645 research outputs found
Emotional and Adrenocortical Responses of Infants to the Strange Situation: The Differential Function of Emotional Expression
The aim of the study was to investigate biobehavioural organisation in infants with different qualities of attachment. Quality of attachment (security and disorganisation), emotional expression, and adrenocortical stress reactivity were investigated in a sample of 106 infants observed during Ainsworth’s Strange Situation at the age of 12 months. In addition, behavioural inhibition was assessed from maternal reports. As expected, securely attached infants did not show an adrenocortical response. Regarding the traditionally defined insecurely attached groups, adrenocortical activation during the strange situation was found for the ambivalent group, but not for the avoidant one. Previous ndings of increased adrenocortical activity in disorganised infants could not be replicated. In line with previous ndings, adrenocortical activation was most prominent in insecure infants with high behavioural inhibition indicating the function of a secure attachment relationship as a social buffer against less adaptive temperamental dispositions. Additional analyses indicated that adrenocortical reactivity and behavioural distress were not based on common activation processes. Biobehavioural associations within the different attachment groups suggest that biobehavioural processes in securely attached infants may be different from those in insecurely attached and disorganised groups. Whereas a coping model may be applied to describe the biobehavioural organisation of secure infants, an arousal model explanation may be more appropriate for the other groups
A competitive polymerase chain reaction-based approach for the identification and semiquantification of mitochondrial DNA in differently heat-treated bovine meat and bone meal
The risk of bovine spongiform encephalopathy propagation was drastically reduced after the European Union (EU) Health Authorities adopted restrictions involving a ban on animal-derived proteins in the diet of farm animals. Currently, the EU's officially recommended method for controlling meat and bone meal (MBM) in animal feed is the microscopic method, which involves the identification of bone fragments on the basis of their morphological characteristics. Recently, we demonstrated that a polymerase chain reaction (PCR)-based assay can be used for the detection of taxon-specific DNA in MBM and animal feeds. To ensure the safe rendering of animal by-products, the EU Council requires that this material be treated at 133degreesC at 300 kPa for 20 min. Here we investigate the relationship between DNA degradation, PCR amplification, and MBM heat treatment. With a competitive PCR-based approach, we compare the amplification efficiency of bovine mitochondrial DNA target sequences of different lengths in several heat-treated MBM samples. For our method, a synthetic competitive DNA is used as an internal control for both DNA extraction and PCR reaction. A correlation between an increase in treatment temperature and a reduction in the size of the target sequences suitable for amplification was observed, suggesting progressive DNA fragmentation due to the temperature. We show that short amplicons (147 bp) can be used to detect the presence of bovine mtDNA in MBM samples treated according to the current European regulations. The use of such a competitive approach to compare amplification efficiency levels of targets of different lengths might represent a useful tool for the determination of both the amount of MBM in animal feeds and its proper heat treatment
Poisson -- Boltzmann Brownian Dynamics of Charged Colloids in Suspension
We describe a method to simulate the dynamics of charged colloidal particles
suspended in a liquid containing dissociated ions and salt ions. Regimes of
prime current interest are those of large volume fraction of colloids, highly
charged particles and low salt concentrations. A description which is tractable
under these conditions is obtained by treating the small dissociated and salt
ions as continuous fields, while keeping the colloidal macroions as discrete
particles. For each spatial configuration of the macroions, the electrostatic
potential arising from all charges in the system is determined by solving the
nonlinear Poisson--Boltzmann equation. From the electrostatic potential, the
forces acting on the macroions are calculated and used in a Brownian dynamics
simulation to obtain the motion of the latter. The method is validated by
comparison to known results in a parameter regime where the effective
interaction between the macroions is of a pairwise Yukawa form
Standard and Light-Cycler PCR methods for animal DNA species detection in animal feedstuffs
In this work four species-specific primers and probes were designed and evaluated for the detection and quantification of bovine, ovine, swine and chicken mitochondrial DNA in feeds. PCR primers were optimized using conventional and Real Time PCR, to detect short species-specific sequences amplifiable from heat treated material. Both methods confirmed the high specificity of the primers designed. Real time quantitative PCR assay allowed the detection of as few as 0.01 ng and 0.05 ng of ovine and bovine genomic DNA, respectively. The detection limit for swine and chicken genomic DNA was 0.5 ng. Sensitivity levels observed in DNA extracted from meat samples processed according to EU legislation were different compared to those in genomic DNAs previously described. They resulted in swine 5 fg of MBM DNA, in chicken 25 ng, in ovine and bovine 50 ng. We confirmed the efficiency and specificity of primers in RT-PCR to detect 0.5% of bovine, ovine, swine and chicken MBM in contaminated feedstuffs. (C) 2007 Elsevier Ltd. All rights reserved
Tumor-associated Tenascin-C isoforms promote breast cancer cell invasion and growth by MMP-dependent and independent mechanisms
The sense of agency as tracking control
Does sense of agency (SoA) arise merely from action-outcome associations, or does an additional real-time process track each step along the chain? Tracking control predicts that deviant intermediate steps between action and outcome should reduce SoA. In two experiments, participants learned mappings between two finger actions and two tones. In later test blocks, actions triggered a robot hand moving either the same or a different finger, and also triggered tones, which were congruent or incongruent with the mapping. The perceived delay between actions and tones gave a proxy measure for SoA. Action-tone binding was stronger for congruent than incongruent tones, but only when the robot movement was also congruent. Congruent tones also had reduced N amplitudes, but again only when the robot movement was congruent.We suggest that SoA partly depends on a real time tracking control mechanism, since deviant intermediate action of the robot reduced SoA over the tone
