Uniform Pool Research Articles

The functional role of spatial anisotropies in ensemble perception.

The human brain can rapidly represent sets of similar stimuli by their ensemble summary statistics, like the average orientation or size. Classic models assume that ensemble statistics are computed by integrating all elements with equal weight. Challenging this view, here, we show that ensemble statistics are estimated by combining parafoveal and foveal statistics in proportion to their reliability. In a series of experiments, observers reproduced the average orientation of an ensemble of stimuli under varying levels of visual uncertainty. Ensemble statistics were affected by multiple spatial biases, in particular, a strong and persistent bias towards the center of the visual field. This bias, evident in the majority of subjects and in all experiments, scaled with uncertainty: the higher the uncertainty in the ensemble statistics, the larger the bias towards the element shown at the fovea. Our findings indicate that ensemble perception cannot be explained by simple uniform pooling. The visual system weights information anisotropically from both the parafovea and the fovea, taking the intrinsic spatial anisotropies of vision into account to compensate for visual uncertainty.

Optimizing SARS-CoV-2 Pooled Testing Strategies Through Differentiated Pooling for Distinct Groups.

Pooled testing has been successfully used to expand SARS-CoV-2 testing, especially in settings requiring high volumes of screening of lower-risk individuals, but efficiency of pooling declines as prevalence rises. We propose a differentiated pooling strategy that independently optimizes pool sizes for distinct groups with different probabilities of infection to further improve the efficiency of pooled testing. We compared the efficiency (results obtained per test kit used) of the differentiated strategy with a traditional pooling strategy in which all samples are processed using uniform pool sizes under a range of scenarios. For most scenarios, differentiated pooling is more efficient than traditional pooling. In scenarios examined here, an improvement in efficiency of up to 3.94 results per test kit could be obtained through differentiated versus traditional pooling, with more likely scenarios resulting in 0.12 to 0.61 additional results per kit. Under circumstances similar to those observed in a university setting, implementation of our strategy could result in an improvement in efficiency between 0.03 to 3.21 results per test kit. Our results can help identify settings, such as universities and workplaces, where differentiated pooling can conserve critical testing resources.

Face-Based CNN on Triangular Mesh with Arbitrary Connectivity

Applying convolutional neural networks (CNNs) to triangular meshes has always been a challenging task. Because of the complex structure of the meshes, most of the existing methods apply CNNs indirectly to them, and require complex preprocessing or transformation of the meshes. In this paper, we propose a novel face-based CNN, which can be directly applied to triangular meshes with arbitrary connectivity by defining face convolution and pooling. The proposed approach takes each face of the meshes as the basic element, similar to CNNs with pixels of 2D images. First, the intrinsic features of the faces are used as the input features of the network. Second, a sort convolution operation with adjustable convolution kernel sizes is constructed to extract the face features. Third, we design an approximately uniform pooling operation by learnable face collapse, which can be applied to the meshes with arbitrary connectivity, and we directly use its inverse operation as unpooling. Extensive experiments show that the proposed approach is comparable to, or can even outperform, state-of-the-art methods in mesh classification and mesh segmentation.

Cultural Adaptation of Loan Words in Mosuli Arabic: A Sociolinguistic Study.

This paper investigates the cultural adaptation of loan words in Mosuli Arabic from a sociolinguistic perspective. It aims at investigating the extent of the sociolinguistic factors, namely: age, gender, social class and educational attainment, influence on loan words usage in Mosuli speech community and also investigating the effect of the environmental factor, in terms of the surrounding regional effect, on Mosuli Arabic. It is hypothesised that the sociolinguistic factors have influence on the rate of loan words usage in that community and that the environmental factor has influential effect in entering loan words into it. To achieve all these, a sociolinguistic modified model is adopted which is based on a theoretical framework, namely: Poplack et al (1988). Informal interviews are conducted with forty-eight native Mosuli speakers divided equally according to sociolinguistic factors (namely: age, gender, social class and educational level) to calculate the rate of loan words used by each subgroup and, then, analysed in the light of the adopted model. This study finds that the sociolinguistic factors affect loan words usage in Mosuli Arabic. Although Mosuli speech community has a shared strategy for incorporating loan words into Mosuli Arabic discourse and that there is a uniform pool of loan words in Mosuli speech community and each speaker chooses from this pool, there is a slight tendency for one subgroup to use loan words rather than its counterpart. It is observed that female, old age, low class and illiterate groups incline to use loan words rather than their counterparts.

