214 research outputs found
The effect of illumination on the time to, and pupil area of, maximum mydriasis
This study was designed to evaluate the mydriatic effects of patients being dilated under differing illumination conditions. Twenty subjects, ten females and ten males had their pupils dilated under darkened conditions and under normal illumination to determine if there would be a difference in the rate of mydriasis, or overall pupil size at the point of maximum dilation. Iris color and gender were separately evaluated factors in dilation results. Subjects were dilated using one drop each of tetracaine 1%, phenylephrine HCI 2.5%, and tropicamide 1%. Pupil diameter was periodically measured using a Cogan\u27s pupilometer starting 6 minutes after drop instillation. Measurements with the pupilometer were taken at two minute intervals throughout the 30 minute test period. The final measurement 33 minutes after instillation of the dilating drops was taken with a biomicroscope reticule, both horizontal and vertical diameters were measured. No significant differences were seen between gender, iris color, or illumination type on the rate of maximum mydriasis. However, the relative pupil area was significantly greater following dilation under normal illumination conditions
The effect of illumination on the time to, and pupil area of, maximum mydriasis
This study was designed to evaluate the mydriatic effects of patients being dilated under differing illumination conditions. Twenty subjects, 1 a females and 1 a males, had their pupils dilated under darkened conditions and under normal illumination to determine if there would be a difference in the rate of mydriasis or overall pupil size at the point of maximum dilation. Iris colour and gender were separately evaluated factors in dilation results. Subjects were dilated using one drop each of 1% tetracaine, 2.5% phenylephrine HCI and 1% tropicamide. Pupil diameter was periodically measured using a Cogan pupillometer starting 6 minutes after drop instillation. Measurements with the pupillometer were taken at two-minute intervals throughout the 3 a-minute test period. The final measurement 33 minutes after instillation of the dilating drops was taken with a biomicroscope reticule; both horizontal and vertical diameters were measured. No Significant differences were seen between gender, iris colour and illumination type on the rate of maximum mydriasis. However, the relative pupil area was significantly greater following dilation under normal illumination conditions
Formation of oriented particles in an amorphous host: ZnS nanocrystals in silicon
Processes for incorporating randomly oriented crystalline precipitates in an amorphous host can be traced back to the 17th century when Cassius produced âgold rubyâ glass. In this glass, octahedral colloidal precipitates of gold scatter light by the Mie process to produce a deep red color. In contrast to gold ruby glass, we describe a type of material in which the crystalline precipitates are crystallographically aligned in a coherent mannerâeven though they are dispersed in an amorphous matrix. Ion implantation and thermal processing are first used to form zinc sulfide nanocrystals that are coherently oriented with respect to a crystalline Si host. The Si is then amorphized by ion irradiation leaving the highly radiation-resistant ZnS precipitates in an aligned crystalline state. The process is anticipated to find applications in the creation of surfaces with unique optoelectronic properties. Š 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69678/2/APPLAB-74-5-697-1.pd
Role of viral hemagglutinin glycosylation in anti-influenza activities of recombinant surfactant protein D
<p>Abstract</p> <p>Background</p> <p>Surfactant protein D (SP-D) plays an important role in innate defense against influenza A viruses (IAVs) and other pathogens.</p> <p>Methods</p> <p>We tested antiviral activities of recombinant human SP-D against a panel of IAV strains that vary in glycosylation sites on their hemagglutinin (HA). For these experiments a recombinant version of human SP-D of the Met11, Ala160 genotype was used after it was characterized biochemically and structurally.</p> <p>Results</p> <p>Oligosaccharides at amino acid 165 on the HA in the H3N2 subtype and 104 in the H1N1 subtype are absent in collectin-resistant strains developed <it>in vitro </it>and are important for mediating antiviral activity of SP-D; however, other glycans on the HA of these viral subtypes also are involved in inhibition by SP-D. H3N2 strains obtained shortly after introduction into the human population were largely resistant to SP-D, despite having the glycan at 165. H3N2 strains have become steadily more sensitive to SP-D over time in the human population, in association with addition of other glycans to the head region of the HA. In contrast, H1N1 strains were most sensitive in the 1970sâ1980s and more recent strains have become less sensitive, despite retaining the glycan at 104. Two H5N1 strains were also resistant to inhibition by SP-D. By comparing sites of glycan attachment on sensitive vs. resistant strains, specific glycan sites on the head domain of the HA are implicated as important for inhibition by SP-D. Molecular modeling of the glycan attachment sites on HA and the carbohydrate recognition domain of SPD are consistent with these observations.</p> <p>Conclusion</p> <p>Inhibition by SP-D correlates with presence of several glycan attachment sites on the HA. Pandemic and avian strains appear to lack susceptibility to SP-D and this could be a contributory factor to their virulence.</p
