Temporal Series Analysis Research Articles

Temporal Evolution of Vapor Pressure Deficit Observed in Six Locations of Different Brazilian Ecosystems and Its Relationship with Micrometeorological Variables

In this study, data collected from 2000 to 2019 on vapor pressure deficit (VPD) and its relationship with micrometeorological variables (fire occurrences, aerosol concentration, temperature, and carbon flux) were analyzed in six locations situated in different Brazilian ecosystems: Rio Branco, AC; Manaus, AM; Alta Floresta, MT (within the Amazon Rainforest); Baia das Pedras, MT (Pantanal); Fazenda Miranda, MT (Cerrado); and Petrolina, PE (northeastern semiarid region). Temporal series analysis of VPD was conducted by determining the principal component of singular spectrum analysis (SSA) for this variable in all locations. It was observed that the main component of SSA for VPD is sensitive to local land-use changes, while no evidence of large-scale influences related to global climate change was observed. A strong coupling between VPD values and local maximum temperature with monthly fire occurrence and logarithmic aerosol concentration profiles was also observed. The results of the study are discussed in the context of the ecosystems’ carbon sequestration capacity. The combined results of the study indicate a scenario in which local land-use changes can compromise the capacity of Brazilian ecosystems to absorb carbon.

Temporal Series Analysis of Population Cycle Threshold Counts as a Predictor of Surge in Cases and Hospitalizations during the SARS-CoV-2 Pandemic.

Tools to predict surges in cases and hospitalizations during the COVID-19 pandemic may help guide public health decisions. Low cycle threshold (CT) counts may indicate greater SARS-CoV-2 concentrations in the respiratory tract, and thereby may be used as a surrogate marker of enhanced viral transmission. Several population studies have found an association between the oscillations in the mean CT over time and the evolution of the pandemic. For the first time, we applied temporal series analysis (Granger-type causality) to validate the CT counts as an epidemiological marker of forthcoming pandemic waves using samples and analyzing cases and hospital admissions during the third pandemic wave (October 2020 to May 2021) in Madrid. A total of 22,906 SARS-CoV-2 RT-PCR-positive nasopharyngeal swabs were evaluated; the mean CT value was 27.4 (SD: 2.1) (22.2% below 20 cycles). During this period, 422,110 cases and 36,727 hospital admissions were also recorded. A temporal association was found between the CT counts and the cases of COVID-19 with a lag of 9-10 days (p ≤ 0.01) and hospital admissions by COVID-19 (p < 0.04) with a lag of 2-6 days. According to a validated method to prove associations between variables that change over time, the short-term evolution of average CT counts in the population may forecast the evolution of the COVID-19 pandemic.

Characteristics and in-hospital morbidity trends associated with oral and oropharyngeal cancers in Brazil

BackgroundBrazil experienced an expansion of the population's access to oral health policies after the creation of the Unified Health System (SUS, Sistema Único de Saúde). Through public policies, the consolidation of Primary Health Care (PHC) and the incorporation of dental care into primary and hospital care took place. The objective of this study was to identify epidemiological aspects, including the temporal trend, of hospital morbidity from oral and oropharyngeal cancer in Brazil, considering hospitalizations for this neoplasm in a hospital network linked to the public care system.MethodsObservational study based on information on hospital admissions for oral cancer throughout Brazil. The research used data from the Brazilian Cancer Registry Information System. For the temporal series analysis, generalized linear regression model was used with the Prais-Winsten method.ResultsOf the 121,971 patients hospitalized with oral and oropharyngeal cancers, 76.40% were male and 23.60% were female, resulting in a M:F ratio of 3.24:1. Regarding the anatomical region of involvement among hospitalized patients with oral cavity neoplastic lesions, there was a predominance in non-specific places in the mouth, such as the floor of the mouth, soft and hard palate, among others (32.68%), followed by lesions in the region of tongue (28.89%). In this population, the predominant age group was between the fifth decade (31.09%) and sixth decade of life (24.99%); men presented neoplastic lesions of oral and oropharyngeal cancers at an earlier age than women. In all regions of the country, the staging of cases diagnosed in the tertiary health network accredited to the José Alencar Gomes da Silva National Cancer Institute (INCA) was late, with higher tendency for metastasis. The temporal trend of the adjusted in-hospital morbidity rates showed to be increasing in the Northeast, South and Midwest regions for the male gender. For females, they were increasing in the Northeast and South regions.ConclusionsIt is concluded that the distribution of in-hospital morbidity rates of oral and oropharyngeal cancers in the country is irregular. There is a greater number of cases identified by the study in male patients and in the Southeast and South regions; with an increasing tendency of this coefficient in both genders.