Uniform spatial pooling explains topographic organization and deviation from receptive-field scale invariance in primate V1

Receptive field (RF) size and preferred spatial frequency (SF) vary greatly across the primary visual cortex (V1), increasing in a scale invariant fashion with eccentricity. Recent studies reveal that preferred SF also forms a fine-scale periodic map. A fundamental open question is how local variability in preferred SF is tied to the overall spatial RF. Here, we use two-photon imaging to simultaneously measure maps of RF size, phase selectivity, SF bandwidth, and orientation bandwidth—all of which were found to be topographically organized and correlate with preferred SF. Each of these newly characterized inter-map relationships strongly deviate from scale invariance, yet reveal a common motif—they are all accounted for by a model with uniform spatial pooling from scale invariant inputs. Our results and model provide novel and quantitative understanding of the output from V1 to downstream circuits.

Transcription factor expression defines subclasses of developing projection neurons highly similar to single-cell RNA-seq subtypes.

We are only just beginning to catalog the vast diversity of cell types in the cerebral cortex. Such categorization is a first step toward understanding how diversification relates to function. All cortical projection neurons arise from a uniform pool of progenitor cells that lines the ventricles of the forebrain. It is still unclear how these progenitor cells generate the more than 50 unique types of mature cortical projection neurons defined by their distinct gene-expression profiles. Moreover, exactly how and when neurons diversify their function during development is unknown. Here we relate gene expression and chromatin accessibility of two subclasses of projection neurons with divergent morphological and functional features as they develop in the mouse brain between embryonic day 13 and postnatal day 5 in order to identify transcriptional networks that diversify neuron cell fate. We compare these gene-expression profiles with published profiles of single cells isolated from similar populations and establish that layer-defined cell classes encompass cell subtypes and developmental trajectories identified using single-cell sequencing. Given the depth of our sequencing, we identify groups of transcription factors with particularly dense subclass-specific regulation and subclass-enriched transcription factor binding motifs. We also describe transcription factor-adjacent long noncoding RNAs that define each subclass and validate the function of Myt1l in balancing the ratio of the two subclasses in vitro. Our multidimensional approach supports an evolving model of progressive restriction of cell fate competence through inherited transcriptional identities.

Uniform Pooling for Graph Networks

The graph convolution network has received a lot of attention because it extends the convolution to non-Euclidean domains. However, the graph pooling method is still less concerned, which can learn coarse graph embedding to facilitate graph classification. Previous pooling methods were based on assigning a score to each node and then pooling only the highest-scoring nodes, which might throw away whole neighbourhoods of nodes and therefore information. Here, we proposed a novel pooling method UGPool with a new point-of-view on selecting nodes. UGPool learns node scores based on node features and uniformly pools neighboring nodes instead of top nodes in the score-space, resulting in a uniformly coarsened graph. In multiple graph classification tasks, including the protein graphs, the biological graphs and the brain connectivity graphs, we demonstrated that UGPool outperforms other graph pooling methods while maintaining high efficiency. Moreover, we also show that UGPool can be integrated with multiple graph convolution networks to effectively improve performance compared to no pooling.

