scholarly journals Comment on ‘Determination of the Radiocarbon Age of Parchment of the Vinland Map’

Radiocarbon ◽  
2002 ◽  
Vol 44 (2) ◽  
pp. 597-598
Author(s):  
K R Ludwig
Keyword(s):  
Weighted Average ◽  
Weighted Mean ◽  
Radiocarbon Age ◽  
Chemical Treatments ◽  
Statistical Errors

I wish to point out some statistical errors in the uncertainty calculations for the radiocarbon age of the Vinland Map (Donahue et al. 2002). First, the authors state that the 14C measurements of samples with chemical treatments B, C, D, and E “… result in consistent radiocarbon ages”, and that “… two (of these analyses) are 1.5 sigma, and the others are one sigma or less, from the weighted average.” In fact, the overall scatter of the data show that it is improbable that these data are statistically coherent, largely because analysis J21C lies 2.1 sigma from the weighted mean.

IPO Underpricing across Different Sectors in India from 2010-2020

2021 ◽  
pp. 337-345
Author(s):  
Lakshay Khandelwal ◽  
Aditi Agarwal
Keyword(s):  
Standard Deviation ◽  
Initial Public Offerings ◽  
Weighted Average ◽  
Weighted Mean ◽  
Ipo Underpricing ◽  
Consumer Durables ◽  
Engineering Construction ◽  
Public Offerings ◽  
Short Period ◽  
Indian Stock Market

In this paper, underpricing of Initial Public Offerings across thirteen different sectors in the Indian stock market have been analyzed, during the period 2010–2020 (Data available till 31st October 2020). A sample of 129 companies, having an issue size greater than INR 100 crores, was examined and analyzed through IPO listing gains, weighted mean, standard deviation and coefficient of variation. The study shows that Retail, FMCG and Consumer Durables industry was underpriced the most while Engineering, Construction and Infrastructure industry issues were underpriced the least or overpriced. It was also found that Initial Public Offerings (IPOs) could be a window to make immediate gains in a very short period of time if thorough analysis of the issues and the market conditions is performed. Furthermore, it was observed that the first day return of the companies varies highly and cannot be fairly predicted by the weighted average first day return of the respective sector.

scholarly journals C14 dating of Survey material performed in 1974

1975 ◽  
Vol 75 ◽  
pp. 19-20
Author(s):  
A Weidick
Keyword(s):  
New Jersey ◽  
Wood Sample ◽  
Field Work ◽  
Plant Anatomy ◽  
Radiocarbon Age ◽  
Apparent Age ◽  
Age Determinations

Thirteen radiocarbon age determinations of shell samples (12) and wood (1) are assembled in tbis account. The material dated was collected in connection with GGU field work. The samples have been dated at Isotopes Inc., Westwood, New Jersey, U.S.A. Determination of the wood sample was kindly made by Jette Dahl Møller, Institute of Plant Anatomy and Cytology, University of Copenhagen. Dating has also been carried out on a number of shelIs, dredged alive prior to 1950, in order to control the apparent age in shell dating determinations (Tauber & Funder, tbis report).

Effect of dispersible clay on the physical properties of the B horizon of a red-brown earth

Soil Research ◽  
1982 ◽  
Vol 20 (4) ◽  
pp. 315 ◽  
Author(s):  
RT Shanmuganathan ◽  
JM Oades
Keyword(s):  
Quantitative Characteristic ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Clay Particles ◽  
Chemical Treatments ◽  
Electrophoretic Mobilities ◽  
Dispersible Clay

Three methods were compared for the determination of dispersible clay in the absence of chemical treatments. Treatment of the B horizon of a red-brown earth with a range of amounts (0-0.24% iron) of iron poly[Fe(III)-OH] cations of nominal molecular weight 10 000 to 50 000 allowed production of a range of dispersible clay contents from 0 to 70%. The samples of clay B horizon with decreasing contents of dispersible clay showed decreasing electrophoretic mobilities with zero mobility when the content of dispersible clay was zero. In such samples the clay particles were present in aggregates 50-250 mu m diameter according to sedimentation techniques. The amounts of dispersible clay present appeared to control various physical and mechanical properties of the soil such as swelling, porosity and water retention capacity, hydraulic conductivity, friability and modulus of rupture. It is suggested that the content of dispersible clay may be a useful quantitative characteristic of soils as it controls many other properties.

scholarly journals Plant-Derived Natural Compounds for Tick Pest Control in Livestock and Wildlife: Pragmatism or Utopia?

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 490 ◽  
Author(s):  
Danilo G. Quadros ◽  
Tammi L. Johnson ◽  
Travis R. Whitney ◽  
Jonathan D. Oliver ◽  
Adela S. Oliva Chávez
Keyword(s):  
Natural Compounds ◽  
Tick Control ◽  
Wild Animal ◽  
Private Companies ◽  
The Road ◽  
Chemical Treatments ◽  
Animal Populations ◽  
The Right ◽  
Promising Avenue

Ticks and tick-borne diseases are a significant economic hindrance for livestock production and a menace to public health. The expansion of tick populations into new areas, the occurrence of acaricide resistance to synthetic chemical treatments, the potentially toxic contamination of food supplies, and the difficulty of applying chemical control in wild-animal populations have created greater interest in developing new tick control alternatives. Plant compounds represent a promising avenue for the discovery of such alternatives. Several plant extracts and secondary metabolites have repellent and acaricidal effects. However, very little is known about their mode of action, and their commercialization is faced with multiple hurdles, from the determination of an adequate formulation to field validation and public availability. Further, the applicability of these compounds to control ticks in wild-animal populations is restrained by inadequate delivery systems that cannot guarantee accurate dosage delivery at the right time to the target animal populations. More work, financial support, and collaboration with regulatory authorities, research groups, and private companies are needed to overcome these obstacles. Here, we review the advancements on known plant-derived natural compounds with acaricidal potential and discuss the road ahead toward the implementation of organic control in managing ticks and tick-borne diseases.

