Study on Role of 234Th in Uranium Series Nuclides Migration

1990 ◽  
Vol 212 ◽  
Author(s):  
Toshihiko Ohnuki ◽  
Shoji Watanabe ◽  
Takashi Murakami
Keyword(s):  
Field Data ◽  
Migration Velocity ◽  
Migration Behavior ◽  
Relative Mobility ◽  
Fixation Rate ◽  
Ore Deposit ◽  
Uranium Series ◽  
Daughter Nuclide ◽  
Different Depths

ABSTRACTThe role of 234Th, a daughter nuclide of 238U having a half life of 24 days, in the migration of uranium series nuclides has been studied to understand the mechanism which gives a higher migration velocity of 238U than that of 234U. We assume that 234Th is adsorbed at two different sites; one, where 234Th is reversibly adsorbed, and the other, where 234Th is irreversibly fixed. Calculations have shown that the fixation of ^Th to a rock can cause the apparent migration velocity of 234U to be reduced compared to that of 238U and this agrees with observed field data. Changes in the fixation rate constants affect the relative mobility of 238U and 234U, and this can account for the different migration behavior at different depths in the Koongarra ore deposit.

scholarly journals The Determinants of Access to Sanitation: The Role of Human Rights and the Challenges of Measurement

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1676
Author(s):  
Rebecca Schiel ◽  
Bruce M. Wilson ◽  
Malcolm Langford
Keyword(s):  
Sustainable Development ◽  
Human Rights ◽  
Field Data ◽  
Data Availability ◽  
Regression Analyses ◽  
Human Right ◽  
Sustainable Development Goal ◽  
Development Goal ◽  
The Sustainable Development

Ten years after the United Nation’s recognition of the human right to water and sanitation (HRtWS), little is understood about how these right impacts access to sanitation. There is limited identification of the mechanisms responsible for improvements in sanitation, including the international and constitutional recognition of rights to sanitation and water. We examine a core reason for the lack of progress in this field: data quality. Examining data availability and quality on measures of access to sanitation, we arrive at three findings: (1) where data are widely available, measures are not in line with the Sustainable Development Goal (SDG) targets, revealing little about changes in sanitation access; (2) data concerning safe sanitation are missing in more country-year observations than not; and (3) data are missing in the largest proportions from the poorest states and those most in need of progress on sanitation. Nonetheless, we present two regression analyses to determine what effect rights recognition has on improvements in sanitation access. First, the available data are too limited to analyze progress toward meeting SDGs related to sanitation globally, and especially in regions most urgently needing improvements. Second, utilizing more widely available data, we find that rights seem to have little impact on access.

scholarly journals THE ROLE OF SOCIAL MEDIA ON MIGRATION DECISION-MAKING PROCESSES: Case of Indonesian Student in University of Groningen

2018 ◽  
Vol 6 (1) ◽  
pp. 515
Author(s):  
Inayah Hidayati
Keyword(s):  
Decision Making ◽  
Social Media ◽  
Migration Decision ◽  
Decision Making Process ◽  
Migration Behavior ◽  
Interview Guide ◽  
Destination Area ◽  
Decision Making Processes ◽  
The Impact

Objective: This research aims to explain the impact of social media on the migration decision-making process of Indonesian student migrants in University of Groningen who used a social media account. In detail, this research will consider the role of social media in the migration decision-making process of students who emigrated from Indonesia and how they uses social media in the context of the migration decision-making process. Methods: The data collected included qualitative data from in-depth interviews and supported by study literatures. An interview guide was formulated to facilitate the indepth interviews and generate a better understanding of migration behavior. Expectation: Social media help Indonesian student migrants on migration decision making process and they use social media for searching information about destination area. Result: Student migrant in University of Groningen use their social media to gain information before they choose that university for study. They use Facebook to making contact with their friends and collagues in the destination country. Student group on Facebook help Indonesian student to get information about school and daily life.

scholarly journals Perturbation of Combined Saccade-Vergence Movements by Microstimulation in Monkey Superior Colliculus

1999 ◽  
Vol 81 (5) ◽  
pp. 2279-2296 ◽  
Author(s):  
Vivek Chaturvedi ◽  
Jan A. M. van Gisbergen
Keyword(s):  
Superior Colliculus ◽  
Local Population ◽  
Three Dimensional ◽  
Weighted Averaging ◽  
Target Onset ◽  
Saccade Onset ◽  
Different Depths

Perturbation of combined saccade-vergence movements by microstimulation in monkey superior colliculus. This study investigated the role of the monkey superior colliculus (SC) in the control of visually (V)-guided combined saccade-vergence movements by assessing the perturbing effects of microstimulation. We elicited an electrical saccade (E) by stimulation (in 20% of trials) in the SC while the monkey was preparing a V-guided movement to a near target. The target was aligned such that E- and V-induced saccades had similar amplitudes but different directions and such that V-induced saccades had a significant vergence component (saccades to a near target). The onset of the E-stimulus was varied from immediately after V-target onset to after V-saccade onset. E-control trials, where stimulation was applied during fixation of a V-target, yielded the expected saccade but no vergence. By contrast, early perturbation trials, where the E-stimulus was applied soon after the onset of the V-target, caused an E-triggered response with a clear vergence component toward the V-target. Midflight perturbation, timed to occur just after the monkey initiated the movement toward the target, markedly curtailed the ongoing vergence component during the saccade. Examination of pooled responses from both types of perturbation trials showed weighted-averaging effects between E- and V-stimuli in both saccade and fast vergence components. Both components exhibited a progression from E- to V-dominance as the E-stimulus was delayed further. This study shows that artificial intervention in the SC, while a three-dimensional (3D) refixation is being prepared or is ongoing, can affect the timing (when) and the metric specification (where) of both saccades and vergence. To explain this we interpret the absence of overt vergence in the E-controls as being caused by a zero-vergence change command rather than reflecting the mere absence of a collicular vergence signal. In the perturbation trials, the E-evoked zero-vergence signal competes with the V-initiated saccade-vergence signal, thereby giving rise to a compromised 3D response. This effect would be expected if the population of movement cells at each SC site is tuned in 3D, combining the well-known topographical code for direction and amplitude with a nontopographical depth representation. On E-stimulation, the local population would yield a net saccade signal caused by the topography, but the cells coding for different depths would be excited equally, causing the vergence change to be zero.

