Ridge Plots Research Articles

Analysis of weighted gene co-expression networks and clinical validation identify hub genes and immune cell infiltration in the endometrial cells of patients with recurrent implantation failure.

About 10% of individuals undergoing in vitro fertilization encounter recurrent implantation failure (RIF), which represents a worldwide social and economic concern. Nevertheless, the critical genes and genetic mechanisms underlying RIF are largely unknown. We first obtained three comprehensive microarray datasets "GSE58144, GSE103465 and GSE111974". The differentially expressed genes (DEGs) evaluation, enrichment analysis, as well as efficient weighted gene co-expression network analysis (WGCNA), were employed for distinguishing RIF-linked hub genes, which were tested by RT-qPCR in our 30 independent samples. Next, we studied the topography of infiltration of 22 immune cell subpopulations and the association between hub genes and immune cells in RIF using the CIBERSORT algorithm. Finally, a novel ridge plot was utilized to exhibit the potential function of core genes. The enrichment of GO/KEGG pathways reveals that Herpes simplex virus 1 infection and Salmonella infection may have an important role in RIF. After WGCNA, the intersected genes with the previous DEGs were obtained using both variance and association. Notably, the subsequent nine hub genes were finally selected: ACTL6A, BECN1, SNRPD1, POLR1B, GSK3B, PPP2CA, RBBP7, PLK4, and RFC4, based on the PPI network and three different algorithms, whose expression patterns were also verified by RT-qPCR. With in-depth analysis, we speculated that key genes mentioned above might be involved in the RIF through disturbing endometrial microflora homeostasis, impairing autophagy, and inhibiting the proliferation of endometrium. Furthermore, the current study revealed the aberrant immune infiltration patterns and emphasized that uterine NK cells (uNK) and CD4+ T cells were substantially altered in RIF endometrium. Finally, the ridge plot displayed a clear and crucial association between hub genes and other genes and key pathways. We first utilized WGCNA to identify the most potential nine hub genes which might be associated with RIF. Meanwhile, this study offers insights into the landscape of immune infiltration status to reveal the underlying immune pathogenesis of RIF. This may be a direction for the next study of RIF etiology. Further studies would be required to investigate the involved mechanisms.

Dynamic thresholding and tissue dissociation optimization for CITE-seq identifies differential surface protein abundance in metastatic melanoma

Multi-omics profiling by CITE-seq bridges the RNA-protein gap in single-cell analysis but has been largely applied to liquid biopsies. Applying CITE-seq to clinically relevant solid biopsies to characterize healthy tissue and the tumor microenvironment is an essential next step in single-cell translational studies. In this study, gating of cell populations based on their transcriptome signatures for use in cell type-specific ridge plots allowed identification of positive antibody signals and setting of manual thresholds. Next, we compare five skin dissociation protocols by taking into account dissociation efficiency, captured cell type heterogeneity and recovered surface proteome. To assess the effect of enzymatic digestion on transcriptome and epitope expression in immune cell populations, we analyze peripheral blood mononuclear cells (PBMCs) with and without dissociation. To further assess the RNA-protein gap, RNA-protein we perform codetection and correlation analyses on thresholded protein values. Finally, in a proof-of-concept study, using protein abundance analysis on selected surface markers in a cohort of healthy skin, primary, and metastatic melanoma we identify CD56 surface marker expression on metastatic melanoma cells, which was further confirmed by multiplex immunohistochemistry. This work provides practical guidelines for processing and analysis of clinically relevant solid tissue biopsies for biomarker discovery.

