Abstract Purpose This study examines the association between bullying experiences and sexual violence (SV) perpetration among a sample of middle school students (n = 1391; males and females in grades ...5–8) across five middle schools in a Midwestern state. Methods We include waves 1 and 2 of a larger longitudinal study that aimed to track the overlap between bullying and SV victimization and/or perpetration across a 3-year period. Wave 1 data were collected in the spring of 2008, and wave 2 data were collected in the fall of 2008. Student participants completed a series of scales in a paper and pencil survey. After missing data imputation, a total sample of 1391 students was analyzed. Results Using cutoff scores, 12% of males and 12% of females could be considered bully perpetrators. Thirty-two percent of the boys (22% of girls) reported making sexual comments to other students, 5% of boys (7% of girls) spread a sexual rumor, and 4% of boys (2% of girls) pulled at someone's clothing. Bullying perpetration and homophobic teasing were significant predictors of sexual harassment perpetration over time. Conclusions Given the overlap among bullying, homophobic teasing perpetration, and SV perpetration, future studies should address the link among these forms of aggression so that prevention programs can be enhanced to address gender-based bullying and sexual harassment.
Display omitted
There are two types of DCP: dihydrated (brushite) and anhydrous (monetite). After implantation, brushite converts to hydroxyapatite (HA) which resorbs very slowly. This conversion is ...not observed after implantation of monetite cements and result in a greater of resorption. The precise mechanisms of resorption and degradation however of these ceramics remain uncertain. This study was designed to investigate the effect of: porosity, surface area and hydration on in vitro degradation and in vivo resorption of DCP. Brushite and two types of monetite cement based grafts (produced by wet and dry thermal conversion) were aged in phosphate buffered saline (PBS) and bovine serum solutions in vitro and were implanted subcutaneously in rats. Here we show that for high relative porosity grafts (50–65%), solubility and surface area does not play a significant role towards in vitro mass loss with disintegration and fragmentation being the main factors dictating mass loss. For grafts having lower relative porosity (35–45%), solubility plays a more crucial role in mass loss during in vitro ageing and in vivo resorption. Also, serum inhibited dissolution and the formation of HA in brushite cements. However, when aged in PBS, brushite undergoes phase conversion to a mixture of octacalcium phosphate (OCP) and HA. This phase conversion was not observed for monetite upon ageing (in both serum and PBS) or in subcutaneous implantation. This study provides greater understanding of the degradation and resorption process of DCP based grafts, allowing us to prepare bone replacement materials with more predictable resorption profiles.
Batch culture of biofilms on peg lids is a versatile method that can be used for microtiter determinations of biofilm antimicrobial susceptibility. In this paper, we describe a core protocol and a ...set of parameters (surface composition, the rate of rocking or orbital motion, temperature, cultivation time, inoculum size, atmospheric gases and nutritional medium) that can be adjusted to grow single- or multispecies biofilms on peg surfaces. Mature biofilms formed on peg lids can then be fitted into microtiter plates containing test agents. After a suitable exposure time, biofilm cells are disrupted into a recovery medium using sonication. Microbicidal endpoints can be determined qualitatively using optical density measurements or quantitatively using viable cell counting. Once equipment is calibrated and growth conditions are at an optimum, the procedure requires approximately 5 h of work over 4-6 d. This efficient method allows antimicrobial agents and exposure conditions to be tested against biofilms on a high-throughput scale.
Parturition is a painful event experienced by cows at the onset of lactation. This pain could lead to a reduced feed intake, altered metabolic and immunological status, and a host of other diseases ...that could seriously limit her productive herd lifespan. The objective of the current study was to assess the effect of administration of a single dose of oral meloxicam, a non-steroidal anti-inflammatory drug (NSAID), on the production and health status of cows during their lactation. A total of 2,653 (1,009 meloxicam-treated and 1,644 untreated control) cows were enrolled across 20 herds in the provinces of Ontario and Quebec, Canada. Relative to untreated controls, meloxicam-treated cows produced 0.64 kg/day (SE = 0.29. P = 0.03) more milk over the first 3 test days (90-120 days in lactation), had 0.75 times the odds of subclinical mastitis at first test (SE = 0.08, P = 0.01), and were culled or died at 0.46 times the rate (SE = 0.16, P = 0.03) before 60 days in milk. These results are consistent with previous research and lend support to the hypothesis that parturition is a painful event in cattle. Attempts to ameliorate such pain with analgesics is associated with a variety of positive health and production outcomes.
