Pérdida de células endoteliales después de cirugía de catarata por facoemulsificación

Objetivo: Determinar la pérdida celular endotelial corneal posterior a la cirugía de catarata por técnica de facoemulsificación. Métodos: Se realizó un estudio descriptivo de intervención prospectivo y longitudinal. Se estudiaron 51 ojos operados de catarata por la técnica de facochop. Se les realizó microscopia endotelial pre- y posoperatoria a los tres y seis meses de la intervención. También se estudiaron los parámetros facodinámicos. Resultados: La edad promedio fue de 66,7 ± 11,7 años, predominó el sexo femenino (53,7 %). Se observó una disminución significativa de los valores promedios de densidad celular y hexagonalidad a los tres y seis meses posteriores a la operación de catarata. El porcentaje de pérdida de células endoteliales posterior a la intervención fue de 19,6 ± 0,8 %. El tiempo total de ultrasonido medio fue de 11,8 ± 4,5 seg mientras el tiempo efectivo de facoemulsificación tuvo una media de 0,008 ± 0,001 seg. Conclusiones: El recuento de células endoteliales corneales muestra una disminución significativa de los valores promedios de densidad celular y hexagonalidad a los tres y seis meses posteriores a la operación de catarata, el porcentaje de pérdida de células endoteliales corneales a los seis meses posterior está dentro de los límites normales y se observa relación de dependencia entre el tiempo efectivo de facoemulsificación y el porcentaje de pérdida de células endoteliales.

Objective: To determine the loss of corneal endothelial cell after cataract surgery by the phacoemulsification technique. Methods: A prospective, longitudinal, descriptive and interventional study was conducted. Fifty-one eyes operated on for cataract by the phacoemulsification technique were studied. Preoperative, as well as postoperative endothelial microscopy at three and six months after the cataract surgery, was performed. Phacodynamic parameters were also studied. Results: The mean age was 66.7 ± 11.7 years and there was a predominance of the female sex (53.7%). A significant decrease in the mean values of cell density and hexagonality was observed at three and six months after the cataract surgery. The percentage of endothelial cell loss after surgery was 19.6% ± 0.8%. The mean total ultrasound time was 11.8 ± 4.5 secs, while the effective phacoemulsification time had a mean of 0.008 ± 0.001 secs. Conclusions: The count of corneal endothelial cell shows a significant decrease in the mean values of cell density and hexagonality at three and six months after the cataract surgery; the percentage of corneal endothelial cell loss at six months is within normal limits; and a dependent relationship is observed between the effective phacoemulsification time and the percentage of endothelial cell loss.

Similarity-Based Predictive Models: Sensitivity Analysis and a Biological Application with Multi-Attributes.

Predictive models based on empirical similarity are instrumental in biology and data science, where the premise is to measure the likeness of one observation with others in the same dataset. Biological datasets often encompass data that can be categorized. When using empirical similarity-based predictive models, two strategies for handling categorical covariates exist. The first strategy retains categorical covariates in their original form, applying distance measures and allocating weights to each covariate. In contrast, the second strategy creates binary variables, representing each variable level independently, and computes similarity measures solely through the Euclidean distance. This study performs a sensitivity analysis of these two strategies using computational simulations, and applies the results to a biological context. We use a linear regression model as a reference point, and consider two methods for estimating the model parameters, alongside exponential and fractional inverse similarity functions. The sensitivity is evaluated by determining the coefficient of variation of the parameter estimators across the three models as a measure of relative variability. Our results suggest that the first strategy excels over the second one in effectively dealing with categorical variables, and offers greater parsimony due to the use of fewer parameters.

Assessing thermal adaptation of a global sample of Aspergillus fumigatus: Implications for climate change effects.

Aspergillus fumigatus is a common environmental mold and a major cause of opportunistic infections in humans. It's distributed among many ecological niches across the globe. A major virulence factor of A. fumigatus is its ability to grow at high temperature. However, at present, little is known about variations among strains in their growth at different temperatures and how their geographic origins may impact such variations. In this study, we analyzed 89 strains from 12 countries (Cameroon, Canada, China, Costa Rica, France, India, Iceland, Ireland, New Zealand, Peru, Saudi Arabia, and USA) representing diverse geographic locations and temperature environments. Each strain was grown at four temperatures and genotyped at nine microsatellite loci. Our analyses revealed a range of growth profiles, with significant variations among strains within individual geographic populations in their growths across the temperatures. No statistically significant association was observed between strain genotypes and their thermal growth profiles. Similarly geographic separation contributed little to differences in thermal adaptations among strains and populations. The combined analyses among genotypes and growth rates at different temperatures in the global sample suggest that most natural populations of A. fumigatus are capable of rapid adaptation to temperature changes. We discuss the implications of our results to the evolution and epidemiology of A. fumigatus under increasing climate change.

