julilili42/papers huggingface dataset:
Visual tracking and following of a quadrocopter by another quadrocopter
2012-10-01

We present a follow-the-leader scenario with a system of two small low-cost quadrocopters of different types and configurations. The leader is a Parrot AR.Drone which is controlled by an iPad App utilizing the visual odometry provided by the quadrocopter and pilots it autonomously. The follower is an Asctec Hummingbird which is controlled by an onboard 8-bit microcontroller. Neither communication nor external sensors are required. A custom-built pan/tilt unit and the camera of a Nintendo Wii remote tracks a pattern of infrared lights and allows for online pose estimation. A base station allows for monitoring the behavior but is not required for autonomous flights. Our efficient solution of the perspective-3-point problem allows for estimating the pose of the camera relative to the pattern in six degrees of freedom at a high frequency on the microcontroller. The presented experiments include a scenario in which the follower follows the leader with a constant distance of two meters flying different shapes in narrow, GPS-denied indoor environment.
A new feature detector and stereo matching method for accurate high-performance sparse stereo matching
2012-10-01

Hardware platforms with limited processing power are often incapable of running dense stereo analysis algorithms at acceptable speed. Sparse algorithms provide an alternative but generally lack in accuracy. To overcome this predicament, we present an efficient sparse stereo analysis algorithm that applies a dense consistency check, leading to accurate matching results. We further improve matching accuracy by introducing a new feature detector based on FAST, which exhibits a less clustered feature distribution. The new feature detector leads to a superior performance of our stereo analysis algorithm. Performance evaluation shows that the proposed stereo matching system achieves processing rates above 200 frames per second on a commodity dual core CPU, and faster than video frame-rate processing on a low-performance embedded platform. The stereo matching results prove to be superior to those obtained with ordinary sparse matching algorithms.
A brain-robot interface for studying motor learning after stroke
2012-10-01

Despite intensive efforts, no significant benefit of rehabilitation robotics in post-stroke motor-recovery has yet been demonstrated in large-scale clinical trials. The present work is based on the premise that future advances in rehabilitation robotics require an enhanced understanding of the neural processes involved in motor learning after stroke. We present a system that combines a Barret WAMTMseven degree-of-freedom robot arm with neurophysiological recordings for the purpose of studying post-stroke motor learning. We used this system to conduct a pilot study on motor learning during reaching movements with two stroke patients. Preliminary results indicate that pre-trial brain activity in ipsilesional sensorimotor areas may be a neural correlate of the current state of motor learning. These results are discussed in terms of their relevance for future rehabilitation strategies that combine rehabilitation robotics with real-time analyses of neuro-physiological recordings.
Path following with passive UHF RFID received signal strength in unknown environments
2012-10-01

We present a novel approach incorporating a combination of Radio-Frequency Identification (RFID) and odometry information into the motion control of a mobile robot for the purpose of path following in unknown environments. Our method utilizes RFID measurements as landmarks and makes the mobile robot autonomously follow a path that was previously recorded in a manual training phase. The approach needs no prior information about RFID sensor models, the distribution and positioning of the tags nor does it require a map of the environment. Particularly, it is adaptive to different reader power levels and various tag densities, which have a major impact on RFID performance. Extensive experiments with a SCITOS G5 robot in different environments like a library, a supermarket and hallways confirm the effectiveness of our algorithm.
Evaluation of the KIT/stem cell factor axis in renal tumours.
2012-10-01

Simultaneous expression of SCF and KIT in renal tumours, which seems to undergo a shift from the cytoplasm to the cell membrane, suggests paracrine and autocrine mechanisms in KIT activation, with different, as yet unknown, regulatory mechanisms in the different tumour entities.
Soil biotic impact on plant species shoot chemistry and hyperspectral reflectance patterns
2012-10-01

