Biomedical subjects

David S Kosson

Publications and source records attributed to David S Kosson.

At least 19 recordsLinked to original sources

PubMed2007

Psychopathy and violent crime: a prospective study of the influence of socioeconomic status and ethnicity.

The relationship between psychopathy and violence is well-established. However, few studies have examined the extent to which this relationship is influenced by sociodemographic predictors of violent criminality. In this prospective study we examine the power of psychopathy to predict criminal violence across ethnicity and levels of socioeconomic status in 199 European American and African American U.S. county jail inmates. A Psychopathy x SES x Ethnicity interaction was identified such that among European Americans psychopathy predicted recidivism at lower levels of SES but was unrelated to recidivism at higher levels of SES. The predictive power of psychopathy was relatively stable across SES among African Americans. The implications of our results for psychopathy and violence prediction are discussed.

Adolescent↗

PubMed2007

Interhemispheric integration in psychopathic offenders.

The goal of the present study was to determine whether a reduced capacity for interhemispheric integration can explain the attention deficits seen in psychopathic individuals under conditions that place substantial demands on left-hemisphere-specific resources. The present study examined the performance of 54 incarcerated psychopathic and nonpsychopathic male offenders on a same-different global-local paradigm that permits manipulation of both the magnitude of processing demands and the demand for interhemispheric coordination. Prior studies with similar paradigms have demonstrated that the cerebral hemispheres can function more efficiently as relatively independent processors on simple tasks, whereas communication between the hemispheres improves performance when processing demands are heavy. Analyses indicated that psychopathic offenders are not deficient in interhemispheric integration but provided additional evidence consistent with the left hemisphere activation hypothesis of psychopathy.

Adolescent↗

PubMed2006

Scientific research, stakeholders, and policy: continuing dialogue during research on radionuclides on Amchitka Island, Alaska.

It is increasingly clear that a wide range of stakeholders should be included in the problem formulation phase of research aimed at solving environmental problems; indeed the inclusion of stakeholders at this stage has been formalized as an integral part of ecological risk assessment. In this paper, we advocate the additional inclusion of stakeholders in the refinement of research methods and protocols and in the execution of the research, rather than just at the final communication and reporting phase. We use a large study of potential radionuclide levels in marine biota around Amchitka Island as a case study. Amchitka Island, in the Aleutian Island Chain of Alaska, was the site of three underground nuclear tests (1965-1971). The overall objective of the biological component of the study was to collect a range of marine biota for radionuclide analysis that could provide data for assessing current food safety and provide a baseline for developing a plan to monitor human and ecosystem health in perpetuity. Stakeholders, including regulators (State of Alaska), resource trustees (US Fish and Wildlife Service, State of Alaska), representatives of the Aleut and Pribilof Island communities, the Department of Energy (DOE), and others, were essential for plan development. While these stakeholders were included in the initial problem formulation and approved science plan, we also included them in the refinement of protocols, selection of bioindicators, selection of a reference site, choice of methods of collection, and in the execution of the study itself. Meetings with stakeholders resulted in adding (or deleting) bioindicator species and tissues, prioritizing target species, refining sampling methods, and recruiting collection personnel. Some species were added because they were important subsistence foods for the Aleuts, and others were added because they were ecological equivalents to replace species deleted because of low population numbers. Two major refinements that changed the research thrust were (1) the inclusion of Aleut hunters and fishers on the biological expedition itself to ensure that subsistence foods and methods were represented, and (2) the addition of a fisheries biologist on a NOAA research trawler to allow sampling of commercial fishes. Although the original research design called for the collection of biota by Aleut subsistence fishermen, and by a commercial fishing boat, the research was modified with continued stakeholder input to actually include Aleuts and a fisheries biologist on the expeditions to ensure their representation. The inclusion of stakeholders during the development of protocols and the research itself improved the overall quality of the investigation, while making it more relevant to the interested and affected parties. Final responsibility for the design and execution of the research and radionuclide analysis rested with the researchers, but the process of stakeholder inclusion made the research more valuable as a source of credible information and for public policy decisions.

Alaska↗

PubMed2006

Evaluation of air permeability in layered unsaturated materials.

