A Fuzzy-Like Approach for Smoothing and Edge Detection in Color Images

Edge detection is one of the most important image processing steps towards image understanding. It is desired that edges be continuous and that the resultant regions or segments be completely isolated from their neighbors. Initially, images must first be smoothed to remove noise. In this paper, a novel fuzzy-like smoother algorithm is presented which removes camera noise and enhances edge contrast. The edge detection algorithm, which is applied on the smoothed image, is then presented. In this algorithm normalized hue in HSI space and color contrast in RGB space are combined using an aggregate operator. Pixels considered to be at least "nearly" locally maximum (defined within) are then found for all edge directions and the results are combined.

Prefrontal cortex lesions and MAO-A modulate aggression in penetrating traumatic brain injury

OBJECTIVE

This study investigates the interaction between brain lesion location and monoamine oxidase A (MAO-A) in the genesis of aggression in patients with penetrating traumatic brain injury (PTBI).

METHODS

We enrolled 155 patients with PTBI and 42 controls drawn from the Vietnam Head Injury Study registry. Patients with PTBI were divided according to lesion localization (prefrontal cortex [PFC] vs non-PFC) and were genotyped for the MAO-A polymorphism linked to low and high transcriptional activity. Aggression was assessed with the aggression/agitation subscale of the Neuropsychiatric Inventory (NPI-a).

RESULTS

Patients with the highest levels of aggression preferentially presented lesions in PFC territories. A significant interaction between MAO-A transcriptional activity and lesion localization on aggression was revealed. In the control group, carriers of the low-activity allele demonstrated higher aggression than high-activity allele carriers. In the PFC lesion group, no significant differences in aggression were observed between carriers of the 2 MAO-A alleles, whereas in the non-PFC lesion group higher aggression was observed in the high-activity allele than in the low-activity allele carriers. Higher NPI-a scores were linked to more severe childhood psychological traumatic experiences and posttraumatic stress disorder symptomatology in the control and non-PFC lesion groups but not in the PFC lesion group.

CONCLUSIONS

Lesion location and MAO-A genotype interact in mediating aggression in PTBI. Importantly, PFC integrity is necessary for modulation of aggressive behaviors by genetic susceptibilities and traumatic experiences. Potentially, lesion localization and MAO-A genotype data could be combined to develop risk-stratification algorithms and individualized treatments for aggression in PTBI.

Differences in health between Americans and Western Europeans: Effects on longevity and public finance

In 1975, 50-year-old Americans could expect to live slightly longer than most of their Western European counterparts. By 2005, American life expectancy had fallen behind that of most Western European countries. We find that this growing longevity gap is primarily due to real declines in the health of near-elderly Americans, relative to their Western European peers. We use a microsimulation approach to project what US longevity would look like, if US health trends approximated those in Western Europe. The model implies that differences in health can explain most of the growing gap in remaining life expectancy. In addition, we quantify the public finance consequences of this deterioration in health. The model predicts that gradually moving American cohorts to the health status enjoyed by Western Europeans could save up to $1.1 trillion in discounted total health expenditures from 2004 to 2050.

The increasing value of education to health

This paper assesses how the relationship between health and educational attainment has changed over the last three decades. We examine trends in disease prevalence and self-reported health using the US National Health Interview Survey for five chronic conditions-arthritis, diabetes, heart disease, hypertension, and lung diseases. The sample is limited to non-Hispanic Whites ages 40-64 to focus on the value of education and not changing representation of minority populations. We find that health benefits associated with additional schooling rose over time by more than ten percentage points as measured by self-reported health status. This can be attributed to both a growing disparity by education in the probability of having major chronic diseases during middle age, and better health outcomes for those with each disease. The value of education in achieving better health has increased over the last 25 years; both in protecting against onset of disease and promoting better health outcomes amongst those with a disease. Besides better access to health insurance, the more educated increasingly adapted better health behaviors, particularly not smoking and engaging in vigorous exercise, and reaped the benefits of improving medical technology. Rising health disparities by education are an important social concern which may require targeted interventions.

A CHRNA5 allele related to nicotine addiction and schizophrenia

Schizophrenia and nicotine addiction are both highly heritable phenotypes. Because individuals with schizophrenia have a higher rate of smoking than those in the general population, one could hypothesize that genes associated with smoking might be overrepresented in schizophrenia and thus help explain their increased smoking incidence. Although a number of genes have been proposed to explain the increased smoking risk in schizophrenia, none of them have been consistently linked to smoking and schizophrenia, and thus difficult to explain the increased smoking in schizophrenia. A functional smoking-related nicotinic acetylcholine receptor α5 subunit gene (CHRNA5) nonsynonymous single nucleotide polymorphism (SNP) rs16969968 (Asp398Asn) has recently been discovered and replicated. As such, we tested whether this variant contributes to smoking in schizophrenia in a sample of 313 schizophrenia patients and 525 controls. The Asp398Asn risk allele is significantly associated with smoking severity independently in schizophrenia patient smokers (P = 0.001) and control smokers (P = 0.029). Furthermore, the same risk allele is significantly associated with schizophrenia in both Caucasian (P = 0.022) and African-American (P = 0.006) nonsmoker schizophrenia patients compared with control nonsmokers. Intriguingly, this SNP was not significantly associated with smoking status (smokers vs. nonsmokers) in either schizophrenia patients or controls. Therefore, our study identifies a genetic variant that is simultaneously linked to smoking and schizophrenia in the same cohort, but whether this SNP contributes to the increased smoking prevalence in schizophrenia patients requires additional studies.

