Critical Delay Research Articles

Rapid Phenotypic Antibiotic Susceptibility Profiling of Clinical Escherichia coli and Klebsiella pneumoniae Blood Cultures.

Bloodstream infections (BSI) are defined by the presence of viable bacteria or fungi, accompanied by systemic signs of infection. Choosing empirical therapy based solely on patient risk factors and prior antibiotic susceptibility test (AST) may lead to either ineffective treatment or unnecessarily broad-spectrum antibiotic exposure. In general, Clinical & Laboratory Standards Institute guideline-approved ASTs have a turnaround time of 48-72 h from sample to answer, a period that may result in a critical delay in the appropriate selection of therapy. Therefore, reducing the time required for AST is highly advantageous. We have previously shown that our novel rapid AST method, MAPt (Micro-Agar-PCR-test), accurately identifies susceptibility profiles for spiked bioterrorism agents like Bacillus anthracis, Yersinia pestis and Francisella tularensis directly from whole-blood and blood culture samples, even at low bacterial levels (500 CFU/mL). This study evaluated the performance of MAPt on routine bloodstream infection (BSI), focusing on Escherichia coli and Klebsiella pneumoniae isolates from clinical cultures, including resistant strains to some of the six tested antibiotics. Notably, MAPt yielded results exceeding 95% agreement with the standard hospital method within a significantly shorter timeframe of 6 h. These findings suggest significant potential for MAPt as a rapid and reliable BSI management tool.

Further Results on the Input-to-State Stability of a Linear Disturbed System with Control Delay

In this paper, a theorem is obtained that gives sufficient input-to-state stability conditions for linear systems with control delay and additive disturbances. Stabilizing feedback is considered available in the absence of delay and disturbances. The mathematical tools are the Lyapunov–Krasovskii functional, the Jensen inequality and the double Hadamard inequality. The critical delay is highlighted.

Time to Treatment Initiation and HIV Viral Suppression in People Diagnosed With HIV-1 During COVID-19 Pandemic in Ex-Aquitaine, France (ANRS CO3 AQUIVIH-NA Cohort-QuAliCOV Study).

The COVID-19 pandemic's impact on initiation and effectiveness of antiretroviral therapy (ART) in people diagnosed with HIV remains unclear. We evaluated critical delays in HIV care in people diagnosed before and during the pandemic in ex-Aquitaine, France. We considered adults diagnosed with HIV-1 in 2018-2021 and enrolled in the ANRS CO3 AQUIVIH-NA and followed them until October 10, 2022 for those diagnosed during the pandemic (April 01, 2020-December 31, 2021) and until March 31, 2020 for historical controls. We compared their characteristics at inclusion and the median time between diagnosis and ART initiation, ART initiation and viral suppression, and diagnosis and virologic, suppression (effective management). Eighty-three individuals were diagnosed during the pandemic versus 188 during the prepandemic period. Median follow-up was 549 (interquartile range: 329-713) days. Populations were similar in sex, age, HIV acquisition mode, hospital type, and clinical characteristics at diagnosis; however, fewer were foreign-born during the pandemic (15.7% versus 33.5%, P = 0.003). The probability of ART initiation, therapeutic success, and effective management was higher in people living with HIV (PLWH) diagnosed during the pandemic in adjusted analyses (hazard ratio [HR]: 2.0; 95% CI: 1.5 to 2.7; HR: 1.7; 95% CI: 1.2 to 2.3; HR: 1.8; 95% CI: 1.3 to 2.6, respectively). Those diagnosed during the pandemic were 2.3 (95% CI: 1.2 to 4.1) times more likely to be virologically suppressed within six months of diagnosis compared with historical controls. Pandemic-related reorganizations may have resulted in newly diagnosed PLWH being prioritized; however, the lower proportion of foreign-born PLWH diagnosed during the pandemic period, likely because of reduced migration and potential delays in diagnosis, may contribute to these preliminary findings.

