Yisrael Parmet

Disparity in Melanoma: A Trend Analysis of Melanoma Incidence and Stage at Diagnosis Among Whites, Hispanics, and Blacks in Florida

OBJECTIVE To examine and compare the temporal trends in melanoma incidence and stage at diagnosis among whites, Hispanics, and blacks in Florida from 1990 to 2004. DESIGN Cross-sectional and retrospective analysis. SETTING Florida Cancer Data System. PATIENTS Melanoma cases with known stage and race/ethnicity reported from 1990 to 2004. MAIN OUTCOME MEASURES Age-adjusted melanoma incidence and stage at diagnosis. RESULTS Of 41 072 cases of melanoma, 39 670 cases were reported for white non-Hispanics (WNHs), 1148 for white Hispanics (WHs), and 254 for blacks. Melanoma incidence rates increased by 3.0% per year among WNH men (P < .001), 3.6% among WNH women (P < .001), 3.4% among WH women (P = .01), and 0.9% among WH men (P = .52), while remaining relatively stable among black men and women. Both WHs and blacks had significantly more advanced melanoma at presentation: 18% of WH and 26% of black patients had either regional or distant-stage melanoma at diagnosis compared with 12% of WNH patients. The proportion of distant-stage melanoma diagnosed among WHs and blacks changed little from 1990 to 2004, compared with a steady decrease in the percentage of melanoma cases diagnosed at distant stage among WNHs (P < .001). Such differences in the time trends of the proportion of distant-stage melanoma remained after excluding in situ cases. CONCLUSIONS The rising melanoma incidence among WNHs and WHs emphasizes the need for primary prevention. The persistence of disparity in melanoma stage at diagnosis among WHs, blacks, and WNHs warrants closer examination of secondary prevention efforts in minority groups.

EEG Frequency Analysis in Demented and Nondemented Parkinsonian Patients

In an attempt to evaluate EEG changes associated with dementia in Parkinsons disease (PD), we performed frequency analysis in three groups of 10 subjects each; two with PD, and one normal control group. The PD patient groups were matched for age, sex, severity and duration of disease, but were discordant for the existence of dementia. Normals were age- and sex-matched healthy volunteers. The relative alpha amplitude was significantly decreased in the demented PD patients, unrelated to motor disability. There was a nonsignificant but consistent trend of increased amplitude in the delta and theta range in the demented PD patients as compared to nondemented PD subjects and normal controls, as well as increased amplitude in the theta and delta range with more severe motor disability in the nondemented PD patients.

Developing a sampling plan based on Cpk—unknown variance

Common acceptance sampling plans for variables do not take into account the process performance while determining the sample size needed. An attempt to overcome this gap was suggested by Negrin et al. (Quality Eng. 2009; 21: 306–318), where a sampling plan based on the Cpk index was developed. The plan is a multistage acceptance sampling plan based on Cpk for variables taken as a random sample from a lot of size N having (approximately) normal distribution with a known variance. In the current research, we relax the assumption of a known variance and develop a Cpk sampling plan based on unknown variance. We develop a sample size model and update the acceptance/rejection criteria of the previous sampling plan to the new, more realistic model with unknown variance. In addition we develop the operational characteristic curve (OCC). The sampling plan is compared with the commonly used plan MIL-STD-414 (Sampling Procedures and Tables for Inspection by Variables for Percent Defective. Department of Defense: Washington, DC, 1957) and it is found (via simulations) that the Cpk sampling plan has a smaller probability of accepting defective lots and the required sample size needed is found to be smaller for large lots. In addition, a comparison is made between the two OCCs and it is found that the OCC developed for the Cpk sampling plan shows a higher accuracy (in an order of magnitude) in classifying lots correctly. Copyright

Usage and perceived effectiveness of fatigue countermeasures for professional and nonprofessional drivers

