Multihospital system management structure to meet the challenges of the 1980s.

PubMed

Lloyd, R W

1985-07-01

An improved operational structure is necessary to deal with today's rapidly changing health care environment. This article explores the alternatives for organizational structure that have been used to date and recommends modifications which will lead to more proactive management.

Enabling Rapid and Robust Structural Analysis During Conceptual Design

NASA Technical Reports Server (NTRS)

Eldred, Lloyd B.; Padula, Sharon L.; Li, Wu

2015-01-01

This paper describes a multi-year effort to add a structural analysis subprocess to a supersonic aircraft conceptual design process. The desired capabilities include parametric geometry, automatic finite element mesh generation, static and aeroelastic analysis, and structural sizing. The paper discusses implementation details of the new subprocess, captures lessons learned, and suggests future improvements. The subprocess quickly compares concepts and robustly handles large changes in wing or fuselage geometry. The subprocess can rank concepts with regard to their structural feasibility and can identify promising regions of the design space. The automated structural analysis subprocess is deemed robust and rapid enough to be included in multidisciplinary conceptual design and optimization studies.

Skeletal and dental effects of rapid maxillary expansion assessed through three-dimensional imaging: A multicenter study.

PubMed

Luebbert, Joshua; Ghoneima, Ahmed; Lagravère, Manuel O

2016-03-01

The aim of this study was to determine the skeletal and dental changes in rapid maxillary expansion treatments in two different populations assessed through cone-beam computer tomography (CBCT). Twenty-one patients from Edmonton, Canada and 16 patients from Cairo, Egypt with maxillary transverse deficiency (11-17 years old) were treated with a tooth-borne maxillary expander (Hyrax). CBCTs were obtained from each patient at two time points (initial T1 and at removal of appliance at 3-6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on skeletal and dental anatomical structures on the cranial base, maxilla and mandible. Descriptive statistics, intraclass correlation coefficients and one-way ANOVA analysis were used to determine if there were skeletal and dental changes and if these changes were statistically different between both populations. Descriptive statistics show that dental changes were larger than skeletal changes for both populations. Skeletal and dental changes between populations were not statistically different (P<0.05) from each other with the exception of the upper incisor proclination being larger in the Indiana group (P>0.05). Rapid maxillary expansion treatments in different populations demonstrate similar skeletal and dental changes. These changes are greater on the dental structures compared to the skeletal ones in a 4:1 ratio. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

Changes in geometrical and biomechanical properties of immature male and female rat tibia

NASA Technical Reports Server (NTRS)

Zernicke, Ronald F.; Hou, Jack C.-H.; Vailas, Arthur C.; Nishimoto, Mitchell; Patel, Sanjay

1990-01-01

The differences in the geometry and mechanical properties of immature male and female rat tibiae were detailed in order to provide comparative data for spaceflight, exercise, or disease experiments that use immature rats as an animal model. The experiment focuses on the particularly rapid period of growth that occurs in the Sprague-Dawley rat between 40 and 60 d of age. Tibial length and middiaphysical cross-sectional data were analyzed for eight different groups of rats according to age and sex, and tibial mechanical properties were obtained via three-point bending tests to failure. Results indicate that, during the 15 d period of rapid growth, changes in rat tibial geometry are more important than changes in bone material properties for influencing the mechanical properties of the tibia. Male tibiae changed primarily in structural properties, while in the female rats major changes in mechanical properties of the tibia were only attributable to changes in the structural properties of the bone.

Rapid Structural Design Change Evaluation with AN Experiment Based FEM

NASA Astrophysics Data System (ADS)

Chu, C.-H.; Trethewey, M. W.

1998-04-01

The work in this paper proposes a dynamic structural design model that can be developed in a rapid fashion. The approach endeavours to produce a simplified FEM developed in conjunction with an experimental modal database. The FEM is formulated directly from the geometry and connectivity used in an experimental modal test using beam/frame elements. The model sacrifices fine detail for a rapid development time. The FEM is updated at the element level so the dynamic response replicates the experimental results closely. The physical attributes of the model are retained, making it well suited to evaluate the effect of potential design changes. The capabilities are evaluated in a series of computational and laboratory tests. First, a study is performed with a simulated cantilever beam with a variable mass and stiffness distribution. The modal characteristics serve as the updating target with random noise added to simulate experimental uncertainty. A uniformly distributed FEM is developed and updated. The results show excellent results, all natural frequencies are within 0·001% with MAC values above 0·99. Next, the method is applied to predict the dynamic changes of a hardware portal frame structure for a radical design change. Natural frequency predictions from the original FEM differ by as much as almost 18% with reasonable MAC values. The results predicted from the updated model produce excellent results when compared to the actual hardware changes, the first five modal natural frequency difference is around 5% and the corresponding mode shapes producing MAC values above 0·98.

Resilient organizations: matrix model and service line management.

PubMed

Westphal, Judith A

2005-09-01

Resilient organizations modify structures to meet the demands of the marketplace. The author describes a structure that enables multihospital organizations to innovate and rapidly adapt to changes. Service line management within a matrix model is an evolving organizational structure for complex systems in which nurses are pivotal members.

ANALYSIS OF AQUATIC MICROBIAL COMMUNITIES IMPACTED BY LARGE POULTRY FORMS

EPA Science Inventory

Microbial communities often respond more rapidly and extensively to environmental change than communities of higher organisms. Thus, characterizing shifts in the structure of native bacterial communities as a response to changes in nutrients, antimicrobials, and invading pathogen...

Informing radiography curriculum development: The views of UK radiology service managers concerning the 'fitness for purpose' of recent diagnostic radiography graduates.

PubMed

Sloane, C; Miller, P K

2017-09-01

Recent years have seen significant changes in the way medical imaging services are delivered, rapid changes in technology and big increases in the number and ranges of examinations undertaken. Given these changes the study aimed to critically evaluate the fitness for purpose of newly qualified diagnostic radiography. The study employed a grounded theory approach to analyse the interviews of 20 radiology managers from a range of medical imaging providers across the UK. Four key themes emerged from the analysis. These were: curriculum content and structure review; diversification in the role of the radiographer; professionalism and coping and the reformation of career structures. The results indicate the role of the radiographer is now in a state of flux and challenge radiology managers and educators to design curricula and career structures which are better matched the role of the radiographer in the very rapidly changing technological, organisational and social contexts of modern society. Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

Comparison of dissimilarity measures for cluster analysis of X-ray diffraction data from combinatorial libraries

NASA Astrophysics Data System (ADS)

Iwasaki, Yuma; Kusne, A. Gilad; Takeuchi, Ichiro

2017-12-01

Machine learning techniques have proven invaluable to manage the ever growing volume of materials research data produced as developments continue in high-throughput materials simulation, fabrication, and characterization. In particular, machine learning techniques have been demonstrated for their utility in rapidly and automatically identifying potential composition-phase maps from structural data characterization of composition spread libraries, enabling rapid materials fabrication-structure-property analysis and functional materials discovery. A key issue in development of an automated phase-diagram determination method is the choice of dissimilarity measure, or kernel function. The desired measure reduces the impact of confounding structural data issues on analysis performance. The issues include peak height changes and peak shifting due to lattice constant change as a function of composition. In this work, we investigate the choice of dissimilarity measure in X-ray diffraction-based structure analysis and the choice of measure's performance impact on automatic composition-phase map determination. Nine dissimilarity measures are investigated for their impact in analyzing X-ray diffraction patterns for a Fe-Co-Ni ternary alloy composition spread. The cosine, Pearson correlation coefficient, and Jensen-Shannon divergence measures are shown to provide the best performance in the presence of peak height change and peak shifting (due to lattice constant change) when the magnitude of peak shifting is unknown. With prior knowledge of the maximum peak shifting, dynamic time warping in a normalized constrained mode provides the best performance. This work also serves to demonstrate a strategy for rapid analysis of a large number of X-ray diffraction patterns in general beyond data from combinatorial libraries.

Effects of rapid palatal expansion (RPE) and twin block mandibular advancement device (MAD) on pharyngeal structures in Class II pediatric patients from Cluj-Napoca, Romania.

PubMed

Rădescu, Ovidiu Dănuţ; Colosi, Horațiu Alexandru; Albu, Silviu

2018-05-23

To compare cephalometric changes of pharyngeal structures after rapid palatal expansion (RPE) with those induced by a twin block mandibular advancement device (MAD) with palatal expansion capability. This retrospective study investigated 55 Class II pediatric patients, divided into two groups: 29 patients treated with RPE and 26 patients treated with MAD. Lateral cephalometric measurements were compared before and after treatment. Changes in pharyngeal airway space were statistically significant in both groups (p < 0.001) from a pre-treatment mean distance measured between the lower posterior pharyngeal wall and the hyoid bone (LPF-H) of 25.42 mm in the MAD group and 28.62 mm in the RPE group, to a post-treatment mean LPF-H of 27.96 mm in the MAD group and 31.52 mm in the RPE group. Significant changes in pharyngeal space may be obtained in Class II patients through both rapid palatal expansion and mandibular advancement devices with palatal expansion capability.

Rapid forest change in the interior west presents analysis opportunities and challenges

Treesearch

John D. Shaw

2007-01-01

A recent drought has caused compositional and structural changes in Interior West forests. Recent periodic and annual inventory data provide an opportunity to analyze forest changes on a grand scale. This "natural experiment" also provides opportunities to test the effectiveness of Forest Inventory and Analysis (FIA) methodologies. It also presents some...

Alaska's Copper River: humankind in a changing world.

Treesearch

Harriet H. Christensen; J. Louise Mastrantonio; John C. Gordon; Bernard T. Bormann

2000-01-01

Opportunities for natural and social science research were assessed in the Copper River ecosystem including long-term, integrated studies of ecosystem structure and function. The ecosystem is one where change, often rapid, cataclysmic change, is the rule rather than the exception. The ecosystem also contains a variety of people pursuing various human purposes. Although...

An analysis of social consequences of rapid fertility decline in China.

PubMed

Liu, Z; Liu, L

1988-12-01

Rapid fertility decline in China has brought about 2 direct effects: 1) the natural increase of the population has slowed down, and 2) the age structure has changed from the young to the adult type. These 2 effects have caused a series of economic and social consequences. Rapid fertility decline increases the gross national product per capita and accelerates the improvement of people's lives. Rapid fertility decline slows population growth and speeds up the accumulation of capital and the development of the economy. Since 1981, accumulation growth has exceeded consumption growth. Fertility decline alleviates the enrollment pressure on primary and secondary schools, raises the efficiency of education funds, and promotes the popularization of education. The family planning program strengthens the maternal and child health care and the medical care systems. As the result of economic development, the people's nutritional levels are improving. The physical quality of teenagers has improved steadily. The change in the age structure will alleviate the tension of rapid population growth and benefit population control in the next century. Fertility decline forces the traditional attitude toward childbearing from "more children, more happiness" to improved quality of children. The rapid fertility decline has caused a great deal of concern both inside and outside China about the aging of the population. The labor force, however, will continue to grow for the next 60 years. At present, China's population problems are still those of population growth.

Transposable elements as agents of rapid adaptation may explain the genetic paradox of invasive species.

PubMed

Stapley, Jessica; Santure, Anna W; Dennis, Stuart R

2015-05-01

Rapid adaptation of invasive species to novel habitats has puzzled evolutionary biologists for decades, especially as this often occurs in the face of limited genetic variability. Although some ecological traits common to invasive species have been identified, little is known about the possible genomic/genetic mechanisms that may underlie their success. A common scenario in many introductions is that small founder population sizes will often lead to reduced genetic diversity, but that invading populations experience large environmental perturbations, such as changes in habitat and environmental stress. Although sudden and intense stress is usually considered in a negative context, these perturbations may actually facilitate rapid adaptation by affecting genome structure, organization and function via interactions with transposable elements (TEs), especially in populations with low genetic diversity. Stress-induced changes in TE activity can alter gene action and can promote structural variation that may facilitate the rapid adaptation observed in new environments. We focus here on the adaptive potential of TEs in relation to invasive species and highlight their role as powerful mutational forces that can rapidly create genetic diversity. We hypothesize that activity of transposable elements can explain rapid adaptation despite low genetic variation (the genetic paradox of invasive species), and provide a framework under which this hypothesis can be tested using recently developed and emerging genomic technologies. © 2015 John Wiley & Sons Ltd.

Soil microbial succession along a chronosequence on a High Arctic glacier foreland, Ny-Ålesund, Svalbard: 10 years' change

NASA Astrophysics Data System (ADS)

Yoshitake, Shinpei; Uchida, Masaki; Iimura, Yasuo; Ohtsuka, Toshiyuki; Nakatsubo, Takayuki

2018-06-01

Rapid glacial retreat in the High Arctic causes the expansion of new habitats, but the successional trajectories of soil microbial communities are not fully understood. We examined microbial succession along a chronosequence twice with a 10-year interval in a High Arctic glacier foreland. Soil samples were collected from five study sites with different ages and phospholipid fatty acids analysis was conducted to investigate the microbial biomass and community structure. Microbial biomass did not differ significantly between the two sampling times but tended to increase with the chronosequence and showed a significant correlation with soil carbon (C) and nitrogen (N) content. Microbial community structure clearly differed along the chronosequence and was correlated with C and N content. The largest shift in community structure over 10 years was observed in the newly exposed sites after deglaciation. The accumulation of soil organic matter was regarded as an important determinant both of microbial biomass and community structure over the successional period. In contrast, the initial microbial community on the newly exposed soil changed rapidly even in the High Arctic, suggesting that some key soil processes such as C and N cycling can also shift within the relatively short period after rapid glacial retreat.

Climate-driven regime shifts in Arctic marine benthos

PubMed Central

Kortsch, Susanne; Primicerio, Raul; Beuchel, Frank; Renaud, Paul E.; Rodrigues, João; Lønne, Ole Jørgen; Gulliksen, Bjørn

2012-01-01

Climate warming can trigger abrupt ecosystem changes in the Arctic. Despite the considerable interest in characterizing and understanding the ecological impact of rapid climate warming in the Arctic, few long time series exist that allow addressing these research goals. During a 30-y period (1980–2010) of gradually increasing seawater temperature and decreasing sea ice cover in Svalbard, we document rapid and extensive structural changes in the rocky-bottom communities of two Arctic fjords. The most striking component of the benthic reorganization was an abrupt fivefold increase in macroalgal cover in 1995 in Kongsfjord and an eightfold increase in 2000 in Smeerenburgfjord. Simultaneous changes in the abundance of benthic invertebrates suggest that the macroalgae played a key structuring role in these communities. The abrupt, substantial, and persistent nature of the changes observed is indicative of a climate-driven ecological regime shift. The ecological processes thought to drive the observed regime shifts are likely to promote the borealization of these Arctic marine communities in the coming years. PMID:22891319

Distortion of Local Atomic Structures in Amorphous Ge-Sb-Te Phase Change Materials

NASA Astrophysics Data System (ADS)

Hirata, A.; Ichitsubo, T.; Guan, P. F.; Fujita, T.; Chen, M. W.

2018-05-01

The local atomic structures of amorphous Ge-Sb-Te phase-change materials have yet to be clarified and the rapid crystal-amorphous phase change resulting in distinct optical contrast is not well understood. We report the direct observation of local atomic structures in amorphous Ge2Sb2Te5 using "local" reverse Monte Carlo modeling dedicated to an angstrom-beam electron diffraction analysis. The results corroborated the existence of local structures with rocksalt crystal-like topology that were greatly distorted compared to the crystal symmetry. This distortion resulted in the breaking of ideal octahedral atomic environments, thereby forming local disordered structures that basically satisfied the overall amorphous structure factor. The crystal-like distorted octahedral structures could be the main building blocks in the formation of the overall amorphous structure of Ge-Sb-Te.

Study of a splat cooled Cu-Zr-noncrystalline phase.

NASA Technical Reports Server (NTRS)

Revcolevschi, A.; Grant, N. J.

1972-01-01

By rapid quenching from the melt, using the splat forming gun technique, a noncrystalline phase has been obtained in a Cu-Zr alloy containing 60 at. % Cu. Upon heating, rapid crystallization of the samples takes place at 477 C with a heat release of about 700 cal per mol. The variation of the electrical resistivity of the samples with temperature confirms the transformation. Very high resolution electron microscopy studies of the structural changes of the samples upon heating are presented and show the gradual crystallization of the amorphous structure.

Altruistic aging: The evolutionary dynamics balancing longevity and evolvability.

PubMed

Herrera, Minette; Miller, Aaron; Nishimura, Joel

2017-04-01

Altruism is typically associated with traits or behaviors that benefit the population as a whole, but are costly to the individual. We propose that, when the environment is rapidly changing, senescence (age-related deterioration) can be altruistic. According to numerical simulations of an agent-based model, while long-lived individuals can outcompete their short lived peers, populations composed of long-lived individuals are more likely to go extinct during periods of rapid environmental change. Moreover, as in many situations where other cooperative behavior arises, senescence can be stabilized in a structured population.

The Challenges of Globalization: Changes in Education Policy and Practice in the Greek Context

ERIC Educational Resources Information Center

Vidali, Eva L.; Adams, Leah D.

2006-01-01

Globalization has been associated with rapid and significant changes in national and international politics and a growing complexity in economic and sociocultural realms. Inevitably, the new realities create pressures in social and economic structures that, in turn, shape changes at national levels. The field of education is drawn into these…

Influence of drought conditions on brown trout biomass and size structure in the Black Hills, South Dakota

USGS Publications Warehouse

James, Daniel A.; Wilhite, Jerry W.; Chipps, Steven R.

2010-01-01

We evaluated the influence of drought conditions on the biomass of brown trout Salmo trutta in Spearfish Creek, upper Rapid Creek, and lower Rapid Creek in the Black Hills of western South Dakota. Stream discharge, mean summer water temperature, the biomass of juvenile and adult brown trout, and brown trout size structure were compared between two time periods: early (2000–2002) and late drought (2005–2007). Mean summer water temperatures were similar between the early- and late-drought periods in Spearfish Creek (12.4°C versus 11.5°C), lower Rapid Creek (19.2°C versus 19.3°C), and upper Rapid Creek (9.8°C in both periods). In contrast, mean annual discharge differed significantly between the two time periods in Spearfish Creek (1.95 versus 1.50 m3/s), lower Rapid Creek (2.01 versus 0.94 m3/s), and upper Rapid Creek (1.41 versus 0.84 m3/s). The mean biomass of adult brown trout in all three stream sections was significantly higher in the early-drought than in the late-drought period (238 versus 69 kg/ha in Spearfish Creek, 272 versus 91 kg/ha in lower Rapid Creek, and 159 versus 32 kg/ha in upper Rapid Creek). The biomass of juvenile brown trout was similar (43 versus 23 kg/ha) in Spearfish Creek in the two periods, declined from 136 to 45 kg/ha in lower Rapid Creek, and increased from 14 to 73 kg/ha in upper Rapid Creek. Size structure did not differ between the early- and late-drought periods in lower Rapid and Spearfish creeks, but it did in upper Rapid Creek. In addition to drought conditions, factors such as angler harvest, fish movements, and the nuisance algal species Didymosphenia geminata are discussed as possible contributors to the observed changes in brown trout biomass and size structure in Black Hills streams.

The fine structure of Hadfield steel

NASA Astrophysics Data System (ADS)

Gulyaev, A. A.; Tyapkin, Yu. D.; Golikov, V. A.; Zharinova, V. S.

1985-06-01

Deformation of Hadfield steel commences by a dislocation mechanism which rapidly changes into a twinning mechanism for austenite which starts by one, and then by several, twinning systems {111} <112>.

Managerial Problems in the Use of Educational Technology in Primary Education Schools

ERIC Educational Resources Information Center

Hosgorur, Vural

2013-01-01

Rapid progress in science and technology also changes understanding, wishes and expectations, processes, operations and organisational structures. Such developments positively affect the structure of educational systems as well as learning-teaching activities in instructional environments. The problem of this research is to define managerial…

Structural Mass Spectrometry of Proteins Using Hydroxyl Radical Based Protein Footprinting

PubMed Central

Wang, Liwen; Chance, Mark R.

2011-01-01

Structural MS is a rapidly growing field with many applications in basic research and pharmaceutical drug development. In this feature article the overall technology is described and several examples of how hydroxyl radical based footprinting MS can be used to map interfaces, evaluate protein structure, and identify ligand dependent conformational changes in proteins are described. PMID:21770468

Managing Strategic Change through TQM: Learning from Failure.

ERIC Educational Resources Information Center

Redman, Tom; Grieves, Jim

1999-01-01

Case study of a manufacturing firm that implemented total quality management (TQM) found that the initiative may have failed because the company was undergoing rapid, radical structural change. Other problems included short-term focus, communication problems, and employee concerns about job security. TQM may be more compatible with continuous…

Innovative Credentialing: Employers Weigh in on Co-Curricular Transcripts

ERIC Educational Resources Information Center

Parks, Rodney; Taylor, Alexander

2016-01-01

The higher education landscape has changed significantly over the past decade as advances in technology and the proliferation of data have rapidly reshaped the work of the registrar. Despite these innovations, many registrars steadfastly resist changing the academic transcript, arguing that it must reflect the highly structured curriculum that…

Sustaining Emotional Resilience for School Leadership

ERIC Educational Resources Information Center

Steward, Julia

2014-01-01

Driven by the country's need to compete in a global economy, the UK government is imposing rapid and relentless educational change on schools. School leaders face the challenge of managing the impact of externally driven change and supporting others' resilience while frequently paying scant attention to their own. Six semi-structured interviews…

Improving Education and Training for Educational Administrators and Managers: Urgent Needs.

ERIC Educational Resources Information Center

Hughes, M. G.

This paper advocates giving urgent attention to improving the education and training of educational administrators and managers, realizing the need to respond to rapid and far-reaching political and social change worldwide, and to consequent change within national educational systems. The improvement of administrative structures and the…

Readings in Mass Communication; Concepts and Issues in the Mass Media.

ERIC Educational Resources Information Center

Emery, Michael C.; Smythe, Ted Curtis

The aim of this book of readings is to provide college students with a wide variety of articles on the rapid changes and problems of today's mass media. The problems of access, control, protection of sources, and relevance are considered crucial to the changing role of the media. Changes in the structure of both traditional media and new…

The Maker Movement, the Promise of Higher Education, and the Future of Work

ERIC Educational Resources Information Center

Wigner, Aubrey

2017-01-01

The 21st century will be the site of numerous changes in education systems in response to a rapidly evolving technological environment where existing skill sets and career structures may cease to exist or, at the very least, change dramatically. Likewise, the nature of work will also change to become more automated and more technologically…

The population in China’s earthquake-prone areas has increased by over 32 million along with rapid urbanization

NASA Astrophysics Data System (ADS)

He, Chunyang; Huang, Qingxu; Dou, Yinyin; Tu, Wei; Liu, Jifu

2016-07-01

Accurate assessments of the population exposed to seismic hazard are crucial in seismic risk mapping. Recent rapid urbanization in China has resulted in substantial changes in the size and structure of the population exposed to seismic hazard. Using the latest population census data and seismic maps, this work investigated spatiotemporal changes in the exposure of the population in the most seismically hazardous areas (MSHAs) in China from 1990 to 2010. In the context of rapid urbanization and massive rural-to-urban migration, nearly one-tenth of the Chinese population in 2010 lived in MSHAs. From 1990 to 2010, the MSHA population increased by 32.53 million at a significantly higher rate of change (33.6%) than the national average rate (17.7%). The elderly population in MSHAs increased by 81.4%, which is much higher than the group’s national growth rate of 58.9%. Greater attention should be paid to the demographic changes in earthquake-prone areas in China.

Temporal Fine Structure and Applications to Cochlear Implants

ERIC Educational Resources Information Center

Li, Xing

2013-01-01

Complex broadband sounds are decomposed by the auditory filters into a series of relatively narrowband signals, each of which conveys information about the sound by time-varying features. The slow changes in the overall amplitude constitute envelope, while the more rapid events, such as zero crossings, constitute temporal fine structure (TFS).…

Potential Utilization of Sweetgum and Yellow-Poplar for Structural Lumber

Treesearch

Timothy D. Faust; Robert H. McAlister; Stanley J. Zarnoch; Christopher B. Stephens

1991-01-01

The forest resource base in the Southeast is rapidly changing. Dwindling reserves of high quality pine sawlogs will provide incentive to utilize low-density hardwoods such as yellow-poplar and sweetgum for structural lumber. Inventories of sweetgum (Liquidambar styraciflua, L.) and yellow-poplar (Liriodendron tulipifera, L.) are currently high and growth is exceeding...

Potential Utilization of Sweetgum for Structural Lumber

Treesearch

Timothy D. Faust; Robert H. McAlister; Peter J. Stewart; Frederick W. Cubbage; Philip A. Araman

1991-01-01

The forest resource base in the Southeast is rapidly changing. Dwindling reserves of high quality pine sawlogs will provide incentive to utilize low-density hardwoods such as yellow-poplar and sweetgum for structural lumber. Inventories of sweetgum (Liquidambar styraciflua, L.) and yellow-poplar (Liriodendron tulipifera, L.) are currently high and growth is exceeding...

Audiovisual Simultaneity Judgment and Rapid Recalibration throughout the Lifespan.

PubMed

Noel, Jean-Paul; De Niear, Matthew; Van der Burg, Erik; Wallace, Mark T

2016-01-01

Multisensory interactions are well established to convey an array of perceptual and behavioral benefits. One of the key features of multisensory interactions is the temporal structure of the stimuli combined. In an effort to better characterize how temporal factors influence multisensory interactions across the lifespan, we examined audiovisual simultaneity judgment and the degree of rapid recalibration to paired audiovisual stimuli (Flash-Beep and Speech) in a sample of 220 participants ranging from 7 to 86 years of age. Results demonstrate a surprisingly protracted developmental time-course for both audiovisual simultaneity judgment and rapid recalibration, with neither reaching maturity until well into adolescence. Interestingly, correlational analyses revealed that audiovisual simultaneity judgments (i.e., the size of the audiovisual temporal window of simultaneity) and rapid recalibration significantly co-varied as a function of age. Together, our results represent the most complete description of age-related changes in audiovisual simultaneity judgments to date, as well as being the first to describe changes in the degree of rapid recalibration as a function of age. We propose that the developmental time-course of rapid recalibration scaffolds the maturation of more durable audiovisual temporal representations.

Annual reversible plasticity of feeding structures: cyclical changes of jaw allometry in a sea urchin

PubMed Central

Ebert, Thomas A.; Hernández, José Carlos; Clemente, Sabrina

2014-01-01

A wide variety of organisms show morphologically plastic responses to environmental stressors but in general these changes are not reversible. Though less common, reversible morphological structures are shown by a range of species in response to changes in predators, competitors or food. Theoretical analysis indicates that reversible plasticity increases fitness if organisms are long-lived relative to the frequency of changes in the stressor and morphological changes are rapid. Many sea urchin species show differences in the sizes of jaws (demi-pyramids) of the feeding apparatus, Aristotle's lantern, relative to overall body size, and these differences have been correlated with available food. The question addressed here is whether reversible changes of relative jaw size occur in the field as available food changes with season. Monthly samples of the North American Pacific coast sea urchin Strongylocentrotus purpuratus were collected from Gregory Point on the Oregon (USA) coast and showed an annual cycle of relative jaw size together with a linear trend from 2007 to 2009. Strongylocentrotus purpuratus is a long-lived species and under field conditions individuals experience multiple episodes of changes in food resources both seasonally and from year to year. Their rapid and reversible jaw plasticity fits well with theoretical expectations. PMID:24500161

Rapid Expectation Adaptation during Syntactic Comprehension

PubMed Central

Fine, Alex B.; Jaeger, T. Florian; Farmer, Thomas A.; Qian, Ting

2013-01-01

When we read or listen to language, we are faced with the challenge of inferring intended messages from noisy input. This challenge is exacerbated by considerable variability between and within speakers. Focusing on syntactic processing (parsing), we test the hypothesis that language comprehenders rapidly adapt to the syntactic statistics of novel linguistic environments (e.g., speakers or genres). Two self-paced reading experiments investigate changes in readers’ syntactic expectations based on repeated exposure to sentences with temporary syntactic ambiguities (so-called “garden path sentences”). These sentences typically lead to a clear expectation violation signature when the temporary ambiguity is resolved to an a priori less expected structure (e.g., based on the statistics of the lexical context). We find that comprehenders rapidly adapt their syntactic expectations to converge towards the local statistics of novel environments. Specifically, repeated exposure to a priori unexpected structures can reduce, and even completely undo, their processing disadvantage (Experiment 1). The opposite is also observed: a priori expected structures become less expected (even eliciting garden paths) in environments where they are hardly ever observed (Experiment 2). Our findings suggest that, when changes in syntactic statistics are to be expected (e.g., when entering a novel environment), comprehenders can rapidly adapt their expectations, thereby overcoming the processing disadvantage that mistaken expectations would otherwise cause. Our findings take a step towards unifying insights from research in expectation-based models of language processing, syntactic priming, and statistical learning. PMID:24204909

USA: Economics, Politics, Ideology, Number 12, December 1977

DTIC Science & Technology

1978-01-19

which will guarantee the pioneer firm the neces- sary profit level. The structure of market prices, however, represents a poor reflection, as we...the timely and rapid rearrangement of structural proportions. The economic mechanism of state-monopolistic capitalism, however, was incapable of...ensuring the necessary dynamism in the large-scale economy. The development of massive structural changes in the American economy is a complex and

High-resolution CT assessment of the pediatric airways: structure and function

NASA Astrophysics Data System (ADS)

Kramer, Sandra S.; Hoffman, Eric A.; Amirav, Israel

1994-05-01

The airway has always been a central focus for respiratory pathology in infants and children. Imaging of the larynx, trachea, and the central bronchi can be readily accomplished by radiographic or conventional CT techniques. Newer high resolution CT (HRCT) techniques have extended our view of the bronchi peripherally to the limits of scanner resolution, i.e., to bronchial generations 7 - 9, and rapid volumetric CT data acquisitions have made it possible to follow the same lung anatomic level through the rapidly occurring changes in a series of experimental protocols. These techniques together with a custom designed computer software program for image display and analysis have enabled us to objectively study changes in airway caliber and lung density that occurred in an animal mode of airway reactivity and thereby relate structure with function in the airways.

Marsh canopy structure changes and the Deepwater Horizon oil spill

USGS Publications Warehouse

Ramsey, Elijah W.; Rangoonwala, Amina; Jones, Cathleen E.

2016-01-01

Marsh canopy structure was mapped yearly from 2009 to 2012 in the Barataria Bay, Louisiana coastal region that was impacted by the 2010 Deepwater Horizon (DWH) oil spill. Based on the previously demonstrated capability of NASA's UAVSAR polarimetric synthetic aperture radar (PolSAR) image data to map Spartina alterniflora marsh canopy structure, structure maps combining the leaf area index (LAI) and leaf angle distribution (LAD, orientation) were constructed for yearly intervals that were directly relatable to the 2010 LAI-LAD classification. The yearly LAI-LAD and LAI difference maps were used to investigate causes for the previously revealed dramatic change in marsh structure from prespill (2009) to postspill (2010, spill cessation), and the occurrence of structure features that exhibited abnormal spatial and temporal patterns. Water level and salinity records showed that freshwater releases used to keep the oil offshore did not cause the rapid growth from 2009 to 2010 in marsh surrounding the inner Bay. Photointerpretation of optical image data determined that interior marsh patches exhibiting rapid change were caused by burns and burn recovery, and that the pattern of 2010 to 2011 LAI decreases in backshore marsh and extending along some tidal channels into the interior marsh were not associated with burns. Instead, the majority of 2010 to 2011 shoreline features aligned with vectors displaying the severity of 2010 shoreline oiling from the DWH spill. Although the association is not conclusive of a causal oil impact, the coexistent pattern is a significant discovery. PolSAR marsh structure mapping provided a unique perspective of marsh biophysical status that enhanced detection of change and monitoring of trends important to management effectiveness.

Electron irradiation effects on partially fluorinated polymer films: Structure-property relationships

NASA Astrophysics Data System (ADS)

Nasef, Mohamed Mahmoud; Dahlan, Khairul Zaman M.

2003-04-01

The effects of electron beam irradiation on two partially fluorinated polymer films i.e. poly(vinylidene fluoride) (PVDF) and poly(ethylene-tetrafluoroethylene) copolymer (ETFE) are studied at doses ranging from 100 to 1200 kGy in air at room temperature. Chemical structure, thermal and mechanical properties of irradiated films are investigated. FTIR show that both PVDF and ETFE films undergo similar changes in their chemical structures including the formation of carbonyl groups and double bonding. The changes in melting and crystallisation temperatures ( Tm and Tc) in both irradiated films are functions of irradiation dose and reflect the disorder in the chemical structure caused by the competition between crosslinking and chain scission. The heat of melting (Δ Hm) and the degree of crystallinity ( Xc) of PVDF films show no significant changes with the dose increase, whereas those of ETFE films are reduced rapidly after the first 100 kGy. The tensile strength of PVDF films is improved by irradiation compared to its rapid deterioration in ETFE films, which stemmed from the degradation prompted by the presence of radiation sensitive tetrafluoroethylene (TFE) comonomer units. The elongation at break of both films drops gradually with the dose increase indicating the formation of predominant crosslinked structures at high doses. However, the response of each polymer to crosslinking and main chain scission at various irradiation doses varies from PVDF to ETFE films.

Literacy Globalization and the Demand for Cultural Change Policy

ERIC Educational Resources Information Center

Peykani, Mehraban Hadi; Rad, Hadiyeh Tanhaie

2016-01-01

Rapid change has faced, information technology and communications world in the last two decades of the new type of illiteracy, failure to comply with the growth of the doctrine of technology on the one hand and lack of attention to retraining and learning. Traditional methods, educational structures, policies and governing policies and…

Maintenance of forest ecosystem health and vitality

Treesearch

Ryan D. DeSantis; W. Keith Moser

2016-01-01

Forest health will likely be threatened by a number of factors - including fragmentation, fire regime alteration, and a variety of diseases, insects, and invasive plants - along with global climate change (Krist et al. 2007, Tkacz et al. 2008). By itself, global climate change could dramatically and rapidly alter forest composition and structure (Allen and Breshears...

Social Change and Anomie: A Cross-National Study

ERIC Educational Resources Information Center

Zhao, Ruohui; Cao, Liqun

2010-01-01

We apply Durkheim's social transitional theory to explain the variation of anomie in 30 nations in the world. Combining data from two sources--the 1995 "World Values Survey and the United Nations University's World Income Inequality Database" or WIID--we test the hypothesis that rapid sociopolitical change at the structural level disrupts social…

The Changing Role of Students' Representation in Poland: An Historical Appraisal

ERIC Educational Resources Information Center

Antonowicz, Dominik; Pinheiro, Rómulo; Smuzewska, Marcelina

2014-01-01

Student representation in Poland has a relatively short but turbulent history. This article offers an historical appraisal of the development of student representation at the national level in the context of rapid and deep structural changes in Polish higher education. Based on a desktop analysis of official documentation, legislation, ideological…

Weight restoration therapy rapidly reverses cortical thinning in anorexia nervosa: A longitudinal study.

PubMed

Bernardoni, Fabio; King, Joseph A; Geisler, Daniel; Stein, Elisa; Jaite, Charlotte; Nätsch, Dagmar; Tam, Friederike I; Boehm, Ilka; Seidel, Maria; Roessner, Veit; Ehrlich, Stefan

2016-04-15

Structural magnetic resonance imaging studies have documented reduced gray matter in acutely ill patients with anorexia nervosa to be at least partially reversible following weight restoration. However, few longitudinal studies exist and the underlying mechanisms of these structural changes are elusive. In particular, the relative speed and completeness of brain structure normalization during realimentation remain unknown. Here we report from a structural neuroimaging study including a sample of adolescent/young adult female patients with acute anorexia nervosa (n=47), long-term recovered patients (n=34), and healthy controls (n=75). The majority of acutely ill patients were scanned longitudinally (n=35): at the beginning of standardized weight restoration therapy and again after partial weight normalization (>10% body mass index increase). High-resolution structural images were processed and analyzed with the longitudinal stream of FreeSurfer software to test for changes in cortical thickness and volumes of select subcortical regions of interest. We found globally reduced cortical thickness in acutely ill patients to increase rapidly (0.06 mm/month) during brief weight restoration therapy (≈3 months). This significant increase was predicted by weight restoration alone and could not be ascribed to potentially mediating factors such as duration of illness, hydration status, or symptom improvements. By comparing cortical thickness in partially weight-restored patients with that measured in healthy controls, we confirmed that cortical thickness had normalized already at follow-up. This pattern of thinning in illness and rapid normalization during weight rehabilitation was largely mirrored in subcortical volumes. Together, our findings indicate that structural brain insults inflicted by starvation in anorexia nervosa may be reversed at a rate much faster than previously thought if interventions are successful before the disorder becomes chronic. This provides evidence drawing previously speculated mechanisms such as (de-)hydration and neurogenesis into question and suggests that neuronal and/or glial remodeling including changes in macromolecular content may underlie the gray matter alterations observed in anorexia nervosa. Copyright © 2016 Elsevier Inc. All rights reserved.

Progression of structural lung disease on CT scans in children with cystic fibrosis related diabetes.

PubMed

Widger, John; Ranganathan, Sarath; Robinson, Philip J

2013-05-01

Diabetes has a deleterious effect on clinical status in children with Cystic Fibrosis (CF). We hypothesized that children with CF Related Diabetes (CFRD) or Impaired Glucose Tolerance (IGT) would have more rapidly progressive lung disease based on chest computed tomography (CT) than those with normal glucose tolerance (NGT). In a retrospective study we compared lung structure changes over time, as assessed by CT, in 34 CF children with CFRD, IGT or NGT. We then compared CT findings with changes in lung function. Percentage forced expiratory volume in 1s (%FEV1) remained stable over time with a mean (±SD) yearly change of -0.5% (±3.9), -0.4% (±2.3) and -0.85% (±2.8) (p=0.92) for the CFRD, IGT and NGT groups respectively. However, there was a mean (95%CI) increase in % CT score of 3.86%/year (1.77-5.95%), 1.59%/year (0.6-2.58%) and 1.09%/year (0.07-2.11%) (p=0.023). In patients with CFRD, there was a more rapid progression of structural lung disease, compared to those who had NGT that was not reflected by change in lung function. Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Oak, fire, and global change in the eastern USA: what might the future hold?

Treesearch

James M. Vose; Katherine Elliott

2016-01-01

The pace of environmental and socioeconomic change over the past 100 years has been rapid. Changes in fire regimes, climate, and land use have shaped the structure and function of most forest ecosystems, including oak (Quercus spp. L.) forests in the eastern United States.New stressors such as air pollution and invasive species have contributed to...

Rapid distortion theory and the 'problems' of turbulence

NASA Astrophysics Data System (ADS)

Hunt, J. C. R.; Carruthers, D. J.

1990-03-01

This paper describes some developments in the techniques of the rapid distortion theory (RDT) and in the general understanding of how it can be used. It is noted in particular that the theory provides a rational basis for analyzing rapidly changing turbulent flows (RCT), and a heuristic method for estimating certain features of slowly changing turbulent flows (SCT). Recent developments of the RDT are reviewed, including criteria for its validity and new solutions allowing for the effects of inhomogeneities and boundaries. The problems associated with analyzing different kinds of turbulent flow and different methods of solution are classified and discussed with reference to how the turbulent structure in a flow domain depends on the scale and geometry of the domain's boundary, and on the information provided in the boundary conditions.

The Persistence of Gender Earnings Inequality in Taiwan, 1978-1992.

ERIC Educational Resources Information Center

Zveglich, Joseph E., Jr.; And Others

1997-01-01

Despite rapid structural change in Taiwan, the gender earnings ratio between 1978-82 remained at 65%. Women's relative gains in education and experience were apparently offset by an increase in wage discrimination. (SK)

Oxygen Tuned Local Structure and Phase-Change Performance of Germanium Telluride.

PubMed

Zhou, Xilin; Du, Yonghua; Behera, Jitendra K; Wu, Liangcai; Song, Zhitang; Simpson, Robert E

2016-08-10

The effect of oxygen on the local structure of Ge atoms in GeTe-O materials has been investigated. Oxygen leads to a significant modification to the vibrational modes of Ge octahedra, which results from a decrease in its coordination. We find that a defective octahedral Ge network is the crucial fingerprint for rapid and reversible structural transitions in GeTe-based phase change materials. The appearance of oxide Raman modes confirms phase separation into GeO and TeO at high level O doping. Counterintuitively, despite the increase in crystallization temperature of oxygen doped GeTe-O phase change materials, when GeTe-O materials are used in electrical phase change memory cells, the electrical switching energy is lower than the pure GeTe material. This switching energy reduction is ascribed to the smaller change in volume, and therefore smaller enthalpy change, for the oxygen doped GeTe materials.

The rapid yellowing of spruce at a mountain site in the Central Black Forest (Germany). Combined effects of Mg deficiency and ozone on biochemical, physiological and structural properties of the chloroplasts.

PubMed

Siefermann-Harms, Dorothea; Boxler-Baldoma, Carmen; von Wilpert, Klaus; Heumann, Hans-Günther

2004-04-01

Biochemical, physiological and ultrastructural changes of the chloroplasts were examined in the course of the rapid yellowing process of spruce (Picea abies (L.) Karst.) at a Mg-deficient and ozone polluted mountain site (Schöllkopf mountain, Central Black Forest, Germany, 840 m a.s.l.). While at an early stage of yellowing the chlorophyll (Chl) content of the needles decreased slowly, significant changes occurred in the chloroplasts: The lability of the light-harvesting Chl a/b protein complex LHC II increased; the thylakoid cross-sectional area of chloroplasts in the outer mesophyll of the needles decreased, and their Chl fluorescence showed typical changes like the decrease of Fv/Fm and the increase of the photoinhibitory Fv quenching. Later on, the Chl content decreased rapidly, the changes in the chloroplasts continued and the needles turned yellow. Lutein and the pigments of the xanthophyll cycle were enhanced in relation to Chl a. Light and dark reactions of the xanthophyll cycle were highly active indicating efficient proton pumping and NADPH formation. The ratio of nonappressed to appressed thylakoid membranes increased with decreasing Fv/Fm suggesting that structural and fluorescence properties of the chloroplasts were related. The response of the needles to defined shading and improved Mg supply was also examined. The combined effects of strong sun light, low levels of non-Chl-bound Mg (Mg(free)) and ozone concentrations exceeding 80 microg m(-3) are shown to be necessary to induce the rapid yellowing process. For needles with Mg(free) < 0.12 mg g(-1) needle dry matter, the lability of the LHC II was correlated with the ozone concentration suggesting that the destabilization of the LHC II plays a central role in the rapid yellowing process.

Accurate high-throughput structure mapping and prediction with transition metal ion FRET

PubMed Central

Yu, Xiaozhen; Wu, Xiongwu; Bermejo, Guillermo A.; Brooks, Bernard R.; Taraska, Justin W.

2013-01-01

Mapping the landscape of a protein’s conformational space is essential to understanding its functions and regulation. The limitations of many structural methods have made this process challenging for most proteins. Here, we report that transition metal ion FRET (tmFRET) can be used in a rapid, highly parallel screen, to determine distances from multiple locations within a protein at extremely low concentrations. The distances generated through this screen for the protein Maltose Binding Protein (MBP) match distances from the crystal structure to within a few angstroms. Furthermore, energy transfer accurately detects structural changes during ligand binding. Finally, fluorescence-derived distances can be used to guide molecular simulations to find low energy states. Our results open the door to rapid, accurate mapping and prediction of protein structures at low concentrations, in large complex systems, and in living cells. PMID:23273426

Geographic patterns of genetic variation and population structure in Pinus aristata, Rocky Mountain bristlecone pine

Treesearch

Anna W. Schoettle; Betsy A. Goodrich; Valerie Hipkins; Christopher Richards; Julie Kray

2012-01-01

Pinus aristata Engelm., Rocky Mountain bristlecone pine, has a narrow core geographic and elevational distribution, occurs in disjunct populations, and is threatened by rapid climate change, white pine blister rust, and bark beetles. Knowledge of genetic diversity and population structure will help guide gene conservation strategies for this species. Sixteen sites...

Strength and Stiffness Properties of Sweetgum and Yellow-poplar Structural Lumber

Treesearch

Timothy D. Faust; Robert H. McAlister; Stanley J. Zarnoch

1990-01-01

The forest resource base in the Southeast is rapidly changing. Dwindling reserves of high quality pine sawlogs will provide incentives to utilize low-density hardwoods such as yellow-poplar and sweetgum for structural lumber. Inventories of sweetgum (Liriodendron tulipifera L.) are currently high and growth is exceeding removals. The mechanical propertiees of dimension...

Providing rapid feedback to residents on their teaching skills: an educational strategy for contemporary trainees.

PubMed

Katz-Sidlow, Rachel J; Baer, Tamar G; Gershel, Jeffrey C

2016-03-20

The objective of this study was to assess the attitudes of contemporary residents toward receiving rapid feedback on their teaching skills from their medical student learners. Participants consisted of 20 residents in their second post-graduate training year. These residents facilitated 44 teaching sessions with medical students within our Resident-as-Teacher program. Structured, written feedback from students was returned to the resident within 3 days following each session. Residents completed a short survey about the utility of the feedback, whether they would make a change to future teaching sessions based on the feedback, and what specifically they might change. The survey utilized a 4-point scale ("Not helpful/likely=1" to "Very helpful/likely=4"), and allowed for one free-text response. Free-text responses were hand-coded and underwent qualitative analysis to identify themes. There were 182 student feedback encounters resulting from 44 teaching sessions. The survey response rate was 73% (32/44). Ninety-four percent of residents rated the rapid feedback as "very helpful," and 91% would "very likely" make a change to subsequent sessions based on student feedback. Residents' proposed changes included modifications to session content and/or their personal teaching style. Residents found that rapid feedback received from medical student learners was highly valuable to them in their roles as teachers. A rapid feedback strategy may facilitate an optimal educational environment for contemporary trainees.

Justification of rapid prototyping in the development cycle of thermoplastic-based lab-on-a-chip.

PubMed

Preywisch, Regina; Ritzi-Lehnert, Marion; Drese, Klaus S; Röser, Tina

2011-11-01

During the developmental cycle of lab-on-a-chip devices, various microstructuring techniques are required. While in the designing and assay implementation phase direct structuring or so-called rapid-prototyping methods such as milling or laser ablation are applied, replication methods like hot embossing or injection moulding are favourable for large quantity manufacturing. This work investigated the applicability of rapid-prototyping techniques for thermoplastic chip development in general, and the reproducibility of performances in dependency of the structuring technique. A previously published chip for prenatal diagnosis that preconcentrates DNA via electrokinetic trapping and field-amplified-sample-stacking and afterwards separates it in CGE was chosen as a model. The impact of structuring, sealing, and the integration of membranes on the mobility of the EOF, DNA preconcentration, and DNA separation was studied. Structuring methods were found to significantly change the location where preconcentration of DNA occurs. However, effects on the mobility of the EOF and the separation quality of DNA were not observed. Exchange of the membrane has no effect on the chip performance, whereas the sealing method impairs the separation of DNA within the chip. The overall assay performance is not significantly influenced by different structuring methods; thus, the application of rapid-prototyping methods during a chip development cycle is well justified. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dominance of Endozoicomonas bacteria throughout coral bleaching and mortality suggests structural inflexibility of the Pocillopora verrucosa microbiome.

PubMed

Pogoreutz, Claudia; Rädecker, Nils; Cárdenas, Anny; Gärdes, Astrid; Wild, Christian; Voolstra, Christian R

2018-02-01

The importance of Symbiodinium algal endosymbionts and a diverse suite of bacteria for coral holobiont health and functioning are widely acknowledged. Yet, we know surprisingly little about microbial community dynamics and the stability of host-microbe associations under adverse environmental conditions. To gain insight into the stability of coral host-microbe associations and holobiont structure, we assessed changes in the community structure of Symbiodinium and bacteria associated with the coral Pocillopora verrucosa under excess organic nutrient conditions. Pocillopora -associated microbial communities were monitored over 14 days in two independent experiments. We assessed the effect of excess dissolved organic nitrogen (DON) and excess dissolved organic carbon (DOC). Exposure to excess nutrients rapidly affected coral health, resulting in two distinct stress phenotypes: coral bleaching under excess DOC and severe tissue sloughing (>90% tissue loss resulting in host mortality) under excess DON. These phenotypes were accompanied by structural changes in the Symbiodinium community. In contrast, the associated bacterial community remained remarkably stable and was dominated by two Endozoicomonas phylotypes, comprising on average 90% of 16S rRNA gene sequences. This dominance of Endozoicomonas even under conditions of coral bleaching and mortality suggests the bacterial community of P. verrucosa may be rather inflexible and thereby unable to respond or acclimatize to rapid changes in the environment, contrary to what was previously observed in other corals. In this light, our results suggest that coral holobionts might occupy structural landscapes ranging from a highly flexible to a rather inflexible composition with consequences for their ability to respond to environmental change.

Changing tree composition by life history strategy in a grassland-forest landscape

Treesearch

Brice B. Hanberry; John M. Kabrick; Hong S. He

2014-01-01

After rapid deforestation in the eastern United States, which generally occurred during the period of 1850-1920, forests did not return to historical composition and structure. We examined forest compositional change and then considered how historical land use and current land use may influence forests in a grassland-forest landscape, the Missouri Plains, where...

Constructing Disability in Bhutan: Schools, Structures, Policies, and Global Discourses

ERIC Educational Resources Information Center

Schuelka, Matthew John

2014-01-01

Bhutan is a small country in the Himalaya that has experienced rapid societal changes in the past 60 years. Perhaps the most significant change in Bhutan has occurred in its educational system, which grew from a very limited presence in 1961 to now serving the entire youth population of Bhutan. With this massive increase in educational service…

0-6723 : development of rapid, cement-based repair materials for transportation structures.

DOT National Transportation Integrated Search

2014-08-01

The state of Texas has been plagued by various : durability-related issues in recent years, : including deterioration from alkali-silica : reaction, delayed ettringite formation, corrosion : of reinforcing steel, volume changes (plastic : shrinkage, ...

Biomimetic FAA-certifiable, artificial muscle structures for commercial aircraft wings

NASA Astrophysics Data System (ADS)

Barrett, Ronald M.; Barrett, Cassandra M.

2014-07-01

This paper is centered on a new form of adaptive material which functions much in the same way as skeletal muscle tissue, is structurally modeled on plant actuator cells and capable of rapidly expanding or shrinking by as much as an order of magnitude in prescribed directions. Rapid changes of plant cell shape and sizes are often initiated via ion-transport driven fluid migration and resulting turgor pressure variation. Certain plant cellular structures like those in Mimosa pudica (sensitive plant), Albizia julibrissin (Mimosa tree), or Dionaea muscipula (Venus Flytrap) all exhibit actuation physiology which employs such turgor pressure manipulation. The paper begins with dynamic micrographs of a sectioned basal articulation joint from A. julibrissin. These figures show large cellular dimensional changes as the structure undergoes foliage articulation. By mimicking such structures in aircraft flight control mechanisms, extremely lightweight pneumatic control surface actuators can be designed. This paper shows several fundamental layouts of such surfaces with actuator elements made exclusively from FAA-certifiable materials, summarizes their structural mechanics and shows actuator power and energy densities that are higher than nearly all classes of conventional adaptive materials available today. A sample flap structure is shown to possess the ability to change its shape and structural stiffness as its cell pressures are manipulated, which in turn changes the surface lift-curve slope when exposed to airflows. Because the structural stiffness can be altered, it is also shown that the commanded section lift-curve slope can be similarly controlled between 1.2 and 6.2 rad-1. Several aircraft weight reduction principles are also shown to come into play as the need to concentrate loads to pass through point actuators is eliminated. The paper concludes with a summary of interrelated performance and airframe-level improvements including enhanced gust rejection, load alleviation, ride quality, fatigue life and flight safety.

Structural Evolution during Milling, Annealing, and Rapid Consolidation of Nanocrystalline Fe–10Cr–3Al Powder

PubMed Central

Kumar, Rajiv; Bakshi, S. R.; Joardar, Joydip; Parida, S.; Raja, V. S.; Singh Raman, R. K.

2017-01-01

Structural changes during the deformation-induced synthesis of nanocrystalline Fe–10Cr–3Al alloy powder via high-energy ball milling followed by annealing and rapid consolidation by spark plasma sintering were investigated. Reduction in crystallite size was observed during the synthesis, which was associated with the lattice expansion and rise in dislocation density, reflecting the generation of the excess grain boundary interfacial energy and the excess free volume. Subsequent annealing led to the exponential growth of the crystallites with a concomitant drop in the dislocation density. The rapid consolidation of the as-synthesized nanocrystalline alloy powder by the spark plasma sintering, on the other hand, showed only a limited grain growth due to the reduction of processing time for the consolidation by about 95% when compared to annealing at the same temperature. PMID:28772633

Is the MEDEVAC System Broke

DTIC Science & Technology

1992-03-23

17.- 9. Seri.7rity Classifications Self- p,•rformin(,;l ’,h.’ report ,, ’l .iatory F nto,’ U.S. Securily Classification in Bloc.k 9. % * •’, nrj/Mnnto...the Navy/Marine Corps structure and therefor could be rapidly improved. Though the medical issues addressed here are the result of information obtained...profession has become more complex. Tactical, logistical, and administrative doctrine has changed as rapidly as clinical medicine advances. If physicians and

Expansive Cements

DTIC Science & Technology

1970-10-01

plastic or semi- plastic concrete and place no stress on the restraint provided. If, on the other hand, the ettringite continues to form rapidly for too...yield, I and wp.ter-cement ratio. Such a change in cement content may cause a greater change in expansion caracteristics than the change in...the tendency toward plastic shrinkage is increased. During the w’nter znths most structural concrete installations hare had adequate heating and no

The role of fire in deep time ecosystems

NASA Astrophysics Data System (ADS)

Scott, Andrew C.; Bond, William J.; Collinson, Margaret E.; Glasspool, Ian J.; Brown, Sarah; Braman, Dennis R.

2010-05-01

Fires are very widespread in the world today and fire has also been common in the deep past. Fire is important in structuring contemporary World vegetation maintaining extensive open vegetation where the climate has the potential to support closed forests. The influence of fire on the structure of vegetation and plant traits present in a community vary depending on the fire regime. The fire regime is the characteristic pattern of fire frequency, severity (amount of biomass removed) and spatial extent. Fire regimes depend on the synergy between external physical factors and the properties of vegetation. Changes in the fire regime can be brought about by changes in external conditions such as climate, but also by changes in vegetation such as changes in flammability or productivity that influence the amount of fuel. For example, invasion of grasses into closed wooded habitats has initiated a ‘grass fire cycle' in many parts of the world triggering cascading changes in vegetation structure and composition from forest to open grassland or savanna woodland. The spread of flammable invasive species, especially grasses, has even altered fire regimes of fire-dependent flammable communities causing catastrophic ecosystem changes. We suggest that the spread of angiosperms in the Cretaceous was promoted by the development of novel fire regimes linked to the evolution of novel, highly productive (and flammable) plants. Within the limits of physical constraints on fire occurrence, Cretaceous angiosperms would have initiated a positive feedback analogous to the grass-fire cycle rapidly accumulating fuel that promoted more frequent fires, which maintained open habitats in which rapid growth-traits of angiosperms would be most favoured promoting rapid fuel accumulation etc. Frequent fires would have altered vegetation structure and composition both by increasing mortality rates of fire-damaged trees and reducing recruitment rates of seedlings and saplings where fires recurred before juveniles had reached "fire-proof" sizes. The effect would be to create more open conditions favouring plants with the angiosperm innovations of high photosynthetic rates, rapid maturation and rapid reproduction relative to gymnosperms. Fire has some analogies to large vertebrate herbivory, particularly in the potential to open forests and create habitat for low-growing sun-loving plants over extensive areas. The role of fire in favouring low-growing ‘ruderal', plants of open habitats is similar to that proposed for dinosaurs. A switch from high-browsing dinosaurs in the Jurassic to low-browsing dinosaurs in the Cretaceous has been noted and it has been argued that the switch in browse height would favour fast-growing angiosperms. The dinosaur hypothesis has recently been tested and found wanting, for example in the timing and coincidence of angiosperm abundance and low vs. high-browsing dinosaurs. Our research of the co-occurrence of dinosaur remains and charcoal assemblages in Dinosaur Provincial Park, Alberta, has suggested that it was a dominance of gymnospermous, woody vegetation that was ravaged by fire. In addition, the co-occurrence of dinosaur remains and charcoal is significant in demonstrating that the some dinosaur bone beds may have formed as a result of extensive post-fire erosion/rapid deposition cycles. In this paper we consider the evidence for and against fire as a major factor promoting vegetation change and angiosperm spread in the Cretaceous.

A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

DOE PAGES

Schoville, Sean D.; Chen, Yolanda H.; Andersson, Martin N.; ...

2018-01-31

The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome andmore » are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. In conclusion, the L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest.« less

A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoville, Sean D.; Chen, Yolanda H.; Andersson, Martin N.

The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome andmore » are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. In conclusion, the L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest.« less

A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae).

PubMed

Schoville, Sean D; Chen, Yolanda H; Andersson, Martin N; Benoit, Joshua B; Bhandari, Anita; Bowsher, Julia H; Brevik, Kristian; Cappelle, Kaat; Chen, Mei-Ju M; Childers, Anna K; Childers, Christopher; Christiaens, Olivier; Clements, Justin; Didion, Elise M; Elpidina, Elena N; Engsontia, Patamarerk; Friedrich, Markus; García-Robles, Inmaculada; Gibbs, Richard A; Goswami, Chandan; Grapputo, Alessandro; Gruden, Kristina; Grynberg, Marcin; Henrissat, Bernard; Jennings, Emily C; Jones, Jeffery W; Kalsi, Megha; Khan, Sher A; Kumar, Abhishek; Li, Fei; Lombard, Vincent; Ma, Xingzhou; Martynov, Alexander; Miller, Nicholas J; Mitchell, Robert F; Munoz-Torres, Monica; Muszewska, Anna; Oppert, Brenda; Palli, Subba Reddy; Panfilio, Kristen A; Pauchet, Yannick; Perkin, Lindsey C; Petek, Marko; Poelchau, Monica F; Record, Éric; Rinehart, Joseph P; Robertson, Hugh M; Rosendale, Andrew J; Ruiz-Arroyo, Victor M; Smagghe, Guy; Szendrei, Zsofia; Thomas, Gregg W C; Torson, Alex S; Vargas Jentzsch, Iris M; Weirauch, Matthew T; Yates, Ashley D; Yocum, George D; Yoon, June-Sun; Richards, Stephen

2018-01-31

The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome and are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. The L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest.

Liquid-induced colour change in a beetle: the concept of a photonic cell.

PubMed

Mouchet, Sébastien R; Van Hooijdonk, Eloise; Welch, Victoria L; Louette, Pierre; Colomer, Jean-François; Su, Bao-Lian; Deparis, Olivier

2016-01-13

The structural colour of male Hoplia coerulea beetles is notable for changing from blue to green upon contact with water. In fact, reversible changes in both colour and fluorescence are induced in this beetle by various liquids, although the mechanism has never been fully explained. Changes enacted by water are much faster than those by ethanol, in spite of ethanol's more rapid spread across the elytral surface. Moreover, the beetle's photonic structure is enclosed by a thin scale envelope preventing direct contact with the liquid. Here, we note the presence of sodium, potassium and calcium salts in the scale material that mediate the penetration of liquid through putative micropores. The result leads to the novel concept of a "photonic cell": namely, a biocompatible photonic structure that is encased by a permeable envelope which mediates liquid-induced colour changes in that photonic structure. Engineered photonic cells dispersed in culture media could revolutionize the monitoring of cell-metabolism.

Liquid-induced colour change in a beetle: the concept of a photonic cell

PubMed Central

Mouchet, Sébastien R.; Van Hooijdonk, Eloise; Welch, Victoria L.; Louette, Pierre; Colomer, Jean-François; Su, Bao-Lian; Deparis, Olivier

2016-01-01

The structural colour of male Hoplia coerulea beetles is notable for changing from blue to green upon contact with water. In fact, reversible changes in both colour and fluorescence are induced in this beetle by various liquids, although the mechanism has never been fully explained. Changes enacted by water are much faster than those by ethanol, in spite of ethanol’s more rapid spread across the elytral surface. Moreover, the beetle’s photonic structure is enclosed by a thin scale envelope preventing direct contact with the liquid. Here, we note the presence of sodium, potassium and calcium salts in the scale material that mediate the penetration of liquid through putative micropores. The result leads to the novel concept of a “photonic cell”: namely, a biocompatible photonic structure that is encased by a permeable envelope which mediates liquid-induced colour changes in that photonic structure. Engineered photonic cells dispersed in culture media could revolutionize the monitoring of cell-metabolism. PMID:26758681

Camera Systems Rapidly Scan Large Structures

NASA Technical Reports Server (NTRS)

2013-01-01

Needing a method to quickly scan large structures like an aircraft wing, Langley Research Center developed the line scanning thermography (LST) system. LST works in tandem with a moving infrared camera to capture how a material responds to changes in temperature. Princeton Junction, New Jersey-based MISTRAS Group Inc. now licenses the technology and uses it in power stations and industrial plants.

77 FR 40683 - Self-Regulatory Organizations; New York Stock Exchange LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-10

... evolution of the equities markets away from manual executions and manual enforcement of rules toward an... Exchange's current market structure and to reflect rapidly changing market technology and the development...

