978 resultados para NEGATIVE REGULATION
Resumo:
Addressing inconsistencies in relational demography research, we examine the relationship between cultural dissimilarity and individual performance through the lens of social self-regulation theory, which extends the social identity perspective in relational demography with the analysis of social self-regulation. We propose that social self-regulation in culturally diverse teams manifests itself as performance monitoring (i.e., individuals' actions to meet team performance standards and peer expectations). Contingent on the status associated with individuals' cultural background, performance monitoring is proposed to have a curvilinear relationship with individual performance and to mediate between cultural dissimilarity and performance. Multilevel moderated mediation analyses of time-lagged data from 316 members of 69 teams confirmed these hypotheses. Cultural dissimilarity had a negative relationship with performance monitoring for high cultural-status members, and a positive relationship for low cultural-status members. Performance monitoring had a curvilinear relationship with individual performance that became decreasingly positive. Cultural dissimilarity thus was increasingly negatively associated with performance for high culturalstatus members, and decreasingly positively for low cultural-status members. These findings suggest that cultural dissimilarity to the team is not unconditionally negative for the individual but, in moderation, may in fact have positive motivational effects.
Resumo:
Noha az 1990-es évek első felében felbomlott az akadémiai közgazdászok sok évtizeden át örök érvényűnek hitt közmegegyezése a minimálbér szükségképpen negatív foglalkoztatási hatásáról, a túlságosan magas minimálbért minden közgazdász foglalkoztatáscsökkentő hatásúnak jósolja. Tanulmányunkban a magyar minimálbér-szabályozást e hatás szempontjából vizsgáljuk és értékeljük. / === / Although the long-held view of an unambiguously negative employment effect of a binding minimum wage was challenged by empirical findings in the early 1990’s, it is unanimously predicted that if the minimum wage is set too high it will bring about adverse employment effects. Accordingly, our study starts from an evaluation of the magnitude of the Hungarian minimum wage, i.e., of how it relates to minimum wage rates elsewhere, and of how it has developed through time. Next we inspect the main features that characterize the Hungarian system of minimum wage regulation. Theoretical views on the potential employment effect of minimum wage regulation are then surveyed and contrasted to empirical findings. The study concludes by policy recommendations. To sum up the main strand of arguments, we try to demonstrate that even though Hungary’s minimum wage, if assessed by its ratio to average and/or median full-time earnings, does not appear particularly high by international standards, it might rightly be regarded as unreasonably high in light of Hungary’s excessively low relative rate of employment among the least schooled. This diagnose should become particularly evident once one takes into account that, in sharp contrast to established rules elsewhere, a significantly higher wage floor is in effect for those with lower secondary schooling. Abolition of this legally guaranteed premium over the minimum wage as well as more moderation in minimum wage adjustments are thus highly recommended.
Resumo:
This study documents relationships between plant nutrient content and rhizome carbohydrate content of a widely distributed seagrass species, Thalassia testudinum, in Florida. Five distinct seagrass beds were sampled for leaf nitrogen, leaf phosphorus, and rhizome carbohydrate content from 1997 to 1999. All variables displayed marked intra- and inter- regional variation. Elemental ratios (mean N:P ± S.E.) were lowest for Charlotte Harbor (9.9 ± 0.2) and highest for Florida Bay (53.5 ± 0.9), indicating regional shifts in the nutrient content of plant material. Rhizome carbohydrate content (mean ± S.E.) was lowest for Anclote Keys (21.8 ± 1.6 mg g−1 FM), and highest for Homosassa Bay (40.7 ± 1.7 mg g−1 FM). Within each region, significant negative correlations between plant nutrient and rhizome carbohydrate content were detected; thus, nutrient-replete plants displayed low carbohydrate content, while nutrient-deplete plants displayed high carbohydrate content. Spearman's rank correlations between nutrient and carbohydrate content varied from a minimum in Tampa Bay (ρ = −0.2) to a maximum in Charlotte Harbor (ρ = −0.73). Linear regressions on log-transformed data revealed similar trends. This consistent trend across five distinct regions suggests that nutrient supply may play an important role in the regulation of carbon storage within seagrasses. Here we present a new hypothesis for studies which aim to explain the carbohydrate dynamics of benthic plants.
