Alignment transition in a nematic liquid crystal due to field-induced breaking of anchoring

We report on the alignment transition of a nematic liquid crystal from initially homeotropic to quasi-planar due to field-induced anchoring breaking. The initial homeotropic alignment is achieved by Langmuir-Blodgett monolayers. In this geometry the anchoring strength can be evaluated by the Frederiks transition technique. Applying an electric field above a certain threshold provokes turbulent states denoted DSM1 and DSM2. While DSM1 does not affect the anchoring, DSM2 breaks the coupling between the surface and the liquid crystal: switching off the field from a DSM2 state does not immediately restore the homeotropic alignment. Instead, we obtain a quasi-planar metastable alignment. The cell thickness dependence for the transition is related to theComment: 7 pages, LaTeX2e article, 4 figures, 7 EPS files, added references, accepted for publication in Europhysics Letter

Ball Detection and Predictive Ball Following Based on a Stereoscopic Vision System

In this paper we describe an efficient software architecture for object-tracking, based on a stereoscopic vision system, that has been applied to a mobile robot controlled by a PC. After analyzing the epipolar rectification required to correct the original stereo-images, it is described a new valid and efficient algorithm for ball recognition (indeed circle detection) which is able to work in different lighting conditions and in a manner faster than some modified versions of Circle Hough Transform. Then, we show that stereo vision, besides giving an optimum estimation of the 3D position of the object, is useful to remove lots of the false identifications of the ball, thanks to the advantages of epipolar constraint. Finally, we describe a new strategy for ball following, by a mobile robot, which is able to look for the object whenever it comes out of the cameras view, by taking advantage of a block matching method similar to that of MPEG Video

Characterizing LEDAPS surface reflectance products by comparisons with AERONET, field spectrometer, and MODIS data

This study provides a baseline quality check on provisional Landsat Surface Reflectance (SR) products as generated by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center using Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software. Characterization of the Landsat SR products leveraged comparisons between aerosol optical thickness derived from LEDAPS and measured by Aerosol Robotic Network (AERONET), as well as reflectance correlations with field spectrometer and Moderate Resolution Imaging Spectroradiometer (MODIS) data. Results consistently indicated similarity between LEDAPS and alternative data products in longer wavelengths over vegetated areas with no adjacent water, while less reliable performance was observed in shorter wavelengths and sparsely vegetated areas. This study demonstrates the strengths and weaknesses of the atmospheric correction methodology used in LEDAPS, confirming its successful implementation to generate Landsat SR products

Characterizing LEDAPS surface reflectance products by comparisons with AERONET, field spectrometer, and MODIS data

This study provides a baseline quality check on provisional Landsat Surface Reflectance (SR) products as generated by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center using Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software. Characterization of the Landsat SR products leveraged comparisons between aerosol optical thickness derived from LEDAPS and measured by Aerosol Robotic Network (AERONET), as well as reflectance correlations with field spectrometer and Moderate Resolution Imaging Spectroradiometer (MODIS) data. Results consistently indicated similarity between LEDAPS and alternative data products in longer wavelengths over vegetated areas with no adjacent water, while less reliable performance was observed in shorter wavelengths and sparsely vegetated areas. This study demonstrates the strengths and weaknesses of the atmospheric correction methodology used in LEDAPS, confirming its successful implementation to generate Landsat SR products

Sensitive methods for estimating the anchoring strength of nematic liquid crystals on Langmuir-Blodgett monolayers of fatty acids

The anchoring of the nematic liquid crystal N-(p-methoxybenzylidene)-p-butylaniline (MBBA) on Langmuir-Blodgett monolayers of fatty acids (COOHC$_{n}$H$_{2n+1}$) was studied as a function of the length of the fatty acid alkyl chains, $n$ ($n = 15, 17, 19, 21$). The monolayers were deposited onto ITO-coated glass plates which were used to assemble sandwich cells of various thickness that were filled with MBBA in the nematic phase. The mechanism of relaxation from the flow-induced quasi-planar to the surface-induced homeotropic alignment was studied for the four decreases linearly with increasing the length of the alkyl chains $n$ which suggests that the Langmuir-Blodgett film plays a role in the phenomenon. This fact was confirmed by a sensitive estimation of the anchoring strength of MBBA on the fatty acid monolayers after anchoring breaking which takes place at the transition between two electric-field--induced turbulent states, denoted as DSM1 and DSM2. It was found that the threshold electric field for the anchoring breaking, which can be considered as a measure of the anchoring strength, also decreases linearly as $n$ increases. Both methods thus possess a high sensitivity in resolving small differences in anchoring strength. In cells coated with mixed Langmuir-Blodgett monolayers of two fatty acids ($n=15$ and $n=17$) a maximum of the relaxation speed was observed when the two acids were present in equal amount. This observation homeotropic cells by changing the ratio between the components of the surfactant film.Comment: LaTeX article, 20 pages, 15 figures, 17 EPS files. 1 figure added, references moved. Submitted to Phys. Rev.