Recommended from our members
Patterns of woodboring beetle activity following fires and bark beetle outbreaks in montane forests of California, USA
Increasingly frequent and severe drought in the western United States has contributed to more frequent and severe wildfires, longer fire seasons, and more frequent bark beetle outbreaks that kill large numbers of trees. Climate change is expected to perpetuate these trends, especially in montane ecosystems, calling for improved strategies for managing Western forests and conserving the wildlife that they support. Woodboring beetles (e.g., Buprestidae and Cerambycidae) colonize dead and weakened trees and speed succession of habitats altered by fire or bark beetles, while serving as prey for some early-seral habitat specialists, including several woodpecker species. To understand how these ecologically important beetles respond to different sources of tree mortality, we sampled woodborers in 16 sites affected by wildfire or bark beetle outbreak in the previous one to eight years. Study sites were located in the Sierra Nevada, Modoc Plateau, Warner Mountains, and southern Cascades of California, USA. We used generalized linear mixed models to evaluate hypotheses concerning the response of woodboring beetles to disturbance type, severity, and timing; forest stand composition and structure; and tree characteristics.</p
Family medicine graduates' perceptions of intimidation, harassment, and discrimination during residency training
<p>Abstract</p> <p>Background</p> <p>Despite there being considerable literature documenting learner distress and perceptions of mistreatment in medical education settings, these concerns have not been explored in-depth in Canadian family medicine residency programs. The purpose of the study was to examine intimidation, harassment and/or discrimination (IHD) as reported by Alberta family medicine graduates during their two-year residency program.</p> <p>Methods</p> <p>A retrospective questionnaire survey was conducted of all (n = 377) family medicine graduates from the University of Alberta and University of Calgary who completed residency training during 2001-2005. The frequency, type, source, and perceived basis of IHD were examined by gender, age, and Canadian vs international medical graduate. Descriptive data analysis (frequency, crosstabs), Chi-square, Fisher's Exact test, analysis of variance, and logistic regression were used as appropriate.</p> <p>Results</p> <p>Of 377 graduates, 242 (64.2%) responded to the survey, with 44.7% reporting they had experienced IHD while a resident. The most frequent type of IHD experienced was in the form of inappropriate verbal comments (94.3%), followed by work as punishment (27.6%). The main sources of IHD were specialist physicians (77.1%), hospital nurses (54.3%), specialty residents (45.7%), and patients (35.2%). The primary basis for IHD was perceived to be gender (26.7%), followed by ethnicity (16.2%), and culture (9.5%). A significantly greater proportion of males (38.6%) than females (20.0%) experienced IHD in the form of work as punishment. While a similar proportion of Canadian (46.1%) and international medical graduates (IMGs) (41.0%) experienced IHD, a significantly greater proportion of IMGs perceived ethnicity, culture, or language to be the basis of IHD.</p> <p>Conclusions</p> <p>Perceptions of IHD are prevalent among family medicine graduates. Residency programs should explicitly recognize and robustly address all IHD concerns.</p
The Opportunity Cost of the Conservation Reserve Program: A Kansas Land Example
The effects of the Conservation Reserve Program (CRP) on farmland values is investigated using a set of parcel-level data for land sales in Kansas over the period 1998 to 2014. The sales data are used to estimate a hedonic model of land values that allows for the opportunity cost of CRP enrollment to vary across space and time. Factors impacting the opportunity costs include the relative productivity of land, returns to farming, and the time remaining under the CRP contracts. We find that the discount associated with having land under CRP contract averages 7%
Polarization squeezing and continuous-variable polarization entanglement
