Anomalies of LF signal during seismic activity in November?December 2004

International audienceA signal transmitted by Japan Time Standard LF station (40 kHz, Fukushima prefecture) and recorded in Petropavlovsk-Kamchatski (Russia) is analyzed during a time interval from 1 July 2004 till 24 January 2005. This interval is characterized by quiet seismic conditions up to the beginning of November, but rather strong seismic activity occurs in November and December not far from Hokkaido (Japan) and in the region of northern Kuril Islands. There were three series of earthquakes with M=5.6?7.1 in a zone of sensitivity of our wave path during two months. Nighttime "bay-like" phase and amplitude anomalies of the LF signal are observed several days before and during every series of earthquakes. During the whole period of seismic activity a significant shift in terminator times is also evident. The spectrum of LF seismo-induced anomalies shows a clear increase for the period of about 25 min

Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia

This study investigated Holocene tree-line history and climatic change in the pre-Polar Urals, northeast European Russia. A sediment core from Mezhgornoe Lake situated at the present-day alpine tree-line was studied for pollen, plant macrofossils, Cladocera and diatoms. A peat section from Vangyr Mire in the nearby mixed mountain taiga zone was analysed for pollen. The results suggest that the study area experienced a climatic optimum in the early Holocene and that summer temperatures were at least 2°C warmer than today. Tree birch immigrated to the Mezhgornoe Lake area at the onset of the Holocene. Mixed spruce forests followed at ca. 9500-9000 14C yr BP. Climate was moist and the water level of Mezhgornoe Lake rose rapidly. The hypsithermal phase lasted until ca. 5500-4500 14C yr BP, after which the mixed forest withdrew from the Mezhgornoe catchment as a result of the climate cooling. The gradual altitudinal downward shift of vegetation zones resulted in the present situation, with larch forming the tree-line

Effectiveness of legislative changes obligating notification of prolonged sickness absence and assessment of remaining work ability on return to work and work participation : a natural experiment in Finland

Objectives Policies have been introduced to reduce sickness absence, but their effectiveness is largely unknown. In a natural experiment, we examined effects of legislative changes on return to work and work participation. Methods The source population consisted of up to 72164 Finnish public sector employees with a permanent job contract in 2008-2011 (before) and in 2013-2014 (after). We used employees with a continuous sickness absence of at least 30 calendar-days (n=5708-6393), 60 compensated days (n=1481-1655) and 90 compensated days (n=766-932). We examined sustainable return to work (a minimum of 28 consecutive working days) with survival analysis as well as monthly work participation after a sickness absence, and annual gain in work participation after the intervention, using trajectory analyses. Results Sustainable return to work after 60days of sickness absence occurred earlier after the legislative changes (p value 0.017), although the effect reduced towards the end of the follow-up. There were no differences in return to work after a 30 or 90days of sickness absence. The largest annual gain, postintervention versus preintervention, in monthly work participation was observed among employees with 60days of sickness absence and was 230.9 person-years/10000 employees. The corresponding annual gains among those with 30days and 90days of sickness absence were 51.8 and 39.6, respectively. Conclusions Our findings suggest that the legislative changes, obligating early notification of prolonged sickness absences as well as assessment of remaining work ability and possibilities to continue working, may enhance sustainable return to work in the short term. Other measures will be needed to enhance work participation, especially in the long term.Peer reviewe

Preseismic ULF effectand possible interpretation

We present the results of ULF magnetic field observation at Karimshino station (Kamchatka, Russia). Using a case study we discovered an effect of suppression of ULF intensity about 2-6 days before rather strong and isolated seismic shocks (magnitude M = 4.6-6.6). It is revealed for nighttime and the horizontal component of ULF field (G) in the frequency range 0.01-0.1 Hz. Then we prove the reliability of the effect by computed correlation between G (or 1/G) and especially calculated seismic indexes Ks for the rather long period of observation from June 2000 to November 2001. Our recent data confirm the validity of the effect. We show here a similar result during a period of frequent strong seismic activity in April-May 2002. It is highly probable that the effect observed is connected with the increase in plasma density perturbations inside the ionosphere, which are induced by preseismic water and gas release at the ground surface and following energy transportation into the ionosphere by atmospheric gravity waves. Two models are discussed and computed: the first is a decrease of penetration coefficient of Alfven waves from the magnetosphere due to a turbulent increase in effective Pedersen conductivity in the ionosphere, and the second is a change in wave number (k) distribution of source ionospheric turbulence. One of the mechanisms or both could be responsible for the observed 2-3 times suppression of ULF magnetic field noise at the ground

Mild template synthesis of a copper(II)-containing macrocyclic compound with 4,4,6-trimethyl-2,3,7,8-tetraazanonen-6-dithiohydrazide-1,9 in a gelatin-immbolized matrix

The complexing processes in the triple copper(II)-thiocarbohydrazide-propanone system taking place in a copper(II) hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous-alkaline solutions (pH∼12), containing thiocarbohydrazide and propanone, have been studied. Template synthesis leading to a macrocyclic coordination compound with the tetradentate N,N,S,S-donor ligand, (4,4,6-trimethyl-2,3,7,8-tetraazanonen-6-dithiohydrazide-1,9), occurs under these specific conditions when thiocarbohydrazide and propanone are the ligand synthons

