1,058 research outputs found

    Pollution and the Efficiency of Urban Growth

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    We analyze the efficiency of urbanization patterns in a dynamic model of endogenous urban growth with two sectors of production. Production exhibits increasing returns to scale on aggregate. Urban environmental pollution, as a force that discourages agglomeration, is caused by domestic production. We show that cities are too large and too few in number in equilibrium, compared to the efficient urbanization path, if economic growth implies increasing aggregate emissions. If, on the other hand, production becomes cleaner over time (`quality growth') the urbanization path approximates the efficient outcome after finite time.Cities, Urbanisation, Pollution, Growth, Migration, Sustainable Development

    Applying Design Thinking Elsewhere: Organizational context matters

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    In this contribution design thinking is taken as a transfer of design methods from product development to other domains. It is argued that the success of this transfer depends on the organisational context offered to design thinking in these other domains. We describe the application of design methods in product development and in two new domains by what we have called the IDER model, where D refers to design and I, E and R to the organisational context. Then we show that characteristics of the contexts in the new domains may determine the success of applying design thinking in these domains. Finally we focus on the transitions among design and the other contextual elements as another source that can ‘make or break’ the success of applying design thinking. We support our arguments with two cases of design thinking: social design and business-innovation design

    Fine-scale spatial genetic structure in the frankincense tree Boswellia papyrifera (Del.) Hochst. and implications for conservation

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    The fine-scale genetic structure and how it varies between generations depends on the spatial scale of gene dispersal and other fundamental aspects of species’ biology, such as the mating system. Such knowledge is crucial for the design of genetic conservation strategies. This is particularly relevant for species that are increasingly fragmented such as Boswellia papyrifera. This species occurs in dry tropical forests from Ethiopia, Eritrea and Sudan and is an important source of frankincense, a highly valued aromatic resin obtained from the bark of the tree. This study assessed the genetic diversity and fine-scale spatial genetic structure (FSGS) of two cohorts (adults and seedlings) from two populations (Guba-Arenja and Kurmuk) in Western Ethiopia and inferred intra-population gene dispersal in the species, using microsatellite markers. The expected heterozygosity (HE) was 0.664–0.724. The spatial analyses based on kinship coefficient (Fij) revealed a significant positive genetic correlation up to a distance of 130 m. Spatial genetic structure was relatively weak (Sp = 0.002–0.014) indicating that gene dispersal is extensive within the populations. Based on the FSGS patterns found, we estimate indirectly gene dispersal distances of 103 and 124 m for the two populations studied. The high heterozygosity, the low fixation index and the low Sp values found in this study are consistent with outcrossing as the (predominant) mating system in B. papyrifera. We suggest that seed collection for ex situ conservation and reforestation programmes of B. papyrifera should use trees separated by distances of at least 100 m but preferably 150 m to limit genetic relatedness among seeds from different trees

    Seven different genes encode a diverse mixture of isoforms of Bet v 1, the major birch pollen allergen

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    BACKGROUND: Pollen of the European white birch (Betula pendula, syn. B. verrucosa) is an important cause of hay fever. The main allergen is Bet v 1, member of the pathogenesis-related class 10 (PR-10) multigene family. To establish the number of PR-10/Bet v 1 genes and the isoform diversity within a single tree, PCR amplification, cloning and sequencing of PR-10 genes was performed on two diploid B. pendula cultivars and one interspecific tetraploid Betula hybrid. Sequences were attributed to putative genes based on sequence identity and intron length. Information on transcription was derived by comparison with homologous cDNA sequences available in GenBank/EMBL/DDJB. PCR-cloning of multigene families is accompanied by a high risk for the occurrence of PCR recombination artifacts. We screened for and excluded these artifacts, and also detected putative artifact sequences among database sequences. RESULTS: Forty-four different PR-10 sequences were recovered from B. pendula and assigned to thirteen putative genes. Sequence homology suggests that three genes were transcribed in somatic tissue and seven genes in pollen. The transcription of three other genes remains unknown. In total, fourteen different Bet v 1-type isoforms were identified in the three cultivars, of which nine isoforms were entirely new. Isoforms with high and low IgE-reactivity are encoded by different genes and one birch pollen grain has the genetic background to produce a mixture of isoforms with varying IgE-reactivity. Allergen diversity is even higher in the interspecific tetraploid hybrid, consistent with the presence of two genomes. CONCLUSION: Isoforms of the major birch allergen Bet v 1 are encoded by multiple genes, and we propose to name them accordingly. The present characterization of the Bet v 1 genes provides a framework for the screening of specific Bet v 1 genes among other B. pendula cultivars or Betula species, and for future breeding for trees with a reduced allergenicity. Investigations towards sensitization and immunotherapy should anticipate that patients are exposed to a mixture of Bet v 1 isoforms of different IgE-reactivity, even if pollen originates from a single birch tree

