Influence of climatography on rainfall thresholds for initiation of debris-flows on the California coast [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Since 1986, the U.S. Geological Survey and National Weather Service have operated a warning system for debris flows triggered by severe rainstorms in the San Francisco Bay region. The NWS tracks storm systems as they approach the region, forecasts precipitation, and observes rainfall with a network of radiotelemetered rain gauges (ALERT). The USGS also monitors ALERT data and compares the observed and forecast rainfall to thresholds for debris-flow initiation. Both groups jointly assess debris-flow hazards and issue public advisories when rainfall conditions reach or approach critical levels.

Absence of association between SNPs in the promoter region of the insulin-like growth factor 1 (IGF-1) gene and longevity in the Han Chinese population

Previous studies have indicated that genetic variations in the factors of insulin/insulin-like growth factor 1 (IGF-1) signaling pathway could influence human life-span by affecting IGF-1 levels. The promoter region of the IGF-1 gene is an obvious candida

A note on recent advances in the genetic characterization of tilapia stocks in Lake Victoria region

Oreochromis esculenta, the original "ngege" is virtually extinct in Lake Victoria, and is limited to satellite lakes and reservoirs in the greater Lake Victoria region. Oreochromis variabilis can still be found in Lake Victoria and some satellite lakes in the Kyoga System, but in small numbers and only at a few localities (WANDERA and KAUFMAN, unpub. data). Little is known about the influence that species translocations have had on the genetic structure of these crucial fishery species, and even the source of the parent stocks for the introductions remain obscure. Genetic variability was examined within and among allopatric populations of three species in the tilapiine genus Oreochromis: O. esculentus (endemic to Lakes Victoria and Kyoga), and two exotic species introduced to Lake Victoria in the late 1950's to supplement the failing fisheries for native tilapiines, O. niloticus and O. leucostictus.

Influence of ground anchors on topographic amplification at slope crests

One feature of earthquake loading in regions containing sloping ground is a marked increase in accelerations at the crests of slopes. Many field cases exist where such increased accelerations were measured. The observed increase in the amount and severity of observed building damage near the edge of cliff-type topographies has been attributed to the topographic amplification. To counter this, it has been shown that anchoring the soil mass responsible for this to the rest of the stable soil mass can reduce the amount of topographic amplification. In this study, dynamic centrifuge modelling will be used to identify the region affected by topographic amplification in a model slope. The soil accelerations recorded will be compared to those measured in a comparable model treated by anchors. In addition, the tension measured in the anchors will be examined in order to better understand how the anchors are transferring the loads and mitigating these amplifications. © 2010 Taylor & Francis Group, London.

Influence of specific HSP70 domains on fibril formation of the yeast prion protein Ure2.

Ure2p is the protein determinant of the Saccharomyces cerevisiae prion state [URE3]. Constitutive overexpression of the HSP70 family member SSA1 cures cells of [URE3]. Here, we show that Ssa1p increases the lag time of Ure2p fibril formation in vitro in the presence or absence of nucleotide. The presence of the HSP40 co-chaperone Ydj1p has an additive effect on the inhibition of Ure2p fibril formation, whereas the Ydj1p H34Q mutant shows reduced inhibition alone and in combination with Ssa1p. In order to investigate the structural basis of these effects, we constructed and tested an Ssa1p mutant lacking the ATPase domain, as well as a series of C-terminal truncation mutants. The results indicate that Ssa1p can bind to Ure2p and delay fibril formation even in the absence of the ATPase domain, but interaction of Ure2p with the substrate-binding domain is strongly influenced by the C-terminal lid region. Dynamic light scattering, quartz crystal microbalance assays, pull-down assays and kinetic analysis indicate that Ssa1p interacts with both native Ure2p and fibril seeds, and reduces the rate of Ure2p fibril elongation in a concentration-dependent manner. These results provide new insights into the structural and mechanistic basis for inhibition of Ure2p fibril formation by Ssa1p and Ydj1p.

Influence of tire geometry on the horn effect

A reciprocal-configuration Boundary Element Method calculation of acoustic radiation characteristics has been implemented for a generic tire geometry. The influence of the geometric parameters on the radiation characteristics has been studied. The degree of amplification of noise sources on the tire belt is strongly affected by the overall tire width. In contrast, the tire radius predominantly influences the pattern of the varying amplification around the belt, rather than its absolute level. Radiusing the tire's 'shoulder' region is potentially beneficial in terms of lowering amplification levels, for a tire of fixed overall width. However, it is less effective than maintaining sharp shoulders and reducing the overall width. Thus, for an acoustically optimal belted tire, the overall width should be as small as possible, even if this leads to a larger diameter. The width should not be increased in order to accommodate a radiused crown region. Copyright © (2012) by the Institute of Noise Control Engineering (INCE).

