Weak phase stiffness and mass divergence of superfluid in underdoped cuprates

Despite more than two decades of intensive investigations, the true nature of high temperature (high-$T_c$) superconductivity observed in the cuprates remains elusive to the researchers. In particular, in the so-called `underdoped' region, the overall behavior of superconductivity deviates $qualitatively$ from the standard theoretical description pioneered by Bardeen, Cooper and Schrieffer (BCS). Recently, the importance of phase fluctuation of the superconducting order parameter has gained significant support from various experiments. However, the microscopic mechanism responsible for the surprisingly soft phase remains one of the most important unsolved puzzles. Here, opposite to the standard BCS starting point, we propose a simple, solvable low-energy model in the strong coupling limit, which maps the superconductivity literally into a well-understood physics of superfluid in a special dilute bosonic system of local pairs of doped holes. In the prototypical material (La$_{1-\delta}$Sr$_\delta$)$_2$CuO$_4$, without use of any free parameter, a $d$-wave superconductivity is obtained for doping above $\sim 5.2\%$, below which unexpected incoherent $p$-wave pairs dominate. Throughout the whole underdoped region, very soft phases are found to originate from enormous mass enhancement of the pairs. Furthermore, a striking mass divergence is predicted that dictates the occurrence of the observed quantum critical point. Our model produces properties of the superfluid in good agreement with the experiments, and provides new insights into several current puzzles. Owing to its simplicity, this model offers a paradigm of great value in answering the long-standing challenges in underdoped cuprates

Turkish migrant workers in the Federal Republic of Germany : an anthropological study of migration.

SIGLEAvailable from British Library Document Supply Centre- DSC:D42308/82 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Evaluating a mesoscale atmosphere model and a satellite-based algorithm in estimating extreme rainfall events in northwestern Turkey

Quantitative precipitation estimates are obtained with more uncertainty under the influence of changing climate variability and complex topography from numerical weather prediction (NWP) models. On the other hand, hydrologic model simulations depend heavily on the availability of reliable precipitation estimates. Difficulties in estimating precipitation impose an important limitation on the possibility and reliability of hydrologic forecasting and early warning systems. This study examines the performance of the Weather Research and Forecasting (WRF) model and the Multi Precipitation Estimates (MPE) algorithm in producing the temporal and spatial characteristics of the number of extreme precipitation events observed in the western Black Sea region of Turkey. Precipitation derived from WRF model with and without the three-dimensional variational (3DVAR) data assimilation scheme and MPE algorithm at high spatial resolution (5 km) are compared with gauge precipitation. WRF-derived precipitation showed capabilities in capturing the timing of precipitation extremes and to some extent the spatial distribution and magnitude of the heavy rainfall events, whereas MPE showed relatively weak skills in these aspects. WRF skills in estimating such precipitation characteristics are enhanced with the application of the 3DVAR scheme. Direct impact of data assimilation on WRF precipitation reached up to 12% and at some points there is a quantitative match for heavy rainfall events, which are critical for hydrological forecasts

Watermarking via zero assigned filter banks

Cataloged from PDF version of article.In order to identify the owner and distributor of digital data, a watermarking scheme in frequency domain for multimedia files is proposed. The scheme satisfies the imperceptibility and persistence requirements and it is robust against additive noise. It consists of a few stages of wavelet decomposition of several subblocks of the original signal using special zero assigned filter banks. By assigning zeros to filters on the high frequency portion of the spectrum, filter banks with frequency selective response are obtained. The information is then inserted in the wavelet-decomposed and compressed signal. Several robustness tests are performed on male voice, female voice, and music files, color and gray level images. The algorithm is tested under white Gaussian noise and against JPEG compression and it is observed to be robust even when exposed to high levels of corruption. & 2009 Elsevier B.V. All rights reserve

Work-family conflict and partners' agreement on fertility preferences among dual-earner couples: Does women's employment status matter?

