The Hasse norm principle in global function fields

Let $L$ be a finite extension of $\mathbb{F}_q(t)$. We calculate the proportion of polynomials of degree $d$ in $\mathbb{F}_q[t]$ that are everywhere locally norms from $L/\mathbb{F}_q(t)$ which fail to be global norms from $L/\mathbb{F}_q(t)$

Histopathologic and immunohistochemical investigations of dental abscess formed in maxillofacial area

Background: An abscess is a pocket of pus that forms around the root of an infected tooth. In this study, we aimed to investigate the extracellular matrix proteases ADAMTS1, ADAMTS4, osteonectin, and osteopontin expressions in abscess fluid cells in jaws after implantation and prosthesis operation. Materials and methods: In this clinical study, abscess fluids belonging to 17 patients who applied to the Department of Oral and Maxillofacial Surgery were examined histopathologically and immunohistochemically. In the histopathological examination of the abscess fluid, separation of chromatin bridges in the nuclei of neutrophil cells, pyknosis and apoptotic changes in the nucleus, degenerative change in the cytoplasm, and occasional vacuolar structures were observed. Results: The positive reaction of ADAMTS1 was observed in fibroblast cells, plasma cells, and macrophage cells. The positive reaction of ADAMTS4 was observed in fibroblast cells, osteoclast cells, and some apoptotic leukocyte cells. Osteopontin expression in osteoclastic cells and polymorphonuclear cells was defined as positive. Osteonectin expression was positive in polymorphonuclear leukocytes and hypertrophic fibroblast cells. Conclusions: ADAMTS1 and ADAMTS4 may induce bone destruction with its distinctive property in alveolar bone resorption, which promotes the activation of osteoclasts, which can accelerate the destruction of the extracellular matrix in the acute phase. Furthermore, osteoclastic activity increased with the increase of osteonectin and osteopontin protein expression due to inflammation in the abscess cases

Performance evaluation of LOS and NLOS vertical inhomogeneous links in underwater visible light communications

In this paper, underwater visible light communication (UWVLC) vertical links are modeled and evaluated, taking account of the inhomogeneous nature of underwater (UW) environment. An equivalent simplified model of stratified N layers is employed in which variations in refractive index and attenuation profiles across UW depth are considered. A generalized path loss expression is deduced which allows estimation of the vertical link loss prior to link design. Mathematical expressions of the received power for line-of-sight (LOS) and non-line-of-sight (NLOS) links between transmitters (Tx) and receivers are deduced. We evaluate the performance by computing the received power and bit error rate for inhomogeneous underwater links. Numerical examples are used to illustrate the proposed models. Deviations from expected results when considering a homogeneous underwater model are discussed. A simple underwater bilayer model is then introduced, which is considered a rough approximate model in comparison to the stratified N layers model. This model assists in estimating the UW link behavior without extensive calculations. The conditions necessary for applying this model are discussed and justified. Moreover, the effects of Tx orientation along with narrowing the transmitted light cone on LOS and NLOS vertical links are examined. A Tx power saving of 30%-50% in UWVLC links is proved to be achieved by rotating the Tx and narrowing its emitted light cone.NPRP award from the Qatar National Research Fund (Qatar Foundation)Publisher versio

Treatment Challenges in Pediatric Stroke Patients

Aim. In this study we presented our experience of 18 years on the etiology, risk factors, prophylactic and acute treatment, the effect of treatment to recurrence rate of patients with stroke. Methods. The population included 108 patients who had been treated for stroke at Pediatric Neurology Department of Ankara University with the diagnosis of arterial ischemic stroke and sinovenous thrombosis between January 1992 and August 2010. Forty-one girls (38%) and 67 boys (62%) with mean symptom age 3.1 ± 4.04 years, (0–18 years old) were followed up with a mean period of 4.9 ± 3.78 years (0–17 years). Results. 30 patients had no risk factors, 34 patients had only one risk factor and 44 patients had multiple risk factors. Recurrence was seen in three patients. There was no any statistical correlation between the recurrence of stroke and the existence of risk factors (P = .961). Seventeen patients received prophylactic treatment; 2 of them without any risk factors, 3 had one risk factor, 12 patients, who constituted the majority of our patients, had multiple risk factors (P = .024). Conclusion. With this study we showed that the right prophylaxis for right patients reduces the rate of recurrence

Application of Ion Implantation for Synthesis of Copper Nanoparticles in a Zinc Oxide Matrix for Obtaining New Nonlinear Optical Materials

