137 research outputs found
Willingness to Pay for Water Availability in Northwest Arkansas
Resource /Energy Economics and Policy,
Performance Optimal and Robust Design of an Idle-Speed Controller Considering Physical Uncertainties
Modern passenger vehicles are equipped with a
great number of control functions targeting versatile performance
aspects like safe drive-ability, comfortable or sporty
ride concerning assistance systems or a proper adjustment of
engine control functions in order to prevent noise vibration
and harshness issues. In this paper a methodology for a
performance optimal and robust controller design is presented.
This methodology is applied on a given idle-speed controller
implementation using a detailed nonlinear drive train model
in closed loop considering physical parameter uncertainties.
The results are discussed with exemplary selected performance
measures
Hydrogen Peroxide - Material Compatibility Studied by Microcalorimetry
Environmental and toxicity concerns with current hypergolic propellants have led to a renewed interest in propellant grade hydrogen peroxide (HP) for propellant applications. Storability and stability has always been an issue with HP. Contamination or contact of HP with metallic surfaces may cause decomposition, which can result in the evolution of heat and gas leading to increased pressure or thermal hazards. The NASA Johnson Space Center White Sands Test Facility has developed a technique to monitor the decompositions of hydrogen peroxide at temperatures ranging from 25 to 60 C. Using isothermal microcalorimetry we have measured decomposition rates at the picomole/s/g level showing the catalytic effects of materials of construction. In this paper we will present the results of testing with Class 1 and 2 materials in 90 percent hydrogen peroxide
Three new mycoviruses identified in the apple replant disease (ARD)-associated fungus Rugonectria rugulosa
In this study, three new mycoviruses were identified co-infecting the apple replant disease (ARD)-associated root endophyte Rugonectria rugulosa. After dsRNA extraction, six viral fragments were visualized. Four fragments belong to a quadrivirus, which has a genome size of 17,166 bp. Each of the fragments of this quadrivirus has a single ORF encoding a protein. Two of these proteins are coat protein subunits, one ORF encodes the RdRp, and one protein has an unknown function. This virus was tentatively named rugonectria rugulosa quadrivirus 1 (RrQV1) as a member of the proposed new species Quadrivirus rugonectria. Another fragment represents the dsRNA intermediate form of a + ssRNA mitovirus with a genome size of 2410 nt. This virus encodes an RdRp and is tentatively called rugonectria rugulosa mitovirus 1 (RrMV1). RrMV1 is suggested as a member of a new species with the proposed name Mitovirus rugonectria. The sixth fragment belongs to the genome of an unclassified dsRNA virus tentatively called rugonectria rugulosa dsRNA virus 1 (RrV1). The monopartite dsRNA genome of RrV1 has a length of 8964 bp and contains two ORFs encoding a structure/gag protein and an RdRp. Full genomic sequences were determined and the genome structure as well as molecular properties are presented. After phylogenetic studies and sequence identity analyses, all three isolates are proposed as new mycoviruses. The results help to improve the understanding of the complexity of the factors involved in ARD and support the interest in mycoviral research. Subsequent analyses need to focus on the impact of mycoviruses on the biology and pathogenicity of ARD-associated fungi. The results of such studies could contribute to the development of mitigation strategies against the disease
First report of a chrysovirus infecting a member of the fungal genus Ilyonectria
The fungus Ilyonectria pseudodestructans belongs to the family Nectriaceae and was found to be part of the endophytic microbiome of apple trees (Malus x domestica, Borkh.) with apple replant disease (ARD). After dsRNA extraction, a mycoviral infection became evident. Here, we report the identification of a new virus, tentatively named “Ilyonectria pseudodestructans chrysovirus 1” (IpCV1), as the first member of the proposed new species “Alphachrysovirus ilyonectriae” within the genus Alphachrysovirus. This is the first report of a chrysovirus infecting a member of the fungal genus Ilyonectria. IpCV1 has a tripartite dsRNA genome with a total length of 8944 bp. The segments are 3439 bp, 2850 bp, and 2655 bp in length, and each dsRNA carries a single ORF. The encoded viral proteins are a 125.92-kDa RNA-dependent RNA polymerase, a 100.75-kDa coat protein, and one protein of unknown function with a predicted molecular mass of 93.04 kDa. The 5´ and 3´ UTRs are comparatively short and are 79 to 91 bp and 62 to 148 bp in length, respectively. This study provides the basis for further investigations of the impact of IpCV1 on its host and the etiology of ARD
Quantification Of The Efficiency Of Rumen Microbial Protein Synthesis In Steers Fed Green Tropical Grass
The rate of rumen microbial crude protein (MCP) supply to the intestines is a crucial element in the current rumen models to predict respond of ruminants to a certain diet. Data from tropical pastures always below predicted results from the existing rumen models. Thus, quantification of the rumen MCP supply from tropical grass will improve predictive rate under tropical feeding conditions. Four Brahman crossbred steers (457±20.1 kg) were used in a metabolism study. Pangola grass (Digitaria erianthe cv. Steudal) was harvested every morning and fed to the animals soon after. Parameters measured were EMPS, intake, fractional passage rates, and rumen ammonia concentration. The EMPS was estimated using purine derivative excretion in urine. Crude protein and water soluble carbohydrates content were 6.3 and 7.4% of dry matter (DM) respectively. DM intake was 1.6% live weight. Average rumen ammonia concentration was 69 mg/L whilst rumen passage rates were 7.84 and 6.92 %/h for fluid and solids respectively. EMPS was only 72 g MCP/kg digestible organic matter. It might be concluded that EMPS in steers consuming green pangola grass was below the minimum level for forage diets adopted in the current feeding standards
Molecular characterization of two new alternaviruses identified in members of the fungal family Nectriaceae
Since the first report in 2009, at least ten additional viruses have been identified and assigned to the proposed virus family Alternaviridae. Here we report two new mycoviruses tentatively assigned to this family, both identified as members of the fungal family Nectriaceae, which were isolated from surface-disinfected apple roots (Malus x domestica, Borkh.) affected by apple replant disease (ARD). ARD is a highly complex, worldwide-occurring disease resulting from plant reactions to a disturbed (micro)-biome and leads to high economic losses every year. The first alternavirus characterized in this study was identified in a Dactylonectria torresensis isolate. The virus was tentatively named dactylonectria torresensis alternavirus 1 (DtAV1) as the first member of the proposed new species Alternavirus dactylonectriae. The second virus was identified in an isolate of Ilyonectria robusta and was tentatively named ilyonectria robusta alternavirus 1 (IrAV1) as the first member of the proposed new species Alternavirus ilyonectriae. Full genomic sequences of the viruses were determined and are presented. Further, we found hints for putative components of a methyl transferase machinery using in silico approaches. This putative protein domain is encoded by segment 2. However, this result only establishes the basis for subsequent studies in which the function must be confirmed experimentally in vitro. Thus, this is the first study where a function is predicted to all three genomic segments within the group of the alternaviruses. These findings provide further insights into the virome of ARD-associated fungi and are therefore another brick in the wall of understanding the complexity of the disease
A high-flux BEC source for mobile atom interferometers
Quantum sensors based on coherent matter-waves are precise measurement
devices whose ultimate accuracy is achieved with Bose-Einstein condensates
(BEC) in extended free fall. This is ideally realized in microgravity
environments such as drop towers, ballistic rockets and space platforms.
