scholarly journals Determination of instream metal loads using tracer-injection and synoptic-sampling techniques, Wightman Fork, southwestern Colorado, July 1999

2001 ◽  
Author(s):  
Peter H. Wiebe ◽  
Ann Bucklin ◽  
Mark Benfield

This chapter reviews traditional and new zooplankton sampling techniques, sample preservation, and sample analysis, and provides the sources where in-depth discussion of these topics is addressed. The net systems that have been developed over the past 100+ years, many of which are still in use today, can be categorized into eight groups: non-opening/closing nets, simple opening/closing nets, high-speed samplers, neuston samplers, planktobenthos plankton nets, closing cod-end samplers, multiple net systems, and moored plankton collection systems. Methods of sample preservation include preservation for sample enumeration and taxonomic morphological analysis, and preservation of samples for genetic analysis. Methods of analysis of zooplankton samples include determination of biomass, taxonomic composition, and size by traditional methods; and genetic analysis of zooplankton samples.


2020 ◽  
Vol 14 (01) ◽  
pp. 13-22
Author(s):  
Sri Wahyuni

The purpose of this research is to study and to analyze the pattern of tourist destinations to determine the excellence of attractions in each district in the Special Region of Yogyakarta, as a tourist attraction. This research uses qualitative research methods with sampling techniques using positive sampling. Data sources used are informants, tourist attractions, and documents. Determination of the advantages of a tourist attraction in a regency and even in the Special Region of Yogyakarta aims to increase the selling power or visitors of a tourist attraction and become an icon or mascot in the regency or region in Yogyakarta Special Region. From the results of the discussion, it was concluded that the most preeminent in the Yogyakarta Special Region was Tourism, Beach and Temple Villages. Keywords: Tourist Patterns, Tourist Attraction, Tourist Asset, Potential Resources


1962 ◽  
Vol 28 (2) ◽  
pp. 234-238 ◽  
Author(s):  
Edward J. Olsen

AbstractThe X-ray spectrometer method as an archaeological tool is discussed with special reference to its limitations as a chemical analytical instrument. Qualitative results are presented for six North American copper samples, one European trade brass, and nine artifacts from the Great Lakes region. From this pilot study it is concluded that the most fruitful results in the problem of the determination of provenance of copper artifacts will be obtained from semi-quantitative optical spectographic analyses of carefully collected artifacts and raw materials. The largest inherent error in this problem is that of meaningful sampling techniques. The only recourse is to treat such chemical data statistically and determine the probabilities that given specimens came from the various possible sources.


2020 ◽  
pp. 3326-3339
Author(s):  
Nikant Sabharwal ◽  
Andrew Kelion ◽  
Theodoros Karamitos ◽  
Stefan Neubauer

Myocardial perfusion scintigraphy provides physiological information about the coronary circulation, in contrast to the anatomical information provided by angiography. Three radionuclide-labelled perfusion tracers are routinely used in single photon emission computed tomography (SPECT) imaging: thallium-201 and the technetium-99m-labelled complexes sestamibi and tetrofosmin. Imaging is performed following tracer injection during stress (exercise or pharmacological) and at rest; comparison allows determination of whether regional perfusion is normal, or if there is inducible hypoperfusion or infarction/scar. Myocardial perfusion imaging is minimally invasive, and—in contrast to other methods of investigation—can be performed regardless of overall exercise capacity, abnormalities of the resting electrocardiogram, pacemakers, obesity, claustrophobia, renal dysfunction, iodine allergy, or acoustic windows.


1966 ◽  
Vol 49 (5) ◽  
pp. 986-989
Author(s):  
J H P Dingle

Abstract Sampling techniques and an ultraviolet method, capable of handling large numbers of samples, have been developed for carbaryl in dipping fluids and cattle hair deposits. The absorbance (280 mμ) of dip samples is measured after suitable dilution with ethanol; a correction is made for the presence of 1-naphthol, but background interference from dip dirt, clay, cow dung, etc. is negligible at the dilutions used. The amount of carbaryl deposited on cattle hair dipping is estimated similarly after extraction with ethanol. The accuracy of the dip analysis and the effect of hair grease on the analysis of hair deposits are discussed.


2009 ◽  
Vol 2009 ◽  
pp. 67-67
Author(s):  
I Singh ◽  
W Hendriks ◽  
L Tucker ◽  
D G Thomas

Digestibility trials enable researchers to determine the amount of nutrients an animal absorbs and utilises from feed. There are a number of methods available, with the most common being the measurement of total feed intake and total collection of faeces. However, in situations where it is not practical to conduct a total collection trial, indigestible markers are used in conjunction with grab-sampling or sub-sampling techniques. To date, the most common marker used in dog studies has been chromium oxide (Cr2O3; Hill et al., 1996), with little data available on the suitability of other markers such as titanium dioxide (TiO2). A major problem in using Cr2O3 as an indigestible marker is poor repeatability and agreement between laboratories in the determination of Cr2O3. This has led to variable results due to incomplete and inconsistent recovery in excreta (Sales and Janssens, 2003). However work on other species comparing the use of TiO2 and Cr2O3, has demonstrated that TiO2 was a more accurate marker (Jagger et al., 1992). This study was performed to determine the digestibility of two diets, a low (LN) and a high nutrient (HN) diet using TiO2 or Cr2O3 as indigestible markers. The two different quality diets were used to investigate if digestibility affected marker recovery.


2000 ◽  
Vol 67 (1-3) ◽  
pp. 163-169 ◽  
Author(s):  
Balázs Tolnai ◽  
József Hlavay ◽  
Detlev Möller ◽  
Hans-Jörg Prümke ◽  
Hansjürgen Becker ◽  
...  

1995 ◽  
Vol 46 (7) ◽  
pp. 1047
Author(s):  
TP McBride ◽  
BN Noller

Sampling techniques were developed to measure trace-metal concentrations reliably in the shoots of a submerged macrophyte, Najas tenuifolia, and its attached periphyton growing in the Magela Creek flood plain in monsoonal northern Australia. At each site, 30 samples were collected within an 8-m by 8-m quadrat in a pattern of five samples from each of six irregularly spaced points. Samples were collected underwater to include all periphyton present, and precautions were taken at all stages of processing to avoid contamination. Periphyton was dislodged for separate chemical analysis by sonication followed by vigorous shaking. A significant aspect was the large amount of periphyton, up to 35% of the total sample dry weight, associated with the Najas sp. Only a proportion, up to 43%, of this periphyton could be dislodged by the physical procedures used. Trace metals were generally not present in the same concentrations in both the Najas sp. and the periphyton. The average trace-metal concentrations (μg g-1 dry weight) and standard errors measured in the Najas sp. (and periphyton) were cadmium 0.24 � 0.013 (0.093 � 0.012), copper 5.2� 0.25 (12 � 0.74), lead 0.93 � 0.084 (6.5 � 0.43), manganese 2500 � 110 (1500 � 110), uranium 0.24 � 0.023 (0.27 � 0.030), and zinc 38 � 1.0 (23 � 1.5). The significant differences in Najas sp. and periphyton trace-metal concentrations show the need to consider the effect of periphyton when sampling and reporting trace-metal concentrations in submerged macrophytes.


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