bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling glacier extents and equilibrium line altitudes in the Rwenzori Mountains, Uganda, over the last 31,000 yr
Authors: Doughty* Alice M. , Kelly Meredith A. , Russell James M. , Jackson Margaret S. , Anderson Brian M. , Chipman Jonathan , Nakileza Bob , Dee Sylvia G.
Published: September 2020

Mountain glacier moraine sequences and their chronologies allow us to evaluate the timing and climate conditions that underpin changes in the equilibrium line altitudes (ELAs), which can provide valuable information on the paleoclimatology of understudied regions such as tropical East Africa. However, moraine sequences are inherently discontinuous, and the precise climate conditions that they represent can be ambiguous due to the sensitivity of mountain glaciers to temperature, precipitation, and other environmental variables. Here, we used a two-dimensional (2-D) ice-flow and mass-balance model to simulate glacier extents and ELAs in the Rwenzori Mountains in East Africa over the past 31,000 yr (31 k.y.), including the Last Glacial Maximum (LGM), late glacial period, and the Holocene Epoch. We drove the glacier model with two independent, continuous temperature reconstructions to simulate possible glacier length changes through time. Model input paleoclimate values came from branched glycerol dialkyl glycerol tetraether (brGDGT) temperature reconstructions from alpine lakes on Mount Kenya for the last ~31 k.y., and precipitation reconstructions for the LGM came from various East African locations. We then compared the simulated fluctuations with the positions and ages (where known) of the Rwenzori moraines. The simulated glacier extents reached within 1.1 km of the dated LGM moraines in one valley (93% of the full LGM extent) when forced by the brGDGT temperature reconstructions (maximum cooling of 6.1 °C) and a decrease in precipitation (−10% than modern amounts). These simulations suggest that the Rwenzori glaciers required a cooling of at least 6.1 °C to reach the dated LGM moraines. Based on the model output, we predict an age of 12–11 ka for moraines located halfway between the LGM and modern glacier extents. We also predict ice-free conditions in the Rwenzori Mountains for most of the early to middle Holocene, followed by a late Holocene glacier readvance within the last 2000 yr.
BCG skin reactions by 2 months of age are associated with better survival in infancy: a prospective observational study from Guinea-Bissau
Authors: Schaltz-Buchholzer Frederik , Berendsen Mike , Roth Adam , Jensen Kristoffer Jarlov , Bjerregaard-Andersen Morten , Kjær Sørensen Marcus , Monteiro Ivan , Aaby Peter , Stabell Benn Christine
Published: September 2020

Introduction

Receiving Bacille Calmette-Guérin (BCG)-Denmark vaccine at birth has been associated with ~40% reductions in all-cause neonatal mortality. We evaluated determinants of BCG skin reaction characteristics by age 2 months and tested the association with subsequent mortality.

Methods

Prospective observational study amalgamating five trials providing BCG-at-birth that were conducted between 2002 and 2018 in Guinea-Bissau. The reaction status and size were evaluated at home-visits by 2 months of age among 6012 neonates; mortality from 2 to 12 months was assessed at subsequent visits. Reaction determinants were evaluated by binomial regression providing risk ratios (RRs). In Cox-models providing adjusted mortality rate ratios (aMRRs), we assessed the association between (1) having a 2-month reaction (yes/no) and (2) reaction size tertiles and subsequent all-cause mortality risk. A subgroup had their BCG reaction evaluated and were bled at age 4 weeks; their samples underwent in vitro analysis for specific and non-specific cytokine responses.

Results

The BCG strain was the main determinant for developing a 2-month reaction and the reaction size: the BCG-Russia/BCG-Denmark RR for large-reaction was 0.38 (0.30–0.47) and the BCG-Russia/BCG-Japan RR was 0.61 (0.51–0.72). 5804 infants (96.5%) were reactors by age 2 months; 208 (3.5%) were non-reactors. The 2–12 months mortality risk was 4.8% (10/208) for non-reactors, 2.9% (64/2213) for small reactors, 1.8% (30/1710) for medium reactors and 0.8% (15/1881) for large reactors. The reactor/non-reactor aMRR was 0.49 (0.26–0.95) and there was a linear trend of decreasing mortality with increasing reaction size (p for trend <0.001). BCG reactors had higher 4-week specific and non-specific cytokine responses, responses that were highest among those with large reactions.

Conclusion

Among BCG-vaccinated infants, having a BCG skin reaction by age 2 months was associated with markedly better survival, as was the reaction size. Our findings thus support that BCG has substantial effects on all-cause mortality. Emphasising at-birth vaccination with immunogenic BCG strains and revaccinating non-reactors and small reactors could have major public health benefits.

Trial registration numbers

NCT00146302,NCT00168610,NCT00625482,NCT01989026andNCT02447536.
PP11  Defining major trauma in the hyper acute setting
Authors: Thompson Lee , Hill Michael , McMeekin Peter , Shaw Gary
Published: September 2020

Background

Pre-hospital trauma is complex and challenging, with limited clinical exposure for clinicians. In addition, there is no standardised definition for major trauma, and retrospective scores commonly quantify injury severity, such as the injury severity score. This qualitative study aimed to explore the pre-hospital perspectives of major trauma and how pre-hospital trauma care providers define major trauma.

