907 resultados para 765-68


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In the asymmetric unit of the title co-crystal, C12H14N4O2S . C7H5NO4 there are two independent but conformationally similar heterodimers, which are formed through intermolecular N-H...O(carboxy) and carboxyl O-H...N hydrogen-bond pairs, giving a cyclic motif [graph set R2/2(8)]. The dihedral angles between the rings in the sulfonamide molecules are 78.77(8) and 82.33(9)deg. while the dihedral angles between the ring and the CO2H group in the acids are 2.19(9) and 7.02(10)deg. A two-dimensional structure parallel to the ab plane is generated from the heterodimer units through hydrogen-bonding associations between NH2 and sulfone groups. Between neighbouring two-dimensional arrays there are two types of aromatic pi-pi stacking interactions involving either one of the pyrimidine rings and a 4-nitrobenzoic acid molecule [minimum ring centroid separation = 3.5886(9)A] or two acid molecules [minimum ring centroid separation = 3.7236(10)A].

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Purpose: The purpose of this research is to understand reflective journalling in a first year Public Health practice unit. Design/methodology/approach: This research uses pure phenomenography to interpret students descriptions of reflective journalling. Data was collected from thirty-two students enrolled in PUB215 Public Health Practice in the School of Public Health, Queensland University of Technology. Participants completed a brief open-ended questionnaire to evaluate the first assessment item in this unit, a Reflective Journal. Questionnaire responses were analysed through Dahlgren and Fallsberg’s (1991) seven phases of data analysis. Findings: The Reflective Journal required students to reflect on lecture content from five of seven guest speakers. Participants responses were categorised into four conceptions - 1) engagement in learning, 2) depth of knowledge, 3) understanding the process and 4) doing the task. Participants describe reflective journalling as a conduit to think critically about the content of the guest speakers presentations. Other participants think journalling is a vehicle to think deeply about their potential career pathways. Some define journalling as a pragmatic operation where practical issues are difficult to navigate. The Reflective Journal successfully a) engaged students learning, b) increased students depth of knowledge and c) deepened students understanding of the journalling process. Originality/value: This research gives an insight into how first year public health students understand reflective journalling, supports educators in reflective journalling assessments and confirms a Reflective Journal assessment can move student reflection towards higher order thinking about practice.

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Navigational collisions are one of the major safety concerns in many seaports. Despite the extent of recent works done on port navigational safety research, little is known about harbor pilot’s perception of collision risks in port fairways. This paper uses a hierarchical ordered probit model to investigate associations between perceived risks and the geometric and traffic characteristics of fairways and the pilot attributes. Perceived risk data, collected through a risk perception survey conducted among the Singapore port pilots, are used to calibrate the model. Intra-class correlation coefficient justifies use of the hierarchical model in comparison with an ordinary model. Results show higher perceived risks in fairways attached to anchorages, and in those featuring sharper bends and higher traffic operating speeds. Lesser risks are perceived in fairways attached to shoreline and confined waters, and in those with one-way traffic, traffic separation scheme, cardinal marks and isolated danger marks. Risk is also found to be perceived higher in night.

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In the structure of the title salt 2C7H10N+.C8H2Cl2O4(2-) .H2O the two benzylaminium anions have different conformations, one being essentially planar the other having the side-chain rotated out of the benzene plane (minimum ring to side-chain C-C-C-N torsion angles = -3.6(6) and 50.1(5)\%, respectively). In the 4,5-dichlorophthalate dianion the carboxyl groups make ihedral angles of 23.0(2) and 76.5(2)\% with the benzene ring. Aminium N-H...O and water O-H...O hydrogen-bonding associations with carboxyl O-atom acceptors give a two-dimensional duplex sheet structure which extends along the (011) plane. Weak pi-pi interactions are also present between the benzene ring and one of the cation rings [minimum ring centroid separation = 3.749(3)Ang.

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This paper focuses on malicious workplace gossip from the perspective of those targeted by this dark form of organisational communication. Findings from a large exemplarian action research project are reported that suggest malicious gossip can be an influential form of power that strongly contributes to counterproductive organisational behaviour. The discussion draws upon the emergent themes from the research to highlight the negative consequences of malicious gossip for those targeted and their organisations, and in so doing, elaborates on the phenomenon of workplace mobbing. This research highlights the importance of recognising gossip as an effective, though dark, form of power and the value of rational discourse for improving organisational communication.

