244 research outputs found
Circuit protection devices for transient suppression
The Electromer Corporation has developed a series of transient voltage suppression components based on a patented, specially formulated PolyClamp (trademark) material. PolyClamp components are a new class of transient voltage surge suppressors that extend the range of protection offered by transients protectors. The PolyClamp transient surge suppressors provide low capacitance, high energy capability, and packaging flexibility. A wide variety of applications can be protected. A tube and ferrule configuration was designed to be used with MIL/Aerospace style connectors and is designed to meet the applicable environmental, mechanical, and electrical requirements as defined by the United States and European defence standards performance requirements. Here, PolyClamp is compared with current transient surge suppressors. Typical performance and design are discussed
Restoration action effectiveness: employing the concept of net ecosystem improvement
The mission statement of the Northwest Straits Initiative includes ‘improving ecosystem health’ of the Strait of Juan de Fuca and Northern Puget Sound by restoring and protecting natural habitats and resources. For the Initiative, and many other programs, defining ‘ecosystem health’ and developing relevant and measureable health metrics is problematic, and yet critical to both assessing program action effectiveness as well as justifying investments. The Initiative is exploring utilizing the concept of net ecosystem improvement (NEI) to summarize results of actions and couch the results in a broader ecosystem perspective. Net improvement is defined as following development; there is an increase in the size and natural functions of an ecosystem or natural components of the ecosystem (Thom et al. 2005. Restoration Ecol. v. 13). Conceptual models are used to summarize knowledge and guide actions to improve the ecosystem. NEI is calculated by estimating the change in function times the change in area over which this change in function occurred including both temporal and spatial aspects. For example, the anchor out zone project managed by the Jefferson County Marine Resources Committee in Port Townsend protects 21.6ha (52 acres) of eelgrass. Without this protection most if not all of the eelgrass would be lost. Using data from other areas, we estimated that 3,998 - 66,077 Dungeness crab (primarily juveniles) and net production by eelgrass of 2,083 metric tons wet wt y-1, are protected. Based on WDNR monitoring (Christiaen et al. 2017), this area of eelgrass protected amounts to 0.5 – 0.8% of the total eelgrass area in the Straits, and 0.5% of the Puget Sound Partnership 2020 eelgrass recovery goal of ~4000ha. Estimating NEI and placing the results in a broader ecosystem perspective is possible for many actions taken by the Initiative’s Marine Resource Committees, and may be appropriate for other programs
Ecology of Feral Pigeons: Population Monitoring, Resource Selection, and Management Practices
Feral pigeons (Columba livia) are typically ignored by ornithologists but can be found roosting in the thousands within cities across the world. Pigeons have been known to spread zoonoses, through ectoparasites and excrement they produce. Along with disease, feral pigeons have an economic impact due to the cost of cleanup and maintenance of human infrastructure. Many organizations have tried to decrease pigeon abundances through euthanasia or use of chemicals that decrease reproductive output. However, killing pigeons has been unsuccessful in decreasing abundance, and chemical inhibition can be expensive and must be used throughout the year. A case study at Texas Tech University has found that populations fluctuate throughout the year, making it difficult to manage numbers. To successfully decrease populations, it is important to have a multifaceted approach that includes removing necessary resources (i. e. nest sites and roosting areas) and decreasing the number of offspring through humane techniques
Dietary carbohydrate restriction as the first approach in diabetes management:Critical review and evidence base
AbstractThe inability of current recommendations to control the epidemic of diabetes, the specific failure of the prevailing low-fat diets to improve obesity, cardiovascular risk, or general health and the persistent reports of some serious side effects of commonly prescribed diabetic medications, in combination with the continued success of low-carbohydrate diets in the treatment of diabetes and metabolic syndrome without significant side effects, point to the need for a reappraisal of dietary guidelines. The benefits of carbohydrate restriction in diabetes are immediate and well documented. Concerns about the efficacy and safety are long term and conjectural rather than data driven. Dietary carbohydrate restriction reliably reduces high blood glucose, does not require weight loss (although is still best for weight loss), and leads to the reduction or elimination of medication. It has never shown side effects comparable with those seen in many drugs. Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results. The insistence on long-term randomized controlled trials as the only kind of data that will be accepted is without precedent in science. The seriousness of diabetes requires that we evaluate all of the evidence that is available. The 12 points are sufficiently compelling that we feel that the burden of proof rests with those who are opposed
