414 research outputs found
Silicon Needle Transducer
Silicon semiconductor needle transducer to utilize piezojunction effec
Effect of Different Levels of Physical Fatigue Upon Motor Learning and Subsequent Motor Performance.
Continuity and Change in Values in Midlife: Testing the Age Stability Hypothesis
21 pagesBackground/Study Context: The “age stability” hypothesis suggests that
adults have significant continuities in values over time, whereas the “situational
influence” hypothesis suggests that change continues, especially in
response to new events and experiences. Deeply ingrained, terminal values
may be more stable than other, more instrumental, values. Less research
examines changing values than examines changing personality traits and
attitudes. Methods: Hypotheses were tested with data from A Study of Leisure
During Adulthood (ASOLDA), a 9-year panel study of middle-aged adults
(average age of 45 at the beginning of data collection). Mixed-model
regressions and descriptive statistics were used to examine changes and
stability over time in global values, measured by the List of Values (LOV),
and instrumental values related to leisure. Results: Significant correlations were found in both terminal and
instrumental values over time (autocorrelations ranging from .13 to
.23). There was no linear or curvilinear pattern of change over time.
Respondents reported a wide range of positive and negative life events
and variations over time in reflections on their life structure, but these
variations were unrelated to changes in values. Conclusion: Results support the age stability hypothesis, rather than
the situational influence hypothesis, with similar results for both terminal
and instrumental values. It is suggested that the consistent values
of respondents may have helped them weather the wide range of
often-difficult circumstances many reported experiencing. Future research
should examine this hypothesis
Development and Testing of a Short Form of the Patient Activation Measure
13 pagesObjective: The Patient Activation Measure (PAM) is a 22-item measure that assesses
patient knowledge, skill, and confidence for self-management. The measure was developed using Rasch analyses and is an interval level, unidimensional, Guttman-like
measure. The current analysis is aimed at reducing the number of items in the measure
while maintaining adequate precision.
Study Methods: We relied on an iterative use of Rasch analysis to identify items that
could be eliminated without loss of significant precision and reliability.With each item
deletion, the item scale locations were recalibrated and the person reliability evaluated
to check if and how much of a decline in precision of measurement resulted from the
deletion of the item.
Data Sources: The data used in the analysis were the same data used in the development
of the original 22-item measure. These data were collected in 2003 via a telephone
survey of 1,515 randomly selected adults.
Principal Findings: The analysis yielded a 13-item measure that has psychometric
properties similar to the original 22-item version. The scores for the 13-item measure
range in value from38.6 to 53.0 (on a theoretical 0–100 point scale). The range of values
is essentially unchanged from the original 22-item version. Subgroup analysis suggests
that there is a slight loss of precision with some subgroups.
Conclusions: The results of the analysis indicate that the shortened 13-item version is
both reliable and valid
Impact of facial conformation on canine health: Brachycephalic Obstructive Airway Syndrome
The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring
Shaping Skeletal Growth by Modular Regulatory Elements in the Bmp5 Gene
Cartilage and bone are formed into a remarkable range of shapes and sizes that underlie many anatomical adaptations to different lifestyles in vertebrates. Although the morphological blueprints for individual cartilage and bony structures must somehow be encoded in the genome, we currently know little about the detailed genomic mechanisms that direct precise growth patterns for particular bones. We have carried out large-scale enhancer surveys to identify the regulatory architecture controlling developmental expression of the mouse Bmp5 gene, which encodes a secreted signaling molecule required for normal morphology of specific skeletal features. Although Bmp5 is expressed in many skeletal precursors, different enhancers control expression in individual bones. Remarkably, we show here that different enhancers also exist for highly restricted spatial subdomains along the surface of individual skeletal structures, including ribs and nasal cartilages. Transgenic, null, and regulatory mutations confirm that these anatomy-specific sequences are sufficient to trigger local changes in skeletal morphology and are required for establishing normal growth rates on separate bone surfaces. Our findings suggest that individual bones are composite structures whose detailed growth patterns are built from many smaller lineage and gene expression domains. Individual enhancers in BMP genes provide a genomic mechanism for controlling precise growth domains in particular cartilages and bones, making it possible to separately regulate skeletal anatomy at highly specific locations in the body
THE PRESENT STATUS OF THE GERM-CELL PROBLEM IN VERTEBRATES
(i) Morphological studies relating to the origin and differentiation of the definitive germ cells in vertebrates have, as indicated, resulted in conflicting views. In many instances two or more competent investigators who have studied the same form have reached different conclusions. (2) Some contend that the germ cells are set aside from the soma during the early stages of embryonic development, and that these alone serve as the progenitors of the functional sex cells. (3) Others recognize an early differentiation of sex cells but hold that these are supplemented by others produced from the somatic epithelium of the gonad in late embryonic or post-embryonic stages. (4) Another group recognizes the early differentiated cells as germ cells but contend that these all degenerate and that the definitive ones are formed from the germinal epithelium. These degenerating germ cells are believed by certain authors to be a phylogenetic recapitulation of the condition in lower forms. (5) Finally, yet another group contends that the so-called primordial germ cells are not germ cells at all but are enlarged cells in some stage of mitosis or in some specific metabolic phase. This group believes that all germ cells are derived from the somatic cells of the germinal epithelium. (6) Experimental work supports the view that the primordial germ cells, which are recognized early, are the progenitors of the definitive sex cells. When these primordial germ cells are prevented from reaching the site of the developing gonad the individual fails to develop sex cells, although a sterile gonad and its associated structures may develop. (7) I suggest that the observed proliferation of germ cells from the germinal epithelium, reported by numerous investigators, can be interpreted in another way by a thorough study of the enlarged germ cells in relation to the epithelium. It seems probable that the cells of the epithelium, which form functional sex elements, are not and never were a part of the mesothelial covering, but are cells which were segregated early, and are merely stored in the epithelium.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74677/1/j.1469-185X.1945.tb00313.x.pd
Effects of the cannabinoid CB1 agonist ACEA on salicylate ototoxicity, hyperacusis and tinnitus in guinea pigs
Cannabinoids have been suggested as a therapeutic target for a variety of brain disorders. Despite the presence of their receptors throughout the auditory system, little is known about how cannabinoids affect auditory function. We sought to determine whether administration of arachidonyl-2′-chloroethylamide (ACEA), a highly-selective CB1 agonist, could attenuate a variety of auditory effects caused by prior administration of salicylate, and potentially treat tinnitus. We recorded cortical resting-state activity, auditory-evoked cortical activity and auditory brainstem responses (ABRs), from chronically-implanted awake guinea pigs, before and after salicylate + ACEA. Salicylate-induced reductions in click-evoked ABR amplitudes were smaller in the presence of ACEA, suggesting that the ototoxic effects of salicylate were less severe. ACEA also abolished salicylate-induced changes in cortical alpha band (6-10 Hz) oscillatory activity. However, salicylate-induced increases in cortical evoked activity (suggestive of the presence of hyperacusis) were still present with salicylate + ACEA. ACEA administered alone did not induce significant changes in either ABR amplitudes or oscillatory activity, but did increase cortical evoked potentials. Furthermore, in two separate groups of non-implanted animals, we found no evidence that ACEA could reverse behavioural identification of salicylate- or noise-induced tinnitus. Together, these data suggest that while ACEA may be potentially otoprotective, selective CB1 agonists are not effective in diminishing the presence of tinnitus or hyperacusis
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