Topographical evaluation of the phenotype of spontaneous behaviour in mice with targeted gene deletion of the D1A dopamine receptor: paradoxical elevation of grooming syntax

The phenotype of spontaneous behaviour in mice with targeted gene deletion of the DIA dopamine receptor was investigated topographically. Via direct visual observation, individual elements of behaviour were resolved and quantified using an ethologically-based, rapid time-sampling behavioural check-list procedure. Relative to wildtypes (D1A+/+), D1A-null (-/-) mice evidenced over initial exploration significant reductions in rearing free, sifting and chewing, but significant increases in locomotion, grooming and intense grooming. Sniffing and rearing to a wall habituated less readily in D1A-null mice such that these behaviours occurred subsequently to significant excess: increases in locomotion were persistent. The ethogram of spontaneous behaviour in D1A-null mice was characterised by neither 'hypoactivity' or 'hyperactivity' but, rather, by prominent topographical shifts between individual elements of behaviour that could not be encapsulated by either term. Given the substantial body of evidence that grooming and particularly intense grooming constitute the most widely accepted behavioural index of D1-like receptor function, the elevation of such behaviour in D1A-null mice was paradoxical; it may reflect (over)compensatory processes subsequent to developmental absence of D1A receptors and/or the involvement of a D1-like receptor other than/additional to the D1A subtype.     

Quadrocopter Hovering Using Position-estimation Information from Inertial Sensors and a High-delay Video System

The requirement that mobile robots become independent of external sensors, such as GPS, and are able to navigate in an environment by themselves, means that designers have few alternative techniques available. An increasingly popular approach is to use computer vision as a source of information about the surroundings. This paper presents an implementation of computer vision to hold a quadrocopter aircraft in a stable hovering position using a low-cost, consumer-grade, video system. However, such a system is not able to stabilize the aircraft on its own and must rely on a data-fusion algorithm that uses additional measurements from on-board inertial sensors. Special techniques had to be implemented to compensate for the increased delay in the closed-loop system with the computer vision system, i.e., video timestamping to determine the exact delay of the vision system and a slight modification of the Kalman filter to account for this delay. At the end, the validation results of the proposed filtering technique are presented along with the results of an autonomous flight as a proof of the proposed concept.     

Spincopter Wing Design and Flight Control

This paper presents dynamical properties of an unmanned aerial vehicle (UAV), called spincopter. The vehicle structure is based on two wings that are forced in rotation (spinning) by propulsion system formed of two propellers. Based on devised dynamical model, that reveals inherent stability of the vehicle, composition of control algorithms for vertical and horizontal movement is proposed. Due to the specific configuration of the propulsion system, movement in horizontal direction is produced by pulsations in rotational speed of propulsion motors. An analysis of influence that such a configuration has on the vehicle dynamics is given. Finally, design recommendations for rotational wings are elaborated, based on extensive simulations of spincopter by using X-Plane® software package.     

Computing quadratic entropy in evolutionary trees

We note here that quadratic entropy, a measure of biological diversity introduced by C.R. Rao, is a variant of the weighted Wiener index, a graph invariant intensively studied in mathematical chemistry. This fact allows us to deduce some efficient algorithms for computing the quadratic entropy in the case of given tip weights, which may be useful for community biodiversity measures. Furthermore, on ultrametric phylogenetic trees, the maximum of quadratic entropy is a measure of pairwise evolutionary distinctness in conservation biology, introduced by S. Pavoine. We present an algorithm that maximizes this quantity in linear time, offering a significant improvement over the currently used quadratic programming approaches.     

Copolymerization of α-methylstyrene with N-alkylmaleimides

Summary Alternating copolymers of -methylstyrene (-MeSt) with N-alkylmaleimides (RMI; R=Et, n-Pr, iso-Pr, n-Bu, n-Hex) were prepared in Calvet differential microcalorimeter under different monomer-to-monomer ratios in the feed using AIBN as initiator. The equilibrium constants of CT-complex monomers have low values: 0.02–0.05 L.mol^-1 but the mechanism of copolymerization indicates the participation of CT-complex. Equilibrium constants and rate of decomposition under the TGA conditions are not dependent on steric factors, but the rate of copolymerization decreases with the increase of bulkiness of alkyl substituent. In high conversion copolymerization it was observed that in the presence of an excess of homopolymerizable RMI, alternating copolymers are quantitatively formed prior to the formation of poly(RMI).Dedicated to Professor Dragutin Fle on the occasion of his 70th birthday     

Direct-laser writing of striplines on AgCl single crystals

Experiments on a localized and controlled photo-reduction of silver were carried out on a AgCl single crystal that was exposed to a UV-laser light. Basic parameters such as the peak power and the total energy dose were varied. The study showed that for a pulsed-laser beam with a high peak power (>20 W) the ablation threshold of the AgCl was exceeded, while at lower peak powers no ablation was detected, only a change in the surface morphology. The degree of silver reduction was monitored using EDS microanalyses of the irradiated trace and the crystal matrix. We showed that the formation of photo-reduced silver aggregates decreases the ablation threshold and that the formation of a continuous silver trace on the AgCl single crystal is possible when the power density of the laser beam is further reduced.     

A practical approach for clustering large data flows of malicious URLs

Over the last couple of years there has been a substantial increase of malicious attacks that are using the Internet as an infection vector. One solution to counter this problem is to implement a filter at the network connection level. Due to the large amount of data that has to be filtered in real-time, any practical approach has to consider both memory usage and performance limitations in order to deliver a fast response time. This paper presents a cloud-based mechanism that can be used to filter large amounts of network traffic with respect to both memory and response time limitations. The algorithms have been tested on data flows of more than 750 million of URLs/day. We will address different practical problems, such as storage, computation time and large data flow clustering. In the end we will also present different statistical results that we obtained over a period of 2 months.