WorldWideScience

Sample records for understand natural rates

  1. Understanding Interest Rate Volatility

    DEFF Research Database (Denmark)

    Volker, Desi

    with and without stochastic volatility to capture the main stylized features of U.S. interest rates. The third essay, \\Variance Risk Premia in the Interest Rate Swap Market", investigates the time-series and cross-sectional properties of the compensation demanded for holding interest rate variance risk. The essays...... are self-contained and can be read independently. There is however a common thread in the themes covered as all essays focus on the understanding of interest rate volatility, its time-variation and main determinants....

  2. Intuitive Understanding of Base Rates

    DEFF Research Database (Denmark)

    Austin, Laurel

    Purpose: This study examines whether physicians and other adults intuitively understand that the probability a positive test result is a true positive (positive predictive value, PPV) depends on the base rate of disease in the population tested. In particular, this research seeks to examine...

  3. Research in Natural Language Understanding

    Science.gov (United States)

    1978-08-31

    of the lexical material to explain how many actions there were, how many actors , etc., and the nature of the map from actor onto action, etc. For...direction and make a measurement there, or may scan from the current focus in a specified " direccion " (or by some other specification of a trajectory

  4. Theoretical approaches to natural language understanding

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    This book discusses the following: Computational Linguistics, Artificial Intelligence, Linguistics, Philosophy, and Cognitive Science and the current state of natural language understanding. Three topics form the focus for discussion; these topics include aspects of grammars, aspects of semantics/pragmatics, and knowledge representation.

  5. What is 'Natural' in Natural Selection? To understand Darwin's ...

    Indian Academy of Sciences (India)

    IAS Admin

    level, and it could be at the level of populations. If we underline the distinctive nature of changes at different levels of biological organisation, we can understand how they are related in the long history of life. .... selection lies in the usefulness of variations: in their being “useful to man” or “useful in some way to each being” ...

  6. Formation rate of natural gas hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Mork, Marit

    2002-07-01

    The rate of methane hydrate and natural gas hydrate formation was measured in a 9.5 litre stirred tank reactor of standard design. The experiments were performed to better understand the performance and scale-up of a reactor for continuous production of natural gas hydrates. The hydrate formation rate was measured at steady-state conditions at pressures between 70 and 90 bar and temperatures between 7 and 15 deg C. Between 44 and 56 % of the gas continuously supplied to the reactor was converted to hydrate. The experimental results show that the rate of hydrate formation is strongly influenced by gas injection rate and pressure. The effect of stirring rate is less significant and subcooling has no observable effect on the formation rate. Hydrate crystal concentration and gas composition do not influence the hydrate formation rate. Observations of produced hydrate crystals indicate that the crystals are elongated, about 5 micron in diameter and 10 micron long. Analysis of the results shows that the rate of hydrate formation is dominated by gas-liquid mass transfer. A mass transfer model, the bubble-to-crystal model, was developed for the hydrate formation rate in a continuous stirred tank reactor, given in terms of concentration driving force and an overall mass transfer coefficient. The driving force is the difference between the gas concentration at the gas-liquid interface and at the hydrate crystal surface. These concentrations correspond to the solubility of gas in water at experimental temperature and pressure and the solubility of gas at hydrate equilibrium temperature and experimental pressure, respectively. The overall mass transfer coefficient is expressed in terms of superficial gas velocity and impeller power consumption, parameters commonly used in study of stirred tank reactors. Experiments and modeling show that the stirred tank reactor has a considerable potential for increased production capacity. However, at higher hydrate production rates the

  7. Natural and anthropogenic rates of soil erosion

    Science.gov (United States)

    Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natur...

  8. Evaluation And Analysis of Natural Gas Rates

    International Nuclear Information System (INIS)

    Taheri, Ali Akbar

    1999-01-01

    Natural gas is considered as a preferred fuel and its utility is growing every day in the country (Iran). The usage of natural gas has increased from 3.5 to 44 billion cubic meters from 1980 to 1997, respectively. Currently, 4 million residences and most of the industrial sector are being provided with the pipelined natural gas. Because of the tremendous increase in consumption, it is necessary to give the needed considerations to natural gas rate structure. The objective of the paper is to 1.Evaluate the fundamentals and principal methods used for rate structures. 2. Identification of effective components. 3. Analyze the current rates including connection fees and other customer charges

  9. PHILOSOPHICAL UNDERSTANDING OF THE NATURE OF VIOLENCE

    Directory of Open Access Journals (Sweden)

    N. M. Boychenko

    2017-12-01

    Full Text Available Purpose. In order to consistently distinguish between violence, which is always primarily a destructive force, and the civilized use of force that involves constructive, creative goals, one should explore the main possible philosophical approaches to understand the nature of violence and try to give it a systematic outline. Methodology. This study uses a systematic approach to identify the internal relationship between different forms of violence and, accordingly, the counteraction against violence. Also, the author uses an axiology to identify the values that are the basis for distinguishing violence from its prototypes, as well as for the distinction between violence and coercion, as well as different types of coercion. Originality. This article presents significant clarifications on the classification of types of violence, in particular, it is clearly established that certain types of violence can not have ethical relevance, since they belong to the sphere of biology (expansion, aggression or social anthropology (cultural, institutional coercion. Actually violence or violence in the narrow sense implies the existence of will, consciousness and destructive purpose. Accordingly, counteraction against violence should include the formation of a certain non-violent type of will, non-violent culture and creative, constructive goals. This requires both personal effort and institutional support and the availability of appropriate moral traditions. Ethical theory is intended to clarify and systematize these efforts. In this sense, ethics is the core of practical philosophy. To the extent that the influence of ethics on changes in human culture and sociality in the counterfactual regime is increasing, one should also speak of the anthropological significance of ethics. Conclusions. From the socio-philosophical point of view, it is necessary to specify exactly which social institutions and in which constellation generate violence. The ethical aspect of

  10. Natural Weathering Rates of Silicate Minerals

    Science.gov (United States)

    White, A. F.

    2003-12-01

    Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to "the efficacy of water containing carbonic acid in promoting the decomposition of igneous rocks." Antecedent to the recent interest in the role of vegetation on chemical weathering, Belt (1874) observed that the most intense weathering of rocks in tropical Nicaragua was confined to forested regions. He attributed this effect to "the percolation through rocks of rain water charged with a little acid from decomposing vegetation." Chamberlin (1899) proposed that the enhanced rates of chemical weathering associated with major mountain building episodes in Earth's history resulted in a drawdown of atmospheric CO2 that led to periods of global cooling. Many of the major characteristics of chemical weathering had been described when Merrill (1906) published the groundbreaking volume Rocks, Rock Weathering, and Soils.The major advances since that time, particularly during the last several decades, have centered on understanding the fundamental chemical, hydrologic, and biologic processes that control weathering and in establishing quantitative weathering rates. This research has been driven by the importance of chemical weathering to a number environmentally and economically important issues. Undoubtedly, the most significant aspect of chemical weathering is the breakdown of rocks to form soils, a process that makes life possible on the surface of the Earth. The availability of many soil macronutrients such as magnesium, calcium, potassium, and PO4 is directly related to the rate at which primary minerals weather. Often such nutrient balances are upset by anthropogenic

  11. The natural gas industry and interest rates

    International Nuclear Information System (INIS)

    Yoon, Y.J.

    1995-01-01

    In discussing the impact of Federal Energy Regulatory Commission (FERC) Order 636, the latest rule on the restructuring and deregulation of the US natural gas industry, the effect of interest rates on the success of the FERC policy is often overlooked. The thesis of this paper is that interest rates play an important role in integrating seasonal gas markets and in stimulating investment in storage infrastructure. We propose a model to analyse the equilibrium condition for an efficient gas market. Also analysed are the implications of pipeline rate design of FERC 636 for gas despatch decisions. (author)

  12. What is 'Natural' in Natural Selection? To understand Darwin's ...

    Indian Academy of Sciences (India)

    IAS Admin

    to circumvent a major misconception, if they fail to appreciate that natural selection is consequent on the variation's usefulness for the variant, not on the static or changing environmental conditions. For example, Darwin writes, “[A]ny variation, however slight and from whatever cause proceeding, if it be in any degree.

  13. [Human nature--understanding psychology in Nietzsche].

    Science.gov (United States)

    Dieckhöfer, K

    1980-01-01

    It was tried to show some decisive and essential points of the psychological analyses contained in the complex work of the philosopher Nietzsche. The extent of his knowledge of man and his changeability constitutes here the field of an understanding, "unmasking" psychology with a sociological-historical touch. The thorough, slow ("lento") study of the original sources on the part of the master of a "connaisseurship of the word" seems to be indispensable for any reader trying to occupy himself with Nietzsche in a work of his own and the questions arising therefrom.

  14. Is the natural rate of growth exogenous?

    OpenAIRE

    Miguel Leon-Ledesma; Anthony P. Thirlwall

    2000-01-01

    In mainstream growth theory, including endogenous growth theory, the naturalrate of growth as defined by Harrod, is still treated as exogenous. In practice, however, both the growth of the labour force and the growth of labour productivity are endogenous to demand. This has theoretical implications for the adjustment process between the actual, warranted and natural growth rates. It also has serious implications for the way in which the growth process is viewed: whether from the supply side o...

  15. Natural and anthropogenic rates of soil erosion

    Directory of Open Access Journals (Sweden)

    Mark A. Nearing

    2017-06-01

    Full Text Available Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natural, non-cropped conditions have been documented to be less than 2 Mg ha−1 yr−1. On-site rates of erosion of lands under cultivation over large cropland areas, such as in the United States, have been documented to be on the order of 6 Mg ha−1 yr−1 or more. In northeastern China, lands that were brought into production during the last century are thought to have average rates of erosion over this large area of as much as 15 Mg ha−1 yr−1 or more. Broadly applied soil conservation practices, and in particular conservation tillage and no-till cropping, have been found to be effective in reducing rates of erosion, as was seen in the United States when the average rates of erosion on cropped lands decreased from on the order of 9 Mg ha−1 yr−1 to 6 or 7 Mg ha−1 yr−1 between 1982 and 2002, coincident with the widespread adoption of new conservation tillage and residue management practices. Taking cropped lands out of production and restoring them to perennial plant cover, as was done in areas of the United States under the Conservation Reserve Program, is thought to reduce average erosion rates to approximately 1 Mg ha−1 yr−1 or less on those lands.

  16. Epistemological Predictors of Prospective Biology Teachers' Nature of Science Understandings

    Science.gov (United States)

    Köseoglu, Pinar; Köksal, Mustafa Serdar

    2015-01-01

    The purpose of this study was to investigate epistemological predictors of nature of science understandings of 281 prospective biology teachers surveyed using the Epistemological Beliefs Scale Regarding Science and the Nature of Science Scale. The findings on multiple linear regression showed that understandings about definition of science and…

  17. A guide to understanding social science research for natural scientists.

    Science.gov (United States)

    Moon, Katie; Blackman, Deborah

    2014-10-01

    Natural scientists are increasingly interested in social research because they recognize that conservation problems are commonly social problems. Interpreting social research, however, requires at least a basic understanding of the philosophical principles and theoretical assumptions of the discipline, which are embedded in the design of social research. Natural scientists who engage in social science but are unfamiliar with these principles and assumptions can misinterpret their results. We developed a guide to assist natural scientists in understanding the philosophical basis of social science to support the meaningful interpretation of social research outcomes. The 3 fundamental elements of research are ontology, what exists in the human world that researchers can acquire knowledge about; epistemology, how knowledge is created; and philosophical perspective, the philosophical orientation of the researcher that guides her or his action. Many elements of the guide also apply to the natural sciences. Natural scientists can use the guide to assist them in interpreting social science research to determine how the ontological position of the researcher can influence the nature of the research; how the epistemological position can be used to support the legitimacy of different types of knowledge; and how philosophical perspective can shape the researcher's choice of methods and affect interpretation, communication, and application of results. The use of this guide can also support and promote the effective integration of the natural and social sciences to generate more insightful and relevant conservation research outcomes. © 2014 Society for Conservation Biology.

  18. Diagnosing Students' Understanding of the Nature of Models

    Science.gov (United States)

    Gogolin, Sarah; Krüger, Dirk

    2017-10-01

    Students' understanding of models in science has been subject to a number of investigations. The instruments the researchers used are suitable for educational research but, due to their complexity, cannot be employed directly by teachers. This article presents forced choice (FC) tasks, which, assembled as a diagnostic instrument, are supposed to measure students' understanding of the nature of models efficiently, while being sensitive enough to detect differences between individuals. In order to evaluate if the diagnostic instrument is suitable for its intended use, we propose an approach that complies with the demand to integrate students' responses to the tasks into the validation process. Evidence for validity was gathered based on relations to other variables and on students' response processes. Students' understanding of the nature of models was assessed using three methods: FC tasks, open-ended tasks and interviews ( N = 448). Furthermore, concurrent think-aloud protocols ( N = 30) were performed. The results suggest that the method and the age of the students have an effect on their understanding of the nature of models. A good understanding of the FC tasks as well as a convergence in the findings across the three methods was documented for grades eleven and twelve. This indicates that teachers can use the diagnostic instrument for an efficient and, at the same time, valid diagnosis for this group. Finally, the findings of this article may provide a possible explanation for alternative findings from previous studies as a result of specific methods that were used.

  19. Biological and social understanding of human nature: biopolitical dimension

    Directory of Open Access Journals (Sweden)

    S. K. Kostiuchkov

    2014-07-01

    Full Text Available This paper examines the position of the biopolitical nature of man as a biosocial being given supplies of both the two spheres of life – natural, biological and social. The necessity of understanding of human nature, which by definition are bio-social importance of the approach to the definition of man as an integral, binary-konnotovanoyi of the «social individual – a species» which is characterized by symmetrical opposition – upposition social and biological. It was found that the main task of modern political science, and in particular bio-political studies presented appeals to rethink the political picture of the world in order to predict the development of a new order or a new chaos. Understanding the formation of a new global civilization worldview is today one of the most important problems, which is connected with the main problem of the modern world – the task of preserving life on the planet. It is concluded that the contradictions of human nature – between the biological and the social, physical and spiritual, universal and the particular, natural and artificial, rational and emotional – in today’s conditions are extremely sharp. The said situation requires more in-depth scientific analysis of human nature, the study of the structural level as human biosocial system.

  20. Public understandings of nature: a case study of local knowledge about "natural" forest conditions

    Science.gov (United States)

    R. Bruce Hull; David P. Robertson; Angelina Kendra

    2001-01-01

    This study is intended to serve as an explicit and specific example of the social construction of nature. It is motivated by the need to develop a more sophisticated language for a critical public dialogue about society's relationship with nature. We conducted a case study of environmental discourse in one local population in hopes of better understanding how a...

  1. Revising the human mutation rate: implications for understanding human evolution.

    Science.gov (United States)

    Scally, Aylwyn; Durbin, Richard

    2012-10-01

    It is now possible to make direct measurements of the mutation rate in modern humans using next-generation sequencing. These measurements reveal a value that is approximately half of that previously derived from fossil calibration, and this has implications for our understanding of demographic events in human evolution and other aspects of population genetics. Here, we discuss the implications of a lower-than-expected mutation rate in relation to the timescale of human evolution.

  2. Understanding Marine Biocorrosion: Experiments with Artificial and Natural Seawater

    Science.gov (United States)

    2015-11-04

    9781782421252.3.329 Copyright © 2014 European Federation of Corrosion . Published by Elsevier Ltd. All rights reserved. Understanding marine biocorrosion...many years there has been a debate over the preferred laboratory medium for studying marine corrosion , i.e., natural or artifi cial seawater (Dexter...study of microbiologically infl uenced marine corrosion (MIMC) and the consideration of nutrients for microorganisms. Recent MIMC investigations have

  3. Nurse ethical awareness: Understanding the nature of everyday practice.

    Science.gov (United States)

    Milliken, Aimee; Grace, Pamela

    2017-08-01

    Much attention has been paid to the role of the nurse in recognizing and addressing ethical dilemmas. There has been less emphasis, however, on the issue of whether or not nurses understand the ethical nature of everyday practice. Awareness of the inherently ethical nature of practice is a component of nurse ethical sensitivity, which has been identified as a component of ethical decision-making. Ethical sensitivity is generally accepted as a necessary precursor to moral agency, in that recognition of the ethical content of practice is necessary before consistent action on behalf of patient interests can take place. This awareness is also compulsory in ensuring patient good by recognizing the unique interests and wishes of individuals, in line with an ethic of care. Scholarly and research literature are used to argue that bolstering ethical awareness and ensuring that nurses understand the ethical nature of the role are an obligation of the profession. Based on this line of reasoning, recommendations for education and practice, along with directions for future research, are suggested.

  4. Understanding and managing compliance in the nature conservation context.

    Science.gov (United States)

    Arias, Adrian

    2015-04-15

    Nature conservation relies largely on peoples' rule adherence. However, noncompliance in the conservation context is common: it is one of the largest illegal activities in the world, degrading societies, economies and the environment. Understanding and managing compliance is key for ensuring effective conservation, nevertheless crucial concepts and tools are scattered in a wide array of literature. Here I review and integrate these concepts and tools in an effort to guide compliance management in the conservation context. First, I address the understanding of compliance by breaking it down into five key questions: who?, what?, when?, where? and why?. A special focus is given to 'why?' because the answer to this question explains the reasons for compliance and noncompliance, providing critical information for management interventions. Second, I review compliance management strategies, from voluntary compliance to coerced compliance. Finally, I suggest a system, initially proposed for tax compliance, to balance these multiple compliance management strategies. This paper differs from others by providing a broad yet practical scope on theory and tools for understanding and managing compliance in the nature conservation context. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Medical problem and document model for natural language understanding.

    Science.gov (United States)

    Meystre, Stephanie; Haug, Peter J

    2003-01-01

    We are developing tools to help maintain a complete, accurate and timely problem list within a general purpose Electronic Medical Record system. As a part of this project, we have designed a system to automatically retrieve medical problems from free-text documents. Here we describe an information model based on XML (eXtensible Markup Language) and compliant with the CDA (Clinical Document Architecture). This model is used to ease the exchange of clinical data between the Natural Language Understanding application that retrieves potential problems from narrative document, and the problem list management application.

  6. Do Predation Rates on Artificial Nests Accurately Reflect Predation Rates on Natural Bird Nests?

    Science.gov (United States)

    David I. King; Richard M. DeGraaf; Curtice R. Griffin; Thomas J. Maier

    1999-01-01

    Artificial nests are widely used in avian field studies. However, it is unclear how well predation rates on artificial nests reflect predation rates on natural nests. Therefore, we compared survival rates of artificial nests (unused natural nests baited with House Sparrow eggs) with survival rates of active bird nests in the same habitat at the same sites. Survival...

  7. Supply Constraints on Employment and Output: NAIRU Versus Natural Rate

    OpenAIRE

    James Tobin

    1997-01-01

    NAIRU and NATURAL RATE are not synonymous. NAIRU is a macro outcome of an economy with many labor markets in diverse states of excess demand and excess supply. NAIRU represents an overall balance between the inflation-increasing pressures from excess-demand markets and the inflation-decreasing pressures from excess-supply markets. The natural rate, as described by Friedman, is a feature of Walrasian market-clearing general equilibrium. While the NAIRU fits into a Keynesian model, the natural ...

  8. Narrativity and enaction: the social nature of literary narrative understanding.

    Science.gov (United States)

    Popova, Yanna B

    2014-01-01

    This paper proposes an understanding of literary narrative as a form of social cognition and situates the study of such narratives in relation to the new comprehensive approach to human cognition, enaction. The particular form of enactive cognition that narrative understanding is proposed to depend on is that of participatory sense-making, as developed in the work of Di Paolo and De Jaegher. Currently there is no consensus as to what makes a good literary narrative, how it is understood, and why it plays such an irreplaceable role in human experience. The proposal thus identifies a gap in the existing research on narrative by describing narrative as a form of intersubjective process of sense-making between two agents, a teller and a reader. It argues that making sense of narrative literature is an interactional process of co-constructing a story-world with a narrator. Such an understanding of narrative makes a decisive break with both text-centered approaches that have dominated both structuralist and early cognitivist study of narrative, as well as pragmatic communicative ones that view narrative as a form of linguistic implicature. The interactive experience that narrative affords and necessitates at the same time, I argue, serves to highlight the active yet cooperative and communal nature of human sociality, expressed in the many forms than human beings interact in, including literary ones.

  9. Tracking Students' Understanding of the Particle Nature of Matter

    Science.gov (United States)

    Merritt, Joi Deshawn

    One reason students find it difficult to learn the particle model of matter is that traditional curriculum materials present concepts to students without helping them to develop these ideas. The How can I smell things from a distance? sixth grade chemistry unit takes the approach of building students' ideas through their construction and revision of models. Progress variables have been proposed as a means to address the need for curriculum and assessments that can help teachers' improve their practice as well as to inform both students and teachers about students' performance. Progress variables depict students' increasingly sophisticated conceptions of a specific construct during instruction. This study provides evidence that curriculum and assessment based on modern learning theories, can lead to the development of progress variables that are able to track middle school students' understanding of the particle nature of matter over time. This study used a progress variable to track student understanding of the particle nature of matter during the sixth grade chemistry unit. I describe the assessment system used to develop the progress variable for tracking students' development of particle model of matter during the sixth grade chemistry unit. A calibration study determined that the chemistry unit's assessments were reliable and valid measures of the particle model of matter progress variable. Further analysis revealed that the progress variable had to be modified such that the levels were more distinct. The modified progress variable was empirically validated so that it could be used to track students' understanding during instruction. Results indicate that a validated progress variable, linked to coherent curriculum and assessments can provide valid interpretations of students' knowledge of particular domain during instruction and that this progress variable is valid for students from varying populations and backgrounds. In addition, well-aligned curriculum and

  10. Systems biology approaches to understand natural products biosynthesis

    Directory of Open Access Journals (Sweden)

    Cuauhtemoc eLicona-Cassani

    2015-12-01

    Full Text Available Actinomycetes populate soils and aquatic sediments which impose biotic and abiotic challenges for their survival. As a result, actinomycetes metabolism and genomes have evolved to produce an overwhelming diversity of specialized molecules. Polyketides, non-ribosomal peptides, post-translationally modified peptides, lactams and terpenes are well known bioactive natural products with enormous industrial potential. Accessing such biological diversity has proven difficult due to the complex regulation of cellular metabolism in actinomycetes and to the sparse knowledge of their physiology. The past decade, however, has seen the development of omics technologies that have significantly contributed to our better understanding of their biology. Key observations have contributed towards a shift in the exploitation of actinomycetes biology, such as using their full genomic potential, activating entire pathways through key metabolic elicitors and pathway engineering to improve biosynthesis. Here, we review recent efforts devoted to achieving enhanced discovery, activation and manipulation of natural product biosynthetic pathways in model actinomycetes using genome-scale biological datasets.

  11. Time trends in the natural dizygotic twinning rate.

    Science.gov (United States)

    Derom, Catherine; Gielen, Marij; Peeters, Hilde; Frijns, Jean-Pierre; Zeegers, Maurice P A

    2011-08-01

    The natural dizygotic (DZ) twinning rate has been proposed as a reliable and useful measure of human fecundity, if adjusted for maternal age at twin birth. The aim of this study was to analyze age-adjusted trends in natural DZ twinning rates over the past 40 years using data from the 'East Flanders Prospective Twin Survey (EFPTS)'. This study involved 4835 naturally conceived twin pregnancies between 1969 and 2009 from the population-based Belgian 'EFPTS'. Age-adjusted trends in the incidence of natural DZ twin pregnancies were calculated using a generalized linear model with Poisson distribution. Both the natural DZ twinning rates and maternal age at twin birth increased in a linear fashion from 1969 to 2009. When age-adjusted, we found that the trend in the natural DZ twinning rate was stable during the whole time period. According to our population-based data and after age-adjustment, a stable natural DZ twinning rate could be observed over the last four decades. Under the assumption that the spontaneous DZ twinning rate is a sensor of fecundity, this indicates a stable 'high' fecundity for this population.

  12. Scientific literacy: Role of natural history studies in constructing understanding of the nature of science

    Science.gov (United States)

    Lutz, Martha Victoria Rosett

    2002-01-01

    Scientific literacy is a central goal of science education. One purpose of this investigation was to reevaluate the definition of 'scientific literacy.' Another purpose was to develop and implement new curriculum involving natural history experiments with insects, with the goal of allowing students opportunities to construct an understanding of the nature of science, a crucial aspect of scientific literacy. This investigation was a qualitative case study. Methods of data collection included direct observations, analysis of sketches and written products created by students and class-room teachers, and analysis of audio tapes. Major findings include: (1) Scientific literacy is generally defined by lists of factual information which students are expected to master. When asked to evaluate their knowledge of selected items on a list published in a science education reform curriculum guide, 15 practicing scientists reported lack of familiarity or comprehension with many items, with the exception of items within their areas of specialization. (2) Genuine natural history experiments using insects can be incorporated into the existing school schedule and need not require any increase in the budget for science materials. (3) Students as young as first through third grade can learn the manual techniques and conceptual skills necessary for designing and conducting original natural history experiments, including manipulating the insects, making accurate sketches, developing test able hypotheses, recording data, and drawing conclusions from their data. Students were generally enthusiastic both about working with live insects and also conducting genuine science experiments. (4) Girls appear both positive and engaged with natural history activities and may be more likely than boys to follow through on designing, conducting, and reporting on independent experiments. The results imply that a valid definition of scientific literacy should be based on the ability to acquire scientific

  13. Understanding recall rates in screening mammography: A conceptual framework review of the literature

    International Nuclear Information System (INIS)

    Mohd Norsuddin, N.; Reed, W.; Mello-Thoms, C.; Lewis, S.J.

    2015-01-01

    Recall rates are one of the performance measures used to evaluate the effectiveness of mammography screening programs. There is conflicting evidence regarding the link between recall rates and cancer detection rates and a variety of differing recall rates exist between countries and readers. This variability in recall rates may have important clinical and economic implications such as unnecessary follow-up procedures, additional costs to the health care system and psychological effects for the women themselves associated with false-positive mammograms results. In order to reduce the impact of false positive recall rates in screening mammography, it is essential for all multidisciplinary health care providers, especially those in medical imaging, to fully understand the factors that may contribute and affect recall rates. The multifactorial nature of recall rates is explored in this paper through the construction of a conceptual map based on a review of the current literature. - Highlights: • Recall rates vary across countries and readers and for initial and subsequent screens. • Falsely recalling women has important clinical, cost and psycho-social implications. • Imaging technology, readers' expertise and patient presentation affect recall rates. • Higher recall rates do not translate into improved sensitivity at higher thresholds. • Multidisciplinary approaches to reduce recall rates may improve women experiences.

  14. Understanding European education landscape on natural disasters - a textbook research

    Science.gov (United States)

    Komac, B.; Zorn, M.; Ciglič, R.; Steinführer, A.

    2012-04-01

    The importance of natural-disaster education for social preparedness is presented. Increasing damage caused by natural disasters around the globe draws attention to the fact that even developed societies must adapt to natural processes. Natural-disaster education is a component part of any education strategy for a sustainably oriented society. The purpose of this article is to present the role of formal education in natural disasters in Europe. To ensure a uniform overview, the study used secondary-school geography textbooks from the collection at the Georg Eckert Institute for International Textbook Research in Braunschweig, Germany. Altogether, nearly 190 textbooks from 35 European countries were examined. The greatest focus on natural disasters can be found in textbooks published in western Europe (3.8% of pages describing natural disasters), and the smallest in those published in eastern Europe (0.7%). A share of textbook pages exceeding three percent describing natural disasters can also be found in northern Europe (3.6%) and southeast Europe, including Turkey (3.4%). The shares in central and southern Europe exceed two percent (i.e., 2.8% and 2.3%, respectively). The types and specific examples of natural disasters most commonly covered in textbooks as well as the type of natural disasters presented in textbooks according to the number of casualties and the damage caused were analyzed. The results show that the majority of European (secondary-school) education systems are poorly developed in terms of natural-disaster education. If education is perceived as part of natural-disaster management and governance, greater attention should clearly be dedicated to this activity. In addition to formal education, informal education also raises a series of questions connected with the importance of this type of education. Special attention was drawn to the importance of knowledge that locals have about their region because this aspect of education is important in both

  15. Natural stream flow-rates measurements by tracer techniques

    International Nuclear Information System (INIS)

    Cuellar Mansilla, J.

    1982-01-01

    This paper presents the study of the precision obtained measuring the natural stream flow rates by tracer techniques, especially when the system presents a great slope and a bed constituted by large and extended particle size. The experiences were realized in laboratory pilot channels with flow-rates between 15 and 130 [1/s]; and in natural streams with flow-rates from 1 to 25 m 3 /s. Tracer used were In-133m and Br-82 for laboratory and field measurements respectively. In both cases the tracer was injected as a pulse and its dilution measured collecting samples in the measured section, at constant flow-rates, of 5[1] in laboratory experiences and 60[1] of water in field experiences. Precisions obtained at a 95% confidence level were about 2% for laboratory and 3% for field. (I.V.)

  16. Macroeconomic Stabilization When the Natural Real Interest Rate Is Falling

    Science.gov (United States)

    Buttet, Sebastien; Roy, Udayan

    2015-01-01

    The authors modify the Dynamic Aggregate Demand-Dynamic Aggregate Supply model in Mankiw's widely used intermediate macroeconomics textbook to discuss monetary policy when the natural real interest rate is falling over time. Their results highlight a new role for the central bank's inflation target as a tool of macroeconomic stabilization. They…

  17. Coolant rate distribution in horizontal steam generator under natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A. [St. Petersburg State Technical Univ. (Russian Federation)

    1997-12-31

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered. 5 refs.

  18. An APOS analysis of natural science students' understanding of ...

    African Journals Online (AJOL)

    schema) theoretical framework to investigate university students' understanding of derivatives and their applica-tions. Research was done at the Westville Campus of the University of KwaZulu-Natal in South Africa. The relevant rules for finding ...

  19. Understanding the Nature of X-ray Weak Quasars

    Science.gov (United States)

    Brandt, William

    We propose a program of archival X-ray and related studies designed to advance understanding of the remarkable active galactic nucleus (AGN) population of X-ray weak quasars. These exceptional objects reveal phenomena that are more generally applicable but are difficult to investigate when more subtly expressed in the overall quasar population. X-ray weak quasars furthermore challenge a central tenet of X-ray astronomy that luminous X-ray emission is a universal property of efficiently accreting supermassive black holes; this idea underlies the utility of X-ray surveys for identifying AGNs throughout the Universe. Our previous findings indicate that understanding of Xray weak quasars is now primed for rapid further advances. Our studies of X-ray weak quasars will employ data from the vast archives of forefront X-ray missions, particularly XMM-Newton and Chandra, and they will also benefit greatly from the use of NuSTAR, ROSAT, Suzaku, Swift, GALEX, and WISE data. They are largely enabled by the enormous quasar samples delivered by modern widefield sky surveys. In particular, we will identify X-ray weak quasars using the serendipitous X-ray coverage of the 380,000 relatively bright quasars spectroscopically identified by the Sloan Digital Sky Survey (SDSS) from z 0.1-5.5; these are wellmatched to the depths of typical archival X-ray observations. The number of SDSS spectroscopic quasars has more than tripled in recent years, and the sample-size improvements at redshifts of z = 2-4, important for our investigations, are even more dramatic. We will construct an unprecedented new sample of X-ray weak quasars, about 20 times larger than those used currently, to enable systematic studies of the X-ray weakness phenomenon. This work should reveal the cause of X-ray weakness for quasars with weak emission lines, allowing testing of a model that relies upon small-scale shielding of ionizing photons by a thick inner accretion disk around a black hole accreting at a high

  20. Natural Disasters and Cholera Outbreaks: Current Understanding and Future Outlook.

    Science.gov (United States)

    Jutla, Antarpreet; Khan, Rakibul; Colwell, Rita

    2017-03-01

    Diarrheal diseases remain a serious global public health threat, especially for those populations lacking access to safe water and sanitation infrastructure. Although association of several diarrheal diseases, e.g., cholera, shigellosis, etc., with climatic processes has been documented, the global human population remains at heightened risk of outbreak of diseases after natural disasters, such as earthquakes, floods, or droughts. In this review, cholera was selected as a signature diarrheal disease and the role of natural disasters in triggering and transmitting cholera was analyzed. Key observations include identification of an inherent feedback loop that includes societal structure, prevailing climatic processes, and spatio-temporal seasonal variability of natural disasters. Data obtained from satellite-based remote sensing are concluded to have application, although limited, in predicting risks of a cholera outbreak(s). We argue that with the advent of new high spectral and spatial resolution data, earth observation systems should be seamlessly integrated in a decision support mechanism to be mobilize resources when a region suffers a natural disaster. A framework is proposed that can be used to assess the impact of natural disasters with response to outbreak of cholera, providing assessment of short- and long-term influence of climatic processes on disease outbreaks.

  1. The frequency and nature of medical error in primary care: understanding the diversity across studies.

    Science.gov (United States)

    Sandars, John; Esmail, Aneez

    2003-06-01

    The identification and reduction of medical error has become a major priority for all health care providers, including primary care. Understanding the frequency and nature of medical error in primary care is a first step in developing a policy to reduce harm and improve patient safety. There has been scant research into this area. This review had two objectives; first, to identify the frequency and nature of error in primary care, and, secondly, to consider the possible causes for the diversity in the stated rates and nature of error in primary care. Literature searches of English language studies identified in the National Patient Safety Foundation bibliography database, in Medline and in Embase were carried out. Studies that were relevant to the purpose of the study were included. Additional information was obtained from a specialist medico-legal database. Studies identified that medical error occurs between five and 80 times per 100000 consultations, mainly related to the processes involved in diagnosis and treatment. Prescribing and prescription errors have been identified to occur in up to 11% of all prescriptions, mainly related to errors in dose. There are a wide variety of definitions and methods used to identify the frequency and nature of medical error. Incident reporting, systematic identification and medico-legal databases reveal differing aspects, and there are additional perspectives obtained from GPs, primary health care workers and patients. An understanding of the true frequency and nature of medical error is complicated by the different definitions and methods used in the studies. Further research is warranted to understand the complex nature and causes of such errors that occur in primary care so that appropriate policy decisions to improve patient safety can be made.

  2. Dilemmas in Examining Understanding of Nature of Science in Vietnam

    Science.gov (United States)

    Thao-Do, Thi Phuong; Yuenyong, Chokchai

    2017-01-01

    Scholars proved nature of science (NOS) has made certain contributions to science teaching and learning. Nonetheless, what, how and how much NOS should be integrated in the science curriculum of each country cannot be a benchmark, due to the influence of culture and society. Before employing NOS in a new context, it should be carefully studied. In…

  3. The Influence of Argumentation on Understanding Nature of Science

    Science.gov (United States)

    Boran, Gül Hanim; Bag, Hüseyin

    2016-01-01

    The aim in conducting this study is to explore the effects of argumentation on pre-service science teachers' views of the nature of science. This study used a qualitative case study and conducted with 20 pre-service science teachers. Data sources include an open-ended questionnaire and audio-taped interviews. According to pretest and posttest…

  4. Understanding relations between pastoralism and its changing natural environment

    NARCIS (Netherlands)

    Tamou, Charles

    2017-01-01

    The competition for land has become an issue of major concern and cause of conflict, especially between pastoralists and crop farmers, but also between pastoralists and nature conservation institutions. The Biosphere Reserve of W in Benin Republic (WBR) and its surrounding lands are located in

  5. Homo Ethicus : Understanding the Human Nature that Underlies ...

    African Journals Online (AJOL)

    Abstract. The themes of human rights and human rights education in South Africa's multi-cultural society are central to the work of Cornelia Roux. This article discusses the human reality and ethics underlying those themes, using an approach based on a view of human nature. It has six sections, starting with an introduction ...

  6. Dilemmas in Examining Understanding of Nature of Science in Vietnam

    Science.gov (United States)

    Hatherley-Greene, Peter

    2017-01-01

    The two authors, Thi Phuong Thao-Do and Chokchai Yuenyong, explored the Nature of Science as it is understood in Vietnam, a fast-developing "ancient" and modern country which continues to be shaped by uniquely Asian social norms and values. Upon reviewing their paper, I observed strong parallels to the country, the United Arab Emirates,…

  7. Children's Understanding of Human and Super-Natural Mind

    Science.gov (United States)

    Makris, Nikos; Pnevmatikos, Dimitris

    2007-01-01

    Barrett, Richert, and Driesenga [Barrett, J. L., Richert, R. A., & Driesenga, A. (2001). "God's beliefs versus mother's: The development of nonhuman agents concepts." "Child Development," 72(1), 50-65] have suggested that children are able to conceptualize the representational properties held by certain super-natural entities, such as God, before…

  8. Who's Counted? Who's Counting? Understanding High School Graduation Rates

    Science.gov (United States)

    Pinkus, Lyndsay

    2006-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended and funded to do: enroll, engage, and educate youth to be productive members of society. Graduation rates are not just a "bottom line" for schools--they are critical predictors of individual achievement and have undeniable…

  9. The «Natural Hazard WIKISAURUS»: explanation and understanding of natural hazards to build disaster resilience

    Science.gov (United States)

    Rapisardi, Elena; Di Franco, Sabina; Giardino, Marco

    2013-04-01

    not a unique meaning: e.g. Mercury could stand for the Roman god, the metallic element, the planet, or Freddy the singer. Similarly the word «alert»: in the common language has a certain meaning, whilst in the civil protection framework includes regulations, responsibilities and procedures. The NHW is intended as a collaborative virtual source with validated information on geosciences to support a common understanding of natural hazards, risks and civil protection. The NHW aims to become a point of reference both for acknowledged practitioners, who will share their expertise and data, and for citizens, civil servants, media representatives, and students allowed to comment and contribute to the scientifically validated content. The NHW is a simple tool to support information and communication on natural hazards and civil protection at all levels and would set up a shared and common knowledge. Moreover, NHW could represent the first step of a further challenging programme: through the power of «linked data» NHW could develop and contribute first to a natural hazard semantic, then to a «semantic disaster resilience».

  10. Understanding conflict’s dynamics in participatory natural resources management

    NARCIS (Netherlands)

    Idrissou, L.; Aarts, M.N.C.; Leeuwis, C.; Paassen, van A.

    2018-01-01

    This paper investigated conflicts in participatory protected areas management in Benin to better understand their dynamics. This review paper is based on four articles written from three case-studies of conflicts that emerged and evolved in participatory protected areas management in Benin and a

  11. An APOS analysis of natural science students' understanding of ...

    African Journals Online (AJOL)

    User

    2005), (b) students‟ difficulties with the derivative increase and get worse when the function considered is a composite function ... ing students build appropriate mental structures, and [b] guiding them to apply these structures to construct their understanding of ...... In D Hewitt & A Noyes (eds). Proceedings of the sixth Brit-.

  12. Towards AN Understanding of the Nature of Racial Prejudice

    Science.gov (United States)

    Hoyle, Fred; Wickramasinghe, Chandra

    We discuss a possible biological explanation of the phenomenon of colour prejudice that hinges on the relative advantages and disadvantages in the expression of the strongly dominant gene(s) for melanin under ice-age conditions at different locations on the Earth. An understanding of the genesis of this prejudice could hopefully eradicate or ameliorate its worst manifestations in modern society.

  13. Sustaining salmonid populations: A caring understanding of naturalness of taxa

    Science.gov (United States)

    Nielsen, Jennifer L.; Regier, Henry A.; Knudsen, E. Eric

    2004-01-01

    Species of the family of Salmonidae occur naturally in Northern Hemisphere waters that remain clear and cool to cold in summer. For purposes of reproduction, salmonids generally behaviorally respond to the currents of streams and lakes in recently glaciated areas. For feeding and maturation, many larger species migrate into existing systems of large lakes, seas, and oceans. The subfamilies include Salmoninae, Coregoninae, and Thymallinae. In many locales and regions of the hemisphere, numerous species of these subfamilies evolved and self-organized into species flocks or taxocenes of bewildering complexity. For example, any individual species may play different or unique ecological roles in different taxocenes. The northern Pacific and Atlantic Ocean ecosystems, with their seas and tributaries, each contained a metacomplex of such taxocenes that, in their natural state some centuries ago, resembled each other but differed in many ways. Humans have valued all species of this family for subsistence, ceremonial, naturalist, gustatory, angling, and commercial reasons for centuries. Modern progressive humans (MPHs), whose industrial and commercial enterprises have gradually spread over this hemisphere in recent time, now affect aquatic ecosystems at all scales from local to global. These human effects mingle in complex ways that together induce uniquely natural salmonid taxocenes to disintegrate with the loss of species, including those groups least tolerant to human manipulations, but extending more recently to those taxa more adapted to anthropogenic change. As we leave the modern era, dominated by MPHs, will we find ways to live sustainably with salmonid taxocenes that still exhibit self-organizational integrity, or will only individual, isolated populations of salmonid species, derived from those most tolerant of MPHs, survive? To achieve future sustainability of salmonids, we suggest implementation of a search for intuitive knowledge based on faith in the wisdom of

  14. Understanding relations between pastoralism and its changing natural environment

    OpenAIRE

    Tamou, Charles

    2017-01-01

    The competition for land has become an issue of major concern and cause of conflict, especially between pastoralists and crop farmers, but also between pastoralists and nature conservation institutions. The Biosphere Reserve of W in Benin Republic (WBR) and its surrounding lands are located in the agro-pastoral contact zone in West Africa, enabling competition for land, and affecting the relations between pastoralism and its environment. The general aim of this thesis, therefore, was to under...

  15. Research in Knowledge Representation for Natural Language Understanding

    Science.gov (United States)

    1983-10-01

    of RUS 157 157 160 161 SECTION 9. THE PRAGMATICS OF NON-ANAPHORIC NOUN PHRASES 9.1 Introduction 163 9.2 Setting the Stage: Previous views on... ANAPHORA , ELLIPSIS, DISCOURSE,... MRL DATA BASE TRANSLATOR DBMS COMMAND GENERATOR DBMS COMMANDS FIG. 1 ORGANIZATION OF THE IRUS SYSTEM 146...understanding system (such as semantics, pragmatics , and a dialogue expert) can be used to improve the performance of the parser. The production of the

  16. Determination of dose rates from natural radionuclides in dental materials

    Energy Technology Data Exchange (ETDEWEB)

    Veronese, I. [Dipartimento di Fisica, Universita degli Studi di Milano, Milan (Italy) and INFN, Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milan (Italy)]. E-mail: ivan.veronese@unimi.it; Guzzi, G. [AIRMEB - Italian Association for Metal and Biocompatibility Research, Milan (Italy); Giussani, A. [Dipartimento di Fisica, Universita degli Studi di Milano, Milan (Italy); INFN, Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milan (Italy); Cantone, M.C. [Dipartimento di Fisica, Universita degli Studi di Milano, Milan (Italy); INFN, Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milan (Italy); Ripamonti, D. [Dipartimento di Fisica, Universita degli Studi di Milano, Milan (Italy)

    2006-07-01

    Different types of materials used for dental prosthetics restoration, including feldspathic ceramics, glass ceramics, zirconia-based ceramics, alumina-based ceramics, and resin-based materials, were investigated with regard to content of natural radionuclides by means of thermoluminescence beta dosimetry and gamma spectrometry. The gross beta dose rate from feldspathic and glass ceramics was about ten times higher than the background measurement, whereas resin-based materials generated negligible beta dose rate, similarly to natural tooth samples. The specific activity of uranium and thorium was significantly below the levels found in the period when addition of uranium to dental porcelain materials was still permitted. The high-beta dose levels observed in feldspathic porcelains and glass ceramics are thus mainly ascribable to {sup 4}K, naturally present in these specimens. Although the measured values are below the recommended limits, results indicate that patients with prostheses are subject to higher dose levels than other members of the population. Alumina- and zirconia-based ceramics might be a promising alternative, as they have generally lower beta dose rates than the conventional porcelain materials. However, the dosimetry results, which imply the presence of inhomogeneously distributed clusters of radionuclides in the sample matrix, and the still unsuitable structural properties call for further optimization of these materials.

  17. Understanding vaccination rates and attitudes among patients with rheumatoid arthritis.

    Science.gov (United States)

    Sandler, Diana S; Ruderman, Eric M; Brown, Tiffany; Lee, Ji Young; Mixon, Amanda; Liss, David T; Baker, David W

    2016-03-01

    Appropriate vaccinations are important for patients with rheumatoid arthritis (RA), who are often treated with highly immunosuppressive therapies that increase their risk of infection. However, rates of vaccination among patients with RA are below optimal levels. We conducted a patient survey to assess self-reported vaccination status and to compare that status with electronic health record (EHR) data. We recruited randomly selected patients with RA in an academic practice in 2013. Eligible participants had a diagnosis of RA, at least 1 visit to a rheumatology clinic in each of the previous 2 years, were 18 years or older, and had English listed as their preferred language. The survey included the following domains: a) patient self-reported receipt of influenza, pneumococcal (PNVX), and herpes zoster (HZVX) vaccinations; b) attitudes about these vaccines, including reasons for unvaccinated status, if applicable; and c) provider recommendations about these vaccines. Based on participants' self-report, we found a high vaccination rate for influenza during the previous season (79.4%), a moderate rate of any previous vaccination for pneumococcus (53.9%), and a very low rate of any previous vaccination for herpes zoster (7.8%). If we assume that all self-reports are accurate and we include vaccinations recorded in the EHR that were not reported by patients, the vaccination rates were approximately 8% to 9% higher for PNVX and HZVX. Vaccination rates are low among patients with RA based on self-report data. Further research is needed to investigate system-level barriers to vaccination and the impact of evidence-based, provider-level interventions on vaccination rates.

  18. From the Cover: Understanding nature's design for a nanosyringe

    Science.gov (United States)

    Lopez, Carlos F.; Nielsen, Steve O.; Moore, Preston B.; Klein, Michael L.

    2004-03-01

    Synthetic and natural peptide assemblies can possess transport or conductance activity across biomembranes through the formation of nanopores. The fundamental mechanisms of membrane insertion necessary for antimicrobial or synthetic pore formation are poorly understood. We observe a lipid-assisted mechanism for passive insertion into a model membrane from molecular dynamics simulations. The assembly used in the study, a generic nanotube functionalized with hydrophilic termini, is assisted in crossing the membrane core by transleaflet lipid flips. Lipid tails occlude a purely hydrophobic nanotube. The observed insertion mechanism requirements for hydrophobic-hydrophilic matching have implications for the design of synthetic channels and antibiotics.

  19. Dilemmas in examining understanding of nature of science in Vietnam

    Science.gov (United States)

    Hatherley-Greene, Peter

    2017-06-01

    The two authors, Thi Phuong Thao-Do and Chokchai Yuenyong, explored the Nature of Science as it is understood in Vietnam, a fast-developing `ancient' and modern country which continues to be shaped by uniquely Asian social norms and values. Upon reviewing their paper, I observed strong parallels to the country, the United Arab Emirates, where I have lived and worked for 20 years. In this forum piece, I described several areas of similarity and one striking area of difference between the two societies.

  20. A Thai pre-service teacher's understanding of nature of science in biology teaching

    Science.gov (United States)

    Srisawat, Akkarawat; Aiemsum-ang, Napapan; Yuenyong, Chokchai

    2018-01-01

    This study was conducted on the effect of understanding and instruction of the nature of science of Ms. Wanida, a pre-service student under science education program in biology, Faculty of Education, Khon Kaen University. Wanida was a teaching practicum student majoring in biology at Khon Kaen University Demonstration School (Modindaeng). She was teaching biology for 38 Grade 10 students. Methodology regarded interpretive paradigm. The study aimed to examine 1) Wanida's understanding of the nature of science, 2) Wanida's instruction of the nature of science, 3 students' understanding of the nature of science from Wanida's instruction, and 4) the effects of Wanida's understanding and instruction of the nature of science on students' understanding of the nature of science from Wanida's instruction. Tools of interpretation included teaching observation, a semi-structured interview, open-ended questionnaire, and an observation record form for the instruction of the nature of science. The data obtained was interpreted, encoded, and classified, using the descriptive statistics. The findings indicated that Wanida held good understanding of the nature of science. She could apply the deficient nature of science approach mostly, followed by the implicit nature of science approach. Unfortunately, she could not show her teaching as explicit nature of science. However, her students' the understanding of the nature of science was good.

  1. Understanding natural moisturizing mechanisms: implications for moisturizer technology.

    Science.gov (United States)

    Chandar, Prem; Nole, Greg; Johnson, Anthony W

    2009-07-01

    Dry skin and moisturization are important topics because they impact the lives of many individuals. For most individuals, dry skin is not a notable concern and can be adequately managed with current moisturizing products. However, dry skin can affect the quality of life of some individuals because of the challenges of either harsh environmental conditions or impaired stratum corneum (SC) dry skin protection processes resulting from various common skin diseases. Dry skin protection processes of the SC, such as the development of natural moisturizing factor (NMF), are complex, carefully balanced, and easily perturbed. We discuss the importance of the filaggrin-NMF system and the composition of NMF in both healthy and dry skin, and also reveal new insights that suggest the properties required for a new generation of moisturizing technologies.

  2. Contribution of natural tracers for understanding transfers through argillaceous formations

    International Nuclear Information System (INIS)

    Bensenouci, F.

    2010-01-01

    This study is part of a research programme conducted by IRSN on the safety of deep geological disposal of high level and intermediate long-lived radioactive wastes. It more especially concerns the geological medium considered as a full component of the multi-barrier concept proposed by Andra for a deep repository. Indeed, the Callovo-Oxfordian argillite of the Paris Basin, in the east of France, is being investigated by Andra as a potential host rock for this repository. Performance assessment of this natural barrier is based on the knowledge of its confinement properties and therefore on phenomena possibly involved in the mass transport of radionuclides. In this context, this work aimed at studying the distribution of tracers naturally present in pore waters obtained from boreholes having crossed Mesozoic sedimentary series involving impervious and compacted clay rocks in the East (Andra borehole, EST433) and south of France (IRSN boreholes). Radial diffusion and vapour exchange methods were used to calculate the concentrations and diffusion parameters of the studied tracers. In Tournemire formations, the different profiles describe a curved shapes attributed to a diffusive exchange between the argillite pore water and the surrounding aquifers. Concerning the Mesozoic formations crossed by EST433, the study of the different profiles confirms the diffusion as the dominant transport mechanism in the Callovo-Oxfordian formation, and permits identifying the transport processes in the whole studied column from the Oxfordian formations down to the Liassic one. This study also helps to identify the Liassic formations as a major source of salinity of the Dogger aquifer

  3. An APOS analysis of natural science students' understanding of derivatives

    Directory of Open Access Journals (Sweden)

    Aneshkumar Maharaj

    2013-01-01

    Full Text Available This article reports on a study which used the APOS (action-process-object-schema theoretical framework to investigate university students' understanding of derivatives and their applications. Research was done at the Westville Campus of the University of KwaZulu-Natal in South Africa. The relevant rules for finding derivatives and their applications were taught to undergraduate science students. This paper reports on the analysis of students' responses to six types of questions on derivatives and their applications. The findings of this study suggest that those students had difficulty in applying the rules for derivatives and this was possibly the result of many students not having appropriate mental structures at the process, object and schema levels.

  4. Mucosal vaccines: recent progress in understanding the natural barriers.

    Science.gov (United States)

    Borges, Olga; Lebre, Filipa; Bento, Dulce; Borchard, Gerrit; Junginger, Hans E

    2010-02-01

    It has long been known that protection against pathogens invading the organism via mucosal surfaces correlates better with the presence of specific antibodies in local secretions than with serum antibodies. The most effective way to induce mucosal immunity is to administer antigens directly to the mucosal surface. The development of vaccines for mucosal application requires antigen delivery systems and immunopotentiators that efficiently facilitate the presentation of the antigen to the mucosal immune system. This review provides an overview of the events within mucosal tissues that lead to protective mucosal immune responses. The understanding of those biological mechanisms, together with knowledge of the technology of vaccines and adjuvants, provides guidance on important technical aspects of mucosal vaccine design. Not being exhaustive, this review also provides information related to modern adjuvants, including polymeric delivery systems and immunopotentiators.

  5. Dilemmas in examining understanding of nature of science in Vietnam

    Science.gov (United States)

    Thao-Do, Thi Phuong; Yuenyong, Chokchai

    2017-06-01

    Scholars proved nature of science (NOS) has made certain contributions to science teaching and learning. Nonetheless, what, how and how much NOS should be integrated in the science curriculum of each country cannot be a benchmark, due to the influence of culture and society. Before employing NOS in a new context, it should be carefully studied. In assessing views of NOS in Vietnam, a developing country with Eastern culture where the NOS is not consider a compulsory learning outcome, there are several issues that researchers and educators should notice to develop an appropriate instrument that can clearly exhibit a NOS view of Vietnamese. They may include: time for the survey; length, content, type, and terms of the questionnaire; Vietnamese epistemology and philosophy; and some other Vietnamese social and cultural aspects. The most important reason for these considerations is that a Vietnamese view of NOS and NOS assessment possibly differs from the Western ideas due to the social and cultural impact. As a result, a Western assessment tool may become less effective in an Eastern context. The suggestions and implications in this study were derived from a prolonged investigation on Vietnamese science teacher educators and student teachers of School of Education, at Can Tho University, a State University in Mekong Delta region, Vietnam.

  6. Estimation of erosion rate using natural isotop 137Cs

    International Nuclear Information System (INIS)

    Suhartini, Nita; Milne A T; Wai, Zin Oo

    1998-01-01

    The investigation of erosion rate using natural isotope 137 Cs had been done in hilliness area at GOULBURN-NWS-Australia. The presentation of 137 Cs in natural was as a result of nuclear weapon testing in the middle of 1950's. Fallout of 137 Cs input, when it reached the ground, it rapidly adsorbed at the soil. 137 Cs bind very strong at the fine soil, so it can be used as tracer in the study of soil movement. Soil samples were taken using coring device (di=10 cm, h=20 cm), and were brought to laboratorium for short commun analysis. The preparation are drying, weighing, crushing and sieving. The 137 Cs content of fine samples that pass the 1 mm sieve were analyzed using gamma-spectrometer. The total erosion rate was calculate by ploting the 137 Cs values in the topography map of study area. The result showed that erosion was very low, and total erosion rate is 130 kg/ha.y. (authors)

  7. Understanding the nature of nuclear power plant risk

    International Nuclear Information System (INIS)

    Denning, R. S.

    2012-01-01

    This paper describes the evolution of understanding of severe accident consequences from the non-mechanistic assumptions of WASH-740 to WASH-1400, NUREG-1150, SOARCA and today in the interpretation of the consequences of the accident at Fukushima. As opposed to the general perception, the radiological human health consequences to members of the Japanese public from the Fukushima accident will be small despite meltdowns at three reactors and loss of containment integrity. In contrast, the radiation-related societal impacts present a substantial additional economic burden on top of the monumental task of economic recovery from the nonnuclear aspects of the earthquake and tsunami damage. The Fukushima accident provides additional evidence that we have mis-characterized the risk of nuclear power plant accidents to ourselves and to the public. The human health risks are extremely small even to people living next door to a nuclear power plant. The principal risk associated with a nuclear power plant accident involves societal impacts: relocation of people, loss of land use, loss of contaminated products, decontamination costs and the need for replacement power. Although two of the three probabilistic safety goals of the NRC address societal risk, the associated quantitative health objectives in reality only address individual human health risk. This paper describes the types of analysis that would address compliance with the societal goals. (authors)

  8. Learner Characteristics and Understanding Nature of Science. Is There an Association?

    Science.gov (United States)

    Çetinkaya-Aydın, Gamze; Çakıroğlu, Jale

    2017-11-01

    The purpose of this study was to investigate the possible associations between preservice science teachers' understanding of nature of science and their learner characteristics; understanding of nature of scientific inquiry, science teaching self-efficacy beliefs, metacognitive awareness level, and faith/worldview schemas. The sample of the current study was 60 3rd-year preservice science teachers enrolled in the Nature of Science and History of Science course. Using a descriptive and associational case study design, data were collected by means of different qualitative and quantitative questionnaires. Analysis of the data revealed that preservice science teachers' understanding of nature of science and nature of scientific inquiry were highly associated. Similarly, science teaching self-efficacy beliefs, metacognitive awareness levels, and faith/worldviews of the preservice science teachers were found to be significantly associated with their understanding of nature of science. Thus, it can be concluded that there might be other factors interfering with the learning processes of nature of science.

  9. The Natural Rate of Unemployment and its Implications for Economic Policy

    Directory of Open Access Journals (Sweden)

    Monica DOBRESCU

    2011-02-01

    Full Text Available The analysis of the inflation-unemployment tradeoff has undergone several stages during the post-war era. The first was marked by the acceptance of A.W. Phillips’ 1957 hypothesis and the subsequent Phillips curve. The next stage – marked by Friedman’s contributions – revealed a vertical long-run Phillips curve and introduced the natural rate of unemployment, designating that level of unemployment consistent with stable inflation. This paper explores the theoretical and empirical implications that have emerged since the introduction of the natural rate concept. At the theoretical level, we find that, far from questioning its existence, the theoretical debates revolve around two main questions: Can we actually determine the precise level of the natural rate and what are the appropriate techniques? and How does the natural rate change over time and what are the factors that influence it? Empirical knowledge, on the other hand, lags behind. Despite numerous empirical studies, economists are a long way from an appropriate quantitative understanding of the determinants and variability of the natural rate, either across time or across countries.

  10. Natural radioactivity and radon specific exhalation rate of zircon sands

    International Nuclear Information System (INIS)

    Righi, S.; Verita, S.; Bruzzi, L.; Albertazzi, A.

    2006-01-01

    The study focuses on the radon emanation from zircon sands and their derivatives, which are widely used in many sectors of industry. In particular, the results obtained by experimental measurements on samples of zircon sands and zircon flours commonly used in Italian ceramic industries are reported. Zircon sands contain a significant concentration of natural radioactivity because Th and U may substitute zirconium in the zircon crystal lattice. The relevant routes of exposure of workers to T.E.N.O.R.M. from zircon materials are external radiation and internal exposure, either by inhalation of aerosols in dusty working conditions or by inhalation of radon in workplaces. The main objective of this investigation is to provide experimental data able to better calculate the internal exposure of workers due to radon inhalation. Zircon samples were surveyed for natural radioactivity, radon specific exhalation rate and emanation fraction. Measurements of radioactivity concentration were carried out using γ-spectrometry. Methods used for determining radon consisted in determining the 222 Rn activity accumulated in a vessel after a given accumulation build-up time. The average activity concentrations of 238 U and 232 Th in samples result about 2600 and 550 Bq kg-1, respectively; these concentrations are significantly higher than the world average noticed in soils, rocks and Earth crust. The 222 Rn specific exhalation rates result very low probably due to the low porosity of the material and the consequent difficulty for radon to be released from the zircon crystal lattice. (author)

  11. Learner Characteristics and Understanding Nature of Science: Is There an Association?

    Science.gov (United States)

    Çetinkaya-Aydin, Gamze; Çakiroglu, Jale

    2017-01-01

    The purpose of this study was to investigate the possible associations between preservice science teachers' understanding of nature of science and their learner characteristics; understanding of nature of scientific inquiry, science teaching self-efficacy beliefs, metacognitive awareness level, and faith/worldview schemas. The sample of the…

  12. Mathematical understanding of nature essays on amazing physical phenomena and their understanding by mathematicians

    CERN Document Server

    Arnold, V I

    2014-01-01

    This collection of 39 short stories gives the reader a unique opportunity to take a look at the scientific philosophy of Vladimir Arnold, one of the most original contemporary researchers. Topics of the stories included range from astronomy, to mirages, to motion of glaciers, to geometry of mirrors and beyond. In each case Arnold's explanation is both deep and simple, which makes the book interesting and accessible to an extremely broad readership. Original illustrations hand drawn by the author help the reader to further understand and appreciate Arnold's view on the relationship between math

  13. Understanding people's ideas on natural resource management : research on social representations of nature

    NARCIS (Netherlands)

    Buijs, A.E.; Hovardas, T.; Figari, H.; Castro, P.; Devine-Wright, P.; Fischer, A.; Mouro, C.; Selge, S.

    2012-01-01

    Ongoing fragmentation between social groups on the appropriate targets and relevant actors for nature conservation signals the need for further advancements in theorizing about the human–nature interaction. Through a focus on the complexity of social thought and confrontations between social groups,

  14. Prediction of Mass Flow Rate in Supersonic Natural Gas Processing

    Directory of Open Access Journals (Sweden)

    Wen Chuang

    2015-11-01

    Full Text Available The mass flow rate of natural gas through the supersonic separator was numerically calculated by various cubic equations of state. The numerical results show that the compressibility factor and specific heat ratio for ideal gas law diverge remarkably from real gas models at a high inlet pressure. Simultaneously, the deviation of mass flow calculated by the ideal and real gas models reaches over 10 %. The difference increases with the lower of the inlet temperature regardless of the inlet pressure. A higher back pressure results in an earlier location of the shock wave. The pressure ratio of 0.72 is the first threshold to get the separator work normally. The second threshold is 0.95, in which case the whole flow is subsonic and cannot reach the choked state. The shock position moves upstream with the real gas model compared to the ideal gas law in the cyclonic separation section.

  15. The natural radionuclide concentration and radon exhalation rate of Turkish natural stones

    International Nuclear Information System (INIS)

    Yasar, O.; Yaprak, G.; Guer, F.

    2006-01-01

    Geological materials usually contaminated with naturally occurring radioactive materials (NORM) have become a focus great attention. These NORM under certain conditions can reach hazardous contamination levels. Some contamination levels may be sufficiently severe that precautions must be taken. The Turkey has very important natural stones potential with over 5 billion m 3 marble reserves. According to 2002 giving data the number of Turkish stones export is 303 million US Dollars. In this regards, the present study deals with 120 Turkish natural stones. The studied samples were analyzed and the concentrations in Bq/kg dry weight of radioisotopes were determined by gamma-ray spectrometry using HPGe defector in Bq/kg dry weight. For the measurement of the radon exhalation rate, the 'can technique' using sensitive alpha sensitive LR-115 type II plastic defectors were used. The radium equivalent activity varied from 285 Bq/kg to 325 Bq/kg for granite samples and from 2 Bq/kg to 32 Bq/kg for marble samples. The value of radon exhalation rate ranged from 0.06 Bq/m 2 h - 1 to 0.46 Bq/m 2 h - 1 for garnite samples and from 0.006 Bq/m 2 h - 1 to 0.011 Bq/m 2 h - 1 for marble samples. According to the recommended values and the calculated external hazard index values the samples are acceptable for use as building materials and decoration

  16. Entropy: A Unifying Path for Understanding Complexity in Natural, Artificial and Social Systems

    Science.gov (United States)

    2011-07-01

    us now address complex systems which include a substantial social component. We may start with economics and theory of finance. Given the long memory ...Entropy: A Unifying Path for Understanding Complexity in Natural, Artificial and Social Systems * Constantino Tsallis Centro Brasileiro de...Path for Understanding Complexity in Natural, Artificial and Social Systems 5a. CONTRACT NUMBER FA23861114006 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  17. Natural Language Understanding Systems Within the A. I. Paradigm: A Survey and Some Comparisons.

    Science.gov (United States)

    Wilks, Yorick

    The paper surveys the major projects on the understanding of natural language that fall within what may now be called the artificial intelligence paradigm of natural language systems. Some space is devoted to arguing that the paradigm is now a reality and different in significant respects from the generative paradigm of present-day linguistics.…

  18. Prospective Elementary Teachers' Understanding of the Nature of Science and Perceptions of the Classroom Learning Environment

    Science.gov (United States)

    Martin-Dunlop, Catherine S.

    2013-01-01

    This study investigated prospective elementary teachers' understandings of the nature of science and explored associations with their guided-inquiry science learning environment. Over 500 female students completed the Nature of Scientific Knowledge Survey (NSKS), although only four scales were analyzed-Creative, Testable, Amoral, and Unified. The…

  19. Physical nature of strain rate sensitivity of metals and alloys at high strain rates

    Science.gov (United States)

    Borodin, E. N.; Gruzdkov, A. A.; Mayer, A. E.; Selyutina, N. S.

    2018-04-01

    The role of instabilities of plastic flow at plastic deformation of various materials is one of the important cross-disciplinary problems which is equally important in physics, mechanics and material science. The strain rate sensitivities under slow and high strain rate conditions of loading have different physical nature. In the case of low strain rate, the sensitivity arising from the inertness of the defect structures evolution can be expressed by a single parameter characterizing the plasticity mechanism. In our approach, this is the value of the characteristic relaxation time. In the dynamic case, there are additional effects of “high-speed sensitivity” associated with the micro-localization of the plastic flow near the stress concentrators. In the frames of mechanical description, this requires to introduce additional strain rate sensitivity parameters, which is realized in numerous modifications of Johnson–Cook and Zerilli–Armstrong models. The consideration of both these factors is fundamental for an adequate description of the problems of dynamic deformation of highly inhomogeneous metallic materials such as steels and alloys. The measurement of the dispersion of particle velocities on the free surface of a shock-loaded material can be regarded as an experimental expression of the effect of micro-localization. This is also confirmed by our results of numerical simulation of the propagation of shock waves in a two-dimensional formulation and analytical estimations.

  20. Examining Preservice Science Teacher Understanding of Nature of Science: Discriminating Variables on the Aspects of Nature of Science

    Science.gov (United States)

    Jones, William I.

    This study examined the understanding of nature of science among participants in their final year of a 4-year undergraduate teacher education program at a Midwest liberal arts university. The Logic Model Process was used as an integrative framework to focus the collection, organization, analysis, and interpretation of the data for the purpose of (1) describing participant understanding of NOS and (2) to identify participant characteristics and teacher education program features related to those understandings. The Views of Nature of Science Questionnaire form C (VNOS-C) was used to survey participant understanding of 7 target aspects of Nature of Science (NOS). A rubric was developed from a review of the literature to categorize and score participant understanding of the target aspects of NOS. Participants' high school and college transcripts, planning guides for their respective teacher education program majors, and science content and science teaching methods course syllabi were examined to identify and categorize participant characteristics and teacher education program features. The R software (R Project for Statistical Computing, 2010) was used to conduct an exploratory analysis to determine correlations of the antecedent and transaction predictor variables with participants' scores on the 7 target aspects of NOS. Fourteen participant characteristics and teacher education program features were moderately and significantly ( p Middle Childhood with a science concentration program major or in the Adolescent/Young Adult Science Education program major were more likely to have an informed understanding on each of the 7 target aspects of NOS. Analyses of the planning guides and the course syllabi in each teacher education program major revealed differences between the program majors that may account for the results.

  1. Heteroaggregation and sedimentation rates for nanomaterials in natural waters

    NARCIS (Netherlands)

    Quik, J.T.K.; Velzeboer, I.; Wouterse, M.; Koelmans, A.A.; Meent, van de D.

    2014-01-01

    Exposure modeling of engineered nanomaterials requires input parameters such as sedimentation rates and heteroaggregation rates. Here, we estimate these rates using quiescent settling experiments under environmentally relevant conditions. We investigated 4 different nanomaterials (C60, CeO2, SiO2-Ag

  2. The understanding of the students about the nature of light in recursive curriculum

    Directory of Open Access Journals (Sweden)

    Geide Rosa Coelho

    2010-01-01

    Full Text Available We report an inquiry on the development of students' understanding about the nature of light. The study happened in a learning environment with a recursive and spiral Physics syllabus. We investigated the change in students' understanding about the nature of light during their 3rd year in High School, and the level of understanding about this subject achieved by students at the end of this year. To assess the students' understanding, we developed an open questionnaire form and a set of hierarchical categories, consisting of five different models about the nature of light. The questionnaire was used to access the students´ understanding at the beginning and at the end of the third level of the recursive curriculum. The results showed that students have a high level of prior knowledge, and also that the Physics learning they experienced had enhanced their understanding, despite the effects are not verified in all the Physics classes. By the end of the third year, most of the students explain the nature of light using or a corpuscular electromagnetic model or a dual electromagnetic model, but some students use these models with inconsistencies in their explanations.

