On the energy dissipation of charge density wave systems and topological insulator surfaces

Dissipation mechanisms in a broad spectrum of physical systems and media attracted great interest among fundamental scientific and applied communities. Understanding the origin of various energy dissipation (non-contact friction) mechanism is still a wide-open problem. The frictional nature of layered systems, such as those hosting charge density wave (CDW) and topologically protected surface state, awaits to be investigated. Regarding CDW, I investigated non-contact energy dissipation on 1T-TaS2 surface. I studied the origin of dissipation on two phases of CDW and the effect of Mott insulating state on dissipated power. The low-temperature experimental results indicate that on a strongly pinned commensurate CDW phase, Joule dissipation is the main dissipation mechanism. The character of dissipation changes at room temperature and for nearly commensurate CDW phase. There the fluctuation driven dissipation is the main dissipation channel. The room temperature spectroscopy performed on the nearly commensurate phase of charge density wave indicates that the source of the fluctuating force and dissipation is the stochastic motion of weakly pinned charge density waves. Next, I studied the electronic nature of Bi2Te3 surface and energy dissipation on this topologically protected surface. I observed the suppression of the common Joule type losses due to a topologically protected surface state, which prevents electron scattering into the bulk states. It was found that dissipated power is related to the presence of image potential states that are found in the gap between the tip and the sample. The study shows that the damping coefficient increases due to charge fluctuation in the system when image potential states get populated via a single or few-electron tunneling process. Furthermore, the application of magnetic fields leads to the breaking of the topologically protected surface state and the rise of the Joule dissipation. Last, I report on the observation of dissipation peaks at selected voltage-dependent tip-surface distances on the oxygen-deficient strontium titanate (SrTiO3) surface. The experiment was performed at low temperatures (T=5K). The observed dissipation peaks are attributed to tip-induced charge state transitions in quantum-dot-like entities formed by a 2D system of single oxygen vacancies present at the SrTiO3 surface

Migration Scenario Narratives

A considerable amount of literature has been published on global and migration scenarios in recent decades. Central to the migration scenarios and narratives are the concepts of migration drivers and migration dynamics. Demographic, economic, technological, social, political, and environmental developments and complex interrelations between these domains are considered essential in creating plausible future migration developments. This report provides a set of internally consistent and evidence-based qualitative scenario narratives.The narratives are built on consistent demographic, socio-economic, environmental and political alternate futures generated for the EU and developing countries based on the qualitative and quantitative evidence gathered in the FUME project. Each narrative describes the future for the EU and developing countries in the short-term until 2030 and in the long-term between 2030 and 2050. These alternative futures are complemented by the potential changes in the future migratory demand and pressure from the expert survey conducted in the project and the characteristics of future migrants from the Delphi survey.<br/

Bayesian Multi-Dimensional Mortality Reconstruction

Even though mortality differentials by socio-economic status and educational attainment level have been widely examined, this research is often limited to developed countries and recent years. This is primarily due to the absence of consistently good-quality inherent data. Systematic studies with a broad geographical and temporal spectrum that engage with the link between educational attainment and mortality are lacking. In this paper, we propose a mortality rates reconstruction model based on multiple patchy data sources, and provide mortality rates by level of education. The proposed model is a hierarchical Bayesian model that combines the strengths of multiple sources in order to disaggregate mortality rates by time periods, age groups, sex and educational attainment. We apply the model in a case study that includes 13 countries across South-East Europe, Western Asia and North Africa, and calculate education-specific mortality rates for five-year age groups starting at age 15 for the 1980-2015 time period. Furthermore, we evaluate the model’s performance relying on standard convergence indicators and trace plots, and validate our estimates via posterior predictive checks. This study contributes to the literature by proposing a novel methodology to enhance the research on the relationship between education and adult mortality. It addresses the lack of educations-pecific mortality differentials by providing a flexible method for their estimation

