117 research outputs found

    Bubble collisions and measures of the multiverse

    Full text link
    To compute the spectrum of bubble collisions seen by an observer in an eternally-inflating multiverse, one must choose a measure over the diverging spacetime volume, including choosing an "initial" hypersurface below which there are no bubble nucleations. Previous calculations focused on the case where the initial hypersurface is pushed arbitrarily deep into the past. Interestingly, the observed spectrum depends on the orientation of the initial hypersurface, however one's ability observe the effect rapidly decreases with the ratio of inflationary Hubble rates inside and outside one's bubble. We investigate whether this conclusion might be avoided under more general circumstances, in particular placing the observer's bubble near the initial hypersurface. We find that it is not. As a point of reference, a substantial appendix reviews relevant aspects of the measure problem of eternal inflation.Comment: 24 pages, two figures, plus 16-page appendix with one figure; v2: minor improvements and clarifications, conclusions unchanged (version to appear in JCAP

    Inactivated pentavalent vaccine against mycoplasmosis and salmonellosis for chickens

    Get PDF
    Mycoplasma and Salmonella are serious pathogens threaten the poultry industry. This study aimed to prepare and evaluate an inactivated pentavalent vaccine targeting bacteria, including Salmonella enterica serovar Typhimurium (ST), Salmonella enterica serovar Enteritidis (SE), Salmonella enterica serovar Kentucky (SK), Mycoplasma gallisepticum (MG), and Mycoplasma synoviae (MS), from locally isolated strains. The prepared vaccine was adjuvanted with Montanide ISA70 oil and then tested for safety, sterility, and potency. The vaccine efficacy was evaluated in 110 specific pathogen-free, 1-day-old chicks, which were divided into three groups as follows: 1) vaccinated group (50 birds), which was subdivided into five subgroups of ten birds each; 2) control positive (challenged) group (50 birds), which was subdivided into five subgroups of ten birds each; and 3) control negative (blank) group, which included ten birds. Chicks in group 1 were administered the first dose of vaccine at 7 d of age followed by a booster dose after 3 wk. At 3 wk after booster vaccination, the chicks who were administered the booster dose were challenged and kept under observation until the end of the experiment when the chicks were approximately 10 wk. Details of clinical symptoms, daily mortality, weights, and postmortem lesions; serum samples; cloacal swabs; and nasal swabs were collected during the experiment. The humoral immune response to the prepared pentavalent vaccine was assessed using enzyme-linked immunosorbent assay. Our findings revealed that the prepared vaccine showed high protective antibody titers against Salmonella and Mycoplasma with 100% efficacy and no mortalities (100% survival rate) were recorded in vaccinated and challenged birds. The vaccine reduced both clinical signs and bacterial shedding post challenge in vaccinated birds in comparison with control positive group. The prepared vaccine did not affect the body weight gain of the vaccinated birds in comparison with control negative birds. The current study concluded that locally manufactured inactivated pentavalent vaccine offers protection to birds and could be employed as an effective tool along with biosecurity measures to overcome mycoplasmosis and salmonellosis in layer and breeder chicken farms in Egypt

    Pharmacological, nutritional and antimicrobial uses of Moringa oleifera Lam. leaves in poultry nutrition: An updated knowledge

    Get PDF
    Recently, developing countries have focused on using innovative feed in poultry nutrition. The plant Moringa oleifera is native to India but grows worldwide in tropical and subtropical climates. Moringa is planted on a large scale as it can tolerate severe dry and cold conditions. All parts of this plant can be used for commercial or nutritional purposes, and it has a favorable nutritional profile. Beneficial phytochemicals, minerals, and vitamins are abundant in the leaves. The leaf extracts can be used to treat malnutrition; they also possess anticancer, antioxidant, antidiabetic, antibacterial, and anti-inflammatory properties. Further, moringa contains antinutritional substances, such as trypsin inhibitors, phytates, tannins, oxalates, cyanide, and saponins, which have a harmful effect on mineral and protein metabolism. Previous research suggested that including moringa in chicken diets boosts their growth and productivity. Therefore, this review focuses on the characterization and application of M. oleifera in poultry nutrition and its potential toxicity. Furthermore, we discuss the nutritional content, phytochemicals, and antioxidants of M. oleifera leaf meal and its applicability in poultry rations

