Evolution and Biogeography of Haemonchus contortus: Linking Faunal Dynamics in Space and Time

History is the foundation that informs about the nuances of faunal assembly that are essential in understanding the dynamic nature of the host-parasite interface. All of our knowledge begins and ends with evolution, ecology and biogeography, as these interacting facets determine the history of biodiverse systems. These components, relating to Haemonchus, can inform about the complex history of geographical distribution, host association and the intricacies of host-parasite associations that are played out in physiological and behavioural processes that influence the potential for disease and our capacity for effective control in a rapidly changing world. Origins and evolutionary diversification among species of the genus Haemonchus and Hae- monchus contortus occurred in a complex crucible defined by shifts in environmental structure emerging from cycles of climate change and ecological perturbation during the late Tertiary and through the Quaternary. A history of sequential host colonization associated with waves of dispersal bringing assemblages of ungulates from Eurasia into Africa and processes emerging from ecosystems in collision and faunal turnover defined the arena for radiation among 12 recognized species of Haemonchus. Among congeners, the host range for H. contortus is exceptionally broad, including species among artiodactyls of 40 genera representing 5 families (and within 12 tribes of Bovi- dae). Broad host range is dramatically reflected in the degree to which translocation, introduction and invasion with host switching, has characterized an expanding distribution over time in North America, South America, southern Eurasia, Australia and New Zealand, coincidental with agriculture, husbandry and global colonization by human populations driven particularly by European exploration after the 1500s. African origins in xeric to mesic habitats of the African savannah suggest that historical constraints linked to ecological adaptations (tolerances and developmental thresholds defined by temperature and humidity for larval stages) will be substantial determinants in the potential outcomes for widespread geographical and host colonization which are predicted to unfold over the coming century. Insights about deeper evolutionary events, ecology and biogeography are critical as understanding history informs us about the possible range of responses in complex systems under new regimes of environmental forcing, especially, in this case, ecological perturbation linked to climate change. A deeper history of perturbation is relevant in understanding contemporary systems that are now strongly structured by events of invasion and colonization. The relaxation of abiotic and biotic controls on the occurrence of H. contortus, coincidental with inception and dissemination of anthelmintic resistance may be synergistic, serving to exacerbate challenges to control parasites or to limit the socioeconomic impacts of infection that can influence food security and availability. Studies of haemonchine nematodes contribute directly to an expanding model about the nature of diversity and the evolutionary trajectories for faunal assembly among complex hosteparasite systems across considerable spatial and temporal scales

Science, Politics, and U.S. Forest Law: The Battle over the Forest Service Planning Rule

This paper reviews the battles over the Forest Service planning rule that culminated in the November 2000 revising of the regulations implementing the National Forest Management Act. In a departure froj the agency’s emphasis on multiple use, the rule established ecological sustainability as the key objective guiding planning for the national forests. The supporting material explicitly states that “it is based on the recommendation of an eminent committee of scientists.” This pape5r examines the Committee of Scientists and the NFMA rule as a case study in the relation between science and politics in the development and implementation of statutory standards for management of the National Forest System. The conclusion considerations the broader question of whether the Committee and Forest Service overstepped their appropriate roles in promoting what is essentially a new statutory mandate.Forest Service, planning, National Forest Management Act, Committee of Scientists, multiple use, sustainability

Insights about Diversity of Tetrabothriidae (Eucestoda) among Holarctic Alcidae (Charadriiformes): What Is \u3ci\u3eTetrabothrius jagerskioeldi\u3c/i\u3e?

Tetrabothriid cestodes are characteristic helminths that infect species of seabirds globally. We begin with the exploration of the diversity of tapeworms of the genus Tetrabothrius Rudolphi, 1819 (Eucestoda: Tetrabothriidae), some of which are distributed among seabirds of the family Alcidae (Charadriiformes) at boreal to higher latitudes of Holarctic seas. During the course of 2 decades of field inventory from 1975 through the early 1990s (in addition to earlier collections assembled by Robert L. Rausch and colleagues in Alaska initiated in the late 1940s), an extensive series of tapeworm specimens attributable to species of Tetrabothrius was recovered from seabirds across the North Pacific Basin. It was assumed based on published records of species richness in this fauna that a single species, Tetrabothrius jagerskioeldi Nybelin, 1916, would predominate among alcid hosts. In contrast, detailed study revealed considerable morphological complexity that could not be accommodated within a single species. Further, it was apparent that the limits for the primary morphological attributes of T. jagerskioeldi were not clearly defined. We redescribe T. jagerskioeldi based on direct examination of the type series of specimens from Sweden and an assemblage of specimens largely from alcid hosts from the North Pacific basin. Specimens of T. jagerskioeldi are diagnosed by a characteristic configuration of the genital atrium, position of the male and female genital canals, structure of the male and female organ systems, and numbers of testes. Based on the spectrum of characters we explored, it was apparent that numerous specimens of Tetrabothrius among genera and species of Alcidae from the North Pacific inventory could not be accommodated in T. jagerskioeldi and provisionally are referred to Tetrabothrius undescribed n. sp. pending ongoing evaluations. Superficially, these are all large and robust tapeworms referable to Tetrabothrius, potentially contributing to misidentifications and misattribution that have occurred both in the literature and in the few archived specimens in museums. We summarize the results of extensive inventory collections since 1950, establishing a distributional baseline for species of Tetrabothrius from a wide range of geographic localities and an assemblage of host species among the Alcidae and some species of Laridae, Stercorariidae, and Phalacrocoracidae. We further evaluate the validity of historical published records for T. jagerskioeldi and other congeners among alcids and other seabirds. A conclusion that emerges is that T. jagerskioeldi is a rare tapeworm with a patchy distribution in pelagic to nearshore marine environments, showing considerable heterogeneity in space and time, among alcid seabirds across high-latitude seas of the Holarctic. Prior concepts for host range require reevaluation. We demonstrate that the associations for T. jagerskioeldi are relatively narrow and appear to involve a more limited spectrum of alcid hosts, and less often other species of marine birds, than currently assumed. A robust understanding of parasite species diversity and distribution is critical in establishing baselines across marine ecosystems. Our current study among species of Tetrabothrius, especially in the North Pacific basin and Bering Sea ecosystem contributes to development of a series of specimen-centered baselines derived primarily from the late 1970s to the early 1980s against which accelerating perturbations linked to climate warming and ocean-atmosphere interactions may be explored. Detailed knowledge of specimen-based faunal diversity for parasites provides a cumulative, temporal, and spatial snapshot and proxy for conditions in marine foodwebs and the continuity of trophic linkages

