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When are the most informative components for inference also the principal components?  [PDF]
Raj Rao Nadakuditi
Computer Science , 2013,
Abstract: Which components of the singular value decomposition of a signal-plus-noise data matrix are most informative for the inferential task of detecting or estimating an embedded low-rank signal matrix? Principal component analysis ascribes greater importance to the components that capture the greatest variation, i.e., the singular vectors associated with the largest singular values. This choice is often justified by invoking the Eckart-Young theorem even though that work addresses the problem of how to best represent a signal-plus-noise matrix using a low-rank approximation and not how to best_infer_ the underlying low-rank signal component. Here we take a first-principles approach in which we start with a signal-plus-noise data matrix and show how the spectrum of the noise-only component governs whether the principal or the middle components of the singular value decomposition of the data matrix will be the informative components for inference. Simply put, if the noise spectrum is supported on a connected interval, in a sense we make precise, then the use of the principal components is justified. When the noise spectrum is supported on multiple intervals, then the middle components might be more informative than the principal components. The end result is a proper justification of the use of principal components in the setting where the noise matrix is i.i.d. Gaussian and the identification of scenarios, generically involving heterogeneous noise models such as mixtures of Gaussians, where the middle components might be more informative than the principal components so that they may be exploited to extract additional processing gain. Our results show how the blind use of principal components can lead to suboptimal or even faulty inference because of phase transitions that separate a regime where the principal components are informative from a regime where they are uninformative.
A retrospective cohort study on lifestyle habits of cardiovascular patients: how informative are medical records?
Annemarie J Fouwels, Sebastiaan JH Bredie, Hub Wollersheim, Gerard M Schippers
BMC Health Services Research , 2009, DOI: 10.1186/1472-6963-9-59
Abstract: For 209 patients information from medical records on lifestyle habits, physician feedback, and interventions in the past year was compared to data gathered in the last month by a self-report LSQ.Doctors register smoking habits most consistently (90.4%), followed by alcohol use (81.8%), physical activity (50.2%), and eating habits (27.3%). Compared to the LSQ, smoking, unhealthy alcohol use, physical activity, and unhealthy eating habits are underreported in medical records by 31, 83, 54 and 97%, respectively. Feedback, advice or referral was documented in 8% for smoking, 3% for alcohol use, 12% for physical activity, and 26% for eating habits.Lifestyle is insufficiently registered or recognized by doctors providing routine care in a cardiovascular outpatient setting. Of the unhealthy lifestyle habits that are registered, few are accompanied by notes on advice or intervention. A lifestyle questionnaire facilitates screening and interventions in target patients and should therefore be incorporated in the cardiovascular setting as a routine patient intake procedure.Cardiovascular and other non communicable diseases (NCD) account for most of the burden of ill health in Europe [1]. Most of these diseases are associated with common risk factors related to lifestyle habits like smoking, excessive alcohol use, unhealthy eating, and a insufficient physical activity that enhance the risk of developing cardiovascular diseases [2,3]. The WHO regional committee for Europe developed a comprehensive strategy for NCD that includes the active targeting of individuals at high risk and promotes disease prevention programmes[4]. In the Dutch adult general population about, 28% are smokers, 10% consume alcoholic beverages beyond health limits, only one third to one fifth eat fruit and vegetables as recommended, and 46% are overweight. [5]. Several studies in patients with elevated risk or manifest cardiovascular disease indicate favourable effects on cardiovascular risk profiles after a
The effectiveness of adding cognitive behavioural therapy aimed at changing lifestyle to managed diabetes care for patients with type 2 diabetes: design of a randomised controlled trial
Laura MC Welschen, Patricia van Oppen, Jacqueline M Dekker, Lex M Bouter, Wim AB Stalman, Giel Nijpels
BMC Public Health , 2007, DOI: 10.1186/1471-2458-7-74
