Mechanical response of plectonemic DNA: an analytical solution

We consider an elastic rod model for twisted DNA in the plectonemic regime. The molecule is treated as an impenetrable tube with an effective, adjustable radius. The model is solved analytically and we derive formulas for the contact pressure, twisting moment and geometrical parameters of the supercoiled region. We apply our model to magnetic tweezer experiments of a DNA molecule subjected to a tensile force and a torque, and extract mechanical and geometrical quantities from the linear part of the experimental response curve. These reconstructed values are derived in a self-contained manner, and are found to be consistent with those available in the literature.Comment: 14 pages, 4 figure

24^{24}Mg(pp, α\alpha)21^{21}Na reaction study for spectroscopy of 21^{21}Na

The $^{24}$Mg($p$, $\alpha$)$^{21}$Na reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain spins and parities of energy levels in $^{21}$Na for the astrophysically important $^{17}$F($\alpha, p$)$^{20}$Ne reaction rate calculation. 31 MeV proton beams from the 25-MV tandem accelerator and enriched $^{24}$Mg solid targets were used. Recoiling $^{4}$He particles from the $^{24}$Mg($p$, $\alpha$)$^{21}$Na reaction were detected by a highly segmented silicon detector array which measured the yields of $^{4}$He particles over a range of angles simultaneously. A new level at 6661 $\pm$ 5 keV was observed in the present work. The extracted angular distributions for the first four levels of $^{21}$Na and Distorted Wave Born Approximation (DWBA) calculations were compared to verify and extract angular momentum transfer.Comment: 11 pages, 6 figures, proceedings of the 18th International Conference on Accelerators and Beam Utilization (ICABU2014

Glucose enhancement of human memory: A comprehensive research review of the glucose memory facilitation effect

The brain relies upon glucose as its primary fuel. In recent years, a rich literature has developed from both human and animal studies indicating that increases in circulating blood glucose can facilitate cognitive functioning. This phenomenon has been termed the ‘glucose memory facilitation effect’. The purpose of this review is to discuss a number of salient studies which have investigated the influence of glucose ingestion on neurocognitive performance in individuals with (a) compromised neurocognitive capacity, as well as (b) normally functioning individuals (with a focus on research conducted with human participants). The proposed neurocognitive mechanisms purported to underlie the modulatory effect of glucose on neurocognitive performance will also be considered. Many theories have focussed upon the hippocampus, given that this brain region is heavily implicated in learning and memory. Further, it will be suggested that glucose is a possible mechanism underlying the phenomenon that enhanced memory performance is typically observed for emotionally laden stimuli

High level triggers for explosive mafic volcanism: Albano Maar, Italy

Colli Albani is a quiescent caldera complex located within the Roman Magmatic Province (RMP), Italy. The recent Via dei Laghi phreatomagmatic eruptions led to the formation of nested maars. Albano Maar is the largest and has erupted seven times between ca 69-33ka. The highly explosive nature of the Albano Maar eruptions is at odds with the predominant relatively mafic (SiO2=48-52wt.%) foiditic (K2O=9wt.%) composition of the magma. The deposits have been previously interpreted as phreatomagmatic, however they contain large amounts (up to 30%vol) of deep seated xenoliths, skarns and all pre-volcanic subsurface units. All of the xenoliths have been excavated from depths of up to 6km, rather than being limited to the depth at which magma and water interaction is likely to have occurred, suggesting an alternative trigger for eruption. High precision geochemical glass and mineral data of fresh juvenile (magmatic) clasts from the small volume explosive deposits indicate that the magmas have evolved along one of two evolutionary paths towards foidite or phonolite. The foiditic melts record ca. 50% mixing between the most primitive magma and Ca-rich melt, late stage prior to eruption. A major result of our study is finding that the generation of Ca-rich melts via assimilation of limestone, may provide storage for significant amounts of CO2 that can be released during a mixing event with silicate magma. Differences in melt evolution are inferred as having been controlled by variations in storage conditions: residence time and magma volume. © 2013

A multi-centre cohort study evaluating the role of Inflammatory Markers In patient’s presenting with acute ureteric Colic (MIMIC)

BACKGROUND: Spontaneous Stone Passage (SSP) rates in acute ureteric colic range from 47–75%. There is conflicting evidence on the role of raised inflammatory markers in acute ureteric colic. The use of an easily applicable biomarker that could predict SSP or need for intervention would improve the management of obstructing ureteric stones. Thus, there is a need to determine in an appropriately powered study, in patients who are initially managed conservatively, which factors at the time of acute admission can predict subsequent patient outcome such as SSP and the need for intervention. Particularly, establishing whether levels of white cell count (WBC) at presentation are associated with likelihood of SSP or intervention may guide clinicians on the management of these patients’ stones. DESIGN: Multi-center cohort study disseminated via the UK British Urology Researchers in Surgical Training (BURST) and Australian Young Urology Researchers Organisation (YURO). PRIMARY RESEARCH QUESTION: What is the association between WBC and SSP in patients discharged from emergency department after initial conservative management? PATIENT POPULATION: Patients who have presented with acute renal colic with CT KUB evidence of a solitary ureteric stone. A minimum sample size of 720 patients across 15 centres will be needed. HYPOTHESIS: A raised WBC is associated with decreased odds of spontaneous stone passage. PRIMARY OUTCOME: The occurrence of SSP within six months of presentation with acute ureteric colic (YES/NO). SSP was defined as absence of need for intervention to assist stone passage STATISTICAL ANALYSIS PLAN: A multivariable logistic regression model will be constructed, where the outcome of interest is SSP using data from patients who do not undergo intervention at presentation. A random effect will be used to account for clustering of patients within hospitals/institutions. The model will include adjustments for gender, age as control variables

