Some Sampling Problems in Fishery Work

Biometrics ◽  
1971 ◽  
Vol 27 (3) ◽  
pp. 631 ◽  
Author(s):  
Patrick K. Tomlinson
Keyword(s):  
Sampling Problems

Overcoming Gas Sampling Problems: Analysis of Volatiles Using Capillary Column Needles

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 643f-643
Author(s):  
Weimin Deng ◽  
Randolph M. Beaudry
Keyword(s):  
Stainless Steel ◽  
Capillary Column ◽  
Dependent Manner ◽  
Stainless Steel Capillary ◽  
Stainless Steel Needle ◽  
Injection Volume ◽  
Volatile Analysis ◽  
Gas Tight ◽  
Sampling Problems ◽  
Time Injection

Sampling factors that could affect gas chromatograph (GC) response for volatile analysis such as syringe pumping time, injection volume, needle length, temperature, and the type of volatile were investigated. Capillary GC column segments (steel and glass) were installed in gas-tight syringes and used as needles for volatile analysis. Standard stainless-steel needles were also used. Hexylacetate, ethyl-2-methylbutyrate, 6-methyl-5-hepten-2-one, and butanol standard were measured. The number of pumps required to maximize GC response for each needle–volatile combination was determined. Maximal GC response for hexylacetate using standard stainless steel, capillary glass, and capillary steel needles required 10, 20 and 30 pumps, respectively. However, for butanol measurement, the optimal syringe pump number was 5 to 10 for all needle types. The use of a capillary needle resulted in an increase in GC response in the range of 3- to 15-fold relative to a standard stainless steel needle. Injection volume affected GC response in a needle-and volatile-dependent manner. In no case did injection volume vs. GC response extrapolate through origin. The GC response for capillary column needles increased as temperature decreased. Capillary column needles may be useful tools for analysis of volatiles that readily partition into the column coating.

scholarly journals Do We Need to Use Bats as Bioindicators?

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 693
Author(s):  
Danilo Russo ◽  
Valeria B. Salinas-Ramos ◽  
Luca Cistrone ◽  
Sonia Smeraldo ◽  
Luciano Bosso ◽  
...  
Keyword(s):  
Scientific Evidence ◽  
Legal Obligation ◽  
Farming Practices ◽  
Population Declines ◽  
Technological Advances ◽  
River Quality ◽  
Surrogate Taxa ◽  
Available Information ◽  
Sampling Problems ◽  
The Eu

Bats show responses to anthropogenic stressors linked to changes in other ecosystem components such as insects, and as K-selected mammals, exhibit fast population declines. This speciose, widespread mammal group shows an impressive trophic diversity and provides key ecosystem services. For these and other reasons, bats might act as suitable bioindicators in many environmental contexts. However, few studies have explicitly tested this potential, and in some cases, stating that bats are useful bioindicators more closely resembles a slogan to support conservation than a well-grounded piece of scientific evidence. Here, we review the available information and highlight the limitations that arise in using bats as bioindicators. Based on the limited number of studies available, the use of bats as bioindicators is highly promising and warrants further investigation in specific contexts such as river quality, urbanisation, farming practices, forestry, bioaccumulation, and climate change. Whether bats may also serve as surrogate taxa remains a controversial yet highly interesting matter. Some limitations to using bats as bioindicators include taxonomical issues, sampling problems, difficulties in associating responses with specific stressors, and geographically biased or delayed responses. Overall, we urge the scientific community to test bat responses to specific stressors in selected ecosystem types and develop research networks to explore the geographic consistency of such responses. The high cost of sampling equipment (ultrasound detectors) is being greatly reduced by technological advances, and the legal obligation to monitor bat populations already existing in many countries such as those in the EU offers an important opportunity to accomplish two objectives (conservation and bioindication) with one action.

A note on sampling technique for winter oil-seed rape (Brassica napus L.)

