annual periodicity
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2021 ◽  
Vol 880 (1) ◽  
pp. 012001
Author(s):  
Y Rivera ◽  
K C Capacete ◽  
S K Rodriguez ◽  
A R David ◽  
E Macalalad

Abstract Precipitable Water Vapor (PWV) refers to the content of water vapor in the atmosphere which is significant in observing climate changes. The trends and variations of precipitable water vapor in Laoag, Legazpi, Mactan, and Puerto Princesa from 2012-2019, are presented through the use of radiosonde data derived from the database of the Integrated Global Radiosonde Archives (IGRA). These data were analyzed for possible patterns through a time series of its daily, monthly, and annual mean, together with a Lomb-Scargle periodogram, and Mann-Kendall test. The results observed varying trends and variability. Legazpi and Puerto Princesa with a minimum value of 20 mm, observed a gradual downward trend of PWV. Laoag and Mactan detected an upward trend of PWV with a minimum of 10 mm and 20 mm, respectively. It also showed an annual and bi-annual periodicity of PWV. Furthermore, all cities detected an increase of PWV during the wet months of May to September, while the dry months of October to April with slight variations over 8 years. In terms of seasonality, only Laoag observed a slightly different dry season, with January, February, and March experiencing around 5 mm less in monthly PWV variation compared to the other cities. The correlation of surface temperature and relative humidity of PWV observed an overall increasing trend while showing a general moderate positive correlation. This study can be used for future references for meteorologists for upcoming forecasting on the likelihood of different weather phenomena in the Philippines.


2021 ◽  
Vol 10 (15) ◽  
pp. 3224
Author(s):  
August Wrotek ◽  
Artur Badyda ◽  
Piotr O. Czechowski ◽  
Tomasz Owczarek ◽  
Piotr Dąbrowiecki ◽  
...  

Respiratory syncytial virus (RSV) contributes significantly to pediatric hospitalizations. An association between air pollution and an increased number of RSV cases has been suggested. We sought to evaluate the short-term impact of air pollutants on RSV hospitalizations in Polish children in the period 2010–2019. Daily concentrations of PM10 and PM2.5 (particulate matter with an aerodynamic diameter less than or equal to 10 μm and 2.5 μm, respectively) and nitrogen dioxide (NO2) were analyzed in general regression models (GRM) to establish their influence and full interaction scheme. Significant seasonal and annual periodicity among 53,221 hospitalizations was observed; finally, data from the 2012–2019 RSV high-risk seasons created models for seven agglomerations. The addition of PM2.5, PM10, and NO2 to the basic model for RSV seasonality explained 23% (4.9–31%, univariate model) to 31.4% (8.4–31%, multivariate model) of the variance in RSV hospitalizations. A 10 μg/m3 increase in PM2.5, PM10, and NO2 concentrations was associated with 0.134 (0.087–0.16), 0.097 (0.031–0.087), and 0.212 (0.04–0.29) average increases in hospitalizations, respectively. In the multivariate models, PM2.5, PM10, and NO2 alone, as well as PM2.5–NO2, PM2.5–PM10, and PM10–NO2 interactions, were associated with hospitalizations in some of the locations, while the metaregression showed statistically significant interactions between each of the pollutants, and between the pollutants and the year of the study. The inclusion of PM2.5, PM10, and NO2 in GRM explains a significant number of RSV hospitalizations. The pollutants act alone and interact together in a varied manner. Reducing air contamination might decrease the costs of hospital healthcare.


2021 ◽  
Author(s):  
Josef Vlcek ◽  
Roman Beránek ◽  
Tomáš Fischer

<p>In past decades, a significant effort was spent to find the origin of recurring earthquake swarms in West-Bohemia/Vogtland. Widespread understanding accepts that crustal fluids migration along the fault zones is responsible for earthquake triggering in this area. Recently, a new model was suggested, which tests the hypothesis whether the diffusion of hydraulically induced pore pressure could be a valid trigger mechanism. In this approach the precipitation signal was transformed by diffusion equation to the hypocenter depth and statistically compared with the earthquake occurrence in time and concluded that at least 19% of the seismicity could have been triggered by rain. </p><p>In our study we apply a different approach to verify the validity of these results. We use two types of rain signal on the input which is compared with the time series of earthquake weekly rate for the past 25 years. To remove the strong episodic character of the swarm seismicity we use a declustered seismic catalog, which is characteristic by almost continuous seismic activity.</p><p>The rain signal is represented first by the precipitation data and second by the water level data in the Horka reservoir, which is located above the main focal zone of Nový Kostel. We test the possible relation to the earthquake swarm activity by cross correlating both the rain signal types and the seismicity rate. To amplify the possible seasonal periodicity of the data we stacked the explored time series data (precipitation, water level and seismic activity) according to their occurrence date in a single year. The results show that in any of the input data and seismicity do not correlate. </p><p>In the next step, we tested the possible (annual) periodicity of the data in question by the singular spectral analysis (SSA), which is a sensitive method to identify possible periodic signals in the presence of noise. While the water level data showed a striking peak for the period of 1 year, any indication of annual periodicity was never found in the seismicity data. Accordingly, we conclude that our analysis has shown no influence of the precipitation or the water level fluctuations in the Horka dam to the earthquake swarm activity in West Bohemia/Vogtland.</p>


