Poaceae phytoliths from the Niassa Rift,Mozambique

The most common grass phytoliths from “Zambezian” miombos are described here for the first time. Their potential for long term preservation in sediments makes them a useful tool in the reconstruction of ancient plant communities and plant/human interactions. We processed 60 plant samples (26 identified genera and species), with an average of 300 phytoliths counted per sample to a total of 18,586. Forty-seven morphotypes were described as per the International Code for Phytolith Nomenclature, with exceptions, including forty-five discreet shapes and two articulated forms, which can be used as comparative reference materials. We conducted three forms of statistical analyses: Discriminant Analysis, Cluster Analysis, and Principal Component Analysis. The highest biomineral content was recorded among the Bambuseae and Paniceae, while the lowest silica production is detected in the Cynodonteae tribe. Typologically, the subfamily Panicoideae yielded 50% of the types reported here, 32% are from the Chloridoideae, 12% from the Bambusoideae, and 8% from the Arundinoideae sensu lato. Overall, the idealized Zambezian Poaceae phytolith spectrum is dominated by a small subset of Poaceae short cells, which include five morphotypes conventionally associated with Panicoid grasses (Bilobate concave outer margin long shaft, Bilobate concave outer margin short shaft, Bilobate convex outer margin long shaft, Bilobate convex outer margin short shaft, Cross), one morphotype commonly seen in Chloridoid taxa (saddle), and two types that appear across subfamily boundaries (tower, tower horned). The next logical step to take in regional phytolith research is the account of phytoliths deposited in soils underneath living plants, for they represent the interface between existing vegetation communities and the inevitably distorted fossil assemblages that the paleobotanist uses for environmental reconstruction.     

NAFTA's Impact on Business Environmental Decision Making

Signing the North American Free Trade Agreement (NAFTA) liberalized trade policy and reduced tariffs between Mexico, the United States, and Canada, but activists opposed to the treaty predicted an environmental disaster. This article seeks to analyze the dynamics of environmental spending and changes in companies' profiles following NAFTA. Our results suggest that these predictions have not come true. Through an econometric model, we explore how 2,438 industries in the 1994–2002 period made environmental decisions and how much they spent on cleanup. Estimates were made with a dynamic panel model using the generalized method of moments (GMM) method. Our results suggest that environmental investment decisions depended on business size, their technological capabilities, sales performance, and the need to comply with the standards required by customers in the international market. The last section explores policies to improve compliance with Mexico's environmental regulations and to develop sustainable, eco‐friendly manufacturing.     

Out of the outhouse: The impact of place‐based policies on dwelling characteristics in Appalachia

The Appalachian Regional Commission (ARC) administers and partially funds investment projects designed to improve economic conditions in the Appalachian region, an area of persistent poverty and reduced economic opportunity in the eastern United States in and around the Appalachian mountains. Previous research on the effectiveness of ARC programs is mixed. We analyze the impact of ARC investment projects related to expanding sewerage and waste water treatment on dwelling characteristics. Results from a difference‐in‐differences model using a quasi‐experimental approach show that ARC investment projects improved access to running water, and increased sewer hookups and indoor bathrooms in dwellings.     

The Geography of the Mathematics Research Collaboration Graph

Social networks have become a hot topic for research in the last decade or so. I study one such network in considerable detail: the graph of research collaborations among mathematicians. This graph displays many of the characteristics that various authors have found common to social networks in general. My “geographical” analysis includes the size of this graph, the distribution of the degrees of its vertices, its connectivity, the distances between its vertices, and its clustering coefficient. I also discuss the playful concept of Erd?s numbers. Las redes sociales se han convertido en un tema de gran interés de investigación durante la última década más o menos. El autor analiza una de esas redes a detalle: el grafo de las colaboraciones de investigación entre matemáticos. Este grafo muestra muchas de las características comunes que varios autores han encontrado en redes sociales en general. El análisis “geográfico” incluye el tamaño de este grafo, la distribución de los grados de sus vértices, su conectividad, las distancias entre sus vértices, y su coeficiente de concentración o clustering. El estudio también trata el concepto lúdico de los números de Erdos. 社会网络已成为近十年来研究的热点。作者详尽地研究了数学家间研究合作图。该图显示了不同作者间常拥有一般社会网络共有的许多特性。本文的地理分析包括图的大小、顶点的分布度与连结性,不同边之间的距离以及聚类指数。同时还讨论了有趣的Erd?s 数的概念。     

Northern Samaria: A Process-Pattern Analysis of Rural Settlement

In northern Samaria, Arab settlement has expanded by a process of colonization from parent villages during the past century. The changes in settlement patterns were analysed and the relative tendencies for randomness, regularity, and clustering were then estimated by variance/mean ratios, to test whether the settlement process can be explained by Hudson's three-stage model for rural settlement. No definite answer could be given, because the effects of soils and terrain were dominant in all parts of the area, but the finding that the settlements tend to be grouped even in the initial stage suggests that Hudson's theory is inadequate.
Au nord de la Samarie, la colonisation Arabe s'est étendue par un processus de colonisation de villages parents pendant le dernier siècle. Les changements dans les forms de colonisations ont été analysés et les tendances relatives pour caractère de regularité, caractère à l'aléatoire, et caractère d'accumulation ont allors été estimées par proportions de variation/moyenne, pour examiner si le processus de colonisation par trois phases de Hudson peut être expliqué pour le modèle de colonisation rurale. Une réponse définitive n'a pas pu être donnée parce que les effets de sol et reliefs étaient dominants dans toutes les parties des environs, mais le résultat que les colonisations ont tendance de se grouper même dans la phase initiative suggère que la théorie de Hudson est inadéquate.     

The character of a global transport infrastructure: Jules Verne’s Around the World in Eighty Days

Jules Verne’s Le Tour du monde en quatre-vingts jours, serialized in 1872 and published in English in 1874 as Around the World in Eighty Days, displays through its hero the character, in both senses of the term, of the new global public transport system that had transformed long-distance travel in the nineteenth century. Verne’s fiction imagines the community defined by this system in three particular elements: A high-speed public transport network creates a community of people by extending their synchronic collective sense of ongoing separate simultaneous activity and, collaterally, unifies them historically as contemporaries defined by the current mode, form and speed of their transport network; it creates this community of people irrespective of the individual purposes for which they use the transport system; and individuals comprehend this networked community by projecting an omniscient-like perspective through which they imagine themselves and others as circulating bodies in it.