bluuebunny/crossref_metadata_2025 huggingface dataset:
The extended hippocampal‐diencephalic memory system: Enriched housing promotes recovery of the flexible use of spatial representations after anterior thalamic lesions
Authors: Wolff Mathieu , Loukavenko Elena A. , Will Bruno E. , Dalrymple‐Alford John C.
Published: June 2008

The anterior thalamic (AT) nuclei constitute an important component of an extended hippocampal‐diencephalic system, and severe persisting memory deficits are normally found after AT damage. This study examined whether postoperative enrichment promotes the recovery of the flexible use of spatial representations in rats with AT lesions. After training to swim from a single constant start position to a submerged platform in a Morris water maze, rats with AT lesions that were housed in standard cages (AT‐Std) performed poorly when required to swim to the platform from novel start positions during probe trials. By contrast, rats with AT lesions but housed in enriched environments (AT‐Enr), like sham‐lesion rats, showed relatively little disruption when tested with novel start positions. AT‐Std rats also initially showed impaired acquisition of the task, whereas AT‐Enr rats learned at a similar rate to that of the Sham‐Std group. Beneficial effects of enrichment were replicated in the subsequent standard water maze procedure that used varying start positions throughout training to acquire a new platform location. Although it is clear that AT damage can severely disrupt episodic‐like memory processes, and appear to be a core part of the interlinked neural systems subserving episodic memory, the current findings strongly encourage study on the adaptive response of the brain to thalamic lesions and prospects for the development of rehabilitation programs in cases of anterograde amnesia associated with diencephalic injury. © 2008 Wiley‐Liss, Inc.
Transport and retention of Escherichia coli in a mixture of quartz, Al‐coated and Fe‐coated sands
Authors: Kim Song‐Bae , Park Seong‐Jik , Lee Chang‐Gu , Kim Hyon‐Chong
Published: June 2008

Transport and retention of Escherichia coli through the mixture of quartz, Al‐coated and Fe‐coated sands was examined using column experiments to investigate the effect of geochemical heterogeneity on bacteria transport. The first set of the experiments was performed in quartz, Al‐coated and Fe‐coated sand mixtures (coated sand: 0, 5, 10, 25, 50, 100%) to examine the influence of positively‐charged sand grains on bacteria transport. The second experiments were carried out to observe the impact of pH (range 6·74–8·21) on bacteria transport in the mixture of quartz 50% and Fe‐coated sand 50%. The third experiments were conducted to analyse the effect of ionic strength (0, 50, 100, 200 mM) on bacteria transport in the mixture of quartz 50% and Al‐coated sand 50%. The first experiments show that bacterial mass recoveries were in the range of 3·6–43·4%, decreasing nonlinearly as the content of Al‐ and Fe‐coated sands increased. In the second experiments, the bacterial mass recoveries were in the range of 35·5–79·2%, increasing linearly as the solution pH increased. In the third experiments, the mass recovery was 3·4% at 0 mM. As the ionic strength increased to 50mM, the mass recovery decreased to 0%. When the ionic strength increased further to 100 and 200 mM, no bacterial mass was recovered as in the case of 50 mM. It indicates that in the mixed medium of quartz 50% and Al‐coated sand 50% both positive (increment of bacterial adhesion) and negative (decrement) effects of ionic strength may be counterbalanced, minimizing the impact of ionic strength on the bacterial adhesion. This study helps to understand the role of metal oxides and solution chemistry in the transport of bacteria in geochemically heterogeneous media Copyright © 2008 John Wiley & Sons, Ltd.
Genetic and epigenetic inactivation of T‐cadherin in human hepatocellular carcinoma cells
Authors: Chan David W. , Lee Joyce M.F. , Chan Patrick C.Y. , Ng Irene O.L.
Published: June 2008

T‐cadherin is an atypical cadherin and growing evidence has indicated that T‐cadherin exerts tumor‐suppressive effects on cancers of epithelial cell type and also causes positive effects on tumor angiogenesis. Human hepatocellular carcinoma (HCC) is a hypervascular tumor and T‐cadherin has been shown to be overexpressed in intratumoral endothelial cells of HCCs. However, the expression status and functions of T‐cadherin in hepatocytes or HCC cells remain unclear. Here, we demonstrated that T‐cadherin was underexpressed in HCC cells (26.5%, 13/49 cases), but was frequently (77.6%, 38/49) overexpressed in intratumoral endothelial cells immunohistochemically. Semiquantitative RT‐PCR analysis also showed that the T‐cadherin gene was underexpressed in 7 of 11 HCC cell lines. Loss of heterozygosity analysis revealed that 32–38% of the 42 human HCC samples had allelic losses at this locus. Upon pharmacological treatment with demethylating agent 5‐aza‐2′‐deoxycytidine or histone deacetylase inhibitor trichostatin A, T‐cadherin promoter hypermethylation and/or histone deacetylation was frequently observed in HCC samples and cell lines. Functionally, enforced expression of T‐cadherin induced G2/M cell cycle arrest, reduced cell proliferation in low serum medium, suppressed anchorage‐independent growth in soft agar and increased sensitivity to TNFα‐mediated apoptosis in HCC cells. Intriguingly, we found that T‐cadherin significantly suppressed the activity of c‐Jun, a crucial oncoprotein constitutively activated in HCC cells. To conclude, T‐cadherin was differentially expressed in human HCCs. The underexpression of T‐cadherin in HCC cells suggests it may be another critical event in addition to T‐cadherin‐mediated angiogenesis during HCC development. © 2008 Wiley‐Liss, Inc.
A methodology for analyzing curvature in the developing brain from preterm to adult
Authors: Pienaar R. , Fischl B. , Caviness V. , Makris N. , Grant P. E.
Published: June 2008