Modeling and analysis of demand-supply dynamics with a collectability factor using delay differential equations in economic growth via the Caputo operator

<abstract> <p>In this paper, to investigate the dynamic interplay between supply and demand, with a focus on collectability, a novel mathematical model was introduced via conformable operator. This model considers the possibility that operating expenses or a lack of raw materials causes a manufacturing delay than the supply of goods instantly matching demand. This maturation (delay) is represented by the delay factor $ \left(\tau \right) $. Stability analysis revolves around the equilibrium point other than zero. Chaotic behavior emerges through Hopf bifurcation at the critical delay parameter value. If this delay parameter is even slightly perturbed, oscillatory limit cycles can be induced in the market dynamics, leading to equilibrium with brisk market expansion, frequent recessions, and sudden collapses. We conducted sensitivity and directional analysis on a number of factors while also examining the stability and duration of the Hopf bifurcation. Numerical findings were validated using MATLAB. Additionally, the Caputo operator was used to examine the fractional of demand and supply dynamics. Importantly, we assumed a pivotal role in advancing fair labor practices and fostering economic growth on a national scale.</p> </abstract>

Increasing U.S. Maternal Health Equity Among Immigrant Populations Through Community Engagement

Immigrant women in the United States are at an elevated risk of poor maternal health outcomes due to cultural, linguistic, or socioeconomic barriers that may lead to critical delays in obtaining adequate health care. Ensuring access to high-quality, culturally appropriate perinatal health care is crucial to improve the health and well-being of immigrant mothers and their children. Various aspects of perinatal health care for immigrant women can be improved through community engagement strategies. Barriers can be addressed by involving community members in designing and delivering culturally appropriate maternal health services. Some strategies discussed in this commentary include working with community health workers, encouraging telehealth through community health workers, providing breastfeeding and mental health support within cultural norms, and involving community-based doulas and midwives.

A machine learning based column-and-row generation approach for integrated air cargo recovery problem

Freighter airlines need to recover both aircraft and cargo schedules when disruptions happen. This process is usually divided into three sequential decisions to recover flights, aircraft, and cargoes. This study focuses on the integrated recovery problem that makes aircraft and cargo recovery decisions simultaneously. We formulate a string-based model to solve the integrated air cargo recovery problem. The main difficulty of the string-based model is that the number of constraints grows with the newly generated flight delay decisions in the variable generation subproblem. Therefore, the traditional column generation method can not be applied directly. To tackle this challenge, we propose a machine learning-based column-and-row generation approach. The machine learning method is used to uncover the critical delay decisions of short through connections in each column-and-row generation iteration by eliminating the poor flight delay decisions. We also propose a set of valid inequality constraints that can greatly improve the objective of LP relaxation solution and reduce the integral gap. The effectiveness and efficiency of our model are tested by simulated scenarios based on real operational data from the largest Chinese freighter airline. The computational results show that a significant cost reduction can be achieved with the proposed integrated model in a reasonable time.

Fundamental Experiment of Ignition and Flame Development in Turbulent Jet Ignition Ignited Methane Jet Flame

ABSTRACT In heavy-duty natural gas engines, diesel is usually injected before natural gas to initiate methane combustion. However, such an approach requires additional fuel and precise injection strategies. In the present work, an alternative approach of pre-chamber turbulent jet ignition (TJI) ignited methane jet flame is performed experimentally. The underlying mechanism of TJI-HPDI jet combustion is investigated in an optically visualized constant-volume combustion chamber with an active pre-chamber. It is found that with the increase of the injection-ignition delay (ti), the combustion process undergoes several transitions. In addition, the success ignition region and ignition failure region separated by ti and T MI are discerned on the ti-T MI diagram. As ti increases, there is an initial rise in both the mean flame front velocity and peak pressure, followed by a subsequent decrease This behavior highlights the TJI-HPDI system’s notable advantages in expanding the lean combustion limit and enhancing overall combustion characteristics compared to premixed combustion. These advantages can be attributed to the mixture stratification and turbulence. Furthermore, pre-chambers fueled with hydrogen can further improve the intensity and energy of the turbulent hot jet, which further decreases the critical injection-ignition delay to initiate global flame propagation in the TJI-HPDI system. The present work deals with real engineering technologies, and it will provide new insights into the design and control of TJI-HPDI engines, especially for heavy-duty natural gas engines.

