522 research outputs found
(E)-1,2-Bis(3-bromo-4-methylphenyl)ethene
In the structure of the title compound, C16H14Br2, the central C=C bond length is 1.329 (4) Å and the two benzene rings are approximately coplanar with the double bond, with twist angles of 7.5 (2) and 13.6 (2)°
IMPACTS OF SUPPLEMENTAL FEEDING ON THE NUTRITIONAL ECOLOGY OF BLACK BEARS
Black bear (Ursus americanus) damage to managed conifer stands during the spring in the U.S. Pacific Northwest is a continuing management concern. Because bear damage to managed conifers may reflect the limited availability of nutritious foods, supplemental feeding has been used to decrease damage. Highly palatable, pelleted feed is provided ad libitum from April until late June when berries ripen and such damage stops. We examined black bear use of supplemental feed during the spring and summer of 1998 and 1999 in western Washington. Bears were captured in areas where supplemental feed was provided and in control areas where no effort to reduce conifer damage occurred. Mass gains for bears captured twice were 153 ± 119 g/day (x̅± SD) in the fed areas and 12 ± 104 g/day in non-fed areas. Fat gain for bears in the fed areas was 42 ± 50 g/day and 4 ± 59 g/day in the non-fed areas. However, because age-specific body masses and fat content did not differ between the 2 areas, short-term pellet feeding probably has no long-lasting effect on bear condition or productivity. The diet of bears in the fed areas was 55 ± 22% pelleted feed, 7 ± 7% animal matter, and 38 ± 18% vegetation. The diet of bears in the non-fed areas was 13 ± 17% animal matter and 87 ± 17% vegetation. Grass and sedge composed the majority of vegetation consumed in both areas. The energy content of Douglas-fir (Pseudotsuga menziesii) and western hemlock ( Tsuga heterophylla) sapwood was more digestible (60-67%) than grasses and forbs (18-47%). Smaller bears (adult females and subadult males and females) may do most of the damage because sapwood harvesting rates minimize nutritional gain to larger adult males
Comparing attentional bias to smoking cues in current smokers, former smokers, and non-smokers using a dot-probe task
Much evidence documents that individuals with emotional and drug-use disorders demonstrate biased attention toward stimuli associated with their disorder. This bias appears to diminish following successful treatment. Two studies examined whether current cigarette smokers show biased attention toward smoking-related images compared with non-smokers (Studies 1 and 2) and whether this bias is less pronounced in former smokers (Study 2). Attentional bias toward cigarette-related photographs was examined using the dot-probe task. Pairs of images (one smoking-related) appeared side by side for 500 ms on a computer screen prior to the presentation of a probe (an asterisk) replacing one of the photographs. Subjects struck a key as quickly as possible to indicate the probe location. Attentional bias was defined as faster reaction times when the probe replaced the smoking-related image. In both studies, current smokers displayed significantly greater attentional bias toward cigarette stimuli than did non-smokers. Former smokers in Study 2 displayed an intermediate level of bias, but did not differ significantly in bias score from either of the other groups. These results support further use of the dot-probe task as a measure of attentional bias in non-abstinent smokers and in individuals undergoing smoking cessation treatment
Comparing the Psychometric Properties of Two Physical Activity Self-Efficacy Instruments in Urban, Adolescent Girls: Validity, Measurement Invariance, and Reliability
Aims: This study compared the psychometric properties of two self-efficacy instruments related to physical activity. Factorial validity, cross-group and longitudinal invariance, and composite reliability were examined.Methods: Secondary analysis was conducted on data from a group randomized controlled trial investigating the effect of a 17-week intervention on increasing moderate to vigorous physical activity among 5th–8th grade girls (N = 1,012). Participants completed a 6-item Physical Activity Self-Efficacy Scale (PASE) and a 7-item Self-Efficacy for Exercise Behaviors Scale (SEEB) at baseline and post-intervention. Confirmatory factor analyses for intervention and control groups were conducted with Mplus Version 7.4 using robust weighted least squares estimation. Model fit was evaluated with the chi-square index, comparative fit index, and root mean square error of approximation. Composite reliability for latent factors with ordinal indicators was computed from Mplus output using SAS 9.3.Results: Mean age of the girls was 12.2 years (SD = 0.96). One-third of the girls were obese. Girls represented a diverse sample with over 50% indicating black race and an additional 19% identifying as mixed or other race. Both instruments demonstrated configural invariance for simultaneous analysis of cross-group and longitudinal invariance based on alternative fit indices. However, simultaneous metric invariance was not met for the PASE or the SEEB instruments. Partial metric invariance for the simultaneous analysis was achieved for the PASE with one factor loading identified as non-invariant. Partial metric invariance was not met for the SEEB. Longitudinal scalar invariance was achieved for both instruments in the control group but not the intervention group. Composite reliability for the PASE ranged from 0.772 to 0.842. Reliability for the SEEB ranged from 0.719 to 0.800 indicating higher reliability for the PASE. Reliability was more stable over time in the control group for both instruments.Conclusions: Results suggest that the intervention influenced how girls responded to indicator items. Neither of the instruments achieved simultaneous metric invariance making it difficult to assess mean differences in PA self-efficacy between groups
Methane metabolism in the archaeal phylum Bathyarchaeota revealed by genome-centric metagenomics
Methanogenic and methanotrophic archaea play important roles in the global flux of methane. Culture-independent approaches are providing deeper insight into the diversity and evolution of methane-metabolizing microorganisms, but, until now, no compelling evidence has existed for methane metabolism in archaea outside the phylum Euryarchaeota. We performed metagenomic sequencing of a deep aquifer, recovering two near-complete genomes belonging to the archaeal phylum Bathyarchaeota (formerly known as the Miscellaneous Crenarchaeotal Group). These genomes contain divergent homologs of the genes necessary for methane metabolism, including those that encode the methyl–coenzyme M reductase (MCR) complex. Additional non-euryarchaeotal MCR-encoding genes identified in a range of environments suggest that unrecognized archaeal lineages may also contribute to global methane cycling. These findings indicate that methane metabolism arose before the last common ancestor of the Euryarchaeota and Bathyarchaeota
Approccio alla lingua italiana per allievi stranieri - ALIAS
Contiene, di P. E. Balboni,
- "Approccio alla lingua italiana per allievi stranieri", pp. 55-71
- "Problemi interculturali nei rapporti con allievi stranieri e con le loro famiglie", pp. 73-90
- "La fomrazione dei docenti: i contenuti e gli strumenti di base", pp. 181-184
Cyclophanes from kinetically stabilized bis(isobenzofuran)s
xxii, 122 leaves : ill. ; 29 cm.Isobenzofurans (IBF)s are interesting molecules with regards to their structure and reactivity. The properties of these compounds are investigated through the use of gas phase calculations and kinetic studies. This work provides insight into the aromatic character of IBF and how substituents affect IBF’s reactivity.
Substituted derivatives of naphtho[1,2-c:5,6-c]difuran are synthesized and reacted with tethered bis(dienophile)s to form cyclophanes. Phenyl-substituted naphtho[1,2-c5,6-c]difuran forms only a single isomer when reacted with a tethered bis(acrylate) and a tert-butyldimethylsilyl-substituted derivative exhibits higher selectivity towards cyclophane formation rather than polymer formation. Evidence for strong intramolecular interactions within these cyclophanes is presented as well.
A five-step synthesis of anthra[1,2-c:7,8-c]difuran is developed, although with a poor overall yield. Similar reaction conditions could be applied to the synthesis of anthra[1,2-c:5,6-c]difuran. We also propose the synthesis of two different aromatic belts from these compounds
- …