Solid Modeling of Crew Exploration Vehicle Structure Concepts for Mass Optimization

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

2006-01-01

Parametric solid and surface models of the crew exploration vehicle (CEV) command module (CM) structure concepts are developed for rapid finite element analyses, structural sizing and estimation of optimal structural mass. The effects of the structural configuration and critical design parameters on the stress distribution are visualized, examined to arrive at an efficient design. The CM structural components consisted of the outer heat shield, inner pressurized crew cabin, ring bulkhead and spars. For this study only the internal cabin pressure load case is considered. Component stress, deflection, margins of safety and mass are used as design goodness criteria. The design scenario is explored by changing the component thickness parameters and materials until an acceptable design is achieved. Aluminum alloy, titanium alloy and an advanced composite material properties are considered for the stress analysis and the results are compared as a part of lessons learned and to build up a structural component sizing knowledge base for the future CEV technology support. This independent structural analysis and the design scenario based optimization process may also facilitate better CM structural definition and rapid prototyping.

Linking Precursor Alterations to Nanoscale Structure and Optical Transparency in Polymer Assisted Fast-Rate Dip-Coating of Vanadium Oxide Thin Films

PubMed Central

Glynn, Colm; Creedon, Donal; Geaney, Hugh; Armstrong, Eileen; Collins, Timothy; Morris, Michael A.; Dwyer, Colm O’

2015-01-01

Solution processed metal oxide thin films are important for modern optoelectronic devices ranging from thin film transistors to photovoltaics and for functional optical coatings. Solution processed techniques such as dip-coating, allow thin films to be rapidly deposited over a large range of surfaces including curved, flexible or plastic substrates without extensive processing of comparative vapour or physical deposition methods. To increase the effectiveness and versatility of dip-coated thin films, alterations to commonly used precursors can be made that facilitate controlled thin film deposition. The effects of polymer assisted deposition and changes in solvent-alkoxide dilution on the morphology, structure, optoelectronic properties and crystallinity of vanadium pentoxide thin films was studied using a dip-coating method using a substrate withdrawal speed within the fast-rate draining regime. The formation of sub-100 nm thin films could be achieved rapidly from dilute alkoxide based precursor solutions with high optical transmission in the visible, linked to the phase and film structure. The effects of the polymer addition was shown to change the crystallized vanadium pentoxide thin films from a granular surface structure to a polycrystalline structure composed of a high density of smaller in-plane grains, resulting in a uniform surface morphology with lower thickness and roughness. PMID:26123117

The effect of nutrient deposition on bacterial communities in Arctic tundra soil

Treesearch

Barbara J. Campbell; Shawn W. Polson; Thomas E. Hanson; Michelle C. Mack; Edward A.G. Schuur

2010-01-01

The microbial communities of high-latitude ecosystems are expected to experience rapid changes over the next century due to climate warming and increased deposition of reactive nitrogen, changes that will likely affect microbial community structure and function. In moist acidic tundra (MAT) soils on the North Slope of the Brooks Range, Alaska, substantial losses of C...

Red oak decline and mortality by ecological land type in the Missouri ozarks

Treesearch

John M. Fan Kabrick; Stephen R. Shifley

2007-01-01

Oak decline, the precipitous mortality of mature oak trees, has been a chronic problem in xeric oak ecosystems and is reaching unprecedented levels in red oak group (Quercus section Lobatae) species in the Ozark Highlands. The high rates of mortality are leading to rapid changes in species composition, forest structure, and related changes in fire...

Variation in genetic structure and gene flow across the range of Sequoiadendron giganteum (giant sequoia)

Treesearch

Rainbow DeSilva; Richard S. Dodd

2017-01-01

During this century, climate warming and altered precipitation patterns will lead to habitat changes that may be beneficial to some long-lived tree species and detrimental to others. Paleoendemics, with limited and disjunct distributions will face the greatest challenges, as migration rates will be too slow to keep pace with rapid environmental change and populations...

Interplay between past market correlation structure changes and future volatility outbursts.

PubMed

Musmeci, Nicoló; Aste, Tomaso; Di Matteo, T

2016-11-18

We report significant relations between past changes in the market correlation structure and future changes in the market volatility. This relation is made evident by using a measure of "correlation structure persistence" on correlation-based information filtering networks that quantifies the rate of change of the market dependence structure. We also measured changes in the correlation structure by means of a "metacorrelation" that measures a lagged correlation between correlation matrices computed over different time windows. Both methods show a deep interplay between past changes in correlation structure and future changes in volatility and we demonstrate they can anticipate market risk variations and this can be used to better forecast portfolio risk. Notably, these methods overcome the curse of dimensionality that limits the applicability of traditional econometric tools to portfolios made of a large number of assets. We report on forecasting performances and statistical significance of both methods for two different equity datasets. We also identify an optimal region of parameters in terms of True Positive and False Positive trade-off, through a ROC curve analysis. We find that this forecasting method is robust and it outperforms logistic regression predictors based on past volatility only. Moreover the temporal analysis indicates that methods based on correlation structural persistence are able to adapt to abrupt changes in the market, such as financial crises, more rapidly than methods based on past volatility.

Interplay between past market correlation structure changes and future volatility outbursts

NASA Astrophysics Data System (ADS)

Musmeci, Nicoló; Aste, Tomaso; Di Matteo, T.

2016-11-01

We report significant relations between past changes in the market correlation structure and future changes in the market volatility. This relation is made evident by using a measure of “correlation structure persistence” on correlation-based information filtering networks that quantifies the rate of change of the market dependence structure. We also measured changes in the correlation structure by means of a “metacorrelation” that measures a lagged correlation between correlation matrices computed over different time windows. Both methods show a deep interplay between past changes in correlation structure and future changes in volatility and we demonstrate they can anticipate market risk variations and this can be used to better forecast portfolio risk. Notably, these methods overcome the curse of dimensionality that limits the applicability of traditional econometric tools to portfolios made of a large number of assets. We report on forecasting performances and statistical significance of both methods for two different equity datasets. We also identify an optimal region of parameters in terms of True Positive and False Positive trade-off, through a ROC curve analysis. We find that this forecasting method is robust and it outperforms logistic regression predictors based on past volatility only. Moreover the temporal analysis indicates that methods based on correlation structural persistence are able to adapt to abrupt changes in the market, such as financial crises, more rapidly than methods based on past volatility.

Interplay between past market correlation structure changes and future volatility outbursts

PubMed Central

Musmeci, Nicoló; Aste, Tomaso; Di Matteo, T.

2016-01-01

We report significant relations between past changes in the market correlation structure and future changes in the market volatility. This relation is made evident by using a measure of “correlation structure persistence” on correlation-based information filtering networks that quantifies the rate of change of the market dependence structure. We also measured changes in the correlation structure by means of a “metacorrelation” that measures a lagged correlation between correlation matrices computed over different time windows. Both methods show a deep interplay between past changes in correlation structure and future changes in volatility and we demonstrate they can anticipate market risk variations and this can be used to better forecast portfolio risk. Notably, these methods overcome the curse of dimensionality that limits the applicability of traditional econometric tools to portfolios made of a large number of assets. We report on forecasting performances and statistical significance of both methods for two different equity datasets. We also identify an optimal region of parameters in terms of True Positive and False Positive trade-off, through a ROC curve analysis. We find that this forecasting method is robust and it outperforms logistic regression predictors based on past volatility only. Moreover the temporal analysis indicates that methods based on correlation structural persistence are able to adapt to abrupt changes in the market, such as financial crises, more rapidly than methods based on past volatility. PMID:27857144

Eco-evolution in size-structured ecosystems: simulation case study of rapid morphological changes in alewife.

PubMed

Kang, Jung Koo; Thibert-Plante, Xavier

2017-02-27

Over the last 300 years, interactions between alewives and zooplankton communities in several lakes in the U.S. have caused the alewives' morphology to transition rapidly from anadromous to landlocked. Lakes with landlocked alewives contain smaller-bodied zooplankton than those without alewives. Landlocked adult alewives display smaller body sizes, narrower gapes, smaller inter-gill-raker spacings, reach maturity at an earlier age, and are less fecund than anadromous alewives. Additionally, landlocked alewives consume pelagic prey exclusively throughout their lives whereas anadromous alewives make an ontogenetic transition from pelagic to littoral prey. These rapid, well-documented changes in the alewives' morphology provide important insights into the morphological evolution of fish. Predicting the morphological evolution of fish is crucial for fisheries and ecosystem management, but the involvement of multiple trophic interactions make predictions difficult. To obtain an improved understanding of rapid morphological change in fish, we developed an individual-based model that simulated rapid changes in the body size and gill-raker count of a fish species in a hypothetical, size-structured prey community. Model parameter values were based mainly on data from empirical studies on alewives. We adopted a functional trait approach; consequently, the model explicitly describes the relationships between prey body size, alewife body size, and alewife gill-raker count. We sought to answer two questions: (1) How does the impact of alewife populations on prey feed back to impact alewife size and gill raker number under several alternative scenarios? (2) Will the trajectory of the landlocked alewives' morphological evolution change after 150-300 years in freshwater? Over the first 250 years, the alewives' numbers of gill-rakers only increased when reductions in their body size substantially improved their ability to forage for small prey. Additionally, alewives' gill-raker counts increased more rapidly as the adverse effects of narrow gill-raker spacings on foraging for large prey were made less severe. For the first 150-250 years, alewives' growth decreased monotonically, and their gill-raker number increased monotonically. After the first 150-250 years, however, the alewives exhibited multiple evolutionary morphological trajectories in different trophic settings. In several of these settings, their evolutionary trajectories even reversed after the first 150-250 years. Alewives affected the abundance and morphology of their prey, which in turn changed the abundance and morphology of the alewives. Complex low-trophic-level interactions can alter the abundance and characteristics of alewives. This study suggests that the current morphology of recently (∼300 years)-landlocked alewives may not represent an evolutionarily stable state.

Providing rapid feedback to residents on their teaching skills: an educational strategy for contemporary trainees

PubMed Central

Baer, Tamar G.; Gershel, Jeffrey C.

2016-01-01

Objectives The objective of this study was to assess the attitudes of contemporary residents toward receiving rapid feedback on their teaching skills from their medical student learners. Methods Participants consisted of 20 residents in their second post-graduate training year. These residents facilitated 44 teaching sessions with medical students within our Resident-as-Teacher program. Structured, written feedback from students was returned to the resident within 3 days following each session. Residents completed a short survey about the utility of the feedback, whether they would make a change to future teaching sessions based on the feedback, and what specifically they might change. The survey utilized a 4-point scale (“Not helpful/likely=1” to “Very helpful/likely=4”), and allowed for one free-text response. Free-text responses were hand-coded and underwent qualitative analysis to identify themes.   Results There were 182 student feedback encounters resulting from 44 teaching sessions. The survey response rate was 73% (32/44). Ninety-four percent of residents rated the rapid feedback as “very helpful,” and 91% would “very likely” make a change to subsequent sessions based on student feedback. Residents’ proposed changes included modifications to session content and/or their personal teaching style.    Conclusions Residents found that rapid feedback received from medical student learners was highly valuable to them in their roles as teachers. A rapid feedback strategy may facilitate an optimal educational environment for contemporary trainees. PMID:26995390

Evaluation of the July, 1980, SCRTD (Los Angeles) Fare Increase

DOT National Transportation Integrated Search

1982-09-01

This report presents an evaluation of the July 1980 fare structure revision planned and implemented by the Southern California Rapid Transit District (SCRTD). The changes included increases in both cash fares and monthly pass prices for different use...

Experimental Investigations on Effect of Damage on Vibration Characteristics of a Reinforced Concrete Beam

NASA Astrophysics Data System (ADS)

Srinivas, V.; Jeyasehar, C. Antony; Ramanjaneyulu, K.; Sasmal, Saptarshi

2012-02-01

Need for developing efficient non-destructive damage assessment procedures for civil engineering structures is growing rapidly towards structural health assessment and management of existing structures. Damage assessment of structures by monitoring changes in the dynamic properties or response of the structure has received considerable attention in recent years. In the present study, damage assessment studies have been carried out on a reinforced concrete beam by evaluating the changes in vibration characteristics with the changes in damage levels. Structural damage is introduced by static load applied through a hydraulic jack. After each stage of damage, vibration testing is performed and system parameters were evaluated from the measured acceleration and displacement responses. Reduction in fundamental frequencies in first three modes is observed for different levels of damage. It is found that a consistent decrease in fundamental frequency with increase in damage magnitude is noted. The beam is numerically simulated and found that the vibration characteristics obtained from the measured data are in close agreement with the numerical data.

The impacts of rapid demographic transition on family structure and income inequality in Brazil, 1981-2011.

PubMed

Maia, Alexandre Gori; Sakamoto, Camila Strobl

2016-11-01

This study analysed the impact of changing family structure on income distribution. Specifically, it analysed how changes in the proportions of different categories of family in the population contributed to increases in the income of the richest and poorest social strata in Brazil, and the consequent impacts on income inequality. Rural and urban families were compared in order to understand how these dynamics had different impacts on more developed (urban) and less developed (rural) areas. The results emphasize how changes observed in family structure are more pronounced among the richest families, contributing to an increase in (i) the income of the richest families and (ii) income inequality between the richest and poorest families, as well as between urban and rural areas.

Changes in methane emission and microbial community structure in a Phragmites australis-expanding tidal marsh of a temperature region

NASA Astrophysics Data System (ADS)

Kim, J.; Lee, J.; Kang, H.

2017-12-01

Phragmites australis is one of the representative vegetation of coastal wetlands which is distributed in North America, East Asia and European Countries. In North America, P. australis has invaded large areas of coastal wetlands, which causes various ecological problems such as increases in methane emission and reduction in biodiversity. In South Korea, P. australis is rapidly expanded in tidal marshes in Suncheon Bay. The expansion of P. australis enhanced methane emission by increasing dissolved organic carbon and soil moisture, and changing in relative abundances of methanogen, methanotroph, and sulfate reducing bacteria. Microbial community structure might be also shifted and affect methane cycle, but accurate observation on microbial community structure has not been fully illustrated yet. Therefore, we tried to monitor the changing microbial community structure due to P. australis expansion by using Next Generation Sequencing (NGS). NGS results showed that microbial community was substantially changed with the expansion. We also observed seasonal variations and chronosequence of microbial community structures along the expansion of P. australis, which showed distinctive changing patterns. P. australis expansion substantially affected microbial community structure in tidal marsh which may play an important role in methane cycle in tidal marshes.

Research in nonlinear structural and solid mechanics

NASA Technical Reports Server (NTRS)

Mccomb, H. G., Jr. (Compiler); Noor, A. K. (Compiler)

1981-01-01

Recent and projected advances in applied mechanics, numerical analysis, computer hardware and engineering software, and their impact on modeling and solution techniques in nonlinear structural and solid mechanics are discussed. The fields covered are rapidly changing and are strongly impacted by current and projected advances in computer hardware. To foster effective development of the technology perceptions on computing systems and nonlinear analysis software systems are presented.

The Influence of Financial, Human and Social Capital on Japanese Men's and Women's Health in Single- and Two-Parent Family Structures

ERIC Educational Resources Information Center

Bassani, Cherylynn

2008-01-01

Large-scale demographic changes have been occurring in Japan over the last few decades. During this time, the proportion of two-parent (nuclear) and single-parent families have doubled. Despite this rapid increase, the health of individuals in these family structures have received limited attention, as the focus has been directed towards the…

Changes in DNA methylation fingerprint of Quercus ilex trees in response to experimental field drought simulating projected climate change.

PubMed

Rico, L; Ogaya, R; Barbeta, A; Peñuelas, J

2014-03-01

Rapid genetic changes in plants have been reported in response to current climate change. We assessed the capacity of trees in a natural forest to produce rapid acclimation responses based on epigenetic modifications. We analysed natural populations of Quercus ilex, the dominant tree species of Mediterranean forests, using the methylation-sensitive amplified polymorphism (MSAP) technique to assess patterns and levels of methylation in individuals from unstressed forest plots and from plots experimentally exposed to drought for 12 years at levels projected for the coming decades. The percentage of hypermethylated loci increased, and the percentage of fully methylated loci clearly decreased in plants exposed to drought. Multivariate analyses exploring the status of methylation at MSAP loci also showed clear differentiation depending on stress. The PCA scores for the MSAP profiles clearly separated the genetic from the epigenetic structure, and also significantly separated the samples within each group in response to drought. Changes in DNA methylation highlight the large capacity of plants to rapidly acclimate to changing environmental conditions, including trees with long life spans, and our results demonstrate those changes. These changes, although unable to prevent the decreased growth and higher mortality associated with this experimental drought, occurred together with a dampening in such decreases as the long-term treatment progressed. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Time-domain separation of optical properties from structural transitions in resonantly bonded materials.

PubMed

Waldecker, Lutz; Miller, Timothy A; Rudé, Miquel; Bertoni, Roman; Osmond, Johann; Pruneri, Valerio; Simpson, Robert E; Ernstorfer, Ralph; Wall, Simon

2015-10-01

The extreme electro-optical contrast between crystalline and amorphous states in phase-change materials is routinely exploited in optical data storage and future applications include universal memories, flexible displays, reconfigurable optical circuits, and logic devices. Optical contrast is believed to arise owing to a change in crystallinity. Here we show that the connection between optical properties and structure can be broken. Using a combination of single-shot femtosecond electron diffraction and optical spectroscopy, we simultaneously follow the lattice dynamics and dielectric function in the phase-change material Ge2Sb2Te5 during an irreversible state transformation. The dielectric function changes by 30% within 100 fs owing to a rapid depletion of electrons from resonantly bonded states. This occurs without perturbing the crystallinity of the lattice, which heats with a 2-ps time constant. The optical changes are an order of magnitude larger than those achievable with silicon and present new routes to manipulate light on an ultrafast timescale without structural changes.

Changing Arctic ecosystems--research to understand and project changes in marine and terrestrial ecosystems of the Arctic

USGS Publications Warehouse

Geiselman, Joy; DeGange, Anthony R.; Oakley, Karen; Derksen, Dirk; Whalen, Mary

2012-01-01

Ecosystems and their wildlife communities are not static; they change and evolve over time due to numerous intrinsic and extrinsic factors. A period of rapid change is occurring in the Arctic for which our current understanding of potential ecosystem and wildlife responses is limited. Changes to the physical environment include warming temperatures, diminishing sea ice, increasing coastal erosion, deteriorating permafrost, and changing water regimes. These changes influence biological communities and the ways in which human communities interact with them. Through the new initiative Changing Arctic Ecosystems (CAE) the U.S. Geological Survey (USGS) strives to (1) understand the potential suite of wildlife population responses to these physical changes to inform key resource management decisions such as those related to the Endangered Species Act, and (2) provide unique insights into how Arctic ecosystems are responding under new stressors. Our studies examine how and why changes in the ice-dominated ecosystems of the Arctic are affecting wildlife and will provide a better foundation for understanding the degree and manner in which wildlife species respond and adapt to rapid environmental change. Changes to Arctic ecosystems will be felt broadly because the Arctic is a production zone for hundreds of species that migrate south for the winter. The CAE initiative includes three major research themes that span Arctic ice-dominated ecosystems and that are structured to identify and understand the linkages between physical processes, ecosystems, and wildlife populations. The USGS is applying knowledge-based modeling structures such as Bayesian Networks to integrate the work.

A Policy Paper on Applied Education.

ERIC Educational Resources Information Center

Murphy, Jerry

1992-01-01

Applied education, the integration of academic and vocational curricula, cannot supply the trained people needed by a rapidly changing society without sufficient planning and resources. Shortages of skilled workers are a societal issue requiring significant structural adjustment in the way skilled trades are managed. (JOW)

Mastering School Reform.

ERIC Educational Resources Information Center

Goens, George A.; Clover, Sharon I. R.

School organizations must become responsive and flexible to address rapidly changing social, economic, and demographic conditions. Reform attempts to date have not worked because they were layered on old structures and perceptions in a fragmented, piecemeal fashion. The fundamental transformation of education that is required demands a paradigm…

Solar wind and coronal structure near sunspot minimum - Pioneer and SMM observations from 1985-1987

NASA Technical Reports Server (NTRS)

Mihalov, J. D.; Barnes, A.; Hundhausen, A. J.; Smith, E. J.

1990-01-01

Changes in solar wind speed and magnetic polarity observed at the Pioneer spacecraft are discussed here in terms of the changing magnetic geometry implied by SMM coronagraph observations over the period 1985-1987. The pattern of recurrent solar wind streams, the long-term average speed, and the sector polarity of the interplanetary magnetic field all changed in a manner suggesting both a temporal variation, and a changing dependence on heliographic latitude. Coronal observations during this epoch show a systematic variation in coronal structure and the magnetic structure imposed on the expanding solar wind. These observations suggest interpretation of the solar wind speed variations in terms of the familiar model where the speed increases with distance from a nearly flat interplanetary current sheet, and where this current sheet becomes aligned with the solar equatorial plane as sunspot minimum approaches, but deviates rapidly from that orientation after minimum.

A review of rapid solidification studies of intermetallic compounds

NASA Technical Reports Server (NTRS)

Koch, C. C.

1985-01-01

A review of rapid solidification studies of high-temperature ordered intermetallic compounds is presented. Emphasis is on the nickel - and iron- aluminides which are of potential interest as structural materials. The nickel-base aluminides which have been rapidly solidified exhibit changes in grain size, compositional segregation, and degree of long range order (as reflected in APB size and distribution) which markedly affect mechanical properties. Some experiments indicate the formation of a metastable L1(2) phase in rapidly solidified Fe-(Ni,Mn)-Al-C alloys, while other work observes only a metastable fcc phase in the same composition range. The metastable phases and/or microstructures in both nickel and iron aluminides are destroyed by annealing at temperatures above 750 K, with subsequent degradation of mechanical properties. Rapid solidification studies of several other intermetallic compounds are briefly noted.

Animal responses to natural disturbance and climate extremes: a review

NASA Astrophysics Data System (ADS)

Sergio, Fabrizio; Blas, Julio; Hiraldo, Fernando

2018-02-01

Natural disturbances, such as droughts, fires or hurricanes, are key drivers of ecological heterogeneity and ecosystem function. The frequency and severity of these episodes is unequivocally expected to increase in the coming decades, through the concerted action of climate change and anthropogenic pressures. This will impose severe challenges for many biota through exposure to rapidly changing conditions never experienced in the preceding millennia. Thus, it is urgently needed to gain a thorough understanding of animal responses and adaptations to disturbances in order to better estimate potential future impacts. Here, we review such adjustments and find that animals may respond to disturbances through changes in: (1) behaviour, such as altered mobility, emigration, resource-switching, refuge use, suspended animation, or biotic interactions; (2) life history traits, such as survival, aging, longevity, recruitment, reproductive restraint, breeding output, phenology and bet-hedging tactics; (3) morphology, such as rapid evolution through size-dependent mortality or facultative metamorphosis; (4) physiology, such as altered body condition, pathogen prevalence and transmission, or adrenocortical modulation of stress responses to emergency conditions; (5) genetic structure, such as changes in frequency of polymorphic variants or diversity-modulation through mortality bottlenecks. Individual-level responses scale up to population and community responses, such as altered density, population dynamics, distribution, local extinction and colonization, or assemblage structure and diversity. Overall, disturbances have pervasive effects on individuals, populations and communities of vertebrates and invertebrates of all realms, biomes, continents and ecosystems. Their rapidly increasing incidence and severity will bring unique study opportunities for researchers and novel, unpredictable challenges for managers, while demanding tougher choices and more proactive crisis-preparation for conservationists, as well as mentality changes for all. Under all conditions, disturbances may soon become the defining signatures of most ecosystems and the dynamic leitmotif of modern ecology.

The impact of hospital structure and restructuring on the nursing workforce.

PubMed

Duffield, Christine; Kearin, Mark; Johnston, Judy; Leonard, Joanna

2007-01-01

Health systems throughout much of the world have been subject to 'reform' in recent years as countries have attempted to contain the rapidly rising costs of health care. Changes to hospital structures (restructuring) have been an important part of these reforms. A significant impact of current approaches to restructuring is the loss of, or changes to, nursing management roles and functions. Australian hospitals Little evaluation has been undertaken to determine the impact of hospital structure and organisational restructuring on the nursing workforce. There is some indication that nurses have experienced a loss of key management positions, which may impact on their capacity to ensure that adequate and safe care is provided at the ward level.

SIMS: A Hybrid Method for Rapid Conformational Analysis

PubMed Central

Gipson, Bryant; Moll, Mark; Kavraki, Lydia E.

2013-01-01

Proteins are at the root of many biological functions, often performing complex tasks as the result of large changes in their structure. Describing the exact details of these conformational changes, however, remains a central challenge for computational biology due the enormous computational requirements of the problem. This has engendered the development of a rich variety of useful methods designed to answer specific questions at different levels of spatial, temporal, and energetic resolution. These methods fall largely into two classes: physically accurate, but computationally demanding methods and fast, approximate methods. We introduce here a new hybrid modeling tool, the Structured Intuitive Move Selector (sims), designed to bridge the divide between these two classes, while allowing the benefits of both to be seamlessly integrated into a single framework. This is achieved by applying a modern motion planning algorithm, borrowed from the field of robotics, in tandem with a well-established protein modeling library. sims can combine precise energy calculations with approximate or specialized conformational sampling routines to produce rapid, yet accurate, analysis of the large-scale conformational variability of protein systems. Several key advancements are shown, including the abstract use of generically defined moves (conformational sampling methods) and an expansive probabilistic conformational exploration. We present three example problems that sims is applied to and demonstrate a rapid solution for each. These include the automatic determination of “active” residues for the hinge-based system Cyanovirin-N, exploring conformational changes involving long-range coordinated motion between non-sequential residues in Ribose-Binding Protein, and the rapid discovery of a transient conformational state of Maltose-Binding Protein, previously only determined by Molecular Dynamics. For all cases we provide energetic validations using well-established energy fields, demonstrating this framework as a fast and accurate tool for the analysis of a wide range of protein flexibility problems. PMID:23935893

Vertical distribution of bacterial community is associated with the degree of soil organic matter decomposition in the active layer of moist acidic tundra.

PubMed

Kim, Hye Min; Lee, Min Jin; Jung, Ji Young; Hwang, Chung Yeon; Kim, Mincheol; Ro, Hee-Myong; Chun, Jongsik; Lee, Yoo Kyung

2016-11-01

The increasing temperature in Arctic tundra deepens the active layer, which is the upper layer of permafrost soil that experiences repeated thawing and freezing. The increasing of soil temperature and the deepening of active layer seem to affect soil microbial communities. Therefore, information on soil microbial communities at various soil depths is essential to understand their potential responses to climate change in the active layer soil. We investigated the community structure of soil bacteria in the active layer from moist acidic tundra in Council, Alaska. We also interpreted their relationship with some relevant soil physicochemical characteristics along soil depth with a fine scale (5 cm depth interval). The bacterial community structure was found to change along soil depth. The relative abundances of Acidobacteria, Gammaproteobacteria, Planctomycetes, and candidate phylum WPS-2 rapidly decreased with soil depth, while those of Bacteroidetes, Chloroflexi, Gemmatimonadetes, and candidate AD3 rapidly increased. A structural shift was also found in the soil bacterial communities around 20 cm depth, where two organic (upper Oi and lower Oa) horizons are subdivided. The quality and the decomposition degree of organic matter might have influenced the bacterial community structure. Besides the organic matter quality, the vertical distribution of bacterial communities was also found to be related to soil pH and total phosphorus content. This study showed the vertical change of bacterial community in the active layer with a fine scale resolution and the possible influence of the quality of soil organic matter on shaping bacterial community structure.

Tropical fishes dominate temperate reef fish communities within western Japan.

PubMed

Nakamura, Yohei; Feary, David A; Kanda, Masaru; Yamaoka, Kosaku

2013-01-01

Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay); the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008-2010). This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E) the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores) shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable positive economic impacts to the local tourism industry and bring qualitative changes to both local and regional fisheries resources.

Tropical Fishes Dominate Temperate Reef Fish Communities within Western Japan

PubMed Central

Nakamura, Yohei; Feary, David A.; Kanda, Masaru; Yamaoka, Kosaku

2013-01-01

Climate change is resulting in rapid poleward shifts in the geographical distribution of tropical and subtropical fish species. We can expect that such range shifts are likely to be limited by species-specific resource requirements, with temperate rocky reefs potentially lacking a range of settlement substrates or specific dietary components important in structuring the settlement and success of tropical and subtropical fish species. We examined the importance of resource use in structuring the distribution patterns of range shifting tropical and subtropical fishes, comparing this with resident temperate fish species within western Japan (Tosa Bay); the abundance, diversity, size class, functional structure and latitudinal range of reef fishes utilizing both coral reef and adjacent rocky reef habitat were quantified over a 2 year period (2008–2010). This region has undergone rapid poleward expansion of reef-building corals in response to increasing coastal water temperatures, and forms one of the global hotspots for rapid coastal changes. Despite the temperate latitude surveyed (33°N, 133°E) the fish assemblage was both numerically, and in terms of richness, dominated by tropical fishes. Such tropical faunal dominance was apparent within both coral, and rocky reef habitats. The size structure of the assemblage suggested that a relatively large number of tropical species are overwintering within both coral and rocky habitats, with a subset of these species being potentially reproductively active. The relatively high abundance and richness of tropical species with obligate associations with live coral resources (i.e., obligate corallivores) shows that this region holds the most well developed temperate-located tropical fish fauna globally. We argue that future tropicalisation of the fish fauna in western Japan, associated with increasing coral habitat development and reported increasing shifts in coastal water temperatures, may have considerable positive economic impacts to the local tourism industry and bring qualitative changes to both local and regional fisheries resources. PMID:24312528

A global fingerprint of macro-scale changes in urban structure from 1999 to 2009

NASA Astrophysics Data System (ADS)

Frolking, Steve; Milliman, Tom; Seto, Karen C.; Friedl, Mark A.

2013-06-01

Urban population now exceeds rural population globally, and 60-80% of global energy consumption by households, businesses, transportation, and industry occurs in urban areas. There is growing evidence that built-up infrastructure contributes to carbon emissions inertia, and that investments in infrastructure today have delayed climate cost in the future. Although the United Nations statistics include data on urban population by country and select urban agglomerations, there are no empirical data on built-up infrastructure for a large sample of cities. Here we present the first study to examine changes in the structure of the world’s largest cities from 1999 to 2009. Combining data from two space-borne sensors—backscatter power (PR) from NASA’s SeaWinds microwave scatterometer, and nighttime lights (NL) from NOAA’s defense meteorological satellite program/operational linescan system (DMSP/OLS)—we report large increases in built-up infrastructure stock worldwide and show that cities are expanding both outward and upward. Our results reveal previously undocumented recent and rapid changes in urban areas worldwide that reflect pronounced shifts in the form and structure of cities. Increases in built-up infrastructure are highest in East Asian cities, with Chinese cities rapidly expanding their material infrastructure stock in both height and extent. In contrast, Indian cities are primarily building out and not increasing in verticality. This new dataset will help characterize the structure and form of cities, and ultimately improve our understanding of how cities affect regional-to-global energy use and greenhouse gas emissions.

Latinos and Education: A Critical Reader.

ERIC Educational Resources Information Center

Darder, Antonia, Ed.; And Others

Latinos are among the nation's most educationally disadvantaged and economically disenfranchised groups. Addressing this reality within the context of a rapidly changing economy and society, this book links educational practice and the structural dimensions that shape institutional life. Sections focus on the political economy of schooling,…

The New Paradox of the College Textbook.

ERIC Educational Resources Information Center

Lichtenberg, James

1992-01-01

As college textbooks have become more attractive, sophisticated, and useful, the textbook industry is suffering from high costs, increased popularity of used books, effects of rapidly advancing information and instructional technology, the atypical business structure of the college textbook market, and changing textbook development processes. (MSE)

Tipping Points in Resource Abundance Drive Irreversible Changes in Community Structure.

PubMed

Haney, Seth D; Siepielski, Adam M

2018-05-01

Global climate change has made what were seemingly extraordinary environmental conditions, such as prolonged droughts, commonplace. One consequence of extreme environmental change is concomitant changes in resource abundance. How will such extreme resource changes impact biodiversity? We developed a trait-based consumer-resource model to examine how resource abundance affects the potential for adaptive evolution and coexistence among competitors. We found that moderate changes in resource abundance have little effect on trait evolution. However, when resource scarcities were sufficiently extreme, a critical transition-a tipping point-occurred, which caused consumer traits to diverge and restructured the community in a way that outlasted the scarcity. Therefore, even though traits can evolve in response to minor resource fluctuations, large environmental shifts may be necessary for producing long-lasting impacts on community structure. These results may also help to illuminate patterns of stasis frequently observed in nature, despite the considerable evidence demonstrating rapid evolutionary change.

Structure and screening in molecular and metallic hydrogen at high pressure

NASA Technical Reports Server (NTRS)

Wood, D. M.; Ashcroft, N. W.

1981-01-01

A variational wavefunction is used to express the (spin restricted) Hartree-Fock energy as reciprocal lattice sums for static lattice FCC monatomic hydrogen and diatomic Pa3 molecular hydrogen. In the monatomic phase the hydrogenic orbital range closely parallels the inverse Thomas-Fermi wavevector; the corresponding energy E has a minimum of -0.929 Ryd/electron at r sub s = 1.67. For the diatomic phase E(r sub s) is similar, but the constituent energies, screening, and bond length reflect a qualitative change in the nature of the solid at r sub s = 2.8. This change is interpreted in terms of a transition from protons as structural units (at high density) to weakly interacting models (at low density). Insensitivity of the total energy to a rapid fall in the bond length suggests association with the rotational transition where the rapid molecular orientations characteristic of high pressures disappear and the molecules rotate freely at low pressure.

Western North Pacific Tropical Cyclone Formation and Structure Change in TCS-08

DTIC Science & Technology

2011-09-30

cyclones often transition to a fast-moving and rapidly- developing extratropical cyclone that may contain gale-, storm -, or hurricane-force winds... storm begins the process of extratropical transition have revealed the role of vertical wind shear in defining structural variations related to the...horizontal wind radii as the storm starts the process of extratropical transition. Elsberry et al. (2011) have extended the analysis of the

Random close packing of disks and spheres in confined geometries

NASA Astrophysics Data System (ADS)

Desmond, Kenneth W.; Weeks, Eric R.

2009-11-01

Studies of random close packing of spheres have advanced our knowledge about the structure of systems such as liquids, glasses, emulsions, granular media, and amorphous solids. In confined geometries, the structural properties of random-packed systems will change. To understand these changes, we study random close packing in finite-sized confined systems, in both two and three dimensions. Each packing consists of a 50-50 binary mixture with particle size ratio of 1.4. The presence of confining walls significantly lowers the overall maximum area fraction (or volume fraction in three dimensions). A simple model is presented, which quantifies the reduction in packing due to wall-induced structure. This wall-induced structure decays rapidly away from the wall, with characteristic length scales comparable to the small particle diameter.

Suppressed oxygen extraction and degradation of LiNi xMn yCo zO 2 cathodes at high charge cut-off voltages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jianming; Yan, Pengfei; Zhang, Jiandong

The capacity degradation mechanism in lithium nickel–manganese–cobalt oxide (NMC) cathodes (LiNi 1/3Mn 1/3Co 1/3O 2 (NMC 333) and LiNi 0.4Mn 0.4Co 0.2O 2 (NMC 442)) during high-voltage (cut-off of 4.8 V) operation has been investigated. In contrast to NMC 442, NMC 333 exhibits rapid structural changes including severe micro-crack formation and phase transformation from a layered to a disordered rock-salt structure, as well as interfacial degradation during high-voltage cycling, leading to a rapid increase of the electrode resistance and fast capacity decline. The fundamental reason behind the poor structural and interfacial stability of NMC 333 was found to be correlatedmore » to its high Co content and the significant overlap between the Co 3+/4+ t 2g and O 2- 2p bands, resulting in oxygen removal and consequent structural changes at high voltages. In addition, oxidation of the electrolyte solvents by the extracted oxygen species generates acidic species, which then attack the electrode surface and form highly resistive LiF. These findings highlight that both the structural and interfacial stability should be taken into account when tailoring cathode materials for high voltage battery systems.« less

Suppressed oxygen extraction and degradation of LiNixMnyCozO2 cathodes at high charge cut-off voltages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jianming; Yan, Pengfei; Zhang, Jiandong

The capacity degradation mechanism in lithium nickel-manganese-cobalt oxide (NMC) cathodes (LiNi1/3Mn1/3Co1/3O2 (NMC333) and LiNi0.4Mn0.4Co0.2O2 (NMC442)) during high-voltage (cut-off of 4.8 V) operation has been investigated. In contrast to NMC442, NMC333 exhibits rapid structural changes including severe micro-crack formation and phase transformation from a layered to a disordered rock-salt structure, as well as interfacial degradation during high-voltage cycling, leading to a rapid increase of the electrode resistance and fast capacity decline. The fundamental reason behind the poor structural and interfacial stability of NMC333 was found to be correlated to its high Co content and the significant overlap between the Co3+/4+ t(2g)more » and O2- 2p bands, resulting in oxygen removal and consequent structural changes at high voltages. In addition, oxidation of the electrolyte solvents by the extracted oxygen species generates acidic species, which then attack the electrode surface and form highly resistive LiF. These findings highlight that both the structural and interfacial stability should be taken into account when tailoring cathode materials for high voltage battery systems« less

The Dubai Community Psychiatric Survey: II. Development of the Socio-cultural Change Questionnaire.

PubMed

Bebbington, P; Ghubash, R; Hamdi, E

1993-04-01

The Dubai Community Psychiatric Survey was carried out to assess the effect of very rapid social change on the mental health of women in Dubai, one of the United Arab Emirates. In order to measure social change at an individual level, we developed a questionnaire covering behaviour and attitudes in a wide range of situations, the Socio-cultural Change Questionnaire (ScCQ). In this paper we give an account of the considerations that determined the form of the ScCQ, its structural characteristics, and its validity.

Digital Microdroplet Ejection Technology-Based Heterogeneous Objects Prototyping

PubMed Central

Yang, Jiquan; Feng, Chunmei; Yang, Jianfei; Zhu, Liya; Guo, Aiqing

2016-01-01

An integrate fabrication framework is presented to build heterogeneous objects (HEO) using digital microdroplets injecting technology and rapid prototyping. The heterogeneous materials part design and manufacturing method in structure and material was used to change the traditional process. The net node method was used for digital modeling that can configure multimaterials in time. The relationship of material, color, and jetting nozzle was built. The main important contributions are to combine the structure, material, and visualization in one process and give the digital model for manufacture. From the given model, it is concluded that the method is effective for HEO. Using microdroplet rapid prototyping and the model given in the paper HEO could be gotten basically. The model could be used in 3D biomanufacturing. PMID:26981110

Transition to high rate aerospace NDI processes

NASA Astrophysics Data System (ADS)

Vanderheiden, Bert; Thomson, Clint; Ivakhnenko, Igor; Garner, Chuck

2018-04-01

With the rapidly expanding use of carbon fiber composite materials in military and commercial aircraft, processes to manufacture and inspect the structural components must evolve to ensure economic viability. Inspection techniques which were developed to inspect products produced at a rate of one or two structures a month are not fast or flexible enough to inspect more than 8500 parts per month. This presentation describes the evolution of phased array ultrasonic inspection systems to provide the increased rate capacity, the flexibility to accommodate multiple unique designs, and the ability to rapidly adjust to product design changes. The paper will describe how system developments were made in response to new programs resulting in a much less expensive, higher degree of accuracy, increased flexibility, and lower cycle time inspections.

Digital Microdroplet Ejection Technology-Based Heterogeneous Objects Prototyping.

PubMed

Li, Na; Yang, Jiquan; Feng, Chunmei; Yang, Jianfei; Zhu, Liya; Guo, Aiqing

2016-01-01

An integrate fabrication framework is presented to build heterogeneous objects (HEO) using digital microdroplets injecting technology and rapid prototyping. The heterogeneous materials part design and manufacturing method in structure and material was used to change the traditional process. The net node method was used for digital modeling that can configure multimaterials in time. The relationship of material, color, and jetting nozzle was built. The main important contributions are to combine the structure, material, and visualization in one process and give the digital model for manufacture. From the given model, it is concluded that the method is effective for HEO. Using microdroplet rapid prototyping and the model given in the paper HEO could be gotten basically. The model could be used in 3D biomanufacturing.

Southern Great Plains Rapid Ecoregional Assessment: pre-assessment report

USGS Publications Warehouse

Assal, Timothy J.; Melcher, Cynthia P.; Carr, Natasha B.

2015-01-01

An overview on the ecology and management issues for each Conservation Element is provided, including distribution and ecology, landscape structure and dynamics, and associated species of management concern affiliated with each Conservation Element. For each Conservation Element, effects of the Change Agents are described. An overview of potential key ecological attributes and potential Change Agents are summarized by conceptual models and tables. The tables provide an organizational framework and background information for evaluating the key ecological attributes and Change Agents in Phase II.

Rapid water quality change in the Elwha River estuary complex during dam removal

USGS Publications Warehouse

Foley, Melissa M.; Duda, Jeffrey J.; Beirne, Matthew M.; Paradis, Rebecca; Ritchie, Andrew; Warrick, Jonathan A.

2015-01-01

Dam removal in the United States is increasing as a result of structural concerns, sedimentation of reservoirs, and declining riverine ecosystem conditions. The removal of the 32 m Elwha and 64 m Glines Canyon dams from the Elwha River in Washington, U.S.A., was the largest dam removal project in North American history. During the 3 yr of dam removal—from September 2011 to August 2014—more than ten million cubic meters of sediment was eroded from the former reservoirs, transported downstream, and deposited throughout the lower river, river delta, and nearshore waters of the Strait of Juan de Fuca. Water quality data collected in the estuary complex at the mouth of the Elwha River document how conditions in the estuary changed as a result of sediment deposition over the 3 yr the dams were removed. Rapid and large-scale changes in estuary conditions—including salinity, depth, and turbidity—occurred 1 yr into the dam removal process. Tidal propagation into the estuary ceased following a large sediment deposition event that began in October 2013, resulting in decreased salinity, and increased depth and turbidity in the estuary complex. These changes have persisted in the system through dam removal, significantly altering the structure and functioning of the Elwha River estuary ecosystem.

Reading skill and structural brain development

PubMed Central

Houston, S.M.; Lebel, C.; Katzir, T.; Manis, F.R.; Kan, E.; Rodriguez, G.R.; Sowell, E.R.

2014-01-01

Reading is a learned skill that is likely influenced by both brain maturation and experience. Functional imaging studies have identified brain regions important for skilled reading, but the structural brain changes that co-occur with reading acquisition remain largely unknown. We investigated maturational volume changes in brain reading regions and their association with performance on reading measures. Sixteen typically developing children (5-15 years old, 8 male, mean age of sample=10.06 ±3.29) received two magnetic resonance imaging (MRI) scans, (mean inter-scan interval =2.19 years), and were administered a battery of cognitive measures. Volume changes between time points in five bilateral cortical regions of interest were measured, and assessed for relationships to three measures of reading. Better baseline performances on measures of word reading, fluency and rapid naming, independent of age and total cortical gray matter volume change, were associated with volume decrease in the left inferior parietal cortex. Better baseline performance on a rapid naming measure was associated with volume decrease in the left inferior frontal region. These results suggest that children who are better readers, and who perhaps read more than less skilled readers, exhibit different development trajectories in brain reading regions. Understanding relationships between reading performance, reading experience and brain maturation trajectories may help with the development and evaluation of targeted interventions. PMID:24407200

Rise time and formant transition duration in the discrimination of speech sounds: the Ba-Wa distinction in developmental dyslexia.

PubMed

Goswami, Usha; Fosker, Tim; Huss, Martina; Mead, Natasha; Szucs, Dénes

2011-01-01

Across languages, children with developmental dyslexia have a specific difficulty with the neural representation of the sound structure (phonological structure) of speech. One likely cause of their difficulties with phonology is a perceptual difficulty in auditory temporal processing (Tallal, 1980). Tallal (1980) proposed that basic auditory processing of brief, rapidly successive acoustic changes is compromised in dyslexia, thereby affecting phonetic discrimination (e.g. discriminating /b/ from /d/) via impaired discrimination of formant transitions (rapid acoustic changes in frequency and intensity). However, an alternative auditory temporal hypothesis is that the basic auditory processing of the slower amplitude modulation cues in speech is compromised (Goswami et al., 2002). Here, we contrast children's perception of a synthetic speech contrast (ba/wa) when it is based on the speed of the rate of change of frequency information (formant transition duration) versus the speed of the rate of change of amplitude modulation (rise time). We show that children with dyslexia have excellent phonetic discrimination based on formant transition duration, but poor phonetic discrimination based on envelope cues. The results explain why phonetic discrimination may be allophonic in developmental dyslexia (Serniclaes et al., 2004), and suggest new avenues for the remediation of developmental dyslexia. © 2010 Blackwell Publishing Ltd.

RELATIONSHIP OF MICROBIAL COMMUNITY STRUCTURE AND CARBON DYNAMICS IN SOILS FROM BRAZILIAN SAVANNAS

EPA Science Inventory

Fertilization is a widespread management practice in savanna areas of central Brazil (Cerrado) that are undergoing rapid agricultural land use changes. We conducted field and laboratory studies in soils with added fertilizers to determine the effect that fertilization of native a...

Postimplementation Planning and Organizational Structure of Enterprise Resource Planning Systems

ERIC Educational Resources Information Center

Wilson, Charmaine V.

2012-01-01

Globalization, rapid technological changes, and competitive pressures have resulted in company leaders' worldwide adopting of enterprise resource planning (ERP) systems to improve productivity and business operations and reduce costs in the post-implementation phase. The research addressed organizational leaders' inability to optimize…

Western Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

USDA-ARS?s Scientific Manuscript database

The rapid expansion of western juniper into neighboring plant communities during the past 130 years has been linked to increased soil erosion; reduced forage production; altered wildlife habitat; changes in plant community composition, structure, and biodiversity. Impacts of post-settlement woodland...

Motivational Orientations in Work

ERIC Educational Resources Information Center

Murtonen, Mari; Olkinuora, Erkki; Palonen, Tuire; Hakkarainen, Kai; Lehtinen, Erno

2008-01-01

The rapid development in working life during recent decades has changed the structures of work organisations and expectations of employees' work. Differing forms of professional employment and different types of organisational environments likely promote different types of motivational patterns in workers. The aim of this study was to apply a…

Microbial Community Response to Warming and Correlations to Organic Carbon Degradation in an Arctic Tundra Soil

NASA Astrophysics Data System (ADS)

Yang, Z.; Yang, S.; Zhou, J.; Wullschleger, S. D.; Graham, D. E.; Yang, Y.; Gu, B.

2016-12-01

Climate warming increases microbial activity and thus decomposition of soil organic carbon (SOC) stored in Arctic tundra, but changes in microbial community and its correlations to SOC decomposition are poorly understood. Using a microbial functional gene array (GeoChip 5.0), we examined the microbial functional community structure changes with temperature (-2 and +8 °C) in an anoxic incubation experiment with a high-centered polygon trough soil from Barrow, Alaska. Through a 122-day incubation, we show that functional community structure was significantly altered (P < 0.05) by 8 °C warming, with functional diversity decreasing in response to warming and rapid degradation of the labile soil organic substrates. In contrast, microbial community structure was largely unchanged by -2 °C incubation. In the organic layer soil, gene abundances associated with fermentation, methanogenesis, and iron reduction all decreased significantly (P < 0.05) following the incubation at 8 °C. These observations corroborate strongly with decreased methane and reducing sugar production rates and iron reduction during the incubation. These results demonstrate a rapid and sensitive microbial response to increasing soil temperature, and suggest important roles of microbial communities in moderating SOC degradation and iron cycling in warming Arctic tundra.

Cytoplasmic inheritance of parent-offspring cell structure in the clonal diatom Cyclotella meneghiniana.

PubMed

Shirokawa, Yuka; Shimada, Masakazu

2016-11-16

In cytoplasmic inheritance, structural states of a parent cell could be transmitted to offspring cells via two mechanisms. The first is referred to as the hangover of parent structure, where the structure itself remains and faithfully transmits within offspring cells; the second is structural inheritance, wherein the parent structure functions as a template for development of new offspring structure. We estimated to what extent the parent structure affects the development of offspring structure by structural inheritance, using a clone of the diatom Cyclotella meneghiniana The cell has two siliceous valves (a cell wall part at both cell poles): one is inherited from the parent and the other is newly formed. We estimated cytoplasmic heritability by comparing valve traits (central fultoportulae (CTFP), striae, central area, and cell diameter) of parent and new offspring valves, using single-cell isolation and valve labelling. Parent-offspring valve trait regressions showed that all traits, except CTFP, were significantly correlated. We formulated a quantitative genetic model considering the diatom inheritance system and revealed short-term rapid evolution compared with other inheritance systems. Diatom structural inheritance will have evolved to enable clonal populations to rapidly acquire and maintain suitable structures for temporal changes in environments and life-cycle stages. © 2016 The Author(s).

Process dependency of radiation hardness of rapid thermal reoxidized nitrided gate oxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weishin Lu; Kuanchin Lin; Jenngwo Hwu

The radiation hardness of MOS capacitors with various reoxidized nitrided oxide (RNO) structures is studied by changing the durations of rapid thermal processes during sample preparation and by applying irradiation-then-anneal (ITA) treatments on samples after preparation. It is found that the initial flatband voltage and midgap interface trap density of MOS capacitors exhibit turnaround'' dependency on the total time of nitridation and reoxidation processes. For samples with nitrided oxide (NO) structures, the radiation-induced variations of above parameters are also turnaround''-dependent on nitridation time. However, when the reoxidation process is performed, the radiation hardness for all samples will be gradually improvedmore » with increasing reoxidation time no matter what the nitridation time is. The most radiation-hard process for RNO structures is suggested. Finally, it is found that when ITA treatments are applied on samples after preparation, their radiation hardness is much improved.« less

Research of Energy Substitution Strategy of China

NASA Astrophysics Data System (ADS)

Zhang, Lifeng; kai, Chen

For a long time, China's energy endowment structure determines the production structure and consumption structure of energy are coal-based.This situation is difficult to change for quite a long time. With the rapid economic growth, industrialization and urbanization, the demand for energy, especially for oil, natural gas will continue to increase. But the oil and gas supply can not meet the needs of rapid growth. The most direct way is to import, and imports will be charged by the international energy situation, and will affect energy and economic security. In view of our country abundant coal resources, we can consider to use coal substituting oil and natural gas to reduce dependence on foreign energy, to strengthen energy and economic security. Therefore, using translog production function, the text forecasts substitution elasticity and the marginal substitution rate between the capital, coal, oil and natural gas, and puts forward substitution program.

Rapid Shifts in Soil and Forest Floor Microbial Communities with Changes in Vegetation during Secondary Tropical Forest Succession

NASA Astrophysics Data System (ADS)

Smith, A.; Marin-Spiotta, E.; Balser, T. C.

2012-12-01

Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. In order to predict how disturbance affects belowground carbon storage, it is important to understand how the forest floor and soil microbial community respond to changes in land cover, and the consequences on SOM formation and stabilization. We are measuring microbial functional diversity and activity across a long-term successional chronosequence of secondary forests regrowing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Here we report intra- and interannual data on soil and litter microbial community composition (via phospholipid fatty acid analysis, PLFA) and microbial activity (via extracellular enzyme activity) from active pastures, secondary forests aged 20, 30, 40, 70, and 90-years, and primary forests. Microbial community composition and extracellular enzyme activity differed significantly by season in these wet subtropical ecosystems, even though differences in mean monthly precipitation between the middle of the dry season (January) and the wet season (July) is only 30mm. Despite seasonal differences, there was a persistent strong effect of land cover type and forest successional stage, or age, on overall microbial community PLFA structure. Using principal component analysis, we found differences in microbial community structure among active pastures, early, and late successional forests. The separation of soil microbes into early and late successional communities parallels the clustering of tree composition data. While the successional patterns held across seasons, the importance of different microbial groups driving these patterns differed seasonally. Biomarkers for gram-positive and actinobacteria (i15:0 and 16:0 10Me) were associated with early (20, 30 & 40 year old) secondary forests in the dry season. These younger forest communities were identified by the biomarker for anaerobic gram-negative bacteria (c19:0) in the wet season, which suggests the presence of anaerobic microsites in these very clayey Oxisols. Enzymatic activity did not differ with succession but was highest in the dry season. We expect this may be due to decreased turnover of enzymes with low soil moisture. Interannual sampling has revealed a very rapid microbial response to changes in aboveground cover. Within a year following woody biomass encroachment, we detected a shift in the soil microbial community from a pasture-associated community to an early secondary forest community in one of our replicate pasture sites. This very rapid response in the belowground microbial community structure to changes in vegetation has not been strongly documented in the literature. This data supports a direct link between aboveground and belowground biotic community structures and highlights the importance of long-term repeated sampling of microbial communities in dynamic ecosystems. Our findings have implications for predicting rapid ecological responses to land-cover change.

Light activation of the LOV protein vivid generates a rapidly exchanging dimer.

PubMed

Zoltowski, Brian D; Crane, Brian R

2008-07-08

The fungal photoreceptor Vivid (VVD) plays an important role in the adaptation of blue-light responses in Neurospora crassa. VVD, an FAD-binding LOV (light, oxygen, voltage) protein, couples light-induced cysteinyl adduct formation at the flavin ring to conformational changes in the N-terminal cap (Ncap) of the VVD PAS domain. Size-exclusion chromatography (SEC), equilibrium ultracentrifugation, and static and dynamic light scattering show that these conformational changes generate a rapidly exchanging VVD dimer, with an expanded hydrodynamic radius. A three-residue N-terminal beta-turn that assumes two different conformations in a crystal structure of a VVD C71V variant is essential for light-state dimerization. Residue substitutions at a critical hinge between the Ncap and PAS core can inhibit or enhance dimerization, whereas a Tyr to Trp substitution at the Ncap-PAS interface stabilizes the light-state dimer. Cross-linking through engineered disulfides indicates that the light-state dimer differs considerably from the dark-state dimer found in VVD crystal structures. These results verify the role of Ncap conformational changes in gating the photic response of N. crassa and indicate that LOV-LOV homo- or heterodimerization may be a mechanism for regulating light-activated gene expression.

Global Competitives: Economic Imperatives for School Reform.

ERIC Educational Resources Information Center

Negroni, Peter J.

This paper describes the need for systemic educational reform in view of the gap between students who are adequately prepared for tomorrow's jobs and the needs of business/industry. Rapid changes in the workplace--fueled by technological advances, altered family structures, expectations of varied and higher performance skills, and an increase of…

If Not I.Q. - What?

ERIC Educational Resources Information Center

Tyler, Ralph W.

The use of psychological and educational tests in World War I led to their adoption in schools for testing intelligence and achievement in order to classify students academically according to a national norm. After World War II, rapid changes in occupational and social structure demanded the education and identification of students for employment.…

Teaching Old Dogs New Tricks: On the Continuing Education of Teachers.

ERIC Educational Resources Information Center

Bates, Richard

The emergence of globalization and its impact on knowledge, communications, economies, social structures, and institutions such as education is rapidly changing the context, content, and methods of teachers' work. Consequently, the continuing professional development of teachers, especially in Australia with its aging teacher force, is essential.…

Psychology in an Age of Ecological Crisis: From Personal Angst to Collective Action

ERIC Educational Resources Information Center

Stokols, Daniel; Misra, Shalini; Runnerstrom, Miryha Gould; Hipp, J. Aaron

2009-01-01

Recent technological, geophysical, and societal forces have fundamentally altered the structure and functioning of human environments. Prominent among these forces are the rise of the Internet; rapid rates of global environmental change; and widening rifts among different socioeconomic, racial, religious, and ethnic groups. The present article…

Re-Imagining Education Journalism

ERIC Educational Resources Information Center

West, Darrell M.; Whitehurst, Grover J.; Dionne, E.J., Jr.

2010-01-01

Education journalism is going through a gut-wrenching transformation of its business model and its organizational structure, even as the ways in which news is delivered are changing rapidly. Old business models have collapsed, and new ones are struggling to find their footing. Digital technologies have fundamentally altered the way news is…

Vascular structure determines pulmonary blood flow distribution

NASA Technical Reports Server (NTRS)

Hlastala, M. P.; Glenny, R. W.

1999-01-01

Scientific knowledge develops through the evolution of new concepts. This process is usually driven by new methodologies that provide observations not previously available. Understanding of pulmonary blood flow determinants advanced significantly in the 1960s and is now changing rapidly again, because of increased spatial resolution of regional pulmonary blood flow measurements.

Geographic patterns of genetic variation and population structure in Pinus aristata, Rocky Mountain bristlecone pine

USDA-ARS?s Scientific Manuscript database

Pinus aristata Engelm., Rocky Mountain bristlecone pine, has a narrow core geographic and elevational distribution, occurs in disjunct populations and is threatened by multiple stresses, including rapid climate change, white pine blister rust, and bark beetles. Knowledge of genetic diversity and pop...

NO REDUCTION IN GENETIC DIVERSITY DESPITE RAPID ADAPTATION TO PCB POLLUTION: IMPLICATIONS FOR CONSERVATION OF LARGE ESTUARINE POPULATIONS

EPA Science Inventory

Anthropogenic stressors can have negative fitness impacts on populations by reducing population size through direct mortality or reduced reproduction. Evolutionary consequences of pollutants are inevitable if genetic diversity and structure is changed as a result of these impact...

NO REDUCTION IN GENETIC DIVERSITY DESPITE RAPID ADAPTATION IN PCB POLLUTION: IMPLICATIONS FOR CONSERVATION OF LARGE ESTUARINE POPULATIONS

EPA Science Inventory

Anthropogenic stressors can have negative fitness impacts on populations by reducing population size through direct mortality or reduced reproduction. Evolutionary consequences of pollutants are inevitable if genetic diversity and structure are changed as a result of these impac...

Dislocated Workers and Midcareer Retraining in Other Industrial Nations.

ERIC Educational Resources Information Center

Bendick, Marc, Jr.

Market-oriented industrial nations other than the United States have experienced rapid structural changes in their economies and reemployment problems among dislocated midcareer workers. The Swedish active labor market approach is a socialized one. This system has been criticized for excessive reliance on microeconomic labor market programs to…

Temperature dependent Raman spectroscopy of melamine and structural analogs in milk powder

USDA-ARS?s Scientific Manuscript database

Hyperspectral Raman imaging has the potential for rapid screening of solid-phase samples for potential adulterants. We found that the Raman spectra of melamine analogs changed dramatically and uniquely as a function of elevated temperature. Raman spectra were acquired for urea, biuret, cyanuric acid...

Bacterial structures and ecosystem functions in glaciated floodplains: contemporary states and potential future shifts

PubMed Central

Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart EG; Robinson, Christopher T

2013-01-01

Glaciated alpine floodplains are responding quickly to climate change through shrinking ice masses. Given the expected future changes in their physicochemical environment, we anticipated variable shifts in structure and ecosystem functioning of hyporheic microbial communities in proglacial alpine streams, depending on present community characteristics and landscape structures. We examined microbial structure and functioning during different hydrologic periods in glacial (kryal) streams and, as contrasting systems, groundwater-fed (krenal) streams. Three catchments were chosen to cover an array of landscape features, including interconnected lakes, differences in local geology and degree of deglaciation. Community structure was assessed by automated ribosomal intergenic spacer analysis and microbial function by potential enzyme activities. We found each catchment to contain a distinct bacterial community structure and different degrees of separation in structure and functioning that were linked to the physicochemical properties of the waters within each catchment. Bacterial communities showed high functional plasticity, although achieved by different strategies in each system. Typical kryal communities showed a strong linkage of structure and function that indicated a major prevalence of specialists, whereas krenal sediments were dominated by generalists. With the rapid retreat of glaciers and therefore altered ecohydrological characteristics, lotic microbial structure and functioning are likely to change substantially in proglacial floodplains in the future. The trajectory of these changes will vary depending on contemporary bacterial community characteristics and landscape structures that ultimately determine the sustainability of ecosystem functioning. PMID:23842653

Bacterial structures and ecosystem functions in glaciated floodplains: contemporary states and potential future shifts.

PubMed

Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart E G; Robinson, Christopher T

2013-12-01

Glaciated alpine floodplains are responding quickly to climate change through shrinking ice masses. Given the expected future changes in their physicochemical environment, we anticipated variable shifts in structure and ecosystem functioning of hyporheic microbial communities in proglacial alpine streams, depending on present community characteristics and landscape structures. We examined microbial structure and functioning during different hydrologic periods in glacial (kryal) streams and, as contrasting systems, groundwater-fed (krenal) streams. Three catchments were chosen to cover an array of landscape features, including interconnected lakes, differences in local geology and degree of deglaciation. Community structure was assessed by automated ribosomal intergenic spacer analysis and microbial function by potential enzyme activities. We found each catchment to contain a distinct bacterial community structure and different degrees of separation in structure and functioning that were linked to the physicochemical properties of the waters within each catchment. Bacterial communities showed high functional plasticity, although achieved by different strategies in each system. Typical kryal communities showed a strong linkage of structure and function that indicated a major prevalence of specialists, whereas krenal sediments were dominated by generalists. With the rapid retreat of glaciers and therefore altered ecohydrological characteristics, lotic microbial structure and functioning are likely to change substantially in proglacial floodplains in the future. The trajectory of these changes will vary depending on contemporary bacterial community characteristics and landscape structures that ultimately determine the sustainability of ecosystem functioning.

Functional correlates of central white matter maturation in perinatal period in rabbits.