  3. Understandings of Nature of Science and Multiple Perspective Evaluation of Science News by Non-science Majors

    Science.gov (United States)

    Leung, Jessica Shuk Ching; Wong, Alice Siu Ling; Yung, Benny Hin Wai

    2015-10-01

    Understandings of nature of science (NOS) are a core component of scientific literacy, and a scientifically literate populace is expected to be able to critically evaluate science in the media. While evidence has remained inconclusive on whether better NOS understandings will lead to critical evaluation of science in the media, this study aimed at examining the correlation therein. Thirty-eight non-science majors, enrolled in a science course for non-specialists held in a local community college, evaluated three health news articles by rating the extent to which they agreed with the reported claims and providing as many justifications as possible. The majority of the participants were able to evaluate and justify their viewpoint from multiple perspectives. Students' evaluation was compared with their NOS conceptions, including the social and cultural embedded NOS, the tentative NOS, the peer review process and the community of practice. Results indicated that participants' understanding of the tentative NOS was significantly correlated with multiple perspective evaluation of science news reports of socioscientific nature (r = 0.434, p media of socioscientific nature. However, the null result for other target NOS aspects in this study suggested a lack of evidence to assume that understanding the social dimensions of science would have significant influence on the evaluation of science in the media. Future research on identifying the reasons for why and why not NOS understandings are applied in the evaluation will move this field forward.

  4. High recombination rate in natural populations of Plasmodium falciparum

    NARCIS (Netherlands)

    Conway, D. J.; Roper, C.; Oduola, A. M.; Arnot, D. E.; Kremsner, P. G.; Grobusch, M. P.; Curtis, C. F.; Greenwood, B. M.

    1999-01-01

    Malaria parasites are sexually reproducing protozoa, although the extent of effective meiotic recombination in natural populations has been debated. If meiotic recombination occurs frequently, compared with point mutation and mitotic rearrangement, linkage disequilibrium between polymorphic sites is

  5. Tensile behaviour of natural fibres. Effect of loading rate, temperature and humidity on the “accommodation” phenomena

    Directory of Open Access Journals (Sweden)

    Placet V.

    2010-06-01

    Full Text Available The use of natural fibres in high performance composite requires an accurate understanding of the mechanical behaviour of the fibres themselves. As for all biobased materials, the mechanical properties of natural fibres depend generally on the testing rate and on the environmental conditions. In addition, natural fibres as hemp for example exhibit a particular mechanism of stiffness increase and accommodation phenomena under cyclic loading. Loading rate, temperature and humidity effects on the viscoelastic properties of hemp fibres were investigated in this work. The collected results clearly emphasis the involvement of time-dependant and mechano-sorptive mechanisms.

  6. Estimating inbreeding rates in natural populations: Addressing the problem of incomplete pedigrees

    Science.gov (United States)

    Miller, Mark P.; Haig, Susan M.; Ballou, Jonathan D.; Steel, E. Ashley

    2017-01-01

    Understanding and estimating inbreeding is essential for managing threatened and endangered wildlife populations. However, determination of inbreeding rates in natural populations is confounded by incomplete parentage information. We present an approach for quantifying inbreeding rates for populations with incomplete parentage information. The approach exploits knowledge of pedigree configurations that lead to inbreeding coefficients of F = 0.25 and F = 0.125, allowing for quantification of Pr(I|k): the probability of observing pedigree I given the fraction of known parents (k). We developed analytical expressions under simplifying assumptions that define properties and behavior of inbreeding rate estimators for varying values of k. We demonstrated that inbreeding is overestimated if Pr(I|k) is not taken into consideration and that bias is primarily influenced by k. By contrast, our new estimator, incorporating Pr(I|k), is unbiased over a wide range of values of kthat may be observed in empirical studies. Stochastic computer simulations that allowed complex inter- and intragenerational inbreeding produced similar results. We illustrate the effects that accounting for Pr(I|k) can have in empirical data by revisiting published analyses of Arabian oryx (Oryx leucoryx) and Red deer (Cervus elaphus). Our results demonstrate that incomplete pedigrees are not barriers for quantifying inbreeding in wild populations. Application of our approach will permit a better understanding of the role that inbreeding plays in the dynamics of populations of threatened and endangered species and may help refine our understanding of inbreeding avoidance mechanisms in the wild.

  7. Prospective Elementary Teachers' Understanding of the Nature of Science and Perceptions of the Classroom Learning Environment

    Science.gov (United States)

    Martin-Dunlop, Catherine S.

    2013-06-01

    This study investigated prospective elementary teachers' understandings of the nature of science and explored associations with their guided-inquiry science learning environment. Over 500 female students completed the Nature of Scientific Knowledge Survey (NSKS), although only four scales were analyzed-Creative, Testable, Amoral, and Unified. The learning environment was assessed using previously-validated and reliable scales from What Is Happening In this Class? (WIHIC) and the Science Laboratory Environment Inventory (SLEI). Analyses indicated moderate multiple correlations that were statistically significant ( p Creative (R = 0.22), Testable (R = 0.29), and Unified (R = 0.27), and a positive learning environment. Regression coefficients revealed that Open-Endedness was a significant independent predictor of students' understanding of the role of creativity in science (β = 0.16), while Cooperation, Open-Endedness, and Material Environment were linked with understanding the testable nature of science (β = 0.10-0.12). Interview questions probed possible relationships between an improved understanding of the nature of science and elements of a positive classroom environment. Responses suggested that an appropriate level of open-endedness during investigations was very important as this helped students grapple with abstract nature of science concepts and shift their conceptions closer to a more realistic view of scientific practice.

  8. Rediscovering nature as commons in environmental planning: new understandings through dialogue

    Directory of Open Access Journals (Sweden)

    Mikaela Vasstrom

    2014-08-01

    Full Text Available A core challenge in environmental planning is the gap between a strong participatory ethos and top-down defined nature protection policies. Nature protection policies for large areas are concerned with securing ecological biodiversity and wildlife habitats against increasing societal claims. Such planning objectives also affect the socio-economic and cultural relations between the local community and the area they live in, and raise conflicts between local and national protection objectives and steering levels. Despite attempts to facilitate participatory planning approaches as a means of reducing conflict, nature protection continues to be contested in local communities. This paper explores the different understandings of nature at play between citizens and planning authorities throughout a habitat protection planning process in Norway. The paper discusses whether environmental planning of large spatial areas could develop communication arenas designed to deliberate different understandings of an area as a matter of commons between institutional planning perspectives of nature protection and (local understandings of the area as part of everyday life. The paper sheds light on how large spatial areas are understood at different government levels and from everyday life orientations, and how these could be used to develop mutual understandings of the area as a common.

  9. Natural conception rates in subfertile couples following fertility awareness training.

    Science.gov (United States)

    Frank-Herrmann, P; Jacobs, C; Jenetzky, E; Gnoth, C; Pyper, C; Baur, S; Freundl, G; Goeckenjan, M; Strowitzki, T

    2017-04-01

    To analyze cumulative pregnancy rates of subfertile couples after fertility awareness training. A prospective observational cohort study followed 187 subfertile women, who had received training in self-observation of the fertile phase of the menstrual cycle with the Sensiplan method, for 8 months. The women, aged 21-47 years, had attempted to become pregnant for 3.5 years on average (range 1-8 years) before study entry. Amenorrhea, known tubal occlusion and severe male factor had been excluded. An additional seven women, who had initially been recruited, became pregnant during the cycle immediately prior to Sensiplan training: this is taken to be the spontaneous pregnancy rate per cycle in the cohort in the absence of fertility awareness training. The cumulative pregnancy rate of subfertile couples after fertility awareness training was 38% (95% CI 27-49%; 58 pregnancies) after eight observation months, which is significantly higher than the estimated basic pregnancy rate of 21.6% in untrained couples in the same cohort. For couples who had been seeking to become pregnant for 1-2 years, the pregnancy rate increased to 56% after 8 months. A female age above 35 (cumulative pregnancy rate 25%, p = 0.06), couples who had attempted to become pregnant for more than 2 years (cumulative pregnancy rate 17%, p therapy in the management of subfertility.

  10. Star-formation rates of cluster galaxies: nature versus nurture

    Science.gov (United States)

    Laganá, Tatiana F.; Ulmer, M. P.

    2018-03-01

    We analysed 17 galaxy clusters, and investigated, for the first time, the dependence of the star formation rate (SFR) and specific star formation rate (sSFR) as a function of projected distance (as a proxy for environment) and stellar mass for cluster galaxies in an intermediate-to-high redshift range (0.4 cluster galaxies at an intermediate-to-high redshift range, mass is the primary characteristic that drives SFR.

  11. Understanding learning in natural resource management : experiences with a contextualised responsive evaluation approach

    NARCIS (Netherlands)

    Kouévi, T.A.

    2013-01-01

    This dissertation may be located in the wide debate on the effectiveness of policy interventions in developing countries, in the field of natural resource management (NRM). It is especially concerned with contributing to the understanding of the limited effectiveness of fishery management

  12. Understanding the Nature of Science and Scientific Progress: A Theory-Building Approach

    Science.gov (United States)

    Chuy, Maria; Scardamalia, Marlene; Bereiter, Carl; Prinsen, Fleur; Resendes, Monica; Messina, Richard; Hunsburger, Winifred; Teplovs, Chris; Chow, Angela

    2010-01-01

    In 1993 Carey and Smith conjectured that the most promising way to boost students' understanding of the nature of science is a "theory-building approach to teaching about inquiry." The research reported here tested this conjecture by comparing results from two Grade 4 classrooms that differed in their emphasis on and technological…

  13. Lost in Transition: Secondary School Students' Understanding of Landscapes and Natural Resource Management

    Science.gov (United States)

    Kruger, Tarnya; Beilin, Ruth

    2012-01-01

    In 2007, a study titled "Living in the landscapes of the 21st century" was conducted in 11 high schools in metropolitan and rural Victoria. The research team investigated Year 10 students' conceptions of landscapes in order to explore their understandings of natural resource management (NRM), including agriculture, food, land and water…

  14. Enhancing Laos Students' Understanding of Nature of Science in Physics Learning about Atom for Peace

    Science.gov (United States)

    Sengdala, Phoxay; Yuenyong, Chokchai

    2014-01-01

    This paper aimed to study of Grade 12 students' understanding of nature of science in learning about atom for peace through science technology and society (STS) approach. Participants were 51 Grade 12 who study in Thongphong high school Vientiane Capital City Lao PDR, 1st semester of 2012 academic year. This research regarded interpretive…

  15. Understanding Nature-Related Behaviors among Children through a Theory of Reasoned Action Approach

    Science.gov (United States)

    Gotch, Chad; Hall, Troy

    2004-01-01

    The Theory of Reasoned Action has proven to be a valuable tool for predicting and understanding behavior and, as such, provides a potentially important basis for environmental education program design. This study used a Theory of Reasoned Action approach to examine a unique type of behavior (nature-related activities) and a unique population…

  16. Understanding learning in natural resource management : experiences with a contextualised responsive evaluation approach

    NARCIS (Netherlands)

    Kouévi, T.A.

    2013-01-01

    This dissertation may be located in the wide debate on the effectiveness of policy interventions in developing countries, in the field of natural resource management (NRM). It is especially concerned with contributing to the understanding of the limited effectiveness of fishery management

  17. Understanding the Nature of Learners' Out-of-Class Language Learning Experience with Technology

    Science.gov (United States)

    Lai, Chun; Hu, Xiao; Lyu, Boning

    2018-01-01

    Out-of-class learning with technology comprises an essential context of second language development. Understanding the nature of out-of-class language learning with technology is the initial step towards safeguarding its quality. This study examined the types of learning experiences that language learners engaged in outside the classroom and the…

  18. Descriptive Understandings of the Nature of Science: Examining the Consensual and Family Resemblance Approaches

    Science.gov (United States)

    do Nascimento Rocha, Maristela; Gurgel, Ivã

    2017-01-01

    This paper performs a critical analysis of the consensual and family resemblance approaches to the nature of science. Despite the debate that surrounds them, between a pragmatic consensus and a more comprehensive understanding, both approaches have in common the goal of helping students to "internalize" knowledge about science in a…

  19. Impacts of Contextual and Explicit Instruction on Preservice Elementary Teachers' Understandings of the Nature of Science

    Science.gov (United States)

    Bell, Randy L.; Matkins, Juanita Jo; Gansneder, Bruce M.

    2011-01-01

    This mixed-methods investigation compared the relative impacts of instructional approach and context of nature of science instruction on preservice elementary teachers' understandings. The sample consisted of 75 preservice teachers enrolled in four sections of an elementary science methods course. Independent variables included instructional…

  20. Understanding How Science Works: The Nature of Science as The Foundation for Science Teaching and Learning

    Science.gov (United States)

    McComas, William F.

    2017-01-01

    The nature of science (NOS) is a phrase used to represent the rules of the game of science. Arguably, NOS is the most important content issue in science instruction because it helps students understand the way in which knowledge is generated and validated within the scientific enterprise. This article offers a proposal for the elements of NOS that…

  1. The Mismatch among Students' Views about Nature of Science, Acceptance of Evolution, and Evolutionary Science Understandings

    Science.gov (United States)

    Cavallo, Ann M. L.; White, Kevin J.; McCall, David

    2011-01-01

    This study explored interrelationships among high school students' views about nature of science (NOS), acceptance of evolution, and conceptual understanding of evolution, and the extent to which these may have shifted from pre- to post-instruction on evolutionary theory. Eighty-one students enrolled in ninth-grade Biology responded to…

  2. Student Teachers' Understanding and Acceptance of Evolution and the Nature of Science

    Science.gov (United States)

    Coleman, Joy; Stears, Michèle; Dempster, Edith

    2015-01-01

    The focus of this study was student teachers at a South African university enrolled in a Bachelor of Education (B.Ed.) programme and a Postgraduate Certificate in Education (PGCE), respectively. The purpose of this study was to explore students' understanding and acceptance of evolution and beliefs about the nature of science (NOS), and to…

  3. The main natural lows of high-rate coal pyrolysis

    Directory of Open Access Journals (Sweden)

    Chemyavsky Nikola V.

    2003-01-01

    Full Text Available The importance of coal pyrolysis studies for the development of energy technologies is evident, since pvrolysis is the first stage of any process of coal thermal conversion. In combustion, pyrolysis determines conditions of coal ignition and the rate of char after-burning, in gasification, pyrolysis determines total yield of gasification products. It must be noted that in modern energy technologies pyrolysis occurs at high late of coal particle heating (=10 K/s for different fluidized bed, or FB-technologies or super-high-rate (>10**5 K/s for entrained-flow gasification, and in some of them at high pressure. In CETI during last 12 years the detailed study of pyrolysis in FB laboratory-scale PYROLYSIS-D plant and entramed-flow pilot-scale GSP-01 plant, was carried out. In this paper main results of mentioned investigations are given. Kinetic constants for bituminous coals and anthracite high heating rates in entrained flow for high temperatures (>1500 °C and >1900 °C, and in fluidized bed conditions in temperature range 972-1273 K. In order to describe data obtained in fluidized bed conditions, G--model based method of calculation of devolatization dynamics was suited to FB heating conditions. Calculated and experimental kinetic data are in good agreement. The result proves that at FB-pvrolysis conditions intrinsic mass-transfer limitations are negligible and devolatilization is really kinetic-controlled.

  4. Thai in-service teacher understanding of nature of science in biology teaching: Case of Mali

    Science.gov (United States)

    Aiemsum-ang, Napapan; Yuenyong, Chokchai

    2018-01-01

    This paper aimed to investigate the existing ideas of nature of science (NOS) teaching in Thailand biology classroom. The study reported the existing ideas of nature of science (NOS) teaching of one biology teacher Mrs. Mali who had been teaching for 6 years at in a school in Khon Kaen city. Methodology regarded interpretive paradigm. Tools of interpretation included 2 months of classroom observation, interviewing, and questionnaire of NOS. The findings revealed Mali held good understanding of the nature of science in the aspect of the use of evidence, the aspect of knowledge inquiry through different observation and deduction, the aspect of creativity and imagination influencing science knowledge inquiry, and the aspect of changeable scientific knowledge. Her biology teaching indicated that she used both the deficient nature of science approach and the implicit nature of science approach. The implicit nature of science approach was applied mostly in 7 periods and only 2 periods were arranged using the deficient nature of science approach. The paper has implication for professional development and pre-service program on NOS teaching in Thailand.

  5. History and Philosophy of Science as a Guide to Understanding Nature of Science

    Directory of Open Access Journals (Sweden)

    Mansoor Niaz

    2016-06-01

    Full Text Available Nature of science (NOS is considered to be a controversial topic by historians, philosophers of science and science educators. It is paradoxical that we all teach science and still have difficulties in understanding what science is and how it develops and progresses. A major obstacle in understanding NOS is that science is primarily ‘unnatural’, that is it cannot be learned by a simple observation of phenomena. In most parts of the world history and philosophy of science are ‘inside’ science content and as such can guide our understanding of NOS. However, some science educators consider the ‘historical turn’ as dated and hence neglect the historical approach and instead emphasize the model based naturalist view of science. The objective of this presentation is to show that the historical approach is very much a part of teaching science and actually complements naturalism. Understanding NOS generally requires two aspects of science: Domain general and domain specific. In the classroom this can be illustrated by discussing the atomic models developed in the early 20th century which constitute the domain specific aspect of NOS. This can then lead to an understanding of the tentative nature of science that is a domain general aspect of NOS. A review of the literature in science education reveals three views (among others of understanding NOS: a Consensus view: It attempts to include only those domain-general NOS aspects that are the least controversial (Lederman, Abd-El-Khalick; b Family resemblance view: Based on the ideas of Wittgenstein, this view promotes science as a cognitive system (Irzik, Nola; c Integrated view: this view postulates that both domain general and domain specific aspects of NOS are not dichotomous but rather need to be integrated and are essential if we want students to understand ‘science in the making’ (Niaz. The following framework helps to facilitate integration: i Elaboration of a theoretical framework

  6. Effect of Conceptual Change Approach on Students' Understanding of Reaction Rate Concepts

    Science.gov (United States)

    Kingir, Sevgi; Geban, Omer

    2012-01-01

    The purpose of the present study was to investigate the effect of conceptual change text oriented instruction compared to traditional instruction on 10th grade students' understanding of reaction rate concepts. 45 students from two classes of the same teacher in a public high school participated in this study. Students in the experimental group…

  7. A Look into Students' Retention of Acquired Nature of Science Understandings

    Science.gov (United States)

    Khishfe, Rola

    2015-07-01

    Having the learning and retention of science content and skills as a goal of scientific literacy, it is significant to study the issue of retention as it relates to teaching and learning about nature of science (NOS). Then, the purpose of this study was to investigate the development of NOS understandings of students, and the retention of these understandings four months after being acquired through explicit reflective instruction in relation to two contexts. Participants were 24 tenth-grade students at a private high school in a city in the Middle East. Explicit NOS instruction was addressed within a six-week unit about genetic engineering. Three NOS aspects were integrated and dispersed across the unit. A questionnaire, together with semi-structured interviews, was administered as pre-, post-, and delayed post-test to assess the retention of participants' NOS understandings. The questionnaire had two open-ended scenarios addressing controversial socioscientific issues about genetically modified food and water fluoridation. Results showed that most students improved their naïve understandings of NOS in relation to the two contexts following the six-week unit with the explicit NOS instruction. However, these newly acquired NOS understandings were not retained by all students four months after instruction. Many of the students reverted back to their earlier naïve understandings. Conclusions about the factors facilitating the process of retention as the orientation to meaningful learning and the prolonged exposure to the domain were discussed in relation to practical implications in the classroom.

  8. Understanding changes over time in workers' compensation claim rates using time series analytical techniques.

    Science.gov (United States)

    Moore, Ian C; Tompa, Emile

    2011-11-01

    The objective of this study is to better understand the inter-temporal variation in workers' compensation claim rates using time series analytical techniques not commonly used in the occupational health and safety literature. We focus specifically on the role of unemployment rates in explaining claim rate variations. The major components of workers' compensation claim rates are decomposed using data from a Canadian workers' compensation authority for the period 1991-2007. Several techniques are used to undertake the decomposition and assess key factors driving rates: (i) the multitaper spectral estimator, (ii) the harmonic F test, (iii) the Kalman smoother and (iv) ordinary least squares. The largest component of the periodic behaviour in workers' compensation claim rates is seasonal variation. Business cycle fluctuations in workers' compensation claim rates move inversely to unemployment rates. The analysis suggests that workers' compensation claim rates between 1991 and 2008 were driven by (in order of magnitude) a strong negative long term growth trend, periodic seasonal trends and business cycle fluctuations proxied by the Ontario unemployment rate.

  9. Erosion rates of wood during natural weathering. Part II, Earlywood and latewood erosion rates

    Science.gov (United States)

    R. Sam Williams; Mark T. Knaebe; William C. Feist

    2001-01-01

    This is the second in a series of reports on the erosion rates of wood exposed outdoors near Madison, Wisconsin. In the work reported here, the erosion rates of earlywood and latewood were determined for smooth-planed vertical-grained lumber for an exposure period of 14 years. The specimens were oriented vertically, facing south; erosion was measured annually for the...

  10. Erosion rates of wood during natural weathering. Part III, Effect of exposure angle on erosion rate

    Science.gov (United States)

    R. Sam Williams; Mark T. Knaebe; James W. Evans; William C. Feist

    2001-01-01

    This is the third in a series of reports on the erosion rates of wood exposed outdoors near Madison, Wisconsin. The specimens were exposed at an orientation of 90* or 45* facing south or horizontally (0*) for 10 years. Erosion was measured annually for the first 8 years and after 10 years. The erosion rates of earlywood (springwood) and latewood (summerwood) were...

  11. Soil Carbon-Fixation Rates and Associated Bacterial Diversity and Abundance in Three Natural Ecosystems.

    Science.gov (United States)

    Lynn, Tin Mar; Ge, Tida; Yuan, Hongzhao; Wei, Xiaomeng; Wu, Xiaohong; Xiao, Keqing; Kumaresan, Deepak; Yu, San San; Wu, Jinshui; Whiteley, Andrew S

    2017-04-01

    CO 2 assimilation by autotrophic microbes is an important process in soil carbon cycling, and our understanding of the community composition of autotrophs in natural soils and their role in carbon sequestration of these soils is still limited. Here, we investigated the autotrophic C incorporation in soils from three natural ecosystems, i.e., wetland (WL), grassland (GR), and forest (FO) based on the incorporation of labeled C into the microbial biomass. Microbial assimilation of 14 C ( 14 C-MBC) differed among the soils from three ecosystems, accounting for 14.2-20.2% of 14 C-labeled soil organic carbon ( 14 C-SOC). We observed a positive correlation between the cbbL (ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large-subunit gene) abundance, 14 C-SOC level, and 14 C-MBC concentration confirming the role of autotrophic bacteria in soil carbon sequestration. Distinct cbbL-bearing bacterial communities were present in each soil type; form IA and form IC RubisCO-bearing bacteria were most abundant in WL, followed by GR soils, with sequences from FO soils exclusively derived from the form IC clade. Phylogenetically, the diversity of CO 2 -fixing autotrophs and CO oxidizers differed significantly with soil type, whereas cbbL-bearing bacterial communities were similar when assessed using coxL. We demonstrate that local edaphic factors such as pH and salinity affect the C-fixation rate as well as cbbL and coxL gene abundance and diversity. Such insights into the effect of soil type on the autotrophic bacterial capacity and subsequent carbon cycling of natural ecosystems will provide information to enhance the sustainable management of these important natural ecosystems.

  12. Challenges and Changes: Developing Teachers' and Initial Teacher Education Students' Understandings of the Nature of Science

    Science.gov (United States)

    Ward, Gillian; Haigh, Mavis

    2017-12-01

    Teachers need an understanding of the nature of science (NOS) to enable them to incorporate NOS into their teaching of science. The current study examines the usefulness of a strategy for challenging or changing teachers' understandings of NOS. The teachers who participated in this study were 10 initial teacher education chemistry students and six experienced teachers from secondary and primary schools who were introduced to an explicit and reflective activity, a dramatic reading about a historical scientific development. Concept maps were used before and after the activity to assess teachers' knowledge of NOS. The participants also took part in a focus group interview to establish whether they perceived the activity as useful in developing their own understanding of NOS. Initial analysis led us to ask another group, comprising seven initial teacher education chemistry students, to take part in a modified study. These participants not only completed the same tasks as the previous participants but also completed a written reflection commenting on whether the activity and focus group discussion enhanced their understanding of NOS. Both Lederman et al.'s (Journal of Research in Science Teaching, 39(6), 497-521, 2002) concepts of NOS and notions of "naive" and "informed" understandings of NOS and Hay's (Studies in Higher Education, 32(1), 39-57, 2007) notions of "surface" and "deep" learning were used as frameworks to examine the participants' specific understandings of NOS and the depth of their learning. The ways in which participants' understandings of NOS were broadened or changed by taking part in the dramatic reading are presented. The impact of the data-gathering tools on the participants' professional learning is also discussed.

  13. A Kalman-Filter Approach to Estimating the Natural Rate of Unemployment

    Directory of Open Access Journals (Sweden)

    Victor V. Claar

    2005-08-01

    Full Text Available The terms “NAIRU” and “natural rate of unemployment” are not interchangeable. Further, while there is a consensus that the NAIRU represents an empirical macroeconomic relationship, little agreement exists regarding what is meant by the “natural rate of unemployment.” This paper estimates the natural rate of unemployment, defined here as the unemployment rate corresponding to equilibrium in the labor market. Rather than employ a Phillips curve, the model utilizes a macroeconomic-principles-level decomposition of the unemployment rate into its cyclical and noncyclical components. We then evaluate the estimated natural rate series by examining its relationship to structural variables from the labor market

  14. The endogeneity of the natural rate of growth: An application to Turkey

    Directory of Open Access Journals (Sweden)

    Acikgoz Senay

    2010-01-01

    Full Text Available The purpose of this paper is to examine the sensitivity of the Turkish economy’s natural rate of growth to the actual rate of growth, covering the period 1980-2008. To determine the reason why the natural rate of growth is endogenous, the long-run and the causality relationships between real gross domestic product and each of the production factors (labour force and physical capital stock are investigated with the bounds test. The natural rate of growth for the Turkish economy is found to be at 4.97 percent and the actual rate of growth in boom periods is approximately 35.6 percent; indicating endogeneity. However, according to the causality test results, the endogeneity of the natural rate of growth may be attributed to the total factor productivity rather than the labour force and physical capital stock. This result is important and the debate on this subject may lead to further studies.

  15. Understanding molecular interactions between scavenger receptor A and its natural product inhibitors through molecular modeling studies.

    Science.gov (United States)

    Pagare, Piyusha P; Zaidi, Saheem A; Zhang, Xiaomei; Li, Xia; Yu, Xiaofei; Wang, Xiang-Yang; Zhang, Yan

    2017-10-01

    Scavenger receptor A (SRA), as an immune regulator, has been shown to play important roles in lipid metabolism, cardiovascular diseases, and pathogen recognition. Several natural product inhibitors of SRA have been studied for their potential application in modulating SRA functions. To understand the binding mode of these inhibitors on SRA, we conducted systematic molecular modeling studies in order to identify putative binding domain(s) that may be responsible for their recognition to the receptor as well as their inhibitory activity. Treatment of SRA with one of the natural product inhibitors, rhein, led to significant dissociation of SRA oligomers to its trimer and dimer forms, which further supported our hypothesis on their putative mechanism of action. Such information is believed to shed light on design of more potent inhibitors for the receptor in order to develop potential therapeutics through immune system modulation. Published by Elsevier Inc.

  16. Thinking about television science: How students understand the nature of science from different program genres

    Science.gov (United States)

    Dhingra, Koshi

    2003-02-01

    Student views on the nature of science are shaped by a variety of out-of-school forces and television-mediated science is a significant force. To attempt to achieve a science for all, we need to recognize and understand the diverse messages about science that students access and think about on a regular basis. In this work I examine how high school students think about science that is mediated by four different program genres on television: documentary, magazine-format programming, network news, and dramatic or fictional programming. The following categories of findings are discussed: the ethics and validity of science, final form science, science as portrayed by its practitioners, and school science and television science. Student perceptions of the nature of science depicted on the program sample used in this study ranged from seeing science as comprising tentative knowledge claims to seeing science as a fixed body of facts.

  17. Fundamental challenges in mechanistic enzymology: progress toward understanding the rate enhancements of enzymes.

    Science.gov (United States)

    Herschlag, Daniel; Natarajan, Aditya

    2013-03-26

    Enzymes are remarkable catalysts that lie at the heart of biology, accelerating chemical reactions to an astounding extent with extraordinary specificity. Enormous progress in understanding the chemical basis of enzymatic transformations and the basic mechanisms underlying rate enhancements over the past decades is apparent. Nevertheless, it has been difficult to achieve a quantitative understanding of how the underlying mechanisms account for the energetics of catalysis, because of the complexity of enzyme systems and the absence of underlying energetic additivity. We review case studies from our own work that illustrate the power of precisely defined and clearly articulated questions when dealing with such complex and multifaceted systems, and we also use this approach to evaluate our current ability to design enzymes. We close by highlighting a series of questions that help frame some of what remains to be understood, and we encourage the reader to define additional questions and directions that will deepen and broaden our understanding of enzymes and their catalysis.

  18. Hybridizing Cultural Understandings of the Natural World to Foster Critical Science Literacy

    Science.gov (United States)

    Tang, Kok Sing

    Adolescents are constantly exposed to multiple cultural views of the natural world in juxtaposition with the dominant view of science taught in school. This dissertation explores the interaction of these multiple views, and how they shape students' understanding of and attitudes toward science. Situated in a high school physics classroom, a curricular approach was designed and enacted to open a space in the classroom for the convergence of multiple discourses (or systems of cultural knowledge), and subsequently study how students navigate around them. Ethnographic and critical inquiry revealed that when two or more discourses about similar natural events or objects (e.g., toss of a colorguard flag, human body) were directly juxtaposed in the classroom space, conceptual, affective, and ideological conflicts were generated for certain students. This was particularly so for students whose embedded experiences and social affiliations within certain discourse communities (e.g., sport clubs, church) led to their preferred ways of looking at the natural world from one particular discourse, and consequently a negative stance toward alternative ways in other discourses. However, through appropriate pedagogical design and support, such juxtaposition also created opportunities for some students to hybridize different cultural understandings of the natural world as they navigated around multiple discourses. Informed by Bakhtin's notions of heteroglossia and voice appropriation, the characteristics of such hybridization were found to include: (a) being aware of heteroglossic differences in the use of language, (b) a dynamic shift in identification toward the dialogic other, (c) a juxtaposition of the other's voices in one's utterances, and (d) a momentary suppression of one's preferences, for strategic motives. Not only did hybridization provide a means for some students to construct conceptual knowledge across discourses, but it also helped them develop critical literacy in

  19. Testing primary-school children's understanding of the nature of science.

    Science.gov (United States)

    Koerber, Susanne; Osterhaus, Christopher; Sodian, Beate

    2015-03-01

    Understanding the nature of science (NOS) is a critical aspect of scientific reasoning, yet few studies have investigated its developmental beginnings and initial structure. One contributing reason is the lack of an adequate instrument. Two studies assessed NOS understanding among third graders using a multiple-select (MS) paper-and-pencil test. Study 1 investigated the validity of the MS test by presenting the items to 68 third graders (9-year-olds) and subsequently interviewing them on their underlying NOS conception of the items. All items were significantly related between formats, indicating that the test was valid. Study 2 applied the same instrument to a larger sample of 243 third graders, and their performance was compared to a multiple-choice (MC) version of the test. Although the MC format inflated the guessing probability, there was a significant relation between the two formats. In summary, the MS format was a valid method revealing third graders' NOS understanding, thereby representing an economical test instrument. A latent class analysis identified three groups of children with expertise in qualitatively different aspects of NOS, suggesting that there is not a single common starting point for the development of NOS understanding; instead, multiple developmental pathways may exist. © 2014 The British Psychological Society.

  20. Spatial Reasoning and Understanding the Particulate Nature of Matter: A Middle School Perspective

    Science.gov (United States)

    Cole, Merryn L.

    This dissertation employed a mixed-methods approach to examine the relationship between spatial reasoning ability and understanding of chemistry content for both middle school students and their science teachers. Spatial reasoning has been linked to success in learning STEM subjects (Wai, Lubinski, & Benbow, 2009). Previous studies have shown a correlation between understanding of chemistry content and spatial reasoning ability (e.g., Pribyl & Bodner, 1987; Wu & Shah, 2003: Stieff, 2013), raising the importance of developing the spatial reasoning ability of both teachers and students. Few studies examine middle school students' or in-service middle school teachers' understanding of chemistry concepts or its relation to spatial reasoning ability. The first paper in this dissertation addresses the quantitative relationship between mental rotation, a type of spatial reasoning ability, and understanding a fundamental concept in chemistry, the particulate nature of matter. The data showed a significant, positive correlation between scores on the Purdue Spatial Visualization Test of Rotations (PSVT; Bodner & Guay, 1997) and the Particulate Nature of Matter Assessment (ParNoMA; Yezierski, 2003) for middle school students prior to and after chemistry instruction. A significant difference in spatial ability among students choosing different answer choices on ParNoMA questions was also found. The second paper examined the ways in which students of different spatial abilities talked about matter and chemicals differently. Students with higher spatial ability tended to provide more of an explanation, though not necessarily in an articulate matter. In contrast, lower spatial ability students tended to use any keywords that seemed relevant, but provided little or no explanation. The third paper examined the relationship between mental reasoning and understanding chemistry for middle school science teachers. Similar to their students, a significant, positive correlation between

  1. On the monetary nature of the interest rate in Keynes’s thought

    OpenAIRE

    Giancarlo Bertocco

    2011-01-01

    Keynes in the General Theory, explains the monetary nature of the interest rate by means of the liquidity preference theory. The objective of this paper is twofold. Fist, to point out the limits of an explanation of the monetary nature of the interest rate and thus of the non-neutrality of money based on the liquidity preference theory. Second, to present a different explanation of the monetary nature of the interest rate based on the arguments with which Keynes, following the General Theory,...

  2. Understanding Biological Rates and their Temperature Dependence, from Enzymes to Ecosystems

    Science.gov (United States)

    Prentice, E.; Arcus, V. L.

    2017-12-01

    Temperature responses over various scales in biological systems follow a similar pattern; negative curvature results in an optimum temperature (Topt) for activity/growth/turnover, with decreases in rates on either side of Topt. Previously this downturn in rates at high temperatures has been attributed to enzyme denaturation, where a failing of the basic driving units of metabolism was used to describe curvature at the enzyme and organism level. However, recent developments in our understanding of the factors governing enzyme rates at different temperatures have guided a new understanding of the responses of biological systems. Enzymes catalyse reactions by driving the substrate through a high energy species, which is tightly bound to the enzyme. Macromolecular rate theory (MMRT) has recently been developed to account for the changes in the system brought about by this tight binding, specifically the change in the physical parameter heat capacity (ΔCǂp), and the effect this has on the temperature dependence of enzyme reactions. A negative ΔCǂp imparts the signature negative curvature to rates in the absence of denaturation, and finds that Topt, ΔCǂp and curvature are all correlated, placing constraints on biological systems. The simplest of cells comprise thousands of enzymatically catalysed reactions, functioning in series and in parallel in metabolic pathways to determine the overall growth rate of an organism. Intuitively, the temperature effects of enzymes play a role in determining the overall temperature dependence of an organism, in tandem with cellular level regulatory responses. However, the effect of individual Topt values and curvature on overall pathway behaviour is less apparent. Here, this is investigated in the context of MMRT through the in vitro characterisation of a six-step metabolic pathway to understand the steps in isolation and functioning in series. Pathway behaviour is found to be approximately an average of the properties of the

  3. Combining natural and man-made DNA tracers to advance understanding of hydrologic flow pathway evolution

    Science.gov (United States)

    Dahlke, H. E.; Walter, M. T.; Lyon, S. W.; Rosqvist, G. N.

    2014-12-01

    Identifying and characterizing the sources, pathways and residence times of water and associated constituents is critical to developing improved understanding of watershed-stream connections and hydrological/ecological/biogeochemical models. To date the most robust information is obtained from integrated studies that combine natural tracers (e.g. isotopes, geochemical tracers) with controlled chemical tracer (e.g., bromide, dyes) or colloidal tracer (e.g., carboxilated microspheres, tagged clay particles, microorganisms) applications. In the presented study we explore how understanding of sources and flow pathways of water derived from natural tracer studies can be improved and expanded in space and time by simultaneously introducing man-made, synthetic DNA-based microtracers. The microtracer used were composed of polylactic acid (PLA) microspheres into which short strands of synthetic DNA and paramagnetic iron oxide nanoparticles are incorporated. Tracer experiments using both natural tracers and the DNA-based microtracers were conducted in the sub-arctic, glacierized Tarfala (21.7 km2) catchment in northern Sweden. Isotopic hydrograph separations revealed that even though storm runoff was dominated by pre-event water the event water (i.e. rainfall) contributions to streamflow increased throughout the summer season as glacial snow cover decreased. This suggests that glaciers are a major source of the rainwater fraction in streamflow. Simultaneous injections of ten unique DNA-based microtracers confirmed this hypothesis and revealed that the transit time of water traveling from the glacier surface to the stream decreased fourfold over the summer season leading to instantaneous rainwater contributions during storm events. These results highlight that integrating simultaneous tracer injections (injecting tracers at multiple places at one time) with traditional tracer methods (sampling multiple times at one place) rather than using either approach in isolation can

  4. Understanding the influence of power and empathic perspective-taking on collaborative natural resource management.

    Science.gov (United States)

    Wald, Dara M; Segal, Elizabeth A; Johnston, Erik W; Vinze, Ajay

    2017-09-01

    Public engagement in collaborative natural resource management necessitates shared understanding and collaboration. Empathic perspective-taking is a critical facilitator of shared understanding and positive social interactions, such as collaboration. Yet there is currently little understanding about how to reliably generate empathic perspective-taking and collaboration, particularly in situations involving the unequal distribution of environmental resources or power. Here we examine how experiencing the loss or gain of social power influenced empathic perspective-taking and behavior within a computer-mediated scenario. Participants (n = 180) were randomly assigned to each condition: high resources, low resources, lose resources, gain resources. Contrary to our expectations, participants in the perspective-taking condition, specifically those who lost resources, also lost perspective taking and exhibited egoistic behavior. This finding suggests that resource control within the collaborative process is a key contextual variable that influences perspective-taking and collaborative behavior. Moreover, the observed relationship between perspective-taking and egoistic behavior within a collaborative resource sharing exercise suggests that when resource control or access is unequal, interventions to promote perspective-taking deserve careful consideration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The Kalman Filter Approach for Estimating the Natural Unemployment Rate in Romania

    Directory of Open Access Journals (Sweden)

    Mihaela Simionescu

    2014-02-01

    Full Text Available The aim of this research is to determine the monthly natural rate of unemployment during the third quarter of 2013 in Romania. The Phillips curve approach is not valid for the Romanian economy, but Kalman filter is a suitable approach for computing the natural rate of unemployment. We make the assumption that the cyclical component follows a random walk. Predictions were made for the unemployment rate in Romania using Kalman approach during July-September 2013 and on this horizon an insignificant decrease was observed from a month to another. A value of 5.85% is expected for unemployment rate in Romania in September 2013.

  6. Comparative influence of dose rate and radiation nature, on lethality after big mammals irradiation

    International Nuclear Information System (INIS)

    Destombe, C.; Le Fleche, Ph.; Grasseau, A.; Reynal, A.

    1997-01-01

    For the same dose and the 30 days lethality as biological criterion, the dose rate influence is more important than the radiation nature on the results of an big mammals total body irradiation. (authors)

  7. Understanding the biological activity of high rate algae ponds through the calculation of oxygen balances.

    Science.gov (United States)

    Arbib, Zouhayr; de Godos Crespo, Ignacio; Corona, Enrique Lara; Rogalla, Frank

    2017-06-01

    Microalgae culture in high rate algae ponds (HRAP) is an environmentally friendly technology for wastewater treatment. However, for the implementation of these systems, a better understanding of the oxygenation potential and the influence of climate conditions is required. In this work, the rates of oxygen production, consumption, and exchange with the atmosphere were calculated under varying conditions of solar irradiance and dilution rate during six months of operation in a real scale unit. This analysis allowed determining the biological response of these dynamic systems. The rates of oxygen consumption measured were considerably higher than the values calculated based on the organic loading rate. The response to light intensity in terms of oxygen production in the bioreactor was described with one of the models proposed for microalgae culture in dense concentrations. This model is based on the availability of light inside the culture and the specific response of microalgae to this parameter. The specific response to solar radiation intensity showed a reasonable stability in spite of the fluctuations due to meteorological conditions. The methodology developed is a useful tool for optimization and prediction of the performance of these systems.

  8. Perception and Understanding of Invasive Alien Species Issues by Nature Conservation and Horticulture Professionals in Belgium

    Science.gov (United States)

    Vanderhoeven, Sonia; Piqueray, Julien; Halford, Mathieu; Nulens, Greet; Vincke, Jan; Mahy, Grégory

    2011-03-01

    We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based.

  9. Perception and understanding of invasive alien species issues by nature conservation and horticulture professionals in Belgium.

    Science.gov (United States)

    Vanderhoeven, Sonia; Piqueray, Julien; Halford, Mathieu; Nulens, Greet; Vincke, Jan; Mahy, Grégory

    2011-03-01

    We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based.

  10. Measurement and Modelling of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Heiselberg, Per; Kalyanova, Olena; Jensen, Rasmus Lund

    2008-01-01

    Air flow rate in a naturally ventilated double skin façade (DSF) is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes the results of two different methods to measure the air flow in a full-scale ...

  11. Measurement of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Jensen, Rasmus Lund; Heiselberg, Per

    2007-01-01

    Air flow rate in a naturally ventilated space is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes three different methods to measure the air flow in a full-scale outdoor test facility with a nat...

  12. "Very Good" Ratings in a Survey of Maternity Care: Kindness and Understanding Matter to Australian Women.

    Science.gov (United States)

    Todd, Angela L; Ampt, Amanda J; Roberts, Christine L

    2017-03-01

    Surveys have shown that women are highly satisfied with their maternity care. Their satisfaction has been associated with various demographic, personal, and care factors. Isolating the factors that most matter to women about their care can guide quality improvement efforts. This study aimed to identify the most significant factors associated with high ratings of care by women in the three maternity periods (antenatal, birth, and postnatal). A survey was sent to 2,048 women who gave birth at seven public hospitals in New South Wales, Australia, exploring their expectations of, and experiences with maternity care. Women's overall ratings of care for the antenatal, birth, and postnatal periods were analyzed, and a number of maternal characteristics and care factors examined as potential predictors of "Very good" ratings of care. Among 886 women with a completed survey, 65 percent assigned a "Very good" rating for antenatal care, 74 percent for birth care, 58 percent for postnatal care, and 44 percent for all three periods. One factor was strongly associated with care ratings in all three maternity periods: women who were "always or almost always" treated with kindness and understanding were 1.8-2.8 times more likely to rate their antenatal, birth, and postnatal care as "Very good." A limited number of other factors were significantly associated with high care ratings for one or two of the maternity periods. Women's perceptions about the quality of their interpersonal interactions with health caregivers have a significant bearing on women's views about their maternity care journey. © 2016 Wiley Periodicals, Inc.

  13. Book review: Serendipity: An ecologist’s quest to understand nature

    Science.gov (United States)

    Ball, E. E.; Adams, D. M.; Dupuie, J. N.; Jones, M. M.; McGovern, P. G.; Ruden, R. M.; Schmidt, S.R.; Vaziri, G. J.; Eeling, J. S.; Kirk, B. D.; McCombs, A. L.; Rabinowitz, A. B.; Thompson, K. M.; Hudson, Z. J.; Klaver, Robert W.

    2017-01-01

    A common thought among graduate students is: “how do established scientists get where they are today?” In Serendipity: An Ecologist’s Quest to Understand Nature, James Estes offers a personal reflection on research experiences spanning his 50-year career, beginning as a Ph.D. student in 1970 and concluding with recognition as a member of the National Academy of Sciences in 2014. Estes chronologically outlines the foundational trophic cascade ecology research that he and colleagues conducted in the Aleutian Islands, examining key relationships among kelp forests, sea otters, sea urchins, and killer whales through anecdotal stories of achievement and challenge. Estes’ 3 main goals in writing this book are to: (1) recount what he had learned from 50 years of research;...

  14. Understanding the systemic nature of cities to improve health and climate change mitigation.

    Science.gov (United States)

    Chapman, Ralph; Howden-Chapman, Philippa; Capon, Anthony

    2016-09-01

    Understanding cities comprehensively as systems is a costly challenge and is typically not feasible for policy makers. Nevertheless, focusing on some key systemic characteristics of cities can give useful insights for policy to advance health and well-being outcomes. Moreover, if we take a coevolutionary systems view of cities, some conventional assumptions about the nature of urban development (e.g. the growth in private vehicle use with income) may not stand up. We illustrate this by examining the coevolution of urban transport and land use systems, and institutional change, giving examples of policy implications. At a high level, our concern derives from the need to better understand the dynamics of urban change, and its implications for health and well-being. At a practical level, we see opportunities to use stylised findings about urban systems to underpin policy experiments. While it is now not uncommon to view cities as systems, policy makers appear to have made little use so far of a systems approach to inform choice of policies with consequences for health and well-being. System insights can be applied to intelligently anticipate change - for example, as cities are subjected to increasing natural system reactions to climate change, they must find ways to mitigate and adapt to it. Secondly, systems insights around policy cobenefits are vital for better informing horizontal policy integration. Lastly, an implication of system complexity is that rather than seeking detailed, 'full' knowledge about urban issues and policies, cities would be well advised to engage in policy experimentation to address increasingly urgent health and climate change issues. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Testing the hypothesis of the natural suicide rates: Further evidence from OECD data

    DEFF Research Database (Denmark)

    Andres, Antonio Rodriguez; Halicioglu, Ferda

    2011-01-01

    This paper provides further evidence on the hypothesis of the natural rate of suicide using the time series data for 15 OECD countries over the period 1970–2004. This hypothesis suggests that the suicide rate of a society could never be zero even if both the economic and the social conditions wer...

  16. Knowledge to Action - Understanding Natural Hazards-Induced Power Outage Scenarios for Actionable Disaster Responses

    Science.gov (United States)

    Kar, B.; Robinson, C.; Koch, D. B.; Omitaomu, O.

    2017-12-01

    The Sendai Framework for Disaster Risk Reduction 2015-2030 identified the following four priorities to prevent and reduce disaster risks: i) understanding disaster risk; ii) strengthening governance to manage disaster risk; iii) investing in disaster risk reduction for resilience and; iv) enhancing disaster preparedness for effective response, and to "Build Back Better" in recovery, rehabilitation and reconstruction. While forecasting and decision making tools are in place to predict and understand future impacts of natural hazards, the knowledge to action approach that currently exists fails to provide updated information needed by decision makers to undertake response and recovery efforts following a hazard event. For instance, during a tropical storm event advisories are released every two to three hours, but manual analysis of geospatial data to determine potential impacts of the event tends to be time-consuming and a post-event process. Researchers at Oak Ridge National Laboratory have developed a Spatial Decision Support System that enables real-time analysis of storm impact based on updated advisory. A prototype of the tool that focuses on determining projected power outage areas and projected duration of outages demonstrates the feasibility of integrating science with decision making for emergency management personnel to act in real time to protect communities and reduce risk.

  17. Understanding the nature of apraxia of speech: Theory, analysis, and treatment

    Directory of Open Access Journals (Sweden)

    Kirrie J. Ballard

    2010-08-01

    Full Text Available Researchers have interpreted the behaviours of individuals with acquired apraxia of speech (AOS as impairment of linguistic phonological processing, motor control, or both. Acoustic, kinematic, and perceptual studies of speech in more recent years have led to significant advances in our understanding of the disorder and wide acceptance that it affects phonetic - motoric planning of speech. However, newly developed methods for studying nonspeech motor control are providing new insights, indicating that the motor control impairment of AOS extends beyond speech and is manifest in nonspeech movements of the oral structures. We present the most recent developments in theory and methods to examine and define the nature of AOS. Theories of the disorder are then related to existing treatment approaches and the efficacy of these approaches is examined. Directions for development of new treatments are posited. It is proposed that treatment programmes driven by a principled account of how the motor system learns to produce skilled actions will provide the most efficient and effective framework for treating motorbased speech disorders. In turn, well controlled and theoretically motivated studies of treatment efficacy promise to stimulate further development of theoretical accounts and contribute to our understanding of AOS.

  18. The Relationship between Biology Teachers' Understanding of the Nature of Science and the Understanding and Acceptance of the Theory of Evolution

    Science.gov (United States)

    Cofré, Hernán; Cuevas, Emilia; Becerra, Beatriz

    2017-01-01

    Despite the importance of the theory of evolution (TE) to scientific knowledge, a number of misconceptions continue to be found among biology teachers. In this context, the first objective of this study was to identify the impact of professional development programme (PDP) on teachers' understanding of nature of science (NOS) and evolution and on…

  19. Establishing the natural history and growth rate of ameloblastoma with implications for management: systematic review and meta-analysis.

    Science.gov (United States)

    Chae, Michael P; Smoll, Nicolas R; Hunter-Smith, David J; Rozen, Warren Matthew

    2015-01-01

    Ameloblastoma is the second most common odontogenic tumor, known to be slow-growing, persistent, and locally aggressive. Recent data suggests that ameloblastoma is best treated with wide resection and adequate margins. Following primary excision, bony reconstruction is often necessary for a functional and aesthetically satisfactory outcome, making early diagnosis paramount. Despite earlier diagnosis potentially limiting the extent of resection and reconstruction, an understanding of the growth rate and natural history of ameloblastoma has been notably lacking from the literature. A systematic review of the literature was conducted by reviewing relevant articles from PubMed and Web of Science databases. Each article's level of evidence was formally appraised according to the Centre of Evidence Based Medicine (CEBM), with data from each utilized in a meta-analysis of growth rates for ameloblastoma. Literature regarding the natural history of ameloblastoma is limited since the tumor is immediately acted upon at its initial detection, unless the patient voluntarily refuses a surgical intervention. From the limited data, it is derived that the highest estimated growth rate is associated with solid, multicystic type and the lowest rate with peripheral ameloblastomas. After meta-analysis, the calculated mean specific grow rate is 87.84% per year. The growth rate of ameloblastoma has been demonstrated, offering prognostic and management information, particularly in cases where a delay in management is envisaged.

  20. Animal density and track counts: understanding the nature of observations based on animal movements.

    Directory of Open Access Journals (Sweden)

    Derek Keeping

    Full Text Available Counting animals to estimate their population sizes is often essential for their management and conservation. Since practitioners frequently rely on indirect observations of animals, it is important to better understand the relationship between such indirect indices and animal abundance. The Formozov-Malyshev-Pereleshin (FMP formula provides a theoretical foundation for understanding the relationship between animal track counts and the true density of species. Although this analytical method potentially has universal applicability wherever animals are readily detectable by their tracks, it has long been unique to Russia and remains widely underappreciated. In this paper, we provide a test of the FMP formula by isolating the influence of animal travel path tortuosity (i.e., convolutedness on track counts. We employed simulations using virtual and empirical data, in addition to a field test comparing FMP estimates with independent estimates from line transect distance sampling. We verify that track counts (total intersections between animals and transects are determined entirely by density and daily movement distances. Hence, the FMP estimator is theoretically robust against potential biases from specific shapes or patterns of animal movement paths if transects are randomly situated with respect to those movements (i.e., the transects do not influence animals' movements. However, detectability (the detection probability of individual animals is not determined simply by daily travel distance but also by tortuosity, so ensuring that all intersections with transects are counted regardless of the number of individual animals that made them becomes critical for an accurate density estimate. Additionally, although tortuosity has no bearing on mean track encounter rates, it does affect encounter rate variance and therefore estimate precision. We discuss how these fundamental principles made explicit by the FMP formula have widespread implications for

  1. Measuring Infiltration Rates in Homes as a Basis for Understanding Indoor Air Quality

    Science.gov (United States)

    Jerz, G. G.; Lamb, B. K.; Pressley, S. N.; O'Keeffe, P.; Fuchs, M.; Kirk, M.

    2015-12-01

    Infiltration rates, or the rate of air exchange, of houses are important to understand because ventilation can be a dominate factor in determining indoor air quality. There are chemicals that are emitted from surfaces or point sources inside the home which are harmful to humans; these chemicals come from various objects including furniture, cleaning supplies, building materials, gas stoves, and the surrounding environment. The use of proper ventilation to cycle cleaner outdoor air into the house can be crucial for maintaining healthy living conditions in the home. At the same time, there can also be outdoor pollutants which infiltrate the house and contribute to poor indoor air quality. In either case, it is important to determine infiltration rates as a function of outdoor weather conditions, the house structure properties and indoor heating and cooling systems. In this work, the objective is to measure ventilation rates using periodic releases of a tracer gas and measuring how quickly the tracer concentration decays. CO2 will be used as the tracer gas because it is inert and harmless at low levels. An Arduino timer is connected to a release valve which controls the release of 9.00 SLPM of CO2 into the uptake vent within the test home. CO2 will be released until there is at least a 200 to 300 ppm increase above ambient indoor levels. Computers with CO2 sensors and temperature/pressure sensors attached will be used to record data from different locations within the home which will continuously record data up to a week. The results from these periodic ventilation measurements will be analyzed with respect to outdoor wind and temperature conditions and house structure properties. The data will be used to evaluate an established indoor air quality model.

  2. Understanding stakeholder preferences for flood adaptation alternatives with natural capital implications

    Directory of Open Access Journals (Sweden)

    Jonathon R. Loos

    2016-09-01

    Full Text Available Inland flood risks are defined by a range of environmental and social factors, including land use and floodplain management. Shifting patterns of storm intensity and precipitation, attributed to climate change, are exacerbating flood risk in regions across North America. Strategies for adapting to growing flood risks and climate change must account for a community's specific vulnerabilities, and its local economic, environmental, and social conditions. Through a stakeholder-engaged methodology, we designed an interactive decision exercise to enable stakeholders to evaluate alternatives for addressing specific community flood vulnerabilities. We used a multicriteria framework to understand what drives stakeholder preferences for flood mitigation and adaptation alternatives, including ecosystem-based projects. Results indicated strong preferences for some ecosystem-based projects that utilize natural capital, generated a useful discussion on the role of individual values in driving decisions and a critique of local environmental and hazard planning procedure, and uncovered support for a river management alternative that had previously been considered socially infeasible. We conclude that a multicriteria decision framework may help ensure that the multiple benefit qualities of natural capital projects are considered by decision makers. Application of a utility function can demonstrate the role of individual decision-maker values in decision outcomes and help illustrate why one alternative may be a better choice than another. Although designing an efficient and accurate multicriteria exercise is quite challenging and often data intensive, we imagine that this method is applicable elsewhere. It may be especially suitable to group decisions that involve varying levels of expertise and competing values, as is often the case in planning for the ecological and human impacts of climate change.

  3. Community Resilience: Increasing Public Understanding of Risk and Vulnerability to Natural Hazards through Informal Education

    Science.gov (United States)

    Salna, E.

    2017-12-01

    The Extreme Events Institute's (EEI) International Hurricane Research Center (IHRC) at Florida International University (FIU) in Miami, Florida, as a NOAA Weather-Ready Nation Ambassador, is dedicated to make South Florida, Ready, Responsive and Resilient. IHRC with funding from the Florida Division of Emergency Management (FDEM) has developed several museum exhibits and events. This includes the hands-on FIU Wall of Wind exhibit for the National Building Museum in Washington, DC, the Frost Science Museum in Miami, Florida, and the Museum of Discovery and Science (MODS) in Fort Lauderdale, Florida. The exhibit teaches the public about hurricane wind engineering research, enhanced building codes, and the importance of protecting your home's windows and doors with code-approved shutters. In addition, IHRC and MODS facilitate Eye of the Storm, a free-of-charge, community event with interactive hurricane science, and preparedness activities, including the entertaining Owlie Skywarn live theater show and live air cannon missile impact demonstrations. This annual event includes many local, state and federal partners, including NOAA and NWS. The IHRC also developed the FIU Wall of Wind Mitigation Challenge. As the next generation of engineers to address natural hazards and extreme weather, this STEM education event features a competition between high school teams to develop innovative wind mitigation concepts and real-life human safety and property protection solutions. IHRC and MODS are also developing a new exhibit of a Hazard/Risk Equation that will "come to life," through virtual reality (VR) technology in a state-of-the art 7D theater. The exhibit will provide a better public understanding of how changes in exposures and vulnerabilities will determine whether a community experiences an emergency, disaster or catastrophe. It will raise public consciousness and drive home the point that communities need not passively accept natural hazard risks. Ultimately, if we raise

  4. Natural formation and degradation of chloroacetic acids and volatile organochlorines in forest soil--challenges to understanding.

    Science.gov (United States)

    Laturnus, Frank; Fahimi, Isabelle; Gryndler, Milan; Hartmann, Anton; Heal, Mathew R; Matucha, Miroslav; Schöler, Heinz Friedrich; Schroll, Reiner; Svensson, Teresia

    2005-07-01

    The anthropogenic environmental emissions of chloroacetic acids and volatile organochlorines have been under scrutiny in recent years because the two compound groups are suspected to contribute to forest dieback and stratospheric ozone destruction, respectively. The two organochlorine groups are linked because the atmospheric photochemical oxidation of some volatile organochlorine compounds is one source of phytotoxic chloroacetic acids in the environment. Moreover, both groups are produced in higher amounts by natural chlorination of organic matter, e.g. by soil microorganisms, marine macroalgae and salt lake bacteria, and show similar metabolism pathways. Elucidating the origin and fate of these organohalogens is necessary to implement actions to counteract environmental problems caused by these compounds. While the anthropogenic sources of chloroacetic acids and volatile organochlorines are relatively well-known and within human control, knowledge of relevant natural processes is scarce and fragmented. This article reviews current knowledge on natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soils, with particular emphasis on processes in the rhizosphere, and discusses future studies necessary to understand the role of forest soils in the formation and degradation of these compounds. Reviewing the present knowledge of the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil has revealed gaps in knowledge regarding the actual mechanisms behind these processes. In particular, there remains insufficient quantification of reliable budgets and rates of formation and degradation of chloroacetic acids and volatile organochlorines in forest soil (both biotic and abiotic processes) to evaluate the strength of forest ecosystems regarding the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale

  5. Numerical Modeling of Variable Fluid Injection-Rate Modes on Fracturing Network Evolution in Naturally Fractured Formations

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2016-05-01

    Full Text Available In this study, variable injection-rate technology was numerically investigated in a pre-existing discrete fracture network (DFN formation, the Tarim Basin in China. A flow-stress-damage (FSD coupling model has been used in an initial attempt towards how reservoir response to variable injection-rates at different hydraulic fracturing stages. The established numerical model simultaneously considered the macroscopic and microscopic heterogeneity characteristics. Eight numerical cases were studied. Four cases were used to study the variable injection-rate technology, and the other four cases were applied for a constant injection-rate in order to compare with the variable injection-rate technology. The simulation results show that the variable injection-rate technology is a potentially good method to a form complex fracturing networks. The hydraulic fracturing effectiveness when increasing the injection-rate at each stage is the best, also, the total injected fluid is at a minimum. At the initial stage, many under-fracturing points appear around the wellbore with a relatively low injection-rate; the sudden increase of injection rate drives the dynamic propagation of hydraulic fractures along many branching fracturing points. However, the case with decreasing injection rate is the worst. By comparing with constant injection-rate cases, the hydraulic fracturing effectiveness with variable flow rate technology is generally better than those with constant injection-rate technology. This work strongly links the production technology and hydraulic fracturing effectiveness evaluation and aids in the understanding and optimization of hydraulic fracturing simulations in naturally fractured reservoirs.

  6. Understanding the bonding nature of uranyl ion and functionalized graphene: a theoretical study.

    Science.gov (United States)

    Wu, Qun-Yan; Lan, Jian-Hui; Wang, Cong-Zhi; Xiao, Cheng-Liang; Zhao, Yu-Liang; Wei, Yue-Zhou; Chai, Zhi-Fang; Shi, Wei-Qun

    2014-03-20

    Studying the bonding nature of uranyl ion and graphene oxide (GO) is very important for understanding the mechanism of the removal of uranium from radioactive wastewater with GO-based materials. We have optimized 22 complexes between uranyl ion and GO applying density functional theory (DFT) combined with quasi-relativistic small-core pseudopotentials. The studied oxygen-containing functional groups include hydroxyl, carboxyl, amido, and dimethylformamide. It is observed that the distances between uranium atoms and oxygen atoms of GO (U-OG) are shorter in the anionic GO complexes (uranyl/GO(-/2-)) compared to the neutral GO ones (uranyl/GO). The formation of hydrogen bonds in the uranyl/GO(-/2-) complexes can enhance the binding ability of anionic GO toward uranyl ions. Furthermore, the thermodynamic calculations show that the changes of the Gibbs free energies in solution are relatively more negative for complexation reactions concerning the hydroxyl and carboxyl functionalized anionic GO complexes. Therefore, both the geometries and thermodynamic energies indicate that the binding abilities of uranyl ions toward GO modified by hydroxyl and carboxyl groups are much stronger compared to those by amido and dimethylformamide groups. This study can provide insights for designing new nanomaterials that can efficiently remove radionuclides from radioactive wastewater.

  7. From the Horse's Mouth: Why scientists' views are crucial to nature of science understanding

    Science.gov (United States)

    Hodson, Derek; Wong, Siu Ling

    2014-11-01

    Written in response to criticism of our work by Fouad Abd-El-Khalick, this position paper reaffirms and reinforces our position about the need to broaden and enrich the scope of nature of science (NOS) oriented curricula by exposing students to the voices of practising scientists. While Abd-El-Khalick's motivation for promoting the so-called consensus view of NOS is rooted in issues of assessment (or 'benchmarking', as he calls it), we argue that the major reason for teaching about NOS is its contribution to what Shen calls civic and cultural scientific literacy. We are critical of the consensus view for its philosophical naivety, failure to reflect contemporary scientific practice and potential for confusing students, and we re-state our view that it is important to expose students to a diversity of practice among the sub-disciplines of science. We argue that richer NOS understanding and a more authentic view of scientific practice can be achieved through direct and indirect contact with scientists at the cutting edge of research and development, which we characterise as learning about scientists, learning from scientists and learning with scientists.

  8. Towards understanding the nature of conflict of interest and its application to the discipline of nursing.

    Science.gov (United States)

    Crigger, Nancy J

    2009-10-01

    Most incidences of dishonesty in research, financial investments that promote personal financial gain, and kickback scandals begin as conflicts of interest (COI). Research indicates that healthcare professionals who maintain COI relationships make less optimal and more expensive patient care choices. The discovery of COI relationships also negatively impact patient and public trust. Many disciplines are addressing this professional issue, but little work has been done towards understanding and applying this moral category within a nursing context. Do COIs occur in nursing and are they problematic? What are the morally appropriate responses to COI for our discipline and for individual practicing nurses? In this paper I examine the nature of 'conflict of interest' as a general ethical category, its characteristics and its application to our discipline. Conflict of interest is an odd moral category that may actually or potentially result in immoral decisions. The moral justification for COI is grounded prime facie by the moral value of respect for persons and principle of fidelity from which trust is developed and maintained. In review of the historical development, there appears to be consensus on some qualities of COI that are presented. I conclude that making judgements about COI are challenging and often difficult to determine from a nursing perspective. Improving nurses' and professional organizations' awareness of COI and sharpening our ability to respond appropriately when COI arise can reduce potential harm and promote trust in those whom we serve.

  9. Computational Intelligence-Assisted Understanding of Nature-Inspired Superhydrophobic Behavior.

    Science.gov (United States)

    Zhang, Xia; Ding, Bei; Cheng, Ran; Dixon, Sebastian C; Lu, Yao

    2018-01-01

    In recent years, state-of-the-art computational modeling of physical and chemical systems has shown itself to be an invaluable resource in the prediction of the properties and behavior of functional materials. However, construction of a useful computational model for novel systems in both academic and industrial contexts often requires a great depth of physicochemical theory and/or a wealth of empirical data, and a shortage in the availability of either frustrates the modeling process. In this work, computational intelligence is instead used, including artificial neural networks and evolutionary computation, to enhance our understanding of nature-inspired superhydrophobic behavior. The relationships between experimental parameters (water droplet volume, weight percentage of nanoparticles used in the synthesis of the polymer composite, and distance separating the superhydrophobic surface and the pendant water droplet in adhesive force measurements) and multiple objectives (water droplet contact angle, sliding angle, and adhesive force) are built and weighted. The obtained optimal parameters are consistent with the experimental observations. This new approach to materials modeling has great potential to be applied more generally to aid design, fabrication, and optimization for myriad functional materials.

  10. The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

    Science.gov (United States)

    Hunter, Chad M; Huang, Wen; Mackay, Trudy F C; Singh, Nadia D

    2016-04-01

    Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

  11. The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Chad M Hunter

    2016-04-01

    Full Text Available Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

  12. Energy policy act transportation study: Interim report on natural gas flows and rates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-17

    This report, Energy Policy Act Transportation Study: Interim Report on Natural Gas Flows and Rates, is the second in a series mandated by Title XIII, Section 1340, ``Establishment of Data Base and Study of Transportation Rates,`` of the Energy Policy Act of 1992 (P.L. 102--486). The first report Energy Policy Act Transportation Study: Availability of Data and Studies, was submitted to Congress in October 1993; it summarized data and studies that could be used to address the impact of legislative and regulatory actions on natural gas transportation rates and flow patterns. The current report presents an interim analysis of natural gas transportation rates and distribution patterns for the period from 1988 through 1994. A third and final report addressing the transportation rates and flows through 1997 is due to Congress in October 2000. This analysis relies on currently available data; no new data collection effort was undertaken. The need for the collection of additional data on transportation rates will be further addressed after this report, in consultation with the Congress, industry representatives, and in other public forums.

  13. Germline mutation rates in families residing in high level natural radiation areas of Kerala coast in southwest India

    International Nuclear Information System (INIS)

    Das, Birajalaxmi; Ghosh, Anu; Ahmad, Shazia; Saini, DivyaIakshmi; Chauhan, P.S.; Seshadri, M.

    2010-01-01

    For this study, 200 nuclear families have been analyzed using over 40 mini- and microsatellite markers. Cord blood samples for the child and peripheral blood samples for the parent(s) were collected in EDTA vacuutainers from the hospital units located in High Level Natural Radiation Areas (HLNRA) and Normal Level Natural Radiation Areas (NLNRA). Both the parents of the newborn were exposed to the background dose. The families were grouped into four distinct dose groups - NLNRA group 5.00 mGy/year. An overall mutation rate of 2.08 X 10 -3 per cell per generation was observed for NLNRA and 2.12 X 10 -3 per cell per generation for HLNRA families. No radiation induced dose response was observed for the stratified groups. Thus, this study shows that mutation rates at mini- and microsatellites in the off springs of the parents living in the high background radiation areas of Kerala does not vary with radiation exposure. This is the first report to understand germline mutation rates at hypervariable loci in families residing in high level natural radiation areas of the world

  14. Understanding the life cycle surface land requirements of natural gas-fired electricity

    Science.gov (United States)

    Jordaan, Sarah M.; Heath, Garvin A.; Macknick, Jordan; Bush, Brian W.; Mohammadi, Ehsan; Ben-Horin, Dan; Urrea, Victoria; Marceau, Danielle

    2017-10-01

    The surface land use of fossil fuel acquisition and utilization has not been well characterized, inhibiting consistent comparisons of different electricity generation technologies. Here we present a method for robust estimation of the life cycle land use of electricity generated from natural gas through a case study that includes inventories of infrastructure, satellite imagery and well-level production. Approximately 500 sites in the Barnett Shale of Texas were sampled across five life cycle stages (production, gathering, processing, transmission and power generation). Total land use (0.62 m2 MWh-1, 95% confidence intervals ±0.01 m2 MWh-1) was dominated by midstream infrastructure, particularly pipelines (74%). Our results were sensitive to power plant heat rate (85-190% of the base case), facility lifetime (89-169%), number of wells per site (16-100%), well lifetime (92-154%) and pipeline right of way (58-142%). When replicated for other gas-producing regions and different fuels, our approach offers a route to enable empirically grounded comparisons of the land footprint of energy choices.

