Spill Back Research Articles

Suitability of invasive gobies as paratenic hosts for acanthocephalans of the genus Pomphorhynchus sp.

Abstract Ponto-Caspian gobies became highly abundant in many regions outside their native distribution range (e.g. in the Rhine River system). In the newly invaded habitats, the parasite communities of the invasive gobies are characterized by a lower species richness compared to their native range. Interestingly, acanthocephalans of the genus Pomphorhynchus are highly abundant, although they do not become mature and mostly remain encapsulated in the abdominal cavity as preadults. Thus, gobiids could either represent a dead-end host for Pomphorhynchus sp. declining its population (dilution effect) or act as a paratenic host that could increase the infection pressure if the infected gobies are preyed upon by appropriate definitive hosts (spill back). To determine which of the 2 scenarios the gobiids contribute to, we conducted 2 infection experiments using smaller and larger individuals of the definitive host chub (Squalius cephalus), infected with preadults of Pomphorhynchus sp. collected from the abdominal cavity of Neogobius melanostomus. The results showed that preadults were able to complete their development and mature in the definitive host with mean recovery rates of 17.9% in smaller and 27.0% in larger chubs. Successful infections were observed in 62.0% and 80.0% of the smaller and larger chubs, respectively. Our study demonstrated that gobies can theoretically serve as a paratenic host for acanthocephalans of the genus Pomphorhynchus, and that infection might spill back into the local fish community if infected gobies are preyed upon by suitable definitive hosts of Pomphorhynchus sp. such as large barbel or chub.

Dependence of the Spill Back Effect on the Energy Level Distribution of Interface States Under the Transfer Gate in CMOS Image Sensor

Dependence of the Spill Back Effect on the Energy Level Distribution of Interface States Under the Transfer Gate in CMOS Image Sensor

Endocytosis inhibitors block SARS-CoV-2 pseudoparticle infection of mink lung epithelium.

Both spill over and spill back of SARS-CoV-2 virus have been reported on mink farms in Europe and the United States. Zoonosis is a public health concern as dangerous mutated forms of the virus could be introduced into the human population through spillback. The purpose of our study was to determine the SARS-CoV-2 entry mechanism using the mink lung epithelial cell line (Mv1Lu) and to block entry with drug inhibitors. Mv1Lu cells were susceptible to SARS-CoV-2 viral pseudoparticle infection, validating them as a suitable disease model for COVID-19. Inhibitors of TMPRSS2 and of endocytosis, two pathways of viral entry, were tested to identify those that blocked infection. TMPRSS2 inhibitors had minimal impact, which can be explained by the apparent lack of activity of this enzyme in the mink and its localization within the cell, not on the cell surface. Dyngo4a, a small molecule endocytosis inhibitor, significantly reduced infection, supporting the conclusion that the entry of the SARS-CoV-2 virus into Mv1Lu cells occurs primarily through endocytosis. The small molecule inhibitors that were effective in this study could potentially be used therapeutically to prevent SARS-CoV-2 infection in mink populations. This study will facilitate the development of therapeutics to prevent zoonotic transmission of SARS-CoV-2 variants to other animals, including humans.

The hazard of carbapenemase (OXA-181)-producing Escherichia coli spreading in pig and veal calf holdings in Italy in the genomics era: Risk of spill over and spill back between humans and animals.

Carbapenemase-producing Enterobacterales (CPE) are considered a major public health issue. In the frame of the EU Harmonized AMR Monitoring program conducted in Italy in 2021, 21 epidemiological units of fattening pigs (6.98%; 95% CI 4.37-10.47%; 21/301) and four epidemiological units of bovines <12 months (1.29%; 95% CI 0.35-3.27%, 4/310) resulted positive to OXA-48-like-producing E. coli (n = 24 OXA-181, n = 1 OXA-48). Whole Genome Sequencing (WGS) for in-depth characterization, genomics and cluster analysis of OXA-181-(and one OXA-48) producing E. coli isolated, was performed. Tracing-back activities at: (a) the fattening holding of origin of one positive slaughter batch, (b) the breeding holding, and (c) one epidemiologically related dairy cattle holding, allowed detection of OXA-48-like-producing E. coli in different units and comparison of further human isolates from fecal samples of farm workers. The OXA-181-producing isolates were multidrug resistant (MDR), belonged to different Sequence Types (STs), harbored the IncX and IncF plasmid replicons and multiple virulence genes. Bioinformatics analysis of combined Oxford Nanopore Technologies (ONT) long reads and Illumina short reads identified bla OXA-181 as part of a transposon in IncX1, IncX3, and IncFII fully resolved plasmids from 16 selected E. coli, mostly belonging to ST5229, isolated during the survey at slaughter and tracing-back activities. Although human source could be the most likely cause for the introduction of the bla OXA-181-carrying IncX1 plasmid in the breeding holding, concerns arise from carbapenemase OXA-48-like-producing E. coli spreading in 2021 in Italian fattening pigs and, to a lesser extent, in veal calf holdings.

