15,529 research outputs found
Kinesin Light Chains Are Essential for Axonal Transport in Drosophila
Kinesin is a heterotetramer composed of two 115-kD heavy chains and two 58-kD light chains. The microtubule motor activity of kinesin is performed by the heavy chains, but the functions of the light chains are poorly understood. Mutations were generated in the Drosophila gene Kinesin light chain (Klc), and the phenotypic consequences of loss of Klc function were analyzed at the behavioral and cellular levels. Loss of Klc function results in progressive lethargy, crawling defects, and paralysis followed by death at the end of the second larval instar. Klc mutant axons contain large aggregates of membranous organelles in segmental nerve axons. These aggregates, or organelle jams (Hurd, D.D., and W.M. Saxton. 1996. Genetics. 144: 1075-1085), contain synaptic vesicle precursors as well as organelles that may be transported by kinesin, kinesin-like protein 68D, and cytoplasmic dynein, thus providing evidence that the loss of Klc function blocks multiple pathways of axonal transport. The similarity of the Klc and Khc ((Saxton et al. Cell 64:1093-1102; Hurd, D.D., and W.M. Saxton. 1996. Genetics 144: 1075-1085) mutant phenotypes indicates that KLC is essential for kinesin function, perhaps by tethering KHC to intracellular cargos or by activating the kinesin motor
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Entrepreneurship and economic development in cities
Policy makers have identified the relationship between entrepreneurship and economic development. Yet, little is known about how this relationship varies over time in cities with different market sizes. This study examines the link between entrepreneurship and economic development using a panel of 127 European cities between 1994 and 2009. We found that the immediate economic development impact of new firm start-ups is positive for both small-/medium-size cities and large cities. The relationship is U-shaped for large cities, with the indirect effect taking 7 years, but the indirect effect does not occur in small-/medium-size cities. We offer useful information for policy makers, practitioners, and scholars
Chip equalized adaptive rake receiver for DS-CDMA UWB systems
Conventional Rake receiver is a popular and effective method of utilizing the diversity offered by a DS-CDMA and multipath communication channel. The proposed Rake receiver is useful for suppression of multiple access interference in a multipath channel. The receiver works on chip level equalization on each Rake finger to cancel multi-access interference. Simulation results show that the convergence, diversity gain and bit error probability performance of the proposed receiver is much better than conventional adaptive Rake receiver in multipath channels
The Spectral Energy Distribution and Infrared Luminosities of z ≈ 2 Dust-obscured Galaxies from Herschel and Spitzer
Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L_(IR) > 10^(12) L_☉). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10^(11.6) L_☉ 10^(13) L_☉. The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with "power-law" SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar "bump" in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ~25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L_(IR)(8-1000 μm)/νL_ν(8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 "infrared main sequence" of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up versions of local ULIRGs in terms of 250/24 μm flux density ratio, and IR8, they tend to have cooler far-IR dust temperatures (20-40 K for DOGs versus 40-50 K for local ULIRGs) as measured by the rest-frame 80/115 μm flux density ratios (e.g., observed-frame 250/350 μm ratios at z = 2). DOGs that are not detected by Herschel appear to have lower observed-frame 250/24 μm ratios than the detected sample, either because of warmer dust temperatures, lower IR luminosities, or both
Frequency and time hopping PPM UWB multiple access communication scheme
In this paper we propose frequency and time hopping pulse position modulation (FTH-PPM) ultra wideband (UWB) for multiple access communications.We have derived and investigated the bit error probability for the multi-user synchronous transmitter case in multipath channels with Additive White Gaussian Noise (AWGN). Simulation results show that bit error probability performance of FTH-PPM UWB out performs the time hopping pulse position modulated (TH-PPM) UWB system. It also show that multiuser capacity of FTH-PPM UWB system is much better than TH-PPM UWB system
Monojet searches for momentum-dependent dark matter interactions
We consider minimal dark matter scenarios featuring momentum-dependent couplings of the dark sector to the Standard Model. We derive constraints from existing LHC searches in the monojet channel, estimate the future LHC sensitivity for an integrated luminosity of 300 fb−1, and compare with models exhibiting conventional momentum-independent interactions with the dark sector. In addition to being well motivated by (composite) pseudo-Goldstone dark matter scenarios, momentum-dependent couplings are interesting as they weaken direct detection constraints. For a specific dark matter mass, the LHC turns out to be sensitive to smaller signal cross-sections in the momentum-dependent case, by virtue of the harder jet transverse-momentum distribution
Dynamic response of phenolic resin and its carbon-nanotube composites to shock wave loading
We investigate with nonreactive molecular dynamics simulations the dynamic response of phenolic resin and its carbon-nanotube (CNT) composites to shock wave compression. For phenolic resin, our simulations yield shock states in agreement with experiments on similar polymers except the
“phase change” observed in experiments, indicating that such phase change is chemical in nature. The elastic–plastic transition is characterized by shear stress relaxation and atomic-level slip, and phenolic resin shows strong strain hardening. Shock loading of the CNT-resin composites is applied parallel or perpendicular to the CNT axis, and the composites demonstrate anisotropy in wave
propagation, yield and CNT deformation. The CNTs induce stress concentrations in the composites and may increase the yield strength. Our simulations suggest that the bulk shock response of the composites depends on the volume fraction, length ratio, impact cross-section, and geometry of the CNT components; the short CNTs in current simulations have insignificant effect on the bulk
response of resin polymer
Bioefficacy of Imidacloprid 350 SC against sucking insect-pests in chilli (Capsicum annum L.)
A field experiment was conducted in a RBD at Horticulture farm, Rajasthan College of Agriculture, Udaipur to evaluate the bioefficacy of Imidacloprid 350 SC at 100, 125 and 150 ml/ha against sucking pests of chilli during Kharif, 2013 and 2014. The highest reduction in the population of aphid, jassids and thrips in chilli was recorded in case of two spray of Imidacloprid 350 SC at 150 ml/ha and also recorded highest marketable yield of 161.25 and 164.88 q/ha during 2013 and 2014, respectively. It was found at par to Imidacloprid 350 SC at 125 ml/ha
Solar Gamma Rays Powered by Secluded Dark Matter
Secluded dark matter models, in which WIMPs annihilate first into metastable
mediators, can present novel indirect detection signatures in the form of gamma
rays and fluxes of charged particles arriving from directions correlated with
the centers of large astrophysical bodies within the solar system, such as the
Sun and larger planets. This naturally occurs if the mean free path of the
mediator is in excess of the solar (or planetary) radius. We show that existing
constraints from water Cerenkov detectors already provide a novel probe of the
parameter space of these models, complementary to other sources, with
significant scope for future improvement from high angular resolution gamma-ray
telescopes such as Fermi-LAT. Fluxes of charged particles produced in mediator
decays are also capable of contributing a significant solar system component to
the spectrum of energetic electrons and positrons, a possibility which can be
tested with the directional and timing information of PAMELA and Fermi.Comment: 22 pages, 3 figure
Research in the assessment of capture and culture fisheries along the Indian coast
A review of the research conducted at National Institute of Oceanography, Goa to assess the
capture and culture fishery potential of India is presented in the paper- the primary, secondary and
benthic productivity of estuaries and backwaters are elucidated by taking the Mandovi-Zuari estuarine
system as an example. The productivity of the coastal and oceanic waters around India are discussed.
The expected fishery yield and present level of exploitation are assessed and further course of action
discussed in this paper, in culture fisheries the contributions of NIO in the fields of mussel culture,
shrimp culture, brine shrimp culture, seaweed culture, horse-shoe crab culture and fish culture are reviewed
and discussed
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