Showing papers by "Florida State University published in 2004"

The metacommunity concept: a framework for multi-scale community ecology

Abstract: The metacommunity concept is an important way to think about linkages between different spatial scales in ecology. Here we review current understanding about this concept. We first investigate issues related to its definition as a set of local communities that are linked by dispersal of multiple potentially interacting species. We then identify four paradigms for metacommunities: the patch-dynamic view, the species-sorting view, the mass effects view and the neutral view, that each emphasizes different processes of potential importance in metacommunities. These have somewhat distinct intellectual histories and we discuss elements related to their potential future synthesis. We then use this framework to discuss why the concept is useful in modifying existing ecological thinking and illustrate this with a number of both theoretical and empirical examples. As ecologists strive to understand increasingly complex mechanisms and strive to work across multiple scales of spatio-temporal organization, concepts like the metacommunity can provide important insights that frequently contrast with those that would be obtained with more conventional approaches based on local communities alone.

Innovation, organizational capabilities, and the born-global firm

Abstract: We investigate born-global firms as early adopters of internationalization – that is, companies that expand into foreign markets and exhibit international business prowess and superior performance, from or near their founding. Our explication highlights the critical role of innovative culture, as well as knowledge and capabilities, in this unique breed of international, entrepreneurial firm. Case studies are analyzed to better understand the early internationalization phenomenon and reveal key orientations and strategies that engender international success among these innovative firms. Case findings are then validated in a survey-based study. Despite the scarce resources typical of young firms, our findings reveal that born-global firms leverage a distinctive mix of orientations and strategies that allow them to succeed in diverse international markets. Findings have important implications for the internationalization of contemporary firms.

Deliberate practice and the acquisition and maintenance of expert performance in medicine and related domains.

Abstract: The factors that cause large individual differences in professional achievement are only partially understood. Nobody becomes an outstanding professional without experience, but extensive experience does not invariably lead people to become experts. When individuals are first introduced to a professional domain after completing their education, they are often overwhelmed and rely on help from others to accomplish their responsibilities. After months or years of experience, they attain an acceptable level of proficiency and are able to work independently. Although everyone in a given domain tends to improve with experience initially, some develop faster than others and continue to improve during ensuing years. These individuals are eventually recognized as experts and masters. In contrast, most professionals reach a stable, average level of performance within a relatively short time frame and maintain this mediocre status for the rest of their careers. The nature of the individual differences that cause the large variability in attained performance is still debated. The most common explanation is that achievement in a given domain is limited by innate factors that cannot be changed through experience and training; hence, limits of attainable performance are determined by one’s basic endowments, such as abilities, mental capacities, and innate talents. Educators with this widely held view of professional development have focused on identifying and selecting students who possess the necessary innate talents that would allow them to reach expert levels with adequate experience. Therefore, the best schools and professional organizations nearly always rely on extensive testing and interviews to find the most talented applicants. This general view also explains age-related declines in professional achievement in terms of the inevitable reductions in general abilities and capacities believed to result from aging. In this article, I propose an alternative framework to account for individual differences in attained professional development, as well as many aspects of age-related decline. This framework is based on the assumption that acquisition of expert performance requires engagement in deliberate practice and that continued deliberate practice is necessary for maintenance of many types of professional performance. In order to contrast this alternative framework with the traditional view, I first describe the account based on innate talent. I then provide a brief review of the evidence on deliberate practice in the acquisition of expert performance in several performance domains, including music, chess, and sports. Finally, I review evidence from the acquisition and maintenance of expert performance in medicine and examine the role of deliberate practice in this domain.

