Taxonomic revisions of some Upper Cambrian and Lower Ordovician Conodonts with comments on their Evolution

39 p. 6 fig., 2 pl.http://paleo.ku.edu/contributions.htm

Complexity, Collective Effects and Modelling of Ecosystems: formation, function and stability

We discuss the relevance of studying ecology within the framework of Complexity Science from a statistical mechanics approach. Ecology is concerned with understanding how systems level properties emerge out of the multitude of interactions amongst large numbers of components, leading to ecosystems that possess the prototypical characteristics of complex systems. We argue that statistical mechanics is at present the best methodology available to obtain a quantitative description of complex systems, and that ecology is in urgent need of ``integrative'' approaches that are quantitative and non-stationary. We describe examples where combining statistical mechanics and ecology has led to improved ecological modelling and, at the same time, broadened the scope of statistical mechanics.Comment: 11 pages and 1 figur

Subgroups of direct products of limit groups

If $G_1,...,G_n$ are limit groups and $S\subset G_1\times...\times G_n$ is of type \FP_n(\mathbb Q) then $S$ contains a subgroup of finite index that is itself a direct product of at most $n$ limit groups. This settles a question of Sela.Comment: 20 pages, no figures. Final version. Accepted by the Annals of Mathematic

On the finite presentation of subdirect products and the nature of residually free groups

We establish {\em{virtual surjection to pairs}} (VSP) as a general criterion for the finite presentability of subdirect products of groups: if $\Gamma_1,...,\Gamma_n$ are finitely presented and $S<\Gamma_1\times...\times\Gamma_n$ projects to a subgroup of finite index in each $\Gamma_i\times\Gamma_j$, then $S$ is finitely presentable, indeed there is an algorithm that will construct a finite presentation for $S$. We use the VSP criterion to characterise the finitely presented residually free groups. We prove that the class of such groups is recursively enumerable. We describe an algorithm that, given a finite presentation of a residually free group, constructs a canonical embedding into a direct product of finitely many limit groups. We solve the (multiple) conjugacy problem and membership problem for finitely presentable subgroups of residually free groups. We also prove that there is an algorithm that, given a finite generating set for such a subgroup, will construct a finite presentation. New families of subdirect products of free groups are constructed, including the first examples of finitely presented subgroups that are neither ${\rm{FP}}_\infty$ nor of Stallings-Bieri typeComment: 44 pages. To appear in American Journal of Mathematics. This is a substantial rewrite of our previous Arxiv article 0809.3704, taking into account subsequent developments, advice of colleagues and referee's comment

Ireland Dear Ireland

https://digitalcommons.library.umaine.edu/mmb-vp/4977/thumbnail.jp

Habitat, the New United Nations Initiative in Human Settlements

Habitat, the synonym for the United Nations Center for Human Settlements, is a new UN agency with a staggering mandate. Its charge is to assist developing nations in settlement policy and planning, in slum upgrading, urban renewal, and in the development of shelter materials. The upgrading of infrastructural services, such as those involving finance, loans, building codes, and regulatory laws, are a part of the mandate, as are such basic elements as clean water, electricity, and sewage removal. Still further, the agency, which is headquartered in Nairobi, Kenya, is charged with helping generate rational land-use policies, gaining public participation, and helping build local management institutions that attack settlement problems. Given that the world will have to double the size of its built environment by the year 2000, and that currently 60 percent of the world is unsheltered or housed inadequately, Habitat does indeed face an awesome challenge

Oxandrolone Treatment in Adults with Severe Thermal Injury

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90285/1/phco.29.2.213.pd

Hypothesized Cambrian medusae from Saint John, New Brunswick, reinterpreted as sedimentary structures

More than a hundred radial and discoidal structures occur on bed tops of shales and very fine sandstones of the Cambrian (Series 3) King Square Formation in New Brunswick, Canada. These structures typically contain a central sediment plug, radial lineations that extend outward from the central plug, concentric rings, and a broad trough surrounding or underlying ring margins. Originally interpreted as fossils of scyphozoan medusae, these structures could represent one of only a half-dozen mass strandings documented from the fossil record. Instead, re-evaluation of their sedimentology and morphology suggests that they are likely sedimentary structures known as Astropolithon. These sand-volcano-like structures formed by subsurface blistering, cracking, and failure of a near-surface or surface bed, triggered by the upward movement of gases or other fluids from underlying beds. RÉSUMÉ Plus d’une centaine de structures radiales et discoïdes apparaissent au sommet des couches de schiste et de grès très fins de la formation King Square du Cambrien (Série 3), du Nouveau-Brunswick, au Canada. Ces structures contiennent généralement un culot sédimentaire central, des linéaments radiaux qui se déploient vers l’extérieur à partir du culot central, des anneaux concentriques, et une vaste cuvette qui ceinture le bord des anneaux ou qui se trouve en dessous. On estimait initialement qu’il s’agissait de méduses scyphozoaires, mais ces structures pourraient correspondre à l’une de la demi-douzaine d’échouages massifs de l’ichnofaune dont les vestiges fossiles ont été retrouvés. La réévaluation de leur contexte de sédimentation et de leur morphologie porte plutôt à croire que ce sont vraisemblablement des structures sédimentaires connues sous le nom d’astropolithon. Ces structures apparentées à un volcan de sable ont été formées par l’apparition d’alvéoles souterraines, le fendillement et la rupture d’une couche près de la surface ou à la surface, et qu’aurait provoquée le déplacement vers la surface de gaz ou d’autres fluides provenant des couches inférieures. [Traduit par la redaction