scholarly journals Are stress responses to geomagnetic storms mediated by the cryptochrome compass system?

2012 ◽  
Vol 279 (1736) ◽  
pp. 2081-2090 ◽  
Author(s):  
James Close
Keyword(s):  
Stress Responses ◽  
Geomagnetic Field ◽  
Conceptual Models ◽  
Scientific Literature ◽  
Geomagnetic Storms ◽  
Molecular System ◽  
Circadian Pacemaker ◽  
Dispersal Strategy ◽  
Established Role ◽  
Compass System

A controversial body of literature demonstrates associations of geomagnetic storms (GMS) with numerous cardiovascular, psychiatric and behavioural outcomes. Various melatonin hypotheses of GMS have suggested that temporal variation in the geomagnetic field (GMF) may be acting as an additional zeitgeber (a temporal synchronizer) for circadian rhythms, with GMS somehow interfering with the hypothesized system. The cryptochrome genes are known primarily as key components of the circadian pacemaker, ultimately involved in controlling the expression of the hormone melatonin. Cryptochrome is identified as a clear candidate for mediating the effect of GMS on humans, demonstrating the prior existence of several crucial pieces of evidence. A distinct scientific literature demonstrates the widespread use of geomagnetic information for navigation across a range of taxa. One mechanism of magnetoreception is thought to involve a light-dependent retinal molecular system mediated by cryptochrome, acting in a distinct functionality to its established role as a circadian oscillator. There is evidence suggesting that such a magnetosense—or at least the vestiges of it—may exist in humans. This paper argues that cryptochrome is not acting as secondary geomagnetic zeitgeber to influence melatonin synthesis. Instead, it is hypothesized that the cryptochrome compass system is mediating stress responses more broadly across the hypothalamic–pituitary–adrenal (HPA) axis (including alterations to circadian behaviour) in response to changes in the GMF. Two conceptual models are outlined for the existence of such responses—the first as a generalized migrational/dispersal strategy, the second as a stress response to unexpected signals to the magnetosense. It is therefore proposed that GMS lead to disorientation of hormonal systems in animals and humans, thus explaining the effects of GMS on human health and behaviour.

scholarly journals Fruit-eating fishes of Banara arguta (Salicaceae) in the Miranda River floodplain, Pantanal wetland

2011 ◽  
Vol 11 (4) ◽  
pp. 373-376 ◽  
Author(s):  
Raul Costa-Pereira ◽  
Francisco Severo-Neto ◽  
Tamires Soares Yule ◽  
Ana Paula Tinti Pereira
Keyword(s):  
Seed Dispersal ◽  
Fish Assemblage ◽  
Scientific Literature ◽  
Ecological Studies ◽  
Dispersal Strategy ◽  
Ecological Consequences ◽  
River Floodplain ◽  
Seed Dispersers ◽  
Pantanal Wetland

The role of fish as frugivorous and its ecological consequences are often neglected in ecological studies. However, the importance of the interaction between fish and plants is gaining force in scientific literature, and fish has been considered effective seed dispersers. The fruit-eating fish assemblage of Banara arguta (Salicaceae) was evaluated in Southern Pantanal wetlands. Nine species were reported consuming fruits, with different strategies to capture them. The distribution of B. arguta associated with the Pantanal floodplain and the presence of several species of fruit-eating fish, suggest that ichthyochory can be an important seed dispersal strategy to B. arguta.

scholarly journals Vulnerability Concepts and its Application in Various Fields: A Review on Geographical Perspective

2014 ◽  
Vol 8 ◽  
pp. 63-81 ◽  
Author(s):  
Shitangsu Kumar Paul
Keyword(s):  
Conceptual Models ◽  
Sustainability Science ◽  
Scientific Literature ◽  
Sustainable Livelihoods ◽  
Holistic Approach ◽  
Lessons Learned ◽  
Multidisciplinary Research ◽  
Research Cooperation ◽  
Research Traditions ◽  
Universal Definition