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Sorghum (Sorghum bicolor (L.) Moench) is the world’s fifth major cereal crop and holds importance as a construction material, food and fodder source. More recently, the potential of this plant as a biofuel source has been noted. Despite its agronomic importance, the use of sorghum production is being constrained by both biotic and abiotic factors. These challenges could be addressed by the use of genetic engineering strategies to complement conventional breeding techniques. However, sorghum is one of the most recalcitrant crops for genetic modification with the lack of an efficient tissue culture system being amongst the chief reasons. Therefore, the aim of this study was to develop an efficient tissue culture system for establishing regenerable embryogenic cell lines, micropropagation and acclimatisation for Sorghum bicolor and use this to optimise parameters for genetic transformation via Agrobacterium-mediated transformation and microprojectile bombardment. Using five different sorghum cultivars, SA281, 296B, SC49, Wray and Rio, numerous parameters were investigated in an attempt to establish an efficient and reproducible tissue culture and transformation system. Using immature embryos (IEs) as explants, regenerable embryogenic cell lines (ECLs) could only be established from cultivars SA281 and 296B. Large amounts of phenolics were produced from IEs of cultivars, SC49, Wary and Rio, and these compounds severely hindered callus formation and development. Cultivar SA281 also produced phenolics during regeneration. Attempts to suppress the production of these compounds in cultivars SA281 and SC49 using activated charcoal, PVP, ascorbic acid, citric acid and liquid filter paper bridge methods were either ineffective or had a detrimental effect on embryogenic callus formation, development and regeneration. Immature embryos sourced during summer were found to be far more responsive in vitro than those sourced during winter. In an attempt to overcome this problem, IEs were sourced from sorghum grown under summer conditions in either a temperature controlled glasshouse or a growth chamber. However, the performance of these explants was still inferior to that of natural summer-sourced explants. Leaf whorls, mature embryos, shoot tips and leaf primordia were found to be unsuitable as explants for establishing ECLs in sorghum cultivars SA281 and 296B. Using the florets of immature inflorescences (IFs) as explants, however, ECLs were established and regenerated for these cultivars, as well as for cultivar Tx430, using callus induction media, SCIM, and regeneration media, VWRM. The best in vitro responses, from the largest possible sized IFs, were obtained using plants at the FL-2 stage (where the last fully opened leaf was two leaves away from the flag leaf). Immature inflorescences could be stored at 25oC for up to three days without affecting their in vitro responses. Compared to IEs, the IFs were more robust in tissue culture and showed responses which were season and growth condition independent. A micropropagation protocol for sorghum was developed in this study. The optimum plant growth regulator (PGR) combination for the micropropagation of in vitro regenerated plantlets was found to be 1.0 mg/L BAP in combination with 0.5 mg/L NAA. With this protocol, cultivars 296B and SA281 produced an average of 57 and 13 off-shoots per plantlet, respectively. The plantlets were successfully acclimatised and developed into phenotypically normal plants that set seeds. A simplified acclimatisation protocol for in vitro regenerated plantlets was also developed. This protocol involved deflasking in vitro plantlets with at least 2 fully-opened healthy leaves and at least 3 roots longer than 1.5 cm, washing the media from the roots with running tap water, planting in 100 mm pots and placing in plastic trays covered with a clear plastic bag in a plant growth chamber. After seven days, the corners of the plastic cover were opened and the bags were completely removed after 10 days. All plantlets were successfully acclimatised regardless of whether 1:1 perlite:potting mix, potting mix, UC mix or vermiculite were used as potting substrates. Parameters were optimised for Agrobacterium-mediated transformation (AMT) of cultivars SA281, 296B and Tx430. The optimal conditions were the use of Agrobacterium strain LBA4404 at an inoculum density of 0.5 OD600nm, heat shock at 43oC for 3 min, use of the surfactant Pluronic F-68 (0.02% w/v) in the inoculation media with a pH of 5.2 and a 3 day co-cultivation period in dark at 22oC. Using these parameters, high frequencies of transient GFP expression was observed in IEs precultured on callus initiation media for 1-7 days as well as in four weeks old IE- and IF-derived callus. Cultivar SA281 appeared very sensitive to Agrobacterium since all tissue turned necrotic within two weeks post-exposure. For cultivar 296B, GFP expression was observed up to 20 days post co-cultivation but no stably transformed plants were regenerated. Using cultivar Tx430, GFP was expressed for up to 50 days post co-cultivation. Although no stably transformed plants of this cultivar were regenerated, this was most likely due to the use of unsuitable regeneration media. Parameters were optimised for transformation by particle bombardment (PB) of cultivars SA281, 296B and Tx430. The optimal conditions were use of 3-7 days old IEs and 4 weeks old IF callus, 4 hour pre- and post-bombardment osmoticum treatment, use of 0.6 µm gold microparticles, helium pressure of 1500 kPa and target distance of 15 cm. Using these parameters for PB, transient GFP expression was observed for up to 14, 30 and 50 days for cultivars SA281, 296B and Tx430, respectively. Further, the use of PB resulted in less tissue necrosis compared to AMT for the respective cultivars. Despite the presence of transient GFP expression, no stably transformed plants were regenerated. The establishment of regenerable ECLs and the optimization of AMT and PB parameters in this study provides a platform for future efforts to develop an efficient transformation protocol for sorghum. The development of GM sorghum will be an important step towards improving its agronomic properties as well as its exploitation for biofuel production.