The character and timing of gyral development is one manifestation of the complex orchestration of human brain development. The ability to quantify these changes would not only allow for deeper understanding of cortical development but also conceivably allow for improved detection of pathologies. This article describes a FreeSurfer‐based image‐processing analysis “pipeline” or methodology that inputs an MRI volume, corrects possible contrast defects, creates surface reconstructions, and outputs various curvature‐based function analyses. A technique of performing neonate reconstructions using FreeSurfer, which has not been possible previously because of inverted image contrast in premyelinated brains, is described. Once surfaces are reconstructed, the analysis component of the pipeline incorporates several surface‐based curvature functions found in literature (principle curvatures, Gaussian, mean curvature, “curvedness,” and Willmore Bending Energy). We consider the problem of analyzing curvatures from different sized brains by introducing a Gaussian‐curvature based variable‐radius filter. Segmented volume data are also analyzed for folding measures: a gyral folding index (gyrification‐white index GWI) and a gray‐white matter junction folding index (WMF). A very simple curvature‐based classifier is proposed that has the potential to discriminate between certain classes of subjects. We also present preliminary results of this curvature analysis pipeline on nine neonate subjects (30.4 weeks through 40.3 weeks Corrected Gestational Age), three children (2, 3, and 7 years), and three adults (33, 37, and 39 years). Initial results demonstrate that curvature measures and functions across our subjects peaked at term, with a gradual decline through early childhood and further decline continuing through to adults. We can also discriminate older neonates, children, and adults based on curvature analysis. Using a variable radius Gaussian‐curvature filter, we also observed that the per‐unit bending energy of neonate brain surfaces was also much higher than the children and adults. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 42–68, 2008
A fast spherical inflation method of the cerebral cortex by deformation of a simplex mesh on the polar coordinates
Authors: Kwon Min Jeong , Hahn Jooyoung , Park HyunWook
Published: June 2008

The convoluted shape of the cerebral cortex makes it difficult to analyze and visualize the neuronal activation area. One way of overcoming this problem is to use a spherical inflation method to draw a cerebral cortex on a spherical surface. The task of mapping the cortical surface on a sphere has several obstacles, namely, the overlap between the polygons of the surface, the heavy computation demand, and the geometric distortions inherent in the process. This article proposes a method of mapping the three‐dimensional (3D) cortical surface represented in a simplex mesh to a sphere surface, which does not have any overlap between the polygons and minimizes the geometric distortions as well as the computation time. The proposed method consists of the two steps of preprocessing and refinement. In the preprocessing step, the 3D cortical surface is mapped onto a sphere without any overlap between the polygons by iterative deformation. In the refinement step, the mapped surface is adjusted to minimize its linear distortion. The experimental results show the efficiency and performance of the proposed mapping method. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 9–16, 2008
New brain atlas—Mapping the human brain in vivo with 7.0 T MRI and comparison with postmortem histology: Will these images change modern medicine?
Authors: Cho Zang‐Hee , Kim Young‐Bo , Han Jae‐Yong , Min Hoon‐Ki , Kim Kyoung‐Nam , Choi Sang‐Han , Veklerov Eugene , Shepp Larry A.
Published: June 2008

Human brain imaging with magnetic resonance at 7.0 Tesla (T) can reveal the brain's architecture with resolution equivalent to that obtained from thin slices in vitro. In vivo images can provide tissue type identification with a greater clarity than that available in vitro without special stains. The coil design is an 8 or 12 channel phased array antenna tuned for 7.0T. The individual coils are arranged 8 or 12 loops in a “crown” configuration. Image acquisition is 6 minutes for 15 slices of 2 mm thickness with in‐plane resolution of 0.25 mm using a gradient echo pulse sequence. While others have achieved good resolution in human brain imaging, this paper demonstrates a pulse sequence with a specialized radiofrequency coil that achieves an uniformity and resolution not shown in previous studies at 7.0T. Our new images demonstrate very fine details of the midbrain, brainstem, and hippocampal area that have not been previously achieved in living human subjects. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 2–8, 2008
Differential transient MEG and fMRI responses to visual stimulation onset rate
Authors: Tuan August S. , Birn Rasmus M. , Bandettini Peter A. , Boynton Geoffrey M.
Published: June 2008

