3,134 research outputs found
Practical Schemes For Privacy & Security Enhanced RFID
Proper privacy protection in RFID systems is important. However, many of the
schemes known are impractical, either because they use hash functions instead
of the more hardware efficient symmetric encryption schemes as a efficient
cryptographic primitive, or because they incur a rather costly key search time
penalty at the reader. Moreover, they do not allow for dynamic, fine-grained
access control to the tag that cater for more complex usage scenarios.
In this paper we investigate such scenarios, and propose a model and
corresponding privacy friendly protocols for efficient and fine-grained
management of access permissions to tags. In particular we propose an efficient
mutual authentication protocol between a tag and a reader that achieves a
reasonable level of privacy, using only symmetric key cryptography on the tag,
while not requiring a costly key-search algorithm at the reader side. Moreover,
our protocol is able to recover from stolen readers.Comment: 18 page
An Outlook on the Localisation and Structure-Function Relationships of R Proteins in Solanum
The co-evolution of plants and plant-pathogens shaped a multi-layered defence system in plants, in which Resistance proteins (R proteins) play a significant role. A fundamental understanding of the functioning of these R proteins and their position in the broader defence system of the plant is essential. Sub-project 3 of the BIOEXPLOIT programme studies how R proteins are activated upon effector recognition and how recognition is conveyed in resistance signalling pathways, using the solanaceous R proteins Rx1 (from S. tuberosum spp. andigena; conferring extreme resistance against Potato Virus X), I-2 (from S. lycopersicon; mediating resistance to Fusarium oxysporum) and Mi-1.2 (from S. lycopersicon; conferring resistance to Meloidogyne incognita) as model systems. The results obtained in this project will serve as a model for other R proteins and will be translated to potential applications or alternative strategies for disease resistance. These include the modification of the recognition specificity of R proteins with the aim to obtain broad spectrum resistance to major pathogens in potato
A comparison of TCAR, CIR and LAMBDA GNSS ambiguity resolution
With the envisioned introduction of three-carrier GNSS's (modernized GPS, Galileo), new methods of ambiguity resolution have been developed. In this contribution we will compare two important candidate methods for triple-frequency ambiguity resolution with the already existing LAMBDA (Least-squares Ambiguity Decorrelation Adjustment) method; the TCAR (Three-Carrier Ambiguity Resolution) method; and the CIR (Cascading Integer Resolution) method. It will be shown that for their estimation principle, both TCAR and CIR rely on integer bootstrapping, whereas LAMBDA is based on integer least-squares, of which optimality has been proven, that is, highest probability of success. In TCAR and CIR pre-defined ambiguity transformation are used, whereas LAMBDA exploits the information content of the full ambiguity variance-covariance matrix, with statistical decorrelation the objective in constructing the ambiguity transformation. For the aspect of resolving the ambiguities, TCAR and CIR are designed for use with the geometry-free model. LAMBDA can intrinsically handle any GNSS model with integer ambiguities and thereby utilize satellite geometry to its benefit in geometry-based models
Re-refinement from deposited X-ray data can deliver improved models for most PDB entries
An evaluation of validation and real-space intervention possibilities for improving existing automated (re-)refinement methods
Association between nutritional status and subjective health status in chronically ill children attending special schools
Purpose: In hospitalized children with a chronic disease, malnutrition was associated with a lower subjective health status. In outpatient children with a chronic disease attending special schools, this association has never been studied. The aim of this study was to assess the association between nutritional status and subjective health status in chronically ill children attending special schools. Methods: Overall, 642 children, median age 9.8 years (IQR 7.7–11.5), 60 % male, 72 % Caucasian, were included in this prospective study in nine special schools for chronically ill children in the Netherlands. Overall malnutrition was assessed as: acute malnutrition (<−2 SDS for weight for height (WFH)) and chronic malnutrition (<−2 SDS for height for age). The malnutrition risk was assessed with the nutritional risk-screening tool STRONGkids. Subjective health status was assessed with EQ-5D. Results: Overall, 16 % of the children had overall malnutrition: 3 % acute and 13 % chronic malnutrition. Nurses reported ‘some/severe problems’ on the health status dimensions mobility (15 %), self-care (17 %), usual activities (19 %), pain/discomfort (22 %), and anxiety/depression (22 %) in chronically ill children. Their mean visual analogue scale score (VAS) was 73.0 (SD 11.1). Malnutrition, medication usage, and younger age explained 38 % of the variance of the VAS score. Conclusions: The presence of overall malnutrition in chronically ill children attending special schools was associated with lower subjective health status, especially in younger children and in those with chronic medication usage. Therefore, it is important to develop and use profile-screening tools to identify these children
