Proposta de um esquema MIMO-OFDM com máxima diversidade em frequência para canais variantes no tempo

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica.O projeto de sistemas de comunicação sem fio, com o propósito de minimizar a probabilidade de erro de bits, é um problema atual e vem sendo motivado cada vez mais pela crescente demanda por altas taxas de transmissão. Não há dúvida de que o sistema OFDM e o uso de múltiplas antenas, utilizando técnicas de diversidade, são parcelas significativas na busca de soluções para atender tal demanda. Diante de tal cenário, tirar proveito da diversidade a fim de garantir ganhos que minimizem a degradação provocada pelo desvanecimento torna-se algo crucial. Isto revela a importância de cada símbolo de informação ser cuidadosamente organizado em cada subportadora e em cada antena transmissora para que réplicas do sinal sejam submetidas a desvanecimentos descorrelacionados. Neste sentido, um novo esquema será apresentado de modo a explorar diversidade no espaço e na freqüência, além de garantir ganho em canais variantes no tempo. Este trabalho combina repetições do código espácio-temporal que possam garantir a máxima diversidade em freqüência, juntamente com o espalhamento temporal da informação por meio da transformada de Hadamard, além do uso da modulação OFDM para atuar em canais com desvanecimento seletivo em freqüência. Apesar da nova proposta apresentar uma redução na taxa de transmissão, os resultados de simulação mostram que o desempenho do novo esquema é bom o suficiente para atuar em situações desfavoráveis de canal com desvanecimento Rayleigh. The project of wireless communication systems with the purpose of minimizing the bit error rate is a current problem and it is motivated increasingly by the growing demand for high data rates. There is no doubt that the use of multiple antennas, integrated with diversity techniques and OFDM modulation, are meaningful parts of the solution for such demand. Considering this background, it is critical to take advantage of diversity in order to ensure gains that minimize distortions caused by fading. Then, it reveals that the information symbols must be carefully spread over the tones as well as over the transmit antennas so that copies of the signal are transmitted in uncorrelated fading. In this sense, a new proposal is presented by the means of exploring diversity in space and in frequency, as well as ensuring gain in time-varying channels. The new scheme combines duplications of the space-time codes so that it can guarantee full diversity in frequency, along with time spreading of the data symbols through the Hadamard transform and also OFDM modulation for frequency selective fading channels. Although the new proposal exhibit a reduction in data rate, simulation results show that the performance of the new scheme is good enough to be used in any particular channel condition in a Rayleigh fading channel

Application of OSL strips in CT dosimetry according to the AAPM methodology

Computed tomography (CT) images contribute to high-quality medical diagnosis, but radiation dose can be quite high, requiring accurate assessment. CT dose index (CTDI) was developed for dosimetric purposes, but for scanners operated exclusively in axial mode. Nowadays, CTDI underestimate patient dose in helical CT exams. AAPM report TG111 (2010) suggested a new metric in which the patient's radiation dose is obtained from dose profiles constructed from several measurements made with a small ionization chamber. It is also possible to obtain dose profiles using properly calibrated OSL (optically stimulated luminescence) strips. The main objective of the present work is to contribute to optimizing CT dosimetry, comparing dose profiles obtained with OSL strips with measurements obtained by other authors. In this work, a “pencil” ionization chamber and 20 cm x 0.3 cm OSL strips were X-ray-irradiated, in air and in the holes of two cylindrical CT phantoms, using 100, 120, 140 kV peak voltages, both in lab and in a clinical CT scanner. Irradiated strips were read using an OSL reader built in the GDRFM. OSL profiles were calibrated against ionization chamber. From them, CTDIw and CTDIvol values were determined, differing approximately 3.9% from those of the CT scanner. From the profiles, also the planar equilibrium dose Deq,p (TG111) was evaluated in some CT protocols; Deq,p exceeded the CTDI values from the CT scanner in every case. E.g.: The percentage difference between Deq,p and CTDIvol for the head phantom ranged between 33-25%. Thus, in some cases, it could be advantageous to use calibrated OSL dosimeters instead of ionization chambers to obtain the profiles, saving time, because it is possible to obtain five OSL profiles from a single phantom irradiation

Tracer-aided ecohydrological modelling across climate, land cover, and topographical gradients in the tropics

