843 research outputs found

    A contour matching approach for accurate NOAA-AVHRR image navigation

    Get PDF
    Although different methods for NOAA AVHRR image navigation have already been established, the multitemporal and multi-satellite character of most studies requires automatic and accurate methods for navigation of satellite images. In the proposed method, a simple Kepplerian orbital model for the NOAA satellites is considered as reference model, and mean orbital elements are given as input to the model from ephemeris data. In order to correct the errors caused by these simplifications, errors resulting from inaccuracies in the positioning of the satellite and failures in the satellite internal clock, an automatic global contour matching approach has been adopted. First, the sensed image is preprocessed to obtain a gradient energy map of the reliable areas (sea-land contours) using a cloud detection algorithm and a morphological gradient operator. An initial estimation of the reliable contour positions is automatically obtained. The final positions of the contours are obtained by means of an iterative local minimization procedure that allows a contour to converge on an area of high image energy (edge). Global transformation parameters are estimated based on the initial and final positions of all reliable contour points. Finally, the performance of this approach is assessed using NOAA 14 AVHRR images from different geographic areas.Postprint (published version

    Accurate and automatic NOAA-AVHRR image navigation using a global contour matching approach

    Get PDF
    The problem of precise and automatic AVHRR image navigation is tractable in theory, but has proved to be somewhat difficult in practice. The authors' work has been motivated by the need for a fully automatic and operational navigation system capable of geo-referencing NOAA-AVHRR images with high accuracy and without operator supervision. The proposed method is based on the simultaneous use of an orbital model and a contour matching approach. This last process, relying on an affine transformation model, is used to correct the errors caused by inaccuracies in orbit modeling, nonzero value for the spacecraft's roll, pitch and yaw, errors due to inaccuracies in the satellite positioning and failures in the satellite internal clock. The automatic global contour matching process is summarized as follows: i) Estimation of the gradient energy map (edges) in the sensed image and detection of the cloudless (reliable) areas in this map. ii) Initialization of the affine model parameters by minimizing the Euclidean distance between the reference and sensed images objects. iii) Simultaneous optimization of all reference image contours on the sensed image by energy minimization in the domain of the global transformation parameters. The process is iterated in a hierarchical way, reducing the parameter searching space at each iteration. The proposed image navigation algorithm has proved to be capable of geo-referencing a satellite image within 1 pixel.Peer ReviewedPostprint (published version

    Services and the Business Models of Product Firms: An Empirical Analysis of the Software Industry

    Get PDF
    Some product firms increasingly rely on service revenues as part of their business models. One possible explanation is that they turn to services to generate additional profits when their product industries mature and product revenues and profits decline. We explore this assumption by examining the role of services in the financial performance of firms in the prepackaged software products industry (Standard Industrial Classification code 7372) from 1990 to 2006. We find a convex, nonlinear relationship between a product firm's fraction of total sales coming from services and its overall operating margins. As expected, firms with a very high level of product sales are most profitable, and rising services are associated with declining profitability. We find, however, that additional services start to have a positive marginal effect on the firm's overall profits when services reach a majority of a product firm's sales. We show that traditional industry maturity arguments cannot fully explain our data. It is likely that changes in both strategy and the business environment lead product firms to place more emphasis on services

    The hybrid trap: Why most efforts to bridge old and new technology miss the mark

    Get PDF
    Technological transitions are challenging, particularly for companies in mature industries. Incumbents are frequently blindsided by new technologies, fully missing opportunities to enter emerging markets early. While some established companies do possess the awareness and dexterity to become early adopters of new technologies, they typically lack the vision and the commitment to become leaders. Too often, they cling to the familiar, developing hybrid products that combine elements of the old and the new. The trouble is, hybrid strategies put even the best incumbent companies in a weak position when the market finally embraces the new technology. We call this the "hybrid trap." The transition from internal combustion engines to electric vehicles demonstrates the dangers of hesitating to embrace the new. New markets are often enabled by technological change and exploited by minds that can envision futures that are far different from the status quo. More so, they are convinced that such a future must happen.1