Method

Three focus groups of 40–60 minutes duration were conducted with paramedics, ambulance technicians, police, firefighters and emergency dispatchers. Digital recordings were transcribed verbatim, coded and reviewed to identify emerging themes. Constant comparison was undertaken throughout and codes identified for qualitative thematic analysis.

Results

Three overarching themes emerged: clinician factors, patient factors and situational factors. Clinician factors highlighted issues of experience and exposure (or lack of) to major trauma and its relationship to clinical concern, communication issues and the complex nature of pre-hospital trauma. Patient factors identified deranged physiology, actual injuries, life changing trauma, potential need for surgical intervention and rehabilitation as defining major trauma. These variables are often complicated by the extremities of age as well as previous medical history and medications. The situational factors identified that every traumatic encounter is unique, requiring bespoke management where high and low energy mechanisms of injury should be considered.

Conclusion

Based on the analysis of the focus groups, a working pre-hospital definition is: Any injury (or injuries) that have the potential to be life-threatening or life-changing, including those sustained from low energy mechanisms in people rendered vulnerable by extremes of age, comorbidities or frailty, resulting in significant physiological compromise (haemodynamic instability, reduced consciousness, respiratory compromise) and/or significant anatomical abnormality that may require immediate intervention.
PP12  A survey-based evaluation of the impact of menopause transition on female ambulance staff in one UK ambulance service
Authors: Foster Theresa , Prothero Larissa S , Winterson Debra
Published: September 2020

Background

Menopausal symptoms can have a significant impact on workplace attendance and performance, yet limited evidence regarding the menopause transition in the emergency services exists. The aim of this study was to explore work and personal impacts of the menopause on female staff in the ambulance setting.

Methods

A purpose-designed, online 20-question survey, based on the British Menopause Society Survey (2016), was developed to understand menopausal symptoms and their impact on female staff in one UK ambulance service. Disseminated during July 2019, it resulted in a convenience sample of 522 responses (22% of female workforce), which were analysed using quantitative (descriptive) and qualitative (thematic) approaches.

Results

Typically, respondents were either pre-menopausal (33%; n=171) or peri-menopausal (24%; n=126). Approximately one third (31%; n=161) were menopausal or post-menopausal. Over half worked in operational emergency service delivery (58%; n=301), and typically worked shifts/unsocial hours (75%; n=391). For those who had experienced menopause symptoms (64%; n=336), wide-ranging symptoms were reported: tiredness/low energy levels, difficulty sleeping/insomnia, mood changes (including anxiety and depression), musculoskeletal problems, and hot flushes and/or night sweats were most common. The majority (61%; n=205) stated they had not expected the symptoms they experienced, which had impacted on their well-being (51%; n=171); work life (45%; n=151), some requiring time off work (21%; n=71); and home life (44%; n=148). Only 12% (n=40) of respondents felt supported at work. Of most concern to respondents was lack of awareness of menopause symptoms, and their impact throughout the service, in particular those in managerial roles and male staff.

Conclusions

All women will experience the menopause and will work through and beyond this life phase. For those who experience menopausal symptoms, the impact can be significant. Yet menopause awareness in the ambulance service is limited and there is clear scope for initiatives for improved staff support and well-being.
03  What factors affect paramedics’ involvement of people with dementia in decisions affecting their care? A qualitative study
Authors: Choonara Esme
Published: September 2020

Background

Paramedics are frequently called to people with dementia due to high rates of co-morbidities and complex needs, but decision making can be challenging due to lack of information or difficulties in assessment. Best-practice dementia care should be holistic and involve people with dementia in decisions as far as possible. A small number of qualitative studies have looked at paramedics’ decision-making in relation to dementia, but these studies have not specifically investigated the involvement of people with dementia in decisions. This study aimed to explore how paramedics make decisions when attending people with dementia, with a particular focus on understanding the factors that impact on whether, how, and to what degree paramedics involve people with dementia in decisions about their care.

Methods

A generic qualitative research approach was used, informed by social constructivism and by the researcher’s commitment to the concept of ‘personhood’ in dementia care. Data were collected through semi-structured individual interviews with seven paramedics, each lasting between 40 and 80 minutes. The interviews were recorded and transcribed verbatim and subsequently analysed using thematic analysis.

Results

Four themes were identified that all touched on challenges to delivering person-centred care for people with dementia. Themes identified were: 1. Paramedics’ differing approaches to assessing capacity and making best interest decisions. 2. Communication and developing a rapport. 3. Interconnections with others important to the person with dementia. 4. The impact of paramedics’ values and attitudes.

Conclusion

The involvement of people with dementia is sometimes limited by medical, social or clinician-dependent factors. This study highlights how paramedics’ values and communication skills influence their interactions with people with dementia. As the paramedic role evolves, there is an opportunity to embed person-centred care in practice and to ensure that education equips paramedics with the skills and ethical frameworks needed to deliver high quality dementia care.
PP31  Ambulance handover: a thematic review of delays in 2018/19
Authors: Lindridge Jaqualine , Reynard Kevin , Kemp Rob , Brownhill Richard , Penn-Ashman Jerry
Published: September 2020

Background

Ambulance handover delays are an important indicator of an emergency care system under pressure. Delayed handovers compromise patient safety in the Emergency Department (ED). As a direct consequence patients wait longer for an emergency ambulance response, and as a result patient safety in the community is also compromised. We explored factors perceived to contribute to ambulance handover delays at EDs in an urban area of England, in order to inform delay reduction strategies.

