From farmers to livestock keepers: a typology of cattle production systems in south-western Burkina Faso.

Cattle production is an essential livelihood strategy in south-western Burkina Faso. Although having a distinct cultural role and known to be resistant against African animal trypanosomosis, the Lobi taurine cattle breed is endangered due to its low market value. As the first step in preservation efforts, our study aimed to develop a typology of production systems at the farm level. We used a structured questionnaire and focus group discussions for collecting data on household characteristics, socioeconomic activities, livestock, and access to services. The sample comprised 169 households in three communities. The analytical strategy included factor analysis of mixed data and hierarchical clustering. We identified four distinct types of cattle production systems: (1) sedentary Lobi farms, (2) sedentary crossbreed farms, (3) semi-transhumant Fulani zebu farms, and (4) transhumant Fulani zebu farms. Significant factors in developing this typology were the farmers' ethnic group, crop diversity, cattle herd size, cattle herd composition, number of small ruminants, and livestock management strategies. Across all production systems, men were considered being primary decision-makers in cattle production, with women, herders, and children being responsible for specific tasks. All identified production systems are increasingly confronting disease pressure and scarcity of water and land. Future efforts in preservation and breeding will need to respond to these trends in the agroecosystem, integrate risk management measures, and resonate with the specific needs of the different household members involved in cattle rearing.

Design of a safer approach to intravenous drug infusions: failure mode effects analysis.

OBJECTIVES: A set of standard processes was developed for delivering continuous drug infusions in order to improve (1) patient safety; (2) efficiency in staff workflow; (3) hemodynamic stability during infusion changes, and (4) efficient use of resources. Failure modes effects analysis (FMEA) was used to examine the impact of process changes on the reliability of delivering drug infusions. SETTING: An 11 bed multidisciplinary pediatric ICU in the children's hospital of an academic medical center staffed by board certified pediatric intensivists. The hospital uses computerized physician order entry for all medication orders. METHODS: A multidisciplinary team characterized key elements of the drug infusion process. The process was enhanced to increase overall reliability and the original and revised processes were compared using FMEA. Resource consumption was estimated by reviewing purchasing and pharmacy records for the calendar year after full implementation of the revised process. Staff satisfaction was evaluated using an anonymous questionnaire administered to staff nurses in the ICU and pediatric residents who had rotated through the ICU. RESULTS: The original process was characterized by six elements: selecting the drug; selecting a dose; selecting an infusion rate; calculating and ordering the infusion; preparing the infusion; programming the infusion pump and delivering the infusion. The following practice changes were introduced: standardizing formulations for all infusions; developing database driven calculators; extending infusion hang times from 24 to 72 hours; changing from bedside preparation by nurses to pharmacy prepared or premanufactured solutions. FMEA showed that the last three elements of the original process had high risk priority numbers (RPNs) of >225 whereas the revised process had no elements with RPNs >100. The combined effect of prolonging infusion hang times, preparation in the pharmacy, and purchasing premanufactured solutions resulted in 1500 fewer infusions prepared by nurses per year. Nursing staff expressed a significant preference and pediatric residents unanimously expressed a strong preference for the revised process. CONCLUSIONS: Standardization of infusion delivery reduced the frequency for completing the most unreliable elements of the process and reduced the riskiness of the individual elements. Both contribute to a safer system.

Synthesis of metal-oxide matrix with embedded nickel nanoparticles by a bottom-up chemical process.

Here we describe a new chemical route for obtaining highly dispersed nanometric Ni particles embedded in different matrices based on Al2O3, MgO, and TiO2 and in the heterogeneous matrices CeO2-doped Al2O3 and MgO-doped Al2O3. The synthesis method is based on a modification of the polymeric precursor method. The Ni nanoparticles (particles in the range of 1-40 nm) were obtained in a single process, without the use of an external reducing agent (hydrogen atmosphere).

Application of Ni:SiO2 nanocomposite to control the carbon deposition on the carbon dioxide reforming of methane.

Stable Ni nanoparticles embedded in a mesoporous silica material were used as catalysts for the conversion of methane into synthesis gas. This catalyst has the singular properties of controlling the carbon deposition and deactivation of active sites. A comparative study of our nanocomposites with conventional catalysts showed that impregnation material presented a preferential encapsulation and growth of carbon nanotubes on the metal surface. The impregnated catalyst showed a higher tendency for carbon nanotube and whiskers formation.

Synthesis of mesoporous silica with embedded nickel nanoparticles for catalyst applications.

