413 research outputs found

    A Macro-econometric Model for Ireland

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    The Bank’s Macro-Econometric model has recently been revised. This paper outlines the context within which the model was initially built and the reasons for the revision and re-estimation. Compilation of the data used was a key component of the revision and this is described. The general structure of the model is outlined. Key equations are described and estimation issues noted. A discussion on simulating the model is provided along with results from sample simulations. The paper concludes with a discussion of how future work on the model might evolve.

    Sum of squares lower bounds for refuting any CSP

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    Let P:{0,1}k→{0,1}P:\{0,1\}^k \to \{0,1\} be a nontrivial kk-ary predicate. Consider a random instance of the constraint satisfaction problem CSP(P)\mathrm{CSP}(P) on nn variables with Δn\Delta n constraints, each being PP applied to kk randomly chosen literals. Provided the constraint density satisfies Δ≫1\Delta \gg 1, such an instance is unsatisfiable with high probability. The \emph{refutation} problem is to efficiently find a proof of unsatisfiability. We show that whenever the predicate PP supports a tt-\emph{wise uniform} probability distribution on its satisfying assignments, the sum of squares (SOS) algorithm of degree d=Θ(nΔ2/(t−1)log⁡Δ)d = \Theta(\frac{n}{\Delta^{2/(t-1)} \log \Delta}) (which runs in time nO(d)n^{O(d)}) \emph{cannot} refute a random instance of CSP(P)\mathrm{CSP}(P). In particular, the polynomial-time SOS algorithm requires Ω~(n(t+1)/2)\widetilde{\Omega}(n^{(t+1)/2}) constraints to refute random instances of CSP(P)(P) when PP supports a tt-wise uniform distribution on its satisfying assignments. Together with recent work of Lee et al. [LRS15], our result also implies that \emph{any} polynomial-size semidefinite programming relaxation for refutation requires at least Ω~(n(t+1)/2)\widetilde{\Omega}(n^{(t+1)/2}) constraints. Our results (which also extend with no change to CSPs over larger alphabets) subsume all previously known lower bounds for semialgebraic refutation of random CSPs. For every constraint predicate~PP, they give a three-way hardness tradeoff between the density of constraints, the SOS degree (hence running time), and the strength of the refutation. By recent algorithmic results of Allen et al. [AOW15] and Raghavendra et al. [RRS16], this full three-way tradeoff is \emph{tight}, up to lower-order factors.Comment: 39 pages, 1 figur

    Candida albicans biofilm heterogeneity does not influence denture stomatitis but strongly influences denture cleansing capacity

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    Approximately 20  % of the UK population wear some form of denture prosthesis, resulting in denture stomatitis in half of these individuals. Candida albicans is primarily attributed as the causative agent, due to its biofilm -forming ability. Recently, there has been increasing evidence of C. albicans biofilm heterogeneity and the negative impact it can have clinically; however, this phenomenon has yet to be studied in relation to denture isolates. The aims of this study were to evaluate C. albicans biofilm formation of clinical denture isolates in a denture environment and to assess antimicrobial activity of common denture cleansers against these tenacious communities. C. albicans isolated from dentures of healthy and diseased individuals was quantified using real-time PCR and biofilm biomass assessed using crystal violet. Biofilm development on the denture substratum poly(methyl methacrylate), Molloplast B and Ufi-gel was determined. Biofilm formation was assessed using metabolic and biomass stains, following treatment with denture hygiene products. Although C. albicans was detected in greater quantities in diseased individuals, it was not associated with increased biofilm biomass. Denture substrata were shown to influence biofilm biomass, with poly(methyl methacrylate) providing the most suitable environment for C. albicans to reside. Of all denture hygiene products tested, Milton had the most effective antimicrobial activity, reducing biofilm biomass and viability the greatest. Overall, our results highlight the complex nature of denture- related disease, and disease development cannot always be attributed to a sole cause. It is the distinct combination of various factors that ultimately determines the pathogenic outcome

    Career development learning in the curriculum: What is an academic’s role?

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    Career development learning (CDL) is an approach to developing student employability that enables students to reflect on and plan their future careers through engaging in activities outside or within their degree. Building on literature arguing for the benefits of integrating CDL within curriculum, this study examines academics’ perceived roles facilitating CDL. Informed by the principles and processes of Interpretive Phenomenological Analysis (IPA), 55 academics were interviewed from one institution, enabling responses to be examined through a common lens of teaching, policy and governance structures. Findings demonstrate that while some participants broadly understood the value of CDL, the term CDL is not well known. Further, while CDL strategies within teaching contexts occur, they are mostly unplanned or dialogic. This paper presents a taxonomy of current practice, featuring 11 diverse roles for facilitating CDL within curriculum grouped as absent, implicit and explicit approaches. The paper offers recommendations for a university-wide agenda for employability that features CDL strategies embedded across core curricula

    Is Mitigation Translocation an Effective Strategy for Conserving Common Chuckwallas?