  15. Comparing artificial and natural selection in rate of adaptation to genetic stress in Aspergillus nidulans

    NARCIS (Netherlands)

    Schoustra, S.E.; Slakhorst-Wandel, S.M.; Debets, A.J.M.; Hoekstra, R.F.

    2005-01-01

    In an experimental study of adaptation to negative pleiotropic effects of a major fungicide resistance mutation in the filamentous fungus Aspergillus nidulans we have investigated the relative effectiveness of artificial selection vs. natural selection on the rate of compensatory evolution. Using

  16. Using the Activity Model of Inquiry to Enhance General Chemistry Students' Understanding of Nature of Science

    Science.gov (United States)

    Marchlewicz, Sara C.; Wink, Donald J.

    2011-01-01

    Nature of science refers to the processes of scientific activity and the social and cultural premises involved in the creation of scientific knowledge. Having an informed view of nature of science is important in the development of scientifically literate citizens. However, students often come to the classroom with misconceptions about nature of…

  17. Understanding coupling between natural and human systems to ensure disease resilient societies

    Science.gov (United States)

    Jutla, A.; Nguyen, T. H.; Colwell, R. R.; Akanda, A. S.

    2016-12-01

    Human well-being is one of the key long-term indicators of a sustainable environment. John Snow, a prominent 19th century physician, provided insights on the role of drinking contaminated water and cholera outbreak(s). Extrapolation of Snow's discovery on locating source of cholera bacteria (in local wells) lead to the tenets of traditional doctrines of environmental sustainability of water where source capacities (such as physical condition of water) are directly linked to sink capacities (e.g., bacterial growth in water) of a system, a balance that must be maintained to sustain human life supporting mechanisms. With a changing climate, stress on availability of safe drinking water is likely to increase, particularly where population vulnerability intersects with hydroclimatic extremes. This raises a critical question on how environmental sustainability of water will affect human societies. A dynamic equilibrium exists between large scale geophysical (e.g., sea surface temperature-SST; precipitation, evaporative fluxes) and local scale water-ecological processes (salinity, plankton, organic matter) in water resources (ponds, rivers, lakes). The ecological processes aid in growth and proliferation of water based pathogens (such as cholera, Rotavirus, Shigella and other vibrios). Societal determinants, such as access to safe drinking water and sanitation facilities, defines interaction of human population with water. The feedback loop, between geophysical and water-ecological processes is fundamental to ensure a sustainable environment for human well-being. However, the feedback loops are often misconstrued resulting in massive loss of human life, and further leading to outbreak of diseases at various spatial and temporal scales across region(s). Using historical data on Cholera and Zika virus as examples, we will demonstrate the intricacies involved in understanding coupled human-natural system. The two infections result from a very different asymmetric

  18. Understanding social reproduction: The recursive nature of structure and agency within a science class

    Science.gov (United States)

    Seiler, Gale A.

    Schools and science classrooms within schools continue to contribute to social reproduction and to the disenfranchisement of inner city African American students though attempts have been made to remedy the situation through standards, high-stakes testing, and compensatory programs. Such reforms ignore the sociocultural, political, and economic contexts of the individual students in the schools they are impacting. They do not take into account the uniqueness and diversity of the learners in these settings and have not included the voices of the students. Another possibility was studied here; that of starting with the cultural capital of the learner rather than with external standards. In a non-required science course at a local high school two coteachers endeavored to enact a student-emergent curriculum as a way to foster student agency and to counteract the reproductive nature of schools. The class was examined as a field within multiple other fields. The dialectical relationship between structure and agency in the class was used to frame the analysis and the tension between them was examined at several levels through video and audio analysis. Structural and rational choice views of action were abandoned in favor of an understanding hinged upon strategies of action that actors construct from cultural toolkits in and through practice. In this setting the students and teachers co-constructed a class that can be described and characterized in certain ways yet contained many counter-examples and alternative characterizations. A continuum of successes and failures, agency and subjectivity can be found in the trends and counter-trends in the course. The contradictions were examined to portray the complexity of the interactions and the possibilities for agency within them.

  19. Toward Understanding the Cold, Hot, and Neutral Nature of Chinese Medicines Using in Silico Mode-of-Action Analysis.

    Science.gov (United States)

    Fu, Xianjun; Mervin, Lewis H; Li, Xuebo; Yu, Huayun; Li, Jiaoyang; Mohamad Zobir, Siti Zuraidah; Zoufir, Azedine; Zhou, Yang; Song, Yongmei; Wang, Zhenguo; Bender, Andreas

    2017-03-27

    One important, however, poorly understood, concept of Traditional Chinese Medicine (TCM) is that of hot, cold, and neutral nature of its bioactive principles. To advance the field, in this study, we analyzed compound-nature pairs from TCM on a large scale (>23 000 structures) via chemical space visualizations to understand its physicochemical domain and in silico target prediction to understand differences related to their modes-of-action (MoA) against proteins. We found that overall TCM natures spread into different subclusters with specific molecular patterns, as opposed to forming coherent global groups. Compounds associated with cold nature had a lower clogP and contain more aliphatic rings than the other groups and were found to control detoxification, heat-clearing, heart development processes, and have sedative function, associated with "Mental and behavioural disorders" diseases. While compounds associated with hot nature were on average of lower molecular weight, have more aromatic ring systems than other groups, frequently seemed to control body temperature, have cardio-protection function, improve fertility and sexual function, and represent excitatory or activating effects, associated with "endocrine, nutritional and metabolic diseases" and "diseases of the circulatory system". Compounds associated with neutral nature had a higher polar surface area and contain more cyclohexene moieties than other groups and seem to be related to memory function, suggesting that their nature may be a useful guide for their utility in neural degenerative diseases. We were hence able to elucidate the difference between different nature classes in TCM on the molecular level, and on a large data set, for the first time, thereby helping a better understanding of TCM nature theory and bridging the gap between traditional medicine and our current understanding of the human body.

  20. The Importance of Ecology-Based Nature Education Project in Terms of Nature Integration and Understanding the Human-Ecosystem Relationship

    Science.gov (United States)

    Meydan, Ali

    2011-01-01

    The aim of this project is to define the importance of 12-day ecology-based education training upon integration with nature and understanding the human-ecosystem relationship. In accordance with this purpose, there has been collected some survey data interviewing with the participants of "Lake Beysehir National Park and Ecology-based Nature…

  1. Praon volucre (Hymenoptera: Braconidae: Aphidiinae), a natural enemy of Macrosiphum euphorbiae (Hemiptera: Aphididae): Life table and intrinsic rate of population increase

    NARCIS (Netherlands)

    Lins, J.C.; Bueno, V.H.P.; Silva, D.B.; Sampaio, M.V.; Lenteren, van J.C.

    2011-01-01

    Life table data of natural enemies are often used to understand their population dynamics and estimate their potential role in the biological control of pests. Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae) is an important pest of several crops and its intrinsic rate of population increase

  2. Spatial variation of natural terrestrial γ-ray dose rates in Brunei

    International Nuclear Information System (INIS)

    Hu, S.J.; Lai, K.K.

    1998-01-01

    A carborne survey of natural terrestrial y-ray dose rates along the main roads of the western part of Brunei Darussalam was carried out using two portable type 1.5'φx4' NaI(T1) and 1'φx2' NaI(T1) scintillation counters. A series of semicontinuous count rates measurements were performed inside a moving vehicle. This yielded equal-distance data which were analysed statistically to obtain the spatial variation of the natural terrestrial γ-ray dose rates. The equal-distance data of dose rates were obtained by correcting for shielding effect of the car. The thickness of the pavement and the contribution from the pavement material were estimated from a correlation curve between the dose rates measured on pavements and on the nearby soils. A spectral analysis of the equal-distance data enabled us to clarify the structure of the spatial variation in dose rates. The data could be reasonably smoothened by removing the random noise components in a higher wave number region

  3. Business Communication and the Natural Environment: Using Traditional and Contemporary Perspectives to Understand the Connections.

    Science.gov (United States)

    Bullis, Connie

    1997-01-01

    Argues that business communication scholarship has not attended to the natural environment. Notes that organizational scholarship has theorized business as it relates to the natural environment but has not thoroughly understood how communication functions in this relationship. Argues that business communication should adopt a Gaian perspective…

  4. Understanding the Trembles of Nature: How Do Disaster Experiences Shape Bank Risk Taking?

    NARCIS (Netherlands)

    Bos, Jaap; Li, Runliang

    2017-01-01

    This paper examines the impact of natural disaster experiences on banks’ business practices. Using earthquake and banking data for California, we find that banks that have had stronger earthquake experiences change their practices, both as a result of the natural disasters’ effects on local deposit

  5. Understanding Natural Sciences Education in a Reggio Emilia-Inspired Preschool

    Science.gov (United States)

    Inan, Hatice Zeynep; Trundle, Kathy Cabe; Kantor, Rebecca

    2010-01-01

    This ethnographic study explored aspects of how the natural sciences were represented in a Reggio Emilia-inspired laboratory preschool. The natural sciences as a discipline--a latecomer to preschool curricula--and the internationally known approach, Reggio Emilia, interested educators and researchers, but there was little research about science in…

  6. What Does "Natural Capital" Do? The Role of Metaphor in Economic Understanding of the Environment

    Science.gov (United States)

    Akerman, Maria

    2005-01-01

    At the time of its introduction at the end of the 1980s, the concept of natural capital represented new, more ecologically aware thinking in economics. As a symbol of novel thinking, the metaphor of natural capital stimulated a debate between different disciplinary traditions on the definitions of the concept and research priorities and methods.…

  7. Understanding the Heterogeneous Nature of Science: A Comprehensive Notion of PCK for Scientific Literacy

    Science.gov (United States)

    Van Dijk, Esther M.

    2014-01-01

    This paper is concerned with the conceptualization of pedagogical content knowledge (PCK) for teaching about the nature of science. In contrast to the view that science teachers need to develop a specific "PCK for nature of science," an alternative, more comprehensive notion of PCK for science teaching is suggested. The point of…

  8. Understanding the social acceptability of natural resource decisionmaking processes by using a knowledge base modeling approach.

    Science.gov (United States)

    Christina Kakoyannis; Bruce Shindler; George. Stankey

    2001-01-01

    Natural resource managers are being confronted with increasing conflict and litigation with those who find their management plans unacceptable. Compatible and sustainable management decisions necessitate that natural resource agencies generate plans that are not only biologically possible and economically feasible but also socially acceptable. Currently, however, we...

  9. Public Utility Regulatory Policies Act of 1978: Natural Gas Rate Design Study

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-05-01

    First, the comments on May 3, 1979 Notice of Inquiry of DOE relating to the Gas Utility Rate Design Study Required by Section 306 of PURPA are presented. Then, comments on the following are included: (1) ICF Gas Utility Model, Gas Utility Model Data Outputs, Scenario Design; (2) Interim Model Development Report with Example Case Illustrations; (3) Interim Report on Simulation of Seven Rate Forms; (4) Methodology for Assessing the Impacts of Alternative Rate Designs on Industrial Energy Use; (5) Simulation of Marginal-Cost-Based Natural Gas Rates; and (6) Preliminary Discussion Draft of the Gas Rate Design Study. Among the most frequent comments expressed were the following: (a) the public should be given the opportunity to review the final report prior to its submission to Congress; (b) results based on a single computer model of only four hypothetical utility situations cannot be used for policy-making purposes for individual companies or the entire gas industry; (c) there has been an unobjective treatment of traditional and economic cost rate structures; the practical difficulties and potential detrimental consequences of economic cost rates are not fully disclosed; and (d) it is erroneous to assume that end users, particularly residential customers, are influenced by price signals in the rate structure, as opposed to the total bill.

  10. An Empirical Analyses of Unemployment Hysteresis and Natural Rate of Unemployment Approaches for MENA Countries

    Directory of Open Access Journals (Sweden)

    Sinan ERDOĞAN

    2016-07-01

    Full Text Available This paper aims to test natural rate of unemployment and approach of unemployment hysteresis in MENA*** countries for the period of 1991-2014 by using panel data analysis methods which considering the cross-sectional dependency properties. Cross-sectional dependency test results indicate that there is cross-section dependency among all variables. According to CADF test results, unemployment rates in all countries have unit root. According to the CIPS test results, unemployment rates in MENA countries has unit root. In this context, all the impact of a shock can be seen on the unemployment rate in the mentioned region is permanent. Therefore; it can be said that the current approach of unemployment hysteresis in the region countries are valid.

  11. Understanding the Relative Influence of Anthropogenic Versus Natural Nitrogen on Biogeochemical Processes in the Southern California Bight

    Science.gov (United States)

    McLaughlin, K.; Howard, M. D.; Beck, C. D. A.; Emler, L.; Nezlin, N. P.; Sutula, M.

    2016-02-01

    Nitrogen (N) pollution is considered to be one of the most significant consequences of human-accelerated global change on coastal oceans (Howarth and Marino 2006). In the southern California Bight, wastewater effluent represents 92% of total terrestrial N loading and these loads are equivalent to the "background" N flux from upwelling (Howard et al. 2014). In this study, we attempt to quantify the relative influence of the two dominant nitrogen sources to the Bight (wastewater effluent and upwelled nitrogen) on biogeochemical processes linked to dissolved oxygen, pH and algal blooms. We will compare the sources and fate of nitrogen in an effluent impacted region (offshore of Los Angeles and Orange Counties) to minimally-impacted regions both along the coastline (offshore of Northern San Diego County) and two offshore stations. Key rates of nitrogen and carbon cycling are measured, including primary production and respiration, nitrogen uptake by primary producers, and nitrification. Stable isotope tracer techniques have also been applied to determine the relative influence of effluent versus upwelled nitrogen on biological communities and concentrations. Data generated from this study will be used to validate calculated rate constants used in oceanographic models of ecological response from natural and anthropogenic nutrient inputs in the Bight. These models will be used to estimate the extent to which anthropogenic nutrients are affecting primary production, acidification and hypoxia, as well as which regions are most at risk. They will also be used to analyze management scenarios to understand the effects of anthropogenic nutrient load reductions relative to climate change scenarios.

  12. Procedures as a Representation for Data in a Computer Program for Understanding Natural Language.

    Science.gov (United States)

    Winograd, Terry

    This paper describes a system for the computer understanding of English. The system answers questions, executes commands, and accepts information in normal English dialogue. It uses semantic information and context to understand discourse and to disambiguate sentences. It combines a complete syntactic analysis of each sentence with a heuristic…

  13. Phlebotomine fauna, natural infection rate and feeding habits of Lutzomyia cruzi in Jaciara, state of Mato Grosso, Brazil

    Directory of Open Access Journals (Sweden)

    Veruska Nogueira de Brito

    2014-11-01

    Full Text Available Visceral leishmaniasis (VL in Brazil is transmitted by the phlebotomine Lutzomyia longipalpis and in some midwestern regions by Lutzomyia cruzi. Studies of the phlebotomine fauna, feeding habits and natural infection rate by Leishmania contribute to increased understanding of the epidemiological chain of leishmaniases and their vectorial capacity. Collections were performed in Jaciara, state of Mato Grosso from 2010-2013, during which time 2,011 phlebotomines (23 species were captured (68.70% Lu. cruzi and 20.52% Lutzomyia whitmani. Lu. cruzi females were identified by observing the shapes of the cibarium (a portion of the mouthpart and spermatheca, from which samples were obtained for polymerase chain reaction to determine the rates of natural infection. Engorged phlebotomines were assessed to identify the blood-meal host by ELISA. A moderate correlation was discovered between the number of Lu. cruzi and the temperature and the minimum rate of infection was 6.10%. Twenty-two females were reactive to the antisera of bird (28%, dog (3.30% and skunk (1.60%. We conclude that Lu. cruzi and Lu. whitmani have adapted to the urban environment in this region and that Lu. cruzi is the most likely vector of VL in Jaciara. Moreover, maintenance of Leishmania in the environment is likely aided by the presence of birds and domestic and synanthropic animals.

  14. The nature of the rate-limiting step of blue multicopper oxidases: Homogeneous studies versus heterogeneous

    Directory of Open Access Journals (Sweden)

    Claire Stines-Chaumeil

    2017-06-01

    Full Text Available Multicopper oxidases (MCOs catalyzed two half reactions (linked by an intramolecular electron transfer through a Ping-Pong mechanism: the substrate oxidation followed by the O2 reduction. MCOs have been characterized in details in solution or immobilized on electrode surfaces. The nature of the rate-limiting steps, which is controversial in the literature, is discussed in this mini review for both cases. Deciphering such rate-limiting steps is of particular importance to efficiently use MCOs in any applications requiring the reduction of O2 to water.

  15. Natural radon reduction rate of the community groundwater system in South Korea.

    Science.gov (United States)

    Yun, Uk; Seong Kim, Tae; Kim, Hyun Koo; Kim, Moon Su; Cho, Soo Young; Choo, Chang Oh; Cho, Byong Wook

    2017-08-01

    Tank waters from 13 Community Groundwater Systems (CGS) showed average radon reduction rate of 26.5% (varying from -17.9% to 63.3%). When applying the reduction rate of 26.5% to the nationwide CGS, the percentage of CGS having radon level above 100Bq/L decreases from 28.8% to 22.0%. The natural radon reduction method would be applied to the CGS having radon level slightly exceeding guideline of WHO, as an alternative for aeration or GAC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The natural depuration rate of 137Cs radionuclides in a lichen and moss species

    International Nuclear Information System (INIS)

    Topcuoglu, S.; Dawen, A.M. van; Gungor, N.

    1995-01-01

    Caesium-137 concentrations in lichen and moss samples have been studied for calculations of natural depuration rates. The lichen and moss species were collected from the same trees in western and eastern Black Sea region during the periods of 1987-1992 and 1990-1993, respectively. The natural depuration rates are estimated at biological half-lives. The pattern of depuration results represented by a single component for each non-vascular plant. The biological half-lives of 137 Cs in a lichen and moss samples (Xanthoria parietina and Leucodon immersus) are estimated to be 5.86 and 10.9 months, respectively. This work set supports the view that radioactivity monitoring in lichens can be a more useful monitor than mosses to determine the lasting effect of radioactive fallout. (author)

  17. Improvement in understanding of natural circulation phenomena in water cooled nuclear power plants

    International Nuclear Information System (INIS)

    Choi, Jong-Ho; Cleveland, John; Aksan, Nusret

    2011-01-01

    Highlights: ► Phenomena influencing natural circulation in passive systems. ► Behaviour in large pools of liquid. ► Effect of non-condensable gas on condensation heat transfer. ► Behaviour of containment emergency systems. ► Natural circulation flow and pressure drop in various geometries. - Abstract: The IAEA has organized a coordinated research project (CRP) on “Natural Circulation Phenomena, Modelling, and Reliability of Passive Systems That Utilize Natural Circulation.” Specific objectives of CRP were to (i) establish the status of knowledge: reactor start-up and operation, passive system initiation and operation, flow stability, 3-D effects, and scaling laws, (ii) investigate phenomena influencing reliability of passive natural circulation systems, (iii) review experimental databases for the phenomena, (iv) examine the ability of computer codes to predict natural circulation and related phenomena, and (v) apply methodologies for examining the reliability of passive systems. Sixteen institutes from 13 IAEA Member States have participated in this CRP. Twenty reference advanced water cooled reactor designs including evolutionary and innovative designs were selected to examine the use of natural circulation and passive systems in their designs. Twelve phenomena influencing natural circulation were identified and characterized: (1) behaviour in large pools of liquid, (2) effect of non-condensable gases on condensation heat transfer, (3) condensation on the containment structures, (4) behaviour of containment emergency systems, (5) thermo-fluid dynamics and pressure drops in various geometrical configurations, (6) natural circulation in closed loop, (7) steam liquid interaction, (8) gravity driven cooling and accumulator behaviour, (9) liquid temperature stratification, (10) behaviour of emergency heat exchangers and isolation condensers, (11) stratification and mixing of boron, and (12) core make-up tank behaviour. This paper summarizes the

  18. Rate and Time Trend of Perinatal, Infant, Maternal Mortality, Natality and Natural Population Growth in Kosovo

    OpenAIRE

    Azemi, Mehmedali; Gashi, Sanije; Berisha, Majlinda; Kolgeci, Selim; Ismaili-Jaha, Vlora

    2012-01-01

    Aim: The aim of work has been the presentation of the rate and time trends of some indicators of the heath condition of mothers and children in Kosovo: fetal mortality, early neonatal mortality, perinatal mortality, infant mortality, natality, natural growth of population etc. The treated patients were the newborn and infants in the post neonatal period, women during their pregnancy and those 42 days before and after the delivery. Methods: The data were taken from: register of the patients tr...

  19. Computational Fluid Dynamics Modeling to Improve Natural Flow Rate and Sweet Pepper Productivity in Greenhouse

    OpenAIRE

    W. Limtrakarn; P. Boonmongkol; A. Chompupoung; K. Rungprateepthaworn; J. Kruenate; P. Dechaumphai

    2012-01-01

    Natural flow rate and sweet peppers productivity in tropical greenhouse are improved by CFD simulation is the main objective of this research work. Most of the greenhouse types today are in the arch shape. To develop an improved greenhouse structure for the region, the arch type was built and used as the control model. Mae Sar Mai agriculture research station under the royal project foundation was selected as the field test site. Temperature sensors with data logger were installed to monitor ...

  20. Understanding Racial and Ethnic Disparities in U.S. Infant Mortality Rates

    Science.gov (United States)

    ... mortality rates for sudden infant death syndrome (SIDS), congenital malformations, and unintentional injuries were also substantially higher for ... infant mortality rate. SIDS accounted for 6 percent, congenital malformations 5 percent, and unintentional injuries 4 percent of ...

  1. The Impact of Designing and Evaluating Molecular Animations on How Well Middle School Students Understand the Particulate Nature of Matter

    Science.gov (United States)

    Chang, Hsin-Yi; Quintana, Chris; Krajcik, Joseph S.

    2010-01-01

    In this study, we investigated whether the understanding of the particulate nature of matter by students was improved by allowing them to design and evaluate molecular animations of chemical phenomena. We developed Chemation, a learner-centered animation tool, to allow seventh-grade students to construct flipbook-like simple animations to show…

  2. Effectiveness of Science-Technology-Society (STS) Instruction on Student Understanding of the Nature of Science and Attitudes toward Science

    Science.gov (United States)

    Akcay, Behiye; Akcay, Hakan

    2015-01-01

    The study reports on an investigation about the impact of science-technology-society (STS) instruction on middle school student understanding of the nature of science (NOS) and attitudes toward science compared to students taught by the same teacher using traditional textbook-oriented instruction. Eight lead teachers used STS instruction an…

  3. Do Pre-Service Science Teachers Have Understanding of the Nature of Science?: Explicit-Reflective Approach

    Science.gov (United States)

    Örnek, Funda; Turkey, Kocaeli

    2014-01-01

    Current approaches in Science Education attempt to enable students to develop an understanding of the nature of science, develop fundamental scientific concepts, and develop the ability to structure, analyze, reason, and communicate effectively. Students pose, solve, and interpret scientific problems, and eventually set goals and regulate their…

  4. Explicitly Targeting Pre-Service Teacher Scientific Reasoning Abilities and Understanding of Nature of Science through an Introductory Science Course

    Science.gov (United States)

    Koenig, Kathleen; Schen, Melissa; Bao, Lei

    2012-01-01

    Development of a scientifically literate citizenry has become a national focus and highlights the need for K-12 students to develop a solid foundation of scientific reasoning abilities and an understanding of nature of science, along with appropriate content knowledge. This implies that teachers must also be competent in these areas; but…

  5. Using 238U/235U ratios to understand the formation and oxidation of reduced uranium solids in naturally reduced zones

    Science.gov (United States)

    Jemison, N.; Johnson, T. M.; Druhan, J. L.; Davis, J. A.

    2016-12-01

    Uranium occurs in groundwater primarily as soluble and mobile U(VI), which can be reduced to immobile U(IV), often observed in sediments as uraninite. Numerous U(VI)-contaminated sites, such as the DOE field site in Rifle, CO, contain naturally reduced zones (NRZ's) that have relatively high concentrations of organic matter. Reduction of heavy metals occurs within NRZ's, producing elevated concentrations of iron sulfides and U(IV). Slow, natural oxidation of U(IV) from NRZ's may prolong U(VI) contamination of groundwater. The reduction of U(VI) produces U(IV) with a higher 238U/235U ratio. Samples from two NRZ sediment cores recovered from the Rifle site revealed that the outer fringes of the NRZ contain U(IV) with a high 238U/235U ratio, while lower values are observed in the center . We suggest that as aqueous U(VI) was reduced in the NRZ, it was driven to lower 238U/235U values, such that U(IV) formed in the core of the NRZ reflects a lower 238U/235U. Two oxidation experiments were conducted by injecting groundwater containing between 14.9 and 21.2 mg/L dissolved O2 as an oxidant into the NRZ. The oxidation of U(IV) from this NRZ increased aqueous U(VI) concentrations and caused a shift to higher 238U/235U in groundwater as U(IV) was oxidized primarily on the outer fringes of the NRZ. In total these observations suggest that the stability of solid phase uranium is governed by coupled reaction and transport processes. To better understand various reactive transport scenarios we developed a model for the formation and oxidation of NRZ's utilizing the reactive transport software CrunchTope. These simulations suggest that the development of isotopically heterogeneous U(IV) within NRZ's is largely controlled by permeability of the NRZ and the U(VI) reduction rate. Oxidation of U(IV) from the NRZ's is constrained by the oxidation rate of U(IV) as well as iron sulfides, which can prevent oxidation of U(IV) by scavenging dissolved oxygen.

  6. The natural number bias and its role in rational number understanding in children with dyscalculia. Delay or deficit?

    Science.gov (United States)

    Van Hoof, Jo; Verschaffel, Lieven; Ghesquière, Pol; Van Dooren, Wim

    2017-12-01

    Previous research indicated that in several cases learners' errors on rational number tasks can be attributed to learners' tendency to (wrongly) apply natural number properties. There exists a large body of literature both on learners' struggle with understanding the rational number system and on the role of the natural number bias in this struggle. However, little is known about this phenomenon in learners with dyscalculia. We investigated the rational number understanding of learners with dyscalculia and compared it with the rational number understanding of learners without dyscalculia. Three groups of learners were included: sixth graders with dyscalculia, a chronological age match group, and an ability match group. The results showed that the rational number understanding of learners with dyscalculia is significantly lower than that of typically developing peers, but not significantly different from younger learners, even after statistically controlling for mathematics achievement. Next to a delay in their mathematics achievement, learners with dyscalculia seem to have an extra delay in their rational number understanding, compared with peers. This is especially the case in those rational number tasks where one has to inhibit natural number knowledge to come to the right answer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Long-term flow-through column experiments and their relevance to natural granitoid weathering rates

    Science.gov (United States)

    White, Art F.; Schulz, Marjorie S.; Lawrence, Corey R.; Vivit, Davison V.; Stonestrom, David A.

    2017-04-01

    Four pairs of fresh and partly-weathered granitoids, obtained from well-characterized watersheds-Merced River, CA, USA; Panola, GA, USA; Loch Vale, CO, USA, and Rio Icacos, Puerto Rico-were reacted in columns under ambient laboratory conditions for 13.8 yrs, the longest running experimental weathering study to date. Low total column mass losses (column experiments. Fresh granitoid effluent solute concentrations initially declined rapidly, followed by much slower decreases over the next decade. Weathered granitoid effluent concentrations increased modestly over the same time period, indicating losses of natural Fe-oxide and/or clay coatings and the increased exposure of primary mineral surfaces. Corresponding (fresh and weathered) elemental effluent concentrations trended toward convergence during the last decade of reaction. NETPATH/PHREEQC code simulations indicated non-stoichiometric dissolution involving Ca release from disseminated calcite and excess K release from interlayer biotite. Effluent 87Sr/85Sr ratios reflected a progressive weathering sequence beginning and ending with 87Sr/85Sr values of plagioclase with an additional calcite input and a radiogenic biotite excursion proportional to the granitoid ages. Effluents became thermodynamically saturated with goethite and gibbsite, slightly under-saturated with kaolinite and strongly under-saturated with plagioclase, consistent with kinetically-limited weathering in which solutes such as Na varied with column flow rates. Effluent Na concentrations showed no clear trend with time during the last decade of reaction (fresh granitoids) or increased slowly with time (weathered granitoids). Analysis of cumulative Na release indicated that plagioclase dissolution achieved steady state in 3 of the 4 fresh granitoids during the last decade of reaction. Surface-area normalized plagioclase dissolution rates exhibited a narrow range (0.95-1.26 10-13 moles m-2 s-1), in spite of significant stoichiometric differences (An0

  8. Orion Versus Poseidon: Understanding How Nasa's Crewed Capsule Survives Nature's Fury

    Science.gov (United States)

    Barbre, Robert E., Jr.

    2016-01-01

    This presentation summarizes the Marshall Space Flight Center Natural Environments Terrestrial and Planetary Environments (TPE) Team support to the NASA Orion space vehicle. The Orion vehicle, part of the Multi-Purpose Crew Vehicle Program, is designed to carry astronauts beyond low-Earth orbit and is currently undergoing a series of tests including Exploration Flight Test (EFT)-1. This design must address the natural environment to which the capsule and launch vehicle are exposed during all mission phases. In addition, the design must, to the best extent possible, implement the same process and data to be utilized on launch day. The TPE utilizes meteorological data to assess the sensitivities of the vehicle due to the terrestrial environment. The presentation describes examples of TPE support for vehicle design and several tests, as well as support for EFT-1 and planning for upcoming Exploration Missions while emphasizing the importance of accounting for the natural environment's impact to the vehicle early in the vehicle's program.

  9. Gamma-ray dose-rates to human tissues from natural external sources in Great Britain

    International Nuclear Information System (INIS)

    Spiers, F.W.

    1960-01-01

    The information on environmental gamma radiation given in the last report (Spiers, 1956) was limited by the small amount of experimental data then available. Considerably more information has been accumulated since then and a summary has been published in the Report of the United Nations Scientific Committee on te Effects of Atomic Radiation 1958). The data reported from Austria, France, Sweden and the U.S.A. show that in general dose-rates out-of-doors range from about 0 mrads per year over sedimentary rocks to about 200 mrads per year in granite districts. In houses a similar range of doserates is indicated, the rates in individual houses depending upon the nature of the building materials. In some parts of the world, however, very much higher dose-rates have been observed. On the extensive area of monazite sand in the Kerala State of India dose-rates of up to 4000 mrads per year have been recorded and the mean dose-rate for 10 villages with a total population of 52,000 has been estimated to be 1270 mrads per year. Mean dose-rates of 500 and 1600 mrads per year have also been reported from two localities in Brazil

  10. Litter Decomposition Rate of Avicennia marina and Rhizophora apiculata in Pulau Dua Nature Reserve, Banten

    Directory of Open Access Journals (Sweden)

    Febriana Siska

    2016-05-01

    Full Text Available Litter decomposition rate is useful method to determine forest fertility level. The aims of this study were to measure decomposition rate, and analyze the nutrient content released organic carbon, nitrogen, and phosphor from Avicennia marina and Rhizophora apiculata litters during the decomposition process. The research was conducted in the Pulau Dua Nature Reserve, Serang-Banten on A. marina and R. apiculata forest communities. Litter decomposition rate measurements performed in the field. Litter that has been obtained with the trap system is inserted into litter bag and than tied to the roots or trees to avoid drifting sea water. Litter decomposition rate was measured every 15 days and is accompanied by analysis of the content of organic C , total N and P. Our research results showed decomposition rate of A. marina (k= 0.83 was higher than that of R. apiculata (k= 0.41. Differences of  leaf anatomical structure and sea water salinity  influenced to the rate of litter decomposition. Organic C released was declined with longer of litter decomposition, on the contrary of releasing N and P nutrients.

  11. Recent Progress in Understanding Natural-Hazards-Generated TEC Perturbations: Measurements and Modeling Results

    Science.gov (United States)

    Komjathy, A.; Yang, Y. M.; Meng, X.; Verkhoglyadova, O. P.; Mannucci, A. J.; Langley, R. B.

    2015-12-01

    Natural hazards, including earthquakes, volcanic eruptions, and tsunamis, have been significant threats to humans throughout recorded history. The Global Positioning System satellites have become primary sensors to measure signatures associated with such natural hazards. These signatures typically include GPS-derived seismic deformation measurements, co-seismic vertical displacements, and real-time GPS-derived ocean buoy positioning estimates. Another way to use GPS observables is to compute the ionospheric total electron content (TEC) to measure and monitor post-seismic ionospheric disturbances caused by earthquakes, volcanic eruptions, and tsunamis. Research at the University of New Brunswick (UNB) laid the foundations to model the three-dimensional ionosphere at NASA's Jet Propulsion Laboratory by ingesting ground- and space-based GPS measurements into the state-of-the-art Global Assimilative Ionosphere Modeling (GAIM) software. As an outcome of the UNB and NASA research, new and innovative GPS applications have been invented including the use of ionospheric measurements to detect tiny fluctuations in the GPS signals between the spacecraft and GPS receivers caused by natural hazards occurring on or near the Earth's surface.We will show examples for early detection of natural hazards generated ionospheric signatures using ground-based and space-borne GPS receivers. We will also discuss recent results from the U.S. Real-time Earthquake Analysis for Disaster Mitigation Network (READI) exercises utilizing our algorithms. By studying the propagation properties of ionospheric perturbations generated by natural hazards along with applying sophisticated first-principles physics-based modeling, we are on track to develop new technologies that can potentially save human lives and minimize property damage. It is also expected that ionospheric monitoring of TEC perturbations might become an integral part of existing natural hazards warning systems.

  12. Rate and time trend of perinatal, infant, maternal mortality, natality and natural population growth in kosovo.

    Science.gov (United States)

    Azemi, Mehmedali; Gashi, Sanije; Berisha, Majlinda; Kolgeci, Selim; Ismaili-Jaha, Vlora

    2012-01-01

    THE AIM OF WORK HAS BEEN THE PRESENTATION OF THE RATE AND TIME TRENDS OF SOME INDICATORS OF THE HEATH CONDITION OF MOTHERS AND CHILDREN IN KOSOVO: fetal mortality, early neonatal mortality, perinatal mortality, infant mortality, natality, natural growth of population etc. The treated patients were the newborn and infants in the post neonatal period, women during their pregnancy and those 42 days before and after the delivery. THE DATA WERE TAKEN FROM: register of the patients treated in the Pediatric Clinic of Prishtina, World Health Organization, Mother and Child Health Care, Reproductive Health Care, Ministry of Health of the Republic of Kosovo, Statistical Department of Kosovo, the National Institute of Public Health and several academic texts in the field of pediatrics. Some indicators were analyzed in a period between year 1945-2010 and 1950-2010, whereas some others were analyzed in a time period between year 2000 and 2011. The perinatal mortality rate in 2000 was 29.1‰, whereas in 2011 it was 18.7‰. The fetal mortality rate was 14.5‰ during the year 2000, whereas in 2011 it was 11.0‰, in 2000 the early neonatal mortality was 14.8‰, in 2011 it was 7.5‰. The infant mortality in Kosovo was 164‰ in 1950, whereas in 2010 it was 20.5‰. The most frequent causes of infant mortality have been: lower respiratory tract infections, acute infective diarrhea, perinatal causes, congenital malformations and unclassified conditions. Maternal death rate varied during this time period. Maternal death in 2000 was 23 whereas in 2010 only two cases were reported. Regarding the natality, in 1950 it reached 46.1 ‰, whereas in 2010 it reached 14‰, natural growth of population rate in Kosovo was 29.1‰ in 1950, whereas in 2011 it was 11.0‰. Perinatal mortality rate in Kosovo is still high in comparison with other European countries (Turkey and Kyrgyzstan have the highest perinatal mortality rate), even though it is in a continuous decrease. Infant mortality

  13. Rate and Time Trend of Perinatal, Infant, Maternal Mortality, Natality and Natural Population Growth in Kosovo

    Science.gov (United States)

    Azemi, Mehmedali; Gashi, Sanije; Berisha, Majlinda; Kolgeci, Selim; Ismaili-Jaha, Vlora

    2012-01-01

    Aim: The aim of work has been the presentation of the rate and time trends of some indicators of the heath condition of mothers and children in Kosovo: fetal mortality, early neonatal mortality, perinatal mortality, infant mortality, natality, natural growth of population etc. The treated patients were the newborn and infants in the post neonatal period, women during their pregnancy and those 42 days before and after the delivery. Methods: The data were taken from: register of the patients treated in the Pediatric Clinic of Prishtina, World Health Organization, Mother and Child Health Care, Reproductive Health Care, Ministry of Health of the Republic of Kosovo, Statistical Department of Kosovo, the National Institute of Public Health and several academic texts in the field of pediatrics. Some indicators were analyzed in a period between year 1945-2010 and 1950-2010, whereas some others were analyzed in a time period between year 2000 and 2011. Results: The perinatal mortality rate in 2000 was 29.1‰, whereas in 2011 it was 18.7‰. The fetal mortality rate was 14.5‰ during the year 2000, whereas in 2011 it was 11.0‰, in 2000 the early neonatal mortality was 14.8‰, in 2011 it was 7.5‰. The infant mortality in Kosovo was 164‰ in 1950, whereas in 2010 it was 20.5‰. The most frequent causes of infant mortality have been: lower respiratory tract infections, acute infective diarrhea, perinatal causes, congenital malformations and unclassified conditions. Maternal death rate varied during this time period. Maternal death in 2000 was 23 whereas in 2010 only two cases were reported. Regarding the natality, in 1950 it reached 46.1 ‰, whereas in 2010 it reached 14‰, natural growth of population rate in Kosovo was 29.1‰ in 1950, whereas in 2011 it was 11.0‰. Conclusion: Perinatal mortality rate in Kosovo is still high in comparison with other European countries (Turkey and Kyrgyzstan have the highest perinatal mortality rate), even though it is in a

  14. Understanding the Disproportionately Low Marriage Rate among African Americans: An Amalgam of Sociological and Psychological Constraints

    Science.gov (United States)

    Chambers, Anthony L.; Kravitz, Aliza

    2011-01-01

    African Americans have the lowest marriage rate of any racial and ethnic group in America. Although the low marriage rate among African Americans has been largely examined through a sociological lens by documenting structural barriers, which has important policy implications, researchers have not sufficiently examined the psychological and…

  15. Understanding the Nature of Local-Global Interactions in Istanbul’s Retail Property Market

    Directory of Open Access Journals (Sweden)

    Fatih Eren

    2014-07-01

    Full Text Available Today, capital, people and information flows have increased more than ever before among different regions in the world. Every flow creates a different local-global interaction in its own social environment. One of social environments in which this kind of interactions occurs is property markets. There are some theories to explain the nature of local and global interactions in social sciences literature. However, the success of these theories in explaining the nature of local-global interactions in a property market became subject to a research very few. This research aims to make a contribution to this area. The study also intends to find general answers to some important questions emerge in the internationalization process of property markets. The study focuses on the three well-accepted interaction theories of social sciences, which are imperialism, globalisation and glocalisation. The validity of the assumptions of these theories in the case of Istanbul’s retail property market is questioned in this research. The emergence of social structures and the specific behaviours of these structures in local property markets may be understood better when true point of view is found out about interactions. A qualitative methodology is followed; interview and document analysis methods are used in the study. Findings show that the nature of local-global interactions experienced in Istanbul’s retail property market is very unique so it is not possible to explain this unique nature using the perspective of only one settled theory.

  16. Freezing Point of Milk: A Natural Way to Understand Colligative Properties

    Science.gov (United States)

    Novo, Mercedes; Reija, Belen; Al-Soufi, Wajih

    2007-01-01

    A laboratory experiment is presented in which the freezing point depression is analyzed using milk as solution. The nature of milk as a mixture of different solutes makes it a suitable probe to learn about colligative properties. The first part of the experiment illustrates the analytical use of freezing point measurements to control milk quality,…

  17. Speech perception and reading: two parallel modes of understanding language and implications for acquiring literacy naturally.

    Science.gov (United States)

    Massaro, Dominic W

    2012-01-01

    I review 2 seminal research reports published in this journal during its second decade more than a century ago. Given psychology's subdisciplines, they would not normally be reviewed together because one involves reading and the other speech perception. The small amount of interaction between these domains might have limited research and theoretical progress. In fact, the 2 early research reports revealed common processes involved in these 2 forms of language processing. Their illustration of the role of Wundt's apperceptive process in reading and speech perception anticipated descriptions of contemporary theories of pattern recognition, such as the fuzzy logical model of perception. Based on the commonalities between reading and listening, one can question why they have been viewed so differently. It is commonly believed that learning to read requires formal instruction and schooling, whereas spoken language is acquired from birth onward through natural interactions with people who talk. Most researchers and educators believe that spoken language is acquired naturally from birth onward and even prenatally. Learning to read, on the other hand, is not possible until the child has acquired spoken language, reaches school age, and receives formal instruction. If an appropriate form of written text is made available early in a child's life, however, the current hypothesis is that reading will also be learned inductively and emerge naturally, with no significant negative consequences. If this proposal is true, it should soon be possible to create an interactive system, Technology Assisted Reading Acquisition, to allow children to acquire literacy naturally.

  18. Influences of Teleological and Lamarckian Thinking on Student Understanding of Natural Selection

    Science.gov (United States)

    Stover, Shawn K.; Mabry, Michelle L.

    2007-01-01

    Previous research has demonstrated creationist, Lamarckian, and teleological reasoning in high school and college students. These lines of thinking conflict with the Darwinian notion of natural selection, which serves as the primary catalyst for biological evolution. The current study assessed evolutionary conceptions in non-science majors,…

  19. From landscapes to soundscapes: understanding and managing natural quiet in the national parks

    Science.gov (United States)

    Robert Manning; William Valliere; Jeffery Hallo; Peter Newman; Ericka Pilcher; Michael Savidge; Dan Dugan

    2007-01-01

    Research at Muir Woods Natural Monument suggests that soundscapes are an important component of parks and outdoor recreation, that human-caused noise is a potentially important indicator of quality for park soundscapes, and that visitors have normative standards for the maximum acceptable level of human-caused noise in parks. Formulating indicators and standards of...

  20. Developing Conceptual Understanding of Natural Selection: The Role of Interest, Efficacy, and Basic Prior Knowledge

    Science.gov (United States)

    Linnenbrink-Garcia, Lisa; Pugh, Kevin J.; Koskey, Kristin L. K.; Stewart, Victoria C.

    2012-01-01

    Changes in high school students' (n = 94) conceptions of natural selection were examined as a function of motivational beliefs (individual interest, academic self-efficacy), basic prior knowledge, and gender across three assessments (pre, post, follow-up). Results from variable-centered analyses suggested that these variables had relatively little…

  1. Understanding the Views of the Nature of Science of Undergraduate Science, Technology, Engineering, and Mathematics Students

    Science.gov (United States)

    Hypolite, Karen L.

    2012-01-01

    Much of the nature of science research has been focused on high school students. High school students are primarily the target of such research to aid and to guide them in making informed decisions about possible career choices in the sciences (Bell, Blair, Crawford, & Lederman, 2002). Moreover, during review of the literature, little to no…

  2. Changes in Pre-service Science Teachers' Understandings After Being Involved in Explicit Nature of Science and Socioscientific Argumentation Processes

    Science.gov (United States)

    Kutluca, A. Y.; Aydın, A.

    2017-08-01

    The study explored the changes in pre-service science teachers' understanding of the nature of science and their opinions about the nature of science, science teaching and argumentation after their participation in explicit nature of science (NOS) and socioscientific argumentation processes. The participants were 56 third-grade pre-service science teachers studying in a state university in Turkey. The treatment group comprised 27 participants, and there were 29 participants in the comparison group. The comparison group participants were involved in a student-centred science-teaching process, and the participants of the treatment group were involved in explicit NOS and socioscientific argumentation processes. In the study, which lasted a total of 11 weeks, a NOS-as-argumentation questionnaire was administered to all the participants to determine their understanding of NOS at the beginning and end of the data collection process, and six random participants of the treatment group participated in semi-structured interview questions in order to further understand their views regarding NOS, science teaching and argumentation. Qualitative and quantitative data analysis revealed that the explicit NOS and socioscientific argumentation processes had a significant effect on pre-service science teachers' NOS understandings. Furthermore, NOS, argumentation and science teaching views of the participants in the treatment group showed a positive change. The results of this study are discussed in light of the related literature, and suggestions are made within the context of contribution to science-teaching literature, improvement of education quality and education of pre-service teachers.

  3. Toward mechanistic understanding of the relationship between the sound absorption and the natural and resonant frequencies of porous media.

    Science.gov (United States)

    Hasani Baferani, A; Ohadi, A R; Keshavarz, R

    2016-12-01

    In this paper, the natural and resonant frequencies of porous media are studied based on Biot's equations. The governing equations of porous media are analytically solved by using the recent developed potential function method. Based on the obtained results, the natural and resonant frequencies of the porous medium can be investigated. In this research, several foams with different acoustical and non-acoustical properties are considered and the natural and resonant frequencies are studied. In addition, for a better understanding of the natural and variation of resonant frequencies of the considered foams, various damping gains are defined and by changing them gradually, the variations of absorption coefficient and field variables are studied. The results show that the trends of absorption coefficient versus frequency for porous media can be predicted by considering the arrangement of structural and fluid natural frequencies. Also, around the structural natural frequencies two types of variations in absorption coefficient occur (i.e., maximum-minimum or maximum variations). Additionally, after computing the corresponding results of rigid frame and Biot's models it can be seen that the rigid frame theory cannot correctly predict the sound absorption coefficient in the vicinity of structural natural frequencies.

  4. Instruments of Inquiry: Understanding the Nature and Role of Design Tools

    DEFF Research Database (Denmark)

    Dalsgaard, Peter

    2017-01-01

    Designers employ a range of tools in most design projects, yet there are few frameworks for understanding how and why they work. On the basis of a well-established school of thought, pragmatism, this paper contributes with a coherent conceptualisation of tools in design, which I label instruments...

  5. 21 Ideas: A 42-Year Search to Understand the Nature of Giftedness

    Science.gov (United States)

    Sternberg, Robert J.

    2018-01-01

    In this article, I describe the 21 ideas underlying a 42-year search to understand giftedness. I present the ideas roughly chronologically, in the order in which they arose, and discuss how in a career as in science, progress means supplementing or even superseding one idea with the next. In terms of the 21 ideas, I start with a discussion of how…

  6. Laboratory Activities to Support Student Understanding of the Molecular Mechanisms of Mutation & Natural Selection

    Science.gov (United States)

    Hubler, Tina; Adams, Patti; Scammell, Jonathan

    2015-01-01

    The molecular basis of evolution is an important and challenging concept for students to understand. In a previous article, we provided some of the scientific background necessary to teach this topic. This article features a series of laboratory activities demonstrating that molecular events can alter the genomes of organisms. These activities are…

  7. Low Rate of Prenatal Diagnosis among Neonates with Critical Aortic Stenosis: Insight into the Natural History In Utero (Aortic Stenosis)

    Science.gov (United States)

    Freud, Lindsay R.; Moon-Grady, Anita; Escobar-Diaz, Maria C.; Gotteiner, Nina L.; Young, Luciana T.; McElhinney, Doff B.; Tworetzky, Wayne

    2014-01-01

    Objectives To better understand the natural history and spectrum of fetal aortic stenosis (AS), we aimed to 1) determine the prenatal diagnosis rate of neonates with critical AS and a biventricular (BV) outcome; and 2) describe the findings at fetal echocardiography in prenatally diagnosed patients. Methods A multi-center, retrospective study was performed from 2000 to 2013. Neonates with critical AS who were discharged with a BV outcome were included. The prenatal diagnosis rate was compared to that reported for hypoplastic left heart syndrome (HLHS). Fetal echocardiographic findings in prenatally diagnosed patients were reviewed. Results Only 10 of 117 neonates (8.5%) with critical AS and a BV outcome were diagnosed prenatally, a rate significantly lower than that for HLHS in the contemporary era (82%; p<0.0001). Of the 10 patients diagnosed prenatally, all developed LV dysfunction by a median gestational age of 33 weeks (range, 28–35). When present, Doppler abnormalities such as retrograde flow in the aortic arch (n=2), monophasic mitral inflow (n=2), and left to right flow across the foramen ovale (n=8) developed late in gestation (median 33 weeks). Conclusion The prenatal diagnosis rate among neonates with critical AS and a BV outcome is very low, likely due to a relatively normal 4-chamber view in mid-gestation with development of significant obstruction in the 3rd trimester. This natural history contrasts with that of severe mid-gestation AS with evolving HLHS and suggests that the timing in gestation of significant AS has an important impact on subsequent left heart growth in utero. PMID:25251721

  8. A cross-national study of the association between natural resource rents and homicide rates, 2000–12

    Science.gov (United States)

    Stretesky, Paul B.; Long, Michael A.; Lynch, Michael J.

    2016-01-01

    Countries that rely on natural resource rents (that is, the revenue generated from the sale of natural resources) may suffer from a variety of social problems. This exploratory study reviews the natural resource extraction literature to derive a ‘natural resource rents–homicide’ hypothesis. Data for 173 countries for the years 2000 to 2012 are examined to determine if there is a correlation between natural resource rents and homicide rates. Multilevel growth models suggest that natural resource rents are positively correlated with homicide rates within countries (level 1) but not between them (level 2). Importantly, the correlation between natural resource rents and homicide is strongest when natural resource rents are lagged. We conclude by suggesting that increasing natural resource rents may be counterproductive over the long run and sow the seeds for a future increase in homicide. PMID:28781581

  9. Understanding the nature and threats of drug trafficking to national and regional security in West Africa

    Directory of Open Access Journals (Sweden)

    Kwesi Aning

    2014-02-01

    Full Text Available Several West African states are threatened by increasingly powerful transnational organised criminal networks. Yet, scholarly work on the nature, characteristics and strength of these groups and how their activities threaten states remains sparse, leading to misunderstandings and inadequate appreciation of the precise nature of the threats they pose to West Africa. This paper seeks to fill these lacunae in our knowledge. It focuses on the nexus between drugs, crime and terrorism. It argues that, the financial spin-offs from criminal activities contribute to the development of opportunistic relationships between criminals and extremist groups that threatens West Africa’s fragile states. The analyses are based on evidence from several West African states, but employ the ongoing crisis in the Sahel, particularly Mali, as an empirical case, to demonstrate how ‘profitable collusion’ among different actors permits hollow states to become edifices that allows corruption, criminality and impunity to flourish.

  10. Framing the conversation: use of PRECIS-2 ratings to advance understanding of pragmatic trial design domains.

    Science.gov (United States)

    Lipman, Paula Darby; Loudon, Kirsty; Dluzak, Leanora; Moloney, Rachael; Messner, Donna; Stoney, Catherine M

    2017-11-10

    There continues to be debate about what constitutes a pragmatic trial and how it is distinguished from more traditional explanatory trials. The NIH Pragmatic Trials Collaborative Project, which includes five trials and a coordinating unit, has adopted the Pragmatic-Explanatory Continuum Indicator Summary (PRECIS-2) instrument. The purpose of the study was to collect PRECIS-2 ratings at two points in time to assess whether the tool was sensitive to change in trial design, and to explore with investigators the rationale for rating shifts. A mixed-methods design included sequential collection and analysis of quantitative data (PRECIS-2 ratings) and qualitative data. Ratings were collected at two annual, in-person project meetings, and subsequent interviews conducted with investigators were recorded, transcribed, and coded using NVivo 11 Pro for Windows. Rating shifts were coded as either (1) actual change (reflects a change in procedure or protocol), (2) primarily a rating shift reflecting rater variability, or (3) themes that reflect important concepts about the tool and/or pragmatic trial design. Based on PRECIS-2 ratings, each trial was highly pragmatic at the planning phase and remained so 1 year later in the early phases of trial implementation. Over half of the 45 paired ratings for the nine PRECIS-2 domains indicated a rating change from Time 1 to Time 2 (N = 24, 53%). Of the 24 rating changes, only three represented a true change in the design of the trial. Analysis of rationales for rating shifts identified critical themes associated with the tool or pragmatic trial design more generally. Each trial contributed one or more relevant comments, with Eligibility, Flexibility of Adherence, and Follow-up each accounting for more than one. PRECIS-2 has proved useful for "framing the conversation" about trial design among members of the Pragmatic Trials Collaborative Project. Our findings suggest that design elements assessed by the PRECIS-2 tool may represent

  11. Human Computer Collaboration at the Edge: Enhancing Collective Situation Understanding with Controlled Natural Language

    Science.gov (United States)

    2016-09-06

    has conceptually noted lim- itations of COPs [26]; our research empirically illustrates the tradeoffs with a COP even if all users have a shared goal...in group size and dynamics. To further assess the effects of a COP on information quality and quantity, we plan to run a conceptual replication of the...2] T. Kuhn, “A survey and classification of controlled natural languages,” Computational Linguistics , vol. 40, pp. 121–170, 2014. [3] E. Cambria

  12. Understanding the oil price-exchange rate nexus for the Fiji islands

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Paresh Kumar [School of Accounting, Economics and Finance, Faculty of Business and Law, Deakin University, Melbourne (Australia); Narayan, Seema [School of Economics, Finance and Marketing, Royal Melbourne Institute of Technology, Melbourne (Australia); Prasad, Arti [Department of Economics, Faculty of Business and Economics, Monash University (Australia)

    2008-09-15

    In this paper, we examine the relationship between oil price and the Fiji-US exchange rate using daily data for the period 2000-2006. We use the generalised autoregressive conditional heteroskedasticity (GARCH) and exponential GARCH (EGARCH) models to estimate the impact of oil price on the nominal exchange rate. We find that a rise in oil prices leads to an appreciation of the Fijian dollar vis-a-vis the US dollar. (author)

  13. Understanding the oil price-exchange rate nexus for the Fiji islands

    International Nuclear Information System (INIS)

    Narayan, Paresh Kumar; Narayan, Seema; Prasad, Arti

    2008-01-01

    In this paper, we examine the relationship between oil price and the Fiji-US exchange rate using daily data for the period 2000-2006. We use the generalised autoregressive conditional heteroskedasticity (GARCH) and exponential GARCH (EGARCH) models to estimate the impact of oil price on the nominal exchange rate. We find that a rise in oil prices leads to an appreciation of the Fijian dollar vis-a-vis the US dollar. (author)

  14. Understanding ecosystem services adoption by natural resource managers and research ecologists

    Science.gov (United States)

    Engel, Daniel; Evans, Mary; Low, Bobbi S.; Schaeffer, Jeff

    2017-01-01

    The ecosystem services (ES) paradigm has gained much traction as a natural resource management approach due to its comprehensive nature and ability to provide quantitative tools to improve decision-making. However, it is still uncertain whether and how practitioners have adopted the ES paradigm into their work and how this aligns with resource management information needs. To address this, we surveyed natural resource managers within the Great Lakes region about their use of ES information in decision-making. We complemented our manager survey with in-depth interviews of a related population—research ecologists at the U.S. Geological Survey Great Lakes Science Center. In this study, managers and ecologists almost unanimously agreed that ES were appropriate to consider in resource management. We also found high congruence between managers and ecologists in the ES considered most relevant to their work, with provision of habitat, recreation and tourism, biological control, and primary production being the ES ranked highly by both groups. However, a disconnect arose when research ecologists deemed the information they provide regarding ES as adequate for management needs, but managers disagreed. Furthermore, managers reported that they would use economic information about ES if they had access to that information. We believe this data deficiency could represent a gap in scientific coverage by ecologists, but it may also simply reflect an underrepresentation of ecological economists who can translate ecological knowledge of ES providers into economic information that many managers desired.

  15. Research and Teaching: Factors Related to College Students' Understanding of the Nature of Science--Comparison of Science Majors and Nonscience Majors

    Science.gov (United States)

    Partin, Matthew L.; Underwood, Eileen M.; Worch, Eric A.

    2013-01-01

    To develop a more scientifically literate society, students need to understand the nature of science, which may be affected by controversial topics such as evolution. There are conflicting views among researchers concerning the relationships between understanding evolution, acceptance of evolution, and understanding of the nature of science. Four…

  16. Dialectical Reason and Necessary Conflict—Understanding and the Nature of Terror

    Directory of Open Access Journals (Sweden)

    Angelica Nuzzo

    2007-12-01

    Full Text Available Taking as point of departure Hegelrsquo;s early reflections on his historical present, this essay examines the relationship between dialectical reason and the activity of the understanding in generating contradiction. Dialecticmdash;as logic and methodmdash;is Hegelrsquo;s attempt at a philosophical comprehension of the conflicts and the deep changes of his contemporary world. This idea of dialectic as logic of historical transformation guides the development of consciousness in the emPhenomenology of Spirit/em. Since my claim is that the dialectic of consciousness and its capacity of overcoming contradiction are rooted in the historical situation of 1807, the question is raised of what would be the specific problems encountered by consciousness in our contemporary worldmdash;in 2007. What are the challenges posed by our globalized world to a phenomenology of contemporary spirit; and what is the role that contradiction and dialectic play in the understanding of our own historical present?

  17. Need of paleoclimatic reconstructions to understand natural and anthropogenic climatic hazards

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    in monsoon rainfall as her economy largely depends on rainfall. Such climatic events (floods, droughts etc.) and their effects on society were recorded right from early historic period. Such historical climatic records are mostly available in the inscriptions... of the fishes. which would in turn affect the economy of the country. Along the Indian coast line, no direct evidence is available to understand the migratory changes of fishes in the past. Quest for an additional tool to decipher such eventualities in the past...

  18. Toward a better understanding of the comparatively high prostate cancer incidence rates in Utah.

    Science.gov (United States)

    Merrill, Ray M; Hilton, Sterling C; Wiggins, Charles L; Sturgeon, Jared D

    2003-04-29

    This study assesses whether comparatively high prostate cancer incidence rates among white men in Utah represent higher rates among members of the Church of Jesus Christ of Latter-day Saints (LDS or Mormons), who comprise about 70% of the state's male population, and considers the potential influence screening has on these rates. Analyses are based on 14,693 histologically confirmed invasive prostate cancer cases among men aged 50 years and older identified through the Utah Cancer Registry between 1985 and 1999. Cancer records were linked to LDS Church membership records to determine LDS status. Poisson regression was used to derive rate ratios of LDS to nonLDS prostate cancer incidence, adjusted for age, disease stage, calendar time, and incidental detection. LDS men had a 31% (95% confidence interval, 26%-36%) higher incidence rate of prostate cancer than nonLDS men during the study period. Rates were consistently higher among LDS men over time (118% in 1985-88, 20% in 1989-92, 15% in 1993-1996, and 13% in 1997-99); age (13% in ages 50-59, 48% in ages 60-69, 28% in ages 70-79, and 16% in ages 80 and older); and stage (36% in local/regional and 17% in unstaged). An age- and stage-shift was observed for both LDS and nonLDS men, although more pronounced among LDS men. Comparatively high prostate cancer incidence rates among LDS men in Utah are explained, at least in part, by more aggressive screening among these men.

  19. 76 FR 69720 - NaturEner Rim Rock Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2011-11-09

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [ Docket No. ER12-295-000] NaturEner Rim Rock Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... NaturEner Rim Rock Wind Energy, LLC's application for market-based rate authority, with an accompanying...

  20. Understanding Social Conflicts Between Forestry and Nature Protection Sectors: Case Study Velebit Mountain

    Directory of Open Access Journals (Sweden)

    Konrad Kiš

    2010-12-01

    Full Text Available Background and Purpose: The last couple of decades brought significant changes in forest and nature protection policy worldwide. Rising environmental awareness, over-utilization of scarce natural resources and global climate change set high goals for the forest and nature protection policy makers. This paper is about a case study of relations among various stakeholders on Velebit Mountain, a coast-by mountain in Central Croatia. Velebit Mountain is both: a nature protection area and a forest exploitation site, which raises various conflicts between these two sectors and major stakeholders. Purpose of this research was to investigate the relations among various interest groups and coalition parties, their opinions, aspirations and interests and, especially, the way to resolve issues or manage conflicts. Material and Methods: This case-study research was conducted in form of interviews held with the representatives of each of the defined stakeholder groups within the target area, i.e. Velebit Mountain Nature Park. Interviews consisted of several groups of questions (introductory part, conflicts, conflict management and policy development, while stakeholder groups included "Croatian Forests ltd.", a state-owned company in charge of the management of state forests, Nature Park Velebit, National Park Paklenica, National Park "Northern Velebit", hunters' associations, private forest owners, fishermen associations, representatives of the local administration and mountaineers' associations. The questionnaire consisted of open-ended questions regarding various issues divided into these four groups. The data was analyzed by using the NVivo qualitative data analysis software. Theoretical framework used in this research was Walker and Daniels' Social Conflict Theory (1997, p.13 which describes types of conflicts, ways to address them and typical sources of occurring conflicts. Results and Conclusion: The results showed which the most salient conflict

  1. Psychological Effects of Resting in Natural Environments: Improved choice reaction time and more efficient heart rate restoration as a function of resting with a window view of nature

    OpenAIRE

    Engell, Thomas

    2013-01-01

    Research indicates that natural environments can induce restorative effects on cognitive capacity and autonomic arousal, yielding improvements in cognitive functioning and more efficient heart rate restoration. The present study investigates differences in choice reaction time (CRT) and heart rate variability (HRV) in students (N=10) resting with or without a window view of a natural environment after a minor physical exertion. Subjects performed a pre-test of a Deary-Liewald choice reaction ...

  2. On the way to understanding the time phenomenon the constructions of time in natural science

    CERN Document Server

    Time is considered as an independent entity which cannot be reduced to the concept of matter, space or field. The point of discussion is the "time flow" conception of N A Kozyrev (1908-1983), an outstanding Russian astronomer and natural scientist. In addition to a review of the experimental studies of "the active properties of time", by both Kozyrev and modern scientists, the reader will find different interpretations of Kozyrev's views and some developments of his ideas in the fields of geophysics, astrophysics, general relativity and theoretical mechanics.

  3. Social media and rating sites as tools to understanding quality of care: a scoping review.

    Science.gov (United States)

    Verhoef, Lise M; Van de Belt, Tom H; Engelen, Lucien J L P G; Schoonhoven, Lisette; Kool, Rudolf B

    2014-02-20

    Insight into the quality of health care is important for any stakeholder including patients, professionals, and governments. In light of a patient-centered approach, it is essential to assess the quality of health care from a patient's perspective, which is commonly done with surveys or focus groups. Unfortunately, these "traditional" methods have significant limitations that include social desirability bias, a time lag between experience and measurement, and difficulty reaching large groups of people. Information on social media could be of value to overcoming these limitations, since these new media are easy to use and are used by the majority of the population. Furthermore, an increasing number of people share health care experiences online or rate the quality of their health care provider on physician rating sites. The question is whether this information is relevant to determining or predicting the quality of health care. The goal of our research was to systematically analyze the relation between information shared on social media and quality of care. We performed a scoping review with the following goals: (1) to map the literature on the association between social media and quality of care, (2) to identify different mechanisms of this relationship, and (3) to determine a more detailed agenda for this relatively new research area. A recognized scoping review methodology was used. We developed a search strategy based on four themes: social media, patient experience, quality, and health care. Four online scientific databases were searched, articles were screened, and data extracted. Results related to the research question were described and categorized according to type of social media. Furthermore, national and international stakeholders were consulted throughout the study, to discuss and interpret results. Twenty-nine articles were included, of which 21 were concerned with health care rating sites. Several studies indicate a relationship between information

  4. Collaborative Project: Understanding the Chemical Processes tat Affect Growth rates of Freshly Nucleated Particles

    Energy Technology Data Exchange (ETDEWEB)

    McMurry, Peter [Univ. of Minnesota, Minneapolis, MN (United States); Smuth, James [University Corporation for Atmospheric Research, Irvine, CA (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate.

  5. Growth and Survival Rate of the Snakehead (Channa striata Larvae Fed with Different Natural Feeds

    Directory of Open Access Journals (Sweden)

    Siti Mahardika

    2017-11-01

    Full Text Available Snakehead is a kind of fresh water fish that still taken from the nature, which is the yield of it fishing are unreliable. Therefore, the aquaculture technique is needed. Critical phase of snakehead aquaculture is choosing suitable feed for larvae. Based on this problem, information about first feed suitable for larvae is very important.The aim of the research is to know about growth and survival rate of snakehead larvae with different feed. The research was done in 21 days at the Center for Research and Development of Freshwater Aquaculture Bogor. Larvae with first weight 0.4±0.07 mg and length 4.56±0.53 mm were used. Fish were feed three times daily in ad satiation. Experimental design used was completely randomized design four treatment with three replications, namely A (egg yolk chicken, B (Moina sp,, C (Artemia sp. and D (silk worm. Parameters measured were the absolute length growth, the growth of absolute weight, specific growth rate, survival rate and feed efficiency. Water quality parameters were temperature, pH, DO and conductivity. The result showed that the used of silk worm as first feed for larvae indicated the best performences. The growth of the absolute length of 13.34±1.30 mm, absolute weight of 54.52±2.93mg, specific growth rate 23.85±0.21%, survival rate 97.67±2.36% and feed efficiency 82.69±7.79%. Keywords : feed, growth, larvae, silk worm, snakehead, survival rate.

  6. Probing The Structure North China To Better Understand Its Evolution, Natural Resources, And Seismic Hazards (Invited)

    Science.gov (United States)

    Keller, G. R.; Gao, R.; Qu, G.; Li, Q.; Liu, M.

    2010-12-01

    Recently, North China has been the target of a vast array of geoscience investigations that have advanced our understanding of the region. One major effort that has targeted the area is SinoProbe, which is China's ambitious national joint earth science research project that was established to develop a comprehensive understanding of the deep interior beneath the Chinese continent via a broad range of investigations that include deep drilling and geological and geophysical studies along continental-scale transects. As one of the eight major programs within SinoProbe, SinoProbe-02 (Seismic Observations) initiated a large-scale controlled-source seismic experiment in North China under the leadership of the Chinese Academy of Geological Sciences (CAGS) of the Ministry of Land and Resources (MLR) in cooperation with the University of Oklahoma and University of Missouri-Columbia in the U. S. This experiment was conducted in December of 2009 and consisted of three coordinated seismic recording activities along a profile that extended for over 400km from near Beijing northwestward to the Mongolian border. Near Beijing, the profile began near the eastern edge of the Western Block of the North China Precambrian craton, crossed this feature to the Solonker suture zone, and ended in the Central Asian orogenic belt (CAOB). The CAOB is one of the world's most prominent sites of the formation juvenile Phanerozoic crust. In January of 2010, a different effort led by the Chinese Earthquake administration was undertaken in cooperation with the same US universities. This effort targeted the Tangshan area where a devastating earthquake killed at least 250,000 people in 1976. In this seismic experiment, an innovative 3-D survey was undertaken across a 40km x 40km region centered on the city of Tangshan by deploying Texan instruments along a web of profiles with shotpoints at their intersections. This experiment targeted the middle and upper crust. A deep seismic reflection profile was

  7. ′Tigers are Our Brothers′: Understanding Human-Nature Relations in the Mishmi Hills, Northeast India

    Directory of Open Access Journals (Sweden)

    Ambika Aiyadurai

    2016-01-01

    Full Text Available Human-nature relations are diverse, multifaceted and often contradictory, especially the relationships with animals. Mishmi people living on the Sino-India border claim tigers to be their brothers and take credit for tiger protection as they observe taboos against hunting tigers. Drawing on this notion of relatedness with tigers, local residents of the Dibang Valley question the governments' recent plans to declare the Dibang Wildlife Sanctuary into Dibang Tiger Reserve and its scientific surveys of tigers and habitat mapping. This paper highlights how Mishmi people relate to tigers and how their understanding of tigers is in contest with versions of state and science, as national property or endangered species. Using in-depth interviews and participant observations in the Dibang Valley, I provide an ethnographic analysis of how different ideas of nature are played out by different actors in Arunachal Pradesh, Northeast India. Tiger conservation projects bring these conflicting versions of nature together, creating unexpected encounters between Mishmi, state and scientists. This paper aims to contribute to the understanding of changing notions of nature in the age of globalisation and an increasingly interconnected world.