Resumo:
Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, is a pnmary contributing factor responsible for the morbidity and mortality in patients with cystic fibrosis. One of the trademarks of P. aeruginosa is its ability to resist antibiotics. P. aeruginosa does so in part through the LysR-type transcription factor, AmpR. To identify additional members of the AmpR regulon, a new algorithm called iterative enhancement of motifs was used to identify putative AmpR binding sites upstream of open reading frames in the P. aeruginosa genome. The surprising primary hit of this analysis was the promoter of an uncharacterized open reading frame, P A 415 7. P A 415 7 is located upstream ofthefep operon, which is known to be involved in iron acquisition. PA4157 shares high homology to the IclR family of transcriptional regulators which are known to regulate quorum sensing (QS), an elaborate cell-cell communication signaling system that uses quoromones. We postulated two hypotheses: 1) AmpR regulation of QS genes is mediated by PA4157, and 2) PA4157 may be involved in iron acquisition. To address the role of P A 415 7 we generated an in-frame chromosomal deletion of P A 415 7 in P. aeruginosa PA01 (PA0 PA4157). We compared PA0 PA4157 with its parent strain P A0 1 for its ability to produce quoromones using Chromobacterium violaceum as an indicator strain and LasA proteases using Staphylococcus aureus. We also tested its role in virulence using a Caenorhabditis elegans killing assay. Growth in iron-deficient media was also examined to determine if P A4157 has a potential role in iron uptake regulation. Our preliminary results suggest that P A 415 7 is not involved in quorum sensing regulation but does seem to exert a negative regulatory effect on iron uptake in P. aeruginosa P A0 1.
Resumo:
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen. Several antibiotic resistant strains of P. aeruginosa are commonly found as secondary infection in immune-compromised patients leaving significant mortality and healthcare cost. Pseudomonas aeruginosa successfully avoids the process of phagocytosis, the first line of host defense, by secreting several toxic effectors. Effectors produced from P. aeruginosa Type III secretion system are critical molecules required to disrupt mammalian cell signaling and holds particular interest to the scientists studying host-pathogen interaction. Exoenzyme S (ExoS) is a bi-functional Type III effector that ADP-ribosylates several intracellular Ras (Rat sarcoma) and Rab (Response to abscisic acid) small GTPases in targeted host cells. The Rab5 protein acts as a rate limiting protein during phagocytosis by switching from a GDP- bound inactive form to a GTP-bound active form. Activation and inactivation of Rab5 protein is regulated by several Rab5-GAPs (GTPase Activating Proteins) and Rab5-GEFs (Rab5-Guanine nucleotide Exchange Factors). Some pathogenic bacteria have shown affinity for Rab proteins during infection and make their way inside the cell. This dissertation demonstrated that Rab5 plays a critical role during early steps of P. aeruginosa invasion in J774-Eclone macrophages. It was found that live, but not heat inactivated, P. aeruginosa inhibited phagocytosis that occurred in conjunction with down-regulation of Rab5 activity. Inactivation of Rab5 was dependent on ExoS ADP-ribosyltransferase activity, and more than one arginine sites in Rab5 are possible targets for ADP-ribosylation modification. However, the expression of Rin1, but not other Rab5GEFs (Rabex-5 and Rap6) reversed this down-regulation of Rab5 in vivo. Further studies revealed that the C-terminus of Rin1 carrying Rin1:Vps9 and Rin1:RA domains are required for optimal Rab5 activation in conjunction with active Ras. These observations demonstrate a novel mechanism of Rab5 targeting to phagosome via Rin1 during the phagocytosis of P. aeruginosa. The second part of this dissertation investigated antimicrobial activities of Dehydroleucodine (DhL), a secondary metabolite from Artemisia douglasiana, against P. aeruginosa growth and virulence. Populations of several P. aeruginosa strains were completely susceptible to DhL at a concentration between 0.48~0.96 mg/ml and treatment at a threshold concentration (0.12 mg/ml) inhibited growth and many virulent activities without damaging the integrity of the cell suggesting anti-Pseudomonas activity of DhL.
