T4 DNA ligase is a widely used ligase in many applications; yet in single nucleotide polymorphism analysis, it has been found generally lacking owing to its tendency to ligate mismatches quite efficiently. To address this lack of selectivity, we explored the effect of temperature on the selectivity of the ligase in discriminating single base pair mismatches at the 3'-terminus of the ligating strand using short ligation probes (9-mers). Remarkably, we observe outstanding selectivities when the assay temperature is increased to 7 °C to 13 °C above the dissociation temperature of the matched probetarget duplexes using commercially available enzyme at low concentration. Higher enzyme concentration shifts the temperature range to 13 °C to 19 °C above the probetarget dissociation temperatures. Finally, substituting the 5'-phosphate terminus with an abasic nucleotide decreases the optimal temperature range to 7 °C to 10 °C above the matched probetarget duplex. We compare the temperature dependence of the T4 DNA ligase catalyzed ligation and a nonenzymatic ligation system to contrast the origin of their modes of selectivity. For the latter, temperatures above the probetarget duplex dissociation lead to lower ligation conversions even for the perfect matched system. This difference between the two ligation systems reveals the uniqueness of the T4 DNA ligase's ability to maintain excellent ligation yields for the matched system at elevated temperatures. Although our observations are consistent with previous mechanistic work on T4 DNA ligase, by mapping out the temperature dependence for different ligase concentrations and probe modifications, we identify simple strategies for introducing greater selectivity into SNP discrimination based on ligation yields.Within populations, adult sex ratios influence population growth and extinction risk, mating behaviours and parental care. Sex ratio adjustment can also have pronounced effects on individual fitness. Accordingly, it is important that we understand how often, and why, offspring sex ratios deviate from parity. In Drosophila melanogaster, females appear to improve their fitness by producing fewer sons when paired with older males. However, facultative sex ratio adjustment in D. melanogaster is controversial, and our understanding of how sex ratio skew affects fitness is hampered by pronounced sexual conflict in this species. see more Additionally, it is unclear whether maternal age or quality interacts with paternal age to influence offspring sex ratios. Here, we test whether offspring sex ratios vary as a function of maternal quality, and maternal and paternal age in Drosophila simulans, a sister species of D. melanogaster that lacks overt sexual conflict. We find that offspring sex ratios are slightly male-biased overall, but constant across the female life course, and independent of female quality, or paternal age. To really understand if, how and when females skew offspring sex ratios, we need studies linking offspring sex ratios to paternal and maternal phenotypes that are predicted to shift optimal investment in sons and daughters.The adaptive significance of temperature-dependent sex determination (TSD) in reptiles remains unknown decades after TSD was first identified in this group. Concurrently, there is growing concern about the effect that rising temperatures may have on species with TSD, potentially producing extremely biased sex ratios or offspring of only one sex. The current state-of the-art in TSD research on sea turtles is reviewed here and, against current paradigm, it is proposed that TSD provides an advantage under warming climates. By means of coadaptation between early survival and sex ratios, sea turtles are able to maintain populations. When offspring survival declines at high temperatures, the sex that increases future fecundity (females) is produced, increasing resilience to climate warming. TSD could have helped reptiles to survive mass extinctions in the past via this model. Flaws in research on sex determination in sea turtles are also identified and it is suggested that the development of new techniques will revolutionize the field.The postnatal period is a time of increased brain development and plasticity which have enduring influences on brain and behavior. Infants demonstrate a transient surge in testosterone (T) during development referred to as "mini puberty". The utility of studying mini puberty in psychobiology has only recently emerged. Life-history theory postulates that infants "use" the maternal environment-pre and postnatally-to calibrate growth and timing of sexual maturity. As such, variability in infant T levels is not arbitrary and can be predicted by theory. We examine the role of maternal pre- and postnatal cortisol. Using saliva samples (n = 193 dyads), we predicted that higher levels of maternal cortisol are associated with higher levels of infant T. We found only maternal postnatal cortisol had a relationship with infants' mini puberty. This relationship was in the predicted direction and remained after controlling for numerous variables. Discussion will include the potential role of mini puberty as an inflection point where systems related to growth, sexual maturation, and psychosexual behavior can be calibrated and coordinated.Latent trajectory class analysis is a powerful technique to elucidate the structure underlying population heterogeneity. The standard approach relies on fully parametric modeling and is computationally impractical when the data include a large collection of non-Gaussian longitudinal features. We introduce a new approach, the first based on artificial likelihood concepts, that avoids undue modeling assumptions and is computationally tractable. We show that this new method provides reliable estimates of the underlying population structure and is from 20 to 200 times faster than conventional methods when the longitudinal features are non-Gaussian. We apply the approach to explore subgroups among research participants in the early stages of neurodegeneration. Pacemaker used in small children typically consist of an abdominally placed generator and epicardially affixed leads, making such a system prone to lead dysfunction during growth. Aim of this study was to investigate the feasibility of epicardial pacing with a leadless pacemaker in a lamb model. Seventeen lambs underwent epicardial implantation of a Micra transcatheter pacing system (TPS) (Medtronic, Minneapolis, MN, USA) via left-lateral thoracotomy to the left ventricle (LV) surface (n=11/17) and to the left atrial appendage (n=6). Ventricular devices were fixated with the tines within the pericardium, whereas the tines of the atrial devices penetrated the myocardium of the left atrial appendage. After 31weeks, animals were sacrificed and hearts were explanted for histological analysis. Following implantation, median P/R amplitude was 4.25/5.5mV while median pacing threshold was 1.1/1.9V at 0.24ms. After 31weeks, median P/R amplitude was 3.3/4.2mV. Median atrial pacing threshold was 0.5/0.24ms. Eight of 10 ventricular pacemakers had lost capture at standard impulse width even at maximum impulse amplitude.