scholarly journals Influence of physical and chemical factors on settlement and recruitment of the hydroid Tubularia larynx

1996 ◽  
Vol 140 ◽  
pp. 123-139 ◽  
Author(s):  
P Nellis ◽  
E Bourget
Keyword(s):  
Chemical Factors ◽  
Physical And Chemical

Further Studies upon Chemical Factors Affecting the Breeding of Anopheles in Trinidad

1934 ◽  
Vol 25 (4) ◽  
pp. 491-494 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Analytical Study ◽  
Chemical Constituents ◽  
Physical Factors ◽  
Factors Affecting ◽  
Early Stages ◽  
Freshwater Biology ◽  
Chemical Technique ◽  
Chemical Factors ◽  
Physical And Chemical

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

Menadione nicotinamide bisulphite as a source of vitamin K and niacin activities for the growing pig

2000 ◽  
Vol 71 (1) ◽  
pp. 111-117 ◽  
Author(s):  
M. Marchetti ◽  
M. Tassinari ◽  
S. Marchetti
Keyword(s):  
Vitamin K ◽  
Control Diet ◽  
Live Weight ◽  
Organic Salt ◽  
Free Form ◽  
Food Supplementation ◽  
Sodium Bisulphite ◽  
Chemical Factors ◽  
And Control ◽  
Physical And Chemical

AbstractWhen compared with other menadione derivatives such as menadione sodium bisulphite (MSB), menadione nicotinamide bisulphite (MNB), an organic salt combining menadione and nicotinamide, shows better stability towards physical and chemical factors once it is added to pre-mixes or foods. The present work evaluates the bioavailability of the two vitamins present in this compound and toxicity in the pig. To assess vitamin bioavailability, pigs were given small amounts of food containing MNB or equivalent amounts of MSB and nicotinamide in the free form. Menadione and nicotinamide concentrations in blood samples drawn at set times after the diets were given did not reveal any significant differences between the two modes of administration. Haematic levels of both vitamins in animals receiving MNB, or MSB and nicotinamide, were after 2, 4, 8 and 12 h higher (P < 0·001) than those of untreated animals. The tolerance level to MNB was evaluated in pigs given diets containing graded amounts of MNB (100, 500, 2500 mg/kg) for 28 days. No significant (P > 0·05) differences were recorded in live weight, food intake and gain/food ratio in pigs given these diets when compared with those given an unsupplemented diet. Haemoglobin and bilirubin levels did not differ between animals given various amounts of MNB and control animals. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in pigs given 100 mg/kg of MNB did not show significant differences when compared with those observed in pigs given an unsupplemented control diet. In pigs on the diets supplemented with 500 and 2500 mg/kg of MNB there was a significant increase in the two enzymatic activities as compared with controls (P < 0·001 and P < 0·01). In the case of ALT this had disappeared by 28 weeks. MNB is a good source of vitamin K for the pig and does not appear to have any adverse effects, even when administered at levels higher than those normally used in pig food supplementation.

The Qualitative and Quantitative Distribution of Plankton in the Strait of Georgia in Relation to Certain Oceanographic Factors

1957 ◽  
Vol 14 (4) ◽  
pp. 521-552 ◽  
Author(s):  
Joseph Eugène Henri Légaré
Keyword(s):  
Salinity Gradient ◽  
General Distribution ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Quantitative Distribution ◽  
Qualitative And Quantitative ◽  
Chemical Factors ◽  
Physical And Chemical ◽  
Plankton Communities ◽  
Made In

In order to gain some picture of the seasonal variations in the plankton communities two cruises were made in the Strait of Georgia, one in June 1955, and the other in November 1955; 165 plankton collections were taken, also surface temperatures.The correlation of these data have resulted in a number of conclusions concerning the distribution of plankton in the Strait of Georgia. The chief factor affecting the general distribution of plankton is the salinity gradient. The inflow of fresh water from the Fraser River forms zones of varying properties, and leads to the development of different plankton communities. The extent to which physical and chemical factors may determine the presence or absence of certain organisms from the zones described is discussed.

scholarly journals Short Communication: Community of phytoplankton in peatland canal, Riau, and wet dune slacks of Parangtritis, Yogyakarta, Indonesia

2020 ◽  
Vol 21 (5) ◽  
Author(s):  
Annisa Mawarni ◽  
Firda Nabila Nur Azizah ◽  
Heni Wahyu Sartika ◽  
Suwarno Hadisusanto ◽  
Dwinda Mariska Putri ◽  
...  
Keyword(s):  
Phytoplankton Community ◽  
Short Communication ◽  
Phosphate Concentration ◽  
Water Sampler ◽  
Dune Slacks ◽  
Chemical Factors ◽  
Synedra Acus ◽  
Physical And Chemical ◽  
Temperature Water ◽  
Special Region

Abstract. Mawarni A, Azizah FNN, Sartika HW, Hadisusanto S, Putri DM, Reza A. 2020. Short Communication: Community of Phytoplankton in peatland canal, Riau, and wet dune slacks of Parangtritis, Yogyakarta, Indonesia. Biodiversitas 21: 1874-1879. The ecosystems of peatland canal and wet dune slacks have specific characteristics for phytoplankton community. This study aimed to elaborate on the distribution and abundance of phytoplankton community in peatland canal of Sungai Tohor Village, Meranti Islands, Riau and wet dune slacks of Parangtritis, Special Region of Yogyakarta. Phytoplankton was collected using a 2-L modified Van Dorn water sampler. In peatland, canal phytoplankton was sampled at 3 different locations, each with 5 repetitions. Meanwhile, in wet dune slacks, phytoplankton was sampled at 5 locations, each with 3 repetitions. Phytoplankton samples were filtered with Wisconsin plankton-net 120 mesh and fixed with 3 drops of formaldehyde 4%. The measured physical and chemical factors were air temperature, water temperature, dissolved oxygen, alkalinity, carbon dioxide, pH, depth, transparency, nitrate, sulfate, and phosphate concentration. The results showed that the distribution and abundance of phytoplankton community in wet dune slacks were greater than those of the peatland community. This research found 18 species of phytoplankton in peatland canal, dominated by Synedra acus and 116 species of phytoplankton in wet dune slacks, dominated by Cyclotella meneghiniana. 

scholarly journals On the Advanced Technique of Mathematical and Computer Simulation of Filtration Processes in Porous Media under the Influence of Physical and Chemical Factors

2019 ◽  
pp. 33-34
Author(s):  
Volodymyr Gerus
Keyword(s):  
Computer Simulation ◽  
Porous Medium ◽  
Porous Media ◽  
Advanced Technique ◽  
Variable Porosity ◽  
Continuity Equations ◽  
Mathematical And Computer Simulation ◽  
Chemical Factors ◽  
Physical And Chemical

The proposed improvement of the technique for deriving filtration equations in soils with variable porosity is described. The technique is based on the application of the apparatus of complete derivatives in the soil phase continuity equations. Examples of filtration equations in the case of a deformable and non-deformable skeleton of a porous medium are given.

Sign in / Sign up

Export Citation Format

Share Document