Protecting the Axion with Local Baryon Number

The Peccei-Quinn (PQ) solution to the Strong CP Problem is expected to fail unless the global symmetry U(1)${}_{\rm PQ}$ is protected from Planck-scale operators up to high mass dimension. Suitable protection can be achieved if the PQ symmetry is an automatic consequence of some gauge symmetry. We highlight that if baryon number is promoted to a gauge symmetry, the exotic fermions needed for anomaly cancellation can elegantly provide an implementation of the Kim-Shifman-Vainshtein-Zakharov 'hidden axion' mechanism with a PQ symmetry protected from Planck-scale physics.Comment: 5 pages; v2: models improved, references adde

Dilaton domination in the MSSM and its singlet extensions

We analyse the current status of the dilaton domination scenario in the MSSM and its singlet extensions taking into account the measured value of the Higgs mass, the relic abundance of dark matter and constraints from SUSY searches at the LHC. We find that in the case of the MSSM the requirement of a dark matter relic abundance in accord with observation severely restricts the allowed parameter space, implying an upper bound on the superpartner masses which makes it fully testable at LHC-14. In singlet extensions with a large singlet-MSSM coupling $\lambda$ as favoured by naturalness arguments the coloured sparticles should again be within the reach of the LHC-14, while for small $\lambda$ it is possible to decouple the MSSM and singlet sectors, achieving the correct dark matter abundance with a singlino LSP while allowing for a heavy MSSM spectrum.Comment: 9 pages, 3 figure

Conglomerate Industry Choice and Product Differentiation

We use text-based computational analysis of business descriptions from 10-Ks to examine in which industries conglomerates are most likely to operate and to understand conglomerate valuations. We find that conglomerates are more likely to operate in industry pairs that are closer together in the product space and in industry pairs that have profitable opportunities "between" them. Conglomerate firms have lower stock market valuations than matched single-segment firms when their products are easier to replicate with single-segment firms. Conglomerate firms have stock market premiums when they have higher product differentiation and produce in more profitable industries. These findings are consistent with successful conglomerate firms having higher product differentiation and lower cost entry into profitable markets when operating in strategically chosen industry pairs.

Integrating genomics and phylogenetics in understanding the history of Trichinella species

In 2004, funding was received by Washington University’s Genome Sequencing Center through NHGRI, to completely sequence several nematode genomes as part of a holistic effort to advance our understanding of the human genome and evolution within the Metazoa. Trichinella spiralis was among this group of worms because of its strategic location at the base of the phylum Nematoda, and the belief that extant species represented an ancient divergent event that occurred as early as the Paleozoic. At the same time, a concerted effort was put forth to solidify the phylogeny of extant species of Trichinella based upon molecular analyses of a multi-gene system to understand the history of the genus and thereby enhance utilization of the forthcoming sequence data. Since the inception of this research, several findings have emerged: (1) the size of T. spiralis genome estimated by flow cytometry (71.3 Mb) is substantially smaller than originally predicted (270 Mb); (2) to date, a subset of the total of 3,534,683 sequences have been assembled into a 59.3 Mb unique sequence; (3) 19% of the assembled sequence is comprised of repetitive elements; and (4) sequence data are predicated upon extant T. spiralis which probably diverged as little as 20 million years ago. Thus, the utility of the T. spiralis genome as representative of an archaic species must be tempered with the knowledge that encapsulated and non-encapsulated clades probably separated during the mid-Miocene as temperate ecosystems changed

Self-interacting dark matter with a stable vector mediator

Light vector mediators can naturally induce velocity-dependent dark matter self-interactions while at the same time allowing for the correct dark matter relic abundance via thermal freeze-out. If these mediators subsequently decay into Standard Model states such as electrons or photons however, this is robustly excluded by constraints from the Cosmic Microwave Background. We study to what extent this conclusion can be circumvented if the vector mediator is stable and hence contributes to the dark matter density while annihilating into lighter degrees of freedom. We find viable parts of parameter space which lead to the desired self-interaction cross section of dark matter to address the small-scale problems of the collisionless cold dark matter paradigm while being compatible with bounds from the Cosmic Microwave Background and Big Bang Nucleosynthesis observations.Comment: 25 pages, 6 figures. Matches published versio