68 research outputs found
Radiation effects on silicon second quarterly progress report, sep. 1 - nov. 30, 1964
Electron spin resonance measurements on P-doped silicon - vacancy phosphorus defec
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Assessing the stability of tree ranges and influence of disturbance in eastern US forests
Shifts in tree species ranges may occur due to global climate change, which in turn may be exacerbated
by natural disturbance events. Within the context of global climate change, developing techniques to
monitor tree range dynamics as affected by natural disturbances may enable mitigation/adaptation of
projected impacts. Using a forest inventory across the eastern U.S., the northern range margins of tree
distributions were examined by comparing differences in the 95th percentile locations of seedlings to
adults (i.e., trees) by 0.5° longitudinal bands over 5-years and by levels of disturbance (i.e., canopy gap
formation). Our results suggest that the monitoring of tree range dynamics is complicated by the limits
of forest inventory data across varying spatial/temporal scales and the diversity of tree species/environments
in the eastern U.S. The vast majority of tree and seedling latitudinal comparisons across measurement
periods and levels of disturbance in the study were not statistically different from zero (53 out of 60
comparisons). A potential skewing of ranges towards a northern limit was suggested by the stability of
northern margins of tree ranges found in this study and shifts in mean locations identified in previous
work. Only a partial influence of disturbances on tree range dynamics during the course of the 5-years
was found in this study. The results of this study underscore the importance of continued examination
of the role of disturbance in tree range dynamics and refined range monitoring techniques given future
forest extent and biodiversity implications.Keywords: Disturbance, Seedlings, Tree range retreat, Climate change, Tree species migration, Canopy gapsKeywords: Disturbance, Seedlings, Tree range retreat, Climate change, Tree species migration, Canopy gap
Anxiety and depression after prostate cancer diagnosis and treatment: 5-year follow-up
To document anxiety and depression from pretreatment till 5-year follow-up in 299 men with localized prostate cancer. To assess, if baseline scores were predictive for anxiety and depression at 1-year follow-up. Respondents completed four assessments (pretreatment, at 6 and 12 months, and at 5-year follow-up) on anxiety, depression and mental health. Respondents were subdivided according to therapy (prostatectomy or radiotherapy) and high vs low-anxiety. Pretreatment 28% of all patients were classified as ‘high-anxiety'; their average anxiety scores decreased significantly post-treatment, that is towards less anxiety. At all assessments, high-anxiety men treated by prostatectomy reported less depression than high-anxiety men treated by radiotherapy. Of men treated by radiotherapy, 27% reported clinical significant levels of depression while 20% is expected in a general population. The improvement in mental health at 6-months follow-up was statistically significant and clinically meaningful in all respondent groups. Sensitivity of anxiety at baseline as a screening tool was 71% for anxiety and 60% for symptoms of depression. We recommend clinicians to attempt early detection of patients at risk of high levels of anxiety and depression after prostate cancer diagnosis since prevalence is high. STAI-State can be a useful screening tool but needs further development
In vitro phosphorylation as tool for modification of silk and keratin fibrous materials
An overview is given of the recent work on in vitro enzymatic phosphorylation of silk fibroin and human hair keratin. Opposing to many chemical "conventional" approaches, enzymatic phosphorylation is in fact a mild reaction and the treatment falls within "green chemistry" approach. Silk and keratin are not phosphorylated in vivo, but in vitro. This enzyme-driven modification is a major technological breakthrough. Harsh chemical chemicals are avoided, and mild conditions make enzymatic phosphorylation a real "green chemistry" approach. The current communication presents a novel approach stating that enzyme phosphorylation may be used as a tool to modify the surface charge of biocompatible materials such as keratin and silk
Variability in the analysis of a single neuroimaging dataset by many teams
Data analysis workflows in many scientific domains have become increasingly complex and flexible. To assess the impact of this flexibility on functional magnetic resonance imaging (fMRI) results, the same dataset was independently analyzed by 70 teams, testing nine ex-ante hypotheses. The flexibility of analytic approaches is exemplified by the fact that no two teams chose identical workflows to analyze the data. This flexibility resulted in sizeable variation in hypothesis test results, even for teams whose statistical maps were highly correlated at intermediate stages of their analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Importantly, meta-analytic approaches that aggregated information across teams yielded significant consensus in activated regions across teams. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset. Our findings show that analytic flexibility can have substantial effects on scientific conclusions, and demonstrate factors related to variability in fMRI. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for multiple analyses of the same data. Potential approaches to mitigate issues related to analytical variability are discussed
Variability in the analysis of a single neuroimaging dataset by many teams
Data analysis workflows in many scientific domains have become increasingly complex and flexible. To assess the impact of this flexibility on functional magnetic resonance imaging (fMRI) results, the same dataset was independently analyzed by 70 teams, testing nine ex-ante hypotheses. The flexibility of analytic approaches is exemplified by the fact that no two teams chose identical workflows to analyze the data. This flexibility resulted in sizeable variation in hypothesis test results, even for teams whose statistical maps were highly correlated at intermediate stages of their analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Importantly, meta-analytic approaches that aggregated information across teams yielded significant consensus in activated regions across teams. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset. Our findings show that analytic flexibility can have substantial effects on scientific conclusions, and demonstrate factors related to variability in fMRI. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for multiple analyses of the same data. Potential approaches to mitigate issues related to analytical variability are discussed
Chylous Ascites in a Patient with HIV/AIDS: A Late Complication of Mycobacterium avium Complex-Immune Reconstitution Inflammatory Syndrome
Chylous ascites is very rare in HIV/AIDS and its association with Mycobacterium avium complex-immune reconstitution inflammatory syndrome (MAC-IRIS) has been rarely reported. Here, we report a case of a young African-American male who developed chylous ascites as a late sequela to immune reconstitution inflammatory syndrome while on treatment for MAC. Antiretroviral drug-naive patients who start HAART in close proximity to the diagnosis of an opportunistic infection and have a rapid decline in HIV RNA level should be monitored for development of IRIS. Although the long term prognosis is poor, early diagnosis and treatment help to improve quality of life
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