2,242 research outputs found
Airborne assault on corregidor: a study in weather, terrain, and cultural landscapes
In many ways, military forces using advanced technologies have been able to overcome a number of the inherent and traditional challenges posed by physical geography. However, geography continues to play a significant role in military planning and operations in two areas that have received little attention in the literature, namely airborne operations and the cultural landscape. This case study sought to contribute to these discussions by analysing the American operation to seize Corregidor Island in February 1945. As a primarily airborne assault, the operation was heavily contingent on weather, but also on terrain for sufficient drop zones, and the cultural landscape and terrain intelligence of the American forces proved vital in this regard. Through analysing archival military planning documents, maps, images and other primary and secondary sources, this study found that the physical terrain and enemy defences dictated the overall plan, but two features of the cultural landscape, the parade ground and golf course, were essential to the airborne operation, serving as the smallest drop zones used in World War II by US forces. While these two spaces enabled the assault, their small size, the buildings surrounding them, and the prevailing winds made this mission the most dangerous and highest jump casualty airborne operation of the war. Despite the casualties incurred by these features, the bombed-out buildings and debris on the drop zones arguably prevented even greater casualties because of the cover these provided once paratroopers were assembled on the ground. The intent of this discussion is to demonstrate how airborne operations are inherently contingent on geography and the challenges and opportunities the cultural landscape could pose during a military operation.Keywords: military geography, airborne operations, Corregidor, cultural landscape,terrain intelligenc
Could parental rules play a role in the association between short sleep and obesity in young children?
Short sleep duration is associated with obesity in young children. This study develops the hypothesis that parental rules play a role in this association. Participants were 3-year-old children and their parents, recruited at nursery schools in socioeconomically deprived and non-deprived areas of a North-East England town. Parents were interviewed to assess their use of sleep, television-viewing and dietary rules, and given diaries to document their child's sleep for 4 days/5 nights. Children were measured for height, weight, waist circumference and triceps and subscapular skinfold thicknesses. One-hundred and eight families participated (84 with complete sleep data and 96 with complete body composition data). Parental rules were significantly associated together, were associated with longer night-time sleep and were more prevalent in the non-deprived-area compared with the deprived-area group. Television-viewing and dietary rules were associated with leaner body composition. Parental rules may in part confound the association between night-time sleep duration and obesity in young children, as rules cluster together across behavioural domains and are associated with both sleep duration and body composition. This hypothesis should be tested rigorously in large representative samples
Helicase activity on DNA as a propagating front
We develop a propagating front analysis, in terms of a local probability of
zipping, for the helicase activity of opening up a double stranded DNA (dsDNA).
In a fixed-distance ensemble (conjugate to the fixed-force ensemble) the front
separates the zipped and unzipped phases of a dsDNA and a drive acts locally
around the front. Bounds from variational analysis and numerical estimates for
the speed of a helicase are obtained. Different types of helicase behaviours
can be distinguished by the nature of the drive.Comment: 5 pages, 5 eps figures; replaced by the published versio
Bundling Payment Initiatives for Total Hip and Knee Arthroplasties: Perspectives of Health Care Professionals
Background: A broad qualitative research study explored the perceptions of rehabilitation health care professionals and administrative leadership on coordination of care for rehabilitation patients who received hip or knee arthroplasties under the bundling initiative.
Method: Data was collected through the conduction of a focus group, email communication, and individual phone interviews. Researchers analyzed data collected from five administrative personnel and eight rehabilitation health care professionals who work in a facility that participates in a bundling initiative payment model.
Results: Four major themes were identified: importance of care coordination, increased efficiency and effectiveness, establishing protocols, and challenges of bundling payment.
Conclusion: These findings indicate the significance of interprofessional collaboration and communication, establishment of patient autonomy, and adherence to rehabilitation protocols with hip or knee arthroplasties
Velocity and processivity of helicase unwinding of double-stranded nucleic acids
Helicases are molecular motors which unwind double-stranded nucleic acids
(dsNA) in cells. Many helicases move with directional bias on single-stranded
(ss) nucleic acids, and couple their directional translocation to strand
separation. A model of the coupling between translocation and unwinding uses an
interaction potential to represent passive and active helicase mechanisms. A
passive helicase must wait for thermal fluctuations to open dsNA base pairs
before it can advance and inhibit NA closing. An active helicase directly
destabilizes dsNA base pairs, accelerating the opening rate. Here we extend
this model to include helicase unbinding from the nucleic-acid strand. The
helicase processivity depends on the form of the interaction potential. A
passive helicase has a mean attachment time which does not change between ss
translocation and ds unwinding, while an active helicase in general shows a
decrease in attachment time during unwinding relative to ss translocation. In
addition, we describe how helicase unwinding velocity and processivity vary if
the base-pair binding free energy is changed.Comment: To appear in special issue on molecular motors, Journal of Physics -
Condensed Matte
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