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Showing papers by "Kent State University published in 2007"


Journal ArticleDOI
TL;DR: In this paper, a worldwide panel of experts on the study and treatment of those exposed to disaster and mass violence to extrapolate from related fields of research, and to gain consensus on intervention principles.
Abstract: Given the devastation caused by disasters and mass violence, it is critical that intervention policy be based on the most updated research findings. However, to date, no evidence-based consensus has been reached supporting a clear set of recommendations for intervention during the immediate and the mid-term post mass trauma phases. Because it is unlikely that there will be evidence in the near or mid-term future from clinical trials that cover the diversity of disaster and mass violence circumstances, we assembled a worldwide panel of experts on the study and treatment of those exposed to disaster and mass violence to extrapolate from related fields of research, and to gain consensus on intervention principles. We identified five empirically supported intervention principles that should be used to guide and inform intervention and prevention efforts at the early to mid-term stages. These are promoting: 1) a sense of safety, 2) calming, 3) a sense of self- and community efficacy, 4) connectedness, and 5) hope.

904 citations


Journal ArticleDOI
TL;DR: Together, these results imply that the geometry, agglomeration state, and surface resistance of nanoparticles are the main variables controlling thermal conductivity enhancement in nanofluids.
Abstract: In recent years many experimentalists have reported an anomalously enhanced thermal conductivity in liquid suspensions of nanoparticles. Despite the importance of this effect for heat transfer applications, no agreement has emerged about the mechanism of this phenomenon, or even about the experimentally observed magnitude of the enhancement. To address these issues, this paper presents a combined experimental and theoretical study of heat conduction and particle agglomeration in nanofluids. On the experimental side, nanofluids of alumina particles in water and ethylene glycol are characterized using thermal conductivity measurements, viscosity measurements, dynamic light scattering, and other techniques. The results show that the particles are agglomerated, with an agglomeration state that evolves in time. The data also show that the thermal conductivity enhancement is within the range predicted by effective medium theory. On the theoretical side, a model is developed for heat conduction through a fluid containing nanoparticles and agglomerates of various geometries. The calculations show that elongated and dendritic structures are more efficient in enhancing the thermal conductivity than compact spherical structures of the same volume fraction, and that surface (Kapitza) resistance is the major factor resulting in the lower than effective medium conductivities measured in our experiments. Together, these results imply that the geometry, agglomeration state, and surface resistance of nanoparticles are the main variables controlling thermal conductivity enhancement in nanofluids.

700 citations


Journal ArticleDOI
TL;DR: Examination of attention and executive function in a cross-section of 408 healthy persons across the adult life span shows that BMI was inversely related to performance on all cognitive tests and suggests that this relationship does not vary with age.

640 citations


Journal ArticleDOI
TL;DR: The factor structure of the EQ was replicated in a clinical sample of individuals in remission from depression, and the decentering factor evidenced a negative relationship to concurrent levels of depression symptoms.

597 citations


Journal ArticleDOI
TL;DR: A theoretical sampling guide that was developed by the authors' research team to facilitate systematic decision making and to enhance the audit trail relative to theoretical sampling is described, and an example of how the guide was used to develop a category is presented.
Abstract: Theoretical sampling is a hallmark of grounded theory methodology, and yet there is little guidance available for researchers on how to implement this process. A review of recently published grounded theory studies in Qualitative Health Research revealed that researchers often indicate that they use theoretical sampling to choose new participants, to modify interview guides, or to add data sources as a study progresses, but few describe how theoretical sampling is implemented in response to emergent findings. In this article, two issues that arose relative to theoretical sampling in an ongoing grounded theory study are discussed. A theoretical sampling guide that was developed by the authors' research team to facilitate systematic decision making and to enhance the audit trail relative to theoretical sampling is described, and an example of how the guide was used to develop a category is presented.

545 citations


Journal ArticleDOI
TL;DR: Heightened intensity of emotions was better characterized separately, suggesting it may relate more strongly to dispositional emotion generation or emotionality than other measures of emotion function and dysregulation.