1982 ◽  
Vol 99 (1) ◽  
pp. 225-227 ◽  
Author(s):  
D. H. Scarisbrick ◽  
A. Clewer ◽  
R. W. Daniels
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Nitrogen Fertilizer ◽  
Yield Components ◽  
Sampling Technique ◽  
Brassica Napus L ◽  
Plant Weight ◽  
Oil Seed ◽  
Oil Seed Rape ◽  
Sampling Problems

The response of three spring cultivars of oilseed rape to five levels of nitrogen fertilizer (0 to 200 kg/ha) was studied during 1978–9 (Scarisbrick, Daniels & Alcock, 1981). Sampling problems, practical difficulties of measuring yield components, and the high co-efficients of variation for these data were discussed. During the course of further investigations on the winter cultivar Jet Neuf (established on approximately 75000 ha in the U. K. during 1980–1) within-plot variability for plant weight was assessed in order to indicate the size of sample necessary to compare treatment means.

efficiency. By measurements of total odour strength in a treatment plant the ED values pointed out the sludge press and dewatering process as the predominant odour sources of the plant. In the venting air from this position extremely high ED values were recorded. This air was led through a carbon filter for odour reduction. Olfactometric measurements at the filter revealed poor odour reducing efficiency. It was observed that odour compounds were not destroyed in the filter. They only restrained until the carbon became saturated, and thereafter evaporated into the outlet air contributing to the odour strength. The filter capacity was obviously too small for the heavy load. Attempts to reduce the odour strength before the filter did not succeed, until the air was led through a container filled with saturated lime slurry (pH = 12-14). The slurry was part of a precipitation process in the plant. Dispersion in the alkaline slurry extensively reduced the odour strength of the air, resulting in sufficient capacity of the carbon filter also when handling heavy loads of sewage sludge. Since then the carbon filter has worked well, within the limitation of such filters in general. Neither is it observed signs indicating reduced precipitation properties of the lime slurry. Measurements of total odour strength in combustion processes imply sampling challenges. Beside the chemical scrubber process, combustion of odorous air is the best odour reducing method. The disadvantage of this process is the high energy costs. Treatment at apropriate conditions, however, will destroy the odorous compounds extensively. Temperatures about 850 C and contact time up to 3 seconds are reported (2,3). Olfactometric measurements in combustion processes involve certain sampling problems caused by the temperature difference between inlet and outlet. The humidity of outlet air must also be taken into consideration. Problems may occur when hot outlet air is sampled at low temperatures. In most such cases sampling is impossible without special arrangements. Such conditions are present during odour measurements in fish meal plants with combustion as the odour reducing method. The largest problem turned out to be the temperature differences between outlet air (85-220 C) and outdoor temperatures (0-15 C), causing condensation. The dew point of the outlet air was calculated, and experiments were carried out with dilution of the outlet air to prevent condensation in the sampling bags. Condensation was prevented by diluting the outlet air 5-150 times with dry, purified N gas. Comparison of N -diluted and undiluted samples revealed large differences in ED value. In samples demanding a high degree of dilution to prevent condensation, the measured odour strength was up to 5 times higher than in the undiluted corresponding samples. Samples demanding less dilution showed less deviating results. 4. CONCLUSIONS In the attempt to minimize odour emission, olfactometric measurements of total odour strength give useful informations about the odour reducing efficiency of different processes as a function of parameters like dosage of chemicals in scrubbers, humidity and temperature in packed filters, flow rates, etc. Olfactometric measurements also point out the main odour sources of the plant. From a set of olfactometric data combined with other essential

1986 ◽  
pp. 98-98
Keyword(s):  
Treatment Plant ◽  
High Energy ◽  
Dew Point ◽  
Precipitation Process ◽  
Heavy Load ◽  
Heavy Loads ◽  
Combustion Processes ◽  
Sampling Problems ◽  
High Degree ◽  
Carbon Filter

Quantitative ultrastructural analysis in cardiac membrane physiology

1978 ◽  
Vol 235 (5) ◽  
pp. C147-C158 ◽  
Author(s):  
E. Page
Keyword(s):  
Quantitative Analysis ◽  
Membrane Structure ◽  
Statistical Approach ◽  
Optical Diffraction ◽  
Intracellular Membrane ◽  
Quantitative Measurements ◽  
Yield Information ◽  
Morphometric Methods ◽  
Sampling Problems ◽  
Membrane Physiology

Quantitative measurements on electron micrographs of heart muscle can yield information useful for cellular physiologists and at present not obtainable in other ways. These methods are subject to preparative artifact, sampling problems, and problems inherent in the mathematical description of ultrastructure. Nevertheless they provide the best available data for membrane areas of the plasmalemma and its components, as well as for membrane areas of the sarcoplasmic reticulum and mitochondria. Morphometric methods can be used to study growth of membranes. Changes in the volumes of intracellular membrane-limited subcompartments can also be measured. Quantitative analysis of freeze-fractured membrane replicas can be carried out either by a statistical approach or by optical diffraction. In this way, physiological perturbations or developmental events leading to changes in membrane permeability can be studied for correlated changes in membrane structure.

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