Abstract: Patients with type 2 diabetes will be selected from general practices (n = 13), who are participating in a managed diabetes care system. Patients will be randomised into an intervention group receiving cognitive behaviour therapy (CBT) in addition to managed care, and a control group that will receive managed care only. The CBT consists of three to six individual sessions of 30 minutes to increase the patient's motivation, by using principles of MI, and ability to change their lifestyle, by using PST. The first session will start with a risk assessment of diabetes complications that will be used to focus the intervention.The primary outcome measure is the difference between intervention and control group in change in cardiovascular risk score. For this purpose blood pressure, HbA1c, total and HDL-cholesterol and smoking status will be assessed. Secondary outcome measures are quality of life, patient satisfaction, physical activity, eating behaviour, smoking status, depression and determinants of behaviour change. Differences between changes in the two groups will be analysed according to the intention-to-treat principle, with 95% confidence intervals. The power calculation is based on the risk for cardiovascular disease and we calculated that 97 patients should be included in every group.Cognitive behavioural therapy may improve self-management and thus strengthen managed diabetes care. This should result in changes in lifestyle and cardiovascular risk profile. In addition, we also expect an improvement of quality of life and patient satisfaction.Current Controlled Trials ISRCTN12666286Diabetes mellitus is a major health problem. It was estimated that in 2000 approximately 177 million people worldwide had diabetes, and this number is expected to double by the year 2030 [1]. Cardiovascular disease is the leading cause of death among patients with diabetes. Both cardiovascular disease and diabetes are associated with similar risk factors, namely unhealthy diet, smokin
Lifestyle changes in coronary heart disease—Effects of cardiac rehabilitation programs with focus on intensity, duration and content—A systematic review  [PDF]
Camilla Strid, Hans Lingfors, Bengt Fridlund, Jan M?rtensson
Open Journal of Nursing (OJN) , 2012, DOI: 10.4236/ojn.2012.24060
Abstract: Background: Although coronary heart disease (CHD) is the most common cause of death worldwide the literature shows a wide variation in the arrangement of cardiac rehabilitation and achieved lifestyle changes. Aim: The purpose of this study was to evaluate the effects of intensity (number of patient follow-ups), duration (length of intervention) and content in cardiac rehabilitation programs (CRP) regarding lifestyle changes in patients with CHD. Method: A systematic literature review of articles published in the databases PubMed and CINAHL between 1990 and 2007 was conducted. This resulted in 1120 hits of which 25 articles finally met the set criteria for inclusion. Results: The majority of significant positive results on lifestyle factors were shown among the studies describing high intensity and long duration. Included studies showed a wide variation in content, but four different interventions (informative content, educational content, practical content, behavioral and self care-oriented content) emerged. The group of studies which contained all four interventions focused on most lifestyle factors and achieved the most significant positive results. Conclusion: This systematic literature review shows that CRP should include high intensity, long duration and an intervention content covering information, knowledge, practical training, self care-activity and behavior changes in order to achieve effect on all four lifestyle factors of diet, physical activity and exercise, smoking and stress. Lifestyle changes can be reached in less lifestyle factors, with a longer duration and a variation of intensity of contacts but in combining with an informative and educational content with an additional content of a practical nature or self activity.
DiAlert: a lifestyle education programme aimed at people with a positive family history of type 2 diabetes and overweight, study protocol of a randomised controlled trial
Wieke H Heideman, Vera Nierkens, Karien Stronks, Barend JC Middelkoop, Jos WR Twisk, Arnoud P Verhoeff, Maartje de Wit, Frank J Snoek
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-751
Abstract: In this RCT, 268 (134 Dutch and 134 Turkish) overweight 1st degree relatives of patients with T2DM will be allocated to either the intervention or control group (leaflet). The intervention DiAlert aims to promote intrinsic motivation to change lifestyle, and sustain achieved behaviour changes during follow-up. Primary outcome is weight loss. Secondary outcomes include biological, behavioural and psychological indices, along with process indicators. Measurements will take place at baseline and after 3 and 9 months. Changes in outcomes are tested between intervention and control group at 3 months; effects over time are tested within and between both ethnic groups at 3 and 9 months.The DiAlert intervention is expected to be more effective than the control condition in achieving significant weight loss at 3 months, in both Dutch and Turkish Dutch participants.Netherlands National Trial Register (NTR): NTR2036The prevalence of people with type 2 diabetes (T2DM) in the general population is reaching epidemic proportions in many countries, with the total number of people with T2DM projected to rise to 366 million in 2030 worldwide [1]. It is therefore imperative that strategies to prevent the disease are implemented, this might include targeting high-risk populations to increase effectiveness. The increased prevalence is associated with lifestyle dependent risk factors, including being overweight, physical inactivity and unhealthy diet. In addition, the chance of developing T2DM is two to fourfold greater for people with a positive family history (FH) compared to those without, depending on the number of and the distance to the affected family members [2-4]. Since members of families share the same variations of genes, environment and behaviour patterns, family history information could possibly be used for screening and as a vehicle to motivate people at risk for T2DM to change behaviour [5,6]. However, targeting people with a positive family history of T2DM to promote li
