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Showing papers by "Iowa State University published in 2004"


Journal ArticleDOI
TL;DR: A survey of state-of-the-art routing techniques in WSNs is presented and the design trade-offs between energy and communication overhead savings in every routing paradigm are studied.
Abstract: Wireless sensor networks consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specifically designed for WSNs where energy awareness is an essential design issue. Routing protocols in WSNs might differ depending on the application and network architecture. In this article we present a survey of state-of-the-art routing techniques in WSNs. We first outline the design challenges for routing protocols in WSNs followed by a comprehensive survey of routing techniques. Overall, the routing techniques are classified into three categories based on the underlying network structure: flit, hierarchical, and location-based routing. Furthermore, these protocols can be classified into multipath-based, query-based, negotiation-based, QoS-based, and coherent-based depending on the protocol operation. We study the design trade-offs between energy and communication overhead savings in every routing paradigm. We also highlight the advantages and performance issues of each routing technique. The article concludes with possible future research areas.

4,701 citations


Journal ArticleDOI
Midori A. Harris, Jennifer I. Clark1, Ireland A1, Jane Lomax1, Michael Ashburner2, Michael Ashburner1, R. Foulger1, R. Foulger2, Karen Eilbeck1, Karen Eilbeck3, Suzanna E. Lewis3, Suzanna E. Lewis1, B. Marshall3, B. Marshall1, Christopher J. Mungall1, Christopher J. Mungall3, J. Richter1, J. Richter3, Gerald M. Rubin1, Gerald M. Rubin3, Judith A. Blake1, Carol J. Bult1, Dolan M1, Drabkin H1, Janan T. Eppig1, Hill Dp1, L. Ni1, Ringwald M1, Rama Balakrishnan4, Rama Balakrishnan1, J. M. Cherry4, J. M. Cherry1, Karen R. Christie4, Karen R. Christie1, Maria C. Costanzo1, Maria C. Costanzo4, Selina S. Dwight4, Selina S. Dwight1, Stacia R. Engel4, Stacia R. Engel1, Dianna G. Fisk1, Dianna G. Fisk4, Jodi E. Hirschman1, Jodi E. Hirschman4, Eurie L. Hong1, Eurie L. Hong4, Robert S. Nash4, Robert S. Nash1, Anand Sethuraman4, Anand Sethuraman1, Chandra L. Theesfeld4, Chandra L. Theesfeld1, David Botstein1, David Botstein5, Kara Dolinski1, Kara Dolinski5, Becket Feierbach5, Becket Feierbach1, Tanya Z. Berardini1, Tanya Z. Berardini6, S. Mundodi1, S. Mundodi6, Seung Y. Rhee1, Seung Y. Rhee6, Rolf Apweiler1, Daniel Barrell1, Camon E1, E. Dimmer1, Lee1, Rex L. Chisholm, Pascale Gaudet7, Pascale Gaudet1, Warren A. Kibbe1, Warren A. Kibbe7, Ranjana Kishore1, Ranjana Kishore8, Erich M. Schwarz1, Erich M. Schwarz8, Paul W. Sternberg1, Paul W. Sternberg8, M. Gwinn1, Hannick L1, Wortman J1, Matthew Berriman1, Matthew Berriman9, Wood9, Wood1, de la Cruz N1, de la Cruz N10, Peter J. Tonellato1, Peter J. Tonellato10, Pankaj Jaiswal11, Pankaj Jaiswal1, Seigfried T12, Seigfried T1, White R13, White R1 
TL;DR: The Gene Ontology (GO) project as discussed by the authors provides structured, controlled vocabularies and classifications that cover several domains of molecular and cellular biology and are freely available for community use in the annotation of genes, gene products and sequences.
Abstract: The Gene Ontology (GO) project (http://www.geneontology.org/) provides structured, controlled vocabularies and classifications that cover several domains of molecular and cellular biology and are freely available for community use in the annotation of genes, gene products and sequences. Many model organism databases and genome annotation groups use the GO and contribute their annotation sets to the GO resource. The GO database integrates the vocabularies and contributed annotations and provides full access to this information in several formats. Members of the GO Consortium continually work collectively, involving outside experts as needed, to expand and update the GO vocabularies. The GO Web resource also provides access to extensive documentation about the GO project and links to applications that use GO data for functional analyses.

