Use of SVM Methods with Surface-Based Cortical and Volumetric Subcortical Measurements to Detect Alzheimer`s Disease

Here, we examine morphological changes in cortical thickness of patients with Alzheimer`s disease (AD) using image analysis algorithms for brain structure segmentation and study automatic classification of AD patients using cortical and volumetric data. Cortical thickness of AD patients (n = 14) was measured using MRI cortical surface-based analysis and compared with healthy subjects (n = 20). Data was analyzed using an automated algorithm for tissue segmentation and classification. A Support Vector Machine (SVM) was applied over the volumetric measurements of subcortical and cortical structures to separate AD patients from controls. The group analysis showed cortical thickness reduction in the superior temporal lobe, parahippocampal gyrus, and enthorhinal cortex in both hemispheres. We also found cortical thinning in the isthmus of cingulate gyrus and middle temporal gyrus at the right hemisphere, as well as a reduction of the cortical mantle in areas previously shown to be associated with AD. We also confirmed that automatic classification algorithms (SVM) could be helpful to distinguish AD patients from healthy controls. Moreover, the same areas implicated in the pathogenesis of AD were the main parameters driving the classification algorithm. While the patient sample used in this study was relatively small, we expect that using a database of regional volumes derived from MRI scans of a large number of subjects will increase the SVM power of AD patient identification.

Long-term cannabis use and mental healthy

The mental health consequences of the daily or near-dailyuseof cannabisoveryearsand decades remain uncertain, and are likely to remain so for some time given the difficul ties involved in investigating them. Never theless, there is sufficient evidence that its effects are neither as benign as proponents of its legalisation often argue, nor as malign as some partisans of continued prohibition claim (Hall et a!, 1994).

Models of alcohol use by young adults: An examination of various attitude-behavior theories

Objective: The aim of this study was to test the effectiveness of various attitude-behavior theories in explaining alcohol use among young adults. The theory of reasoned action (TRA), the theory of planned behavior and an extension of the TRA that incorporates past behavior were compared by the method of maximum-likelihood estimation, as implemented in LISREL for Windows 8.12. Method: Respondents consisted of 122 university students (82 female) who were questioned about their attitudes, subjective norms, perceived behavioral control, past behavior and intentions relating to drinking behavior. Students received course credit for their participation in the research. Results: Overall, the results suggest that the extension of the theory of reasoned action which incorporates past behavior provides the best fit to the data. For these young adults, their intentions to drink alcohol were predicted by their past behavior as well as their perceptions of what important others think they should do (subjective norm). Conclusions: The main conclusions drawn from the research concern the importance of focusing on normative influences and past behavior in explaining young adult alcohol use. Issues regarding the relative merit of various alternative models and the need for greater clarity in the measure of attitudes are also discussed.

Relationship between use of technology and employment rates for people with physical disabilities in Australia: Implications for education and training programmes

This study examined the impact of computer and assistive device use on the employment status and vocational modes of people with physical disabilities in Australia. A survey was distributed to people over 15 years in age with physical disabilities living in the Brisbane area. Responses were received from 82 people, including those with spinal cord injuries, cerebral palsy and muscular dystrophy. Of respondents 46 were employed, 22 were unemployed, and 12 were either students or undertaking voluntary work. Three-quarters of respondents used a computer in their occupations, while 15 used assistive devices. Using logistic regression analysis it was found that gender, education, level of computer skill and computer training were significant predictors of employment outcomes. Neither the age of respondent nor use of assistive software were significant predictors. From information obtained in this study guidelines for a training programme designed to maximize the employability of people with physical disabilities were developed.

