Hydrodynamique d'une pessière noire drainée

1992 ◽  
Vol 22 (8) ◽  
pp. 1063-1070 ◽  
Author(s):  
Pierre Belleau ◽  
André P. Plamondon ◽  
Robert Lagacé ◽  
Steeve Pépin
Keyword(s):  
Hydraulic Conductivity ◽  
Water Table ◽  
Root Zone ◽  
Black Spruce ◽  
Mineral Soil ◽  
Soil Layer ◽  
Drainage Ditches ◽  
Deep Root ◽  
Before And After ◽  
The Mean

The depth of the water table was measured before and after the digging of drainage ditches with 20-, 40-, and 60-m spacings in a black spruce wild holly bog. The peat is mesic with the exception of the top 10 cm which is fibric. The hydraulic conductivity of the 20- to 40-cm layer is low in relation with other Quebec sites under study. The extremely low conductivity under the 40-cm depth and the impermeable mineral soil layer at the bottom of the ditches creates the horizontal profile between ditches. The mean water table depths during the 3 years of the study were 42, 29, and 22 cm, respectively, for the 20-, 40-, and 60-m spacings. The corresponding lowering of the water table was in the order of 25, 13, and 6 cm. The water table was maintained 100, 70, and 40% of the time below the 20 cm deep root zone for the 20-, 40-, and 60-m spacings respectively, compared with 23% for the undrained situation (by simulation). The water table is significantly lowered below the 40-cm threshold for the 20-m spacing only.

Effects of drainage on substrate temperature and phenology of some trees and shrubs in an Alberta peatland

1987 ◽  
Vol 17 (2) ◽  
pp. 97-104 ◽  
Author(s):  
V. J. Lieffers ◽  
R. L. Rothwell
Keyword(s):  
Water Table ◽  
Black Spruce ◽  
North Central ◽  
Air Temperatures ◽  
Dwarf Birch ◽  
Summer Temperatures ◽  
The Mean ◽  
Study Sites ◽  
Individual Trees ◽  
Trees And Shrubs

A 50-ha portion of an intermediate fen in north central Alberta was drained in 1984. Study sites were established in the drained area and in an adjacent undrained area. In each site, seasonal water table depth and substrate and air temperatures were monitored. The drainage lowered the water table from 20 to 50 cm compared with the adjacent undrained site. Substrate of the drained area warmed above 0 °C slightly later than the undrained area but maximum summer temperatures were higher in the drained site. Temperatures in 1985 at the 10-cm depth of the drained site peaked in early August at 15–16 °C, 3–4 °C higher than the undrained site. Forty-five black spruce (Piceamariana (Mill.) B.S.P.), 45 tamarack (Larixlaricina (Du Roi) K. Koch), and 25 dwarf birch (Betulapumila L.) were tagged and examined twice weekly. For tamarack and dwarf birch, flowering and bud flush were significantly earlier by 2–6 days in the drained site. For black spruce, flowering was earlier in the drained site; bud flush, however, was earlier in the undrained site in 1985 but there were no differences between sites in 1986. For both black spruce and tamarack, the mean date at which individual trees reached 50% of total leader elongation was earlier in the drained site in both 1984 and 1985.

Soil oxygen within boreal forests across an age gradient

2006 ◽  
Vol 86 (1) ◽  
pp. 1-9 ◽  
Author(s):  
N. Fenton ◽  
S. Légaré ◽  
Y. Bergeron ◽  
D. Paré
Keyword(s):  
Water Table ◽  
Boreal Forests ◽  
Forest Floor ◽  
Black Spruce ◽  
Methodological Issue ◽  
Mineral Soil ◽  
Forest Region ◽  
Feather Mosses ◽  
Spruce Stands ◽  
Potential Factors

