scholarly journals Crustacea: The Increasing Economic Importance of Crustaceans to Humans

2021 ◽  
Author(s):  
Gregorius Nugroho Susanto
Keyword(s):  
Brackish Water ◽  
Economic Importance ◽  
Water Bodies ◽  
Hermit Crabs ◽  
Free Living ◽  
Economic Progress ◽  
Great Economic Importance ◽  
Terrestrial Environments

Crustaceans (subphylum Crustacea) are members of the phylum Arthropods, including crabs, lobsters, crayfish, prawn, shrimp, krill, barnacles, woodlice and beach fleas. The most common types of crustaceans are shrimp and crab. This subphylum is distinguished from other arthropods, including myriapods, insects, and chelicerates, by the presence of two-parted (biramous) appendages, and the hatchling’s nauplius shape. In addition, these arthropods are majorly aquatic, often found in fresh, marine, or brackish water bodies, however, some crabs, hermit crabs, woodlice and other members of the subphylum, are found in terrestrial environments. Also, most crustaceans are free-living while numerous are parasitic (for instance, Rhizocephala, tongue worms, fish lice) and sessile (barnacles). Mostly lived nocturnal. Crustaceans have a great economic importance to humans. The group is of great value directly or indirectly for his health and economic progress, such as aesthetic, commercial, gastronomic, biomedical, bioindicator, biomonitor, geological values, and miscellaneous uses, biodeterioration and poisons.

Schwingungsüberlagertes Axialformen/Superimposed Oscillated Axial Forming

2020 ◽  
Vol 110 (11-12) ◽  
pp. 838-843
Author(s):  
Philipp Müller ◽  
Bernd-Arno Behrens ◽  
Sven Hübner ◽  
Hendrik Vogt ◽  
Daniel Rosenbusch ◽  
...  
Keyword(s):  
Surface Quality ◽  
Economic Importance ◽  
Combined Effect ◽  
Wird Eine ◽  
Forming Force ◽  
Forming Process ◽  
Forming Technology ◽  
Great Economic Importance ◽  
Gear Geometry

Techniken zur Steigerung der Formgebungsgrenzen in der Umformtechnik sind von hoher wirtschaftlicher Bedeutung. In dieser Arbeit wird eine Schwingungsüberlagerung im Krafthauptfluss eines Axialformprozesses zur Ausprägung einer Verzahnungsgeometrie untersucht. Die Auswirkungen der Schwingung auf die erzielbare Ausfüllung der Zahnkavitäten werden analysiert sowie die Parameter Schmierung und Oberflächengüte der Halbzeuge in ihrer kombinierten Wirkung untersucht. Es konnte eine Reduzierung der mittleren Umformkraft sowie eine Erhöhung der Formfüllung festgestellt werden. Techniques for extending the production limits in forming technology are of great economic importance. In this research, a superimposed oscillation in the main force flow of an axial forming process to form an axial gear geometry is investigated. The effects of the superimposed oscillation on the achievable form-filling of the tooth cavities are analyzed and the parameters lubrication and surface quality of the semi-finished products are investigated in their combined effect. A reduction of the averaged forming force as well as an increase of the form-filling could be achieved.

scholarly journals Fishery regulamentation or ethnoknowledge? The dilemma of the management of the mapará fisheries on the lower Tocantins river in northern Brazil

2021 ◽  
Vol 10 (11) ◽  
pp. e131101118963
Author(s):  
Esther Mirian Cardoso ◽  
Paulo Allison Costa da Mata ◽  
Matheus dos Santos Souza ◽  
Maria Clara Pinheiro de Souza ◽  
Victoria Isaac
Keyword(s):  
Socioeconomic Development ◽  
Economic Importance ◽  
Chi Square ◽  
Great Economic Importance ◽  
Chi Square Test ◽  
Northern Brazil ◽  
The Mean ◽  
Tocantins River ◽  
Student’S T ◽  
Student’S T Test

The fishery of mapará (Hypophthalmus marginatus) is of great economic importance in the Amazon region. Despite this, it is observed that the current norms of management disagree with the ethnoknowledge of fishermen of the Tocantins river. Therefore, there are many seizures and fines in the Tocantins Low region. This work appeared as a demand of the fishermen of the region and had as purpose to test the pertinence of the fishing legislation on the capture of the species and to provide subsidies for the adaptation of the norms to the local reality. For this, a mapará fishery was taken on the Pindobal Grande river, in the municipality of Igarapé-Miri, in the state of Pará. A sample of the captured individuals was collected, and identification, sexing and biometry were done. Fishing was described, and the sex ratio tested with the Chi-Square test and the mean length differences between the sexes with the Student's t-test. The results were compared with current legislation and literature data. The captured mapará individuals were mostly above 30 cm, as determined by legislation. It is concluded that, despite using a network that is prohibited, the capture of the species in the region acts selectively, due to the ethno-cognition and the fisherman's action ("taleiro"). Therefore, it is necessary that the legislation be revised, seeking the reconciliation between the conservation of ecosystems, the traditional knowledge and the socioeconomic development of the region.

scholarly journals Species Composition Features of Zoopankton in Mineralized Water Bodies from Specially Protected Natural Territories in Ulug-Khem Basin (Republic of Tuva)

2021 ◽  
pp. 398-414
Author(s):  
A. К. Kirova
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Brackish Water ◽  
Anthropogenic Impact ◽  
Water Bodies ◽  
Natural Objects ◽  
Mineralized Water ◽  
The Status ◽  
Favorable Conditions ◽  
Specially Protected Natural Territories