3,565 citations


Journal ArticleDOI
TL;DR: This paper briefly update the discussion in that paper and summarize the advances in the ten years since the paper by Rohlf and Marcus (1993) and speculate on future directions in morphometric analysis.
Abstract: The analysis of shape is a fundamental part of much biological research. As the field of statistics developed, so have the sophistication of the analysis of these types of data. This lead to multivariate morphometrics in which suites of measurements were analyzed together using canonical variates analysis, principal components analysis, and related methods. In the 1980s, a fundamental change began in the nature of the data gathered and analyzed. This change focused on the coordinates of landmarks and the geometric information about their relative positions. As a by-product of such an approach, results of multivariate analyses could be visualized as configurations of landmarks back in the original space of the organism rather than only as statistical scatter plots. This new approach, called “geometric morphometrics”, had benefits that lead Rohlf and Marcus (1993) to proclaim a “revolution” in morphometrics. In this paper, we briefly update the discussion in that paper and summarize the advances in the ten years since the paper by Rohlf and Marcus. We also speculate on future directions in morphometric analysis.

1,910 citations


Journal ArticleDOI
TL;DR: It is reported that emergent factors such as disconfirmation and satisfaction are critical to understanding changes in IT users' beliefs and attitudes and recommend that they be included in future process models of IT usage.
Abstract: User beliefs and attitudes are key perceptions driving information technology usage. These perceptions, however, may change with time as users gain first-hand experience with IT usage, which, in turn, may change their subsequent IT usage behavior. This paper elaborates how users' be liefs and attitudes change during the course of their IT usage, defines emergent constructs driving such change, and proposes a temporal model of belief and attitude change by drawing on expectation-disconfirmation theory and the extant IT usage literature. Student data from two longitudinal studies in end-user computing (computer-based training system usage) and system development (rapid application development software usage) contexts provided empirical support for the hypothesized model, demonstrated its generalizability across technologies and usage contexts, and allowed us to probe context-specific differences. Content analysis of qualitative data validated some of our quantitative results. We report that emergent factors such as disconfirmation and satisfaction are critical to understanding changes in IT users' beliefs and attitudes and recommend that they be included in future process models of IT usage.

1,632 citations


Journal ArticleDOI
19 Nov 2004-Science
TL;DR: The measured optical spectra of the nanofabricated gold structures come very close to the theoretical expectations and additional numerical simulations show that the structures exhibit a frequency range with negative permeability for a beam configuration in which the magnetic field couples to the LC resonance.
Abstract: An array of single nonmagnetic metallic split rings can be used to implement a magnetic resonance, which arises from an inductor-capacitor circuit (LC) resonance, at 100-terahertz frequency. The excitation of the LC resonance in the normal-incidence geometry used in our experiments occurs through the coupling of the electric field of the incident light to the capacitance. The measured optical spectra of the nanofabricated gold structures come very close to the theoretical expectations. Additional numerical simulations show that our structures exhibit a frequency range with negative permeability for a beam configuration in which the magnetic field couples to the LC resonance. Together with an electric response that has negative permittivity, this can lead to materials with a negative index of refraction.

1,448 citations


Journal ArticleDOI
01 Nov 2004-Polymer
TL;DR: In this article, a poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film is enhanced by more than 100 fold on adding some organic compounds into aqueous solutions or by treating it with organic solvents, such as ethylene glycol, 2-nitroethanol, methyl sulfoxide or 1-methyl-2-pyrrolidinone.

