The role of spore morphology in horizontal transmission of a microsporidium of Daphnia

Parasitology ◽  
2018 ◽  
Vol 145 (11) ◽  
pp. 1452-1457 ◽  
Author(s):  
Hadas Urca ◽  
Frida Ben-Ami
Keyword(s):  
Daphnia Magna ◽  
Horizontal Transmission ◽  
Spore Morphology ◽  
Infection Rates ◽  
Microsporidian Parasite ◽  
Parasite Isolate ◽  
Theoretical Predictions ◽  
Host Mortality ◽  
Host Clone

AbstractThe microsporidian parasite Hamiltosporidium tvaerminnensis can infect Daphnia magna both horizontally (through environmental spores) and vertically (through parthenogenetic and sexually produced eggs). The spores of H. tvaerminnensis come in three distinguishable morphologies, which are thought to have different roles in the transmission of the parasite. In this study, we examined the role of the two most common spore morphologies (i.e. oval-shaped spores and pear-shaped spores) in horizontal transmission of H. tvaerminnensis. To this end, we infected hosts with solutions consisting of either mostly oval- or mostly pear-shaped spores, and quantified infection rates, parasite-induced host mortality and mean number of parasite spores produced per host. We found that spore morphology by itself did not influence infection rates and parasite-induced host mortality. Instead, host clone and parasite isolate interacted with spore morphology in shaping infection outcome and mortality. Thus, there appear to be strong genotype-by-genotype (G × G) interactions in this system. While there is no dispute that H. tvaerminnensis can transmit both vertically and horizontally, our findings do not support theoretical predictions that different spore morphologies hold different roles in horizontal transmission of H. tvaerminnensis.

An Experimental Investigation of Auditors' Liability: Implications for Social Welfare and Exploration of Deviations from Theoretical Predictions

2000 ◽  
Vol 75 (4) ◽  
pp. 429-451 ◽  
Author(s):  
Ronald R. King ◽  
Rachel Schwartz
Keyword(s):  
Experimental Investigation ◽  
Social Welfare ◽  
Strict Liability ◽  
Liability Rule ◽  
Optimal Response ◽  
Legal Regimes ◽  
Theoretical Predictions ◽  
Best Responses

This paper reports the results of an experiment designed to investigate how legal regimes affect social welfare. We investigate four legal regimes, each consisting of a liability rule (strict or negligence) and a damage measure (out-of-pocket or independent-of-investment). The results of the experiment are for the most part consistent with the qualitative predictions of Schwartz's (1997) model; however, subjects' actual choices deviate from the point predictions of the model. We explore whether these deviations arise because: (1) subjects form faulty anticipations of their counterparts' actions and/or (2) subjects do not choose the optimal responses given their anticipations. We find that subjects behave differently under the four regimes in terms of anticipation errors and departures from best responses. For example, subjects playing the role of auditors anticipate investments most accurately under the regime with strict liability combined with out-of-pocket damages, but are least likely to choose the optimal response given their anticipations. This finding implies that noneconomic factors likely play a role in determining subjects' choices.

scholarly journals Spiroplasma Infection among Ixodid Ticks Exhibits Species Dependence and Suggests a Vertical Pattern of Transmission

2021 ◽  
Vol 9 (2) ◽  
pp. 333
Author(s):  
Shohei Ogata ◽  
Wessam Mohamed Ahmed Mohamed ◽  
Kodai Kusakisako ◽  
May June Thu ◽  
Yongjin Qiu ◽  
...  
Keyword(s):  
16S Rdna ◽  
Tick Species ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Horizontal Transmission ◽  
Ixodid Ticks ◽  
Infection Rates ◽  
Transmission Cycle ◽  
Frequent Event ◽  
Pcr Targeting

