1,082 research outputs found

    Fast wavelength switching lasers using two-section slotted Fabry-Pérot structures

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    Fast wavelength switching of a two-section slotted Fabry–PÉrot laser structure is presented. The slot design enables operation at five discrete wavelength channels spaced by 10 nm by tuning one section of the device. These wavelengths operate with sidemode suppression ratio in excess of 35 dB, and switching times between these channels of approximately 1 ns are demonstrated

    Effects of Seasonal Variation in Milk Composition on the Quality of Pizza Cheese

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    End of Project ReportThe main aims of this study were to investigate the effects of diet and lactation stage on the composition and cheesemaking quality of milk produced under controlled conditions. The main conclusions were as follows: These studies clearly demonstrated that the Recommended Moorepark Milk Production System in conjunction with an objectively standardised cheesemaking process provides a model for year round production of quality Mozzarella cheese. Databases have been established on the effects of diet quantity and quality, and stage of lactation on the composition, processability and cheesemaking characteristics of milk from both Spring- and Autumn-calving herds. Increasing the daily herbage allowance from 16 to 24 kgs DM/cow/day during mid-lactation, resulted in increases in the level of milk casein and cheese yield but had little influence on cheese functionality. Similarily improving diet quality in mid-lactation by reducing the stocking density from 4.3 to 3.8 cows/ha combined with concentrate supplementation (3 kgs/cow/day) had the same effect. Using milk from a Spring-calving herd, produced according to the Recommended Moorepark Milk Production System, in conjunction with an objectively-standardised Mozzarella cheesemaking process, no major problems were encountered during the lactation period 170 - 273 days from calving. Extending the lactation period of the Spring-calving herd from ~ 273 to 286 days resulted in higher cheese moisture (by ~ 2%), softer cheese, and lower chewiness in the melted cheese. A sharp decline in both total protein, casein and lactose in the milk was observed during this period. However the blending of this milk with milk of an Autumn-calving herd overcame these cheesemaking problems. The yield of low moisture Mozzarella cheese (using milks from Spring- or Autumn-calved herds) was positively correlated with milk casein level. The yield of cheese from the Spring-calved herd increased concomitantly with increasing casein level to day 273 of lactation and decreased thereafter as the casein concentration declined. In these studies it was found that easy-to-use tests such as lactose level in the milk and rennet coagulation properties as determined by Formagraph were useful indicators of the suitability of milk for cheesemaking. The Recommended Moorepark Milk Production System, as applied in the late lactation period, was characterised by a high plane of nutrition and a drying-off strategy which ensured a minimum daily milk yield per cow of 9 kg. It resulted in milk of good cheesemaking quality - lactose > 4.25%, and casein > 2.6% and satisfactory rennet coagulation properties - curd firming rate of > 0.15 min ¯¹ curd firmness at 60 min of > 45mm - at the end of lactation.Department of Agriculture, Food and the Marin

    NASA Space applications of high-temperature superconductors

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    The application of superconducting technology in space has been limited by the requirement of cooling to near liquid helium temperatures. The only means of obtaining these temperatures has been with cryogenic fluids which severely limit mission lifetime. The development of materials with superconducting transition temperatures above 77 K has made superconducting technology more attractive and feasible for employment in aerospace systems. Here, potential applications of high temperature superconducting technology in cryocoolers, remote sensing, communications, and power systems are discussed

    Pixel-z: Studying Substructure and Stellar Populations in Galaxies out to z~3 using Pixel Colors I. Systematics

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    We perform a pixel-by-pixel analysis of 467 galaxies in the GOODS-VIMOS survey to study systematic effects in extracting properties of stellar populations (age, dust, metallicity and SFR) from pixel colors using the pixel-z method. The systematics studied include the effect of the input stellar population synthesis model, passband limitations and differences between individual SED fits to pixels and global SED-fitting to a galaxy's colors. We find that with optical-only colors, the systematic errors due to differences among the models are well constrained. The largest impact on the age and SFR e-folding time estimates in the pixels arises from differences between the Maraston models and the Bruzual&Charlot models, when optical colors are used. This results in systematic differences larger than the 2{\sigma} uncertainties in over 10 percent of all pixels in the galaxy sample. The effect of restricting the available passbands is more severe. In 26 percent of pixels in the full sample, passband limitations result in systematic biases in the age estimates which are larger than the 2{\sigma} uncertainties. Systematic effects from model differences are reexamined using Near-IR colors for a subsample of 46 galaxies in the GOODS-NICMOS survey. For z > 1, the observed optical/NIR colors span the rest frame UV-optical SED, and the use of different models does not significantly bias the estimates of the stellar population parameters compared to using optical-only colors. We then illustrate how pixel-z can be applied robustly to make detailed studies of substructure in high redshift galaxies such as (a) radial gradients of age, SFR, sSFR and dust and (b) the distribution of these properties within subcomponents such as spiral arms and clumps. Finally, we show preliminary results from the CANDELS survey illustrating how the new HST/WFC3 data can be exploited to probe substructure in z~1-3 galaxies.Comment: 37 pages, 21 figures, submitted to Ap