Spatio-temporal surface temperature variations detected by satellite thermal infrared images at Merapi volcano, Indonesia

Merapi volcano is located in central Java and is the most active volcano in Indonesia. Many thousands live on the volcano's flanks which itself is 28 km (17 mi) north of Yogyakarta and its 2.4 million inhabitants. Given this population at risk, and a history of 73 recorded eruptions in the past 500 years, the hazards posed by Merapi are worthy of study. Merapi is monitored by networks of on-site seismology, deformation, and gas emission instruments and, like all volcanoes globally, is also routinely observed by satellite remote sensors. Here, we conduct a temporal and spatial time series analysis of land surface temperature (LST) observations of Merapi, as derived from MODIS (1 km spatial resolution), ASTER (90 m) and Landsat (30 m) thermal infrared imagery. The time series derived from MODIS is decomposed with the Seasonal Trend Decomposition using a Loess (STL) technique and this reveals thermal anomaly peaks caused by the eruptions and a subtle rising tendency in LST since the launch of MODIS in 2000. ASTER surface temperature time series is used for the cross validation of the MODIS LST time series and again, demonstrates thermal anomaly peaks and a longer term upward trend. For a detailed delineation of thermal features at Merapi, the 30 m pixel Landsat thermal imagery derived brightness temperature (BT) distribution during the period from 1988 to 2019 is presented. Finally, change detections (i.e., pixel-by-pixel comparison) of BT distribution from 1988 to 2019 are performed to inspect the spatial temperature variations of Merapi volcano. Positive thermal anomaly areas are identified and these correspond to local heat sources revealed by seismic imaging and resistivity tomography. In summary, the satellite remote sensing approach provides insights into thermal features at a higher spatial and temporal scale than has been conducted in the past and these observations complement ongoing ground-based measurements. The results of this study will feed into both an enhanced understanding of Merapi's thermally anomalous subsurface structures and facilitation of volcano monitoring and hazard assessment.

Management of Regional Natural Resources based on the Variability of Environmental and Economic Indicators

Major ecological problems encourage regional authorities to find a balance between the consumption of natural resources and the preservation of the environment. To this end, we assessed environmental management in three Russian regions (the Ural, Siberian and Far Eastern Federal Districts) in the period 1990–2018 using temporal variability analysis of ecological and economic indicators. Based on the spatial and temporal variability and time series analysis, we developed a methodology for examining the use of natural resources and occurring violations. Temporal variability of environmental and economic indicators was visualised for each type of natural resources (atmospheric, water, forest and land). Additionally, the proposed method allowed us to identify a trend towards balanced environmental management and restoration of regional natural resources over a long period. The variability of environmental and economic indicators of 27 constituent entities of the Russian Federation was analysed based on graphic material. Further, four main groups of these indicators (stable, unstable, homogeneous, and heterogeneous ones) were identified. This typology can be used to determine the leading and outsider regions in terms of the balanced environmental management, indicating its general trend (positive or negative one). Overall, satisfactory and positive environmental management dominate in the examined districts. Simultaneously, negative environmental management (predominance of resource use over their restoration) leads to the adoption of drastic measures to remedy the situation. The obtained results may be useful for developing a methodology to assess environmental and economic indicators of balanced environmental management in regions.

