Search results for "CATCHER"

Cryogenic helium as stopping medium for high-energy ions

2008

We have investigated the survival and transport efficiency of Ra-219 ions emitted by a Ra-223 source in high-density cryogenic helium gas, with ionisation of the gas induced by a proton beam. The combined efficiency of ion survival and transport by an applied electric field was measured as a function of ionisation rate density for electric fields up to 160 V/cm and for three temperature and density combinations: 77 K, 0.18 mg/cm(3), 10 K, 0.18 mg/cm(3) and 10 K, 0.54 mg/cm(3). At low beam intensity or high electric field, an efficiency of 30%, is obtained, confirming earlier results. A sharp drop in efficiency is observed at a "threshold" ionisation rate density which increases with the squ…

Polyterritorial Polygyny in the Pied Flycatcher

1990

Publisher Summary The chapter discusses on the evolution of polyterritoriality in Ficedulu hypofeuca species. It estimates the costs and benefits to males and females, and uses the results to evaluate current alternative polygyny models. This chapter also explains that secondary females raise fewer offspring that most likely are of poorer quality than offspring of monogamous and primary females. This is probably not because the secondary females are of lower quality than other females settling at the same time, but because one could not find any differences in age or morphology of simultaneously mated monogamous and secondary females. The main reason is that offspring raised by polygynously…

The design of artificial nestboxes for the study of secondary hole-nesting birds: A review of methodological inconsistencies and potential biases

2010

The widespread use of artificial nestboxes has led to significant advances in our knowledge of the ecology, behaviour and physiology of cavity nesting birds, especially small passerines. Nestboxes have made it easier to perform routine monitoring and experimental manipulation of eggs or nestlings, and also repeatedly to capture, identify and manipulate the parents. However, when comparing results across study sites the use of nestboxes may also introduce a potentially significant confounding variable in the form of differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained. However, the use of …

Teknologia ja huolen eleet elokuvassa Rotanpyydystäjä

2023

Male coloration and species recognition in sympatric flycatchers

1994

Currently favoured views for explaining ornaments in males emphasize female preference such that females benefit from increased offspring production, good genes of the offspring, or the attractiveness of sons. Results from long-term studies in the pied flycatcher Ficedula hypoleuca suggest that factors associated with species recognition may also be important for male coloration. In sympatry the collared flycatcher F. albicollis is dominant in competition for nesting sites over the pied flycatcher. Bright pied flycatcher males resemble collared flycatcher males and suffer from interspecific interference, whereas dull and female-like males can acquire nesting sites close to those of the coll…

Heterospecific female mimicry in Ficedula flycatchers

2014

Mimicry is a widespread phenomenon. Vertebrate visual mimicry often operates in an intraspecific sexual context, with some males resembling conspecific females. Pied flycatcher (Ficedula hypoleuca) dorsal plumage varies from the ancestral black to female-like brown. Experimental studies have shown that conspecific and heterospecific (collared flycatcher, F. albicollis) individuals of both sexes respond, at least initially, to brown individuals as if they were female. We quantified the perceptual and biochemical differences between brown feathers and found that brown pied flycatcher males are indistinguishable from heterospecific, but not from conspecific, females in both aspects. To our kno…

NOTE SUI LIMICOLI SVERNANTI NELLE ZONE UMIDE COSTIERE DELLA PROVINCIA DI TRAPANI

2016

Notes on wintering waders in the coastal humid zones of province of Trapani (Sicily). The coastal wetlands of Trapani still are of great national importance for migratory and wintering waders despite the dramatic reduction occurred in the last hundred years. During this research the author carried out surveys in coastal wetlands from Trapani to Mazara del Vallo, in order to estimate qualitative and accurate quantitative values of wintering waders. The census includes four winters, from 2012-13 to 2015-16 and was carried out in the months of December and January. Noteworthy is the wintering for three consecutive years of the Terek Sandpiper Xenus cinereus, the wintering of Oystercatcher Haem…

Patterns of variation in tail ornament size in birds

1988

In recent years several different kinds of sexual selection models have been developed, and tail ornaments in birds have frequently been used as an example of a sexually selected character where the models might apply. However, very little is known about intra- and interpopulation variation in ornament size. We have studied the elongated tail ornaments in four species of whydahs Vidua, the forktailed flycatcher Tyrannus savana and the Asian paradise flycatcher Terpsiphone paradisi. Ornaments were relatively longer in males with the longest tarsi (‘heterogony’ with positive allometry). Also, tail lengths were remarkably variable within each geographical area, the coefficient of variation (av…

Reduction of nitrate leaching: what is the contribution of the residual weed flora?

2018

International audience; Integrated crop protection tolerates residual weeds if they are not harmful for crop production. Weeds are often solely considered as a pest, causing crop yield loss, harvest pollution, diseases … However, they may also provide beneficial services for agroecosystems, promoting plant biodiversity and feeding other organisms potentially beneficial to crop production (pollinators, carabids…). The role of residual weed flora as nitrate catchers, during summer fallow, has however rarely been assessed. Yet, some weed species are known for their high potential to take up soil nitrogen. The present study aimed to (1) develop an indicator to account for the potential benefici…

Passive sampling in monitoring of nonylphenol ethoxylates and nonylphenol in aquatic environments

2012

The present practices for determining the concentration levels of various pollutants are in many respects insufficient and for this reason, there is an urgent need especially to develop more cost-effective sampling methods. In this study, a novel passive sampling tool (the Chemcatcher®) for monitoring nonylphenol ethoxylates (NPEOs) and nonylphenol (NP) in aqueous media was tested. These environmentally harmful substances have been widely used in different household and industrial applications and they affect aquatic ecosystems, for example, by acting as endocrine disrupting compounds. The highest accumulation of NPEOs and NP in laboratory-scale tests was obtained when using an SDB-XC (stan…