Excretion patterns of coccidian oocysts and nematode eggs during the reproductive season in Northern Bald Ibis (Geronticus eremita)
Individual reproductive success largely depends on the ability to optimize behaviour, immune function and the physiological stress response. We have investigated correlations between behaviour, faecal steroid metabolites, immune parameters, parasite excretion patterns and reproductive output in a critically endangered avian species, the Northern Bald Ibis (Geronticus eremita). In particular, we related haematocrit, heterophil/lymphocyte ratio, excreted immune-reactive corticosterone metabolites and social behaviour with parasite excretion and two individual fitness parameters, namely, number of eggs laid and number of fledglings. We found that the frequency of excretion of parasites’ oocysts and eggs tended to increase with ambient temperature. Paired individuals excreted significantly more samples containing nematode eggs than unpaired ones. The excretion of nematode eggs was also significantly more frequent in females than in males. Individuals with a high proportion of droppings containing coccidian oocysts were more often preened by their partners than individuals with lower excretion rates. We observed that the more eggs an individual incubated and the fewer offspring fledged, the higher the rates of excreted samples containing coccidian oocysts. Our results confirm that social behaviour, physiology and parasite burden are linked in a complex and context-dependent manner. They also contribute background information supporting future conservation programmes dealing with this critically endangered species
Origins of the Ambient Solar Wind: Implications for Space Weather
The Sun's outer atmosphere is heated to temperatures of millions of degrees,
and solar plasma flows out into interplanetary space at supersonic speeds. This
paper reviews our current understanding of these interrelated problems: coronal
heating and the acceleration of the ambient solar wind. We also discuss where
the community stands in its ability to forecast how variations in the solar
wind (i.e., fast and slow wind streams) impact the Earth. Although the last few
decades have seen significant progress in observations and modeling, we still
do not have a complete understanding of the relevant physical processes, nor do
we have a quantitatively precise census of which coronal structures contribute
to specific types of solar wind. Fast streams are known to be connected to the
central regions of large coronal holes. Slow streams, however, appear to come
from a wide range of sources, including streamers, pseudostreamers, coronal
loops, active regions, and coronal hole boundaries. Complicating our
understanding even more is the fact that processes such as turbulence,
stream-stream interactions, and Coulomb collisions can make it difficult to
unambiguously map a parcel measured at 1 AU back down to its coronal source. We
also review recent progress -- in theoretical modeling, observational data
analysis, and forecasting techniques that sit at the interface between data and
theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue
connected with a 2016 ISSI workshop on "The Scientific Foundations of Space
Weather." 44 pages, 9 figure
PHIP - a novel candidate breast cancer susceptibility locus on 6q14.1
Most non-BRCA1/2 breast cancer families have no identified genetic cause. We used linkage and haplotype analyses in familial and sporadic breast cancer cases to identify a susceptibility locus on chromosome 6q. Two independent genome-wide linkage analysis studies suggested a 3 Mb locus on chromosome 6q and two unrelated Swedish families with a LOD > 2 together seemed to share a haplotype in 6q14.1. We hypothesized that this region harbored a rare high-risk founder allele contributing to breast cancer in these two families. Sequencing of DNA and RNA from the two families did not detect any pathogenic mutations. Finally, 29 SNPs in the region were analyzed in 44,214 cases and 43,532 controls from BCAC, and the original haplotypes in the two families were suggested as low-risk alleles for European and Swedish women specifically. There was also some support for one additional independent moderate-risk allele in Swedish familial samples. The results were consistent with our previous findings in familial breast cancer and supported a breast cancer susceptibility locus at 6q14.1 around the PHIP gene.Peer reviewe
The reference frame for encoding and retention of motion depends on stimulus set size
YesThe goal of this study was to investigate the reference
frames used in perceptual encoding and storage of visual
motion information. In our experiments, observers viewed
multiple moving objects and reported the direction of motion
of a randomly selected item. Using a vector-decomposition
technique, we computed performance during smooth pursuit
with respect to a spatiotopic (nonretinotopic) and to a
retinotopic component and compared them with performance
during fixation, which served as the baseline. For the stimulus
encoding stage, which precedes memory, we found that the
reference frame depends on the stimulus set size. For a single
moving target, the spatiotopic reference frame had the most
significant contribution with some additional contribution
from the retinotopic reference frame. When the number of
items increased (Set Sizes 3 to 7), the spatiotopic reference
frame was able to account for the performance. Finally, when
the number of items became larger than 7, the distinction
between reference frames vanished. We interpret this finding
as a switch to a more abstract nonmetric encoding of motion
direction. We found that the retinotopic reference frame was
not used in memory. Taken together with other studies, our
results suggest that, whereas a retinotopic reference frame
may be employed for controlling eye movements, perception
and memory use primarily nonretinotopic reference frames.
Furthermore, the use of nonretinotopic reference frames appears
to be capacity limited. In the case of complex stimuli, the
visual system may use perceptual grouping in order to simplify
the complexity of stimuli or resort to a nonmetric abstract
coding of motion information
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