Effect of specific leaf nitrogen on radiation use efficiency and growth of sunflower

Specific leaf nitrogen (SLN, g/m(2)) is known to affect radiation use efficiency (RUE, g/MJ) in different crops, However, this association and importance have not been well established over a range of different nitrogen regimes for held-grown sunflower (Helianthus annuus L.). An experiment was conducted to investigate different combinations and rates of applied nitrogen on SLN, RUE, and growth of sunflower, A fully irrigated crop was sown on an alluvial-prairie soil (Fluventic Haplustoll) and treated with five combinations of applied nitrogen, Greater nitrogen increased biomass, grain number, and yield, but did not affect harvest index energy-corrected for oil (0.4) or canopy extinction coefficient (0.88), Decreases in biomass accumulation under low nitrogen treatments were associated,vith reductions in leaf area index (LAI) and light interception, When SLN and RUE were examined together, both were less in the anthesis to physiological maturity period, but relatively stable between bud visible and anthesis, However, the effects of canopy SLN on RUE were confounded by high SLN in the top of the canopy and the crop maintaining SLN by reducing LAI, Measurements of leaf CO2 assimilation and theoretical analyses of RUE supported that RUE was related to SLN, The major effect of nitrogen on early growth of sunflower was mediated by leaf area and the distribution of SLN in the canopy rather than direct effects of canopy SLN on RUE alone. Greater responses of RUE to SLN are more evident later in growth, and may be related to the demand of nitrogen by the grain.

Effect of radiation environment on radiation use efficiency and growth of sunflower

The level of incident radiation and the proportion of radiation that is diffuse affects radiation use efficiency (RUE) in crops, However, the degree of this effect, and its importance to growth and yield of sunflower (Helianthus annuus L.) have not been established. A field experiment was conducted to investigate the effects of radiation environment on RUE, growth, and yield of sunflower. A fully irrigated crop was sown on an alluvial-prairie soil (Fluventic Haplustoll) and was exposed to three distinct radiation environments. In two treatments, the level of incident radiation was reduced by 14 and 20% by suspending tao different types of polyethylene plastic films well above the crop. In addition to the reductions in incident radiation, the proportion of radiation that was diffuse was increased by about 14% in these treatments. Lower incident radiation and increased proportion of diffuse radiation had no effect on total biomass, phenology, leaf area, and the canopy light extinction coefficient (k = 0.89). However, yield was reduced in shaded treatments due to smaller grain size and lower harvest index. Although crop RUE measured over the entire crop cycle (1.25 g/MJ) did not differ significantly among treatments, there was a trend where RUE compensated for less intercepted incident radiation. Theoretical derivations of the response of RUE to different levels of incident radiation supported this finding. Shaded sunflower crops have the ability to produce biomass similar to unshaded crops by increasing RUE, but have lower harvest indices.

Rapid computation of static fields produced by thick circular solenoids

A straightforward method is proposed for computing the magnetic field produced by a circular coil that contains a large number of turns wound onto a solenoid of rectangular cross section. The coil is thus approximated by a circular ring containing a continuous constant current density, which is very close to the real situation when sire of rectangular cross section is used. All that is required is to evaluate two functions, which are defined as integrals of periodic quantities; this is done accurately and efficiently using trapezoidal-rule quadrature. The solution can be obtained so rapidly that this procedure is ideally suited for use in stochastic optimization, An example is given, in which this approach is combined with a simulated annealing routine to optimize shielded profile coils for NMR.

The recent Australian debate about the prohibition on cannabis use

This paper outlines the ethical arguments used in the Australian debate about whether or not to relax the prohibition on cannabis use by adults. Over the past two decades a rising prevalence of cannabis use in the Australian population has led to proposals for the decriminalization of the personal use of cannabis. Three states and territories have removed criminal penalties for personal use while criminal penalties are rarefy imposed in the remaining states. Libertarian arguments for legalization of cannabis use have attracted a great deal of media interest but very little public and political support. Other arguments in favour of decriminalization have attracted more support. One has been the utilitarian argument that prohibition has failed to deter cannabis use and the social costs of its continuation outweigh any benefits that it produces. Another has been the argument from hypocrisy that cannabis is less harmful than alcohol and so, on the grounds of consistency, if alcohol is legally available then so should cannabis. To date public opinion has not favoured legalization, although support for the decriminalization of personal cannabis use has increased. In the long term, the outcome of the debate may depend more upon trends in cannabis use and social attitudes among young adults than upon the persuasiveness of the arguments for a relaxation of the prohibition of cannabis.

