共查询到20条相似文献,搜索用时 15 毫秒
1.
Christopher M. Napolitano Edmond P. Bowers Miriam R. Arbeit Paul Chase G. John Geldhof Jacqueline V. Lerner 《应用发育科学》2013,17(1):46-58
Mentoring programs may be contexts for building important intentional self-regulatory skills in adolescents. In this study, we provide data about the factor structure of new measures that assess youth intentional self-regulation (ISR) within such programs: the “GPS growth grids.” Using data from 409 mentor/youth dyads from 24 programs around the United States, we assess whether the resulting factor structure can be invariantly measured across mentor and mentee raters and three times of measurement. Results indicated that a single-factor structure best fit older and younger mentee age groups’ data. Older mentee and mentor data displayed measurement invariance across time and rater, while younger mentee and mentor data displayed invariance across time. Results also indicated differences in the factor correlations, means, and variances across rater and age group. These findings support using these measures for future longitudinal work assessing the role of youth, mentor, and program characteristics in promoting youth ISR skills. 相似文献
2.
The redox-active tyrosine YD (D2-Tyr160) in photosystem II (PSII) serves as a side-path electron donor to P680. When YD is oxidized, a proton is released from phenolic OH, and a neutral radical YD* is formed. A hydrogen bond network around YD must be deeply involved in the mechanism of the YD reaction. In this study, we have detected water molecules structurally coupled to YD by means of Fourier transform infrared (FTIR) spectroscopy. Light-induced YD*/YD FTIR difference spectrum of a hydrated film of the PSII core complexes from Thermosynechococcus elongatus showed major signals at 3636(-)/3617(+) and 3594(+)/3585(-) cm-1 in the weakly hydrogen bonded OH stretching region. These peaks downshifted by 11-12 cm-1 upon H218O substitution and almost disappeared upon H/D exchange, and hence, they were definitely assigned to the water OH vibrations. Small intramolecular couplings of 3-6 cm-1 estimated from the OH frequencies of residual HOD species in a deuterated film indicate that these OH signals arise from two different water molecules that have significantly asymmetric hydrogen bond structures. Similar OH signals were observed in PSII-enriched membranes from spinach, suggesting that two water molecules commonly exist near YD irrespective of biological species. These water molecules are coupled to YD most probably through a hydrogen bond network or one of them possibly interacts directly with YD, and thus, they may play crucial roles in the YD reaction by forming a proton-transfer pathway and tuning the redox potential of YD. 相似文献
3.
AbstractYouth participation in sport is associated with positive developmental outcomes. The development of life skills is especially important for urban youth of color who are often underserved and face poor long-term outcomes. To service the needs of underserved youth, community youth sport programs have begun to utilize sport-based positive youth development (PYD). Through this approach, key adult figures such as sport program staff and parents/caregivers have been identified as important mechanisms for life skill development and the transfer of learning. The aim of the current study sought to better understand how key adult figures influence life skill outcomes of urban youth of color involved in a community sport-based PYD program. Hierarchical linear regression analyses were used to examine the independent and interactive effects of staff support and parent/caregiver support on youth life skill and transfer of learning outcomes. Results indicated that staff support and parent/caregiver support predicted youth life skill and transfer of learning outcomes, both independently and, in some cases, interactively. 相似文献
4.
Denise Montgomery 《Arts Education Policy Review》2017,118(1):1-18
ABSTRACTCreative youth development (CYD) is a dynamic area of community arts education that successfully bridges youth development and arts education. CYD is an intentional, holistic practice that combines hands-on artmaking and skill building in the arts with development of life skills to support young people in successfully participating in adolescence and navigating into adulthood. Young people in CYD programs exhibit high levels of artistic skill and accomplishment along with increased self-esteem and sense of belonging. CYD participants are immersed in a broad array of rigorous artistic endeavors, including creating documentary films, researching and reporting on community issues through radio broadcasts, writing and staging new theatrical works, and engaging in thoughtful critique of one another's visual art work. The impact for youth of program participation extends beyond pride in artistic accomplishment. Throughout the United States, teen participants in CYD programs assert that the programs saved their lives, putting them on positive trajectories and away from gangs, drug use, crime, and ennui. This article provides a definition for the term creative youth development, describes core characteristics of CYD programs, and briefly describes four CYD programs. It provides background on the origins and history of creative youth development, including current advances in the field and signs the field is coalescing. The article describes creative youth development in the larger contexts of arts education and of education reform. Lastly, the article discusses policy, funding, and research needs and opportunities and provides questions for consideration. 相似文献
5.