Influence of specific HSP70 domains on fibril formation of the yeast prion protein Ure2.

Ure2p is the protein determinant of the Saccharomyces cerevisiae prion state [URE3]. Constitutive overexpression of the HSP70 family member SSA1 cures cells of [URE3]. Here, we show that Ssa1p increases the lag time of Ure2p fibril formation in vitro in the presence or absence of nucleotide. The presence of the HSP40 co-chaperone Ydj1p has an additive effect on the inhibition of Ure2p fibril formation, whereas the Ydj1p H34Q mutant shows reduced inhibition alone and in combination with Ssa1p. In order to investigate the structural basis of these effects, we constructed and tested an Ssa1p mutant lacking the ATPase domain, as well as a series of C-terminal truncation mutants. The results indicate that Ssa1p can bind to Ure2p and delay fibril formation even in the absence of the ATPase domain, but interaction of Ure2p with the substrate-binding domain is strongly influenced by the C-terminal lid region. Dynamic light scattering, quartz crystal microbalance assays, pull-down assays and kinetic analysis indicate that Ssa1p interacts with both native Ure2p and fibril seeds, and reduces the rate of Ure2p fibril elongation in a concentration-dependent manner. These results provide new insights into the structural and mechanistic basis for inhibition of Ure2p fibril formation by Ssa1p and Ydj1p.

Influence of dew on biomass and photosystem II activity of cyanobacterial crusts in the Hopq Desert, northwest China

Dew is an important water source for desert organisms in semiarid and arid regions. Both field and laboratory experiments were conducted to investigate the possible roles of dew in growth of biomass and photosynthetic activity within cyanobacterial crust. The cyanobacteria, Microcoleus vaginatus Gom. and Scytonema javanicum (Kutz.) Born et Flah., were begun with stock cultures and sequential mass cultivations, and then the field experiment was performed by inoculating the inocula onto shifting sand for forming cyanobacterial crust during late summer and autumn of 2007 in Hopq Desert, northwest China. Measurements of dew amount and Chlorophyll a content were carried out in order to evaluate the changes in crust biomass following dew. Also, we determined the activity of photosystem II(PSII) within the crust in the laboratory by simulating the desiccation/rehydration process due to dew. Results showed that the average daily dew amount as measured by the cloth-plate method (CPM) was 0.154 mm during fifty-three days and that the crust biomass fluctuated from initial inoculation of 4.3 mu g Chlorophyll a cm(-2) sand to 5.8-7.3 mu g Chlorophyll a cm(-2) crust when dew acted as the sole water source, and reached a peak value of approximately 8.2 mu g Chlorophyll a cm(-2) crust owing to rainfalls. It indicated that there was a highly significant correlation between dew amounts and crust moistures (r = 0.897 or r = 0.882, all P < 0.0001), but not a significant correlation between dew and the biomass (r = 0.246 or r = 0.257, all P > 0.05), and thus concluded that dew might only play a relatively limited role in regulating the crust biomass. Correspondingly, we found that rains significantly facilitated biomass increase of the cyanobacterial crust. Results from the simulative experiment upon rehydration showed that approximately 80% of PSII activity could be achieved within about 50 min after rehydration in the dark and at 5 degrees C, and only about 20% of the activity was light-temperature dependent. This might mean that dew was crucial for cyanobacterial crust to rapidly activate photosynthetic activity during desiccation and rehydration despite low temperatures and weak light before dawn. It also showed in this study that the cyanobacterial crusts could receive and retain more dew than sand, which depended on microclimatic characteristics and soil properties of the crusts. It may be necessary for us to fully understanding the influence of dew on regulating the growth and activity of cyanobacterial crust, and to soundly evaluate the crust's potential application in fighting desertification because of the available water due to dew. (C) 2009 Published by Elsevier Ltd.

Influence of spacer layer thickness on the current-voltage characteristics of pseudomorphic AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes

This paper investigates the dependence of current-voltage characteristics of AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes (RTDs) on spacer layer thickness. It finds that the peak and the valley current density J in the negative differential resistance (NDR) region depends strongly on the thickness of the spacer layer. The measured peak to valley current ratio of RTDs studied here is shown to improve while the current density through RTDs decreases with increasing spacer layer thickness below a critical value.

Influence of fused interface on the optical and thermal characteristics of vertical cavity lasers

From the effective absorption coefficient of bonded interface and the relationship of interface to reflectivity at cavity mode for double bonded vertical cavity laser, it can be seen that bonded interfaces should be positioned at the null of standing wave distribution, and the thickness of interface should be less than 20 nm. Using the finite elements method, the temperature contour map of laser can be calculated. Results showed that the influence of thin interface to thermal characteristics of VCSELS is slight, while thick interface will lead to temperature increase of active region. SEM images demonstrate that hydrophobic bonding is suitable for the fabrication of the device, while hydrophilic bonding interface is unfavorable to optical and thermal properties of devices with interface thickness larger than 40 nm.