While recent analysis of functional magnetic resonance imaging (fMRI) data utilize a generalized nonlinear convolution model (e.g., dynamic causal modeling), most conventional analyses of local responses utilize a linear convolution model (e.g., the general linear model). These models assume a linear relationship between the blood oxygenated level dependent (BOLD) signal and the underlying neuronal response. While previous studies have shown that this “neurovascular coupling” process is approximately linear, short stimulus durations are known to produce a larger fMRI response than expected from a linear system. This divergence from linearity between the stimulus time‐course and BOLD signal could be caused by neuronal onset and offset transients, rather than a nonlinearity in the hemodynamics related to BOLD contrast. We tested this hypothesis by measuring MEG and fMRI responses to stimuli with ramped contrast onsets and offsets in place of abrupt transitions. MEG results show that the ramp successfully reduced the transient onset of neural activity. However, the nonlinearity in the fMRI response, while also reduced, remained. Predictions of fMRI responses from MEG signals show a weaker nonlinearity than observed in the actual fMRI data. These results suggest that the fMRI BOLD nonlinearity seen with short duration stimuli is not solely due to transient neuronal activity. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 17–28, 2008
Design of irrigation water supply systems using the Q–C feasibility domain concept: I. Introduction and theory
Authors: Sinai Gideon , Dalins Ben‐Zion , Cohen Daniel , Shamir Uri
Published: June 2008

The Q–C Feasibility Domain (QCFD) was defined and proposed as a tool for design of multiquality irrigation water supply systems. It determines all feasible combinations of water discharge and water quality, and can be represented by a point, a line, or an area in a diagram of water discharge versus solute flow rate (a Q–J diagram). The shape of the QCFD is the result of dilution of two or more flows from sources of different water quality. (assuming conservative substances) Several types of QCFDs were analyzed at sources, inner nodes of a network, and of consumer outlets. The effect of water discharge constraints (due to flow limitations in the network) on the QCFDs was formulated and analyzed. Computation of QCFDs of dilution junctions by vector addition of their inflows was described. The method was extended numerically to nonlinear mixing due to dependence of water salinity. Use of this method enables computation of QCFDs for inner nodes in networks, including dilution junctions. The effect of network topology and flow direction was discussed. Application and demonstration will follow in the next paper in this series. Copyright © 2008 John Wiley & Sons, Ltd.
Tail morphology in the Western Diamond‐backed rattlesnake, Crotalus atrox
Authors: Savitzky Alan H. , Moon Brad R.
Published: June 2008

The shaker muscles in the tails of rattlesnakes are used to shake the rattle at very high frequencies. These muscles are physiologically specialized for sustaining high‐frequency contractions. The tail skeleton is modified to support the enlarged shaker muscles, and the muscles have major anatomical modifications when compared with the trunk muscles and with the tail muscles of colubrid snakes. The shaker muscles have been known for many years to consist of three large groups of muscles on each side of the tail. However, the identities of these muscles and their serial homologies with the trunk muscles were not previously known. In this study, we used dissection and magnetic resonance imaging of the tail in the Western Diamond‐backed Rattlesnake, Crotalus atrox, to determine that the three largest muscles that shake the rattle are the M. longissimus dorsi, the M. iliocostalis, and the M. supracostalis lateralis. The architecture of these muscles differs from their serial homologs in the trunk. In addition, the rattlesnake tail also contains three small muscles. The M. semispinalis‐spinalis occurs in the tail, where it is a thin, nonvibratory, postural muscle that extends laterally along the neural spines. An additional muscle, which derives from fusion of the M. interarticularis inferior and M. levator costae, shares segmental insertions with the M. longissimus dorsi and M. iliocostalis. Several small, deep ventral muscles probably represent the Mm. costovertebrocostalis, intercostalis series, and transversohypapophyseus. The architectural rearrangements in the tail skeleton and shaker muscles, compared with the trunk muscles, probably relate to their roles in stabilizing the muscular part of the tail and to shaking the rattle at the tip of the tail. Based on comparisons with the tail muscles of a colubrid snake described in the literature, the derived tail muscle anatomy in rattlesnakes evolved either in the pitvipers or within the rattlesnakes. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Morphology and histology of male and female reproductive systems in the inseminating species Scoloplax distolothrix (Ostariophysi: Siluriformes: Scoloplacidae)
Authors: Spadella Maria Angélica , Oliveira Claudio , Quagio‐Grassiotto Irani
Published: June 2008

The morphology and histology of male and female reproductive systems were examined in Scoloplax distolothrix. Internal insemination was documented in this species by the presence of sperm within the ovaries. Mature males and females have elongated genital papillae, exhibiting a tubular shape in males and a plain heart‐shape with two median protuberances in females. The testes are two elongated structures that converge ventrally, under the intestine, towards the genital papilla. They are joined at the caudal end, forming an ovoid single chamber for sperm storage. Secretory regions were not observed. In the lumen of the testicular tubules, spermatozoa can be tightly packed along their lengths, but do not constitute a spermatozeugmata. The lumen of the sperm storage chamber and spermatic duct are filled with free spermatozoa without the accompanying secretions. The ovaries are bird‐wing shaped, saccular structures that converge ventrally under the intestine, towards the genital papilla. They are joined at the caudal end, forming a tubular chamber possibly destined for oocyte storage. An oviduct with an irregular outline connects the chamber to the tubular region of the genital papilla. No distinct sperm storage structure was found in the ovaries. The unique male and female genital papillae suggest that these structures are associated with the reproductive mode in scoloplacids, representing evidence for insemination. The occurrence of free spermatozoa, without the accompanying secretions and not arranged in a spermatozeugmata can be associated with the presence of a tubular male genital papilla for sperm transfer to the female genital tract. This reinforces the idea that sperm packets are not necessary for all inseminating species. The male reproductive system in scoloplacids is very different from that in auchenipterids, a second catfish family with insemination, which indicates that the occurrence of insemination is not connected to the internal morphology of reproductive organs. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Cardiovascular system of anomuran crabs, genus Lopholithodes
Authors: McGaw Iain J. , Duff Stefanie D.
Published: June 2008

The cardiovascular systems of Puget Sound king crabs, Lopholithodes mandtii, and brown box crabs, Lopholithodes foraminatus, were mapped using corrosion casting techniques. Both species have a similar external morphology and a very similar cardiovascular system. Seven arteries (five arterial systems) arise from the heart. The small anterior aorta exits from the anterior surface of the heart and supplies hemolymph to the eyestalks and brain region. The pathway of the two sets of paired arteries, the anterolateral arteries and hepatic arteries, is close, and they intertwine with one another during their initial course. The anterolateral arteries exit from the anterior dorsal surface of the heart and supply hemolymph to the hypodermis, cardiac stomach, antennal gland, and mandibular muscles, whereas the hepatic arteries branch profusely within the hepatopancreas. The lithodids are believed to have evolved from hermit crab ancestors; indicative of these evolutionary origins the posterior aorta is well developed and supplies hemolymph to the large abdomen and the gonads. Exiting from the ventral surface of the heart, the sternal artery is the largest in the system. It branches to supply the mouthparts, chelae, and pereiopods. The differing arrangement of this vessel compared with that of the pagurid anomurans is due to the more carcinized (crab‐like) morphological features of the lithodid anomurans. The arrangement of vessels supplying the gills is different compared with that of brachyuran crabs; the infrabranchial sinus joins to the afferent gill vessels at their midpoint, rather than along the ventral edge. In general, the circulatory system of the lithodid crabs is somewhat simpler than that of brachyuran crabs, with fewer branching capillary‐like networks. Nevertheless, it is still very complex. In accordance with anatomical descriptions of blue crabs and cancrid crabs it would also seem appropriate to classify the lithodid circulatory system as one that is incompletely closed. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
The ultrastructure of the spermathecae in the Collembola Symphypleona (Hexapoda)
Authors: Dallai Romano , Zizzari Zaira Valentina , Fanciulli Pietro Paolo
Published: June 2008

The fine structure of the paired spermathecae of two Symphypleona Collembola, Sminthurus viridis and Allacma fusca, was studied. The spermathecal epithelium is rich in pigment granules, while secretory organelles are scarce, consisting of a few mitochondria and microtubules, scattered cisterns of endoplasmic reticulum and Golgi systems. Small isolated secretory granules are visible in the apical cell region, where irregular microvilli are present. Beneath the epithelium, large cells rich in endoplasmic reticulum and Golgi systems are present; they are separated from the epithelial cells by a thin basal lamina. The epithelium is lined by a thin cuticle, which forms thin extensions at the beginning of the spermathecal duct. At this level, muscle fibers are visible. The spermathecal lumen is filled with many spermatozoa. At molting, the spermathecal epithelial cells detach from the cuticle and a large electron‐transparent space is evident between the cytoplasm and the cuticle. The cytoplasm has few pigment granules and the spermathecal lumen contains degenerating spermatozoa. After 3 days, the spermathecal epithelium regains its usual appearance and the spermathecal lumen is empty. The two species of Collembola Symphypleona do not have accessory glands. Compared with the Arthropleona Orchesella villosa, which has a single spermatheca and two accessory glands (Dallai et al. 2008 J Morphol 269:464–478), a great difference has occurred in the organization of the female genital system of these species. The results are discussed in light of the implications for reproductive behavior and egg protection in Symphypleona. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Extraction of mobile element fractions in forest soils using ammonium nitrate and ammonium chloride
Authors: Schöning Alexander , Brümmer Gerhard W.
Published: June 2008

The extraction of earth alkaline and alkali metals (Ca, Mg, K, Na), heavy metals (Mn, Fe, Cu, Zn, Cd, Pb) and Al by 1 M NH4NO3 and 0.5 M NH4Cl was compared for soil samples (texture: silt loam, clay loam) with a wide range of pH(CaCl2) and organic carbon (OC) from a forest area in W Germany. For each of these elements, close and highly significant correlations could be observed between the results from both methods in organic and mineral soil horizons. The contents of the base cations were almost convertible one‐to‐one. However, for all heavy metals NH4Cl extracted clearly larger amounts, which was mainly due to their tendency to form soluble chloro complexes with chloride ions from the NH4Cl solution. This tendency is very distinct in the case of Cd, Pb, and Fe, but also influences the results of Mn and Zn. In the case of Cd and Mn, and to a lower degree also in the case of Pb, Fe, and Zn, the effect of the chloro complexes shows a significant pH dependency. Especially for Cd, but also for Pb, Fe, Mn, Zn, the agreement between both methods increased, when pH(CaCl2) values and/or contents of OC were taken into account. In comparison to NH4Cl, NH4NO3 proved to be chemically less reactive and, thus, more suitable for the extraction of comparable fractions of mobile heavy metals. Since both methods lead to similar and closely correlated results with regard to base cations and Al, the use of NH4NO3 is also recommended for the extraction of mobile/exchangeable alkali, earth alkaline, and Al ions in soils and for the estimation of their contribution to the effective cation‐exchange capacity (CEC). Consequently, we suggest to determine the mobile/exchangeable fraction of all elements using the NH4NO3 method. However, the applicability of the NH4NO3 method to other soils still needs to be investigated.
Trends in grain yields and soil organic C in a long‐term fertilization experiment in the China Loess Plateau
Authors: Fan Tinglu , Xu Minggang , Song Shangyou , Zhou Guangye , Ding Linping
Published: June 2008

Changes in grain yields and soil organic carbon (SOC) from a 26 y dryland fertilization trial in Pingliang, Gansu, China, were recorded. Cumulative C inputs from straw and root and manure for fertilizer treatments were estimated. Mean wheat (Triticum aestivum L.) yields for the 18 y ranged from 1.72 t ha–1 for the unfertilized plots (CK) to 4.65 t ha–1 for the plots that received manure (M) annually with inorganic N and P fertilizers (MNP). Corn (Zea mays L.) yields for the 6 y averaged 2.43 and 5.35 t ha–1 in the same treatments. Yields declined with year except in the CK for wheat. Wheat yields for N only declined with time by 117.8 kg ha–1 y–1 that was the highest decrease among all treatments, and that for NP declined by 84.7 kg ha–1 y–1, similar to the declines of 77.4 kg ha–1 y–1 for the treatment receiving straw and N annually and P every second year (SNP). Likewise, the corn yields declined highly for all treatments, and the declined amounts ranged from 108 to 258 kg ha–1 y–1 which was much higher than in wheat. These declined yields were mostly linked to both gradual dry weather and nutrients depletion of the soil. The N only resulted in both P and K deficiency in the soil, and soil N and K negative balances in the NP and MNP were obvious. Soil organic carbon (SOC) in the 0–20 cm soil layer increased with time except in the CK and N treatments, in which SOC remained almost stable. In the MNP and M treatments, 24.7% and 24.0% of the amount of cumulative C input from organic sources remained in the soil as SOC, but 13.7% of the C input from straw and root in the SNP, suggesting manure is more effective in building soil C than straw. Across the 26 y cropping and fertilization, annual soil‐C sequestration rates ranged from 0.014 t C ha–1 y–1 for the CK to 0.372 t C ha–1 y–1 for the MNP. We found a strong linear relationship (R2 = 0.74, p = 0.025) between SOC sequestration and cumulative C input, with C conversion–to–SOC rate of 16.9%, suggesting these dryland soils have not reached an upper limit of C sequestration.
Comparison of different methods for the measurement of ammonia volatilization after urea application in Henan Province, China
Authors: Pacholski Andreas , Cai Gui‐Xin , Fan Xiao‐Hui , Ding Hong , Chen Deli , Nieder Rolf , Roelcke Marco
Published: June 2008

Ammonia losses following urea fertilization of maize and winter wheat were determined in field trials carried out at Fengqiu Experimental Station in the North China Plain in 1998 and 1999. Four experiments were carried out using two simplified micrometeorological integrated horizontal flux methods [IHF(L) and IHF(S)], a chamber method (calibrated Dräger‐Tube Method DTM) and the 15N‐balance method using 15N‐labeled urea. The IHF(L) was taken as the reference method. Both IHF methods showed good agreement in one experiment only, while the IHF(S) overestimated as well as underestimated cumulative ammonia losses compared to IHF(L) in the other experiments (deviation ranged from 12.5% to 64% based on cumulative ammonia losses). Regression analysis of the fluxes showed that in particular different sensitivities of the samplers to wind speed accounted for the discrepancies observed. The IHF(L) and the DTM flux curves were very similar in three experiments, while the values obtained with DTM considerably deviated from IHF(L) results in one experiment. A comparison with apparent fertilizer‐N losses determined by the 15N‐labeling approach showed that ammonia volatilization was the major pathway of fertilizer‐N loss in this study.
Use of mid‐infrared spectroscopy in the diffuse‐reflectance mode for the prediction of the composition of organic matter in soil and litter
Authors: Ludwig Bernard , Nitschke Renate , Terhoeven‐Urselmans Thomas , Michel Kerstin , Flessa Heiner
Published: June 2008

Mid‐infrared spectroscopy (MIRS) is assumed to be superior to near‐infrared spectroscopy (NIRS) for the prediction of soil constituents, but its usefulness is still not sufficiently explored. The objective of this study was to evaluate the ability of MIRS to predict the chemical and biological properties of organic matter in soils and litter. Reflectance spectra of the mid‐infrared region including part of the near‐infrared region (7000–400 cm–1) were recorded for 56 soil and litter samples from agricultural and forest sites. Spectra were used to predict general and biological characteristics of the samples as well as the C composition which was measured by 13C CPMAS‐NMR spectroscopy. A partial least‐square method and cross‐validation were used to develop equations for the different constituents over selected spectra ranges after several mathematical treatments of the spectra. Mid‐infrared spectroscopy predicted well the C : N ratio: the modeling efficiency EF was 0.95, the regression coefficient (a) of a linear regression (measured against predicted values) was 1.0, and the correlation coefficient (r) was 0.98. Satisfactorily (EF ≥ 0.70, 0.8 ≤ a ≤ 1.2, r ≥ 0.80) assessed were the contents of C, N, and lignin, the production of dissolved organic carbon, and the contents of carbonyl C, aromatic C, O‐alkyl C, and alkyl C. However, the N mineralization rate, the microbial biomass and the alkyl–to–aromatic C ratio were predicted less satisfactorily (EF < 0.70). Limiting the sample set to mineral soils did generally not result in improved predictions. The good and satisfactory predictions reported above indicate a marked usefulness of MIRS in the assessment of chemical characteristics of soils and litter, but the accuracies of the MIRS predictions in the diffuse‐reflectance mode were generally not superior to those of NIRS.
Challenges of species distribution modeling belowground
Authors: Schröder Boris
Published: June 2008

Understanding the relationship between soil biodiversity, habitat, and function is one of the main issues of soil‐ecological research. The description of spatiotemporal distributions of soil organisms at relevant scales and in relation to their activity is a prerequisite to understand and quantify the factors that control soil functions. Species distribution models can help to explain the functional relationships between organisms and their habitat by estimating occurrence probabilities from spatial‐distribution data and environmental predictors for single species or species groups. Here, I present a brief overview of recent developments in species distribution models and illustrate this tool with a case study using a carabid beetle species in a small‐scale highly heterogeneously structured environment. In the light of the peculiarities of soil organisms and habitat, several implications and challenges of species distribution models are discussed referencing some instructive studies on the spatial distribution of soil organisms over a range of spatiotemporal scales. The most important challenges of species distribution models for soil organisms comprise the spatiotemporal heterogeneity of soil habitat on a hierarchy of nested scales; the overwhelming diversity of soil organisms with largely unknown life histories, habitat requirements, and dispersal characteristics; taxonomic and technical limitations regarding sampling and measurements; feedbacks between soil biota and their habitat. There is a clear theoretical and practical basis for considering both environmental and geographic drivers of species distributions in soil studies, and for doing so across multiple scales. This would yield a habitat‐based soil ecology by combining the spatially explicit approach proposed by Ettema and Wardle (2002) with the niche‐based approach of species distribution modeling.
A spatial approach to soil‐ecological experimentation at landscape scale
Authors: Joschko Monika , Oehley Jörg , Gebbers Robin , Wiemer Martina , Timmer Jens , Fox Catherine A.
Published: June 2008

The upscaling of soil‐ecological processes to larger landscape units represents a special challenge to soil ecology. Results from micro‐ or mesocosms cannot easily be transferred to other scales because effects are often scale‐dependent. In this context, field experiments which take into account the heterogeneity of the landscape may be promising. Therefore, we carried out an experiment based on a transect study in the agrolandscape of NE Germany on heterogeneous sandy soil in which the feeding activity of the soil‐organism community was assessed by means of the bait‐lamina test at each of the 101 transect locations. At every 4th position, prior to the measurement the soil biota were stimulated by a treatment consisting of adding easily available C and water to the soil. Our aim was to test whether this kind of spatial approach enables to separate effects induced by treatments from landscape effects. The results showed a highly variable feeding activity along the transect after 4 weeks. Despite this variability, a basic trend could be identified which was related to a landscape factor,i.e., the relief. On upper‐slope positions, the feeding activity tended to be less in comparison to positions down‐slope. At every 4th position of the transect, the stimulating effect of the substrate and water addition could be clearly detected and quantified with spectral and cross‐spectral analysis. It is concluded that effects of treatments in heterogeneous landscapes may be distinguished from site effects when the signal‐to‐noise ratio is high and soil and treatment effects on the variable of interest are sufficiently different from one another. In a heterogeneous landscape with gradients of site properties, a treatment based on the frequency domain and applied in regular intervals can be distinguished with spectral analysis techniques.
Plant‐available nitrogen in the soil: Relationships between pre‐plant and pre‐sidedress nitrate tests for corn production
Authors: Ma Bao Luo , Wu Tian‐Yun
Published: June 2008

Corn (Zea mays L.) producers in the rainfed regions sometimes sidedress fertilizer N according to pre‐plant–nitrate test (PPNT) results based on the assumption that there is a linear relationship between pre‐sidedress nitrate test (PSNT) and the PPNT. There has been no report on such relationship in Ontario (Canada) and elsewhere in the nonirrigated corn‐growing regions. A field study was conducted near Ottawa, Canada for 7 y to (1) determine changes in soil available N from pre‐planting to shortly after the sidedress stage (late June) for corn and (2) establish a quantitative relationship between PPNT and PSNT. In each year, soil samples from fields of three to four plot experiments with different cropping histories, soil textures, and management levels, taken at 7 to 10 d intervals, and from on‐farm trials taken at pre‐planting and pre‐sidedress, were extracted with 2 M KCl. The concentrations of NO$ _3^- $‐N were determined colorimetrically. It was found that soil NO$ _3^- $‐N concentration of PSNT was a linear function of PPNT with an average slope of 1.7. However, the slope of the regression equations differed dramatically among cropping sequences, and to a lesser extent, soil textures. The NO$ _3^- $‐N concentration after planting to pre‐sidedress was influenced by air temperature and precipitation during this period of time. Both PPNT and PSNT positively correlated with corn‐grain yield. Our data suggest that cautions must be taken when deciding the rate of fertilizer N for sidedress application to corn based on PPNT test, especially under more humid northern climate conditions.
Total soil heavy‐metal concentrations and mobile fractions after 10 years of biowaste‐compost fertilization
Authors: Erhart Eva , Hartl Wilfried , Putz Berta
Published: June 2008

The accumulation of heavy metals (HMs) in soils is the most often cited potential risk of compost application. As the ecological effects of metals are related to mobile fractions rather than to total concentrations in the soil, we measured the total (aqua regia–extractable) HM concentrations, the readily available water‐soluble and the potentially bioavailable LiCl‐extractable fraction of soil HMs in a field experiment after 10 y with total applications of 95, 175, and 255 t ha–1 biowaste compost (fresh matter). Total soil concentrations of Cd, Cr, Cu, Ni, and Pb in the compost treatments were not significantly higher than in the unfertilized control. Total Zn concentrations increased in the treatment with the highest application rate, as expected from the calculation of the Zn load in the composts. In the mobile fractions, as measured in soil saturation extract and LiCl extract, Cd and Pb were not detectable. Concentrations of Cr, Ni, and Zn were in the range published for unpolluted soils in other studies and did not show any differences according to treatment. Easily exchangeable Cu (in LiCl extract) was increased with compost fertilization, most probably due to complexation with low‐molecular organic complexants. Except for Cd and Zn, the results of the mobile HM fractions in the soil were in good agreement with plant HM concentrations. In conclusion, fertilization with high‐quality biowaste compost at such rates and after 10 y of application gives no cause for concern with regard to both total HM concentrations and available HM fractions.
Potassium efficiency of safflower (Carthamus tinctorius L.) and sunflower (Helianthus annuus L.)
Authors: Gerendás Jóska , Abbadi Jehad , Sattelmacher Burkhard
Published: June 2008

The oil crop safflower may have a certain production potential under low‐input conditions (organic farming, developing countries), where the putatively low nutrient requirement is highly welcomed. However, current knowledge regarding the nutrient use efficiency of safflower as compared to similar oil crops is limited. It was thus the aim of this study to determine the potassium (K) use efficiency of safflower (Carthamus tinctorius L.) as compared to sunflower (Helianthus annuus L.). Safflower and sunflower were cultivated with increasing K supply in a mixture of equal volumes of sand, nutrient‐poor limed soil, and perlite in 5 L Mitscherlich pots. Both species responded strongly to increasing K supply with respect to growth and yield. Safflower out‐yielded sunflower at low K supply, while at high K level, the opposite was observed. Both species accumulated similar amounts of K in shoots at low K supply. Only at extremely low K supply, safflower took up more K than sunflower. However, achene yield of sunflower exceeded that of safflower at optimal and high K supply. Safflower utilized absorbed K more efficiently than sunflower to produce achene yield at suboptimal K supply in terms of both efficiency ratio and utilization index. The efficiency of a crop to use supplied or accumulated K for dry‐matter and achene production was interpreted in terms of Michaelis‐Menten kinetics, specifically addressing the shape of the yield response curve. Indeed, the efficiency of safflower to use K for growth and yield, analogue to a low Km in enzyme kinetics, was higher than in sunflower, while the K supply or K accumulation required to initiate yield formation in safflower was significantly lower. Similarly, safflower had a lower external K requirement for achene yield than sunflower at low and optimal K supplies. It can be concluded that safflower represents a low‐input crop and outperforms sunflower on soils low in available K. The data analysis also reveals that using just one efficiency indicator is usually not sufficient to adequately describe the K efficiency of the crop under consideration.
Influence of nitrogen and weed management on the productivity of upland rice
Authors: Singh Chandra Vir , Ghosh Bidhan Chandra , Mittra Bishwa Nath , Singh Rama Kant
Published: June 2008

Nitrogen and weeds are two important factors that influence the productivity of rainfed upland rice (Oryza sativa L.) in tropical Asia. A low recovery of applied fertilizer N in rainfed uplands is generally associated with high nitrate leaching losses and weed interferences. Field experiments were conducted during the wet seasons of 2002 and 2003 at the research farm of Central Rainfed Upland Rice Research Station, Hazaribag, Jharkhand, India, to determine the response of upland rice to nitrogen applied at 60 kg N ha–1 as different forms of urea (single pre‐plant application of controlled‐release urea, single pre‐plant application of urea supergranules, and split application of prilled urea with or without basal N) against no N application under three weed‐control regimes (unweeded, pre‐emergence application of butachlor at 1.5 kg a.i. ha–1 supplemented with one single hand weeding or two hand weedings). The response of rice to applied N varied greatly among the three weed‐control regimes. Across the different N treatments, the application of 60 kg N ha–1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha–1 in unweeded treatments, whereas yields increased by 1.07 Mg ha–1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha–1 with two hand weedings. Among the weed‐control measures, hand weeding twice produced highest grain yield in both years. The comparison of different forms of urea showed that a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha–1 compared to 1.32 and 1.30 Mg ha–1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively. The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea, suggesting that this N form is particularly beneficial for upland‐rice cultivation under variable rainfall conditions, provided weeds are controlled.
Nanofabricated periodic arrays of silver elliptical discs as SERS substrates
Authors: Oran Jenny M. , Hinde Robert J. , Abu Hatab Nahla , Retterer Scott T. , Sepaniak Michael J.
Published: June 2008

