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This chapter focuses on how working memory develops in children who are born deaf. It includes studies of deaf users of spoken and signed languages from within the medical and social models of deafness. It also reviews how differences in working memory capacity have been explained between deaf and hearing children. It reviews the role of auditory function in the establishment of working memory, as well as consideration of language as a mediator. It concludes with a proposal that deafness leads to disrupted early exposure to language and reduced subvocal rehearsal abilities, which both impact on the operation of the working memory system.
Time-Space Compression is one of the most influential concepts in globalization theory. Focused by David Harvey in 1990 on spatial shrinkage and temporal simultaneity, it offered an account of the metaphorical contraction of the globe in relation to travel speed. This chapter explores its legacy, and argues that, since 1990, the economic and cultural meanings of time-space compression have shifted towards a conception of uncertainty: it aims to show that the vocabulary has changed in order to break with a kind of complicity that social theory has identified between capitalist expansion and social-scientific commentary. Time-space compression has turned away from the emphasis on global simultaneity, towards questions about the knowability of the future. Bernard Stiegler is one theorist who has developed a new account of epochal temporality for the digital age which has transformed canonical notions of time-space compression by giving them a future orientation. Stiegler’s work also offers us ways of thinking about narrative as a form of belatedness, and about the way that the interval between events and their reception might be eliminated by the inner forms of narrative and the novel.
This chapter presents the conceptual and analytical basics of feedback in a carefully integrated way. The analytical details presented here can also be found many other places: root locus, Black's formula, the fundamental oscillation condition, and the like are treated in many places. What is often missing in texts for the advanced student are the conceptual insights. Why, for instance, is the phase response of the loop transmission so important? What does it mean for a complex pole pair to "dominate" a system response, and why is such dominance so common? Why is open-loop control better for speed than closed-loop control? As always, conceptual understanding and analytical mastery are mutually reinforcing.
The Nyquist stability criterion ushers the advanced student into a truly deep understanding of feedback theory. To master this concept, a student needs two tools from the mathematics of complex analysis: conformal mapping and Cauchy's principle of the argument. In keeping with the goal of making this guide completely self-contained, a few pages of Chapter 4 are devoted to these topics. Afterward, we dive fully into the Nyquist criterion and show how it relates to phase margin. A few examples of Nyquist plots (using Bode plots as a guide) are also given in this chapter.
The purpose of this chapter is to further ground feedback theory in real applications with which the reader already has a great deal of real-world experience. The first section of this chapter deals with a cooling system for a room, and the second section treats the howling public address system.
To take full advantage of the ultra-dense architecture and efficiently serve the traffic with spatiotemporal fluctuation, the transmission mechanisms should be redesigned under the constraints of backhaul and energy consumption. In this chapter, we summarize and classify the spatiotemporal arrival properties of different traffic in ultra-dense networks, and optimize several promising technologies to match the traffic. A new approach based on combining stochastic geometry and queueing theory is proposed to provide a useful guidance for the design of ultra-dense networks.
Introduction: Delays in definitive management of critically ill patients are known to drive poor clinical outcomes. A scarcely studied time period in interfacility transfer is the time between initial patient presentation and the decision to transfer. This study seeks to identify patient, environmental and institutional characteristics associated with delays in decision to transfer critically ill patients by air ambulance to a tertiary care centre. Methods: Patients >18 years old who underwent emergent air ambulance interfacility transport to a tertiary care centre were included. Patient records were located in a provincial air ambulance database. The primary exposure variable was time from patient presentation to initial call to facilitate transfer. Patient, environmental and institutional characteristics were identified using stepwise variable selection at a significance of 0.1. These characteristics were then explored using quantile regression to identify significant factors associated with delay in transport initiation. Results: A total of 11231 patients were included in the analysis. There were 5009 females (44.60%) and 6222 males (55.4%). The median age of patients was 57. The median time to initiate the transfer was 3.05 hours. The variables identified with stepwise selection were gender, category of illness, heart rate, systolic blood pressure, Glasgow coma scale, vasopressor usage, blood product usage, time of day, and type of sending site. The following factors were significantly (p < 0.05) associated with an increase in time to initiate transfer compared to the reference category at the 90th centile of time: cardiac illness (+1.45h), gastrointestinal illness (+3.27h), respiratory illness (+4.90h), sepsis (+3.03h), vasopressors (+2.31h), and an evening hour of transport (+3.67h). The following factors were significantly (p < 0.05) associated with a decrease in time to initiate transfer compared to the reference category at the 90th centile of time: neurologic illness (-1.45h), obstetrical illness (-1.56h), trauma (-3.14h), GCS <8 (-0.98h), blood transfusion (-1.47h), and sending site being a community hospital >100 beds (-2.26h), <100 beds (-4.71h), or nursing station (-10.02h). Conclusion: Time to initiate transfer represents a significant window in a patient's transport journey. In looking at the predictors of early or late initiation of transfers, these findings provide education and quality improvement opportunities in decreasing time to definitive care in critically ill populations.
