323 research outputs found
Cost Drivers of Operation Charges and Variation over Time: An Analysis Based on Semiparametric SUR Models
Although building operating charges have turned out to be a major determinant of profitability for real estate investments, there is a noticeable lack of reports or studies that analyze these costs with state-of-the-art statistical techniques. Specifically, past studies usually assume linear relationships between costs and building attributes, they do not control for cluster-specific or longitudinal effects and do not account for the simultaneous structure of cost categories. Therefore, in this study we provide a novel approach to real estate cost benchmarking: We analyze the effects of building attributes on electricity, heating and maintenance costs for office buildings in Germany in a multivariate structured additive regression (STAR) model simultaneously, modeling potentially nonlinear effects as P(enalized)-Splines and controlling for cluster-specific and individual heterogeneity in a three-way random effects structure. This way, we gain insights into how building attributes influence costs, and how cost levels vary across cities, companies and buildings. We furthermore derive quality-adjusted time indices for the two major German submarkets, the former German Democratic Republic and the old West German states. The results obtained can be used to derive portfolio allocation strategies and for planning, constructing, operating and redeveloping real estate
Avalanche related damage potential - changes of persons and mobile values since the mid-twentieth century, case study Galtür
When determining risk related to natural hazard processes, many studies neglect the investigations of the damage potential or are limited to the assessment of immobile values like buildings. However, persons as well as mobile values form an essential part of the damage potential. Knowledge of the maximum number of exposed persons in an endangered area is of great importance for elaborating evacuation plans and immediate measures in case of catastrophes. In addition, motor vehicles can also be highly damaged, as was shown by the analysis of avalanche events. With the removal of mobile values in time as a preventive measure this kind of damage can be minimised. <P style='line-height: 20px;'> This study presents a method for recording the maximum number of exposed persons and monetarily assessing motor vehicles in the municipality of Galtür (Tyrol, Austria). Moreover, general developments of the damage potential due to significant socio-economic changes since the mid-twentieth century are pointed out in the study area. The present situation of the maximum number of persons and mobile values in the official avalanche hazard zones of the municipality is described in detail. Information on the number of persons is derived of census data, tourism and employment statistics. During the winter months, a significant increase overlaid by strong short-term fluctuation in the number of persons can be noted. These changes result from a higher demand of tourism related manpower as well as from varying occupancy rates. The number of motor vehicles in endangered areas is closely associated to the number of exposed persons. The potential number of motor vehicles is investigated by means of mapping, statistics on the stock of motor vehicles and the density distribution. Diurnal and seasonal fluctuations of the investigated damage potential are pointed out. The recording of the number of persons and mobile values in endangered areas is vital for any disaster management
Modelling the system behaviour of wet snow avalanches using an expert system approach for risk management on high alpine traffic roads
The presented approach describes a model for a rule-based expert system calculating the temporal variability of the release of wet snow avalanches, using the assumption of avalanche triggering without the loading of new snow. The knowledge base of the model is created by using investigations on the system behaviour of wet snow avalanches in the Italian Ortles Alps, and is represented by a fuzzy logic rule-base. Input parameters of the expert system are numerical and linguistic variables, measurable meteorological and topographical factors and observable characteristics of the snow cover. Output of the inference method is the quantified release disposition for wet snow avalanches. Combining topographical parameters and the spatial interpolation of the calculated release disposition a hazard index map is dynamically generated. Furthermore, the spatial and temporal variability of damage potential on roads exposed to wet snow avalanches can be quantified, expressed by the number of persons at risk. The application of the rule base to the available data in the study area generated plausible results. The study demonstrates the potential for the application of expert systems and fuzzy logic in the field of natural hazard monitoring and risk management
A comparison of building value models for flood risk analysis
Quantitative flood risk analyses support decisions in
flood management policies that aim for cost efficiency. Risk is commonly
calculated by a combination of the three quantified factors: hazard,
exposure and vulnerability. Our paper focuses on the quantification of
exposure, in particular on the relevance of building value estimation
schemes within flood exposure analyses on regional to national scales. We