  8. Evolutionary theories of aging. 1. The need to understand the process of natural selection.

    Science.gov (United States)

    Keller, L; Genoud, M

    1999-01-01

    In a Forum article Le Bourg (1998) criticized recent tests of evolutionary theories of aging and suggested alternative explanations for the long lifespan of ant queens and the positive relationship between body size and lifespan in mammals. Moreover, he attempts to criticize evolutionary theories of aging by showing that explanations other than evolutionary theories of aging probably account for the variation in human lifespan across countries. Here we show that the arguments of Le Bourg suffer several problems. First, many of the arguments reveal a misunderstanding of the process of natural selection. Second, some of the arguments reflect a lack of knowledge of evolutionary theories of aging (e.g. pre-reproductive mortality is not predicted to influence lifespan of organisms contrary to what is claimed). Finally, his final example on lifespan in humans simply is a straw-man because serious evolutionary biologists are well aware of the importance of confounding variables and would certainly not make the type of conclusion suggested by Le Bourg. Although a critical discussion of evolutionary theories of aging is welcome, we believe that the alternative explanations proposed by Le Bourg are implausible and reflect a misunderstanding of the process of natural selection. Copyright 1999 S. Karger AG, Basel

  9. Present status of understanding on the G6PD deficiency and natural selection

    Directory of Open Access Journals (Sweden)

    Tripathy V

    2007-01-01

    Full Text Available G6PD deficiency is a common hemolytic genetic disorder, particularly in the areas endemic to malaria. Individuals are generally asymptomatic and hemolytic anemia occurs when some anti-malarial drugs or other oxidizing chemicals are administered. It has been proposed that G6PD deficiency provides protection against malaria. Maintaining of G6PD deficient alleles at polymorphic proportions is complicated because of the X-linked nature of G6PD deficiency. A comprehensive review of the literature on the hypothesis of malarial protection and the nature of the selection is being presented. Most of the epidemiological, in vitro and in vivo studies report selection for G6PD deficiency. Analysis of the G6PD gene also reveals that G6PD-deficient alleles show some signatures of selection. However, the question of how this polymorphism is being maintained remains unresolved because the selection/fitness coefficients for the different genotypes in the two sexes have not been established. Prevalence of G6PD deficiency in Indian caste and tribal populations and the different variants reported has also been reviewed.

  10. Natural Selection and Recombination Rate Variation Shape Nucleotide Polymorphism Across the Genomes of Three Related Populus Species.

    Science.gov (United States)

    Wang, Jing; Street, Nathaniel R; Scofield, Douglas G; Ingvarsson, Pär K

    2016-03-01

    A central aim of evolutionary genomics is to identify the relative roles that various evolutionary forces have played in generating and shaping genetic variation within and among species. Here we use whole-genome resequencing data to characterize and compare genome-wide patterns of nucleotide polymorphism, site frequency spectrum, and population-scaled recombination rates in three species of Populus: Populus tremula, P. tremuloides, and P. trichocarpa. We find that P. tremuloides has the highest level of genome-wide variation, skewed allele frequencies, and population-scaled recombination rates, whereas P. trichocarpa harbors the lowest. Our findings highlight multiple lines of evidence suggesting that natural selection, due to both purifying and positive selection, has widely shaped patterns of nucleotide polymorphism at linked neutral sites in all three species. Differences in effective population sizes and rates of recombination largely explain the disparate magnitudes and signatures of linked selection that we observe among species. The present work provides the first phylogenetic comparative study on a genome-wide scale in forest trees. This information will also improve our ability to understand how various evolutionary forces have interacted to influence genome evolution among related species. Copyright © 2016 by the Genetics Society of America.

  11. Nitric oxide-to-nitrogen dioxide conversion rates at a natural gas compressor station

    International Nuclear Information System (INIS)

    Gibbons, T.H.; Gebhart, D.H.

    1992-01-01

    An ambient air quality measurements program collected NO x data for a year at a natural gas compressor station located in the southwestern United States. This monitoring program had the unique characteristic of measuring ambient NO x concentrations at a remote location that was virtually free of NO sources other than the compressor station. These measurements indicate that the only source of NO x emissions in the area comes from the combustion of natural gas by the compressor station turbines. Thus, increases in NO 2 calculation of NO-to-NO 2 conversion rates. These results indicate 22 percent of the compressor station NO x emissions were converted to NO 2 in the near field. Regulatory modeling methods often assume that all NO x emissions exist as NO 2 . In an environment where ozone concentrations are relatively low, however, NO 2 concentrations are commonly calculated using the ozone limiting method (OLM), wherein NO conversion to NO 2 is limited by the amount of ozone present. Results from the measurement program show that the OLM generally overpredicts NO 2 concentrations in the near field. A partial conversion method is more suitable for predicting NO 2 concentrations for low-level natural gas combustion sources

  12. Measurement of the dry deposition rates on trees by using the natural radioactivity as a tracer

    International Nuclear Information System (INIS)

    Schreiber, H.; Jenderek, H.; Roth, C.

    1993-09-01

    Measurement of the dry deposition rates on trees by using the natural radioactivity as a tracer. The direct measurement of dry deposition fluxes into a canopy or onto single branches or leaves is difficult. The natural particle bound radioactivity in the ground-level air can be used as a tracer to gain information on this process in small scales of time and space. γ- and α-spectroscopy of radioactive daughters of Rn and Tn deposited on filters and on leaves, needles and surrogate acceptors have been developed as highly mobile field-methods. Applying Radon daughters as tracers leads to information on deposition velocities during short time intervals. The evaluation of meteorological effects in the field thus becomes possible. The main factors influencing the deposition velocity are the particle size and the wind speed. Therefore size fractionating sampling devices and anemometer arrangements are needed, both small, light-weight and cheap. We prefered filter and impactor combinations to gain 4 size fractions suitable for radioactivity and composition measurements. The concentration values of compounds and elements have been evaluated by X-ray fluorescence and ionchromatography. Numerous results of measurements on natural leaves and surrogates are presented, showing the state of developement now attained and proving the applicability of this method. (orig.). 41 figs., 108 refs., 28 tabs [de

  13. The Effects of Case-Based Instruction on Undergraduate Biology Students' Understanding of the Nature of Science

    Science.gov (United States)

    Burniston, Amy Lucinda

    Undergraduate science education is currently seeing a dramatic pedagogical push towards teaching the philosophies underpinning science as well as an increase in strategies that employ active learning. Many active learning strategies stem from constructivist ideals and have been shown to affect a student's understanding of how science operates and its impact on society- commonly referred to as the nature of science (NOS). One particular constructivist teaching strategy, case-based instruction (CBI), has been recommended by researchers and science education reformists as an effective instructional strategy for teaching NOS. Furthermore, when coupled with explicit-reflective instruction, CBI has been found to significantly increasing understanding of NOS in elementary and secondary students. However, few studies aimed their research on CBI and NOS towards higher education. Thus, this study uses a quasi-experimental, nonequivalent group design to study the effects of CBI on undergraduate science students understandings of NOS. Undergraduate biology student's understanding of NOS were assessed using the Views of Science Education (VOSE) instrument pre and post CBI intervention in Cellular and Molecular Biology and Human Anatomy and Physiology II. Data analysis indicated statistically significant differences between students NOS scores in experimental versus control sections for both courses, with experimental groups obtaining higher posttest scores. The results of this study indicate that undergraduate male and female students have similarly poor understandings of NOS and the use of historical case based instruction can be used as a means to increase undergraduate understanding of NOS.

  14. Return rates from intertidal foraging from Blombos Cave to Pinnacle Point: Understanding early human economies.

    Science.gov (United States)

    De Vynck, Jan C; Anderson, Robert; Atwater, Chloe; Cowling, Richard M; Fisher, Erich C; Marean, Curtis W; Walker, Robert S; Hill, Kim

    2016-03-01

    The south coast of South Africa provides the earliest evidence for Middle Stone Age (MSA) coastal resource exploitation by early Homo sapiens. In coastal archaeology worldwide, there has been a debate over the general productivity of intertidal foraging, leading to studies that directly measure productivity in some regions, but there have been no such studies in South Africa. Here we present energetic return rate estimates for intertidal foraging along the southern coast of South Africa from Blombos Cave to Pinnacle Point. Foraging experiments were conducted with Khoi-San descendants of the region, and hourly caloric return rates for experienced foragers were measured on 41 days near low tide and through three seasons over two study years. On-site return rates varied as a function of sex, tidal level, marine habitat type and weather conditions. The overall energetic return rate from the entire sample (1492 kcal h(-1)) equals or exceeds intertidal returns reported from other hunter-gatherer studies, as well as measured return rates for activities as diverse as hunting mammals and plant collecting. Returns are projected to be exceptionally high (∼ 3400 kcal h(-1) for men, ∼ 1900 kcal h(-1) for women) under the best combination of conditions. However, because of the monthly tidal cycle, high return foraging is only possible for about 10 days per month and for only 2-3 h on those days. These experiments suggest that while intertidal resources are attractive, women and children could not have subsisted independently, nor met all their protein-lipid needs from marine resources alone, and would have required substantial additional energy and nutrients from plant gathering and/or from males contributing game. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Methane production rates from natural organics of glacial lake clay and granitic groundwater

    International Nuclear Information System (INIS)

    Sheppard, M.I.; Stroes-Gascoyne, S.; Hawkins, J.L.; Hamon, C.J.; Motycka, M.

    1996-05-01

    Engineered barrier materials are an integral part of the proposed Canadian concept for the disposal of used nuclear fuel or high level waste. Components of these barriers, such as the buffer and backfill clays surrounding the waste containers in a vault, and granitic groundwater, naturally contain small quantities of organic material (up to about 1.2 wt%). Despite high temperatures, space and water limitations and radiation effects, the question remains whether gas could be produced from these organics as a result of biological processes. Degradation of organic carbon by microbes can produce gases such as carbon dioxide (C0 2 ) and methane (CH 4 ). This work demonstrates that methane is produced in natural systems containing 2 . In deep fracture zone groundwater, the largest methane production rate was 0.19 mole %/day or 5 μg CH 4 /L groundwater per day, at STP. This can be compared with the methane production rate of 1 μg CH 4 /(kg clay · day) at STP in an earlier experiment containing added organic material. Using this rate of 5 pg CH 4 /(L groundwater · day) (3.75 μg C/(L groundwater · day)), all of the organic C in the groundwater, assuming it is equally bioavailable, would have been converted to CH 4 during the timeframe of this experiment. Enhanced methane production occurred with an increase in natural organic carbon, an increase in the microbe population and with the addition of Fe. Steady-state methane production rates of 10 to 25 μg CH 4 / L groundwater per day have been repeatedly observed in clay-free systems. The effects of microbial metabolism, the requirement for a facilitating consortium, the Eh, the pH, the salinity, the groundwater sulphate concentration, the presence of methanotrophs and the sorption effects of clay interlayers are discussed as possible explanations for the inhibition of methanogenesis and methane production in the presence of clay and crushed granite. (author). 49 refs., 11 tabs., 12 figs

  16. Enhancing Understanding Of Coupled Human-Natural Systems Through Collaborative Learning

    Science.gov (United States)

    Santelmann, M. V.; Chan, S.; Morzillo, A.; Stebbins, A.; Wright, M.

    2012-12-01

    In the past decade, it has become clear that the dynamic nature of coupled human-natural systems must be better understood and incorporated into decision making. If the interactions between society and the rest of the ecosystem are poorly represented in system models, our ability to explore the potential consequences of feedbacks between the biophysical system and policy or management actions will be limited. Teams of researchers from three Oregon universities are collaborating with regional experts, water managers, and decision-makers to examine how climate change, population growth, and economic growth may alter the availability and use of water in the Willamette River Basin over the next one hundred years. A central project component is development of a version of the ENVISION modeling framework that will provide decision makers with a way to visualize the Willamette water system and evaluate the interaction of management choices with changing environmental and socioeconomic conditions. Key objectives of the project broader impacts team include: 1) assist with incorporating the human component of the system into the model, (2) fostering growth of the research team as an interdependent, interdisciplinary research community, and (3) communicating effectively with regional stakeholders. Through Learning-Action Networks we have been able to gather insightful, project-relevant knowledge on water use, management, policies and issues that impact water management in the region. We have identified the types of project outputs that managers and decision makers would find useful for anticipating water scarcity and informing integrative water systems responses. Events and processes used to accomplish our objectives began with field trips involving researchers, educators, and other stakeholders. Follow-up meetings and an all day symposium featured focus group interviews, plenary sessions on project progress, and interactive poster sessions in which participants could help

  17. Quantifying Urban Texture in Nairobi, Kenya and its Implications for Understanding Natural Hazard Impact

    Science.gov (United States)

    Taylor, Faith E.; Malamud, Bruce D.; Millington, James D. A.

    2016-04-01

    The configuration of infrastructure networks such as roads, drainage and power lines can both affect and be affected by natural hazards such as earthquakes, intense rain, wildfires and extreme temperatures. In this paper, we present and compare two methods to quantify urban topology on approximate scales of 0.0005 km2 to 10 km2 and create classifications of different 'urban textures' that relate to risk of natural hazard impact in an area. The methods we use focus on applicability in urban developing country settings, where access to high resolution and high quality data may be difficult. We use the city of Nairobi, Kenya to trial these methods. Nairobi has a population >3 million, and is a mix of informal settlements, residential and commercial development. The city and its immediate surroundings are subject to a variety of natural hazards such as floods, landslides, fires, drought, hail, heavy wind and extreme temperatures; all of these hazards can occur singly, but also have the potential for one to trigger another, thus providing a 'cascade' of hazards, or for two of the hazards to occur spatially and temporally near each other and interact. We use two measures of urban texture: (i) Street block textures, (ii) Google Earth land cover textures. Street block textures builds on the methodology of Louf and Barthelemy (2014) and uses Open Street Map data to analyse the shape, size, complexity and pattern of individual blocks of land created by fully enclosed loops of the major and minor road network of Nairobi. We find >4000 of these blocks ranging in size from approximately 0.0005 km2 to 10 km2, with approximately 5 classifications of urban texture. Google Earth land cover texture is a visual classification of homogeneous parcels of land performed in Google Earth using high-resolution airborne imagery and a qualitative criteria for each land cover type. Using the Google Earth land cover texture method, we identify >40 'urban textures' based on visual

  18. Using Scaling to Understand, Model and Predict Global Scale Anthropogenic and Natural Climate Change

    Science.gov (United States)

    Lovejoy, S.; del Rio Amador, L.

    2014-12-01

    The atmosphere is variable over twenty orders of magnitude in time (≈10-3 to 1017 s) and almost all of the variance is in the spectral "background" which we show can be divided into five scaling regimes: weather, macroweather, climate, macroclimate and megaclimate. We illustrate this with instrumental and paleo data. Based the signs of the fluctuation exponent H, we argue that while the weather is "what you get" (H>0: fluctuations increasing with scale), that it is macroweather (Hbackground as close to white noise and focuses on quasi-periodic variability assumes a spectrum that is in error by a factor of a quadrillion (≈ 1015). Using this scaling framework, we can quantify the natural variability, distinguish it from anthropogenic variability, test various statistical hypotheses and make stochastic climate forecasts. For example, we estimate the probability that the warming is simply a giant century long natural fluctuation is less than 1%, most likely less than 0.1% and estimate return periods for natural warming events of different strengths and durations, including the slow down ("pause") in the warming since 1998. The return period for the pause was found to be 20-50 years i.e. not very unusual; however it immediately follows a 6 year "pre-pause" warming event of almost the same magnitude with a similar return period (30 - 40 years). To improve on these unconditional estimates, we can use scaling models to exploit the long range memory of the climate process to make accurate stochastic forecasts of the climate including the pause. We illustrate stochastic forecasts on monthly and annual scale series of global and northern hemisphere surface temperatures. We obtain forecast skill nearly as high as the theoretical (scaling) predictability limits allow: for example, using hindcasts we find that at 10 year forecast horizons we can still explain ≈ 15% of the anomaly variance. These scaling hindcasts have comparable - or smaller - RMS errors than existing GCM

  19. Munazza's story: Understanding science teaching and conceptions of the nature of science in Pakistan through a life history study

    Science.gov (United States)

    Halai, Nelofer

    In this study I have described and tried to comprehend how a female science teacher understands her practice. Additionally, I have developed some understanding of her understanding of the nature of science. While teaching science, a teacher projects messages about the nature of science that can be captured by observations and interviews. Furthermore, the manner is which a teacher conceptualizes science for teaching, at least in part, depends on personal life experiences. Hence, I have used the life history method to understand Munazza's practice. Munazza is a young female science teacher working in a private, co-educational school for children from middle income families in Karachi, Pakistan. Her stories are central to the study, and I have represented them using a number of narrative devices. I have woven in my own stories too, to illustrate my perspective as a researcher. The data includes 13 life history interviews and many informal conversations with Munazza, observations of science teaching in classes seven and eight, and interviews with other science teachers and administrative staff of the school. Munazza's personal biography and experiences of school and undergraduate courses has influenced the way she teaches. It has also influenced the way she does not teach. She was not inspired by her science teachers, so she has tried not to teach the way she was taught science. Contextual factors, her conception of preparation for teaching as preparation for subject content and the tension that she faces in balancing care and control in her classroom are some factors that influence her teaching. Munazza believes that science is a stable, superior and value-free way of knowing. In trying to understand the natural world, observations come first, which give reliable information about the world leading inductively to a "theory". Hence, she relies a great deal on demonstrations in the class where students "see" for themselves and abstract the scientific concept from the

  20. Understanding the physiology of mindfulness: aortic hemodynamics and heart rate variability.

    Science.gov (United States)

    May, Ross W; Bamber, Mandy; Seibert, Gregory S; Sanchez-Gonzalez, Marcos A; Leonard, Joseph T; Salsbury, Rebecca A; Fincham, Frank D

    2016-01-01

    Data were collected to examine autonomic and hemodynamic cardiovascular modulation underlying mindfulness from two independent samples. An initial sample (N = 185) underwent laboratory assessments of central aortic blood pressure and myocardial functioning to investigated the association between mindfulness and cardiac functioning. Controlling for religiosity, mindfulness demonstrated a strong negative relationship with myocardial oxygen consumption and left ventricular work but not heart rate or blood pressure. A second sample (N = 124) underwent a brief (15 min) mindfulness inducing intervention to examine the influence of mindfulness on cardiovascular autonomic modulation via blood pressure variability and heart rate variability. The intervention had a strong positive effect on cardiovascular modulation by decreasing cardiac sympathovagal tone, vasomotor tone, vascular resistance and ventricular workload. This research establishes a link between mindfulness and cardiovascular functioning via correlational and experimental methodologies in samples of mostly female undergraduates. Future directions for research are outlined.

  1. Final Report: "Collaborative Project. Understanding the Chemical Processes That Affect Growth Rates of Freshly Nucleated Particles"

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James N. [NCAR, Boulder, CO (United States); McMurry, Peter H. [NCAR, Boulder, CO (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate. Our measurements include a self-organized, DOE-ARM funded project at the Southern Great Plains site, the New Particle Formation Study (NPFS), which took place during spring 2013. NPFS data are available to the research community on the ARM data archive, providing a unique suite observations of trace gas and aerosols that are associated with the formation and growth of atmospheric aerosol particles.

  2. Influence of natural thermal gradients on whole animal rates of protein synthesis in marine gammarid amphipods.

    Directory of Open Access Journals (Sweden)

    Samuel P S Rastrick

    Full Text Available Although temperature is known to have an important effect on protein synthesis rates and growth in aquatic ectotherms held in the laboratory, little is known about the effects of thermal gradients on natural populations in the field. To address this issue we determined whole-animal fractional rates of protein synthesis (ks in four dominant species of gammarid amphipods with different distributions along the coasts of Western Europe from arctic to temperate latitudes. Up to three populations of each species were collected in the summer and ks measured within 48 h. Summer ks values were relatively high in the temperate species, Gammarus locusta, from Portugal (48°N and Wales (53°N and were maintained across latitudes by the conservation of translational efficiency. In sharp contrast, summer ks remained remarkably low in the boreal/temperate species G. duebeni from Wales, Scotland (58°N and Tromsø (70°N, probably as a temporary energy saving strategy to ensure survival in rapidly fluctuating environments of the high intertidal. Values for ks increased in acclimated G. duebeni from Scotland and Tromsø showing a lack of compensation with latitude. In the subarctic/boreal species, G. oceanicus, summer ks remained unchanged in Scotland and Tromsø but fell significantly in Svalbard (79°N at 5°C, despite a slight increase in RNA content. At 79°N, mean ks was 4.5 times higher in the circumpolar species G. setosus than in G. oceanicus due to a doubling in RNA content. The relationship between whole-animal protein synthesis rates and natural thermal gradients is complex, varies between species and appears to be associated with local temperatures and their variability, as well as changes in other environmental factors.

  3. Natural Firing Patterns Imply Low Sensitivity of Synaptic Plasticity to Spike Timing Compared with Firing Rate.

    Science.gov (United States)

    Graupner, Michael; Wallisch, Pascal; Ostojic, Srdjan

    2016-11-02

    Synaptic plasticity is sensitive to the rate and the timing of presynaptic and postsynaptic action potentials. In experimental protocols inducing plasticity, the imposed spike trains are typically regular and the relative timing between every presynaptic and postsynaptic spike is fixed. This is at odds with firing patterns observed in the cortex of intact animals, where cells fire irregularly and the timing between presynaptic and postsynaptic spikes varies. To investigate synaptic changes elicited by in vivo-like firing, we used numerical simulations and mathematical analysis of synaptic plasticity models. We found that the influence of spike timing on plasticity is weaker than expected from regular stimulation protocols. Moreover, when neurons fire irregularly, synaptic changes induced by precise spike timing can be equivalently induced by a modest firing rate variation. Our findings bridge the gap between existing results on synaptic plasticity and plasticity occurring in vivo, and challenge the dominant role of spike timing in plasticity. Synaptic plasticity, the change in efficacy of connections between neurons, is thought to underlie learning and memory. The dominant paradigm posits that the precise timing of neural action potentials (APs) is central for plasticity induction. This concept is based on experiments using highly regular and stereotyped patterns of APs, in stark contrast with natural neuronal activity. Using synaptic plasticity models, we investigated how irregular, in vivo-like activity shapes synaptic plasticity. We found that synaptic changes induced by precise timing of APs are much weaker than suggested by regular stimulation protocols, and can be equivalently induced by modest variations of the AP rate alone. Our results call into question the dominant role of precise AP timing for plasticity in natural conditions. Copyright © 2016 Graupner et al.

  4. Understanding resident ratings of teaching in the workplace: a multi-centre study.

    Science.gov (United States)

    Fluit, Cornelia R M G; Feskens, Remco; Bolhuis, Sanneke; Grol, Richard; Wensing, Michel; Laan, Roland

    2015-08-01

    Providing clinical teachers with feedback about their teaching skills is a powerful tool to improve teaching. Evaluations are mostly based on questionnaires completed by residents. We investigated to what extent characteristics of residents, clinical teachers, and the clinical environment influenced these evaluations, and the relation between residents' scores and their teachers' self-scores. The evaluation and feedback for effective clinical teaching questionnaire (EFFECT) was used to (self)assess clinical teachers from 12 disciplines (15 departments, four hospitals). Items were scored on a five-point Likert scale. Main outcome measures were residents' mean overall scores (MOSs), specific scale scores (MSSs), and clinical teachers' self-evaluation scores. Multilevel regression analysis was used to identify predictors. Residents' scores and self-evaluations were compared. Residents filled in 1,013 questionnaires, evaluating 230 clinical teachers. We received 160 self-evaluations. 'Planning Teaching' and 'Personal Support' (4.52, SD .61 and 4.53, SD .59) were rated highest, 'Feedback Content' (CanMEDS related) (4.12, SD .71) was rated lowest. Teachers in affiliated hospitals showed highest MOS and MSS. Medical specialty did not influence MOS. Female clinical teachers were rated higher for most MSS, achieving statistical significance. Residents in year 1-2 were most positive about their teachers. Residents' gender did not affect the mean scores, except for role modeling. At group level, self-evaluations and residents' ratings correlated highly (Kendall's τ 0.859). Resident evaluations of clinical teachers are influenced by teacher's gender, year of residency training, type of hospital, and to a lesser extent teachers' gender. Clinical teachers and residents agree on strong and weak points of clinical teaching.

  5. Understanding Rates of Marijuana Use and Consequences Among Adolescents in a Changing Legal Landscape

    OpenAIRE

    D’Amico, Elizabeth J.; Tucker, Joan S.; Pedersen, Eric R.; Shih, Regina A.

    2017-01-01

    Purpose of Review There is not one answer to address whether marijuana use has increased, decreased, or stayed the same given changes in state legalization of medical and non-medical marijuana in the USA. Recent Findings Evidence suggests some health benefits for medical marijuana; however, initiation of marijuana use is a risk factor for developing problem cannabis use. Though use rates have remained stable over recent years, about one in three 10th graders report marijuana use, most adolesc...

  6. Understanding to Hierarchical Microstructures of Crab (Chinese hairy) Shell as a Natural Architecture

    International Nuclear Information System (INIS)

    Chuanqiang, Zhou; Xiangxiang, Gong; Jie, Han

    2016-01-01

    This work was done to better understand the microstructures, composition and mechanical properties of Chinese hairy crab shell. For fully revealing its hierarchical microstructure, the crab shell was observed with electron microscope under different magnifications from different facets. XRD, EDS, FTIR and TGA techniques have been used to characterize the untreated and chemically-treated crab shells, which provided enough information to determine the species and relative content of components in this biomaterial. Combined the microstructures with constituents analysis, the structural principles of crab shell was detailedly realized from different structural levels beyond former reports. To explore the relationship between structure and function, the mechanical properties of shell have been measured through performing tensile tests. The contributions of organics and minerals in shell to the mechanical properties were also discussed by measuring the tensile strength of de-calcification samples treated with HCl solution

  7. Understanding to Hierarchical Microstructures of Crab (Chinese hairy) Shell as a Natural Architecture

    Energy Technology Data Exchange (ETDEWEB)

    Chuanqiang, Zhou [Testing Center, Yangzhou University, No. 48 Wenhui East Road, Yangzhou (China); Xiangxiang, Gong [Testing Center, Yangzhou University, No. 48 Wenhui East Road, Yangzhou (China); School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou (China); Jie, Han [School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou (China)

    2016-03-07

    This work was done to better understand the microstructures, composition and mechanical properties of Chinese hairy crab shell. For fully revealing its hierarchical microstructure, the crab shell was observed with electron microscope under different magnifications from different facets. XRD, EDS, FTIR and TGA techniques have been used to characterize the untreated and chemically-treated crab shells, which provided enough information to determine the species and relative content of components in this biomaterial. Combined the microstructures with constituents analysis, the structural principles of crab shell was detailedly realized from different structural levels beyond former reports. To explore the relationship between structure and function, the mechanical properties of shell have been measured through performing tensile tests. The contributions of organics and minerals in shell to the mechanical properties were also discussed by measuring the tensile strength of de-calcification samples treated with HCl solution.

  8. Understanding High Recession Rates of Carbon Ablators Seen in Shear Tests in an Arc Jet

    Science.gov (United States)

    Driver, David M.; Olson, Michael W.; Barnhardt, Michael D.; MacLean, Matthew

    2010-01-01

    High rates of recession in arc jet shear tests of Phenolic Impregnated Carbon Ablator (PICA) inspired a series of tests and analysis on FiberForm (a carbon preform used in the fabrication of PICA). Arc jet tests were performed on FiberForm in both air and pure nitrogen for stagnation and shear configurations. The nitrogen tests showed little or no recession, while the air tests of FiberForm showed recession rates similar to that of PICA (when adjusted for the difference in density). While mechanical erosion can not be ruled out, this is the first step in doing so. Analysis using a carbon oxidation boundary condition within DPLR was used to predict the recession rate of FiberForm. The analysis indicates that much of the anomalous recession behavior seen in shear tests may simply be an artifact of the non-flight like test configuration (copper upstream of the test article) a result of dissimilar enthalpy and oxygen concentration profiles on the copper. Shape change effects were also investigated and shown to be relatively small.

  9. Biological Principles and Threshold Concepts for Understanding Natural Selection. Implications for Developing Visualizations as a Pedagogic Tool

    Science.gov (United States)

    Tibell, Lena A. E.; Harms, Ute

    2017-11-01

    Modern evolutionary theory is both a central theory and an integrative framework of the life sciences. This is reflected in the common references to evolution in modern science education curricula and contexts. In fact, evolution is a core idea that is supposed to support biology learning by facilitating the organization of relevant knowledge. In addition, evolution can function as a pivotal link between concepts and highlight similarities in the complexity of biological concepts. However, empirical studies in many countries have for decades identified deficiencies in students' scientific understanding of evolution mainly focusing on natural selection. Clearly, there are major obstacles to learning natural selection, and we argue that to overcome them, it is essential to address explicitly the general abstract concepts that underlie the biological processes, e.g., randomness or probability. Hence, we propose a two-dimensional framework for analyzing and structuring teaching of natural selection. The first—purely biological—dimension embraces the three main principles variation, heredity, and selection structured in nine key concepts that form the core idea of natural selection. The second dimension encompasses four so-called thresholds, i.e., general abstract and/or non-perceptual concepts: randomness, probability, spatial scales, and temporal scales. We claim that both of these dimensions must be continuously considered, in tandem, when teaching evolution in order to allow development of a meaningful understanding of the process. Further, we suggest that making the thresholds tangible with the aid of appropriate kinds of visualizations will facilitate grasping of the threshold concepts, and thus, help learners to overcome the difficulties in understanding the central theory of life.

  10. Bank voles show high seropositivity rates in a natural TBEV focus in Hungary.

    Science.gov (United States)

    Zöldi, Viktor; Papp, Tibor; Reiczigel, Jenő; Egyed, László

    2015-03-01

    Rodents captured in a known tick-borne encephalitis virus (TBEV) focus were serologically surveyed for 4 years, with 28 visits. The collected sera were analysed by virus neutralization test. Bank vole (Myodes glareolus) had a significantly higher incidence rate of antibodies to TBEV (20.5%) than Apodemus flavicollis (3.7%) and Apodemus agrarius (4.6%). In all species, rates were higher in adults (6.8%) than in juveniles (1.7%). A higher incidence rate was observed in female A. flavicollis individuals (6.7%) than in males (1.5%). Smaller bank vole population coincided with lower (1.2-4.8%) seropositivity in all small rodents, while more abundant bank vole population meant higher (17.9%) total seropositivity. The TBEV focus originally had only Apodemus mice, bank voles appeared later, reached 20.5% positivity and raised the positivity in small rodents from 4% to 10.2% in 3 years. The results highlight the role of M. glareolus and of adult rodents in maintaining the TBEV in nature.

  11. Understanding the coupled natural and human systems in Dryland East Asia

    International Nuclear Information System (INIS)

    Qi Jiaguo; Chen Jiquan; Wan Shiqian; Ai Likun

    2012-01-01

    Stressors including regional climate change, economic development effects upon land use and an increasing demand for food production have resulted in significant impacts on the dryland ecosystems in the East Asia (DEA) region. Ecosystem services, such as its provisional services in providing forage for grazing as well as its functional services in regulating water and carbon fluxes, have been significantly altered over the past three decades. Conversely, changes in the landscape, particularly land cover types, have also been blamed for intensified climatic events such as dust storms and severe and frequent droughts within the region. The interactive nature of climate, ecosystems and society is complex and not fully understood, making it difficult, if not impossible, to develop effective adaptation strategies for the region. A special synthesis workshop on ‘Dryland Ecosystems in East Asia: State, Changes, Knowledge Gaps, and Future’ was held from 18–20 July 2011 in Kaifeng, Henan Province, China, with the aim of identifying knowledge gaps, quantifying impacts and developing a future research agenda for the region. The specific objectives of this workshop were to answer some key socio-environmental questions, including the following. (1) What do we know about the drylands in DEA? (2) What are the knowledge gaps? (3) What are the solutions to these issues? This paper provides a synthesis of the workshop consensus and findings on the state of knowledge and challenges in addressing these science issues for the DEA region. (letter)

  12. Understanding fluid transport through the multiscale pore network of a natural shale

    Directory of Open Access Journals (Sweden)

    Davy Catherine A.

    2017-01-01

    Full Text Available The pore structure of a natural shale is obtained by three imaging means. Micro-tomography results are extended to provide the spatial arrangement of the minerals and pores present at a voxel size of 700 nm (the macroscopic scale. FIB/SEM provides a 3D representation of the porous clay matrix on the so-called mesoscopic scale (10-20 nm; a connected pore network, devoid of cracks, is obtained for two samples out of five, while the pore network is connected through cracks for two other samples out of five. Transmission Electron Microscopy (TEM is used to visualize the pore space with a typical pixel size of less than 1 nm and a porosity ranging from 0.12 to 0.25. On this scale, in the absence of 3D images, the pore structure is reconstructed by using a classical technique, which is based on truncated Gaussian fields. Permeability calculations are performed with the Lattice Boltzmann Method on the nanoscale, on the mesoscale, and on the combination of the two. Upscaling is finally done (by a finite volume approach on the bigger macroscopic scale. Calculations show that, in the absence of cracks, the contribution of the nanoscale pore structure on the overall permeability is similar to that of the mesoscale. Complementarily, the macroscopic permeability is measured on a centimetric sample with a neutral fluid (ethanol. The upscaled permeability on the macroscopic scale is in good agreement with the experimental results.

  13. Understanding Public Support for Indigenous Natural Resource Management in Northern Australia

    Directory of Open Access Journals (Sweden)

    Kerstin K. Zander

    2013-03-01

    Full Text Available Increased interest in indigenous-led natural resource management (NRM on traditionally owned land in northern Australia has raised important questions in relation to policies that compensate indigenous Australians for providing environmental services. A choice experiment survey was mailed out to respondents across the whole of Australia to assess if and to what extent Australian people think that society benefits from these services and how much they would pay for them. More than half the respondents would in principle support indigenous NRM in northern Australia, with a high willingness to pay for carbon, biodiversity, and recreational services. Social aspects of indigenous NRM, however, were not valued by the society, emphasizing the need for awareness raising and clarifications of benefits that indigenous people gain while carrying out land management on their traditional country. Any marketing campaign should take into account preference variation across Australian society, which this research shows is substantial, particularly between people from the north and those from the south. People from the south were more likely to support indigenous NRM, a significant finding for campaigns targeting potential donors.

  14. Queueing theoretic analysis of labor and delivery : Understanding management styles and C-section rates.

    Science.gov (United States)

    Gombolay, Matthew; Golen, Toni; Shah, Neel; Shah, Julie

    2017-09-04

    Childbirth is a complex clinical service requiring the coordinated support of highly trained healthcare professionals as well as management of a finite set of critical resources (such as staff and beds) to provide safe care. The mode of delivery (vaginal delivery or cesarean section) has a significant effect on labor and delivery resource needs. Further, resource management decisions may impact the amount of time a physician or nurse is able to spend with any given patient. In this work, we employ queueing theory to model one year of transactional patient information at a tertiary care center in Boston, Massachusetts. First, we observe that the M/G/∞ model effectively predicts patient flow in an obstetrics department. This model captures the dynamics of labor and delivery where patients arrive randomly during the day, the duration of their stay is based on their individual acuity, and their labor progresses at some rate irrespective of whether they are given a bed. Second, using our queueing theoretic model, we show that reducing the rate of cesarean section - a current quality improvement goal in American obstetrics - may have important consequences with regard to the resource needs of a hospital. We also estimate the potential financial impact of these resource needs from the hospital perspective. Third, we report that application of our model to an analysis of potential patient coverage strategies supports the adoption of team-based care, in which attending physicians share responsibilities for patients.

  15. Considering Hans-Georg Gadamer's philosophical hermeneutics as a referent for student understanding of nature-of-science concepts

    Science.gov (United States)

    Rashford, Jared M.

    The purpose of this study is to examine philosophical hermeneutics as a referent for student understanding of Nature-of-Science (NOS) concepts. Rather than focus on a prescriptive set of canons used in addressing NOS pedagogy in K-12 schools, this study seeks to explicate a descriptive set of principles based on Hans-Georg Gadamer's theory of interpretation that has the potential for developing dispositions necessary for understanding. Central among these are the concepts of fore-structure, prejudice, temporal distance, and history of effect, all of which constitute part of the whole of the hermeneutic circle as envisaged by Gadamer. As such, Gadamer's hermeneutics is contrasted with Cartesian epistemology and its primacy of method, the Enlightenment's prejudice against prejudice, the modernist/progressive tendency to consider all situations as problems to be solved by relegating all forms of knowledge to techne, and the subjective nature of interpretation inherent in a hermeneutics of suspicion. The implication of such a conceptual analysis for NOS pedagogy is that student understanding is considered not so much as a cognitive outcome dependent on a series of mental functions but rather as an ontological characteristic of Dasein (being-human) that situates learning in the interchange between interpreter and text. In addition, the philosophical foundations implicit in addressing student understanding of NOS found in many curricular reform efforts and pedagogical practices in science education are questioned. Gadamer's hermeneutics affords science education a viable philosophical framework within which to consider student understanding of the development of scientific knowledge and the scientific enterprise.

  16. Dynamic Compressive Strength and Failure of Natural Lake Ice Under Moderate Strain Rates at Near Melting Point Temperature

    Directory of Open Access Journals (Sweden)

    Chunfeng Qi

    Full Text Available Abstract This paper presents a series of uniaxial compressive experiments on natural lake ice under moderate strain-rate in the range of 10−1 to 102 s−1 at −0.1 °C. Natural lake ice samples of 8 cm by 8 cm in cross section and 20 cm high were used to investigate strain-rate dependence of uniaxial compressive strength and flaw effects on ice strength under moderate strain rates. The fracture modes of ice at moderate strain rates were also systematically investigated by using high-speed camera. It is found uniaxial compressive strength of natural lake ice increases with increasing strain-rate in the employed moderate strain-rate range. And natural flaws such as air bubble have a significant effect on uniaxial compressive strength of ice under moderate strain-rate, higher air content ice possesses lower compressive strength. Ice fracture mode depends on strain-rate (or compressive velocity of ice specimen, varying from splitting at strain rates lower than 10 s−1 to crushing at strain rates higher than 10 s−1. Ice specimen crushes into fine fragments may due to insufficient time for micro cracks to propagate, thus results in higher strength. In addition, dependence of compressive strength on strain-rate in a wide strain-rate range is also discussed.

  17. Neurobiological approaches to a better understanding of human nature and human values

    Directory of Open Access Journals (Sweden)

    Gerald Hüther

    2006-04-01

    of values of connectedness to others and to nature during the period of brain maturation.

  18. Recognition of time-compressed speech does not predict recognition of natural fast-rate speech by older listeners.

    Science.gov (United States)

    Gordon-Salant, Sandra; Zion, Danielle J; Espy-Wilson, Carol

    2014-10-01

    This study investigated whether recognition of time-compressed speech predicts recognition of natural fast-rate speech, and whether this relationship is influenced by listener age. High and low context sentences were presented to younger and older normal-hearing adults at a normal speech rate, naturally fast speech rate, and fast rate implemented by time compressing the normal-rate sentences. Recognition of time-compressed sentences over-estimated recognition of natural fast sentences for both groups, especially for older listeners. The findings suggest that older listeners are at a much greater disadvantage when listening to natural fast speech than would be predicted by recognition performance for time-compressed speech.

  19. Determination of dose rate from natural radionuclide in porcelain dental materials

    International Nuclear Information System (INIS)

    Nouri, A.D.; El-Zourgany, A.; Elmashat, Alia; El-Masri, Karima

    2010-01-01

    There are three main aims that make this study particularly important and interesting to radiometric studies. Firstly, it will provides information on the concentration composition of natural and the associated man-made radioactivity of imported dental porcelain materials to be used by most dental laboratories in Great Jamahiriya. Since these materials do not pass radiation inspection tests before their entry or use and there is a large variety of supply source of these dental materials to be used for all dental works on Libyan patients, anomalies can be identified easily. Secondly, the analysis of selective elemental abundance (U, Th, and K ) and dose rate calculations may be used to calculate effective dose rates to dental laboratory technicians and also to the patient who will be using these specific materials. This research project will provide the first results of such measurements and the corresponding average annual effective dose rates equivalent to the patients using these materials and also to the dental technician and doctors work in the various dental laboratories that make use of these materials in their daily work. A total number of 30 dental powder samples were collected from a number of dental laboratories around Tripoli area will be analyzed. In this research project, the results from this preliminary survey regarding Th, U and K elemental concentrations in a wide variety of dental materials by means of high-resolution X-ray spectrometry will be presented. Further results from these investigations concerning activity concentrations and the associated dose rates, effective dose and the committed dose due to the use of these materials are going to be calculated and compared with other published data elsewhere and recommendation of their use will be derived accordingly. (author)

  20. Optimization of graffiti removal on natural stone by means of high repetition rate UV laser

    Energy Technology Data Exchange (ETDEWEB)

    Fiorucci, M.P., E-mail: m.p.fiorucci@udc.es [Centro de Investigacións Tecnolóxicas, Universidade da Coruña, 15403 Ferrol (Spain); Dpto. Enxeñaría dos Recursos Naturais e Medio Ambiente, E.T.S.E. Minas, Universidade de Vigo, 36200 Vigo (Spain); López, A.J., E-mail: ana.xesus.lopez@udc.es [Centro de Investigacións Tecnolóxicas, Universidade da Coruña, 15403 Ferrol (Spain); Ramil, A., E-mail: alberto.ramil@udc.es [Centro de Investigacións Tecnolóxicas, Universidade da Coruña, 15403 Ferrol (Spain); Pozo, S., E-mail: ipozo@uvigo.es [Dpto. Enxeñaría dos Recursos Naturais e Medio Ambiente, E.T.S.E. Minas, Universidade de Vigo, 36200 Vigo (Spain); Rivas, T., E-mail: trivas@uvigo.es [Dpto. Enxeñaría dos Recursos Naturais e Medio Ambiente, E.T.S.E. Minas, Universidade de Vigo, 36200 Vigo (Spain)

    2013-08-01

    The use of laser for graffiti removal is a promising alternative to conventional cleaning methods, though irradiation parameters must be carefully selected in order to achieve the effective cleaning without damaging the substrate, especially when referring to natural stone. From a practical point of view, once a safe working window is selected, it is necessary to determine the irradiation conditions to remove large paint areas, with minimal time consumption. The aim of this paper is to present a systematic procedure to select the optimum parameters for graffiti removal by means of the 3rd harmonic of a high repetition rate nanosecond Nd:YVO{sub 4} laser. Ablation thresholds of four spray paint colors were determined and the effect of pulse repetition frequency, beam diameter and line scan separation was analyzed, obtaining a set of values which optimize the ablation process.

  1. Trends in rates of natural conceptions among Danish women born during 1960-1984

    DEFF Research Database (Denmark)

    Lassen, Tina Harmer; Sobotka, Tomás; Jensen, Tina Kold

    2012-01-01

    STUDY QUESTION: The aim of the study was to analyse trends in the rate of natural conceptions (RNC) among birth cohorts of women born during the period 1960-1984. SUMMARY ANSWER: In this nationwide study of Danish-born female cohorts born during the period 1960-1984, we found a gradual decline...... in the RNC with successive birth cohorts. WHAT IS KNOWN ALREADY: Our results confirm the findings from a previous study on trends in RNC among native Danish women. STUDY DESIGN, SIZE, DURATION: This is a register-based cohort study. Our data set included 803 435 native Danish women born in 1960-1984, of whom...... the data for the cohorts of native Danish women born in 1960-1984 and resident in Denmark in 2008. For these cohorts, we estimated the RNC per woman, defined as the mean number of live births minus live births after assisted reproductive technology (ART) plus the mean number of induced abortions. Births...

  2. Optimization of graffiti removal on natural stone by means of high repetition rate UV laser

    Science.gov (United States)

    Fiorucci, M. P.; López, A. J.; Ramil, A.; Pozo, S.; Rivas, T.

    2013-08-01

    The use of laser for graffiti removal is a promising alternative to conventional cleaning methods, though irradiation parameters must be carefully selected in order to achieve the effective cleaning without damaging the substrate, especially when referring to natural stone. From a practical point of view, once a safe working window is selected, it is necessary to determine the irradiation conditions to remove large paint areas, with minimal time consumption. The aim of this paper is to present a systematic procedure to select the optimum parameters for graffiti removal by means of the 3rd harmonic of a high repetition rate nanosecond Nd:YVO4 laser. Ablation thresholds of four spray paint colors were determined and the effect of pulse repetition frequency, beam diameter and line scan separation was analyzed, obtaining a set of values which optimize the ablation process.

  3. Understanding Rates of Marijuana Use and Consequences Among Adolescents in a Changing Legal Landscape.

    Science.gov (United States)

    D'Amico, Elizabeth J; Tucker, Joan S; Pedersen, Eric R; Shih, Regina A

    2017-01-01

    There is not one answer to address whether marijuana use has increased, decreased, or stayed the same given changes in state legalization of medical and non-medical marijuana in the USA. Evidence suggests some health benefits for medical marijuana; however, initiation of marijuana use is a risk factor for developing problem cannabis use. Though use rates have remained stable over recent years, about one in three 10th graders report marijuana use, most adolescents do not view the drug as harmful, and over 650,000 youth aged 12 to 17 struggle with cannabis use disorder. Although the health benefits of medical marijuana are becoming better understood, more research is needed. Intervention and prevention programs must better address effects of marijuana, acknowledging that while there may be some benefits medically, marijuana use can affect functioning during adolescence when the brain is still developing.

  4. Understanding Response Rates to Surveys About Family Members' Psychological Symptoms After Patients' Critical Illness.

    Science.gov (United States)

    Long, Ann C; Downey, Lois; Engelberg, Ruth A; Nielsen, Elizabeth; Ciechanowski, Paul; Curtis, J Randall

    2017-07-01

    Achieving adequate response rates from family members of critically ill patients can be challenging, especially when assessing psychological symptoms. To identify factors associated with completion of surveys about psychological symptoms among family members of critically ill patients. Using data from a randomized trial of an intervention to improve communication between clinicians and families of critically ill patients, we examined patient-level and family-level predictors of the return of usable surveys at baseline, three months, and six months (n = 181, 171, and 155, respectively). Family-level predictors included baseline symptoms of psychological distress, decisional independence preference, and attachment style. We hypothesized that family with fewer symptoms of psychological distress, a preference for less decisional independence, and secure attachment style would be more likely to return questionnaires. We identified several predictors of the return of usable questionnaires. Better self-assessed family member health status was associated with a higher likelihood and stronger agreement with a support-seeking attachment style with a lower likelihood, of obtaining usable baseline surveys. At three months, family-level predictors of return of usable surveys included having usable baseline surveys, status as the patient's legal next of kin, and stronger agreement with a secure attachment style. The only predictor of receipt of surveys at six months was the presence of usable surveys at three months. We identified several predictors of the receipt of surveys assessing psychological symptoms in family of critically ill patients, including family member health status and attachment style. Using these characteristics to inform follow-up mailings and reminders may enhance response rates. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  5. The application of "natural" growth rates of Heterostegina depressa to infer timing of reproduction events

    Science.gov (United States)

    Eder, Wolfgang; Julia, Woeger; Kinoshita, Shunichi; Hohenegger, Johann; Briguglio, Antonino

    2017-04-01

    To explore applicability of the natural laboratory approach (sensu Hohenegger) on population dynamic studies of recent larger benthic foraminifera, this relatively new experimental method has been applied on Heterostegina depressa populations from Sesoko Jima, NW Okinawa, Japan. It is used to gain an averaged chamber and diameter building rate, as well as the average longevity of H. depressa based on monthly samplings at fixed sampling stations. Samples were collected by SCUBA in 16 monthly intervals around 20 and 50 meters water depth, wherefrom live populations were dried and investigated by microCT. The specimens were measured regarding chamber number and maximum diameter. This biometric data has been tested for the presence of multiple generations of H. depressa megalospheres. In case of skewed or bimodal frequency distributions, they were decomposed into normally distributed components. Means and standard deviations of each component of every month were extracted and could be used to calculate the maximum values of chamber number and diameter for all sampling intervals. Based on these maximal values, the natural chamber/diameter growth rate was fitted by Michaelis-Menten functions. By inversion of this growth functions the birthdate of every specimen was calculated. Frequency diagrams of these dates reveal a continuous background reproduction throughout the year, yet show distinct reproduction peaks in late spring and late autumn. Further, sinusoidal regression analysis support these two main reproduction cycles, one short-term cycle 70 days and a one long-term cycles around 180 days. Surprisingly, similar cycles have been found in different studies on volumetric growth of larger benthic foraminifera.

  6. Understanding sexual activity and Chlamydia testing rate based on linked national survey and Medicaid claims data.

    Directory of Open Access Journals (Sweden)

    Guoyu Tao

    Full Text Available Monitoring adherence to national recommendations for annual chlamydia screening of female adolescents and young adult women is important for targeting quality improvement interventions to improve low screening rates. However, accurate measurement of rates may vary depending on the data source used to determine eligible sexually-active women.The 2001-2004 NHANES data linked with Medicaid administrative data by respondent's unique identifier, the 2011-2012 NHANES data, and the 2004 and 2010 Medicaid data were used in this cross-sectional analysis. We defined self-reported sexual activity by self-reported sexual behaviors, claim-identified sexual activity by reproductive-related claims among women who had ≥ one healthcare claim, HEDIS-defined sexual activity by reproductive-related claims among women who were enrolled in Medicaid for ≥330 days and had ≥ one healthcare claim, and chlamydia tests by claims submitted in the 12 months prior to the survey interview.Of Medicaid women aged 18-25 years, 91.5% self-reported to be sexually-active. Of self-reported sexually-active women aged 18-25 years, 92.0% had ≥ one healthcare claim in the 12 months prior to the survey interview; of this subpopulation, only 58.8% were enrolled in Medicaid for ≥ 330 days in the 12 months prior to the survey interview; of this further subpopulation, 74.1% had healthcare claims identifying them as sexually-active in the 12 months prior to the survey interview. Of HEDIS-defined sexually-active women, 42.4% had chlamydia testing.Our study suggests that the number of sexually-active women aged 18-25 years used as the denominator in the chlamydia testing measure could be significantly different, depending upon the definition applied and the data used. Our data highlight the limited representativeness of Medicaid population in the current HEDIS measure on chlamydia testing when a high proportion of women who were enrolled in Medicaid for <330 days had been excluded from

  7. Understanding nature's particle accelerators using high energy gamma-ray survey instruments

    Science.gov (United States)

    Abeysekara, Anushka Udara

    Nature's particle accelerators, such as Pulsars, Pulsar Wind Nebulae, Active Galactic Nuclei and Supernova Remnants accelerate charged particles to very high energies that then produce high energy photons. The particle acceleration mechanisms and the high energy photon emission mechanisms are poorly understood phenomena. These mechanisms can be understood either by studying individual sources in detail or, alternatively, using the collective properties of a sample of sources. Recent development of GeV survey instruments, such as Fermi-LAT, and TeV survey instruments, such as Milagro, provides a large sample of high energy gamma-ray flux measurements from galactic and extra-galactic sources. In this thesis I provide constraints on GeV and TeV radiation mechanisms using the X-ray-TeV correlations and GeV-TeV correlations. My data sample was obtained from three targeted searches for extragalactic sources and two targeted search for galactic sources, using the existing Milagro sky maps. The first extragalactic candidate list consists of Fermi-LAT GeV extragalactic sources, and the second extragalactic candidate list consists of TeVCat extragalactic sources that have been detected by Imaging Atmospheric Cerenkov Telescopes (IACTs). In both extragalactic candidate lists Markarian 421 was the only source detected by Milagro. A comparison between the Markarian 421 time-averaged flux, measured by Milagro, and the flux measurements of transient states, measured by IACTs, is discussed. The third extragalactic candidate list is a list of potential TeV emitting BL Lac candidates that was synthesized using X-ray observations of BL Lac objects and a Synchrotron Self-Compton model. Milagro's sensitivity was not sufficient to detect any of those candidates. However, the 95% confidence flux upper limits of those sources were above the predicted flux. Therefore, these results provide evidence to conclude that the Synchrotron Self-Compton model for BL Lac objects is still a viable

  8. Computational Fluid Dynamics Modeling to Improve Natural Flow Rate and Sweet Pepper Productivity in Greenhouse

    Directory of Open Access Journals (Sweden)

    W. Limtrakarn

    2012-01-01

    Full Text Available Natural flow rate and sweet peppers productivity in tropical greenhouse are improved by CFD simulation is the main objective of this research work. Most of the greenhouse types today are in the arch shape. To develop an improved greenhouse structure for the region, the arch type was built and used as the control model. Mae Sar Mai agriculture research station under the royal project foundation was selected as the field test site. Temperature sensors with data logger were installed to monitor variation of temperature inside the greenhouse. The measured temperature data were used as the boundary conditions for the CFD analysis. A new greenhouse model with two-step roof shape was designed and the air flow behavior was simulated by using CFD. Regarding CFD results the air flow rate of the new model is about 39% higher than that of old model. The maximum temperature of the new model is lower than that of the old one. The sweet paper growths in both greenhouse models were measured and compared. Results show that the new model obtains 4°C lower maximum temperature in day time, 97% in number and 90% in weight higher the first grade pepper productivity than the old one.

  9. WATER HYACINTH: A POSSIBLE ALTERNATIVE RATE RETARDING NATURAL POLYMER USED IN SUSTAINED RELEASE TABLET DESIGN

    Directory of Open Access Journals (Sweden)

    Sabera eKhatun

    2014-06-01

    Full Text Available In recent years natural polymers have been widely used, because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5%, 10%, 15%, 20%, 25% and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr’s Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR, Differential Scanning Calorimetry (DSC and Scanning Electron Microscopy (SEM studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37oC ± 0.5 temperature, for 8 hours. All the formulations comply with both BP and USP requirements, but among all the formulations F-1 (5% of Water hyacinth was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations.

  10. Water hyacinth: a possible alternative rate retarding natural polymer used in sustained release tablet design

    Science.gov (United States)

    Khatun, Sabera; Sutradhar, Kumar B.

    2014-01-01

    In recent years natural polymers have been widely used because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5, 10, 15, 20, 25 and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr's Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37°C ± 0.5 temperature for 8 h. Though all the formulations comply with both BP and USP requirements, formulation F-1 (5% of Water hyacinth) was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell, and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations. PMID:24966835

  11. Water hyacinth: a possible alternative rate retarding natural polymer used in sustained release tablet design.

    Science.gov (United States)

    Khatun, Sabera; Sutradhar, Kumar B

    2014-01-01

    In recent years natural polymers have been widely used because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5, 10, 15, 20, 25 and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr's Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37°C ± 0.5 temperature for 8 h. Though all the formulations comply with both BP and USP requirements, formulation F-1 (5% of Water hyacinth) was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell, and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations.

  12. The relationship between nature of science understandings and science self-efficacy beliefs of sixth grade students

    Science.gov (United States)

    Parker, Elisabeth Allyn

    Bandura (1986) posited that self-efficacy beliefs help determine what individuals do with the knowledge and skills they have and are critical determinants of how well skill and knowledge are acquired. Research has correlated self-efficacy beliefs with academic success and subject interest (Pajares, Britner, & Valiante, 2000). Similar studies report a decreasing interest by students in school science beginning in middle school claiming that they don't enjoy science because the classes are boring and irrelevant to their lives (Basu & Barton, 2007). The hypothesis put forth by researchers is that students need to observe models of how science is done, the nature of science (NOS), so that they connect with the human enterprise of science and thereby raise their self-efficacy (Britner, 2008). This study examined NOS understandings and science self-efficacy of students enrolled in a sixth grade earth science class taught with explicit NOS instruction. The research questions that guided this study were (a) how do students' self-efficacy beliefs change as compared with changes in their nature of science understandings?; and (b) how do changes in students' science self-efficacy beliefs vary with gender and ethnicity segregation? A mixed method design was employed following an embedded experimental model (Creswell & Plano Clark, 2007). As the treatment, five NOS aspects were first taught by the teachers using nonintegrated activities followed by integrated instructional approach (Khishfe, 2008). Students' views of NOS using the Views on Nature of Science (VNOS) (Lederman, Abd-El-Khalick, & Schwartz, 2002) along with their self-efficacy beliefs using three Likert-type science self-efficacy scales (Britner, 2002) were gathered. Changes in NOS understandings were determined by categorizing student responses and then comparing pre- and post-instructional understandings. To determine changes in participants' self-efficacy beliefs as measured by the three subscales, a multivariate

  13. Understanding the Spatio-Temporal Response of Coral Reef Fish Communities to Natural Disturbances: Insights from Beta-Diversity Decomposition.

    Science.gov (United States)

    Lamy, Thomas; Legendre, Pierre; Chancerelle, Yannick; Siu, Gilles; Claudet, Joachim

    2015-01-01

    Understanding how communities respond to natural disturbances is fundamental to assess the mechanisms of ecosystem resistance and resilience. However, ecosystem responses to natural disturbances are rarely monitored both through space and time, while the factors promoting ecosystem stability act at various temporal and spatial scales. Hence, assessing both the spatial and temporal variations in species composition is important to comprehensively explore the effects of natural disturbances. Here, we suggest a framework to better scrutinize the mechanisms underlying community responses to disturbances through both time and space. Our analytical approach is based on beta diversity decomposition into two components, replacement and biomass difference. We illustrate this approach using a 9-year monitoring of coral reef fish communities off Moorea Island (French Polynesia), which encompassed two severe natural disturbances: a crown-of-thorns starfish outbreak and a hurricane. These disturbances triggered a fast logistic decline in coral cover, which suffered a 90% decrease on all reefs. However, we found that the coral reef fish composition remained largely stable through time and space whereas compensatory changes in biomass among species were responsible for most of the temporal fluctuations, as outlined by the overall high contribution of the replacement component to total beta diversity. This suggests that, despite the severity of the two disturbances, fish communities exhibited high resistance and the ability to reorganize their compositions to maintain the same level of total community biomass as before the disturbances. We further investigated the spatial congruence of this pattern and showed that temporal dynamics involved different species across sites; yet, herbivores controlling the proliferation of algae that compete with coral communities were consistently favored. These results suggest that compensatory changes in biomass among species and spatial

  14. Changes in Pre-Service Science Teachers' Understandings After Being Involved in Explicit Nature of Science and Socioscientific Argumentation Processes

    Science.gov (United States)

    Kutluca, A. Y.; Aydin, A.

    2017-01-01

    The study explored the changes in pre-service science teachers' understanding of the nature of science and their opinions about the nature of science, science teaching and argumentation after their participation in explicit nature of science (NOS) and socioscientific argumentation processes. The participants were 56 third-grade pre-service science…

  15. Natural radionuclide content in building materials and gamma dose rate in dwellings in Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Brigido Flores, O. [Department of Applied Nuclear Techniques and Environmental Monitoring, Environmental Engineering Centre of Camagoeey, Ave. Finlay km 2.5, Esquina Circunvalacion, Rpto. Puerto Principe, Camagueey 8, CP 70800, Camagueey (Cuba)], E-mail: o.brigido@ciac.cmw.inf.cu; Montalvan Estrada, A.; Rosa Suarez, R. [Department of Applied Nuclear Techniques and Environmental Monitoring, Environmental Engineering Centre of Camagoeey, Ave. Finlay km 2.5, Esquina Circunvalacion, Rpto. Puerto Principe, Camagueey 8, CP 70800, Camagueey (Cuba); Tomas Zerquera, J. [Centre for Radiation Protection and Hygiene, 20 St. No. 4109, Miramar, PO Box 6195, Havana 6, Havana City (Cuba); Hernandez Perez, A. [Environmental Radiological Monitoring Laboratory, Centre for Environmental Studies of Holguin, Pachuco Feria No. 46, Rpto. Peralta, Holguin (Cuba)

    2008-12-15

    An extensive research project to investigate the radioactive properties of Cuban building materials was carried out because there is a lack of information on the radioactivity of such materials in Cuba. In the framework of this project 44 samples of commonly used raw materials and building products were collected in five Cuban provinces. The activity concentrations of natural radionuclides were determined by gamma ray spectrometry using a p-type coaxial high purity germanium detector and their mean values were in the ranges: 9-857 Bq kg{sup -1} for {sup 40}K; 6-57 Bq kg{sup -1} for {sup 226}Ra; and 1.2-22 Bq kg{sup -1} for {sup 232}Th. The radium equivalent activity in the 44 samples varied from 4 Bq kg{sup -1} (wood) to 272 Bq kg{sup -1} (brick). A high pressure ionisation chamber was used to measure the indoor absorbed dose rate in 543 dwellings and workplaces in five Cuban provinces. The average absorbed dose rates in air ranged from 43 nGy h{sup -1} (Holguin) to 73 nGy h{sup -1} (Camagueey) and the corresponding population-weighted annual effective dose due to external gamma radiation was estimated to be 145 {+-} 40 {mu}Sv. This value is 51% lower than the effective dose due to internal exposure from inhalation of decay products of {sup 222}Rn and {sup 220}Rn and it is 16% higher than the calculated value for the typical room geometry of a Cuban house.

  16. Comparing facility-level methane emission rate estimates at natural gas gathering and boosting stations

    Directory of Open Access Journals (Sweden)

    Timothy L. Vaughn

    2017-11-01

    Full Text Available Coordinated dual-tracer, aircraft-based, and direct component-level measurements were made at midstream natural gas gathering and boosting stations in the Fayetteville shale (Arkansas, USA. On-site component-level measurements were combined with engineering estimates to generate comprehensive facility-level methane emission rate estimates (“study on-site estimates (SOE” comparable to tracer and aircraft measurements. Combustion slip (unburned fuel entrained in compressor engine exhaust, which was calculated based on 111 recent measurements of representative compressor engines, accounts for an estimated 75% of cumulative SOEs at gathering stations included in comparisons. Measured methane emissions from regenerator vents on glycol dehydrator units were substantially larger than predicted by modelling software; the contribution of dehydrator regenerator vents to the cumulative SOE would increase from 1% to 10% if based on direct measurements. Concurrent measurements at 14 normally-operating facilities show relative agreement between tracer and SOE, but indicate that tracer measurements estimate lower emissions (regression of tracer to SOE = 0.91 (95% CI = 0.83–0.99, R2 = 0.89. Tracer and SOE 95% confidence intervals overlap at 11/14 facilities. Contemporaneous measurements at six facilities suggest that aircraft measurements estimate higher emissions than SOE. Aircraft and study on-site estimate 95% confidence intervals overlap at 3/6 facilities. The average facility level emission rate (FLER estimated by tracer measurements in this study is 17–73% higher than a prior national study by Marchese et al.

  17. Constraints on the magnitude and rate of CO2 dissolution at Bravo Dome natural gas field.

    Science.gov (United States)

    Sathaye, Kiran J; Hesse, Marc A; Cassidy, Martin; Stockli, Daniel F

    2014-10-28

    The injection of carbon dioxide (CO2) captured at large point sources into deep saline aquifers can significantly reduce anthropogenic CO2 emissions from fossil fuels. Dissolution of the injected CO2 into the formation brine is a trapping mechanism that helps to ensure the long-term security of geological CO2 storage. We use thermochronology to estimate the timing of CO2 emplacement at Bravo Dome, a large natural CO2 field at a depth of 700 m in New Mexico. Together with estimates of the total mass loss from the field we present, to our knowledge, the first constraints on the magnitude, mechanisms, and rates of CO2 dissolution on millennial timescales. Apatite (U-Th)/He thermochronology records heating of the Bravo Dome reservoir due to the emplacement of hot volcanic gases 1.2-1.5 Ma. The CO2 accumulation is therefore significantly older than previous estimates of 10 ka, which demonstrates that safe long-term geological CO2 storage is possible. Integrating geophysical and geochemical data, we estimate that 1.3 Gt CO2 are currently stored at Bravo Dome, but that only 22% of the emplaced CO2 has dissolved into the brine over 1.2 My. Roughly 40% of the dissolution occurred during the emplacement. The CO2 dissolved after emplacement exceeds the amount expected from diffusion and provides field evidence for convective dissolution with a rate of 0.1 g/(m(2)y). The similarity between Bravo Dome and major US saline aquifers suggests that significant amounts of CO2 are likely to dissolve during injection at US storage sites, but that convective dissolution is unlikely to trap all injected CO2 on the 10-ky timescale typically considered for storage projects.

  18. The Cultural Argument for Understanding Nature of Science. A Chance to Reflect on Similarities and Differences Between Science and Humanities

    Science.gov (United States)

    Reiners, Christiane S.; Bliersbach, Markus; Marniok, Karl

    2017-07-01

    Understanding Nature of Science (NOS) is a central component of scientific literacy, which is agreed upon internationally, and consequently has been a major educational goal for many years all over the globe. In order to justify the promotion of an adequate understanding of NOS, educators have developed several arguments, among them the cultural argument. But what is behind this argument? In order to answer this question, C. P. Snow's vision of two cultures was used as a starting point. In his famous Rede Lecture from 1959, he complained about a wide gap between the arts and humanities on the one hand and sciences on the other hand. While the representatives of the humanities refer to themselves as real intellectuals, the scientists felt rather ignored as a culture, despite the fact that their achievements had been so important for Western society. Thus, Snow argued that as these intellectual cultures were completely different from each other, a mutual understanding was impossible. The first European Regional IHPST Conference took up the cultural view on science again. Thus, the topic of the conference "Science as Culture in the European Context" encouraged us to look at the two cultures and to figure out possibilities to bridge the gap between them in chemistry teacher education. For this reason, we put together three studies—one theoretical and two independent research projects (one dealing with creativity in science, the other with scientific laws and theories) which contribute to our main research field (promoting an understanding of NOS)—in order to address the cultural argument for understanding science from an educational point of view. Among the consented tenets of what understanding NOS implies in an educational context, there are aspects which are associated mainly with the humanities, like the tentativeness of knowledge, creativity, and social tradition, whereas others seem to have a domain-specific meaning, like empirical evidence, theories and laws

  19. Understanding natural capital

    Science.gov (United States)

    Stallard, Robert F.; Hall, Jefferson S.; Kirn, Vanessa; Yanguas-Fernandez, Estrella

    2015-01-01

    This chapter serves to introduce the geophysics of Neotropical steeplands. Topics are covered in a general manner with hyperlinks to active research and monitoring sites (such as the National Hurricane Center and US Geological Survey publication). Topics covered include ‘tropical climate and weather,’ ‘climate variations and trends,’ Neotropical ‘geology, and soils,’ ‘hillslopes and erosion,’ ‘lakes and reservoirs,’ and ‘effects of land cover on water quality and quantity.’ Obviously, this is a lot of information to cover in a short chapter, hence the use of hyperlinks. The last theme ‘effects of land cover on water quality and quantity’ is covered by case studies, in all of which I have been centrally involved. These studies were chosen because they are among the few studies with sufficient data of high enough quality to reach definitive conclusions.

  20. Experimental investigation of angular distributions of exposure rate in natural environments

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Sakamoto, Ryuichi; Saito, Kimiaki; Moriuchi, Shigeru

    1981-01-01

    Angular distributions of exposure rate in natural radiation environment were measured using a 1''diameter x 1'' NaI(Tl) scintillation detector which was placed on the axis of a set of concentric circular lead shieldings. Incident polar angle of γ ray was determined by changing the relative position between the detector and the shieldings. Incident γ rays were integrated over the whole azimuthal angle (0 - 2π) in each polar angle. And then, the angular distribution was obtained by subtracting the responses between each polar angle. As the incident solid angle of γ ray could be set large enough, it was possible not only to set the measuring time short but also to measure with high accuracy. Measurements were made under various environmental conditions; two on open field and one in a pine grove at a height of 1 m, and one at a height of 10 m on a tower. And also, one measurement was made in a one-storied wooden house. Experimental results supported the angular distributions expected from calculations, previously reported by other authors, and it was shown that this method can be applied well even where a calculational evaluation is difficult due to the complexity of its topography. (author)

  1. Phylogenetic analysis of standard metabolic rate of snakes: a new proposal for the understanding of interspecific variation in feeding behavior.