1,198 citations


Journal ArticleDOI
TL;DR: The fabrication—through direct laser writing—and detailed characterization of high-quality large-scale f.c. c.
Abstract: The past decade has witnessed intensive research efforts related to the design and fabrication of photonic crystals1,2. These periodically structured dielectric materials can represent the optical analogue of semiconductor crystals, and provide a novel platform for the realization of integrated photonics. Despite intensive efforts, inexpensive fabrication techniques for large-scale three-dimensional photonic crystals of high enough quality, with photonic bandgaps at near-infrared frequencies, and built-in functional elements for telecommunication applications, have been elusive. Direct laser writing by multiphoton polymerization3 of a photoresist has emerged as a technique for the rapid, cheap and flexible fabrication of nanostructures for photonics. In 1999, so-called layer-by-layer4 or woodpile photonic crystals were fabricated with a fundamental stop band at 3.9 μm wavelength5. In 2002, a corresponding 1.9 μm was achieved6, but the important face-centred-cubic (f.c.c.) symmetry was abandoned. Importantly, fundamental stop bands or photonic bandgaps at telecommunication wavelengths have not been demonstrated. In this letter, we report the fabrication—through direct laser writing—and detailed characterization of high-quality large-scale f.c.c. layer-by-layer structures, with fundamental stop bands ranging from 1.3 to 1.7 μm.

1,054 citations


Journal ArticleDOI
TL;DR: This paper investigated the use of multi-word sequences in two important university registers: classroom teaching and textbooks and found that lexical bundles are usually not complete grammatical structures nor are they idiomatic, but they function as basic building blocks of discourse.
Abstract: This paper investigates the use of multi-word sequences in two important university registers: classroom teaching and textbooks. Following Biber et al. (1999), we take a frequency-driven approach to the identification of multi-word sequences, referred to as 'lexical bundles'. We compare the lexical bundles in classroom teaching and textbooks to those found in our previous research on conversation and academic prose. Structural patterns are described first, and then we present a functional taxonomy, including stance expressions, discourse organizers, and referential expressions. The use of lexical bundles in classroom teaching turns out to be especially surprising, both in frequency and in function. Classroom teaching uses more stance and discourse organizing bundles than conversation does, but at the same time, classroom teaching uses more referential bundles than academic prose. The analysis indicates that lexical bundles - the most frequent sequences of words in a register - are a unique linguistic construct. Lexical bundles are usually not complete grammatical structures nor are they idiomatic, but they function as basic building blocks of discourse. In the conclusion, we discuss the implications of our study for the theoretical status of lexical bundles.

1,033 citations


Journal ArticleDOI
TL;DR: Progress has been made in elucidating the molecular, biochemical, chemical and genetic bases of magnetosome formation and understanding how these unique intracellular organelles function.
Abstract: Magnetotactic bacteria were discovered almost 30 years ago, and for many years and many different reasons, the number of researchers working in this field was few and progress was slow. Recently, however, thanks to the isolation of new strains and the development of new techniques for manipulating these strains, researchers from several laboratories have made significant progress in elucidating the molecular, biochemical, chemical and genetic bases of magnetosome formation and understanding how these unique intracellular organelles function. We focus here on this progress.

1,009 citations



Journal ArticleDOI
TL;DR: Clusters of SSR markers from map-referenced BAC clones was a very effective means of targeting markers to marker-scarce positions in the genome, indicating the significant association of genes and SSRs.
Abstract: A total of 391 simple sequence repeat (SSR) markers designed from genomic DNA libraries, 24 derived from existing GenBank genes or ESTs, and five derived from bacterial artificial chromosome (BAC) end sequences were developed. In contrast to SSRs derived from EST sequences, those derived from genomic libraries were a superior source of polymorphic markers, given that the mean number of tandem repeats in the former was significantly less than that of the latter (P<0.01). The 420 newly developed SSRs were mapped in one or more of five soybean mapping populations: ‘Minsoy’ × ‘Noir 1’, ‘Minsoy’ × ‘Archer’, ‘Archer’ × ‘Noir 1’, ‘Clark’ × ‘Harosoy’, and A81-356022 × PI468916. The JoinMap software package was used to combine the five maps into an integrated genetic map spanning 2,523.6 cM of Kosambi map distance across 20 linkage groups that contained 1,849 markers, including 1,015 SSRs, 709 RFLPs, 73 RAPDs, 24 classical traits, six AFLPs, ten isozymes, and 12 others. The number of new SSR markers added to each linkage group ranged from 12 to 29. In the integrated map, the ratio of SSR marker number to linkage group map distance did not differ among 18 of the 20 linkage groups; however, the SSRs were not uniformly spaced over a linkage group, clusters of SSRs with very limited recombination were frequently present. These clusters of SSRs may be indicative of gene-rich regions of soybean, as has been suggested by a number of recent studies, indicating the significant association of genes and SSRs. Development of SSR markers from map-referenced BAC clones was a very effective means of targeting markers to marker-scarce positions in the genome.