Resumo:
At the crux of health disparities for women of color lies a history of maltreatment based on racial difference from their white counterparts. It is their non-whiteness that limits their access to the ideologies of “woman” and “femininity” within dominant culture. As the result of this difference, the impact of the birth control movement varied among women based on race. This project explores how the ideology attributed to the black female body limited black women’s access to “womanhood” within dominant culture, and analyzes the manners in which their reproductive autonomy was compromised as the result of changes to that ideology through time. This project operates under the hypothesis that black women’s access to certain aspects of femininity such as domesticity and motherhood reflected their roles in slave society, that black women’s reproductive value was based on the value of black children within slave culture, and that both of these factors dictated the manner in which their reproductive autonomy was managed by health professionals. Black people’s worth as a free labor force within dominant culture diminished when the Reconstruction Amendments were added to the constitution and slavery was deemed unconstitutional—resulting in the paradigmatic shift from the promotion of black fertility to its recession. America’s transition to the medicosocial regulation of black fertility through Eugenics, the role of the black elite in the movement, and the negative impact of this agenda on the reproductive autonomy of black women from low socioeconomic backgrounds are enlisted as support. The paper goes on to draw connections between post-slavery ideology of black femininity and modern-day medicosocial occurrences within clinical settings in order to advocate for increased bias training for medical professionals as a means of combating current health disparities. It concludes with the possibility that this improvement in medical training could persuade people of color to seek out medical intervention at earlier stages of illness and obtain regular check-ups by actively countering physicians’ past transgressions against them.
Resumo:
When exposed to chronic hypoxia by pathophysiological or environmental causes humans show muscle atrophy, challenging homeostasis and increasing mortality rate. Chronic hypoxia also presents with elevated myostatin peptide, a negative regulator of muscle size. This work induced acute hypoxia in healthy individuals; hypothesizing hypoxia would increase myostatin expression in both muscle and plasma in a concentration- and time-dependent manner. Hypoxia (1 % O2) reduced C2C12 myoblast migration and myotube size in vitro. Myotube atrophy was time-dependent, longer exposures showed greater atrophy. Intracellular myostatin peptide was decreased at every time point measured. Myostatin and downstream signalling pathways in muscle showed a high degree of percentage similarity between mouse and human, when amino acid sequences were directly compared. Healthy males (N = 8) were exposed to 20.9 % O2 or 11.9 % O2 for 2 hours. Following hypoxic exposure myostatin peptide was reduced in muscle but not plasma, relative to control conditions. A second cohort (N = 8) was exposed to 12.5 % O2 for 10 hours. Plasma myostatin was decreased following hypoxia, muscle myostatin trended towards increasing. A third cohort (N = 9; n = 8 lowlander, n = 1 Sherpa) was exposed to 10.7 % or 12.3 % O2 for 2 hours. Plasma myostatin was reduced at both concentrations with no difference between concentrations noted. In response to chronic hypoxia, individuals lose muscle mass. Counter to the hypothesis of an increase in myostatin in both muscle and plasma, here a consistent decrease in plasma myostatin following acute hypoxia is seen. Muscle myostatin shows a variable response, with decreasing intracellular expression seen following a 2 hour hypoxic exposure, and trends towards an increase following 10 hours of hypoxia. Decreases in plasma and muscle myostatin may represent myostatin’s movement towards peripheral compartments in these acute timeframes. Hypoxia alone is capable of altering myostatin in healthy individuals; the effects of hypoxia on myostatin appear to differ between the acute timeframes examined here and chronic exposures in environmental or disease models.
Resumo:
Compulsory education laws oblige primary and secondary schools to give each pupil positive encouragement in, for example, social, emotional, cognitive, creative, and ethical respects. This is a fairly smooth process for most pupils, but it is not as easy to achieve with others. A pattern of pupil, home or family, and school variables turns out to be responsible for a long-term process that may lead to a pupil’s dropping out of education. A systemic approach will do much to introduce more clarity into the diagnosis, potential reduction and possible prevention of some persistent educational problems that express themselves in related phenomena, for example low school motivation and achievement; forced underachievement of high ability pupils; concentration of bullying and violent behaviour in and around some types of classes and schools; and drop-out percentages that are relatively constant across time. Such problems have a negative effect on pupils, teachers, parents, schools, and society alike. In this address, I would therefore like to clarify some of the systemic causes and processes that we have identified between specific educational and pupil characteristics. Both theory and practice can assist in developing, implementing, and checking better learning methods and coaching procedures, particularly for pupils at risk. This development approach will take time and require co-ordination, but it will result in much better processes and outcomes than we are used to. First, I will diagnose some systemic aspects of education that do not seem to optimise the learning processes and school careers of some types of pupils in particular. Second, I will specify cognitive, social, motivational, and self-regulative aspects of learning tasks and relate corresponding learning processes to relevant instructional and wider educational contexts. I will elaborate these theoretical notions into an educational design with systemic instructional guidelines and multilevel procedures that may improve learning processes for different types of pupils. Internet-based Information and Communication Technology, or ICT, also plays a major role here. Third, I will report on concrete developments made in prototype research and trials. The development process concerns ICT-based differentiation of learning materials and procedures, and ICT-based strategies to improve pupil development and learning. Fourth, I will focus on the experience gained in primary and secondary educational practice with respect to implementation. We can learn much from such practical experience, in particular about the conditions for developing and implementing the necessary changes in and around schools. Finally, I will propose future research. As I hope to make clear, theory-based development and implementation research can join forces with systemic innovation and differentiated assessment in educational practice, to pave the way for optimal “learning for self-regulation” for pupils, teachers, parents, schools, and society at large.