The role of fluvial landforms as a driver of vegetation variation on a floodplain in southern Thailand

Floodplain vegetation is rare in southern Thailand due to the generally steep gradient through which major rivers flow and high pressure of land use. This study aims to increase the understanding of factors and processes that govern vegetation variation and diversity in a floodplain to provide information for conservation and management of this threatened and rare ecosystem. A total of 20 plots, each 625 m2, were laid on three broad categories of fluvial landforms to collect data on the number of tree species (woody plants with diameter at breast height (DBH) ≥ 5 cm), soil variables, flooding, history of land use and distance to the inner curve of the channel in Nong thung thong Non-Hunting Area, Thailand. Three 4 m2 subplots were nested within each 625 m2 plot to estimate shrub composition and coverage. The alpha and beta diversity of the tree species in each fluvial landform were calculated. The relationships between vegetation data and environmental factors were explored through transformation-based Redundancy Analysis (tb-RDA) and univariate analyses. Beta diversity between abandoned channel and ridge plots, and between ridge and shallow depression plots was higher than the dissimilarities within each fluvial landform, and the balanced variation in abundance contributed to the major part of the dissimilarities. These results indicate different tolerance ranges or competitive ability of species between these fluvial landforms. Results from the tb-RDA showed that tree species composition varied with fluvial landforms and soil calcium content. Median of flooding was associated with fluvial landforms. In addition, soil calcium content could be controlled by fluvial landform because clay and calcium were correlated, and both were associated with fluvial landforms. These results suggest that variation in fluvial landforms causes variation in flooding duration, edaphic factors, vegetation variation, and ultimately, the biodiversity in this floodplain.

CellCall: integrating paired ligand-receptor and transcription factor activities for cell-cell communication.

With the dramatic development of single-cell RNA sequencing (scRNA-seq) technologies, the systematic decoding of cell-cell communication has received great research interest. To date, several in-silico methods have been developed, but most of them lack the ability to predict the communication pathways connecting the insides and outsides of cells. Here, we developed CellCall, a toolkit to infer inter- and intracellular communication pathways by integrating paired ligand-receptor and transcription factor (TF) activity. Moreover, CellCall uses an embedded pathway activity analysis method to identify the significantly activated pathways involved in intercellular crosstalk between certain cell types. Additionally, CellCall offers a rich suite of visualization options (Circos plot, Sankey plot, bubble plot, ridge plot, etc.) to present the analysis results. Case studies on scRNA-seq datasets of human testicular cells and the tumor immune microenvironment demonstrated the reliable and unique functionality of CellCall in intercellular communication analysis and internal TF activity exploration, which were further validated experimentally. Comparative analysis of CellCall and other tools indicated that CellCall was more accurate and offered more functions. In summary, CellCall provides a sophisticated and practical tool allowing researchers to decipher intercellular communication and related internal regulatory signals based on scRNA-seq data. CellCall is freely available at https://github.com/ShellyCoder/cellcall.

Ridge–mulch tillage and rotation with broad bean affect soil microbial community, diversity and crop yield in a long‐term potato continuous cropping field

AbstractSoil microbial disorder caused by continuous cropping of potato is a major challenge in the semi‐arid region of northwest China. Crop rotation can enhance crop productivity and increase soil microbial diversity. However, the functional significance of changes in soil microbial communities in different ridge‐mulching patterns of potato continuous cropping soil is poorly understood. In view of this, a study was conducted in a 5‐year potato field, to determine the effect of three different tillage practices (nonfilm‐mulched flat plot‐CK, half‐mulched ridge cropping‐T1 and fully mulched ridge cropping‐T2) and two cropping systems (potato‐potato‐C and potato/broad bean‐R) on changes in the microbial community of the soil. The soil microbial community and diversity were examined using the high‐throughput sequencing methods. The dominant bacteria phylum found in the soil was Proteobacteria. The relative abundance of Proteobacteria in fully mulched ridge plots was greater than in half‐mulched ridge and nonfilm‐mulched flat plot. The dominant bacteria genus, Arthrobacter and Planctomyces, were found in the potato–broad bean rotation system, whereas Streptomyces, Steroidobacter and Lysobacter were foremost in the plots under continuous cropping of potato. The dominant phylum of fungi was Ascomycota, and the ratio was increased by film mulching under the continuous cropping system. The relative abundances of dominant genus Monographella, Humicola and Fusarium in the continuous cropping system were higher than that of the rotation system, while Mortierella and Acremonium were dominant in the rotation plots. Moreover, the relative abundance of Humicola and Mortierella was higher in fully mulched ridge plots, while Monographella and Acremonium were higher in the nonfilm‐mulched flat plots. Ridge–mulch tillage and rotation with broad bean could change the composition of soil microbial phylum and genus level, and ridge–mulch tillage may also effect on soil microbial diversity to some extent. Besides, the yields of potato and broad bean under mulched plots were enhanced by 58.03%–73.47% and 70.37%–80.19%, respectively. The yields were greater under fully mulched ridge plots.