We have obtained a layered composite material by implantation of single crystal zinc oxide (ZnO) substrates with 160-keV Cu+ ions to a dose of 10(16) or 10(17) cm(-2). The composite was studied by linear optical absorption spectroscopy; the nonlinear optical characteristics were determined by means of Z-scanning at a laser radiation wavelength of 532 nm. The appearance of the optical plasmon resonance bands in the spectra indicated that ion implantation to the higher dose provides for the formation of copper nanoparticles in a subsurface layer of ZnO. The new nonlinear optical material comprising metal nanoparticles in a ZnO matrix exhibits the phenomenon of self-defocusing and possesses a high nonlinear absorption coefficient (beta = 2.07 x 10(-3) cm/W). (C) 2004 MAIK "Nauka / Interperiodica"

Recent Developments and Characterization Techniques in 3D printing of Corneal Stroma Tissue

Corneal stroma has a significant function in normal visual function. The corneal stroma is vulnerable because of being the thickest part of the cornea, as it can be affected easily by infections or injuries. Any problems on corneal stroma can result in blindness. Donor shortage for corneal transplantation is one of the main issues in corneal transplantation. To address this issue, the corneal tissue engineering focuses on replacing injured tissues and repairing normal functions. Currently, there are no available, engineered corneal tissues for widely accepted routine clinical treatment, but new emerging 3D printing applications are being recognized as a promising option. Recent in vitro researches revealed that the biocompatibility and regeneration possessions of 3D-printed hydrogels outperformed conventional tissue engineering approaches. The goal of this review is to highlight the current developments in the characterization of 3D cell-free and bioprinted hydrogels

Nutrient recovery from anaerobically digested sewage sludge by struvite precipitation