Globally, soil anoxia and water table rise play a role in the development of peatlands from forests. Cited causes have included a diversity of internal and external mechanisms, including Sphagnum and feather mosses, hardpan development, and peatland expansion. The objectives of this study were to examine water table depth in black spruce stands of the Clay Belt of Quebec and Ontario, and to associate changes with potential stand scale causal factors (primarily biological). A methodological issue, the link between oxygen zone and water table, was also addressed. Within stands less than 100 yr post-fire, oxygen zone and water table position were only loosely related, and no other potential factors were significantly correlated. Across a chronosequence of stands, while oxygen zone thickness in the soil profile was relatively constant, its position relative to the mineral soil changed, as it rose from the mineral soil into the forest floor. Forest floor thickness was the dominant explanatory factor in oxygen zone position, suggesting that in these forests other postulated mechanisms are less important. At the landscape level, the movement of the oxygen zone into the forest floor has important consequences for the long-term productivity of this intensively exploited forest region. Key words: Water table, black spruce, paludification, forest floor, Clay Belt, Sphagnum

scholarly journals Temporal variation in depth to water table and hydrochemistry in three raised bogs and their laggs in coastal British Columbia, Canada

2012 ◽  
Vol 9 (12) ◽  
pp. 14065-14107 ◽  
Author(s):  
S. A. Howie ◽  
H. J. van Meerveld
Keyword(s):  
British Columbia ◽  
Temporal Variation ◽  
Water Table ◽  
Mineral Soil ◽  
Raised Bog ◽  
Raised Bogs ◽  
Depth To Water Table ◽  
Mean Water Level ◽  
The Mean ◽  
Coastal British Columbia

Abstract. The laggs of three raised bogs in coastal British Columbia were studied in 2010–2012 to determine the temporal variation in depth to water table and hydrochemistry. The lagg is an integral, but rarely studied, part of a raised bog that helps to maintain the water mound in the bog and provides a buffer for runoff from adjacent mineral areas. Depth to water table measurements in 25 piezometers displayed similar annual fluctuations, with the highest water table in winter and the lowest at the end of summer. The smallest fluctuations in depth to water table were recorded closest to the bog centre, and the largest fluctuations in the laggs and adjacent mineral soil sites. Removal of a mature forest stand on one of the study transects resulted in a "watering-up" of the lagg site; the mean water level between August and November increased by 8 cm from 2010 to 2011, and by up to 27 cm during the driest time of the year. pH, pH-corrected electrical conductivity, and Na+ and Mg2+ concentrations varied little during the study period, whereas Ca2+, K+, Cl−, and DOC concentrations and acidity were more variable.

scholarly journals Temporal water table changes in soil toposequence of the Poznań Lakeland (western Poland)

2017 ◽  
Vol 68 (4) ◽  
pp. 167-173
Author(s):  
Michał Kozłowski ◽  
Jolanta Komisarek
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Water Table ◽  
Root Zone ◽  
Linear Regression Analysis ◽  
Temporal Trends ◽  
Water Table Depth ◽  
The Mean ◽  
The Impact

Abstract The paper presents results of determination of temporal changes in water table depths in the toposequence of Retisols/Luvisols and Phaeozems/Gleysols. Assessment of temporal trends in the water table depth was made with the use of the linear regression analysis. The results obtained indicate that the mean water table depth and mean high and low water table depths were deeper in the soil at the upper part of the slope in comparison with soil located at the footslope. A higher amplitude of water table was observed in Retisols than in Gleysols but the highest variability of water table level was noted in the soils at the footslope compared to those at the slope summit. In Retisols, with each month of observation from 1993 to 2012, the water table showed a tendency to increase. These trends were the highest from January to April, which may be related to the tendency of increasing monthly sums of precipitation in December, January and February. In the Gleysol at the footslope, in the period 1993–2012 and in the vegetation season, the water table depth showed a tendency to decrease. This trend may be due to the impact of water table on the soil water content at the root zone, which is used in the process of evapotranspiration.

Microrelief, Water Level Fluctuations, and Diameter Growth in Wet-site Stands of Red and Black Spruce in New Brunswick

1975 ◽  
Vol 5 (3) ◽  
pp. 359-366 ◽  
Author(s):  
H. van Groenewoud
Keyword(s):  
Water Table ◽  
Black Spruce ◽  
Maximum Growth ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Diameter Growth ◽  
Tree Diameter ◽  
Growing Seasons ◽  
Average Water ◽  
The Mean

Soil water levels, rainfall, and tree diameter increments were measured during four successive growing seasons. Microrelief data and depth of the fluctuating water tables were incorporated into a measure of mean soil depth.Water table fluctuations were closely linked to rainfall. Deviations from the mean tree diameter growth were related to deviations from the mean depth of the water table. Maximum growth took place at the mean depth of the water table, with decreases in growth at higher or lower than average water levels.

