Spatial Distribution Of Different Groups Research Articles

A micrometer-scale snapshot on phototroph spatial distributions: mass spectrometry imaging of microbial mats in Octopus Spring, Yellowstone National Park.

Microbial mats from alkaline hot springs in the Yellowstone National Park are ideal natural laboratories to study photosynthetic life under extreme conditions, as well as the nuanced interactions of oxygenic and anoxygenic phototrophs. They represent distinctive examples of chlorophototroph (i.e., chlorophyll or bacteriochlorophyll-based phototroph) diversity, and several novel phototrophs have been first described in these systems, all confined in space, coexisting and competing for niches defined by parameters such as light, oxygen, or temperature. In a novel approach, we employed mass spectrometry imaging of chloropigments, quinones, and intact polar lipids (IPLs) to describe the spatial distribution of different groups of chlorophototrophs along the~1cm thick microbial mat at 75µm resolution and in the top~1.5mm green part of the mat at 25µm resolution. We observed a fine-tuned sequence of oxygenic and anoxygenic chlorophototrophs with distinctive biomarker signatures populating the microbial mat. The transition of oxic to anoxic conditions is characterized by an accumulation of biomarkers indicative of anoxygenic phototrophy. It is also identified as a clear boundary for different species and ecotypes, which adjust their biomarker inventory, particularly the interplay of quinones and chloropigments, to prevailing conditions. Colocalization of the different biomarker groups led to the identification of characteristic IPL signatures and indicates that glycosidic diether glycerolipids are diagnostic for anoxygenic phototrophs in this mat system. The zoom-in into the upper green part further reveals how oxygenic and anoxygenic phototrophs share this microenvironment and informs on subtle, microscale adjustments in lipid composition of Synechococcus spp.

An integrated system of monitoring the availability, accessibility and attractiveness of urban parks and green squares

The main goal of this article is to propose a set of 20 indicators that represent barriers which prevent urban green space (UGS) provision on three levels – availability, accessibility, and attractiveness. These barriers include new investments, such as residential areas and roads; a lack of local zoning plans; fences and entrance fees; a lack of amenities, facilities and entrances; noise; particulates. To test our set of indicators, we investigated 115 parks and green squares in Lodz (Łódź), the third-largest city in Poland. We focused on parks as key examples of UGS, as they are the best explored and most recognizable spaces in most cities. We derived data for our analysis from thematic, publicly available maps and databases, and additional data were provided by managers of UGS. Moreover, we present the procedure of data processing and creating indicators by using the QGIS 2.18 software. Our analysis shows that very small parks in the city center are mostly fenced, lack park infrastructure, leisure facilities, and blue infrastructure, and people are exposed to different nuisances (noise, air pollution). In turn, parks with the lowest number of barriers are typically large and not in the city center. If compared with the spatial distribution of different groups of inhabitants and their socio-economic status, our results would show the actual availability, accessibility, and attractiveness. Our set of indicators is meant to facilitate further discussions with the different stakeholders, planners in particular, in order to remove barriers (at least partly) and increase the overall availability, accessibility, and attractiveness of UGS. Other indicators (based on those used in our article) can be constructed for the needs of other cities, but researchers should take into account data availability, the local context, institutional conditions, and UGS specificities. Besides, each case requires proper interpretation and individual consideration.

Geochemical characteristics and genetic origin of crude oil in the Fushan sag, Beibuwan Basin, South China Sea