Marandu grass pastures with the same average height and different horizontal structures change the feeding behavior of grazing sheep? / Pastos de capim-marandu com mesma altura média e diferentes estruturas horizontais alteram o comportamento ingestivo de ovinos em pastejo?

The objective was to investigate the feeding behavior of sheep in marandu grass (Brachiaria brizantha cv. Marandu) pastures under continuous stocking with the same average height and different horizontal structures. The treatments were composed of less heterogeneous pastures (P-H, 24% coefficient of variation of plant heights and more heterogeneous pastures (P+H, 46% coefficient of variation of plant heights) and the locations of the picket, front and back, were also evaluated. A randomized block design was used, with split plots in space and four replications in two years. Crossbred lambs were used, managed under continuous stocking and variable stocking rate, to maintain average height of pastures at 30 cm. Greater masses of total forage, live leaf, live stem and dead material, and greater time of sheep in rumination, occurred in the front, in relation to the paddock background. In P-H, grazing time (GT) did not vary between regions. In P+H, GT was lower at the front than at the background. Idle time (IT) was similar between P-H and P+H. However, the animals remained more IT in the front than in the background. The feeding behavior of grazing sheep is modified in marandu grass pastures under continuous stocking with the same average height, but with different spatial variability of the vegetation.

Objetivou-se investigar o comportamento ingestivo de ovinos em pastos de capim-marandu (Brachiaria brizantha cv. Marandu) sob lotação contínua com mesma altura média e diferentes estruturas horizontais. Os tratamentos foram compostos de pastos menos heterogêneo (P-H, 24% de coeficiente de variação das alturas das plantas) e pastos mais heterogêneo (P+H, 46% de coeficiente de variação das alturas das plantas), também foi avaliado os locais do piquete, frente e fundo. O delineamento utilizado foi de blocos ao acaso, com parcelas subdivididas no espaço e quatro repetições em dois anos. Foram utilizadas borregas mestiças, manejadas sob lotação continua e com taxa de lotação variável, para manter altura média dos pastos em 30cm. Maiores massas de forragem total, folha viva, colmo vivo e material morto, e maior tempo dos ovinos em ruminação, ocorreram na frente, em relação ao fundo do piquete. No P-H, o tempo em pastejo (TP) não variou entre as regiões. No P+H, o TP foi menor na frente do que no fundo. O tempo em ócio (TO) foi semelhante entre os P-H e P+H. Porém, os animais permaneceram mais TO na frente que no fundo. O comportamento ingestivo de ovinos em pastejo é modificado em pastos de capim-marandu sob lotação contínua com mesma altura média, porém com diferentes variabilidades espaciais da vegetação.

Residual formaldehyde contents in fresh white cheese in El Salvador: Seasonal changes associated with temperature.

Detection of residual formaldehyde (FA) in dairy products could be explained by direct addition of this preservative to extend the shelf life of raw material or final product at room temperature. FA is not authorized as a preservative by international standards and its addition to dairy products is prohibited due to its potentially harmful effects on consumers. Although the carcinogenicity of FA by oral exposure has not been proven, it is also known it cause histopathological and cytogenic changes in tissues at first contact, so its toxicity by ingestion should not be underestimated. This research determined both residual FA levels in locally produced fresh white cheese and its variation according to the seasons of the year and its association with ambient temperature. None of the FA levels quantified in cheese exceeded the maximum tolerable concentration (2.6 mg/kg) and although average FA contents did not vary significantly with seasonal changes (0.093-0.181 mg/kg), the number of positive cases did, since the highest prevalence occurred in the dry (60.9 %) and transitional dry-rainy (79.7 %) seasons of 2021, which are characterized by having the highest average ambient temperatures (27.5 °C and 28.3 °C, respectively). It was also shown that 79.6 % of the variability of FA-positive samples is explained by changes in the average temperature according to the year´s season. The association between these variables and quantified levels of aldehyde in raw milk sampled at the plant could indicate that FA was used to prevent milk and/or the final product from decomposing due to the effect of high ambient temperature. In addition, residual FA contents decreased in both milk and cheese, depending on added preservative levels, and the time elapsed prior to analysis.