    The relationship among avian influenza, gut microbiota and chicken immunity: An updated overview

    Get PDF
    The alimentary tract in chickens plays a crucial role in immune cell formation and immune challenges, which regulate intestinal flora and sustain extra-intestinal immunity. The interaction between pathogenic microorganisms and the host commensal microbiota as well as the variety and integrity of gut microbiota play a vital role in health and disease conditions. Thus, several studies have highlighted the importance of gut microbiota in developing immunity against viral infections in chickens. The gut microbiota (such as different species of Lactobacillus, Blautia Bifidobacterium, Faecalibacterium, Clostridium XlVa, and members of firmicutes) encounters different pathogens through different mechanisms. The digestive tract is a highly reactive environment, and infectious microorganisms can disturb its homeostasis, resulting in dysbiosis and mucosal infections. Avian influenza viruses (AIV) are highly infectious zoonotic viruses that lead to severe economic losses and pose a threat to the poultry industry worldwide. AIV is a challenging virus that affects gut integrity, disrupts microbial homeostasis and induces inflammatory damage in the intestinal mucosa. H9N2 AIV infection elevates the expression of proinflammatory cytokines, such as interferon (IFN-γ and IFNα) and interleukins (IL-17A and IL-22), and increases the proliferation of members of proteobacteria, particularly Escherichia coli. On the contrary, it decreases the proliferation of certain beneficial bacteria, such as Enterococcus, Lactobacillus and other probiotic microorganisms. In addition, H9N2 AIV decreases the expression of primary gel-forming mucin, endogenous trefoil factor family peptides and tight junction proteins (ZO-1, claudin 3, and occludin), resulting in severe intestinal damage. This review highlights the relationship among AIV, gut microbiota and immunity in chicken

    Public Sentiment Analysis and Topic Modeling Regarding COVID-19’s Three Waves of Total Lockdown: A Case Study on Movement Control Order in Malaysia

    Get PDF
    [Abstract] The COVID-19 pandemic has affected many aspects of human life. The pandemic not only caused millions of fatalities and problems but also changed public sentiment and behavior. Owing to the magnitude of this pandemic, governments worldwide adopted full lockdown measures that attracted much discussion on social media platforms. To investigate the effects of these lockdown measures, this study performed sentiment analysis and latent Dirichlet allocation topic modeling on textual data from Twitter published during the three lockdown waves in Malaysia between 2020 and 2021. Three lockdown measures were identified, the related data for the first two weeks of each lockdown were collected and analysed to understand the public sentiment. The changes between these lockdowns were identified, and the latent topics were highlighted. Most of the public sentiment focused on the first lockdown as reflected in the large number of latent topics generated during this period. The overall sentiment for each lockdown was mostly positive, followed by neutral and then negative. Topic modelling results identified staying at home, quarantine and lockdown as the main aspects of discussion for the first lockdown, whilst importance of health measures and government efforts were the main aspects for the second and third lockdowns. Governments may utilise these findings to understand public sentiment and to formulate precautionary measures that can assure the safety of their citizens and tend to their most pressing problems. These results also highlight the importance of positive messaging during difficult times, establishing digital interventions and formulating new policies to improve the reaction of the public to emergency situations.Taiwan. Ministry of Science and Technology; 108-2511-H-224-007-MY

    Improving the time delay in the design of the damping controller with the aim of improving the stability of the power system in the presence of high penetration of renewable energy sources

