126 research outputs found

    CHARACTERIZING FORAGING PATTERNS AMONG CATTLE AND BONDED AND NON-BONDED SMALL RUMINANTS USING SPATIAL POINT PROCESS TECHNIQUES

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    This paper uses the technique of spatial point processes to describe the spatial patterns of freeranging cattle and small ruminants. Two mixed-species livestock groups were monitored while foraging on 410 ha of brush-infested Southern New Mexico rangeland during July and August 1988. The groups consisted of crossbred Bos taurus and Bos indicus beef cattle with white-faced sheep (Ovis aries) and mohair goats (Capra hircus). The bonded group consisted of small ruminants that had their behaviours modified through socialization with cattle to form a ‘flerd’ in which small ruminants consistently remained near cattle. Small ruminants in the non-bonded group had not been socialized with cattle. A subset of animal location data measured during the morning and afternoon over five days for both the bonded and non-bonded groups was analyzed for spatial patterns. Only data for five morning periods (7:00-8:00 a.m.) are reported because morning and afternoon spatial patterns were similar. Observed nearest neighbor distances, mean number of small ruminant near an arbitrary cow, and point-to-animal distances were compared to Monte Carlo simulations of independently and uniformly distributed animal locations. Bonded and non-bonded groups were also compared. Results suggested bonded and non-bonded groups were similar in spatial patterns of intra-specific distances for both cattle and small ruminants. However, bonding changed the repulsive relationship observed between cattle and non-bonded small ruminants stocked together to one of inter-specific attraction. Bonded small ruminants remained close to and formed inter-specific clusters with cattle. In addition, the mean number of bonded small ruminants near an arbitrary cow was consistently higher than for non-bonded small ruminants. Finally, the spatial pattern of cattle across the paddock did not differ between bonded and non-bonded groups, while bonded small ruminants tended to disperse slightly more uniformly across the paddock than did non-bonded small ruminants. These findings indicate the usefulness of spatial point processes techniques to analyze such animal location data, substantiate on a larger scale conclusions of previous, replicated studies about the effect of bonding small ruminants to cattle, and suggest utilization of paddock landscapes may be positively influenced using flerds compared to flocks and herds

    Advances in the use of biological stabilisers and hyper-compaction for sustainable earthen construction materials.

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    In the majority of cases, earthen construction materials for real buildings require amendment to deliver suitable material properties, which could be some additional strength or resilience to erosion. In modern earthen construction, in India, Australia and other parts of the world, cement and lime have been successfully used as stabilisers, providing both strength and durability benefits. However, the use of cement is detrimental to the green credentials of earthen construction materials, due to the large carbon footprint of that material’s manufacture and, for some time, researchers have been motivated to find more appropriate stabilisers and manufacturing methods. In this paper, we present recent findings from two projects that are linked by this motivation, and involve the study of bio-based stabilisers and alternative manufacturing methods for insitu and unit-based materials. Results are presented from laboratory testing of strength and durability of a range of materials, bio-stabilisers and manufacturing processes, indicating that there could be viable alternatives to cement and lime, certainly for many current uses of earthen construction materials

    Fluctuation Study of the Specific Heat of MgB2

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    The specific heat of polycrystalline Mg11^{11}B2_{2} has been measured with high resolution ac calorimetry from 5 to 45 K at constant magnetic fields. The excess specific heat above Tc_{c} is discussed in terms of Gaussian fluctuations and suggests that Mg11^{11}B2_{2} is a bulk superconductor with Ginzburg-Landau coherence length ξ0=26\xi_{0}=26 \AA . The transition-width broadening in field is treated in terms of lowest-Landau-level (LLL) fluctuations. That analysis requires that ξ0=20\xi_{0}=20 \AA . The underestimate of the coherence length in field, along with deviations from 3D LLL predictions, suggest that there is an influence from the anisotropy of Bc2_{c2} between the c-axis and the a-b plane.Comment: Phys. Rev. B 66, 134515 (2002

    Consequences of infanticide for a gregarious ectoparasitoid of leafroller larvae

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    1. In this laboratory study, the clutch size and handling time of Goniozus jacintae were investigated, a comparison of its life-history performance between primary and secondary (laid after infanticide events) broods was carried out, and the lipid and protein concentrations in the haemolymph of non-parasitised and parasitised hosts were estimated. 2. It was found that G. jacintae temporarily paralysed its host larvae for 66 min and briefly guarded its brood for 66 min. The clutch size of G. jacintae increased from two to seven with increasing larval fresh weight of its host, and both ovicide and larvicide of primary clutches occurred in 81% of encounters. 3. Secondary clutches of G. jacintae were significantly larger than primary clutches in two of three ovicide treatments for the same host individuals. Secondary clutches also experienced greater brood survivorship than primary clutches. 4. Lipid concentrations were consistently higher in the haemolymph of parasitised hosts, and protein concentrations were initially higher (until egg hatch), but increased at a lower rate in parasitised hosts than in non-parasitised hosts. 5. This study is the first to provide evidence that improved nutritional quality could be an important benefit of infanticide for an insect parasitoid, allowing for larger clutch size and improved brood survivorship among secondary broods