PubMed

Drobyshevsky, Alexander; Jiang, Rugang; Derrick, Matthew; Luo, Kehuan; Tan, Sidhartha

2014-11-01

Anisotropy indices derived from diffusion tensor imaging (DTI) are being increasingly used as biomarkers of central WM structural maturation, myelination and even functional development. Our hypothesis was that the rate of functional changes in central WM tracts directly reflects rate of changes in structural development as determined by DTI indices. We examined structural and functional development of four major central WM tracts with different maturational trajectories, including internal capsule (IC), corpus callosum (CC), fimbria hippocampi (FH) and anterior commissure (AC). Rabbits were chosen due to perinatal brain development being similar to humans, and four time points were studied: P1, P11, P18 and adults. Imaging parameters of structural maturation included fractional anisotropy (FA), mean and directional diffusivities derived from DTI, and T2 relaxation time. Axonal composition and degree of myelination were confirmed on electron microscopy. To assess functional maturation, conduction velocity was measured in myelinated and non-myelinated fibers by electrophysiological recordings of compound action potential in perfused brain slices. Diffusion indices and T2 relaxation time in rabbits followed a sigmoid curve during development similar to that for humans, with active changes even at premyelination stage. The shape of the developmental curve was different between the fiber tracts, with later onset but steeper rapid phase of development in IC and FH than in CC. The structural development was not directly related to myelination or to functional development. Functional properties in projection (IC) and limbic tracts (FH) matured earlier than in associative and commissural tracts (CC and AC). The rapid phase of changes in diffusion anisotropy and T2 relaxation time coincided with the development of functional responses and myelination in IC and FH between the second and third weeks of postnatal development in rabbits. In these two tracts, MRI indices could serve as surrogate markers of the early stage of myelination. However, the discordance between developmental change of diffusion indices, myelination and functional properties in CC and AC cautions against equating DTI index changes as biomarkers for myelination in all tracts. Copyright © 2014 Elsevier Inc. All rights reserved.

Spaceflight-induced Bone Loss: Is there a Risk for Accelerated Osteoporosis after Return?

NASA Technical Reports Server (NTRS)

Sibonga, Jean

2008-01-01

The evidence-to to-date suggests that the rapid rate of site-specific bone loss in space, due to the unbalanced stimulation of bone resorption, may predispose crew members to irreversible changes in bone structure and microarchitecture. No analyses conducted in the postflight period to assess microarchitectural changes. There is no complete analysis of skeletal recovery in the postflight period to evaluate the structural changes that accompany increases in DXA aBMD. Postflight analyses based upon QCT scans performed on limited crew members indicate reductions in hip bone strength and incomplete recovery at 1 year. No recovery of trabecular vBMD after 1 year return (HRP IWG). Time course of bone loss in space unknown.

Histone H4 hyperacetylation and rapid turnover of its acetyl groups in transcriptionally inactive rooster testis spermatids.

PubMed Central

Oliva, R; Mezquita, C

1982-01-01

In order to study the relationship between acetylation of histones, chromatin structure and gene activity, the distribution and turnover of acetyl groups among nucleosomal core histones and the extent of histone H4 acetylation were examined in rooster testis cell nuclei at different stages of spermatogenesis. Histone H4 was the predominant acetylated histone in mature testes. Hyperacetylation of H4 and rapid turnover of its acetyl groups are not univocally correlated with transcriptional activity since they were detected in both genetically active testicular cells and genetically inactive elongated spermatids. During the transition from nucleohistone to nucleoprotamine in elongated spermatids the chromatin undergoes dramatic structural changes with exposition of binding sites on DNA (1). Hyperacetylation of H4 and rapid turnover of its acetyl groups could be correlated with the particular conformation of chromatin in elongated spermatids and might represent a necessary condition for binding of chromosomal proteins to DNA. Images PMID:7162988

Market returns? Gender and theories of change in employment relations.

PubMed

Irwin, S; Bottero, W

2000-06-01

This paper explores recent arguments about the marketization of female labour, in the context of a wider analysis of the role of concepts like 'the market' and 'individualization' in sociological accounts of change in employment relations. It will be argued that within sociology there has been a tendency for rapid, large-scale changes in employment relations to be characterized as the breakdown of social influences or structures and as the emergence of atomized, individuated market forces. In the most recent models, change in the nature of gendered positions within employment are presented in terms of a decline of social structuring and social constraint. These emergent accounts hold similarities to classical economics, and to Marx's and Weber's accounts of employment, which also characterized new forms of employment relations in terms of the emptying of their social content and their replacement by market forms. We offer an alternative, moral economy, perspective which foregrounds the continued significance of social relations in the structuring of employment and employment change. We develop the argument through an analysis of gendered patterns of employment and change in family form.

Plates and Mantle Convection: A Far-From Equilibrium Self-Organized System

NASA Astrophysics Data System (ADS)

King, S. D.; Lowman, J. P.; Gable, C. W.

2001-12-01

A common observation of plate tectonics is that plate velocities change over short time scales. Some have speculated that these reorganization events are triggered by evolving plate boundaries. This work presents an alternative mechanism, due to the interaction of mobil plates and internally heated convection. We present numerical models of 3D Cartesian convection in an internally-heated fluid with mobile plates that exhibit rapid changes in plate motion. A persistent feature of these calculations is that plate motion is relatively uniform punctuated by rapid reorganization events where plate speed and direction change over a short time period. The rapid changes in plate motion result solely from the interaction of internally-heated convection and the mobile plates. Without plates, the convective planform of an internally-heated fluid evolves into a pattern with a larger number of small cells. When plates are included, the fluid is dominated by plate-scale structures; however, isolated regions develop where heat builds up. These isolated regions are near the location of mature slabs where the plates are older and thicker. As the system evolves, the temperature (and buoyancy) in these isolated regions increases, they become unstable and, as they rise, the net force on the plate is no longer dominated by `slab pull' from the mature slab. The plate reorganization allows the system to transfer heat from the short-wavelength, internal-heating scale, to the longer-wavelength, plate-cooling scale. As we will demonstrate, the interaction between plate motions and the mantle is sufficiently dynamic that evolving plate boundaries are not necessary to achieve rapid changes in plate motion.

Impact of an extreme climatic event on community assembly.

PubMed

Thibault, Katherine M; Brown, James H

2008-03-04

Extreme climatic events are predicted to increase in frequency and magnitude, but their ecological impacts are poorly understood. Such events are large, infrequent, stochastic perturbations that can change the outcome of entrained ecological processes. Here we show how an extreme flood event affected a desert rodent community that has been monitored for 30 years. The flood (i) caused catastrophic, species-specific mortality; (ii) eliminated the incumbency advantage of previously dominant species; (iii) reset long-term population and community trends; (iv) interacted with competitive and metapopulation dynamics; and (v) resulted in rapid, wholesale reorganization of the community. This and a previous extreme rainfall event were punctuational perturbations-they caused large, rapid population- and community-level changes that were superimposed on a background of more gradual trends driven by climate and vegetation change. Captured by chance through long-term monitoring, the impacts of such large, infrequent events provide unique insights into the processes that structure ecological communities.

Rapid and reversible photoinduced switching of a rotaxane crystal

NASA Astrophysics Data System (ADS)

Chen, Kai-Jen; Tsai, Ya-Ching; Suzaki, Yuji; Osakada, Kohtaro; Miura, Atsushi; Horie, Masaki

2016-11-01

Crystalline phase transitions caused by external stimuli have been used to detect physical changes in the solid-state properties. This study presents the mechanical switching of crystals of ferrocene-containing rotaxane controlled by focused laser light. The expansion and contraction of the crystals can be driven by turning on and off laser light at 445 nm. The irradiation-induced expansion of the crystal involves elongation along the a, b and c axes at 30 °C, whereas heating of the crystal at 105 °C causes the shortening of c axis. The expansions reversibly occur and have the advantage of a rapid relaxation (reverse) process. Single-crystal X-ray crystallography reveals the detailed structural changes of the molecules, corresponding to a change in the size of the crystals on laser irradiation. This molecular crystal behaviour induced by laser irradiation, is demonstrated for the remote control of objects, namely, microparticle transport and microswitching in an electric circuit.

Atomic and electronic structure transformations of silver nanoparticles under rapid cooling conditions.

PubMed

Lobato, I; Rojas, J; Landauro, C V; Torres, J

2009-02-04

The structural evolution and dynamics of silver nanodrops Ag(2869) (4.4 nm in diameter) under rapid cooling conditions have been studied by means of molecular dynamics simulations and electronic density of state calculations. The interaction of silver atoms is modelled by a tight-binding semiempirical interatomic potential proposed by Cleri and Rosato. The pair correlation functions and the pair analysis technique are used to reveal the structural transition in the process of solidification. It is shown that Ag nanoparticles evolve into different nanostructures under different cooling processes. At a cooling rate of 1.5625 × 10(13) K s(-1) the nanoparticles preserve an amorphous-like structure containing a large amount of 1551 and 1541 pairs which correspond to icosahedral symmetry. For a lower cooling rate (1.5625 × 10(12) K s(-1)), the nanoparticles transform into a crystal-like structure consisting mainly of 1421 and 1422 pairs which correspond to the face centred cubic and hexagonal close packed structures, respectively. The variations of the electronic density of states for the differently cooled nanoparticles are small, but in correspondence with the structural changes.

The Opposite of Denial: Social Learning at the Onset of the Ebola Emergency in Liberia.

PubMed

Abramowitz, Sharon; McKune, Sarah Lindley; Fallah, Mosoka; Monger, Josephine; Tehoungue, Kodjo; Omidian, Patricia A

2017-01-01

This study analyzes findings from a rapid-response community-based qualitative research initiative to study the content of Ebola-related communications and the transmission of Ebola-related behaviors and practices through mass media communications and social learning in Monrovia, Liberia during August-September 2014. Thirteen neighborhoods in the common Monrovia media market were studied to appraise the reach of health communications and outreach regarding Ebola prevention and response measures. A World Health Organization (WHO) research team collected data on social learning and Ebola knowledge, attitudes, and practices through focus group-based discussions and key informant interviews over a 14-day period to assess the spread of information during a period of rapidly escalating crisis. Findings show that during a 2-week period, Monrovia neighborhood residents demonstrated rapid changes in beliefs about the source of Ebola, modes of contagion, and infection prevention and control (IPC) practices, discarding incorrect information. Changes in practices tended to lag behind the acquisition of learning. Findings also show that many continued to support conspiracy theories even as correct information was acquired. The implications for community engagement are substantial: (1) Under conditions of accelerating mortality, communities rapidly assimilate health information and abandon incorrect information; (2) Behavior change is likely to lag behind changes in beliefs due to local physical, structural, sociocultural, and institutional constraints; (3) Reports of "resistance" in Monrovia during the Ebola response were overstated and based on a limited number of incidents, and failed to account for specific local conditions and constraints.

Beyond context to the skyline: thinking in 3D.

PubMed

Hoagwood, Kimberly; Olin, Serene; Cleek, Andrew

2013-01-01

Sweeping and profound structural, regulatory, and fiscal changes are rapidly reshaping the contours of health and mental health practice. The community-based practice contexts described in the excellent review by Garland and colleagues are being fundamentally altered with different business models, regional networks, accountability standards, and incentive structures. If community-based mental health services are to remain viable, the two-dimensional and flat research and practice paradigm has to be replaced with three-dimensional thinking. Failure to take seriously the changes that are happening to the larger healthcare context and respond actively through significant system redesign will lead to the demise of specialty mental health services.

[Sleep disturbances in children with autistic spectrum disorders].

PubMed

Kelmanson, I A

2015-01-01

An association between sleep disorders and autistic spectrum disorders in children is considered. Characteristic variants of sleep disorders, including resistance to going to bed, frequent night awakenings, parasomnias, changes in sleep structure, primarily, the decrease in the percentage of rapid eye movement sleep, are presented. Attention is focused on the possibility of the direct relationship between sleep disturbance and the pathogenesis of autistic spectrum disorders. A role of pathological alterations in the production of neuromediators and morphological changes in the brain structures characteristic of autistic spectrum disorders in the genesis of sleep disorders in children is discussed. Possible non-pharmacological and pharmacological approaches are suggested.

Patterns of residual stresses due to welding

NASA Technical Reports Server (NTRS)

Botros, B. M.

1983-01-01

Residual stresses caused by welding result from the nonuniform rate of cooling and the restrained thermal contraction or non-uniform plastic deformation. From the zone of extremely high temperature at the weld, heat flows into both the adjoining cool body and the surrounding atmosphere. The weld metal solidifies under very rapid cooling. The plasticity of the hot metal allows adjustment initially, but as the structure cools the rigidity of the surrounding cold metal inhibits further contraction. The zone is compressed and the weld is put under tensile stresses of high magnitude. The danger of cracking in these structural elements is great. Change in specific volume is caused by the change in temperature.

Photonic Crystals: Tunable Design of Structural Colors Produced by Pseudo-1D Photonic Crystals of Graphene Oxide (Small 25/2016).

PubMed

Tong, Liping; Qi, Wei; Wang, Mengfan; Huang, Renliang; Su, Rongxin; He, Zhimin

2016-07-01

The production of structural colors based on graphene oxide (GO) pseudo-one-dimensional photonic crystals (p1D-PhCs) in the visible spectrum is reported on page 3433 by W. Qi and co-workers. The structural colors could be tuned by simply changing either the volume or concentration of the aqueous GO dispersion. Moreover, GO p1D-PhCs exhibit visible and rapid responsiveness to humidity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressure-induced structural change in MgSiO3 glass at pressures near the Earth's core–mantle boundary

NASA Astrophysics Data System (ADS)

Kono, Yoshio; Shibazaki, Yuki; Kenney-Benson, Curtis; Wang, Yanbin; Shen, Guoyin

2018-02-01

Knowledge of the structure and properties of silicate magma under extreme pressure plays an important role in understanding the nature and evolution of Earth’s deep interior. Here we report the structure of MgSiO3 glass, considered an analog of silicate melts, up to 111 GPa. The first (r1) and second (r2) neighbor distances in the pair distribution function change rapidly, with r1 increasing and r2 decreasing with pressure. At 53–62 GPa, the observed r1 and r2 distances are similar to the Si-O and Si-Si distances, respectively, of crystalline MgSiO3 akimotoite with edge-sharing SiO6 structural motifs. Above 62 GPa, r1 decreases, and r2 remains constant, with increasing pressure until 88 GPa. Above this pressure, r1 remains more or less constant, and r2 begins decreasing again. These observations suggest an ultrahigh-pressure structural change around 88 GPa. The structure above 88 GPa is interpreted as having the closest edge-shared SiO6 structural motifs similar to those of the crystalline postperovskite, with densely packed oxygen atoms. The pressure of the structural change is broadly consistent with or slightly lower than that of the bridgmanite-to-postperovskite transition in crystalline MgSiO3. These results suggest that a structural change may occur in MgSiO3 melt under pressure conditions corresponding to the deep lower mantle.

Shaping the future of the international satellite organizations

NASA Astrophysics Data System (ADS)

Wright, David

Most of the world's satellite communications traffic is carried by three organizations - Intelsat, Inmarsat, and Eutelsat. These three organizations are at the heart of the multibillion dollar communications satellite industry. The international satellite organizations (ISOs) generate hundreds of millions of dollars in revenue each year. They have purchased billions of dollars worth of satellites. Manufacturers have earned more billions from the sale of earth stations and the launchers used to put the satellites into orbit. The ISOs are at the leading edge of satellite technology in one of the fastest growing sectors in one of the world's fastest growing industries. The structure of the ISOs at the heart of this huge and rapidly growing industry is now under serious review. Changes in their institutional structure could ripple far beyond the organizations themselves. This paper reviews the existing structure of the ISOs, the pressures for structural change, and some of the consequences likely to result from change. Although all three ISOs are considered, most emphasis has been placed on Inmarsat.

The Burmese python genome reveals the molecular basis for extreme adaptation in snakes

PubMed Central

Castoe, Todd A.; de Koning, A. P. Jason; Hall, Kathryn T.; Card, Daren C.; Schield, Drew R.; Fujita, Matthew K.; Ruggiero, Robert P.; Degner, Jack F.; Daza, Juan M.; Gu, Wanjun; Reyes-Velasco, Jacobo; Shaney, Kyle J.; Castoe, Jill M.; Fox, Samuel E.; Poole, Alex W.; Polanco, Daniel; Dobry, Jason; Vandewege, Michael W.; Li, Qing; Schott, Ryan K.; Kapusta, Aurélie; Minx, Patrick; Feschotte, Cédric; Uetz, Peter; Ray, David A.; Hoffmann, Federico G.; Bogden, Robert; Smith, Eric N.; Chang, Belinda S. W.; Vonk, Freek J.; Casewell, Nicholas R.; Henkel, Christiaan V.; Richardson, Michael K.; Mackessy, Stephen P.; Bronikowski, Anne M.; Yandell, Mark; Warren, Wesley C.; Secor, Stephen M.; Pollock, David D.

2013-01-01

Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome. PMID:24297902

The Burmese python genome reveals the molecular basis for extreme adaptation in snakes.

PubMed

Castoe, Todd A; de Koning, A P Jason; Hall, Kathryn T; Card, Daren C; Schield, Drew R; Fujita, Matthew K; Ruggiero, Robert P; Degner, Jack F; Daza, Juan M; Gu, Wanjun; Reyes-Velasco, Jacobo; Shaney, Kyle J; Castoe, Jill M; Fox, Samuel E; Poole, Alex W; Polanco, Daniel; Dobry, Jason; Vandewege, Michael W; Li, Qing; Schott, Ryan K; Kapusta, Aurélie; Minx, Patrick; Feschotte, Cédric; Uetz, Peter; Ray, David A; Hoffmann, Federico G; Bogden, Robert; Smith, Eric N; Chang, Belinda S W; Vonk, Freek J; Casewell, Nicholas R; Henkel, Christiaan V; Richardson, Michael K; Mackessy, Stephen P; Bronikowski, Anne M; Bronikowsi, Anne M; Yandell, Mark; Warren, Wesley C; Secor, Stephen M; Pollock, David D

2013-12-17

Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome.

Rapid, High-Resolution Detection of Environmental Change over Continental Scales from Satellite Data - the Earth Observation Data Cube

NASA Technical Reports Server (NTRS)

Lewis, Adam; Lymburner, Leo; Purss, Matthew B. J.; Brooke, Brendan; Evans, Ben; Ip, Alex; Dekker, Arnold G.; Irons, James R.; Minchin, Stuart; Mueller, Norman

2015-01-01

The effort and cost required to convert satellite Earth Observation (EO) data into meaningful geophysical variables has prevented the systematic analysis of all available observations. To overcome these problems, we utilise an integrated High Performance Computing and Data environment to rapidly process, restructure and analyse the Australian Landsat data archive. In this approach, the EO data are assigned to a common grid framework that spans the full geospatial and temporal extent of the observations - the EO Data Cube. This approach is pixel-based and incorporates geometric and spectral calibration and quality assurance of each Earth surface reflectance measurement. We demonstrate the utility of the approach with rapid time-series mapping of surface water across the entire Australian continent using 27 years of continuous, 25 m resolution observations. Our preliminary analysis of the Landsat archive shows how the EO Data Cube can effectively liberate high-resolution EO data from their complex sensor-specific data structures and revolutionise our ability to measure environmental change.

Large Magneto-ionic Variations toward the Galactic Center Magnetar, PSR J1745-2900

NASA Astrophysics Data System (ADS)

Desvignes, G.; Eatough, R. P.; Pen, U. L.; Lee, K. J.; Mao, S. A.; Karuppusamy, R.; Schnitzeler, D. H. F. M.; Falcke, H.; Kramer, M.; Wucknitz, O.; Spitler, L. G.; Torne, P.; Liu, K.; Bower, G. C.; Cognard, I.; Lyne, A. G.; Stappers, B. W.

2018-01-01

Polarized radio emission from PSR J1745‑2900 has already been used to investigate the strength of the magnetic field in the Galactic center (GC), close to Sagittarius A*. Here we report how persistent radio emission from this magnetar, for over four years since its discovery, has revealed large changes in the observed Faraday rotation measure (RM), by up to 3500 rad m‑2 (a 5% fractional change). From simultaneous analysis of the dispersion measure, we determine that these fluctuations are dominated by variations in either the projected magnetic field or the free electron content within the GC, along the changing line of sight to the rapidly moving magnetar. From a structure function analysis of RM variations, and a recent epoch of rapid change of RM, we determine a minimum scale of magneto-ionic fluctuations of size ∼2 au at the GC distance, inferring PSR J1745‑2900 is just ∼0.1 pc behind an additional scattering screen.

Bioactive glasses: Importance of structure and properties in bone regeneration

NASA Astrophysics Data System (ADS)

Hench, Larry L.; Roki, Niksa; Fenn, Michael B.

2014-09-01

This review provides a brief background on the applications, mechanisms and genetics involved with use of bioactive glass to stimulate regeneration of bone. The emphasis is on the role of structural changes of the bioactive glasses, in particular Bioglass, which result in controlled release of osteostimulative ions. The review also summarizes the use of Raman spectroscopy, referred to hereto forward as bio-Raman spectroscopy, to obtain rapid, real time in vitro analysis of human cells in contact with bioactive glasses, and the osteostimulative dissolution ions that lead to osteogenesis. The bio-Raman studies support the results obtained from in vivo studies of bioactive glasses, as well as extensive cell and molecular biology studies, and thus offers an innovative means for rapid screening of new bioactive materials while reducing the need for animal testing.

A Preliminary Assessment of Barotrauma Injuries and Acclimation Studies for Three Fish Species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Richard S.; Walker, Ricardo W.; Stephenson, John R.

Fish that pass hydro structures either through turbine passage, deep spill, or other deep pathways can experience rapid decreases in pressure that can result in barotrauma. In addition to morphology and physiology of the fish’s swim bladder, the severity of barotrauma is directly related to the volume of undissolved gas in fish prior to rapid decompression and the lowest pressure the fish experience as they pass hydro structures (termed the “nadir”). The volume of undissolved gas in fish is influenced by the depth of acclimation (the pressure at which the fish is neutrally buoyant); therefore, determining the depth where fishmore » are neutrally buoyant is a critical precursor to determining the relationship between pressure changes and injury or mortality.« less

Ecological dynamics across the Arctic associated with recent climate change.

PubMed

Post, Eric; Forchhammer, Mads C; Bret-Harte, M Syndonia; Callaghan, Terry V; Christensen, Torben R; Elberling, Bo; Fox, Anthony D; Gilg, Olivier; Hik, David S; Høye, Toke T; Ims, Rolf A; Jeppesen, Erik; Klein, David R; Madsen, Jesper; McGuire, A David; Rysgaard, Søren; Schindler, Daniel E; Stirling, Ian; Tamstorf, Mikkel P; Tyler, Nicholas J C; van der Wal, Rene; Welker, Jeffrey; Wookey, Philip A; Schmidt, Niels Martin; Aastrup, Peter

2009-09-11

At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These rapid changes may be a bellwether of changes to come at lower latitudes and have the potential to affect ecosystem services related to natural resources, food production, climate regulation, and cultural integrity. We highlight areas of ecological research that deserve priority as the Arctic continues to warm.

Using vibrational molecular spectroscopy to reveal association of steam-flaking induced carbohydrates molecular structural changes with grain fractionation, biodigestion and biodegradation

NASA Astrophysics Data System (ADS)

Xu, Ningning; Liu, Jianxin; Yu, Peiqiang

2018-04-01

Advanced vibrational molecular spectroscopy has been developed as a rapid and non-destructive tool to reveal intrinsic molecular structure conformation of biological tissues. However, this technique has not been used to systematically study flaking induced structure changes at a molecular level. The objective of this study was to use vibrational molecular spectroscopy to reveal association between steam flaking induced CHO molecular structural changes in relation to grain CHO fractionation, predicted CHO biodegradation and biodigestion in ruminant system. The Attenuate Total Reflectance Fourier-transform Vibrational Molecular Spectroscopy (ATR-Ft/VMS) at SRP Key Lab of Molecular Structure and Molecular Nutrition, Ministry of Agriculture Strategic Research Chair Program (SRP, University of Saskatchewan) was applied in this study. The fractionation, predicted biodegradation and biodigestion were evaluated using the Cornell Net Carbohydrate Protein System. The results show that: (1) The steam flaking induced significant changes in CHO subfractions, CHO biodegradation and biodigestion in ruminant system. There were significant differences between non-processed (raw) and steam flaked grain corn (P < .01); (2) The ATR-Ft/VMS molecular technique was able to detect the processing induced CHO molecular structure changes; (3) Induced CHO molecular structure spectral features are significantly correlated (P < .05) to CHO subfractions, CHO biodegradation and biodigestion and could be applied to potentially predict CHO biodegradation (R2 = 0.87, RSD = 0.74, P < .01) and intestinal digestible undegraded CHO (R2 = 0.87, RSD = 0.24, P < .01). In summary, the processing induced molecular CHO structure changes in grain corn could be revealed by the ATR-Ft/VMS vibrational molecular spectroscopy. These molecular structure changes in grain were potentially associated with CHO biodegradation and biodigestion.

Structural defects and variations in the HIV-1 nef gene from rapid, slow and non-progressor children.

PubMed

Casartelli, Nicoletta; Di Matteo, Gigliola; Argentini, Claudio; Cancrini, Caterina; Bernardi, Stefania; Castelli, Guido; Scarlatti, Gabriella; Plebani, Anna; Rossi, Paolo; Doria, Margherita

2003-06-13

Evaluation of sequence evolution as well as structural defects and mutations of the human immunodeficiency virus-type 1 (HIV-1) nef gene in relation to disease progression in infected children. We examined a large number of nef alleles sequentially derived from perinatally HIV-1-infected children with different rates of disease progression: six non-progressors (NPs), four rapid progressors (RPs), and three slow progressors (SPs). Nef alleles (182 total) were isolated from patients' peripheral blood mononuclear cells (PBMCs), sequenced and analysed for their evolutionary pattern, frequency of mutations and occurrence of amino acid variations associated with different stages of disease. The evolution rate of the nef gene apparently correlated with CD4+ decline in all progression groups. Evidence for rapid viral turnover and positive selection for changes were found only in two SPs and two RPs respectively. In NPs, a higher proportion of disrupted sequences and mutations at various functional motifs were observed. Furthermore, NP-derived Nef proteins were often changed at residues localized in the folded core domain at cytotoxic T lymphocytes (CTL) epitopes (E(105), K(106), E(110), Y(132), K(164), and R(200)), while other residues outside the core domain are more often changed in RPs (A(43)) and SPs (N(173) and Y(214)). Our results suggest a link between nef gene functions and the progression rate in HIV-1-infected children. Moreover, non-progressor-associated variations in the core domain of Nef, together with the genetic analysis, suggest that nef gene evolution is shaped by an effective immune system in these patients.

Molecular Evolution of Grass Stomata.

PubMed

Chen, Zhong-Hua; Chen, Guang; Dai, Fei; Wang, Yizhou; Hills, Adrian; Ruan, Yong-Ling; Zhang, Guoping; Franks, Peter J; Nevo, Eviatar; Blatt, Michael R

2017-02-01

Grasses began to diversify in the late Cretaceous Period and now dominate more than one third of global land area, including three-quarters of agricultural land. We hypothesize that their success is likely attributed to the evolution of highly responsive stomata capable of maximizing productivity in rapidly changing environments. Grass stomata harness the active turgor control mechanisms present in stomata of more ancient plant lineages, maximizing several morphological and developmental features to ensure rapid responses to environmental inputs. The evolutionary development of grass stomata appears to have been a gradual progression. Therefore, understanding the complex structures, developmental events, regulatory networks, and combinations of ion transporters necessary to drive rapid stomatal movement may inform future efforts towards breeding new crop varieties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Population-level genetic variation and climate change in a biodiversity hotspot

PubMed Central

2017-01-01

Introduction Estimated future climate scenarios can be used to predict where hotspots of endemism may occur over the next century, but life history, ecological and genetic traits will be important in informing the varying responses within myriad taxa. Essential to predicting the consequences of climate change to individual species will be an understanding of the factors that drive genetic structure within and among populations. Here, I review the factors that influence the genetic structure of plant species in California, but are applicable elsewhere; existing levels of genetic variation, life history and ecological characteristics will affect the ability of an individual taxon to persist in the presence of anthropogenic change. Factors influencing the distribution of genetic variation Persistence in the face of climate change is likely determined by life history characteristics: dispersal ability, generation time, reproductive ability, degree of habitat specialization, plant–insect interactions, existing genetic diversity and availability of habitat or migration corridors. Existing levels of genetic diversity in plant populations vary based on a number of evolutionary scenarios that include endemism, expansion since the last glacial maximum, breeding system and current range sizes. Regional priorities and examples A number of well-documented examples are provided from the California Floristic Province. Some predictions can be made for the responses of plant taxa to rapid environmental changes based on geographic position, evolutionary history, existing genetic variation, and ecological amplitude. Conclusions, Solutions and Recommendations The prediction of how species will respond to climate change will require a synthesis drawing from population genetics, geography, palaeontology and ecology. The important integration of the historical factors that have shaped the distribution and existing genetic structure of California’s plant taxa will enable us to predict and prioritize the conservation of species and areas most likely to be impacted by rapid climate change, human disturbance and invasive species. PMID:28069633

Population-level genetic variation and climate change in a biodiversity hotspot.

PubMed

Schierenbeck, Kristina A

2017-01-01

Estimated future climate scenarios can be used to predict where hotspots of endemism may occur over the next century, but life history, ecological and genetic traits will be important in informing the varying responses within myriad taxa. Essential to predicting the consequences of climate change to individual species will be an understanding of the factors that drive genetic structure within and among populations. Here, I review the factors that influence the genetic structure of plant species in California, but are applicable elsewhere; existing levels of genetic variation, life history and ecological characteristics will affect the ability of an individual taxon to persist in the presence of anthropogenic change. Persistence in the face of climate change is likely determined by life history characteristics: dispersal ability, generation time, reproductive ability, degree of habitat specialization, plant-insect interactions, existing genetic diversity and availability of habitat or migration corridors. Existing levels of genetic diversity in plant populations vary based on a number of evolutionary scenarios that include endemism, expansion since the last glacial maximum, breeding system and current range sizes. A number of well-documented examples are provided from the California Floristic Province. Some predictions can be made for the responses of plant taxa to rapid environmental changes based on geographic position, evolutionary history, existing genetic variation, and ecological amplitude. The prediction of how species will respond to climate change will require a synthesis drawing from population genetics, geography, palaeontology and ecology. The important integration of the historical factors that have shaped the distribution and existing genetic structure of California's plant taxa will enable us to predict and prioritize the conservation of species and areas most likely to be impacted by rapid climate change, human disturbance and invasive species. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Biodegradation of the chitin-protein complex in crustacean cuticle

USGS Publications Warehouse

Artur, Stankiewicz B.; Mastalerz, Maria; Hof, C.H.J.; Bierstedt, A.; Flannery, M.B.; Briggs, D.E.G.; Evershed, R.P.

1998-01-01

Arthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative analysis of amino acids (by HPLC) and chitin showed that the major loss of proteins and chitin occurred between weeks 1 and 2. After 8 weeks tyrosine, tryptophan and valine are the most prominent amino acid moieties, showing their resistance to degradation. The presence of cyclic ketones in the pyrolysates indicates that mucopolysaccharides or other bound non-chitinous carbohydrates are also resistant to decay. There is no evidence of structural degradation of chitin prior to 8 weeks when FTIR revealed a reduction in chitin-specific bands. The chemical changes are paralleled by structural changes in the cuticle, which becomes an increasingly open structure consisting of loose chitinous fibres. The rapid rate of decay in the experiments suggests that where chitin and protein are preserved in fossil cuticles degradation must have been inhibited.Arthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative analysis of amino acids (by HPLC) and chitin showed that the major loss of proteins and chitin occurred between weeks 1 and 2. After 8 weeks tyrosine, tryptophan and valine are the most prominent amino acid moieties, showing their resistance to degradation. The presence of cyclic ketones in the pyrolysates indicates that mucopolysaccharides or other bound non-chitinous carbohydrates are also resistant to decay. There is no evidence of structural degradation of chitin prior to 8 weeks when FTIR revealed a reduction in chitin-specific bands. The chemical changes are paralleled by structural changes in the cuticle, which becomes an increasingly open structure consisting of loose chitinous fibres. The rapid rate of decay in the experiments suggests, that where chitin and protein are preserved in fossil cuticles degradation must have been inhibited.

Insurance Agencies' Organizational Learning in a Turbulent Time: A Community of Practice Perspective

ERIC Educational Resources Information Center

Gau, Wen-Bing; Wen, Chen-Hao

2011-01-01

In a turbulent time, communities of practice (CoPs) have become an important mechanism to develop organizational learning. Because of the rapid changes of global market and population structure, organizations in the private sector keep examining their leaning processes to adjust themselves to different challenges. However, few studies try to…

Widespread increase of tree mortality rates in the western United States

Treesearch

Phillip J. van Mantgem; Nathan L. Stephenson; John C. Byrne; Lori D. Daniels; Jerry F. Franklin; Peter Z. Fule; Mark E. Harmon; Andrew J. Larson; Jeremy M. Smith; Alan H. Taylor; Thomas T. Veblen

2009-01-01

Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29...

Minimal standards for describing new species belonging to the families Campylobacteraceae and Helicobacteraceae: Campylobacter, Arcobacter, Helicobacter and Wolinella spp

USDA-ARS?s Scientific Manuscript database

Ongoing changes in taxonomic methods, and in the rapid development of the taxonomic structure of species assigned to the Epsilonproteobacteria have lead the International Committee of Systematic Bacteriology Subcommittee on the Taxonomy of Campylobacter and Related Bacteria to discuss significant up...

Organizing for Life-Long Learning. Occasional Paper No. 2.

ERIC Educational Resources Information Center

Pacific Association for Continuing Education, Burnaby (British Columbia).

The statement reflects Canada's growing interest in adult education. Lifelong learning is viewed as necessary for coping with a complex and rapidly changing society and additional benefits of adult education can be seen in terms of cost benefits and the use of existing educational structures. Social factors influencing the need for adult learning…

Visual indication of enviromental humidity by using poly(ionic liquid) photonic crystals.

PubMed

Huang, Jing; Tao, Cheng-an; An, Qi; Lin, Changxu; Li, Xuesong; Xu, Dan; Wu, Yiguang; Li, Xiaogang; Shen, Dezhong; Li, Guangtao

2010-06-21

The combination of poly (ionic liquid) and photonic structure affords a new class of self-reporting humidity sensory materials with excellent reversibility, which are able to rapidly, sensitively and visually indicate environmental humidity with colour change from blue to green, orange, and red, covering the whole visible range.

Cultural and Biological Adaptations to Deprivation: The Northern Ojibwa Case.

ERIC Educational Resources Information Center

Bishop, Charles A.

After the fur trade reached the Ojibwa during the early 17th Century, tribe structure and function rapidly changed. The intensity of social life increased as the Ojibwa and neighboring tribes gathered to exchange fur pelts for European items. Trade became so important that intertribal hostilities arose and an almost unrestrictive slaughter of…

Piecing Together Family Social Work in Mainland China

ERIC Educational Resources Information Center

Sim, Timothy

2008-01-01

As rapid economic and sociopolitical development brings about drastic changes in family structure and processes in China, many social concerns arise. Through a review of journal articles published over a period of 28 years (1979-2006) in social work and related disciplines in China, this article presents a glimpse of family social work using the…

Transformational Leadership in Turkish Schools

ERIC Educational Resources Information Center

Kocabas, Ibrahim

2007-01-01

Leadership is a subject that is as old as the history of humans, and it still continues its currency. Rapid changes in social structure have affected educational systems and the roles and behaviors of those who are managing these systems. School administrators need to have international supervision in today's global system. The intensive use of…

The Socializing Role of Early Childhood Development and Education (ECD) in the 21st Century.

ERIC Educational Resources Information Center

Fthenakis, Wassilios E.

Noting demographic and socio-political shifts in Europe, this paper discusses challenges facing early childhood education in providing children with sufficient competence to cope successfully with discontinuities in their lives caused by rapidly changing social conditions and family structure. The paper outlines some contextual conditions which…

Youth Sport as a Component of Organized Afterschool Programs

ERIC Educational Resources Information Center

Coatsworth, J. Douglas; Conroy, David E.

2007-01-01

Organized afterschool programs have received increased attention over the past two decades because of changes in family demographics and in society's structures for supervising and socializing youth. The number of afterschool programs has been rapidly expanding to meet the increased need. However, not all youth in need are being reached, and the…

Schooling and Industrialization in China: Gender Differences in School Enrollment

ERIC Educational Resources Information Center

Lee, Ming-Hsuan

2014-01-01

The rapid decrease in gender inequality in education over the past several decades in China has drawn significant attention in the existing literature. Several factors have been proposed or examined to explain this decrease. However, few studies have examined this topic from the perspective of the changing job structure and skill requirements in…

The Early Childhood Education of Disadvantaged Children in China

ERIC Educational Resources Information Center

Song, Zhanmei; Zhu, Jiaxiong; Xia, Zhuyun; Wu, Xin

2014-01-01

Since 2010, the Chinese government has adopted a series of services and policies to provide early childhood education for disadvantaged children. The rapid economic development and urbanisation process since the mid-1980s have led to great changes in social structure and demographics in China. This creates new challenges for the education of…

EBOOK.EXE: A Desktop Authoring Tool for HURAA.

ERIC Educational Resources Information Center

Hu, Xiangen; Mathews, Eric; Graesser, Arthur C.; Susarla, Suresh

The development of authoring tools for intelligent systems is an important step for creating, maintaining, and structuring content in a quick and easy manner. It has the benefit of allowing for a rapid change to new domains or topics for tutoring. The development of such tools requires functional control, access protection, ease of learning, and…

A Planning Process Addresses an Organizational and Support Crisis in Information Technology.

ERIC Educational Resources Information Center

Nelson, Keith R.; Davenport, Richard W.

1996-01-01

An institutionwide strategic planning effort at Central Michigan University, in response to a need for rapid and significant changes in its information technology infrastructure, is outlined. The effort resulted in a matrix governance structure for information technology that acknowledges the value of both distributed support and a strong central…

Structural and kinetic analysis of the COP9-Signalosome activation and the cullin-RING ubiquitin ligase deneddylation cycle

PubMed Central

Mosadeghi, Ruzbeh; Reichermeier, Kurt M; Winkler, Martin; Schreiber, Anne; Reitsma, Justin M; Zhang, Yaru; Stengel, Florian; Cao, Junyue; Kim, Minsoo; Sweredoski, Michael J; Hess, Sonja; Leitner, Alexander; Aebersold, Ruedi; Peter, Matthias; Deshaies, Raymond J; Enchev, Radoslav I

2016-01-01

The COP9-Signalosome (CSN) regulates cullin–RING ubiquitin ligase (CRL) activity and assembly by cleaving Nedd8 from cullins. Free CSN is autoinhibited, and it remains unclear how it becomes activated. We combine structural and kinetic analyses to identify mechanisms that contribute to CSN activation and Nedd8 deconjugation. Both CSN and neddylated substrate undergo large conformational changes upon binding, with important roles played by the N-terminal domains of Csn2 and Csn4 and the RING domain of Rbx1 in enabling formation of a high affinity, fully active complex. The RING domain is crucial for deneddylation, and works in part through conformational changes involving insert-2 of Csn6. Nedd8 deconjugation and re-engagement of the active site zinc by the autoinhibitory Csn5 glutamate-104 diminish affinity for Cul1/Rbx1 by ~100-fold, resulting in its rapid ejection from the active site. Together, these mechanisms enable a dynamic deneddylation-disassembly cycle that promotes rapid remodeling of the cellular CRL network. DOI: http://dx.doi.org/10.7554/eLife.12102.001 PMID:27031283

Tropical vegetation evidence for rapid sea level changes associated with Heinrich Events

NASA Astrophysics Data System (ADS)

González, Catalina; Dupont, Lydie M.

2010-03-01

A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3. Rapid and abrupt expansions of salt marsh vegetation in tropical South America are associated with north Atlantic Heinrich Events stadials (HE-stadials). Intervals of salt marsh expansion have an internal structure, which consists of a recurrent alternation of species that starts with pollen increments of Chenopodiaceae, that are followed by increments of grasses, and subsequently by increments of Cyperaceae. This pattern suggests a successional process that is determined by the close relationship between sea-level and plant community dynamics. The salt tolerant Chenopodiaceae, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE-stadials, causing the continued recruitment of pioneer species, which are the only ones tolerating rapid rates of disturbance. Once sea-level rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species. These results add to the scarce knowledge on the dynamics of tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes following Antarctic climate variability.

Numerical simulation of the rapid intensification of Hurricane Katrina (2005): Sensitivity to boundary layer parameterization schemes

NASA Astrophysics Data System (ADS)

Liu, Jianjun; Zhang, Feimin; Pu, Zhaoxia

2017-04-01

Accurate forecasting of the intensity changes of hurricanes is an important yet challenging problem in numerical weather prediction. The rapid intensification of Hurricane Katrina (2005) before its landfall in the southern US is studied with the Advanced Research version of the WRF (Weather Research and Forecasting) model. The sensitivity of numerical simulations to two popular planetary boundary layer (PBL) schemes, the Mellor-Yamada-Janjic (MYJ) and the Yonsei University (YSU) schemes, is investigated. It is found that, compared with the YSU simulation, the simulation with the MYJ scheme produces better track and intensity evolution, better vortex structure, and more accurate landfall time and location. Large discrepancies (e.g., over 10 hPa in simulated minimum sea level pressure) are found between the two simulations during the rapid intensification period. Further diagnosis indicates that stronger surface fluxes and vertical mixing in the PBL from the simulation with the MYJ scheme lead to enhanced air-sea interaction, which helps generate more realistic simulations of the rapid intensification process. Overall, the results from this study suggest that improved representation of surface fluxes and vertical mixing in the PBL is essential for accurate prediction of hurricane intensity changes.

Assessing surface albedo change and its induced radiation budget under rapid urbanization with Landsat and GLASS data

NASA Astrophysics Data System (ADS)

Hu, Yonghong; Jia, Gensuo; Pohl, Christine; Zhang, Xiaoxuan; van Genderen, John

2016-02-01

Radiative forcing (RF) induced by land use (mainly surface albedo) change is still not well understood in climate change science, especially the effects of changes in urban albedo due to rapid urbanization on the urban radiation budget. In this study, a modified RF derivation approach based on Landsat images was used to quantify changes in the solar radiation budget induced by variations in surface albedo in Beijing from 2001 to 2009. Field radiation records from a Beijing meteorological station were used to identify changes in RF at the local level. There has been rapid urban expansion over the last decade, with the urban land area increasing at about 3.3 % annually from 2001 to 2009. This has modified three-dimensional urban surface properties, resulting in lower albedo due to complex building configurations of urban centers and higher albedo on flat surfaces of suburban areas and cropland. There was greater solar radiation (6.93 × 108 W) in the urban center in 2009 than in 2001. However, large cropland and urban fringe areas caused less solar radiation absorption. RF increased with distance from the urban center (less than 14 km) and with greater urbanization, with the greatest value being 0.41 W/m2. The solar radiation budget in urban areas was believed to be mainly influenced by urban structural changes in the horizontal and vertical directions. Overall, the results presented herein indicate that cumulative urbanization impacts on the natural radiation budget could evolve into an important driver of local climate change.

Challenges in Accommodating Volume Change of Si Anodes for Li-Ion Batteries

PubMed Central

Ko, Minseong; Chae, Sujong; Cho, Jaephil

2015-01-01

Si has been considered as a promising alternative anode for next-generation Li-ion batteries (LIBs) because of its high theoretical energy density, relatively low working potential, and abundance in nature. However, Si anodes exhibit rapid capacity decay and an increase in the internal resistance, which are caused by the large volume changes upon Li insertion and extraction. This unfortunately limits their practical applications. Therefore, managing the total volume change remains a critical challenge for effectively alleviating the mechanical fractures and instability of solid-electrolyte-interphase products. In this regard, we review the recent progress in volume-change-accommodating Si electrodes and investigate their ingenious structures with significant improvements in the battery performance, including size-controlled materials, patterned thin films, porous structures, shape-preserving shell designs, and graphene composites. These representative approaches potentially overcome the large morphologic changes in the volume of Si anodes by securing the strain relaxation and structural integrity in the entire electrode. Finally, we propose perspectives and future challenges to realize the practical application of Si anodes in LIB systems. PMID:27525208

Exploring the structure of high temperature, iron-bearing liquids

DOE PAGES

Wilding, Martin; Benmore, Chris; Weber, Rick; ...

2015-06-25

This paper describes the direct measurements of the structure of iron-bearing liquids using a combination of containerless techniques and in–situ high energy x-ray diffraction. These capabilities provide data that is important to help model and optimize processes such as smelting, steel making, and controlling slag chemistry. A successful programme of liquid studies has been undertaken and the Advanced Photon Source using these combined techniques which include the provision of gas mixing and the control of pO₂ and the changing influence of mixed valance elements. It is possible to combine rapid image acquisition with quenching of liquids to obtain the fullmore » diffraction patterns of deeply supercooled liquids and the metastable supercooled liquid regime, where the liquid structures and viscosity change most dramatically, can also be explored.« less

The Structure of Triton's Lower Atmosphere

NASA Astrophysics Data System (ADS)

Bosh, Amanda

1995-07-01

With the occultation of Tr148 (McDonald and Elliot, submitted) in August 1995, we have the opportunity to distinguish between two competing models for Triton's lower atmosphere (Tyler et al. 1989; Strobel and Summers 1994). Additionally, we will be acquiring data on an atmosphere that has been predicted to be changing quite rapidly (Hansen and Paige 1992; Spencer and Moore 1992). High quality occultation data sets are crucial for testing these theories and establishing the changing state of Triton's atmosphere.

CDS Re Mix

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

CDS (Change Detection Systems) is a mechanism for rapid visual analysis using complex image alignment algorithms. CDS is controlled with a simple interface that has been designed for use for anyone that can operate a digital camera. A challenge of complex industrial systems like nuclear power plants is to accurately identify changes in systems, structures and components that may critically impact the operation of the facility. CDS can provide a means of early intervention before the issues evolve into safety and production challenges.

Characteristic Changes in Cell Surface Glycosylation Accompany Intestinal Epithelial Cell (IEC) Differentiation: High Mannose Structures Dominate the Cell Surface Glycome of Undifferentiated Enterocytes*

PubMed Central

Park, Dayoung; Brune, Kristin A.; Mitra, Anupam; Marusina, Alina I.; Maverakis, Emanual; Lebrilla, Carlito B.

2015-01-01

Changes in cell surface glycosylation occur during the development and differentiation of cells and have been widely correlated with the progression of several diseases. Because of their structural diversity and sensitivity to intra- and extracellular conditions, glycans are an indispensable tool for analyzing cellular transformations. Glycans present on the surface of intestinal epithelial cells (IEC) mediate interactions with billions of native microorganisms, which continuously populate the mammalian gut. A distinct feature of IECs is that they differentiate as they migrate upwards from the crypt base to the villus tip. In this study, nano-LC/ESI QTOF MS profiling was used to characterize the changes in glycosylation that correspond to Caco-2 cell differentiation. As Caco-2 cells differentiate to form a brush border membrane, a decrease in high mannose type glycans and a concurrent increase in fucosylated and sialylated complex/hybrid type glycans were observed. At day 21, when cells appear to be completely differentiated, remodeling of the cell surface glycome ceases. Differential expression of glycans during IEC maturation appears to play a key functional role in regulating the membrane-associated hydrolases and contributes to the mucosal surface innate defense mechanisms. Developing methodologies to rapidly identify changes in IEC surface glycans may lead to a rapid screening approach for a variety of disease states affecting the GI tract. PMID:26355101

Insights into Rapid Modulation of Neuroplasticity by Brain Estrogens

PubMed Central

Woolfrey, Kevin M.; Penzes, Peter

2013-01-01

Converging evidence from cellular, electrophysiological, anatomic, and behavioral studies suggests that the remodeling of synapse structure and function is a critical component of cognition. This modulation of neuroplasticity can be achieved through the actions of numerous extracellular signals. Moreover, it is thought that it is the integration of different extracellular signals regulation of neuroplasticity that greatly influences cognitive function. One group of signals that exerts powerful effects on multiple neurologic processes is estrogens. Classically, estrogens have been described to exert their effects over a period of hours to days. However, there is now increasing evidence that estrogens can rapidly influence multiple behaviors, including those that require forebrain neural circuitry. Moreover, these effects are found in both sexes. Critically, it is now emerging that the modulation of cognition by rapid estrogenic signaling is achieved by activation of specific signaling cascades and regulation of synapse structure and function, cumulating in the rewiring of neural circuits. The importance of understanding the rapid effects of estrogens on forebrain function and circuitry is further emphasized as investigations continue to consider the potential of estrogenic-based therapies for neuropathologies. This review focuses on how estrogens can rapidly influence cognition and the emerging mechanisms that underlie these effects. We discuss the potential sources and the biosynthesis of estrogens within the brain and the consequences of rapid estrogenic-signaling on the remodeling of neural circuits. Furthermore, we argue that estrogens act via distinct signaling pathways to modulate synapse structure and function in a manner that may vary with cell type, developmental stage, and sex. Finally, we present a model in which the coordination of rapid estrogenic-signaling and activity-dependent stimuli can result in long-lasting changes in neural circuits, contributing to cognition, with potential relevance for the development of novel estrogenic-based therapies for neurodevelopmental or neurodegenerative disorders. PMID:24076546

Schooling in modern Europe exploring major issues and their ramifications

NASA Astrophysics Data System (ADS)

Husén, Torsten

1993-11-01

Basing its arguments on a major study conducted on behalf of the Academia Europaea by a study group coordinated by the author, this paper sets out a number of important findings concerning problems besetting schooling in modern Europe. The paper begins by stressing the importance of studying the state of European education at a particularly significant time when major political changes are taking place, trade and labour markets are in a process of rapid integration, schools as institutions are becoming increasingly complex and there is a need to establish a new European identity and consciousness. The main questions examined, against the current background of industrialization, urbanization, changing demography and growing European integration, are those relating particularly to educational response to growing international competition and the consequences of changing family structure. Among problems considered are those arising from the changing capacity of schools to provide a substitute for the family and other influences in modern society at a time when, for various reasons, these are declining and schooling is generally being prolonged. Priority areas proposed for school education in the new circumstances include the promotion of European citizenship, the teaching of foreign languages to all, a preparation for working life geared to its rapidly changing structure and the expansion of appropriate scientific and technological education. The need to find solutions to the problems of educating immigrant groups and to develop evaluation systems in order to monitor quality maintenance are particularly highlighted.

Sequential Self-Folding Structures by 3D Printed Digital Shape Memory Polymers

NASA Astrophysics Data System (ADS)

Mao, Yiqi; Yu, Kai; Isakov, Michael S.; Wu, Jiangtao; Dunn, Martin L.; Jerry Qi, H.

2015-09-01

Folding is ubiquitous in nature with examples ranging from the formation of cellular components to winged insects. It finds technological applications including packaging of solar cells and space structures, deployable biomedical devices, and self-assembling robots and airbags. Here we demonstrate sequential self-folding structures realized by thermal activation of spatially-variable patterns that are 3D printed with digital shape memory polymers, which are digital materials with different shape memory behaviors. The time-dependent behavior of each polymer allows the temporal sequencing of activation when the structure is subjected to a uniform temperature. This is demonstrated via a series of 3D printed structures that respond rapidly to a thermal stimulus, and self-fold to specified shapes in controlled shape changing sequences. Measurements of the spatial and temporal nature of self-folding structures are in good agreement with the companion finite element simulations. A simplified reduced-order model is also developed to rapidly and accurately describe the self-folding physics. An important aspect of self-folding is the management of self-collisions, where different portions of the folding structure contact and then block further folding. A metric is developed to predict collisions and is used together with the reduced-order model to design self-folding structures that lock themselves into stable desired configurations.

How is the fitness landscaped upon which life evolves selected?

NASA Astrophysics Data System (ADS)

Deem, Michael

2008-03-01

We investigate the selective forces that promote the emergence of modularity in nature. We demonstrate the spontaneous emergence of modularity in a population of individuals that evolve in a changing environment. We show that the level of modularity correlates with the rapidity and severity of environmental change. The modularity arises as a synergistic response to the noise in the environment in the presence of horizontal gene transfer. We suggest that the hierarchical structure observed in the natural world may be a broken symmetry state, which generically results from evolution in a changing environment. The existence of such structure, therefore, need not necessarily rest on intelligent design or the anthropic principle. 1) J. Sun and M. W. Deem, Phys. Rev. Lett., to appear., arXiv:0710.3436

Measuring and modelling the structure of chocolate

NASA Astrophysics Data System (ADS)

Le Révérend, Benjamin J. D.; Fryer, Peter J.; Smart, Ian; Bakalis, Serafim

2015-01-01

The cocoa butter present in chocolate exists as six different polymorphs. To achieve the desired crystal form (βV), traditional chocolate manufacturers use relatively slow cooling (<2°C/min). A newer generation of rapid cooling systems has been suggested requiring further understanding of fat crystallisation. To allow better control and understanding of these processes and newer rapid cooling processes, it is necessary to understand both heat transfer and crystallization kinetics. The proposed model aims to predict the temperature in the chocolate products during processing as well as the crystal structure of cocoa butter throughout the process. A set of ordinary differential equations describes the kinetics of fat crystallisation. The parameters were obtained by fitting the model to a set of DSC curves. The heat transfer equations were coupled to the kinetic model and solved using commercially available CFD software. A method using single crystal XRD was developed using a novel subtraction method to quantify the cocoa butter structure in chocolate directly and results were compared to the ones predicted from the model. The model was proven to predict phase change temperature during processing accurately (±1°C). Furthermore, it was possible to correctly predict phase changes and polymorphous transitions. The good agreement between the model and experimental data on the model geometry allows a better design and control of industrial processes.

Effect of rapid thermal annealing on nanocrystalline TiO2 thin films synthesized by swift heavy ion irradiation

NASA Astrophysics Data System (ADS)

Thakurdesai, Madhavi; Kanjilal, D.; Bhattacharyya, Varsha

2012-08-01

Irradiation by swift heavy ions (SHI) is unique tool to synthesize nanocrystalline thin films. We have reported transformation of 100 nm thick amorphous films into nanocrystalline film due to irradiation by 100 MeV Ag ion beam. Oblate shaped nanoparticles having anatase phase of TiO2 were formed on the surface of the irradiated films. In the present investigation, these films are annealed at 350 °C for 2 min in oxygen atmosphere by Rapid Thermal Annealing (RTA) method. During RTA processing, the temperature rises abruptly and this thermal instability is expected to alter surface morphology, structural and optical properties of nanocrystalline TiO2 thin films. Thus in the present work, effect of RTA on SHI induced nanocrystalline thin films of TiO2 is studied. The effect of RTA processing on the shape and size of TiO2 nanoparticles is studied by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Glancing Angle X-ray Diffraction (GAXRD) studies are carried to investigate structural changes induced by RTA processing. Optical characterization is carried out by UV-vis spectroscopy and photoluminescence (PL) spectroscopy. The changes observed in structural and optical properties of nanocrystalline TiO2 thin films after RTA processing are attributed to the annihilation of SHI induced defects.

Rapid evolution leads to differential population dynamics and top-down control in resurrected Daphnia populations.

PubMed

Goitom, Eyerusalem; Kilsdonk, Laurens J; Brans, Kristien; Jansen, Mieke; Lemmens, Pieter; De Meester, Luc

2018-01-01

There is growing evidence of rapid genetic adaptation of natural populations to environmental change, opening the perspective that evolutionary trait change may subsequently impact ecological processes such as population dynamics, community composition, and ecosystem functioning. To study such eco-evolutionary feedbacks in natural populations, however, requires samples across time. Here, we capitalize on a resurrection ecology study that documented rapid and adaptive evolution in a natural population of the water flea Daphnia magna in response to strong changes in predation pressure by fish, and carry out a follow-up mesocosm experiment to test whether the observed genetic changes influence population dynamics and top-down control of phytoplankton. We inoculated populations of the water flea D. magna derived from three time periods of the same natural population known to have genetically adapted to changes in predation pressure in replicate mesocosms and monitored both Daphnia population densities and phytoplankton biomass in the presence and absence of fish. Our results revealed differences in population dynamics and top-down control of algae between mesocosms harboring populations from the time period before, during, and after a peak in fish predation pressure caused by human fish stocking. The differences, however, deviated from our a priori expectations. An S-map approach on time series revealed that the interactions between adults and juveniles strongly impacted the dynamics of populations and their top-down control on algae in the mesocosms, and that the strength of these interactions was modulated by rapid evolution as it occurred in nature. Our study provides an example of an evolutionary response that fundamentally alters the processes structuring population dynamics and impacts ecosystem features.

Light activation of the LOV protein Vivid generates a rapidly exchanging dimer†‡

PubMed Central

Zoltowski, Brian D.; Crane, Brian R.

2009-01-01

The fungal photoreceptor Vivid (VVD) plays an important role in the adaptation of blue-light responses in Neurospora crassa. VVD, an FAD-binding LOV (Light, Oxygen, Voltage) protein, couples light-induced cysteinyl-adduct formation at the flavin ring to conformational changes in the N-terminal cap (Ncap) of the VVD PAS domain. Size-exclusion chromatography (SEC), equilibrium ultracentrifugation, and static and dynamic light scattering show that these conformational changes generate a rapidly exchanging VVD dimer, with an expanded hydrodynamic radius. A three-residue N-terminal β-turn that assumes two different conformations in a crystal structure of a VVD C71V variant is essential for light-state dimerization. Residue substitutions at a critical hinge between the Ncap and PAS core can inhibit or enhance dimerization, whereas a Tyr to Trp substitution at the Ncap-to-PAS interface stabilizes the light-state dimer. Cross-linking through engineered disulfides indicates that the light-state dimer differs considerably from the dark-state dimer found in VVD crystal structures. These results verify the role of Ncap conformational changes in gating the photic response of Neurospora crassa, and indicate that LOV:LOV homo or hetero dimerization may be a mechanism for regulating light-activated gene expression. PMID:18553928

A Latent Heat Retrieval and its Effects on the Intensity and Structure Change of Hurricane Guillermo (1997). Part I: The Algorithm and Observations.

NASA Technical Reports Server (NTRS)

Guimond, Stephen R.; Bourassa, mark A.; Reasor, Paul D.

2011-01-01

The release of latent heat in clouds is an essential part of the formation and I intensification ohurricanes. The community knows very little about the intensity and structure of latent heating due largely to inadequate observations. In this paper, a new method for retrieving the latent heating field in hurricanes from airborne Dopple radar is presented and fields from rapidly intensifying Hurricane Guillermo (1997) are shown.

Formaldehyde cross-linking and structural proteomics: Bridging the gap.

PubMed

Srinivasa, Savita; Ding, Xuan; Kast, Juergen

2015-11-01

Proteins are dynamic entities constantly moving and altering their structures based on their functions and interactions inside and outside the cell. Formaldehyde cross-linking combined with mass spectrometry can accurately capture interactions of these rapidly changing biomolecules while maintaining their physiological surroundings. Even with its numerous established uses in biology and compatibility with mass spectrometry, formaldehyde has not yet been applied in structural proteomics. However, formaldehyde cross-linking is moving toward analyzing tertiary structure, which conventional cross-linkers have already accomplished. The purpose of this review is to describe the potential of formaldehyde cross-linking in structural proteomics by highlighting its applications, characteristics and current status in the field. Copyright © 2015 Elsevier Inc. All rights reserved.

From patterns to emerging processes in mechanistic urban ecology.

PubMed

Shochat, Eyal; Warren, Paige S; Faeth, Stanley H; McIntyre, Nancy E; Hope, Diane

2006-04-01

Rapid urbanization has become an area of crucial concern in conservation owing to the radical changes in habitat structure and loss of species engendered by urban and suburban development. Here, we draw on recent mechanistic ecological studies to argue that, in addition to altered habitat structure, three major processes contribute to the patterns of reduced species diversity and elevated abundance of many species in urban environments. These activities, in turn, lead to changes in animal behavior, morphology and genetics, as well as in selection pressures on animals and plants. Thus, the key to understanding urban patterns is to balance studying processes at the individual level with an integrated examination of environmental forces at the ecosystem scale.

Quantitative NDE of Composite Structures at NASA

NASA Technical Reports Server (NTRS)

Cramer, K. Elliott; Leckey, Cara A. C.; Howell, Patricia A.; Johnston, Patrick H.; Burke, Eric R.; Zalameda, Joseph N.; Winfree, William P.; Seebo, Jeffery P.

2015-01-01

The use of composite materials continues to increase in the aerospace community due to the potential benefits of reduced weight, increased strength, and manufacturability. Ongoing work at NASA involves the use of the large-scale composite structures for spacecraft (payload shrouds, cryotanks, crew modules, etc). NASA is also working to enable the use and certification of composites in aircraft structures through the Advanced Composites Project (ACP). The rapid, in situ characterization of a wide range of the composite materials and structures has become a critical concern for the industry. In many applications it is necessary to monitor changes in these materials over a long time. The quantitative characterization of composite defects such as fiber waviness, reduced bond strength, delamination damage, and microcracking are of particular interest. The research approaches of NASA's Nondestructive Evaluation Sciences Branch include investigation of conventional, guided wave, and phase sensitive ultrasonic methods, infrared thermography and x-ray computed tomography techniques. The use of simulation tools for optimizing and developing these methods is also an active area of research. This paper will focus on current research activities related to large area NDE for rapidly characterizing aerospace composites.

Antiquity of the South Atlantic Anomaly and evidence for top-down control on the geodynamo.