Composition of the depleted mantle

Abstract: [1] We present an estimate for the composition of the depleted mantle (DM), the source for mid-ocean ridge basalts (MORBs). A combination of approaches is required to estimate the major and trace element abundances in DM. Absolute concentrations of few elements can be estimated directly, and the bulk of the estimates is derived using elemental ratios. The isotopic composition of MORB allows calculation of parent-daughter ratios. These estimates form the “backbone” of the abundances of the trace elements that make up the Coryell-Masuda diagram (spider diagram). The remaining elements of the Coryell-Masuda diagram are estimated through the composition of MORB. A third group of estimates is derived from the elemental and isotopic composition of peridotites. The major element composition is obtained by subtraction of a low-degree melt from a bulk silicate Earth (BSE) composition. The continental crust (CC) is thought to be complementary to the DM, and ratios that are chondritic in the CC are expected to also be chondritic in the DM. Thus some of the remaining elements are estimated using the composition of CC and chondrites. Volatile element and noble gas concentrations are estimated using constraints from the composition of MORBs and ocean island basalts (OIBs). Mass balance with BSE, CC, and DM indicates that CC and this estimate of the DM are not complementary reservoirs.

Centralized channel assignment and routing algorithms for multi-channel wireless mesh networks

Abstract: The IEEE 802.11 Wireless LAN standards allow multiple non-overlapping frequency channels to be used simultaneously to increase the aggregate bandwidth available to end-users. Such bandwidth aggregation capability is routinely used in infrastructure mode operation, where the traffic to and from wireless nodes is distributed among multiple interfaces of an access point or among multiple access points to balance the traffic load. However, bandwidth aggregation is rarely used in the context of multi-hop 802.11-based LANs that operate in the ad hoc mode. Most past research efforts that attempt to exploit multiple radio channels require modifications to the MAC protocol and therefore do not work with commodity 802.11 interface hardware. In this paper, we propose and evaluate one of the first multi-channel multi-hop wireless ad-hoc network architectures that can be built using standard 802.11 hardware by equipping each node with multiple network interface cards (NICs) operating on different channels. We focus our attention on wireless mesh networks that serve as the backbone for relaying end-user traffic from wireless access points to the wired network. The idea of exploiting multiple channels is particularly appealing in wireless mesh networks because of their high capacity requirements to support backbone traffic. To reap the full performance potential of this architecture, we develop a set of centralized channel assignment, bandwidth allocation, and routing algorithms for multi-channel wireless mesh networks. A detailed performance evaluation shows that with intelligent channel and bandwidth assignment, equipping every wireless mesh network node with just 2 NICs operating on different channels can increase the total network goodput by a factor of up to 8 compared with the conventional single-channel ad hoc network architecture.

The neurobiology of pair bonding

Abstract: A neurobiological model for pair-bond formation has emerged from studies in monogamous rodents. The neuropeptides oxytocin and vasopressin contribute to the processing of social cues necessary for individual recognition. Mesolimbic dopamine is involved in reinforcement and reward learning. Concurrent activation of neuropeptide and dopamine receptors in the reward centers of the brain during mating results in a conditioned partner preference, observed as a pair bond. Differential regulation of neuropeptide receptor expression may explain species differences in the ability to form pair bonds. These and other studies discussed here have intriguing implications for the neurobiology of social attachment in our own species.

Kindergarten Prediction of Reading Skills: A Longitudinal Comparative Analysis

Abstract: There is considerable focus in public policy on screening children for reading difficulties. Sixty years of research have not resolved questions of what constructs assessed in kindergarten best predict subsequent reading outcomes. This study assessed the relative importance of multiple measures obtained in a kindergarten sample for the prediction of reading outcomes at the end of 1st and 2nd grades. Analyses revealed that measures of phonological awareness, letter sound knowledge, and naming speed consistently accounted for the unique variance across reading outcomes whereas measures of perceptual skills and oral language and vocabulary did not. These results show that measures of letter name and letter sound knowledge, naming speed, and phonological awareness are good predictors of multiple reading outcomes in Grades 1 and 2.

