1,963 research outputs found
Reactions forming C(0,+)n=2,10, Cn=2,4H(0,+) and C3H(0,+) in the gas phase: semi empirical branching ratios
The aim of this paper is to provide a new set of branching ratios for
interstellar and planetary chemical networks based on a semi empirical model.
We applied, instead of zero order theory (i.e. only the most exoergic decaying
channel is considered), a statistical microcanonical model based on the
construction of breakdown curves and using experimental high velocity collision
branching ratios for their parametriza- tion. We applied the model to
ion-molecule, neutral-neutral, and ion-pair reactions implemented in the few
popular databases for astrochemistry such as KIDA, OSU and UMIST. We studied
the reactions of carbon and hydrocarbon species with electrons, He+, H+, CH+,
CH, C, and C+ leading to intermediate complexes of the type Cn=2,10, Cn=2,4 H,
C3 H2, C+n=2,10, Cn=2,4 H+, or C3 H+2 . Comparison of predictions with
measurements supports the validity of the model. Huge deviations with respect
to database values are often obtained. Effects of the new branching ratios in
time dependant chemistry for dark clouds and for photodissociation region
chemistry with conditions similar to those found in the Horsehead Nebula are
discussed
Alien Registration- Chabot, Marie A. (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29375/thumbnail.jp
Alien Registration- Chabot, Joseph A. (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29373/thumbnail.jp
A Believer and a Skeptic Agree in a Postmodern World
Through distinct personal narratives we will compare our religious discoveries from childhood to the present day. We will explain spirituality as a pivotal part of our self-realization throughout college and our initial inspiration to search for our respective higher beings. We attempt to explain our drastically different religious and spiritual backgrounds while also presenting parallels that allow us to find a common understanding of faith
Erratum aux « RĂ©sumĂ©s des communications scientifiques prĂ©sentĂ©es lors du 17e CongrĂšs de pneumologie de langue française. 1â3 fĂ©vrier 2013 (Lille, France) » [Rev. Mal. Respir. 30 (2013) A1âA192]
Patterns of Activity Expressed by Juvenile Horseshoe Crabs
Adult American horseshoe crabs, Limulus polyphemus, possess endogenous circadian and circatidal clocks controlling visual sensitivity and locomotion, respectively. The goal of this study was to determine the types of activity rhythms expressed by juvenile horseshoe crabs (n = 24) when exposed to a 14:10 light/dark cycle (LD) for 10 days, followed by 10 days of constant darkness (DD). Horseshoe crab activity was recorded with a digital time-lapse video system that used an infrared-sensitive camera so animals could be monitored at night. In LD, 15 animals expressed daily patterns of activity, 6 displayed a circatidal pattern, and the remaining 3 were arrhythmic. Of the 15 animals with daily patterns of locomotion, 7 had a significant preference (P \u3c 0.05) for diurnal activity and 3 for nocturnal activity; the remainder did not express a significant preference for day or night activity. In DD, 13 horseshoe crabs expressed circatidal rhythms and 8 maintained a pattern of about 24 h. Although these results suggest the presence of a circadian clock influencing circatidal patterns of locomotion, these apparent circadian rhythms may actually represent the expression of just one of the two bouts of activity driven by the putative circalunidian clocks that control their tidal rhythms. Overall, these results indicate that, like adults, juvenile horseshoe crabs express both daily and tidal patterns of activity and that at least one, and maybe both, of these patterns is driven by endogenous clocks
Multi-Regression Prediction of Metal Partition Coefficients under Various Physical/Chemical Conditions Design of Experiments As, Cr, Cu, Ni and Zn
The behavior of metals in surface water is complex and their partition coefficients can be impacted by many factors. Organic matter (OM) content in sediments, pH and salinity, are factors that may influence speciation and partitioning of metals. The difficulty in describing the impacts and relationships are that these processes are interconnected with no dominant associations among all. In this study, the partitioning of five metals (As, Cr, Cu, Ni and Zn) under different levels of salinity, pH, and OM content were investigated. A series of factorial design experiments are evaluated in which three levels of OM are tested each time against five levels each of salinity and pH; the design of experiments was generated by the statistical software program MiniTab16Âź. All metals tested showed a trend of increasing Kd with the increase of OM 0.36% to 4.32%. Higher Kd were the result of the increase in pH from 3-10.5 and lower Kd values resulted after an increase in salinity 0-3%. However, within that lower range of salinity, a positive linear correlation between Kd and salinity was observed which is attributed to potential formation of insoluble metal species with the increase of salinity. Multiple regression equations with the variables pH, OM and salinity were generated to predict Kd of each metal. The study showed no interaction between salinity/OM and pH/OM for all five metals
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Young parentsâ experiences and perceptions of âTeen Momâ reality shows
MTVâs hit reality shows 16 and Pregnant and Teen Mom were produced with an agenda of preventing teen pregnancy. Researchers have examined their effectiveness as behavioral interventions, yet little attention has been paid to experiences of young parents themselves with these shows, nor to their ethical consequences, including the potential for compounding of stigma against young parents. This analysis qualitatively examines the experiences of young parents in British Columbia, Canada, with the media phenomenon referred to as âTeen Mom shows.â Interview and observation data from a large, longitudinal, mixed-methods ethnographic study of young parents was analyzed using hybrid deductive-inductive qualitative content analysis. The dominant understanding was that Teen Mom depictions of young parenting were inaccurate and overly dramatic. Young mothers and fathers experienced stigma and judgement that directly or indirectly referred to Teen Mom portrayals of young mothers as immature, dramatic, and promiscuous, and young fathers as absentee parents
Prediction of Metal Remobilization from Sediments under Various Physical/ Chemical Conditions âDesign of Experiments Cd, Co and Pbâ
The metal partition coefficient Kd (L/kg) is the ratio of sorbed metal concentration on the solid phase m (mg/kg) to the dissolved metal concentration at equilibrium. The behavior of metals in surface water is complex and their partition coefficients can be impacted by many factors. Organic matter (OM) content in sediments, pH and salinity, are factors that may influence speciation and partitioning of metals. In this study, the partitioning coefficient of three metals (Cd, Co and Pb) under different levels of salinity, pH, and OM content were examined. A series of factorial experiments were evaluated in which three levels of OM are tested each time against five levels each of salinity and pH; the design of experiments was generated by the statistical software program, MiniTab16Âź. All metals tested showed a trend of increasing Kd with an increase of OM from 0.36% to 4.36%. Salinity experiments showed that the lower values of Kd were all recorded in freshwater and the highest Kd values were recorded in saltwater. The metal Pb showed the highest Kd values. The average Kd values under acidic conditions for Cd, Co and Pb are 234, 83 and 5,618 L/kg respectively. The relatively higher value of Kd for Pb compared to that of Cd and Co can be attributed to its lower precipitating pH. Multiple regression equations were generated to predict Kd of each metal when comparing multiple factors at the same time (salinity/OM and pH/OM). The study showed no significant interactions between salinity/OM and pH/ OM for all three metals. This supports that tested factors are all affected Kd but act independently
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