56 research outputs found
Consensus for the management of pancreatic exocrine insufficiency: UK practical guidelines.
INTRODUCTION: Pancreatic exocrine insufficiency is a finding in many conditions, predominantly affecting those with chronic pancreatitis, pancreatic cancer and acute necrotising pancreatitis. Patients with pancreatic exocrine insufficiency can experience gastrointestinal symptoms, maldigestion, malnutrition and adverse effects on quality of life and even survival.There is a need for readily accessible, pragmatic advice for healthcare professionals on the management of pancreatic exocrine insufficiency. METHODS AND ANALYSIS: A review of the literature was conducted by a multidisciplinary panel of experts in pancreatology, and recommendations for clinical practice were produced and the strength of the evidence graded. Consensus voting by 48 pancreatic specialists from across the UK took place at the 2019 Annual Meeting of the Pancreatic Society of Great Britain and Ireland annual scientific meeting. RESULTS: Recommendations for clinical practice in the diagnosis, initial management, patient education and long term follow up were developed. All recommendations achieved over 85% consensus and are included within these comprehensive guidelines
Application of the pore water stable isotope method and hydrogeological approaches to characterise a wetland system
Three naturally intact wetland systems (swamps) were
characterised based on sediment cores, analysis of surface water, swamp
groundwater, regional groundwater and pore water stable isotopes. These
swamps are classified as temperate highland peat swamps on sandstone (THPSS)
and in Australia they are listed as threatened endangered ecological
communities under state and federal legislation.
This study applies the stable isotope direct vapour equilibration method in
a wetland, aiming at quantification of the contributions of evaporation,
rainfall and groundwater to swamp water balance. This technique potentially
enables understanding of the depth of evaporative losses and the relative
importance of groundwater flow within the swamp environment without the need
for intrusive piezometer installation at multiple locations and depths.
Additional advantages of the stable isotope direct vapour equilibration
technique include detailed spatial and vertical depth profiles of
δ18O and δ2H, with good accuracy comparable to other
physical and chemical extraction methods.
Depletion of δ18O and δ2H in pore water with
increasing depth (to around 40–60 cm depth) was observed in two swamps but
remained uniform with depth in the third swamp. Within the upper surficial
zone, the measurements respond to seasonal trends and are subject to
evaporation in the capillary zone. Below this depth the pore water
δ18O and δ2H signature approaches that of
regional groundwater, indicating lateral groundwater contribution.
Significant differences were found in stable pore water isotope samples
collected after the dry weather period compared to wet periods where recharge
of depleted rainfall (with low δ18O and δ2H
values) was apparent.
The organic-rich soil in the upper 40 to 60 cm retains significant
saturation following precipitation events and maintains moisture necessary
for ecosystem functioning. An important finding for wetland and ecosystem
response to changing swamp groundwater conditions (and potential ground
movement) is that basal sands are observed to underlay these swamps, allowing
relatively rapid drainage at the base of the swamp and lateral groundwater
contribution.
Based on the novel stable isotope direct vapour equilibration analysis of
swamp sediment, our study identified the following important processes: rapid
infiltration of rainfall to the water table with longer retention of moisture
in the upper 40–60 cm and lateral groundwater flow contribution at the
base. This study also found that evaporation estimated using the stable
isotope direct vapour equilibration method is more realistic compared to
reference evapotranspiration (ET). Importantly, if swamp discharge data were
available in combination with pore water isotope profiles, an appropriate
transpiration rate could be determined for these swamps. Based on the
results, the groundwater contribution to the swamp is a significant and
perhaps dominant component of the water balance. Our methods could complement
other monitoring studies and numerical water balance models to improve
prediction of the hydrological response of the swamp to changes in water
conditions due to natural or anthropogenic influences.</p
The influence of syndepositional macropores on the hydraulic integrity of thick alluvial clay aquitards
Clay-rich deposits are commonly assumed to be aquitards which act as natural hydraulic barriers due to their low hydraulic connectivity. Postdepositional weathering processes are known to increase the permeability of aquitards in the near surface but not impact on deeper parts of relatively thick formations. However, syndepositional processes affecting the hydraulic properties of aquitards have previously received little attention in the literature. Here, we analyze a 31 m deep sediment core recovered from an inland clay-rich sedimentary sequence using a combination of techniques including particle size distribution and microscopy, centrifuge dye tracer testing and micro X-ray CT imaging. Subaerial deposition of soils within these fine grained alluvial deposits has led to the preservation of considerable macropores (root channels or animal burrows). Connected pores and macropores thus account for vertical hydraulic conductivity (K) of 4.2×10-1m/s (geometric mean of 13 samples) throughout the thick aquitard, compared to a matrix K that is likely < 10-10m/s, the minimum K value that was measured. Our testing demonstrates that such syndepositional features may compromise the hydraulic integrity of what otherwise appears to have the characteristics of a much lower permeability aquitard. Heterogeneity within a clay-rich matrix could also enhance vertical connectivity, as indicated by digital analysis of pore morphology in CT images. We highlight that the paleo-environment under which the sediment was deposited must be considered when aquitards are investigated as potential natural hydraulic barriers and illustrate the value of combining multiple investigation techniques for characterizing clay-rich deposits
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