Traveling waves of in vitro evolving RNA.

Populations of short self-replicating RNA variants have been confined to one side of a reaction-diffusion traveling wave front propagating along thin capillary tubes containing the Q beta viral enzyme. The propagation speed is accurately measurable with a magnitude of about 1 micron/sec, and the wave persists for hundreds of generations (of duration less than 1 min). Evolution of RNA occurs in the wavefront, as established by front velocity changes and gel electrophoresis of samples drawn from along the capillary. The high population numbers (approximately equal to 10(11], their well-characterized biochemistry, their short generation time, and the constant conditions make the system ideal for evolution experiments. Growth is monitored continuously by excitation of an added RNA-sensitive fluorescent dye, ethidium bromide. An analytic expression for the front velocity is derived for the multicomponent kinetic scheme that reduces, for a high RNA-enzyme binding constant, to the Fisher form v = 2 square root of kappa D, where D is the diffusion constant of the complex and kappa is the low-concentration overall replication rate coefficient. The latter is confirmed as the selective value-determining parameter by numerical solution of a two-species system

Nuclear effects in atomic transitions

Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects that can be identified in atomic structure data. An introduction to the theory of isotope shifts and hyperfine splitting of atomic spectra is given, together with an overview of the typical experimental techniques used in high-precision atomic spectroscopy. More exotic effects at the borderline between atomic and nuclear physics, such as parity violation in atomic transitions due to the weak interaction, or nuclear polarization and nuclear excitation by electron capture, are also addressed.Comment: review article, 53 pages, 14 figure

The feasibility of daily monitoring in adolescents and young adults with mild intellectual disability or borderline intellectual functioning

BACKGROUND: It is unclear whether the limitations of young persons with a mild intellectual disability or borderline intellectual functioning preclude feasibility of the daily diary method.METHOD: For 60 consecutive days, 50 participants (M age  = 21.4, 56% male) who receive care in an ambulatory, residential, or juvenile detention setting, self-rated both standardised and personalised diary questions through an app. Diary entries were used for feedback in treatment. Interviews were used to explore acceptability. RESULTS: Average compliance was 70.4%, while 26% of participants dropped out. Compliance was good in ambulatory (88.9%) and residential care (75.6%), but not in the juvenile detention setting (19.4%). The content of self-selected diary items varied widely. Participants deemed the method acceptable.CONCLUSIONS: Daily monitoring is feasible for individuals with a mild intellectual disability or borderline intellectual functioning receiving ambulatory or residential care, and can provide scientists and practitioners with important insights into day-to-day behavioural patterns.</p

«Белая дача» А.П. Чехова – как часть культурного ландшафта Крыма

Данная работа написана в рамках научного проекта кафедры культурологии «Культурные ландшафты Крыма» и посвящена рассмотрению «Белой дачи» А.П. Чехова (ныне Дом-музей А.П. Чехова в Ялте) как культурному ландшафту – результату сотворчества человека и природы

Concept studie autonoom oogsten van appels en peren

Bij de oogst van appels en peren is in een korte periode veel arbeid nodig. Het vraagt een forse inspanning om voldoende kwalitatief juiste arbeid te krijgen op het juiste moment tegen de juiste prijs, de kosten voor arbeid zijn hoog. Voor NFO en het PT hebben initiatief genomen om te komen tot robotisering van deze handeling te automatiseren. Doelstelling van dit project is één of meerdere concepten te ontwerpen voor het automatisch oogsten van appels en peren, waarbij kritische deelfuncties op eerste haalbaarheid zijn getoetst om de drempel te verlagen om een vervolg te starten. Aansluitend is het doel ontwikkelingstraject te starten dat binnen een afzienbare periode zal leiden tot implementatie. In het rapport zijn enkele perspectiefvolle concepten uitgewerkt. Verschillende deelfuncties zijn ontworpen en getest op haalbaarheid zoals: het sensorconcept globaal (waar zitten de appels); het sensorconcept lokaal (Is de appel voldoende rijp); manipulatie en end-effector en logistiek en buffering. Voor de verschillende functies zijn goede oplossingen voorhanden. De studie betreft met name een papieren studie. In een vervolg zal moeten blijken of het ook daadwerkelijk technisch haalbaar is. De focus in een vervolg dient te liggen bij de plukhandeling zelf en de daarbij horende sensoriek (de ogen, de arm en het handje). Het afvoeren van de geoogste appels, het bufferen en het transport door de boomgaard lijkt niet het probleem te zijn. Aan het einde heeft een herijking van de businesscase plaatsgevonden. De NFO/PT acht het project voldoende perspectiefvol om te starten met een initiatief voor verdere implementatie als vervolg op de conceptontwikkeling

