Subspace tracking for independent phase noise source separation in frequency combs

Advanced digital signal processing techniques in combination with ultra-wideband balanced coherent detection have enabled a new generation of ultra-high speed fiber-optic communication systems, by moving most of the processing functionalities into digital domain. In this paper, we demonstrate how digital signal processing techniques, in combination with ultra-wideband balanced coherent detection can enable optical frequency comb noise characterization techniques with novel functionalities. We propose a measurement method based on subspace tracking, in combination with multi-heterodyne coherent detection, for independent phase noise sources identification, separation and measurement. Our proposed measurement technique offers several benefits. First, it enables the separation of the total phase noise associated with a particular comb-line or -lines into multiple independent phase noise terms associated with different noise sources. Second, it facilitates the determination of the scaling of each independent phase noise term with comb-line number. Our measurement technique can be used to: identify the most dominant source of phase noise; gain a better understanding of the physics behind the phase noise accumulation process; and confirm, already existing, and enable better phase noise models. In general, our measurement technique provides new insights into noise behavior of optical frequency combs

Lifshitz transition enabling superconducting dome around the quantum critical point in TiSe2_2

Superconductivity often emerges as a dome around a quantum critical point (QCP) where long-range order is suppressed to zero temperature. So far, this has been mostly studied in magnetically ordered materials. By contrast, the interplay between charge order and superconductivity at a QCP is not fully understood. Here, we present resistance measurements proving that a dome of superconductivity surrounds the charge-density-wave (CDW) QCP in pristine samples of 1$T$-TiSe$_2$ tuned with hydrostatic pressure. Furthermore, we use quantum oscillation measurements to show that the superconductivity sets in at a Lifshitz transition in the electronic band structure. We use density functional theory to identify the Fermi pockets enabling superconductivity: large electron and hole pockets connected by the CDW wave vector $\vec{Q}$ which emerge upon partial suppression of the zero-pressure CDW gap. Hence, we conclude that superconductivity is of interband type enabled by the presence of hole and electron bands connected by the CDW $\vec{Q}$ vector. Earlier calculations show that interband interactions are repulsive, which suggests that unconventional s$_{\pm}$ superconductivity is realised in TiSe$_2$ - similar to the iron pnictides. These results highlight the importance of Lifshitz transitions in realising unconventional superconductivity and help understand its interaction with CDW order in numerous materials.Comment: 21 pages, 5 figure

A method for verifying the uniformity in fertilizer dispenser flow

The success of crops is directly related to effective planting and fertilization, especially regarding yield factors like plants per area and final yield. Thorough evaluations are vital to understanding modern methods in these operations. Current regulations and their broaden scope highlight the need for more specific approaches. This study aimed to validate a new method for assessing the effectiveness of helical and fluted dosing mechanisms with two granulated fertilizer formulations (04-14-08 [GF1] and 04-30-10 [GF2]) at different speeds (4, 7, and 10 km/h) in a controlled setting. We collected flow data, organized it, checked for normality, and subjected it to variance analysis. The fluted dispenser showed better flow at 4 km/h and 7 km/h. The GF1 formulation produced higher flows in both dispensers, with the helical design outperforming. The flow for GF1 increased linearly with speed. For GF2, the best flow rate was at 7 km/h. In summary, our new method effectively evaluated the factors under study, offering insights into the function and potential improvements of the technologies used

Phylogenetic identification of marine bacteria isolated from deep-sea sediments of the eastern South Atlantic Ocean

The deep-sea environments of the South Atlantic Ocean are less studied in comparison to the North Atlantic and Pacific Oceans. With the aim of identifying the deep-sea bacteria in this less known ocean, 70 strains were isolated from eight sediment samples (depth range between 1905 to 5560 m) collected in the eastern part of the South Atlantic, from the equatorial region to the Cape Abyssal Plain, using three different culture media. The strains were classified into three phylogenetic groups, Gammaproteobacteria, Firmicutes and Actinobacteria, by the analysis of 16s rRNA gene sequences. Gammaproteobacteria and Firmicutes were the most frequently identified groups, with Halomonas the most frequent genus among the strains. Microorganisms belonging to Firmicutes were the only ones observed in all samples. Sixteen of the 41 identified operational taxonomic units probably represent new species. The presence of potentially new species reinforces the need for new studies in the deep-sea environments of the South Atlantic. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2193-1801-2-127) contains supplementary material, which is available to authorized users

