689 research outputs found
Size and Distribution of Resting Eggs in a Natural Population of the Rotifer Brachionus plicatilis
Resting eggs of the rotifer Brachionus plicatilis were collected from the sediments of a brackish-water pond near Tampa, Florida. These core samples were examined for resting egg density and size. Resting egg density decreased exponentially from the surface down to 7 cm in the sediments at all stations, with depth in the sediments accounting for 42.3% of the total variance. The maximum resting egg density recorded was 194 RE/cm3 with no significant differences in density among stations. Resting eggs were found to be significantly larger in the top 2 cm of sediment than resting eggs from deeper in the sediments. These data are discussed with regard to other work on resting egg densities in natural populations. Hypotheses are offered to explain the observed decrease in resting egg size with depth in sediments
Size and Distribution of Resting Eggs in a Natural Population of the Rotifer Brachionus plicatilis
Resting eggs of the rotifer Brachionus plicatilis were collected from the sediments of a brackish-water pond near Tampa, Florida. These core samples were examined for resting egg density and size. Resting egg density decreased exponentially from the surface down to 7 cm in the sediments at all stations, with depth in the sediments accounting for 42.3% of the total variance. The maximum resting egg density recorded was 194 RE/cm3 with no significant differences in density among stations. Resting eggs were found to be significantly larger in the top 2 cm of sediment than resting eggs from deeper in the sediments. These data are discussed with regard to other work on resting egg densities in natural populations. Hypotheses are offered to explain the observed decrease in resting egg size with depth in sediments
Video feedback intervention for cognitively impaired older drivers: A randomized clinical trial
Introduction: This clinical trial aimed to determine whether in-car video feedback about unsafe driving events (UDE) to cognitively impaired older drivers and family members leads to a reduction in such driving behaviors.
Methods: We randomized 51 cognitively impaired older drivers to receive either (1) a weekly progress report with recommendations and access to their videos, or (2) video monitoring alone without feedback over 3 months.
Results: UDE frequency/1000 miles was reduced by 12% in feedback (rate ratio [RR] = 0.88, 95% confidence interval [CI] = .58-1.34), while remaining constant with only monitoring (RR = 1.01, 95% CI = .68-1.51). UDE severity/1000 miles was reduced by 37% in feedback (RR = 0.63, 95% CI = .31-1.27), but increased by 40% in monitoring (RR = 1.40, 95% CI = .68-2.90). Cognitive impairment moderated intervention effects (
Discussion: Results suggest the potential to improve driving safety among mild cognitively impaired older drivers using a behavior modification approach aimed at problem behaviors detected in their natural driving environment
Price Discovery and the Accuracy of Consolidated Data Feeds in the U.S. Equity Markets
Both the scientific community and the popular press have paid much attention
to the speed of the Securities Information Processor, the data feed
consolidating all trades and quotes across the US stock market. Rather than the
speed of the Securities Information Processor, or SIP, we focus here on its
accuracy. Relying on Trade and Quote data, we provide various measures of SIP
latency relative to high-speed data feeds between exchanges, known as direct
feeds. We use first differences to highlight not only the divergence between
the direct feeds and the SIP, but also the fundamental inaccuracy of the SIP.
We find that as many as 60 percent or more of trades are reported out of
sequence for stocks with high trade volume, therefore skewing simple measures
such as returns. While not yet definitive, this analysis supports our
preliminary conclusion that the underlying infrastructure of the SIP is
currently unable to keep pace with the trading activity in today's stock
market.Comment: 18 pages, 20 figures, 2 table
Trauma Team Activation for Geriatric Trauma at a Level II Trauma Center: Are the Elderly Under-triaged?
Abstract
Geriatric patients often sustain life-threatening injuries from minor trauma. A growing body of research suggests that these patients are often under-triaged in the emergency setting.The purpose of this research was to evaluate whether or not geriatric trauma patients are under-triaged at a community based level II trauma center.
1434 trauma patients over the age of 65 presenting from 2010-2015 were retrospectively reviewed from the Cabell Huntington Hospital trauma registry and analyzed for age, gender, arrival type, ED response, Glasgow Coma Scale (GCS), Injury Severity Score (ISS), injury cause, ICD-9 diagnosis codes, and mortality. Under-triage and over-triage rates were determined using the Cribari method (under-triage = ISS ≥ 16 without full trauma team activation [TTA]; Over-triage = ISS ≤ 15 with full TTA).
The under-triage rate was 9.5% (132/1393) with the majority of under-triaged patients having head trauma (n=423). There were 371 head trauma patients with a recorded GCS and analysis shows those with a GCS ≥ 13 had a 1.2% mortality risk (n=326; ISS 10.2), but that risk drastically increases to 60% with GSC ≤ 12 (n=45; ISS 21.5). Of the 45 patients with GSC ≤ 12, only 4% had priority 1 TTA using the current protocol (2/45).
