2,258 research outputs found
Liturgia genetycznie wpisana w KoĹciĂłĹ
The article âLiturgy genetically imprinted in the Churchâ has been divided into four parts: 1. The Last Supper as the First Supper; 2. Corpus mysticum; 3. Ecclesiological and liturgical view of the paschal mystery; 4. Liturgy as a genetic fact. The paper shows that it is impossible to imagine the Church without the liturgy or the liturgy without the Church, since the Church, as a being, needs to have life i.e. the liturgy. The liturgy and the Church were created at the moment of Christâs paschal mystery. The liturgy is a gene of the Church; in other words, the liturgy gives life to the Church.ArtykuĹ âLiturgia genetycznie wpisana w KoĹciĂłĹâ zostaĹ podzielony na cztery czÄĹci: 1. Ostatnia Wieczerza PierwszÄ
WieczerzÄ
; 2. Corpus mysticum; 3. Eklezjologiczno-liturgiczne spojrzenie na misterium paschalne; 4. Liturgia jako fakt genetyczny. Opracowanie ukazuje, Ĺźe nie moĹźna wyobraziÄ sobie KoĹcioĹa bez liturgii i liturgii bez KoĹcioĹa, poniewaĹź KoĹcióŠjako byt musi mieÄ Ĺźycie, czyli liturgiÄ. Liturgia i KoĹcióŠpowstaĹy w momencie misterium paschalnego Chrystusa. Liturgia jest genem KoĹcioĹa, czyli liturgia daje Ĺźycie KoĹcioĹow
Growth dynamics and the evolution of cooperation in microbial populations
Microbes providing public goods are widespread in nature despite running the
risk of being exploited by free-riders. However, the precise ecological factors
supporting cooperation are still puzzling. Following recent experiments, we
consider the role of population growth and the repetitive fragmentation of
populations into new colonies mimicking simple microbial life-cycles.
Individual-based modeling reveals that demographic fluctuations, which lead to
a large variance in the composition of colonies, promote cooperation. Biased by
population dynamics these fluctuations result in two qualitatively distinct
regimes of robust cooperation under repetitive fragmentation into groups.
First, if the level of cooperation exceeds a threshold, cooperators will take
over the whole population. Second, cooperators can also emerge from a single
mutant leading to a robust coexistence between cooperators and free-riders. We
find frequency and size of population bottlenecks, and growth dynamics to be
the major ecological factors determining the regimes and thereby the
evolutionary pathway towards cooperation.Comment: 26 pages, 6 figure
Fast flowing populations are not well mixed
In evolutionary dynamics, well-mixed populations are almost always associated
with all-to-all interactions; mathematical models are based on complete graphs.
In most cases, these models do not predict fixation probabilities in groups of
individuals mixed by flows. We propose an analytical description in the
fast-flow limit. This approach is valid for processes with global and local
selection, and accurately predicts the suppression of selection as competition
becomes more local. It provides a modelling tool for biological or social
systems with individuals in motion.Comment: 19 pages, 8 figure
Critical dynamics in the evolution of stochastic strategies for the iterated Prisoner's Dilemma
The observed cooperation on the level of genes, cells, tissues, and
individuals has been the object of intense study by evolutionary biologists,
mainly because cooperation often flourishes in biological systems in apparent
contradiction to the selfish goal of survival inherent in Darwinian evolution.
In order to resolve this paradox, evolutionary game theory has focused on the
Prisoner's Dilemma (PD), which incorporates the essence of this conflict. Here,
we encode strategies for the iterated Prisoner's Dilemma (IPD) in terms of
conditional probabilities that represent the response of decision pathways
given previous plays. We find that if these stochastic strategies are encoded
as genes that undergo Darwinian evolution, the environmental conditions that
the strategies are adapting to determine the fixed point of the evolutionary
trajectory, which could be either cooperation or defection. A transition
between cooperative and defective attractors occurs as a function of different
parameters such a mutation rate, replacement rate, and memory, all of which
affect a player's ability to predict an opponent's behavior.Comment: 27 pages, including supplementary information. 5 figures, 4 suppl.
