Optimizing periodicity and polymodality in noise-induced genetic oscillators

Many cellular functions are based on the rhythmic organization of biological processes into self-repeating cascades of events. Some of these periodic processes, such as the cell cycles of several species, exhibit conspicuous irregularities in the form of period skippings, which lead to polymodal distributions of cycle lengths. A recently proposed mechanism that accounts for this quantized behavior is the stabilization of a Hopf-unstable state by molecular noise. Here we investigate the effect of varying noise in a model system, namely an excitable activator-repressor genetic circuit, that displays this noise-induced stabilization effect. Our results show that an optimal noise level enhances the regularity (coherence) of the cycles, in a form of coherence resonance. Similar noise levels also optimize the multimodal nature of the cycle lengths. Together, these results illustrate how molecular noise within a minimal gene regulatory motif confers robust generation of polymodal patterns of periodicity.Comment: 9 pages, 6 figure

Evaluating Current Logistics Facilities with Analytical Hyepapchy Process (AHP) and Geographical Information Systems (GIS)

Abstract. Logistics facilities which have important position within logistics supply chain are established in order for the demanded goods to be supplied on time, with the minimum cost and in the shortest duration. Given the cost and time factors, the location of such facilities should be selected very carefully and effectively. Especially, a quick settlement in logistics manner is experienced depending on transportation network, work force, proximity to market and raw materials of the times following the industrialization period after establishing the Republic. Nowadays, with the development of transportation and the communication systems as well as technology transportation costs decreased and the facilities and possibilities transport from one place to another increased. For this reason, like the private sector the public institutions and organizations began to shrink, shut down or merge their facilities. This situation was brought to reconsider the existing facilities. The purpose of this study is to evaluate and analyze current six logistics facilities with Analytical Hierarchy Process (AHP) and Geographical Information Systems (GIS). Analyses results will contribute the decision of revising logistics facilities for which are planned to be restructured. Moreover, suggestions are presented for proper ones to continue operating, for improper ones to get closed or transferred to another place.Keywords. Analytic Hierarchy Process, (AHP), Geographic Information Systems, (GIS), Facility Site Selection.JEL. J61, L86, Q55

Surface structure of 45 Hercules: An otherwise unremarkable Ap star with a surprisingly weak magnetic field

The origin of magnetic fields and their role in chemical spot formation on magnetic Ap stars is currently not understood. Here we contribute to solving this problem with a detailed observational characterisation of the surface structure of 45 Her, a weak-field Ap star. We find this object to be a long-period, single-lined spectroscopic binary and determine the binary orbit as well as fundamental and atmospheric parameters of the primary. We study magnetic field topology and chemical spot distribution of 45 Her with the help of the Zeeman Doppler imaging technique. Magnetic mapping reveals the stellar surface field to have a distorted dipolar topology with a surface-averaged field strength of 77 G and a dipolar component strength of 119 G - confirming it as one of the weakest well-characterised Ap-star fields known. Despite its feeble magnetic field, 45 Her shows surface chemical inhomogeneities with abundance contrasts of up to 6 dex. Of the four chemical elements studied, O concentrates at the magnetic equator whereas Ti, Cr and Fe avoid this region. Apart from this trend, the positions of Fe-peak element spots show no apparent correlation with the magnetic field geometry. No signs of surface differential rotation or temporal evolution of chemical spots on the time scale of several years were detected. Our findings demonstrate that chemical spot formation does not require strong magnetic fields to proceed and that both the stellar structure and the global field itself remain stable for sub-100 G field strengths contrary to theoretical predictions.Comment: 15 pages, 19 figures; Accepted for publication in MNRA

