Deconvolution of isotope signals from bundles of multiple hairs

pre-printSegmental analysis of hair has been used in diverse fields ranging from forensics to ecology to measure the concentration of substances such as drugs and isotopes. Multiple hairs are typically combined into a bundle for segmental analysis to obtain a high-resolution series of measurements. Individual hair strands cycle through multiple phases of growth and grow at different rates when in the growth phase. Variation in growth of hair strands in a bundle can cause misalignment of substance concentration between hairs, attenuating the primary body signal. We developed a mathematical model based on the known physiology of hair growth to describe the signal averaging caused by bundling multiple hairs for segmental analysis. The model was used to form an inverse method to estimate the primary body signal from measurements of a hair bundle. The inverse method was applied to a previously described stable oxygen isotope chronology from the hair of a murder victim and provides a refined interpretation of the data. Aspects of the reconstruction were confirmed when the victim was later identified

Mathematical modeling of liver injury and dysfunction after acetaminophen overdose: early discrimination between survival and death

pre-printAcetaminophen is the leading cause of acute liver injury in the developed world. Timely administration of N-Acetylcysteine (N-Ac) prevents the progression of serious liver injury and disease, while failure to administer N-Ac within a critical time frame allows disease progression and in the most severe cases may result in liver failure or death. In this situation, liver transplantation may be the only life-saving measure. Thus, the outcome of an acetaminophen overdose depends upon the size of the overdose and the time to first administration of N-Ac. We developed a system of differential equations to describe acute liver injury due to acetaminophen overdose. The Model for Acetaminophen-induced Liver Damage (MALD) uses a patient's AST, ALT, and INR measurements on admission to estimate overdose amount, time elapsed since overdose, and outcome. The mathematical model was then tested on 53 patients from the University of Utah. With the addition of serum creatinine, eventual death was predicted with 100% sensitivity, 91% specificity, 67% PPV, and 100% NPV in this retrospective study. Using only initial AST, ALT, and INR measurements, the model accurately predicted subsequent laboratory values for the majority of individual patients. This is the first dynamical rather than statistical approach to determine poor prognosis in patients with life-threatening liver disease due to acetaminophen overdose. Conclusion: MALD provides a method to estimate overdose amount, time elapsed since overdose, and outcome from patient laboratory values commonly available on admission in cases of acute liver failure due to acetaminophen overdose and should be validated in multicentric prospective evaluation

Delegation and Time

Most concerns about delegation are put in terms of the handover of legislative power to federal agencies and the magnitude of the legislative policy decisions made by such agencies. Likewise, most reform proposals, such as the Congressional Review Act and the proposed REINS Act, address these gap-filling, democratic-deficit concerns. The same is true of the judicially created non-delegation canons, such as the major questions doctrine and other clear-statement rules. This Article addresses a different, under-explored dimension of the delegation problem: the temporal complications of congressional delegation. In other words, broad congressional delegations of authority at one time period become a source of authority for agencies to take action at a later time that was wholly unanticipated by the enacting Congress or could no longer receive legislative support. This problem has taken on added significance in the current era of congressional inaction.To address this distinct, temporal problem of delegation, we suggest that Congress revive the practice of regular reauthorization of statutes that govern federal regulatory action. In some circumstances, this will require Congress to consider adding reauthorization incentives, such as sun-setting provisions. In other regulatory contexts, Congress may well decide the costs of mandatory reauthorization outweigh the benefits. Nevertheless, we argue that Congress should more regularly use this longstanding legislative tool to mitigate the democratic deficits that accompany broad delegations of lawmaking authority to federal agencies and spur more regular legislative engagement with federal regulatory policy. A return to reauthorization would also strengthen the partnership between Congress and the administrative state as well as mitigate some of the major concerns that have been raised in recent years regarding Chevron deference

Reductions of lattice mKdV to qq-PVI\mathrm{P}_{VI}

This Letter presents a reduction of the lattice modified Korteweg-de-Vries equation that gives rise to a $q$-analogue of the sixth Painlev\'e equation. This new approach allows us to give the first ultradiscrete Lax representation of an ultradiscrete analogue of the sixth Painlev\'e equation.Comment: 4 page

Thermal Sensitivity of Swimming Performance and Muscle Contraction in Northern and Southern Populations of Tree Frogs (Hyla Crucifer)

