Affine configurations and pure braids

We show that the fundamental group of the space of ordered affine-equivalent configurations of at least five points in the real plane is isomorphic to the pure braid group modulo its centre. In the case of four points this fundamental group is free with eleven generators.Comment: 5 pages, 1 figure, final version; to appear in Discrete & Computational Geometry, available from the publishers at http://www.springerlink.com/content/384516n7q24811ph

The volume flux group and nonpositive curvature

We show that every closed nonpositively curved manifold with non-trivial volume flux group has zero minimal volume, and admits a finite covering with circle actions whose orbits are homologically essential. This proves a conjecture of Kedra-Kotschick-Morita for this class of manifolds.Comment: 6 pages, final version, to appear in Ann. Global Analysis and Geometr

Comparative analysis of the compressive strength of concrete under different curing methods

Concrete is the most widely used material in construction, which possesses different characteristics and possible manufacturing methods. Concrete is, also, characterized by its high resistance to compression and durability, factors that could have been directly influenced by the curing method in early ages. The objective of this research is to demonstrate the importance of the concrete curing process, as well as to analyze the influence of the chosen curing method on the compression resistance. 48 concrete test samples were manufactured, by the standard requirements. Subsequently, the samples were divided into eight batches, subjected to different types of curing: immersion curing, twice a day; outdoor curing; total immersion curing in different waters, application of commercial curing agent; with polyethylene foil coating and without curing. Performing compression testing at 7 and 28 days. Among the results obtained, the batch that underwent the method of curing with polyethylene coating presented a more efficient effect in terms of resistance to compression; followed by the techniques of immersion in water

A profile of deaths among trauma patients in a university hospital: The Philippine experience

BACKGROUND: The Philippine General Hospital (PGH) is the pioneer in trauma care in the country, being the first to create a dedicated Trauma Service in 1989. The service has not conducted a review of its admissions and mortalities since 1992. The purpose of this study is to describe the mortality patterns of this service. METHODS: A descriptive and retrospective 3-year review, covering January 2004 June 2007, was conducted using an electronic patient database. Review of patient records included: population demographics, mechanism of injury, length of stay prior to death, and the cause of death. RESULTS: Of the 4947 patients admitted to the Division of Trauma during the study period, there were 231 (4.7%) deaths. The most common mechanisms of injuries were stab wounds (32.9 %), vehicular crashes (28.6 %), and gunshot wounds (25.5 %). Multiple organ failure/Sepsis (37.7 %) was the most frequent causes of death, followed by Exsanguinations (27.7 %), Central Nervous System failure (18.6 %) and other causes (10.8%). Forty four (66.7 %) of the 66 patients who died within the first 24 hours died from Exsanguinations, while 66 (61.1 %) of the 8 patients who died after 72 hours died from Multiple organ failure/Sepsis. CONCLUSIONS: Intentional causes of injury (i.e. penetrating interpersonal violence) caused the majority of trauma deaths in this series from the Philippine General Hospital. This highlights the need for prioritizing a public health approach to violence prevention in the Philippines. Further research must be conducted to identify risk factors for interpersonal violence. Early identification of lethal injuries that may cause exsanguinations and definitive control of hemorrhage should be the primary focus to prevent acute deaths, within 24 hours of admission. Further adjuncts to the definitive treatment of hemorrhage, the critical care of TBI and MOF/Sepsis are needed to reduce deaths occurring more than 72 hours after admission

Insect Growth Regulator (IGR) effects of Eucalyptus citriodora Hook (Myrtaceae)

In addition to eucalyptin the methanol extract from leaves of Eucalyptus citriodora (Myrtaceae) afforded the known compounds apigenin, chrysin, luteolin, naringenin, quercetin; together with betulinic acid, oleanolic, ursolic acid, and two remaining complex mixtures of unidentified flavonoids and triterpenes. These compounds together with triterpenes mixtures, hexane and ethyl acetate extracts showed antifeedant, insecticidal and insect growth regulatory activities against fall armyworm [Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)] an important pest of corn, and yellow mealworm [Tenebrio molitor (Coleoptera:Tenebrionidae)] a pest of stored grains. The most active compounds were chrysin, eucalyptin, quercetin, luteolin, and betulinic and oleanolic acids and the mixtures of flavonoids and triterpenes (M1 and M2). These compounds and mixtures had IGR activity between 0.2 to 5.0 μg/mL and insecticidal effects between 5.0 and 10.0 μg/mL.The extracts were insecticidal to larvae, with lethal doses between 20-100 μg/mL. These compounds appear to have selective effects on the pre-emergence metabolism of the Lepidoptera, since in all treatments of the larvae of S. frugiperda the pupation was shortened and this process showed precociousness in relation to control. Thus, these substances may be useful as potential natural insecticidal agents

SAVANNAH RIVER SITE R REACTOR DISASSEMBLY BASIN IN SITU DECOMMISSIONING

The US DOE concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate in tact, structurally sound facilities that are no longer needed for their original purpose of, i.e., generating (reactor facilities), processing(isotope separation facilities) or storing radioactive materials. The 105-R Disassembly Basin is the first SRS reactor facility to undergo the in-situ decommissioning (ISD) process. This ISD process complies with the105-R Disassembly Basin project strategy as outlined in the Engineering Evaluation/Cost Analysis for the Grouting of the R-Reactor Disassembly Basin at the Savannah River Site and includes: (1) Managing residual water by solidification in-place or evaporation at another facility; (2) Filling the below grade portion of the basin with cementitious materials to physically stabilize the basin and prevent collapse of the final cap - Sludge and debris in the bottom few feet of the basin will be encapsulated between the basin floor and overlying fill material to isolate if from the environment; (3) Demolishing the above grade portion of the structure and relocating the resulting debris to another location or disposing of the debris in-place; and (4) Capping the basin area with a concrete slab which is part of an engineered cap to prevent inadvertent intrusion. The estimated total grout volume to fill the 105-R Reactor Disassembly Basin is 24,424 cubic meters or 31,945 cubic yards. Portland cement-based structural fill materials were design and tested for the reactor ISD project and a placement strategy for stabilizing the basin was developed. Based on structural engineering analyses and work flow considerations, the recommended maximum lift height is 5 feet with 24 hours between lifts. Pertinent data and information related to the SRS 105-R-Reactor Disassembly Basin in-situ decommissioning include: regulatory documentation, residual water management, area preparation activities, technology needs, fill material designs and testing, and fill placement strategy. This information is applicable to decommissioning both the 105-P and 105-R facilities. The ISD process for the entire 105-P and 105-R reactor facilities will require approximately 250,000 cubic yards (191,140 cubic meters) of grout and 2,400 cubic yards (1,840 cubic meters) of structural concrete which will be placed over a twelve month period to meet the accelerated schedule ISD schedule. The status and lessons learned in the SRS Reactor Facility ISD process will be described