36 research outputs found

    Dense, low-power environmental monitoring for smart energy profiling

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    Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 49).Recent architectural trends have included exploring open space and the extensive use of glass as building material. While the details of these large, light-exposed, open-air environments can be modeled as thermal fluid systems in CFD simulations, the use of dense sensor networks can provide real-time monitoring of a building's airflow and thermal management systems without the need for computationally-intensive theoretical models, and can use this data to inform and advance these models. Sensor networks can provide an accurate picture of the actual conditions of a building and how those conditions can change over time, due to deterioration or external influences. The information gathered from such networks will be critical in determining the energy efficiency of a building. To do this, a sensor network made of two types of sensors, temperature-humidity and airflow, was deployed in the large, glass-enclosed atrium of the recently-completed MIT Media Lab Extension (E14) in late March 2010. Their performance was calibrated, monitored, and the preliminary results analyzed in conjunction with the external weather conditions in the Boston metropolitan area. The results show that while the use of the sensors in monitoring temperature and humidity is successful, the airflow sensors currently require a different solution to solve both the need for low-power consumption and resolution, range, and stability in its measurements.by Ashley K. Turza.S.B

    Allogeneic Whole Pancreas Transplantation in Insulin-Dependent Diabetes Mellitus

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    A clinical whole organ pancreas transplantation program for patients with insulin-dependent diabetes mellitus complicated by end-stage renal disease was initiated at Henry Ford Hospital in 1987. Five patients have received pancreatic allografts after a previous kidney transplant (phase 1), and six patients had simultaneous pancreas-kidney transplants (phase 2). Ten patients had functioning pancreatic grafts after surgery, and all of them had normal carbohydrate tolerance with appropriate plasma free insulin responses to an oral glucose tolerance test three months after transplantation. As long as 28 months postsurgery six patients remained free of insulin requirements; however, one patient rejected the pancreatic allograft, and three patients died because of cytomegalovirus pneumonia. Two of the latter patients had functioning pancreatic allografts at the time of their demise. These results compare favorably with those of the International Pancreas Transplant Registry which reflects the world experience. Pancreas transplantation is a unique experimental treatment with the potential of restoring euglycemia and improving the prognosis of insulin-dependent diabetic patients

    Fibre-optic delivery of time and frequency to VLBI station

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    The quality of Very Long Baseline Interferometry (VLBI) radio observations predominantly relies on precise and ultra-stable time and frequency (T&F) standards, usually hydrogen masers (HM), maintained locally at each VLBI station. Here, we present an operational solution in which the VLBI observations are routinely carried out without use of a local HM, but using remote synchronization via a stabilized, long-distance fibre-optic link. The T&F reference signals, traceable to international atomic timescale (TAI), are delivered to the VLBI station from a dedicated timekeeping laboratory. Moreover, we describe a proof-of-concept experiment where the VLBI station is synchronized to a remote strontium optical lattice clock during the observation.Comment: 8 pages, 8 figures, matches the version published in A&A, section Astronomical instrumentatio

    Dense, low-power sensor network for three-dimensional thermal characterization of large-scale atria spaces

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    We describe the design and implementation of a dense, low-power wireless sensor network for fine-grained three-dimensional thermal characterization of a large open indoor space. To better understand the airflow dynamics and ensuing energy efficiency potential of this type of modern architectural design, we developed a sustainable wireless mesh network consisting of 50 sensors hung on an array of thin cables in a 210 m[superscript 2], 14.2 m tall atrium for real-time temperature and humidity monitoring. The goal is to create compact wireless measurement sensor blocks for dense coverage in the building. We demonstrate the implementation through a preliminary analysis, which includes the evaluation of temperature distribution discrepancies with computer-simulated results and data taken during natural ventilation to illustrate the nontrivial, well-mixed temperatures observed during the studies.Massachusetts Institute of Technology. Media LaboratorySchneider Electric (Firm

    The effect of adenosine monophosphate deaminase overexpression on the accumulation of umami-related metabolites in tomatoes

