Case Study in The Northern Cape (Loopeng Area), South Africa, Confirming Occurrence of a Collapsible Soil Structure in Transported Soils

Testing was performed on transported soils belonging to recently deposited sandy-silty soil deposits occurring in the Northern Cape Province, South Africa in order to determine the occurrence and order of magnitude of a collapsing sand soil structure. Various empirical geotechnical characteristics including: in situ soil profile structure description, particle grading curve and clay content, soil classification, soil density and void ratio were compared to collapse potential values determined with oedometer testing in order to judge the success with which the empirical characteristics can be utilized to predict the occurrence of a collapsible soil structure.From the results it is clear that a collapsing sand structure exists in the transported soils and the empirical descriptors mostly correctly indicate the occurrence or the particular soil structure when compared to previous studies on collapsing sands. The one descriptor which reflects a relatively poor correction between the descriptor and the soil structure (in situ soil profile structure description) is considered to be a poor indicator of the collapsible soil structure due to erroneous or poor in situ soil structure observations resulting from unfavourable local conditions namely dry, dusty soil conditions and very brief intact standup time of test pit side walls.

The Principle of Maximal Simplicity for Modular Inorganic Crystal Structures

Modularity is an important construction principle of many inorganic crystal structures that has been used for the analysis of structural relations, classification, structure description and structure prediction. The principle of maximal simplicity for modular inorganic crystal structures can be formulated as follows: in a modular series of inorganic crystal structures, the most common and abundant in nature and experiments are those arrangements that possess maximal simplicity and minimal structural information. The latter can be quantitatively estimated using information-based structural complexity parameters. The principle is applied for the modular series based upon 0D (lovozerite family), 1D (biopyriboles) and 2D (spinelloids and kurchatovite family) modules. This principle is empirical and is valid for those cases only, where there are no factors that may lead to the destabilization of simplest structural arrangements. The physical basis of the principle is in the relations between structural complexity and configurational entropy sensu stricto (which should be distinguished from the entropy of mixing). It can also be seen as an analogy of the principle of least action in physics.

Spin states, bonding and magnetism in mixed valence iron(0)–iron(II) complexes

We report the synthesis of two complexes featuring unsupported Fe–Fe bonds between a diketiminate/dialdiminate-coordinated iron site and a cyclopentadienyl dicarbonyl iron site. Mössbauer spectroscopy, SQUID magnetometry and computational analysis indicate that the most accurate electronic structure description is with the Fe(CO)2Cp site as low spin iron(0), and it acts as a Lewis base toward the high spin iron(II) of the LFe fragment which is a Lewis acid. In both compounds, the three-coordinate high-spin iron(II) site has large zero-field splitting (zfs), up to D = –50 cm–1.

Reversible Topochemical Polymerization and Depolymerization of a Crystalline Three-Dimensional Porous Organic Polymer with C–C Bond Linkages

Three-dimensionally connected porous organic polymers are of interest because of their potential in adsorption, separation, and sensing, among others. When crystalline, they also afford accurate structure description, which in turn can enable particular functions. However, crystallization of three-dimensional (3D) polymers is challenging. This is especially true when targeting polymerization via stable C–C bonds, whose formation is usually irreversible and does not allow for error correction typically required for crystallization. Here, we report polyMTBA, the first 3D-connected crystalline organic polymer with permanent porosity, here formed via C–C linkages. High crystallinity is achieved by solid-state topochemical reaction within monomer MTBA crystals. polyMTBA is recyclable via thermal depolymerization and is solution-processable via its soluble monomers. These results reveal topochemical polymerization as a compelling methodology for generating stable, crystalline, and porous 3D organic frameworks.