    Science.gov (United States)

    Stuginski, Daniel Rodrigues; Navas, Carlos Arturo; de Barros, Fábio Cury; Camacho, Agustín; Bicudo, José Eduardo Pereira Wilken; Grego, Kathleen Fernandes; de Carvalho, José Eduardo

    2017-10-06

    The current proposal about the variation of standard metabolic rates (SMR) in snakes predicts that SMR is influenced by the feeding frequency (frequent or infrequent feeders). However, feeding frequency in snakes is poorly studied and hard to quantify under natural conditions. Alternatively, foraging strategy was studied for a large number of species and is usually related to the feeding frequency. In this work, we performed a meta-analysis on the SMR of compiled data from 74 species of snakes obtained from the literature and five more different species of lanceheads (genus Bothrops), after categorization according to the foraging mode (ambush or active foraging) and regarding their phylogenetic history. We tested the hypothesis that foraging mode (FM) is a determinant factor on the interspecific variation of SMR despite the phylogenetic relationship among species. We demonstrated that FM predicted SMR, but there is also a partial phylogenetic structuration of SMR in snakes. We also detected that evolution rates of SMR in active foragers seem to be higher than ambush-hunting snakes. We suggested that foraging mode has a major effect over the evolution of SMR in snakes, which could represent an ecophysiological co-adaptation, since ambush hunters (with low feeding rates) present a lower maintenance energetic cost (SMR) when compared to active foragers. The higher SMR evolution rates for active foraging snakes could be related to a higher heterogeny in the degree of activity during hunting by active foragers when compared to ambush-hunting snakes.

  2. Association between objective measurement of the speech intelligibility of young people with dysarthria and listener ratings of ease of understanding.

    Science.gov (United States)

    Landa, Sophie; Pennington, Lindsay; Miller, Nick; Robson, Sheila; Thompson, Vicki; Steen, Nick

    2014-08-01

    This study aimed to investigate the association between listeners' ratings of how much effort it took to understand the speech of young people with cerebral palsy and the percentage of words listeners actually understood. Thirty-one young people with dysarthria and cerebral palsy (16 males, 15 females; mean age = 11 years, SD = 3) were audio recorded repeating single words and producing speech. Objective measures of intelligibility were calculated for multiple familiar and unfamiliar listeners using a forced choice paradigm for single words and verbatim orthographic transcriptions for connected speech. Listeners rated how much effort it took to understand speech in each condition using a 5-point ordinal ease of listening (EOL) scale. Agreement on EOL within rater groups was high (ICC > 0.71). An effect of listener was observed for familiar listeners, but not for unfamiliar listeners. EOL agreement between familiar and unfamiliar listeners was weak-moderate (ICC = 0.46). EOL predicted the percentage of speech actually understood by familiar and unfamiliar listeners (r > 0.56, p < 0.001 for all predictions). Strongest associations between EOL and intelligibility were observed for speakers with mild and profound impairments. The findings of this study demonstrate that listeners can judge how well they have understood dysarthric speech. EOL is associated with listener familiarity, speech task and speech impairment severity. EOL is appropriate for use in clinical practice as a measure of communication activity.

  3. Rating

    OpenAIRE

    Karas, Vladimír

    2006-01-01

    Charakteristika ratingu. Dělení a druhy ratingu (rating emise × rating emitenta; dlouhodobý rating × krátkodobý rating; mezinárodní rating × lokální rating). Obecné požadavky kladené na rating. Proces tvorby ratingu. Vyžádaný rating. Nevyžádaný rating. Ratingový proces na bázi volně přístupných informací. Uplatňované ratingové systémy. Ratingová kriteria. Využití a interpretace ratingové známky. Funkce ratingu. Rating v souvislosti s BASEL II. Rating v souvislosti s hospodářskými krizemi....

  4. Neutralization of Bothrops asper venom by antibodies, natural products and synthetic drugs: contributions to understanding snakebite envenomings and their treatment.

    Science.gov (United States)

    Lomonte, Bruno; León, Guillermo; Angulo, Yamileth; Rucavado, Alexandra; Núñez, Vitelbina

    2009-12-01

    Interest in studies on the neutralization of snake venoms and toxins by diverse types of inhibitors is two-fold. From an applied perspective, results enclose the potential to be translated into useful therapeutic products or procedures, to benefit patients suffering from envenomings. From a basic point of view, on the other hand, neutralizing agents may be used as powerful dissecting tools to determine the relative role of toxins within the context of the overall pathology induced by a venom, or to increase our understanding on the molecular mechanisms by which toxins exert their harmful actions upon particular targets. The venom of the snake Bothrops asper has been the subject of a number of experimental studies addressing its neutralization by antibodies, as well as by non-immunologic inhibitors, including natural products derived from plants or animals, or synthetic drugs. As summarized in the present review, neutralization studies on this venom and some of its isolated toxins have contributed to a better understanding of envenomings by this species, and their treatment. In addition, such studies have provided valuable knowledge on the mechanisms of action and the relative functional importance of particular toxins of this venom, especially in the case of its myotoxic phospholipases A(2) and hemorrhagic metalloproteinases.

  5. Novel approach for evaluation of air change rate in naturally ventilated occupied spaces based on metabolic CO2 time variation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Markov, Detelin G.

    2014-01-01

    IAQ in many residential buildings relies on non-organized natural ventilation. Accurate evaluation of air change rate (ACR) in this situation is difficult due to the nature of the phenomenon - intermittent infiltration-exfiltration periods of mass exchange between the room air and the outdoor air...... at low rate. This paper describes a new approach for ACR evaluation in naturally ventilated occupied spaces. Actual metabolic CO2 time variation record in an interval of time is compared with the computed variation of metabolic CO2 for the same time interval under reference conditions: sleeping occupants......, air-tight space, constant indoor pressure and temperature. The proposed approach for ACR evaluation can be applied to time intervals with any length, even with varying parameters of both indoor and outdoor air, in which metabolic CO2 generation rate is known and constant. This approach makes possible...

  6. Rate of formation and dissolution of mercury sulfide nanoparticles: The dual role of natural organic matter

    Science.gov (United States)

    Slowey, Aaron J.

    2010-01-01

    Mercury is a global contaminant of concern due to its transformation by microorganisms to form methylmercury, a toxic species that accumulates in biological tissues. The effect of dissolved organic matter (DOM) isolated from natural waters on reactions between mercury(II) (Hg) and sulfide (S(-II)) to form HgS(s) nanoparticles across a range of Hg and S(-II) concentrations was investigated. Hg was equilibrated with DOM, after which S(-II) was added. Dissolved Hg (Hgaq) was periodically quantified using ultracentrifugation and chemical analysis following the addition of S(-II). Particle size and identity were determined using dynamic light scattering and X-ray absorption spectroscopy. S(-II) reacts with Hg to form 20 to 200nm aggregates consisting of 1-2 nm HgS(s) subunits that are more structurally disordered than metacinnabar in the presence of 2 x 10-9 to 8 x 10-6M Hg and 10 (mg C)L-1 DOM. Some of the HgS(s) nanoparticle aggregates are subsequently dissolved by DOM and (re)precipitated by S(-II) over periods of hours to days. At least three fractions of Hg-DOM species were observed with respect to reactivity toward S(-II): 0.3 μmol reactive Hg per mmol C (60 percent), 0.1 μmol per mmol C (20 percent) that are kinetically hindered, and another 0.1 μmol Hg per mmol C (20 percent) that are inert to reaction with S(-II). Following an initial S(-II)-driven precipitation of HgS(s), HgS(s) was dissolved by DOM or organic sulfur compounds. HgS(s) formation during this second phase was counterintuitively favored by lower S(-II) concentrations, suggesting surface association of DOM moieties that are less capable of dissolving HgS(s). DOM partially inhibits HgS(s) formation and mediates reactions between Hg and S(-II) such that HgS(s) is susceptible to dissolution. These findings indicate that Hg accessibility to microorganisms could be controlled by kinetic (intermediate) species in the presence of S(-II) and DOM, undermining the premise that equilibrium Hg species

  7. Estimated human excretion rates of natural estrogens calculated from their concentrations in raw municipal wastewater and its application.

    Science.gov (United States)

    Liu, Ze-Hua; Lu, Gui-Ning; Yin, Hua; Dang, Zhi

    2015-06-01

    Natural estrogens are important endocrine disrupting compounds (EDCs), which may pose adverse effects on our environment. To avoid time-consuming sample preparation and chemical analysis, estimation of their concentrations in municipal wastewater based on their human urine/feces excretion rates has been generally adopted. However, the data of excretion rates available are very limited and show significant difference among countries. In the context of increasing reporting on the concentrations of natural estrogens in municipal wastewater around the world, this study presented a simple method to estimate their human excretion rates based on the concentrations of natural estrogens in raw sewage. The estimated human excretion rates of natural estrogens among ten countries were obtained, which totally covered over 33 million population. Among these, Brazilians had the largest excretion rates with estrone (E1) and 17β-estradiol (E2) as 236.9 and 60 μg/day/P, respectively, while Iran had the lowest value of 2 μg/day/P for E1 and 0.5 μg/day/P for E2. The average estimated human excretion rates of E1, E2, and estriol (E3) are 17.3, 6.4, and 39.7 μg/day/P, respectively. When the estimated human excretion rates obtained were applied for prediction, the predicted results showed better accuracies than those based on human urinary/feces excretion rates. The method in this study is simple, cost-effective and time-saving, which may be widely applied.

  8. Application of the SP theory of intelligence to the understanding of natural vision and the development of computer vision.

    Science.gov (United States)

    Wolff, J Gerard

    2014-01-01

    The SP theory of intelligence aims to simplify and integrate concepts in computing and cognition, with information compression as a unifying theme. This article is about how the SP theory may, with advantage, be applied to the understanding of natural vision and the development of computer vision. Potential benefits include an overall simplification of concepts in a universal framework for knowledge and seamless integration of vision with other sensory modalities and other aspects of intelligence. Low level perceptual features such as edges or corners may be identified by the extraction of redundancy in uniform areas in the manner of the run-length encoding technique for information compression. The concept of multiple alignment in the SP theory may be applied to the recognition of objects, and to scene analysis, with a hierarchy of parts and sub-parts, at multiple levels of abstraction, and with family-resemblance or polythetic categories. The theory has potential for the unsupervised learning of visual objects and classes of objects, and suggests how coherent concepts may be derived from fragments. As in natural vision, both recognition and learning in the SP system are robust in the face of errors of omission, commission and substitution. The theory suggests how, via vision, we may piece together a knowledge of the three-dimensional structure of objects and of our environment, it provides an account of how we may see things that are not objectively present in an image, how we may recognise something despite variations in the size of its retinal image, and how raster graphics and vector graphics may be unified. And it has things to say about the phenomena of lightness constancy and colour constancy, the role of context in recognition, ambiguities in visual perception, and the integration of vision with other senses and other aspects of intelligence.

  9. Using a Professional Development Program for Enhancing Chilean Biology Teachers' Understanding of Nature of Science (NOS) and Their Perceptions about Using History of Science to Teach NOS

    Science.gov (United States)

    Pavez, José M.; Vergara, Claudia A.; Santibañez, David; Cofré, Hernán

    2016-01-01

    A number of authors have recognized the importance of understanding the nature of science (NOS) for scientific literacy. Different instructional strategies such as decontextualized, hands-on inquiry, and history of science (HOS) activities have been proposed for teaching NOS. This article seeks to understand the contribution of HOS in enhancing…

  10. Effect of Dose Rate on Radiation Pre vulcanized Natural Rubber Latex Tensile Strength and Physical Properties

    International Nuclear Information System (INIS)

    Sofian Ibrahim; Mohd Noorwadi Mat Lazim; Syuhada Ramli

    2015-01-01

    Comparison on effect of irradiation dose rate on physical and mechanical properties of RVNRL was carried out in RAYMINTEX and Sinagama plant with dose rate at 0.23 kGy/ hour and 2.00 kGy/ hour respectively. The samples were irradiated at 12, 15 and 17 kGy. Results from the study showed irradiation dose rate does not significantly affect on physical properties of RVNRL but affects its tensile strength approximately at 10-15 %. Therefore it can be concluded that high irradiation dose rates will produced RVNRL with better tensile strength. (author)

  11. Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA.

    Science.gov (United States)

    Lavelle, Michael J; Kay, Shannon L; Pepin, Kim M; Grear, Daniel A; Campa, Henry; VerCauteren, Kurt C

    2016-12-01

    Direct and indirect contacts among individuals drive transmission of infectious disease. When multiple interacting species are susceptible to the same pathogen, risk assessment must include all potential host species. Bovine tuberculosis (bTB) is an example of a disease that can be transmitted among several wildlife species and to cattle, although the potential role of several wildlife species in spillback to cattle remains unclear. To better understand the complex network of contacts and factors driving disease transmission, we fitted proximity logger collars to beef and dairy cattle (n=37), white-tailed deer (Odocoileus virginianus; n=29), raccoon (Procyon lotor; n=53), and Virginia opossum (Didelphis virginiana; n=79) for 16 months in Michigan's Lower Peninsula, USA. We determined inter- and intra-species direct and indirect contact rates. Data on indirect contact was calculated when collared animals visited stationary proximity loggers placed at cattle feed and water resources. Most contact between wildlife species and cattle was indirect, with the highest contact rates occurring between raccoons and cattle during summer and fall. Nearly all visits (>99%) to cattle feed and water sources were by cattle, whereas visitation to stored cattle feed was dominated by deer and raccoon (46% and 38%, respectively). Our results suggest that indirect contact resulting from wildlife species visiting cattle-related resources could pose a risk of disease transmission to cattle and deserves continued attention with active mitigation. Published by Elsevier B.V.

  12. National survey on the natural radioactivity and Rn-222 exhalation rate of building materials in the Netherlands

    NARCIS (Netherlands)

    de Jong, P.; van Dijk, W.; van der Graaf, E.R.; de Groot, A.V.

    The present study reports on results of a nationwide survey on the natural radioactivity concentrations and Rn-222 exhalation rates of the prevailing building materials in the Netherlands. In total 100 samples were taken and analyzed for the activity concentrations of Ra-226, Ra-228, Th-228, and

  13. Understanding the Nature of Science Through a Critical and Reflective Analysis of the Controversy Between Pasteur and Liebig on Fermentation

    Science.gov (United States)

    García-Carmona, Antonio; Acevedo-Díaz, José Antonio

    2017-03-01

    This article presents a qualitative study, descriptive-interpretive in profile, of the effectiveness in learning about the nature of science (NOS) of an activity relating to the historical controversy between Pasteur and Liebig on fermentation. The activity was implemented during a course for pre-service secondary science teachers (PSSTs) specializing in physics and chemistry. The approach was explicit and reflective. Three research questions were posed: (1) What conceptions of NOS do the PSSTs show after a first reflective reading of the historical controversy?, (2) What role is played by the PSSTs' whole class critical discussion of their first reflections on the aspects of NOS dealt with in the controversy?, and (3) What changes are there in the PSSTs' conceptions of NOS after concluding the activity? The data for analysis was extracted from the PSSTs' group reports submitted at the end of the activity and the audio-recorded information from the whole class discussion. A rubric was prepared to assess this data by a process of inter-rater analysis. The results showed overall improvement in understanding the aspects of NOS involved, with there being a significant evolution in some cases (e.g., conception of scientific theory) and moderate in others (e.g., differences in scientific interpretations of the same phenomenon). This reveals that the activity has an educational utility for the education of PSSTs in NOS issues. The article concludes with an indication of some educational implications of the experience.

  14. Molecular phenology in plants: in natura systems biology for the comprehensive understanding of seasonal responses under natural environments.

    Science.gov (United States)

    Kudoh, Hiroshi

    2016-04-01

    Phenology refers to the study of seasonal schedules of organisms. Molecular phenology is defined here as the study of the seasonal patterns of organisms captured by molecular biology techniques. The history of molecular phenology is reviewed briefly in relation to advances in the quantification technology of gene expression. High-resolution molecular phenology (HMP) data have enabled us to study phenology with an approach of in natura systems biology. I review recent analyses of FLOWERING LOCUS C (FLC), a temperature-responsive repressor of flowering, along the six steps in the typical flow of in natura systems biology. The extensive studies of the regulation of FLC have made this example a successful case in which a comprehensive understanding of gene functions has been progressing. The FLC-mediated long-term memory of past temperatures creates time lags with other seasonal signals, such as photoperiod and short-term temperature. Major signals that control flowering time have a phase lag between them under natural conditions, and hypothetical phase lag calendars are proposed as mechanisms of season detection in plants. Transcriptomic HMP brings a novel strategy to the study of molecular phenology, because it provides a comprehensive representation of plant functions. I discuss future perspectives of molecular phenology from the standpoints of molecular biology, evolutionary biology and ecology. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.

  15. When nature's robots go rogue: exploring protein homeostasis dysfunction and the implications for understanding human aging disease pathologies.

    Science.gov (United States)

    Reisz, Julie A; Barrett, Alexander S; Nemkov, Travis; Hansen, Kirk C; D'Alessandro, Angelo

    2018-03-14

    Proteins have been historically regarded as "nature's robots": Molecular machines that are essential to cellular/extracellular physical mechanical properties and catalyze key reactions for cell/system viability. However, these robots are kept in check by other protein-based machinery to preserve proteome integrity and stability. During aging, protein homeostasis is challenged by oxidation, decreased synthesis, and increasingly inefficient mechanisms responsible for repairing or degrading damaged proteins. In addition, disruptions to protein homeostasis are hallmarks of many neurodegenerative diseases and diseases disproportionately affecting the elderly. Areas covered: Here we summarize age- and disease-related changes to the protein machinery responsible for preserving proteostasis and describe how both aging and disease can each exacerbate damage initiated by the other. We focus on alteration of proteostasis as an etiological or phenomenological factor in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's, along with Down syndrome, ophthalmic pathologies, and cancer. Expert commentary: Understanding the mechanisms of proteostasis and their dysregulation in health and disease will represent an essential breakthrough in the treatment of many (senescence-associated) pathologies. Strides in this field are currently underway and largely attributable to the introduction of high-throughput omics technologies and their combination with novel approaches to explore structural and cross-link biochemistry.

  16. Surmounting the Tower of Babel: Monolingual and bilingual 2-year-olds' understanding of the nature of foreign language words.

    Science.gov (United States)

    Byers-Heinlein, Krista; Chen, Ke Heng; Xu, Fei

    2014-03-01

    Languages function as independent and distinct conventional systems, and so each language uses different words to label the same objects. This study investigated whether 2-year-old children recognize that speakers of their native language and speakers of a foreign language do not share the same knowledge. Two groups of children unfamiliar with Mandarin were tested: monolingual English-learning children (n=24) and bilingual children learning English and another language (n=24). An English speaker taught children the novel label fep. On English mutual exclusivity trials, the speaker asked for the referent of a novel label (wug) in the presence of the fep and a novel object. Both monolingual and bilingual children disambiguated the reference of the novel word using a mutual exclusivity strategy, choosing the novel object rather than the fep. On similar trials with a Mandarin speaker, children were asked to find the referent of a novel Mandarin label kuò. Monolinguals again chose the novel object rather than the object with the English label fep, even though the Mandarin speaker had no access to conventional English words. Bilinguals did not respond systematically to the Mandarin speaker, suggesting that they had enhanced understanding of the Mandarin speaker's ignorance of English words. The results indicate that monolingual children initially expect words to be conventionally shared across all speakers-native and foreign. Early bilingual experience facilitates children's discovery of the nature of foreign language words. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Novel targeted approach to better understand how natural structural barriers govern carotenoid in vitro bioaccessibility in vegetable-based systems.

    Science.gov (United States)

    Palmero, Paola; Lemmens, Lien; Ribas-Agustí, Albert; Sosa, Carola; Met, Kristof; de Dieu Umutoni, Jean; Hendrickx, Marc; Van Loey, Ann

    2013-12-01

    An experimental approach, allowing us to understand the effect of natural structural barriers (cell walls, chromoplast substructures) on carotenoid bioaccessibility, was developed. Different fractions with different levels of carotenoid bio-encapsulation (carotenoid-enriched oil, chromoplasts, small cell clusters, and large cell clusters) were isolated from different types of carrots and tomatoes. An in vitro method was used to determine carotenoid bioaccessibility. In the present work, a significant decrease in carotenoid in vitro bioaccessibility could be observed with an increasing level of bio-encapsulation. Differences in cell wall material and chromoplast substructure between matrices influenced carotenoid release and inclusion in micelles. For carrots, cell walls and chromoplast substructure were important barriers for carotenoid bioaccessibility while, in tomatoes, the chromoplast substructure represented the most important barrier governing bioaccessibility. The highest increase in carotenoid bioaccessibility, for all matrices, was obtained after transferring carotenoids into the oil phase, a system lacking cell walls and chromoplast substructures that could hamper carotenoid release. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Quantifying the Industrial Facility-Level Emission Rate of Methane in Various Segments of the Natural Gas Industry

    Science.gov (United States)

    Herndon, S. C.; Roscioli, J. R.; Yacovitch, T. I.; Floerchinger, C. R.; Mitchell, A.; Tkacik, D. S.; Subramanian, R.; Robinson, A. L.; Martinez, D. M.; Vaughn, T. L.; Williams, L.; Zimmerle, D.; Marchese, A.

    2014-12-01

    Methane, the dominant component in natural gas, is a potent short-lived radiative forcer. Recent technological advances in the extraction of oil and gas have increased the production rate dramatically since early 2000. In the context of CO2 emissions per energy generated, natural gas promises a tantalizing thermodynamic advantage over coal and other hydrocarbons. Natural gas emissions to the atmosphere along the entire path from well to customer, however, can wipe out the radiative forcing advantage once they surpass a threshold fraction of distributed gas. Recent studies have been undertaken to assess the methane emissions at various types of facilities within different sectors of the oil and gas industry. The distribution of observed facility level emission rates along with other results and conclusions from those studies will be presented. The implications that these findings have on the emissions inventories from these sectors will be discussed.

  19. Natural and anthropogenic radionuclide distributions in the Nansen Basin, Artic Ocean: Scavenging rates and circulation timescales

    Science.gov (United States)

    Kirk Cochran, J.; Hirschberg, David J.; Livingston, Hugh D.; Buesseler, Ken O.; Key, Robert M.

    Determination of the naturally occurring radionuclides 232Th, 230Th, 228 Th and 210Pb, and the anthropogenic radionuclides 241Am, 239,240Pu, 134Cs and 137Cs in water samples collected across the Nansen Basin from the Barents Sea slope to the Gakkel Ridge provides tracers with which to characterize both scavenging rates and circulation timescales in this portion of the Arctic Ocean. Large volume water samples (˜ 15001) were filtered in situ to separate particulate (> 0.5 μm) and dissolved Th isotopes and 241Am. Thorium-230 displays increases in both particulate and dissolved activities with depth, with dissolved 230Th greater and particulate 230Th lower in the deep central Nansen Basin than at the Barents Sea slope. Dissolved 228Th activities also are greater relative to 228Ra, in the central basin. Residence times for Th relative to removal from solution onto particles are ˜1 year in surface water, ˜10 years in deep water adjacent to the Barents Sea slope, and ˜20 years in the Eurasian Basin Deep Water. Lead-210 in the central basin deep water also has a residence time of ˜20 years with respect to its removal from the water column. This texture of scavenging is reflected in distributions of the particle-reactive anthropogenic radionuclide 241Am, which shows higher activities relative to Pu in the central Nansen Basin than at the Barents Sea slope. Distributions Of 137Cs show more rapid mixing at the basin margins (Barents Sea slope in the south, Gakkel Ridge in the north) than in the basin interior. Cesium-137 is mixed throughout the water column adjacent to the Barents Sea slope and is present in low but detectable activities in the Eurasian Basin Deep Water in the central basin. At the time of sampling (1987) the surface water at all stations had been labeled with 134Cs released in the 1986 accident at the Chernobyl nuclear power station. In the ˜1 year since the introduction of Chernobyl 134Cs to the Nansen Basin, it had been mixed to depths of ˜800 m at

  20. Erosion rates of wood during natural weathering. Part I, Effects of grain angle and surface texture

    Science.gov (United States)

    R. Sam Williams; Mark T. Knaebe; Peter G. Sotos; William C. Feist

    2001-01-01

    This is the first in a series of reports on the erosion rates of wood exposed outdoors near Madison, Wisconsin. The specimens were oriented vertically, facing south; erosion was measured annually for the first several years and biannually for the remainder of the exposure. In the work reported here, the erosion rates of earlywood and latewood were determined for smooth...

  1. The Relationship between Understanding of the Nature of Science and Practice: The influence of teachers' beliefs about education, teaching and learning

    Science.gov (United States)

    Waters-Adams, Stephen

    2006-06-01

    This paper reports the relationship between four English primary teachers’ understanding of the nature of science and their practice. Action research was included as a major part of the research design in order to explore the dialectical interplay between various factors at work in the teachers’ practice. The influences of both tacit and espoused understandings of the nature of science were considered alongside the teachers’ beliefs about education, teaching, and learning. These beliefs were found to be the determining factor in the teachers’ decisions about classroom strategies. In arguing for a dialectical perspective on teachers’ practice, the research suggests that teachers’ espoused understanding of the nature of science may also be at least partially formed by the influence of these beliefs, raising the possibility that influence may run from teaching to theoretical understanding and not the other way round.

  2. Study of natural radioactivity and 222Rn exhalation rate in soil samples for the assessment of average effective dose

    International Nuclear Information System (INIS)

    Bangotra, P.; Mehra, R.; Jakhu, R.; Sahoo, B.K

    2016-01-01

    The natural radioactivity in soil is usually determined from the 226 Ra (Radium), 232 Th (Thorium) and 40 K (potassium). 222 Rn and 220 Rn are produced in soil as a result of the presence of these radionuclides. As 226 Ra decay, the newly created 222 Rn radionuclide recoil from the parent grain and then exhale through the soil. Since 98.5% of radiological effects of 238 U series are produced by 226 Ra and its daughter products. The assessment of gamma radiation dose from natural sources is of particular importance as natural radiation is the largest contributor to the external dose of the world population. Authors are advised to maximize the information content utilizing the full space available. The main objective of the present study is to measure the level of natural radioactivity 226 Ra, 232 Th, 40 K and 222 Rn exhalation rate in the soil samples for health risk assessment

  3. Determination of photoformation rates and scavenging rate constants of hydroxyl radicals in natural waters using an automatic light irradiation and injection system

    Energy Technology Data Exchange (ETDEWEB)

    Nakatani, Nobutake [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan)]. E-mail: nnakatan@hiroshima-u.ac.jp; Hashimoto, Norichika [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan); Shindo, Hirotaka [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan); Yamamoto, Masatoshi [LABOTEC Co. Ltd., 4-15-48 Itsukaiti, Saeki-ku, Hiroshima 731-5128 (Japan); Kikkawa, Megumi [LABOTEC Co. Ltd., 4-15-48 Itsukaiti, Saeki-ku, Hiroshima 731-5128 (Japan); Sakugawa, Hiroshi [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan)

    2007-01-09

    Photoformation rates and scavenging rate constants of hydroxyl radicals ({center_dot}OH) in natural water samples were determined by an automatic determination system. After addition of benzene as a chemical probe to a water sample in a reaction cell, light irradiation and injection of irradiated water samples into an HPLC as a function of time were performed automatically. Phenol produced by the reaction between {center_dot}OH and the benzene added to the water sample was determined to quantify the {center_dot}OH formation rate. The rate constants of {center_dot}OH formation from the photolysis of nitrate ions, nitrite ions and hydrogen peroxide were comparable with those obtained in previous studies. The percent of expected {center_dot}OH photoformation rate from added nitrate ion were high in drinking water (97.4%) and river water (99.3%). On the other hand, the low percent (65.0%) was observed in seawater due to the reaction of {center_dot}OH with the high concentrations of chloride and bromide ions. For the automatic system, the coefficient of variance for the determination of the {center_dot}OH formation rate was less than 5.0%, which is smaller than that in the previous report. When the complete time sequence of analytical cycle was 40 min for one sample, the detection limit of the photoformation rate and the sample throughput were 8 x 10{sup -13} M s{sup -1} and 20 samples per day, respectively. The automatic system successfully determined the photoformation rates and scavenging rate constants of {center_dot}OH in commercial drinking water and the major source and sink of {center_dot}OH were identified as nitrate and bicarbonate ions, respectively.

  4. A dynamic compensation method for natural ambient dose rate based on 6 years data from the Dutch radioactivity monitoring network

    International Nuclear Information System (INIS)

    Smetsers, R.C.G.M.; Blaauboer, R.O.

    1997-01-01

    The significant variations in time exhibited by background radiation hinders a sensitive recognition of human-induced factors. A comprehensive study in the Netherlands has examined the influence of the various natural processes on the natural background using six years data from the Dutch nuclear emergency network. Results presented concentrate on temporal variations in ambient dose-equivalent rate, H*(10), and have led to simple expressions to model the ambient dose rate using a limited set of readily available parameters, i.e. air pressure, deposition rate and equilibrium equivalent decay product concentration of 222 Rn, EEDC. Best values and uncertainty ranges of the applied parameters are reported. Remaining variations, e.g. due to variations in the cosmic radiation intensity and the radon soil profile, are shown to be small in the Netherlands, with one exception when the cosmogenic dose rate at sea level was decreased for a period of months due to a global deflection of the earth's magnetic field in the summer of 1991. The resulting compensation method for the natural ambient dose rate enables sensitive detection of anomalies, supporting the surveillance of nuclear installations and the management of nuclear emergency networks. (Author)

  5. The nature and structure of correlations among Big Five ratings: the halo-alpha-beta model.

    Science.gov (United States)

    Anusic, Ivana; Schimmack, Ulrich; Pinkus, Rebecca T; Lockwood, Penelope

    2009-12-01

    In light of consistently observed correlations among Big Five ratings, the authors developed and tested a model that combined E. L. Thorndike's (1920) general evaluative bias (halo) model and J. M. Digman's (1997) higher order personality factors (alpha and beta) model. With 4 multitrait-multimethod analyses, Study 1 revealed moderate convergent validity for alpha and beta across raters, whereas halo was mainly a unique factor for each rater. In Study 2, the authors showed that the halo factor was highly correlated with a validated measure of evaluative biases in self-ratings. Study 3 showed that halo is more strongly correlated with self-ratings of self-esteem than self-ratings of the Big Five, which suggests that halo is not a mere rating bias but actually reflects overly positive self-evaluations. Finally, Study 4 demonstrated that the halo bias in Big Five ratings is stable over short retest intervals. Taken together, the results suggest that the halo-alpha-beta model integrates the main findings in structural analyses of Big Five correlations. Accordingly, halo bias in self-ratings is a reliable and stable bias in individuals' perceptions of their own attributes. Implications of the present findings for the assessment of Big Five personality traits in monomethod studies are discussed.

  6. Potential increases in natural disturbance rates could offset forest management impacts on ecosystem carbon stocks.

    Science.gov (United States)

    John B. Bradford; Nicholas R. Jensen; Grant M. Domke; Anthony W. D' Amato

    2013-01-01

    Forested ecosystems contain the majority of the world’s terrestrial carbon, and forest management has implications for regional and global carbon cycling. Carbon stored in forests changes with stand age and is affected by natural disturbance and timber harvesting. We examined how harvesting and disturbance interact to influence forest carbon stocks over the Superior...

  7. "Depletion": A Game with Natural Rules for Teaching Reaction Rate Theory.

    Science.gov (United States)

    Olbris, Donald J.; Herzfeld, Judith

    2002-01-01

    Depletion is a game that reinforces central concepts of reaction rate theory through simulation. Presents the game with a set of follow-up questions suitable for either a quiz or discussion. Also describes student reaction to the game. (MM)

  8. 99Tc(VII) Retardation, Reduction, and Redox Rate Scaling in Naturally Reduced Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuanyuan; Liu, Chongxuan; Kukkadapu, Ravi K.; McKinley, James P.; Zachara, John M.; Plymale, Andrew E.; Miller, Micah D.; Varga, Tamas; Resch, Charles T.

    2015-10-15

    Abstract: An experimental and modeling study was conducted to investigate pertechnetate (Tc(VII)) retardation, reduction, and rate scaling in three sediments from Ringold formation at U.S. Department of Energy’s Hanford site, where 99Tc is a major contaminant in groundwater. Tc(VII) was reduced in all the sediments in both batch reactors and diffusion columns, with a faster rate in a sediment containing a higher concentration of HCl-extractable Fe(II). Tc(VII) migration in the diffusion columns was reductively retarded with retardation degrees correlated with Tc(VII) reduction rates. The reduction rates were faster in the diffusion columns than those in the batch reactors, apparently influenced by the spatial distribution of redox-reactive minerals along transport paths that supplied Tc(VII). X-ray computed tomography and autoradiography were performed to identify the spatial locations of Tc(VII) reduction and transport paths in the sediments, and results generally confirmed the newly found behavior of reaction rate changes from batch to column. The results from this study implied that Tc(VII) migration can be reductively retarded at Hanford site with a retardation degree dependent on reactive Fe(II) content and its distribution in sediments. This study also demonstrated that an effective reaction rate may be faster in transport systems than that in well-mixed reactors.

  9. Wind dependence on the flow rate in a natural draught cooling tower

    International Nuclear Information System (INIS)

    Baer, E.; Ernst, G.; Wurz, D.

    1981-01-01

    The efficiency of a natural draught cooling tower depends, among other things, on the effect of the wind on the flow in the tower stack. Determinations were made on a natural draught wet cooling tower 100 metres high, for the purpose of studying this effects. As characteristic quantity, a typical height was determined, the values of which were worked out from the results of the measurements. The efficiency of the stack is affected the most in the case of average wind velocities (when the velocity of the wind is about equal to the mean velocity of the plume). This effect diminishes when the velocity of the wind increases. In the case of average wind velocities, the direction of the wind has an effect, owing to the neighbouring buildings; for slightly greater wind velocities, no effect could be found [fr

  10. DEVELOPMENT OF A LOW-COST INFERENTIAL NATURAL GAS ENERGY FLOW RATE PROTOTYPE RETROFIT MODULE

    Energy Technology Data Exchange (ETDEWEB)

    E. Kelner; T.E. Owen; D.L. George; A. Minachi; M.G. Nored; C.J. Schwartz

    2004-03-01

    In 1998, Southwest Research Institute{reg_sign} began a multi-year project co-funded by the Gas Research Institute (GRI) and the U.S. Department of Energy. The project goal is to develop a working prototype instrument module for natural gas energy measurement. The module will be used to retrofit a natural gas custody transfer flow meter for energy measurement, at a cost an order of magnitude lower than a gas chromatograph. Development and evaluation of the prototype retrofit natural gas energy flow meter in 2000-2001 included: (1) evaluation of the inferential gas energy analysis algorithm using supplemental gas databases and anticipated worst-case gas mixtures; (2) identification and feasibility review of potential sensing technologies for nitrogen diluent content; (3) experimental performance evaluation of infrared absorption sensors for carbon dioxide diluent content; and (4) procurement of a custom ultrasonic transducer and redesign of the ultrasonic pulse reflection correlation sensor for precision speed-of-sound measurements. A prototype energy meter module containing improved carbon dioxide and speed-of-sound sensors was constructed and tested in the GRI Metering Research Facility at SwRI. Performance of this module using transmission-quality natural gas and gas containing supplemental carbon dioxide up to 9 mol% resulted in gas energy determinations well within the inferential algorithm worst-case tolerance of {+-}2.4 Btu/scf (nitrogen diluent gas measured by gas chromatograph). A two-week field test was performed at a gas-fired power plant to evaluate the inferential algorithm and the data acquisition requirements needed to adapt the prototype energy meter module to practical field site conditions.

  11. National survey on the natural radioactivity and 222Rn exhalation rate of building materials in The Netherlands.

    Science.gov (United States)

    de Jong, P; van Dijk, W; van der Graaf, E R; de Groot, T J H

    2006-09-01

    The present study reports on results of a nation-wide survey on the natural radioactivity concentrations and Rn exhalation rates of the prevailing building materials in the Netherlands. In total 100 samples were taken and analyzed for the activity concentrations of Ra, Ra, Th, and K and for their Rn exhalation rate. The sampled materials consisted of gypsum products, aerated concrete, sand-lime and clay bricks, mortars and concrete, representing about 95% of the stony building materials used in the construction of Dutch homes. The laboratory analyses were performed according to two well-documented standard procedures, the interlaboratory reproducibility of which is found to be within 5% on average. The highest radionuclide concentrations were found in a porous inner wall brick to which fly ash was added. The second highest were clay bricks with average Ra and Ra levels around 40 Bq kg. Concrete and mortar show the highest exhalation rates with a fairly broad range of 1 to 13 microBq (kg s). Low natural radioactivity levels are associated with either natural gypsum (products) or gypsum from flue gas desulphurization units, and low exhalation rates with clay bricks. To evaluate the radiological impact the radioactivity concentrations in each sample were combined into a so-called dose factor, representing the absorbed dose rate in a room with a floor, walls and ceiling of 20 cm of the material in question. For that purpose, calculations with the computer codes MCNP, Marmer and MicroShield on the specific absorbed dose rates were incorporated in the paper. The results of these codes corresponded within 6% and average values were calculated at 0.90, 1.10, and 0.080 nGy h per Bq kg for the U series, the Th series, and K, respectively. Model calculations on the external dose rate, based on the incidence of the various building materials in 1,336 living rooms, are in accordance with measured data.

  12. Pretreatment Acoustic Predictors of Gender, Femininity, and Naturalness Ratings in Individuals With Male-to-Female Gender Identity.

    Science.gov (United States)

    Hardy, Teresa L D; Boliek, Carol A; Wells, Kristopher; Dearden, Carol; Zalmanowitz, Connie; Rieger, Jana M

    2016-05-01

    The purpose of this study was to describe the pretreatment acoustic characteristics of individuals with male-to-female gender identity (IMtFGI) and investigate the ability of the acoustic measures to predict ratings of gender, femininity, and vocal naturalness. This retrospective descriptive study included 2 groups of participants. Speakers were IMtFGI who had not previously received communication feminization treatment (N = 25). Listeners were members of the lay community (N = 30). Acoustic data were retrospectively obtained from pretreatment recordings, and pretreatment recordings also served as stimuli for 3 perceptual rating tasks (completed by listeners). Acoustic data generally were within normal limits for male speakers. All but 2 speakers were perceived to be male, limiting information about the relationship between acoustic measures and gender perception. Fundamental frequency (reading) significantly predicted femininity ratings (p = .000). A total of 3 stepwise regression models indicated that minimum frequency (range task), second vowel formant (sustained vowel), and shimmer percentage (sustained vowel) together significantly predicted naturalness ratings (p = .005, p = .003, and p = .002, respectively). Study aims were achieved with the exception of acoustic predictors of gender perception, which could be described for only 2 speakers. Future research should investigate measures of prosody, voice quality, and other aspects of communication as predictors of gender, femininity, and naturalness.

  13. Effects of the anion salt nature on the rate constants of the aqueous proton exchange reactions.

    Science.gov (United States)

    Paredes, Jose M; Garzon, Andres; Crovetto, Luis; Orte, Angel; Lopez, Sergio G; Alvarez-Pez, Jose M

    2012-04-28

    The proton-transfer ground-state rate constants of the xanthenic dye 9-[1-(2-methyl-4-methoxyphenyl)]-6-hydroxy-3H-xanthen-3-one (TG-II), recovered by Fluorescence Lifetime Correlation Spectroscopy (FLCS), have proven to be useful to quantitatively reflect specific cation effects in aqueous solutions (J. M. Paredes, L. Crovetto, A. Orte, J. M. Alvarez-Pez and E. M. Talavera, Phys. Chem. Chem. Phys., 2011, 13, 1685-1694). Since these phenomena are more sensitive to anions than to cations, in this paper we have accounted for the influence of salts with the sodium cation in common, and the anion classified according to the empirical Hofmeister series, on the proton transfer rate constants of TG-II. We demonstrate that the presence of ions accelerates the rate of the ground-state proton-exchange reaction in the same order than ions that affect ion solvation in water. The combination of FLCS with a fluorophore undergoing proton transfer reactions in the ground state, along with the desirable feature of a pseudo-dark state when the dye is protonated, allows one unique direct determination of kinetic rate constants of the proton exchange chemical reaction. This journal is © the Owner Societies 2012

  14. New rate structure of the Dutch natural gas trading company Gasunie

    International Nuclear Information System (INIS)

    Koevoet, H.

    1999-01-01

    Starting January 1, 2000, many of Gasunie's large-scale consumers will have to deal with a new rate structure: the CDS (Dutch abbreviation for Commodity Services System). Unlike in the old zone system, the consumption profile is of great importance in the CDS. Those who must heat large spaces have a particular interest in sizing up the consequences of the CDS

  15. Avian basal metabolic rates : their association with body composition and energy expenditure in nature

    NARCIS (Netherlands)

    Daan, Serge; Masman, Dirkjan; Groenewold, Alex

    Measurements of basal metabolic rate (BMR), body water, fat, and lean dry mass of different organs were obtained in 22 bird species, ranging from 10.8 to 1,253 g body mass. Residuals of BMR (after subtracting BMR allometrically predicted from body mass) were positively correlated with residuals of

  16. Flavonoids Released Naturally from Alfalfa Seeds Enhance Growth Rate of Rhizobium meliloti1

    Science.gov (United States)

    Hartwig, Ueli A.; Joseph, Cecillia M.; Phillips, Donald A.

    1991-01-01

    Alfalfa (Medicago sativa L.) releases different flavonoids from seeds and roots. Imbibing seeds discharge 3′,4′,5,7-substituted flavonoids; roots exude 5-deoxy molecules. Many, but not all, of these flavonoids induce nodulation (nod) genes in Rhizobium meliloti. The dominant flavonoid released from alfalfa seeds is identified here as quercetin-3-O-galactoside, a molecule that does not induce nod genes. Low concentrations (1-10 micromolar) of this compound, as well as luteolin-7-O-glucoside, another major flavonoid released from germinating seeds, and the aglycones, quercetin and luteolin, increase growth rate of R. meliloti in a defined minimal medium. Tests show that the 5,7-dihydroxyl substitution pattern on those molecules was primarily responsible for the growth effect, thus explaining how 5-deoxy flavonoids in root exudates fail to enhance growth of R. meliloti. Luteolin increases growth by a mechanism separate from its capacity to induce rhizobial nod genes, because it still enhanced growth rate of R. meliloti lacking functional copies of the three known nodD genes. Quercetin and luteolin also increased growth rate of Pseudomonas putida. They had no effect on growth rate of Bacillus subtilis or Agrobacterium tumefaciens, but they slowed growth of two fungal pathogens of alfalfa. These results suggest that alfalfa can create ecochemical zones for controlling soil microbes by releasing structurally different flavonoids from seeds and roots. PMID:16668056

  17. DEVELOPMENT OF A LOW COST INFERENTIAL NATURAL GAS ENERGY FLOW RATE PROTOTYPE RETROFIT MODULE

    Energy Technology Data Exchange (ETDEWEB)

    E. Kelner; D. George; T. Morrow; T. Owen; M. Nored; R. Burkey; A. Minachi

    2005-05-01

    In 1998, Southwest Research Institute began a multi-year project to develop a working prototype instrument module for natural gas energy measurement. The module will be used to retrofit a natural gas custody transfer flow meter for energy measurement, at a cost an order of magnitude lower than a gas chromatograph. Development and evaluation of the prototype energy meter in 2002-2003 included: (1) refinement of the algorithm used to infer properties of the natural gas stream, such as heating value; (2) evaluation of potential sensing technologies for nitrogen content, improvements in carbon dioxide measurements, and improvements in ultrasonic measurement technology and signal processing for improved speed of sound measurements; (3) design, fabrication and testing of a new prototype energy meter module incorporating these algorithm and sensor refinements; and (4) laboratory and field performance tests of the original and modified energy meter modules. Field tests of the original energy meter module have provided results in close agreement with an onsite gas chromatograph. The original algorithm has also been tested at a field site as a stand-alone application using measurements from in situ instruments, and has demonstrated its usefulness as a diagnostic tool. The algorithm has been revised to use measurement technologies existing in the module to measure the gas stream at multiple states and infer nitrogen content. The instrumentation module has also been modified to incorporate recent improvements in CO{sub 2} and sound speed sensing technology. Laboratory testing of the upgraded module has identified additional testing needed to attain the target accuracy in sound speed measurements and heating value.

  18. Experimental Investigation of a Natural Circulation Solar Domestic Water Heater Performance under Standard Consumption Rate

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Taherian, H.; Ganji, D. D.

    2012-01-01

    This paper reports experimental studies on the performance of a natural circulation solar water heater considering the weather condition of a city in north of Iran. The tests are done on clear and partly cloudy days. The variations of storage tank temperature due to consumption from the tank, daily...... consumption influence on the solar water heater efficiency, and on the input temperature of the collector are studied and the delivered daily useful energy has been obtained. The results show that by withdrawing from storage tank, the system as well as its collector efficiency will increase. Considering...

  19. Estimation of 99Mo production rates from natural molybdenum in research reactors

    International Nuclear Information System (INIS)

    Blaauw, M.; Chakrova, Y.; Jacimovic, R.; Kling, A.

    2017-01-01

    Molybdenum-99 is one of the most important radionuclides for medical diagnostics. In 2015, the International Atomic Energy Agency organized a round-robin exercise where the participants measured and calculated specific saturation activities achievable for the 98 Mo(n,γ) 99 Mo reaction. This reaction is of interest as a means to locally, and on a small scale, produce 99 Mo from natural molybdenum. The current paper summarises a set of experimental results and reviews the methodology for calculating the corresponding saturation activities. Activation by epithermal neutrons and also epithermal neutron self-shielding are found to be of high importance in this case. (author)

  20. Growth rate of diatoms in natural environment from the coastal waters of pakistan

    International Nuclear Information System (INIS)

    Naz, T.; Burhan, Z.U.N.; Munir, S.; Siddiqui, P.J.A.

    2014-01-01

    Growth rate of diatoms were analyzed by 24 hours in situ incubation technique at coastal waters of Karachi, Pakistan (northern Arabian Sea). Sampling was done at two stations, station A located inside the channel and station B outside the channel during February, 2006 and at the mouth of the channel during May, 2007. The diatom species dominated in the community were Nitzschia closterium, Nitzschia logissima, Pleurosigma spp and Thalassiosira sp. Total community growth rate was negative -0.11d-1 in summer and -0.7 d-1 at station B but positive 0.1d-1 at station A in winter. The individual species have given positive response of growth even in the presence of grazers. During the summer months the differences observed from the winter months may have been due to differences in microzooplankton composition. Heterotrophic dinoflagellates have a large impact on the growth rates. Since these dinoflagellates feed on the large diatoms, it suggests that this is a major factor determine the growth rate of diatoms. Total diatom abundance at initial T0 and final T24 incubation periods coincided with the chlorophyll a values at station B in winter and summer seasons, but they did not display similar pattern at station A, suggesting that when the large grazers removed from the sample through prescreening the diatom growth increased. Presence of high concentration of nutrients near the coast could be one of the reasons of high growth rate at station A as compared to station B which was near off shore. (author)

  1. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  2. Pregnancy rate in Bulgarian White milk goats with natural and synchronized estrus after artificial insemination by frozen semen during breeding season

    Directory of Open Access Journals (Sweden)

    Stanimir A. Yotov

    2016-04-01

    Conclusion: The goats with natural estrus and GnRH treatment tend to enhance pregnancy rate after double artificial insemination 8 h apart. The insemination number has no significant impact on pregnancy rate in synchronized goats as the overall pregnancy rate is better than in animals with natural estrus without GnRH administration.

  3. Removal Rate of Organic Matter Using Natural Cellulose via Adsorption Isotherm and Kinetic Studies.

    Science.gov (United States)

    Din, Mohd Fadhil Md; Ponraj, Mohanadoss; Low, Wen-Pei; Fulazzaky, Mohamad Ali; Iwao, Kenzo; Songip, Ahmad Rahman; Chelliapan, Shreeshivadasan; Ismail, Zulhilmi; Jamal, Mohamad Hidayat

    2016-02-01

    In this study, the removal of natural organic matter (NOM) using coconut fiber (CF) and palm oil fiber (POF) was investigated. Preliminary analysis was performed using a jar test for the selection of optimal medium before the fabricated column model experiment. The equilibrium studies on isotherms and kinetic models for NOM adsorption were analyzed using linearized correlation coefficient. Results showed that the equilibrium data were fitted to Langmuir isotherm model for both CF and POF. The most suitable adsorption model was the pseudo-first-order kinetic model for POF and pseudo-second-order kinetic model for CF. The adsorption capacities achieved by the CF and POF were 15.67 and 30.8 mg/g respectively. Based on this investigation, it can be concluded that the POF is the most suitable material for the removal of NOM in semi polluted river water.

  4. Effect of natural fiber types and sodium silicate coated on natural fiber mat/PLA composites: Tensile properties and rate of fire propagation

    Science.gov (United States)

    Thongpin, C.; Srimuk, J.; hipkam, N.; Wachirapong, P.

    2015-07-01

    In this study, 3 types of natural fibres, i.e. jute, sisal and abaca, were plain weaved to fibre mat. Before weaving, the fibres were treated with 5% NaOH to remove hemi cellulose and lignin. The weaving was performed by hand using square wooden block fit with nails for weaving using one and two types of natural fibres as weft and warp fibre to produce natural fibre mat. The fibre mat was also impregnated in sodium silicate solution extracted from rich husk ash. The pH of the solution was adjusted to pH 7 using H2SO4 before impregnation. After predetermined time, sodium silicate was gelled and deposited on the mat. The fabric mat and sodium silicate coated mat were then impregnated with PLA solution to produce prepreg. Dried pepreg was laminated with PLA sheet using compressing moulding machine to obtain natural fibre mat/PLA composite. The composite containing abaca aligned in longitudinal direction with respect to tension force enhanced Young's modulus more than 300%. Fibre mat composites with abaca aligned in longitudinal direction also showed tensile strength enhancement nearly 400% higher than neat PLA. After coating with sodium silicate, the tensile modulus of the composites was found slightly increased. The silicate coating was disadvantage on tensile strength of the composite due to the effect of sodium hydroxide solution that was used as solvent for silicate extraction from rice husk ash. However, sodium silicate could retard rate of fire propagation about 50%compare to neat PLA and about 10% reduction compared to fibre mat composites without sodium silicate coated fibre mat.

  5. Estimation of radon exhalation rate, natural radioactivity and radiation doses in fly ash samples from NTPC Dadri, (UP) India

    International Nuclear Information System (INIS)

    Gupta, Mamta; Verma, K.D.; Mahur, A.K.; Rajendra Prasad; Sonkawade, R.G.

    2010-01-01

    Fly ash produced by coal-burning in thermal power station has become a subject of world wide interest in recent years, because of its diverse uses in building materials such as bricks, sheets, cement and land filling etc. The knowledge of radio nuclides in fly ash plays an important role in health physics. Natural radioactivity and radon exhalation rate in fly ash samples collected from NTPC (National Thermal Power Corporation) Dadri, (UP.) India, have been studied. A high resolution gamma ray spectroscopic system has been used for the measurement of natural radioactivity. The activity concentration of natural radionuclides radium ( 226 Ra), thorium ( 232 Th) and potassium ( 40 K) were measured and radiological parameters were calculated. Radium concentration was found to vary from (81.01 ± 3.25) to (177.33 ±10.00) Bq kg -1 . Activity concentration of thorium was found to vary from (111.57 ± 3.21) to (178.50 ± 3.96) Bq kg -1 . Potassium activity was not significant in some samples, whereas, some other samples have shown potassium activity vary from (365.98 ± 4.85) to (495.95 ± 6.23) Bq kg -1 . Radon exhalation rates in these samples were also calculated by 'Sealed Can technique' using LR-115 type II detectors and found to vary from (80 ± 9) to (243 ± 16) mBqm -2 h -1 with an average value (155 ± 13) mBqm -2 h -1 . This study also presents the results of estimation of effective dose equivalent from exhalation rate, radium equivalent, absorbed gamma dose rates, external annual effective dose rate and values of external hazard index for the fly ash samples. (author)

  6. Mercury's Hollows: Depths, Estimation of Formation Rates, and the Nature of the Bright Haloes

    Science.gov (United States)

    Blewett, D. T.; Stadermann, A. C.; Chabot, N. L.; Denevi, B. W.; Ernst, C. M.; Xiao, Z.; Solomon, S. C.

    2015-12-01

    Mercury's hollows are shallow depressions, often with high-reflectance interiors and haloes. The fresh appearance of hollows indicates that they are relatively young features. Their morphology is suggestive of formation via sublimation-like loss of a volatile-bearing phase through solar heating, destruction by UV photolysis, contact with molten rock, or bombardment by micrometeoroids and/or ions. Hollows are found within the low-reflectance material (LRM) color unit. Following an examination of all MESSENGER images with pixel sizes hollows. The mean depth is 24 ± 16 m. The narrow range of depths, despite formation within LRM units that are of much greater and more variable thickness, could result from development of a protective lag as the volatile-bearing phase is lost. The rate at which hollows form may be estimated as follows. The size-frequency distribution of Mercury rayed craters >4 km in diameter gives absolute model ages of 110 to 689 Ma, depending on the crater production model. The 41-km-diameter rayed crater Balanchine has a density of superposed craters similar to the average for all rayed craters, so we take Balanchine's age to be the population average. Hollows on Balanchine's floor are ~300 m wide. The average rate of hollows formation by horizontal scarp retreat for a 110 Ma model age would be 1 cm per 3700 Earth years. If Balanchine formed 689 Ma ago, then the average growth rate would be 1 cm per 23,000 yr. We also consider the mechanisms by which hollows form bright haloes. Calculations show that comet-style lofting of dust by sublimating gas is not important given Mercury's high surface gravitational acceleration. Instead, the bright haloes may form by condensation of sublimated material or by physical modification or chemical alteration of the surface by re-deposited sublimation products.

  7. Towards Understanding and Managing Sustainable Complex, Dynamic Environmental/Economic/Social Systems - The Evolving Role of the Natural Sciences

    Science.gov (United States)

    Historically the natural sciences have played a major role in informing environmental management decisions. However, review of landmark cases like Love Canal, NY and Times Beach, MO have shown that the value of natural science information in decision making can be overwhelmed by ...

  8. A Science Faculty's Transformation of Nature of Science Understanding into His Teaching Graduate Level Chemistry Course

    Science.gov (United States)

    Aydin, Sevgi

    2015-01-01

    This is an interpretive case study to examine the teaching of an experienced science faculty who had a strong interest in teaching undergraduate and graduate science courses and nature of science specifically. It was interested in how he transformed knowledge from his experience as a scientist and his ideas about nature of science into forms…

  9. Effect of artificial and natural phospholipid membranes on rate of sperm whale oxymyoglobin autooxidation.

    Science.gov (United States)

    Postnikova, G B; Shekhovtsova, E A

    2013-03-01

    We were the first to show that MbO2 deoxygenation in the cell occurs only upon interaction of myoglobin with mitochondrial membrane, which must be accompanied by changes in the heme cavity conformation of the protein and its affinity for the ligand. Under aerobic conditions, some changes in the equilibrium O2 dissociation constant (Kdis) can be detected by changes of the rate of MbO2 autooxidation, i.e. spontaneous turning it into metMb (kox), as far as a direct correlation between Kdis and kox is experimentally shown. In this work, we studied the effect on MbO2 autooxidation rate of phospholipid liposomes from neutral soybean phosphatidylcholine (lecithin) and from negatively charged 1-palmitoyl-2-oleylphosphatidylglycerol (POPG) at various phospholipid/MbO2 ratios from 25 : 1 to 100 : 1, and also the effect of rat liver mitochondria at concentration of 1 and 2 mg/ml mitochondrial protein (at 22 and 37°C). In all cases, kox was found to increase due to interaction of the protein with phospholipid membranes. The effect of negatively charged liposomes from POPG on kox is significantly greater than that of neutral lecithin liposomes. At the POPG/MbO2 molar ratio of 25 : 1, MbO2 autooxidation rate is almost 25-fold increased compared to the control, whereas in the presence of 50-fold molar excess of lecithin, kox is only ~10 times higher (10 mM buffer, pH 7.2, 22°C). With the same phospholipid/MbO2 ratio of 100 : 1, kox is 7 times higher for the POPG than for lecithin liposomes. In the presence of mitochondria inhibited by antimycin A, kox grows proportionally to their concentration (about 10-fold per 1 mg/ml of mitochondrial protein), and practically does not change after adding superoxide dismutase in the reaction mixture. The kox value decreases markedly at high ionic strength, thus suggesting an important role of coulombic electrostatics in the myoglobin-mitochondrial interaction. The increase in the autooxidation rate of MbO2 (and hence its Kdis) due to the

  10. Rate of translation of natural mRNAs in an optimized in vitro system.

    Science.gov (United States)

    Pavlov, M Y; Ehrenberg, M

    1996-04-01

    We report results on in vitro translation of an mRNA coding for elongation factor TuB which was in vitro transcribed from the tufB gene from Escherichia coli. Translation occurs at a rate of about 10 codons per second, which is close to the in vivo rate. Protein elongation obeys Michaelis-Menten kinetics with respect to the concentrations of the elongation factors EF-Tu and EF-G in the translation system. The measured K(m) values for EF-Tu and EF-G are 10 and 0.25 microM, respectively. The obtained k(cat) and K(m) values were used to estimate the average k(cat)/K(m) of about 24 x 10(6) s-1 M-1 for the interaction of individual EF-Tu*GTP*aa-tRNA complexes with ribosomes. The estimated k(cat)/K(m) value for EF-G is 36 x 10(6) s-1 M-1. We have also studied translation with a "hyperaccurate" ribosome variant that is pseudodependent on streptomycin (SmP). We have found that SmP ribosomes translate the TuB mRNA significantly slower than wild-type ribosomes do. This is mainly due to a threefold lower k(cat)/K(m) for the interaction of EF-Tu*GTP*aa-tRNA complexes with SmP ribosomes.

  11. Debt Relief of Natural Persons and the Rate of Satisfaction of Their Creditors in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Marie Pasekova

    2015-06-01

    Full Text Available The purpose of this contribution is to ascertain the rate of creditors’ satisfaction in debt relief. The aim of the paper is to set an approximation functions which guarantee a value of 100% of satisfaction of creditors’ receivables for a zero rate of debt and asymptotically nears a level of 30% with an increasing rate of debt. There are two methods used in this paper. Method of analysis was used to analyse of collected data on the course of debt relief of natural person. The method of the ordinary least squares method was used for setting the approximation functions. On the basis of a survey, it was found that individual creditors are satisfied to 50% of their ascertained receivables.

  12. Survey of Gamma Dose and Radon Exhalation Rate from Soil Surface of High Background Natural Radiation Areas in Ramsar, Iran

    Directory of Open Access Journals (Sweden)

    Rouhollah Dehghani

    2013-09-01

    Full Text Available Background: Radon is a radioactive gas and the second leading cause of death due to lung cancer after smoking. Ramsar is known for having the highest levels of natural background radiation on earth. Materials and Methods: In this research study, 50 stations of high radioactivity areas of Ramsar were selected in warm season of the year. Then gamma dose and radon exhalation rate were measured.Results: Results showed that gamma dose and radon exhalation rate were in the range of 51-7100 nSv/hr and 9-15370 mBq/m2s, respectively.Conclusion: Compare to the worldwide average 16 mBq/m2s, estimated average annual effective of Radon exhalation rate in the study area is too high.

  13. Understandings of the 'natural' body: a comparison of the views of users and providers of emergency contraception.

    Science.gov (United States)

    Keogh, L A

    2005-01-01

    'Natural' is a pervasive discourse with mixed meanings in contemporary society. I was interested in how users and providers of emergency contraception conceptualised the 'natural' body in contraceptive decision making. Thirty-two users and 19 providers of emergency contraception from three sites in metropolitan Melbourne were interviewed, or participated in focus groups, about emergency contraceptive use, contraceptive decision making and perceptions of risk. The qualitative data were transcribed and coded to identify the key ways that both users and providers perceived the 'natural' body. Providers and users adopted different frameworks for interpreting the discourse of the 'natural' body. Thirteen of the 32 users identified the 'natural' body as a factor in their decision making. They identified a 'natural' body as a body experiencing no interruption with ovulation, and/or free from unwanted side effects. Six of the 13 women who discussed the 'natural' body used a contraceptive that allowed them to preserve their natural body (e.g. condoms). The remaining seven women identified it as an ideal that they could not achieve. Providers in general discredited the idea of a 'natural' body and instead conceptualised contraceptive decision making as a 'simple' risk-benefit analysis. The differences between the two groups can be understood in a number of different ways. The important conclusion however, is that the different perspectives present a potential barrier to effective communication in the contraceptive consultation, and may be able to be resolved through the development of an embodied risk-benefit analysis that may be meaningful to both groups.

  14. The Rate and Spectrum of Spontaneous Mutations in Mycobacterium smegmatis, a Bacterium Naturally Devoid of the Postreplicative Mismatch Repair Pathway

    Directory of Open Access Journals (Sweden)

    Sibel Kucukyildirim

    2016-07-01

    Full Text Available Mycobacterium smegmatis is a bacterium that is naturally devoid of known postreplicative DNA mismatch repair (MMR homologs, mutS and mutL, providing an opportunity to investigate how the mutation rate and spectrum has evolved in the absence of a highly conserved primary repair pathway. Mutation accumulation experiments of M. smegmatis yielded a base-substitution mutation rate of 5.27 × 10−10 per site per generation, or 0.0036 per genome per generation, which is surprisingly similar to the mutation rate in MMR-functional unicellular organisms. Transitions were found more frequently than transversions, with the A:T→G:C transition rate significantly higher than the G:C→A:T transition rate, opposite to what is observed in most studied bacteria. We also found that the transition-mutation rate of M. smegmatis is significantly lower than that of other naturally MMR-devoid or MMR-knockout organisms. Two possible candidates that could be responsible for maintaining high DNA fidelity in this MMR-deficient organism are the ancestral-like DNA polymerase DnaE1, which contains a highly efficient DNA proofreading histidinol phosphatase (PHP domain, and/or the existence of a uracil-DNA glycosylase B (UdgB homolog that might protect the GC-rich M. smegmatis genome against DNA damage arising from oxidation or deamination. Our results suggest that M. smegmatis has a noncanonical Dam (DNA adenine methylase methylation system, with target motifs differing from those previously reported. The mutation features of M. smegmatis provide further evidence that genomes harbor alternative routes for improving replication fidelity, even in the absence of major repair pathways.

  15. The Rate and Spectrum of Spontaneous Mutations in Mycobacterium smegmatis, a Bacterium Naturally Devoid of the Postreplicative Mismatch Repair Pathway.

    Science.gov (United States)

    Kucukyildirim, Sibel; Long, Hongan; Sung, Way; Miller, Samuel F; Doak, Thomas G; Lynch, Michael

    2016-07-07

    Mycobacterium smegmatis is a bacterium that is naturally devoid of known postreplicative DNA mismatch repair (MMR) homologs, mutS and mutL, providing an opportunity to investigate how the mutation rate and spectrum has evolved in the absence of a highly conserved primary repair pathway. Mutation accumulation experiments of M. smegmatis yielded a base-substitution mutation rate of 5.27 × 10(-10) per site per generation, or 0.0036 per genome per generation, which is surprisingly similar to the mutation rate in MMR-functional unicellular organisms. Transitions were found more frequently than transversions, with the A:T→G:C transition rate significantly higher than the G:C→A:T transition rate, opposite to what is observed in most studied bacteria. We also found that the transition-mutation rate of M. smegmatis is significantly lower than that of other naturally MMR-devoid or MMR-knockout organisms. Two possible candidates that could be responsible for maintaining high DNA fidelity in this MMR-deficient organism are the ancestral-like DNA polymerase DnaE1, which contains a highly efficient DNA proofreading histidinol phosphatase (PHP) domain, and/or the existence of a uracil-DNA glycosylase B (UdgB) homolog that might protect the GC-rich M. smegmatis genome against DNA damage arising from oxidation or deamination. Our results suggest that M. smegmatis has a noncanonical Dam (DNA adenine methylase) methylation system, with target motifs differing from those previously reported. The mutation features of M. smegmatis provide further evidence that genomes harbor alternative routes for improving replication fidelity, even in the absence of major repair pathways. Copyright © 2016 Kucukyildirim et al.

  16. Rates and patterns of plankton response to stress exposure under natural conditions

    Science.gov (United States)

    Kucera, M.; Weinkauf, M.

    2016-02-01

    The effects of long-term exposure to natural levels of stress are often difficult to assess directly, because the resulting physiological changes and adaptations occur over times scales that cannot be covered by observations and where the outcome of the exposure cannot be predicted. Biometric studies on fossils provide a unique opportunity bridge this time scale and provide information on the reaction of populations to different levels of stress, including stress leading to extinction. In this respect, planktonic foraminifera represent a suitable model organism. This is because their shells, which are well preserved in marine sediments, record their entire ontogeny and allow assessment of developmental stability. Here we studied fossil populations of planktonic foraminifera transitioning into a high-stress environment during the onset of the deposition of Sapropel S5 in the Eastern Mediterranean, which culminated in local extinctions of several species. We show that calcification intensity (i.e. the amount of calcite secreted for a given body size) showed a strong and rapid reaction to surface water perturbation, with the same direction of change all species but no change prior to extinction, indicating that this parameters is primarily under environmental control. In contrast, shell morphology was not strictly tied to environmental change, but we observed large and rapid deviations in developmental stability immediately preceding local extinctions. It seems that developmental stability throughout ontogeny can be disrupted by enhanced stress levels leading to increased variation. This mechanism seems to operate on very short (decadal) time scales. It can potentially play a role in microevolution, and may be useful as an environmental stress proxy in plankton communities.

  17. Modeling the Interrelationships among Pre-Service Science Teachers' Understanding and Acceptance of Evolution, Their Views on Nature of Science and Self-Efficacy Beliefs regarding Teaching Evolution

    Science.gov (United States)

    Akyol, Gulsum; Tekkaya, Ceren; Sungur, Semra; Traynor, Anne

    2012-01-01

    This study proposed a path model of relationships among understanding and acceptance of evolution, views on nature of science, and self-efficacy beliefs regarding teaching evolution. A total of 415 pre-service science teachers completed a series of self-report instruments for the specified purpose. After the estimation of scale scores using…

  18. On dual nature of effect of adsorbed polymeric hydroxide films on rate of different electrode processes

    International Nuclear Information System (INIS)

    Zakharkina, P.S.; Korshunov, V.N.