Abstract The Fushan sag is an important petroleum-bearing unit in the Beibuwan Basin, South China Sea. However, genetic relationship between oil and source rocks has not been well understood. In this work, 43 mudstone samples and 22 crude oil samples in the sag were collected for molecular geochemical and isotopic analyses to investigate this relationship. The geochemical data shows that the mudstones in Liushagang formation have poor to good oil generation potential with TOC ranging from 0.45 to 2.19 wt% and the kerogen is mainly type Ⅱ. Two types of crude oils were identified in this study. The first type of Group A oils including the subgroup A1 and subgroup A2 has the characteristics of low maturity with low saturated hydrocarbon content and lighter δ13C values in the Huachang uplift. The source rocks for the Group A oils were deposited under suboxic to oxic and freshwater environment containing more terrestrial higher plant and less angiosperm. The subgroup A1 oils in Els11 reservoirs are separated from subgroup A2 in the Els12 reservoirs by relatively lower maturity. The subgroup A1 and subgroup A2 oils are closely related to the Els1 to Els21 and Els12 to Els21 source rocks, respectively. While the second type of oils including Group B and Group C oils has higher level of maturity with higher saturated hydrocarbon content and heavier δ13C values. The source rocks of Group B oils were deposited in a freshwater environment with lower salinity, and more angiosperms and terrestrial higher plants input than those of Group C oils. Two subgroups are divided in the Group B oils, of which subgroup B1 oils have higher maturity and their source rocks were deposited in lower salinity with more terrestrial higher plant input than that of subgroup B2 oils. The subgroup B1 oils occurring in the Els31 reservoirs from the Huachang uplift are likely related to Els31 source rocks, while subgroup B2 oils in the Els22 reservoirs from the southern slope area of the Bailian subsag is linked with mixed source of Els22 and Els31 mudstones. The Group C oils are distributed in Els22 and Els31 reservoirs in the Huachang uplift and their oil source are from Els32 mudstones. Two petroleum plays are likely divided by the mfs in Els2 based on the oil-source correlation in the sag. Group B and Group C oils belong to the lower play, and Group A oils only occur in the upper play. The distribution and accumulation of different groups of oils are mainly controlled by the special two-layered tectonostratigraphic framework and the transport ability of fault zone in the sag. This study clarifies the types of oils, as well as the oil-source correlation and the spatial distribution of different groups of oils. The results could benefit the further petroleum exploration and resource evaluation in the sag.

Internal Differentiation within the Rural Migrant Population from the Sustainable Urban Development Perspective: Evidence from China

Population mobility and attendant issues, especially housing issues, have a major impact on sustainable urban development. In the urbanization process, a number of micro-communities with various social characteristics have come to compose the rural migrant population (RMP), resulting in internal differentiation. This study aims to reveal the demographic structure of this specific group, and to analyze the effects of the mechanism between population flow trends and sustainable urban development, taking housing demand as a starting point. To this end, a clustering model for mixed-type data based on partitioning around the medoid is proposed, and the linked characteristics and potential laws of the RMP are analyzed, based on the dynamic data of the migrant population in eastern China. To achieve sustainable urban development, the locational preferences and coping strategies of inflowing micro-communities based on city types are demonstrated. The results show that the RMP can be divided into four groups that have strong representativeness and that show significant differences in population structure and housing demand. Super-large and medium-sized cities are the main migration destinations. Several suggestions are proposed, based on these results. Housing security policies should be designed according to the housing demand characteristics and the spatial distribution of different groups. Housing security policies should play a full and positive role in reasonably guiding RMP movement.

Multielement geochemistry identifies the spatial pattern of soil and sediment contamination in an urban parkland, Western Australia

Urban environments are dynamic and highly heterogeneous, and multiple additions of potential contaminants are likely on timescales which are short relative to natural processes. The likely sources and location of soil or sediment contamination in urban environment should therefore be detectable using multielement geochemical composition combined with rigorously applied multivariate statistical techniques. Soil, wetland sediment, and street dust was sampled along intersecting transects in Robertson Park in metropolitan Perth, Western Australia. Samples were analysed for near-total concentrations of multiple elements (including Cd, Ce, Co, Cr, Cu, Fe, Gd, La, Mn, Nd, Ni, Pb, Y, and Zn), as well as pH, and electrical conductivity. Samples at some locations within Robertson Park had high concentrations of potentially toxic elements (Pb above Health Investigation Limits; As, Ba, Cu, Mn, Ni, Pb, V, and Zn above Ecological Investigation Limits). However, these concentrations carry low risk due to the main land use as recreational open space, the low proportion of samples exceeding guideline values, and a tendency for the highest concentrations to be located within the less accessible wetland basin. The different spatial distributions of different groups of contaminants was consistent with different inputs of contaminants related to changes in land use and technology over the history of the site. Multivariate statistical analyses reinforced the spatial information, with principal component analysis identifying geochemical associations of elements which were also spatially related. A multivariate linear discriminant model was able to discriminate samples into a-priori types, and could predict sample type with 84% accuracy based on multielement composition. The findings suggest substantial advantages of characterising a site using multielement and multivariate analyses, an approach which could benefit investigations of other sites of concern.

