The Continuum
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Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Kaili Sun ◽  
Zongshan Zhao ◽  
Yangjian Cai ◽  
Uriel Levy ◽  
Zhanghua Han

Abstract The development of novel and cost-effective THz emitters, with properties superior to current THz sources, is an active and important field of research. In this work, we propose and numerically demonstrate a simple yet effective approach of realizing terahertz sources working in continuous-wave form, by incorporating the new physics of bound state in the continuum (BIC) into thermal emitters. By deliberately designing the structure of slotted disk array made of high-resistivity silicon on top of a low index dielectric buffer layer supported by a conducting substrate, a quasi-BIC mode with ultra-high quality factor (∼104) can be supported. Our results reveal that the structure can operate as an efficient terahertz thermal emitter with near-unity emissivity and ultranarrow bandwidth. For example, an emitter working at 1.3914 THz with an ultranarrow linewidth less than 130 MHz, which is roughly 4 orders of magnitude smaller than that obtained from a metallic metamaterial-based thermal emitter, is shown. In addition to its high monochromaticity, this novel emitter has additional important advantages including high directionality and linear polarization, which makes it a promising candidate as the new generation of THz sources. It holds a great potential for practical applications where high spectral resolving capability is required.

2021 ◽  
Vol 121 (11) ◽  
pp. 2310-2313
Tony Peregrin

2021 ◽  
Vol 2 (5) ◽  
pp. 6770-6792
Santiago U. Sánchez Jiménez

La vaguedad es una propiedad inherente de las lenguas naturales y, también, una estrategia discursiva eficaz. En este trabajo se presta atención a los rasgos de la vaguedad lingüística, a los motivos que justifican su existencia, a los tipos de vaguedad y a la relación que se establece con otros procesos semánticos como la polisemia, la homonimia o la modalidad epistémica. La vaguedad intencional (la que persigue un fin comunicativo) ha de enmarcarse dentro del contínuum precisión-imprecisión. En el ámbito de la vaguedad intencional ha de distinguirse una vaguedad pragmática (generada por el contexto) y otra vaguedad lingüística, consistente en el empleo de elementos lingüísticos que estrechan el margen de precisión o amplían el espectro de la vaguedad. La posibilidad de que el emisor pueda intervenir en el grado de precisión o imprecisión de una expresión lingüística pone de manifiesto la elasticidad del idioma. Vagueness is an inherent property of natural languages ​​and also an effective discursive strategy. In this work attention to features of linguistic vagueness, the reasons for their existence, the types of vagueness and the relationship established with other semantic processes such as polysemy, homonyms or epistemic modality is provided. The intentional vagueness (which pursues a communicative purpose) must fit within the continuum of precision-vagueness. In the field of intentional vagueness we have to distinguish a pragmatic vagueness (generated by the context) and other linguistic vagueness, consisting of the use of linguistic elements that narrow the margin of precision or broaden the spectrum of vagueness. The possibility that the speaker may select the degree of accuracy or inaccuracy of a linguistic expression shows the elasticity of language.  

2021 ◽  
Vol 11 (1) ◽  
L. S. Lima

AbstractSpin-transport and current-induced torques in ferromagnet heterostructures given by a ferromagnetic domain wall are investigated. Furthermore, the continuum spin conductivity is studied in a frustrated spin system given by the Heisenberg model with ferromagnetic in-chain interaction $$J_1<0$$ J 1 < 0 between nearest neighbors and antiferromagnetic next-nearest-neighbor in-chain interaction $$J_2>0$$ J 2 > 0 with aim to investigate the effect of the phase diagram of the critical ion single anisotropy $$D_c$$ D c as a function of $$J_2$$ J 2 on conductivity. We consider the model with the moderate strength of the frustrating parameter such that in-chain spin-spin correlations that are predominantly ferromagnetic. In addition, we consider two inter-chain couplings $$J_{\perp ,y}$$ J ⊥ , y and $$J_{\perp ,z}$$ J ⊥ , z , corresponding to the two axes perpendicular to chain where ferromagnetic as well as antiferromagnetic interactions are taken into account.

