751 research outputs found
Multiple differences in calling songs and other traits between solitary and gregarious Mormon crickets from allopatric mtDNA clades
The Linnaean Society, The British Ecological Society, The Russell Trust (St. Andrews), The Orthopterists' Society and an NSERC (Canada) grant to DTG. Gordon S. Brown provided assistance with digital imaging and morphological measurements.Background: In acoustic species, traits such as male calling song are likely to diverge quickly between allopatric populations due to sexual selection, and divergence in parameters such as carrier frequency, chirp structure, and other important song characters can influence sexual isolation. Here we make use of two forms of Mormon crickets to examine differences in a broad suite of traits that have the potential to influence speciation via sexual isolation. Mormon crickets in "gregarious" populations aggregate into dense migratory bands, and females are the sexually competitive Fsex ( sex- role reversal). There is also a non-outbreak "solitary" form. These two forms are largely but not perfectly correlated with a significant mtDNA subdivision within the species that is thought to have arisen in allopatry. Combined information about multiple, independently evolving traits, such as morphology and structural and behavioural differences in calling song, provides greater resolution of the overall differences between these allopatric populations, and allows us to assess their stage of divergence. We test two predictions, first that the forms differ in song and second that gregarious males are more reluctant to sing than solitary males due to sex role reversal. We also tested for a difference in the relationship between the size of the forewing resonator, the mirror, and carrier frequency, as most models of sound production in crickets indicate that mirror size should predict carrier frequency. Results: Multivariate analyses showed that solitary and gregarious individuals from different populations representing the two mtDNA clades had almost non-overlapping distributions based on multiple song and morphological measurements. Carrier frequency differed between the two, and gregarious males were more reluctant to sing overall. Mirror size predicted carrier frequency; however, the relationship between mirror size and surface area varied between solitary and gregarious forms, suggesting that factors above and beyond mirror size contribute to carrier frequency. Conclusion: The two clades of Mormon crickets differ in a broad suite of independent traits that probably justify subspecies status ( the two can successfully mate so may not be reproductively isolated). However, our results emphasize the importance of carefully distinguishing the ultimate causation of differences between traits used to delineate species or subspecies boundaries.Publisher PDFPeer reviewe
Multiple differences in calling songs and other traits between solitary and gregarious Mormon crickets from allopatric mtDNA clades
BACKGROUND: In acoustic species, traits such as male calling song are likely to diverge quickly between allopatric populations due to sexual selection, and divergence in parameters such as carrier frequency, chirp structure, and other important song characters can influence sexual isolation. Here we make use of two forms of Mormon crickets to examine differences in a broad suite of traits that have the potential to influence speciation via sexual isolation. Mormon crickets in "gregarious" populations aggregate into dense migratory bands, and females are the sexually competitive sex (sex-role reversal). There is also a non-outbreak "solitary" form. These two forms are largely but not perfectly correlated with a significant mtDNA subdivision within the species that is thought to have arisen in allopatry. Combined information about multiple, independently evolving traits, such as morphology and structural and behavioural differences in calling song, provides greater resolution of the overall differences between these allopatric populations, and allows us to assess their stage of divergence. We test two predictions, first that the forms differ in song and second that gregarious males are more reluctant to sing than solitary males due to sex role reversal. We also tested for a difference in the relationship between the size of the forewing resonator, the mirror, and carrier frequency, as most models of sound production in crickets indicate that mirror size should predict carrier frequency. RESULTS: Multivariate analyses showed that solitary and gregarious individuals from different populations representing the two mtDNA clades had almost non-overlapping distributions based on multiple song and morphological measurements. Carrier frequency differed between the two, and gregarious males were more reluctant to sing overall. Mirror size predicted carrier frequency; however, the relationship between mirror size and surface area varied between solitary and gregarious forms, suggesting that factors above and beyond mirror size contribute to carrier frequency. CONCLUSION: The two clades of Mormon crickets differ in a broad suite of independent traits that probably justify subspecies status (the two can successfully mate so may not be reproductively isolated). However, our results emphasize the importance of carefully distinguishing the ultimate causation of differences between traits used to delineate species or subspecies boundaries
