1,169 research outputs found

    FruitGrowth - Gasburning in orchards - Environment friendly weed control

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    Gas burning makes treatment of weed organic. The new ENVO-DAN burner saves 40% gas and treats 1/2 meter in width.It can be mounted on a standard lawn tractor, orchard tractor or a mobile robot. The modular burner system for burning weeds in orchards can be configurated to your needs

    Mixing of ultracold atomic clouds by merging of two magnetic traps

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    We demonstrate a method to make mixtures of ultracold atoms that does not make use of a two-species magneto-optical trap. We prepare two clouds of 87Rb atoms in distinct magnetic quadrupole traps and mix the two clouds by merging the traps. For correctly chosen parameters the mixing can be done essentially without loss of atoms and with only minor heating. The basic features of the process can be accounted for by a classical simulation of particle trajectories. Such calculations indicate that mixing of different mass species is also feasible, opening the way for using the method as a starting point for making quantum gas mixtures.Comment: 12 pages, 13 figures. Fig. 10 corrected. Fig. 13 updated with more points and better statistics. A couple of paragraphs rephrased and typos corrected. References update

    Probabilistic state preparation of a single molecular ion by projection measurement

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    We show how to prepare a single molecular ion in a specific internal quantum state in a situation where the molecule is trapped and sympathetically cooled by an atomic ion and where its internal degrees of freedom are initially in thermal equilibrium with the surroundings. The scheme is based on conditional creation of correlation between the internal state of the molecule and the translational state of the collective motion of the two ions, followed by a projection measurement of this collective mode by atomic ion shelving techniques. State preparation in a large number of internal states is possible.Comment: 4 pages, 2 figures, 2 table

    Regional Characterisation of Hard-Bottom Nursery Habitat for Juvenile Caribbean Spiny Lobster (Panulirus argus) Using Rapid Assessment Techniques

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    Shallow, hard-bottom habitat constitutes approximately 30% of the coastal waters of south Florida, United States, yet it is a chronically understudied feature of the marine seascape in this region. In this study, we characterised the general biogeographic and structural features of shallow benthic hard-bottom communities in the Florida Keys, and related those to the abundance of juvenile Caribbean spiny lobster (Panulirus argus), the target of one of Florida\u27s most economically valuable fisheries. We used rapid assessment techniques to survey more than 100 hard-bottom sites in the Florida Keys to estimate the percentage bottom coverage of vegetation (seagrass and macroalgae) and the abundance of sponges, octocorals, hard corals, and other crevice-bearing structures, as well as the abundance of juvenile lobsters. Using a multivariate statistical approach, we evaluated the relationship between habitat and size-specific juvenile lobster abundance and quantitatively verified the existence of six generally accepted biogeographic subregions. Although the types of hard-bottom shelters used by juvenile lobsters varied somewhat among these subregions, in all regions, branching-candle sponges and octocorals were under-used by lobsters, whereas loggerhead sponges, coral heads, and solution holes were over-used (i.e., used more frequently than expected based on their availability). There was also an ontogenetic transition in the shelter preference of juvenile lobsters; small juveniles tended to occupy a variety of sponges, whereas large juveniles preferred hard structures such as coral heads and solution holes. This study yields the first quantitative biogeographic description of hard-bottom communities of the Florida Keys, and confirms the suspected relationship between the structural features of hard-bottom habitat and the value of these communities as nurseries for juvenile spiny lobster

    Distinct nature of static and dynamic magnetic stripes in cuprate superconductors

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    We present detailed neutron scattering studies of the static and dynamic stripes in an optimally doped high-temperature superconductor, La2_2CuO4+y_{4+y}. We find that the dynamic stripes do not disperse towards the static stripes in the limit of vanishing energy transfer. We conclude that the dynamic stripes observed in neutron scattering experiments are not the Goldstone modes associated with the broken symmetry of the simultaneously observed static stripes, but rather that the signals originate from different domains in the sample. These domains may be related by structural twinning, or may be entirely different phases, where the static stripes in one phase are pinned versions of the dynamic stripes in the other. Our results explain earlier observations of unusual dispersions in underdoped La2−x_{2-x}Srx_xCuO4_{4} (x=0.07x=0.07) and La2−x_{2-x}Bax_xCuO4_{4} (x=0.095x=0.095). Our findings are relevant for all compounds exhibiting magnetic stripes, and may thus be a vital part in unveiling the nature of high temperature superconductivity

