Images delegitimized and discouraged: explicitly political art and the arbitrariness of the unspeakable

While the increasing interest in contemporary art from Turkey has centered on explicitly political works, discussions on the limitations of the freedom of expression have likewise come under the spotlight, not least with regard to Turkey's EU candidacy. In contrast to the attempts of complete suppression marking the 1980 coup d'etat and its aftermath, current censorship mechanisms aim to delegitimize and discourage artistic expressions (and their circulation) that can be construed as threatening the territorial integrity and sovereignty of the Turkish state, and to turn their producers into targets. This article investigates selected images produced in the contemporary art world between 2005 and 2008, which were taken to transcend the limits of what constitutes tolerable depictions of Turkey's socio-political realities. It examines current modalities of censorship in the visual arts and the different actors involved in silencing efforts. The cases show that within these fields of delimitation there are considerable contingencies: The domain of the unspeakable remains unclearly mapped. I argue that it is because, not despite, this arbitrariness that delegitimizing interventions are successful, in that they (a) create incentives for self-censorship, and (b) produce defenses of artistic freedom that, by highlighting the autonomy of art, to some extent consolidate a conceptual separation of art from politics

Quantification of methane fluxes and authigenic carbonate formation at cold seeps along the continental margin offshore Costa Rica: A numerical modeling approach

The expulsion of liquids, gases and fluids at continental margins covers a wide range of processes including not only mud volcanism, mud diapirism and gas flares, but also continuously seeping methane-rich fluids leading to cold vent sites and even outbursts of over-pressured gases. Seepage of fluids frequently leads to precipitation of authigenic carbonates that modify sedimentary processes along the margin, and finally, the fluids constitute the energy source for a number of diverse and complex ecosystems. During the last two decades, researchers gained significant knowledge about the impact of fluid seepage on local ecosystems and the biogeochemical processes that result in carbonate formation via the anaerobic oxidation of methane (AOM). However, all the knowledge was gained in different areas and geological settings of the world ocean but left a regional gap in our knowledge about seeps at the continental margin offshore Costa Rica. Those processes including authigenic carbonate precipitation, quantification of the impact of fluid seepage and methane budgets are documented in the present thesis. Chapter II presents comprehensive results from five cold seep structures at the Costa Rican continental margin addressing the relationship between fluid advection, dissolved calcium concentrations in upward migrating fluids, and authigenic calcium carbonate precipitation. A numerical transport-reaction model was used to determine rates of AOM, CaCO3 precipitation, and benthic fluxes of solutes. Production of carbonate alkalinity and formation of authigenic carbonates is most intense at intermediate flow rates (3-40 cm a-1) and reduced under low and high flux conditions (0.1 and 200 cm a-1). Systematic model runs showed that high Ca concentrations in ascending fluids enhance the rate of authigenic carbonate production at moderate flow rates leading to an almost quantitative fixation of deeply derived Ca in authigenic carbonates. Hence, CaCO3 precipitation is not only controlled by Ca diffusing into the sediment from bottom water, but also by the Ca concentration in ascending fluids. Based on average precipitation rates deduced from the systematic model runs the global Ca-fixation at cold seeps (~2·1010 mol Ca a-1) suggesting that cold seeps are most likely not of key importance with respect to Ca cycling in the ocean. Chapter 3 comprises the quantitative estimates of dissolved methane discharge from wellstudied mud mounds (Mound 11 and Mound 12) at the submarine section of the Costa Rica fore-arc combining geochemical and geoacoustic data. The study is supported by 75 kHz sidescan sonar data, pore-water analysis and visual sea-floor observations by remotely operated vehicle (ROV). A numerical transport reaction model was applied to determine dissolved methane fluxes considering AOM and upward fluid flow. Model results reveal that a significant portion of methane from greater depth is discharged into the bottom water only at high fluid flow velocities that are not sufficiently moderate to allow for AOM. The overall amount of dissolved methane released from the entire mud mounds into the water column was moderate with a discharge of 0.36·106 mol a-1 at Mound 11 whereas it was calculated as 0.58·106 mol a-1 at Mound 12. Compared to other active cold seeps (mainly mud volcanoes), mud mounds at the submarine section of the Costa Rica fore arc do not represent a pathway for significant methane discharge from the seafloor. Sea floor methane emissions from bacterial mat sites of a submarine slide at the Costa Rica continental margin are presented in Chapter IV. The estimates of methane fluxes into the water column are based on (i) detailed mapping in order to determine the abundance of seeps, and thus the spatial validity of the flux measurements; and (ii) application of numerical model to estimate the amount of methane that is transported into the bottom water. Model results illustrate that the majority of the studied seeps transport rather limited amount of methane into the water column due to medium to low advection rates (average 10 cm a-1 ) allowing high methane consumption by AOM (average 45%) and limiting the methane discharge into the water column. Depth-integrated AOM rates (56-1538 μmol CH4 cm-2 a-1) are comparable with the values reported at other very active vents sites, suggesting that the Quepos Slide should be regarded as one of the most active sites at the seafloor. The overall amount of dissolved methane released from the entire bacterial mat sites into the water column is determined as 0.56·106 mol a-1. This conservative estimate, relying on rather accurate determinations of sea floor methane fluxes out of bacterial mats emphasizes the importance of submarine slides as sites of natural methane seepage

