Kinetic approaches to particle acceleration at cosmic ray modified shocks

Kinetic approaches provide an effective description of the process of particle acceleration at shock fronts and allow to take into account the dynamical reaction of the accelerated particles as well as the amplification of the turbulent magnetic field as due to streaming instability. The latter does in turn affect the maximum achievable momentum and thereby the acceleration process itself, in a chain of causality which is typical of non-linear systems. Here we provide a technical description of two of these kinetic approaches and show that they basically lead to the same conclusions. In particular we discuss the effects of shock modification on the spectral shape of the accelerated particles, on the maximum momentum, on the thermodynamic properties of the background fluid and on the escaping and advected fluxes of accelerated particles.Comment: 22 pages, 7 figures, accepted for publication in MNRA

The X-ray Emissions from the M87 Jet: Diagnostics and Physical Interpretation

We reanalyze the deep Chandra observations of the M87 jet, first examined by Wilson & Yang (2002). By employing an analysis chain that includes image deconvolution, knots HST-1 and I are fully separated from adjacent emission. We find slight but significant variations in the spectral shape, with values of $\alpha_x$ ranging from $\sim 1.2-1.6$. We use VLA radio observations, as well as HST imaging and polarimetry data, to examine the jet's broad-band spectrum and inquire as to the nature of particle acceleration in the jet. As shown in previous papers, a simple continuous injection model for synchrotron-emitting knots, in which both the filling factor, $f_{acc}$, of regions within which particles are accelerated and the energy spectrum of the injected particles are constant, cannot account for the X-ray flux or spectrum. Instead, we propose that $f_{acc}$ is a function of position and energy and find that in the inner jet, $f_{acc} \propto E_\gamma^{-0.4 \pm 0.2} \propto E_e^{-0.2 \pm 0.1}$, and in knots A and B, $f_{acc} \propto E_\gamma^{-0.7 \pm 0.2} \propto E_e^{-0.35 \pm 0.1}$, where $E_\gamma$ is the emitted photon energy and and $E_e$ is the emitting electron energy. In this model, the index $p$ of the injected electron energy spectrum ($n(E_{e}) \propto E_{e}^{-p}$) is $p=2.2$ at all locations in the jet, as predicted by models of cosmic ray acceleration by ultrarelativistic shocks. There is a strong correlation between the peaks of X-ray emission and minima of optical percentage polarization, i.e., regions where the jet magnetic field is not ordered. We suggest that the X-ray peaks coincide with shock waves which accelerate the X-ray emitting electrons and cause changes in the direction of the magnetic field; the polarization is thus small because of beam averaging.Comment: Accepted for publication in ApJ; 21 pages, 9 figures, 2 tables; abstract shortened for astro-ph; Figures 1, 7 and 8 at reduced resolutio

Components of impactful dementia training for general hospital staff: a collective case study

Background and objectives: People with dementia occupy around one quarter of general hospital beds, with concerns consistently raised about care quality. Improving workforce knowledge, skills and attitudes is a mechanism for addressing this. However little is known about effective ways of training healthcare staff about dementia. This study aimed to understand models of dementia training most likely to lead to improved practice and better care experiences for people with dementia, and to understand barriers and facilitators to implementation. Method: A collective case study was conducted in three National Health Service Acute Hospital Trusts in England. Multiple data sources were used including interviews with training leads/facilitators, ward managers and staff who had attended training; satisfaction surveys with patients with dementia and/or carers; and observations of care using Dementia Care Mapping. Results: Interactive face-to-face training designed for general hospital staff was valued. Simulation and experiential learning methods were felt to be beneficial by some staff and stressful and distressing by others. Skilled delivery by an experienced and enthusiastic facilitator was identified as important. Staff identified learning and practice changes made following their training. However, observations revealed not all staff had the knowledge, attitudes and skills needed to deliver good care. Patient and carer satisfaction with care was mixed. A major barrier to training implementation was lack of resources. Supportive managers, organisational culture and strong leadership were key facilitators. Conclusion: Dementia training can lead to improved care practices. There are a range of key barriers and facilitators to implementation that must be considered

Understanding Urban Demand for Wild Meat in Vietnam: Implications for Conservation Actions

Vietnam is a significant consumer of wildlife, particularly wild meat, in urban restaurant settings. To meet this demand, poaching of wildlife is widespread, threatening regional and international biodiversity. Previous interventions to tackle illegal and potentially unsustainable consumption of wild meat in Vietnam have generally focused on limiting supply. While critical, they have been impeded by a lack of resources, the presence of increasingly organised criminal networks and corruption. Attention is, therefore, turning to the consumer, but a paucity of research investigating consumer demand for wild meat will impede the creation of effective consumer-centred interventions. Here we used a mixed-methods research approach comprising a hypothetical choice modelling survey and qualitative interviews to explore the drivers of wild meat consumption and consumer preferences among residents of Ho Chi Minh City, Vietnam. Our findings indicate that demand for wild meat is heterogeneous and highly context specific. Wild-sourced, rare, and expensive wild meat-types are eaten by those situated towards the top of the societal hierarchy to convey wealth and status and are commonly consumed in lucrative business contexts. Cheaper, legal and farmed substitutes for wild-sourced meats are also consumed, but typically in more casual consumption or social drinking settings. We explore the implications of our results for current conservation interventions in Vietnam that attempt to tackle illegal and potentially unsustainable trade in and consumption of wild meat and detail how our research informs future consumer-centric conservation actions