BACKGROUND Drivers adopt various strategies in order to cope with fatigue and falling asleep at the wheel. These strategies include a wide range of activities that may invigorate the body and/or the mind. OBJECTIVES To compare usage patterns and to evaluate the perceived effectiveness of different coping behaviors adopted by professional and nonprofessional drivers in order to maintain alertness. METHOD The study was conducted using a large-scale survey, filled by 100 professional and 90 nonprofessional drivers. RESULTS Listening to the radio and opening the window were the most frequently used and also perceived as highly effective coping behaviors by both groups of drivers. Talking on a cellular phone or with a passenger were more frequently used by nonprofessional drivers whereas, planning rest stops ahead, stopping for a short nap and drinking coffee were more frequently used by professional drivers. These methods were also perceived as more effective by professional than by the nonprofessional drivers and their usage frequency highly correlated with their perceived effectiveness. CONCLUSIONS Nonprofessional drivers counteract fatigue only at the tactical/maneuvering level of the drive. Hence, they tend to adopt methods that help them pass the time and reduce their feeling of boredom but do not require advance preparations or adjustments in the driving. In contrast, professional drivers counteract fatigue also at the strategic/planning level of driving, and use a much larger repertoire of coping-behaviors. IMPLICATIONS Fatigue countermeasures should include all levels of the driving task hierarchy, and experience-based countermeasures used by professional drivers should be considered for experimental validation.

Laplace inversion of low-resolution NMR relaxometry data using sparse representation methods

Low-resolution nuclear magnetic resonance (LR-NMR) relaxometry is a powerful tool that can be harnessed for characterizing constituents in complex materials. Conversion of the relaxation signal into a continuous distribution of relaxation components is an ill-posed inverse Laplace transform problem. The most common numerical method implemented today for dealing with this kind of problem is based on L2-norm regularization. However, sparse representation methods via L1 regularization and convex optimization are a relatively new approach for effective analysis and processing of digital images and signals. In this article, a numerical optimization method for analyzing LR-NMR data by including non-negativity constraints and L1 regularization and by applying a convex optimization solver PDCO, a primal-dual interior method for convex objectives, that allows general linear constraints to be treated as linear operators is presented. The integrated approach includes validation of analyses by simulations, testing repeatability of experiments, and validation of the model and its statistical assumptions. The proposed method provides better resolved and more accurate solutions when compared with those suggested by existing tools.

Drivers’ perception of vulnerable road users: A hazard perception approach

The present study examined how experienced and young-inexperienced drivers (either trained in hazard perception or not) respond to and identify pedestrians when they appear in residential roads within populated neighborhoods and in urban roads located outside neighborhoods and usually less populated. As part of a hazard perception test, participants were connected to an eye tracking system and were asked to observe 58 traffic scene movies and press a response button each time they detected a hazardous situation. Analyzing all pedestrian-related events revealed that, regardless of driving experience or training, drivers detect pedestrians less often when they appear in urban areas and more often when they appear in residential areas. Moreover, experienced drivers processed information more efficiently than young-inexperienced drivers (both trained and untrained) when pedestrians were identified. Visual search patterns in urban and residential traffic environments are discussed.

Should losartan be administered following brain injury

Brain injury is a major health concern and associated with delayed neurological complications, including post-injury epilepsy, cognitive and emotional disabilities. Currently, there is no strategy to prevent post-injury delayed complications. We recently showed that dysfunction of the blood–brain barrier, often reported in brain injuries, can lead to epilepsy and neurodegeneration via activation of inflammatory TGF-β signaling in astrocytes. We further showed that the FDA approved angiotensin II type 1 receptor antagonist, losartan, blocks brain TGF-β signaling and prevents epilepsy in the albumin or blood–brain barrier breakdown models of epileptogenesis. Here we discuss the potential of losartan as an anti-epileptogenic and a neuroprotective drug, the rationale of its use following brain injury and the challenges of designing clinical trials. We highlight the urgent need to develop reliable biomarkers for epileptogenesis (and other complications) after brain injury as a pre-requisite to challenge neuroprotective therapies.

