Scenarios for eradicating foot-and-mouth disease

Research project commissioned by the Ministery of Agriculture, Nature Management and Fisheries. With the help of desk-research and input-output analysis quantitative information is assembled about the differences in cost for agribusiness and tourism of two eradication scenarios for foot-and-mouth disease. The first scenario was based on the eradication method used in the year 2001, vaccination with culling. The second scenario was based on vaccination without cullin

Ontwikkeling van een instrumentarium voor het bepalen van regionaal-economische effecten van landinrichtingsprojecten. Illustratie aan de hand van de case 'het Kuindermeer'

Wat is het rendement van een landinrichtingsproject? In eerste instantie is zo een project veelal gericht op een bepaald doel: waterberging, recreatie, het verbeteren van de ecologische of agrarische structuur, enzovoort. Maar los van deze overwegingen gaat er van elk project ook een effect uit op de regionale economie. Voor het kwantificeren van dat economische effect is grote belangstelling. Lokale bestuurders willen graag weten hoezeer zo'n project bijdraagt aan de regionaal-economische beleidsdoelstellingen en op nationaal niveau zou men graag weten in welke regio's overheidsimpulsen het meeste effect kunnen sorteren. Vandaar dat de LEI-onderzoeksgroep Ruimtelijke Economische Modellen (REM) ging werken aan een instrumentarium om te meten wat een bepaald project voor invloed zal hebben op de toegevoegde waarde en de werkgelegenheid in een bepaalde regio. Dit op verzoek van de Directie Groene Ruimte en Recreatie van het ministerie van LNV. Bij wijze van voorbeeld werd het ontwikkelde instrumentarium toegepast op twee varianten van het eventueel aan de noordoostflank van de Noordoostpolder te graven 'Kuindermeer'

Adoption of advanced manufacturing technology and firm performance in the Netherlands

This paper presents characteristics of firms which employ advanced manufacturing tech-nology (AMT), explores the pattern of adoption of such technology, and traces the effects ofadoption on the evolution of employment and productivity. The study uses linked firm-leveldata on production, factor inputs and on advanced manufacturing technology. It is foundthat the percentage of firms which employ advanced technology increases with higher laborproductivity, higher export-sales ratios, and especially larger firm size. Corrected for interac-tions, however, only initial size and the capital-labor ratio in 1985 aid in predicting adoptionof AMT. Conditional on adoption of AMT it is seen that intensity of advanced technologyinputs decrease with firm size and with labor productivity. Finally, firms which employedAMT in 1992 show higher average growth rates of employment and of the capital-labor ratiobetween 1985 and 1991

Algorithms to measure diversity and clustering in social networks through dot product graphs.

Social networks are often analyzed through a graph model of the network. The dot product model assumes that two individuals are connected in the social network if their attributes or opinions are similar. In the model, a d-dimensional vector a v represents the extent to which individual v has each of a set of d attributes or opinions. Then two individuals u and v are assumed to be friends, that is, they are connected in the graph model, if and only if a u · a v  ≥ t, for some fixed, positive threshold t. The resulting graph is called a d-dot product graph.. We consider two measures for diversity and clustering in social networks by using a d-dot product graph model for the network. Diversity is measured through the size of the largest independent set of the graph, and clustering is measured through the size of the largest clique. We obtain a tight result for the diversity problem, namely that it is polynomial-time solvable for d = 2, but NP-complete for d ≥ 3. We show that the clustering problem is polynomial-time solvable for d = 2. To our knowledge, these results are also the first on the computational complexity of combinatorial optimization problems on dot product graphs. We also consider the situation when two individuals are connected if their preferences are not opposite. This leads to a variant of the standard dot product graph model by taking the threshold t to be zero. We prove in this case that the diversity problem is polynomial-time solvable for any fixed d

Molecular exchange-correlation Kohn-Sham potential and energy density from ab initio first- and second-order density matrices: examples for XH (X=Li, B,F).

The molecular Kohn–Sham exchange‐correlation potential vxc and the energy density εxc have been constructed from ab initio first‐ and second‐order density matrices for the series XH (X=Li, B, F). The way various effects of electronic structure and electron correlation manifest themselves in the shape of vxc and εxc has been analyzed by their decomposition into various components; the potential of the exchange‐correlation hole, the kinetic component and (in the case of vxc) the ‘‘response’’ component. The kinetic energy of noninteracting particles Ts, the kinetic part of the exchange‐correlation energy Tc, and the energy of the highest occupied molecular orbital εN have been obtained with reasonable accuracy and the effect of bond formation on these functionals has been studied