compare five different models that estimate the values of flood-exposed
buildings. Four of them refer to individual buildings, whereas one is based
on values per surface area, differentiated by land use category. That one
follows an approach commonly used in flood risk analyses on regional or
larger scales. Apart from the underlying concepts, the five models differ in
complexity, data and computational expenses required for parameter
estimations and in the data they require for model application.The model parameters are estimated by using a database of more than half a
million building insurance contracts in Switzerland, which are provided by
11 (out of 19) cantonal insurance companies for buildings that operate under
a monopoly within the respective Swiss cantons. Comparing the five model
results with the directly applied spatially referenced insurance data
suggests that models based on individual buildings produce better results
than the model based on surface area, but only if they include an individual
building's volume.Applying the five models to all of Switzerland produces results that are
very similar with regard to the spatial distribution of exposed-building
values. Therefore, for spatial prioritizations, simpler models are
preferable. In absolute values, however, the five model results differ
remarkably. The two simplest models underestimate the overall exposure, and
even more so the extreme high values, upon which risk management strategies
generally focus. In decision-making processes based on cost-efficiency, this
underestimation would result in suboptimal resource allocation for
protection measures. Consequently, we propose that estimating exposed-building values should be based on individual buildings rather than on areas
of land use types. In addition, a building's individual volume has to be
taken into account in order to provide a reliable basis for cost–benefit
analyses. The consideration of other building features further improves the
value estimation. However, within the context of flood risk management, the
optimal value estimation model depends on the specific questions to be
answered. The concepts of the presented building value models are generic.
Thus, these models are transferable, with minimal adjustments according to
the application's purpose and the data available. Within risk analyses, the
paper's focus is on exposure. However, the findings also have direct
implications for flood risk analyses as most risk analyses take the value of
exposed assets into account in a linear way.</p
Trans-Translation in Helicobacter pylori: Essentiality of Ribosome Rescue and Requirement of Protein Tagging for Stress Resistance and Competence
BACKGROUND: The ubiquitous bacterial trans-translation is one of the most studied quality control mechanisms. Trans-translation requires two specific factors, a small RNA SsrA (tmRNA) and a protein co-factor SmpB, to promote the release of ribosomes stalled on defective mRNAs and to add a specific tag sequence to aberrant polypeptides to direct them to degradation pathways. Helicobacter pylori is a pathogen persistently colonizing a hostile niche, the stomach of humans. PRINCIPAL FINDINGS: We investigated the role of trans-translation in this bacterium well fitted to resist stressful conditions and found that both smpB and ssrA were essential genes. Five mutant versions of ssrA were generated in H. pylori in order to investigate the function of trans-translation in this organism. Mutation of the resume codon that allows the switch of template of the ribosome required for its release was essential in vivo, however a mutant in which this codon was followed by stop codons interrupting the tag sequence was viable. Therefore one round of translation is sufficient to promote the rescue of stalled ribosomes. A mutant expressing a truncated SsrA tag was viable in H. pylori, but affected in competence and tolerance to both oxidative and antibiotic stresses. This demonstrates that control of protein degradation through trans-translation is by itself central in the management of stress conditions and of competence and supports a regulatory role of trans-translation-dependent protein tagging. In addition, the expression of smpB and ssrA was found to be induced upon acid exposure of H. pylori. CONCLUSIONS: We conclude to a central role of trans-translation in H. pylori both for ribosome rescue possibly due to more severe stalling and for protein degradation to recover from stress conditions frequently encountered in the gastric environment. Finally, the essential trans-translation machinery of H. pylori is an excellent specific target for the development of novel antibiotics
The PDZ domain of the SpoIVB serine peptidase facilitates multiple functions
During spore formation in Bacillus subtilis, the SpoIVB protein is a critical component of the sigma (K) regulatory checkpoint. SpoIVB has been shown to be a serine peptidase that is synthesized in the spore chamber and which self-cleaves, releasing active forms. These forms can signal proteolytic processing of the transcription factor sigma (K) in the outer mother cell chamber of the sporulating cell. This forms the basis of the sigma (K) checkpoint and ensures accurate sigma (K)-controlled gene expression. SpoIVB has also been shown to activate a second distinct process, termed the second function, which is essential for the formation of heat-resistant spores. In addition to the serine peptidase domain, SpoIVB contains a PDZ domain. We have altered a number of conserved residues in the PDZ domain by site-directed mutagenesis and assayed the sporulation phenotype and signaling properties of mutant SpoIVB proteins. Our work has revealed that the SpoIVB PDZ domain could be used for up to four distinct processes, (i) targeting of itself for trans proteolysis, (11) binding to the protease inhibitor BofC, (iii) signaling of pro-sigma (K) processing, and (iv) signaling of the second function of SpoIVB