PubMed

Tarduno, John A; Watkeys, Michael K; Huffman, Thomas N; Cottrell, Rory D; Blackman, Eric G; Wendt, Anna; Scribner, Cecilia A; Wagner, Courtney L

2015-07-28

The dramatic decay of dipole geomagnetic field intensity during the last 160 years coincides with changes in Southern Hemisphere (SH) field morphology and has motivated speculation of an impending reversal. Understanding these changes, however, has been limited by the lack of longer-term SH observations. Here we report the first archaeomagnetic curve from southern Africa (ca. 1000-1600 AD). Directions change relatively rapidly at ca. 1300 AD, whereas intensities drop sharply, at a rate greater than modern field changes in southern Africa, and to lower values. We propose that the recurrence of low field strengths reflects core flux expulsion promoted by the unusual core-mantle boundary (CMB) composition and structure beneath southern Africa defined by the African large low shear velocity province (LLSVP). Because the African LLSVP and CMB structure are ancient, this region may have been a steady site for flux expulsion, and triggering of geomagnetic reversals, for millions of years.

Assessment of Alphamagnetic Spectrometer (AMS) Upper Experiment Structural Configuration Shielding Effectiveness Associated with Change from Cryo-Cooled Magnet to Permanent Magnet

NASA Technical Reports Server (NTRS)

Scully, Robert

2012-01-01

In the spring of 2010, the Alpha Magnetic Spectrometer 2 (AMS-02) underwent a series of system level electromagnetic interference control measurements, followed by thermal vacuum testing. Shortly after completion of the thermal vacuum testing, the project decided to remove the cryogenically cooled superconducting magnet, and replace it with the original permanent magnet design employed in the earlier AMS- 01 assembly. Doing so necessitated several structural changes, as well as removal or modification of numerous electronic and thermal control devices and systems. At this stage, the project was rapidly approaching key milestone dates for hardware completion and delivery for launch, and had little time for additional testing or assessment of any impact to the electromagnetic signature of the AMS-02. Therefore, an analytical assessment of the radiated emissions behavioural changes associated with the system changes was requested.

A web-based rapid prototyping and clinical conversational system that complements electronic patient record system.

PubMed

Kim, J H; Ferziger, R; Kawaloff, H B; Sands, D Z; Safran, C; Slack, W V

2001-01-01

Even the most extensive hospital information system cannot support all the complex and ever-changing demands associated with a clinical database, such as providing department or personal data forms, and rating scales. Well-designed clinical dialogue programs may facilitate direct interaction of patients with their medical records. Incorporation of extensive and loosely structured clinical data into an existing medical record system is an essential step towards a comprehensive clinical information system, and can best be achieved when the practitioner and the patient directly enter the contents. We have developed a rapid prototyping and clinical conversational system that complements the electronic medical record system, with its generic data structure and standard communication interfaces based on Web technology. We believe our approach can enhance collaboration between consumer-oriented and provider-oriented information systems.

A change in climate causes rapid evolution of multiple life-history traits and their interactions in an annual plant.

PubMed

Franks, S J; Weis, A E

2008-09-01

Climate change is likely to spur rapid evolution, potentially altering integrated suites of life-history traits. We examined evolutionary change in multiple life-history traits of the annual plant Brassica rapa collected before and after a recent 5-year drought in southern California. We used a direct approach to examining evolutionary change by comparing ancestors and descendants. Collections were made from two populations varying in average soil moisture levels, and lines propagated from the collected seeds were grown in a greenhouse and experimentally subjected to conditions simulating either drought (short growing season) or high precipitation (long growing season) years. Comparing ancestors and descendants, we found that the drought caused many changes in life-history traits, including a shift to earlier flowering, longer duration of flowering, reduced peak flowering and greater skew of the flowering schedule. Descendants had thinner stems and fewer leaf nodes at the time of flowering than ancestors, indicating that the drought selected for plants that flowered at a smaller size and earlier ontogenetic stage rather than selecting for plants to develop more rapidly. Thus, there was not evidence for absolute developmental constraints to flowering time evolution. Common principal component analyses showed substantial differences in the matrix of trait covariances both between short and long growing season treatments and between populations. Although the covariances matrices were generally similar between ancestors and descendants, there was evidence for complex evolutionary changes in the relationships among the traits, and these changes depended on the population and treatment. These results show that a full appreciation of the impacts of global change on phenotypic evolution will entail an understanding of how changes in climatic conditions affect trait values and the structure of relationships among traits.

3D printing in chemical engineering and catalytic technology: structured catalysts, mixers and reactors.

PubMed

Parra-Cabrera, Cesar; Achille, Clement; Kuhn, Simon; Ameloot, Rob

2018-01-02

Computer-aided fabrication technologies combined with simulation and data processing approaches are changing our way of manufacturing and designing functional objects. Also in the field of catalytic technology and chemical engineering the impact of additive manufacturing, also referred to as 3D printing, is steadily increasing thanks to a rapidly decreasing equipment threshold. Although still in an early stage, the rapid and seamless transition between digital data and physical objects enabled by these fabrication tools will benefit both research and manufacture of reactors and structured catalysts. Additive manufacturing closes the gap between theory and experiment, by enabling accurate fabrication of geometries optimized through computational fluid dynamics and the experimental evaluation of their properties. This review highlights the research using 3D printing and computational modeling as digital tools for the design and fabrication of reactors and structured catalysts. The goal of this contribution is to stimulate interactions at the crossroads of chemistry and materials science on the one hand and digital fabrication and computational modeling on the other.

Coevolution of cooperation and network structure under natural selection

NASA Astrophysics Data System (ADS)

Yang, D.-P.; Lin, H.; Shuai, J. W.

2011-02-01

A coevolution model by coupling mortality and fertility selection is introduced to investigate the evolution of cooperation and network structure in the prisoner's dilemma game. The cooperation level goes through a continuous phase transition vs. defection temptation b for low mortality selection intensity β and through a discontinuous one for infinite β. The cooperation level is enhanced most at β≈1 for any b. The local and global properties of the network structure, such as cluster and cooperating k-core, are investigated for the understanding of cooperation evolution. Cooperation is promoted by forming a tight cooperating k-core at moderate β, but too large β will destroy the cooperating k-core rapidly resulting in a rapid drop of the cooperation level. Importantly, the infinite β changes the normalized sucker's payoff S from 0 to 1-b and its dynamics of the cooperation level undergoes a very slow power-law decay, which leads the evolution into the regime of neutral evolution.

Understanding changes in the UK's CO2 emissions: a global perspective.

PubMed

Baiocchi, Giovanni; Minx, Jan C

2010-02-15

The UK appears to be a leading country in curbing greenhouse gas (GHG) emissions. Unlike many other developed countries, it has already met its Kyoto obligations and defined ambitious, legally binding targets for the future. Recently this achievement has been called into question as it ignores rapidly changing patterns of production and international trade. We use structural decomposition analysis (SDA) to investigate the drivers behind annual changes in CO(2) emission from consumption in the UK between 1992 and 2004. In contrast with previous SDA-based studies, we apply the decomposition to a global, multiregional input-output model (MRIO), which accounts for UK imports from all regions and uses region-specific production structures and CO(2) intensities. We find that improvements from "domestic" changes in efficiency and production structure led to a 148 Mt reduction in CO(2) emissions, which only partially offsets emission increases of 217 Mt from changes in the global supply chain and from growing consumer demand. Recent emission reductions achieved in the UK are not merely a reflection of a greening of the domestic supply chain, but also of a change in the international division of labor in the global production of goods and services.

Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hura, Greg L.; Menon, Angeli L.; Hammel, Michal

2009-07-20

We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes formore » 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.« less

A Skills beyond School Review of Peru. OECD Reviews of Vocational Education and Training

ERIC Educational Resources Information Center

McCarthy, Mary Alice; Musset, Pauline

2016-01-01

Vocational education and training (VET) programmes are facing rapid change and intensifying challenges. How can employers and unions be engaged? How can workbased learning be used? How can teachers and trainers be effectively prepared? How should postsecondary programmes be structured? The country reports in this series look at these and other…

Course Evaluation Matters: Improving Students' Learning Experiences with a Peer-Assisted Teaching Programme

ERIC Educational Resources Information Center

Carbone, Angela; Ross, Bella; Phelan, Liam; Lindsay, Katherine; Drew, Steve; Stoney, Sue; Cottman, Caroline

2015-01-01

In the rapidly changing global higher education sector, greater attention is being paid to the quality of university teaching. However, academics have traditionally not received formal teacher training. The peer-assisted teaching programme reported on in this paper provides a structured yet flexible approach for peers to assist each other in…

Canonical Correlation Analysis on Life Stress and Learning Burnout of College Students in Taiwan

ERIC Educational Resources Information Center

Huang, Yun-Chen; Lin, Shu Hui

2010-01-01

With rapid social changes, stress in life has increased significantly for everyone including college students. Understanding life stress among college students and how it may affect learning burnout has become an important concern for education researchers. The purposes of this study were (1) to assess the current status and factor structures of…

Continuous Professional Development: What Role and Who Benefits? Reflections on Teacher Development in Uganda

ERIC Educational Resources Information Center

Wabule, Alice

2016-01-01

Continuous professional development has assumed a central role in organisational development in recent years. In the teaching profession, initial training is no longer seen as enough due to rapid changes in technology, social structures, ideologies and the increasing diversity of the classrooms. While acknowledging the empowering aspect of CPD,…

Physics Teacher Candidates' Opinions on Fiber Optics and New Technologies in This Field

ERIC Educational Resources Information Center

Çildir, Sema

2016-01-01

Factors such as innovations brought in by the developing technology, also rapidly changing social structures casted various roles to both the student and the teacher. Therefore, it is necessary to associate such knowledge acquired in courses with implications of the knowledge in our real lives and to constantly enrich course contents, namely to…

Aspirations of and Realities for Hong Kong Students: Is the "Formal" Transition System Effective?

ERIC Educational Resources Information Center

Pavlova, Margarita

2017-01-01

School to work transition is an important aspect of lifelong learning that has increased in significance as the knowledge-based economy takes off in developed countries. Rapid structural economic changes, the importance of innovation, and a shorter lifecycle of products require education systems to adjust to the needs of economies and individuals.…

A Computer Lab Exploring Evolutionary Aspects of Chromatin Structure and Dynamics for an Undergraduate Chromatin Course

ERIC Educational Resources Information Center

Eirin-Lopez, Jose M.

2013-01-01

The study of chromatin constitutes one of the most active research fields in life sciences, being subject to constant revisions that continuously redefine the state of the art in its knowledge. As every other rapidly changing field, chromatin biology requires clear and straightforward educational strategies able to efficiently translate such a…

Cordilleran forest scaling dynamics and disturbance regimes quantified by aerial LiDAR

Treesearch

Tyson L. Swetnam

2013-01-01

Semi-arid forests are in a period of rapid transition as a result of unprecedented landscape scale fires, insect outbreaks, drought, and anthropogenic land use practices. Understanding how historically episodic disturbances led to coherent forest structural and spatial patterns that promoted resilience and resistance is a critical part of addressing change. Here my...

Global Report on Adult Learning and Education

ERIC Educational Resources Information Center

Chisholm, Lynne, Ed.; Hasan, Abrar, Ed.

2010-01-01

In the 21st century, the rapid pace and complexity of economic, technological and cultural changes require women and men to adapt and re-adapt throughout their lives--all the more so in the context of globalisation. In this era of the knowledge society--where production structure is shifting towards greater knowledge use and away from reliance on…

Teacher Quality and School Improvement: What Is the Role of Research?

ERIC Educational Resources Information Center

Mincu, Monica Elena

2015-01-01

In a rapidly changing world, students' success depends upon the schools' capacity to deal with their specific instructional needs. Thus, effective teaching plays the role of a unique protective factor that may reduce and even close the achievement gap. Two broad questions structure this study: What is the research contribution to teacher quality…

Teacher Unionism in the 1980s: Four Perspectives. Australian Education Review No. 24.

ERIC Educational Resources Information Center

Spaull, Andrew; And Others

This monograph by four authors examines the structure and role of teacher unions in the three Australian states of New South Wales, Victoria, and South Australia, and analyzes the rapidly changing shape of teacher unionism at the federal level. After an introduction by Andrew Spaull, Robert White, in chapter 2, examines developments within the…

6th, 7th and 8th Graders' Attitudes towards Online Homework Assignment Sites

ERIC Educational Resources Information Center

Altun, Eralp

2008-01-01

This study has pedagogical implications in view of rapidly growing technological development and widespread use of the Internet in instruction. The spread of online homework sites with highly commercial aims has opened a new research area regarding the structure, aim and the significant role of homework in education. Particularly, the changes in…

Regional patterns of major nonnative invasive plants and associated factors in upper Midwest forests

Treesearch

Zhaofei Fan; W. Keith Moser; Mark H. Hansen; Mark D. Nelson

2013-01-01

Nonnative invasive plants (IPs) are rapidly spreading into natural ecosystems (e.g., forests and grasslands). Potential threats of IP invasion into natural ecosystems include biodiversity loss, structural and environmental change, habitat degradation, and economic losses. The Upper Midwest of the United States encompasses the states of Illinois, Indiana, Iowa, Michigan...

Choices and Challenges: A Qualitative Exploration of Professional Women's Career Patterns

ERIC Educational Resources Information Center

Whitmarsh, Lona; Brown, Donalee; Cooper, Jane; Hawkins-Rodgers, Yolanda; Wentworth, Diane Keyser

2007-01-01

With the rapid changes occurring in the role of work in women's lives, this research project was designed to examine the career planning, career decision making, and work history of women in both female-dominated and gender-neutral careers (U.S. Department of Labor, n.d.-a). A qualitative analysis of structured interviews identified 6 emerging…

Using business intelligence to improve performance.

PubMed

Wadsworth, Tom; Graves, Brian; Glass, Steve; Harrison, A Marc; Donovan, Chris; Proctor, Andrew

2009-10-01

Cleveland Clinic's enterprise performance management program offers proof that comparisons of actual performance against strategic objectives can enable healthcare organization to achieve rapid organizational change. Here are four lessons Cleveland Clinic learned from this initiative: Align performance metrics with strategic initiatives. Structure dashboards for the CEO. Link performance to annual reviews. Customize dashboard views to the specific user.

Modelling Complexity: Making Sense of Leadership Issues in 14-19 Education

ERIC Educational Resources Information Center

Briggs, Ann R. J.

2008-01-01

Modelling of statistical data is a well established analytical strategy. Statistical data can be modelled to represent, and thereby predict, the forces acting upon a structure or system. For the rapidly changing systems in the world of education, modelling enables the researcher to understand, to predict and to enable decisions to be based upon…

Structural changes in the vascular bundles of light-exposed and shaded spruce needles suffering from Mg deficiency and ozone pollution.

PubMed

Boxler-Baldoma, Carmen; Lütz, Cornelius; Heumann, Hans-Günther; Siefermann-Harms, Dorothea

2006-02-01

The correlation between structural changes of the vascular bundles and needle yellowing was examined for needles of damaged spruce (Picea abies (L.) Karst.) growing at a Mg-deficient and ozone polluted mountain site in the Central Black Forest (840m a.s.l.). In the previous year's sun-exposed needles, the following sequence of events was observed: (1) rapid needle yellowing, (2) hypertrophy and anomalous divisions of cambium cells, (3) phloem collapse, and, (4) production of atypical xylem tracheids. Under defined shade (reduction of the photosynthetically active photon flux density of the ambient light by 85-90%), the needles remained green, while the phloem collapsed completely within the first 6 weeks of shading; subsequently, a reversal of the collapse was observed. Under both light conditions, the content of Mg not bound to chlorophyll (Mg(free)) was in the range of 0.1 mg g(-1) needle dry matter, and hardly changed throughout the investigation period. After Mg fertilization, the Mg(free) level of the previous year's needles increased to 0.2 mg g(-1) dry matter, the light-exposed needles remained green, and the vascular bundles developed no anomalies. The data show that the rapid needle yellowing of ozone-exposed Mg-deficient needles did not depend on the collapse of the phloem. Mg deficiency played a key role in the development of anomalous vascular bundles under light, and also appears to explain the transient changes in sieve cell structure under shade. The role of Mg deficiency, rather than ozone pollution, in the damage of the sieve cells was confirmed in a long-term ozone exposure experiment with young clonal spruce growing under defined conditions.

Experimental sulfate amendment alters peatland bacterial community structure.

PubMed

Strickman, R J S; Fulthorpe, R R; Coleman Wasik, J K; Engstrom, D R; Mitchell, C P J

2016-10-01

As part of a long-term, peatland-scale sulfate addition experiment, the impact of varying sulfate deposition on bacterial community responses was assessed using 16S tag encoded pyrosequencing. In three separate areas of the peatland, sulfate manipulations included an eight year quadrupling of atmospheric sulfate deposition (experimental), a 3-year recovery to background deposition following 5years of elevated deposition (recovery), and a control area. Peat concentrations of methylmercury (MeHg), a bioaccumulative neurotoxin, were measured, the production of which is attributable to a growing list of microorganisms, including many sulfate-reducing Deltaproteobacteria. The total bacterial and Deltaproteobacterial community structures in the experimental treatment differed significantly from those in the control and recovery treatments that were either indistinguishable or very similar to one another. Notably, the relatively rapid return (within three years) of bacterial community structure in the recovery treatment to a state similar to the control, demonstrates significant resilience of the peatland bacterial community to changes in atmospheric sulfate deposition. Changes in MeHg accumulation between sulfate treatments correlated with changes in the Deltaproteobacterial community, suggesting that sulfate may affect MeHg production through changes in the community structure of this group. Copyright © 2016 Elsevier B.V. All rights reserved.

Structure of the torque ring of the flagellar motor and the molecular basis for rotational switching.

PubMed

Lee, Lawrence K; Ginsburg, Michael A; Crovace, Claudia; Donohoe, Mhairi; Stock, Daniela

2010-08-19

The flagellar motor drives the rotation of flagellar filaments at hundreds of revolutions per second, efficiently propelling bacteria through viscous media. The motor uses the potential energy from an electrochemical gradient of cations across the cytoplasmic membrane to generate torque. A rapid switch from anticlockwise to clockwise rotation determines whether a bacterium runs smoothly forward or tumbles to change its trajectory. A protein called FliG forms a ring in the rotor of the flagellar motor that is involved in the generation of torque through an interaction with the cation-channel-forming stator subunit MotA. FliG has been suggested to adopt distinct conformations that induce switching but these structural changes and the molecular mechanism of switching are unknown. Here we report the molecular structure of the full-length FliG protein, identify conformational changes that are involved in rotational switching and uncover the structural basis for the formation of the FliG torque ring. This allows us to propose a model of the complete ring and switching mechanism in which conformational changes in FliG reverse the electrostatic charges involved in torque generation.

A new rapid kindling variant for induction of cortical epileptogenesis in freely moving rats

PubMed Central

Morales, Juan Carlos; Álvarez-Ferradas, Carla; Roncagliolo, Manuel; Fuenzalida, Marco; Wellmann, Mario; Nualart, Francisco Javier; Bonansco, Christian

2014-01-01

Kindling, one of the most used models of experimental epilepsy is based on daily electrical stimulation in several brain structures. Unlike the classic or slow kindling protocols (SK), the rapid kindling types (RK) described until now require continuous stimulation at suprathreshold intensities applied directly to the same brain structure used for subsequent electrophysiological and immunohistochemical studies, usually the hippocampus. However, the cellular changes observed in these rapid protocols, such as astrogliosis and neuronal loss, could be due to experimental manipulation more than to epileptogenesis-related alterations. Here, we developed a new RK protocol in order to generate an improved model of temporal lobe epilepsy (TLE) which allows gradual progression of the epilepsy as well as obtaining an epileptic hippocampus, thus avoiding direct surgical manipulation and electric stimulation over this structure. This new protocol consists of basolateral amygdala (BLA) stimulation with 10 trains of biphasic pulses (10 s; 50 Hz) per day with 20 min-intervals, during 3 consecutive days, using a subconvulsive and subthreshold intensity, which guarantees tissue integrity. The progression of epileptic activity was evaluated in freely moving rats through electroencephalographic (EEG) recordings from cortex and amygdala, accompanied with synchronized video recordings. Moreover, we assessed the effectiveness of RK protocol and the establishment of epilepsy by evaluating cellular alterations of hippocampal slices from kindled rats. RK protocol induced convulsive states similar to SK protocols but in 3 days, with persistently lowered threshold to seizure induction and epileptogenic-dependent cellular changes in amygdala projection areas. We concluded that this novel RK protocol introduces a new variant of the chronic epileptogenesis models in freely moving rats, which is faster, highly reproducible and causes minimum cell damage with respect to that observed in other experimental models of epilepsy. PMID:25100948

A new rapid kindling variant for induction of cortical epileptogenesis in freely moving rats.

PubMed

Morales, Juan Carlos; Alvarez-Ferradas, Carla; Roncagliolo, Manuel; Fuenzalida, Marco; Wellmann, Mario; Nualart, Francisco Javier; Bonansco, Christian

2014-01-01

Kindling, one of the most used models of experimental epilepsy is based on daily electrical stimulation in several brain structures. Unlike the classic or slow kindling protocols (SK), the rapid kindling types (RK) described until now require continuous stimulation at suprathreshold intensities applied directly to the same brain structure used for subsequent electrophysiological and immunohistochemical studies, usually the hippocampus. However, the cellular changes observed in these rapid protocols, such as astrogliosis and neuronal loss, could be due to experimental manipulation more than to epileptogenesis-related alterations. Here, we developed a new RK protocol in order to generate an improved model of temporal lobe epilepsy (TLE) which allows gradual progression of the epilepsy as well as obtaining an epileptic hippocampus, thus avoiding direct surgical manipulation and electric stimulation over this structure. This new protocol consists of basolateral amygdala (BLA) stimulation with 10 trains of biphasic pulses (10 s; 50 Hz) per day with 20 min-intervals, during 3 consecutive days, using a subconvulsive and subthreshold intensity, which guarantees tissue integrity. The progression of epileptic activity was evaluated in freely moving rats through electroencephalographic (EEG) recordings from cortex and amygdala, accompanied with synchronized video recordings. Moreover, we assessed the effectiveness of RK protocol and the establishment of epilepsy by evaluating cellular alterations of hippocampal slices from kindled rats. RK protocol induced convulsive states similar to SK protocols but in 3 days, with persistently lowered threshold to seizure induction and epileptogenic-dependent cellular changes in amygdala projection areas. We concluded that this novel RK protocol introduces a new variant of the chronic epileptogenesis models in freely moving rats, which is faster, highly reproducible and causes minimum cell damage with respect to that observed in other experimental models of epilepsy.

Parents' perspectives of change in child physical activity & screen-viewing between Y1 (5-6) & Y4 (8-9) of primary school: implications for behaviour change.

PubMed

Jago, Russell; Solomon-Moore, Emma; Toumpakari, Zoi; Lawlor, Deborah A; Thompson, Janice L; Sebire, Simon J

2018-04-19

The aim of this study was to explore parents' responses to changes in children's physical activity and screen-time between Year 1 (5-6 years) and Year 4 (8-9 years of age) of primary school. A secondary aim was to identify how parents adapt their parenting to rapidly changing screen-based technology. Data were from the longitudinal B-Proact1v Study. Semi-structured telephone interviews were conducted between July and October 2016 with a sub-sample of 51 parents who participated in the study at Year 4. The sample was drawn from 1223 families who took part in the B-Proact1v in which the children wore an accelerometer for 5 days and mean minutes of moderate to vigorous intensity physical activity (MVPA) and sedentary minutes per day were derived. This sample was stratified according to the child's MVPA and sedentary (SED) minutes per day, and by child gender. Data were thematically analysed. Analysis yielded five main themes: 1) Parents reported how children's interests change with free play decreasing and structured activity increasing. 2) Parents highlighted how their children's independence and ability to make choices in relation to physical activity and screen-viewing increase, and that parental influence decreased, as the child gets older. 3) Parents reported that the transition from Year 1 to Year 4 appeared to be a time of substantial change in the screen-based devices that children used and the content that they viewed. 4) Parents reported that managing screen-viewing was harder compared to three years ago and a third of parents expressed concerns about the difficulty of managing screen-viewing in the future. 5) Parents reported using general principles for managing children's screen-viewing including engaging the children with rule setting and encouraging self-regulation. Parents reported that children's physical activity and sedentary screen behaviours change between Year 1 and Year 4 with children obtaining increased licence to influence the type, location and frequency with which they are active or sedentary. These changes and rapid advances in screen-viewing technology are a challenge for parents to negotiate and highlight a need to develop innovative and flexible strategies to help parents adapt to a rapidly changing environment.

Elevated Air Humidity Changes Soil Bacterial Community Structure in the Silver Birch Stand.

PubMed

Truu, Marika; Ostonen, Ivika; Preem, Jens-Konrad; Lõhmus, Krista; Nõlvak, Hiie; Ligi, Teele; Rosenvald, Katrin; Parts, Kaarin; Kupper, Priit; Truu, Jaak

2017-01-01

Soil microbes play a fundamental role in forest ecosystems and respond rapidly to changes in the environment. Simultaneously with the temperature increase the climate change scenarios also predict an intensified hydrological cycle for the Baltic Sea runoff region. The aim of this study was to assess the effect of elevated air humidity on the top soil microbial community structure of a silver birch ( Betula pendula Roth.) stand by using a free air humidity manipulation facility (FAHM). The bacterial community structures of bulk soil and birch rhizosphere were analyzed using high-throughput sequencing of bacteria-specific16S rRNA gene fragments and quantification of denitrification related genes. The increased air humidity altered both bulk soil and rhizosphere bacterial community structures, and changes in the bacterial communities initiated by elevated air humidity were related to modified soil abiotic and biotic variables. Network analysis revealed that variation in soil bacterial community structural units is explained by altered abiotic conditions such as increased pH value in bulk soil, while in rhizosphere the change in absorptive root morphology had a higher effect. Among root morphological traits, the absorptive root diameter was strongest related to the bacterial community structure. The changes in bacterial community structures under elevated air humidity are associated with shifts in C, N, and P turnover as well as mineral weathering processes in soil. Increased air humidity decreased the nir and nosZ gene abundance in the rhizosphere bacterial community. The potential contribution of the denitrification to the N 2 O emission was not affected by the elevated air humidity in birch stand soil. In addition, the study revealed a strong link between the bacterial community structure, abundance of denitrification related genes, and birch absorptive root morphology in the ecosystem system adaptation to elevated air humidity.

Elevated Air Humidity Changes Soil Bacterial Community Structure in the Silver Birch Stand

PubMed Central

Truu, Marika; Ostonen, Ivika; Preem, Jens-Konrad; Lõhmus, Krista; Nõlvak, Hiie; Ligi, Teele; Rosenvald, Katrin; Parts, Kaarin; Kupper, Priit; Truu, Jaak

2017-01-01

Soil microbes play a fundamental role in forest ecosystems and respond rapidly to changes in the environment. Simultaneously with the temperature increase the climate change scenarios also predict an intensified hydrological cycle for the Baltic Sea runoff region. The aim of this study was to assess the effect of elevated air humidity on the top soil microbial community structure of a silver birch (Betula pendula Roth.) stand by using a free air humidity manipulation facility (FAHM). The bacterial community structures of bulk soil and birch rhizosphere were analyzed using high-throughput sequencing of bacteria-specific16S rRNA gene fragments and quantification of denitrification related genes. The increased air humidity altered both bulk soil and rhizosphere bacterial community structures, and changes in the bacterial communities initiated by elevated air humidity were related to modified soil abiotic and biotic variables. Network analysis revealed that variation in soil bacterial community structural units is explained by altered abiotic conditions such as increased pH value in bulk soil, while in rhizosphere the change in absorptive root morphology had a higher effect. Among root morphological traits, the absorptive root diameter was strongest related to the bacterial community structure. The changes in bacterial community structures under elevated air humidity are associated with shifts in C, N, and P turnover as well as mineral weathering processes in soil. Increased air humidity decreased the nir and nosZ gene abundance in the rhizosphere bacterial community. The potential contribution of the denitrification to the N2O emission was not affected by the elevated air humidity in birch stand soil. In addition, the study revealed a strong link between the bacterial community structure, abundance of denitrification related genes, and birch absorptive root morphology in the ecosystem system adaptation to elevated air humidity. PMID:28421053

The reanalysis of biogeography of the Asian tree frog, Rhacophorus (Anura: Rhacophoridae): geographic shifts and climatic change influenced the dispersal process and diversification

PubMed Central

Wang, Hui; Wu, Jun; Kang, Xing; Qian, Lifu; Chen, Jinyun; Rao, Dingqi; Jiang, Jianping

2017-01-01

Rapid uplifts of the Tibetan Plateau and climate change in Asia are thought to have profoundly modulated the diversification of most of the species distributed throughout Asia. The ranoid tree frog genus Rhacophorus, the largest genus in the Rhacophoridae, is widely distributed in Asia and especially speciose in the areas south and east of the Tibetan Plateau. Here, we infer phylogenetic relationships among species and estimate divergence times, asking whether the spatiotemporal characteristics of diversification within Rhacophorus were related to rapid uplifts of the Tibetan Plateau and concomitant climate change. Phylogenetic analysis recovered distinct lineage structures in Rhacophorus, which indicated a clear distribution pattern from Southeast Asia toward East Asia and India. Molecular dating suggests that the first split within the genus date back to the Middle Oligocene (approx. 30 Ma). The Rhacophorus lineage through time (LTT) showed that there were periods of increased speciation rate: 14–12 Ma and 10–4 Ma. In addition, ancestral area reconstructions supported Southeast Asia as the ancestral area of Rhacophorus. According to the results of molecular dating, ancestral area reconstructions and LTT we think the geographic shifts, the staged rapid rises of the Tibetan Plateau with parallel climatic changes and reinforcement of the Asian monsoons (15 Ma, 8 Ma and 4–3 Ma), possibly prompted a burst of diversification in Rhacophorus. PMID:29177111

Hurricanes, coral reefs and rainforests: resistance, ruin and recovery in the Caribbean

USGS Publications Warehouse

Lugo, Ariel E.; Rogers, Caroline S.; Nixon, Scott W.

2000-01-01

The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some reefs from fully developed hurricane waves. While storms may produce dramatic local reef damage, they appear to have little impact on the ability of coral reefs to provide food or habitat for fish and other animals. Rainforests experience an enormous increase in wind energy during hurricanes with dramatic structural changes in the vegetation. The resulting changes in forest microclimate are larger than those on reefs and the loss of fruit, leaves, cover, and microclimate has a great impact on animal populations. Recovery of many aspects of rainforest structure and function is rapid, though there may be long-term changes in species composition. While resistance and repair have maintained reefs and rainforests in the past, human impacts may threaten their ability to survive.

Dynamic and Progressive Control of DNA Origami Conformation by Modulating DNA Helicity with Chemical Adducts.

PubMed

Chen, Haorong; Zhang, Hanyu; Pan, Jing; Cha, Tae-Gon; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

2016-05-24

DNA origami has received enormous attention for its ability to program complex nanostructures with a few nanometer precision. Dynamic origami structures that change conformation in response to environmental cues or external signals hold great promises in sensing and actuation at the nanoscale. The reconfiguration mechanism of existing dynamic origami structures is mostly limited to single-stranded hinges and relies almost exclusively on DNA hybridization or strand displacement. Here, we show an alternative approach by demonstrating on-demand conformation changes with DNA-binding molecules, which intercalate between base pairs and unwind DNA double helices. The unwinding effect modulates the helicity mismatch in DNA origami, which significantly influences the internal stress and the global conformation of the origami structure. We demonstrate the switching of a polymerized origami nanoribbon between different twisting states and a well-constrained torsional deformation in a monomeric origami shaft. The structural transformation is shown to be reversible, and binding isotherms confirm the reconfiguration mechanism. This approach provides a rapid and reversible means to change DNA origami conformation, which can be used for dynamic and progressive control at the nanoscale.

Temperature Dependence of the Structural Parameters in the Transformation of Aragonite to Calcite, as Determined from In Situ Synchrotron Powder X-ray-Diffratction Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antao, Sytle M.; Hassan, Ishmael; West Indies)

The temperature dependency of the crystal structure and the polymorphic transition of CaCO{sub 3} from aragonite to calcite were studied using Rietveld structure refinement and high-temperature in situ synchrotron powder X-ray-diffraction data at ambient pressure, P. The orthorhombic metastable aragonite at room P, space group Pmcn, transforms to trigonal calcite, space group R{bar 3}c, at about T{sub c} = 468 C. This transformation occurs rapidly; it starts at about 420 C and is completed by 500 C, an 80 C interval that took about 10 minutes using a heating rate of 8 C/min. Structurally, from aragonite to calcite, the distributionmore » of the Ca atom changes from approximately hexagonal to cubic close-packing. A 5.76% discontinuous increase in volume accompanies the reconstructive first-order transition. Besides the change in coordination of the Ca atom from nine to six from aragonite to calcite, the CO{sub 3} groups change by a 30{sup o} rotation across the transition.« less

Geography program, design, structure and operational strategy

NASA Technical Reports Server (NTRS)

Alexander, R. H.

1970-01-01

The geography program is designed to move systematically toward a capability to increase remote sensing data into operational systems for monitoring land use and related environmental change. The problems of environmental imbalance arising from rapid urbanization and other dramatic changes in land use are considered. These overall problems translate into working level problems of establishing the validity of various sensor-data combinations that will best obtain the regional land use and environmental information. The goal, to better understand, predict, and assist policy makers to regulate urban and regional land use changes resulting from population growth and technological advancement, is put forth.

Recent research on inherent molecular structure, physiochemical properties, and bio-functions of food and feed-type Avena sativa oats and processing-induced changes revealed with molecular microspectroscopic techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prates, Luciana Louzada; Yu, Peiqiang

Avena sativa oat is a cereal widely used as human food and livestock feed. However, the low metabolized energy and the rapid rumen degradations of protein and starch have limited the use of A. sativa oat grains. To overcome this disadvantage, new A. sativa oat varieties have been developed. Additionally, heat-related processing has been performed to decrease the degradation rate and improve the absorption of amino acids in the small intestine. The nutritive value is reflected by both chemical composition and inherent molecular structure conformation. However, the traditional wet chemical analysis is not able to detect the inherent molecular structuresmore » within an intact tissue. The advanced synchrotron-radiation and globar-based molecular microspectroscopy have been developed recently and applied to study internal molecular structures and the processing induced structure changes in A. sativa oats and reveal how molecular structure changes in relation to nutrient availability. This review aimed to obtain the recent information regarding physiochemical properties, molecular structures, metabolic characteristics of protein, and the heat-induced changes in new A. sativa oat varieties. The use of the advanced vibrational molecular spectroscopy was emphasized, synchrotron- and globar-based (micro)spectroscopy, to reveal the inherent structure of A. sativa oats at cellular and molecular levels and to reveal the heat processing effect on the degradation characteristics and the protein molecular structure in A. sativa oats. The relationship between nutrient availability and protein molecular inherent structure was also presented. Information described in this review gives better insight in the physiochemical properties, molecular structure, and the heat-induced changes in A. sativa oat detected with advanced molecular spectroscopic techniques in combinination with conventional nutrition study techniques.« less

Modulation of Small-scale Turbulence Structure by Large-scale Motions in the Absence of Direct Energy Transfer.

NASA Astrophysics Data System (ADS)

Brasseur, James G.; Juneja, Anurag

1996-11-01

Previous DNS studies indicate that small-scale structure can be directly altered through ``distant'' dynamical interactions by energetic forcing of the large scales. To remove the possibility of stimulating energy transfer between the large- and small-scale motions in these long-range interactions, we here perturb the large scale structure without altering its energy content by suddenly altering only the phases of large-scale Fourier modes. Scale-dependent changes in turbulence structure appear as a non zero difference field between two simulations from identical initial conditions of isotropic decaying turbulence, one perturbed and one unperturbed. We find that the large-scale phase perturbations leave the evolution of the energy spectrum virtually unchanged relative to the unperturbed turbulence. The difference field, on the other hand, is strongly affected by the perturbation. Most importantly, the time scale τ characterizing the change in in turbulence structure at spatial scale r shortly after initiating a change in large-scale structure decreases with decreasing turbulence scale r. Thus, structural information is transferred directly from the large- to the smallest-scale motions in the absence of direct energy transfer---a long-range effect which cannot be explained by a linear mechanism such as rapid distortion theory. * Supported by ARO grant DAAL03-92-G-0117

[Devaluation of the African Financial Community franc and the dietary strategies of families in Bamako (Mali)].

PubMed

Ag Bendech, M; Chauliac, M; Gerbouin-Rerolle, P; Kante, N; Malvy, D J

1997-01-01

This survey, conducted in 1996, evaluated changes in the way families feed themselves caused by the effects of devaluation of the CFA franc. It involved semi-directed interviews with 64 subjects from various socio-economic backgrounds (affluent, middle-class, poor). The subjects spoke of the difficulties of daily life, lack of money and rapid, unpredictable rises in the prices of essential goods caused by the devaluation. They did not understand the reasons for the devaluation, which has caused rapid changes in the social conditions and nutrition of urban families and has exacerbated the inequality of access to foodstuffs. Affluent families have adopted strategies that increase the family food budget, compensating for price increases. The meals of poor and middle-class families have been directly affected in both structure and content. Poor families have been particularly badly affected. All the changes in strategy, and substitutions of one product for another described by middle-class families were already being used by the poor families before devaluation.

Nanoscale Structural and Mechanical Analysis of Bacillus anthracis Spores Inactivated with Rapid Dry Heating

PubMed Central

Felker, Daniel L.; Burggraf, Larry W.

2014-01-01

Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142

Mapping the Dynamics of Shear Stress—Induced Structural Changes in Endothelial Cells

PubMed Central

Mott, Rosalind E.; Helmke, Brian P.

2009-01-01

Hemodynamic shear stress regulates endothelial cell biochemical processes that govern cytoskeletal contractility, focal adhesion dynamics, and extracellular matrix assembly. Since shear stress causes rapid strain focusing at discrete locations in the cytoskeleton, we hypothesized that shear stress coordinately alters structural dynamics in the cytoskeleton, focal adhesion sites, and extracellular matrix on a time scale of minutes. Using multi-wavelength 4-D fluorescence microscopy, we measured the displacement of rhodamine-fibronectin and of GFP-labeled actin, vimentin, paxillin, and/or vinculin in aortic endothelial cells before and after onset of steady unidirectional shear stress. In the cytoskeleton, the onset of shear stress increased actin polymerization into lamellipodia, altered the angle of lateral displacement of actin stress fibers and vimentin filaments, and decreased centripetal remodeling of actin stress fibers in both subconfluent and confluent cell layers. Shear stress induced the formation of new focal complexes and reduced the centripetal remodeling of focal adhesions in regions of new actin polymerization. The structural dynamics of focal adhesions and the fibronectin matrix varied with cell density. In subconfluent cell layers, shear stress onset decreased the displacement of focal adhesions and fibronectin fibrils. In confluent monolayers, the direction of fibronectin and focal adhesion displacement shifted significantly towards the downstream direction within one minute after onset of shear stress. These spatially coordinated rapid changes in the structural dynamics of cytoskeleton, focal adhesions, and extracellular matrix are consistent with focusing of mechanical stress and/or strain near major sites of shear stress-mediated mechanotransduction. PMID:17855768

Increased variability in ApcMin/+ intestinal tissue can be measured with microultrasound

NASA Astrophysics Data System (ADS)

Fatehullah, A.; Sharma, S.; Newton, I. P.; Langlands, A. J.; Lay, H.; Nelson, S. A.; McMahon, R. K.; McIlvenny, N.; Appleton, P. L.; Cochran, S.; Näthke, I. S.

2016-07-01

Altered tissue structure is a feature of many disease states and is usually measured by microscopic methods, limiting analysis to small areas. Means to rapidly and quantitatively measure the structure and organisation of large tissue areas would represent a major advance not just for research but also in the clinic. Here, changes in tissue organisation that result from heterozygosity in Apc, a precancerous situation, are comprehensively measured using microultrasound and three-dimensional high-resolution microscopy. Despite its normal appearance in conventionally examined cross-sections, both approaches revealed a significant increase in the variability of tissue organisation in Apc heterozygous tissue. These changes preceded the formation of aberrant crypt foci or adenoma. Measuring these premalignant changes using microultrasound provides a potential means to detect microscopically abnormal regions in large tissue samples, independent of visual examination or biopsies. Not only does this provide a powerful tool for studying tissue structure in experimental settings, the ability to detect and monitor tissue changes by microultrasound could be developed into a powerful adjunct to screening endoscopy in the clinic.

The Role of Phase Changes in TiO2/Pt/TiO2 Filaments

NASA Astrophysics Data System (ADS)

Bíró, Ferenc; Hajnal, Zoltán; Dücső, Csaba; Bársony, István

2018-04-01

This work analyses the role of phase changes in TiO2/Pt/TiO2 layer stacks for micro-heater application regarding their stability and reliable operation. The polycrystalline Pt layer wrapped in a TiO2 adhesion layer underwent a continuous recrystallisation in a self-heating operation causing a drift in the resistance ( R) versus temperature ( T) performance. Simultaneously, the TiO2 adhesion layer also deteriorates at high temperature by phase changes from amorphous to anatase and rutile crystallite formation, which not only influences the Pt diffusion in different migration phenomena, but also reduces the cross section of the Pt heater wire. Thorough scanning electron microscopy, energy dispersive spectroscopy, cross-sectional transmission electron microscopy (XTEM) and electron beam diffraction analysis of the structures operated at increasing temperature revealed the elemental structural processes leading to the instabilities and the accelerated degradation, resulting in rapid breakdown of the heater wire. Owing to stability and reliability criteria, the conditions for safe operation of these layer structures could be determined.

Spatio-temporal patterns of major bacterial groups in alpine waters.

PubMed

Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart E G; Robinson, Christopher T

2014-01-01

Glacial alpine landscapes are undergoing rapid transformation due to changes in climate. The loss of glacial ice mass has directly influenced hydrologic characteristics of alpine floodplains. Consequently, hyporheic sediment conditions are likely to change in the future as surface waters fed by glacial water (kryal) become groundwater dominated (krenal). Such environmental shifts may subsequently change bacterial community structure and thus potential ecosystem functioning. We quantitatively investigated the structure of major bacterial groups in glacial and groundwater-fed streams in three alpine floodplains during different hydrologic periods. Our results show the importance of several physico-chemical variables that reflect local geological characteristics as well as water source in structuring bacterial groups. For instance, Alpha-, Betaproteobacteria and Cytophaga-Flavobacteria were influenced by pH, conductivity and temperature as well as by inorganic and organic carbon compounds, whereas phosphorous compounds and nitrate showed specific influence on single bacterial groups. These results can be used to predict future bacterial group shifts, and potential ecosystem functioning, in alpine landscapes under environmental transformation.

Physicochemical structural changes of cellulosic substrates during enzymatic saccharification

DOE PAGES

Meng, Xianzhi; Yoo, Chang Geun; Li, Mi; ...

2016-12-30

Enzymatic hydrolysis represents one of the major steps and barriers in the commercialization process of converting cellulosic substrates into biofuels and other value added products. It is usually achieved by a synergistic action of enzyme mixture typically consisting of multiple enzymes such as glucanase, cellobiohydrolase and β-glucosidase with different mode of actions. Due to the innate biomass recalcitrance, enzymatic hydrolysis normally starts with an initial fast rate of hydrolysis followed by a rapid decrease of rate toward the end of hydrolysis. With majority of literature studies focusing on the effect of key substrate characteristics on the initial rate or finalmore » yield of enzymatic hydrolysis, information about physicochemical structural changes of cellulosic substrates during enzymatic hydrolysis is still quite limited. Consequently, what slows down the reaction rate toward the end of hydrolysis is not well understood. Lastly, this review highlights recent advances in understanding the structural changes of cellulosic substrates during the hydrolysis process, to better understand the fundamental mechanisms of enzymatic hydrolysis.« less

Modeling structure and resilience of the dark network.

PubMed

De Domenico, Manlio; Arenas, Alex

2017-02-01

While the statistical and resilience properties of the Internet are no longer changing significantly across time, the Darknet, a network devoted to keep anonymous its traffic, still experiences rapid changes to improve the security of its users. Here we study the structure of the Darknet and find that its topology is rather peculiar, being characterized by a nonhomogeneous distribution of connections, typical of scale-free networks; very short path lengths and high clustering, typical of small-world networks; and lack of a core of highly connected nodes. We propose a model to reproduce such features, demonstrating that the mechanisms used to improve cybersecurity are responsible for the observed topology. Unexpectedly, we reveal that its peculiar structure makes the Darknet much more resilient than the Internet (used as a benchmark for comparison at a descriptive level) to random failures, targeted attacks, and cascade failures, as a result of adaptive changes in response to the attempts of dismantling the network across time.

Physicochemical structural changes of cellulosic substrates during enzymatic saccharification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Xianzhi; Yoo, Chang Geun; Li, Mi

Enzymatic hydrolysis represents one of the major steps and barriers in the commercialization process of converting cellulosic substrates into biofuels and other value added products. It is usually achieved by a synergistic action of enzyme mixture typically consisting of multiple enzymes such as glucanase, cellobiohydrolase and β-glucosidase with different mode of actions. Due to the innate biomass recalcitrance, enzymatic hydrolysis normally starts with an initial fast rate of hydrolysis followed by a rapid decrease of rate toward the end of hydrolysis. With majority of literature studies focusing on the effect of key substrate characteristics on the initial rate or finalmore » yield of enzymatic hydrolysis, information about physicochemical structural changes of cellulosic substrates during enzymatic hydrolysis is still quite limited. Consequently, what slows down the reaction rate toward the end of hydrolysis is not well understood. Lastly, this review highlights recent advances in understanding the structural changes of cellulosic substrates during the hydrolysis process, to better understand the fundamental mechanisms of enzymatic hydrolysis.« less

Modeling structure and resilience of the dark network

NASA Astrophysics Data System (ADS)

De Domenico, Manlio; Arenas, Alex

2017-02-01

While the statistical and resilience properties of the Internet are no longer changing significantly across time, the Darknet, a network devoted to keep anonymous its traffic, still experiences rapid changes to improve the security of its users. Here we study the structure of the Darknet and find that its topology is rather peculiar, being characterized by a nonhomogeneous distribution of connections, typical of scale-free networks; very short path lengths and high clustering, typical of small-world networks; and lack of a core of highly connected nodes. We propose a model to reproduce such features, demonstrating that the mechanisms used to improve cybersecurity are responsible for the observed topology. Unexpectedly, we reveal that its peculiar structure makes the Darknet much more resilient than the Internet (used as a benchmark for comparison at a descriptive level) to random failures, targeted attacks, and cascade failures, as a result of adaptive changes in response to the attempts of dismantling the network across time.

Structural insights into the evolution of a sexy protein: novel topology and restricted backbone flexibility in a hypervariable pheromone from the red-legged salamander, Plethodon shermani.

PubMed

Wilburn, Damien B; Bowen, Kathleen E; Doty, Kari A; Arumugam, Sengodagounder; Lane, Andrew N; Feldhoff, Pamela W; Feldhoff, Richard C

2014-01-01

In response to pervasive sexual selection, protein sex pheromones often display rapid mutation and accelerated evolution of corresponding gene sequences. For proteins, the general dogma is that structure is maintained even as sequence or function may rapidly change. This phenomenon is well exemplified by the three-finger protein (TFP) superfamily: a diverse class of vertebrate proteins co-opted for many biological functions - such as components of snake venoms, regulators of the complement system, and coordinators of amphibian limb regeneration. All of the >200 structurally characterized TFPs adopt the namesake "three-finger" topology. In male red-legged salamanders, the TFP pheromone Plethodontid Modulating Factor (PMF) is a hypervariable protein such that, through extensive gene duplication and pervasive sexual selection, individual male salamanders express more than 30 unique isoforms. However, it remained unclear how this accelerated evolution affected the protein structure of PMF. Using LC/MS-MS and multidimensional NMR, we report the 3D structure of the most abundant PMF isoform, PMF-G. The high resolution structural ensemble revealed a highly modified TFP structure, including a unique disulfide bonding pattern and loss of secondary structure, that define a novel protein topology with greater backbone flexibility in the third peptide finger. Sequence comparison, models of molecular evolution, and homology modeling together support that this flexible third finger is the most rapidly evolving segment of PMF. Combined with PMF sequence hypervariability, this structural flexibility may enhance the plasticity of PMF as a chemical signal by permitting potentially thousands of structural conformers. We propose that the flexible third finger plays a critical role in PMF:receptor interactions. As female receptors co-evolve, this flexibility may allow PMF to still bind its receptor(s) without the immediate need for complementary mutations. Consequently, this unique adaptation may establish new paradigms for how receptor:ligand pairs co-evolve, in particular with respect to sexual conflict.

Complementary MS Methods Assist Conformational Characterization of Antibodies with Altered S-S Bonding Networks

NASA Astrophysics Data System (ADS)

Jones, Lisa M.; Zhang, Hao; Cui, Weidong; Kumar, Sandeep; Sperry, Justin B.; Carroll, James A.; Gross, Michael L.

2013-06-01

As therapeutic monoclonal antibodies (mAbs) become a major focus in biotechnology and a source of the next-generation drugs, new analytical methods or combination methods are needed for monitoring changes in higher order structure and effects of post-translational modifications. The complexity of these molecules and their vulnerability to structural change provide a serious challenge. We describe here the use of complementary mass spectrometry methods that not only characterize mutant mAbs but also may provide a general framework for characterizing higher order structure of other protein therapeutics and biosimilars. To frame the challenge, we selected members of the IgG2 subclass that have distinct disulfide isomeric structures as a model to evaluate an overall approach that uses ion mobility, top-down MS sequencing, and protein footprinting in the form of fast photochemical oxidation of proteins (FPOP). These three methods are rapid, sensitive, respond to subtle changes in conformation of Cys → Ser mutants of an IgG2, each representing a single disulfide isoform, and may be used in series to probe higher order structure. The outcome suggests that this approach of using various methods in combination can assist the development and quality control of protein therapeutics.

Current status of the East Sea Ecosystem in a changing world

NASA Astrophysics Data System (ADS)

Lee, Sang Heon; Kang, Chang-Keun; Lee, Chung IL; Kwak, Jung Hyun

2017-12-01

The East/Japan Sea (hereafter the East Sea) is changing quickly. Warming and structural changes in the East Sea have been reported by CREAMS, an acronym of ″Circulation Research of the East Asian Marginal Seas″, which began in 1993 as an international research program to understand the water mass structure and circulation in the East Sea (Kim and Kim, 1996; Kim, 1997; Kim et al., 2001, 2002). A subsequent research program of the EAST-I, an acronym of ″the East Asian Seas Time-series″, was launched by PICES (North Pacific Marine Science Organization) and financially supported by the Korean government, allowing us to deepen our knowledge about rapidly changing processes in the East Sea (Chang et al., 2010). Although there has been considerable progress in developing a mechanistic understanding of the East Sea ecosystem responses to disturbances, more comprehensive studies are needed to address the impacts of the frequency and intensity of disturbances on marine ecosystems. The most important question of the research has been: how do environmental changes affect structural and functional biodiversity? Recently launched research on ″Long-term change of structure and function in marine ecosystems of Korea″, which has been supported by the Korean government since 2011, has given an unprecedented insight into the ecosystem dynamics in the East Sea. It therefore seems an appropriate time to devote a special issue to the topic of ″Current status of the East Sea ecosystem in a changing world″.

Examining land-use/land-cover change in the Lake Dianchi watershed of the Yunnan-Guizhou Plateau of Southwest China with remote sensing and GIS techniques: 1974–2008.

PubMed

Zhao, Yaolong; Zhang, Ke; Fu, Yingchun; Zhang, Hong

2012-10-24

Monitoring land-use/land-cover change (LULCC) and exploring its mechanisms are important processes in the environmental management of a lake watershed. The purpose of this study was to examine the spatiotemporal pattern of LULCC by using multi landscape metrics in the Lake Dianchi watershed, which is located in the Yunnan-Guizhou Plateau of Southwest China. Landsat images from the years 1974, 1988, 1998, and 2008 were analyzed using geographical information system (GIS) techniques. The results reveal that land-use/land-cover has changed greatly in the watershed since 1974. This change in land use structure was embodied in the rapid increase of developed areas with a relative change rate of up to 324.4%. The increase in developed areas mainly occurred in agricultural land, especially near the shores of Lake Dianchi. The spatial pattern and structure of the change was influenced by the urban sprawl of the city of Kunming. The urban sprawl took on the typical expansion mode of cyclic structures and a jigsaw pattern and expanded to the shore of Lake Dianchi. Agricultural land changed little with respect to the structure but changed greatly in the spatial pattern. The landscape in the watershed showed a trend of fragmentation with a complex boundary. The dynamics of land-use/land-cover in the watershed correlate with land-use policies and economic development in China.

Examining Land-Use/Land-Cover Change in the Lake Dianchi Watershed of the Yunnan-Guizhou Plateau of Southwest China with Remote Sensing and GIS Techniques: 1974-2008

PubMed Central

Zhao, Yaolong; Zhang, Ke; Fu, Yingchun; Zhang, Hong

2012-01-01

Monitoring land-use/land-cover change (LULCC) and exploring its mechanisms are important processes in the environmental management of a lake watershed. The purpose of this study was to examine the spatiotemporal pattern of LULCC by using multi landscape metrics in the Lake Dianchi watershed, which is located in the Yunnan-Guizhou Plateau of Southwest China. Landsat images from the years 1974, 1988, 1998, and 2008 were analyzed using geographical information system (GIS) techniques. The results reveal that land-use/land-cover has changed greatly in the watershed since 1974. This change in land use structure was embodied in the rapid increase of developed areas with a relative change rate of up to 324.4%. The increase in developed areas mainly occurred in agricultural land, especially near the shores of Lake Dianchi. The spatial pattern and structure of the change was influenced by the urban sprawl of the city of Kunming. The urban sprawl took on the typical expansion mode of cyclic structures and a jigsaw pattern and expanded to the shore of Lake Dianchi. Agricultural land changed little with respect to the structure but changed greatly in the spatial pattern. The landscape in the watershed showed a trend of fragmentation with a complex boundary. The dynamics of land-use/land-cover in the watershed correlate with land-use policies and economic development in China. PMID:23202820

Conservation of forest birds: evidence of a shifting baseline in community structure.

PubMed

Rittenhouse, Chadwick D; Pidgeon, Anna M; Albright, Thomas P; Culbert, Patrick D; Clayton, Murray K; Flather, Curtis H; Huang, Chengquan; Masek, Jeffrey G; Stewart, Susan I; Radeloff, Volker C

2010-08-02

Quantifying changes in forest bird diversity is an essential task for developing effective conservation actions. When subtle changes in diversity accumulate over time, annual comparisons may offer an incomplete perspective of changes in diversity. In this case, progressive change, the comparison of changes in diversity from a baseline condition, may offer greater insight because changes in diversity are assessed over longer periods of times. Our objectives were to determine how forest bird diversity has changed over time and whether those changes were associated with forest disturbance. We used North American Breeding Bird Survey data, a time series of Landsat images classified with respect to land cover change, and mixed-effects models to associate changes in forest bird community structure with forest disturbance, latitude, and longitude in the conterminous United States for the years 1985 to 2006. We document a significant divergence from the baseline structure for all birds of similar migratory habit and nest location, and all forest birds as a group from 1985 to 2006. Unexpectedly, decreases in progressive similarity resulted from small changes in richness (<1 species per route for the 22-year study period) and modest losses in abundance (-28.7 - -10.2 individuals per route) that varied by migratory habit and nest location. Forest disturbance increased progressive similarity for Neotropical migrants, permanent residents, ground nesting, and cavity nesting species. We also documented highest progressive similarity in the eastern United States. Contemporary forest bird community structure is changing rapidly over a relatively short period of time (e.g., approximately 22 years). Forest disturbance and forest regeneration are primary factors associated with contemporary forest bird community structure, longitude and latitude are secondary factors, and forest loss is a tertiary factor. Importantly, these findings suggest some regions of the United States may already fall below the habitat amount threshold where fragmentation effects become important predictors of forest bird community structure.

Characteristic Changes in Cell Surface Glycosylation Accompany Intestinal Epithelial Cell (IEC) Differentiation: High Mannose Structures Dominate the Cell Surface Glycome of Undifferentiated Enterocytes.

PubMed

Park, Dayoung; Brune, Kristin A; Mitra, Anupam; Marusina, Alina I; Maverakis, Emanual; Lebrilla, Carlito B

2015-11-01

Changes in cell surface glycosylation occur during the development and differentiation of cells and have been widely correlated with the progression of several diseases. Because of their structural diversity and sensitivity to intra- and extracellular conditions, glycans are an indispensable tool for analyzing cellular transformations. Glycans present on the surface of intestinal epithelial cells (IEC) mediate interactions with billions of native microorganisms, which continuously populate the mammalian gut. A distinct feature of IECs is that they differentiate as they migrate upwards from the crypt base to the villus tip. In this study, nano-LC/ESI QTOF MS profiling was used to characterize the changes in glycosylation that correspond to Caco-2 cell differentiation. As Caco-2 cells differentiate to form a brush border membrane, a decrease in high mannose type glycans and a concurrent increase in fucosylated and sialylated complex/hybrid type glycans were observed. At day 21, when cells appear to be completely differentiated, remodeling of the cell surface glycome ceases. Differential expression of glycans during IEC maturation appears to play a key functional role in regulating the membrane-associated hydrolases and contributes to the mucosal surface innate defense mechanisms. Developing methodologies to rapidly identify changes in IEC surface glycans may lead to a rapid screening approach for a variety of disease states affecting the GI tract. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Initial dynamic load estimates during configuration design

NASA Technical Reports Server (NTRS)

Schiff, Daniel

1987-01-01

This analysis includes the structural response to shock and vibration and evaluates the maximum deflections and material stresses and the potential for the occurrence of elastic instability, fatigue and fracture. The required computations are often performed by means of finite element analysis (FEA) computer programs in which the structure is simulated by a finite element model which may contain thousands of elements. The formulation of a finite element model can be time consuming, and substantial additional modeling effort may be necessary if the structure requires significant changes after initial analysis. Rapid methods for obtaining rough estimates of the structural response to shock and vibration are presented for the purpose of providing guidance during the initial mechanical design configuration stage.

Broadening our View of the MOC using Satellite Altimetry and Two Moored Arrays in the Atlantic: MOVE 16N and RAPID 26N

NASA Astrophysics Data System (ADS)

Duchez, A.; Frajka-Williams, E.; Lankhorst, M. J.; Koelling, J.; Send, U.

2016-02-01

The Atlantic meridional overturning circulation (MOC) carries heat northwards in the top 1000m of the Atlantic, with a deep, cold return flow below. Climate simulations predict a slowing of the AMOC in the coming years, while present day observations from boundary arrays demonstrate substantial variability on weekly- to interannual timescales. Using simultaneous observations from the MOVE 16N and RAPID 26N arrays in the Atlantic, we investigate transport and property variability. On long timescales, the tendencies in deep densities are similar between the two latitudes (towards lighter water in the west), resulting in a change in the thermal wind balance across the Atlantic. This tendency is punctuated by a more abrupt change in late 2009 at 26N and 7 months later at 16N. In situ arrays such as RAPID 26N and MOVE 16N provide detailed depth structure of transport variability, but are necessarily limited to individual latitudes. Using satellite altimetry, we show that the sea surface height (SSH) anomalies in the western half of the Atlantic covary with in situ transport estimates on interannual timescales. We use satellite altimetry to extend estimates of depth-integrated ocean transports back in time to 1993, then investigate how the spatial pattern of SSH variability broadens our view of Atlantic MOC structure beyond individual latitudes. This analysis investigates two decade+ long time series of ocean transports, and complements the findings with satellite observations.

Surface-enhanced Raman spectroscopy study on the structure changes of 4-Mercaptophenylboronic Acid under different pH conditions

NASA Astrophysics Data System (ADS)

Su, Hongyang; Wang, Yue; Yu, Zhi; Liu, Yawen; Zhang, Xiaolei; Wang, Xiaolei; Sui, Huimin; Sun, Chengbin; Zhao, Bing

2017-10-01

4-Mercaptophenylboronic Acid (4-MPBA) plays pivotal role in various fields. The orientation and existing form of the 4-MPBA strongly depend on the pH value of the media. The general aim of this work is to obtain information about the structure changes of 4-MPBA absorbed on Ag nanoparticles in different pH environment. Surface-enhanced Raman spectroscopy (SERS) technique is a simple and rapid method to study adsorption phenomena at molecule level. The investigation is done by means of SERS. In order to interpret the experimental information, a series of SERS spectra is carried out. The relative intensities of the totally symmetric (a1 mode) and non-totally symmetric (b2 mode) bands in the SERS spectra of 4-MPBA change depend on the environmental pH values, which is a manifestation of charge transfer (CT) processes. The degree of charge transfer increases with the pH value of the media changing from acidity to alkalinity. The structure changes of MPBA had been carried out in different pH environment. We envision that this approach will be of great significance in related fields of 4-MPBA-involved detection.

Full-time response of starch subjected to microwave heating.

PubMed

Fan, Daming; Wang, Liyun; Zhang, Nana; Xiong, Lei; Huang, Luelue; Zhao, Jianxin; Wang, Mingfu; Zhang, Hao

2017-06-21

The effect of non-ionizing microwave radiation on starch is due to a gelatinization temperature range that changes starch structure and properties. However, the changes in starch upon microwave heating are observable throughout the heating process. We compared the effects on starch heating by microwaves to the effects by rapid and regular conventional heating. Our results show that microwave heating promotes the rapid rearrangement of starch molecules at low temperatures; starch showed a stable dielectric response and a high dielectric constant. Microwave heating changed the Cole-Cole curve and the polarization of starch suspension at low temperatures. A marked transition at 2.45 GHz resulted in a double-polarization phenomenon. At temperatures below gelatinization, microwave-induced dielectric rearrangement and changes in the polarization characteristics of starch suspensions reduced the absorption properties; at temperatures above gelatinization, these characteristics became consistent with conventional heating. Throughout the heating process, microwaves change the electrical response and polarization characteristics of the starch at low temperatures, but on the macro level, there is no enhancement of the material's microwave absorption properties. In contrast, with the warming process, the starch exhibited a "blocking effect", and the absorption properties of the starch quickly returned to the level observed in conductive heating after gelatinization.