Journal ArticleDOI
TL;DR: The Psychological Entitlement Scale was found to be reliable and valid, not associated with social desirability, stable across time, and correlated negatively with two of the Big Five factors: agreeableness and emotional stability.
Abstract: Nine studies were conducted with the goal of developing a self-report measure of psychological entitlement and assessing its interpersonal consequences. The Psychological Entitlement Scale (PES) was found to be reliable and valid (Study 1, 2), not associated with social desirability (Study 2), stable across time (Study 3), and correlated negatively with two of the Big Five factors: agreeableness and emotional stability (Study 4). The validity of the PES was confirmed in studies that assessed willingness to take candy designated for children (Study 5) and reported deservingness of pay in a hypothetical employment setting (Study 6). Finally, the PES was linked to important interpersonal consequences including competitive choices in a commons dilemma (Study 7), selfish approaches to romantic relationships (Study 8), and aggression following ego threat (Study 9). Psychological entitlement has a pervasive and largely unconstructive impact on social behavior.

Journal ArticleDOI
TL;DR: The G2-PAMAM-capped MSN material (G2-MSN) was used to complex with a plasmid DNA (pEGFP-C1) that encodes for an enhanced green fluorescence protein that renders the possibility to serve as a universal transmembrane carrier for intracellular drug delivery and imaging applications.
Abstract: We synthesized a MCM-41-type mesoporous silica nanosphere (MSN)-based gene transfection system, where second generation (G2) polyamidoamines (PAMAMs) were covalently attached to the surface of MSN The G2-PAMAM-capped MSN material (G2-MSN) was used to complex with a plasmid DNA (pEGFP-C1) that encodes for an enhanced green fluorescence protein The gene transfection efficacy, uptake mechanism, and biocompatibility of the G2-MSN system with various cell types, such as neural glia (astrocytes), human cervical cancer (HeLa), and Chinese hamster ovarian (CHO) cells, were investigated The mesoporous structure of the MSN material allows membrane-impermeable molecules, such as pharmaceutical drugs and fluorescent dyes, to be encapsulated inside the MSN channels The system renders the possibility to serve as a universal transmembrane carrier for intracellular drug delivery and imaging applications

Journal ArticleDOI
TL;DR: This work proposes community-based efforts to define common criteria and to initiate concerted actions directed towards the release of standard reference materials, construction of consolidated metabolite libraries, and development of metabolite-specific data-management systems.

Journal ArticleDOI
TL;DR: A standardized kinesin nomenclature based on 14 family designations is set forth, which unifies all previous phylogenies and nomenClature proposals, while allowing individual sequence names to remain the same, and for expansion to occur as new sequences are discovered.
Abstract: In recent years the kinesin superfamily has become so large that several different naming schemes have emerged, leading to confusion and miscommunication. Here, we set forth a standardized kinesin nomenclature based on 14 family designations. The scheme unifies all previous phylogenies and nomenclature proposals, while allowing individual sequence names to remain the same, and for expansion to occur as new sequences are discovered.

Journal ArticleDOI
TL;DR: Preventing fatty liver by supplying cows with sufficient nutrients and a clean and health-promoting environment in the peripartal period would reduce production losses of cows more than would any treatment of fatty liver.

