Mehmet Levent Kurnaz

APPLICATION OF DETRENDED FLUCTUATION ANALYSIS TO MONTHLY AVERAGE OF THE MAXIMUM DAILY TEMPERATURES TO RESOLVE DIFFERENT CLIMATES

Detrended fluctuation analysis (DFA) is used to investigate correlations between the monthly average of the maximum daily temperatures for different locations in the continental United States and the different climates these locations have. When we plot the scaling exponents obtained from the DFA versus the standard deviation of the temperature fluctuations, we observe crowding of data points belonging to the same climates. Thus, we conclude that by observing the long-time trends in the fluctuations of temperature it would be possible to distinguish between different climates.

Detrended fluctuation analysis as a statistical tool to monitor the climate

Detrended fluctuation analysis is used to investigate the power law relationship between the monthly averages of the maximum daily temperatures for different locations in the western US. On the map created by the power law exponents, we can distinguish different geographical regions with different power law exponents. When the power law exponents obtained from the detrended fluctuation analysis are plotted versus the standard deviation of the temperature fluctuations, we observe different data points belonging to the different climates, hence indicating that by observing the long-time trends in the fluctuations of temperature we may be able to distinguish between different climates.

Certain Non-Standard Coding Tables Appear to be More Robust to Error Than the Standard Genetic Code

Since the identification of the Standard Coding Table as a “universal” method to translate genetic information into amino acids, exceptions to this rule have been reported, and to date there are nearly 20 alternative genetic coding tables deployed by either nuclear genomes or organelles of organisms. Why are these codes still in use and why are new codon reassignments occurring? This present study aims to provide a new method to address these questions and to analyze whether these alternative codes present any advantages or disadvantages to the organisms or organelles in terms of robustness to error. We show that two of the alternative coding tables, The Ciliate, Dasycladacean and Hexamita Nuclear Code (CDH) and The Flatworm Mitochondrial Code (FMC), exhibit an advantage, while others such as The Yeast Mitochondrial Code (YMC) are at a significant disadvantage. We propose that the Standard Code is likely to have emerged as a “local minimum” and that the “coding landscape” is still being searched for a “global” minimum.

Monte Carlo simulation and statistical analysis of genetic information coding

The rules that specify how the information contained in DNA codes amino acids, are called “the genetic code”. Using a simplified version of the Penna model, we are utilizing computer simulations to investigate the importance of the genetic code and the number of amino acids in Nature on population dynamics. We find that the genetic code is not a random pairing of codons to amino acids and the number of amino acids in Nature is an optimum under mutations.

Simulating the Climatology of Extreme Events for the Central Asia Domain Using the RegCM 4.0 Regional Climate Model

In this work, future changes in the frequency of the seasonal extreme climate events such as number, frequency, duration and intensity of heat waves (5 consecutive temperature days above the maximum temperature calendar day 90th percentiles, number of days per year that is above the same percentiles and greatest number of consecutive days above these percentiles) for the period of 2071–2100 over Central Asia (18.56°–70.13° East and 7.28°–142.4° North) with respect to the present period of 1971–2000 were studied in detail. Regional Climate Model RegCM 4.0 of Abdus Salam International Center for Theoretical Physics (ICTP) with ECHAM5 forcing data was used for hindcast and forecast projection. This region will very likely be affected by heat waves in winter and spring seasons and heat wave frequency, intensity and duration will increase significantly over the Arabian Peninsula in summer. On the other hand, cold spells will not change as much as heat waves over the region in all seasons.

SEDIMENTATION OF GLASS BEADS UNDER THE INFLUENCE OF GRAVITY

The quasi-two-dimensional sedimentation of 0.06 cm diameter silica spheres in viscous oil (between glass plates separated by a 1 mm gap) results in quasi-one dimensional rough surfaces. These surfaces are rough on all length-scales between the particle size and the cell size, but different roughness exponents are observed in each of two well defined regimes (αs=0.81±0.03 for L≤2 cm and αl=0.92±0.05 for L≥2 cm). The dynamical exponent, β, is measured to be 0.48±0.16. The role and range of hydrodynamic forces must be considered before this system can be related to available rough interface theories. A first attempt at assessing the effect of hydrodynamics yields a noise spectrum whose probability distribution is close to Gaussian (with significant excess of large fluctuations) and whose correlation function resembles that measured for density-density correlations in the oil far above the growing interface.