Oportunidades agroindustriales en la Cuenca del PacÃfico
Compares the possibilities of New Zealand and Peru in export agriculture and agribusiness, in which both countries have great potential. He considers that, to remain competitive internationally, both countries must stop exporting raw materials and replace them with products with higher added value. It analyzes the situation and the expected evolution of four New Zealand export products: meat, milk and derivatives, venison and kiwi, and argues that the central aspect to take advantage of the challenges and opportunities in agribusiness is to never forget the importance of the consumer and the consumption patterns, as the importance given to products sensitive to the environment is growing. As possible strategies, mention is made of taking advantage of the comparative advantages offered by nature, developing products specifically destined for the export market, protecting natural resources while maintaining the international competitiveness of agribusiness.Compara las posibilidades de Nueva Zelanda y Perú en agricultura exportadora y agronegocios, en los que ambos paÃses tienen gran potencial. Considera que, para seguir siendo competitivos a nivel internacional, ambos paÃses deben dejar de exportar materias primas y sustituirlas por productos de mayor valor añadido. Analiza la situación y la evolución esperada de cuatro productos de exportación de Nueva Zelanda: carne, leche y derivados, venado y kiwi, y sostiene que el aspecto central para aprovechar los desafÃos y oportunidades del agronegocio es no olvidar nunca la importancia del consumidor. y los patrones de consumo, ya que crece la importancia otorgada a los productos sensibles al medio ambiente. Como posibles estrategias se menciona aprovechar las ventajas comparativas que ofrece la naturaleza, desarrollar productos destinados especÃficamente al mercado de exportación, proteger los recursos naturales manteniendo la competitividad internacional de los agronegocios
Polarization Measurements of the Polluted White Dwarf G29-38
We have made high-precision polarimetric observations of the polluted white dwarf G29-38 with the HIgh Precision Polarimetric Instrument 2. The observations were made at two different observatories – using the 8.1-m Gemini North Telescope and the 3.9-m Anglo-Australian Telescope – and are consistent with each other. After allowing for a small amount of interstellar polarization, the intrinsic linear polarization of the system is found to be 275.3 ± 31.9 parts per million at a position angle of 90.8 ± 3.8◦ in the SDSS g
band. We compare the observed polarization with the predictions of circumstellar disc models. The measured polarization is small in the context of the models we develop, which only allows us to place limits on disc inclination and Bond albedo for optically thin disc geometries. In this case, either the inclination is near-face-on or the albedo is small – likely in the range 0.05–0.15 – which is in line with other debris disc measurements. A preliminary search for the effects of G29-38’s pulsations in the polarization signal produced inconsistent results. This may be caused by beating effects, indicate a clumpy dust distribution, or be a consequence of measurement systematics
Barite encrustation of benthic sulfur-oxidizing bacteria at a marine cold seep
Crusts and chimneys composed of authigenic barite are found at methane seeps and hydrothermal vents that expel fluids rich in barium. Microbial processes have not previously been associated with barite precipitation in marine cold seep settings. Here, we report on the precipitation of barite on filaments of sulfide-oxidizing bacteria at a brine seep in the Gulf of Mexico. Barite-mineralized bacterial filaments in the interiors of authigenic barite crusts resemble filamentous sulfide-oxidizing bacteria of the genus Beggiatoa. Clone library and iTag amplicon sequencing of the 16S rRNA gene show that the barite crusts that host these filaments also preserve DNA of Candidatus Maribeggiatoa, as well as sulfate-reducing bacteria. Isotopic analyses show that the sulfur and oxygen isotope compositions of barite have lower δ34S and δ18O values than many other marine barite crusts, which is consistent with barite precipitation in an environment in which sulfide oxidation was occurring. Laboratory experiments employing isolates of sulfide-oxidizing bacteria from Gulf of Mexico seep sediments showed that under low sulfate conditions, such as those encountered in brine fluids, sulfate generated by sulfide-oxidizing bacteria fosters rapid barite precipitation localized on cell biomass, leading to the encrustation of bacteria in a manner reminiscent of our observations of barite-mineralized Beggiatoa in the Gulf of Mexico. The precipitation of barite directly on filaments of sulfide-oxidizing bacteria, and not on other benthic substrates, suggests that sulfide oxidation plays a role in barite formation at certain marine brine seeps where sulfide is oxidized to sulfate in contact with barium-rich fluids, either prior to, or during, the mixing of those fluids with sulfate-containing seawater in the vicinity of the sediment/water interface. As with many other geochemical interfaces that foster mineral precipitation, both biological and abiological processes likely contribute to the precipitation of barite at marine brine seeps such as the one studied here
