Analysis of Secular Variations of Geomagnetic Field in Lithuania Based on the Survey in 2016

2017 ◽  
Author(s):  
Arunas Buga ◽  
Simona Einorytė ◽  
Romuald Obuchovski ◽  
Vytautas Puškorius ◽  
Petras Petroškevicius
Keyword(s):  
Geomagnetic Field ◽  
Field Research ◽  
Field Measurements ◽  
Geomagnetic Observatory ◽  
Research Activities ◽  
Secular Variations ◽  
Geomagnetic Data ◽  
The Mean ◽  
Using Data ◽  
Magnetic Field Variations

Lithuania is successfully integrated in the European geomagnetic field research activities. Six secular variation research stations were established in 1999 and precise geomagnetic field measurements were performed there in 1999, 2001, 2004, 2007 and 2016. Obtained diurnal magnetic field variations at measuring station and neighbouring observatories were analysed. All measurements are reduced to the mean of the year using data from geomagnetic observatory of Belsk. Based on the measured data the analysis of geomagnetic field parameter secular changes was performed. Results of the presented research are useful for updating the old geomagnetic data as well as for estimation of accuracy of declination model.

scholarly journals An Adaptive Approach for Voltage Sag Automatic Segmentation

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3519 ◽  
Author(s):  
Xianyong Xiao ◽  
Wenxi Hu ◽  
Huaying Zhang ◽  
Jingwen Ai ◽  
Zixuan Zheng
Keyword(s):  
Automatic Segmentation ◽  
Field Measurements ◽  
Voltage Sag ◽  
Segmentation Method ◽  
Jump Point ◽  
Singular Value Decomposition Method ◽  
Research Activities ◽  
Power Quality Monitoring ◽  
The Mean ◽  
Value Decomposition

Voltage sag characterization is essential for extracting information about a sag event’s origin and how sag events impact sensitive equipment. In response to such needs, more characteristics are required, such as the phase-angle jump, point-on-wave, unbalance, and sag type. However, the absence of an effective automatic segmentation method is a barrier to obtaining these characteristics. In this paper, an automatic segmentation method is proposed to improve this situation. Firstly, an extended voltage sag characterization method is described, in which segmentation plays an important role. Then, a multi-resolution singular value decomposition method is introduced to detect the boundaries of each segment. Further, the unsolved problem of how to set a threshold adaptively for different waveforms is addressed, in which the sag depth, the mean square error, and the entropy of the sag waveform are considered. Simulation data and field measurements are utilized to validate the effectiveness and reliability of the proposed method. The results show that the accuracies of both boundary detection and segmentation obtained using the proposed method are higher than those obtained using existing methods. In general, the proposed method can be implemented into a power quality monitoring system as a preprocess to support related research activities.

scholarly journals A case for variational geomagnetic data assimilation: insights from a one-dimensional, nonlinear, and sparsely observed MHD system

2007 ◽  
Vol 14 (2) ◽  
pp. 163-180 ◽  
Author(s):  
A. Fournier ◽  
C. Eymin ◽  
T. Alboussière
Keyword(s):  
Magnetic Field ◽  
Dynamical System ◽  
Velocity Field ◽  
Data Assimilation ◽  
Geomagnetic Field ◽  
Good Knowledge ◽  
One Dimensional ◽  
Secular Variations ◽  
Geomagnetic Data ◽  
The Magnetic Field

Abstract. Secular variations of the geomagnetic field have been measured with a continuously improving accuracy during the last few hundred years, culminating nowadays with satellite data. It is however well known that the dynamics of the magnetic field is linked to that of the velocity field in the core and any attempt to model secular variations will involve a coupled dynamical system for magnetic field and core velocity. Unfortunately, there is no direct observation of the velocity. Independently of the exact nature of the above-mentioned coupled system – some version being currently under construction – the question is debated in this paper whether good knowledge of the magnetic field can be translated into good knowledge of core dynamics. Furthermore, what will be the impact of the most recent and precise geomagnetic data on our knowledge of the geomagnetic field of the past and future? These questions are cast into the language of variational data assimilation, while the dynamical system considered in this paper consists in a set of two oversimplified one-dimensional equations for magnetic and velocity fields. This toy model retains important features inherited from the induction and Navier-Stokes equations: non-linear magnetic and momentum terms are present and its linear response to small disturbances contains Alfvén waves. It is concluded that variational data assimilation is indeed appropriate in principle, even though the velocity field remains hidden at all times; it allows us to recover the entire evolution of both fields from partial and irregularly distributed information on the magnetic field. This work constitutes a first step on the way toward the reassimilation of historical geomagnetic data and geomagnetic forecast.

