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21.
A survey was carried out among 40 ornamental plant cultivators in three major cities in Nigeria, Lagos, Ibadan, and Abeokuta on their cultivation practices using compost. The newly emerging industry is in need of a large supply of compost. No chemical fertilizers are currently being used. Over 30 varieties of ornamental plants are cultivated throughout the year.

Some of the identified constraints seemed to be water shortage, sufficient capital, availability of farm inputs, low demand in smaller towns and villages, pilfering and insect damage, and nonavailability of land, high cost of labor and transportation. The respondents expressed their need for proper training and guidance on the preparation and use of their own composts and control of pests and weeds.  相似文献   
22.
This study aims to determine leaf litter preference, consumption rate, growth rate, food conversion efficiency, and quality of fecal pellets of two endemic pill millipedes (Arthrosphaera dalyi and Arthrosphaera davisoni) of the Western Ghats of India by laboratory microcosm experiments. Among seven combinations of three plantation leaf litters offered in 4-day trial, top three preferred combinations were selected for 4-week trial. In 4-week trial, preference of mixed litter diet was higher than single litter diet, which resulted in enhanced growth as well as food conversion efficiency of millipedes. Among Hopea , Pongamia , and Areca litters, A. dalyi preferred Hopea + Pongamia, and its consumption was significantly correlated with contents of organic carbon (P < 0.05; r = –0.97) and nitrogen (P < 0.01; r = 0.99), while growth rate with phosphorus content (P < 0.05; r = 0.97) and food conversion efficiency with contents of organic carbon (P < 0.05; r = 0.98) and calcium (P < 0.01; r = –0.99). Among Areca , Elettaria , and Coffea litters, Areca + Elettaria+ Coffea was most preferred by A. davisoni, which was significantly correlated with organic carbon content (P < 0.05; r = 0.98) and food conversion efficiency with calcium content (P < 0.0001; r = 0.99). The food conversion efficiency, however, was the highest in millipedes fed with Areca  +  Elettaria. The present study demonstrated increased nitrogen and phosphorus contents and decreased phenolic content and C/N ratio in fecal pellets of pill millipedes fed with plantation litter, and thus, these millipedes play an important role in leaf litter mineralization and soil enrichment in plantations Western Ghats.  相似文献   
23.
24.
Sequencing and analysis of Neanderthal genomic DNA   总被引:1,自引:0,他引:1  
Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we must make inferences about their biology, behavior, and relationship to ourselves. Here, we describe the characterization of these extinct hominids from a new perspective, based on the development of a Neanderthal metagenomic library and its high-throughput sequencing and analysis. Several lines of evidence indicate that the 65,250 base pairs of hominid sequence so far identified in the library are of Neanderthal origin, the strongest being the ascertainment of sequence identities between Neanderthal and chimpanzee at sites where the human genomic sequence is different. These results enabled us to calculate the human-Neanderthal divergence time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor approximately 706,000 years ago, and that the human and Neanderthal ancestral populations split approximately 370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.  相似文献   
25.
The objectives of this study are: (1) Evaluate the capacity of Indian mustard (Brassica juncea) for uptake and accumulation of Cs and Sr natural isotopes. (2) Identify foliar structural and other physiological changes (biomass, relative water content etc.) resulted from the accumulation of these two elements. (3) Monitor the Cs and Sr uptake and bioaccumulation process by spectral reflectance. Potted Indian mustard plants were exposed to different concentrations of Cs (50 and 600 ppm) and Sr (50 and 300 ppm) natural isotopes in solution form for 23 days. Bioaccumulation of Cs and Sr were found in the order of leaves > stems > roots for both Cs- and Sr-treated plants. The highest leaf and root Sr accumulations are observed to be 2,708, and 1,194 mg kg?1, respectively; and the highest leaf and root Cs accumulations are 12,251, and 6,794 mg kg?1, respectively. High translocation efficiency for both elements is documented by shoot/root concentration ratios greater than one. Biomass decreases were observed for plants treated with higher concentration of Cs or Sr. Cs accumulation affected the pigment concentration and internal structure of the leaf and the spectral characteristics of plants. Within the applied concentration range, Sr accumulation resulted in no significant changes in relative water content (RWC), leaf structural and spectral characteristics of mustard plants. Cs shoot concentration showed significant negative correlation with relative water content (RWC; r = ?0.88*) and normalized difference vegetative index (NDVI) value (r = ?0.68*) of plant shoots. The canopy spectral reflectance and NDVI analysis clearly revealed (p < 0.05) the stress caused by Cs accumulation.  相似文献   
26.
The heavy metal contents of some solid wastes produced in residential areas, a market, a cafeteria and the composts in lbadan, Nigeria, were measured. The solid wastes produced in low density areas with higher per capita income showed higher levels of heavy metals. The cafeteria waste showed low levels of some of these metals. The significance of the heavy metal status on Nigerian environment is discussed.  相似文献   
27.