The basal diameter of the annual shoot (1YD) affects vegetative growth and fruiting of the walnut trees. In order to determine interdependency between the 1YD and the older parent wood, 64 walnut genotypes belonging to four different branching and fruiting habits (morphotypes M-I, M-II, M-III and M-IV) were investigated. Year-to-year stability of 1YD was tested with the architectural analysis of a 3-year-old fruiting branch and its constituents (a 3-year-old bearer + corresponding 2-year-old + annual shoots) during 3 successive years. Based on Pearson's correlation coefficients and the multiple regression analysis of 12 quantitative traits, 12 models (four morphotype in 3 successive years) of 1YD were formed. They were compared with the standard model which was calculated on the basis of 1-year measurements of 1Y with no respect to the branching and fruiting type and comprises three quantitative traits, i.e. basal diameter of a 2-year-old parent shoot (2YD), the length of 2Y shoot (2YL), and the length of annual shoot (1YL). In a single year, the 1YD was influenced by two–five parameters. Five out of 12 models agreed with the standard model: in the lateral fruiting genotypes (M-IV), 1YD was always under the influence of the 2Y diameter, and the 1Y length. In addition, the number of nodes of the 2Y parent shoot had an important influence on 1Y diameter. In the terminal bearers (M-I), the impact of 2YD on the 1YD slightly increased with the tree age, and some other parameters, like 1Ynumber and 1Ynodes, which became to be important for 1YD. In the intermediate genotypes with mezotonic ramification (M-II), the number of vegetative buds per 1Y and angles of 1Y had significant effects on 1YD. In the intermediate bearers with acrotonic ramification (M-III), one to four other parameters were included into the model each year beside the 1Y number. Since the traits of a 2-year-old parent shoot have a great influence on the 1YD, the information from the year N can be used for the prediction of the annual shoot development in the year N+1. Such a prediction is more reliable in M-I and M-IV than in M-II and M-III. When we deal with the intermediate fruiting cultivars, 1Y number has to be considered in prediction of 1Y diameter beside 2YD and 1YL. 相似文献
6.
Nicole Zarrett Michelle Abraczinskas Brittany Skiles Cook Dawn K. Wilson Faten Ragaban 《应用发育科学》2018,22(1):58-73
Afterschool programs (ASPs) have become increasingly recognized as a key context to support youth daily physical activity (PA) accrual. Using Self-Determination Theory (SDT) as a framework, this study examined staff perspectives on the strengths and barriers within under-resourced ASPs for establishing a social-motivational climate for encouraging and supporting youth PA. Analysis of semi-structured staff interviews (28 staff; 7 ASPs) indicated that staff had knowledge and value for establishing a PA-supportive motivational climate. However, the feasibility of implementing PA curricula was identified as challenging across programs. Findings suggest increased need for staff training and supports to provide a PA climate that meets the developmental needs/interests of all youth, with particular attention toward increasing the PA of girls and older program youth. Furthermore, striking an appropriate balance between PA and other competing program demands (e.g., academics) will be required to optimize on the effectiveness of PA program components. 相似文献
7.
8.
Atle Nesje Jostein Bakke Stephen J. Brooks Darrell S. Kaufman Emma Kihlberg Mathias Trachsel William J. D’Andrea John A. Matthews 《Vegetation History and Archaeobotany》2014,23(3):229-248
Late Glacial and Holocene environmental changes were reconstructed using physical, chemical and biological proxies in Lake Myklevatnet, Allmenningen, (5º13′17″E, 61º55′13″N) located at the northern side of Nordfjorden at the coast of western Norway. Myklevatnet (123 m a.s.l.) lies above the Late Glacial marine limit and contains sediments back to approximately 14,300 years before a.d. 2000 (b2k). Because the lake is located ~48 km beyond the margin of the Younger Dryas (YD) fjord and valley glaciers further inland, and did not receive glacier meltwater from local glaciers during the YD, the lake record provides supplementary information to Lake Kråkenes that received glacial meltwater from a local YD glacier. Lake Myklevatnet has a small catchment and is sensitive to Late Glacial and Holocene climate and environmental changes in the coastal region of western Norway. The age-depth relationship was inferred from a radiocarbon- and tephra-based smoothing-spline model with correlated ages from oxygen isotope maxima and minima in the Late Glacial sequence of the NGRIP ice core (in years b2k) to refine the basal chronology in the Myklevatnet record. The results indicate a two-step YD warming, colder early YD temperatures than in the later part of the YD, and considerably more climate and environmental variability during the late Holocene in western Norway than recorded previously in the oxygen isotopes from Greenland ice cores. The Myklevatnet record is also compared with other Late Glacial and Holocene terrestrial and marine proxy reconstructions in the North Atlantic realm. 相似文献
9.