    1985-01-01

    The effect of cation Er 3+ hydrolysis products on the electrochemical behaviour of Zn and Na amalgams is studied. The i, t-curves are presented which are moasUred from a film Hg-electrode in 1M LiCl- and 1MNaCl solUtions both with and without the 10 -3 MErCl 3 addition, along with the I, t-dependences obtained from a rotation disk Zn-electrode at E=-1.45 B against the background of 0.1 MLi 2 SO 4 with the 1.5x10 -3 M Er 2 (SO 4 ) 3 addition. Polymeric films of REE oxohydroxo compounds exhibit a distinct dualism in the effect on the rate of different electrode reactions; provided a proton donor is the depolarizator, the films being considered confirm their name of catalytically active matrices accelerating hydrogen evolution by a modified bridge mechanism variant. In case of metal charge-ionization process these films become inhibitors and the more effective, the more hydrated is the corresponding REE ion

  19. Dealing with natural hazards in the Barcelonnette region - a multi-disciplinary collaboration from understanding to management

    Science.gov (United States)

    Kappes, Melanie; Frigerio, Simone; Luna, Byron Quan; Traveletti, Julien; Spickermann, Anke; Krzeminska, Dominika; Angignard, Marjory

    2010-05-01

    The Barcelonnette area, part of the Ubaye-Valley in the South French Alps, is highly exposed to natural hazard (mudslides, debris flows, torrential floods, river floods, avalanches and rockfalls); La Valette, Poche, Super-Sauze, Faucon are examples of well-known risk settings studied by scientists for several decades. In the framework of the Mountain Risks network, young researchers are working on different steps and aspects of the protection of the communities. It requires the collaboration of experts from different disciplines assembling the "living with risk" chain that has to cover the identification of the hazard, the risk assessment, risk management and the socio-economic and political decision-making. On the example of the Barcelonnette region, this work demonstrates such a multi-disciplinary cooperation within the Mountain Risks project. Starting with a multi-hazard analysis on a medium-scale level (1:10.000-1:50.000) for an overview over the hotspots in the basin a link is established to the local level analyses going into more detail. To forecast potential landslides in black marls and to assess the risk it is important to know the mechanisms leading to failure and the mechanisms determining subsequent movement. With respect to the Super-Sauze and La Valette mudslides detailed monitoring of hydrological features (i.e. high resolution temperature observations, large and medium scale infiltration experiments), displacement monitoring for short and long term kinematics analysis (i.e. image correlation technique applied on terrestrial oblique optical image, aerial and terrestrial laser scanning survey, differential global positioning system), small-scale testing in the laboratory (i.e. standard geotechnical, flume and centrifuge tests) and numerical modelling are performed to understand the mechanisms that might trigger and control the landslide. Integration and interpretation of these multi-source data allow to constrain conceptual models which are essential

  20. A Dual Case Study: Students' Perceptions, Self-Efficacy and Understanding of the Nature of Science in Varied Introductory Biology Laboratories

    Science.gov (United States)

    Quigley, Dena Beth Boans

    Since World War II, science education has been at the forefront of curricular reforms. Although the philosophical approach to science education has changed numerous times, the importance of the laboratory has not waned. A laboratory is meant to allow students to encounter scientific concepts in a very real, hands-on way so that they are able to either recreate experiments that have given rise to scientific theories or to use science to understand a new idea. As the interactive portion of science courses, the laboratory should not only reinforce conceptual ideas, but help students to understand the process of science and interest them in learning more about science. However, most laboratories have fallen into a safe pattern having teachers and students follow a scientific recipe, removing the understanding of and interest in science for many participants. In this study, two non-traditional laboratories are evaluated and compared with a traditional laboratory in an effort to measure student satisfaction, self-efficacy, attitudes towards science, and finally their epistemology of the nature of science (NOS). Students in all populations were administered a survey at the beginning and the end of their spring 2016 laboratory, and the survey was a mixture of qualitative questions and quantitative instruments. Overall, students who participated in one of the non-traditional labs rated their satisfaction higher and used affirming supportive statements. They also had significant increases in self-efficacy from pre to post, while the students in the traditional laboratory had a significant decrease. The students in the traditional laboratory had significant changed in attitudes towards science, as did the students in one of the non-traditional laboratories. All students lacked a firm grasp of the tenets of NOS, although one laboratory that includes explicit discussions of NOS saw improvement in at least on tenet. Data for two non-major biology laboratory populations was

  1. Selection and characterization of naturally occurring high acidification rate Streptococcus thermophilus strains.

    Science.gov (United States)

    Urshev, Zoltan; Ninova-Nikolova, Nadya; Ishlimova, Daniela; Pashova-Baltova, Kalinka; Michaylova, Michaela; Savova, Tatyana

    2014-09-03

    Among Streptococcus thermophilus cultures, the principle component of yoghurt and cheese starters, a minority of strains forms the group of 'H'-strains which show an unusually high acidification rate, grow faster and coagulate milk 3-5 hours earlier than the typical S. thermophilus cultures. A large-scale screening study was performed to select 'H'-strains of S. thermophilus from more than 100 samples of home-made yoghurt, industrial yoghurt starters and single cultures, maintained in the LBB culture collection. Only four strains - LBB.TN1, LBB.M23, LBB.M34 and LBB.M60 - were isolated/selected due to their ability to form large yellowish colonies on milk agar, supplemented with beta-glycerophosphate and bromocresol purple. While in general S. thermophilus is described as a species with limited proteolytic capacity and in contrast to all other tested S. thermophilus cultures, the four selected strains invariably gave positive amplification product with the polymerase chain reaction when primers, specific for the membrane proteinase-coding gene prt S were used. The macrorestriction profiles of the genomic DNA of the four strains confirmed that they are non-isogenic and not related to each other. When grown in milk and compared to the control industrial strain LBB.A, the four strains showed a dramatically faster acidification, coagulating milk within four hours. The application of strain TN1 or M23 as adjunct culture to industrial yoghurt starter LBB.BY5-12 resulted in shortening the fermentation time with more than 30 min.

  2. Natural radioactivity and radon exhalation rates in man-made tiles used as building materials in Japan.

    Science.gov (United States)

    Iwaoka, K; Hosoda, M; Suwankot, N; Omori, Y; Ishikawa, T; Yonehara, H; Tokonami, S

    2015-11-01

    Man-made tiles frequently used in Japan were collected, and activity concentrations and radon ((222)Rn) exhalation rates in these tiles were measured. Dose estimations for inhabitants living in houses built using these tiles were also carried out. The activity concentrations of (226)Ra, (228)Ra and (40)K in the man-made tiles were 31-170, 35-110 and 260-980 Bq kg(-1), respectively. The (222)Rn exhalation rates in the tiles were 8.8-21 μBq m(-2) s(-1). The ranges of experimental activity concentrations and (222)Rn exhalation rates were almost identical to those of natural rocks used as typical building materials in Japan. The maximum value of effective dose to inhabitants living in houses built with the man-made tiles was 0.14 mSv y(-1), which is lower than the reference level range (1-20 mSv y(-1)) for abnormally high levels of natural background radiation published in the ICRP Publication 103. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. The relationship between the rate of melatonin excretion and sleep consolidation for locomotive engineers in natural sleep settings

    Directory of Open Access Journals (Sweden)

    Ferguson Sally

    2006-08-01

    Full Text Available Abstract Background The aim of the study was to examine the role that melatonin production plays in the regulation of sleep consolidation in a population of shiftworkers working and sleeping in their natural environments. Methods 253 locomotive engineers (249 male, 4 female, mean age = 39.7 years participated in the study for a 2-week period whilst working their normal roster patterns. Participants recorded details for all sleep periods in a sleep diary and collected urine samples during each day's main sleep period. The samples were subsequently assayed for the metabolite of melatonin in urine, 6-sulphatoxymelatonin (aMT6s, and the rate of excretion during main sleep periods was calculated. Results Separate one-way factorial ANOVAs revealed a significant effect of time of sleep onset on aMT6s excretion rate, sleep duration, and subjective sleep quality. Generally, the rate of aMT6s excretion was lower, sleep duration was shorter, and sleep quality was lower for sleeps initiated during the daytime than for sleeps initiated at night. Conclusion Combined with previous studies linking melatonin production and sleep propensity, and others demonstrating the relationship between sleep consolidation and melatonin production in forced desynchrony protocols, the current results indicate that low production of melatonin may play a role in the poor consolidation of daytime sleep in natural sleep settings.

  4. Live birth rates following natural cycle IVF in women with poor ovarian response according to the Bologna criteria.

    Science.gov (United States)

    Polyzos, N P; Blockeel, C; Verpoest, W; De Vos, M; Stoop, D; Vloeberghs, V; Camus, M; Devroey, P; Tournaye, H

    2012-12-01

    What is the effect of natural cycle IVF in women with poor ovarian response according to the new ESHRE definition for poor ovarian responders: the Bologna criteria? Although natural cycle IVF is a promising treatment option for normal responders, poor ovarian responders, as described by the Bologna criteria, have a very poor prognosis and do not appear to experience substantial benefits with natural cycle IVF. Previous trials have shown that natural cycle IVF is an effective treatment for the general infertile population and might be an option for poor ovarian responders. However, none of the trials have examined the effect of natural cycle IVF in poor responders according to the Bologna criteria, the newly introduced definition by the ESHRE Working Group on Poor Ovarian Response Definition. In this trial, we examined the effect of natural cycle IVF in poor ovarian responders fulfilling the Bologna criteria. In this retrospective cohort trial, 164 consecutive patients, undergoing 469 natural cycle IVFs between 2008 and 2011 were included. Patients were stratified as poor and normal responders: 136 (390 cycles) were poor ovarian responders according to the Bologna criteria, whereas 28 women (79 treatment cycles) did not fulfil the criteria and were considered as normal responders. All patients were monitored with hormonal analysis and ultrasound scan every second day, from Day 7 or 8 of the cycle onwards. When a follicle of >16 mm was observed, ovulation was triggered with 5000 IU of i.m. hCG and oocyte retrieval was performed 32 h later. Live birth rates in poor responders according to the Bologna criteria were significantly lower compared with the control group of women; the live birth rate per cycle was 2.6 versus 8.9%, P = 0.006 and the live birth rate per treated patient was 7.4 versus 25%, P = 0.005. In poor responders according to the Bologna criteria, live birth rates were consistently low and did not differ among different age groups (≤ 35 years, 36

  5. Did natural selection make the Dutch taller? A cautionary note on the importance of quantification in understanding evolution.

    Science.gov (United States)

    Tarka, Maja; Bolstad, Geir H; Wacker, Sebastian; Räsänen, Katja; Hansen, Thomas F; Pélabon, Christophe

    2015-12-01

    One of the main achievements of the modern synthesis is a rigorous mathematical theory for evolution by natural selection. Combining this theory with statistical models makes it possible to estimate the relevant parameters so as to quantify selection and evolution in nature. Although quantification is a sign of a mature science, statistical models are unfortunately often interpreted independently of the motivating mathematical theory. Without a link to theory, numerical results do not represent proper quantifications, because they lack the connections that designate their biological meaning. Here, we want to raise awareness and exemplify this problem by examining a recent study on natural selection in a contemporary human population. Stulp et al. (2015) concluded that natural selection may partly explain the increasing stature of the Dutch population. This conclusion was based on a qualitative assessment of the presence of selection on height. Here, we provide a quantitative interpretation of these results using standard evolutionary theory to show that natural selection has had a minuscule effect. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  6. Effect of molecular weight and testing rate on adhesion property of pressure-sensitive adhesives prepared from epoxidized natural rubber

    International Nuclear Information System (INIS)

    Khan, Imran; Poh, B.T.

    2011-01-01

    Research highlights: → Elucidation of adhesion property of epoxidized natural rubber (ENR 25). → Correlation of peel and shear strength with molecular weight and rate of testing. → Confirmation of miscibility of tackifier and ENR 25 by DSC and FTIR study. → Applicability of Fox equation in ENR 25/coumarone-indene resin system. -- Abstract: The dependence of peel strength and shear strength of epoxidized natural rubber (ENR 25)-based pressure-sensitive adhesive on molecular weight and rate of testing was investigated using coumarone-indene as the tackifying resin. Toluene and polyethylene terephthalate (PET) were used as the solvent and substrate respectively throughout the study. A SHEEN hand coater was used to coat the adhesive on the substrate at a coating thickness of 120 μm. All the adhesion properties were determined by a Llyod Adhesion Tester operating at different rates of testing. Result shows that peel strength and shear strength increases up to an optimum molecular weight of 6.5 x 10 4 of ENR 25. For peel strength, the observation is attributed to the combined effects of wettability and mechanical strength of rubber at the optimum molecular weight, whereas for the shear strength, it is ascribed to the increasing amount of adhesive present in the coating layer which enhances the shear resistance of the adhesive. Peel strength and shear strength also increases with increase in rate of testing, an observation which is associated to the viscoeslastic response of the adhesive. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) study confirms the miscibility of tackifier and the ENR 25.

  7. Mandatory Climate Change Discussions in Online Classrooms: Promoting Students' Climate Literacy and Understanding of the Nature of Science

    Science.gov (United States)

    Clary, Renee M.; Wandersee, James H.

    2012-01-01

    Graduate students entered our online classrooms with robust, but nonscientific, opinions on climate change. To expose students to critical analysis of media and emphasize the nature of science, we required them to access scientific reports and participate in mandatory peer discussions. An introductory survey probed incoming knowledge and opinions,…

  8. From the Horse's Mouth: Why Scientists' Views Are Crucial to Nature of Science Understanding

    Science.gov (United States)

    Hodson, Derek; Wong, Siu Ling

    2014-01-01

    Written in response to criticism of our work by Fouad Abd-El-Khalick, this position paper reaffirms and reinforces our position about the need to broaden and enrich the scope of nature of science (NOS) oriented curricula by exposing students to the voices of practising scientists. While Abd-El-Khalick's motivation for promoting the so-called…

  9. Understanding the Nature of School Partnerships with Business in Delivery of Vocational Programmes in Schools in Australia

    Science.gov (United States)

    Polesel, John; Klatt, Malgorzata; Blake, Damian; Starr, Karen

    2017-01-01

    This article seeks to provide a school perspective on the nature and quality of the partnerships which schools form with businesses in order to deliver work placements and workplace learning in Australia. It found that the ability of schools to engage with external partners depended on the ability of school leaders to define and communicate the…

  10. Resolution of ambiguities in cartoons as an illustration of the role of pragmatics in natural language understanding by computers

    Energy Technology Data Exchange (ETDEWEB)

    Mazlack, L.J.; Paz, N.M.

    1983-01-01

    Newspaper cartoons can graphically display the result of ambiguity in human speech; the result can be unexpected and funny. Likewise, computer analysis of natural language statements also needs to successfully resolve ambiguous situations. Computer techniques already developed use restricted world knowledge in resolving ambiguous language use. This paper illustrates how these techniques can be used in resolving ambiguous situations arising in cartoons. 8 references.

  11. Toward Understanding the Nature of a Partnership between an Elementary Classroom Teacher and an Informal Science Educator

    Science.gov (United States)

    Weiland, Ingrid S.; Akerson, Valarie L.

    2013-01-01

    This study explored the nature of the relationship between a fifth-grade teacher and an informal science educator as they planned and implemented a life science unit in the classroom, and sought to define this relationship in order to gain insight into the roles of each educator. In addition, student learning as a result of instruction was…

  12. Exploring How Research Experiences for Teachers Changes Their Understandings of the Nature of Science and Scientific Inquiry

    Science.gov (United States)

    Buxner, Sanlyn R.

    2014-01-01

    The nature of science is a prevalent theme across United States national science education standards and frameworks as well as other documents that guide formal and informal science education reform. To support teachers in engaging their students in authentic scientific practices and reformed teaching strategies, research experiences for teachers…

  13. Understanding the lack of competition in natural gas markets: the impact of storage ownership and upstream competition

    Czech Academy of Sciences Publication Activity Database

    Mravec, Michal

    -, č. 342 (2007), s. 1-40 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : natural gas market * liberalization * deregulation Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp342.pdf

  14. Oil & Natural Gas Technology A new approach to understanding the occurrence and volume of natural gas hydrate in the northern Gulf of Mexico using petroleum industry well logs

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Ann [The Ohio State Univ., Columbus, OH (United States); Majumdar, Urmi [The Ohio State Univ., Columbus, OH (United States)

    2016-03-31

    The northern Gulf of Mexico has been the target for the petroleum industry for exploration of conventional energy resource for decades. We have used the rich existing petroleum industry well logs to find the occurrences of natural gas hydrate in the northern Gulf of Mexico. We have identified 798 wells with well log data within the gas hydrate stability zone. Out of those 798 wells, we have found evidence of gas hydrate in well logs in 124 wells (15% of wells). We have built a dataset of gas hydrate providing information such as location, interval of hydrate occurrence (if any) and the overall quality of probable gas hydrate. Our dataset provides a wide, new perspective on the overall distribution of gas hydrate in the northern Gulf of Mexico and will be the key to future gas hydrate research and prospecting in the area.

  15. Bike Helmets and Black Riders: Experiential Approaches to Helping Students Understand Natural Hazard Assessment and Mitigation Issues

    Science.gov (United States)

    Stein, S. A.; Kley, J.; Hindle, D.; Friedrich, A. M.

    2014-12-01

    Defending society against natural hazards is a high-stakes game of chance against nature, involving tough decisions. How should a developing nation allocate its budget between building schools for towns without ones or making existing schools earthquake-resistant? Does it make more sense to build levees to protect against floods, or to prevent development in the areas at risk? Would more lives be saved by making hospitals earthquake-resistant, or using the funds for patient care? These topics are challenging because they are far from normal experience, in that they involve rare events and large sums. To help students in natural hazard classes conceptualize them, we pose tough and thought-provoking questions about complex issues involved and explore them together via lectures, videos, field trips, and in-class and homework questions. We discuss analogous examples from the students' experiences, drawing on a new book "Playing Against Nature, Integrating Science and Economics to Mitigate Natural Hazards in an Uncertain World". Asking whether they wear bicycle helmets and why or why not shows the cultural perception of risk. Individual students' responses vary, and the overall results vary dramatically between the US, UK, and Germany. Challenges in hazard assessment in an uncertain world are illustrated by asking German students whether they buy a ticket on public transportation - accepting a known cost - or "ride black" - not paying but risking a heavy fine if caught. We explore the challenge of balancing mitigation costs and benefits via the question "If you were a student in Los Angeles, how much more would you pay in rent each month to live in an earthquake-safe building?" Students learn that interdisciplinary thinking is needed, and that due to both uncertainties and sociocultural factors, no unique or right strategies exist for a particular community, much the less all communities. However, we can seek robust policies that give sensible results given

  16. Effect of Computer Simulations at the Particulate and Macroscopic Levels on Students' Understanding of the Particulate Nature of Matter

    Science.gov (United States)

    Tang, Hui; Abraham, Michael R.

    2016-01-01

    Computer-based simulations can help students visualize chemical representations and understand chemistry concepts, but simulations at different levels of representation may vary in effectiveness on student learning. This study investigated the influence of computer activities that simulate chemical reactions at different levels of representation…

  17. Students' Understanding of the Nature of Matter and Chemical Reactions--A Longitudinal Study of Conceptual Restructuring

    Science.gov (United States)

    Øyehaug, Anne Bergliot; Holt, Anne

    2013-01-01

    This longitudinal study aims to provide greater insight into how students' understanding of matter and chemical reactions develops over time and how their knowledge structures are restructured. Four case-study students in a Norwegian primary school were followed for two years from age 10-11 to age 12-13. Researchers were responsible for…

  18. Remote sensing change detection tools for natural resource managers: Understanding concepts and tradeoffs in the design of landscape monitoring projects

    Science.gov (United States)

    Robert E. Kennedy; Philip A. Townsend; John E. Gross; Warren B. Cohen; Paul Bolstad; Wang Y. Q.; Phyllis Adams

    2009-01-01

    Remote sensing provides a broad view of landscapes and can be consistent through time, making it an important tool for monitoring and managing protected areas. An impediment to broader use of remote sensing science for monitoring has been the need for resource managers to understand the specialized capabilities of an ever-expanding array of image sources and analysis...

  19. The therapeutic effect of clinical trials: understanding placebo response rates in clinical trials – A secondary analysis

    Directory of Open Access Journals (Sweden)

    Walach Harald

    2005-08-01

    Full Text Available Abstract Background and purpose Placebo response rates in clinical trials vary considerably and are observed frequently. For new drugs it can be difficult to prove effectiveness superior to placebo. It is unclear what contributes to improvement in the placebo groups. We wanted to clarify, what elements of clinical trials determine placebo variability. Methods We analysed a representative sample of 141 published long-term trials (randomized, double-blind, placebo-controlled; duration > 12 weeks to find out what study characteristics predict placebo response rates in various diseases. Correlational and regression analyses with study characteristics and placebo response rates were carried out. Results We found a high and significant correlation between placebo and treatment response rate across diseases (r = .78; p Conclusion Medication response rates and placebo response rates in clinical trials are highly correlated. Trial characteristics can explain some portion of the variance in placebo healing rates in RCTs. Placebo response in trials is only partially due to methodological artefacts and only partially dependent on the diagnoses treated.

  20. Thai primary students' understanding of nature of science (NOS) in learning about force and motion for explicit NOS through STS approach

    Science.gov (United States)

    Jimakorn, Narakorn; Yuenyong, Chokchai

    2018-01-01

    This paper aimed to study of primary school students' understanding of nature of science in learning about force and motion for Explicit Nature of Science through science technology and society (STS) approach. Participants were 11 Grade 5 students who study in Baan Khongtaphet, Bothong, Chonburi, Thailand. This research regarded interpretive paradigm. The intervention of STS physics provided 4 weeks of teaching about force and motion through Yuenyong (2006) science technology and society (STS) approach. The issues of making skate board was brought into the class in order to enhance students learning about force and motion and applying knowledge for designing skate board. The intervention was also designed to allow students explicitly mentioning their ideas about nature of science related to learning activities of STS force and motion. Students' understanding of nature of science was interpreted through students' worksheets, participant observation, students' journal writing and informal interview. The findings revealed that majority of students could reflect their ideas related to many aspects of nature of science. This included Science demands and relies on empirical evidence; knowledge production in science shares many common factors and shared habits of mind, norms, logical thinking and methods; tentative of scientific knowledge; historical, cultural and social influences on science; historical, cultural and social influences on science; science and its methods cannot answer all questions. The study has implications for NOS teaching in Thailand primary school.

  1. Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling.

    Science.gov (United States)

    Yang, Xinyao; Zhang, Yimeng; Chen, Fangmin; Yang, Yuesuo

    2015-11-17

    The investigation on factors that affect the impact of natural organic matter (NOM) on colloid transport in complex hydraulic flow systems remains incomplete. Using our previously established approach, the interplay of flow rate and particle size on the NOM effect was quantified, using flow rates of 1 and 2 mL/min and particle sizes of 50 and 200 nm to represent small nanoparticles (1-100 nm) and large non-nano-microspheres (100-1000 nm) in the low-flow groundwater environment. Latex particles, Suwannee River humic acid (SRHA), and iron oxide-coated sand were used as model particles, NOM, and the aquifer medium, respectively. The quantitative results show NOM blocked more sites for large particles at a high flow rate: 1 μg of SRHA blocked 5.95 × 10(9) microsphere deposition sites at 2 mL/min but only 7.38 × 10(8) nanoparticle deposition sites at 1 mL/min. The particle size effect dominated over the flow rate, and the overall effect of the two is antagonistic. Granule-scale visualization of the particle packing on the NOM-presented sand surface corroborates the quantification results, revealing a more dispersed status of large particles at a high flow rate. We interpret this phenomenon as a polydispersivity effect resulting from the differential size of the particles and NOM: high flow and a high particle size enlarge the ratio of particle-blocked to NOM-blocked areas and thus the NOM blockage. To our knowledge, this is the first model-assisted quantification on the interplay of NOM, flow rate, and particle size on colloid transport. These findings are significant for nanorisk assessment and nanoremediation practices.

  2. The Jackprot Simulation Couples Mutation Rate with Natural Selection to Illustrate How Protein Evolution Is Not Random.

    Science.gov (United States)

    Paz-Y-Miño C, Guillermo; Espinosa, Avelina; Bai, Chunyan Y

    2011-09-01

    Protein evolution is not a random process. Views which attribute randomness to molecular change, deleterious nature to single-gene mutations, insufficient geological time, or population size for molecular improvements to occur, or invoke "design creationism" to account for complexity in molecular structures and biological processes, are unfounded. Scientific evidence suggests that natural selection tinkers with molecular improvements by retaining adaptive peptide sequence. We used slot-machine probabilities and ion channels to show biological directionality on molecular change. Because ion channels reside in the lipid bilayer of cell membranes, their residue location must be in balance with the membrane's hydrophobic/philic nature; a selective "pore" for ion passage is located within the hydrophobic region. We contrasted the random generation of DNA sequence for KcsA, a bacterial two-transmembrane-domain (2TM) potassium channel, from Streptomyces lividans, with an under-selection scenario, the "jackprot," which predicted much faster evolution than by chance. We wrote a computer program in JAVA APPLET version 1.0 and designed an online interface, The Jackprot Simulation http://faculty.rwu.edu/cbai/JackprotSimulation.htm, to model a numerical interaction between mutation rate and natural selection during a scenario of polypeptide evolution. Winning the "jackprot," or highest-fitness complete-peptide sequence, required cumulative smaller "wins" (rewarded by selection) at the first, second, and third positions in each of the 161 KcsA codons ("jackdons" that led to "jackacids" that led to the "jackprot"). The "jackprot" is a didactic tool to demonstrate how mutation rate coupled with natural selection suffices to explain the evolution of specialized proteins, such as the complex six-transmembrane (6TM) domain potassium, sodium, or calcium channels. Ancestral DNA sequences coding for 2TM-like proteins underwent nucleotide "edition" and gene duplications to generate the 6

  3. Teachers' Understanding of Students' Attitudes and Values toward Physical Activity in Physical Education Dropout Rates and Adolescent Obesity

    Science.gov (United States)

    Landolfi, Emilio

    2014-01-01

    Structured interviews were used to explore 10th grade teachers' understanding of students' attitudes and values toward physical education and physical activity as a variable in students' probability of dropping physical education and adolescent obesity. When asked how school-based physical education could help combat the problem of students…

  4. Understanding polysaccharide production and properties using seed coat mutants: future perspectives for the exploitation of natural variants.

    Science.gov (United States)

    North, Helen M; Berger, Adeline; Saez-Aguayo, Susana; Ralet, Marie-Christine

    2014-10-01

    The epidermal cells of the seed coat of certain species accumulate polysaccharides during seed development for cell wall reinforcement or release on imbibition to form mucilage. Seed-coat epidermal cells show natural variation in their structure and mucilage production, which could explain the diverse ecophysiological roles proposed for the latter. Arabidopsis mucilage mutants have proved to be an important tool for the identification of genes involved in the production of seed-coat polysaccharides. This review documents genes that have been characterized as playing a role in the differentiation of the epidermal cells of the arabidopsis seed coat, the natural variability in polysaccharide features of these cells and the physiological roles attributed to seed mucilage. Seed-coat epidermal cells are an excellent model for the study of polysaccharide metabolism and properties. Intra- and interspecies natural variation in the differentiation of these epidermal cells is an under-exploited resource for such studies and promises to play an important part in improving our knowledge of polysaccharide production and ecophysiological function. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Understanding Recession and Self-Rated Health with the Partial Proportional Odds Model: An Analysis of 26 Countries.

    Science.gov (United States)

    Mayer, Adam; Foster, Michelle

    2015-01-01

    Self-rated health is demonstrated to vary substantially by both personal socio-economic status and national economic conditions. However, studies investigating the combined influence of individual and country level economic indicators across several countries in the context of recent global recession are limited. This paper furthers our knowledge of the effect of recession on health at both the individual and national level. Using the Life in Transition II study, which provides data from 19,759 individuals across 26 European nations, we examine the relationship between self-rated health, personal economic experiences, and macro-economic change. Data analyses include, but are not limited to, the partial proportional odds model which permits the effect of predictors to vary across different levels of our dependent variable. Household experiences with recession, especially a loss of staple good consumption, are associated with lower self-rated health. Most individual-level experiences with recession, such as a job loss, have relatively small negative effects on perceived health; the effect of individual or household economic hardship is strongest in high income nations. Our findings also suggest that macroeconomic growth improves self-rated health in low-income nations but has no effect in high-income nations. Individuals with the greatest probability of "good" self-rated health reside in wealthy countries ($23,910 to $50, 870 GNI per capita). Both individual and national economic variables are predictive of self-rated health. Personal and household experiences are most consequential for self-rated health in high income nations, while macroeconomic growth is most consequential in low-income nations.

  6. Discussion about the range of natural radiation exposure rate found in dwelling-houses in the Federal Republic of Germany and in Poland

    International Nuclear Information System (INIS)

    Schmier, H.; Pensko, J.; Wicke, A.

    1982-01-01

    In this paper the range of natural radiation exposure rate found in dwelling-houses is discussed. The source of this exposure are natural radionuclides 40 K, 226 Ra, 232 Th and their decay products widely distributed in soil and in building materials. The resulting whole body dose equivalent rate of gamma radiation is compared to the effective dose equivalent rate of alpha radiation originating from 222 Rn diffusing out of building materials and decaying to alpha emitting short living daughters. (Author) [de

  7. Seasonal Changes in Mycosporine-Like Amino Acid Production Rate with Respect to Natural Phytoplankton Species Composition

    Directory of Open Access Journals (Sweden)

    Sun-Yong Ha

    2015-11-01

    Full Text Available After in situ incubation at the site for a year, phytoplanktons in surface water were exposed to natural light in temperate lakes (every month; thereafter, the net production rate of photoprotective compounds (mycosporine-like amino acids, MAAs was calculated using 13C labeled tracer. This is the first report describing seasonal variation in the net production rate of individual MAAs in temperate lakes using a compound-specific stable isotope method. In the mid-latitude region of the Korean Peninsula, UV radiation (UVR usually peaks from July to August. In Lake Paldang and Lake Cheongpyeong, diatoms dominated among the phytoplankton throughout the year. The relative abundance of Cyanophyceae (Anabaena spiroides reached over 80% during July in Lake Cheongpyeong. Changes in phytoplankton abundance indicate that the phytoplankton community structure is influenced by seasonal changes in the net production rate and concentration of MAAs. Notably, particulate organic matter (POM showed a remarkable change based on the UV intensity occurring during that period; this was because of the fact that cyanobacteria that are highly sensitive to UV irradiance dominated the community. POM cultured in Lake Paldang had the greatest shinorine (SH production rate during October, i.e., 83.83 ± 10.47 fgC·L−1·h−1. The dominance of diatoms indicated that they had a long-term response to UVR. Evaluation of POM cultured in Lake Cheongpyeong revealed that there was an increase in the net MAA production in July (when UVR reached the maximum; a substantial amount of SH, i.e., 17.62 ± 18.34 fgC·L−1·h−1, was recorded during this period. Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure. In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae.

  8. Seasonal Changes in Mycosporine-Like Amino Acid Production Rate with Respect to Natural Phytoplankton Species Composition.

    Science.gov (United States)

    Ha, Sun-Yong; Lee, Yeonjung; Kim, Min-Seob; Kumar, K Suresh; Shin, Kyung-Hoon

    2015-11-06

    After in situ incubation at the site for a year, phytoplanktons in surface water were exposed to natural light in temperate lakes (every month); thereafter, the net production rate of photoprotective compounds (mycosporine-like amino acids, MAAs) was calculated using (13)C labeled tracer. This is the first report describing seasonal variation in the net production rate of individual MAAs in temperate lakes using a compound-specific stable isotope method. In the mid-latitude region of the Korean Peninsula, UV radiation (UVR) usually peaks from July to August. In Lake Paldang and Lake Cheongpyeong, diatoms dominated among the phytoplankton throughout the year. The relative abundance of Cyanophyceae (Anabaena spiroides) reached over 80% during July in Lake Cheongpyeong. Changes in phytoplankton abundance indicate that the phytoplankton community structure is influenced by seasonal changes in the net production rate and concentration of MAAs. Notably, particulate organic matter (POM) showed a remarkable change based on the UV intensity occurring during that period; this was because of the fact that cyanobacteria that are highly sensitive to UV irradiance dominated the community. POM cultured in Lake Paldang had the greatest shinorine (SH) production rate during October, i.e., 83.83 ± 10.47 fgC·L(-1)·h(-1). The dominance of diatoms indicated that they had a long-term response to UVR. Evaluation of POM cultured in Lake Cheongpyeong revealed that there was an increase in the net MAA production in July (when UVR reached the maximum); a substantial amount of SH, i.e., 17.62 ± 18.34 fgC·L(-1)·h(-1), was recorded during this period. Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure. In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae).

  9. Global Scale Attribution of Anthropogenic and Natural Dust Sources and their Emission Rates Based on MODIS Deep Blue Aerosol Products

    Science.gov (United States)

    Ginoux, Paul; Prospero, Joseph M.; Gill, Thomas E.; Hsu, N. Christina; Zhao, Ming

    2012-01-01

    Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Here we present a global-scale high-resolution (0.1 deg) mapping of sources based on Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue estimates of dust optical depth in conjunction with other data sets including land use. We ascribe dust sources to natural and anthropogenic (primarily agricultural) origins, calculate their respective contributions to emissions, and extensively compare these products against literature. Natural dust sources globally account for 75% of emissions; anthropogenic sources account for 25%. North Africa accounts for 55% of global dust emissions with only 8% being anthropogenic, mostly from the Sahel. Elsewhere, anthropogenic dust emissions can be much higher (75% in Australia). Hydrologic dust sources (e.g., ephemeral water bodies) account for 31% worldwide; 15% of them are natural while 85% are anthropogenic. Globally, 20% of emissions are from vegetated surfaces, primarily desert shrublands and agricultural lands. Since anthropogenic dust sources are associated with land use and ephemeral water bodies, both in turn linked to the hydrological cycle, their emissions are affected by climate variability. Such changes in dust emissions can impact climate, air quality, and human health. Improved dust emission estimates will require a better mapping of threshold wind velocities, vegetation dynamics, and surface conditions (soil moisture and land use) especially in the sensitive regions identified here, as well as improved ability to address small-scale convective processes producing dust via cold pool (haboob) events frequent in monsoon regimes.

  10. Implementation of 5E Inquiry Incorporated with Analogy Learning Approach to Enhance Conceptual Understanding of Chemical Reaction Rate for Grade 11 Students

    Science.gov (United States)

    Supasorn, Saksri; Promarak, Vinich

    2015-01-01

    The main purpose of this study was to enhance student understanding of the scientific concepts of chemical reaction rate. Forty-four grade 11 students were the target group. The treatment tools were seven learning plans of 5E inquiry incorporated with an analogy learning approach during 15 hours of class time. In each learning plan, the students…

  11. Understanding the Effect of Response Rate and Class Size Interaction on Students Evaluation of Teaching in a Higher Education

    Science.gov (United States)

    Al Kuwaiti, Ahmed; AlQuraan, Mahmoud; Subbarayalu, Arun Vijay

    2016-01-01

    Objective: This study aims to investigate the interaction between response rate and class size and its effects on students' evaluation of instructors and the courses offered at a higher education Institution in Saudi Arabia. Study Design: A retrospective study design was chosen. Methods: One thousand four hundred and forty four different courses…

  12. Understanding semantics

    DEFF Research Database (Denmark)

    Thrane, Torben

    1997-01-01

    Understanding natural language is a cognitive, information-driven process. Discussing some of the consequences of this fact, the paper offers a novel look at the semantic effect of lexical nouns and the identification of reference types....

  13. Fuzzy time series forecasting model with natural partitioning length approach for predicting the unemployment rate under different degree of confidence

    Science.gov (United States)

    Ramli, Nazirah; Mutalib, Siti Musleha Ab; Mohamad, Daud

    2017-08-01

    Fuzzy time series forecasting model has been proposed since 1993 to cater for data in linguistic values. Many improvement and modification have been made to the model such as enhancement on the length of interval and types of fuzzy logical relation. However, most of the improvement models represent the linguistic term in the form of discrete fuzzy sets. In this paper, fuzzy time series model with data in the form of trapezoidal fuzzy numbers and natural partitioning length approach is introduced for predicting the unemployment rate. Two types of fuzzy relations are used in this study which are first order and second order fuzzy relation. This proposed model can produce the forecasted values under different degree of confidence.

  14. The public understanding of nanotechnology in the food domain: the hidden role of views on science, technology, and nature.

    Science.gov (United States)

    Vandermoere, Frederic; Blanchemanche, Sandrine; Bieberstein, Andrea; Marette, Stephan; Roosen, Jutta

    2011-03-01

    In spite of great expectations about the potential of nanotechnology, this study shows that people are rather ambiguous and pessimistic about nanotechnology applications in the food domain. Our findings are drawn from a survey of public perceptions about nanotechnology food and nanotechnology food packaging (N = 752). Multinomial logistic regression analyses further reveal that knowledge about food risks and nanotechnology significantly influences people's views about nanotechnology food packaging. However, knowledge variables were unrelated to support for nanofood, suggesting that an increase in people's knowledge might not be sufficient to bridge the gap between the excitement some business leaders in the food sector have and the restraint of the public. Additionally, opposition to nanofood was not related to the use of heuristics but to trust in governmental agencies. Furthermore, the results indicate that public perceptions of nanoscience in the food domain significantly relate to views on science, technology, and nature.

  15. A Global-Scale Estimate of Ecosystem Services from Urban Agriculture: Understanding Incentives for Natural Capital in Cities

    Science.gov (United States)

    Clinton, N.; Stuhlmacher, M.; Miles, A.; Uludere, N.; Wagner, M.; Georgescu, M.; Herwig, C.; Gong, P.

    2017-12-01

    Despite substantial interest in urban agriculture, little is known about the aggregate benefits conferred by natural capital for growing food in cities. Here we perform a scenario-based analysis to quantify ecosystem services from adoption of urban agriculture at varying intensity. To drive the scenarios, we created global-scale estimates of vacant land, rooftop and building surface area, at one kilometer resolution, from remotely sensed and modeled geospatial data. We used national scale agricultural reports, climate and other geospatial data at global scale to estimate agricultural production and economic returns, storm-water avoidance, energy savings from avoided heating and cooling costs, and ecosystem services provided by nitrogen sequestration, pollination and biocontrol of pests. The results indicate that vacant lands, followed by rooftops, represent the largest opportunities for natural capital put to agricultural use in urban areas. Ecosystem services from putting such spaces to productive use are dominated by agricultural returns, but energy savings conferred by insulative characteristics of growth substrate also provide economic incentives. Storm water avoidance was estimated to be substantial, but no economic value was estimated. Relatively low economic returns were estimated from the other ecosystem services examined. In aggregate, approximately $10-100 billion in economic incentives, before costs, were estimated. The results showed that relatively developed, high-income countries stand the most to gain from urban agricultural adoption due to the unique combination of climate, crop mixture and crop prices. While the results indicate that urban agriculture is not a panacea for urban food security issues, there is potential to simultaneously ameliorate multiple issues around food, energy and water in urbanized areas.

  16. Understanding the nature of information seeking behavior in critical care: implications for the design of health information technology.

    Science.gov (United States)

    Kannampallil, Thomas G; Franklin, Amy; Mishra, Rashmi; Almoosa, Khalid F; Cohen, Trevor; Patel, Vimla L

    2013-01-01

    Information in critical care environments is distributed across multiple sources, such as paper charts, electronic records, and support personnel. For decision-making tasks, physicians have to seek, gather, filter and organize information from various sources in a timely manner. The objective of this research is to characterize the nature of physicians' information seeking process, and the content and structure of clinical information retrieved during this process. Eight medical intensive care unit physicians provided a verbal think-aloud as they performed a clinical diagnosis task. Verbal descriptions of physicians' activities, sources of information they used, time spent on each information source, and interactions with other clinicians were captured for analysis. The data were analyzed using qualitative and quantitative approaches. We found that the information seeking process was exploratory and iterative and driven by the contextual organization of information. While there was no significant differences between the overall time spent paper or electronic records, there was marginally greater relative information gain (i.e., more unique information retrieved per unit time) from electronic records (t(6)=1.89, p=0.1). Additionally, information retrieved from electronic records was at a higher level (i.e., observations and findings) in the knowledge structure than paper records, reflecting differences in the nature of knowledge utilization across resources. A process of local optimization drove the information seeking process: physicians utilized information that maximized their information gain even though it required significantly more cognitive effort. Implications for the design of health information technology solutions that seamlessly integrate information seeking activities within the workflow, such as enriching the clinical information space and supporting efficient clinical reasoning and decision-making, are discussed. Copyright © 2012 Elsevier B.V. All

  17. The logic of comparative life history studies for estimating key parameters, with a focus on natural mortality rate

    Science.gov (United States)

    Hoenig, John M; Then, Amy Y.-H.; Babcock, Elizabeth A.; Hall, Norman G.; Hewitt, David A.; Hesp, Sybrand A.

    2016-01-01

    There are a number of key parameters in population dynamics that are difficult to estimate, such as natural mortality rate, intrinsic rate of population growth, and stock-recruitment relationships. Often, these parameters of a stock are, or can be, estimated indirectly on the basis of comparative life history studies. That is, the relationship between a difficult to estimate parameter and life history correlates is examined over a wide variety of species in order to develop predictive equations. The form of these equations may be derived from life history theory or simply be suggested by exploratory data analysis. Similarly, population characteristics such as potential yield can be estimated by making use of a relationship between the population parameter and bio-chemico–physical characteristics of the ecosystem. Surprisingly, little work has been done to evaluate how well these indirect estimators work and, in fact, there is little guidance on how to conduct comparative life history studies and how to evaluate them. We consider five issues arising in such studies: (i) the parameters of interest may be ill-defined idealizations of the real world, (ii) true values of the parameters are not known for any species, (iii) selecting data based on the quality of the estimates can introduce a host of problems, (iv) the estimates that are available for comparison constitute a non-random sample of species from an ill-defined population of species of interest, and (v) the hierarchical nature of the data (e.g. stocks within species within genera within families, etc., with multiple observations at each level) warrants consideration. We discuss how these issues can be handled and how they shape the kinds of questions that can be asked of a database of life history studies.

  18. Assessing understanding of the nature of science and science self-efficacy in undergraduates involved in research in an introductory geology course

    Science.gov (United States)

    Moss, Elizabeth Louise

    As part of a campus-wide effort to transform introductory science courses to be more engaging and to more accurately convey the excitement of discovery in science, we have re-created the curriculum of our introductory geology lab. We have transformed what was a series of `cookbook' lab activities into a series of activities based in scientific inquiry and cooperative learning and have included a six-week, student driven research project focused on local groundwater and surface water issues, seeking to determine whether or not this new curriculum was an effective means to increase students' understanding of the nature of science and self-efficacy towards science. In addition to developing the research project curriculum, we worked with other university faculty to create a local hydrology research station which included eight monitoring wells and a stream gage, allowing students to collect their own water-level and water-quality data as well as to retrieve automatically collected data. In order to measure nature of science understanding, we used a modified version of the Student Understanding of Science and Scientific Inquiry questionnaire (Liang et al., 2005; Clough, 2010). We modified a vocational self-efficacy survey (Riggs et al. 1994) to measure science self-efficacy. Both instruments had average Cronbach's alpha values >0.8, making them reliable for our study. After three semesters of collecting data, we have found that an authentic research project slightly improves, but does not significantly increase overall nature of science understanding or science self-efficacy. Dis-aggregating the data into demographic sub-groups, nature of science understanding increased relatively more in non-STEM students than STEM students, and science self-efficacy increased relatively more in STEM students than non-STEM students. We also measured changes in students' understanding of geologic concepts in the Fall 2011 and Spring 2012 semesters. We gave students enrolled in the lab

  19. Red states, blue states, and divorce: understanding the impact of conservative Protestantism on regional variation in divorce rates.

    Science.gov (United States)

    Glass, Jennifer; Levchak, Philip

    2014-01-01

    Why do states with larger proportions of religious conservatives have higher divorce rates than states with lower proportions of religious conservatives? This project examines whether earlier transitions to marriage and parenthood among conservative Protestants (known risk factors for divorce) contribute to this paradox while attending to other plausible explanations. County-level demographic information from all 50 states is combined from a variety of public data sources and merged with individual records from the National Surveys of Family Growth to estimate both aggregated county and multilevel individual models of divorce. Results show that individual religious conservatism is positively related to individual divorce risk, solely through the earlier transitions to adulthood and lower incomes of conservative Protestants. However, the proportion of conservative Protestants in a county is also independently and positively associated with both the divorce rate in that county and an individual's likelihood of divorcing. The earlier family formation and lower levels of educational attainment and income in counties with a higher proportion of conservative Protestants can explain a substantial portion of this association. Little support is found for alternative explanations of the association between religious conservatism and divorce rates, including the relative popularity of marriage versus cohabitation across counties.

  20. Learning the 'grammar of science': The influence of a physical science content course on teachers' understanding of the nature of science

    Science.gov (United States)

    Hanuscin, Deborah L.

    This research examined the development of practicing K--8 teachers' views of the nature of science (NOS) within a physical science content course. Reforms in science education have called for the teaching of science as inquiry. In order to achieve the vision of the reforms, teachers must understand science, both a body of knowledge and as a process, but also the very nature of science itself-or the values and assumptions inherent in the construction of scientific knowledge. NOS has been deemed a critical component of scientific literacy, with implications for making informed decisions about scientific claims. Research has indicated that despite the emphasis of reforms, teachers generally do not possess accurate views of NOS. Recent work in science education has led to the recommendation that efforts undertaken within teacher education programs to improve teachers' understanding of NOS can be enhanced through relevant coursework in other academic areas, including the sciences. The purpose of this dissertation was to provide an empirical basis for this recommendation, by examining the development of teachers' views of NOS within a physical science content course. To this end, the researcher employed qualitative methodology including participant observation, interview, document analysis, and questionnaire to assess teacher participants' views of the nature of science and the impact of their experience in the content course on these views. As a result of this research, implications for both the course design and science teacher education have been described. In addition, various aspects of the community of practice that characterizes the classroom that inhibit the development of understandings about the nature of science are identified. It is argued that instruction in NOS should be approached from the perspective that builds bridges between the communities of practice of learners and of scientists.

  1. Informative Nature and Nonlinearity of Lagged Poincaré Plots Indices in Analysis of Heart Rate Variability

    Directory of Open Access Journals (Sweden)

    Berik Koichubekov

    2017-10-01

    Full Text Available Lagged Poincaré plots have been successful in characterizing abnormal cardiac function. However, the current research practices do not favour any specific lag of Poincaré plots, thus complicating the comparison of results of different researchers in their analysis of heart rate of healthy subjects and patients. We researched the informative nature of lagged Poincaré plots in different states of the autonomic nervous system. It was tested in three models: different age groups, groups with different balance of autonomous regulation, and in hypertensive patients. Correlation analysis shows that for lag l = 6, SD1/SD2 has weak (r = 0.33 correlation with linear parameters of heart rate variability (HRV. For l more than 6 it displays even less correlation with linear parameters, but the changes in SD1/SD2 become statistically insignificant. Secondly, surrogate data tests show that the real SD1/SD2 is statistically different from its surrogate value and the conclusion could be made that the heart rhythm has nonlinear properties. Thirdly, the three models showed that for different functional states of the autonomic nervous system (ANS, SD1/SD2 ratio varied only for lags l = 5 and 6. All of this allow to us to give cautious recommendation to use SD1/SD2 with lags 5 and 6 as a nonlinear characteristic of HRV. The received data could be used as the basis for continuing the research in standardisation of nonlinear analytic methods.

  2. Measurement of natural radioactivity in Jordanian building materials and their contribution to the public indoor gamma dose rate

    International Nuclear Information System (INIS)

    Sharaf, J.M.; Hamideen, M.S.

    2013-01-01

    This study is undertaken to determine the activity concentration of 226 Ra, 232 Th and 40 K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of 226 Ra, 232 Th, and 40 K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan. - highlights: • The doses and risk factors associated with exposure to natural gamma radiation. • External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated. • Only granite and ceramic samples, usually used as secondary building materials, were found to exceed recommended limits

  3. Natural variation in learning rate and memory dynamics in parasitoid wasps: opportunities for converging ecology and neuroscience

    Science.gov (United States)

    Hoedjes, Katja M.; Kruidhof, H. Marjolein; Huigens, Martinus E.; Dicke, Marcel; Vet, Louise E. M.; Smid, Hans M.

    2011-01-01

    Although the neural and genetic pathways underlying learning and memory formation seem strikingly similar among species of distant animal phyla, several more subtle inter- and intraspecific differences become evident from studies on model organisms. The true significance of such variation can only be understood when integrating this with information on the ecological relevance. Here, we argue that parasitoid wasps provide an excellent opportunity for multi-disciplinary studies that integrate ultimate and proximate approaches. These insects display interspecific variation in learning rate and memory dynamics that reflects natural variation in a daunting foraging task that largely determines their fitness: finding the inconspicuous hosts to which they will assign their offspring to develop. We review bioassays used for oviposition learning, the ecological factors that are considered to underlie the observed differences in learning rate and memory dynamics, and the opportunities for convergence of ecology and neuroscience that are offered by using parasitoid wasps as model species. We advocate that variation in learning and memory traits has evolved to suit an insect's lifestyle within its ecological niche. PMID:21106587

  4. Understanding the formative stage of technological innovation system development: The case of natural gas as an automotive fuel

    International Nuclear Information System (INIS)

    Suurs, Roald A.A.; Hekkert, Marko P.; Kieboom, Sander; Smits, Ruud E.H.M.

    2010-01-01

    This study contributes to insights into mechanisms that influence the successes and failures of emerging energy technologies. It is assumed that for an emerging technology to fruitfully develop, it should be fostered by a Technological Innovation System (TIS), which is the network of actors, institutions and technologies in which it is embedded. For an emerging technology a TIS has yet to be built up. This research focuses on the dynamics of this build-up process by mapping the development of seven key activities: so-called system functions. The main contribution revolves around the notion of cumulative causation, or the phenomenon that the build-up of a TIS accelerates due to system functions reinforcing each other over time. As an empirical basis, an analysis is provided of the historical development of the TIS around automotive natural gas technology in the Netherlands (1970-2007). The results show that this TIS undergoes a gradual build-up in the 1970s, followed by a breakdown in the 1980s and, again, a build-up from 2000 to 2007. It is shown that underlying these trends are different forms of cumulative causation, here called motors of innovation. The study provides strategic insights for practitioners that aspire to support such motors of innovation.

  5. Epidemiological studies on disturbances of human fetal development in areas with various doses of natural background radiation. I. Relationship between incidences of Down's syndrome or visible malformation and gonad dose equivalent rate of natural background radiation

    International Nuclear Information System (INIS)

    Ujeno, Y.

    1985-01-01

    The relationship between environmental radiation to the gonads and incidences of Down's syndrome and visible malformation was analyzed using Kendall's rank correlation method. The subjects, studied during a 3-yr period (1979-1981), were inhabitants of 46 prefectures in Japan that had various dose rates of natural background ionizing radiation. Results showed that the natural background very low-dose radiation rate was not a predominant factor responsible for inducing Down's syndrome or other visible malformations

  6. Do monkey F5 mirror neurons show changes in firing rate during repeated observation of natural actions?

    Science.gov (United States)

    Kraskov, A.; Lemon, R. N.

    2013-01-01

    Mirror neurons were first discovered in area F5 of macaque monkeys. In humans, noninvasive studies have demonstrated an increased blood oxygen level-dependent (BOLD) signal in homologous motor areas during action observation. One approach to demonstrating that this indicates the existence of mirror neurons in humans has been to employ functional (f)MRI adaptation to test whether the same population of neurons is active during both observation and execution conditions. Although a number of human studies have reported fMRI adaptation in these areas, a recent study has shown that macaque mirror neurons do not attenuate their firing rate with two repetitions. Here we investigated whether mirror neurons modulate their firing rate when monkeys observed the same repeated natural action multiple times. We recorded from 67 mirror neurons in area F5 of two macaque monkeys while they observed an experimenter perform a reach-to-grasp action on a small food reward using a precision grip. Although no changes were detectable for the first two repetitions, we show that both the firing rate and the latency at which mirror neurons discharged during observation were subtly modulated by the repetition of the observed action over 7–10 trials. Significant adaption was mostly found in the period immediately before the grasp was performed. We also found that the local field potential activity in F5 (beta-frequency range, 16–23 Hz), which is attenuated during action observation, also showed systematic changes with repeated observation. These LFP changes occurred well in advance of the mirror neuron adaptation. We conclude that macaque mirror neurons can show intra-modal adaptation, but whether this is related to fMRI adaptation of the BOLD signal requires further investigation. PMID:24371289

  7. Do monkey F5 mirror neurons show changes in firing rate during repeated observation of natural actions?

    Science.gov (United States)

    Kilner, J M; Kraskov, A; Lemon, R N

    2014-03-01

    Mirror neurons were first discovered in area F5 of macaque monkeys. In humans, noninvasive studies have demonstrated an increased blood oxygen level-dependent (BOLD) signal in homologous motor areas during action observation. One approach to demonstrating that this indicates the existence of mirror neurons in humans has been to employ functional (f)MRI adaptation to test whether the same population of neurons is active during both observation and execution conditions. Although a number of human studies have reported fMRI adaptation in these areas, a recent study has shown that macaque mirror neurons do not attenuate their firing rate with two repetitions. Here we investigated whether mirror neurons modulate their firing rate when monkeys observed the same repeated natural action multiple times. We recorded from 67 mirror neurons in area F5 of two macaque monkeys while they observed an experimenter perform a reach-to-grasp action on a small food reward using a precision grip. Although no changes were detectable for the first two repetitions, we show that both the firing rate and the latency at which mirror neurons discharged during observation were subtly modulated by the repetition of the observed action over 7-10 trials. Significant adaption was mostly found in the period immediately before the grasp was performed. We also found that the local field potential activity in F5 (beta-frequency range, 16-23 Hz), which is attenuated during action observation, also showed systematic changes with repeated observation. These LFP changes occurred well in advance of the mirror neuron adaptation. We conclude that macaque mirror neurons can show intra-modal adaptation, but whether this is related to fMRI adaptation of the BOLD signal requires further investigation.

  8. Characterization of the rate and temperature sensitivities of bacterial remineralization of dissolved organic phosphorus by natural populations

    Directory of Open Access Journals (Sweden)

    Angelicque E. White

    2012-08-01

    Full Text Available Production, transformation, and degradation are the principal components of the cycling of dissolved organic matter (DOM in marine systems. Heterotrophic Bacteria (and Archaea play a large part in this cycling via enzymatic decomposition and intracellular transformations of organic material to inorganic carbon (C, nitrogen (N , and phosphorus (P. The rate and magnitude of inorganic nutrient regeneration from DOM is related to the elemental composition and lability of DOM substrates as well as the nutritional needs of the mediating organisms. While many previous efforts have focused on C and N cycling of DOM, less is known in regards to the controls of organic P utilization and remineralization by natural populations of bacteria. In order to constrain the relative time scales and degradation of select dissolved organic P (DOP compounds we have conducted a series of experiments focused on (1 assessment of the short-term lability of a range of DOP compounds, (2 characterization of labile DOP remineralization rates and (3 examination of temperature sensitivities of labile DOP remineralization for varying bacterial populations. Results reinforce previous findings of monoester and polyphosphate lability and the relative recalcitrance of a model phosphonate: 2-aminoethylphosphonate. High resolution time-series of P monoester remineralization indicates decay constants on the order of 0.67-7.04 d-1 for bacterial populations isolated from coastal and open ocean surface waters. The variability of these rates is predictably related to incubation temperature and initial concentrations of heterotrophic bacteria. Additional controls on DOP hydrolysis included seasonal shifts in bacterial populations and the physiological state of bacteria at the initiation of DOP addition experiments. Composite results indicate that bacterial hydrolysis of P-monoesters exceeds bacterial P demand and thus DOP remineralization efficiency may control P availability to autotrophs.

  9. Enhancement of natural ventilation rate and attic heat gain reduction of roof solar collector using radiant barrier

    Energy Technology Data Exchange (ETDEWEB)

    Puangsombut, W.; Hirunlabh, J. [Building Scientific Research Center, King Mongkut' s University of Technology Thonburi, Bangmod, Thungkru, Bangkok 10140 (Thailand); Khedari, J.; Win, M.M. [South-East Asia University, 19/1 Petkasem Rd., Nongkhaem, Bangkok 10160 (Thailand); Zeghmati, B. [Centre d' Etudes Fondamentales-Groupe de Mechanique Acoustique et Instrumentation, Universite de Perpignan, 66870, Perpignan (France)

    2007-06-15

    Presented in this paper are the experimental results on natural ventilation flow rate enhancement and attic heat gain reduction of a roof solar collector equipped with a radiant barrier (RB). Investigation was conducted using an open ended inclined rectangular channel with an RB. The RB was used on the lower plate while the upper plate was heated with constant heat flux intensity. The channel dimensions are 1.5 x 0.70 x 0.19 m. The slope of the channel was fixed at 30 from horizontal plane. Four heat flux (190.5, 285.7, 380.9 and 476.2 W m{sup -2}) and five air gap space (3, 5, 7, 9 and 11 cm) were considered. Data analysis was made to determine the free convection heat transfer coefficient and induced airflow rate using two dimensionless parameters, viz., Nusselt number (Nu) and Reynolds number (Re). The Nu and Re were correlated as a function of Ra sin30 and channel aspect ratio defined as the ratio of air gap space to the channel length. The relations obtained were as follows: Nu=0.371(Ra sin 30){sup 0.2223}(S/L){sup -0.0469} and Re=191.68(Ra sin30){sup 0.1213}(S/L){sup -0.085}. When compared to a conventional roof solar configuration with gypsum board on the lower part, it was observed that the use of RB increased convective heat transfer and airflow rate by about 40-50%, thereby increasing heat transfer reduction through the lower plate by about 50%. The developed correlations are useful for the design of such open-ended channels like the roof solar collector for passive ventilation of houses. (author)

  10. The effects of conducting authentic field-geology research on high school students' understanding of the nature of science, and their views of themselves as research scientists

    Science.gov (United States)

    Millette, Patricia M.

    Authentic field geology research is a inquiry method that encourages students to interact more with their local environment, and by solving genuine puzzles, begin to increase their intuitive understanding of the nature and processes of science. The goal of the current study was to determine if conducting authentic field research and giving high school students the opportunity to present findings to adult audiences outside of the school setting 1) enhances students' understanding of the nature of science, and 2) affects students views of themselves as researchers. To accomplish this, ninth-grade students from a public school in northern New England engaged in a community-initiated glacial geology problem, completed a field research investigation, and presented their findings at several professional conferences. Following the completion of this student-centered field research, I investigated its effects by using a mixed methods approach consisting of qualitative and quantitative data from two sources. These included selected questions from an open-response survey (VNOS-c), and interviews that were conducted with fifteen of the students of different ages and genders. Findings show that conducting original field research seems to have a positive influence on these students' understanding of the NOS as well as the processes of science. Many of the students reported feelings of accomplishment, acceptance of responsibility for the investigation, a sense of their authentic contribution to the body of scientific knowledge in the world, and becoming scientists. This type of authentic field investigation is significant because recent reforms in earth-science education stress the importance of students learning about the nature and processes of scientific knowledge along with science content.

  11. High-resolution genetic map for understanding the effect of genome-wide recombination rate on nucleotide diversity in watermelon.

    Science.gov (United States)

    Reddy, Umesh K; Nimmakayala, Padma; Levi, Amnon; Abburi, Venkata Lakshmi; Saminathan, Thangasamy; Tomason, Yan R; Vajja, Gopinath; Reddy, Rishi; Abburi, Lavanya; Wehner, Todd C; Ronin, Yefim; Karol, Abraham

    2014-09-15

    We used genotyping by sequencing to identify a set of 10,480 single nucleotide polymorphism (SNP) markers for constructing a high-resolution genetic map of 1096 cM for watermelon. We assessed the genome-wide variation in recombination rate (GWRR) across the map and found an association between GWRR and genome-wide nucleotide diversity. Collinearity between the map and the genome-wide reference sequence for watermelon was studied to identify inconsistency and chromosome rearrangements. We assessed genome-wide nucleotide diversity, linkage disequilibrium (LD), and selective sweep for wild, semi-wild, and domesticated accessions of Citrullus lanatus var. lanatus to track signals of domestication. Principal component analysis combined with chromosome-wide phylogenetic study based on 1563 SNPs obtained after LD pruning with minor allele frequency of 0.05 resolved the differences between semi-wild and wild accessions as well as relationships among worldwide sweet watermelon. Population structure analysis revealed predominant ancestries for wild, semi-wild, and domesticated watermelons as well as admixture of various ancestries that were important for domestication. Sliding window analysis of Tajima's D across various chromosomes was used to resolve selective sweep. LD decay was estimated for various chromosomes. We identified a strong selective sweep on chromosome 3 consisting of important genes that might have had a role in sweet watermelon domestication. Copyright © 2014 Reddy et al.

  12. Are radiosensitivity data derived from natural field conditions consistent with data from controlled exposures? A case study of Chernobyl wildlife chronically exposed to low dose rates.

    Science.gov (United States)

    Garnier-Laplace, J; Geras'kin, S; Della-Vedova, C; Beaugelin-Seiller, K; Hinton, T G; Real, A; Oudalova, A

    2013-07-01

    The discrepancy between laboratory or controlled conditions ecotoxicity tests and field data on wildlife chronically exposed to ionising radiation is presented for the first time. We reviewed the available chronic radiotoxicity data acquired in contaminated fields and used a statistical methodology to support the comparison with knowledge on inter-species variation of sensitivity to controlled external γ irradiation. We focus on the Chernobyl Exclusion Zone and effects data on terrestrial wildlife reported in the literature corresponding to chronic dose rate exposure situations (from background ~100 nGy/h up to ~10 mGy/h). When needed, we reconstructed the dose rate to organisms and obtained consistent unbiased data sets necessary to establish the dose rate-effect relationship for a number of different species and endpoints. Then, we compared the range of variation of radiosensitivity of species from the Chernobyl-Exclusion Zone with the statistical distribution established for terrestrial species chronically exposed to purely gamma external irradiation (or chronic Species radioSensitivity Distribution - SSD). We found that the best estimate of the median value (HDR50) of the distribution established for field conditions at Chernobyl (about 100 μGy/h) was eight times lower than the one from controlled experiments (about 850 μGy/h), suggesting that organisms in their natural environmental were more sensitive to radiation. This first comparison highlights the lack of mechanistic understanding and the potential confusion coming from sampling strategies in the field. To confirm the apparent higher sensitive of wildlife in the Chernobyl Exclusion Zone, we call for more a robust strategy in field, with adequate design to deal with confounding factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. The discovery of X-rays diffraction: From crystals to DNA. A case study to promote understanding of the nature of science and of its interdisciplinary character

    Science.gov (United States)

    Guerra, Francesco; Leone, Matteo; Robotti, Nadia

    2016-05-01

    The advantages of introducing history of science topics into the teaching of science has been advocated by a large number of scholars within the science education community. One of the main reasons given for using history of science in teaching is its power to promote understanding of the nature of science (NOS). In this respect, the historical case of X-rays diffraction, from the discovery of Max von Laue (1912) to the first X-rays diffraction photographs of DNA (1953), is a case in point for showing that a correct experimental strategy and a favourable theoretical context are not enough to make a scientific discovery.

  14. The discovery of X-rays diffraction: From crystals to DNA. A case study to promote understanding of the nature of science and of its interdisciplinary character

    International Nuclear Information System (INIS)

    Guerra, Francesco; Leone, Matteo; Robotti, Nadia

    2015-01-01

    The advantages of introducing history of science topics into the teaching of science has been advocated by a large number of scholars within the science education community. One of the main reasons given for using history of science in teaching is its power to promote understanding of the nature of science (NOS). In this respect, the historical case of X-rays diffraction, from the discovery of Max von Laue (1912) to the first X-rays diffraction photographs of DNA (1953), is a case in point for showing that a correct experimental strategy and a favourable theoretical context are not enough to make a scientific discovery.

  15. A natural saline soil as a model for understanding to what extent the concentration of salt affects the distribution of microorganisms

    Science.gov (United States)

    Canfora, Loredana; Pinzari, Flavia; Lo Papa, Giuseppe; Vittori Antisari, Livia; Vendramin, Elisa; Salvati, Luca; Dazzi, Carmelo; Benedetti, Anna

    2017-04-01

    Soils preserve and sustain life. Their health and functioning are crucial for crop production and for the maintenance of major ecosystem services. Human induced salinity is one of the main soil threats that reduces soil fertility and affect crop yields. In recent times, great attention has been paid to the general shortage of arable land and to the increasing demand for ecological restoration of areas affected by salinization processes. Despite the diffuse interest on the effects of salinization on plants' growth, and all the derived socioeconomic issues, very few studies analyzed the ecology of the microbial species in naturally saline soils and the resilience of biological fertility in these extreme habitats. Microorganisms inhabiting such environments may share a strategy, may have developed multiple adaptations for maintaining their populations, and cope eventually to extreme conditions by altruistic or cooperative behaviors for maintaining their metabolism active. The understanding and the knowledge of the composition and distribution of microbial communities in natural hypersaline soils can be interesting for ecological reasons but also to develop new restoration strategy where soil fertility was compromised by natural accidents or human mismanagement. The aim of this research was to provide specific information on saline soils in Italy, stressing mainly their distribution, the socioeconomic issues and the understanding of the characterizing ecological processes. Moreover, natural saline soils were used as a model for understanding to what extent the concentration of salt can affect some basic microbial processes. In the present study, physical, chemical and microbiological soil properties were investigated in the shallower horizons of natural salt affected soils in Sicily (Italy), where some ecological contrasting variables acted as strong drivers in fungal and bacterial spatial distribution. Furthermore, the interface between biological and geochemical

  16. [A systematic review of international simulation models on the natural history of breast cancer: current understanding and challenges for Chinese-population-specific model development].

    Science.gov (United States)

    Ma, H M; Wang, L; Shi, J F; Ying, J M; Zhu, J; Chen, L L; Yue, X P; Gong, J Y; Li, X; Wang, J L; Dai, M

    2017-10-10

    Objective: To systematically review the worldwide simulation model studies on the natural history of breast cancer and to summarize related parameters. Methods: A structured literature search was conducted in PubMed and the Cochrane Library to identify articles during 1980-2015. Articles were screened independently by two researchers. Health states in the natural history and relevant parameters were extracted. Results: A total of 36 studies were included for analysis, within the earliest one was published in 1990. Most studies were from Europe and America countries, and 2 studies from China. Markov model was mostly applied to evaluating breast cancer screening programs ( n =32). Reported health status included "healthy" ( n =36), ductal carcinoma in situ (DCIS, n =17), invasive breast cancer (IBC, n =36), and death ( n =27). There were two definite classifications for IBC, tumor size ( n =9) and TNM staging ( n =9, 3 studies reported transition rates). The median (range) of annual transition rates from DCIS to stage-Ⅰ IBC, Ⅰ to Ⅱ, Ⅱ to Ⅲ, Ⅲ to Ⅳ were 0.279 (0.259-0.299), 0.150 (0.069-0.430), 0.100 (0.060-0.128) and 0.210 (0.010-0.625), respectively. A total of 15 studies reported the mean duration from predinical to clinical stage for IBC was 1.95-4.70 years, which gradually increased with age, and 7 studies reported that for DCIS. Conclusions: Despite closer attention was paid to breast cancer natural history models, in recent years atypical hyperplasia has been neglected. Data on the mean duration of DCIS requires reasonable conversion. Various classifications for IBC exist whereas transition rates are limited. Current findings would be valuable references but challenging for the Chinese-population specific natural history model, development.

  17. Forensic comparison and matching of fingerprints: using quantitative image measures for estimating error rates through understanding and predicting difficulty.

    Directory of Open Access Journals (Sweden)

    Philip J Kellman

    Full Text Available Latent fingerprint examination is a complex task that, despite advances in image processing, still fundamentally depends on the visual judgments of highly trained human examiners. Fingerprints collected from crime scenes typically contain less information than fingerprints collected under controlled conditions. Specifically, they are often noisy and distorted and may contain only a portion of the total fingerprint area. Expertise in fingerprint comparison, like other forms of perceptual expertise, such as face recognition or aircraft identification, depends on perceptual learning processes that lead to the discovery of features and relations that matter in comparing prints. Relatively little is known about the perceptual processes involved in making comparisons, and even less is known about what characteristics of fingerprint pairs make particular comparisons easy or difficult. We measured expert examiner performance and judgments of difficulty and confidence on a new fingerprint database. We developed a number of quantitative measures of image characteristics and used multiple regression techniques to discover objective predictors of error as well as perceived difficulty and confidence. A number of useful predictors emerged, and these included variables related to image quality metrics, such as intensity and contrast information, as well as measures of information quantity, such as the total fingerprint area. Also included were configural features that fingerprint experts have noted, such as the presence and clarity of global features and fingerprint ridges. Within the constraints of the overall low error rates of experts, a regression model incorporating the derived predictors demonstrated reasonable success in predicting objective difficulty for print pairs, as shown both in goodness of fit measures to the original data set and in a cross validation test. The results indicate the plausibility of using objective image metrics to predict expert

  18. Tackle-related injury rates and nature of injuries in South African Youth Week tournament rugby union players (under-13 to under-18): an observational cohort study

    NARCIS (Netherlands)

    Burger, N.; Lambert, M.I.; Viljoen, W.; Brown, J.; Readhead, C.; Hendricks, S.