Field estimation of air permeability is important in the design and operation of soil-vapor extraction systems. Previous models have examined airflow in homogenous soils, incorporating leakage through a low-permeability cap either as a correction to the airflow equation or as a boundary condition. The dual leakage model solution developed here improves upon the previous efforts by adding a leaky lower boundary condition, allowing for the examination of airflow in heterogeneous layered soils. The dual leakage model is applied to the evaluation of pump tests at a pilot soil-vapor extraction system at the Savannah River Site in South Carolina. A thick, low-permeability, stiff clay layer divides the stratigraphy at the site into two units for evaluation. A modified version of the previous model, using the water table as the impermeable lower boundary, is used to evaluate the permeability of the low-permeability stiff clay layer (3.2 x 10(-10) cm(2)) and permeable sand (7.2 x 10(-7) cm(2)) beneath it. The stiff clay permeability estimate is used in the evaluation of the shallow unit. Permeability estimates of the shallow sand (3.8 x 10(-7) cm(2)) and kaolin cap (1.5 x 10(-9)cm(2)) were obtained with the dual leakage model. The shallow unit was evaluated using the previous model for comparison. The effects of anisotropy were investigated with a series of model simulations based on the shallow unit solution. The anisotropy sensitivity analysis suggests that increased anisotropy ratio or decreased axial permeability has a significant impact on the velocity profile at the lower boundary, especially at high values of the anisotropy ratio. This result may increase estimates of SVE removal rates for contaminants located at the interface of the lower boundary, typical of chlorinated solvent contamination.

Air Movements↗

PubMed2006

Radionuclides in marine macroalgae from Amchitka and Kiska Islands in the Aleutians: establishing a baseline for future biomonitoring.

Levels of radionuclides in seven species of marine brown algae and Ulva were determined to establish a baseline for the Northern Pacific Ocean/Bering Sea (Aleutian Islands). There were differences in levels among algal species and locations (Amchitka Island vs Kiska Island). No values were above the minimum detectable activity (MDA) level for (137)Cs, (129)I, (60)Co, (152)Eu, (90)Sr, and (99)Tc. There were interspecific differences in some radionuclides: Ulva lactuca (=Ulva fenestrata) had the highest levels of (241)Am, Alaria fistulosa had the highest levels of (239,240)Pu, and Fucus distichus (=Fucus gardneri) had the highest levels of (234)U, (235)U, and (238)U. However, levels of all radionuclides were generally low and near the MDA for all isotopes. Although Amchitka Island had higher levels of (239,240)Pu than Kiska, the differences were very small and not significant biologically. The data indicate that algae can be useful bioindicators of actinides because they accumulate them at very low environmental levels, allowing them to provide early warning of any potential seepage of radionuclides into the marine environment. Further, the data indicate that some species (the intertidal Fucus) are better accumulators than others, and these should be used as bioindicators in future monitoring schemes.

Alaska↗

PubMed2006

Characterization of Fe(III)-reducing enrichment cultures and isolation of Fe(III)-reducing bacteria from the Savannah River site, South Carolina.

The Savannah River site, South Carolina (SRS), has been subjected to heavy metal and radionuclide contamination. Dissimilatory Fe(III)-reducing bacteria, by reducing insoluble Fe(III) to soluble Fe(II), may enhance contaminant mobility through subsurface environments. In order to investigate populations of the indigenous iron-reducing microbes from the SRS, duplicate enrichment cultures were initiated using a 10% inoculum of 7 sediment/soil samples, and serial dilutions were made into Wolfe's minimal salts media amended with 50 mM Fe(III) floc, 10 mM acetate and 0.01% yeast extract. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to generate fingerprints of the cultures and track changes in the microbial communities through the dilutions. Cluster analysis determined the relatedness of individual fingerprints. Initial enrichment cultures exhibited complex fingerprints consisting of many individual T-RF peaks, and demonstrated low similarity between sites. After four serial dilutions the fingerprints were less complex and clustered at higher similarities. Several individual T-RF peaks became dominant in a majority of the fingerprints. Cloning and sequence analysis revealed the presence of microbes closely related to Clostridium and Bacillus species and to known iron reducers such as Geobacter species and Pantoea agglomerans. Several Fe(III)-reducing isolates related to Aeromonas, Bacillus and Clostridium species were obtained.

