Wolves and Humans

TRY TO IMAGINE a small group of wolves sitting at a table engaged in vigorous debate. These wolves are from various parts of the globe and are perhaps a bit more scholarly than most. In fact, they are especially knowledgeable about the biology of that notorious two-legged species, Homo sapiens. They have been brought together to document their relationship with humans over the last several millennia. Pause for a few moments and consider what they might say ... Perhaps the wolves\u27 discussion would chronicle the evils of the human species, including details of atrocities committed against lupine ancestors down through the centuries. They might discuss the bizarre workings of the human imagination and the hopeless confusion of fact and fiction about wolf relationships with humans. The discussion might also express admiration for the way early humans respected wolves and imitated their living in family bands, maintaining pair bonds for years at a time, communicating in complex ways, and hunting cooperatively. The effects of advances in human technology might be detailed. The recent and long-awaited legal protection for wolves and the soaring popularity of wolves among some humans would certainly deserve mention. After an exhaustive review of the wolf-human relationship, the wolves might finally conclude that it has taken so many forms, depending on time and place, that generalizations are impossible

PCR-Directed Formation of Viral Hybridsin Vitro

AbstractWhen constructing viruses that have desired hybrid phenotypes, anticipated difficulties include the nonviability of many, possibly most, of the hybrid genomes that can be constructed by incorporation of DNA fragments. Therefore, many different hybrid genomes may have to be constructed in order to find one that is viable. To perform this combinatorial work in a single experiment, we have used bacteriophage T7-infected cell extracts to transfer DNAin vitro.In an extract, we have incubated T7 DNA, together with DNA obtained by polymerase chain reaction (PCR) amplification of the gene (gene 17) for the tail fiber of the T7-related bacteriophage, T3. Afterin vitropackaging of DNA in the extract, hybrid progeny bacteriophage were detected by probing with a T3-specific oligonucleotide; hybrids are found at a frequency of 0.1%. By determination of the nucleotide sequence of the entire gene 17 of 14 independently isolated hybrids, both right and left ends of the PCR fragment are found to be truncated in all hybrids. For all 14 hybrids, the right end is in the same location; the left end is found at 3 different locations. The nonrandom location of the ends is explained by selection among different inserts for viability; that is, most of the hybrid genomes are nonviable. Some hybrids acquire from T3 the desirable phenotype of nonadherence to agarose gels during agarose gel electrophoresis

The identity, distribution, and impacts of non-native apple snails in the continental United States

<p>Abstract</p> <p>Background</p> <p>Since the mid 1990s populations of non-native apple snails (Ampullariidae) have been discovered with increasing frequency in the continental United States. Given the dramatic effects that introduced apple snails have had on both natural habitats and agricultural areas in Southeast Asia, their introduction to the mainland U.S. is cause for concern. We combine phylogenetic analyses of mtDNA sequences with examination of introduced populations and museum collections to clarify the identities, introduced distributions, geographical origins, and introduction histories of apple snails.</p> <p>Results</p> <p>Based on sampling to date, we conclude there are five species of non-native apple snails in the continental U.S. Most significantly, we recognize three species within what has been called the channeled apple snail: <it>Pomacea canaliculata </it>(California and Arizona), <it>Pomacea insularum</it>, (Florida, Texas, and Georgia) and <it>Pomacea haustrum </it>(Florida). The first established populations of <it>P. haustrum </it>were discovered in the late 1970s in Palm Beach County Florida, and have not spread appreciably in 30 years. In contrast, populations of <it>P. insularum </it>were established in Texas by 1989, in Florida by the mid to late 1990s, and in Georgia by 2005, and this species continues to spread rapidly. Most introduced <it>P. insularum </it>haplotypes are a close match to haplotypes from the Río Uruguay near Buenos Aires, indicating cold tolerance, with the potential to spread from Florida, Georgia, and Texas through Louisiana, Alabama, Mississippi, and South Carolina. <it>Pomacea canaliculata </it>populations were first discovered in California in 1997. Haplotypes of introduced <it>P. canaliculata </it>match native-range haplotypes from near Buenos Aires, Argentina, also indicating cold tolerance and the potential to establish farther north.</p> <p>Conclusion</p> <p>The term "channeled apple snail" is descriptive of a morphology found in many apple snail species. It does not identify a single species or a monophyletic group. Clarifying species identifications permits a more accurate assessment of introduction histories and distributions, and provides a very different picture of the tempo and pattern of invasions than was inferred when the three species with channeled sutures were considered one. Matching introduced and native-range haplotypes suggests the potential for range expansion, with implications for native aquatic ecosystems and species, agriculture, and human health.</p

Design and test of a small single stage turbine

http://www.archive.org/details/designtestofsmal00dearU.S. Navy (U.S.N.) authors

Economic Perspectives on GMO Market Segregation

None

A hybrid double-dot in silicon

We report electrical measurements of a single arsenic dopant atom in the tunnel-barrier of a silicon SET. As well as performing electrical characterization of the individual dopant, we study series electrical transport through the dopant and SET. We measure the triple points of this hybrid double dot, using simulations to support our results, and show that we can tune the electrostatic coupling between the two sub-systems.Comment: 11 pages, 6 figure

Two Modes of Change in Southern Ocean Productivity Over the Past Million Years

Export of organic carbon from surface waters of the Antarctic Zone of the Southern Ocean decreased during the last ice age, coinciding with declining atmospheric carbon dioxide (CO2) concentrations, signaling reduced exchange of CO2 between the ocean interior and the atmosphere. In contrast, in the Subantarctic Zone, export production increased into ice ages coinciding with rising dust fluxes, thus suggesting iron fertilization of subantarctic phytoplankton. Here, a new high-resolution productivity record from the Antarctic Zone is compiled with parallel subantarctic data over the past million years. Together, they fit the view that the combination of these two modes of Southern Ocean change determines the temporal structure of the glacial-interglacial atmospheric CO2 record, including during the interval of “lukewarm” interglacials between 450 and 800 thousand years ago