The transition of human subsistence strategies in relation to climate change during the Bronze Age in the West Liao River Basin, Northeast China

Despite the proposed climate–human connection in the West Liao River Basin during the Bronze Age, the question of how climate change could have affected the subsistence strategies, and consequently, the cultural transformation from the Lower Xiajiadian to the Upper Xiajiadian periods, has never been systematically explored. Based on radiocarbon dating and the analysis of plant remains recovered by flotation, as well as the spatial distribution of archaeological sites, this study investigates the subsistence strategies of ancient people and their influence on cultural development in the West Liao River Basin during the Lower Xiajiadian (3900–3400 cal. yr BP) and Upper Xiajiadian periods (3000–2500 cal. yr BP). Carbonized seeds collected from 13 archaeological sites reveal that people engaged in millet-based agriculture in this area throughout the Bronze Age. Favorable climate during the Holocene Optimum promoted millet farming among the Lower Xiajiadian Culture. The end of the Holocene Optimum and its associated climate deterioration led to agricultural shrinkage in the Upper Xiajiadian period, which is revealed by the reduced amount of carbonized millet seeds and the ratio between foxtail millet and broomcorn millet. Climate deterioration led to diverse subsistence strategies, resulting in the dispersal of human settlements and the differentiation of the spatial distributions of different groups. People with millet-based subsistence strategies retreated southward, while people with animal husbandry and hunting-based subsistence strategies migrated westward. The above findings may offer insights in comprehending how climate deterioration could have affected the multi-facets of human societies in the West Liao River Basin, which is a climatically sensitive region, in Chinese prehistory.

Helmintic infections in water buffaloes on Italian farms: a spatial analysis

The present paper reports the results of a cross-sectional survey aimed at obtaining up-to-date information on the spatial distribution of different groups and/or species of helminths in water buffaloes from central Italy. Geographical information systems (GIS) and spatial analysis were used to plan the sampling procedures, to display the results as maps and to detect spatial clusters of helminths in the study area. The survey was conducted on 127 water buffalo farms, which were selected in the study area using a grid sampling approach, followed by proportional allocation. Faecal samples (n. = 1,883) collected from the 127 farms were examined using the Flotac dual technique. Gastrointestinal strongyles were the most frequent helminths (33.1%) on the tested farms, followed by the liver fluke Fasciola hepatica (7.1%), the rumen fluke Calicophoron daubneyi (7.1%), the nematode Strongyloides spp. (3.1%), the lancet liver fluke Dicrocoelium dendriticum (2.4%) and the tapeworm Moniezia spp. (2.4%). In order to display the spatial distribution of the various helminths detected on the water buffalo farms (used as epidemiological unit in our study), point maps were drawn within the GIS. In addition, for each helminth, clustering of test-positive farms were investigated based on location determined by exact coordinates. Using spatial scan statistic, spatial clusters were found for the flukes F. hepatica and C. daubneyi and the cestode Moniezia spp.; these findings are consistent with the life cycle of these parasites, which have strong environmental determinants. In conclusion, the present study demonstrated that, with the appropriate survey-based data at hand, GIS is a useful tool to study epidemiological patterns of infections in veterinary health, in particular in water buffaloes.

