depletion period
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2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Elisabetta Toti ◽  
C.-Y. Oliver Chen ◽  
Maura Palmery ◽  
Débora Villaño Valencia ◽  
Ilaria Peluso

Vegetables and fruits contain non-provitamin A (lycopene, lutein, and zeaxanthin) and provitamin A (β-carotene, β-cryptoxanthin, and α-carotene) carotenoids. Within these compounds, β-carotene has been extensively studied for its health benefits, but its supplementation at doses higher than recommended intakes induces adverse effects. β-Carotene is converted to retinoic acid (RA), a well-known immunomodulatory molecule. Human interventions suggest that β-carotene and lycopene at pharmacological doses affect immune functions after a depletion period of low carotenoid diet. However, these effects appear unrelated to carotenoids and retinol levels in plasma. Local production of RA in the gut-associated lymphoid tissue, as well as the dependency of RA-induced effects on local inflammation, suggests that personalized nutrition/supplementation should be considered in the future. On the other hand, the differential effect of RA and lycopene on transforming growth factor-beta suggests that lycopene supplementation could improve immune functions without increasing risk for cancers. However, such preclinical evidence must be confirmed in human interventions before any recommendations can be made.


2015 ◽  
Vol 16 (3) ◽  
pp. 513 ◽  
Author(s):  
S. KELLER ◽  
J.-P. ROBIN ◽  
M. VALLS ◽  
M. GRAS ◽  
M. CABANELLAS-REBOREDO ◽  
...  

Fuelled by the raising importance of cephalopod fisheries in Europe, there have been demands from scientists and stakeholders for their assessment and management. However, little has been done to improve the data collection in order to analyse cephalopod populations under the EU Data Collection Framework (DCF). While the DCF allows member states to design flexible national sampling programmes, it establishes the minimum data requirements (MDR) each state is obliged to fulfil. In this study, it was investigated whether such MDR currently set by the DCF allow the application of depletion models (DMs) to assess European cephalopod stocks. Squid and cuttlefish fisheries from the western Mediterranean were used as a case study. This exercise sheds doubt on the suitability of the MDR to properly assess and manage cephalopod stocks by means of DMs. Owing to the high plasticity of life-history traits in cephalopod populations, biological parameters should be estimated during the actual depletion period of the fished stocks, in contrast with the triennial sampling established by the DCF. In order to accurately track the depletion event, the rapid growth rates of cephalopods implies that their populations should be monitored at shorter time scales (ideally weekly or biweekly) instead of quarterly as required by the DCF. These measures would not demand additional resources of the ongoing DCF, but a redistribution of sampling efforts during the depletion period. Such changes in the sampling scheme could be designed and undertaken by the member states or directly integrated as requirements.


Author(s):  
Mojtaba P. Shahri ◽  
Stefan Z. Miska

There has been an increasing consciousness regarding stress changes associated with reservoir depletion as the industry moves towards more challenging jobs in deep-water or depleted reservoirs. These stress changes play a significant role in the design of wells in this condition. Therefore, accurate prediction of reservoir stress path, i.e., change in horizontal stresses with pore pressure, is of vital importance. In this study, the current stress path formulation is investigated using a Tri-axial Rock Mechanics Testing Facility. The reservoir depletion scenario is simulated through experiments and provides a better perspective on the currently used formulation and how it’s applicable during production and injection periods. The effect of fluid re-injection into reservoirs on the horizontal stress is also analyzed using core samples. According to the results, formation fracture pressure would not be equal to its initial value if pressure builds up using re-injection. The irrecoverable formation fracture pressure has a power law relation with pore pressure drawdown range. In order to avoid higher permanent fracture pressure reduction, it’s recommended to start the injection process as soon as possible during the production life of reservoirs. According to the experimental results, rocks behave differently during production and injection periods. Poisson’s ratio is greater during pressure build-up as compared to the depletion period. According to the current industry standards, Poisson’s ratio is usually obtained using fracturing data; i.e., leak-off test or mini-fracture test, or well logging methods. However, we are not able to use the same Poisson’s ratio for both pressure drawdown and build-up scenarios according to the experimental data. Corresponding to Poisson’s ratio values, the change in horizontal stress with pore pressure during drawdown (production) is higher than during build-up (injection) period. The outcomes of this study can significantly contribute to well planning and design of challenging wells over the life of reservoirs.