scholarly journals History of the Munich–Maisach–Fürstenfeldbruck Geomagnetic Observatory

2015 ◽  
Vol 6 (2) ◽  
pp. 65-86 ◽  
Author(s):  
H. C. Soffel
Keyword(s):  
Geomagnetic Field ◽  
Astronomical Observatory ◽  
Final Solution ◽  
Geomagnetic Observatory ◽  
Alexander Von Humboldt ◽  
Geomagnetic Data ◽  
History Of ◽  
Nearby City ◽  
Geomagnetic Measurements

Abstract. The Munich–Maisach–Fürstenfeldbruck Geomagnetic Observatory is one of the observatories with the longest recordings of the geomagnetic field. It started with hourly measurements on 1 August 1840. The founder of the observatory in Munich was Johann von Lamont (1805–1879), the Director of the Royal Bavarian Astronomical Observatory. He had been stimulated to build his own observatory by the initiative of the Göttingen Magnetic Union founded in 1834 by Alexander von Humboldt (1769–1859) and Carl Friedrich Gauss (1777–1855). Before 1840 fewer than five observatories existed; the most prominent ones were those in London and Paris. At the beginning Lamont used equipment delivered by Gauss in Göttingen, but soon started to build instruments of his own design. Among them was a nonmagnetic theodolite which allowed precise geomagnetic measurements to be made also in the field. During the 1850s Lamont carried out geomagnetic surveys and produced geomagnetic maps for Germany and many other European countries. At the end of the nineteenth century accurate geomagnetic measurements in Munich became more and more disturbed by the magnetic stray fields from electric tramways and industry. During this period the quality of the data suffered and the measurements had to be interrupted several times. After a provisional solution in Maisach, a village 25 km west of Munich, a final solution could be found in the vicinity of the nearby city of Fürstenfeldbruck. Here the measurements started again on 1 January 1939. Since the 1980s the observatory has been part of INTERMAGNET, an organization providing almost real-time geomagnetic data of the highest quality.

scholarly journals Solar flares and variation of local geomagnetic field: Measurements by the Huancayo Observatory over 2001-2010

2017 ◽  
pp. 87-99
Author(s):  
Reyes Carlos ◽  
Ayesta Gárate ◽  
Navarro Reyes
Keyword(s):  
Solar Flare ◽  
Solar Flares ◽  
Geomagnetic Field ◽  
Activity Index ◽  
Temporal Correlation ◽  
Field Measurements ◽  
Local Variation ◽  
Geomagnetic Observatory ◽  
The Magnetic Field ◽  
National Geophysical Data Center

We study the local variation of the geomagnetic field measured by the Huancayo Geomagnetic Observatory, Peru, during 2001-2010. Initially, we sought to relate the SFI values, stored daily in the NOAA's National Geophysical Data Center, with the corresponding geomagnetic index; however, no relation was observed. Nonetheless, subsequently, a comparison between the monthly geomagnetic-activity index and the monthly SFI average allowed observing a temporal correlation between these average indices. This correlation shows that the effect of the solar flares does not simultaneously appear on the corresponding magnetic indices. To investigate this, we selected the most intense X-class flares; then, we checked the magnetic field disturbances observed in the Huancayo Geomagnetic Observatory magnetograms. We found some disturbances of the local geomagnetic field in the second and third day after the corresponding solar flare; however, the disturbance strength of the local geomagnetic field is not correlated with the X-class of the solar flare. Finally, there are some disturbances of the local geomagnetic field that are simultaneous with the X-class solar flares and they show a correlation with the total flux of the solar flare.

scholarly journals Trends in incidence rate, health care use, and costs due to rib fractures in the Netherlands

2021 ◽  
Author(s):  
Jonne T. H. Prins ◽  
Mathieu M. E. Wijffels ◽  
Sophie M. Wooldrik ◽  
Martien J. M. Panneman ◽  
Michael H. J. Verhofstad ◽  
...  
Keyword(s):  
Health Care ◽  
Incidence Rate ◽  
Health Care Costs ◽  
Indirect Costs ◽  
Rib Fractures ◽  
Work Absence ◽  
Lost Productivity ◽  
The Mean ◽  
Using Data ◽  
Care Costs

