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Minimum Threshold (minimum + threshold)
Selected AbstractsMedical association rule mining using genetic network programmingELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 2 2008Kaoru Shimada Abstract An efficient algorithm for building a classifier is proposed based on an important association rule mining using genetic network programming (GNP). The proposed method measures the significance of the association via the chi-squared test. Users can define the conditions of important association rules for building a classifier flexibly. The definition can include not only the minimum threshold chi-squared value, but also the number of attributes in the association rules. Therefore, all the extracted important rules can be used for classification directly. GNP is one of the evolutionary optimization techniques, which uses the directed graph structure as genes. Instead of generating a large number of candidate rules, our method can obtain a sufficient number of important association rules for classification. In addition, our method suits association rule mining from dense databases such as medical datasets, where many frequently occurring items are found in each tuple. In this paper, we describe an algorithm for classification using important association rules extracted by GNP with acquisition mechanisms and present some experimental results of medical datasets. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(2): 46,54, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10022 [source] Sensitive and simultaneous analysis of five transgenic maizes using multiplex polymerase chain reaction, capillary gel electrophoresis, and laser-induced fluorescenceELECTROPHORESIS, Issue 14 2004Virginia García-Cañas Abstract The benefits of using multiplex polymerase chain reaction (PCR) followed by capillary gel electrophoresis with laser-induced fluorescence (CGE-LIF) for the simultaneous detection of five transgenic maizes (Bt11, T25, MON810, GA21, and Bt176) are demonstrated. The method uses a hexaplex PCR protocol to amplify the five mentioned transgenic amplicons plus the zein gene used as reference, followed by a CGE-LIF method to analyze the six DNA fragments. CGE-LIF was demonstrated very useful and informative for optimizing multiplex PCR parameters such as time extension, PCR buffer concentration and primers concentration. The method developed is highly sensitive and allows the simultaneous detection in a single run of percentages of transgenic maize as low as 0.054% of Bt11, 0.057% of T25, 0.036% of MON810, 0.064% of GA21, and 0.018% of Bt176 in flour obtaining signals still far from the detection limit (namely, the signal/noise ratios for the corresponding DNA peaks were 41, 124, 98, 250, 252, and 473, respectively). These percentages are well below the minimum threshold marked by the European Regulation for transgenic food labeling (i.e., 0.5,0.9%). A study on the reproducibility of the multiplex PCR-CGE-LIF procedure was also performed. Thus, values of RSD lower than 0.67 and 6.80% were obtained for migration times and corrected peak areas, respectively, for the same sample and three different days (n = 12). On the other hand, the reproducibility of the whole procedure, including four different multiplex PCR amplifications, was determined to be better than 0.66 and 23.3% for migration times and corrected peak areas, respectively. Agarose gel electrophoresis (AGE) and CGE-LIF were compared in terms of resolution and sensitivity for detecting PCR products, demonstrating that CGE-LIF can solve false positives induced by artifacts from the multiplex PCR reaction that could not be addressed by AGE. Moreover, CGE-LIF provides better resolution and sensitivity. To our knowledge, these results demonstrate for the first time that multiplex PCR-CGE-LIF is a solid alternative to determine multiple genetically modified organisms in maize flours in a single run. [source] Identification of novel genes regulated by ,-melanocyte-stimulating hormone in murine bone marrow-derived dendritic cellsEXPERIMENTAL DERMATOLOGY, Issue 9 2004T. Brzoska Many strains of evidence indicate that ,-melanocyte-stimulating hormone (,-MSH) elicits its immunomodulatory activity via binding to melanocortin receptors (MC-Rs) expressed on monocytes and dendritic cells. In order to identify novel target genes regulated by ,-MSH in these cells, we prepared bone marrow-derived dendritic cell precursors from BALB/c mice and treated them with GM-CSF and IL-4 for 6 days. The MC-R profile on these immature dendritic cells was first determined by quantitative RT-PCR. Both transcripts for MC-1R and MC-5R were detected in these cells. Cells