, 880 mg/kg per d of l-arginine), fructose+training (FT) and fructose+arginine+training (FTA); treatments lasted for 8 weeks, and no difference was observed in body mass gain. Arginine did not improve the body protein content, and both the FA and FT groups show a reversal of the increase in adipose tissue. Insulin increase was prevented by training and arginine, without additive effect, and the increase in serum TAG was prevented only by training. The F group showed impaired endothelium-dependent vasodilation and hyperreactivity to phenylephrine, but arginine and training were capable of preventing these effects, even separately. Higher nitric oxide level was observed in the FA and FT groups, and no potentiating effect was detected. Thus, only training was able to prevent the increase in TAG and improve the protein mass, and training and arginine exert similar effects on fat content, insulin and endothelial function, but these effects are not additive.
Use of Gene Flow to Control Diclofop-Methyl Resistance in Italian Ryegrass (Lolium multiflorum)
- Claudio M. Ghersa, Maria A. Martinez-Ghersa, Timothy G. Brewer, Mary Lynn Roush
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- Weed Technology / Volume 8 / Issue 1 / March 1994
- Published online by Cambridge University Press:
- 12 June 2017, pp. 139-147
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Flower production and pollen dispersal patterns of diclofop-methyl-susceptible and -resistant Italian ryegrass were examined to determine whether evolution of herbicide resistance could be controlled by cross-fertilization between biotypes. The susceptible and resistant ryegrass biotypes differed in timing and abundance of both ovule production and pollen release such that pollen from the susceptible plants had a much greater chance of fertilizing the resistant plant population than vice versa. Susceptible ryegrass, growing with or without wheat competition, produced more than 60% of its seeds before any pollen from resistant plants was released. In contrast, throughout the course of resistant plant seed generation, pollen from susceptible plants composed at least 30% of the total pollen load. These phenological differences, in conjunction with herbicide treatment results for third-generation ryegrass seedlings, suggest that gene flow can be used to reduce development of diclofop-methyl resistance in ryegrass populations within wheat cropping systems. In a wheat field infested with resistant ryegrass, cessation of herbicide application and sowing of a susceptible ryegrass biotype can be expected to reduce the evolution of diclofop-methyl resistance by at least 6% per year.
Environmental history since 11,000 14c yr b.p. of the northeastern Pampas, Argentina, from alluvial sequences of the Luján River
- Aldo R. Prieto, Adriana M. Blasi, Claudio G. De Francesco, Celina Fernández
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- Quaternary Research / Volume 62 / Issue 2 / September 2004
- Published online by Cambridge University Press:
- 20 January 2017, pp. 146-161
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Sedimentological, malacological, and pollen analyses from 14C-dated alluvial sections from the Luján River provide a detailed record of environmental changes during the Holocene in the northeastern Pampas of Argentina. From 11,200 to 9000 14C yr B.P., both sedimentary and biological components suggest that the depositional environment was eutrophic, alkaline, and freshwater to brackish shallow water bodies without significant water circulation. During this time, bioclastic sedimentation was dominant and the shallow water bodies reached maximum development as the climate became more humid, suggesting an increase in precipitation. Short-term fluctuations in climate during the last stage of this interval may have been sufficient to initiate changes in the water bodies, as reduction of the volume alternated with periods of flooding. The beginning of the evolution of shallow swamps in the wide floodplain or huge wetlands was contemporaneous with a sea level lower than the present one. From 9000 and 7000 14C yr B.P., mesotrophic, alkaline, brackish, probably anoxic swamps existed. Between 7000 and 3000 14C yr B.P., anoxic calcareous swamps were formed, with subaerial exposure and development of the Puesto Berrondo Soil (3500–2900 14C yr B.P.). A trend to a reduction of water bodies is recorded from 9000 to ca. 3000 14C yr B.P., with a significant reduction after ca. 7000 14C yr B.P. A shift to subhumid–dry climate after 7000 14C yr B.P. appears to be the main cause. During this time, an additional external forcing toward higher groundwater levels was caused by Holocene marine transgression causing changes in the water bodies levels. The climate became drier during the late Holocene (ca. 3000 yr B.P.), when clastic sedimentation increased, under subhumid–dry conditions. Flood events increased in frequency during this time. From ca. A.D. 1790 to present, the pollen record reflects widespread disturbance of the vegetation during the European settlement.
Effect of Niobium on the Microstructure of High Chromium White Cast Iron
- Cláudio. G. Oliveira, Ivete.P. Pinheiro
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- MRS Online Proceedings Library Archive / Volume 1816 / 2016
- Published online by Cambridge University Press:
- 22 July 2016, imrc2015abso45
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- 2016
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Equipment wear is caused by the disintegration of material due to the contact between the machines components and the ore, resulting in stress to the surface of the material. Wear causes loss of efficiency, vibration, misalignment and, in severe cases, cracks that may lead to fracture and damage to the equipment. In mining, wear is caused by operational problems in which generate high costs. Some researchers studied white cast iron alloys with high chromium and the addition of niobium for wear plates manufacturing and therefore, plates to protect structural parts of the equipment have been developed. This study presents the characterization of the microstructure of two alloys of white cast iron with high chromium containing 3.8 wt.% C and 27.1 wt.% Cr and the addition of 0.9 wt.% Nb (alloy 1) and 1.6 wt.% Nb (alloy 2), respectively. Samples of the two alloys were subjected to metallographic tests, microhardness and abrasion type rubber wheel tests, according to the ASTM: G65-91 standard. Complexes carbides have been identified in both alloys. The results of microhardness and wear resistance tests were correlated and identified the effect of niobium addition. The findings suggest that the addition of niobium in these alloys contributes to the formation of NbC and increase of Cr in the matrix; consequently increase in the hardenability of the material. The wear resistance of alloy 2 was 47.95% higher than alloy 1 in abrasion type rubber wheel tests. It demonstrates that the increase of niobium in the alloy has contributed to improve wear resistance due to the substantial change in the microstructure and distribution of NbC carbides.
