7,322 research outputs found

    Growth, yield and quality responses to gibberellic acid (GA3) of Wax apple Syzygium samarangense var. Jambu air madu fruits grown under field conditions

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    A study was carried out to investigate the effects of gibberellic acid (GA3) on the growth and development of the red jambu air madu fruits (Syzygium samarangense). Various horticultural parameters were monitored during two seasons of fruit growth between December, 2008 to December, 2009 with the application of three concentrations of GA3 at 20, 50 and 100 mg/L. It was observed that the application of GA3 at 50 mg/L increased fruit length and diameter. Furthermore, it enhanced faster fruit growth and color development in addition to increasing fruit number, weight and yield. It also decreased premature fruit dropping. However, spraying with 20 mg/L GA3 increased the number of buds and fruit setting and reduced bud dropping before anthesis. With regard to fruit quality, the application of GA3 at 50 mg/L increased total soluble solids (TSS), total sugar, total biomass and total flavonoids content in the fruits by 112, 97, 45 and 92% compared with the control treatment. In addition, anthocyanin content, total phenol and antioxidant activity was higher in GA3 treated fruits. From this study, it can be concluded that spraying with 50 mg/L GA3 once a week results in better yield and quality of jambu madu fruits under field conditions.Key words: Gibberellin, growth, quality, wax apple, yield

    The Nucleosome Acidic Patch Regulates the H2B K123 Monoubiquitylation Cascade and Transcription Elongation in Saccharomyces cerevisiae

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    Eukaryotes regulate gene expression and other nuclear processes through the posttranslational modification of histones. In S. cerevisiae, the mono-ubiquitylation of histone H2B on lysine 123 (H2B K123ub) affects nucleosome stability, broadly influences gene expression and other DNA-templated processes, and is a prerequisite for additional conserved histone modifications that are associated with active transcription, namely the methylation of lysine residues in H3. While the enzymes that promote these chromatin marks are known, regions of the nucleosome required for the recruitment of these enzymes are undefined. To identify histone residues required for H2B K123ub, we exploited a functional interaction between the ubiquitin-protein ligase, Rkr1/Ltn1, and H2B K123ub in S. cerevisiae. Specifically, we performed a synthetic lethal screen with cells lacking RKR1 and a comprehensive library of H2A and H2B residue substitutions, and identified H2A residues that are required for H2B K123ub. Many of these residues map to the nucleosome acidic patch. The substitutions in the acidic patch confer varying histone modification defects downstream of H2B K123ub, indicating that this region contributes differentially to multiple histone modifications. Interestingly, substitutions in the acidic patch result in decreased recruitment of H2B K123ub machinery to active genes and defects in transcription elongation and termination. Together, our findings reveal a role for the nucleosome acidic patch in recruitment of histone modification machinery and maintenance of transcriptional integrity

    Order of magnitude increase in photocatalytic rate for hierarchically porous anatase thin films synthesized from zinc titanate coatings

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    In this paper we report on the use of aerosol assisted chemical vapour deposition (AACVD) to form thin films of the zinc titanate phases using zinc acetate and titanium isopropoxide as precursors in methanol solution. Analysis by XRD and XPS found that through variation in experimental conditions we have been able to synthesize films of zinc titanate with composition of Zn2TiO4 or Zn0.3Ti2.7O4.94, which adopt the spinel and pseudobrookite structure respectively. In addition, we have also formed hybrid films of Zn2TiO4 with either ZnTiO3 or ZnO. Using a technique previously reported with powders, the mixed ZnO and Zn2TiO4 films were treated with acid to produce porous Zn2TiO4 which, through reduction and vapour leaching of zinc, were converted to hierarchically porous thin films of anatase TiO2. This conversion was monitored by XRD. Analysis of photocatalytic activity of the hierarchically porous titania, using dye and stearic acid degradation tests, found a factor of 12 to 14 increase in rates of photocatalysis over conventional TiO2 thin films. Finally we are able to report a maximum formal quantum efficiency for stearic acid degradation of 1.76 × 10−3 molecules per photon

    Brain activation during face perception: evidence of a developmental change.