Aeromonas↗

PubMed2006

Forming, switching, and maintaining mental sets among psychopathic offenders during verbal and nonverbal tasks: another look at the left-hemisphere activation hypothesis.

Three hypotheses for cognitive deficits among psychopaths were tested: executive dysfunction, left hemisphere activation, and an interaction between the two. Twenty-one psychopathic and 23 nonpsychopathic criminal offenders identified with the Hare Psychopathy Checklist-Revised participated in verbal and visual-spatial tasks during which the level of executive processing demands was manipulated. Consistent with prior research, psychopathic offenders made more errors than controls, but only during the verbal task and only on trials with high executive demand. Within those trials, most errors occurred when set-maintenance demands were the highest. No response latency differences between groups were found.

Adolescent↗

PubMed2006

Effects of comorbid psychopathy on criminal offending and emotion processing in male offenders with antisocial personality disorder.

Antisocial personality disorder (ASPD) and psychopathy are two syndromes with substantial construct validity. To clarify relations between these syndromes, the authors evaluated 3 possibilities: (a) that ASPD with psychopathy and ASPD without psychopathy reflect a common underlying pathophysiology; (b) that ASPD with psychopathy and ASPD without psychopathy identify 2 distinct syndromes, similar in some respects; and (c) that most correlates of ASPD reflect its comorbidity with psychopathy. Participants were 472 incarcerated European American men who met Diagnostic and Statistical Manual (4th ed., American Psychiatric Association, 1994) criteria for ASPD and Psychopathy Checklist criteria for psychopathy, who met the criteria for ASPD but not for psychopathy, or who did not meet diagnostic criteria for either ASPD or psychopathy (controls). Both individuals with ASPD only and those with ASPD and psychopathy were characterized by more criminal activity than were controls. In addition, ASPD with psychopathy was associated with more severe criminal behavior and weaker emotion facilitation than ASPD alone. Group differences in the association between emotion dysfunction and criminal behavior suggest tentatively that ASPD with and ASPD without prominent psychopathic features may be distinct syndromes.

Adolescent↗

PubMed2006

Neuropsychological implications of selective attentional functioning in psychopathic offenders.

Several core characteristics of the psychopathic personality disorder (i.e., impulsivity, failure to attend to interpersonal cues) suggest that psychopaths suffer from disordered attention. However, there is mixed evidence from the cognitive literature as to whether they exhibit superior or deficient selective attention, which has led to the formation of several distinct theories of attentional functioning in psychopathy. The present experiment investigated participants' abilities to purposely allocate attentional resources on the basis of auditory or visual linguistic information and directly tested both theories of deficient or superior selective attention in psychopathy. Specifically, 91 male inmates at a county jail were presented with either auditory or visual linguistic cues (with and without distractors) that correctly indicated the position of an upcoming visual target in 75% of the trials. The results indicated that psychopaths did not exhibit evidence of superior selective attention in any of the conditions but were generally less efficient in shifting attention on the basis of linguistic cues, especially in regard to auditory information. Implications for understanding psychopaths' cognitive functioning and possible neuropsychological deficits are addressed.

Adolescent↗

PubMed2006

Factor structure of the Hare Psychopathy Checklist: Youth Version (PCL: YV) in incarcerated adolescents.

Two studies are reported on the underlying dimensions of the psychopathy construct in adolescents as measured by the Hare Psychopathy Checklist-Youth Version (PCL: YV; Forth, Kosson, & Hare, 2003). In Study 1, the PCL: YV item ratings for 505 male adolescents incarcerated in 5 different settings in North America were used to test the fit of 3 models that have been hypothesized to represent the structure of psychopathy in adults. A 4th model based on parceling PCL: YV items was also tested. In Study 2, these models were tested with a sample of 233 male adolescents incarcerated in 2 facilities in the United Kingdom. Model fit results indicated that the 18-item 4-factor model developed by Hare (2003) and a modified version of a 13-item 3-factor model developed by Cooke and Michie (2001) were associated with generally good fit. Because the 4-factor model is a less saturated model than the 3-factor model (better parameter to data point ratio), it survived a riskier test of disconfirmation. Implications for the nature of psychopathy in youth are discussed.

Adolescent↗

PubMed2006

Reliability and construct validity of the psychopathy checklist - revised for Latino, European American, and African American male inmates.