Radiofrequency ablation is beneficial in simultaneous treatment of synchronous liver metastases and primary colorectal cancer
In patients with resectable synchronous colorectal liver metastases (CRLM), either two-staged or simultaneous resections of the primary tumor and liver metastases are performed. Data on radiofrequency ablation (RFA) for the treatment of CRLM during a simultaneous procedure is lacking. The primary aim was to analyze short-term and long-term outcome of RFA in simultaneous treatment. A secondary aim was to compare simultaneous resection with the colorectal-first approach.Retrospective analysis of 241 patients with colorectal cancer and synchronous CRLM between 2000-2016. Median follow-up was 36.1 months (IQR 18.2-58.8 months). A multivariable analysis was performed to analyze the postoperative morbidity, using the comprehensive complication index. A propensity matched analysis was performed to compare survival rates.In multivariable analysis, the best predictor of lower complication severity was treatment with RFA (p = 0.040). Higher complication rates were encountered in patients who underwent an abdominoperineal resection (p = 0.027) or age > 60 years (p = 0.022). The matched analysis showed comparable overall survival in RFA treated patients versus patients undergoing a liver resection with a five year overall survival of 39.4% and 37.5%, respectively (p = 0.782). In a second matched analysis, 5-year overall survival rates in simultaneously treated patients (43.8%) was comparable to patients undergoing the colorectal first approach (43.0%, p = 0.223).RFA treatment of CRLM in simultaneous procedures is associated with a lower complication severity and non-inferior oncological outcome as compared to partial liver resection. RFA should be considered a useful alternative to liver resection
Automatic rebuilding and optimization of crystallographic structures in the Protein Data Bank
Motivation: Macromolecular crystal structures in the Protein Data Bank (PDB) are a key source of structural insight into biological processes. These structures, some >30 years old, were constructed with methods of their era. With PDB_REDO, we aim to automatically optimize these structures to better fit their corresponding experimental data, passing the benefits of new methods in crystallography on to a wide base of non-crystallographer structure users
Hydrological landscape settings of base-rich fen mires and fen meadows:an overview
Question: Why do similar fen meadow communities occur in different landscapes? How does the hydrological system sustain base-rich fen mires and fen meadows? Location: Interdunal wetlands and heathland pools in The Netherlands, percolation mires in Germany, Poland, and Siberia, and calcareous spring fens in the High Tatra, Slovakia. Methods: This review presents an overview of the hydrological conditions of fen mires and fen meadows that are highly valued in nature conservation due to their high biodiversity and the occurrence of many Red List species. Fen types covered in this review include: (1) small hydrological systems in young calcareous dune areas, and (2) small hydrological systems in decalcified old cover sand areas in The Netherlands; (3) large hydrological systems in river valleys in Central-Europe and western-Siberia, and (4) large hydrological systems of small calcareous spring fens with active precipitation of travertine in mountain areas of Slovakia. Results: Different landscape types can sustain similar nutrient poor and base-rich habitats required by endangered fen meadow species. The hydrological systems of these landscapes are very different in size, but their groundwater flow pattern is remarkably similar. Paleo-ecological research showed that travertine forming fen vegetation types persisted in German lowland percolation mires from 6000 to 3000 BP. Similar vegetation types can still be found in small mountain mires in the Slovak Republic. Small pools in such mires form a cascade of surface water bodies that stimulate travertine formation in various ways. Travertine deposition prevents acidification of the mire and sustains populations of basiphilous species that elsewhere in Europe are highly endangered. Conclusion: Very different hydrological landscape settings can maintain a regular flow of groundwater through the top soil generating similar base-rich site conditions. This is why some fen species occur in very different landscape types, ranging from mineral interdunal wetlands to mountain mires
PDB_REDO: constructive validation, more than just looking for errors
The decision-making algorithms and software used in PDB_REDO to re-refine and rebuild crystallographic protein structures in the PDB are presented and discussed
A Case of Intrathoracic Stomach and Spleen After Aortic Repair: An Unusual Complication
A patient is described who presented with an intrathoracic stomach and spleen two weeks after aortic repair for an aortoduodenal fistula. At an urgent laparotomy the stomach was repositioned and the spleen removed. The patient recovered fully. The possible mechanism of this severe complication is discussed and relevant literature reviewed
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