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21.
Global hydrological cycles and world water resources   总被引:7,自引:0,他引:7  
Oki T  Kanae S 《Science (New York, N.Y.)》2006,313(5790):1068-1072
Water is a naturally circulating resource that is constantly recharged. Therefore, even though the stocks of water in natural and artificial reservoirs are helpful to increase the available water resources for human society, the flow of water should be the main focus in water resources assessments. The climate system puts an upper limit on the circulation rate of available renewable freshwater resources (RFWR). Although current global withdrawals are well below the upper limit, more than two billion people live in highly water-stressed areas because of the uneven distribution of RFWR in time and space. Climate change is expected to accelerate water cycles and thereby increase the available RFWR. This would slow down the increase of people living under water stress; however, changes in seasonal patterns and increasing probability of extreme events may offset this effect. Reducing current vulnerability will be the first step to prepare for such anticipated changes.  相似文献   
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The aim of the current study was to examine the effects of clenbuterol injection into newly hatched chicks on both the abdominal fat pad tissue weight and the skeletal muscle weight during subsequent growth. Twenty‐seven 1‐day‐old chicks were divided into two groups, receiving either a single intraperitoneal (i.p.) injection of clenbuterol (0.1 mg/kg body weight) or phosphate‐buffered saline (PBS). Body weight gain, feed intake and feed conversion ratio were not affected by clenbuterol injection during the 5‐week experimental period, while the abdominal fat pad tissue weight of the clenbuterol‐injected chicks was lower than that of the control chicks at 5 weeks post‐injection. Plasma non‐esterified fatty acid concentrations were significantly increased in the clenbuterol‐injected chicks, while plasma triacylglycerol concentrations did not differ. Additionally, the enzymatic activity of fatty acid synthase was lower in the liver of the clenbuterol‐injected chicks. Conversely, the skeletal muscle weights were not affected by clenbuterol injection. These results suggest that a single clenbuterol injection into 1‐day‐old chicks decreases the abdominal fat pad tissue weight, but may not affect skeletal muscle weights during growth. © 2015 Japanese Society of Animal Science  相似文献   
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To eliminate pathogens, the initiation of an appropriate immune response is critical. When the gastrointestinal nematode, Heligmosomoides polygyrus (Hp), invades the small intestine, a type-2 cytokine response is initiated; however, this response is not sufficient to clear the infection, and chronic infection can ensue. In this study, the host defense against Hp was investigated in mice with a focus on the role of CD4+ T cells. To this end, tissues from the small intestine and mesenteric lymph node (MLN) were collected every day from just after infection until Day 5 because many previous studies have described the later stages of infection from Day 8 to Day 12, during which Hp returns to the lumen and Th2 cytokine expression reaches its peak. In this study, we focused on investigating the initiation of the type-2 immune response. Our results indicated that the larvae encysted by Day 3. Increased type-2 cytokine gene expression started in the small intestine before Day 2 and increased again on Day 5. Interferon (IFN) γ increased significantly on the second day. Flow cytometry and gene expression analysis of MLN cells revealed that CD4+ T cells were not activated until Day 4. These results suggested that innate immune cells in submucosa are activated immediately after infection, but CD4+ T cells accumulate in the cyst zone later. In addition, IFNγ may have an important role in converting type-2 cytokine-producing cells from innate cells to CD4+ T cells.  相似文献   
26.
Dogs are well adapted to cold climates and they can stand, walk and run on snow and ice for long periods of time. In contrast to the body trunk, which has, dense fur, the paws are more exposed to the cold due to the lack of fur insulation. The extremities have a high surface area-to-volume ratio, so they lose heat very easily. We offer anatomical evidence for a heat-conserving structure associated with dog footpad vasculature. Methylmethacrylate vascular corrosion casts for scanning electron microscopy, Indian ink-injected whole-mount and histological specimens were each prepared, in a series of 16 limbs from four adult dogs. Vascular casts and Indian ink studies showed that abundant venules were arranged around the arteries supplying the pad surface and formed a vein-artery-vein triad, with the peri-arterial venous network intimately related to the arteries. In addition, numerous arteriovenous anastomoses and well-developed venous plexuses were found throughout the dermal vasculature. The triad forms a counter-current heat exchanger. When the footpad is exposed to a cold environment, the counter-current heat exchanger serves to prevent heat loss by recirculating heat back to the body core. Furthermore, the arteriovenous anastomoses shift blood flow, draining blood to the skin surface, and the venous plexuses retain warm blood in the pad surface. Hence, the appropriate temperature for the footpad can be maintained in cold environments.  相似文献   
27.