Accelerating DSP Applications on a 16-Bit Processor: Block RAM Integration and Distributed Arithmetic Approach

Modern processors have improved performance but still face challenges such as power consumption, storage limitations, and the need for faster processing. The 16-bit Digital Signal Processors (DSPs) accelerate DSP applications by significantly enhancing speed and performance for tasks including audio processing, telecommunications, image and video processing, wireless communication, and consumer electronics. This paper presents a novel technique for accelerating DSP applications on a 16-bit processor by combining two methods: Block Random Access Memory (BRAM) and Distributed Arithmetic (DA). Integrating BRAM as a replacement for conventional RAM minimizes timing and critical route delays, improving processor efficiency and performance. Furthermore, the Distributed Arithmetic approach enhances performance and efficiency by utilizing precomputed lookup tables to expedite multiplication operations within the Arithmetic and Logic Unit (ALU). We use the Xilinx Vivado tool, a robust development environment for FPGA-based systems, for the design process and execute the hardware implementation using the Genesys2 Kintex board. The proposed work produces improved efficiency with a cycle per instruction of 2, where the delay is 2.009 ns, the critical path delay is 8.182 ns, and the power consumption is 4 mW.

Echo threshold measurement based on headphone presentation

Echo threshold(ET), as the upper threshold of the precedence effect, refers to the critical delay value when the listener transitions from perceiving a single fused sound image to two clear and separated sound images in the presence of two relatively delayed sounds. This study investigates the ET measurement using two kinds of headphone-based virtual sound source presentation methods, i.e., interaural time difference (ITD) lateralization and virtual auditory synthesis (VAS). The “lead-lag” paradigm was adopted in the experiment and an adaptive up-down procedure was used to measure ETs of four stimuli, including noise burst, speech, music and pink noise. The results demonstrate that ET is related to the type of signal and the presentation method. Long-duration signals (i.e., speech, music and pink noise) have greater ETs than short-duration signal(noise burst), which is due to the fact that the temporal overlap between lead and lag sound of long-duration signal would suppress the identification of the lag. ETs of ITD-based presentation were significantly greater than that of VAS-based method for long-duration signal, which indicate that different spatial cues produced by different presentation methods would influence the ET of long-duration signal.

Analysis of Three Delays of Maternal Mortality in Federal Government Polyclinic Islamabad

Analysis of Three Delays of Maternal Mortality in Federal Government Polyclinic Islamabad

Gaucher disease prevalence in 600 patients affected by monoclonal gammopathy of undetermined significance.

Gaucher disease (GD) is a rare autosomal recessive inherited disorder caused by the lysosomal enzyme acid β-glucosidase deficiency. Many patients experience a critical delay in the diagnosis of up to 8-10 years due to its rarity and variability in signs and symptoms, with the consultation of several specialists. This prospective observational study analyzed the prevalence of GD in 600 patients with monoclonal gammopathy of uncertain significance (MGUS) from January 2018 until February 2022. The mean age of participants was 66 years, with a mean monoclonal component of 0.58 g/dL. In 433 MGUS patients with available data, anemia (hemoglobin level < 10 g/dL) was present in 31 patients (7%), and thrombocytopenia (platelet count <100.000/mm3 ) in 24 (5.5%). Of 600 MGUS patients tested for acid β-glucosidase enzyme activity, 7 patients (1.2%) had activity below 2.5 nmol/h/mL. In comparison, GBA gene analysis was executed in 110 patients. It revealed 4 patients (0.7%) affected by GD (3 patients with compound heterozygous mutation and 1 with homozygous mutation), with a prevalence of 1 every 150 MGUS patients. Furthermore, 12 out of the remaining 106 evaluated patients (11%) were carriers of a single heterozygous mutation while having regular enzyme activity. The clinical heterogeneity of GD and frequent lack of awareness among physicians often lead to diagnostic delays and severe clinical manifestations. The role of MGUS in the presence of at least one clinical sign, such as low platelet count, organomegaly, bone pain, or bleeding tendency, could aid in initiating GD screening with DBS, thus reducing the period between symptom onset and the diagnosis of this rare disease.

