Automatic 4-D Registration in Dynamic MR Renography Based on Over-complete Dyadic Wavelet and Fourier Transforms

Dynamic contrast-enhanced 4-D MR renography has the potential for broad clinical applications, but suffers from respiratory motion that limits analysis and interpretation. Since each examination yields at least over 10-20 serial 3-D images of the abdomen, manual registration is prohibitively labor-intensive. Besides in-plane motion and translation, out-of-plane motion and rotation are observed in the image series. In this paper, a novel robust and automated technique for removing out-of-plane translation and rotation with sub-voxel accuracy in 4-D dynamic MR images is presented. The method was evaluated on simulated motion data derived directly from a clinical patient's data. The method was also tested on 24 clinical patient kidney data sets. Registration results were compared with a mutual information method, in which differences between manually co-registered time-intensity curves and tested time-intensity curves were compared. Evaluation results showed that our method agreed well with these ground truth data

On spin-1 massive particles coupled to a Chern-Simons field

We study spin one particles interacting through a Chern-Simons field. In the Born approximation, we calculate the two body scattering amplitude considering three possible ways to introduce the interaction: (a) a Proca like model minimally coupled to a Chern-Simons field, (b) the model obtained from (a) by replacing the Proca's mass by a Chern-Simons term and (c) a complex Maxwell-Chern-Simons model minimally coupled to a Chern-Simons field. In the low energy regime the results show similarities with the Aharonov-Bohm scattering for spin 1/2 particles. We discuss the one loop renormalization program for the Proca's model. In spite of the bad ultraviolet behavior of the matter field propagator, we show that, up to one loop the model is power counting renormalizable thanks to the Ward identities satisfied by the interaction vertices.Comment: 14 pages, 5 figures, revte

An integrated approach to supply chain risk analysis

Despite the increasing attention that supply chain risk management is receiving by both researchers and practitioners, companies still lack a risk culture. Moreover, risk management approaches are either too general or require pieces of information not regularly recorded by organisations. This work develops a risk identification and analysis methodology that integrates widely adopted supply chain and risk management tools. In particular, process analysis is performed by means of the standard framework provided by the Supply Chain Operations Reference Model, the risk identification and analysis tasks are accomplished by applying the Risk Breakdown Structure and the Risk Breakdown Matrix, and the effects of risk occurrence on activities are assessed by indicators that are already measured by companies in order to monitor their performances. In such a way, the framework contributes to increase companies' awareness and communication about risk, which are essential components of the management of modern supply chains. A base case has been developed by applying the proposed approach to a hypothetical manufacturing supply chain. An in-depth validation will be carried out to improve the methodology and further demonstrate its benefits and limitations. Future research will extend the framework to include the understanding of the multiple effects of risky events on different processe

Prevalence of depressive symptoms and its associated factors in older adults: a cross-sectional study in Kathmandu, Nepal

OBJECTIVE: Globally, depression is one of the most prevalent and burdensome conditions in older adults. However, there are few population-based studies of depression in older adults in developing countries. In this paper, we examine the prevalence of depressive symptoms and explore possible contributory risk factors in older adults living in Nepal. METHODS: A cross-sectional study was conducted in two semi-urban communities in Kathmandu, Nepal. Depression was assessed using the 15-item Geriatric Depression Scale in 303 participants, aged 60 years and over. Multivariate logistic regression was then used to assess associations between potential risk factors and depression. RESULTS: More than half of the participants (n = 175, 60.6%) had significant depressive symptomatology, with 27.7% having scores suggesting mild depression. Illiteracy (aOR = 2.01, 95% CI: 1.08-3.75), physical immobility (aOR = 5.62, 95% CI: 1.76-17.99), the presence of physical health problems (aOR = 1.97, 95% CI: 1.03-3.77), not having any time spent with family members (aOR = 3.55, 95% CI: 1.29-9.76) and not being considered in family decision-making (aOR = 4.02, 95% CI: 2.01-8.04) were significantly associated with depression in older adults. CONCLUSION: The prevalence of depression was significant in older adults. There are clear associations of depression with demographic, social support and physical well-being factors in this population. Strategies that increase awareness in the community along with the health and social care interventions are needed to address the likely drivers of depression in older adults

Superoscillations and tunneling times

It is proposed that superoscillations play an important role in the interferences which give rise to superluminal effects. To exemplify that, we consider a toy model which allows for a wave packet to travel, in zero time and negligible distortion a distance arbitrarily larger than the width of the wave packet. The peak is shown to result from a superoscillatory superposition at the tail. Similar reasoning applies to the dwell time.Comment: 12 page

Associations of gestational glycemia and prepregnancy adiposity with offspring growth and adiposity in an Asian population

