1,159 research outputs found
Spatio-Temporal Interpolation Is Accomplished by Binocular Form and Motion Mechanisms
Spatio-temporal interpolation describes the ability of the visual system to perceive shapes as whole figures (Gestalts), even if they are moving behind narrow apertures, so that only thin slices of them meet the eye at any given point in time. The interpolation process requires registration of the form slices, as well as perception of the shape's global motion, in order to reassemble the slices in the correct order. The commonly proposed mechanism is a spatio-temporal motion detector with a receptive field, for which spatial distance and temporal delays are interchangeable, and which has generally been regarded as monocular. Here we investigate separately the nature of the motion and the form detection involved in spatio-temporal interpolation, using dichoptic masking and interocular presentation tasks. The results clearly demonstrate that the associated mechanisms for both motion and form are binocular rather than monocular. Hence, we question the traditional view according to which spatio-temporal interpolation is achieved by monocular first-order motion-energy detectors in favour of models featuring binocular motion and form detection
Angiomatoid giant cellular blue nevus of vaginal wall associated with pregnancy
<p>Abstract</p> <p>Background</p> <p>Blue nevi that arise from the Müllerian tract are rare melanocytic lesions. Several histopathologic variants of cellular blue nevi have been described. The angiomatoid variant is characterized by a vascular component, and is considered to be a rare variant. Few studies have explored the influence of pregnancy on melanocytic lesions.</p> <p>Case</p> <p>A 29-year-old woman was presented with a pigmented vaginal lesion that increased gradually during pregnancy. A full term gynecologic examination showed a tumor mass protruding into the vaginal canal. The mass was resected during cesarean-section under the clinical impression of vaginal hemangioma.</p> <p>Result</p> <p>Gross examination revealed a cystic mass measuring 6.0 × 4.3 × 3.5 cm, which was filled with dark friable material. Histologically, the mass showed a subepithelial cellular proliferation of heavily pigmented dendritic melanocytes with prominent vascular stroma. Cytologic pleomorphism, junctional activity, atypical mitosis, and necrosis were not found. The proliferation was immunoreactive for HMB-45, S-100 and melan-A, and non-immunoreactive for CD34, smooth muscle actin, and AE1/AE3. The MIB-1 proliferative index was less than 1%. The patient had a postoperative course without complication.</p> <p>Conclusions</p> <p>Angiomatoid giant cellular blue nevus arising from the vagina during pregnancy is extremely rare. The low proliferative index and absence of cytologic pleomorphism, or necrosis, supports a benign biological behavior. Clinical follow-up showed no evidence of recurrence at one year after the resection of the mass.</p
The contribution of microlensing surveys to the distance scale
In the early nineties several teams started large scale systematic surveys of
the Magellanic Clouds and the Galactic Bulge to search for microlensing
effects. As a by product, these groups have created enormous time-series
databases of photometric measurements of stars with a temporal sampling
duration and accuracy which are unprecedented. They provide the opportunity to
test the accuracy of primary distance indicators, such as Cepheids, RRLyrae
stars, the detached eclipsing binaries, or the luminosity of the red clump. We
will review the contribution of the microlensing surveys to the understanding
of the physics of the primary distance indicators, recent differential studies
and direct distance determinations to the Magellanic Clouds and the Galactic
Bulge.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles',
A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in press. 21
pages; uses Kluwer's crckapb.sty LaTeX style file, enclose
African Rice (Oryza glaberrima Steud.): Lost Crop of the Enslaved Africans Discovered in Suriname1
African Rice (Oryza glaberrimaSteud.): Lost Crop of the Enslaved Africans Discovered in Suriname. African rice (Oryza glaberrima Steud.) was introduced to the Americas during the slave trade years and grown by enslaved Africans for decades before mechanical milling devices facilitated the shift towards Asian rice (O. sativa L.). Literature suggests that African rice is still grown in Guyana and French Guiana, but the most recent herbarium voucher dates from 1938. In this paper, evidence is presented that O. glaberrima is still grown by Saramaccan Maroons both for food and ritual uses. Saramaccan informants claim their forefathers collected their first “black rice” from a mysterious wild rice swamp and cultivated these seeds afterwards. Unmilled spikelets (grains with their husk still attached) are sold in small quantities for ancestor offerings, and even exported to the Netherlands to be used by Maroon immigrants. Little is known of the evolution of O. glaberrima, before and after domestication. Therefore, more research is needed on the different varieties of rice and other “lost crops” grown by these descendants of enslaved Africans who escaped from plantations in the 17th and 18th centuries and maintained much of their African cultural heritage in the deep rainforest
Developing a decision aid to guide public sector health policy decisions: A study protocol
