• 제목/요약/키워드: nutrient availability

검색결과 212건 처리시간 0.019초

삼림생태계에서의 교란과 그 역할 (Disturbance and Its Role in Forest Ecosystems)

  • 조도순
    • Journal of Plant Biology
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    • 제33권2호
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    • pp.147-150
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    • 1990
  • Different species with similar niches can coexist in the same community if disturbances prevent compeptitive exclusion of competitively inferior species. Disturbances which open up gaps are common in all kind of community. Even in virgin forests without any artificial disturbance, there exist a significant proportion of trees of early successional shade-in-tolerant species in addition to the dominant late successional shade-tolerant species. In forest ecosystems, most canopy tree species including shade-tolerant ones require one or more gaps in their life-time to reach the canopy. Because of these frequent disturbances, forests can be considered of dynamic mosaics of patches of different ages and with different species composition which are in certain stages of recovery from disturbances. Disturbances temporarily increase the availability of resources such as light, water and soil nutrient for other in dividuals through the death of one or more canopy trees.

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Nutritional Requirements and Management Strategies for Farmed Deer - Review -

  • Shin, H.T.;Hudson, R.J.;Gai, X.H.;Suttie, J.M.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권4호
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    • pp.561-573
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    • 2000
  • Knowledge concerning the nutritional requirements and nutritional problems of fanned deer is limited. Nutritional recommendations must be based on data from domestic ruminants and fanned deer. An understanding of the biology and adaptative characteristics of wild deer is essential for sensible application of sheep and cattle nutritional principles. Nutritional requirements of deer are generally separated into five categories: energy, protein, minerals, vitamins and water. Research on deer nutrition has primarily focused on energy, protein and minerals (phosphorus and calcium). Changes in the nutritional requirements that occur with gestation, lactation, breeding and antler growth should be coordinated with seasonal changes in nutrient availability from forage plants. This paper describes aspects of current knowledge of energy, protein, minerals, vitamins and water requirements. Nutritional problems of. fanned deer are described with recommendations for prevention or control. A comparison of production efficiency of deer, lamb, beef cattle and dairy cattle is included.

FEED RESOURCE AVAILABILITY AND UTILIZATION IN SMALLHOLDER PIG FARMS IN SRI LANKA

  • Ravindran, V.;Cyril, H.W.;Nadesalingam, P.;Gunawardene, D.D.
    • Asian-Australasian Journal of Animal Sciences
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    • 제8권4호
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    • pp.311-316
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    • 1995
  • Data on available feed resources, feeding practices and nutrient adequacy of rations under small farm conditions in Sri Lanka were obtained in a baseline survey involving 104 pig farms. The results showed that a wide range of non-conventional feedstuffs are used for pig feeding under typical small farm conditions and that dietary protein quality is a major factor limiting productivity. Following the survey, two on-farm trials were conducted to evaluate cheaper, alternative feeding strategies. In trial 1, a test diet was formulated using several non-conventional feedstuffs and compared with a commercial feed that is normally fed in the farms. In trial 2, the possibility of improving growth rates by amino acid supplementation was evaluated. The results demonstrated that feed costs can be considerably lowered through these packages. Some problems inherent to on-farm livestock trials are highlighted.

생물학적 축산분뇨처리시설에서 인 회수의 가능성 평가 (Feasibility of Phosphorus Recovery from Biological Livestock Wastewater Treatment Plant)

  • 안조환;김장호;민성재
    • 한국물환경학회지
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    • 제32권4호
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    • pp.343-348
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    • 2016
  • A chemical sequencing batch reactor was operated to test the feasibility of nutrient recovery from a biological livestock wastewater treatment plant. Both phosphate and ammonia could be successfully recovered as magnesium ammonium phosphate (MAP) crystals. The contents of TP and TN in the recovered MAP crystals were 26.2% and 4.0%, respectively. Zn, Cr and Ti were identified in the crystals, but the contents remained below the Korean standard for an organic fertilizer. Chemical analyses confirmed that the MAP crystals could be useful phosphate fertilizers. On the other hand, the results of physical analyses using an X-ray diffractometer and an energy dispersive X-ray spectrometer strongly suggested that crystalline materials like magnesium potassium phosphate (KMP) and hydroxyapatite (HAP) were also formed during the MAP crystallization, depending on the availability of K+ and Ca2+.

