823 research outputs found

    Synchronous seasonal change in fin whale song in the North Pacific.

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    Fin whale (Balaenoptera physalus) song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus) and humpback whales (Megaptera novaeangliae), these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here

    The ecological distribution of monitor lizards (Reptilia, Varanidaej in Nigeria

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    The ecological distribulion of three varanid lizards (Varanus exanthematicus, K niloticus niloticus, and V. niloticus ornatusj in Nigeria is studied in the present paper, from both literature records and long-term field ecological research. V. exanthematicus is present only in central and northern Nigeria, where it seerns to be widespread and locally cornrnon in the Guinea savanna vegetation zone, but rnay be found in several spots in the Sudan savanna and even in the Sahel savanna. V. n. ornatus is confined to the extreme south of the country, ¡.e. in the coastal mangrove and deltaic swamp rainforest habita%, and also in the moist lowland rainforest. The distribution of V. n. niloticus remains controversial. It is widespread in the Sudan savanna and in the Guinea savanna, but appears only rarely in the derived savanna and rnoist lowland forest vegetation zones. Despite a few old literature records, it seerns to be absent frorn the rainforest blocks of southern Nigeria. Annual precipitation regimes seem to condition greatly the general distribution patterns of the Nigerian varanids, which are quite generalist in terms of habitat preferences within each rnajor climatic-vegetation zone. Key words: Varanidae, Distribution, Ecology, Nigeria.The ecological distribulion of three varanid lizards (Varanus exanthematicus, K niloticus niloticus, and V. niloticus ornatusj in Nigeria is studied in the present paper, from both literature records and long-term field ecological research. V. exanthematicus is present only in central and northern Nigeria, where it seerns to be widespread and locally cornrnon in the Guinea savanna vegetation zone, but rnay be found in several spots in the Sudan savanna and even in the Sahel savanna. V. n. ornatus is confined to the extreme south of the country, ¡.e. in the coastal mangrove and deltaic swamp rainforest habita%, and also in the moist lowland rainforest. The distribution of V. n. niloticus remains controversial. It is widespread in the Sudan savanna and in the Guinea savanna, but appears only rarely in the derived savanna and rnoist lowland forest vegetation zones. Despite a few old literature records, it seerns to be absent frorn the rainforest blocks of southern Nigeria. Annual precipitation regimes seem to condition greatly the general distribution patterns of the Nigerian varanids, which are quite generalist in terms of habitat preferences within each rnajor climatic-vegetation zone. Key words: Varanidae, Distribution, Ecology, Nigeria.The ecological distribulion of three varanid lizards (Varanus exanthematicus, K niloticus niloticus, and V. niloticus ornatusj in Nigeria is studied in the present paper, from both literature records and long-term field ecological research. V. exanthematicus is present only in central and northern Nigeria, where it seerns to be widespread and locally cornrnon in the Guinea savanna vegetation zone, but rnay be found in several spots in the Sudan savanna and even in the Sahel savanna. V. n. ornatus is confined to the extreme south of the country, ¡.e. in the coastal mangrove and deltaic swamp rainforest habita%, and also in the moist lowland rainforest. The distribution of V. n. niloticus remains controversial. It is widespread in the Sudan savanna and in the Guinea savanna, but appears only rarely in the derived savanna and rnoist lowland forest vegetation zones. Despite a few old literature records, it seerns to be absent frorn the rainforest blocks of southern Nigeria. Annual precipitation regimes seem to condition greatly the general distribution patterns of the Nigerian varanids, which are quite generalist in terms of habitat preferences within each rnajor climatic-vegetation zone. Key words: Varanidae, Distribution, Ecology, Nigeria

    The Structure Of The Accretion Disk In The ADC Source 4U 1822-371

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    The low-mass X-ray binary (LMXB) 4U 1822-371 has an accretion disk corona (ADC) that scatters X-ray photons from the inner disk and neutron star out of the line of sight. It has a high orbital inclination and the secondary star eclipses the disk and ADC. We have obtained new time-resolved UV spectrograms and V- and I-band photometry of 4U 1822-371. The large quadratic term in our new optical eclipse ephemeris confirms that the system has an extremely high rate of mass transfer and mass accretion. The C IV lambda lambda = 1548 - 1550 angstrom emission line has a half width of similar to 4400 km/s, indicating a strong, high velocity wind is being driven off the accretion disk. Near the disk the wind is optically thick in UV, V, and J and the eclipse analysis shows that in V and J the optically thick wind extends nearly to the outer edge of the disk. The ADC must also extend vertically to a height equal to approximately half the disk radius.Astronom

    Membrane Electrostatic Precipitator

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    A membrane is used as a collection substrate in an electrostatic precipitator (ESP). Possible material choices include fibers in the form of woven mats, screens made from stainless steel wires or fiber reinforced polymer composite membranes. The membranes have a tensile bias applied during operation, and have impulse tensile force applied during a dust removal step. By combining a dry ESP membrane field with wet-film cleaning field, it may be possible to improve collection efficiencies both by reducing turbulence and eliminating re-entrainment losses due to rapping. Through implementation of new materials that resist hostile ESP environments, the invention enhances the possibility of using novel technologies, such as pulsed corona and others, suitable for removal of molecules such as NOx and SOx, which is very important for meeting proposed PM2.5 EPA emissions regulations

