The new gravity system—changes in international gravity base values and anomaly values

Geophysics ◽  
1979 ◽  
Vol 44 (8) ◽  
pp. 1352-1366 ◽  
Author(s):  
George P. Woollard
Keyword(s):  
Sea Level ◽  
Global Scale ◽  
Absolute Gravity ◽  
Geodetic Reference System ◽  
Limiting Factor ◽  
Worldwide Distribution ◽  
The Difference ◽  
Correction Terms ◽  
Discernible Difference ◽  
Gravity System

An assessment is made of (1) the reliability of the changes in the absolute gravity datum and standard incorporated in the IGSN 71 values of Morelli et al (1974), and (2) the effect of these changes and those incorporated in the new international gravity formula (Geodetic Reference System 1967) defining theoretical gravity values at sea level on gravity anomaly values. Pendulum‐interval comparisons with modern absolute gravity intervals between Washington, D.C.; Teddington, England; Paris, France; and Potsdam, East Germany indicate that the correction of 14 mgal to the Potsdam datum is correct to within .03 ± .016 mgal. Although there appear to be occasional discrepancies in the IGSN 71 values of the order of 0.1 mgal, in general their reliability appears to approximate ±0.05 mgal. A discrepancy of approximately −0.03 mgal per 1000 mgal of absolute gravity is indicated, however, in the gravity standard defined by the IGSN 71 values over the range of modern absolute gravity determinations between Fairbanks, Alaska and Bogotá, Colombia. An evaluation of the earlier attempt to standardize gravity on a global scale (Woollard and Rose, 1963) indicates a mean datum difference of 14.7 mgal (standard deviation 0.2 mgal) relative to IGSN 71 values at 776 sites having a worldwide distribution. No discernible difference in gravity standard from that of the IGSN 71 values is indicated except in South America, where the Woollard and Rose values are found to incorporate a difference in standard of O.2 mgal per 1000 mgal. It is shown that anomaly conversions from the old to the new gravity system can be effected directly using the old anomaly values. Two correction terms are required, specifically, (1) a constant representing the difference in base value used relative to the IGSN 71 value for the base, and (2) a latitude‐dependent term representing the difference in theoretical sea level gravity using the old International Gravity Formula (IGF) and the new GRS 67 formula. Test conversions of anomaly values on the old gravity system for regional areas involving data from several sources indicate that, in general, anomaly conversion to the new gravity system can be obtained with a reliability of about 0.3 to 0.5 mgal. The limiting factor is the unknown variation in gravimeter calibration standards represented.

Changes of Ionic and Oxygen Isotopic Composition of the Snowpack at the Glacier Austre Okstindbreen, Norway, 1995

1998 ◽  
Vol 29 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Peter Raben ◽  
Wilfred H. Theakstone
Keyword(s):  
Isotopic Composition ◽  
Sea Level ◽  
Oxygen Isotopes ◽  
Oxygen Isotopic Composition ◽  
Isotopic Ratios ◽  
Vertical Variations ◽  
Oxygen Isotopic ◽  
The Difference ◽  
Liquid Precipitation ◽  
Different Altitudes

Marked vertical variations of ions and oxygen isotopes were present in the snowpack at the glacier Austre Okstindbreen during the pre-melting phase in 1995 at sites between 825 m and 1,470 m above sea level. As the first meltwater percolated from the top of the pack, ions were moved to a greater depth, but the isotopic composition remained relatively unchanged. Ions continued to move downwards through the pack during the melting phase, even when there was little surface melting and no addition of liquid precipitation. The at-a-depth correlation between ionic concentrations and isotopic ratios, strong in the pre-melting phase, weakened during melting. In August, concentrations of Na+ and Mg2+ ions in the residual pack were low and vertical variations were slight; 18O enrichment had occurred. The difference of the time at which melting of the snowpack starts at different altitudes influences the input of ions and isotopes to the underlying glacier.

scholarly journals 881. Efficacy of Antibiotic Prophylaxis with Vancomycin in Cardiothoracic Surgery

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S477-S477
Author(s):  
Margaret Cooper ◽  
Jing Zhao
Keyword(s):  
Primary Outcome ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Medical Center ◽  
Surgical Site Infections ◽  
National Healthcare ◽  
National Healthcare Safety Network ◽  
High Incidence ◽  
The Difference ◽  
Gram Negative Organisms ◽  
Discernible Difference