Primary prevention of diabetes mellitus type 2 and cardiovascular diseases using a cognitive behavior program aimed at lifestyle changes in people at risk: Design of a randomized controlled trial
Jeroen Lakerveld, Sandra DM Bot, Marijke J Chinapaw, Maurits W van Tulder, Patricia van Oppen, Jacqueline M Dekker, Giel Nijpels
BMC Endocrine Disorders , 2008, DOI: 10.1186/1472-6823-8-6
Abstract: 12,000 inhabitants, 30-50 years of age living in several municipalities in the semi-rural region of West-Friesland will receive an invitation from their general practitioner (n = 13) to measure their own waist circumference with a tape measure. People with abdominal obesity (male waist ≥ 102 cm, female waist ≥ 88 cm) will be invited to participate in the second step of the screening which includes blood pressure, a blood sample and anthropometric measurements. T2DM and CVD risk scores will then be calculated according to the ARIC and the SCORE formulae, respectively. People with a score that indicates a high risk of developing T2DM and/or CVD will then be randomly assigned to the intervention group (n = 300) or the control group (n = 300).Participants in the intervention group will follow a CBP aimed at modifying their dietary behavior, physical activity, and smoking behavior. The counseling methods that will be used are motivational interviewing (MI) and problem solving treatment (PST), which focus in particular on intrinsic motivation for change and self-management of problems of the participants. The CBP will be provided by trained nurse practitioners in the participant's general practice, and will consists of a maximum of six individual sessions of 30 minutes, followed by 3-monthly booster sessions by phone. Participants in the control group will receive brochures containing health guidelines regarding physical activity and diet, and how to stop smoking. The primary outcome measures will be changes in T2DM and CVD risk scores. Secondary outcome measures will be changes in lifestyle behavior and cost-effectiveness and cost-utility ratios. All relevant direct and indirect costs will be measured, and there will be a follow-up of 24 months.Changing behaviors is difficult, requires time, considerable effort and motivation. Combining the two counseling methods MI and PST, followed by booster sessions may result in sustained behavioral change.Current Controlled Trials
Comparative genomics of the pathogenic ciliate Ichthyophthirius multifiliis, its free-living relatives and a host species provide insights into adoption of a parasitic lifestyle and prospects for disease control
Robert S Coyne, Linda Hannick, Dhanasekaran Shanmugam, Jessica B Hostetler, Daniel Brami, Vinita S Joardar, Justin Johnson, Diana Radune, Irtisha Singh, Jonathan H Badger, Ujjwal Kumar, Milton Saier, Yufeng Wang, Hong Cai, Jianying Gu, Michael W Mather, Akhil B Vaidya, David E Wilkes, Vidyalakshmi Rajagopalan, David J Asai, Chad G Pearson, Robert C Findly, Harry W Dickerson, Martin Wu, Cindy Martens, Yves Van de Peer, David S Roos, Donna M Cassidy-Hanley, Theodore G Clark
Genome Biology , 2011, DOI: 10.1186/gb-2011-12-10-r100
Abstract: We report the sequencing, assembly and annotation of the Ich macronuclear genome. Compared with its free-living relative T. thermophila, the Ich genome is reduced approximately two-fold in length and gene density and three-fold in gene content. We analyzed in detail several gene classes with diverse functions in behavior, cellular function and host immunogenicity, including protein kinases, membrane transporters, proteases, surface antigens and cytoskeletal components and regulators. We also mapped by orthology Ich's metabolic pathways in comparison with other ciliates and a potential host organism, the zebrafish Danio rerio.Knowledge of the complete protein-coding and metabolic potential of Ich opens avenues for rational testing of therapeutic drugs that target functions essential to this parasite but not to its fish hosts. Also, a catalog of surface protein-encoding genes will facilitate development of more effective vaccines. The potential to use T. thermophila as a surrogate model offers promise toward controlling 'white spot' disease and understanding the adaptation to a parasitic lifestyle.The ciliates are an ancient and diverse phylogenetic group related to the largely parasitic apicomplexans, but consisting mostly of free-living heterotrophs. Some ciliates, however, have adopted a parasitic lifestyle. By far the most important of these is Ichthyophthirius multifiliis (which we will refer to by its common name of Ich), an endoparasite that causes white spot disease in freshwater fish [1,2]. With an extremely broad host-range, Ich is responsible for large-scale die-offs in natural populations and poses a significant threat to the growing worldwide aquaculture industry. Ich has a simple life cycle with no intermediate hosts (Figure 1). The free-swimming theront form invades the epidermis of susceptible fish, feeding on host tissue and growing up to 0.5 mm in diameter. Host-associated trophonts become visible as individual white spots for which this disease is n