Methods

Fifteen EDs were visited as part of a regional improvement programme. Ambulance handover processes were observed, and staff involved in the process were informally interviewed. A data corpus of twenty-nine written reports was generated. These reports were anonymised and thematic analysis was used inductively to explore the phenomenon of ambulance handover delay. Pattern coding was used to identify and cluster common themes, with magnitude coding added to identify the most prevalent themes.

Results

Perceived reasons for ambulance handover delay arose from a number of factors. A mismatch was frequently seen between handover capacity and demand. This occurred alongside, but was also frequently observed to be independent of, ED exit block. Approaches to escalation were often sub-optimal. This was observed both before and after an ambulance queue developed. Processes were often uneconomical by design, and pathways were frequently inefficient. Inter-professional culture was identified as an important, cross-cutting theme, with a lack of urgency to release ambulances frequently observed.

Conclusions

Our results suggest several factors influence ambulance handover delays. Programmes which aim to improve overall hospital flow, streamline pathways and processes, and improve escalation are needed. Programmes should also seek to improve the inter-professional culture relating to ambulance handover. Limitations to this enquiry include an opportunistic, retrospective approach and use of a convenience sample. There are few empirical studies which address the causes of ambulance handover delay. More research is needed on this important patient safety issue.
PP34  Collecting experience-based expertise when planning prehospital care research: a stakeholder event about evaluating paramedics working in care homes
Authors: Evans Bridie , Kingston Mark , Porter Alison , Keen Leigh , Griffiths Lesley , James Mari , Green Stephanie
Published: September 2020

Background

Due to medical advances, the population of care homes is becoming increasingly frail, often with co-morbidities. Recent innovations have seen paramedics take on non-emergency roles within or supporting care homes. This workforce innovation requires urgent evaluation, taking account of the multiple perspectives at stake. Research is more relevant, feasible and accountable if those who commission, deliver and use healthcare services are able to input their professional and personal insights.

Method

We conducted a stakeholder event as part of research development work for paramedics working in care homes (PERCH: Preliminary Exploration of paramedic Roles in Care Homes). We invited representatives from care homes, including Enabling Research in Care Homes (ENRICH) network members, ambulance services, primary and secondary care, patient/resident and public members, and the research community. To inform discussion, we presented examples of paramedics working in care homes. We then facilitated small-group discussions about how to evaluate such innovations and recorded views on sticky notes and flipcharts.

Results

23 people attended the event. Clarity of roles and communication processes were considered important to implement the pilot project. Attendees agreed that research outcome measures should include changes in avoidable hospital admissions, emergency department attendances and 999 calls plus staff, patient and family satisfaction. They identified some potential benefits to ambulance services and general practice, such as time saved for other patients, but believed these could be difficult to measure.

Discussion

Gaining the insights of a wide range of stakeholders prior to research being designed is an important, but under-utilised approach in research development. People who deliver and receive community-based care have insight derived from personal and professional experience which complements research expertise. Research in care home settings is challenging, and insights from stakeholders were significant in the development of a research proposal about the role of paramedics in care homes (PERCH study). We submitted this to the Health and Care Research Wales Research for Public and Patient Benefit funding scheme in 2019.
OP8  What factors do ems clinicians report as influencing their decision to perform a prehospital 12 lead ECG in acute coronary syndromes?: A qualitative study
Authors: Halter Mary , Calovski Vid , Davies Glenn , Driscoll Timothy , Gale Christopher , Gavalova Lucia , Hampton Chelsey , Quinn Tom , Snooks Helen , Watkins Alan , Weston Clive
Published: September 2020

Background

International guidelines for the management of acute coronary syndromes (ACS) recommend use of the prehospital 12-lead electrocardiogram (PHECG). Research conducted before the primary PCI era suggested that PHECG is not always performed for those receiving a hospital diagnosis of ACS, with the patient’s gender and ethnicity speculated as influential.

Aim

As part of a mixed methods study investigating the use and impact of the PHECG in the primary PCI era, we explored the factors emergency medical services (EMS) clinicians report as influencing their decision to perform a PHECG.

Methods

We conducted a qualitative phenomenological study, in six focus groups with a semi structured topic guide, in three UK regions involving 47 EMS clinicians with experience ranging from nine months to 31 years. We recorded, transcribed and anonymised each focus group; familiarised ourselves with the data including notes and reflections; formed and iterated a coding framework; and constructed themes with the study team, including patient and public representatives.

Results

All participants expressed a desire to perform a prehospital ECG in patients suspected with ACS but described a setting characterised by uncertainty and ‘messy’ context. We drew out three themes of influence on the decision to perform an ECG: surface characteristics (age, sex, ethnicity, privacy, presenting condition of the patient); pattern recognition (training, experience of atypical presentations, equipment availability, confidence in interpretation); and tensions/external pressures (distance to PCI, guidelines, organisational pressures). These were interwoven by the concept of clinical autonomy.