Systematic evaluation of the early access applied biosystems precision ID Globalfiler mixture ID and Globalfiler NGS STR panels for the ion S5 system

Systematic evaluation of the early access applied biosystems precision ID Globalfiler mixture ID and Globalfiler NGS STR panels for the ion S5 system

Shell-side boiling of a glycerol-water mixture at low sub-atmospheric pressures

Experimental data are reported for boiling water and a glycerol-water mixture at a free surface pressure of 50mbar absolute on the shell-side of a thin slice model of an industrial boiler. The boiler test section was 1m high, 0.75m wide, 98mm long and contained 36 electrically heated, horizontal tubes that were 28.5mm in diameter. The design of the boiler ensured that the tubes were submerged in a liquid pool. The height of the liquid pool was set to 2m, submerging the top of the tube bundle in 1.6m of liquid. The heat flux was varied within the range 10–65kW/m2. A near-symmetrical half of the tube bundle contained wall thermocouples. An additional 29 thermocouples were located throughout the liquid pool.For both fluids, the liquid temperature in the pool was found to be reasonably uniform and controlled by the pressure at the free surface. This led to subcoolings of up to 31K on the tube surfaces. The reasonably uniform pool temperature suggests that the liquid re-circulates within it.For water, boiling was initiated in the heat flux range 25–40kW/m2, whereas the glycerol-water mixture initiated boiled within the range 10–25kW/m2. Below these heat flux ranges, both fluids were in natural convection, with the measured wall superheats in reasonable agreement with predictions from a correlation available in the open literature. The difference in the fluids’ boiling onset resulted from the natural convection, heat-transfer coefficients of the glycerol-water mixture being lower than that for water. The boiling wall superheats for water were reasonably well predicted by a correlation available in the open literature.Boiling glycerol-water mixture data, taken at atmospheric pressure and available in the open literature, was used to identify methods for correcting pure fluid boiling heat-transfer coefficients for mixture effects. Mixture boiling superheats were reasonably well predicted by some of these methods. The method that worked best at atmospheric pressure did not work best at low pressure. A method is identified that is reasonable at atmospheric and low pressures.

Shell-side boiling of water at sub-atmospheric pressures

Experimental data are reported for water boiling at pressures of 850 and 50mbar absolute on the shell-side of a model industrial boiler slice. The boiler test section was 1m high, 0.75m wide and contained 36 electrically heated tubes. The tubes were 28.5mm in diameter and 98mm long. The design of the boiler ensured that the tubes were submerged in a liquid pool. The height of the liquid pool could be varied. The pool height was set to approximately 0.8m for the tests carried out at a pressure of 850mbar, submerging the top of the tube bundle by about 200mm. Two pool heights were used in the tests carried out at a pressure of 50mbar, one at approximately 0.8m and another at approximately 2m. The later submerged the top of the tube bundle by about 1.6m. The heat flux was varied within the range 10–70kW/m2. A near-symmetrical half of the tube bundle contained wall thermocouples. An additional 29 thermocouples were located throughout the liquid pool.The liquid temperature in the pool was found to be reasonably uniform and controlled by the pressure at the free surface. This led to a small amount of subcooling at a pressure of 850mbar, up to 3K, and a significant amount of subcooling at a pressure of 50mbar, up to 16K for the smaller pool height and up to 31K for the larger pool height. The reasonably uniform pool temperature suggests that the liquid re-circulates within it.Boiling was found to occur at all heat fluxes at a pressure of 850mbar, with the measured heat-transfer coefficients shown to be in broad agreement with nucleate boiling correlations available in the open literature. However, they were also consistent with a flow boiling process involving natural convection and nucleation, where the convection was driven by variations in liquid temperature on the walls of the tubes. This natural convection relies on an interaction between the tubes that produces mass fluxes in the range 46–87kg/m2s, based on the approach area to the tube bundle. Boiling occurred only at the higher heat fluxes during the low level tests at a pressure of 50mbar, with interactive natural convection being the dominant heat-transfer mechanism. The mass fluxes produced were in the range 28–70kg/m2s. Boiling also occurred only at the higher heat fluxes during the high level tests at a pressure of 50mbar. However, the convective heat transfer was more compatible with little interaction between the tubes, although some evidence suggests that the evaporator oscillates between interactive and isolated tube behaviour.