Members of the genus Spiroplasma are Gram-positive bacteria without cell walls. Some Spiroplasma species can cause disease in arthropods such as bees, whereas others provide their host with resistance to pathogens. Ticks also harbour Spiroplasma, but their role has not been elucidated yet. Here, the infection status and genetic diversity of Spiroplasma in ticks were investigated using samples collected from different geographic regions in Japan. A total of 712 ticks were tested for Spiroplasma infection by PCR targeting 16S rDNA, and Spiroplasma species were genetically characterized based on 16S rDNA, ITS, dnaA, and rpoB gene sequences. A total of 109 samples originating from eight tick species were positive for Spiroplasma infection, with infection rates ranging from 0% to 84% depending on the species. A linear mixed model indicated that tick species was the primary factor associated with Spiroplasma infection. Moreover, certain Spiroplasma alleles that are highly adapted to specific tick species may explain the high infection rates in Ixodes ovatus and Haemaphysalis kitaokai. A comparison of the alleles obtained suggests that horizontal transmission between tick species may not be a frequent event. These findings provide clues to understand the transmission cycle of Spiroplasma species in wild tick populations and their roles in host ticks.

scholarly journals A Stochastic Kinetic Type Reactions Model for COVID-19

Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1221
Author(s):  
Giorgio Sonnino ◽  
Fernando Mora ◽  
Pasquale Nardone
Keyword(s):  
Real Data ◽  
Stochastic Noise ◽  
Mathematical Basis ◽  
Sis Model ◽  
Theoretical Predictions ◽  
Coronavirus Infection ◽  
Massive Distribution ◽  
Second Wave ◽  
Stochastic Sis Model

We propose two stochastic models for the Coronavirus pandemic. The statistical properties of the models, in particular the correlation functions and the probability density functions, were duly computed. Our models take into account the adoption of lockdown measures as well as the crucial role of hospitals and health care institutes. To accomplish this work we adopt a kinetic-type reaction approach where the modelling of the lockdown measures is obtained by introducing a new mathematical basis and the intensity of the stochastic noise is derived by statistical mechanics. We analysed two scenarios: the stochastic SIS-model (Susceptible ⇒ Infectious ⇒ Susceptible) and the stochastic SIS-model integrated with the action of the hospitals; both models take into account the lockdown measures. We show that, for the case of the stochastic SIS-model, once the lockdown measures are removed, the Coronavirus infection will start growing again. However, the combined contributions of lockdown measures with the action of hospitals and health institutes is able to contain and even to dampen the spread of the SARS-CoV-2 epidemic. This result may be used during a period of time when the massive distribution of vaccines in a given population is not yet feasible. We analysed data for USA and France. In the case of USA, we analysed the following situations: USA is subjected to the first wave of infection by Coronavirus and USA is in the second wave of SARS-CoV-2 infection. The agreement between theoretical predictions and real data confirms the validity of our approach.

Prediction of Ball Motion in High-Speed Thrust-Loaded Ball Bearings

1976 ◽  
Vol 98 (3) ◽  
pp. 463-469 ◽  
Author(s):  
C. R. Gentle ◽  
R. J. Boness
Keyword(s):  
Computer Program ◽  
High Speed ◽  
Ball Bearing ◽  
Viscoelastic Behavior ◽  
Specific Situation ◽  
Fluid Models ◽  
Ball Bearings ◽  
Theoretical Predictions ◽  
Ball Motion

This paper describes the development of a computer program used to analyze completely the motion of a ball in a high-speed, thrust-loaded ball bearing. Particular emphasis is paid to the role of the lubricant in governing the forces and moments acting on each ball. Expressions for these forces due to the rolling and sliding of the ball are derived in the light of the latest fluid models, and estimates are also made of the cage forces applicable in this specific situation. It is found that only when lubricant viscoelastic behavior is considered do the theoretical predictions agree with existing experimental evidence.

Role of respiratory heat exchange in production of exercise-induced asthma

1979 ◽  
Vol 46 (3) ◽  
pp. 467-475 ◽  
Author(s):  
E. C. Deal ◽  
E. R. McFadden ◽  
R. H. Ingram ◽  
R. H. Strauss ◽  
J. J. Jaeger
Keyword(s):  
Heat Exchange ◽  
Thermal Load ◽  
Tracheobronchial Tree ◽  
Total Heat Flux ◽  
Random Fashion ◽  
Theoretical Predictions ◽  
Per Se ◽  
Exercise Induced ◽  
Respiratory Heat Exchange