Influence of tissue metabolism and capillary oxygen supply on arteriolar oxygen transport: a computational model

We present a theoretical model for steady-state radial and longitudinal oxygen transport in arterioles containing flowing blood (plasma and red blood cells) and surrounded by living tissue. This model combines a detailed description of convective and diffusive oxygen transport inside the arteriole with a novel boundary condition at the arteriolar lumen surface, and the results provide new mass transfer coefficients for computing arteriolar O(2) losses based on far-field tissue O(2) tension and in the presence of spatially distributed capillaries. A numerical procedure is introduced for calculating O(2) diffusion from an arteriole to a continuous capillary-tissue matrix immediately adjacent to the arteriole. The tissue O(2) consumption rate is assumed to be constant and capillaries act as either O(2) sources or sinks depending on the local O(2) environment. Using the model, O(2) saturation (SO(2)) and tension (PO(2)) are determined for the intraluminal region of the arteriole, as well as for the extraluminal region in the neighbouring tissue. Our model gives results that are consistent with available experimental data and previous intraluminal transport models, including appreciable radial decreases in intraluminal PO(2) for all vessel diameters considered (12-100 μm) and slower longitudinal decreases in PO(2) for larger vessels than for smaller ones, and predicts substantially less diffusion of O(2) from arteriolar blood than do models with PO(2) specified at the edge of the lumen. The dependence of the new mass transfer coefficients on vessel diameter, SO(2) and far-field PO(2) is calculated allowing their application to a wide range of physiological situations. This novel arteriolar O(2) transport model will be a vital component of future integrated models of microvascular regulation of O(2) supply to capillary beds and the tissue regions they support.

Patient cost-sharing and healthcare spending growth

In this paper, we explore the role patient incentives play in slowing healthcare spending growth. Evidence suggests that while patients do indeed respond to financial incentives, cost-sharing does not uniformly improve value; rather, cost-sharing provisions must be deliberately structured and targeted to reduce care of low marginal value. Other mechanisms may be helpful in targeting particular populations or types of utilization. The spillover effects between privately insured and publicly insured populations as well as market imperfections suggest a potential role for public policy in promoting insurance design that slows spending growth while increasing the health that each dollar buys.

Breaking barriers in the genomics and pharmacogenetics of drug addiction

Drug addiction remains a substantial health issue with limited treatment options currently available. Despite considerable advances in the understanding of human genetic architecture, the genetic underpinning of complex disorders remains elusive. On the basis of our current understanding of neurobiology, numerous candidate genes have been implicated in the etiology and response to treatment for different addictions. Genome-wide association (GWA) studies have also identified novel targets. However, replication of these studies is often lacking, and this complicates interpretation. The situation is expected to improve as issues such as phenotypic characterization, the apparent "missing heritability," the identification of functional variants, and possible gene-environment (G × E) interactions are addressed. In addition, there is growing evidence that genetic information can be useful in refining the choice of addiction treatment. As genetic testing becomes more common in the practice of medicine, a variety of ethical and practical challenges, some of which are unique to drug addiction, will also need to be considered.

Bending the curve through health reform implementation

In September 2009, we released a set of concrete, feasible steps that could achieve the goal of significantly slowing spending growth while improving the quality of care. We stand by these recommendations, but they need to be updated in light of the new Patient Protection and Affordable Care Act (ACA). Reducing healthcare spending growth remains an urgent and unresolved issue, especially as the ACA expands insurance coverage to 32 million more Americans. Some of our reform recommendations were addressed completely or partially in ACA, and others were not. While more should be done legislatively, the current reform legislation includes important opportunities that will require decisive steps in regulation and execution to fulfill their potential for curbing spending growth. Executing these steps will not be automatic or easy. Yet doing so can achieve a healthcare system based on evidence, meaningful choice, balance between regulation and market forces, and collaboration that will benefit patients and the economy (see Appendix A for a description of these key themes). We focus on three concrete objectives to be reached within the next five years to achieve savings while improving quality across the health system: 1. Speed payment reforms away from traditional volume-based payment systems so that most health payments in this country align better with quality and efficiency. 2. Implement health insurance exchanges and other insurance reforms in ways that assure most Americans are rewarded with substantial savings when they choose plans that offer higher quality care at lower premiums. 3. Reform coverage so that most Americans can save money and obtain other meaningful benefits when they make decisions that improve their health and reduce costs. We believe these are feasible objectives with much progress possible even without further legislation (see Appendix B for a listing of recommendations). However, additional legislation is still needed to support consumers – including Medicare beneficiaries – in making choices that reduce costs while improving health.

