New insights into the morphology of Trypanosoma cruzi reservosome

Reservosomes are late endosomes present only in members of the Schizotrypanum subgenus of the Trypanosoma genus and are defined as the site of storage of endocytosed macromolecules and lysosomal enzymes. They have been extensively described in Trypanosoma cruzi epimastigote: are bounded by a membrane unit, present an electron-dense protein matrix with electron-lucent lipid inclusions, being devoid of inner membranes. Here we performed a detailed ultrastructural analysis of these organelles using a variety of electron microscopy techniques, including ultrathin sectioning, uranyl acetate stained preparations, and freeze fracture, either in intact epimastigotes or in isolated reservosomes. New informations were obtained. First, both isolated and in situ reservosomes presented small profiles of inner membranes that are morphologically similar to the membrane surrounding the organelle. In uranyl acetate stained preparations, internal membrane profiles turned out to be longer than they appeared in ultrathin section images and traversed the organelle diameter. Internal vesicles were also found. Second, endocytosed cargo are not associated with internal vesicles and reach reservosomes on board of vesicles that fuse with the boundary membrane, delivering cargo directly into reservosome lumen. Third, electron-lucent bodies with saturated lipid core surrounded by a membrane monolayer and with unusual rectangular shape were also observed. Fourth, it was possible to demonstrate the presence of intramembranous particles on the E face of both internal vesicles and the surrounding membrane. Collectively, these results indicate that reservosomes have a complex internal structure, which may correlate with their multiple functions.     

Zusätzliche Stromwärmeverluste im Läufer von Induktionsmaschinen und ihre räumliche Verteilung bei Speisung mit U-Umrichtern im Blockbetrieb

Übersicht Die zusätzlichen Stromwärmeverluste im Läufer ändern sich bei einem Drehzahlstellantrieb je nach Betriebsweise des Umrichters beträchtlich. Im Blockbetrieb ist der Gesamtverlust kaum vom Lastzustand (Schlupf) abhängig. Im Synchronismus sind die Verluste jedoch ungleichmäßig auf die einzelnen Läuferstränge oder Stäbe verteilt. Die Maxima und Minima der Stabverluste stehen im Synchronismus etwa im Verhältnis 10:1 zueinander. Die Verluste in dem am stärksten beaufschlagten Läuferstab liegen nicht wesentlich niedriger als im Bemessungsbetrieb. Die gesamten zusätzlichen Stromwärmeverluste wachsen bei konstanter Speisefrequenz quadratisch mit der Spannung. Im Feldschwächbereich nehmen sie in Abhängigkeit von der Speisefrequenz ungefähr nach der Funktion 1/^1,52 ab.

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Additional rotor I²R-losses and their spatial distribution in three-phase windings respectively rotor bars of induction motors fed from six-step U-invertors

Contents Additional rotor I²R-losses in speed variable drives with induction motors change very strongly with the operation mode of the invertor. During block-operation the sum of these additional losses is nearly independent of the load (slip). But at synchronous speed the losses are distributed very unequally among the phase windings respectively the rotor bars. The ratio of maximum to minimum bar losses is approximately 10:1. The highest ohmic loss in a bar is nearly the same as the rated bar loss. The additional rotor I²R-losses change with the square of the voltage. In the field weakening range the losses drop with the frequency approximately following the function 1/^1,52.

     

Building 2D quasicrystals from 5-fold symmetric corannulene molecules

Nano Research - The formation of long-range ordered aperiodic molecular films on quasicrystalline substrates is a new challenge that provides an opportunity for further surface functionalization....     

Analysis of multi-agent activity using petri nets

This paper presents the use of place/transition petri nets (PNs) for the recognition and evaluation of complex multi-agent activities. The PNs were built automatically from the activity templates that are routinely used by experts to encode domain-specific knowledge. The PNs were built in such a way that they encoded the complex temporal relations between the individual activity actions. We extended the original PN formalism to handle the propagation of evidence using net tokens. The evaluation of the spatial and temporal properties of the actions was carried out using trajectory-based action detectors and probabilistic models of the action durations. The presented approach was evaluated using several examples of real basketball activities. The obtained experimental results suggest that this approach can be used to determine the type of activity that a team has performed as well as the stage at which the activity ended.     