A model to analyze the use value of enclosed outdoor spaces

Bu &ccedil;alışmada binalarla tanımlanmış dış mekanlardaki kullanım değerinin &ouml;nceki araştırma sonu&ccedil;larından elde edilen fakt&ouml;rlerle ilişkisi incelenmiştir. Kullanım değeri kavramı etkinliklerin &ccedil;eşitliliği, etkinliklerin sıklığı, kullanım yoğunluğu ve mekanda kalış s&uuml;resiyle tanımlanmıştır. Kullanım değeri &uuml;zerinde etkili olabilecek fakt&ouml;rler fiziksel nitelikler, tanımlanmışlık, estetik-g&ouml;rsel nitelikler, yaya hareketi, bağlam, planlanmış etkinlikler, zaman aralığı ve kullanıcı profili olarak saptanmıştır. Araştırmanın problem alanı eko-davranışsal yaklaşımın belirlediği kuramsal &ccedil;er&ccedil;eveye dayandırılmıştır. Kampus &ccedil;evrelerinde y&uuml;r&uuml;t&uuml;len araştırmanın bulguları binalarla tanımlı dış mekanların kullanım değeri &uuml;zerinde &ccedil;eşitli derecelerde etkisi olan fakt&ouml;rlerin bir arada &ccedil;alışarak bir model oluşturabileceğini g&ouml;stermiştir. Bu analiz modeli binalarla tanımlı dış mekanların kullanım değerini saptamak ve değerlendirmek i&ccedil;in kullanılabilir.&nbsp;Anahtar kelimeler: Binalarla tanımlı dış mekanlar, kullanım değeri, eko-davranışsal yaklaşım, kampus &ccedil;evreleri, fakt&ouml;rler ve fiziksel nitelikler.This study examines the dependency of ?use value? of enclosed outdoor spaces on some presumed factors, which are derived from an existing body of literature and earlier research results. The use value of enclosed outdoor spaces is described as a combination of, activity diversity, frequency of activities, use density and occupancy time. Physical features, enclosure, spatial layout, aesthetic/ visual quality, pedestrian movement, context, planned activities, period of time and user profile are considered as factors that can be influential on the use value. The problems of this research have been approached from the perspective of eco-behavioral approach. The case study was conducted at campus environments. This research proved that there are many factors which are influential on the use value of enclosed outdoor space; and these factors, every one of which has an effect on the use value to varying degrees, working together,  may establish an analysis model to determine and evaluate the use value of enclosed outdoor spaces. While proving the significance of the factors mentioned above, this study also revealed new effects such as proximity to the high activity buildings, visibility-the presence of good viewing areas, presence of other people, attachment to the space, and sittable and shaded space. The proposed model can also give guidance to the designer and orient future research as well.  Keywords: Enclosed outdoor spaces, use value, eco-behavioral approach, campus environment, factors and physical features

A flexible model to reconstruct education-specific fertility rates: Sub-Saharan Africa case

The future world population growth and size will be largely determined by the pace of fertility decline in sub-Saharan Africa. Correct estimates of education-specific fertility rates are crucial for projecting the future population. Yet, consistent cross-country comparable estimates of education-specific fertility for sub-Saharan African countries are still lacking. We propose a flexible Bayesian hierarchical model to reconstruct education-specific fertility rates by using the patchy Demographic and Health Surveys (DHS) data and the United Nations’ (UN) reliable estimates of total fertility rates (TFR). Our model produces estimates that match the UN TFR to different extents (in other words, estimates of varying levels of consistency with the UN). We present three model specifications: consistent but not identical with the UN, fully-consistent (nearly identical) with the UN, and consistent with the DHS. Further, we provide a full time series of education-specific TFR estimates covering five-year periods between 1980 and 2014 for 36 sub-Saharan African countries. The results show that the DHS-consistent estimates are usually higher than the UN-fully-consistent ones. The differences between the three model estimates vary substantially in size across countries, yielding 1980-2014 fertility trends that differ from each other mostly in level only but in some cases also in direction

Unconstrained image reconstruction with resolution modelling does not have a unique solution