<p>Abstract</p> <p>Background</p> <p>Decision aids have been developed in a number of health disciplines to support evidence-informed decision making, including patient decision aids and clinical practice guidelines. However, policy contexts differ from clinical contexts in terms of complexity and uncertainty, requiring different approaches for identifying, interpreting, and applying many different types of evidence to support decisions. With few studies in the literature offering decision guidance specifically to health policymakers, the present study aims to facilitate the structured and systematic incorporation of research evidence and, where there is currently very little guidance, values and other non-research-based evidence, into the policy making process. The resulting decision aid is intended to help public sector health policy decision makers who are tasked with making evidence-informed decisions on behalf of populations. The intent is not to develop a decision aid that will yield uniform recommendations across jurisdictions, but rather to facilitate more transparent policy decisions that reflect a balanced consideration of all relevant factors.</p> <p>Methods/design</p> <p>The study comprises three phases: a modified meta-narrative review, the use of focus groups, and the application of a Delphi method. The modified meta-narrative review will inform the initial development of the decision aid by identifying as many policy decision factors as possible and other features of methodological guidance deemed to be desirable in the literatures of all relevant disciplines. The first of two focus groups will then seek to marry these findings with focus group members' own experience and expertise in public sector population-based health policy making and screening decisions. The second focus group will examine issues surrounding the application of the decision aid and act as a sounding board for initial feedback and refinement of the draft decision aid. Finally, the Delphi method will be used to further inform and refine the decision aid with a larger audience of potential end-users.</p> <p>Discussion</p> <p>The product of this research will be a working version of a decision aid to support policy makers in population-based health policy decisions. The decision aid will address the need for more structured and systematic ways of incorporating various evidentiary sources where applicable.</p
Psychiatric disorder in early adulthood and risk of premature mortality in the 1946 British Birth Cohort
<p>Abstract</p> <p>Background</p> <p>Few studies of the association between psychiatric disorder and premature death have adjusted for key confounders and used structured psychiatric interviews. We aimed to investigate if psychiatric disorder was associated with a higher risk of mortality and whether any excess mortality was due to suicide, or explained by other health or socioeconomic risk factors.</p> <p>Methods</p> <p>We used data from the MRC National Survey of Health and Development, a nationally representative UK birth cohort. 3283 men and women completed the Present State Examination at age 36. The main outcome measure was all-cause mortality before age 60.</p> <p>Results</p> <p>Those with psychiatric disorder at age 36 had a higher risk of death even after adjusting for potential confounders (Hazard ratio = 1.84, 95% C.I. 1.22-2.78). Censoring violent deaths and suicides led to similar results.</p> <p>Conclusions</p> <p>Psychiatric disorder was associated with excess premature mortality not explained by suicide or other health or socioeconomic risk factors.</p
Links between plant and fungal communities across a deforestation chronosequence in the Amazon rainforest
Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests. © 2014 International Society for Microbial Ecology All rights reserved
Perceptions and Attitudes of Egyptian Health Professionals and Policy-Makers towards Pharmaceutical Sales Representatives and Other Promotional Activities
Pharmaceutical promotion activities in low and middle-income countries are often neither regulated nor monitored. While Egypt has the highest population and per capita use of medicines in the Arab world, we know very little about pharmaceutical companies promotional activities in the country.To explore and analyze the perceptions of physicians towards promotional and marketing activities of pharmaceutical companies among physicians and pharmacists in Egypt.Perspectives of different healthcare system stakeholders were explored through semi-structured, in-depth interviews conducted in 2014 in Cairo, Egypt. Interviewees were chosen via purposive sampling and snowball technique. Each interview was recorded and transcribed. Then qualitative, thematic analysis was conducted with the help of NVIVO software.The majority of physicians and pharmacists acknowledged exposure to pharmaceutical promotion. It was commonly believed that interaction with the pharmaceutical industry is necessary and both associated risks and benefits were acknowledged. The interviewed physicians considered themselves competent enough to minimize risks and maximize benefits to their prescribing habits. Views diverged on the extent and magnitude of the risks and benefits of pharmaceutical promotion, especially in regard to the influence on patients' health.Pharmaceutical promotion in Egypt is intensely directed at prescribers and dispensers. Physicians, pharmacists and policymakers expressed little skepticism to the influence of promotion towards their individual prescribing. Raising awareness of the pitfalls of pharmaceutical promotion is necessary, especially among the less experienced physicians
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