A Closed Form Selected Mapping Algorithm for PAPR Reduction in OFDM Multicarrier Transmission

Nowadays, the demand for communication multi-carriers' channels, where the sub-channels are made mutually independent by using orthogonal frequency division multiplexing (OFDM), is widespread both for wireless and wired communication systems. Even if OFDM is a spectrally efficient modulation scheme, due to the allowed number of subcarriers, high data rate, and good coverage, the transmitted signal can present high peak values in the time domain, due to inverse fast Fourier transform operations. This gives rise to high peak-to-average power ratio (PAPR) with respect to single carrier systems. These peaks can saturate the transmitting amplifiers, modifying the shape of the OFDM symbol and affecting its information content, and they give rise to electromagnetic compatibility issues for the surrounding electric devices. In this paper, a closed form PAPR reduction algorithm is proposed, which belongs to selected mapping (SLM) methods. These methods consist in shifting the phases of the components to minimize the amplitude of the peaks. The determination of the optimal set of phase shifts is a very complex problem; therefore, the SLM approaches proposed in literature all resort to iterative algorithms. Moreover, as this calculation must be performed online, both the computational cost and the effect on the bit rate (BR) cannot be established a priori. The proposed analytic algorithm finds the optimal phase shifts of an approximated formulation of the PAPR. Simulation results outperform unprocessed conventional OFDM transmission by several dBs. Moreover, the complementary cumulative distribution function (CCDF) shows that, in most of the packets, the proposed algorithm reduces the PAPR if compared with randomly selected phase shifts. For example, with a number of shifted phases U=8, the CCFD curves corresponding to the analytical and random methods intersect at a probability value equal to 10(-2), which means that in 99% of cases the former method reduces the PAPR more than the latter one. This is also confirmed by the value of the gain, which, at the same number of shifted phases and at the probability value equal to 10(-1), changes from 2.09 dB for the analytical to 1.68 dB for the random SLM

Multi-Objective Optimization Methods Based on Artificial Neural Networks

Search algorithms aim to find solutions or objects with specified properties and constraints in a large solution search space or among a collection of objects. A solution can be a set of value assignments to variables that will satisfy the constraints or a sub-structure of a given discrete structure. In addition, there are search algorithms, mostly probabilistic, that are designed for the prospective quantum computer. This book demonstrates the wide applicability of search algorithms for the purpose of developing useful and practical solutions to problems that arise in a variety of problem domains. Although it is targeted to a wide group of readers: researchers, graduate students, and practitioners, it does not offer an exhaustive coverage of search algorithms and applications. The chapters are organized into three parts: Population-based and quantum search algorithms, Search algorithms for image and video processing, and Search algorithms for engineering applications

Metal free graphene oxide (GO) nanosheets and pristine-single wall carbon nanotubes (p-SWCNTs) biocompatibility investigation: a comparative study in different human cell lines

The in vitro biocompatibility of Graphene Oxide (GO) nanosheets, which were obtained by the electrochemical exfoliation of graphite electrodes in an electrolytic bath containing salts, was compared with the pristine Single Wall Carbon Nanotubes (p-SWCNTs) under the same experimental conditions in different human cell lines. The cells were treated with different concentrations of GO and SWCNTs for up to 48 h. GO did not induce any significant morphological or functional modifications (demonstrating a high biocompatibility), while SWNCTs were toxic at any concentration used after a few hours of treatment. The cell viability or cytotoxicity were detected by the trypan blue assay and the lactate dehydrogenase LDH quantitative enzymatic test. The Confocal Laser Scanning Microscopy (CLSM) and transmission electron microscopy (TEM) analysis demonstrated the uptake and internalization of GO sheets into cells, which was localized mainly in the cytoplasm. Different results were observed in the same cell lines treated with p-SWCNTs. TEM and CLSM (Confocal Laser Scanning Microscopy) showed that the p-SWCNTs induced vacuolization in the cytoplasm, disruption of cellular architecture and damage to the nuclei. The most important result of this study is our finding of a higher GO biocompatibility compared to the p-SWCNTs in the same cell lines. This means that GO nanosheets, which are obtained by the electrochemical exfoliation of a graphite-based electrode (carried out in saline solutions or other physiological working media) could represent an eligible nanocarrier for drug delivery, gene transfection and molecular cell imaging tests

