34 research outputs found

    Spatial phylogenetics of the native woody plant species in Hainan, China

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    To better identify biodiversity hotspots for conservation on Hainan Island, a tropical island in southern China, we assessed spatial variation in phylogenetic diversity and species richness using 18,976 georeferenced specimen records and a newly reconstructed molecular phylogeny of 957 native woody plants. Within this framework, we delineated bioregions based on vegetation composition and mapped areas of neoendemism and paleoendemism to identify areas of priority for conservation. Our results reveal that the southwest of Hainan is the most important hot spot for endemism and plant diversity followed by the southeast area. The distribution of endemic species showed a scattered, rather than clustered, pattern on the island. Based on phylogenetic range-weighted turnover metrics, we delineated three major vegetational zones in Hainan. These largely correspond to natural secondary growth and managed forests (e.g., rubber and timber forests) in central Hainan, old-growth forests and natural secondary growth forest at the margins of Hainan, and nature reserves on the island (e.g., Jianfeng and Diaoluo National Nature Reserves). Our study helps to elucidate potential botanical conservation priorities for Hainan within an evolutionary, phylogenetic framework

    Optimum electrode configurations for fast ion separation in microfabricated surface ion traps

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    For many quantum information implementations with trapped ions, effective shuttling operations are important. Here we discuss the efficient separation and recombination of ions in surface ion trap geometries. The maximum speed of separation and recombination of trapped ions for adiabatic shuttling operations depends on the secular frequencies the trapped ion experiences in the process. Higher secular frequencies during the transportation processes can be achieved by optimising trap geometries. We show how two different arrangements of segmented static potential electrodes in surface ion traps can be optimised for fast ion separation or recombination processes. We also solve the equations of motion for the ion dynamics during the separation process and illustrate important considerations that need to be taken into account to make the process adiabatic

    Microfabricated Ion Traps

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    Ion traps offer the opportunity to study fundamental quantum systems with high level of accuracy highly decoupled from the environment. Individual atomic ions can be controlled and manipulated with electric fields, cooled to the ground state of motion with laser cooling and coherently manipulated using optical and microwave radiation. Microfabricated ion traps hold the advantage of allowing for smaller trap dimensions and better scalability towards large ion trap arrays also making them a vital ingredient for next generation quantum technologies. Here we provide an introduction into the principles and operation of microfabricated ion traps. We show an overview of material and electrical considerations which are vital for the design of such trap structures. We provide guidance in how to choose the appropriate fabrication design, consider different methods for the fabrication of microfabricated ion traps and discuss previously realized structures. We also discuss the phenomenon of anomalous heating of ions within ion traps, which becomes an important factor in the miniaturization of ion traps

    Engineering of microfabricated ion traps and integration of advanced on-chip features

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    Atomic ions trapped in electromagnetic potentials have long been used for fundamental studies in quantum physics. Over the past two decades, trapped ions have been successfully used to implement technologies such as quantum computing, quantum simulation, atomic clocks, mass spectrometers and quantum sensors. Advanced fabrication techniques, taken from other established or emerging disciplines, are used to create new, reliable ion-trap devices aimed at large-scale integration and compatibility with commercial fabrication. This Technical Review covers the fundamentals of ion trapping before discussing the design of ion traps for the aforementioned applications. We overview the current microfabrication techniques and the various considerations behind the choice of materials and processes. Finally, we discuss current efforts to include advanced, on-chip features in next-generation ion traps

    Influence of genetic and environmental factors on lactation http://www.openveterinaryjournal.com F.R. Al-Samarai et al

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    ABSTRACT Data on 100 Holstein-Friesian cows for a period of 15 years (1988-2002) were analyzed using least squares and maximum likelihood methods. Lactation components such as lactation length, peak yield, milk yield and age at calving averaged 319±56, 474±42 liters, 3661±785 liters, 1963±636 days respectively. The h 2 estimates were 0.49, 0.29, 0.32 and 0.535 for these parameters, respectively. Seasonal analysis revealed that there was no influence of calving season on lactation components. Summer, Autumn, Winter and Spring had lactation length 323±50, 317±49, 313±56 and 321±55 days, monthly peak yield 477±77, 472±70, 466±53 and 482±73 kg, and milk yield 3685±766, 3593±817, 3645±677, 3724±864 kg., respectively

    Synthesis of titania-bentonite nanocomposite and its applications in water-based drilling fluids