In situ serial Laue diffraction on a microfluidic crystallization device.

Renewed interest in room-temperature diffraction has been prompted by the desire to observe structural dynamics of proteins as they function. Serial crystallography, an experimental strategy that aggregates small pieces of data from a large uniform pool of crystals, has been demonstrated at synchrotrons and X-ray free-electron lasers. This work utilizes a microfluidic crystallization platform for serial Laue diffraction from macroscopic crystals and proposes that a collection of small slices of Laue data from many individual crystals is a realistic solution to the difficulties in dynamic studies of irreversible biochemical reactions.

Transient refractory material dissolution by a volumetrically-heated melt

The present work addresses the question of corium–ceramic interaction in a core catcher during a core-melt accident in a nuclear power plant. It provides an original insight into transient aspects concerning dissolution of refractory material by a volumetrically heated pool. An experiment with simulant material (LIVECERAM) is presented.Test results clearly show that dissolution of solid refractory material can occur in a non-eutectic melt at a temperature which is lower than the melting temperature of the refractory material. During the dissolution transient, the interface temperature rises above the liquidus temperature, corresponding to the instantaneous average composition of the melt pool.With constant power dissipation in the melt and external cooling of the core-catcher, a final steady-state situation is reached. Dissolution stops when the heat flux (delivered by the melt to the refractory) can be removed by conduction through the residual thickness of the ceramic, with Tinterface=Tliquidus (calculated for the average composition of the final liquid pool). The final steady state corresponds to a uniform pool composition and uniform interface temperature distribution. Convection in the pool is governed by natural thermal convection and the heat flux distribution is therefore similar to what would be obtained for a single component pool.An interpretation of the experiment with two model-based approaches (0D and 1D) is presented. The mass transfer kinetics between the interface and the bulk is controlled by a diffusion sublayer within the boundary layer. During the dissolution transient, the liquid composition at the interface is concentrated in the refractory species. During the transient, the interface temperature is equal to the liquidus temperature corresponding to the local and instantaneous composition of the liquid at the interface.Regarding the design of a protective layer made of refractory materials, we can answer the question of how much ceramic can be dissolved and its impact on melt temperature evolution during the dissolution process. It also impacts on subsequent corium solidification since the additional mass of dissolved ceramic leads to increased volume of the molten material, significantly increasing the time required for complete solidification. For the long term, ceramic material does not offer better confinement than a crust made of solidified corium.This work served as support to a generalisation of the model of transient evolution of interface temperature in various severe accident situations (Seiler and Combeau, 2014).

Topographical Analysis of the Subependymal Zone Neurogenic Niche

The emerging model for the adult subependymal zone (SEZ) cell population indicates that neuronal diversity is not generated from a uniform pool of stem cells but rather from diverse and spatially confined stem cell populations. Hence, when analysing SEZ proliferation, the topography along the anterior-posterior and dorsal-ventral axes must be taken into account. However, to date, no studies have assessed SEZ proliferation according to topographical specificities and, additionally, SEZ studies in animal models of neurological/psychiatric disorders often fail to clearly specify the SEZ coordinates. This may render difficult the comparison between studies and yield contradictory results. More so, by focusing in a single spatial dimension of the SEZ, relevant findings might pass unnoticed. In this study we characterized the neural stem cell/progenitor population and its proliferation rates throughout the rat SEZ anterior-posterior and dorsal-ventral axes. We found that SEZ proliferation decreases along the anterior-posterior axis and that proliferative rates vary considerably according to the position in the dorsal-ventral axis. These were associated with relevant gradients in the neuroblasts and in the neural stem cell populations throughout the dorsal-ventral axis. In addition, we observed spatially dependent differences in BrdU/Ki67 ratios that suggest a high variability in the proliferation rate and cell cycle length throughout the SEZ; in accordance, estimation of the cell cycle length of the neuroblasts revealed shorter cell cycles at the dorsolateral SEZ. These findings highlight the need to establish standardized procedures of SEZ analysis. Herein we propose an anatomical division of the SEZ that should be considered in future studies addressing proliferation in this neural stem cell niche.

