Learning from Examples with Unspecified Attribute Values

We introduce the UAV learning model in which some of the attributes in the examples are unspecified. In our model, an example x is classified positive (resp., negative) if all possible assignments for the unspecified attributes result in a positive (resp., negative) classification. Otherwise the classificatoin given to x is ? (for unknown). Given an example x in which some attributes are unspecified, the oracle UAV-MQ responds with the classification of x. Given a hypothesis h, the oracle UAV-EQ returns an example x (that could have unspecified attributes) for which h(x) is incorrect. We show that any class learnable in the exact model using the MQ and EQ oracles is also learnable in the UAV model using the MQ and UAV-EQ oracles as long as the counterexamples provided by the UAV-EQ oracle have a logarithmic number of unspecified attributes. We also show that any class learnable in the exact model using the MQ and EQ oracles is also learnable in the UAV model using the UAV-MQ and UAV-EQ oracles as well as an oracle to evaluate a given boolean formula on an example with unspecified attributes. (For some hypothesis classes such as decision trees and unate formulas the evaluation can be done in polynomial time without an oracle.) We also study the learnability of a universal class of decision trees under the UAV model and of DNF formulas under a representation-dependent variation of the UAV model

Agnostic Learning of Geometric Patterns

Goldberg, Goldman, and Scott demonstrated how the problem of recognizing a landmark from a one-dimensional visual image can be mapped to that of learning a one-dimensional geometric pattern and gave a PAC algorithm to learn that class. In this paper, we present an efficient on-line agnostic learning algorithm for learning the class of constant-dimension geometric patterns. Our algorithm can tolerate both classification and attribute noise. By working in higher dimensional spaces we can represent more features from the visual image in the geometric pattern. Our mapping of the data to a geometric pattern, and hence our learning algorithm, is applicable to any data representable as a constant-dimensional array of values, e.g. sonar data, temporal difference information, or amplitudes of a waveform. To our knowledge, these classes of patterns are more complex than any class of geometric patterns previously studied. Also, our results are easily adapted to learn the union of fixed-dimensional boxes from multiple-instance examples. Finally, our algorithms are tolerant of concept shift

A novel skin cancer prevention strategy: Preservice teachers\u27 perceptions of a sun safety intervention and experiences in schools

Issue addressed: Teachers play a vital role in developing children\u27s sun protection routines however upskilling preservice teachers (PSTs) while at university has not yet been trialled as a targeted skin cancer prevention strategy. Hence, this study investigated PSTs perceptions and experiences of sun safety following a brief pilot intervention and placement in primary schools in Western Australia. Methods: This study used a triangulation mixed methods design. Participants (n = 161) completed a post intervention survey which was analysed quantitatively. A random sub-sample was invited to participate in focus groups (three groups, n = 21) and one-on-one interviews (n = 4). This data was transcribed and uploaded in NVIVO software for thematic analysis. Results: Participants felt the intervention increased their awareness of the dangers of overexposure to ultraviolet radiation (UVR) with many feeling more knowledgeable, skilled and confident to teach sun safety in school settings. Most reported clear sun safety messages in their placement schools. However, only 34.4 % reported they had been briefed on the school\u27s sun safety procedures. There was consensus among PSTs that sun protection in primary schools needs to be improved to maximise the protection of children from harmful UVR overexposure. Participants supported a need for consistent sun protection messaging across primary schools with greater emphasis on education rather than compliance management to sun protection. Conclusion: Enhancing existing teacher education programs to include more rigorous curriculum content and pedagogical approaches to sun protection education is a novel skin cancer prevention strategy and could feasibly support PSTs self-efficacy to effectively deliver sun safety curriculum in Australian schools

Targeted Teacher Education to Improve Primary Preservice Teachers’ Knowledge and Understanding of UV and Effective Sun Protection Measures for Children

Teachers are responsible for children at school during peak ultraviolet (UV) times of the day. It is paramount that teachers have knowledge and understanding of UV to effectively protect themselves and their students. The aim of this pilot study was to investigate the effect of a short intervention on preservice teachers’ sun protective behaviours, knowledge and perceived skill to teach sun safety. Participants (n =161; median age=20 years) attended a 45-minute preservice teacher sun safety intervention and completed pre- and post-test surveys. Post-intervention, most participants indicated they felt: i) more informed about the dangers of UV and risks of developing skin cancer (93.3%); ii) more knowledgeable about the importance of sun protection (92%); and iii) more skilled to teach sun safety (87.4%). Our findings indicate that the targeted preservice teacher sun safety education intervention improved understandings of UV, effective sun-protective practices, and their perceived skills to teach sun safety