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    Taste is perceived as one of a combination of five sensations, sweet, sour, bitter, salty, and umami. The umami taste is best known as a savoury sensation and plays a central role in food flavour, palatability, and eating satisfaction. Umami flavour can be imparted by the presence of glutamate and is greatly enhanced by the addition of ribonucleotides, such as inosine monophosphate (IMP) and guanosine monophosphate (GMP). The production of IMP is regulated by the enzyme adenosine monophosphate (AMP) deaminase which functions to convert AMP into IMP. We have generated transgenic tomato (Solanum lycopersicum) lines over expressing AMP deaminase under the control of a fruit-specific promoter. The transgenic lines showed substantially enhanced levels of AMP deaminase expression in comparison to the wild-type control. Elevated AMP deaminase levels resulted in the reduced accumulation of glutamate and increased levels of the umami nucleotide GMP. AMP concentrations were unchanged. The effects on the levels of glutamate and GMP were unexpected and are discussed in relation to the metabolite flux within this pathway

    Long-term postharvest aroma evolution of tomatoes with the alcobaça (alc) mutation

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    The postharvest evolution of Penjar tomatoes has been studied in four accessions representative of the variability of the varietal type. The long-term shelf life of these materials, which carry the alc allele, was confirmed with 31.2-59.1% of commercial fruits after 6 months of effective conservation at room temperature and a limited loss of weight (21.1-27.9%). Aroma in Penjar tomatoes is differentiated from other tomato varieties by a characteristic 'sharp-floral' aroma descriptor. The evolution of the 'sharp-floral' aroma during postharvest showed a peak of intensity at 2 months of postharvest, though in one accession a delay of 2 months in this response was detected. Out of 25 volatiles analysed, including main and background notes, a reverse iPLS variable selection revealed that the main candidates behind this aromatic behaviour are ¿-terpineol, trans-2-hexenal, 6-methyl-5-hepten-2-one, trans-2-octenal, ¿-pinene, ß-ionone, 2 + 3-methylbutanol and phenylacetaldehyde. Between harvest and 2 months postharvest, most compounds reduced considerably their concentration, while the intensity of the 'sharp-floral' descriptor increased, which means that probably there is a rearrangement of the relative concentrations among volatiles that may lead to masking/unmasking processes. © 2011 Springer-Verlag.This work was supported by grants from the Conselleria de Agricultura, Pesca y Alimentacio de la Comunidad Valenciana, the Fundacion de la Comunidad Valenciana para la Investigacion Agroalimentaria (AGROALIMED) and from the Departament d'Agricultura, Alimentacio i Accio Rural (DAR) de la Generalitat de Catalunya.Casals Missio, J.; Cebolla Cornejo, J.; Rosello Ripolles, S.; Beltran Arandes, J.; Casanas, F.; Nuez Viñals, F. (2011). Long-term postharvest aroma evolution of tomatoes with the alcobaça (alc) mutation. 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    ATR-FTIR spectroscopy non-destructively detects damage-induced sour rot infection in whole tomato fruit

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    Main conclusion ATR-FTIR spectroscopy with subsequent multivariate analysis non-destructively identifies plant–pathogen interactions during disease progression, both directly and indirectly, through alterations in the spectral fingerprint. Plant–environment interactions are essential to understanding crop biology, optimizing crop use, and minimizing loss to ensure food security. Damage-induced pathogen infection of delicate fruit crops such as tomato (Solanum lycopersicum) are therefore important processes related to crop biology and modern horticulture. Fruit epidermis as a first barrier at the plant–environment interface, is specifically involved in environmental interactions and often shows substantial structural and functional changes in response to unfavourable conditions. Methods available to investigate such systems in their native form, however, are limited by often required and destructive sample preparation, or scarce amounts of molecular level information. To explore biochemical changes and evaluate diagnostic potential for damage-induced pathogen infection of cherry tomato (cv. Piccolo) both directly and indirectly, mid-infrared (MIR) spectroscopy was applied in combination with exploratory multivariate analysis. ATR-FTIR fingerprint spectra (1800–900 cm−1) of healthy, damaged or sour rot-infected tomato fruit were acquired and distinguished using principal component analysis and linear discriminant analysis (PCA–LDA). Main biochemical constituents of healthy tomato fruit epidermis are characterized while multivariate analysis discriminated subtle biochemical changes distinguishing healthy tomato from damaged, early or late sour rot-infected tomato indirectly based solely on changes in the fruit epidermis. Sour rot causing agent Geotrichum candidum was detected directly in vivo and characterized based on spectral features distinct from tomato fruit. Diagnostic potential for indirect pathogen detection based on tomato fruit skin was evaluated using the linear discriminant classifier (PCA–LDC). Exploratory and diagnostic analysis of ATR-FTIR spectra offers biological insights and detection potential for intact plant–pathogen systems as they are found in horticultural industries
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