T134. Quantifying dynamical interactions between neural assemblies

Introduction There is accumulating evidence that brain function is strongly dependent on dynamic interactions between neural assemblies. Several methods, based on synchronization measures, are used to quantify functional connectivity between neural networks. However, despite the dynamic nature of neuronal interactions, functional connectivity is typically expressed as a mean value during the period of observation. In the present work, we characterize and quantify the spatiotemporal dynamics of these interactions using common instantaneous frequencies between different recording positions. We explore this approach in two conditions: wakefulness and generalized anesthesia. Methods We used 19-channel EEGs from patients who underwent a carotid endarterectomy during general anesthesia with propofol. Pre-operative 20 min EEGs were also available. All recordings were obtained as part of our routine care. All EEGs were recorded with Ag/AgCl electrodes with a sampling frequency of 250 Hz. EEGs were decomposed in the time-frequency plane by a short time Fourier transform. Subsequently, we used the ridge transform to subtract instantaneous frequencies from the local maxima in the time-frequency plane. The resulting ridge plots allow analysis of common instantaneous frequencies between different oscillators. We now define a link rate (LR) and a link duration (LD) for quantifying the frequency and duration of interactions, respectively. We illustrate this approach for different frequency bands (delta, theta, alpha and beta), using the EEG recordings during the eyes closed wake state and general anesthesia. Results EEGs from 21 patients were used. Link rates in the theta, alpha and beta band were significantly higher during anesthesia than during wakefulness (3.65–5.34 Hz during anesthesia, 3.51–4.55 Hz during wakefulness, p ≪ 0.05), while the link rates in the delta band were significantly lower during anesthesia (2.49 Hz during anesthesia, 2.96 Hz during wakefulness, p ≪ 0.05). The link durations in the delta and beta band were significantly shorter during anesthesia (158–124 ms during anesthesia, 168–129 ms during wakefulness, p ≪ 0.05), while those in the theta and alpha band were significantly higher (151–169 ms during anesthesia, 149–160 ms during wakefulness, p ≪ 0.05). Conclusion We present a method to characterize dynamic interactions between neural networks in the brain. A next step is to include phase information to limit volume conduction effects. Despite this limitation, we further show that link durations in most frequency bands decrease during anesthesia, supporting the notion that in this condition ‘neural integration’ is reduced.

고추재배 포장 라이시메타를 이용한 fluazinam의 유출 평가

The field lysimeter study was undertaken to investigate influence of agricultural practice and topography on runoff and erosion loss of fluazinam from the sloped land grown pepper. The WP type formulation was applied on July in 2003~2005. The wash-off rates were from 1.4% to 8.4% of the applied fluazinam. The runoff losses of fluazinam from a series of pepper grown-lysimeter plots were 0.14~0.90% in the first year, 0.01~0.04% in the second year and 0.16~0.37% in the third year for the mulched contour ridge plots, 0.47~1.59% for the mulched up-down direction ridge plots and 0.07~1.05% for the no-mulched contour ridge plots as the control, and they increased with slope degree. Concentrations of fluazinam in runoff water ranged mostly to 10 µ gL at the first runoff event. Erosion rates from plots except the mulched up-down direction ridge plots was 0.00~0.21% for 10% and 20% slope-plots and 0.15~1.05% for 30% slope-plots with different slope degrees. Erosion rates from the mulched up-down direction ridge plots were 0.47~1.59% for 10% slope-plots and 0.75~1.05% for 20% slope-plots. Residues of fluazinam in soil at ten days after the application ranged from 0.007 mg kg to 0.059 mg kg except the soil under the mulch. After then the fluazinam residue in soil was dissipated at the rate of 20 days of half-life to below 0.01 mg kg at 60 days after the application.

