‘Fixed-axis’ magnetic orientation by an amphibian: non-shoreward-directed compass orientation, misdirected homing or positioning a magnetite-based map detector in a consistent alignment relative to the magnetic field?

Experiments were carried out to investigate the earlier prediction that prolonged exposure to long-wavelength (>500 nm) light would eliminate homing orientation by male Eastern red-spotted newts Notophthalmus viridescens. As in previous experiments, controls held in outdoor tanks under natural lighting conditions and tested in a visually uniform indoor arena under full-spectrum light were homeward oriented. As predicted, however, newts held under long-wavelength light and tested under either full-spectrum or long-wavelength light (>500 nm) failed to show consistent homeward orientation. The newts also did not orient with respect to the shore directions in the outdoor tanks in which they were held prior to testing. Unexpectedly, however, the newts exhibited bimodal orientation along a more-or-less `fixed' north-northeast—south-southwest magnetic axis. The orientation exhibited by newts tested under full-spectrum light was indistinguishable from that of newts tested under long-wavelength light, although these two wavelength conditions have previously been shown to differentially affect both shoreward compass orientation and homing orientation. To investigate the possibility that the `fixed-axis' response of the newts was mediated by a magnetoreception mechanism involving single-domain particles of magnetite, natural remanent magnetism (NRM) was measured from a subset of the newts. The distribution of NRM alignments with respect to the head—body axis of the newts was indistinguishable from random. Furthermore, there was no consistent relationship between the NRM of individual newts and their directional response in the overall sample. However, under full-spectrum, but not long-wavelength, light, the alignment of the NRM when the newts reached the 20 cm radius criterion circle in the indoor testing arena (estimated by adding the NRM alignment measured from each newt to its magnetic bearing) was non-randomly distributed. These findings are consistent with the earlier suggestion that homing newts use the light-dependent magnetic compass to align a magnetite-based `map detector' when obtaining the precise measurements necessary to derive map information from the magnetic field. However, aligning the putative map detector does not explain the fixed-axis response of newts tested under long-wavelength light. Preliminary evidence suggests that, in the absence of reliable directional information from the magnetic compass (caused by the 90° rotation of the response of the magnetic compass under long-wavelength light), newts may resort to a systematic sampling strategy to identify alignment(s) of the map detector that yields reliable magnetic field measurements

The Association between Vitamin D Receptor Expression and Prolonged Overall Survival in Breast Cancer.

Summary In this study, we analyzed vitamin D receptor (VDR) expression and survival in a breast cancer patient cohort of 82 breast cancer patients. Immunohistochemical analysis was possible in 91.5% of the patients (75/82). Staining was evaluated using the semi-quantitative assay according to Remmele and Stegner (immunoreactivity score [IRS]). IRS 0–1 was negative/very low, IRS 2–4 was moderate to high, and IRS 6–12 was high. Statistical analysis was performed by Spearman’s correlation test (p<0.05 significant). Overall survival was analyzed using Kaplan-Meier estimations. Only 6 patients had a negative IRS. Moderate IRS values were present in 20 patients. Most of the patients had a high IRS (49). For survival analysis, data were dichotomized (IRS 0–4: negative to moderate and IRS 6–12: high VDR expression). In univariate analysis, VDR expression showed significant differences in progression-free survival (PFS) and overall survival (OS). Patients with high IRS scores showed significantly better PFS and OS than patients with moderate/negative IRS scores for VDR expression. Tumor size was significantly correlated to PFS. When analyzed separately, the three different IRS groups showed significant differences in VDR expression. The present data suggest that VDR expression in breast cancer tissue may be of clinical significance, and the results provide evidence that VDR may be a factor with prognostic relevance. (J Histochem Cytochem 60:121–129, 2012). Keywords: breast cancer, vitamin D receptor, immunohistochemistry, prognosi

Electronic marking of physics assignments using a tablet PC

Producing and marking assignments electronically has advantages for both students and academic staff. However, marking and commenting on electronic assignments requires a simple and efficient method for annotating students’ scripts. We report here on a pilot project that provided associate lecturers (ALs) for a Level 2 Open University physics course with Tablet PCs and appropriate software that enabled them to input handwritten annotation, including equations and diagrams, to files containing students' solutions to assignments. Surveys of the views of ALs indicated that this method of electronic marking is effective and acceptable to students and to a large majority of ALs. It could be used to streamline assignment handling and marking procedures in campus universities as well as in distance learning contexts