We have hypothesized that it is the total heat flux in the tracheobronchial tree during exercise that determines the degree of postexertional obstruction in asthma, and have developed quanititative expressions that relate these two events. We tested this hypothesis by comparing the observed responses to exercise, while our subjects inhaled dry air at various temperatures ranging from subzero to 80 degrees C in a random fashion, to those that we predicted would occur based upon calculations of respiratory heat exchange. We further determined if heat could be transferred from the inspired air to the mucosa so as to offset evaporative losses from the airways. The observed responses fell as air temperature was increased from -11 to +37 degrees C and exactly matched theoretical predictions. Above 37 degrees C, the observed response exceeded predictions, indicating that it was not possible to provide sufficient heat per se in the air to offset the vaporization of water. However, when small amounts of water vapor were added to the inspirate at high temperatures, bronchospasm was virtually abolished and the response again closely matched theoretical expectations. We conclude that the magnitude of exercise-induced asthma is directly proportional to the thermal load placed on the airways and that this reaction is quantifiable in terms of respiratory heat exchange.

scholarly journals Study of Rare Mesonic Decays Involving Di-Neutrinos in Their Final State

2018 ◽  
Vol 2018 ◽  
pp. 1-20
Author(s):  
Azeem Mir ◽  
Farida Tahir ◽  
Shakeel Mahmood ◽  
Shi- Hai Dong
Keyword(s):  
Branching Fractions ◽  
New Physics ◽  
Supersymmetric Model ◽  
Final State ◽  
Yukawa Couplings ◽  
Leptonic Decays ◽  
Pseudoscalar Mesons ◽  
Theoretical Predictions ◽  
Minimal Supersymmetric Model

We have studied phenomenological implication of R-parity violating (Rp) Minimal Supersymmetric Model (MSSM) via analyses of pure leptonic (M→νν¯) and semileptonic decays of pseudoscalar mesons (M→Xνν¯). These analyses involve comparison between theoretical predictions made by Rp MSSM and the Standard Model (SM) with the experimental results like branching fractions (Br) of the said process. We have found, in general, that Rp contribution dominates over the SM contribution, i.e., by a factor of 10 for the pure leptonic decays of KL,S and by 102 and 104 in case of Bs and Bd, respectively. Furthermore, the limits obtained on Rp Yukawa couplings (λαkβ′λαkγ′⁎) by using Br  (M→Xνν¯) are used to calculate Br  (M→νν¯). This demonstrates the role of Rp MSSM as a viable model for the study of new physics contribution in rare decays at places like Super B factories, KOTO (J-PARC) and NA62 at CERN.

Ectomycorrhizae in the Agaricales and Gasteromycetes

1983 ◽  
Vol 61 (3) ◽  
pp. 909-916 ◽  
Author(s):  
Orson K. Miller Jr.
Keyword(s):  
Fruiting Body ◽  
Biological Role ◽  
Spore Morphology ◽  
Generic Level ◽  
Body Form ◽  
Ecological Conditions ◽  
Fungal Succession ◽  
The Past ◽  
Made In

Over the past decade much progress has been made in an effort to determine which fungi are mycorrhizal symbionts. It is now apparent that one ectomycorrhizal or ectendomycorrhizal host is often able to form mycorrhizae with a wide variety of higher fungi. Evidence is presented which supports the hypothesis that fungal succession occurs as the host matures. In addition, fungi which are normally ectomycorrhizal may sometimes form endomycorrhizae on different hosts or under altered ecological conditions. There has also been much evolution in fruiting-body form and mode of spore discharge especially under severe montane or desert conditions. As a result patterns are emerging in the Homobasidiomycetes at the order, family, and generic level in the evolution of the mycorrhizal habit. Spore morphology, habitat, and distribution are listed and discussed in relation to the biological role of the fungi.

scholarly journals Retrospective Study on Personal Protective Equipment During Pandemic Link to Outbreak of Carbpenem-Resistant Enterobacteriace

2021 ◽  
Vol 1 (S1) ◽  
pp. s9-s10
Author(s):  
Kenisha Evans ◽  
Jennifer LeRose ◽  
Angela Beatriz Cruz ◽  
Lavina Jabbo ◽  
Teena Chopra
Keyword(s):  
Retrospective Study ◽  
Infection Control ◽  
Personal Protective Equipment ◽  
Horizontal Transmission ◽  
Control Measures ◽  
Protective Equipment ◽  
Local Health ◽  
Infection Rates ◽  
Infection Control Measures ◽  
The Impact

