996 research outputs found
Auf dem Weg zur digitalen Stadt – Aufbau der digitalen Planungsinfrastruktur Hamburg
In dem „Zentralen Planungsinformationssystem Hamburg“ (PLIS-HH) werden rechtsgültige digitale georeferenzierte Planwerke des Bau- und Planungsrechtes (verbindliche und vorbereitende Bauleitpläne auf Basis des Baugesetzbuches (BauGB) / Bundesbaugesetzes (BBauG); Planwerke auf Basis alten Planrechts: Baustufenpläne, Durchführungspläne, Teilbebauungspläne; Erhaltungsverordnungen nach §172 BauGB und Gestaltungverordnungen nach §12 Hamburgische Bauordnung (HBauO)) erfasst und als Bestandteil der Geodateninfrastruktur der Freien und Hansestadt Hamburg (FHH) zentral in einer Geofachdatenhaltungskomponente in einer einheitlichen semantischen Struktur vorgehalten.
Diese zentrale Datenhaltung erlaubt gleichzeitig eine dezentrale Fortführung und Pflege der Datenbestände durch den jeweiligen Sachbearbeiter an seinem Arbeitsplatz, setzt aber die Entwicklung und Einrichtung vereinheitlichter und abgestimmter Datenaustausch- und Aktualisierungsprozesse voraus. Damit ist gewährleistet, dass alle in der FHH vorgehaltenen Auskunfts- und Monitoringsysteme, Beteiligungs- und Baugenehmigungsverfahren, die Bauleitpläne und sonstigen Verordnungen als Informationsbasis benötigen, eine einheitliche Datenbasis zur Verfügung haben. Eine arbeitsaufwändige Recherche nach aktuellem Planrecht und die damit verbundene Aktualisierung der Datenhaltung für die unterschiedlichen Fachinformationssysteme können somit zukünftig entfallen
Epigenetic Chromatin Silencing: Bistability and Front Propagation
The role of post-translational modification of histones in eukaryotic gene
regulation is well recognized. Epigenetic silencing of genes via heritable
chromatin modifications plays a major role in cell fate specification in higher
organisms. We formulate a coarse-grained model of chromatin silencing in yeast
and study the conditions under which the system becomes bistable, allowing for
different epigenetic states. We also study the dynamics of the boundary between
the two locally stable states of chromatin: silenced and unsilenced. The model
could be of use in guiding the discussion on chromatin silencing in general. In
the context of silencing in budding yeast, it helps us understand the phenotype
of various mutants, some of which may be non-trivial to see without the help of
a mathematical model. One such example is a mutation that reduces the rate of
background acetylation of particular histone side-chains that competes with the
deacetylation by Sir2p. The resulting negative feedback due to a Sir protein
depletion effect gives rise to interesting counter-intuitive consequences. Our
mathematical analysis brings forth the different dynamical behaviors possible
within the same molecular model and guides the formulation of more refined
hypotheses that could be addressed experimentally.Comment: 19 pages, 5 figure
Use of high throughput sequencing to observe genome dynamics at a single cell level
With the development of high throughput sequencing technology, it becomes
possible to directly analyze mutation distribution in a genome-wide fashion,
dissociating mutation rate measurements from the traditional underlying
assumptions. Here, we sequenced several genomes of Escherichia coli from
colonies obtained after chemical mutagenesis and observed a strikingly
nonrandom distribution of the induced mutations. These include long stretches
of exclusively G to A or C to T transitions along the genome and orders of
magnitude intra- and inter-genomic differences in mutation density. Whereas
most of these observations can be explained by the known features of enzymatic
processes, the others could reflect stochasticity in the molecular processes at
the single-cell level. Our results demonstrate how analysis of the molecular
records left in the genomes of the descendants of an individual mutagenized
cell allows for genome-scale observations of fixation and segregation of
mutations, as well as recombination events, in the single genome of their
progenitor.Comment: 22 pages, 9 figures (including 5 supplementary), one tabl
Relationship between cellular response and behavioral variability in bacterial chemotaxis
Bacterial chemotaxis in Escherichia coli is a canonical system for the study
of signal transduction. A remarkable feature of this system is the coexistence
of precise adaptation in population with large fluctuating cellular behavior in
single cells (Korobkova et al. 2004, Nature, 428, 574). Using a stochastic
model, we found that the large behavioral variability experimentally observed
in non-stimulated cells is a direct consequence of the architecture of this
adaptive system. Reversible covalent modification cycles, in which methylation
and demethylation reactions antagonistically regulate the activity of
receptor-kinase complexes, operate outside the region of first-order kinetics.