Journal ArticleDOI
TL;DR: In this article, the authors compare individual equity return data from Thomson Datastream (TDS) for one large national equity market, the United States, to the source most often used by academics, the Center for Research in Security Prices (CRSP), for the period 1975-2002.
Abstract: We compare individual equity return data from Thomson Datastream (TDS) for one large national equity market, the United States, to the source most often used by academics, the Center for Research in Security Prices (CRSP) for the period 1975-2002. Our purpose is not to advocate for the use of a particular source of U.S. equity data but to evaluate the suitability of TDS for use in studies involving large numbers of individual equities in markets outside the U.S. We discover important issues of coverage, classification, and data integrity and find that naive use of TDS data can have a large impact on economic inferences, particularly earlier in the period of coverage and among smaller stocks. We show that after careful screening of the TDS data that although differences still remain, inferences drawn from TDS data are similar to those drawn from CRSP. We also apply our screens to a sample of four European equity markets and show that screening the data has a measurable impact on the time series of country portfolio returns.

Journal ArticleDOI
TL;DR: Although molecular genetic information has been used in industry programs for several decades and is growing, the extent of use has not lived up to initial expectations and the current attitude toward marker-assisted selection is therefore one of cautious optimism.
Abstract: During the past few decades, advances in molecular genetics have led to the identification of multiple genes or genetic markers associated with genes that affect traits of interest in livestock, including genes for single-gene traits and QTL or genomic regions that affect quantitative traits. This has provided opportunities to enhance response to selection, in particular for traits that are difficult to improve by conventional selection (low heritability or traits for which measurement of phenotype is difficult, expensive, only possible late in life, or not possible on selection candidates). Examples of genetic tests that are available to or used in industry programs are documented and classified into causative mutations (direct markers), linked markers in population-wide linkage disequilibrium with the QTL (LD markers), and linked markers in population-wide equilibrium with the QTL (LE markers). In general, although molecular genetic information has been used in industry programs for several decades and is growing, the extent of use has not lived up to initial expectations. Most applications to date have been integrated in existing programs on an ad hoc basis. Direct markers are preferred for effective implementation of marker-assisted selection, followed by LD and LE markers, the latter requiring within-family analysis and selection. Ease of application and potential for extra-genetic gain is greatest for direct markers, followed by LD markers, but is antagonistic to ease of detection, which is greatest for LE markers. Although the success of these applications is difficult to assess, several have been hampered by logistical requirements, which are substantial, in particular for LE markers. Opportunities for the use of molecular information exist, but their successful implementation requires a comprehensive integrated strategy that is closely aligned with business goals. The current attitude toward marker-assisted selection is therefore one of cautious optimism.

Journal ArticleDOI
TL;DR: An updated meta-analysis reveals that exposure to violent video games is significantly linked to increases in aggressive behaviour, aggressive cognition, aggressive affect, and cardiovascular arousal, and to decreases in helping behaviour.

Journal ArticleDOI
S. S. Adler1, S. Afanasiev2, Christine Angela Aidala1, N. N. Ajitanand3  +337 moreInstitutions (41)
TL;DR: In this paper, the authors measured the centrality dependence of transverse momentum distributions and particle yields at the PHENIX experiment at the Relativistic Heavy Ion Collider (HIC).
Abstract: The centrality dependence of transverse momentum distributions and yields for ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}},{K}^{\ifmmode\pm\else\textpm\fi{}},p$, and $\overline{p}$ in $\text{Au}+\text{Au}$ collisions at $\sqrt{{s}_{NN}}=200\phantom{\rule{0.3em}{0ex}}\text{GeV}$ at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider. We observe a clear particle mass dependence of the shapes of transverse momentum spectra in central collisions below $\ensuremath{\sim}2\phantom{\rule{0.3em}{0ex}}\text{GeV}∕c$ in ${p}_{T}$. Both mean transverse momenta and particle yields per participant pair increase from peripheral to midcentral and saturate at the most central collisions for all particle species. We also measure particle ratios of ${\ensuremath{\pi}}^{\ensuremath{-}}∕{\ensuremath{\pi}}^{+}$, ${K}^{\ensuremath{-}}∕{K}^{+}$, $\overline{p}∕p$, $K∕\ensuremath{\pi}$, $p∕\ensuremath{\pi}$, and $\overline{p}∕\ensuremath{\pi}$ as a function of ${p}_{T}$ and collision centrality. The ratios of equal mass particle yields are independent of ${p}_{T}$ and centrality within the experimental uncertainties. In central collisions at intermediate transverse momenta $\ensuremath{\sim}1.5--4.5\phantom{\rule{0.3em}{0ex}}\text{GeV}∕c$, proton and antiproton yields constitute a significant fraction of the charged hadron production and show a scaling behavior different from that of pions.