Bullying perpetration and sexual harassment perpetration among adolescents are major public health issues. However, few studies have addressed the empirical link between being a perpetrator of ...bullying and subsequent sexual harassment perpetration among early adolescents in the literature. Homophobic teasing has been shown to be common among middle school youth and was tested as a moderator of the link between bullying and sexual harassment perpetration in this 2-year longitudinal study. More specifically, the present study tests the Bully–Sexual Violence Pathway theory, which posits that adolescent bullies who also participate in homophobic name-calling toward peers are more likely to perpetrate sexual harassment over time. Findings from logistical regression analyses (n = 979, 5th-7th graders) reveal an association between bullying in early middle school and sexual harassment in later middle school, and results support the Bully–Sexual Violence Pathway model, with homophobic teasing as a moderator, for boys only. Results suggest that to prevent bully perpetration and its later association with sexual harassment perpetration, prevention programs should address the use of homophobic epithets.
Constraining the duration of magmatic activity on the Moon is essential to understand how the lunar mantle evolved chemically through time. Determining age and initial isotopic compositions of mafic ...lunar meteorites is a critical step in defining the periods of magmatic activity that occurred during the history of the Moon and to constrain the chemical characteristics of mantle components involved in the sources of the magmas. We have used the in situ Pb‐Pb SIMS technique to investigate eight lunar gabbros and basalts, including six meteorites from the Northwest Africa (NWA) 773 clan (NWA 2727, NWA 2700, NWA 3333, NWA 2977, NWA 773, and NWA 3170), NWA 4734, and Dhofar 287A. These samples have been selected as there is no clear agreement on their age and they are all from the dominant low titanium chemical group. We have obtained ages of 2981 ± 12 Ma for NWA 4734 and 3208 ± 22 Ma for Dhofar 287. For the NWA 773 clan, four samples (the fine‐grained basalt NWA 2727 and the three gabbros NWA 773, NWA 2977, NWA 3170) out of six yielded isochron‐calculated ages that are identical within uncertainties and yielding an average age of 3086 ± 5 Ma. The age obtained for the fine‐grained basalt NWA 2700 is not precise enough for comparison with the other samples. The gabbroic sample NWA 3333 yielded an age of 3038 ± 20 Ma suggesting that two distinct magmatic events may be recorded in the meteorites of the NWA 773 clan. The present study aims to identify and assess all potential issues that are associated with different ways to date lunar rocks using U‐Pb–based methods. To achieve this, we have compared the new ages with the previously published data set. The entire age data set from lunar mafic meteorites was also screened to identify data showing analytical issues and evidence of resetting and terrestrial contamination. The data set combining the ages of mafic lunar meteorites and Apollo rocks suggests pulses of magmatic activity with two distinct phases between 3950 and 3575 Ma and between 3375 and 3075 Ma with the two phases separated by a gap of approximately 200 Ma. The evolution of the Pb initial ratios of the low‐Ti mare basalts between approximately 3400 and 3100 Ma suggests that these rocks were progressively contaminated by a KREEP‐like component.
The age assigned to the boundary of the Barremian and Aptian stages remains one of the most poorly constrained post-Pangean stratigraphic boundaries. The lack of a Global Boundary Stratotype Section ...and Point (GSSP) for the stage boundary has hampered efforts to calibrate the absolute age of the Cretaceous period in the geological time scale. The current definition of the Barremian–Aptian boundary also approximates the onset of magnetic polarity chron M0r; the end of this chron denotes the start of the Cretaceous Normal polarity Superchron that is of fundamental importance for plate reconstructions. Currently, there is up to 5% discrepancy in the age estimates of the Barremian–Aptian boundary (ca. 126–121 Ma) and the start of the Cretaceous Normal Superchron. Here, we review available geochronological information from the late Barremian and early Aptian stages collected from the Pacific Ocean, China, California, the Ontong Java Nui large igneous province and the High Arctic large igneous province. By utilizing only robust geochronological data including U-Pb and recalibrated 40Ar/39Ar ages from sites with magnetic polarity information and/or paleontological constraints, we calculate a best estimate of between 123.8 and 121.8 Ma for the Barremian–Aptian boundary and the onset of chron M0r at 2σ confidence. Using estimates of the duration of chron M0r (0.49 ± 0.10 Myr, 2σ), we conservatively compute the start of the Cretaceous Normal Superchron to between 123.4 and 121.2 Ma (2σ). Using an age of 83.07 ± 0.15 Ma (2σ) for the end of the Cretaceous Normal Superchron, the duration of the superchron is also constrained to between 38.0 and 40.5 Myr (2σ). These age ranges for the Barremian–Aptian boundary, the onset of the Cretaceous Normal Superchron and the duration of the superchron currently provide the best estimates until a GSSP is formally ratified.
PDF