The utility of the psychopathy construct in predicting laboratory deficits, criminal behavior, response to intervention, and recidivism has been well documented in European American populations. However, less is known about the manifestation and correlates of psychopathy in Latino and African American populations. The present study examined the reliability and construct validity of the Psychopathy Checklist - Revised (PCL-R; R. D. Hare, 2003) in 83 Latino inmates compared with matched samples of African Americans and European Americans. Results provide preliminary evidence that the PCL-R provides a reliable and valid measure of psychopathy in Latinos, with generally similar patterns emerging across external correlates; however, some ethnic group differences were noted for relationships between psychopathy indicators and some external correlates.

Adolescent↗

PubMed2006

Heightened sensitivity to facial expressions of emotion in borderline personality disorder.

Individuals with borderline personality disorder (BPD) have been hypothesized to exhibit significant problems associated with emotional sensitivity. The current study examined emotional sensitivity (i.e., low threshold for recognition of emotional stimuli) in BPD by comparing 20 individuals with BPD and 20 normal controls on their accuracy in identifying emotional expressions. Results demonstrated that, as facial expressions morphed from neutral to maximum intensity, participants with BPD correctly identified facial affect at an earlier stage than did healthy controls. Participants with BPD were more sensitive than healthy controls in identifying emotional expressions in general, regardless of valence. These findings could not be explained by participants with BPD responding faster with more errors. Overall, results appear to support the contention that heightened emotional sensitivity may be a core feature of BPD.

Adult↗

PubMed2006

Development and application of a methodology for determining background groundwater quality at the Savannah River Site.

A statistical methodology formulated for defining background or baseline levels of constituents of concern in groundwater is presented. The methodology was developed for the case where prior delineation of unimpacted areas is not possible because of site history and a large set of groundwater monitoring measurements exists. Consideration was given to spatial and temporal trends, outliers, and final segregation of wells into impacted or unimpacted categories to develop probability distributions and summary statistics for each constituent evaluated. The formulated approaches were applied to groundwater monitoring data for the U.S. Department of Energy Savannah River Site facility, and results for four representative constituents (aluminum, arsenic, mercury, and tritium) are discussed.

Aluminum↗

PubMed2005

Science, policy, and stakeholders: developing a consensus science plan for Amchitka Island, Aleutians, Alaska.

With the ending of the Cold War, the US Department of Energy is responsible for the remediation of radioactive waste and disposal of land no longer needed for nuclear material production or related national security missions. The task of characterizing the hazards and risks from radionuclides is necessary for assuring the protection of health of humans and the environment. This is a particularly daunting task for those sites that had underground testing of nuclear weapons, where the radioactive contamination is currently inaccessible. Herein we report on the development of a Science Plan to characterize the physical and biological marine environment around Amchitka Island in the Aleutian chain of Alaska, where three underground nuclear tests were conducted (1965-1971). Information on the ecology, geology, and current radionuclide levels in biota, water, and sediment is necessary for evaluating possible current contamination and to serve as a baseline for developing a plan to ensure human and ecosystem health in perpetuity. Other information required includes identifying the location of the salt water/fresh water interface where migration to the ocean might occur in the future and determining groundwater recharge balances, as well as assessing other physical/geological features of Amchitka near the test sites. The Science Plan is needed to address the confusing and conflicting information available to the public about radionuclide risks from underground nuclear blasts in the late 1960s and early 1970s, as well as the potential for volcanic or seismic activity to disrupt shot cavities or accelerate migration of radionuclides into the sea. Developing a Science Plan involved agreement among regulators and other stakeholders, assignment of the task to the Consortium for Risk Evaluation with Stakeholder Participation, and development of a consensus Science Plan that dealt with contentious scientific issues. Involvement of the regulators (State of Alaska), resource trustees (U S Fish and Wildlife Service), representatives of the Aleut and Pribilof Island communities, and other stakeholders was essential for plan development and approval, although this created tensions because of the different objectives of each group. The complicated process of developing a Science Plan involved iterations and interactions with multiple agencies and organizations, scientists in several disciplines, regulators, and the participation of Aleut people in their home communities, as well as the general public. The importance of including all parties in all phases of the development of the Science Plan was critical to its acceptance by a broad range of regulators, agencies, resource trustees, Aleutian/Pribilof communities, and other stakeholders.