An ensemble of eddy-permitting global ocean reanalyses from the MyOcean project

A set of four eddy-permitting global ocean reanalyses produced in the framework of the MyOcean project have been compared over the altimetry period 1993–2011. The main differences among the reanalyses used here come from the data assimilation scheme implemented to control the ocean state by inserting reprocessed observations of sea surface temperature (SST), in situ temperature and salinity profiles, sea level anomaly and sea-ice concentration. A first objective of this work includes assessing the interannual variability and trends for a series of parameters, usually considered in the community as essential ocean variables: SST, sea surface salinity, temperature and salinity averaged over meaningful layers of the water column, sea level, transports across pre-defined sections, and sea ice parameters. The eddy-permitting nature of the global reanalyses allows also to estimate eddy kinetic energy. The results show that in general there is a good consistency between the different reanalyses. An intercomparison against experiments without data assimilation was done during the MyOcean project and we conclude that data assimilation is crucial for correctly simulating some quantities such as regional trends of sea level as well as the eddy kinetic energy. A second objective is to show that the ensemble mean of reanalyses can be evaluated as one single system regarding its reliability in reproducing the climate signals, where both variability and uncertainties are assessed through the ensemble spread and signal-to-noise ratio. The main advantage of having access to several reanalyses differing in the way data assimilation is performed is that it becomes possible to assess part of the total uncertainty. Given the fact that we use very similar ocean models and atmospheric forcing, we can conclude that the spread of the ensemble of reanalyses is mainly representative of our ability to gauge uncertainty in the assimilation methods. This uncertainty changes a lot from one ocean parameter to another, especially in global indices. However, despite several caveats in the design of the multi-system ensemble, the main conclusion from this study is that an eddy-permitting multi-system ensemble approach has become mature and our results provide a first step towards a systematic comparison of eddy-permitting global ocean reanalyses aimed at providing robust conclusions on the recent evolution of the oceanic state

Reversible and Noisy Progression towards a Commitment Point Enables Adaptable and Reliable Cellular Decision-Making

Cells must make reliable decisions under fluctuating extracellular conditions, but also be flexible enough to adapt to such changes. How cells reconcile these seemingly contradictory requirements through the dynamics of cellular decision-making is poorly understood. To study this issue we quantitatively measured gene expression and protein localization in single cells of the model organism Bacillus subtilis during the progression to spore formation. We found that sporulation proceeded through noisy and reversible steps towards an irreversible, all-or-none commitment point. Specifically, we observed cell-autonomous and spontaneous bursts of gene expression and transient protein localization events during sporulation. Based on these measurements we developed mathematical population models to investigate how the degree of reversibility affects cellular decision-making. In particular, we evaluated the effect of reversibility on the 1) reliability in the progression to sporulation, and 2) adaptability under changing extracellular stress conditions. Results show that reversible progression allows cells to remain responsive to long-term environmental fluctuations. In contrast, the irreversible commitment point supports reliable execution of cell fate choice that is robust against short-term reductions in stress. This combination of opposite dynamic behaviors (reversible and irreversible) thus maximizes both adaptable and reliable decision-making over a broad range of changes in environmental conditions. These results suggest that decision-making systems might employ a general hybrid strategy to cope with unpredictably fluctuating environmental conditions

The psychology and policy of overcoming economic inequality

Data and materials’ availability: All data are publicly available for the survey data used (https://osf.io/njd62/) and from the UN Gender Inequality Index (https://hdr.undp.org/data-center/documentation-and-downloads). Financial transaction data were provided through an agreement with Columbia Business School.Recent arguments claim that behavioral science has focused – to its detriment – on the individual over the system when construing behavioral interventions. In this commentary, we argue that tackling economic inequality using both framings in tandem is invaluable. By studying individuals who have overcome inequality, “positive deviants,” and the system limitations they navigate, we offer potentially greater policy solutions.This research was supported in part by the National Science Foundation (no. 2218595) and by Undergraduate Global Engagement at Columbia University. Additional support was provided to individual researchers from the Columbia University Office of the Provost, Masaryk University Centre for International Cooperation, and the Benjamin A. Gilman International Fund from the United States Department of State

The persistence of cognitive biases in financial decisions across economic groups