470 citations


Journal ArticleDOI
TL;DR: A taxonomy is derived from the analysis of this literature and presents the work via four dimensions: the type of software repositories mined, the purpose, the adopted/invented methodology used, and the evaluation method.
Abstract: A comprehensive literature survey on approaches for mining software repositories (MSR) in the context of software evolution is presented. In particular, this survey deals with those investigations that examine multiple versions of software artifacts or other temporal information. A taxonomy is derived from the analysis of this literature and presents the work via four dimensions: the type of software repositories mined (what), the purpose (why), the adopted/invented methodology used (how), and the evaluation method (quality). The taxonomy is demonstrated to be expressive (i.e., capable of representing a wide spectrum of MSR investigations) and effective (i.e., facilitates similarities and comparisons of MSR investigations). Lastly, a number of open research issues in MSR that require further investigation are identified.

460 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated residents' attitudes towards tourism in a rural village of Bigodi, Uganda and found that residents have consistently positive attitudes toward tourism and that tourists bring random good fortune.

440 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated whether psychological distress is reduced or increased by posttraumatic growth in other trauma contexts and found that individuals were deeply involved in translating growth cognitions to growth actions in their research on the forced disengagement of settlers from Gaza.
Abstract: Recent studies related to global terrorism have suggested the potential of posttraumatic growth (PTG) following experiences of terror exposure. However, investigations of whether psychological distress is reduced or increased by PTG in other trauma contexts have been inconsistent. Results from our studies conducted in New York following the attacks of 11 September 2001 and in Israel during recent tumultuous periods of violence and terrorism, the Al Aqsa Intifada, have found posttraumatic growth to be related to greater psychological distress, more right-wing political attitudes, and support for retaliatory violence. Only when individuals were deeply involved in translating growth cognitions to growth actions in our research on the forced disengagement of settlers from Gaza did we find positive benefit in posttraumatic growth. Findings are considered within the framework of a new formulation of action-focused growth. De recentes recherches en rapport avec le terrorisme international ont souligne le potentiel du developpement post-traumatique (PTG) decoulant de la confrontation a la terreur. Toutefois, les travaux cherchant a savoir si la detresse psychologique etait attenuee ou accentuee par le PTG dans d’autres contextes traumatiques se sont reveles contradictoires. Nos investigations a New York apres l’attentat du 11 septembre 2001 et en Israel durant des periodes recentes de violence et de terrorisme, la seconde Intifada, ont montre que le developpement post-traumatique etait plutot liea une grande detresse psychologique, a des opinions politiques de droite et a une attente de represailles. On a observe lors du demenagement obligatoire des colons de Gaza que ce n’est que lorsque les individus etaient profondement impliques dans la transformation des cognitions de developpement en actions de developpement que le developpement post-traumatique avait des retombees positives. Ces resultats sont apprehendes dans le cadre d’une nouvelle approche du developpement centre sur l’action.

424 citations


Journal ArticleDOI
TL;DR: A meta-analytic review of polysomnographic studies comparing sleep in people with and without PTSD suggested that sleep abnormalities exist in PTSD, and that some of the inconsistencies in prior findings may be explained by moderating variables.
Abstract: Although sleep complaints are common among patients with Posttraumatic stress disorder (PTSD), polysomnographic studies examining sleep abnormalities in PTSD have produced inconsistent results. To clarify discrepant findings, we conducted a meta-analytic review of 20 polysomnographic studies comparing sleep in people with and without PTSD. Results showed that PTSD patients had more stage 1 sleep, less slow wave sleep, and greater rapid-eye-movement density compared to people without PTSD. We also conducted exploratory analyses aimed at examining potential moderating variables (age, sex, and comorbid depression and substance use disorders). Overall, studies with a greater proportion of male participants or a low rate of comorbid depression tended to find more PTSD-related sleep disturbances. These findings suggest that sleep abnormalities exist in PTSD, and that some of the inconsistencies in prior findings may be explained by moderating variables.

387 citations


Journal ArticleDOI
B. I. Abelev1, Madan M. Aggarwal2, Zubayer Ahammed3, B. D. Anderson4  +365 moreInstitutions (45)
TL;DR: In this paper, the Star collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of the inclusive yield of nonphotonic electrons, which arise dominantly from semileptonic decays of heavy flavor mesons, over a broad range of transverse momenta (1.2
Abstract: The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of the inclusive yield of nonphotonic electrons, which arise dominantly from semileptonic decays of heavy flavor mesons, over a broad range of transverse momenta (1.2

Journal ArticleDOI
TL;DR: Findings support both direct and mediational effects of social resources on adult depression and PTSD symptoms in women with histories of CMM, suggesting that resources are key factors in psychological adjustment of C MM victims.