Conclusion

Factors identified as influencing clinicians’ decision to perform a PHECG ranged from straightforward to complex and were difficult to unpick. Whilst qualitatively clinicians reported performing 12 lead PHECG wherever possible in suspected ACS, the reported multifaceted influences on the decision reinforce the need for the quantitative arm of this study to examine this nationally, alongside its association with patient outcomes.
OP9  Perch – preliminary exploration of the role of paramedics in care homes
Authors: Kingston Mark , Keen Leigh , Green Stephanie , Griffiths Lesley
Published: September 2020

Background

Half a million people live in UK care homes. General practices struggle to deliver primary care for residents due to high demand and staff shortages. Meanwhile, ambulance services are seeing an increase in 999 calls from care homes. In response, some areas are involving paramedics in proactive support to care homes, part of a shift towards paramedics undertaking non-emergency community care. Yet such workforce changes require urgent evaluation to understand implications for residents, staff and health services. We aimed to explore the role of non-emergency paramedics in care homes to support the design of portfolio research.

Methods

We convened a Research Development Group of care home, ambulance service, health board, primary care, public and academic representatives. We:

Conducted fact-finding visits to sites

Analysed 999 call data from care homes

Surveyed ENRICH (Enabling Research in Care Homes) care home managers in England and Wales

Held a stakeholder workshop to explore the issues

Results

We identified sites in England and Wales where paramedics provide non-emergency care in care homes. Operating models varied with paramedics employed by ambulance services, health boards and practices. Monthly 999 data from 300 homes confirmed high call and hospital conveyance rates. Survey respondents thought paramedics were well suited to assessing residents, identifying issues, improving care and avoiding admissions. They foresaw benefits to inter-professional working, clinical support and person-centred care, but raised concerns over professional boundaries and role clarity. These messages were reinforced in our workshop, where the value of timely assessment was highlighted, alongside challenges of funding and governance.

Conclusions

The role of paramedics is shifting into dedicated primary and community work, including care homes. It is imperative that research is aligned and informs evidence based practice. We are developing PERCH2, a feasibility study evaluating the impact of paramedics working in this way.
Unexpected cancellation on a catatonic patient’s electroconvulsive therapy due to the coronavirus pandemic
Authors: Casano Kelsey , Capone Erin
Published: September 2020

We report a case of a 39-year-old woman with a psychiatric history of schizoaffective disorder with catatonia, dependent personality disorder and substance use disorder whose symptoms have been very difficult to control. During her most recent inpatient admission, she was treated with electroconvulsive therapy (ECT) for catatonia. Our treatment team was hopeful that ECT was making a difference for this patient. However, she was only able to receive two sessions of treatment due to new hospital protocols related to the coronavirus pandemic. Although the patient was not suspected to have the coronavirus, she could no longer undergo ventilation with a bag and mask during the procedure. Bag–mask ventilation is known to aerosolise the coronavirus and other diseases and potentially put healthcare workers at risk. Although orotracheal intubation also aerosolises the coronavirus, this was the only means of airway management still allowed by anaesthesia providers at this time. Our psychiatry team estimated that the risks of intubation outweighed the benefits of treatment, and ECT was cancelled.

Without additional ECT treatments, the patient again decompensated for several weeks before being stabilised on clozapine, haloperidol and lorazepam. Although she eventually had a positive treatment outcome, her hospital course was likely prolonged due to unforeseen events related to the novel coronavirus. We feel that the current medical climate is unprecedented and is interfering with necessary psychiatric treatment in an unanticipated way. Anaesthesiologists will need to be flexible while working with psychiatrists and identify safe ways to provide this necessary psychiatric treatment for patients.
Review of current intracranial aneurysm flow diversion technology and clinical use
Authors: Dandapat Sudeepta , Mendez-Ruiz Alan , Martínez-Galdámez Mario , Macho Juan , Derakhshani Shahram , Foa Torres Gustavo , Pereira Vitor M , Arat Anil , Wakhloo Ajay K , Ortega-Gutierrez Santiago
Published: September 2020

Endovascular treatment of intracranial aneurysms (IAs) has evolved considerably over the past decades. The technological advances have been driven by the experience that coils fail to completely exclude all IAs from the blood circulation, the need to treat the diseased parent vessel segment leading to the aneurysm formation, and expansion of endovascular therapy to treat more complex IAs. Stents were initially developed to support the placement of coils inside wide neck aneurysms. However, early work on stent-like tubular braided structure led to a more sophisticated construct that then later was coined as a flow diverter (FD) and found its way into clinical application. Although FDs were initially used to treat wide-neck large and giant internal carotid artery aneurysms only amenable to surgical trap with or without a bypass or endovascular vessel sacrifice, its use in other types of IAs and cerebrovascular pathology promptly followed. Lately, we have witnessed an explosion in the application of FDs and subsequently their modifications leading to their ubiquitous use in endovascular therapy. In this review we aim to compile the available FD technology, evaluate the devices’ peculiarities from the authors’ perspective, and analyze the current literature to support initial and expanded indications, recognizing that this may be outdated soon.
Impact of a streamlined trauma management approach and determinants of mortality among hemodynamically unstable patients with severe multiple injuries: a before-and-after retrospective cohort study
Authors: Otsuka Hiroyuki , Uehata Atsushi , Sakoda Naoki , Sato Toshiki , Sakurai Keiji , Aoki Hiromichi , Yamagiwa Takeshi , Iizuka Shinichi , Inokuchi Sadaki
Published: September 2020

Background

Trauma management requires a multidisciplinary approach, but coordination of staff and procedures is challenging in patients with severe trauma. In October 2014, we implemented a streamlined trauma management system involving emergency physicians trained in severe trauma management, surgical techniques, and interventional radiology. We evaluated the impact of streamlined trauma management on patient management and outcomes (study 1) and evaluated determinants of mortality in patients with severe trauma (study 2).

