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Thomas E. Fricke Arland Thornton Dilli R. Dahal 《Human ecology: an interdisciplinary journal》1990,18(3):283-313
This paper explores familial contexts of transition to a wage labor economy using ethnographic and survey data from Tamang communities at the northern edge of Nepal's Kathmandu Valley. Historically agro-pastoralist, the Tamang of this area have experienced social watersheds drawing them into ever closer relationships with Kathmandu. The earliest was their nineteenth century induction into corvée labor for national elites; more recent has been the accelerating monetization of the twentieth century. This analysis demonstrates trends and frames hypotheses about the social structuring of this latest process, testing them at the individual level with combined ethnographic and survey data from 1028 respondents. Multivariate analyses explore the effects of birth cohort, education, domestic group status, and settlement location on participation in non-family organized wage work. Substantive findings are related to the broader historical literature on household and family with special attention to varieties of subsistence to monetized transition. 相似文献
4.
Inka Brockhausen Arthur A Grey Henrianna Pang Harry Schachter Jeremy P Carver 《Glycoconjugate journal》1988,5(4):419-448
Sixteen asparagine-linked oligosaccharides ranging in size from (Man)2(GlcNAc)2 (Fuc)1 to (GlcNAc)6(Man)3(GlcNAc)2 were obtained from human 1-acid glycoprotein and fibrinogen, hen ovomucoid and ovalbumin, and bovine fetuin, fibrin and thyroglobulin by hydrazinolysis, mild acid hydrolysis and glycosidase treatment. The oligosaccharides hadN-acetylglucosamine at the reducing termini and mannose andN-acetylglucosamine residues at the non-reducing termini and were prepared for use asN-acetylglucosaminyltransferase substrates. Purification of the oligosaccharides involved gel filtration and high performance liquid chromatography on reverse phase and amine-bonded silica columns. Structures were determined by 360 MHz and 500 MHz proton nuclear magnetic resonance spectroscopy, fast atom bombardment-mass spectrometry and methylation analysis. Several of these oligosaccharides have not previously been well characterized.Abbreviations bis
bisecting GlcNAc
- DMSO
dimethylsulfoxide
- FAB
fast atom bombardment
- Fuc
l-fucose
- Gal
d-galactose
- GLC
gas-liquid chromatography
- GlcNAc or Gn
N-acetyl-d-glucosamine
- HPLC
high performance liquid chromatography
- Man or M
d-mannose
- MES
2-(N-morpholino)ethanesulfonate
- MS
mass spectrometry
- NMR
nuclear magnetic resonance
- PIPES
piperazine-N,N-bis(2-ethane sulfonic acid)
the nomenclature of the oligosaccharides is shown in Table 1. 相似文献
5.
Hans Fricke Karen Hissmann Jürgen Schauer Olaf Reinicke Lutz Kasang Raphael Plante 《Environmental Biology of Fishes》1991,32(1-4):287-300
Synopsis In 1987 and 1989 coelacanths were observed for the first time in their natural habitat with the help of submersibles. Coelacanths were found between 150–253 m depth, their preferential depth seems to be around 200 m; the water temperature ranged between 16.5–22.8° C. During the day coelacanths aggregate in small non-aggressive groups in sheltered lava-caves. Caves might be a limiting factor for distribution. At night they leave the caves for hunting by drifting singly along the steep lava slopes. They migrate between different caves located within a large home range covering more than 8 km coastline. Coelacanths are site-attached, some for a period of at least 2 years. Our own observations and earlier catch records show that only the west coast of Grand Comoro is a suitable coelacanth habitat with more structural complexity and prey fish abundance than other coastlines of the island. From our survey we estimated a total coelacanth population off Grand Comoro to be 150–210 individuals; a saturated population would be 370–510 individuals. This small relict population seems to be stable. International protection of coelacanths against commercial interests is needed 相似文献
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Folkert Reck Ernst Meinjohanns Matthias Springer Roland Wilkens Johannes A. L. M. Van Dorst Hans Paulsen Gabriele Möller Inka Brockhausen Harry Schachter 《Glycoconjugate journal》1994,11(3):210-216
UDP-GlcNAc: Man1-6R (1-2)-N-acetylglucosaminyltransferase II (GlcNAc-T II; EC 2.4.1.143) is a key enzyme in the synthesis of complexN-glycans. We have tested a series of synthetic analogues of the substrate Man1-6(GlcNAc1-2Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T II. The enzyme attachesN-acetylglucosamine in 1-2 linkage to the 2-OH of the Man1-6 residue. The 2-deoxy analogue is a competitive inhibitor (K
i=0.13mm). The 2-O-methyl compound does not bind to the enzyme presumably due to steric hindrance. The 3-, 4- and 6-OH groups are not essential for binding or catalysis since the 3-, 4- and 6-deoxy and -O-methyl derivatives are all good substrates. Increasing the size of the substituent at the 3-position to pentyl and substituted pentyl groups causes competitive inhibition (K
i=1.0–2.5mm). We have taken advantage of this effect to synthesize two potentially irreversible GlcNAc-T II inhibitors containing a photolabile 3-O-(4,4-azo)pentyl group and a 3-O-(5-iodoacetamido)pentyl group respectively. The data indicate that none of the hydroxyls of the Man1-6 residue are essential for binding although the 2- and 3-OH face the catalytic site of the enzyme. The 4-OH group of the Man-O-octyl residue is not essential for binding or catalysis since the 4-deoxy derivative is a good substrate; the 4-O-methyl derivative does not bind. This contrasts with GlcNAc-T I which cannot bind to the 4-deoxy-Man- substrate analogue. The data are compatible with our previous observations that a bisectingN-acetylglucosamine at the 4-OH position prevents both GlcNAc-T I and GlcNAc-T II catalysis. However, in the case of GlcNAc-T II, the bisectingN-acetylglucosamine prevents binding due to steric hindrance rather than to removal of an essential OH group. The 3-OH of the Man1-3 is an essential group for GlcNAc-T II since the 3-deoxy derivative does not bind to the enzyme. The trisaccharide GlcNAc1-2Man1-3Man-O-octyl is a good inhibitor (K
i=0.9mm). The above data together with previous studies indicate that binding of the GlcNAc1-2Man1-3Man- arm of the branched substrate to the enzyme is essential for catalysis.