Journal ArticleDOI
TL;DR: The authors reviewed recent research that has shown some success in improving judgment accuracy and then argued that the most common method used to investigate metacomprehension accuracy may inadvertently constrain it.
Abstract: People's judgments about how well they have learned and comprehended text materials can be important for effectively regulating learning, but only if those judgments are accurate. Over two decades of research examining judgments of text learning—or metacomprehension—has consistently demonstrated that people's judgment accuracy is quite poor. We review recent research that has shown some success in improving judgment accuracy and then argue that the most common method used to investigate metacomprehension accuracy may inadvertently constrain it. We describe a new method that sidesteps some problems of the older method and present evidence showing how people can achieve high levels of metacomprehension accuracy.

Journal ArticleDOI
TL;DR: Independent of institutional history, children who were adopted ≥24 months had higher rates of behavior problems across many CBCL scales, including internalizing and externalizing problems, and time in the adoptive home, which also reflected age at testing, was positively associated with rates of problem behavior.
Abstract: Using the Child Behavior Checklist (CBCL), the rate and type of behavior problems associated with being reared in an institution prior to adoption were examined in 1,948, 4- through 18-year-old internationally adopted children, 899 of whom had experienced prolonged institutional care prior to adoption. The children's adoptions were decreed between 1990 and 1998 in Minnesota. Binomial logistic regression analyses revealed that early institutional rearing was associated with increased rates of attention and social problems, but not problems in either the internalizing or externalizing domains. Independent of institutional history, children who were adopted >or=24 months had higher rates of behavior problems across many CBCL scales, including internalizing and externalizing problems. In general, time in the adoptive home, which also reflected age at testing, was positively associated with rates of problem behavior. Thus, there was little evidence that the likelihood of behavior problems wane with time postadoption. Finally, children adopted from Russia/Eastern Europe appeared at greater risk of developing behavior problems in several domains compared to children adopted from other areas of the world.

Journal ArticleDOI
TL;DR: In this paper, the authors examine how corporate boards respond to investor demands for information on executive compensation practices and whether certain board and compensation committee characteristics, as proxies for board governance quality, are associated with the extent of board disclosure of compensation practices.
Abstract: This study examines how corporate boards respond to investor demands for information on executive compensation practices and whether certain board and compensation committee characteristics, as proxies for board governance quality, are associated with the extent of board disclosure of compensation practices. A unique feature of this study is the development of a comprehensive checklist of 23 compensation-related items. I validate this index by showing that the disclosure scores are inversely related to two measures of information asymmetry: bid-ask spread and return volatility. This provides evidence that greater compensation disclosure reduces information asymmetry. The study presents some evidence that boards with the power to act independently from management provide more details about executive compensation practices. Moreover, it contributes to the literature on corporate governance and disclosure by showing that greater commitment of directors to perform their duties results in greater transparency.

Journal ArticleDOI
B. I. Abelev1, Joseph Adams2, Madan M. Aggarwal3, Zubayer Ahammed4  +373 moreInstitutions (45)
TL;DR: In this article, the authors measured the midrapidity of the BNL Relativistic Heavy Ion Collider (RHIC) spectra and showed that the scaling of hadron production in p+p collisions seems to break down at higher mT and that there is a difference in the shape of the mT spectrum between baryons and mesons.
Abstract: We present strange particle spectra and yields measured at midrapidity in √s=200 GeV proton-proton (p+p) collisions at the BNL Relativistic Heavy Ion Collider (RHIC). We find that the previously observed universal transverse mass (m_T≡√pT2+m2) scaling of hadron production in p+p collisions seems to break down at higher mT and that there is a difference in the shape of the mT spectrum between baryons and mesons. We observe midrapidity antibaryon to baryon ratios near unity for Λ and Ξ baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum ⟨pT⟩ on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared with previous measurements made at the CERN Super Proton Synchrotron and Intersecting Storage Rings and in Fermilab experiments and with leading-order and next-to-leading-order string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from p+p collisions at RHIC energies have large contributions from gluon jets rather than from quark jets.

Journal ArticleDOI
TL;DR: This review surveys recent advances in the understanding of DUI, which is a peculiar system of cytoplasmic DNA inheritance that involves distinct maternal and paternal routes of mtDNA transmission, a novel extension of a mitochondrial gene (cox2), recombination, and periodic 'role-reversals' of the normally male and female-transmitted mitochondrial genomes.

