The spatial ecology of deer–vehicle collisions

Deer–vehicle collisions (DVCs) are a constant problem in North America that cost millions of dollars of damage and loss of human life. This study investigated the spatial relationship of DVCs for a county in western Indiana using nearest neighbor analysis, chi-square test of independence, and a landscape metric: the percentage of like adjacencies. The study was able to show that DVCs are not randomly located, and that habitat type and structure may play an important role in the location of DVCs.     

Organizational Dynamics of the U.S. Logistics Industry: An Economic Geography Perspective*

Although the logistics industry provides critical services to all sectors of the economy, few studies exist in economic geography that examine and explain the organizational dynamics of this industry. This article highlights the significance of the logistics industry in contemporary industrialization and argues that an enriched understanding of the interaction between technology and space can be achieved by examining the evolution of an industry that plays a central role in the contemporary economy. We focus on dimensions that are identified as particularly important: organizational, geographic, and risk and security.     

Examining locally driven climate change policy efforts in three Pacific states

Local jurisdictions play a critical role in climate change mitigation and adaptation. This study analyzes the theoretical framework of locally driven climate change actions and uses geographic information system (GIS) to map local jurisdictions’ climate change policy efforts in three Pacific states - California, Oregon, and Washington. The results of our study indicate statistically significant differences in geographic clusters and variations across jurisdictions. An Ordinary Least Squares (OLS) regression model was used to examine climate risk, emission stress, and socioeconomic context variables to detect influence on local climate change policy efforts. The explanatory results indicate that coastal proximity, population density, vehicles emission, and education variables significantly influence local jurisdictions’ climate change actions. The findings contribute to local organizational decision model research and can help local communities to develop more effective climate change policies.     

Temporal changes of diatoms in marine biofilm developed on acrylic panels submerged in a tropical coast

The colonization of diatom groups on the acrylic panels submerged in Kudankulam coastal waters, east coast of India, was studied for one year from October 2004 to August 2005. Results showed temporal variability in the abundance of dominant diatom groups. Diatoms belonging to 19 genera colonized the panels. Navicula and Nitzschia were the dominant diatoms observed throughout the present study. The abundance of diatoms on test panels increased with the length of exposure. Significant variations in the abundance of Navicula and Nitzschia were observed between the sampling months. Temporal changes in biofilm diatom community composition in this study attain significance from the view point of macrofouling community recruitment on marine structures.     

Protecting small cetaceans from coastal development: Impact assessment and mitigation experience in Hong Kong

Since the early 1990s, there has been an active program in Hong Kong to manage and protect local populations of small cetaceans from the effects of massive development in the area. This paper reviews the progress that has been made. Only two species regularly occur there: the Indo-Pacific humpback dolphin and the finless porpoise. Because most development has occurred in the western waters of Hong Kong, where generally only the humpback dolphin occurs, most of the work has been conducted on that species. Development of large infrastructure projects (such as airports, bridges, expressways, power plants, fuel facilities, and container ports) in Hong Kong often results in land reclamation, dredging and dumping of spoils, pipe and cable laying, percussive and bored piling work, underwater blasting, large increases in vessel traffic, and other impacts. Several mitigation measures have been used with varying levels of success, including bubble curtains/jackets, exclusion zones, ramping up of piling hammers, acoustic decoupling of noisy equipment, vessel speed limits, no-dumping policies, and silt curtains. Baseline, construction-phase, and operational-phase cetacean monitoring is often conducted to evaluate the success of conservation measures put into place. The Environmental Impact Assessment process in Hong Kong has involved cetaceans to a degree perhaps higher than anywhere else in the world, and much can be learned from studying the successes and failures of this situation.     

A new look at the phenomenon of offshore pile plugging

Abstract

Open‐pipe piles are widely used for offshore structures. During the initial stage of installation, soil enters the pile at a rate equal to the pile penetration. As penetration continues, the inner soil cylinder may develop sufficient frictional resistance to prevent further soil intrusion, causing the pile to become plugged. The open‐ended pile then assumes the penetration characteristics of a closed‐ended pile. The mode of pile penetration significantly alters the soil‐pile interaction during and after installation. This affects the ultimate static bearing capacity (mainly in granular materials), the time‐dependent pile capacity (in clays), and the dynamic behavior and analysis of the piles.

Following a summary demonstrating the effects of pile plugging, a review of the common view of offshore pile plugging is undertaken. The interpretation of plugging by referring to the average plug length has led to the erroneous conclusion that in most piles significant plugging action does not occur.

Establishment of an analogy between soil samplers and open‐ended piles enabled correct identification of plugging by referring to the incremental changes in plug length. Examination of case histories of plugging of offshore piles revealed that beyond a certain penetration depth‐to‐diameter ratio, most piles are plugged.     