However, the transition from lab-based BEC machines to robust and mobile
sources with comparable performance is a challenging endeavor. Here we report
on the realization of a miniaturized setup, generating a flux of quantum degenerate Rb atoms every 1.6s. Ensembles of atoms can be produced at a 1Hz rate. This is achieved by loading a
cold atomic beam directly into a multi-layer atom chip that is designed for
efficient transfer from laser-cooled to magnetically trapped clouds. The
attained flux of degenerate atoms is on par with current lab-based BEC
experiments while offering significantly higher repetition rates. Additionally,
the flux is approaching those of current interferometers employing Raman-type
velocity selection of laser-cooled atoms. The compact and robust design allows
for mobile operation in a variety of demanding environments and paves the way
for transportable high-precision quantum sensors.Comment: 22 pages, 6 figure
Design of a PI-Controller Based on Time-Domain Specification Utilizing the Parameter Space Approach
In automotive application PI and PID controllers are widely used. Commonly the controller parametrization is performed in a heuristic manner in the vehicle at different operating points. Model-based approaches offer many advantages like a reduced effort of the design process and a more systematically investigation of the parameter set. Circumventing experiments at the vehicle is not feasible, however the goal is to achieve a significant reduction of this part of work. The aim of this paper is to find the controller parameter region, that ensures compliance with defined measures of the controller performance in time domain. On the basis of the parameter space approach these measures need to be transferred into the s-domain, which is shown exemplary for a second order system and a PI-controlled integrator system. The latter serves as a simple vehicle drive train model for the design of the engine idle speed controller
Loss of intra-islet heparan sulfate is a highly sensitive marker of type 1 diabetes progression in humans
Type 1 diabetes (T1D) is an autoimmune disease in which insulin-producing beta cells in pancreatic islets are progressively destroyed. Clinical trials of immunotherapies in recently diagnosed T1D patients have only transiently and partially impacted the disease course, suggesting that other approaches
are required. Our previous studies have demonstratedthat heparan sulfate (HS), a
glycosaminoglycan conventionally expressed in extracellular matrix, is present at high levels
inside normal mouse beta cells. Intracellular HS was shownto be critical for beta cell survival and
protection from oxidative damage. T1D development
in Non-Obese Diabetic (NOD) mice correlated with loss of islet HS and was prevented by
inhibiting HS degradation by the endoglycosidase, heparanase. In this study we investigated
the distribution of HS and heparan sulfate proteoglycan (HSPG) core proteins in normal
human islets, a role for HS in human beta cell viability and the clinical relevance of intraislet
HS and HSPG levels, compared to insulin, in human T1D. In normal human islets, HS
(identified by 10E4 mAb) co-localized with insulin but not glucagon and correlated with the
HSPG core proteins for collagen type XVIII (Col18) and syndecan-1 (Sdc1). Insulin-positive
islets of T1D pancreases showed significant loss of HS, Col18 and Sdc1 and heparanase
was strongly expressed by islet-infiltrating leukocytes. Human beta cells cultured with HS
mimetics showed significantly improved survival and protection against hydrogen peroxideinduced death, suggesting that loss of HS could contribute to beta cell death in T1D. We conclude that HS depletion in beta cells, possibly due to heparanase produced by insulitis leukocytes, may function as an important
mechanism in the pathogenesis of human T1D.
Our findings raise the possibility that intervention therapy with dual activity HS replacers/
heparanase inhibitors could help to protect the residual beta cell mass in patients recently
diagnosed with T1D.: This work was supported by a National
Health and Medical Research Council of Australia
(NHMRC; https://www.nhmrc.gov.au/)/Juvenile
Diabetes Research Foundation (JDRF) Special
Program Grant in Type 1 Diabetes (#418138), The
Canberra Hospital Private Practice Fund (http://
www.health.act.gov.au/research-publications/research/ppf-major-grants), JDRF nPOD Research
Grant (#25-2010-716; http://www.jdrf.org), JDRF
Research Grant (#47-2012-746) and NHMRC
Project Grant (#1043284
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