Bu çalışmada, kentsel nitelikli anaerobik çürütülmüş çamurdan strüvit formunda nütrient geri kazanımı potansiyeli araştırılmıştır. Çürütülmüş çamurun katı fazından fosforun geri kazanımı için, katı faza fosfor çözündürme prosesinin uygulanması gerekmektedir. Çalışmada, çürütülmüş çamur katı fazına asidik koşullarda fosfor çözündürme prosesi uygulanması ile mevcut fosfor ortofosfata dönüştürülmüştür. Asidik koşullarda çözündürme prosesi ile oldukça yüksek nütrient içeriğine sahip (1085±4.95 mg/L NH3-N ve 840±21.21 mg/L PO4-P) fosforca zengin sıvı fazı elde edilmiştir. Asidik çözündürme prosesinin uygulanması ile katı fazdaki toplam fosforun yaklaşık %84’ü çözündürülmüştür. Fosfor çözündürme prosesinin strüvit çöktürmesi için başlangıç adımı olarak kullanılabileceği görülmüştür. Strüvit çöktürmesi testlerinde, Mg:N:P ve Mg:P molar oranlarının etkisi ayrı ayrı incelenmiştir. pH 8.5’da, Mg:N:P molar oranının 2:1:1.3 olduğu durumda PO4-P ve NH3-N giderim verimleri %99.84 ve 40.19 olarak elde edilmiştir. Bu durumda, strüvit çöktürmesi ile PO4-P’nin büyük bir kısmının NH4-N’nin ise belirli bir kısmının geri kazanımı gerçekleştirilmiştir. Asidik koşullarda çözündürme uygulaması sonucu fosforun yanı sıra serbest kalan metal iyonları, strüvit çöktürmesi sonucunda metal fosfatlar olarak çöktürülmüştür. Çalışmada, asidik çözündürme sonrası sıvı fazda mevcut bulunan Ca, Al, Fe ve Zn metallerinin yüksek konsantrasyonlarından dolayı, giderilen PO4-P’nin tamamı magnezyum amonyum fosfat olarak strüvit formunda giderilmemiştir. Bu durum strüvit katı fazında yapılan XRD analizi ile desteklenmiştir. XRD analizi sonucu, strüvite ek olarak diğer metal bileşiklerinin de mevcut olduğu görülmüştür. Anahtar Kelimeler: Fosfor çözündürülmesi, çürütülmüş çamur, nütrient geri kazanımı, strüvit çöktürmesi.The recovery of nutrients from the anaerobically digested waste stream is a potential source of revenue. There is an increasing awareness of limited natural resources and importance is given to the sustainable treatment activities; that is why control over the sources of N and P shifted from removal to recovery. This can be explained by the dependency of modern agriculture on P derived from phosphate rock. Phosphorus is an essential nutrient for all forms of life. Phosphorus consumption in the world in year 2006 was around 142 million tons of phosphate rock concentrate, which is annihilating economically extractable phosphate rocks. Therefore, the reliance on phosphate rocks should be stopped and sustainable ways to use phosphorus should be researched. A sustainable way to use phosphorus can be recovery of phosphorus from digested sewage sludge since almost all the removed phosphorus accumulates in treatment sludge in a conventional wastewater treatment plant whether phosphorus in wastewater is removed by biological phosphorus removal or by chemical phosphorus removal. Since mineral fertilizers account for approximately 80% of phosphates used worldwide, it would be beneficiary to recover phosphorus from digested sludge as a fertilizer. On the other hand, as a basic building block of plant protein; nitrogen is an essential element for agriculture and there is a growing demand for the nitrogenous fertilizer in the world. One of the most popular nutrient recovery applications in this sense is converting nutrients from digested sludge into magnesium ammonium phosphate hexahydrate (struvite). Struvite is a slow releasing fertilizer. Nutrient recovery from anaerobically digested sewage sludge is a viable option because digested sewage sludge is rich in nutrients. Moreover, most of the studies in literature focused on the removal/recovery of the readily available nutrients in the anaerobic digester effluents and little attempt were given on the extraction of the nutrients present in the solid phase of the anaerobic digester effluents. Therefore, this study focused on the removal and recovery of nutrients as struvite from solid phase effluents of a full-scale sewage sludge anaerobic digester. Nutrient recovery from the solid phase was achieved by the adoption of a novel phosphorus dissolution process. The recovery of nitrogen and phosphorus can only be done by using the dissolved fraction, but most of the nutrients are located in solid form. For this purpose, the solid phase was subjected to phosphorus dissolution process, thereby obtaining phosphorus-enriched liquid phase. The use of acidic phosphorus dissolution process was applicable to the solid phase of the full-scale sewage sludge anaerobic digester and can be used as a preliminary step of struvite precipitation experiments to obtain a nutrient rich solution. The dissolution of phosphorus from digested sludge consists of the following steps: Dissolution of the sludge using acids and separation of the phosphorus-enriched liquid phase from the remaining solid phase. The use of acidic phosphorus dissolution process led to the transformation of available phosphates into the orthophosphate. In this study the phosphorus-enriched liquid phase with considerably high concentrations of nutrients (1085±4.95 mg/L of NH3-N and 840±21.21 mg/L of PO4-P) was obtained. More than 80% phosphorus dissolution can be achieved at pH 2.0. In addition to the increase of orthophosphate concentration, acidic dissolution resulted in the release of the metals which were normally integrated in organic complex molecules into the liquid phase. Metals can be incorporated into the crystal lattice or sorbed to the surface of struvite. The phosphorus-enriched liquid phase was analyzed for the metals and heavy metals. In the struvite precipitation experiments conducted with the phosphorus-enriched liquid phase, the effects of molar concentration ratio of Mg:N:P and molar concentration ratio of Mg:P were investigated, separately. In the experiments conducted with the phosphorus-enriched liquid phase of digested sewage sludge by the addition of external phosphorus and magnesium, high recovery efficiencies (>99.7%) of PO4-P and partial recovery of (up to 40%) NH3-N was observed. Whereas in the experiments conducted by the addition of only magnesium, almost complete recovery (99.9%) of PO4-P and partial recovery of (only 5%) NH3-N was attained. The obtained results of the experiments indicated that struvite precipitation process can be used to recover PO4-P only or both NH3-N and PO4-P. The results from XRD analysis for the struvite precipitate collected from the reactor containing phosphorus-enriched solution indicated a struvite formation. Keywords: Phosphorus dissolution, digested sewage sludge, nutrient recovery, struvite precipitation

Scheduling Algorithms for Procrastinators

This paper presents scheduling algorithms for procrastinators, where the speed that a procrastinator executes a job increases as the due date approaches. We give optimal off-line scheduling policies for linearly increasing speed functions. We then explain the computational/numerical issues involved in implementing this policy. We next explore the online setting, showing that there exist adversaries that force any online scheduling policy to miss due dates. This impossibility result motivates the problem of minimizing the maximum interval stretch of any job; the interval stretch of a job is the job's flow time divided by the job's due date minus release time. We show that several common scheduling strategies, including the "hit-the-highest-nail" strategy beloved by procrastinators, have arbitrarily large maximum interval stretch. Then we give the "thrashing" scheduling policy and show that it is a \Theta(1) approximation algorithm for the maximum interval stretch.Comment: 12 pages, 3 figure