Resonant helical deformations in nonhomogeneous Kirchhoff filaments

We study the three-dimensional static configurations of nonhomogeneous Kirchhoff filaments with periodically varying Young's modulus. This type of variation may occur in long tandemly repeated sequences of DNA. We analyse the effects of the Young's modulus frequence and amplitude of oscillation in the stroboscopic maps, and in the regular (non chaotic) spatial configurations of the filaments. Our analysis shows that the tridimensional conformations of long filaments may depend critically on the Young's modulus frequence in case of resonance with other natural frequencies of the filament. As expected, far from resonance the shape of the solutions remain very close to that of the homogeneous case. In the case of biomolecules, it is well known that various other elements, besides sequence-dependent effects, combine to determine their conformation, like self-contact, salt concentration, thermal fluctuations, anisotropy and interaction with proteins. Our results show that sequence-dependent effects alone may have a significant influence on the shape of these molecules, including DNA. This could, therefore, be a possible mechanical function of the ``junk'' sequences.Comment: 18 pages (twocolumn), 5 figures Revised manuscrip

Lime stabilisation for earthworks: a UK perspective

Lime stabilisation is a versatile technique applied during earthworks operations. Modern soil recycling units are much more efficient at pulverising fill material and intermixing the added binder/water than machinery available 20 years ago. While supplier innovation adds flexibility to the site working method, specifications have not been sufficiently updated to permit optimal application. This review paper details the physico-chemical changes instigated through the lime-clay soil reaction, updating previous reviews. It aims to assist scientific debate, current practitioners and future specification changes. For example, the application of the minimum 24 h mellowing periods (mandatory to UK specifications) with high reactivity, quicklime powders is concluded to cause increased air voids in the compacted fill. Increased air voids are associated with reduced long-term strength and potential volume change from water ingress, which is of particular concern for sulfate swelling. Shorter mellowing periods and/or use of hydrated lime may lesson this issue; however, a 'one size fits all' approach is discouraged in preference to site-specific methodologies refined to suit the fill material and project requirements. The discussion also summarises working methods which may lower the risk of sulfate swell and defines areas requiring further practical research

D-brane potentials in the warped resolved conifold and natural inflation

In this paper we obtain a model of Natural Inflation from string theory with a Planckian decay constant. We investigate D-brane dynamics in the background of the warped resolved conifold (WRC) throat approximation of Type IIB string compactifications on Calabi-Yau manifolds. When we glue the throat to a compact bulk Calabi-Yau, we generate a D-brane potential which is a solution to the Laplace equation on the resolved conifold. We can exactly solve this equation, including dependence on the angular coordinates. The solutions are valid down to the tip of the resolved conifold, which is not the case for the more commonly used deformed conifold. This allows us to exploit the effect of the warping, which is strongest at the tip. We inflate near the tip using an angular coordinate of a D5-brane in the WRC which has a discrete shift symmetry, and feels a cosine potential, giving us a model of Natural Inflation, from which it is possible to get a Planckian decay constant whilst maintaining control over the backreaction. This is because the decay constant for a wrapped brane contains powers of the warp factor, and so can be made large, while the wrapping parameter can be kept small enough so that backreaction is under control.Comment: 41 pages, 3 appendices, 1 figure, PDFLaTex; various clarifications added along with a new appendix on b-axions and wrapped D5 branes;version matches the one published in JHE

Healing Right Way: study protocol for a stepped wedge cluster randomised controlled trial to enhance rehabilitation services and improve quality of life in Aboriginal Australians after brain injury.

IntroductionDespite higher incidence of brain injury among Aboriginal compared with non-Aboriginal Australians, suboptimal engagement exists between rehabilitation services and Aboriginal brain injury survivors. Aboriginal patients often feel culturally insecure in hospital and navigation of services post discharge is complex. Health professionals report feeling ill-equipped working with Aboriginal patients. This study will test the impact of a research-informed culturally secure intervention model for Aboriginal people with brain injury. METHODS AND ANALYSIS: Design: Stepped wedge cluster randomised control trial design; intervention sequentially introduced at four pairs of healthcare sites across Western Australia at 26-week intervals.Recruitment: Aboriginal participants aged ≥18 years within 4 weeks of an acute stroke or traumatic brain injury.Intervention: (1) Cultural security training for hospital staff and (2) local, trial-specific, Aboriginal Brain Injury Coordinators supporting participants.Primary outcome: Quality-of-life using EuroQOL-5D-3L (European Quality of Life scale, five dimensions, three severity levels) Visual Analogue Scale score at 26 weeks post injury. Recruitment of 312 participants is estimated to detect a difference of 15 points with 80% power at the 5% significance level. A linear mixed model will be used to assess the between-condition difference.Secondary outcome measures: Modified Rankin Scale, Functional Independence Measure, Modified Caregiver Strain Index, Hospital Anxiety and Depression Scale at 12 and 26 weeks post injury, rehabilitation occasions of service received, hospital compliance with minimum care processes by 26 weeks post injury, acceptability of Intervention Package, feasibility of Aboriginal Brain Injury Coordinator role.Evaluations: An economic evaluation will determine the potential cost-effectiveness of the intervention. Process evaluation will document fidelity to study processes and capture changing contexts including barriers to intervention implementation and acceptability/feasibility of the intervention through participant questionnaires at 12 and 26 weeks.Ethics and disseminationThe study has approvals from Aboriginal, university and health services human research ethics committees. Findings will be disseminated through stakeholder reports, participant workshops, peer-reviewed journal articles and conference papers.Trial registration numberACTRN12618000139279

An interlaboratory investigation of intrinsic dissolution rate determination using surface dissolution