Cell cycle model to describe animal cell size variation and lag between cell number and biomass dynamics

The use of cell numbers rather than mass to quantify the size of the biotic phase in animal cell cultures causes several problems. First, the cell size varies with growth conditions, thus yields expressed in terms of cell numbers cannot be used in the normal mass balance sense. Second, experience from microbial systems shows that cell number dynamics lag behind biomass dynamics. This work demonstrates that this lag phenomenon also occurs in animal cell culture. Both the lag phenomenon and the variation in cell size are explained using a simple model of the cell cycle. The basis for the model is that onset of DNA synthesis requires accumulation of G1 cyclins to a prescribed level. This requirement is translated into a requirement for a cell to reach a critical size before commencement of DNA synthesis. A slower gl-owing cell will spend more time in G1 before reaching the critical mass. In contrast, the period between onset of DNA synthesis and mitosis, tau(B), is fixed. The two parameters in the model, the critical size and tau(B), were determined from eight steady-state measurements of mean cell size in a continuous hybridoma culture. Using these parameters, it was possible to predict with reasonable accuracy the transient behavior in a separate shift-up culture, i.e., a culture where cells were transferred from a lean environment to a rich environment. The implications for analyzing experimental data for animal cell culture are discussed. (C) 1997 John Wiley & Sons, Inc.

Use of multiple channel pH monitoring for evaluation of ultra-distal reflux in patients after fundoplication for treatment of Barrett`s esophagus

Dysplasia and esophageal adenocarcinoma may arise in patients with Barrett`s esophagus after fundoplication esophageal pH monitoring showing no acid in esophagus. This suggests the need to develop methodology to evaluate the occurrence of ultra-distal reflux (1 cm above the LES). The objective of the study was to compare acid exposition in three different levels: 5 cm above the upper border of the LES, 1 cm above the LES and in the intrasphincteric region. Eleven patients with Barrett`s esophagus after Nissen fundoplication with no clinical, endoscopic and radiologic evidence of reflux were selected. Four-channel pH monitoring took place: channel A, 5 cm above the upper border of the LES; channel B, 1 cm above the LES; channel C, intrasphincteric; channel D, intragastric. The results of channels A, B and C were compared. There was significant increase in number of reflux episodes and a higher fraction of time with pH <4.0 in channel B compared to channel A. There was significant decrease in fraction of time with pH <4.0 in channel B compared to channel C. Two cases of esophageal adenocarcinoma were diagnosed in the studied patients. The region 1 cm above the upper border of the LES is more exposed to acid than the region 5 cm above the upper border of the LES, although this exposure occurred in reduced levels. The region 1 cm above the upper border of the LES is less exposed to acid than the intrasphincteric region.

Genetic algorithms for continuous optimization problems - a concept of parameter-space size adjustment

The concept of parameter-space size adjustment is pn,posed in order to enable successful application of genetic algorithms to continuous optimization problems. Performance of genetic algorithms with six different combinations of selection and reproduction mechanisms, with and without parameter-space size adjustment, were severely tested on eleven multiminima test functions. An algorithm with the best performance was employed for the determination of the model parameters of the optical constants of Pt, Ni and Cr.

Reprocessing and reuse of single-use medical devices used during hemodynamic procedures in Brazil: A widespread and largely overlooked problem

Background. Several medical devices used during hemodynamic procedures, particularly angiographic diagnostic and therapeutic cardiac catheters, are manufactured for single use only. However, reprocessing and reuse of these devices has been reported, to determine the frequency of reuse and reprocessing of single-use medical devices used during hemodynamic procedures in Brazil and to evaluate how reprocessing is performed. Design. National survey, conducted from December 1999 to July 2001. Methods. Most of the institutions affiliated with the Brazilian Society of Hemodynamic and Interventional Cardiology were surveyed by use of a questionnaire sent in the mail. Results. The questionnaire response rate was 50% (119 of 240 institutions). Of the 119 institutions that responded, 116 (97%) reported reuse of single-use devices used during hemodynamic procedures, and only 26 (22%) reported use of a standardized reprocessing protocol. Cleaning, flushing, rinsing, drying, sterilizing and packaging methods varied greatly and were mostly inadequate. Criteria for discarding reused devices varied widely. Of the 119 institutions that responded, 80 (67%) reported having a surveillance system for adverse events associated with the reuse of medical devices, although most of these institutions did not routinely review the data, and only 38 (32%) described a training program for the personnel who reprocessed single-use devices. Conclusions. The reuse of single-use devices used during hemodynamic procedures was very frequent in hospitals in Brazil. Basic guidance on how to reuse and reprocess single-use medical devices is urgently needed, because, despite the lack of studies to support reusing and reprocessing single-use medical devices, such devices are necessary in limited-resource areas in which these practices are current.

