On some solutions of a functional equation related to the partial sums of the Riemann zeta function

In this paper, we prove that infinite-dimensional vector spaces of α-dense curves are generated by means of the functional equations f(x)+f(2x)+⋯+f(nx)=0, with n≥2, which are related to the partial sums of the Riemann zeta function. These curves α-densify a large class of compact sets of the plane for arbitrary small α, extending the known result that this holds for the cases n=2,3. Finally, we prove the existence of a family of solutions of such functional equation which has the property of quadrature in the compact that densifies, that is, the product of the length of the curve by the nth power of the density approaches the Jordan content of the compact set which the curve densifies.

Partial Product Reduction based on Look-Up Tables

In this paper a new technique for partial product reduction based on the use of look-up tables for efficient processing is presented. We describe how to construct counter devices with pre-calculated data and their subsequent integration into the whole operation. The development of reduction trees organizations for this kind of devices uses the inherent integration benefits of computer memories and offers an alternative implementation to classic operation methods. Therefore, in our experiments we compare our implementation model with CMOS technology model in homogeneous terms.

Embedding a restricted class of partial K-4-designs

Given a partial K-4-design (X, P), if x is an element of X is a vertex which occurs in exactly one block of P, then call x a free vertex. In this paper, a technique is described for obtaining a cubic embedding of any partial K-4-design with the property that every block in the partial design contains at least two free vertices.

All-optical TDM to WDM signal conversion and partial regeneration using XPM with triangular pulses

We propose a new all-optical, all-fibre scheme for conversion of time-division multiplexed to wavelength-division multiplexed signals using cross-phase modulation with triangular pulses. Partial signal regeneration using this technique is also demonstrated.

All-optical TDM to WDM signal conversion and partial regeneration using XPM with triangular pulses

We propose a new all-optical, all-fibre scheme for conversion of time-division multiplexed to wavelength-division multiplexed signals using cross-phase modulation with triangular pulses. Partial signal regeneration using this technique is also demonstrated.

Evaluation of the castability of a Co-Cr-Mo-W alloy varying the investing technique

O objetivo deste estudo foi comparar a fusibilidade de ligas de Co-Cr-Mo-W (Remanium 2000), Ni-Cr (Durabond) e Co-Cr-Mo (Vera-PDI), incluídas em revestimentos à base de fosfato, sílica ou utilizando uma técnica mista. Uma rede de nylon quadrada (10 X 10 mm) com 100 espaços abertos serviu de modelo para construção de padrões de cera, que foram incluídos com revestimento à base de sílica, revestimento fosfatado e técnica mista (camada de revestimento fosfatado com 2 mm de espessura + revestimento à base de sílica). Quarenta e cinco espécimes (5 para cada condição experimental) foram fundidos sob chama de gás-oxigênio e a seguir jateados com óxido de alumínio. O número de segmentos fundidos completos foi contado para obter uma percentagem designada como "valor de fusibilidade", representando a precisão da liga em reproduzir os detalhes do molde. A análise estatística por meio de ANOVA a dois critérios e teste Tukey mostrou que, comparando-se as ligas, a Remanium 2000 teve fusibilidade estaticamente semelhante (p>0,05) à da Vera PDI e inferior à da liga Durabond (p<0,05). Considerando os resultados da técnica mista, a liga Remanium 2000 teve menor valor de fusibilidade (p<0,05) que as ligas Durabond e Vera PDI, que apresentaram valores estatisticamente semelhantes entre si (p>0,05). Concluindo, a fusibilidade da liga de Co-Cr-Mo-W (Remanium 2000) foi comparável à da liga de Co-Cr (Vera PDI) e inferior à da liga de Ni-Cr alloy (Durabond). À exceção da liga Remanium 2000, a técnica de inclusão mista aumentou consideravelmente a capacidade das ligas testadas de reproduzir os detalhes do molde, quando comparada à técnica de inclusão em revestimento fosfatado. A técnica de inclusão mista representa uma alternativa para melhorar a fusibilidade de ligas de metais básicos sem afetar a qualidade superficial das peças metálicas.

Evaluation of the castability of a Co-Cr-Mo-W alloy varying the investing technique

O objetivo deste estudo foi comparar a fusibilidade de ligas de Co-Cr-Mo-W (Remanium 2000), Ni-Cr (Durabond) e Co-Cr-Mo (Vera-PDI), incluídas em revestimentos à base de fosfato, sílica ou utilizando uma técnica mista. Uma rede de nylon quadrada (10 X 10 mm) com 100 espaços abertos serviu de modelo para construção de padrões de cera, que foram incluídos com revestimento à base de sílica, revestimento fosfatado e técnica mista (camada de revestimento fosfatado com 2 mm de espessura + revestimento à base de sílica). Quarenta e cinco espécimes (5 para cada condição experimental) foram fundidos sob chama de gás-oxigênio e a seguir jateados com óxido de alumínio. O número de segmentos fundidos completos foi contado para obter uma percentagem designada como "valor de fusibilidade", representando a precisão da liga em reproduzir os detalhes do molde. A análise estatística por meio de ANOVA a dois critérios e teste Tukey mostrou que, comparando-se as ligas, a Remanium 2000 teve fusibilidade estaticamente semelhante (p>0,05) à da Vera PDI e inferior à da liga Durabond (p<0,05). Considerando os resultados da técnica mista, a liga Remanium 2000 teve menor valor de fusibilidade (p<0,05) que as ligas Durabond e Vera PDI, que apresentaram valores estatisticamente semelhantes entre si (p>0,05). Concluindo, a fusibilidade da liga de Co-Cr-Mo-W (Remanium 2000) foi comparável à da liga de Co-Cr (Vera PDI) e inferior à da liga de Ni-Cr alloy (Durabond). À exceção da liga Remanium 2000, a técnica de inclusão mista aumentou consideravelmente a capacidade das ligas testadas de reproduzir os detalhes do molde, quando comparada à técnica de inclusão em revestimento fosfatado. A técnica de inclusão mista representa uma alternativa para melhorar a fusibilidade de ligas de metais básicos sem afetar a qualidade superficial das peças metálicas.