Summary Recent studies revealed that plant–soil biotic interactions may cause changes in above‐ground plant chemistry. It would be a new step in below‐ground–above‐ground interaction research if such above‐ground chemistry changes could be efficiently detected. Here we test how hyperspectral reflectance may be used to study such plant–soil biotic interactions in a nondestructive and rapid way. The native plant species J acobaea vulgaris and J acobaea erucifolius , and the exotic invader S enecio inaequidens were grown in different soil biotic conditions. Biomass, chemical content and shoot reflectance between 400 and 2500 nm wavelengths were determined. The data were analysed with multivariate statistics. Exposing the plants to soil biota enhanced the content of defence compounds. The highest increase (400%) was observed for the exotic invader S . inaequidens . Chemical and spectral data enabled plant species to be classified with an accuracy &gt; 85%. Plants grown in different soil conditions were classified with 50–60% correctness. Our data suggest that soil microorganisms can affect plant chemistry and spectral reflectance. Further studies should test the potential to study plant–soil biotic interactions in the field. Such techniques could help to monitor, among other things, where invasive exotic plant species develop biotic resistance or the development of hotspots of crop soil diseases.
Preparation and investigation of the A-site and B-site terminated SrTiO3(001) surface: A combined experimental and theoretical x-ray photoelectron diffraction study
2012-10-01

We have investigated surface composition, structure, and termination of SrTiO3(001) samples (STO) following typical steps of standard ex situ and in situ preparation procedures by performing x-ray photoelectron spectroscopy (XPS) and x-ray photoelectron diffraction (XPD) experiments, and multiple scattering cluster (MSC) calculations. XPS has confirmed the presence of Sr2+, Ti4+, and O2-related to STO. Well-developed diffraction features have been observed in all XPD polar scans demonstrating the good structural ordering of the investigated surfaces. In order to permit a detailed comparison of XPD experiment and theory, we have especially taken care of effects due to the angular dependent instrument function by applying a new ratio procedure. Thus, we achieved a very good agreement between results of MSC calculations and experimental angular distributions. A fingerprint region has been identified in Sr3d polar scans, which has exhibited both evident dependencies on surface preparation steps in the experiments and clear sensitivity to surface termination in the theoretical modeling. In this manner, we have been able to describe as-received samples and in situ-treated samples as being TiO2- and SrO-terminated, respectively. Standard buffered hydrofluoric acid-treated samples turned out to be mostly TiO2-terminated but with a non-negligible admixture of different, likely SrO-type termination.
Human melanoma cells in the rhombencephalon of the chick embryo: a novel model for brain metastasis
2012-10-01

Abstract Malignant melanoma has the highest propensity to metastasize to the brain of all primary neoplasms in adults. Here, we describe invasive growth and the development of melanoma metastases from suspensions of human melanoma cells in the brain of the chick embryo. Patient‐derived melanoma cells and established melanoma cell lines were injected into the rhombencephalic brain vesicle of the two‐day‐chick embryo. After 48 and 96 h, tumor formation was studied in serial paraffin sections with melanoma‐specific HMB 45 and human‐specific MIB1 proliferation markers. The majority of the cells injected into the embryonic liquor cavity perished. Only melanoma cells in newly formed aggregates or when attached to the dorsal roof plate escaped apoptosis. Local invasion occurred not in the ventral differentiating neural epithelium but only in the roof plate. Although after 48 h melanoma cells invaded the rhombencephalic roof plate profusely at both sides, after 96 h typically one large tumor developed in the midline between roof plate and the dorsal surface epithelium. From the tumor, single cells invaded the mesenchyme and blood vessels. Cell lines with different invasive properties retained their graded invasive behaviour. Maximally invasive cells formed continuous tracks via vessels and along nerve fibres. The central tumor in the roof plate of the chick embryo rhombencephalon resembles a metastatic nodule in the patients with melanoma. Penetration of the roof plate epithelium, tumor formation and invasion of surrounding tissues by single cells can reliably be reproduced. The chick embryo model can be used for molecular studies of early phases of melanoma brain metastasis.
Incremental Large Scale 3D Reconstruction
2012-10-01

In this paper, we describe our incremental large scale 3D reconstruction approach. The input for the algorithm is a set of overlapping sub-models, reconstructed from smaller sets of calibrated images. The output of the algorithm is a set of transformation matrices, that are used to bring sub-models to the common coordinate system. All sub-models transformed by their corresponding matrices form a single large model in a global coordinate system. The interesting property of the proposed approach is the possibility of in- cremental construction of the final composite model. The data collection, camera calibration, and computation 3D of sub-models can be performed independently by many users. Furthermore, adding new sub-models can improve overall reconstruction quality.
Biomass explains the intensity of facilitative – not competitive – interactions: three intraspecific tests with annuals
2012-10-01