    Assessment of Physical Fitness After Bariatric Surgery and Its Association with Protein Intake and Type of Cholecalciferol Supplementation

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    Background: Several studies showed that there is a relationship between vitamin and mineral status and muscle strength. In particular this is the case for handgrip strength (HS) and vitamin D deficiency. In bariatric surgery there is a risk of decrease in muscle strength after surgery and also vitamin and mineral deficiencies are not uncommon. The aim of this study is to assess the effect of low vitamin 25 (OH) cholecalciferol levels, high dose cholecalciferol supplementation regime and protein intake on physical fitness, measured using handgrip strength (HS) and the shuttle walk run test (SWRT). Methods: For this retrospective study, 100 patients who have had bariatric surgery were included. Group A (n = 50) used 800 IU oral cholecalciferol per day. Group B (n = 50) used 800 IU oral cholecalciferol daily and 50,000 IU liquid cholecalciferol monthly lifelong. Both groups were matched on common variables. To measure physical fitness, we used the HS manometer of Jamar and the Shuttle Walk Run Test (SWRT) to assess physical capacity. Results: No significant differences in HS and SWRT outcomes were found between patients with serum 25 (OH) cholecalciferol \u3c 75 nmol/L or \u3e75 nmol/L. The postoperative HS is significantly influenced by protein intake (p = 0.017) and no significant influence was seen in outcomes of the SWRT (p = 0.447). Conclusion: We have found that serum 25 (OH) cholecalciferol and different cholecalciferol supplementation regimes do not have a significant effect on HS and SWRT before, three and 6 months after surgery. It seems that protein intake plays a more important role in maintaining adequate muscle strength

    Proteolytic enzyme and inhibitor levels in reindeer (Rangifer tarandus tarandus L.) vs. bovine longissimus muscle, as they relate to ageing rate and response

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    Eight reindeer bulls (age 1.5 years) and six Friesian bulls (age 1.5 years) were included in the study for comparison of tenderness. The reindeer were slaughtered at a commercial reindeer slaughter plant in northern Sweden and the Friesian bulls at a commercial slaughter plant in The Netherlands. Samples for determination of calpain/calpastatin activity were taken from the M. longtssimus (LO) within 1 h post mortem (p.m.), and at various times p.m. pH and temperature were registered in LO; ultimate pH values were measured at 24 h p.m. for beef and at 35 h p.m. for reindeer. At day 1 p.m., samples of LO from both carcass sides were excised, divided in two parts, vacuum packaged and stored at 0-2 °C. One part of each muscle was randomly sampled at 1, 3, 7 and 14 days p.m. for determination of shear force, proteolytic enzyme activity, myofibrillar protein degradation, collagen content and heat solubility. pH and temperature fall was faster in reindeer than in beef. Collagen content in reindeer muscle was found to be low but collagen was 4 times less soluble as compared with beef. Reindeer LO was found to be extremely tender, at 3 days p.m. shear force values were only 2-3 kg/cm2 (8-12 kg/cm2 for beef LO). In reindeer meat, the jJ.-calpain levels dropped to about 55% within 3 days. Troponin T and 30 kDa values were not related to changes in tenderness in reindeer meat. Cathepsin activities in reindeer were up to ten times higher than in beef. As in beef, cathepsin B+L levels in reindeer increased during storage, which is probably associated with a decrease in cystatin-like inhibitor levels
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