Journal ArticleDOI
20 Dec 2007-Nature
TL;DR: It is shown that the Eocene south Asian raoellid artiodactyls are the sister group to whales and that Raoellids were aquatic waders, which indicates that aquatic life in this lineage occurred before the origin of the order Cetacea.
Abstract: Although the first ten million years of whale evolution are documented by a remarkable series of fossil skeletons, the link to the ancestor of cetaceans has been missing. It was known that whales are related to even-toed ungulates (artiodactyls), but until now no artiodactyls were morphologically close to early whales. Here we show that the Eocene south Asian raoellid artiodactyls are the sister group to whales. The raoellid Indohyus is similar to whales, and unlike other artiodactyls, in the structure of its ears and premolars, in the density of its limb bones and in the stable-oxygen-isotope composition of its teeth. We also show that a major dietary change occurred during the transition from artiodactyls to whales and that raoellids were aquatic waders. This indicates that aquatic life in this lineage occurred before the origin of the order Cetacea.

Journal ArticleDOI
TL;DR: This paper examined how discourses of diversity, circulating in educational policies, reflect and produce particular realities for people of color on university campuses and identified images of diversity and the problems and solutions related to diversity as represented in 21 diversity action plans generated throughout a 5-year period (1999-2004).
Abstract: Background: Universities continue to undertake a range of initiatives to combat inequities and build diverse, inclusive campuses. Diversity action plans are a primary means by which U.S. postsecondary institutions articulate their professed commitment to an inclusive and equitable climate for all members of the university and advance strategies to meet the challenges of an increasingly diverse society.Purpose: To examine, using critical race theory, how discourses of diversity, circulating in educational policies, reflect and produce particular realities for people of color on university campuses.Data Collection and Analysis:Data were collected from 20 U.S. land-grant universities. Line-by-line analysis, employing inductive and deductive coding strategies, was conducted to identify images of diversity and the problems and solutions related to diversity as represented in 21 diversity action plans generated throughout a 5-year period (1999-2004).Findings: Analysis reveals four predominant discourses shaping...

Journal ArticleDOI
TL;DR: Confirmatory factor analysis was used to compare a self-report measure, the PTSD Checklist, and a structured clinical interview, the Clinician-Administered PTSD Scale, in 2,960 utility workers exposed to the World Trade Center Ground Zero site, finding the latent structure of the PCL was slightly better represented by correlated reexperiencing, avoidance, dysphoria, and hyperarousal factors.
Abstract: Although posttraumatic stress disorder (PTSD) factor analytic research has yielded little support for the DSM-IV 3-factor model of reexperiencing, avoidance, and hyperarousal symptoms, no clear consensus regarding alternative models has emerged. One possible explanation is differential instrumentation across studies. In the present study, the authors used confirmatory factor analysis to compare a self-report measure, the PTSD Checklist (PCL), and a structured clinical interview, the Clinician-Administered PTSD Scale (CAPS), in 2,960 utility workers exposed to the World Trade Center Ground Zero site. Although two 4-factor models fit adequately for each measure, the latent structure of the PCL was slightly better represented by correlated reexperiencing, avoidance, dysphoria, and hyperarousal factors, whereas that of the CAPS was slightly better represented by correlated reexperiencing, avoidance, emotional numbing, and hyperarousal factors. After accounting for method variance, the model specifying dysphoria as a distinct factor achieved slightly better fit. Patterns of correlations with external variables provided additional support for the dysphoria model. Implications regarding the underlying structure of PTSD are discussed.