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    Mitigation translocation remains a popular conservation tool despite ongoing debate regarding its utility for population conservation. To add to the understanding of the effectiveness of mitigation translocation, in 2017 and 2018 we monitored a population of protected common chuckwallas (Sauromalus ater) following translocation away from the area of construction of a new highway near the South Mountains, Phoenix, Arizona, USA. We removed chuckwallas from the construction right-of-way, paint-marked and pit-tagged them, and then released them in a nearby municipal preserve. We deployed very high frequency radio-telemetry transmitters on a sub-sample of 15 translocated adult chuckwallas. We monitored the radio-marked chuckwallas once a day at 1- to 3-day intervals for up to 46 days to document survival, body mass, and post-release movements. The average distance moved following translocation was 359 ± 53 m. Using minimum convex polygons, the average home range size of translocated lizards was 0.9 ± 0.3 ha, which was 18–45 times larger than expected for the species. Following translocations, we surveyed the translocation sites 1 month later and again 1 year later to determine the presence of translocated chuckwallas. Translocated individuals were rarely observed a second time: in 2017, only 11 of 160 translocated chuckwallas were seen again, and in 2018, only 11 of 192 translocated chuckwallas were detected. In the light of low recapture rate, consistent loss of body mass, and large movements of marked lizards, we conclude that survival of translocated chuckwallas was low over a single year. In the future, efficacy of mitigation translocation could be better evaluated by assessing the spatial ecology of both resident and translocated individuals simultaneously using radio-telemetry

    Measuring the galaxy-mass and galaxy-dust correlations through magnification and reddening

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    We present a simultaneous detection of gravitational magnification and dust reddening effects due to galactic halos and large-scale structure. The measurement is based on correlating the brightness of ~85,000 quasars at z>1 with the position of 20 million galaxies at z~0.3 derived from the Sloan Digital Sky Survey and is used to constrain the galaxy-mass and galaxy-dust correlation functions up to cosmological scales. The presence of dust is detected from 20 kpc to several Mpc, and we find its projected density to follow: Sigma_dust ~ theta^-0.8, a distribution similar to mass. The amount of dust in galactic halos is found to be comparable to that in disks. On large scales its wavelength dependence is described by R_V=3.9+/-2.6, consistent with interstellar dust. We estimate the resulting opacity of the Universe as a function of redshift and find A_V~0.03 mag up to z=0.5. This, in turn, implies a cosmic dust density of Omega_dust ~ 5x10^-6, roughly half of which comes from dust in halos of ~L* galaxies. We present magnification measurements, corrected for dust extinction, from which the galaxy-mass correlation function is inferred. The mean mass profile around galaxies is found to be Sigma ~ 30 (theta/arcmin)^-0.8 h M_sun/pc^2 up to a radius of 10 Mpc, in agreement with gravitational shear estimates.Comment: 16 pages, 10 figures, submitted to MNRA

    Putting the voices and insights of migrants and diverse ethnic groups at the centre of our response to COVID-19

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    There is increasing evidence of inequities in COVID-19 infection, disease severity, and mortality across diverse ethnic groups. Despite calls to ensure ethnicity is integral to COVID-19 research, opportunities have been missed to engage with individuals from ethnic minority groups, and even more notably, recent migrants. There is an urgent need to strengthen patient and public involvement and engagement (PPIE) and participatory research, as well as collaboration with healthcare workers from diverse migrant and ethnic backgrounds. This will require addressing multiple barriers to involvement, and a commitment to community-centred research to address the acute needs of the populations hardest hit by the pandemic

    Serum from COVID-19 patients early in the pandemic shows limited evidence of cross-neutralization against variants of concern

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) results in a variety of clinical symptoms ranging from no or mild to severe disease. Currently, there are multiple postulated mechanisms that may push a moderate to severe disease into a critical state. Human serum contains abundant evidence of the immune status following infection. Cytokines, chemokines, and antibodies can be assayed to determine the extent to which a patient responded to a pathogen. We examined serum and plasma from a cohort of patients infected with SARS-CoV-2 early in the pandemic and compared them to negative-control sera. Cytokine and chemokine concentrations varied depending on the severity of infection, and antibody responses were significantly increased in severe cases compared to mild to moderate infections. Neutralization data revealed that patients with high titers against an early 2020 SARS-CoV-2 isolate had detectable but limited neutralizing antibodies against the emerging SARS-CoV-2 Alpha, Beta and Delta variants. This study highlights the potential of re-infection for recovered COVID-19 patients
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