As a result, the receptor-kinase that governs cellular behavior exhibits a
sigmoidal activation curve. This curve simultaneously amplifies the inherent
stochastic fluctuations in the system and lengthens the relaxation time in
response to stimulus. Because stochastic fluctuations cause large behavioral
variability and the relaxation time governs the average duration of runs in
response to small stimuli, cells with the greatest fluctuating behavior also
display the largest chemotactic response. Finally, Large-scale simulations of
digital bacteria suggest that the chemotaxis network is tuned to simultaneously
optimize the random spread of cells in absence of nutrients and the cellular
response to gradients of attractant.Comment: 15 pages, 4 figures, Supporting information available here
http://cluzel.uchicago.edu/data/emonet/arxiv_070531_supp.pd
Parameters identification of unknown delayed genetic regulatory networks by a switching particle swarm optimization algorithm
The official published version can be found at the link below.This paper presents a novel particle swarm optimization (PSO) algorithm based on Markov chains and competitive penalized method. Such an algorithm is developed to solve global optimization problems with applications in identifying unknown parameters of a class of genetic regulatory networks (GRNs). By using an evolutionary factor, a new switching PSO (SPSO) algorithm is first proposed and analyzed, where the velocity updating equation jumps from one mode to another according to a Markov chain, and acceleration coefficients are dependent on mode switching. Furthermore, a leader competitive penalized multi-learning approach (LCPMLA) is introduced to improve the global search ability and refine the convergent solutions. The LCPMLA can automatically choose search strategy using a learning and penalizing mechanism. The presented SPSO algorithm is compared with some well-known PSO algorithms in the experiments. It is shown that the SPSO algorithm has faster local convergence speed, higher accuracy and algorithm reliability, resulting in better balance between the global and local searching of the algorithm, and thus generating good performance. Finally, we utilize the presented SPSO algorithm to identify not only the unknown parameters but also the coupling topology and time-delay of a class of GRNs.This research was partially supported by the National Natural Science Foundation of PR China (Grant No. 60874113), the Research Fund for the Doctoral Program of Higher Education (Grant No. 200802550007), the Key Creative Project of Shanghai Education Community (Grant No. 09ZZ66), the Key Foundation Project of Shanghai (Grant No. 09JC1400700), the Engineering and Physical Sciences Research Council EPSRC of the UK under Grant No. GR/S27658/01, the International Science and Technology Cooperation Project of China under Grant No. 2009DFA32050, an International Joint Project sponsored by the Royal Society of the UK, and the Alexander von Humboldt Foundation of Germany
Evaluation of Different Recruitment Methods: Longitudinal, Web-Based, Pan-European Physical Activity Through Sustainable Transport Approaches (PASTA) Project
ABSTRACT
Background: Sufficient sample size and minimal sample bias are core requirements for empirical data analyses. Combining opportunistic recruitment with a Web-based survey and data-collection platform yields new benefits over traditional recruitment approaches.
Objective: This paper aims to report the success of different recruitment methods and obtain data on participants’ characteristics, participation behavior, recruitment rates, and representativeness of the sample.
Methods: A longitudinal, Web-based survey was implemented as part of the European PASTA (Physical Activity through Sustainable Transport Approaches) project, between November 2014 and December 2016. During this period, participants were recruited from 7 European cities on a rolling basis. A standardized guide on recruitment strategy was developed for all cities, to reach a sufficient number of adult participants. To make use of the strengths and minimize weakness, a combination of different opportunistic recruitment methods was applied. In addition, the random sampling approach was applied in the city of Örebro. To reduce the attrition rate and improve real-time monitoring, the Web-based platform featured a participant’s and a researchers’ user interface and dashboard.
Results: Overall, 10,691 participants were recruited; most people found out about the survey through their workplace or employer (2300/10691, 21.51%), outreach promotion (2219/10691, 20.76%), and social media (1859/10691, 17.39%). The average number of questionnaires filled in per participant varied significantly between the cities (P<.001), with the highest number in Zurich (11.0, SE 0.33) and the lowest in Örebro (4.8, SE 0.17). Collaboration with local organizations, the use of Facebook and mailing lists, and direct street recruitment were the most effective approaches in reaching a high share of participants (P<.001). Considering the invested working hours, Facebook was one of the most time-efficient methods. Compared with the cities’ census data, the composition of study participants was broadly representative in terms of gender distribution; however, the study included younger and better-educated participants.
Conclusions: We observed that offering a mixed recruitment approach was highly effective in achieving a high participation rate. The highest attrition rate and the lowest average number of questionnaires filled in per participant were observed in Örebro, which also recruited participants through random sampling. These findings suggest that people who are more interested in the topic are more willing to participate and stay in a survey than those who are selected randomly and may not have a strong connection to the research topic. Although direct face-to-face contacts were very effective with respect to the number of recruited participants, recruiting people through social media was not only effective but also very time efficient. The collected data are based on one of the largest recruited longitudinal samples with a common recruitment strategy in different European cities
Moral Psychology and Politics: Evolved Moral Intuitions and Their Links to Contemporary Political Issues
This literature review thesis explores the evolutionary based theory of moral psychology called the Moral Foundations Theory and its innate processes that serve as factors in moral judgments regarding contemporary political issues. This thesis describes the theoretical foundations underlying the Moral Foundations approach, and then proceeds to review empirical sources on its general applicability. It then examines how the approach may be applied to political ideology, as well as the connection to the emotion of disgust. Next, the review continues to explore relations between pathogen and sexual disgust sensitivity and politics. The final section of the thesis body takes a close look at how moral foundations can be applied to climate and environmental issues. The studies reviewed also explored the impacts of framing different issues regarding the various foundations and how this may be a political tactic moving forward, further expressing the relevance of the Moral Foundations Theory. Future research should account for the wide range of political ideologies and broaden the knowledge on the cultural reach of the theory
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