Delayed-Onset Malignant Hyperthermia in Association with Rocuronium Use

Purpose Two cases of malignant hyperthermia suspected to be related to the use of a nondepolarizing neuromuscular blocker are reported. Summary A pharmacogenetic disorder that may occur in as many as 1 in 3000 anesthesia procedures, malignant hyperthermia has been linked to the use of certain anesthetic gases and depolarizing neuromuscular blocking agents (e.g., succinylcholine). Although nondepolarizing neuromuscular blockers were cited as contributing to the development of malignant hyperthermia in a small number of published reports, the agents are generally considered safe for use in at-risk patients. Here investigators report two cases in which the nondepolarizing agent rocuronium is thought to have triggered malignant hyperthermia in patients with no known history of the disorder. In one case, a critically ill 27-year-old man undergoing an induced-hypothermia protocol developed a fever about 4 days after receiving rocuronium infusions, with temperatures rising over 11 days to a maximum of 105.2 °F. In the other case, a 63-year-old man being treated for serious complications of elective surgery developed extreme fever (maximum temperature of 107.1 °F) about 4 days after receiving two bolus doses and a continuous infusion of rocuronium. In both cases, the discontinuation of rocuronium therapy was followed by the rapid diminution of fever over 12–36 hours. After consultations with medical staff and consideration of other potential causal and contributory factors (e.g., neurologic injury, antimicrobial-induced fever), rocuronium was deemed the most likely trigger of the severe febrile response experienced by these two patients. Conclusion A 27-year-old man and a 63-year-old man received rocuronium and subsequently developed delayed-onset malignant hyperthermia, which resolved after the rocuronium was discontinued

Phased Tilings and Generalized Fibonacci Identities

Fibonacci numbers arise in the solution of many combinatorial problems. They count the number of binary sequences with no consecutive zeros, the number of sequences of 1\u27s and 2\u27s which sum to a given number, and the number of independent sets of a path graph. Similar interpretations exist for Lucas numbers. Using these interpretations, it is possible to provide combinatorial proofs that shed light on many interesting Fibonacci and Lucas identities (see [1], [3]). In this paper we extend the combinatorial approach to understand relationships among generalized Fibonacci numbers. Given G0 and G1 a generalized Fibonacci sequence G0, G1, G2,... is defined recursively by Gn = Gn-1 + Gn-2 for n ≥ 2. Two important special cases are the classical Fibonacci sequence Fn (F0 = 0 and F1 = 1) and the Lucas sequence Ln (L0 = 2 and L1 = 1). These sequences satisfy numerous relationships. Many are documented in Vajda [6], where, they are proved by algebraic means. Our goal is to recount these identities by combinatorial means. We introduce several combinatorial techniques which allow us to provide new proofs of nearly all the identities in [6] involving generalized Fibonacci numbers. We show that in the framework of phased tilings, these identities follow naturally as the tilings are counted, represented, and transformed in clever ways. These techniques are developed in the next several sections. In the final section, we discuss possible extensions

Robust velocity dispersion and binary population modeling of the ultra-faint dwarf galaxy Reticulum II

We apply a Bayesian method to model multi-epoch radial velocity measurements in the ultra-faint dwarf galaxy Reticulum II, fully accounting for the effects of binary orbital motion and systematic offsets between different spectroscopic datasets. We find that the binary fraction of Ret II is higher than 0.5 at the 90% confidence level, if the mean orbital period is assumed to be 30 years or longer. Despite this high binary fraction, we infer a best-fit intrinsic dispersion of 2.8$_{-1.2}^{+0.7}$ km/s, which is smaller than previous estimates, but still indicates Ret II is a dark-matter dominated galaxy. We likewise infer a $\lesssim$ 1% probability that Ret II's dispersion is due to binaries rather than dark matter, corresponding to the regime $M_{\odot}/L_{\odot} \lesssim$ 2. Our inference of a high close binary fraction in Ret II echoes previous results for the Segue 1 ultra-faint dwarf and is consistent with studies of Milky Way halo stars that indicate a high close binary fraction tends to exist in metal-poor environments.Comment: 9 pages, 5 figures, to be submitted to MNRA

Rocuronium and Malignant Hyperthermia

Authors response to a comment on: Beggs A, McCann J, Powers J. “Delayed-onset malignant hyperthermia in association with rocuronium use ” Am J Health-Syst Pharm 2012; 69:1128-34

Friends-Based Protective Strategies and Unwanted Sexual Experiences: A Daily Diary Examination of First Year College Women