Experimental observation of the TJI-initiated HPDI gas combustion: Vertically crossed flame jet and methane jet

In the field of natural gas marine engines, the high-pressure direct injection (HPDI) technology is widely used to achieve emission reduction while maintaining equivalent thermal efficiency and power output compared to diesel engines. In these engines, the in-cylinder combustion is primarily initiated by the diesel spray flame near the top dead center (TDC). In the present work, pre-chamber turbulent jet ignition (TJI) is employed to substitute diesel injection to initiate the combustion of HPDI methane jets. The optical experiments of ignition and flame development in the TJI-HPDI system with various injector configurations and injection/ignition control parameters are conducted in a constant-volume combustion chamber (CVCC). It is revealed that with the increase of injection-ignition delay(ti), three ignition modes are observed sequentially: methane jet suppresses ignition, methane jet first suppresses ignition then promotes flame propagation, and direct ignition and promoted flame propagation. The effect of various injection-ignition delays and injection pulse width were explored. The injection-ignition delay significantly influences the combustion characteristics such as heat release rate, while the injection pulse width influences the duration of the lifted jet flame. The flame lift-off length first decreases and then increases due to variations in thermodynamic conditions and oxygen concentration. With a larger-nozzle injector, the critical injection-ignition delay to initiate the main chamber combustion is significantly reduced. Moreover, the use of different nozzle diameters leads to varying levels of turbulent intensity in the methane jet, which in turn affects the combustion behavior.

Technique to derive discrete population models with delayed growth

We provide a procedure for deriving discrete population models for the size of the adult population at the beginning of each breeding cycle and assume only adult individuals reproduce. This derivation technique includes delay to account for the number of breeding cycles that a newborn individual remains immature and does not contribute to reproduction. These models include a survival probability (during the delay period) for the immature individuals, since these individuals have to survive to reach maturity and become members of, what we consider, the adult population. We discuss properties of this class of discrete delay population models and show that there is a critical delay threshold. The population goes extinct if the delay exceeds this threshold. We apply this derivation procedure to obtain two models, a Beverton–Holt adult model and a Ricker adult model and discuss the global dynamics of both models.

Systematic review of construction project delays in Kuwait

Over the past two decades, numerous global studies, including those conducted in Kuwait, have focused on examining and understanding delays in construction projects. These investigations aimed to identify causes of delays and rank them based on their impact on project objectives. In pursuit of this research goal, the present study adopts a systematic approach to analyze construction delays, building on related previous research efforts. The primary objective of this analytical approach was to determine the most significant and influential causes of delays and investigate changes in these causes over the span of two decades, during which measures were taken to address delays. Through comprehensive analyses, the critical delay causes within the Kuwaiti construction industry were identified as: contractor site management incompetence, subcontractor-related challenges, design quality deficiencies, problems arising from the used contract, and supply chain disruptions affecting labor availability and construction materials. Additionally, the body of research on the subject was divided into two distinct groups: studies conducted before and after the year 2010. A comparative examination of the outcomes from these two groups revealed notable enhancement for internal site management delay sources, which involve direct management teams including contractors, supervisors, and owners, whereas the influence of external delay causes increased, primarily attributed to the impact of governmental regulations. To assess the dissimilarities between the results of these two groups, an ANOVA analysis was applied, affirming the presence of statistically significant differences. The study concludes by emphasizing key areas requiring further attention to effectively mitigate the causes of delays in construction projects. Moreover, the proposed analysis procedure holds potential applicability to other countries, serving as a valuable tool to augment the understanding of delay analysis within the construction domain on a broader scale.

