Search results for "Horizon"

Quick and Slow Components of the Hydrologic Response at the Hillslope Scale

2016

It is widely recognized that the Hortonian mechanism of runoff generation occurs in arid and semi-arid regions, generally characterized by high rainfall intensity on soils exhibiting low infiltrabilities. Differently, in steeply sloping forested watersheds in humid climates, by infiltrating through a highly permeable upper soil horizon, water moves beneath the soil surface determining a slow response. However, in most real cases, for example when in arid regions mountain forested areas take place, both (quick and slow) runoff generation processes coexist and together contribute to the hydrologic hillslope response. In this paper, based on analytical solutions of the hydrologic response, ins…

Wastewater Reuse Effects on Soil Hydraulic Conductivity

2004

The wastewater total suspended solids (TSS) concentration effects on the saturated hydraulic conductivity, \iK\ds, of a clay and a loam soil were investigated on laboratory repacked soil cores by a constant head permeameter. Both municipal wastewater (MW) and artificial wastewater (AW) with different TSS concentrations were used, with the aim to evaluate, by comparison, the effects of biological activity. The development of a surface sealed layer was investigated in loam soil columns supplied with AW and equipped with water manometers at different depths to detect the hydraulic head gradient changes. In the loam soil, \iK\ds reduced to about 80% of the initial value after infiltration of 17…

El sistema regional de innovación de la Comunidad Valenciana: Una aproximación desde las política de la Unión Europea

2016

El presente informe está indicado para realizar una primera aproximación al ámbito de la investigación, el desarrollo y la innovación con el fin de proporcionar al lector una visión global sobre la teorización académica de estos conceptos. El trabajo está estructurado de forma que en primer lugar permita comprender el contexto de la UE en el S.XXI y la importancia adquirida de la innovación en el desarrollo de la economía, para posteriormente dar a conocer de forma general qué políticas públicas se han desarrollado en torno a este nuevo concepto. Seguidamente, se hará una explicación particular de la política europea de subvenciones en I+D+i a través de los fondos estructurales y los progra…

A complex network analysis of inbound tourism in Sicily

2019

In this article, the complex dynamics of inbound tourism in Sicily is analyzed for the period 1998–2017. The horizontal visibility graph algorithm is used to transform the overnight stays' time series into a network whose topology is investigated by standard network analysis. Discontinuities in the domestic and international tourism demand were identified in order to detect signals of change and the timing of the directional change in tourism growth. The network degree distribution confirms the complex structure of the destination and reveals the random and thus more unpredictable nature of the international tourism demand in Sicily, compared with a more stable domestic segment. Some policy…

¿Comienza el deshielo? / 1

2008

Dissipation and distribution of atrazine, simazine, chlorpyrifos, and tetradifon residues in citrus orchard soil.

1997

An environmental fate study was conducted in a citrus orchard plot in Valencia (Spain) in the fall of 1993. Dissipation and distribution of atrazine, simazine, chlorpyrifos and tetradifon residues following their controlled addition for agricultural purposes in a mediterranean red soil (Luvic Calcisol, Rhodoxeralf) were evaluated. During a two-month period, the amounts of applied pesticides in different soil layers (0-0.05, 0.05-0.22, 0.22-0.42, and 0.42-0.52 m) were monitored. In addition, information on soils, weather and agricultural practice were collected. Degradation half-lives were calculated, assuming zero-order kinetics: 11 days for atrazine, 12 days for simazine, 10 days for chlor…

European administrative centre formation. Lessons from international bureaucracies

2011

The strengthening of administrative powers is comprehensively documented within national governments. This article asks to what extent centre formation also happens within international bureaucracies. Based on a large body of data (N=121) within three international bureaucracies, this study adds two new observations: First, administrative centre formation is primarily observed inside the European Commission and only marginally within other international bureaucracies – such as the OECD and WTO Secretariats. Moreover, within the Commission, centre formation is primarily observed at the administrative centre (the General Secretariat) and only marginally within bureaucratic sub-units. Concomit…

Cooperative Inventory control

2005

In multi-retailer inventory control the possibility of sharing setup costs motivates communication and coordination among the retailers. We solve the problem of finding suboptimal distributed reordering policies that minimize setup, ordering, storage, and shortage costs incurred by the retailers over a finite horizon. Neuro-dynamic programming (NDP) reduces the computational complexity of the solution algorithm from exponential to polynomial on the number of retailers.

Boolean-controlled systems via receding horizon and linear programing

2009

We consider dynamic systems controlled by boolean signals or decisions. We show that in a number of cases, the receding horizon formulation of the control problem can be solved via linear programing by relaxing the binary constraints on the control. The idea behind our approach is conceptually easy: a feasible control can be forced by imposing that the boolean signal is set to one at least one time over the horizon. We translate this idea into constraints on the controls and analyze the polyhedron of all feasible controls. We specialize the approach to the stabilizability of switched and impulsively controlled systems.

Structure and evolution of the leucine plasmids carried by the endosymbiont (Buchnera aphidicola) from aphids of the family Aphididae.

1998

In all examined species of the family Aphididae, the bacterial endosymbiont Buchnera aphidicola carries a plasmid encoding the genes leuABCD (involved in leucine biosynthesis) along with repA1, repA2 and ORF1. The gene organisation of the leucine plasmids was conserved, except in Buchnera isolated from Pterocomma populeum, where ORF1 was located in a different position. An inverted repeat (LIR1) located between repA2 and leuA is found in all of the Buchnera leucine plasmids examined. The predicted secondary structure of the LIR1 transcript conforms to a long hairpin loop, suggesting an involvement in transcription termination or messenger stability. Phylogenetic reconstruction based on repA…