A Rapid Assessment of Avoidable Blindness in Southern Zambia

INTRODUCTION: A rapid assessment of avoidable blindness (RAAB) was conducted in Southern Zambia to establish the prevalence and causes of blindness in order to plan effective services and advocate for support for eye care to achieve the goals of VISION 2020: the right to sight. METHODS: Cluster randomisation was used to select villages in the survey area. These were further subdivided into segments. One segment was selected randomly and a survey team moved from house to house examining everyone over the age of 50 years. Each individual received a visual acuity assessment and simple ocular examination. Data was recorded on a standard proforma and entered into an established software programme for analysis. RESULTS: 2.29% of people over the age of 50 were found to be blind (VA <3/60 in the better eye with available correction). The major cause of blindness was cataract (47.2%) with posterior segment disease being the next main cause (18.8%). 113 eyes had received cataract surgery with 30.1% having a poor outcome (VA <6/60) following surgery. Cataract surgical coverage showed that men (72%) received more surgery than women (65%). DISCUSSION: The results from the RAAB survey in Zambia were very similar to the results from a similar survey in Malawi, where the main cause of blindness was cataract but posterior segment disease was also a significant contributor. Blindness in this part of Zambia is mainly avoidable and there is a need for comprehensive eye care services that can address both cataract and posterior segment disease in the population if the aim of VISION 2020 is to be achieved. Services should focus on quality and gender equity of cataract surgery

Just Noticeable Difference of dead pixels in monochrome computer-generated holograms

Computer-generated holography (CGH) is a method for replicating scenes that incorporates depth, making them potentially much more realistic than traditional displays. Because CGH uses diffractive optics to generate scenes, holograms are also significantly more robust against dead pixels: while a single dead pixel is often noticeable in traditional displays, in holography much higher numbers are needed before a viewer realises the issue. This work is a pilot study to determine the Just Noticeable Difference of the number of dead pixels of a hologram, i.e., the minimum amount that need to be added before a viewer notices the difference. From these JNDs a quality ruler will be generated, which later work will use to compare the impact of other distortions on the perceived quality of a hologram. Results thus far suggest an addition of 4% dead pixels is required to notice a difference, which is significantly greater than the tolerance observed for traditional displays, where the fault class threshold is less than 0.05%

A Mixed-Methods Evaluation of a Community-Based Glaucoma Check Service in Hackney, London, UK.

: To evaluate the uptake, feasibility and acceptability of a general practice-based optometrist-led glaucoma check service. The service targeted people of black Caribbean and black African descent aged 40-65 years, resident in Hackney, London, United Kingdom. : The study used a mixed-method design, including analysis of service data, prospective audit of secondary care referrals patient survey, cost-consequence analysis, and interviews with staff involved in developing and implementing the service. : A total of 3040 patients were invited to undergo the free check; 595 (19.6%) booked an appointment and 461 (15.2%) attended. Overall, 31 patients (6.8%) were referred to secondary care, of whom 22 attended and were assessed for glaucoma. Four were diagnosed with glaucoma and eight with suspected glaucoma, i.e. 2.6% of patients who underwent the check. The cost per patient identified with suspected or confirmed glaucoma was £9,013. Staff who were interviewed suggested that patients who attended might be those who routinely attended optometrist appointments, however only 62.4% of survey respondents reported having had an eye examination in the previous two years, and 11.4% of women and 16.0% of men reported never having had an eye examination. : This study represents one possible configuration for a glaucoma case-finding service, and it contributes to a wider debate about whether screening, targeted or otherwise, should be offered in the UK. Our findings suggest that general practice is an acceptable setting and that such a service may reach some people not previously engaged with primary eye care services.<br/

Parenting interventions for male young offenders: a review of the evidence on what works

Approximately one in four incarcerated male young offenders in the UK is an actual or expectant father. This paper reviews evidence on the effectiveness of parenting interventions for male young offenders. We conducted systematic searches across 20 databases and consulted experts. Twelve relevant evaluations were identified: 10 from the UK, of programmes for incarcerated young offenders, and two from the US, of programmes for young parolees. None used experimental methods or included a comparison group. They suggest that participants like the courses, find them useful, and the interventions may improve knowledge about, and attitudes to, parenting. Future interventions should incorporate elements of promising parenting interventions with young fathers in the community, for example, and/or with older incarcerated parents. Young offender fathers have specific developmental, rehabilitative, and contextual needs. Future evaluations should collect longer-term behavioural parent and child outcome data and should use comparison groups and, ideally, randomization