Thirteen essential oils recovered by steam distillation from Indian herbs were analyzed for their chemical compositions using GC and GCMS. The antifungal activity against plant and Food mold rot were examined in vitro using poison food technique. The essential oil from cymbopogan exhibited control over all the plant and food mold rot tested. The bioactive compound in the oil and its minimum inhibitory concentration were determined using TLC bioautography.  相似文献   
28.
Arsenic (As) is a known carcinogen and naturally occurring semi-metal in soils and in the Earth''s crust. Contamination of soils and water with As poses a serious threat to millions of people worldwide due to its health hazards and toxicological properties. Hence, devising novel and efficient methods for remediation of contaminated areas has attracted a great deal of interest across the globe. In this study, we investigated the usefulness of synthetic birnessite, goethite, hexadecylpyridinium chloride-modified montmorillonite (HDPC-M), hexadecylpyridinium bromide-modified zeolite (HDPB-Z), and lanthanum (La)-doped magnetic biochar produced from eucalyptus bark (La-Euchar) as adsorbents at 10% dosage for As stabilization in a soil spiked with 1 000 mg kg-1 As. The effectiveness of the above adsorbents in As immobilization in soil was assessed using single-step extractions with 2 mol L-1 HNO3 and deionized water, the simplified bioaccessibility extraction test (SBET) method, and sequential extraction with the modified Community Bureau of Reference (BCR) method. Application of the adsorbents shifted the exchangeable fraction of As to more recalcitrant fractions and dramatically reduced the exchangeable fraction by 6%-99% and the extractable amounts with HNO3, deionized water, and SBET method by 30%-92%, 17%-95%, and 12%-90%, respectively, compared to the unamended control. The immobilizing effects of adsorbents on As decreased in the sequence of birnessite > La-Euchar > goethite > HDPB-Z > HDPC-M. Birnessite exhibited great affinity for As and drastically reduced As extractability by more than 90% in all single extractions. The results revealed that HDPC-M, HDPB-Z, La-Euchar, birnessite, and goethite are promising immobilizing agents for in situ stabilization of As in terrestrial environments.  相似文献   
29.
Study was conducted to find out the comparative susceptibility of fingerlings of seven species of carps (Labeo fimbriatus, L. rohita, L. calbasu, Catla catla, Ctenopharyngodon idella, Cyprinus carpio and Hypophthamichthys molitrix) grown under both mono and polyculture to Lernaea cyprinacea infection. Under monoculture, C. carpio, L. rohita and L. calbasu, did not acquire Lernaea infection and were thus considered resistant, whereas C. idella, H. molitrix, C. catla and L. fimbriatus were susceptible. Even challenge with higher infective doses of copepodids under monoculture did not result in infection in the resistant fish species. The resistance of L. rohita and C. carpio to Lernaea infection under monoculture was not sustained when these two fish species were maintained in polyculture along with susceptible fish species. Labeo calbasu, even under polyculture, however, did not acquire Lernaea infection indicating that this fish species is the most resistant and least preferred host for this parasite. Similarly, C. carpio, L. rohita and L. calbasu when grown together in polyculture and exposed to a higher infective dose (120 copepodids/fish) also did not develop the infection. The possible reasons for differences in susceptibility shown by these carp species in monoculture and the loss of resistance by rohu and common carp while in polyculture with susceptible species are discussed. The ability of resistant fish species to prevent establishment of anchor worms on them under monoculture can be utilized to control this parasitic infection commonly encountered in culture ponds.  相似文献   
30.
Although serologic data indicate horses in N. America are exposed to a variety of leptospiral serovars, abortion is almost always associated with Leptospira interrogans serovar Pomona type kennewicki. A variety of wildlife including raccoons, white tailed deer, striped skunks, opossums, and red and grey foxes have been shown to host serovar Pomona and have therefore been suspect as sources of infection for pregnant mares. The aim of the present study was to examine genetic diversity in serovar Pomona type kennewicki in wildlife and in aborting mares. Our approach utilized PCR that targeted tandem repeats at the VNTR - 4 locus and a 1235 bp 5'-sequence of the lk73.5 (sph2) and adjacent upstream sequence unique to serovar Pomona. All isolates/specimens of equine origin in 1992 and 2008 yielded amplicons of 1235 and 595 bp, whereas 14 isolates/specimens from wildlife yielding a 1235 bp amplicon characteristic of serovar Pomona produced amplicons of 1300, 550 bp (3), 1300 bp (10), or 595 bp (6) with the VNTR - 4 primer set. Wildlife therefore hosted at least three different genetic variants of type kennewicki including the genetic variant that predominated in aborting mares. The data are consistent with other studies indicating specific genetic variants of type kennewicki show a strong tendency to be associated with a specific host. Levels of antibody in wildlife sera reactive with rLk73.5, rLig130 and sonicate of type kennewicki were poorly correlated with PCR data, although rLk73.5 was superior to rLig130 in detection of antibody responses. PCR is therefore a more reliable tool for studies of wildlife reservoirs of Leptospira sp. than serologic surveillance that targets host induced proteins or LPS-rich sonicate.  相似文献   
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