scholarly journals Uncertainty in mass-balance trends derived from altimetry: a case study along the EGIG line, central Greenland

2015 ◽  
Vol 61 (226) ◽  
pp. 345-356 ◽  
Author(s):  
Elizabeth M. Morris ◽  
Duncan J. Wingham
Keyword(s):  
Mass Balance ◽  
Greenland Ice Sheet ◽  
Repeated Measurements ◽  
Elevation Change ◽  
Short Term ◽  
Density Profiles ◽  
Mean Values ◽  
Equivalent Mass ◽  
The Mean

AbstractRepeated measurements of density profiles and surface elevation along a 515 km traverse of the Greenland ice sheet are used to determine elevation change rates and the error in determining mass-balance trends from these rates which arises from short-term fluctuations in mass input, compaction and surface density. Mean values of this error, averaged over 100 km sections of the traverse, decrease with time from the start of observations in 2004, with a half-time of ∼4 years. After 7 years the mean error is less than the ice equivalent mass imbalance.

scholarly journals The effect of fluctuations in surface density, accumulation and compaction on elevation change rates along the EGIG line, central Greenland

2011 ◽  
Vol 57 (203) ◽  
pp. 416-430 ◽  
Author(s):  
Elizabeth M. Morris ◽  
Duncan J. Wingham
Keyword(s):  
Mass Balance ◽  
Surface Density ◽  
Greenland Ice Sheet ◽  
Repeated Measurements ◽  
Average Error ◽  
Radar Altimeter ◽  
Elevation Change ◽  
Short Term ◽  
Density Profiles ◽  
Time Period

AbstractRepeated measurements of density profiles and surface elevation along a 515 km section of the Greenland ice sheet have been used to determine elevation change rates and the error in determining mass balance from these rates which arises from short-term fluctuations in mass input, compaction and surface density. Over the 28 months from spring 2004 to summer 2006 the average error over 100 km sections of the traverse ranged from −0.006 to 0.100 ma−1. The lowest values, comparable with the system accuracy of the CryoSat radar altimeter (0.033 m a−1), were found below 3000 m. The surface density required to translate the elevation change into mass change decreased from 0.40 g cm−3 at an elevation of 2348 m to 0.33 g cm−3 at an elevation of 3264 m. From the density profiles the equivalent values for a time period of 10 years were found to be 0.48 and 0.38 g cm−3, respectively.

Validation of a new algorithm for the short-term variation of the fetal heart rate: an antepartum prospective study

2018 ◽  
Vol 46 (6) ◽  
pp. 599-604 ◽  
Author(s):  
Christina Kouskouti ◽  
Hella Jonas ◽  
Kerstin Regner ◽  
Pia Ruisinger ◽  
Julia Knabl ◽  
...  
Keyword(s):  
Heart Rate ◽  
Reference Values ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Normal Values ◽  
Short Term ◽  
Mean Values ◽  
Relevant Reference ◽  
Term Variation ◽  
The Mean

Abstract Aims: Currently one of the most widespread systems for the computerized analysis of the fetal heart rate (FHR) is the Dawes-Redman system, where the short-term variation (STV) of the FHR is measured by dividing each minute into 16 segments (STV16). Technical progress has allowed for the development of a new algorithm, which measures the STV by dividing each minute into 240 segments (STV240), thus approximating the beat-to-beat variation. The STV240 still lacks reference values. Our aim was to develop clinically relevant reference values for the STV240 and compare them to the ones for the STV16. Methods: In a single centre, observational study, a total of 228 cardiotocograms were registered and subsequently analyzed with both algorithms (STV240 and STV16). Results: The 95% confidence interval (CI) was calculated for both algorithms. The values of the STV240 were significantly lower in comparison to the ones of the STV16. Not only the mean values but also the 95th percentile of the STV240 lay beneath the existent cut-off value for the STV16. Conclusions: Every clinician using the new algorithm must be aware that the normal values for the STV240 lie beneath the, up until now, established cut-off values for the STV16.