Abstract Purpose This study aimed to examine population-based trends in the incidence rate, health care consumption, and work absence with associated costs in patients with rib fractures. Methods A retrospective nationwide epidemiologic study was performed with data from patients with one or more rib fractures presented or admitted to a hospital in the Netherlands between January 1, 2015 and December 31, 2018 and have been registered in the Dutch Injury Surveillance System (DISS) or the Hospital Discharge Registry (HDR). Incidence rates were calculated using data from Statistics Netherlands. The associated direct health care costs, costs for lost productivity, and years lived with disability (YLD) were calculated using data from a questionnaire. Results In the 4-year study period, a total of 32,124 patients were registered of which 19,885 (61.9%) required hospitalization with a mean duration of 7.7 days. The incidence rate for the total cohort was 47.1 per 100,000 person years and increased with age. The mean associated direct health care costs were €6785 per patient and showed a sharp increase after the age of 75 years. The mean duration of work absence was 44.2 days with associated mean indirect costs for lost productivity of €22,886 per patient. The mean YLD was 0.35 years and decreased with age. Conclusion Rib fractures are common and associated with lengthy HLOS and work absenteeism as well as high direct and indirect costs which appear to be similar between patients with one or multiple rib fractures and mostly affected by admitted patients and age.

scholarly journals Drone-Based Remote Sensing for Research on Wind Erosion in Drylands: Possible Applications

2021 ◽  
Vol 13 (2) ◽  
pp. 283
Author(s):  
Junzhe Zhang ◽  
Wei Guo ◽  
Bo Zhou ◽  
Gregory S. Okin
Keyword(s):  
Remote Sensing ◽  
Wind Erosion ◽  
Field Measurements ◽  
Spatially Explicit ◽  
Surface Model ◽  
High Resolution Imagery ◽  
Soil Elevation ◽  
3D Photogrammetry ◽  
Using Data ◽  
Sample Set

With rapid innovations in drone, camera, and 3D photogrammetry, drone-based remote sensing can accurately and efficiently provide ultra-high resolution imagery and digital surface model (DSM) at a landscape scale. Several studies have been conducted using drone-based remote sensing to quantitatively assess the impacts of wind erosion on the vegetation communities and landforms in drylands. In this study, first, five difficulties in conducting wind erosion research through data collection from fieldwork are summarized: insufficient samples, spatial displacement with auxiliary datasets, missing volumetric information, a unidirectional view, and spatially inexplicit input. Then, five possible applications—to provide a reliable and valid sample set, to mitigate the spatial offset, to monitor soil elevation change, to evaluate the directional property of land cover, and to make spatially explicit input for ecological models—of drone-based remote sensing products are suggested. To sum up, drone-based remote sensing has become a useful method to research wind erosion in drylands, and can solve the issues caused by using data collected from fieldwork. For wind erosion research in drylands, we suggest that a drone-based remote sensing product should be used as a complement to field measurements.

scholarly journals Serum C-reactive protein metabolite (CRPM) is associated with incidence of contralateral knee osteoarthritis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anne-Christine Bay-Jensen ◽  
Asger Bihlet ◽  
Inger Byrjalsen ◽  
Jeppe Ragnar Andersen ◽  
Bente Juhl Riis ◽  
...  
Keyword(s):  
Phase Iii ◽  
Response To Treatment ◽  
C Reactive Protein ◽  
Two Phase ◽  
Knee Oa ◽  
Reactive Protein ◽  
Inflammatory Phenotype ◽  
The Mean ◽  
Using Data

AbstractThe heterogeneous nature of osteoarthritis (OA) and the need to subtype patients is widely accepted in the field. The biomarker CRPM, a metabolite of C-reactive protein (CRP), is released to the circulation during inflammation. Blood CRPM levels have shown to be associated with disease activity and response to treatment in rheumatoid arthritis (RA). We investigated the level of blood CRPM in OA compared to RA using data from two phase III knee OA and two RA studies (N = 1591). Moreover, the association between CRPM levels and radiographic progression was investigated. The mean CRPM levels were significantly lower in OA (8.5 [95% CI 8.3–8.8] ng/mL, n = 781) compared to the RA patients (12.8 [9.5–16.0] ng/mL, n = 60); however, a significant subset of OA patients (31%) had CRPM levels (≥ 9 ng/mL) comparable to RA. Furthermore, OA patients (n = 152) with CRPM levels ≥ 9 ng/mL were more likely to develop contra-lateral knee OA assessed by X-ray over a two-year follow-up period with an odds ratio of 2.2 [1.0–4.7]. These data suggest that CRPM is a blood-based biochemical marker for early identification OA patients with an inflammatory phenotype.