Journal ArticleDOI
TL;DR: This article explored the consequences of a transnational lifestyle for children who are left behind by migrant parents by using ethnographic fieldwork and interviews with a total of 141 members of Mexican transnational families.
Abstract: Today, many families find that they are unable to fulfill the goal of maintaining a household by living together under the same roof. Some members migrate internationally. This article addresses the consequences of a transnational lifestyle for children who are left behind by migrant parents. Using ethnographic fieldwork and interviews with a total of 141 members of Mexican transnational families, I explore how children who are left behind react to parents' migrations. I focus on how Mexican children manifest the competing pressures they feel surrounding parents' migrations and consequently shape family migration patterns. The article shows that children may experience power, albeit in different ways at different ages, while simultaneously being disadvantaged as dependents and in terms of their families' socioeconomic status. Key Words: children, family, Mexico, parent-child relations, transnationalism. Today, many families find that they are not able to fulfill the common goal of maintaining a household by living together under the same roof. By diversifying the residence of family members, families are able to take advantage of the disparities in the world economy. Able-bodied sons, daughters, brothers, sisters, aunts, uncles, mothers, and fathers move to areas where they can earn more for their human labor, whereas other family members remain in areas where the cost of living is low. Families move transnationally (Bryceson & Vuorela, 2002; Schmalzbauer, 2004). Although the international separation of families is not a new phenomenon (Foner, 2000; Nakano Glenn, 1983; Thomas & Znaniecki, 1927), one type of transnational family, mat in which mothers leave their children behind to work abroad, is increasingly common causing a plethora of new research focusing on the fives of these transnational families (Dreby, 2006; Hirsch, 2003; Hondagneu-Sotelo & Avila, 1997; Salazar Parrenas, 2005). This article addresses some of the consequences of the transnational lifestyle for children who are left behind by migrant parents. Using ethnographic fieldwork and interviews with a total of 141 members of Mexican transnational families, I explore how children who are left behind react to their parents' migrations. The overall study is based on interviews with migrant mothers and fathers residing in Central New Jersey, and children and their caregivers, most often grandparents, residing in the Mixtec region of south central Mexico. It analyzes the ways that members of transnational families accommodate changes in each other's lives over time. Here, I focus on how children who are left behind manifest the competing pressures they feel surrounding their parents' migrations and consequently shape families' migration patterns. Background Over the past 20 years, an emerging area of research on childhood has focused on understanding children as autonomous actors creating their own social worlds as distinct from and in dynamic relationship to those of the adults in their lives (Corsaro, 1997; Wrigley & Dreby, 2005). According to Qvortrup (1999), the new sociology of childhood has been relatively divorced from traditional, structural approaches to understanding children's fives, which emphasize the economic and political inequalities children experience in different societies. Primarily, ethnographic studies of children's social worlds have not been successful in describing how children's power, or lack of power, in their families and in other institutions relates to their families' relative position in the society in which they live (Wrigley & Dreby). In this article, I consider the power of children left behind in transnational families in relation to their families' social position as transnational migrants. I explore how children in Mexican transnational families are, on the one hand, the least powerful actors within their families, but on the other hand, very influential, both as intended recipients of the benefits their families gamer via international migration and as independent agents with divergent needs that are intensified by the separation from parents. …

Journal ArticleDOI
TL;DR: It is found that nurse educator and student knowledge improved significantly at intervention schools, as did intention to use mechanical lifting devices in the near future, and the curriculum module is ready for wide dissemination across nursing schools to reduce the risk of MSDs among nurses.
Abstract: Nursing schools in the United States have not been teaching evidence-based practices for safe patient handling, putting their graduates at risk for musculoskeletal disorders (MSDs). The specific aim of this study was to translate research related to safe patient handling into the curricula of nursing schools and evaluate the impact on nurse educators and students' intentions to use safe patient handling techniques. Nurse educators at 26 nursing schools received curricular materials and training; nursing students received the evidence-based curriculum module. There were three control sites. Questionnaires were used to collect data on knowledge, attitudes, and beliefs about safe patient handling for both nurse educators and students, pre- and post-training. In this study, we found that nurse educator and student knowledge improved significantly at intervention schools, as did intention to use mechanical lifting devices in the near future. We concluded that the curriculum module is ready for wide dissemination across nursing schools to reduce the risk of MSDs among nurses.

Journal ArticleDOI
TL;DR: A survey of residents in the metropolitan areas of these cities that gauged their perception of their own vulnerability to the heat, as well as their knowledge of heat warnings and the activities recommended to be undertaken to help mitigate the effects of the heat.
Abstract: To examine the efficacy of municipal heat watch warning systems, a thorough evaluation of the heat mitigation plans of four North American cities - Dayton (Ohio, USA), Philadelphia (Pennsylvania, USA), Phoenix (Arizona, USA), and Toronto (Ontario, Canada) - was undertaken. In concert with this evaluation was a survey of residents in the metropolitan areas of these cities that gauged their perception of their own vulnerability to the heat, as well as their knowledge of heat warnings and the activities recommended to be undertaken to help mitigate the effects of the heat. In total, 908 respondents participated in the telephone survey. Some of the key results indicate that knowledge of the heat warning was nearly universal (90%), and likely due to pervasive media coverage more than any other means. Though knowledge of the event was widespread, knowledge of what to do was less common. Only around half of all respondents mentioned that they changed their behavior, and despite the diversity of information available on mitigating heat vulnerability, most respondents stated that they merely “avoided the outdoors” at all costs. Though air conditioning was nearly ubiquitous among respondents, over a third mentioned that economic factors of energy costs were considered in terms of how long or whether the air conditioner was turned on.

