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251.
Adam Lanzarotta Ph.D. Michael D. Thatcher B.S. Lisa M. Lorenz B.S. JaCinta S. Batson M.S. 《Journal of forensic sciences》2020,65(5):1443-1449
A simple, quick, selective, sensitive, and effective field-friendly method capable of being used by nonexperts has been developed for detecting mitragynine in Mitragyna speciosa (kratom) using surface-enhanced Raman spectroscopy (SERS). Over 100 samples and blanks (known to be either positive or negative for the presence of mitragynine) were examined in duplicate using five identical handheld Raman spectrometers, which provided a data set of over 1,000 examinations. Based on the results of these analyses, the method yielded a true-positive rate of 99.3%, a true-negative rate of 97.9%, a false-positive rate of 2.1%, and a false-negative rate of 0.7%. The average minimum detectable concentration (Cm) of mitragynine that reproducibly yielded a match for one of the library spectra on all five instruments was determined to be 342 ng/mL (ppb). This Cm value is a conservative estimate considering that the extraction process was not fully optimized by this study, which was not necessary since the Cm value achieved was well below typical mitragynine concentrations in kratom (1.3–2.3%). The method is ideal (i) for prioritizing samples for additional testing using other more time-consuming laboratory-based techniques needed to detect and quantify mitragynine and (ii) for field use at international mail facility (IMF) satellite laboratories to help interdict kratom and prevent this dangerous product from reaching the U.S. supply chain. 相似文献
252.
Dominic Gascho R.T. Mária Marosi R.T. Michael J. Thali M.D. Eva Deininger-Czermak M.D. 《Journal of forensic sciences》2020,65(4):1360-1364
Postmortem magnetic resonance imaging (MRI) is rarely used for the radiologic assessment of gunshot injuries, although it has clear advantages over postmortem computed tomography (CT) with regard to the imaging of soft tissue injuries. Another benefit in using MRI is that lodged projectiles composed of nonferromagnetic material such as lead present only marginal metal artifacts compared with severe artifacts on CT. This case report presents CT and MRI findings in a case with two gunshot wounds to the neck: a perforating wound and a nonperforating wound with a lead bullet lodged in the cervical spine. The decedent underwent CT and MRI before the scheduled autopsy. A ring of radiopaque material under the dermis in the fatty tissue was identified at both entrance wounds on CT, which was indicative of contact shots. The perforating gunshot was clearly indicated on CT by bullet fragments along the wound channel through the perforated 6th cervical vertebra and the fractured cricoid cartilage at the exit wound. The second trajectory, however, was only assumed based on the presence of gunshot residues at the entrance wound and the position of the lodged bullet. The radiologic assessment was severely impeded by the metal artifacts on CT. Barely noticeable metal artifacts on MRI allowed for clear visualization of the soft tissue injuries and the ruptured medulla oblongata. Only MRI clarified the soft tissue injuries of the brainstem noninvasively, which could provide specific and graphic information on the rapidity of death and the incapacitation of the victim. 相似文献
253.
Paul Vedder John Berry Colette Sabatier David Sam 《Journal of youth and adolescence》2009,38(5):642-653
Correspondence in value orientation between parents and their offspring may be due to actual transmission processes between
generations, but it may also be due to influences from the general value context in society that are common to parents and
their offspring. This common value context is referred to as Zeitgeist. The present study deals with one family relationship
value (i.e., parents’ and adolescents’ obligations toward the family). Participants were 1,252 immigrant and 726 national
adolescent–parent dyads from 10 Western countries. There were significant relationships between the value placed on family
obligations among parents and offspring, and these were independent of gender. Zeitgeist effects, both intergenerational and
intragenerational, were found. The strength of these Zeitgeist effects depended on the basis for defining Zeitgeist, either
a person’s own ethnic group or the wider community including both nationals and immigrants. For explaining national adolescents’
acceptance of their family obligations, both the ethnic and the national Zeitgeist played a role, whereas in the immigrant
groups only the ethnic Zeitgeist played a significant role. In short, in an immigration context it makes sense to distinguish
the influence of a person’s own ethnic group from the influence of the wider community, including other ethnic groups. Explanations
are suggested and implications are discussed.
相似文献
Paul VedderEmail: |
254.
Easter Dawn Vo-Jutabha Khanh T. Dinh James P. McHale Jaan Valsiner 《Journal of youth and adolescence》2009,38(5):672-690
Focusing on identity development explorations enables a greater understanding of contexts that affect immigrant adolescents.
Utilizing thematic and grounded narrative analysis of 46 journal writings, during a one-month period, from first and second
generation Vietnamese adolescents ranging in age from 15 to 18 (26 residents of a culturally and politically active ethnic
enclave in Southern California; 20 adolescents living outside the enclave), this study establishes ways in which a focus on
social context and exploration processes illuminates the complexity of immigrant adolescents’ identity formation. The two
groups shared many similarities, including precipitants to exploration and steps undertaken to explore identity. However,
two factors—social and cultural influences and emotional reactions—revealed interesting contrasts distinguishing enclave from
non-enclave dwelling Vietnamese adolescents. Data also suggested that immigrant adolescents strive to integrate different
domains of identity (ethnicity, gender, career) both with one another and with the historical, social, and cultural contexts
they occupy.
相似文献
Jaan ValsinerEmail: |
255.