Featured Session - Secrets of a Successful Transfer: Undergraduate Student Panel

This session will feature four undergraduates from around New England who have made the transition from a community college to a BA institution. The students will share insights on academics, student life, and support drawn from their own successful transfer stories

Community chaplaincy and crime prevention : blessing as a bridge from prison to community

Dans ce projet de recherche, nous examinons le dilemme des personnes empiégées dans le système judiciaire et nous identifions quelques causes possibles. Ensuite, des remèdes proactif et réactif sont proposés en adressant les causes de la criminalité. Dans la première partie, nous définissons l'aumônerie et nous racontons l'histoire du passé, ainsi l'actualité présente locale et nationale dans le Service correctionnel du Canada (SCC). Avec les références à l'Énoncé de la mission du SCC, quelques points de faiblesse et points forts sont soulignés. Deuxième partie, nous expliquons la cérémonie de la bénédiction dans l'Ancien Testament et nous l'adaptons et l'appliquons comme une thérapie afin d'aider des personnes empiégées dans les activités criminelles. Dans la troisième partie, nous proposons que l'église est l'endroit idéal pour l'implantation de telle bénédiction. La conclusion générale, nous regardons à toutes nos hypothèses et ajoutons quelques pensées pour réflexion future

Absolute spin-valve effect with superconducting proximity structures

We investigate spin dependent transport in hybrid superconductor(S)--normal-metal(N)--ferromagnet(F) structures under conditions of proximity effect. We demonstrate the feasibility of the absolute spin-valve effect for a certain interval of voltages in a system consisting of two coupled tri-layer structures. Our results are also valid for non-collinear magnetic configurations of the ferromagnets.Comment: 1 TEX file, 2 Postscript files. Accepted for publication in Physical Review Letter

Using Explosions to Power a Soft Robot

This manuscript describes the use of explosions to power a soft robot—one composed solely of organic elastomers (e.g., silicones). The robot has three pneumatic actuators (pneu-nets) in a tripedal configuration. Explosion of a stoichiometric mixture of methane and oxygen within the microchannels making up the actuators produced hot gas that rapidly inflated the pneu-nets, and caused the robot to launch itself vertically from a flat surface (e.g., to jump). A soft flap embedded in the pneu-net acted as the valve of a passive exhaust system, and allowed multiple sequential actuations. The flame and temperature increase from the explosions are short-lived, and do not noticeably damage the robots over dozens of actuation cycles.Chemistry and Chemical Biolog

LOW TEMPERATURE DOLOMITE SYNTHESIS: REACTION KINETICS, UREA CATALYSIS AND ISOTOPIC ANALYSES

Dolomite is a naturally abundant carbonate mineral possessing important links to economic mineral deposits, petroleum reservoirs and carbonate geochemistry, yet the geochemical conditions by which it forms remain a mystery. Abundant attempts to synthesis dolomite at temperatures below 100 °C have proved unsuccessful, forming the paradox known as the “dolomite problem”. This study demonstrates a newly developed method capable of synthesizing dolomite at temperatures as low as 60 °C. This method, involving the addition of solid phase Na2CO3 to Ca-Mg2+ cation solutions, seemingly overcomes the kinetic barriers known to inhibit dolomite formation by rapid replacement of Na2CO3. Furthermore, although previously proposed to encourage dolomite formation, the role of urea facilitating dolomite synthesis is confirmed. The addition of varying urea concentrations is found to improve the stoichiometry and cation ordering of dolomite between 50 - 80 °C, and notably, dolomite synthesis at 50 °C requires a 252 mmolal urea concentration in solution. These findings provide a foundational tool which will greatly benefit future research into answering the “dolomite problem”. Due to the inability to synthesize dolomite at low temperatures, understanding of isotope fractionation between dolomite and water has been poorly constrained. Therefore, calibrations of the dolomite-water oxygen isotope paleothermometer are scarce, relying on data from either the extrapolation of high temperature (> 100 °C) dolomite studies or protodolomite synthesized at more ambient temperatures. Provided here is a new dolomite-water oxygen isotope fractionation curve, constructed from dolomite synthesized between 50 - 80 °C. Although certain dolomite synthesized by the method developed in this study display apparent isotopic heterogeneity, a correction is applied to more closely resemble isotopic equilibrium fractionation between dolomite and water. Initial investigations into isotope effects associated with dolomite synthesis by the method developed here are promising and should strengthen the role of dolomite in carbonate geochemistry research.ThesisMaster of Science (MSc