Estimation of fish and wildlife disease prevalence from imperfect diagnostic tests on pooled samples with varying pool sizes

Methods of estimating disease or parasite prevalence in free-ranging and some captive fish and wildlife populations are frequently lacking in precision due to limited numbers of observations and different assay procedures. Recently statistical methods and software programs have been developed to use Bayesian and other methods to obtain estimates of disease prevalence from diagnostic tests in which sensitivity and/or specificity is not perfect (imperfect) and with sampling schemes using pooled samples. However, these published methods and software programs that consider pooled data sampling have generally considered the case of one uniform pool size for all samples. We present a method for estimating disease prevalence from imperfect diagnostic tests with pooled data collected from a variety of pool sizes. We use a Bayesian approach and obtain a sample from the posterior distribution of prevalence, sensitivity, and specificity, using an MCMC sampling algorithm implemented in the WINBUGS statistical package. We illustrate the use of these methods with three examples and perform efficiency calculations to investigate the performance of these estimators relative to maximum likelihood estimators that assume perfect diagnostic tests. Our results illustrate that the estimates produced from these methods adjust for imperfect tests, and are often more efficient than estimates assuming perfect tests, except in some situations when there is not much prior information on diagnostic test sensitivity and specificity.

Distinct Hematopoietic Stem Cell Subtypes Are Differentially Regulated by TGF-β1

The traditional view of hematopoiesis has been that all the cells of the peripheral blood are the progeny of a unitary homogeneous pool of hematopoietic stem cells (HSCs). Recent evidence suggests that the hematopoietic system is actually maintained by a consortium of HSC subtypes with distinct functional characteristics. We show here that myeloid-biased HSCs (My-HSCs) and lymphoid-biased HSCs (Ly-HSCs) can be purified according to their capacity for Hoechst dye efflux in combination with canonical HSC markers. These phenotypes are stable under natural (aging) or artificial (serial transplantation) stress and are exacerbated in the presence of competing HSCs. My- and Ly-HSCs respond differently to TGF-beta1, presenting a possible mechanism for differential regulation of HSC subtype activation. This study demonstrates definitive isolation of lineage-biased HSC subtypes and contributes to the fundamental change in view that the hematopoietic system is maintained by a continuum of HSC subtypes, rather than a functionally uniform pool.

A Proteome-Wide Perspective on Peroxisome Targeting Signal 1(PTS1)-Pex5p Affinities

Most proteins are targeted to the peroxisomal matrix by virtue of a peroxisomal targeting signal-1 (PTS1), a short carboxy-terminal sequence specifically recognized by the PTS1 receptor Pex5p. We had previously developed a model that allowed the estimation of the affinities of many PTS1 sequences within the human proteome for Pex5p that revealed a wide range of predicted affinities. We have now experimentally determined the affinities of the PTS1-containing peptides from 42 proteins from the human proteome for Pex5p and show that these range over 4 orders of magnitude. These affinities correlate reasonably well with the predicted values and are substantially more precise. In an attempt to provide a possible explanation for the wide range of PTS1-Pex5p affinities, we compared these affinities with mRNA levels (as a proxy for rates of protein production) of the genes encoding these proteins in 79 human tissues and cell types. We note that high affinity PTS1-Pex5p interactions tend to correspond to proteins encoded by genes expressed at relatively low levels, whereas lower affinity PTS1-Pex5p interactions tend to correspond to proteins encoded by genes exhibiting higher levels and wider ranges of expression. Further analysis revealed that these relationships are consistent with the notion that a relatively uniform pool of protein-Pex5p complexes is maintained for appropriate peroxisome assembly.

