270 research outputs found
Recommended from our members
Sourcebook on the Production of Electricity From Geothermal Energy. Draft: Chapter 4, Section 4. 4. Status of the Development of the Total Flow System for Electric Power Production From Geothermal Energy. [Includes Glossary]
Discussion is presented under the following section headings: introduction; characteristics of wellhead fluid; energy conversion concepts (including subsections, the flashed steam system, the total flow concept, and comparison of total flow expanders); brine chemistry effects; a possible total flow system design; and references, bibliography, glossary, and figures. (JGB
Ergot: A New Disease Threat to Sorghum in the Americas and Australia
Sorghum, Sorghum bicolor (L.) Moench, is the world’s fifth most important cereal crop, cultivated on about 45 million hectares for food, feed, beverage, and fodder. The most significant technological change since the 1960s has been the development and use of F1 hybrid seed (14), which has lead to a dramatic
improvement in the crop’s productivity. Sorghum cultivation in intensive, commercialized systems where yields average 3 to 5 t ha-1 relies almost totally on hybrid seed. In contrast, yields vary widely and average less than 1 t ha-1 in low-input production systems
Antimicrobial susceptibility profiles of Staphylococcus aureus isolates recovered from humans, environmental surfaces, and companion animals in households of children with community-onset methicillin-resistant S. aureus infections
Our objective was to determine the antibiotic susceptibility profiles of Staphylococcus aureus isolates recovered from 110 households of children with community-onset methicillin-resistant S. aureus (MRSA) infections. Cultures were obtained from household members, household objects, and dogs and cats, yielding 1,633 S. aureus isolates. The S. aureus isolates were heterogeneous, although more than half were methicillin resistant. The highest proportion of MRSA was found in bathrooms. The majority of isolates were susceptible to antibiotics prescribed in outpatient settings
Assessment of the Degree of Willingness to Change from Motorized Travel Modes to Walking or Cycling
This paper presents an analysis of the degree of willingness to change from motorized travel modes to walking or cycling. The aim of the analysis is to reduce uncertainty between stated willingness to change and real shifts from car or transit to nonmotorized transportation modes. Data were collected in the city of Valencia, Spain, through a novel data collection effort based on multiple survey methods. Respondents traveling by car or transit were asked about their willingness to change to walking or cycling under the implementation of improvement measures to be selected. Then a hypothetical scenario was presented to respondents who stated a willingness to change; in the scenario, the previously selected measures were implemented and respondents were supposed to be cycling or walking. In addition, the costs of their usual travel mode were gradually reduced until they gave up cycling or walking. Those who decided to keep on walking or cycling were assumed to have a strong willingness to change. A statistical analysis performed with Heckman's sample selection model permitted identification of demographic, socioeconomic, and travel-related factors influencing the degree of willingness to change. Results revealed that car users presented a stronger willingness to switch to walking or cycling than transit users. In addition, older respondents showed a stronger willingness to change to both walking and cycling. Work- and school-related journeys were less associated with walking than noncommuting journeys, but they were more related to cycling. Policy implications of the results are highlighted.Ferrer, S.; Ruiz Sánchez, T. (2013). Assessment of the Degree of Willingness to Change from Motorized Travel Modes to Walking or Cycling. Transportation Research Record. (2382):112-120. doi:10.3141/2382-13S112120238
Chaotic and Clumpy Galaxy Formation in an Extremely Massive Reionization-era Halo
© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. https://creativecommons.org/licenses/by/4.0/Abstract: The SPT 0311–58 system at z = 6.900 is an extremely massive structure within the reionization epoch and offers a chance to understand the formation of galaxies at an extreme peak in the primordial density field. We present 70 mas Atacama Large Millimeter/submillimeter Array observations of the dust continuum and [C ii] 158 μm emission in the central pair of galaxies and reach physical resolutions of ∼100–350 pc, among the most detailed views of any reionization-era system to date. The observations resolve the source into at least a dozen kiloparsec-size clumps. The global kinematics and high turbulent velocity dispersion within the galaxies present a striking contrast to recent claims of dynamically cold thin-disk kinematics in some dusty galaxies just 800 Myr later at z ∼ 4. We speculate that both gravitational interactions and fragmentation from massive parent disks have likely played a role in the overall dynamics and formation of clumps in the system. Each clump individually is comparable in mass to other 6 < z < 8 galaxies identified in rest-UV/optical deep field surveys, but with star formation rates elevated by a factor of ~3-5. Internally, the clumps themselves bear close resemblance to greatly scaled-up versions of virialized cloud-scale structures identified in low-redshift galaxies. Our observations are qualitatively similar to the chaotic and clumpy assembly within massive halos seen in simulations of high-redshift galaxies.Peer reviewe
