Anteroposterior length of the maxillary complex and its relationship with the anterior cranial base:

ABSTRACT Objectives To use both absolute anteroposterior maxillary complex length (APMCL) and relative APMCL to investigate the relationship between the maxillary complex, its individual bony segments, and their association to the anterior cranial base. In addition, the relationship between length and position of the maxillary complex was analyzed. Materials and Methods Sixty human skulls were analyzed using cone beam computed tomography. The maxillary complex length was measured between anterior and posterior nasal spine (ans-pns), and the average was used as the cut-off to identify a high- and a low-length group based on absolute APMCL. The length ratio between the maxillary complex and the anterior cranial base (ans-pns/SN) was used to identify the two groups based on relative APMCL. The anterior cranial base length and the lengths of the maxillary complex bones were compared between the high- and low-length groups. Results Based on absolute APMCL, individuals with shorter maxillary complex had shorter anterior cranial base (P = .003), representing normal proportions. Based on relative APMCL, individuals with shorter maxillary complex had longer anterior cranial base and vice versa (P = .014), indicating disproportions. Individuals with shorter maxillary complex exhibited shorter maxilla (Δ = −1.5 mm, P = .014). Conclusions When skeletal deformity of the midface is suspected, individual disproportions in the anteroposterior length of the maxillary complex in relation to the anterior cranial base (relative measurements) should be assessed through radiological imaging. A shorter maxillary complex may be associated with a shorter maxilla, and not with a shorter premaxilla or palatine bone.

Sexual dimorphism of synaptonemal complex length in threespine stickleback fish

Crossover frequency often differs substantially between sexes (i.e. heterochiasmy). Although this phenomenon is widespread throughout taxa, the mechanisms that lead to heterochiasmy remain unclear. One pattern that has emerged is that the overall length of the synaptonemal complex likely has a direct influence on the total number of crossovers in each sex. However, this has only been investigated in a handful of species. The threespine stickleback fish (Gasterosteus aculeatus) is an excellent species to explore whether synaptonemal complex length is associated with a difference in the total number of crossovers, as females have longer linkage maps than males. We used immunocytogenetics to quantify synaptonemal complex length in late pachytene female and male meiocytes. We found that females had synaptonemal complexes that were 1.65 times longer than males, which is remarkably similar to the length difference observed in a sex-specific linkage map constructed from a cross between two other populations. Our results support a model where chromosome axis length determines overall crossover frequency and establish the threespine stickleback as a useful species to explore the mechanistic basis of heterochiasmy.

Effect of Operating Factors on Reliability of Stoping Complexes and Assessment of Reliability of their Elements

For analyzing the dependence of face equipment failure on its length, two groups of elements are commonly considered. The first group includes all elements of shearer-loaders: conveyor drives, elements of pumping stations of powered supports, supports of face junctions with strikes and others. The second group includes all elements of powered support sections, linear sections of pan lines and scrapers of face scraper conveyors, electric cables of shearer-loaders, main pipelines of powered supports, etc. It is noted that the constancy of number of the first group elements linear variability of number of the second group elements do not uniquely determine the constancy or variability of the failure factor of the aggregate of the same type elements of the first or the second groups [1]. The plot of mean-time-between-failures (MTBF) of SL-500S stoping complex as function of face length is presented. Besides, the curve of the face (complex) length-dependence of average recovery) time (after failure of the SL-500S stoping complex time is shown. Analyzing the dependence of availability factor of stoping complexes on the face length showed that the length of stoping complexes is not a factor determining decrease in the MTBF and increase in the average recovery time. The plot of recovery time (after failure) of the SL-500S stoping complex as function of face length is shown. A formula is presented for assessing the cumulative effect, on the MTBF of SL500S stoping complex, of its length and potash ore cuttability. The plot of correlation between the MTBF of SL500S stoping complex and the face length/the potash ore cuttability is presented, which demonstrates that the complex length followed by the thickness of the extracted layer produce the greatest effect on the MTBF. The plot of the number of failures per day as a function of the maintenance factor of the SL-500C shearer-loader is presented. The plot demonstrates that the average number of failures of the SL-500C shearer-loader per day reaches a minimum and practically stabilize at values of the maintenance factor of 0.9–1.0, which correspond to three-shift production with one 6-hour maintenance shift per day.

Modelling Sex-Specific Crossover Patterning in Arabidopsis

“Interference” is a major force governing the patterning of meiotic crossovers. A leading model describing how interference influences crossover patterning is the beam-film model, a mechanical model based on the accumulation and redistribution of crossover-promoting “stress” along the chromosome axis. We use the beam-film model in conjunction with a large Arabidopsis reciprocal backcross data set to gain “mechanistic” insights into the differences between male and female meiosis, and crossover patterning. Beam-film modeling suggests that the underlying mechanics of crossover patterning and interference are identical in the two sexes, with the large difference in recombination rates and distributions able to be entirely explained by the shorter chromosome axes in females. The modeling supports previous indications that fewer crossovers occur via the class II pathway in female meiosis and that this could be explained by reduced DNA double-strand breaks in female meiosis, paralleling the observed reduction in synaptonemal complex length between the two sexes. We also demonstrate that changes in the strength of suppression of neighboring class I crossovers can have opposite effects on “effective” interference depending on the distance between two genetic intervals.

Modelling sex-specific crossover patterning in Arabidopsis

ABSTRACTInterference is a major force governing the patterning of meiotic crossovers. A leading model describing how interference influences crossover-patterning is the beam film model, a mechanical model based on the accumulation and redistribution of crossover-promoting stress along the chromosome axis. We use the beam-film model in conjunction with a large Arabidopsis reciprocal back-cross data set to gain mechanistic insights into the differences between male and female meiosis and crossover patterning. Beam-film modelling suggests that the underlying mechanics of crossover patterning and interference are identical in the two sexes, with the large difference in recombination rates and distributions able to be entirely explained by the shorter chromosome axes in females. The modelling supports previous indications that fewer crossovers occur via the class II pathway in female meiosis and that this could be explained by reduced DNA double strand breaks in female meiosis, paralleling the observed reduction in synaptonemal complex length between the two sexes. We also demonstrate that changes in the strength of suppression of neighboring class I crossovers can have opposite effects on effective interference depending on the distance between two genetic intervals.

Constructing 1-cusped isospectral non-isometric hyperbolic 3-manifolds

We construct infinitely many examples of pairs of isospectral but non-isometric [Formula: see text]-cusped hyperbolic [Formula: see text]-manifolds. These examples have infinite discrete spectrum and the same Eisenstein series. Our constructions are based on an application of Sunada’s method in the cusped setting, and so in addition our pairs are finite covers of the same degree of a 1-cusped hyperbolic 3-orbifold (indeed manifold) and also have the same complex length spectra. Finally we prove that any finite volume hyperbolic 3-manifold isospectral to the figure-eight knot complement is homeomorphic to the figure-eight knot complement.