920 research outputs found
Enhanced suppresion of localization in a continuous Random-Dimer Model
We consider a one-dimensional continuous (Kronig-Penney) extension of the
(tight-binding) Random Dimer model of Dunlap et al. [Phys. Rev. Lett. 65, 88
(1990)]. We predict that the continuous model has infinitely many resonances
(zeroes of the reflection coefficient) giving rise to extended states instead
of the one resonance arising in the discrete version. We present exact,
transfer-matrix numerical calculations supporting, both realizationwise and on
the average, the conclusion that the model has a very large number of extended
states.Comment: 10 pages, 3 Figures available on request, REVTeX 3.0, MA/UC3M/1/9
Image sequence analysis for emerging interactive multimedia services - The European COST 211 framework
Cataloged from PDF version of article.Flexibility and efficiency of coding, content extraction,
and content-based search are key research topics in
the field of interactive multimedia. Ongoing ISO MPEG-4 and
MPEG-7 activities are targeting standardization to facilitate such
services. European COST Telecommunications activities provide
a framework for research collaboration. COST 211bis and COST
211ter activities have been instrumental in the definition and
development of the ITU-T H.261 and H.263 standards for videoconferencing
over ISDN and videophony over regular phone
lines, respectively. The group has also contributed significantly
to the ISO MPEG-4 activities. At present a significant effort
of the COST 211ter group activities is dedicated toward image
and video sequence analysis and segmentation—an important
technological aspect for the success of emerging object-based
MPEG-4 and MPEG-7 multimedia applications. The current
work of COST 211 is centered around the test model, called
the Analysis Model (AM). The essential feature of the AM is
its ability to fuse information from different sources to achieve
a high-quality object segmentation. The current information
sources are the intermediate results from frame-based (still) color
segmentation, motion vector based segmentation, and changedetection-based
segmentation. Motion vectors, which form the
basis for the motion vector based intermediate segmentation, are
estimated from consecutive frames. A recursive shortest spanning
tree (RSST) algorithm is used to obtain intermediate color and
motion vector based segmentation results. A rule-based region
processor fuses the intermediate results; a postprocessor further
refines the final segmentation output. The results of the current
AM are satisfactory; it is expected that there will be further
improvements of the AM within the COST 211 project
Effects of functional strength training on functional movement and balance in middle-aged adults
Functional movement deficiencies cause falls and injuries in adults. Functional strength training (FST) is emerging as a new training method for athletes, middle-aged and older adults, to improve functional movement: The present study was conducted in order to investigate the effects of FST on balance and functional movement in healthy and independent middle-aged adults. The sample for this study consisted of 46 physically active individuals (24 female and 22 male). A total of 46 subjects were divided based on randomly into the functional strength training (FST) group (n = 26) aged: 51.55 ± 3.73 years; height: 168.69 ± 8.8 cm; body mass: 75.88 ± 12.18; and traditional strength training (TST) group (n = 20) age: 52.85 ± 4.01; height: 166.9 ± 9.98; body mass: 76.15 ± 10.45. Each group performed 24 sessions of a training protocol three-time a week. The functional movement was assessed using the functional movement screen (FMS) protocol. Balance performance was determined by using the balance error scoring system (BESS). Bodyweight and body fat ratio were measured using bioelectric impedance. There was a significant statistical difference between FMS total scores after an eight-week FST in the FST group. After the intervention, the functional strength group tended to have significantly better balance control than the traditional strength group (p = 0.01). Statistically, significant differences were observed between pre-test and post-test in the intervention group on BMI, body fat, and body mass (p = 0.01). There were not found significant differences in balance control and FMS score in TST group. As a result of this study, FST positively affected the FMS total score and balance performance in middle-aged adults. Early detections of the deficiencies in functional movement and balance in the middle ages may reduce the risk of insufficiency and fall in adults through targeted functional strength training intervention
“Bibliostory—Educational Comic Stories.” A Social Constructivist Approach to Media and Information Literacy Education for Children and Adolescents
Our paper presents a theoretical background for a Polish comic book “Bibliostory—educational comic stories” (Pl. Bibliostory—edukacyjne historie komiksowe). The comic targets children between 9 and 12 years of age and youths from 13 to 16 years of age. Each story illustrates one issue, such as information searching, organization of information, plagiarism, and information problem solving strategy. Bibliostory is based on two constructivist pedagogical concepts: the zone of proximal development (ZPD) and case-based learning/teaching. These concepts, on application level, are first of all associated with designing educational situations and relationships between teachers and students (educators and learners). The aim of our paper is to present the possibilities of application of these concepts in the educational comic books. We describe the general assumptions of two concepts, then we focus on elements applied in Bibliostory project. We also provide a review of literature on the educational potential of comic books.Zuza Wiorogórska’s work was carried out during her stay as the visiting scholar at the University of California, Berkeley, thanks to a scholarship from the Kosciuszko Foundation. Ewa Rozkosz’s work was carried out thanks to the grant awarded by the Faculty of Education of the University of Lower Silesia for the project “Społeczno-kulturowe podejście w projektowaniu materiałów edukacyjnych na potrzeby edukacji medialnej I inforamacyjnej dzieci i młodzieży na przykładzie »Bibliostory«” (nr 05/ WGW/dok/2016)
