162 research outputs found
Transhumant pastoralism in Poland: Contemporary challenges
Since the mid-2000s, transhumant pastoralism and the production of artisanal sheepâs cheeses have experienced a revival in the Polish Carpathians. This revival has largely coincided with Polandâs accession to the European Union in 2004, leading to a re-valuation of extensive livestock production from an economic and environmental liability to a form of âHigh Nature Valueâ farming. Supported by Common Agricultural Policy CAP European Union subsidies, Polish pastoralists have been re-classified from being producers of livestock and agricultural products to suppliers of environmental and ecosystem services. Despite these changes, however, they continue to face significant systemic challenges which are rooted in the marked decline of the communist-era pastoral economy in the late 1980s and a subsequent increasing competition for land and labour under market conditions. Based on anthropological fieldwork conducted in Polandâs Carpathian Highland region during the 2015, 2016, and 2017 pastoral seasons, this article provides insight into four sets of challenges deemed most important by working shepherds today: recruiting qualified labour, gaining access to pasture, gaining access to markets, and working within a Polish policy environment which fails to recognise the particular conditions and requirements of pastoral agriculture
The efficacy of preopoerative instruction in reducing anxiety following gyneoncological surgery: a case control study
<p>Abstract</p> <p>Background</p> <p>This is a quasi-experimental case control research focusing on the impact of systematic preoperative instruction on the level of postoperative anxiety in gyneoncologic patients. The population studied consists of the gyneoncologic surgery patients admitted to the Gynecologic Oncology Service at Zekai Tahir Burak Gynecology Training and Research Hospital from May to September 2010.</p> <p>Patients and methods</p> <p>Through a random sampling, 60 patients were recruited in each group. The study group was given a systematic preoperative instruction while the control group was given routine nursing care. Patients were interviewed in the postoperative period and anxiety was measured. The data-collecting tool consisted of the Individual Information Form and the State-Trait Anxiety Inventory. The collected data were analyzed by using the SPSS Program to find the frequency, the percentage, the mean and the standard variables, and the hypothesis was tested with Chi-square, variance, and t-independent test.</p> <p>Results</p> <p>It was found that the incidence rates from the post-operative anxiety score of the study group were lower than those of the control group (p < .05). The results of this research demonstrated that gyneoncologic surgery patients who were given systematic preoperative instruction felt less anxious than the ones who were given merely a routine nursing care.</p> <p>Conclusions</p> <p>Results of this study suggest that preoperative instruction programs aiming at informing gyneoncologic surgery patients at the preoperative stage should be organized in hospitals and have an essential role.</p
A Gaussian-processes approach to fitting for time-variable spherical solar wind in pulsar timing data
Propagation effects are one of the main sources of noise in high-precision pulsar timing. For pulsars below an ecliptic latitude of 5°, the ionized plasma in the solar wind can introduce dispersive delays of order 100 ”s around solar conjunction at an observing frequency of 300âMHz. A common approach to mitigate this assumes a spherical solar wind with a time-constant amplitude. However, this has been shown to be insufficient to describe the solar wind. We present a linear, Gaussian-process piecewise Bayesian approach to fit a spherical solar wind of time-variable amplitude, which has been implemented in the pulsar software RUN_ENTERPRISE. Through simulations, we find that the current EPTA+InPTA data combination is not sensitive to such variations; however, solar wind variations will become important in the near future with the addition of new InPTA data and data collected with the low-frequency LOFAR telescope. We also compare our results for different high-precision timing data sets (EPTA+InPTA, PPTA, and LOFAR) of 3âms pulsars (J0030+0451, J1022+1001, J2145â0450), and find that the solar-wind amplitudes are generally consistent for any individual pulsar, but they can vary from pulsar to pulsar. Finally, we compare our results with those of an independent method on the same LOFAR data of the three millisecond pulsars. We find that differences between the results of the two methods can be mainly attributed to the modelling of dispersion variations in the interstellar medium, rather than the solar wind modelling
Same Trait, Different Receiver Response: Unlike Females, Male American Goldfinches Do Not Signal Status with Bill Colour