Inequalities and identity processes in crises: recommendations for facilitating safe response to the COVID-19 pandemic

Structural inequalities and identity processes are pivotal to understanding public response to COVID‐19. We discuss how identity processes can be used to promote community‐level support, safe normative behaviour, and increase compliance with guidance. However, we caution how government failure to account for structural inequalities can alienate vulnerable groups, inhibit groups from being able to follow guidance, and lead to the creation of new groups in response to illegitimate treatment. Moreover, we look ahead to the longitudinal impacts of inequalities during pandemics and advise government bodies should address identity‐based inequalities to mitigate negative relations with the public and subsequent collective protest

Nonthermal Emission from a Supernova Remnant in a Molecular Cloud

In evolved supernova remnants (SNRs) interacting with molecular clouds, such as IC 443, W44, and 3C391, a highly inhomogeneous structure consisting of a forward shock of moderate Mach number, a cooling layer, a dense radiative shell and an interior region filled with hot tenuous plasma is expected. We present a kinetic model of nonthermal electron injection, acceleration and propagation in that environment and find that these SNRs are efficient electron accelerators and sources of hard X- and gamma-ray emission. The energy spectrum of the nonthermal electrons is shaped by the joint action of first and second order Fermi acceleration in a turbulent plasma with substantial Coulomb losses. Bremsstrahlung, synchrotron, and inverse Compton radiation of the nonthermal electrons produce multiwavelength photon spectra in quantitative agreement with the radio and the hard emission observed by ASCA and EGRET from IC 443. We distinguish interclump shock wave emission from molecular clump shock wave emission accounting for a complex structure of molecular cloud. Spatially resolved X- and gamma- ray spectra from the supernova remnants IC 443, W44, and 3C391 as might be observed with BeppoSAX, Chandra XRO, XMM, INTEGRAL and GLAST would distinguish the contribution of the energetic lepton component to the gamma-rays observed by EGRET.Comment: 14 pages, 4 figure, Astrophysical Journal, v.538, 2000 (in press

Innovative placement allocation model for pre-registration student nurses

Student nurses require a variety of high quality practice placements to prepare them for registration with the Nursing and Midwifery Council (NMC) yet in reality this can be difficult to achieve. This case study reports on the development and implementation of a Practice Placement Allocation Model that has provided one University in the north west of England and its partner practice placement healthcare organisations with a framework to shift from a traditional, process-led pre-registration nursing student placement allocation system (adult field) to a robust, proactive, student-focused approach. The model is based upon practice placement allocation partnership concepts and these include advanced planning of student placements and clear lines of communication between all stakeholders involved in the practice placement of students. Application of the model has resulted in the sharing of timely information across organisations via a central framework and this has allowed for any underlying practice allocation problems to be quickly identified and resolved. Importantly, each practice partner now fully understands the role that they play and how to communicate more effectively. Challenges and opportunities are presented together with the evidence of how the model can be transferred to other healthcare professions and fields of nursing. 5 key points: 1. The government is insistent on producing and maintain a nursing workforce that provides quality and compassionate nursing care 2. The nursing students’ practice placement is a key component of an effective pre-registration nurse education programme 3. Ensuring that all nursing students have the variety of placements can be a challenge to providers of pre-registration nurse education 4. Practice placements should be mapped and allocated according to the students education programme requirements and individual needs 5. Application of a Practice Placement Allocation Model provides the best platform for the effective placement of nursing students and promotes partnership working between stakeholder

The Extremely High Energy Cosmic Rays

Experimental results from Haverah Park, Yakutsk, AGASA and Fly's Eye are reviewed. All these experiments work in the energy range above 0.1 EeV. The 'dip' structure around 3 EeV in the energy spectrum is well established by all the experiments, though the exact position differs slightly. Fly's Eye and Yakutsk results on the chemical composition indicate that the cosmic rays are getting lighter over the energy range from 0.1 EeV to 10 EeV, but the exact fraction is hadronic interaction model dependent, as indicated by the AGASA analysis. The arrival directions of cosmic rays are largely isotropic, but interesting features may be starting to emerge. Most of the experimental results can best be explained with the scenario that an extragalactic component gradually takes over a galactic population as energy increases and cosmic rays at the highest energies are dominated by particles coming from extragalactic space. However, identification of the extragalactic sources has not yet been successful because of limited statistics and the resolution of the data.Comment: The review paper including 21 figures. 39 pages: To be published in Journal of Physics