Effects of tillage practices on nutrient loss and soybean growth in red-soil slope farmland

Field experiments were conducted to examine the effect of tillage practices on sediment and nutrient loss and soybean growth under natural rainfall conditions. Three tillage practices were applied: downslope ridge (check) ,downslope ridge + contour living hedgerow,and cross ridge. Cross ridge tillage reduced surface runoff by 69% and sediment yield by 86% ,compared to the check treatment. The downslope ridge with a contour living hedgerow reduced surface runoff by 24% and sediment yield by 53% . Additionally,compared to the check plot ,nutrient losses carried by runoff were reduced by over 68% and that carried in the sediment was reduced more than 85% in the cross ridge plot. Nutrient losses in runoff were reduced by 20% to 30% in the downslope ridge and contour living hedgerow plot and those carried in the sediment were reduced by 44% to 57% . Cross ridge tillage soybean yields exceeded those of the downslope ridge and downslope ridge + contour living hedgerow treatments by 16% – 18% . Cross ridge tillage could contribute to the prevention sediment and nutrient loss and could improve crop yield, and thus it is recommended to be applied to mild slopes in the red soil region.

English

Contour ridging is a widely used soil and water conservation practice in Southern Africa. However, in recent years, a number of investigators questioned the effectiveness of contour ridges in controlling surface runoff and soil erosion from smallholder farmers’ fields. To be an effective conservation practice, contour ridges must store infiltration excess surface runoff as surface depression storage in furrows between the ridges. In this study, three experimental runoff plots were established in Chilindamaji and six in Kamundi watershed in Malawi. Of the six plots in Kamundi, three had agroforestry contour hedgerows (AF1, AF2, and AF3) and the other three (K1, K2, and K3) had no contour hedgerows. None of the Chilindamaji plots (C1, C2, and C3) had agroforestry contour hedgerows. Hydrologic response analysis of data obtained from the nine runoff plots revealed that plots that retained more water as infiltration and surface depression storage had less runoff and soil erosion. For both sites, the average soil loss rates for the bare, 50% residue cover, and the contour ridge plots were 115, 66, and 5 ton/ha/year. The average soil loss rates for the three agroforestry plots were 4.2 ton/ha/year. Our results show that 50% residue cover reduced soil loss as compared to a bare soil, but are not as effective as the contour ridge and the agroforestry contour hedgerow treatments in reducing surface runoff and soil loss.   Key words: Contour ridges, infiltration, runoff, soil loss, agroforestry, residue cover.

Structure, Species Composition, and Soil Characteristics in a Chronosequence of Jack Pine (Pinus banksiana Lamb.) Stands on the Southern Shore of Lake Michigan

We investigated the changes in stand structure, species composition, and soil characteristics of jack pine (Pinus banksiana Lamb.) disjunct stands on the southern shore of Lake Michigan in North America. Our NMS (Non-metric Multidimensional Scaling) ordination revealed a chronosequence of the succession from jack pine stand to black oak (Quercus velutina Lam.) woodland. A majority of jack pine seedlings appeared to be recruited near wet pannes (shallow intradunal ponds with standing water) where the water table was relatively high, expanded in dry pannes, and followed by invasions of black oak and other upland tree species on dune ridges. Expansion of canopy cover, along with dominance of black oak, have likely led to a major reduction in herbaceous cover and a shift in the composition of the understory species. Species richness and diversity have increased. However, much of the increase was attributed to species that were not native to the Lake Michigan sand dunes. Soil pH and nitrogen concentration changed significantly from the younger wet panne to the older dune ridge plots, but other measures of soil fertility did not differ among the plots. The reduction in soil pH in the older plots was likely due to the neutralization of calcareous soil by carbonic acid leached from accreted sands and organic acids produced by litter decomposition. Nitrogen accumulation in the soil is expected to continue beyond the equilibrium values predicted from mature oak woodland soil. Jack pine seedlings have been documented to be tolerant of xeric conditions. However, we found that seedling survival was over five times higher in moist soil near the wet pannes. In this respect, failure in formation of new pannes may reduce the size of the region's jack pine population in the foreseeable future.