The domestication of SARS-CoV-2 into a seasonal infection by viral variants
IntroductionThe COVID-19 pandemic was caused by the zoonotic betacoronavirus SARS-CoV-2. SARS-CoV-2 variants have emerged due to adaptation in humans, shifting SARS-CoV-2 towards an endemic seasonal virus. We have termed this process ‘virus domestication’.MethodsWe analyzed aggregate COVID-19 data from a publicly funded healthcare system in Canada from March 7, 2020 to November 21, 2022. We graphed surrogate calculations of COVID-19 disease severity and SARS-CoV-2 variant plaque sizes in tissue culture.Results and DiscussionMutations in SARS-CoV-2 adapt the virus to better infect humans and evade the host immune response, resulting in the emergence of variants with altered pathogenicity. We observed a decrease in COVID-19 disease severity surrogates after the arrival of the Delta variant, coinciding with significantly smaller plaque sizes. Overall, we suggest that SARS-CoV-2 has become more infectious and less virulent through viral domestication. Our findings highlight the importance of SARS-CoV-2 vaccination and help inform public policy on the highest probability outcomes during viral pandemics
Bridging the Gulf: Phytophthora and Downy Mildews Are Connected by Rare Grass Parasites
Downy mildews and root and foliar rots caused by Phytophthora are among the most destructive plant pathogens and therefore have attracted considerable attention during the past two decades. Although it has been realized that a close phylogenetic relationship exists, so far sharp distinction has been made between the obligate biotrophic downy mildews and the hemibiotrophic Phytophthora. In the study presented here, it is shown that a continuum of character states from hemibiotrophic Phytophthora species to obligate biotrophic downy mildews is present. Intermediate character states between downy mildews and Phytophthora species exist in several rare parasites of grasses, which are not embedded within the major clades of the downy mildews but are placed sister to these, with unresolved affinities to both these clades and to Phytophthora. They still have retained traits hitherto thought to be exclusive for Phytophthora. A careful review of previous research is presented and it is highlighted that uniquely for downy mildews, Poakatesthia may form an intracellular mycelium, growing through several host cells. In addition, scanning electron microscopy reveals that sporangiophore growth is not determinate in Viennotia and that outgrowth from sporangiophores is very similar to Phytophthora infestans. It is concluded that the sharp morphological distinction between downy mildews and Phytophthora species (that are often placed in separate families and even different orders), is rather artificial, since all features thought to be exclusive to Phytophthora or the downy mildews are united in the rare grass-parasitizing down mildew genera Viennotia and Poakatesthia and the enigmatic genus Sclerophthora. Therefore, several paradigms regarding the distinction between Phytophthora and the downy mildews need to be reconsidered
Coordination of microtubule and microfilament dynamics by Drosophila Rho1, Spire, and Cappuccino
The actin nucleation factors Spire and Cappuccino regulate the onset of ooplasmic
streaming in Drosophila1-5. Although this streaming event is microtubule-based, actin
assembly is required for its timing. It is not understood how the interaction of
microtubules and microfilaments is mediated in this context. Here we demonstrate that
Cappuccino and Spire have microtubule and microfilament crosslinking activity. The spire
locus encodes several distinct protein isoforms (SpireA, SpireC, and SpireD). SpireD was
recently shown to nucleate actin, but the activity of the other isoforms has not been
addressed. We find that SpireD does not have crosslinking activity, while SpireC is a
potent crosslinker. We show that SpireD binds to Cappuccino and inhibits Factin/
microtubule crosslinking, and activated Rho1 abolishes this inhibition, establishing a
mechanistic basis for the regulation of Capu and Spire activity. We propose that Rho1,
cappuccino and spire are elements of a conserved developmental cassette that is capable of
directly mediating crosstalk between microtubules and microfilaments
- …