Zur Struktur der Niederschläge. III

Zusammenfassung Die an acht Stationen von der Polar-bis zur Tropenzone vermessene Struktur des Niederschlags wird hauptsächlich durch die atmosphärische Schichtung und die geographische Lage bestimmt. Dabei treten für die einzelnen Stationen charakteristische Schwankungen auf, die sich z. B. in der Anzahl der Tropfen für die verschiedenen Größengruppen oder in der Breite der Spektren zeigen. Stau- und Labilitätsregen unterscheiden sich deutlich. Für Karlsruhe lassen sich aus den in zeei Jahren gemessenen Daten die Unterschiede von Jahreszeit zu Jahreszeit ableiten. Intensive Regen sind mit Labilität und hoher Temperatur gekoppelt und fehlen deshalb in der Polarzone vollständig. Sie treten außerdem nur bei breiten Spektren auf und sind nur in der Tropenzone an hohe Tropfenzahlen gebunden. Zwischen einem idealen Regen und den tatsächlich vermessenen ergeben sich infolge der immer vorhandenen verschieden großen Tropfen (Spektrum) Unterschiede. Aus der gemessenen Struktur des Regens läßt sich die Radarreflektibilität berechnen. Sie weicht ebenfalls infolge der Spektrenbreite erheblich vom idealen Regen ab und schwankt von Station zu Station. Dabei ist es gleichgültig, ob der mittlere Tropfendurchmesser, die Spektrenbreite, der Wassergehalt oder die Intensität des Regens als Parameter gewählt werden. Ganz allgemein ist die Intensität der vermessenen Regen bis um den Faktor 5 kleiner als die eines entsprechenden idealen Regens. SchließLich gibt der zeitliche Ablauf der einzelnen Regen Beispiele für die Zunahme der Schwankung aller Parameter mit größer werdender Intensität des Regens und für die Schwierigkeit, aus Radarbeobachtungen sicher die Intensität der zu erwartenden Niederschläge vorherzusagen.

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Summary The structure of precipitation, which has been measured at eight stations distributed from the polar to the tropic zone, is mainly determined by the atmospheric stratification and by the geographical situation. Characteristic variations could be found at the different stations, which show up in the number of drops within the various classes of drop sizes or in the range of the spectrum. Rains caused by barrage or by lability are distinctly different. For Karlsruhe one can derive seasonal variations from the data collected in two years. Intense rains are combined with lability and high temperature and, therefore, are absent in the polar zone. Besides this they appear only with broad spectra and are bound to large numbers of drops only in the tropics. Between an ideal rainfall and a really measured one there are always differences on account of the drops of different sizes which always appear (spectrum). From the observed structure of a rain one can derive its radar-reflectivity. Owing to the range of the spectrum it deviates largely from the reflectivity of the ideal rain, too, and differs from station to station. All this does not depend on whether one selects the mean drop diameter, the range of the spectrum, the water contents or the intensity of the rain as parameter. Generally, the intensity of the observed rain is up to five times smaller than the intensity of the corresponding ideal rain. Finally, the temporal progress of the single rains presents examples of the increase of the variation of all parameters with increasing intensity of the rain, and of the difficulty to predict correctly the intensity of the expected precipitation from radar observations.

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Résumé La structure des précipitations de 8 stations échelonnées de la zone polaire aux tropiques est déterminée en majeure partie par la stratification atmosphérique et la position géographique de la station d'observations elle-même. On constate cependant pour chaque station des variations caractéristiques qui se signalent par exemple dans le nombre de gouttes des différents groupes de grosseur ou dans la largeur du spectre. Les pluies de barrage ou d'instabilité sont nettement différentes les unes des autres. Ainsi, pour Karlsruhe, on peut déduire les différences saisonnières des deux seules années d'observations. Les pluies de forte intensité sont liées à de l'instabilité et à de hautes températures. Elles manquent de ce fait totalement dans la zone polaire. Elles ne se rencontrent en outre que pour de larges spectres de gouttes et ne sont liées à de grands nombres de gouttes que dans la zone tropicale. Par suite du fait que les gouttes ont toujours des grandeurs différentes (spectre des gouttes) on constate toujours des différences entre une pluie idéale et celle qui est effectivement mesurée. On peut calculer la réflexion radar en partant de la structure mesurée de la pluie. Elle s'éloigne également de façon sensible de celle d'une pluie idéale par suite de la largeur du spectre des gouttes et varie de station à station. Dans ce cas, il est indifférent que l'on choisisse comme paramètre le diamètre moyen des gouttes, la largeur du spectre, la contenance en eau du nuage ou l'intensité de la pluie. D'une manière toute générale, l'intensité mesurée de la pluie est jusqu'à 5 fois plus faible que celle d'une pluie idéale correspondante. Enfin, l'évolution dans le temps des différentes chutes de pluie donne des exemples de l'augmentation des variations de tous les paramètres avec l'augmentation de l'intensité de la pluie et de la difficulté de prévoir avec précision l'intensité des précipitations au moyen d'observations faites au radar.

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Mit 23 Abbildungen     

Response of juvenile lemon sharks, Negaprion brevirostris, to a magnetic barrier simulating a beach net

Beach nets are preventative devices used to minimize interactions between potentially harmful sharks and unsuspecting swimmers. Quantitative studies demonstrated that beach nets drastically reduced local elasmobranch populations, as well as caused considerable bycatch mortality. For this experiment, a beach net-like device was constructed and the behaviors of six juvenile lemon sharks (Negaprion brevirostris) were analyzed. Induced by olfactory and gustatory cues, sharks were given the choice to swim through a magnetic or control opening in the net. In the first trial, all six sharks avoided the magnetic region and significantly preferred to swim through the control region of the fence. The magnetic stimulus no longer affected the swimming behavior of three sharks retested after resting 24 h. Results from the retested sharks were correlated with those from repeated tonic immobility trials, which demonstrated a linear decrease in sensitivity to repeated magnetic stimulation. This study serves as a baseline experiment demonstrating that permanent magnets may substantially decrease elasmobranch mortality within beach nets.