The American College of Surgeons-Committee of Trauma (ACS-COT) recommends an acceptable under-triage rate of \u3c 5%. In order to improve geriatric care and reduce under-triage rates, we recommend that an age-based criteria be added to our TTA protocol at our community based Level II trauma center: priority 1 TTA for all patients 65 years or older sustaining head trauma with a GCS ≤ 12 or suspicion of intracranial hemorrhage
Behavioral Responses of Pacific Lamprey to Alarm Cues
Pacific lamprey (Entosphenus tridentatus), an anadromous ectoparasite, faces several challenges during adult migration to spawning grounds. Developingmethods to address these challenges is critical to the success of ongoing conservation efforts. The challenges are diverse, and include anthropogenic alterations to the ecosystem resulting in loss of habitat, impassable barriers such as dams, climate change impacts, and altered predator fields. We conducted a behavioral study to understand how adult migrating Pacific lamprey respond to potential alarm cues: White Sturgeon (Acipenser transmontanus), human saliva, decayed Pacific lamprey, and river otter (Lontra canadensis). Research has shown that some species of lamprey can be guided to a location using odors and similar cues may be useful as a management tool for Pacific lamprey. Experiments were conducted over 2 nights and measured the number of entries (count) and duration of time spent (occupancy) by adult lamprey in each arm of a two-choice maze. During the first night, no odor was added to test for selection bias between arms. During the second night odor was added to one arm of the maze. Contrary to expectations, lamprey were significantly attracted to the river otter odor in both count and occupancy. No significant differences were found in the response of lamprey to the other three odors. Results from this study indicate that Pacific lamprey do respond to some odors; however, additional tests are necessary to better identify the types of odors and concentrations that elicit a repeatable response
Evaluation of naturalistic driving behavior using in-vehicle monitoring technology in preclinical and early Alzheimer\u27s disease
Cognitive impairment is a significant risk factor for hazardous driving among older drivers with Alzheimer\u27s dementia, but little is known about how the driving behavior of mildly symptomatic compares with those in the preclinical, asymptomatic phase of Alzheimer\u27s disease (AD). This study utilized two in-car technologies to characterize driving behavior in symptomatic and preclinical AD. The goals of this pilot study were to (1) describe unsafe driving behaviors in individuals with symptomatic early AD using G-force triggered video capture and (2) compare the driving habits of these symptomatic AD drivers to two groups of cognitively normal drivers, those with and those without evidence of cerebral amyloidosis (CN/A+ and CN/A-) using a global positioning system (GPS) datalogger. Thirty-three drivers (aged 60+ years) were studied over 3 months. G-force triggered video events captured instances of near-misses/collisions, traffic violations, risky driver conduct, and driving fundamentals. GPS data were sampled every 30 s and all instances of speeding, hard braking, and sudden acceleration were recorded. For the early AD participants, video capture identified driving unbelted, late response, driving too fast for conditions, traffic violations, poor judgment, and not scanning intersections as the most frequently occurring safety errors. When evaluating driving using the GPS datalogger, hard breaking events occurred most frequently on a per trip basis across all three groups. The CN/A+ group had the lowest event rate across all three event types with lower instances of speeding. Slower psychomotor speed (Trail Making Part A) was associated with fewer speeding events, more hard acceleration events, and more overall events. GPS tracked instances of speeding were correlated with total number of video-captured near-collisions/collisions and driving fundamentals. Results demonstrate the utility of electronic monitoring to identify potentially unsafe driving events in symptomatic and preclinical AD. Results suggest that drivers with preclinical AD may compensate for early, subtle cognitive changes by driving more slowly and cautiously than healthy older drivers or those with cognitive impairment. Self-regulatory changes in driving behavior appear to occur in the preclinical phase of AD, but safety concerns may not arise until symptoms of cognitive impairment emerge and the ability to self-monitor declines
Elevated Temperature, Residual Compressive Strength of Impact-Damaged Sandwich Structure Manufactured Out-of-Autoclave
Several 1/16th-scale curved sandwich composite panel sections of a 10 m diameter barrel were fabricated to demonstrate the manufacturability of large-scale curved sections using minimum gauge, [+60/-60/0]s, toughened epoxy composite facesheets co-cured with low density (50 kilograms per cubic meters) aluminum honeycomb core. One of these panels was fabricated out of autoclave (OoA) by the vacuum bag oven (VBO) process using Cycom(Registered Trademark) T40-800b/5320-1 prepreg system while another panel with the same lay-up and dimensions was fabricated using the autoclave-cure, toughened epoxy prepreg system Cycom(Registered Trademark) IM7/977-3. The resulting 2.44 m x 2 m curved panels were investigated by non-destructive evaluation (NDE) at NASA Langley Research Center (NASA LaRC) to determine initial fabrication quality and then cut into smaller coupons for elevated temperature wet (ETW) mechanical property characterization. Mechanical property characterization of the sandwich coupons was conducted including edge-wise compression (EWC), and compression-after-impact (CAI) at conditions ranging from 25 C/dry to 150 C/wet. The details and results of this characterization effort are presented in this paper
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