Journal ArticleDOI
TL;DR: Findings revealed that CBT responders exhibited significantly greater gains in decentering compared with ADM responders, and high post acute treatment levels of decentering and low cognitive reactivity were associated with the lowest rates of relapse in the 18-month follow-up period.
Abstract: Z. V. Segal et al. (2006) demonstrated that depressed patients treated to remission through either antidepressant medication (ADM) or cognitive-behavioral therapy (CBT), but who evidenced mood-linked increases in dysfunctional thinking, showed elevated rates of relapse over 18 months. The current study sought to evaluate whether treatment response was associated with gains in decentering-the ability to observe one's thoughts and feelings as temporary, objective events in the mind-and whether these gains moderated the relationship between mood-linked cognitive reactivity and relapse of major depression. Findings revealed that CBT responders exhibited significantly greater gains in decentering compared with ADM responders. In addition, high post acute treatment levels of decentering and low cognitive reactivity were associated with the lowest rates of relapse in the 18-month follow-up period.

Journal ArticleDOI
TL;DR: In this paper, a vehicle-based survey was complemented by inspections with the reconnaissance boat along the Gulf Coast and the Mississippi Barrier Islands, showing that the lower floors of specially designed buildings were damaged by the surge of seawater and associated wave action.
Abstract: Hurricane Katrina (23–30 August 2005) struck low-lying coastal plains particularly vulnerable to storm surge flooding. Maximum storm surges, overland flow depths, and inundation distances were measured along the Gulf Coast of Florida, Alabama, Mississippi and Louisiana. The vehicle based survey was complemented by inspections with the reconnaissance boat along the Gulf Coast and the Mississippi Barrier Islands. The storm surge peaked to the East of Katrina’s path exceeding 10 meters in several locations along the Mississippi coastline. The storm surge measurements show that the lower floors of specially designed buildings were damaged by the surge of seawater and associated wave action, while the upper floors sustained minimal wind damage. Furthermore, the storm surge measurements along New Orleans’s Lake shore indicate that the 17th Street Canal levee failed prior to overtopping. The land loss on the barrier islands resulted in an increased vulnerability of the US Gulf Coast to future hurricane storm surges.

Journal ArticleDOI
TL;DR: Simulation results suggest that, where significant differences in T-RFLP diversity indices were found in previous work, these should be reinterpreted as a reflection of differences in community composition rather than a true difference in community diversity.
Abstract: Ecological diversity indices are frequently applied to molecular profiling methods, such as terminal restriction fragment length polymorphism (T-RFLP), in order to compare diversity among microbial communities. We performed simulations to determine whether diversity indices calculated from T-RFLP profiles could reflect the true diversity of the underlying communities despite potential analytical artifacts. These include multiple taxa generating the same terminal restriction fragment (TRF) and rare TRFs being excluded by a relative abundance (fluorescence) threshold. True community diversity was simulated using the lognormal species abundance distribution. Simulated T-RFLP profiles were generated by assigning each species a TRF size based on an empirical or modeled TRF size distribution. With a typical threshold (1%), the only consistently useful relationship was between Smith and Wilson evenness applied to T-RFLP data (TRF-Evar) and true Shannon diversity (H′), with correlations between 0.71 and 0.81. TRF-H′ and true H′ were well correlated in the simulations using the lowest number of species, but this correlation declined substantially in simulations using greater numbers of species, to the point where TRF-H′ cannot be considered a useful statistic. The relationships between TRF diversity indices and true indices were sensitive to the relative abundance threshold, with greatly improved correlations observed using a 0.1% threshold, which was investigated for comparative purposes but is not possible to consistently achieve with current technology. In general, the use of diversity indices on T-RFLP data provides inaccurate estimates of true diversity in microbial communities (with the possible exception of TRF-Evar). We suggest that, where significant differences in T-RFLP diversity indices were found in previous work, these should be reinterpreted as a reflection of differences in community composition rather than a true difference in community diversity.