Droplet etching of deep nanoholes for filling with self-aligned complex quantum structures

Strain-free epitaxial quantum dots (QDs) are fabricated by a combination of Al local droplet etching (LDE) of nanoholes in AlGaAs surfaces and subsequent hole filling with GaAs. The whole process is performed in a conventional molecular beam epitaxy (MBE) chamber. Autocorrelation measurements establish single-photon emission from LDE QDs with a very small correlation function g (2)(0)≃ 0.01 of the exciton emission. Here, we focus on the influence of the initial hole depth on the QD optical properties with the goal to create deep holes suited for filling with more complex nanostructures like quantum dot molecules (QDM). The depth of droplet etched nanoholes is controlled by the droplet material coverage and the process temperature, where a higher coverage or temperature yields deeper holes. The requirements of high quantum dot uniformity and narrow luminescence linewidth, which are often found in applications, set limits to the process temperature. At high temperatures, the hole depths become inhomogeneous and the linewidth rapidly increases beyond 640 °C. With the present process technique, we identify an upper limit of 40-nm hole depth if the linewidth has to remain below 100 μeV. Furthermore, we study the exciton fine-structure splitting which is increased from 4.6 μeV in 15-nm-deep to 7.9 μeV in 35-nm-deep holes. As an example for the functionalization of deep nanoholes, self-aligned vertically stacked GaAs QD pairs are fabricated by filling of holes with 35 nm depth. Exciton peaks from stacked dots show linewidths below 100 μeV which is close to that from single QDs.

Hallux rigidus: Arthroplasty or arthrodesis. What technique produces better results?

Hallux rígidus (HR) affects the first metatarsophalangeal joint (MTPJ) between 35% and 60% of the population over 65 years and there are multiple ways of treatment. Depending on the radiological stage where you find the deformity determines the procedure to be performed; in the early stages cheilectomy techniques and corrective osteotomy is performed while the more advanced ratings, the surgeon chooses destructive techniques considered as arthrodesis and arthroplasty. This final of degree project aims to focus on 1 MTPJ destructive techniques to clarify which of the procedures generates better results by a number of parameters; outcomes of the American Orthopaedic Foot scale and Ankle Society Hallux metatarsophalangeal Interphalangeal-scale (AOFAS), range of motion (ROM) of the 1ºAMTF, radiological classification. As for the implant arthroplasty technique, this article offers information on material and design that generates better relating to patient characteristics such as age, inflammatory joint diseases, viability and durability of the implant results. The conclusion from this review is that the values obtained in the arthrodesis according AOFAS decrease due to loss of mobility, but both techniques have similar values of effectiveness and concludes with the decision that the technique used is determined taking into account various factors and patient characteristics. Keywords: Hallux rígidus; (Hallux Rígidus) and surgery treatment; Hallux Rígidus arthrodesis; Hallux Rígidus arthroplasty; Hallux Rígidus (arthroplasty and arthrodesis).

Extraction, partial characterization and susceptibility to Hg2+ of acid phosphatase from the microalgae Pseudokirchneriella subcapitata.

Pseudokirchneriella subcapitata is a unicellular green algae widely distributed in freshwater and soils. Due to its cosmopolitan characteristic, its use is recommended by national and international protocols in ecotoxicity studies. The alteration of phosphatase activities by agriculture pollutants like heavy metals has been extensively used as a biomarker in risk assessment and biomonitoring. In this study, we compared the extraction of acid phosphatase from P. subcapitata by different procedures and we studied the stability, substrates specificity, kinetics and the effect of Hg2+ in the crude extract. The freezing and thawing technique associated with probe sonication was the most suitable method of extraction. The enzyme was stable when frozen at -20ºC for at least six months, showed an optimum pH of 5 and a Km value of 0.27 mM for p-nitrophenylphosphate (pNPP) as substrate. Some natural organic substrates were cleaved by a similar extent as the synthetic substrate pNPP. Short term exposure (24 hours) to Hg2+ had little effect but inhibition of the specific activity was observed after 7 days with EC50 (concentration of Hg2+ that promotes 50% decrease of specific activity) value of 12.63 μM Hg2+ .

Detailed analysis of a conservative difference approximation for the time fractional diffusion equation

Diffusion equations that use time fractional derivatives are attractive because they describe a wealth of problems involving non-Markovian Random walks. The time fractional diffusion equation (TFDE) is obtained from the standard diffusion equation by replacing the first-order time derivative with a fractional derivative of order α ∈ (0, 1). Developing numerical methods for solving fractional partial differential equations is a new research field and the theoretical analysis of the numerical methods associated with them is not fully developed. In this paper an explicit conservative difference approximation (ECDA) for TFDE is proposed. We give a detailed analysis for this ECDA and generate discrete models of random walk suitable for simulating random variables whose spatial probability density evolves in time according to this fractional diffusion equation. The stability and convergence of the ECDA for TFDE in a bounded domain are discussed. Finally, some numerical examples are presented to show the application of the present technique.