Seven-year trend analysis of nosocomial candidemia and antifungal (fluconazole and caspofungin) use in Intensive Care Units at a Brazilian University Hospital

Candidemia is associated with high morbidity and mortality resulting in significant increases in the length of patients` hospitalization and in healthcare costs. Critically ill patients are at particular risk for candidemia because of their debilitated condition and frequent need for invasive procedures. The aim of this study was to characterize the incidence and epidemiology of candidemia over a seven-year period in intensive care units (ICUs) and the use of fluconazole and caspofungin in a large university-affiliated hospital. All cases of candidemia were identified by surveillance, using the Centers for Diseases Control and Prevention criteria. Demographic variables, use of antifungal (fluconazole and caspofungin) and patient outcomes were evaluated. The 2 test for linear trend was employed to evaluate the distribution of Candida spp. and the use of fluconazole and caspofungin by defined daily dose (DDD) per 1,000 patients-days during the study period. One hundred and eight episodes of candidemia were identified. The overall incidence of candidemia (P=0.20) and incidence of non-Candida albicans Candida infections (P=0.32) remained stable over the study period and ranged from 0.3-0.9 episodes per 1,000 catheter-days and 0.39-0.83 episodes per 1,000 patients-days. However, the use of fluconazole and caspofungin increased significantly (P0.001). While there were no reports of the use of fluconazole for prophylaxis in 1999, its use for this purpose increased from 3% in 2000 to 7.0% (P=0.07) in 2006. C. albicans was the most frequent specie isolated and burns and cancer were the most frequent underlying conditions. The overall mortality was 76%. There was no difference between C. albicans and non-C. albicans Candida infections when the crude and 14-day mortality rates were compared. Our data demonstrated that C. albicans is still the most frequent species causing candidemia in our intensive care units. Our rates of candidemia are lower than those reported from the region and similar to American and European hospitals. Although the incidence of blood stream infections (BSI) and candidemia remained stable, the use of fluconazole and caspofungin increased significantly over the years included in this study but had no impact on the incidence of infections caused by non-C. albicans Candida species.

Five-year evaluation of bloodstream yeast infections in a tertiary hospital: the predominance of non-C. albicans Candida species

This is a retrospective observational study of clinical and epidemiologic data from bloodstream yeast infections over 5 years (2004-2008) in a tertiary-care hospital. During this period, there were 52 such infections, at a rate of 2.4 per 1,000 hospital admissions. Non-C. albicans Candida species and other genera were responsible for 82% of infections, with C. tropicalis and C. parapsilosis being the most common. In 2008 no C. albicans infections occurred. Several uncommon fungal pathogens were observed, including Trichosporon asahii, Rhodotorula spp. and Candida zeylanoides. Of 16 isolates tested, 3 (19%) were resistant to fluconazole, including one C. zeylanoides (MIC 8 mu g/ml) and one C. tropicalis (MIC 16 mu g/ml) isolate, as well as intrinsically resistant C. krusei. All isolates tested were susceptible to itraconazole (n = 7) and amphotericin B (n = 8). Yeast infections were associated with severe underlying diseases, mainly hematological/solid cancers (71%), hospitalization in the ICU (41%), central venous catheters (80%), and use of antimicrobials (94%). The overall mortality rate was 50%. Our finding of a predominance of non-C. albicans Candida species infection with uncommon yeasts, and fluconazole resistance, suggests the need for continuous surveillance of fungemia and of antibiotic susceptibility trends, in order to adopt treatment strategies applicable to particular healthcare institutions.