Abstract. Despite efforts to discern the role of plant size in resource competition, the circumstances under which size-dependent plant-plant interactions occur are still unclear. The traditional assumption is that competition intensifies with increasing neighbour size. However, recent studies suggest that the size (biomass) dependence of competitive interactions is strongest at very low biomass levels and becomes negligible after a certain threshold neighbour biomass has been reached. We searched for the generality of such patterns for three common annual plant species in Israel. We monitored target and neighbour biomass along their entire lifecycle using an even-aged, intraspecific and intrapopulation competition screenhouse experiment under water-limited conditions. For all focal species, neighbour presence had a net negative effect on vegetative biomass at harvest. However, this was not explained by increasing neighbour biomass over time, as a consistent pattern of size-dependent facilitative, rather than competitive, interactions was observed at all life stages. We explain these observations in terms of co-occurring aboveground facilitation and dominant belowground competition for water. Since our findings are the first of their kind and contradict theoretical predictions of biomass dependence of net negative interactions, we advocate further experiments addressing size dependence in interactions among plants. In particular, theoretical models addressing size dependence of positive interactions must be developed.
Risk stratification after myocardial infarction: it is time for intervention
2012-10-01

This editorial refers to ‘Non-invasive risk stratification for sudden cardiac death by heart rate turbulence and microvolt T-wave alternans in patients after myocardial infarction’ by V. Sulimov et al ., on page 1786 Despite significant advances in interventional and pharmacological therapies, late mortality after acute myocardial infarction (MI) is still high. Approximately 50% of cardiovascular deaths after MI occur suddenly and are potentially preventable by prophylactic implantation of a cardioverter-defibrillator (ICD). In recent decades, substantial efforts have been made to identify high-risk patients who may benefit from prophylactic therapy. While initial risk stratification strategies guiding ICD therapy were based on the comprehensive electrophysiological testing in highly selected subgroups of patients, a revolutionary concept was proposed in 2002, when Moss et al. 1 presented the results of MADIT-2 (Multicentre Automatic Defibrillator Implantation Trial). In contrast with all previous attempts, MADIT-2 used the finding of a reduced left ventricular ejection fraction (LVEF) as the single selection criterion for prophylactic ICD-implantation. In terms of efficacy and effectiveness, the MADIT-2 criterion was a great success. Subsequent trials confirmed the concept of prophylactic ICD-implantation in patients with impaired LVEF, and later economic analyses verified the cost-effectiveness of this approach. However, when looking from an epidemiological point of view at the global impact of ICD ...
Direct 3D-collaboration with Face2Face - implementation details and application concepts
2012-10-01

In this paper we present a system for video based remote collaboration in stereoscopic 3D that supports multi-touch interaction. The presented system seamlessly integrates shared virtual 3D-material into a video conference application. The system utilizes a calibrated stereo camera setup to capture the collaborating users through a semi-transparent holographic screen. The resulting novel form of remote communication is analyzed for its practicability in varying application scenarios. For this, the impact of preconditions of different scenarios on the overall performance of the system and implications on its design are evaluated. Furthermore, we propose techniques to achieve telepresence in those scenarios by improving image quality and suggest an approach for automatic camera calibration to make the installation and maintenance of Face2Face feasible.
CLIN-NEURO/MEDICAL ONCOLOGY
2012-10-01