Retention of Antimicrobial Activity in Plaque and Saliva following Mouthrinse Use in vivo

The aim of this study was to determine the contribution of plaque and saliva towards the prolonged activity, also called substantivity, of three antimicrobial mouthrinses (Listerine (R), Meridol (R), Crest Pro Health (R)), used in combination with a toothpaste (Prodent Coolmint (R)). Volunteers brushed for 4 weeks with a toothpaste without antimicrobial claims, while during the last 2 weeks half of the volunteers used an antimicrobial mouthrinse in addition to brushing. At the end of the experimental period, plaque and saliva samples were collected 6 h after oral hygiene, and bacterial concentrations and viabilities were determined. The contribution of plaque and saliva towards substantivity was assessed by combining plaque obtained after mechanical cleaning only with plaque and saliva obtained after additional use of an antimicrobial rinse. Subsequently, resulting viabilities of the combined plaques were determined. The viabilities of plaque samples after additional rinsing with mouthrinses were lower than of plaque obtained after mechanical cleaning only, regardless of the rinse involved. Moreover, plaque collected 6 h after rinsing with antimicrobial mouthrinses contained a surplus of antimicrobial activity. Only Listerine showed decreased vi

Uphill and downhill walking in unilateral lower limb amputees

Objective: To study adjustment strategies in unilateral amputees in uphill and downhill walking. Design: observational cohort study. Subjects: Seven transfemoral, 12 transtibial unilateral amputees and 10 able-bodied subjects. Methods: In a motion analysis laboratory the subjects walked over a level surface and an uphill and downhill slope. Gait velocity and lower limb joint angles were measured. Results: In uphill walking hip and knee flexion at initial contact and hip flexion in swing were increased in the prosthetic limb of transtibial amputees. In downhill walking transtibial amputees showed more knee flexion on the prosthetic side in late stance and swing. Transfemoral amputees were not able to increase prosthetic knee flexion in uphill and downhill walking. An important adjustment strategy in both amputee Groups was a smaller hip extension in late stance in uphill and downhill walking, probably related with a shorter step length. In addition, amputees increased knee flexion in early stance in the non-affected limb in uphill walking to compensate for the shorter prosthetic limb length. In downhill walking fewer adjustments were necessary, since the shorter prosthetic limb already resulted in lowering of the body. Conclusion: Uphill and downhill walking can be trained in rehabilitation, which may improve safety and confidence of amputees. Prosthetic design should focus on better control of prosthetic knee flexion abilities without reducing stability. (c) 2007 Elsevier B.V. All fights reserved

Optimization by Quantum Annealing: Lessons from hard 3-SAT cases

The Path Integral Monte Carlo simulated Quantum Annealing algorithm is applied to the optimization of a large hard instance of the Random 3-SAT Problem (N=10000). The dynamical behavior of the quantum and the classical annealing are compared, showing important qualitative differences in the way of exploring the complex energy landscape of the combinatorial optimization problem. At variance with the results obtained for the Ising spin glass and for the Traveling Salesman Problem, in the present case the linear-schedule Quantum Annealing performance is definitely worse than Classical Annealing. Nevertheless, a quantum cooling protocol based on field-cycling and able to outperform standard classical simulated annealing over short time scales is introduced.Comment: 10 pages, 6 figures, submitted to PR

Search for Rayleigh scattering in the atmosphere of GJ1214b

We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet towards the blue. We observed the transit of GJ1214b in the B-band with the FOcal Reducing Spectrograph (FORS) at the Very Large Telescope (VLT) and in the g-band with both ACAM on the William Hershel Telescope (WHT) and the Wide Field Camera (WFC) at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B-band of 0.1162+/-0.0017, and in the g-band 0.1180+/-0.0009 and 0.1174+/-0.0017 for the WHT & INT observations respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered a small scale-height water-dominated model fits the data best.Comment: Accepted for publication in Ap