Mathematical modelling of antimicrobial resistance in agricultural waste highlights importance of gene transfer rate

Antimicrobial resistance is of global concern. Most antimicrobial use is in agriculture; manures and slurry are especially important because they contain a mix of bacteria, including potential pathogens, antimicrobial resistance genes and antimicrobials. In many countries, manures and slurry are stored, especially over winter, before spreading onto fields as organic fertilizer. Thus these are a potential location for gene exchange and selection for resistance. We develop and analyze a mathematical model to quantify the spread of antimicrobial resistance in stored agricultural waste. We use parameters from a slurry tank on a UK dairy farm as an exemplar. We show that the spread of resistance depends in a subtle way on the rates of gene transfer and antibiotic inflow. If the gene transfer rate is high, then its reduction controls resistance, while cutting antibiotic inflow has little impact. If the gene transfer rate is low, then reducing antibiotic inflow controls resistance. Reducing length of storage can also control spread of resistance. Bacterial growth rate, fitness costs of carrying antimicrobial resistance and proportion of resistant bacteria in animal faeces have little impact on spread of resistance. Therefore effective treatment strategies depend critically on knowledge of gene transfer rates

Does the universe in fact contain almost no information?

At first sight, an accurate description of the state of the universe appears to require a mind-bogglingly large and perhaps even infinite amount of information, even if we restrict our attention to a small subsystem such as a rabbit. In this paper, it is suggested that most of this information is merely apparent, as seen from our subjective viewpoints, and that the algorithmic information content of the universe as a whole is close to zero. It is argued that if the Schr\"odinger equation is universally valid, then decoherence together with the standard chaotic behavior of certain non-linear systems will make the universe appear extremely complex to any self-aware subsets that happen to inhabit it now, even if it was in a quite simple state shortly after the big bang. For instance, gravitational instability would amplify the microscopic primordial density fluctuations that are required by the Heisenberg uncertainty principle into quite macroscopic inhomogeneities, forcing the current wavefunction of the universe to contain such Byzantine superpositions as our planet being in many macroscopically different places at once. Since decoherence bars us from experiencing more than one macroscopic reality, we would see seemingly complex constellations of stars etc, even if the initial wavefunction of the universe was perfectly homogeneous and isotropic.Comment: 17 pages, LATeX, no figures. Online with refs at http://astro.berkeley.edu/~max/nihilo.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/nihilo.html (faster from Europe) or from [email protected]

Towards the Physical Map of the Trypanosoma cruzi Nuclear Genome: Construction of YAC and BAC Libraries of the Reference Clone T. cruzi CL-Brener

Strategies to construct the physical map of the Trypanosoma cruzi nuclear genome have to capitalize on three main advantages of the parasite genome, namely (a) its small size, (b) the fact that all chromosomes can be defined, and many of them can be isolated by pulse field gel electrophoresis, and (c) the fact that simple Southern blots of electrophoretic karyotypes can be used to map sequence tagged sites and expressed sequence tags to chromosomal bands. A major drawback to cope with is the complexity of T. cruzi genetics, that hinders the construction of a comprehensive genetic map. As a first step towards physical mapping, we report the construction and partial characterization of a T. cruzi CL-Brener genomic library in yeast artificial chromosomes (YACs) that consists of 2,770 individual YACs with a mean insert size of 365 kb encompassing around 10 genomic equivalents. Two libraries in bacterial artificial chromosomes (BACs) have been constructed, BACI and BACII. Both libraries represent about three genome equivalents. A third BAC library (BAC III) is being constructed. YACs and BACs are invaluable tools for physical mapping. More generally, they have to be considered as a common resource for research in Chagas diseaseInstituto de Investigaciones en Ingeniería Genética y Biología MolecularEscola Paulista de MedicinaCBMUniversidade de São PauloUniversidade Federal do Rio de JaneiroIPBUniversidad Central de VenezuelaUSBInstituto Oswaldo CruzCEPHUNIFESP, EPMSciEL

FGF-23 in bone biology

Recent studies have demonstrated that levels of fibroblast growth factor 23 (FGF-23), a key regulator of phosphorus and vitamin D metabolism, rise dramatically as renal function declines and may play a key initiating role in disordered mineral and bone metabolism in patients with chronic kidney disease (CKD). The physiologic importance of FGF-23 in mineral metabolism was first identified in human genetic and acquired rachitic diseases and further characterized in animal models. FGF-23 and its regulators, including phosphate regulating endopeptidase homolog, dentin matrix 1 (DMP1), and matrix extracellular phosphoglycoprotein, are made primarily in bone, specifically in osteocytes. Dysregulation of these proteins results in osteomalacia, implicating the osteocyte in the regulation of skeletal mineralization. Studies in pediatric patients with CKD, the majority of whom have altered skeletal mineralization in early stages of CKD, have demonstrated that skeletal expression of both FGF-23 and its regulator, DMP1, are increased in early stages of CKD and that expression of these proteins is associated with alterations in skeletal mineralization. Thus, dysregulation of osteocytic proteins occur very early in the course of CKD and appear to be central to altered bone and mineral metabolism in this patient population

