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Frustrated further-neighbor antiferromagnetic and electron-hopping interactions in the d=3 t-J model: finite-temperature global phase diagrams from renormalization group theory
No full textThe renormalization-group theory of the d=3 t-J model is extended to further-neighbor antiferromagnetic or electron-hopping interactions, including the ranges of frustration. The global phase diagram of each model is calculated for the entire ranges of temperatures, electron densities, further/first-neighbor interaction-strength ratios. With the inclusion of further-neighbor interactions, an extremely rich phase diagram structure is found and is explained by competing and frustrated interactions. In addition to the tau(tJ) phase seen in earlier studies of the nearest-neighbor d=3 t-J model, the tau(Hb) phase seen before in the d=3 Hubbard model appears both near and away from half filling
Quantum correlations and coherence in spin-1 Heisenberg chains
No full textWe explore quantum and classical correlations along with coherence in the ground states of spin-1 Heisenberg chains, namely the one-dimensional XXZ model and the one-dimensional bilinear biquadratic model, with the techniques of density matrix renormalization group theory. Exploiting the tools of quantum information theory, that is, by studying quantum discord, quantum mutual information, and three recently introduced coherence measures in the reduced density matrix of two nearest neighbor spins in the bulk, we investigate the quantum phase transitions and special symmetry points in these models. We point out the relative strengths and weaknesses of correlation and coherence measures as figures of merit to witness the quantum phase transitions and symmetry points in the considered spin-1 Heisenberg chains. In particular, we demonstrate that, as none of the studied measures can detect the infinite-order Kosterlitz-Thouless transition in the XXZ model, they appear to be able to signal the existence of the same type of transition in the biliear biquadratic model. However, we argue that what is actually detected by the measures here is the SU(3) symmetry point of the model rather than the infinite-order quantum phase transition. Moreover, we show in the XXZ model that examining even single site coherence can be sufficient to spotlight the second-order phase transition and the SU(2) symmetry point
DNA barcoding of birds at a migratory hotspot in Eastern Turkey highlights continental phylogeographic relationships
No full textThe combination of habitat loss, climate change, direct persecution, introduced species and other components of the global environmental crisis has resulted in a rapid loss of biodiversity, including species, population and genetic diversity. Birds, which inhabit a wide spectrum of different habitat types, are particularly sensitive to and indicative of environmental changes. The Caucasus endemic bird area, part of which covers northeastern Turkey, is one of the world's key regions harboring a unique bird community threatened with habitat loss. More than 75% of all bird species native to Turkey have been recorded in this region, in particular along the Kars-Igdir migratory corridor, stopover, wintering and breeding sites along the Aras River, whose wetlands harbor at least 264 bird species. In this study, DNA barcoding technique was used for evaluating the genetic diversity of land bird species of Aras River Bird Paradise at the confluence of Aras River and Igdir Plains key biodiversity areas. Seventy three COI sequences from 33 common species and 26 different genera were newly generated and used along with 301 sequences that were retrieved from the Barcoding of Life Database (BOLD). Using the sequences obtained in this study, we made global phylogeographic comparisons to define four categories of species, based on barcoding suitability, intraspecific divergence and taxonomy. Our findings indicate that the landbird community of northeastern Turkey has a genetical signature mostly typical of northern Palearctic bird communities while harboring some unique variations. The study also provides a good example of how DNA barcoding can build upon its primary mission of species identification and use available data to integrate genetic variation investigated at the local scale into a global framework. However, the rich bird community of the Aras River wetlands is highly threatened with the imminent construction of the Tuzluca Dam by the government
Cross-linguistic patterns in the acquisition of quantifiers
No full textLearners of most languages are faced with the task of acquiring words to talk about number and quantity. Much is known about the order of acquisition of number words as well as the cognitive and perceptual systems and cultural practices that shape it. Substantially less is known about the acquisition of quantifiers. Here, we consider the extent to which systems and practices that support number word acquisition can be applied to quantifier acquisition and conclude that the two domains are largely distinct in this respect. Consequently, we hypothesize that the acquisition of quantifiers is constrained by a set of factors related to each quantifier's specific meaning. We investigate competence with the expressions for "all," "none," "some," "some. not," and "most" in 31 languages, representing 11 language types, by testing 768 5-y-old children and 536 adults. We found a cross-linguistically similar order of acquisition of quantifiers, explicable in terms of four factors relating to their meaning and use. In addition, exploratory analyses reveal that language-and learner-specific factors, such as negative concord and gender, are significant predictors of variation
A missed Behçet’s case presenting with spontaneous epidural hematoma
