1,902 research outputs found
Characterisation of species and diversity of Anopheles gambiae Keele Colony
Anopheles gambiae sensu stricto was recently reclassified as two species, An. coluzzii and An. gambiae s.s., in wild-caught mosquitoes, on the basis of the molecular form, denoted M or S, of a marker on the X chromosome. The An. gambiae Keele line is an outbred laboratory colony strain that was developed around 12 years ago by crosses between mosquitoes from 4 existing An. gambiae colonies. Laboratory colonies of mosquitoes often have limited genetic diversity because of small starting populations (founder effect) and subsequent fluctuations in colony size. Here we describe the characterisation of the chromosomal form(s) present in the Keele line, and investigate the diversity present in the colony using microsatellite markers on chromosome 3. We also characterise the large 2La inversion on chromosome 2. The results indicate that only the M-form of the chromosome X marker is present in the Keele colony, which was unexpected given that 3 of the 4 parent colonies were probably S-form. Levels of diversity were relatively high, as indicated by a mean number of microsatellite alleles of 6.25 across 4 microsatellites, in at least 25 mosquitoes. Both karyotypes of the inversion on chromosome 2 (2La/2L+a) were found to be present at approximately equal proportions. The Keele colony has a mixed M- and S-form origin, and in common with the PEST strain, we propose continuing to denote it as an An. gambiae s.s. line
Verification of ZVS boost converter with resonant circuit & modelling of an accurate two-diode PV array system simulator using MATLAB simulink
This thesis proposes a MATLAB Simulink simulator for Photo Voltaic (PV) Array system. The main contribution is the utilisation of a Two-Diode model to represent a PV cell. This model is preferred because of its better accuracy at low irradiance levels. A PV of Kyocera (KC200GT) 50*10 Array is taken & the characteristics curves are plotted. The same simulator can be interfaced with MPPT algorithms & Power Electronics converters for better efficiency. The P-V & I-V Curves of this simulator is found in exact with that given by the manufacturers. It is expected that the proposed work can be very useful for PV professionals who require a simple, fast & accurate PV simulator in order to design their systems. A detailed analysis of a resonant circuit based soft-switching boost-converter for PV applications is also performed. The converter operates at Zero Voltage Switching (ZVS) turn-on and turn-off of the main switch, & Zero Current Switching (ZCS) turn-on and ZVS turn-off of the auxiliary switch due to resonant circuit incorporated into the circuit. Detailed operation of the converters, analysis of various modes, simulation as well as experimental results for the design has also been aptly presented. The systems are modelled & simulated in MATLAB 2013a 64-bit version and the output waveforms are shown
A New Colorimetric Assay for Methionyl Aminopeptidases: Examination of the Binding of a New Class of Pseudopeptide Analog Inhibitors
A direct and convenient spectrophotometric assay has been developed for methionine aminopeptidases (MetAPs). The method employs the hydrolysis of a substrate that is a methionyl analogue of p-nitroaniline (l-Met-p-NA), which releases the chromogenic product p-nitroaniline. This chromogenic product can be monitored continuously using a UV–Vis spectrophotometer set at 405 nm. The assay was tested with the type I MetAP from Escherichia coli (EcMetAP-I) and the type II MetAP from Pyrococcus furiosus (PfMetAP-II). Using l-Met-p-NA, the kinetic constants kcat and Km were determined for EcMetAP-I and PfMetAP-II and were compared with those obtained with a “standard” high-performance liquid chromatography (HPLC) discontinuous assay. The assay has also been used to determine the temperature dependence of the kinetic constant kcat for PfMetAP-II as well as to screen two novel pseudopeptide inhibitors of MetAPs. The results demonstrate that l-Met-p-NA provides a fast, convenient, and effective substrate for both type I and type II MetAPs and that this substrate can be used to quickly screen inhibitors of MetAPs
Forecasting seasonal time series with computational intelligence: on recent methods and the potential of their combinations
Accurate time series forecasting is a key issue to support individual and or- ganizational decision making. In this paper, we introduce novel methods for multi-step seasonal time series forecasting. All the presented methods stem from computational intelligence techniques: evolutionary artificial neu- ral networks, support vector machines and genuine linguistic fuzzy rules. Performance of the suggested methods is experimentally justified on sea- sonal time series from distinct domains on three forecasting horizons. The most important contribution is the introduction of a new hybrid combination using linguistic fuzzy rules and the other computational intelligence methods. This hybrid combination presents competitive forecasts, when compared with the popular ARIMA method. Moreover, such hybrid model is more easy to interpret by decision-makers when modeling trended series.The research was supported by the European Regional Development Fund in the IT4Innovations Centre of Excellence project (CZ.1.05/1.1.00/02.0070). Furthermore, we gratefully acknowledge partial support of the project KON- TAKT II - LH12229 of MSˇMT CˇR
The influence of structural changes on electrical and magnetic characteristics of amorphous powder of the nixmoy alloy