Vulnerability has no universal definition. Experts from various disciplines use the concept and define vulnerability, which leads diverse measuring methods to serve their own purpose and interests. Approaches to define vulnerability vary among the disciplines because of the various components of risk, household response and welfare outcomes. The objective of this paper is to present an overview based on available scientific literature from various disciplines to examine the origin, evolution and use of the vulnerability concept across different field of studies. Vulnerability is exclusively used in various disciplines such as geography, anthropology, economics, ecology, public health, poverty and development, sustainable livelihoods, famine and food security, sustainability science, land management, disaster management and climate change. Therefore, different disciplines have their own reasons for defining, measuring and developing conceptual models of vulnerability; hence there is no reason to presume that concepts, measures and methods will be universal across the disciplines. Lessons learned from one area may not be equally suitable for all. Hence, differences between various fields need to be bridged by a holistic approach and multidisciplinary research cooperation, and geography as a unique multidisciplinary field of study has the major disciplinary legitimacy to fill up the gaps and to create a common platform to work together in vulnerability research among the various research traditions. DOI: http://dx.doi.org/10.3329/jles.v8i0.20150 J. Life Earth Sci., Vol. 8: 63-81, 2013

scholarly journals From solar eruption to transformer saturation: the space weather chain

2013 ◽  
Vol 8 (S300) ◽  
pp. 500-501
Author(s):  
Larisa Trichtchenko
Keyword(s):  
Space Weather ◽  
Geomagnetic Field ◽  
Geomagnetic Storms ◽  
Interplanetary Medium ◽  
Practical Importance ◽  
Power Grids ◽  
Geomagnetically Induced Currents ◽  
Large Space ◽  
Weather Events ◽  
Induced Currents

AbstractCoronal mass ejections (CME) and associated interplanetary-propagated solar wind disturbances are the established causes of the geomagnetic storms which, in turn, create the most hazardous impacts on power grids. These impacts are due to the large geomagnetically induced currents (GIC) associated with variations of geomagnetic field during storms, which, flowing through the transformer windings, cause extra magnetisation. That can lead to transformer saturation and, in extreme cases, can result in power blackouts. Thus, it is of practical importance to study the solar causes of the large space weather events. This paper presents the example of the space weather chain for the event of 5-6 November 2001 and a table providing complete overview of the largest solar events during solar cycle 23 with their subsequent effects on interplanetary medium and on the ground. This compact overview can be used as guidance for investigations of the solar causes and their predictions, which has a practical importance in everyday life.

Magnetometer-based autonomous orbit determination via a measurement differencing extended Kalman filter during geomagnetic storms

2020 ◽  
Vol 92 (3) ◽  
pp. 428-439
Author(s):  
Feng Cui ◽  
Dong Gao ◽  
Jianhua Zheng
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Orbit Determination ◽  
Geomagnetic Field ◽  
Field Model ◽  
Geomagnetic Storms ◽  
Content Type ◽  
Geomagnetic Field Model ◽  
Autonomous Orbit Determination ◽  
Time Accuracy

Purpose The main reason for the low accuracy of magnetometer-based autonomous orbit determination is the coarse accuracy of the geomagnetic field model. Furthermore, the geomagnetic field model error increases obviously during geomagnetic storms, which can still further reduce the navigation accuracy. The purpose of this paper is to improve the accuracy of magnetometer-based autonomous orbit determination during geomagnetic storms. Design/methodology/approach In this paper, magnetometer-based autonomous orbit determination via a measurement differencing extended Kalman filter (MDEKF) is studied. The MDEKF algorithm can effectively remove the time-correlated portion of the measurement error and thus can evidently improve the accuracy of magnetometer-based autonomous orbit determination during geomagnetic storms. Real flight data from Swarm A are used to evaluate the performance of the MDEKF algorithm presented in this study. A performance comparison between the MDEKF algorithm and an extended Kalman filter (EKF) algorithm is investigated for different geomagnetic storms and sampling intervals. Findings The simulation results show that the MDEKF algorithm is superior to the EKF algorithm in terms of estimation accuracy and stability with a short sampling interval during geomagnetic storms. In addition, as the size of the geomagnetic storm increases, the advantages of the MDEKF algorithm over the EKF algorithm become more obvious. Originality/value The algorithm in this paper can improve the real-time accuracy of magnetometer-based autonomous orbit determination during geomagnetic storms with a low computational burden and is very suitable for low-orbit micro- and nano-satellites.

scholarly journals The Geomagnetic Field (GMF) Modulates Nutrient Status and Lipid Metabolism during Arabidopsis thaliana Plant Development

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1729
Author(s):  
Monirul Islam ◽  
Gianpiero Vigani ◽  
Massimo E. Maffei
Keyword(s):  
Magnetic Field ◽  
Arabidopsis Thaliana ◽  
Lipid Metabolism ◽  
Plant Development ◽  
Stress Responses ◽  
Geomagnetic Field ◽  
Time Course ◽  
Seed Set ◽  
Developmental Stages ◽  
Lipid Transfer Protein