Subcellular distribution of proteolytically generated valine in isolated rat hepatocytes.

1. A small fraction of the intracellular acid-soluble radioactivity in [14C]valine-labelled hepatocytes remained non-extracted even after repeated incubations in isotope-free medium at 37 degrees C. This non-extracted radioactivity was only present when the cells had been labelled under conditions allowing protein synthesis. 2. Approximately two-thirds of the non-extracted radioactivity was recovered in material with a molecualr weight larger than free valine, i.e. presumably acid-soluble peptides. The intracellular contents of these peptides were unaffected by inhibitors of hepatocytic protein degradation, and they would therefore seem to represent primary synthesis products rather than products of proteolysis. 3. The remaining one-third of the radioactivity was free [14C]valine, derived from intracellular protein degradation as indicated by the reduced levels seen in the presence of inhibitors of lysosomal (ammonia, methylamine, leupeptin, chymostatin) and non-lysosomal (chymostatin) proteolysis. The intracellular levels of twelve other amino acids were similarly reduced upon inhibition of protein degradation. 4. The contents of free [14C]valine in subcellular fractions were compatible with a uniform distribution of the amino acid throughout the cell. There was no evidence for any enrichment of [14C]valine in a purified lysosomal fraction, separated from mitochondria by means of isotonic metrizamide gradients. 5. It can be concluded that the non-extracted valine in hepatocytes may represent a steady-state level, maintained by intracellular protein degradation, of amino acid in transit through the cell. The non-extractability, i.e. the maintenance of a concentration gradient towards the extracellular medium, can be calculated to be compatible with a limitation of valine efflux by the concentration-dependent valine transport system. Since no specific subcellular compartmentation is indicated, intracellular valine can provisionally be regarded as a single, uniform pool.

Structure, function and evolution of the gas exchangers: comparative perspectives.

Over the evolutionary continuum, animals have faced similar fundamental challenges of acquiring molecular oxygen for aerobic metabolism. Under limitations and constraints imposed by factors such as phylogeny, behaviour, body size and environment, they have responded differently in founding optimal respiratory structures. A quintessence of the aphorism that 'necessity is the mother of invention', gas exchangers have been inaugurated through stiff cost-benefit analyses that have evoked transaction of trade-offs and compromises. Cogent structural-functional correlations occur in constructions of gas exchangers: within and between taxa, morphological complexity and respiratory efficiency increase with metabolic capacities and oxygen needs. Highly active, small endotherms have relatively better-refined gas exchangers compared with large, inactive ectotherms. Respiratory structures have developed from the plain cell membrane of the primeval prokaryotic unicells to complex multifunctional ones of the modern Metazoa. Regarding the respiratory medium used to extract oxygen from, animal life has had only two choices--water or air--within the biological range of temperature and pressure the only naturally occurring respirable fluids. In rarer cases, certain animals have adapted to using both media. Gills (evaginated gas exchangers) are the primordial respiratory organs: they are the archetypal water breathing organs. Lungs (invaginated gas exchangers) are the model air breathing organs. Bimodal (transitional) breathers occupy the water-air interface. Presentation and exposure of external (water/air) and internal (haemolymph/blood) respiratory media, features determined by geometric arrangement of the conduits, are important features for gas exchange efficiency: counter-current, cross-current, uniform pool and infinite pool designs have variably developed.