Funding Information: We thank the Leverhulme Trust funded ISOLAND (RPG‐2018‐375) project, the IAEA‐CRP F31005 contract 22904, the IAEA‐CRP F31006, and the IAEA‐CRP F31006 and UCR C1038 funded the IsoRSM project. We also acknowledge the many suggestions by two anonymous reviewers that improved this paper. Funding Information: We thank the Leverhulme Trust funded ISOLAND (RPG-2018-375) project, the IAEA-CRP F31005 contract 22904, the IAEA-CRP F31006, and the IAEA-CRP F31006 and UCR C1038 funded the IsoRSM project. We also acknowledge the many suggestions by two anonymous reviewers that improved this paper. Publisher Copyright: © 2023 The Authors. Hydrological Processes published by John Wiley & Sons Ltd.Peer reviewedPublisher PD

Exploring the Relationship Between Mental Well-Being, Exercise Routines, and the Intake of Image and Performance Enhancing Drugs During the Coronavirus Disease 2019 Pandemic : A Comparison Across Sport Disciplines

Funding Information: This research was supported by the European Network for the Problematic Use of the Internet, the COST European Cooperation in Science and Technology, a Grant-in-Aid for Scientific Research on Innovative Areas (Ministry of Education, Culture Sports, Science and Technology, Japan, 16H06400, 16H06402, 16H06395, and 16H06397), a Grant-in-Aid for Scientific Research (A) (Japan Society for The Promotion of Science, 19H00518), a Grant-in-Aid by the Smoking Research Foundation, and Grant-in-Aid for Young Scientists (20K13821), the Hungarian National Research, Development and Innovation Office (KKP126835; ELTE Thematic Excellence Programme 2020, KP2020-IKA-05). Publisher Copyright: © Copyright © 2021 Shibata, Burkauskas, Dores, Kobayashi, Yoshimura, Simonato, De Luca, Cicconcelli, Giorgetti, Carvalho, Barbosa, Monteiro, Murai, Gómez-Martínez, Demetrovics, Ábel, Szabo, Ventola, Arroyo-Anlló, Santos-Labrador, Griskova-Bulanova, Pranckeviciene, Bersani, Fujiwara and Corazza.Introduction: Physical distancing under the coronavirus disease 2019 (COVID-19) pandemic had a significant impact on lifestyles, including exercise routines. In this study, we examined the relationship between mental health and addictive behaviors, such as excessive exercise and the use of image and performance enhancing drugs (IPEDs) across 12 sport disciplines. Materials and methods: A large cross-sectional sample of the adult population (N = 2,295) was surveyed. The mean age was 33.09 (SD = 11.40). The number of male participants was 668 (30.0%). The use of IPEDs was assessed in conjunction with psychometric measures such as the Exercise Addiction Inventory (EAI) and the Appearance Anxiety Inventory (AAI). The participants were grouped into activity group (AG) and non-activity group (NAG) according to the presence or absence of their exercise habits. The results were compared between these groups, as well as across sport disciplines, while taking into account the relationship between different psychological measures and IPEDs consumption. Results: The frequency of IPEDs use was higher among AG (34.6%) than NAG (14.6%), although AG participants reported less history of addictions (7.1%) than NAG (11.8%). The logistic regression analysis revealed that scores equal to or above cutoff points, in both the EAI and AAI, predicted the IPEDs use. Regarding the differences across the various sport disciplines, those who were involved in practicing Weight Lifting and Cross Fit were found to be more at risk of excessive exercising and more inclined to use a wide range of IPEDs. Conclusions: Although exercise could help to increase well-being and prevent addictions during the COVID-19 pandemic, our results show that those in the AG are particularly vulnerable to excessive IPEDs use. Sport disciplines associated with higher EAI and AAI scores have also shown a higher tendency to excessive IPEDs use. Furthermore, the factor of having above the cutoff scores in EAI or AAI in each sport could indicate larger IPEDs consumption regardless of the discipline. In light of the current findings, it is necessary to better define the “non-excessive” levels of exercise in various sport disciplines and an adequate intake of IPEDs to ensure the safety and well-being of people during a pandemic.Peer reviewe

Plk1 negatively regulates Cep55 recruitment to the midbody to ensure orderly abscission

Degradation of Plk1 during mitotic exit allows recruitment of the Cep55 abscission factor and timely cytokinesis

