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Log normal distribution

Zijian Li
Exploring better models for evaluating the distribution of pesticide residues in soil and sediment is necessary to assess and avoid population health risk. Frequentist philosophy and probability are widely used in many studies to apply a log-normal distribution associated with the maximum likelihood estimation, which assumes fixed parameters and relies on a large sample size for long-run frequency. However, frequentist probability might not be suitable for analyzing pesticide residue distribution, whose parameters are affected by many complex factors and should be treated as unfixed...
October 9, 2018: Environment International
Madeleine D Hunter, Yeseon Park Moon, Charles DeCarli, Jose Gutierrez, Clinton B Wright, Marco R Di Tullio, Ralph L Sacco, Hooman Kamel, Mitchell S V Elkind
HYPOTHESIS: We hypothesized that P wave terminal Force in the V1 lead (PTFV1) would be associated with leukoaraiosis and subclinical infarcts, especially cortical infarcts, in a population-based, multi-ethnic cohort. METHODS: PTFV1 was collected manually from baseline electrocardiograms of clinically stroke-free Northern Manhattan Study participants. Investigators read brain MRIs for superficial infarcts, deep infarcts, and white matter hyperintensity volume (WMHV)...
2018: PloS One
José Aridiano Lima de Deus, Júlio César Lima Neves, Márcio Cleber de Medeiros Corrêa, Serge-Étienne Parent, William Natale, Léon Etienne Parent
The "Cavendish" and "Prata" subgroups represent respectively 47% and 24% of the world banana production. Compared to world average progressing from 10.6 to 20.6 t ha-1 between 1961 and 2016, and despite sustained domestic demand and the introduction of new cultivars, banana yield in Brazil has stagnated around 14.5 t ha-1 mainly due to nutrient and water mismanagement. "Prata" is now the dominant subgroup in N-E Brazil and is fertigated at high costs. Nutrient balances computed as isometric log-ratios (ilr) provide a comprehensive understanding of nutrient relationships in the diagnostic leaf at high yield level by combining raw concentration data...
October 9, 2018: Scientific Reports
Ding-Hui Peng, Jing Liu, Han-Ning Hu
OBJECTIVE: To explore the expression of EVI1 gene in AML and the ALL patients' bone marrow cells, and its correlation with the leukemic typing, clinical characteristics and prognosis. METHODS: Three hundred and thirty-three cases of leukemia in our hospital from 2012 to 2016 were enrolled in this study. Among them there were 263 cases of AML, 70 cases of ALL, and 13 volunteers were selected as normal controls. The bone marrow samples of the patients and volunteers were aspirated...
October 2018: Zhongguo Shi Yan Xue Ye Xue za Zhi
Saumyak Mukherjee, Sayantan Mondal, Subhajit Acharya, Biman Bagchi
Experiments have revealed that DNA solvation dynamics is characterized by multiple time scales ranging from a few ps to a few hundred ns and in some cases even up to several microseconds. The last part of decay is not only slow but can also be described by a power law (PL). The microscopic origin of this PL is yet to be clearly established. Here we present a theoretical study employing multiple approaches from time dependent statistical mechanics and computer simulations. The present study shows that water dynamics may not account for the slow PL decay because the longest timescales describing water dynamics could be at most of the order of 100 ps...
October 2, 2018: Journal of Physical Chemistry. B
Jelena Đuričić-Milanković, Ivan Anđelković, Ana Pantelić, Srđan Petrović, Andrea Gambaro, Dragana Đorđević
We have measured trace element contents in suburban aerosols from six size fractions in the range of PM0.27-16 from a background station in Belgrade (Serbia). The distribution and concentration of elements were determined within each of the investigated Dp fractions with emphasis on the fine and coarse modes. Fine/coarse mode ratios of element can provide information regarding their anthropogenic or natural origin. Analysis of seasonal variations of element contents in fine and coarse mode show that Cd, Co, K, and V have higher concentrations in the fine mode during heating season, while Fe contents are lower...
September 28, 2018: Environmental Monitoring and Assessment
Mateusz Jagła, Izabela Szymońska, Katarzyna Starzec, Olga Gach, Aneta Włodarczyk, Przemko Kwinta
BACKGROUND: Glucose variability (GV) is a matter of interest for researches in recent years. It is connected with oxidative stress, which is crucial in the development of multiple complication of prematurity. However, glycemic variability in preterm infants was poorly investigated. This study aims to investigate glycemic variability obtained from a continuous glucose monitoring (CGM) system in a cohort of very low-birthweight (VLBW) infants. METHODS: A prospective, single-center, open cohort study enrolled 74 VLBW infants with a mean birthweight of 1066 g and median gestational age of 28 weeks...