Nickel and molybdenum alloy powder was electrodeposited on a titanium cathode from a NiSO4⋅7H2O and (NH4)6 Mo7O24⋅4H2O ammonium solution. The desired chemical composition, structure, size and shape of particles in the powder samples were achieved by an appropriate choice of electrolysis parameters (current density, composition and temperature of the solution, cathode material and electrolysis duration). Metal coatings form in the current density range 15 mA cm-2<j<30 mA cm-2. If the current density is greater than 40mA cm-2 then powders form. The chemical composition of powder samples depends on the current density of electrodeposition. The molybdenum content in the powder increases with the increase of current density (in the low current density range), while in the higher current density range the molybdenum content in the alloy decreases with the increase of the current density of deposition. Smaller sized particles form at higher current density. X-ray analysis, differential scanning calorimetric and measurements of the temperature dependence of electric resistance and magnetic permeability of the powder samples were all used to establish a predominantly amorphous structure of the powder samples formed at the current density of j≥70mA cm-2. The crystalline particle content in the powder samples increases with the decrease of the current density of deposition. Powder heating causes structural changes. The process of thermal stabilization of nickel and molybdenum amorphous powders takes place in the temperature interval from 463K to 573K and causes a decrease in electrical resistance and increase in magnetic permeability. The crystallization temperature depends on the value of current density of powder electrodeposition. Powder formed at j=180 mA cm-2 begins to crystallize at 573K, while the powder deposited at j=50 mA cm-2 begins to crystallize at 673K. Crystallization of the powder causes a decrease in electric resistivity and magnetic permeability. The Curie temperature of the crystallized powders is about 10 K higher than the Curie temperature of amorphous powders
The Phase Diagram of 1-in-3 Satisfiability Problem
We study the typical case properties of the 1-in-3 satisfiability problem,
the boolean satisfaction problem where a clause is satisfied by exactly one
literal, in an enlarged random ensemble parametrized by average connectivity
and probability of negation of a variable in a clause. Random 1-in-3
Satisfiability and Exact 3-Cover are special cases of this ensemble. We
interpolate between these cases from a region where satisfiability can be
typically decided for all connectivities in polynomial time to a region where
deciding satisfiability is hard, in some interval of connectivities. We derive
several rigorous results in the first region, and develop the
one-step--replica-symmetry-breaking cavity analysis in the second one. We
discuss the prediction for the transition between the almost surely satisfiable
and the almost surely unsatisfiable phase, and other structural properties of
the phase diagram, in light of cavity method results.Comment: 30 pages, 12 figure
Construction of optimal spectral methods in phase retrieval
We consider the phase retrieval problem, in which the observer wishes to
recover a -dimensional real or complex signal from the
(possibly noisy) observation of , in which
is a matrix of size . We consider a
\emph{high-dimensional} setting where with , and a large class of (possibly correlated) random matrices
and observation channels. Spectral methods are a powerful tool
to obtain approximate observations of the signal which can
be then used as initialization for a subsequent algorithm, at a low
computational cost. In this paper, we extend and unify previous results and
approaches on spectral methods for the phase retrieval problem. More precisely,
we combine the linearization of message-passing algorithms and the analysis of
the \emph{Bethe Hessian}, a classical tool of statistical physics. Using this
toolbox, we show how to derive optimal spectral methods for arbitrary channel
noise and right-unitarily invariant matrix , in an automated
manner (i.e. with no optimization over any hyperparameter or preprocessing
function).Comment: 14 pages + references and appendix. v2: Version updated to match the
one accepted at MSML 2021. v3: Adding a reference to a previous work
mentioning marginal stability and its connection to Bayes-optimalit
Effect of gender on strength gains after isometric exercise coupled with electromyographic biofeedback in knee osteoarthritis: A preliminary study
AbstractObjectiveThe objective of this trial was to evaluate the effect of gender on strength gains after five week training programme that consisted of isometric exercise coupled with electromyographic biofeedback to the quadriceps muscle.Materials and methodsForty-three (20 men and 23 women) patients with knee osteoarthritis (OA), were placed into two groups based on their gender. Both groups performed isometric exercise coupled with electromyographic biofeedback for five days a week for five weeks.ResultsBoth groups reported gains in muscle strength after five week training. However, the difference was found to be statistically insignificant between the two groups (P=0.224).ConclusionThe results suggest that gender did not affect gains in muscle strength by isometric exercise coupled with electromyographic biofeedback in patients with knee OA
The number of matchings in random graphs
We study matchings on sparse random graphs by means of the cavity method. We
first show how the method reproduces several known results about maximum and
perfect matchings in regular and Erdos-Renyi random graphs. Our main new result
is the computation of the entropy, i.e. the leading order of the logarithm of
the number of solutions, of matchings with a given size. We derive both an
algorithm to compute this entropy for an arbitrary graph with a girth that
diverges in the large size limit, and an analytic result for the entropy in
regular and Erdos-Renyi random graph ensembles.Comment: 17 pages, 6 figures, to be published in Journal of Statistical
Mechanic
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