20 research outputs found
Self Gravitating Fundamental Strings
We study the configuration of a typical highly excited string as one slowly
increases the string coupling. The dominant interactions are the long range
dilaton and gravitational attraction. In four spacetime dimensions, the string
slowly contracts from its initial (large) size until it approaches the string
scale where it forms a black hole. In higher dimensions, the string stays large
until the coupling reaches a critical value, and then it rapidly collapses to a
black hole. The implications for the recently proposed correspondence principle
are discussed.Comment: 20 pages, LaTe
Aboveground burial for managing catastrophic losses of livestock
Background and Aim: Environmental impacts from carcass management are a significant concern globally. Despite a history of costly, ineffective, and environmentally damaging carcass disposal efforts, large animal carcass disposal methods have advanced little in the past decade. An outbreak today will likely be managed with the same carcass disposal techniques used in the previous decades and will likely result in the same economic, health, and environmental impacts. This article overviews the results of one field test that was completed in Virginia (United States) using the aboveground burial (AGB) technique and the disposal of 111 foot-and-mouth disease (FMD) infected sheep in Tunisia using a similar methodology.
Materials and Methods: Researchers in the United States conducted a field test to assess the environmental impact and effectiveness of AGB in decomposing livestock carcasses. The system design included a shallow trench excavated into native soil and a carbonaceous base placed on the bottom of the trenches followed by a single layer of animal carcasses. Excavated soils were subsequently placed on top of the animals, and a vegetative layer was established. A similar methodology was used in Tunisia to manage sheep infected with FMDs, Peste des Petits Ruminants virus, and Bluetongue Virus.
Results: The results of the field test in the United States demonstrated a significant carcass degradation during the 1-year period of the project, and the migration of nutrients below the carcasses appears to be limited thereby minimizing the threat of groundwater contamination. The methodology proved practical for the disposal of infected sheep carcasses in Tunisia.
Conclusions: Based on the analysis conducted to date, AGB appears to offer many benefits over traditional burial for catastrophic mortality management. Ongoing research will help to identify limitations of the method and determine where its application during large disease outbreaks or natural disasters is appropriate
Antibiotic Resistance Profile and Bio-Control of Multidrug-Resistant <i>Escherichia coli</i> Isolated from Raw Milk in Vietnam Using Bacteriophages
E. coli is an important zoonotic pathogen capable of causing foodborne illness and bovine mastitis. Bacteriophages have been increasingly considered a promising tool to control unwanted bacteria. The aim of this study is to determine the antibiotic resistance profile of E. coli isolated from raw milk and the efficacy of phage in controlling multidrug-resistant E. coli in raw milk. Antibiotic susceptibility testing showed the highest resistance rates of E. coli isolates to co-trime (27.34%) and ampicillin (27.34%), followed by streptomycin (25.18%), tetracycline (23.02%), and the lowest resistance rates to ciprofloxacin, gentamycin, and ceftazidime, all at a rate of 2.16%. All isolates were susceptible to meropenem. Of the 139 E. coli isolates, 57 (41.01%) were resistant to at least one antibiotic, and 35 (25.18%) were classified as MDR strains. Molecular characterization indicated that 5 (3.6%) out of the 139 isolates were STEC strains carrying stx1 gene. Seven (5.04%) isolates were phenotypically identified as ESBLEC, and four isolates (2.88%) were resistant to colistin. The results of the genotypic test revealed that four out of seven ESBLEC strains carried both blaTEM and blaCTX-M-1, two harbored blaTEM, and one possessed blaCTX-M-1, while mcr-1 was detected in all four colistin-resistant E. coli isolates. In particular, one isolated E. coli strain (EM148) was determined to be a multidrug-resistant strain simultaneously carrying blaTEM, blaCTX-M-1, and mcr-1. A total of eight phages were successfully recovered from raw milk. The application of phage PEM3 significantly reduced viable counts of multidrug-resistant host EM148 in raw milk by at least 2.31 log CFU/mL at both 24 °C and 4 °C
Prevalence and Antibiotic Resistance Profile of <i>Clostridium perfringens</i> Isolated from Pork and Chicken Meat in Vietnam