A thin layer angiogenesis assay: a modified basement matrix assay for assessment of endothelial cell differentiation

BACKGROUND: Basement matrices such as Matrigel™ and Geltrex™ are used in a variety of cell culture assays of anchorage-dependent differentiation including endothelial cell tube formation assays. The volumes of matrix recommended for these assays (approximately 150 μl/cm(2)) are costly, limit working distances for microscopy, and require cell detachment for subsequent molecular analysis. Here we describe the development and validation of a thin-layer angiogenesis (TLA) assay for assessing the angiogenic potential of endothelial cells that overcomes these limitations. RESULTS: Geltrex™ basement matrix at 5 μl/cm(2) in 24-well (10 μl) or 96-well (2 μl) plates supports endothelial cell differentiation into tube-like structures in a comparable manner to the standard larger volumes of matrix. Since working distances are reduced, high-resolution single cell microscopy, including DIC and confocal imaging, can be used readily. Using MitoTracker dye we now demonstrate, for the first time, live mitochondrial dynamics and visualise the 3-dimensional network of mitochondria present in differentiated endothelial cells. Using a standard commercial total RNA extraction kit (Qiagen) we also show direct RNA extraction and RT-qPCR from differentiated endothelial cells without the need to initially detach cells from their supporting matrix. CONCLUSIONS: We present here a new thin-layer assay (TLA) for measuring the anchorage-dependent differentiation of endothelial cells into tube-like structures which retains all the characteristics of the traditional approach but with the added benefit of a greatly lowered cost and better compatibility with other techniques, including RT-qPCR and high-resolution microscopy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12860-014-0041-5) contains supplementary material, which is available to authorized users

Improvement of neuropathology and transcriptional deficits in CAG 140 knock-in mice supports a beneficial effect of dietary curcumin in Huntington's disease

<p>Abstract</p> <p>Backgound</p> <p>No disease modifying treatment currently exists for Huntington's disease (HD), a fatal neurodegenerative disorder characterized by the formation of amyloid-like aggregates of the mutated huntingtin protein. Curcumin is a naturally occurring polyphenolic compound with Congo red-like amyloid binding properties and the ability to cross the blood brain barrier. CAG140 mice, a knock-in (KI) mouse model of HD, display abnormal aggregates of mutant huntingtin and striatal transcriptional deficits, as well as early motor, cognitive and affective abnormalities, many months prior to exhibiting spontaneous gait deficits, decreased striatal volume, and neuronal loss. We have examined the ability of life-long dietary curcumin to improve the early pathological phenotype of CAG140 mice.</p> <p>Results</p> <p>KI mice fed a curcumin-containing diet since conception showed decreased huntingtin aggregates and increased striatal DARPP-32 and D1 receptor mRNAs, as well as an amelioration of rearing deficits. However, similar to other antioxidants, curcumin impaired rotarod behavior in both WT and KI mice and climbing in WT mice. These behavioral effects were also noted in WT C57Bl/6 J mice exposed to the same curcumin regime as adults. However, neither locomotor function, behavioral despair, muscle strength or food utilization were affected by curcumin in this latter study. The clinical significance of curcumin's impairment of motor performance in mice remains unclear because curcumin has an excellent blood chemistry and adverse event safety profile, even in the elderly and in patients with Alzheimer's disease.</p> <p>Conclusion</p> <p>Together with this clinical experience, the improvement in several transgene-dependent parameters by curcumin in our study supports a net beneficial effect of dietary curcumin in HD.</p

Pulmonary Biomarkers Based on Alterations in Protein Expression after Exposure to Arsenic

