A Minimal Congruence Lattice Representation for ₚ₊₁

Let p be an odd prime. The unary algebra consisting of the dihedral group of order 2p, acting on itself by left translation, is a minimal congruence lattice representation of p+1

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223

Lattice residuability

Residuated lattices form the basis of certain kinds of logical interpretations. Also, complete commutative integral zero-bounded residuated lattices are used as a set of truth values for fuzzy logic values, Which are more general than the traditional bounded interval introduced by Zadeh. At times, it is important to know whether or not the lattice can be residuated in the first place. This thesis reviews the literature in lattice residuability and adds more observations. Specifically, (1) bounded chains and top-residuated lattices are show [sic] to be residuable, and (2) additional conditions necessary for residuability are established --Abstract, page iii

USSES - an urban stream stability expert system

Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732An expert system for analyzing urban stream stability and developing mitigation measures for stream instabilities is developed using principles of the geomorphologic, hydraulic, and hydrologic processes that occur in a stream system and their effects on the system upstream and downstream. The hydrologic and hydraulic aspects of the system that affect flow in the stream and often the sediment load that enters the system from beyond the channel boundaries, as well as those aspects that are important to erosion processes are included in the expert system. Finally, available engineering knowledge of sediment transport and its importance to prediction of erosion and stream stability along with mitigation techniques used to restore stability are functionally included in this expert system. The first step is to determine which of the major processes are most important in a particular stream or reach of stream. These processes may include deposition, erosion, bed degradation, and lateral migration of the channel. This requires the stream to be investigated. By observing the stream as it is currently, by obtaining information on the urban development and the hydrologic impact of that development, within the basin (when and where), and determining changes in stream geomorphologic factors such as channel width/depth, channel meandering, effective discharge, or sediment load over time stream stability can be determined. To be able to fully comprehend all of the implications of this information and find an appropriate solution to problems that are discovered, it is necessary to have knowledge of stream geomorphology, urban surface water hydrology, and engineering mitigation techniques. Stream geomorphology is the study of the processes that are causing changes in the physical system and their effects on the system must be understood. The aspects of surface water hydrology important in this instance deal with the processes that affect flow in the stream and the sediment load that enters the system from beyond the channel system. Finally, knowledge of how and when available mitigation techniques can be applied to induce stability in a stream are essential components of the expert system. In order to effectively address the problem it is necessary to look at all aspects of the streams where problems are occurring. While it might alleviate the symptoms to rip-rap or concrete-line a bank area where excessive erosion is occurring, this will not solve the problem, as the sediment capacity of the stream is not changed. Instead, a new area of erosion will occur to supply the stream with its required sediment load. A better approach is one that takes into account the stream processes and addresses the causes of the problems, rather than simply treating the effects. Optimal solutions that are cost-effective and more natural in appearance may be well suited to some of the situations, and the number of occasions when more drastic means of solving sediment control problems need to be instigated can be reduced. By applying geomorphologically sound, engineering approaches to the problems of erosion control in an urban environment, many aspects of the problem can be considered to provide a solution that is beneficial environmentally, hydrologically, and economically. Through the use of sediment models along with hydrologic and hydraulic models, properly engineered solutions can be developed. By determining the required information to perform such an analysis and using efficient methods of collecting the information, an effective plan could easily be implemented by an urban community. The Urban Stream Stability Expert System, USSES may avert many future problems. In residential areas within a city where there are problems, mitigation measures that save property values by protecting property from degradation by using an aesthetically pleasing technology can be extremely valuable. Further, this system’s value increases when actions taken in a specific area also serve to mitigate future, downstream problems. The ability to distinguish future problem areas is also a valuable one. If this type of procedure can be easily applied by a city, then it is possible to reduce problems by applying proper strategies to developing areas as they develop