The species composition of zooplankton in mineralized water bodies located in the Ulug-Khem basin (Republic of Tuva) was studied. These lakes have the status of natural monuments of regional significance. In total we recorded 53 species of microscopic Custaceans and Rotifers from 32 genera, 13 families, and 8 orders. Cladocera comprises 53% of the species. The dependence of the species diversity on the level of mineralization was revealed; 89% of the species were found in brackish water bodies. The zooplankton composition of the hyperhaline lakes Dus-Khol (Svatikovo) and Cheder has remained constant for many dozen years. The zooplankton includes some species known only from Republic of Tuva in Russia, namely, Microcyclops afganicus and Macrotrix tabrizensis. M. asiaticus and Alona irinae, rare for the fauna of Russia, live in the lake Haak-Hol. A decrease in the total numbers of zooplankton is observed in the lakes, namely: in the lake Dus-Khol, it has decreased by 4 times, in the lake Khadyn it has decreased by 10–19 times as compared to the middle of the last century. Despite the lack of intermediate information, we regard this as a consequence of anthropogenic impact. The emergence of an indicator of pollution (Brachionus nilsoni) in the lake Khadin confirms this version. At the same time, the stable finding of species rare for the fauna of Russia indicates the presence of favorable conditions for their development and life, which increases the value of the reservoirs themselves, which are already unique natural objects.

Engineering Meteorology: The Weathering of Exposed Surfaces by Atmospheric Pollution 1

1959 ◽  
Vol 40 (4) ◽  
pp. 172-178
Author(s):  
R. E. Munn
Keyword(s):  
Air Pollution ◽  
Atmospheric Pollution ◽  
Industrial Area ◽  
Economic Importance ◽  
Economic Costs ◽  
Community Surveys ◽  
Corrosion Tests ◽  
Great Economic Importance ◽  
Dry Climates ◽  
And Control

The topic is approached from the viewpoint of community air-pollution programs and control. After a brief discussion of the economic costs of atmospheric pollution in an industrial area, a skeleton outline of the important factors in weathering by pollutants is presented. A few of the factors are considered in detail under the general headings of soiling, erosion, and corrosion. Significant differences in weathering are found for industrial, rural, marine, and very dry climates. Most community surveys include routine tests of the dirtiness of the air but exclude corrosion tests, although this factor is of great economic importance. Methods of corrosion testing are considered, and it is concluded that they are not feasible yet for community surveys. Increasing interest in corrosion, however, is undoubtedly leading to a broader understanding of the problem.

Effect of Environmental Variables on Zooplankton Assemblages in Two Brackish Water Bodies

2019 ◽  
Vol 45 (3) ◽  
pp. 236-251
Author(s):  
A. Gutkowska ◽  
E. Paturej ◽  
J. Koszałka
Keyword(s):  
Brackish Water ◽  
Environmental Variables ◽  
Water Bodies

The Importance of Liming Acid Soils of the Sahel Regions of Africa to Sustain High Crop Productivity—a Case Study from the Republic of Cameroon

1992 ◽  
Vol 28 (4) ◽  
pp. 473-476 ◽  
Author(s):  
K. P. Prabhakaran Nair ◽  
V. Ngachie ◽  
F. Nzetchoung
Keyword(s):  
Arachis Hypogaea ◽  
Acid Soils ◽  
Crop Productivity ◽  
Economic Importance ◽  
Great Economic Importance ◽  
Pot Experiments ◽  
The Republic ◽  
Limed Soil

SUMMARYGroundnut (Arachis hypogaea) has very great economic importance in Cameroon. In pot experiments, groundnut yields on highly acidified but limed soil were 50% greater than those on unlimed soil. These results demonstrate that severely acidified soils of the western highlands of Cameroon should be limed at moderate rates to sustain crop productivity.

Nutrients excretion by zooplankton in two brackish water bodies

2018 ◽  
Vol 103 (1-2) ◽  
pp. 15-25
Author(s):  
Agnieszka Gutkowska ◽  
Ewa Paturej ◽  
Magdalena Bowszys
Keyword(s):  
Brackish Water ◽  
Water Bodies

II.—The Unconformable Relationship of the Lower Tertiaries and Upper Cretaceous of New Zealand

1911 ◽  
Vol 8 (12) ◽  
pp. 539-549 ◽  
Author(s):  
James Park
Keyword(s):  
New Zealand ◽  
Upper Cretaceous ◽  
Economic Importance ◽  
Lower Tertiary ◽  
Great Economic Importance ◽  
The Subject ◽  
Academic Discussion ◽  
Relationship Of

With the question of conformity or unconformity between the Lower Tertiary and Upper Cretaceous, there is associated a problem of great economic importance to New Zealand. The subject involves something more than a mere academic discussion. If conformity exists, then we have only one coal-bearing formation; but if unconformity, then we have two. I believe that both the stratigraphical and palæontological evidence is overwhelmingly in favour of the latter.

scholarly journals A highly active karstic aquifer bounded by saline waters: The Judea Group aquifer

2019 ◽  
Vol 98 ◽  
pp. 07008
Author(s):  
Ittai Gavrieli ◽  
Joseph Guttman ◽  
Yoseph Yechieli ◽  
Firas Talhami ◽  
Avihu Burg
Keyword(s):  
Brackish Water ◽  
Water Bodies ◽  
Karstic Aquifer ◽  
Mountain Ridge ◽  
Highly Active ◽  
Saline Waters ◽  
Spring System ◽  
East And West ◽  
Groundwater Basins ◽  
End Members

The freshwater of the Judea Group aquifer that recharges on the crest of the Judea and Samria Mountain ridge flows east and west, defining two groundwater basins. At the foothills of both basins the freshwater encounters ancient saline or brackish water. The mode of interaction between the two water bodies within each basin is different, although both eventually discharge as brackish spring system. We describe these systems and identify the source of the higher salinity end members.

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