Lunar Dust Levitation

Observations of a lunar “horizon glow” by several Surveyor spacecraft on the lunar surface in the 1960s and detections of dust particle impacts by the Apollo 17 Lunar Ejecta and Meteoroid Experiment have been explained as the result of micron-sized charged particles lifting off the surface. The surface of the Moon is exposed to the solar wind and solar UV radiation causing photoemission, so it develops a surface charge and an electric field near the surface. Dust particles injected into this plasma from the lunar regolith, whether from human and mechanical activity or from meteoroid impacts or electrostatic forces, may be stably levitated above the surface and may undergo preferential deposition onto areas of the lunar surface (or equipment) with different electrical properties. This can lead to a net transport as well as contamination of sensitive equipment. This paper reports on new experimental measurements and numerical simulations of the plasma environment above the lunar surface and the related behavior of charged dust.     

Protection from latent inhibition provided by a conditioned inhibitor.

Two conditioned suppression experiments with rats investigated the influence on latent inhibition of compounding a Pavlovian conditioned inhibitor with the target cue during preexposure treatment. Results were compared with those of subjects that received conventional latent inhibition training, no preexposure, or preexposure to the target cue in compound with a neutral stimulus. In Experiment 1, greater attenuation of the latent inhibition effect was observed in subjects that received target preexposure in compound with a Pavlovian conditioned inhibitor relative to subjects that received preexposure with a neutral stimulus or to the target alone. In Experiment 2, this protection from latent inhibition was attenuated if the excitor that was used to train the conditioned inhibitor was extinguished between preexposure and target training. The results are consistent with an account offered by the extended comparator hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fecal indicator bacteria are abundant in wet sand at freshwater beaches

Potential fecal contamination of sand in the wave-washed zone of public bathing beaches is overlooked in beach monitoring programs. Activity in this zone can bring pathogens to the sand surface or into the water, presenting a health risk to sensitive populations. On a unit weight basis (colony forming units per 100g), the mean summer abundance of the fecal indicator bacteria enterococci and Escherichia coli was 3-38 times higher in the top 20 cm of wet-sand cores than in the water column at six freshwater bathing beaches. E. coli were 4 times more abundant than enterococci in water but counts were similar in the sand. A correlation (r=0.60) existed between E. coli counts in the water and in the top 5 cm of sand only, whereas no relationship existed between enterococci abundance in water and sand. In general, enterococci were most numerous in the 5-10 cm sand stratum and E. coli in the 0-5 cm stratum. These preliminary data show that wet freshwater beach sand is a reservoir of fecal indicator bacteria. Enteric pathogens may also be present in beach sand.     

Dietary influences on terpenoids sequestered by the biological control agent Oxyops vitiosa: effect of plant volatiles from different Melaleuca quinquenervia chemotypes and laboratory host species

The weevil Oxyops vitiosa is an Australian species imported to Florida, USA, for the biological control of the invasive species Melaleuca quinquenervia. The larvae of this species feed on the leaves of their host and produce a shiny orange secretion that covers their integument. Previous results indicated that a major component of this secretion, viridiflorol, is sequestered from the host plant and repels a generalist predator, the red imported fire ant, Solenopsis invicta. When the larvae fed on a different chemotype of M. quinquenervia, which lacked viridiflorol but was rich in a different sesquiterpene, (E)-nerolidol, similar protection occurred. Solvent washes of these larvae indicated that (E)-nerolidol was sequestered from M. quinquenervia leaves and repelled S. invicta workers when applied to dog food baits at physiological concentrations (17.5, 35.0, and 52.5 g/mg). Additionally, -caryophyllene also repelled S. invicta workers when applied to dog food baits at concentrations that approximated those in the O. vitiosa larval secretions (3.5 and 35 g/mg). When the O. vitiosa larvae were fed leaves from laboratory hosts (nonfield hosts), similar repellent activity was found. This activity was traced to several of the same compounds (e.g., 1,8-cineole, viridiflorol) found to be active in their field host M. quinquenervia. These weevil larvae are opportunistic, sequestering the primary terpenoids in their host leaves that confer antipredator activity.     

Benefits of linear amplification and multichannel compression for speech comprehension in backgrounds with spectral and temporal dips

People with cochlear hearing loss have markedly higher speech-receptions thresholds (SRTs) than normal for speech presented in background sounds with spectral and/or temporal dips. This article examines the extent to which SRTs can be improved by linear amplification with appropriate frequency-response shaping, and by fast-acting wide-dynamic-range compression amplification with one, two, four, or eight channels. Eighteen elderly subjects with moderate to severe hearing loss were tested. SRTs for sentences were measured for four background sounds, presented at a nominal level (prior to amplification) of 65 dB SPL: (1) A single female talker, digitally filtered so that the long-term average spectrum matched that of the target speech; (2) a noise with the same average spectrum as the target speech, but with the temporal envelope of the single talker; (3) a noise with the same overall spectral shape as the target speech, but filtered so as to have 4 equivalent-rectangular-bandwidth (ERB) wide spectral notches at several frequencies; (4) a noise with both spectral and temporal dips obtained by applying the temporal envelope of a single talker to speech-shaped noise [as in (2)] and then filtering that noise [as in (3)]. Mean SRTs were 5-6 dB lower (better) in all of the conditions with amplification than for unaided listening. SRTs were significantly lower for the systems with one-, four-, and eight-channel compression than for linear amplification, although the benefit, averaged across subjects, was typically only 0.5 to 0.9 dB. The lowest mean SRT (-9.9 dB, expressed as a speech-to-background ratio) was obtained for noise (4) and the system with eight-channel compression. This is about 6 dB worse than for elderly subjects with near-normal hearing, when tested without amplification. It is concluded that amplification, and especially fast-acting compression amplification, can improve the ability to understand speech in background sounds with spectral and temporal dips, but it does not restore performance to normal.     

