Numerical study of linear and circular model DNA chains confined in a slit: metric and topological properties

Advanced Monte Carlo simulations are used to study the effect of nano-slit confinement on metric and topological properties of model DNA chains. We consider both linear and circularised chains with contour lengths in the 1.2--4.8 $\mu$m range and slits widths spanning continuously the 50--1250nm range. The metric scaling predicted by de Gennes' blob model is shown to hold for both linear and circularised DNA up to the strongest levels of confinement. More notably, the topological properties of the circularised DNA molecules have two major differences compared to three-dimensional confinement. First, the overall knotting probability is non-monotonic for increasing confinement and can be largely enhanced or suppressed compared to the bulk case by simply varying the slit width. Secondly, the knot population consists of knots that are far simpler than for three-dimensional confinement. The results suggest that nano-slits could be used in nano-fluidic setups to produce DNA rings having simple topologies (including the unknot) or to separate heterogeneous ensembles of DNA rings by knot type.Comment: 12 pages, 10 figure

Salmon mortality investigation

On 1 March 2012, the New Zealand King Salmon Company (NZKS) notified MPI of a significant mortality event occurring in Chinook salmon (Oncorhynchus tshawytscha) at their sea farm in Waihinau Bay, outer Pelorus Sound

Repulsive Forces Between Looping Chromosomes Induce Entropy-Driven Segregation

One striking feature of chromatin organization is that chromosomes are compartmentalized into distinct territories during interphase, the degree of intermingling being much smaller than expected for linear chains. A growing body of evidence indicates that the formation of loops plays a dominant role in transcriptional regulation as well as the entropic organization of interphase chromosomes. Using a recently proposed model, we quantitatively determine the entropic forces between chromosomes. This Dynamic Loop Model assumes that loops form solely on the basis of diffusional motion without invoking other long-range interactions. We find that introducing loops into the structure of chromatin results in a multi-fold higher repulsion between chromosomes compared to linear chains. Strong effects are observed for the tendency of a non-random alignment; the overlap volume between chromosomes decays fast with increasing loop number. Our results suggest that the formation of chromatin loops imposes both compartmentalization as well as order on the system without requiring additional energy-consuming processes

Best Practices for Queer Metadata

This document is the result of two years of work by a group of nearly one hundred knowledge organisers, cataloguers, librarians, archivists, scholars, and information professionals with a concerted interest in improving the metadata treatment of queer people, communities, and items in GLAMS (Galleries, Libraries, Archives, Museums, and Special Collections) and other informational institutions. Their work has been supported by over 800 peer reviewers; combined, these groups make up the Queer Metadata Collective (QMDC). The QMDC builds upon earlier work done by the Trans Metadata Collective (TMDC), a similarly-organised group of metadata workers and information professionals with a concerted interest in improving the metadata representation of trans and gender-diverse people. The work of the TMDC culminated in Metadata Best Practices for Trans and Gender Diverse Resources, focusing on the description, cataloguing, and classification of information resources as well as the creation of metadata about trans and gender-diverse people, including authors, communities, and other creators. Following the publication of the Best Practices, several TMDC members founded and developed the QMDC over the summer of 2022. This document focuses on metadata by and about queer people, communities, and resources. While there is significant overlap between queer metadata and trans and gender diverse metadata, QMDC’s recommendations should not be seen as excluding or superseding TMDC’s, as trans and gender diverse people, communities, and resources have specific needs. For best practices and recommendations about trans and gender-diverse resources, please consult the TMDC document. If the TMDC and QMDC recommendations conflict (we are not aware of any instances in which they do), prefer the TMDC document for trans and gender diverse resources and the QMDC for other types of queer resources.UT Librarie

A history and description of the modern dogs of Great Britain and Ireland. Sporting division ...

Mode of access: Internet

A history and description of the modern dogs of Great Britain and Ireland. Sporting division ...

Mode of access: Internet