A comparison of dimension reduction methods with application to multi-spectral images of sand used in concrete

This paper presents a comparison of dimension reduction methods based on a novel machine vision application for estimating moisture content in sand used to make concrete. For the application in question it is very important to know the moisture content of the sand so as to ensure good-quality concrete. In order to achieve a continuous in-line approach for the concrete mixing, digital image analysis is used. Multi-spectral images, consisting of nine spectral bands in the visible and near infrared (NIR) range, were acquired. Each image consists of approximately 9 million pixels. Five different sand types were examined with 20–60 images for each type. To reduce the amount of data, features were extracted from the multi-spectral images; the features were summary statistics on single bands and pairs of bands as well as morphological summaries. The number of features (2,016) is high in relation to the number of observations and, therefore, dimension reductive methods are needed. Furthermore, speed, which is an important consideration, is aided by the use of a small number of variables. On top of that, fewer dimensions tend to give more robust results. Two traditional statistical methods for dimension reduction (forward selection and principal components) combined with ordinary least squares and one sophisticated chemometrics algorithm (genetic algorithm-partial least squares) are compared to the recently proposed least angle regression-elastic net (LARS-EN) model selection method.     

Development and performance comparison of two different approaches for stabilizing a harmonic mode-locked fiber laser at 40 GHz

What we believe to be a new and simple approach was developed for stabilizing a harmonic mode-locked fiber laser at 40 GHz. It uses a computer to tune the modulation frequency in a 100 kHz band near 40 GHz to follow variations in the length of the optical cavity. A second approach was also developed to compare with the new approach and to draw conclusions on its performance. Results for the pulse characteristics, side-mode suppression ratio, and timing jitter show that both approaches provide an efficient way of stabilizing a harmonic FM mode-locked fiber laser.     

Changes in concentrations of perfluorinated compounds, polybrominated diphenyl ethers, and polychlorinated biphenyls in Norwegian breast-milk during twelve months of lactation

At present, scientific knowledge on depuration rates of persistent organic pollutants (POPs) is limited and the previous assumptions of considerable reduction of body burdens through breast-feeding have recently been challenged. We therefore studied elimination rates of important POPs in nine Norwegian primiparous mothers and one mother breast-feeding her second child by collecting breast-milk samples (n = 70) monthly from about two weeks to up to twelve months after birth. Perfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and polychlorinated biphenyls (PCBs) were determined in the breast-milk samples. Linear mixed effect models were established for selected compounds, and significant decreases in the range of 1.2-4.7% in breast-milk concentrations per month were observed for a wide range of PCBs and PBDEs. For the first time, depuration rates for perfluorooctylsulfonate (PFOS) and perfluorooctanoic acid (PFOA) are presented, being 3.8 and 7.8% per month, respectively (p < 0.05). The relative amount of the branched PFOS isomers in the breast-milk samples was 18% on average (range 6-36%, RSD 30%). There were no significant differences in isomer pattern between the mothers, or changes during the lactation period. After a year of nursing the breast-milk concentrations of PFCs, PBDEs, and PCBs were reduced by 15-94%.     

非定常螺距的螺旋线在自动流水线中的应用

建立了绕椭圆柱面以等角速度旋转,又以变速度上升的非定常螺距的螺旋线方程。给出了螺距作为加速度函数的数学表达式、螺旋线上任意点的曲率、挠率及弧长的计算公式,讨论了其相关特性。通过实例,研究了非定常螺距的螺旋线方程在自动流水线中的应用。     

Genetic Dominant Variants in STUB1, Segregating in Families with SCA48, Display In Vitro Functional Impairments Indistinctive from Recessive Variants Associated with SCAR16

Variants in STUB1 cause both autosomal recessive (SCAR16) and dominant (SCA48) spinocerebellar ataxia. Reports from 18 STUB1 variants causing SCA48 show that the clinical picture includes later-onset ataxia with a cerebellar cognitive affective syndrome and varying clinical overlap with SCAR16. However, little is known about the molecular properties of dominant STUB1 variants. Here, we describe three SCA48 families with novel, dominantly inherited STUB1 variants (p.Arg51_Ile53delinsProAla, p.Lys143_Trp147del, and p.Gly249Val). All the patients developed symptoms from 30 years of age or later, all had cerebellar atrophy, and 4 had cognitive/psychiatric phenotypes. Investigation of the structural and functional consequences of the recombinant C-terminus of HSC70-interacting protein (CHIP) variants was performed in vitro using ubiquitin ligase activity assay, circular dichroism assay and native polyacrylamide gel electrophoresis. These studies revealed that dominantly and recessively inherited STUB1 variants showed similar biochemical defects, including impaired ubiquitin ligase activity and altered oligomerization properties of the CHIP. Our findings expand the molecular understanding of SCA48 but also mean that assumptions concerning unaffected carriers of recessive STUB1 variants in SCAR16 families must be re-evaluated. More investigations are needed to verify the disease status of SCAR16 heterozygotes and elucidate the molecular relationship between SCA48 and SCAR16 diseases.     

Automatic determination of synergies by radial basis function artificial neural networks for the control of a neural prosthesis.

This paper describes an automatic method for synthesizing the control for a neural prosthesis (NP) that could augment elbow flexion/extension and forearm pronation/supination in persons with hemiplegia. The basis for the control was a synergistic model of reaching and grasping that uses temporal and spatial synergies between the arm and body segments. The synergies were determined from the movement data measured in nondisabled persons during the performance of functional tasks. The work space was divided into six zones: distance (two attributes) and laterality (three attributes). Radial basis function artificial neural networks (RBF ANN) were used to determine synergies. Sets of RBF ANN characterized with good generalization were selected as control laws for elbow flexion/extension and forearm pronation/supination. The validation was performed for three categories: inter-subject, distance, and laterality generalization. For all of the defined spatial synergies, the correlation was high for inter-subject and distance, yet low for the laterality scenario. This suggests the necessity for implementing different maps for different directions, but the same maps for different distances. The natural movements of the upper arm then drive the lower arm (elbow flexion/extension and forearm pronation/supination) in a way that is very well suited for the administration of functional electrical therapy (FET) in persons with hemiplegia soon after the onset of impairment.     

Linewidth reduction by 6 orders of magnitude of a broad-area 729-nm diode laser

Diode lasers with a power output superior to 100 mW are in widespread use in medical as well as research applications. However, for such diodes lasing oscillation generally occurs simultaneously in several longitudinal and transverse modes that are unsuitable for high-resolution spectroscopy. We spectrally narrow a 100-mW broad-area diode laser by first using an extended cavity and then an electrical feedback produced by a Pound-Drever-Hall stabilization on a low-finesse reference cavity. Reduction of the linewidth by more than 6 orders of magnitude is achieved (the output linewidth is narrowed from 1 THz to less than 500 kHz), making possible its use for high-resolution spectroscopy. The power and the spectral qualities of this diode laser allow us to induce quantum jumps toward the D5/2 metastable level of single Ca+ ions.     

The predictive role of body image and anti-fat attitudes on attentional bias toward body area in haptic virtual reality environment

Virtual Reality - Evidence suggests that dissatisfaction with body image in women can be enhanced by exposure to media’s idealized images. The theory of social comparison and the avoidance...