    2014-01-01

    Objectives: The tackle situation is most often associated with the high injury rates in rugby union. Tackle injury epidemiology in rugby union has previously been focused on senior cohorts but less is known about younger cohorts. The aim of this study was to report on the nature and rates of

  19. Nature of rate-limiting steps in a compartmentalized enzyme system. Quantitation of dopamine transport and hydroxylation rates in resealed chromaffin granule ghosts

    International Nuclear Information System (INIS)

    Ahn, N.G.; Klinman, J.P.

    1989-01-01

    Using isolated chromaffin granule ghosts from bovine adrenal medullae, we have studied the kinetics of dopamine beta-monooxygenase (D beta M) activity as it is linked to dopamine transport. Measurements of the initial rates of transport and of transport-linked norepinephrine formation suggested that enzyme activity may be partially rate-limiting in the coupled carrier/enzyme system. This was confirmed by (i) measurements of initial rates of norepinephrine formation using deuterated substrate, which gave isotope effects greater than 2.0, and (ii) kinetic measurements using ghosts pulsed with varying concentrations of labeled dopamine, which indicated substantial substrate accumulation in the vesicle interior as a function of time. Initial rates of product formation, when combined with approximations of internal substrate concentrations, allowed estimates of Kcat and Km for intravesicular D beta M. Activation by external reductant was apparent in both initial rate parameters and the measurements of transients. Under conditions of optimal D beta M activity, the enzyme rate parameters (kcat = 0.31 nmol/s.mg and Km = 2 mM) indicated partial rate limitation compared to dopamine transport (kcat = 0.38 nmol/s.mg and Km = 32 microM). Compartmental analysis of the time curves, performed using numerical nonlinear least squares methods, gave least squares estimates of rate constants for a simple carrier mechanism and kcat values for D beta M which were consistent with estimates from initial rates

  20. Bridging Human and Natural Sciences for a Better Understanding of Urban Floral Patterns: the Role of Planting Practices in Mediterranean Gardens

    Directory of Open Access Journals (Sweden)

    Audrey Marco

    2010-06-01

    Full Text Available Biodiversity research in urban settings constitutes an interdisciplinary field combining both the natural and human sciences. A full understanding of the patterns and processes underlying the dynamic of biodiversity in urban ecosystems needs to include humans in models of ecological functioning. We focus on the planting practices of gardeners to identify the bottom-up and top-down human influences on the floral diversity of the Mediterranean gardens in an urbanizing rural zone. An initial ecological study of cultivated flora in 120 private gardens showing floristic pattern variations along an urbanization gradient was combined with a sociological survey. This survey aimed at collecting reasons for planting in gardens in connection with cultivated species. These reasons were classified into categories and analyzed according to the frequency of cultivated species within the entire gradient. Floristic heterogeneity in gardens, represented by the richness of uncommon species, is predominantly caused by social factors, particularly related to the practices and social networks of gardeners who tend to diversify the range of species that are planted. Floristic uniformity, defined by a high frequency of occurrence of plant species, results not only from social factors but also from natural factors that exert high pressure in the Mediterranean region. This "floristic norm" is also influenced by the urban context, which can modify the expression of natural and social factors and lead to differences in plant species compositions between housing density zones. More generally, these results stress the importance of considering both individual choices and city-level influences through an interdisciplinary approach to understanding the underlying processes that establish urban biodiversity patterns at a small scale.

  1. Effects of Jigsaw Cooperative Learning and Animation Techniques on Students' Understanding of Chemical Bonding and Their Conceptions of the Particulate Nature of Matter

    Science.gov (United States)

    Karacop, Ataman; Doymus, Kemal

    2013-04-01

    The aim of this study was to determine the effect of jigsaw cooperative learning and computer animation techniques on academic achievements of first year university students attending classes in which the unit of chemical bonding is taught within the general chemistry course and these students' learning of the particulate nature of matter of this unit. The sample of this study consisted of 115 first-year science education students who attended the classes in which the unit of chemical bonding was taught in a university faculty of education during the 2009-2010 academic year. The data collection instruments used were the Test of Scientific Reasoning, the Purdue Spatial Visualization Test: Rotations, the Chemical Bonding Academic Achievement Test, and the Particulate Nature of Matter Test in Chemical Bonding (CbPNMT). The study was carried out in three different groups. One of the groups was randomly assigned to the jigsaw group, the second was assigned to the animation group (AG), and the third was assigned to the control group, in which the traditional teaching method was applied. The data obtained with the instruments were evaluated using descriptive statistics, one-way ANOVA, and MANCOVA. The results indicate that the teaching of chemical bonding via the animation and jigsaw techniques was more effective than the traditional teaching method in increasing academic achievement. In addition, according to findings from the CbPNMT, the students from the AG were more successful in terms of correct understanding of the particulate nature of matter.

  2. Understanding the nature of change

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe

    2016-01-01

    This article argues that core lines of sociological institutionalist thought provide a set of valuable conceptual and theoretical vocabularies for exploring and explaining contemporary concerns of development cooperation. It identi es four broad categories of issues of central attention in the cu...

  3. The effect of natural antioxidants on the rate of accumulation of oxidation products in the fat phase of butter cream

    Directory of Open Access Journals (Sweden)

    M. S. Voronina

    2016-01-01

    Full Text Available Describes the main finishing prefabricated pastries and cakes-cream. Researched range of cream depending on the fruit components and method of production. Aim: to study the degree of oxidation cream with natural antioxidants from fruits and berries processing products, namely in the form of concentrated juice of fruits and berries. Outlines the process of oxidation of lipids, one of the fundamental processes of loss of quality food products. Describes the action of antioxidants as antioxidants on accumulation intensity concentrations of primary and secondary oxidation products, making the final product unsuitable for the consumer and the bounding its shelf life. Presents the results of a study of the contents of primary and secondary oxidation products in butter cream immediately after cooking, as well as samples, stored for five days with the addition of antioxidants in the form of concentrated juice of fruits and berries in the amount of 2–7% by weight of cream. As a control sample has been used cream with no additives. Quality indicators to characterize the degree of oxidation of the product: acid, peroxide, anizidin and tioburbit number. The study found that adding a concentrated juice of fruits and berries as antioxidant in recipe cream reduces the growth rate of the concentration of free fatty acids on the fifth day, as compared with the reference sample. Adding concentrated juice of fruits and berries slows down the process of dissolution of the fat molecules in fat fraction of cream with the formation of free fatty acids; intensity decay reaction of peroxides and hydroxides slows down and, consequently, decreases the formation of aldehydes, deteriorating the taste and smell of the cream; quantitatively reduced the growth of education malondial′degida.

  4. Weakly Deleterious Mutations and Low Rates of Recombination Limit the Impact of Natural Selection on Bacterial Genomes.

    Science.gov (United States)

    Price, Morgan N; Arkin, Adam P

    2015-12-15

    Free-living bacteria are usually thought to have large effective population sizes, and so tiny selective differences can drive their evolution. However, because recombination is infrequent, "background selection" against slightly deleterious alleles should reduce the effective population size (Ne) by orders of magnitude. For example, for a well-mixed population with 10(12) individuals and a typical level of homologous recombination (r/m = 3, i.e., nucleotide changes due to recombination [r] occur at 3 times the mutation rate [m]), we predict that Ne is higher than diversity within a subpopulation, which makes it difficult to estimate Ne correctly. Given an estimate of Ne, standard population genetics models imply that selection should be sufficient to drive evolution if Ne × s is >1, where s is the selection coefficient. We found that this remains approximately correct if background selection is occurring or when population structure is present. Overall, we predict that even for free-living bacteria with enormous populations, natural selection is only a significant force if s is above 10(-7) or so. Because bacteria form huge populations with trillions of individuals, the simplest theoretical prediction is that the better allele at a site would predominate even if its advantage was just 10(-9) per generation. In other words, virtually every nucleotide would be at the local optimum in most individuals. A more sophisticated theory considers that bacterial genomes have millions of sites each and selection events on these many sites could interfere with each other, so that only larger effects would be important. However, bacteria can exchange genetic material, and in principle, this exchange could eliminate the interference between the evolution of the sites. We used simulations to confirm that during multisite evolution with realistic levels of recombination, only larger effects are important. We propose that advantages of less than 10(-7) are effectively neutral

  5. Errors in identification using natural markings : Rates, sources, and effects on capture-recapture estimates of abundance

    NARCIS (Netherlands)

    Stevick, PT; Palsboll, PJ; Smith, TD; Bravington, MV; Hammond, PS

    The results of a double-marking experiment using natural markings and microsatellite genetic markers to identify humpback whales (Megaptera novaeangliae) confirm that natural markings are a reliable means of identifying individuals on a large scale. Of 1410 instances of double tagging, there were

  6. Pollutant Concentrations and Emission Rates from Scripted Natural Gas Cooking Burner Use in Nine Northern California Homes

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lorenzetti, David M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Maddalena, Randy L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-10-01

    in the kitchen and bedroom of several homes. A hood with large capture volume and a measured flow of 108 L/s reduced concentrations 80-95%. IMPLICATIONS: These measurements demonstrate that operation of natural gas cooking burners without venting can cause short-term kitchen concentrations of NO2 to exceed the US outdoor health standard, and can elevate concentrations of NO, NO2, and ultrafine particles throughout the home. Results are generally consistent with a recent simulation study that estimated widespread 1h NO2 exposures exceeding 100 ppb in homes that use gas burners without venting. While operating a venting range hood can greatly reduce pollutant levels from burner use (and presumably from cooking as well), performance varies widely across hoods. Increased awareness of the need to ventilate when cooking would substantially reduce in-home exposure to NO2 and ultrafine particles in California homes. Helping consumers select effective hoods, for example by publishing capture efficiency performance ratings, also would help reduce exposure.

  7. Understanding the natural and social factors behind regional longevity in Guangxi, China—Is centenarian ratio a good enough indicator for assessing the longevity level?

    Science.gov (United States)

    Deng, Q.; Wei, Y.; Zhao, Y.

    2017-12-01

    Despite a number of longevity indicators having been used in previous longevity studies, few studies have critically evaluated whether these indicators are suitable. In addition, an increasing number of studies have attempted to determine the influence of socio-economic and natural factors on regional longevity, but only certain factors were considered. The present study bridges this gap by determining the relationship between the seven longevity indicators and selecting 24 natural and socio-economic indicators in the 91 selected counties and districts in Guangxi, China. The seven longevity indicators here refer to Centenarian ratio, Longevity index, Longevity level, Aging tendency, 80+ ratio, 90+ ratio and 95+ ratio. Natural indicators in this study mainly refer to climatic ones. Socio-economic indicators can be categorized into those related to economic, education, local infrastructure, and health care facilities. These data were mainly drawn from the Meteorological Data Sharing Service System and Guangxi's sixth population census. Stepwise regression analysis has been used as the primary research method to determine the relationship between the longevity indicators and the natural, social, and economic indicators. The results show that the climate factors regarding atmospheric pressure, humidity, and rainfall are the most significant contributors to the longevity of the 60- to 90-year-old elderly in Guangxi, while the difference of mean annual temperature could have negative impacts. Also, the natural and socioeconomic factors that impact the extremely old population (those over 95 years old) in Guangxi are still not clear. This study reveals that the longevity index and longevity level are useful supplementary indexes to the centenarian ratio for assessing the regional longevity as they could help reflect the regional longevity regarding the proportion of young-old and old-old population and not just limit to those over 100 years old. The elderly (those from 60

  8. Evaluating the predictive performance of empirical estimators of natural mortality rate using information on over 200 fish species

    Science.gov (United States)

    Then, Amy Y.; Hoenig, John M; Hall, Norman G.; Hewitt, David A.

    2015-01-01

    Many methods have been developed in the last 70 years to predict the natural mortality rate, M, of a stock based on empirical evidence from comparative life history studies. These indirect or empirical methods are used in most stock assessments to (i) obtain estimates of M in the absence of direct information, (ii) check on the reasonableness of a direct estimate of M, (iii) examine the range of plausible M estimates for the stock under consideration, and (iv) define prior distributions for Bayesian analyses. The two most cited empirical methods have appeared in the literature over 2500 times to date. Despite the importance of these methods, there is no consensus in the literature on how well these methods work in terms of prediction error or how their performance may be ranked. We evaluate estimators based on various combinations of maximum age (tmax), growth parameters, and water temperature by seeing how well they reproduce >200 independent, direct estimates of M. We use tenfold cross-validation to estimate the prediction error of the estimators and to rank their performance. With updated and carefully reviewed data, we conclude that a tmax-based estimator performs the best among all estimators evaluated. The tmax-based estimators in turn perform better than the Alverson–Carney method based on tmax and the von Bertalanffy K coefficient, Pauly’s method based on growth parameters and water temperature and methods based just on K. It is possible to combine two independent methods by computing a weighted mean but the improvement over the tmax-based methods is slight. Based on cross-validation prediction error, model residual patterns, model parsimony, and biological considerations, we recommend the use of a tmax-based estimator (M=4.899tmax−0.916">M=4.899t−0.916maxM=4.899tmax−0.916, prediction error = 0.32) when possible and a growth-based method (M=4.118K0.73L∞−0.33">M=4.118K0.73L−0.33∞M=4.118K0.73L∞−0.33 , prediction error

  9. Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: a spatio-temporal framework for understanding water management impacts

    Science.gov (United States)

    Condon, Laura E.; Maxwell, Reed M.

    2014-03-01

    Regional scale water management analysis increasingly relies on integrated modeling tools. Much recent work has focused on groundwater-surface water interactions and feedbacks. However, to our knowledge, no study has explicitly considered impacts of management operations on the temporal dynamics of the natural system. Here, we simulate twenty years of hourly moisture dependent, groundwater-fed irrigation using a three-dimensional, fully integrated, hydrologic model (ParFlow-CLM). Results highlight interconnections between irrigation demand, groundwater oscillation frequency and latent heat flux variability not previously demonstrated. Additionally, the three-dimensional model used allows for novel consideration of spatial patterns in temporal dynamics. Latent heat flux and water table depth both display spatial organization in temporal scaling, an important finding given the spatial homogeneity and weak scaling observed in atmospheric forcings. Pumping and irrigation amplify high frequency (sub-annual) variability while attenuating low frequency (inter-annual) variability. Irrigation also intensifies scaling within irrigated areas, essentially increasing temporal memory in both the surface and the subsurface. These findings demonstrate management impacts that extend beyond traditional water balance considerations to the fundamental behavior of the system itself. This is an important step to better understanding groundwater’s role as a buffer for natural variability and the impact that water management has on this capacity.

  10. Engaging Students in Authentic Microbiology Research in an Introductory Biology Laboratory Course is Correlated with Gains in Student Understanding of the Nature of Authentic Research and Critical Thinking

    Directory of Open Access Journals (Sweden)

    Brittany J. Gasper

    2013-02-01

    Full Text Available Recent recommendations for biology education highlight the role of authentic research experiences early in undergraduate education as a means of increasing the number and quality of biology majors. These experiences will inform students on the nature of science, increase their confidence in doing science, as well as foster critical thinking skills, an area that has been lacking despite it being one of the desired outcomes at undergraduate institutions and with future employers. With these things in mind, we have developed an introductory biology laboratory course where students design and execute an authentic microbiology research project. Students in this course are assimilated into the community of researchers by engaging in scholarly activities such as participating in inquiry, reading scientific literature, and communicating findings in written and oral formats. After three iterations of a semester-long laboratory course, we found that students who took the course showed a significant increase in their understanding of the nature of authentic research and their level of critical thinking skills.

  11. Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: a spatio-temporal framework for understanding water management impacts

    International Nuclear Information System (INIS)

    Condon, Laura E; Maxwell, Reed M

    2014-01-01

    Regional scale water management analysis increasingly relies on integrated modeling tools. Much recent work has focused on groundwater–surface water interactions and feedbacks. However, to our knowledge, no study has explicitly considered impacts of management operations on the temporal dynamics of the natural system. Here, we simulate twenty years of hourly moisture dependent, groundwater-fed irrigation using a three-dimensional, fully integrated, hydrologic model (ParFlow-CLM). Results highlight interconnections between irrigation demand, groundwater oscillation frequency and latent heat flux variability not previously demonstrated. Additionally, the three-dimensional model used allows for novel consideration of spatial patterns in temporal dynamics. Latent heat flux and water table depth both display spatial organization in temporal scaling, an important finding given the spatial homogeneity and weak scaling observed in atmospheric forcings. Pumping and irrigation amplify high frequency (sub-annual) variability while attenuating low frequency (inter-annual) variability. Irrigation also intensifies scaling within irrigated areas, essentially increasing temporal memory in both the surface and the subsurface. These findings demonstrate management impacts that extend beyond traditional water balance considerations to the fundamental behavior of the system itself. This is an important step to better understanding groundwater’s role as a buffer for natural variability and the impact that water management has on this capacity. (paper)

  12. Understanding the Low Photosynthetic Rates of Sun and Shade Coffee Leaves: Bridging the Gap on the Relative Roles of Hydraulic, Diffusive and Biochemical Constraints to Photosynthesis

    Science.gov (United States)

    Martins, Samuel C. V.; Galmés, Jeroni; Cavatte, Paulo C.; Pereira, Lucas F.; Ventrella, Marília C.; DaMatta, Fábio M.

    2014-01-01

    It has long been held that the low photosynthetic rates (A) of coffee leaves are largely associated with diffusive constraints to photosynthesis. However, the relative limitations of the stomata and mesophyll to the overall diffusional constraints to photosynthesis, as well as the coordination of leaf hydraulics with photosynthetic limitations, remain to be fully elucidated in coffee. Whether the low actual A under ambient CO2 concentrations is associated with the kinetic properties of Rubisco and high (photo)respiration rates also remains elusive. Here, we provide a holistic analysis to understand the causes associated with low A by measuring a variety of key anatomical/hydraulic and photosynthetic traits in sun- and shade-grown coffee plants. We demonstrate that leaf hydraulic architecture imposes a major constraint on the maximisation of the photosynthetic gas exchange of coffee leaves. Regardless of the light treatments, A was mainly limited by stomatal factors followed by similar limitations associated with the mesophyll and biochemical constraints. No evidence of an inefficient Rubisco was found; rather, we propose that coffee Rubisco is well tuned for operating at low chloroplastic CO2 concentrations. Finally, we contend that large diffusive resistance should lead to large CO2 drawdown from the intercellular airspaces to the sites of carboxylation, thus favouring the occurrence of relatively high photorespiration rates, which ultimately leads to further limitations to A. PMID:24743509

  13. Predators and predation rates of skylark Alauda arvensis and woodlark Lullula arborea nests in a semi-natural area in the Netherlands

    NARCIS (Netherlands)

    Praus, Libor; Hegemann, Arne; Tieleman, B. Irene; Weidinger, Karel

    2014-01-01

    Predation is a major cause of breeding failure in bird species with open nests. Although many studies have investigated nest predation rates, direct identification of nest predators is sporadic, especially in (semi-)natural habitats. We quantified nest success and identified nest predators in a

  14. Race-specific impact of natural history, mammography screening, and adjuvant treatment on breast cancer mortality rates in the United States

    NARCIS (Netherlands)

    N.T. van Ravesteyn (Nicolien); C.B. Schechter (Clyde); A.M. Near (Aimee); E.A.M. Heijnsdijk (Eveline); M.A. Stoto (Michael); G. Draisma (Gerrit); H.J. de Koning (Harry); J.S. Mandelblatt (Jeanne)

    2011-01-01

    textabstractBackground: U.S. Black women have higher breast cancer mortality rates than White women despite lower incidence. The aim of this study is to investigate how much of the mortality disparity can be attributed to racial differences in natural history, uptake of mammography screening, and

  15. Understanding the interaction between henipaviruses and their natural host, fruit bats: Paving the way toward control of highly lethal infection in humans.

    Science.gov (United States)

    Enchéry, François; Horvat, Branka

    2017-03-04

    Hendra virus and Nipah virus (NiV) are highly pathogenic zoonotic paramyxoviruses, from henipavirus genus, that have emerged in late 1990s in Australia and South-East Asia, respectively. Since their initial identification, numerous outbreaks have been reported, affecting both domestic animals and humans, and multiple rounds of person-to-person NiV transmission were observed. Widely distributed fruit bats from Pteropodidae family were found to be henipavirus natural reservoir. Numerous studies have reported henipavirus seropositivity in pteropid bats, including bats in Africa, thus expanding notably the geographic distribution of these viruses. Interestingly, henipavirus infection in bats seems to be asymptomatic, in contrast to severe disease induced in numerous other mammals. Unique among the mammals by their ability to fly, these intriguing animals are natural reservoir for many other emerging and remerging viruses highly pathogenic for humans. This feature, combined with absence of clinical symptoms, has attracted the interest of scientific community to virus-bat interactions. Therefore, several bat genomes were sequenced and particularities of the bat immune system have been intensively analyzed during the last decade to understand their coexistence with viruses in the absence of disease. The peculiarities in inflammasome activation, a constitutive expression of interferon alpha, and some differences in adaptive immunity have been recently reported in fruit bats. Studies on virus-bat interactions have thus emerged as an exciting novel area of research that should shed new light on the mechanisms that regulate viral infection and may allow development of novel therapeutic approaches to control this highly lethal emerging infectious disease in humans.

  16. With hiccups and bumps: the development of a Rasch-based instrument to measure elementary students' understanding of the nature of science.

    Science.gov (United States)

    Peoples, Shelagh M; O'Dwyer, Laura M; Shields, Katherine A; Wang, Yang

    2013-01-01

    This research describes the development process, psychometric analyses and part validation study of a theoretically-grounded Rasch-based instrument, the Nature of Science Instrument-Elementary (NOSI-E). The NOSI-E was designed to measure elementary students' understanding of the Nature of Science (NOS). Evidence is provided for three of the six validity aspects (content, substantive and generalizability) needed to support the construct validity of the NOSI-E. A future article will examine the structural and external validity aspects. Rasch modeling proved especially productive in scale improvement efforts. The instrument, designed for large-scale assessment use, is conceptualized using five construct domains. Data from 741 elementary students were used to pilot the Rasch scale, with continuous improvements made over three successive administrations. The psychometric properties of the NOSI-E instrument are consistent with the basic assumptions of Rasch measurement, namely that the items are well-fitting and invariant. Items from each of the five domains (Empirical, Theory-Laden, Certainty, Inventive, and Socially and Culturally Embedded) are spread along the scale's continuum and appear to overlap well. Most importantly, the scale seems appropriately calibrated and responsive for elementary school-aged children, the target age group. As a result, the NOSI-E should prove beneficial for science education research. As the United States' science education reform efforts move toward students' learning science through engaging in authentic scientific practices (NRC, 2011), it will be important to assess whether this new approach to teaching science is effective. The NOSI-E can be used as one measure of whether this reform effort has an impact.

  17. Synthesizing the Use of Carbon Isotope (14C and 13C) Approaches to Understand Rates and Pathways for Permafrost C Mobilization and Mineralization

    Science.gov (United States)

    Estop-Aragones, C.; Olefeldt, D.; Schuur, E.

    2015-12-01

    To better understand the permafrost carbon (C) feedback it is important to synthesize our current knowledge, and knowledge gaps, of how permafrost thaw can cause in situ mineralization or downstream mobilization of aged soil organic carbon (SOC) and the rate of this release. This potential loss of old SOC may occur via gaseous flux of CO2 and CH4 exchanged between soil and the atmosphere and via waterborne flux as DOC, POC (and their subsequent decomposition and release to the atmosphere). Carbon isotope (14C and 13C) approaches have been used to estimate both rates and pathways for permafrost C mobilization and mineralization. Radiocarbon (14C) has been used to estimate the contribution of aged C to overall respiration or waterborne C export. We aim to contrast results from radiocarbon studies, in order to assess differences between ecosystems (contrasting wet and dry ecosystems), thaw histories (active layer deepening or thermokarst landforms), greenhouse gas considered (CO2 and CH4) and seasons. We propose to also contrast methodologies used for assessing the contribution of aged C to overall C balance, and include studies using 13C data. Biological fractionation of 13C during both uptake and decomposition has been taken advantage of both in order to aid the interpretation of 14C data and on its own to assess sources and mineralization pathways. For example, 13C data has been used to differentiate between CH4 production pathways, and the relative contribution of anaerobic CO2 production to overall respiration. Overall, carbon isotope research is proving highly valuable for our understanding of permafrost C dynamics following thaw, and there is a current need to synthesize the available literature.

  18. Establishment of native species on a natural gas pipeline: the importance of seeding rate, aspect, and species selection

    Science.gov (United States)

    Melissa A. Thomas-Van Gundy; Pamela J. Edwards; Thomas M. Schuler

    2018-01-01

    With the increase in natural gas production in the United States, land managers need solutions and best practices to mitigate potential negative impacts of forest and soil disturbance and meet landowner objectives and desired conditions. Mitigation often includes the use of native seed mixes for maintaining plant diversity, controlling nonnative invasive species, and...

  19. Preimplantation Genetic Diagnosis and Natural Conception: A Comparison of Live Birth Rates in Patients with Recurrent Pregnancy Loss Associated with Translocation.

    Directory of Open Access Journals (Sweden)

    Shinichiro Ikuma

    Full Text Available Established causes of recurrent pregnancy loss (RPL include antiphospholipid syndrome, uterine anomalies, parental chromosomal abnormalities, particularly translocations, and abnormal embryonic karyotypes. The number of centers performing preimplantation genetic diagnosis (PGD for patients with translocations has steadily increased worldwide. The live birth rate with PGD was reported to be 27-54%. The live birth rate with natural conception was reported to be 37-63% on the first trial and 65-83% cumulatively. To date, however, there has been no cohort study comparing age and the number of previous miscarriages in matched patients undergoing or not undergoing PGD. Thus, we compared the live birth rate of patients with RPL associated with a translocation undergoing PGD with that of patients who chose natural conception.After genetic counseling, 52 patients who desired natural conception and 37 patients who chose PGD were matched for age and number of previous miscarriages and these comprised the subjects of our study. PGD was performed by means of fluorescence in situ hybridization analysis. The live birth rates on the first PGD trial and the first natural pregnancy after ascertainment of the carrier status were 37.8% and 53.8%, respectively (odds ratio 0.52, 95% confidence interval 0.22-1.23. Cumulative live birth rates were 67.6% and 65.4%, respectively, in the groups undergoing and not undergoing PGD. The time required to become pregnancy was similar in both groups. PGD was found to reduce the miscarriage rate significantly. The prevalence of twin pregnancies was significantly higher in the PGD group. The cost of PGD was $7,956 U.S. per patient.While PGD significantly prevented further miscarriages, there was no difference in the live birth rate. Couples should be fully informed of the similarity in the live birth rate, the similarity in time to become pregnancy, the advantages of PGD, such as the reduction in the miscarriage rate, as well as

  20. A long-term comparison of carbon sequestration rates in impounded and naturally tidal freshwater marshes along the lower Waccamaw River, South Carolina

    Science.gov (United States)

    Drexler, Judith Z.; Krauss, Ken W.; Sasser, M. Craig; Fuller, Christopher C.; Swarzenski, Christopher M.; Powell, Amber; Swanson, Kathleen M.; Orlando, James L.

    2013-01-01

    Carbon storage was compared between impounded and naturally tidal freshwater marshes along the Lower Waccamaw River in South Carolina, USA. Soil cores were collected in (1) naturally tidal, (2) moist soil (impounded, seasonally drained since ~1970), and (3) deeply flooded “treatments” (impounded, flooded to ~90 cm since ~2002). Cores were analyzed for % organic carbon, % total carbon, bulk density, and 210Pb and 137Cs for dating purposes. Carbon sequestration rates ranged from 25 to 200 g C m−2 yr−1 (moist soil), 80–435 g C m−2 yr−1 (naturally tidal), and 100–250 g C m−2 yr−1 (deeply flooded). The moist soil and naturally tidal treatments were compared over a period of 40 years. The naturally tidal treatment had significantly higher carbon storage (mean = 219 g C m−2 yr−1 vs. mean = 91 g C m−2 yr−1) and four times the vertical accretion rate (mean = 0.84 cm yr−1 vs. mean = 0.21 cm yr−1) of the moist soil treatment. The results strongly suggest that the long drainage period in moist soil management limits carbon storage over time. Managers across the National Wildlife Refuge system have an opportunity to increase carbon storage by minimizing drainage in impoundments as much as practicable.

  1. Teaching Teaching & Understanding Understanding

    DEFF Research Database (Denmark)

    2006-01-01

    "Teaching Teaching & Understanding Understanding" is a 19-minute award-winning short-film about teaching at university and higher-level educational institutions. It is based on the "Constructive Alignment" theory developed by Prof. John Biggs. The film delivers a foundation for understanding what...

  2. Geochemical and isotopic evidences from groundwater and surface water for understanding of natural contamination in chronic kidney disease of unknown etiology (CKDu) endemic zones in Sri Lanka.

    Science.gov (United States)

    Edirisinghe, E A N V; Manthrithilake, H; Pitawala, H M T G A; Dharmagunawardhane, H A; Wijayawardane, R L

    2017-09-26

    Chronic kidney disease of unknown etiology (CKDu) is the main health issue in the dry zone of Sri Lanka. Despite many studies carried out, causative factors have not been identified yet clearly. According to the multidisciplinary researches carried out so far, potable water is considered as the main causative factor for CKDu. Hence, the present study was carried out with combined isotopic and chemical methods to understand possible relationships between groundwater; the main drinking water source, and CKDu in four endemic areas in the dry zone. Different water sources were evaluated isotopically ( 2 H, 3 H and 18 O) and chemically from 2013 to 2015. Results revealed that prevalence of CKDu is significantly low with the groundwater replenished by surface water inputs. It is significantly high with the groundwater stagnated as well as groundwater recharged from regional flow paths. Thus, the origin, recharge mechanism and flow pattern of groundwater, as well as geological conditions which would be responsible for natural contamination of groundwater appear as the main causative factors for CKDu. Therefore, detailed investigations should be made in order to identify the element(s) in groundwater contributing to CKDu. The study recommends providing drinking water to the affected zones using water sources associated with surface waters.

  3. Low-dose natural prostaglandin F2α (dinoprost) at timed insemination improves conception rate in dairy cattle.

    Science.gov (United States)

    Ambrose, Divakar J; Gobikrushanth, Mohanathas; Zuidhof, Sjoert; Kastelic, John P

    2015-03-01

    The primary objective was to determine if low doses of PGF2α (dinoprost) given intramuscularly (im) concurrent with timed artificial insemination (TAI) would improve conception rates in dairy cattle. A secondary objective was to determine if body condition score (BCS) and parity would influence conception rates, either independently or in interaction with PGF2α treatment. In experiment I, 307 lactating Holstein cows were randomly assigned to receive either 5-mg PGF2α im (PGF2α treated, n = 154) or 0-mg PGF2α (control, n = 153) at TAI (Day 0). Blood samples were obtained on Days -10, -3, 0, and 7 to determine plasma progesterone (P4) concentrations. Pregnancy was confirmed 30 to 32 days after insemination by transrectal ultrasonography. In experiment II, 451 cows were randomly assigned to receive either 10-mg PGF2α im (PGF2α treated, n = 226) or 0-mg PGF2α (control, n = 225) at TAI, and pregnancy was confirmed 45 to 50 days after TAI by palpation per rectum. Pregnancy data were analyzed by CATMOD (SAS). In experiment I, PGF2α treatment, BCS, and parity did not affect conception rate (35.7% vs. 37.0% for PGF2α treated vs. control; P > 0.05). However, in experiment II, conception rates were higher in cows given 10-mg PGF2α than those in control cows (45.8% vs. 36.0%; P conception rates. In summary, 5 mg of PGF2α given im concurrent with TAI failed to enhance conception rate in lactating dairy cows, whereas 10 mg of PGF2α significantly increased conception rate. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Dynamics of tsetse natural infection rates in the Mouhoun river, Burkina Faso, in relation with environmental factors.

    Science.gov (United States)

    Bouyer, Jérémy; Koné, Naférima; Bengaly, Zakaria

    2013-01-01

    In Burkina Faso, the cyclical vectors of African animal trypanosomoses (AAT) are riverine tsetse species, namely Glossina palpalis gambiensis Vanderplank (G.p.g.) and Glossina tachinoides Westwood (G.t.) (Diptera: Glossinidae). Experimental work demonstrated that environmental stress can increase the sensitivity of tsetse to trypanosome infection. Seasonal variations of the tsetse infection rates were monitored monthly over 17 months (May 2006-September 2007) in two sites (Douroula and Kadomba). In total, 1423 flies were dissected and the infection of the proboscis, middle intestine and salivary glands was noted. All the positive organs were analyzed using monospecific polymerase chain reaction (PCR) primers. To investigate the role of different environmental factors, fly infection rates were analyzed using generalized linear mixed binomial models using the species, sex, and monthly averages of the maximum, minimum and mean daily temperatures, rainfalls, Land Surface Temperature day (LSTd) and night (LSTn) as fixed effects and the trap position as a random effect. The overall infection rate was 10% from which the predominant species was T. congolense (7.6% of the flies), followed by T. vivax (2.2% of the flies). The best model (lowest AICc) for the global infection rates was the one with the maximum daily temperature only as fixed effect (p temperature and rainfalls as fixed effect, where the maximum daily temperature was the main effect (p rate of T. congolense was very high (94%), and G. t. harbored a higher maturation rate (p = 0.03). The results are discussed in view of former laboratory studies showing that temperature stress can increase the susceptibility of tsetse to trypanosomes, as well as the possibility to improve AAT risk mapping using satellite images.

  5. Dynamics of tsetse natural infection rates in the Mouhoun river, Burkina Faso, in relation with environmental factors

    Directory of Open Access Journals (Sweden)

    Jérémy eBouyer

    2013-08-01

    Full Text Available In Burkina Faso, the cyclical vectors of African animal trypanosomoses (AAT are riverine tsetse species, namely Glossina palpalis gambiensis Vanderplank (G.p.g. and Glossina tachinoides Westwood (G. t. (Diptera: Glossinidae. Experimental work demonstrated that environmental stress can increase the sensitivity of tsetse to trypanosome infection.Seasonal variations of the tsetse infection rates were monitored monthly over 17 months (May 2006-Sept 2007 in two sites (Douroula and Kadomba. In total, 1,423 flies were dissected and the infection of the proboscis, middle intestine and salivary glands was noted. All the positive organs were analyzed using monospecific polymerase chain reaction (PCR primers. To investigate the role of different environmental factors, fly infection rates were analyzed using generalized linear mixed binomial models using the species, sex, and monthly averages of the maximal, minimal and mean daily temperatures, rainfalls, Land Surface Temperature day (LSTd and night (LSTn as fixed effects and the trap position as a random effect.The overall infection rate was 10% from which the predominant species was T. congolense (7.6% of the flies, followed by T. vivax (2.2% of the flies. The best model (lowest AICc for the global infection rates was the one with the maximal daily temperature only as fixed effect (p<0.001. For T. congolense, the best model was the one with the tsetse species, sex, maximal daily temperature and rainfalls as fixed effect, where the maximal daily temperature was the main effect (p<0.001. The number of T. vivax infections was too low to allow the models to converge. The maturation rate of T. congolense was very high (94%, and G. t. harbored a higher maturation rate (p=0.03.The results are discussed in view of former laboratory studies showing that temperature stress can increase the susceptibility of tsetse to trypanosomes, as well as the possibility to improve AAT risk mapping using satellite images.

  6. COMPARISON OF NATURAL BACKGROUND DOSE RATES FOR RESIDENTS OF THE AMARGOSA VALLEY, NV, TO THOSE IN LEADVILLE, CO, AND THE STATES OF COLORADO AND NEVADA

    International Nuclear Information System (INIS)

    D. Moeller and L. C. Sun

    2006-01-01

    In the latter half of 2005, the U.S. Environmental Protection Agency (USEPA) published a Proposed Rule (40 CFR Part 197) for establishing a dose rate standard for limiting radionuclide releases from the proposed Yucca Mountain high-level radioactive waste repository during the time period from 10 4 to 10 6 years after closure. The proposed standard was based on the difference in the estimated total dose rate from natural background in the Amargosa Valley and the ''average annual background radiation'' for the State of Colorado. As defined by the USEPA, ''natural background radiation consists of external exposures from cosmic and terrestrial sources, and internal exposures from indoor exposures to naturally-occurring radon''. On the basis of its assessments, the USEPA estimated that the difference in the dose rate in the two identified areas was 3.5 mSv y -1 . The purpose of this review was to provide an independent evaluation and review of this estimate. One of the first observations was that, because site-specific dose rate measurements for the Amargosa Valley ''were not available'', the dose rates for various sources of natural background in that area, used by the USEPA in its assessment, were based on modifications of the average values for the State of Nevada. A second observation was that the conversion factor applied in estimating the dose rates due to exposures to indoor radon and its decay products was a factor of 2 higher than the currently accepted value. Further review revealed that site-specific data for many natural background sources in the Amargosa Valley were available. One particularly important observation was that about 91% of the residents of that area live in mobile homes which, due to their construction and design, have indoor radon concentrations comparable to, or less than, those outdoors. For that reason, alone, the USEPA estimate of the average dose rate for residents of the Amargosa Valley, due to indoor radon, was not valid. For purposes

  7. Modelling of the change in national exchange rate model depending on the economic parameters of a natural gas cogeneration system: Turkey case

    International Nuclear Information System (INIS)

    Inan, Aslan; Izgi, Ercan; Ay, Selim

    2009-01-01

    In this paper, to what extent a cogeneration system's fixed and variable costs and profits are affected from the exchange rate model implemented in the country is examined. An autoproductor system, as known, uses a part of its electrical energy production for its own requirements while selling the remaining energy to the regional energy corporation. As a function of the load factor and the fuel cost, the production cost and energy sale income of the system are influenced much by the exchange rate model of the country. A cost analysis of a natural gas cogeneration (autoproductor) system has been performed for the numerical application, based on the monetary program supported by the IMF commenced in January 2000. In order to investigate the effect of the change in exchange rate model (introducing the floating exchange rate model) on the fuel cost, both the characteristics of the IMF program and some various forecasting methods have been utilized

  8. Natural radioactivity in some building materials in Cuba and their contribution to the indoor gamma dose rate

    Energy Technology Data Exchange (ETDEWEB)

    Brigido Flores, Osvaldo; Barreras Caballero, Aldo A.; Montalvan Estrada, Alberto; Queipo Garcia, Maite [Ministerio de Ciencia, Tecnologia y Medio Ambiente, Camaguey (Cuba). Centro de Atencion a la Actividad Nuclear. Lab. de Vigilancia Radiologica Ambiental]. E-mail: sean@caonao.cmw.inf.cu; Zerquera, Juan Tomas [Ministerio de Ciencia, Tecnologia y Medio Ambiente, La Habana (Cuba). Agencia de Energia Nuclear. Centro de Proteccion y Higiene de las Radiaciones

    2001-07-01

    The natural radioactivity of some building materials commonly used in Cuba was measured by gamma spectrometry. Typical concentrations, so far encountered, are in the ranges: 47 to 2511 Bq.kg{sup -1} for {sup 40} K; 9 to 71 Bq.kg{sup -1} for {sup 226} Ra; and 2 to 38 Bq.kg{sup -1} for {sup 232} Th. The external gamma ray absorbed doses in indoor air, and the corresponding effective dose equivalents in a typical dwelling are presented in this work. (author)

  9. A natural variant of NAL1, selected in high-yield rice breeding programs, pleiotropically increases photosynthesis rate.

    Science.gov (United States)

    Takai, Toshiyuki; Adachi, Shunsuke; Taguchi-Shiobara, Fumio; Sanoh-Arai, Yumiko; Iwasawa, Norio; Yoshinaga, Satoshi; Hirose, Sakiko; Taniguchi, Yojiro; Yamanouchi, Utako; Wu, Jianzhong; Matsumoto, Takashi; Sugimoto, Kazuhiko; Kondo, Katsuhiko; Ikka, Takashi; Ando, Tsuyu; Kono, Izumi; Ito, Sachie; Shomura, Ayahiko; Ookawa, Taiichiro; Hirasawa, Tadashi; Yano, Masahiro; Kondo, Motohiko; Yamamoto, Toshio

    2013-01-01

    Improvement of leaf photosynthesis is an important strategy for greater crop productivity. Here we show that the quantitative trait locus GPS (GREEN FOR PHOTOSYNTHESIS) in rice (Oryza sativa L.) controls photosynthesis rate by regulating carboxylation efficiency. Map-based cloning revealed that GPS is identical to NAL1 (NARROW LEAF1), a gene previously reported to control lateral leaf growth. The high-photosynthesis allele of GPS was found to be a partial loss-of-function allele of NAL1. This allele increased mesophyll cell number between vascular bundles, which led to thickened leaves, and it pleiotropically enhanced photosynthesis rate without the detrimental side effects observed in previously identified nal1 mutants, such as dwarf plant stature. Furthermore, pedigree analysis suggested that rice breeders have repeatedly selected the high-photosynthesis allele in high-yield breeding programs. The identification and utilization of NAL1 (GPS) can enhance future high-yield breeding and provides a new strategy for increasing rice productivity.

  10. A study of 239Pu production rate in a water cooled natural uranium blanket mock-up of a fusion-fission hybrid reactor

    Science.gov (United States)

    Feng, Song; Liu, Rong; Lu, Xinxin; Yang, Yiwei; Xu, Kun; Wang, Mei; Zhu, Tonghua; Jiang, Li; Qin, Jianguo; Jiang, Jieqiong; Han, Zijie; Lai, Caifeng; Wen, Zhongwei

    2016-03-01

    The 239Pu production rate is important data in neutronics design for a natural uranium blanket of a fusion-fission hybrid reactor, and the accuracy and reliability should be validated by integral experiments. The distribution of 239Pu production rates in a subcritical natural uranium blanket mock-up was obtained for the first time with a D-T neutron generator by using an activation technique. Natural uranium foils were placed in different spatial locations of the mock-up, the counts of 277.6 keV γ-rays emitted from 239Np generated by 238U capture reaction were measured by an HPGe γ spectrometer, and the self-absorption of natural uranium foils was corrected. The experiment was analyzed using the Super Monte Carlo neutron transport code SuperMC2.0 with recent nuclear data of 238U from the ENDF/B-VII.0, ENDF/B-VII.1, JENDL-4.0u2, JEFF-3.2 and CENDL-3.1 libraries. Calculation results with the JEFF-3.2 library agree with the experimental ones best, and they agree within the experimental uncertainty in general with the average ratios of calculation results to experimental results (C/E) in the range of 0.93 to 1.01.

  11. Synanthropic triatomines (Hemiptera, Reduviidae) in the state of Pernambuco, Brazil: geographical distribution and natural Trypanosoma infection rates between 2006 and 2007.

    Science.gov (United States)

    Silva, Maria Beatriz Araújo; Barreto, Ana Virgínia Matos Sá; Silva, Helker Albuquerque da; Galvão, Cleber; Rocha, Dayse; Jurberg, José; Gurgel-Gonçalves, Rodrigo

    2012-02-01

    The present study shows a descriptive analysis of triatomine occurrence and its natural Trypanosoma infection rates in the state of Pernambuco, Brazil, between 2006 and 2007. Entomological data for the species, such as specimens captured in both intra and peridomiciles and natural infection index, were obtained via domiciliary capture in 147 municipalities from 11 Regional Managements of Health. The database was obtained from a sample of insects (100% infected and 20% non-infected) sent to the Central Laboratory of Pernambuco. A total of 18,029 triatomines were analyzed from 138 municipalities of the state. Triatoma pseudomaculata (35%), Triatoma brasiliensis (34%), and Panstrongylus lutzi (25%) were the most captured species. These species also showed a widespread geographical distribution in the state. Panstrongylus megistus, Triatoma petrocchiae, Triatoma melanocephala, Triatoma sordida, Rhodnius nasutus, Rhodnius neglectus, and Triatoma infestans showed more limited geographical distribution and lower relative abundance. The parasitological research showed that 8.8% of the triatomines were naturally infected with flagellates morphologically similar to Trypanosoma cruzi and 91.3% of them were captured inside houses in 113 municipalities. P. lutzi showed the highest rates of natural infection. After the control of T. infestans, synanthropic species, such as T. brasiliensis, T. pseudomaculata, and P. lutzi, maintain the risk of T. cruzi transmission to humans in the state of Pernambuco. These species are widely distributed, and infected specimens have been found inside houses. Thus, an enhanced surveillance and vector control of Chagas disease is recommended in Pernambuco.

  12. Synanthropic triatomines (Hemiptera, Reduviidae in the state of Pernambuco, Brazil: geographical distribution and natural Trypanosoma infection rates between 2006 and 2007

    Directory of Open Access Journals (Sweden)

    Maria Beatriz Araújo Silva

    2012-02-01

    Full Text Available INTRODUCTION: The present study shows a descriptive analysis of triatomine occurrence and its natural Trypanosoma infection rates in the state of Pernambuco, Brazil, between 2006 and 2007. METHODS: Entomological data for the species, such as specimens captured in both intra and peridomiciles and natural infection index, were obtained via domiciliary capture in 147 municipalities from 11 Regional Managements of Health. The database was obtained from a sample of insects (100% infected and 20% non-infected sent to the Central Laboratory of Pernambuco. RESULTS: A total of 18,029 triatomines were analyzed from 138 municipalities of the state. Triatoma pseudomaculata (35%, Triatoma brasiliensis (34%, and Panstrongylus lutzi (25% were the most captured species. These species also showed a widespread geographical distribution in the state. Panstrongylus megistus, Triatoma petrocchiae, Triatoma melanocephala, Triatoma sordida, Rhodnius nasutus, Rhodnius neglectus, and Triatoma infestans showed more limited geographical distribution and lower relative abundance. The parasitological research showed that 8.8% of the triatomines were naturally infected with flagellates morphologically similar to Trypanosoma cruzi and 91.3% of them were captured inside houses in 113 municipalities. P. lutzi showed the highest rates of natural infection. CONCLUSIONS: After the control of T. infestans, synanthropic species, such as T. brasiliensis, T. pseudomaculata, and P. lutzi, maintain the risk of T. cruzi transmission to humans in the state of Pernambuco. These species are widely distributed, and infected specimens have been found inside houses. Thus, an enhanced surveillance and vector control of Chagas disease is recommended in Pernambuco.

  13. A natural variant of NAL1, selected in high-yield rice breeding programs, pleiotropically increases photosynthesis rate

    OpenAIRE

    Takai, Toshiyuki; Adachi, Shunsuke; Taguchi-Shiobara, Fumio; Sanoh-Arai, Yumiko; Iwasawa, Norio; Yoshinaga, Satoshi; Hirose, Sakiko; Taniguchi, Yojiro; Yamanouchi, Utako; Wu, Jianzhong; Matsumoto, Takashi; Sugimoto, Kazuhiko; Kondo, Katsuhiko; Ikka, Takashi; Ando, Tsuyu

    2013-01-01

    Improvement of leaf photosynthesis is an important strategy for greater crop productivity. Here we show that the quantitative trait locus GPS (GREEN FOR PHOTOSYNTHESIS) in rice (Oryza sativa L.) controls photosynthesis rate by regulating carboxylation efficiency. Map-based cloning revealed that GPS is identical to NAL1 (NARROW LEAF1), a gene previously reported to control lateral leaf growth. The high-photosynthesis allele of GPS was found to be a partial loss-of-function allele of NAL1. This...

  14. Final Report Real Time Monitoring of Rates of Subsurface Microbial Activity Associated with Natural Attenuation and Electron Donor Availability

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R. [Univ. of Massachusetts, Amherst, MA (United States)

    2016-03-22

    The project was successful in developing new sensing technologies for monitoring rates of microbial activity in soils and sediments and also developed a novel proof-of-concept for monitoring the presence of bioavailable concentrations of a diversity of metabolites and toxic components in sedimentary environments. These studies led not only to publications in the peer-reviewed literature, but also two patent applications and a start-up company.

  15. The contagious nature of imprisonment: an agent-based model to explain racial disparities in incarceration rates.

    Science.gov (United States)

    Lum, Kristian; Swarup, Samarth; Eubank, Stephen; Hawdon, James

    2014-09-06

    We build an agent-based model of incarceration based on the susceptible-infected-suspectible (SIS) model of infectious disease propagation. Our central hypothesis is that the observed racial disparities in incarceration rates between Black and White Americans can be explained as the result of differential sentencing between the two demographic groups. We demonstrate that if incarceration can be spread through a social influence network, then even relatively small differences in sentencing can result in large disparities in incarceration rates. Controlling for effects of transmissibility, susceptibility and influence network structure, our model reproduces the observed large disparities in incarceration rates given the differences in sentence lengths for White and Black drug offenders in the USA without extensive parameter tuning. We further establish the suitability of the SIS model as applied to incarceration by demonstrating that the observed structural patterns of recidivism are an emergent property of the model. In fact, our model shows a remarkably close correspondence with California incarceration data. This work advances efforts to combine the theories and methods of epidemiology and criminology.

  16. Water Conservation: A Tool to Build Understanding, Service and Awareness about Natural Resources Linda Ruiz McCall, Katherine K. Ellins, and Bridget Cameron

    Science.gov (United States)

    McCall, L. R.; Ellins, K. K.; Cameron, B.

    2010-12-01

    Water is arguably our most important natural resource, essential for sustaining life on Earth; necessary to support agriculture and industry; and important for fisheries, power, navigation, and recreation. As world population increases and climate change brings about a redistribution of water and people across our planet, water resource management and conservation are increasingly important. Based on current population projections for Texas, about 85 percent of the state’s projected population will not have enough water by 2060 in drought conditions. Water conservation is critical for meeting the state’s long-term water needs. To that end, the Texas Water Development Board (TWDB) is engaged in a number of education and outreach programs. In this paper, we report on three TWDB educational campaigns. Water Exploration, a Web-based water resources education program for Texas high school students, Put Some Blue in Your Green School, a service learning project designed to promote interaction between schools and their local communities, and Water IQ: Know Your Water, a public awareness campaign for water conservation. Water Exploration uses a pedagogical approach called the Legacy Cycle to involve students in experiential, project-based learning to help them achieve a deeper understanding about water resources. It addresses the need for rigorous curriculum in a vitally important area for the new Texas high school Earth and Space Science Capstone course, as well as Environmental Systems, and Aquatic Science. The interdisciplinary nature of the curriculum encourages students to explore the connections between water resources and economics (water planning, water as a commodity), history (water affects human settlement and migration), and biology (water is essential for life; contaminated water affects living organisms). The ability to integrate information from different disciplines and weigh the perspectives of multiple experts is particularly important for solving the

  17. Behavioral patterns, parity rate and natural infection analysis in anopheline species involved in the transmission of malaria in the northeastern Brazilian Amazon region.

    Science.gov (United States)

    Barbosa, Ledayane Mayana Costa; Souto, Raimundo Nonato Picanço; Dos Anjos Ferreira, Ricardo Marcelo; Scarpassa, Vera Margarete

    2016-12-01

    The characterization of behavioral patterns allows a better understanding of the transmission dynamics and the design of more effective malaria vector control strategies. This study analyzed the behavioral patterns of the Anopheles species of the Coração district situated in the northeast of the Brazilian Amazon region. The behavioral patterns of the anopheline species were measured based on the 36 collection sites of this district from December 2010 to November 2011. Collections of four hours for three consecutive nights each month and four 12-h collections, comprising two in the rainy season and two in the dry season, were performed. Furthermore, to infer the anthropophily and zoophily indexes, four additional four-hour collections were performed. The samples were also evaluated for parity rate and natural infectivity for Plasmodium spp. A total of 1689 anophelines were captured, comprising of nine species and two subgenera (Nyssorhynchus - six species, and Anopheles - three species). Anopheles darlingi was the most abundant and widely distributed species in the area, followed by A. braziliensis and A.marajoara. Anopheles darlingi and A. marajoara were the only species present in the four collections of 12-h, but only A. darlingi showed activity throughout night. Anopheles darlingi was the most anthropophilic species (AI=0.40), but the zoophily index was higher (ZI=0.60), revealing an eclectic and opportunistic behavior. Of the six most frequent species, A. nuneztovari s.l. was the most zoophilic species (ZI=1.00). All captured species showed predominance towards biting in outdoor environments. Anopheles darlingi and A. braziliensis showed multimodal biting peaks, whereas A. marajoara revealed a stable pattern, with the biting peak after sunset. Using the PCR technique, no anopheline was found infected with the malaria parasite. Since A. darlingi and A. marajoara are recognized as important vectors in this region, the district of Coração may be considered as

  18. Predominant anthropogenic sources and rates of atmospheric mercury accumulation in southern Ontario recorded by peat cores from three bogs: comparison with natural "background" values (past 8000 years).

    Science.gov (United States)

    Givelet, Nicolas; Roos-Barraclough, Fiona; Shotyk, William

    2003-12-01

    Peat cores from three bogs in southern Ontario provide a complete, quantitative record of net rates of atmospheric Hg accumulation since pre-industrial times. For comparison with modern values, a peat core extending back 8000 years was used to quantify the natural variations in Hg fluxes for this region, and their dependence on climatic change and land use history. The net mercury accumulation rates were separated into "natural" and "excess" components by comparing the Hg/Br ratios of modern samples with the long-term, pre-anthropogenic average Hg/Br. The average background mercury accumulation rate during the pre-anthropogenic period (from 5700 years BC to 1470 AD) was 1.4 +/- 1.0 microg m(-2) per year (n = 197). The beginning of Hg contamination from anthropogenic sources dates from AD 1475 at the Luther Bog, corresponding to biomass burning for agricultural activities by Native North Americans. During the late 17th and 18th centuries, deposition of anthropogenic Hg was at least equal to that of Hg from natural sources. Anthropogenic inputs of Hg to the bogs have dominated continuously since the beginning of the 19th century. The maximum Hg accumulation rates decrease in the order Sifton Bog, in the City of London, Ontario (141 microg Hg m(-2) per year), Luther Bog in an agricultural region (89 microg Hg m(-2) per year), and Spruce Bog which is in a comparatively remote, forested region (54 microg Hg m(-2) per year). Accurate age dating of recent peat samples using the bomb pulse curve of 14C shows that the maximum rate of atmospheric Hg accumulation occurred during AD 1956 and 1959 at all sites. In these (modern) samples, the Hg concentration profiles resemble those of Pb, an element which is known to be immobile in peat bogs. The correlation between these two metals, together with sulfur, suggests that the predominant anthropogenic source of Hg (and Pb) was coal burning. While Hg accumulation rates have gone into strong decline since the late 1950's, Hg

  19. Mapping growth and mortality rates of crevice-dwelling organisms onto a perforated surface: The relevance of `cover' to the carrying capacity of natural and artificial habitats

    Science.gov (United States)

    Caddy, J. F.; Stamatopoulos, C.

    1990-07-01

    A theoretical basis is suggested for examining habitat limitations of artificial surfaces for population enhancement of crevice-dwelling, or territorial organisms such as reef fish or lobsters, that takes into account known growth and mortality rates. This approach is compared with the crevice frequency at size in a 'natural' substrate, which, it is assumed, corresponds to fractal expectation. With naturally dissected surfaces, fractal expectation predicts that crevice availability declines with size, so that a 'bottleneck', limits the population of larger-sized individuals, but that natural mortality, or rate of loss of individuals displaced from crevices, will also decline with age. The paper considers a surface perforated with circular niches of a limited number of discrete radii, distributed at random over a surface, without overlap, and considers what is the size frequency of hole radii needed to complete the life history of an infaunal organism with a given mortality and growth schedule, and a constant occupancy rate. Determining a priori crevice frequency at size before constructing an artificial surface, and for a given packing density, distributing the crevices over it in two dimensions, is referred to as 'mapping' the growth and mortality rates onto the surface. Sample calculations are described either for continuous recruitment or where recruitment occurs as a 'pulse' during a specific season, and subsequent cohort growth obeys a common scheduling. It is shown that fractal surfaces limit the production of larger individuals unless migration intervenes, but are more suitable for recruitment enhancement. Using units with a limited size range of perforations is biologically inefficient, and depends on natural recruitment elsewhere for stock replenishment by migration. These calculations are relevant to the design of artificial surfaces, throw light on mechanisms limiting productivity of dissected surfaces, and point to effects of individual niche size on

  20. Comparison of the Kinetic Rate Law Parameters for the Dissolution of Natural and Synthetic Autunite in the Presence of Aqueous Bicarbonate Ions

    Energy Technology Data Exchange (ETDEWEB)

    Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.; Idarraga, Melina; Lagos, Leonel; Tansel, Berrin

    2013-08-02

    Bicarbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, bicarbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous bicarbonate concentration to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate (0.0005-0.003 M) under the pH range of 6-11 and a temperature range of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release exhibited minimal dependency on temperature; but were strongly dependent on pH. Increasing aqueous bicarbonate concentrations afforded comparable increases in the rate of release of uranium. Most notably under low pH conditions the aqueous bicarbonate resulted in up to 370 fold increases in the rate of uranium release in relative to the rate of uranium release in the absence of bicarbonate. However, the effect of aqueous bicarbonate on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release.

  1. A natural variant of NAL1, selected in high-yield rice breeding programs, pleiotropically increases photosynthesis rate

    Science.gov (United States)

    Takai, Toshiyuki; Adachi, Shunsuke; Taguchi-Shiobara, Fumio; Sanoh-Arai, Yumiko; Iwasawa, Norio; Yoshinaga, Satoshi; Hirose, Sakiko; Taniguchi, Yojiro; Yamanouchi, Utako; Wu, Jianzhong; Matsumoto, Takashi; Sugimoto, Kazuhiko; Kondo, Katsuhiko; Ikka, Takashi; Ando, Tsuyu; Kono, Izumi; Ito, Sachie; Shomura, Ayahiko; Ookawa, Taiichiro; Hirasawa, Tadashi; Yano, Masahiro; Kondo, Motohiko; Yamamoto, Toshio

    2013-01-01

    Improvement of leaf photosynthesis is an important strategy for greater crop productivity. Here we show that the quantitative trait locus GPS (GREEN FOR PHOTOSYNTHESIS) in rice (Oryza sativa L.) controls photosynthesis rate by regulating carboxylation efficiency. Map-based cloning revealed that GPS is identical to NAL1 (NARROW LEAF1), a gene previously reported to control lateral leaf growth. The high-photosynthesis allele of GPS was found to be a partial loss-of-function allele of NAL1. This allele increased mesophyll cell number between vascular bundles, which led to thickened leaves, and it pleiotropically enhanced photosynthesis rate without the detrimental side effects observed in previously identified nal1 mutants, such as dwarf plant stature. Furthermore, pedigree analysis suggested that rice breeders have repeatedly selected the high-photosynthesis allele in high-yield breeding programs. The identification and utilization of NAL1 (GPS) can enhance future high-yield breeding and provides a new strategy for increasing rice productivity. PMID:23985993

  2. A refined protocol for calculating air flow rate of naturally-ventilated broiler barns based on co2 mass balance

    Directory of Open Access Journals (Sweden)

    Luciano Barreto-Mendes

    2014-01-01

    Full Text Available Este estudio se realizó para evaluar protocolos relativamente simples para el monitoreo de la tasa de ventilación (TV en instalaciones pecuarias con ventilación natural (ENV. Los protocolos de ensayo se aplicaron primero a una instalación de pollos de engorde mecánicamente ventilada (EMV, donde TV se estimó con mayor precisión y luego se utilizaron para calcular la TV en la ENV. Las concentraciones de CO2 se midieron con dos esquemas de muestreo diferentes: (S1 la media de las mediciones al interior y a lo largo de la longitud de la instalación a dos alturas de 0,5 m y 1,5 m del suelo; y (S2 igual que la anterior pero con las mediciones de concentración fueron realizadas únicamente a 0,5 m del suelo. La tasa de producción de CO2 metabólico dinámico de las aves se predijo con dos algoritmos diferentes: (A1 el mantenimiento constante durante los periodos de luz y oscuridad, y (A2 que varía con la actividad de los animales sobre una base horaria. Los resultados demostraron que la combinación de S2 con A1 o A2 presentó la mejor estimación de TV en el ENV.

  3. The natural emergence of the correlation between H2 and star formation rate surface densities in galaxy simulations

    Science.gov (United States)

    Lupi, Alessandro; Bovino, Stefano; Capelo, Pedro R.; Volonteri, Marta; Silk, Joseph

    2018-03-01

    In this study, we present a suite of high-resolution numerical simulations of an isolated galaxy to test a sub-grid framework to consistently follow the formation and dissociation of H2 with non-equilibrium chemistry. The latter is solved via the package KROME, coupled to the mesh-less hydrodynamic code GIZMO. We include the effect of star formation (SF), modelled with a physically motivated prescription independent of H2, supernova feedback and mass-losses from low-mass stars, extragalactic and local stellar radiation, and dust and H2 shielding, to investigate the emergence of the observed correlation between H2 and SF rate surface densities. We present two different sub-grid models and compare them with on-the-fly radiative transfer (RT) calculations, to assess the main differences and limits of the different approaches. We also discuss a sub-grid clumping factor model to enhance the H2 formation, consistent with our SF prescription, which is crucial, at the achieved resolution, to reproduce the correlation with H2. We find that both sub-grid models perform very well relative to the RT simulation, giving comparable results, with moderate differences, but at much lower computational cost. We also find that, while the Kennicutt-Schmidt relation for the total gas is not strongly affected by the different ingredients included in the simulations, the H2-based counterpart is much more sensitive, because of the crucial role played by the dissociating radiative flux and the gas shielding.

  4. Understanding unemployment

    OpenAIRE

    Guillaume Rocheteau

    2006-01-01

    Modern economists have built models of the labor market, which isolate the market’s key drivers and describe the way these interact to produce particular levels of unemployment. One of the most popular models used by macroeconomists today is the search-matching model of equilibrium unemployment. We explain this model, and show how it can be applied to understand the way various policies, such as unemployment benefits, taxes, or technological changes, can affect the unemployment rate.

  5. Analysing Cases in Technology and Design Education: How Could Designing and Making Technological Products Be a Vehicle for Enhancing Understanding of Natural Science Principles?

    Science.gov (United States)

    Hansen, Pal J. Kirkeby

    2009-01-01

    "Knowledge Promotion" is the recent curriculum for the Norwegian 10-year compulsory school. "Technology and Design" (ToD) is a new main subject area in Natural Science. ToD should be taught across the curriculum between Natural Science, Art and Crafts, and Mathematics. The main goal is that pupils should be able to plan,…

  6. To fully exert the important role of natural gas in building a modern energy security system in China: An understanding of China's National l3th Five-Year Plan for Natural Gas Development

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    2017-07-01

    Full Text Available Along with the introduction of 13th Five-Year Plans in succession for natural gas development programmed by governments at all levels and much more attention paid to haze governance by relevant departments, natural gas, as one of the major energy sources, has ushered in a strategic opportunity era. In view of this, based upon China's National 13th Five-Year Plan for Natural Gas Development formulated by the National Development and Reform Commission, the developing trend of natural gas sector was predicted in the period of 13th Five-Year Plan in terms of supply side, demand side, pricing system, infrastructure construction, etc. and some feasible proposals were made on the whole industrial chain. In terms of the supply side, natural gas will be of availability, accessibility, assurance, affordability, and accountability in the production and supply chains. In terms of the demand side, air pollution treatment will indirectly stimulate gas consumption increase. Gas power generation will become the dominant. Natural gas as a transportation fuel will bring a good new opportunity. Thus it is believed that as the present natural gas development is restricted by both gas pricing system and infrastructure construction, further reform should be strengthened to break the barriers of systems and mechanisms; and that due to many uncertainties in the natural gas market, the decisive role of market in the resource allocation should be fully exerted to ensure the main force of natural gas in building a dependable energy strategic system in present and future China.

  7. Leaf growth rate per unit thermal time follows QTL-dependent daily patterns in hundreds of maize lines under naturally fluctuating conditions.

    Science.gov (United States)

    Sadok, Walid; Naudin, Philippe; Boussuge, Benoit; Muller, Bertrand; Welcker, Claude; Tardieu, Francois

    2007-02-01

    We have analysed daily patterns of leaf elongation rate (LER) in large data sets with 318 genotypes placed in naturally fluctuating temperature and evaporative demand, and examined the effect of targeted alleles on these patterns. The method consisted, firstly, in expressing elongation rate per unit thermal time, so it became temperature independent; secondly, in a joint analysis of diurnal fluctuations of elongation rate and of micrometeorological conditions in several experiments, and finally, in a comparison of daily patterns between groups of genotypes possessing targeted alleles. (1) Conditions for using thermal time at a time step of 15 min were first tested successfully in 318 recombinant inbred lines (RILs) of three mapping populations. (2) An analysis of 1989 time courses revealed a robust daily pattern of LER per unit thermal time (LERth) over several experiments. LERth was constant during the night and was reproducible (for a given RIL) over up to 10 consecutive nights in different experiments. It declined rapidly during the early morning, closely following the daily pattern of transpiration rate. (3) Groups of RILs carrying alleles conferring a high response to temperature had markedly higher night-time plateau of LER than those with low responses. Groups of RILs with high response to evaporative demand had rapid decreases in elongation rate at the transition between night and day, while this decrease was slower in groups of RILs with low response. These results open the way for using kinetics of responses to environmental stimuli as a phenotyping tool in genetic analyses.

  8. Tackle-related injury rates and nature of injuries in South African Youth Week tournament rugby union players (under-13 to under-18): an observational cohort study

    Science.gov (United States)

    Burger, Nicholas; Lambert, Mike I; Viljoen, Wayne; Brown, James C; Readhead, Clint; Hendricks, Sharief

    2014-01-01

    Objectives The tackle situation is most often associated with the high injury rates in rugby union. Tackle injury epidemiology in rugby union has previously been focused on senior cohorts but less is known about younger cohorts. The aim of this study was to report on the nature and rates of tackle-related injuries in South African youth rugby union players representing their provinces at national tournaments. Design Observational cohort study. Setting Four South African Youth Week tournaments (under-13 Craven Week, under-16 Grant Khomo Week, under-18 Academy Week, under-18 Craven Week). Participants Injury data were collected from 3652 youth rugby union players (population at risk) in 2011 and 2012. Outcome measures Tackle-related injury severity (‘time-loss’ and ‘medical attention’), type and location, injury rate per 1000 h (including 95% CIs). Injury rate ratios (IRR) were calculated and modelled using a Poisson regression. A χ2 analysis was used to detect linear trends between injuries and increasing match quarters. Results The 2012 under-13 Craven Week had a significantly greater ‘time-loss’ injury rate when compared with the 2012 under-18 Academy Week (IRR=4.43; 95% CI 2.13 to 9.21, p<0.05) and under-18 Craven Week (IRR=3.52; 95% CI 1.54 to 8.00, p<0.05). The Poisson regression also revealed a higher probability of ‘overall’ (‘time-loss’ and ‘medical attention’ combined) and ‘time-loss’ tackle-related injuries occurring at the under-13 Craven Week. The proportion of ‘overall’ and ‘time-loss’ injuries increased significantly with each quarter of the match when all four tournaments were combined (p<0.05). Conclusions There was a difference in the tackle-related injury rate between the under-13 tournament and the two under-18 tournaments, and the tackle-related injury rate was higher in the final quarter of matches. Ongoing injury surveillance is required to better interpret these findings. Injury prevention strategies

  9. Comparison of growth rates estimated by otolith reading of Scorpaena porcus and Scorpaena notata caught on artificial and natural reefs of the northern Adriatic sea

    Directory of Open Access Journals (Sweden)

    Giuseppe Scarcella

    2011-01-01

    Full Text Available Despite the high number of studies on fish assemblages associated with artificial reefs and offshore platforms, little information exists on the growth rates of fish living on artificial and natural substrates. Age and growth was determined throughout otolith reading on two commercial scorpionfishes (Scorpaena porcus and Scorpaena notata caught in the surroundings of artificial structures (artificial reefs and gas platforms and natural habitats. Von Bertalanffy growth parameters were calculated for each species separately for each site. Age of S. porcus and S. notata ranged from 0 to 8 years and from 0 to 16 years, respectively. Kimura test applied to Von Bertalanffy growth curves indicated that the individuals of both species inhabiting the artificial structures had higher growth parameters than those caught in the natural habitat. The presence of artificial habitats in the northern Adriatic Sea positively affects growth rates and growth performance of both species, likely for the greater prey availability in respect to the natural open sea.Apesar do elevado número de estudos sobre as assembléias de peixes associadas a recifes artificiais e plataformas offshore, existe pouca informação sobre as taxas de crescimento dos peixes que vivem em substratos artificiais e naturais. A idade e crescimento foram determinados pela leitura de otólitos em dois peixes escorpião comerciais (Scorpaena porcus e Scorpaena notata capturados nas imediações de estruturas artificiais (recifes artificiais e plataformas de gás e habitats naturais. Parâmetros de crescimento de von Bertalanffy foram calculadoss separadamente para cada espécie e cada local. A idade de Scorpaena porcus e Scorpaena notata variou entre 0 e 8 anos e 0 e 16 anos, respectivamente. O teste Kimura aplicado às curvas de crescimento de Bertalanffy indicaram que os indivíduos das duas espécies que habitam as estruturas artificiais tinham parâmetros de crescimento mais elevados do que

  10. Comparison of facility-level methane emission rates from natural gas production well pads in the Marcellus, Denver-Julesburg, and Uintah Basins

    Science.gov (United States)

    Omara, M.; Li, X.; Sullivan, M.; Subramanian, R.; Robinson, A. L.; Presto, A. A.