Here we describe a new route for the synthesis of nanometric Ni particles embedded in a mesoporous silica material with excellent potential for catalytic applications. Mesoporous silica with a surface area in the range of 202-280 m2/g, with narrow pore size distribution and Ni nanoparticles (particles in the range of 3-41 nm) were obtained in a direct process. A different approach was adopted to process such a nanocomposite. This new approach is based on the formation of a polymer with the silicon oxianion and nickel cation chelated to the macromolecule structure and on the control of the pyrolysis step. The CO/CO2 atmosphere resulting from the pyrolysis of the organic material promotes the reduction of the Ni citrate.

Late-onset interface keratitis after uneventful laser in situ keratomileusis.

Although there have been many proposed etiologies for interface inflammation after laser in situ keratomileusis, the causative factor(s) remains an enigma. This case of late-onset interface inflammation suggests that the many previously suspected interface contaminants from the surgical environment were not involved. Transformation of a previously inert material to an inflammatory stimulus is proposed as a potential cause; however, a sample of inflammatory focus was not obtained because of the immediate and complete response to frequent topical steroid drops.

Combined refractive lensectomy and laser in situ keratomileusis to correct extreme myopia.

Refractive lensectomy followed by laser in situ keratomileusis (LASIK) was performed in both eyes of a severely myopic patient. An uncorrected visual acuity of 20/20 was achieved in the right eye with a manifest refraction of plano -0.25 x 65. Intentional monovision correction of the left eye left a manifest refraction of -0.75 diopter. Best corrected visual acuity improved by 1 Snellen line to 20/20 in both eyes. Follow-up evaluation will be required to assess the long-term refractive stability and the incidence of retinal detachment after combined refractive lensectomy and LASIK.

Novel assay for Roberts syndrome assigns variable phenotypes to one complementation group.

Roberts syndrome (RS) is a rare autosomal recessive disorder characterized by heterogeneous clinical features, the most notable being tetraphocomelia, cleft lip, and cleft palate. Cells derived from most RS patients exhibit abnormal cytogenetic and cellular phenotypes that include the premature separation of para- and pericentromeric heterochromatin visible on C-banded metaphase chromosomes, a phenomenon referred to as heterochromatic splaying. Previously, it was shown that these abnormal phenotypes can be complemented following somatic cell hybridization between RS cells and control cells. In the current study, a permanent cell line was established from a new RS patient with a more severe phenotype than represented by previously established cells in culture. With a newly developed assay designed to facilitate rapid evaluation of in vitro complementation, we assigned this new patient to the same genetic complementation group defined by other, less severely affected patients. The results demonstrate that a single complementation group defines RS patients with heterochromatic splaying regardless of clinical severity.

Central corneal thickness in low-tension glaucoma.

BACKGROUND: It is possible that the intraocular pressure (IOP) is underestimated in eyes whose central cornea is thinner than normal. The objective of this study was to determine and establish the significance of central corneal thickness in patients with low-tension (normal-tension) glaucoma compared with those with chronic open-angle glaucoma (COAG) or ocular hypertension and healthy eyes. METHODS: The study was carried out from February 1998 to May 1999. Central corneal thickness was measured by ultrasonic pachymetry and IOP was measured by Goldmann applanation tonometry in 25 patients with low-tension glaucoma (untreated IOP less than 21 mm Hg with evidence of optic nerve head damage and corresponding visual field loss on automated perimetry), 80 patients with COAG (untreated IOP 21 mm Hg or greater with evidence of optic nerve head damage and corresponding visual field loss on automated perimetry), 16 patients with ocular hypertension (untreated IOP 21 mm Hg or greater, with normal optic nerve head and no history of glaucoma or elevated IOP, and normal visual field on automated perimetry) and 50 control subjects (untreated IOP less than 21 mm Hg with normal optic nerve head and no history of glaucoma or elevated IOP). Analysis with Pearson's product-moment correlation was performed to determine the correlation of IOP and central corneal thickness, and one-way analysis of variance was used to compare corneal thickness between groups. RESULTS: The central cornea was significantly thinner in the low-tension glaucoma group (mean 513.2 mu [standard deviation (SD) 26.1 mu]) than in the COAG group (mean 548.2 mu [SD 35.0 mu]) and the control group (mean 556.7 mu [SD 35.9 mu]) (p < 0.001). No significant difference in corneal thickness was found between the COAG and control groups. The ocular hypertension group had significantly thicker corneas (mean 597.5 mu [SD 23.6 mu]) than the three other groups (p < 0.001). INTERPRETATION: Patients with low-tension glaucoma may have thinner corneas than patients with COAG and healthy subjects. This results in underestimation of their IOP. Corneal thickness should be taken into account when managing these patients to avoid undertreatment.

