Quantum-classical correspondence in circularly polarized high harmonic generation

Using numerical simulations, we show that atomic high order harmonic generation, HHG, with a circularly polarized laser field offers an ideal framework for quantum-classical correspondence in strong field physics. With an appropriate initialization of the system, corresponding to a superposition of ground and excited state(s), simulated HHG spectra display a narrow strip of strong harmonic radiation preceded by a gap of missing harmonics in the lower part of the spectrum. In specific regions of the spectra, HHG tends to lock to circularly polarized harmonic emission. All these properties are shown to be closely related to a set of key classical periodic orbits that organize the recollision dynamics in an intense, circularly polarized field

ITU-PRP: Parallel and Distributed Computing Middleware for Java Developers

ITU-PRP provides a Parallel Programming Framework for Java Developers on which they can adapt their sequential application code to operate on a distributed multi-host parallel environment. Developers would implement parallel models, such as Loop Parallelism, Divide and Conquer, Master-Slave and Fork-Join by the help of an API Library provided under framework. Produced parallel applications would be submitted to a middleware called Parallel Running Platform (PRP), on which parallel resources for parallel processing are being organized and performed. The middleware creates Task Plans (TP) according to application’s parallel model, assigns best available resource Hosts, in order to perform fast parallel processing. Task Plans will be created dynamically in real time according to resources actual utilization status or availability, instead of predefined/preconfigured task plans. ITU-PRP achieves better efficiency on parallel processing over big data sets and distributes divided base data to multiple hosts to be operated by Coarse-Grained parallelism. According to this model distributed parallel tasks would operate independently with minimal interaction until processing ends

ITU-PRP: Parallel and Distributed Computing Middleware for Java Developers

ITU-PRP provides a Parallel Programming Framework for Java Developers on which they can adapt their sequential application code to operate on a distributed multi-host parallel environment. Developers would implement parallel models, such as Loop Parallelism, Divide and Conquer, Master-Slave and Fork-Join by the help of an API Library provided under framework. Produced parallel applications would be submitted to a middleware called Parallel Running Platform (PRP), on which parallel resources for parallel processing are being organized and performed. The middleware creates Task Plans (TP) according to application’s parallel model, assigns best available resource Hosts, in order to perform fast parallel processing. Task Plans will be created dynamically in real time according to resources actual utilization status or availability, instead of predefined/preconfigured task plans. ITU-PRP achieves better efficiency on parallel processing over big data sets and distributes divided base data to multiple hosts to be operated by Coarse-Grained parallelism. According to this model distributed parallel tasks would operate independently with minimal interaction until processing ends

Source-initiated geographical data flow approach for wireless ad hoc and sensor networks