scholarly journals Efficacy of Gluma Desensitizer® on dentin hypersensitivity in periodontally treated patients

2006 ◽  
Vol 20 (3) ◽  
pp. 252-256 ◽  
Author(s):  
Camila de Azevedo de Assis ◽  
Raquel Pippi Antoniazzi ◽  
Fabrício Batistin Zanatta ◽  
Cassiano Kuchenbecker Rösing
Keyword(s):  
Repeated Measurements ◽  
Group Differences ◽  
Dentin Hypersensitivity ◽  
Single Application ◽  
Double Blind ◽  
Mean Values ◽  
The Mean ◽  
Tactile Probe ◽  
And Control ◽  
Paired T Test

The aim of this double-blind, controlled, split-mouth designed clinical trial was to assess the effect of a single application of Gluma Desensitizer® on alleviating dentin hypersensitivity. Twelve subjects entered the study and ten completed the protocol. Each subject had two teeth treated: one with Gluma Desensitizer® according to the manufacturer's instructions and one with water. The assessment of pain was performed with the VAS (Visual Analogue Scale), after tactile (probe), thermal (cold blast of water) and thermal/evaporative (cold blast of air) stimuli at baseline, immediately after treatment, after 1 week and after 4 weeks. The mean VAS values for the test and control teeth were compared by the paired t test (alpha = 0.05). Repeated measurements ANOVA was used to compare the different experimental times. The results showed that for test teeth, at baseline, mean VAS values were 1.76 (± 2.82), 7.10 (± 2.10) and 4.75 (± 2.65), and, after 4 weeks, the mean values were 1.70 (± 2.31), 5.50 (± 3.30) and 4.61 (± 3.14), respectively for probe, water and air stimuli. For the control teeth, at baseline, the mean VAS values were 1.86 (± 2.92), 6.61 (± 2.31) and 4.08 (± 2.91) and, after 4 weeks, 2.66 (± 3.07), 6.32 (± 2.94) e 4.76 (± 3.26).There were no statistically significant differences between test and control teeth at any time. No intra-group differences were demonstrated either. It was concluded that Gluma Desensitizer® had no effect on hypersensitive teeth from periodontally treated patients for a period up to 4 weeks.

scholarly journals Reduced melt on debris-covered glaciers: investigations from Changri Nup Glacier, Nepal

2016 ◽  
Author(s):  
C. Vincent ◽  
P. Wagnon ◽  
J. M. Shea ◽  
W. W. Immerzel ◽  
P. D. A. Kraaijenbrink ◽  
...  
Keyword(s):  
Mass Balance ◽  
Surface Mass Balance ◽  
Mass Balances ◽  
Elevation Change ◽  
Surface Mass ◽  
Future Evolution ◽  
Debris Cover ◽  
Aerial Vehicle ◽  
The Mean ◽  
Terrestrial Photogrammetry

Abstract. Debris-covered glaciers occupy more than 1/4 of the total glacierized area in the Everest region of Nepal, yet the surface mass balance of these glaciers has not been measured directly. In this study, ground-based measurements of surface elevation and ice depth are combined with terrestrial photogrammetry and unmanned aerial vehicle (UAV) elevation models to derive the surface mass balance of the debris-covered Changri Nup Glacier, located in the Everest region. Over the debris-covered tongue, the mean elevation change between 2011 and 2015 is −0.93 m ice/year or −0.84 m water equivalent per year (w.e. a−1). The mean emergence velocity over this region, estimated from the total ice flux through a cross-section immediately above the debris-covered zone, is +0.37 m w.e. a−1. The debris-covered portion of the glacier thus has an area-averaged mass balance of −1.21 ± 0.2 m w.e. a−1 between 5240 and 5525 m above sea level (m a.s.l.). The surface mass balances observed on nearby debris-free glaciers suggest that the ablation is strongly reduced (by ca. 1.8 m w.e. a−1) by the debris cover. The insulating effect of the debris cover largely dominates the enhanced ice ablation due to the supra-glacial ponds and exposed ice cliffs. This finding has major implications for modeling the future evolution of debris-covered glaciers.