Reversible Topochemical Polymerization and Depolymerization of a Crystalline Three-Dimensional Porous Organic Polymer with C–C Bond Linkages

Three-dimensionally connected porous organic polymers are of interest because of their potential in adsorption, separation, and sensing, among others. When crystalline, they also afford accurate structure description, which in turn can enable particular functions. However, crystallization of three-dimensional (3D) polymers is challenging. This is especially true when targeting polymerization via stable C–C bonds, whose formation is usually irreversible and does not allow for error correction typically required for crystallization. Here, we report polyMTBA, the first 3D-connected crystalline organic polymer with permanent porosity, here formed via C–C linkages. High crystallinity is achieved by solid-state topochemical reaction within monomer MTBA crystals. polyMTBA is recyclable via thermal depolymerization and is solution-processable via its soluble monomers. These results reveal topochemical polymerization as a compelling methodology for generating stable, crystalline, and porous 3D organic frameworks.

Approaching probabilistic laws

In the general problem of verisimilitude, we try to define the distance of a statement from a target, which is an informative truth about some domain of investigation. For example, the target can be a state description, a structure description, or a constituent of a first-order language (Sect. 1). In the problem of legisimilitude, the target is a deterministic or universal law, which can be expressed by a nomic constituent or a quantitative function involving the operators of physical necessity and possibility (Sect. 2). The special case of legisimilitude, where the target is a probabilistic law (Sect. 3), has been discussed by Roger Rosenkrantz (Synthese, 1980) and Ilkka Niiniluoto (Truthlikeness, 1987, Ch. 11.5). Their basic proposal is to measure the distance between two probabilistic laws by the Kullback–Leibler notion of divergence, which is a semimetric on the space of probability measures. This idea can be applied to probabilistic laws of coexistence and laws of succession, and the examples may involve discrete or continuous state spaces (Sect. 3). In this paper, these earlier studies are elaborated in four directions (Sect. 4). First, even though deterministic laws are limiting cases of probabilistic laws, the target-sensitivity of truthlikeness measures implies that the legisimilitude of probabilistic laws is not easily reducible to the deterministic case. Secondly, the Jensen-Shannon divergence is applied to mixed probabilistic laws which entail some universal laws. Thirdly, a new class of distance measures between probability distributions is proposed, so that their horizontal differences are taken into account in addition to vertical ones (Sect. 5). Fourthly, a solution is given for the epistemic problem of estimating degrees of probabilistic legisimilitude on the basis of empirical evidence (Sect. 6).

Crystal structure of the uranyl arsenate mineral hügelite, Pb2(UO2)3O2(AsO4)2(H2O)5, revisited: a correct unit cell, twinning and hydrogen bonding

Revisiting the structure of uranyl arsenate mineral hügelite provided some corrections to the available structural data. The previous twinning model (by reticular merohedry) in hügelite has been corrected. Twinning of the monoclinic unit cell [a = 7.0189 (7) Å, b = 17.1374 (10) Å, c = 8.1310 (10) Å and β = 108.904 (10)°], which can be expressed as a mirror in [100], leads to a pseudo-orthorhombic unit cell (a = 7.019 Å, b = 17.137 Å, c = 61.539 Å and β = 90.02°), which is eight times larger, with respect to the unit-cell volume, than a real cell. Moreover, the unit cell of chosen here and the unit cell given by the previous structure description both lead to the same supercell. A new structure refinement undertaken on an untwinned crystal of hügelite resulted in R = 4.82% for 12 864 reflections with I obs > 3σ(I) and GOF = 1.12. The hydrogen-bonding scheme has been proposed for hügelite for the first time.