Template synthesis in the M(II)-thiocarbohydrazide-diacetyl triple system (M = Ni, Cu) in a metal(II)hexacyanoferrate(II) gelatin-immobilized matrix

Novel complexing processes in the CuII-thiocarbohydrazide- diacetyl triple system proceeding to a copper(II)hexacyanoferrate gelatin-immobilized matrix system in contact with aqueous-alkaline (pH 12) solutions containing thiocarbohydrazide and diacetyl, have been studied. It has been shown that mild template synthesis of copper(II) coordination compounds with (N,S,N,S)- and (N,N,N,N)- tetradentate ligands - 4,5-dimethyl-2,3,6,7- tetraazaoctadien-3,5-dithiohydrazide-1,8 and 3,10-dithio - 6,7,13,14- tetramethyl-1,2,4,5,8,9,11,12-octaazacyclotetradecatetraene-1,5,7,12 take place, respectively. At the same time, the complexing process in the system under examination, when it occurs in aqueous-ethanol solution between CuCl2 and the organic compounds indicated, leads to copper(II) coordination compounds with another (N,S,N,S)-tetradentate ligand - 3,9,10,16-tetramethyl-6,13 - dimercapto-2,17-dioxo-4,5,7,8,11,12,14,15-tetraazaoctadecahexaene - 3,6,8,10,12,15. In both cases, thiocarbohydrazide and diacetyl are ligand synthons in these complexing processes

Complexing reactions in the Ni(II)-5-methyl-4-amino-3-thiooxo-1,2,4-triazapentene-1-methanal and Ni(II)-5-methyl-4-amino-3-thiooxo-1,2,4-triazapentene-1-propanone triple systems

Complexing processes in the NiII-TTA-methanal (A) and NiII-TTA-propanone (B) triple systems (TTA - 5-methyl-4-amino-3-thiooxo-1, 2, 4-triazapentene-1) in ethanol solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix have been studied. In the NiII-TTA-methanal system, formation of NiII oligomeric coordination compounds in which metal chelate cycles are connected by -H2C-O-CH2- structural groups, takes place. In the NiII-TTA-propanone triple system, formation of only NiII complexes with TTA takes place. No complexing process in the triple systems in nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix was found. © 2009 Taylor & Francis

The effect of the August 21, 2017 total solar eclipse on the phase of VLF/LF signals

An experimental study of the phase and amplitude observations of sub‐ionospheric very low and low frequency signals is performed to analyse the response of the lower ionosphere during the August 21, 2017 total solar eclipse in the United States of America. Three different sub‐ionospheric wave paths are investigated. The length of the paths varies from 2200 to 6400 km and the signal frequencies are 21.4 kHz, 25.2 kHz and 40.75 kHz. The two paths cross the region of the total eclipse and the third path is in the region of 40‐60% of obscuration. None of the signals reveal any noticeable amplitude changes during the eclipse while negative phase anomalies (from ‐33° to ‐95°) are detected for all three paths. It is shown that the effective reflection height of the ionosphere in low and middle latitudes is increased by about 3‐5 km during the eclipse. Estimation of the electron density change in the lower ionosphere caused by the eclipse, using linear recombination law, shows that the average decrease is by 2.1 to 4.5 times

Template synthesis in the M(II)-thiocarbohydrazide-diacetyl triple system (M = Ni, Cu) in a metal(II)hexacyanoferrate(II) gelatin-immobilized matrix

Novel complexing processes in the CuII-thiocarbohydrazide- diacetyl triple system proceeding to a copper(II)hexacyanoferrate gelatin-immobilized matrix system in contact with aqueous-alkaline (pH 12) solutions containing thiocarbohydrazide and diacetyl, have been studied. It has been shown that mild template synthesis of copper(II) coordination compounds with (N,S,N,S)- and (N,N,N,N)- tetradentate ligands - 4,5-dimethyl-2,3,6,7- tetraazaoctadien-3,5-dithiohydrazide-1,8 and 3,10-dithio - 6,7,13,14- tetramethyl-1,2,4,5,8,9,11,12-octaazacyclotetradecatetraene-1,5,7,12 take place, respectively. At the same time, the complexing process in the system under examination, when it occurs in aqueous-ethanol solution between CuCl2 and the organic compounds indicated, leads to copper(II) coordination compounds with another (N,S,N,S)-tetradentate ligand - 3,9,10,16-tetramethyl-6,13 - dimercapto-2,17-dioxo-4,5,7,8,11,12,14,15-tetraazaoctadecahexaene - 3,6,8,10,12,15. In both cases, thiocarbohydrazide and diacetyl are ligand synthons in these complexing processes

Soft template synthesis of macrocyclic copper(II) chelates with 3,9-dithio-4,8-diaza-6-oxaundekandithioamide-1,11 in a Cu 2[Fe(CN)6]-gelatin-immobilized matrix

Soft template synthesis of macricyclic copper(II) chelates with 3,9-dithio-4,8-diaza-6-oxaundekandithioamide-1,11 in a Cu 2[Fe(CN)6]-gelatin-immobilized matrix (GIM), was presented. The process of template synthesis between copper(II), dithiomalonamide and methanol occurred only in GIM. Results indicated that the complexing process in the system under examination was independent of the gelatin type