실트펜스와 식생밭두렁 적용을 통한 밭 비점오염 저감효과 분석을 위한 포장실험 연구

The objective of this study was to test the pollutant reduction effect by the silt fence and vegetated ridge through field monitoring. The experiment plots were established with two replication and three treatments. Each plot was designed with 5 m width, 22 m length, and 3 % slope. Flumes with the floating type stage gages were installed at the outlet of each plot to monitor the runoff. For a rainfall monitoring, tipping bucket rain gage was installed within the experiment site. Cultivated crops were spring daikon and autumn chinese cabbage. Analysis of variance (ANOVA) indicated that the water quality concentration from three experiment plots were not significantly different in 5 % of significant level. The monitoring results showed that the average pollution loads reduced by silt fence compared to control were SS 75.33 %, TN 40.87 %, TP 56.58 %, BOD 52.12 %, COD 36.07 %, TOC 34.99 %; by vegetated ridge compard to control were SS 65.27 %, TN 81.80 %, TP 54.26 %, BOD 67.09 %, COD 46.55 %, TOC 43.30 %. Analysis of Spearman`s rank correlation coefficient showed that BOD-SS and SS-Turbidity were highly related at the silt fence and vegetated ridge plots. In all plots, SS-Turbidity and TP-TN relations were relatively high. The monitoring results showed that the silt fence and vegetated ridge were effect method to reduce the pollutant loads from the field runoff. Long-term monitoring is required to obtain more quantitative reduction effect for diverse crops and to increase the reliability of results.

Continuous wavelet transform based time-scale and multifractal analysis of the nonlinear oscillations in a hollow cathode glow discharge plasma

Continuous wavelet transform (CWT) based time-scale and multifractal analyses have been carried out on the anode glow related nonlinear floating potential fluctuations in a hollow cathode glow discharge plasma. CWT has been used to obtain the contour and ridge plots. Scale shift (or inversely frequency shift), which is a typical nonlinear behavior, has been detected from the undulating contours. From the ridge plots, we have identified the presence of nonlinearity and degree of chaoticity. Using the wavelet transform modulus maxima technique we have obtained the multifractal spectrum for the fluctuations at different discharge voltages and the spectrum was observed to become a monofractal for periodic signals. These multifractal spectra were also used to estimate different quantities such as the correlation and fractal dimension, degree of multifractality, and complexity parameters. These estimations have been found to be consistent with the nonlinear time series analysis.

Succession of a Southern Appalachian Mountain Wetland Six Years following Hydrologic and Microtopographic Restoration

Abstract Microtopography, which is known to play a key role in the structure and function of wetland communities, is receiving increasing attention in wetland restoration projects. One goal of the Tulula Wetlands Mitigation Bank, which was the first large‐scale wetland restoration project in the Blue Ridge Province, was to restore the microtopography in a degraded swamp forest–bog complex. This wetland type has become increasingly rare in the southern Appalachians and is characterized by a distinct microtopography of depressions and low ridges. We examined vegetation and soils in depression and ridge plots over a 6‐year period, during which the hydrology and microtopography of the floodplain were restored. Our results showed that the flora of the depression and ridge plots differed, with greater coverage by obligate wetland species in the depression plots but greater overall taxonomic richness in the ridge plots. The edaphic characteristics that we measured varied very little during the study period. Creating microtopographic relief during the restoration of this wetland seems to have provided a variety of niches and may have increased the likelihood that the site will succeed back to a swamp forest–bog complex, rather than as a forested terrace of Tulula Creek.