Resumo:
Thesis (Ph.D.)--University of Washington, 2016-08
Resumo:
Thesis (Ph.D.)--University of Washington, 2016-08
Resumo:
Ten years ago, cohabitants in Scotland had no statutory rights in respect of their deceased partner’s estate. Section 29 of the Family Law (Scotland) Act 2006 gave cohabitants the right to apply to the court for discretionary provision from their deceased partner’s intestate estate. This thesis examines the process of making such an application and the way that the provisions have been applied in practice. The juxtaposition of the Family Law (Scotland) Act 2006 and the existing rules for intestate succession in the Succession (Scotland) Act 1964 is considered, with particular focus on the subordination of cohabitants’ rights to the succession rights of a surviving spouse, and the negative impact that this may have on children. It is concluded that the current succession framework is incapable of protecting cohabitants and children in reconstituted families. Potential measures are considered to displace the traditional primacy of marital succession rights, and provide a fair and flexible system of succession law that is capable of dealing with complex family structures.
Resumo:
This paper examines the policy effects of multilevel regulation in Europe. It finds that the extent to which negative integration effectively narrows the range of policy options available domestically tends to be overstated. Drawing on empirical evidence from EU-induced reform in electricity supply and postal delivery, the paper illustrates that liberalisation and institutional reorganisation may lead to relatively little policy change. Although a lack of centralised regulatory capacity at the European level is identified as a key explanatory factor for the cases studied, the findings also point to the relevance of sector specificities and the role of exogenous drivers of change.
Resumo:
Two main types of noncoding small RNA molecules have been found in plants: microRNAs (miRNAs) and small interfering RNAs (siRNAs). They differ in their biogenesis and mode of action, but share similar sizes (20-24 nt). Their precursors are processed by Dicer-Like RNase III (dcl) proteins present in Arabidopsis thaliana, and in their mature form can act as negative regulators of gene expression, being involved in a vast array of plant processes, including plant development, genomic integrity or response to stress. Small-RNA mediated regulation can occurs at transcriptional level (TGS) or at post-transcriptional level (PTGS). In recent years, the role of gene silencing in the regulation of expression of genes related to plant defence responses against bacterial pathogens is becoming clearer. Comparisons carried out in our lab between the expression profiles of different mutants affected in gene silencing, and plants challenged with Pseudomonas syringae pathovar tomato DC3000, led us to identify a set of uncharacterized R genes, belonging to the TIR-NBS-LRR gene family, differentially expressed in these conditions. Through the use of bioinformatics tools, we found a miRNA* of 22 nt putatively responsible for down-regulating expression of these R genes through the generation of siRNAs. We have also found that the corresponding pri-miRNA is down-regulated after PAMP-perception in a SA-dependent manner. We also demonstrate that plants with altered levels of miRNA* (knockdown lines or overexpression lines) exhibit altered PTI-associated phenotypes, suggesting a role for this miRNA* in this defence response against bacteria. In addition we identify one of the target genes as a negative regulator of defence response against Pseudomonas syringae.