2021 ◽  
Vol 19 (2) ◽  
Author(s):  
Leandro Balboni ◽  
Facundo Vargas ◽  
Darío Colautti

Abstract The age and growth of Pseudoplatystoma corruscans, is analyzed on specimens landed in Puerto Antequera, Province of Chaco, Argentina. The study is based on length frequency distribution of 1192 individuals and growth marks of 293 pectoral spines. Previously to age assignation based on spines readings, we performed analyses that ruled out age-associated resorption of rings and corroborated the annual periodicity of mark formation. The average sizes of the radius of each ring were obtained, and the total length of fish were back-calculated to the time of the ring formation, by the regression model fitted between the total radius of the spines to the respective sizes of each fish. Such data showed a good fitting to growth models of von Bertalanffy, Gompertz and logistic for both sexes separately. Results indicate that the study of the species growth must be carried out for each sex separately and that the fishing regulations must consider this characteristic of the species since the current management guidelines could be promoting differential capture by sexes.


2020 ◽  
Vol 68 (4) ◽  
Author(s):  
Luz Carrillo ◽  
Rafael Tavares ◽  
Leonardo Sánchez ◽  
Carmen Velásquez

Abstract. Introduction: Mustelus higmani is one of the shark species most commonly caught in the northeastern region of Venezuela; however, this species has been poorly studied. Objective: to evaluate the age and growth of M. higmani on the basis of the optical analysis of vertebrae. Methods: Between August 2016 and July 2017, the vertebral samples were collected in the fishing port of Juan Griego, Margarita Island. The growth study was based on a sample of 238 individuals, 86 males (24.1-59.5 cm TL) and 152 females (24.4-69.5 cm TL) and the use of growth modeling approaches. Results: The RMI analysis indicated an annual periodicity for the deposition of growth rings. Ages assigned varied between 0 and 5 years in males, and between 0 and 6 years in females. The estimates of growth parameters obtained were L∞ = 60.8 cm TL, k = 0.54 years-1 and t0 = -1.04 years in males; and L∞ = 72.4 cm TL, k = 0.40 years-1 and t0 = -1.31 years in females. The ages at maturity and longevities resulted respectively in 2.5 and 6.4 years for males; and in 2.0 and 8.7 years for females. Conclusions: In general, results indicate that M. higmani has a rapid growth, early maturity, short longevity, and continuous reproduction, characterizing it as a biologically productive species. Key words: Caribbean; ecology; elasmobranchs; fishery; sharks.


2020 ◽  
Vol 17 (169) ◽  
pp. 20200480
Author(s):  
Alexandre Blake ◽  
Ali Djibo ◽  
Ousmane Guindo ◽  
Nita Bharti

Measles is a major cause of child mortality in sub-Saharan Africa. Current immunization strategies achieve low coverage in areas where transmission drivers differ substantially from those in high-income countries. A better understanding of measles transmission in areas with measles persistence will increase vaccination coverage and reduce ongoing transmission. We analysed weekly reported measles cases at the district level in Niger from 1995 to 2004 to identify underlying transmission mechanisms. We identified dominant periodicities and the associated spatial clustering patterns. We also investigated associations between reported measles cases and environmental drivers associated with human activities, particularly rainfall. The annual and 2–3-year periodicities dominated the reporting data spectrum. The annual periodicity was strong with contiguous spatial clustering, consistent with the latitudinal gradient of population density, and stable over time. The 2–3-year periodicities were weaker, unstable over time and had spatially fragmented clustering. The rainy season was associated with a lower risk of measles case reporting. The annual periodicity likely reflects seasonal agricultural labour migration, whereas the 2–3-year periodicity potentially results from multiple mechanisms such as reintroductions and vaccine coverage heterogeneity. Our findings suggest that improving vaccine coverage in seasonally mobile populations could reduce strong measles seasonality in Niger and across similar settings.


