230 research outputs found
A Market for Success: How a Robust Service Provider Market Can Help Community Colleges Improve Student Completion
Outlines how external service providers can help community colleges enhance institutional redesign, use of data, student services and supports, and faculty development in order to remove barriers to completion, increase efficiency, and improve outcomes
Crew factors in flight operations 6: Psychophysiological responses to helicopter operations
Thirty-two helicopter pilots were studied before, during, and after 4-5 day trips providing support services from Aberdeen, Scotland, to rigs in the North Sea oil fields. Early on-duty times obliged subjects to wake up 1.5 hours earlier on trip days than on pretrip days. Consequently, they slept nearly an hour less per night on trips. They reported more fatigue on post-trip days than on pretrip days, suggesting a cumulative effect of duty-related activities and sleep loss. Fatigue and negative affect were higher, and activation lower, by the end of trip days than by the end of pretrip days. The earlier a subject went on duty, the lower his activation by the end of the day. Caffeine consumption increased 42 percent on trip days. The incidence of headache doubled, of back pain increased twelve fold, and of burning eyes quadrupled. In the aircraft studied, thermal discomfort and high vibration levels were common. The longer pilots remained on duty, the more negative their mood became
Crew Factors in Flight Operations 7: Psychophysiological Responses to Overnight Cargo Operations
To document the psychophysiological effects of flying overnight cargo operations, 41 B-727 crew members (average age 38 yr) were monitored before, during, and after one of two typical 8-day trip patterns. During daytime layovers, the average sleep episode was 3 hr (41%) shorter than nighttime sleeps and was rated as lighter, less restorative, and poorer overall. Sleep was frequently split into several episodes and totaled 1.2 hr less per 24 hr than on pretrip days. Each trip pattern included a night off, which was an effective countermeasure against the accumulating sleep debt. The organization of sleep during daytime layovers reflected the interaction of duty timing with circadian physiology. The circadian temperature rhythm did not adapt completely to the inverted wake-rest schedule on duty days, being delayed by about 3 hr. Highest subjective fatigue and lowest activation occurred around the time of the temperature minimum. On duty days, reports of headaches increased by 400%, of congested nose by 200%, and of burning eyes by 900%. Crew members also reported eating more snacks. Compared with daytime short-haul air-transport operations, the overnight cargo trips included fewer duty and flight hours, and had longer layovers. Overnight cargo crews also averaged 5.4 yr younger than their daytime short-haul counterparts. On trips, both groups lost a comparable amount of sleep per 24 hr, but the overnight cargo crews had shorter individual sleep episodes and more broken sleep. These data clearly demonstrate that overnight cargo operations, like other night work, involve physiological disruption not found in comparable daytime operations
âItâs like equality now; itâs not as if itâs the old daysâ: an investigation into gender identity development and football participation of adolescent girls
This article explores the influence participating in football has on the development of adolescent girlsâ gender identity, an area which currently lacks academic attention. Data were taken from an ethnographic study with a group of adolescent girls and boys and compared to Jeanesâ research. A social constructionist framework was deployed with links to both critical theory and feminist literature. Qualitative and participatory methods were used to fully engage with the complex issue of gender identity. The girls within this study were aware of the normative gender expectations linked to âbeing a femaleâ but did not find this restrictive. The girls moved between many changing identities and organised their âweb of selvesâ accordingly. The apparent need to measure success by the parameters of male standards created a barrier to girlsâ identity development
Fabrication and in vitro testing of polymeric delivery system for condensed DNA
Polyethylenimine (PEI) was combined with plasmid DNA and freeze dried following the addition of sucrose as a lyoprotectant and pore-forming agent. Freeze-dried PEI DNA condensates were dry mixed with granular polylactideglycolic acid (PLGA) then compression molded and sponged to encapsulated PEI DNA. A measurement of the elastic modulus indicated that 91 wt% sucrose substituted for 95 wt% sodium chloride as a porogen, resulting in PLGA sponges with a mechanical modulus of 100 kPa. The PEI DNA was retained (80%) within PLGA sponges prepared with sucrose during the leaching and subsequent 2-week release studies, whereas sodium chloride PLGA sponges caused the premature release (100%) of PEI DNA within 2 days. In vitro gene transfer studies with PEI DNA PLGA sponges established that adherent and infiltrating fibroblasts expressed reporter gene for 15 days compared with the short, 3-day expression mediated by direct gene of PEI DNA on cells in culture. The results demonstrate an approach to encapsulate condensed DNA in a PLGA sponge for the purpose of retaining DNA within the matrices and creating efficient gene transfer during tissue engineering. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 1384â1392, 2003Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34432/1/20036_ftp.pd
Crew factors in flight operations. 8: Factors influencing sleep timing and subjective sleep quality in commercial long-haul flight crews
How flight crews organize their sleep during layovers on long-haul trips is documented. Additionally, environmental and physiological constraints on sleep are examined. In the trips studied, duty periods averaging 10.3 hr alternated with layovers averaging 24.8 hr, which typically included two subject-defined sleep episodes. The circadian system had a greater influence on the timing and duration of first-sleeps than second-sleeps. There was also a preference for sleeping during the local night. The time of falling asleep for second-sleeps was related primarily to the amount of sleep already obtained in the layover, and their duration depended on the amount of time remaining in the layover. For both first- and second-sleeps, sleep durations were longer when subjects fell asleep earlier with respect to the minimum of the circadian temperature cycle. Naps reported during layovers and on the flight deck may be a useful strategy for reducing cumulative sleep loss. The circadian system was not able to synchronize with the rapid series of time-zone shifts. The sleep/wake cycle was forced to adopt a period different from that of the circadian system. Flight and duty time regulations are a means of ensuring that reasonable minimum rest periods are provided. This study clearly documents that there are physiologically and environmentally determined preferred sleep times within a layover. The actual time available for sleep is thus less than the scheduled rest period
Subânanometer thick gold nanosheets as highly efficient catalysts
2D metal nanomaterials offer exciting prospects in terms of their properties and functions. However, the ambient aqueous synthesis of atomicallyâthin, 2D metallic nanomaterials represents a significant challenge. Herein, freestanding and atomicallyâthin gold nanosheets with a thickness of only 0.47 nm (two atomic layers thick) are synthesized via a oneâstep aqueous approach at 20 °C, using methyl orange as a confining agent. Owing to the high surfaceâareaâtoâvolume ratio, abundance of unsaturated atoms exposed on the surface and large interfacial areas arising from their ultrathin 2D nature, the asâprepared Au nanosheets demonstrate excellent catalysis performance in the model reaction of 4ânitrophenol reduction, and remarkable peroxidaseâmimicking activity, which enables a highly sensitive colorimetric sensing of H2O2 with a detection limit of 0.11 Ă 10â6 m. This work represents the first fabrication of freestanding 2D gold with a subânanometer thickness, opens up an innovative pathway toward atomicallyâthin metal nanomaterials that can serve as model systems for inspiring fundamental advances in materials science, and holds potential across a wide region of applications
Subânanometer thick gold nanosheets: subânanometer thick gold nanosheets as highly efficient catalysts (Adv. Sci. 21/2019)
In article number 1900911, Stephen D. Evans and coâworkers develop an ambient aqueous synthesis for preparing atomicallyâthin gold nanosheets (termed gold nanoseaweed, AuNSW, because of its morphology, color and aqueous growth). These AuNSWs represent the first freeâstanding 2D gold with a subânanometer thickness (0.47 nm, e.g., two atomic layers thick), and exhibit excellent catalysis performance in the model reaction of 4ânitrophenol reduction, as well as remarkable peroxidaseâmimicking activity
- âŠ