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Reciprocal Effects (reciprocal + effects)
Selected AbstractsParent , Adolescent Relationships and Girls' Unhealthy Eating: Testing Reciprocal EffectsJOURNAL OF RESEARCH ON ADOLESCENCE, Issue 4 2002Andrea Bastiani Archibald This longitudinal study tested the direction of associations between parent ,adolescent relationships and adolescent girls' unhealthy eating. Girls (N= 184) were seen at Time 1 (M age = 14.30 years), and then again 2 years later (Time 2; M age = 16.04 years). At both assessment periods, they completed measures that assessed their eating attitudes and behaviors, relationships with their parents, height, weight, and age of menarche. Whereas unhealthy family relationships have been hypothesized as a precursor to unhealthy eating attitudes and behaviors, it is also possible that increases in these behaviors contribute to more negative relationships within the family. Structural equation modeling was employed to simultaneously investigate the longitudinal influence of parent , adolescent relationships on girls' unhealthy eating, and girls' unhealthy eating on parent , adolescent relationships. The model was tested with the following controls: body mass (kg/m2), pubertal timing and age. A longitudinal direct effect was found for unhealthy eating on parent, adolescent relationships; however, no direct effect was found for parent, adolescent relationships on unhealthy eating over time. For middle, and late,adolescent girls, it appears that unhealthy eating behaviors and attitudes are predictive of less positive parent , adolescent relationships over time. [source] Longitudinal Study of Preadolescent Sport Self-Concept and Performance: Reciprocal Effects and Causal OrderingCHILD DEVELOPMENT, Issue 6 2007Herbert W. Marsh Do preadolescent sport self-concepts influence subsequent sport performance? Longitudinal data (Grades 3, 4, and 6) for young boys and girls (N= 1,135; mean age = 9.67) were used to test reciprocal effects model (REM) predictions that sport self-concept is both a cause and a consequence of sport accomplishments. Controlling prior sport performance (performance-based measures and teacher assessments), prior sport self-concept had positive effects on subsequent sport performance in both Grade 4 and Grade 6 and for both boys and girls. Coupled with previous REM studies of adolescents in the academic domain, this first test for preadolescents in the sport domain supports the generalizability of REM predictions over gender, self-concept domain, preadolescent ages, and the transition from primary to secondary school. [source] Reciprocal effects in true potato seed breeding in short-day length environmentsPLANT BREEDING, Issue 4 2003A. M. Golmirzaie Abstract Reciprocal crosses may have significantly distinct performances regarding tuber characteristics in potato, suggesting the importance of cytoplasmic effects in this crop. The selection of parents for true potato seed breeding therefore needs to consider this potential effect when determining the direction of a cross. The aim of this research was to determine whether a broad-based true potato seed breeding population, developed at the Centro Internacional de la Papa, could be affected by cytoplasmic effects in the short-day length environments of the tropics. Two random sets of reciprocal biparental crosses were included in the first set of experiments, which were grown in two contrasting Peruvian locations. Only one out of 14 reciprocal crosses showed significantly distinct performance for tuber yield and tuber set. In the second set, only one of each of the 12 reciprocal crosses had distinct performance for vine earliness, days to flowering and flowering intensity, but four of the reciprocal crosses in the second set showed distinct pollen production. The results suggest that cytoplasmic effects in this breeding population are more important for reproductive characteristics such as pollen production than for tuber yield. This finding is not surprising because male sterility in potato results from the interaction between sensitive cytoplasm and dominant nuclear genes. [source] The alpha-amino group of l -arginine mediates its antioxidant effectEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2 2001S. Wallner Antioxidant effects may constitute part of the possible antiatherogenic effects of the amino acid l -arginine. These antioxidant properties were further characterized in a model of lipoprotein oxidation. Oxidation of lipoproteins in unfractionated human serum was continuously monitored by a fluorescent probe. The antioxidant effects of l -arginine, N -,-acetyl-arginine and vitamin E in combination with l -arginine were measured after initiation of free radical