Ecological processes underlying the emergence of novel enzootic cycles: Arboviruses in the neotropics as a case study.

Pathogens originating from wildlife (zoonoses) pose a significant public health burden, comprising the majority of emerging infectious diseases. Efforts to control and prevent zoonotic disease have traditionally focused on animal-to-human transmission, or “spillover.” However, in the modern era, increasing international mobility and commerce facilitate the spread of infected humans, nonhuman animals (hereafter animals), and their products worldwide, thereby increasing the risk that zoonoses will be introduced to new geographic areas. Imported zoonoses can potentially “spill back” to infect local wildlife—a danger magnified by urbanization and other anthropogenic pressures that increase contacts between human and wildlife populations. In this way, humans can function as vectors, dispersing zoonoses from their ancestral enzootic systems to establish reservoirs elsewhere in novel animal host populations. Once established, these enzootic cycles are largely unassailable by standard control measures and have the potential to feed human epidemics. Understanding when and why translocated zoonoses establish novel enzootic cycles requires disentangling ecologically complex and stochastic interactions between the zoonosis, the human population, and the natural ecosystem. In this Review, we address this challenge by delineating potential ecological mechanisms affecting each stage of enzootic establishment—wildlife exposure, enzootic infection, and persistence—applying existing ecological concepts from epidemiology, invasion biology, and population ecology. We ground our discussion in the neotropics, where four arthropod-borne viruses (arboviruses) of zoonotic origin—yellow fever, dengue, chikungunya, and Zika viruses—have separately been introduced into the human population. This paper is a step towards developing a framework for predicting and preventing novel enzootic cycles in the face of zoonotic translocations.

Analysis and Modeling of Spill Back Effect in High Illumination CMOS Image Sensors

To improve charge transfer efficiency ( CTE ) and eliminate image lag, the impact of spill back effect on image lag is studied in CMOS image sensors (CISs), particularly in high illumination condition. By establishing a mathematical model based on the thermionic emission and drift-diffusion theory, the physical mechanism of spill back effect is described. This model shows that a lower transfer gate (TG) operating voltage and a higher reset voltage of Floating Diffusion (FD) node would mitigate spill back effect. In a $0.18\mu \text{m}$ CMOS process, by setting that the gate voltage of transfer transistor and the reset voltage of FD is 2.8 V and 3.8 V respectively, CTE of the proposed pixel is increased to 100%. The theoretical analysis and TCAD simulation results can explain spill back effect and offer a reference for designing a high CTE pixel in high illumination CISs.

Dissipation and dynamics in ultrafast intersystem crossings.

The effects of dynamics and dissipation on ultrafast intersystem crossings are studied for a dissipative two-level system coupled to a local vibronic mode. A method of amplitude damping of the wave packet is presented that accounts better for the position of the wave packet and avoids spurious transitions between potential wells. It is demonstrated that Fermi's golden rule, the typical semiquantitative approach to extract population transfer rates from potential landscapes, only holds under limited conditions. Generally, the effects of dynamics and dissipation lead to deviations from the expected exponential population transfer, strong changes in transfer times and total population transfer, and significant recurrence or "spill back" of the wave packet.

How Ponto-Caspian invaders affect local parasite communities of native fish.

Invasive species are a major threat to ecosystems worldwide. Their effects are versatile and mostly well studied. However, not much is known about the impact of invasion on native parasite communities, although parasites are usually important response variables for ecosystem health. To improve the knowledge on how native fish parasite communities and their dynamics are affected by invasive species and how these processes change local host-parasite interactions over time, we studied different host-parasite systems in four German rivers. Three of these rivers (Rhine, Ems, and Elbe) are heavily invaded by different Ponto-Caspian species such as the amphipod Dikerogammarus villosus and various gobiids such as Neogobius melanostomus and Ponticola kessleri that serve as potential hosts for different local parasite species, while the fourth river (Schwentine) was free of any Ponto-Caspian invaders. Due to the lack of additional uninvaded river systems, literature data on parasite communities before invasion were compared with the post invasion status for the rivers Rhine and Elbe. The results showed differences among the parasite communities of different host species from the three invaded rivers when compared to the Schwentine River. Among the local internal parasite communities, especially the acanthocephalan Pomphorhynchus laevis and the nematode Raphidascaris acus have to be considered as key species associated with invasions from the Ponto-Caspian region. As the examined invasive Ponto-Caspian fish species serves as suitable host for both parasite species, the increases in their infection rates in native fish species are examples of parasite spill back (R. acus) and spill over (P. laevis, at least in the river Rhine). These results were further supported by the analysis of literature data on parasite communities of the past 20years. Consequences for local parasite communities range from decreased prevalence of native parasites towards an extinction of entire parasite species.

