233 research outputs found
Cooperation, Norms, and Revolutions: A Unified Game-Theoretical Approach
Cooperation is of utmost importance to society as a whole, but is often
challenged by individual self-interests. While game theory has studied this
problem extensively, there is little work on interactions within and across
groups with different preferences or beliefs. Yet, people from different social
or cultural backgrounds often meet and interact. This can yield conflict, since
behavior that is considered cooperative by one population might be perceived as
non-cooperative from the viewpoint of another.
To understand the dynamics and outcome of the competitive interactions within
and between groups, we study game-dynamical replicator equations for multiple
populations with incompatible interests and different power (be this due to
different population sizes, material resources, social capital, or other
factors). These equations allow us to address various important questions: For
example, can cooperation in the prisoner's dilemma be promoted, when two
interacting groups have different preferences? Under what conditions can costly
punishment, or other mechanisms, foster the evolution of norms? When does
cooperation fail, leading to antagonistic behavior, conflict, or even
revolutions? And what incentives are needed to reach peaceful agreements
between groups with conflicting interests?
Our detailed quantitative analysis reveals a large variety of interesting
results, which are relevant for society, law and economics, and have
implications for the evolution of language and culture as well
The O/OREOS Mission - Astrobiology in Low Earth Orbit
The O/OREOS (Organism/Organic Exposure to Orbital Stresses) nanosatellite is the first science demonstration spacecraft and flight mission of the NASA Astrobiology Small- Payloads Program (ASP). O/OREOS was launched successfully on November 19, 2010, to a high-inclination (72), 650-km Earth orbit aboard a US Air Force Minotaur IV rocket from Kodiak, Alaska. O/OREOS consists of 3 conjoined cubesat (each 1000 cu.cm) modules: (i) a control bus, (ii) the Space Environment Survivability of Living Organisms (SESLO) experiment, and (iii) the Space Environment Viability of Organics (SEVO) experiment. Among the innovative aspects of the O/OREOS mission are a real-time analysis of the photostability of organics and biomarkers and the collection of data on the survival and metabolic activity for micro-organisms at 3 times during the 6-month mission. We will report on the spacecraft characteristics, payload capabilities and first operational phase of the O/OREOS mission. The science and technology rationale of O/OREOS supports NASAs scientific exploration program by investigating the local space environment as well as space biology relevant to Moon and Mars missions. It also serves as precursor for experiments on small satellites, the International Space Station (ISS), future free-flyers and lunar surface exposure facilities
What Goes in Must Come out: Testing for Biases in Molecular Analysis of Arbuscular Mycorrhizal Fungal Communities
Arbuscular mycorrhizal (AM) fungi are widely distributed microbes that form obligate symbioses with the majority of
terrestrial plants, altering nutrient transfers between soils and plants, thereby profoundly affecting plant growth and
ecosystem properties. Molecular methods are commonly used in the study of AM fungal communities. However, the biases
associated with PCR amplification of these organisms and their ability to be utilized quantitatively has never been fully
tested. We used Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis to characterise artificial community
templates containing known quantities of defined AM fungal genotypes. This was compared to a parallel in silico analysis
that predicted the results of this experiment in the absence of bias. The data suggest that when used quantitatively the
TRFLP protocol tested is a powerful, repeatable method for AM fungal community analysis. However, we suggest some
limitations to its use for population-level analyses. We found no evidence of PCR bias, supporting the quantitative use of
other PCR-based methods for the study of AM fungi such as next generation amplicon sequencing. This finding greatly
improves our confidence in methods that quantitatively examine AM fungal communities, providing a greater
understanding of the ecology of these important fungi
Measurement of flavor asymmetry of light-quark sea in the proton with Drell-Yan dimuon production in and collisions at 120 GeV
Evidence for a flavor asymmetry between the and quark