PURPOSE: This study was performed to evaluate the incidence of seizures with its implications on disease progression and the diagnostic value of post-ictal magnetic resonance images (MRI) during the management of highgrade gliomas (HGGs).PATIENTS AND METHODS: A total of 406 consecutive patients with newly diagnosed HGGs were retrospectively reviewed.The incidence of seizure attacks during the management was investigated.In patients who experienced a seizure, the causality between seizures and disease progression was assessed by pre-ictal, post-ictal (,1 month), and follow-up (,3 months) MRI.RESULTS: After a mean follow-up of 21.9 months (range, 0.1 -88.3), seizure attacks developed in 127 patients (31%).Of the 127 patients, radiological progression at the post-ictal MRI was found in 83 patients (65%) and the follow-up MRI confirmed progression in 79 patients (62%).However, other 4 patients (3%) were shown to be progression-free.Among those without radiological progression at the post-ictal MRI, the follow-up MRI confirmed progression-free in 31 patients (24%); however, 13 patients (10%) revealed eventual progression.In the patients with a seizure, absence of preoperative seizure (p 1⁄4 0.003), , 95% tumor resection (p 1⁄4 0.001), and pre-ictal Karnofski Performance Scale score ≤ 70 (p 1⁄4 0.025) were significantly associated with disease progression.CONCLUSION: During the management of HGG, 31% of patients experienced seizures; of these patients, 72% harbored progressive disease.The post-ictal MRI is useful for detecting disease progression; however, there are pitfalls.Clinical settings should be considered together for diagnosing disease progression in patients with seizures.NO-03.
Autonomous failure detection and multimodal sensor fusion in a modular arm model
2012-10-01

When soft robots act in new or unforeseen situations, uncertainty becomes a major challenge. Sensors might fail and the forward kinematics might become faulty if limbs are deformed. To meet this challenge, we propose a model that uses additional sensors in different modalities and provides a highly modular body model which can be easily adapted. Longterm sensor-blackout is covered by usage of multiple sensors in different modalities, while short term sensor-blackout is covered by the maintenance of state representations over time and the inclusion of a full forward and inverse model suitable for prediction and simulation. Even more, as the state is represented redundantly in multiple modalities, the system compares the estimates to detect changes in sensor noise or even sensor offsets and discards failing sensors. Finally, the highly modularized architecture of our representation simplifies the adaptation of the body model.
Analysis-by-Synthesis Texture Reconstruction
2012-10-01

Within the recent decade, reconstruction of real world scenes gained continuously more importance. For realistic reconstructions both, the geometry and the textures, are important. We present a general algorithm for reconstructing textures from an image sequence of flat patches, where the angle between the patch normal and the view direction of the observing cameras could be close to 90. In such case the image of the patch in the camera frames collapses to just a few pixel rows, and most of the algorithms used today will fail. The method we present uses an analysis-by-synthesis approach for reconstructing the texture by combining information from all input images. In each step, the previously reconstructed texture is tested by using it for rendering artificial input images which are then compared to the real ones. If they are not equal, we use the difference for calculating an update to the existent texture. For this update we employ a back projection approach that produces excellent reconstructions in only a few iteration steps.
FEASIBILITY OF HEAVY METALS REMOVAL FROM COMPOST BY BIOSURFACTANT
2012-10-01

Biosurfactants have the ability to form heavy metal complexes and clean up heavy metal contaminated soils. In this work, a biosurfactant producing bacterium (Bacillus spp.) isolated from compost and Pseudomonas aeuroginosa ATCC3027 were cultured in whey in order to produce biosurfactant. Compost samples were leached by supernatant of mentioned strains. Total amount of Pb, Ni, Cr, Cd, Zn, Cu and Mn in samples were measured before and after treatment was measured. It was revealed that supernatant of P. aeuroginosa ATCC 3027 removed 52, 49, 60, 33, 25, 32 and 22% of Pb, Ni, Cr, Cd, Zn, Cu and Mn respectively. Heavy metal removal by supernatant of strain B was 45, 39, 42, 33, 40, 41 and 29% for above mentioned metals; respectively. These results indicate the potential of the biosurfactants as leaching agents for heavy metal removal from compost.
Pharmacological stroke prevention: antithrombotic drugs
2012-10-01

Ischemic stroke is the most serious and devastating complication of atrial fibrillation. Dose-adjusted oral anticoagulation is highly efficient in reducing the risk for ischemic stroke in atrial fibrillation patients with risk factors and is superior to antiplatelet agents. New thrombin antagonists and factor Xa inhibitors have recently become available, which offer a better risk/benefit ratio and wider therapeutic margins without the need for coagulation controls.
Motion of charged particles and quasinormal modes around the magnetically and tidally deformed black hole
2012-10-02

