Fully coordinated silica nanoclusters: (SiO2)(N) molecular rings

A new form of finite silica with edge-sharing SiO2 units connected in a ring is proposed. High-level density-functional calculations for (SiO2)(N), N = 4-14, show the rings to be energetically more stable than the corresponding (SiO2)(N) linear chains for N > 11. The rings display frequency modes in remarkable agreement with infrared bands measured on dehydrated silica surfaces indicating their potential as models of strained extended silica systems. Silica rings, if synthesized, may also be useful precursors for new bulk-silica polymorphs with tubular or porous morphologies

Apparent Scarcity of Low-Density Polymorphs of Inorganic Solids

For most inorganic solids, very few dense polymorphs and no low-density polymorphs are observed. Taking a wide range of tetrahedrally-coordinated binary solids (e.g., ZnO, GaN) as a prototypical system, we show that the apparent scarcity of low-density polymorphs is not due to significant structural or energetic limitations. Using databases of periodic networks as sources of novel crystal structures, followed by ab initio energy minimization, we predict a dense spectrum of low-density low-energy polymorphs. The diverse range of materials considered indicates that this is likely to be a general phenomenon

Influence of acute caffeine on 50-kHz ultrasonic vocalizations in male adult rats and relevance to caffeine-mediated psychopharmacological effects

To further characterize caffeine-mediated psychopharmacological effects, the present study investigated whether acute caffeine (3, 10, 30, 50 mg/kg i.p.) exerted any influence on the emission and features of ultrasonic vocalizations (USVs), which are thought to index changes involving emotional state, in male adult rats. The results obtained demonstrate that caffeine can trigger modifications in the maximum peak frequency and bandwidth of the 50-kHz range USVs. However, such an effect was not accompanied by a significant elevation in the number of 50-kHz USVs, relative to administration of vehicle. Under the same experimental conditions, acute amphetamine (2 mg/kg i.p.) robustly elevated the number of 50-kHz USVs emitted by rats, although it did not affect the maximum peak frequency and bandwidth of USVs. Thus, both qualitative and quantitative differences in the effects exerted by caffeine and amphetamine on 50-kHz USVs were observed. Taken together, these findings further clarify the features of caffeine-mediated psychopharmacological effects, and may help to elucidate the differences between the central effects of caffeine and those elicited by other psychostimulant

Workplace Incivility: A Quantitative Study of Public University Staff Member Experiences in the Northeast

Workplace incivility is a construct similar to sexual harassment or bullying in that it is unwanted behavior and can cause negative emotions for those who experience it. However, it lacks the clear definition and legal repercussions that have been established for sexual harassment and bullying

Chemical characteristics of air from different source regions during the second Pacific Exploratory Mission in the Tropics (PEM-Tropics B)

Ten-day backward trajectories are used to determine the origins of air parcels arriving at locations of airborne DC-8 chemical measurements during NASA's second Pacific Exploratory Mission in the Tropics B that was conducted during February-April 1999. Chemical data at sites where the trajectories had a common geographical origin and transport history are grouped together, and statistical measures of chemical characteristics are computed. Temporal changes in potential temperature are used to determine whether trajectories experienced a significant convective influence during the 10-day period. Trajectories describing the aged marine Southern Hemispheric category remain over the South Pacific Ocean during the 10-day period, and their corresponding chemical signature indicates very clean air. The category aged marine air in the Northern Hemisphere is found to be somewhat dirtier. Subdividing its trajectories based on the direction from which the air had traveled is found to be important in explaining the various chemical signatures. Similarly, long-range northern hemispheric trajectories passing over Asia are subdivided depending on whether they had followed a mostly zonal path, had originated near the Indian Ocean, or had originated near Central or South America and subsequently experienced a stratospheric influence. Results show that the chemical signatures of these subcategories are different from each other. The chemical signature of the southern hemispheric long-range transport category apparently exhibits the effects of pollution from Australia, southern Africa, and South America. Parcels originating over Central and northern South America are found to contain the strongest pollution signature of all categories, due to biomass burning and other sources. The convective category exhibits enhanced values of nitrogen species, probably due to emissions from lightning associated with the convection. Values of various species, including peroxides and acids, confirm that parcels were influenced by the removal of soluble gas and particle species due to precipitation. Finally, current results are compared with those from the first PEM-Tropics mission that was conducted in the same region during the southern hemispheric dry season (August-October 1996) when extensive biomass burning occurred. Results show that air samples during PEM-Tropics B are considerably cleaner than those of its dry season counterpart. Copyright 2001 by the American Geophysical Union