Seed sensor position on seeder performance at varying speeds

ABSTRACT: The uniformity of seed distribution and sowing speed directly impact crop quality and productivity. This experiment assessed how the position of the sowing monitoring sensor influences the distribution of cotton seeds using a pneumatic meter at different operating speeds. The experiment employed a completely randomized two-factor factorial design on a static simulation bench. The first factor involved the sensor installation sites (upper, middle, and lower portions of the conductor tube and conveyor belt), while the second factor encompassed simulated speeds of 3.0, 5.0, 7.0, 9.0, and 11.0 km/h. Parameters such as frequency of double, flawed, and acceptable spacing, coefficient of variation, and precision index were measured based on five replications of 250 consecutive spacing. The results indicated that the sensor’s placement significantly influences reading accuracy. Optimal results were observed when the sensor was positioned at the final portion of the conductor tube, providing more accurate seed deposition, and facilitating decision-making

Indo-Brazilian Late Palaeozoic wildfires: an overview on macroscopic charcoal

Carvão vegetal macroscópico é amplamente aceito como um indicador direto da ocorrência de paleo-incêndios vegetacionais, sendo relativamente bem estudado e distribuído de forma homogênea em depósitos do Paleozoico Superior da Euramérica e Cataísia. Por outro lado, apenas alguns registros deste tipo de material foram publicados para o Paleozoico Superior do Gondwana e, somente recentemente foi demonstrado que carvão vegetal macroscópico (e, portanto, incêndios) também é comum no continente meridional. Os mais importantes registros do Gondwana se constituem em fragmentos carbonizados de lenhos gimnospérmicos e estão associados, principalmente, a depósitos de carvão mineral. Registros de macro-charcoal (carvão vegetal macroscópico) foram descritos para níveis do Paleozoico Superior da Bacia Damodar (Índia) e da Bacia do Paraná (Brasil), demonstrando que paleo-incêndios vegetacionais ocorriam em sequências e intervalos estratigráficos variados no Gondwana durante esse período. Com base nos registros publicados até o momento e em novos exemplares provenientes do nível de carvão Seam-IV, Formação Raniganj, Bacia Damodar (Lopingiano da Índia), uma revisão acerca dos registros indo-brasileiros de carvão vegetal macroscópico em níveis do Paleozoico Superior são apresentados. O material inédito foi analisado sob Microscópio Eletrônico de Varredura para a definição de características anatômicas, sendo estabelecida uma afinidade gimnospérmica para os fragmentos. Os dados apresentados reforçam a importância dos paleo-incêndios vegetacionais como elemento perturbador dos diferentes paleoambientes gondvânicos durante o Paleozoico Superior.Sedimentary charcoal is widely accepted as a direct indicator for the occurrence of paleo-wildfires and, in Upper Paleozoic sediments of Euramerica and Cathaysia, reports on such remains are relatively common and (regionally and stratigraphically) more or less homogeneously distributed. On the contrary, just a few reliable records have been published for the Late Paleozoic of Gondwana and only recently it has been demonstrated that macroscopic charcoals (and thus fires) were also common in the southern continent during this period. The most important Gondwanan records are predominantly charred gymnosperm woods mainly related to coal bearing strata. Late Paleozoic macro-charcoal occurs in both, the Damodar Basin (India) and the Paraná Basin (Brazil), demonstrating that paleo-wildfires were spread out in different sequences and distinct stratigraphic intervals during this period in Gondwana. Based on the so far published records as well as new samples from the Seam-VI coalfield, Raniganj Formation (Damodar Basin – Lopingian of India), an overview of the Late Paleozoic Indo‑Brazilian macro-charcoal remains is presented. The hitherto unpublished samples were anatomically analyzed under Scanning Electron Microscope and a gymnosperm affinity could be established. The data presented here reinforce the relevance of paleo-wildfire as a source of environmental disturbance over large areas of Gondwana during the Late Paleozoic

The Deep Water Abundance on Jupiter: New Constraints from Thermochemical Kinetics and Diffusion Modeling

