539 research outputs found
The pattern of social fluidity within the British class structure: a topological model
It has previously been shown that across three British birth cohorts, relative rates of intergenerational social class mobility have remained at an essentially constant level among men and also among women who have worked only full-time. We aim now to establish the pattern of this prevailing level of social fluidity and its sources and to determine whether it too persists over time, and to bring out its implications for inequalities in relative mobility chances. We develop a parsimonious model for the log odds ratios which express the associations between individuals’ class origins and destinations. This model is derived from a topological model that comprises three kinds of readily interpretable binary characteristics and eight effects in all, each of which does, or does not, apply to particular cells of the mobility table: i.e. effects of class hierarchy, class inheritance and status affinity. Results show that the pattern as well as the level of social fluidity is essentially unchanged across the cohorts; that gender differences in this prevailing pattern are limited; and that marked differences in the degree of inequality in relative mobility chances arise with long-range transitions where inheritance effects are reinforced by hierarchy effects that are not offset by status affinity effects
Double beta decay versus cosmology: Majorana CP phases and nuclear matrix elements
We discuss the relation between the absolute neutrino mass scale, the
effective mass measured in neutrinoless double beta decay, and the Majorana CP
phases. Emphasis is placed on estimating the upper bound on the nuclear matrix
element entering calculations of the double beta decay half life. Consequently,
one of the Majorana CP phases can be constrained when combining the claimed
evidence for neutrinoless double beta decay with the neutrino mass bound from
cosmology.Comment: 11 pages, 3 figure
The mobility problem in Britain: new findings from the analysis of birth cohort data
Social mobility is now a matter of greater political concern in Britain than at any time previously. However, the data available for the determination of mobility trends are less adequate today than two or three decades ago. It is widely believed in political and in media circles that social mobility is in decline. But the evidence so far available from sociological research, focused on intergenerational class mobility, is not supportive of this view. We present results based on a newly-constructed dataset covering four birth cohorts that provides improved data for the study of trends in class mobility and that also allows analyses to move from the twentieth into the twenty-first century. These results confirm that there has been no decline in mobility, whether considered in absolute or relative terms. In the case of women, there is in fact evidence of mobility increasing. However, the better quality and extended range of our data enable us to identify other ‘mobility problems’ than the supposed decline. Among the members of successive cohorts, the experience of absolute upward mobility is becoming less common and that of absolute downward mobility more common; and class-linked inequalities in relative chances of mobility and immobility appear wider than previously thought
GAUSSPY+: A fully automated Gaussian decomposition package for emission line spectra
Our understanding of the dynamics of the interstellar medium is informed by the study of the detailed velocity structure of emission line observations. One approach to study the velocity structure is to decompose the spectra into individual velocity components; this leads to a description of the data set that is significantly reduced in complexity. However, this decomposition requires full automation lest it become prohibitive for large data sets, such as Galactic plane surveys. We developed GAUSSPY+, a fully automated Gaussian decomposition package that can be applied to emission line data sets, especially large surveys of HI and isotopologues of CO. We built our package upon the existing GAUSSPY algorithm and significantly improved its performance for noisy data. New functionalities of GAUSSPY+ include: (i) automated preparatory steps, such as an accurate noise estimation, which can also be used as stand-alone applications; (ii) an improved fitting routine; (iii) an automated spatial refitting routine that can add spatial coherence to the decomposition results by refitting spectra based on neighbouring fit solutions. We thoroughly tested the performance of GAUSSPY+ on synthetic spectra and a test field from the Galactic Ring Survey. We found that GAUSSPY+ can deal with cases of complex emission and even low to moderate signal-to-noise values
Soil bacterial community in potato tuberosphere following repeated applications of a common scab suppressive antagonist
