Search results for "Fish"

Testing steady-state analysis of single-ring and square pressure infiltrometer data

2016

Testing reliability of the saturated soil hydraulic conductivity, Ks, estimated by applying the steady-state single-ring (SR) model to the quasi steady-state infiltration rates obtained with a single-ring pressure infiltrometer (PI) increases confidence in the estimated Ks values. Determining a means to estimate Ks from infiltration data collected with a square infiltrometer allows the use of sources of different shapes. Using numerically simulated infiltration rates for six homogeneous soils ranging in texture from sand to silty clay loam, this investigation suggested an overall good performance of the SR model, with estimated Ks values differing by not more than 25% from the true values f…

Effect of epidermal papillomatosis on survival of the freshwater fish Rutilus rutilus.

2004

Epidermal papillomatosis occurs in several marine and freshwater fish species. Previously, papillomatosis has been shown to induce mortality in juvenile carp. We studied the effect of epidermal papillomatosis on the survival of adult male roach Rutilus rutilus by caging naturally diseased, marked (by us) fish in the field. Within the constraints of the experimental design, there was no difference in survival between healthy, slightly diseased and heavily diseased fish. Therefore, we conclude that the possible effect of epidermal papillomatosis on the mortality of wild roach is relatively minor.

Advances in designing drip irrigation laterals

2018

It is known that using paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency (WUE). Recently, an analytical procedure to optimally design paired drip laterals on uniform slopes was proposed. More recently, this design procedure was simplified by deriving simple explicit relationships, as a function of 16 calibration constants, with relative errors that were less than 2%. In this paper, further simple design relationships are derived that require only 3 calibration constants, thus more readily obtainable results are produced and the influence of the flow rate and diameter exponents of resistance eq…

Protective effect against mycotoxin occurrence of different additives in smoked fish

2015

Being successful in the world of narrow opportunities: transmission patterns of the trematode Ichthyocotylurus pileatus.

2009

SUMMARYParasites with complex life cycles face 2 major challenges for transmission in northern latitudes. They have to cope with the general unpredictability associated with the series of transmission events required for completion of the cycle, and transmission has to be completed within a narrow temporal window because of strong seasonality. Despite this, some parasites show high transmission success, suggesting the operation of effective transmission mechanisms. We explored the transmission of Ichthyocotylurus pileatus (Trematoda) from its snail (Valvata macrostoma) to fish (Perca fluviatilis) hosts by examining some key characteristics in the dynamics of the cercarial emergence from sna…

The Beginning and End of Parental Responsibility — Finnish Parents’ Views

2012

INTRODUCTIONParental responsibility is a topic much discussed in present-day society. In these discussions the concept of parental responsibility appears self-explanatory, and it is often seen as the common denominator in dealing with child behaviour and educational issues, particularly in problem-centred discussions. Generally, responsibility seems to be one of the key concepts in policy-making and public debate about the lives of children and parents (Such & Walker, 2004).A theoretical model of present-day life that deals with parenting but also relates to parental responsibility is the theory of individualization (Giddens 1991, 1992). Individualization is a term used by Beck and Beck-Ger…

Plant diversity enhances the natural attenuation of polycyclic aromatic compounds (PAHs and oxygenated PAHs) in grassland soils

2019

Increasing plant species richness stimulates microbial activity in soil, which might favor biodegradation of polycyclic aromatic compounds (PACs). To explore the relationship between plant community composition and PACs in grassland soils (Fluvisols exposed to an urban atmosphere), we determined the concentrations of 29 polycyclic aromatic hydrocarbons (PAHs) and 15 oxygenated PAHs (OPAHs) in topsoils of 80 plots of a grassland biodiversity experiment. The plots included different levels of plant species richness (1, 2, 4, 8, 16, 60 species) and 1–4 plant functional groups (grasses, small herbs, tall herbs, and legumes) in a randomized block design. The concentrations (ng g−1) of ∑29PAHs an…

Long-term effects of contrasting tillage systems on soil C and N pools and on main microbial groups differ by crop sequence

2021

Abstract Determining the best conservation agriculture practices for increasing soil organic carbon (C) and hence soil quality is of paramount importance in the semi-arid Mediterranean environment, where soils are experiencing a continuous decline in organic matter. Therefore, the aim of this long-term study was to assess the combined effects of tillage system and crop sequence on soil organic C and biochemical properties of soil generally used as indicators of soil quality. After 23 years of continuous application of contrasting tillage systems (conventional tillage [CT], vs. no tillage [NT]) and crop sequences (wheat monoculture vs. wheat-faba bean rotation), soil samples were collected f…

An extra-urban soil cadastre for Italy: a first guide for the introduction of soil information

2020

Assuming a positive outcome of the parliamentary procedure for laws and, thus, the transformation of the official cadastre for buildings and land into a soil cadastre (urban, extra-urban and cadastre for the conservation of natural or semi-natural soil diversity) would start a new era for pedology. Finally, after many decades of activity to expand soil culture in Italy, almost all Italian families would be in contact with a soil specialist. Land use and redefined plots would be handled with greater care and responsibility. Experts in agricultural and forestry and biodiversity conservation would have a new impetus in their activity. Furthermore, economists will also have to address new issue…

Soil profile dismantlement by land levelling and deep tillage damages soil functioning but not quality

2016

We investigated the effects of land levelling followed by deep tillage, thus inducing a drastic dismantlement of soil profile, on both soil functioning and quality by monitoring various bioindicators (microbial biomass and community structure, basal respiration, enzyme activities) expressed on either whole soil and TOC mass units, respectively. As expected, in disturbed soils all measured properties had much higher coefficients of variation (CVs), regardless of either whole soil or TOC mass basis, due to the induced spatial variability. The amount of total organic C in the first cubic meter of soil profile was of one order of magnitude greater in undisturbed soils compared to disturbed ones…