200 research outputs found
Memories are made of this: The impact of the Vietnam War on the Persian Gulf War in rural America
Thesis (B.A.) in History--University of Illinois at Urbana-Champaign, 1992.Includes bibliographical references (leaves 80-85)Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1992]. 2 microfiches (89 frames): negative.s 1992 ilu n
From Random to Regular: Variation in the Patterning of Retinal Mosaics
The various types of retinal neurons are each positioned at their respective
depths within the retina where they are believed to be assembled as orderly
mosaics, in which like-type neurons minimize proximity to one another. Two
common statistical analyses for assessing the spatial properties of retinal
mosaics include the nearest neighbor analysis, from which an index of their
"regularity" is commonly calculated, and the density recovery profile derived
from auto-correlation analysis, revealing the presence of an exclusion zone
indicative of anti-clustering. While each of the spatial statistics derived
from these analyses, the regularity index and the effective radius, can be
useful in characterizing such properties of orderly retinal mosaics, they are
rarely sufficient for conveying the natural variation in the self-spacing
behavior of different types of retinal neurons and the extent to which that
behavior generates uniform intercellular spacing across the mosaic. We consider
the strengths and limitations of different spatial statistical analyses for
assessing the patterning in retinal mosaics, highlighting a number of
misconceptions and their frequent misuse. Rather than being diagnostic criteria
for determining simply whether a population is "regular", they should be
treated as descriptive statistics that convey variation in the factors that
influence neuronal positioning. We subsequently apply multiple spatial
statistics to the analysis of eight different mosaics in the mouse retina,
demonstrating conspicuous variability in the degree of patterning present, from
essentially random to notably regular. This variability in patterning has both
a developmental as well as a functional significance, reflecting the rules
governing the positioning of different types of neurons as the architecture of
the retina is assembled (abstract truncated).Comment: 11 Figure
Three birds with one stone: Tidal wetland restoration, carbon sequestration, and enhancing resilience to rising sea levels in the Snohomish River Estuary, Washington
Recent attention has focused on exploring the carbon storage and sequestration values of tidal wetlands to mitigate greenhouse gas emissions. Efforts are now underway to develop the tools and refine the science needed to bring carbon markets to bear on tidal wetland restoration activities. Effective restoration not only maximizes carbon storage in former tidal wetlands but also, through the accumulation of organic and mineral matter, enhances these systems’ resilience to rising sea levels. To this end, this project focuses on the Snohomish River estuary of the Puget Sound, Washington, which offers a continuum of diked and un-diked wetlands including seasonal floodplains, open mudflats, mature and tidal forests, and salt marsh habitats. In addition, there is strong restoration potential in a suite of ongoing and proposed projects. We report here on the carbon storage pools, long-term sediment accretion rates (100 years), and estimated rates of carbon storage, derived from sediment cores collected at representative sites within the Snohomish estuary during the spring and summer of 2013. We found that natural wetlands (open to tidal exchange and riverine inputs) were accreting at rates that equaled or exceeded current rates of eustatic sea level rise, while formerly, or currently diked wetlands (closed to such exchanges and inputs) revealed marked evidence of subsidence. Restored sites showed evidence of both high rates of sediment accretion (1.61 cm/year) and carbon storage (352 g C/m2/year)
Patients' reports or clinicians' assessments: Which are better for prognosticating?
BACKGROUND: The Prognosis in Palliative care Scale (PiPS) predicts survival in advanced cancer patients more accurately than a doctor's or a nurse's estimate. PiPS scores are derived using observer ratings of symptom severity and performance status. The purpose of this study was to determine whether patient-rated data would provide better prognostic estimates than clinician observer ratings. PATIENTS AND METHODS: 1018 subjects with advanced cancer no longer undergoing tumour-directed therapy were recruited to a multi-centre study. Prognostic models were developed using observer ratings, patient ratings or a composite method that used patient ratings when available or else used observer ratings. The performance of the prognostic models was compared by determining the agreement between the models' predictions and the survival of study participants. RESULTS: All three approaches to model development resulted in prognostic scores that were able to differentiate between patients with a survival of 'days', 'weeks' or 'months+'. However, the observer-rated models were significantly (p<0.05) more accurate than the patient-rated models. CONCLUSIONS: A prognostic model derived using observer-rated data was more accurate at predicting survival than a similar model derived using patient self-report measures. This is clinically important because patient-rated data can be burdensome and difficult to obtain in patients with terminal illnesses
Towards understanding resprouting at the global scale
Understanding and predicting plant response to disturbance is of paramount importance in our changing world. Resprouting ability is often considered a simple qualitative trait and used in many ecological studies. Our aim is to show some of the complexities of resprouting while highlighting cautions that need be taken in using resprouting ability to predict vegetation responses across disturbance types and biomes. There are marked differences in resprouting depending on the disturbance type, and fire is often the most severe disturbance because it includes both defoliation and lethal temperatures. In the Mediterranean biome, there are differences in functional strategies to cope with water deficit between resprouters (dehydration avoiders) and nonresprouters (dehydration tolerators); however, there is little research to unambiguously extrapolate these results to other biomes. Furthermore, predictions of vegetation responses to changes in disturbance regimes require consideration not only of resprouting, but also other relevant traits (e.g. seeding, bark thickness) and the different correlations among traits observed in different biomes; models lacking these details would behave poorly at the global scale. Overall, the lessons learned from a given disturbance regime and biome (e.g. crown-fire Mediterranean ecosystems) can guide research in other ecosystems but should not be extrapolated at the global scale.This work was performed under the framework of the TREVOL projects (CGL2012-39938-C02-01 to J.G.P.) from the Spanish Government. A.L.J., R.B.P., A.V. and S.P. were supported by the following grants: IOS-1252232 (NSF), IOS-0845125 (NSF), CGL-2011-30531-CO2-02 (SURVIVE Project, Spain), ID-1120458 (Fondo Nacional de Desarrollo Científico y Tecnológico, FONDECYT, Chile), respectively