Data availability: All data will be posted open access via https://psyarxiv.com/mrxy6/ and in interactive form via https://public.tableau.com/app/profile/kai.ruggeri. We will post these only once an accepted version of all analyses is possible to avoid confusion based on version control.While economic inequality continues to rise within countries, efforts to address it have been largely ineffective, particularly those involving behavioral approaches. It is often implied but not tested that choice patterns among low-income individuals may be a factor impeding behavioral interventions aimed at improving upward economic mobility. To test this, we assessed rates of ten cognitive biases across nearly 5000 participants from 27 countries. Our analyses were primarily focused on 1458 individuals that were either low-income adults or individuals who grew up in disadvantaged households but had above-average financial well-being as adults, known as positive deviants. Using discrete and complex models, we find evidence of no differences within or between groups or countries. We therefore conclude that choices impeded by cognitive biases alone cannot explain why some individuals do not experience upward economic mobility. Policies must combine both behavioral and structural interventions to improve financial well-being across populations.This research was supported in part by the National Science Foundation (#2218595) and by Undergraduate Global Engagement at Columbia University. Additional support was provided to individual researchers from the Columbia University Office of the Provost, Masaryk University Centre for International Cooperation, and the Benjamin A. Gilman International Fund from the United States Department of State. This research was funded in part, by the UKRI [MR/N013468/1]

An Innovative Solution for Transportation among Caspian Region

AbstractGlobalization and liberalization of the economies in worldwide raise the importance of transportation strategies to make difference in competitive environment. The rise of Asian economies attracted the attention of other countries. As a result of, the center of gravity of the World trade has shifted towards the east, Eurasian countries has appeared as ensuring sustainable economic growth by developing the trade relations among Eurasian countries as well as with other countries, and also European countries decided to expand the transport networks which facilitate trade relations. In line with these strategies, Asia-Europe transport corridor projects have been created. Some of these projects are; the Trans-European Transport Networks (TEN-T), Pan-European Corridors (PEC), Modern Silk Road and Europe-Caucasia-Asia Transport Corridor (TRACECA). But, there are deficiencies (like infrastructure, legislation) existing when these projects put into practice, and also, Caspian Sea (as an important land defect) necessitates intermodal transportation. In this paper, it has been aimed to examine alternative transportation lines in the region, reveal the current problems, and propose solutions within the context of infrastructure or transport policies. In scope of the study, qualitative research technique used, several visits were made to stakeholder countries to obtain data from field studies, and workshops were held as closed sessions

Midwifery students’ reactions to ethical dilemmas encountered in outpatient clinics

Background: Midwives are required to make ethical decisions with the support of respective codes of professional ethics which provide a framework for decision making in clinical practice. Whilst each midwife should be ethically aware and sensitive to the ever-changing issues within reproduction, few empirical studies have examined the views of student midwives in relation to reproductive ethical dilemmas. Objective: The aim of this study was to explore midwifery students’ reactions to a number of ethical dilemmas relating to women’s experiences of reproductive decision making. Design: A series of focus groups were conducted with midwifery students who were asked to discuss five culturally significant scenarios including issues of knowledge acquisition regarding methods of family planning, removal or insertion of an Intrauterine Device, and abortion. Setting: A University, Turkey. Participants: Purposeful sampling was adopted which resulted in five focus groups with a total of 57 midwifery students. Ethical considerations: The study was reviewed and granted formal ethical approval by an ethical committee at the Faculty of Health Science in Atatürk University. The head of the Faculty of Health Science approved the investigation. The participants received both oral and written information about the study and they gave their consent. Results: Five themes were identified from the analysis of the focus group data related to all five scenarios. These themes were: “The right to information”; “choice and protection”; “parental rights and welfare of the women”; “make a decision”; “women rights and sexual abuse”. Conclusions: This study has shown that whilst students respected women’s choice, they also expressed great ambivalence in some situations when personal values conflict with dominant societal beliefs and professional ethics. A focus on ethics education to include human rights is suggested as a means to enable students to explore their own social-value judgments, and as a means to limit the possible development of ethical confusion and moral distress