Aspects of the chemical variability of some Tasmanian inland waters

1976 ◽  
Vol 27 (3) ◽  
pp. 351 ◽  
Author(s):  
RT Buckney
Keyword(s):  
Total Concentration ◽  
Inland Waters ◽  
Morphometric Characters ◽  
Fresh Waters ◽  
Ionic Concentrations ◽  
Geological Conditions ◽  
Chemical Variability ◽  
Saline Waters ◽  
The Mean ◽  
Standard Deviations

Variability of total concentration and of ionic concentrations (measured as the standard deviations) is proportional to a power of the mean concentrations in 25 Tasmanian waters. Stoichiometric variability is low in saline waters and can be high in fresh waters. Climate is recognized as being of primary importance in affecting variability, although morphometric characters exert an influence. Geological conditions are an important factor in determining stoichiometric variability.

scholarly journals The Probability That a Measurement Falls within a Range of Standard Deviations from an Estimate of the Mean

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Louis M. Houston
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
General Equation ◽  
Sample Sizes ◽  
The Mean ◽  
Standard Deviations ◽  
Intermediate Value ◽  
Theoretical Results

We derive a general equation for the probability that a measurement falls within a range of n standard deviations from an estimate of the mean. So, we provide a format that is compatible with a confidence interval centered about the mean that is naturally independent of the sample size. The equation is derived by interpolating theoretical results for extreme sample sizes. The intermediate value of the equation is confirmed with a computational test.

The Distribution of Chaetognatha in the Gulf of Alaska in 1954 and 1956

1959 ◽  
Vol 16 (3) ◽  
pp. 351-361 ◽  
Author(s):  
Paul N. Sund
Keyword(s):  
Coastal Region ◽  
Gulf Of Alaska ◽  
Inland Waters ◽  
San Juan ◽  
Frequency Of Occurrence ◽  
Subarctic Region ◽  
Saline Waters ◽  
Hydrographic Features

Zooplankton collections from two cruises to the Gulf of Alaska during 1954 and 1956 were studied to determine the species of Chaetognatha present, to establish their distribution within those waters, and to consider the distribution of the species with regard to certain general hydrographic features prevalent in the region at the time the collections were made. Also considered were a few collections made during the summer of 1958 in the waters surrounding San Juan Island in the San Juan Archipelago, Washington.The general oceanographic features of the Gulf of Alaska are described. The distributions and frequency of occurrence of 3 species of 2 genera of chaetognatha are described and discussed. Eukrohnia hamata is found at most off-shore stations, diminishing in number nearer the coast in less saline waters. Sagitta elegans is apparently cosmopolitan in the areas studied. S. lyra an oceanic form, was found in regions influenced by waters of the Subarctic Region and the American Coastal Region. The presence of S. lyra in inland waters of the San Juan Archipelago during the summer of 1958 is considered to be an indication of the shoreward movement of oceanic waters.

HEAD CIRCUMFERENCE, MENTAL RETARDATION, AND GROWTH FAILURE

PEDIATRICS ◽  
1965 ◽  
Vol 36 (1) ◽  
pp. 62-66
Author(s):  
Edward J. O'Connell ◽  
Robert H. Feldt ◽  
Gunnar B. Stickler
Keyword(s):  
Mental Retardation ◽  
Head Circumference ◽  
Growth Failure ◽  
Clinical Impression ◽  
Severe Mental Retardation ◽  
Small Head ◽  
The Mean ◽  
Standard Deviations ◽  
Mental Subnormality ◽  
Age And Sex