Abstract Background Due to the high incidence of methicillin-resistant Staphylococcus aureus (MRSA) at the Detroit Medical Center, vancomycin is now routinely part of the prophylaxis regimen for cardiothoracic (CT) surgery. The study aims to compare the rate and types of surgical site infections (SSIs) when vancomycin is added to cefazolin for CT surgery compared to cefazolin alone. Methods This was a retrospective cohort study conducted at two university-affiliated hospitals. Patients who underwent CT surgery between January 2008 and August 2017 and had a readmission for SSI within 90 days of procedure were included. Patients who received cefazolin were compared to patients who received both cefazolin and vancomycin for CT surgery prophylaxis. The primary outcome was incidence of SSIs within 90 days of surgery as defined by the Centers for Disease Control and National Healthcare Safety Network. Results Out of 828 patients who underwent CT surgeries, there were 32 patients readmitted within 90 days for SSI. SSI occurred in 4.7% of patients who received cefazolin monotherapy, and 2.4% of patients who received both cefazolin and vancomycin (p=0.095). There was no discernible difference in types of SSI between groups. Pathogens were isolated in 78% of SSIs, with 75% Gram-positive and 19% Gram-negative organisms. SSIs resulted in an average 9.8 days in the hospital and 28.9 days of antibiotic therapy, and led to a total of 15 additional procedures. Conclusion Vancomycin added to cefazolin for prophylaxis in CT surgery resulted in lower incidence of SSI, however the difference was not statistically significant. Disclosures All Authors: No reported disclosures

Urban heat island estimation from improved selection of urban and rural stations by DTW algorithm

2021 ◽  
Author(s):  
Yonghong Hu ◽  
Gensuo Jia ◽  
Jinlong Ai ◽  
Yong Zhang ◽  
Meiting Hou ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Urban Climate ◽  
Global Scale ◽  
Heat Island ◽  
Climate Effect ◽  
Urban Heat ◽  
The Difference ◽  
Temperature Records ◽  
Dynamic Time ◽  
Selection Of

Abstract Typical urban and rural temperature records are essential for the estimation and comparison of urban heat island effects in different regions, and the key issues are how to identify the typical urban and rural stations. This study tried to analyze the similarity of air temperature sequences by using dynamic time warping algorithm (DTW) to improve the selection of typical stations. We examined the similarity of temperature sequences of 20 stations in Beijing and validated by remote sensing, and the results indicated that DTW algorithm could identify the difference of temperature sequence, and clearly divide them into different groups according to their probability distribution information. The analysis for station pairs with high similarity could provide appropriate classification for typical urban stations (FT, SY, HD, TZ, CY, CP, MTG, BJ, SJS, DX, FS) and typical rural stations (ZT, SDZ, XYL) in Beijing. We also found that some traditional rural stations can’t represent temperature variation in rural surface because of their surrounding environments highly modified by urbanization process in last decades, and they may underestimate the urban climate effect by 1.24℃. DTW algorithm is simple in analysis and application for temperature sequences, and has good potentials in improving urban heat island estimation in regional or global scale by selecting more appropriate temperature records.

GlacierMIP3 global glacier mass change equilibration experiments - rationale and experimental design

2021 ◽  
Author(s):  
Harry Zekollari ◽  
Regine Hock ◽  
Ben Marzeion ◽  
Fabien Maussion ◽  
Lilian Schuster ◽  
...  
Keyword(s):  
Experimental Design ◽  
Sea Level ◽  
Ice Sheets ◽  
Global Scale ◽  
Mass Change ◽  
Glacier Mass Balance ◽  
Model Intercomparison ◽  
Climate Conditions ◽  
Equilibrium Volume ◽  
Global Mean

<p>Glaciers outside the ice sheets are major contributors to today’s sea-level rise and are projected to remain so in the coming century. With the goal to better assess the future sea-level contribution from glaciers and to quantify related uncertainties, the Glacier Model Intercomparison Project (GlacierMIP) has set out to develop a series of coordinated experiments to be run as a community-wide effort.</p><p>The first two phases of the GlacierMIP have focused on the evolution of glaciers throughout the 21<sup>st</sup> century (Hock et al., 2019; Marzeion et al., 2020). In the third phase of GlacierMIP (GlacierMIP3 – equilibration), a new set of experiments has been designed to investigate the equilibration of glaciers under constant climate conditions. These experiments will allow us to answer the following fundamental questions:</p><p>1. What would be the equilibrium volume and area of all glaciers outside the ice sheets if global mean temperatures were to stabilize at present-day levels?</p><p>2. What would be the equilibrium volume and area of all glaciers outside the ice sheets if global mean temperatures were to stabilize at different temperature levels (e.g. +1.5, +2, relative to pre-industrial)?</p><p>3. For each of these global mean temperature stabilization scenarios, how much time would the glaciers need to reach their new equilibrium?</p><p>In this contribution, we present the experimental design of GlacierMIP3 and open up the floor for ideas and discussions about possible processing of these experiments. We also invite interested individuals and groups to join us to discuss the possibility of their model to be included in the newest phase of GlacierMIP.</p><p> </p><p><strong>References</strong></p><p><strong>GlacierMIP1</strong>: Hock, R., Bliss, A., Marzeion, B., Giesen, R.H., Hirabayashi, Y., Huss, M., Radic, V., Slangen, A.B.A. (2019), GlacierMIP – A model intercomparison of global-scale glacier mass-balance models and projections, Journal of Glaciology 65(251), 453-467, doi: 10.1017/jog.2019.22</p><p><strong>GlacierMIP2</strong>: Marzeion, B., Hock, R., Anderson, B., Bliss, A., Champollion, N., Fujita, K., Huss, M., Immerzeel, W., Kraaijenbrink, P., Malles, J-H., Maussion, F., Radic, V., Rounce, D.R., Sakai, A., Shannon, S., van de Wal, R., Zekollari, H. (2020), Partitioning the Uncertainty of Ensemble Projections of Global Glacier Mass Change, Earth’s Future 8(7), e2019EF001470, doi: 10.1029/2019EF001470</p>