Antibody-mediated inhibition of the FGFR1c isoform induces a catabolic lean state in Siberian hamsters

Hypothalamic tanycytes are considered to function as sensors of peripheral metabolism [1]. To facilitate this role, they express a wide range of receptors, including fibroblast growth factor receptor 1 (FGFR1). Using a monoclonal antibody (IMC-H7) that selectively antagonizes the FGFR1c isoform [2], we investigated possible actions of FGFR1c in a natural animal model of adiposity, the Siberian hamster. Infusion of IMC-H7 into the third ventricle suppressed appetite and increased energy expenditure. Likewise, peripheral treatment with IMC-H7 decreased appetite and body weight and increased energy expenditure and fat oxidation. A greater reduction in body weight and caloric intake was observed in response to IMC-H7 during the long-day fat state as compared to the short-day lean state. This enhanced response to IMC-H7 was also observed in calorically restricted hamsters maintained in long days, suggesting that it is the central photoperiodic state rather than the peripheral adiposity that determines the response to FGFR1c antagonism. Hypothalamic thyroid hormone availability is controlled by deiodinase enzymes (DIO2 and DIO3) expressed in tanycytes and is the key regulator of seasonal cycles of energy balance [3 and 4]. Therefore, we determined the effect of IMC-H7 on hypothalamic expression of these deiodinase enzymes. The reductions in food intake and body weight were always associated with decreased expression of DIO2 in the hypothalamic ependymal cell layer containing tanycytes. These data provide further support for the notion the tanycytes are an important component of the mechanism by which the hypothalamus integrates central and peripheral signals to regulate energy intake and expenditure

Platelet activation attracts a subpopulation of effector monocytes to sites of Leishmania major infection

Leishmania infection triggers the recruitment of Gr1+ monocytes to the site of infection via platelet-derived PDGF and subsequent CCL2 production

Novel Pathway of Adipogenesis through Cross-Talk between Adipose Tissue Macrophages, Adipose Stem Cells and Adipocytes: Evidence of Cell Plasticity

INTRODUCTION: Previous studies highlight a complex relationship between lineage and phenotype for adipose tissue macrophages (ATMs), adipose stem cells (ASCs), and adipocytes, suggesting a high degree of plasticity of these cells. In the present study, using a novel co-culture system, we further characterized the interaction between ATMs, ASCs and adipocytes. RESEARCH DESIGN AND METHODS: Human adipocytes and the stromal vascular fraction containing ATMs and ASCs were isolated from human adipose tissue and co-cultured for 24 hours. FACS was used to characterize ATMs and ASCs before and after co-culture. Preadipocytes generated after co-culture were characterized by immunostaining for DLK (preadipocytes), CD14 and CD68 (ATMs), CD34 (ASCs), and Nile Red staining for lipid drops. qRT-PCR was used to quantify adipogenic markers such as C/EBPα and PPARγ. A novel fluorescent nanobead lineage tracing method was utilized before co-culture where fluorescent nanobeads were internalized by CD68 (+) ATMs. RESULTS: Co-culture of adipocytes with ATMs and ASCs increased the formation of new preadipocytes, thereby increasing lipid accumulation and C/EBPα and PPARγ gene expression. Preadipocytes originating after co-culture were positive for markers of preadipocytes, ATMs and ASCs. Moreover, fluorescent nanobeads were internalized by ATMs before co-culture and the new preadipocytes formed after co-culture also contained fluorescent nanobeads, suggesting that new preadipocytes originated in part from ATMs. The formation of CD34(+)/CD68(+)/DLK (+) cell spheres supported the interaction of ATMs, ASCs and preadipocytes. CONCLUSIONS: Cross-talk between adipocytes, ATMs and ASCs promotes preadipocyte formation. The regulation of this novel adipogenic pathway involves differentiation of ATMs to preadipocytes. The presence of CD34(+)/CD68(+)/DLK(+) cells grouped in spheres suggest that paracrine interactions between these cell types plays an important role in the generation and proliferation of new preadipocytes. This phenomenon may reflect the in vivo plasticity of adipose tissue in which ATMs play an additional role during inflammation and other disease states. Understanding this novel pathway could influence adipogenesis, leading to new treatments for obesity, inflammation, and type 2 diabetes