Gene content evolution in the arthropods
Arthropods comprise the largest and most diverse phylum on Earth and play vital roles in nearly every ecosystem. Their diversity stems in part from variations on a conserved body plan, resulting from and recorded in adaptive changes in the genome. Dissection of the genomic record of sequence change enables broad questions regarding genome evolution to be addressed, even across hyper-diverse taxa within arthropods. Using 76 whole genome sequences representing 21 orders spanning more than 500 million years of arthropod evolution, we document changes in gene and protein domain content and provide temporal and phylogenetic context for interpreting these innovations. We identify many novel gene families that arose early in the evolution of arthropods and during the diversification of insects into modern orders. We reveal unexpected variation in patterns of DNA methylation across arthropods and examples of gene family and protein domain evolution coincident with the appearance of notable phenotypic and physiological adaptations such as flight, metamorphosis, sociality, and chemoperception. These analyses demonstrate how large-scale comparative genomics can provide broad new insights into the genotype to phenotype map and generate testable hypotheses about the evolution of animal diversity
Why sequence all eukaryotes?
Life on Earth has evolved from initial simplicity to the astounding complexity we experience today. Bacteria and archaea have largely excelled in metabolic diversification, but eukaryotes additionally display abundant morphological innovation. How have these innovations come about and what constraints are there on the origins of novelty and the continuing maintenance of biodiversity on Earth? The history of life and the code for the working parts of cells and systems are written in the genome. The Earth BioGenome Project has proposed that the genomes of all extant, named eukaryotes-about 2 million species-should be sequenced to high quality to produce a digital library of life on Earth, beginning with strategic phylogenetic, ecological, and high-impact priorities. Here we discuss why we should sequence all eukaryotic species, not just a representative few scattered across the many branches of the tree of life. We suggest that many questions of evolutionary and ecological significance will only be addressable when whole-genome data representing divergences at all of the branchings in the tree of life or all species in natural ecosystems are available. We envisage that a genomic tree of life will foster understanding of the ongoing processes of speciation, adaptation, and organismal dependencies within entire ecosystems. These explorations will resolve long-standing problems in phylogenetics, evolution, ecology, conservation, agriculture, bioindustry, and medicine
Low spin spectroscopy of neutron-rich 43,44,45Cl via {\beta} and (\beta}n decay
{\beta} decay of neutron-rich isotopes 43,45 S,studied at the National
Superconducting Cyclotron Laboratory is reported here. {\beta} delayed {\gamma}
transitions were detected by an array of 16 clover detectors surrounding the
Beta Counting Station which consists of a 40x40 Double Sided Silicon Strip
Detector followed by a Single Sided Silicon Strip Detector. {\beta} decay
half-lives have been extracted for 43,45 S by correlating implants and decays
in the pixelated implant detector with further coincidence with {\gamma}
transitions in the daughter nucleus. The level structure of 43,45 Cl is
expanded by the addition of 20 new {\gamma} transitions in 43Cl and 8 in 45 Cl
with the observation of core excited negative-parity states for the first time.
For 45 S decay, a large fraction of the {\beta} decay strength goes to delayed
neutron emission populating states in 44 Cl which are also presented.
Comparison of experimental observations is made to detailed shell-model
calculations using the SDPFSDG-MU interaction to highlight the role of the
diminished N = 28 neutron shell gap and the near degeneracy of the proton s 1/2
and d 3/2 orbitals on the structure of the neutron-rich Cl isotopes. The
current work also provides further support to a ground state spin-parity
assignment of 3/2 + in 45 Cl
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