scholarly journals Comparative Study of Comfort Indicators for School Constructions in Sustainability Methodologies: Schools in the Amazon and the Southeast Region of Brazil

2019 ◽  
Vol 11 (19) ◽  
pp. 5216 ◽  
Author(s):  
Tatiana Santos Saraiva ◽  
Edson Martins da Silva ◽  
Manuela Almeida ◽  
Luís Bragança
Keyword(s):  
Social Issues ◽  
Global Scale ◽  
Northern Region ◽  
Sustainable Construction ◽  
School Buildings ◽  
Environmental Preservation ◽  
Southeast Region ◽  
Acoustic Comfort ◽  
The Difference ◽  
Entire Planet

In the 1970s and 1980s, the effects of pollution in the atmosphere grew from a local to a global scale, affecting the entire planet. Consequently, economic and social issues began to be increasingly more connected with environmental protection. Several measures were taken towards environmental preservation, many of those related to the sustainable construction of buildings. This work intended to make a parallel between comfort indicators among different schools in Brazil, beginning with the specific analyses of schools in Juiz de Fora (Minas Gerais, MG), in the Southeast region, and in Macapá (Amapa, AP), in the Amazon or Northern region. This comparison between schools is made to demonstrate the need to adapt methodologies and certifications that promote sustainability in school buildings for each region of Brazil. Questionnaires about ergonomic, thermal, visual and acoustic comfort, and air quality, were applied in two high-school buildings in Juiz de Fora, Academia School and Santa Catarina School, and in two high schools in Macapá, Tiradentes School and Professor Gabriel Almeida Café school, to understand the difference between these two regions of Brazil regarding comfort conditions. A comparison between the results of the four schools was made, proving the necessity of the elaboration of a specific methodology for each Brazilian region.

scholarly journals Microbial feedbacks optimize ocean iron availability

2020 ◽  
Vol 117 (9) ◽  
pp. 4842-4849
Author(s):  
Jonathan Maitland Lauderdale ◽  
Rogier Braakman ◽  
Gaël Forget ◽  
Stephanie Dutkiewicz ◽  
Michael J. Follows
Keyword(s):  
Large Fraction ◽  
Global Scale ◽  
Microbial Production ◽  
Limiting Factor ◽  
Iron Cycling ◽  
Dissolved Iron ◽  
Surface Ocean ◽  
Source Sink ◽  
Model Ocean ◽  
Additional Iron

Iron is the limiting factor for biological production over a large fraction of the surface ocean because free iron is rapidly scavenged or precipitated under aerobic conditions. Standing stocks of dissolved iron are maintained by association with organic molecules (ligands) produced by biological processes. We hypothesize a positive feedback between iron cycling, microbial activity, and ligand abundance: External iron input fuels microbial production, creating organic ligands that support more iron in seawater, leading to further macronutrient consumption until other microbial requirements such as macronutrients or light become limiting, and additional iron no longer increases productivity. This feedback emerges in numerical simulations of the coupled marine cycles of macronutrients and iron that resolve the dynamic microbial production and loss of iron-chelating ligands. The model solutions resemble modern nutrient distributions only over a finite range of prescribed ligand source/sink ratios where the model ocean is driven to global-scale colimitation by micronutrients and macronutrients and global production is maximized. We hypothesize that a global-scale selection for microbial ligand cycling may have occurred to maintain “just enough” iron in the ocean.