Phosphorus and iron erosion from non-vegetated sites in a post-mining landscape, Lusatia, Germany: Impact on aborning mining lakes

Abstract Particulate phosphorus (P) can be transported via soil erosion in overland flow to waters, where it provides a long-term source of P for aquatic biota, and can accelerate freshwater eutrophication. Hence, knowledge of P sources is important for good environmental management. However, data on P, and related Fe, losses from various structures of a post-mining landscape are lacking. A year-long monitoring, and ten short rainfall simulations on plot scale, at ridges and rills and a combination of them, revealed high erosion from bare lignite mining dumps at Schlabendorf-North, Lusatia, Germany. The mean annual soil erosion rate from the year-long monitoring site was 18 × 106 kg km− 2 yr− 1, corresponding to 0.034 g m− 2 min− 1. The erosion rates were lowest at rill plots (1.9–4.4 g m− 2 min− 1), intermediate at ridge plots (14.3–37.1 g m− 2 min− 1), and highest at a combined rill and ridge plot (48.7–63.4 g m− 2 min− 1). These differences in extent were due to small scale differences in morphology and extreme water repellency. The hydrophobicity leads to very low infiltration, thus generating surface runoff even at low rainfall intensities. Loss rates of P and Fe, as deduced from the year-long erosion rate, were 470–650 kg km− 2 yr− 1, and 37.9 × 103–71 × 103 kg km− 2 yr− 1 respectively. However, these P inputs from lignite mining dump erosion, consisting of P-poor (17–90 μg g− 1) tertiary spoil materials, into aborning mining lakes, are negligible since they are accompanied by high Fe inputs, which favour an efficient P co-precipitation in the water column.

On‐farm evaluation of ridging and residue management options in a Sahelian millet‐cowpea intercrop. 1. Soil quality changes

Abstract. In the Sahel, promising technologies for agricultural intensification include millet stover mulching and ridging. A four year on‐farm experiment was set‐up in order to assess the effect of various combinations of these two technologies on soil chemical and physical quality in a millet (Pennisetum glaucum (L.) R. Br.) –‐ cowpea (Vigna unguiculata (L.) Walp.) relay intercropping system. Treatments included bare surface, ridging, a surface applied banded millet stover mulch (2 t ha–1) and a banded millet stover mulch (2 t ha–1) buried in ridges. The latter three treatments were implemented exclusively in the cowpea rows, with an annual rotation between the millet and cowpea rows. Both the bare and ridge plots experienced a rapid loss of organic carbon, acidification and the development of extensive surface crusts but no increase in bulk density or penetration resistance. In the year of application, mulching improved soil quality in the cowpea row with respect to pH, organic carbon and exchangeable K+ and Mg++ content, penetration resistance and bulk density, and it reduced the decline in exchangeable Ca++ and total N content. In the year following mulch application, a general decline in soil chemical quality was observed in the millet row, except for organic carbon content, and a positive residual effect was observed on penetration resistance and bulk density. As a rule, the effects of mulching in the year of application tended to be stronger in the ridged treatment with buried residue than in the banded surface mulch. In the year following application, this tendency was reversed. For the purpose of reducing soil degradation by nutrient mining and wind erosion, a banded surface mulch therefore appeared more effective than buried mulch.

Influence of Site on Diversity and Abundance of Ground- and Litter-Dwelling Coleoptera in Appalachian Oak–Hickory Forests

