Cornetite: Modulated densely-packed Cu2+ oxysalt

Summary The crystal structure of cornetite, Cu₃(PO₄)(OH)₃, orthorhombic, a = 10.854(1), b = 14.053(3), c = 7.086(2), Å, V = 1080.8(3) ų, Z = 8, space group Pbca, has been refined to an R-index of 3.9% for 1231 observed reflections (I > 3I), measured with MoK X-radiation on an automated four-circle diffractometer. The structure consists of edge sharing zig-zag chains of distorted octahedra, cross-linked by edge-sharing octahedral dimers into complex octahedral layers. Adjacent layers are corner-linked together by neighbouring octahedra and PO₄ tetrahedra into a densely-packed heteropolyhedral framework, in which the phosphate tetrahedra share edges with the octahedral dimers. The polyhedral layers exhibit a commensurate modulation that results from the interaction between local relaxation of Jahn-Teller distorted octahedra and the long-range requirements of translational periodicity.

---

Cornetit: Ein moduliertes, dicht gepacktes Oxosalz des zweiwertigen Kupfers

Zusammenfassung Die Kristallstruktur des Cornetits, Cu₃(PO4)(OH)3, orthorhombisch, a = 10,854(1), b = 14,053(3), c = 7,086(2,) Å, V = 1080,8(3) ų, Z = 8, Raumgruppe Pbca, wurde mit 1231 beobachteten Röntgenreflexen (I > 3I), die mit MoK-Strahlung auf einem automatischen Vierkreis-Diffraktometer gesammelt worden waren, auf einen R-Wert von 3,9% verfeinert. Die Struktur besteht aus kantenverknüpften Zickzack-Ketten verzerrter Oktaeder, die über kantenverknüfte Oktaeder-Dimere zu komplizierten Oktaederschichten verbunden sind. Benachbarte Schichten sind über Ecken durch benachbarte Oktaeder und PO₄-Tetraeder zu einem dichtgepackten, heteropolyedrischen Gerüst verknüpft, in welchem die Phosphattetraeder mit den Oktaeder-Dimeren Kanten gemeinsam haben. Die Polyederschichten zeigen eine kommensurable Modulierung, die aus der Wechselwirkung zwischen der lokalen Relaxation von Jahn-Teller-verzerrten Oktaedern und den Forderungen der translatorischen Periodizität über größere Entfernungen resultiert.

---

---

With 5 Figures     

Planning for coastal zone management programme in Nigeria

Conclusions The coastal zone in Nigeria has some problems and if both the Federal and the State Governments continue their movements away from viewing the coastal zone as an important and ecologically unique and fragile environment, the problem will retard the resources of the area. Developing countries like Nigeria lag behind the developed world in the provision of legislations to protect their citizens, coastal environment, and companies and firms. Presently, the development of Nigeria strictly comes from the coastal zone, therefore Government at all levels must be brought to see the coastal zones as a district and important region, and to provide a CZMP network capable of successfully resolving the issues particular to it.     

Developing perspectives upon the areal extent of Israel: An outline evaluation

This paper considers certain proposals for the future of the present Israeli-Occupied Territories. An essential yet brief review of various backgrounds, including the notion of Eretz Yisrael, is presented. The two principal Israeli viewpoints on the future of the territories, the Eretz Yisrael and the Regional Compromise positions are considered in some detail. While the so-termed Jordanian Option is outlined the Joshua Option is introduced as it may possibly indicate an even broader dimension for future deliberations and actions. A brief introduction to the proceeding study of Jewish settlement-development in the Samarian core is presented. The importance of such fieldwork is stressed. The overall contentious nature of the subject is emphasized yet academic consideration must proceed.     

Resource partitioning and regional development strategies in the Ecuadorian Amazon

This paper argues that the process of establishing claims and control over resources, referred to as resource partitioning, structures frontier societies in ways which impede subsequent efforts at rural development. Conflicts over claims to resources create divisions among local elites which prevent the formation of coalitions to promote development. Struggles for control over the flow of resources out of a region cause regional development agencies to pursue transportation policies which retard development by isolating the region from all but one commercial center. A case study of resource partitioning and rural development efforts in the Ecuadorian Amazon illustrates the argument.     

Forty years of rain forest ecology 1948–1988 in perspective

The main fields of research in tropical rain forest ecology today are briefly described and the development of the subject over the past forty years is outlined.     