The purpose of this study was to re-affirm our clinical impression that non-institutionalized children whose head circumference was below minus 2 standard deviations were mentally subnormal and frequently had growth failure. A group of 134 children with a head circumference below minus 2 standard deviations from the mean were studied, and all but one were mentally subnormal. The most severe mental retardation was noted in the group of children with a head circumference of minus 4 standard deviations or below. We found, as have others, that children with mental retardation have height and weights below the expected norm and that children with a head circumference below minus 2 standard deviations have even lower mean heights and weights. The head circumference of 31 children with growth failure and normal intelligence was normal for age and sex, therefore disproving the concept that the abnormally small child has a proportionally small head. In the child with growth failure, should the head be proportionally small (below minus 2 standard deviations), mental subnormality should be suspected. We feel that the head circumference measurement has taken on new clinical significance in that our data support its use in suspecting the association of mental subnormality in children with growth failure and a head circumference of below minus 2 standard deviations from the mean for age and sex.

scholarly journals Physico-chemical variability and heavy metal pollution of surface sediment in a non-channeled section of Dilúvio Stream (Southern Brazil) and the influence of channeled section in sediment pollution

2019 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Pedro Alexandre Sodrzeieski ◽  
Leonardo Capeleto de Andrade ◽  
Tales Tiecher ◽  
Flávio Anastácio de Oliveira Camargo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Total Concentration ◽  
Mineralogical Composition ◽  
Sediment Pollution ◽  
Anthropogenic Influence ◽  
Southern Brazil ◽  
Physico Chemical ◽  
Chemical Variability ◽  
The Impact

Dilúvio Stream flows through an area with a great population density in Porto Alegre, Southern Brazil. The anthropogenic influence in the surroundings impacted negatively the quality of the sediments of Dilúvio Stream and Lake Guaíba. This study evaluated the physico-chemical variability of surface sediments in a non-channeled section of Dilúvio Stream. Additionally, we compared the concentration of several heavy metals in this section with data from previous studies in the margins of Lake Guaíba near the outflow of Dilúvio Stream in order to evaluate the impact of urbanization on sediment pollution. The pH, bulk density, particle-size distribution, electrical conductivity, organic carbon, assimilable phosphorus, total nitrogen, mineralogical composition (X-ray diffractogram) and pseudo total concentration of several metals (Fe, Al, Ca, Mg, Na, K, Mn, Ba, Zn, V, As, Pb, Cu, Cr, Co, Ni, Cd, Mo, and Se) were evaluated. The results showed that the sediments in the non-channeled section of Dilúvio Stream are predominantly sandy, with heavy metal contents below the quality reference values. Quartz and feldspar predominated in all sites. The concentration of Zn, Pb, Cu, Cr, and Ni were lower than that observed in the margins of Lake Guaíba near the outflow of Dilúvio Stream, possibly due to pollution input throughout the channeled section. The Dilúvio Stream shows indications of an anthropogenic influence in the heavy metals concentration through the channeled area.

Legibility Study of Selected Scale Characteristics for Moving-Tape Instruments

1965 ◽  
Vol 7 (6) ◽  
pp. 545-555 ◽  
Author(s):  
Barbara J. Kelso
Keyword(s):  
Air Force ◽  
Reaction Times ◽  
Scale Factor ◽  
Verbal Response ◽  
Scale Factors ◽  
Scale Characteristics ◽  
The Mean ◽  
Standard Deviations ◽  
Vertical Scales ◽  
Speed And Accuracy

A legibility study was performed to investigate the effects of scale factors, graduation marks, orientation of scales, and reading conditions on the speed and accuracy of reading moving-tape instruments. Each of 150 Air Force Officers made 150 self-paced readings from slides of hand drawn tape instruments. Error was expressed as the magnitude of deviation of a subjects' verbal response from the set scale value. An analysis of variance was performed on the mean error scores, standard deviations of error, mean reaction times, and standard deviations of reaction times. The results clearly favored the 1 7/8 inch scale factor over the 1 3/8 inch and the 2 3/8 scale factor. The use of 9 graduation marks was superior to either 0, 1, 3, or 4 graduation marks. Reading conditions had little effect on performance. Horizontal scales were read more rapidly but no more accurately than vertical scales.