SPC: Fast and Efficient Scalable Predictive Coding of Animated Meshes

Animated meshes are often represented by a sequence of static meshes with constant connectivity. Due to their frame-based representation they usually occupy a vast amount of bandwidth or disk space. We present a fast and efficient scalable predictive coding (SPC) scheme for frame-based representations of animated meshes. SPC decomposes animated meshes in spatial and temporal layers which are efficiently encoded in one pass through the animation. Coding is performed in a streamable and scalable fashion. Dependencies between neighbouring spatial and temporal layers are predictively exploited using the already encoded spatio-temporal neighbourhood. Prediction is performed in the space of rotation-invariant coordinates compensating local rigid motion. SPC supports spatial and temporal scalability, and it enables efficient compression as well as fast encoding and decoding. Parts of SPC were adopted in the MPEG-4 FAMC standard. However, SPC significantly outperforms the streaming mode of FAMC with coding gains of over 33%, while in comparison to the scalable FAMC, SPC achieves coding gains of up to 15%. SPC has the additional advantage over FAMC of achieving real-time encoding and decoding rates while having only low memory requirements. Compared to some other non-scalable state-of-the-art approaches, SPC shows superior compression performance with gains of over 16% in bit-rate.     

Liquid recirculation in microfluidic channels by the interplay of capillary and centrifugal forces

We demonstrate a technique to recirculate liquids in a microfluidic channel by alternating predominance of centrifugal and capillary forces to rapidly bring the entire volume of a liquid sample to within one diffusion length, δ, of the surface, even for sample volumes hundreds of times the product of δ and the geometric device area. This is accomplished by repetitive, random sampling of an on-disc sample reservoir to form a thin fluid layer of thickness δ in a microchannel, maintaining contact for the diffusion time, then rapidly exchanging the fluid layer for a fresh aliquot by disc rotation and stoppage. With this technique, liquid volumes of microlitres to millilitres can be handled in many sizes of microfluidic channels, provided the channel wall with greatest surface area is hydrophilic. We present a theoretical model describing the balance of centrifugal and capillary forces in the device and validate the model experimentally.     

Using jump-diffusion modeling for valuing real options in infrastructure projects

In infrastructure financed projects, in order to attract private investors, host governments often provide some guarantees. This paper develops a value model of minimum revenue guarantee with multiple-exercise real options under the impact of the emergency incident. The model is applied to infrastructure financed projects using the minimum revenue guarantee under simulation. The simulation results indicate that, before quantifying the value of the minimum revenue guarantee, it is necessary to forecast the jump degree and intensity of the emergency incident, as well as prevent and control risks arising from such emergencies. Otherwise, underestimation of the guarantee value will occur and the government will have to bear huge debt in this condition. We also analyze the dependence of the guaranteed value on the minimum guaranteed revenue level, initial revenue and number of exercise rights. For various conditions, the diagrams of the guaranteed value are also presented.     

SVM practical industrial application for mechanical faults diagnostic

A large percentage of the total induction motor failures are due to mechanical faults. It is well known that, machine’s vibration is the best indicator of its overall mechanical condition, and an earliest indicator of arising defects. Support vector machines (SVM) is also well known as intelligent classifier with strong generalization ability. In this paper, both, machine‘s vibrations and SVM are used together for a new intelligent mechanical fault diagnostic method. Using only one vibration sensor and only four SVM’s it was achieved improved results over the available approaches for this purpose in the literature. Therefore, this method becomes more attractive for on line monitoring without maintenance specialist intervention. Vibration signals turns out to occur in different directions (axial, horizontal or vertical) depending on the type of the fault. Thus, to diagnose mechanical faults it is necessary to read signals at various positions or use more them one accelerometer. From this work we also determined the best position for signals acquisition, which is very important information for the maintenance task.     

A semi-automatic strategy for achieving learning content and practice repurposing

The development of instructional content using Information Technologies is an expensive, time-consuming and complex process that requires new methodologies. It was in this context that the concept of Learning Objects (LOs) was proposed in order to promote reuse. However, this goal is not yet fully attained and new contributions to increase reuse are still welcome. Besides, if content is conveyed in LOs that are easier to reuse, they must be combined and sequenced in order to build more elaborated and complex content. This paper presents a strategy to deal with these problems based on the definition of small LOs here called Component Objects (COs). These COs are structured and combined according to a conceptual metamodel, which is the basis for the definition of conceptual schemas representing the existing material, including not only content but also practice. This strategy for searching, extracting, and sequencing COs, supports a teacher to better control the implementation of complex content, reducing errors in the authoring process. This approach includes a specification language and an algorithm for semi-automatic sequencing learning content and practice. Finally, a case study that shows the proposed approach and some results of using the algorithm are presented.