The ghost sex-life of the paedogenetic beetle Micromalthus debilis

Genetic and sexual systems can be evolutionarily dynamic within and among clades. However, identifying the processes responsible for switches between, for instance, sexual and asexual reproduction, or cyclic and non-cyclic life histories remains challenging. When animals evolve parthenogenetic reproduction, information about the sexual mating system becomes lost. Here we report an extraordinary case where we have been able to resurrect sexual adults in a species of beetle that reproduces by parthenogenetic paedogenesis, without the production of adults. Via heat treatment, we were able to artificially induce adult beetles of Micromalthus debilis in order to describe its pre-paedogenetic mating system. Adults showed a highly female biased sex ratio, out-breeding behaviour, and sex-role reversal. Paedogenetic larvae of Micromalthus are infected with the endosymbiotic bacteria Rickettsia and Wolbachia. Clear signs of vestigialization in adults are concurrent with the loss of adults. Our data suggest an ancient female sex ratio bias that predated the loss of adults, perhaps associated with endosymbionts. We propose a model for the transition from a haplodiploid cyclical parthenogenetic life history to parthenogenetic paedogenesis. Paedogenetic development induces a new mechanism of sex ratio bias in midges, wasps and beetles

Short-course High-dose Liposomal Amphotericin B for Human Immunodeficiency Virus–associated Cryptococcal Meningitis: A Phase 2 Randomized Controlled Trial

Background We performed a phase 2 noninferiority trial examining the early fungicidal activity (EFA) of 3 short-course, high-dose liposomal amphotericin B (L-AmB) regimens for cryptococcal meningitis (CM) in Tanzania and Botswana. Methods Human immunodeficiency virus (HIV)-infected adults with CM were randomized to (i) L-AmB 10 mg/kg on day 1 (single dose); (ii) L-AmB 10 mg/kg on day 1 and 5 mg/kg on day 3 (2 doses); (iii) L-AmB 10 mg/kg on day 1 and 5 mg/kg on days 3 and 7 (3 doses); or (iv) L-AmB 3 mg/kg/day for 14 days (control). All patients also received oral fluconazole 1200 mg/day for 14 days. Primary endpoint was mean rate of clearance of cerebrospinal fluid cryptococcal infection (EFA). Noninferiority was defined as an upper limit of the 2-sided 95% confidence interval (CI) of difference in EFA between intervention and control <0.2 log10 colony-forming units (CFU)/mL/day. Results Eighty participants were enrolled. EFA for daily L-AmB was –0.41 log10 CFU/mL/day (standard deviation, 0.11; n = 17). Difference in mean EFA from control was –0.11 (95% CI, –.29 to .07) log10 CFU/mL/day faster with single dose (n = 16); –0.05 (95% CI, –.20 to .10) log10 CFU/mL/day faster with 2 doses (n = 18); and –0.13 (95% CI, –.35 to .09) log10 CFU/mL/day faster with 3 doses (n = 18). EFA in all short-course arms was noninferior to control. Ten-week mortality was 29% (n = 23) with no statistical difference between arms. All arms were well tolerated. Conclusions Single-dose 10 mg/kg L-AmB was well tolerated and led to noninferior EFA compared to 14 days of 3 mg/kg/day L-AmB in HIV-associated CM. Induction based on a single 10 mg/kg L-AmB dose is being taken forward to a phase 3 clinical endpoint trial. Clinical Trials Registration ISRCTN 10248064

Sigma Point Filters for Dynamic Nonlinear Regime Switching Models

In this paper we take three well known Sigma Point Filters, namely the Unscented Kalman Filter, the Divided Difference Filter, and the Cubature Kalman Filter, and extend them to allow for a very general class of dynamic nonlinear regime switching models. Using both a Monte Carlo study and real data, we investigate the properties of our proposed filters by using a regime switching DSGE model solved using nonlinear methods. We find that the proposed filters perform well. They are both fast and reasonably accurate, and as a result they will provide practitioners with a convenient alternative to Sequential Monte Carlo methods. We also investigate the concept of observability and its implications in the context of the nonlinear filters developed and propose some heuristics. Finally, we provide in the RISE toolbox, the codes implementing these three novel filters