Perbedaan Pengetahuan Siswa Tentang Penyakit Hepatitis A Sebelum Dan Sesudah Penyuluhan Di MTsN 02 Bondowoso Tahun 2015

2017 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Putri Megasari
Keyword(s):  
Hepatitis A ◽  
Hepatitis Virus ◽  
Sampling Technique ◽  
Mean Value ◽  
Test Design ◽  
The World ◽  
Before And After ◽  
Post Test ◽  
The Mean ◽  
Paired T Test

Hepatitis has become a health problem in the world. The hepatitis virus infected many people. According to the teacher of MTsN 02 Bondowoso more than 20 students have hepatitis A viral infection. The purpose of this research was to know the differences of students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study used pre-experimental (pre-post test design). This study used stratified random sampling technique, 127 students from 270 sample involved this research,and 143 students was excluded. We used questionnaires to collect data. The results showed that the mean value of the students 'knowledge about hepatitis A before counseling in MTsN 02 Bondowoso 2015 was 83.96 with the lowest value of 37.5 and the highest value was 100. The mean value of the students' knowledge about hepatitis A after counseling in MTsN 02 Bondowoso 2015 was 93.21 with the lowest value waf 62.5 and the highest value was 100. Paired t test showed that t (-9.07) > t table (1.98), the null hypothesis (H0) was rejected. There was a difference between students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study showed that routine counseling by healthcare provider was important to prevent hepatitis A infection.; Keywords: counseling, knowledge of students, hepatitis

EFFECT OF SPATIAL VARIABILITY IN HYDRAULIC CONDUCTIVITY ON WATER TABLE DRAWDOWN

1997 ◽  
Vol 40 (2) ◽  
pp. 371-375
Author(s):  
S. O. Prasher ◽  
M. Singh ◽  
A. K. Maheshwari ◽  
R. S. Clemente
Keyword(s):  
Hydraulic Conductivity ◽  
Spatial Variability ◽  
Water Table

Quality of Life for Children with Persistent Sinonasal Symptoms

2003 ◽  
Vol 128 (1) ◽  
pp. 17-26 ◽  
Author(s):  
David J. Kay ◽  
Richard M. Rosenfeld
Keyword(s):  
Quality Of Life ◽  
Clinical Care ◽  
Longitudinal Change ◽  
Good Test ◽  
Routine Clinical Care ◽  
Before And After ◽  
The Mean ◽  
The Individual ◽  
Sinonasal Symptoms

OBJECTIVE: The goal was to validate the SN-5 survey as a measure of longitudinal change in health-related quality of life (HRQoL) for children with persistent sinonasal symptoms. DESIGN AND SETTING: We conducted a before and after study of 85 children aged 2 to 12 years in a metropolitan pediatric otolaryngology practice. Caregivers completed the SN-5 survey at entry and at least 4 weeks later. The survey included 5 symptom-cluster items covering the domains of sinus infection, nasal obstruction, allergy symptoms, emotional distress, and activity limitations. RESULTS: Good test-retest reliability ( R = 0.70) was obtained for the overall SN-5 score and the individual survey items ( R ≥ 0.58). The mean baseline SN-5 score was 3.8 (SD, 1.0) of a maximum of 7.0, with higher scores indicating poorer HRQoL. All SN-5 items had adequate correlation ( R ≥ 0.36) with external constructs. The mean change in SN-5 score after routine clinical care was 0.88 (SD, 1.19) with an effect size of 0.74 indicating good responsiveness to longitudinal change. The change scores correlated appropriately with changes in related external constructs ( R ≥ 0.42). CONCLUSIONS: The SN-5 is a valid, reliable, and responsive measure of HRQoL for children with persistent sinonasal symptoms, suitable for use in outcomes studies and routine clinical care.

scholarly journals Evaluation of pharmacy-led weight management service to minimise the risk of cardiovascular disease