Technical Climate Change Adaptation Options of the Major Ski Resorts in Bulgaria

Climate change has been and increasingly will be a major threat to the ski tourism industry, whose survival is highly dependent on the existence of snow cover of sufficient depth and duration. For this matter, it is even now more usual for the ski resorts to adapt to this issue by various measures at the technical, operational, and political levels. Technically speaking, snowmaking has become the method most used throughout the industry to combat the immediate impacts of climate change, while moving the ski areas to higher terrains has been standing out as an another option, wherever available and feasible. In this study, the aim is to project the future climatic changes in snowmaking capacity; in other words, technical snow reliability, and the moving requirements, if any, of the four major ski resorts in Bulgaria for the period of 2016–2030 with respect to the control period of 1991–2005. For this purpose, the past and the future climatic conditions for the technical snow reliability of the ski resorts and their immediate surroundings are determined by the temperature and the relative humidity values generated and projected through the Regional Climate Model RegCM 4.4 of the Abdus Salam International Centre for Theoretical Physics (ICTP) by scaling the global climate model MPI-ESM-MR of Max Planck Institute for Meteorology down to a resolution of 10 km. The model is further processed according to the recent RCP 4.5 and RCP 8.5 concentration scenarios of the IPCC. The model outputs on air temperature and relative humidity are utilized for determination of wet-bulb temperatures through psychographic conversions that ultimately provide us with thresholds for snowmaking limits. Findings display the temporal changes in the snowmaking hours of the ski resorts at various altitudinal levels calculated according to the environmental lapse rates. Such displays can guide the practitioners in considering investment lives and moving the ski resorts according to optimistic and pessimistic projections.

Analysis of the Effect of Climate Change on the Yield of Crops in Turkey Using a Statistical Approach

In this study, simulation data set from ENSEMBLE project is used to set up a statistical model to estimate the yield of crops according to climatic variables and conditions. We chose fig as an example crop. Fig is grown around Aydin in Turkey. The number of days above 40°C between June and October, the number of days below −1°C between October and November, the mean of the maximum air temperature between June and September, the mean of minimum air temperature between October and November, annual total precipitation amount, annual mean of relative humidity and annual mean of cloud cover in that region are chosen as independent variables for multiple regression to estimate yield of fig for the period 1991–2000.

The Precipitation and Temperature Regime Over Three European Sub-regions as a Result of Climate Change

In this research, regional climate models’ (RCMs) simulation data set of PRUDENCE project is used to analyze the uncertainties, direction and magnitude of the expected changes of precipitation, temperature, maximum and minimum air temperature with two different scenarios (B2 and A2) in the period 2070–2100 and 1960–1990 for three different sub-regions of Europe (1.75°–15.75° East and 47.75°–55.75° North; 15.75°–25.75° East and 45.75°–55.75° North; 5.75°–13.75° East and 45.75°–47.75° North). SVM (support vector machine) is used to classify the models in order to choose the most appropriate ensembles with weighted coefficients from the multi model ensemble. The results are checked with ensemble-mean approach. In this study, we propose a new approach to multi-model ensemble. In general, the performance of our methodology is better than ensemble-mean approach. SVM can eliminate the models which have big amounts of absolute error and select the best ones that have small amounts of absolute error, with big coefficients. Moreover, our proposed methodology gives better results than ensemble-mean approach nearly in all cases.

THE EFFECT OF THE THIRD DIMENSION ON ROUGH SURFACES FORMED BY SEDIMENTING PARTICLES IN QUASI-TWO-DIMENSIONS

The roughness exponent of surfaces obtained by dispersing silica spheres into a quasi-two-dimensional cell is examined. The cell consists of two glass plates separated by a gap, which is comparable in size to the diameter of the beads. Previous work has shown that the quasi-one-dimensional surfaces formed have two roughness exponents in two length scales, which have a crossover length about 1 cm. We have studied the effect of changing the gap between the plates to a limit of about twice the diameter of the beads. If the conventional scaling analysis is performed, the roughness exponent is found to be robust against changes in the gap between the plates; however, the possibility that scaling does not hold should be taken seriously.