Rapid field-cycling MRI using fast spin-echo

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Retreat from Boothia: The Original Diary of James Clark Ross, May to October 1832

Following the abandonment of John Ross's expedition ship Victory in Lord Mayor Bay in 1832, Ross's nephew and second-in-command, James Clark Ross, led a separate forward sledging group for much of the retreat to Somerset Island. While John Ross described the events of his own sledging group in his published narrative, he provided essentially no information on James Clark Ross's group. Recently, the journal kept by James Clark Ross during the retreat was located, and it forms the subject of this article. The journal covers the period from 4 May to 14 October 1832, during which the Victory was abandoned, an attempt (eventually aborted) made to escape using sledges and boats via Port Leopold, and preparations made to spend the winter of 1832-33 at Fury Beach.Key words: James Clark Ross, Boothia Peninsula and Somerset Island, 1832, unpublished diary, arctic explorationRÉSUMÉ. À la suite de l’abandon dans la baie Lord Mayor du navire Victory transportant l’expédition de John Ross en 1832, le neveu et commandant adjoint de Ross, James Clark Ross, dirigea un groupe séparé, équipé de traîneaux pendant la plus grande partie de sa retraite vers l’île Somerset. Si, dans le récit publié, John Ross relate ce qui est arrivé à son propre groupe voyageant aussi en traîneau, il n’a pratiquement pas fait mention du groupe de James Clark Ross. Le journal tenu par ce dernier au cours de la retraite a été découvert récemment et il constitue le sujet de cet article. Le journal couvre la période allant du 4 mai au 14 octobre 1832, durant laquelle le Victory fut abandonné, une tentative (qui finalement échoua) fut entreprise en vue d’atteindre Port Leopold en traîneau et en bateau, et des préparatifs furent menés pour passer l’hiver de 1832-1833 à Fury Beach.Mots clés: James Clark Ross, péninsule de Boothia et île Somerset, 1832, journal inédit, exploration arctiqu

'Round Lord Mayor Bay with James Clark Ross: The Original Diary of 1830

During John Ross's arctic expedition of 1829-33 in search of a northwest passage, approximately 1000 km of new coastline was mapped. Included in these new coastlines was Lord Mayor Bay on eastern Boothia Peninsula, which was surveyed by Ross's nephew and second-in-command, James Clark Ross, in 1830. The results of the Lord Mayor Bay survey effectively ended any chance of there being a northwest passage south and east of Somerset Island or west of northern Foxe Basin and northwest Hudson Bay. Despite the obvious importance of James Clark Ross's survey, it was not included in John Ross's published narrative of the expedition. The original diary has recently been located and is reproduced here, together with accompanying sketches and observations and a discussion of the circumstances of the survey.

Micrococcal Nuclease Does Not Substantially Bias Nucleosome Mapping

We have mapped sequence-directed nucleosome positioning on genomic DNA molecules using high-throughput sequencing. Chromatins, prepared by reconstitution with either chicken or frog histones, were separately digested to mononucleosomes using either micrococcal nuclease (MNase) or caspase-activated DNase (CAD). Both enzymes preferentially cleave internucleosomal (linker) DNA, although they do so by markedly different mechanisms. MNase has hitherto been very widely used to map nucleosomes, although concerns have been raised over its potential to introduce bias. Having identified the locations and quantified the strength of both the chicken or frog histone octamer binding sites on each DNA, the results obtained with the two enzymes were compared using a variety of criteria. Both enzymes displayed sequence specificity in their preferred cleavage sites, although the nature of this selectivity was distinct for the two enzymes. In addition, nucleosomes produced by CAD nuclease are 8–10 bp longer than those produced with MNase, with the CAD cleavage sites tending to be 4–5 bp further out from the nucleosomal dyad than the corresponding MNase cleavage sites. Despite these notable differences in cleavage behaviour, the two nucleases identified essentially equivalent patterns of nucleosome positioning sites on each of the DNAs tested, an observation that was independent of the histone type. These results indicate that biases in nucleosome positioning data collected using MNase are, under our conditions, not significant

Simple algorithm for the correction of MRI image artefacts due to random phase fluctuations