Methods

We conducted a retrospective cohort study of 125 patients admitted between January 2011 and 2019 with severe trauma (Injury Severity Score ≥16) and persistent hypotension (≥2 systolic blood pressure measurements <90 mm Hg). Patients were divided into a Before cohort (January 2011 to September 2014) and an After cohort (October 2014 to January 2019) according to whether they were admitted before or after the new approach was implemented. The primary outcome was in-hospital mortality.

Results

Compared with the Before cohort (n=59), the After cohort (n=66) had a significantly lower in-hospital mortality (36.4% vs. 64.4%); required less time from hospital arrival to initiation of surgery/interventional radiology (median, 41.0 vs. 71.5 minutes); and was more likely to undergo resuscitative endovascular balloon occlusion of the aorta (24.2% vs. 6.8%). Plasma administration before initiating hemostasis (adjusted OR 1.49 (95% CI 1.04 to 2.14)), resuscitative endovascular balloon occlusion of the aorta (9.48 (95% CI 1.25 to 71.96)), and shorter time to initiation of surgery/interventional radiology (0.97 (95% CI 0.96 to 0.99)) were associated with significantly lower mortality.

Discussion

Implementing a streamlined trauma management protocol improved outcomes among hemodynamically unstable patients with severe multiple trauma.

Level of evidence

Level III.
Effect of a high‐intensity one‐week training programme and student‐level variables on the bovine transrectal palpation and pregnancy diagnosis skills of final‐year veterinary students
Authors: Annandale Annett , May Catherine E , van der Leek Martin L , Fosgate Geoffrey T , Kremer Wim DJ , Bok Harold GJ , Holm Dietmar E
Published: September 2020

Background

To improve bovine transrectal palpation (TRP) and pregnancy diagnosis (PD) training, the effect of a high‐intensity one‐week training programme for veterinary elective students (N=59) with an interest in production animal practice was evaluated.

Methods

Training consisted of exposure to rectal examination simulators, abattoir organs, theory materials and live cow PDs supervised by experienced large animal practitioners. Palpation skills were assessed before and after training using a validated TRP Objective Structured Clinical Examination (OSCE) in non‐pregnant cows. Each student then performed PDs (n=12) on cows of known pregnancy status. Students’ PD accuracy was measured as sensitivity and specificity, being respectively defined as the proportion of pregnant and non‐pregnant cows correctly identified.

Results

Students’ scores improved from the first to the second OSCE (P=0.03), mostly as a result of improved ability to identify uterine symmetry/asymmetry and the presence/absence of a corpus luteum on the right ovary (P<0.01 and P=0.03, respectively). Overall student sensitivity and specificity of PD were 89.1 per cent (95 per cent CI 78.1–92.2 per cent) and 67.7 per cent (95 per cent CI 60.1–74.5 per cent), respectively.

Conclusion

This prospective cohort study describes a strategy to improve students’ TRP skills with the potential to reduce training time and animal use at teaching institutions by outsourcing student training to private practitioners.
New gedanken experiment on higher-dimensional asymptotically AdS Reissner–Nordström black hole
Authors: Zhang Ming , Jiang Jie
Published: September 2020

Viewing the negative cosmological constant as a dynamical quantity derived from the matter field, we study the weak cosmic censorship conjecture for the higher-dimensional asymptotically AdS Reissner–Nordström black hole. To this end, using the stability assumption of the matter field perturbation and the null energy condition of the matter field, we first derive the first-order and second-order perturbation inequalities containing the variable cosmological constant and its conjugate quantity for the black hole. We prove that the higher-dimensional RN-AdS black hole cannot be destroyed under a second-order approximation of the matter field perturbation process.
Reference-frame-independent quantum key distribution with random atmospheric transmission efficiency
Authors: Xue Yang , Shi Lei , Wei Jia-Hua , Yu Long-Qiang , Yu Hui-Cun , Tang Jie
Published: September 2020

Reference-frame-independent quantum key distribution (RFI-QKD) has been proved to be tolerant against unknown reference frame misalignment, which reserves interesting prospects in implementing global quantum communication. However, few works have been addressed on the performance and feasibility for RFI-QKD in turbulent atmospheric channels. Here, we propose to implement RFI-QKD in practical free-space links with fluctuating transmission efficiency due to beam wandering and broadening. An improved model for estimating the probability distribution of single-photon receiving efficiency has been developed and we also simulated the Gaussian beam spot evolution and secure key rate based on that. Results show that the beam wandering model of probability distribution of transmission efficiency is reasonable to improve the performance of RFI-QKD in free-space channel.
Standard L1 Stability for Singular Switched Positive Systems with Time-Varying Distributed Delay Under MDRDT Constraint
Authors: Li Shuo , Zhang Junfeng , Wang Huijiao , Xiang Chengdi
Published: September 2020