Temporal Series Analysis on Avoidable Mortality for the Assessment of an Intervention Program in a Hospital

Background: Avoidable mortality (AM) is one of the most important health indicators (HI) and represents the quality of care in a hospital.Objective: This study measured the efficacy of a training program for a hospital healthcare staff to reduce AM.Methods: This epidemiological study on community intervention analyzed time-series data on HI by semesters from 2008 to 2015. The pre-intervention phase was examined from January 2008 to December 2014; the intervention phase was investigated in the first semester of 2015; and the post-intervention phase was examined in the second semester of 2015.Results: Resindicate a series with a rising tendency until the 14th semester and a pronounced descent in the 16th semester. The relative variation rate (RVR) was -20% to +20% with some exceptions. HI was 0.53% in the 16th semester rather than the expected 0.70% observed in the pre-intervention phase; therefore, 0.17% additional deaths were avoided because of the training seminar.Conclusion: The positive results suggest that this strategy is an important element in decreasing avoidable deaths in hospitals.

Validation Analysis of SMAP and AMSR2 Soil Moisture Products over the United States Using Ground-Based Measurements

Soil moisture products acquired from passive satellite missions have been widely applied in environmental processes. A primary challenge for the use of soil moisture products from passive sensors is their reliability. It is crucial to evaluate the reliability of those products before they can be routinely used at a global scale. In this paper, we evaluated the Soil Moisture Active/Passive (SMAP) and the Advanced Microwave Scanning Radiometer (AMSR2) radiometer soil moisture products against in situ measurements collected from American networks with four statistics, including the mean difference (MD), the root mean squared difference (RMSD), the unbiased root mean square error (ubRMSE) and the correlation coefficient (R). The evaluation results of SMAP and AMSR2 soil moisture products were compared. Moreover, the triple collocation (TC) error model was used to assess the error among AMSR2, SMAP and in situ data. The monthly average and daily AMSR2 and SMAP soil moisture data were analyzed. Different spatial series, temporal series and combined spatial-temporal analysis were carried out. The results reveal that SMAP soil moisture retrievals are generally better than AMSR2 soil moisture data. The remotely sensed retrievals show the best agreement with in situ measurements over the central Great Plains and cultivated crops throughout the year. In particular, SMAP soil moisture data shows a stable pattern for capturing the spatial distribution of surface soil moisture. Further studies are required for better understanding the SMAP soil moisture product.

Seasonality and trend analysis of tuberculosis in Lahore, Pakistan from 2006 to 2013

Tuberculosis (TB) is a respiratory infectious disease which shows seasonality. Seasonal variation in TB notifications has been reported in different regions, suggesting that various geographic and demographic factors are involved in seasonality. The study was designed to find out the temporal and seasonal pattern of TB incidence in Lahore, Pakistan from 2006 to 2013 in newly diagnosed pulmonary TB cases. SPSS version 21 software was used for correlation to determine the temporal relationship and time series analysis for seasonal variation. Temperature was found to be significantly associated with TB incidence at the 0.01 level with p=0.006 and r=0.477. Autocorrelation function and partial autocorrelation function showed a significant peak at lag 4 suggesting a seasonal component of the TB series. Seasonal adjusted factor showed peak seasonal variation in the second quarter (April–June). The expert modeler predicted the Holt–Winter’s additive model as the best fit model for the time series, which exhibits a linear trend with constant (additive) seasonal variations, and the stationary R2 value was found to be 0.693. The forecast shows a declining trend with seasonality. A significant temporal relation with a seasonal pattern and declining trend with variable amplitudes of fluctuation was observed in the incidence of TB.

Moving Sources Detection Algorithm for Radiation Portal Monitors Used in a Linear Network

To monitor radioactivity passing through a vehicle such as a pedestrian, a car, a train or a truck, Radiation Portal Monitors (RMP) are commonly employed. These detection systems consist of a large volume detector set close to the potential source path. An alarm is then triggered when the signal rises over a threshold initially estimated in view of the natural background signal. The approach developed in this work makes use of several detectors in a network along the source path. The correlation detection approach is elaborated to take into account the temporal periodicity of the signals taken by all distributed sensors as a whole. This new detection method is then not based only on counting statistics but also on the temporal series analysis. Therefore, a specific algorithm has been developed in our laboratory for this security application and shows a significant improvement, especially in terms of detection probability increase and false alarm reduction. This paper presents the theoretical approach and promising results obtained by simulation.