Impact of CoronaVac on Covid-19 outcomes of elderly adults in a large and socially unequal Brazilian city: A target trial emulation study

BackgroundAlthough CoronaVac was the only Covid-19 vaccine adopted in the first months of the Brazilian vaccination campaign, randomized clinical trials to evaluate its efficacy in elderly adults were limited. In this study, we use routinely collected surveillance and SARS-CoV-2 vaccination and testing data comprising the population of the fifth largest city of Brazil to evaluate the effectiveness of CoronaVac in adults 60+ years old against severe outcomes. MethodsUsing large observational databases on vaccination and surveillance data from the city of Fortaleza, Brazil, we defined a retrospective cohort including 324,302 eligible adults aged ≥60 years to evaluate the effectiveness of the CoronaVac vaccine. The cohort included individuals vaccinated between January 21, 2021, and August 31, 2021, who were matched with unvaccinated persons at the time of rollout following a 1:1 ratio according to baseline covariates of age, sex, and Human Development Index of the neighborhood of residence. Only Covid-19-related severe outcomes were included in the analysis: hospitalization, ICU admission, and death. Vaccine effectiveness for each outcome was calculated by using the risk ratio between the two groups, with the risk obtained by the Kaplan-Meier estimator. ResultsWe obtained 62,643 matched pairs for assessing the effectiveness of the two-dose regimen of CoronaVac. The demographic profile of the matched population was statistically representative of the population of Fortaleza. Using the cumulative incidence as the risk associated with each group, starting at day 14 since the receipt of the second dose, we found an 82.3 % (95 % CI 66.3–93.9) effectiveness against Covid-19-related death, 68.4 % (95 % CI 42.3–86.4) against ICU admission, and 55.8 % (95 % CI 42.7–68.3) against hospital admission. ConclusionsOur results show that, despite critical delays in vaccine delivery and limited evidence in efficacy trial estimates, CoronaVac contributed to preventing deaths and severe morbidity due to Covid-19 in elderly adults.

Dynamics of a colloidal particle driven by continuous time-delayed feedback.

We perform feedback experiments and simulations in which a colloidal dumbbell particle, acting as a particle on a ring, is followed by a repulsive optical trap controlled by a continuous-time-delayed feedback protocol. The dynamics are described by a persistent random walk similarly to that of an active Brownian particle, with a transition from predominantly diffusive to driven behavior at a critical delay time. We model the dynamics in the short and long delay regimes using stochastic delay differential equationsand derive a condition for stable driven motion. We study the stochastic thermodynamic properties of the system, finding that the maximum work done by the trap coincides with a local minimum in the mutual information between the trap and the particle position at the onset of stable driven dynamics.

What affects diagnostic and therapeutic times for cancer patients care?

According with "Numbers of cancer in Italy. 2021" mortality is decreasing for both the genders (-10% for men, -8% for women) in Italy. However, this trend is not uniform and seems stable in the Southern regions. Analyses of oncological care in Campania Region highlighted some structural critical issues and delays, which did not guarantee an efficient and effective use of the available economic resources. So, the Campania region established in September 2016 the Campania oncological network (Roc) addressed to prevention, diagnosis, treatment and rehabilitation of tumours through the establishment of multidisciplinary oncological groups (Gom). In February 2020, the ValPeRoc project was launched with the aim of periodically and progressively evaluating the Roc's performance both for the clinical services and for the economic aspects. In five Goms (colon, ovary, lung, prostate, bladder) active in some Roc hospitals, the pre-Gom time elapsing between the date of diagnosis and the date of the first Gom meeting and the Gom time elapsing between the date of the first Gom meeting and the date of the treatment decision were measured. Gom times longer than 28 days were defined as high. The risk of high Gom time was analyzed with a Bart-type machine learning algorithm, considering the set of regressors (features) available to classify patients. The results on the test set (54 patients) report an accuracy of 0.68. The classification technique reported a good fit for colon Gom (93%) and an over-classification for lung Gom. The study of the marginal effects showed a higher risk for those who had a previous therapeutic act and for lung Gom. Within the Goms took in consideration the proposed statistical technique showed that, depending on each Gom, correctly classified about 70% of individuals on risk of delaying permanence within the Roc. The ValPeRoc project evaluates Roc activity for the first time through a replicable analysis of patient pathway times from diagnosis to the act of treatment. Specifically, the times analyzed measure the quality of the regional health care system.