Osmotic Challenge Drives Rapid and Reversible Chromatin Condensation in Chondrocytes

PubMed Central

Irianto, Jerome; Swift, Joe; Martins, Rui P.; McPhail, Graham D.; Knight, Martin M.; Discher, Dennis E.; Lee, David A.

2013-01-01

Changes in extracellular osmolality have been shown to alter gene expression patterns and metabolic activity of various cell types, including chondrocytes. However, mechanisms by which physiological or pathological changes in osmolality impact chondrocyte function remain unclear. Here we use quantitative image analysis, electron microscopy, and a DNase I assay to show that hyperosmotic conditions (>400 mOsm/kg) induce chromatin condensation, while hypoosmotic conditions (100 mOsm/kg) cause decondensation. Large density changes (p < 0.001) occur over a very narrow range of physiological osmolalities, which suggests that chondrocytes likely experience chromatin condensation and decondensation during a daily loading cycle. The effect of changes in osmolality on nuclear morphology (p < 0.01) and chromatin condensation (p < 0.001) also differed between chondrocytes in monolayer culture and three-dimensional agarose, suggesting a role for cell adhesion. The relationship between condensation and osmolality was accurately modeled by a polymer gel model which, along with the rapid nature of the chromatin condensation (<20 s), reveals the basic physicochemical nature of the process. Alterations in chromatin structure are expected to influence gene expression and thereby regulate chondrocyte activity in response to osmotic changes. PMID:23442954

Efficient Flame Detection and Early Warning Sensors on Combustible Materials Using Hierarchical Graphene Oxide/Silicone Coatings.

PubMed

Wu, Qian; Gong, Li-Xiu; Li, Yang; Cao, Cheng-Fei; Tang, Long-Cheng; Wu, Lianbin; Zhao, Li; Zhang, Guo-Dong; Li, Shi-Neng; Gao, Jiefeng; Li, Yongjin; Mai, Yiu-Wing

2018-01-23

Design and development of smart sensors for rapid flame detection in postcombustion and early fire warning in precombustion situations are critically needed to improve the fire safety of combustible materials in many applications. Herein, we describe the fabrication of hierarchical coatings created by assembling a multilayered graphene oxide (GO)/silicone structure onto different combustible substrate materials. The resulting coatings exhibit distinct temperature-responsive electrical resistance change as efficient early warning sensors for detecting abnormal high environmental temperature, thus enabling fire prevention below the ignition temperature of combustible materials. After encountering a flame attack, we demonstrate extremely rapid flame detection response in 2-3 s and excellent flame self-extinguishing retardancy for the multilayered GO/silicone structure that can be synergistically transformed to a multiscale graphene/nanosilica protection layer. The hierarchical coatings developed are promising for fire prevention and protection applications in various critical fire risk and related perilous circumstances.

Zircon growth in shear zones

NASA Astrophysics Data System (ADS)

Kaulina, Tatiana

2013-04-01

The possibility of direct dating of the deformation process is critical for understanding of orogenic belts evolution. Establishing the age of deformation by isotopic methods is indispensable in the case of uneven deformation overlapping, when later deformation inherits the structural plan of the early strains, and to distinguish them on the basis of the structural data only is impossible. A good example of zircon from the shear zones is zircon formed under the eclogite facies conditions. On the one hand, the composition of zircon speaks about its formation simultaneously to eclogitic paragenesis (Rubatto, Herman, 1999; Rubatto et al., 2003). On the other hand, geological studies show that mineral reactions of eclogitization are often held only in areas of shear deformations, which provides access of fluid to the rocks (Austrheim, 1987; Jamtveit et al., 2000; Bingen et al., 2004). Zircons from mafic and ultramafic rocks of the Tanaelv and Kolvitsa belts (Kola Peninsula, the Baltic Shield) have showed that the metamorphic zircon growth is probably controlled by the metamorphic fluid regime, as evidenced by an increase of zircon quantity with the degree of shearing. The internal structure of zircon crystals can provide an evidence of zircon growth synchronous with shearing. The studied crystals have a sector zoning and often specific "patchy" zoning (Fig. 1), which speaks about rapid change of growth conditions. Such internal structure can be compared with the "snowball" garnet structure reflecting the rotation of crystals during their growth under a shift. Rapidly changing crystallization conditions can also be associated with a small amount of fluid, where supersaturation is changing even at a constant temperature. Thus, the growth of metamorphic zircon in shear zones is more likely to occur in the fluid flow synchronous with deformation. A distinctive feature of zircons in these conditions is isometric shape and sector "patchy" zoning. The work was supported by Russian Foundation of Basic Research (project: 13-05-00035.) and the DES-6 program.

Structural Changes in Isometrically Contracting Insect Flight Muscle Trapped following a Mechanical Perturbation

PubMed Central

Wu, Shenping; Liu, Jun; Perz-Edwards, Robert J.; Tregear, Richard T.; Winkler, Hanspeter; Franzini-Armstrong, Clara; Sasaki, Hiroyuki; Goldman, Yale E.; Reedy, Michael K.; Taylor, Kenneth A.

2012-01-01

The application of rapidly applied length steps to actively contracting muscle is a classic method for synchronizing the response of myosin cross-bridges so that the average response of the ensemble can be measured. Alternatively, electron tomography (ET) is a technique that can report the structure of the individual members of the ensemble. We probed the structure of active myosin motors (cross-bridges) by applying 0.5% changes in length (either a stretch or a release) within 2 ms to isometrically contracting insect flight muscle (IFM) fibers followed after 5–6 ms by rapid freezing against a liquid helium cooled copper mirror. ET of freeze-substituted fibers, embedded and thin-sectioned, provides 3-D cross-bridge images, sorted by multivariate data analysis into ∼40 classes, distinct in average structure, population size and lattice distribution. Individual actin subunits are resolved facilitating quasi-atomic modeling of each class average to determine its binding strength (weak or strong) to actin. ∼98% of strong-binding acto-myosin attachments present after a length perturbation are confined to “target zones” of only two actin subunits located exactly midway between successive troponin complexes along each long-pitch helical repeat of actin. Significant changes in the types, distribution and structure of actin-myosin attachments occurred in a manner consistent with the mechanical transients. Most dramatic is near disappearance, after either length perturbation, of a class of weak-binding cross-bridges, attached within the target zone, that are highly likely to be precursors of strong-binding cross-bridges. These weak-binding cross-bridges were originally observed in isometrically contracting IFM. Their disappearance following a quick stretch or release can be explained by a recent kinetic model for muscle contraction, as behaviour consistent with their identification as precursors of strong-binding cross-bridges. The results provide a detailed model for contraction in IFM that may be applicable to contraction in other types of muscle. PMID:22761792

Re-Structuring of Marine Communities Exposed to Environmental Change: A Global Study on the Interactive Effects of Species and Functional Richness

PubMed Central

Wahl, Martin; Link, Heike; Alexandridis, Nicolaos; Thomason, Jeremy C.; Cifuentes, Mauricio; Costello, Mark J.; da Gama, Bernardo A. P.; Hillock, Kristina; Hobday, Alistair J.; Kaufmann, Manfred J.; Keller, Stefanie; Kraufvelin, Patrik; Krüger, Ina; Lauterbach, Lars; Antunes, Bruno L.; Molis, Markus; Nakaoka, Masahiro; Nyström, Julia; bin Radzi, Zulkamal; Stockhausen, Björn; Thiel, Martin; Vance, Thomas; Weseloh, Annika; Whittle, Mark; Wiesmann, Lisa; Wunderer, Laura; Yamakita, Takehisa; Lenz, Mark

2011-01-01

Species richness is the most commonly used but controversial biodiversity metric in studies on aspects of community stability such as structural composition or productivity. The apparent ambiguity of theoretical and experimental findings may in part be due to experimental shortcomings and/or heterogeneity of scales and methods in earlier studies. This has led to an urgent call for improved and more realistic experiments. In a series of experiments replicated at a global scale we translocated several hundred marine hard bottom communities to new environments simulating a rapid but moderate environmental change. Subsequently, we measured their rate of compositional change (re-structuring) which in the great majority of cases represented a compositional convergence towards local communities. Re-structuring is driven by mortality of community components (original species) and establishment of new species in the changed environmental context. The rate of this re-structuring was then related to various system properties. We show that availability of free substratum relates negatively while taxon richness relates positively to structural persistence (i.e., no or slow re-structuring). Thus, when faced with environmental change, taxon-rich communities retain their original composition longer than taxon-poor communities. The effect of taxon richness, however, interacts with another aspect of diversity, functional richness. Indeed, taxon richness relates positively to persistence in functionally depauperate communities, but not in functionally diverse communities. The interaction between taxonomic and functional diversity with regard to the behaviour of communities exposed to environmental stress may help understand some of the seemingly contrasting findings of past research. PMID:21611170

Effect of ternary addition and gamma-irradiation on the characteristics of rapidly solidified Pb-base alloys

NASA Astrophysics Data System (ADS)

Abd El-Khalek, A. M.

The properties of a series of rapidly solidified Pb-Sb-3-Sn-x alloys ( x =0-2.5 wt.%) irradiated with gamma-rays were studied. Variations in the internal friction, Q(-1) , thermal diffusivity D th and dynamic Young's modulus Y were traced before and after irradiation by applying the resonance technique. Variations of specific heat C-p were obtained from DTA thermograms. Structure parameters were obtained from the X-rays diffraction patterns. A marked change in the behaviour of the measured parameters was observed at 1.5 wt.% Sn addition. Besides, irradiation induced defects increased the level of the measured hardening parameters.

A systemic approach to occupational and environmental health.

PubMed

Spitzer, Skip

2005-01-01

As the corporate role in occupational and public health receives increased scrutiny, it is essential to recognize that it is not sufficient to identify specific acts of malfeasance or influence, or even to campaign to address them. A more comprehensive and systemic framework for understanding the role of corporations requires consideration of corporate power and its effects as endemic features of national socioeconomic systems and the rapidly integrating global order. The underlying social structures that produce social and environmental problems, and undermine reform, make systemic change necessary. Identifying this "structure of harm" provides important implications for researchers, policymakers, activists, and others trying to address environmental and social problems, particularly with regard to integrating efforts to address immediate impacts with those for longer-term, systemic change.

The effects of sudden oak death on foliar moisture content and crown fire potential in tanoak

Treesearch

H. Kuljian; J.M. Varner

2010-01-01

The introduction of non-native pathogens can have profound effects on forest ecosystems resulting in loss of species, changes in species composition, and altered fuel structure. The introduction of Phytophthora ramorum, the pathogen recognized as causing Sudden Oak Death (SOD), leads to rapid decline and mortality of tanoak (Lithocarpus densiflorus) in forests of...

Technology Transfer Center to Assume Patenting and Licensing Responsibilities | Poster

Cancer.gov

The NCI Technology Transfer Center (TTC) is undergoing a reorganization that will bring patenting and licensing responsibilities to the Shady Grove and Frederick offices by October 2015. The reorganization is a result of an effort begun in 2014 by NIH to improve the organizational structure of technology transfer at NIH to meet the rapid rate of change within science,

Nurturing the H in HR: Using Action Learning to Build Organisation Development Capability in the UK Civil Service

ERIC Educational Resources Information Center

Hale, Richard; Saville, Martin

2014-01-01

In the UK, the Civil Service Reform Plan is being implemented with urgency. This requires Civil Service departments and agencies to reform their structures and ways of working in order to deliver effective services in a climate of economic austerity and rapid social and technological change. Historically, Human Resource (HR) professionals have…

Determining landscape-scale changes in forest structure and possible management responses to Phytophthora ramorum in the Mt. Tamalpais watershed, Marin County, California

Treesearch

Janet Klein; Andrea Williams; John Menke

2013-01-01

The Marin Municipal Water District's (MMWD) 7487 ha Mt. Tamalpais watershed in Marin County, California has the dubious distinction of being one of the earliest and most extensive areas impacted by Phytophthora ramorum in California. Rapid die off of tanoaks (Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon...

Naval Postgraduate School Fact Book 2004

DTIC Science & Technology

2004-01-01

education to other nations. NPS develops new educational programs, explores different delivery methods and modifies its existing programs to meet the...leadership and the right organizational structure are needed to prepare warriors for the challenges of the future battlespace. To develop the ideas...the rapidly changing needs of the national security. Opportunities for faculty development are available in areas important to the Naval services

Mind the Gap: Physical Education and Health and the Frame Factor Theory as a Tool for Analysing Educational Settings

ERIC Educational Resources Information Center

Lundvall, Suzanne; Meckbach, Jane

2008-01-01

Background: On a normative level as a subject physical education and health seems to adjust rapidly to changes in society, whereas at the practical level it seems receptive to limiting factors such as time, facilities and dominating inherited practices. How can the structuring components and processes relating to the shaping, transformation and…

Politics and Education Policy into Practice: Conversations with Former Secretaries of State

ERIC Educational Resources Information Center

Abbott, Ian

2015-01-01

Set against a period of rapid change, education has grown in political importance and policy development has moved from the local authority to central government with a key role being played by the Secretary of State. Based on a series of semi-structured interviews, with 10 politicians who have served as Secretary of State for Education, this…

Is your organization project management savvy?

PubMed

Wolff, Pam

2003-01-01

As corporations struggle to gain better control and use of organizational resources in a rapidly changing business environment, they're finding that project management is an efficacious discipline for supporting strategic initiatives and achieving business goals. Successful project management requires an understanding of the business drivers, the organizational structure, the benefits of centralizing project management, and the factors that could impact performance.

China's growing CO2 emissions--a race between increasing consumption and efficiency gains.

PubMed

Peters, Glen P; Weber, Christopher L; Guan, Dabo; Hubacek, Klaus

2007-09-01

China's rapidly growing economy and energy consumption are creating serious environmental problems on both local and global scales. Understanding the key drivers behind China's growing energy consumption and the associated CO2 emissions is critical for the development of global climate policies and provides insight into how other emerging economies may develop a low emissions future. Using recently released Chinese economic input-output data and structural decomposition analysis we analyze how changes in China's technology, economic structure, urbanization, and lifestyles affect CO2 emissions. We find that infrastructure construction and urban household consumption, both in turn driven by urbanization and lifestyle changes, have outpaced efficiency improvements in the growth of CO2 emissions. Net trade had a small effect on total emissions due to equal, but significant, growth in emissions from the production of exports and emissions avoided by imports. Technology and efficiency improvements have only partially offset consumption growth, but there remains considerable untapped potential to reduce emissions by improving both production and consumption systems. As China continues to rapidly develop there is an opportunity to further implement and extend policies, such as the Circular Economy, that will help China avoid the high emissions path taken by today's developed countries.

Impacts of Seed Dispersal on Future Vegetation Structure under Changing Climates

NASA Astrophysics Data System (ADS)

Lee, E.; Schlosser, C. A.; Gao, X.; Prinn, R. G.

2011-12-01

As the impacts between land cover change, future climates and ecosystems are expected to be substantial, there are growing needs for improving the capability of simulating the global vegetation structure and landscape as realistically as possible. Current DGVMs assume ubiquitous availability of seeds and do not consider any seed dispersal mechanisms in plant migration process, which may influence the assessment of impacts to the ecosystem that rely on the vegetation structure changes (i.e., change in albedo, runoff, and terrestrial carbon sequestration capacity). This study incorporates time-varying wind-driven seed dispersal (i.e., the SEED configuration) as a dynamic constraint to the migration process of natural vegetation in the Community Land Model (CLM)-DGVM. The SEED configuration is validated using a satellite-derived tree cover dataset. Then the configuration is applied to project future vegetation structures and their implications for carbon fluxes, albedo, and hydrology under two climate mitigation scenarios (No-policy vs. 450ppm CO2 stabilization) for the 21st century. Our results show that regional changes of vegetation structure under changing climates are expected to be significant. For example, Alaska and Siberia are expected to experience substantial shifts of forestry structure, characterized by expansion of needle-leaf boreal forest and shrinkage of C3 grass Arctic. A suggested vulnerability assessment shows that vegetation structures in Alaska, Greenland, Central America, southern South America, East Africa and East Asia are susceptible to changing climates, regardless of the two climate mitigation scenarios. Regions such as Greenland, Tibet, South Asia and Northern Australia, however, may substantially alleviate their risks of rapid change in vegetation structure, given a robust greenhouse gas stabilization target. Proliferation of boreal forests in the high latitudes is expected to amplify the warming trend (i.e., a positive feedback to climate), if no mitigation policy is implemented. In contrast, under the 450ppm scenario, vegetation structure may buffer the warming trend, which is a negative feedback to climate. Moreover, runoff changes due to vegetation shifts may offset or complement runoff changes under anthropogenic climate warming.

Temperature-dependent dynamics of bovine casein micelles in the range 10-40 °C.

PubMed

Liu, Dylan Z; Weeks, Michael G; Dunstan, David E; Martin, Gregory J O

2013-12-15

Milk is a complex colloidal system that responds to changes in temperature imposed during processing. Whilst much has been learned about the effects of temperature on milk, little is known about the dynamic response of casein micelles to changes in temperature. In this study, a comprehensive physico-chemical study of casein micelles in skim milk was performed between 10 and 40 °C. When fully equilibrated, the amount of soluble casein, soluble calcium and the pH of skim milk all decreased as a function of increasing temperature, whilst the hydration and volume fraction of the casein micelles decreased. The effect of temperature on casein micelle size, as determined by dynamic light scattering and differential centrifugation, was less straightforward. Real-time measurements of turbidity and pH were used to investigate the dynamics of the system during warming and cooling of milk in the range 10-40 °C. Changes in pH are indicative of changes to the mineral system and the turbidity is a measure of alterations to the casein micelles. The pH and turbidity showed that alterations to both the casein micelles and the mineral system occurred very rapidly on warming. However, whilst mineral re-equilibration occurred very rapidly on cooling, changes to the casein micelle structure continued after 40 min of measurement, returning to equilibrium after 16 h equilibration. Casein micelle structure and the mineral system of milk were both dependent on temperature in the range 10-40 °C. The dynamic response of the mineral system to changes in temperature appeared almost instantaneous whereas equilibration of casein was considerably slower, particularly upon cooling. Copyright © 2013 Elsevier Ltd. All rights reserved.

A comparison of no-slip, stress-free and inviscid models of rapidly rotating fluid in a spherical shell

PubMed Central

Livermore, Philip W.; Bailey, Lewis M.; Hollerbach, Rainer

2016-01-01

We investigate how the choice of either no-slip or stress-free boundary conditions affects numerical models of rapidly rotating flow in Earth’s core by computing solutions of the weakly-viscous magnetostrophic equations within a spherical shell, driven by a prescribed body force. For non-axisymmetric solutions, we show that models with either choice of boundary condition have thin boundary layers of depth E1/2, where E is the Ekman number, and a free-stream flow that converges to the formally inviscid solution. At Earth-like values of viscosity, the boundary layer thickness is approximately 1 m, for either choice of condition. In contrast, the axisymmetric flows depend crucially on the choice of boundary condition, in both their structure and magnitude (either E−1/2 or E−1). These very large zonal flows arise from requiring viscosity to balance residual axisymmetric torques. We demonstrate that switching the mechanical boundary conditions can cause a distinct change of structure of the flow, including a sign-change close to the equator, even at asymptotically low viscosity. Thus implementation of stress-free boundary conditions, compared with no-slip conditions, may yield qualitatively different dynamics in weakly-viscous magnetostrophic models of Earth’s core. We further show that convergence of the free-stream flow to its asymptotic structure requires E ≤ 10−5. PMID:26980289

Conformational Dynamics of Thermus aquaticus DNA Polymerase I during Catalysis

PubMed Central

Suo, Zucai

2014-01-01

Despite the fact that DNA polymerases have been investigated for many years and are commonly used as tools in a number of molecular biology assays, many details of the kinetic mechanism they use to catalyze DNA synthesis remain unclear. Structural and kinetic studies have characterized a rapid, pre-catalytic open-to-close conformational change of the Finger domain during nucleotide binding for many DNA polymerases including Thermus aquaticus DNA polymerase I (Taq Pol), a thermostable enzyme commonly used for DNA amplification in PCR. However, little has been done to characterize the motions of other structural domains of Taq Pol or any other DNA polymerase during catalysis. Here, we used stopped-flow Förster resonance energy transfer (FRET) to investigate the conformational dynamics of all five structural domains of the full-length Taq Pol relative to the DNA substrate during nucleotide binding and incorporation. Our study provides evidence for a rapid conformational change step induced by dNTP binding and a subsequent global conformational transition involving all domains of Taq Pol during catalysis. Additionally, our study shows that the rate of the global transition was greatly increased with the truncated form of Taq Pol lacking the N-terminal domain. Finally, we utilized a mutant of Taq Pol containing a de novo disulfide bond to demonstrate that limiting protein conformational flexibility greatly reduced the polymerization activity of Taq Pol. PMID:24931550

Division site selection in Escherichia coli involves dynamic redistribution of Min proteins within coiled structures that extend between the two cell poles

NASA Astrophysics Data System (ADS)

Shih, Yu-Ling; Le, Trung; Rothfield, Lawrence

2003-06-01

The MinCDE proteins of Escherichia coli are required for proper placement of the division septum at midcell. The site selection process requires the rapid oscillatory redistribution of the proteins from pole to pole. We report that the three Min proteins are organized into extended membrane-associated coiled structures that wind around the cell between the two poles. The pole-to-pole oscillation of the proteins reflects oscillatory changes in their distribution within the coiled structure. We also report that the E. coli MreB protein, which is required for maintaining the rod shape of the cell, also forms extended coiled structures, which are similar to the MreB structures that have previously been reported in Bacillus subtilis. The MreB and MinCDE coiled arrays do not appear identical. The results suggest that at least two functionally distinct cytoskeletal-like elements are present in E. coli and that structures of this type can undergo dynamic changes that play important roles in division site placement and possibly other aspects of the life of the cell.

Time- and Space-Resolved SAXS Experiments Inform on Phase Transition Kinetics in Hydrated, Liquid-Crystalline Films of Polyion-Surfactant Ion "Complex Salts".

PubMed

Li, Joaquim; Gustavsson, Charlotte; Piculell, Lennart

2016-05-24

Detailed time- and space-resolved SAXS experiments show the variation with hydration of liquid crystalline structures in ethanol-cast 5-80 μm thick films of polyion-surfactant ion "complex salts" (CS). The CS were dodecyl- (C12) or hexadecyl- (C16) trimethylammonium surfactants with polyacrylate (DP 25 or 6000) counter-polyions. The experiments were carried out on vertical films in humid air above a movable water bath, so that gradients of hydration were generated, which could rapidly be altered. Scans over different positions along a film, kept fixed relative to the bath, showed that the surfactant aggregates of the various liquid-crystalline CS structures grow in cross-sectional area with decreasing hydration. This behavior is attributed to the low water content. Studies of films undergoing rapid dehydration, made possible by the original experimental setup, gave strong evidence that some of the investigated systems remain kinetically trapped for minutes in a nonequilibrium Pm3n micellar cubic phase before switching to the equilibrium P6mm 2D hexagonal phase. Both the length of the polyion and the length of the surfactant hydrocarbon "tail" affect the kinetics of the phase transition. The slowness of the cubic-to-hexagonal structural transition is attributed to the fact that it requires major rearrangements of the polyions and surfactant ions relative to each other. By contrast, other structure changes, such as between the hexagonal and rectangular phases, were observed to occur much more rapidly.

An overview of the Douglas Aircraft Company Aeroelastic Design Optimization Program (ADOP)

NASA Technical Reports Server (NTRS)

Dodd, Alan J.

1989-01-01

From a program manager's viewpoint, the history, scope and architecture of a major structural design program at Douglas Aircraft Company called Aeroelastic Design Optimization Program (ADOP) are described. ADOP was originally intended for the rapid, accurate, cost-effective evaluation of relatively small structural models at the advanced design level, resulting in improved proposal competitiveness and avoiding many costly changes later in the design cycle. Before release of the initial version in November 1987, however, the program was expanded to handle very large production-type analyses.

Computer constructed imagery of distant plasma interaction boundaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grenstadt, E.W.; Schurr, H.D.; Tsugawa, R.K.

1982-01-01

Computer constructed sketches of plasma boundaries arising from the interaction between the solar wind and the magnetosphere can serve as both didactic and research tools. In particular, the structure of the earth's bow shock can be represented as a nonuniform surfce according to the instantaneous orientation of the IMF, and temporal changes in structural distribution can be modeled as a sequence of sketches based on observed sequences of spacecraft-based measurements. Viewed rapidly, such a sequence of sketches can be the basis for representation of plasma processes by computer animation.

Four-dimensional Printing of Liquid Crystal Elastomers.

PubMed

Ambulo, Cedric P; Burroughs, Julia J; Boothby, Jennifer M; Kim, Hyun; Shankar, M Ravi; Ware, Taylor H

2017-10-25

Three-dimensional structures capable of reversible changes in shape, i.e., four-dimensional-printed structures, may enable new generations of soft robotics, implantable medical devices, and consumer products. Here, thermally responsive liquid crystal elastomers (LCEs) are direct-write printed into 3D structures with a controlled molecular order. Molecular order is locally programmed by controlling the print path used to build the 3D object, and this order controls the stimulus response. Each aligned LCE filament undergoes 40% reversible contraction along the print direction on heating. By printing objects with controlled geometry and stimulus response, magnified shape transformations, for example, volumetric contractions or rapid, repetitive snap-through transitions, are realized.

Strategic management: a new dimension of the nurse executive's role.

PubMed

Johnson, L J

1990-09-01

The growth of corporate orientation for health care structures, with a focus on bottom-line management, has radically altered the role of nurse executives. With the organization's emphasis on performance, productivity, and results, successful nurse executives are now integrating the management of the delivery of nursing care with the management of complex corporate structures and relationships. The editor of Executive Development discusses the rapidly changing expectations and demands of the contemporary nurse executive's work. The nurse executive's role can be viewed from many perspectives: its scope, its value, its structure, its content. Content--"What does the nurse executive do that makes a real difference?"--is the focus here.

Characterization of Wet-Heat Inactivation of Single Spores of Bacillus Species by Dual-Trap Raman Spectroscopy and Elastic Light Scattering▿

PubMed Central

Zhang, Pengfei; Kong, Lingbo; Setlow, Peter; Li, Yong-qing

2010-01-01

Dual-trap laser tweezers Raman spectroscopy (LTRS) and elastic light scattering (ELS) were used to investigate dynamic processes during high-temperature treatment of individual spores of Bacillus cereus, Bacillus megaterium, and Bacillus subtilis in water. Major conclusions from these studies included the following. (i) After spores of all three species were added to water at 80 to 90°C, the level of the 1:1 complex of Ca2+ and dipicolinic acid (CaDPA; ∼25% of the dry weight of the spore core) in individual spores remained relatively constant during a highly variable lag time (Tlag), and then CaDPA was released within 1 to 2 min. (ii) The Tlag values prior to rapid CaDPA release and thus the times for wet-heat killing of individual spores of all three species were very heterogeneous. (iii) The heterogeneity in kinetics of wet-heat killing of individual spores was not due to differences in the microscopic physical environments during heat treatment. (iv) During the wet-heat treatment of spores of all three species, spore protein denaturation largely but not completely accompanied rapid CaDPA release, as some changes in protein structure preceded rapid CaDPA release. (v) Changes in the ELS from individual spores of all three species were strongly correlated with the release of CaDPA. The ELS intensities of B. cereus and B. megaterium spores decreased gradually and reached minima at T1 when ∼80% of spore CaDPA was released, then increased rapidly until T2 when full CaDPA release was complete, and then remained nearly constant. The ELS intensity of B. subtilis spores showed similar features, although the intensity changed minimally, if at all, prior to T1. (vi) Carotenoids in B. megaterium spores' inner membranes exhibited two changes during heat treatment. First, the carotenoid's two Raman bands at 1,155 and 1,516 cm−1 decreased rapidly to a low value and to zero, respectively, well before Tlag, and then the residual 1,155-cm−1 band disappeared, in parallel with the rapid CaDPA release beginning at Tlag. PMID:20097820

Effect of Chemical Treatments on Flax Fibre Reinforced Polypropylene Composites on Tensile and Dome Forming Behaviour

PubMed Central

Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

2015-01-01

Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

Rapid Succession within the Veillonella Population of a Developing Human Oral Biofilm In Situ

PubMed Central

Palmer, Robert J.; Diaz, Patricia I.; Kolenbrander, Paul E.

2006-01-01

Streptococci are the primary component of the multispecies oral biofilm known as supragingival dental plaque; they grow by fermentation of sugars to organic acids, e.g., lactic acid. Veillonellae, a ubiquitous component of early plaque, are unable to use sugars; they ferment organic acids, such as lactate, to a mixture of shorter-chain-length acids, CO2, and hydrogen. Certain veillonellae bind to (coaggregate with) streptococci in vitro. We show that, between 4 and 8 hours into plaque development, the dominant strains of Veillonella change in their phenotypic characteristics (coaggregation and antibody reactivity) as well as in their genotypic characteristics (16S RNA gene sequences as well as strain level fingerprint patterns). This succession is coordinated with the development of mixed-species bacterial colonies. Changes in community structure can occur very rapidly in natural biofilm development, and we suggest that this process may influence evolution within this ecosystem. PMID:16707703

What can we learn about the dynamics of DO-events from studying the high resolution ice core records?

NASA Astrophysics Data System (ADS)

Ditlevsen, Peter

2017-04-01

The causes for and possible predictions of rapid climate changes are poorly understood. The most pronounced changes observed, beside the glacial terminations, are the Dansgaard-Oeschger events. Present day general circulation climate models simulating glacial conditions are not capable of reproducing these rapid shifts. It is thus not known if they are due to bifurcations in the structural stability of the climate or if they are induced by stochastic fluctuations. By analyzing a high resolution ice core record we exclude the bifurcation scenario, which strongly suggests that they are noise induced and thus have very limited predictability. Ref: Peter Ditlevsen, "Tipping points in the climate system", in Nonlinear and Stochastic Climate Dynamics, Cambridge University Press (C. Franzke and T. O'Kane, eds.) (2016) P. D. Ditlevsen and S. Johnsen, "Tipping points: Early warning and wishful thinking", Geophys. Res. Lett., 37, L19703, 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Binh T; Lehmann, Johannes C; Kinyangi, James

Black carbon (BC) is a quantitatively important C pool in the global carbon cycle due to its relative recalcitrance against decay compared with other C pools. However, how rapidly BC is oxidized and in what way the molecular structure changes during decomposition over decadal time scales, is largely unknown. In the present study, the long-term dynamics in quality and quantity of BC were investigated in cultivated soil using X-ray Photoelectron Spectroscopy (XPS), Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) techniques. BC particles, obtained from soil samples at 8 conversion ages stretching over 100 years and from a forest soilmore » sample from Kenya, were manually picked under a light microscope for characterization and quantification. BC contents rapidly decreased from 12.7 to 3.8 mg C g⁻¹ soil during the first 30 years since conversion, after which they slowly decreased to a steady state at 3.51 mg C g ⁻¹soil. BC-derived C losses over 100 years were estimated at 6000 kg C ha⁻¹ to a depth of 0.1 m. The initial rapid changes in BC stocks resulted in a mean residence time of only around 8.3 years, which was likely a function of both decomposition as well as transport processes. The molecular properties of BC changed more rapidly on surfaces than in the interior of BC particles and more rapidly during the first 30 years than during the following 70 years. The Oc/C ratios (Oc is O bound to C) and carbonyl groups (C=O) increased over time by 133 and 192 %, respectively, indicating oxidation was an important degradation process controlling BC quality. Al, Si, polysaccharides, and to a lesser extent Fe were rapidly adsorbed on BC particle surfaces within the first few years after BC deposition to soil. The protection by physical and chemical stabilization was apparently sufficient to not only minimize decomposition below detection between 30 and 100 years after deposition, but also physical export by erosion and vertical transport below 0.1 m.« less

In-situ High-energy X-ray Diffraction Study of the Local Structure of Supercooled Liquid Si

NASA Technical Reports Server (NTRS)

Lee, G. W.; Kim, T. H.; Sieve, B.; Gangopadhyay, A. K.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, D. S.; Kelton, K. F.; Goldman, A. I.

2005-01-01

While changes in the coordination number for liquid silicon upon supercooling, signaling an underlying liquid-liquid phase transition, have been predicted, x-ray and neutron measurements have produced conflicting reports. In particular some studies have found an increase in the first shell coordination as temperature decreases in the supercooled regime, while others have reported increases in the coordination number with decreasing temperature. Employing the technique of electrostatic levitation coupled with high energy x-ray diffraction (125 keV), and rapid data acquisition (100ms collection times) using an area detector, we have obtained high quality structural data more deeply into the supercooled regime than has been possible before. No change in coordination number is observed in this temperature region, calling into question previous experimental claims of structural evidence for the existence of a liquid-liquid phase transition.

Biomimetic virus-based colourimetric sensors.

PubMed

Oh, Jin-Woo; Chung, Woo-Jae; Heo, Kwang; Jin, Hyo-Eon; Lee, Byung Yang; Wang, Eddie; Zueger, Chris; Wong, Winnie; Meyer, Joel; Kim, Chuntae; Lee, So-Young; Kim, Won-Geun; Zemla, Marcin; Auer, Manfred; Hexemer, Alexander; Lee, Seung-Wuk

2014-01-01

Many materials in nature change colours in response to stimuli, making them attractive for use as sensor platform. However, both natural materials and their synthetic analogues lack selectivity towards specific chemicals, and introducing such selectivity remains a challenge. Here we report the self-assembly of genetically engineered viruses (M13 phage) into target-specific, colourimetric biosensors. The sensors are composed of phage-bundle nanostructures and exhibit viewing-angle independent colour, similar to collagen structures in turkey skin. On exposure to various volatile organic chemicals, the structures rapidly swell and undergo distinct colour changes. Furthermore, sensors composed of phage displaying trinitrotoluene (TNT)-binding peptide motifs identified from a phage display selectively distinguish TNT down to 300 p.p.b. over similarly structured chemicals. Our tunable, colourimetric sensors can be useful for the detection of a variety of harmful toxicants and pathogens to protect human health and national security.

Biomimetic virus-based colourimetric sensors

NASA Astrophysics Data System (ADS)

Oh, Jin-Woo; Chung, Woo-Jae; Heo, Kwang; Jin, Hyo-Eon; Lee, Byung Yang; Wang, Eddie; Zueger, Chris; Wong, Winnie; Meyer, Joel; Kim, Chuntae; Lee, So-Young; Kim, Won-Geun; Zemla, Marcin; Auer, Manfred; Hexemer, Alexander; Lee, Seung-Wuk

2014-01-01

Many materials in nature change colours in response to stimuli, making them attractive for use as sensor platform. However, both natural materials and their synthetic analogues lack selectivity towards specific chemicals, and introducing such selectivity remains a challenge. Here we report the self-assembly of genetically engineered viruses (M13 phage) into target-specific, colourimetric biosensors. The sensors are composed of phage-bundle nanostructures and exhibit viewing-angle independent colour, similar to collagen structures in turkey skin. On exposure to various volatile organic chemicals, the structures rapidly swell and undergo distinct colour changes. Furthermore, sensors composed of phage displaying trinitrotoluene (TNT)-binding peptide motifs identified from a phage display selectively distinguish TNT down to 300 p.p.b. over similarly structured chemicals. Our tunable, colourimetric sensors can be useful for the detection of a variety of harmful toxicants and pathogens to protect human health and national security.

Structural-functional integrated concrete with macro-encapsulated inorganic PCM

NASA Astrophysics Data System (ADS)

Mohseni, Ehsan; Tang, Waiching; Wang, Zhiyu

2017-09-01

Over the last few years the application of thermal energy storage system incorporating phase change materials (PCMs) to foster productivity and efficiency of buildings energy has grown rapidly. In this study, a structural-functional integrated concrete was developed using macro-encapsulated PCM-lightweight aggregate (LWA) as partial replacement (25 and 50% by volume) of coarse aggregate in control concrete. The PCM-LWA was prepared by incorporation of an inorganic PCM into porous LWAs through vacuum impregnation. The mechanical and thermal performance of PCM-LWA concrete were studied. The test results revealed that though the compressive strength of concrete with PCM-LWA was lower than the control concrete, but ranged from 22.02 MPa to 42.88 MPa which above the minimum strength requirement for structural application. The thermal performance test indicated that macro-encapsulated PCM-LWA has underwent the phase change transition reducing the indoor temperature.

Future of African terrestrial biodiversity and ecosystems under anthropogenic climate change

NASA Astrophysics Data System (ADS)

Midgley, Guy F.; Bond, William J.

2015-09-01

Projections of ecosystem and biodiversity change for Africa under climate change diverge widely. More than other continents, Africa has disturbance-driven ecosystems that diversified under low Neogene CO2 levels, in which flammable fire-dependent C4 grasses suppress trees, and mega-herbivore action alters vegetation significantly. An important consequence is metastability of vegetation state, with rapid vegetation switches occurring, some driven by anthropogenic CO2-stimulated release of trees from disturbance control. These have conflicting implications for biodiversity and carbon sequestration relevant for policymakers and land managers. Biodiversity and ecosystem change projections need to account for both disturbance control and direct climate control of vegetation structure and function.

Livestock production systems in developing countries: status, drivers, trends.

PubMed

Steinfeld, H; Wassenaar, T; Jutzi, S

2006-08-01

This paper describes and assesses the current status of livestock production systems, the drivers of global livestock production, and the major trends in such production. The analysis covers the six major livestock species: cattle and buffaloes, goats and sheep, pigs and chickens. Global drivers of the livestock sector include economic growth and income, demographic and land use changes, dietary adjustments and technological change. The rate of change and direction of livestock development vary greatly among world regions, with Asia showing the most rapid growth and structural change. The paper also examines system dynamics, by analysing the ways livestock production has adjusted to external forces. A brief discussion of how these trends link to food safety concludes the paper.

Stress Memory and the Inevitable Effects of Drought: A Physiological Perspective

PubMed Central

Fleta-Soriano, Eva; Munné-Bosch, Sergi

2016-01-01

Plants grow and develop by adjusting their physiology to changes in their environment. Changes in the abiotic environment occur over years, seasons, and days, but also over minutes and even seconds. In this ever-changing environment, plants may adjust their structure and function rapidly to optimize growth and reproduction. Plant responses to reiterated drought (i.e., repeated cycles of drought) differ from those to single incidences of drought; in fact, in nature, plants are usually exposed to repeated cycles of drought that differ in duration and intensity. Nowadays, there is increased interest in better understanding mechanisms of plant response to reiterated drought due, at least in part, to the discovery of epigenomic changes that trigger drought stress memory in plants. Beyond epigenomic changes, there are, however, other aspects that should be considered in the study of plant responses to reiterated drought: from changes in other “omics” approaches (transcriptomics, proteomics, and metabolomics), to changes in plant structure; all of which may help us to better understand plant stress memory and its underlying mechanisms. Here, we present an example in which reiterated drought affects the pigment composition of leaves in the ornamental plant Silene dioica and discuss the importance of structural changes (in this case in the photosynthetic apparatus) for the plant response to reiterated drought; they represent a stress imprint that can affect plant response to subsequent stress episodes. Emphasis is placed on the importance of considering structural changes, in addition to physiological adjustments at the “omics” level, to understand stress memory in plants better. PMID:26913046

Enabling Rapid Integration of Combined Arms Teams into a Brigade Combat Team Organizational Structure

DTIC Science & Technology

2017-06-01

organizational structure , fixed vs. mobile forward operating base (FOB) synchronization, prior preparation, and unit capabilities. 5. Ideas to Improve...Technical Report 1356 Enabling Rapid Integration of Combined Arms Teams into a Brigade Combat Team Organizational Structure ...2012 - May 2014 4. TITLE AND SUBTITLE Enabling Rapid Integration of Combined Arms Teams into a Brigade Combat Team Organizational Structure

Effects of climate change on ecological disturbance in the northern Rockies

USGS Publications Warehouse

Loehman, Rachel A.; Bentz, Barbara J.; DeNitto, Gregg A.; Keane, Robert E.; Manning, Mary E.; Duncan, Jacob P.; Egan, Joel M.; Jackson, Marcus B.; Kegley, Sandra; Lockman, I. Blakey; Pearson, Dean E.; Powell, James A.; Shelly, Steve; Steed, Brytten E.; Zambino, Paul J.; Halofsky, Jessica E.; Peterson, David L.

2018-01-01

Disturbances alter ecosystem, community, or population structure and change elements of the biological and/or physical environment. Climate changes can alter the timing, magnitude, frequency, and duration of disturbance events, as well as the interactions of disturbances on a landscape, and climate change may already be affecting disturbance events and regimes. Interactions among disturbance regimes, such as the cooccurrence in space and time of bark beetle outbreaks and wildfires, can result in highly visible, rapidly occurring, and persistent changes in landscape composition and structure. Understanding how altered disturbance patterns and multiple disturbance interactions might result in novel and emergent landscape behaviors is critical for addressing climate change impacts and for designing land management strategies that are appropriate for future climates This chapter describes the ecology of important disturbance regimes in the Northern Rockies region, and potential shifts in these regimes as a consequence of observed and projected climate change. We summarize five disturbance types present in the Northern Rockies that are sensitive to a changing climate--wildfires, bark beetles, white pine blister rust (Cronartium ribicola), other forest diseases, and nonnative plant invasions—and provide information that can help managers anticipate how, when, where, and why climate changes may alter the characteristics of disturbance regimes.

Structural, Functional, and Genetic Analysis of Sorangicin Inhibition of Bacterial RNA Polymerase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell,E.; Pavlova, O.; Zenkin, N.

2005-01-01

A combined structural, functional, and genetic approach was used to investigate inhibition of bacterial RNA polymerase (RNAP) by sorangicin (Sor), a macrolide polyether antibiotic. Sor lacks chemical and structural similarity to the ansamycin rifampicin (Rif), an RNAP inhibitor widely used to treat tuberculosis. Nevertheless, structural analysis revealed Sor binds in the same RNAP {beta} subunit pocket as Rif, with almost complete overlap of RNAP binding determinants, and functional analysis revealed that both antibiotics inhibit transcription by directly blocking the path of the elongating transcript at a length of 2-3 nucleotides. Genetic analysis indicates that Rif binding is extremely sensitive tomore » mutations expected to change the shape of the antibiotic binding pocket, while Sor is not. We suggest that conformational flexibility of Sor, in contrast to the rigid conformation of Rif, allows Sor to adapt to changes in the binding pocket. This has important implications for drug design against rapidly mutating targets.« less

Experimental evidence of low-density liquid water upon rapid decompression

PubMed Central

Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Shen, Guoyin

2018-01-01

Water is an extraordinary liquid, having a number of anomalous properties which become strongly enhanced in the supercooled region. Due to rapid crystallization of supercooled water, there exists a region that has been experimentally inaccessible for studying deeply supercooled bulk water. Using a rapid decompression technique integrated with in situ X-ray diffraction, we show that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140–165 K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. Together with the change in crystallization rate with temperature, the experimental evidence indicates that the LDN is a low-density liquid (LDL). The measured X-ray diffraction data show that the LDL is tetrahedrally coordinated with the tetrahedral network fully developed and clearly linked to low-density amorphous ices. On the other hand, there is a distinct difference in structure between the LDL and supercooled water or liquid water in terms of the tetrahedral order parameter. PMID:29440411

Structural and molecular remodeling of dendritic spine substructures during long-term potentiation

PubMed Central

Bosch, Miquel; Castro, Jorge; Saneyoshi, Takeo; Matsuno, Hitomi; Sur, Mriganka; Hayashi, Yasunori

2014-01-01

SUMMARY Synapses store information by long-lasting modifications of their structure and molecular composition, but the precise chronology of these changes has not been studied at single synapse resolution in real time. Here we describe the spatiotemporal reorganization of postsynaptic substructures during long-term potentiation (LTP) at individual dendritic spines. Proteins translocated to the spine in four distinct patterns through three sequential phases. In the initial phase, the actin cytoskeleton was rapidly remodeled while active cofilin was massively transported to the spine. In the stabilization phase, cofilin formed a stable complex with F-actin, was persistently retained at the spine, and consolidated spine expansion. In contrast, the postsynaptic density (PSD) was independently remodeled, as PSD scaffolding proteins did not change their amount and localization until a late protein synthesis-dependent third phase. Our findings show how and when spine substructures are remodeled during LTP and explain why synaptic plasticity rules change over time. PMID:24742465

Chemical composition, crystal size and lattice structural changes after incorporation of strontium into biomimetic apatite.

PubMed

Li, Z Y; Lam, W M; Yang, C; Xu, B; Ni, G X; Abbah, S A; Cheung, K M C; Luk, K D K; Lu, W W

2007-03-01

Recently, strontium (Sr) as ranelate compound has become increasingly popular in the treatment of osteoporosis. However, the lattice structure of bone crystal after Sr incorporation is yet to be extensively reported. In this study, we synthesized strontium-substituted hydroxyapatite (Sr-HA) with different Sr content (0.3%, 1.5% and 15% Sr-HA in mole ratio) to simulate bone crystals incorporated with Sr. The changes in chemical composition and lattice structure of apetite after synthetic incorporation of Sr were evaluated to gain insight into bone crystal changes after incorporation of Sr. X-ray diffraction (XRD) patterns revealed that 0.3% and 1.5% Sr-HA exhibited single phase spectrum, which was similar to that of HA. However, 15% Sr-HA induced the incorporation of HPO4(2-) and more CO3(2-), the crystallinity reduced dramatically. Transmission electron microscopy (TEM) images showed that the crystal length and width of 0.3% and 1.5% Sr-HA increased slightly. Meanwhile, the length and width distribution were broadened and the aspect ratio decreased from 10.68+/-4.00 to 7.28+/-2.80. The crystal size and crystallinity of 15% Sr-HA dropped rapidly, which may suggest that the fundamental crystal structure is changed. The findings from this work indicate that current clinical dosage which usually results in Sr incorporation of below 1.5% may not change chemical composition and lattice structure of bone, while it will broaden the bone crystal size distribution and strengthen the bone.

Structural change and higher educated labour in Indonesia.

PubMed

Pasay, N H

1990-12-01

This paper describes an impending shortage of higher-educated labor in Indonesia. Dynamic change is occurring in both Indonesia's population and economy. Its rapidly growing population demands annual national economic growth of 2.2% to avoid declining per capita output. Accordingly, investments have surged in banking and manufacturing industries as Indonesia undergoes structural change from an agricultural to service-based economy. Plagued by a majority of low productivity, elementary-level educated workers, increased productivity is called for to ensure continued development. As the age structural shift progresses, many of these workers will be absorbed in the services sector. Jobs exist requiring workers of all skill levels. This paper is mainly concerned, however, with higher-educated labor's failure to be oriented to the research and development required for sustained economic growth and development, and their entry into clerical positions potentially filled by less educated and less skilled labor. The services sector, particularly public services, is responsible for absorbing much of this labor. As professional, technical, and managerial capabilities and qualifications become increasingly needed in the near future as sector investments take effect, a shortage of higher-educated labor will become apparent. Policy makers are advised to anticipate these shortages and contemplate investments in human capital to facilitate a more smooth adjustment to structural change.

Variation of the chemical reactivity of Thermus thermophilus HB8 ribosomal proteins as a function of pH.

PubMed

Running, William E; Reilly, James P

2010-10-01

Ribosomes occupy a central position in cellular metabolism, converting stored genetic information into active cellular machinery. Ribosomal proteins modulate both the intrinsic function of the ribosome and its interaction with other cellular complexes, such as chaperonins or the signal recognition particle. Chemical modification of proteins combined with mass spectrometric detection of the extent and position of covalent modifications is a rapid, sensitive method for the study of protein structure and flexibility. By altering the pH of the solution, we have induced non-denaturing changes in the structure of bacterial ribosomal proteins and detected these conformational changes by covalent labeling. Changes in ribosomal protein modification across a pH range from 6.6 to 8.3 are unique to each protein, and correlate with their structural environment in the ribosome. Lysine residues whose extent of modification increases as a function of increasing pH are on the surface of proteins, but in close proximity either to glutamate and aspartate residues, or to rRNA backbone phosphates. Increasing pH disrupts tertiary and quaternary interactions mediated by hydrogen bonding or ionic interactions, and regions of protein structure whose conformations are sensitive to these changes are of potential importance in modulating the flexibility of the ribosome or its interaction with other cellular complexes.

El Niño impact on mollusk biomineralization-implications for trace element proxy reconstructions and the paleo-archeological record.

PubMed

Pérez-Huerta, Alberto; Etayo-Cadavid, Miguel F; Andrus, C Fred T; Jeffries, Teresa E; Watkins, Clifton; Street, Shane C; Sandweiss, Daniel H

2013-01-01

Marine macroinvertebrates are ideal sentinel organisms to monitor rapid environmental changes associated with climatic phenomena. These organisms build up protective exoskeletons incrementally by biologically-controlled mineralization, which is deeply rooted in long-term evolutionary processes. Recent studies relating potential rapid environmental fluctuations to climate change, such as ocean acidification, suggest modifications on carbonate biominerals of marine invertebrates. However, the influence of known, and recurrent, climatic events on these biological processes during active mineralization is still insufficiently understood. Analysis of Peruvian cockles from the 1982-83 large magnitude El Niño event shows significant alterations of the chemico-structure of carbonate biominerals. Here, we show that bivalves modify the main biomineralization mechanism during the event to continue shell secretion. As a result, magnesium content increases to stabilize amorphous calcium carbonate (ACC), inducing a rise in Mg/Ca unrelated to the associated increase in sea-surface temperature. Analysis of variations in Sr/Ca also suggests that this proxy should not be used in these bivalves to detect the temperature anomaly, while Ba/Ca peaks are recorded in shells in response to an increase in productivity, or dissolved barium in seawater, after the event. Presented data contribute to a better understanding of the effects of abrupt climate change on shell biomineralization, while also offering an alternative view of bivalve elemental proxy reconstructions. Furthermore, biomineralization changes in mollusk shells can be used as a novel potential proxy to provide a more nuanced historical record of El Niño and similar rapid environmental change events.

Rapid change, climate adversity and the next 'big dry': older farmers' mental health.

PubMed

Polain, John David; Berry, Helen Louise; Hoskin, John Oliver

2011-10-01

To describe the experiences of older farmers in the face of prolonged drought and rapid change. Content analysis of issues and priorities raised in semi-structured community forums. Rural centres in NSW. One hundred and fifty older farmers, their families, Industry and Investment NSW, rural financial and mental health services, the Country Women's Association and other non-government agencies. Five public forums organised under the Rural Adversity Mental Health Program. Prolonged drought caused pressures on farmers that compounded the usual stresses of farming and of ageing. These were experienced in the context of rapid social and industry change, fuel price volatility and the insidious threat of climate change. Three main themes were articulated: loss, government compliance pressures and difficulties accessing and/or inappropriate services. Older farmers felt an overwhelming sense of loss: of profitability and professional success, community status, physical well-being and comfort, the ability to participate in the modern world and, above all, of relationships (partners, children and friends moving away). They interpreted government compliance requirements as evidence of community and government loss of trust in famers. They resisted using the few mental health services that might be available, fearing being labelled as 'crazy' and discouraged by the culturally inappropriate way in which services were offered. Older farmers would benefit from joint services related to health and well-being simultaneously with modern business management offered in trusted, comfortable settings. © 2011 The Authors. Australian Journal of Rural Health © National Rural Health Alliance Inc.

Influence of volcanic activity on the population genetic structure of Hawaiian Tetragnatha spiders: Fragmentation, rapid population growth and the potential for accelerated evolution

USGS Publications Warehouse

Vandergast, A.G.; Gillespie, R.G.; Roderick, G.K.

2004-01-01

Volcanic activity on the island of Hawaii results in a cyclical pattern of habitat destruction and fragmentation by lava, followed by habitat regeneration on newly formed substrates. While this pattern has been hypothesized to promote the diversification of Hawaiian lineages, there have been few attempts to link geological processes to measurable changes in population structure. We investigated the genetic structure of three species of Hawaiian spiders in forests fragmented by a 150-year-old lava flow on Mauna Loa Volcano, island of Hawaii: Tetragnatha quasimodo (forest and lava flow generalist), T. anuenue and T. brevignatha (forest specialists). To estimate fragmentation effects on population subdivision in each species, we examined variation in mitochondrial and nuclear genomes (DNA sequences and allozymes, respectively). Population subdivision was higher for forest specialists than for the generalist in fragments separated by lava. Patterns of mtDNA sequence evolution also revealed that forest specialists have undergone rapid expansion, while the generalist has experienced more gradual population growth. Results confirm that patterns of neutral genetic variation reflect patterns of volcanic activity in some Tetragnatha species. Our study further suggests that population subdivision and expansion can occur across small spatial and temporal scales, which may facilitate the rapid spread of new character states, leading to speciation as hypothesized by H. L. Carson 30 years ago.

Reversible changes in pancreatic islet structure and function produced by elevated blood glucose

PubMed Central

Brereton, Melissa F.; Iberl, Michaela; Shimomura, Kenju; Zhang, Quan; Adriaenssens, Alice E.; Proks, Peter; Spiliotis, Ioannis I.; Dace, William; Mattis, Katia K.; Ramracheya, Reshma; Gribble, Fiona M.; Reimann, Frank; Clark, Anne; Rorsman, Patrik; Ashcroft, Frances M.

2014-01-01

Diabetes is characterized by hyperglycaemia due to impaired insulin secretion and aberrant glucagon secretion resulting from changes in pancreatic islet cell function and/or mass. The extent to which hyperglycaemia per se underlies these alterations remains poorly understood. Here we show that β-cell-specific expression of a human activating KATP channel mutation in adult mice leads to rapid diabetes and marked alterations in islet morphology, ultrastructure and gene expression. Chronic hyperglycaemia is associated with a dramatic reduction in insulin-positive cells and an increase in glucagon-positive cells in islets, without alterations in cell turnover. Furthermore, some β-cells begin expressing glucagon, whilst retaining many β-cell characteristics. Hyperglycaemia, rather than KATP channel activation, underlies these changes, as they are prevented by insulin therapy and fully reversed by sulphonylureas. Our data suggest that many changes in islet structure and function associated with diabetes are attributable to hyperglycaemia alone and are reversed when blood glucose is normalized. PMID:25145789

The organization and practice of East Asian medicine in Japan: continuity and change.

PubMed

Lock, M

1980-11-01

The historical development, structure, and organization of traditional East Asian medicine are summarized as background for a discussion of the popular revival of traditional medicine in Japan. Despite evolution and development of traditional medical practice, continuity in attitudes toward medical theory, the concept of holism, and the demonstration of empathy is noted. The main changes have occurred in theories of disease causation and terminology. Revival of interest in East Asian medical systems is explained by a surge of nationalism following rapid social change in Japan, a new emphasis on ecological and cybernetic models, changes in the epidemiology of disease with chronic diseases assuming a more important role, and desire to avoid toxic drugs. Factionalism, competitition and innovation are encouraged by the structure of traditional medicine in Japan. Incorporation of traditional medicine into the organization of cosmopolitan medicine and application of the standards of science to it would probably result in the loss of its special features which are of value to patients.

Antiquity of the South Atlantic Anomaly and evidence for top-down control on the geodynamo

PubMed Central

Tarduno, John A.; Watkeys, Michael K.; Huffman, Thomas N.; Cottrell, Rory D.; Blackman, Eric G.; Wendt, Anna; Scribner, Cecilia A.; Wagner, Courtney L.

2015-01-01

The dramatic decay of dipole geomagnetic field intensity during the last 160 years coincides with changes in Southern Hemisphere (SH) field morphology and has motivated speculation of an impending reversal. Understanding these changes, however, has been limited by the lack of longer-term SH observations. Here we report the first archaeomagnetic curve from southern Africa (ca. 1000–1600 AD). Directions change relatively rapidly at ca. 1300 AD, whereas intensities drop sharply, at a rate greater than modern field changes in southern Africa, and to lower values. We propose that the recurrence of low field strengths reflects core flux expulsion promoted by the unusual core–mantle boundary (CMB) composition and structure beneath southern Africa defined by the African large low shear velocity province (LLSVP). Because the African LLSVP and CMB structure are ancient, this region may have been a steady site for flux expulsion, and triggering of geomagnetic reversals, for millions of years. PMID:26218786

On aerobic exercise and behavioral and neural plasticity.

PubMed

Swain, Rodney A; Berggren, Kiersten L; Kerr, Abigail L; Patel, Ami; Peplinski, Caitlin; Sikorski, Angela M

2012-11-29

Aerobic exercise promotes rapid and profound alterations in the brain. Depending upon the pattern and duration of exercise, these changes in the brain may extend beyond traditional motor areas to regions and structures normally linked to learning, cognition, and emotion. Exercise-induced alterations may include changes in blood flow, hormone and growth factor release, receptor expression, angiogenesis, apoptosis, neurogenesis, and synaptogenesis. Together, we believe that these changes underlie elevations of mood and prompt the heightened behavioral plasticity commonly observed following adoption of a chronic exercise regimen. In the following paper, we will explore both the psychological and psychobiological literatures relating to exercise effects on brain in both human and non-human animals and will attempt to link plastic changes in these neural structures to modifications in learned behavior and emotional expression. In addition, we will explore the therapeutic potential of exercise given recent reports that aerobic exercise may serve as a neuroprotectant and can also slow cognitive decline during normal and pathological aging.

On Aerobic Exercise and Behavioral and Neural Plasticity

PubMed Central

Swain, Rodney A.; Berggren, Kiersten L.; Kerr, Abigail L.; Patel, Ami; Peplinski, Caitlin; Sikorski, Angela M.

2012-01-01

Aerobic exercise promotes rapid and profound alterations in the brain. Depending upon the pattern and duration of exercise, these changes in the brain may extend beyond traditional motor areas to regions and structures normally linked to learning, cognition, and emotion. Exercise-induced alterations may include changes in blood flow, hormone and growth factor release, receptor expression, angiogenesis, apoptosis, neurogenesis, and synaptogenesis. Together, we believe that these changes underlie elevations of mood and prompt the heightened behavioral plasticity commonly observed following adoption of a chronic exercise regimen. In the following paper, we will explore both the psychological and psychobiological literatures relating to exercise effects on brain in both human and non-human animals and will attempt to link plastic changes in these neural structures to modifications in learned behavior and emotional expression. In addition, we will explore the therapeutic potential of exercise given recent reports that aerobic exercise may serve as a neuroprotectant and can also slow cognitive decline during normal and pathological aging. PMID:24961267

Rapid detection of biofilms and adherent pathogens using scanning confocal laser microscopy and episcopic differential interference contrast microscopy.

PubMed

Keevil, C W

2003-01-01

Knowledge of biofilm structure and function has changed significantly in the last few years due to advances in light microscopy. One pertinent example is the use of scanning confocal laser microscopy (SCLM) to visualise corrosion pits caused by the biofilm mosaic footprint on corroding metal surfaces. Nevertheless, SCLM has some limitations as to its widespread use, including cost, inability to observe motile bacteria and eukaryotic grazers within biofilms, and difficulty to scan a curved surface. By contrast, episcopic differential interference contrast (EDIC) microscopy has provided a rapid, real time analysis of biofilms on opaque, curved, natural or man-made surfaces without the need for cover slips and oil. EDIC, coupled with epi-fluorescence (EDIC/EF), microscopy has been used successfully to visualise the 3-D biofilm structure, physiological niches, protozoal grazing and iron biomineralization, and the location of specific pathogens such as Legionella pneumophila, Campylobacter jejuni and Cryptosporidium parvum. These species were identified using gold nanoparticles or fluorophores coupled to monoclonal antibodies or 16S rRNA probes, respectively. Among its many potential uses, the EDIC technique will provide a rapid procedure to facilitate the calibration of the modern generation of biofilm-sensing electrodes.

Thermal Tomography of Asteroid Surface Structure

NASA Astrophysics Data System (ADS)

Harris, Alan W.; Drube, Line

2016-12-01

Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

Diet rapidly and reproducibly alters the human gut microbiome

PubMed Central

David, Lawrence A.; Maurice, Corinne F.; Carmody, Rachel N.; Gootenberg, David B.; Button, Julie E.; Wolfe, Benjamin E.; Ling, Alisha V.; Devlin, A. Sloan; Varma, Yug; Fischbach, Michael A.; Biddinger, Sudha B.; Dutton, Rachel J.; Turnbaugh, Peter J.

2013-01-01

Long-term diet influences the structure and activity of the trillions of microorganisms residing in the human gut1–5, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here, we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila, and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale, and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals2, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi, and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids, and the outgrowth of microorganisms capable of triggering inflammatory bowel disease6. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles. PMID:24336217

THERMAL TOMOGRAPHY OF ASTEROID SURFACE STRUCTURE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Alan W.; Drube, Line, E-mail: alan.harris@dlr.de

Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) tomore » 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.« less

Changing the Structure and Functioning of an Organization: Report of a Field Experiment. Monograph No. 33.

ERIC Educational Resources Information Center

Seashore, Stanley E.; Bowers, David G.

A three-year study was made at a printing firm which had experienced rapid post-war expansion followed by conditions of tension, uncertainty, and confusion when some product lines were found to be in over supply or unprofitable. There was a growing distance between management and workers. An experimental program for three of the five company…

Culture of fire and environmental education in wildfire-prone areas: current situation in Spain

Treesearch

Clara Quesada-Fernández; Daniel Quesada-Fernández

2013-01-01

The culture of fire in the context of climate change has become a complicated relationship between people and natural areas. The interaction between people and fire is not a new issue. The use of fire by humans in most aspects of life, especially in rural areas, together with rapid and haphazard growth of structures in wildfire-prone areas, has led...