Tasarsız (ad hoc) ve duyarga (sensör) ağlar, altyapısız ağlar olduğu için altyapılı ağlarda bol miktarda bulunan enerji, işlemci, bellek, bandgenişliği gibi kaynaklar kısıtlıdır ve özenle tüketilmelidir. Ağ elemanlarının boyutlarının çok küçük olması, enerjiyi en kısıtlı kaynak yapmaktadır. Ancak, kaynak ile varış arasında veri akışının sağlanması için kullanılan yöntemler enerji tüketimini arttırmaktadır. Bu nedenle, literatürde enerji-etkin yönlendirme protokolleri sunulmuştur. Bu protokollerden, coğrafi yer bilgisine dayanarak yönlendirme yapan protokoller, diğerlerine göre daha yüksek başarıma ve performans değerlerine sahiptir. Bu çalışmada, Durumsuz Ağırlıklı Yönlendirme (DAY) isimli bir özgün kaynak-başlatmalı veri akış tekniği sunulmaktadır. Düğümler sadece kendi sanal coğrafi yer bilgilerini bilmekte, ağ topololoji bilgisine ihtiyaç duymamaktadır. Her düğüm kendi ağırlığını hesaplamaktadır. Başlangıçta bu değer varışa olan mesafedir. Düğümler kendilerine gelen paketlerin içindeki ağırlık bilgilerine bakarak paketi tekrar göndermeye veya düşürmeye karar vermektedir. Bu karşılaştırma işlemi durumsuz olma özelliğini sağlamaktadır. Ağırlık parametresi sadece yer bilgisini içerebildiği gibi düğümün kalan enerjisi gibi Servis Kalitesi parametre bilgisini de içerebilir. Servis Kalite bilgisi sistemin yaşamömrünü arttırmaya yöneliktir. Durumsuz olma özelliği ile de, yönlendirme tablosu tutulan algoritmalarda görülen iletişim yükü büyük oranda azalmaktadır. DAY, aynı zamanda, güvenirliği sağlayan ve gerçek-zamanlı veri için de gerekli olan çoklu-yollar veya örülü çoklu-yollar kullanır. Tekrar-gönderimlerde eşik değerlerinin kullanımı, sistemde esnek ve enerji etkin bir veri akışı sağlar. Aynı zamanda, DAY, MAC-katmanından bağımsız çalışan ilk durumsuz coğrafi yönlendirme tekniğidir.                                                    Anahtar Kelimeler: Kablosuz ağlar, gezgin ağlar, sensör ağlar, iletişim, yol atama, yönlendirme. Routing without tables can be achieved by using location information of the nodes retrieved from GPS (Global Positioning System) or by applying a localization algorithm. In geographic routing protocols, nodes know their actual or relative positions with respect to a reference point, and share this information with immediate neighbour nodes for routing process. Geographic routing protocols use only local topology information and do not have any update overhead. Therefore, they provide scalability in mobile networks with respect to conventional routing protocols. Geographic routing protocols use greedy scheme or beaconless scheme for routing. In greedy schemes, nodes select the best next node on the route by using the local topology information. Collecting local topology information in greedy schemes consumes more energy than beaconless schemes due to reduced transmissions in the latter one. On the other hand, beaconless routing protocols in the literature propose solutions to be implemented at the MAC (Medium Access Control) layer. In those solutions, RTS (Request To Send) and CTS (Clear To Send) packets are also used for implementing routing protocol that increases the complexity of the MAC layer. However, sorting routing problem at the MAC layer is against the well-defined communication architecture. Besides that, those solutions become dependent to the MAC layer they use. In this study, a novel stateless data flow approach and routing algorithm for wireless sensor networks is proposed which is completely MAC-layer independent. Nodes do not have to be aware of local or global topology information. Routing is achieved without keeping tables. Nodes geographical positions are sufficient for routing process. A new metric called weight that is derived from nodes own position is used in routing process. The position can be either geographical or relative to a reference point system wide. Instead of the position, the weight value of the transmitting node is inserted into the packet. Each node on the route involves in routing process by considering its weight and the information in the received packet. To limit the number of forwarding nodes, a threshold is set in terms of the weight metric. On a packet receive; a node broadcasts the packet if its weight is between the weights of the transmitting node and the destination node and if also its weight difference greater than the threshold value. Besides that, decision to transmit includes QoS parameters such as power-left at the node to keep energy-limited nodes out of the route. The threshold value can be adjusted to save energy by limiting the number of retransmitting nodes. The threshold value can also be adjusted for reliability. More relaying in number causes the data to flow over multiple paths. Data transportation over multiple paths provides reliability. Reliability requirements challenge with the energy saving requirements. Therefore, threshold value can be used to balance these requirements as needs. Thirdly, the threshold value can be adjusted for void recovery. In case of void detection, the transmitting node decreases the threshold value allowing more nodes to be in data flow algorithm. By this way, nodes that may circumvent the void are forced to relay the data packets. Fourthly, the threshold value should be adjusted according to the node density in the network. In dense networks, the threshold value can be set to be high by default to limit the retransmitting nodes. In non-dense networks, the threshold value can be set to be low. The proposed algorithm, SWR, has the followingproperties:  SWR provides scalability by not using routing tables, and by not beaconing. SWR simplifies routing process by using a weight metric and designing an appropriate algorithm for routing. SWR decreases calculations, delay, and resource requirements (such as processor and memory) at nodes by using weight metric. SWR decreases energy consumption by not beaconing, by using position-based routing based on threshold and considering the energy levels of the nodes.  SWR provides reliability by using multipaths. SWR executes routing process completely in network layer, independent from the MAC layer used below.  Keywords: Wireless networks, mobile networks, sensor networks, communications, routing, network layer.

TKA following high tibial osteotomy versus primary TKA - a matched pair analysis

<p>Abstract</p> <p>Background</p> <p>High tibial osteotomy (HTO) is a well established technique for the treatment of medial osteoarthritis of the knee with varus malalignment. Results of total knee arthroplasty (TKA) after previous HTO are still discussed controversially. The aim of this study was to elucidate the clinical and radiological results as well as perioperative data of prior HTO on TKA.</p> <p>Methods</p> <p>Forty-one TKA after HTO were compared to 41 primary TKA at minimum of six years follow-up. Patients were matched according to age, gender, follow-up, etiology, and prosthetic design. Surgical data and complications were evaluated. Clinical outcome was assessed using a number of clinical scores and the visual analogue scale (VAS) for pain. X-rays were evaluated by the method of the American Knee Society. The patellar position was measured by the Insall-Salvati ratio.</p> <p>Results</p> <p>There was no significant difference in mean operation time (p = 0.47) and complication rate (p = 0.08). The Knee Score of the KSS (p = 0.0007) and the ROM (p = 0.006 for extension and p = 0.004 for flexion, respectively) were significantly better in the control group. Mid-term results of the VAS, WOMAC, Lequesne, UCLA, Feller's Patellar Score and SF-36 showed no significant difference. Femoral and tibial component alignment were similar in both groups. One tibial component showed suspect radiolucencies in the HTO group. The Insall-Salvati ratio showed three patients with patella alta and one patient with patella baja in the HTO group. At latest follow-up all implants were still in place.</p> <p>Conclusions</p> <p>Evaluating the clinical and radiological outcome, significant differences were only detected for range of motion and the Knee Score of the KSS. The present study suggests that the results of TKA with and without prior HTO are mainly identical. Although patients with a previous HTO had more complications, no statistically significant differences were noted with this group size.</p