Pseudo-Fleischer ring after hyperopic laser in situ keratomileusis.

A 37-year-old woman had bilateral hyperopic laser in situ keratomileusis (LASIK). Six months postoperatively, an epithelial pigmentation ring pattern was identified on both corneas. The appearance of the ring pattern was similar to the iron deposits of the Fleischer ring of keratoconus. While corneal iron deposits in various patterns have been reported after other forms of ocular therapeutic and refractive surgery, this is the first report of the association between hyperopic LASIK and a corneal iron line, which we have called the "pseudo-Fleischer ring."

The member satisfaction survey as a measure of health plan accountability.

In its 1996 study of St. Louis area health maintenance organization members, Gateway Purchasers for Health closely analyzed member responses to the National Committee for Quality Assurance's annual member health care survey. The analysis of specific questions regarding overall satisfaction levels and member health status afforded insight into the factors that contribute to an individual's reported satisfaction with health care services and into variations by subgroups within the population. Ultimately, consumer information that allows choice of a health plan that best suits specific needs and preferences will drive accountability, quality, and value in the health care market.

Correlation of intraocular pressure and central corneal thickness in normal myopic eyes and after laser in situ keratomileusis.

PURPOSE: To determine the relationship of intraocular pressure (IOP) and central corneal thickness (CCT) in normal myopic eyes and after laser in situ keratomileusis (LASIK). SETTING: TLC The Windsor Laser Center, Windsor, Ontario, Canada. METHODS: Intraocular pressure measured by Goldmann applanation tonometry and CCT by ultrasonic pachymetry were determined in a group of untreated corneas of 120 patients (203 eyes) and in 50 patients (85 eyes) pre- and post-LASIK. Statistical analyses were performed with the Pearson correlation coefficient and paired Student t test. RESULTS: In the untreated group of 288 eyes, mean CCT was 544.0 microns +/- 37.3 (SD) (range 461 to 664 microns) and mean IOP, 15.6 +/- 2.7 mm Hg (range 10 to 24 mm Hg). The correlation between IOP and CCT in this group was highly significant (r = 0.44; P < .0001). The slope was 0.032 mm Hg/micron of CCT or an approximate decrease of 1 mm Hg, for a reduction in CCT of 31.3 microns. In the post-LASIK group, mean CCT dropped approximately 73.0 microns to 479.5 +/- 41.2 microns (range 408 to 503 microns) and IOP dropped to a mean of 13.6 +/- 3.3 mm Hg (range 7 to 22 mm Hg). A significant correlation was found between IOP and CCT after LASIK (r = 0.33; P < .002). The difference between the mean pre- and post-LASIK measurements of applanation IOP was 2.5 mm Hg, which was significant (P < .0001). The post-LASIK slope was 0.027 mm Hg/micron, or a decrease of 1.0 mm Hg per 37.8 microns reduction in CCT. CONCLUSION: Central corneal thickness is an important variable in the evaluation of applanation IOP and should be included in the assessment of any case of potential glaucoma or ocular hypertension, particularly in eyes with previous photoablative refractive surgery.

Removal of flap striae following laser in situ keratomileusis.

While laser in situ keratomileusis (LASIK) offers advantages over photorefractive keratectomy (PRK), creation of the corneal flap has been associated with postoperative flap striae. These result from misalignment of the corneal flap after flap replacement, movement of the corneal flap during the first postoperative day, or the "tenting effect" of the corneal flap over the ablated stromal bed. Flap striae become more difficult to remove as the postoperative course progresses; therefore, identifying the striae on the first postoperative day is imperative. We describe techniques of flap hydration, refloating, stretching, and smoothing that we use to remove visually significant flap striae.

Mathematics of laser in situ keratomileusis for high myopia.

