The meaning of tenure under different conditions; empirical evidence from the Netherlands

This paper elaborates upon the meaning of tenure. The discussion is based on the writings of Saunders. His two main conclusions are that homeowners experience a greater sense of freedom and more security than renters, and that homeowners are more closely attached to their neighborhood. These inferences have been questioned on the grounds that major differences exist within the owner-occupier sector. Therefore Saunders' conclusions would not pertain to all homeowners. Moreover, the effects of homeownership and the experiences of homeowners may vary from country to country. This paperpresents an analysis of how homeowners in the Netherlands evaluate their housing situation. The findings are compared with the situation in England. Some of Saunders' insights are substantiated by the results of the analysis, but other conclusions are not confirmed.     

Analysing singularities of a benchmark problem

The purpose of this paper is to analyze the singularities of a well known benchmark problem “Andrews’ squeezing mechanism.” We show that for physically relevant parameter values this system admits singularities, and describe explicit conditions for the parameters. The method is based on Gröbner bases computations and ideal decomposition. It is algorithmic and can thus be applied to study constraint singularities which arise in more general situations as well.     

Relative cost of owner-occupation and renting: A study of six Dutch neighborhoods

Who pays less for housing: the homeowner or the renter? It is widely accepted that the answer is related to the period in time and the income of the households involved. This contribution is concerned with the added effect of place (neighborhood). We calculated the user cost over the period 1978 to 1993 for six different neighborhoods with a stock similar of owner-occupied and rented dwellings. Six neighborhoods in Randstad Holland were selected, each representing a given building period. The data were derived from a questionnaire held in 1993 among renters and homeowners in these neighborhoods. National figures elucidate the differences between income groups and over time. Our data show that the influence of place is not negligible. The housing costs of homeowners and renters alike differ from one neighborhood to another. The influence of place may be attributed to several factors: the building period and the subsidy rules in force at that time; the development of the value of the owner-occupied dwellings; the rent policy; and the land policy.     

Structural features of a polypeptide carrier promoting secretion of a β-lactamase fusion protein in yeast

Escherichia coli β-lactamase was secreted into the culture medium of Saccharomyces cerevisiae in biologically active form, when fused to the C-terminus of the hsp150δ-carrier. The hsp150δ-carrier is an N-terminal fragment of the yeast hsp150 protein, having a signal peptide and consisting mostly of a 19 amino acid peptide repeated 11 times in tandem. Here we expressed the hsp150δ-carrier fragment alone in S. cerevisiae. Apparently due to a positional effect of the gene insertion, large amounts of the hsp150δ-carrier were synthesized. About half of the de novo synthesized carrier molecules were secreted into the culture medium, the rest remaining mostly in the pre-Golgi compartment. The extensively O-glycosylated carrier fragment was purified from the culture medium under non-denaturing conditions. Circular dichroism spectroscopy showed that it had no regular secondary structure. Nuclear magnetic resonance spectroscopy showed that a non-glycosylated synthetic peptide, the consensus sequence of the repetitive 19 amino acid peptide, also lacked secondary structure. The unstructured carrier polypeptide may facilitate proper folding and secretion of heterologous proteins attached to it.     

Vergleichende papierchromatographische Identifizierung der Weine

Zusammenfassung Es ist eine Vorbehandlungs- und chromatographische Analysenmethode für die vergleichende Identifizierung der Weine entwickelt worden, welche sich auf die Bestimmung der Aminosäurezusammensetzung der Weine stützt. Mit dieser Methode kann man den Veränderungen der Aminosäurezusammensetzung auch während der Gärung und der Reifung der Weine folgen.Die Aminosäurechromatogramme desselben Weines sind leicht zu reproduzieren.Die Chromatogramme desselben Weines, aber verschiedenen Jahrganges, weichen voneinander bezüglich der Gesamtkonzentration der Aminosäuren ab. Die Chromatogramme zeigen sich deutlich als von demselben Typus, weil die Verhältnisse unter den Aminosäuren dieselben blieben.Die Chromatogramme der verschiedenen Weinsorten zeigen deutliche Unterschiede besonders im Gesamtaminosäuregehalt. Die Verhältnisse der Mengen von Alanin, Prolin, -Aminobuttersäure, Valin, Leucin undIsoleucin und die Gegenwart oder das Fehlen des Phenylalanins bilden eine gute Bewertungsgrundlage.     

