Discontinuous epidemic transition due to limited testing.
Ontology highlight
ABSTRACT:
SUBMITTER: Scarselli D
PROVIDER: S-EPMC8110767 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The structure and design of optimal supply networks is an important topic in complex networks research. A fundamental trait of natural and man-made networks is the emergence of loops and the trade-off governing their formation: adding redundant edges to supply networks is costly, yet beneficial for resilience. Loops typically form when costs for new edges are small or inputs uncertain. Here, we shed further light on the transition to loop formation. We demonstrate that loops emerge discontinuously when decreasing the costs for new edges for both an edge-damage model and a fluctuating sink model. Mathematically, new loops are shown to form through a saddle-node bifurcation. Our analysis allows to heuristically predict the location and cost where the first loop emerges. Finally, we unveil an intimate relationship among betweenness measures and optimal tree networks. Our results can be used to understand the evolution of loop formation in real-world biological networks.
| S-EPMC7670464 | biostudies-literature
Project description:In purely repulsive colloidal systems a glass transition can be reached by increasing the particle volume fraction beyond a certain threshold. The resulting glassy state is governed by configurational cages which confine particles and restrict their motion. A colloidal glass may also be formed by inducing attractive interactions between the particles. When attraction is turned on in a repulsive colloidal glass a re-entrant solidification ensues. Initially, the repulsive glass melts as free volume in the system increases. As the attraction strength is increased further, this weakened configurational glass gives way to an attractive glass in which motion is hindered by the formation of physical bonds between neighboring particles. In this paper, we study the transition from repulsive-to-attractive glasses using three-dimensional imaging at the single-particle level. We show how the onset of cage weakening and bond formation is signalled by subtle changes in local structure. We then demonstrate the discontinuous nature of the solid-solid transition, which is marked by a critical onset at a threshold bonding energy. Finally, we highlight how the interplay between bonding and caging leads to complex and heterogeneous dynamics at the microscale.
| S-EPMC4778135 | biostudies-other
Project description:The accurate grading of malignant astrocytomas has significant prognostic and therapeutic implications. Traditional histopathological grading can be challenging due to regional tumor heterogeneity, especially in scenarios where small amounts of tissue are available for pathologic review. Here, we hypothesized that a critical tumor resection volume is needed for correct grading of astrocytomas by histopathology. For insufficient tissue sampling, IDH1 molecular testing can act as a complementary marker to improve diagnostic accuracy. Volumetric analyses were obtained using preoperative and postoperative MRI images. Histological specimens were gathered from 403 patients with malignant astrocytoma who underwent craniotomy. IDH1 status was assessed by immunohistochemistry and sequencing. Patients with >20 cubic centimeters (cc) of the total tumor volume resected on MRI have higher rate of GBM diagnosis compared to <20 cc [odds ratio (OR) 2.57, 95% confidence interval (CI) 1.6-4.06, P < 0.0001]. The rate of IDH1 status remained constant regardless of the tumor volume resected (OR 0.81, 95% CI 0.48-1.36, P < 0.43). The rate of GBM diagnosis is twofold greater for individual surgical specimen >10 cc than those of lower volume (OR 2.48, 95% CI 1.88-3.28, P < 0.0001). Overall survival for AA patients with >20 cc tumor resection on MRI is significantly better than those with <20 cc tumor resected (P < 0.05). No volume-dependent differences were observed in patients with GBM (P < 0.4), IDH1 wild type (P < 0.1) or IDH1 mutation (P < 0.88). IDH1 status should be considered when total resection volume is <20 cc based on MRI analysis and for surgical specimen <10 cc to complement histopathologic diagnosis of malignant astrocytomas. In these specimens, under-diagnosis of GBM may occur when analysis is restricted to histopathology alone.