Early identification of anxiety among youth is required to prevent them from going unrecognised and untreated by mental health professionals. A precise identification of the young person's primary difficulty is also required to guide treatment programs. Availability of a valid and easily administrable assessment tool is crucial for identifying youth suffering from anxiety disorders. The purpose of the present study was therefore to examine the psychometric properties of the Danish version of the Revised Children's Anxiety and Depression Scale (RCADS). A total of 667 youth from community schools (4(th) through 9(th) grade) across Denmark participated in the study. The psychometric properties of the RCADS-(DAN) resembled those reported in US and Europe. Within scale reliability was excellent with Chronbach's alpha of.96. All subscales also showed good to excellent internal reliability. The study provides convincing evidence that the RCADS-(DAN) is a valid assessment tool for screening anxiety in Danish youth. 相似文献
10.
Although assigned mentoring relationships have typically involved same-gender matches, a growing number of programs, particularly those in schools, have begun pairing female mentors with male mentees. This practice stems, in large part, from the relative dearth of male mentors and programs’ efforts to increase the availability of youth mentoring to young males on waiting lists. We drew on secondary data from the two largest random assignment evaluations of school-based mentoring programs, the Department of Education's Student Mentoring Program and Big Brothers Big Sisters of America's School-based Mentoring, to explore the characteristics and effects of same- versus cross-gender mentoring relationships for male mentees. Our sample included 1,513 male youth from the respective programs. With only a few exceptions, male youth in same- versus cross-gender mentoring relationships experienced similar relationship processes and outcomes. Implications for research and practice are discussed along with limitations including the nonexperimental design of the study and unmeasured effects of selection bias. 相似文献
11.
pH-dependent charge equilibria between tyrosine-D and the S states in photosystem II. Estimation of relative midpoint redox potentials 总被引:5,自引:0,他引:5
The effect of protonation events on the charge equilibrium between tyrosine-D and the water-oxidizing complex in photosystem II has been studied by time-resolved measurements of the EPR signal IIslow at room temperature. The flash-induced oxidation of YD by the water-oxidizing complex in the S2 state is a monophasic process above pH 6.5 and biphasic at lower pHs, showing a slow and a fast phase. The half-time of the slow phase increases from about 1 s at pH 8.0 to about 20 s at pH 5.0, whereas the half-time of the fast phase is pH independent (0.4-1 s). The dark reduction of YD+ was followed by measuring the decay of signal IIslow at room temperature. YD+ decays in a biphasic way on the tens of minutes to hours time scale. The minutes phase is due to the electron transfer to YD+ from the S0 state of the water-oxidizing complex. The half-time of this process increases from about 5 min at pH 8.0 to 40 min at pH 4.5. The hours phase of YD+ has a constant half-time of about 500 min between pH 4.7 and 7.2, which abruptly decreases above pH 7.2 and below pH 4.7. This phase reflects the reduction of YD+ either from the medium or by an unidentified redox component of PSII in those centers that are in the S1 state. The titration curve of the half-times for the oxidation of YD reveals a proton binding with a pK around 7.3-7.5 that retards the electron transfer from YD to the water-oxidizing complex. We propose that this monoprotic event reflects the protonation of an amino acid residue, probably histidine-190 on the D2 protein, to which YD is hydrogen bonded. The titration curves for the oxidation of YD and for the reduction of YD+ show a second proton binding with pK approximately 5.8-6.0 that accelerates the electron transfer from YD to the water-oxidizing complex and retards the process in the opposite direction. This protonation most probably affects the water-oxidizing complex. From the measured kinetic parameters, the lowest limits for the equilibrium constants between the S0YD+ and the S1YD as well as between the S1YD+ and S2YD states were estimated to be 5 and 750-1000, respectively.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
12.