Comportamiento espacial de indicadores fisicoquímicos y calidad del suelo en plantación de Theobroma cacao en Padre Abad, Ucayali, Perú

El cultivo de cacao en el trópico peruano presenta bajos rendimientos, lo que exige buscar alternativas para aumentar la producción. Frente a esta situación, los estudios geoespaciales facilitan el diagnóstico de fertilidad y la aplicación de planes de fertilización. Por lo tanto, se evaluó la distribución espacial de indicadores fisicoquímicos y calidad del suelo en Padre Abad, región Ucayali, Perú. Se evaluaron indicadores fisicoquímicos y la calidad del suelo y se sometieron al análisis geoestadístico, a través del interpolador Kriging, encontrándose coeficientes de variación bajos para arcilla, pH y potasio K y medios para arena, limo, materia orgánica (MO), nitrógeno (N), fósforo (P), potasio (K+), calcio (Ca2+), magnesio (Mg2+), aluminio (Al3+), capacidad de intercambio de cationes (CIC), saturación de bases (SB), acidez cambiable (AC) y saturación de aluminio (SAl). La calidad del suelo varió entre baja a muy baja, con una distribución espacial de 52,24 y 47,76 %. El análisis de componentes principales encontró significancia para arena, limo, MO, N, K+, Al3+, CIC, %AC, %BC y %SAl, todos presentan variación espacial, según su nivel de fertilidad, excepto K+. Los modelos de interpolación con mejores ajustes fue el exponencial y lineal con dependencia espacial fuerte para arena, limo y K, moderada para MO, N, Al, CIC, %SAl e índice de calidad del suelo y débil para %BC y %AC, con una eficiencia de predicción confiable. Se encontró alta variabilidad espacial con valores medios de los diferentes indicadores de fertilidad bajos, no favorables para el desarrollo del cultivo de cacao.

Cocoa cultivation in the Peruvian tropics has low yields, which requires seeking alternatives to increase the production. Faced with this situation, geospatial studies facilitate the diagnosis of fertility and the efficient application of fertilization plans. Therefore, the spatial distribution of physicochemical indicators and soil quality in Padre Abad, Ucayali region, Peru were evaluated. Physicochemical indicators and soil quality were evaluated and subjected to geostatistical analysis through the Kriging interpolator, finding low coefficients of variation for clay, pH and potassium (K+), and medium for sand, silt, organic matter (OM), nitrogen (N), phosphorus (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+), aluminum (Al3+), cation exchange capacity (CEC), base saturation (BS), exchangeable acid (EA) and aluminum saturation (AlS). Soil quality ranged from low to very low quality with a spatial distribution of 52.24 % and 47.76 % respectively. Principal component analysis found significance for sand, silt, OM, N, K+, Al3+, CEC, %EC, %BS and %AlS, all showing spatial variation according to their fertility level, except K+. The interpolation models with best fits were the exponential and linear with strong spatial dependence for sand, silt and K, moderate for MO, N, Al, CEC, %AlS and soil quality index (SQI), and weak for %BS and %EC, with reliable prediction efficiency. The research found high spatial variability with low mean values of the different fertility indicators, not favorable for cocoa crop development.

How does the initial sward height and the grazing period influence the spatial variability of vegetation in deferred signal grass pastures?

The objective of this study was to evaluate the spatial variability of structural characteristics of deferred pastures of Brachiaria decumbens cv. Basilisk (signal grass) subjected to associations of sward heights (10, 20, 30, and 40 cm) at the beginning of deferment and grazing periods (1, 28, 56, 85, and 113 days). The experiment was arranged in a split-plot and completely randomized-block design with two replicates. Pastures remained deferred from March to June 2010. From June to the beginning of October 2010, deferred pastures were utilized by steers under continuous grazing and at a fixed initial stocking rate of 3.5 AU ha-1. At the beginning of the deferment, the coefficient of variation (CV) for pasture height was reduced linearly with the pasture height. During the grazing period, in the winter, the CV for pasture height was not influenced by initial pasture height; however, it responded quadratically to the grazing period, with a maximum value of 36.4% at 71 days of the period of utilization. The CV for tiller height was reduced linearly with pasture height at the beginning of deferment but increased linearly along with the grazing period. The initial pasture height did not change the CV of the falling index. However, the latter was quadratically influenced by the grazing period, with a maximum value of 59.5% at 67 days of the utilization period. Signal grass pastures deferred at a lower height have a higher spatial variability of the vegetation. In the grazing period, there are changes in the spatial variability of the vegetation of the deferred signal grass.