    Pneumolysin Activates the NLRP3 Inflammasome and Promotes Proinflammatory Cytokines Independently of TLR4

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    Pneumolysin (PLY) is a key Streptococcus pneumoniae virulence factor and potential candidate for inclusion in pneumococcal subunit vaccines. Dendritic cells (DC) play a key role in the initiation and instruction of adaptive immunity, but the effects of PLY on DC have not been widely investigated. Endotoxin-free PLY enhanced costimulatory molecule expression on DC but did not induce cytokine secretion. These effects have functional significance as adoptive transfer of DC exposed to PLY and antigen resulted in stronger antigen-specific T cell proliferation than transfer of DC exposed to antigen alone. PLY synergized with TLR agonists to enhance secretion of the proinflammatory cytokines IL-12, IL-23, IL-6, IL-1β, IL-1α and TNF-α by DC and enhanced cytokines including IL-17A and IFN-γ by splenocytes. PLY-induced DC maturation and cytokine secretion by DC and splenocytes was TLR4-independent. Both IL-17A and IFN-γ are required for protective immunity to pneumococcal infection and intranasal infection of mice with PLY-deficient pneumococci induced significantly less IFN-γ and IL-17A in the lungs compared to infection with wild-type bacteria. IL-1β plays a key role in promoting IL-17A and was previously shown to mediate protection against pneumococcal infection. The enhancement of IL-1β secretion by whole live S. pneumoniae and by PLY in DC required NLRP3, identifying PLY as a novel NLRP3 inflammasome activator. Furthermore, NLRP3 was required for protective immunity against respiratory infection with S. pneumoniae. These results add significantly to our understanding of the interactions between PLY and the immune system

    Toward osteogenic differentiation of marrow stromal cells and in vitro production of mineralized extracellular matrix onto natural scaffolds

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    Uncorrected proofTissue engineering has emerged as a new interdisciplinary field for the repair of various tissues, restoring their functions by using scaffolds, cells, and/or bioactive factors. A temporary scaffold acts as an extracellular matrix analog to culture cells and guide the development of new tissue. In this chapter, we discuss the preparation of naturally derived scaffolds of polysaccharide origin, the osteogenic differentiation of mesenchymal stem cells cultured on biomimetic calcium phosphate coatings, and the delivery of biomolecules associated with extracellular matrix mineralization

    The venom composition of the parasitic wasp Chelonus inanitus resolved by combined expressed sequence tags analysis and proteomic approach

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    <p>Abstract</p> <p>Background</p> <p>Parasitic wasps constitute one of the largest group of venomous animals. Although some physiological effects of their venoms are well documented, relatively little is known at the molecular level on the protein composition of these secretions. To identify the majority of the venom proteins of the endoparasitoid wasp <it>Chelonus inanitus </it>(Hymenoptera: Braconidae), we have randomly sequenced 2111 expressed sequence tags (ESTs) from a cDNA library of venom gland. In parallel, proteins from pure venom were separated by gel electrophoresis and individually submitted to a nano-LC-MS/MS analysis allowing comparison of peptides and ESTs sequences.</p> <p>Results</p> <p>About 60% of sequenced ESTs encoded proteins whose presence in venom was attested by mass spectrometry. Most of the remaining ESTs corresponded to gene products likely involved in the transcriptional and translational machinery of venom gland cells. In addition, a small number of transcripts were found to encode proteins that share sequence similarity with well-known venom constituents of social hymenopteran species, such as hyaluronidase-like proteins and an Allergen-5 protein.</p> <p>An overall number of 29 venom proteins could be identified through the combination of ESTs sequencing and proteomic analyses. The most highly redundant set of ESTs encoded a protein that shared sequence similarity with a venom protein of unknown function potentially specific of the <it>Chelonus </it>lineage. Venom components specific to <it>C. inanitus </it>included a C-type lectin domain containing protein, a chemosensory protein-like protein, a protein related to yellow-e3 and ten new proteins which shared no significant sequence similarity with known sequences. In addition, several venom proteins potentially able to interact with chitin were also identified including a chitinase, an imaginal disc growth factor-like protein and two putative mucin-like peritrophins.</p> <p>Conclusions</p> <p>The use of the combined approaches has allowed to discriminate between cellular and truly venom proteins. The venom of <it>C. inanitus </it>appears as a mixture of conserved venom components and of potentially lineage-specific proteins. These new molecular data enrich our knowledge on parasitoid venoms and more generally, might contribute to a better understanding of the evolution and functional diversity of venom proteins within Hymenoptera.</p
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