| S-EPMC4386582 | biostudies-literature
Project description:The process by which sheared suspensions go through a dramatic change in viscosity is known as discontinuous shear thickening. Although well-characterized on the macroscale, the microscopic mechanisms at play in this transition are still poorly understood. Here, by developing new experimental procedures based on quartz-tuning fork atomic force microscopy, we measure the pairwise frictional profile between approaching pairs of polyvinyl chloride and cornstarch particles in solvent. We report a clear transition from a low-friction regime, where pairs of particles support a finite normal load, while interacting purely hydrodynamically, to a high-friction regime characterized by hard repulsive contact between the particles and sliding friction. Critically, we show that the normal stress needed to enter the frictional regime at nanoscale matches the critical stress at which shear thickening occurs for macroscopic suspensions. Our experiments bridge nano and macroscales and provide long needed demonstration of the role of frictional forces in discontinuous shear thickening.
| S-EPMC5499204 | biostudies-literature
Project description:Coronaviruses contain a positive-sense single-stranded genomic (g) RNA, which encodes nonstructural proteins. Several subgenomic mRNAs (sgmRNAs) encoding structural proteins are generated by template switching from the body transcription regulatory sequence (TRS) to the leader TRS. The process preferentially generates shorter sgmRNA. Appropriate readthrough of body TRSs is required to produce longer sgmRNAs and full-length gRNA. We find that phosphorylation of the viral nucleocapsid (N) by host glycogen synthase kinase-3 (GSK-3) is required for template switching. GSK-3 inhibition selectively reduces the generation of gRNA and longer sgmRNAs, but not shorter sgmRNAs. N phosphorylation allows recruitment of the RNA helicase DDX1 to the phosphorylated-N-containing complex, which facilitates template readthrough and enables longer sgmRNA synthesis. DDX1 knockdown or loss of helicase activity markedly reduces the levels of longer sgmRNAs. Thus, coronaviruses employ a unique strategy for the transition from discontinuous to continuous transcription to ensure balanced sgmRNAs and full-length gRNA synthesis.
| S-EPMC7104987 | biostudies-literature
Project description:Childhood obesity is now recognized as a global public health issue. Social patterning of obesity, consistent with the theory of epidemiologic transition, has not been well described in children, and the limited research has focused on developed settings. The aim of this study was to describe the relationship between childhood obesity and household income using objective measures of adiposity and to explore how this relationship differs across levels of country human development.The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) was a multi-national cross-sectional study conducted in 12 urban/suburban study sites that represented all inhabited continents and wide ranges of development. ISCOLE collected objectively measured height, body mass and percentage body fat in 7341 10-year-old children. Multi-level random-effects models were used to examine income gradients in several obesity measures.The mean age of the children was 10.4 years, and 12.6% were obese, ranging from 5.4% (Finland) to 23.8% (China). For both boys and girls, obesity prevalence, body fat percentage and body mass index (BMI) z-score increased linearly with higher income at lower levels of development (all P for trend ⩽0.0012), but decreased linearly with higher income at higher levels of development (all P for trend ⩽0.0003). Country human development explained 75% of the variation in the country-specific income-obesity relationships (r=-0.87, P=0.0003).Results are consistent with the theory of epidemiologic transition. Global efforts to control obesity must account for socioeconomic factors within a country's context. Future research should seek to understand global socioeconomic patterns in obesity-related lifestyle behaviors.
| S-EPMC4850613 | biostudies-other
Project description:Outbreaks of infectious diseases, such as influenza, are a major societal burden. Mitigation policies during an outbreak or pandemic are guided by the analysis of data of ongoing or preceding epidemics. The reproduction number, R0, defined as the expected number of secondary infections arising from a single individual in a population of susceptibles is critical to epidemiology. For typical compartmental models such as the Susceptible-Infected-Recovered (SIR) R0 represents the severity of an epidemic. It is an estimate of the early-stage growth rate of an epidemic and is an important threshold parameter used to gain insights into the spread or decay of an outbreak. Models typically use incidence counts as indicators of cases within a single large population; however, epidemic data are the result of a hierarchical aggregation, where incidence counts from spatially separated monitoring sites (or sub-regions) are pooled and used to infer R0. Is this aggregation approach valid when the epidemic has different dynamics across the regions monitored? We characterize bias in the estimation of R0 from a merged data set when the epidemics of the sub-regions, used in the merger, exhibit delays in onset. We propose a method to mitigate this bias, and study its efficacy on synthetic data as well as real-world influenza and COVID-19 data.