Oceanic and terrestrial sources of continental precipitation

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Reviews of Geophysics 50 (2012): RG4003, doi:10.1029/2012RG000389.The most important sources of atmospheric moisture at the global scale are herein identified, both oceanic and terrestrial, and a characterization is made of how continental regions are influenced by water from different moisture source regions. The methods used to establish source-sink relationships of atmospheric water vapor are reviewed, and the advantages and caveats associated with each technique are discussed. The methods described include analytical and box models, numerical water vapor tracers, and physical water vapor tracers (isotopes). In particular, consideration is given to the wide range of recently developed Lagrangian techniques suitable both for evaluating the origin of water that falls during extreme precipitation events and for establishing climatologies of moisture source-sink relationships. As far as oceanic sources are concerned, the important role of the subtropical northern Atlantic Ocean provides moisture for precipitation to the largest continental area, extending from Mexico to parts of Eurasia, and even to the South American continent during the Northern Hemisphere winter. In contrast, the influence of the southern Indian Ocean and North Pacific Ocean sources extends only over smaller continental areas. The South Pacific and the Indian Ocean represent the principal source of moisture for both Australia and Indonesia. Some landmasses only receive moisture from the evaporation that occurs in the same hemisphere (e.g., northern Europe and eastern North America), while others receive moisture from both hemispheres with large seasonal variations (e.g., northern South America). The monsoonal regimes in India, tropical Africa, and North America are provided with moisture from a large number of regions, highlighting the complexities of the global patterns of precipitation. Some very important contributions are also seen from relatively small areas of ocean, such as the Mediterranean Basin (important for Europe and North Africa) and the Red Sea, which provides water for a large area between the Gulf of Guinea and Indochina (summer) and between the African Great Lakes and Asia (winter). The geographical regions of Eurasia, North and South America, and Africa, and also the internationally important basins of the Mississippi, Amazon, Congo, and Yangtze Rivers, are also considered, as is the importance of terrestrial sources in monsoonal regimes. The role of atmospheric rivers, and particularly their relationship with extreme events, is discussed. Droughts can be caused by the reduced supply of water vapor from oceanic moisture source regions. Some of the implications of climate change for the hydrological cycle are also reviewed, including changes in water vapor concentrations, precipitation, soil moisture, and aridity. It is important to achieve a combined diagnosis of moisture sources using all available information, including stable water isotope measurements. A summary is given of the major research questions that remain unanswered, including (1) the lack of a full understanding of how moisture sources influence precipitation isotopes; (2) the stationarity of moisture sources over long periods; (3) the way in which possible changes in intensity (where evaporation exceeds precipitation to a greater of lesser degree), and the locations of the sources, (could) affect the distribution of continental precipitation in a changing climate; and (4) the role played by the main modes of climate variability, such as the North Atlantic Oscillation or the El Niño–Southern Oscillation, in the variability of the moisture source regions, as well as a full evaluation of the moisture transported by low-level jets and atmospheric rivers.Luis Gimeno would like to thank the Spanish Ministry of Science and FEDER for their partial funding of this research through the project MSM. A. Stohl was supported by the Norwegian Research Council within the framework of the WATER‐SIP project. The work of Ricardo Trigo was partially supported by the FCT (Portugal) through the ENAC project (PTDC/AAC-CLI/103567/2008).2013-05-0

Rab18 and a Rab18 GEF complex are required for normal ER structure

The ancestral Rab GTPase Rab18 and both subunits of the Rab3GAP complex are mutated in the human neurological and developmental disorder Warburg Micro syndrome. Here, we demonstrate that the Rab3GAP complex is a specific Rab18 guanine nucleotide exchange factor (GEF). The Rab3GAP complex localizes to the endoplasmic reticulum (ER) and is necessary for ER targeting of Rab18. It is also sufficient to promote membrane recruitment of Rab18. Disease-associated point mutations of conserved residues in either the Rab3GAP1 (T18P and E24V) or Rab3GAP2 (R426C) subunits result in loss of the Rab18 GEF and membrane-targeting activities. Supporting the view that Rab18 activity is important for ER structure, in the absence of either Rab3GAP subunit or Rab18 function, ER tubular networks marked by reticulon 4 were disrupted, and ER sheets defined by CLIMP-63 spread out into the cell periphery. Micro syndrome is therefore a disease characterized by direct loss of Rab18 function or loss of Rab18 activation at the ER by its GEF Rab3GAP