Author(s):  
Omar Saidov

According to the literature, modern ideas about the earthquake center as one of the blocks of the hierarchical structure of the earth's crust, which loses stability during energy and mass exchange with the environment, are considered. Long-term continuous measurements (6 years) of hydrogen concentrations in the surface-atmosphere were carried out at two observation points in the Dagestan wedge tectonic region (Republic of Dagestan). It is shown that variations of hydrogen concentrations in the surface-atmosphere have annual periodicity. At the same time, in adjacent time intervals of the series, a change in the dispersion of hydrogen concentrations is noted. Initially, there is an increase in the value of the dispersion, after which it is marked by an abrupt decrease, the stages of which in most cases correspond to seismic events. A change in the dispersion value in adjacent time intervals of hydrogen concentrations implies a corresponding change in the entropy in the exciting thermodynamic system, i.e. in the earthquake focus. As a result of the relaxation of elastic energy, the thermodynamic system passes to the most probable, steady-state, and accordingly, values of dispersion of concentrations of hydrogen tend to a minimum.


2020 ◽  
Vol 58 ◽  
pp. 101079
Author(s):  
Guaciara M. Santos ◽  
Daniela Granato-Souza ◽  
Ana Carolina Barbosa ◽  
Rose Oelkers ◽  
Laia Andreu-Hayles

Edukasi ◽  
2020 ◽  
Vol 14 (1) ◽  
Author(s):  
- Fakhruddin

KKG as one of Teacher Community expected to improve service quality and educational outcomes. The issues are, how the mechanism of cluster working groups of teachers in improving the quality of learning, whether the potential material and nonmaterial which can be used as a source of development of teachers in the management of learning, and how to support and empowerment of teacher working group in understanding and implementing the curriculum level education units. Data collection was taken by using questionnaire research and documentation. Questionnaires are used to reveal the mechanisms, programs, support and empowerment of KKG. Documentation are used to reveal data about the number of primary schools, learners and Cluster KKG. Results showed that the mechanism of development and management of the KKG is set through consultation according to the annual periodicity, further to enhance competence through sharing knowledge, skills and attitudes, test ideas, and discussion. The results suggest that preparation of KKG program tailored to the needs and problem of teachers in classroom learning, the importance of monitoring and evaluation continues with the instruments and the framework of implementation of SBC by every teacher in class need to attempt- efforts to obtain the support of various parties.


2020 ◽  
Author(s):  
Fakhraddin Gadirov (Kadirov) ◽  
Luciano Telesca ◽  
Gulam Babayev ◽  
Gurban Yetirmishli ◽  
Rafig Safarov

<p>Reservoir-induced seismicity has been studied worldwide due to its potential to provoke damage to buildings and constructions, and, more important, human loss. Reservoir-induced seismicity (RIS) is normally related with additional static loading (the weight of the water reservoir and its seasonal variations), tectonic faults, liquefaction and pore pressure variations.The Mingechevir reservoir is located in the north-west of Azerbaijan on the Kurriver. This water reservoir is extended from north-west towards south-east through Kur river valley by 75 km. The area of the dam is 625 km<sup>2</sup> with the average width accounting for 6-8 km. The volume of the dam is 16 km<sup>3</sup>. The dam filling started in 1953. This reservoir is the largest one in the Caucasus and carries a number of geo-hazards interrelated with geodynamics and technogenic factors. The aim of the present study in the Mingechevir reservoir is to investigate relationship between the fluctuations of the water level and the onset of seismicity in the area around the dam more in detail, by using several and independent statistical methods.The temporal variations of the instrumental seismicity (0.5≤M<sub>L</sub>≤3.5) recorded in the Mingechevir area (Azerbaijan) between January 2010 to April 2018 and its relationship with the level variation of the water reservoir was analysed in this study. Due to the relative high completeness magnitude (M<sub>C</sub> = 1.6) of the seismic catalogue of the area, only 136 events were selected over a period of more than 8 years. Thus, the monthly number of events was analysed by using the correlogram-based periodogram, the singular spectrum analysis (SSA) and the empirical mode decomposition (EMD), which are robust against the short size of the time series. Our results point out to the following findings: 1) annual periodicity was found in one SSA reconstructed component of the monthly number of events; 2)quasi-annual periodicity was found in one EMD intrinsic mode function of the monthly number of earthquakes. These obtained results could support in a rigorously statistical manner that the seismicity occurring in Minghechevir area could be triggered by the yearly cycle of the water level of the reservoir.</p><p> </p><p><strong>Keywords:</strong>water reservoir, induced seismicity, water level change, Mingechevir reservoir, Azerbaijan</p>


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