Environmental Flow Regimes for Dysidea avara Sponges

The aim of our research is to design tank systems to culture Dysidea avara for the production of avarol. Flow information was needed to design culture tanks suitable for effective production. Water flow regimes were characterized over a 1-year period for a shallow rocky sublittoral environment in the Northwestern Mediterranean where D. avara sponges are particularly abundant. Three-dimensional Doppler current velocities at 8¿10-m depths ranged from 5 to 15 cm/s over most seasons, occasionally spiking to 30¿66 cm/s. A thermistor flow sensor was used to map flow fields in close proximity (¿2 cm) to individual sponges at 4.5-, 8.8-, and 14.3-m depths. These ¿proximal flows¿ averaged 1.6 cm/s in calm seas and 5.9 cm/s during a storm, when the highest proximal flow (32.9 cm/s) was recorded next to a sponge at the shallowest station. Proximal flows diminished exponentially with depth, averaging 2.6 cm/s¿±¿0.15 SE over the entire study. Flow visualization studies showed that oscillatory flow (0.20¿0.33 Hz) was the most common regime around individual sponges. Sponges at the 4.5-m site maintained a compact morphology with large oscula year-around despite only seasonally high flows. Sponges at 8.8 m were more erect with large oscula on tall protuberances. At the lowest-flow 14.3-m site, sponges were more branched and heavily conulated, with small oscula. The relationship between sponge morphology and ambient flow regime is discussed

Prohibited Floor Trading Activities Under the Commodity Exchange Act

In algorithmic graph theory, a classic open question is to determine the complexity of the Maximum Independent Set problem on Pt -free graphs, that is, on graphs not containing any induced path on t vertices. So far, polynomial-time algorithms are known only for t≤5 (Lokshtanov et al., in: Proceedings of the twenty-fifth annual ACM-SIAM symposium on discrete algorithms, SODA 2014, Portland, OR, USA, January 5–7, 2014, pp 570–581, 2014), and an algorithm for t=6 announced recently (Grzesik et al. in Polynomial-time algorithm for maximum weight independent set on P6 -free graphs. CoRR, arXiv:1707.05491, 2017). Here we study the existence of subexponential-time algorithms for the problem: we show that for any t≥1 , there is an algorithm for Maximum Independent Set on Pt -free graphs whose running time is subexponential in the number of vertices. Even for the weighted version MWIS, the problem is solvable in 2O(tnlogn√) time on Pt -free graphs. For approximation of MIS in broom-free graphs, a similar time bound is proved. Scattered Set is the generalization of Maximum Independent Set where the vertices of the solution are required to be at distance at least d from each other. We give a complete characterization of those graphs H for which d-Scattered Set on H-free graphs can be solved in time subexponential in the size of the input (that is, in the number of vertices plus the number of edges): If every component of H is a path, then d-Scattered Set on H-free graphs with n vertices and m edges can be solved in time 2O(|V(H)|n+m√log(n+m)) , even if d is part of the input. Otherwise, assuming the Exponential-Time Hypothesis (ETH), there is no 2o(n+m) -time algorithm for d-Scattered Set for any fixed d≥3 on H-free graphs with n-vertices and m-edges

Regionale input-outputanalyse. In welke regio's en sectoren heeft een vraagimpuls het hoogste rendement?

Regionaal-economisch stimuleringsbeleid is gebaat bij kennis over de te verwachten effecten van een vraagimpuls. Deze studie laat zien dat het effect van een economische impuls duidelijk verschilt per regio en per sector. Relatief grote verschillen tussen regio's bestaan met name voor de landbouw en visserij en de industrie en delfstoffenwinning. Investeren in de Randstad heeft gemiddeld gezien minder effect dan in een andere regio van Nederland, vooral vanwege de relatief kleine spin-off. Op grond van deze effectenanalyse kunnen vraagtekens gezet worden bij het huidige regionaal-economische beleid dat met name gericht is op stimulering van sectoren als transport en communicatie (in de Randstad) en de tertiaire en quartaire sector in het algemeen (dienstverlening). Stimulering van sectoren die sterk(er) gericht zijn op de binnenlandse markt en die onderdeel uitmaken of sterk verbonden zijn aan de traditionele primaire en secundaire bedrijfstakken dan op de eerder genoemde sectoren levert meer op

Validity of self-reported causes of subfertility

The authors assessed the accuracy of cause(s) of subfertility as reported by women in a self-administered questionnaire in comparison with medical record information, in a nationwide cohort study of women receiving in vitro fertilization treatment in the Netherlands (n = 9,164) between 1983 and 1995. Validity was expressed as sensitivity and specificity, and reliability was expressed by the kappa statistic and overall agreement between self-reports and medical records for various subfertility categories. The sensitivity for subfertility attributed to tubal, male, hormonal, cervical, uterine, and idiopathic factors and for endometriosis was 84%, 78%, 65%, 40%, 46%, 59%, and 83%, respectively. The corresponding kappas were 0.79, 0.71, 0.38, 0.34, 0.13, 0.50, and 0.52, respectively. For 54% of all women who reported two or more causes of subfertility, the medical record revealed only one major factor. Conversely, for 43% of all women whose subfertility was attributed to two or more major factors in the record, only one factor was reported by the women. Older age at the time of filling out the questionnaire, low educational level, long duration of subfertility, and pre-in vitro fertilization treatment were associated with less accurate reporting. The results indicate that the validity of self-reports for tubal and male subfertility is satisfactory. For unexplained subfertility, the validity is moderate; for other causes of subfertility and when two causes of subfertility play a role, the validity is low. Copyrigh