Non-relativistic Lee Model on two Dimensional Riemannian Manifolds

This work is a continuation of our previous work (JMP, Vol. 48, 12, pp. 122103-1-122103-20, 2007), where we constructed the non-relativistic Lee model in three dimensional Riemannian manifolds. Here we renormalize the two dimensional version by using the same methods and the results are shortly given since the calculations are basically the same as in the three dimensional model. We also show that the ground state energy is bounded from below due to the upper bound of the heat kernel for compact and Cartan-Hadamard manifolds. In contrast to the construction of the model and the proof of the lower bound of the ground state energy, the mean field approximation to the two dimensional model is not similar to the one in three dimensions and it requires a deeper analysis, which is the main result of this paper.Comment: 18 pages, no figure

Influence of cadmium and copper on tissue element levels of pregnant rats

In the current study, we examined the effects of Cd on Cd, Cu, Zn and Fe levels in placenta and maternal and fetal plasma and tissues, the placental weight, total fetal and maternal body weights, and fetal and maternal tissue weights during pregnancy. A total of 21 adult female rats were treated during gestation with drinking water containing one of the following: 70 mg/L of CdCl2, a combination of 70 mg/L of CdCl2 and 70 mg/L of CuSO4, or no addition (control). Placenta Cu and Fe levels, fetal liver and kidney Cu levels, and fetal liver tissue weights were lower in the group administered Cd than in the control group. Also, Cd levels in the placenta, maternal and fetal liver, and maternal kidney were higher in the group treated with Cd than in controls. In the group administered both Cd and Cu, fetal body and tissue weights did not change, but Cd levels in the placenta, maternal and fetal liver, and maternal kidneys were higher than in controls. Zn and Fe levels in the maternal kidney and fetal liver were also lower in this group. Cd exposure during pregnancy resulted in Cd accumulation in maternal and fetal tissues during pregnancy and a decrease in the total weight of fetuses, and the combination of Cd and Cu caused some changes in the both maternal and fetal levels of Cu, Zn, and Fe, but it did not cause changes in the total fetal body weight or the weights of individual tissues. © 2007 Versita Warsaw and Springer-Verlag

Supergrassmannian and large N limit of quantum field theory with bosons and fermions

We study a large N_{c} limit of a two-dimensional Yang-Mills theory coupled to bosons and fermions in the fundamental representation. Extending an approach due to Rajeev we show that the limiting theory can be described as a classical Hamiltonian system whose phase space is an infinite-dimensional supergrassmannian. The linear approximation to the equations of motion and the constraint yields the 't Hooft equations for the mesonic spectrum. Two other approximation schemes to the exact equations are discussed.Comment: 24 pages, Latex; v.3 appendix added, typos corrected, to appear in JM

Effects of chemical composition and B2 order on phonons in bcc Fe–Co alloys

The phonon density of states (DOS) gives insight into interatomic forces and provides the vibrational entropy, making it a key thermodynamic function for understanding alloy phase transformations. Nuclear resonant inelastic x-ray scattering and inelastic neutron scattering were used to measure the chemical dependence of the DOS of bcc Fe–Co alloys. For the equiatomic alloy, the A2→B2 (chemically disordered→chemically ordered) phase transformation caused measurable changes in the phonon spectrum. The measured change in vibrational entropy upon ordering was −0.02±0.02 k_B/atom, suggesting that vibrational entropy results in a reduction in the order–disorder transition temperature by 60±60 K. The Connolly–Williams cluster inversion method was used to obtain interaction DOS (IDOS) curves that show how point and pair variables altered the phonon DOS of disordered bcc Fe–Co alloys. These IDOS curves accurately captured the change in the phonon DOS and vibrational entropy of the B2 ordering transition

Tarihî kentsel alanlarda “toplumsal ve mekânsal yeniden yapılanma”: Fener ve Balat örneği

Dünya sosyo-kültürel, fiziksel, ekonomik, politik ve teknolojik dinamikler çerçevesinde değişmekte, kentsel alanlar da bu değişimin yansıdığı mekânlar olarak karşımıza çıkmaktadır. Bu dinamiklerin karşılıklı etkileşimi ile şekillenen kent mekânı, her çağda, her ülkede ve her şehirde bazı benzerlikler ve farklılıklar içermektedir. Bu nedenle de hiçbir şehir bir diğerinin aynı olarak şekillenmemektedir. Buna rağmen, belli başlı olaylar çerçevesinde dünya üzerindeki tüm şehirler genel olarak, benzer şekilde etkilenmiştir.publisher versio

Assessment of spatial distribution patterns of soil properties in the EAARI-Experimental Station (Erzurum)

Defining spatial distribution patterns of soil properties within a field or watershed is important for site-specific soil and plant management. The objective of this study was to determine spatial distribution patterns of particle size distribution, organic matter, lime content, pH and plant-available P contents of soils in the Experimental Station of the Eastern Anatolia Agricultural Research Institution (EAARI). The research area, about 100 ha, was gridded with 100 m intervals in the north to south and east to west directions, and 68 soils samples were collected from 0-20 cm dept at each intersection. Exponential semivariogram models were fitted for clay, silt and sand contents and soil pH, Gaussion models for lime content and plant-available P, and spherical model for organic matter content. Block kriging analysis was performed to prepare distribution maps. Distribution patterns of soil properties studied showed great similarities with each other, as the patterns of yield