The Stokes-parameter operators and the associated Poincare sphere, which
describe the quantum-optical polarization properties of light, are defined and
their basic properties are reviewed. The general features of the Stokes
operators are illustrated by evaluation of their means and variances for a
range of simple polarization states. Some of the examples show polarization
squeezing, in which the variances of one or more Stokes parameters are smaller
than the coherent-state value. The main object of the paper is the application
of these concepts to bright squeezed light. It is shown that a light beam
formed by interference of two orthogonally-polarized quadrature-squeezed beams
exhibits squeezing in some of the Stokes parameters. Passage of such a primary
polarization-squeezed beam through suitable optical components generates a pair
of polarization-entangled light beams with the nature of a two-mode squeezed
state. The use of pairs of primary polarization-squeezed light beams leads to
substantially increased entanglement and to the generation of EPR-entangled
light beams. The important advantage of these nonclassical polarization states
for quantum communication is the possibility of experimentally determining all
of the relevant conjugate variables of both squeezed and entangled fields using
only linear optical elements followed by direct detection.Comment: 27 pages, including 10 figure
The Mount Perkins block, northwestern Arizona: An exposed cross section of an evolving, preextensional to synextensional magmatic system
This is the published version. Reuse is subject to Society of Exploration Geophysicists terms of use and conditions.The steeply tilted Mount Perkins block, northwestern Arizona, exposes a cross section of a magmatic system that evolved through the onset of regional extension. New 40Ar/39Ar ages of variably tilted (0â90°) volcanic strata bracket extension between 15.7 and 11.3 Ma. Preextensional intrusive activity included emplacement of a composite Miocene laccolith and stock, trachydacite dome complex, and east striking rhyolite dikes. Related volcanic activity produced an âź18â16 Ma stratovolcano, cored by trachydacite domes and flanked by trachydacite-trachyandesite flows, and âź16 Ma rhyolite flows. Similar compositions indicate a genetic link between the stratovolcano and granodioritic phase of the laccolith. Magmatic activity synchronous with early regional extension (15.7â14.5 Ma) generated a thick, felsic volcanic sequence, a swarm of northerly striking subvertical rhyolite dikes, and rhyolite domes. Field relations and compositions indicate that the dike swarm and felsic volcanic sequence are cogenetic. Modes of magma emplacement changed during the onset of extension from subhorizontal sheets, east striking dikes, and stocks to northerly striking, subvertical dike swarms, as the regional stress field shifted from nearly isotropic to decidedly anisotropic with an east-west trending, horizontal least principal stress. Preextensional trachydacitic and preextensional to synextensional rhyolitic magmas were part of an evolving system, which involved the ponding of mantle-derived basaltic magmas and ensuing crustal melting and assimilation at progressively shallower levels. Major extension halted this system by generating abundant pathways to the surface (fractures), which flushed out preexisting crustal melts and hybrid magmas. Remaining silicic melts were quenched by rapid, upper crustal cooling induced by tectonic denudation. These processes facilitated eruption of mafic magmas. Accordingly, silicic magmatism at Mount Perkins ended abruptly during peak extension âź14.5 Ma and gave way to mafic magmatism, which continued until extension ceased
âAt âAmen Mealsâ Itâs Me and Godâ Religion and Gender: A New Jewish Womenâs Ritual
New ritual practices performed by Jewish women can serve as test cases for an examination of the phenomenon of the creation of religious rituals by women. These food-related rituals, which have been termed ââamen mealsââ were developed in Israel beginning in the year 2000 and subsequently spread to Jewish women in Europe and the United States. This study employs a qualitative-ethnographic methodology grounded in participant-observation and in-depth interviews to describe these nonobligatory, extra-halakhic rituals. What makes these rituals stand out is the womenâs sense that through these rituals they experience a direct con- nection to God and, thus, can change reality, i.e., bring about jobs, marriages, children, health, and salvation for friends and loved ones. The ââamenââ rituals also create an open, inclusive womanâs space imbued with strong spiritualâemotional energies that counter the womenâs religious marginality. Finally, the purposes and functions of these rituals, including identity building and displays of cultural capital, are considered within a theoretical framework that views ââdoing genderââ and ââdoing religionââ as an integrated experience
- âŚ