The land morphology approach to flood risk mapping: An application to Portugal.

In the last decades, the increasing vulnerability of floodplains is linked to societal changes such as population density growth, land use changes, water use patterns, among other factors. Land morphology directly influences surface water flow, transport of sediments, soil genesis, local climate and vegetation distribution. Therefore, the land morphology, the land used and management directly influences flood risks genesis. However, attention is not always given to the underlying geomorphological and ecological processes that influence the dynamic of rivers and their floodplains. Floodplains are considered a part of a larger system called Wet System (WS). The WS includes permanent and temporary streams, water bodies, wetlands and valley bottoms. Valley bottom is a broad concept which comprehends not only floodplains but also flat and concave areas, contiguous to streams, in which slope is less than 5%. This will be addressed through a consistent method based on a land morphology approach that classifies landforms according to their hydrological position in the watershed. This method is based on flat areas (slopes less than 5%), surface curvature and hydrological features. The comparison between WS and flood risk data from the Portuguese Environmental Agency for the main rivers of mainland Portugal showed that in downstream areas of watersheds, valley bottoms are coincident with floodplains modelled by hydrological methods. Mapping WS has a particular interest in analysing river ecosystems position and function in the landscape, from upstream to downstream areas in the watershed. This morphological approach is less demanding data and time-consuming than hydrological methods and can be used as the preliminary delimitation of floodplains and potential flood risk areas in situations where there is no hydrological data available. The results were also compared with the land use/cover map at a national level and detailed in Trancão river basin, located in Lisbon metropolitan area, an urbanized basin that suffered heavy flooding in the last decades. This study also contributes to a better understanding of the basin morphology at a local-scale and the effects of soil sealing in downstream flood risks. This work will contribute to the understanding of the morphology, ecology and land use of watersheds that could be used to reduce runoff and downstream flood risk. This can be accomplished by using natural water retention and infiltration methods or higher-level based planning instead of a reaction to local decisions on flood hazards. This morphological approach to map landforms, including wet system, is a valuable tool to assist policy makers and planners in flood risk and land use management, floodplain restoration, agricultural land management practices, and location of human activities according to ecological suitability.

The madurai intraocular lens study IV: posterior capsule opacification.

PURPOSE: To estimate the cumulative incidence of posterior capsule opacification 4 years after surgery in patients who participated in the Madurai Intraocular Lens Study and had extracapsular cataract extraction with posterior chamber intraocular lens implantation. METHODS: In the Madurai Intraocular Lens Study, 1,700 patients with best-corrected visual acuity 20/120 or worse in the better eye had extracapsular cataract extraction with posterior chamber intraocular lens implantation, and 1,474 (86.7%) of these completed the 1-year follow-up examination. From this group of 1,474 pseudophakic patients, 400 were randomly selected for reexamination 4 years after the original surgery. The eye that was operated on was examined by an ophthalmologist who was involved in the 1-year follow-up examinations and posterior capsule opacification grading. A grading of I to III was used to reflect the degree of opacification. With grades II and III, posterior capsule opacification detectable with an undilated pupil was present in the central axis. RESULTS: Three hundred twenty-seven (81.8%) of the selected population were examined between October 1997 and December 1998. Thirty-four (8.5%) were confirmed as being deceased, and 39 (9.8%) were unavailable for follow-up. The median age was 60 years, and 57.2% were women. The 4-year incidence of grade II or III posterior capsule opacification, including eyes already treated with laser capsulotomy, was 13.1% (95% confidence interval [CI], 9.7% to 17.3%). Each year of increased age was associated with a decreased risk of posterior capsule opacification (odds ratio, 0.96; 95% CI, 0.92 to 1.00). Based on best-corrected visual acuity of 20/40 or worse without co-existing pathology, the 4-year incidence of posterior capsule opacification was 13.5%. CONCLUSION: Because patients with relatively mature cataracts routinely receive extracapsular cataract extraction with posterior chamber intraocular lens implantation instead of the traditional intracapsular extraction, the subsequent need for laser capsulotomy may be less than that anticipated, based on previous reports.

Binding of endonuclease VII to cruciform DNA. Visualization in the electron microscope.

The binding of Holliday structure resolving endonuclease VII to cruciform DNA was studied in the electron microscope. The protein was found to bind either to the junction or to one of the arms or an end of one of the arms of the construct. The amount of bound protein was determined by measuring the size of the complexes. On average, one complex containing three dimers was found per one molecule of cruciform DNA.

The Madurai Intraocular Lens Study. I: A randomized clinical trial comparing complications and vision outcomes of intracapsular cataract extraction and extracapsular cataract extraction with posterior chamber intraocular lens.