The pur­pose of this study was to con­duct an in­ter­lab­o­ra­tory ring-study, with six part­ners (aca­d­e­mic and in­dus­trial), in­ves­ti­gat­ing the mea­sure­ment of in­trin­sic dis­so­lu­tion rate (IDR) us­ing sur­face dis­so­lu­tion imag­ing (SDI) equip­ment. Mea­sure­ment of IDR is im­por­tant in phar­ma­ceu­ti­cal re­search as it pro­vides char­ac­ter­is­ing in­for­ma­tion on drugs and their for­mu­la­tions. This work al­lowed us to as­sess the SDI’s in­ter­lab­o­ra­tory per­for­mance for mea­sur­ing IDR us­ing a de­fined stan­dard op­er­at­ing pro­ce­dure (see sup­port­ing in­for­ma­tion) and six drugs as­signed as low (tadalafil, bromocrip­tine me­sy­late), medium (carvedilol, in­domethacin) and high (ibupro­fen, val­sar­tan) sol­u­bil­ity com­pounds. Fasted State Sim­u­lated In­testi­nal Fluid (FaS­SIF) and blank FaS­SIF (with­out sodium tau­ro­cholate and lecithin) (pH 6.5) were used as me­dia. Us­ing the stan­dard­ised pro­to­col an IDR value was ob­tained for all com­pounds and the re­sults show that the over­all IDR rank or­der matched the sol­u­bil­ity rank or­der. In­ter­lab­o­ra­tory vari­abil­ity was also ex­am­ined and it was ob­served that the vari­abil­ity for lower sol­u­bil­ity com­pounds was higher, co­ef­fi­cient of vari­a­tion >50%, than for in­ter­me­di­ate and high sol­u­bil­ity com­pounds, with the ex­cep­tion of in­domethacin in FaS­SIF medium. In­ter lab­o­ra­tory vari­abil­ity is a use­ful de­scrip­tor for un­der­stand­ing the ro­bust­ness of the pro­to­col and the sys­tem vari­abil­ity. On com­par­i­son to an­other pub­lished small-scale IDR study the rank or­der­ing with re­spect to dis­so­lu­tion rate is iden­ti­cal ex­cept for the high sol­u­bil­ity com­pounds. This re­sults in­di­cates that the SDI ro­bustly mea­sures IDR how­ever, no rec­om­men­da­tion on the use of one small scale method over the other is made

Increased Nucleotide Diversity with Transient Y Linkage in Drosophila americana

Recombination shapes nucleotide variation within genomes. Patterns are thought to arise from the local recombination landscape, influencing the degree to which neutral variation experiences hitchhiking with selected variation. This study examines DNA polymorphism along Chromosome 4 (element B) of Drosophila americana to identify effects of hitchhiking arising as a consequence of Y-linked transmission. A centromeric fusion between the X and 4(th) chromosomes segregates in natural populations of D. americana. Frequency of the X-4 fusion exhibits a strong positive correlation with latitude, which has explicit consequences for unfused 4(th) chromosomes. Unfused Chromosome 4 exists as a non-recombining Y chromosome or as an autosome proportional to the frequency of the X-4 fusion. Furthermore, Y linkage along the unfused 4 is disrupted as a function of the rate of recombination with the centromere. Inter-population and intra-chromosomal patterns of nucleotide diversity were assayed using six regions distributed along unfused 4(th) chromosomes derived from populations with different frequencies of the X-4 fusion. No difference in overall level of nucleotide diversity was detected among populations, yet variation along the chromosome exhibits a distinct pattern in relation to the X-4 fusion. Sequence diversity is inflated at loci experiencing the strongest Y linkage. These findings are inconsistent with the expected reduction in nucleotide diversity resulting from hitchhiking due to background selection or selective sweeps. In contrast, excessive polymorphism is accruing in association with transient Y linkage, and furthermore, hitchhiking with sexually antagonistic alleles is potentially responsible

How managers can build trust in strategic alliances: a meta-analysis on the central trust-building mechanisms

Trust is an important driver of superior alliance performance. Alliance managers are influential in this regard because trust requires active involvement, commitment and the dedicated support of the key actors involved in the strategic alliance. Despite the importance of trust for explaining alliance performance, little effort has been made to systematically investigate the mechanisms that managers can use to purposefully create trust in strategic alliances. We use Parkhe’s (1998b) theoretical framework to derive nine hypotheses that distinguish between process-based, characteristic-based and institutional-based trust-building mechanisms. Our meta-analysis of 64 empirical studies shows that trust is strongly related to alliance performance. Process-based mechanisms are more important for building trust than characteristic- and institutional-based mechanisms. The effects of prior ties and asset specificity are not as strong as expected and the impact of safeguards on trust is not well understood. Overall, theoretical trust research has outpaced empirical research by far and promising opportunities for future empirical research exist

Managing contested spaces: Public managers, obscured mechanisms and the legacy of the past in Northern Ireland

Societies emerging from ethno-political and inter-communal conflict face a range of complex problems that stem directly from the recent lived experience of bloodshed and injury, militarisation, securitisation and segregation. As institutional agents in such an environment, public managers perform the dual role of both interpreting public policy and implementing it within a politically contested space and place. In this article we address how managers cope with the outworking of ethno-nationalist conflict and peace building within government processes and policy implementation and contend this is a subject of emerging concern within the wider public administration, urban studies and conflict literature. Using data from a witness seminar initiative on the Northern Ireland conflict transformation experience, we explain how public sector managers make sense of their role in post-agreement public management and highlight the importance of three identified mechanisms; ‘bricolage’, ‘diffusion’ and ‘translation’ in the management of public sector organisations and urban spaces in a context of entrenched conflict and an uncertain path to peace