Here we consider two phenomena in the vicinity of a black hole deformed by\\nthe tidal gravitational force of surrounding matter and by a strong magnetic\\nfield: equatorial motion of charged particles and the decay of a test scalar\\nfield. We were able to analyze both phenomena with analytical and simple\\nnumerical tools, which was unexpected given the low symmetry of the system. We\\nshow that both the tidal gravitational force and the magnetic field strongly\\nenhance the release of the binding energy for the matter spiralling into the\\nblack hole. In the presence of the magnetic field, the left and right handed\\nrotations of charged particles are not equivalent and for sufficiently large\\n there are stable anti-Larmor orbits very close to the event horizon,\\nalthough Larmor orbits are only stable at some distance from the black hole.\\nThe larger the tidal force, the closer the innermost stable orbit to the black\\nhole for both types of rotation. It was also shown that the real oscillation\\nfrequencies of the characteristic quasinormal modes are considerably suppressed\\nby the tidal force.\\n
Organozinc‐ and Imidazole‐Modified Periodic Mesoporous Organosilicas by Means of Molecular Grafting
2012-10-02

Abstract Cagelike cubic periodic mesoporous organosilicas PMO[SBA‐1] with various pore diameters and distorted hexagonal PMO[MCM‐41] as supports were synthesized by using 1,2‐bis(triethoxysilyl)ethane as an organosilica source, and a mixture of binary surfactants C 18‐3‐1 and C 18 TABr as a template under basic conditions. Surface silanol group populations (0.72–1.41 mmol g –1 ) of PMO[SBA‐1] and PMO[MCM‐41] were determined by carbon elemental analysis from surface silylation. Diethylzinc was immobilized on PMOs to afford ZnEt x @PMO[SBA‐1]/[MCM‐41] with various Zn loading (1.60–2.38 mmol g –1 ), which depended on surface silanol population of the corresponding PMOs and the number of cleaved siloxane bonds. The surface ethyl groups coordinated to zinc can be exchanged readily by the 4‐methyl‐2,6‐dibutylphenoxy or di‐ tert ‐butylsilanoxy group to give various organozinc‐modified PMO materials ZnR x @PMO[SBA‐1]/[MCM‐41] (herein, R represents 4‐methyl‐2,6‐dibutylphenoxy and di‐ tert ‐butylsilanoxy groups). Moreover, N ‐(3‐triethoxysilylpropyl)‐4,5‐dihydroimidazole was grafted onto the PMO surfaces to afford hybrid materials Si(OEt) y (CH 2 ) 3 (imidazole)@PMO[SBA‐1]/[MCM‐41] with the amount of functional groups ranging from 0.36 to 0.70 mmol g –1 . The coordination behavior of the surface functional groups with diethylzinc was investigated, and possible coordination modes were hypothesized. All materials were characterized by infrared spectroscopy, N 2 physisorption, and elemental analysis. Representative 1 H and 13 C NMR spectra of a selected organozinc‐/imidazole‐functionalized PMO were recorded to corroborate the proposed surface species. This work presents a versatile approach to the fabrication of multiple surface species that coexist on a support for exploiting the potential application of novel heterogeneous catalysts.
Lithocholic acid is an endogenous inhibitor of MDM4 and MDM2
2012-10-03

The proteins MDM2 and MDM4 are key negative regulators of the tumor suppressor protein p53, which are frequently upregulated in cancer cells. They inhibit the transactivation activity of p53 by binding separately or in concert to its transactivation domain. MDM2 is also a ubiquitin ligase that leads to the degradation of p53. Accordingly, MDM2 and MDM4 are important targets for drugs to inhibit their binding to p53. We found from in silico screening and confirmed by experiment that lithocholic acid (LCA) binds to the p53 binding sites of both MDM2 and MDM4 with a fivefold preference for MDM4. LCA is an endogenous steroidal bile acid, variously reported to have both carcinogenic and apoptotic activities. The comparison of LCA effects on apoptosis in HCT116 p 53 +/+ vs. p 53 -/- cells shows a predominantly p53-mediated induction of caspase-3/7. The dissociation constants are in the μM region, but only modest inhibition of binding of MDM2 and MDM4 is required to negate their upregulation because they have to compete with transcriptional coactivator p300 for binding to p53. Binding was weakened by structural changes in LCA, and so it may be a natural ligand of MDM2 and MDM4, raising the possibility that MDM proteins may be sensors for specific steroids.