The Unpaid Internship: Benefits, Drawbacks, and Legal Issues

This article hopes to clear up some of the confusion surrounding unpaid internships by discussing who participates in such internships, the merits and drawbacks relative to paid internships, and the relevant legal issues. This summary of existing research provides several key insights, which are of interest to potential interns as well as educators. For students, the literature suggests that unpaid internships are different from their paid counterparts in a variety of ways and pose certain risks that paid internships do not. On an institutional level, this paper documents the unique legal environment surrounding the unpaid internship and notes the unique liabilities program administrators may face if they fail to act with caution

Is SGR 1900+14 a Magnetar?

We present RXTE observations of the soft gamma--ray repeater SGR 1900+14 taken September 4-18, 1996, nearly 2 years before the 1998 active period of the source. The pulsar period (P) of 5.1558199 +/- 0.0000029 s and period derivative (Pdot) of (6.0 +/- 1.0) X 10^-11 s/s measured during the 2-week observation are consistent with the mean Pdot of (6.126 +/- 0.006) X 10^-11 s/s over the time up to the commencement of the active period. This Pdot is less than half that of (12.77 +/- 0.01) X 10^-11 s/s observed during and after the active period. If magnetic dipole radiation were the primary cause of the pulsar spindown, the implied pulsar magnetic field would exceed the critical field of 4.4 X 10^13 G by more than an order of magnitude, and such field estimates for this and other SGRs have been offered as evidence that the SGRs are magnetars, in which the neutron star magnetic energy exceeds the rotational energy. The observed doubling of Pdot, however, would suggest that the pulsar magnetic field energy increased by more than 100% as the source entered an active phase, which seems very hard to reconcile with models in which the SGR bursts are powered by the release of magnetic energy. Because of this, we suggest that the spindown of SGR pulsars is not driven by magnetic dipole radiation, but by some other process, most likely a relativistic wind. The Pdot, therefore, does not provide a measure of the pulsar magnetic field strength, nor evidence for a magnetar.Comment: 14 pages, aasms4 latex, figures 1 & 2 changed, accepted by ApJ letter

Mapping of Three Genes to Pig Chromosome 7q Demonstrates the Similarity with Human Chromosomes 14q and 15q

Previous data have suggested the presence of pork quality quantitative trait loci (QTL) on pig chromosome (SSC) 7q. Improving the resolution of the pig-humanmouse comparative map in this region can facilitate the search for candidate genes for these possible QTL. Therefore, three genes, the cytochrome P-450, subfamily I, polypeptide 1 (CYP1A1), somatostatin receptor 1 (SSTR1), and transcription termination factor 1 (TTF1) genes, all with expected location on pig chromosome 7 based on painting studies, were selected for mapping in the pig. Porcine sequence tagged sites (STSs) spanning 0.9 - 1.5 kb genomic DNA sequence were generated and all genes were physically assigned to SSC7q12-q23, q26 using a pig/rodent somatic cell hybrid panel. Direct sequencing of polymerase chain reaction (PCR) products from different breeds revealed single nucleotide polymorphisms (SNPs) in all genes. The SSTR1 and CYP1A1 single SNPs allowed simple genotyping with PCR-restriction fragment length polymorphism (RFLP) analysis, and were informative for linkage mapping with the PiGMaP reference families. This revealed that SSTR1 is closely linked to CYP1A1 (0.0 cM; LOD = 11.1) and ANPEP (0.0 cM; LOD = 9.0), which refined the localization of a breakpoint in the linkage map between regions with homology to human chromosome 15q (represented by CYP1A1 and ANPEP) and proximal 14q (represented by SSTR1). Moreover, multipoint linkage data suggest inverse homology between human chromosome 14q11-q13 and and pig chomosome 7q. The TTF1 SNP was confirmed by allele-specific PCR but was not informative in any of the families used for linkage analysis.

Genetic Control of Immune Responsiveness: A Review of Its use as a Tool for Selection for Disease Resistance

Disease resistance and immune responsiveness have been traits generally ignored by animal breeders. Recent advances in immunology and molecular biology have opened new avenues towards our understanding of genetic control of these traits. The major histocompatibility gene complex (MHC) appears to play a central role in all immune functions and disease resistance. The need to understand the relationship between immune responsiveness, disease resistance and production traits is discussed in this review. Antagonistic relationships might prevent simultaneous improvement of all of these traits by conventional breeding methods. It is suggested that genetic engineering methods may allow the simultaneous improvement of disease resistance and production traits in domestic animals. Genes of the MHC will be especially good candidates for genetic engineering experiments to improve domestic species

Rapid communication: BslI polymorphism at the swine alpha-actinin2 locus

Source and Description of Clone. A 1.9-kb partial cDNA insert of porcine a-actinin2 in a pBluescript SKphagemid vector was isolated from a swine adult skeletal muscle cDNA lambda ZAP11 library (kindly provided by Charles Louis, University of Minnesota)