    Assessing the Preferences for Criteria in Multi-Criteria Decision Analysis in Treatments for Rare Diseases

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    Background: Increasingly, multi-criteria decision analysis has gained importance as a method by which to assess the value of orphan drugs. However, very little attention has been given to the weight (relative preferences) of the individual criteria used in a framework. Aims: This study sought to gain an understanding of the preferential weights that should be allocated in a multi-criteria decision analysis framework for orphan drugs, from a multi-stakeholder perspective. Method: Using key MCDA criteria for orphan drugs reported in the literature, we developed an interactive web-based survey tool to capture preferences for different criteria from a general stakeholder sample who were requested to assign weights from a reimbursement perspective. Each criterion could be assigned a weight on a sliding scale from 0 to 100% as long as the sum of all the criteria was 100%. We subsequently used the interactive tool with an expert focus group, followed up with a group discussion regarding each criterion and their perspectives on the weight that each criterion should be allocated when assessing an orphan drug. The expert focus group participants were then able to adjust their weights, if the group discussion had changed their perspectives. Results: The interactive tool was completed by 120 general stakeholder sample from a wide range of countries and professional backgrounds and an expert focus group of ten members. The results showed the differences in perspectives on the importance of criteria. Both groups considered Treatment efficacy to be the most important criterion. The general stakeholder sample weighted Treatment safety at 12.03% compared to the expert focus group's average of 20%. The results also demonstrated the value of the group discussion, which provided additional insights into the perspectives on the importance of criteria in assessing orphan drugs. Conclusion: This study aimed to contribute to the important aspect of preferences for different criteria in MCDA. This study sheds light on the important aspect of the preferences of the different criteria. All respondents agreed on the relative importance of Treatment efficacy and Treatment safety, criteria that are captured in conventional cost-effectiveness studies, but they also expressed the view that in addition to those, several disease-related and drug-related criteria should be included in MCDA frameworks for assessing orphan drugs

    miR-542 promotes mitochondrial dysfunction and SMAD activity and is raised in ICU Acquired Weakness

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    Rationale: Loss of skeletal muscle mass and function is a common consequence of critical illness and a range of chronic diseases but the mechanisms by which this occurs are unclear. Objectives: We aimed to identify miRNAs that were increased in the quadriceps of patients with muscle wasting and to determine the molecular pathways by which they contributed to muscle dysfunction. Methods: miR-542-3p/-5p were quantified in the quadriceps of patients with COPD and intensive care unit acquired weakness (ICUAW). The effect of miR-542-3p/5p was determined on mitochondrial function and TGF-β signaling in vitro and in vivo. Measurements and main results: miR-542-3p/5p were elevated in patients with COPD but more markedly in patients with ICUAW. In vitro, miR-542-3p suppressed the expression of the mitochondrial ribosomal protein MRPS10, and reduced 12S rRNA expression suggesting mitochondrial ribosomal stress. miR-542-5p increased nuclear phospho-SMAD2/3 and suppressed expression of SMAD7, SMURF1 and PPP2CA, proteins that inhibit or reduce SMAD2/3 phosphorylation suggesting that miR-542-5p increased TGF-β signaling. In mice, miR-542 over-expression caused muscle wasting, reduced mitochondrial function, 12S rRNA expression and SMAD7 expression, consistent with the effects of the miRNAs in vitro. Similarly, in patients with ICUAW, the expression of 12S rRNA and of the inhibitors of SMAD2/3 phosphorylation were reduced, indicative of mitochondrial ribosomal stress and increased TGF-β signaling. In patients undergoing aortic surgery, pre-operative levels of miR-542-3p/5p were positively correlated with muscle loss following surgery. Conclusion; Elevated miR-542-3p/5p may cause muscle atrophy in ICU patients through the promotion of mitochondrial dysfunction and activation of SMAD2/3 phosphorylation

    The differential importance of deep and shallow seagrass to Nekton assemblages of The Great Barrier Reef

