Working from home and the willingness to accept a longer commute

It is generally found that workers are more inclined to accept a job that is located farther away from home if they have the ability to work from home one day a week or more (telecommuting). Such findings inform us about the effectiveness of telecommuting policies that try to alleviate congestion and transport-related emissions, but they also stress that the geography of labour markets is changing due to information technology. We argue that estimates of the effect of working from home on commuting time may be biased because of sorting based on residential- and commuting preferences. In this paper we investigate the relationship between telecommuting and commuting time, controlling for preference-based sorting. We use 7 waves of data from the Dutch Labour Supply Panel and show that on average telecommuters have higher marginal cost of one-way commuting time, compared to non-telecommuters. We estimate the effect of telecommuting on commuting time using a fixed effects approach, and we show that preference-based sorting biases cross-sectional results upwards. This suggests that the bias due to sorting based on residential preferences is strongest. Working from home allows people to accept 5% longer commuting times on average, and every additional 8 h of working from home are associated with 3.5% longer commuting times.     

A robot to detect and control broad‐leaved dock (Rumex obtusifolius L.) in grassland

Broad‐leaved dock is a common and troublesome grassland weed with a wide geographic distribution. In conventional farming the weed is normally controlled by using a selective herbicide, but in organic farming manual removal is the best option to control this weed. The objective of our work was to develop a robot that can navigate a pasture, detect broad‐leaved dock, and remove any weeds found. A prototype robot was constructed that navigates by following a predefined path using centimeter‐precision global positioning system (GPS). Broad‐leaved dock is detected using a camera and image processing. Once detected, weeds are destroyed by a cutting device. Tests of aspects of the system showed that path following accuracy is adequate but could be improved through tuning of the controller or adoption of a dynamic vehicle model, that the success rate of weed detection is highest when the grass is short and when the broad‐leaved dock plants are in rosette form, and that 75% of weeds removed did not grow back. An on‐farm field test of the complete system resulted in detection of 124 weeds of 134 encountered (93%), while a weed removal action was performed eight times without a weed being present. Effective weed control is considered to be achieved when the center of the weeder is positioned within 0.1 m of the taproot of the weed—this occurred in 73% of the cases. We conclude that the robot is an effective instrument to detect and control broad‐leaved dock under the conditions encountered on a commercial farm. © 2010 Wiley Periodicals, Inc.     

Relation between preparation,porosity and selectivity of CuO-ZnO-MeO x catalysts in the synthesis of alcohol mixtures

Some relations between the preparation of modified CuO-ZnO catalysts, their structural properties and their catalytic performance in the hydrogenation of carbon monoxide have been demonstrated. The different activities in the formation of higher alcohols have been attributed to an influence of the porosity on chain growth. The coupling or insertion of C₁ intermediates seems to be favoured by an increasing surface coverage with C₁ intermediates due to a transport limitation of methanol production. The pore size distribution of the catalysts has been varied by different calcination, thermal ageing, CuO/ZnO ratios, the method of promoting with Al₂O₃ and pelleting.     

Effects of prophylactic vitamin administration of physical fitness of schoolchildren in the Arctic Regions]

The effectiveness of prophylactic vitamin administration to schoolchildren in the Arctic region was evaluated in the biochemical investigation of schoolchildren by the assay of vitamins C, A, E, B1, B2, B6, B12 and folic acid in their blood serum before and after "Undevitum" intake. Deficiency of a number of vitamins was detected. It was shown that regular consumption of multivitamin "Undevitum" produced a positive effect on the parameters of their physical activity, the highest effect was observed in children with the normotensive reaction to loading, and it was less expressed in those with pathological hemodynamic reactions to the loading.     

Watt-1 linkages with shunted chebyshev-dyads,producing symmetrical 6-bar curves

The five “symmetry-conditions” to be met by a non-symmetrical Watt-1 linkage, producing a symmetrical curve, may be derived through a cognate-transfiguration of a symmetrically driven Peaucellier-Lipkin cell (see Figs. 6–8). A further derivation shows that such a curve may also be produced by a Watt-1 linkage containing a “kite-cell” that exists of a 4-bar kite with two isosceles similar triangles attached to adjacent sides of the kite. Such a kite-cell transforms a circle as well as a symmetrical 4-bar coupler curve into a symmetrical 6-bar Watt-1 curve or order 8 (see Figs. 9, 10).     

Highest-order coupler points of Watt-1 linkages, tracing symmetrical 6-bar curves

Certain non-symmetrical Watt-1 linkage mechanisms may produce symmetrical curves. The dimensions of such mechanisms then have to meet five precise conditions. They have been derived from the two possibilities that symmetrize the Assembly Configuration containing the four 6-bar curve cognates. Each possibility leads to a different mechanism. The one that can be driven without additional conditions, contains a kite 4-bar, carrying rigid triangles that are similar and otherwise related. Then, a ‘kite-cell’ is involved, transforming the input-circle into a symmetrical Watt-1 curve of the 8th or of the 12th degree, depending on the choice of coupler-plane. The second possibility leads to a mechanism in which not only a point, but also a straight-line reaches the image positions. This type, however, must move through a ‘stretched position’ with a two-fold coupler motion. Then, gear-pairs or the like are necessary to overcome such a bifurcated position.     

Strategic Planning for City Networks: The Emergence of a Basque Global City?

Throughout Europe, policy-makers recognize the development potentials of regions in which multiple cities are located close to each other. However, developing synergies among these cities requires networking to optimize the critical mass and exploit complementarities. Much is expected of spatial planning in terms of fostering networks. However, little is known about the actual contribution planning may have in developing city networks, in particular, since it involves planning on a new scale and based upon new starting points and objectives. Exemplary is the territorial development strategy (1990s) of the Basque country aimed at developing the networking among its three main cities (Bilbao, San Sebastian and Vitoria) to develop a Basque ‘Global City’. We find that the leverage of this planning strategy has been poor, due to strong local identities and the lack of regional organizing capacity. This also appears to be common for other polycentric regions.