Correlates of posttraumatic epilepsy 35 years following combat brain injury

BACKGROUND

The Vietnam Head Injury Study (VHIS) is a prospective, longitudinal follow-up of 1,221 Vietnam War veterans with mostly penetrating head injuries (PHIs). The high prevalence (45%-53%) of posttraumatic epilepsy (PTE) in this unique cohort makes it valuable for study.

METHODS

A standardized multidisciplinary neurologic, cognitive, behavioral, and brain imaging evaluation was conducted on 199 VHIS veterans plus uninjured controls, some 30 to 35 years after injury, as part of phase 3 of this study.

RESULTS

The prevalence of seizures (87 patients, 43.7%) was similar to that found during phase 2 evaluations 20 years earlier, but 11 of 87 (12.6%) reported very late onset of PTE after phase 2 (more than 14 years after injury). Those patients were not different from patients with earlier-onset PTE in any of the measures studied. Within the phase 3 cohort, the most common seizure type last experienced was complex partial seizures (31.0%), with increasing frequency after injury. Of subjects with PTE, 88% were receiving anticonvulsants. Left parietal lobe lesions and retained ferric metal fragments were associated with PTE in a logistic regression model. Total brain volume loss predicted seizure frequency.

CONCLUSIONS

Patients with PHI carry a high risk of PTE decades after their injury, and so require long-term medical follow-up. Lesion location, lesion size, and lesion type were predictors of PTE.

Early life stress, MAOA, and gene-environment interactions predict behavioral disinhibition in children

Several, but not all, studies have shown that the monoamine oxidase A functional promoter polymorphism (MAOA-LPR) interacts with childhood adversity to predict adolescent and adult antisocial behavior. However, it is not known whether MAOA-LPR interacts with early life (pre-birth-3 years) stressors to influence behavior in prepubertal children. The Avon Longitudinal Study of Parents and Children, UK, is a community-representative cohort study of children followed from pre-birth onwards. The impact of family adversity from pre-birth to age 3 years and stressful life events from 6 months to 7 years on behavioral disinhibition was determined in 7500 girls and boys. Behavioral disinhibition measures were: mother-reported hyperactivity and conduct disturbances (Strengths and Difficulties Questionnaire) at ages 4 and 7 years. In both sexes, exposure to family adversity and stressful life events in the first 3 years of life predicted behavioral disinhibition at age 4, persisting until age 7. In girls, MAOA-LPR interacted with stressful life events experienced from 6 months to 3.5 years to influence hyperactivity at ages 4 and 7. In boys, the interaction of MAOA-LPR with stressful life events between 1.5 and 2.5 years predicted hyperactivity at age 7 years. The low activity MAOA-LPR variant was associated with increased hyperactivity in girls and boys exposed to high stress. In contrast, there was no MAOA-LPR interaction with family adversity. In a general population sample of prepubertal children, exposure to common stressors from pre-birth to 3 years predicted behavioral disinhibition, and MAOA-LPR- stressful life event interactions specifically predicted hyperactivity.

Mass Transfer in a Rigid Tube With Pulsatile Flow and Constant Wall Concentration

An approximate-analytical solution method is presented for the problem of mass transfer in a rigid tube with pulsatile flow. For the case of constant wall concentration, it is shown that the generalized integral transform (GIT) method can be used to obtain a solution in terms of a perturbation expansion, where the coefficients of each term are given by a system of coupled ordinary differential equations. Truncating the system at some large value of the parameter N, an approximate solution for the system is obtained for the first term in the perturbation expansion, and the GIT-based solution is verified by comparison to a numerical solution. The GIT approximate-analytical solution indicates that for small to moderate nondimensional frequencies for any distance from the inlet of the tube, there is a positive peak in the bulk concentration C(1b) due to pulsation, thereby, producing a higher mass transfer mixing efficiency in the tube. As we further increase the frequency, the positive peak is followed by a negative peak in the time-averaged bulk concentration and then the bulk concentration C(1b) oscillates and dampens to zero. Initially, for small frequencies the relative Sherwood number is negative indicating that the effect of pulsation tends to reduce mass transfer. There is a band of frequencies, where the relative Sherwood number is positive indicating that the effect of pulsation tends to increase mass transfer. The positive peak in bulk concentration corresponds to a matching of the phase of the pulsatile velocity and the concentration, respectively, where the unique maximum of both occur for certain time in the cycle. The oscillatory component of concentration is also determined radially in the tube where the concentration develops first near the wall of the tube, and the lobes of the concentration curves increase with increasing distance downstream until the concentration becomes fully developed. The GIT method proves to be a working approach to solve the first two perturbation terms in the governing equations involved.

MARKET EVIDENCE OF MISPERCEIVED MORTALITY RISK

We construct and implement a test of rational consumer behavior in a high-stakes financial market. In particular, we test whether consumers make systematic mistakes in perceiving their mortality risks. We implement this test using data from secondary life insurance markets where consumers with a life-threatening illness sell their life insurance policies to firms in return for an up-front payment. We compare predictions from two models: one with consumers who correctly perceive their mortality risk, and one with consumers who are misguided about their life expectancy, and find that our data are most consistent with the predictions made by the second model.