《应用发育科学》2013,17(4):200-214
This article describes a developmental systems approach to applied developmental science (ADS), which provides a framework to design and evaluate technology-rich programs that promote positive development by emphasizing the strengths and assets of young people instead of focusing on diminishing or preventing risk-taking behaviors. Until now, most of the psychoeducational programs conceived within the ADS model have not focused on the role of new technologies in young people's lives. This absence is particularly striking given that, in today's world, new technologies play an important role in different areas of the lives of young people, such as education, entertainment, socialization, and communication. This article presents the concept of identity construction environments (ICE), an interdisciplinary model that proposes guidelines to design and study new technologies purposefully created to promote positive youth development (PYD). Two types of ICE have been developed: one focusing on stand-alone technologies for learning, such as the Zora virtual city; and the other focusing on an approach for developing technologically rich learning contexts, such as the Project Inter-Actions robotics workshops. This article presents both examples of ICE and describes how their design fosters the 6 components of PYD. Initial findings from pilot studies conducted with very different populations of youth engaged in both types of ICE—such as young children, adolescents, and chronically ill children—are presented. 相似文献
13.
Addressing male sexual behavior and condom use is a high priority for adolescent health programs. Using the 1997 Ghana Psychographic Survey, the aim of this study is to explore the factors related to current, partner-specific condom use, by Ghanaian males aged 15-24 years. A multivariate regression analysis reveals an independent association between psychographic attitudes, peer network characteristics, sexual partner characteristics, and some level of condom use with a nominated sexual partner. The most important predictor for both condom use consistently as well as condom use at least sometimes was respondents' knowing someone who died as a result of AIDS. This finding suggests that future interventions should aim to personalize the risk of HIV/STIs, promote condom use with a range of partner types, and educate youth about the importance of consistent use. 相似文献
14.
First Nations, Métis, and Inuit (FNMI) youth experience many health disparities in comparison with their mainstream Canadian peers. Researchers have recommended that interventions developed to enhance health and well-being for FNMI youth apply a strengths-based approach that acknowledges contextual challenges. This article uses a qualitative approach to examine the perceived impacts of a program designed to enhance positive development and leadership in FNMI youth. Semistructured interviews were conducted with front-line staff and participants. A thematic data analysis resulted in three major themes that describe the perceived program effects at the participant, staff, and community levels. Findings are discussed in relation to current research and theory, and recommendations are provided for programming and future research. Leadership programming for FNMI youth may be an effective way to promote development across many levels of stakeholders. 相似文献
15.
Cross-age peer mentoring programs, in which teenagers mentor younger children, have proliferated in recent years, yet there is disagreement about the effectiveness of such programs. This study tested whether teen mentors' attitudes about children interact with their mentees' characteristics to moderate outcomes of cross-age peer mentoring. The sample included 221 high school volunteers, 205 mentees, and 182 control group youth. Latent profile analyses yielded two profiles of students who were labeled “academically connected” or “disconnected.” Analyses revealed that the academically disconnected mentees who were paired with mentors holding relatively positive attitudes toward youth were more emotionally engaged in the mentoring relationship (than disconnected mentees with more negative mentors) and, subsequently, reported stronger relationships with their teachers at year's end (than did the similarly disconnected children in the control group). Conversely, there was evidence of iatrogenic effects of matching negative mentors with academically connected mentees. Implications for mentor selection and training are discussed. 相似文献
16.
大田增温对夏玉米光合特性的影响 总被引:18,自引:0,他引:18
在大田条件下研究了增温对两个夏玉米品种农大108(ND108)和掖单13号(YD13)光合特性及产量的影响.结果表明:大喇叭口期到成熟期增温显著降低了夏玉米籽粒产量,ND108和YD13的籽粒产量分别较对照降低了46.6%和45.1%;叶面积指数平均值分别降低了15.4%和11.5%;穗位叶叶片光合速率平均值分别降低了22.85%和18.14%;两个玉米品种叶片的叶绿素a和叶绿素b含量显著降低,但对叶绿素a的影响更显著.增温后玉米叶片的磷酸烯醇式丙酮酸羧化酶(PEPCase)和核酮糖二磷酸羧化酶(RuBPCase)活性都显著降低,ND108、YD13叶片的PEPCase和RuBPCase活性分别较对照降低了51.1%、32.4%和29.5%、7.7%. 相似文献
17.
There is a widespread belief that youth drop out of youth development programs during the middle school years. Alternative explanations for the smaller number of adolescent program participants have yet to be explored. We examine age trends in program enrollment using data from over 221,000 youth enrolled in the California 4-H Youth Development Program from 1992 to 2002. We include sex, race/ethnicity, rural/urban residence, and project participation as predictors of dropout. Our results indicate that the peak in enrollment in early adolescence that is observable from annual enrollment data can be accounted for by stable and high enrollment turnover before age 11, followed by increased program dropout and fewer new enrollments. These findings have implications for explanations of youth program participation and for youth development program enrollment strategies, both for the 4-H Youth Development program and for youth programs in general. 相似文献
18.