PURPOSE: The Madurai Intraocular Lens Study (MIOLS) was designed to compare safety, efficacy, and quality of life outcomes after either intracapsular cataract extraction with aphakic glasses (ICCE-AG) or extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/ PC-IOL). METHODS: The Madurai Intraocular Lens Study was a nonmasked randomized controlled clinical trial conducted at a single hospital. Thirty-four hundred patients with age-related cataracts and having a best-corrected visual acuity less than or equal to 20/120 in the better eye were randomly assigned to either of the two cataract operative procedures. The main clinical outcomes were safety (complication rates) and efficacy (best-corrected visual acuity at 1 year equal to or better than 20/40). In addition, a subset of 1,700 trial participants received questionnaires before surgery, at 6 months after surgery, and at 1 year after surgery to measure visual functioning and vision-related quality of life. RESULTS: Details of study design, study organization, clinical and quality of life outcome variables, sample size calculations, patient eligibility criteria and recruitment, randomization and masking, participant flow, adherence to follow-up, quality assurance, and statistical methods are presented. CONCLUSIONS: The Madurai Intraocular Lens Study has sufficient power to detect clinically significant differences between the treatment options. There were no statistically significant differences between the two treatment groups for any of the major study variables at baseline. A high level of quality assurance was maintained throughout the October 1993 to June 1996 study period. The results should be applicable to all settings where the requisite expertise and resources are present.

The Madurai Intraocular Lens Study. II: Clinical outcomes.

PURPOSE: To evaluate the safety and efficacy of extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/PC-IOL) compared with intracapsular cataract extraction with aphakic glasses (ICCE-AG). METHODS: In a nonmasked randomized controlled clinical trial, 3,400 bilaterally vision-impaired patients aged 40 to 75 years with operable cataract were randomly assigned to receive either ICCE-AG or ECCE/PC-IOL at the Aravind Eye Hospital in India. The surgery was performed by one of four study surgeons. Patients were hospitalized for 5 postoperative days, with follow-up visits at 2, 6, and 12 months after discharge. Postsurgery evaluations were conducted by two independent study ophthalmologists. RESULTS: At any single postoperative follow-up time point, there were no statistically significant differences of clinical relevance between treatment groups for any complication of a serious nature except cystoid macular edema, which was more common with ICCE (4.2% vs 1.6%). In general, whether of a trivial, intermediate, or serious nature, complication rates were low at each evaluation time point. Cumulatively, the incidence of serious complications of all types throughout the 1-year study period was 14.5% for patients in the ICCE-AG group and 7.7% in the ECCE group (P < .001). Best-corrected visual acuity of 20/40 or better at 12 months was attained by 90.7% of ICCE-AG patients and 96.3% of ECCE/PC-IOL patients (P < .001). CONCLUSION: Although both operative procedures are safe and effective for cataract patients with bilateral impairment, ECCE/PC-IOL is superior to ICCE-AG in terms of both visual acuity restoration and safety.

Keeping an eye on vision: new tools to preserve sight and quality of life. A roundtable discussion, Part 2.

Research is pointing the way to new therapies for the eye diseases of aging. A gene that appears related to glaucoma has been identified, and a safe and effective inhibitor for aldose reductase is being sought for patients with diabetic retinopathy. Refinements in cataract surgery continue to improve the high success rate of this procedure. Physicians can educate their patients to participate in vision protection, through control of blood sugars, compliance with glaucoma medications, and the use of the Amsler grid by those at risk for macular degeneration. When vision cannot be corrected to the normal range, low vision rehabilitation offers magnification and new high-tech devices for optimizing independent patient function.

Keeping an eye on vision: primary care of age-related ocular disease. Part 1.

Normal changes in the lens, retina, and vitreous accompany aging, but loss of vision in late life is not an inevitable consequence of aging. Cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration (ARMD) account for most vision loss in the older population. Visual impairment reduces older patients' ability to function independently and increases their risk of depression and of injury due to falls. When older persons have a visual complaint, they tend to blame it on being old and do not tell their physicians. In the primary care office, simple screening questions and examination of the dilated eye can often reveal a need for further examination and/or referral.

Association of visual field, cup-disc ratio, and magnetic resonance imaging of optic chiasm.