No full textSpinal vascular events related to Behçet's disease are relatively uncommon. Deep vein thrombosis is the most frequent vascular involvement. Anticoagulant therapy is a debated issue in Behçet's disease. In this case report, we present a patient with a delayed diagnosis of Behçet's disease after development of cervical epidural hematoma following anticoagulant therapy due to deep venous thrombosis. Anticoagulant therapy without immunosuppressive therapy leading to uncontrolled systemic inflammation may be the cause of spinal epidural hematoma. On the other hand, epidural vascular involvement as a vasculitic manifestation of Behçet's disease in conjunction with anticoagulant therapy may have predisposed to spontaneous bleeding via increased fragility or microaneurysms in epidural arteries. In this case report, the importance of a multidisciplinary approach to Behçet's disease is emphasized
Adaptive reference levels in a level-crossing analog-to-digital converter
No full textLevel-crossing analog-to-digital converters (LC ADCs) have been considered in the literature and have been shown to efficiently sample certain classes of signals. One important aspect of their implementation is the placement of reference levels in the converter. The levels need to be appropriately located within the input dynamic range, in order to obtain samples efficiently. In this paper, we study optimization of the performance of such an LC ADC by providing several sequential algorithms that adaptively update the ADC reference levels. The accompanying performance analysis and simulation results show that as the signal length grows, the performance of the sequential algorithms asymptotically approaches that of the best choice that could only have been chosen in hindsight within a family of possible schemes
Renyi divergences, Bures geometry and quantum statistical thermodynamics
No full textThe Bures geometry of quantum statistical thermodynamics at thermal equilibrium is investigated by introducing the connections between the Bures angle and the Renyi 1/2-divergence. Fundamental relations concerning free energy, moments of work, and distance are established
Potential of serum and urinary matrix metalloproteinase-9 levels for the early detection of renal involvement in children with henoch-schonlein purpura
No full textBackground: Matrix metalloproteinase-9 (MMP-9) is an enzyme implicated in the pathogenesis of renal diseases. Renal involvement is the principal cause of morbidity and mortality in children with Henoch-Schonlein purpura (HSP). Objectives: The aim of this study was to evaluate whether serum and urinary MMP-9 levels are associated with renal involvement in HSP Patients and Methods: We evaluated 40 children with HSP (patient group) and 27 healthy volunteer children (control group). The patient group was divided into two subgroups based on the presence or absence of nephritis. Nephritis was defined as the existence of hematuria and/or proteinuria. All anthropometric data, physical examination findings, blood pressure, and laboratory parameters were recorded. The serum and urine samples were analyzed to determine the MMP-9 levels three days after the initial phase of the disease. Results: The mean age was 7.65 +/- 3.41 (range 2-16) years in the patient group and 9.52 +/- 3.91 (range 2-16) years in the control group. Henoch-Schonlein purpura nephritis (HSPN) was identified in eight patients. There was no significant difference in the serum MMP-9 levels between the HSPN subgroup and the controls (P > 0.05). However, there were significant differences in the urinary MMP-9 levels between the HSP subgroup and the control group (P < 0.05), with the urinary MMP-9 levels being significantly higher in patients in the HSP subgroup (P = 0.001). Further, the urinary MMP-9 levels were significantly higher in the patients with nephritis than in the patients without nephritis (P = 0.001) and the controls (P = 0.001). The optimal cut-off point (sensitivity; specificity) of the urinary MMP-9 level for the diagnosis of HSPN was 94.7 pg/mL. Conclusions: The levels of MMP-9 in the urine were remarkably high in patients with HSPN. This non-invasive marker may the refore be an important indicator for the early diagnosis of nephritis in children with HSP
Wavelength selection in measuring red blood cell aggregation based on light transmittance
No full textThe reversible aggregation of red blood cells (RBC) is of current basic science and clinical interest. Using a flow channel and light transmittance (LT) through RBC suspensions, we have examined the effects of wavelength (500 to 900 nm) on the static and dynamic aspects of RBC aggregation for normal blood and suspensions with reduced or enhanced aggregation; the effects of oxygenation were also explored. Salient observations include: 1. significant effects of wavelength on aggregation parameters reflecting the extent of aggregation (i.e., number of RBC per aggregate); 2. no significant effects of wavelength on parameters reflecting the time course of RBC aggregation; 3. a prominent influence of hemoglobin oxygen saturation on both extent and time-course related aggregation parameters measured at wavelengths less than 700 nm, but only on the time-course at 800 nm; and 4. the power of parameters in detecting a given alteration of RBC aggregation is affected by wavelength, in general being greater at higher wavelengths. It is recommended that light sources with wavelengths around 800 nm be used in instruments for measuring RBC aggregation via LT
Spectral self-interference fluorescence microscopy
No full textSpontaneous emission of fluorophores located close to a reflecting surface is modified by the interference between direct and reflected waves. The spectral patterns of fluorescent emission near reflecting surfaces can be precisely described with a classical model that considers the relative intensity and polarization state of direct and reflected waves depending on dipole orientation. An algorithm based on the emission model and polynomial fitting built into a software application can be used for fast and efficient analysis of self-interference spectra, yielding information about the location of the emitters with subnanometer precision. Spectral information was used to study thin films of fluorescent substances on surfaces