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    Titania or TiO2-bentonite nanocomposite was synthesised by environmental friendly and cost effective hydrothermal method. Synthesised nanocomposite was successfully characterised by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). The target of the study was to enhance the rheological behaviour of the water-based drilling fluid (WBDF) by using synthesised nanocomposite. The experimental results revealed that Titania-bentonite nanocomposite exhibited better rheological characteristics than conventional WBDF. Rheological properties in particular yield point (YP) and 10-min gel strength (10-min GS) were improved by 57 % and 40 % compared to basic drilling fluid after addition of 1.0 g of the synthesised nanocomposite at 65.56 °C. API filtrate loss volume and High Pressure High Temperature (HPHT) filtrate loss volume were slightly reduced by 10 %, and 9.2 %. These scientific results can be used to formulate enhanced WBDF at elevated temperatures

    Assessment of Fate of Thiodicarb Pesticide in Sandy Clay Loam Soil

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    In present study the fate of thiodicarb pesticide in sandy clay loam soil was investigated through its adsorption and leaching using HPLC. Experimental results revealed that thiodicarb follows first order kinetic with rate constant value of 0.711 h-1 and equilibrium study showed that Freundlich model was best fitted with multilayer adsorption capacity 3.749 mol/g and adsorption intensity 1.009. Therefore, adsorption of thiodicarb was multilayer, reversible and non-ideal. Leaching study has indicated intermediate mobility of thiodicarb with water due to its solubility, while field study showed the non-leacher nature. However both adsorption and leaching were heavily affected by soil characteristics. As the soil taken was sandy clay loam hence due to clay texture adsorption was higher because of vacant sites existing and greater surface area. For this the pesticide has remained adsorbed in above 20 cm soil layer as clearly seen from field study, minor amount was recorded in third layer of soil having 21-30 cm depth. The leached amount of thiodicarb in first and last part of water was 1.075 and 0.003 ng/”l. The general trend observed for adsorption in column and field soil was decreased downwards from 2.027 to 0.618 and 5.079 to 0.009 ng/”l

    Banana peel: an effective biosorbent for aflatoxins

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    This work reports the application of banana peel as a novel bioadsorbent for in vitro removal of five mycotoxins (aflatoxins (AFB1, AFB2, AFG1, AFG2) and ochratoxin A). The effect of operational parameters including initial pH, adsorbent dose, contact time and temperature were studied in batch adsorption experiments. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and point of zero charge (pHpzc) analysis were used to characterise the adsorbent material. Aflatoxins’ adsorption equilibrium was achieved in 15 min, with highest adsorption at alkaline pH (6–8), while ochratoxin has not shown any significant adsorption due to surface charge repulsion. The experimental equilibrium data were tested by Langmuir, Freundlich and Hill isotherms. The Langmuir isotherm was found to be the best fitted model for aflatoxins, and the maximum monolayer coverage (Q0) was determined to be 8.4, 9.5, 0.4 and 1.1 ng mg−1 for AFB1, AFB2, AFG1 and AFG2 respectively. Thermodynamic parameters including changes in free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were determined for the four aflatoxins. Free energy change and enthalpy change demonstrated that the adsorption process was exothermic and spontaneous. Adsorption and desorption study at different pH further demonstrated that the sorption of toxins was strong enough to sustain pH changes that would be experienced in the gastrointestinal tract. This study suggests that biosorption of aflatoxins by dried banana peel may be an effective low-cost decontamination method for incorporation in animal feed diets. © 2016 Informa UK Limited, trading as Taylor & Francis Group

    Max phase based saturable absorber for mode-locked erbium-doped fiber laser

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    We presented an ultrashort pulse generation in an erbium-doped fiber laser cavity using MAX-PVA as a mode-locker. A thin film of SA was prepared by mixing PVA with Ti3AlC2 as a saturable absorber inside the laser cavity. The optical nonlinearity was also demonstrated, revealing a saturable absorption of 2%, a non-saturable absorption of 58.2%, and a saturation intensity of 1.63 MW/cm2. The excellencies of MAX-PVA was proven as it initiates ultrafast laser with a duration of 3.68 ps corresponds to a repetition rate of 1.887 MHz. The ease of preparation, together with its superior optical, physical, thermal, and mechanical properties, makes it a favorable SA for pulse generation in an all-fiberized laser cavity
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