Biochemical characterization of a molecular switch involving the heat shock protein ClpC, which controls the activity of ComK, the competence transcription factor of Bacillus subtilis

Development of genetic competence in Bacillus subtilis is controlled by the competence-specific transcription factor ComK. ComK activates transcription of itself and several other genes required for competence. The activity of ComK is controlled by other genes including mecA, clpC, and comS. We have used purified ComK, MecA, ClpC, and synthetic ComS to study their interactions and have demonstrated the following mechanism for ComK regulation. ClpC, in the presence of ATP, forms a ternary complex with MecA and ComK, which prevents ComK from binding to its specific DNA target. This complex dissociates when ComS is added, liberating active ComK. ClpC and MecA function as a molecular switch, in which MecA confers molecular recognition, connecting ClpC to ComK and to ComS

Análise de timol em cera de abelha por micro-extracção em fase sólida (SPME)

A aplicação contínua de acaricídas lipofílicos sintéticos no tratamento das abelhas conduz a uma acumulação que depende da frequência, lipofilicidade e quantidade de princípio activo utilizada. Este efeito é mais acentuado na cera de abelha que no mel, no entanto, e porque a persistência destes resíduos é elevada, provoca o aparecimento de resistências e a perda do seu efeito acaricida.[1] Esta razão levou à pesquisa de outros compostos alternativos não tóxicos e não persistentes, com efeito sobre o ácaro das abelhas, Varroa Jacobsoni. Entre estes compostos encontra-se o timol, um composto fenólico, volátil, presente no tomilho. Dos diversos componentes dos óleos essenciais este é sem dúvida o que demonstrou maior efeito acaricida, utilizando-se no tratamento das abelhas directamente ou como componente de diversas formulações.[2] Em Portugal, foi introduzido muito recentemente sob a forma comercial de APIGUARD: um gel, à base de timol, que controla termicamente a libertação do princípio activo. O controlo dos resíduos de timol na cera de abelha e no mel é assim um desafio actual quer do ponto de vista sanitário quer de qualidade alimentar. A micro-extracção em fase sólida (SPME) é uma técnica de preparação de amostras que se baseia na sorção de analítos no revestimento de uma fibra de sílica fundida e posterior desorção térmica no injector de um cromatógrafo em fase gasosa (GC). Para além de combinar num único processo etapas de extracção, purificação e concentração dos analitos, a técnica de SPME apresenta uma série de vantagens relativamente às técnicas de extracção convencionais, como a extracção líquido-líquido e extracção em fase sólida, nomeadamente a sua relativa simplicidade e rapidez, reduzido custo e não utilização de solventes para a extracção de analitos, para além de permitir a extracção por imersão directa na amostra gasosa ou líquida e extracção por amostragem do espaço-de-cabeça da amostra líquida ou sólida.[3] Ao contrário das técnicas tradicionais, que permitem uma extracção quantitativa dos analitos, a técnica de SPME baseia-se num equilíbrio de partição do analito. Esta particularidade torna a técnica de SPME bastante sensível a parâmetros experimentais que possam afectar os coeficientes de partição dos analitos e, consequentemente, a sensibilidade e reprodutibilidade dos resultados.[4] O objectivo deste trabalho é o desenvolvimento de uma metodologia para a análise de timol em ceras contaminadas, utilizando como padrão interno a benzofenona. Em primeiro lugar, procedeu-se à optimização da técnica através da determinação da quantidade de cera, temperatura de análise e período de contacto da fibra com o espaço-de-cabeça da amostra mais adequados para o caso em estudo. Numa segunda fase, procedeu-se à análise de diversas lâminas de cera contaminadas propositadamente com timol e sujeitas a diferentes condições de armazenamento: em frio, ao ar e em estufa. Finalmente, procedeu-se à construção da curva de calibração e quantificação do timol presente nas diversas amostras de cera analisadas. Considerando-se os resultados, para os níveis de contaminação avaliados, as condições analíticas mais adequadas ocorrem com a utilização de 1 g de cera, mantendo-se a fibra em contacto com o espaço-de-cabeça durante 40 minutos a uma temperatura de 60 ºC. Nestas condições experimentais foi possível obter uma boa correlação linear (r2=0,990) no intervalo de concentrações [3,5-14 mg/g]. A quantidade de timol encontrada nas amostras é significativamente inferior à colocada durante o processo de fabrico das lâminas, pelo que o processo de conservação não é o mais adequado, sendo evidente uma menor quantidade de timol quando a lâmina de cera é colocada na estufa