2021 ◽  
Vol 8 ◽  
Audrey Borghi-Silva ◽  
Adriana S. Garcia-Araújo ◽  
Eliane Winkermann ◽  
Flavia R. Caruso ◽  
Daniela Bassi-Dibai ◽  

Among the most prevalent multimorbidities that accompany the aging process, chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) stand out, representing the main causes of hospital admissions in the world. The prevalence of COPD coexistence in patients with CHF is higher than in control subjects, given the common risk factors associated with a complex process of chronic diseases developing in the aging process. COPD-CHF coexistence confers a marked negative impact on mechanical-ventilatory, cardiocirculatory, autonomic, gas exchange, muscular, ventilatory, and cerebral blood flow, further impairing the reduced exercise capacity and health status of either condition alone. In this context, integrated approach to the cardiopulmonary based on pharmacological optimization and non-pharmacological treatment (i.e., exercise-based cardiopulmonary and metabolic rehabilitation) can be emphatically encouraged by health professionals as they are safe and well-tolerated, reducing hospital readmissions, morbidity, and mortality. This review aims to explore aerobic exercise, the cornerstone of cardiopulmonary and metabolic rehabilitation, resistance and inspiratory muscle training and exercise-based rehabilitation delivery models in patients with COPD-CHF multimorbidities across the continuum of the disease. In addition, the review address the importance of adjuncts to enhance exercise capacity in these patients, which may be used to optimize the gains obtained in these programs.

2021 ◽  
Haoran Wu ◽  
Jingjun Yu ◽  
Jie Pan ◽  
Xu Pei

Abstract The inverse kinematics of continuum robot is an important factor to guarantee the motion accuracy. How to construct a concise inverse kinematics model is very essential for the motion control of continuum robot. In this paper, a new method for solving the inverse kinematics of continuum robot is proposed based on the geometric and numerical method. Assumed that the deformation of the continuum robot is Piecewise Constant Curvature model (PCC), the envelope surface of the continuum robot based on single-segment is modeled and calculated. The clustering method is used to calculate the intersection of the curves. Then, a distinct sequence is designed for solving the inverse kinematics of continuum robot, and it is also suitable for the multi-segment continuum robots in space. Finally, the accuracy of the inverse kinematics algorithm is verified by the simulation and numerical experiment. The experiment results illustrate that this algorithm is with higher accuracy compared with the Jacobian iterative algorithm.

2021 ◽  
Simiso M. Ntuli ◽  
D M Letswalo

Abstract Background Diabetic foot amputations are the most devastating outcome for any diabetic patient and could be associated with failure to risk stratify the diabetic foot and create individualised treatment plans to lower risk at the primary healthcare level (PHC). In South Africa (RSA), PHC clinics are the first entry point to the public healthcare system. Failure to correctly identify, risk categorise, and refer diabetic foot complications may lead to poor clinical outcomes for diabetic patients. There is a need to highlight poor clinical outcomes and link them to limited access to foot health services at the PHC level. This approach may help drive the strategic allocation and deployment of limited podiatry force in RSA. This study looks at the incidence of diabetic-related amputations at central and tertiary hospitals in Gauteng to argue the case of the needed foot health services at the PHC level. Methods A cross-sectional retrospective study that reviewed theatre records. We reviewed records of all diabetic patients who had diabetic-related amputations between January 2017 and June 2019. Results There were 1862 diabetic-related amputations; however, only 1565 accurately recorded and met the inclusion criteria for the study. The first amputation was a major amputation in 73% of the cases, and an infected foot ulcer was a primary amputation cause in 75% of patients. Males had the most amputations, 62%. The majority, 71% of amputations, were in patients younger than 65 years. Nearly all patients (98%) came from a poor socio-economic background and are state-dependent; they earned ZAR 0.00- 70 000.00 or USD (0.00- 4754.41) per annum. Conclusion Amputations are a sign of poor clinical outcomes for diabetic patients and imply inadequate care of diabetic foot complications across the continuum of care, particularly at the PHC level in RSA. Due to the hierarchal nature of healthcare delivery in RSA, all patients in this study would have presented at a PHC facility to manage their diabetes and other chronic comorbidities. The findings show that most first amputations recorded in this study were major amputations. This finding is a significant signpost of the potential delay in recognising, treating and timely referral of diabetic-related foot complications. Arguably, a lack of access to structured foot health services at PHC levels impedes early identification of foot complication identification and appropriate referral resulting in the amputation in some of the patients.