A new p-n structure ultraviolet photodetector with p(-)-GaN active region

A new ultraviolet photodetector of employing p menus type GaN (p(-)-GaN) as the active layer is proposed. It is easy to obtain the p(-)-GaN layer with low carrier concentration. As a result, the depletion region can be increased and the quantum efficiency can be improved. The influence of some structure parameters on the performance of the new device is investigated. Through the simulation calculation, it is found that the quantum efficiency increases with the decrease of the barrier height between the metal electrode and the p(-)-GaN layer, and it is also found that the quantum efficiency can be improved by reducing the thickness of the p(-)-GaN layer. To fabricate the new photodetector with high performance, we should employ thin p(-)-GaN layer as the active layer and reduce the Schottky barrier height.

SiO2/Ta interface reaction in magnetic multilayers and its influence on Ta buffer layers

Ta is often used as a buffer layer in magnetic multilayers. In this study, Ta/Ni81Fe19/Ta multilayers were deposited by magnetron sputtering on sing-crystal Si with a 300-nm-thick SiO2 film. The composition and chemical states at the interface region of SiO2/Ta were studied using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that there is an 'inter-mixing layer" at the SiO2/Ta interface due to a thermodynamically favorable reaction: 15 SiO2 + 37 Ta = 6 Ta2O5 + 5 Ta5Si3. Therefore, the Ta buffer layer thickness used to induce NiFe (111) texture increases.

Influence of lateral propagating modes on laser output characteristics in selectively oxidized vertical cavity surface-emitting lasers with double oxide layers

The influence of lateral propagating modes on the threshold current and the spontaneous emission factor in selectively oxidized vertical cavity surface-emitting lasers (VCSELs) is investigated based on the mode behaviors of lateral propagating modes and the rate equation model. The numerical results show that the lateral propagating modes may be trapped in the aperture region for the selectively oxidized VCSEL with two oxide layers, one above and one below the active region. The output characteristics of VCSELs can be affected due to the reabsorption of the quasitrapped lateral propagating modes. A lower threshold current can be expected for a VCSEL with double oxide layers than that with a single oxide layer. The numerical results of rate equations also show that a larger spontaneous emission factor can be obtained by fitting the output-input curves for the VCSEL with double oxide layers. (C) 1999 American Institute of Physics. [S0021-8979(99)07919-0].

Influence of a tilted cavity on quantum-dot optoelectronic active devices

Quantum-dot laser diodes (QD-LDs) with a Fabry-Perot cavity and quantum-dot semiconductor optical amplifiers (QD-SOAs) with 7° tilted cavity were fabricated. The influence of a tilted cavity on optoelectronic active devices was also investigated. For the QD-LD, high performance was observed at room temperature. The threshold current was below 30 mA and the slope efficiency was 0.36 W/A. In contrast, the threshold current of the QD-SOA approached 1000 mA, which indicated that low facet reflectivity was obtained due to the tilted cavity design.A much more inverted carrier population was found in the QD-SOA active region at high operating current, thus offering a large optical gain and preserving the advantages of quantum dots in optical amplification and processing applications. Due to the inhomogeneity and excited state transition of quantum dots, the full width at half maximum of the electroluminescence spectrum of the QD-SOA was 81.6 nm at the injection current of 120 mA, which was ideal for broad bandwidth application in a wavelength division multiplexing system. In addition, there was more than one lasing peak in the lasing spectra of both devices and the separation of these peak positions was 6-8 nm,which is approximately equal to the homogeneous broadening of quantum dots.

Influence of processing temperature on microstructure and microhardness of copper subjected to high-pressure torsion

Cu samples were subjected to high-pressure torsion (HPT) with up to 6 turns at room temperature (RT) and liquid nitrogen temperature (LNT), respectively. The effects of temperature on grain refinement and microhardness variation were investigated. For the samples after HPT processing at RT, the grain size reduced from 43 mu m to 265 nm, and the Vickers microhardness increased from HV52 to HV140. However, for the samples after HPT processing at LNT, the value of microhardness reached its maximum of HV150 near the center of the sample and it decreased to HV80 at the periphery region. Microstructure observations revealed that HPT straining at LNT induced lamellar structures with thickness less than 100 nm appearing near the central region of the sample, but further deformation induced an inhomogeneous distribution of grain sizes, with submicrometer-sized grains embedded inside micrometer-sized grains. The submicrometer-sized grains with high dislocation density indicated their nonequilibrium nature. On the contrary, the micrometer-sized grains were nearly free of dislocation, without obvious deformation trace remaining in them. These images demonstrated that the appearance of micrometer-sized grains is the result of abnormal grain growth of the deformed fine grains.