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    Behavioral studies suggest that children under age 10 process faces using a piecemeal strategy based on individual distinctive facial features, whereas older children use a configural strategy based on the spatial relations among the face's features. The purpose of this study was to determine whether activation of the fusiform gyrus, which is involved in face processing in adults, is greater during face processing in older children (12-14 years) than in younger children (8-10 years). Functional MRI scans were obtained while children viewed faces and houses. A developmental change was observed: Older children, but not younger children, showed significantly more activation in bilateral fusiform gyri for faces than for houses. Activation in the fusiform gyrus correlated significantly with age and with a behavioral measure of configural face processing. Regions believed to be involved in processing basic facial features were activated in both younger and older children. Some evidence was also observed for greater activation for houses versus faces for the older children than for the younger children, suggesting that processing of these two stimulus types becomes more differentiated as children age. The current results provide biological insight into changes in visual processing of faces that occur with normal development

    Differential investment in visual and olfactory brain regions is linked to the sensory needs of a wasp social parasite and its host

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    Obligate insect social parasites evolve traits to effectively locate and then exploit their hosts, whereas hosts have complex social behavioral repertoires, which include sensory recognition to reject potential conspecific intruders and heterospecific parasites. While social parasites and host behaviors have been studied extensively, less is known about how their sensory systems function to meet their specific selective pressures. Here, we compare investment in visual and olfactory brain regions in the paper wasp Polistes dominula, and its obligate social parasite P. sulcifer, to explore the links among sensory systems,brain and behavior. Our results show significant relative volumetric differences between these two closely related species, consistent with their very different life histories. Social parasites show proportionally larger optic lobes and central complex to likely navigate long-distance migrations and unfamiliar landscapes to locate the specific species of hosts they usurp. Contrastingly, hosts have larger antennal lobes and calyces of the mushroom bodies compared with social parasites, as predicted by their sensory means to maintain social cohesion via olfactory signals, allocate colony tasks, forage, and recognize conspecific and heterospecific intruders. Our work suggests how this tradeoff between visual and olfactory brain regions may facilitate different sensory adaptations needed to perform social and foraging tasks by the host, including recognition of parasites, or to fly long distances and successful host localizing by the social parasite

    Talking a team into being in online workplace collaborations: the discourse of virtual work

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    Digital communication technologies led to a revolution in how people interact at work: relying on computer-mediated communication technologies is now a must, rather than an alternative. This empirical study investigates how colleagues in a virtual team use synchronous online communication platform in the workplace. Inspired by the conceptualisation of web-based communication platforms as tool, place or context of social construction, we explore the discursive strategies that contribute to the construction of the team’s shared sense of purpose and identity, a collegial atmosphere and consequently lead to effective collaboration. The close analyses of real-life data from a multinational workplace provide insights into the everyday communication practices of virtual team members. Our findings supplement organisational literature based on etic observations of the effectiveness of virtual work and provide a basis for further theorisations about how communication technologies affect the ecology of and discourse practices in computer-mediated communication at work

    Associations between reliable changes in depression and changes in BMI, total body fatness and visceral adiposity during a 12-month weight loss trial.

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    We investigated associations between changes in depression and body composition over a 12-month weight loss trial. Of the 298 adults (BMI > 27 m/kg2), 219 with complete depression and body composition data were included. A 10-item Center for Epidemiologic Studies Depression Scale measured depression; dual-energy X-ray absorptiometry measured body composition. Multinomial logistic regression predicted reliable changes in depression by BMI, body fat (BF) and visceral adiposity (VAT). Multiplicative interaction terms tested modification by sex and ethnicity. Participants with increases in body composition were less likely to experience improvements in depression (BMI: RRR = 0.79 (0.68-0.91), p < 0.01; BF: RRR = 0.97 (0.94 - 0.99), p = 0.01; VAT: RRR = 0.99 (0.98-1.00), p = 0.02), but not worsening of depression (BMI: RRR = 1.29 (0.96-1.73), p = 0.10; BF: RRR = 1.04 (0.99-1.09), p = 0.15; VAT: RRR = 1.01 (1.00-1.03), p = 0.18). Sex and ethnicity interaction terms were not significant. However, the relationship was only significant among females, among non-Latinos for BMI and BF, and among Latinos for VAT. Our study supports the association between depression and obesity and highlights the need for longitudinal studies investigating VAT and depression in diverse ethnic groups
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