scholarly journals Modelling albedo and specific balance of the Greenland ice sheet: calculations for the Søndre Strømfjord transect

1996 ◽  
Vol 42 (141) ◽  
pp. 305-317 ◽  
Author(s):  
Z. Zuo ◽  
J. Oerlemans
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Air Temperature ◽  
Surface Albedo ◽  
Meteorological Data ◽  
Greenland Ice Sheet ◽  
Mass Balance Models ◽  
The Mean ◽  
Energy Balance Models ◽  
Wide Zone

AbstractGlacio-meteorological data obtained during the Greenland Ice Margin Experiment (GIMEX) investigations in West Greenland (the Søndre Strømfjord transect) have been used to test and calibrate energy-balance/mass-balance models for the ice/snow surface. The region is characterised by the development of a wide zone of low surface albedo in the course of the melting season. This zone was simulated in one of the energy-balance models by including the effect of surficial meltwater on albedo. Observed mass-balance and albedo data were used to constrain the models. Although all the models are capable of predicting the transect balance reasonably well, only the model with the meltwater albedo coupling, is able to reproduce the observed albedo pattern and mass-balance profile along the transect. By including the feedback between surficial meltwater and albedo in the model, the sensitivity of the specific balance to changes in air temperature is found to be greatest just below the equilibrium line (in contrast to what is generally found for valley glaciers). A 1 K warming of the air temperature would increase the mean ablation along the transect by 0.5 m w.e.year −1.

scholarly journals Profiling students’ environmental care attitudes taught using Sasak Tribe local wisdom-integrated model

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
H. Hunaepi ◽  
Ika Nuraini Dewi ◽  
S. Sumarjan
Keyword(s):  
Sampling Technique ◽  
Integrated Model ◽  
Descriptive Statistics ◽  
Central Tendency ◽  
Mean Values ◽  
Environmental Care ◽  
Descriptive Research ◽  
Analysis Technique ◽  
The Mean

Sasak Tribe possesses unique local wisdom which is potential to be utilized in term of improving students' care attitudes toward the environment. This study aimed at profiling students' evironmental attitudes who were taught using Sasak Tribe local wisdom-integrated model. This descriptive research was designed with a one-shot case study. The sample used in this study was 140 VII graders chosen using random sampling technique. The sample comprised of 3 classes of SMPN 2 Gunung Sari and 3 classes of SMPN 3 Lingsar placed in West Nusa Tenggara-Indonesia. The data analysis technique used was descriptive statistics in term of central tendency. The measured indicators were environmental awareness (EA), developing empathy (DE), and effect handling (EH). The results showed that the students live in suburb area tended to have better environmental care attitudes, in which the mean values were 86.66 (EA), 75.69 (DE), and 42.66 (EH) compared to those who live in urban area in which the mean values were 68.73 (EA), 57.07 (DE), and 30.62 (EH). Based on this findings, further evaluation in several aspects should be done.

Short-term vestibular responses to repeated rotations

2000 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
Seung Cheol Ahn ◽  
Chae Yong Lee ◽  
Dong Wook Kim ◽  
Moo Hoo Lee
Keyword(s):  
Time Constant ◽  
Phase Changes ◽  
Short Term ◽  
Mean Values ◽  
Ocular Reflex ◽  
Group I ◽  
Vestibulo Ocular Reflex ◽  
The Mean ◽  
Group Ii ◽  
Sinusoidal Rotations