Thrust tectonics along the north-western continental margin of Sabah/Borneo

Widely accepted plate tectonic models suggest that an inactive subduction zone lies along the north-west continental margin of Sabah. In contrast, interpretation of reflection seismic data acquired by BGR shows an autochthonous continental terrane comprising an Oligocene to Early Miocene carbonate platform being progressively overthrust by an allochthonous rock complex. Progressive compression resulted in the development of four structural zones: Imbricated thrust sheets (Zone III); two thrust sheet systems one on top of the other (Zone IV); a complex zone with multiphase deformation (Zone V); and piercement ridges (Zone VI).

---

Zusammenfassung Nach herkömmlichen plattentektonischen Vorstellungen soll eine inaktive Subduktionszone am nordwestlichen Kontinentalrand von Sabah liegen. Reflexionsseismische Meßdaten der BGR zeigen jedoch, daß hier autochthone kontinentale Kruste mit einer oligozänen-frühmiozänen Karbonatplattform progressiv von einem allochthonen Gesteinsverband überschoben wird. Fortschreitender Zusammenschub seit dem frühen Miozän führte zur Anlage von vier Deformationszonen: Tekonische Schuppen (Zone III); zwei übereinander geschobene Verschuppungssysteme (Zone IV); Gürtel mit mehrphasiger Deformation (Zone V) und Durchspießungsstrukturen (Zone VI).

---

Résumé Les modèles géodynamiques que l'on admet habituellement comportent une zone de subduction inactive le long de la marge continentale nord-occidentale de Sabah. Toutefois, des mesures de sismique-réflexion exécutées par le BGR font apparaître qu'à cet endroit, une croûte continentale autochtone, comportant une plateforme carbonatée oligocène à éomiocène, est chevauchée progressivement par un complexe allochtone. La compression, qui s'est manifestée progressivement depuis le Miocène inférieur, a engendré quatre zones structurales: un ensemble d'écailles tectoniques (zone III); deux systèmes de lames tectoniques charriés l'un sur l'autre (zone IV); une zone complexe à déformation multiphasée (zone V); des structures d'extrusion tectonique (zone VI).

---

, - Sabah'a. , - . 4-? : ( 3), ( 4) ( 5) ( 6).

     

The performance of Nigeria's fishery sector: an empirical analysis, 1976–85

London is an international tourist destination and one of the world's most well known tourist capitals. Over 23 million overseas and domestic visitors contributed £ 4700 million to the city's economy in 1987. In this paper, the implications of a continued growth in international and domestic tourism are considered in the light of recent predictions which envisage that London's overseas and domestic visitors will rise from 23 million in 1987 to 27 million in 1990. One of the most pressing issues which tourist agencies such as the London Tourist Board face, is directing some tourists to new areas and attractions away from the existing concentration in the West End of London. In this paper, the existing and proposed development of tourism in the East End of London (London Docklands) will beexamined as a new area with the potential to attract visitors from the West End. London Docklands has attracted international attention due to the prestigious and controversial regeneration of the area where commercial and residential development has been stimulated by a government funded Urban Development Corporation. Tourist and leisure developments seem set to bring a lasting economic benefit to the area though they have attracted very little attention to date.     

Jari: A pulp plantation in the Brazilian Amazon

Jari plantation is the largest pulp growing operation in the humid tropics, and occupies about 1000 sqkm previously covered by tropical forest. A study of five sites at Jari in 1980 indicated declining soil fertility, and low productivity of pulpwood. Low pulp production at Jari was caused by several factors, one of which appeared to be low soil fertility. The sams sites were re-evaluated in 1987. There was no discernable trend in either nutrients or productivity since 1980.Although productivity and nutrient stocks may have stabilized, low profitability caused by low pulp production resulted in the sale of Jari in 1982, for a $ 720 million loss. Despite growth rates at Jari which were too low to produce a profit on original investment, another plantation is planned for the eastern Amazon which is 10 times the size of Jari.     

Biogeochemistry of the Madeira river basin

A biogeochemical characterization of the Madeira river basin has been made to evaluate the local and global effects of possible alterations in the ecosystem caused by recent intensive occupation in Rondonia state. During the period April 1983—January 1986, sampling was made both by land and river along the tributaries and main channel of the Madeira river. The parameters analysed lead to a detailed study of the physicochemical quality of the waters of the basin and their relationship with the local geology, associated with the transport of solid material and the hydrological behavior of the ecosystem.Penman's method adapted to tropical rainforest conditions was used to evaluate the potential evapotranspiration for the basin. Estimated potential evapotranspiration was 1420 mm/y, 77% due to the energy balance. Real evapotranspiration was 94% of the estimated potential and the main residence time of the rain water in the basin was 2 months. The isotopic behavior of Hydrogen and Oxygen in the river waters of the region was typical of great rivers, the values being more positive during the dry season and more negative during the rainy season. An isotopic gradient of ¹⁸O 0.038 ()/100 km, was established from Porto Velho station to the estuary, which was considered low when compared with the value of 0.063 ()/100 km, obtained for the Amazon river.In general, the waters of the tributaries were poor in dissolved ion species when compared with the main channel of the Madeira river. Seasonal variation in the transport of suspended sediment kept the same pattern, greater transport being observed on rising water than during high water. A transport of 2.85 million tons per day was observed in the Madeira river near the mouth.     