Journal ArticleDOI
TL;DR: Factors, such as the ecological role of the taxa (generalists versus specialists), stage of decay, and time of exposure, appeared to be more important determinants of microbial community structure than leaf quality.
Abstract: Although fungi, bacteria, and specific bacterial taxa, such as the actinomycetes, have been studied extensively in various habitats, few studies have examined them simultaneously, especially on decomposing leaves in streams. In this study, sugar maple and white oak leaves were incubated in a stream in northeastern Ohio for 181 days during which samples were collected at regular intervals. Following DNA extraction, PCR-denaturing gradient gel electrophoresis (DGGE) was performed using fungus-, bacterium-, and actinomycete-specific primers. In addition, fungal and bacterial biomass was estimated. Fungal biomass differed on different days but not between leaves of the two species and was always greater than bacterial biomass. There were significant differences in bacterial biomass through time and between leaf types on some days. Generally, on the basis of DGGE, few differences in community structure were found for different leaf types. However, the ribotype richness of fungi was significantly greater than those of the bacteria and actinomycetes, which were similar to each other. Ribotype richness decreased toward the end of the study for each group except bacteria. Lack of differences between the two leaf types suggests that the microorganisms colonizing the leaf biofilm were primarily generalists that could exploit the resources of the leaves of either species equally well. Thus, we conclude that factors, such as the ecological role of the taxa (generalists versus specialists), stage of decay, and time of exposure, appeared to be more important determinants of microbial community structure than leaf quality.

Journal ArticleDOI
TL;DR: The case study shows that the ordinary kriging techniques may provide a powerful tool for interpolating the missing pixels in the SLC‐off ETM+ imagery, and demonstrates that the standardized ordinary cokriging provides little improvement in interpolation of the data gap.
Abstract: Using appropriate techniques to fill the data gaps in SLC-off ETM+ imagery may enable more scientific use of the data. The local linear histogram-matching technique chosen by USGS has limitations if the scenes being combined exhibit high temporal variability and radical differences in target radiance due, for example, to the presence of clouds. This study proposes using an alternative interpolation method, the kriging geostatistical technique, for filling the data gaps. The case study shows that the ordinary kriging techniques may provide a powerful tool for interpolating the missing pixels in the SLC-off ETM+ imagery. While the standardized ordinary cokriging has been shown to be particularly useful when samples of the variable to be predicted are sparse and samples of a second, related variable are plentiful, the case study demonstrates that it provides little improvement in interpolating the data gap in the SLC-off imagery.

Journal ArticleDOI
TL;DR: Findings demonstrate caregivers' vulnerability to the effects of stressors across three dimensions of health and also underscore the importance of subjective appraisals of stress.
Abstract: Objective: The authors examine the impact of two caregiving stressors, care receivers' behavior problems (an objective stressor) and caregivers' feelings of overload (a subjective stressor), on three dimensions of caregiver health. Method: The participants were 234 primary caregivers of elderly relatives with dementia living in the community who completed a comprehensive interview about their current care situation, including stressors and health. Results: Higher levels of both objective and subjective stressors were associated with all three dimensions of caregiver health: poorer self-reported health, more negative health behaviors, and greater use of health care services. The association between objective stressors and health was mediated by caregivers' feelings of overload. Conclusions: These findings demonstrate caregivers' vulnerability to the effects of stressors across three dimensions of health and also underscore the importance of subjective appraisals of stress.

Journal ArticleDOI
01 Aug 2007-Emotion
TL;DR: Support is provided for an interactive model in which rumination amplifies the deleterious effects of negative cognition.
Abstract: Response styles theory posits that rumination represents a trait vulnerability to depression. Recent evidence has suggested that rumination predicts changes in depression more strongly among individuals with high levels of negative cognition. Three studies evaluated this model of interactive vulnerabilities. Study 1 provided empirical support for the distinction between rumination and negative cognitive content. The next 2 studies investigated the interactive model in the laboratory. Study 2 randomly assigned participants to either ruminate or distract following a sad mood induction. This study found that rumination was more strongly associated with dysphoria among individuals who report high levels of negative cognition. Similarly, Study 3 found that rumination and negative cognition interact to predict changes in dysphoria across a no-task delay period following a sad mood induction. These studies provide support for an interactive model in which rumination amplifies the deleterious effects of negative cognition.