A gene spans the pseudoautosomal boundary in mice

The X and Y chromosomes of the mouse, like those of other mammals, are heteromorphic over most of their length, but at the distal ends of the chromosomes is a region of sequence identity, the pseudoautosomal region (PAR), where the chromosomes pair and recombine during male meiosis. The point at which the PAR diverges into X- and Y-specific sequences is called the pseudoautosomal boundary. We have completed a genomic walk from the X-specific Amelogenin gene to the PAR. Analysis of this region revealed that the pseudoautosomal boundary of mice is located within an intron of a transcribed gene that encodes a novel RING finger protein. The first three of the exons of the gene are located on the X chromosome whereas the 3′ exons of the gene are located on both X and Y chromosomes. This unusual arrangement may indicate that the gene is in a state of transition from pseudoautosomal to X-unique and provides evidence for a process of attrition of the pseudoautosomal region on the Y chromosome.

The Cambrian “explosion”: Slow-fuse or megatonnage?

Clearly, the fossil record from the Cambrian period is an invaluable tool for deciphering animal evolution. Less clear, however, is how to integrate the paleontological information with molecular phylogeny and developmental biology data. Equally challenging is answering why the Cambrian period provided such a rich interval for the redeployment of genes that led to more complex bodyplans.

The notion of the Cambrian pananimalia genome.

The toil by photosynthesizing cyanobacteria and blue-green algae of nearly three billion years appeared to have finally resulted in the sufficient accumulation of molecular oxygen. So, the stage was set for the emergence, at the ocean bottom, of diverse animals that were consumers of molecular oxygen. It now appears that this Cambrian explosion, during which nearly all the extant animal phyla have emerged, was of an astonishingly short duration, lasting only 6-10 million years. Inasmuch as only a 1% DNA base sequence change is expected in 10 million years under the standard spontaneous mutation rate, I propose that all those diverse animals of the early Cambrian period, some 550 million years ago, were endowed with nearly identical genomes, with differential usage of the same set of genes accounting for the extreme diversities of body forms. Some of the more pertinent genes that are thought to be included in the Cambrian pananimalia genome are as follows. (i) A gene for lysyloxidase that, in the presence of molecular oxygen, crosslinked collagen triple helices to produce ligaments and tendons, thus contributing to the stout bodies of the Cambrian animals. (ii) Genes for hemoglobin; these internal transporters of molecular oxygen are today seen sporadically in members of diverse animal phyla. (iii) The Pax-6 gene for eye formation; the eyes of a ribbon worm to a human are organized by this gene. In animals without eyes, the same gene organizes other sensory systems and organs. (iv) A series of Hox genes for the anterior-posterior (cranio-caudal) body plans: these genes are also present in all phyla of the kingdom Animalia.

Loss of sequences 3' to the testis-determining gene, SRY, including the Y pseudoautosomal boundary associated with partial testicular determination.

The condition termed 46,XY complete gonadal dysgenesis is characterized by a completely female phenotype and streak gonads. In contrast, subjects with 46,XY partial gonadal dysgenesis and those with embryonic testicular regression sequence usually present ambiguous genitalia and a mix of Müllerian and Wolffian structures. In 46,XY partial gonadal dysgenesis gonadal histology shows evidence of incomplete testis determination. In 46,XY embryonic testicular regression sequence there is lack of gonadal tissue on both sides. Various lines of evidence suggest that embryonic testicular regression sequence is a variant form of 46,XY gonadal dysgenesis. The sex-determining region Y chromosome gene (SRY) encodes sequences for the testis-determining factor. To date germ-line mutations in SRY have been reported in approximately 20% of subjects with 46,XY complete gonadal dysgenesis. However, no germ-line mutations of SRY have been reported in subjects with the partial forms. We studied 20 subjects who presented either 46,XY partial gonadal dysgenesis or 46,XY embryonic testicular regression sequence. We examined the SRY gene and the minimum region of Y-specific DNA known to confer a male phenotype. The SRY-open reading frame (ORF) was normal in all subjects. However a de novo interstitial deletion 3' to the SRY-ORF was found in one subject. Although it is possible that the deletion was unrelated to the subject's phenotype, we propose that the deletion was responsible for the abnormal gonadal development by diminishing expression of SRY. We suggest that the deletion resulted either in the loss of sequences necessary for normal SRY expression or in a position effect that altered SRY expression. This case provides further evidence that deletions of the Y chromosome outside the SRY-ORF can result in either complete or incomplete sex reversal.