Dispersion of surface plumes in the Southern North Sea

Summary Continuous releases of fluorescent dye were made in the southern North Sea and the power law dependence of the plume width, represented by _y , against the diffusion time determined. The spreading was non-Fickian and could be represented in the form _y ² =B ² t whereB was a diffusion velocity of magnitude 1.4×10^–2 m/s. Such spreading was reproduced in both particle tracking and finite difference plume models by allowing the horizontal diffusivity,K _H, to depend linearly on diffusion time. The weakness of this method is that it is not clear how the diffusion parameters can be extrapolated to weather conditions that are different to those prevailing at the time of the experiments. However, comparable spreading rates were obtained by combining a Fickian diffusion model with an advective field that represented the near-surface current shears due to wind and waves. The resulting shear diffusion effect produced realistic simulation of the observed dispersion rates. An advantage of this approach is that it enables predictions to be made over a range of weather conditions provided that the wind and wave shears can be accurately parameterized.

---

Ausbreitung von Tracerwolken an der Oberfläche in der südlichen Nordsee

Zusammenfassung Fluoreszierender Farbstoff wurde in der südlichen Nordsee kontinuierlich freigesetzt und die Breite der Wolke, repräsentiert durch _y , in Abhägigkeit von der Ausbreitungszeit bestimmt. Die Ausbreitung folgte nicht dem Fickschen Ansatz und konnte in der Form _y ² =B ² t dargestellt werden, wobeiB eine Ausbreitungsgeschwindigkeit von der Größenordnung 1.4×10^–2 m/s darstellt. Eine derartige Ausbreitung wurde sowohl mit Modellen des Partikel-Tracking als auch mit Modellen der finiten Differenzen reproduziert, wobei die horizontale AusbreitungsgrößeK _H linear von der Diffusionszeit abhängig war. Die Schwäche dieser Methode ist, daß es nicht klar ist, wie die Diffusions-Parameter für andere Wetterbedingungen als zur Zeit des Experiments zu extrapolieren wären. Vergleichbare Ausbreitungsverhältnisse werden durch die Kombination eines Fickschen Diffusionsmodells mit einem advektiven Feld erreicht, welches die oberflächennahen durch Wind und Wellen verursachten Stromscherungen berücksichtigt. Der so resultierende Scher-Diffusions-Effekt erbrachte ein realistische Simulation der beobachteten Ausbreitung. Ein Vorteil dieses Vorgehens ist, daß es Vorhersagen über einen Bereich von Wetterbedingungen ermöglicht, vorausgesetzt, daß die durch Wind und Wellen verurschte Scherung zutreffend parameterisiert werden kann.

---

La dispersion de la panache de surface dans la partie sud de la Mer du Nord

Résumé A partir de déversements continus de produits fluorescents effectués dans la partie sud de la Mer du Nord, on a pu déterminer l'expression de la largeur du panache _y , par son carré en fonction du temps de diffusion. La dispersion n'était pas du type Fickian et était représentée sous la forme _y ² =B ² t aB était une vitesse de diffusion de grandeur égale 1.4×10^–2 m/s. Une telle dispersion peut être reproduite par une modélisation du panache à la fois par suivi de particules et aux différences finies en admettant que le coefficient de diffusion horizontaleK _H dépendait linéairement du temps. L'inconvénient de cette méthode est qu'il n'est pas facile de savoir comment les paramètres de diffusion peuvent être extrapolés à des conditions météorologiques différentes de celles prévalant au moment des expériences. Quoi qu'il en soit, des taux de dispersion comparables ont été obtenus en combinant un modèle de diffusion Fickian avec un champ d'advection qui représentait les cisaillements de courant de surface dus au vent et aux vagues. L'effet de diffusion du cisaillement résultant produisit une simulation réaliste des taux de dispersion observés. Un avantage de cette approche est de rendre possible des prédictions réalisées à travers un éventail de conditions météorologiques à condition que les cisaillements liés au vent et aux vagues puissent être paramétrisés avec précision.

---