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Aliki Peletidi ◽  
Reem Kayyali
Keyword(s):  
Physical Activity ◽  
Weight Management ◽  
Activity Levels ◽  
Management Service ◽  
Initial Weight ◽  
Public Health Services ◽  
Clinical Role ◽  
Physical Activity Levels ◽  
Before And After ◽  
The Mean

Abstract Aims The primary aim of the programme was a minimum of a 5% weight reduction of the initial weight, while the secondary outcomes were a reduction in participants’ body mass index (BMI), waist circumference (WC), blood pressure (BP), AUDIT-C score and an increase in the Mediterranean diet (MD) score and an improvement in physical activity levels. Methods This 'before and after' study was a 10-week weight management (WM) programme and it was developed and delivered in community pharmacies in Patras chosen for convenience, thus consisting the first service of its type in Greece. The sample size was calculated (n = 96) based on the mean BMI for a Greek male and female individual, and the standard deviation (SD) of weight at baseline of 14 kg. Results Nearly every participant enrolled in the 20 participating pharmacies, 97.4% (n = 114/117), achieved the programme’s aim, losing at least 5% of their initial weight. The mean percentage of total weight loss of the 117 participants at the 10th week was 8.97% (SD 2.65), and the t-test showed statistically significant results (P-value < 0.001; 95% CI [8.48, 9.45]). A significant reduction in the waist-to-height ratio (WHtR) was observed in both male (P-value = 0.004) and female (P-value < 0.001) participants. The participants’ BP and AUDIT-C score and physical activity levels significantly improved (P-value < 0.001), as well as their MD score. Conclusion This study provides the first evidence that Greek pharmacists have the potential to play an important role within primary healthcare and that after training they are able to provide public health services for both the public’s benefit and their clinical role enhancement.

scholarly journals CT perfusion in peripheral arterial disease—hemodynamic differences before and after revascularisation

2021 ◽  
Author(s):  
Patrick Veit-Haibach ◽  
Martin W. Huellner ◽  
Martin Banyai ◽  
Sebastian Mafeld ◽  
Johannes Heverhagen ◽  
...  
Keyword(s):  
Peripheral Arterial Disease ◽  
Ct Perfusion ◽  
Arterial Disease ◽  
Lower Leg ◽  
Therapy Control ◽  
Non Invasive ◽  
Before And After ◽  
Invasive Method ◽  
The Mean ◽  
Peripheral Arterial

Abstract Objectives The purpose of this study was the assessment of volumetric CT perfusion (CTP) of the lower leg musculature in patients with symptomatic peripheral arterial disease (PAD) before and after interventional revascularisation. Methods Twenty-nine consecutive patients with symptomatic PAD of the lower extremities requiring interventional revascularisation were assessed prospectively. All patients underwent a CTP scan of the lower leg, and hemodynamic and angiographic assessment, before and after intervention. Ankle-brachial pressure index (ABI) was determined. CTP parameters were calculated with a perfusion software, acting on a no outflow assumption. A sequential two-compartment model was used. Differences in CTP parameters were assessed with non-parametric tests. Results The cohort consisted of 24 subjects with an occlusion, and five with a high-grade stenosis. The mean blood flow before/after (BFpre and BFpost, respectively) was 7.42 ± 2.66 and 10.95 ± 6.64 ml/100 ml*min−1. The mean blood volume before/after (BVpre and BVpost, respectively) was 0.71 ± 0.35 and 1.25 ± 1.07 ml/100 ml. BFpost and BVpost were significantly higher than BFpre and BVpre in the treated limb (p = 0.003 and 0.02, respectively), but not in the untreated limb (p = 0.641 and 0.719, respectively). Conclusions CTP seems feasible for assessing hemodynamic differences in calf muscles before and after revascularisation in patients with symptomatic PAD. We could show that CTP parameters BF and BV are significantly increased after revascularisation of the symptomatic limb. In the future, this quantitative method might serve as a non-invasive method for surveillance and therapy control of patients with peripheral arterial disease. Key Points • CTP imaging of the lower limb in patients with symptomatic PAD seems feasible for assessing hemodynamic differences before and after revascularisation in PAD patients. • This quantitative method might serve as a non-invasive method, for surveillance and therapy control of patients with PAD.

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