This paper is concerned with the standard [Formula: see text] stability with respect to singular switched positive systems (SSPSs) with time-varying distributed delays (TVDDs) under mode-dependent ranged dwell time (MDRDT) constraint. Firstly, for SSPSs with TVDDs under MDRDT constraint, a sufficient condition of asymptotical stability is proposed. Next, to analyze disturbance attenuation performance, a sufficient condition of standard [Formula: see text] stability is presented for SSPSs with TVDDs under MDRDT constraint. Via convex optimization approach, the corresponding standard [Formula: see text]-gain performance optimum can be received. In addition, the standard [Formula: see text] stability issue is also extended to the SSPSs in nonsingular case, in delay-free case and in RDT constraint case, respectively. Finally, the validity is proved by giving three examples.
Elastic scattering of nucleon by the lightest mirror nuclei 3H and 3He using the optical model potential
Authors: Alshudifat Mohammad F. , Serhan M. , Abusini M.
Published: September 2020

The angular distribution of the nucleon elastic scattering on the lightest mirror nuclei 3H and 3He at incident energies of 6 and 9[Formula: see text]MeV has been analyzed. A new set of phenomenological optical potential parameters has been obtained. A comparison of differential cross-sections has been performed for both elastic scatterings of neutron and proton on the mirror nuclei. The contribution of individual volume, surface, and spin-orbit terms in the optical model potential for the projectiles at different energies was studied. The predicted elastic angular distributions results compared well with the experimental data.
A Novel Energy-Efficient Clustering Protocol Using Two-Stage Genetic Algorithm for Improving the Lifetime of Wireless Sensor Networks
Authors: Mahani Ali , Farahmand Ebrahim , Sheikhpour Saeide , Taheri-Chatrudi Nooshin
Published: September 2020

Wireless sensor networks (WSNs) are beginning to be deployed at an accelerated pace, and they have attracted significant attention in a broad spectrum of applications. WSNs encompass a large number of sensor nodes enabling a base station (BS) to sense and transmit data over the area where WSN is spread.

As most sensor nodes have a limited energy capacity and at the same time transmit critical information, enhancing the lifetime and the reliability of WSNs are essential factors in designing these networks. Among many approaches, clustering of sensor nodes has proved to be an effective method of reducing energy consumption and increasing lifetime of WSNs.

In this paper, a new energy-efficient clustering protocol is implemented using a two-step Genetic Algorithm (GA). In the first step of GA, cluster heads (CHs) are selected, and in the second step, cluster members are chosen based on their distance to the selected CHs. Compared to other clustering protocols, the lifetime of WSNs in the proposed clustering is improved. This improvement is the consequence of the fact that this clustering considers energy efficient parameters in clustering protocol.
A Low-Cost and High-Purity Porous Carbon Spheres Based on Starch Gel Toward High-Performance Supercapacitors
Authors: Yang Wen-Tong , Xie Hao-Yang , Li Min-Peng , Han Rong-Rong , Lu Chun , Zhang Yu-Shan , Zhang Bin-Mei , Liu Mao-Cheng
Published: September 2020

The development of low-cost, high-purity and high-performance porous carbon is of great significance for promoting the commercial application of supercapacitors. In this paper, porous carbon spheres (PCSs) with excellent electrochemical performance were obtained by carbonization and activation of starch gel spheres as precursor which is prepared by microemulsion process. The obtained PCSs exhibit both microporous and mesoporous structure, showing a large specific surface area of 1117.0 m2 g[Formula: see text] and exhibiting a high specific capacitance of 221.3 F g[Formula: see text]at a current density of 0.5 A g[Formula: see text] in aqueous electrolyte (and still displays capacity of 146.0 F g[Formula: see text] in ion liquid electrolyte). The PCSs//PCSs symmetric supercapacitor (SSC) based on aqueous electrolyte exhibits an energy density of 10.9 Wh kg[Formula: see text] at a power density of 300.0 W kg[Formula: see text], whereas that based on ion liquid electrolyte achieves a high energy density of 29.0 Wh kg[Formula: see text] at 650.0 W kg[Formula: see text]. The study provides a new idea to develop low-cost, high-purity and high-performance porous carbon materials for supercapacitors.
Observations of intracellular second-harmonic generation imaging in black phosphorus nanosheets
Authors: Peng Xiao , Song Yiwan , Peng Zheng , Nie Kaixuan , Liu Hao , Zhou Yingxin , Zhou Feifan , Yuan Yufeng , Song Jun , Qu Junle
Published: September 2020

