41 research outputs found
Bidirectional Associations Between Sibling Relationships and Parental Support During Adolescence
Sibling relationships and parental support are important for adolescents’ development and well-being, yet both are likely to change during adolescence. Since adolescents participate in both the sibling relationship and the parent–child relationship, we can expect sibling relationships and parental support to be associated with each other. Theoretically, it can be expected that there is either a spillover from one relationship to another (congruence hypothesis) or that one relationship can compensate for the other (compensation hypothesis). However, research examining these associations in adolescence is limited. The present study longitudinally investigated the bidirectional associations between sibling relationships and parental support during adolescence. For five consecutive years, data were collected using self-reports of 428 families, consisting of a father, a mother, and two adolescent siblings. The mean ages of the first-born (52.8% males) and second-born (47.7% males) were 15 and 13 years at T1, respectively. For the second-born siblings, prospective associations were found between sibling relationships and adolescent-reported parental support in early adolescence, with no differences between same-sex and mixed-sex dyads. These associations were not found for first-born siblings or for parents’ reports of support. The findings suggest a spillover from the sibling relationship to adolescent-reported parental support only in early adolescence. Findings and implications are discussed in terms of the congruence/spillover and the compensation hypothesis
Being Mum’s Confidant, a Boon or Bane? Examining Gender Differences in the Association of Maternal Disclosure with Adolescents’ Depressive Feelings
This article reports on a longitudinal study investigating gender differences in the association between maternal disclosure and adolescents’ depressive symptoms. Little research has examined the relationship of parental disclosure to adolescents’ depressive symptoms and research on sex differences is particularly lacking. In a sample of 428 families with a mean age of 13.36 (52% female) of the target adolescents, maternal and children’s disclosure and depressive symptoms were assessed twice with an interval of 4 years. Controlling for the quality of the parent–child relationship and levels of maternal depressive symptoms, the analyses revealed an interaction effect for child’s gender, moderating the effect of maternal disclosure on adolescents’ depressive symptoms. Higher levels of maternal disclosure were accompanied by lower levels of depressive symptoms in girls and higher levels of depressive symptoms in boys. Gender differences in socialization, communication, individuation and social networks might explain why daughters and sons are differently affected by maternal disclosure
65 nm feature sizes using visible wavelength 3-D multiphoton lithography
© 2007 Optical Society of AmericaThe definitive version of this paper is available at: http://dx.doi.org/10.1364/OE.15.003426DOI: 10.1364/OE.15.003426Nanoscale features as small as 65 ± 5 nm have been formed reproducibly by using 520 nm femtosecond pulsed excitation of a 4,4'- bis(di-n-butylamino)biphenyl chromophore to initiate crosslinking in a triacrylate blend. Dosimetry studies of the photoinduced polymerization were performed on chromophores with sizable two-photon absorption crosssections at 520 and 730 nm. These studies show that sub-diffraction limited line widths are obtained in both cases with the lines written at 520 nm being smaller. Three-dimensional multiphoton lithography at 520 nm has been used to fabricate polymeric woodpile photonic crystal structures that show stop bands in the near-infrared spectral region
Parental alcohol use, alcohol-related problems, and alcohol-specific attitudes, alcohol-specific communication, and adolescent excessive alcohol use and alcohol-related problems: An indirect path model.
Alcohol-specific parent–child communication has often been studied in relation to regular alcohol use of adolescents. However, it might be as important to focus on adolescent problematic alcohol use. In addition, the way parents communicate with their children about alcohol might depend on their own (problematic) drinking behaviors. Therefore, the current study examined the direct effects of parental alcohol use, alcohol related problems, and parental alcohol-specific attitudes on adolescent excessive drinking and alcohol related problems later in life. It also looked at indirect effects via alcohol-specific communication. The sample consisted of 428 Dutch families including fathers, mothers and adolescents from two age groups (13 and 15 years old) at T1, who have been surveyed annually for 5 years. We tested the model with structural equation modeling (SEM). The results showed that parental alcohol-related problems were positively associated with communication about alcohol, which in turn was related with less excessive adolescent drinking and alcohol-related problems. Lenient parental attitudes about alcohol and parental alcohol-related problems were directly related to more excessive drinking and alcohol-related problems in adolescents. In conclusion, alcohol-specific communication intervenes in the relationship between parental alcohol-related problems and adolescent excessive drinking and alcohol-related problems. This indicates that in family alcohol interventions targeted at youth alcohol use, parental alcohol-related problems should be taken into account. (PsycInfo Database Record (c) 2023 APA, all rights reserved
Cultivation of heterotrophic algae on paper waste material and digestate