Mapping of the Melatonin Receptor 1a (MTNR1A) Gene in Pigs, Sheep and Cattle

Human and sheep Melatonin receptor 1a (MTNR1A) gene information was used to clone a portion of the coding region of this gene in pigs, and to identify polymorphisms of the gene for its assignment to both the genetic linkage and physical maps. MTNR1A maps to pig chromosome 17, establishing a new region of conserved synteny between this chromosome and human chromosome 4. Furthermore, we have assigned MTNR1A to bovine chromosome 27 and sheep chromosome 26. The addition of genes like MTNR1A to livestock genome maps allows questions about evolutionary events and the genetic basis for quantitative traits in livestock to be addressed

Use of an animal model in situations of limited subclass numbers and high degrees of relationships

Breeding value estimation procedures for two traits with moderate and high heritability were evaluated by using a single-trait animal model and computer-simulated data designs. Of interest were the effects of differing numbers of animals and degrees of relationships among animals within and across contemporary groups (tests). Test effects were assumed fixed and animal effects were assumed random. Family size, number of families per contemporary group, and degree of genetic relationships within and across contemporary groups were varied to determine interrelationships among the factors. Results were compared on the basis of accuracy by using both the correlation of true and estimated breeding values and the prediction error variance obtained from the inverse of the coefficient matrix of the mixed-model equations. Small contemporary groups in conjunction with evaluation of closely related families caused average accuracy to decrease relative to that obtained with the same number of unrelated animals because genetically related animals were less accurately evaluated relative to one another. Connecting contemporary groups with a genetic relationship matrix formed a large set of interdependent equations and improved the average accuracy of predicted breeding values. The slight decrease in accuracy for genetically related animals was more than offset by the increase in accuracy of evaluation for their unrelated test mates because the proportion of fixed effects to random effects was smaller. Care must be exercised in designing evaluation schemes involving small populations, and the decision of which fixed effects to include in the model is critical

Heterogeneity of opioid receptor binding in brain slices

A methodological approach was established for the study of ligand binding to multiple opioid receptors in slices from rat brain striatum. Specific binding of radiolabeled opiates was resolved from total binding with enantiomers or excess unlabeled ligand. Equilibrium binding of triated etorphine, dihydromorphine, and ethylketocyclazocine, and competitive displacement of [ 3 H]dihydromorphine by the unlabeled opiates were used to assess both high and low affinity receptor sites. The high-affenity binding components of the radiolabeled opiates were characterized by linear Scatchard plots, K d values of 2.8–3.7 nM, and binding site densities of 180-297 fmol/mg protein. The displacement of [ 3 H]etorphine by morphine and ethylketocyclazocine displayed Hill coefficients of 0.62 and 0.47, respectively, and revealed receptor sites with much lower affinities than those described by the direct binding of these opiates. On the other hand, both morphine and ethylketocyclazocine displaced [ 3 H]dihydromorphine with similar high potencies (apparent K d s, 3-4 nM). The results support the feasibility of using brain slices as a cellular preparation to study opioid receptor mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50218/1/490180214_ftp.pd

Cell-free prediction of protein expression costs for growing cells

Translating heterologous proteins places significant burden on host cells, consuming expression resources leading to slower cell growth and productivity. Yet predicting the cost of protein production for any given gene is a major challenge, as multiple processes and factors combine to determine translation efficiency. To enable prediction of the cost of gene expression in bacteria, we describe here a standard cell-free lysate assay that provides a relative measure of resource consumption when a protein coding sequence is expressed. These lysate measurements can then be used with a computational model of translation to predict the in vivo burden placed on growing E. coli cells for a variety of proteins of different functions and lengths. Using this approach, we can predict the burden of expressing multigene operons of different designs and differentiate between the fraction of burden related to gene expression compared to action of a metabolic pathway

Zebrafish Model of MLL-Rearranged Acute Myeloid Leukemia

Background: Acute myeloid leukemia (AML) is the second most common type of leukemia. Standard treatment includes chemotherapy as well as stem cell transplantation, but for aging patients and those with impaired immune function these rigorous therapies are not always possible. Furthermore, AML patients harboring a chromosomal rearrangement involving Multiple Lineage Leukemia (MLL) exhibit far worse prognoses than patients without. Given these circumstances new therapies must be developed. Methods: Danio rerio (zebrafish) has emerged as a powerful model organism for investigating human blood malignancies due to the conservation of hematopoiesis between humans and zebrafish. We developed a transient transgenic model exhibiting AML characteristics by microinjecting single-cell zebrafish embryos with a tissue specific MLL-ENL expression construct. Results: We found that the expression of MLL-ENL induced a clustered expansion of MLL+ and pu.1+ myeloid cells on the yolk sac at 48 and 72 hours post fertilization (hpf). To characterize our transient AML model, we treated MLL-ENL expressing embryos with either one of or a combination of two drugs that are currently being used in human AML drug trials, Venetoclax and Flavopiridol. We found that treatment with either drug reduced the myeloid expansion induced by the expression of MLL-ENL, and that co-treatment reduced the observed myeloid expansion even further. Conclusions: Although further analysis is required, these data suggest that we successfully developed a transient transgenic AML model in zebrafish. Furthermore, these data suggest that Venetoclax and Flavopiridol co-treatment could yield better outcomes for AML patients than treatment with either drug individually.https://scholarscompass.vcu.edu/gradposters/1112/thumbnail.jp