213 research outputs found
Cortical Cataract and Refractive Error
Purpose: To evaluate the relationship between the presence
of cortical cataract and accommodation effort, using refractive
error as a proxy. Methods: Patients between 50 and 90
years, scheduled for cataract surgery, were selected with the
help of a photographic database. Nuclear and cortical cataract
were graded and patients grouped having no cataract,
pure cortical, mixed or pure nuclear cataract. Refraction data
at the time of the photograph was converted to estimated
spherical equivalent refractive error each patient would
have had at the age of 45 years. Results: From the initial 239
eyes from 239 patients, cases with myopia below â6.5 dpt
and hyperopia above 6.5 dpt were excluded, resulting in 199
cases for final analysis. Eyes with no cataract showed the
lowest median refractive error (â3.65 dpt), followed by the
pure nuclear group (â2.69 dpt). The median refractive error
for pure cortical (â0.23 dpt) and mixed cataracts (â0.87 dpt)
were close to emmetropia. Cortical cataracts were found in
37% of myopes, 82% of emmetropes, and 85% of hyperopes.
Conclusion: Emmetropes and hyperopes tend to develop
more cortical cataract than myopes. These cortical cataracts
might be caused by shear stress inside the crystalline lens
due to accommodation efforts at the time of onset of presbyopia
The effect of thermal treatment on structure and surface composition of PtCo electro-catalysts for application in PEMFCs operating under automotive conditions
The effect of thermal treatment on structure and surface composition of PtCo electro-catalysts for application in PEMFCs operating under automotive conditions
Ontem, como aqui escrevi, JosĂŠ Eduardo Moniz, Director-Geral da TVI, fez uma conferĂŞncia intitulada A TelevisĂŁo num Mundo Audiovisual em Mudança na UCP. No vĂdeo, Moniz fala de seis assuntos: 1) televisĂŁo generalista e novas plataformas, 2) perfil de oferta para o telespectador, 3) surgimento do quinto canal, 4) trĂŞs canais de notĂcias, 5) programação de qualidade, e 6) blocos informativos
Protecting Important Sites for Biodiversity Contributes to Meeting Global Conservation Targets
Abstract Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and trends in species' extinction risk at globally significant sites for conserving birds (10,993 Important Bird Areas, IBAs) and highly threatened vertebrates and conifers (588 Alliance for Zero Extinction sites, AZEs) (referred to collectively hereafter as 'important sites'). Species occurring in important sites with greater PA coverage experienced smaller increases in extinction risk over recent decades: the increase was half as large for bird species with.50% of the IBAs at which they occur completely covered by PAs, and a third lower for birds, mammals and amphibians restricted to protected AZEs (compared with unprotected or partially protected sites). Globally, half of the important sites for biodiversity conservation remain unprotected (49% of IBAs, 51% of AZEs). While PA coverage of important sites has increased over time, the proportion of PA area covering important sites, as opposed to less important land, has declined (by 0.45-1.14% annually since 1950 for IBAs and 0.79-1.49% annually for AZEs). Thus, while appropriately located PAs may slow the rate at which species are driven towards extinction, recent PA network expansion has under-represented important sites. We conclude that better targeted expansion of PA networks would help to improve biodiversity trends
Protecting Important Sites for Biodiversity Contributes to Meeting Global Conservation Targets
Abstract Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and trends in species' extinction risk at globally significant sites for conserving birds (10,993 Important Bird Areas, IBAs) and highly threatened vertebrates and conifers (588 Alliance for Zero Extinction sites, AZEs) (referred to collectively hereafter as 'important sites'). Species occurring in important sites with greater PA coverage experienced smaller increases in extinction risk over recent decades: the increase was half as large for bird species with.50% of the IBAs at which they occur completely covered by PAs, and a third lower for birds, mammals and amphibians restricted to protected AZEs (compared with unprotected or partially protected sites). Globally, half of the important sites for biodiversity conservation remain unprotected (49% of IBAs, 51% of AZEs). While PA coverage of important sites has increased over time, the proportion of PA area covering important sites, as opposed to less important land, has declined (by 0.45-1.14% annually since 1950 for IBAs and 0.79-1.49% annually for AZEs). Thus, while appropriately located PAs may slow the rate at which species are driven towards extinction, recent PA network expansion has under-represented important sites. We conclude that better targeted expansion of PA networks would help to improve biodiversity trends
A Comparative Environmental Assessment for the Synthesis of 1,3-Oxazin-2-one by Metrics: Greenness Evaluation and Blind Spots
Alternative syntheses for the production of 3-benzyl-1,3-oxazinan-2-one are compared and evaluated employing
green metrics. An environmental assessment has been performed using the algorithm recently developed by Andraos that takes
into account the mass flows and the software EATOS that considers mass flows, environmental impacts of the substances
involved, and waste produced. Strengths and critical spots of the environmental tools employed are also discussed. Data collected
showed that the synthesis employing diethyl carbonate is the most promising one, having the lowest environmental impact
Chemical Behavior and Reaction Kinetics of Sulfur and Nitrogen Half-Mustard and Iprit Carbonate Analogues
Sulfur and nitrogen mustards are very toxic, yet versatile organic molecules with numerous applications. Herein, we report on a synthesis of a new class of green compounds, i.e., half-mustard and iprit carbonates, that result in new, unexplored, and safe molecules. Their chemical behavior with several nucleophiles and their reaction kinetics have been investigated
One-step hydrothermal synthesis of graphene decorated V2O5 nanobelts for enhanced electrochemical energy storage
Graphene-decorated V2O5 nanobelts (GVNBs) were synthesized via a low-temperature hydrothermal method in a single step. V2O5 nanobelts (VNBs) were formed in the presence of graphene oxide, a mild oxidant, which also enhanced the conductivity of GVNBs. From the electron energy loss spectroscopy analysis, the reduced graphene oxide (rGO) are inserted into the layered crystal structure of V2O5 nanobelts, which further confirmed the enhanced conductivity of the nanobelts. The electrochemical energy-storage capacity of GVNBs was investigated for supercapacitor applications. The specific capacitance of GVNBs was evaluated using cyclic voltammetry (CV) and charge/discharge (CD) studies. The GVNBs having V2O5-rich composite, namely, V(3)G(1) (VO/GO = 3:1), showed superior specific capacitance in comparison to the other composites (V(1)G(1) and V(1)G(3)) and the pure materials. Moreover, the V(3)G(1) composite showed excellent cyclic stability and the capacitance retention of about 82% was observed even after 5000 cycles.open
Protecting Important Sites for Biodiversity Contributes to Meeting Global Conservation Targets
Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and trends in species' extinction risk at globally significant sites for conserving birds (10,993 Important Bird Areas, IBAs) and highly threatened vertebrates and conifers (588 Alliance for Zero Extinction sites, AZEs) (referred to collectively hereafter as âimportant sitesâ). Species occurring in important sites with greater PA coverage experienced smaller increases in extinction risk over recent decades: the increase was half as large for bird species with>50% of the IBAs at which they occur completely covered by PAs, and a third lower for birds, mammals and amphibians restricted to protected AZEs (compared with unprotected or partially protected sites). Globally, half of the important sites for biodiversity conservation remain unprotected (49% of IBAs, 51% of AZEs). While PA coverage of important sites has increased over time, the proportion of PA area covering important sites, as opposed to less important land, has declined (by 0.45â1.14% annually since 1950 for IBAs and 0.79â1.49% annually for AZEs). Thus, while appropriately located PAs may slow the rate at which species are driven towards extinction, recent PA network expansion has under-represented important sites. We conclude that better targeted expansion of PA networks would help to improve biodiversity trends
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