Einfluss des Wachstumsfaktors Insulin-like growth factor-I (IGF-I) auf das Follikelwachstum beim Weißbüschelaffen (Callithrix jacchus)

Einfluss des Wachstumsfaktors Insulin-like growth factor-I (IGF-I) auf das Follikelwachstum beim Weißbüschelaffen (Callithrix jacchus) Aus dem Veterinär-Physiologisch-Chemischen Institut der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im September 2010 (86 S., 16 Abb., 9 Tab., 225 Lit., 4 S. Anhang) Schlüsselwörter: Insulin-like Growth Factor-I (IGF-I), Granulosazellen, Steroidhormone (Östradiol, Progesteron), Gonadotropine (FSH, hCG) In der vorliegenden Studie wurde die Rolle von IGF-I und das Zusammenwirken mit den Gonadotropinen (FSH, hCG) auf die Sekretion der Steroidhormone (Progesteron, Östradiol) kultivierter Granulosazellen von 13 Weißbüschelaffen untersucht, um zu prüfen, ob und wie weit IGF-I die Sekretion und Reifung der Granulosazellen beeinflusst. Für die in vitro-Experimente wurden Zellkulturen mit Granulosazellen kleiner ( 0,5 - 1 mm) und präovulatorischer Follikel ( > 2 mm) von Ovarien am 7. Tag der Follikelphase verwendet. Vor jedem Versuch wurde das Wachstum der Follikel durch zwei Ultraschalluntersuchungen kontrolliert. Während der Kultur wurden drei Inkubationsintervalle von je 48 h durchgeführt. Die Zellen wurden mit IGF-I allein oder in Kombination mit FSH bzw. hCG stimuliert. Zum Teil wurden die Gonadotropine auch zur Prästimulation verwendet. Das Signifikanzniveau der Hormoneffekte lag bei p<0,05. Bei den Granulosazellen kleiner Follikel lässt sich durch die alleinige Gabe von IGF-I nur am Ende der Kultur (144 h) eine signifikante Erhöhung der Progesteronsekretion feststellen. Bei einer Kombinationsgabe von IGF-I und FSH findet sich schon am Anfang (48 h) ein signifikanter Einfluss auf die Sekretion von Progesteron und Östradiol. Bei der Progesteronsekretion ist der Effekt der Kombination signifikant höher als bei Einzelgabe beider Hormone. Dagegen ist bei der Östradiolsekretion der Effekt der Kombination zwar nicht höher als bei einer alleinigen Gabe von FSH, aber die Zellen reagieren wesentlich schneller auf IGF-I, wenn sie zusammen mit FSH stimuliert werden. Keine signifikante Wirkung in der Steroidhormonsekretion ruft die Hormonkombination IGF-I und hCG im Vergleich zur alleinigen Gabe der beiden Hormone hervor. Bei dem Vergleich beider Gonadotropine ist eine signifikante Erhöhung der Steroidhormonsekretion nur bei alleiniger Gabe von FSH zu beobachten. Bei den Experimenten mit Prästimulationen (FSH oder hCG) lässt sich nur bei der FSH-Prästimulation mit einer nachfolgenden Kombinationsgabe von hCG und IGF-I eine signifikante Erhöhung der Steroidhormonsekretion feststellen. Dies bedeutet, dass FSH die kleinen Granulosazellen auf die Wirkung von hCG