Polyphenolic compounds from chestnut astringent skin (CAS) were purified by dialysis, using Diaion HP-20 and Sephadex LH-20 columns. During purification, specific α-amylase inhibitory activities were increased about 3.4-fold, and the 50% inhibition value was 5.71 μg/mL in the Sephadex LH-20 fraction (SE-fraction). The SE-fraction contained about 67% of the total polyphenols, 57.3% of the flavanol-type tannins, and 51.3% of the procyanidins. Strong antioxidant activity was observed in the SE-fraction. Oral administration of the SE-fraction in rats fed corn starch significantly suppressed an increase in blood glucose levels. The SE-fraction contained gallic acid and ellagic acid. The MALDI-TOF spectrum showed a peak series exhibiting a mass increment of 288 Da, reflecting the variation in the number of catechin/epicatechin units. Our results suggest CAS contains polyphenols with strong α-amylase inhibitory activity. The data also suggest CAS polyphenols might be oligomeric proanthocyanidins with gallic acid and ellagic acid.  相似文献   
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An on‐farm trial was carried out to improve the current low‐income farmers’ diet and to assess farm conditions that could accept the new ingredients using locally available feed resources in the Mekong Delta region. A total of 42 local Large White‐type pigs, comprising 20 barrows and 22 gilts with initial‐to‐final mean live weight of 34.2–93.0 kg, were used. The trial was designed as a 3 × 3 factorial with three agricultural gross income levels of seven farm households and three dietary treatments. The annual income levels were high income (HI; $US2355 on average), medium income (MI; $US1439) and low income (LI; $US1116). The three types of diets were farmers’ common diet (FCD), rice‐based diet (RBD) and water‐hyacinth (Eichhornia crassipes)‐supplemented diet (WHD). A total of 12 pigs, consisting of two barrow–gilt couples in each diet treatment, were slaughtered at the end of the trial. The daily weight gain (DG) was higher and the feed conversion ratio (FCR) was lower in the MI and LI pigs than in the HI pigs over the entire fattening period (P < 0.01). No significant effect of the diet treatments was observed on the aforementioned two parameters, but the backfat thickness was least in WHD (16.8 mm) and next least in RBD (17.1 mm), compared with that of FCD pigs (19.4 mm; P < 0.05). The iodine values of RBD and WHD backfat were lower (P < 0.001) than those of FCD backfat. The cost performance, defined as feed cost per kg weight gain, was lowest for MI, intermediate for LI and highest for HI levels (P < 0.05). Therefore, the benefit was highest at the MI level and lowest at the HI level (P < 0.05). In contrast, cost performance of the diet treatments tended to be higher in FCD, and lower in RBD and WHD (P < 0.1). Then, the benefit tended to be higher in RBD and WHD than in the FCD diet (P < 0.1). Overall, these results suggest that the RBD and WHD diets be recommended especially to households with medium and low agricultural incomes.  相似文献   
29.
The starch and protein properties of rice grain are important factors for sake brewing and these properties are reported to be influenced by temperatures during grain ripening. Amylose content, nitrogen content, protein composition, pasting properties measured by a Rapid Visco Analyser (RVA), and their relationship to temperatures during ripening were investigated in a rice cultivar, Yamadanishiki, which was grown under various conditions in the same experimental field. The average temperature after heading was significantly correlated with amylose content and RVA properties, but not with nitrogen content. Under high temperatures during ripening, a decrease in prolamin, which accumulated in type I protein body (PB-I), and an increase in glutelin, which deposits in type II PB (PB-II), were recognized. The ratio of PB-II/PB-I and RVA pasting temperatures were distinctly increased as the temperature became higher. High temperatures during grain ripening would lead to difficulties in digesting steamed rice grains by Aspergillus oryzae, together with ease in digesting rice protein. The average temperature of 11–20 days after heading showed a higher correlation coefficient than that of 1–10 or 21–30 days, implying that temperatures during the middle stage of grain development would be important in determining the rice component that relates to brewing properties.  相似文献   
30.
ABSTRACT:   Samples of river waters containing high concentrations of zinc and other heavy metals but low concentrations of other anthropogenic contaminants were collected to investigate the relationship between toxicity of heavy metals and naturally present organic matters or hardness, as well as the effects of heavy metals on aquatic organisms. Acute toxicity tests were conducted for the water samples using Daphnia magna and medaka Oryzias latipes . Almost all the D. magna died in river waters containing high concentrations of zinc, but O. latipes in the same waters were hardly affected. Since the test organisms were not only exposed to zinc but also other heavy metals in the river waters, we examined the toxicity using toxic units composed of zinc, copper, lead, and cadmium. The results of a bioassay with the river waters showed that the mortality of D. magna did not depend solely on the total number of toxic units of heavy metals. The organic matters and the hardness of the river waters could decrease the acute toxicity of zinc and other heavy metals to D. magna .  相似文献   
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