The Impact of Sexual Boundary Violations in Supervision and Therapy: A Qualitative Study of a Trainee's First-Hand Account

This study involves a qualitative analysis of a doctoral-level psychology trainee's first-hand account of sexual attraction and boundary violations that occurred in her clinical supervision and psychotherapy. Concepts of power, gender, social performance theory, and relational framing are applied to two case examples, illustrating the differing demands on a trainee when her relationships were sexualized in two distinct professional contexts. Ramifications of supervisory exploitation and the impact of such an experience on a trainee's professional development are discussed. Recommendations are provided for improving psychology training programs' prevention and response efforts.

Geodynamic implications derived from Numidian-like distal turbidites deposited along the Internal–External Domain Boundary of the Betic Cordillera (S Spain)

New data reveal Early Burdigalian ‘Numidian-like lithofacies’ in successions of the internal (southernmost) part of the South Iberian Margin (SIM) and the south-western margin of the Mesomediterranean Microplate (MM). The well-known Numidian Formation was deposited in the external (Massylian) sub-domain of the Maghrebian Flysch Basin (a south-western branch of the Tethys Ocean). The anomalous occurrence of ‘Numidian-like lithofacies’ is induced by the particular Early Miocene palaeogeographical and geodynamic complexity of the sector. This consisted of a ‘triple point’ with a dextral transform fault between the SIM and the MM-Maghrebian Flysch Basin system. In this framework, the ageing of Iberian reliefs and the MM collapse, coupled with an African Margin upbulging, and a shortening of the Maghrebian Flysch Basin (both related to the subduction), could have resulted in the arrival of the Numidian depositional system from so far away.

Propagation of Dyakonon Wave-Packets at the Boundary of Metallodielectric Lattices

We rigorously analyze the propagation of localized surface waves that takes place at the boundary between a semi-infinite layered metal-dielectric (MD) nanostructure cut normally to the layers and a isotropic medium. It is demonstrated that Dyakonov-like surface waves (also coined dyakonons) with hybrid polarization may propagate in a wide angular range. As a consequence, dyakonon-based wave-packets (DWPs) may feature sub-wavelength beamwidths. Due to the hyperbolic-dispersion regime in plasmonic crystals, supported DWPs are still in the canalization regime. The apparent quadratic beam spreading, however, is driven by dissipation effects in metal.

A new boundary-based morphological model

Mathematical morphology addresses the problem of describing shapes in an n-dimensional space using the concepts of set theory. A series of standardized morphological operations are defined, and they are applied to the shapes to transform them using another shape called the structuring element. In an industrial environment, the process of manufacturing a piece is based on the manipulation of a primitive object via contact with a tool that transforms the object progressively to obtain the desired design. The analogy with the morphological operation of erosion is obvious. Nevertheless, few references about the relation between the morphological operations and the process of design and manufacturing can be found. The non-deterministic nature of classic mathematical morphology makes it very difficult to adapt their basic operations to the dynamics of concepts such as the ordered trajectory. A new geometric model is presented, inspired by the classic morphological paradigm, which can define objects and apply morphological operations that transform these objects. The model specializes in classic morphological operations, providing them with the determinism inherent in dynamic processes that require an order of application, as is the case for designing and manufacturing objects in professional computer-aided design and manufacturing (CAD/CAM) environments. The operators are boundary-based so that only the points in the frontier are handled. As a consequence, the process is more efficient and more suitable for use in CAD/CAM systems.