    Brote de mastitis clínica por Corynebacterium spp. y Streptococcus dysgalactiae en cabras en Salta, Argentina

    Get PDF
    Las infecciones mamarias son un problema grave para la producción lechera en cabras a nivel mundial. Staphylococcus spp. es el patógeno más prevalente en las infecciones intramamarias de los pequeños rumiantes, sin embargo, es escasa la información acerca de mastitis caprinas en LA Argentina. El objetivo de esta comunicación es describir un brote de mastitis clínica que afectó a 12 de 24 cabras lecheras. Corynebacterium spp. y Streptococus dysgalactiae fueron aislados en forma pura de las muestras de leche. Todos los aislamientos fueron identificados bioquímicamente y sometidos a prueba de sensibilidad antibiótica.Intramammary infections are a serious problem for goat’s milk production worldwide. Staphylococcus spp. are the most prevalent pathogens responsible for intramammary infection in small ruminants; however, there is only little information about goat mastitis in Argentina. The objective of this communication was to describe an outbreak of clinical mastitis affecting 12 of 24 lactating goats. Corynebacterium spp. and Streptococcus dysgalactiae were isolated in pure culture from all milk samples. All the clinical isolates were identified by biochemical tests and subjected to antibiotic susceptibility tests.EEA SaltaFil: Micheloud, Juan Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Neder, Veronica Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Nuovo, F. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Suarez, Victor Humberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Calvinho, Luis Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

    RoboCrane: a system for providing a power and a communication link between lunar surface and lunar caves for exploring robots

    Get PDF
    Lava caves are the result of a geological process related to the cooling of basaltic lava flows. On the Moon, this process may lead to caves several kilometers long and diameters of hundreds of meters. Access to lava tubes can be granted through skylights, a vertical pit between the lava tube and the lunar surface. This represents an outstanding opportunity for long-term missions, for future permanent human settlements, and for accessing pristine samples of lava, secondary minerals and volatiles. Given this, the ESA launched a campaign through the Open Space Innovation Platform calling for ideas that would tackle the many challenges of exploring lava pits. Five projects, including Robocrane, were selected. Solar light and direct line of sight (for communications) with the lunar surface are not available inside lava tubes. This is a problem for any robot (or swarm of robots) exploring the lava tubes. Robocrane tackles both problems by deploying an element (called the Charging head, or CH) at the bottom of the skylight by means of a crane. This CH behaves as a battery charger and a communication relay for the exploring robots. The required energy is extracted from the crane’s solar panel (on the surface) and driven to the bottom of the skylight through an electrical wire running in parallel to the crane hoisting wire. Using a crane allows the system to deal with unstable terrain around the skylight rim and protect the wires from abrasion from the rocky surface and the pit rim. The charger in the CH is wireless so that the charging process can begin as soon as any of the robots get close enough to the CH. This avoids complex and time-consuming docking operations, aggravated by the skylight floor orography. The crane infrastructure can also be used to deploy the exploring robots inside the pit, reducing their design constraints and mass budget, as the robots do not need to implement their own self-deployment system. Finally, RoboCrane includes all the sensors and actuators for remote operation from a ground station. RoboCrane has been designed in a parametric tool so it can be dynamically and rapidly adjusted to input-variable changes, such as the number of exploring robots, their electrical characteristics, and crane reach, etc.Agencia Estatal de Investigación | Ref. RTI2018-099682-A-I0

    Prognostic and predictive factors in recurrent and/or metastatic head and neck squamous cell carcinoma : A review of the literature

    Get PDF
    The pattern of clinical behaviour and response to treatment of recurrent and/or metastatic head and neck squamous cell carcinoma is heterogeneous. Treatment strategies that can be employed vary from potentially curative salvage surgery and re-irradiation to palliative systemic therapies and best supportive care. The advent of new therapeutic options, in terms of more sophisticated surgical approaches and techniques, highly conformal and precise radiation techniques and immunotherapy may offer improved control of disease and longer survival. Moreover, the epidemiological changes during the last decades, including the increase of human papilloma virus-related oropharyngeal primary tumors, are also reflected in the recurrent and metastatic setting. In this complex context the identification of predictive and prognostic factors is urgently needed to tailor treatment, to increase its efficacy, and to avoid unnecessary toxicities. A better knowledge of prognosis may also help the patients and caregivers in decision making on the optimal choice of care. The purpose of our review is to highlight the current evidence and shortcomings in this field.Peer reviewe