We have developed a one-dimensional thermochemical kinetics and diffusion model for Jupiter's atmosphere that accurately describes the transition from the thermochemical regime in the deep troposphere (where chemical equilibrium is established) to the quenched regime in the upper troposphere (where chemical equilibrium is disrupted). The model is used to calculate chemical abundances of tropospheric constituents and to identify important chemical pathways for CO-CH4 interconversion in hydrogen-dominated atmospheres. In particular, the observed mole fraction and chemical behavior of CO is used to indirectly constrain the Jovian water inventory. Our model can reproduce the observed tropospheric CO abundance provided that the water mole fraction lies in the range (0.25-6.0) x 10^-3 in Jupiter's deep troposphere, corresponding to an enrichment of 0.3 to 7.3 times the protosolar abundance (assumed to be H2O/H2 = 9.61 x 10^-4). Our results suggest that Jupiter's oxygen enrichment is roughly similar to that for carbon, nitrogen, and other heavy elements, and we conclude that formation scenarios that require very large (>8 times solar) enrichments in water can be ruled out. We also evaluate and refine the simple time-constant arguments currently used to predict the quenched CO abundance on Jupiter, other giant planets, and brown dwarfs.Comment: 42 pages, 7 figures, 4 tables, with note added in proof. Accepted for publication in Icarus [in press

Design for production of a children’s house in light wood frame

Para edificações estruturadas em madeira são necessários projetos bem detalhados, com etapas e especialidades relacionadas e dependentes entre si. Seu projeto para produção deve ocorrer simultaneamente ao projeto arquitetônico. O projeto para produção de edificações do tipo wood frame pode contribuir para uma disseminação de qualidade. Este artigo tem como objetivo apresentar o caso de um projeto para produção desenvolvido para uma casinha para crianças constituída com o sistema wood frame. As principais etapas do método aplicado foram: (1) dividir a edificação em painéis de piso, parede e cobertura; (2) detalhar os componentes constituintes de cada painel; (3) locar os painéis na sua posição para a montagem final. Os resultados apresentam desenhos e tabelas desenvolvidos para a manufatura dos elementos pré-fabricados e sua montagem final no canteiro. Neste caso, observou-se que a padronização e a identificação dos componentes facilitaram na execução, evitando retrabalhos e agilizando o processo.For wooden structures, the design must comprehend many details, including execution stages and related interdependent specialties. The design for production must occur simultaneously with the architectural design. The design for production of wood frame buildings may contribute to a quality dissemination. This article aims to present a case of a design for production developed for a children's house constituted with the wood frame system. The main steps of the method applied were: (1) divide the building into floor, wall and roof panels; (2) detail the components of each panel; (3) place the panels in their position for final assembly. The results present drawings and tables developed for the manufacture of prefabricated elements and their final assembly at the construction site. In this case, it was observed that the standardization and identification of the components facilitated the execution, avoiding rework and streamlining the process

Dez anos do curso de agronomia da UFFS: o que mostram os índices de permanência e evasão estudantil

Challenges, overcoming, weaknesses and achievements permeate the academic path of undergraduate students. In 2019, the Agronomy course at the Federal University of Fronteira Sul (UFFS), completed ten years of training, which makes it possible to evaluate this path and consider about its continuity. Therefore, this article aims to analyze the permanence and dropout rates in Agronomy courses at UFFS. The adopted methodology was based on documents’ analysis that guided the offering of the course and on calculation of permanence and dropout rates, according to each campi they are offered. For this calculation, the “flow” or “student follow-up” method was chosen. The observed predictors pointed out requirements to advance on permanence, retention and evasion studies, within the scope of the course, integrating actions and strategies to identify management practices that are effective in mitigating the problem and presenting increasingly satisfactory results.O percurso acadêmico dos estudantes de graduação é permeado de desafios, de superações, de fraquezas e de conquistas. Em 2019, o curso de Agronomia da Universidade Federal da Fronteira Sul (UFFS) completou dez anos de ação formativa, o que oportunizou avaliar esse percurso e pensar na sua continuidade. Sendo assim, este artigo tem como objetivo analisar os índices de permanência e evasão no curso de Agronomia da UFFS. A metodologia adotada baseou-se na análise dos documentos que norteiam a oferta do curso e no cálculo dos índices de permanência e de evasão de acordo com os campi em que são ofertados. Para esse cálculo, optou-se pelo método “de fluxo”, ou “de acompanhamento de estudantes”. Os indicadores observados apontam para a necessidade de avançar nas discussões sobre a permanência, a retenção e a evasão no âmbito do curso, integrando ações e estratégias para identificar práticas de gestão que se mostrem mais efetivas para mitigar o problema, bemcomo apresentar resultados cada vez mais satisfatórios