Critical Factors and MitigatingMeasures of Construction Delays of Pakistani Building Construction Projects

The construction industry is a significant contributor to a country's Gross Domestic Product (GDP). However, construction projects often face many issues especially delay. It is a key contributor to project failure, leading to cost overruns and a decline in quality standards. This study aims to identify the critical factors of delay in building construction projects in Pakistan, and its controlling measures of the critical delay factors. A literature review identified 48common factors of delay in the construction industry worldwide. Based on a structured questionnaire and the average index method, 11 critical factors of delays in building construction projects in Pakistan were identified. Furthermore, a semi-structured questionnaire was used to determine 44 possible mitigation measureswhich were extracted from literature review with the 11 critical delay factors. The results of this study will be useful for stakeholders in building construction projects in Pakistan. By incorporating the recommended mitigation measures, they can identify and control the most critical factors that can cause delays in building construction projects. This study contributes to the existing literature by providing a better understanding of the factors causing delays in building construction projects in Pakistan and proposing effective measures to mitigate these factors.

Hopf Bifurcation in a Modified Leslie-Gower Two Preys One Predator Model and Holling Type II Functional Response with Harvesting and Time-Delay

In this paper, a modified Leslie-Gower two preys one predator model and Holling type II functional response with harvesting and time-delay were discussed. Model analysis is carried out by determining fixed points, then analyzing the stability of the fixed points and discussing the existence of the Hopf bifurcation. In some conditions that occur in nature indicate the occurrence of hunting of prey and predator species by humans. Therefore, this model is modified by adding the assumption that prey and predators are being harvested. Another modification given to the model is the use of time delays.The delay time term is for taking into account the case that the members of the predator species need time from birth to predation for being active predators. The first case is a model without time delay, it is obtained that 3 fixed points are unstable and 7 fixed points are stable. One of them is the interior fixed point tested with the Routh-Hurwitz criteria. The second case is a model with a delay time, the critical delay value is obained. Hopf bifurcation occurs when the delay time value is equal to the critical delay value and also fulfills the transversality condition. Observations on the model simulation are carried out by varying the value of the delay time. When the Hopf bifurcation occurs, the graph on the solution plane shows a constant oscillatory movement. If the value of the delay time given is less than the critical value of the delay, the controlled system solution goes to a balanced state. Then when the delay time value is greater than the critical delay value, the system solution continues to fluctuate causing an unstable system condition.

Assessment of most critical project delays on a multi-stage transmission expansion plan using particle swarm optimization

Transmission reinforcement projects of a Transmission Expansion Plan can suffer implementation delays that can impact the short-term power system operation in unpredicted ways. These delays may lead project managers to paying particular care to the development of those plans proved to be most critical from this point of view. This paper proposes a multi-objective dynamic-programming based method to evaluate the impacts of such delays in a short-term transmission plan with respect to load shedding, reliability and losses. It uses the Binary Pareto-Optimal Particle Swarm Optimization as optimization tool. For the trade-off analysis and the final decision to be made, the paper proposes indices to rank the projects in the plan from most to least critical, should they be delayed, based on the severity of the impacts and the probability of occurrence, both on an annual basis and for the whole planning horizon. The proposed method has been tested on an actual Brazilian 40-bus subtransmission system for a 3-year and a 6-year planning horizon, and with the 24-bus IEEE RTS reliability test system for a 3-year planning horizon. To assess its accuracy and efficiency, the results are compared to those using the Non-dominated Sorting Genetic Algorithm II method (NSGA-II) and to the exhaustive search that considers every delay configuration, showing the same accuracy as the exhaustive search and better convergence properties than NSGA-II. The most critical projects are accurately ranked helping the project manager to decide which projects should receive higher attention to guarantee its construction on the planned date. The method obtained a reduction in computational time of 35% for the Brazilian system and of 42% for the IEEE RTS in relation to the exhaustive approach, demonstrating its efficiency.