Grant support: This work was supported by EPSRC [grant numbers EP/E036775/1, EP/K020293/1] and received funding from the European Union's Horizon 2020 research and innovation programme [grant agreement No 668119, project “IDentIFY”]Peer reviewedPublisher PD

A new design concept for indraft wind-tunnel inlets with application to the national full-scale aerodynamic complex

The present inlet design concept for an indraft wind tunnel, which is especially suited to applications for which a specific test section flow quality is required with minimum inlet size, employs a cascade or vaneset to control flow at the inlet plane, so that test section total pressure variation is minimized. Potential flow panel methods, together with empirical pressure loss predictions, are used to predict inlet cascade performance. This concept has been used to develop an alternative inlet design for the 80 x 120-ft wind tunnel at NASA Ames Research Center. Experimental results show that a short length/diameter ratio wind tunnel inlet furnishing atmospheric wind isolation and uniform test section flow can be designed

Lateral cephalometric analysis of asymptomatic volunteers and symptomatic patients with and without bilateral temporomandibular joint disk displacement

Few studies of dentofacial and orthodontic structural relationships relative to temporomandibular joint (TMJ) dysfunction have been reported. We undertook this investigation to determine any correlation of orthodontic and dentofacial characteristics with TMJ bilateral disc displacement. The population of patients was selected from a TMJ clinic where a control group of asymptomatic volunteers had been previously established and standardized. Differences in skeletal structural features were determined among three study groups: (1) asymptomatic volunteers with no TMJ disk displacement, (2) symptomatic patients with no TMJ disc displacement, and (3) symptomatic patients with bilateral TMJ disk displacement. Thirty-two asymptomatic volunteers without disk displacement (25 female, 7 male) were compared with the same number each of symptomatic patients without TMJ disk displacement and symptomatic patients with bilateral TMJ disk displacement. All subjects had undergone a standardized clinical examination, bilateral TMJ magnetic resonance imaging, and lateral cephalometric radiographic analysis. The groups were matched according to sex, TMJ status, age, and Angle classification of malocclusion. Seventeen lateral cephalometric radiographic cranial base, maxillomandibular, and vertical dimension variables were evaluated and compared among the study groups. The mean angle of SNB, or the intersection of the sella-nasion plane and the nasion–point B line (indicating mandibular retrognathism relative to cranial base), of the symptomatic patients-with-displacement group was significantly smaller than that in the asymptomatic volunteers and symptomatic patients without bilateral disk displacement (p \u3c 0.05). Female subjects showed smaller linear measurements of mandibular length, lower facial height, and total anterior facial height than male subjects in all three groups (p \u3c 0.05). The mean angle of ANB, or the intersection of the nasion–point A and nasion–point B planes (indicating retrognathism of mandible relative to maxilla), was significantly greater in female than in male subjects, in all groups (p \u3c 0.05). Symptomatic patients with bilateral disk displacement had a retropositioned mandible, indicated by a smaller mean SNB angle compared with that in asymptomatic volunteers and symptomatic patients with no disk displacement on either side. Lateral cephalometric radiographic assessment may improve predictability of TMJ disk displacement in orthodontic patients but is not diagnostic; nor does the assessment explain any cause-and-effect relationship. (Am J Orthod Dentofacial Orthop 1998;114:248-55.

Connexin36 knockout mice display increased sensitivity to pentylenetetrazol-induced seizure-like behaviors

Large-scale synchronous firing of neurons during seizures is modulated by electrotonic coupling between neurons via gap junctions. To explore roles for connexin36 (Cx36) gap junctions in seizures, we examined the seizure threshold of connexin36 knockout (Cx36KO) mice using a pentylenetetrazol (PTZ) model

Efficient operators for studying higher partial waves

An extended multi-hadron operator is developed to extract the spectra of irreducible representations in the finite volume. The irreducible representations of the cubic group are projected using a coordinate-space operator. The correlation function of this operator is computationally efficient to extract lattice spectra. In particular, this new formulation only requires propagator inversions from two distinct locations, at fixed physical separation. We perform a proof-of-principle study on a $24^3 \times 48$ lattice volume with $m_\pi\approx 900$~MeV by isolating the spectra of $A^+_1$, $E^+$ and $T^+_2$ of the $\pi\pi$ system with isospin-2 in the rest frame.Comment: 8 pages, 3 figures, Contribution to the conference Lattice201