I.Д. Малицька
Information Technologies and Learning Tools , 2010,
Abstract: In the article the author analyses historic-pedagogical pre-conditions of the development of educational informative nets in the process of forming of modern informative society, examines influence of such international organizations as Council of Europe and European Unionon on their development. The analysis of concept of scientifically-pedagogical information is also conducted, its functions and methods of dissemination are determined. The place of the European informative educational nets in forming of universal informative educational space in Ukraine and abroad is analysed. В статт анал зуються сторико-педагог чн передумови створення нформац йних осв тн х мереж у процес формування сучасного нформац йного сусп льства, розгляда ться вплив на х розвиток таких м жнародних орган зац й як Рада вропи та вропейський Союз. В статт також проводиться анал з поняття науково-педагог чно нформац , визначаються функц та методи розповсюдження. Анал зу ться м сце вропейських нформац йних осв тн х мереж у формуванн диного нформац йного осв тнього простору Укра ни та заруб жж .
Informative Sensing  [PDF]
Hyun Sung Chang,Yair Weiss,William T. Freeman
Mathematics , 2009,
Abstract: Compressed sensing is a recent set of mathematical results showing that sparse signals can be exactly reconstructed from a small number of linear measurements. Interestingly, for ideal sparse signals with no measurement noise, random measurements allow perfect reconstruction while measurements based on principal component analysis (PCA) or independent component analysis (ICA) do not. At the same time, for other signal and noise distributions, PCA and ICA can significantly outperform random projections in terms of enabling reconstruction from a small number of measurements. In this paper we ask: given the distribution of signals we wish to measure, what are the optimal set of linear projections for compressed sensing? We consider the problem of finding a small number of linear projections that are maximally informative about the signal. Formally, we use the InfoMax criterion and seek to maximize the mutual information between the signal, x, and the (possibly noisy) projection y=Wx. We show that in general the optimal projections are not the principal components of the data nor random projections, but rather a seemingly novel set of projections that capture what is still uncertain about the signal, given the knowledge of distribution. We present analytic solutions for certain special cases including natural images. In particular, for natural images, the near-optimal projections are bandwise random, i.e., incoherent to the sparse bases at a particular frequency band but with more weights on the low-frequencies, which has a physical relation to the multi-resolution representation of images.
Making and Maintaining Lifestyle Changes after Participating in Group Based Type 2 Diabetes Self-Management Educations: A Qualitative Study  [PDF]
Marit B. Rise, Anneli Pellerud, Lisbeth ?. Rygg, Aslak Steinsbekk
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064009
Abstract: Background Disease management is crucial in type 2 diabetes. Diabetes self-management education aims to provide the knowledge necessary to make and maintain lifestyle changes. However, few studies have investigated the processes after such courses. The aim of this study was to investigate how participants make and maintain lifestyle changes after participating in group-based type 2 diabetes self-management education. Methods Data was collected through qualitative semi-structured interviews with 23 patients who attended educational group programs in Central Norway. The participants were asked how they had used the advice given and what they had changed after the course. Results Knowledge was essential for making lifestyle changes following education. Three factors affected whether lifestyle changes were implemented: obtaining new knowledge, taking responsibility, and receiving confirmation of an already healthy lifestyle. Four factors motivated individuals to maintain changes: support from others, experiencing an effect, fear of complications, and the formation of new habits. Conclusion Knowledge was used to make and maintain changes in diet, medication and physical activity. Knowledge also acted as confirmation of an already adequate lifestyle. Knowledge led to no changes if diabetes appeared “not that scary” or if changes appeared too time consuming. Those involved in diabetes education need to be aware of the challenges in convincing asymptomatic patients about the benefits of adherence to self-management behaviour.
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