    Models and metaphors: complexity theory and through-life management in the built environment

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    Complexity thinking may have both modelling and metaphorical applications in the through-life management of the built environment. These two distinct approaches are examined and compared. In the first instance, some of the sources of complexity in the design, construction and maintenance of the built environment are identified. The metaphorical use of complexity in management thinking and its application in the built environment are briefly examined. This is followed by an exploration of modelling techniques relevant to built environment concerns. Non-linear and complex mathematical techniques such as fuzzy logic, cellular automata and attractors, may be applicable to their analysis. Existing software tools are identified and examples of successful built environment applications of complexity modelling are given. Some issues that arise include the definition of phenomena in a mathematically usable way, the functionality of available software and the possibility of going beyond representational modelling. Further questions arising from the application of complexity thinking are discussed, including the possibilities for confusion that arise from the use of metaphor. The metaphor of a 'commentary machine' is suggested as a possible way forward and it is suggested that an appropriate linguistic analysis can in certain situations reduce perceived complexity

    Further evidence of Chelonid herpesvirus 5 (ChHV5) latency : High levels of ChHV5 DNA detected in clinically healthy marine turtles

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    The Chelonid herpesvirus 5 (ChHV5) has been consistently associated with fibropapillomatosis (FP), a transmissible neoplastic disease of marine turtles. Whether ChHV5 plays a causal role remains debated, partly because while FP tumours have been clearly documented to contain high concentrations of ChHV5 DNA, recent PCRbased studies have demonstrated that large proportions of asymptomatic marine turtles are also carriers of ChHV5. We used a real-time PCR assay to quantify the levels of ChHV5 Glycoprotein B (gB) DNA in both tumour and non-tumour skin tissues, from clinically affected and healthy turtles drawn from distant ocean basins across four species. In agreement with previous studies, higher ratios of viral to host DNA were consistently observed in tumour versus non-tumour tissues in turtles with FP. Unexpectedly however, the levels of ChHV5 gB DNA in clinically healthy turtles were significantly higher than in non-tumour tissues from FP positive turtles. Thus, a large proportion of clinically healthy sea turtle populations worldwide across species carry ChHV5 gB DNA presumably through persistent latent infections. ChHV5 appears to be ubiquitous regardless of the animals' clinical conditions. Hence, these results support the theory that ChHV5 is a near ubiquitous virus with latency characteristics requiring co-factors, possibly environmental or immune related, to induce FP

    The inter- and intrarater reliability and agreement for field-based assessment of scapular control, shoulder range of motion, and shoulder isometric strength in elite adolescent athletes

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    Objectives To investigate the intra- and interrater reliability and agreement for field-based assessment of scapular control, shoulder range of motion (ROM), and shoulder isometric strength in elite youth athletes. Design Test-retest reliability and agreement study. Setting Eight blinded raters (two for each assessment) assessed players on field during two testing sessions separated by one week. Participants 162 elite youth handball players with or without a history of previous shoulder pain within the preceding six months. Main outcome measures Kappa (κ) and prevalence-adjusted bias-adjusted kappa (PABAK) coefficients for scapular control reliability, and 95% limits of agreement (LOA) for ROM and strength agreement. Results Scapular control demonstrated substantial to almost perfect reliability (κ 0.67 to 0.84, PABAK from 0.68 to 0.88). Mean strength values ranged from 0.9 N/kg to 1.6 N/kg, and LOAs ranged from −0.7 N/kg to 0.8 N/kg. Rotational strength revealed additionally systematic bias between and within rater. No or acceptable systematic bias were evident for ROM and abduction strength measures. Mean values and LOAs for ROM ranged between 39.9° to 52.3°, and from −12.6° to 9.9°, respectively. Conclusions Scapular control and ROM can be assessed on the field with acceptable reliability. The threshold for reliable measurements of isometric strength using handheld-dynamometers is high
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