Carbon turnover (δ 13C) and nitrogen mineralization potential of particulate light soil organic matter after rainforest clearing

Soil samples from under a rainforest, a papaya plantation, a pure Brachiaria humidicola pasture and a B. humidicola/Desmodium ovalifolium sward from the humid tropical Bahia, Brazil, were analyzed for fertility parameters, litter quality, particulate light fraction [ PLF> 100 53 -100 μ m , < 1.8 g cm −3 density (sodium polytungstate)] and δ 13C signatures. Under the grass pasture total soil C was reduced to 80 and 95% of the initial forest value after 18 years in the surface 2 cm and the 5–15 cm horizons, respectively, largely due to the sharp decline in rainforest-derived C after deforestation. Losses of rainforest-derived C amounted to 73% (0–2 cm) and 40% (5–15 cm) of the initial soil C content. The contribution of newly added B. humidicola-derived soil C was estimated to be 24 and 5 mg C g −1 soil and accounted for 68 and 37% of total C in the surface and lower soil layer, respectively, after 18 years. The C content of the particulate light fraction (PLF-C) was largest in the rainforest and smallest in the papaya plantation. The PLF-C accounted for 12–36% in the surface soil and 10–16% in the 5–15 cm layer. The size of the PLF was not only influenced by the quantity of C inputs, but also strongly reflected the quality of incoming litter. According to its δ 13C signature the large (> 100 μm) PLF was of younger age than the finer PLF or whole soil samples. The age of the 53–100 μm PLF was very close to that of stabilized organic matter as indicated by 13C data, its low C-to-N ratio (15–17:1) and its turnover time was about 30 y. The PLF appeared not to consist of one uniform pool and thus may have to be subdivided to be useful for modelling purposes (e.g. active, passive pools and charcoal). The contribution of PLF and above ground litter to total soil N mineralization (anaerobic incubation) was highest in the undisturbed rainforest ( 12 16 % for the PLF/litter, respectively, in the 0–2 cm layer), but much less in the other systems. However, mineralization of PLF from different sources was unpredictably altered by the density agent. Introducing D. ovalifolium into these pastures increased, significantly, the amounts of N in PLF, decreased the C-to-N ratio of PLF and tended to increase, the mineralization potential despite its high lignin and polyphenol content. The combination of δ 13C analysis and size/density separations, of surface samples in particular, allowed sensitive detection of changes in soil organic matter dynamics and soil fertility.

Land‐use and fertilization effects on P forms in two European soils: resin extraction and 31P‐NMR analysis

SummaryMacroporous anion‐exchange resin extraction and 31P‐NMR spectroscopy of dialysed NaOH extracts were used to investigate the effects of land use (Taubenberg, Bavaria: spruce forest, deciduous forest, permanent grass, arable) and fertilization (Askov, Denmark: unmanured, mineral fertilizer, animal manure) on forms of phosphorus in soil with emphasis on the potentially labile organic (Po) and inorganic (Pi pools. Carbon content ranged from 12.5–118.1 g kg−1 and total P (Pi) content from 511 to 2063 mg kg−1. For all soils, the C:Po ratios of SOM decreased in the order: whole soil, 150: 1–44:1; alkali extract, 57:1–41: 1; resin extract, 20:1–9:1; suggesting an increasing P functionality of the OM with increasing Po lability. Analysis of functional relation showed a close relation between resin Po and 31P‐NMR estimates for diester‐P including teichoic acid‐P, indicating that these species contributed significantly to the labile Po pool as determined by the resin method. The most marked effects of land‐use were an increase in Pi under grass and arable, a concurrent sequestration of Po and SOM under grass, and a depletion of Po under arable. The amount of resin Pj appeared to be a function primarily of fertilization, and amounted to around 100 mg kg−1 in the fertilized soils irrespective of the SOM content and P source. The forest soil and the unfertilized agricultural soil had much smaller resin Pj values. The soil under grass had the largest amounts in resin Po and diester‐P including teichoic acid‐P, indicating a rapid turnover of Po with build‐up of a large potentially labile, microbially derived Po pool. 31P NMR also showed large proportions of labile Po species in soils where microbial activity is restrained by acidity (Taubenberg spruce forest, phosphonates) or where highly microbially altered OM is relatively enriched (Taubenberg arable, diester‐P including teichoic acid‐P).We conclude that the resin used in this study isolates a structurally and functionally reasonably uniform pool of potentially labile soil Po.