A novel enzymatically-mediated drug delivery carrier for bone tissue engineering applications: combining biodegradable starch-based microparticles and differentiation agents
In many biomedical applications, the performance
of biomaterials depends largely on their degradation
behavior. For instance, in drug delivery applications, the
polymeric carrier should degrade under physiological
conditions slowly releasing the encapsulated drug. The aim
of this work was, therefore, to develop an enzymaticmediated
degradation carrier system for the delivery of
differentiation agents to be used in bone tissue engineering
applications. For that, a polymeric blend of starch with
polycaprolactone (SPCL) was used to produce a microparticle
carrier for the controlled release of dexamethasone
(DEX). In order to investigate the effect of enzymes on the
degradation behavior of the developed system and release
profile of the encapsulated osteogenic agent (DEX), the
microparticles were incubated in phosphate buffer solution
in the presence of a-amylase and/or lipase enzymes (at
physiological concentrations), at 37 C for different periods
of time. The degradation was followed by gravimetric
measurements, scanning electron microscopy (SEM) and
Fourier transformed infrared (FTIR) spectroscopy and the
release of DEX was monitored by high performance liquid
chromatography (HPLC). The developed microparticles
were shown to be susceptible to enzymatic degradation, as observed by an increase in weight loss and porosity with
degradation time when compared with control samples
(incubation in buffer only). For longer degradation times,
the diameter of the microparticles decreased significantly
and a highly porous matrix was obtained. The in vitro
release studies showed a sustained release pattern with
48% of the encapsulated drug being released for a period of
30 days. As the degradation proceeds, it is expected that
the remaining encapsulated drug will be completely
released as a consequence of an increasingly permeable
matrix and faster diffusion of the drug. Cytocompatibility
results indicated the possibility of the developed microparticles
to be used as biomaterial due to their reduced
cytotoxic effects
The relationship of the parotid duct to the buccal and zygomatic branches of the facial nerve; an anatomical study with parameters of clinical interest
There have been studies concerning the protection of the facial nerve during plastic surgery intended for the parotid gland. The close relationship between the parotid duct and the buccal and zygomatic branches of the facial nerve is studied here. The dissections were performed on 10 fixed cadavers at the Anatomy Dissection Laboratory of Ankara University in 2004. The reference points used for surgery of this region were taken into consideration as the landmarks for morphometric measurements.
In 7 of the cases the zygomatic branch was double and in 3 it was single. In
4 of the 7 cases with a double zygomatic branch both superior and inferior branches crossed the parotid duct. In the remaining 3 cases the superior branches of the zygomatic nerve coursed through the zygomatic major and minor muscles. In 9 of all the cases the zygomatic branch of the facial nerve crossed the duct anteriorly and
in one it did so posteriorly (case 10). The buccal branch was single in 4 of the cases and double in 6. Among these one of the most precise measurements was the
distance between the lateral canthus and the intersection point of the zygomatic
branch and the duct with a coefficient of variation of 9.9%. With the use of this reliable measurement the intersection point of the zygomatic branch and the duct may be estimated to be within 5.16 ± 1.01 centimetres of the lateral canthus. Facial nerve paralysis is the most important complication of superficial face surgery and the
anatomy of this region must thus be taken into detailed consideration by surgeons
A universal workflow for creation, validation, and generalization of detailed neuronal models
\ua9 2023 The Author(s). Detailed single-neuron modeling is widely used to study neuronal functions. While cellular and functional diversity across the mammalian cortex is vast, most of the available computational tools focus on a limited set of specific features characteristic of a single neuron. Here, we present a generalized automated workflow for the creation of robust electrical models and illustrate its performance by building cell models for the rat somatosensory cortex. Each model is based on a 3D morphological reconstruction and a set of ionic mechanisms. We use an evolutionary algorithm to optimize neuronal parameters to match the electrophysiological features extracted from experimental data. Then we validate the optimized models against additional stimuli and assess their generalizability on a population of similar morphologies. Compared to the state-of-the-art canonical models, our models show 5-fold improved generalizability. This versatile approach can be used to build robust models of any neuronal type
scAmpi—A versatile pipeline for single-cell RNA-seq analysis from basics to clinics
Single-cell RNA sequencing (scRNA-seq) has emerged as a powerful technique to decipher tissue composition at the single-cell level and to inform on disease mechanisms, tumor heterogeneity, and the state of the immune microenvironment. Although multiple methods for the computational analysis of scRNA-seq data exist, their application in a clinical setting demands standardized and reproducible workflows, targeted to extract, condense, and display the clinically relevant information. To this end, we designed scAmpi (Single Cell Analysis mRNA pipeline), a workflow that facilitates scRNA-seq analysis from raw read processing to informing on sample composition, clinically relevant gene and pathway alterations, and in silico identification of personalized candidate drug treatments. We demonstrate the value of this workflow for clinical decision making in a molecular tumor board as part of a clinical study
- …
