1,132 research outputs found
Higher-order-in-spin interaction Hamiltonians for binary black holes from source terms of Kerr geometry in approximate ADM coordinates
The Kerr metric outside the ergosphere is transformed into ADM coordinates up
to the orders and , respectively in radial coordinate and
reduced angular momentum variable , starting from the Kerr solution in
quasi-isotropic as well as harmonic coordinates. The distributional source
terms for the approximate solution are calculated. To leading order in linear
momenta, higher-order-in-spin interaction Hamiltonians for black-hole binaries
are derived.Comment: REVTeX4, 20 pages, typos corrected in Eq. (124) and (130
Standing dead trees contribute significantly to carbon budgets in Australian savannas
Previous estimates of greenhouse gas emissions from Australian savanna fires have incorporated on-ground dead wood but ignored standing dead trees. However, research from eucalypt woodlands in southern Queensland has shown that the two pools of dead wood burn at similar rates. New field data from semiarid savannas across northern Australia confirmed that standing dead trees comprise about four times the mass of on-ground dead wood. Further, the proportion of total woody biomass comprising dead wood increases with decreasing fire frequency and a decreasing proportion of late dry season (August to December) fires. This gives scope for increasing the carbon stock in the dead wood pool with a reduced fire frequency. Following a previously published approach to quantify total dead wood loads in savannas, new and previously collected data on tree stand structures were used across the whole savanna zone to quantify dead wood loads in equilibrium with historic fire regimes. New parameters are presented for calculating dead wood dynamics including dead trees in Australia's savannas. © 2020 IAWF
Seasonality Directs Contrasting Food Collection Behavior and Nutrient Regulation Strategies in Ants
Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant
Occurrence and diversity of Xanthomonas campestris pv. campestris in vegetable brassica fields in Nepal
Black rot caused by Xanthomonas campestris pv. campestris was found in 28 sampled cabbage fields in five major cabbage-growing districts in Nepal in 2001 and in four cauliflower fields in two districts and a leaf mustard seed bed in 2003. Pathogenic X. campestris pv. campestris strains were obtained from 39 cabbage plants, 4 cauliflower plants, and 1 leaf mustard plant with typical lesions. Repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR) using repetitive extragenic palindromic, enterobacterial repetitive intergenic consensus, and BOX primers was used to assess the genetic diversity. Strains were also race typed using a differential series of Brassica spp. Cabbage strains belonged to five races (races 1, 4, 5, 6, and 7), with races 4, 1, and 6 the most common. All cauliflower strains were race 4 and the leaf mustard strain was race 6. A dendrogram derived from the combined rep-PCR profiles showed that the Nepalese X. campestris pv. campestris strains clustered separately from other Xanthomonas spp. and pathovars. Race 1 strains clustered together and strains of races 4, 5, and 6 were each split into at least two clusters. The presence of different races and the genetic variability of the pathogen should be considered when resistant cultivars are bred and introduced into regions in Nepal to control black rot of brassicas
Price adjustment in the London housing market
Recent research into the dynamic adjustment of prices within the London housing market is extended via the application of a novel two-step procedure. Combining the non-parametric analysis of the ranking distributions of the levels and changes in house prices with the application of a cross-sectional convergence technique, the analysis results in the detection of a three-tier system in which highly significant convergence clubs are identified within borough-level data. These findings contrast with both the divergence apparent when considering all boroughs and the failure of previous research to identify convergent groupings. The novelty of the empirical methods is supplemented by a discussion of various theoretical factors such as gentrification, displaced demand, immigration, foreign investment and criminal activity in relation to the findings obtained
Recent Decisions
Recent Decisions
Admiralty--Time Charter--Shipowner\u27s Contractual Right to Withdraw Services of Vessel upon Charterer\u27s Failure to Provide Punctual Payment is not Extinguished by Late Tender of Payment
Richard F. Cook, Jr.
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Antitrust--Treble Damages--A Foreign Sovereign is a Person entitled to Sue under Section 4 of the Clayton Act
Edward Cage Brewer, III
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Customs search of International Mail--A Customs Search of International Mail is Authorized by 19 C.F.R. § 145.2 and Incorporates the Reasonable Cause to Suspect Requirement of 19 U.S.C. § 482
Daniel R. Wofsey
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Jurisdiction and Procedure--Discovery--Party unable to comply with Discovery Order which Contravenes Foreign Nondisclosure Law is not in Contempt of Court
Sue D. Sheridan
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Treaties--Drugs and Narcotics--Single Convention on Narcotic Drugs permits the United States to Place fewer Restrictions on Separated Marijuana Leaves
Steven M. Morga
\u3ci\u3eVarroa destructor\u3c/i\u3e Mites Vector and Transmit Pathogenic Honey Bee Viruses Acquired From an Artificial Diet
The ectoparasitic mite Varroa destructoris one of the most destructive pests of the honey bee (Apis mellifera) and the primary biotic cause of colony collapse in many regions of the world. These mites inflict physical injury on their honey bee hosts from feeding on host hemolymph and fat body cells/cellular components, and serve as the vector for deadly honey bee viruses, including Deformed wing virus (DWV) and the related Varroa destructor virus-1 (VDV-1) (i.e., DWV-like viruses). Studies focused on elucidating the dynamics of Varroa-mediated vectoring and transmission of DWV-like viruses may be confounded by viruses present in ingested host tissues or the mites themselves. Here we describe a system that includes an artificial diet free of insect tissue-derived components for maintaining Varroa mites for in vitro experimentation. Using this system, together with the novel engineered cDNA clone-derived genetically tagged VDV-1 and wild-type DWV, we demonstrated for the first time that Varroa mites provided an artificial diet supplemented with engineered viruses for 36 hours could acquire and transmit sufficient numbers of virus particles to establish an infection in virus-naïve hosts. While the in vitro system described herein provides for only up to five days of mite survival, precluding study of the long-term impacts of viruses on mite health, the system allows for extensive insights into the dynamics of Varroa-mediated vectoring and transmission of honey bee viruses
Gene Expression and Functional Analyses of Odorant Receptors in Small Hive Beetles (Aethina tumida).
Olfaction is key to many insects. Odorant receptors (ORs) stand among the key chemosensory receptors mediating the detection of pheromones and kairomones. Small hive beetles (SHBs), Aethina tumida, are parasites of social bee colonies and olfactory cues are especially important for host finding. However, how interactions with their hosts may have shaped the evolution of ORs in the SHB remains poorly understood. Here, for the first time, we analyzed the evolution of SHB ORs through phylogenetic and positive selection analyses. We then tested the expression of selected OR genes in antennae, heads, and abdomens in four groups of adult SHBs: colony odor-experienced/-naive males and females. The results show that SHBs experienced both OR gene losses and duplications, thereby providing a first understanding of the evolution of SHB ORs. Additionally, three candidate ORs potentially involved in host finding and/or chemical communication were identified. Significantly different downregulations of ORs between the abdomens of male and female SHBs exposed to colony odors may reflect that these expression patterns might also reflect other internal events, e.g., oviposition. Altogether, these results provide novel insights into the evolution of SHB ORs and provide a valuable resource for analyzing the function of key genes, e.g., for developing biological control. These results will also help in understanding the chemosensory system in SHBs and other beetles
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