Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 7
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The red-banded stink bug, Piezodorus guildinii, is an important pest in soybean. Information on its distribution is needed to determine the most effective timing for pest control and strategies to avoid yield losses, such as adequate monitoring. The present study was aimed at examining the temporal variation and spatial distribution of P. guildinii in soybean. The experimental design comprised an area of 5400 m² planted with soybean, with 54 plots of 100 m² each, in which plants were examined weekly for nymphs and adults of P. guildinii with a beating sheet. Evaluations were carried out from soybean emergence to harvest; however, P. guildinii occurred only during the reproductive stage. Based on aggregation indices, theoretical frequency distributions, and semivariograms, nymphs and adults were randomly distributed at the beginning of infestation but, tended to be aggregate during pod setting and seed filling. Our findings have a contribution to improving pest sampling systems and infestation mapping, including future semiochemicals studies.
Go to article

Authors and Affiliations

Rafael Azevedo Silva
1
Paulo Eduardo Degrande
2
ORCID: ORCID
Bruno Souza Martins
1
ORCID: ORCID
Ellen Patricia Souza
2
ORCID: ORCID
Marcos Gino Fernandes
2
ORCID: ORCID

  1. Department of Plant Protection, Federal Institute of Mato Grosso do Sul, Brazil
  2. Department of Agricultural Science, Federal University of Grande Dourados, Dourados, Brazil
Download PDF Download RIS Download Bibtex

Abstract

The present study aims at evaluating the quality of shallow groundwater (SGW) and its suitability for irrigation purpose in the most urbanised part of Johannesburg city, South Africa. The SGW samples were collected in three consecutive years and analysed for 20 selected physicochemical parameters, and heavy metals. The results were compared with the South African water quality, and Food and Agricultural Organization irrigation water quality guidelines, and standard indices derived from laboratory outputs. The results of the study show that all physiochemical parameters and heavy metals were within the limits set by both guidelines for irrigation purposes, except for potassium (3.58 mg∙dm –3) and manganese levels (3.152 mg∙dm –3). The calculated irrigation parameter values of sodium adsorption ratio ( SAR), sodium percentage (Na%), residual sodium carbonate ( RSC), magnesium hazard ( MH), Kelly’s ratio ( KR) and permeability index ( PI) were within the permissible range of irrigation water quality standards. The findings of this study provide helpful information for decision-makers such as utilisation of the studied groundwater for irrigation uses.
Go to article

Authors and Affiliations

Simeneh S. Moges
1
ORCID: ORCID
Megersa O. Dinka
1
ORCID: ORCID

  1. University of Johannesburg, Department of Civil Engineering Science, PO Box 524, Auckland Park, 2006, Johannesburg, South Africa
Download PDF Download RIS Download Bibtex

Abstract

Heartbeat and respiration of southern elephant seals (Mirounga leonina), Weddell seals (Leptonychotes weddellii) and Antarctic fur seals (Arctocephalus gazella) were monitored simultaneously using a visual and non-intrusive method, at King George Island, South Shetland Islands. All three species demonstrated sleep apnoea with reduced heart rate. In adult elephant seals, heartbeat fell 18% in apnoea; spells lasted up to nine min, usually ending in disturbance from conspecifics or human visitors. Slight human disturbance (notably slight noise) reduced time spent in apnoea from over 40% to 4%, significantly reducing the frequency of falling into apnoea and increasing mean heartbeat. Further disturbance resulted in head raising, aggression, scratching, rolling and movement away. The visual monitoring of heartbeat and respiration can be used with resting or slightly disturbed animals but not when major body movements occur.

Go to article

Authors and Affiliations

Katarzyna Salwicka
Bernard Stonehouse
Download PDF Download RIS Download Bibtex

Abstract

In 1979- 1981 at the King George Island samples of adipose tissue of 5 pinniped species (L. carcinophagus, L. weddelli, H. leptonyx, M. leonina and A. gazella) were collected and the contents of chlorinated hydrocarbons (CHs) were determined with the gas chromatography method. The highest values were recorded in the leopard seal (432.3 -614.7 ppb DDT), the second highest values in the mature elephant seal (73.4 ppb DDT) and the third in the Weddell seal (54.4 — 69.1 ppb DDT). In the Weddell seal the highest level of HCH content (23.3 — 32.1 ppb) was recorded. A decrease in the content of pp'DDE in the adipose tissue of crabeater seal in successive years was recorded, the values being 36.8 ppb in 1979, 24.4 ppb in 1980 and 15.3 ppb in 1981, as well as an increase in the concentration of HCH (15.3 ppb in 1980 and 27.4 ppb in 1981). The contents of CHs in the adipose tissue of Antarctic pinnipeds are 100—1000 times lower than those in the Arctic seals.

Go to article

Authors and Affiliations

Marek A. Karolewski
Aleksy B. Łukowski
Ryszard Halba
Download PDF Download RIS Download Bibtex

Abstract

The present paper addresses the analysis of structural vibration transmission in the presence of structural joints. The problem is tackled from a numerical point of view, analyzing some scenarios by using finite element models. The numerical results obtained making use of this process are then compared with those evaluated using the EN 12354 standard vibration reduction index concept. It is shown that, even for the simplest cases, the behavior of a structural joint is complex and evidences the frequency dependence. Comparison with results obtained by empirical formulas reveals that those of the standards cannot accurately reproduce the expected behavior, and thus indicate that alternative complementary calculation procedures are required. A simple methodology to estimate the difference between numerical and standard predictions is here proposed allowing the calculation of an adaptation term that makes both approaches converge. This term was found to be solution-dependent, and thus should be evaluated for each structure.

Go to article

Authors and Affiliations

Jaime Ramis
Enrique Segovia
Jesús Alba
Jesús Carbajo
Luís Godinho
Download PDF Download RIS Download Bibtex

Abstract

The early philosophical standpoint of Professor Bogusław Wolniewicz alluded mainly to the so-called first philosophy of Ludwig Wittgenstein, as expressed in his Tractatus Logico-Philosophicus. Professor Wolniewicz’s views have found their expressions, first, in the book (in Polish) Things and Facts. An introduction to the first philosophy of Ludwig Wittgenstein (1968), and finally in his monograph (in Polish) Ontology of Situations. Foundations and Applications (1985). In both cases, Wolniewicz’ standpoint has been expressed by giving a substantive interpretation to semiotical and logical concepts (i.e. by producing hypostases). This practice looks rather dubious to me, in both cases, although I hope that ontology of situations can be usefully treated as a general formal theory of semantical correlates characteristic for sentential statements.

Go to article

Authors and Affiliations

Józef Andrzej Stuchliński
Download PDF Download RIS Download Bibtex

Abstract

The author highly appreciates the fi rst issue of the third volume of the fundamental “Dictionary of folk stereotypes and symbols” (ed. prof. E. Bartminsky), dedicated to the symbolism of plants. This issue presents rich materials (language, folklore, ethnographic) related to cereals, which in the popular perception have a mythological interpretation, the daily bread is God’s gift, endowed with sacred significance.

Go to article

Authors and Affiliations

Светлана М. Толстая
ORCID: ORCID

This page uses 'cookies'. Learn more