627 research outputs found
Genetic Analysis of the Federally Endangered Winged Mapleleaf Mussel to Aid Proposed Re-introduction Efforts
The winged mapleleaf, Quadrula fragosa, historically occurred in the Mississippi, Tennessee, Ohio, and Cumberland river drainages, but has suffered severe population and range reductions. At the time that the species was federally listed as endangered, its range was thought to have been reduced to a stretch of the St. Croix River between northwestern Wisconsin and east-central Minnesota. Recently, morphologically “Q. fragosa-like” specimens were discovered at sites in Arkansas (Ouachita River and Saline River), Missouri (Bourbeuse River), and Oklahoma (Little River). Subsequently, a plan was proposed to re-introduce Q. fragosa into portions of its historic range where its been extirpated from within the upper Mississippi River basin. The project objectives were 1.) Recommend the number of “founder” individuals required to generate the same level of genetic diversity in a newly established population as seen in the original population; 2.) In addition, allow for the ability to identify newly recruited juvenile mussels using microsatellite genotyping, and link individuals from the founded population back to the St. Croix River source population
Notes and Discussion Piece: Status of the Topeka Shiner in Iowa
The Topeka shiner Notropis topeka is native to Iowa, Kansas, Minnesota, Missouri, Nebraska, and South Dakota and has been federally listed as endangered since 1998. Our goals were to determine the present distribution and qualitative status of Topeka shiners throughout its current range in Iowa and characterize the extent of decline in relation to its historic distribution. We compared the current (2016–2017) distribution to distributions portrayed in three earlier time periods. In 2016–2017 Topeka shiners were found in 12 of 20 HUC10 watersheds where they occurred historically. Their status was classified as stable in 21% of the HUC10 watersheds, possibly stable in 25%, possibly recovering in 8%, at risk in 33%, and possibly extirpated in 13% of the watersheds. The increasing trend in percent decline evident in earlier time periods reversed, going from 68% in 2010–11 to 40% in the most recent surveys. Following decades of decline, the status of Topeka shiners in Iowa appears to be improving. One potential reason for the reversal in the distributional decline of Topeka shiners in Iowa is the increasing number of oxbow restorations. Until a standardized monitoring program is established for Iowa, periodic status assessments such as this will be necessary to chronicle progress toward conserving this endangered fish species
Can Survey-based Scenarios Measure Consumer Values for Improved Food Safety?
Demand and Price Analysis, Food Consumption/Nutrition/Food Safety,
Developments in mental health service provision: views of service users and carers
This paper reports on a study in two NHS Mental Health Trusts in England in 2008-2009. Data were collected from staff, service users and carers to inform service and workforce developments. The findings reported relate to service users and carers and concur with staff views. They relate to modernisation of services, the challenges of a multiplicity of stakeholders and organisations, as well as the need to involve users and carers in developments. The findings resonate with national and local policy with a move away from traditional psychiatric care to integrated person-centred community care with a focus on recovery, rehabilitation and self care
Projective Ribbon Permutation Statistics: a Remnant of non-Abelian Braiding in Higher Dimensions
In a recent paper, Teo and Kane proposed a 3D model in which the defects
support Majorana fermion zero modes. They argued that exchanging and twisting
these defects would implement a set R of unitary transformations on the zero
mode Hilbert space which is a 'ghostly' recollection of the action of the braid
group on Ising anyons in 2D. In this paper, we find the group T_{2n} which
governs the statistics of these defects by analyzing the topology of the space
K_{2n} of configurations of 2n defects in a slowly spatially-varying gapped
free fermion Hamiltonian: T_{2n}\equiv {\pi_1}(K_{2n})$. We find that the group
T_{2n}= Z \times T^r_{2n}, where the 'ribbon permutation group' T^r_{2n} is a
mild enhancement of the permutation group S_{2n}: T^r_{2n} \equiv \Z_2 \times
E((Z_2)^{2n}\rtimes S_{2n}). Here, E((Z_2)^{2n}\rtimes S_{2n}) is the 'even
part' of (Z_2)^{2n} \rtimes S_{2n}, namely those elements for which the total
parity of the element in (Z_2)^{2n} added to the parity of the permutation is
even. Surprisingly, R is only a projective representation of T_{2n}, a
possibility proposed by Wilczek. Thus, Teo and Kane's defects realize
`Projective Ribbon Permutation Statistics', which we show to be consistent with
locality. We extend this phenomenon to other dimensions, co-dimensions, and
symmetry classes. Since it is an essential input for our calculation, we review
the topological classification of gapped free fermion systems and its relation
to Bott periodicity.Comment: Missing figures added. Fixed some typos. Added a paragraph to the
conclusio
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