Evaluating National Park entrance station queues: A case study in Grand Teton National Park

In this study, two park entrance stations to the Moose-Wilson Corridor in Grand Teton National Park (GRTE) were examined. The Granite Canyon entrance station along with the proposed Moose entrance station were evaluated for queueing measures of performance in present and for future conditions. Methods of evaluation included the applications of Little’s Law and simulation modeling. It was determined that a similar service rate of 25 s can be anticipated for both considered queueing stations, resulting in a capacity of 144 vehicles per hour. Both systems, were sensitive to increases of arrival and service rates greater than 100 vehicles per hour and 35 s, respectively. A minimum 47.1-meter (154 ft) distance from the downstream intersection was estimated as a conservative minimum length for the proposed Moose entrance station to avoid queue spill back. The results of this study provided information to the future planning and design of GRTE’s Moose queueing station. Additionally, this study provides a guide for data collection as well as the use of queueing theory methodology to gain an understanding of a queueing setting, quantifying observations and the development and computation of data to assist in a policy decision making process. Therefore, this study presents a case where queueing theory methodology was used to generate information and emphasizes how queueing effects can be considered for policy changes in a National Park.

Urban Storage Space Selection Method for Integrated Control on a Freeway Bottleneck

Ramp metering is an effective means to reduce freeway bottleneck delay that results from the capacity drop phenomenon when congestion sets in. The bottleneck flow is kept at free-flow capacity by temporarily storing vehicles traveling toward the bottleneck at the ramp. The metering duration is normally limited because of the finite amount of ramp storage space available to prevent undesired spill back to the urban network. A beneficial extension of the metering duration might be achieved by strategically choosing upstream intersection arms that reduce their inflow to the ramp. For that purpose, coordination needs to be realized between the ramp meter and its intersection controllers located upstream, which will also hinder vehicles not traveling toward the ramp. In this contribution, an evaluation approach is put forward to decide objectively which intersection buffers (arms) should be included in the coordination. To quantify the resulting delays in the system, cumulative inflow and outflow curves are developed as a function of the involved situation-specific variables. This approach enables one to determine the optimal set of coordinated buffers beforehand and to gain insight into the effect of the various system variables on the delays. By means of worked examples, these effects are illustrated, and the way to determine the optimal set of coordinated buffers is shown. Results show that the length of the peak period and the size of the capacity drop strongly determine the coordination benefits, and, hence, a buffer’s minimum required fraction of traffic traveling past the bottleneck needed to result in beneficial coordination.

Adventures in Hybrid Space

Abstract: Digital technologies offer performance artists remarkable new tools and unique perspectives for creating and presenting work. In a world increasingly mediated by digital devices, new innovations are driving us toward more and more immersive experiences. Artists are pioneering new technologies, questioning and pressing against the boundaries of these synthetic environments and using the Internet to reach around the world to connect with other artists and new audiences. With the emergence of augmented-reality technology, virtual reality is now bursting at the seams and about to spill back out into the world. The overlay of the virtual onto the real is becoming more commonplace, and artists are poised to not only navigate these new technologies but also locate and push past new boundaries.

Analysis of fixed-time control

The paper presents an analysis of the traffic dynamics in a network of signalized intersections. The intersections are regulated by fixed-time (FT) controls, all with the same cycle length or period, T. The network is modeled as a queuing network. Vehicles arrive from outside the network at entry links in a deterministic periodic stream, also with period T. They take a fixed time to travel along each link, and at the end of the link they join a queue. There is a separate queue at each link for each movement or phase. Vehicles make turns at intersections in fixed proportions, and eventually leave the network, that is, a fraction r(i,j) of vehicles that leave queue i go to queue j and the fraction [1-∑jr(i,j)] leave the network. The storage capacity of the queues is infinite, so there is no spill back. The main contribution of the paper is to show that if the signal controls accommodate the demands then, starting in any initial condition, the network state converges to a unique periodic orbit. Thus, the effect of initial conditions disappears. More precisely, the state of the network at time t is the vector x(t) of all queue lengths, together with the position of vehicles traveling along the links. Suppose that the network is stable, that is, x(t) is bounded. Then(1)there exists a unique periodic trajectory x∗, with period T;(2)every trajectory converges to this periodic trajectory;(3)if vehicles do not follow loops, the convergence occurs in finite time.The periodic trajectory determines the performance of the entire network.

Isolation and molecular characterization of Mycobacterium tuberculosis from humans and cattle in Namwala District, Zambia.