Background: maternal obesity and hyperglycemia increase risk of obesity and diabetes in offspring later in life.Objective: we examined the relation between gestational glycemia and prepregnancy body mass index (ppBMI) with offspring growth in an Asian mother-offspring cohort.Design: pregnant mothers undertook a 75-g 2-h oral-glucose-tolerance test at 26–28 wk of gestation. In 937 singleton offspring, ?9 serial measurements of weight and length were obtained from birth until 36 mo of age.Results: gestational fasting plasma glucose (FPG) was positively associated with birth weight (B: 0.17; 95% CI: 0.10, 0.24; P < 0.001) and birth BMI (B: 0.15; 95% CI: 0.06, 0.40; P = 0.001) but not at ?3 mo of age. In contrast, maternal ppBMI was positively associated with birth variables and conditional growth in weight and BMI in the first 36 mo of life. However, gestational FPG and prepregnancy obesity status interacted significantly for the association with offspring growth and overweight status in the first 36 mo of life (P-interaction < 0.01). In nonobese mothers, each unit increase in gestational FPG was associated with increased offspring weight (B: 0.08; 95% CI: 0.008, 0.16; P = 0.03) and BMI (B: 0.08; 95% CI: 0.003, 0.15; P = 0.04) as well as increased risk of overweight in the first 36 mo of life (OR: 1.36; 95% CI: 1.10, 1.68). However, in obese mothers, each unit increase in gestational FPG was associated with decreased offspring weight (B: ?0.01; 95% CI: ?0.02, ?0.003) and BMI (B: ?0.008; 95% CI: ?0.01, ?0.002) velocity (P < 0.01 for both) and decreased risk of overweight (OR: 0.59; 95% CI: 0.41, 0.86) in the first 36 mo of life.Conclusions: prepregnancy adiposity was associated with offspring growth in early childhood. Although pooled analyses showed no demonstrable difference by 3 mo of age, there were contrasting and opposite associations of gestational glycemia with weight and BMI in the first 36 mo of life in offspring of nonobese and obese mothers separately. This study was registered at clinicaltrials.gov as NCT0117487

Near-Limb Zeeman and Hanle Diagnostics

"Weak" magnetic-field diagnostics in faint objects near the bright solar disk are discussed in terms of the level of non-object signatures, in particular, of the stray light in telescopes. Calculated dependencies of the stray light caused by diffraction at the 0.5-, 1.6-, and 4-meter entrance aperture are presented. The requirements for micro-roughness of refractive and reflective primary optics are compared. Several methods for reducing the stray light (the Lyot coronagraphic technique, multiple stages of apodizing in the focal and exit pupil planes, apodizing in the entrance aperture plane with a special mask), and reducing the random and systematic errors are noted. An acceptable level of stray light in telescopes is estimated for the V-profile recording with a signal-to-noise ratio greater than three. Prospects for the limb chromosphere magnetic measurements are indicated.Comment: 11 pages, 3 figure

Classical paradoxes of locality and their possible quantum resolutions in deformed special relativity

In deformed or doubly special relativity (DSR) the action of the lorentz group on momentum eigenstates is deformed to preserve a maximal momenta or minimal length, supposed equal to the Planck length. The classical and quantum dynamics of a particle propagating in kappa-Minkowski spacetime is discussed in order to examine an apparent paradox of locality which arises in the classical dynamics. This is due to the fact that the Lorentz transformations of spacetime positions of particles depend on their energies, so whether or not a local event, defined by the coincidence of two or more particles, takes place appears to depend on the frame of reference of the observer. Here it is proposed that the paradox arises only in the classical picture, and may be resolved when the quantum dynamics is taken into account. If so, the apparent paradoxes arise because it is inconsistent to study physics in which Planck's constant is zero but the Planck length is non-vanishing. This may be relevant for phenomenology such as observations by FERMI, because at leading order there is both a direct and a stochastic dependence of arrival time on energy, due to an additional spreading of wavepackets.Comment: LaTeX, 28 pages, no figures, substantially revise

Generalized Phase Synchronization in unidirectionally coupled chaotic oscillators

We investigate phase synchronization between two identical or detuned response oscillators coupled to a slightly different drive oscillator. Our result is that phase synchronization can occur between response oscillators when they are driven by correlated (but not identical) inputs from the drive oscillator. We call this phenomenon Generalized Phase Synchronization (GPS) and clarify its characteristics using Lyapunov exponents and phase difference plots.Comment: 4 pages, 5 figure

Neural mechanisms underlying probalistic category learning in normal aging.

Probabilistic category learning engages neural circuitry that includes the prefrontal cortex and caudate nucleus, two regions that show prominent changes with normal aging. However, the specific contributions of these brain regions are uncertain, and the effects of normal aging have not been examined previously in probabilistic category learning. In the present study, using a blood oxygenation level-dependent functional magnetic resonance imaging block design, 18 healthy young adults (mean age, 25.5 ± 2.6 years) and 15 older adults (mean age, 67.1 ± 5.3 years) were assessed on the probabilistic category learning "weather prediction" test. Whole-brain functional images acquired using a 1.5T scanner (General Electric, Milwaukee, WI) with gradient echo, echo planar imaging (3/1 mm; repetition time, 3000 ms; echo time, 50 ms) were analyzed using second-level random-effects procedures [SPM99 (Statistical Parametric Mapping)]. Young and older adults displayed equivalent probabilistic category learning curves, used similar strategies, and activated analogous neural networks, including the prefrontal and parietal cortices and the caudate nucleus. However, the extent of caudate and prefrontal activation was less and parietal activation was greater in older participants. The percentage correct and reaction time were mainly positively correlated with caudate and prefrontal activation in young individuals but positively correlated with prefrontal and parietal cortices in older individuals. Differential activation within a circumscribed neural network in the context of equivalent learning suggests that some brain regions, such as the parietal cortices, may provide a compensatory mechanism for healthy older adults in the context of deficient prefrontal cortex and caudate nuclei responses. Copyright © 2005 Society for Neuroscience