University of Antwerp

About: University of Antwerp is a education organization based out in Antwerp, Belgium. It is known for research contribution in the topics: Population & Context (language use). The organization has 16682 authors who have published 48837 publications receiving 1689748 citations. The organization is also known as: Universiteit Antwerpen & UAntwerp.

Port regionalization: towards a new phase in port development

Abstract: Logistics integration and network orientation in the port and maritime industry have redefined the functional role of ports in value chains and have generated new patterns of freight distribution and new approaches to port hierarchy. Existing models on the spatial and functional evolution of ports and port systems only partially fit into the new freight distribution paradigm. This paper aims to add to existing literature by introducing a port regionalization phase in port and port system development. It is demonstrated that the regionalization phase and associated hinterland concepts demand new approaches to port governance and a functional focus that goes beyond the traditional port perimeter.

Forest response to elevated CO2 is conserved across a broad range of productivity.

Abstract: Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C uptake by the biosphere increases in response to the fossil-fuel driven increase in atmospheric [CO2] (“CO2 fertilization”), thereby slowing the rate of increase in atmospheric [CO2]. Carbon exchanges between the terrestrial biosphere and atmosphere are often first represented in models as net primary productivity (NPP). However, the contribution of CO2 fertilization to the future global C cycle has been uncertain, especially in forest ecosystems that dominate global NPP, and models that include a feedback between terrestrial biosphere metabolism and atmospheric [CO2] are poorly constrained by experimental evidence. We analyzed the response of NPP to elevated CO2 (≈550 ppm) in four free-air CO2 enrichment experiments in forest stands. We show that the response of forest NPP to elevated [CO2] is highly conserved across a broad range of productivity, with a stimulation at the median of 23 ± 2%. At low leaf area indices, a large portion of the response was attributable to increased light absorption, but as leaf area indices increased, the response to elevated [CO2] was wholly caused by increased light-use efficiency. The surprising consistency of response across diverse sites provides a benchmark to evaluate predictions of ecosystem and global models and allows us now to focus on unresolved questions about carbon partitioning and retention, and spatial variation in NPP response caused by availability of other growth limiting resources.

Compilation of small ribosomal subunit RNA sequences

Abstract: Table 1 lists data on 455 small ribosomal subunit RNA (further abbreviated as srRNA) sequences (references 1 —452) that have been published or submitted to the EMBL or GenBank nucleotide sequence libraries and that are presently stored in aligned form in our data base. The number identifying each sequence in the first column of Table 1 corresponds with the literature reference. If two or more closely related species share the same sequence, they bear the same number, followed by a different lower case character, and the common sequence is listed only once in our alignment. The set of 452 different sequences consists of 97 eukaryotic cytoplasmic, 19 archaebacterial, 276 eubacterial, 16 plastidial, and 44 mitochondrial srRNAs. It comprises all sequences that to our knowledge had been published or were available from the sequence library file servers as of December 1, 1990, and that are either complete or cover a minimum of about 70% of the complete sequence. Partial sequences are included because some of the methods now frequently used for srRNA sequencing preclude the determination of the structure at one or both of the termini. One such method consists of reverse transcription of the srRNA by means of primers complementary to conserved areas in the primary structure (453). In this case the 3'-terminal sequence cannot be found. Another approach (55, 328) involves amplification of the rDNA by means of the polymerase chain reaction (454), using primers binding to conserved areas near the termini, but within the sequence coding for the mature small subunit RNA. In this case both terminal sequences remain unknown. Both methods allow to establish a continuous sequence covering more than 95% of the structure, provided that a sufficient number of primers complementary to internal conserved areas is used. Some authors (e.g. 455), however, use a more limited set of primers and publish sequences that are not only partial but also discontinuous.