sensibilisiert, wobei IGF-I diesen Vorgang unterstützt. Im Gegensatz zu den kleinen Follikeln lässt sich bei den Granulosazellen der präovulatorischen Follikel ein signifikanter Effekt von verschiedenen Hormonstimulationen schon früh beobachten. Durch alleinige IGF-I-Gabe lässt sich bereits am Anfang der Kultur (48 h) eine signifikante Erhöhung der Steroidhormonsekretion feststellen. Eine Kombinationsgabe von IGF-I und der Gonadotropine (FSH oder hCG) zeigt, dass die Kombination mit FSH zu einer signifikanten Erhöhung beider Steroide im Vergleich zur Kontrolle führt. Dagegen zeigt sich bei einer Kombination von IGF-I und hCG eine signifikante Erhöhung der Steroidhormonsekretion schon ab 48 h sowohl im Vergleich zur Kontrolle als auch zur alleinigen Gabe dieser Hormone. Bei der Untersuchung des Effekts beider Gonadotropine (FSH oder hCG) ist schon ab 48 h ein signifikanter Effekt auf beide Steroidhormone zu erkennen. Beide Gonadotropinprästimulationen (FSH oder hCG) mit nachfolgender Hormonkombination (hCG und IGF-I) führen bei den Granulosazellen der präovulatorischen Follikel zu einer signifikant geringeren Steroidhormonsekretion im Vergleich zur Gabe von hCG und IGF-I ohne Prästimulation. Die Zellen reagieren offenbar in dieser Art und Weise, um eine mögliche übermäßige Steroidgenese, und somit eine pathologische Situation, zu verhindern. Die vorliegende Arbeit zeigt, dass IGF-I bei den kleinen und präovulatorischen Follikeln unterschiedliche Wirkungen hervorruft. Es scheint, dass IGF-I die Sekretion von Progesteron und Östradiol auf unterschiedliche Art und Weise beeinflusst, und dass die Granulosazellen der Weißbüschelaffen erst während der Follikelentwicklung die Fähigkeit erwerben, auf IGFI entsprechend zu reagieren. Die Ergebnisse zeigen weiterhin, dass IGF-I bei den Granulosazellen der kleinen Follikel eine eher unterstützende Rolle für die Gonadotropine spielt, und dass IGF-I mit den Gonadotropinen bei der Reifung und der Differenzierung der Follikel mitwirkt. Möglicherweise spielt IGF-I auch während der Entwicklung und des Wachstums des präovulatorischen Follikels sowie bei der Regulierung der Progesteronsekretion eine Rolle. Die vorliegenden Ergebnisse unterstützen die Hypothese, dass IGF-I zusammen mit hCG die Zelldifferenzierung bei den Granulosazellen der präovulatorischen Follikel fördert. Außerdem kann vermutet werden, dass bei den Granulosazellen der präovulatorischen Follikel IGF-I zusammen mit FSH in unabhängiger Weise wirkt. Abschließend kann gesagt werden, dass ein Zusammenwirken zwischen den Gonadotropinen und IGF-I in Bezug auf die Bildung des präovulatorischen Follikels und die darauffolgende Ovulation existiert, dies gilt es auch bei pathologischen Situationen der Follikelreifung und Ovulation zu berücksichtigen