figures. Version accepted for publication in PLoS Comp. Bio
Conservative management versus open reduction and internal fixation for mid-shaft clavicle fractures in adults - The Clavicle Trial: Study protocol for a multicentre randomized controlled trial
Background: Clavicle fractures account for around 4% of all fractures and up to 44% of fractures of the shoulder girdle. Fractures of the middle third (or mid-shaft) account for approximately 80% of all clavicle fractures. Management of this group of fractures is often challenging and the outcome can be unsatisfactory. In particular it is not clear whether surgery produces better outcomes than non-surgical management. Currently there is much variation in the use of surgery and a lack of good quality evidence to inform our decision.Methods/Design: We aim to undertake a multicentre randomised controlled trial evaluating the effectiveness and safety of conservative management versus open reduction and internal fixation for displaced mid-shaft clavicle fractures in adults. Surgical treatment will be performed using the Acumed clavicle fixation system. Conservative management will consist of immobilisation in a sling at the side in internal rotation for 6 weeks or until clinical or radiological union. We aim to recruit 300 patients. These patients will be followed-up for at least 9 months. The primary endpoint will be the rate of non-union at 3 months following treatment. Secondary endpoints will be limb function measured using the Constant-Murley Score and the Disabilities of the Arm, Shoulder and Hand (DASH) Score at 3 and 9 months post-operatively.Discussion: This article presents the protocol for a multicentre randomised controlled trial. It gives extensive details of, and the basis for, the chosen methods, and describes the key measures taken to avoid bias and to ensure validity.Trial Registration: United Kingdom Clinical Research Network ID: 8665. The date of registration of the trial is 07/09/2006. The date the first patient was recruited is 18/12/2007. Š 2011 Longo et al; licensee BioMed Central Ltd
Altruism can proliferate through group/kin selection despite high random gene flow
The ways in which natural selection can allow the proliferation of
cooperative behavior have long been seen as a central problem in evolutionary
biology. Most of the literature has focused on interactions between pairs of
individuals and on linear public goods games. This emphasis led to the
conclusion that even modest levels of migration would pose a serious problem to
the spread of altruism in group structured populations. Here we challenge this
conclusion, by analyzing evolution in a framework which allows for complex
group interactions and random migration among groups. We conclude that
contingent forms of strong altruism can spread when rare under realistic group
sizes and levels of migration. Our analysis combines group-centric and
gene-centric perspectives, allows for arbitrary strength of selection, and
leads to extensions of Hamilton's rule for the spread of altruistic alleles,
applicable under broad conditions.Comment: 5 pages, 2 figures. Supplementary material with 50 pages and 26
figure
Calculating Evolutionary Dynamics in Structured Populations
Evolution is shaping the world around us. At the core of every evolutionary process is a population of reproducing individuals. The outcome of an evolutionary process depends on population structure. Here we provide a general formula for calculating evolutionary dynamics in a wide class of structured populations. This class includes the recently introduced âgames in phenotype spaceâ and âevolutionary set theory.â There can be local interactions for determining the relative fitness of individuals, but we require global updating, which means all individuals compete uniformly for reproduction. We study the competition of two strategies in the context of an evolutionary game and determine which strategy is favored in the limit of weak selection. We derive an intuitive formula for the structure coefficient, Ď, and provide a method for efficient numerical calculation
The biological origin of linguistic diversity
In contrast with animal communication systems, diversity is characteristic of almost every aspect of human language. Languages variously employ tones, clicks, or manual signs to signal differences in meaning; some languages lack the noun-verb distinction (e.g., Straits Salish), whereas others have a proliferation of fine-grained syntactic categories (e.g., Tzeltal); and some languages do without morphology (e.g., Mandarin), while others pack a whole sentence into a single word (e.g., Cayuga). A challenge for evolutionary biology is to reconcile the diversity of languages with the high degree of biological uniformity of their speakers. Here, we model processes of language change and geographical dispersion and find a consistent pressure for flexible learning, irrespective of the language being spoken. This pressure arises because flexible learners can best cope with the observed high rates of linguistic change associated with divergent cultural evolution following human migration. Thus, rather than genetic adaptations for specific aspects of language, such as recursion, the coevolution of genes and fast-changing linguistic structure provides the biological basis for linguistic diversity. Only biological adaptations for flexible learning combined with cultural evolution can explain how each child has the potential to learn any human language
A thermodynamic unification of jamming
Fragile materials ranging from sand to fire-retardant to toothpaste are able
to exhibit both solid and fluid-like properties across the jamming transition.
Unlike ordinary fusion, systems of grains, foams and colloids jam and cease to
flow under conditions that still remain unknown. Here we quantify jamming via a
thermodynamic approach by accounting for the structural ageing and the
shear-induced compressibility of dry sand. Specifically, the jamming threshold
is defined using a non-thermal temperature that measures the 'fluffiness' of a
granular mixture. The thermodynamic model, casted in terms of pressure,
temperature and free-volume, also successfully predicts the entropic data of
five molecular glasses. Notably, the predicted configurational entropy avoids
the Kauzmann paradox entirely. Without any free parameters, the proposed
equation-of-state also governs the mechanism of shear-banding and the
associated features of shear-softening and thickness-invariance.Comment: 16 pgs double spaced. 4 figure
Mobility promotes and jeopardizes biodiversity in rock-paper-scissors games
Biodiversity is essential to the viability of ecological systems. Species
diversity in ecosystems is promoted by cyclic, non-hierarchical interactions
among competing populations. Such non-transitive relations lead to an evolution
with central features represented by the `rock-paper-scissors' game, where rock
crushes scissors, scissors cut paper, and paper wraps rock. In combination with
spatial dispersal of static populations, this type of competition results in
the stable coexistence of all species and the long-term maintenance of
biodiversity. However, population mobility is a central feature of real
ecosystems: animals migrate, bacteria run and tumble. Here, we observe a
critical influence of mobility on species diversity. When mobility exceeds a
certain value, biodiversity is jeopardized and lost. In contrast, below this
critical threshold all subpopulations coexist and an entanglement of travelling
spiral waves forms in the course of temporal evolution. We establish that this
phenomenon is robust, it does not depend on the details of cyclic competition
or spatial environment. These findings have important implications for
maintenance and evolution of ecological systems and are relevant for the
formation and propagation of patterns in excitable media, such as chemical
kinetics or epidemic outbreaks.Comment: Final submitted version; the printed version can be found at
http://dx.doi.org/10.1038/nature06095 Supplementary movies are available at
http://www.theorie.physik.uni-muenchen.de/lsfrey/images_content/movie1.AVI
and
http://www.theorie.physik.uni-muenchen.de/lsfrey/images_content/movie2.AV
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