The Effects of Ethyl Alcohol on a Driver's Driving Skill, Visual Perception, Risk Acceptance, Choice Reaction Times and Information Processing Rates

1974 ◽  
Vol 18 (2) ◽  
pp. 116-116
Author(s):  
Helmut T. Zwahlen
Keyword(s):  
Information Processing ◽  
Standard Deviation ◽  
Visual Perception ◽  
Reaction Times ◽  
Driving Skill ◽  
Alcohol Condition ◽  
The Mean ◽  
Risk Acceptance ◽  
Standard Deviations ◽  
Choice Reaction Times

Twelve subjects (20–37 years old) were tested in the laboratory and eleven out of these were also tested in a car in the field, first under a no alcohol condition and then under an alcohol condition (approximately 0.10% BAC). In the laboratory the subjects simple and choice reaction times for two uncertainty modes were measured and their information processing rates (3 bits unsertainty) were determined. In the field the subjects driving skill for driving through a gap with 20 inches total clearance at 20 MPH was measured, as well as their static visual perceptual capabilities and risk acceptance decisions for a 46 feet viewing distance using psychophysical experimental methods. Based upon the driving skill measure (standard deviation of centerline deviations in the gap), the mean of the psychometric visual gap perception function and the mean of the psychometric gap risk acceptance function, the “Safety Distance” and the “Driver Safety Index” (DSI) were obtained. Based upon a statistical analysis of the data we may conclude first that the effects of alcohol (approximately 0.10% BAC) vary widely from one subject to another (slighthly improved performance to highly impaired performance) and that the changes in the group averages of the means and standard deviations of the psychometric visual perception and risk acceptance functions, the driving skill distributions, the “Safety Distances” and the DSI's for the subjects (although all changes in the group averages are in the expected direction) are statistically not significant (α = .05). Second, the group average of the means of the choice reaction times for the subjects increased by 5% under the alcohol condition (statistically significant, α = .05), but more important the group average of the standard deviations of the choice reaction times for the subjects increased by 23% (statistically significant, α = .05). The group average of the information processing rates for the subjects decreased by 3% (statistically not significant, α = .05) under the alcohol condition. A system model in which the system demands on the driver are represented in terms of choice reaction times is used to demonstrate that the increase in performance variability (expressed by the standard deviation of choice reaction times) under the influence of alcohol provides a much better explanation for the higher accident involvement than the historically most frequently used rather small increase in average performance (expressed by the mean of choice reaction times).

scholarly journals Academic and Administrative Attitude of Prospective Teachers Towards Teaching Profession

2020 ◽  
Vol 5 (9) ◽  
pp. 786-789
Author(s):  
Dr. Albert S. Tirkey
Keyword(s):  
Prospective Teachers ◽  
Healthy Person ◽  
Attitude Scale ◽  
Teaching Profession ◽  
Z Score ◽  
The Mean ◽  
Standard Deviations ◽  
Garo Hills

Education seeks to develop the innate inner capacities of man. The ultimate goal of education is to prepare the students to be responsible and mentally healthy person to live on this earth. In order to achieve this, students are to be molded only by making them experience the significance of values in the school itself. In most of the cases education takes place under the guidance of teachers. Teachers are the biggest influencers in a student’s life. Their personality and attitudes contribute to a great extend in students learning. In this respect, determining the attitude of prospective teachers towards teaching profession is of great importance. The main objectives of this paper are to test: academic attitude of prospective teachers towards teaching profession; and administrative attitude of prospective teachers towards teaching profession. Tool used for the study was ‘attitude scale towards teaching’, developed by Dr. (Mrs.) Ummen Kulsum. In order to analyze the data, Z-score in terms of standard deviations from the mean was used. The study was delimited to West Garo Hills District of Meghalaya.

scholarly journals Longitudinal anthropometric assessment of infants born to HIV-1-infected mothers, Belo Horizonte, Southeastern Brazil

