177 research outputs found

    Effects of initial planting density on branch development in 4-year-old plantation grown Eucalyptus pilularis and Eucalyptus cloeziana trees

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    The effect of planting density on branch development was examined in 4-year-old Eucalyptus pilularis Sm. and Eucalyptus cloeziana F. Muell. plantations located near the coast of north-eastern NSW. Branch diameter, angle and status (live or dead) were measured along the entire stem of trees established at 1250, 1667 and 3333 stems per hectare (sph). Measurements of tree height and stem diameter at breast height over bark (DBH) were also recorded. Results showed that with an increase in initial planting density from 1250 to 1667 sph, branch size decreased, branch mortality on the lower stem increased, branch angle became more acute and DBH decreased in trees of both E. pilularis and E. cloeziana. A further increase in initial planting density from 1667 to 3333 sph did not significantly reduce branch size or branch angle but did result in increased branch mortality and decreased DBH in both species. These results suggest that increasing initial planting density from 1250 to 1667 sph will improve early branch control. However, there is no advantage in establishing trees at 3333 sph rather than 1667 sph to reduce branch size or increase branch mortality in either species. Clearwood production on the lower stem in all stocking treatments of both species was negligible at age 4

    Charge-Carrier Recombination in Halide Perovskites.

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    The success of halide perovskites in a host of optoelectronic applications is often attributed to their long photoexcited carrier lifetimes, which has led to charge-carrier recombination processes being described as unique compared to other semiconductors. Here, we integrate recent literature findings to provide a critical assessment of the factors we believe are most likely controlling recombination in the most widely studied halide perovskite systems. We focus on four mechanisms that have been proposed to affect measured charge carrier recombination lifetimes, namely: (1) recombination via trap states, (2) polaron formation, (3) the indirect nature of the bandgap (e.g., Rashba effect), and (4) photon recycling. We scrutinize the evidence for each case and the implications of each process on carrier recombination dynamics. Although they have attracted considerable speculation, we conclude that multiple trapping or hopping in shallow trap states, and the possible indirect nature of the bandgap (e.g., Rashba effect), seem to be less likely given the combined evidence, at least in high-quality samples most relevant to solar cells and light-emitting diodes. On the other hand, photon recycling appears to play a clear role in increasing apparent lifetime for samples with high photoluminescence quantum yields. We conclude that polaron dynamics are intriguing and deserving of further study. We highlight potential interdependencies of these processes and suggest future experiments to better decouple their relative contributions. A more complete understanding of the recombination processes could allow us to rationally tailor the properties of these fascinating semiconductors and will aid the discovery of other materials exhibiting similarly exceptional optoelectronic properties.EPSRC DTP Studentshi

    Energy and time resolution for a LYSO matrix prototype of the Mu2e experiment

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    We have measured the performances of a LYSO crystal matrix prototype tested with electron and photon beams in the energy range 60-450 MeV. This study has been carried out to determine the achievable energy and time resolutions for the calorimeter of the Mu2e experiment.Comment: 2 pages, 3 figures, 13th Pisa Meeting on Advanced Detector

    Pyrogenic carbon in Australian soils

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    Pyrogenic carbon (PyC), the combustion residues of fossil fuel and biomass, is a versatile soil fraction active in biogeochemical processes. In this study, the chemo-thermal oxidation method (CTO-375) was applied to investigate the content and distribution of PyC in 30 Australian agricultural, pastoral, bushland and parkland soil with various soil types. Soils were sampled incrementally to 50 cm in 6 locations and at another 7 locations at 0–10 cm. Results showed that PyC in Australian soils typically ranged from 0.27–5.62 mg/g, with three Dermosol soils ranging within 2.58–5.62 mg/g. Soil PyC contributed 2.0–11% (N = 29) to the total organic carbon (TOC), with one Ferrosol as high as 26%. PyC was concentrated either in the top (0–10 cm) or bottom (30–50 cm) soil layers, with the highest PyC:TOC ratio in the bottom (30–50 cm) soil horizon in all soils. Principal component analysis - multiple linear regression (PCA-MLR) suggested the silt-associated organic C factor accounted for 38.5% of the variation in PyC. Our findings suggest that PyC is an important fraction of the TOC (2.0–11%, N = 18) and chemically recalcitrant organic C (ROC) obtained by chemical C fractionation method accounts for a significant proportion of soil TOC (47.3–84.9%, N = 18). This is the first study comparing these two methods, and it indicates both CTO-375 and C speciation methods can determine a fraction of recalcitrant organic C. However, estimated chemically recalcitrant organic carbon pool (ROC) was approximately an order of magnitude greater than that of thermally stable organic carbon (PyC)

    Epidemiology, prehospital care and outcomes of patients arriving by ambulance with dyspnoea: An observational study

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    Background: This study aimed to determine epidemiology and outcome for patients presenting to emergency departments (ED) with shortness of breath who were transported by ambulance. Methods: This was a planned sub-study of a prospective, interrupted time series cohort study conducted at three time points in 2014 and which included consecutive adult patients presenting to the ED with dyspnoea as a main symptom. For this sub-study, additional inclusion criteria were presentation to an ED in Australia or New Zealand and transport by ambulance. The primary outcomes of interest are the epidemiology and outcome of these patients. Analysis was by descriptive statistics and comparisons of proportions. Results: One thousand seven patients met inclusion criteria. Median age was 74 years (IQR 61-68) and 46.1 % were male. There was a high rate of co-morbidity and chronic medication use. The most common ED diagnoses were lower respiratory tract infection (including pneumonia, 22.7 %), cardiac failure (20.5%) and exacerbation of chronic obstructive pulmonary disease (19.7 %). ED disposition was hospital admission (including ICU) for 76.4 %, ICU admission for 5.6 % and death in ED in 0.9 %. Overall in-hospital mortality among admitted patients was 6.5 %. Discussion: Patients transported by ambulance with shortness of breath make up a significant proportion of ambulance caseload and have high comorbidity and high hospital admission rate. In this study, >60 % were accounted for by patients with heart failure, lower respiratory tract infection or COPD, but there were a wide range of diagnoses. This has implications for service planning, models of care and paramedic training. Conclusion: This study shows that patients transported to hospital by ambulance with shortness of breath are a complex and seriously ill group with a broad range of diagnoses. Understanding the characteristics of these patients, the range of diagnoses and their outcome can help inform training and planning of services