An assessment of the use of structural equation modeling in strategic management research

Abstract: Structural equation modeling (SEM) is a powerful, yet complex, analytical technique. The use of SEM to examine strategic management phenomena has increased dramatically in recent years, suggesting that a critical evaluation of the technique's implementation is needed. We compared the use of SEM in 92 strategic management studies published in nine prominent journals from 1984 to 2002 to guidelines culled from methodological research. We found that the use and reporting of SEM often have been less than ideal, indicating that authors may be drawing erroneous conclusions about relationships among variables. Given these results, we offer suggestions for researchers on how to better deploy SEM within future inquiry. Copyright © 2004 John Wiley & Sons, Ltd.

Information Processing, Knowledge Development, and Strategic Supply Chain Performance

Abstract: Little is known about why some supply chains perform well while others do not. Drawing on the knowledge-based view of the firm and theory from the information processing and organizational learning...

Service quality dimensions: an examination of Grönroos’s service quality model

Abstract: Service quality researchers to date have paid scant attention to the issue of the dimensions of service quality. Much of the earlier work accepted the content measured by the SERVQUAL instrument. Following the argument that SERVQUAL only reflects the service delivery process, the study empirically examines the European perspective (i.e. Gronroos' model) suggesting that service quality consists of three dimensions, technical, functional and image, and that image functions as a filter in service quality perception. The results from a cell phone service sample revealed that Gronroos' model is a more appropriate representation of service quality than the American perspective with its limited concentration on the dimension of functional quality.

A new ZVS bidirectional DC-DC converter for fuel cell and battery application

Abstract: This paper presents a new zero-voltage-switching (ZVS) bidirectional dc-dc converter. Compared to the traditional full and half bridge bidirectional dc-dc converters for the similar applications, the new topology has the advantages of simple circuit topology with no total device rating (TDR) penalty, soft-switching implementation without additional devices, high efficiency and simple control. These advantages make the new converter promising for medium and high power applications especially for auxiliary power supply in fuel cell vehicles and power generation where the high power density, low cost, lightweight and high reliability power converters are required. The operating principle, theoretical analysis, and design guidelines are provided in this paper. The simulation and the experimental verifications are also presented.

Petroleomics: The Next Grand Challenge for Chemical Analysis

Abstract: Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry has recently revealed that petroleum crude oil contains heteroatom-containing (N,O,S) organic components having more than 20 000 distinct elemental compositions (CcHhNnOoSs). It is therefore now possible to contemplate the ultimate characterization of all of the chemical constituents of petroleum, along with their interactions and reactivity, a concept we denote as “petroleomics”. Such knowledge has already proved capable of distinguishing petroleum and its distillates according to their geochemical origin and maturity, distillation cut, extraction method, catalytic processing, etc. The key features that have opened up this new field have been (a) ultrahigh-resolution FT-ICR mass analysis, specifically, the capability to resolve species differing in elemental composition by C3 vs SH4 (i.e., 0.0034 Da); (b) higher magnetic field to cover the whole mass range at once; (c) dynamic range extension by external mass filtering; and ...

SUSY Les Houches accord: interfacing SUSY spectrum calculators, decay packages, and event generators

Abstract: An accord specifying a unique set of conventions for supersymmetric extensions of the Standard Model together with generic file structures for 1) supersymmetric model specifications and input parameters, 2) electroweak scale supersymmetric mass and coupling spectra, and 3) decay tables is presented, to provide a universal interface between spectrum calculation programs, decay packages, and high energy physics event generators.

Real Time Scheduling Theory: A Historical Perspective

Abstract: In this 25th year anniversary paper for the IEEE Real Time Systems Symposium, we review the key results in real-time scheduling theory and the historical events that led to the establishment of the current real-time computing infrastructure. We conclude this paper by looking at the challenges ahead of us.

The theory of planned behavior and Internet purchasing

Abstract: Several opinion polls have found that many consumers resist making purchases via the Internet because of their concerns about the privacy of the personal information they provide to Internet merchants. Using the theory of planned behavior as its basis, this study investigated the relationships among beliefs about Internet privacy and trustworthiness, along with beliefs about perceived behavioral control and the expectations of important others, and online purchasing behavior. Data were collected from 193 college students. Analysis of the data indicates that beliefs about trustworthiness positively affect attitudes toward buying online, which in turn positively affect purchasing behavior. Beliefs about self‐efficacy regarding purchasing positively affect perceived behavioral control, which in turn affects online purchasing behavior. In short, respondents who believed in the trustworthiness of the Internet and in their own abilities to buy online were more likely to make Internet purchases than were those without such beliefs.