This study investigates the cellulases-catalyzed hydrolysis of newspaper waste and paper slurries as carbon source in combination with digestate from anaerobic digestion as nitrogen source for the heterotrophic cultivation of Chlorella sorokiniana. The enzymatic hydrolysis of paper slurries resulted in a hydrolysate containing 27.2 g l 121 glucose reflecting a 78% cellulose conversion. A maximum Chlorella sorokiniana biomass yield of 3.64 g l 121 was achieved within 91 h of cultivation under consumption of 9.7 g l 121 glucose. The most efficient cultivation converted 1 g l 121 glucose into 0.42 g l 121 biomass. A strong decrease in pH of the batch cultures due to ammonium consumption and CO2 production by algae cells inhibited full glucose consumption for high concentrations of 17 g l 121 glucose. Characterizing the amino acid content and pattern of the biomass revealed an amino acid fraction of 32.9% with Alanine as the most frequent amino acid
Biorefining: the role of endoglucanases in refining of cellulose fibers
With an annual production of more than 400 million tons, paper is the main product of the largest biorefinery process industrially implemented. Enzymes have been used for pulp refining to dramatically reduce energy consumption. However, exact mechanisms related to the individual enzymes are hardly understood. Yet, this knowledge would be important to predict enzyme performance in industrial processes. Three commercial refining enzyme formulations showed different endoglucanase (1.25 nkat mg 121\u201313.7 nkat mg 121), \u3b2-glucosidase (0.57 nkat mg 121\u20131.34 nkat mg 121) and xylanase activities (1.78 nkat ml 121\u201362.1 nkat mg 121) on model substrates. Additionally, distinct amounts of reducing sugars from hardwood sulfate pulp were released. Endoglucases were purified from each formulation by using hydrophobic interaction and anion exchange chromatography and showed molecular weights from 20 to 55 kDa and specific activities ranging between 3.11 and 26.3 nkat mg 121 according to endoglucanase specific derivatized cellopentaose (CellG5). Refining trials of hardwood sulfate pulp were conducted using a PFI laboratory mill and fiber properties such as degree of refining or fiber length and properties of formed sheets like tensile index were monitored. Thereby, enzymes were dosed based on identical endoglucanase activity on CellG5. Enzyme formulations and purified endoglucanases led to an increase of the degree of refining of up to 47.9 [\ub0SR] at 6000 PFI revolutions while the tensile index was improved by up to 76.0 Nm g 121. In summary, refining effects can be primarily attributed to endoglucanases indicating activity on CellG5 being a suitable parameter for enzyme dosing
Prospective relationships between sleep problems and substance use, internalizing and externalizing problems.
While research has shown that sleep problems and substance use are reciprocally associated in adults, much less is known about this association in early adolescence. The main aim of the current longitudinal study was to explore bidirectional relationships between sleep problems, substance use, internalizing and externalizing problems in young adolescents. A prospective design was used incorporating two waves (approximately 1 year interval). A total of 555 young adolescents (290 females, M age = 13.96) participated in this study. All participants completed self-report measures in classrooms during regular school hours (questionnaires about sleep quality and sleep hygiene were used to measure sleep problems). The results indicated that sleep problems predicted changes in substance use, internalizing and externalizing problems over time, but problem behaviours did not predict changes in sleep problems, adjusted for gender, age and puberty. One exception was that alcohol use negatively predicted changes in sleep problems. This study suggests that sleep problems are important precursors of substance use, internalizing and externalizing problems in adolescence
Effects of enzymes on the refining of different pulps
Comparative studies of the effects of two commercial enzyme formulations on fiber refining were conducted. Extensive basic characterisation of the enzymes involved, assessment of their hydrolytic activities on different model substrates as well as on different pulps (softwood sulfate, softwood sulfite, hardwood sulfate) were evaluated. Both enzyme formulations showed endoglucanase as well as some xylanase and \u3b2-glucosidase activity. In addition, Enzyme A reached a CMC end viscosity of 19.5\u2009mPa compared to 11.1\u2009mPa for Enzyme B. Reducing sugar release almost doubled from 695\u2009\u3bcmol\u2009mL 121 for hardwood sulfate pulp to 1300\u2009\u3bcmol\u2009mL 121 for softwood sulfite pulp with Enzyme B under the same conditions. Enzyme A increased the degree of refining even under non-ideal conditions from 23\u2009\ub0SR to up to 50\u2009\ub0SR. Further characterization of hand sheets, made from enzyme pre-treated and refined cellulose fibers with Enzyme A and B, showed that Enzyme A had the best effects leading to hand sheets with increased tensile strength and low air permeability. In summary, the increase in the degree of refining seen for Enzyme A correlated to higher xylanase and \u3b2-glucosidase activity and lower endoglucanase activity
Results of the 'In control: No alcohol!' pilot study.
More than 50% of Dutch 12-year olds already started drinking. Since it is known that delaying the onset of alcohol use results in a lower risk of alcohol-related problems, the recently developed ‘In control: No alcohol!’ prevention program is targeted at elementary school children and their mothers. In this pilot study, the success of program implementation and impact of the program on quality of alcohol-specific communication, rules and monitoring were evaluated, using a randomized controlled design. A total of 108 children (11–12 years) and their mothers participated in the prevention program, while the control group consisted of 105 dyads. Families participating in the experimental condition showed an increase in frequency of alcohol-specific communication and 75% of the dyads reported that they took part in at least 3 of 5 magazines, suggesting implementation was successful. The program led to an increase in quality of communication but only for those dyads in which mothers’ alcohol use was above average. The program led parents to set up a non-drinking contract with their children and to monitor their children more closely. Results are promising but need to be replicated in a larger longitudinal study. (PsycInfo Database Record (c) 2020 APA, all rights reserved