Alaska↗

PubMed2005

State-dependent executive deficits among psychopathic offenders.

Three hypotheses for cognitive deficits among psychopaths were tested: Response modulation, left hemisphere activation, and an interaction between the 2. Twenty-six psychopathic and 32 nonpsychopathic criminal offenders identified with the Hare Psychopathy Checklist-Revised were randomly assigned to left- and right-hemisphere activation groups. An auditory processing task was administered, such that the ability to classify nonverbal auditory signals and the ability to manage subgoals were assessed under left- and right-hemisphere activation conditions. The results showed that psychopaths' information processing in general, including response modulation, was deleteriously affected by left-hemisphere activation, supporting 2 of the 3 hypotheses tested. These results offer an explanation for inconsistent findings of executive deficits among psychopaths.

Adult↗

PubMed2005

Mobility of protozoa through narrow channels.

Microbes in the environment are profoundly affected by chemical and physical heterogeneities occurring on a spatial scale of millimeters to micrometers. Physical refuges are critical for maintaining stable bacterial populations in the presence of high predation pressure by protozoa. The effects of microscale heterogeneity, however, are difficult to replicate and observe using conventional experimental techniques. The objective of this research was to investigate the effect of spatial constraints on the mobility of six species of marine protozoa. Microfluidic devices were created with small channels similar in size to pore spaces in soil or sediment systems. Individuals from each species of protozoa tested were able to rapidly discover and move within these channels. The time required for locating the channel entrance from the source well increased with protozoan size and decreased with channel height. Protozoa of every species were able to pass constrictions with dimensions equal to or smaller than the individual's unconstrained cross-sectional area. Channel geometry was also an important factor affecting protozoan mobility. Linear rates of motion for various species of protozoa varied by channel size. In relatively wide channels, typical rates of motion were 300 to 500 microm s(-1) (or about 1 m per hour). As the channel dimensions decreased, however, motilities slowed more than an order of magnitude to 20 microm s(-1). Protozoa were consistently observed to exhibit several strategies for successfully traversing channel reductions. The empirical results and qualitative observations resulting from this research help define the physical limitations on protozoan grazing, a critical process affecting microbes in the environment.

Animals↗

PubMed2004

Psychopathy is related to negative affectivity but not to anxiety sensitivity.

Although the hypothesis that psychopathic individuals are characterized by a reduced capacity for experiencing anxiety is central to many theories of psychopathy, most prior studies have examined anxiety and fear measures generally considered outdated in the literature. Moreover, prior findings are mixed, with several studies reporting no relationships between psychopathy and anxiety, and others suggesting negative relationships for the affective, interpersonal aspects of the disorder and positive relationships for the antisocial behavior dimension. To examine whether psychopathy dimensions are associated with contemporary measures of anxiety, the Anxiety Sensitivity Index and State Trait Anxiety Inventory-Trait scale were administered to 157 male inmates. Participants also completed the MMPI-derived Welsh Anxiety Scale (WAS), commonly used in psychopathy studies. Analyses provide no evidence for a negative relationship between psychopathy's affective, interpersonal factor and anxiety sensitivity after controlling for trait anxiety. Trait anxiety and WAS scores were positively associated with the antisocial behavior dimension of psychopathy. Findings do replicate prior relationships between the WAS and psychopathy, suggesting the WAS may measure aspects of negative affectivity that differ from anxiety.

Adolescent↗

PubMed2004

Psychopathy, IQ, and violence in European American and African American county jail inmates.

The accuracy of the prediction of criminal violence may be improved by combining psychopathy with other variables that have been found to predict violence. Research has suggested that assessing intelligence (i.e., IQ) as well as psychopathy improves the accuracy of violence prediction. In the present study, the authors tested this hypothesis by using a contemporary measure of psychopathy, the Psychopathy Checklist--Revised (R. D. Hare, 2003), in a sample of 326 European American and 348 African American male offenders. The postdictive power of psychopathy was evident for both ethnic groups and robust across most changes in the operationalization of violence and the analysis conducted, whereas the postdictive power of IQ was not. No Psychopathy x IQ interactions were identified. Implications of these results for violence prediction are discussed.

Adult↗