OBJECTIVE: Environmental exposure to arsenic results in multiple adverse effects in the lung. Our objective was to identify potential pulmonary protein biomarkers in the lung-lining fluid of mice chronically exposed to low-dose As and to validate these protein changes in human populations exposed to As. METHODS: Mice were administered 10 or 50 ppb As (sodium arsenite) in their drinking water for 4 weeks. Proteins in the lung-lining fluid were identified using two-dimensional gel electrophoresis (n = 3) or multidimensional protein identification technology (MUDPIT) (n = 2) coupled with mass spectrometry. Lung-induced sputum samples were collected from 57 individuals (tap water As ranged from ~ 5 to 20 ppb). Protein levels in sputum were determined by ELISA, and As species were analyzed in first morning void urine. RESULTS: Proteins in mouse lung-lining fluid whose expression was consistently altered by As included glutathione-S-transferase (GST)-omega-1, contraspin, apolipoprotein A-I and A-IV, enolase-1, peroxiredoxin-6, and receptor for advanced glycation end products (RAGE). Validation of the putative biomarkers was carried out by evaluating As-induced alterations in RAGE in humans. Regression analysis demonstrated a significant negative correlation (p = 0.016) between sputum levels of RAGE and total urinary inorganic As, similar to results seen in our animal model. CONCLUSION: Combinations of proteomic analyses of animal models followed by specific analysis of human samples provide an unbiased determination of important, previously unidentified putative biomarkers that may be related to human disease

Factors influencing quality of life following lower limb amputation for peripheral arterial occlusive disease: a systematic review of the literature

Background: The majority of lower limb amputations are undertaken in people with peripheral arterial occlusive disease,\ud and approximately 50% have diabetes. Quality of life is an important outcome in lower limb amputations; little is known\ud about what influences it, and therefore how to improve it.\ud Objectives: The aim of this systematic review was to identify the factors that influence quality of life after lower limb\ud amputation for peripheral arterial occlusive disease.\ud Methods: MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science and Cochrane databases were searched to identify\ud articles that quantitatively measured quality of life in those with a lower limb amputation for peripheral arterial occlusive\ud disease. Articles were quality assessed by two assessors, evidence tables summarised each article and a narrative\ud synthesis was performed.\ud Study design: Systematic review.\ud Results: Twelve articles were included. Study designs and outcome measures used varied. Quality assessment scores\ud ranged from 36% to 92%. The ability to walk successfully with a prosthesis had the greatest positive impact on quality\ud of life. A trans-femoral amputation was negatively associated with quality of life due to increased difficulty in walking\ud with a prosthesis. Other factors such as older age, being male, longer time since amputation, level of social support and\ud presence of diabetes also negatively affected quality of life.\ud Conclusion: Being able to walk with a prosthesis is of primary importance to improve quality of life for people with lower\ud limb amputation due to peripheral arterial occlusive disease. To further understand and improve the quality of life of this\ud population, there is a need for more prospective longitudinal studies, with a standardised outcome measure

Bacteremia among children admitted to a rural hospital in Kenya.

BACKGROUND: There are few epidemiologic data on invasive bacterial infections among children in sub-Saharan Africa. We studied every acute pediatric admission to a rural district hospital in Kenya to examine the prevalence, incidence, types, and outcome of community-acquired bacteremia. METHODS: Between August 1998 and July 2002, we cultured blood on admission from 19,339 inpatients and calculated the incidence of bacteremia on the basis of the population served by the hospital. RESULTS: Of a total of 1783 infants who were under 60 days old, 228 had bacteremia (12.8 percent), as did 866 of 14,787 children who were 60 or more days of age (5.9 percent). Among infants who were under 60 days old, Escherichia coli and group B streptococci predominated among a broad range of isolates (14 percent and 11 percent, respectively). Among infants who were 60 or more days of age, Streptococcus pneumoniae, nontyphoidal salmonella species, Haemophilus influenzae, and E. coli accounted for more than 70 percent of isolates. The minimal annual incidence of community-acquired bacteremia was estimated at 1457 cases per 100,000 children among infants under a year old, 1080 among children under 2 years, and 505 among children under 5 years. Of all in-hospital deaths, 26 percent were in children with community-acquired bacteremia. Of 308 deaths in children with bacteremia, 103 (33.4 percent) occurred on the day of admission and 217 (70.5 percent) within two days. CONCLUSIONS: Community-acquired bacteremia is a major cause of death among children at a rural sub-Saharan district hospital, a finding that highlights the need for prevention and for overcoming the political and financial barriers to widespread use of existing vaccines for bacterial diseases