Weevaluatedthefamily-levelrichness,diversity,evenness,andabundanceofground- and litter-dwelling beetles in two forested areas of southeastern Kentucky for 2 yr, and related beetle diversity to habitat characteristics in these deciduous forests. Using pitfall traps and leaf litter samples, we collected over 13,420 beetle specimens in 42 families during this 2-yr study. Carabidae, Scolytidae, and Staphylinidae were the most abundant families in pitfall traps, and Nitidulidae, Staphylinidae, and Pselaphidae were most common in litter samples. Pitfall traps captured the widest array, with 41 beetle families, whereas litter samples produced 25 families. Plots from Robinson Forest had a higher family richness but lower evenness than Kentucky Ridge Forest plots in both 1997 and 1998. The greater evenness of the families at Kentucky Ridge contributed to a higher Shannon index at Kentucky Ridge than at Robinson Forest, though these differences were significant only in 1998. Kentucky Ridge plots tended to be less rocky, with greater amounts of coarse woody debris, less dense herbaceous cover, a smaller mid-canopy component, and less deciduous cover than Robinson Forest. Family richness, diversity, evenness and abundance varied with site, plot, and sample interval, but the site variables we measured were inconsistent in their ability to predict our response variables, as was the multivariate cluster analysis. The effects of site characteristics and habitat complexity on beetle family diversity are discussed.

Soil macro‐invertebrates and litter disappearance in a Japanese mixed deciduous forest and comparison with European deciduous forests and tropical rainforests

AbstractSoil macro‐invertebrates and rate of litter disappearance were studied in a ridge plot with moder (mor) humus and a bottom plot with mull humus on a slope in a temperate mixed deciduous forest in Kyoto, Japan (J). The results were compared with those from two German beech forests (G) representative of European deciduous forest mor and mull. Between‐plot differences in biomass of total saprophagous animals was much smaller in J than in G, which is dominated by earthworms. Susceptibility to soil acidity and zoogeographical distribution of earthworms were suggested to be related to this situation. Biomass of soil macro‐invertebrates and litter turnover rate were compared among J, G and three types of tropical rainforests in Malaysia (M) in relation to climatic conditions. Taking into account among‐site differences in temperature and moisture, which affect microbial activity and in biomass of saprophagous macro‐invertebrates especially earthworms, the following order of importance of soil macro‐invertebrates in determining the rate of litter disappearance was suggested: G>J>M. Based on the comparison of biomass of earthworms among European deciduous forests, Japanese deciduous forests and tropical rainforests, as well as on the presence or absence of anecic earthworms in these forests, it was suggested that this ranking could be generalized to European deciduous forests > Japanese deciduous forests > tropical rainforests. It was pointed out that this order was the opposite of the gradient in evapotranspiration rate existing among these regions.

Lead isotope geochemistry of mississippi valley-type deposits of the Southern Appalachians

Lead isotope compositions of sphalerite, fluorite, barite and sparry dolomite in Mississippi Valley-type deposits of the southern Appalachians fall into four different isotopic groups. Most sphalerite forms two small clusters, whereas barite, fluorite, and sparry dolomite compositions are more scattered. These lead isotope compositions reflect the distribution of the deposits, which are hosted by two main palcoaquifers. Lower Cambrian clastic and carbonate rocks host the Austinville (Zn-Pb), Cartersville (Ba), Embreeville (Zn), and Doughtery (Zn) deposits, all of which fall in a cluster of lead isotope compositions near 207 Pb/ 204 Pb = 15.73 and 206 Pb/ 204 Pb = 19.45. Lower Ordovician carbonate rocks of the Knox Group host the Copper Ridge (Zn), Eve Mills (Zn), Greeneville-Fall Branch (Ba-F), Mascot-Jefferson City (Zn), Powell River (Zn-Pb), Russell-Tazewell (Ba-F), and Sweetwater (Ba-Zn-F) deposits, which have more complex compositions. Sphalerite from Mascot-Jefferson City, Eve Mills, Sweetwater, and Russell-Tazewell plots in a cluster around 207 Pb/ 204 Pb = 15.67 and 206 Pb/ 204 Pb = 19.0, whereas that from Copper Ridge plots in both clusters. Fluorite from Sweetwater falls on a long array in 207 Pb/ 204 Pb- 206 Pb/ 204 Pb space that has a two-stage age of 1.55 to 1.9 Ga for t 2 = 360 Ma, the previously published 87 Sr/ 86 Sr isochron age obtained for the Mascot-Jefferson City district. Barite and sparry dolomite compositions are relatively similar and have lower 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios than most sphalerite and fluorite. The spatial distribution of lead isotope compositions indicates that there were at least two mineralizing solutions, represented by the two lead clusters; the upper cluster solution dominated the Lower Ordovician palcoaquifer whereas the lower cluster dominated the Lower Cambrian palcoaquifer; and that the two solutions mixed in most areas except the Mascot-Jefferson City district, where zinc mineralization is strongest. Although the specific sources of these leads cannot be determined from available data on possible source rocks, the two lead clusters probably came from relatively young, well-mixed sedimentary basins and the lead in the fluorite must have come from a source with an unusally high U/Th ratio such as phosphoritc. This study confirms that the isotopic composition of lead in southern Appalachian Mississippi Valley-type deposits differs significantly from that found in mid-continent deposits.