<b>Background</b>: Social media data is a promising source of social science data. However, deriving the demographic characteristics of users and dealing with the nonrandom, nonrepresentative populations from which they are drawn represent challenges for social scientists. <b>Objective</b>: Given the growing use of social media data in social science research, this paper asks two questions: 1) To what extent are findings obtained with social media data generalizable to broader populations, and 2) what is the best practice for estimating demographic information from Twitter data? <b>Methods</b>: Our analyses use information gathered from 979,992 geo-located Tweets sent by 22,356 unique users in South East England between 23 June and 4 July 2014. We estimate demographic characteristics of the Twitter users with the crowd-sourcing platform CrowdFlower and the image-recognition software Face++. To evaluate bias in the data, we run a series of log-linear models with offsets and calibrate the nonrepresentative sample of Twitter users with mid-year population estimates for South East England. <b>Results</b>: CrowdFlower proves to be more accurate than Face++ for the measurement of age, whereas both tools are highly reliable for measuring the sex of Twitter users. The calibration exercise allows bias correction in the age-, sex-, and location-specific population counts obtained from the Twitter population by augmenting Twitter data with mid-year population estimates. <b>Contribution</b>: The paper proposes best practices for estimating Twitter users' basic demographic characteristics and a calibration method to address the selection bias in the Twitter population, allowing researchers to generalize findings based on Twitter to the general population

Ortaokul Matematik Öğretmen Adaylarının Sabit Değişen Şekil Örüntüsü Genellemesini Öğretmek İçin Matematik Bilgileri

DergiPark: 453416tredÖğretmen adaylarının cebirsel düşünme ile ilgili hem kendi bilgilerinihem de öğrenciler hakkında bilgilerini ortaya koymak, kavramsal bilgiye sahipolan öğretmenler yetiştirmek için ilk aşama sayılabilir. Bu amaçla buçalışmada, ortaokul matematik öğretmeni adaylarının örüntü genellemesihakkındaki konu alan ve pedagojik alan bilgileri incelenmiştir. Nitel araştırmatasarımı kapsamında, 26 öğretmen adayına sabit değişen şekil örüntüsü problemive bu problemle ilişkili olarak açık uçlu sorular sorulmuştur. Elde edilenveriler, Ball, Thames ve Phelps (2008) tarafından geliştirilen “Öğretmek içinMatematiksel Bilgi (ÖMB)” modeli kullanılarak içerik analizi ile incelenmiştir.Bulgular, öğretmen adaylarının tümünün örüntüyü cebirsel olarak doğrugenelleyebildiklerini ortaya koymuştur. Çoğunun genellemeye ulaşırken sayısalakıl yürütme kullandığı tespit edilmiştir. Öğretmen adaylarının, öğrencilerinproblem çözme konusundaki bilgilerinin, genellikle kendi çözüm yöntemlerinedayandığı görülmüştür. Öğretmen adaylarının, öğrencilerin yaşayabileceği zorlukve kavram yanılgılarına yönelik tahminleri oldukça sınırlıdır. Dolayısıylabunları gidermek için yaptıkları öneriler de yetersiz kalmıştır. Bulgularadayanarak, öğretmen adaylarını yetiştirmeye yönelik öneriler yapılmıştır

The Clinical Value of Flow Cytometric DNA Content Analysis in Patients with Soft Tissue Sarcomas

Purpose. The purpose of this study was to evaluate: (1) the correlation between grade and ploidy or S-phase fraction (SPF), (2) the prognostic value of DNA flow cytometric study in soft tissue sarcomas

Quantifying the impact of COVID-19 on immigration in receiving high-income countries

Previous studies have examined the impact of COVID-19 on mortality and fertility. However, little is known about the effect of the pandemic on constraining international migration. We use Eurostat and national statistics data on immigration and ARIMA time-series models to quantify the impact of COVID-19 on immigration flows in 15 high-income countries by forecasting their counterfactual levels in 2020, assuming no pandemic, and comparing these estimates with observed immigration counts. We then explore potential driving forces, such as stringency measures and increases in unemployment moderating the extent of immigration change. Our results show that immigration declined in all countries, except in Finland. Yet, significant cross-national variations exist. Australia (60%), Spain (45%) and Sweden (36%) display the largest declines, while immigration decreased by between 15% and 30% in seven countries, and by less than 15% in four nations where results were not statistically significant. International travel restrictions, mobility restrictions and stay-at-home requirements exhibit a relatively strong relationship with declines in immigration, although countries with similar levels of stringency witnessed varying levels of immigration decline. Work and school closings and unemployment show no relationship with changes in immigration