Histologis Perkembangan Embrio Ayam pada Masa Inkubasi Satu sampai Tujuh Hari

ABSTRAK. Penelitian ini bertujuan melihat perkembangan embrio ayam secara histologi pada waktu 1, 2, 3, 4, 5, dan 7 hari inkubasi. Sampel yang digunakan adalah telur fertil yang didapat dari teaching farm Fakultas Pertanian Jurusan Peternakan Universitas Syiah Kuala. Pengamatan secara makroskopis dilakukan pada setiap sampel embrio ayam, sementara pengamatan mikroskopis struktur embrio ayam dilakukan dengan pembuatan preparat histologi. Hasil penelitian ini menampilkan data perkembangan embrio ayam secara spesifik dari umur inkubasi hari ke-1 sampai hari ke-7. Secara makroskopik dan mikroskopis, gambaran umum perkembangan embrio ayam selaras dengan informasi tabel pertumbuhan embrio ayam. Secara histologis, gambaran perkembangan struktur embrio ayam baru dapat diamati dengan baik yaitu pada umur inkubasi hari ke-3 sampai hari ke-7. Dapat disimpulkan bahwa secara histologi perkembangan embrio ayam baru dapat diamati pada masa inkubasi hari ke-3. Penelitian ini juga dapat dijadikan sebagai bahan acuan dasar untuk penelitian lanjutan terutama terhadap organogenesis pada embrio ayam. (Histological evaluation on the development of chicken embryo during the incubation periodfrom 1st to 7th days) ABSTRACT. The aim of this study was to find out the development of chicken embryos at day 1st, 2nd, 3rd, 4th, 5th, and 7th of incubation by histological method. The samples used were the fertile eggs obtained from the teaching farm of the Faculty of Agriculture, Department of Animal Husbandry, Syiah Kuala University. Macroscopic observations were made on each embryos sample, while microscopic observations of the embryos structure were carried out by histological preparations procedure. The results of this study presented the specific data of chicken embryos development from day 1st to day 7th of incubation. The macroscopic and microscopic data showed the general description of chicken embryos development similar to the information on the chicken embryo growth table. The microscopic results showed the structure description of the chicken embryos can be well observed at day 3rd to the day 7th of incubation. It can be seen the development of chicken embryos can be observed by histology method on day 3rd of incubation. This research can also be used as a basic reference for further research, especially on organogenesis of chicken embryos.

The Self-concept model as experience evaluation process

This article substantiates the relevance of studying the Self-concept as a phenomenon aimed at achieving Self-actualization and structurization of behavior. The question is raised about the prerequisites that allow a person to differentiate experience, thereby underlining the need to study the ontogenesis of the Self-concept as the foundation for the evaluative process that integrates the three gradually forming layers. This serves as the basis for formulating the definition of the Self-concept, and describing each of its layers (organismic, social, and conceptual). Their role in the experience evaluation process, as well as applicable to behavior, is explored. The boundaries are established between the layers and the phenomena introduced by K. Rogers; thus, the social layer is naturally introjective and essential. The subject of this research is the determination of each layer of possible disorders within ontogenesis, and relative to this, the risk of transition of the Self-concept from the process to the newly formed structure. Description is given to possibilities of application of this model in psychological practice. Firstly, it allows understanding the incongruity of the customer, as well as self-image of the psychologist in their non-empathic, but congruent responses. Secondly, this model structures the interaction in psychotherapy, helping to establish the typology of psychological disorder, as well as choose appropriate interventions remaining within the framework of humanistic methodology, without eclectic selection of the techniques. In conclusion, the authors reveal the potential of scientific study of the Self-concept model, which consists in understanding the customer and their incongruity. This model contributes to most accurate choice of techniques and methods, as well as means of interaction with the customer, depending on the dysfunction of the layer.

Bismuth Polycations Revisited: Alternative Synthesis and Electronic Structure of Bi6Br7, and Bonding in Main-Group Polyatomic Ions from a Direct Space Perspective

A bismuth subbromide, Bi6Br7, was synthesized in the form of single crystals using the reaction between Bi and Hg2Br2 in a gradient furnace. Its crystal structure was reinvestigated by low-temperature single-crystal X-ray diffraction (Pnnm, a = 15.4996(6) Å, b = 23.6435(7) Å, c = 9.0231(2) Å, Z = 8, R1 = 0.041, wRall = 0.087). Based on the diffraction data, the structure description was revised as containing Bi95+ cluster polycations and 1∞[Bi3Br145−] ladder-like anions. DFT calculations of band structure showed the compound to be a narrow-gap semiconductor with a band gap of ca. 1.3 eV, with the nature of the compound as ionic salt confirmed by charge density analysis. Direct-space bonding analysis based on the ELF topology and QTAIM partitioning, performed for all known homoatomic bismuth polycations, as well as isoelectronic main-group metal ions, shows patterns of localized pairwise and three-center bonding forming the frameworks of the clusters. In addition to obtaining new data, the use of highly augmented basis sets allowed us to revise and amend several previously made conclusions regarding bonding in such species.