2021 ◽  
pp. 095646242110469
Susanna A Abraham ◽  
Sheila E Clow

Uptake of services and retention throughout the Prevention of Mother-to-Child Transmission continuum are necessary to achieve the goal of reducing Mother-to-Child Transmission of Human Immunodeficiency Virus (HIV). Adopting a retrospective cohort design, we tracked the uptake of services in a district hospital in Ghana from antenatal booking through to six weeks postnatal when early infant diagnosis was conducted. Of the 1252 pregnant women booked antenatally, 94.1% ( n = 1178) received pre-test counselling, 96.3% (1134) opted for HIV testing and 3.8% ( n = 43) women tested positive for HIV throughout the continuum. The retention rate at six weeks postpartum was 67.4%. Missed opportunities occurred throughout the programme and the highest disengagement, 58.9% (23/39) occurred antenatally. Instances of re-engagement were also recorded. Establishing measures to promote retention throughout the programme is critical to ensuring HIV-infected mothers maintain their health and their exposed newborns are HIV-free. This phase of the study provided a comprehensive view of retention in the absence of any baseline.

2021 ◽  
Vol 18 (1) ◽  
Willy Dunbar ◽  
Marie Colette Alcide Jean-Pierre ◽  
Jacky S. Pétion ◽  
Aline Labat ◽  
Nathalie Maulet ◽  

Abstract Background Men who have Sex with Men (MSM) represent the risk group that are disproportionately most affected by the human immunodeficiency virus (HIV) and continue to drop-off from the steps of the continuum of HIV services that have been adopted to overcome poor engagement and retention in care. This realist evaluation aimed at: (1) describing the evaluation carried out in Haiti aiming to ascertain why, how and under which circumstances MSM are linked and retained along the continuum, (2) assessing the outcomes of this approach and (3) exploring the motivators and facilitators for the HIV continuum of services through mechanisms and pathways. Methods Guided by a realist approach, first, an initial program theory (IPT) was developed based on literature and frameworks review, participant observations and discussions with stakeholders. Then, the IPT was tested using a mixed method explanatory study: a quantitative phase to build the continuum from a cross-sectional analysis, and a qualitative phase to explore the motivators and facilitators related to proper linkages along the continuum. Finally, the IPT was refined by eliciting the mechanisms and pathways for outcomes improvement. Results The results showed that the current service delivery model is suboptimal in identifying, engaging, linking and retaining MSM, resulting in loss to follow-up at every step of the continuum and failure to fully realize the health and prevention benefits of antiretroviral. However, the mechanisms through which linkages across the continuum can be improved are: self-acceptance, sense of community support and sense of comprehensive and tailored HIV services. These mechanisms are based on 10 different pathways: self-esteem, awareness and pride, perception of HIV risk, pcceptance and HIV status, addressing community stigma, strengthening of MSM organizations and community networks, societal acceptation and tolerance, stigma reduction training for healthcare providers, engagement of peers as educators and navigators and, adapted services delivery through drug dispensing points and mobile technology and financial assistance. Conclusions The study findings show that engagement, adherence and retention to the continuum of HIV service for MSM are affected by a multi-layer of factors, thus highlighting the importance of taking a comprehensive approach to improve the program.

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5907
Dingjun Li ◽  
Fan Sun ◽  
Cheng Ye ◽  
Peng Jiang ◽  
Jianpu Zhang ◽  

The degradation mechanisms for environmental barrier coatings (EBCs) under high-temperature water vapour conditions are vital for the service of aero-engine blades. This study proposes a theoretical model of high-temperature water vapour corrosion coupled with deformation, mass diffusion and chemical reaction based on the continuum thermodynamics and the actual water vapour corrosion mechanisms of an EBC system. The theoretical model is suitable for solving the stress and strain fields, water vapour concentration distribution and coating corrosion degree of an EBC system during the water vapour corrosion process. The results show that the thickness of the corrosion zone on the top of the EBC system depended on water vapour diffusion, which had the greatest influence on the corrosion process. The top corroded area of the rare-earth silicate EBC system was significantly evident, and there was a clear dividing line between the un-corroded and corroded regions.

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