1,246 research outputs found
Experimental influence of pH on the early life-stages of sea urchins I: different rates of introduction give rise to different responses
Many early life-stage response studies to ocean acidification utilize gametes/offspring obtained from ambient-sourced parents, which are then directly introduced to experimentally altered seawater pH. This approach may produce a stress response potentially impacting development and survival. Hence, this study determined whether this approach is suitable by subjecting embryos/larvae to different rates of introduction to lowered seawater pH to assess larval success under acute and staggered experimental pH scenarios. Embryos and 4-armed larvae of the sea urchin Psammechinus miliaris were introduced to pH conditions, widely used in ocean acidification studies, from ambient conditions utilizing 380, 470, 560, 700 and 840 ppm CO2 changed at incremental steps at two rates: fast (every 3rd hour) or slow (every 48th hour). Direct transfers from ambient to low seawater pH gave rise to dramatic negative impacts (smaller size and low survival), but slower rates of introductions gave rise to lesser negative responses (low survival). There was no treatment effect on settled juveniles. Fast introductions utilized in many studies are likely not ideal approaches when assessing pre-settlement larval developmental responses. Therefore, careful consideration of the pattern of response is needed when studies report the responses of offspring, derived from ambient conditions, introduced directly to forecasted ocean acidification conditions
Strategic toolkits: seniority, usage and performance in the German SME machinery and equipment sector
This paper examines the strategic tool kit, from a human resource management (HRM) perspective, in terms of usage and impact. Research to date has tended to consider usage, assuming to a certain extent that knowledge and understanding of particular tools suggest that practitioners value them. The research on which this paper is based builds upon the idea that usage indicates satisfaction, but develops the usage theme to investigate which decision-makers are actually engaged in both tool appliance and the strategic process. Of particular interest to the researchers are the educational background, age and seniority of the decision-makers. In addition, potential links with HRM and organizational performance are also explored. The context of the research, the German machinery and equipment sector, provides an insight into the industry's ability to sustain growth in face of increasing international competition. The paper calls for a greater awareness, from a human resource perspective, and utilization of strategic management practice and associated decision-making aids
Do children get dry socket?—The incidence and pattern of presentation of alveolar osteitis in children and adolescents following dental extractions
Background
Alveolar osteitis (AO) is widely reported as the most common post-operative complication following surgical and non-surgical exodontia. Despite being one of the most studied complications in dentistry, there is no established consensus on its aetiology, alongside a relative paucity of studies looking exclusively into AO incidence in children and adolescents.
Objectives
To determine the incidence, risk factors and pattern of presentation of AO in children and adolescents following exodontia, as well as identifying concepts and theories to provide a basis regarding why such a common post-operative complication reportedly manifests so rarely in the paediatric population.
Methods
This cross-sectional analysis forms part of a prospective service evaluation of the exodontia service provided by Newcastle Dental Hospital. All patients aged 5–16 who underwent dental extractions of deciduous and/or permanent teeth under general anaesthetic (GA) between 15 June 2020 and the 15 July 2020 were telephoned 1 week following their procedure to determine if any had developed post-operative complications. Data were cleaned manually and analysed using descriptive statistics, exploratory analysis with chi-squared tests and multivariable analyses. A scoping review was performed using the PubMed, OVID Medline and Scopus databases.
Results
Four of 150 patients (2.8%) developed AO and reported extreme pain which began 2–3 days after removal, lasted 2 days after onset, and were all associated with the non-surgical removal of lower first permanent molar teeth. All patients who developed AO were female and aged between 9 and 10 years old. Mandibular sockets were significantly associated with development of AO (p = 0.026).