    Genetic mapping for agronomic traits in a MAGIC population of common bean (Phaseolus vulgaris L.) under drought conditions

    Get PDF
    Background Common bean is an important staple crop in the tropics of Africa, Asia and the Americas. Particularly smallholder farmers rely on bean as a source for calories, protein and micronutrients. Drought is a major production constraint for common bean, a situation that will be aggravated with current climate change scenarios. In this context, new tools designed to understand the genetic basis governing the phenotypic responses to abiotic stress are required to improve transfer of desirable traits into cultivated beans. Results A multiparent advanced generation intercross (MAGIC) population of common bean was generated from eight Mesoamerican breeding lines representing the phenotypic and genotypic diversity of the CIAT Mesoamerican breeding program. This population was assessed under drought conditions in two field trials for yield, 100 seed weight, iron and zinc accumulation, phenology and pod harvest index. Transgressive segregation was observed for most of these traits. Yield was positively correlated with yield components and pod harvest index (PHI), and negative correlations were found with phenology traits and micromineral contents. Founder haplotypes in the population were identified using Genotyping by Sequencing (GBS). No major population structure was observed in the population. Whole Genome Sequencing (WGS) data from the founder lines was used to impute genotyping data for GWAS. Genetic mapping was carried out with two methods, using association mapping with GWAS, and linkage mapping with haplotype-based interval screening. Thirteen high confidence QTL were identified using both methods and several QTL hotspots were found controlling multiple traits. A major QTL hotspot located on chromosome Pv01 for phenology traits and yield was identified. Further hotspots affecting several traits were observed on chromosomes Pv03 and Pv08. A major QTL for seed Fe content was contributed by MIB778, the founder line with highest micromineral accumulation. Based on imputed WGS data, candidate genes are reported for the identified major QTL, and sequence changes were identified that could cause the phenotypic variation. Conclusions This work demonstrates the importance of this common bean MAGIC population for genetic mapping of agronomic traits, to identify trait associations for molecular breeding tool design and as a new genetic resource for the bean research community

    Evaluation of different bowel preparations for small bowel capsule endoscopy: a prospective, randomized, controlled study

    Get PDF
    To obtain an adequate view of the whole small intestine during capsule endoscopy (CE) a clear liquid diet and overnight fasting is recommended. However, intestinal content can hamper vision in spite of these measures. Our aim was to evaluate tolerance and degree of intestinal cleanliness during CE following three types of bowel preparation. PATIENTS AND METHODS: This was a prospective, multicenter, randomized, controlled study. Two-hundred ninety-one patients underwent one of the following preparations: 4 L of clear liquids (CL) (group A; 92 patients); 90 mL of aqueous sodium phosphate (group B; 89 patients); or 4 L of a polyethylene glycol electrolyte solution (group C; 92 patients). The degree of cleanliness of the small bowel was classified by blinded examiners according to four categories (excellent, good, fair or poor). The degree of patient satisfaction, gastric and small bowel transit times, and diagnostic yield were measured. RESULTS: The degree of cleanliness did not differ significantly between the groups (P = 0.496). Interobserver concordance was fair (k = 0.38). No significant differences were detected between the diagnostic yields of the CE (P = 0.601). Gastric transit time was 35.7 +/- 3.7 min (group A), 46.1 +/- 8.6 min (group B) and 34.6 +/- 5.0 min (group C) (P = 0.417). Small-intestinal transit time was 276.9 +/- 10.7 min (group A), 249.7 +/- 13.1 min (group B) and 245.6 +/- 11.6 min (group C) (P = 0.120). CL was the best tolerated preparation. Compliance with the bowel preparation regimen was lowest in group C (P = 0.008). CONCLUSIONS: A clear liquid diet and overnight fasting is sufficient to achieve an adequate level of cleanliness and is better tolerated by patients than other forms of preparation
    • …
    corecore