The Geomagnetic field (GMF) is a typical component of our planet. Plant perception of the GMF implies that any magnetic field (MF) variation would induce possible metabolic changes. In this work was we assessed the role of the GMF on Arabidopsis thaliana Col0 mineral nutrition and lipid metabolism during plant development. We reduced the local GMF (about 40 μT) to Near Null Magnetic Field (NNMF, about 30 nT) to evaluate the effects of GMF on Arabidopsis in a time-course (from rosette to seed-set) experiment by studying the lipid content (fatty acids, FA; and surface alkanes, SA) and mineral nutrients. The expression of selected genes involved in lipid metabolism was assessed by Real-Time PCR (qPCR). A progressive increase of SA with carbon numbers between 21 and 28 was found in plants exposed to NNMF from bolting to flowering developmental stages, whereas the content of some FA significantly (p < 0.05) increased in rosette, bolting and seed-set developmental stages. Variations in SA composition were correlated to the differential expression of several Arabidopsis 3-ketoacyl-CoAsynthase (KCS) genes, including KCS1, KCS5, KCS6, KCS8, and KCS12, a lipid transfer protein (LTPG1) and a lipase (LIP1). Ionomic analysis showed a significant variation in some micronutrients (Fe, Co, Mn and Ni) and macronutrients (Mg, K and Ca) during plant development of plants exposed to NNMF. The results of this work show that A. thaliana responds to variations of the GMF which are perceived as is typical of abiotic stress responses.

scholarly journals A statistical analysis of the relationship between Pc4 and Pc5 ULF waves, solar winds and geomagnetic storms for predicting earthquake precursor signatures in low latitude regions

2021 ◽  
Vol 880 (1) ◽  
pp. 012010
Author(s):  
S N A Syed Zafar ◽  
Roslan Umar ◽  
N H Sabri ◽  
M H Jusoh ◽  
A Yoshikawa ◽  
...  
Keyword(s):  
Solar Wind ◽  
Geomagnetic Field ◽  
Geomagnetic Storms ◽  
Earthquake Precursor ◽  
Ulf Waves ◽  
Low Latitude ◽  
Geomagnetic Indices ◽  
Solar Winds ◽  
Solar Wind Parameters ◽  
The Relationship

Abstract Short-term earthquake forecasting is impossible due to the seismometer’s limited sensitivity in detecting the generation of micro-fractures prior to an earthquake. Therefore, there is a strong desire for a non-seismological approach, and one of the most established methods is geomagnetic disturbance observation. Previous research shows that disturbances in the ground geomagnetic field serves as a potential precursor for earthquake studies. It was discovered that electromagnetic waves (EM) in the Ultra-Low Frequency (ULF) range are a promising tool for studying the seismomagnetic effect of earthquake precursors. This study used a multiple regression approach to analyse the preliminary study on the relationship between Pc4 (6.7-22 mHz) and Pc5 (1.7-6.7 mHz) ULF magnetic pulsations, solar wind parameters and geomagnetic indices for predicting earthquake precursor signatures in low latitude regions. The ground geomagnetic field was collected from Davao station (7.00° N, 125.40° E), in the Philippines, which experiences nearby earthquake events (Magnitude <5.0, depth <100 km and epicentre distance from magnetometer station <100 km). The Pc5 ULF waves show the highest variance with four solar wind parameters, namely SWS, SWP, IMF-Bz, SIE and geomagnetic indices (SYM/H) prior to an earthquake event based on the regression model value of R2 = 0.1510. Furthermore, the IMF-Bz, SWS, SWP, SWE, and SYM/H were found to be significantly correlated with Pc5 ULF geomagnetic pulsation. This Pc5 ULF magnetic pulsation behaviour in solar winds and geomagnetic storms establishes the possibility of using Pc5 to predict earthquakes.

scholarly journals Propuesta de indicadores de recursos de competitividad turística en los espacios naturales protegidos

2015 ◽  
Vol 13 (4) ◽  
pp. 947-957
Author(s):  
Lidia Blanco Cerradelo ◽  
◽  
Mª Isabel Diéguez Castrillón ◽  
Ana Gueimonde Canto ◽  
◽  
...  
Keyword(s):  
Conceptual Models ◽  
Scientific Literature ◽  
Natural Areas ◽  
Tourist Destination ◽  
Wide Range ◽  
Destination Competitiveness ◽  
Protected Natural Areas