Coagulation activity of stored blood at +4°C

U ovom je radu ispitana koagulaciona aktivnost uskladištene krvi na +4°C. Primijenjeno je osam koagulacionih testova, a promjene koagulacione aktivnosti prikazane su grafički. Testiranje je izvršeno odmah nakon vađenja krvi, te drugi, sedmi i četrnaesti dan. Rezultati autora uspoređeni su s rezultatima iz literature.The coagulation activity of blood stored at 4°C was investigated. Eight different clotting tests were used. The changes in the coagulation activity are presented graphically. The testing was performed .immediately after the blood was taken from the vein and then after the first, seventh and forteenth day of storage. The authors compare their results with the data reported in literature. On each figure the time of storage in days is marked on the abscissa. The ordinate indicates the clotting time in sec. (Fig. 1), the prothrombin time in sec. (Fig. 2), the prothrombin consumption test in sec. (Fig. 3), the number of platelets x 10-3 (Fig. 4), the tromboplastin generation test, % activity (Fig. 5), the antihemophilic globulin % (Fig. 6), factor V activity % (Fig. 7), factor VII activity % (Fig. 8)

Assessing Fish and Motile Fauna around Offshore Windfarms Using Stereo Baited Video

There remains limited knowledge of how offshore windfarm developments influence fish assemblages, particularly at a local scale around the turbine structures. Considering the existing levels of anthropogenic pressures on coastal fish populations it is becoming increasingly important for developers and environmental regulators to gain a more comprehensive understanding of the factors influencing fish assemblages. Improving our ability to assess such fish populations in close proximity to structures will assist in increasing this knowledge. In the present study we provide the first trial use of Baited Remote Underwater Stereo-Video systems (stereo BRUVs) for the quantification of motile fauna in close proximity to offshore wind turbines. The study was conducted in the Irish Sea and finds the technique to be a viable means of assessing the motile fauna of such environments. The present study found a mixture of species including bottom dwellers, motile crustaceans and large predatory fish. The majority of taxa observed were found to be immature individuals with few adult individuals recorded. The most abundant species were the angular crab (Goneplax rhomboides) and the small-spotted catshark (Scyliorhinus canicula). Of note in this study was the generally low abundance and diversity of taxa recorded across all samples, we hypothesise that this reflects the generally poor state of the local fauna of the Irish Sea. The faunal assemblages sampled in close proximity to turbines were observed to alter with increasing distance from the structure, species more characteristic of hard bottom environments were in abundance at the turbines (e.g. Homarus gammarus, Cancer pagarus, Scyliorhinus spp.) and those further away more characteristic of soft bottoms (e.g. Norwegian Lobster). This study highlights the need for the environmental impacts of offshore renewables on motile fauna to be assessed using targeted and appropriate tools. Stereo BRUVs provide one of those tools, but like the majority of methods for sampling marine biota, they have limitations. We conclude our paper by providing a discussion of the benefits and limitations of using this BRUV technique for assessing fauna within areas close to offshore windfarms

A field and video-annotation guide for baited remote underwater stereo-video surveys of demersal fish assemblages