Taking the continuum limit of the chains of masses from the previous chapter, we arrive at the wave equation, the physical subject of this chapter. The connection to approximate string motion is an additional motivation. Viewed as a manifestation of a conservation law, the wave equation can be extended to other conservative, but nonlinear cases, like traffic flow. Mathematically, we are interested in turning partial differential equations (PDEs) into ODEs, making contact with some familiar examples. Making PDEs into ODEs occurs in a couple of ways --- the method of characteristics, and additive/multiplicative separation of variables are the primary tools.
To identify barriers and facilitators to help seeking for a dementia diagnosis from the perspective of carers and people with dementia.
A systematic review of the literature was conducted according to the PRISMA guidelines (PROSPERO protocol registration CRD42018092524). Nine electronic databases were searched for qualitative, quantitative, and mixed methods primary research studies. Two independent reviewers screened titles and abstracts, full texts of eligible studies, and conducted quality appraisal of included articles. A convergent qualitative synthesis approach was used.
From 7496 articles, 35 papers representing 32 studies from 1986 to 2017 were included. Studies originated from 13 countries across 4 continents. Barriers and facilitators were reported predominantly by carers. A small number of studies included people with dementia. Barriers included denial, stigma and fear, lack of knowledge, normalization of symptoms, preserving autonomy, lack of perceived need, unaware of changes, lack of informal network support, carer difficulties, and problems accessing help. Facilitators included recognition of symptoms as a problem, prior knowledge and contacts, and support from informal network.
Studies from a 30-year period demonstrated that barriers to help seeking persist globally, despite increasing numbers of national dementia policies. Barriers and facilitators rarely existed independently demonstrating the complexity of help seeking for a diagnosis of dementia. Multiple barriers compounded the decision-making process and more than one facilitator was often required to overcome them. Multi-faceted interventions to reduce barriers are needed, one approach would be a focus on the development of dementia friendly communities to reduce stigma and empower people with dementia and carers.
The effect of signals on stability, stable throughput region, and delay in a two-user slotted ALOHA-based random-access system with collisions is considered. This work gives rise to the development of random access G-networks, which can model security attacks, expiration of deadlines, or other malfunctions, and introduce load balancing among highly interacting queues. The users are equipped with infinite capacity buffers accepting external bursty arrivals. We consider both negative and triggering signals. Negative signals delete a packet from a user queue, while triggering signals cause the instantaneous transfer of packets among user queues. We obtain the exact stability region, and show that the stable throughput region is a subset of it. Moreover, we perform a compact mathematical analysis to obtain exact expressions for the queueing delay by solving a non-homogeneous Riemann boundary value problem. A computationally efficient way to obtain explicit bounds for the expected number of buffered packets at user queues is also presented. The theoretical findings are numerically evaluated and insights regarding the system performance are derived.