Background: In 2019, according to the Centers for Disease Control and Prevention, carbapenem-resistant Enterobacteriaceae (CRE), had cost the lives of >35,000 patients, particularly the most virulent plasmid-mediated New Delhi metallo-β-lactamase (NDM). Although healthcare systems normally have strict surveillance and infection control measures for CRE, the rapid emergence of novel SAR-CoV-2 and COVID-19 led to a shortage of personal protective equipment (PPE) and medical supplies. As a result, routine infection practices, such as contact precautions, were violated. Studies have shown this depletion and shift in resources compromised the control of infections such CRE leading to rising horizontal transmission. Method: A retrospective study was conducted at a tertiary healthcare system in Detroit, Michigan, to determine the impact of PPE shortages during the COVID-19 pandemic on NDM infection rates. The following periods were established during 2020 based on PPE availability: (1) pre-PPE shortage (January–June), (2) PPE shortage (July–October), and (3) post-PPE shortage (November–December). Rates of NDM per 10,000 patient days were compared between periods using the Wilcoxon signed rank-sum test. Isolates were confirmed resistant by NDM by molecular typing performed by the Michigan State Health Department. Patient characteristics were gathered by medical chart review and patient interviews by telephone. Results: Overall, the average rate of NDM infections was 1.82 ±1.5 per 10,000 patient days. Rates during the PPE shortage were significantly higher, averaging 3.6 ±1.1 cases per 10,000 patient days (P = .02). During this time, several infections occurred within patients on the same unit and/or patients with same treating team, suggesting possible horizontal transmission. Once PPE stock was replenished and isolation practices were reinstated, NDM infection rates decreased to 0.77 ±1.1 per 10,000 patient days. Conclusion: Control of CRE requires strategic planning with active surveillance, antimicrobial constructs, and infection control measures. The study illustrates that in times of crisis, such as the COVID-19 pandemic, the burden of effective infection control requires much more multidisciplinary efforts to prevent unintentional lapses in patient safety. A swift response by the state and local health departments at a tertiary-care healthcare center conveyed a positive mitigation of the highest clinical threats and decreased horizontal transmission of disease.Funding: NoDisclosures: None

scholarly journals Indirectness in the Age of Globalization: A Social Network Analysis

2019 ◽  
Vol 23 (4) ◽  
pp. 930-949
Author(s):  
Marina Terkourafi
Keyword(s):  
African American ◽  
American English ◽  
Historical Context ◽  
Theory Building ◽  
Network Ties ◽  
British English ◽  
Theoretical Predictions ◽  
The Individual ◽  
Individual Self

Indirectness has traditionally been viewed as commensurate with politeness and attributed to the speaker’s wish to avoid imposition and/or otherwise strategically manipulate the addressee. Despite these theoretical predictions, a number of studies have documented the solidarity-building and identity-constituting functions of indirectness. Bringing these studies together, Terkourafi 2014 proposed an expanded view of the functions of indirect speech, which crucially emphasizes the role of the addressee and the importance of network ties. This article focuses on what happens when such network ties become loosened, as a result of processes of urbanization and globalization. Drawing on examples from African American English and Chinese, it is argued that these processes produce a need for increased explicitness, which drives speakers (and listeners) away from indirectness. This claim is further supported diachronically, by changes in British English politeness that coincide with the rise of the individual Self. These empirical findings have implications for im/politeness theorizing and theory-building more generally, calling attention to how the socio-historical context of our research necessarily influences the theories we end up building.

scholarly journals Role of Spin in NN → NNπ

2016 ◽  
Vol 40 ◽  
pp. 1660061
Author(s):  
Vadim Baru
Keyword(s):  
Partial Wave ◽  
Pion Production ◽  
Low Energy ◽  
Partial Wave Analysis ◽  
P Wave ◽  
Wave Analysis ◽  
Theoretical Predictions

The recent measurements of the reactions [Formula: see text] and [Formula: see text] by the ANKE collaboration at COSY are analyzed with the focus on the p-wave pion production amplitudes. These amplitudes are known to provide an important connection between [Formula: see text] and other low-energy few-nucleon reactions. The results of the recent partial wave analysis of the ANKE data are discussed and compared with the theoretical predictions.

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