In species in which both sexes have similar ornamentation, the ornaments often function as sexual or social signals in both sexes. However, males and females may use ornaments in different signalling contexts. We previously demonstrated that carotenoid-based bill colour of female American goldfinches, Spinus tristis, functions as a signal of status during intrasexual, but not intersexual, competition. Here we test whether male bill colour functions as a competitive status signal during both intra- and intersexual contests. We tested whether focal males and females avoided feeding adjacent to taxidermic male models as a function of the modelsâ experimentally altered bill colour. We additionally tested whether male bill colour functions as a mate choice signal by presenting females with a choice of two live males with experimentally altered bill colour. In the status signal experiment, neither focal males nor females avoided male models with more colourful bills, as was predicted by the status-signalling hypothesis. These results indicate that male bill coloration does not function as a signal of competitive status and that the signal function of male bill colour does not parallel that of female bill colour. In our mate choice experiment, females showed no preference for male bill colour, suggesting that male bill colour may have some yet untested signalling function or that male bill colour may no longer be under selection. Our findings suggest that selection can lead to different signalling strategies in males and females, even in species that express mutual ornamentation
Practical approaches to analyzing PTA data: Cosmic strings with six pulsars
We search for a stochastic gravitational wave background (SGWB) generated by
a network of cosmic strings using six millisecond pulsars from Data Release 2
(DR2) of the European Pulsar Timing Array (EPTA). We perform a Bayesian
analysis considering two models for the network of cosmic string loops, and
compare it to a simple power-law model which is expected from the population of
supermassive black hole binaries. Our main strong assumption is that the
previously reported common red noise process is a SGWB. We find that the
one-parameter cosmic string model is slightly favored over a power-law model
thanks to its simplicity. If we assume a two-component stochastic signal in the
data (supermassive black hole binary population and the signal from cosmic
strings), we get a upper limit on the string tension of () for the two cosmic string models we consider. In extended
two-parameter string models, we were unable to constrain the number of kinks.
We test two approximate and fast Bayesian data analysis methods against the
most rigorous analysis and find consistent results. These two fast and
efficient methods are applicable to all SGWBs, independent of their source, and
will be crucial for analysis of extended data sets.Comment: 13 pages, 5 figure
The second data release from the European Pulsar Timing Array I. The dataset and timing analysis
Pulsar timing arrays offer a probe of the low-frequency gravitational wave
spectrum (1 - 100 nanohertz), which is intimately connected to a number of
markers that can uniquely trace the formation and evolution of the Universe. We
present the dataset and the results of the timing analysis from the second data
release of the European Pulsar Timing Array (EPTA). The dataset contains
high-precision pulsar timing data from 25 millisecond pulsars collected with
the five largest radio telescopes in Europe, as well as the Large European
Array for Pulsars. The dataset forms the foundation for the search for
gravitational waves by the EPTA, presented in associated papers. We describe
the dataset and present the results of the frequentist and Bayesian pulsar
timing analysis for individual millisecond pulsars that have been observed over
the last ~25 years. We discuss the improvements to the individual pulsar
parameter estimates, as well as new measurements of the physical properties of
these pulsars and their companions. This data release extends the dataset from
EPTA Data Release 1 up to the beginning of 2021, with individual pulsar
datasets with timespans ranging from 14 to 25 years. These lead to improved
constraints on annual parallaxes, secular variation of the orbital period, and
Shapiro delay for a number of sources. Based on these results, we derived
astrophysical parameters that include distances, transverse velocities, binary
pulsar masses, and annual orbital parallaxes.Comment: 29 pages, 9 figures, 13 tables, Astronomy & Astrophysics in pres
Practical approaches to analyzing PTA data: Cosmic strings with six pulsars
We search for a stochastic gravitational wave background (SGWB) generated by a network of cosmic strings using six millisecond pulsars from Data Release 2 (DR2) of the European Pulsar Timing Array (EPTA). We perform a Bayesian analysis considering two models for the network of cosmic string loops, and compare it to a simple power-law model which is expected from the population of supermassive black hole binaries. Our main strong assumption is that the previously reported common red noise process is a SGWB. We find that the one-parameter cosmic string model is slightly favored over a power-law model thanks to its simplicity. If we assume a two-component stochastic signal in the data (supermassive black hole binary population and the signal from cosmic strings), we get a 95% upper limit on the string tension of log10(GΌ)<-9.9 (-10.5) for the two cosmic string models we consider. In extended two-parameter string models, we were unable to constrain the number of kinks. We test two approximate and fast Bayesian data analysis methods against the most rigorous analysis and find consistent results. These two fast and efficient methods are applicable to all SGWBs, independent of their source, and will be crucial for analysis of extended datasets
Quantifying Variability of Avian Colours: Are Signalling Traits More Variable?