The models for the analysis of tourist destination competitiveness present in theory various factors that directly or indirectly affect competitiveness. The most prominent among these factors are a wide range of elements that can be integrated into the resource construct. In addition, the scientific literature on destination competitiveness establishes that the characteristics of the destination justify the consideration of one or several types of resources as well as their prevalence and importance. The objective of this paper is to identify which must be the type of resources and resource indicators to consider in a competitiveness model applicable to a tourist destination with its own particular characteristics such as the protected natural areas (PNA). To do this, we will review the different conceptual models of destination competitiveness in order to analyze, synthesize and evaluate the diversity of resources and indicators referred to in those models

scholarly journals ANALISIS RESPON MEDAN GEOMAGNET ANTARA STASIUN DI EKUATOR MAGNET DAN STASIUN BIAK SAAT BADAI GEOMAGNET PADA MERIDIAN MAGNET 210⁰ MM

2016 ◽  
Vol 13 (2) ◽  
pp. 63
Author(s):  
Anwar Santoso
Keyword(s):  
Response Time ◽  
Geomagnetic Storm ◽  
Geomagnetic Field ◽  
Field Data ◽  
Geomagnetic Storms ◽  
Geomagnetic Disturbance ◽  
Magnetic Equator ◽  
High Latitudes ◽  
Geomagnetic Equator ◽  
Occurrence Probability

Geomagnetic storm is a geomagnetic disturbance that occurs globally. Until now believed that the greatest impact of geomagnetic storms occurred in the high latitudes and decreases with decreasing latitude to the equator. However, based on the data component of the geomagnetic field H obtained CPMN other phenomena, that is H minimum of Onagawa station (31,15o LU; 212,63o BT magnetic coordinates) is smaller than the H minimum at Biak station (9,73o latitude; 207,39o BT magnetic coordinates) during geomagnetic storms on July 15, 2000. This reality is different from what was believed to be on top. To ensure this, then done the analysis of the geomagnetic field H component response based on the latitude using the geomagnetic field data from Biak station and stations around 210o MM for the whole event a strong geomagnetic storms (Dst <-100 nT) during 1995-2001. Results of the analysis showed that the response time of geomagnetic field geomagnetic storm in Biak is greater than at the magnetic equator (YAP) with an difference average of H is 59,27 nT. EEJ and CEJ pattern in the EEJ region (10o S to 10o N magnetic coordinate) shown could effected to the response of geomagnetic geomagnetic. The most important to note that if the geomagnetic response in Indonesia higher than in the geomagnetic equator (YAP) then the occurrence probability of GIC in Indonesia is higher.  AbstrakBadai geomagnet merupakan gangguan geomagnet yang terjadi secara global. Sampai saat ini dipercaya bahwa dampak terbesar badai geomagnet terjadi di lintang tinggi dan semakin menurun dengan menurunnya lintang sampai di ekuator. Namun, berdasarkan olah data komponen H medan geomagnet dari CPMN diperoleh fenomena lain yaitu H minimum dari stasiun Onagawa (31,15⁰ LU; 212,63⁰ BT koordinat magnet) lebih kecil dari H minimum Balai Penjejakan dan Kendali Wahana Antariksa (BPKWA) Biak (9,73⁰ LS; 207,39⁰ BT koordinat magnet) saat badai geomagnet 15 Juli 2000. Kenyataan ini berbeda dari apa yang telah dipercayai di atas. Untuk memastikan hal ini maka dilakukan analisis respon komponen H medan geomagnet berdasarkan lintang menggunakan data komponen H medan geomagnet dari BPKWA Biak dan stasiun di sekitar 210⁰ MM untuk seluruh kejadian badai geomagnet kuat (Dst < -100 nT) selama 1995-2001. Hasil analisis diperoleh bahwa respon medan geomagnet saat badai geomagnet di Biak lebih besar dari pada di ekuator magnet (YAP) dengan rata-rata selisih ∆H-nya 59,27 nT. EEJ dan CEJ di daerah EEJ (10⁰ LU sampai 10⁰ LS magnet) terbukti mempengaruhi respon geomagnet. Hal terpenting yang perlu diperhatikan dari hasil ini adalah bahwa jika respon geomagnet di Indonesia lebih tinggi dibandingkan di daerah ekuator geomagnet (YAP) maka potensi kemunculan GIC juga lebih besar terjadi di Indonesia. 

