Measurement of the effect of Amazon smoke on inhibition of cloud formation

Urban air pollution and smoke from fires have been modeled to reduce cloud formation by absorbing sunlight, thereby cooling the surface and heating the atmosphere. Satellite data over the Amazon region during the biomass burning season showed that scattered cumulus cloud cover was reduced from 38%in clean conditions to 0%for heavy smoke (optical depth of 1.3). This response to the smoke radiative effect reverses the regional smoke instantaneous forcing of climate from -28 watts per square meter in cloud-free conditions to +8 watts per square meter once the reduction of cloud cover is accounted for.     

Evaluation of semiochemical toxicity to Aedes aegypti,Ae. albopictus and Anopheles quadrimaculatus (Diptera: Culicidae)

BACKGROUND: Mosquitoes are the most important vectors of human pathogens. Wide‐scale use of pesticides has led to the development of resistance to most common insecticide groups. The need to develop novel products that have a low impact on human health and the environment is well established. The toxicity of selected semiochemicals with molecular structures indicative of insecticidal activity was determined against adult Aedes aegypti (L.) and Anopheles quadrimaculatus (Say). The two most active insecticides against Ae. aegypti were also evaluated against Ae. albopictus (Skuse). RESULTS: Fifteen semiochemicals classified as terpenoid alcohols, ketones or carboxylic esters showed toxicity to both mosquito species. Geranyl acetone (LC₅₀ = 38.51 µg cm^?2) followed by citronellol (LC₅₀ = 48.55 µg cm^?2) were the most toxic compounds to Ae. aegypti, while geraniol and lavonax, with LC₅₀ values of 31.88 and 43.40 µg cm^?2, showed the highest toxicity to An. quadrimaculatus. Both geranyl acetone and citronellol were highly toxic to Ae. albopioctus. No semiochemical showed fumigation activity against either species. All semiochemicals persisted for less than 24 h when tested on filter paper. CONCLUSION: Quantification of LC₅₀ values of several semiochemicals against Ae. Aegypti, An. quadrimaculatus and Ae. albopioctus showed that semiochemicals not only modify insect behaviors but also hold potential as potent insecticides for mosquito control programs. Copyright © 2010 Society of Chemical Industry     

Green and non-green callus induction from excised rice (Oryza sativa) embryos: effects of exogenous plant growth regulators

Calli were induced either from excised rice embryos or from whole seeds in the presence of 1 to 5 mg l-1 NAA. After 12 days of culture, calli were induced only from excised rice embryos. We found that excised embryos accumulated NAA up to 6 times higher concentration than did whole seeds. In the presence of 1 to 5 mg l-1 NAA and 2 to 10 mg l-1 kinetin, chlorophyllous calli were induced from excised rice embryos. Chlorophyll contents in the callus tissue increased with increasing kinetin concentration while percent callus induction decreased. The total chlorophyll content was linearly correlated with the ratio of kinetin to NAA in the medium.     

Rates of elementary reactions: measurement and applications

Modern experimental techniques for measuring rate parameters of elementary reactions have transformed the field of gas-phase reaction kinetics from one of indirect inference to one of direct determination. Recent progress in the principal techniques is described, a few examples are given of the hundreds of elementary reactions for which rate information has become available, and comparison with reaction rate theory is briefly discussed. Some generalizations regarding the dependence of rate parameters on structure and thermodynamics are drawn, and successful applications to atmospheric and combustion modeling and measurement are presented.     

Somatically evoked magnetic fields of the human brain

The human brain is found to produce a magnetic field near the scalp which varies in synchrony with periodic electrical stimulation applied to a finger. Use of a highly sensitive superconducting quantum interference device as a magnetic field detector reveals that the brain's field is sharply localized over the primary projection area of the sensory cortex contralateral to the digit being stimulated. The phase of the response at the stimulus frequency varies monotonically with the repetition rate and at intermediate frequencies yields a latency of approximately 70 milliseconds for cortical response.     

Assessing ecological changes in and around marine reserves using community perceptions and biological surveys

1. Well‐enforced partial or total no‐fishing zones (collectively known as marine protected areas, or MPAs) can help restore degraded coral reefs and enhance fish populations. 2. A comparison was made of community perceptions of ecological changes in an MPA with concurrent scientific data on these changes in the same MPA. Such analyses are particularly important in community‐based MPAs where local support is a key determinant of ecological success. 3. The no‐take MPA in question was initially launched in partnership with the community in 1995 and formalized in 1998. The perceptions data come from interviews with community members in 1999 and 2004, the biological data come from underwater visual censuses of the MPA from 1998 to 2004. 4. Community members perceived more fish within the MPA and slight increases in catch outside the MPA. In contrast, fish censuses showed a high degree of stochastic variation and only minor increases in fish abundance, size and diversity in and around the MPA between 1998 and 2004. 5. Possible explanations for these discrepancies include different temporal, spatial or species frames of reference and/or limitations to the biological survey technique. Other options include wishful thinking, external influences, a desire to please, or confounding with other benefits. 6. This study demonstrates some of the strengths and weaknesses of community perceptions and biological data. In order to improve our understanding about the changes that occur over time in an MPA and engender community support for the long‐term viability of MPAs, it is important to develop diverse and efficient monitoring schemes. Copyright © 2010 John Wiley & Sons, Ltd.     

Efficacy of chlorfenapyr (AC 303630) experimental pour-on and CyLence formulations against naturally acquired louse infestations on cattle in New York

The four chlorfenapyr formulations examined provided 100% control of both the nymphal and adult stages of naturally acquired Bovicola bovis (L.) on cattle up to 35 days after application. Treatment with 6mg chlorfenapyr per kg BW in a 0.12ml per kg BW formulation was as effective as treatment with CyLence (cyfluthrin) in controlling naturally acquired Solenopotes capillatus (Enderlein) on cattle for 35 days. Percent reduction was never greater than 90% with any chlorfenapyr application against Linognathus vituli (L.). However, percent reduction was greater than 90% with CyLence from day 21 through 35. No adverse effects were noted on cattle from any of the chlorfenapyr dosages used.