Variation of Soil Mycoflora in Decomposition of Rice Stubble from Rice-wheat Cropping System

  • Vibha, Vibha;Sinha, Asha
    • Mycobiology
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    • 제35권4호
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    • pp.191-195
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    • 2007
  • The colonization pattern and extent of decay produced in paddy stubble by soil inhabiting mycoflora were done by using nylon net bag technique. Among the three methods used for isolation of fungi, dilution plate technique recorded the highest number of fungi followed by damp chamber and direct observation method. Nutrient availability and climatic conditions (temperature, humidity and rainfall) influenced the occurrence and colonization pattern of fungi. Maximum fungal population was recorded in October ($48.99{\times}10^4/g$ dry litter) and minimum in May ($11.41{\times}10^4/g$ dry litter). Distribution of Deuteromycetous fungi was more in comparison to Zygomycetes, oomycetes and ascomycetes. In the early stage of decomposition Mucor racemosus, Rhizopus nigricans, Chaetomium globosum and Gliocladium species were found primarly whereas at later stages of decomposition preponderance of Aspergillus candidus, Torula graminis, Cladosporiun cladosporioides and Aspergillus luchuensis was recorded.

신생아에서의 포도당 대사와 저혈당증의 평가 (Glucose metabolism and evaluation of hypoglycemia in neonates)

  • 김은영
    • Clinical and Experimental Pediatrics
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    • 제50권3호
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    • pp.223-229
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    • 2007
  • The fetus is completely dependent on mother for glucose and other nutrient transfer across the placenta. At birth, when the maternal supply is discontinued, the neonate must adjust to an independent existence. The changes in the neonate's glucose homeostasis during this transition to the extrauterine environment are influenced by the mother's metabolism and intrinsic fetal and placental problems. Maturation of carbohydrate homeostasis results from a balance between substrate availability and coordination of developing hormonal, enzymatic, and neural systems. These mechanisms may not be fully developed in neonates, so the neonate is vulnerable to carbohydrate disequilibrium resulting in damage to the central nervous system. Hypoglycemia is a relatively common metabolic problem seen during newborn care. However its definition, management and long term sequalae remain controversial. Hyporglycemia occurs frequently as a transient disorder with excellent prognosis. It also may persist and recur and cause permanent neurological complications. Although the key to effective treatment of hypoglycemia is diagnostic specific, the maintenance of euglycemia is critical to the preservation of central nervous system function. This article discusses physiology of perinatal glucose homeostasis, focusing on evaluation and treatment of hypoglycemia.

石灰岩地域 소나무림에서 지렁이 Casts 와 上層土 性質의 比較 (Comparisons of Soil Properties between Earthworm Casts and Top Soil of Red Pine Forests in a Limestone Area)

  • Mun, Hyeong-Tae;Joon-Ho Kim
    • The Korean Journal of Ecology
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    • 제14권1호
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    • pp.113-117
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    • 1991
  • Comparisons of the physico-chemical properties of earthworm(Lumbricus terrestris) soil casts and top soil of red pine forests in a limestone area were carried out. The casts production durign August and September in 1990 amounted to 6∼7t/ha. The particle of top soil and casts ranged 40∼50% and 10∼20% for sand , 25∼30% and 30∼35% for silt, and 20∼25% and 55∼65% clay, respectively. Significant difference in pH value was not observed between casts and top soil. The casts had 1.4times of organic matter, 1.5times of N, 1.8times of available P, 2times of exchangeable K, 1.3times of exchangeable Ca, and 1.6times of exchangeable Mg than the top 10cm of soil did. Earthworms have altered the soil texture and increased nutrient availability through production of the soil casts in this limestone area.