generation with either copper or 2,2,-azobis(2-amidinopropane) hydrochloride (AAPH). The half-time of the fast propagation rate for copper-induced lipoprotein oxidation increased after incubation with l -arginine in a dose-dependent manner (P < 0·01). N -,-acetyl-arginine did not show such effects. Vitamin E and l -arginine show different effects on copper-induced oxidation, the former increasing only lag-time, the latter increasing only propagation rate, and do not have reciprocal effects. In contrast to copper-induced oxidation, l -arginine increased the lag-time of AAPH-induced lipoprotein oxidation (P < 0·01), with no effect on the propagation rate at physiological concentrations. Again, N -,-acetyl-arginine did not show any antioxidant effects. Our experiments provide further evidence that mechanisms other than serving as a substrate for the NO-synthase could be involved in the antiatherosclerotic effect of l -arginine. In addition, our experiments clearly show, that the antioxidant effect of l -arginine is due to a chemical moiety different from that serving as the substrate for NO biosynthesis. [source] Early growth response 2 regulates the survival of thymocytes during positive selectionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2010Victoria J. Lawson Abstract The early growth response (Egr) transcription factor family regulates multiple steps during T-cell development. We examine here the role played by Egr2 in positive selection. In double-positive cells, Egr2 is upregulated immediately following TCR ligation, and its expression requires both the MAPK and calcineurin signaling pathways. Inducible transgenic and knockout mice were generated to cause gain- or loss-of-function of Egr2 in double-positive cells, and had reciprocal effects; more mature single-positive cells were made when Egr2 was overexpressed, and fewer when Egr2 was absent. These defects were associated with changes in the survival of positively selected cells rather than perturbation of positive selection or immediate post-selection signaling. The survival function of Egr2 at least partly depends upon its ability to activate the cytokine-mediated survival pathway, likely through negative regulation of both the IL-7R and suppressor of cytokine signaling 1 (Socs1), the molecular switch whose downregulation normally results in restored responsiveness to cytokine signaling following selection. While gain of Egr2 caused a decrease in Socs1 mRNA, loss of Egr2 resulted in downregulation of IL-7R, upregulation of Socs1, and inhibition of Stat5 phosphorylation and IL-7-mediated survival post-selection. Therefore, expression of Egr2 following positive selection links the initial TCR signaling event to subsequent survival of signaled cells. [source] Knowledge in Interior DesignJOURNAL OF INTERIOR DESIGN, Issue 1 2005Anna Marshall-Baker Ph.D. Anna Marshall-Baker teaches in the Department of Interior Architecture at the University of North Carolina at Greensboro where she focuses on sustaining design and the reciprocal effects of environments and human development, particularly in the neonatal intensive care unit (NICU). With academic and practical experience in fine and commercial art, interior design, and psychology, she serves as a member of the Recommended Standards Consensus Committee for NICU Design, Interim Chair of the Sustaining Design Task Force for IDEC, Department Undergraduate Program Coordinator, Past-President of IDEC, and a reviewer for the Journal of Interior Design. [source] Longitudinal Effects of Hope on Depression and Anxiety: A Latent Variable AnalysisJOURNAL OF PERSONALITY, Issue 1 2007Randolph C. Arnau ABSTRACT This study tested the prospective effects of hope on depression and anxiety using a longitudinal design. A sample of 522 college students completed self-report measures of hope, depression, and anxiety at three time points, with 1-month delays between administrations. Structural equation modeling was employed to test two cross-lagged panel models of the reciprocal effects of the Agency and Pathways components of hope on depression and anxiety. Results indicated statistically significant negative effects for the Agency component of hope on later depression but no unique effect of the Pathways component of hope on depression. Likewise, Agency showed a statistically significant negative effect on later anxiety, but again Pathways had no significant influence on anxiety. In both cases, neither depression nor anxiety demonstrated any longitudinal effects on either the Agency or Pathways components of hope. Implications of these findings are discussed, along with potential directions for future research. [source] Enemy-mediated apparent competition: empirical patterns and the evidenceOIKOS, Issue 2 