Relationship of Community Characteristics to Harvest Reporting: Comparative Study of Household Surveys and Harvest Tickets in Alaska

Accurate harvest reporting is critical for wildlife management. Rural Alaskan communities reported a median of 42% of moose harvested via traditional harvest tickets compared to those reported in household surveys. This harvest-report ratio did not change over time. Twice as many moose were reported harvested during subsistence household surveys (n = 8,039) than on hunter harvest tickets (n = 3,557). Percentage of the community that was indigenous, used and shared moose, and absence of a wildlife biologist or road access were associated with low harvest-report ratios. Analysis revealed that household surveys provide important information about moose harvest rates and their use should be expanded. Reporting rates might be improved by building trust through respectful dialogue between hunters and managers and by placing more emphasis on the benefits of reporting harvests and less emphasis on enforcement.     

Status and trends of amphibian declines and extinctions worldwide

The first global assessment of amphibians provides new context for the well-publicized phenomenon of amphibian declines. Amphibians are more threatened and are declining more rapidly than either birds or mammals. Although many declines are due to habitat loss and overutilization, other, unidentified processes threaten 48% of rapidly declining species and are driving species most quickly to extinction. Declines are nonrandom in terms of species' ecological preferences, geographic ranges, and taxonomic associations and are most prevalent among Neotropical montane, stream-associated species. The lack of conservation remedies for these poorly understood declines means that hundreds of amphibian species now face extinction.     

Generating diverse skeletons of small molecules combinatorially

Lack of efficient access to collections of synthetic compounds that have skeletal diversity is a key bottleneck in the small-molecule discovery process. We report a synthesis strategy that involves transforming substrates with different appendages that pre-encode skeletal information, named sigma elements, into products that have different skeletons with the use of common reaction conditions. With this approach, split-pool synthesis can be used to pre-encode skeletal diversity combinatorially and thereby generate such small molecules very efficiently. A split-pool synthesis of more than 1000 compounds produced overlapping, combinatorial matrices of molecular skeletons and appended building blocks in both enantiomeric and diastereomeric forms.     

支持完整性决策的数据管理

大多数管道的运营、维护和其它设备管理部门,采用一系列各自独立的数据资源和应用程序来管理管道的完整性、维修和安全.将各个独立的数据整合成一个单一的、相互关联的数据管理系统可以提供很多重要的好处.然而,在给定管道早期投资的情况下,评价用于建立一个包含功能强大的数据采集程序在内的新系统的成本是非常困难的.采用静态的和独立的维护性数据的专用风险管理软件被作为一种快捷的、低成本的替代选择,以此来满足规章制度所规定的必须遵从的行业要求.通过开发传统数据等方法,以最小的启动成本来实现阶段性的完整性数据管理.     

Allosteric mechanisms of signal transduction

Forty years ago, a simple model of allosteric mechanisms (indirect interactions between distinct sites), used initially to explain feedback-inhibited enzymes, was presented by Monod, Wyman, and Changeux. We review the MWC theory and its applications for the understanding of signal transduction in biology, and also identify remaining issues that deserve theoretical and experimental substantiation.     

Molecular borromean rings

The realization of the Borromean link in a wholly synthetic molecular form is reported. The self-assembly of this link, which is topologically achiral, from 18 components by the template-directed formation of 12 imine and 30 dative bonds, associated with the coordination of three interlocked macrocycles, each tetranucleating and decadentate overall, to a total of six zinc(II) ions, is near quantitative. Three macrocycles present diagonally in pairs, six exo-bidentate bipyridyl and six endo-diiminopyridyl ligands to the six zinc(II) ions. The use, in concert, of coordination, supramolecular, and dynamic covalent chemistry allowed the highly efficient construction, by multiple cooperative self-assembly processes, of a nanoscale dodecacation with an approximate diameter of 2.5 nanometers and an inner chamber of volume 250 A(3), lined with 12 oxygen atoms.     

Ancient tripartite coevolution in the attine ant-microbe symbiosis

The symbiosis between fungus-growing ants and the fungi they cultivate for food has been shaped by 50 million years of coevolution. Phylogenetic analyses indicate that this long coevolutionary history includes a third symbiont lineage: specialized microfungal parasites of the ants' fungus gardens. At ancient levels, the phylogenies of the three symbionts are perfectly congruent, revealing that the ant-microbe symbiosis is the product of tripartite coevolution between the farming ants, their cultivars, and the garden parasites. At recent phylogenetic levels, coevolution has been punctuated by occasional host-switching by the parasite, thus intensifying continuous coadaptation between symbionts in a tripartite arms race.     

Resonant amplification of magnetic domain-wall motion by a train of current pulses

The current-induced motion of magnetic domain walls confined to nanostructures is of interest for applications in magnetoelectronic devices in which the domain wall serves as the logic gate or memory element. The injection of spin-polarized current below a threshold value through a domain wall confined to a pinning potential results in its precessional motion within the potential well. We show that by using a short train of current pulses, whose length and spacing are tuned to this precession frequency, the domain wall's oscillations can be resonantly amplified. This makes possible the motion of domain walls with much reduced currents, more than five times smaller than in the absence of resonant amplification.     

Chemical pruning of plants

The lower alkyl esters of the C(8) to C(12) fatty acids and the C(8) to C(10) fatty alcohols selectively kill or inhibit the terminal meristem without damaging the axillary meristems, foliage, or stem tissue of a wide variety of plants. The axillary meristems develop at nearly the same time as those of plants whose terminal meristems have been removed manually. The concentration of the fatty acid esters and alcohols required to kill the terminal meristem range from 0.025 to 0.05M for herbaceous plants, 0.05 to 0.16M for semi-woody plants, and 0.16 to 0.27M for woody plants.