Introduction: Vast geography and low population density limit availability of specialized trauma and medical care in many areas of Ontario. As such, patients with severe illnesses often require a higher level of care than local facilities can provide and thus require an interfacility transfer to access tertiary or quaternary care. In Ontario, Ornge, a provincially run air ambulance, serves as the sole provider of air-based medical and critical care transport. Patient outcomes are impacted by the time to definitive care, yet little research about reasons for delay in interfacility transfer within Ontario has been conducted. This study aimed to identify causes of delay in interfacility transport by air ambulance in Ontario. Methods: Causes of delay were identified by manual chart review of electronic patient care records (ePCR). All emergent adult interfacility transfers for patients transported by Ornge between Jan. 1-Dec. 31, 2016 were eligible for inclusion. Patient records were flagged to be manually reviewed if they met one or more of the following criteria: 1) contained a standardized delay code; 2) the ePCR free text contained “delay”, “wait”, “duty-out”, or common misspellings therein; 3) were above the 75th percentile in total transport time; or 4) were above the 90th percentile in time to patient bedside, time spent at the sending hospital, or time to receiving facility. Each trip was categorized as having delays that fall into one or more of the following categories: time-to-sending delays, in-hospital delays, and time-to-receiving/handover delays. Results: Our search strategy identified 1,220 records for manual review and a total of 872 delays were identified. The most common delays cited included aircraft refuelling (234 delays); waiting for land EMS escort (144); and unstable patients requiring advanced care such as intubation, procedures, or transfusion (79). Other delays included handover or delays at the receiving facility (42); mechanical issues (36); dispatch-related issues (53); environmental hazards (43); staffing issues (47); and equipment problems (38). Conclusion: Some common causes of interfacility delay are potentially modifiable: better trip planning around refueling, and improved coordination with local EMS could impact many delayed interfacility trips in Ontario. Our analysis was limited by number and completeness of available records, and documentation quality. To better understand causes for delay, we would benefit from improved documentation and record availability.
The chapter utilizes an in-depth case study, which draws from in-person interviews with administrative and political elites in the German government, archival work, and secondary sources, to illustrate the likely electoral effect when hidden strategic delay fails. I trace the history of negotiations leading up to the first bailout in Greece in 2010 to analyze the electoral effects of EU negotiations in Germany. The case study is particularly interesting, because it is a case of “failed” delay. Due to a large segment of the population opposing a financial rescue package for Greece and an important regional election, the German government had attempted to delay a bailout to Greece until after the election, publicly stating that it opposed such a bailout. Because of an unexpected and very rapid deterioration of the economic situation in Greece and the Eurozone, the German government agreed to a bailout just a week before the election. The case provides us with a rare chance to analyze the counterfactual in a situation where the delay did not work. In this situation, my theory would predict the German government would lose public approval as a consequence. Supporting this, I demonstrate in the case study that voters were opposed to the bailout and punished the German government for its decision to pursue it.
This chapter gives a detailed discussion of delay arising as an issue at the leave stage in an application for judicial review. The relevant principles and rules are introduced, followed by an explanation of the requirement for promptness. The various reasons which may justify an extension of time are then explored, followed by a consideration of the rule that the court has discretion to refuse to grant leave or any relief sought on the application for judicial review if it considers that the granting of relief sought would be likely to cause substantial hardship to, or substantially prejudice the rights of, any person or would be detrimental to good administration.
The signal transduction pathway is the important process of communication of the cells. It is the dynamical interaction between the ligand-receptor complexes and an inhibitor protein in second messenger synthesis. The signaling molecules are detected and bounded by receptors, typically G-Protein receptors, across the cell membrane and that in turns alerts intracellular molecules to stimulate a response or a desired consequence in the target cells. In this research, we consider a model of the signal transduction process consisting of a system of three differential equations which involve the dynamic interaction between an inhibitor protein and the ligand-receptor complexes in the second messenger synthesis. We will incorporate a delay τ in the time needed before the signal amplification process can take effect on the production of the ligand-receptor complex. We investigate persistence and stability of the system. It is shown that the system allows positive solutions and the positive equilibrium is locally asymptotically stable under suitable conditions on the system parameters.
We investigated the extent of delays in the response time of emergency medical services (EMS) as an impact of mass casualty incidences (MCIs) in the same area.