2000Enrique J. Chaneton Apparent competition arises when two victim species negatively affect each other (,,,,) by enhancing the equilibrium density or changing the foraging behaviour of a shared natural enemy. Shared enemies can also mediate non-reciprocal (,,,0) indirect effects, i.e. indirect amensalism, whenever one prey species is not affected by the presence of alternative prey. We review 34 studies on terrestrial and freshwater systems to evaluate the extent to which apparent competition has been perceived as a reciprocal (,,,,) or non-reciprocal (,,,0) interaction. We found only three studies showing reciprocal effects between apparent competitors. Indirect amensalism was documented in 10 studies and could be inferred for 16 other cases (76% in total). The remaining five studies provided insufficient data to determine the form of indirect interaction. The apparent prevalence of non-reciprocal enemy-mediated interactions resembles that observed for resource-based interspecific competition. Amensal indirect effects via shared predation may result from differences in population size, nutritional value, susceptibility to attack, or asynchronous dynamics of alternative prey, or the predator's feeding preferences. Moreover, experimental protocols may confound the actual form of apparent competition through short-term observations, incomplete designs, or biased consideration of conspicuous interactions, leading to reciprocal effects being overlooked. We conclude that, at present, it is still difficult to determine the relative role of apparent competition vs indirect amensalism in natural food webs because most published studies have failed to document in full interactions via shared enemies. [source] Effects of positive and negative affect on electromyographic activity over zygomaticus major and corrugator superciliiPSYCHOPHYSIOLOGY, Issue 5 2003Jeff T. Larsen Abstract Pleasant stimuli typically elicit greater electromyographic (EMG) activity over zygomaticus major and less activity over corrugator supercilii than do unpleasant stimuli. To provide a systematic comparison of these 2 measures, the authors examined the relative form and strength of affective influences on activity over zygomaticus major and corrugator supercilii. Self-reported positive and negative affective reactions and facial EMG were collected as women (n=68) were exposed to series of affective pictures, sounds, and words. Consistent with speculations based on known properties of the neurophysiology of the facial musculature, results revealed a stronger linear effect of valence on activity over corrugator supercilii versus zygomaticus major. In addition, positive and negative affect ratings indicated that positive and negative affect have reciprocal effects on activity over corrugator supercilii, but not zygomaticus major. [source] Interspecific competition and rarity in mudsnails: feeding interactions between and within Hydrobia acuta neglecta and sympatric Hydrobia speciesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2005R.S.K. Barnes Abstract 1.Using production of faecal pellets as a proxy for feeding rate, possible reciprocal effects of the widespread and abundant mudsnails Hydrobia ulvae and Hydrobia ventrosa on the rare Hydrobia acuta neglecta were investigated under the sea-water salinity conditions in which all three species occur naturally in East Anglia, UK. 2.Over a density range equivalent to 1000,34 000 m,2, H. acuta and H. ventrosa (though not H. ulvae) at some point displayed an intraspecific reduction in egestion with increase in density. For H. acuta, every 5000 extra snails above a threshold of 16 000 m,2 reduced egestion by up to 8%; and for H. ventrosa, every 5000 extra snails above a threshold of 8000 m,2 reduced egestion by an average 7%. 3.Keeping the density of one test species constant at 4000 m,2 whilst varying that of a sympatric one from 0 up to 30 000 m,2 indicates that H. ulvae has a marked effect on H. acuta at all densities, decreasing its egestion by 10% for every 5000 m,2H. ulvae also present, but that H. acuta has no such reciprocal effect on H. ulvae. H. ventrosa had no effect on egestion in H. acuta, although H. acuta did have some minor effect on H. ventrosa, on average decreasing its egestion by 3% for every 5000 m,2H. acuta present. 4.The intensity of intraspecific competition within H. acuta, therefore, exceeds that exerted on H. acuta by H. ventrosa, and likewise intraspecific effects within H. ventrosa generally outweigh any interspecific effect from H. acuta. The effect of H. ulvae on H. acuta, however, exceeds that intraspecifically within H. acuta. 5.These results are discussed in relation to the rarity of H. acuta neglecta. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||