Physiological responses of eastern hemlock (Tsuga Canadensis) to biological control and silvicultural release: implications for hemlock restoration

Treesearch

Chelcy F. Miniat; David Zeitlow; Steven T. Brantley; Albert (Bud) Mayfield; Rusty Rhea; Robert Jetton; Paul.  Arnold

2016-01-01

The rapid loss of eastern hemlock (Tsuga canadensis) from riparian zones in the southern Appalachian Mountains due to Hemlock Woolly Adelgid (Adelgis tsugae, HWA) infestation has resulted in changes to watershed structure and function. Several restoration strategies have been proposed, including silvicultural treatments that increase incident light in forest...

Changes in the Relative Labor Force Status of Black and White Youths: A Review of the Literature.

ERIC Educational Resources Information Center

Mare, Robert D.; Winship, Christopher

Since World War II, unemployment rates for black youths have risen much more rapidly than for white youths. This report reviews possible causes of the worsening relative employment status of black youths, including market and structural trends in the sizes of labor force entry cohorts, competition in the low-wage labor market from women and…

Incorporating Physical, Social, and Institutional Changes in Water Resources Planning and Management

DTIC Science & Technology

2014-06-01

species (fish, mussels, mam- mals, birds , and plants) 5. Aesthetic resources 6. Human health and safety 7. Land use 8. Transportation and traffic...focused Rapid Impact Assessment Method (RIAM) which is based on evaluation of six criteria: endangered species habitat , structural diversity of habitats ...additional issues include detrimental consequences to aquatic ecosystems, habitats , and interdependent riparian and aquatic species . To provide an

Television, disordered eating, and young women in Fiji: negotiating body image and identity during rapid social change.

PubMed

Becker, Anne E

2004-12-01

Although the relationship between media exposure and risk behavior among youth is established at a population level, the specific psychological and social mechanisms mediating the adverse effects of media on youth remain poorly understood. This study reports on an investigation of the impact of the introduction of television to a rural community in Western Fiji on adolescent ethnic Fijian girls in a setting of rapid social and economic change. Narrative data were collected from 30 purposively selected ethnic Fijian secondary school girls via semi-structured, open-ended interviews. Interviews were conducted in 1998, 3 years after television was first broadcast to this region of Fiji. Narrative data were analyzed for content relating to response to television and mechanisms that mediate self and body image in Fijian adolescents. Data in this sample suggest that media imagery is used in both creative and destructive ways by adolescent Fijian girls to navigate opportunities and conflicts posed by the rapidly changing social environment. Study respondents indicated their explicit modeling of the perceived positive attributes of characters presented in television dramas, but also the beginnings of weight and body shape preoccupation, purging behavior to control weight, and body disparagement. Response to television appeared to be shaped by a desire for competitive social positioning during a period of rapid social transition. Understanding vulnerability to images and values imported with media will be critical to preventing disordered eating and, potentially, other youth risk behaviors in this population, as well as other populations at risk.

Structure of rapidity divergences in multi-parton scattering soft factors

NASA Astrophysics Data System (ADS)

Vladimirov, Alexey

2018-04-01

We discuss the structure of rapidity divergences that are presented in the soft factors of transverse momentum dependent (TMD) factorization theorems. To provide the discussion on the most general level we consider soft factors for multi-parton scattering. We show that the rapidity divergences are result of the gluon exchanges with the distant transverse plane, and are structurally equivalent to the ultraviolet divergences. It allows to formulate and to prove the renormalization theorem for rapidity divergences. The proof is made with the help the conformal transformation which maps rapidity divergences to ultraviolet divergences. The theorem is the systematic form of the factorization of rapidity divergences, which is required for the definition of TMD parton distributions. In particular, the definition of multi parton distributions is presented. The equivalence of ultraviolet and rapidity divergences leads to the exact relation between soft and rapidity anomalous dimensions. Using this relation we derive the rapidity anomalous dimension at the three-loop order.

Butterflies, Black swans and Dragon kings: How to use the Dynamical Systems Theory to build a "zoology" of mid-latitude circulation atmospheric extremes?

NASA Astrophysics Data System (ADS)

Faranda, D.; Yiou, P.; Alvarez-Castro, M. C. M.

2015-12-01

A combination of dynamical systems and statistical techniques allows for a robust assessment of the dynamical properties of the mid-latitude atmospheric circulation. Extremes at different spatial and time scales are not only associated to exceptionally intense weather structures (e.g. extra-tropical cyclones) but also to rapid changes of circulation regimes (thunderstorms, supercells) or the extreme persistence of weather structure (heat waves, cold spells). We will show how the dynamical systems theory of recurrence combined to the extreme value theory can take into account the spatial and temporal dependence structure of the mid-latitude circulation structures and provide information on the statistics of extreme events.

Remote Strain Sensing of CFRP Using Microwave Frequency Domain Reflectometry

NASA Technical Reports Server (NTRS)

Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

2016-01-01

NASA's Advanced Composites Project is investigating technologies that increase automated remote inspection of aircraft composite structures. Therefore, microwave Frequency Domain Reflectometry (FDR) is being investigated as a method of enabling rapid remote measurement of strain occurring at the first ply of a composite fiber reinforced polymer (CFRP) structure using Radio Frequency (RF) Electro-Magnetic (EM) radiation. While microwave reflectometry has been used to detect disbonds in CFRP structures, its use in detecting strain has been limited. This work will present data demonstrating the measurement of the reactance changes due to loading conditions that are indicative of strain in a CFRP structure. In addition, the basic EM signature will be presented along with an analysis of temperature and humidity effects.

Parameter optimization on the convergence surface of path simulations

NASA Astrophysics Data System (ADS)

Chandrasekaran, Srinivas Niranj

Computational treatments of protein conformational changes tend to focus on the trajectories themselves, despite the fact that it is the transition state structures that contain information about the barriers that impose multi-state behavior. PATH is an algorithm that computes a transition pathway between two protein crystal structures, along with the transition state structure, by minimizing the Onsager-Machlup action functional. It is rapid but depends on several unknown input parameters whose range of different values can potentially generate different transition-state structures. Transition-state structures arising from different input parameters cannot be uniquely compared with those generated by other methods. I outline modifications that I have made to the PATH algorithm that estimates these input parameters in a manner that circumvents these difficulties, and describe two complementary tests that validate the transition-state structures found by the PATH algorithm. First, I show that although the PATH algorithm and two other approaches to computing transition pathways produce different low-energy structures connecting the initial and final ground-states with the transition state, all three methods agree closely on the configurations of their transition states. Second, I show that the PATH transition states are close to the saddle points of free-energy surfaces connecting initial and final states generated by replica-exchange Discrete Molecular Dynamics simulations. I show that aromatic side-chain rearrangements create similar potential energy barriers in the transition-state structures identified by PATH for a signaling protein, a contractile protein, and an enzyme. Finally, I observed, but cannot account for, the fact that trajectories obtained for all-atom and Calpha-only simulations identify transition state structures in which the Calpha atoms are in essentially the same positions. The consistency between transition-state structures derived by different algorithms for unrelated protein systems argues that although functionally important protein conformational change trajectories are to a degree stochastic, they nonetheless pass through a well-defined transition state whose detailed structural properties can rapidly be identified using PATH. In the end, I outline the strategies that could enhance the efficiency and applicability of PATH.

Tunable broadband near-infrared absorber based on ultrathin phase-change material

NASA Astrophysics Data System (ADS)

Hu, Er-Tao; Gu, Tong; Guo, Shuai; Zang, Kai-Yan; Tu, Hua-Tian; Yu, Ke-Han; Wei, Wei; Zheng, Yu-Xiang; Wang, Song-You; Zhang, Rong-Jun; Lee, Young-Pak; Chen, Liang-Yao

2017-11-01

In this work, a tunable broadband near-infrared light absorber was designed and fabricated with a simple and lithography free approach by introducing an ultrathin phase-change material Ge2Sb2Te5 (GST) layer into the metal-dielectric multilayered film structure with the structure parameters as that: SiO2 (72.7 nm)/Ge2Sb2Te5 (6.0 nm)/SiO2 (70.2 nm)/Cu (>100.0 nm). The film structure exhibits a modulation depth of ∼72.6% and an extinction ratio of ∼8.8 dB at the wavelength of 1410 nm. The high light absorption (95%) of the proposed film structure at the wavelength of 450 nm in both of the amorphous and crystalline phase of GST, indicates that the intensity of the reflectance in the infrared region can be rapidly tuned by the blue laser pulses. The proposed planar layered film structure with layer thickness as the only controllable parameter and large reflectivity tuning range shows the potential for practical applications in near-infrared light modulation and absorption.

Analysis of population genetic structure and gene flow in an annual plant before and after a rapid evolutionary response to drought.

PubMed

Welt, Rachel S; Litt, Amy; Franks, Steven J

2015-03-27

The impact of environmental change on population structure is not well understood. This study aimed to examine the effect of a climate change event on gene flow over space and time in two populations of Brassica rapa that evolved more synchronous flowering times over 5 years of drought in southern California. Using plants grown from seeds collected before and after the drought, we estimated genetic parameters within and between populations and across generations. We expected that with greater temporal opportunity to cross-pollinate, due to reduced phenological isolation, these populations would exhibit an increase in gene flow following the drought. We found low but significant FST, but no change in FST or Nm across the drought, in contrast to predictions. Bayesian analysis of these data indicates minor differentiation between the two populations but no noticeable change in structure before and after the shift in flowering times. However, we found high and significant levels of FIS, indicating that inbreeding likely occurred in these populations despite self-incompatibility in B. rapa. In this system, we did not find an impact of climate change on gene flow or population structuring. The contribution of gene flow to adaptive evolution may vary by system, however, and is thus an important parameter to consider in further studies of natural responses to environmental change. Published by Oxford University Press on behalf of the Annals of Botany Company.

Rapid response to changing environments during biological invasions: DNA methylation perspectives.

PubMed

Huang, Xuena; Li, Shiguo; Ni, Ping; Gao, Yangchun; Jiang, Bei; Zhou, Zunchun; Zhan, Aibin

2017-12-01

Dissecting complex interactions between species and their environments has long been a research hot spot in the fields of ecology and evolutionary biology. The well-recognized Darwinian evolution has well-explained long-term adaptation scenarios; however, "rapid" processes of biological responses to environmental changes remain largely unexplored, particularly molecular mechanisms such as DNA methylation that have recently been proposed to play crucial roles in rapid environmental adaptation. Invasive species, which have capacities to successfully survive rapidly changing environments during biological invasions, provide great opportunities to study molecular mechanisms of rapid environmental adaptation. Here, we used the methylation-sensitive amplified polymorphism (MSAP) technique in an invasive model ascidian, Ciona savignyi, to investigate how species interact with rapidly changing environments at the whole-genome level. We detected quite rapid DNA methylation response: significant changes of DNA methylation frequency and epigenetic differentiation between treatment and control groups occurred only after 1 hr of high-temperature exposure or after 3 hr of low-salinity challenge. In addition, we detected time-dependent hemimethylation changes and increased intragroup epigenetic divergence induced by environmental stresses. Interestingly, we found evidence of DNA methylation resilience, as most stress-induced DNA methylation variation maintained shortly (~48 hr) and quickly returned back to the control levels. Our findings clearly showed that invasive species could rapidly respond to acute environmental changes through DNA methylation modifications, and rapid environmental changes left significant epigenetic signatures at the whole-genome level. All these results provide fundamental background to deeply investigate the contribution of DNA methylation mechanisms to rapid contemporary environmental adaptation. © 2017 John Wiley & Sons Ltd.

Nanosecond Absorption Spectroscopy of Hemoglobin: Elementary Processes in Kinetic Cooperativity

NASA Astrophysics Data System (ADS)

Hofrichter, James; Sommer, Joseph H.; Henry, Eric R.; Eaton, William A.

1983-04-01

A nanosecond absorption spectrometer has been used to measure the optical spectra of hemoglobin between 3 ns and 100 ms after photolysis of the CO complex. The data from a single experiment comprise a surface, defined by the time-ordered set of 50-100 spectra. Singular value decomposition is used to represent the observed spectra in terms of a minimal set of basis spectra and the time course of their amplitudes. Both CO rebinding and conformational changes are found to be multiphasic. Prior to the quaternary structural change, two relaxations are observed that are assigned to geminate recombination followed by a tertiary structural change. These relaxations are interpreted in terms of a kinetic model that points out their potential role in kinetic cooperativity. The rapid escape of CO from the heme pocket compared with the rate of rebinding observed for both R and T quaternary states shows that the quaternary structure controls the overall dissociation rate by changing the rate at which the Fe--CO bond is broken. A comparable description of the control of the overall association rates must await a more complete experimental description of the kinetics of the quaternary T state.

Conformational changes accompany activation of reovirus RNA-dependent RNA transcription

PubMed Central

Mendez, Israel I.; Weiner, Scott G.; She, Yi-Min; Yeager, Mark; Coombs, Kevin M.

2009-01-01

Many critical biologic processes involve dynamic interactions between proteins and nucleic acids. Such dynamic processes are often difficult to delineate by conventional static methods. For example, while a variety of nucleic acid polymerase structures have been determined at atomic resolution, the details of how some multi-protein transcriptase complexes actively produce mRNA, as well as conformational changes associated with activation of such complexes, remain poorly understood. The mammalian reovirus innermost capsid (core) manifests all enzymatic activities necessary to produce mRNA from each of the 10 encased double-stranded RNA genes. We used rapid freezing and electron cryo-microscopy to trap and visualize transcriptionally active reovirus core particles and compared them to inactive core images. Rod-like density centered within actively transcribing core spike channels was attributed to exiting nascent mRNA. Comparative radial density plots of active and inactive core particles identified several structural changes in both internal and external regions of the icosahedral core capsid. Inactive and transcriptionally active cores were partially digested with trypsin and identities of initial tryptic peptides determined by mass spectrometry. Differentially-digested peptides, which also suggest transcription-associated conformational changes, were placed within the known 3-dimensional structures of major core proteins. PMID:18321727

Concerted Interconversion between Ionic Lock Substates of the β2 Adrenergic Receptor Revealed by Microsecond Timescale Molecular Dynamics

PubMed Central

Romo, Tod D.; Grossfield, Alan; Pitman, Michael C.

2010-01-01

Abstract The recently solved crystallographic structures for the A2A adenosine receptor and the β1 and β2 adrenergic receptors have shown important differences between members of the class-A G-protein-coupled receptors and their archetypal model, rhodopsin, such as the apparent breaking of the ionic lock that stabilizes the inactive structure. Here, we characterize a 1.02 μs all-atom simulation of an apo-β2 adrenergic receptor that is missing the third intracellular loop to better understand the inactive structure. Although we find that the structure is remarkably rigid, there is a rapid influx of water into the core of the protein, as well as a slight expansion of the molecule relative to the crystal structure. In contrast to the x-ray crystal structures, the ionic lock rapidly reforms, although we see an activation-precursor-like event wherein the ionic lock opens for ∼200 ns, accompanied by movements in the transmembrane helices associated with activation. When the lock reforms, we see the structure return to its inactive conformation. We also find that the ionic lock exists in three states: closed (or locked), semi-open with a bridging water molecule, and open. The interconversion of these states involves the concerted motion of the entire protein. We characterize these states and the concerted motion underlying their interconversion. These findings may help elucidate the connection between key local events and the associated global structural changes during activation. PMID:20074514

The changing relationship between family size and educational attainment over the course of socioeconomic development: evidence from Indonesia.

PubMed

Maralani, Vida

2008-08-01

Many studies from developed countries show a negative correlation between family size and children's schooling, while results from developing countries show this association ranging from positive to neutral to negative, depending on the context. The body of evidence suggests that this relationship changes as a society develops, but this theory has been difficult to assess because the existing evidence requires comparisons across countries with different social structures and at different levels of development. The world's fourth most populous nation in 2007, Indonesia has developed rapidly in recent decades. This context provides the opportunity to study these relationships within the same rapidly developing setting to see if and how these associations change. Results show that in urban areas, the association between family size and children's schooling was positive for older cohorts but negative for more recent cohorts. Models using instrumental variables to address the potential endogeneity of fertility confirm these results. In contrast, rural areas show no significant association between family size and children's schooling for any cohort. These findings show how the relationship between family size and children's schooling can differ within the same country and change over time as contextual factors evolve with socioeconomic development.

Rapid treatment-induced brain changes in pediatric CRPS.

PubMed

Erpelding, Nathalie; Simons, Laura; Lebel, Alyssa; Serrano, Paul; Pielech, Melissa; Prabhu, Sanjay; Becerra, Lino; Borsook, David

2016-03-01

To date, brain structure and function changes in children with complex regional pain syndrome (CRPS) as a result of disease and treatment remain unknown. Here, we investigated (a) gray matter (GM) differences between patients with CRPS and healthy controls and (b) GM and functional connectivity (FC) changes in patients following intensive interdisciplinary psychophysical pain treatment. Twenty-three patients (13 females, 9 males; average age ± SD = 13.3 ± 2.5 years) and 21 healthy sex- and age-matched controls underwent magnetic resonance imaging. Compared to controls, patients had reduced GM in the primary motor cortex, premotor cortex, supplementary motor area, midcingulate cortex, orbitofrontal cortex, dorsolateral prefrontal cortex (dlPFC), posterior cingulate cortex, precuneus, basal ganglia, thalamus, and hippocampus. Following treatment, patients had increased GM in the dlPFC, thalamus, basal ganglia, amygdala, and hippocampus, and enhanced FC between the dlPFC and the periaqueductal gray, two regions involved in descending pain modulation. Accordingly, our results provide novel evidence for GM abnormalities in sensory, motor, emotional, cognitive, and pain modulatory regions in children with CRPS. Furthermore, this is the first study to demonstrate rapid treatment-induced GM and FC changes in areas implicated in sensation, emotion, cognition, and pain modulation.

Lignin structural alterations in thermochemical pretreatments with limited delignification

DOE PAGES

Pu, Yunqiao; Hu, Fan; Huang, Fang; ...

2015-08-02

Lignocellulosic biomass has a complex and rigid cell wall structure that makes biomass recalcitrant to biological and chemical degradation. Among the three major structural biopolymers (i.e., cellulose, hemicellulose and lignin) in plant cell walls, lignin is considered the most recalcitrant component and generally plays a negative role in the biochemical conversion of biomass to biofuels. The conversion of biomass to biofuels through a biochemical platform usually requires a pretreatment stage to reduce the recalcitrance. Pretreatment renders compositional and structural changes of biomass with these changes ultimately govern the efficiency of the subsequent enzymatic hydrolysis. Dilute acid, hot water, steam explosion,more » and ammonia fiber expansion pretreatments are among the leading thermochemical pretreatments with a limited delignification that can reduce biomass recalcitrance. Practical applications of these pretreatment are rapidly developing as illustrated by recent commercial scale cellulosic ethanol plants. While these thermochemical pretreatments generally lead to only a limited delignification and no significant change of lignin content in the pretreated biomass, the lignin transformations that occur during these pretreatments and the roles they play in recalcitrance reduction is an important research aspect. This review highlights recent advances in our understanding of lignin alterations during these limited delignification thermochemical pretreatments, with emphasis on lignin chemical structures, molecular weights, and redistributions in the pretreated biomass.« less

Investigation of the effects of miniscrew-assisted rapid palatal expansion on airflow in the upper airway of an adult patient with obstructive sleep apnea syndrome using computational fluid-structure interaction analysis

PubMed Central

Hur, Jae-Sik; Kim, Hyoung-Ho; Choi, Jin-Young; Suh, Sang-Ho

2017-01-01

Objective The objective of this study was to investigate the effects of miniscrew-assisted rapid palatal expansion (MARPE) on changes in airflow in the upper airway (UA) of an adult patient with obstructive sleep apnea syndrome (OSAS) using computational fluid-structure interaction analysis. Methods Three-dimensional UA models fabricated from cone beam computed tomography images obtained before (T0) and after (T1) MARPE in an adult patient with OSAS were used for computational fluid dynamics with fluid-structure interaction analysis. Seven and nine cross-sectional planes (interplane distance of 10 mm) in the nasal cavity (NC) and pharynx, respectively, were set along UA. Changes in the cross-sectional area and changes in airflow velocity and pressure, node displacement, and total resistance at maximum inspiration (MI), rest, and maximum expiration (ME) were investigated at each plane after MARPE. Results The cross-sectional areas at most planes in NC and the upper half of the pharynx were significantly increased at T1. Moreover, airflow velocity decreased in the anterior NC at MI and ME and in the nasopharynx and oropharynx at MI. The decrease in velocity was greater in NC than in the pharynx. The airflow pressure in the anterior NC and entire pharynx exhibited a decrease at T1. The amount of node displacement in NC and the pharynx was insignificant at both T0 and T1. Absolute values for the total resistance at MI, rest, and ME were lower at T1 than at T0. Conclusions MARPE improves airflow and decreases resistance in UA; therefore, it may be an effective treatment modality for adult patients with moderate OSAS. PMID:29090123

Metagenomics-Enabled Understanding of Soil Microbial Feedbacks to Climate Warming

NASA Astrophysics Data System (ADS)

Zhou, J.; Wu, L.; Zhili, H.; Kostas, K.; Luo, Y.; Schuur, E. A. G.; Cole, J. R.; Tiedje, J. M.

2014-12-01

Understanding the response of biological communities to climate warming is a central issue in ecology and global change biology, but it is poorly understood microbial communities. To advance system-level predictive understanding of the feedbacks of belowground microbial communities to multiple climate change factors and their impacts on soil carbon (C) and nitrogen (N) cycling processes, we have used integrated metagenomic technologies (e.g., target gene and shotgun metagenome sequencing, GeoChip, and isotope) to analyze soil microbial communities from experimental warming sites in Alaska (AK) and Oklahoma (OK), and long-term laboratory incubation. Rapid feedbacks of microbial communities to warming were observed in the AK site. Consistent with the changes in soil temperature, moisture and ecosystem respiration, microbial functional community structure was shifted after only 1.5-year warming, indicating rapid responses and high sensitivity of this permafrost ecosystem to climate warming. Also, warming stimulated not only functional genes involved in aerobic respiration of both labile and recalcitrant C, contributing to an observed 24% increase in 2010 growing season and 56% increase of decomposition of a standard substrate, but also functional genes for anaerobic processes (e.g., denitrification, sulfate reduction, methanogenesis). Further comparisons by shotgun sequencing showed significant differences of microbial community structure between AK and OK sites. The OK site was enriched in genes annotated for cellulose degradation, CO2 production, denitrification, sporulation, heat shock response, and cellular surface structures (e.g., trans-membrane transporters for glucosides), while the AK warmed plots were enriched in metabolic pathways related to labile C decomposition. Together, our results demonstrate the vulnerability of permafrost ecosystem C to climate warming and the importance of microbial feedbacks in mediating such vulnerability.

The fabrication and visible-near-infrared optical modulation of vanadium dioxide/silicon dioxide composite photonic crystal structure

NASA Astrophysics Data System (ADS)

Liang, Jiran; Li, Peng; Song, Xiaolong; Zhou, Liwei

2017-12-01

We demonstrated a visible and near-infrared light tunable photonic nanostructure, which is composed of vanadium dioxide (VO2) thin film and silicon dioxide (SiO2) ordered nanosphere arrays. The vanadium films were sputtered on two-dimensional (2D) SiO2 sphere arrays. VO2 thin films were prepared by rapid thermal annealing (RTA) method with different oxygen flow rates. The close-packed VO2 shell formed a continuous surface, the composition of VO2 films in the structure changed when the oxygen flow rates increased. The 2D VO2/SiO2 composite photonic crystal structure exhibited transmittance trough tunability and near-infrared (NIR) transmittance modulation. When the oxygen flow rate increased from 3 slpm to 4 slpm, the largest transmittance trough can be regulated from 904 to 929 nm at low temperature, the transmittance troughs also appear blue shift when the VO2 phase changes from insulator to metal. The composite nanostructure based on VO2 films showed visible transmittance tunability, which would provide insights into the glass color changing in smart windows.

Interactions between Snow Chemistry, Mercury Inputs and Microbial Population Dynamics in an Arctic Snowpack

PubMed Central

Larose, Catherine; Prestat, Emmanuel; Cecillon, Sébastien; Berger, Sibel; Malandain, Cédric; Lyon, Delina; Ferrari, Christophe; Schneider, Dominique; Dommergue, Aurélien; Vogel, Timothy M.

2013-01-01

We investigated the interactions between snowpack chemistry, mercury (Hg) contamination and microbial community structure and function in Arctic snow. Snowpack chemistry (inorganic and organic ions) including mercury (Hg) speciation was studied in samples collected during a two-month field study in a high Arctic site, Svalbard, Norway (79°N). Shifts in microbial community structure were determined by using a 16S rRNA gene phylogenetic microarray. We linked snowpack and meltwater chemistry to changes in microbial community structure by using co-inertia analyses (CIA) and explored changes in community function due to Hg contamination by q-PCR quantification of Hg-resistance genes in metagenomic samples. Based on the CIA, chemical and microbial data were linked (p = 0.006) with bioavailable Hg (BioHg) and methylmercury (MeHg) contributing significantly to the ordination of samples. Mercury was shown to influence community function with increases in merA gene copy numbers at low BioHg levels. Our results show that snowpacks can be considered as dynamic habitats with microbial and chemical components responding rapidly to environmental changes. PMID:24282515

Seasonal changes in infaunal community structure in a hypertrophic brackish canal: Effects of hypoxia, sulfide, and predator-prey interaction.

PubMed

Kanaya, Gen; Nakamura, Yasuo; Koizumi, Tomoyoshi; Yamada, Katsumasa

2015-07-01

We conducted a one-year survey of macrozoobenthic community structure at 5 stations in a eutrophic canal in inner Tokyo Bay, focusing on the impacts of hypoxia, sediment H2S, and species interaction in the littoral soft-bottom habitats. Complete defaunation or decreasing density of less-tolerant taxa occurred under hypoxia during warmer months, especially at subtidal or sulfidic stations; this was followed by rapid recolonization by opportunistic polychaetes in fall-winter. Sedimentary H2S increased the mortality of macroinvertebrates under hypoxia or delayed population recovery during recolonization. The density of several polychaetes (e.g., Pseudopolydora reticulata) declined in winter, coincident with immigration of the predator Armandia lanceolata. This suggests that absence of A. lanceolata under moderate hypoxia enabled the proliferation of prey taxa. We conclude that oxygen concentration, sediment H2S, and hypoxia-induced changes in species interactions are potential drivers for spatiotemporal changes in macrozoobenthic assemblage structure in hypoxia-prone soft-bottom communities. Copyright © 2015 Elsevier Ltd. All rights reserved.

A comparison of methods to assess long-term changes in Sonoran Desert vegetation

USGS Publications Warehouse

Munson, S.M.; Webb, R.H.; Hubbard, J.A.

2011-01-01

Knowledge about the condition of vegetation cover and composition is critical for assessing the structure and function of ecosystems. To effectively quantify the impacts of a rapidly changing environment, methods to track long-term trends of vegetation must be precise, repeatable, and time- and cost-efficient. Measuring vegetation cover and composition in arid and semiarid regions is especially challenging because vegetation is typically sparse, discontinuous, and individual plants are widely spaced. To meet the goal of long-term vegetation monitoring in the Sonoran Desert and other arid and semiarid regions, we determined how estimates of plant species, total vegetation, and soil cover obtained using a widely-implemented monitoring protocol compared to a more time- and resource-intensive plant census. We also assessed how well this protocol tracked changes in cover through 82 years compared to the plant census. Results from the monitoring protocol were comparable to those from the plant census, despite low and variable plant species cover. Importantly, this monitoring protocol could be used as a rapid, "off-the shelf" tool for assessing land degradation (or desertification) in arid and semiarid ecosystems.

The perception of geometrical structure from congruence

NASA Technical Reports Server (NTRS)

Lappin, Joseph S.; Wason, Thomas D.

1989-01-01

The principle function of vision is to measure the environment. As demonstrated by the coordination of motor actions with the positions and trajectories of moving objects in cluttered environments and by rapid recognition of solid objects in varying contexts from changing perspectives, vision provides real-time information about the geometrical structure and location of environmental objects and events. The geometric information provided by 2-D spatial displays is examined. It is proposed that the geometry of this information is best understood not within the traditional framework of perspective trigonometry, but in terms of the structure of qualitative relations defined by congruences among intrinsic geometric relations in images of surfaces. The basic concepts of this geometrical theory are outlined.

Evolution of crystallins for a role in the vertebrate eye lens.

PubMed

Slingsby, Christine; Wistow, Graeme J; Clark, Alice R

2013-04-01

The camera eye lens of vertebrates is a classic example of the re-engineering of existing protein components to fashion a new device. The bulk of the lens is formed from proteins belonging to two superfamilies, the α-crystallins and the βγ-crystallins. Tracing their ancestry may throw light on the origin of the optics of the lens. The α-crystallins belong to the ubiquitous small heat shock proteins family that plays a protective role in cellular homeostasis. They form enormous polydisperse oligomers that challenge modern biophysical methods to uncover the molecular basis of their assembly structure and chaperone-like protein binding function. It is argued that a molecular phenotype of a dynamic assembly suits a chaperone function as well as a structural role in the eye lens where the constraint of preventing protein condensation is paramount. The main cellular partners of α-crystallins, the β- and γ-crystallins, have largely been lost from the animal kingdom but the superfamily is hugely expanded in the vertebrate eye lens. Their structures show how a simple Greek key motif can evolve rapidly to form a complex array of monomers and oligomers. Apart from remaining transparent, a major role of the partnership of α-crystallins with β- and γ-crystallins in the lens is to form a refractive index gradient. Here, we show some of the structural and genetic features of these two protein superfamilies that enable the rapid creation of different assembly states, to match the rapidly changing optical needs among the various vertebrates. Copyright © 2013 The Protein Society.

Evolution of crystallins for a role in the vertebrate eye lens

PubMed Central

Slingsby, Christine; Wistow, Graeme J; Clark, Alice R

2013-01-01

The camera eye lens of vertebrates is a classic example of the re-engineering of existing protein components to fashion a new device. The bulk of the lens is formed from proteins belonging to two superfamilies, the α-crystallins and the βγ-crystallins. Tracing their ancestry may throw light on the origin of the optics of the lens. The α-crystallins belong to the ubiquitous small heat shock proteins family that plays a protective role in cellular homeostasis. They form enormous polydisperse oligomers that challenge modern biophysical methods to uncover the molecular basis of their assembly structure and chaperone-like protein binding function. It is argued that a molecular phenotype of a dynamic assembly suits a chaperone function as well as a structural role in the eye lens where the constraint of preventing protein condensation is paramount. The main cellular partners of α-crystallins, the β- and γ-crystallins, have largely been lost from the animal kingdom but the superfamily is hugely expanded in the vertebrate eye lens. Their structures show how a simple Greek key motif can evolve rapidly to form a complex array of monomers and oligomers. Apart from remaining transparent, a major role of the partnership of α-crystallins with β- and γ-crystallins in the lens is to form a refractive index gradient. Here, we show some of the structural and genetic features of these two protein superfamilies that enable the rapid creation of different assembly states, to match the rapidly changing optical needs among the various vertebrates. PMID:23389822

Changes in tundra pond limnology: re-sampling Alaskan ponds after 40 years.

PubMed

Lougheed, Vanessa L; Butler, Malcolm G; McEwen, Daniel C; Hobbie, John E

2011-09-01

The arctic tundra ponds at the International Biological Program (IBP) site in Barrow, AK, were studied extensively in the 1970s; however, very little aquatic research has been conducted there for over three decades. Due to the rapid climate changes already occurring in northern Alaska, identifying any changes in the ponds' structure and function over the past 30-40 years can help identify any potential climate-related impacts. Current research on the IBP ponds has revealed significant changes in the physical, chemical, and biological characteristics of these ponds over time. These changes include increased water temperatures, increased water column nutrient concentrations, the presence of at least one new chironomid species, and increased macrophyte cover. However, we have also observed significant annual variation in many measured variables and caution that this variation must be taken into account when attempting to make statements about longer-term change. The Barrow IBP tundra ponds represent one of the very few locations in the Arctic where long-term data are available on freshwater ecosystem structure and function. Continued monitoring and protection of these invaluable sites is required to help understand the implications of climate change on freshwater ecosystems in the Arctic.

Theoretical calculations of high-pressure phases of NiF2: An ab initio constant-pressure study

NASA Astrophysics Data System (ADS)

Kürkçü, Cihan; Merdan, Ziya; Öztürk, Hülya

2016-12-01

We have studied the structural properties of the antiferromagnetic NiF2 tetragonal structure with P42/ mnm symmetry using density functional theory (DFT) under rapid hydrostatic pressure up to 400 GPa. For the exchange correlation energy we used the local density approximation (LDA) of Ceperley and Alder (CA). Two phase transformations are successfully observed through the simulations. The structures of XF2-type compounds crystallize in rutile-type structure. NiF2 undergoes phase transformations from the tetragonal rutile-type structure with space group P42/ mnm to orthorhombic CaCl2-type structure with space group Pnnm and from this orthorhombic phase to monoclinic structure with space group C2/ m at 152 GPa and 360 GPa, respectively. These phase changes are also studied by total energy and enthalpy calculations. According to these calculations, we perdict these phase transformations at about 1.85 and 30 GPa.

Body shape transformation along a shared axis of anatomical evolution in labyrinth fishes (Anabantoidei).

PubMed

Collar, David C; Quintero, Michelle; Buttler, Bernardo; Ward, Andrea B; Mehta, Rita S

2016-03-01

Major morphological transformations, such as the evolution of elongate body shape in vertebrates, punctuate evolutionary history. A fundamental step in understanding the processes that give rise to such transformations is identification of the underlying anatomical changes. But as we demonstrate in this study, important insights can also be gained by comparing these changes to those that occur in ancestral and closely related lineages. In labyrinth fishes (Anabantoidei), rapid evolution of a highly derived torpedo-shaped body in the common ancestor of the pikehead (Luciocephalus aura and L. pulcher) occurred primarily through exceptional elongation of the head, with secondary contributions involving reduction in body depth and lengthening of the precaudal vertebral region. This combination of changes aligns closely with the primary axis of anatomical diversification in other anabantoids, revealing that pikehead evolution involved extraordinarily rapid change in structures that were ancestrally labile. Finer-scale examination of the anatomical components that determine head elongation also shows alignment between the pikehead evolutionary trajectory and the primary axis of cranial diversification in anabantoids, with much higher evolutionary rates leading to the pikehead. Altogether, our results show major morphological transformation stemming from extreme change along a shared morphological axis in labyrinth fishes. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Extent and ecological consequences of hunting in Central African rainforests in the twenty-first century

PubMed Central

Abernethy, K. A.; Coad, L.; Taylor, G.; Lee, M. E.; Maisels, F.

2013-01-01

Humans have hunted wildlife in Central Africa for millennia. Today, however, many species are being rapidly extirpated and sanctuaries for wildlife are dwindling. Almost all Central Africa's forests are now accessible to hunters. Drastic declines of large mammals have been caused in the past 20 years by the commercial trade for meat or ivory. We review a growing body of empirical data which shows that trophic webs are significantly disrupted in the region, with knock-on effects for other ecological functions, including seed dispersal and forest regeneration. Plausible scenarios for land-use change indicate that increasing extraction pressure on Central African forests is likely to usher in new worker populations and to intensify the hunting impacts and trophic cascade disruption already in progress, unless serious efforts are made for hunting regulation. The profound ecological changes initiated by hunting will not mitigate and may even exacerbate the predicted effects of climate change for the region. We hypothesize that, in the near future, the trophic changes brought about by hunting will have a larger and more rapid impact on Central African rainforest structure and function than the direct impacts of climate change on the vegetation. Immediate hunting regulation is vital for the survival of the Central African rainforest ecosystem. PMID:23878333

Extent and ecological consequences of hunting in Central African rainforests in the twenty-first century.

PubMed

Abernethy, K A; Coad, L; Taylor, G; Lee, M E; Maisels, F

2013-01-01

Humans have hunted wildlife in Central Africa for millennia. Today, however, many species are being rapidly extirpated and sanctuaries for wildlife are dwindling. Almost all Central Africa's forests are now accessible to hunters. Drastic declines of large mammals have been caused in the past 20 years by the commercial trade for meat or ivory. We review a growing body of empirical data which shows that trophic webs are significantly disrupted in the region, with knock-on effects for other ecological functions, including seed dispersal and forest regeneration. Plausible scenarios for land-use change indicate that increasing extraction pressure on Central African forests is likely to usher in new worker populations and to intensify the hunting impacts and trophic cascade disruption already in progress, unless serious efforts are made for hunting regulation. The profound ecological changes initiated by hunting will not mitigate and may even exacerbate the predicted effects of climate change for the region. We hypothesize that, in the near future, the trophic changes brought about by hunting will have a larger and more rapid impact on Central African rainforest structure and function than the direct impacts of climate change on the vegetation. Immediate hunting regulation is vital for the survival of the Central African rainforest ecosystem.

Numerical analysis of exhaust jet secondary combustion in hypersonic flow field

NASA Astrophysics Data System (ADS)

Yang, Tian-Peng; Wang, Jiang-Feng; Zhao, Fa-Ming; Fan, Xiao-Feng; Wang, Yu-Han

2018-05-01

The interaction effect between jet and control surface in supersonic and hypersonic flow is one of the key problems for advanced flight control system. The flow properties of exhaust jet secondary combustion in a hypersonic compression ramp flow field were studied numerically by solving the Navier-Stokes equations with multi-species and combustion reaction effects. The analysis was focused on the flow field structure and the force amplification factor under different jet conditions. Numerical results show that a series of different secondary combustion makes the flow field structure change regularly, and the temperature increases rapidly near the jet exit.

Change and Stability in the Characteristics of Homicide Victims, Offenders and Incidents During Rapid Social Change

PubMed Central

Pridemore, William Alex

2008-01-01

The Russian homicide rate doubled during the 1990s and is now among the highest in the world. During this same period, Russian citizens experienced swift, widespread, and meaningful political, economic, and social change. It is likely that this profound transition altered structural conditions, cultural norms, and interpersonal relations in a way that led to changes in the nature of interpersonal violence. Taking advantage of a unique set of homicide narratives drawn from court and police records in the Udmurt Republic, this study examined stability and change in the distribution of Russian homicide victim, offender, and incident characteristics before and after the fall of the Soviet Union. Odds ratios obtained from logistic regression showed no change in victim characteristics, but substantial changes in several offender and incident characteristics. We discuss the potential mechanisms through which the structural and cultural shifts are resulting in these changes and conclude that the ongoing transition is largely responsible for the changing nature of homicide in Russia. In doing so, we introduce the new term “criminological transition” and suggest that Russia (and perhaps other nations) may have experienced a change in its crime profile in much the same way as we discuss a “demographic transition” in terms of fertility and mortality profiles. PMID:19122789

SCATS: SRB Cost Accounting and Tracking System handbook

NASA Technical Reports Server (NTRS)

Zorv, R. B.; Stewart, R. D.; Coley, G.; Higginbotham, M.

1978-01-01

The Solid Rocket Booster Cost Accounting and Tracking System (SCATS) which is an automatic data processing system designed to keep a running account of the number, description, and estimated cost of Level 2, 3, and 4 changes is described. Although designed specifically for the Space Shuttle Solid Rocket Booster Program, the ADP system can be used for any other program that has a similar structure for recording, reporting, and summing numbers and costs of changes. The program stores the alpha-numeric designators for changes, government estimated costs, proposed costs, and negotiated value in a MIRADS (Marshall Information Retrieval and Display System) format which permits rapid access, manipulation, and reporting of current change status. Output reports listing all changes, totals of each level, and totals of all levels, can be derived for any calendar interval period.

Hydrocarbon traps within a seismic sequence framework, Stevens turbidites, southern San Joaquin Valley, CA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hewlett, J.S.; Jordan, D.W.; Crebs, T.J.

1991-02-01

Interpretation of the seismic sequence framework and log and lithologic character of upper Miocene Stevens turbidites on the Bakersfield arch has led to an improved understanding of the expression of stratigraphic trapping that should reduce exploration risk in the basin, and may aid exploration efforts in similar sand-rich systems globally. These deepwater sandstones are contained within three lowstand turbidite systems (LTS) that were deposited in a narrow deepwater basin adjacent to the ancestral Sierra Nevada. the oldest LTS, the Coulter, was transported through several submarine canyons incised into the Fruitvale Shale. In contrast, numerous smaller scale erosional features located onmore » the high-relief slopes of the highstand Santa Margarita deltas, fed the overlying Gosford and Bellevue LTS. The systems consist of sandy, high-density (primarily) and low-density turbidites that were deposited within channel-lobe complexes. On the arch, 472 MMBO and 1.3 tcf have been produced from four seismically detectable traps with strong stratigraphic components: (1) sandstone permeability changes within turbidite wedges that thin rapidly onto structure (2) confined (channelized) turbidites that lap out on a structure (e.g., F-1 sand, South Coles levee), (3) channelized turbidites that pinch out within slope gullies, and (4) depositional compaction anticlines occurring in conjunction with low-gradient regional structure. Condensed section sediments form regional and reservoir-scale seals. Rapid lateral facies changes and grain size variations provide additional seal facies.« less

Pattern changes in determinants of Chinese emissions

NASA Astrophysics Data System (ADS)

Mi, Zhifu; Meng, Jing; Guan, Dabo; Shan, Yuli; Liu, Zhu; Wang, Yutao; Feng, Kuishuang; Wei, Yi-Ming

2017-07-01

The Chinese economy has been recovering slowly from the global financial crisis, but it cannot achieve the same rapid development of the pre-recession period. Instead, the country has entered a new phase of economic development—a ‘new normal’. We use a structural decomposition analysis and environmental input-output analysis to estimate the determinants of China’s carbon emission changes during 2005-2012. China’s imports are linked to a global multi-regional input-output model based on the Global Trade and Analysis Project database to calculate the embodied CO2 emissions in imports. We find that the global financial crisis has affected the drivers of China’s carbon emission growth. From 2007 to 2010, the CO2 emissions induced by China’s exports dropped, whereas emissions induced by capital formation grew rapidly. In the ‘new normal’, the strongest factors that offset CO2 emissions have shifted from efficiency gains to structural upgrading. Efficiency was the strongest factor offsetting China’s CO2 emissions before 2010 but drove a 1.4% increase in emissions in the period 2010-2012. By contrast, production structure and consumption patterns caused a 2.6% and 1.3% decrease, respectively, in China’s carbon emissions from 2010 to 2012. In addition, China tends to shift gradually from an investment to a consumption-driven economy. The proportion of CO2 emissions induced by consumption had a declining trend before 2010 but grew from 28.6%-29.1% during 2010-2012.

Application of electrospray ionization hybrid ion trap/time-of-flight mass spectrometry in the rapid characterization of quinocetone metabolites formed in vitro.

PubMed

Liu, Zhao-Ying; Huang, Ling-Li; Chen, Dong-Mei; Dai, Meng-Hong; Tao, Yan-Fei; Wang, Yu-Lian; Yuan, Zong-Hui

2010-02-01

The application of electrospray ionization hybrid ion trap/time-of-flight mass spectrometry coupled with high-performance liquid chromatography (LC/MS-IT-TOF) in the rapid characterization of in vitro metabolites of quinocetone was developed. Metabolites formed in rat liver microsomes were separated using a VP-ODS column with gradient elution. Multiple scans of metabolites in MS and MS(2) modes and accurate mass measurements were automatically performed simultaneously through data-dependent acquisition in only a 30-min analysis. Most measured mass errors were less than 10 ppm for both protonated molecules and fragment ions using external mass calibration. The elemental compositions of all fragment ions of quinocetone and its metabolites could be rapidly assigned based upon the known compositional elements of protonated molecules. The structure of metabolites were elucidated based on the combination of three techniques: agreement between their proposed structure, the accurate masses, and the elemental composition of ions in their mass spectra; comparison of their changes in accurate molecular masses and fragment ions with those of parent drug or metabolite; and the elemental compositions of lost mass numbers in proposed fragmentation pathways. Twenty-seven phase I metabolites were identified as 11 reduction metabolites, three direct hydroxylation metabolites, and 13 metabolites with a combination of reduction and hydroxylation. All metabolites except the N-oxide reduction metabolite M6 are new metabolites of quinocetone, which were not previously reported. The ability to conduct expected biotransformation profiling via tandem mass spectrometry coupled with accurate mass measurement, all in a single experimental run, is one of the most attractive features of this methodology. The results demonstrate the use of LC/MS-IT-TOF approach appears to be rapid, efficient, and reliable in structural characterization of drug metabolites.

Hospital consolidation outlook: surviving in a tough economy.

PubMed

Myers, Chris; Lineen, Jason

2009-11-01

The rapid hospital consolidation activity of the late 1990s has tapered off, but it's expected to pick up again. The reasons for hospital consolidation have shifted from gaining leverage with payers to achieving cost savings and operating efficiencies to survive in the market. The hospital industry can expect to undergo more profound structural and organizational changes in the decade ahead than it did in the past decade.

Hemlock declines rapidly with hemlock woolly adelgid infestation: impacts on the carbon cycle of the Southern Appalachian forests

Treesearch

April E. Nuckolls; Nina Wurzburger; Chelcy R. Ford; Ronald L. Hendrick; James M. Vose; Brian D. Kloeppel

2008-01-01

The recent infestation of southern Appalachian eastern hemlock stands by hemlock woolly adelgid (HWA) is expected to have dramatic and lasting effects on forest structure and function. We studied the short-term changes to the carbon cycle in a mixed stand of hemlock and hardwoods, where hemlock was declining due to either girdling or HWA infestation. We expected that...

Conversion of Military Industry to Civilian Production in the USSR

DTIC Science & Technology

1992-01-10

dustry designed to support great power policies . In the face of the rapidly deteriorating economy, republican governments are seek- ing resources with...Investment in the Defense Sector . . 129 7.2 Restructuring of the Conversion Policy . . . . 132 .7.3 Change the institutional structure of adminis- tration for...Implications for the U.S. policies . . 217 2.3 The transformation of the military industry’s administrative apparatus. . . . . . . . . . 218 2.3.1

Interferometry in the era of time-domain astronomy

NASA Astrophysics Data System (ADS)

Schaefer, Gail H.; Cassan, Arnaud; Gallenne, Alexandre; Roettenbacher, Rachael M.; Schneider, Jean

2018-04-01

The physical nature of time variable objects is often inferred from photometric light-curves and spectroscopic variations. Long-baseline optical interferometry has the power to resolve the spatial structure of time variable sources directly in order to measure their physical properties and test the physics of the underlying models. Recent interferometric studies of variable objects include measuring the angular expansion and spatial structure during the early stages of novae outbursts, studying the transits and tidal distortions of the components in eclipsing and interacting binaries, measuring the radial pulsations in Cepheid variables, monitoring changes in the circumstellar discs around rapidly rotating massive stars, and imaging starspots. Future applications include measuring the image size and centroid displacements in gravitational microlensing events, and imaging the transits of exoplanets. Ongoing and upcoming photometric surveys will dramatically increase the number of time-variable objects detected each year, providing many potential targets to observe interferometrically. For short-lived transient events, it is critical for interferometric arrays to have the flexibility to respond rapidly to targets of opportunity and optimize the selection of baselines and beam combiners to provide the necessary resolution and sensitivity to resolve the source as its brightness and size change. We discuss the science opportunities made possible by resolving variable sources using long baseline optical interferometry.

Rapid transition in the structure of a coral reef community: the effects of coral bleaching and physical disturbance.

PubMed

Ostrander, G K; Armstrong, K M; Knobbe, E T; Gerace, D; Scully, E P

2000-05-09

Coral reef communities are in a state of change throughout their geographical range. Factors contributing to this change include bleaching (the loss of algal symbionts), storm damage, disease, and increasing abundance of macroalgae. An additional factor for Caribbean reefs is the aftereffects of the epizootic that reduced the abundance of the herbivorous sea urchin, Diadema antillarum. Although coral reef communities have undergone phase shifts, there are few studies that document the details of such transitions. We report the results of a 40-month study that documents changes in a Caribbean reef community affected by bleaching, hurricane damage, and an increasing abundance of macroalgae. The study site was in a relatively pristine area of the reef surrounding the island of San Salvador in the Bahamas. Ten transects were sampled every 3-9 months from November 1994 to February 1998. During this period, the corals experienced a massive bleaching event resulting in a significant decline in coral abundance. Algae, especially macroalgae, increased in abundance until they effectively dominated the substrate. The direct impact of Hurricane Lili in October 1996 did not alter the developing community structure and may have facilitated increasing algal abundance. The results of this study document the rapid transition of this reef community from one in which corals and algae were codominant to a community dominated by macroalgae. The relatively brief time period required for this transition illustrates the dynamic nature of reef communities.

Rapid fluctuations in extracellular brain glucose levels induced by natural arousing stimuli and intravenous cocaine: fueling the brain during neural activation

PubMed Central

Lenoir, Magalie

2012-01-01

Glucose, a primary energetic substrate for neural activity, is continuously influenced by two opposing forces that tend to either decrease its extracellular levels due to enhanced utilization in neural cells or increase its levels due to entry from peripheral circulation via enhanced cerebral blood flow. How this balance is maintained under physiological conditions and changed during neural activation remains unclear. To clarify this issue, enzyme-based glucose sensors coupled with high-speed amperometry were used in freely moving rats to evaluate fluctuations in extracellular glucose levels induced by brief audio stimulus, tail pinch (TP), social interaction with another rat (SI), and intravenous cocaine (1 mg/kg). Measurements were performed in nucleus accumbens (NAcc) and substantia nigra pars reticulata (SNr), which drastically differ in neuronal activity. In NAcc, where most cells are powerfully excited after salient stimulation, glucose levels rapidly (latency 2–6 s) increased (30–70 μM or 6–14% over baseline) by all stimuli; the increase differed in magnitude and duration for each stimulus. In SNr, where most cells are transiently inhibited by salient stimuli, TP, SI, and cocaine induced a biphasic glucose response, with the initial decrease (−20–40 μM or 5–10% below baseline) followed by a reboundlike increase. The critical role of neuronal activity in mediating the initial glucose response was confirmed by monitoring glucose currents after local microinjections of glutamate (GLU) or procaine (PRO). While intra-NAcc injection of GLU transiently increased glucose levels in this structure, intra-SNr PRO injection resulted in rapid, transient decreases in SNr glucose. Therefore, extracellular glucose levels in the brain change very rapidly after physiological and pharmacological stimulation, the response is structure specific, and the pattern of neuronal activity appears to be a critical factor determining direction and magnitude of physiological fluctuations in glucose levels. PMID:22723672

Irregularity, volatility, risk, and financial market time series

PubMed Central

Pincus, Steve; Kalman, Rudolf E.

2004-01-01

The need to assess subtle, potentially exploitable changes in serial structure is paramount in the analysis of financial data. Herein, we demonstrate the utility of approximate entropy (ApEn), a model-independent measure of sequential irregularity, toward this goal, by several distinct applications. We consider both empirical data and models, including composite indices (Standard and Poor's 500 and Hang Seng), individual stock prices, the random-walk hypothesis, and the Black–Scholes and fractional Brownian motion models. Notably, ApEn appears to be a potentially useful marker of system stability, with rapid increases possibly foreshadowing significant changes in a financial variable. PMID:15358860

Structural and Maturational Covariance in Early Childhood Brain Development.

PubMed

Geng, Xiujuan; Li, Gang; Lu, Zhaohua; Gao, Wei; Wang, Li; Shen, Dinggang; Zhu, Hongtu; Gilmore, John H

2017-03-01

Brain structural covariance networks (SCNs) composed of regions with correlated variation are altered in neuropsychiatric disease and change with age. Little is known about the development of SCNs in early childhood, a period of rapid cortical growth. We investigated the development of structural and maturational covariance networks, including default, dorsal attention, primary visual and sensorimotor networks in a longitudinal population of 118 children after birth to 2 years old and compared them with intrinsic functional connectivity networks. We found that structural covariance of all networks exhibit strong correlations mostly limited to their seed regions. By Age 2, default and dorsal attention structural networks are much less distributed compared with their functional maps. The maturational covariance maps, however, revealed significant couplings in rates of change between distributed regions, which partially recapitulate their functional networks. The structural and maturational covariance of the primary visual and sensorimotor networks shows similar patterns to the corresponding functional networks. Results indicate that functional networks are in place prior to structural networks, that correlated structural patterns in adult may arise in part from coordinated cortical maturation, and that regional co-activation in functional networks may guide and refine the maturation of SCNs over childhood development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Plant-based Food and Feed Protein Structure Changes Induced by Gene-transformation heating and bio-ethanol processing: A Synchrotron-based Molecular Structure and Nutrition Research Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

P Yu

Unlike traditional 'wet' analytical methods which during processing for analysis often result in destruction or alteration of the intrinsic protein structures, advanced synchrotron radiation-based Fourier transform infrared microspectroscopy has been developed as a rapid and nondestructive and bioanalytical technique. This cutting-edge synchrotron-based bioanalytical technology, taking advantages of synchrotron light brightness (million times brighter than sun), is capable of exploring the molecular chemistry or structure of a biological tissue without destruction inherent structures at ultra-spatial resolutions. In this article, a novel approach is introduced to show the potential of the advanced synchrotron-based analytical technology, which can be used to study plant-basedmore » food or feed protein molecular structure in relation to nutrient utilization and availability. Recent progress was reported on using synchrotron-based bioanalytical technique synchrotron radiation-based Fourier transform infrared microspectroscopy and diffused reflectance infrared Fourier transform spectroscopy to detect the effects of gene-transformation (Application 1), autoclaving (Application 2), and bio-ethanol processing (Application 3) on plant-based food and feed protein structure changes on a molecular basis. The synchrotron-based technology provides a new approach for plant-based protein structure research at ultra-spatial resolutions at cellular and molecular levels.« less

Effects of Clonal Reproduction on Evolutionary Lag and Evolutionary Rescue.

PubMed

Orive, Maria E; Barfield, Michael; Fernandez, Carlos; Holt, Robert D

2017-10-01

Evolutionary lag-the difference between mean and optimal phenotype in the current environment-is of keen interest in light of rapid environmental change. Many ecologically important organisms have life histories that include stage structure and both sexual and clonal reproduction, yet how stage structure and clonality interplay to govern a population's rate of evolution and evolutionary lag is unknown. Effects of clonal reproduction on mean phenotype partition into two portions: one that is phenotype dependent, and another that is genotype dependent. This partitioning is governed by the association between the nonadditive genetic plus random environmental component of phenotype of clonal offspring and their parents. While clonality slows phenotypic evolution toward an optimum, it can dramatically increase population survival after a sudden step change in optimal phenotype. Increased adult survival slows phenotypic evolution but facilitates population survival after a step change; this positive effect can, however, be lost given survival-fecundity trade-offs. Simulations indicate that the benefits of increased clonality under environmental change greatly depend on the nature of that change: increasing population persistence under a step change while decreasing population persistence under a continuous linear change requiring de novo variation. The impact of clonality on the probability of persistence for species in a changing world is thus inexorably linked to the temporal texture of the change they experience.

Mount Etna: 3-D and 4-D structure using seismic tomography

NASA Astrophysics Data System (ADS)

Nunn, C.; Julian, B. R.; Foulger, G. R.; Patanè, D.; Ibáñez, J. M.; Briole, P.; Mhanna, N.

2015-12-01

We investigate the time-varying structure of Etna, an active stratovolcano in eastern Sicily, using seismic tomography. In volcanic systems, it is thought that the presence of fluids, cracks and pressurized gases can rapidly and drastically change the elastic properties of the host rocks. Recent work suggests that changes beneath Etna are detectable with seismic methods, and that these changes can be linked to volcanic activity. Temporal changes to Earth structure are commonly investigated by carrying out separate tomographic inversions for different epochs. However, repeated inversions of the same area are expected to vary, even if the structure itself does not change. This is due to variations in the seismic ray distribution and to observational errors. Potentially, changes between epochs which are due to experimental limitations can be misinterpreted as changes to the structure of the volcano. Consequently, we use a new tomographic program, TOMO4D, that inverts multiple data sets simultaneously [Julian & Foulger, Time-dependent seismic tomography, GJI, 2010]. This code imposes constraints which minimise the differences calculated between two epochs. The remaining structural variations are thus truly required to fit the data, and reflect changes which almost certainly exist between the two epochs. We have selected and relocated ~400 local earthquakes with at least 5 P and 5 S observations. They cover a period which includes several eruptions, from 1st November 2000 to 31st December 2006. We divide our data into different epochs and invert two epochs simultaneously. The models show a seismically fast central region, surrounded by a slower outer region. This suggests a central system of dykes or sills surrounded by volcanic sediments and country rock. At depths of 0-4 km below sea level the seismically fast region is not below the summit crater but is offset to the southwest. By monitoring the changes to the elastic parameters of the host rocks we observe temporal changes within the volcano. The technique has potential for long-term volcano monitoring and hazard assessment since it could be applied to monitoring changes from month to month.

Rapid fluctuations in the northern Baltic Sea H2S layer

NASA Astrophysics Data System (ADS)

Kankaanpää, Harri T.; Virtasalo, Joonas J.

2017-12-01

Hydrogen sulfide (H2S) is linked to water quality deterioration in the Baltic Sea, with widespread seafloor hypoxia. We examined the vertical and temporal variability of in situ [H2S], oxygen concentration ([O2]), temperature (T) and pH at weekly, hourly and minute intervals at 13 locations in the western Gulf of Finland in 2013-2014. The main target was the 60-100 m water depth range, containing 3.2-290 μM O2 and 6.3-22.6 μM H2S. Where gas was detected by acoustic surveys, the structure of the H2S layer was more complex compared to stations devoid of gas. Local minima and maxima in pH frequently occurred near the H2S upper boundary (redox transition zone). Except for the homogeneous, tranquil zone above the seafloor at some stations, substantial rapid changes in hydrographic conditions were common. Typically, a layer of marked temporal T variability was present atop or within the topmost H2S layers. The largest temporal changes over a weekly period were - 0.44 °C/- 10.8 μM H2S/- 0.12 pH units (at seafloor level), + 0.18 °C/+7.9 μM H2S between casts (1 h) and + 0.03 °C/- 2.5 μM H2S per minute (high resolution logging). Abrupt [H2S] changes were recorded at two stations with sediments containing free gas. The T and [H2S] changes were synchronous at several layers, reflecting water movement. We conclude that rapid changes occur in hydrographic conditions in the near-bottom H2S layer in the northern Baltic Sea, especially at locations where free gas is present in the underlying sediments.

In silico evolution of biochemical networks

NASA Astrophysics Data System (ADS)

Francois, Paul

2010-03-01

We use computational evolution to select models of genetic networks that can be built from a predefined set of parts to achieve a certain behavior. Selection is made with the help of a fitness defining biological functions in a quantitative way. This fitness has to be specific to a process, but general enough to find processes common to many species. Computational evolution favors models that can be built by incremental improvements in fitness rather than via multiple neutral steps or transitions through less fit intermediates. With the help of these simulations, we propose a kinetic view of evolution, where networks are rapidly selected along a fitness gradient. This mathematics recapitulates Darwin's original insight that small changes in fitness can rapidly lead to the evolution of complex structures such as the eye, and explain the phenomenon of convergent/parallel evolution of similar structures in independent lineages. We will illustrate these ideas with networks implicated in embryonic development and patterning of vertebrates and primitive insects.

Comparative Analysis of Binding Kinetics and Thermodynamics of Dipeptidyl Peptidase-4 Inhibitors and Their Relationship to Structure.

PubMed

Schnapp, Gisela; Klein, Thomas; Hoevels, Yvette; Bakker, Remko A; Nar, Herbert

2016-08-25

The binding kinetics and thermodynamics of dipeptidyl peptidase (DPP)-4 inhibitors (gliptins) were investigated using surface plasmon resonance and isothermal titration calorimetry. Binding of gliptins to DPP-4 is a rapid electrostatically driven process. Off-rates were generally slow partly because of reversible covalent bond formation by some gliptins, and partly because of strong and extensive interactions. Binding of all gliptins is enthalpy-dominated due to strong ionic interactions and strong solvent-shielded hydrogen bonds. Using a congeneric series of molecules which represented the intermediates in the lead optimization program of linagliptin, the onset of slow binding kinetics and development of the thermodynamic repertoire were analyzed in the context of incremental changes of the chemical structures. All compounds rapidly associated, and therefore the optimization of affinity and residence time is highly correlated. The major contributor to the increasing free energy of binding was a strong increase of binding enthalpy, whereas entropic contributions remained low and constant despite significant addition of lipophilicity.

Understanding barotrauma in fish passing hydro structures: a global strategy for sustainable development of water resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Richard S.; Colotelo, Alison HA; Pflugrath, Brett D.