Implementation of non-local boundary layer schemes in the Regional Atmospheric Modeling System and its impact on simulated mesoscale circulations

This paper proposes the implementation of different non-local Planetary Boundary Layer schemes within the Regional Atmospheric Modeling System (RAMS) model. The two selected PBL parameterizations are the Medium-Range Forecast (MRF) PBL and its updated version, known as the Yonsei University (YSU) PBL. YSU is a first-order scheme that uses non-local eddy diffusivity coefficients to compute turbulent fluxes. It is based on the MRF, and improves it with an explicit treatment of the entrainment. With the aim of evaluating the RAMS results for these PBL parameterizations, a series of numerical simulations have been performed and contrasted with the results obtained using the Mellor and Yamada (MY) scheme, also widely used, and the standard PBL scheme in the RAMS model. The numerical study carried out here is focused on mesoscale circulation events during the summer, as these meteorological situations dominate this season of the year in the Western Mediterranean coast. In addition, the sensitivity of these PBL parameterizations to the initial soil moisture content is also evaluated. The results show a warmer and moister PBL for the YSU scheme compared to both MRF and MY. The model presents as well a tendency to overestimate the observed temperature and to underestimate the observed humidity, considering all PBL schemes and a low initial soil moisture content. In addition, the bias between the model and the observations is significantly reduced moistening the initial soil moisture of the corresponding run. Thus, varying this parameter has a positive effect and improves the simulated results in relation to the observations. However, there is still a significant overestimation of the wind speed over flatter terrain, independently of the PBL scheme and the initial soil moisture used, even though a different degree of accuracy is reproduced by RAMS taking into account the different sensitivity tests.

Pseudo-organic structures from the Precambrian Bass limestone in Arizona / [by] Matthew H. Nitecki --

v.23:no.1(1971)

An illustrated flora of the northern United States, Canada and the British possessions, from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian, by Nathaniel Lord Britton ... and Hon. Addison Brown ...

v. 1

The Ontario-Manitoba Boundary Dispute

The powers of the General Government are so much greater than those of the United States in its relations with the Local Governments, that the central power must win. The next quarter century was marked by struggle, or rather a series of struggles, between the Dominion Government and those of the various provinces with as a general rule contrary to Macdonal's expectations, the latter proving successful. Ontario was the most consistent opponent of centralizing tendencies; her most notably victory was scored in what is known as the Ontario-Manitoba Boundary Dispute. It is out intention to deal with this question primarily as a phase of post-Confederation politics.

Tectonic evolution of the Proterozoic Itremo Group metasediments in central Madagascar

The major geologic units of the Itremo region in central Madagascar include: (1) upper amphibolite to granulite facies (higher grade) Precambrian rocks, mainly para- and orthogneisses, and migmatites; (2) the newly defined Itremo Nappes, a fold-and-thrust belt containing the Proterozoic Itremo Group sediments, metamorphosed at greenschist to lower amphibolite facies (lower grade) conditions: (3) Middle Neoproterozoic and Late Neoproterozoic-Cambrian intrusives. The stratigraphic succession of the Itremo Group in the eastern part of the Itremo region is, from bottom to top: quartzites, metapelites, metacarbonates and metapelites overlain by metacarbonates. During D1 the Itremo Group sediments were detached from their continental substratum, deformed into a fold-and-thrust nappe (Itremo Nappes), and transported on top of higher grade rocks that are intruded by Middle Neoproterozoic (c. 797–780 Ma) granites and gabbros. A second phase of deformation shortening (D2) affected both the Itremo Sedimentary Nappes and structurally underlying higher-grade rocksunits, and formed large-scale N-S-trending F2 folds. S1 axial plane foliations in Itremo Group sediments are truncated by Late Neoproterozoic-Cambrian granites (c. 570–540 Ma). The age of the formation of the Itremo Nappes is not well constrained: they formed in Neoproterozoic times between 780 and 570 Ma.