    Membrane Laminar Wet Electrostatic Precipitator

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    A laminar flow, wet electrostatic precipitator (ESP) with planar collecting electrodes preferably made of membranes, such as a woven silica fiber. The collecting electrodes are spaced close to planar discharge electrodes to promote laminar flow (Re\u3c2300). Charging electrodes are positioned upstream of the wet ESP to charge the particulate entering the wet ESP to promote collection. The wet ESP is preferably downstream from a conventional turbulent dry ESP for collecting a substantial portion of the larger particulate in the gas stream prior to the gas stream entering the wet ESP

    Implications of X-Ray Line Variations for 4U1822-371

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    4U 1822-371 is one of the proto-type accretion disk coronal sources with an orbital period of about 5.6 hours. The binary is viewed almost edge-on at a high inclination angle of 83 degrees, which makes it a unique candidate to study binary orbital and accretion disk dynamics in high powered X-ray sources. We observed the X-ray source in 4U 1822-371 with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for almost nine binary orbits. X-ray eclipse times provide an update of the orbital ephemeris. We find that our result follows the quadratic function implied by previous observations; however, it suggests a flatter trend. Detailed line dynamics also confirm a previous suggestion that the observed photo-ionized line emission originates from a confined region in the outer edge of the accretion disk near the hot spot. Line properties allow us to impose limits on the size of accretion disk, the central corona, and the emission region. The photo-ionized plasma is consistent with ionization parameters of log(xi) > 2, and when combined with disk size and reasonable assumptions for the plasma density, this suggests illuminating disk luminosities which are over an order of magnitude higher than what is actually observed. That is, we do not directly observe the central emitting X-ray source. The spectral continua are best fit by a flat power law with a high energy cut-off and partial covering absorption (N_H ranging from 5.4-6.3x10^{22} cm^{-2}) with a covering fraction of about 50%. We discuss some implications of our findings with respect to the photo-ionized line emission for the basic properties of the X-ray source.Comment: Submitted to the Astrophysical Journa

    CK2 Inhibitors Increase the Sensitivity of HSV-1 to Interferon-β

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    Herpes simplex virus type 1 (HSV-1) requires the activities of cellular kinases for efficient replication. The host kinase, CK2, has been shown or is predicted to modify several HSV-1 proteins and has been proposed to affect one or more steps in the viral lifecycle. Furthermore, potential cellular and viral substrates of CK2 are involved in antiviral pathways and viral counter-defenses, respectively, suggesting that CK2 regulates these processes. Consequently, we tested whether pharmacological inhibitors of CK2 impaired HSV-1 replication, either alone or in combination with the cellular antiviral factor, interferon-β (IFN-β). Our results indicate that the use of CK2 inhibitors results in a minor reduction in HSV-1 replication but enhanced the inhibitory effect of IFN-β on replication. This effect was dependent on the HSV-1 E3 ubiquitin ligase, infected cell protein 0 (ICP0), which impairs several host antiviral responses, including that produced by IFN-β. Inhibitors of CK2 did not, however, impede the ability of ICP0 to induce the degradation of two cellular targets: the promyelocyticleukemia protein (PML) and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Notably, this effect was only apparent for HSV-1, as the CK2 inhibitors did not enhance the antiviral effect of IFN-β on either vesicular stomatitis virus or adenovirus type 5. Thus, our data suggest that the activity of CK2 is required for an early function during viral infection that assists the growth of HSV-1 in IFN-β-treated cells

    Algal Remediation of Wastewater Produced from Hydrothermally Treated Septage

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    Hydrothermal carbonization (HTC) is a promising technology to convert wet wastes like septic tank wastes, or septage, to valuable platform chemical, fuels, and materials. However, the byproduct of HTC, process liquid, often contains large amount of nitrogen species (up to 2 g/L of nitrogen), phosphorus, and a variety of organic carbon containing compounds. Therefore, the HTC process liquid is not often treated at wastewater treatment plant. In this study, HTC process liquid was treated with algae as an alternative to commercial wastewater treatment. The HTC process liquid was first diluted and then used to grow Chlorella sp. over a short period of time (15 days). It was found that the algae biomass concentration increased by 644 mg/L over the course of 10 days, and which subsequently removed a majority of the nutrients in the HTC process liquid. Around 600 mg/L of algal biomass was collected in the process liquid at the end of treatment (day 15). Meanwhile, chemical oxygen demand (COD), total phosphorous, total Kheldjal nitrogen, and ammonia were reduced by 70.0, 77.7, 82.2, and 99.0% by fifteen days compared to the untreated wastewater, respectively. This study demonstrates that HTC process liquid can be treated by growing algae creating a potential replacement for expensive synthetic nutrient feeds for algal production

    Considerations on repeated repairing of weldments in Inconel 718 alloy

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    The effects of repeated weld repairs on the metallurgical characteristics, high cycle fatigue (HCF), and tensile properties of Inconel 718 butt weld joints were determined. A 1/4 in thick plate and a 1/2 in thick plate were used as well as tungsten inert gas welding, and Inconel 718 filler wire. Weld panels were subjected to 2, 6, and 12 repeated repairs and were made in a highly restrained condition. Post weld heat treatments were also conducted with the welded panel in the highly restrained condition. Results indicate that no significant metallurgical anomaly is evident as a result of up to twelve repeated weld repairs. No degradation in fatigue life is noted for up to twelve repeated repairs. Tensile results from specimens which contained up to twelve repeated weld repairs revealed no significant degradation in UTS and YS. However, a significant decrease in elongation is evident with specimens (solution treated and age hardened after welding) which contained twelve repeated repairs. The elongation loss is attributed to the presence of a severe notch on each side (fusion line) of the repair weld bead reinforcement
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