Abbreviations: GlcNAc-T I, UDP-GlcNAc:Man1-3R (1-2)-N-acetylglucosaminyltransferase I (EC 2.4.1.101); GlcNAc-T II, UDP-GlcNAc:Man1-6R (1-2)-N-acetylglucosaminyltransferase II (EC 2.4.1.143); MES, 2-(N-morpholino)ethane sulfonic acid monohydrate. 相似文献
8.
Because cow ovaries do not contain a dominant follicle before Day 3 of the estrous cycle, we hypothesized that gonadotropin treatment early in the estrous cycle would induce growth of multiple follicles and could be used to induce superovulation. In Experiment 1, when 16 cows were treated with FSH-P beginning on Day 2 of the estrous cycle and were slaughtered on Day 5, all cows responded to gonadotropin treatment by exhibiting a large number ( approximately 19) of estrogenactive follicles >/= 6 mm. In Experiment 2, in response to FSH-P treatment from Day 2 to Day 7, and fenprostalene treatment on Day 6, 11 of 15 cows exhibited estrus and had a mean ovulation rate of 23.7 +/- 1.5. In Experiment 3, an FSH-P treatment regimen identical to that used in Experiment 2 was administered to cows beginning either on Day 2 (Day-2 cows; n=14) or Day 10 (Day-10 cows; n=11) of the estrous cycle. Twelve of 14 Day-2 cows and all Day-10 cows exhibited estrus after fenprostalene treatment. Day-2 cows exhibited 34.3 +/- 7.0 ovulations, which was less (P < 0.05) than that exhibited by Day-10 cows (48.3 +/- 4.4). However, the proportion of embryos recovered per corpus luteum was about 2-fold greater (P < 0.05) for Day-2 cows than for Day-10 cows (0.49 +/- 0.08 vs 0.27 +/- 0.06). These data indicate that beginning gonadotropin treatment early in the estrous cycle, when a dominant follicle is not present, provides an efficacious means to induce growth of multiple follicles and superovulation in cows. However, when FSH was administered for 6 d, beginning the treatment on Day 10 also resulted in a consistent and efficacious response. 相似文献
9.
Cells of the Upper and Lower Epidermis of Barley (Hordeum vulgare L.) Leaves Exhibit Distinct Patterns of Vacuolar Solutes 总被引:3,自引:0,他引:3 下载免费PDF全文
Vacuolar saps were extracted from individual, anatomically uniform cells of the upper (adaxial) and lower (abaxial) epidermis of the third leaf of barley (Hordeum vulgare L.) using a modified pressure probe. Saps (volume 80-200 pL) were sampled at various times between 3 d before and 7 d after full-leaf expansion and were analyzed for their osmolality and their concentrations of NO3-, malate, CI-, K+, and Ca2+. The osmolalities of upper and lower epidermis both increased with time but were similar to each other. In young leaves, K+ and Ca2+ were evenly distributed between the two epidermal layers, but as the leaf aged, the upper epidermis accumulated high (40-100 mM) Ca2+, whereas cells of the lower epidermis accumulated K+ instead. Nitrate concentration was 100 to 150 mM higher in the upper than in the lower epidermis, whereas CI- was 50 to 120 mM higher in the lower epidermis. These differences did not depend on the leaf developmental stage. The uneven distribution of epidermal NO3- and CI- was maintainedover a wide range of epidermal sap concentrations of these ions and was not affected by NO3- or CI- starvation or by an increase in the light intensity from 120 to 400 [mu]mol m-2 s-1. However, the latter did cause a decrease in epidermal NO3- and the appearance and accumulation of epidermal malate, particularly in the upper epidermis. The physiological implications of the results for solute storage in leaves and for the pathways of ion distribution to the epidermis are discussed. 相似文献
10.
Callionymus leucopoecilus, a new species of dragonet from the Yellow Sea, is described and illustrated. The new species is characterized by 4 spines
in the first dorsal fin, 9 rays each in the second dorsal and anal fins, ii, 5, ii principal caudal fin rays, a preopercular
spine formula of
相似文献