Disease suppressive soils are important for managing soil-borne diseases that cannot be controlled with chemicals. One such disease is the potato common scab caused by Streptomyces species. Suppressiveness against common scab can develop spontaneously in fields where potato is grown for years without interruption, and this has been attributed to non-pathogenic Streptomyces strains. Streptomyces spp. have been used as inoculants in biological control, but their long-term effects have gained less attention. In our previous studies, a nonpathogenic Streptomyces strain (Str272) isolated from a potato common scab lesion suppressed common scab in field trials lasting over 5 years. In this study, bacterial communities in the tuberosphere i.e. in the soil adjacent to potato tubers, were analysed by next generation sequencing (NGS). The aim was to compare bacterial communities in untreated control plots to those in which seed tubers were treated with Str272 in one or several growing seasons. Str272 applications increased soil bacterial diversity and affected the bacterial composition in the potato tuberosphere. The most pronounced differences were observed between the untreated control and the treatments in which the antagonist had been applied in three or four consecutive years. The differences remained similar until the following growing season. Bacterial composition after repeated antagonist applications was associated with lower common scab severity. The antagonist applications had no or only slight effect on the number or abundance of OTUs belonging to Actinobacteria or Streptomyces, and no differences in quantities of pathogenic Streptomyces populations were detected by qPCR. This indicates that suppression of common scab by Str272 may not be based on direct effect on the common scab pathogens but is more likely to be associated with the alterations of the soil bacterial community. The most abundant bacteria phyla in the potato tuberosphere were Actinobacteria, Proteobacteria and Acidobacteria. However, the OTUs responding greatest to the antagonist treatments belonged to Bacterioidetes and Gemmatimonadetes. Results indicate that repeated applications of Str272 can change the bacterial community in the potato tuberosphere and lead to development of soil that is suppressive against potato common scab for several growing seasons after the last application.Peer reviewe
Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages
Background: Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and its lytic bacteriophage, along with two bacteriovorous protists with distinct feeding modes: Tetrahymena thermophila (particle feeder) and Acanthamoeba castellanii (surface feeder). The results were further confirmed with another study system with Pseudomonas and Tetrahymena thermophila. Results: We found that selection by protist predators lowered the susceptibility to infections by lytic phages in Serratia and Pseudomonas. In Serratia, concurrent selection by phages and protists led to lowered susceptibility to phage infections and this effect was independent from whether the bacteria shared a co-evolutionary history with the phage population or not. Bacteria that had evolved with phages were overall more susceptible to phage infection (compared to bacteria with history with multiple enemies) but they were less vulnerable to the phages they had co-evolved with than ancestral phages. Selection by bacterial enemies was costly in general and was seen as a lowered fitness in absence of phages, measured as a biomass yield. Conclusions: Our results show the significance of multiple species interactions on pairwise consumer-resource interaction, and suggest potential overlap in defending against predatory and parasitic enemies in microbial consumer-resource communities. Ultimately, our results could have larger scale effects on eco-evolutionary community dynamics.Peer reviewe
The detection and modeling of direct effects in latent class analysis
Several approaches have been proposed for latent class modeling with external variables, including one-step, two-step and three-step estimators. However, very little is known yet about the performance of these approaches when direct effects of the external variable to the indicators of latent class membership are present. In the current article, we compare those approaches and investigate the consequences of not modeling these direct effects when present, as well as the power of residual and fir statistics to identify such effects. The results of the simulations show that not modeling direct effect can lead to severe parameter bias, especially with a weak measurement model. Both residual and fit statistics can be used to identify such effects, as long as the number and strength of these effects is low and the measurement model is sufficiently strong
Ranking of physiotherapeutic evaluation methods as outcome measures of stifle functionality in dogs
