Scheduling railway traffic at a construction site

We consider the problem of rescheduling trains in the case where one track of a railway section consisting of two tracks in opposing directions is closed due to construction activities. After presenting an appropriate model for this situation we derive a polynomial algorithm for the subproblem of finding an optimal schedule with minimal latenesss if the subsequences of trains for both directions outside the construction site are fixed. Based on this algorithm we propose a local search procedure for the general problem of finding good schedules and report test results for some real world instances. Received: December 8, 1999 / Accepted: May 2, 2001     

Do the Kallikaks look "menacing" or "retarded?"

To extend R. E. Fancher's (see record 1987-31600-001) review of claims that photographs of the Kallikak family in H. H. Goddard's (1912) study had been retouched to make them look more menacing and retarded, 29 Ss (aged 18–69 yrs) were surveyed for their impressions of the photographs. Overall, Ss were strongly inclined to view the photographed individuals as "kind" and "very bright." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

(S)-Reutericyclin: Susceptibility Testing and In Vivo Effect on Murine Fecal Microbiome and Volatile Organic Compounds

We aimed to assess the in vitro antimicrobial activity and the in vivo effect on the murine fecal microbiome and volatile organic compound (VOC) profile of (S)-reutericyclin. The antimicrobial activity of (S)-reutericyclin was tested against Clostridium difficile, Listeria monocytogenes, Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Staphylococcus (S.) epidermidis, Streptococcus agalactiae, Pseudomonas aeruginosa and Propionibacterium acnes. Reutericyclin or water were gavage fed to male BALBc mice for 7 weeks. Thereafter stool samples underwent 16S based microbiome analysis and VOC analysis by gas chromatography mass spectrometry (GC-MS). (S)-reutericyclin inhibited growth of S. epidermidis only. Oral (S)-reutericyclin treatment caused a trend towards reduced alpha diversity. Beta diversity was significantly influenced by reutericyclin. Linear discriminant analysis Effect Size (LEfSe) analysis showed an increase of Streptococcus and Muribaculum as well as a decrease of butyrate producing Ruminoclostridium, Roseburia and Eubacterium in the reutericyclin group. VOC analysis revealed significant increases of pentane and heptane and decreases of 2,3-butanedione and 2-heptanone in reutericyclin animals. The antimicrobial activity of (S)-reutericyclin differs from reports of (R)-reutericyclin with inhibitory effects on a multitude of Gram-positive bacteria reported in the literature. In vivo (S)-reutericyclin treatment led to a microbiome shift towards dysbiosis and distinct alterations of the fecal VOC profile.     

Parallel batch scheduling of equal-length jobs with release and due dates

In this paper we study parallel batch scheduling problems with bounded batch capacity and equal-length jobs in a single and parallel machine environment. It is shown that the feasibility problem 1|p-batch,b<n,r _j ,p _j =p,C _j ≤d _j |− can be solved in O(n ²) time and that the problem of minimizing the maximum lateness can be solved in O(n ²log n) time. For the parallel machine problem P|p-batch,b<n,r _j ,p _j =p,C _j ≤d _j |− an O(n ³log n)-time algorithm is provided, which can also be used to solve the problem of minimizing the maximum lateness in O(n ³log ² n) time.     

Peer-it: Stick-on solutions for networks of things

An integrated, autonomous stick-on computing platform is proposed, consisting of (i) the Peer-it stick-on, multi-sensor, multi-actuator computer hardware, (ii) the Peer-it component-based software framework, and (iii) the Peer-it profile markup language PeerML, supporting spontaneous interaction among such platforms. The platform implements Peer-to-Peer computing principles in a self-contained, miniaturized, universal and scalable way, giving raise for application scenarios where the real-world artefacts like e.g. machines, tools or appliances–literally every thing–equipped with Peer-it technology can operate in spontaneously interacting, goal-oriented ensembles.Technically, preferences (like capabilities and goals) and context (like time, geo-position, owner, environmental conditions, etc.) of peers are kept as a profile encoded in PeerML in the local memory of Peer-its, and carried along wherever they move in space. Once peers come into spatial proximity of each other, profiles are exchanged via wireless communication, and the “similarity” of preferences is analyzed. In the case of “matching” preferences, an associated application is notified on both peers.Besides a fully functional autonomous hardware platform integrating multiple sensors, actuator arrays and wireless communication technologies, the Peer-it stick-on computer, a low-memory footprint, OSGi compliant Peer-it software framework has been implemented. We demonstrate in a flexible manufacturing systems (FMS) scenario, how the Peer-it technology can improve over centralized FMSs with respect to fault tolerance, scalability, flexibility in reconfiguration, productivity and efficiency.     