We defined an MCI case as an event that resulted in 6 or more patients being transported by EMS, and prehospital response time as the time from the call to arrival at the scene. We matched patients before and after MCIs by dividing them into categories of 3 hours before, 0-1 hour after, 1-2 hours after, and 2-3 hours after the MCIs. We compared prehospital response times using multiple linear regression.
A total of 33,276 EMS-treated patients were matched. The prehospital response time for the category of 3 hours before the MCIs was 8.8 minutes (SD: 8.2), treated as the reference, whereas that for the category of 0-1 hour after the MCI was 11.3 minutes (P<0.01). The multiple linear regression analysis revealed that prehospital response time increased by 2.5 minutes (95% CI: 2.3-2.8) during the first hour and by 0.3 minutes (95% CI: 0.1-0.6) during the second hour after MCIs.
There were significant delays in the prehospital response time for emergency patients after MCIs, and it lasted for 2 hours as the spillover effect. (Disaster Med Public Health Preparedness. 2018;12:94–100)
We present a detailed derivation and analysis of a model consisting of seven coupled delay differential equations for louse-borne relapsing fever (LBRF), a disease transmitted from human to human by the body louse Pediculus humanus humanus. Delays model the latency stages of LBRF in humans and lice, which vary in duration from individual to individual, and are therefore modelled using distributed delays with relatively general kernels. A particular feature of the transmission of LBRF to a human is that it involves the death of the louse, usually by crushing which has the effect of releasing the infected body fluids of the dead louse onto the hosts skin. Careful attention is paid to this aspect. We obtain results on existence, positivity, boundedness, linear and nonlinear stability, and persistence. We also derive a basic reproduction number R0 for the model and discuss its dependence on the model parameters. Our analysis of the model suggests that effective louse control without crushing should be the best strategy for LBRF eradication. We conclude that simple measures and precautions should, in general, be sufficient to facilitate disease eradication.
We derive a stage-structured model for an insect population in which a larva matures on reaching a certain size, and in which there is intra-specific competition among larvae that hinders their development, thereby prolonging the larval phase. The model, a system of delay differential equations for the total numbers of adults and larvae, assumes two forms. One of these is a system with a variable state-dependent time delay determined by a threshold condition, the other has constant and distributed delays, a size-like independent variable replacing time t, and no threshold condition. We prove theorems on boundedness and on the linear stability of equilibria.
Intra-specific competition in insect and amphibian species is often experienced in completely different ways in their distinct life stages. Competition among larvae is important because it can impact on adult traits that affect disease transmission, yet mathematical models often ignore larval competition. We present two models of larval competition in the form of delay differential equations for the adult population derived from age-structured models that include larval competition. We present a simple prototype equation that models larval competition in a simplistic way. Recognising that individual larvae experience competition from other larvae at various stages of development, we then derive a more complex equation containing an integral with a kernel that quantifies the competitive effect of larvae of age ā on larvae of age a. In some parameter regimes, this model and the famous spruce budworm model have similar dynamics, with the possibility of multiple co-existing equilibria. Results on boundedness and persistence are also proved.
This work focuses on finding optimal dividend payment and capital injection policies to maximize the present value of the difference between the cumulative dividend payment and the possible capital injections with delays. Starting from the classical Cramér–Lundberg process, using the dynamic programming approach, the value function obeys a quasi-variational inequality. With delays in capital injections, the company will be exposed to the risk of financial ruin during the delay period. In addition, the optimal dividend payment and capital injection strategy should balance the expected cost of the possible capital injections and the time value of the delay period. In this paper, the closed-form solution of the value function and the corresponding optimal policies are obtained. Some limiting cases are also discussed. A numerical example is presented to illustrate properties of the solution. Some economic insights are also given.
This paper is concerned with the Hopf bifurcation analysis of tumor-immune system competition model with two delays. First, we discuss the stability of state points with different kinds of delays. Then, a sufficient condition to the existence of the Hopf bifurcation is derived with parameters at different points. Furthermore, under this condition, the stability and direction of bifurcation are determined by applying the normal form method and the center manifold theory. Finally, a kind of Runge-Kutta methods is given out to simulate the periodic solutions numerically. At last, some numerical experiments are given to match well with the main conclusion of this paper.