Performance analysis of a parallel, multi-node pipeline for DNA sequencing

Post-sequencing DNA analysis typically consists of read mapping followed by variant calling and is very time-consuming, even on a multi-core machine. Recently, we proposed Halvade, a parallel, multi-node implementation of a DNA sequencing pipeline according to the GATK Best Practices recommendations. The MapReduce programming model is used to distribute the workload among different workers. In this paper, we study the impact of different hardware configurations on the performance of Halvade. Benchmarks indicate that especially the lack of good multithreading capabilities in the existing tools (BWA, SAMtools, Picard, GATK) cause suboptimal scaling behavior. We demonstrate that it is possible to circumvent this bottleneck by using multiprocessing on high-memory machines rather than using multithreading. Using a 15-node cluster with 360 CPU cores in total, this results in a runtime of 1 h 31 min. Compared to a single-threaded runtime of similar to 12 days, this corresponds to an overall parallel efficiency of 53%

Assessing the effectiveness of public awareness-raising initiatives for the Hainan gibbon Nomascus hainanus

Many protected areas conduct awareness-raising activities to increase local knowledge and support conservation programmes, but the effectiveness of such activities is rarely assessed. Public awareness-raising has been carried out since the early 2000s around Bawangling National Nature Reserve, Hainan, China, to improve conservation knowledge about the Critically Endangered Hainan gibbon Nomascus hainanus, one of the rarest mammals. We conducted 207 interviews in 25 villages around Bawangling National Nature Reserve to evaluate the outcome of previous conservation education, through comparison of variation in local respondent knowledge and attitudes, and specific enquiries about sources of knowledge acquisition. Likelihood of accurate responses to most of our questions regarding the species was positively correlated with local exposure to gibbon-themed billboards and murals, and respondents exhibited greater knowledge about several key conservation indices for gibbons compared to their knowledge about sympatrically occurring rhesus macaques Macaca mulatta. Many respondents specifically reported they knew about local existence, population size, conservation status, and threats to gibbons from past awareness-raising activities, with village education sessions and billboards widely identified as key sources of information. However, other known awareness-raising approaches have had little detectable effect on shaping local conservation awareness. Although educational activities have improved awareness about gibbons and their conservation requirements in relative terms, overall levels of knowledge remain low in many important areas and ongoing improvement of local awareness is still needed, in particular around poorly-understood topics such as gibbon conservation status, rarity and threats, and for socio-demographic groups possessing less conservation knowledge

Evaluation of antagonistic fungi against charcoal rot of sunflower caused by Macrophomina phaseolina (Tassi) Goid.

In vitro, sensitivity of Macrophomina phaseolina (Tassi) Goid determined through inhibition zone technique to various antagonistic fungi viz., Aspergillus niger, Aspergillus flavus, Trichoderma viride, Trichoderma harzianum and Penicillium capsulatum amended into PDA medium. All the antagonists reduced the colony growth of M. Phaseolina significantly compared to the control A. flavus was proved to be the most effective (66.00%) in reducing the colony growth of M. Phaseolina followed by A. niger (55.55%), T. viride (51.11%), T. harzianum (26.67%) and P. capsulatum (11.11%) respectively over control. A. flavus due to it antifungal metabolites activities was the most effective while P. capsulatum was the least effective. Seeds of four varieties treated with the culture of A. flavus, A. niger, T. viride and P. capsulatum and there combinations were sown in pots having infested soil (M. phaseolina). Results showed reduction in disease incidence of charcoal rot on sunflower cultivar G-66 with antagonist, A. flavus (100%) followed by A. niger (64.86%) P. capsulatum (63.79%) and T. viride (31.89%) over control. Decrease in disease incidence over control was 100% where seed was treated with combination of A. niger and A. flavus while A. niger and T. viride combination was least effective on G-66 (30.80%). All antagonists reduced the disease incidence on G-66 (Highly resistant), HRBS-1, (Resistant), G-72 (Moderately susceptible) and G-51 (susceptible) but were most effective on highly resistant variety (G-66) while least effective on susceptible variety (G-51).Key words: Sunflowers, Macrophomina phaseolina, antagonistic fungi