982 research outputs found
IMPACT CHARACTERISTICS OF TWO TYPES OF HOCKEY ARENA BOARDS
The purpose of this study was to investigate the energy absorption and energy transmission characteristics of two different types of ice hockey arena boards when impacted at both shoulder height and hip height. Traditional or standard boards were compared to a new, "softer", and theoretically more energy absorbent, type of boards. A pendulum system was designed to provide a method of impacting both the "glass" and "boards" sections with varying masses and at varying velocities. A Tri-axial accelerometer and a displacement transducer were attached to the pendulum mass to allow direct measurement of acceleration, velocity, and displacement during impact. Using these variables, forces and energies could be calculated. The results of this study indicated that standard arena boards returned 73 % more peak force per joule of initial energy than the new softer boards. The pooled data over conditions also indicated that the standard boards were 136 % stiffer than the new boards and that the new, softer boards absorbed 23 % more impact energy than their traditional counterparts. These results have particular relevance to the problem of injuries in the sport of ice hockey. It would appear that the softer boards are significantly better at absorbing impact energy and reducing peak forces, thus reducing the risk of injury on impact
Socially situated perfectionism in a high school choir
School choirs, bands, and orchestras in the United States have long been guided by exacting standards of performance practice that require high levels of technical proficiency. Such ensembles are also socially situated, requiring interpersonal interaction as participants work toward achieving a shared set of goals. These factors could combine to exacerbate individuals’ perceived pressure to meet goals. Hewitt and Flett (1991) called this pressure socially situated perfectionism. Some researchers have argued that perfectionism might be tempered or exacerbated in certain environments (Damien et al., 2014; Dunn et al., 2012; Flett & Hewitt, 2002; Hewitt et al., 2003; McArdle, 2010; Mouratidis & Michou, 2011). The purpose of this study was to investigate the experiences of perfectionistic students, particularly their perceptions of expectations, self-worth, and acceptance associated with socially situated perfectionism, in a high school choral classroom. In order to carry out this examination, a multiple case study methodology was employed; three high school students and their choir director were interviewed and observed in choral rehearsals, with students also asked to journal about their experiences. To varying degrees across cases and within cases, participants displayed behaviors that aligned with descriptions of socially situated perfectionism outlined by Hewitt and Flett (1991). The presence of these behaviors suggests that perfectionism may play a role in their music making. It appears likely that the choral classroom environment, as facilitated by the instructor and including instructor critique/feedback as well as peer interactions, merits further study for its potential role in abating or exacerbating perfectionistic tendencies in certain individuals
Interface Tension in Quenched QCD
We calculate the tension of the interface between the confined and
deconfined phases by the histogram method in SU(3) lattice gauge theory for
temporal extents of 4 and 6 using the recent high-statistics data by QCDPAX
collaboration. The results are and 0.0218(33) for
and 6, respectively. The ratio shows a scaling violation
similar to that already observed for the latent heat \latent. However, we
find that the physically interesting dimensionless combinations
(\sigma^{3}/\latent^2 T)^{1/2} and \sigma T/ \latent scale within the
statistical errors.Comment: 13 pages with 2 PostScript figures, LaTeX, CERN-TH.6798/93,
AZPH-TH/93-04, UTHEP-25
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Multiple Constructs and the Effects of Accommodations on Standardized Test Scores for Students with Disabilities
Students with disabilities frequently use accommodations to participate in large-scale, standardized assessments. Accommodations can include changes to the administration of the test, such as extended time, changes to the test items, such as read aloud, or changes to the student’s response, such as the use of a scribe. Some accommodations or modifications risk changing the difficulty of the test items or decreasing the validity of how test scores are interpreted. Questions regarding the validity of accommodated tests are heightened when scores are used in high-stakes decisions such as grade promotion, graduation, teacher merit pay, or other accountability initiatives. The purpose of this article is to review existing literature on multiple constructs that affect validity of interpretations of accommodated assessment scores. Research on assessment accommodations continues to grow but offers few conclusive findings on whether they facilitate fair and accurate measurement of student knowledge and skill. The validity of an accommodated score appears to vary depending on several factors such as student characteristics, test characteristics, and the accommodations themselves. A multiple construct approach may facilitate more accurate evaluations of the effects of accommodated test scores Accessed 12,923 times on https://pareonline.net from October 19, 2009 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right
Spatial Intensity Distribution Analysis Reveals Abnormal Oligomerization of Proteins in Single Cells