Identified charged particle spectra and yields in Au + Au collisions at √sNN = 200 GeV

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.

Development and Validation of the Secondary Traumatic Stress Scale

Abstract: Objective: To describe the development and validation of the Secondary Traumatic Stress Scale (STSS), a 17-item instrument designed to measure intrusion, avoidance, and arousal symptoms associated with indirect exposure to traumatic events via one’s professional relationships with traumatized clients. Method: A sample of 287 licensed social workers completed a mailed survey containing the STSS and other relevant survey items. Results: Evidence was found for reliability, convergent and discriminant validity, and factorial validity. Conclusions: The STSS fills a need for reliable and valid instruments specifically designed to measure the negative effects of social work practice with traumatized populations. The instrument may be used to undertake empirical investigation into the prevention and amelioration of secondary traumatic stress among social work practitioners.

The Impact of United States Recreational Fisheries on Marine Fish Populations

Abstract: We evaluated the commercial and recreational fishery landings over the past 22 years, first at the national level, then for populations of concern (those that are overfished or experiencing overfishing), and finally by region. Recreational landings in 2002 account for 4% of total marine fish landed in the United States. With large industrial fisheries excluded (e.g., menhaden and pollock), the recreational component rises to 10%. Among populations of concern, recreational landings in 2002 account for 23% of the total nationwide, rising to 38% in the South Atlantic and 64% in the Gulf of Mexico. Moreover, it affects many of the most-valued overfished species-including red drum, bocaccio, and red snapper-all of which are taken primarily in the recreational fishery.

Early indicators of autism spectrum disorders in the second year of life.

Abstract: Three groups of 18 children were selected for this study, one group with autism spectrum disorders (ASD), one group with developmental delays in which ASD was ruled out (DD), and one group with typical development (TD), from a pool of 3026 children who were screened with the Communication and Symbolic Behavior Scales Developmental Profile (CSBS DP, Wetherby & Prizant, 2002) Infant-Toddler Checklist under 24 months of age. The CSBS DP Behavior Sample was videotaped on selected children as a second-level evaluation during the second year of life. The Infant-Toddler Checklist had a sensitivity and specificity of 88.9% for this sample of children. Significant group differences were found on the Infant-Toddler Checklist and the Behavior Sample, however, these differences did not distinguish children with ASD and DD with high accuracy. The videotapes of the Behavior Sample were reanalyzed to identify red flags of ASD. Nine red flags differentiated children in the ASD group from both the DD and TD groups and four red flags differentiated children in the ASD Group from the TD group but not the DD group. These 13 red flags were found to discriminate the three groups with a correct classification rate of 94.4%.

Gender and Emotion in the United States: Do Men and Women Differ in Self‐Reports of Feelings and Expressive Behavior?1

Abstract: U.S. emotion culture contains beliefs that women are more emotional and emotionally expressive than men and that men and women differ in their experience and expression of specific emotions. Using data from the 1996 emotions module of the GSS, the authors investigate whether men and women differ in self‐reports of feelings and expressive behavior, evaluating whether the patterns observed for men and women are consistent with cultural beliefs as well as predictions from two sociological theories about emotion and two sociological theories about gender. Surprisingly, self‐reports do not support cultural beliefs about gender differences in the frequency of everyday subjective feelings in general. Men and women do, however, differ in the frequency of certain positive and negative feelings, which is explained by their difference in social position. The implications of the findings for theory and research on both gender and emotion are discussed.