Dağınık kontrol sistemleri için bir ağ tasarımı

In this study, modular, scalable and flexible control system architecture around a serial communication bus is proposed to fulfill control tasks. This bus is named K-Bus. One of the differentiating features of the proposed architecture is its capability to access different data on distributed modules in a single network transaction. Accessing multiple modules in a single transaction can be achieved both while data writing and data reading. Second differentiating feature of K-Bus is its capability to access predefined data without using module or data addresses. Network data collision avoidance is obtained by adding hardware components around RS?485 electrical layer to detect and avoid data collision. Package priorities are obtained with sender's identification number in the protocol, which is also used by the hardware layer to decide the winner in case of a collision. Two timer based locks are provided by the hardware layer blocks accessing to the bus during a transaction. One of the timers measures the time to end a whole transaction, while other timer keeps the time between different module or data cycles within the transaction. Modules replying to a high priority master will be able to produce their response in the same package cycle, without the need to wait for the next available slot. This allows high priority master modules to rapidly access to low priority modules within master module's priority. This feature enables predictable access times to resources in multi mastered networks. K-Bus also allows acknowledgement to be transferred in a single network transaction. High real time performance and relatively less processor resource consumption are key design requirements. Signals between K-Bus hardware and microprocessor are designed to allow interrupt driven software for network interfacing. Hardware layer is designed to transfer minimal load to the processor. It is capable of blocking interrupts to the processor for data packages that are not targeted to processor's module. An analyze have been performed to show that, in the given example, using hardware provided method to block interrupts for a transaction that does not involve the module would reduce the protocol related CPU load from 18.75% to 3%. Proposed architecture enables K-Bus to be used in different applications with variety of modules. K-Bus has following properties: different data from multiple modules can be accessed in a single transaction; multiple master modules can be present on the same data bus; hardware priority is given for data packages; data package collisions are detected at hardware level; erroneous or collided data packages are automatically resend by software; one data package can be broadcasted to more than one module; by the help of standard data concept, fundamental parameters can be reached without using module address; by the help of block data transfer, more than one data can be transferred in single K-Bus package and the overhead coming from package structure is reduced. The paper is organized as follows: first the underlying electrical layer of K-Bus, RS-485, is briefly compared to other real-time network electrical layers. In the following section, logical components of K-Bus are described. These are given in Figures 1 and 2. An analysis is done in this section to demonstrate the CPU savings using K-Bus?s interrupt disabling capability for packages that are not targeted to a module. In the next section a sample read package was shown in Figure 3. This sample read package demonstrates interrupt blocking capability and multiple data read capability. All K-bus packages have 9 fields: sender's identification, SID; receiver's identification, RID; command, CMD; package length, LEN; data fields DTA; optional acknowledge or not acknowledge, ACK/NAK; optional command data, CD; checksum CSM; and end of package, EOF. All K-Bus fields, sections except DTA, are of fixed length of 1 byte. Figure 3 shows all the sections except optional ACK/NAK. All K-Bus protocols start with sender identifier (SID) field. This field is used by the hardware layer to determine the priority of the sender. In case of data collision this field is used to decide the winner. Figure 3 also shows two hardware timers, HM and HM2, which are used to control transaction. In the later section a detailed electrical design of the given K-Bus interface is given and is shown in Figure 4. Last section discusses trade off of performance for real time capabilities in K-Bus design. Keywords: Real-time buses, distributed control systems, unmanned aerial vehicles.Bu çalışmada, K-Bus olarak adlandırılan bir seri iletişim yolu çevresinde ölçeklenebilir, esnek ve modüler bir kontrol mimarisi önerilmiştir. RS–485 elektrik seviyesine donanım ilavesi yapılarak güvenli ve yazılım yükü çok olmayan veri çarpışma önleme sistemi kurulmuştur. Verilen donanım modeli üzerinde bir veri paketi iletim protokolü tanımlanmıştır. Yüksek gerçek zaman performanslı, göreli olarak az işlemci gücü gerektiren bir mimari anahtar tasarım istekleridir. Önerilen mimarinin düşük işlem güçlü mikroişlemcilerde kullanılabilmesine imkân tanımak için K-Bus ilgilenilmeyen veri paketlerini belirleyerek işlemciye iletimi kesme ve bir paket iletimi boyunca hatta erişimi engelleme kabiliyetine sahiptir. Bu şekilde işlemciye yüklenen protokol ile ilgili yazılım yükü azaltılmıştır. Önerilen mimarinin ayırt edici özelliklerinden birisi, tek çevrim içerisinde farklı ağ modüllerinde bulunan verilere ulaşabilme kabiliyetidir. Bu özellik hem modüllere yazarken hem de modüllerden okurken kullanılabilir. K-Bus’ın diğer ayırt edici özelliği ise modül ve veri adresi kullanmadan, dağınık gerçek zamanlı ağ üzerinden, verilere ulaşabilme kabiliyetidir. Bu ayırt edici özelliklerinin yanı sıra, K-Bus, CAN ve Profibus gibi diğer modern gerçek zamanlı veri yollarında bulunan kabiliyetlere de sahiptir. Birçok konuşucu modül aynı veri yolu üzerinde bulunabilir. Bir veri paketi yayın olarak birden çok modüle iletilebilir. Veri paketleri için öncelik verilebilir. Paket çarpışmaları donanım düzeyinde önlenir. Hatalı veya çarpışan paketler yazılım tarafından tekrar yollanır. Anahtar Kelimeler: Gerçek zamanlı ağlar, dağınık kontrol sistemleri, insansız hava araçları