Active camera stabilization to enhance the vision of agile legged robots
- Stéphane Bazeille, Jesus Ortiz, Francesco Rovida, Marco Camurri, Anis Meguenani, Darwin G. Caldwell, Claudio Semini
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Legged robots have the potential to navigate in more challenging terrains than wheeled robots. Unfortunately, their control is more demanding, because they have to deal with the common tasks of mapping and path planning as well as more specific issues of legged locomotion, like balancing and foothold planning. In this paper, we present the integration and the development of a stabilized vision system on the fully torque-controlled hydraulically actuated quadruped robot (HyQ). The active head added onto the robot is composed of a fast pan and tilt unit (PTU) and a high-resolution wide angle stereo camera. The PTU enables camera gaze shifting to a specific area in the environment (both to extend and refine the map) or to track an object while navigating. Moreover, as the quadruped locomotion induces strong regular vibrations, impacts or slippages on rough terrain, we took advantage of the PTU to mechanically compensate for the robot's motions. In this paper, we demonstrate the influence of legged locomotion on the quality of the visual data stream by providing a detailed study of HyQ's motions, which are compared against a rough terrain wheeled robot of the same size. Our proposed Inertial Measurement Unit (IMU)-based controller allows us to decouple the camera from the robot motions. We show through experiments that, by stabilizing the image feedback, we can improve the onboard vision-based processes of tracking and mapping. In particular, during the outdoor tests on the quadruped robot, the use of our camera stabilization system improved the accuracy on the 3D maps by 25%, with a decrease of 50% of mapping failures.
Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- Book:
- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment
- Cláudio M. D. de Souza, Cristine E. A. Carneiro, João Paulo T. Baú, Antonio C. S. da Costa, Flávio F. Ivashita, Andrea Paesano, Jr, Eduardo di Mauro, Henrique de Santana, Nils G. Holm, Anna Neubeck, Cássia T. B. V. Zaia, Dimas A. M. Zaia
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- Journal:
- International Journal of Astrobiology / Volume 12 / Issue 2 / April 2013
- Published online by Cambridge University Press:
- 07 February 2013, pp. 135-143
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In the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pHPZC decreased and the pHIEP increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not +II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM–EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch Types (FTT) reactions in hydrothermal vent systems. X-ray diffractograms of the original forsterite-91 also showed peaks arising from zeolites and clinochlore. After the samples were treated with artificial seawater, X-ray diffractograms showed the dissolution of zeolite. Experiments should be performed in the natural environment to verify the potential for zeolites to act as a catalyst in hydrothermal vents.
Contributors
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- By Luis G. Acevedo, Schahram Akbarian, Ioanna Andreou, Krishnarao Appasani, Raghu K. Appasani, Julia Arand, David M. Ashley, Alexander R. Ball, Yehudit Bergman, Marina Bibikova, Angela Bithell, Francesca Bonafè, Eric E. Bouhassira, Victoria L. Boyd, Noel J. Buckley, Lars Olov Bygren, Claudio M. Caldarera, Gemma Carvill, James W. F. Catto, Sarah Derks, Ewa Dudziec, Jeffrey D. Falk, Jian-Bing Fan, Joseph M. Fernandez, David E. Fisher, Emanuela Fiumana, Tamara B. Franklin, Fei Gao, Arkadiusz Gertych, Emanuele Giordano, David Goldman, Markus Grammel, Carlo Guarnieri, Kevin L. Gunderson, Victoria (Fatemeh) G. Haghighi, Xu Han, Yong-Mahn Han, Howard C. Hang, Aditi Hazra, Laura B.K. Herzing, Norbert Hochstein, Robin Holliday, Dorothee Honsel, Mary A. Jelinek, Guanyu Ji, Yan Jiang, Atsushi Kaneda, Richard A. Katz, Hyemin Kim, Richard Kroon, Tapas K. Kundu, Benoit Labonté, Daeyoup Lee, Konstantin Lepikhov, Andrea Linnemann-Florl, Dirk Loeffert, Dylan Maixner, Isabelle M. Mansuy, Andreas Missel, D. V. Mohankrishna, Joana Carvalho Moreira de Mello, Paolo G. Morselli, Rituparna Mukhopadhyay, Claudio Muscari, Takashi Nagano, Frank Narz, Shuji Ogino, Carlo M. Oranges, Shari Orlanski, Alice Pasini, Ralf Peist, Lygia V. Pereira, Andrey Poleshko, Claire Rougeulle, Thea Rütjes, Ana Sanz, Benjamin G. Schroeder, Gerald Schock, Kornel Schuebel, B. Ruthrotha Selvi, Hogyu Seo, Natalia Shalginskikh, Andrew Sharp, Jun S. Song, Lennart Suckau, Azim Surani, Jian Tajbakhsh, Gustavo Turecki, Céline Vallot, Manon van Engeland, Jörn Walter, Nicholas C. Wong, Mark Wossidlo, Honglong Wu, Yurong Xin, Zhixiang Yan, Yu-Ying Yang, Mingzhi Ye, Kyoko Yokomori, Sephorah Zaman, Weihua Zeng, Gerald Zon
- Edited by Krishnarao Appasani
- Foreword by Azim Surani, University of Cambridge
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- Book:
- Epigenomics
- Published online:
- 05 August 2012
- Print publication:
- 02 August 2012, pp x-xxiv
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