The structure of supervision and pay in hospitals

An examination of the intensity of supervision in the workplace and its effect on the pay of nonsupervisory employees through the use a wage survey of the hospital industry.Wages ; Medical care, Cost of

Self-Organized Criticality and Thermodynamic formalism

We introduce a dissipative version of the Zhang's model of Self-Organized Criticality, where a parameter allows to tune the local energy dissipation. We analyze the main dynamical features of the model and relate in particular the Lyapunov spectrum with the transport properties in the stationary regime. We develop a thermodynamic formalism where we define formal Gibbs measure, partition function and pressure characterizing the avalanche distributions. We discuss the infinite size limit in this setting. We show in particular that a Lee-Yang phenomenon occurs in this model, for the only conservative case. This suggests new connexions to classical critical phenomena.Comment: 35 pages, 15 Figures, submitte

Natural Enemies of Alfalfa Weevil, \u3ci\u3eHypera Postica\u3c/i\u3e (Coleoptera: Curculionidae), in Minnesota

Alfalfa weevil, Hypera postica, is present throughout Minnesota. How- ever, economically damaging populations seldom occur, due to a combination of natural enemies and adverse climatic conditions. Five natural enemies of alfalfa weevil were found in Minnesota. Microctonus aethiopoides (Hymenoptera: Braconidae), a parasitoid of adults, was recovered from 43 of 65 counties surveyed during 1984 and 1985. Tetrastichus incertus (Hymenoptera: Eulophidae) and Bathyplectes curculionis (Hymenoptera: Ichneumonidae), para­sitoids of larvae, were each recovered from 13 of 15 counties surveyed during 1991-1993. Bathyplectes anurus, another parasitoid of larvae, was recovered from one county In 1991, four counties in 1992, and six counties in 1993. Zoophthora phytonomi (Entomophthora: Entomophthoraceae), a pathogen of larvae, was recovered from 14 of 15 counties surveyed in 1991-1993. Winters with low minimum temperatures and little snow cover were detrimental to the weevil. Usually, southeastern Minnesota has milder winters and higher alfalfa weevil populations than other areas of the State. However, even here, because of natural enemies, weevil populations seldom reach economically damaging levels

Thermal induced flow oscillations in heat exchangers for supercritical fluids

Analytical model has been developed to predict possible unstable behavior in supercritical heat exchangers. From complete model, greatly simplified stability criterion is derived. As result of this criterion, stability of heat exchanger system can be predicted in advance

The Application of CRISPR Technology to High Content Screening in Primary Neurons

Axon growth is coordinated by multiple interacting proteins that remain incompletely characterized. High content screening (HCS), in which manipulation of candidate genes is combined with rapid image analysis of phenotypic effects, has emerged as a powerful technique to identify key regulators of axon outgrowth. Here we explore the utility of a genome editingapproach referred to as CRISPR (Clustered Regularly Interspersed Palindromic Repeats) for knockout screening in primary neurons. In the CRISPR approach a DNA-cleaving Cas enzyme is guided to genomic target sequences by user-created guide RNA (sgRNA), where it initiates a double-stranded break that ultimately results in frameshift mutation and loss of protein production. Using electroporation of plasmid DNA that co-expresses Cas9enzyme and sgRNA, we first verified the ability of CRISPR targeting to achieve protein-level knockdown in cultured postnatal cortical neurons. Targeted proteins included NeuN (RbFox3) and PTEN, a well-studied regulator of axon growth. Effective knockdown lagged at least four days behind transfection, but targeted proteins were eventually undetectable by immunohistochemistry in \u3e 80% of transfected cells. Consistent with this, anti-PTEN sgRNA produced no changes in neurite outgrowth when assessed three days post-transfection. When week-long cultures were replated, however, PTEN knockdown consistently increased neurite lengths. These CRISPR-mediated PTEN effects were achieved using multi-well transfection and automated phenotypic analysis, indicating the suitability of PTEN as a positive control for future CRISPR-based screening efforts. Combined, these data establish an example of CRISPR-mediated protein knockdown in primary cortical neurons and its compatibility with HCS workflows

In vitro and In vivo Characterization of the Infection Efficiency of a Modified Retrovirus Envelope Glycoprotein for Targeting Gene Transduction

Attributes of both the viral glycoprotein and its cellular receptor play key roles in determining the outcome of infection. This body of work endeavors to illustrate how these two components influence the efficiency of virus infection in in vitro and in vivo systems with an emphasis on characterizing the transduction capacity of a novel entry-targeting glycoprotein. In previous work, the Moloney murine leukemia virus (MLV) envelope glycoprotein (Env) was modified to generate the Sst-RBS glycoprotein. This glycoprotein was created by replacing the wild type (WT) receptor binding site (RBS), located on the surface subunit (SU) of the Env, with the somatostatin peptide hormone sequence SST-14. The modifications resulted in abrogating transduction via the natural MLV receptor and redirecting transduction to a family of five somatostatin receptors (SSTR). I demonstrate that structural characteristics of the Sst-RBS glycoprotein and the intracellular fate of the SSTR receptor influence the infection efficiency of pseudotyped MLV and human immunodeficiency virus type 1 (HIV-1) based lentiviral (LV) particles. Infection and western blot assays indicate that Sst-RBS retains the structural requirements for mediating levels of transduction that are comparable to WT and approach within 5-fold that of transduction mediated by vesicular stomatitis virus (VSV) G protein when each envelope protein is pseudotyped on MLV particles. To address the contribution of receptor characteristics on infection efficiency, HEK 293 cell lines stably expressing comparable cell surface levels of SSTR-2, SSTR-3 and SSTR-5; which have natural differences in intracellular trafficking; were generated. Infection assays revealed that distinctive SSTR subtype-specific destinations correlated with observable differences in the level of Sst-RBS MLV and LV transduction. Taken together the results of virus binding, internalization kinetics, pH-neutralizing agents, protease inhibitor and penetration assays support that SSTR-5 allows a greater level of transduction because viruses internalized by this subtype are exposed to more permissive intracellular compartments. Specifically, SSTR-5-associated virions are directed to compartments that are more favorable to cytosolic penetration of viral cores than the compartment(s) to which virions bound to subtypes 2 and 3 are directed; possibly due to a more beneficial complement of host cell proteases. These data suggested that receptor characteristics such as the intracellular fate of internalized virus-receptor complexes exert a strong influence on the efficiency of infection. Surprisingly, even though the difference in the in vitro transduction capacity of Sst-RBS and VSV G pseudotyped LV particles was greater than that of the MLV pseudotypes, the difference did not translate to a reduction in in vivo transduction capacity. A pilot study examining the feasibility of in vivo transduction demonstrated proof of principle and identified regions of the murine brain with endogenous surface expression of SSTRs that were as efficiently transduced by Sst-RBS LV as by VSV G LV