were subsequently stimulated with dinitrobenzene sulfonic acid (DNBS), ,-MSH or both substances for 2 or 16 h. After RNA preparation, cDNA synthesis and in vitro transcripton hybridization of biotinylated cRNA samples was performed on MG U74A Affymetrix gene chips. Data evaluation, cleansing, extraction and analysis of the more than 12 000 cloned genes and expressed sequence tags were performed using the GENE DATA ANALYST vs. 1 Expressionist software. Filter criteria included a minimum threshold of 100, normalization by the logarithmic mean and a quality setting of P < 0.04. Changes with a change factor of >2 were regarded as significant. As expected, stimulation with DNBS resulted in induction or upregulation of genes encoding proinflammatory cytokines, growth factors, signal transduction intermediates and transcription factors. Treatment with ,-MSH blocked the DNBS-driven upregulation of several known genes such as IL-1 or CD86. On the other hand, ,-MSH modulated the expression of several novel genes implicated in immunomodulation, e.g. IL-1, converting enzyme, IFN-, receptor, FK506-binding proteins or several neuropeptides and their receptors. These data indicate novel molecular targets by which ,-MSH exerts its immunomodulatory activities in immunocompetent cells. [source] From R&D to Innovation and Economic Growth in the EUGROWTH AND CHANGE, Issue 4 2004Beñat Bilbao-Osorio ABSTRACT Over the last two decades many European governments have pursued ambitious research and development (R&D) policies with the aim of fostering innovation and economic growth in peripheral regions of Europe. The question is whether these policies are paying off. Arguments such as the need to reach a minimum threshold of research, the existence of important distance decay effects in the diffusion of technological spillovers, the presence of increasing returns to scale in R&D investments, or the unavailability of the necessary socio-economic conditions in these regions to generate innovation seem to cast doubts about the possible returns of these sort of policies. This paper addresses this question. A two-step analysis is used in order to first identify the impact of R&D investment of the private, public, and higher education sectors on innovation (measured as the number of patent applications per million population). The influence of innovation and innovation growth on economic growth is then addressed. The results indicate that R&D investment, as a whole, and higher education R&D investment in peripheral regions of the EU, in particular, are positively associated with innovation. The existence and strength of this association are, however, contingent upon region-specific socio-economic characteristics, which affect the capacity of each region to transform R&D investment into innovation and, eventually, innovation into economic growth. [source] Bone mineralization defects and vitamin D deficiency: Histomorphometric analysis of iliac crest bone biopsies and circulating 25-hydroxyvitamin D in 675,patientsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2010Matthias Priemel Abstract Parathyroid hormone (PTH) is only one measurable index of skeletal health, and we reasoned that a histomorphometric analysis of iliac crest biopsies would be another and even more direct approach to assess bone health and address the required minimum 25-Hydroxyvitamin D [25(OH)D] level. A cohort from the northern European population with its known high prevalence of vitamin D deficiency therefore would be ideal to answer the latter question. We examined 675 iliac crest biopsies from male and female individuals, excluding all patients who showed any signs of secondary bone diseases at autopsy. Structural histomorphometric parameters, including osteoid indices, were quantified using the Osteomeasure System according to ASBMR standards, and serum 25(OH)D levels were measured for all patients. Statistical analysis was performed by Student's t test. The histologic results demonstrate an unexpected high prevalence of mineralization defects, that is, a pathologic increase in osteoid. Indeed, 36.15% of the analyzed patients presented with an osteoid surface per bone surface (OS/BS) of more than 20%. Based on the most conservative threshold that defines osteomalacia at the histomorphometric level with a pathologic increase in osteoid volume per bone volume (OV/BV) greater than 2% manifest mineralization defects were present in 25.63% of the patients. The latter were found independent of bone volume per trabecular volume (BV/TV) throughout all ages and affected both sexes equally. While we could not establish a minimum 25(OH)D level that was inevitably associated with mineralization defects, we did