To investigate the short-term vestibular habituation, we performed the 4 successive velocity step tests on 28 volunteers, the peak velocity of which was 100 deg/sec with acceleration and deceleration of 100 deg / sec 2 . As the repeated rotations might alter the vestibulo-ocular reflex (VOR), sinusoidal rotations at a frequency of 0.16 Hz were also given before and after the 4 successive velocity step tests to investigate the changes of gain and phase of VOR. The 28 volunteers were divided into two groups, group I and II, according to their responses to repeated rotations. In group I (25 subjects, mean age 23.7 year), the mean values of the slow cumulative eye position (SCEP), the time integral of eye velocity during nystagmus, was reduced after each trial of the 4-successive velocity step tests as follows; 403.4 ± 29 degree (1st trial), 346.2 ± 37 degree (2nd trial), 278.3 ± 33 degree (3rd trial) and 256.6 ± 36 degree (4th trial). The time constant of the nystagmus was also reduced as follows; 12.9 ± 0.78 second (1st trial), 12 ± 0.63 second (2nd trial), 9.7 ± 0.78 second (3rd trial) and 9.9 ± 0.54 second (4th trial). In group II (3 subjects, mean age 28.3 year), the mean values of SCEP gradually increased; 774.3 ± 135 degree (1st trial), 1127 ± 178 degree (2nd trial), 1096.3 ± 123.4 degree (3rd trial) and 1225.7 ± 199.7 degree (4th trial). The time constant of the nystagmus increased; 15.7 ± 2.7 second (1st trial), 22 ± 4.5 second (2nd trial), 22.3 ± 3.3 second (3rd trial) and 23.3 ± 5.7 second (4th trial). The gain of vestibulo-ocular reflex (VOR) induced by sinusoidal rotations at a frequency 0.16 Hz increased in both groups: 0.59 ± 0.03 to 0.78 ± 0.06 (group I) and 0.65 ± 0.07 to 1.15 ± 0.06 (group II). Phase changes were also observed. In group I, the phase was shifted from 0.6 ± 0.6 degree to − 0.40 ± 0.6 degree. In group II, the phase was shifted from 3.67 ± 1.86 degree to − 0.33 ± 0.33 degree. The repeated rotation did not induce a common nystagmic response in all subjects. Thus, person to person variations should be considered in short term vestibular habituation.

scholarly journals Class II subdivision treatment with the Herbst appliance

2012 ◽  
Vol 83 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Niko C. Bock ◽  
Benjamin Reiser ◽  
Sabine Ruf
Keyword(s):  
Class Ii ◽  
Class I ◽  
Class Iii ◽  
Midline Shift ◽  
Herbst Appliance ◽  
Short Term ◽  
Retention Period ◽  
Mean Values ◽  
The Mean ◽  
Original Class

ABSTRACT Objective: To assess the effectiveness of Class II subdivision Herbst nonextraction treatment and its short-term stability retrospectively. Materials and Methods: Twenty-two Class II subdivision (SUB: right-left molar difference ≥0.75 cusp width) and 22 symmetric Class II patients (SYM: ≥0.75 cusp width bilaterally) were matched according to gender and pretreatment handwrist radiographic stage. The mean treatment duration of the Herbst and subsequent multibracket phase was 8 months and 14 months, respectively. The mean retention period amounted to 36 months. Dental casts from before treatment (T1), after Herbst treatment (T2), after Multibracket treatment (T3), and after retention (T4) were evaluated. Results: A bilateral Class I or super Class I molar relationship was seen in 72.7% (SUB) and 77.3% (SYM) at T3. The corresponding values at T4 were 63.7% (SUB) and 72.7% (SYM). A unilateral or bilateral Class III molar relationship was more frequent in the SUB group (T3: +4.6%; T4: +13.6%). For overjet, similar mean values were seen in both groups after treatment (T3: SUB, 2.7 mm; SYM, 2.3 mm) and after retention (T4: SUB, 3.0 mm; SYM, 3.4 mm). This was also true for the midline shift (T3: SUB, −0.4 mm; SYM, 0.0 mm; T4: SUB, −0.3 mm; SYM, 0.0 mm). Conclusion: Class II subdivision Herbst treatment was successful similarly to symmetric Class II Herbst treatment. However, a slight overcompensation of the molar relationship (Class III tendency) was more frequent in the subdivision patients (original Class I side).