Diet management, lifestyle factors and education needs by target attainment in Italian youth with type 1 diabetes from the Global TEENs study

Background and aims: TEENs is an international, cross-sectional observational study, conducted in 20 countries in order to assess T1D management and psychosocial parameters in 8-25-year-olds (y/o). Data on diet management, lifestyle factors and education needs by target HbA1c attainment from the Italian cohort are reported. Materials and methods: Data were collected at 23 centres by participant interview, medical record review and participant/parent survey from 1,009 Italian youth (46% female) in three age groups: 8-12 y/o (n=330), 13-18 y/o (n=490), and 19-25 y/o (n=189). HbA1c was measured uniformly using A1cNow™ with target HbA1c defined as <7.5% (58 mmol/mol) for ≤18 y/o (ISPAD) and <7% (53 mmol/mol) for >18 y/o (ADA). Results: Overall, 40% of participants met HbA1c targets. Measuring food intake based on experience was the most common method used by all age groups, followed by carbohydrate counting (Table). Of the participants who used carbohydrate counting, a higher percentage met target HbA1c than did not in all age groups, with a significant effect on target attainment due to carbohydrate counting compared with other methods observed in 13-18 y/o (p=0.035). Avoiding sugars was the least common method used in all age groups. Across all age groups, participants who did not undertake any exercise were numerically less likely to reach HbA1c target; on the contrary, participants who exercised 1-2 days/week were numerically more likely to reach HbA1c target. Performing exercise had a significant effect on target HbA1c attainment in 8-12 y/o (p=0.012). The majority of participants were in the underweight/normal body mass index (BMI) category in all age groups, with no clear pattern between BMI class and the proportion of patients reaching HbA1c target. Participants of all ages commonly requested education on diet, carbohydrate counting, how to manage T1D during illness, and how to manage blood glucose levels with exercise. Conclusion: Carbohydrate counting and exercising at least twice per week help to attain HbA1c target across all age groups. Assessment of lifestyle factors suggests that efforts targeting carbohydrate counting and exercise could promote successful health outcomes and help more patients with T1D to reach the recommended HbA1c target. Supported by: Sanof

Vision-Depth Landmarks and Inertial Fusion for Navigation in Degraded Visual Environments

This paper proposes a method for tight fusion of visual, depth and inertial data in order to extend robotic capabilities for navigation in GPS-denied, poorly illuminated, and texture-less environments. Visual and depth information are fused at the feature detection and descriptor extraction levels to augment one sensing modality with the other. These multimodal features are then further integrated with inertial sensor cues using an extended Kalman filter to estimate the robot pose, sensor bias terms, and landmark positions simultaneously as part of the filter state. As demonstrated through a set of hand-held and Micro Aerial Vehicle experiments, the proposed algorithm is shown to perform reliably in challenging visually-degraded environments using RGB-D information from a lightweight and low-cost sensor and data from an IMU.Comment: 11 pages, 6 figures, Published in International Symposium on Visual Computing (ISVC) 201

Combined Therapy with Insulin and Growth Hormone in 17 Patients with Type-1 Diabetes and Growth Disorders.

Combined growth hormone (GH) and insulin therapy is rarely prescribed by pediatric endocrinologists. We investigated the attitude of Italian physicians to prescribing that therapy in the case of short stature and type-1 diabetes (T1DM). Methods: A questionnaire was sent and if a patient was identified, data on growth and diabetes management were collected. Results: Data from 42 centers (84%) were obtained. Of these, 29 centers reported that the use of combined therapy was usually avoided. A total of 17 patients were treated in 13 centers (GH was started before T1DM onset in 9 patients and after the onset of T1DM in 8). Height SDS patterns during GH therapy in the 11 patients affected by GH deficiency ranged from -0.3 to +3.1 SDS. In the 8 diabetic patients in whom GH was added subsequently, mean insulin dose increased during the first 6 months of therapy from 0.7 ± 0.2 to 1.0 ± 0.2 U/kg (p = 0.004). HbA1c was unchanged during the first 6 months of combined therapy. Conclusions: Most Italian physicians do not consider prescribing the combined GH-insulin therapy in diabetic children with growth problems. However, the results of the 17 patients identified would confirm that the combined therapy was feasible and only caused mild insulin resistance. GH therapy was effective in promoting growth in most patients and did not affect diabetes metabolic contro

How digital is agriculture in a subset of countries from South America? Adoption and limitations

Digital agriculture (DA) can contribute solutions to meet an increase in healthy, nutritious, and affordable food demands in an efficient and sustainable way. South America (SA) is one of the main grain and protein producers in the world but the status of DA in the region is unknown. A systematic review and case studies from Brazil, Argentina, Uruguay, and Chile were conducted to address the following objectives: (1) quantify adoption of existing DA technologies, (2) identify limitations for DA adoption; and (3) summarise existing metrics to benchmark DA benefits. Level of DA adoption was led by Brazil and Argentina followed by Uruguay and at a slower rate, Chile. GPS guidance systems, mapping tools, mobile apps and remote sensing were the most adopted DA technologies in SA. The most reported limitations to adoption were technology cost, lack of training, limited number of companies providing services, and unclear benefits from DA. Across the case studies, there was no clear definition of DA. To mitigate some of these limitations, our findings suggest the need for a DA educational curriculum that can fulfill the demand for job skills such as data processing, analysis and interpretation. Regional efforts are needed to standardise these metrics. This will allow stakeholders to design targeted initiatives to promote DA towards sustainability of food production in the region