Search results

Filter

Filetype

Your search for "*" yielded 533810 hits

Reproductive isolation of sympatric forms of the understorey palm Geonoma macrostachys in western Amazonia

The evolution of a mechanism for attaining reproductive isolation between two diverging populations is a key step in the speciation process. We studied phenotypic variation, genetic differentiation, spatial distribution and reproductive ecology in two sympatric forms of the understorey palm Geonoma macrostachys in lowland tropical rainforest in Amazonian Ecuador. The two forms were morphologically

The hybrid RANS/LES of partially premixed supersonic combustion using G/Z flamelet model

In order to describe partially premixed supersonic combustion numerically, G/Z flamelet model is developed and compared with finite rate model in hybrid RANS/LES simulation to study the strut-injection supersonic combustion flow field designed by the German Aerospace Center. A new temperature calculation method based on time-splitting method of total energy is introduced in G/Z flamelet model. Sim

Electrical Characterization of III-V Nanostructure

This thesis investigates the electronic properties of a number of novel III-V materials and material combinations for transistor applications. In particular, high-κ/InAs metal-oxide-semiconductor (MOS) structures and transport properties of GaSb nanowires have been studied. III-V semiconductors are potential candidates to replace Si-based electronics due to their outstanding electron transport pro

Simulating cross-shore material exchange at decadal scale. Model application

A model developed to describe long-term cross-shore (CS) exchange of sand and resulting profile evolution at regional scale was employed to simulate the evolution at three different sites. The model consists of modules for calculating dune erosion and overwash, bar-berm material exchange, and dune build-up by wind-blown sand transport, as described in detail in a companion paper (Larson et al., 20

Model of the evolution of mounds placed in the nearshore

A one-dimensional mathematical model is presented that describes the cross-shore evolution of a long linear mound of noncohesive sediment placed in the nearshore and exposed to non-breaking waves. The equation for the transport rate accounts for wave asymmetry and gravity, and the net rate is expressed by reference to an equilibrium profile shape. Simplifications reduce the governing equation for

Current understanding of the mechanisms by which membrane-active peptides permeate and disrupt model lipid membranes

Three classes of membrane active peptides (MAPs) are considered in this review: cell penetrating peptides (CPPs); anti-microbial peptides (AMPs), and amyloidal peptides. We summarize both experimental and theoretical results for several representative peptides in these different classes, which highlight commonalities in their interactions with model lipid membranes. While it is clear that no fixed

Collection of host-marking pheromone from Rhagoletis mendax (Diptera : Tephritidae)

Blueberry fruit fly, Rhagoletis mendax Curran (Diptera: Tephritidae), females deposit a host-marking pheromone (HMP) on the surface of fruit immediately after oviposition that deters oviposition by female conspecifics. We collected this HMP from artificial oviposition devices and faeces. In subsequent two-choice bioassays, gravid females showed a strong preference for untreated oviposition devices

Molecular crowding impacts the structure of apolipoprotein A-I with potential implications on in vivo metabolism and function

The effect molecular crowding, defined as the volume exclusion exerted by one soluble inert molecule upon another soluble molecule, has on the structure and self-interaction of lipid-free apoA-I were explored. The influence of molecular crowding on lipid-free apoA-I oligomerization and internal dynamics has been analyzed using electron paramagnetic resonance (EPR) spectroscopy measurements of nitr

Capto™ Resins for Chromatography of DNA : A Minor Difference in Ligand Composition Greatly Influences the Separation of Guanidyl-Containing Fragments

The differences in chromatographic behaviour of individual deoxynucleotides as well as small single-stranded and double-stranded DNA molecules have been examined for two resins from the Capto family: Capto Adhere and Capto Q ImpRes. Capto Adhere carries a multimodal ligand which combines strong anion with aromatic recognition, while Capto Q ImpRes is a strong anion exchanger with a chemically simi

Structural biology of starch-degrading enzymes and their regulation

Starch is a major energy source for all domains of life. Recent advances in structures of starch-degrading enzymes encompass the substrate complex of starch debranching enzyme, the function of surface binding sites in plant isoamylase, details on individual steps in the mechanism of plant disproportionating enzyme and a self-stabilised conformation of amylose accommodated in the active site of pla

InP nanowire p-type doping via Zinc indiffusion

We report an alternative pathway for p-type InP nanowire (NW) doping by diffusion of Zn species from the gas phase. The diffusion of Zn was performed in a MOVPE reactor at 350–500 °C for 5–20 min with either H2 environment or additional phosphorus in the atmosphere. In addition, Zn3P2 shells were studied as protective caps during post-diffusion annealing. This post-diffusion annealing was performe

Free induction decay in the extreme ultraviolet

We present an experimental study of controlled Free Induction Decay (FID) in the extreme ultraviolet regime excited by High-order Harmonics. The control is done by applying a delayed infrared pulse.

Power Market Structure and Renewable Energy Deployment Experiences From the MENA Region

In almost all countries in the Middle East and North Africa (MENA) region, power sectors are characterized by a high degree of vertical integration and state control. However, several countries have undertaken reforms in order to open up the power market for private sector involvement particularly in relation to renewable energy (RE) sourced electricity generation. The majority of the MENA countri

Combined cycle power plants with post-combustion CO2 capture : Energy analysis at part load conditions for different HRSG configurations

The part-load behaviour of combined cycle power plants (CCPP) equipped with post-combustion CO2 capture is analyzed. Different CCPP configurations are compared, including single-, dual- or triple-pressure level steam generators. The gas turbine is a single shaft unit using the variable guide vanes and fuel flow to control the load. The 90% CO2 capture is achieved using monoethanolamine (MEA 30%wt)

An IV Test for a Unit Root in Generally Trending and Correlated Panels

This paper proposes an IV-based panel unit root test that is general enough to accommodate general error serial and cross-section dependence, and a potentially nonlinear deterministic trend function. These allowances make the new test one of the most general around. It is also very simple to implement. Indeed, the IV statistic is asymptotically invariant to not only to all nuisance parameters char

The Influence of Social Network Characteristics on Peer Clustering in Smoking : A Two-Wave Panel Study of 19- and 23-Year-Old Swedes

The present study examines how the composition of social networks and perceived relationship content influence peer clustering in smoking, and how the association changes during the transition from late adolescence to early adulthood.The analysis was based on a Swedish two-wave survey sample comprising ego-centric network data. Respondents were 19 years old in the initial wave, and 23 when the fol

Sensor Fusion for Robotic Workspace State Estimation

We consider the problem of tool position and orientation state estimation for robot manipulators in workspace by sensor fusion of the internal robot joint measurements with inertial measurement unit data. A prerequisite for this to be successful is accurate calibration of the sensors used. Therefore, we discuss a method for calibration of the sensor with respect to the robot end-effector, which is