    2015-12-01

    The boom in shale natural gas (NG) production, brought about by advances in horizontal drilling and hydraulic fracturing, has yielded both economic benefits and concerns about environmental and climate impacts. In particular, leakages of methane from the NG supply chain could substantially increase the carbon footprint of NG, diminishing its potential role as a transition fuel between carbon intensive fossil fuels and renewable energy systems. Recent research has demonstrated significant variability in measured methane emission rates from NG production facilities within a given shale gas basin. This variability often reflect facility-specific differences in NG production capacity, facility age, utilization of emissions capture and control, and/or the level of facility inspection and maintenance. Across NG production basins, these differences in facility-level methane emission rates are likely amplified, especially if significant variability in NG composition and state emissions regulations are present. In this study, we measured methane emission rates from the NG production sector in the Marcellus Shale Basin (Pennsylvania and West Virginia), currently the largest NG production basin in the U.S., and contrast these results with those of the Denver-Julesburg (Colorado) and Uintah (Utah) shale basins. Facility-level methane emission rates were measured at 106 NG production facilities using the dual tracer flux (nitrous oxide and acetylene), Gaussian dispersion simulations, and the OTM 33A techniques. The distribution of facility-level average methane emission rate for each NG basin will be discussed, with emphasis on how variability in NG composition (i.e., ethane-to-methane ratios) and state emissions regulations impact measured methane leak rates. While the focus of this presentation will be on the comparison of methane leak rates among NG basins, the use of three complimentary top-down methane measurement techniques provides a unique opportunity to explore the

  11. Understanding differences in conception and abortion rates among under-20 year olds in Britain and France: Examining the contribution of social disadvantage.

    Science.gov (United States)

    Scott, Rachel H; Bajos, Nathalie; Slaymaker, Emma; Wellings, Kaye; Mercer, Catherine H

    2017-01-01

    Socioeconomic status has been shown to be associated with sexual activity, contraceptive-use, pregnancy and abortion among young people. Less is known about whether the strength of the association differs for each outcome, between men and women, or cross-nationally. We investigate this using contemporaneous national probability survey data from Britain and France. Data were analysed for 17-29 year-olds in Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3, n = 5959) undertaken 2010-2012, and the 2010 French Fertility, Contraception and Sexual Dysfunction survey (FECOND, n = 3027). For each country, we estimated the gender-specific prevalence of sex before-16, contraceptive-use, conception before-20, and abortion in the event of conception, and used logistic regression to examine associations between two measures of socioeconomic status-educational-level and parental socioeconomic-group-and each outcome. We tested for interactions between socioeconomic characteristics and country, and socioeconomic characteristics and gender, for each outcome. For each outcome, Britain and France differed with regard to prevalence but associations with socioeconomic characteristics were similar. Respondents of higher educational level, and, less consistently, with parents from higher socioeconomic-groups, were less likely to report sex before-16 (Britain, men: adjusted OR (aOR) 0.5, women: aOR 0.5; France, men: aOR 0.5, women: aOR 0.5), no contraception at first sex (Britain, men: aOR 0.4, women: aOR 0.6; France, men: aOR 0.4, women: aOR 0.4), pregnancy before-20 (Britain: aOR 0.3; France: aOR 0.1), and in Britain, a birth rather than an abortion in the event of conception (Britain: aOR 3.1). We found no strong evidence of variation in the magnitude of the associations with socioeconomic characteristics by country or gender. Population level differences in conception and abortion rates between the two countries may partly be driven by the larger proportion

  12. Understanding differences in conception and abortion rates among under-20 year olds in Britain and France: Examining the contribution of social disadvantage.

    Directory of Open Access Journals (Sweden)

    Rachel H Scott

    Full Text Available Socioeconomic status has been shown to be associated with sexual activity, contraceptive-use, pregnancy and abortion among young people. Less is known about whether the strength of the association differs for each outcome, between men and women, or cross-nationally. We investigate this using contemporaneous national probability survey data from Britain and France.Data were analysed for 17-29 year-olds in Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3, n = 5959 undertaken 2010-2012, and the 2010 French Fertility, Contraception and Sexual Dysfunction survey (FECOND, n = 3027. For each country, we estimated the gender-specific prevalence of sex before-16, contraceptive-use, conception before-20, and abortion in the event of conception, and used logistic regression to examine associations between two measures of socioeconomic status-educational-level and parental socioeconomic-group-and each outcome. We tested for interactions between socioeconomic characteristics and country, and socioeconomic characteristics and gender, for each outcome.For each outcome, Britain and France differed with regard to prevalence but associations with socioeconomic characteristics were similar. Respondents of higher educational level, and, less consistently, with parents from higher socioeconomic-groups, were less likely to report sex before-16 (Britain, men: adjusted OR (aOR 0.5, women: aOR 0.5; France, men: aOR 0.5, women: aOR 0.5, no contraception at first sex (Britain, men: aOR 0.4, women: aOR 0.6; France, men: aOR 0.4, women: aOR 0.4, pregnancy before-20 (Britain: aOR 0.3; France: aOR 0.1, and in Britain, a birth rather than an abortion in the event of conception (Britain: aOR 3.1. We found no strong evidence of variation in the magnitude of the associations with socioeconomic characteristics by country or gender.Population level differences in conception and abortion rates between the two countries may partly be driven by the larger

  13. The Effect of Teaching Games of Understanding as a Coaching Instruction had on Adjust, Cover and Heart Rate among Malaysian and Indian Junior Hockey Players

    Directory of Open Access Journals (Sweden)

    Sanmuga Nathan

    2017-06-01

    Full Text Available The field hockey coaching process across both Malaysia and India favours a traditional, coach-centred approach of mastering technical skills in terms of game play parameters, fitness, intensity, and load training, whereas a tactical- and player-centred pedagogical approach still takes a backseat. On the other hand, the Teaching Games for Understanding (TGfU model offers tactical-cognitive instruction and is gaining international recognition for its ability to produce intelligent players via a problem-solving approach in game play. Therefore, the purpose of this quasi-experimental study was to investigate the effect of TGfU compared to skill mastery instruction, termed as Skill Drill Technical (SDT, among Malaysian and Indian elite junior hockey players in term of the game play attributes of adjust and cover in 5 vs. 5 small-sided game play and game play intensity via heart rate (HR at different points of game play. A total of n = 60 players with an average age of 15 ± 1.03 was selected via simple random sampling from both countries involved in this study and assigned equally to groups, with 15 per group for TGfU and for SDT across Malaysia and India. Gathered data were analysed using the ANOVA and ANCOVA techniques. Findings indicated that there were no significant differences for adjust in 5 vs. 5 game play between TGfU and SDT across Malaysia and India after the intervention. For cover, there was significant improvement for Malaysian players using the TGfU model compared to SDT. In contrast, there was no significant difference between these two models among the Indian players after the intervention. There was significant difference between these two models in terms of warm-up HR across the two countries, and HR was higher via TGfU. For HR immediately after the 5 vs. 5 game play intervention and HR after three minutes’ recovery, Indian players with TGfU recorded a higher and significant difference compared to SDT. However, findings indicated

  14. The influence of contraception, abortion, and natural family planning on divorce rates as found in the 2006–2010 National Survey of Family Growth

    Science.gov (United States)

    Fehring, Richard J.

    2015-01-01

    The purpose of this study was to determine the influence of contraception, abortion, and natural family planning (NFP) on divorce rates of US women of reproductive age. The variables of importance of religion and frequency of church attendance were also included in the analysis. The study involved 5,530 reproductive age women in the (2006–2010) National Survey of Family Growth who indicate that they were ever married. Among the women who ever used NFP only 9.6 percent were currently divorced compared with the 14.4 percent who were currently divorced among the women who never used NFP (x2 = 5.34, P NFP users the reason might be due to their religiosity. Lay summary: Providers of natural family planning (NFP) frequently mention that couples who practice NFP have fewer divorces compared to couples who use contraception. Evidence for this comment is weak. This study utilized a large data set of 5,530 reproductive age women to determine the influence that contraception, sterilization, abortion, and NFP has on divorce rates. Among the women participants who ever used NFP only 9.6 percent were currently divorced compared with the 14.4 percent who used methods of contraception, sterilization or abortion as a family planning method. Frequency of church attendance also reduced the likelihood of divorce. PMID:26912935

  15. Up-Conversion Intersystem Crossing Rates in Organic Emitters for Thermally Activated Delayed Fluorescence: Impact of the Nature of Singlet vs Triplet Excited States

    KAUST Repository

    Samanta, Pralok Kumar

    2017-02-28

    The rates for up-conversion intersystem crossing (UISC) from the T1 state to the S1 state are calculated for a series of organic emitters with an emphasis on thermally activated delayed fluorescence (TADF) materials. Both the spin-orbit coupling and the energy difference between the S1 and T1 states (ΔEST) are evaluated, at the density functional theory (DFT) and time-dependent DFT levels. The calculated UISC rates and ΔEST values are found to be in good agreement with available experimental data. Our results underline that small ΔEST values and sizable spin-orbit coupling matrix elements have to be simultaneously realized in order to facilitate UISC and ultimately TADF. Importantly, the spatial separation of the highest occupied and lowest unoccupied molecular orbitals of the emitter, a widely accepted strategy for the design of TADF molecules, does not necessarily lead to a sufficient reduction in ΔEST; in fact, either a significant charge-transfer (CT) contribution to the T1 state or a minimal energy difference between the local-excitation and charge-transfer triplet states is required to achieve a small ΔEST. Also, having S1 and T1 states of a different nature is found to strongly enhance spin-orbit coupling, which is consistent with the El-Sayed rule for ISC rates. Overall, our results indicate that having either similar energies for the local-excitation and charge-transfer triplet states or the right balance between a substantial CT contribution to T1 and somewhat different natures of the S1 and T1 states, paves the way toward UISC enhancement and thus TADF efficiency improvement.

  16. Space and panic : The application of space syntax to understand the relationship between mortality rates and spatial configuration in Banda Aceh during the tsunami 2004

    NARCIS (Netherlands)

    Fakhrurrazi, F.; Van Nes, A.

    2012-01-01

    The aim of this paper is to reveal the correlation between mortality rates from the tsunami of 2004 and the spatial structure of Banda Aceh’s street net. Structurally, the city is divided up in several small villages, which consists of a couple of urban blocks. The mortality rates for each of these

  17. Determination of exposure rates from natural background radiation in Khartoum using LiF:Mg,Cu,P (GR-200) and CaSo4: Mn TLD chips

    International Nuclear Information System (INIS)

    Suliman, I.I.; Khangi, F.A.; Shaddad, I.A.; Suliman, I.A.; El Amin, O.I.

    2002-01-01

    The exposure rates from natural background radiation - including terrestrial gamma radiation and the ionizing component of cosmic rays - were measured for the first time in the city of khartoum using two types of TLD materials: LiF:Mg,Cu,P (GR-200) and CaSo 4 :Mn TLD chips. Measurements were performed at two sites simultaneously, one site was selected on land in the vicinity of the Sudan Atomic Energy Commission, for the purposes of the measurement of the total exposure rate outdoors, while the other site was located on a buoy anchored in the Blue Nile, and was selected to measure the exposure rate due to the ionizing component of cosmic rays. The investigations were conducted for periods of between 5 and 28 days. Calibration was performed on a selected number of dosimeters to determine the exposure rates at each site. The exposure rates from the ionizing component of cosmic rays in Khartoum were found to be respectively 33 nGy.h -1 and 30 nGy.h -1 , in the measurements performed within the scope of this work using GR-200 and CaSo 4 :Mn dosimeters, while the total values for exposure on land were found to be 45 nGy.h -1 and 42 nGy.h -1 respectively. These values compare reasonably well with other national averages reported in the UNSCEAR publication. The comparison of the results for the two dosimetric materials demonstrates both the sensitivity and suitability of GR-200 for the purposes of environmental monitoring (orig.)

  18. Did the suicide barrier work after all? Revisiting the Bloor Viaduct natural experiment and its impact on suicide rates in Toronto.

    Science.gov (United States)

    Sinyor, Mark; Schaffer, Ayal; Redelmeier, Donald A; Kiss, Alex; Nishikawa, Yasunori; Cheung, Amy H; Levitt, Anthony J; Pirkis, Jane

    2017-06-19

    This research aims to determine the long-term impact of the Bloor Street Viaduct suicide barrier on rates of suicide in Toronto and whether media reporting had any impact on suicide rates. Natural experiment. City of Toronto, Canada; records at the chief coroner's office of Ontario 1993-2003 (11 years before the barrier) and 2004-2014 (11 years after the barrier). 5403 people who died by suicide in the city of Toronto. Changes in yearly rates of suicide by jumping at Bloor Street Viaduct, other bridges including nearest comparison bridge and walking distance bridges, and buildings, and by other means. Suicide rates at the Bloor Street Viaduct declined from 9.0 deaths/year before the barrier to 0.1 deaths/year after the barrier (incidence rate ratio (IRR) 0.005, 95% CI 0.0005 to 0.19, p=0.002). Suicide deaths from bridges in Toronto also declined significantly (IRR 0.53, 95% CI 0.40 to 0.71, psuicide at the Bloor Street Viaduct were associated with an increase in suicide-by-jumping from bridges the following year. The current study demonstrates that, over the long term, suicide-by-jumping declined in Toronto after the barrier with no associated increase in suicide by other means. That is, the barrier appears to have had its intended impact at preventing suicide despite a short-term rise in deaths at other bridges that was at least partially influenced by a media effect. Research examining barriers at other locations should interpret short-term results with caution. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Global-scale attribution of anthropogenic and natural dust sources and their emission rates based on MODIS Deep Blue aerosol products

    Science.gov (United States)

    Ginoux, Paul; Prospero, Joseph M.; Gill, Thomas E.; Hsu, N. Christina; Zhao, Ming

    2012-09-01

    Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Here we present a global-scale high-resolution (0.1°) mapping of sources based on Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue estimates of dust optical depth in conjunction with other data sets including land use. We ascribe dust sources to natural and anthropogenic (primarily agricultural) origins, calculate their respective contributions to emissions, and extensively compare these products against literature. Natural dust sources globally account for 75% of emissions; anthropogenic sources account for 25%. North Africa accounts for 55% of global dust emissions with only 8% being anthropogenic, mostly from the Sahel. Elsewhere, anthropogenic dust emissions can be much higher (75% in Australia). Hydrologic dust sources (e.g., ephemeral water bodies) account for 31% worldwide; 15% of them are natural while 85% are anthropogenic. Globally, 20% of emissions are from vegetated surfaces, primarily desert shrublands and agricultural lands. Since anthropogenic dust sources are associated with land use and ephemeral water bodies, both in turn linked to the hydrological cycle, their emissions are affected by climate variability. Such changes in dust emissions can impact climate, air quality, and human health. Improved dust emission estimates will require a better mapping of threshold wind velocities, vegetation dynamics, and surface conditions (soil moisture and land use) especially in the sensitive regions identified here, as well as improved ability to address small-scale convective processes producing dust via cold pool (haboob) events frequent in monsoon regimes.

  20. Effects of Jigsaw Cooperative Learning and Animation Techniques on Students' Understanding of Chemical Bonding and Their Conceptions of the Particulate Nature of Matter

    Science.gov (United States)

    Karacop, Ataman; Doymus, Kemal

    2013-01-01

    The aim of this study was to determine the effect of jigsaw cooperative learning and computer animation techniques on academic achievements of first year university students attending classes in which the unit of chemical bonding is taught within the general chemistry course and these students' learning of the particulate nature of matter of this…

  1. What Do Israeli High School Students Understand about Biodiversity? An Evaluation of the High School Biology Programme, "Nature in a World of Change"

    Science.gov (United States)

    Dor-Haim, Shayli; Amir, Ruth; Dodick, Jeff

    2011-01-01

    One of the most serious problems facing our planet is the biodiversity crisis. As a solution to this problem, both scientists and educators have emphasised the need for educating people about how to conserve the Earth's biodiversity. As a small contribution to this effort, we have designed a learning unit about biodiversity, "Nature in a…

  2. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    International Nuclear Information System (INIS)

    Pereira, Wagner de; Kelecom, Alphonse; Py Junior, Delcy de Azevedo

    2007-01-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10 3 μGy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10 0 μGy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  3. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetité, Bahia, Brazil

    Science.gov (United States)

    Pereira, Wagner de S.; Kelecom, Alphonse; Py Júnior, Delcy de Azevedo

    2008-08-01

    The uranium mining at Caetité (Uranium Concentrate Unit—URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5×103 μGy y-1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51×100 μGy y-1, that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota.

  4. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetite, Bahia, Brazil

    International Nuclear Information System (INIS)

    Pereira, Wagner de S; Kelecom, Alphonse; Azevedo Py Junior, Delcy de

    2008-01-01

    The uranium mining at Caetite (Uranium Concentrate Unit--URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5x10 3 μGy y -1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51x10 0 μGy y -1 , that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota

  5. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de [Industrias Nucleares do Brasil S.A. (INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Unidade de Tratamento de Minerios], E-mail: wspereira@inb.gov.br; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-graduacao em Ciencia Ambiental; Py Junior, Delcy de Azevedo [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil). Coordenacao de Protecao Radiologica. Unidade de Concentrado de Uranio], E-mail: Delcy@inb.gov.br

    2007-07-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10{sup 3} {mu}Gy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10{sup 0} {mu}Gy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  6. The Impact of Short-Term Science Teacher Professional Development on the Evaluation of Student Understanding and Errors Related to Natural Selection. CRESST Report 822

    Science.gov (United States)

    Buschang, Rebecca E.

    2012-01-01

    This study evaluated the effects of a short-term professional development session. Forty volunteer high school biology teachers were randomly assigned to one of two professional development conditions: (a) developing deep content knowledge (i.e., control condition) or (b) evaluating student errors and understanding in writing samples (i.e.,…

  7. The Impact of Short-Term Science Teacher Professional Development on the Evaluation of Student Understanding and Errors Related to Natural Selection

    Science.gov (United States)

    Buschang, Rebecca Ellen

    2012-01-01

    This study evaluated the effects of a short-term professional development session. Forty volunteer high school biology teachers were randomly assigned to one of two professional development conditions: (a) developing deep content knowledge (i.e., control condition) or (b) evaluating student errors and understanding in writing samples (i.e.,…

  8. Understanding physics

    CERN Document Server

    Cassidy, David; Rutherford, James

    2002-01-01

    Understanding Physics provides a thorough grounding in contemporary physics while placing physics into its social and historical context Based in large part on the highly respected Project Physics Course developed by two of the authors, it also integrates the results of recent pedagogical research The text thus - teaches about the basic phenomena in the physical world and the concepts developed to explain them - shows that science is a rational human endeavor with a long and continuing tradition, involving many different cultures and people - develops facility in critical thinking, reasoned argumentation, evaluation of evidence, mathematical modeling, and ethical values The treatment emphasizes not only what we know but also how we know it, why we believe it, and what effects that knowledge has - Why do we believe the Earth and planets revolve around the Sun? - Why do we believe that matter is made of atoms? - How do relativity theory and quantum mechanics alter our conception of Nature and in what ways do th...

  9. Understanding shallow landslides in Campos do Jordão municipality – Brazil: disentangling the anthropic effects from natural causes in the disaster of 2000

    Directory of Open Access Journals (Sweden)

    R. M. Mendes

    2018-01-01

    Full Text Available Located in a mountainous area of south-eastern Brazil, the municipality of Campos do Jordão has been hit by several landslides in recent history. Among those events, the landslides of early 2000 were significant in terms of the number of deaths (10, the population affected and the destruction of infrastructure that was caused. The purpose of this study is to assess the relative contribution of natural and human factors to triggering the landslides of the 2000 event. To achieve this goal, a detailed geotechnical survey was conducted in three representative slopes of the area to obtain geotechnical parameters needed for slope stability analysis. Then, a set of numerical experiments with GEO-SLOPE software was designed, including separate natural and anthropic factors. Results showed that natural factors, that is, high-intensity rainfall and geotechnical conditions, were not severe enough to trigger landslides in the study area and that human disturbance was entirely responsible for the landslide events of 2000. Since the anthropic effects used in the simulations are typical of hazardous urban areas in Brazil, we concluded that the implementation of public policies that constrain the occupation of landslide susceptible areas are urgently needed.

  10. Understanding shallow landslides in Campos do Jordão municipality - Brazil: disentangling the anthropic effects from natural causes in the disaster of 2000

    Science.gov (United States)

    Mendes, Rodolfo M.; de Andrade, Márcio Roberto M.; Tomasella, Javier; de Moraes, Márcio Augusto E.; Scofield, Graziela B.

    2018-01-01

    Located in a mountainous area of south-eastern Brazil, the municipality of Campos do Jordão has been hit by several landslides in recent history. Among those events, the landslides of early 2000 were significant in terms of the number of deaths (10), the population affected and the destruction of infrastructure that was caused. The purpose of this study is to assess the relative contribution of natural and human factors to triggering the landslides of the 2000 event. To achieve this goal, a detailed geotechnical survey was conducted in three representative slopes of the area to obtain geotechnical parameters needed for slope stability analysis. Then, a set of numerical experiments with GEO-SLOPE software was designed, including separate natural and anthropic factors. Results showed that natural factors, that is, high-intensity rainfall and geotechnical conditions, were not severe enough to trigger landslides in the study area and that human disturbance was entirely responsible for the landslide events of 2000. Since the anthropic effects used in the simulations are typical of hazardous urban areas in Brazil, we concluded that the implementation of public policies that constrain the occupation of landslide susceptible areas are urgently needed.

  11. Population-Level Differentiation in Growth Rates and Leaf Traits in Seedlings of the Neotropical Live Oak Quercus oleoides Grown under Natural and Manipulated Precipitation Regimes

    Directory of Open Access Journals (Sweden)

    Jose A. Ramírez-Valiente

    2017-05-01

    Full Text Available Widely distributed species are normally subjected to spatial heterogeneity in environmental conditions. In sessile organisms like plants, adaptive evolution and phenotypic plasticity of key functional traits are the main mechanisms through which species can respond to environmental heterogeneity and climate change. While extended research has been carried out in temperate species in this regard, there is still limited knowledge as to how species from seasonally-dry tropical climates respond to spatial and temporal variation in environmental conditions. In fact, studies of intraspecific genetically-based differences in functional traits are still largely unknown and studies in these ecosystems have largely focused on in situ comparisons where environmental and genetic effects cannot be differentiated. In this study, we tested for ecotypic differentiation and phenotypic plasticity in leaf economics spectrum (LES traits, water use efficiency and growth rates under natural and manipulated precipitation regimes in a common garden experiment where seedlings of eight populations of the neotropical live oak Quercus oleoides were established. We also examined the extent to which intraspecific trait variation was associated with plant performance under different water availability. Similar to interspecific patterns among seasonally-dry tropical tree species, live oak populations with long and severe dry seasons had higher leaf nitrogen content and growth rates than mesic populations, which is consistent with a “fast” resource-acquisition strategy aimed to maximize carbon uptake during the wet season. Specific leaf area (SLA was the best predictor of plant performance, but contrary to expectations, it was negatively associated with relative and absolute growth rates. This observation was partially explained by the negative association between SLA and area-based photosynthetic rates, which is contrary to LES expectations but similar to other recent

  12. Understanding the relationship between the Centers for Medicare and Medicaid Services' Hospital Compare star rating, surgical case volume, and short-term outcomes after major cancer surgery.

    Science.gov (United States)

    Kaye, Deborah R; Norton, Edward C; Ellimoottil, Chad; Ye, Zaojun; Dupree, James M; Herrel, Lindsey A; Miller, David C

    2017-11-01

    Both the Centers for Medicare and Medicaid Services' (CMS) Hospital Compare star rating and surgical case volume have been publicized as metrics that can help patients to identify high-quality hospitals for complex care such as cancer surgery. The current study evaluates the relationship between the CMS' star rating, surgical volume, and short-term outcomes after major cancer surgery. National Medicare data were used to evaluate the relationship between hospital star ratings and cancer surgery volume quintiles. Then, multilevel logistic regression models were fit to examine the association between cancer surgery outcomes and both star rankings and surgical volumes. Lastly, a graphical approach was used to compare how well star ratings and surgical volume predicted cancer surgery outcomes. This study identified 365,752 patients undergoing major cancer surgery for 1 of 9 cancer types at 2,550 hospitals. Star rating was not associated with surgical volume (P cancer surgery outcomes (mortality, complication rate, readmissions, and prolonged length of stay). The adjusted predicted probabilities for 5- and 1-star hospitals were 2.3% and 4.5% for mortality, 39% and 48% for complications, 10% and 15% for readmissions, and 8% and 16% for a prolonged length of stay, respectively. The adjusted predicted probabilities for hospitals with the highest and lowest quintile cancer surgery volumes were 2.7% and 5.8% for mortality, 41% and 55% for complications, 12.2% and 11.6% for readmissions, and 9.4% and 13% for a prolonged length of stay, respectively. Furthermore, surgical volume and the star rating were similarly associated with mortality and complications, whereas the star rating was more highly associated with readmissions and prolonged length of stay. In the absence of other information, these findings suggest that the star rating may be useful to patients when they are selecting a hospital for major cancer surgery. However, more research is needed before these ratings can

  13. 3D structure of macropore networks within natural and de-embarked estuary saltmarsh sediments: towards an improved understanding of network structural control over hydrologic function

    Science.gov (United States)

    Carr, Simon; Spencer, Kate; James, Tempest; Lucy, Diggens

    2015-04-01

    Saltmarshes are globally important environments which, though occupying pollution resulting in degradation. To compensate for this habitat loss many coastal restoration projects have been implemented over the last few decades, largely driven by legislative requirements for improved biodiversity e.g. the EU Habitats Directive and Birds Directive. However, there is growing evidence that restored saltmarshes, recreated through the return to tidal inundation of previously drained and defended low-lying coastal land, do not have the same species composition even after 100 years and while environmental enhancement has been achieved, there may be consequences for ecosystem functioning This study presents the findings of a comparative analysis of detailed sediment structure and hydrological functioning of equivalent natural and de-embanked saltmarsh sediments at Orplands Farm, Essex, UK. 3D x-ray CT scanning of triplicate undisturbed sediment cores recovered in 2013 have been used to derive detailed volumetric reconstructions of macropore structure and networks, and to infer differences in bulk microporosity between natural and de-embanked saltmarshes. These volumes have been further visualised for qualitative analysis of the main sediment components, and extraction of key macropore space parameters for quantified analysis including total porosity and connectivity, as well as structure, organisation and efficiency (tortuosity) of macropore networks. Although total porosity was significantly greater within the de-embanked saltmarsh sediments, pore networks in these samples were less organised and more tortuous, and were also inferred to have significantly lower micro-porosity than those of the natural saltmarsh. These datasets are applied to explain significant differences in the hydraulic behaviour and functioning observed between natural and de-embarked saltmarsh at Orplands. Piezometer wells and pressure transducers recorded fluctuations in water level at 15 minute

  14. The influence of contraception, abortion, and natural family planning on divorce rates as found in the 2006-2010 National Survey of Family Growth.

    Science.gov (United States)

    Fehring, Richard J

    2015-08-01

    The purpose of this study was to determine the influence of contraception, abortion, and natural family planning (NFP) on divorce rates of US women of reproductive age. The variables of importance of religion and frequency of church attendance were also included in the analysis. The study involved 5,530 reproductive age women in the (2006-2010) National Survey of Family Growth who indicate that they were ever married. Among the women who ever used NFP only 9.6 percent were currently divorced compared with the 14.4 percent who were currently divorced among the women who never used NFP (x (2) = 5.34, P sterilization, and/or methods of contraception increased the likelihood of divorce - up to two times. Frequency of church attendance decreased the risk of divorce. Although there is less divorce among NFP users the reason might be due to their religiosity. Lay summary: Providers of natural family planning (NFP) frequently mention that couples who practice NFP have fewer divorces compared to couples who use contraception. Evidence for this comment is weak. This study utilized a large data set of 5,530 reproductive age women to determine the influence that contraception, sterilization, abortion, and NFP has on divorce rates. Among the women participants who ever used NFP only 9.6 percent were currently divorced compared with the 14.4 percent who used methods of contraception, sterilization or abortion as a family planning method. Frequency of church attendance also reduced the likelihood of divorce.

  15. Naturally Occurring Canine Invasive Urinary Bladder Cancer: A Complementary Animal Model to Improve the Success Rate in Human Clinical Trials of New Cancer Drugs

    Directory of Open Access Journals (Sweden)

    Christopher M. Fulkerson

    2017-01-01

    Full Text Available Genomic analyses are defining numerous new targets for cancer therapy. Therapies aimed at specific genetic and epigenetic targets in cancer cells as well as expanded development of immunotherapies are placing increased demands on animal models. Traditional experimental models do not possess the collective features (cancer heterogeneity, molecular complexity, invasion, metastasis, and immune cell response critical to predict success or failure of emerging therapies in humans. There is growing evidence, however, that dogs with specific forms of naturally occurring cancer can serve as highly relevant animal models to complement traditional models. Invasive urinary bladder cancer (invasive urothelial carcinoma (InvUC in dogs, for example, closely mimics the cancer in humans in pathology, molecular features, biological behavior including sites and frequency of distant metastasis, and response to chemotherapy. Genomic analyses are defining further intriguing similarities between InvUC in dogs and that in humans. Multiple canine clinical trials have been completed, and others are in progress with the aim of translating important findings into humans to increase the success rate of human trials, as well as helping pet dogs. Examples of successful targeted therapy studies and the challenges to be met to fully utilize naturally occurring dog models of cancer will be reviewed.

  16. Growth rate, health and welfare in a dairy herd with natural suckling until 6–8 weeks of age: a case report

    Directory of Open Access Journals (Sweden)

    Mejdell Cecilie

    2007-06-01

    Full Text Available Abstract Over a period of two years, growth rate and health were measured for dairy calves allowed to suckle their mothers up to 6–8 weeks of age. Thirty-one calves were weighted weekly, and the mean daily growth rate was 1.2 ± 0.03 kg from birth up to 13 weeks of age. Illness in calves and young stock was not observed. In the cows, the mean incidences of ketosis, displaced abomasum, puerperal paresis, mastitis, teat injury and retained placenta were 0, 0, 8, 22, 1 and 1%, respectively, during a 6-year period. The mean daily gain of 56 growing bulls was 1.4 kg when slaughtered at 15 months of age, which is higher than the mean daily gain of 0.95 kg in the population. Probiotics, hormones and vaccines were not used, and antibiotics were only used for treating illness. The present study indicates many advantages and few problems when dairy calves are penned together with the cows and allowed natural feeding up to 6–8 weeks of age. This production system was easy to manage, preferred by the farmer, and may satisfy the public concern regarding the practice of immediate separation of cow and calf in commercial milk production.

  17. HCG administration after endogenous LH rise negatively influences pregnancy rate in modified natural cycle for frozen-thawed euploid blastocyst transfer: a pilot study.

    Science.gov (United States)

    Litwicka, Katarzyna; Mencacci, Cecilia; Arrivi, Cristiana; Varricchio, Maria Teresa; Caragia, Alina; Minasi, Maria Giulia; Greco, Ermanno

    2017-11-17

    The aim of the present study was to evaluate whether in a modified natural cycle (modified-NC) for a frozen-thawed single euploid blastocyst transfer, a critical LH value, above which human chorionic gonadotropin (hCG) administration should be avoided, may be defined. One hundred and sixty-seven patients underwent modified natural cycle in order to transfer a single frozen-thawed euploid blastocyst. All embryos were obtained by intracytoplasmic sperm injection and were biopsied at the blastocyst stage and analyzed by means of array comparative genomic hybridization (aCGH). Ovulation was induced using 10.000 IU hCG when the mean follicle diameter was at least of 17 mm, independently from LH values. The primary end points were the hCG-positive test and clinical pregnancy. The interim analysis showed that LH value ≥ 13 mIU/ml on the day of hCG injection may negatively influence the clinical results, suggesting that in this condition, it should be advisable waiting for spontaneous ovulation. Among patients who received hCG for ovulation induction, the hCG-positive test and clinical pregnancy rates in modified-NC were significantly lower in cycles with LH ≥ 13 mIU/ml in respect to those with LH hCG administration led to significantly lower rates of hCG-positive test (45.4 vs 74.5% in hCG administration and spontaneous ovulation groups, respectively) and clinical pregnancy (36.4 vs 64.7% in hCG administration and spontaneous ovulation groups, respectively). The baseline patient characteristics were comparable in all groups. The findings of this study highlight that LH elevation ≥ 13 mIU/ml prior to hCG administration may negatively affect clinical pregnancy rates in modified-NC for single euploid blastocyst transfer. The LH determination should be routinely performed during follicular monitoring. In the presence of LH level ≥ 13 mIU/ml, hCG administration should be avoided, and the embryo transfer should be planned only after spontaneous

  18. The BioSCWG Project: Understanding the Trade-Offs in the Process and Thermal Design of Hydrogen and Synthetic Natural Gas Production

    Directory of Open Access Journals (Sweden)

    Mohamed Magdeldin

    2016-10-01

    Full Text Available This article presents a summary of the main findings from a collaborative research project between Aalto University in Finland and partner universities. A comparative process synthesis, modelling and thermal assessment was conducted for the production of Bio-synthetic natural gas (SNG and hydrogen from supercritical water refining of a lipid extracted algae feedstock integrated with onsite heat and power generation. The developed reactor models for product gas composition, yield and thermal demand were validated and showed conformity with reported experimental results, and the balance of plant units were designed based on established technologies or state-of-the-art pilot operations. The poly-generative cases illustrated the thermo-chemical constraints and design trade-offs presented by key process parameters such as plant organic throughput, supercritical water refining temperature, nature of desirable coproducts, downstream indirect production and heat recovery scenarios. The evaluated cases favoring hydrogen production at 5 wt. % solid content and 600 °C conversion temperature allowed higher gross syngas and CHP production. However, mainly due to the higher utility demands the net syngas production remained lower compared to the cases favoring BioSNG production. The latter case, at 450 °C reactor temperature, 18 wt. % solid content and presence of downstream indirect production recorded 66.5%, 66.2% and 57.2% energetic, fuel-equivalent and exergetic efficiencies respectively.

  19. Understanding human movement through spatial technologies. The role of natural areas of transit in the Late Prehistory of South-western Iberia

    Directory of Open Access Journals (Sweden)

    Murrieta-Flores, Patricia

    2012-06-01

    Full Text Available Archaeological, historical, and ethnographic research has demonstrated how mountainous environments influence the socio-cultural dynamics of the communities that live in them and in their neighbouring areas. The development of these communities tends to occur at the margins, often far away from centres of political power. This marginality is also extended to movement in these regions, where mountain ranges regularly constitute mighty obstacles on account of their natural configuration which plays a central role in strategy, commerce and travelling. In the case of western Sierra Morena in Spain, its constitution shaped both the ways of transit through the mountains during Later Prehistory and the historical routes of communication that traverse Andalucía. Using a GIS methodology developed specifically to identify particular characteristics of the landscape relevant to human movement, such as passageways, crossing points, and natural areas of transit, we examine the role that natural accessibility had for the late prehistoric societies of this region. We conclude that the location of their habitats and symbolic places are strongly related to corridors, possibly due to an increasing importance of herding activities.

    Investigaciones arqueológicas, históricas y etnográficas han demostrado como los ambientes de montaña tienen una profunda influencia en las dinámicas socioculturales de las comunidades que viven en ellos y en sus áreas vecinas. El desarrollo de estas sociedades tiende a producirse en los márgenes, usualmente lejos de los centros de poder político. Esta marginación se extiende también a la circulación en estas regiones, donde las cordilleras suelen constituir poderosos obstáculos debido a su configuración natural que juega un papel central en sus estrategias, comercio y movimiento humano. Durante la Prehistoria Reciente, la constitución de Sierra Morena Occidental (España moldeó tanto las vías de tránsito a trav

  20. Recovery of white sturgeon populations through natural production: Understanding the influence of abiotic and biotic factors on spawning and subsequent recruitment

    Science.gov (United States)

    Parsley, M.J.; Anders, P.J.; Miller, Allen I.; Beckman, L.G.; McCabe, G.T.

    2002-01-01

    Recovery or maintenance of sturgeon populations through natural production in perturbed rivers requires adequate knowledge of the abiotic and biotic factors that influence spawning and cause mortality of embryonic, larval, and juvenile life stages. Although it is known that year-class strength of white sturgeon Acipenser transmontanus is determined within 2-3 months after spawning, little is known about specific causes of mortality to early life stages during this period. Initial spawning success is critical in the development of a strong year-class, and maximized recruitment may be dependent upon water temperature and the availability of optimal in-river habitat. Analyses have shown that increased river discharge combined with suitable water temperatures during spawning, egg incubation, yolk sac larvae dispersal, and first exogenous feeding result in greater recruitment. However, little is known about the importance of other variables, such as food availability or losses due to predation that influence year-class strength. ?? 2002 by the American Fisheries Society.

  1. Asphalt Volcanism as a Model to Understand the Geochemical Nature of Pitch Lake, a Planetary Analog for Titan and the Implications towards Methane Flux into Earth's Atmosphere.

    Science.gov (United States)

    Khan, A.

    2016-12-01

    Pitch Lake is located in the southwest peninsula of the island near La Brea in Trinidad and Tobago, covering an area of approximately 46 hectares. It was discovered in the year 1595 and is the largest of three natural asphalt lakes that exist on Earth. Pitch Lake is a large oval shaped reservoir composed of dominantly hydrocarbon compounds, but also includes minor amounts of clay and muddy water. It is a natural liquid asphalt desert, which is nourished by a form of petroleum consisting of mostly asphaltines from the surrounding oil-rich region. The hydrocarbons mix with mud and gases under high pressure during upward seepage, and the lighter portion evaporates or is volatilized, which produces a high-viscosity liquid asphalt residue. The residue on and near the surface is a hydrocarbon matrix, which poses extremely challenging environmental conditions to microorganisms characterized by an average low water activity in the range of 0.49 to 0.75, recalcitrant carbon substrates, and toxic chemical compounds. Nevertheless, an active microbial community of archaea and bacteria, many of them novel strains, was found to inhabit the liquid hydrocarbon matrix of Pitch Lake. Geochemical analyses of minerals, done by our team, which revealed sulfates, sulfides, silicates, and metals, normally associated with deep-water hydrothermal vents leads to our new hypothetical model to describe the origins of Pitch Lake and its importance to atmospheric and earth sciences. Pitch Lake is likely the terrestrial equivalent of an offshore submarine asphalt volcano just as La Brea Tar Pits are in some ways an on-land version of the asphalt volcanoes discovered off shore of Santa Barbara by Valentine et al. in 2010. Asphalt volcanism possibly also creates the habitat for chemosynthetic life that is widespread in this lake, as reported by Schulze-Makuch et al. in 2011 and Meckenstock et al. in 2014.

  2. Advancing the citizen scientist's contributions to documenting and understanding natural hazards: a proof of concept for linking crowdsourced and remotely sensed data on landslide hazards in El Salvador

    Science.gov (United States)

    Anderson, E. R.; Griffin, R.; Markert, K. N.

    2017-12-01

    Scientists, practitioners, policymakers, and citizen groups, share a role in ensuring "that all sectors have access to, understand and can use scientific information for better informed decision-making" (Sendai Framework 2015-2030). When it comes to understanding hazards and exposure, inventories on disaster events are often limited. Thus, there are many opportunities for citizen scientists to engage in improving the collective understanding—and ultimately reduction—of disaster risk. Landslides are very difficult to forecast on spatial and temporal scales meaningful for early warning and evacuation. Heuristic hazard mapping methods are very common in regional hazard zonation and rely on expert knowledge of previous events and local conditions, but they often lack a temporal component. As new data analysis packages are becoming more open and accessible, probabilistic approaches that consider high resolution spatial and temporal dimensions are becoming more common, but this is only possible when rich inventories of landslide events exist. The work presented offers a proof of concept on incorporating crowd-sourced data to improve landslide hazard model performance. Starting with a national inventory of 90 catalogued landslides in El Salvador for a study period of 1998 to 2011, we simulate the addition of over 600 additional crowd-sourced landslide events that would have been identified through human interpretation of high resolution imagery in the Google Earth time slider feature. There is a noticeable improvement in performance statistics between static heuristic hazard models and probabilistic models that incorporate the events identified by the "crowd." Such a dynamic incorporation of crowd-sourced data on hazard events is not so far-fetched. Given the engagement of "local observers" in El Salvador who augment in situ hydro-meteorological measurements, the growing access to Earth observation data to the lay person, and immense interest behind connecting citizen

  3. Understanding the Patterns and Causes of Variability in Distribution, Habitat Use, Abundance, Survival and Reproductive Rates of Three Species of Cetacean in the Alboran Sea, Western Mediterranean

    Science.gov (United States)

    2014-09-30

    covers 18 years. Data on human activities (e.g. fisheries, maritime traffic) are also needed to explore how they interact with the environmental...the presence of an immigrant group that interacted during 3 years with the local bottlenose dolphins of Almería. 5.1.3 Reproductive rates The...in relation to variation in the physical and biological environment and human activities, based on 18 years of data. The study species, bottlenose

  4. Tenax TA extraction to understand the rate-limiting factors in methyl-β-cyclodextrin-enhanced bioremediation of PAH-contaminated soil.

    Science.gov (United States)

    Sun, Mingming; Luo, Yongming; Teng, Ying; Christie, Peter; Jia, Zhongjun; Li, Zhengao

    2013-06-01

    The effectiveness of many bioremediation systems for PAH-contaminated soil may be constrained by low contaminant bioaccessibility due to limited aqueous solubility or large sorption capacity. Information on the extent to which PAHs can be readily biodegraded is of vital importance in the decision whether or not to remediate a contaminated soil. In the present study the rate-limiting factors in methyl-β-cyclodextrin (MCD)-enhanced bioremediation of PAH-contaminated soil were evaluated. MCD amendment at 10 % (w/w) combined with inoculation with the PAH-degrading bacterium Paracoccus sp. strain HPD-2 produced maximum removal of total PAHs of up to 35 %. The desorption of PAHs from contaminated soil was determined before and after 32 weeks of bioremediation. 10 % (w/w) MCD amendment (M2) increased the Tenax extraction of total PAHs from 12 to 30 % and promoted degradation by up to 26 % compared to 6 % in the control. However, the percentage of Tenax extraction for total PAHs was much larger than that of degradation. Thus, in the control and M2 treatment it is likely that during the initial phase the bioaccessibility of PAHs is high and biodegradation rates may be limited by microbial processes. On the other hand, when the soil was inoculated with the PAH-degrading bacterium (CKB and MB2), the slowly and very slowly desorbing fractions (F sl and F vl ) became larger and the rate constants of slow and very slow desorption (k sl and k vl ) became extremely small after bioremediation, suggesting that desorption is likely rate limiting during the second, slow phase of biotransformation. These results have practical implications for site risk assessment and cleanup strategies.

  5. A method to quantify quinone reaction rates with wine relevant nucleophiles: a key to the understanding of oxidative loss of varietal thiols.

    Science.gov (United States)

    Nikolantonaki, Maria; Waterhouse, Andrew L

    2012-08-29

    Quinones are key reactive electrophilic oxidation intermediates in wine. To address this question, the model 4-methyl-1,2-benzoquinone was prepared to study how it reacts with wine nucleophiles. Those investigated included the varietal volatile thiols 4-methyl-4-sulfanylpentan-2-one (4MSP), 3-sulfanylhexan-1-ol (3SH), and 2-furanmethanethiol (2FMT); hydrogen sulfide (H2S); glutathione (GSH); sulfur dioxide; ascorbic acid (AA); and the amino acids methionine (Met) and phenylalanine (Phe) in the first kinetic study of these reactions. Products were observed in fair to quantitative yields, but yields were negligible for the amino acids. The reaction rates of 4-methyl-1,2-benzoquinone toward the nucleophiles were quantified by UV-vis spectrometry monitoring the loss of the quinone chromophore. The observed reaction rates spanned three orders of magnitude, from the unreactive amino acids (Met and Phe) (KNu = 0.0002 s(-1)) to the most reactive nucleophile, hydrogen sulfide (KH2S = 0.4188 s(-1)). Analysis of the kinetic data showed three categories. The first group consisted of the amino acids (Met and Phe) having rates of essentially zero. Next, phloroglucinol has a low rate (KPhl = 0.0064 s(-1)). The next group of compounds includes the volatile thiols having increasing reactions rates K as steric inhibition declined (K4MSP = 0.0060 s(-1), K3SH = 0.0578 s(-1), and K2FMT = 0.0837 s(-1)). These volatile thiols (4MSP, 3SH, 2FMT), important for varietal aromas, showed lower K values than those of the third group, the wine antioxidant compounds (SO2, GSH, AA) and H2S (KNu = 0.3343-0.4188 s(-1)). The characterization of the reaction products between the nucleophiles and 4-methyl-1,2-benzoquinone was performed by using HPLC with high-resolution MS analysis. This study presents the first evidence that the antioxidant compounds, H2S, and wine flavanols could react preferentially with oxidation-induced quinones under specific conditions, providing insight into a mechanism for

  6. Effect of GnRH analogue administration on Day 7 after natural mating on formation accessory corpus luteum, progesterone concentration and conception rate in llamas (Lama glama).

    Science.gov (United States)

    Abalos, Marcos C; Acuña, Francisco; Cancino, Andrea K; Aller, Juan F

    2018-03-01

    The objectives of the present study were to determine the effects of exogenous GnRH administered 7 days after breeding on the formation of an accessory corpus luteum (ACL), plasma progesterone (P 4 ) concentrations and pregnancy rates. Adult females (n = 71) having a follicle ≥ 7 mm in diameter in the ovary were naturally mated (Day 0). On Day 7, ultrasonic examination was performed to confirm the occurrence of ovulation as evidenced by presence of an induced corpus luteum (ICL). Females with an ICL plus a dominant follicle ≥ 7 mm (n = 56) were treated with saline solution (SS, n = 29) or GnRH analogue (n = 27). On Day 14, the formation of an ACL was observed by ultrasonography. Blood samples were collected on Days 7 and 14 to quantify plasma P 4 concentrations. On Day 14, 21 of 27 (77.8%) females in the GnRH group developed an ACL, whereas females in the SS group did not. Progesterone concentrations on Day 7 and 14 in those llamas diagnosed as pregnant on Day 30 were not different (P > 0.05) between groups. In addition, P 4 concentration was similar for GnRH-treated females having two CL to those with a single CL. Pregnancy rates were similar (P > 0.05) between SS and GnRH groups (55.2% compared with 74.1% respectively) and the pregnancy rate for the GnRH group was not affected (P > 0.05) by the number of CL observed at Day 14 (66.6% and 75.6% for females with one and two CL respectively). In conclusion, GnRH administration on Day 7 after breeding leads to ACL formation; however, neither the plasma P 4 concentration nor pregnancy rate was affected by having an ACL. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Using Paired In Situ High Frequency Nitrate Measurements to Better Understand Controls on Nitrate Concentrations and Estimate Nitrification Rates in a Wastewater-Impacted River

    Science.gov (United States)

    Kraus, T. E. C.; O'Donnell, K.; Downing, B. D.; Burau, J. R.; Bergamaschi, B. A.

    2017-10-01

    We used paired continuous nitrate (NO3-) measurements along a tidally affected river receiving wastewater discharge rich in ammonium (NH4+) to quantify rates of change in NO3- concentration (RΔNO3) and estimate nitrification rates. NO3- sensors were deployed 30 km apart in the Sacramento River, California (USA), with the upstream station located immediately above the regional wastewater treatment plant (WWTP). We used a travel time model to track water transit between the stations and estimated RΔNO3 every 15 min (October 2013 to September 2014). Changes in NO3- concentration were strongly related to water temperature. In the presence of wastewater, RΔNO3 was generally positive, ranging from about 7 µM d-1 in the summer to near zero in the winter. Numerous periods when the WWTP halted discharge allowed the RΔNO3 to be estimated under no-effluent conditions and revealed that in the absence of effluent, net gains in NO3- were substantially lower but still positive in the summer and negative (net sink) in the winter. Nitrification rates of effluent-derived NH4 (RNitrific_E) were estimated from the difference between RΔNO3 measured in the presence versus absence of effluent and ranged from 1.5 to 3.4 µM d-1, which is within literature values but tenfold greater than recently reported for this region. RNitrific_E was generally lower in winter (˜2 µM d-1) than summer (˜3 µM d-1). This in situ, high frequency approach provides advantages over traditional discrete sampling, incubation, and tracer methods and allows measurements to be made over broad areas for extended periods of time. Incorporating this approach into environmental monitoring programs can facilitate our ability to protect and manage aquatic systems.

  8. Using paired in situ high frequency nitrate measurements to better understand controls on nitrate concentrations and estimate nitrification rates in a wastewater-impacted river

    Science.gov (United States)

    Kraus, Tamara; O'Donnell, Katy; Downing, Bryan D.; Burau, Jon R.; Bergamaschi, Brian

    2017-01-01

    We used paired continuous nitrate ( ) measurements along a tidally affected river receiving wastewater discharge rich in ammonium ( ) to quantify rates of change in  concentration ( ) and estimate nitrification rates.  sensors were deployed 30 km apart in the Sacramento River, California (USA), with the upstream station located immediately above the regional wastewater treatment plant (WWTP). We used a travel time model to track water transit between the stations and estimated  every 15 min (October 2013 to September 2014). Changes in concentration were strongly related to water temperature. In the presence of wastewater, was generally positive, ranging from about 7 µM d−1 in the summer to near zero in the winter. Numerous periods when the WWTP halted discharge allowed the  to be estimated under no-effluent conditions and revealed that in the absence of effluent, net gains in  were substantially lower but still positive in the summer and negative (net sink) in the winter. Nitrification rates of effluent-derived NH4 ( ) were estimated from the difference between  measured in the presence versus absence of effluent and ranged from 1.5 to 3.4 µM d−1, which is within literature values but tenfold greater than recently reported for this region.  was generally lower in winter (∼2 µM d−1) than summer (∼3 µM d−1). This in situ, high frequency approach provides advantages over traditional discrete sampling, incubation, and tracer methods and allows measurements to be made over broad areas for extended periods of time. Incorporating this approach into environmental monitoring programs can facilitate our ability to protect and manage aquatic systems.

  9. Understanding the nano- and macromechanical behaviour, the failure and fatigue mechanisms of advanced and natural polymer fibres by Raman/IR microspectrometry

    Science.gov (United States)

    Colomban, Philippe

    2013-03-01

    The coupled mechanical and Raman/infrared (IR) analysis of the (nano)structure and texture of synthetic and natural polymer fibres (polyamides (PA66), polyethylene terephthalate (PET), polypropylene (PP), poly(paraphenylene benzobisoxazole) (PBO), keratin/hair, Bombyx mori, Gonometa rufobrunea/postica Antheraea/Tussah silkworms and Nephila Madagascarensis spider silks) is applied so as to differentiate between crystalline and amorphous macromolecules. Bonding is very similar in the two cases but a broader distribution of conformations is observed for the amorphous macromolecules. These conclusions are then used to discuss the modifications induced by the application of a tensile or compressive stress, including the effects of fatigue. Detailed attention is paid to water and the inter-chain coupling for which the importance of hydrogen bonding is reconsidered. The significant role of the ‘amorphous’ bonds/domains in the process of fracture/fatigue is shown. Invited talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN2012, 30 October-2 November 2012, Ha Long, Vietnam.

  10. Application of 210Pb-derived sedimentation rates and dinoflagellate cyst analyses in understanding Pyrodinium bahamense harmful algal blooms in Manila Bay and Malampaya Sound, Philippines.

    Science.gov (United States)

    Sombrito, E Z; Bulos, A dM; Sta Maria, E J; Honrado, M C V; Azanza, Rhodora V; Furio, Elsa F

    2004-01-01

    The number of areas affected by toxic harmful algal bloom (HAB) in the Philippines has been increasing since its first recorded occurrence in 1983. Thus far, HAB has been reported in about 20 areas in the Philippines including major fishery production areas. The HAB-causing organism (Pyrodinium bahamense var. compressum) produces a cyst during its life cycle. Pyrodinium cysts which are deposited in the sediment column may play a role in initiating a toxic bloom. 210Pb-derived sedimentation rate studies in the two important fishing grounds of Manila Bay and Malampaya Sound, Palawan have shown that Pyrodinium cysts may have been present in the sediment even before the first recorded toxic algal bloom in these areas. High sedimentation rates (approximately 1 cm/year) have been observed in the northern and western parts of Manila Bay. The results indicate that the sedimentation processes occurring in these bays would require subsurface cyst concentration analysis in evaluating the potential of an area to act as seed bed.

  11. Application of 210Pb-derived sedimentation rates and dinoflagellate cyst analyses in understanding Pyrodinium bahamense harmful algal blooms in Manila Bay and Malampaya Sound, Philippines

    International Nuclear Information System (INIS)

    Sombrito, E.Z.; Bulos, A.M.; Sta Maria, E.J.; Honrado, M.C.V.; Azanza, Rhodora V.; Furio, Elsa F.

    2004-01-01

    The number of areas affected by toxic harmful algal bloom (HAB) in the Philippines has been increasing since its first recorded occurrence in 1983. Thus far, HAB has been reported in about 20 areas in the Philippines including major fishery production areas. The HAB-causing organism (Pyrodinium bahamense var. compressum) produces a cyst during its life cycle. Pyrodinium cysts which are deposited in the sediment column may play a role in initiating a toxic bloom. 210 Pb-derived sedimentation rate studies in the two important fishing grounds of Manila Bay and Malampaya Sound, Palawan have shown that Pyrodinium cysts may have been present in the sediment even before the first recorded toxic algal bloom in these areas. High sedimentation rates (approximately 1 cm/year) have been observed in the Northern and Western parts of Manila Bay. The results indicate that the sedimentation processes occurring in these bays would require subsurface cyst concentration analysis in evaluating the potential of an area to act as sea bed

  12. Application of {sup 210}Pb-derived sedimentation rates and dinoflagellate cyst analyses in understanding Pyrodinium bahamense harmful algal blooms in Manila Bay and Malampaya Sound, Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Sombrito, E.Z. E-mail: ezsombrito@pnri.dost.gov.ph; Bulos, A.M.; Sta Maria, E.J.; Honrado, M.C.V.; Azanza, Rhodora V.; Furio, Elsa F

    2004-07-01

    The number of areas affected by toxic harmful algal bloom (HAB) in the Philippines has been increasing since its first recorded occurrence in 1983. Thus far, HAB has been reported in about 20 areas in the Philippines including major fishery production areas. The HAB-causing organism (Pyrodinium bahamense var. compressum) produces a cyst during its life cycle. Pyrodinium cysts which are deposited in the sediment column may play a role in initiating a toxic bloom. {sup 210}Pb-derived sedimentation rate studies in the two important fishing grounds of Manila Bay and Malampaya Sound, Palawan have shown that Pyrodinium cysts may have been present in the sediment even before the first recorded toxic algal bloom in these areas. High sedimentation rates (approximately 1 cm/year) have been observed in the Northern and Western parts of Manila Bay. The results indicate that the sedimentation processes occurring in these bays would require subsurface cyst concentration analysis in evaluating the potential of an area to act as sea bed.

  13. Why Do Women Have More Children Than They Want? Understanding Differences in Women’s Ideal and Actual Family Size in a Natural Fertility Population

    Science.gov (United States)

    McAllister, Lisa; Gurven, Michael; Kaplan, Hillard; Stieglitz, Jonathan

    2013-01-01

    Objectives We develop and test a conceptual model of factors influencing women’s ideal family size (IFS) in a natural fertility population, the Tsimane of Bolivia. The model posits affects of socioecology, reproductive history, maternal condition, and men’s IFS. We test three hypotheses for why women may exceed their IFS despite experiencing socioeconomic development: (H1) limited autonomy; (H2) improved maternal condition; and (H3) low returns on investments in embodied capital. Methods Women’s reproductive histories and prospective fertility data were collected from 2002 to 2008 (n = 305 women). Semistructured interviews were conducted with Tsimane women to study the perceived value of parental investment (n = 76). Multiple regression, t-tests, and analysis of variance (ANOVA) are used to test model predictions. Results Women’s IFS is predicted by their socioecology, reproductive history, maternal condition, and husband’s IFS. Hypotheses 2 and 3 are supported. Couples residing near town have smaller IFS (women = 3.75 ± 1.64; men = 3.87 ± 2.64) and less variance in IFS. However, the degree fertility exceeds IFS is inversely correlated with distance to town (Partial r = −0.189, df = 156, P = 0.018). Women living near town have greater maternal condition but 64% value traditional skills over formal schooling and 88% believe living in town is unfeasible. Conclusions While reduced IFS is evident with socioeconomic development, fertility decline may not immediately follow. When perceived benefits of investment in novel forms of embodied capital are low, and somatic wealth and large kin networks persist as important components of fitness, fertility may remain high and increase if maternal condition improves. PMID:22987773

  14. Ethnobotany and natural products: the search for new molecules, new treatments of old diseases or a better understanding of indigenous cultures?

    Science.gov (United States)

    Heinrich, Michael

    2003-01-01

    Results of various projects on Mexican Indian ethnobotany and some of the subsequent pharmacological and phytochemical studies are summarised focusing both on chemical-pharmacological as well as anthropological (ethnopharmacological) aspects of our research. We have identified taste and smell properties of medicinal (vs. non-medicinal) plants as important indigenous selection criteria. There exist well-defined criteria specific for each culture, which lead to the selection of a plant as a medicine. This field research has also formed a basis for studies on bioactive natural products from selected species. The bark of Guazuma ulmifolia showed antisecretory activity (cholera toxin-induced chloride secretion in rabbit distal colon in an USSING chamber). Active constituents are procyanidins with a polymerisation degree of eight or higher. Byrsonima crassifolia yielded proanthocyanidins with (+) epicatechin units and Baccharis conferta showed a dose-dependent antispasmodic effect with the effect being particularly strong in flavonoid-rich fractions. Our ethnopharmacological research led to the identification of sesquiterpene lactones (SLs) like parthenolide as potent and relatively specific inhibitors of the transcription factor NF-kappaB, an important mediator of the inflammatory process. The inhibitory effect of SLs is very strongly enhanced by the presence of such groups as the isoprenoid ring system, a lactone ring containing a conjugated exomethylene group (alpha-methylene-gamma-lactone) and an alpha,beta-unsaturated cyclopentenone or a conjugated ester moieties. Our work also elucidated the NF-kappaB inhibiting activity of the photosensitiser phaeophorbide A from Solanum diflorum (Solanaceae) in PMA induced HeLa cells. Hyptis verticillata yielded a series of lignans as well as sideritoflavone, rosmarinic acid and (R)-5-hydroxypyrrolidin-2-one and is rich in essential oil (rich in alpha-pinene, beta-pinene and thymol). Other species investigated include Begonia

  15. High Resolution Definition of Subsurface Heterogeneity for Understanding the Biodynamics of Natural Field Systems: Advancing the Ability for Scaling to Field Conditions

    International Nuclear Information System (INIS)

    Majer, Ernest L.; Brockman, Fred J.

    1999-01-01

    This research is an integrated project which uses physical (geophysical and hydrologic) and innovative geophysical imaging and microbial characterization methods to identify key scales of physical heterogeneities that affect bioremediation. In the this effort data from controlled laboratory and in situ experiments at the Idaho National Engineering and Environmental (INEEL) Test Area North (TAN) site were used to determine the dominant physical characteristics (lithologic, structural, and hydrologic) that can be imaged in situ and correlated with flow and transport properties. Emphasis was placed on identifying fundamental scales of variation of physical parameters that control transport behavior relative to subsurface microbial dynamics that could be used to develop a predictive model. A key hypothesis of the work was that nutrient flux and transport properties are key factors in controlling microbial dynamics, and that geophysical techniques could be used to identify the critical physical properties and scales controlling transport. This hypothesis was essentially validated. The goal was not only to develop and apply methods to monitor the spatial and temporal distribution of the bioremediation in fractured sites such as TAN, but also to develop methods applicable to a wider range of DOE sites. The outcome has been an improved understanding of the relationship between physical, chemical and microbial processes in heterogeneous environments, thus applicable to the design and monitoring of bioremediation strategies for a variety of environments. In this EMSP work we demonstrated that high resolution geophysical methods have considerable resolving power, especially when linked with modern advanced processing and interpretation. In terms of basic science, in addition to providing innovative methods for monitoring bioremediation, the work also provided a strong motivation for developing and extending high resolution geophysical methods

  16. Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 degrees S-77 degrees S using a pair-filter thermoluminescence method.

    Science.gov (United States)

    Nakajima, T; Kamiyama, T; Fujii, Y; Motoyama, H; Esumi, S

    1995-12-01

    Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antartica over the latitude range 69 degrees S - 77 degrees S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antartica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antartica consists mainly of cosmic rays.

  17. Comparison of toxicity and release rates of Cu and Zn from anti-fouling paints leached in natural and artificial brackish seawater.

    Science.gov (United States)

    Ytreberg, Erik; Karlsson, Jenny; Eklund, Britta

    2010-05-15

    Biocide-containing anti-fouling paints are regulated and approved according to the added active ingredients, such as Cu. Biocide-free paints are considered to be less environmentally damaging and do not need an approval. Zn, a common ingredient in paints with the potential of causing adverse effects has received only minor attention. Laboratory experiments were conducted in artificial brackish seawater (ASW) and natural brackish seawater (NSW) to quantify release rates of Cu and Zn from biocide-containing and biocide-free labeled eroding anti-fouling paints used on commercial vessels as well as leisure boats. In addition, organisms from three trophic levels, the crustacean Nitocra spinipes, the macroalga Ceramium tenuicorne and the bacteria Vibrio fischeri, were exposed to Cu and Zn to determine the toxicity of these metals. The release rate of Cu in NSW was higher from the paints for professional use (3.2-3.6 microg cm(-)(2)d(-1)) than from the biocide leaching leisure boat paint (1.1 microg cm(-)(2)d(-1)). Biocide-free paints did leach considerably more Zn (4.4-8.2 microg cm(-)(2)d(-1)) than biocide-containing leisure boat paint (3.0 microg cm(-)(2)d(-1)) and ship paints (0.7-2.0 microg cm(-)(2)d(-1)). In ASW the release rates of both metals were notably higher than in NSW for most tested paints. The macroalga was the most sensitive species to both Cu (EC(50)=6.4 microg l(-1)) and Zn (EC(50)=25 microg l(-1)) compared to the crustacean (Cu, LC(50)=2000 microg l(-1) Zn, LC(50)=890 microg l(-1)), and the bacteria (Cu, EC(50)=800 microg l(-1) and Zn, EC(50)=2000 microg l(-1)). The results suggest that the amounts of Zn and Cu leached from anti-fouling paints may attain toxic concentrations in areas with high boat density. To fully account for potential ecological risk associated with anti-fouling paints, Zn as well as active ingredients should be considered in the regulatory process. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Microbes in nature are limited by carbon and energy: the starving-survival lifestyle in soil and consequences for estimating microbial rates

    Directory of Open Access Journals (Sweden)

    John Eyres Hobbie

    2013-11-01

    Full Text Available Understanding microbial transformations in soils is important for predicting future carbon sequestration and nutrient cycling. This review questions some methods of assessing one key microbial process, the uptake of labile organic compounds. First, soil microbes have a starving-survival life style of dormancy, arrested activity, and low activity. Yet they are very abundant and remain poised to completely take up all substrates that become available. As a result, dilution assays with the addition of labeled substrates cannot be used. When labeled substrates are transformed into 14CO2, the first part of the biphasic release follows metabolic rules and is not affected by the environment. As a consequence, when identical amounts of isotopically substrates are added to soils from different climate zones, the same percentage of the substrate is respired and the same half-life of the respired 14CO2 from the labeled substrate is estimated. Second, when soils are sampled by a variety of methods from taking 10 cm diameter cores to millimeter-scale dialysis chambers, amino acids (and other organic compounds appear to be released by the severing of fine roots and mycorrhizal networks as well as from pressing or centrifuging treatments. As a result of disturbance as well as of natural root release, concentrations of individual amino acids of ~10 µM are measured. This contrasts with concentrations of a few nM found in aquatic systems and raises questions about possible differences in the bacterial strategy between aquatic and soil ecosystems. The small size of the hyphae (2-10 μm diameter and of the fine roots (0.2 to 2 mm diameter, make it very difficult to sample any volume of soil without introducing artifacts. Third, when micromolar amounts of labeled amino acids are added to soil, some of the isotope enters plant roots. This may be an artifact of the high µM concentrations applied.

  19. Microbes in nature are limited by carbon and energy: the starving-survival lifestyle in soil and consequences for estimating microbial rates.

    Science.gov (United States)

    Hobbie, John E; Hobbie, Erik A

    2013-01-01

    Understanding microbial transformations in soils is important for predicting future carbon sequestration and nutrient cycling. This review questions some methods of assessing one key microbial process, the uptake of labile organic compounds. First, soil microbes have a starving-survival life style of dormancy, arrested activity, and low activity. Yet they are very abundant and remain poised to completely take up all substrates that become available. As a result, dilution assays with the addition of labeled substrates cannot be used. When labeled substrates are transformed into (14)CO2, the first part of the biphasic release follows metabolic rules and is not affected by the environment. As a consequence, when identical amounts of isotopically substrates are added to soils from different climate zones, the same percentage of the substrate is respired and the same half-life of the respired (14)CO2 from the labeled substrate is estimated. Second, when soils are sampled by a variety of methods from taking 10 cm diameter cores to millimeter-scale dialysis chambers, amino acids (and other organic compounds) appear to be released by the severing of fine roots and mycorrhizal networks as well as from pressing or centrifuging treatments. As a result of disturbance as well as of natural root release, concentrations of individual amino acids of ~10 μM are measured. This contrasts with concentrations of a few nanomolar found in aquatic systems and raises questions about possible differences in the bacterial strategy between aquatic and soil ecosystems. The small size of the hyphae (2-10 μm diameter) and of the fine roots (0.2-2 mm diameter), make it very difficult to sample any volume of soil without introducing artifacts. Third, when micromolar amounts of labeled amino acids are added to soil, some of the isotope enters plant roots. This may be an artifact of the high micromolar concentrations applied.

  20. Understanding the complexity of the Lévy-walk nature of human mobility with a multi-scale cost∕benefit model.

    Science.gov (United States)

    Scafetta, Nicola

    2011-12-01

    human mobility, that the proposed model predicts the statistical properties of human mobility below 1 km ranges, where people just walk. In the latter case, the threshold between zone 1 and zone 2 may be around 100-200 m and, perhaps, may have been evolutionary determined by the natural human high resolution visual range, which characterizes an area of interest where the benefits are assumed to be randomly and uniformly distributed. This rich and suggestive interpretation of human mobility may characterize other complex random walk phenomena that may also be described by a N-piece fit Pareto distributions with increasing integer exponents. This study also suggests that distribution functions used to fit experimental probability distributions must be carefully chosen for not improperly obscuring the physics underlying a phenomenon.