The effects of temperature on sprint swimming ability and muscle contractile properties were examined in northern and southern populations of the holarctic tree frog, Hyla crucifer Wied-Neuwied, acclimated to 20–23°C. Maximal swimming velocities of 29 (southern) and 32 (northern) cms−1 and stroke frequencies of 4.1 (southern) and 5.5 (northern) strokes s-1 were attained at 30°C, and maximal stroke lengths (i.e. distance moved per stroke) of 8.0 (southern) and 7.4 (northern) cm at 20°C. The thermal dependence of swimming velocity decreases with increasing temperature (e.g. Q10 = 4.0 from 6 to 10°C, 1.2 from 20 to 30°C), as reported for locomotion in other ectothermic vertebrates. Over a temperature range of l.5-30°C, velocity increases by a factor of 5.5, frequency by a factor of 4, and length by a factor of 1.7. Thus, increased velocity at higher temperatures can be attributed mostly to increased stroke frequency; increments in stroke length contribute less. Muscle contractile properties have similar thermal dependencies to those of other vertebrates: rate processes [including twitch time-to-peak tension (TPT), twitch half-relaxation time (RT½), maximal rate of tetanic tension development and isotonic shortening velocity] are much more sensitive to temperature than is force generation (twitch and tetanic tension). Below 8°C, stroke frequency is limited by twitch contraction time (TPT + RT½), and leg extension in a swimming stroke by TPT. At higher temperatures, the thermal dependence of stroke time is lower than that of contraction time. Neither locomotor nor muscle contractile properties are different between the two populations (except for twitch tension at low temperatures). Inflexibility in the thermal dependence of muscle contraction and locomotion in this species may help to explain differences in breeding phenologies between northern and southern populations

Accelerating the Vero vaccine production platform through the generation of high-density cell banks and direct thaw into microcarrier bioreactor cultures

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A Modified Mole Cricket Lure and Description of Scapteriscus borellii (Orthoptera: Gryllotalpidae) Range Expansion and Calling Song in California

Invasive mole cricket species in the genus Scapteriscus have become significant agricultural pests and are continuing to expand their range in North America. Though largely subterranean, adults of some species, such as Scapteriscus borellii Giglio-Tos 1894, are capable of long dispersive flights and phonotaxis to male calling songs to find suitable habitats and mates. Mole crickets in the genus Scapteriscus are known to be attracted to and can be caught by audio lure traps that broadcast synthesized or recorded calling songs. We report improvements in the design and production of electronic controllers for the automation of semipermanent mole cricket trap lures as well as highly portable audio trap collection designs. Using these improved audio lure traps, we collected the first reported individuals of the pest mole cricket S. borellii in California. We describe several characteristic features of the calling song of the California population including that the pulse rate is a function of soil temperature, similar to Florida populations of S. borellii. Further, we show that other calling song characteristics (carrier frequency, intensity, and pulse rate) are significantly different between the populations

Hypothermia: an unusual indication for gastric lavage.

BACKGROUND: Previous reports suggest that gastric lavage holds many risks and is not routinely indicated for decontamination of the overdose patient. OBJECTIVE: To present a case of overdose with concurrent accidental hypothermia where gastric decontamination was utilized. CASE REPORT: A 50-year-old hypothermic, comatose patient was transported to the Emergency Department with a concurrent, massive medication ingestion diagnosed incidentally on a routine abdominal computed tomography scan. Both active and passive rewarming measures, in conjunction with gastric lavage and retrieval of multiple pill fragments, were performed, and the patient survived to hospital discharge without sequelae. Interestingly, the patient admitted to an intentional ingestion of both labetalol and lorazepam. CONCLUSION: Due to hypothermia-mediated changes in metabolism, including gastric atony and decreased hepatic metabolism, gastric lavage may provide additional benefit in the management of severely hypothermic patients with potentially lethal, massive pill ingestions

Chern-Simons and WZW Anomaly Cancelations Across Dimensions

The WZW functional in D=4 can be derived directly from the Chern-Simons functional of a compactified D=5 gauge theory and the boundary fermions it supplants. A simple pedagogical model based on U(1) gauge groups illustrates how this works. A bulk-boundary system with the fermions eliminated manifestly evinces anomaly cancelations between CS and WZW terms.Comment: 6 pages, ReVtex 4, no figure