Emma Strother 《Arts Education Policy Review》2019,120(1):1-10
An expansive movement comprised of UN Millennium Development Goals, international banks, and hundreds of programs worldwide promotes access to the arts as a creative means of social change. Often grounded in cognitive science and inspired by the model of youth orchestras in Venezuela known as El Sistema, this movement contends that arts training—which can foster empathy, collaboration, academic achievement, and self-esteem—helps alleviate poverty and combat inequality. In contrast to the majority of the literature on public arts programs—impact studies that often assume arts engagement creates social change through universal mechanisms—this study examines the influence of political economy on the implementation of public arts programs. Through a comparative study of youth orchestras with social inclusion goals in Venezuela (1974–2015) and Chile (1964–2015), the scope and intensity of government control, social welfare policy, and competition for public funds are found to shape public arts programs' social goals, daily operations, definitions of success, and impact study procedures. Therefore, scholars, practitioners, and policy makers must reexamine their understanding of arts programs as a development model. Future global efforts to combat inequality should avoid over-standardization. This article offers a new Arts for Social Change Context Framework that places input variables at the center of analysis, with policy implications. 相似文献
19.
从麦田和蔬菜地土样中筛选到2株具有较高抗菌活性的生防菌株YD4-6和NV11-4,测定了其抑菌活性和诱导水稻防御性相关酶活性的变化。抑菌活性测定结果表明YD4-6和NV11-4对水稻纹枯病菌、水稻稻瘟病菌、油菜菌核病菌和白菜黑斑病菌均具有较强的抑菌活性。两菌株均不产生几丁质酶活性,但NV11-4能产生纤维素酶活性。针对其对水稻病原菌的抑菌活性和纤维素酶活性的差异及其特性,研究了2个菌株诱导水稻防御性酶活性的变化。结果表明,YD4-6和NV11-4菌株均可有效诱导水稻PPO、POD、PAL、SOD活性增强,MDA含量升高。接种水稻纹枯病菌和使用YD4-6和NV11-4菌株,在使用48 h后,水稻防御酶的活性增加并达到最高,其中NV11-4菌株诱导活性比较持久;YD4-6使用后,诱导水稻的MDA含量增幅较大。结果显示,2个菌株均可有效的诱导水稻防御性酶活性增强和MDA含量增加。经16S rRNA鉴定后,菌株Y4-6确定为蜡质芽孢杆菌,NV11-4确定为枯草芽孢杆菌。 相似文献
20.
Comparing nitrate storage and remobilization in two rice cultivars that differ in their nitrogen use efficiency 总被引:2,自引:0,他引:2
Soil nitrogen (N) is available to rice crops as either nitrate or ammonium, but only nitrate can be accrued in cells and so factors that influence its storage and remobilization are important for N use efficiency (NUE). The hypothesis that the ability of rice crops to remobilize N storage pools is an indicator of NUE was tested. When two commonly grown Chinese rice cultivars, Nong Ken (NK) and Yang Dao (YD), were compared in soil and hydroponics, YD had significantly greater NUE for biomass production. The ability of each cultivar to remobilize nitrate storage pools 24 h after N supply withdrawal was compared. Although microelectrode measurements of the epidermal sub-cellular nitrate pools in leaves and roots showed similar patterns of vacuolar remobilization in both cultivars, whole-tissue analysis showed very little depletion of storage pools after 24 h. However, leaf epidermal cell cytosolic nitrate activities were significantly higher in YD when compared with NK. Before N starvation and growing in 10 mM nitrate, the xylem nitrate activity in YD was lower than that of NK. After 24 h of N starvation the xylem nitrate had decreased more in YD than in NK. Tissue analysis of stems showed that YD had accumulated significantly more nitrate than NK, and the remobilization pattern suggested that this store is important for both cultivars. Changes in nitrate reductase activity (NRA) and expression were measured. Growing in 10 mM nitrate, NRA was undetectable in roots of both cultivars, and the leaf total NRA of equivalent leaves was similar in NK and YD. When the N supply was withdrawn, after 24 h NRA in NK was reduced to 80% but no decrease was found in YD. The proportion of NRA in an active form in YD was significantly higher than that in NK under both nitrate supply and deprivation conditions. Checking NR gene expression showed that leaf expression of OsNia1 was faster to respond to nitrate deprivation than OsNia2 in both cultivars. These measurements are discussed in relation to cultivar differences and physiological markers for NUE in rice. 相似文献