Journal ArticleDOI
TL;DR: Pearly mussel research has begun to benefit from and contribute to current ideas about suspension feeding, life-history theory, metapopulations, flow refuges, spatial patterning and its effects, and management of endangered species.
Abstract: Pearly mussels (Unionacea) are widespread, abundant, and important in freshwater ecosystems around the world. Catastrophic declines in pearly mussel populations in North America and other parts of the world have led to a flurry of research on mussel biology, ecology, and conservation. Recent research on mussel feeding, life history, spatial patterning, and declines has augmented, modified, or overturned long-held ideas about the ecology of these animals. Pearly mussel research has begun to benefit from and contribute to current ideas about suspension feeding, life-history theory, metapopulations, flow refuges, spatial patterning and its effects, and management of endangered species. At the same time, significant gaps in understanding and apparent paradoxes in pearly mussel ecology have been exposed. To conserve remaining mussel populations, scientists and managers must simultaneously and aggressively pursue both rigorous research and conservation actions.

Journal ArticleDOI
TL;DR: This paper investigated the use of lexical bundles, a special type of word combination, defined as a sequence of three or more words that co-occur frequently in a particular register.

Journal ArticleDOI
TL;DR: In this article, an overview of the current state of the research field of adaptive and environmentally sensitive polymer surfaces designed to respond to external stimuli in a controlled and predictable manner is presented.

Journal ArticleDOI
Felix Aharonian1, A. G. Akhperjanian2, Klaus-Michael Aye3, A. R. Bazer-Bachi4, M. Beilicke5, Wystan Benbow1, David Berge1, P. Berghaus6, P. Berghaus7, Konrad Bernlöhr1, Konrad Bernlöhr8, O. Bolz1, Catherine Boisson4, C. Borgmeier8, F. Breitling8, A. M. Brown3, J. Bussons Gordo9, P. M. Chadwick3, V. R. Chitnis4, V. R. Chitnis10, L-M. Chounet11, R. Cornils5, Luigi Costamante1, B. Degrange11, A. Djannati-Ataï7, L. O'c. Drury12, Tulun Ergin8, P. Espigat7, F. Feinstein9, P. Fleury11, G. Fontaine11, Stefan Funk1, Y. A. Gallant9, B. Giebels11, Stefan Gillessen1, P. Goret13, Julien Guy6, Julien Guy4, C. Hadjichristidis3, M. Hauser, G. Heinzelmann5, Gilles Henri14, German Hermann1, Jim Hinton1, Werner Hofmann1, M. Holleran15, Dieter Horns1, O. C. de Jager15, I. Jung16, I. Jung1, B. Khélifi1, Nu. Komin8, A. Konopelko8, A. Konopelko1, I. J. Latham3, R. Le Gallou3, M. Lemoine11, A. Lemière7, N. Leroy11, Thomas Lohse8, A. Marcowith4, Conor Masterson1, T. J. L. McComb3, M. de Naurois6, M. de Naurois4, S. J. Nolan3, A. Noutsos3, K. J. Orford3, J. L. Osborne3, M. Ouchrif6, M. Ouchrif4, M. Panter1, Guy Pelletier14, S. Pita7, Martin Pohl17, Martin Pohl18, G. Pühlhofer1, Michael Punch7, B. C. Raubenheimer15, M. Raue5, J. Raux6, J. Raux4, S. M. Rayner3, I. Redondo19, I. Redondo11, A. Reimer17, Olaf Reimer17, J. Ripken5, M. Rivoal4, M. Rivoal6, L. Rob20, L. Rolland4, L. Rolland6, Gavin Rowell1, V. Sahakian2, L. Saugé14, S. Schlenker8, Reinhard Schlickeiser17, C. Schuster17, U. Schwanke8, M. Siewert17, Helene Sol4, R. Steenkamp21, C. Stegmann8, J.-P. Tavernet6, J.-P. Tavernet4, C. G. Théoret7, M. Tluczykont11, D. J. van der Walt15, G. Vasileiadis9, P. Vincent6, P. Vincent4, B. Visser15, Heinrich J. Völk1, Stefan Wagner 
04 Nov 2004-Nature
TL;DR: A TeV γ-ray image of the SNR shows the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there, consistent with current ideas of particle acceleration in young SNR shocks.
Abstract: A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays)1. The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically2,3, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7 - 3946 (G347.3 - 0.5), which was discovered by ROSAT4 in the X-ray spectrum and later claimed as a source of high-energy γ-rays5,6 of TeV energies (1 TeV = 1012 eV). We present a TeV γ-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.