not find pathologic accumulation of osteoid in any patient with circulating 25(OH)D above 75,nmol/L. Our data demonstrate that pathologic mineralization defects of bone occur in patients with a serum 25(OH)D below 75,nmol/L and strongly argue that in conjunction with a sufficient calcium intake, the dose of vitamin D supplementation should ensure that circulating levels of 25(OH)D reach this minimum threshold (75,nmol/L or 30,ng/mL) to maintain skeletal health. © 2010 American Society for Bone and Mineral Research [source] Validation of diagnostic criteria for sleep bruxismJOURNAL OF ORAL REHABILITATION, Issue 9 2002K. BABA Several diagnostic criteria for bruxism can be taken from the literature; however, most of them have never been validated. This study examined whether predictor variables taken from physical examinations and questionnaires were related to the actual bruxism levels. Fifty dental students agreed to participate in this study and eight examination variables and seven questionnaire variables were collected from them. The subjects measured their nocturnal EMG activity from the right masseter muscle for six consecutive nights in their home by means of a portable EMG device. Off-line analysis was performed on data from second to sixth nights. By using a custom made software, all EMG activity elevations above a minimum threshold of 50% of each subject's individually established maximum voluntary contraction (MVC) level were quantified with regard to the duration and number of elevations and then three outcome variables, which were event number per hour (number/h), event duration per hour (duration h,1), and duration per event (duration/event), were calculated. A multiple stepwise regression (MSR) analysis was conducted to assess the 15 predictor variables and the three outcome variables. These MSR analyses revealed that the joint sound score remained in the regression equation as a predictor (n=50, P < 0·05) of the likelihood that a subject would exhibit longer bruxism events (duration h,1and number h,1). It must be noted that the self-awareness and tooth attrition status were found not to be strong predictors and even for the above variable where significant association was found, the likelihood ratio between the variable and predicted outcomes was not robust. [source] Discriminating raining from non-raining cloud areas at mid-latitudes using meteosat second generation SEVIRI night-time dataMETEOROLOGICAL APPLICATIONS, Issue 2 2008B. Thies Abstract A new method for the delineation of precipitation during night-time using multispectral satellite data is proposed. The approach is not only applicable to the detection of mainly convective precipitation by means of the commonly used relation between infrared cloud-top temperature and rainfall probability but enables also the detection of stratiform precipitation (e.g. in connection with mid-latitude frontal systems). The presented scheme is based on the conceptual model that precipitating clouds are characterized by a combination of particles large enough to fall, an adequate vertical extension [both represented by the cloud water path (CWP)], and the existence of ice particles in the upper part of the cloud. As no operational retrieval exists for Meteosat Second Generation (MSG) to compute the CWP during night-time, suitable combinations of brightness temperature differences (,T) between the thermal bands of Meteosat Second Generation-Spinning Enhanced Visible and InfraRed Imager (MSG SEVIRI, ,T3.9,10.8, ,T3.9,7.3, ,T8.7,10.8, ,T10.8,12.1) are used to infer implicit information about the CWP and to compute a rainfall confidence level. ,T8.7,10.8 and ,T10.8,12.1 are particularly considered to supply information about the cloud phase. Rain area delineation is realized by using a minimum threshold of the rainfall confidence. To obtain a statistical transfer function between the rainfall confidence and the channel differences, the value combination of the channel differences is compared with ground-based radar data. The retrieval is validated against independent radar data not used for deriving the transfer function and shows an encouraging performance as well as clear improvements compared to existing optical retrieval techniques using only IR thresholds for cloud-top temperature. Copyright © 2008 Royal Meteorological Society [source] 46 The feasibility of duodenum electrical stimulation to produce gastrointestinal symptoms in a clinical trialNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006KA STECCO Introduction:, Proximal duodenal electrical stimulation with various energy parameters has been investigated as a possible treatment for various gastrointestinal (GI) myoelectrical diseases. Wide