2011 ◽  
Vol 45 (4) ◽  
pp. 652-660 ◽  
Author(s):  
Maria Arlene Fausto ◽  
Mariângela Carneiro ◽  
Carlos Maurício F Antunes ◽  
Enrico Antonio Colosimo ◽  
Jorge Andrade Pinto
Keyword(s):  
Growth Parameters ◽  
Nutritional Risk ◽  
Southeastern Brazil ◽  
Continuous Assessment ◽  
Nutritional Interventions ◽  
The Mean ◽  
Standard Deviations ◽  
Belo Horizonte ◽  
Mean Differences ◽  
Hiv 1

OBJECTIVE: To evaluate the growth parameters in infants who were born to HIV-1-infected mothers. METHODS: The study was a longitudinal evaluation of the z-scores for the weight-for-age (WAZ), weight-for-length (WLZ) and length-for-age (LAZ) data collected from a cohort. A total of 97 non-infected and 33 HIV-infected infants born to HIV-1-infected mothers in Belo Horizonte, Southeastern Brazil, between 1995 and 2003 was studied. The average follow-up period for the infected and non-infected children was 15.8 months (variation: 6.8 to 18.0 months) and 14.3 months (variation: 6.3 to 18.6 months), respectively. A mixed-effects linear regression model was used and was fitted using a restricted maximum likelihood. RESULTS: There was an observed decrease over time in the WAZ, LAZ and WLZ among the infected infants. At six months of age, the mean differences in the WAZ, LAZ and WLZ between the HIV-infected and non-infected infants were 1.02, 0.59, and 0.63 standard deviations, respectively. At 12 months, the mean differences in the WAZ, LAZ and WLZ between the HIV-infected and non-infected infants were 1.15, 1.01, and 0.87 standard deviations, respectively. CONCLUSIONS: The precocious and increasing deterioration of the HIV-infected infants' anthropometric indicators demonstrates the importance of the early identification of HIV-infected infants who are at nutritional risk and the importance of the continuous assessment of nutritional interventions for these infants.

scholarly journals Components of litter size in mice after 110 generations of selection

Reproduction ◽  
2004 ◽  
Vol 127 (5) ◽  
pp. 587-592 ◽  
Author(s):  
M Holt ◽  
O Vangen ◽  
W Farstad
Keyword(s):  
Litter Size ◽  
Late Pregnancy ◽  
Ovulation Rate ◽  
Control Line ◽  
Embryo Survival ◽  
High Line ◽  
Line Selection ◽  
Males And Females ◽  
The Mean ◽  
Standard Deviations

The aim of the present study was to evaluate how ovulation rate and survival rate through pregnancy had been affected by more than 110 generations of upwards selection on litter size in mice. The mean number of pups born alive was 22 in the high line (selected line) and 11 in the control line (an increase in 2.6 standard deviations). Selection on litter size increased ovulation rate by 4.6 standard deviations, and it is suggested that selection also increased embryonic mortality in late pregnancy. Embryo survival from ovulation until birth was 66% in the selected line and 69% in the control line, and the observed loss in litter size from day 16 of pregnancy until birth was possibly higher in the high line compared with the control line. Selection for higher litter size has significantly increased body weight in both males and females, as the mean weight at mating for the females was 46 g in the high line and 33 g in the control line respectively.

OBSERVATIONS OF TOTAL SERUM BASE IN CHILDREN AND YOUNG ADULTS BY A CONDUCTIVITY METHOD

PEDIATRICS ◽  
1949 ◽  
Vol 4 (6) ◽  
pp. 805-809
Author(s):  
W. M. KELSEY ◽  
L. B. LEINBACH
Keyword(s):  
Young Adults ◽  
Total Serum ◽  
Age Group ◽  
Conductivity Method ◽  
Normal Children ◽  
Significant Difference ◽  
Children And Young Adults ◽  
The Mean ◽  
Standard Deviations

Values for total serum base in 96 normal children under 12 years of age as determined by the conductivity method fell between 143 to 160.5 mEq./l. The mean was 153. Standard deviations for each age group are given. The values in 73 normal persons above the age of 12 varied from 142 to 160.5 mEq./l. The mean was 147 mEq./l. A statistically significant difference between the total serum base in children and adults was found.

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