distributions in the proton has been found in deep-inelastic scattering and
Drell-Yan experiments. The pronounced dependence of this flavor asymmetry on
(fraction of nucleon momentum carried by partons) observed in the Fermilab
E866 Drell-Yan experiment suggested a drop of the ratio in the region. We report results from the
SeaQuest Fermilab E906 experiment with improved statistical precision for in the large region up to
using the 120 GeV proton beam. Two different methods for extracting the
Drell-Yan cross section ratios, , from the SeaQuest
data give consistent results. The ratios and the differences are deduced from these cross section ratios for
. The SeaQuest and E866/NuSea ratios are in good agreement for the
region. The new SeaQuest data, however, show that
continues to be greater than up to the highest value
(). The new results on and are
compared with various parton distribution functions and theoretical
calculations
Calcium-containing phosphopeptides pave the secretory pathway for efficient protein traffic and secretion in fungi
High-Throughput High-Resolution Class I HLA Genotyping in East Africa
HLA, the most genetically diverse loci in the human genome, play a crucial role in host-pathogen interaction by mediating innate and adaptive cellular immune responses. A vast number of infectious diseases affect East Africa, including HIV/AIDS, malaria, and tuberculosis, but the HLA genetic diversity in this region remains incompletely described. This is a major obstacle for the design and evaluation of preventive vaccines. Available HLA typing techniques, that provide the 4-digit level resolution needed to interpret immune responses, lack sufficient throughput for large immunoepidemiological studies. Here we present a novel HLA typing assay bridging the gap between high resolution and high throughput. The assay is based on real-time PCR using sequence-specific primers (SSP) and can genotype carriers of the 49 most common East African class I HLA-A, -B, and -C alleles, at the 4-digit level. Using a validation panel of 175 samples from Kampala, Uganda, previously defined by sequence-based typing, the new assay performed with 100% sensitivity and specificity. The assay was also implemented to define the HLA genetic complexity of a previously uncharacterized Tanzanian population, demonstrating its inclusion in the major East African genetic cluster. The availability of genotyping tools with this capacity will be extremely useful in the identification of correlates of immune protection and the evaluation of candidate vaccine efficacy
The interpretations and uses of fitness landscapes in the social sciences
__Abstract__
This working paper precedes our full article entitled “The evolution of Wright’s (1932) adaptive field to contemporary interpretations and uses of fitness landscapes in the social sciences” as published in the journal Biology & Philosophy (http://link.springer.com/article/10.1007/s10539-014-9450-2). The working paper features an extended literature overview of the ways in which fitness landscapes have been interpreted and used in the social sciences, for which there was not enough space in the full article. The article features an in-depth philosophical discussion about the added value of the various ways in which fitness landscapes are used in the social sciences. This discussion is absent in the current working paper. Th
Flaxseed supplementation improved insulin resistance in obese glucose intolerant people: a randomized crossover design
<p>Abstract</p> <p>Background</p> <p>Obesity leads to an increase in inflammation and insulin resistance. This study determined antioxidant activity of flaxseed and its role in inflammation and insulin resistance in obese glucose intolerant people.</p> <p>Methods</p> <p>Using a randomized crossover design, nine obese glucose intolerant people consumed 40 g ground flaxseed or 40 g wheat bran daily for 12 weeks with a 4-week washout period. Plasma inflammation biomarkers (CRP, TNF-α, and IL-6), glucose, insulin, and thiobaribituric acid reactive substance (TBARS) were measured before and after of each supplementation.</p> <p>Results</p> <p>Flaxseed supplementation decreased TBARS (p = 0.0215) and HOMA-IR (p = 0.0382). Flaxseed or wheat bran supplementation did not change plasma inflammatory biomarkers. A positive relationship was found between TBARS and HOMA-IR (r = 0.62, p = 0.0003).</p> <p>Conclusions</p> <p>The results of the study weakly support that decreased insulin resistance might have been secondary to antioxidant activity of flaxseed. However, the mechanism(s) of decreased insulin resistance by flaxseed should be further determined using flaxseed lignan.</p
- …