PURPOSE: To determine the maximal ablation that can be safely performed with laser in situ keratomileusis (LASIK) to maintain long-term corneal integrity. SETTING: TLC The Windsor Laser Center, Windsor, Canada. METHODS: The pretreatment protocols for the VISX Star, Summit Omnimed, and Chiron Technolas 116 excimer lasers generally apply 1 to 2 microns per diopter (D) at an optical zone of 3.0 mm or less to avoid the postoperative central islands that can occur with broad-beam excimer lasers. The ablation depth per diopter for the VISX Star, Summit Omnimed, Chiron Technolas 116, and Chiron Technolas 217 excimer lasers ranges from 10 to 24 microns per diopter depending on the size and number of ablation zones and the excimer laser used. RESULTS: Previous experience with lamellar surgery suggests that at least 250 microns of central posterior stromal tissue should be preserved to maintain long-term corneal integrity and avoid postoperative corneal ectasia. If a 160 microns flap is created for LASIK, the average 550 microns cornea will have 140 microns of corneal stroma available for ablation. Depending on the excimer laser and ablation nomogram used, the maximal LASIK correction for the average cornea ranges from 9.8 to 15.0 D. CONCLUSION: The preoperative corneal thickness and the depth of the excimer laser ablation must be evaluated before LASIK to ensure that adequate posterior corneal stroma is preserved.

Conservative photorefractive keratectomy for residual myopia following radial keratotomy.

OBJECTIVE: To evaluate the efficacy, predictability, stability and safety of a conservative approach to photorefractive keratectomy (PRK) (treating only 60% to 70% of the residual myopia) for residual myopia following radial keratotomy (RK). DESIGN: Case series. SETTING: Laser eye surgery centre in Windsor, Ont. PATIENTS: Thirty-three eyes of 27 patients with an average age of 40.1 years who underwent PRK between January 1993 and July 1995, 12 months or more after RK. All were followed for at least 12 months after PRK. OUTCOME MEASURES: Efficacy and safety were assessed by changes in the uncorrected and best corrected visual acuity. Predictability was determined by the proximity of the final result to emmetropia. The stability of the refractive outcome was assessed over the follow-up period. RESULTS: At 12 months 12 eyes (36%) had 20/20 or better uncorrected visual acuity and 29 eyes (88%) had 20/40 or better uncorrected acuity. Twenty-seven eyes (82%) were within 0.50 D of emmetropia, and 30 eyes (91%) were within 1.00 D of emmetropia. There was a significant change in the mean postoperative spherical equivalent between 1 and 3 months (p < 0.001); however, there was no significant change after this time. Six eyes (18%) had a loss of 2 or more lines of best corrected visual acuity due to corneal haze; however, retreatment reduced this incidence to 9% at 12 months. CONCLUSIONS: Our results show that conservative PRK for residual myopia following RK is efficacious and predictable and produces stable results. However, the risk of postoperative haze reduces the safety of this procedure.

Argon laser punctal therapy versus thermal cautery for the treatment of aqueous deficiency dry eye syndrome.

BACKGROUND: The objective of this prospective randomized study was to compare the safety and efficacy of argon laser punctal ablation and electrocautery punctal occlusion in the treatment of moderate to severe dry eye and to correlate standard clinical signs with symptoms in these patients. METHODS: From June 1996 to April 1997 we studied 32 patients (64 eyes) referred to a university-affiliated tertiary care hospital with signs or symptoms of dry eye. Moderate to severe dry eye was confirmed by means of the Schirmer 1 test, fluorescein and rose bengal staining and a visual analogue scale measure of six subjective symptoms. Patients with severe dry eye were randomly assigned to undergo argon laser ablation (17 eyes) or electrocautery occlusion (18 eyes), and were reassessed 2 weeks, 1 month and 6 months after treatment. RESULTS: Compared with baseline, the laser-treated patients had a peak improvement of 40% in surface wetting at 1 month and improvement of 33% at 6 months; the peak improvement at 6 months in the electrocautery group was 84% (p < 0.05). At 6 months the laser group had a twofold reduction in rose bengal staining, compared with a sevenfold reduction in the electrocautery group (p < 0.05). The electrocautery group had the greatest decrease in fluorescein staining at 6 months (2.8-fold vs. twofold) (p < 0.05). The laser group reported a reduction in symptoms of 31% at 1 month and 14% at 6 months; the corresponding values for the electrocautery group were 55% and 64% (p = 0.02). Posttreatment epiphora was insignificant in both groups. In patients with surface wetting of more than 5 mm at baseline, regular use of Tear-Gel resulted in both objective and subjective improvement. INTERPRETATION: Although argon laser punctal ablation is a safe method of treating aqueous tear deficiency states, with minimal side effects, both subjective and objective improvement were greater with electrocautery punctal occlusion. Intensive use of Tear-Gel offers benefit to patients with debilitating symptoms in whom aqueous tear production is not severely reduced.