Conclusions
Despite the belief that AO rarely manifests in children, the incidence of paediatric AO in this study is in line with that of AO found in the adult literature. The literature is inconsistent and conflicting regarding current understanding of AO. As far as possible, an atraumatic approach to exodontia should be adopted. We have proposed four underlying concepts which may benefit from future research given the paucity of research exclusively into dry socket in children and adolescents
Quasiparticles and c-axis coherent hopping in high T_c superconductors
We study the problem of the low-energy quasiparticle spectrum of the extended
t-J model and analyze the coherent hopping between weakly coupled planes
described by this model. Starting with a two-band model describing the Cu-O
planes and the unoccupied bands associated to the metallic atoms located in
between the planes, we obtain effective hopping matrix elements describing the
c-axis charge transfer. A computational study of these processes shows an
anomalously large charge anisotropy for doping concentrations around and below
the optimal doping.Comment: 4 pages, 3 figure
Dielectronic Recombination in He+ Ions
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Dielectronic Recombination in He+ Ions
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Hot Spots and Transition from d-Wave to Another Pairing Symmetry in the Electron-Doped Cuprate Superconductors
We present a simple theoretical explanation for a transition from d-wave to
another superconducting pairing observed in the electron-doped cuprates. The
d_{x^2-y^2} pairing potential Delta, which has the maximal magnitude and
opposite signs at the hot spots on the Fermi surface, becomes suppressed with
the increase of electron doping, because the hot spots approach the Brillouin
zone diagonals, where Delta vanishes. Then, the d_{x^2-y^2} pairing is replaced
by either singlet s-wave or triplet p-wave pairing. We argue in favor of the
latter and discuss experiments to uncover it.Comment: 6 pages, 4 figures, RevTeX 4. V.2: Extra figure and many references
added. V.3: Minor update of references for the proof
Bessel Process and Conformal Quantum Mechanics
Different aspects of the connection between the Bessel process and the
conformal quantum mechanics (CQM) are discussed. The meaning of the possible
generalizations of both models is investigated with respect to the other model,
including self adjoint extension of the CQM. Some other generalizations such as
the Bessel process in the wide sense and radial Ornstein- Uhlenbeck process are
discussed with respect to the underlying conformal group structure.Comment: 28 Page
Motivational engagement in first-time hearing aid users: a feasibility study
Objective: To assess (1) the feasibility of incorporating the Ida Institute’s Motivation Tools into a UK audiology service, (2) the potential benefits of motivational engagement in first-time hearing aid users, and (3) predictors of hearing aid and general health outcome measures.
Design: A feasibility study using a single-centre, prospective, quasi-randomized controlled design with two arms. The Ida Institute’s Motivation Tools formed the basis for motivational engagement. Study sample: First-time hearing aid users were recruited at the initial hearing assessment appointment. The intervention arm underwent motivational engagement (M+, n = 32), and a control arm (M-, n = 36) received standard care only. Results: The M+ group showed greater self-efficacy, reduced anxiety, and greater engagement with the audiologist at assessment and fitting appointments. However, there were no significant between-group differences 10-weeks post-fitting. Hearing-related communication scores predicted anxiety, and social isolation scores predicted depression for the M+ group. Readiness to address hearing difficulties predicted hearing aid outcomes for the M- group. Hearing sensitivity was not a predictor of outcomes. Conclusions: There were some positive results from motivational engagement early in the patient journey. Future research should consider using qualitative methods to explore whether there are longer-term benefits of motivational engagement in hearing aid users
Extragalactic neutrino background from very young pulsars surrounded by supernova envelopes
We estimate the extragalactic muon neutrino background which is produced by
hadrons injected by very young pulsars at an early phase after supernova
explosion. It is assumed that hadrons are accelerated in the pulsar wind zone
which is filled with thermal photons captured below the expanding supernova
envelope. In collisions with those thermal photons hadrons produce pions which
decay into muon neutrinos. At a later time, muon neutrinos are also produced by
the hadrons in collisions with matter of the expanding envelope. We show that
extragalactic neutrino background predicted by such a model should be
detectable by the planned 1 km neutrino detector if a significant part of
pulsars is born with periods shorter than ms. Since such population
of pulsars is postulated by the recent models of production of extremely high
energy cosmic rays, detection of neutrinos with predicted fluxes can be used as
their observational test.Comment: 4 pages, 2 figures, A&A style, accepted to A&A Let
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