Individual variation in the advertisement call of Aplastodiscus albosignatus (Anura: Hylidae) is correlated with body size and environmental temperature

The importance of amphibian bioacoustics is widely documented in ecological, taxonomical and evolutionary studies, as calls might act as a primary mechanism of reproductive isolation. The influence of air temperature and male size on the variation of the advertisement calls in anurans is widely recognized but still insufficiently analyzed in Brazilian species. Our goals were to (1) describe the advertisement call of Aplastodiscus albosignatus (Lutz & Lutz, 1938), (2) test the influence of temperature and body size on its acoustic signals and (3) evaluate the variation of within and between-male acoustic signals. Advertisement calls of A. albosignatus consist of an unpulsed note with four harmonics. In most cases, the dominant frequency is the third harmonic but, in some calls, it was the minimum frequency (first harmonic). The average duration of calls was 0.191 s, the interval between calls was 2.08 s and the repetition rate was 33 calls per minute. On average, the minimum frequency was 550.15 Hz, the maximum frequency was 3531.70 Hz and the third harmonic was 2498.9 Hz. To evaluate the effect of air temperature, and body size on the variation of call parameters, we performed generalized linear models. The most explanatory model for spectral parameters was temperature plus body size. Concerning temporal variables, the best model that explains the variation in call duration was body size, while for the interval between calls was air temperature. The maximum frequency and the frequency of the third harmonic had little variation in the calls of both the same male and different males. Thus, these parameters were considered important in species recognition.(AU)

Validation of a simple liquid chromatography coupled to tandem mass spectrometry method for the simultaneous determination of tacrolimus, sirolimus, everolimus and cyclosporin A in dried matrix on paper discs.

INTRODUCTION: Due to its high specificity and sensitivity, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is the gold standard method for immunosuppressant quantification in therapeutic drug monitoring. In this context, dried blood spots (DBS) have become a promising strategy as a sample collection procedure. Although the advantages of DBS over venipuncture are well known, this approach has limitations that strongly influence the acceptance of analytical results. Among them, the most important is hematocrit (Ht). The easiest way of overcoming this problem is by analyzing complete spots. In this strategy, called dried matrix on paper discs (DMPD), blood is volumetrically applied on pre-punched discs. OBJECTIVES: To validate an LC-MS/MS method for the quantification of tacrolimus, sirolimus, everolimus and cyclosporin A using DMPD. METHODS: The procedure was validated according to international guidelines using a commercial kit. The following performance parameters were evaluated: selectivity, carryover, linearity, accuracy, precision, lower limit of quantitation, relative recovery, commutability and stability. In addition, a method comparison study was performed to evaluate the clinical influence of Ht on the results. RESULTS: All performance parameters were within acceptance criteria and, hence, it was determined that the validated method is fit for the intended purpose. Likewise, calculated bias values on medical decision levels showed that there was no clinical influence of Ht on the results. CONCLUSION: Unlike other similar methodologies that have been published, here, a simple method has been fully validated. This is the first LC-MS/MS methodology adapting a commercial kit to use DMPD as a sampling strategy.

Evaluating a Muscle Ultrasound Education Program: Theoretical Knowledge, Hands-on Skills, Reliability, and Satisfaction of Critical Care Physiotherapists.

OBJECTIVE: To evaluate learning results of critical care physiotherapists participating in a muscle ultrasound (MUS) educational program. DESIGN: Cross-sectional study. SETTING: A custom-made 20-hour MUS course was performed over a 2-week time period, including knobs familiarization, patient positioning, anatomic landmarks, image acquisition, and limb muscle measurements. PARTICIPANTS: Nineteen critical care physiotherapists with little to no prior experience in ultrasound (N=19). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Theoretical knowledge, hands-on skills acquisition, and satisfaction were assessed. Inter- and intrarater reliability on landmarks, thickness, and pennation angle of quadriceps between participants was evaluated using intraclass correlation coefficients (ICCs). Reliability among instructors measured prior to the course was also reported as a reference. RESULTS: The percentage score (mean±SD) of knowledge questionnaires was 69±11 (pre-course), 89±10 (post-course), and 92±9 (hands-on skills). Course satisfaction scores ranged from 90%-100%. Pooled interrater reliability of participants (median ICC [interquartile range]) was good (0.70 [0.59-0.79]) for thickness, moderate (0.47 [0.46-0.92]) for landmarks, and absent (0.00 [0.00-0.05]) for pennation angle and the intrarater reliability was good (0.76 [0.51-0.91]) for thickness and weak (0.35 [0.29-0.52]) for pennation angle. Interrater ICC values for instructors were excellent (0.90) for thickness, good (0.67) for landmarks, and moderate (0.41) for pennation angle and intrarater ICC values were excellent (0.94) for thickness and good (0.75) for pennation angle. CONCLUSIONS: Although our sample was quite small and homogeneous, increased theoretical knowledge, high hands-on performance acquisition, and good satisfaction of physiotherapists were observed. Reliability was moderate to excellent for thickness and landmarks and absent to weak for pennation angle. Landmarking and pennation angle remain challenges for physiotherapist training in the application of MUS. Further studies are needed to identify variables that could modify reliability during MUS training.