Researchers TL, BG, JW, NB and JM were supported by the Marine Biodiversity Hub through funding from the Australian Government's National Environmental Science Program. Data validation scripts and GlobalArchive.org were supported by the Australian Research Data Commons, the Gorgon-Barrow Island Gorgon Barrow Island Net Conservation Benefits Fund, administered by the Government of Western Australia and the BHP/UWA Biodiversity and Societal Benefits of Restricted Access Areas collaboration.1. Baited remote underwater stereo-video systems (stereo-BRUVs) are a popular tool to sample demersal fish assemblages and gather data on their relative abundance and body-size structure in a robust, cost-effective, and non-invasive manner. Given the rapid uptake of the method, subtle differences have emerged in the way stereo-BRUVs are deployed and how the resulting imagery are annotated. These disparities limit the interoperability of datasets obtained across studies, preventing broad-scale insights into the dynamics of ecological systems. 2. We provide the first globally accepted guide for using stereo-BRUVs to survey demersal fish assemblages and associated benthic habitats. 3. Information on stereo-BRUV design, camera settings, field operations, and image annotation are outlined. Additionally, we provide links to protocols for data validation, archiving, and sharing. 4. Globally, the use of stereo-BRUVs is spreading rapidly. We provide a standardised protocol that will reduce methodological variation among researchers and encourage the use of Findable, Accessible, Interoperable, and Reproducible (FAIR) workflows to increase the ability to synthesise global datasets and answer a broad suite of ecological questions.Publisher PDFPeer reviewe

Depth refuge and the impacts of SCUBA spearfishing on coral reef fishes

In recent decades, spearfishing with SCUBA has emerged as an efficient method for targeting reef fish in deeper waters. However, deeper waters are increasingly recognised as a potential source of refuge that may help sustain fishery resources. We used a combination of historical catch data over a 20-year time period and fishery-independent surveys to investigate the effects of SCUBA spearfishing on coral reef fish populations in the southern Mariana Islands. Two jurisdictions were studied; Guam, where SCUBA spearfishing is practiced, and the nearby Commonwealth of Northern Mariana Islands (CNMI), where SCUBA spearfishing has been banned since 2003. Fishery-independent data were collected using baited remote underwater stereo-video systems (stereo-BRUVs) stratified by depth, marine protected area status and jurisdiction. Herbivores (primary consumers) dominated spearfishing catches, with parrotfish (scarines) and surgeonfish/unicornfish (acanthurids) the main groups harvested. However, the large, endangered humphead wrasse (Cheilinus undulatus) was the main species by weight landed by SCUBA spearfishers. SCUBA spearfishing was associated with declining size of scarines over time and catches shifting from a dominance of large parrotfishes to a mixed assemblage with increasing proportions of acanthurids. Comparisons between Guam and the nearby CNMI revealed differences in the assemblage of fished species and also greater size of scarines and acanthurids in deep water where SCUBA fishing is banned. These results suggest that SCUBA spearfishing impacts reef fish populations and that the restriction of this fishing method will ensure refuge for fish populations in deeper waters. We recommend a ban on SCUBA spearfishing to preserve or aid the recovery of large, functionally important coral reef species and to improve the sustainability of coral reef fisheries

An Inverse Method to Obtain Porosity, Fibre Diameterand Density of Fibrous Sound Absorbing Materials