Journal ArticleDOI
TL;DR: The relation between perceived racial discrimination and substance use was examined in a panel of 684 African American families, using the prototype-willingness model of adolescent health risk and effective parenting was associated with less willingness and intention to use.
Abstract: The relation between perceived racial discrimination and substance use was examined in a panel of 684 African American families, using the prototype-willingness model of adolescent health risk (F. X. Gibbons, M. Gerrard, & D. Lane, 2003). Discrimination was concurrently and prospectively related to use in the parents and the children (mean age = 10.5 years at Wave 1). The discrimination → use relation in the parents was mediated by distress (anxiety and depression). Among the children, the relation was mediated by distress as well as their risk cognitions (favorability of their risk images and their willingness to use) and the extent to which they reported affiliating with friends who were using substances. Each of these relations with discrimination was positive. In contrast, effective parenting was associated with less willingness and intention to use. Theoretical and applied implications of the results are discussed.

Journal ArticleDOI
TL;DR: An innovative fabrication of compliant nanocomposite membranes with nanoscale thickness showing extraordinary sensitivity and dynamic range is reported on, which makes them candidates for a new generation of membrane-based sensor arrays.
Abstract: Highly sensitive sensor arrays are in high demand for prospective applications in remote sensing and imaging. Measuring microscopic deflections of compliant micromembranes and cantilevers is developing into one of the most versatile approaches for thermal, acoustic and chemical sensing. Here, we report on an innovative fabrication of compliant nanocomposite membranes with nanoscale thickness showing extraordinary sensitivity and dynamic range, which makes them candidates for a new generation of membrane-based sensor arrays. These nanomembranes with a thickness of 25–70 nm, which can be freely suspended over large (hundred micrometres) openings are fabricated with molecular precision by time-efficient, spin-assisted layer-by-layer assembly. They are designed as multilayered molecular composites made of a combination of polymeric monolayers and a metal nanoparticle intralayer. We demonstrate that these nanocomposite membranes possess unparalleled sensitivity and a unique autorecovering ability. The membrane nanostructure that is responsible for these outstanding properties combines multilayered polymer/nanoparticle organization, high polymer-chain orientation, and a pre-stretched state.