Measuring diversity: looking for processes that generate diversity

In this study, we compare the variations of Margalef K and Shannon H diversity indices obtained for a fish community that suffered changes as a consequence of the impoundment of the upper Tocantins River in Goiás, Brazil. The analysis of different sites along the study area showed that the Shannon index was not sensitive to the environmental changes, whereas the Margalef K index varied significantly following the impoundment. Therefore, the Margalef K index appears to be a good diversity indicator as well as a valuable parameter for the temporal data series analysis, from changing environments and for the conservation of natural environments. Although the Margalef K index can be used as a diversity index, it can also be used to consistently indicate the speed of ecosystem evolution.

Espaços livres e forma urbana: interpretando características e conflitos em Florianópolis (SC)

Florianopolis, according to the IBGE, is among the cities of Santa Catarina that presents significant population growth. This, due to the migration of people from the interior regions of the state itself and as well as several parts of the country, attracted by the quality of life and employment opportunities arising from the existence of public institutions and the provision of goods and services. Fact confirmed with the increase of approximately 23% of the population in the last decade. Consequently, there has been urbanization processes that affect the morphological structure of the landscape, responsable for considerable spatial conflicts, specially on the system of open spaces. Therefore, this study aims to identify public and private spaces in the city according to the environmental laws of the Brazilian Forest Code and the Master Plan. In addition, space syntax studies were performed, so further information concerning the relations of the environment with the urban pattern and its degree of integration. Complementing the research, temporal series analysis were made identifying producer agents of private and public spaces over the past 75 years. Thus, it can be seen that urban growth, mainly due to property speculation and irregular subdivision process, are among the active agents on shaping the space and, consequently, as generators of conflict.

Variação do Índice de Vegetação por Diferença Normalizada na lagoa Itapeva, litoral norte do Rio Grande do Sul, Brasil, a partir de análise de séries temporais

O objetivo do trabalho foi analisar os padrões de comportamento espaço-temporal dos valores do Índice de Vegetação por Diferença Normalizada (NDVI) na lagoa Itapeva-RS, por meio de imagens Landsat TM5 e ETM+7, compreendendo o período de 1985 a 2010. Para a análise do comportamento espaço-temporal foram utilizadas classes de Índice de Vegetação por Diferença Normalizada (NDVI) e Análise por Séries Temporais (TSA) de imagens. Para validação dos padrões observados foram coletadas amostras de água em seis pontos na lagoa Itapeva para clorofila_a, Totais de Sólidos Suspensos e transparência do disco Secchi. Estes resultados foram correlacionados com os valores de NDVI. Os mapas de classes de NDVI gerados após a análise da TSA evidenciaram padrões de dinâmica espaciais e sazonais associados as variáveis ambientais atuantes, permitindo o estabelecimento de três grandes compartimentos para a lagoa Itapeva: norte, centro e sul. A análise da série temporal de imagens mostra que o aumento e o decréscimo dos valores de NDVI estão associados aos períodos de floração do fitoplâncton. Concluiu-se que a análise da Série Temporal de imagens Landsat foi satisfatória no que se refere ao comportamento espaço-temporal da variação das classes de NDVI.

CHAOS VIA FRACTALITY IN GRAVITATIONAL SYSTEMS DYNAMICS: A NEW APPROACH (I)

The neutral particle motion in a composite field (gravitoelectromagnetic field overlapping a constant external gravitomagnetic field) is analyzed. A detailed nonlinear dynamics description, using temporal series, Poincaré sections, phase space, Lyapunov exponents, bifurcation diagrams and fractal analysis, is performed. New phenomena, e.g. the gravitational gun-type, gravitational chaotic gun-type and gravitational multigun-type effects are discovered, if the amplitude of the gravitoelectromagnetic field is sufficiently large. These effects induce a high acceleration of the neutral particles which lead to sudden jumps between different Larmor-type orbits. It results both in a chaotic behavior and patterns formation in gravitational systems.