OBJECTIVE: To assess the association of visual field, vertical cup-disc (VC/D) ratio, and vertical height of optic chiasm. DESIGN: Case series. SETTING: Outpatient eye clinic. PATIENTS: Eighteen patients with low, normal, or elevated intraocular pressure, with or without visual field defects. INTERVENTION: Measurement of visual field, VC/D ratio, and vertical height of optic chiasm. MAIN OUTCOME MEASURES: Association between VC/D ratio and visual field defects compared with association between vertical height of optic chiasm and visual field defects. RESULTS: Visual field defects were graded as 0, 1 to 10, and 11 to 20 (from least to most severe). Group mean VC/D ratios were 0.47 (0), 0.55 (1-10), and 0.69 (11-20) for right eyes and 0.48 (0), 0.57 (1-10), and 0.75 (11-20) for left eyes. The significance level for trend was P = .02 for right eyes and P = .006 for left eyes. Group mean chiasm heights were 3.5 (0), 2.9 (1-10), and 2.2 (11-20) mm for right eyes and 3.5 (0), 2.8 (1-10), and 2.2 (11-20) mm for left eyes. The significance level for trend was P < .001 for right eyes and P = .002 for left eyes. To assess the simultaneous effects of VC/D ratio and chiasm height on the visual field defects groups, we used ordinal logistic regression models. Models with both variables implied that chiasm height was a stronger predictor of visual field defects group than VC/D ratio (for right eyes, P = .04 [VC/D ratio], P = .001 [chiasm height]; for left eyes, P = .11 [VC/D ratio], P = .005 [chiasm height]). CONCLUSIONS: When chiasm and VC/D ratio were analyzed in the same model, chiasm height was a stronger predictor of visual field defects. In advanced visual field defects, the optic chiasm is atrophic.

Reactions of mitochondrial cruciform cutting endonuclease 1 (CCE1) of yeast Saccharomyces cerevisiae with branched DNAs in vitro.

Cruciform-cutting endonuclease 1 (CCE1) is an X-solvase from yeast Saccharomyces cerevisiae [Kleff, S., Kemper, B. & Sternglanz, R. (1992) EMBO J. 11, 699-704]. We report here the purification of the cloned enzyme CCE1 to near homogeneity from over-expressing Escherichia coli cells. The purified protein has a globular shape and an apparent molecular mass of 38 kDa. CCE1 reacts specifically with branched DNAs, preferably with four-armed cruciforms. The enzyme linearizes native supercoiled DNA by cutting at the base of cruciform structures as they occur in derivatives of phage M13. Supercoiling was not required for cleavage per se and a relaxed circular DNA hybrid with a stable cruciform was linearized with the same relative cleavage efficiency. Fully synthetic cruciforms (four-armed X-junctions) were also good substrates for CCE1, provided a symmetric 6-bp sequence (in our case an EcoRI restriction site) was maintained at the junction. Consequently, a synthetic cruciform made from fully randomized oligonucleotide sequences was not a substrate for CCE1. In general, cleavage sites were found clustered in a characteristic pattern in each arm of a cruciform structure. A synthetic three-armed Y-junction was also cleaved by CCE1, but with a lower efficiency than the related four-armed construct. CCE1 resolves efficiently branched synthetic DNAs in vitro. The function is consistent with the idea that CCE1 is responsible for a timely reversal of branched recombination intermediates preceding petite formation in mitochondrial DNA.

[Lipoxygenase inhibitors. IV. Synthesis and cyclization reactions of open-chain N1-aryl-substituted amidrazones]. / Lipoxygenase-Inhibitoren, 4.Mitt.1): Synthese und Cyclisierungsreaktionen offenkettiger N1-arylsubstituierter Amidrazone.

alpha-Carbonyl carboxylic acid arylhydrazonochlorides obtained by Japp-Klingemann reaction are the starting substances for the synthesis of alpha-carbonyl carboxylic acid arylhydrazonoamides, -esters and -thioesters. The inhibiting activity of these compounds against 15- and 5-lipoxygenase is described. Reactions of derivatives of amidrazones with formaldehyde give triazole, triazoline and unexpected benzotriazepine derivatives.

Strategic issues in preventing cataract blindness in developing countries.

Cataract blindness is a public health problem of major proportions in developing countries. Intracapsular cataract extraction with aphakic spectacles has been the standard surgical technique for restoring sight. Because of image magnification in the operated eye, however, the result in unilaterally blind patients is less than satisfactory. Fortunately, with the availability of low-cost intraocular lenses (IOL) and ophthalmologists trained in extracapsular surgery, it is now practical to intervene successfully in the unilateral case. The need for increased attention on the quality of the visual high prevalence of cataract blindness in developing countries and an increasing cataract incidence due to an aging population require substantial increases in surgical volume. The third issue relates to cost. If significant increases in surgical volume and quality of outcomes are to be realized without an increased need for external funding, service delivery must be made more efficient. The expansion of IOL surgery for unilateral blindness is a favourable trend in ensuring financial sustainability of delivery systems; patients can be operated on while still economically productive and able to pay rather than waiting for bilateral blindness and a less favourable economic and social impact. If the quality, volume, and cost issues are to be successfully addressed, operational and structural changes to eye care delivery systems are necessary. These changes can be effected through training, technology introduction, management of facilities, social marketing, organizational partnerships, and evaluation. With improved understanding of the critical factors in successful models their widespread replication will be facilitated.