A face for all seasons:searching for context-specific leadership traits and discovering a general preference for perceived health
Previous research indicates that followers tend to contingently match particular leader qualities to evolutionarily consistent situations requiring collective action (i.e., context-specific cognitive leadership prototypes) and information processing undergoes categorization which ranks certain qualities as first-order context-general and others as second-order context-specific. To further investigate this contingent categorization phenomenon we examined the “attractiveness halo”—a first-order facial cue which significantly biases leadership preferences. While controlling for facial attractiveness, we independently manipulated the underlying facial cues of health and intelligence and then primed participants with four distinct organizational dynamics requiring leadership (i.e., competition vs. cooperation between groups and exploratory change vs. stable exploitation). It was expected that the differing requirements of the four dynamics would contingently select for relatively healthier- or intelligent-looking leaders. We found perceived facial intelligence to be a second-order context-specific trait—for instance, in times requiring a leader to address between-group cooperation—whereas perceived health is significantly preferred across all contexts (i.e., a first-order trait). The results also indicate that facial health positively affects perceived masculinity while facial intelligence negatively affects perceived masculinity, which may partially explain leader choice in some of the environmental contexts. The limitations and a number of implications regarding leadership biases are discussed
Confirmation that a specific haplotype of the dopamine transporter gene is associated with Combined-Type ADHD
Objective: The primary purpose of this study was to confirm the association of a specific haplotype of the dopamine transporter gene and attention deficit hyperactivity disorder (ADHD), which could be one source of the heterogeneity seen across published studies. Method: The authors previously reported the association of ADHD with a subgroup of chromosomes containing specific alleles of two variable-number tandem repeat polymorphisms within the 3' untranslated region and intron 8 of the dopamine transporter gene. They now report on this association in a sample of ADHD combined-type probands. Results: The original observations were confirmed, with an overall odds ratio of 1.4 across samples. Conclusions: These data challenge results of meta-analyses suggesting that dopamine transporter variation does not have an effect on the risk for ADHD, and they indicate that further investigation of functional variation in the gene is required. <br/
30-Day Mortality and Cardiopulmonary Complication Rates in Patients Undergoing Emergency Surgery with Perioperative SARS-CoV-2 Infection
INTRODUCTION AND OBJECTIVE: Continued vigilance of operative outcomes in COVID-19 patients is important given the relative novelty of the SARS-CoV-2 infection. We sought to evaluate the 30-day mortality and cardiopulmonary complication rates in patients undergoing emergency surgery with perioperative COVID-19, in comparison to a control group of medically managed COVID-19 patients that did not require a surgical intervention.
METHODS: A retrospective chart review at a single tertiary-care hospital in Michigan was undertaken. Patients who had tested positive for SARS-CoV-2 infection either 7 days before or within 30 days after surgery during March-May 2020 were included in the study (n=52). Propensity score matched (1:6) patients who had been positive for SARS CoV-2 infection during this time-period but did not undergo surgery served as controls (n=314). The primary endpoint was 30-day mortality. Secondary endpoints included cardiac and pulmonary complications. Multivariable logistic regression analyses were utilized to account for baseline differences.
RESULTS: The 30-day mortality (17.3% vs 13.1%, p=0.408) and cardiac (28.9% vs 19.1%, p=0.107) and pulmonary complication (55.8% vs 49.4%, p=0.392) rates were similar in the surgical and the non-surgical groups. Multivariable analyses confirmed that emergency surgical intervention was not associated with increased odds for any of the studied adverse events (p\u3e0.10 for all 3 endpoints).
CONCLUSIONS: Our analysis of 366 novel coronavirus patients demonstrates that patients undergoing emergency surgery with SARS-CoV-2 infection do not have an increased risk for 30-day mortality and cardiopulmonary complications compared to their counterparts that do not require surgery. The importance of this study is that an emergency intervention does not portend a poorer prognosis among patients with a confirmed SARS-CoV-2 Infection
Zero Botnets: An Observe-Pursue-Counter Approach
Adversarial Internet robots (botnets) represent a growing threat to the safe
use and stability of the Internet. Botnets can play a role in launching
adversary reconnaissance (scanning and phishing), influence operations
(upvoting), and financing operations (ransomware, market manipulation, denial
of service, spamming, and ad click fraud) while obfuscating tailored tactical
operations. Reducing the presence of botnets on the Internet, with the
aspirational target of zero, is a powerful vision for galvanizing policy
action. Setting a global goal, encouraging international cooperation, creating
incentives for improving networks, and supporting entities for botnet takedowns
are among several policies that could advance this goal. These policies raise
significant questions regarding proper authorities/access that cannot be
answered in the abstract. Systems analysis has been widely used in other
domains to achieve sufficient detail to enable these questions to be dealt with
in concrete terms. Defeating botnets using an observe-pursue-counter
architecture is analyzed, the technical feasibility is affirmed, and the
authorities/access questions are significantly narrowed. Recommended next steps
include: supporting the international botnet takedown community, expanding
network observatories, enhancing the underlying network science at scale,
conducting detailed systems analysis, and developing appropriate policy
frameworks.Comment: 26 pages, 13 figures, 2 tables, 72 references, submitted to PlosOn
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