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Intrinsic and Extrinsic Regulation of Hematopoiesis in Drosophila

  • Koranteng, Ferdinand;Cho, Bumsik;Shim, Jiwon
    • Molecules and Cells
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    • 제45권3호
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    • pp.101-108
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    • 2022
  • Drosophila melanogaster lymph gland, the primary site of hematopoiesis, contains myeloid-like progenitor cells that differentiate into functional hemocytes in the circulation of pupae and adults. Fly hemocytes are dynamic and plastic, and they play diverse roles in the innate immune response and wound healing. Various hematopoietic regulators in the lymph gland ensure the developmental and functional balance between progenitors and mature blood cells. In addition, systemic factors, such as nutrient availability and sensory inputs, integrate environmental variabilities to synchronize the blood development in the lymph gland with larval growth, physiology, and immunity. This review examines the intrinsic and extrinsic factors determining the progenitor states during hemocyte development in the lymph gland and provides new insights for further studies that may extend the frontier of our collective knowledge on hematopoiesis and innate immunity.

AMPK Alchemy: Therapeutic Potentials in Allergy, Aging, and Cancer

  • Ram Hari Pokhrel;Suman Acharya;Sunil Mishra;Ye Gu;Umar Manzoor;Jeon-Kyung Kim;Youngjun Park;Jae-Hoon Chang
    • Biomolecules & Therapeutics
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    • 제32권2호
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    • pp.171-182
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    • 2024
  • All cells are equipped with intricate signaling networks to meet the energy demands and respond to the nutrient availability in the body. AMP-activated protein kinase (AMPK) is among the most potent regulators of cellular energy balance. Under ATP -deprived conditions, AMPK phosphorylates substrates and affects various biological processes, such as lipid/glucose metabolism and protein synthesis. These actions further affect the cell growth, death, and functions, altering the cellular outcomes in energy-restricted environments. AMPK plays vital roles in maintaining good health. AMPK dysfunction is observed in various chronic diseases, making it a promising target for preventing and alleviating such diseases. Herein, we highlight the different AMPK functions, especially in allergy, aging, and cancer, to facilitate the development of new therapeutic approaches in the future.

Protein molecular structure, degradation and availability of canola, rapeseed and soybean meals in dairy cattle diets

  • Tian, Yujia;Zhang, Xuewei;Huang, Rongcai;Yu, Peiqiang
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권9호
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    • pp.1381-1388
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    • 2019
  • Objective: The aims of this study were to reveal the magnitude of the differences in protein structures at a cellular level as well as protein utilization and availability among soybean meal (SBM), canola meal (CM), and rapeseed meal (RSM) as feedstocks in China. Methods: Experiments were designed to compare the three different types of feedstocks in terms of: i) protein chemical profiles; ii) protein fractions partitioned according to Cornell Net Carbohydrate and Protein System; iii) protein molecular structures and protein second structures; iv) special protein compounds-amino acid (AA); v) total digestible protein and energy values; vi) in situ rumen protein degradability and intestinal digestibility. The protein second structures were measured using FT/IR molecular spectroscopy technique. A summary chemical approach in National Research Council (NRC) model was applied to analyze truly digestible protein. Results: The results showed significant differences in both protein nutritional profiles and protein structure parameters in terms of ${\alpha}-helix$, ${\beta}-sheet$ spectral intensity and their ratio, and amide I, amide II spectral intensity and their ratio among SBM, CM, and RSM. SBM had higher crude protein (CP) and AA content than CM and RSM. For dry matter (DM), SBM, and CM had a higher DM content compared with RSM (p<0.05), whereas no statistical significance was found between SBM and CM (p = 0.28). Effective degradability of CP and DM did not demonstrate significant differences among the three groups (p>0.05). Intestinal digestibility of rumen undegradable protein measured by three-step in vitro method showed that there was significant difference (p = 0.05) among SBM, CM, and RSM, which SBM was the highest and RSM was the lowest with CM in between. NRC modeling results showed that digestible CP content in SBM was significantly higher than that of CM and RSM (p<0.05). Conclusion: This study suggested that SBM and CM contained similar protein value and availability for dairy cattle, while RSM had the lowest protein quality and utilization.