Enhanced partner preference in a promiscuous species by manipulating the expression of a single gene

Abstract: The molecular mechanisms underlying the evolution of complex behaviour are poorly understood. The mammalian genus Microtus provides an excellent model for investigating the evolution of social behaviour. Prairie voles (Microtus ochrogaster) exhibit a monogamous social structure in nature, whereas closely related meadow voles (Microtus pennsylvanicus) are solitary and polygamous. In male prairie voles, both vasopressin and dopamine act in the ventral forebrain to regulate selective affiliation between adult mates, known as pair bond formation, as assessed by partner preference in the laboratory. The vasopressin V1a receptor (V1aR) is expressed at higher levels in the ventral forebrain of monogamous than in promiscuous vole species, whereas dopamine receptor distribution is relatively conserved between species. Here we substantially increase partner preference formation in the socially promiscuous meadow vole by using viral vector V1aR gene transfer into the ventral forebrain. We show that a change in the expression of a single gene in the larger context of pre-existing genetic and neural circuits can profoundly alter social behaviour, providing a potential molecular mechanism for the rapid evolution of complex social behaviour.

Coral mucus functions as an energy carrier and particle trap in the reef ecosystem

Abstract: Zooxanthellae, endosymbiotic algae of reef-building corals, substantially contribute to the high gross primary production of coral reefs1, but corals exude up to half of the carbon assimilated by their zooxanthellae as mucus2,3 Here we show that released coral mucus efficiently traps organic matter from the water column and rapidly carries energy and nutrients to the reef lagoon sediment, which acts as a biocatalytic mineralizing filter In the Great Barrier Reef, the dominant genus of hard corals, Acropora, exudes up to 48 litres of mucus per square metre of reef area per day Between 56% and 80% of this mucus dissolves in the reef water, which is filtered through the lagoon sands Here, coral mucus is degraded at a turnover rate of at least 7% per hour Detached undissolved mucus traps suspended particles, increasing its initial organic carbon and nitrogen content by three orders of magnitude within 2 h Tidal currents concentrate these mucus aggregates into the lagoon, where they rapidly settle Coral mucus provides light energy harvested by the zooxanthellae and trapped particles to the heterotrophic reef community, thereby establishing a recycling loop that supports benthic life, while reducing loss of energy and nutrients from the reef ecosystem

Phylogeny and Divergence-Date Estimates of Rapid Radiations in Muroid Rodents Based on Multiple Nuclear Genes

Abstract: The muroid rodents are the largest superfamily of mammals, containing nearly one third of all mammal species. We report on a phylogenetic study comprising 53 genera sequenced for four nuclear genes, GHR, BRCA1, RAG1, and c-myc, totaling up to 6400 nucleotides. Most relationships among the subfamilies are resolved. All four genes yield nearly identical phylogenies, differing only in five key regions, four of which may represent particularly rapid radiations. Support is very strong for a fundamental division of the mole rats of the subfamilies Spalacinae and Rhizomyinae from all other muroids. Among the other "core" muroids, a rapid radiation led to at least four distinct lineages: Asian Calomyscus ,a nAfrican clade of at least four endemic subfamilies, including the diverse Nesomyinae of Madagascar, a hamster clade with maximum diversity in the New World, and an Old World clade including gerbils and the diverse Old World mice and rats (Murinae). The Deomyinae, recently removed from the Murinae, is well supported as the sister group to the gerbils (Gerbillinae). Four key regions appear to represent rapid radiations and, despite a large amount of sequence data, remain poorly resolved: the base of the "core" muroids, among the five cricetid (hamster) subfamilies, within a large clade of Sigmodontinae endemic to South America, and among major geographic lineages of Old World Murinae. Because of the detailed taxon sampling within the Murinae, we are able to refine the fossil calibration of a rate-smoothed molecular clock and apply this clock to date key events in muroid evolution. We calculate rate differences among the gene regions and relate those differences to relative contribution of each gene to the support for various nodes. The among-gene variance in support is greatest for the shortest branches. We present a revised classification for this largest but most unsettled mammalian superfamily. (Adaptive radiation; calibration; classification; molecular clock; Murinae; Sigmodontinae.)