    Establishment of the mechanism of purification and levigation of green chemistry-assisted biocomposites of red ochre (Gairika): synthesis, characterization, and antibacterial, prebiotic, antioxidant, and antacid activities of the traditional Ayurvedic medicine Laghu Sutashekhara Rasa

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    Gairika (red ochre) has a long history of influencing human civilization. Gairika is a rich source of nutrients used for reproductive and brain health. Gairika is mentioned as an antacid drug in Indian Ayurvedic medicine under Laghu Sutashekhara Rasa (LSR). However, a detailed study on LSR has not been reported to date. In the present study, LSR was prepared, and a pharmaceutical SOP (standardization procedure) was reported to obtain batch-to-batch reproducibility. LSR was characterized using FTIR, XRD, SEM-EDX, and TGA analyses. LSR was tested in vitro for its antacid activity. Advanced instrumentation revealed that LSR formation produced symmetrical particles (5–8 µm) with kaolin, kaolinite, quartz, goethite, and hematite, along with the phytoconstituents of Goghrita (clarified cow’s butter), Shunthi, and Nagawalli, as confirmed by GC-MS/MS analysis. The FTIR study revealed the formation of a chelating complex of goethite and hematite along with their phytoconstituents. XRD analysis confirmed the presence of kaolin, kaolinite, quartz, goethite, and hematite. Using in vitro antacid experiments, LSR and Shunthi demonstrated significant antacid activity as compared to antacid drugs and standards in the market, such as CaCO3. The DPPH assay revealed IC50 values of 12.16 ± 1.23 mg/mL, which is 0.0029 of Trolox-equivalent antioxidant activity. The inhibition (18 ± 4 mm) against pathogens (S. aureus, E. coli, P. aeruginosa, and B. subtilis) and the prominent growth of gut microbiota-supported strains (S. boulardii, L. paracasei, and L. plantarum) observed on LSR formulation were indicative of LSR application as a prebiotic. Here, the mechanism of purification and levigation mentioned in the classical literature of LSR was established. Overall, purification of Gairika with cow ghee and levigation with Nagawalli may enhance the solubility, bioavailability, and shelf-life of LSR through hydration and co-crystallization mechanisms. This is the first comprehensive report on the pharmaceutical validation of LSR and its characterization. The results of the present study could contribute to the development and reliable reproduction of LSR and the utility of environmental red ochre as a medicine in combination with Shunthi (Zingiber officinale Roxb.), as prescribed under Indian Ayurvedic medicine

    First observation of Bs -> D_{s2}^{*+} X mu nu decays

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    Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays Bs -> Ds+ X mu nu and Bs -> D0 K+ X mu nu are detected. Two structures are observed in the D0 K+ mass spectrum at masses consistent with the known D^+_{s1}(2536) and $D^{*+}_{s2}(2573) mesons. The measured branching fractions relative to the total Bs semileptonic rate are B(Bs -> D_{s2}^{*+} X mu nu)/B(Bs -> X mu nu)= (3.3\pm 1.0\pm 0.4)%, and B(Bs -> D_{s1}^+ X munu)/B(Bs -> X mu nu)= (5.4\pm 1.2\pm 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D_{s2}^{*+} state in Bs decays; we also measure its mass and width.Comment: 8 pages 2 figures. Published in Physics Letters

    A conceptual framework for implementation fidelity

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    <p>Abstract</p> <p>Background</p> <p>Implementation fidelity refers to the degree to which an intervention or programme is delivered as intended. Only by understanding and measuring whether an intervention has been implemented with fidelity can researchers and practitioners gain a better understanding of how and why an intervention works, and the extent to which outcomes can be improved.</p> <p>Discussion</p> <p>The authors undertook a critical review of existing conceptualisations of implementation fidelity and developed a new conceptual framework for understanding and measuring the process. The resulting theoretical framework requires testing by empirical research.</p> <p>Summary</p> <p>Implementation fidelity is an important source of variation affecting the credibility and utility of research. The conceptual framework presented here offers a means for measuring this variable and understanding its place in the process of intervention implementation.</p

    Handedness as a marker of cerebral lateralization in children with and without autism

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    We employed a multiple case studies approach to investigate lateralization of hand actions in typically and atypically developing children between 4 and 5 years of age. We report on a detailed set of over 1200 hand actions made by four typically developing boys and four boys with autism. Participants were assessed for unimanual hand actions to both objects and the self (self-directed behaviors). Individual and group analyses suggest that typically developing children have a right hand dominance for hand actions to objects and a left hand dominance for hand actions for self-directed behaviors, revealing a possible dissociation for functional specialization of the left and right hemispheres respectively. Children with autism demonstrated mixed-handedness for both target conditions, consistent with the hypothesis that there is reduced cerebral specialization in these children. The findings are consistent with the view that observed lateralized motor action can serve as an indirect behavioral marker for evidence of cerebral lateralization
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