Background
Increased variability in sexually selected ornaments, a key assumption of evolutionary theory, is thought to be maintained through condition-dependence. Condition-dependent handicap models of sexual selection predict that (a) sexually selected traits show amplified variability compared to equivalent non-sexually selected traits, and since males are usually the sexually selected sex, that (b) males are more variable than females, and (c) sexually dimorphic traits more variable than monomorphic ones. So far these predictions have only been tested for metric traits. Surprisingly, they have not been examined for bright coloration, one of the most prominent sexual traits. This omission stems from computational difficulties: different types of colours are quantified on different scales precluding the use of coefficients of variation.
Methodology/Principal Findings
Based on physiological models of avian colour vision we develop an index to quantify the degree of discriminable colour variation as it can be perceived by conspecifics. A comparison of variability in ornamental and non-ornamental colours in six bird species confirmed (a) that those coloured patches that are sexually selected or act as indicators of quality show increased chromatic variability. However, we found no support for (b) that males generally show higher levels of variability than females, or (c) that sexual dichromatism per se is associated with increased variability.
Conclusions/Significance
We show that it is currently possible to realistically estimate variability of animal colours as perceived by them, something difficult to achieve with other traits. Increased variability of known sexually-selected/quality-indicating colours in the studied species, provides support to the predictions borne from sexual selection theory but the lack of increased overall variability in males or dimorphic colours in general indicates that sexual differences might not always be shaped by similar selective forces
The second data release from the European Pulsar Timing Array IV. Search for continuous gravitational wave signals
We present the results of a search for continuous gravitational wave signals
(CGWs) in the second data release (DR2) of the European Pulsar Timing Array
(EPTA) collaboration. The most significant candidate event from this search has
a gravitational wave frequency of 4-5 nHz. Such a signal could be generated by
a supermassive black hole binary (SMBHB) in the local Universe. We present the
results of a follow-up analysis of this candidate using both Bayesian and
frequentist methods. The Bayesian analysis gives a Bayes factor of 4 in favor
of the presence of the CGW over a common uncorrelated noise process, while the
frequentist analysis estimates the p-value of the candidate to be 1%, also
assuming the presence of common uncorrelated red noise. However, comparing a
model that includes both a CGW and a gravitational wave background (GWB) to a
GWB only, the Bayes factor in favour of the CGW model is only 0.7. Therefore,
we cannot conclusively determine the origin of the observed feature, but we
cannot rule it out as a CGW source. We present results of simulations that
demonstrate that data containing a weak gravitational wave background can be
misinterpreted as data including a CGW and vice versa, providing two plausible
explanations of the EPTA DR2 data. Further investigations combining data from
all PTA collaborations will be needed to reveal the true origin of this
feature.Comment: 12 figures, 15 pages, to be submitte
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