The Control of Foreigners as Researchers in Thailand

2009 ◽  
Vol 4 (3) ◽  
pp. 49-57 ◽  
Author(s):  
Mary J. Ditton ◽  
Leigh Lehane
Keyword(s):  
Research Performance ◽  
Field Research ◽  
Technical Expertise ◽  
Government Control ◽  
Asian Countries ◽  
Field Site ◽  
Regulatory Authorities ◽  
Research Activities ◽  
Burmese Migrants ◽  
Permit System

An important aspect of ethical conduct of field research is for the researcher to have an appropriate relationship with the legitimate gatekeepers of the field site. This paper describes our experiences of obtaining approval from regulatory authorities in Thailand for field research on Burmese migrants, and discusses the nature and rationale of such government control in Asia and Western countries. It is intended to guide future humanitarian researchers who are planning to study oppressed groups at politically sensitive research sites where regulatory authorities monitor both research sites and research performance. Thailand, like several other Southeast Asian countries, operates a permit system for foreign researchers. This permit system is designed to promote research activities in Thailand so that the results can be used to further the country's development, and to enhance the cooperation and collaboration between Thai and foreign researchers providing opportunities for the exchange of knowledge, technical expertise, and experience. This control of foreign researchers is not prohibitive; foreign humanitarian researchers can organize research and advance the welfare of targeted oppressed populations in cooperation with government agencies.

Seasonal Changes in the Water Relations of Eucalyptus behriana F. Muell. And E. microcarpa (Maiden) Maiden in the Field

1984 ◽  
Vol 32 (5) ◽  
pp. 495 ◽  
Author(s):  
BA Myers ◽  
TF Neales
Keyword(s):  
Water Potential ◽  
Water Relations ◽  
Rainfall Intensity ◽  
Field Measurements ◽  
Canopy Conductance ◽  
Laboratory Studies ◽  
Short Term ◽  
The Mean ◽  
Type Response ◽  
Vapour Pressure Difference

Field observations of some parameters of the water relations of the two eucalypt species E. behriana and E. microcarpa in dry sclerophyll, mallee and woodland vegetation were made at three sites from 1980 to 1983. The mean ( n = 519) water potential measured at dawn (Ψdawn) was -3.07± 0.01 MPa and fluctuated seasonally with rainfall intensity over the range -2.0 ± 0, 1 to -4.4 ± 0.1 MPa ( n = 30). Both species behaved similarly and some osmotic adjustment took place. Mean leaf conductance (gs) varied between 0.151 ± 0.006 and 0.003 ± 0.001 mol m-2 s-1 . Maximum daily values of gs were linearly related to Ψdawn as it fluctuated seasonally. The slope of this linear regression was not significantly different from that relating these values of gs and Ψ, when both were measured concurrently. There were thus no indications of a distinction between the responses of gs to long- and short-term fluctuations of Ψ or of a threshold-type response of gs to Ψ. Field measurements indicated that gs was decreased at high values of vapour pressure difference (Δe). In laboratory studies with seedlings of the two species gs decreased from 0.5 to 0.1 mol m-2 s-I as Δe increased from 0.5 to 3.0 kPa. Leaf and canopy conductance were the predominant plant determinants of transpiration rate (Er) in this type of vegetation which has the capacity to restrict Et via the effect of water potential (Ψ) on gs and also by the response of gs to Δe. Some of the water relations parameters of E. behriana indicated that this species was better able to withstand drought than was E microcarpa.

POSTPARTUM AMENORRHOEA IN RURAL EASTERN UTTAR PRADESH, INDIA

1998 ◽  
Vol 30 (2) ◽  
pp. 227-243
Author(s):  
K. N. S. YADAVA ◽  
S. K. JAIN
Keyword(s):  
Higher Education ◽  
Uttar Pradesh ◽  
Current Status Data ◽  
North India ◽  
Current Status ◽  
Data Sets ◽  
Survival Status ◽  
The Mean ◽  
The Difference ◽  
Using Data

This paper calculates the mean duration of the postpartum amenorrhoea (PPA) and examines its demographic, and socioeconomic correlates in rural north India, using data collected through 'retrospective' (last but one child) as well as 'current status' (last child) reporting of the duration of PPA.The mean duration of PPA was higher in the current status than in the retrospective data;n the difference being statistically significant. However, for the same mothers who gave PPA information in both the data sets, the difference in mean duration of PPA was not statistically significant. The correlates were identical in both the data sets. The current status data were more complete in terms of the coverage, and perhaps less distorted by reporting errors caused by recall lapse.A positive relationship of the mean duration of PPA was found with longer breast-feeding, higher parity and age of mother at the birth of the child, and the survival status of the child. An inverse relationship was found with higher education of a woman, higher education of her husband and higher socioeconomic status of her household, these variables possibly acting as proxies for women's better nutritional status.

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