Some nonparametric tests for randomness in sequences

Some nonparametric tests for randomness in sequence

The Changes They are A-Timed: Metabolism, Endogenous Clocks, and the Timing of Puberty

Childhood obesity has increased dramatically over the last several decades, particularly in industrialized countries, often accompanied by acceleration of pubertal progression and associated reproductive abnormalities (Biro et al., 2006; Rosenfield et al., 2009). The timing of pubertal initiation and progression in mammals is likely influenced by nutritional and metabolic state, leading to the hypothesis that deviations from normal metabolic rate, such as those seen in obesity, may contribute to observed alterations in the rate of pubertal progression. While several recent reviews have addressed the effects of metabolic disorders on reproductive function in general, this review will explore previous and current models of pubertal timing, outlining a potential role of endogenous timing mechanisms such as cellular circadian clocks in the initiation of puberty, and how these clocks might be altered by metabolic factors. Additionally, we will examine recently elucidated neuroendocrine regulators of pubertal progression such as kisspeptin, explore models detailing how the mammalian reproductive axis is silenced during the juvenile period and reactivated at appropriate developmental times, and emphasize how metabolic dysfunction such as childhood obesity may alter timing cues that advance or delay pubertal progression, resulting in diminished reproductive capacity

Phylogenetics of the boid snake genus Epicrates and Caribbean vicariance theory

http://deepblue.lib.umich.edu/bitstream/2027.42/57151/1/OP715.pd

Cre/lox generation of a novel whole-body Kiss1r KO mouse line recapitulates a hypogonadal, obese, and metabolically-impaired phenotype.

Kisspeptin and its receptor, Kiss1r, act centrally to stimulate reproduction. Recent evidence indicates that kisspeptin is also important for body weight and metabolism, as whole-body Kiss1r KO mice, developed with gene trap technology, display obesity and reduced metabolism. Kiss1r is expressed in brain and multiple peripheral tissues, but it is unknown which is responsible for the metabolic phenotype. Here, we sought to confirm that 1) the metabolic phenotype of the gene trap Kiss1r KOs is due to disruption of kisspeptin signaling and not off-target effects of viral mutagenesis, and 2) the Kiss1r flox line is suitable for creating conditional KOs to study the metabolic phenotype. We used Cre/lox technology (Zp3-Cre/Kiss1r flox) to develop a new global Kiss1r KO ("Kiss1r gKO") to compare with the original gene trap KO phenotype. We confirmed that deleting exon 2 of Kiss1r from the entire body induces hypogonadism in both sexes. Moreover, global deletion of Kiss1r induced obesity in females, but not males, along with increased adiposity and impaired glucose tolerance, similar to the gene trap Kiss1r KOs. Likewise, Kiss1r gKO females had decreased VO2 and VCO2, likely underlying their obesity. These findings support that our previous results in gene trap Kiss1r KOs are due to disrupted kisspeptin signaling, and further highlight a role for Kiss1r signaling in energy expenditure and metabolism besides controlling reproduction. Moreover, given Kiss1r expression in multiple cell-types, our findings indicate that the Kiss1r flox line is viable for future investigations to isolate specific target cells of kisspeptin's metabolic effects

The X square statistic and goodness of fit test

The X square statistic is a useful measure of the discrepancy between the actual distribution of a set of data points and the theoretical distribution of a random variable of which the data points supposedly are values. Thus the X square statistic is frequently used in goodness of fit tests

Effects of Selective Deletion of Tyrosine Hydroxylase from Kisspeptin Cells on Puberty and Reproduction in Male and Female Mice.

The neuropeptide kisspeptin, encoded by Kiss1, regulates reproduction by stimulating GnRH secretion. Kiss1-syntheizing neurons reside primarily in the hypothalamic anteroventral periventricular (AVPV/PeN) and arcuate (ARC) nuclei. AVPV/PeN Kiss1 neurons are sexually dimorphic, with females expressing more Kiss1 than males, and participate in estradiol (E2)-induced positive feedback control of GnRH secretion. In mice, most AVPV/PeN Kiss1 cells coexpress tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis (in this case, dopamine). Dopamine treatment can inhibit GnRH neurons, but the function of dopamine signaling arising specifically from AVPV/PeN Kiss1 cells is unknown. We generated a novel TH flox mouse and used Cre-Lox technology to selectively ablate TH specifically from Kiss1 cells. We then examined the effects of selective TH knock-out on puberty and reproduction in both sexes. In control mice, 90% of AVPV/PeN Kiss1 neurons coexpressed TH, whereas in mice lacking TH exclusively in Kiss1 cells (termed Kiss THKOs), TH was successfully absent from virtually all Kiss1 cells. Despite this absence of TH, both female and male Kiss THKOs displayed normal body weights, puberty onset, and basal gonadotropin levels in adulthood, although testosterone (T) was significantly elevated in adult male Kiss THKOs. The E2-induced LH surge was unaffected in Kiss THKO females, and neuronal activation status of kisspeptin and GnRH cells was also normal. Supporting this, fertility and fecundity were normal in Kiss THKOs of both sexes. Thus, despite high colocalization of TH and Kiss1 in the AVPV/PeN, dopamine produced in these cells is not required for puberty or reproduction, and its function remains unknown

Gordian Adjacency for Positive Braid Knots

A knot $K_1$ is said to be Gordian adjacent to a knot $K_2$ if $K_1$ is an intermediate knot on an unknotting sequence of $K_2$. We extend previous results on Gordian adjacency by showing sufficient conditions for Gordian adjacency between classes of positive braid knots through manipulations of braid words. In addition, we explore unknotting sequences of positive braid knots and give a proof that there are only finitely many positive braid knots for a given unknotting number

Autonomous Aerobraking Development Software: Phase 2 Summary

NASA has used aerobraking at Mars and Venus to reduce the fuel required to deliver a spacecraft into a desired orbit compared to an all-propulsive solution. Although aerobraking reduces the propellant, it does so at the expense of mission duration, large staff, and DSN coverage. These factors make aerobraking a significant cost element in the mission design. By moving on-board the current ground-based tasks of ephemeris determination, atmospheric density estimation, and maneuver sizing and execution, a flight project would realize significant cost savings. The NASA Engineering and Safety Center (NESC) sponsored Phase 1 and 2 of the Autonomous Aerobraking Development Software (AADS) study, which demonstrated the initial feasibility of moving these current ground-based functions to the spacecraft. This paper highlights key state-of-the-art advancements made in the Phase 2 effort to verify that the AADS algorithms are accurate, robust and ready to be considered for application on future missions that utilize aerobraking. The advancements discussed herein include both model updates and simulation and benchmark testing. Rigorous testing using observed flight atmospheres, operational environments and statistical analysis characterized the AADS operability in a perturbed environment

Agony at a Distance : Investigating Digital Witnessing on YouTube

Peer reviewe