The impact of foreign players on international football performance

I investigate the impact of foreign players on international football performance of club teams and national teams in this paper. My empirical findings show that foreign players have a positive effect on club teams’ international performance. Howewer, foreign players don’t have any effect on performance of national teams.Football; Foreign players

Load-aware Channel Selection for 802.11 WLANs with Limited Measurement

It has been known that load unaware channel selection in 802.11 networks results in high level interference, and can significantly reduce the network throughput. In current implementation, the only way to determine the traffic load on a channel is to measure that channel for a certain duration of time. Therefore, in order to find the best channel with the minimum load all channels have to be measured, which is costly and can cause unacceptable communication interruptions between the AP and the stations. In this paper, we propose a learning based approach which aims to find the channel with the minimum load by measuring only limited number of channels. Our method uses Gaussian Process Regressing to accurately track the traffic load on each channel based on the previous measured load. We confirm the performance of our algorithm by using experimental data, and show that the time consumed for the load measurement can be reduced up to 46% compared to the case where all channels are monitored.Comment: accepted to IC

Exploiting Weak Supermodularity for Coalition-Proof Mechanisms

Under the incentive-compatible Vickrey-Clarke-Groves mechanism, coalitions of participants can influence the auction outcome to obtain higher collective profit. These manipulations were proven to be eliminated if and only if the market objective is supermodular. Nevertheless, several auctions do not satisfy the stringent conditions for supermodularity. These auctions include electricity markets, which are the main motivation of our study. To characterize nonsupermodular functions, we introduce the supermodularity ratio and the weak supermodularity. We show that these concepts provide us with tight bounds on the profitability of collusion and shill bidding. We then derive an analytical lower bound on the supermodularity ratio. Our results are verified with case studies based on the IEEE test systems

Approaching Optimal Centralized Scheduling with CSMA-based Random Access over Fading Channels

Carrier Sense Multiple Access (CSMA) based distributed algorithms can attain the largest capacity region as the centralized Max-Weight policy does. Despite their capability of achieving throughput-optimality, these algorithms can either incur large delay and have large complexity or only operate over non-fading channels. In this letter, by assuming arbitrary back-off time we first propose a fully distributed randomized algorithm whose performance can be pushed to the performance of the centralized Max-Weight policy not only in terms of throughput but also in terms of delay for completely-connected interference networks with fading channels. Then, inspired by the proposed algorithm we introduce an implementable distributed algorithm for practical networks with a reservation scheme. We show that the proposed practical algorithm can still achieve the performance of the centralized Max-Weight policy.Comment: accepted to IEEE Communications Letter

A new record of zerconid mites (Acari, Mesostigmata, Zerconidae) from the Thrace region of Turkey

In this study, Prozercon martae Ujvári, 2010 is recorded for the first time from Turkey. On the basis of the samples collected from the Thrace region of Turkey, its morphological features are given with drawings. © TÜBITAK

An Open Inflationary Model for Dimensional Reduction and its Effects on the Observable Parameters of the Universe

Assuming that higher dimensions existed in the early stages of the universe where the evolution was inflationary, we construct an open, singularity-free, spatially homogeneous and isotropic cosmological model to study the effects of dimensional reduction that may have taken place during the early stages of the universe. We consider dimensional reduction to take place in a stepwise manner and interpret each step as a phase transition. By imposing suitable boundary conditions we trace their effects on the present day parameters of the universe.Comment: 5 pages, accepted for publication in Int. J. of Mod. Phys.