Local government web sites in Finland: A geographic and webometric analysis

It has been shown that information collected from and about links between web pages and web sites can reflect real world phenomena and relationships between the organizations they represent. Yet, government linking has not been extensively studied from a webometric point of view. The aim of this study was to increase the knowledge of governmental interlinking and to shed some light on the possible real world phenomena it may indicate. We show that interlinking between local government bodies in Finland follows a strong geographic, or rather a geopolitical pattern and that governmental interlinking is mostly motivated by official cooperation that geographic adjacency has made possible.     

Litterfall production and associated carbon and nitrogen fluxes of seven woody species grown in indigenous agroforestry systems in the south-eastern Rift Valley escarpment of Ethiopia

We compared the litterfall production and associated carbon (C) and nitrogen (N) fluxes for seven woody species grown in three agroforestry systems practiced on the slopes of the south eastern Rift Valley escarpment of Ethiopia. Five of the species were native (Coffea arabica L., Cordia africana Lam., Croton macrostachyus Del., Erythrina brucei Schweinf. and Millettia ferruginea (Hochst.) Bak) and two were non-native fruit tree species (Mangifera indica L. and Persea americana Mill.). Together, these species accounted 85 % or more of the crown area of each agroforestry system: the Enset system (occurring at 2,100–2,400 m asl), the Enset-Coffee system (1,900–2,200 m asl), and the Fruit-Coffee system (1,500–1,900 m asl). Enset or false banana [Ensete ventricosum (Welw.) Cheesman] is a staple food crop in this region of Ethiopia and coffee and fruit trees are grown as cash crops. Monthly litterfall was collected from 4 to 6 trees of each species during 2010 and dry mass, carbon and nitrogen contents determined. The annual litterfall production per unit area of crown decreased in the order: C. macrostachyus (1,014 g m^?2), E. brucei (929), C. africana (917), P. americana (809), M. indica (807), C. arabica (446) and M. ferruginea (362). The simple linear regression equation using breast height diameter explained 95 % of the variation in the litterfall production of M. ferruginea, but only 55 % for C. africana. The annual litterfall production of the seven species combined per unit area of land was the highest for the Fruit-Coffee system (average 12,938 kg ha^?1), followed by the Enset-Coffee system (10,187) and the Enset system (7,430). The associated annual C fluxes (kg ha^?1) were 5,145 (Fruit-Coffee system), 3,928 (Enset-Coffee system) and 2,803 (Enset system), and corresponding N fluxes 278 (kg ha^?1), 257 and 190. The combined litterfall production of the seven species in our study was higher than has been reported for other agroforestry systems and tropical forests.     

The sensitivity of estimates of regression to the mean

Estimations of the effectiveness of remedial treatments in road safety analysis are frequently bedevilled by the problem of regression to the mean (RTM). The number of accidents x observed at a site in the “before” period is a “noisy” quantity: x is Poisson distributed about an (unknown) true mean m for that site, so that x = m + e. Sites selected for treatment tend to have a positive random error component e, which will on average be zero in the “after” period, even if no treatment is applied.Methods for estimating RTM usually require some assumption about the underlying (prior) between-site distribution of the true means f₀(m): for example, in the empirical Bayes method, a gamma distribution is assumed. The paper considers the impact of different assumptions for this distribution and, indeed, whether any distributional form needs to be assumed. Using Markov Chain Monte Carlo methods, a variety of distributional forms are assumed for f₀(m) and applied to each of a number of real data sets, including that from a major study on the effectiveness of speed cameras. It is shown that, in some cases, the size of the estimated RTM effect can be quite sensitive to the choice of distribution.     

