Search results for " evolution"
showing 10 items of 9699 documents
Stronger C -odd color charge correlations in the proton at higher energy
2023
The non-forward eikonal scattering matrix for dipole-proton scattering at high energy obtains an imaginary part due to a $C$-odd three gluon exchange. We present numerical estimates for the perturbative Odderon amplitude as a function of dipole size, impact parameter, their relative azimuthal angle, and light-cone momentum cutoff $x$. The proton is approximated as $\psi_\mathrm{qqq}|qqq\rangle + \psi_\mathrm{qqqg}|qqqg\rangle$, where $\psi_\mathrm{qqq}$ is a non-perturbative three quark model wave function while the gluon emission is computed in light-cone perturbation theory. We find that the Odderon amplitude increases as $x$ decreases from 0.1 to 0.01. At yet lower $x$, the reversal of t…
Genome degeneration and adaptation in a nascent stage of symbiosis
2014
Symbiotic associations between animals and microbes are ubiquitous in nature, with an estimated 15% of all insect species harboring intracellular bacterial symbionts. Most bacterial symbionts share many genomic features including small genomes, nucleotide composition bias, high coding density, and a paucity of mobile DNA, consistent with long-term host association. In this study, we focus on the early stages of genome degeneration in a recently derived insect-bacterial mutualistic intracellular association. We present the complete genome sequence and annotation of Sitophilus oryzae primary endosymbiont (SOPE). We also present the finished genome sequence and annotation of strain HS, a close…
Spatial variation in the evolutionary potential and constraints of basal metabolic rate and body mass in a wild bird
2023
An organism's energy budget is strongly related to resource consumption, performance, and fitness. Hence, understanding the evolution of key energetic traits, such as basal metabolic rate (BMR), in natural populations is central for understanding life-history evolution and ecological processes. Here we used quantitative genetic analyses to study evolutionary potential of BMR in two insular populations of the house sparrow (Passer domesticus). We obtained measurements of BMR and body mass (Mb) from 911 house sparrows on the islands of Leka and Vega along the coast of Norway. These two populations were the source populations for translocations to create an additional third, admixed ‘common ga…
Quantum Correlation Dynamics in Controlled Two-Coupled-Qubit Systems
2020
We study and compare the time evolutions of concurrence and quantum discord in a driven system of two interacting qubits prepared in a generic Werner state. The corresponding quantum dynamics is exactly treated and manifests the appearance and disappearance of entanglement. Our analytical treatment transparently unveils the physical reasons for the occurrence of such a phenomenon, relating it to the dynamical invariance of the X structure of the initial state. The quantum correlations which asymptotically emerge in the system are investigated in detail in terms of the time evolution of the fidelity of the initial Werner state.
Analysis of MAC-level throughput in LTE systems with link rate adaptation and HARQ protocols
2015
LTE is rapidly gaining momentum for building future 4G cellular systems, and real operational networks are under deployment worldwide. To achieve high throughput performance, in addition to an advanced physical layer design LTE exploits a combination of sophisticated mechanisms at the radio resource management layer. Clearly, this makes difficult to develop analytical tools to accurately assess and optimise the user perceived throughput under realistic channel assumptions. Thus, most existing studies focus only on link-layer throughput or consider individual mechanisms in isolation. The main contribution of this paper is a unified modelling framework of the MAC-level downlink throughput of …
Device-to-device communication for LTE-advanced network system
2014
Device-to-device (D2D) communication has been proposed as a mean for local connections in future ellular networks in order to provide improved throughput, spectrum savings, and longer battery lives. Here we widen the investigations of D2D communication to a 3GPP Long Term Evolution (LTE) system simulated in the interference limited macro-cellular environment, in which D2D communication is applied with D2D specific power control and resource allocation schemes and with a wide range of deployment ratios. Furthermore, we introduce channel model parameters applicable for a fair performance comparison between conventional cellular and D2D enhanced systems. The simulation results demonstrate that…
From Mobile Crimes to Crimes of Mobility
2020
Piipponen, Mäntymäki and Rodi-Risberg suggest that many contemporary crime narratives across the globe host a heightened interest in diverse and ambiguous mobilities, border crossings and borderlands. They propose that such mobilities and crossings reflect on recent sociocultural developments on local and global levels and communicate specific geopolitical anxieties. They position their own mobilities research perspective within existing crime fiction scholarship, especially within the so-called transnational and spatial turns. Introducing some key observations of mobilities research, they suggest that mobility can be considered both as an object of study in its own right and a critical len…
Biological and Mechanical Characterization of the Random Positioning Machine (RPM) for Microgravity Simulations
2021
The rapid improvement of space technologies is leading to the continuous increase of space missions that will soon bring humans back to the Moon and, in the coming future, toward longer interplanetary missions such as the one to Mars. The idea of living in space is charming and fascinating; however, the space environment is a harsh place to host human life and exposes the crew to many physical challenges. The absence of gravity experienced in space affects many aspects of human biology and can be reproduced in vitro with the help of microgravity simulators. Simulated microgravity (s-μg) is applied in many fields of research, ranging from cell biology to physics, including cancer biology. In…
Fatty acid composition as biomarkers of freshwater microalgae: analysis of 37 strains of microalgae in 22 genera and in seven classes
2013
The fatty acid (FA) composition of algae is an important determinant of their food quality for consumers, and FAs can also be used as biomarkers for biochemical and energetic pathways in food webs. FA analyses of 7 freshwater algal classes and 37 strains showed clear similarity within classes and strong differences amongst classes. Class was a dominant factor (66.4%) explaining variation in FA signatures of microalgae. The 7 algal classes comprised 4 separate groups according to their FA profiles: (1) Chlorophyceae and Trebouxiophyceae, (2) Bacillariophyceae, (3) Cryptophyceae, Chrysophyceae, and Raphidophyceae, and (4) Euglenophyceae. Each group had a characteristic FA composition, althoug…
Adaptation to fluctuations in temperature by nine species of bacteria.
2017
Abstract Rapid environmental fluctuations are ubiquitous in the wild, yet majority of experimental studies mostly consider effects of slow fluctuations on organism. To test the evolutionary consequences of fast fluctuations, we conducted nine independent experimental evolution experiments with bacteria. Experimental conditions were same for all species, and we allowed them to evolve either in fluctuating temperature alternating rapidly between 20°C and 40°C or at constant 30°C temperature. After experimental evolution, we tested the performance of the clones in both rapid fluctuation and in constant environments (20°C, 30°C and 40°C). Results from experiments on these nine species were comb…