Rapid adaptations of serum thyrotrophin, triiodothyronine and reverse triiodothyronine levels to short-term starvation and refeeding

1984 ◽  
Vol 105 (2) ◽  
pp. 194-199 ◽  
Author(s):  
Jean-Noel Hugues ◽  
Albert G. Burger ◽  
A. Eugene Pekary ◽  
Jerome M. Hershman
Keyword(s):  
Serum Cortisol ◽  
Starvation Period ◽  
Short Term ◽  
Mean Values ◽  
Fed State ◽  
Tsh Secretion ◽  
The Mean ◽  
Serum Tsh ◽  
Tsh Levels

Abstract. Nutrition influences thyroid function at the level of TSH secretion, at the level of monodeiodination, and possibly elsewhere. In order to study the effect of starvation on TSH secretion, 8 healthy male volunteers fasted for 30 h and were then refed with 800 kcal. Refeeding was performed at 19.00 h and blood was sampled at 20 min intervals until midnight. Control experiments were performed in the same subjects both when they were normally fed and when the starvation period was prolonged a further 5 h until midnight. Starvation decreased serum TSH levels to below 1 mU/l, and without refeeding the nocturnal peak of the TSH nycthemeral rhythm was abolished. With refeeding serum TSH tended to increase towards midnight and was significantly higher than during starvation. However, the serum TSH levels remained significantly below those at the same time of the day in the absence of a preceding starvation period. Serum T3 levels were significantly lower than in the fed state. The mean values were 1.84 ± 0.03 vs 2.30 ± 0.06 nmol/l (120 ±2 vs 150 ± 4 ng/100 ml, mean ± sem P < 0.01). Refeeding did not result in a measurable change in serum T3 concentration (1.80 ± 0.05 nmol/l; 120 ± 3 ng/100 ml, mean ± sem, n.s.). The contrary was true for rT3 levels which increased in starvation and tended to fall with refeeding, but this decrease was not significant. As glucocorticoids have been implicated in the control of monodeiodination and TSH secretion, serum cortisol levels were also measured. They did not differ during the 3 experimental periods. The results show that short-term starvation and refeeding may be a valuable tool for studying in vivo control of TSH secretion. The results show that short-term starvation and refeeding may be a valuable tool for studying in vivo control of TSH secretion.

scholarly journals Elevation change of the Greenland Ice Sheet due to surface mass balance and firn processes, 1960–2014

2015 ◽  
Vol 9 (6) ◽  
pp. 2009-2025 ◽  
Author(s):  
P. Kuipers Munneke ◽  
S. R. M. Ligtenberg ◽  
B. P. Y. Noël ◽  
I. M. Howat ◽  
J. E. Box ◽  
...  
Keyword(s):  
Mass Balance ◽  
Volume Change ◽  
Climate Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Elevation ◽  
Surface Mass Balance ◽  
Elevation Change ◽  
Ice Dynamics ◽  
Surface Mass

Abstract. Observed changes in the surface elevation of the Greenland Ice Sheet are caused by ice dynamics, basal elevation change, basal melt, surface mass balance (SMB) variability, and by compaction of the overlying firn. The last two contributions are quantified here using a firn model that includes compaction, meltwater percolation, and refreezing. The model is forced with surface mass fluxes and temperature from a regional climate model for the period 1960–2014. The model results agree with observations of surface density, density profiles from 62 firn cores, and altimetric observations from regions where ice-dynamical surface height changes are likely small. In areas with strong surface melt, the firn model overestimates density. We find that the firn layer in the high interior is generally thickening slowly (1–5 cm yr−1). In the percolation and ablation areas, firn and SMB processes account for a surface elevation lowering of up to 20–50 cm yr−1. Most of this firn-induced marginal thinning is caused by an increase in melt since the mid-1990s and partly compensated by an increase in the accumulation of fresh snow around most of the ice sheet. The total firn and ice volume change between 1980 and 2014 is estimated at −3295 ± 1030 km3 due to firn and SMB changes, corresponding to an ice-sheet average thinning of 1.96 ± 0.61 m. Most of this volume decrease occurred after 1995. The computed changes in surface elevation can be used to partition altimetrically observed volume change into surface mass balance and ice-dynamically related mass changes.

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