BACKGROUND: Various physiotherapeutic evaluation methods are used to assess the functionality of dogs with stifle problems. Neither validity nor sensitivity of these methods has been investigated. This study aimed to determine the most valid and sensitive physiotherapeutic evaluation methods for assessing functional capacity in hind limbs of dogs with stifle problems and to serve as a basis for developing an indexed test for these dogs. A group of 43 dogs with unilateral surgically treated cranial cruciate ligament deficiency and osteoarthritic findings was used to test different physiotherapeutic evaluation methods. Twenty-one healthy dogs served as the control group and were used to determine normal variation in static weight bearing and range of motion. The protocol consisted of 14 different evaluation methods: visual evaluation of lameness, visual evaluation of diagonal movement, visual evaluation of functional active range of motion and difference in thrust of hind limbs via functional tests (sit-to-move and lie-to-move), movement in stairs, evaluation of hind limb muscle atrophy, manual evaluation of hind limb static weight bearing, quantitative measurement of static weight bearing of hind limbs with bathroom scales, and passive range of motion of hind limb stifle (flexion and extension) and tarsal (flexion and extension) joints using a universal goniometer. The results were compared with those from an orthopaedic examination, force plate analysis, radiographic evaluation, and a conclusive assessment. Congruity of the methods was assessed with a combination of three statistical approaches (Fisher’s exact test and two differently calculated proportions of agreeing observations), and the components were ranked from best to worst. Sensitivities of all of the physiotherapeutic evaluation methods against each standard were calculated. RESULTS: Evaluation of asymmetry in a sitting and lying position, assessment of muscle atrophy, manual and measured static weight bearing, and measurement of stifle passive range of motion were the most valid and sensitive physiotherapeutic evaluation methods. CONCLUSIONS: Ranking of the various physiotherapeutic evaluation methods was accomplished. Several of these methods can be considered valid and sensitive when examining the functionality of dogs with stifle problems
Developing a testing battery for measuring dogs' stifle functionality : the Finnish Canine Stifle Index (FCSI)
This study aimed at developing a quantitative testing battery for dogs' stifle functionality, as, unlike in human medicine, currently none is available in the veterinary field. Forty-three dogs with surgically treated unilateral cranial cruciate ligament rupture and 21 dogs with no known musculoskeletal problems were included. Eight previously studied tests: compensation in sitting and lying positions, symmetry of thrust in hindlimbs when rising from lying and sitting, static weight bearing, stifle flexion and extension and muscle mass symmetry, were summed into the Finnish Canine Stifle Index (FCSI). Sensitivities and specificities of the dichotomised FCSI score were calculated against orthopaedic examination, radiological and force platform analysis and a conclusive assessment (combination of previous). One-way analysis of variance (ANOVA)was used to evaluate FCSI score differences between the groups. Cronbach's alpha for internal consistency was calculated. The range of the index score was 0-263, with a proposed cut-off value of 60 between 'adequate' and 'compromised' functional performance. In comparison to the conclusive assessment, the sensitivity and specificity of the FCSI were 90 per cent and 90.5 per cent, respectively. Cronbach's alpha for internal reliability of the FCSI score was 0.727. An estimate of the surgically treated and control dogs' FCSI scores were 105 (95 per cent CI 93 to 116) and 20 (95 per cent CI 4 to 37), respectively. The difference between the groups was significant (PPeer reviewe
Asymptotic step profiles from a nonlinear growth equation for vicinal surfaces
We study a recently proposed nonlinear evolution equation describing the
collective step meander on a vicinal surface subject to the Bales-Zangwill
growth instability [O. Pierre-Louis et al., Phys. Rev. Lett. (80), 4221
(1998)]. A careful numerical analysis shows that the dynamically selected step
profile consists of sloped segments, given by an inverse error function and
steepening as sqrt(t), which are matched to pieces of a stationary
(time-independent) solution describing the maxima and minima. The effect of
smoothening by step edge diffusion is included heuristically, and a
one-parameter family of evolution equations is introduced which contains
relaxation by step edge diffusion and by attachment-detachment as special
cases. The question of the persistence of an initially imposed meander
wavelength is investigated in relation to recent experiments.Comment: 4 pages, 5 included figures. Typo in Eq.(5) corrected, section
headlines added and Ref.[12] update
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