Comparative performances of seven quantitative Reverse-Transcription Polymerase Chain Reaction assays (RT-qPCR) for detecting SARS-CoV-2 infection in samples from individuals suspected of COVID-19 in São Paulo, Brazil.

Introduction: Brazil is the second largest country with COVID-19 positive cases worldwide. Due to the potent spread of the virus and the scarcity of kits and supplies, the Brazilian Ministry of Health has granted authorization for the use of kits available during this emergency, without an accurate evaluation of their performance. This study compared the performance and cost-effectiveness of seven molecular assays/kits available in São Paulo, Brazil, for SARS-CoV-2 diagnosis. Materials and methods: A total of 205 nasopharyngeal/oropharyngeal samples from suspected cases of COVID-19, were tested using the following assays: (i) GeneFinder COVID-19 plus RealAmp kit; (ii) 2019-nCoV RNA PCR-Fluorescence Probing, Da An Gene Co.; (iii) in-house RT-qPCR SARS-CoV-2 IAL; (iv) 2019-nCoV kit, IDT; (v) molecular SARS-CoV-2 (E) kit, Bio-Manguinhos; (vi) Allplex 2019-nCoV modified Assay, Seegene Inc, and (vii) Biomol one-step COVID-19 kit, IBMP. The criteria for determining a SARS-CoV-2 true positive result included the cycle threshold cut-off values, the characteristics of exponential/linear curves, the gene target diversity, and a positive result in at least two assays. Results: The overall sensitivity of the assays listed were GeneFinder 83.6%, Da An Gene 100.0%, IAL 90.4%, IDT 94.6%, Bio-Manguinhos 87.7%, Allplex 97.3%, and IBMP 87.7%. The minor sensitive gene target was RdRP. Although all assays had a Cohen's Kappa index ≥0.893, the best tests used multiplex assays identifying N-gene and/or E-gene targets. Conclusion: All assays tested accurate for diagnosis, but considering cost-effectiveness (cost, time consumption, number of samples tested, and performance), the in-house IAL assay was ideal for COVID-19 diagnosis in São Paulo, Brazil.

Aflatoxin M1 in Nicaraguan and locally made hard white cheeses marketed in El Salvador.

Aflatoxin M1 is a carcinogenic and genotoxic metabolite of Aflatoxins present in food contaminated by fungi for lactating cattle, it is excreted through milk and when used to make cheese, the toxin will also be transferred to the dairy. The contamination of unripened hard white cheese with AFM1 seems to vary according to the season of the year, possibly due to the change of foodstuff, from fresh pasture in the rainy season to dried foods in the dry season and vice versa. This research determined both the prevalence and contents of AFM1 in cheeses of local and Nicaraguan origin marketed in El Salvador, as well as the changes occurred according to the season and the association between levels of AFM1 with meteorological parameters. The significantly higher prevalence of AFM1 contamination in both local cheeses and Nicaraguans, was found in the dry season and the lowest in the rainy season (41 % vs. 20 %; 31 % vs. 0%, respectively), the same trend was observed in AFM1 contents (0.076 vs. 0.036 µg/kg; 0.050 vs. 0.021 µg/kg, respectively). A significant association was demonstrated between levels of AFM1 with the averages of accumulated rainfall and relative humidity according to the sampled season. The prevalence of AFM1 in cheeses indicate that El Salvador and Nicaragua are endemic to dairy contamination by that mycotoxin. Seasonal variation may be due to a lack of rainfall, that promotes the growth of aflatoxigenic fungi in the crops of raw materials, which will be used for feedstuff intended for dairy cattle, thus, the consumption of contaminated food will cause the temporary increase of AFM1 in milk and their derivatives.

Genetic study of litter size and litter uniformity in Landrace pigs

We aimed to estimate litter size and litter uniformity genetic parameters and genetic trends of Landrace pigs at birth and at three weeks by using multitrait analyses for 2,787 litters. The following litter traits were evaluated: number of piglets born alive (NBA), within-litter weight mean at birth (MBW), within-litter weight standard deviation at birth (SDB), within-litter weight coefficient of variation at birth (CVB), number of piglets at three weeks (NT), within-litter weight mean at three weeks (MT), within-litter weight standard deviation at three weeks (SDT), and within-litter weight coefficient of variation at three weeks (CVT). Heritability estimates for NBA, MBW, SDB, and CVB were 0.09±0.04, 0.31±0.08, 0.01±0.04, and 0.07±0.05, respectively, greater than those obtained at three weeks (0.06±0.04, 0.10±0.06, 0.01±0.04, and 0.02±0.04 for NT, MT, SDT, and CVT, respectively). The genetic correlations between NBA and MBW and between MBW and CVB (−0.73±0.20 and −0.93±0.21, respectively) were of moderate to high magnitudes, as well as the genetic correlations between CVT and SDT (0.85±0.39). Genetic correlations between MBW and MT, SDB and SDT, CVB and CVT, and NBA and NT were 0.73±0.16, 0.69±0.54, 0.36±0.80, and 0.95±0.06, respectively. The genetic trends were linear for NBA and CVB and quadratic for MBW and SDB, whereas for all traits at three weeks, they were close to zero. Within-litter weight coefficient of variation (CV) may be the most appropriate variation measure for application in breeding programs, especially at birth, due to its greater heritability estimate and high and negative genetic correlation with MBW. The genetic trends show that NT does not follow the increase in NBA, emphasizing the need to review the breeding goals.(AU)