Host Based Intrusion Detection using Machine Learning

Detecting unknown malicious code (malcode) is a challenging task. Current common solutions, such as anti-virus tools, rely heavily on prior explicit knowledge of specific instances of malcode binary code signatures. During the time between its appearance and an update being sent to anti-virus tools, a new worm can infect many computers and cause significant damage. We present a new host-based intrusion detection approach, based on analyzing the behavior of the computer to detect the presence of unknown malicious code. The new approach consists on classification algorithms that learn from previous known malcode samples which enable the detection of an unknown malcode. We performed several experiments to evaluate our approach, focusing on computer worms being activated on several computer configurations while running several programs in order to simulate background activity. We collected 323 features in order to measure the computer behavior. Four classification algorithms were applied on several feature subsets. The average detection accuracy that we achieved was above 90% and for specific unknown worms even above 99%.

Compensatory Versus Noncompensatory Shoulder Movements Used for Reaching in Stroke

Background. The extent to which the upper-limb flexor synergy constrains or compensates for arm motor impairment during reaching is controversial. This synergy can be quantified with a minimal marker set describing movements of the arm-plane. Objectives. To determine whether and how (a) upper-limb flexor synergy in patients with chronic stroke contributes to reaching movements to different arm workspace locations and (b) reaching deficits can be characterized by arm-plane motion. Methods. Sixteen post-stroke and 8 healthy control subjects made unrestrained reaching movements to targets located in ipsilateral, central, and contralateral arm workspaces. Arm-plane, arm, and trunk motion, and their temporal and spatial linkages were analyzed. Results. Individuals with moderate/severe stroke used greater arm-plane movement and compensatory trunk movement compared to those with mild stroke and control subjects. Arm-plane and trunk movements were more temporally coupled in stroke compared with controls. Reaching accuracy was related to different segment and joint combinations for each target and group: arm-plane movement in controls and mild stroke subjects, and trunk and elbow movements in moderate/severe stroke subjects. Arm-plane movement increased with time since stroke and when combined with trunk rotation, discriminated between different subject groups for reaching the central and contralateral targets. Trunk movement and arm-plane angle during target reaches predicted the subject group. Conclusions. The upper-limb flexor synergy was used adaptively for reaching accuracy by patients with mild, but not moderate/severe stroke. The flexor synergy, as parameterized by the amount of arm-plane motion, can be used by clinicians to identify levels of motor recovery in patients with stroke.

Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

Background1H low field nuclear magnetic resonance (LF-NMR) relaxometry has been suggested as a tool to distinguish between different molecular ensembles in complex systems with differential segmental or whole molecular motion and/or different morphologies. In biodiesel applications the molecular structure versus liquid-phase packing morphologies of fatty acid methyl esters (FAMEs) influences physico-chemical characteristics of the fuel, including flow properties, operability during cold weather, blending, and more. Still, their liquid morphological structures have scarcely been studied. It was therefore the objective of this work to explore the potential of this technology for characterizing the molecular organization of FAMEs in the liquid phase. This was accomplished by using a combination of supporting advanced technologies.ResultsWe show that pure oleic acid (OA) and methyl oleate (MO) standards exhibited both similarities and differences in the 1H LF-NMR relaxation times (T2s) and peak areas, for a range of temperatures. Based on X-ray measurements, both molecules were found to possess a liquid crystal-like order, although a larger fluidity was found for MO, because as the temperature is increased, MO molecules separate both longitudinally and transversely from one another. In addition, both molecules exhibited a preferred direction of diffusion based on the apparent hydrodynamic radius. The close molecular packing arrangement and interactions were found to affect the translational and segmental motions of the molecules, as a result of dimerization of the head group in OA as opposed to weaker polar interactions in MO.ConclusionsA comprehensive model for the liquid crystal-like arrangement of FAMEs in the liquid phase is suggested. The differences in translational and segmental motions of the molecules were rationalized by the differences in the 1H LF-NMR T2 distributions of OA and MO, which was further supported by 13C high field (HF)-NMR spectra and 1H HF-NMR relaxation. The proposed assignment allows for material characterization based on parameters that contribute to properties in applications such as biodiesel fuels.