67 research outputs found
Paraphrasing away properties with pluriverse counterfactuals
In this paper, I argue that for the purposes of ordinary reasoning, sentences about properties of concrete objects can be replaced with sentences concerning how things in our universe would be related to inscriptions were there a pluriverse. Speaking loosely, pluriverses are composites of universes that collectively realize every way a universe could possibly be. As such, pluriverses exhaust all possible meanings that inscriptions could take. Moreover, because universes necessarily do not influence one another, our universe would not be any different intrinsically if there were a pluriverse. These two facts enable anti-realists about abstract objects to replace, e.g. talk of anatomical features with talk of the inscriptions concerning anatomical structure that would exist were there a pluriverse. The availability of such replacements enables anti-realists to carry out essential ordinary reasoning without referring to properties, thereby making room for a consistent anti-realist worldview. The inscriptions of the would-be pluriverse are so numerous and varied that sentences about them can play the roles in ordinary reasoning served by simple sentences about properties of concrete objects
A Lewisian Argument Against Platonism, or Why Theses About Abstract Objects Are Unintelligible
In this paper, I argue that all expressions for abstract objects are meaningless. My argument closely follows David Lewis’ argument against the intelligibility of certain theories of possible worlds, but modifies it in order to yield a general conclusion about language pertaining to abstract objects. If my Lewisian argument is sound, not only can we not know that abstract objects exist, we cannot even refer to or think about them. However, while the Lewisian argument strongly motivates nominalism, it also undermines certain nominalist theories
Applied Mathematics without Numbers
In this paper, I develop a "safety result" for applied mathematics. I show that whenever a theory in natural science entails some non-mathematical conclusion via an application of mathematics, there is a counterpart theory that carries no commitment to mathematical objects, entails the same conclusion, and the claims of which are true if the claims of the original theory are "correct": roughly, true given the assumption that mathematical objects exist. The framework used for proving the safety result has some advantages over existing nominalistic accounts of applied mathematics. It also provides a nominalistic account of pure mathematics
Detergent and sanitizer stresses decrease the thermal resistance of Enterobacter sakazakii in infant milk formula
Infant milk formula has been identified as a potential source of Enterobacter sakazakii. This bacterium can cause a severe form of neonatal meningitis and necrotizing entercolitis. This study determined the effect of acid, alkaline, chlorine and ethanol stresses on the thermal inactivation of E. sakazakii in infant milk formula. Stressed cells were mixed with reconstituted powdered infant milk formula (PIMF) at temperatures between 52 and 58°C for various time periods or mixed with PFMF prior to reconstitution with water at temperatures between 50 and 100°C. The D- and z-values of the cells were determined using linear regression analysis. Detergent and sanitizer stresses decreased the thermal resistance of E. sakazakii in powdered and reconstituted infant milk formula. The values for Z)- acid, alkaline, chlorine and ethanol stressed E. sakazakii at 52-58°C were 14.57-0.54, 12.07-0.37, 10.08-0.40 and 11.61-0.50 min, respectively. The values of alkaline, chlorine and ethanol stressed cells were significantly lower than those of unstressed cells. Only the z-value (4.4°C) of ethanol stressed E. sakazakii was significantly different than that of unstressed cells (4.12°C). Reconstitution at 60°C did not significantly reduce the number of pre-stressed E. sakazakii cells compared with unstressed control cells, whereas significant decreases were obtained at 70°C. Using water at 70°C during the preparation of reconstituted PIMF before feeding infants, may be a suitable and applicable means of reducing the risk of E. sakazakii in the formula. The results of this study may be of use to regulatory agencies, infant milk producers and infant caregivers to design heating processes to eliminate E. sakazakii that may be present in infant milk formula
Getting Back in Shape: Persistence, Shape, and Relativity
In this paper, we will introduce a novel argument (the "Region Argument") that objects do not have frame-independent shapes in special relativity. The Region Argument lacks vulnerabilities present in David Chalmers' argument for that conclusion based on length contraction. We then examine how views on persistence interact with the Region Argument. We argue that this argument and standard four-dimensionalist assumptions entail that nothing in a relativistic world has any shape, not even stages or the regions occupied by them. We also argue that endurantists have viable ways of preserving shape despite the Region Argument. The upshot of these arguments is that contrary to conventional wisdom, considerations about shape in relativity support endurantism rather than four-dimensionalism. We conclude by examining the implications of our discussion for the debate over Edenic shapes, noting that endurantists have a satisfying response to skeptical arguments about Edenic shapes similar to the one they have against the Region Argument
Effect of desiccation, starvation, heat, and cold stresses on the thermal resistance of Enterobacter sakazakii in rehydrated infant milk formula
Enterobacter sakazakii has been implicated in outbreaks of meningitis, septicemia, and necrotizing enterocolitis in immunocompromised and premature neonates. In this study, the effect of desiccation stress, starvation stress, heat shock and cold shock on thermal inactivation of E. sakazakii in rehydrated infant milk formula was evaluated. Stressed cells were mixed with rehydrated infant milk formula at 52, 54, 56, and 58°C for various time periods. The D- and z-values were determined by using linear regression analysis. Z)-values for unstressed E. sakazakii at 52, 54, 56 and 58°C were 15.33, 4.53, 2.00 and 0.53 min, respectively. Desiccation and heat stress, but not starvation or cold stress, caused significant reduction in Z)-values. For example, D52 was 15.33 min for unstressed cells compared with 8.72 and 7.36 after desiccation and heat stress. Z-values of 53 desiccated, starved, heat shocked and cold shocked E. sakazakii were not significantly different from unstressed cells (4.22°C). The results of this study may be of use to regulatory agencies, infant milk producers and infant caregivers to design heating processes to eliminate E. sakazakii that may be present in infant milk formula