Clostridium perfringens is one of the most important zoonotic pathogens as it can cause food poisoning in humans and necrotic enteritis in both animals and humans. Meat, especially pork and chicken meat, is considered the main vehicle for the transmission of C. perfringens from animals to humans. The purpose of this study was to determine the prevalence, toxinotype, and antimicrobial resistance profile of C. perfringens isolated from pork and chicken meat sold in Vietnam. The isolation results showed that 15/50 (30%) of pork samples and 8/50 (16%) of chicken meat samples were contaminated with C. perfringens. The isolates exhibited their highest resistance rate to tetracycline (21/23; 91.30%) and clindamycin (10/23; 43.48%). On the contrary, their lowest resistance rates were observed in response to imipenem (2/23; 8.70%) and cefoxitin (1/23; 4.35%). In particular, 34.78% (8/23) of C. perfringens isolates were identified to be multidrug-resistant strains. The results of toxin genotyping indicated that all isolates were positive for the cpa gene and belonged to type A
Viability of African Swine Fever Virus with the Shallow Burial with Carbon Carcass Disposal Method
African swine fever (ASF) is a highly contagious swine disease with high mortality. In many countries, culling pigs infected and exposed to the ASF virus is mandatory to control the disease, which poses a real challenge in the disposal of large numbers of carcasses during ASF outbreaks. Shallow burial with carbon (SBC) Thanks ew mortality disposal method developed from deep burial and composting. The present study investigates the effectiveness of SBC in disposing of ASF virus-infected pigs. The real-time PCR results showed that DNA of the ASF virus was still detected in bone marrow samples on day 56, while the virus isolation test revealed that the infectious ASF virus was destroyed in both spleen and bone marrow samples on day 5. Interestingly, decomposition was found to occur rapidly in these shallow burial pits. On day 144, only large bones were found in the burial pit. In general, the results of this study indicated that SBC is a potential method for the disposal of ASF-infected carcasses; however, further studies are needed to provide more scientific evidence for the efficacy of SBC in different environment conditions
Composting of Wild Boar Carcasses in Lithuania Leads to Inactivation of African Swine Fever Virus in Wintertime
African swine fever (ASF) continues to spread and persist in the Eurasian wild boar population. The infection pressure resulting from infected carcasses in the environment can be a major contributor to disease persistence and spread. For this reason, it is crucial to find a safe and efficient method of carcass disposal under different circumstances. In the presented study, we investigated open-air composting of carcasses under winter conditions in northeastern Europe, i.e., Lithuania. We can demonstrate that the ASF virus (ASFV) is inactivated in both entire wild boar carcasses and pieces thereof in a time- and temperature-dependent manner. Composting piles reached up to 59.0 °C, and ASFV was shown to be inactivated. However, the ASFV genome was still present until the end of the 112-day sampling period. While further studies are needed to explore potential risk factors (and their mitigation), such as destruction of composting piles by scavengers or harsh weather conditions, composting seems to present a valid method to inactivate the ASFV in wild boar carcasses where rendering or other disposal methods are not feasible. In summary, composting provides a new tool in our toolbox of ASF control in wild boar and can be considered for carcass disposal
Mortality Composting Protocol for Avian Influenza Infected Flocks - FY2016 HPAI Response
Executive Summary of the Method:
Composting is a biological heating process that results in the natural degradation of organic resources (such as poultry carcasses) by microorganisms. Composting has been successfully used throughout the United States for nearly two decades to control outbreaks of low pathogenicity avian influenza (LPAI) and highly pathogenic avian influenza (HPAI).Composting can be effective with most bird types and poultry house designs. Microbial activity within a well-constructed compost pile can generate and maintain temperatures sufficient to inactivate the avian influenza virus. The effectiveness of this virus inactivation process can be assessed by evaluating compost temperatures and the shape of the time and temperature curve, visual observation of carcass decomposition, and the homogeneity of the compost mix. This document can also be accessed at: https://www.aphis.usda.gov/animal_health/emergency_management/downloads/hpai/mortalitycompostingprotocol.pdf