September 21, 2018: Diabetes Technology & Therapeutics
Brooke E Magnus, Yang Liu
This research introduces a latent class item response theory (IRT) approach for modeling item response data from zero-inflated, positively skewed, and arguably unipolar constructs of psychopathology. As motivating data, the authors use 4,925 responses to the Patient Health Questionnaire (PHQ-9), a nine Likert-type item depression screener that inquires about a variety of depressive symptoms. First, Lucke's log-logistic unipolar item response model is extended to accommodate polytomous responses. Then, a nontrivial proportion of individuals who do not endorse any of the symptoms are accounted for by including a nonpathological class that represents those who may be absent on or at some floor level of the latent variable that is being measured by the PHQ-9...
October 2018: Applied Psychological Measurement
Wenying Meng, Pu Wang, Ruiqiang Yang, Huizhong Sun, Julius Matsiko, Dou Wang, Peijie Zuo, Yingming Li, Qinghua Zhang, Guibin Jiang
Surface soil samples were collected from Mt. Sygera in the southeast of Tibetan Plateau to investigate the altitudinal distribution of PCBs and PBDEs along the two sides of the mountain. The average concentrations of PCBs and PBDEs were 177 pg g-1 dw and 15 pg g-1 dw, respectively. The relationships between the log-transformed TOC-normalized concentrations and the altitudes showed different trends on the two sides. On the windward side, there was a positive correlation for the heavier PCBs; while on the leeward side, the concentrations increased and then decreased for PCBs and PBDEs at the altitude of 4100-4200 m, corresponding to the change in vegetation...
September 19, 2018: Scientific Reports
Emma E Lannergård, José L J Ledesma, Jens Fölster, Martyn N Futter
Surface water eutrophication resulting from excessive phosphorus (P) inputs is one of today's most challenging environmental issues. Riverine total phosphorus (TP) concentrations have high temporal variability, which complicates flux estimation. We evaluated the usefulness of high frequency in-situ turbidity measurements as a proxy for TP in Sävjaån, a river draining a mixed land use catchment (722 km2 ) in central Sweden. Turbidity was monitored every 10th-15th minute during 6 consecutive years (2012-2017)...
September 11, 2018: Science of the Total Environment
Rodrigo Ottoni, Jason A Griggs, Pedro H Corazza, Álvaro Della Bona, Márcia Borba
This study aimed to characterize the fatigue behavior using two fatigue methods, boundary and staircase, and to predict the probability of failure (Pf ) of zirconia-reinforced lithium silicate glass-ceramic (ZLS). Bar-shaped specimens of ZLS (18 ×4 ×1.2 mm) were fabricated. Thirty specimens were subjected to a three-point flexural strength test using a universal testing machine with 0.5 mm/min crosshead speed, in 37 °C distilled water. Flexural strength data were analyzed with Weibull statistics...
September 5, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Christopher Burton, Alison Elliott, Amanda Cochran, Tom Love
BACKGROUND: The science of complex systems has been proposed as a way of understanding health services and the demand for them, but there is little quantitative evidence to support this. We analysed patterns of healthcare use in different urgent care settings to see if they showed two characteristic statistical features of complex systems: heavy-tailed distributions (including the inverse power law) and generative burst patterns. METHODS: We conducted three linked studies...
September 7, 2018: BMC Medicine
Belinda Spratt, Erhan Kozan, Michael Sinnott
Objective Analytical techniques are being implemented with increasing frequency to improve the management of surgical departments and to ensure that decisions are well informed. Often these analytical techniques rely on the validity of underlying statistical assumptions, including those around choice of distribution when modelling uncertainty. The aim of the present study was to determine a set of suitable statistical distributions and provide recommendations to assist hospital planning staff, based on three full years of historical data...