On the Chemical Reactivity of the Phytochrome Chromophore in the Pr and Pfr Form

1985 ◽  
Vol 40 (3-4) ◽  
pp. 215-218 ◽  
Author(s):  
Fritz Thümmler ◽  
Peter Eilfeld ◽  
Wolfhart Rüdiger ◽  
Doo-Khil Moon ◽  
Pill-Soon Song
Keyword(s):  
Reaction Kinetics ◽  
Rate Constants ◽  
Chemical Reactivity ◽  
Order Reaction ◽  
First Order Reaction ◽  
Limiting Factor ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
The Difference

The reactivity of the phytochrome chromophore and related tetrapyrroles towards ozone and tetranitromethane was investigated. Both oxidizing reagents cause bleaching of the main absorp­tion band of the pigment. The rate constants for this bleaching were determined under conditions of pseudo first order reaction kinetics. The rate constants for the reaction with ozone are similar for native phytochrome and for freely accessible tetrapyrroles (biliverdin, small chromopeptides from phytochrome) indicating that accessibility is not the limiting factor for the reaction with ozone. Under a variety of conditions, the Pfr chromophore reacts by about 10% faster than the Pr chromophore. This may reflect the true difference in reactivity. The rate constants for the reaction with tetranitromethane are much larger for biliverdin, bilirubin and small chromopeptides from phytochrome than for native phytochrome. The limiting factor for this reaction in native phytochrome therefore is the accessibility of the chromophore by the reagent. Previous conclusions on the difference in exposure of the tetrapyrrole chromophore in Pr and Pfr are confirmed.

Nutrient concentration in sediments accumulated in pre-treatment basins of urban LID technologies

2019 ◽  
Vol 79 (5) ◽  
pp. 1000-1006 ◽  
Author(s):  
F. K. F. Geronimo ◽  
M. C. Maniquiz-Redillas ◽  
J. S. Hong ◽  
L. H. Kim
Keyword(s):  
Low Impact Development ◽  
Limiting Factor ◽  
Particle Sizes ◽  
Storm Events ◽  
Nutrient Reduction ◽  
Sediment Retention ◽  
The Difference ◽  
Pre Treatment ◽  
Sand And Gravel

Abstract In this study, the contribution of pre-treatment basins of low impact development (LID) technologies to nutrient reduction performance was evaluated by understanding the distribution of nutrient in sediments accumulated in each system. The captured sediments were mostly silt to medium sand ranging from 9% to 92% of the sediments collected. Greater average N and P concentrations were found in silt particles amounting to 345 mg/kg and 696 mg/kg, respectively compared to sand and gravel. Although, N concentrations in accumulated sediments were found to be highly variable at different particle sizes (CV: 0.24 to 0.77) compared to P concentration (CV: 0.08 to 0.36) attributed to effective P treatment mechanism through deposition compared to complex nitrogen removal mechanisms. In addition, the difference between N and P concentrations of sediments collected in the pre-treatment basins of LID technologies and in-situ soil was attributed to the continuous pollutant input to the LID technologies during storm events. The study proved that pre-treatment basins of stormwater LID technologies reinforced the nutrient removal performances through sediment retention. The findings of this research may be used to design pre-treatment basins of LID technologies considering nutrients as a limiting factor.

scholarly journals Intestinal absorption of different types of folate in healthy subjects with an ileostomy

2002 ◽  
Vol 88 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Erik J. M. Konings ◽  
Freddy J. Troost ◽  
Jacqueline J. M. Castenmiller ◽  
Harry H. S. Roomans ◽  
Piet A. van den Brandt ◽  
...  
Keyword(s):  
Folic Acid ◽  
Folate Intake ◽  
Limiting Factor ◽  
Short Term ◽  
Relative Absorption ◽  
Different Types ◽  
The Difference ◽  
Folate Bioavailability ◽  
Serum Response ◽  
Food Folate

Our knowledge on the absorption of folate is incomplete. The deconjugation process as a possible limiting factor in the absorption of folates was investigated. The study also attempted to validate the use of the area under the serum response curve (AUC) from food compared with folic acid as a proxy variable for food folate bioavailability. Folate absorption was determined in healthy ileostomy volunteers (n11) using a single-dose short-term protocol. In a randomised crossover design, volunteers received spinach meals and a supplement. Based on analysis of test meals and ileostomy effluents, there was no difference in folate absorption between spinach with a mono-:polyglutamate ratio 40:60 and the same spinach with a 100:0 ratio. The absolute absorption of spinach folate (79 %) calculated from the difference between folate intake and folate content of ileostomy effluents was approximately equal to the relative absorption (81 %) calculated from the AUC after consumption of spinach meals in relation to the AUC after consumption of the folic acid supplement. We conclude that the deconjugation process is not a limiting factor in the absorption of spinach folates. Comparison of AUC of food folatev.folic acid in a short-term protocol may be suitable for assessing food folate bioavailability.

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