| S-EPMC8375253 | biostudies-literature
Project description:Empirical data collected over the past two decades have demonstrated strong links between low literacy skills and poor health outcomes, including mortality. Recently, the Educational Testing Service released a relevant report predicting that our nation is at great risk as a result of declining adult literacy, shifting demographics, and a changing economy. It is essential to understand how these educational and socioeconomic changes will impact health care and prepare for a likely epidemic of limited health literacy. A formative public health response should include seeking out new strategies for health systems to advance our public's health literacy, while working with the educational system to better equip younger generations with the knowledge and skills necessary to navigate health care.
| S-EPMC2517979 | biostudies-other
Project description:The global prevalence of obesity has increased substantially over the past 40 years, from less than 1% in 1975, to 6-8% in 2016, among girls and boys, and from 3% to 11% among men and from 6% to 15% among women over the same time period. Our aim was to consolidate the evidence on the epidemiology of obesity into a conceptual model of the so-called obesity transition. We used illustrative examples from the 30 most populous countries, representing 77·5% of the world's population to propose a four stage model. Stage 1 of the obesity transition is characterised by a higher prevalence of obesity in women than in men, in those with higher socioeconomic status than in those with lower socioeconomic status, and in adults than in children. Many countries in south Asia and sub-Saharan Africa are presently in this stage. In countries in stage 2 of the transition, there has been a large increase in the prevalence among adults, a smaller increase among children, and a narrowing of the gap between sexes and in socioeconomic differences among women. Many Latin American and Middle Eastern countries are presently at this stage. High-income east Asian countries are also at this stage, albeit with a much lower prevalence of obesity. In stage 3 of the transition, the prevalence of obesity among those with lower socioeconomic status surpasses that of those with higher socioeconomic status, and plateaus in prevalence can be observed in women with high socioeconomic status and in children. Most European countries are presently at this stage. There are too few signs of countries entering into the proposed fourth stage of the transition, during which obesity prevalence declines, to establish demographic patterns. This conceptual model is intended to provide guidance to researchers and policy makers in identifying the current stage of the obesity transition in a population, anticipating subpopulations that will develop obesity in the future, and enacting proactive measures to attenuate the transition, taking into consideration local contextual factors.
| S-EPMC7360432 | biostudies-literature
Project description:Arteri-, corona-, toro- and roniviruses are evolutionarily related positive-strand RNA viruses, united in the order Nidovirales. The best studied nidoviruses, the corona- and arteriviruses, employ a unique transcription mechanism, which involves discontinuous RNA synthesis, a process resembling similarity-assisted copy-choice RNA recombination. During infection, multiple subgenomic (sg) mRNAs are transcribed from a mirror set of sg negative-strand RNA templates. The sg mRNAs all possess a short 5' common leader sequence, derived from the 5' end of the genomic RNA. The joining of the non-contiguous 'leader' and 'body' sequences presumably occurs during minus-strand synthesis. To study whether toroviruses use a similar transcription mechanism, we characterized the 5' termini of the genome and the four sg mRNAs of Berne virus (BEV). We show that BEV mRNAs 3-5 lack a leader sequence. Surprisingly, however, RNA 2 does contain a leader, identical to the 5'-terminal 18 residues of the genome. Apparently, BEV combines discontinuous and non-discontinuous RNA synthesis to produce its sg mRNAs. Our findings have important implications for the understanding of the mechanism and evolution of nidovirus transcription.
| S-EPMC136939 | biostudies-literature