pulse width (millisecond) stimulation in the proximal duodenum can disrupt or entrain the normal myoelectrical rhythm and provide a potential feedback pathway to alter normal gastric function such as emptying, fundus tone, and intra-gastric pressure and subsequently produce specific symptoms that could affect eating behaviors. A specific level of electrical stimulation is necessary to elicit symptoms and serve as an indicator that energy parameters are adequate. However, there has been no published data correlating electrical threshold stimulation with symptom characterization. The goal of this study was to determine the average minimum pulse width necessary to elicit GI symptoms. Methods:, Eight patients underwent endoscopic placement of intraluminal electrodes in the proximal duodenum. Each patient received electrical stimulation in the millisecond (ms) range starting with a pulse width of 100 ms that was increased by intervals of 100 ms up to a maximum pulse width of 500 ms. The pulse repetition frequency was fixed at 12 CPM and each regimen was repeated for amplitudes ranging from 2 milliamps (mA) to 10 mA. Gastrointestinal symptom scores consisting of nausea, vomiting, satiety, fullness, pain, bloating and other, were taken at baseline and after each regimen change. Results:, There was an average minimum threshold necessary for elicitation of symptoms (293.7 + 41.7 ms, p-value = 0.063). The three most frequently reported GI symptoms were crampy abdominal pain, fullness, and bloating. Conclusions:, Electrical stimulation of the duodenum is feasible. A certain minimum threshold of duodenal electrical stimulation is necessary to elicit GI symptoms in patients. The intensity and patient tolerability of each specific GI symptom was able to be adjusted by changing a certain energy parameter within a regimen. Further research is warranted to evaluate the ability of duodenal electrical stimulation to produce GI symptoms that may alter eating behaviors. [source] Phonon instability in nanocrystalline silicon carbidePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2006F. Cleri Abstract In recent experiments by a low-pressure, low-temperature technique, stable nanotubules of rocksalt SiC were synthetized in massive amounts. Ab-initio perturbative density-functional theory calculations in the bulk rocksalt phase provide evidence of drastic phonon softening at a critical pressure of about 2 GPa. To explain the exceptional persistence of the rocksalt structure at ambient conditions we propose that the high pressure induced by interfacial curvature may quench the phonon instability in the nanocrystals down to this minimum threshold, corresponding to the observed nanocrystal size of about 2 nm. Below such pressure the onset of mechanical instability forbids further growth and transformation to ordinary SiC. Nanocrystalline rocksalt SiC is a remarkable example of a material whose unstable, high-pressure phase is stabilized at ambient conditions upon reducing the grain size in the nanometre range. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mitochondrial Activity, Distribution and Segregation in Bovine Oocytes and in Embryos Produced in VitroREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2006AM Tarazona Contents Bovine oocytes and embryos produced in vitro were studied to determine the mitochondrial pattern of distribution, segregation and activity using DIOC 6 and Jc-1 fluorescence. The highest fluorescence level observed in mature oocytes was taken as 100% activity and six activity levels were estimated as follows: (1) 0%, (2) 1,15%, (3) 16,30%, (4) 31,50%, (5) 51,75% and (6) 76,100%. Three patterns of mitochondrial distribution were found: (1) diffused throughout the cytoplasm in oocytes and embryos, (2) pericytoplasmic in oocytes and embryos, and (3) perinuclear only in embryos. The segregation of mitochondria in blastomeres showed two distinct patterns: (1) symmetrical with an even mitochondrial population, and (2) asymmetrical with different numbers of mitochondria in each blastomere. In immature oocytes, mitochondrial activity was very low and the distribution was diffuse or negligible, while in mature oocytes the activity was high and the distribution was diffuse or pericytoplasmic. Competent embryos up to the 16-cell stage showed intermediate levels of activity (16,50%) but activity decreased thereafter up to the blastocyst stage. Non-competent embryos showed low levels of activity (1,15%) at all stages. These results suggest that mitochondria might play an important role during early development and that a minimum threshold of activity regulates the potential competence for reaching the blastocyst stage. [source] | ||||||||||