2014 ◽  
Vol 112 (2) ◽  
pp. 162-169 ◽  
Author(s):  
Kara A. Bresnahan ◽  
Christopher R. Davis ◽  
Sherry A. Tanumihardjo

Provitamin A biofortification of staple crops may decrease the prevalence of vitamin A (VA) deficiency if widely adopted in target countries. To assess the impact of processing methods on the VA value of plant foods, the unique bioefficacies ofcis-βC isomers (formed during cooking) compared with all-trans(at) β-carotene (βC) must be determined. The bioefficacies of 9-cis(9c)- and 13-cis(13c)-βC isomers were compared with those of the at-βC isomer and VA positive (VA+) and negative (VA − ) controls in VA-depleted Mongolian gerbils (Meriones unguiculatus) in two experimental studies (study 1,n56; study 2,n57). A 3- or 4-week depletion period was followed by a 3- or 4-week treatment period in which the groups received oral doses of the 9c-, 13c- or at-βC isomers in cottonseed oil (study 1, 15 nmol/d; study 2, 30 nmol/d). In study 1, the βC isomers did not maintain baseline liver VA stores in all groups (0·69 (sd0·20) μmol/liver) except in the VA+group (0·56 (sd0·10) μmol/liver) (P= 0·0026). The βC groups were similar to the VA+group, but the 9c- and 13c-βC groups did not differ from the VA − group (0·39 (sd0·09) μmol/liver). In study 2, the βC isomers maintained baseline liver VA stores in all the βC groups (0·35 (sd0·13) μmol/liver), and in the VA+group, the VA supplement (0·54 (sd0·19) μmol/liver) exceeded the baseline VA status (0·38 (sd0·15) μmol/liver) (P< 0·0001); however, the 9c-βC group did not differ from the VA − group (0·20 (sd0·07) μmol/liver).In vivoisomerisation of βC was confirmed in both experimental studies. Lower VA bioconversion factor values were obtained for thecis-βC isomers in study 2 when compared with study 1, but higher values were obtained for the at-βC isomer. Dose and VA status clearly affect bioconversion factors. In conclusion, thecis-βC isomers yielded similar liver VA stores to the at-βC isomer in Mongolian gerbils, and liver VA stores of the 9c- and 13c-βC groups did not differ when the doses were provided at physiological levels over time in two studies.


2014 ◽  
Vol 111 (12) ◽  
pp. 2135-2145 ◽  
Author(s):  
Alexandra Dostal ◽  
Christophe Lacroix ◽  
Van T. Pham ◽  
Michael B. Zimmermann ◽  
Christophe Del'homme ◽  
...  

The global prevalence of Fe deficiency is high and a common corrective strategy is oral Fe supplementation, which may affect the commensal gut microbiota and gastrointestinal health. The aim of the present study was to investigate the impact of different dietary Fe concentrations on the gut microbiota and gut health of rats inoculated with human faecal microbiota. Rats (8 weeks old, n 40) were divided into five (n 8 each) groups and fed diets differing only in Fe concentration during an Fe-depletion period (12 weeks) and an Fe-repletion period (4 weeks) as follows: (1) Fe-sufficient diet throughout the study period; (2) Fe-sufficient diet followed by 70 mg Fe/kg diet; (3) Fe-depleted diet throughout the study period; (4) Fe-depleted diet followed by 35 mg Fe/kg diet; (5) Fe-depleted diet followed by 70 mg Fe/kg diet. Faecal and caecal samples were analysed for gut microbiota composition (quantitative PCR and pyrosequencing) and bacterial metabolites (HPLC), and intestinal tissue samples were investigated histologically. Fe depletion did not significantly alter dominant populations of the gut microbiota and did not induce Fe-deficiency anaemia in the studied rats. Provision of the 35 mg Fe/kg diet after feeding an Fe-deficient diet significantly increased the abundance of dominant bacterial groups such as Bacteroides spp. and Clostridium cluster IV members compared with that of an Fe-deficient diet. Fe supplementation increased gut microbial butyrate concentration 6-fold compared with Fe depletion and did not affect histological colitis scores. The present results suggest that Fe supplementation enhances the concentration of beneficial gut microbiota metabolites and thus may contribute to gut health.


2013 ◽  
Vol 448-453 ◽  
pp. 4215-4218
Author(s):  
Ying Hua ◽  
Bo Song Cheng

The coal resource-based cities has now entered the depletion period due to the long uncontrolled exploitation. With the deterioration of the living environment, cities are facing the great challenges of economic restructuring. This article analyses the living environment status of coal urban in northeast of China in two aspects of the industrial building and civil construction, from environmental managing, ecological planning, industrial scaling, government functions, economic development and other several aspects to identify the factors that cause urban environmental pollution and ecological damage which affect the sound development of ecological living environment, sums strategies and controls measures which suit living environment’s sustainable development of coal resource city.