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    Seagrass meadows are an important habitat for a variety of animals, including ecologically and socioeconomically important species. Seagrass meadows are recognised as providing species with nursery grounds, and as a migratory pathway to adjacent habitats. Despite their recognised importance, little is known about the species assemblages that occupy seagrass meadows of different depths in the coastal zone. Understanding differences in the distribution of species in seagrass at different depths, and differences in species diversity, abundance, biomass, and size spectra, is important to fully appreciate both the ecological significance and economic importance of these seagrass meadows. Here, we assess differences in the assemblage characteristics of fish, crustacea, and cephalopods (collectively, nekton) between deep ( > 9 m; Halophila spinulosa dominant) and shallow water ( < 2 m; Halodule uninervis and/or Zostera muelleri dominant) seagrass meadows of the central Great Barrier Reef coast of Queensland, Australia. Nekton assemblage structure differed between deep and shallow seagrass. Deeper meadows were typified by juvenile emperors (e.g., Lethrinus genivittatus), hairfinned leatherjacket (Paramonacanthus japonicus) and rabbitfish (e.g., Siganus fuscescens) in both biomass per unit effort (BPUE) and catch per unit effort (CPUE), whereas shallow meadows were typified by the green tiger prawn (Penaeus semisulcatus) and pugnose ponyfish (Secutor insidiator) in both BPUE and CPUE. Both meadow depths were distinct in their nekton assemblage, particularly for socioeconomically important species, with 11 species unique to both shallow and deep meadows. However, both meadow depths also included juveniles of socioeconomically important species found in adjacent habitats as adults. The total nekton CPUE was not different between deep and shallow seagrass, but the BPUE and body mass of individual animals were greater in deep than shallow seagrass. Size spectra analysis indicated that in both deep and shallow meadows, smaller animals predominated, even more so than theoretically expected for size spectra. Our findings highlight the unique attributes of both shallow and deeper water seagrass meadows, and identify the distinct and critically important role of deep seagrass meadows within the Great Barrier Reef World Heritage Area (GBRWHA) as a habitat for small and juvenile species, including those of local fisheries value

    Habitat complexity influences the structure of food webs in Great Barrier Reef seagrass meadows

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    Structural habitat complexity is a fundamental attribute influencing ecological food webs. Simplification of complex habitats occurs due to both natural and anthropogenic pressures that can alter productivity of food webs. Relationships between food web structure and habitat complexity may be influenced by multiple mechanisms, and untangling these can be challenging. We investigated whether (1) size spectra vary across a gradient of habitat complexity in seagrass meadows and (2) structural complexity changes the importance of different primary producers supporting the food web (determined using stable isotope analysis) in the Great Barrier Reef World Heritage Area. We found that moderately complex meadows had much steeper size spectra slopes, caused by a higher abundance of smaller animals and fewer larger animals, while meadows on either end of the complexity scale (low and a single meadow with very high complexity) had shallower slopes, indicative of a more balanced distribution of animal sizes across the spectrum. We also found that the importance of epiphytic algae as a food source was high in most meadows, despite the increase in seagrass surface area on which epiphytes could grow. The consistent importance of epiphytic algae suggests that the changes in the availability of different potential food sources did not affect food web structure. Our findings indicate that food web structure may change with variations in structural complexity because of changes in the abundance of smaller and/or larger animals. Food web structure and food sources are important determinants of the dynamic stability of food webs. Size spectra analysis is already used as a monitoring tool for assessing populations of key fisheries species in commercial fishing operations, and thus, we recommend using size spectra as a proxy for assessing the structure of the food webs in different types of seagrass meadows. Size spectra may be a useful indicator of how different meadows provide for ecosystem services such as fisheries

    Creation of 3D Digital Anthropomorphic Phantoms which Model Actual Patient Non-rigid Body Motion as Determined from MRI and Position Tracking Studies of Volunteers

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    Background: Patient motion during emission imaging can create artifacts in the reconstructed emission distributions, which may mislead the diagnosis. For example, in myocardial-perfusion imaging, these artifacts can be mistaken for defects. Various software and hardware approaches have been developed to detect and compensate for motion. There are various ways of testing the effectiveness of motion correction methods applied in emission tomography, including the use of realistic digital anthropomorphic phantoms. Purpose: The purpose of this study was to create 3D digital anthropomorphic phantoms based on MRI data of volunteers undergoing a series of clinically relevant motions. These phantoms with combined position tracking were used to investigate both imaging-data-driven and motion tracking strategies to estimate and correct for patient motion. Methods: MRI scans were obtained of volunteers undergoing a series of clinically relevant movements. During the MRI, the motions were recorded by near-infra-red cameras tracking using external markers on the chest and abdomen. Individual-specific extended cardiac-torso (XCAT) phantoms were created fit to our volunteer MRI imaging data representing pre- and post-motion states. These XCAT phantoms were then used to generate activity and attenuation distributions. Monte Carlo methods will then be performed to simulate SPECT acquisitions, which will be used to evaluate various motion estimation and correction strategies. Results: Three volunteers were scanned in the MRI with concurrent external motion tracking. Each volunteer performed five separate motions including an axial slide, roll, shoulder twist, spine bend, and arm motion. These MRI scans were then manually digitalized into 3D anthropomorphic XCAT phantoms. Activity and attenuation distributions were created for each XCAT phantom, representing fifteen individual-specific motions. Conclusions: Our results will be combined with the external motion tracking data to determine if external motion tracking accurately reflects heart position in patients undergoing cardiac SPECT imaging. This data will also be used to evaluate other motion correction methods in the future
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