Functionalized black phosphorus (BP) nanosheets have been considered as promising nanoagents in cancer therapy due to their excellent photothermal conversion efficiency. However, it is still difficult to visually monitor the dynamic localization of BP nanoagents in cancer cells. In this paper, we systematically studied the second-harmonic generation (SHG) signals originating from exfoliated BP nanosheets. Interestingly, under the excitation of a high frequency pulsed laser at 950 nm, the SHG signals of BP nanosheets in vitro are almost undetectable because of their poor stability. However, the intracellular SHG signals from BP nanosheets could be measured by in vivo optical [Formula: see text]imaging due to the efficient enrichment of living HeLa cells. Moreover, the SHG signal intensity from BP nanosheets increases with the prolonged incubation time. It can be expected that the BP nanosheets could be a promising intracellular SHG nanoprobe employed for visually in vivo biomedical imaging in practical cancer photothermal therapy (PIT).
Ricci almost soliton and almost Yamabe soliton on Kenmotsu manifold
Authors: Ghosh Amalendu
Published: September 2020

We prove that a Ricci almost soliton on a Kenmotsu manifold of dimension [Formula: see text] reduces to an expanding Ricci soliton satifying certain condition on the potential vector field or on the soliton function. Next, we show that any Ricci almost soliton on a Kenmotsu manifold is trivial (Einstein) if the soliton vector leaves the contact form [Formula: see text] invariant. Finally, we classify (locally) a Kenmotsu manifold admitting an almost Yamabe soliton. Some examples have been constructed of almost Yamabe solitons on different class of warped product spaces.
A complete classification of three-dimensional algebras over ℝ and ℂ — 温故知新 (visiting old, learn new)
Authors: Kobayashi Yuji , Shirayanagi Kiyoshi , Tsukada Makoto , Takahasi Sin-Ei
Published: September 2020

We provide a complete classification of three-dimensional associative algebras over the real and complex number fields based on a completely elementary proof. We list up all the multiplication tables of the algebras up to isomorphism. We compare our results with those given by mathematicians in the 19th century and this century.
On the Kähler-likeness on nearly Kähler manifolds
Authors: Kawamura Masaya
Published: September 2020

We introduce Kähler-like, G-Kähler-like almost Hermitian metrics. We characterize the Kähler-likeness and the G-Kähler-likeness, and show that these properties are equivalent on nearly Kähler manifolds. Furthermore, we prove that a nearly Kähler manifold with the Kähler-likeness is Kähler.
Analysis of Additive Alignment in a 90∘ Elbow Channel
Authors: Nguyen Hoang Minh Khoa , Oh Dong-Wook
Published: September 2020

Short-fiber reinforced polymer composites have been widely used in industrial applications due to high strength-to-weight ratio, versatile manufacturing process, and etc. The alignment of fiber type additives plays an important role in the mechanical properties of a composite material. In this paper, an injection molding process was imitated with a liquid polymer composite flow inside a [Formula: see text] elbow channel. We performed a flow visualization experiment and analyzed the additive alignment of carbon fiber flowing in the polydimethylsiloxane (PDMS) medium. By analyzing the flow visualization images, the angle changes at the corner region of the elbow channel were calculated. At the corner region, the change of passage direction leads to the change of fiber orientation. It was observed that near to the convex region, fibers have angle change values larger than the fibers traveling near to the concave region.
Manganese occurrence in the Mankwadzi Area, southern Kibi–Winneba metavolcanic belt, Ghana: typical or atypical palaeoproterozoic Birimian Mn mineralization?
Authors: Nyame Frank K. , Armah Thomas K. E. , Ibrahim Kwabina , Baah-Acheamfour Jeff , Manu Johnson , Tigme Jacob
Published: September 2020

Previous work on the manganese occurrence in the Mankwadzi area, Ghana, suggested that it resulted from localized hydrothermal or pyrometasomatic activity genetically related to dyke formation. This observation means that the Mankwadzi Mn occurrence could be genetically different from typical Birimian Mn mineralization which dominantly displays sedimentary protore and overlying, supergene-derived manganese oxides. We recently conducted field sampling, geophysical survey and petrographic analyses of the Mankwadzi Mn-bearing rocks. Our results suggest that the NNE-trending manganiferous zone, about 20–30 m wide and over 200 m long, is conformable with immediately enclosing hornblende schist. Samples of Mn rock from the manganiferous zone are generally massive to variably banded and occasionally show centimetre-scale macro-folding. Scanning electron microscope analyses revealed that bands dominated by Mn garnet often distinctly alternate with silica (chert) or siliciclastic layers. These converging lines of evidence, i.e. conformability of the manganiferous zone with enclosing rock, occurrence of distinct banding, inter-folding of manganese and silica (chert) or siliciclastic layers and alternating Mn garnet-rich and garnet-poor layers strongly suggest the Mankwadzi manganese occurrence is genetically similar to the stratiform Nsuta manganese deposit in Ghana and, more likely, to other Mn deposits in the Birimian of West Africa.
Scientists, collectors and illustrators: the roles of women in the Palaeontographical Society
Authors: Panciroli Elsa , Wyse Jackson Patrick N. , Crowther Peter R.
Published: September 2020