2013 ◽  
Vol 361-363 ◽  
pp. 508-513
Author(s):  
Hua Ying ◽  
Bo Song Cheng ◽  
Sun Ming ◽  
Lu Bin Dai

Coal resource cities of Heilongjiang Province had entered a depletion period as a result of long-term immoderate mining and they were facing the huge challenge of economic transformation. This paper analyses the present situation of human settlement of coal cities and then finds out the factors leading to the city environmental pollution and ecological destruction that influence human settlement. Several aspects such as environmental governance, ecological planning, industry scale, economic development and so on are discussed. The countermeasures and measures are put forward which are suitable for the sustainable development of human settlement in coal resource cities of Heilongjiang province.


2008 ◽  
Vol 5 (3) ◽  
pp. 669-678 ◽  
Author(s):  
T. Tanaka ◽  
T. F. Thingstad ◽  
T. Løvdal ◽  
H.-P. Grossart ◽  
A. Larsen ◽  
...  

Abstract. Availability of phosphate for phytoplankton and bacteria and of glucose for bacteria at different pCO2 levels were studied in a mesocosm experiment (PeECE III). Using nutrient-depleted SW Norwegian fjord waters, three different levels of pCO2 (350 μatm: 1×CO2; 700 μatm: 2×CO2; 1050 μatm: 3×CO2) were set up, and nitrate and phosphate were added at the start of the experiment in order to induce a phytoplankton bloom. Despite similar responses of total particulate P concentration and phosphate turnover time at the three different pCO2 levels, the size distribution of particulate P and 33PO4 uptake suggested that phosphate transferred to the >10 μm fraction was greater in the 3×CO2 mesocosm during the first 6–10 days when phosphate concentration was high. During the period of phosphate depletion (after Day 12), specific phosphate affinity and specific alkaline phosphatase activity (APA) suggested a P-deficiency (i.e. suboptimal phosphate supply) rather than a P-limitation for the phytoplankton and bacterial community at the three different pCO2 levels. Specific phosphate affinity and specific APA tended to be higher in the 3×CO2 than in the 2×CO2 and 1×CO2 mesocosms during the phosphate depletion period, although no statistical differences were found. Glucose turnover time was correlated significantly and negatively with bacterial abundance and production but not with the bulk DOC concentration. This suggests that even though constituting a small fraction of the bulk DOC, glucose was an important component of labile DOC for bacteria. Specific glucose affinity of bacteria behaved similarly at the three different pCO2 levels with measured specific glucose affinities being consistently much lower than the theoretical maximum predicted from the diffusion-limited model. This suggests that bacterial growth was not severely limited by the glucose availability. Hence, it seems that the lower availability of inorganic nutrients after the phytoplankton bloom reduced the bacterial capacity to consume labile DOC in the upper mixed layer of the stratified mesocosms.


2007 ◽  
Vol 4 (6) ◽  
pp. 3937-3960 ◽  
Author(s):  
T. Tanaka ◽  
T. F. Thingstad ◽  
T. Løvdal ◽  
H.-P. Grossart ◽  
A. Larsen ◽  
...  

Abstract. Availability of phosphate for phytoplankton and bacteria and of labile organic carbon for bacteria at different pCO2 levels were studied in a mesocosm experiment (PeECE III). Using nutrient-depleted SW Norwegian fjord waters, three different levels of pCO2 (350 μatm: 1×CO2; 750 μatm: 2×CO2; 1050 μatm: 3×CO2) were set up, and nitrate and phosphate were added at the start of the experiment in order to induce a phytoplankton bloom. Despite similar responses of total particulate P concentration and phosphate turnover time at the three different pCO2 levels, the size distribution of particulate P and 33PO4 uptake suggested that phosphate transferred to the >10 μm fraction was greater in the 3×CO2 mesocosm during the first 6–10 days when phosphate concentration was high. During the period of phosphate depletion (after Day 12), specific phosphate affinity and specific alkaline phosphatase activity (APA) suggested a P-deficiency (i.e. suboptimal phosphate supply) but not a P-limitation for the phytoplankton and bacterial community at the three different pCO2 levels. Although specific phosphate affinity and specific APA tended to be higher in 3×CO2 than in 2×CO2 and 1×CO2 mesocosms during the phosphate depletion period, no statistical differences were found. Responses of specific glucose affinity for bacteria were similar at the three different pCO2 levels. Measured specific glucose affinities were consistently much lower than the theoretical maximum predicted from the diffusion-limited model, suggesting that bacterial growth was not limited by the availability of labile dissolved organic carbon. These results suggest that availability of phosphate and glucose was similar at the three different pCO2 levels.


2007 ◽  
Vol 16 (1) ◽  
pp. 18-25 ◽  
Author(s):  
G. Flachowsky ◽  
F. Schöne ◽  
M. Leiterer ◽  
D. Bemmann ◽  
M. Spolders ◽  
...  

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