Study on Variation Rate Characters of Mid-to-Low Latitude Area Geomagnetic Field during Geomagnetic Storms

2013 ◽  
Vol 448-453 ◽  
pp. 2125-2131
Author(s):  
Xiao Mao Wang
Keyword(s):  
Geomagnetic Field ◽  
Geomagnetic Storms ◽  
Power Grid ◽  
Geomagnetic Latitude ◽  
Induced Current ◽  
Low Latitude ◽  
Geomagnetically Induced Current ◽  
Faraday’S Law ◽  
Variation Rate ◽  
Measurement And Control

Geomagnetic field changes acutely during geomagnetic storms. According to Faraday's law of electromagnetic induction, the change of the geomagnetic field produces geomagnetically induced current (GIC) in power grid, which directly damages the power equipment and threatens safe operation of power grid. The more dramatically geomagnetic field changes, the bigger geomagnetically induced current in power grid becomes, and thus, the greater harm it brings to power grid. In this paper, based on the H and D components of recent geomagnetic storm data measured by several mid-to-low latitude geomagnetic observatories, the variation law of the amplitude of north-south and east-west geomagnetic component change rate (dX/dt and dY/dt) pulse with geomagnetic latitude was analyzed when geomagnetic field changed very severely. Finally, the possibilities of power grid in different direction affected by GIC with the change of latitude were discussed. The analysis results will contribute to the evaluation, measurement and control of GIC in Chinese current and future power grid.

The Plasmasphere During Major Geomagnetic Storms: Analysis Of Trapped Particles In The Outer Radiation Belt

2020 ◽  
Author(s):  
Jessy Matar ◽  
Benoit Hubert ◽  
Stan Cowley ◽  
Steve Milan ◽  
Zhonghua Yao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Geomagnetic Field ◽  
Radiation Belt ◽  
Ring Current ◽  
Geomagnetic Storms ◽  
Outer Radiation Belt ◽  
Trapped Particles ◽  
The Earth ◽  
Field Lines

&lt;p&gt; The coupling between the Earth&amp;#8217;s magnetic field and the interplanetary magnetic field (IMF) transported by the solar wind results in a cycle of magnetic field lines opening and closing generally known as the Dungey substorm cycle, mostly governed by the process of magnetic reconnection. The geomagnetic field lines can therefore have either a closed or an open topology, i.e. lower latitude field lines are closed (map from southern ionosphere to the northern), while higher latitude field lines are open (map from one polar ionosphere into interplanetary space). Closed field lines can trap electrically charged particles that bounce between mirror points located in the North and South hemispheres while drifting in longitude around the Earth, forming the plasmasphere, the radiation belts and the ring current. The outer boundary of the plasmasphere is the plasmapause. Its location is mostly driven by the interplay of the corotation electric field of ionospheric origin, and the convection electric field that results from the interaction between the IMF and the geomagnetic field. At times of prolonged intense coupling between these fields, the response of the magnetosphere becomes global and a geomagnetic storm develops. The ring current created by the motion of the trapped energetic particles intensifies and then decays as the storm abates. This study aims to find a possible relationship between the evolution of the trapped population and the process of magnetic reconnection during storm times. The EUV instrument on board the NASA-IMAGE spacecraft observed the distribution of the trapped helium ions (He+) in the plasmasphere. We consider several cases of intense geomagnetic storms observed by the IMAGE satellite. We identify the plasmapause location (Lpp) during those cases. We find a strong correlation between the Dst index and Lpp. The ring current and the trapped particles are expected to vary during storms. We use the Tsyganenko magnetic field model to map the electric potential between the Heppner-Maynard boundary (HMB) in the ionosphere and the magnetosphere and estimate the voltage and electric field in the vicinity of the plasmapause. The ionospheric electric field is deduced from the ionospheric convection velocity measured by the SuperDARN (SD) radar network at high latitudes. The tangential electric field component of the moving plasmapause boundary is estimated from IMAGE-EUV observations of the plasmasphere and is compared with expectations based on the SD data. We combine measurements of the trapped population from IMAGE-EUV and IMAGE-FUV observations of the aurora to better understand and quantify the variability of the Earth's outer radiation belt during strong storms. The auroral precipitation at ionospheric latitude is studied using FUV imaging and compared to the He+ response during the storms.&lt;/p&gt;

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