AbstractKnowledge of membrane receptor organization is essential for understanding the initial steps in cell signaling and trafficking mechanisms, but quantitative analysis of receptor interactions at the single-cell level and in different cellular compartments has remained highly challenging. To achieve this, we apply a quantitative image analysis technique—spatial intensity distribution analysis (SpIDA)—that can measure fluorescent particle concentrations and oligomerization states within different subcellular compartments in live cells. An important technical challenge faced by fluorescence microscopy-based measurement of oligomerization is the fidelity of receptor labeling. In practice, imperfect labeling biases the distribution of oligomeric states measured within an aggregated system. We extend SpIDA to enable analysis of high-order oligomers from fluorescence microscopy images, by including a probability weighted correction algorithm for nonemitting labels. We demonstrated that this fraction of nonemitting probes could be estimated in single cells using SpIDA measurements on model systems with known oligomerization state. Previously, this artifact was measured using single-step photobleaching. This approach was validated using computer-simulated data and the imperfect labeling was quantified in cells with ion channels of known oligomer subunit count. It was then applied to quantify the oligomerization states in different cell compartments of the proteolipid protein (PLP) expressed in COS-7 cells. Expression of a mutant PLP linked to impaired trafficking resulted in the detection of PLP tetramers that persist in the endoplasmic reticulum, while no difference was measured at the membrane between the distributions of wild-type and mutated PLPs. Our results demonstrate that SpIDA allows measurement of protein oligomerization in different compartments of intact cells, even when fractional mislabeling occurs as well as photobleaching during the imaging process, and reveals insights into the mechanism underlying impaired trafficking of PLP
Trials
BACKGROUND: An international workshop on population health intervention research (PHIR) was organized to foster exchanges between experts from different disciplines and different fields. This paper aims to summarize the discussions around some of the issues addressed: (1) the place of theories in PHIR, (2) why theories can be useful, and (3) how to choose and use the most relevant of them in evaluating PHIR. METHODS: The workshop included formal presentations by participants and moderated discussions. An oral synthesis was produced by a rapporteur to validate, through an expert consensus, the key points of the discussion and the recommendations. All discussions were recorded and have been fully transcribed. RESULTS: The following recommendations were generated through a consensus in the workshop discussions: (i) The evaluation of interventions, like their development, could be improved through better use of theory. (ii) The referenced theory and framework must be clarified. (iii) An intervention theory should be developed by a partnership of researchers and practitioners. (iv) More use of social theory is recommended. (v) Frameworks and a common language are helpful in selecting and communicating a theory. (vi) Better reporting of interventions and theories is needed. CONCLUSION: Theory-driven interventions and evaluations are key in PHIR as they facilitate the understanding of mechanisms of change. There are many challenges in developing the most appropriate theories for interventions and evaluations. With the wealth of information now being generated, this subject is of increasing importance at many levels, including for public health policy. It is, therefore, timely to consider how to build on the experiences of many different disciplines to enable the development of better theories and facilitate evidence-based decisions
Re-weighting of somatosensory inputs from the foot and the ankle for controlling posture during quiet standing following trunk extensor muscles fatigue
The present study focused on the effects of trunk extensor muscles fatigue on
postural control during quiet standing under different somatosensory conditions
from the foot and the ankle. With this aim, 20 young healthy adults were asked
to stand as immobile as possible in two conditions of No fatigue and Fatigue of
trunk extensor muscles. In Experiment 1 (n = 10), somatosensation from the foot
and the ankle was degraded by standing on a foam surface. In Experiment 2 (n =
10), somatosensation from the foot and ankle was facilitated through the
increased cutaneous feedback at the foot and ankle provided by strips of
athletic tape applied across both ankle joints. The centre of foot pressure
displacements (CoP) were recorded using a force platform. The results showed
that (1) trunk extensor muscles fatigue increased CoP displacements under
normal somatosensatory conditions (Experiment 1 and Experiment 2), (2) this
destabilizing effect was exacerbated when somatosensation from the foot and the
ankle was degraded (Experiment 1), and (3) this destabilizing effect was
mitigated when somatosensation from the foot and the ankle was facilitated
(Experiment 2). Altogether, the present findings evidenced re-weighting of
sensory cues for controlling posture during quiet standing following trunk
extensor muscles fatigue by increasing the reliance on the somatosensory inputs
from the foot and the ankle. This could have implications in clinical and
rehabilitative areas
Quantitative evaluation of neuropharmacological trials
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116906/1/cpt1974153229.pd
Use of fecal calprotectin as marker of disease activity in patients under maintenance treatment with infliximab for ulcerative colitis
The quantum structure of black holes
We give an elementary review of black holes in string theory. We discuss
black hole entropy from string microstates and Hawking radiation from these
states. We then review the structure of 2-charge microstates, and explore how
`fractionation' can lead to quantum effects over macroscopic length scales of
order the horizon radius.Comment: Review article, 58 pages, 2 figures; references added, note about
topics covere
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