Long-Term Observations of Schumann Resonances at Portishead (UK)

Constructive interference of lightning-generated signals in the extremely low frequency (ELF) below 100 Hz is the source of a global electromagnetic phenomenon in the Earth’s atmosphere known as Schumann Resonances (SR). SR are excited at frequencies of 7.8, 14, 20, 26, … Hz, and their diurnal and seasonal intensity variations are largely dependent on changes in the location and magnitude of the major lightning centres in Southeast Asia, Africa, and South America. In the last five decades, extensive research has focused on reconstructing the spatial and temporal evolution in global lighting activity using SR measurements, and more recently on analysing the links to climate change, transient luminous events (TLE), and biological systems. In this study, a quasi-electrostatic antenna, primarily designed as a thunderstorm warning system, is for the first time applied to measure background variability in the SR band at an urban site in Southwest England. Data collected continuously from June 2015 for a 5-year period are suitably filtered and analysed showing that SR is the dominant contribution to the fair-weather displacement current measured by the sensor in the band 10–45 Hz. Diurnal and seasonal signal amplitude variations have been found to be consistent with previous studies and show the African-European lightning centre to prevail due to the shorter source-observer distance. Also, it is shown that long-term global changes in the ocean and land temperature, and the subsequent effect on the major lightning hotspots, may be responsible for the inter-annual variability of SR intensity, indicating that the largest increase occurred during the 2015–2016 super El-Niño episode.

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Calcium threshold shift enables frequency-independent control of plasticity by an instructive signal

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1613897113 ◽

2016 ◽

Vol 113 (46) ◽

pp. 13221-13226 ◽

Cited By ~ 17

Author(s):

Claire Piochon ◽

Heather K. Titley ◽

Dana H. Simmons ◽

Giorgio Grasselli ◽

Ype Elgersma ◽

...

Keyword(s):

Stimulus Frequency ◽

Low Frequency ◽

Signal Amplitude ◽

Long Term Potentiation ◽

Wide Frequency Range ◽

Calcium Transients ◽

Threshold Shift ◽

Calcium Signal ◽

Frequency Independent

At glutamatergic synapses, both long-term potentiation (LTP) and long-term depression (LTD) can be induced at the same synaptic activation frequency. Instructive signals determine whether LTP or LTD is induced, by modulating local calcium transients. Synapses maintain the ability to potentiate or depress over a wide frequency range, but it remains unknown how calcium-controlled plasticity operates when frequency variations alone cause differences in calcium amplitudes. We addressed this problem at cerebellar parallel fiber-Purkinje cell synapses, which can undergo LTD or LTP in response to 1-Hz and 100-Hz stimulation. We observed that high-frequency activation elicits larger spine calcium transients than low-frequency stimulation under all stimulus conditions, but, regardless of activation frequency, climbing fiber (CF) coactivation provides an instructive signal that further enhances calcium transients and promotes LTD. At both frequencies, buffering calcium prevents LTD induction and LTP results instead, identifying the enhanced calcium signal amplitude as the critical parameter contributed by the instructive CF signal. These observations show that it is not absolute calcium amplitudes that determine whether LTD or LTP is evoked but, instead, the LTD threshold slides, thus preserving the requirement for relatively larger calcium transients for LTD than for LTP induction at any given stimulus frequency. Cerebellar LTD depends on the activation of calcium/calmodulin-dependent kinase II (CaMKII). Using genetically modified (TT305/6VA and T305D) mice, we identified α-CaMKII inhibition upon autophosphorylation at Thr305/306 as a molecular event underlying the threshold shift. This mechanism enables frequency-independent plasticity control by the instructive CF signal based on relative, not absolute, calcium thresholds.

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Long Term Effects of Low Frequency (10 Hz) Vagus Nerve Stimulation on EEG and Heart Rate Variability in Crohn's Disease: A Case Report

Brain Stimulation ◽

10.1016/j.brs.2014.08.001 ◽

2014 ◽

Vol 7 (6) ◽

pp. 914-916 ◽

Cited By ~ 26

Author(s):

Didier Clarençon ◽

Sonia Pellissier ◽

Valérie Sinniger ◽

Astrid Kibleur ◽

Dominique Hoffman ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Crohn’S Disease ◽

Case Report ◽

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Low Frequency ◽

Long Term Effects

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Edible Energy Production and Energy Return on Investment—Long-Term Analysis of Global Changes

Energies ◽

10.3390/en14041011 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1011

Author(s):

Bartłomiej Bajan ◽

Joanna Łukasiewicz ◽

Agnieszka Poczta-Wajda ◽

Walenty Poczta

Keyword(s):