Joint Endeavor Toward Sustainable Mountain Development: Research at the Institute for Interdisciplinary Mountain Research of the Austrian Academy of Sciences
The sustainable development of mountain regions requires inter-and transdisciplinary knowledge. The Institute for Interdisciplinary Mountain Research contributes to this global endeavor as part of the Austrian Academy of Sciences and as a member of international scientific networks, together with local partners and stakeholders. As a joint effort of individual researchers covering multiple fields, this article highlights our views on mountains as research objects, the phenomena we investigate as parts of entire mountain systems, and the synergies and differences of the disciplinary frames within which we work
Screen for Localized Proteins in Caulobacter crescentus
Precise localization of individual proteins is required for processes such as motility, chemotaxis, cell-cycle progression, and cell division in bacteria, but the number of proteins that are localized in bacterial species is not known. A screen based on transposon mutagenesis and fluorescence activated cell sorting was devised to identify large numbers of localized proteins, and employed in Caulobacter crescentus. From a sample of the clones isolated in the screen, eleven proteins with no previously characterized localization in C. crescentus were identified, including six hypothetical proteins. The localized hypothetical proteins included one protein that was localized in a helix-like structure, and two proteins for which the localization changed as a function of the cell cycle, suggesting that complex three-dimensional patterns and cell cycle-dependent localization are likely to be common in bacteria. Other mutants produced localized fusion proteins even though the transposon has inserted near the 5′ end of a gene, demonstrating that short peptides can contain sufficient information to localize bacterial proteins. The screen described here could be used in most bacterial species
Nascentome Analysis Uncovers Futile Protein Synthesis in Escherichia coli
Although co-translational biological processes attract much attention, no general and easy method has been available to detect cellular nascent polypeptide chains, which we propose to call collectively a “nascentome.” We developed a method to selectively detect polypeptide portions of cellular polypeptidyl-tRNAs and used it to study the generality of the quality control reactions that rescue dead-end translation complexes. To detect nascent polypeptides, having their growing ends covalently attached to a tRNA, cellular extracts are separated by SDS-PAGE in two dimensions, first with the peptidyl-tRNA ester bonds preserved and subsequently after their in-gel cleavage. Pulse-labeled nascent polypeptides of Escherichia coli form a characteristic line below the main diagonal line, because each of them had contained a tRNA of nearly uniform size in the first-dimension electrophoresis but not in the second-dimension. The detection of nascent polypeptides, separately from any translation-completed polypeptides or degradation products thereof, allows us to follow their fates to gain deeper insights into protein biogenesis and quality control pathways. It was revealed that polypeptidyl-tRNAs were significantly stabilized in E. coli upon dysfunction of the tmRNA-ArfA ribosome-rescuing system, whose function had only been studied previously using model constructs. Our results suggest that E. coli cells are intrinsically producing aberrant translation products, which are normally eliminated by the ribosome-rescuing mechanisms
A functional peptidyl-tRNA hydrolase, ICT1, has been recruited into the human mitochondrial ribosome
Bioinformatic analysis classifies the human protein encoded by immature colon carcinoma transcript-1 (ICT1) as one of a family of four putative mitochondrial translation release factors. However, this has not been supported by any experimental evidence. As only a single member of this family, mtRF1a, is required to terminate the synthesis of all 13 mitochondrially encoded polypeptides, the true physiological function of ICT1 was unclear. Here, we report that ICT1 is an essential mitochondrial protein, but unlike the other family members that are matrix-soluble, ICT1 has become an integral component of the human mitoribosome. Release-factor assays show that although ICT1 has retained its ribosome-dependent PTH activity, this is codon-independent; consistent with its loss of both domains that promote codon recognition in class-I release factors. Mutation of the GGQ domain common to ribosome-dependent PTHs causes a loss of activity in vitro and, crucially, a loss of cell viability, in vivo. We suggest that ICT1 may be essential for hydrolysis of prematurely terminated peptidyl-tRNA moieties in stalled mitoribosomes
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