Women have taken on a range of roles in scientific societies since the early twentieth century. The oldest society dedicated to palaeontology, the Palaeontographical Society, was established in 1847 principally for the publication of monographs on British fossils. Since its foundation, women have been involved, initially as collectors and illustrators, then authors and latterly as elected members of council. Early contributors include well-known female scientists such as Gertrude Lilian Elles (1872–1960) and Ethel Mary Reader Wood (1871–1946), and the enigmatic ‘Miss Pike’. Although there have been female monograph authors and council members since 1901, their number has not risen significantly since the early twentieth century. The increased female presence on the Society's Council since 2009 is promising but, to date, there have been only four female vice-presidents and no female presidents in almost 175 years. Although things have undoubtedly improved since its founding, the Palaeontographical Society – like similar geosciences societies – still has some distance to travel to reach gender parity. This paper contributes to that process by recognizing the many talented women who have played formative roles in the development, and continued success, of this organization.
International geoscience cooperation – fair and equitable?
Authors: Ovadia David C. , O'Connor Eugene A.
Published: September 2020

This chapter looks at some of the ethical issues associated with international cooperation in the geosciences, which face students, researchers, academics, practitioners and others who work in this sector. It notes that the geosciences are fundamentally trans-national activities and traces the history of international cooperation from ancient times, through the era of European colonialism to the present. The drivers for international cooperation are the desire to find and extract natural resources, ways of avoiding and mitigating natural hazards through to curiosity-driven research. It identifies how altruism co-exists and sometimes competes with politics and enterprise in implementing international cooperation, and the various roles of international bodies and agencies.
Reaching out from Earth to the stars
Authors: McLean Margaret R.
Published: September 2020

Over a decade ago, Stephen Hawking cautioned, ‘I don't think that the human race will survive the next thousand years unless we spread into space. There are too many accidents that befall life on a single planet. But I'm an optimist. We will reach out to the stars’ (in Highfield 2001,
https://www.theguardian.com/commentisfree/2016/dec/01/stephen-hawking-dangerous-time-planet-inequality
). With plans afoot to pack our bags for life on the red planet in the 2030s, we should expand our ethical thinking from the Earth deep into space. This chapter proposes the development of a set of reasoning tools in the form of principles and virtue to guide scientists, the public and policy-makers in creating an ethical framework to steer and constrain our reaching out from Earth to the stars.
Biological Control with Trichogramma in China: History, Present Status, and Perspectives
Authors: Zang Lian-Sheng , Wang Su , Zhang Fan , Desneux Nicolas
Published: September 2020

Trichogramma species make up one of the most commonly used groups of natural enemies for biological control programs worldwide. Given the major successes in using Trichogramma to control economically important lepidopterous pests on agricultural crops in China, the biology and ecology of these wasps have been intensively studied to identify traits that contribute to successful biological control. Since the 1960s, improved mass production of Trichogramma and better augmentative release methods to suppress agricultural pests have been achieved. We review the history of research and development; current knowledge on biodiversity and bio-ecology of the species used; and achievements in mass-rearing methods, release strategies, and current large-scale applications in China. In addition, we discuss potential issues and challenges for Trichogramma research and applications in the future .
Marine Heatwaves
Authors: Oliver Eric C.J. , Benthuysen Jessica A. , Darmaraki Sofia , Donat Markus G. , Hobday Alistair J. , Holbrook Neil J. , Schlegel Robert W. , Sen Gupta Alex
Published: September 2020

Ocean temperature variability is a fundamental component of the Earth's climate system, and extremes in this variability affect the health of marine ecosystems around the world. The study of marine heatwaves has emerged as a rapidly growing field of research, given notable extreme warm-water events that have occurred against a background trend of global ocean warming. This review summarizes the latest physical and statistical understanding of marine heatwaves based on how they are identified, defined, characterized, and monitored through remotely sensed and in situ data sets. We describe the physical mechanisms that cause marine heatwaves, along with their global distribution, variability, and trends. Finally, we discuss current issues in this developing research area, including considerations related to thechoice of climatological baseline periods in defining extremes and how to communicate findings in the context of societal needs.
Performance and Degradation of LiFePO4/Graphite Cells: The Impact of Water Contamination and an Evaluation of Common Electrolyte Additives
Authors: Logan E. R. , Hebecker Helena , Eldesoky A. , Luscombe Aidan , Johnson Michel B. , Dahn J. R.
Published: September 2020

LiFePO4 (LFP) is an appealing cathode material for Li-ion batteries. Its superior safety and lack of expensive transition metals make LFP attractive even with the commercialization of higher specific capacity materials. In this work the performance of LFP/graphite cells is tested at various temperatures and cycling protocols. The amount of water contamination is controlled to study the impact of water on capacity fade in LFP. Further, several additive systems that have been effective in NMC/graphite chemistries are tested in LFP/graphite cells. The presence of excess water impacts cell performance severely when no electrolyte additives are used, or when the electrodes are poorly passivated. When effective additive systems are used, the existence of up to 500 ppm excess water in the cell is does not strongly affect cycle life and storage performance. Fe dissolution is studied in LFP with micro X-ray fluorescence spectroscopy (μXRF), and most electrolyte additives virtually eliminate Fe dissolution, even at high temperature and with water contamination. Removing excess water contamination suppresses Fe dissolution in cells without electrolyte additives. Finally, the capacity retention of LFP/graphite cells at high temperature is compared with long lifetime NMC/graphite cells, demonstrating challenges for LFP/graphite cells.