Objective: This study tests the effects of work-family conflict, in both directions, on partners' agreement on fertility preferences among dual-earner couples, as well as whether this relationship varies by women's employment status. Background: Few studies have examined the relationship between work-family conflict and fertility preferences. Given the high percentages of women working part-time in Germany, it is important to investigate the role working women’s employment status plays to further understand this relationship. Method: Using data from 716 dual-earner couples in Wave 10 of the German Family Panel (pairfam), we use dyadic data analysis to test whether work-family conflict impacts one’s own ("actor effects") and/or one’s partner’s ("partner effects") reports of agreement on fertility preferences. We also run multi-group analyses to compare whether these effects vary in "full-time dual-earner" versus "modernized male breadwinner" couples. Results: There are significant actor effects for family-to-work conflict in both types of couples, and for work-to-family conflict in modernized male breadwinner couples only. Partner effects for family-to-work conflict exist only among modernized male breadwinner couples. While there are no gender differences in actor or partner effects, results suggest differences in the partner effect (for family-to-work conflict only) between these two couple types. Conclusion: These findings indicate that work-family conflict is associated with greater partner disagreement on fertility preferences and highlight the differential impact incompatible work and family responsibilities have on fertility decisions when women work full-time versus part-time.Fragestellung: Die Studie untersucht die Auswirkungen des work-family conflict auf die Einigkeit der Partner im Hinblick auf die Anzahl gemeinsamer Kinder in Doppelverdiener-Paaren und ob dieser Zusammenhang vom Erwerbsstatus der Frau abhängt. Hintergrund: Der Zusammenhang zwischen work-family conflict und dem Kinderwunsch wurde bisher kaum untersucht. Da ein hoher Anteil der Frauen in Deutschland teilzeitbeschäftigt ist, sollte der Erwerbsstatus von Frauen berücksichtigt werden, um den Zusammenhang besser zu verstehen. Methode: Mit dyadischen Analysen wurde für 716 Doppelverdiener-Paare aus der 10. Welle des Beziehungs- und Familienpanels (pairfam) untersucht, inwiefern der work-family conflict sich auf die eigene („Akteureffekt“) Bewertung und/oder auf die des Partners ("Partnereffekt") bezüglich der Einigkeit im Hinblick auf die Anzahl der gewünschten Kinder auswirkt. Mit einer Mehrgruppenanalyse wurde außerdem untersucht, ob sich diese Effekte unterscheiden zwischen Paaren, in denen beide Partner in Vollzeit arbeiten und Paaren, in denen der Mann in Vollzeit und die Frau in Teilzeit arbeitet. Ergebnisse: Für beide Paarformen gibt es signifikante Akteurseffekte des family-to-work conflict, des work-to-family conflict jedoch nur bei Paaren des modernisierten Ernährermodells. Partnereffekte von family-to-work conflict lassen sich nur in den Paaren des modernisierten Ernährermodells identifizieren. Während es keine Geschlechterunterschiede in Akteurs- oder Partnereffekten gibt, deuten die Ergebnisse auf Unterschiede im Partner-Effekt (nur für family-to-work conflict) zwischen den beiden Paarformen an. Schlussfolgerung: Die Ergebnisse zeigen, dass work-family conflict mit Unterschieden zwischen Partnern bezüglich der gewünschten Kinderanzahl zusammenhängen und dass die widersprüchlichen Anforderungen zwischen Arbeit und Familienleben sich auf den Kinderwunsch auswirkt, wenn Frauen in Vollzeit statt Teilzeit arbeiten

Contribution of speckle noise in near-infrared spectroscopy measurements

Near-infrared spectroscopy (NIRS) is widely used in biomedical optics with applications ranging from basic science, such as in functional neuroimaging, to clinical, as in pulse oximetry. Despite the relatively low absorption of tissue in the near-infrared, there is still a significant amount of optical attenuation produced by the highly scattering nature of tissue. Because of this, designers of NIRS systems have to balance source optical power and source–detector separation to maximize the signal-to-noise ratio (SNR). However, theoretical estimations of SNR neglect the effects of speckle. Speckle manifests as fluctuations of the optical power received at the detector. These fluctuations are caused by interference of the multiple random paths taken by photons in tissue. We present a model for the NIRS SNR that includes the effects of speckle. We performed experimental validations with a NIRS system to show that it agrees with our model. Additionally, we performed computer simulations based on the model to estimate the contribution of speckle noise for different collection areas and source–detector separations. We show that at short source–detector separation, speckle contributes most of the noise when using long coherence length sources. Considering this additional noise is especially important for hybrid applications that use NIRS and speckle contrast simultaneously, such as in diffuse correlation spectroscopy.R01 EB025145 - NIBIB NIH HHS; R24 NS104096 - NINDS NIH HHSPublished versio

Recent Ferroalloy Studies at Istanbul Technical University

The present report is the summary of the experimental studies on the production of ferroalloys and iron-based alloys, which have been conducted in the laboratories of Macro to Nano Research Team (MtNT, Yücel’s Group) at Istanbul Technical University (ITU, Turkey) – Metallurgical and Materials Engineering Department in the last decade. Ferromolybdenum, ferrochromium, ferronickel, and iron-based alloys with alloying elements (Mo, Ni, Cr, etc.) were produced through different reduction processes (metallothermic and carbothermic) starting from different reactant materials such as mill scale, hematite, magnetite, NiO, Cr2O3, chromic acid, and MoO3. The effects of different stoichiometric amounts of reactants and reductant powders were investigated for the production of unalloyed Fe. While, different amounts of metal oxide ratios and their effects on metal recoveries, compositions, and microstructure of final alloys were studied during Fe-based alloys production, raw materials and produced alloys and slags were characterized by using chemical analysis methods (AAS, ICP), X-ray diffraction spectrometry (XRD), X-ray fluorescence spectrometry (XRF), and scanning electron microscopy (SEM/EDS) techniques. Keywords: iron-based alloys, carbothermic reduction, metallothermic reduction, İT