Relationship between cotton productivity and variability of NDVI obtained by landsat images / Relação entre produtividade do algodoeiro e variabilidade do NDVI obtido por imagens do landsat

The availability of satellite images has generated a large number of regional and global studies on vegetation mapping. Such studies have related the growth parameters, nutrient status, physiological responses, and water resources to the yield of agricultural crops or native vegetation. The NDVI (Normalized Difference Vegetation Index) is associated with parameters of growth and yield with readings at several moments of the crop cycle. The objective of this work was to correlate the yield and variability of the NDVI in cotton fields by analyzing Landsat satellite images acquired over nine growing seasons. The study involved the analysis of 101 cotton production fields located in West-Central Brazil. One Landsat image was used during each crop cycle, and the average yield was computed based on total fiber harvested at each field. The fiber yield ranged from 393 to 2,030 kg ha-1, and its correlation with NDVI was 0.37. The coefficient of variation (CV) had a negative correlation with yield, approximating -58.1 kg ha-1 for every one percent increment of the CV. The CV explained the yield variability over the cotton fields more accurately than the average absolute NDVI value.

Desde a disponibilização das imagens de satélites, tem-se gerado grande número de estudos regionais e globais para caracterizar a vegetação. Esses estudos têm relacionado parâmetros de crescimento, nutricionais, fisiológicos, hídricos e produtividade das culturas agrícolas ou vegetação nativa. O NDVI (Normalized Difference Vegetation Index) é associado com parâmetros de crescimento e produtividade do algodoeiro com leituras em vários momentos do ciclo. O objetivo desse trabalho foi relacionar a variabilidade do NDVI em campos de produção de algodão e a produtividade pelo uso de imagens do satélite Landsat ao longo de nove safras. O estudo foi desenvolvido com análise de 101 campos de produção localizados na região central do Brasil. Foi utilizada uma imagem durante o ciclo da cultura e a produtividade média obtida. A produtividade de fibra variou de 393 a 2.030 kg ha-1 e a correlação com NDVI foi de 0,37. O coeficiente de variação teve correlação negativa, com queda na produtividade em -58,1 kg ha-1 ao aumentar um ponto percentual. O coeficiente de variação explicou melhor a variabilidade da produtividade dos talhões que o NDVI médio.

Reduction of glycemic variability with Degludec insulin in patients with unstable diabetes.

INTRODUCTION: Degludec (IDeg) is an ultralong-acting insulin, with stable pharmacodynamic profile which leads to lower fluctuations in glucose levels. The effect of IDeg has not been specifically assessed in patients with unstable diabetes, defined as increased glycemic variability (GV). METHODS: A prospective before-after pilot study was conducted, including patients managed at Hospital Universitario San Ignacio in Bogotá, Colombia. The impact of the switch from a Glargine or Detemir insulin to a basal insulin regimen with IDeg for 12 weeks on GV measured by continuous glucose monitoring, on A1c levels, and on the incidence of episodes of global and nocturnal hypoglycemia was assessed in a group of patients with (coefficient of variation >34%) or without increased basal GV using a Generalised Estimating Equation (GEE) analysis. RESULTS: 60 patients with basal bolus therapy and history of hypoglycemia were included. 18 patients had High GV (HGV). In this group a significant reduction of 11.1% of CV (95% CI: 6.3, 15.9, p = 0.01) was found. GEE analysis confirmed a higher impact over time on patients with HGV (p < 0.001). The percentage of patients with at least 1 episode of hypoglycemia decreased from 66.6% to 22.2% (p = 0.02) and from 37.14% to 5.71% (p < 0.01) for global and nocturnal hypoglycemia, respectively. Changes were not significant in patients with low GV. A reduction of A1c was observed in both groups (p < 0.001). CONCLUSIONS: The results suggest that treatment with IDeg reduces GV, A1c levels and the incidence of global and nocturnal hypoglycemia events in patients with HGV, but not in patients with low GV.