2014-03-24

Freshwater fishes are one of the most imperiled groups of vertebrates and species declines have been linked to a number of anthropogenic influences. This is alarming as the diversity and stability of populations are at risk. In addition, freshwater fish serve as important protein sources, particularly in developing countries. One of the focal activities thought to influence freshwater fish population declines is water resource development, which is anticipated to increase over the next several decades. For fish encountering hydro structures, such as passing through hydroturbines, there may be a rapid decrease in pressure which can lead to injuries commonly referredmore » to as barotraumas. The authors summarize the research to date that has examined the effects of rapid pressure changes on fish and outline the most important factors to consider (i.e., swim bladder morphology, depth of acclimation, migration pattern and life stage) when examining the susceptibility of barotraumas for fish of interest.« less

Role of Hf on Phase Formation in Ti45Zr(38-x)Hf(x)Ni17 Liquids and Solids

NASA Technical Reports Server (NTRS)

Wessels, V.; Sahu, K. K.; Gangopadhyay, A. K.; Huett, V. T.; Canepari, S.; Goldman, A. I.; Hyers, R. W.; Kramer, M. J.; Rogers, J. R.; Kelton, K. F.;

Flexibility of centromere and kinetochore structures

PubMed Central

Burrack, Laura S.; Berman, Judith

2012-01-01

Centromeres, and the kinetochores that assemble on them, are essential for accurate chromosome segregation. Diverse centromere organization patterns and kinetochore structures have evolved in eukaryotes ranging from yeast to humans. In addition, centromere DNA and kinetochore position can vary even within individual cells. This flexibility manifests in several ways: centromere DNA sequences evolve rapidly, kinetochore positions shift in response to altered chromosome structure, and kinetochore complex numbers change in response to fluctuations in kinetochore protein levels. Despite their differences, all of these diverse structures promote efficient chromosome segregation. This robustness is inherent to chromosome segregation mechanisms and balances genome stability with adaptability. In this review, we explore the mechanisms and consequences of centromere and kinetochore flexibility as well as the benefits and limitations of different experimental model systems for studying them. PMID:22445183

Effect of Homogenizing Heat Treatment of Liquid Aluminum-Copper Alloys on the Structure of Rapidly Crystallized Specimens

NASA Astrophysics Data System (ADS)

Astaf'ev, V. V.; Kurochkin, A. R.; Yablonskikh, T. I.; Brodova, I. G.; Popel', P. S.

2017-11-01

Centrifugal casting into a massive slot chill mold was used to prepare two series of specimens of alloys of the Al - Cu system, containing from 10 to 32.2 at.% Cu. The first series was fabricated without a homogenizing heat treatment of the melt, while the second series was fabricated with heating of the melt to 1400°C. Both kinds of specimens were cast at the same temperature in order to provide for the same cooling rate of about 104 K/sec. The structures, phase compositions and microhardnesses of the structural components are compared. It is established that the homogenizing heat treatment changes the kinetics of crystallization and, hence, the proportion of phases in the alloy structure and the copper content in them.

Mechanism of Resilin Elasticity

PubMed Central

Qin, Guokui; Hu, Xiao; Cebe, Peggy; Kaplan, David L.

2012-01-01

Resilin is critical in the flight and jumping systems of insects as a polymeric rubber-like protein with outstanding elasticity. However, insight into the underlying molecular mechanisms responsible for resilin elasticity remains undefined. Here we report the structure and function of resilin from Drosophila CG15920. A reversible beta-turn transition was identified in the peptide encoded by exon III and for full length resilin during energy input and release, features that correlate to the rapid deformation of resilin during functions in vivo. Micellar structures and nano-porous patterns formed after beta-turn structures were present via changes in either the thermal or mechanical inputs. A model is proposed to explain the super elasticity and energy conversion mechanisms of resilin, providing important insight into structure-function relationships for this protein. Further, this model offers a view of elastomeric proteins in general where beta-turn related structures serve as fundamental units of the structure and elasticity. PMID:22893127

Neuroplasticity as a function of second language learning: anatomical changes in the human brain.

PubMed

Li, Ping; Legault, Jennifer; Litcofsky, Kaitlyn A

2014-09-01

The brain has an extraordinary ability to functionally and physically change or reconfigure its structure in response to environmental stimulus, cognitive demand, or behavioral experience. This property, known as neuroplasticity, has been examined extensively in many domains. But how does neuroplasticity occur in the brain as a function of an individual's experience with a second language? It is not until recently that we have gained some understanding of this question by examining the anatomical changes as well as functional neural patterns that are induced by the learning and use of multiple languages. In this article we review emerging evidence regarding how structural neuroplasticity occurs in the brain as a result of one's bilingual experience. Our review aims at identifying the processes and mechanisms that drive experience-dependent anatomical changes, and integrating structural imaging evidence with current knowledge of functional neural plasticity of language and other cognitive skills. The evidence reviewed so far portrays a picture that is highly consistent with structural neuroplasticity observed for other domains: second language experience-induced brain changes, including increased gray matter (GM) density and white matter (WM) integrity, can be found in children, young adults, and the elderly; can occur rapidly with short-term language learning or training; and are sensitive to age, age of acquisition, proficiency or performance level, language-specific characteristics, and individual differences. We conclude with a theoretical perspective on neuroplasticity in language and bilingualism, and point to future directions for research. Copyright © 2014 Elsevier Ltd. All rights reserved.

Resilience of Alaska's Boreal Forest to Climatic Change

NASA Technical Reports Server (NTRS)

Chapin, F. S., III; McGuire, A. D.; Ruess, R. W.; Hollingsworth, T. N.; Mack, M. C.; Johnstone, J. F.; Kasischke, E. S.; Euskirchen, E. S.; Jones, J. B.; Jorgenson, M. T.;

Resilience of Alaska’s boreal forest to climatic change

USGS Publications Warehouse

Chapin, F.S.; McGuire, A. David; Ruess, Roger W.; Hollingsworth, Teresa N.; Mack, M.C.; Johnstone, J.F.; Kasischke, E.S.; Euskirchen, E.S.; Jones, J.B.; Jorgenson, M.T.; Kielland, K.; Kofinas, G.; Turetsky, M.R.; Yarie, J.; Lloyd, A.H.; Taylor, D.L.

2010-01-01

This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These changes have modified key structural features, feedbacks, and interactions in the boreal forest, including reduced effects of upland permafrost on regional hydrology, expansion of boreal forest into tundra, and amplification of climate warming because of reduced albedo (shorter winter season) and carbon release from wildfires. Other temperature-sensitive processes for which no trends have been detected include composition of plant and microbial communities, long-term landscape-scale change in carbon stocks, stream discharge, mammalian population dynamics, and river access and subsistence opportunities for rural indigenous communities. Projections of continued warming suggest that Alaska’s boreal forest will undergo significant functional and structural changes within the next few decades that are unprecedented in the last 6000 years. The impact of these social–ecological changes will depend in part on the extent of landscape reorganization between uplands and lowlands and on policies regulating subsistence opportunities for rural communities.

How will coral reef fish communities respond to climate-driven disturbances? Insight from landscape-scale perturbations.

PubMed

Adam, Thomas C; Brooks, Andrew J; Holbrook, Sally J; Schmitt, Russell J; Washburn, Libe; Bernardi, Giacomo

2014-09-01

Global climate change is rapidly altering disturbance regimes in many ecosystems including coral reefs, yet the long-term impacts of these changes on ecosystem structure and function are difficult to predict. A major ecosystem service provided by coral reefs is the provisioning of physical habitat for other organisms, and consequently, many of the effects of climate change on coral reefs will be mediated by their impacts on habitat structure. Therefore, there is an urgent need to understand the independent and combined effects of coral mortality and loss of physical habitat on reef-associated biota. Here, we use a unique series of events affecting the coral reefs around the Pacific island of Moorea, French Polynesia to differentiate between the impacts of coral mortality and the degradation of physical habitat on the structure of reef fish communities. We found that, by removing large amounts of physical habitat, a tropical cyclone had larger impacts on reef fish communities than an outbreak of coral-eating sea stars that caused widespread coral mortality but left the physical structure intact. In addition, the impacts of declining structural complexity on reef fish assemblages accelerated as structure became increasingly rare. Structure provided by dead coral colonies can take up to decades to erode following coral mortality, and, consequently, our results suggest that predictions based on short-term studies are likely to grossly underestimate the long-term impacts of coral decline on reef fish communities.

Effect of initial microstructure on the compactability of rapidly solidified Ti-rich TiAl powder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishida, M.; Chiba, A.; Morizono, Y.

1997-12-31

Initial microstructure dependence of compactability at elevated temperature in rapidly solidified Ti-rich TiAl alloy powders produced by plasma rotating electrode process (PREP) has been investigated. There were two kinds of powders with respect to the microstructure. The first one had a surface relief of a martensitic phase, which was referred as M powder. The second one had a dendritic structure, which was referred as D powder. {alpha}{sub 2}+{gamma} microduplex and {alpha}{sub 2}/{gamma} lamellar structures were formed in M and D powders of the Ti-40 at%Al alloy by heat treatment at 1,273 K, respectively. The microduplex structure consisted of {gamma} precipitatemore » in the twin related {alpha}{sub 2} matrix with the usual orientation relationship. It was difficult to compact the D powder by hot pressing at 1,273 K under 50 MPa for 14.4 ks. On the other hand, the M powder was compacted easily by hot pressing with the same condition. The twin related {alpha}{sub 2} and {alpha}{sub 2} boundary changed to random ones and the {alpha}{sub 2} and {gamma} phases lost the usual orientation relationship in the duplex structure during the hot pressing. In other words, the low energy boundaries were changed to the high energy ones suitable for grain boundary sliding. Dislocations were scarcely observed inside of both the {alpha}{sub 2} and {gamma} crystal grains. It was concluded that the grain boundary sliding was a predominant deformation mode in the M powder during the hot pressing. D and M powders in Ti-45 and 47 at%Al alloys showed the same tendency as those in Ti-40 at%Al alloy during hot pressing.« less

Complement activation on B lymphocytes opsonized with rituximab or ofatumumab produces substantial changes in membrane structure preceding cell lysis.

PubMed

Beum, Paul V; Lindorfer, Margaret A; Beurskens, Frank; Stukenberg, P Todd; Lokhorst, Henk M; Pawluczkowycz, Andrew W; Parren, Paul W H I; van de Winkel, Jan G J; Taylor, Ronald P

2008-07-01

Binding of the CD20 mAb rituximab (RTX) to B lymphocytes in normal human serum (NHS) activates complement (C) and promotes C3b deposition on or in close proximity to cell-bound RTX. Based on spinning disk confocal microscopy analyses, we report the first real-time visualization of C3b deposition and C-mediated killing of RTX-opsonized B cells. C activation by RTX-opsonized Daudi B cells induces rapid membrane blebbing and generation of long, thin structures protruding from cell surfaces, which we call streamers. Ofatumumab, a unique mAb that targets a distinct binding site (the small loop epitope) of the CD20 Ag, induces more rapid killing and streaming on Daudi cells than RTX. In contrast to RTX, ofatumumab promotes streamer formation and killing of ARH77 cells and primary B cells from patients with chronic lymphocytic leukemia. Generation of streamers requires C activation; no streaming occurs in media, NHS-EDTA, or in sera depleted of C5 or C9. Streamers can be visualized in bright field by phase imaging, and fluorescence-staining patterns indicate they contain membrane lipids and polymerized actin. Streaming also occurs if cells are reacted in medium with bee venom melittin, which penetrates cells and forms membrane pores in a manner similar to the membrane-attack complex of C. Structures similar to streamers are demonstrable when Ab-opsonized sheep erythrocytes (non-nucleated cells) are reacted with NHS. Taken together, our findings indicate that the membrane-attack complex is a key mediator of streaming. Streamer formation may, thus, represent a membrane structural change that can occur shortly before complement-induced cell death.

A key agonist-induced conformational change in the cannabinoid receptor CB1 is blocked by the allosteric ligand Org 27569.

PubMed

Fay, Jonathan F; Farrens, David L

2012-09-28

Allosteric ligands that modulate how G protein-coupled receptors respond to traditional orthosteric drugs are an exciting and rapidly expanding field of pharmacology. An allosteric ligand for the cannabinoid receptor CB1, Org 27569, exhibits an intriguing effect; it increases agonist binding, yet blocks agonist-induced CB1 signaling. Here we explored the mechanism behind this behavior, using a site-directed fluorescence labeling approach. Our results show that Org 27569 blocks conformational changes in CB1 that accompany G protein binding and/or activation, and thus inhibit formation of a fully active CB1 structure. The underlying mechanism behind this behavior is that simultaneous binding of Org 27569 produces a unique agonist-bound conformation, one that may resemble an intermediate structure formed on the pathway to full receptor activation.

The Use of Gene Modification and Advanced Molecular Structure Analyses towards Improving Alfalfa Forage.

PubMed

Lei, Yaogeng; Hannoufa, Abdelali; Yu, Peiqiang

2017-01-29

Alfalfa is one of the most important legume forage crops in the world. In spite of its agronomic and nutritive advantages, alfalfa has some limitations in the usage of pasture forage and hay supplement. High rapid degradation of protein in alfalfa poses a risk of rumen bloat to ruminants which could cause huge economic losses for farmers. Coupled with the relatively high lignin content, which impedes the degradation of carbohydrate in rumen, alfalfa has unbalanced and asynchronous degradation ratio of nitrogen to carbohydrate (N/CHO) in rumen. Genetic engineering approaches have been used to manipulate the expression of genes involved in important metabolic pathways for the purpose of improving the nutritive value, forage yield, and the ability to resist abiotic stress. Such gene modification could bring molecular structural changes in alfalfa that are detectable by advanced structural analytical techniques. These structural analyses have been employed in assessing alfalfa forage characteristics, allowing for rapid, convenient and cost-effective analysis of alfalfa forage quality. In this article, we review two major obstacles facing alfalfa utilization, namely poor protein utilization and relatively high lignin content, and highlight genetic studies that were performed to overcome these drawbacks, as well as to introduce other improvements to alfalfa quality. We also review the use of advanced molecular structural analysis in the assessment of alfalfa forage for its potential usage in quality selection in alfalfa breeding.

The Use of Gene Modification and Advanced Molecular Structure Analyses towards Improving Alfalfa Forage

PubMed Central

Lei, Yaogeng; Hannoufa, Abdelali; Yu, Peiqiang

2017-01-01

Alfalfa is one of the most important legume forage crops in the world. In spite of its agronomic and nutritive advantages, alfalfa has some limitations in the usage of pasture forage and hay supplement. High rapid degradation of protein in alfalfa poses a risk of rumen bloat to ruminants which could cause huge economic losses for farmers. Coupled with the relatively high lignin content, which impedes the degradation of carbohydrate in rumen, alfalfa has unbalanced and asynchronous degradation ratio of nitrogen to carbohydrate (N/CHO) in rumen. Genetic engineering approaches have been used to manipulate the expression of genes involved in important metabolic pathways for the purpose of improving the nutritive value, forage yield, and the ability to resist abiotic stress. Such gene modification could bring molecular structural changes in alfalfa that are detectable by advanced structural analytical techniques. These structural analyses have been employed in assessing alfalfa forage characteristics, allowing for rapid, convenient and cost-effective analysis of alfalfa forage quality. In this article, we review two major obstacles facing alfalfa utilization, namely poor protein utilization and relatively high lignin content, and highlight genetic studies that were performed to overcome these drawbacks, as well as to introduce other improvements to alfalfa quality. We also review the use of advanced molecular structural analysis in the assessment of alfalfa forage for its potential usage in quality selection in alfalfa breeding. PMID:28146083

Positron annihilation lifetime spectroscopy (PALS) as a characterization technique for nanostructured self-assembled amphiphile systems.

PubMed

Dong, Aurelia W; Pascual-Izarra, Carlos; Pas, Steven J; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

2009-01-08

Positron annihilation lifetime spectroscopy (PALS) has potential as a novel rapid characterization method for self-assembly amphiphile systems; however, a lack of systematic correlation of PALS parameters with structural attributes has limited its more widespread application. In this study, using the well-characterized phytantriol/water and the phytantriol/vitamin E acetate/water self-assembly amphiphile systems, the impact of systematic structural changes controlled by changes in composition and temperature on PALS parameters has been studied. The PALS parameters (orthopositronium (oPs) lifetime and intensity signatures) were shown to be sensitive to the molecular packing and mobility of the self-assembled lipid molecules in various lyotropic liquid crystalline phases, enabling differentiation between liquid crystalline structures. The oPs lifetime, related to the molecular packing and mobility, is correlated with rheological properties of the individual mesophases. The oPs lifetime links the lipid chain packing and mobility in the various mesophases to resultant macroscopic properties, such as permeability, which is critical for the use of these mesophase structures as diffusion-controlled release matrices for active liposoluble compounds.

Ereptiospiration.

PubMed

Woolley, Christine; Garcia, Antonio A; Santello, Marco

2017-04-12

Pure coconut oil, lanolin, and acetaminophen were vaporized at rates of 1-50 mg/min, using a porous network exhibiting a temperature gradient from 5000 to 5500 K/mm, without incurring noticeable chemical changes due to combustion, oxidation, or other thermally-induced chemical structural changes. The newly coined term "ereptiospiration" is used here to describe this combination of thermal transpiration at high temperature gradients since the process can force the creation of thermal aerosols by rapid heating in a localized zone. Experimental data were generated for these materials using two different supports for metering the materials to the battery powered coil: namely, a stainless steel fiber bundle and a 3-D printed steel cartridge. Heating coconut oil, lanolin, or acetaminophen in a beaker to lower temperatures than those achieved at the surface of the coil showed noticeable and rapid degradation in the samples, while visual and olfactory observations for ereptiospiration showed no noticeable degradation in lanolin and coconut oil while HPLC chromatograms along with visual observation confirm that within the limit of detection, acetaminophen remains chemically unaltered by ereptiospiration.

Rapid Spectral Variability of the Symbiotic Star CH Cyg During One Night

NASA Astrophysics Data System (ADS)

Mikayilov, Kh. M.; Rustamov, B. N.; Alakbarov, I. A.; Rustamova, A. B.

2017-06-01

During one night (15.07.2015), within 6 hours 14 echelle spectrograms of this star were obtained. It was revealed that the profile of Ha and Hβ lines have two-component emission structure with a central absorption, parameters which vary from spectrum to spectrum during the night. The intensity of blue emission component (V) have been changed strongly during the night: the value of ratio of intensities of violet and red components (V/R) of line Hα decreased from 0:93 to 0:49 in the beginning and then increased to a value of 0.97. The synchronous variations of values of V/R for the Hα and Hβ lines have been revealed. The parameters of blue emission components of Hα and of line Hel λ5876 Å are correlated. We propose that revealed by us the rapid spectral changes in the spectrum of the star CH Cyg could be connected with a flickering in the optical brightness of the star that is typical for the active phase of this system.

Dynamically Tunable Cell Culture Platforms for Tissue Engineering and Mechanobiology

PubMed Central

Uto, Koichiro; Tsui, Jonathan H.; DeForest, Cole A.; Kim, Deok-Ho

2016-01-01

Human tissues are sophisticated ensembles of many distinct cell types embedded in the complex, but well-defined, structures of the extracellular matrix (ECM). Dynamic biochemical, physicochemical, and mechano-structural changes in the ECM define and regulate tissue-specific cell behaviors. To recapitulate this complex environment in vitro, dynamic polymer-based biomaterials have emerged as powerful tools to probe and direct active changes in cell function. The rapid evolution of polymerization chemistries, structural modulation, and processing technologies, as well as the incorporation of stimuli-responsiveness, now permit synthetic microenvironments to capture much of the dynamic complexity of native tissue. These platforms are comprised not only of natural polymers chemically and molecularly similar to ECM, but those fully synthetic in origin. Here, we review recent in vitro efforts to mimic the dynamic microenvironment comprising native tissue ECM from the viewpoint of material design. We also discuss how these dynamic polymer-based biomaterials are being used in fundamental cell mechanobiology studies, as well as towards efforts in tissue engineering and regenerative medicine. PMID:28522885

Cerium chloride stimulated controlled conversion of B-to-Z DNA in self-assembled nanostructures.

PubMed

Bhanjadeo, Madhabi M; Nayak, Ashok K; Subudhi, Umakanta

2017-01-22

DNA adopts different conformation not only because of novel base pairs but also while interacting with inorganic or organic compounds. Self-assembled branched DNA (bDNA) structures or DNA origami that change conformation in response to environmental cues hold great promises in sensing and actuation at the nanoscale. Recently, the B-Z transition in DNA is being explored to design various nanomechanical devices. In this communication we have demonstrated that Cerium chloride binds to the phosphate backbone of self-assembled bDNA structure and induce B-to-Z transition at physiological concentration. The mechanism of controlled conversion from right-handed to left-handed has been assayed by various dye binding studies using CD and fluorescence spectroscopy. Three different bDNA structures have been identified to display B-Z transition. This approach provides a rapid and reversible means to change bDNA conformation, which can be used for dynamic and progressive control at the nanoscale. Copyright © 2016 Elsevier Inc. All rights reserved.

Dynamic Re-wiring of Neural Circuits in the Motor Cortex in Mouse Models of Parkinson's Disease

PubMed Central

Lalchandani, Rupa R.; Cui, Yuting; Shu, Yu; Xu, Tonghui; Ding, Jun B.

2015-01-01

SUMMARY Dynamic adaptations in synaptic plasticity are critical for learning new motor skills and maintaining memory throughout life, which rapidly decline with Parkinson's disease (PD). Plasticity in the motor cortex is important for acquisition and maintenance of novel motor skills, but how the loss of dopamine in PD leads to disrupted structural and functional plasticity in the motor cortex is not well understood. Here, we utilized mouse models of PD and 2-photon imaging to show that dopamine depletion resulted in structural changes in the motor cortex. We further discovered that dopamine D1 and D2 receptor signaling were linked to selectively and distinctly regulating these aberrant changes in structural and functional plasticity. Our findings suggest that both D1 and D2 receptor signaling regulate motor cortex plasticity, and loss of dopamine results in atypical synaptic adaptations that may contribute to the impairment of motor performance and motor memory observed in PD. PMID:26237365

The Career and Work Adaptability Questionnaire (CWAQ): a first contribution to its validation.

PubMed

Nota, Laura; Ginevra, Maria Cristina; Soresi, Salvatore

2012-12-01

Over the last decade, occupational changes have the rapidly changing job market has begun to demand that people more actively construct their professional lives and acquire career adaptability. The aim of the present study was to develop a specific, new instrument, "Career and Work Adaptability", to assess degree of adaptability in adolescents planning their futures. We conducted three studies, the first of which aimed to formulate the instrument's items and to verify its factor structure; the second study confirmed the instrument's multidimensional structure and evaluated its discriminant validity; the third study was conducted to verify the factorial structure's across-gender invariance and to evaluate its stability over time. Our results showed that the instrument is an effective and multidimensional instrument for accurately measuring career adaptability. Specifically, it can serve as a useful vocational guidance tool in analyzing adolescents' career adaptability. Copyright © 2012 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Brain Hyperglycemia Induced by Heroin: Association with Metabolic Neural Activation.

PubMed

Solis, Ernesto; Bola, R Aaron; Fasulo, Bradley J; Kiyatkin, Eugene A

2017-02-15

Glucose enters the brain extracellular space from arterial blood, and its proper delivery is essential for metabolic activity of brain cells. By using enzyme-based biosensors coupled with high-speed amperometry in freely moving rats, we previously showed that glucose levels in the nucleus accumbens (NAc) display high variability, increasing rapidly following exposure to various arousing stimuli. In this study, the same technology was used to assess NAc glucose fluctuations induced by intravenous heroin. Heroin passively injected at a low dose optimal for maintaining self-administration behavior (100 μg/kg) induces a rapid but moderate glucose rise (∼150-200 μM or ∼15-25% over resting baseline). When the heroin dose was doubled and tripled, the increase became progressively larger in magnitude and longer in duration. Heroin-induced glucose increases also occurred in other brain structures (medial thalamus, lateral striatum, hippocampus), suggesting that brain hyperglycemia is a whole-brain phenomenon but changes were notably distinct in each structure. While local vasodilation appears to be the possible mechanism underlying the rapid rise in extracellular glucose levels, the driving factor for this vasodilation (central vs peripheral) remains to be clarified. The heroin-induced NAc glucose increases positively correlated with increases in intracerebral heat production determined in separate experiments using multisite temperature recordings (NAc, temporal muscle and skin). However, glucose levels rise very rapidly, preceding much slower increases in brain heat production, a measure of metabolic activation associated with glucose consumption.

Rapid activation by 3,5,3'-L-triiodothyronine of adenosine 5'-monophosphate-activated protein kinase/acetyl-coenzyme a carboxylase and akt/protein kinase B signaling pathways: relation to changes in fuel metabolism and myosin heavy-chain protein content in rat gastrocnemius muscle in vivo.

PubMed

de Lange, Pieter; Senese, Rosalba; Cioffi, Federica; Moreno, Maria; Lombardi, Assunta; Silvestri, Elena; Goglia, Fernando; Lanni, Antonia

2008-12-01

T3 stimulates metabolic rate in many tissues and induces changes in fuel use. The pathways by which T3 induces metabolic/structural changes related to altered fuel use in skeletal muscle have not been fully clarified. Gastrocnemius muscle (isolated at different time points after a single injection of T3 into hypothyroid rats), displayed rapid inductions of AMP-activated protein kinase (AMPK) phosphorylation (threonine 172; within 6 h) and acetyl-coenzyme A carboxylase phosphorylation (serine 79; within 12 h). As a consequence, increases occurred in mitochondrial fatty acid oxidation and carnitine palmitoyl transferase activity. Concomitantly, T3 stimulated signaling toward increased glycolysis through a rapid increase in Akt/protein kinase B (serine 473) phosphorylation (within 6 h) and a directly related increase in the activity of phosphofructokinase. The kinase specificity of the above effects was verified by treatment with inhibitors of AMPK and Akt activity (compound C and wortmannin, respectively). In contrast, glucose transporter 4 translocation to the membrane (activated by T3 within 6 h) was maintained when either AMPK or Akt activity was inhibited. The metabolic changes were accompanied by a decline in myosin heavy-chain Ib protein [causing a shift toward the fast-twitch (glycolytic) phenotype]. The increases in AMPK and acetyl-coenzyme A carboxylase phosphorylation were transient events, both levels declining from 12 h after the T3 injection, but Akt phosphorylation remained elevated until at least 48h after the injection. These data show that in skeletal muscle, T3 stimulates both fatty acid and glucose metabolism through rapid activations of the associated signaling pathways involving AMPK and Akt/protein kinase B.

Rapid prototyping of three-dimensional microstructures from multiwalled carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hung, W.H.; Kumar, Rajay; Bushmaker, Adam

The authors report a method for creating three-dimensional carbon nanotube structures, whereby a focused laser beam is used to selectively burn local regions of a dense forest of multiwalled carbon nanotubes. Raman spectroscopy and scanning electron microscopy are used to quantify the threshold for laser burnout and depth of burnout. The minimum power density for burning carbon nanotubes in air is found to be 244 {mu}W/{mu}m{sup 2}. We create various three-dimensional patterns using this method, illustrating its potential use for the rapid prototyping of carbon nanotube microstructures. Undercut profiles, changes in nanotube density, and nanoparticle formation are observed after lasermore » surface treatment and provide insight into the dynamic process of the burnout mechanism.« less

Animal behaviour shapes the ecological effects of ocean acidification and warming: moving from individual to community-level responses.

PubMed

Nagelkerken, Ivan; Munday, Philip L

2016-03-01

Biological communities are shaped by complex interactions between organisms and their environment as well as interactions with other species. Humans are rapidly changing the marine environment through increasing greenhouse gas emissions, resulting in ocean warming and acidification. The first response by animals to environmental change is predominantly through modification of their behaviour, which in turn affects species interactions and ecological processes. Yet, many climate change studies ignore animal behaviour. Furthermore, our current knowledge of how global change alters animal behaviour is mostly restricted to single species, life phases and stressors, leading to an incomplete view of how coinciding climate stressors can affect the ecological interactions that structure biological communities. Here, we first review studies on the effects of warming and acidification on the behaviour of marine animals. We demonstrate how pervasive the effects of global change are on a wide range of critical behaviours that determine the persistence of species and their success in ecological communities. We then evaluate several approaches to studying the ecological effects of warming and acidification, and identify knowledge gaps that need to be filled, to better understand how global change will affect marine populations and communities through altered animal behaviours. Our review provides a synthesis of the far-reaching consequences that behavioural changes could have for marine ecosystems in a rapidly changing environment. Without considering the pervasive effects of climate change on animal behaviour we will limit our ability to forecast the impacts of ocean change and provide insights that can aid management strategies. © 2015 John Wiley & Sons Ltd.

Change of the image of the city in process of using traffic infrastructure

NASA Astrophysics Data System (ADS)

Alihodžić, Rifat; Vasiljević Tomić, Dragana; Iablonskii, Leonid

2017-10-01

Unique urban image cannot be experienced without moving within its structure. This paper deals with phenomenology considering changes of images of the city and influential factors closely related to it. Infrastructure gives basic structural scheme of every city, so its planning requires a high level proficiency. Some changes in these images can be observed during longer period of time. Sometimes it includes rapid changes of temporal layers, generated by building new urban elements on the exact same place where the old ones existed; while lighter change during the time passing is a regular occurrence. Creating completely new urban frames, caused by expanding the city, represents its dynamical variant. Topography is a significant factor, giving distinctive feature to the urbanity. This paper considers factors identified as generators of the change of the urban image, based on research so far. The structural elements are considered with the utmost attention. The importance of the city landmark, monumental complexes not possessing these features but having the importance in image of the city stability (as well as the inhabitants’ memory) are crucial elements of identifying its picture. Another significant factor is related to individual personal experience. However, there are also certain factors of significance features, but not considered within this paper. One such factor is change in coloring, being the special topic itself. The purpose of this work is to indicate that urban planning requires special attention in order to keep continuous nature of the urban image for the city to preserve its visual identity.

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

PubMed Central

Takmakov, Pavel; Ruda, Kiersten; Phillips, K Scott; Isayeva, Irada S; Krauthamer, Victor; Welle, Cristin G

2017-01-01

Objective A challenge for implementing high bandwidth cortical brain–machine interface devices in patients is the limited functional lifespan of implanted recording electrodes. Development of implant technology currently requires extensive non-clinical testing to demonstrate device performance. However, testing the durability of the implants in vivo is time-consuming and expensive. Validated in vitro methodologies may reduce the need for extensive testing in animal models. Approach Here we describe an in vitro platform for rapid evaluation of implant stability. We designed a reactive accelerated aging (RAA) protocol that employs elevated temperature and reactive oxygen species (ROS) to create a harsh aging environment. Commercially available microelectrode arrays (MEAs) were placed in a solution of hydrogen peroxide at 87 °C for a period of 7 days. We monitored changes to the implants with scanning electron microscopy and broad spectrum electrochemical impedance spectroscopy (1 Hz–1 MHz) and correlated the physical changes with impedance data to identify markers associated with implant failure. Main results RAA produced a diverse range of effects on the structural integrity and electrochemical properties of electrodes. Temperature and ROS appeared to have different effects on structural elements, with increased temperature causing insulation loss from the electrode microwires, and ROS concentration correlating with tungsten metal dissolution. All array types experienced impedance declines, consistent with published literature showing chronic (>30 days) declines in array impedance in vivo. Impedance change was greatest at frequencies <10 Hz, and smallest at frequencies 1 kHz and above. Though electrode performance is traditionally characterized by impedance at 1 kHz, our results indicate that an impedance change at 1 kHz is not a reliable predictive marker of implant degradation or failure. Significance ROS, which are known to be present in vivo, can create structural damage and change electrical properties of MEAs. Broad-spectrum electrical impedance spectroscopy demonstrates increased sensitivity to electrode damage compared with single-frequency measurements. RAA can be a useful tool to simulate worst-case in vivo damage resulting from chronic electrode implantation, simplifying the device development lifecycle. PMID:25627426

The dead do not lie: using skeletal remains for rapid assessment of historical small-mammal community baselines

PubMed Central

Terry, Rebecca C.

2010-01-01

Conservation and restoration efforts are often hindered by a lack of historical baselines that pre-date intense anthropogenic environmental change. In this paper I document that natural accumulations of skeletal remains represent a potential source of high-quality data on the historical composition and structure of small-mammal communities. I do so by assessing the fidelity of modern, decadal and centennial-scale time-averaged samples of skeletal remains (concentrated by raptor predation) to the living small-mammal communities from which they are derived. To test the power of skeletal remains to reveal baseline shifts, I employ the design of a natural experiment, comparing two taphonomically similar Great Basin cave localities in areas where anthropogenic land-use practices have diverged within the last century. I find relative stasis at the undisturbed site, but document rapid restructuring of the small-mammal community at the site subjected to recent disturbance. I independently validate this result using historical trapping records to show that dead remains accurately capture both the magnitude and direction of this baseline shift. Surveys of skeletal remains therefore provide a simple, powerful and rapid alternative approach for gaining insight into the historical structure and dynamics of modern small-mammal communities. PMID:20031992

Defect reduction in MBE-grown AlN by multicycle rapid thermal annealing

NASA Astrophysics Data System (ADS)

Greenlee, Jordan D.; Gunning, Brendan; Feigelson, Boris N.; Anderson, Travis J.; Koehler, Andrew D.; Hobart, Karl D.; Kub, Francis J.; Doolittle, W. Alan

2016-01-01

Multicycle rapid thermal annealing (MRTA) is shown to reduce the defect density of molecular beam epitaxially grown AlN films. No damage to the AlN surface occurred after performing the MRTA process at 1520°C. However, the individual grain structure was altered, with the emergence of step edges. This change in grain structure and diffusion of AlN resulted in an improvement in the crystalline structure. The Raman E2 linewidth decreased, confirming an improvement in crystal quality. The optical band edge of the AlN maintained the expected value of 6.2 eV throughout MRTA annealing, and the band edge sharpened after MRTA annealing at increased temperatures, providing further evidence of crystalline improvement. X-ray diffraction shows a substantial improvement in the (002) and (102) rocking curve FWHM for both the 1400 and 1520°C MRTA annealing conditions compared to the as-grown films, indicating that the screw and edge type dislocation densities decreased. Overall, the MRTA post-growth annealing of AlN lowers defect density, and thus will be a key step to improving optoelectronic and power electronic devices. [Figure not available: see fulltext.

PREFACE: Trends in Aerospace Manufacturing 2009 International Conference

NASA Astrophysics Data System (ADS)

Ridgway, Keith; Gault, Rosemary; Allen, Adrian

2011-12-01

The aerospace industry is rapidly changing. New aircraft structures are being developed and aero-engines are becoming lighter and more environmentally friendly. In both areas, innovative materials and manufacturing methods are used in an attempt to get maximum performance for minimum cost. At the same time, the structure of the industry has changed and there has been a move from large companies designing, manufacturing components and assembling aircraft to one of large global supply chains headed by large system integrators. All these changes have forced engineers and managers to bring in innovations in design, materials, manufacturing technologies and supply chain management. In September 2009, the Advanced Manufacturing Research Centre (AMRC) at the University of Sheffield held the inaugural Trends in Aerospace Manufacturing conference (TRAM09). This brought together 28 speakers over two days, who presented in sessions on advanced manufacturing trends for the aerospace sector. Areas covered included new materials, including composites, advanced machining, state of the art additive manufacturing techniques, assembly and supply chain issues.

Usability: a critical success factor for managing change in the clinical info-structure.

PubMed

Kay, S

2005-06-01

There can be no doubt that the clinical info-structure is being significantly enriched with the deployment of new systems throughout the health sector. From a technological perspective, the initial emphasis has been mainly on functionality and only latterly on the usability of these clinical information systems. However, the large scale and rapid pace of the changes being wrought in the health sector will have a major impact on clinicians and patients, not least in how they interact with the technology. Therefore, it is not only hardware and software but people-ware, too, that needs to be actively managed; not simply a one-off functional specification but an ongoing, complex relationship. Usability is the human factor that encompasses the ethical, educational, and evaluative aspects of design. There is also a strong case for regarding usability of clinical information systems as a key critical success factor for the management of change within the health-care domain. In particular, the relationship between usability, and education and training is examined.

Photo-responsive surface topology in chiral nematic media

NASA Astrophysics Data System (ADS)

Liu, Danqing; Bastiaansen, Cees W. M.; Toonder, Jaap. M. J.; Broer, Dirk J.

2012-03-01

We report on the design and fabrication of 'smart surfaces' that exhibit dynamic changes in their surface topology in response to exposure to light. The principle is based on anisotropic geometric changes of a liquid crystal network upon a change of the molecular order parameter. The photomechanical property of the coating is induced by incorporating an azobenzene moiety into the liquid crystal network. The responsive surface topology consists of regions with two different types of molecular order: planar chiral-nematic areas and homeotropic. Under flood exposure with 365 nm light the surfaces deform from flat to one with a surface relief. The height of the relief structures is of the order of 1 um corresponding to strain difference of around 20%. Furthermore, we demonstrate surface reliefs can form either convex or concave structures upon exposure to UV light corresponding to the decrease or increase molecular order parameter, respectively, related to the isomeric state of the azobenzene crosslinker. The reversible deformation to the initial flat state occurs rapidly after removing the light source.

Family instability and early initiation of sexual activity in Western Kenya.

PubMed

Goldberg, Rachel E

2013-04-01

Epidemiological, economic, and social forces have produced high levels of volatility in family and household structure for young people growing up in sub-Saharan Africa in recent decades. However, scholarship on the family to date has not examined the influence of this family instability on young people's well-being. The current study employs unique life history calendar data from Western Kenya to investigate the relationship between instability in caregiving and early initiation of sexual activity. It draws on a body of work on parental union instability in the United States, and examines new dimensions of family change. Analyses reveal a positive association between transitions in primary caregiver and the likelihood of early sexual debut that is rapidly manifested following caregiver change and persists for a short period. The association is strongest at early ages, and there is a cumulative effect of multiple caregiver changes. The results highlight the importance of studying family stability in sub-Saharan Africa, as distinct from family structure, and for attention to dimensions such as age and recency.

Preparing the High School Classroom for Migrant English Language Learners (Preparación del aula de secundaria para estudiantes migrantes que aprenden inglés)

ERIC Educational Resources Information Center

Rouse, Megan Elizabeth

2014-01-01

In United States schools, the rate of immigrant English language learners is rapidly rising, affecting the lives of both students and teachers. This article will discuss the best ways to facilitate the students' language learning in a school setting; the type of structure, goals, and standards that can be expected; as well as ways to change the…

Linguistics, cognitive psychology, and the Now-or-Never bottleneck.

PubMed

Endress, Ansgar D; Katzir, Roni

2016-01-01

Christiansen & Chater (C&C)'s key premise is that "if linguistic information is not processed rapidly, that information is lost for good" (sect. 1, para. 1). From this "Now-or-Never bottleneck" (NNB), C&C derive "wide-reaching and fundamental implications for language processing, acquisition and change as well as for the structure of language itself" (sect. 2, para. 10). We question both the premise and the consequentiality of its purported implications.

Efficient Ultraviolet Light Detector Based on a Crystalline Viologen-Based Metal-Organic Framework with Rapid Visible Color Change under Irradiation.

PubMed

Hu, Shuzhi; Zhang, Jie; Chen, Shuhuang; Dai, Jingcao; Fu, Zhiyong

2017-11-22

A convenient colorimetric molecular system constructed by the zinc viologen-carboxylate framework is developed for naked eye detection of instantaneous UV exposure levels. Only narrow-band absorption in UV regions and a unique interpenetrated structure of its colorless crystal enable the system to give a fast response toward UV irradiance with intensity as low as 0.001 mw/cm 2 .

Preface -2017EMRS-Fall-symposium W: Stress, structure and stoichiometry effects on the properties of nanomaterials IV

NASA Astrophysics Data System (ADS)

Sánchez, Florencio; Craciun, Valentin

2018-07-01

Research on nanomaterials and nanostructures is continuing to grow at a rapid pace as they are used in many important devices like transistors, sensors, MEMS or components of modern tools for diagnosis and treatment in medicine. The functional properties of the materials used in these devices depend on their microstructure, and can be finely tuned using physical and chemical synthesis or various processing techniques that change the structure, composition, morphology and defects type and concentration. The investigation of stress, stoichiometry, phase structure and defects at atomic level is necessary to understand, model and further optimize the electric, magnetic, optical and mechanical properties of the nanosystems and for engineers to design new, better and more reliable devices.

Relative activities on and uptake by human blood platelets of 5-hydroxytryptamine and several analogues

PubMed Central

Born, G. V. R.; Juengjaroen, Kanchana; Michal, F.

1972-01-01

1. The specificity of platelet receptor sites for 5-HT uptake and for the rapid morphological change and aggregation was investigated with 5-hydroxy-tryptamine (5-HT) and seventeen analogues as well as with some antagonists of 5-HT. 2. The analogues, with the exception of 5-hydroxy-N'N'-dibutyltryptamine, caused the rapid morphological change in platelets. In concentrations below those needed to produce the agonistic action (viz. 0.05-2.0 μM), these analogues themselves inhibited competitively the shape change caused by 5-HT. 3. The velocity of change in shape caused by 5-HT was reduced in low Na media. 4. Ten analogues produced platelet aggregation; three of these, viz. 5-methoxy-α-methyltryptamine, 5-hydroxy-α-methyltryptamine and 5-hydroxy-N'N'-diisopropyltryptamine), were approximately equipotent with 5-HT. Six analogues did not induce platelet aggregation. 5. All the analogues which prevented the initial change in shape of platelets caused by 5-HT also inhibited its aggregating effect, apparently competitively with low Ki values (0.02-1.6 μM). 6. As with the inhibition of shape change, the inhibition of aggregation shows relatively low structural specificity of the receptor site. 7. Methysergide was a potent inhibitor of shape change and aggregation (Ki∼0.03 μM); imipramine was much less inhibitory (Ki∼5-10 μM). 8. Only one analogue (5-hydroxy-α-methyltryptamine) was taken up like 5-HT by platelets. All the other analogues inhibited the uptake of 5-HT by platelets (Ki=0.2-2.7 μM). 9. Methysergide was a weak inhibitor of 5-HT uptake (Ki∼125 μM) whereas imipramine was very effective (Ki∼0.3 μM). 10. Our results show that the initial change in shape of platelets is required for and precedes aggregation. The structural specificity of the platelet receptor concerned with shape change and aggregation caused by 5-HT appears low whereas the uptake mechanism is a highly specific one. The uptake probably proceeds through more than one step, the relationship between the steps is not yet clear. PMID:5015032

Observing Changing Ecological Diversity in the Anthropocene

NASA Technical Reports Server (NTRS)

Schimel, David S.; Asner, Gregory P.; Moorcroft, Paul

2012-01-01

As the world enters the Anthropocene, the planet's environment is changing rapidly, putting critical ecosystem services at risk. Understanding and forecasting how ecosystems will change over the coming decades requires understanding the sensitivity of species to environmental change. The extant distribution of species and functional groups contains valuable information about the performance of different species in different environments. However, with high rates of environmental change, information inherent in ranges of many species will disappear, since that information exists only under quasi-equilibrium conditions. The information content of distributional data obtained now is greater than data obtained in the future. New remote sensing technologies can map chemical and structural traits of plant canopies and allow inference of trait and in many cases, species ranges. Current satellite remote sensing data can only produce relatively simple classifications, but new techniques have dramatically higher biological information content.

Methods and measurement variance for field estimations of coral colony planar area using underwater photographs and semi-automated image segmentation.

PubMed

Neal, Benjamin P; Lin, Tsung-Han; Winter, Rivah N; Treibitz, Tali; Beijbom, Oscar; Kriegman, David; Kline, David I; Greg Mitchell, B

2015-08-01

Size and growth rates for individual colonies are some of the most essential descriptive parameters for understanding coral communities, which are currently experiencing worldwide declines in health and extent. Accurately measuring coral colony size and changes over multiple years can reveal demographic, growth, or mortality patterns often not apparent from short-term observations and can expose environmental stress responses that may take years to manifest. Describing community size structure can reveal population dynamics patterns, such as periods of failed recruitment or patterns of colony fission, which have implications for the future sustainability of these ecosystems. However, rapidly and non-invasively measuring coral colony sizes in situ remains a difficult task, as three-dimensional underwater digital reconstruction methods are currently not practical for large numbers of colonies. Two-dimensional (2D) planar area measurements from projection of underwater photographs are a practical size proxy, although this method presents operational difficulties in obtaining well-controlled photographs in the highly rugose environment of the coral reef, and requires extensive time for image processing. Here, we present and test the measurement variance for a method of making rapid planar area estimates of small to medium-sized coral colonies using a lightweight monopod image-framing system and a custom semi-automated image segmentation analysis program. This method demonstrated a coefficient of variation of 2.26% for repeated measurements in realistic ocean conditions, a level of error appropriate for rapid, inexpensive field studies of coral size structure, inferring change in colony size over time, or measuring bleaching or disease extent of large numbers of individual colonies.

White Matter Development in Adolescence: The Influence of Puberty and Implications for Affective Disorders

PubMed Central

Ladouceur, Cecile D.; Peper, Jiska S.; Crone, Eveline A.; Dahl, Ronald E.

2011-01-01

There have been rapid advances in understanding a broad range of changes in brain structure and function during adolescence, and a growing interest in identifying which of these neurodevelopmental changes are directly linked with pubertal maturation—at least in part because of their potential to provide insights into the numerous emotional and behavioral health problems that emerge during this developmental period. This review focuses on what is known about the influence of puberty on white matter development in adolescence. We focus on white matter because of its role in providing the structural architectural organization of the brain and as a structural correlate of communication within complex neural systems. We begin with a review of studies that report sex differences or sex by age interactions in white matter development as these findings can provide, although indirectly, information relevant to puberty-related changes. Studies are also critically reviewed based on methodological procedures used to assess pubertal maturation and relations with white matter changes. Findings are discussed in light of their implications for the development of neural systems underlying the regulation of emotion and behavior and how alterations in the development of these systems may mediate risk for affective disorders in vulnerable adolescents. PMID:22247751

Changes in ecosystem services associated with planting structures of cropland: A case study in Minle County in China

NASA Astrophysics Data System (ADS)

Liu, Yaqun; Song, Wei; Mu, Fengyun

2017-12-01

The cropland ecosystem provides essential direct and indirect products and services to mankind such as food, fiber, biodiversity and soil conservation. A change of crop planting structure can change the ecosystem services of cropland by affecting land use type. In recent years, under the influence of regional comparative advantage and consumer demand changes, the crop planting structure in China has changed rapidly. However, there is still a lack of deep understanding on the effect of such a change in planting structure on the ecosystem services of cropland. Therefore, this research selected Minle County in the Heihe River Basin, which has small scattered croplands and a complex planting structure, as a study area. Based on the key time phase and optimal threshold of the normalized difference vegetation index (NDVI) data of the Thematic Mapper and Enhanced Thematic Mapper Plus (TM/ETM+) images, this study used the decision tree algorithm to classify and extract the crop planting structure in Minle County in 2007 and 2012 and to analyze the changes in its temporal and spatial patterns. Then, the market value method was adopted to estimate the effect of the change in crop planting structure on the ecosystem services of the cropland. From 2007 to 2012, the planting area of corn and rapeseed in Minle County increased by 5.86 × 103 ha and 5.10 × 103 ha, respectively. Conversely, the planting area of wheat and barley was reduced by 3.26 × 103 ha and 6.34 × 103 ha, respectively. These changes directly caused the increase of the ecosystem services value of corn and rapeseed by 1062.82 × 104 USD and 842.54 × 104 USD, respectively. The resulting reduction in the ecosystem services value of wheat and barley was 488.24 × 104 USD and 828.29 × 104 USD, respectively. Besides, the total ecosystem services value of cropland increased by 1564.98 × 104 USD. Further analysis found that the change in the crop planting structure caused an increase in the ecosystem services value of cropland of 359.44 × 104 USD, with a contribution rate of 22.97% to the total increase. The expansion of corn caused the increase of the ecosystem services value of cropland by 151.65 × 104 USD, with a contribution rate of 9.69% to the total increase. The change in crop planting structure in Minle County increased not only the economic benefits of crop planting, but also the ecosystem services of cropland.

Fine-scale genetic structure arises during range expansion of an invasive gecko.

PubMed

Short, Kristen Harfmann; Petren, Kenneth

2011-01-01

Processes of range expansion are increasingly important in light of current concerns about invasive species and range shifts due to climate change. Theoretical studies suggest that genetic structuring may occur during range expansion. Ephemeral genetic structure can have important evolutionary implications, such as propagating genetic changes along the wave front of expansion, yet few studies have shown evidence of such structure. We tested the hypothesis that genetic structure arises during range expansion in Hemidactylus mabouia, a nocturnal African gecko recently introduced to Florida, USA. Twelve highly variable microsatellite loci were used to screen 418 individuals collected from 43 locations from four sampling sites across Florida, representing a gradient from earlier (∼1990s) to very recent colonization. We found earlier colonized locations had little detectable genetic structure and higher allelic richness than more recently colonized locations. Genetic structuring was pronounced among locations at spatial scales of tens to hundreds of meters near the leading edge of range expansion. Despite the rapid pace of range expansion in this introduced gecko, dispersal is limited among many suitable habitat patches. Fine-scale genetic structure is likely the result of founder effects during colonization of suitable habitat patches. It may be obscured over time and by scale-dependent modes of dispersal. Further studies are needed to determine if such genetic structure affects adaptation and trait evolution in range expansions and range shifts.

Temporal Sequence of Cell Wall Disassembly in Rapidly Ripening Melon Fruit1

PubMed Central

Rose, Jocelyn K.C.; Hadfield, Kristen A.; Labavitch, John M.; Bennett, Alan B.

1998-01-01

The Charentais variety of melon (Cucumis melo cv Reticulatus F1 Alpha) was observed to undergo very rapid ripening, with the transition from the preripe to overripe stage occurring within 24 to 48 h. During this time, the flesh first softened and then exhibited substantial disintegration, suggesting that Charentais may represent a useful model system to examine the temporal sequence of changes in cell wall composition that typically take place in softening fruit. The total amount of pectin in the cell wall showed little reduction during ripening but its solubility changed substantially. Initial changes in pectin solubility coincided with a loss of galactose from tightly bound pectins, but preceded the expression of polygalacturonase (PG) mRNAs, suggesting early, PG-independent modification of pectin structure. Depolymerization of polyuronides occurred predominantly in the later ripening stages, and after the appearance of PG mRNAs, suggesting the existence of PG-dependent pectin degradation in later stages. Depolymerization of hemicelluloses was observed throughout ripening, and degradation of a tightly bound xyloglucan fraction was detected at the early onset of softening. Thus, metabolism of xyloglucan that may be closely associated with cellulose microfibrils may contribute to the initial stages of fruit softening. A model is presented of the temporal sequence of cell wall changes during cell wall disassembly in ripening Charentais melon. PMID:9625688

The Changing Relationship Between Family Size and Educational Attainment Over the Course of Socioeconomic Development: Evidence From Indonesia

PubMed Central

MARALANI, VIDA

2008-01-01

Many studies from developed countries show a negative correlation between family size and children’s schooling, while results from developing countries show this association ranging from positive to neutral to negative, depending on the context. The body of evidence suggests that this relationship changes as a society develops, but this theory has been difficult to assess because the existing evidence requires comparisons across countries with different social structures and at different levels of development. The world’s fourth most populous nation in 2007, Indonesia has developed rapidly in recent decades. This context provides the opportunity to study these relationships within the same rapidly developing setting to see if and how these associations change. Results show that in urban areas, the association between family size and children’s schooling was positive for older cohorts but negative for more recent cohorts. Models using instrumental variables to address the potential endogeneity of fertility confirm these results. In contrast, rural areas show no significant association between family size and children’s schooling for any cohort. These findings show how the relationship between family size and children’s schooling can differ within the same country and change over time as contextual factors evolve with socioeconomic development. PMID:18939668

Changing organisms in rapidly changing anthropogenic landscapes: the significance of the ‘Umwelt’-concept and functional habitat for animal conservation

PubMed Central

Van Dyck, Hans

2012-01-01

There is a growing recognition for the significance of evolutionary thinking in ecology and conservation biology. However, ecology and conservation studies often work with species-specific, fixed traits that ignore intraspecific variation. The way the habitat of a species is considered is an example of typological thinking biased by human perception. Structural habitat units (e.g., land cover types) as perceived by humans may not represent functional habitat units for other organisms. Human activity may also interfere with the environmental information used by organisms. Therefore, the Umwelt-concept from ethology needs to be integrated in the way we think about habitat and habitat selection. It states that different organisms live in different perceptual worlds dealing with specific subsamples of the environment as a result of their evolutionary and developmental history. The resource-based habitat concept is a functional habitat model based on resource distributions (consumables and conditions) and individual movements. This behavioural approach takes into account aspects that relate to the perceptual world of organisms. This approach may offer new opportunities for conservation and may help avoid failures with habitat restoration. Perceptual ability may be subject to adaptive change, but it may also constrain organisms from showing adaptive behaviours in rapidly changing environments. PMID:25568037

Changing organisms in rapidly changing anthropogenic landscapes: the significance of the 'Umwelt'-concept and functional habitat for animal conservation.

PubMed

Van Dyck, Hans

2012-02-01

There is a growing recognition for the significance of evolutionary thinking in ecology and conservation biology. However, ecology and conservation studies often work with species-specific, fixed traits that ignore intraspecific variation. The way the habitat of a species is considered is an example of typological thinking biased by human perception. Structural habitat units (e.g., land cover types) as perceived by humans may not represent functional habitat units for other organisms. Human activity may also interfere with the environmental information used by organisms. Therefore, the Umwelt-concept from ethology needs to be integrated in the way we think about habitat and habitat selection. It states that different organisms live in different perceptual worlds dealing with specific subsamples of the environment as a result of their evolutionary and developmental history. The resource-based habitat concept is a functional habitat model based on resource distributions (consumables and conditions) and individual movements. This behavioural approach takes into account aspects that relate to the perceptual world of organisms. This approach may offer new opportunities for conservation and may help avoid failures with habitat restoration. Perceptual ability may be subject to adaptive change, but it may also constrain organisms from showing adaptive behaviours in rapidly changing environments.

Phase field modeling of rapid crystallization in the phase-change material AIST

NASA Astrophysics Data System (ADS)

Tabatabaei, Fatemeh; Boussinot, Guillaume; Spatschek, Robert; Brener, Efim A.; Apel, Markus

2017-07-01

We carry out phase field modeling as a continuum simulation technique in order to study rapid crystallization processes in the phase-change material AIST (Ag4In3Sb67Te26). In particular, we simulate the spatio-temporal evolution of the crystallization of a molten area of the phase-change material embedded in a layer stack. The simulation model is adapted to the experimental conditions used for recent measurements of crystallization rates by a laser pulse technique. Simulations are performed for substrate temperatures close to the melting temperature of AIST down to low temperatures when an amorphous state is involved. The design of the phase field model using the thin interface limit allows us to retrieve the two limiting regimes of interface controlled (low temperatures) and thermal transport controlled (high temperatures) dynamics. Our simulations show that, generically, the crystallization velocity presents a maximum in the intermediate regime where both the interface mobility and the thermal transport, through the molten area as well as through the layer stack, are important. Simulations reveal the complex interplay of all different contributions. This suggests that the maximum switching velocity depends not only on material properties but also on the precise design of the thin film structure into which the phase-change material is embedded.

Rapid Penumbra and Lorentz Force Changes in an X1.0 Solar Flare

NASA Astrophysics Data System (ADS)

Xu, Zhe; Jiang, Yunchun; Yang, Jiayang; Yang, Bo; Bi, Yi

2016-03-01

We present observations of the violent changes in photospheric magnetic structures associated with an X1.1 flare, which occurred in a compact δ-configuration region in the following part of AR 11890 on 2013 November 8. In both central and peripheral penumbra regions of the small δ sunspot, these changes took place abruptly and permanently in the reverse direction during the flare: the inner/outer penumbra darkened/disappeared, where the magnetic fields became more horizontal/vertical. Particularly, the Lorentz force (LF) changes in the central/peripheral region had a downward/upward and inward direction, meaning that the local pressure from the upper atmosphere was enhanced/released. It indicates that the LF changes might be responsible for the penumbra changes. These observations can be well explained as the photospheric response to the coronal field reconstruction within the framework of the magnetic implosion theory and the back reaction model of flares.

Initial Atomic Motion Immediately Following Femtosecond-Laser Excitation in Phase-Change Materials.

PubMed

Matsubara, E; Okada, S; Ichitsubo, T; Kawaguchi, T; Hirata, A; Guan, P F; Tokuda, K; Tanimura, K; Matsunaga, T; Chen, M W; Yamada, N

2016-09-23

Despite the fact that phase-change materials are widely used for data storage, no consensus exists on the unique mechanism of their ultrafast phase change and its accompanied large and rapid optical change. By using the pump-probe observation method combining a femtosecond optical laser and an x-ray free-electron laser, we substantiate experimentally that, in both GeTe and Ge_{2}Sb_{2}Te_{5} crystals, rattling motion of mainly Ge atoms takes place with keeping the off-center position just after femtosecond-optical-laser irradiation, which eventually leads to a higher symmetry or disordered state. This very initial rattling motion in the undistorted lattice can be related to instantaneous optical change due to the loss of resonant bonding that characterizes GeTe-based phase change materials. Based on the amorphous structure derived by first-principles molecular dynamics simulation, we infer a plausible ultrafast amorphization mechanism via nonmelting.

Rapid realist review of the evidence: achieving lasting change when mental health rehabilitation staff undertake recovery-oriented training.

PubMed

Gee, Melanie; Bhanbhro, Sadiq; Cook, Sarah; Killaspy, Helen

2017-08-01

The aim of this study was to identify the factors contributing to lasting change in practice following a recovery-based training intervention for inpatient mental health rehabilitation staff. Staff training may help nurses and other staff groups in inpatient mental health rehabilitative settings to increase their recovery-oriented practice. There are no published reviews on the effectiveness of such training and few long-term evaluations. This review informed a realist evaluation of a specific intervention (GetREAL). Rapid realist review methodology was used to generate and prioritize programme theories. ASSIA, CINAHL, Cochrane Library, Medline, PsycINFO, Scopus, Web of Science and grey literature searches were performed in September 2014-March 2015 with no date restrictions. Stakeholders suggested further documents. GetREAL project documentation was consulted. Programme theory development took place iteratively with literature identification. Stakeholders validated and prioritized emerging programme theories and the prioritized theories were refined using literature case studies. Fifty-one relevant documents fed into 49 programme theories articulating seven mechanisms for lasting change. Prioritized mechanisms were: staff receptiveness to change; and staff feeling encouraged, motivated and supported by colleagues and management to change. Seven programme theories were prioritized and refined using data from four case studies. Lasting change can be facilitated by collaborative action planning, regular collaborative meetings, appointing a change agent, explicit management endorsement and prioritization and modifying organizational structures. Conversely, a challenging organizational climate, or a prevalence of 'change fatigue', may block change. Pre-intervention exploration may help identify any potential barriers to embedding recovery in the organizational culture. © 2016 John Wiley & Sons Ltd.

Thermally Tunable Hydrogels Displaying Angle-Independent Structural Colors.

PubMed

Ohtsuka, Yumiko; Seki, Takahiro; Takeoka, Yukikazu

2015-12-14

We report the preparation of thermally tunable hydrogels displaying angle-independent structural colors. The porous structures were formed with short-range order using colloidal amorphous array templates and a small amount of carbon black (CB). The resultant porous hydrogels prepared using colloidal amorphous arrays without CB appeared white, whereas the hydrogels with CB revealed bright structural colors. The brightly colored hydrogels rapidly changed hues in a reversible manner, and the hues varied widely depending on the water temperature. Moreover, the structural colors were angle-independent under diffusive lighting because of the isotropic nanostructure generated from the colloidal amorphous arrays. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Noise Rating Criteria for Elevated Rapid Transit Structures

DOT National Transportation Integrated Search

1980-05-01

The purpose of this report is to recommend criteria for rating the noise radiated from elevated rapid transit structures during train passages, so that different types of structures can be inter-compared with respect to their noise impact on the imme...

Magnetic assembly route to colloidal responsive photonic nanostructures.

PubMed

He, Le; Wang, Mingsheng; Ge, Jianping; Yin, Yadong

2012-09-18

Responsive photonic structures can respond to external stimuli by transmitting optical signals. Because of their important technological applications such as color signage and displays, biological and chemical sensors, security devices, ink and paints, military camouflage, and various optoelectronic devices, researchers have focused on developing these functional materials. Conventionally, self-assembled colloidal crystals containing periodically arranged dielectric materials have served as the predominant starting frameworks. Stimulus-responsive materials are incorporated into the periodic structures either as the initial building blocks or as the surrounding matrix so that the photonic properties can be tuned. Although researchers have proposed various versions of responsive photonic structures, the low efficiency of fabrication through self-assembly, narrow tunability, slow responses to the external stimuli, incomplete reversibility, and the challenge of integrating them into existing photonic devices have limited their practical application. In this Account, we describe how magnetic fields can guide the assembly of superparamagnetic colloidal building blocks into periodically arranged particle arrays and how the photonic properties of the resulting structures can be reversibly tuned by manipulating the external magnetic fields. The application of the external magnetic field instantly induces a strong magnetic dipole-dipole interparticle attraction within the dispersion of superparamagnetic particles, which creates one-dimensional chains that each contains a string of particles. The balance between the magnetic attraction and the interparticle repulsions, such as the electrostatic force, defines the interparticle separation. By employing uniform superparamagnetic particles of appropriate sizes and surface charges, we can create one-dimensional periodicity, which leads to strong optical diffraction. Acting remotely over a large distance, magnetic forces drove the rapid formation of colloidal photonic arrays with a wide range of interparticle spacing. They also allowed instant tuning of the photonic properties because they manipulated the interparticle force balance, which changed the orientation of the colloidal assemblies or their periodicity. This magnetically responsive photonic system provides a new platform for chromatic applications: these colloidal particles assemble instantly into ordered arrays with widely, rapidly, and reversibly tunable structural colors, which can be easily and rapidly fixed in a curable polymer matrix. Based on these unique features, we demonstrated many applications of this system, such as structural color printing, the fabrication of anticounterfeiting devices, switchable signage, and field-responsive color displays. We also extended this idea to rapidly organize uniform nonmagnetic building blocks into photonic structures. Using a stable ferrofluid of highly charged magnetic nanoparticles, we created virtual magnetic moments inside the nonmagnetic particles. This "magnetic hole" strategy greatly broadens the scope of the magnetic assembly approach to the fabrication of tunable photonic structures from various dielectric materials.