X-Ray Fluorescence Cross-Section Measurements in the Energy Range 4-18 keV

1995 ◽  
Vol 39 ◽  
pp. 845-855
Author(s):  
Krassimir N. Stoev ◽  
Joseph F. Dlouhy
Keyword(s):  
Cross Sections ◽  
Transition Probabilities ◽  
Weighted Average ◽  
Physical Parameters ◽  
Emission Rates ◽  
Excitation Energies ◽  
X Ray ◽  
Fluorescence Cross Section ◽  
Theoretical Results

K, L and M shell x-ray fluorescence cross sections have been measured for elements 11 ≤, Z ≤, 92 at excitation energies corresponding to weighted average energies of K-lines of Ti-K (4.558 keV), Fe-K (6,480 keV), Ge-K (10.024 keV), Se-K (11.391 keV) and Mo-K (17.805 keV) . The measurements were performed with an energy-dispersive x-ray spectrometer in a vacuum chamber using thin ultra-pure targets. Rh x-ray tube and secondary targets were used for excitation of x-ray radiation. The measured x-ray fluorescence cross-sections have been compared to previously published experimental and theoretical results. Presented data can be used for determination of physical parameters such as photoionization cross-sections, fluorescence yields, x-ray emission rates, Coster-Kronig transition probabilities and jump ratios.

scholarly journals Calculation and Prediction of the Total Glacial Melting in Watersheds of Central Asia

1977 ◽  
Vol 19 (81) ◽  
pp. 677-678
Author(s):  
V.G. Konovalov
Keyword(s):  
Solar Radiation ◽  
Atmospheric Precipitation ◽  
Weighted Average ◽  
Total Solar Radiation ◽  
Glacier Area ◽  
Glacier Surface ◽  
Seasonal Snow ◽  
Glacier Terminus ◽  
Snow Line

AbstractA computer method for calculating the total melting from May to October has been developed both for a single glacier and for a glacial area. In the second case (which is the more interesting and important for hydrology and glaciology) it is necessary to calculate some characteristics of an “average" glacier of the region using morphometric characteristics included in the Catalogue of the U.S.S.R. glaciers. These are: glacier area; average area of moraine on the glacier; weighted average of heights of upper and lower ends of a glacier and weighted average of mean height of firn line. It is also necessary to obtain data on glacier area distribution by height, precipitation data, and data on air temperature and cloudiness at meteorological stations.In addition to defining typical glacial regions within the limits of the glacial area considered and determination of the “average" glacier characteristics listed above, preparation of the computer programme includes (a) definition of precipitation dependence on orography height and calculation of appropriate parameters, (b) reduction (if necessary) of data obtained from the meteorological station nearest to glacial area to a more prolonged range, (c) calculation of a special balance index of accumulation and melting of seasonal precipitation which makes it possible to define maximum excess of seasonal snow line over the “average" glacier terminus in separate years, and (d) computation of total solar radiation occuring in clear days during May to October.In the course of computation on computer the following operations are realized: (a) determination of an average value of total radiation arriving during months of May to October period given the real cloudiness conditions, (b) calculation of the height of the snow line on the glacier, (c) calculation of quantity and duration of solid atmospheric precipitation which melts between May and October on the glacier surface, (d) estimation of absorbed solar radiation taking account of the differing albedo of glacial surfaces situated above and below the seasonal snow line, (e) calculation of the total melting of glaciers belonging to the given mountain watershed.Checking of the calculational method has been performed using data from Lednik Tsentralnyy Tuyuksu and Lednik Ayutor-2 where numerous ablation stakes were installed. Values of measured and calculated melting agree satisfactorily.

Use of image analysis to determine algal and bacterial biomass in a high rate algal pond following Percoll® fractionation

2003 ◽  
Vol 48 (2) ◽  
pp. 53-60 ◽  
Author(s):  
N.J. Cromar ◽  
H.J. Fallowfield
Keyword(s):  
Image Analysis ◽  
Gradient Centrifugation ◽  
Bacterial Biomass ◽  
Nutrient Status ◽  
High Rate ◽  
Carbon And Nitrogen ◽  
Chemical Treatments ◽  
Gravimetric Determination ◽  
Physical And Chemical

This paper reports the results of work to allow a more accurate enumeration, and gravimetric determination, of the relative proportions of algae and bacteria within the floccular matrix present in a High Rate Algal Pond (HRAP). Methodology involving a combination of physical and chemical treatments was used and the resulting material was separated using density gradient centrifugation. The “fractions” were analysed using microscopical image analysis. Each “fraction” was categorised as containing bacteria only, algae only or an association of bacteria and algae, the relative proportions of which were then determined by image analysis to enable a “true” gravimetric determination of the algal and bacterial components of HRAP biomass for the first time. The biomass from HRAPs operated both outdoors and in a glasshouse was examined over complete operational seasons to investigate environmental effects as well as possible effects of variation in COD loading rate and retention time on cell biovolumes and cell quotients. In this study, the accurate assessment of both algal and bacterial biomass, determined as cell volume or dry matter, in addition to measurement of carbon and nitrogen has enabled the calculation of cell quotients. This allows a direct comparison between these values obtained from a nutrient-rich system and those published values obtained from systems with various nutrient status. Conversion factors obtained may also be of value for deriving inputs for computer models for the design and operation of high rate algal ponds.

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