Solar flare forecasting model using 3D magnetic field data

2020 ◽  
Author(s):  
Xin Huang
Keyword(s):  
Magnetic Field ◽  
Deep Learning ◽  
Solar Flare ◽  
Solar Flares ◽  
Field Data ◽  
Active Regions ◽  
Forecasting Model ◽  
Magnetic Field Data ◽  
The Magnetic Field

<p>Solar flares originate from the release of the energy stored in the magnetic field of solar active regions. Generally, the photospheric magnetograms of active regions are used as the input of the solar flare forecasting model. However, solar flares are considered to occur in the low corona. Therefore, the role of 3D magnetic field of active regions in the solar flare forecast should be explored. We extrapolate the 3D magnetic field using the potential model for all the active regions during 2010 to 2017, and then the deep learning method is applied to extract the precursors of solar flares in the 3D magnetic field data. We find that the 3D magnetic field of active regions is helpful to build a deep learning based forecasting model.</p>

Effects of burial of seeds and seedlings from different seed sizes on the emergence and growth of Strophostyles helvola

1996 ◽  
Vol 74 (8) ◽  
pp. 1322-1330 ◽  
Author(s):  
Mary Yanful ◽  
M. A. Maun
Keyword(s):  
Lake Erie ◽  
Sandy Beach ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Large Mass ◽  
Burial Depth ◽  
Different Depths ◽  
Mass Burial ◽  
Provincial Park

Field and greenhouse studies were conducted to examine the role of seed mass in (i) the emergence of seedlings of Strophostyles helvola (L.) Ell. from different depths of burial in sand and (ii) the ability of seedlings originating from seeds of different seed mass (weight per seed) to re-emerge from sand deposits. Seeds were sorted into four different seed mass classes (small, < 55 mg; medium, 55–65 mg; large, 65–75 mg; and extra large, > 75 mg) and sown at different depths ranging from 2 to 24 cm in sand on a sandy beach at Port Burwell Provincial Park along Lake Erie. Seeds of large mass class (65–75 mg) sown at 18 cm depth produced the largest plants. Under greenhouse conditions, all S. helvola seedlings buried to 100 and 125% of their height survived the treatment, but survival declined to 66% when they were buried to 150% of their height. Stimulation in growth was observed only when the seedlings were buried to 50 and 75% of their height. Seedlings originating from large seed masses took fewer days to re-emerge from different burial depths than seedlings from small seeds. However, the interaction term between seed mass and burial depth for the re-emergence of seedlings was not significant. Keywords: seed mass, burial of seeds, burial of seedlings, Strophostyles helvola, seedling emergence.

scholarly journals DISCOVERY AND STUDY HISTORY POKROVSKY GOLD ORE DEPOSIT IN THE AMUR REGION

2020 ◽  
pp. 63-72
Author(s):  
ANTON VLADIMIROVICH MELNIKOV ◽  
◽  
VITALY ALEKSEEVICH STEPANOV ◽  
DMITRIY VALERYEVICH YUSUPOV ◽  
◽  
...  
Keyword(s):  
Native Gold ◽  
Amur Region ◽  
Near Surface ◽  
Ore Deposit ◽  
Gold Ore ◽  
Gold Silver ◽  
History Of ◽  
Typical Composition ◽  
Gold Ore Deposit

A brief history of the discovery and study of the large Pokrovsky gold ore deposit of the Amur Region, from the ores of which about 63 tons of gold were extracted, is given. The role of scientific and production organizations and individual geologists in the discovery of the deposit is shown. According to the results of almost half a century of research, the deposit is classified as a near-surface gold-silver formation with a typical composition of ores, near-ore metasomatites and native gold for deposits of this type. The closest analogue of Pokrovka is the Kubak deposit of the Omolonsky gold-silver province.

scholarly journals Market Competition and the Effectiveness of Performance Pay

2020 ◽  
Author(s):  
Pooyan Khashabi ◽  
Matthias Heinz ◽  
Nick Zubanov ◽  
Tobias Kretschmer ◽  
Guido Friebel
Keyword(s):  
Field Data ◽  
Pay For Performance ◽  
Market Competition ◽  
Performance Pay ◽  
Curvilinear Relationship ◽  
Specific Factors ◽  
Strong Competition ◽  
External Forces ◽  
Moderating Role

It is well established that the effectiveness of pay-for-performance (PfP) schemes depends on employee- and organization-specific factors. However, less is known about the moderating role of external forces such as market competition. Our theory posits that competition generates two counteracting effects—the residual market and competitor response effects—that vary with competition and jointly generate a curvilinear relationship between PfP effectiveness and competition. Weak competition discourages effort response to PfP because there is little residual market to gain from rivals, whereas strong competition weakens incentives because an offsetting response from competitors becomes more likely. PfP hence has the strongest effect under moderate competition. Field data from a bakery chain and its competitive environment confirm our theory and let us refute several alternative interpretations.

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