Knoop microhardness and FT-Raman evaluation of composite resins: influence of opacity and photoactivation source

The aim of this study was to evaluate the degree of conversion by Knoop microhardness (KHN) and FT-Raman spectroscopy (FTIR) of one nanofilled (Filtek Supreme-3M-ESPE [FS]) and one microhybrid composite (Charisma-Heraeus-Kulzer [CH]), each with different opacities, namely enamel, dentin, and translucent, which were photo-activated by a quartz-tungsten-halogen lamp (QTH) and a light-emitting diode (LED). Resin was bulk inserted into a disc-shaped mold that was 2.0 mm thick and 4 mm in diameter, obtaining 10 samples per group. KHN and FTIR values were analyzed by two-way ANOVA and Tukey's tests (&#945; = 0.05). Nanofilled resin activated by a LED presented higher microhardness values than samples activated by a QTH for dentin opacity (p < 0.05). The microhybrid resin showed no differences in KHN or FTIR values with different activation sources or opacity. The nanofilled dentin and enamel resins showed lower FTIR values than the translucent resin. The KHN values of the translucent resins were not influenced by the light source

Importance of perforating vessels in nipple-sparing mastectomy. an anatomical description

BACKGROUND: Nipple-sparing mastectomy (NSM), understood as an oncologically valid procedure, is relatively new, and is an evolution of traditional mastectomy, particularly in relation to breast-conserving surgery. The anterior perforating branches are responsible for the cutaneous vascularization of the breast skin, and their preservation is a fundamental step to avoid possible postoperative necrosis. Therefore, evaluating the potential complications of cancer-related reconstructive surgical procedures such as NSM, both the distance of the tumoral lesion from the skin and the surgical incision site should be carefully considered. The preferred site of incision corresponds to the inframammary fold or possibly the periareolar area. METHODS: We retrospectively reviewed 113 patients who underwent NSM from January 2005 to October 2012 to evaluate skin complications. The anatomical study was performed by magnetic resonance imaging of the breast. RESULTS: Only one of the 113 women who had undergone a NSM procedure had total necrosis (0.9%) and six patients had partial necrosis (5.8%) of the nipple-areola complex

AMBIENTAL IMPACTS CAUSED BY THE APPLICATION OF POULTRY SLAUGHTERHOUSE WASTEWATER ON SOILS

Os frigoríficos de aves geram quantidade significativa de efluentes líquidos, pois, para o abate de cada ave são gastos aproximadamente 15 litros de água. As principais características desses efluentes são as elevada carga orgânica e concentração de nutrientes, principalmente nitrogênio e fósforo. Uma alternativa para reduzir custos de tratamento com esse resíduo seria utilizá-lo de maneira direta no solo. Os nutrientes presentes no efluente podem ser utilizados na agricultura para que substituam os fertilizantes comerciais sintéticos. O presente experimento, com o objetivo de avaliar a aplicação de efluente bruto de frigorífico de frango em um Latossolo Vermelho, observou os possíveis impactos ambientais pela lixiviação de íons, a partir da montagem de colunas em PVC de 10 x 60 cm (diâmetro x altura), preenchidas com 50 cm de solo. Nas colunas de solo, foram aplicadas quatro doses, com quatro repetições, as quais foram definidas segundo a necessidade de nitrogênio para produtividade de 9,17 Mg ha-1 de milho (0, 50, 100, 150 e 200%). Em cada coluna, foram feitas cinco aplicações de água de 1,42 L, que corresponderam à maior precipitação registrada na região (180,95 mm no dia). Os teores dos íons Ca, Mg, K e P lixiviados não ultrapassam os limites de qualidade de água, estabelecidos pela resolução do CONAMA; enquanto os teores de N extrapolaram muito tais condições. A análise de percolação apontou diferenças no incremento de N, K e Carbono Orgânico nas camadas superiores (0-20 cm) em relação às camadas inferiores (20-50 cm)

Nitrogen budget and statistical entropy analysis of the Tiber River catchment, a highly anthropized environment

Modern farming causes a decline in the recycling of the soil's inorganic matter due to losses by leaching, runoff, or infiltration into the groundwater. The Soil System Budget approach was applied to evaluate the net N budget at the catchment and sub-catchment levels of the Tiber River (central Italy) in order to establish the causes for different N budgets among the sub-catchments. Statistical Entropy Analysis (SEA) was used to evaluate the N efficiency of the Tiber River and its sub-catchments, providing information on the dispersion of different N forms in the environment. The total N inputs exceeded the total outputs, showing a low N retention (15.8%) at the catchment level, although some sub-catchments showed higher N retention values. The Utilized Agricultural Area was important in the determination of the N balance, as it was linked to zoo- and agricultural activities, although the Random Forest analysis showed that the importance ranking changed with the land use. The low N retention of the Tiber catchment was due to the soil characteristics (Cambisols and Leptosols), loads from atmospheric deposition, biological fixation, and the livestock industry. The SEA simulations showed a reduction of the N released into the atmosphere and groundwater compartments from 34% to 6% through a reduction of the N loads by 50%

Are torque values of preadjusted brackets precise?

OBJECTIVE: The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. MATERIAL AND METHODS: Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. RESULTS: The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º) presented statistically significant difference from the proposed values (-7º). For the mandibular canines, American Orthodontics (-6.34º) and Ortho Organizers (-6.25º) presented statistically significant differences from the standards (-6º). Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. CONCLUSIONS: There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment