Schiller International University

Abstract We summarize progress with respect to (1) different approaches to isolate, extract, and quantify organo‐mineral compounds from soils, (2) types of mineral surfaces and associated interactions, (3) the distribution and function of soil biota at organo‐mineral surfaces, (4) the distribution and content of organo‐mineral associations, and (5) the factors controlling the turnover of organic matter (OM) in organo‐mineral associations from temperate soils. Physical fractionation achieves a rough separation between plant residues and mineral‐associated OM, which makes density or particle‐size fractionation a useful pretreatment for further differentiation of functional fractions. A part of the OM in organo‐mineral associations resists different chemical treatments, but the data obtained cannot readily be compared among each other, and more research is necessary on the processes underlying resistance to treatments for certain OM components. Studies using physical‐fractionation procedures followed by soil‐microbiological analyses revealed that organo‐mineral associations spatially isolate C sources from soil biota, making quantity and quality of OM in microhabitats an important factor controlling community composition. The distribution and activity of soil microorganisms at organo‐mineral surfaces can additionally be modified by faunal activities. Composition of OM in organo‐mineral associations is highly variable, with loamy soils having generally a higher contribution of polysaccharides, whereas mineral‐associated OM in sandy soils is often more aliphatic. Though highly reactive towards Fe oxide surfaces, lignin and phenolic components are usually depleted in organo‐mineral associations. Charred OM associated with the mineral surface contributes to a higher aromaticity in heavy fractions. The relative proportion of OC bound in organo‐mineral fractions increases with soil depth. Likewise does the strength of the bonding. Organic molecules sorbed to the mineral surfaces or precipitated by Al are effectively stabilized, indicated by reduced susceptibility towards oxidative attack, higher thermal stability, and lower bioavailability. At higher surface loading, organic C is much better bioavailable, also indicated by little 14 C age. In the subsurface horizons of the soils investigated in this study, Fe oxides seem to be the most important sorbents, whereas phyllosilicate surfaces may be comparatively more important in topsoils. Specific surface area of soil minerals is not always a good predictor for C‐stabilization potentials because surface coverage is discontinuous. Recalcitrance and accessibility/aggregation seem to determine the turnover dynamics in fast and intermediate cycling OM pools, but for long‐term OC preservation the interactions with mineral surfaces, and especially with Fe oxide surfaces, are a major control in all soils investigated here.

The influence of a simple semiempirical van der Waals (vdW) correction on the description of dispersive, covalent, and ionic bonds within density functional theory is studied. The correction is based on the asymptotic London form of dispersive forces and a damping function for each pair of atoms. It thus depends solely on the properties of the two atoms irrespective of their environment and is numerically very efficient. The correction is tested in comparison with results obtained using the generalized gradient approximation or the local density approximation for exchange and correlation. The results are also compared with reference values from experiment or quantum chemistry methods. In order to probe the universality and transferability of the semiempirical vdW correction, a range of solids and molecular systems with covalent, heteropolar, and vdW bonds are studied.

We report the observation of optical Bloch oscillations in waveguide arrays. The required linear variation of the propagation constant across the thermo-optic polymer array was obtained by applying a temperature gradient. Bloch oscillations manifesting themselves as transverse oscillations of the propagating light beam can be attributed to the existence of localized states (Wannier-Stark states) with equidistant eigenvalue spacing (Wannier-Stark ladder). The period and amplitude of the oscillations can be controlled by varying the temperature gradient.

Executive Overview In a recent book, Pay without Performance: The Unfulfilled Promise of Executive Compensation, Bebchuk and Fried critique existing executive pay arrangements and the corporate governance processes that produce them. They also put forward proposals for improving both executive pay and corporate governance. This paper provides an overview of the main elements of their critique and proposals. The authors show that, under current legal arrangements, boards cannot be expected to contract at arm's length with the executives whose pay they set. They discuss how managers' influence can explain many features of the executive compensation landscape, including ones that researchers subscribing to the arm's-length contracting view have long considered as puzzling. The authors also explain how managerial influence can lead to inefficient arrangements that generate weak or even perverse incentives, as well as to arrangements that make the amount and performance-insensitivity of pay less transparent. Finally, they outline proposals for improving the transparency of executive pay, the connection between pay and performance, and the accountability of corporate boards.

Markus and Kitayama's (1991) theory of independent and interdependent self-construals had a major influence on social, personality, and developmental psychology by highlighting the role of culture in psychological processes. However, research has relied excessively on contrasts between North American and East Asian samples, and commonly used self-report measures of independence and interdependence frequently fail to show predicted cultural differences. We revisited the conceptualization and measurement of independent and interdependent self-construals in 2 large-scale multinational surveys, using improved methods for cross-cultural research. We developed (Study 1: N = 2924 students in 16 nations) and validated across cultures (Study 2: N = 7279 adults from 55 cultural groups in 33 nations) a new 7-dimensional model of self-reported ways of being independent or interdependent. Patterns of global variation support some of Markus and Kitayama's predictions, but a simple contrast between independence and interdependence does not adequately capture the diverse models of selfhood that prevail in different world regions. Cultural groups emphasize different ways of being both independent and interdependent, depending on individualism-collectivism, national socioeconomic development, and religious heritage. Our 7-dimensional model will allow future researchers to test more accurately the implications of cultural models of selfhood for psychological processes in diverse ecocultural contexts. (PsycINFO Database Record

We enter the 21st century contending with the end of the Cold War's legacy of political uncertainty, expecting youth to play a significant part in the search for new principles that will bring about stability in the world political order. In forging the future, youth will have to collaborate with adults, but on terms more fitting of the historical circumstances that lie ahead than those of the past. This was the framework adopted by a group of social scientists who held several discussions to reflect on the issues and opportunities that bear on youth's civic engagement and development in the century that has just opened. The present article describes the results of those conversations, starting with the issue of defining civic competence, and the finding that an expansive definition is needed to match the real‐world circumstances that affect its development for youth internationally. Specific conditions, such as globalization, information – communication technology, and immigration, are emphasized as forces that affect youth and need to be taken into account by educators and policy makers. In this regard, responsibilities of schools, government, the commercial sector, and community organizations are outlined. Each is viewed as a potential constructive force for promoting engagement insofar as youth's strengths are recognized and focus is placed on building on youth's proven capacities. As always, it is youth’s task to make history in the future and society's obligation to provide youth with sufficient resources and an honest basis for hope in carrying out this task. The authors' policy recommendations are founded on this reciprocal relation that binds the youth generation with its elders in the common task of preserving, while transforming, society for the good of humanity.

Brain-derived neurotrophic factor (BDNF) is a small, basic protein purified from the mammalian brain that has been shown previously to support the survival of cultured spinal sensory neurons (Barde et al., 1982). In current studies, BDNF was tested for its ability to support the survival of cultured CNS cells isolated from the perinatal rat retina. Both immunofluorescent labeling of Thy-1 and prior retrograde labeling with HRP were used as retinal ganglion cell markers in vitro. With embryonic day (E) 17 retinas, it was found that BDNF allowed the survival of a small subpopulation of neurons (about 7% of the cells plated at this age) identified by the immunofluorescent labeling of Thy-1. No detectable effects were seen when either the total number of cells or the number of tetanus toxin-positive neurons was measured. BDNF also had an effect on cultured neurons retrogradely labeled after HRP injections in the superior colliculi of neonatal rats. The BDNF-responsive population was therefore detected only in retinal cultures with specific markers and identified as consisting of retinal ganglion cells. These cells could be enriched about 80-fold by density gradient centrifugation, and purified ganglion cell cultures were shown to be responsive to BDNF. Whereas with E17 retinas, the number of surviving Thy-1 positive neurons could be kept constant for at least 4 d, the survival of postnatal neurons was only transiently increased by BDNF. We conclude that in the retina, BDNF affects only the survival of ganglion cells in vitro by a direct action on these cells. The results are discussed in terms of target-derived neurotrophic support during development.

We present a time-correlated single photon counting (TCPSC) technique that allows time-resolved multi-wavelength imaging in conjunction with a laser scanning microscope and a pulsed excitation source. The technique is based on a four-dimensional histogramming process that records the photon density over the time of the fluorescence decay, the x-y coordinates of the scanning area, and the wavelength. The histogramming process avoids any time gating or wavelength scanning and, therefore, yields a near-perfect counting efficiency. The time resolution is limited only by the transit time spread of the detector. The technique can be used with almost any confocal or two-photon laser scanning microscope and works at any scanning rate. We demonstrate the application to samples stained with several dyes and to CFP-YFP FRET.

[1] A strong 50–35 Ma decrease in India-Asia convergence is generally ascribed to continent-continent collision. However, a convergence rate increase of similar magnitude occurred between ∼65–50 Ma. An earlier increase occurred at ∼90 Ma. Both episodes of accelerated convergence followed upon arrival of a mantle plume below and emplacement of a large igneous province (LIP) on the Indian plate. We here first confirm these convergence rate trends, reassessing the Indo-Atlantic plate circuits. Then, using two different numerical models, we assess whether plume head arrival and its lateral asthenospheric flow may explain the plate velocity increases and whether decreased plume flux and increasing continent-plume distance may explain deceleration, even without continental collision. The results show that plume head arrival can indeed lead to absolute Indian plate motion accelerations on the order of several cm/yr, followed by decelerations on timescales similar to the reconstructed fluctuations. The 90 Ma increase could potentially be explained as response to the Morondova mantle plume alone. The 65–50 Ma convergence rate increase, however, is larger than can be explained by plume head spreading alone. We concur with previous hypotheses that plume-induced weakening of the Indian continental lithosphere-asthenosphere coupling and an increased slab pull and ridge push efficiency are the most likely explanations for the large convergence rate increase. The post-50 Ma decrease is best explained by orogeny-related increased trench resistivity, decreased slab pull due to continental subduction, and possibly restrengthening of lithosphere-asthenosphere coupling upon plume demise.

Plastic debris in the environment contains plasticizers, such as phthalates (PAEs), that can be released during plastic aging. Here, two common plastic materials, an insulation layer of electric cables (polyvinyl chloride, PVC-cables) and plastic garbage bag (polyethylene, PE-bags), were incubated in natural seawater under laboratory conditions, and the PAE migration to the seawater phase was studied with varying light and bacterial conditions over a 90-day time course. Free PAEs diluted in seawater were also studied for bacterial degradation. Our results showed that, within the first month of incubation, both plastic materials significantly leached out PAEs into the surrounding water. We found that di-isobutyl phthalate (DiBP) and di-n-butyl phthalate (DnBP) were the main PAEs released from the PE-bags, with the highest values of 83.4 ± 12.5 and 120.1 ± 18.0 ng g–1 of plastic, respectively. Furthermore, dimethyl phthalate (DMP) and diethyl phthalate (DEP) were the main PAEs released from PVC-cables, with mass fractions as high as 9.5 ± 1.4 and 68.9 ± 10.3 ng g–1, respectively. Additionally, we found that light and bacterial exposure increased the total amount of PAEs released from PVC-cables by a factor of up to 5, whereas they had no influence in the case of PE-bags.

Transcription in plastids is mediated by a plastid-encoded multimeric (PEP) and a nuclear-encoded single-subunit RNA polymerase (NEP) and a still unknown number of nuclear-encoded factors. By combining gel filtration and affinity chromatography purification steps, we isolated transcriptionally active chromosomes from Arabidopsis thaliana and mustard (Sinapis alba) chloroplasts and identified 35 components by electrospray ionization ion trap tandem mass spectrometry. Eighteen components, called plastid transcriptionally active chromosome proteins (pTACs), have not yet been described. T-DNA insertions in three corresponding genes, ptac2, -6, and -12, are lethal without exogenous carbon sources. Expression patterns of the plastid-encoded genes in the corresponding knockout lines resemble those of Deltarpo mutants. For instance, expression of plastid genes with PEP promoters is downregulated, while expression of genes with NEP promoters is either not affected or upregulated in the mutants. All three components might also be involved in posttranscriptional processes, such as RNA processing and/or mRNA stability. Thus, pTAC2, -6, and -12 are clearly involved in plastid gene expression.

A covalently-bonded atom typically has a region of lower electronic density, a "σ-hole," on the side of the atom opposite to the bond, along its extension. There is frequently a positive electrostatic potential associated with this region, through which the atom can interact attractively but noncovalently with negative sites. This positive potential reflects not only the lower electronic density of the σ-hole but also contributions from other portions of the molecule. These can significantly influence both the value and also the angular position of the positive potential, causing it to deviate from the extension of the covalent bond. We have surveyed these effects, and their consequences for the directionalities of subsequent noncovalent intermolecular interactions, for atoms of Groups IV-VII. The overall trends are that larger deviations of the positive potential result in less linear intermolecular interactions, while smaller deviations lead to more linear interactions. We find that the deviations of the positive potentials and the nonlinearities of the noncovalent interactions tend to be greatest for atoms of Groups V and VI. We also present arguments supporting the use of the 0.001 a.u. contour of the electronic density as the molecular surface on which to compute the electrostatic potential.

It has long been a matter of debate whether recovery from aphasia after left perisylvian lesions is mediated by the preserved left hemispheric language zones or by the homologous right hemisphere regions. Using PET, we investigated the short-term changes in the cortical network involved in language comprehension during recovery from aphasia. In 12 consecutive measurements of regional cerebral blood flow (rCBF), four patients with Wernicke's aphasia, caused by a posterior left middle cerebral artery infarction, were tested with a language comprehension task. Comprehension was estimated directly after each scan with a modified version of the Token Test. In the interval between the scans, the patients participated in brief, intense language comprehension training. A significant improvement in performance was observed in all patients. We correlated changes in blood flow measured during the language comprehension task with the scores achieved in the Token Test. The regions which best correlated with the training-induced improvement in verbal comprehension were the posterior part of the right superior temporal gyrus and the left precuneus. This study supports the role of the right hemisphere in recovery from aphasia and demonstrates that the improvement in auditory comprehension induced by specific training is associated with functional brain reorganization.

Structures formed during interaction of cationic liposomes and plasmid DNA were studied by freeze-fracture electron microscopy and their morphology was found to be dependent on incubation time and DNA concentration. These structures were formed with liposomes composed of DC-Chol and DOPE after 30 min incubation at DNA:lipid concentrations encompassing maximal transfection activity. They resembled liposome complexes (meatballs) and additionally bilayer-covered DNA tubules (spaghetti), whereby the DNA-tubules were found to be connected to the liposome complexes as well as occurring free in the suspension. At later times and higher DNA-to-liposome ratios the complexes grow larger while their membranes become discontinuous, allowing the self-encapsulation of the DNA. The relative transfection potency of the various morphologically distinct structures is discussed.

The structural, dielectric, lattice-dynamical, and electronic properties of biaxially and uniaxially strained group-III nitrides are studied ab initio using a pseudopotential-plane-wave method. A linear-response approach to the density-functional theory is used to calculate the dielectric constants, the dynamical effective charges, and the phonon frequencies. For a given strain the atomic coordinates are determined from the equilibrium condition. The elastic properties of GaN and AlN are characterized in terms of ratios of the elastic stiffness constants, which allow for a critical comparison with literature data; unreliable ones are pointed out. Electronic as well as phonon deformation potentials and the respective strain and stress coefficients are determined. We show that the quasicubic approximation does not hold for the electronic interband deformation potentials of GaN but for those of AlN. Seeming discrepancies between experimental and theoretical results can be widely resolved using suitable parameters and correct stress-strain relations. We find that the stress obtained from biaxial-strain-induced shifts of the high-frequency ${E}_{2}$ phonon or excitonic transitions should be higher than determined by other authors.

An ab initio pseudopotential method based on density functional theory, generalized gradient corrections to exchange and correlation, and projector-augmented waves is used to investigate structural, energetical, electronic, and optical properties of $\mathrm{MgO}$, $\mathrm{ZnO}$, and $\mathrm{CdO}$ in rocksalt, cesium chloride, zinc blende, and wurtzite structure. In the case of $\mathrm{MgO}$ we also examine the nickel arsenide structure and a graphitic phase. The stability of the ground-state phases rocksalt $(\mathrm{MgO},\mathrm{CdO})$ and wurtzite $(\mathrm{ZnO})$ against hydrostatic pressure and biaxial strain is studied. We also present the band structures of all polymorphs as well as the accompanying dielectric functions. We discuss the physical reasons for the anomalous chemical trend of the ground-state geometry and the fundamental gap with the size of the group-II cation in the oxide. The role of the shallow $\mathrm{Zn}3d$ and $\mathrm{Cd}4d$ electrons is critically examined.

We use a plane-wave-pseudopotential code to study the surface energetics for the elemental semiconductors Ge, Si, and diamond from first principles. Various reconstruction geometries including 1\ifmmode\times\else\texttimes\fi{}1, 2\ifmmode\times\else\texttimes\fi{}1, $c(4\ifmmode\times\else\texttimes\fi{}2),$ $c(2\ifmmode\times\else\texttimes\fi{}8),$ and 7\ifmmode\times\else\texttimes\fi{}7 of the low-index surfaces (100), (110), and (111) are optimized with respect to the atomic coordinates. The resulting total energies are related to the accompanying band structures. Chemical trends are derived. The different reconstruction behavior is discussed in terms of atomic sizes and orbital energies.

Ectomycorrhizal fungi are thought to have a key role in mobilizing organic nitrogen that is trapped in soil organic matter (SOM). However, the extent to which ectomycorrhizal fungi decompose SOM and the mechanism by which they do so remain unclear, considering that they have lost many genes encoding lignocellulose-degrading enzymes that are present in their saprotrophic ancestors. Spectroscopic analyses and transcriptome profiling were used to examine the mechanisms by which five species of ectomycorrhizal fungi, representing at least four origins of symbiosis, decompose SOM extracted from forest soils. In the presence of glucose and when acquiring nitrogen, all species converted the organic matter in the SOM extract using oxidative mechanisms. The transcriptome expressed during oxidative decomposition has diverged over evolutionary time. Each species expressed a different set of transcripts encoding proteins associated with oxidation of lignocellulose by saprotrophic fungi. The decomposition 'toolbox' has diverged through differences in the regulation of orthologous genes, the formation of new genes by gene duplications, and the recruitment of genes from diverse but functionally similar enzyme families. The capacity to oxidize SOM appears to be common among ectomycorrhizal fungi. We propose that the ancestral decay mechanisms used primarily to obtain carbon have been adapted in symbiosis to scavenge nutrients instead.

Social evaluation occurs at personal, interpersonal, group, and intergroup levels, with competing theories and evidence. Five models engage in adversarial collaboration, to identify common conceptual ground, ongoing controversies, and continuing agendas: Dual Perspective Model (Abele & Wojciszke, 2007); Behavioral Regulation Model (Leach, Ellemers, & Barreto, 2007); Dimensional Compensation Model (Yzerbyt et al., 2005); Stereotype Content Model (Fiske, Cuddy, Glick, & Xu, 2002); and Agency-Beliefs-Communion Model (Koch, Imhoff, Dotsch, Unkelbach, & Alves, 2016). Each has distinctive focus, theoretical roots, premises, and evidence. Controversies dispute dimensions: number, organization, definition, and labeling; their relative priority; and their relationship. Our first integration suggests 2 fundamental dimensions: Vertical (agency, competence, "getting ahead") and Horizontal (communion, warmth, "getting along"), with respective facets of ability and assertiveness (Vertical) and friendliness and morality (Horizontal). Depending on context, a third dimension is conservative versus progressive Beliefs. Second, different criteria for priority favor different dimensions: processing speed and subjective weight (Horizontal); pragmatic diagnosticity (Vertical); moderators include number and type of target, target-perceiver relationship, context. Finally, the relation between dimensions has similar operational moderators. As an integrative framework, the dimensions' dynamics also depend on perceiver goals (comprehension, efficiency, harmony, compatibility), each balancing top-down and bottom-up processes, for epistemic or hedonic functions. One emerging insight is that the nature and number of targets each of these models typically examines alters perceivers' evaluative goal and how bottom-up information or top-down inferences interact. This framework benefits theoretical parsimony and new research. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

AIMS: As a toxic metal, cadmium (Cd) affects microbial and plant metabolic processes, thereby potentially reducing the efficiency of microbe or plant-mediated remediation of Cd-polluted soil. The role of siderophores produced by Streptomyces tendae F4 in the uptake of Cd by bacteria and plant was investigated to gain insight into the influence of siderophores on Cd availability to micro-organisms and plants. METHODS AND RESULTS: The bacterium was cultured under siderophore-inducing conditions in the presence of Cd. The kinetics of siderophore production and identification of the siderophores and their metal-bound forms were performed using electrospray ionization mass spectrometry. Inductively coupled plasma spectroscopy was used to measure iron (Fe) and Cd contents in the bacterium and in sunflower plant grown in Cd-amended soil. Siderophores significantly reduced the Cd uptake by the bacterium, while supplying it with iron. Bacterial culture filtrates containing three hydroxamate siderophores secreted by S. tendae F4 significantly promoted plant growth and enhanced uptake of Cd and Fe by the plant, relative to the control. Furthermore, application of siderophores caused slightly more Cd, but similar Fe uptake, compared with EDTA. Bioinoculation with Streptomyces caused a dramatic increase in plant Fe content, but resulted only in slight increase in plant Cd content. CONCLUSION: It is concluded that siderophores can help reduce toxic metal uptake in bacteria, while simultaneously facilitating the uptake of such metals by plants. Also, EDTA is not superior to hydroxamate siderophores in terms of metal solubilization for plant uptake. SIGNIFICANCE AND IMPACT OF THE STUDY: The study showed that microbial processes could indirectly influence the availability and amount of toxic metals taken up from the rhizosphere of plants. Furthermore, although EDTA is used for chelator-enhanced phytoremediation, microbial siderophores would be ideal for this purpose.