Energy Efficiency ◽

Return On Investment ◽

Food Production ◽

Energy Production ◽

Crop Production ◽

Fossil Fuels ◽

Animal Production ◽

Global Changes ◽

Energy Return On Investment

The projected increase in the world’s population requires an increase in the production of edible energy that would meet the associated increased demand for food. However, food production is strongly dependent on the use of energy, mainly from fossil fuels, the extraction of which requires increasing input due to the depletion of the most easily accessible deposits. According to numerous estimations, the world’s energy production will be dependent on fossil fuels at least to 2050. Therefore, it is vital to increase the energy efficiency of production, including food production. One method to measure energy efficiency is the energy return on investment (EROI), which is the ratio of the amount of energy produced to the amount of energy consumed in the production process. The literature lacks comparable EROI calculations concerning global food production and the existing studies only include crop production. The aim of this study was to calculate the EROI of edible crop and animal production in the long term worldwide and to indicate the relationships resulting from its changes. The research takes into account edible crop and animal production in agriculture and the direct consumption of fossil fuels and electricity. The analysis showed that although the most underdeveloped regions have the highest EROI, the production of edible energy there is usually insufficient to meet the food needs of the population. On the other hand, the lowest EROI was observed in highly developed regions, where production ensures food self-sufficiency. However, the changes that have taken place in Europe since the 1990s indicate an opportunity to simultaneously reduce the direct use of energy in agriculture and increase the production of edible energy, thus improving the EROI.

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The global iron industry and the Anthropocene

The Anthropocene Review ◽

10.1177/2053019620982332 ◽

2020 ◽

pp. 205301962098233

Author(s):

Kevin Mallinger ◽

Martin Mergili

Keyword(s):

Iron Ore ◽

Magnetic Particles ◽

Steel Corrosion ◽

Global Changes ◽

Iron Industry ◽

Iron And Steel ◽

Physical Chemical ◽

Organic Particles ◽

Rock Overburden

Iron ore is the most mined metal and the second most mined mineral in the world. The mining of iron ore and the processing of iron and steel increased sharply during the 20th century and peaked at the beginning of the 21st century. Associated processes along the iron ore cycle (mining, processing, recycling, weathering) such as the massive displacement of rock, the emission of waste and pollutants, or the weathering of products resulted in long-term environmental and stratigraphic changes. Key findings link the iron ore industry to 170 gigatons of rock overburden, a global share of CO2 with 7.6%, mercury with 7.4%, and a variety of other metals, pollutants, and residues. These global changes led to physical, chemical, biological, magnetic, and sequential markers, which are used for the justification of the Anthropocene. The potential markers vary significantly regarding their persistence and measurability, but key findings are summarised as TMPs (Technogenic Magnetic Particles), SCPs (Spheroidal Carbonaceous fly ash Particles), POPs (Persistent Organic Particles), heavy metals (vanadium, mercury, etc.), as well as steel input and steel corrosion residues.

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Induction of long-term potentiation without participation of N-methyl-D-aspartate receptors in kitten visual cortex

Journal of Neurophysiology ◽

10.1152/jn.1991.65.1.20 ◽

1991 ◽

Vol 65 (1) ◽

pp. 20-32 ◽

Cited By ~ 47

Author(s):

Y. Komatsu ◽

S. Nakajima ◽

K. Toyama

Keyword(s):

Nmda Receptors ◽

Stimulus Frequency ◽

Low Frequency ◽

Nmda Antagonist ◽

Long Term Potentiation ◽

Conditioning Stimulation ◽

Postsynaptic Potential ◽

Term Potentiation ◽

Stimulation Of

1. Intracellular recording was made from layer II-III cells in slice preparations of kitten (30-40 days old) visual cortex. Low-frequency (0.1 Hz) stimulation of white matter (WM) usually evoked an excitatory postsynaptic potential (EPSP) followed by an inhibitory postsynaptic potential (IPSP). The postsynaptic potentials (PSPs) showed strong dependence on stimulus frequency. Early component of EPSP and IPSP evoked by weak stimulation both decreased monotonically at frequencies greater than 0.5-1 Hz. Strong stimulation similarly depressed the early EPSP at higher frequencies (greater than 2 Hz) and replaced the IPSP with a late EPSP, which had a maximum amplitude in the stimulus frequency range of 2-5 Hz. 2. Very weak WM stimulation sometimes evoked EPSPs in isolation from IPSPs. The falling phase of the EPSP revealed voltage dependence characteristic to the responses mediated by N-methyl-D-aspartate (NMDA) receptors and was depressed by application of an NMDA antagonist DL-2-amino-5-phosphonovalerate (APV), whereas the rising phase of the EPSP was insensitive to APV. 3. The early EPSPs followed by IPSPs were insensitive to APV but were replaced with a slow depolarizing potential by application of a non-NMDA antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX), indicating that the early EPSP is mediated by non-NMDA receptors. The slow depolarization was mediated by NMDA receptors because it was depressed by membrane hyperpolarization or addition of APV. 4. The late EPSP evoked by higher-frequency stimulation was abolished by APV, indicating that it is mediated by NMDA receptors, which are located either on the recorded cell or on presynaptic cells to the recorded cells. 5. Long-term potentiation (LTP) of EPSPs was examined in cells perfused with solutions containing 1 microM bicuculline methiodide (BIM), a gamma-aminobutyric acid (GABA) antagonist. WM was stimulated at 2 Hz for 15 min as a conditioning stimulus to induce LTP, and the resultant changes were tested by low-frequency (0.1 Hz) stimulation of WM. 6. LTP of early EPSPs occurred in more than one-half of the cells (8/13) after strong conditioning stimulation. The rising slope of the EPSP was increased 1.6 times on average. 7. To test involvement of NMDA receptors in the induction of LTP in the early EPSP, the effect of conditioning stimulation was studied in a solution containing 100 microM APV, which was sufficient to block completely synaptic transmission mediated by NMDA receptors. LTP occurred in the same frequency and magnitude as in control solution.