Models of Spatial Structures of Regional Multi‐element Geochemical Anomalies over Copper‐Polymetallic Orefields

Abstract Regional stream sediment surveys at a 1:200,000 scale reveal positive and negative regional multi‐element geochemical anomalies over medium to large copper‐polymetallic orefields of different genetic types in China. Regional geochemical anomalies of orefield refer to those geochemical anomalies that are related to metallogenesis of an orefield in a certain area. The anomaly area is typically 10 to 100 km2. The regional multi‐element anomalies related to mineralization can be divided into three groups, that is, the ore‐element anomaly association, indicator element anomaly association, and metallogenic environmental element anomaly association. Their common spatial distributions over ore deposits or orefields possess unique structures.The model of spatial structure of regional multi‐element geochemical anomalies (RAGSS) of an orefield delineates structural feature possessed by orderly spatial distributions of different groups of multi‐element anomaly associations related to orefield metallogenesis. It is used to outline the common metallogenetic anomaly visage that is composed of the orderly spatial distribution of different groups of multi‐element anomaly associations. The orderly spatial distribution of multi‐element anomalies over an orefield reflects element distributions as they are changed from a dispersed “out‐of‐order” state into a concentrated “orderly” state during the mineralization of an orefield.Three different patterns of the spatial anomaly structure related to mineralization in an orefield can be concluded: (1) nested pattern; (2) eccentric pattern and; (3) peripheral pattern. There are marked differences between multi‐element anomaly patterns related and not related to mineralization. RAGSS models of orefields can be used to better understand and evaluate regional multi‐element anomalies and identify ore types.

Anisotropies in the Motions and Positions of the Galactic Globular Clusters

The velocity ellipsoid for 38 globular clusters with [Fe/H] <= -1.0 is derived and shown to be significantly anisotropic with major axis directed towards low Galactic latitude. Principal axes of the spatial distribution of different groups of clusters are derived and compared with the velocity ellipsoid. The metal poor cluster spatial distribution is significantly flattened along an axis which coincides within the uncertainties with the major axis of the velocity ellipsoid. Given the observed steep age-metallicity relation for metal poor clusters, one speculative interpretation of the data is that an initially flattened filament underwent a relatively rapid initial transverse collapse forming satellite galaxies and metal poor globular clusters while the protogalaxy collapsed and assembled more slowly along the filament acquiring and/or redistributing angular momentum in the process.

Exploring changes in the spatial distribution of livestock in China

China's livestock sector is very dynamic as a consequence of increasing demands for animal products. This paper explores the spatial distribution of different groups of livestock in China. Relations between the spatial pattern of livestock distribution and a large number of socio-economic and biophysical variables have been derived by correlation and regression analysis. The thus derived relations are used in a spatially explicit, dynamic simulation model to explore near-future changes in land use and livestock distribution. A baseline scenario and a scenario with improved management of grasslands are evaluated. The results indicate that for both scenarios most increases in livestock numbers are to be expected in China's agricultural region.

Hrp-labeled sources of descending propriospinal pathways in cats

Unilateral injections of horseradish peroxidase into the cat spinal cord at different segmental levels revealed a laminar distribution of spinal interneurons that are sources of ipsilateral and contralateral propriospinal pathways of different lengths. The majority of the long pathways connecting cervical and lumbar segments are formed by neurons located in the central quadrants (laminae VII and VIII) bilaterally; a few such neurons also are present in the marginal layer and in lateral zones at the base of the dorsal horn (ipsilaterally). The zones containing numerous propriospinal neurons forming short (extending over a few segments) connections were more extensive. In the lumbar portion neurons which were sources of short uncrossed pathways tended to be concentrated in the lateral areas of the base of the dorsal horn, intermediate zone, and ventral horn, whereas sources of crossed pathways were concentrated in the ventromedial zones of gray matter. In the cervical portion "short" propriospinal neurons forming both ipsilateral and contralateral projections were concentrated in the lateral zones of gray matter. Neurons of the marginal layer and substantia gelatinosa and neurons of intermediolateral sympathetic nuclei also were sources of descending propriospinal pathways. Some propriospinal axons were intermediate in length. The distribution of neurons with axons of this kind largely coincided with the distribution of neurons that were sources of long propriospinal pathways. The connection between the spatial distribution of different groups of propriospinal neurons and the organization of the synaptic inputs into them, and also correlation between the morphological and functional characteristics of these neurons are discussed.