Signal enhancement observed in surface‐enhanced Raman spectroscopy (SERS) is attributable to the presence of noble‐metal nanostructures on substrate surfaces. The rational development of SERS‐active substrates depends critically on the homogeneity and intensity of surface plasmon resonances, properties that are strongly dependent on both the morphology and dielectric properties of the metals and composite materials making up the SERS substrates. Enhancement can be controlled by the shape, size, and spacing of metallic nanoparticles. Previous studies in our group have shown that arrays of elliptical nanodiscs have promising geometries for this purpose. Using electron beam lithography (EBL), we fabricate close‐packed arrays of these discs with lateral dimensions ranging from 300:50 to 300:300 nm (long axis : short axis). The arrays are composed of a negative photoresist that, once the lithography process is complete, are coated with a noble metal through physical vapor deposition (PVD). In this work, optimum thickness and deposition rate of noble metal are determined for these substrates. The lithographically produced nanopatterns are studied by Raman spectroscopy to examine the effect of altering the elliptical aspect ratio on SERS activity, while scanning electron microscopy (SEM) is used to examine pattern surfaces post lithographic development and post noble‐metal deposition. Atomic force microscopy (AFM) is used to inspect the roughness of substrate surfaces. Reproducibility between different arrays of the same pattern ranges from 12 to 28%. Homogeneity of our uniform‐morphology EBL/PVD‐fabricated substrates is examined and compared to our random‐morphology polymer nanocomposite substrates. Using rhodamine 6G as an analyte, an increase in SERS signal is noted as the aspect ratio of ellipses goes from 6:1 to 6:6. Our experimental data, in terms of trends in SERS activity, correlate with trends in field enhancements calculated using a simple electrostatic model and with the magnitude of the broad red‐shifted spectral continuum observed for the substrates. Copyright © 2008 John Wiley & Sons, Ltd.
Thermal treatments to partially pre‐cook and improve the shelf‐life of whole pearl millet flour
Authors: Nantanga Komeine KM , Seetharaman Koushik , de Kock Henriette L , Taylor John RN
Published: June 2008

BACKGROUND: Pearl millet flour is highly susceptible to rancidity during storage. Urbanization has created a demand for pearl millet flour with longer shelf‐life and short cooking time. To try to prevent rancidity and pre‐cook the flour, pearl millet grain was subjected to the thermal treatments of toasting, boiling, and toasting then boiling.

RESULTS: Fat acidity of flour from the untreated grain increased from 0.11 to 3.73 g KOH kg−1 during three months' storage, whereas the wet thermally treated samples showed no significant increase (P > 0.05). Peroxide and conjugated diene values of wet thermally treated samples increased substantially, whereas those of flour from untreated grain did not, indicating less formation of rancid final oxidation products in the wet thermally treated samples. Starch degree of cook of the wet thermally treated samples was two times higher than the other treatments. Descriptive sensory evaluation revealed that porridges of flour from untreated grain were associated with hydrolytic rancidity, whereas those of flours from thermally treated grains were not. Consumers showed a preference for the porridges prepared from flour of boiled as well as toasted grain.

CONCLUSION: Thermal treatments can be applied to extend whole pearl millet flour shelf‐life, and the treatment of boiling can be used to produce pearl millet flour that cooks more quickly. Copyright © 2008 Society of Chemical Industry
Fatty acid composition of advanced olive selections obtained by crossbreeding
Authors: León Lorenzo , De la Rosa Raúl , Gracia Aurelio , Barranco Diego , Rallo Luis
Published: June 2008

BACKGROUND: An olive‐breeding programme aimed at obtaining new cultivars for olive oil production was initiated in Spain in 1991, with oil quality being considered one of the most important objectives. In this study the oil fatty acid composition of 15 advanced olive selections coming from crosses between ‘Arbequina’, ‘Frantoio’ and ‘Picual’ cultivars was evaluated.

RESULTS: A strong genetic effect and significant differences between genotypes were obtained for all fatty acids and ratios evaluated. The results allowed the classification of genotypes into four groups according to their fatty acid composition, with the percentages of C18:1, C18:2 and saturated fatty acids being the main contributors to the total variation. The relationship between the results of the initial seedling population and those of the advanced selections indicated that an efficient selection for fatty acid composition could be carried out by considering only a single year of evaluation at the seedling stage.

CONCLUSION: A quite different fatty acid composition in the oil of 15 advanced selections and their three genitors was obtained. These results suggest that new olive cultivars with fatty acid composition fulfilling consumer and market demands could be obtained through crossbreeding in the future. Copyright © 2008 Society of Chemical Industry
A confirmatory factor analysis of the acute stress disorder interview
Authors: Brooks Robert , Silove Derrick , Bryant Richard , O'Donnell Meaghan , Creamer Mark , McFarlane Alexander
Published: June 2008

Acute stress disorder (ASD) was introduced in 1994 to describe posttraumatic stress reactions that occur in the initial month after trauma exposure. Although it comprises the distinct symptom clusters of dissociation, reexperiencing, avoidance, and arousal, there have been no confirmatory factor analyses of the construct. In this study, 587 individuals admitted to five major hospitals after traumatic injury were administered the Acute Stress Disorder Interview. Forty‐four participants met criteria for ASD. Confirmatory factor analysis based on the four symptom clusters described the Acute Stress Disorder Interview responses. These data provide the first confirmatory factor analysis of the ASD symptoms, and are discussed in terms of the 4‐factor models repeatedly found in samples of chronic posttraumatic stress disorder.