Risk for unwanted sexual experiences can emerge in social contexts—the same contexts that early college women navigate with their friends. Though friends naturally engage in prevention strategies, less is known about how capable guardianship influences risk. Using multilevel structural equation modeling, the present study examined guardianship at the person and situation levels. First-year college women (N = 132) completed eight weekends of daily surveys. We examined whether guardianship (e.g., more friends present, greater proportion of female friends, no intoxicated friends) would reduce unwanted sexual experience risk and if this relation was mediated by friends-based strategy use. An alternative model was also tested with the same predictors, but with unwanted sexual experiences as the mediator and friends-based strategy use as the outcome. Over half (58%) of extended weekend nights with friends involved drinking or using drugs. Friends-based strategies were used on 29% of nights. Across models, being with one or more intoxicated friends was associated with friends-based strategy use and an unwanted sexual experience, but only at the situation level. Parents, educators, and policy makers can encourage college women to draw on their social networks to enhance safety. Interventions could incorporate more universal strategies for responding to risk in social contexts

Counting on Continued Fractions

No abstract provided in this article

Application of Paleoclimatology to Coral Reef Monitoring and Management

The skeletons of reef-building corals are valuable archives of climatic and environmental information. Paleoclimatic data chiefly have been generated in areas most sensitive to global or regional climatic variability. However, these records also provide valuable information on anthropogenic influences – guidance of value to resource managers. NOAA’s Coral Reef Watch targets observations of current and past coral reef health in or near marine protected areas through satellites, in situ sensor platforms, and paleoclimatic analyses. Paleoclimatic data provide retrospective monitoring through multi-century environmental reconstructions that improve our understanding of past stress to coral reefs. Two sites in the Florida Keys National Marine Sanctuary were the first to benefit from Coral Reef Watch Program paleoenvironmental analyses. Coral cores yielded direct measurements of δ18O, δ13C, Sr/Ca, and coral skeletal growth (extension, density, and calcification) and reconstructions of reef temperatures. Temperature reconstructions were compared with instrumental data from nearby stations and global data sets, while skeletal growth was used to infer responses to changing climatic and environmental conditions. Differences between paleoclimatic data and gridded datasets demonstrated that paleodata provide more accurate estimates of reef temperatures as they sample subsurface temperatures where the corals live. Because of relatively high thermal variability, at least 12 samples per year are needed at these sites. Further work will extend these records back in time, to new locations, and expand on the data reconstructed from the skeletal archives

Selenium hyperaccumulation offers protection from cell disruptor herbivores

<p>Abstract</p> <p>Background</p> <p>Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators <it>Stanleya pinnata </it>and <it>Astragalus bisulcatus </it>against two cell disrupting herbivores, the western flower thrips (<it>Frankliniella occidentalis</it>) and the two-spotted spider mite (<it>Tetranychus urticae</it>).</p> <p>Results</p> <p><it>Astragalus bisulcatus </it>and <it>S. pinnata </it>with high Se concentrations (greater than 650 mg Se kg^-1) were less subject to thrips herbivory than plants with low Se levels (less than 150 mg Se kg^-1). Furthermore, in plants containing elevated Se levels, leaves with higher concentrations of Se suffered less herbivory than leaves with less Se. Spider mites also preferred to feed on low-Se <it>A. bisulcatus </it>and <it>S. pinnata </it>plants rather than high-Se plants. Spider mite populations on <it>A. bisulcatus </it>decreased after plants were given a higher concentration of Se. Interestingly, spider mites could colonize <it>A. bisulcatus </it>plants containing up to 200 mg Se kg^-1dry weight, concentrations which are toxic to many other herbivores. Selenium distribution and speciation studies using micro-focused X-ray fluorescence (μXRF) mapping and Se K-edge X-ray absorption spectroscopy revealed that the spider mites accumulated primarily methylselenocysteine, the relatively non-toxic form of Se that is also the predominant form of Se in hyperaccumulators.</p> <p>Conclusions</p> <p>This is the first reported study investigating the protective effect of hyperaccumulated Se against cell-disrupting herbivores. The finding that Se protected the two hyperaccumulator species from both cell disruptors lends further support to the elemental defense hypothesis and increases the number of herbivores and feeding modes against which Se has shown a protective effect. Because western flower thrips and two-spotted spider mites are widespread and economically important herbivores, the results from this study also have potential applications in agriculture or horticulture, and implications for the management of Se-rich crops.</p