ヤーコン（Ｐｏｌｙｍｎｉａ ｓｏｎｃｈｉｆｏｌｉａ）の栽培に関する研究 第６報 うねの作り方の相違が収量に及ぼす影響

We have been cultivation tests of Yacon (Polymnia sonchiforia) since 1987, and their results were reported. But it is not yet tested that the influence of ridging on the growth and yield of yacon.We tested on the influence of the methods of ridging on the growth and yield of yacon in Light-colored Andosol.Three experimental plots were made; level row plot, level row→high ridge (by earthing up) plot and high ridge plot. Three replications were made on each plot.The results were as follows:1) Growth of yacon of main stem in all stage was nonsignificant difference in each plot.2) The top was produced 748g/plant in level row plot, 900g/plant in level row→high ridge plot and 904g/plant in high ridge plot, but nonsignificant difference in each plot.3) The tuberous roots was produced 1268g/plant in level row plot, 1280g/plant in level row→high ridge plot and 1584g/plant in high ridge plot, but nonsignificant difference in each plot.4) From yield of yacon tuberous roots in each plot, it was suggestted that the earthing up at August 4, it would have little influence on yacon yield.5) From yield of yacon tuberous roots in each plot, it was judged that high ridge culture would be useful for the harvest of the tuberous roots of yacon with a potato digger.

Establishment of Native Grass Seedlings along a Topographic/Moisture Gradient in the Nebraska Sandhills

-This study examines the effect of differential survival of seedlings on the distribution of native grasses along topographic gradients in the Nebraska Sandhills. In 1981, seeds of three ridge species (Andropogon hallii, Sorghastrum nutans, Panicum virgatum) were planted into rototilled, irrigated, rototilled and irrigated, or untreated soils on three sites: one ridge site (ridge) and two valley sites (valley and lowland). The three sites represented a gradient of topography and soil moisture-holding capacity. For all species, seedling survival was greatest (86%) in the rototilled and irrigated treatment on the lowland site. No seedlings survived in untreated plots along the gradient. In 1982 and 1983, seeds of a ridge species (Andropogon hallii) and a valley species (Bouteloua gracilis) were planted in replicated ridge and valley plots. Seeds were planted into either untreated plots, or plots where plants received weekly clipping treatments around seedlings. Although clipping significantly increased survival of both species in both sites, it had a significantly greater effect in valley sites. In untreated plots, seedling survival was greatest (20%) in ridge sites in a year of average precipitation (1982) and in valley sites (49%) in a year that was exceptionally wet (1983). In 1983, soil moisture explained 98% of the variation in the survival of A. hallii seedlings and 82% in B. gracilis seedlings. Competition from existing vegetation severely limited the probability of seedling establishment. The distribution pattern of ridge species likely results from differential survival of juveniles and adults along the gradient, rather than the ability of seedlings to have higher establishment success on ridge sites. Significant establishment of the valley species (Bouteloua gracilis) occurred only during an exceptionally wet year when the pattern of survival of seedlings reflected the distribution pattern of adult plants. Establishment of prairie grass seedlings appears to depend on the availability of soil moisture, which may only be adequate in relatively large disturbance areas (> 1 m2), or in years of higher than normal precipitation.