3,484 research outputs found
A developmental and genetic classification for malformations of cortical development: update 2012.
Malformations of cerebral cortical development include a wide range of developmental disorders that are common causes of neurodevelopmental delay and epilepsy. In addition, study of these disorders contributes greatly to the understanding of normal brain development and its perturbations. The rapid recent evolution of molecular biology, genetics and imaging has resulted in an explosive increase in our knowledge of cerebral cortex development and in the number and types of malformations of cortical development that have been reported. These advances continue to modify our perception of these malformations. This review addresses recent changes in our perception of these disorders and proposes a modified classification based upon updates in our knowledge of cerebral cortical development
Experimental determination of the frequency and field dependence of Specific Loss Power in Magnetic Fluid Hyperthermia
Magnetic nanoparticles are promising systems for biomedical applications and
in particular for Magnetic Fluid Hyperthermia, a promising therapy that
utilizes the heat released by such systems to damage tumor cells. We present an
experimental study of the physical properties that influences the capability of
heat release, i.e. the Specific Loss Power, SLP, of three biocompatible
ferrofluid samples having a magnetic core of maghemite with different core
diameter d= 10.2, 14.6 and 19.7 nm. The SLP was measured as a function of
frequency f and intensity of the applied alternating magnetic field H, and it
turned out to depend on the core diameter, as expected. The results allowed us
to highlight experimentally that the physical mechanism responsible for the
heating is size-dependent and to establish, at applied constant frequency, the
phenomenological functional relationship SLP=cH^x, with 2<x<3 for all samples.
The x-value depends on sample size and field frequency/ intensity, here chosen
in the typical range of operating magnetic hyperthermia devices. For the
smallest sample, the effective relaxation time Teff=19.5 ns obtained from SLP
data is in agreement with the value estimated from magnetization data, thus
confirming the validity of the Linear Response Theory model for this system at
properly chosen field intensity and frequency
Innerspec: Technical Report
In this report we describe āInnerSpecā, an approach for symmetric object detection that is based both on the com- putation of a symmetry measure for each pixel and on gra- dient information analysis. The symmetry value is obtained as the energy balance of the even-odd decomposition of an oriented square patch with respect to its central axis. Such an operation is akin to the computation of a row-wise con- volution in the midpoint. The candidate symmetry axes are then identified through the localization of peaks along the direction perpendicular to each considered angle. These axes are finally evaluated by computing the image gradient in their neighborhood, in particular checking whether the gradient information displays specular characteristics
Exploring the link between the corporate governance and efficiency of Italian water utilities
The present paper analyzes the linkage between the corporate governance of Italian water utilities (ownership, board size and board composition) and their ef fi ciency measured through data envelopment analysis (DEA). Using a general panel data regression model, we found that board size negatively affects the ef fi ciency of water utilities. Moreover, the presence of directors with political af fi liations or who are/were members of local or national go- vernment negatively affects ef fi ciency, and the presence of directors with a degree on the board has a slight negative effect on productivity. Conversely, other variables (ownership, gender diversity and average age of board members) were found not to affect the ef fi ciency of Italian water utilities. The existence of economies of scale was also confirmed .Este artĆculo analiza la relaciĆ³n entre el gobierno corporativo de los servicios del agua italianos (propiedad, tamaƱo y composiciĆ³n del consejo) y su e fi ciencia medida a travĆ©s del anĆ”lisis envolvente de datos (AED). Usando un modelo general de regresiĆ³n de datos de panel averiguamos que el tamaƱo del consejo afecta negativamente la e fi ciencia de los servicios del agua. AdemĆ”s, la presencia de directores con a fi liaciones polĆticas o que son o fueron miembros del gobierno local o nacional afecta negativamente a la e fi ciencia, y la presencia de directores con una carrera universitaria en el consejo tiene un efecto ligeramente negativo sobre la productividad. Inversamente, otras variables (propiedad, diversidad de gĆ©nero y edad media de los miembros del consejo) no afectan a la e fi ciencia de los servicios del agua italianos. La existencia de economĆas de escala tambiĆ©n fue con fi rmada
Physical parameters kinetics during the drying process of quarters and halves cut tomatoes
Received: January 27th, 2023 ; Accepted: May 8th, 2023 ; Published: May 19th, 2023 ; Correspondence: [email protected] drying is a time-consuming industrial process. Moreover, the prolonged use
of high temperatures decreases the quality of tomatoes and increases the environmental footprint
of the process. In most cases, drying is performed on halved tomatoes. Alternatively, the use of
quarter tomatoes could guarantee a drying times reduction without compromising the final
product quality. This work aimed at modelling changes in physical characteristics of half and
quarter tomatoes. The drying tests were conducted at 50 and 60 Ā°C. The kinetics of weight loss,
colour change, and volume reduction were determined. Colour change was monitored through
image analysis, while volume reduction using RGB-D reconstructions. Based on the results, an
increase in the drying temperature and the use of quartered tomatoes allow a significant reduction
in drying times. The loss of water kinetic allowed the determination of critical moisture. Between
initial and critical moisture, loss of water occurred at constant rate (zero-order kinetic), while
after that the rate decreased exponentially (first-order kinetic). The colour kinetics showed an
initial constant rate followed by a linear increase for brown pixels. The variation of red pixels did
not have a clear trend. Increasing the temperature there was no significant reduction in colour
quality while quarter tomatoes showed a greater loss of redness than halved tomatoes.