`George Washington Must Go': The Causes and Effects of Great Power Electoral Interventions

This study assesses the causes and effects of partisan great power interventions in the elections of other countries. Such interventions have been a quite common phenomenon extending back to the beginnings of competitive elections and even including the 1796 U.S. Presidential elections (the source of this study's title). Since World War II, such interventions have become quite common: a dataset I constructed of U.S. and Soviet/Russian electoral interventions between 1946 and 2000 finds that there were such interventions in approximately one of every nine competitive national level executive elections during this period. In today's world, in which competitive national level elections are a significant feature of domestic politics in more than half of the states in the international system, partisan electoral interventions will likely become an even more prominent tool in the great powers' arsenal. Nevertheless, there has been scant scholarly research on this topic. As for the causes of electoral interventions this study argues that electoral interventions usually occur when two concurrent conditions exist. The first is the consent and cooperation of a significant domestic actor within the target with a proposed intervention by the great power. The second is that the intervener sees its interests as being endangered by the very different and inflexible preferences held by another significant candidate/party within the target. As for the electoral consequences of electoral intervention, this study argues that they usually significantly increase the electoral chances of the aided candidate and that overt interventions are more effective than covert interventions. Likewise, electoral interventions will be less helpful to the aided party/candidate in founding elections than in later elections.These hypotheses are tested using multiple methods. The first argument concerning the causes of electoral interventions is tested largely through the in-depth analysis of four case studies (utilizing archival documents) in which such interventions were done or seriously considered by a great power chosen out of the abovenoted dataset of electoral interventions. The second set of hypotheses, about the electoral consequences of such interventions, is tested in two different ways. The first is a large N statistical study utilizing a new dataset of all U.S. and USSR/Russian partisan electoral interventions between 1946 and 2000 constructed by the author. The second is a single election level examination of the electoral consequences of such interventions (utilizing exit polls etc.) in four select intervention cases. Utilizing these methods, this study finds strong evidence in support of the arguments presented here as to both questions

`George Washington Must Go': The Causes and Effects of Great Power Electoral Interventions

This study assesses the causes and effects of partisan great power interventions in the elections of other countries. Such interventions have been a quite common phenomenon extending back to the beginnings of competitive elections and even including the 1796 U.S. Presidential elections (the source of this study's title). Since World War II, such interventions have become quite common: a dataset I constructed of U.S. and Soviet/Russian electoral interventions between 1946 and 2000 finds that there were such interventions in approximately one of every nine competitive national level executive elections during this period. In today's world, in which competitive national level elections are a significant feature of domestic politics in more than half of the states in the international system, partisan electoral interventions will likely become an even more prominent tool in the great powers' arsenal. Nevertheless, there has been scant scholarly research on this topic. As for the causes of electoral interventions this study argues that electoral interventions usually occur when two concurrent conditions exist. The first is the consent and cooperation of a significant domestic actor within the target with a proposed intervention by the great power. The second is that the intervener sees its interests as being endangered by the very different and inflexible preferences held by another significant candidate/party within the target. As for the electoral consequences of electoral intervention, this study argues that they usually significantly increase the electoral chances of the aided candidate and that overt interventions are more effective than covert interventions. Likewise, electoral interventions will be less helpful to the aided party/candidate in founding elections than in later elections.These hypotheses are tested using multiple methods. The first argument concerning the causes of electoral interventions is tested largely through the in-depth analysis of four case studies (utilizing archival documents) in which such interventions were done or seriously considered by a great power chosen out of the abovenoted dataset of electoral interventions. The second set of hypotheses, about the electoral consequences of such interventions, is tested in two different ways. The first is a large N statistical study utilizing a new dataset of all U.S. and USSR/Russian partisan electoral interventions between 1946 and 2000 constructed by the author. The second is a single election level examination of the electoral consequences of such interventions (utilizing exit polls etc.) in four select intervention cases. Utilizing these methods, this study finds strong evidence in support of the arguments presented here as to both questions

When the Great Power Gets a Vote: The Effects of Great Power Electoral Interventions on Election Results

What are the electoral consequences of attempts by great powers to intervene in a partisan manner in another country’s elections? Great powers frequently deploy partisan electoral interventions as a major foreign policy tool. For example, the U.S. and the USSR/Russia have intervened in one of every nine competitive national level executive elections between 1946 and 2000. However, scant scholarly research has been conducted about their effects on the election results in the target. I argue that such interventions usually significantly increase the electoral chances of the aided candidate and that overt interventions are more effective than covert interventions. I then test these hypotheses utilizing a new, original dataset of all U.S. and USSR/Russian partisan electoral interventions between 1946 and 2000. I find strong support for both arguments

Review of the Litvaks : a short history of the Jews in Lithuania

Mykolo Romerio universiteta