Enhanced Vegetation Index (EVI) na análise da dinâmica da vegetação da reserva biológica de Sooretama, ES

Técnicas de análises de séries temporais são utilizadas para caracterizar o comportamento de fenômenos naturais no domínio do tempo. Neste artigo, segundo a metodologia proposta por Box et al. (1994), 125 observações do Enhanced Vegetation Index (EVI) foram analisadas. Os valores modelados correspondem às variações temporais ocorridas no dossel florestal da reserva biológica de Sooretama, localizada ao Norte do Estado do Espírito Santo, no Município de Linhares. Os resultados indicaram que a metodologia foi adequada. Os resíduos do modelo ajustado são não correlacionados com distribuição normal, média zero e variância s². Com o menor valor do Critério de Informação de Akaike (AIC) -570,51, o modelo ajustado foi o Sazonal Auto-Regressivo Integrado de Médias Móveis (1,0,1)(1,0,1)12.

Spatial variability and temporal change of water discharge and sediment flux in the Lower Jinsha tributary: impact of environmental changes

AbstractAnalysis of water discharge and sediment flux data as measured in the Longchuanjiang Basin in the Lower Jinsha tributary over the past few decades has been undertaken. The results of this study indicate that the lower reaches of the Longchuanjiang River produce relatively less runoff but higher sediment loads than the upper reaches. This can be attributed to the differences in climate, the dissected terrain and the sparse vegetation cover of the downstream river. Temporal series analysis suggests a significant increase in sediment flux, notably in the lower reaches of the river. The available data suggest the increasing sediment flux is a result of climate variations and a series of human activities such as land‐use changes, mainly through deforestation and agricultural expansion. Other activities, such as road construction, urban expansion, building‐material excavation and large‐scale terrace construction and afforestation, have also contributed to the significant increase in the sediment flux. However, the Longchuanjiang Basin as a whole has a low sediment yield (&lt; 1000 t km−2 a−1), despite severe soil erosion in the catchment. This is a result of sediment deposition in the numerous reservoirs, constructed since the 1950s. Runoff in the dry season has also significantly declined due to increasing water consumption. These profound changes in the hydrological regime will have significant implications for effective soil erosion and water management. Further studies in the region are necessary to address the impact of these human activities on hydro‐geomorphological processes and, particularly, water discharge and sediment flux. Copyright © 2005 John Wiley &amp; Sons, Ltd.

Contribuição ao estudo da desertificação na Bacia do Taperoá

O fenômeno da desertificação na região semi-árida do Nordeste do Brasil é estudado a partir da análise de variáveis representativas do clima, vegetação, solos e aspectos socioeconômicos na bacia hidrográfica do Taperoá, no Estado da Paraíba - Brasil. As séries temporais da precipitação anual de 32 pluviômetros foram examinadas e um mapa de tendência da pluviosidade anual foi traçado. As variáveis mencionadas acima são estimadas para os municípios de São João do Cariri e Cabaceiras, respectivamente. Os resultados mostram, de modo diferenciado para os dois municípios, a susceptibilidade à desertificação. No primeiro município, todas as variáveis analisadas contribuem para afirmar que um processo bastante significativo de desertificação está em curso, inclusive associado a uma diminuição das precipitações anuais.

Temporal series analysis approach to spectra of complex networks.

The spacing of nearest levels of the spectrum of a complex network can be regarded as a time series. Joint use of the multifractal detrended fluctuation approach (MF-DFA) and diffusion entropy (DE) is employed to extract characteristics from this time series. For the Watts-Strogatz small-world model, there exists a critical point at rewiring probability P(r) =0.32. For a network generated in the range 0< P(r) <0.32, the correlation exponent is in the range of 1.0-1.64. Above this critical point, all the networks behave similar to that at p(r) =1. For the Erdos-Renyi model, the time series behaves like fractional Brownian motion noise at p(ER) =1/N. For the growing random network (GRN) model, the values of the long-range correlation exponent are in the range of 0.74-0.83. For most of the GRN networks the probability distribution function of a constructed time series obeys a Gaussian form. In the joint use of MF-DFA and DE, the shuffling procedure in DE is essential to obtain a reliable result.