Characterization of sound absorbing materials is essential to predict its acoustic behaviour. The most commonly used models to do so consider the flow resistivity, porosity, and average fibre diameter as parameters to determine the acoustic impedance and sound absorbing coefficient. Besides direct experimental techniques, numerical approaches appear to be an alternative to estimate the material's parameters. In this work an inverse numerical method to obtain some parameters of a fibrous material is presented. Using measurements of the normal incidence sound absorption coefficient and then using the model proposed by Voronina, subsequent application of basic minimization techniques allows one to obtain the porosity, average fibre diameter and density of a sound absorbing material. The numerical results agree fairly well with the experimental data.This work has been supported by the Ministerio de Educacion y Ciencia-D.G. Investigacion (BIA2007-68098-C02-01 and BIA2007-68098-C02-02) and also from the Spanish Ministry of Foreign Affairs and Cooperation through the Inter-University and Scientific Research Cooperation Program (A/023748/09).Alba Fernández, J.; Rey Tormos, RMD.; Ramis Soriano, J.; Arenas, JP. (2011). An Inverse Method to Obtain Porosity, Fibre Diameterand Density of Fibrous Sound Absorbing Materials. Archives of Acoustics. 36(3):561-574. https://doi.org/10.2478/v10168-011-0040-xS561574363Allard, J., & Champoux, Y. (1992). New empirical equations for sound propagation in rigid frame fibrous materials. The Journal of the Acoustical Society of America, 91(6), 3346-3353. doi:10.1121/1.402824Attenborough, K. (1983). Acoustical characteristics of rigid fibrous absorbents and granular materials. The Journal of the Acoustical Society of America, 73(3), 785-799. doi:10.1121/1.389045Bies, D. A., & Hansen, C. H. (1980). Flow resistance information for acoustical design. Applied Acoustics, 13(5), 357-391. doi:10.1016/0003-682x(80)90002-xChampoux, Y., Stinson, M. R., & Daigle, G. A. (1991). Air‐based system for the measurement of porosity. The Journal of the Acoustical Society of America, 89(2), 910-916. doi:10.1121/1.1894653Crocker, M. J., & Arenas, J. P. (s. f.). Use of Sound-Absorbing Materials. Handbook of Noise and Vibration Control, 696-713. doi:10.1002/9780470209707.ch57Delany, M. E., & Bazley, E. N. (1970). Acoustical properties of fibrous absorbent materials. Applied Acoustics, 3(2), 105-116. doi:10.1016/0003-682x(70)90031-9Dunn, I. P., & Davern, W. A. (1986). Calculation of acoustic impedance of multi-layer absorbers. Applied Acoustics, 19(5), 321-334. doi:10.1016/0003-682x(86)90044-7Fellah, Z. E. A., Berger, S., Lauriks, W., Depollier, C., Aristégui, C., & Chapelon, J.-Y. (2003). Measuring the porosity and the tortuosity of porous materials via reflected waves at oblique incidence. The Journal of the Acoustical Society of America, 113(5), 2424-2433. doi:10.1121/1.1567275Fellah, Z. E. A., Berger, S., Lauriks, W., Depollier, C., & Fellah, M. (2003). Measuring the porosity of porous materials having a rigid frame via reflected waves: A time domain analysis with fractional derivatives. Journal of Applied Physics, 93(1), 296-303. doi:10.1063/1.1524025Fellah, Z. E. A., Berger, S., Lauriks, W., Depollier, C., Trompette, P., & Chapelon, J. Y. (2003). Ultrasonic measurement of the porosity and tortuosity of air-saturated random packings of beads. Journal of Applied Physics, 93(11), 9352-9359. doi:10.1063/1.1572191Fellah, Z. E. A., Mitri, F. G., Fellah, M., Ogam, E., & Depollier, C. (2007). Ultrasonic characterization of porous absorbing materials: Inverse problem. Journal of Sound and Vibration, 302(4-5), 746-759. doi:10.1016/j.jsv.2006.12.007Garai, M., & Pompoli, F. (2005). A simple empirical model of polyester fibre materials for acoustical applications. 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Applied Acoustics, 59(1), 77-87. doi:10.1016/s0003-682x(99)00015-8Umnova, O., Attenborough, K., Shin, H.-C., & Cummings, A. (2005). Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials. Applied Acoustics, 66(6), 607-624. doi:10.1016/j.apacoust.2004.02.005Voronina, N. (1994). Acoustic properties of fibrous materials. Applied Acoustics, 42(2), 165-174. doi:10.1016/0003-682x(94)90005-1Voronina, N. (1996). Improved empirical model of sound propagation through a fibrous material. Applied Acoustics, 48(2), 121-132. doi:10.1016/0003-682x(95)00055-eVoronina, N. (1998). An empirical model for elastic porous materials. Applied Acoustics, 55(1), 67-83. doi:10.1016/s0003-682x(97)00098-4Voronina, N. (1999). An empirical model for rigid-frame porous materials with low porosity. Applied Acoustics, 58(3), 295-304. doi:10.1016/s0003-682x(98)00076-0Voronina, N. ., & Horoshenkov, K. . (2003). A new empirical model for the acoustic properties of loose granular media. Applied Acoustics, 64(4), 415-432. doi:10.1016/s0003-682x(02)00105-6Wang, X., Eisenbrey, J., Zeitz, M., & Sun, J. Q. (2004). Multi-stage regression analysis of acoustical properties of polyurethane foams. Journal of Sound and Vibration, 273(4-5), 1109-1117. doi:10.1016/j.jsv.2003.09.039Wilson, D. K. (1997). Simple, relaxational models for the acoustical properties of porous media. Applied Acoustics, 50(3), 171-188. doi:10.1016/s0003-682x(96)00048-