It could probably help someone else but not me : a feasibility study of a snack programme offered to meals on wheels clients

Objectives Community-based services, such as Meals on Wheels (MOW), allow older adults to remain in their homes for as long as possible. Many MOW recipients experience decreased appetite that limits intake at mealtimes. This pilot study aimed to determine the feasibility of providing high protein high energy snacks to improve nutrient intakes of MOW clients in a regional centre of New South Wales, Australia. Participants A convenience sample of 12 MOW clients. Intervention Participants received snacks five times a week, in addition to their usual MOW order, for four weeks. Measurements Nutritional status was assessed using the Mini Nutritional Assessment tool. Pre-post changes in dietary intake were assessed using a diet history and food frequency questionnaire. Qualitative interviews conducted in clients’ homes were digitally recorded, transcribed verbatim, and themes identified. Results Post-intervention, there was a trend for an increased energy (mean = +415kJ (SD=1477)/day) and protein (+7.2 (±14.06) g/day) intake. MNA scores significantly increased (P= 0.036) and proportion of respondents categorised as ‘malnourished’ or ‘at risk of malnutrition’ decreased from 17% to 8%, and 67% to 25%, respectively (P Conclusion Provision of an additional daily mid-meal snack may be a useful addition to existing MOW services, for improved energy and protein intakes. However, not all MOW clients at risk of malnutrition perceived the snacks to be beneficial to them

Appointments, pay and performance in UK boardrooms by gender

This article uses UK data to examine issues regarding the scarcity of women in boardroom positions. The article examines appointments, pay and any associated productivity effects deriving from increased diversity. Evidence of gender-bias in the appointment of women as non-executive directors is found together with mixed evidence of discrimination in wages or fees paid. However, the article finds no support for the argument that gender diverse boards enhance corporate performance. Proposals in favour of greater board diversity may be best structured around the moral value of diversity, rather than with reference to an expectation of improved company performance

Study of galaxies in the Lynx-Cancer void. -- III. New extreme LSB dwarf galaxies

(Abridged) We present the results of the complex study of the low surface brightness dwarf (LSBD) gas-rich galaxies J0723+3621, J0737+4724 and J0852+1350, which reside in the nearby Lynx-Cancer void. Their ratios M(HI)/L_B, according to HI data obtained with the NRT, are respectively ~3.9, ~2, ~2.6. For the two latter galaxies, we derived oxygen abundance corresponding to the value of 12+log(O/H) <~7.3, using spectra from the Russian 6m telescope and from the SDSS database. We found two additional blue LSB dwarfs, J0723+3622 and J0852+1351, which appear to be physical companions of J0723+3621 and J0852+1350 situated at the projected distances of ~12--13 kpc. The companion relative velocities, derived from the BTA spectra, are dV = +89 km/s and +30 km/s respectively. The geometry and the relative orientation of orbits and spins in these pairs indicate, respectively, prograde and polar encounters for J0723+3621 and J0852+1350. The NRT HI profiles of J0723+3621 and J0723+3622 indicate a sizable gas flow in this system. The SDSS u,g,r,i images of the five dwarfs are used to derive the photometric parameters and the exponential or Sersic disc model fits. For three of them, the (u-g),(g-r),(r-i) colours of the outer parts, being compared with the PEGASE evolutionary tracks, evidence for the dominance of the old stellar populations with ages of T ~(8-10)+-3 Gyr. For J0723+3622 and J0737+4724, the outer region colours appear rather blue, implying the ages of the oldest visible stars of T <~1-3 Gyr. The new LSB galaxies complement the list of the known most metal-poor and `unevolved' dwarfs in this void, including DDO 68, SDSS J0926+3343 and others. This unique concentration of 'unevolved' dwarf galaxies in a small cell of the nearby Universe implies a physical relationship between the slow galaxy evolution and the void-type global environment.Comment: 16 pages, 5 tables, 9 figures. MNRAS, in pres

Conformational Instability of Rodlike Polyelectrolytes due to Counterion Fluctuations

The effective elasticity of highly charged stiff polyelectrolytes is studied in the presence of counterions, with and without added salt. The rigid polymer conformations may become unstable due to an effective attraction induced by counterion density fluctuations. Instabilities at the longest, or intermediate length scales may signal collapse to globule, or necklace states, respectively. In the presence of added-salt, a generalized electrostatic persistence length is obtained, which has a nontrivial dependence on the Debye screening length. It is also found that the onset of conformational instability is a re-entrant phenomenon as a function of polyelectrolyte length for the unscreened case, and the Debye length or salt concentration for the screened case. This may be relevant in understanding the experimentally observed re-entrant condensation of DNA.Comment: 8 pages, 4 figure