Correlation of angiography and MR imaging in cerebral vasculitis

Sixty primary untreated squamous cell carcinomas were studied for C-erbB2 gene amplification by non-fluorescence in situ hybridization technique. Amplified tumour cells showed intranuclear dark brown, often paired signals under light microscopy. Twenty-two out of 60 tumours (36.6%) showed signs of amplification of different degree (+ to +). Considerable heterogeneity of C-erbB2 amplification per cell was seen within each amplified tumour. The proportion of amplified cells ranged between 10 and 90% in these tumours. The arrangement of C-erbB2 in clusters in most amplified tumours suggests that C-erbB2 amplification occurs intrachromosomally. No significant difference in the frequency of amplification was observed according to clinical stage or the histological patterns of the tumours. The results of the present study showed frequent amplification of C-erbB2 in cervical carcinoma on paraffin sections. This technique was found to be more sensitive than the Southern blot technique which could detect amplification in 14% of the tumours of the same cohort.     

Efficacy of hypobromous acid as a hide-on carcass antimicrobial intervention

Escherichia coli O157:H7 and Salmonella on cattle hides at slaughter are the main source of beef carcass contamination by these foodborne pathogens during processing. Hypobromous acid (HOBr) has been approved for various applications in meat processing, but the efficacy of HOBr as a hide antimicrobial has not been determined. In this study, the antimicrobial properties of HOBr were determined by spraying cattle hides at either of two concentrations, 220 or 500 ppm. Treatment of hides with 220 ppm of HOBr reduced the prevalence of E. coli O157:H7 on hides from 25.3 to 10.1% (P < 0.05) and reduced the prevalence of Salmonella from 28.3 to 7.1% (P < 0.05). Treatment of hides with 500 ppm of HOBr reduced (P < 0.05) the prevalence of E. coli O157:H7 on hides from 21.2 to 10.1% and the prevalence of Salmonella from 33.3 to 8.1%. The application of 220 ppm of HOBr reduced (P < 0.05) aerobic plate counts, total coliform counts, and E. coli counts on hides by 2.2 log CFU/ 100 cm(2). The use of 500 ppm of HOBr resulted in reductions (P < 0.05) of aerobic plate counts, total coliform counts, and E. coli counts by 3.3, 3.7, and 3.8 log CFU/100 cm(2), respectively, demonstrating that the use of higher concentrations of HOBr on hides resulted in additional antimicrobial activity. These results indicate that the adoption of a HOBr hide wash will reduce hide concentrations of spoilage bacteria and pathogen prevalence, resulting in a lower risk of carcass contamination.     

Characteristics of veal calves upon arrival, at 28 and 84 days, and at end of the production cycle

Holstein bull calves arriving at five special-fed veal farms (eight production groups) were scored for various physical condition traits and blood-sampled within 2 h after arrival and at 28 d, 84 d, and 1 wk prior to slaughter at 116 to 143 d. Of 1179 total calves in the production groups, 758 calves were scored and evaluated. Blood cell analyses (red and white blood cell counts, hemoglobin, and packed cell volume) were conducted at all four sampling times; total serum protein concentration was obtained at 0 and 28 d. The study was initiated in autumn and ended the following autumn. Mean initial and final body weights were 46.3+/-0.17 and 209.7+/-0.77 kg; mean mortality was 2.5%. Average daily gain of the eight groups ranged from 1.23 to 1.70 kg/d. Subjective scores of 5 = excellent to 1 = very poor condition were used to evaluate 16 different physical condition characteristics. With the exception of leg joint, hoof, and foot scores, most of the physical condition scores exhibited improvement during the first 28 d. Foot and leg impairments did not appear to hinder the ambulatory ability of the calves during the production period. Physical condition scores at d 0 and 28 were generally not related to numbers or types of medical treatments (enteric, respiratory, other, or total) or to average daily gain during the production period. Means for most erythrocytic and leukocytic traits upon arrival (d 0) were within normal ranges, although 27.4% of the calves were clinically or marginally anemic. Final mean hemoglobin and packed cell volume were 8.53 g/dl and 26.1%. Forty-three percent of the calves at d 0 were colostral deficient, assuming that total serum protein concentrations of <5.5 g/dl indicate colostral deficiency. No blood trait was consistently correlated with body weight gain when gain during the production period was divided into quartiles and the blood traits were averaged by gain quartile. Calves in the lowest serum total protein quartile (mean 4.58 g/dl) had more respiratory and total medical treatments than quartiles with higher total protein means. Dairy bull calves arriving at veal production units after transporting from the dairy farm to the auction market (or other collection facility) have several physical impairments. However, most of these physical impairments are improved early in the veal feeding period and are not generally related to subsequent growth rate or medical treatment.