Optimal quadrat area and sample size to estimate the forage mass of stargrass / Área da moldura e tamanho de amostras para estimar a massa de forragem de capim estrela

The objective of this study was to evaluate the sample size and area of the quadrats necessary to accurately estimate the forage mass (FM) of a fenced pasture of stargrass (Cynodon nlemfuensis cv. Florico) during the winter. Five metal quadrats were used: a 0.09 m² square (0.30 m side), a 0.25 m2 square (0.50 m side), a 0.25 m2 circle (0.28 m diameter), a 0.5 m2 rectangle (0.5 x 1.0 m), and a 1 m2 square (1.0 m side), each with eight replicates. The size and shape of the quadrats were determined based on cumulative variances to identify combinations that minimized the coefficient of variation (CV). The minimum sample size required to estimate the FM, morphological components and height was established by the CV maximum curvature method. The 0.25 m2 square quadrat (0.5 m side) presented the lowest cumulative CV in estimating the FM and the dry mass of dead material. However, for the estimation of the leaf and stem dry mass, the 1.00 m2 square quadrat (1.00 m side) presented the lowest CV. Using the 0.25 m2 square quadrat, a minimum number of six samples were required for the FM estimation, and eight samples were required for estimating the mean height of the stargrass pasture. Therefore, at least eight samples are recommended to obtain accurate results for the estimation of both variables.(AU)

O objetivo desse estudo foi avaliar o tamanho e a área da moldura necessários para estimar a massa de forragem (MF) de um pasto vedado de capim-estrela (Cynodon nlenfluensis cv. Florico) durante o inverno. Foram utilizadas cinco molduras metálicas: quadrado de 0,09 m² (0,30 m de lado), quadrado de 0,25 m² (0,50 m de lado), circular de 0,25 m² (0,28 m de raio), retangular de 0,5 m² (0,5 x 1,0 m) e quadrado de 1 m² (1,0 m de lado), cada uma com oito repetições. A dimensão e o formato da moldura foram determinados com base nas variâncias acumuladas para escolha da combinação com menor coeficiente de variação (CV). O número mínimo de amostras necessárias para estimativa da MF, dos componentes morfológicos e da altura foi estabelecido pelo método da máxima curvatura do CV. A moldura de formato quadrado e 0,25 m2 de área (0,5 m de lado) apresentou menor CV acumulado para estimar a MF e a massa seca de material morto. No entanto, para estimativa da massa seca de folha e de colmo, a moldura de formato quadrado e área de 1,00 m2 (1,00 m de lado) apresentou menor CV. Com o uso da moldura de área 0,25 m2 de formato quadrado, foi estabelecido o número mínimo de seis amostras necessárias para estimativa da MF e oito amostras para estimativa da altura média do pasto de capim-estrela. Portanto, indicam-se no mínimo oito amostras para obter resultados acurados da estimativa de ambas variáveis.(AU)

Improving the reproducibility of motor unit number index.

INTRODUCTION: Reproducibility is an important aspect of any method intended to be a marker of disease progression. In this study we investigated approaches for improving motor unit number index (MUNIX) reproducibility. METHODS: We used the intraclass correlation coefficient (ICC) and the coefficient of variation (CV) to study reproducibility in healthy subjects. We tested reproducibility between test and retest of a single MUNIX from 3 different muscles (S-MUNIX) and also of the mean of a set of 3 measurements from these same muscles (M-MUNIX). RESULTS: M-MUNIX was more reproducible than S-MUNIX. The CV showed a greater improvement than the ICC in all 3 muscles. CONCLUSIONS: M-MUNIX may be a valuable approach for following motor unit loss, because it is more replicable than MUNIX. This may be especially relevant in amyotrophic lateral sclerosis patients, in whom MUNIX variability is higher than in healthy individuals. Muscle Nerve, 2016 Muscle Nerve 55: 635-638, 2017.

Optimal quadrat area and sample size to estimate the forage mass of stargrass / Área da moldura e tamanho de amostras para estimar a massa de forragem de capim estrela

The objective of this study was to evaluate the sample size and area of the quadrats necessary to accurately estimate the forage mass (FM) of a fenced pasture of stargrass (Cynodon nlemfuensis cv. Florico) during the winter. Five metal quadrats were used: a 0.09 m² square (0.30 m side), a 0.25 m2 square (0.50 m side), a 0.25 m2 circle (0.28 m diameter), a 0.5 m2 rectangle (0.5 x 1.0 m), and a 1 m2 square (1.0 m side), each with eight replicates. The size and shape of the quadrats were determined based on cumulative variances to identify combinations that minimized the coefficient of variation (CV). The minimum sample size required to estimate the FM, morphological components and height was established by the CV maximum curvature method. The 0.25 m2 square quadrat (0.5 m side) presented the lowest cumulative CV in estimating the FM and the dry mass of dead material. However, for the estimation of the leaf and stem dry mass, the 1.00 m2 square quadrat (1.00 m side) presented the lowest CV. Using the 0.25 m2 square quadrat, a minimum number of six samples were required for the FM estimation, and eight samples were required for estimating the mean height of the stargrass pasture. Therefore, at least eight samples are recommended to obtain accurate results for the estimation of both variables.