Numerical modelling of wind flow over a complex topography

Numerical modelling of wind flow over complex dune topography is an ambitious prospect. There is an increasing need to understand wind flow over complex topography for land planning purposes to enable prediction of sediment transport at a particular site. New surveying techniques permit the rapid development of digital terrain models, however a stumbling block is the ability of Computational Fluid Dynamics (CFD) to emulate the wind flow over such a landscape. To overcome these difficulties, it is important to establish the parameters within which such simulations can operate. This paper details an initial two-dimensional numerical model developed in order to test various modelling assumptions against experimental field wind data. Mason Bay, Stewart Island, New Zealand was chosen as an undisturbed but accessible experimental site with a prevalent on-shore wind perpendicular to a simple foredune and a complex down-wind parabolic dune system. A complex topographical two-dimensional model with vegetation represented as a roughness was compared against field data along a transect dissecting a dune system.This paper establishes that:

* Replicating the roughness patterns at the surface is important

* The inlet profile should be duplicated with care

* Modelling only a portion of the domain can have an effect on the flow patterns due to outflow effects

* There is a modelling decision to be made between the complexity of the topography and the sophistication of the turbulence model and degree to which vegetation and sand transportation are modelled.

The long-term aim is to instil confidence in numerical techniques so that such technology can be used for predictive purposes.     

Book reviews

Australian Environmental Policy 2: Studies in Decline and Devolution

Ken Walker and Kate Crowley (eds) UNSW Press, Sydney, 1999 ISBN 0868406732 (paperback) 323 pp.; bibliography and index RRP $35.00

Beyond Meltdown: The Global Battle for Sustained Growth.

Peter Brain. Scribe, Melbourne, 1999 ISBN 0908011369 (paperback) 273 pp.; bibliography and index RRP $26.95

Cities Back from the Edge: New Life for Downtown

Roberta Brandes Gratz with Norman Mintz John Wiley & Sons, New York, 1998 ISBN 0471144177 (hardback) 347 pp.; index RRP $59.95

Evaluation in Planning: Facing the Challenge of Complexity

Nathaniel Lichfield, Angela Barbanente, Dino Bori, Abdul Khakee and Anna. Prat (eds). Kluwer, Dordrecht, 1998. ISBN 0792351770 (hardback). 383 pp.; index. RRP $254.00

Gritty Cities: Images of the Urban

Lyaranette Finch and Chris McConville (eds). Pluto, Sydney, 1999. ISBN 1864030631 (paperback). 250 pp.; bibliography and index. RRP $24.95

Setting the Stage for Systainability: A Citizen's Handbook

Chris Maser, Russ Beaton and Kevin Smith Lewis Publishers, Boca Raton, 1998 ISBN 1574441876 (hardback) 269 pp.; index RRP $47.50

The Australian Metropolis: A Planning History

Stephen Hamnett and Robert Freestone (eds) Allen & Unwin, Sydney, 1999 ISBN 1865080535 (paperback) 229 pp.; index RRP $35.00     

用FPGA设计引擎安全监测仪实现创业

并非只有宇宙才诞生于大爆炸。目前硅谷最火的汽车电子新创企业PLX Devices也诞生于创始人的引擎爆炸。PLX最新的产品是一款能够监测汽油使用状况，鼓励节油驾驶的插入式器件。它源自公司28岁的首席执行官Paul Lowchareonkul在驾车与奔驰赛车跑坏了引擎后发明的一个空气燃油比测量仪。这两款器件均采用了赛灵思FPGA平台。     

Effect of soluble fibre (guar gum and carboxymethylcellulose) addition on technological, sensory and structural properties of durum wheat spaghetti

Incorporation in pasta of either of two soluble fibres, carboxymethylcellulose sodium salt (CMC) and guar gum (GG), was found to significantly reduce the rate of invitro starch digestion. The amount of reducing sugars produced over 300 min was reduced by 18% at 1.5% CMC incorporation and 24% at 20% GG incorporation. Negative effects on sensory and technological properties were seen at the high levels of GG needed to reduce the rate of in vitro digestion, and a ‘matty’ layer covering the surfaces of starch granules was observed by scanning electron microscopy and confocal scanning laser microscopy. By contrast, levels of CMC incorporation giving large reductions in in vitro digestion had no negative effects on pasta properties. No significant alteration in pasta structure on CMC incorporation was observed by microscopy. The large difference in the amounts of soluble fibre required to bring about equivalent reductions in digestion rate suggests that different mechanisms may be involved in the two cases.