Survival and growth of Cronobacter species (Enterobacter) sakazakii in wheat-based infant follow on formulas
Aim: To determine the survival and growth characteristics of Cronobacter species (Enterobacter sakazakii) in infant wheat-based formulas reconstituted with water, milk, grape juice or apple juice during storage. Methods and Results: Infant wheat-based formulas were reconstituted with water, UHT milk, pasteurized grape or apple juices. The reconstituted formulas were inoculated with C. sakazakii and C. muytjensii and stored at 4, 25 or 37°C for up to 24h. At 25 and 37°C, Cronobacter grew more (>5 logio) in formulas reconstituted with water or milk than those prepared with grape or apple juices (ca. 2-3 logio). The organism persisted, but did not grow in any formulas stored at 4°C. Formulas reconstituted with water and milk decreased from pH 6.0 to 4.8-5.0 after 24h, whereas the pH of the formulas reconstituted with fruit juices remained at their initial pH values, ca. pH 4.8-5.0. Conclusion: C sakazakii and C muytjensii can grow in reconstituted wheat-based formulas. If not immediately consumed, these formulas should be stored at refrigeration temperatures to reduce the risk of infant infection. Significance and Impact of the Study: The results of this study will be of use to regulatory agencies and infant formula producers to recommend storage conditions that reduce the growth of Cronobacter in infant wheat-based formulas
Biofilm formation on enteral feeding tubes by Cronobacter sakazakii, Salmonella serovars and other Enterobacteriaceae
WHO (2007) recommended that to reduce microbial risks, powdered infant formula should be reconstituted with water at temperatures >70 °C, and that such feeds should be used within 2 h of preparation. However, this recommendation does not consider the use of enteral feeding tubes which can be in place for more than 48 h and can be loci for bacterial attachment. This study determined the extent to which 29 strains of Cronobacter sakazakii, Salmonella serovars, other Enterobacteriaceae and Acinetobacter spp. can adhere and grow on enteral feeding tubes composed of polyvinyl chloride and polyurethane. The study also included silver-impregnated tubing which was expected to have antibacterial activity. Bacterial biofilm formation by members of the Enterobacteriaceae was ca. 105-106 cfu/cm after 24 h. Negligible biofilm was detected for Acinetobacter gensp. 13; ca. 10 cfu/cm, whereas Cr. sakazakii strain ATCC 12868 had the highest biofilm cell density of 107 cfu/cm. Biofilm formation did not correlate with capsule production, and was not inhibited on silver-impregnated tubing. Bacteria grew in the tube lumen to cell densities of 107 cfu/ml within 8 h, and 109 cfu/ml within 24 h. It is plausible that in vivo the biofilm will both inoculate subsequent routine feeds and as the biofilm ages, clumps of cells will be shed which may survive passage through the neonate's stomach. Therefore biofilm formation on enteral feeding tubes constitutes a risk factor for susceptible neonates
Comparison of methods for the microbiological identification and profiling of cronobacter species from ingredients used in the preparation of infant formula
Cronobacter spp. (formerly Enterobacter sakazakii) can be isolated from a wide range of foods and environments, and its association with neonatal infections has drawn considerable attention from regulatory authorities. The principle route of neonatal infection has been identified as the ingestion of contaminated infant formula. A number of methods have been developed to identify Cronobacter spp., however these were before the most recent (2012 ) taxonomic revision of the genus into seven species. In this study, phenotyping, protein profiling and molecular methods were used to identify Cronobacter strains which had been recently isolated from ingredients used in the preparation of infant formula. Pulsed field gel electrophoresis revealed that different Cronobacter strains had been recovered from the same food products. All isolates were identified as C sakazakii according to four genus specific PCR-probes and protein profiling using MALDI-TOF analysis. However, 16S rDNA sequence analyses and fusA allele sequencing gave more accurate identification: four strains were C sakazakii, one strain was C malonaticus and the remaining strain was C universalis. Multilocus sequence typing showed the strains were different sequence types. These results demonstrate the presence of different Cronobacter species in food ingredients used in the preparation of infant formula, and also the need for molecular identification and profiling methods to be revised according to taxonomic revisions
The Cronobacter genus: ubiquity and diversity
Members of the Cronobacter genus (formerly Enterobacter sakazakii) have become associated with neonatal infections and in particular contaminated reconstituted infant formula. However this is only one perspective of the organism since the majority of infections are in the adult population, and the organism has been isolated from the enteral feeding tubes of neonates on non-formula diets. In recent years methods of detection from food and environmental sources have improved, though accurate identification has been problematic. The need for robust identification is essential in order to implement recent Codex Alimentarius Commission (2008) and related microbiological criteria for powdered infant formula (PIF; intended target age 0-6 months). Genomic analysis of emergent pathogens is of considerable advantage in both improving detection methods, and understanding the evolution of virulence. One ecosystem for Cronobacter is on plant material which may enable the organism to resist desiccation, adhere to surfaces, and resist some antimicrobial agents. These traits may also confer survival mechanisms of relevance in food manufacturing and also virulence mechanisms
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