946 resultados para Fresnel number


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: After Rehab, Vessel Starts Over in Alaska The latest addition to the Refuge System’s fleet of vessels in Alaska spent much of its life on the wrong side of the law. In Arizona, Refuges Are Oases for Fish Fish in the desert? Yes. At San Bernardino and Leslie Canyon National Wildlife Refuges, protecting fish is in the establishing mission. FOCUS: Marine National Monuments The four marine national monuments are among the Refuge System’s most distinctive components. As such, they present special challenges, rare opportunities and unparalleled beauty. Can You Hear Me Now? Looking for a low-cost way to connect with visitors? Try a cellphone tour. It’s easy to set up.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Surveys of commercial markets combined with molecular taxonomy (i.e. molecular monitoring) provide a means to detect products from illegal, unregulated and/or unreported (IUU) exploitation, including the sale of fisheries bycatch and wild meat (bushmeat). Capture-recapture analyses of market products using DNA profiling have the potential to estimate the total number of individuals entering the market. However, these analyses are not directly analogous to those of living individuals because a ‘market individual’ does not die suddenly but, instead, remains available for a time in decreasing quantities, rather like the exponential decay of a radioactive isotope. Here we use mitochondrial DNA (mtDNA) sequences and microsatellite genotypes to individually identify products from North Pacific minke whales (Balaenoptera acutorostrata ssp.) purchased in 12 surveys of markets in the Republic of (South) Korea from 1999 to 2003. By applying a novel capture-recapture model with a decay rate parameter to the 205 unique DNA profiles found among 289 products, we estimated that the total number of whales entering trade across the five-year survey period was 827 (SE, 164; CV, 0.20) and that the average ‘half-life’ of products from an individual whale on the market was 1.82 months (SE, 0.24; CV, 0.13). Our estimate of whales in trade (reflecting the true numbers killed) was significantly greater than the officially reported bycatch of 458 whales for this period. This unregulated exploitation has serious implications for the survival of this genetically distinct coastal population. Although our capture-recapture model was developed for specific application to the Korean whale-meat markets, the exponential decay function could be modified to improve the estimates of trade in other wildmeat or fisheries markets or abundance of living populations by noninvasive genotyping.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Optical networks based on passive star couplers and employing wavelength-division multiplexing (WDhf) have been proposed for deployment in local and metropolitan areas. Amplifiers are required in such networks to compensate for the power losses due to splitting and attenuation. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus optical amplifier placement becomes a challenging problem. The general problem of minimizing the total amplifier count, subject to the device constraints, is a mixed-integer non-linear problem. Previous studies have attacked the amplifier placement problem by adding the “artificial” constraint that all wavelengths, which are present at a particular point in a fiber, be at the same power level. In this paper, we present a method to solve the minimum amplifier- placement problem while avoiding the equally powered- wavelength constraint. We demonstrate that, by allowing signals to operate at different power levels, our method can reduce the number of amplifiers required in several small to medium-sized networks.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: White Nose Syndrome News CWD Found in Virginia Serosurveys of Feral Swine AI Serology in Wild Birds Chagas Disease Studies SCWDS Bont Tick Surveillance Brain Tumor in Deer Exotic Animal Imports and Public Health Loss of Two SCWDS Friends

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: Piroplasmosis Hits Missouri Horses Cytauxzoon felis in Wild Felids SCIF & Mossy Oak Fund HD Research Hardware Disease in a Key Deer Wildlife Poisoning in Kansas Swine Brucellosis Infects Hog Hunters SCWDS Personnel Changes NWHC Has New Director New USDI Publication on Bats Recent SCWDS Publications Available

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: Clams & AI Virus SCWDS Funded to Study WNS USDA Program Changes Proposed TB in Captive Cervids CWD Prions in Deer Feces TWS Position Statement on Lead WDA Awards For SCWDS Staff New Brochure for Hog Hunters

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: USDA Seeks Comments on New CWD Rule Some of the Intricacies of CWD 3rd International CWD Symposium White Nose Syndrome Update Wildlife Poisoning in Kansas Salmonellosis in Your Backyard Trichomonosis in Songbirds Dr. Al Franzmann Staff & Student Recognition

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: HD in 2007: A Year to Remember Ecology of AIV in Shorebirds New USDA Brucellosis Proposal TWS Seeks Comments on Draft Lead Policy Unusual Eagle Death New SCWDS Grad Students Tennessee Director Retiring 3rd International CWD Symposium Another SCWDS Student Award

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: Piroplasmosis in Florida Horses Bovine TB Update Newcastle Disease in Cormorants Frog Virus in a Box Turtle SCWDS Vesicular Stomatitis Research Update Faculty and Staff Changes at SCWDS Lead Study Results Reported Lead Ammo and Tackle Review Our Energizer Bunny

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: Orbiviruses New & Old - What Do We Need to Know? Orbivirus Vector Surveys Studies on H5N1 HPAI Virus in Swans and Geese Dr. Justin Brown Awards Impacted Turkey Gizzard Regional Disease Workshops in 2008-09 Dove Disease Research at SCWDS Some Staff Changes

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: SCWDS History Continued: The Domestic Animal Connection WNV Still With Us: Other Arboviruses May Follow Avian Influenza Update – Spring 2007 Scholarship in Memory of Ed Couvillion Chronic Lead Poisoning in Raptors Unusual Deer Tumor Kevin Keel Receives Award New Edition of Wild Bird Diseases Book

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Table of Contents: SCWDS Celebrates 50 Years More Bovine TB in Minnesota Developments in CWD Surveillance and Research Federal CWD Rule Update Tularemia in Backyard Wildlife Osteochondromas in Two Deer Invasive Exotic Animals in the Southeast New Field Manual Sales