Resumo:
Negative symptoms in schizophrenia are characterized by deficits in normative experiences and expression of emotion. Social anhedonia (diminished pleasure from social experiences) is one negative symptom that may impact patients’ motivation to engage in meaningful social relationships. Past research has begun to examine the mechanisms that underlie social anhedonia, but it is unclear how this lack of social interest may impact the typically positive effects of social buffering and social baseline theory whereby social support attenuates stress. The present pilot study examines how social affiliation through hand holding is related to subjective and neural threat processing, negative symptoms, and social functioning. Twenty-one participants (14 controls; 7 schizophrenia) developed social affiliation with a member of the research staff who served as the supportive partner during the threat task. Participants displayed greater subjective benefit to holding the hand of their partner during times of stress relative to being alone or with an anonymous experimenter, as indicated by self-reported increased positive valence and decreased arousal ratings. When examining the effects of group, hand holding, and their interaction on the neurological experience of threat during the fMRI task, the results were not significant. However, exploratory analyses identified preliminary data suggesting that controls experienced small relative increases in BOLD signal to threat when alone compared to being with the anonymous experimenter or their partner, whereas the schizophrenia group results indicated subtle relative decreases in BOLD signal to threat when alone compared to either of the hand holding conditions. Additionally, within the schizophrenia group, more positive valence in the partner condition was associated with less severe negative symptoms, better social functioning, and more social affiliation, whereas less arousal was correlated with more social affiliation. Our pilot study offers initial insights about the difficulties of building and using social affiliation and support through hand holding with individuals with schizophrenia during times of stress. Further research is necessary to clarify which types of support may be more or less beneficial to individuals with schizophrenia who may experience social anhedonia or paranoia with others that may challenge the otherwise positive effects of social buffering and maintaining a social baseline.
Resumo:
The central role of translation regulation in the control of critical cellular processes has long been recognized. Yet the systematic exploration of quantitative changes in translation at a genome-wide scale in response to specific stimuli has only recently become technically feasible. Using a genetic approach, we have identified new Arabidopsis weak-ethylene insensitive mutants that also display defects in translation, which suggested the existence of a previously unknown molecular module involved in ethylene-mediated translation regulation of components of this signaling pathway. To explore this link in detail, we implemented for Arabidopsis the ribosome-footprinting technology, which enables the study of translation at a whole-genome level at single codon resolution[1]. Using ribosome-footprinting we examined the effects of short exposure to ethylene on the Arabidopsis translatome looking for ethylene-triggered changes in translation rates that could not be explained by changes in transcript levels. The results of this research, in combination with the characterization of a subset of the aforementioned weak-ethylene insensitive mutants that are defective in the UPF genes (core-components of the nonsense-mediated mRNA decay machinery), uncovered a translation-based branch of the ethylene signaling pathway[2]. In the presence of ethylene, translation of a negative regulator of ethylene signaling EBF2 is repressed, despite induced transcription of this gene. These translational effects of ethylene require the long 3´UTR of EBF2 (3´EBF2), which is recognized by the C-terminal end of the key ethylene-signaling protein EIN2 (EIN2C) in the cytoplasm once EIN2C is released from the ER-membrane by proteolytic cleavage. EIN2C binds the 3´EBF2, recruits the UPF proteins and moves to P-bodies, where the translation of EBF2 in inhibited despite its mRNA accumulation. Once the ethylene signal is withdrawn, the translation of the stored EBF2 mRNAs is resumed, thus rapidly dampening the ethylene response. These findings represent a mechanistic paradigm of gene-specific regulation of translation in response to a key growth regulator. Translation regulatory elements can be located in both 3′ and 5′ UTRs. We are now focusing on the ead1 and ead2 mutants, another set of ethylene-signaling mutants defective in translational regulation. Ribosome-footprinting on the ead1 mutant revealed an accumulation of translating ribosomes in the 5´UTRs of uORF-containing genes and reduction in the levels of ribosomes in the main ORF. The mutant is also impaired in the translation of GFP when this reporter is fused to WT 5´UTR of potential EAD1 targets but not when GFP is fused to the uORF-less versions of the same 5´UTRs. Our hypothesis is that EAD1/2 work as a complex that is required for the efficient translation of mRNAs that have common structural (complex 5´UTR with uORFs) and functional (regulation of key cellular processes) features. We are working towards the identification of the conditions where the EAD1 regulation of translation is required. [1] Ingolia, N. et al. (2009) Genome-Wide Analysis in Vivo of Translation with Nucleotide Resolution Using Ribosome Profiling. Science, 324; 218-222 [2] Merchante, C. et al. (2015) Gene-Specific Translation Regulation Mediated by the Hormone-Signaling Molecule EIN2. Cell, 163(3): 684-697