Securing Passive Objects in Mobile Ad-Hoc Peer-to-Peer Networks

Security and privacy in mobile ad-hoc peer-to-peer environments are hard to attain, especially when working with passive objects (without own processing power, e.g. RFID tags). This paper introduces a method for integrating such objects into a peer-to-peer environment without infrastructure components while providing a high level of privacy and security for peers interacting with objects. The integration is done by associating public keys to passive objects, which can be used by peers to validate proxies (peers additionally acting on behalf of objects). To overcome the problem of limited storage capacity on small embedded objects, ECC keys are used.     

Characterization of tribo-layers on self-lubricating plasma-assisted chemical-vapor-deposited TiN coatings

Recently, several new solid lubricants and modern lubrication concepts have been developed to achieve lower friction and wear and thus longer lifetime in severe tribological applications. The aim of this study is to characterize tribo-layers formed during ball-on-disc testing on low-friction, Cl-containing TiN coatings deposited by plasma assisted chemical vapor deposition and to clarify their formation mechanism. Characterization of the transfer layers was done by optical microscopy, optical profilometry, Raman spectroscopy, Auger electron spectroscopy and X-ray photoelectron spectroscopy. Differential scanning calorimetry was used to provide information on the chlorine-influenced chemical reactions of the coatings in ambient air. Iron oxide layers of a thickness in the nm-range have been found on low-chlorine containing TiN coatings (<3 at.% Cl) showing friction coefficients of approximately 0.8, whereas on TiN coatings with higher chlorine contents (>3 at.% Cl) rutile layers were preferably formed, resulting in friction coefficients below 0.2. This self-lubrication mechanism can be explained by the in-situ formation of easy-shearable titanium oxides in the contact zone in the presence of humidity and oxygen.     

Salmonella biofilms: An overview on occurrence,structure, regulation and eradication

The ability of Salmonella to form complex surface-associated communities, called biofilms, contributes to its resistance and persistence in both host and non-host environments and is especially important in food processing environments. In this review, the different types of abiotic (plastic, glass, cement, rubber, and stainless steel) and biotic surfaces (plant surfaces, epithelial cells, and gallstones) on which Salmonella biofilms have been described are discussed, as well as a number of commonly used laboratory setups to study Salmonella biofilm formation (rdar morphotype, pellicle formation, and biofilms on polystyrene pegs). Furthermore, the structural components important during Salmonella biofilm formation are described (curli and other fimbriae, BapA, flagella, cellulose, colanic acid, anionic O-antigen capsule and fatty acids), with special attention to the structural variations of biofilms grown on different surfaces and under different conditions. Indeed, biofilm formation is strongly influenced by different environmental signals, via a complex regulatory network. An extensive overview is given on the current understanding of this genetic network and the interactions between its different components (CsgD, RpoS, Crl, OmpR, IHF, H-NS, CpxR, MlrA, c-di-GMP, BarA/SirA, Csr, PhoPQ, RstA, Rcs, metabolic processes and quorum sensing). To further illustrate that biofilm formation is a mechanism of Salmonella to adapt to different environments, the resistance of Salmonella biofilms against different stress factors including desiccation stress, disinfectants (e.g. hypochlorite, glutaraldehyde, cationic tensides and triclosan) and antibiotics (e.g. ciprofloxacin) is described. Finally, a number of Salmonella biofilm inhibitors, identified through bottom-up- and top-down-approaches, are discussed, such as surfactin, glucose, halogenated furanones, 4(5)-aryl 2-aminoimidazoles, furocoumarins and salicylates. Also the potential of combination therapy (e.g. combinations of triclosan and quaternary ammonium salts or halogenated furanones and antibiotics/disinfectants) and nano- and micro-emulsions to inhibit Salmonella biofilm formation is discussed. Insight into the pathogen's complex biofilm process will eventually lead to further unraveling of its intricacies and more efficient strategies to combat Salmonella biofilms.