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A Chronology of El Niño Events from Primary Documentary Sources in Northern Peru*

Journal of Climate ◽

10.1175/2007jcli1830.1 ◽

2008 ◽

Vol 21 (9) ◽

pp. 1948-1962 ◽

Cited By ~ 53

Author(s):

R. Garcia-Herrera ◽

D. Barriopedro ◽

E. Hernández ◽

H. F. Diaz ◽

R. R. Garcia ◽

...

Keyword(s):

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Low Frequency ◽

Primary Sources ◽

Proxy Data ◽

Documentary Sources ◽

Low Frequency Variability ◽

Northern Peru

Abstract The authors present a chronology of El Niño (EN) events based on documentary records from northern Peru. The chronology, which covers the period 1550–1900, is constructed mainly from primary sources from the city of Trujillo (Peru), the Archivo General de Indias in Seville (Spain), and the Archivo General de la Nación in Lima (Peru), supplemented by a reassessment of documentary evidence included in previously published literature. The archive in Trujillo has never been systematically evaluated for information related to the occurrence of El Niño–Southern Oscillation (ENSO). Abundant rainfall and river discharge correlate well with EN events in the area around Trujillo, which is very dry during most other years. Thus, rain and flooding descriptors, together with reports of failure of the local fishery, are the main indicators of EN occurrence that the authors have searched for in the documents. A total of 59 EN years are identified in this work. This chronology is compared with the two main previous documentary EN chronologies and with ENSO indicators derived from proxy data other than documentary sources. Overall, the seventeenth century appears to be the least active EN period, while the 1620s, 1720s, 1810s, and 1870s are the most active decades. The results herein reveal long-term fluctuations in warm ENSO activity that compare reasonably well with low-frequency variability deduced from other proxy data.

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A Review of Crack Detection In-Line Inspection Case Studies

2010 8th International Pipeline Conference, Volume 1 ◽

10.1115/ipc2010-31114 ◽

2010 ◽

Cited By ~ 2

Author(s):

Neil Bates ◽

David Lee ◽

Clifford Maier

Keyword(s):

Crack Growth ◽

Case Studies ◽

Crack Detection ◽

Growth Parameters ◽

Probability Distributions ◽

Low Frequency ◽

Probability Of Failure ◽

Probability Of Detection ◽

Inspection Data

This paper describes case studies involving crack detection in-line inspections and fitness for service assessments that were performed based on the inspection data. The assessments were used to evaluate the immediate integrity of the pipeline based on the reported features and the long-term integrity of the pipeline based on excavation data and probabilistic SCC and fatigue crack growth simulations. Two different case studies are analyzed, which illustrate how the data from an ultrasonic crack tool inspection was used to assess threats such as low frequency electrical resistance weld seam defects and stress corrosion cracking. Specific issues, such as probability of detection/identification and the length/depth accuracy of the tool, were evaluated to determine the suitability of the tool to accurately classify and size different types of defects. The long term assessment is based on the Monte Carlo method [1], where the material properties, pipeline details, crack growth parameters, and feature dimensions are randomly selected from certain specified probability distributions to determine the probability of failure versus time for the pipeline segment. The distributions of unreported crack-related features from the excavation program are used to distribute unreported features along the pipeline. Simulated crack growth by fatigue, SCC, or a combination of the two is performed until failure by either leak or rupture is predicted. The probability of failure calculation is performed through a number of crack growth simulations for each of the reported and unreported features and tallying their respective remaining lives. The results of the probabilistic analysis were used to determine the most effective and economical means of remediation by identifying areas or crack mechanisms that contribute most to the probability of failure.

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