Quantifying Glacier Volume Change Using UAV-Derived Imagery and Structure from Motion Photogrammetry

NASA Astrophysics Data System (ADS)

Decker, C. R.; La Frenierre, J.

2017-12-01

Glaciers in the Tropical Andes, like those worldwide, are experiencing rapid ice volume loss due to climate change. Tropical areas are of significant interest in glacier studies because they are especially sensitive to climate change. Quantifying the rate of ice volume loss is important given their sensitivity to climate change and the importance of glacier meltwater for downstream human use. Past studies have found shrinking ice surfaces areas, but finding the actual rate of volume loss gives more information about how glaciers are reacting to climate change as well as the direct hydrological effects of ice volume loss. In this study we determined the rate of ice volume loss for a debris covered section of the Reschreiter Glacier and a portion of the clean ice tongue of the Hans Meyer Glacier on Volcán Chimborazo in Ecuador. Traditional geodetic approaches of measuring ice volume change, including the use of satellite-derived digital elevation models and airborne LIDAR, are difficult in this case due to the small size of Chimborazo's glaciers, frequently cloudy conditions, and limited local resources. Instead, we obtained imagery with an Unmanned Aerial Vehicle (UAV) and processed this imagery using Structure from Motion photogrammetry. Our results are used to evaluate the role of elevation and debris cover as Chimborazo's glaciers respond to climate change.

The Determinant Factors of Regional Development Toward Land Use Change in Deli Serdang

NASA Astrophysics Data System (ADS)

Lindarto, D.; Sirojuzilam; Badaruddin; Dwira

2017-03-01

The concept of regional development Mebidangro (Medan, Binjai, Deli Serdang, and Karo) creating neighboring region hinterland Medan city with Deli Serdang Regency especially in Tembung village, Percut Sei Tuan District. Population structure in Tembung shows occurrence condition of rural-urban change which seen from the sprawl land use change. The aim of the study is to reveal the genius locus as one of land use change factors. The study conducted with quantitative approach intended at obtaining variables which describing several factors forming land use change. Descriptive approach intended to give an idea, justification, and fact-finding with correct interpretation. Data collected through a purposive sampling of 300 respondents who have built the house between 2010 till 2014. With overlay figure/ground technique, scoring analysis, descriptive quantitative and SEM (Structural Equational Models) gained a result that place character/genius locus (p=0,007) potentially as one of the main land use change driving factors besides accessibility (p=0,039), infrastructure (p=0,005), social-economic p=0,038). Topographic (p=0,663) was inversely potentially. The implication of the findings is required intensive control in space utilization considering the rapid change in land use transformation that tend to have the negative impact of urban sprawl.

Changes in Nannoplankton Assemblages during the recovery of the Paleocene Eocene Thermal Maximum (PETM)

NASA Astrophysics Data System (ADS)

Grey, J. A.; Bralower, T. J.; Self-Trail, J. M.

2016-12-01

The recovery interval of the Paleocene Eocene Thermal Maximum (PETM) presents an opportunity to examine how organisms adapt to environmental change after a rapid global warming event. Calcareous nannoplankton survived the PETM, but we lack an understanding of how long it took for assemblages to adapt to a changing climate and the millennial-scale changes in their ecology. Here, we present the first high-resolution record of nannoplankton community change during the PETM recovery using a global data set (United States Geological Survey (USGS) Wilson Lake core, USGS Cam-Dor core, Ocean Drilling Program (ODP) Sites 690, 1265, and 1209) to assess millennial-scale assemblage change across space and time. Preliminary multivariate analyses on assemblage changes at Wilson Lake demonstrate that within 20,000 years after the onset, the structure of nannoplankton communities shifts from an assemblage dominated by warm eutrophic specialists to one dominated by eutrophic low salinity specialists. In the late recovery, ubiquitous taxa dominate assemblages, suggesting that the shelf environment became favorable for generalists. The latest part of the recovery is marked by a slight increase in oligotrophic specialists, indicating that the shelf became less eutrophic into the early Eocene. Overall, these analyses suggest that assemblages changed rapidly in response to cooling and changing ocean circulation during the early recovery of the PETM. Future analyses will build on these data by comparing assemblage change from other PETM coastal and open ocean sites. These analyses will help us better understand the spatial and temporal changes of nannoplankton communities on a global scale, lessons that can inform how nannoplankton will respond to future climate change.

Coral community response to bleaching on a highly disturbed reef

PubMed Central

Guest, J. R.; Low, J.; Tun, K.; Wilson, B.; Ng, C.; Raingeard, D.; Ulstrup, K. E.; Tanzil, J. T. I.; Todd, P. A.; Toh, T. C.; McDougald, D.; Chou, L. M.; Steinberg, P. D.

2016-01-01

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress. PMID:26876092

Coral community response to bleaching on a highly disturbed reef.

PubMed

Guest, J R; Low, J; Tun, K; Wilson, B; Ng, C; Raingeard, D; Ulstrup, K E; Tanzil, J T I; Todd, P A; Toh, T C; McDougald, D; Chou, L M; Steinberg, P D

2016-02-15

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

Coral community response to bleaching on a highly disturbed reef

NASA Astrophysics Data System (ADS)

Guest, J. R.; Low, J.; Tun, K.; Wilson, B.; Ng, C.; Raingeard, D.; Ulstrup, K. E.; Tanzil, J. T. I.; Todd, P. A.; Toh, T. C.; McDougald, D.; Chou, L. M.; Steinberg, P. D.

2016-02-01

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

Adverse Impact of Electromagnetic Radiation on Urban Environment and Natural Resources using Optical Sensors

NASA Astrophysics Data System (ADS)

Kumar, Pawan; Katiyar, Swati; Rani, Meenu

2016-07-01

We are living in the age of a rapidly growing population and changing environmental conditions with an advance technical capacity.This has resulted in wide spread land cover change. One of the main causes for increasing urban heat is that more than half of the world's population lives in a rapidly growing urbanized environment. Satellite data can be highly useful to map change in land cover and other environmental phenomena with the passage of time. Among several human-induced environmental and urban thermal problems are reported to be negatively affecting urban residents in many ways. The built-up structures in urbanized areas considerably alter land cover thereby affecting thermal energy flow which leads to development of elevated surface and air temperature. The phenomenon Urban Heat Island implies 'island' of high temperature in cities, surrounded by relatively lower temperature in rural areas. The UHI for the temporal period is estimated using geospatial techniques which are then utilized for the impact assessment on climate of the surrounding regions and how it reduce the sustainability of the natural resources like air, vegetation. The present paper describes the methodology and resolution dynamic urban heat island change on climate using the geospatial approach. NDVI were generated using day time LANDSAT ETM+ image of 1990, 2000 and 2013. Temperature of various land use and land cover categories was estimated. Keywords: NDVI, Surface temperature, Dynamic changes.

Changing roles of propagule, climate, and land use during extralimital colonization of a rose chafer beetle

NASA Astrophysics Data System (ADS)

Horak, Jakub; Hui, Cang; Roura-Pascual, Núria; Romportl, Dusan

2013-04-01

Regardless of their ecosystem functions, some insects are threatened when facing environmental changes and disturbances, while others become extremely successful. It is crucial for successful conservation to differentiate factors supporting species' current distributions from those triggering range dynamics. Here, we studied the sudden extralimital colonization of the rose chafer beetle, Oxythyrea funesta, in the Czech Republic. Specifically, we depicted the range expansion using accumulated historical records of first known occurrences and then explained the colonization events using five transformed indices depicting changes in local propagule pressure (LPP), climate, land use, elevation, and landscape structure. The slow occupancy increase of O. funesta before 1990 changed to a phase of rapid occupancy increase after 1990, driven not only by changes in the environment (climate and land use) but also by the spatial accumulation of LPP. Climate was also found to play a significant role but only during the niche-filling stage before 1990, while land use became important during the phase of rapid expansion after 1990. Inland waters (e.g., riparian corridors) also contributed substantially to the spread in the Czech Republic. Our method of using spatially transformed variables to explain the colonization events provides a novel way of detecting factors triggering range dynamics. The results highlight the importance of LPP in driving sudden occupancy increase of extralimital species and recommend the use of LPP as an important predictor for modeling range dynamics.

Resilient terrestrial ecosystems at the Paleocene-Eocene Thermal Maximum (Invited)

NASA Astrophysics Data System (ADS)

Wing, S.

2010-12-01

The Paleocene-Eocene Thermal Maximum (PETM) was an interval of global warming lasting ~200 ka that began ~56 Ma. Global temperature rose 5-8 °C in association with the emission of thousands of Pg of carbon into the ocean-atmosphere system. PETM rocks and fossils are extensively exposed in the SE Bighorn Basin of Wyoming, where the event is represented by ~40 m of fluvial rocks. Fossil plants demonstrate a rapid and nearly complete turnover in floral composition that also suggests a change in the structure of vegetation. Floras collected from the last ~50 ka of the Paleocene are composed of Platanaceae (sycamores), Betulaceae (birches), Fagaceae (oaks), Lauraceae (laurels), Juglandaceae (walnuts), Cercidiphyllaceae (katsura), Taxodiaceae (dawn redwood), and Arecaceae (palms), among others. Many of these families are most diverse and abundant today in temperate to subtropical, mid-latitude forests. During the body of the carbon isotope excursion (CIE) associated with the PETM fossil floras have a completely different composition. All of the latest Paleocene plant types are absent, except for palms, and instead the floras are dominated by Fabaceae (bean family). Other taxa include Sapindaceae (soapberry), Annonaceae (paw-paw), and Hernandiaceae. Where living relatives are known, they live in dry tropical forests of Central and South America. This floral composition is maintained through the ~30 m of section representing the ~110 ka-long body of the CIE, the same interval characterized by dwarfed mammalian faunas. During the recovery phase of the CIE most of the latest Paleocene plants returned to the area of study, although some new taxa appeared, apparently coming in from Europe or Asia. The distinctive PETM floral types are not seen after the recovery phase of the CIE. Change in floral composition during the PETM apparently represents regional extirpations of populations of plants that preferred warm, mesic conditions, and northward range extensions of plants that preferred dry tropical climates. This process was reversed at the end of the PETM. Although characteristics of PETM vegetation cannot be assessed directly, the distribution of living relatives is consistent with the idea that PETM vegetation was more water-stressed and more open than pre- and post-PETM vegetation. This is also matches inference from paleosol features. The radical change in composition and probable structure of vegetation across the PETM is particularly notable in light of the low extinction rates at this time. Although there is strong evidence of rapid range change and rapid evolution, the increase in temperature and decrease in precipitation do not appear to have exceeded the capacity of lineages to respond, even though the PETM is cited as an example of geologically rapid environmental change.

Effects of Rapid Weight Loss on Systemic and Adipose Tissue Inflammation and Metabolism in Obese Postmenopausal Women.

PubMed

Alemán, José O; Iyengar, Neil M; Walker, Jeanne M; Milne, Ginger L; Da Rosa, Joel Correa; Liang, Yupu; Giri, Dilip D; Zhou, Xi Kathy; Pollak, Michael N; Hudis, Clifford A; Breslow, Jan L; Holt, Peter R; Dannenberg, Andrew J

2017-06-01

Obesity is associated with subclinical white adipose tissue inflammation, as defined by the presence of crown-like structures (CLSs) consisting of dead or dying adipocytes encircled by macrophages. In humans, bariatric surgery-induced weight loss leads to a decrease in CLSs, but the effects of rapid diet-induced weight loss on CLSs and metabolism are unclear. To determine the effects of rapid very-low-calorie diet-induced weight loss on CLS density, systemic biomarkers of inflammation, and metabolism in obese postmenopausal women. Prospective cohort study. Rockefeller University Hospital, New York, NY. Ten obese, postmenopausal women with a mean age of 60.6 years (standard deviation, ±3.6 years). Effects on CLS density and gene expression in abdominal subcutaneous adipose tissue, cardiometabolic risk factors, white blood count, circulating metabolites, and oxidative stress (urinary isoprostane-M) were measured. Obese subjects lost approximately 10% body weight over a mean of 46 days. CLS density increased in subcutaneous adipose tissue without an associated increase in proinflammatory gene expression. Weight loss was accompanied by decreased fasting blood levels of high-sensitivity C-reactive protein, glucose, lactate, and kynurenine, and increased circulating levels of free fatty acids, glycerol, β -hydroxybutyrate, and 25 hydroxyvitamin D. Levels of urinary isoprostane-M declined. Rapid weight loss stimulated lipolysis and an increase in CLS density in subcutaneous adipose tissue in association with changes in levels of circulating metabolites, and improved systemic biomarkers of inflammation and insulin resistance. The observed change in levels of metabolites ( i.e. , lactate, β -hydroxybutyrate, 25 hydroxyvitamin D) may contribute to the anti-inflammatory effect of rapid weight loss.

Effects of Rapid Weight Loss on Systemic and Adipose Tissue Inflammation and Metabolism in Obese Postmenopausal Women

PubMed Central

Iyengar, Neil M.; Walker, Jeanne M.; Milne, Ginger L.; Da Rosa, Joel Correa; Liang, Yupu; Giri, Dilip D.; Zhou, Xi Kathy; Pollak, Michael N.; Hudis, Clifford A.; Breslow, Jan L.; Holt, Peter R.; Dannenberg, Andrew J.

2017-01-01

Context: Obesity is associated with subclinical white adipose tissue inflammation, as defined by the presence of crown-like structures (CLSs) consisting of dead or dying adipocytes encircled by macrophages. In humans, bariatric surgery-induced weight loss leads to a decrease in CLSs, but the effects of rapid diet-induced weight loss on CLSs and metabolism are unclear. Objective: To determine the effects of rapid very-low-calorie diet-induced weight loss on CLS density, systemic biomarkers of inflammation, and metabolism in obese postmenopausal women. Design: Prospective cohort study. Setting: Rockefeller University Hospital, New York, NY. Participants: Ten obese, postmenopausal women with a mean age of 60.6 years (standard deviation, ±3.6 years). Main Outcome Measures: Effects on CLS density and gene expression in abdominal subcutaneous adipose tissue, cardiometabolic risk factors, white blood count, circulating metabolites, and oxidative stress (urinary isoprostane-M) were measured. Results: Obese subjects lost approximately 10% body weight over a mean of 46 days. CLS density increased in subcutaneous adipose tissue without an associated increase in proinflammatory gene expression. Weight loss was accompanied by decreased fasting blood levels of high-sensitivity C-reactive protein, glucose, lactate, and kynurenine, and increased circulating levels of free fatty acids, glycerol, β-hydroxybutyrate, and 25 hydroxyvitamin D. Levels of urinary isoprostane-M declined. Conclusion: Rapid weight loss stimulated lipolysis and an increase in CLS density in subcutaneous adipose tissue in association with changes in levels of circulating metabolites, and improved systemic biomarkers of inflammation and insulin resistance. The observed change in levels of metabolites (i.e., lactate, β-hydroxybutyrate, 25 hydroxyvitamin D) may contribute to the anti-inflammatory effect of rapid weight loss. PMID:29264516

Effects of landscape change on fish assemblage structure in a rapidly growing metropolitan area in North Carolina, USA

USGS Publications Warehouse

Kennen, J.G.; Chang, M.; Tracy, B.H.

2005-01-01

We evaluated a comprehensive set of natural and land-use attributes that represent the major facets of urban development at fish monitoring sites in the rapidly growing Raleigh-Durham, North Carolina metropolitan area. We used principal component and correlation analysis to obtain a nonredundant subset of variables that extracted most variation in the complete set. With this subset of variables, we assessed the effect of urban growth on fish assemblage structure. We evaluated variation in fish assemblage structure with nonmetric multidimensional scaling (NMDS). We used correlation analysis to identify the most important environmental and landscape variables associated with significant NMDS axes. The second NMDS axis is related to many indices of land-use/land-cover change and habitat. Significant correlations with proportion of largest forest patch to total patch size (r = -0.460, P < 0.01), diversity of patch types (r = 0.554, P < 0.001), and population density (r = 0.385, P < 0.05) helped identify NMDS axis 2 as a disturbance gradient. Positive and negative correlations between the abundance of redbreast sunfish Lepomis auritus and bluehead chub Nocomis leptocephalus, respectively, and NMDS axis 2 also were evident. The North Carolina index of biotic integrity and many of its component metrics were highly correlated with urbanization. These results indicate that aquatic ecosystem integrity would be optimized by a comprehensive integrated management strategy that includes the preservation of landscape function by maximizing the conservation of contiguous tracts of forested lands and vegetative cover in watersheds. ?? 2005 by the American Fisheries Society.

The Radius and Entropy of a Magnetized, Rotating, Fully Convective Star: Analysis with Depth-dependent Mixing Length Theories

NASA Astrophysics Data System (ADS)

Ireland, Lewis G.; Browning, Matthew K.

2018-04-01

Some low-mass stars appear to have larger radii than predicted by standard 1D structure models; prior work has suggested that inefficient convective heat transport, due to rotation and/or magnetism, may ultimately be responsible. We examine this issue using 1D stellar models constructed using Modules for Experiments in Stellar Astrophysics (MESA). First, we consider standard models that do not explicitly include rotational/magnetic effects, with convective inhibition modeled by decreasing a depth-independent mixing length theory (MLT) parameter α MLT. We provide formulae linking changes in α MLT to changes in the interior specific entropy, and hence to the stellar radius. Next, we modify the MLT formulation in MESA to mimic explicitly the influence of rotation and magnetism, using formulations suggested by Stevenson and MacDonald & Mullan, respectively. We find rapid rotation in these models has a negligible impact on stellar structure, primarily because a star’s adiabat, and hence its radius, is predominantly affected by layers near the surface; convection is rapid and largely uninfluenced by rotation there. Magnetic fields, if they influenced convective transport in the manner described by MacDonald & Mullan, could lead to more noticeable radius inflation. Finally, we show that these non-standard effects on stellar structure can be fabricated using a depth-dependent α MLT: a non-magnetic, non-rotating model can be produced that is virtually indistinguishable from one that explicitly parameterizes rotation and/or magnetism using the two formulations above. We provide formulae linking the radially variable α MLT to these putative MLT reformulations.

Stimulation Induced Changes in Frog Neuromuscular Junctions: A Quantitative Ultrastructural Comparison of Rapid-Frozen and Chemically Fixed Nerve Terminals

DTIC Science & Technology

1984-03-06

study was conducted to determine the presynaptic morphological changes due to neural activity in rapidly stimulated neuromuscular junctions...Control preparations were unstimulated and preserved either by chemical fixation or rapid-freezing. This study provides evidence that most of the...tissue. The rapid-frozen preparations in the present study showed, in addition, that rapid stimulation produces an increase in synaptic vesicle

Planetary perspective. Report of Working Group Number 4

NASA Technical Reports Server (NTRS)

Rossbacher, L. A.

1985-01-01

The study of global megageomorphology from a planetary perspective requires that, philosophically, we view the Earth as a planet like any other; one among a number of bodies of varied size and composition which, together with the Sun, form the Solar System. A first step in the study of the Earth from the planetary perspective is the development of global distribution maps of surface factors as landforms, tectonics, and of key processes operating on Earth. Data of other types, such as gravity and magnetism, should also be included and, so far as possible, multiple data sets should be developed. The compilation of maps would serve as a catalyst for research and a basis for interpretation. They could be used scientifically to document changes such as glacial variations and their relationships to climate, volcanic eruptions and their effects, and coastal alterations. Slow and rapid changes should be studied together with the relationships between scale and the rapidity of change. A study of the relationship of geomorphology (i.e., surficial processes) to lithology and structure is needed. The planetary perspective can also help in the identification and investigation of exotic features such as suspect terrains.

An Inlet Distortion Assessment During Aircraft Departures at High Angle of Attack for an F/A-18A Aircraft

NASA Technical Reports Server (NTRS)

Steenken, William G.; Williams, John G.; Yuhas, Andrew J.; Walsh, Kevin R.

1997-01-01

The F404-GE-400-powered F/A-18A High Alpha Research Vehicle (HARV) was used to examine the quality of inlet airflow during departed flight maneuvers, that is, during flight outside the normal maneuvering envelope where control surfaces have little or no effectiveness. Six nose-left and six nose-right departures were initiated at Mach numbers between 0.3 and 0.4 at an altitude of 35 kft. The entry yaw rates were approximately 40 to 90 deg/sec. Engine surges were encountered during three of the nose-left and one of the nose-right departures. Time-variant inlet-total-pressure distortion levels at the engine face did not significantly exceed those at maximum angle-of-attack and sideslip maneuvers during controlled flight. Surges caused by inlet distortion levels resulted from a combination of high levels of inlet distortion and rapid changes in aircraft position. These rapid changes indicate a combination of engine support and gyroscopic loads being applied to the engine structure that impact the aerodynamic stability of the compressor through changes in the rotor-to-case clearances. This document presents the slides from an oral presentation.

MPC Design for Rapid Pump-Attenuation and Expedited Hyperglycemia Response to Treat T1DM with an Artificial Pancreas

PubMed Central

Gondhalekar, Ravi; Dassau, Eyal; Doyle, Francis J.

2016-01-01

The design of a Model Predictive Control (MPC) strategy for the closed-loop operation of an Artificial Pancreas (AP) for treating Type 1 Diabetes Mellitus (T1DM) is considered in this paper. The contribution of this paper is to propose two changes to the usual structure of the MPC problems typically considered for control of an AP. The first proposed change is to replace the symmetric, quadratic input cost function with an asymmetric, quadratic function, allowing negative control inputs to be penalized less than positive ones. This facilitates rapid pump-suspensions in response to predicted hypoglycemia, while simultaneously permitting the design of a conservative response to hyperglycemia. The second proposed change is to penalize the velocity of the predicted glucose level, where this velocity penalty is based on a cost function that is again asymmetric, but additionally state-dependent. This facilitates the accelerated response to acute, persistent hyperglycemic events, e.g., as induced by unannounced meals. The novel functionality is demonstrated by numerical examples, and the efficacy of the proposed MPC strategy verified using the University of Padova/Virginia metabolic simulator. PMID:28479660

Changes in Sensory Evoked Responses Coincide with Rapid Improvement in Speech Identification Performance

ERIC Educational Resources Information Center

Alain, Claude; Campeanu, Sandra; Tremblay, Kelly

2010-01-01

Perceptual learning is sometimes characterized by rapid improvements in performance within the first hour of training (fast perceptual learning), which may be accompanied by changes in sensory and/or response pathways. Here, we report rapid physiological changes in the human auditory system that coincide with learning during a 1-hour test session…

Geometric structure of thin SiO xN y films on Si(100)

NASA Astrophysics Data System (ADS)

Behrens, K.-M.; Klinkenberg, E.-D.; Finster, J.; Meiwes-Broer, K.-H.

1998-05-01

Thin films of amorphous stoichometric SiO xN y are deposited on radiation-heated Si(100) by rapid thermal low-pressure chemical vapour deposition. We studied the whole range of possible compositions. In order to determine the geometric structure, we used EXAFS and photoelectron spectroscopy. Tetrahedrons constitute the short-range units with a central Si atom connected to N and O. The distribution of the possible tetrahedrons can be described by a mixture of the Random Bonding Model and the Random Mixture Model. For low oxygen contents x/( x+ y)≤0.3, the geometric structure of the film is almost the structure of a-Si 3N 4, with the oxygen preferably on top of Si-N 3 triangles. Higher oxygen contents induce changes in the bond lengths, bond angles and coordination numbers.

Low resolution solution structure of HAMLET and the importance of its alpha-domains in tumoricidal activity.

PubMed

Ho, C S James; Rydstrom, Anna; Manimekalai, Malathy Sony Subramanian; Svanborg, Catharina; Grüber, Gerhard

2012-01-01

HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is the first member in a new family of protein-lipid complexes with broad tumoricidal activity. Elucidating the molecular structure and the domains crucial for HAMLET formation is fundamental for understanding its tumoricidal function. Here we present the low-resolution solution structure of the complex of oleic acid bound HAMLET, derived from small angle X-ray scattering data. HAMLET shows a two-domain conformation with a large globular domain and an extended part of about 2.22 nm in length and 1.29 nm width. The structure has been superimposed into the related crystallographic structure of human α-lactalbumin, revealing that the major part of α-lactalbumin accommodates well in the shape of HAMLET. However, the C-terminal residues from L105 to L123 of the crystal structure of the human α-lactalbumin do not fit well into the HAMLET structure, resulting in an extended conformation in HAMLET, proposed to be required to form the tumoricidal active HAMLET complex with oleic acid. Consistent with this low resolution structure, we identified biologically active peptide epitopes in the globular as well as the extended domains of HAMLET. Peptides covering the alpha1 and alpha2 domains of the protein triggered rapid ion fluxes in the presence of sodium oleate and were internalized by tumor cells, causing rapid and sustained changes in cell morphology. The alpha peptide-oleate bound forms also triggered tumor cell death with comparable efficiency as HAMLET. In addition, shorter peptides corresponding to those domains are biologically active. These findings provide novel insights into the structural prerequisites for the dramatic effects of HAMLET on tumor cells.

Low Resolution Solution Structure of HAMLET and the Importance of Its Alpha-Domains in Tumoricidal Activity

PubMed Central

Ho CS, James; Rydstrom, Anna; Manimekalai, Malathy Sony Subramanian; Svanborg, Catharina; Grüber, Gerhard

2012-01-01

HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is the first member in a new family of protein-lipid complexes with broad tumoricidal activity. Elucidating the molecular structure and the domains crucial for HAMLET formation is fundamental for understanding its tumoricidal function. Here we present the low-resolution solution structure of the complex of oleic acid bound HAMLET, derived from small angle X-ray scattering data. HAMLET shows a two-domain conformation with a large globular domain and an extended part of about 2.22 nm in length and 1.29 nm width. The structure has been superimposed into the related crystallographic structure of human α-lactalbumin, revealing that the major part of α-lactalbumin accommodates well in the shape of HAMLET. However, the C-terminal residues from L105 to L123 of the crystal structure of the human α-lactalbumin do not fit well into the HAMLET structure, resulting in an extended conformation in HAMLET, proposed to be required to form the tumoricidal active HAMLET complex with oleic acid. Consistent with this low resolution structure, we identified biologically active peptide epitopes in the globular as well as the extended domains of HAMLET. Peptides covering the alpha1 and alpha2 domains of the protein triggered rapid ion fluxes in the presence of sodium oleate and were internalized by tumor cells, causing rapid and sustained changes in cell morphology. The alpha peptide-oleate bound forms also triggered tumor cell death with comparable efficiency as HAMLET. In addition, shorter peptides corresponding to those domains are biologically active. These findings provide novel insights into the structural prerequisites for the dramatic effects of HAMLET on tumor cells. PMID:23300861

Investigation of low-loss spectra and near-edge fine structure of polymers by PEELS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heckmann, W.

Transmission electron microscopy has changed from a purely imaging method to an analytical method. This has been facilitated particularly by equipping electron microscopes with energy filters and with parallel electron energy loss spectrometers (PEELS). Because of their relatively high energy resolution (1 to 2 eV) they provide information not only on the elements present but also on the type of bonds between the molecular groups. Polymers are radiation sensitive and the molecular bonds change as the spectrum is being recorded. This can be observed with PEEL spectrometers that are able to record spectra with high sensitivity and in rapid succession.

Economic Globalization and a Nuclear Renaissance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Thomas W; Johnson, Wayne L; Parker, Brian M

2001-10-22

The phenomenon of globalization has become increasingly well recognized, documented, and analyzed in the last several years. Globalization, the integration of markets and intra-firm competition on a worldwide basis, involves complex behavioral and mindset changes within a firm that facilitate global competition. The changes revolve around efficient information flow and rapid deployment of technology. The objective of this report is to examine the probable characteristics of a global nuclear renaissance and its broad implications for industry structure and export control relative to nuclear technology. The question of how a modern renaissance would affect the trend toward globalization of the nuclearmore » industry is addressed.« less

Revealing the hidden networks of interaction in mobile animal groups allows prediction of complex behavioral contagion.

PubMed

Rosenthal, Sara Brin; Twomey, Colin R; Hartnett, Andrew T; Wu, Hai Shan; Couzin, Iain D

2015-04-14

Coordination among social animals requires rapid and efficient transfer of information among individuals, which may depend crucially on the underlying structure of the communication network. Establishing the decision-making circuits and networks that give rise to individual behavior has been a central goal of neuroscience. However, the analogous problem of determining the structure of the communication network among organisms that gives rise to coordinated collective behavior, such as is exhibited by schooling fish and flocking birds, has remained almost entirely neglected. Here, we study collective evasion maneuvers, manifested through rapid waves, or cascades, of behavioral change (a ubiquitous behavior among taxa) in schooling fish (Notemigonus crysoleucas). We automatically track the positions and body postures, calculate visual fields of all individuals in schools of ∼150 fish, and determine the functional mapping between socially generated sensory input and motor response during collective evasion. We find that individuals use simple, robust measures to assess behavioral changes in neighbors, and that the resulting networks by which behavior propagates throughout groups are complex, being weighted, directed, and heterogeneous. By studying these interaction networks, we reveal the (complex, fractional) nature of social contagion and establish that individuals with relatively few, but strongly connected, neighbors are both most socially influential and most susceptible to social influence. Furthermore, we demonstrate that we can predict complex cascades of behavioral change at their moment of initiation, before they actually occur. Consequently, despite the intrinsic stochasticity of individual behavior, establishing the hidden communication networks in large self-organized groups facilitates a quantitative understanding of behavioral contagion.

Learning new color names produces rapid increase in gray matter in the intact adult human cortex

PubMed Central

Kwok, Veronica; Niu, Zhendong; Kay, Paul; Zhou, Ke; Mo, Lei; Jin, Zhen; So, Kwok-Fai; Tan, Li Hai

2011-01-01

The human brain has been shown to exhibit changes in the volume and density of gray matter as a result of training over periods of several weeks or longer. We show that these changes can be induced much faster by using a training method that is claimed to simulate the rapid learning of word meanings by children. Using whole-brain magnetic resonance imaging (MRI) we show that learning newly defined and named subcategories of the universal categories green and blue in a period of 2 h increases the volume of gray matter in V2/3 of the left visual cortex, a region known to mediate color vision. This pattern of findings demonstrates that the anatomical structure of the adult human brain can change very quickly, specifically during the acquisition of new, named categories. Also, prior behavioral and neuroimaging research has shown that differences between languages in the boundaries of named color categories influence the categorical perception of color, as assessed by judgments of relative similarity, by response time in alternative forced-choice tasks, and by visual search. Moreover, further behavioral studies (visual search) and brain imaging studies have suggested strongly that the categorical effect of language on color processing is left-lateralized, i.e., mediated by activity in the left cerebral hemisphere in adults (hence “lateralized Whorfian” effects). The present results appear to provide a structural basis in the brain for the behavioral and neurophysiologically observed indices of these Whorfian effects on color processing. PMID:21464316

Drivers of tall shrub proliferation adjacent to the Dempster Highway, Northwest Territories, Canada

NASA Astrophysics Data System (ADS)

Cameron, Emily A.; Lantz, Trevor C.

2016-04-01

Arctic ecosystems are undergoing rapid changes as a result of climate warming and more frequent disturbances. Disturbances can have particularly large effects on high-latitude ecosystems when ecosystem structure and function is controlled by strong feedbacks between soil conditions, vegetation, and ground thermal regime. In this study we investigated the impact of road construction and maintenance on vegetation structure and biomass along the Dempster Highway where it crosses the Peel Plateau in the Northwest Territories. To explore drivers of tall shrub proliferation and to quantify shrub proliferation in this region of continuous permafrost, greyscale air photos (1975) and Quickbird satellite imagery (2008) were used to map landcover change within two 0.6 km2 belts next to the road and two 0.6 km2 belts 500 m away from the road. Maps showing areas where: 1) tall shrubs expanded, and 2) dwarf shrub tundra resisted invasion were then used to select field sites where a suite of biophysical variables were measured. Rapid tall shrub proliferation and greater biomass adjacent to the road indicate that disturbance can facilitate vegetation change in tundra environments. Our field data also suggests that increased shrub proliferation adjacent to the road was caused by greater soil moisture. Tall shrub proliferation adjacent to the road occurred at lower elevation sites characterized by wetter soils with thicker organic layers. Areas that resisted tall shrub encroachment were located at higher elevations and had drier soils with thin organic layers. Our observations also support previous work illustrating that tall shrub expansion next to the highway promotes strong positive feedbacks to ongoing shrub growth and proliferation.

Revealing the hidden networks of interaction in mobile animal groups allows prediction of complex behavioral contagion

PubMed Central

Rosenthal, Sara Brin; Twomey, Colin R.; Hartnett, Andrew T.; Wu, Hai Shan; Couzin, Iain D.

2015-01-01

Coordination among social animals requires rapid and efficient transfer of information among individuals, which may depend crucially on the underlying structure of the communication network. Establishing the decision-making circuits and networks that give rise to individual behavior has been a central goal of neuroscience. However, the analogous problem of determining the structure of the communication network among organisms that gives rise to coordinated collective behavior, such as is exhibited by schooling fish and flocking birds, has remained almost entirely neglected. Here, we study collective evasion maneuvers, manifested through rapid waves, or cascades, of behavioral change (a ubiquitous behavior among taxa) in schooling fish (Notemigonus crysoleucas). We automatically track the positions and body postures, calculate visual fields of all individuals in schools of ∼150 fish, and determine the functional mapping between socially generated sensory input and motor response during collective evasion. We find that individuals use simple, robust measures to assess behavioral changes in neighbors, and that the resulting networks by which behavior propagates throughout groups are complex, being weighted, directed, and heterogeneous. By studying these interaction networks, we reveal the (complex, fractional) nature of social contagion and establish that individuals with relatively few, but strongly connected, neighbors are both most socially influential and most susceptible to social influence. Furthermore, we demonstrate that we can predict complex cascades of behavioral change at their moment of initiation, before they actually occur. Consequently, despite the intrinsic stochasticity of individual behavior, establishing the hidden communication networks in large self-organized groups facilitates a quantitative understanding of behavioral contagion. PMID:25825752

The Rapid Ice Sheet Change Observatory (RISCO)

NASA Astrophysics Data System (ADS)

Morin, P.; Howat, I. M.; Ahn, Y.; Porter, C.; McFadden, E. M.

2010-12-01

The recent expansion of observational capacity from space has revealed dramatic, rapid changes in the Earth’s ice cover. These discoveries have fundamentally altered how scientists view ice-sheet change. Instead of just slow changes in snow accumulation and melting over centuries or millennia, important changes can occur in sudden events lasting only months, weeks, or even a single day. Our understanding of these short time- and space-scale processes, which hold important implications for future global sea level rise, has been impeded by the low temporal and spatial resolution, delayed sensor tasking, incomplete coverage, inaccessibility and/or high cost of data available to investigators. New cross-agency partnerships and data access policies provide the opportunity to dramatically improve the resolution of ice sheet observations by an order of magnitude, from timescales of months and distances of 10’s of meters, to days and meters or less. Advances in image processing technology also enable application of currently under-utilized datasets. The infrastructure for systematically gathering, processing, analyzing and distributing these data does not currently exist. Here we present the development of a multi-institutional, multi-platform observatory for rapid ice change with the ultimate objective of helping to elucidate the relevant timescales and processes of ice sheet dynamics and response to climate change. The Rapid Ice Sheet Observatory (RISCO) gathers observations of short time- and space-scale Cryosphere events and makes them easily accessible to investigators, media and general public. As opposed to existing data centers, which are structured to archive and distribute diverse types of raw data to end users with the specialized software and skills to analyze them, RISCO focuses on three types of geo-referenced raster (image) data products in a format immediately viewable with commonly available software. These three products are (1) sequences of images and image animations from the ice sheet scale down to scales of meters, (2) maps of ice flow velocity and acceleration and (3) digital elevation models and elevation change maps. These products are created both from user-tasked data acquisitions and from a decade of archived data. An online user interface will allow browsing of the data catalog, product ordering and requests for sensor tasking. Over the next few years, RISCO will develop into a long-term observational system, with an adaptable infrastructure to accommodate new sensors and currently unforeseeable demands. RISCO has the potential to greatly enhance observation of ice sheets, moving from ad hoc studies of past changes using whatever data happens to be available, to scalable, targeted, near-real time monitoring of events as they occur.

A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryant, M. J.; Skelton, J. M.; Hatcher, L. E.

Selective, robust and cost-effective chemical sensors for detecting small volatile-organic compounds (VOCs) have widespread applications in industry, healthcare and environmental monitoring. Here we design a Pt(II) pincer-Type material with selective absorptive and emissive responses to methanol and water. The yellow anhydrous form converts reversibly on a subsecond timescale to a red hydrate in the presence of parts-per-Thousand levels of atmospheric water vapour. Exposure to methanol induces a similarly-rapid and reversible colour change to a blue methanol solvate. Stable smart coatings on glass demonstrate robust switching over 10 4 cycles, and flexible microporous polymer membranes incorporating microcrystals of the complex showmore » identical vapochromic behaviour. The rapid vapochromic response can be rationalised from the crystal structure, and in combination with quantum-chemical modelling, we provide a complete microscopic picture of the switching mechanism. We discuss how this multiscale design approach can be used to obtain new compounds with tailored VOC selectivity and spectral responses.« less

Verification and Validation in a Rapid Software Development Process

NASA Technical Reports Server (NTRS)

Callahan, John R.; Easterbrook, Steve M.

1997-01-01

The high cost of software production is driving development organizations to adopt more automated design and analysis methods such as rapid prototyping, computer-aided software engineering (CASE) tools, and high-level code generators. Even developers of safety-critical software system have adopted many of these new methods while striving to achieve high levels Of quality and reliability. While these new methods may enhance productivity and quality in many cases, we examine some of the risks involved in the use of new methods in safety-critical contexts. We examine a case study involving the use of a CASE tool that automatically generates code from high-level system designs. We show that while high-level testing on the system structure is highly desirable, significant risks exist in the automatically generated code and in re-validating releases of the generated code after subsequent design changes. We identify these risks and suggest process improvements that retain the advantages of rapid, automated development methods within the quality and reliability contexts of safety-critical projects.

A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor

DOE PAGES

Bryant, M. J.; Skelton, J. M.; Hatcher, L. E.; ...

2017-11-27

Selective, robust and cost-effective chemical sensors for detecting small volatile-organic compounds (VOCs) have widespread applications in industry, healthcare and environmental monitoring. Here we design a Pt(II) pincer-Type material with selective absorptive and emissive responses to methanol and water. The yellow anhydrous form converts reversibly on a subsecond timescale to a red hydrate in the presence of parts-per-Thousand levels of atmospheric water vapour. Exposure to methanol induces a similarly-rapid and reversible colour change to a blue methanol solvate. Stable smart coatings on glass demonstrate robust switching over 10 4 cycles, and flexible microporous polymer membranes incorporating microcrystals of the complex showmore » identical vapochromic behaviour. The rapid vapochromic response can be rationalised from the crystal structure, and in combination with quantum-chemical modelling, we provide a complete microscopic picture of the switching mechanism. We discuss how this multiscale design approach can be used to obtain new compounds with tailored VOC selectivity and spectral responses.« less

Diagnosing the influence of model structure on the simulation of water, energy and carbon fluxes on bark beetle infested forests

NASA Astrophysics Data System (ADS)

Gochis, D. J.; Gutmann, E. D.; Brooks, P. D.; Reed, D. E.; Ewers, B. E.; Pendall, E.; Biederman, J. A.; Harpold, A. A.; Barnard, H. R.; Hu, J.

2011-12-01

Forest dynamics induced by insect infestation can have a significant, local impact on plant physiological regulation of water, energy and carbon fluxes. Rapid mortality succeeded by more gradually varying land cover changes are presently thought to initiate a cascade of changes to water, energy and carbon budgets at the forest stand scale. Initial model sensitivity results have suggested very strong changes in land-atmosphere exchanges of these variables. Specifically, model results from the Noah land surface model, a relatively simple model, have suggested that loss of transpiration function may result in a nearly 50% increase in seasonal soil moisture values and similar increases in runoff production for locations in the central Rocky Mountains. However, differing model structures, such as the representation of plant canopy architecture, snowpack dynamics, dynamic vegetation and hillslope hydrologic processes, may significantly confound the synthesis of results from different modeling systems. We assess the performance of new suite of model simulations from three different land surface models of differing model structures and complexity levels against a comprehensive set of field observations of land surface flux and state variables. The focus of the analysis is in diagnosing how model structure influences changes in energy, water and carbon budget partitioning prior to and following insect infestation. Specific emphasis in this presentation is placed on verifying variables that characterize top of canopy and within canopy energy and water fluxes. We conclude the presentation with a set of recommendations about the advantages and disadvantages of various model structures in their simulation of insect driven forest dynamics.

Visualization of nanocrystal breathing modes at extreme strains

NASA Astrophysics Data System (ADS)

Szilagyi, Erzsi; Wittenberg, Joshua S.; Miller, Timothy A.; Lutker, Katie; Quirin, Florian; Lemke, Henrik; Zhu, Diling; Chollet, Matthieu; Robinson, Joseph; Wen, Haidan; Sokolowski-Tinten, Klaus; Lindenberg, Aaron M.

2015-03-01

Nanoscale dimensions in materials lead to unique electronic and structural properties with applications ranging from site-specific drug delivery to anodes for lithium-ion batteries. These functional properties often involve large-amplitude strains and structural modifications, and thus require an understanding of the dynamics of these processes. Here we use femtosecond X-ray scattering techniques to visualize, in real time and with atomic-scale resolution, light-induced anisotropic strains in nanocrystal spheres and rods. Strains at the percent level are observed in CdS and CdSe samples, associated with a rapid expansion followed by contraction along the nanosphere or nanorod radial direction driven by a transient carrier-induced stress. These morphological changes occur simultaneously with the first steps in the melting transition on hundreds of femtosecond timescales. This work represents the first direct real-time probe of the dynamics of these large-amplitude strains and shape changes in few-nanometre-scale particles.

Ultrahigh-pressure polyamorphism in GeO2 glass with coordination number >6

NASA Astrophysics Data System (ADS)

Kono, Yoshio; Kenney-Benson, Curtis; Ikuta, Daijo; Shibazaki, Yuki; Wang, Yanbin; Shen, Guoyin

2016-03-01

Knowledge of pressure-induced structural changes in glasses is important in various scientific fields as well as in engineering and industry. However, polyamorphism in glasses under high pressure remains poorly understood because of experimental challenges. Here we report new experimental findings of ultrahigh-pressure polyamorphism in GeO2 glass, investigated using a newly developed double-stage large-volume cell. The Ge-O coordination number (CN) is found to remain constant at ∼6 between 22.6 and 37.9 GPa. At higher pressures, CN begins to increase rapidly and reaches 7.4 at 91.7 GPa. This transformation begins when the oxygen-packing fraction in GeO2 glass is close to the maximal dense-packing state (the Kepler conjecture = ∼0.74), which provides new insights into structural changes in network-forming glasses and liquids with CN higher than 6 at ultrahigh-pressure conditions.

Transformation of socio-cultural aspect of gated housing’s residence in Medan City, Indonesia.

NASA Astrophysics Data System (ADS)

Nirfalini Aulia, Dwira

2018-03-01

Gated Community Housing develops rapidly in Medan City and other big cities in Indonesia. These housing types initially reserved for middle to high-income residents. Transformation can describe as changes from one condition to another condition that can happen continuously in time. Change is affected by internal and external factors. Internal factors include culture, perspective, and social system while external factors include science progress and other cultural influence. This research is a descriptive study which tries to describe the phenomenon that is currently ongoing. Gated housing chosen are Perumahan Taman Setia Budi Indah, Perumahan Bumi Asri dan Perumahan Graha Helvetia. Characteristics of gated housing’s residents transform by the regional or national socioeconomic transformation. The structure and function of human social life are not uniform; meaning in every social life setting each of the structure and function are different. The characteristic of a community will transform in continuity.

Oxidation-induced structural changes in sub-nanometer platinum supported on alumina

DOE PAGES

DeBusk, Melanie Moses; Allard, Jr, Lawrence Frederick; Blom, Douglas Allen; ...

2015-06-26

Platinum supported on alumina is an essential component of emission treatment catalysts used in transportation. Theoretical, experimental, and mechanistic aspects of platinum particles supported on a variety of supports have been extensively studied; however, available experimental information on the behavior of single vs. sub-nanometer platinum is extremely limited. To bridge the knowledge gap between single supported platinum and well-formed supported platinum nanoparticles, we have carried out synthesis, characterization, and CO and NO oxidation studies of sub-nanometer platinum supported on α, θ, and γ-Al 2O 3 and monitored changes in structure upon exposure to CO and NO oxidation conditions. Furthermore, wemore » find that sub-nanometer Pt is highly effective for CO oxidation due to high platinum dispersion but is not very efficient as NO oxidation catalyst. Lastly, sub-nanometer platinum agglomerates rapidly under CO or NO oxidation conditions to form nanoparticles.« less

Fabrication of 3D photonic crystals from chitosan that are responsive to organic solvents.

PubMed

Huang, Guanbo; Yin, Yibing; Pan, Zeng; Chen, Mingxi; Zhang, Lei; Liu, Yu; Zhang, Yongli; Gao, Jianping

2014-12-08

Inspired by photonic nanostructures in nature, such as the hair-like chaetae on the body of sea mice, inverse opal photonic crystals films were fabricated with chitosan, a kind of biomacromolecule found in nature. First, monodispersed polystyrene (PS) colloidal crystal templates with different particle sizes were prepared. The inverse opal films (IOFs) were fabricated through in situ cross-linking of the PS templates. The IOFs contain periodically ordered interconnecting pores that endow the films with photonic stop bands and structural colors, which are visible to the naked eye. The IOFs exhibit rapid reversible changes in their structural colors and reflectance peaks in response to alcohols and phenols. Possible mechanisms for the shifts in the IOF's reflectance peaks are proposed. The changes in the IOFs in response to alcohols and phenols provide a potential way to visually detect these organic solvents.

Investigation of potent lead for acquired immunodeficiency syndrome from traditional Chinese medicine.

PubMed

Hung, Tzu-Chieh; Lee, Wen-Yuan; Chen, Kuen-Bao; Chan, Yueh-Chiu; Chen, Calvin Yu-Chian

2014-01-01

Acquired immunodeficiency syndrome (AIDS), caused by human immunodeficiency virus (HIV), has become, because of the rapid spread of the disease, a serious global problem and cannot be treated. Recent studies indicate that VIF is a protein of HIV to prevent all of human immunity to attack HIV. Molecular compounds of traditional Chinese medicine (TCM) database filtered through molecular docking and molecular dynamics simulations to inhibit VIF can protect against HIV. Glutamic acid, plantagoguanidinic acid, and Aurantiamide acetate based docking score higher with other TCM compounds selected. Molecular dynamics are useful for analysis and detection ligand interactions. According to the docking position, hydrophobic interactions, hydrogen bonding changes, and structure variation, the study try to select the efficacy of traditional Chinese medicine compound Aurantiamide acetate is better than the other for protein-ligand interactions to maintain the protein composition, based on changes in the structure.

Assessment of higher order structure comparability in therapeutic proteins using nuclear magnetic resonance spectroscopy.

PubMed

Amezcua, Carlos A; Szabo, Christina M

2013-06-01

In this work, we applied nuclear magnetic resonance (NMR) spectroscopy to rapidly assess higher order structure (HOS) comparability in protein samples. Using a variation of the NMR fingerprinting approach described by Panjwani et al. [2010. J Pharm Sci 99(8):3334-3342], three nonglycosylated proteins spanning a molecular weight range of 6.5-67 kDa were analyzed. A simple statistical method termed easy comparability of HOS by NMR (ECHOS-NMR) was developed. In this method, HOS similarity between two samples is measured via the correlation coefficient derived from linear regression analysis of binned NMR spectra. Applications of this method include HOS comparability assessment during new product development, manufacturing process changes, supplier changes, next-generation products, and the development of biosimilars to name just a few. We foresee ECHOS-NMR becoming a routine technique applied to comparability exercises used to complement data from other analytical techniques. Copyright © 2013 Wiley Periodicals, Inc.

Technology Transfer Center to Assume Patenting and Licensing Responsibilities | Poster

Cancer.gov

The NCI Technology Transfer Center (TTC) is undergoing a reorganization that will bring patenting and licensing responsibilities to the Shady Grove and Frederick offices by October 2015. The reorganization is a result of an effort begun in 2014 by NIH to improve the organizational structure of technology transfer at NIH to meet the rapid rate of change within science, technology, and industry, and to better align the science and laboratory goals with the licensing and patenting process.

Studying the orientation of bio-objects by nematic liquid crystals

NASA Astrophysics Data System (ADS)

Zubtsova, Yu. A.; Kamanin, A. A.; Kamanina, N. V.

2017-05-01

We have studied the ability of a liquid-crystal (LC) matrix to visualize and orient DNA molecules. It is established that the relief of the interface between the LC mesophase and conducting contact can be improved without using an additional high-ohmic polymer layer. Spectroscopic and ellipsometric techniques revealed changes in the refractive properties and structure of composites. The obtained results can be used in creating devices for rapid DNA testing with retained form of biostructures.

Cumulates, Dykes and Pressure Solution in the Ice-Salt Mantle of Europa: Geological Consequences of Pressure Dependent Liquid Compositions and Volume Changes During Ice-Salt Melting Reactions.

NASA Astrophysics Data System (ADS)

Day, S.; Asphaug, E.; Bruesch, L.

2002-12-01

Water-salt analogue experiments used to investigate cumulate processes in silicate magmas, along with observations of sea ice and ice shelf behaviour, indicate that crystal-melt separation in water-salt systems is a rapid and efficient process even on scales of millimetres and minutes. Squeezing-out of residual melts by matrix compaction is also predicted to be rapid on geological timescales. We predict that the ice-salt mantle of Europa is likely to be strongly stratified, with a layered structure predictable from density and phase relationships between ice polymorphs, aqueous saline solutions and crystalline salts such as hydrated magnesium sulphates (determined experimentally by, inter alia, Hogenboom et al). A surface layer of water ice flotation cumulate will be separated from denser salt cumulates by a cotectic horizon. This cotectic horizon will be both the site of subsequent lowest-temperature melting and a level of neutral buoyancy for the saline melts produced. Initial melting will be in a narrow depth range owing to increasing melting temperature with decreasing pressure: the phase relations argue against direct melt-though to the surface unless vesiculation occurs. Overpressuring of dense melts due to volume expansion on cotectic melting is predicted to lead to lateral dyke emplacement and extension above the dyke tips. Once the liquid leaves the cotectic, melting of water ice will involve negative volume change. Impact-generated melts will drain downwards through the fractured zones beneath crater floors. A feature in the complex crater Mannan'an, with elliptical ring fractures around a conical depression with a central pit, bears a close resemblance to Icelandic glacier collapse cauldrons produced by subglacial eruptions. Other structures resembling Icelandic cauldrons occur along Europan banded structures, while resurgence of ice rubble within collapse structures may produce certain types of chaos region. More general contraction of the ice mantle due to melting may be accommodated across banded structures by deformation and pressure solution. Expansion and contraction during different parts of a melting (and freezing) episode may account for the complexity of banded structures on Europa and inconsistent offsets of older structures across them.

Future automotive materials: Evolution or revolution

NASA Technical Reports Server (NTRS)

Beardmore, P.

1990-01-01

An exciting era is evolving in the application of new materials technologies to automotive applications. The desire on the part of the automobile industry to completely satisfy the customers while concurrently meeting increasing demands and regulations for stringent emission control and fuel efficiency is opening a plethora of opportunities for new materials. In many cases, materials solutions are the only mechanisms for resolving some of the upcoming issues. The materials scientist and engineer will therefore have a primary role to play and will assume a position of significance hithertofore unseen in the automobile industry. The nature of the industry dictates that changes are primarily evolutionary with respect to chronology but nevertheless some of the future material changes will be revolutionary in nature. This presentation will treat three primary systems of the vehicle separately, based on the different materials approaches which will be adopted. These areas are: (1) skin panels, (2) structures, and (3) powertrains. The competition between a variety of new materials in these 3 systems will be discussed in detail with the various tradeoffs being outlined. Amongst the more prominent of the new breed of materials will be new steel technologies, structural plastics (FRP), aluminum alloys (conventional and rapidly solidified), titanium alloys, metal matrix composites and smart materials (electrorheological fluids, etc.). The pace of development and application is accelerating rapidly and the impetus is likely to increase.

Local motion adaptation enhances the representation of spatial structure at EMD arrays

PubMed Central

Lindemann, Jens P.; Egelhaaf, Martin

2017-01-01

Neuronal representation and extraction of spatial information are essential for behavioral control. For flying insects, a plausible way to gain spatial information is to exploit distance-dependent optic flow that is generated during translational self-motion. Optic flow is computed by arrays of local motion detectors retinotopically arranged in the second neuropile layer of the insect visual system. These motion detectors have adaptive response characteristics, i.e. their responses to motion with a constant or only slowly changing velocity decrease, while their sensitivity to rapid velocity changes is maintained or even increases. We analyzed by a modeling approach how motion adaptation affects signal representation at the output of arrays of motion detectors during simulated flight in artificial and natural 3D environments. We focused on translational flight, because spatial information is only contained in the optic flow induced by translational locomotion. Indeed, flies, bees and other insects segregate their flight into relatively long intersaccadic translational flight sections interspersed with brief and rapid saccadic turns, presumably to maximize periods of translation (80% of the flight). With a novel adaptive model of the insect visual motion pathway we could show that the motion detector responses to background structures of cluttered environments are largely attenuated as a consequence of motion adaptation, while responses to foreground objects stay constant or even increase. This conclusion even holds under the dynamic flight conditions of insects. PMID:29281631

Polyethylene glycol promotes autoxidation of cytochrome c.

PubMed

Sato, Wataru; Uchida, Takeshi; Saio, Tomohide; Ishimori, Koichiro

2018-06-01

Cytochrome c (Cyt c) was rapidly oxidized by molecular oxygen in the presence, but not absence of PEG. The redox potential of heme c was determined by the potentiometric titration to be +236 ± 3 mV in the absence of PEG, which was negatively shifted to +200 ± 4 mV in the presence of PEG. The underlying the rapid oxidation was explored by examining the structural changes in Cyt c in the presence of PEG using UV-visible absorption, circular dichroism, resonance Raman, and fluorescence spectroscopies. These spectroscopic analyses suggested that heme oxidation was induced by a modest tertiary structural change accompanied by a slight shift in the heme position (<1.0 Å) rather than by partial denaturation, as is observed in the presence of cardiolipin. The near-infrared spectra showed that PEG induced dehydration from Cyt c, which triggered heme displacement. The primary dehydration site was estimated to be around surface-exposed hydrophobic residues near the heme center: Ile81 and Val83. These findings and our previous studies, which showed that hydrated water molecules around Ile81 and Val83 are expelled when Cyt c forms a complex with CcO, proposed that dehydration of these residues is functionally significant to electron transfer from Cyt c to CcO. Copyright © 2018 Elsevier B.V. All rights reserved.

Review of current status of smart structures and integrated systems

NASA Astrophysics Data System (ADS)

Chopra, Inderjit

1996-05-01

A smart structure involves distributed actuators and sensors, and one or more microprocessors that analyze the responses from the sensors and use distributed-parameter control theory to command the actuators to apply localized strains to minimize system response. A smart structure has the capability to respond to a changing external environment (such as loads or shape change) as well as to a changing internal environment (such as damage or failure). It incorporates smart actuators that allow the alteration of system characteristics (such as stiffness or damping) as well as of system response (such as strain or shape) in a controlled manner. Many types of actuators and sensors are being considered, such as piezoelectric materials, shape memory alloys, electrostrictive materials, magnetostrictive materials, electro- rheological fluids and fiber optics. These can be integrated with main load-carrying structures by surface bonding or embedding without causing any significant changes in the mass or structural stiffness of the system. Numerous applications of smart structures technology to various physical systems are evolving to actively control vibration, noise, aeroelastic stability, damping, shape and stress distribution. Applications range from space systems, fixed-wing and rotary-wing aircraft, automotive, civil structures and machine tools. Much of the early development of smart structures methodology was driven by space applications such as vibration and shape control of large flexible space structures, but now wider applications are envisaged for aeronautical and other systems. Embedded or surface-bonded smart actuators on an airplane wing or helicopter blade will induce alteration of twist/camber of airfoil (shape change), that in turn will cause variation of lift distribution and may help to control static and dynamic aeroelastic problems. Applications of smart structures technology to aerospace and other systems are expanding rapidly. Major barriers are: actuator stroke, reliable data base of smart material characteristics, non-availability of robust distributed parameter control strategies, and non-existent mathematical modeling of smart systems. The objective of this paper is to review the state-of-the-art of smart actuators and sensors and integrated systems and point out the needs for future research.

Phase transformation in rapidly quenched Fe-Cr-Co-Mo-Ti-Si-B alloys

NASA Astrophysics Data System (ADS)

Zhukov, D. G.; Shubakov, V. S.; Zhukova, E. Kh; Gorshenkov, M. V.

2018-03-01

The research results of phase transformations in Fe-24Cr-16Co-3Mo-0.2Ti-1Si-B alloys (with a boron content of 1 to 3% by mass) obtained by rapid quenching are presented. The structure formation regularities during the melt spinning and during the subsequent crystallization annealing in rapidly quenched bands of the Fe-Cr-Co-Mo-Ti-Si-B system alloys were studied. The changes in the phase composition of the rapidly quenched Fe-Cr-Co-Mo-Ti- Si-B system alloys after quenching at various quench rates and at different boron concentrations in the alloys are studied. It is shown that during crystallization from an amorphous state, at temperatures above 570 °C, in addition to the α-phase, the σ-phase appears first, followed by the γ-phase. Heat treatment of rapidly quenched bands to high-coercive state was carried out. A qualitative assessment of magnetic properties in a high-coercivity state was carried out. An evaluation of the level of magnetic properties in a high-coercivity state allows us to conclude that the application of a magnetic field during crystallization from an amorphous state leads to anisotropy of the magnetic properties, that is, an anisotropic effect of thermo-magnetic treatment is detected.

Rapid Assessment of Aircraft Structural Topologies for Multidisciplinary Optimization and Weight Estimation

NASA Technical Reports Server (NTRS)

Samareh, Jamshid A.; Sensmeier, mark D.; Stewart, Bret A.

2006-01-01

Algorithms for rapid generation of moderate-fidelity structural finite element models of air vehicle structures to allow more accurate weight estimation earlier in the vehicle design process have been developed. Application of these algorithms should help to rapidly assess many structural layouts before the start of the preliminary design phase and eliminate weight penalties imposed when actual structure weights exceed those estimated during conceptual design. By defining the structural topology in a fully parametric manner, the structure can be mapped to arbitrary vehicle configurations being considered during conceptual design optimization. Recent enhancements to this approach include the porting of the algorithms to a platform-independent software language Python, and modifications to specifically consider morphing aircraft-type configurations. Two sample cases which illustrate these recent developments are presented.

Differential progression of structural and functional alterations in distinct retinal ganglion cell types in a mouse model of glaucoma.

PubMed

Della Santina, Luca; Inman, Denise M; Lupien, Caroline B; Horner, Philip J; Wong, Rachel O L

2013-10-30

Intraocular pressure (IOP) elevation is a principal risk factor for glaucoma. Using a microbead injection technique to chronically raise IOP for 15 or 30 d in mice, we identified the early changes in visual response properties of different types of retinal ganglion cells (RGCs) and correlated these changes with neuronal morphology before cell death. Microbead-injected eyes showed reduced optokinetic tracking as well as cell death. In such eyes, multielectrode array recordings revealed that four RGC types show diverse alterations in their light responses upon IOP elevation. OFF-transient RGCs exhibited a more rapid decline in both structural and functional organizations compared with other RGCs. In contrast, although the light-evoked responses of OFF-sustained RGCs were perturbed, the dendritic arbor of this cell type remained intact. ON-transient and ON-sustained RGCs had normal functional receptive field sizes but their spontaneous and light-evoked firing rates were reduced. ON- and OFF-sustained RGCs lost excitatory synapses across an otherwise structurally normal dendritic arbor. Together, our observations indicate that there are changes in spontaneous activity and light-evoked responses in RGCs before detectable dendritic loss. However, when dendrites retract, we found corresponding changes in receptive field center size. Importantly, the effects of IOP elevation are not uniformly manifested in the structure and function of diverse RGC populations, nor are distinct RGC types perturbed within the same time-frame by such a challenge.

Inhibition of trihalomethane formation in city water by radiation-ozone treatment and rapid composting of radiation disinfected sewage sludge

NASA Astrophysics Data System (ADS)

Takehisa, M.; Arai, H.; Arai, M.; Miyata, T.; Sakumoto, A.; Hashimoto, S.; Nishimura, K.; Watanabe, H.; Kawakami, W.; Kuriyama, I.

Humic acid and Fulvic acid in natural water are precursors of carcinogenic THM which is formed during chlorine disinfection in city water processing. The radiation-oxidation process in the presence of ozone is effective to remove the precursors. The THM formation was reduced more than the decrease in TOC by the combination treatment. This is mainly due to a change in the chemical structure of the oxidation products. A composting of radiation disinfected sludge cake for agricultural reuse could be achieved within 3 days primary fermentation in a sewage plant. The rapid fermentation with use of radiation is effective to scale down of a fermentor of composting plant and the process reduces a health risk from the workers as well as final users.