331 research outputs found

    A teaser made simple: a didactic measurement of the spectral answer of a human-eye-calibrated lux meter

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    A simple didactic experiment has been designed and realized, in order to illustrate to undergraduate students in scientific faculties some basic concepts lying behind the fundamentals of geometrical optics. The spectral response of a human-eye-calibrated lux meter was measured using a very trivial experimental arrangement. The white light of a halogen lamp was decomposed into its spectral components through a diffraction grating, so that collecting the radiation at different dispersion angles allowed one to measure the intensity as a function of wavelength. The experiment can be used to effectively illustrate the concepts of spectral distribution, the radiometry versus photometry conversion and photopic response, and the famous historical experience by Herschel on the 'temperature of colours'

    Finding home: the final step of the pigeons' homing process studied with a GPS data logger

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    Experiments have shown that homing pigeons are able to develop navigational abilities even if reared and kept confined in an aviary, provided that they are exposed to natural winds. These and other experiments performed on inexperienced birds have shown that previous homing experiences are not necessary to determine the direction of displacement. While the cues used in the map process for orienting at the release site have been extensively investigated, the final step of the homing process has received little attention by researchers. Although there is general agreement on the relevance of visual cues in navigation within the home area, there is a lack of clear evidence. In order to investigate the final step of the homing process, we released pigeons raised under confined conditions and others that had been allowed to fly freely around the loft and compared their flight paths recorded with a Global-Positioning-System logger. Our data show that a limited view of the home area impairs the pigeons' ability to relocate the loft at their first homing flight, suggesting that the final step of the homing process is mediated via recognition of familiar visual landmarks in the home area

    Correlations Between Gender, Age, and Occupational Factors on the Work Ability Index Among Healthcare Professionals

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    Background: The Work Ability Index (WAI) measures how well employees' abilities match their job demands. This study assessed the WAI among health workers and explored how age, gender, and job roles affected it. The research was conducted in a central Italian hospital, with a focus on health workers undergoing health surveillance between September 2020 and April 2021. Methods: Data were collected using validated questionnaires that assessed the WAI and risk factors for metabolic syndrome among participants. Demographic information, including age, gender, and occupation, was also obtained. The study involved 1847 health workers, with an average age of 43 years, predominantly women (67.6%). Occupational categories included administrative staff, nurses/healthcare workers (HCWs)/midwives, physicians, and healthcare technicians. Statistical analyses, such as t-tests, ANOVA, and chi-squared tests, were performed to explore the relationships between WAI scores and demographic/occupational variables. Results: The study suggested a relationship between WAI scores and gender, age, and occupation. Men workers exhibited higher mean WAI scores than women workers, while older workers (>55 years) had lower WAI scores compared with their younger counterparts. WAI scores varied by job role, with physicians scoring the highest. Conclusions: The findings suggested that demographic and occupational factors were associated with variations in work ability among health workers. These findings can help improve workforce management, occupational health, and research on aging workers. However, it is important to acknowledge the limitations of this study. Given its cross-sectional design, causal inferences cannot be established, and further longitudinal research is needed to confirm these findings and explore potential causal relationships

    Long-term clinical outcomes in critical limb ischemia--A retrospective study of 181 patients

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    Critical limb ischemia (CLI) is the most severe manifestation of the peripheral arterial disease. To date, several prognostic factors have been identified but the data of long-term follow-up in real life setting are scarce. The aim of our study is to describe a large group of CLI patients and identify possible prognostic factors, in a long-term follow-up

    Long-term survival of patients with critical limb ischemia treated with iloprost: response rate and predictive criteria. A retrospective analysis of 102 patients

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    Critical limb ischemia (CLI) patients have poor long-term prognosis. We showed that iloprost improves outcomes (major amputation and survival) up a 5-year follow-up, but it is not known if in this length of time the survival curves, of clinical responders and non-responders, differ

    Fluorescein angiography findings in eyes with lamellar macular hole and epiretinal membrane foveoschisis

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    PURPOSE. The purpose of this paper was to study fluorescein angiography (FA) findings in eyes with lamellar macular hole (LMH), and epiretinal membrane (ERM) foveoschisis. METHODS. In this prospective, observational case series, 46 eyes of patients affected by either LMH or ERM foveoschisis were examined using optical coherence tomography (OCT) and FA. All patients underwent a comprehensive ophthalmological examination and a general workup to exclude uveitis. Main outcome measures were: presence of FA abnormalities, measurements of the areas of vascular leakage, and intensity of pixels in the vitreous. RESULTS. Twenty-four (52.2%) eyes with LMH and 22 (47.8%) with ERM foveoschisis were studied. Overall, FA abnormalities were found in 20 (83.3%) eyes with LMH and 18 (81.8%) with ERM foveoschisis. The median areas of posterior pole and peripheral leakage were 7.52 vs. 1.07 mm2 (P = 0.03) and 21.8 vs. 3.74 mm2 (P = 0.02) in the LMH and ERM foveoschisis group, respectively. Disk hyperfluorescence was found in 8 and 4 eyes and perivascular leak in 10 and 4 eyes with LMH and ERM foveoschisis, respectively. OCT-derived measurements of vitreous intensity did not differ between the two groups, and the investigational workup for uveitis was negative in all patients. CONCLUSIONS. Discrete areas of central and peripheral leakage are commonly found in eyes with LMH and ERM foveoschisis, whereas perivascular leak and hyperfluorescence of the disc are less frequently observed. These findings suggest that breakdown of the retinal blood barrier, involving the posterior pole and the periphery, is frequently associated with these two vitreoretinal disorders

    Primary vitrectomy for degenerative and tractional lamellar macular holes: A systematic review and meta-analysis

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    Purpose To assess the efficacy of vitrectomy in degenerative and tractional lamellar macular holes (LMHs) by meta-analysis of published studies. Methods PubMed, Medline and Embase databases were searched up to May 2020. Included cohorts were divided into three groups: degenerative LMH group, lamellar hole associated epiretinal proliferation (LHEP) group and tractional LMH group. LHEP is likely to be associated with degenerative LMHs, but less commonly could be associated with mixed LMHs. To reduce risk of possible misclassification bias, eyes with LHEP which could not have been precisely classified by the authors, were included into the LHEP group. The primary outcome was to investigate the visual change following primary vitrectomy in the degenerative LMH and LHEP group versus the tractional LMH group. A sensitivity analysis excluding the LHEP group was also performed on the primary outcome. Mean difference (MD) in best corrected visual acuity between baseline and post-treatment was calculated, along with 95% confidence interval (CI). Rate of incidence of post-operative full-thickness macular hole (FTMH) was assessed as secondary outcome. Results Thirteen studies were included. Pooled analyses including all groups showed a significant visual improvement following vitrectomy (pre-post MD = -0.17;95%CI = -0.22,-0.12; p<0.001), with no difference in visual improvement between the degenerative LMH and LHEP group and the tractional LMH group. The sensitivity analysis excluding LHEP group confirmed no difference in visual change between the degenerative LMH group (pre-post MD = -0.18;95%CI = -0.24,-0.12;p<0.001) and the tractional LMH group (MD = -0.16;95%CI = -0.26,-0.07;p<0.001). The incidence rate of post-operative FTMH was higher in the degenerative LMH and LHEP group than in the tractional LMH group (p = 0.002). Conclusion Primary vitrectomy for LMH ensured a favorable visual outcome, with no difference in visual gain between degenerative and tractional LMHs. However, a higher incidence of post-operative FTMHs was found in eyes with the degenerative LMH subtype
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