September 6, 2018: Australian Health Review: a Publication of the Australian Hospital Association
Hamza Gerçekcioğlu
Using the Rytov method, bit error rate (BER) performances of M-pulse amplitude modulation (M-PAM) are investigated for a flat-topped beam when such a beam is employed in an aeronautical laser communication system operating in vertical paths having weak atmospheric turbulence. By using the on-axis scintillation index and the log-normal distributed intensity, the average BER (⟨BER⟩) is evaluated for M-PAM when M=2,4,8. The scintillation indices of collimated flat-topped beams of various flatness orders N are compared against propagation lengths, source sizes, and zenith angle for laser communication vertical paths, including uplink and downlink...
September 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Li Sheng Tang, Hua Wang, Wei Qin Liu, Ye Liu
Chilling is the third weather disaster following flood and typhoon in Guangdong Province. Prediction of chilling return period is of practical significance for scientific reduction and protection of disaster. Four models, including Gumbel distribution, Weibull distribution, log-normal distribution and Peasron-III distribution, were applied, based on the chilling index, to fit the probability distribution of chilling extreme calculated by chilling accumulation for 86 weather stations of Guangdong Province from 1961 to 2015 (December to the following February)...
August 2018: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
Herut Uzan, Shira Sardi, Amir Goldental, Roni Vardi, Ido Kanter
Experimental evidence recently indicated that neural networks can learn in a different manner than was previously assumed, using adaptive nodes instead of adaptive links. Consequently, links to a node undergo the same adaptation, resulting in cooperative nonlinear dynamics with oscillating effective link weights. Here we show that the biological reality of stationary log-normal distribution of effective link weights in neural networks is a result of such adaptive nodes, although each effective link weight varies significantly in time...
August 30, 2018: Scientific Reports
K Evert-Arriagada, A J Trujillo, G G Amador-Espejo, M M Hernández-Herrero
In this study, both microbial inactivation and growth of Listeria spp. inoculated in commercial free-starter fresh cheese was evaluated after high-pressure processing (HPP). HPP conditions (300, 400, 500 and 600 MPa at 6 °C for 5 min) and inoculum level (3-4 or 6-7 log CFU/g of cheese), as well as differences among strains inoculated (Listeria innocua, L. monocytogenes CECT 4031 and L. monocytogenes Scott A) were investigated. Inactivation and generation of sublethal injury were determined after HPP using ALOA (Agar Listeria according to Ottaviani and Agosti) and TAL (Thin Agar Layer) plating methods, respectively...
December 2018: Food Microbiology
Tatsuya J Arai, Felix C Horn, Rui Carlos Sá, Madhwesha R Rao, Guilhem Jean Collier, Rebecca J Theilmann, Gordon Kim Prisk, Jim M Wild
Two magnetic resonance specific ventilation imaging (SVI) techniques namely, oxygen enhanced proton (OE-1H) and hyperpolarized 3 He (HP-3He) were compared in eight healthy supine subjects (age 32(6) yr). An in-house radio-frequency coil array for 1 H configured with the 3 He transmit-receive coil in-situ enabled acquisition of SVI data from two nuclei from the same slice without repositioning the subjects. Following 3×3 voxel-down-sampling to account for spatial registration errors between the two SV images, the voxel-by-voxel correlation coefficient of two SV maps ranged from 0...
August 30, 2018: Journal of Applied Physiology
Jie Gao, Peng Zhang, Xing Zhang, Yanhong Liu
In order to better explore the maintenance mechanisms of biodiversity, data collected from a 40-ha undisturbed Pinus forest were applied to the Individual Species-Area Relationship model (ISAR) to determine distribution patterns for species richness. The ecological processes influencing species abundance distribution patterns were assessed by applying the same data set to five models: a Log-Normal Model (LNM), a Broken Stick Model (BSM), a Zipf Model (ZM), a Niche Preemption Model (NPM), and a Neutral Model (NM)...
April 2018: Plant Diversity
Shinichiro Tomitaka, Yohei Kawasaki, Kazuki Ide, Maiko Akutagawa, Yutaka Ono, Toshiaki A Furukawa
BACKGROUND: Previous studies have shown that item responses and total scores on depression screening scales follow characteristic distribution patterns in the United States and Japanese general populations. However, the degree to which these findings, especially in terms of item responses, can be generalized to a European population is unknown. Thus, we analyzed the item responses and total score distribution for the Center for Epidemiologic Studies Depression Scale (CES-D) in a representative Irish cohort from a large, recent study-the Irish Longitudinal Study on Ageing (TILDA)...
2018: PloS One
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