Children of immigrants who do translations and who interpret for others using their heritage language and English are known
as language brokers. Although prior research suggests that children of immigrants’ perceptions of the language brokering experience
vary greatly—from feeling a sense of efficacy to feeling a sense of burden—what remains unanswered in the literature is identification
of the antecedents and processes that help to explain the varying psychological experience of language brokers. Using data
from a two-wave prospective longitudinal study of 256 Chinese American adolescents, the present study tested potential mechanisms
that may be responsible for adolescents’ perceptions of the language brokering experience as a sense or burden or sense of
efficacy. The results demonstrate that adolescents’ Chinese orientation sets in motion a family process that is linked to
variations in the perceptions of adolescents’ language brokering experience. Adolescents who are more Chinese oriented have
a stronger sense of familial obligation, and these adolescents are more likely to perceive that they matter to their parents.
Adolescents’ perceived sense of mattering to parents, in turn, is associated positively with a sense efficacy, and negatively
with a sense of burden as language brokers. Those adolescents who are less Chinese oriented have a weaker sense of familial
obligation, and these adolescents are more likely to feel a sense of alienation from their parents. Adolescents’ sense of
perceived alienation from parents, in turn, is associated with a sense of burden as language brokers. Implications for developing
interventions for children who act as language brokers for their parents are discussed.
相似文献
Su Yeong Kim (Corresponding author)Email: Email: |
256.
This study examined the association between cigarette smoking and dieting behaviors and trends in that association among US
adolescents in grades 9–12 between 1999 and 2007. Youth Risk Behavior Survey datasets were analyzed using the multivariable
logistic regression method. The sample size of each survey year ranged from 13,554 to 15,273 with girls representing 49–51%
of the sample (N = 71,854). About 62% of the entire study participants were whites and 14% were blacks. Prevalence estimates of current smoking
and corresponding 95% confidence intervals were computed across four comparison groups formed by gender and body weight. Extreme
dieting was an independent predictor of smoking. Extreme dieters showed a higher variability of smoking behavior than their
peers. The magnitude of the association between smoking and extreme dieting became smaller in recent years among adolescents
but remained unchanged among non-overweight girls over that same time period. When adolescent smoking behavior is examined,
the intensity of dieting behavior should be considered within its association with other co-occurring unhealthy behaviors. 相似文献
257.
Willeke A. Manders Jan M. A. M. Janssens William L. Cook Johan H. L. Oud Eric E. J. De Bruyn Ron H. J. Scholte 《Journal of youth and adolescence》2009,38(10):1328-1338
Considerable research has focused on the reliability and validity of informant reports of family behavior, especially maternal
reports of adolescent problem behavior. None of these studies, however, has based their orientation on a theoretical model
of interpersonal perception. In this study we used the social relations model (SRM) to examine family members’ reports of
each others’ externalizing and internalizing problem behavior. Two parents and two adolescents in 69 families rated each others’
behavior within a round-robin design. SRM analysis showed that within-family perceptions of externalizing and internalizing
behaviors are consistently due to three sources of variance; perceiver, target, and family effects. A family/contextual effect
on informant reports of problem behavior has not been previously reported. 相似文献
258.
Depressive Symptoms and School Burnout During Adolescence: Evidence from Two Cross-lagged Longitudinal Studies 总被引:1,自引:0,他引:1
Katariina Salmela-Aro Hannu Savolainen Leena Holopainen 《Journal of youth and adolescence》2009,38(10):1316-1327
The main purpose of this study was to examine the extent to which middle and late adolescents’ depressive symptoms predict
their later school burnout and, in turn, the extent to which school burnout predicts depressive symptoms. Drawing on data
gathered at ages 15–19 in two-three-wave longitudinal studies, we investigated cross-lagged paths between school burnout and
depressive symptoms. In Study 1 the participants were 15-year-old adolescents (Time 1: N = 611, Time 2: N = 614, Time 3: N = 725) who completed the School Burnout Inventory and depressive symptoms twice during their final term of comprehensive
school and once after the transition to upper secondary high school or vocational school. In Study 2 the participants were
17-year-old adolescents whose school burnout and depressive symptoms were measured three times annually (Time 1: N = 474, Time 2: N = 412, Time 3: N = 414) during their 3 years of secondary education. Results of both studies revealed moderate stability for both school burnout
and depressive symptoms. They also showed that school burnout more strongly predicted subsequent depressive symptoms later
on than vice versa. Lastly, they revealed cumulative cycles between school burnout and depressive symptoms. 相似文献
259.
Roger J. R. Levesque 《Journal of youth and adolescence》2009,38(10):1281-1281
260.
Phillip L. Hammack Elisabeth Morgan Thompson Andrew Pilecki 《Journal of youth and adolescence》2009,38(7):867-883
Youth with same-sex desire undergo a process of narrative engagement as they construct configurations of identity that provide
meaning and coherence with available sexual taxonomies. This article presents a theoretical analysis and four case studies
centering on the relationship among context, desire, and identity for youth with same-sex desire. Through an interpretive,
holistic analysis of the personal narratives of youth, we examine the integration of same-sex desire, behavior, and identity
in the general life story and the selective appropriation of elements of “master narratives” of sexual identity development.
Narratives were characterized by challenges to integrate desire, behavior, and identity into a configuration that conformed
to the received sexual taxonomy. Implications for theory and further research on sexual identity development are discussed. 相似文献