Search results for "Chin"

Organic nitrogen steadily increasing in Norwegian rivers draining to the Skagerrak coast

2020

AbstractDeclining atmospheric nitrogen (N) deposition, through reduction in the direct input of inorganic N, may result in less inorganic N being leached from soils to freshwaters (dissolved inorganic N = DIN). Declining sulphur deposition, through reducing the ionic strength in soil water, increases the solubility and mobility of organic soil compounds and may result in increased leaching of organically bound N to freshwaters (total organic N = TON). It is unknown to which extent these two independents and opposing trends, i.e. DIN decline versus TON increase, may affect the nutrient balance (load, stoichiometry) of river water draining into coastal zones. By combining long-term atmospheri…

Automatic measurement of wood fiber orientation and knot detection using an optical system based on heating conduction.

2015

In this paper, a new approach to computing the deviation of wood grain is proposed. To do this, the thermal conduction properties of timber are used (higher conduction in the fiber direction). Exciting the surface of the wood with a laser and capturing the thermal conduction using a thermal camera, an ellipse can be observed. Using a method similar to the tracheid effect, it is possible to extract information from this ellipse, such as the slope of grain and the presence of knots. With this method it is therefore possible to extend the mechanical model (assessing the mechanical properties of timber) to take certain singularities into account. Using this approach, the slope of grain can be e…

2016

Several neotropical orchid genera have been proposed as being sexually deceptive; however, this has been carefully tested in only a few cases. The genus Telipogon has long been assumed to be pollinated by male tachinid flies during pseudocopulatory events but no detailed confirmatory reports are available. Here, we have used an array of methods to elucidate the pollination mechanism in Telipogon peruvianus. The species presents flowers that have a mean floral longevity of 33 days and that are self-compatible, although spontaneous self-pollination does not occur. The flowers attract males of four tachinid species but only the males of an undescribed Eudejeania (Eudejeania aff. browni; Tachin…

The role of partial incubation and egg repositioning within the clutch in hatching asynchrony and subsequent effects on breeding success

2019

The main mechanism to achieve hatching asynchrony (HA) for incubating birds is to start heating the eggs before clutch completion. This might be achieved through partial incubation and/or early incubation. Even in the absence of incubation behaviour during the laying phase, clutches still experience a certain degree of asynchrony. Recent studies have shown that eggs located in the centre of the nest receive more heat than peripheral ones during incubation. As eggs receiving more heat would develop faster, we hypothesized that HA should be shorter in nests where eggs were moved homogeneously along the centre–periphery space during incubation than in those nests where eggs repeatedly remained…

Effects of ocean acidification on embryonic respiration and development of a temperate wrasse living along a natural CO2gradient

2016

We assessed rising CO2 effects on metabolism and development of a nesting wrasse by reciprocal transplant experiments in the field. Offspring brooded under different CO2 conditions exhibited similar responses. However, embryos from High-CO2 site were resilient to a wider range of pCO2 levels than those belonging to current-day conditions.

Underwater high frequency noise: Biological responses in sea urchin Arbacia lixula (Linnaeus, 1758)

2020

Marine life is extremely sensitive to the effects of environmental noise due to its reliance on underwater sounds for basic life functions, such as searching for food and mating. However, the effects on invertebrate species are not yet fully understood. The aim of this study was to determine the biochemical responses of Arbacia lixula exposed to high-frequency noise. Protein concentration, enzyme activity (esterase, phosphatase and peroxidase) and cytotoxicity in coelomic fluid were compared in individuals exposed for three hours to consecutive linear sweeps of 100 to 200 kHz lasting 1 s, and control specimens. Sound pressure levels ranged between 145 and 160 dB re 1μPa. Coelomic fluid was …

Cercospora beticola Toxin Inhibits Vanadate-Sensitive H+ Transport in Corn Root Membrane Vesicles

1988

The effect of Cercospora beticola toxin on the transport of protons by vanadate-sensitive ATPase was studied with corn (Zea mays) root microsomal vesicles prepared by differential centrifugation, sedimentation through a sucrose cushion, and washing with Triton X-100 plus KBr. In these preparations, addition of ATP induced intravesicular H(+)-accumulation as evidenced by a rapid quenching of the fluorescence of 9-amino-6-chloro-2-methoxy acridine. This quenching was relatively unaffected by inhibitors of mitochondrial and tonoplast-type ATPases, but was strongly reduced by inhibitors of plasma membrane H(+)-ATPase. C. beticola toxin markedly inhibited ATP dependent H(+)-transport, and this e…

Spatial distribution, contamination assessment and potential ecological risk of some trace metals in the surface sediments of the Gulf of Tunis, Nort…

2021

To evaluate the trace metals contamination status in the Gulf of Tunis, forty one sediment samples were analyzed using different approaches. According to certain contamination and ecological risk indices (Contamination Factor, Geoaccumulation index and Ecological risk index), Hg has the highest contamination level while pollution by Ni, Pb, Cd and Cr was absent. The highest concentrations of trace metals were found in sediments collected from the offshore and coastal areas located opposite the main exchange points with the gulf particularly, the Mejerda and Meliane Rivers, the Khalij Channel, Ghar El Melh and El Malah lagoons, Tunis Lake and Sebkhat Ariana. However, further ecological indic…

A recipe for postfledging survival in great tits Parus major: be large and be early (but not too much)

2016

Survival of juveniles during the postfledging period can be markedly low, which may have major consequences on avian population dynamics. Knowing which factors operating during the nesting phase affect postfledging survival is crucial to understand avian breeding strategies. We aimed to obtain a robust set of predictors of postfledging local survival using the great tit (Parus major) as a model species. We used mark–recapture models to analyze the effect of hatching date, temperatures experienced during the nestling period, fledging size and body mass on first-year postfledging survival probability of great tit juveniles. We used data from 5192 nestlings of first clutches ringed between 199…

Characterization of eight microsatellite loci for the sea urchin Meoma ventricosa (Spatangoida, Brissidae) through Next Generation Sequencing.

2015

Eight microsatellite loci were characterized for Meoma ventricosa (Lamarck, 1816), a burrowing sea urchin that can be afflicted by a bacterial disease causing localized mass mortality. For the analyzed population (29 individuals from St. Croix, US Virgin Islands), we observed 8.125 mean number of alleles, 0.640 mean observed heterozygosity (Ho) and 0.747 mean expected heterozygosity (He). Two loci showed significant deviations from Hardy-Weinberg equilibrium. Overall, the described loci were characterized by a moderately highlevel of polymorphism suggesting that these markers are useful for a population genetic studyin the Caribbean Sea.