Analysis of planar shapes using geodesic paths on shape spaces

Abstract: For analyzing shapes of planar, closed curves, we propose differential geometric representations of curves using their direction functions and curvature functions. Shapes are represented as elements of infinite-dimensional spaces and their pairwise differences are quantified using the lengths of geodesics connecting them on these spaces. We use a Fourier basis to represent tangents to the shape spaces and then use a gradient-based shooting method to solve for the tangent that connects any two shapes via a geodesic. Using the Surrey fish database, we demonstrate some applications of this approach: 1) interpolation and extrapolations of shape changes, 2) clustering of objects according to their shapes, 3) statistics on shape spaces, and 4) Bayesian extraction of shapes in low-quality images.

Learner motivation and E-learning design: A multinationally validated process

Abstract: A general model for motivational design of instruction is described and reviewed in terms of its application to E-learning contexts. Following a description of what is meant by E-learning environments and an overview of the four category model and design process known as the ARCS model, a variety of studies are summarized. The ARCS model is based on a synthesis of motivational concepts and a problem-solving approach to design, rather than the application of specific motivational solutions that are advocated without regard to the specific characteristics of a given situation. The first group of reviewed studies illustrates the results of testing the motivational design process in several different E-learning settings, in relation to learner self-regulation and in terms of the interaction of personality characteristics and motivational strategies. The second group of studies includes tests of the validity of a simplified motivational design process that has been used in diverse types of E-learning settings,...

Gender As Social Institution

Abstract: This article encourages sociologists to study gender as a social institution. Noting that scholars apply the institution concept to highly disparate phenomena, it reviews the history of the concept in twentieth-century sociology. The defining characteristic most commonly attributed to social institution is endurance (or persistence over time) while contemporary uses highlight practices, conflict, identity, power, and change. I identify twelve criteria for deciding whether any phenomenon is a social institution. I conclude that treating gender as an institution will improve gender scholarship and social theory generally, increase awareness of gender’s profound sociality, offer a means of linking diverse theoretical and empirical work, and make gender’s invisible dynamics and complex intersections with other institutions more apparent and subject to critical analysis and change.

Securing the upstream supply chain: a risk management approach

Abstract: Supply managers must manage many risks in their increasingly competitive environments. Traditionally this meant buffering against uncertainties, which sub‐optimized operational performance. Risk management can be a more effective approach to deal with these uncertainties by identifying potential losses. This conceptual study proposes that situational factors‐ degree of product technology, security needs, the relative importance of the supplier, and the purchasers’ prior experience with the situation should be taken into consideration when determining the level of risk management in the supply chain. Doing so can avoid unforeseen losses and lead to better anticipation of risks.

Protein-only transmission of three yeast prion strains

Abstract: Key questions regarding the molecular nature of prions are how different prion strains can be propagated by the same protein and whether they are only protein1,2,3. Here we demonstrate the protein-only nature of prion strains in a yeast model, the [PSI] genetic element that enhances the read-through of nonsense mutations in the yeast Saccharomyces cerevisiae4,5. Infectious fibrous aggregates containing a Sup35 prion-determining amino-terminal fragment labelled with green fluorescent protein were purified from yeast harbouring distinctive prion strains. Using the infectious aggregates as ‘seeds’, elongated fibres were generated in vitro from the bacterially expressed labelled prion protein. De novo generation of strain-specific [PSI] infectivity was demonstrated by introducing sheared fibres into uninfected yeast hosts. The cross-sectional morphology of the elongated fibres generated in vitro was indistinguishable from that of the short yeast seeds, as visualized by electron microscopy. Electron diffraction of the long fibres showed the 4.7 A spacing characteristic of the cross-beta structure of amyloids. The fact that the amyloid fibres nucleated in vitro propagate the strain-specific infectivity of the yeast seeds implies that the heritable information of distinct prion strains must be encoded by different, self-propagating cross-beta folding patterns of the same prion protein.