Polarization measurements of the polluted white dwarf G29-38
We have made high precision polarimetric observations of the polluted white
dwarf G29-38 with the HIgh Precision Polarimetric Instrument 2. The
observations were made at two different observatories -- using the 8.1-m Gemini
North Telescope and the 3.9-m Anglo AustralianTelescope -- and are consistent
with each other. After allowing for a small amount of interstellar
polarization, the intrinsic linear polarization of the system is found to be
275.3 +/- 31.9 parts-per-million at a position angle of 90.8 +/- 3.8 degrees in
the SDSS g' band. We compare the observed polarization with the predictions of
circumstellar disc models. The measured polarization is small in the context of
the models we develop which only allows us to place limits on disc inclination
and Bond albedo for optically thin disc geometries. In this case either the
inclination is near face-on or the albedo is small -- likely in the range 0.05
to 0.15 -- which is in line with other debris disc measurements. A preliminary
search for the effects of G29-38's pulsations in the polarization signal
produced inconsistent results. This may be caused by beating effects, indicate
a clumpy dust distribution, or be a consequence of measurement systematics.Comment: 15 pages, 6 figures, 4 tables. Accepted to MNRA
Inhibition of Integrin α\u3csub\u3ed\u3c/sub\u3eβ\u3csub\u3e2\u3c/sub\u3e-Mediated Macrophage Adhesion to End Product of Docosahexaenoic Acid (DHA) Oxidation Prevents Macrophage Accumulation During Inflammation
A critical step in the development of chronic inflammatory diseases is the accumulation of proinflammatory macrophages in the extracellular matrix (ECM) of peripheral tissues. The adhesion receptor integrin αDβ2 promotes the development of atherosclerosis and diabetes by supporting macrophage retention in inflamed tissue. We recently found that the end product of docosahexaenoic acid (DHA) oxidation, 2-(ω-carboxyethyl)- pyrrole (CEP), serves as a ligand forαDβ2.CEPadduct withECM is generated during inflammation-mediated lipid peroxidation. The goal of this project was to identify a specific inhibitor for αDβ2-CEP interaction that can prevent macrophage accumulation. Using a specially designed peptide library, Biacore-detected protein-protein interaction, and adhesion of integrin-transfected HEK 293 cells, we identified a sequence (called P5 peptide) that significantly and specifically inhibited αD-CEP binding. In the model of thioglycollate-induced peritoneal inflammation, the injection of cyclic P5 peptide reduced 3-fold the macrophage accumulation in WT mice but had no effect in αD-deficient mice. The tracking of adoptively transferred, fluorescently labeled WT and αD-/- monocytes in the model of peritoneal inflammation and in vitro two-dimensional and three-dimensional migration assays demonstrated thatP5peptide does not affectmonocytetransendothelial migration or macrophage efflux from the peritoneal cavity but regulates macrophage migration through the ECM. Moreover, the injection ofP5peptide intoWTmiceona high-fat diet prevents macrophage accumulation in adipose tissue in anαDβ2-dependent manner.Takentogether, these resultsdemonstratetheimportance of αDβ2-mediated macrophage adhesion for the accumulation of infiltrating macrophages in the inflamed ECM and propose P5 peptide as a potential inhibitor of atherogenesis and diabetes
Advanced Colloids Experiment (Temperature Controlled) - ACE-T6
Increment 53 - 54 Science Symposium presentation of Advanced Colloids Experiment (ACE-T6) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators
Recommended from our members
Sandia National Laboratories/New Mexico Environmental Information Document - Volume 1
This Sandia National Laboratories/New Mexico Environmental Information Document (EID) compiles information on the existing environment, or environmental baseline, for SNUNM. Much of the information is drawn from existing reports and databases supplemented by new research and data. The SNL/NM EID, together with the Sandia National Laboratories/New Mexico Facilities and Safety Information Document, provide a basis for assessing the environment, safety, and health aspects of operating selected facilities at SNL/NM. The environmental baseline provides a record of the existing physical, biological, and socioeconomic environment at SNL/NLM prior to being altered (beneficially or adversely) by proposed programs or projects. More specifically, the EID provides information on the following topics: Geology; Land Use; Hydrology and Water Resources; Air Quality and Meteorology; Ecology; Noise and Vibration; Cultural Resources; Visual Resources; Socioeconomic and Community Services; Transportation; Material Management; Waste Management; and Regulatory Requirements
- …