O objetivo desse estudo foi avaliar o tamanho e a área da moldura necessários para estimar a massa de forragem (MF) de um pasto vedado de capim-estrela (Cynodon nlenfluensis cv. Florico) durante o inverno. Foram utilizadas cinco molduras metálicas: quadrado de 0,09 m² (0,30 m de lado), quadrado de 0,25 m² (0,50 m de lado), circular de 0,25 m² (0,28 m de raio), retangular de 0,5 m² (0,5 x 1,0 m) e quadrado de 1 m² (1,0 m de lado), cada uma com oito repetições. A dimensão e o formato da moldura foram determinados com base nas variâncias acumuladas para escolha da combinação com menor coeficiente de variação (CV). O número mínimo de amostras necessárias para estimativa da MF, dos componentes morfológicos e da altura foi estabelecido pelo método da máxima curvatura do CV. A moldura de formato quadrado e 0,25 m2 de área (0,5 m de lado) apresentou menor CV acumulado para estimar a MF e a massa seca de material morto. No entanto, para estimativa da massa seca de folha e de colmo, a moldura de formato quadrado e área de 1,00 m2 (1,00 m de lado) apresentou menor CV. Com o uso da moldura de área 0,25 m2 de formato quadrado, foi estabelecido o número mínimo de seis amostras necessárias para estimativa da MF e oito amostras para estimativa da altura média do pasto de capim-estrela. Portanto, indicam-se no mínimo oito amostras para obter resultados acurados da estimativa de ambas variáveis.

Enhanced liver fibrosis (ELF) score: Analytical performance and distribution range in a large cohort of blood donors.

BACKGROUND: The Enhanced Liver Fibrosis (ELF) is a serological score that includes hyaluronic acid (HA), tissue inhibitor of matrix metalloproteinases-1(TIMP-1), and aminoterminal propeptide of type III procollagen (PIIINP) and shows good performance for detecting liver fibrosis. There are few studies evaluating ELF's intra and inter-assay variation and stability of the samples. The influence of host variables, such as age, gender and body mass index (BMI) is also not well known. We determined ELF's analytical performance and possible influences of gender, age and BMI. METHODS: The study included 958 healthy blood donors evaluated for age, gender, and BMI. RESULTS: Mean ELF scores were significantly different between female (8.53±0.75) and male groups (8.76±0.76) and also according to age strata (p<0.001). For both genders, ELF significantly varied in individuals with BMI under 25 (p<0.001). Analytes remained stable after freezing/thawing cycles and intra- and inter-assay coefficients of variation were low. CONCLUSIONS: ELF has appropriate precision and is quite robust, due to the high stability of the analytes in fresh and frozen samples. ELF's results are influenced by gender, age and BMI which should be taken into account when analyzing its results.

Validation of the Hexoskin wearable vest during lying, sitting, standing, and walking activities.

We tested the validity of the Hexoskin wearable vest to monitor heart rate (HR), breathing rate (BR), tidal volume (VT), minute ventilation, and hip motion intensity (HMI) in comparison with laboratory standard devices during lying, sitting, standing, and walking. Twenty healthy young volunteers participated in this study. First, participants walked 6 min on a treadmill at speeds of 1, 3, and 4.5 km/h followed by increasing treadmill grades until 80% of their predicted maximal heart rate. Second, lying, sitting, and standing tasks were performed (5 min each) followed by 6 min of treadmill walking at 80% of their ventilatory threshold. Analysis of each individual's mean values under each resting or exercise condition by the 2 measurement systems revealed low coefficient of variation and high intraclass correlation values for HR, BR, and HMI. The Bland-Altman results from HR, BR, and HMI indicated no deviation of the mean value from zero and relatively small variability about the mean. VT and minute ventilation were provided in arbitrary units by the Hexoskin device; however, relative magnitude of change from Hexoskin closely tracked the laboratory standard method. Hexoskin presented low variability, good agreement, and consistency. The Hexoskin wearable vest was a valid and consistent tool to monitor activities typical of daily living such as different body positions (lying, sitting, and standing) and various walking speeds.