3-D自由立体显示的性能表征

三维自由立体显示的图像生成和参数显示与一般的二维显示不同,需要其它的方法来校验光学性能。目前工业上缺少标准化的三维显示测试方法,报道过的测量结果可能不具有可比性,因此需要建立标准化的测试方法,而且这个方法的计量和度量必须适用于任何一种特定的立体显示技术。文中探索了对自由立体显示技术进行表征的一些方法。     

Testing endocrine disruption in biota samples: a method to remove interfering lipids and natural hormones

A cleanup method was developed to remove coextracted lipids and natural hormones from biota samples in order to test the endocrine-disrupting (ED) capacity of their extracts in in vitro bioassays. Unspiked and spiked fish tissues were cleaned with a combination of dialysis, gel permeation chromatography (GPC), and normal-phase liquid chromatography (NP-HPLC). The spiking mixture consisted of a broad range of environmental pollutants (endocrine disruptors and genotoxic compounds). Chemical recoveries of each test compound, and thyroid-hormone-like and (anti)androgenic activities of the cleaned extracts were investigated. Despite the chemical and toxicological complexity of the spiking mixture and the sequential sample treatment, chemical analysis revealed acceptable recoveries on average: 89 ± 8% after each cleanup step separately and 75 ± 3% after the whole extraction and cleanup procedure in the extracts. In addition, recovered activities in the bioassays were in good agreement with the spiking levels. The developed cleanup method proved to be capable of lipid and natural hormone removal from fish extracts, enabling the measurement of selected endocrine-hormone-like activities in T(4)*-TTR and AR-CALUX bioassays. The method can be used as a sample preparation method of biota samples for toxicity profiling and effect-directed analysis (EDA).     

The Government Mortgage Guarantee as an Instrument in Housing Policy: Self-supporting Instrument or Subsidy?

This paper discusses the role of government mortgage guarantee schemes in housing policy. It explores different types of government mortgage guarantee scheme, which play different roles, in eight countries. Mortgage guarantee schemes interfere in the mortgage market in order to improve access to mortgages. Such guarantees can be shaped as self-supporting instruments or as subsidies. If the latter is the case the issue of competition and a level playing field is relevant. This paper explores the US and the Dutch guarantee models in depth in order to answer the question of whether these schemes are unsubsidised mortgage market instruments or subsidised programmes. It concludes by reflecting on the meaning of the outcomes in the context of EU competition policy.     

Neutral electrolyzed water (NEW), chlorine dioxide,organic acid based product,and ultraviolet‐C for inactivation of microbes in fresh‐cut vegetable washing waters

The effect of decontamination methods on fresh‐cut vegetable washing waters was evaluated. NEW, ClO₂, organic acid‐based product FPW, and UV‐C were tested with and without an interfering carrot juice of 1% (IS), on Yersinia enterocolitica and Yersinia pseudotuberculosis, Escherichia coli, and yeast Candida lambica. The use of ClO₂ (50 ppm active chlorine) resulted in >4 log reduction of Y. enterocolitica, Y. pseudotuberculosis, E. coli and >3 log reduction of C. lambica. The antibacterial effect of NEW was less effective in the presence of IS when compared with ClO_2. The inactivation of C. lambica by FPW reached a maximum of 2.8 log cfu/mL (concentration 0.125%), but the antimicrobial effect was delayed by the IS. The effect of FPW on E. coli was significantly reduced by 1% IS. The inactivation of E. coli and C. lambica with UV‐C IS decreased the inactivation and lengthened its time. Filtration improved the effect of UV‐C inactivation.

Practical applications

When chemical decontamination methods were used in fresh‐cut vegetable processing, the presence of organic matter in process water increased the reaction times and the need for higher concentrations of the chemical decontamination and the time of physical decontamination. Yersinia required longer inactivation times than E. coli. When UV‐C is used for decontamination of process waters, waters should be filtered to enhance the disinfection efficacy.     

Preparation of water‐soluble starch oligomers from variable starch species in 1‐allyl‐3‐methylimidazolium chloride

Native wheat, barley, rice, maize, wx maize, and potato starch species were modified by depolymerization in 1‐allyl‐3‐methylimidazolium chloride ([AMIM]Cl) ionic liquid (IL) using oil bath or microwave heating. Reactions were catalyzed with p‐toluenesulfonic acid (p‐TsOH). Reaction times varied depending on the starch species and its concentration, the heating method, and volume of the reaction mixture. Depolymerization products were analyzed with HPLC‐ELSD. All starch species mostly degraded into water‐soluble 1500–2000 Da‐sized starch oligomers. Glucose and other short‐chained sugars did not precipitate along with starch oligomers due to their high solubility in IL. This property was utilized in the purification of commercial maltodextrins. Produced water‐soluble, low MW starch oligomers might be used, e.g., in bacterial cultivations as a glucose source.