Mycobacterium tuberculosis, the causative agent of tuberculosis in humans, is considered primarily a human pathogen. It has, however, been reported in a wide range of domestic and wild animals, often living in close prolonged contact with humans. Sputum samples in which acid fast bacteria were detected in smears were collected from patients at three health facilities in Namwala district, Zambia. Samples from cattle presenting gross lesions compatible with bovine tuberculosis were collected at a local abattoir in the same district. Isolated mycobacteria were identified and genotyped using classical molecular methods. From a total of 33 isolates of M. tuberculosis detected (30 from humans and 3 from cattle), two cattle isolates shared the same spoligotype and MIRU-VNTR pattern with a human patient. This study has for the first time documented the isolation of M. tuberculosis from cattle in Zambia and provides molecular evidence of an epidemiological link between M. tuberculosis isolates from humans and cattle in Namwala district. A possible spill back of M. tuberculosis to humans cannot be excluded and therefore further studies documenting to what extent M. tuberculosis is shed in cattle milk are needed. This finding further suggests that veterinary public health measures to control human TB, should also take into account the bovine reservoir.

Dynamic Behaviour CO2 Capture and Compression: An Assessment

A clear understanding of the dynamic behavior of the whole chain of conventional power generation to CO2 storage is necessary. The rapidly increasing share of renewable energy makes the energy delivered to the grid more fluctuating leading to an impact on the CCS chain as well. A 250 MW scale carbon capture plant with CO2 compression has been modelled with Dymola (dynamic) and with Aspen Plus (steady-state). It is evident that large perturbations in flue gas flow rate will make it difficult to control the water balance. Moreover, parallel compression trains may be necessary to prevent compressors to run in spill back mode.

Formation and Propagation of Local Traffic Jam

Large scale traffic congestion often stems from local traffic jam in single road or intersection. In this paper, macroscopic method was used to explore the formation and propagation of local traffic jam. It is found that (1) the propagation of traffic jam can be seen as the propagation of traffic signal parameters, that is, virtual split and virtual green time; (2) for a road with endogenous flow, entrance location influences the jam propagation. With the same demand (upstream links flow and entrance flow), the upstream got more influence; (3) when a one-lane road is thoroughly congested, virtual signal parameters everywhere are the same as that at stop line; for a basic road, the virtual signals work in a cooperative manner; (4) phase sequence is one important parameter that influences traffic performances during peak hour where spill back of channelization takes place. The same phase plan for left-turn flow and through flow would be preferred; (5) signal coordination plays an important role in traffic jam propagation and hence effective network signal parameters should be designed to prevent jam from propagation to the whole network. These findings would serve as a basis for future network traffic congestion control.

Changes in parasitoid communities over time and space: a historical case study of the maize pest Ostrinia nubilalis.

Understanding the ways in which human environmental modifications affect biodiversity is a key challenge in conservation planning, pest control and evolutionary ecology. Parasitoid communities, particularly those associated with agricultural pests, may be susceptible to such modifications. We document here changes in the larval parasitoid communities of Ostrinia nubilalis — the main pest of maize — and its sibling species O. scapulalis, based on two historical datasets, one collected from 1921–1928 and the other from 2001–2005. Each of these datasets encompasses several years and large geographical areas and was based on several thousands/millions of host larvae. The 80-year interval between the two datasets was marked by a decrease in O. nubilalis parasitism to about two thirds its initial level, mostly due to a decrease in the rate of parasitism by hymenopterans. However, a well balanced loss and gain of species ensured that species richness remained stable. Conversely, O. scapulalis displayed stable rates of parasitism over this period, with a decline in the species richness of its parasitoid community. Rates of parasitism and species richness in regions colonized by O. nubilalis during the 1950s were one half to one third those in regions displaying long-term colonisation by this pest. During the recent human activity-driven expansion of its range, O. nubilalis has neither captured native parasitoids nor triggered parasite spill back or spill over.

Implementing the maximum likelihood methodology to measure a driver’s critical gap

Most of the capacity calculation procedures for two-way stop-controlled (TWSC) intersections are based on gap acceptance models. Critical gap is one of the major parameters for gap acceptance models. The accuracy of capacity estimation is mainly determined by the accuracy of the critical gap. This paper focuses on the implementation of the maximum likelihood technique to measure a driver’s critical gap using field data. A methodology to define gap events is proposed, so that the accepted gaps and maximum rejected gaps required by the maximum likelihood technique could be obtained. Specific issues regarding multi-lane situations and major street right turn movement are discussed. Special conditions observed during the research are addressed when the proposed method cannot be applied directly, such as the existence of a mid-block refuge area where minor street drivers can seek gaps in a two-stage process, pedestrian blockage, and downstream queue spill back. The proposed method was adopted in measuring critical gap under US conditions during a research project, described by Kyte et al. (1996). ©