Population dynamics using temporal series analysis in a industrial two-stage activated sludge pilot plant

A time series analysis using an autocorrelation function (ACF) was used to assess the relative importance of density (DD) and non density-dependent - (NDD) factors on microfauna abundance of a two-stage activated sludge pilot plant treating industrial effluents. Although some previous work has detected a carrying capacity for the total microfauna abundance in both reactors, ACF showed a general pattern of non-density dependent abundance regulation. Stationarity due to density-dependent factors was observed for the two major species in the first reactor, the sessile Opercularia asymmetrica and the crawling Chilodonatella minuta. There was no evidence of bacterial competition and only weak evidence of floc surface competition. It is possible that the main driving factor in the first reactor was the constant wasting rate. In the second reactor, the microfauna was clearly dependent on substrate fluctuations, attaining densities one order of magnitude higher than in the first reactor. This was probably a consequence of its longer sludge age. An 8-day oscillation period was detected only in the first reactor, while a second oscillation of about 30 days was observed in both the first and second reactors. ACF was shown to be a simple method for discriminating between DD and NDD factors influencing species and total abundance dynamics.

Population dynamics using temporal series analysis in a industrial two-stage activated sludge pilot plant

A time series analysis using an sutocorrelation function (ACF) was used to assess the relative importance of density (DD) and non density-dependent - (NDD) factors on microfauna abundance of a two-stage activated sludge pilot plant treating industrial effluents. Although some previous work has detected a carrying capacity for the total microfauna abundance in both reactors, ACF showed a general pattern of non-density dependent abundance regulation. Stationarity due to density-dependent factors was observed for the two major species in the first reactor, the sessile Opercularia asymmetrica and the crawling Chilodonatella minuta. There was no evidence of bacterial competition and only weak evidence of floc surface competition. It is possible that the main driving factor in the first reactor was the constant wasting rate. In the second reactor, the microfauna was clearly dependent on substrate fluctuations, attaining densities one order of magnitude higher than in the first reactor. This was probably a consequence of its longer sludge age. An 8-day oscillation period was detected only in the first reactor, while a second oscillation of about 30 days was observed in both the first and second reactors. ACF was shown to be a simple method for discriminating between DD and NDD factors influencing species and total abundance dynamics.

The Taylor-Green vortex and fully developed turbulence

We here report results obtained from numerical simulations of the TaylorGreen three-dimensional vortex flow. This flow is perhaps the simplest system in which one can study the generation of small scales by three-dimensional vortex stretching and the resulting turbulence. The problem is studied by both direct spectral numerical solution of the Navier-Stokes equations (with up to 2563 modes) and by power series analysis in time. The inviscid dynamics are strongly influenced by symmetries which confine the flow to an impermeable box with stress-free boundaries. There is an early stage during which the flow is strongly anisotropic with well-organized (laminar) small-scale excitation. The flow is smooth but has complex-space singularities within a distanceδ(t) of the real space which are manifest through an exponential tail in the energy spectrum. It is found thatδ(t) decreases exponentially in time to the limit of our resolution. Indirect evidence is presented that more violent vortex stretching takes place at later times, possibly leading to a real singularity (δ=0) at a finite time. These direct integration results are consistent with new presented results extending the Morf, Orszag, and Frisch temporal power series analysis from order t40 to order t80. Still, convincing evidence for or against the existence of a real singularity will require even more sophisticated analysis. The viscous dynamics (decay) have been studied for Reynolds numbersR (based on integral scale) up to 3000 and beyond the time tmax at which the maximum energy dissipation is achieved. Early time, highR dynamics are essentially inviscid and laminar. Then, instabilities starting at small scales, which may be driven by viscosity, make the flow increasingly chaotic (turbulent) with extended high-vorticity patches appearing away from the impermeable walls. Neart max the small scales of the flow are nearly isotropic providedR>1000. Various features characteristic of fully developed turbulence are observed neart max whenR=3000.