    Get PDF
    Due to the high penetration of renewable energy sources (RES) such as wind units in power systems, the need to check the stability of transmission networks has been given more attention than before. Therefore, in this paper, due to the importance of the topic, the wide area damping controller (WADC) has been used for the battery energy storage system (BESS) connected to the photovoltaic unit and the permanent magnet synchronous generator (PMSG) in the dc link. The WADC design is based on free weight matrices (FWM), which can solve a set of constraints based on the linear matrix inequality (LMI) based on the delay-dependent feedback control theory. The working method is that the constraints related to LMI are considered in such a way that it has the ability to tolerate the maximum amount of time delay. FWM has been used to communicate between LMI constraints and the maximum value of the time delay margin. FWM matrices are also based on an iterative algorithm based on linearization of the conical complement, which tries to search for the most optimal value for the control parameters. To implement the simulation results in MATLAB software, an improved power system of 16 machines has been used, the results of which are clearly analyzed and show the superiority of the proposed method compared to other mentioned methods

    Accidental Inflation in the Landscape

    Full text link
    We study some aspects of fine tuning in inflationary scenarios within string theory flux compactifications and, in particular, in models of accidental inflation. We investigate the possibility that the apparent fine-tuning of the low energy parameters of the theory needed to have inflation can be generically obtained by scanning the values of the fluxes over the landscape. Furthermore, we find that the existence of a landscape of eternal inflation in this model provides us with a natural theory of initial conditions for the inflationary period in our vacuum. We demonstrate how these two effects work in a small corner of the landscape associated with the complex structure of the Calabi-Yau manifold P^4_[1,1,1,6,9] by numerically investigating the flux vacua of a reduced moduli space. This allows us to obtain the distribution of observable parameters for inflation in this mini-landscape directly from the fluxes.Comment: 40 pages, 11 figure

    Mapping geographical inequalities in childhood diarrhoeal morbidity and mortality in low-income and middle-income countries, 2000–17 : analysis for the Global Burden of Disease Study 2017

    Get PDF
    Background Across low-income and middle-income countries (LMICs), one in ten deaths in children younger than 5 years is attributable to diarrhoea. The substantial between-country variation in both diarrhoea incidence and mortality is attributable to interventions that protect children, prevent infection, and treat disease. Identifying subnational regions with the highest burden and mapping associated risk factors can aid in reducing preventable childhood diarrhoea. Methods We used Bayesian model-based geostatistics and a geolocated dataset comprising 15 072 746 children younger than 5 years from 466 surveys in 94 LMICs, in combination with findings of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, to estimate posterior distributions of diarrhoea prevalence, incidence, and mortality from 2000 to 2017. From these data, we estimated the burden of diarrhoea at varying subnational levels (termed units) by spatially aggregating draws, and we investigated the drivers of subnational patterns by creating aggregated risk factor estimates. Findings The greatest declines in diarrhoeal mortality were seen in south and southeast Asia and South America, where 54·0% (95% uncertainty interval [UI] 38·1–65·8), 17·4% (7·7–28·4), and 59·5% (34·2–86·9) of units, respectively, recorded decreases in deaths from diarrhoea greater than 10%. Although children in much of Africa remain at high risk of death due to diarrhoea, regions with the most deaths were outside Africa, with the highest mortality units located in Pakistan. Indonesia showed the greatest within-country geographical inequality; some regions had mortality rates nearly four times the average country rate. Reductions in mortality were correlated to improvements in water, sanitation, and hygiene (WASH) or reductions in child growth failure (CGF). Similarly, most high-risk areas had poor WASH, high CGF, or low oral rehydration therapy coverage. Interpretation By co-analysing geospatial trends in diarrhoeal burden and its key risk factors, we could assess candidate drivers of subnational death reduction. Further, by doing a counterfactual analysis of the remaining disease burden using key risk factors, we identified potential intervention strategies for vulnerable populations. In view of the demands for limited resources in LMICs, accurately quantifying the burden of diarrhoea and its drivers is important for precision public health
    • …
    corecore