Furthermore, the temperature increase does not affect the volume reduction of the tomatoes.
Increasing the temperature and the use of quartered tomatoes are simple solutions to reduce
drying times. However, quartered tomatoes are less visually appreciable than halved tomatoes
Metagenomic analysis through the extended Burrows-Wheeler transform
Background: The development of Next Generation Sequencing (NGS) has had a major impact on the study of genetic sequences. Among problems that researchers in the field have to face, one of the most challenging is the taxonomic classification of metagenomic reads, i.e., identifying the microorganisms that are present in a sample collected directly from the environment. The analysis of environmental samples (metagenomes) are particularly important to figure out the microbial composition of different ecosystems and it is used in a wide variety of fields: for instance, metagenomic studies in agriculture can help understanding the interactions between plants and microbes, or in ecology, they can provide valuable insights into the functions of environmental communities. Results: In this paper, we describe a new lightweight alignment-free and assembly-free framework for metagenomic classification that compares each unknown sequence in the sample to a collection of known genomes. We take advantage of the combinatorial properties of an extension of the Burrows-Wheeler transform, and we sequentially scan the required data structures, so that we can analyze unknown sequences of large collections using little internal memory. The tool LiME (Lightweight Metagenomics via eBWT) is available at https://github.com/veronicaguerrini/LiME. Conclusions: In order to assess the reliability of our approach, we run several experiments on NGS data from two simulated metagenomes among those provided in benchmarking analysis and on a real metagenome from the Human Microbiome Project. The experiment results on the simulated data show that LiME is competitive with the widely used taxonomic classifiers. It achieves high levels of precision and specificity - e.g. 99.9% of the positive control reads are correctly assigned and the percentage of classified reads of the negative control is less than 0.01% - while keeping a high sensitivity. On the real metagenome, we show that LiME is able to deliver classification results comparable to that of MagicBlast. Overall, the experiments confirm the effectiveness of our method and its high accuracy even in negative control samples
Lossy Compressor preserving variant calling through Extended BWT
A standard format used for storing the output of high-throughput sequencing
experiments is the FASTQ format. It comprises three main components: (i)
headers, (ii) bases (nucleotide sequences), and (iii) quality scores. FASTQ
files are widely used for variant calling, where sequencing data are mapped
into a reference genome to discover variants that may be used for further
analysis. There are many specialized compressors that exploit redundancy in
FASTQ data with the focus only on either the bases or the quality scores
components. In this paper we consider the novel problem of lossy compressing,
in a reference-free way, FASTQ data by modifying both components at the same
time, while preserving the important information of the original FASTQ. We
introduce a general strategy, based on the Extended Burrows-Wheeler Transform
(EBWT) and positional clustering, and we present implementations in both
internal memory and external memory. Experimental results show that the lossy
compression performed by our tool is able to achieve good compression while
preserving information relating to variant calling more than the competitors.
Availability: the software is freely available at
https://github.com/veronicaguerrini/BFQzip.Comment: Proceedings of the 15th International Joint Conference on Biomedical
Engineering Systems and Technologie
Improved Face Tracking Thanks to Local Features Correspondence
In this paper, we propose a technique to enhance the quality of detected face tracks in videos. In particular, we present a tracking algorithm that can improve the temporal localization of the tracks, remedying to the unavoidable failures of the face detection algorithms. Local features are extracted and tracked to āfill the gapsā left by missed detections. The principal aim of this work is to provide robust and well localized tracks of faces to a system of Interactive Movietelling, but the concepts can be extended whenever there is the necessity to localize the presence of a determined face even in environments where the face detection is, for any reason, difficult. We test the effectiveness of the proposed algorithm in terms of faces localization both in space and time, first assessing the performance in an ad-hoc simulation scenario and then showing output examples of some real-world video sequences
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