Journal ArticleDOI
TL;DR: The results indicated that the antioxidantActivity of CP extracts was significantly affected by heating temperature and duration of treatment on CP and that the heating process can be used as a tool for increasing the antioxidant activity of CP.
Abstract: The effect of heat treatment on the antioxidant activity of extracts from Citrus unshiu peels was evaluated. Citrus peels (CP) (5 g) were placed in Pyrex Petri dishes (8.0 cm diameter) and heat-treated at 50, 100, or 150 °C for 10, 20, 30, 40, 50, and 60 min in an electric muffle furnace. After heat treatment, 70% ethanol extract (EE) and water extract (WE) (0.1 g/10 mL) of CP were prepared, and total phenol contents (TPC), radical scavenging activity (RSA), and reducing power of the extracts were determined. The antioxidant activities of CP extracts increased as heating temperature increased. For example, heat treatment of CP at 150 °C for 60 min increased the TPC, RSA, and reducing power of EE from 71.8 to 171.0 μM, from 29.64 to 64.25%, and from 0.45 to 0.82, respectively, compared to non-heat-treated control. In the case of WE from CP heat-treated at the same conditions (150 °C for 60 min), the TPC, RSA, and reducing power also increased from 84.4 to 204.9 μM, from 15.81 to 58.26%, and from 0.27 to 0....

Journal ArticleDOI
TL;DR: Biological maturity status significantly influences the functional capacity of adolescent football players 13–15 years of age, whereas training is a significant contributor to aerobic resistance, whereas weight and height are significant contributors to the sprint and vertical jump, respectively.
Abstract: The objective was to estimate the contribution of experience, body size and maturity status to variation in the functional capacities of adolescent football (soccer) players. The sample included 69 players 13.2-15.1 years of age from three clubs which competed in the highest division for their age group in the first Portuguese national division. Height and weight were measured and stage of pubic hair development was assessed at clinical examination. The number of years of experience in football was obtained at interview. Three tests of functional capacity were administered: 30-m dash (running speed), vertical jump (explosive power) and a yo-yo intermittent endurance test (aerobic resistance). Multiple linear regression analysis was used to estimate the relative contributions of age, stage of sexual maturity, height, weight and years of formal training in football to the three indicators of functional capacity. Stage of puberty, body size and years of training accounted for 21% to 50% of the variance in the three tasks. Sexual maturity status was the primary contributor to the variance in the intermittent shuttle run, whereas weight and height were the primary contributors to the explained variance in the 30-m dash and vertical jump, respectively. In conclusion, biological maturity status significantly influences the functional capacity of adolescent football players 13-15 years of age. Training is a significant contributor to aerobic resistance, whereas weight and height are significant contributors to the sprint and vertical jump, respectively.

Journal ArticleDOI
TL;DR: In this article, the effects of various levels and sequences of acceptance and rejection on emotion, ratings of self and others, and behavior were examined, showing that rejection elicited greater anger, sadness, and hurt feelings than acceptance, as well as an increased tendency to aggress toward the rejector.

Journal Article
TL;DR: The CSA/MTI appeared to have acceptable reliability for most research applications and values with the other devices indicate some possible concerns with reliability, but additional work is needed to better understand factors contributing to variability in accelerometry data.
Abstract: Introduction Numerous studies have examined the validity of accelerometry-based activity monitors but few studies have systematically studied the reliability of different accelerometer units for assessing a standardized bout of physical activity. Improving understanding of error in these devices is an important research objective because they are increasingly being used in large surveillance studies and intervention trials that require the use of multiple units over time. Methods Four samples of college-aged participants were recruited to collect reliability data on four different accelerometer types (CSA/MTI, Biotrainer Pro, Tritrac-R3D, and Actical). The participants completed three trials of treadmill walking (3 mph) while wearing multiple units of a specific monitor type. For each trial, the participant completed a series of 5-min bouts of walking (one for each monitoring unit) with 1-min of standing rest between each bout. Generalizability (G) theory was used to quantify variance components associated with individual monitor units, trials, and subjects as well as interactions between these terms. Results The overall G coefficients range from 0.43 to 0.64 for the four monitor types. Corresponding intraclass correlation coefficients (ICC) ranged from 0.62 to 0.80. The CSA/MTI was found to have the least variability across monitor units and trials and the highest overall reliability. The Actical was found to have the poorest reliability. Conclusion The CSA/MTI appeared to have acceptable reliability for most research applications (G values above 0.60 and ICC values above 0.80), but values with the other devices indicate some possible concerns with reliability. Additional work is needed to better understand factors contributing to variability in accelerometry data and to determine appropriate calibration protocols to improve reliability of these measures for different research applications.