Absence of reflection as a function of the coupling constant

We consider solutions of the one-dimensional equation $-u'' +(Q+ \lambda V) u = 0$ where $Q: \mathbb{R} \to \mathbb{R}$ is locally integrable, $V : \mathbb{R} \to \mathbb{R}$ is integrable with supp$(V) \subset [0,1]$, and $\lambda \in \mathbb{R}$ is a coupling constant. Given a family of solutions $\{u_{\lambda} \}_{\lambda \in \mathbb{R}}$ which satisfy $u_{\lambda}(x) = u_0(x)$ for all $x<0$, we prove that the zeros of $b(\lambda) := W[u_0, u_{\lambda}]$, the Wronskian of $u_0$ and $u_{\lambda}$, form a discrete set unless $V \equiv 0$. Setting $Q(x) := -E$, one sees that a particular consequence of this result may be stated as: if the fixed energy scattering experiment $-u'' + \lambda V u = Eu$ gives rise to a reflection coefficient which vanishes on a set of couplings with an accumulation point, then $V \equiv 0$.Comment: To appear in Journal of Mathematical Physic

Experimental Assessment of Mortality and Hyperglycemia in Tiger Muskellunge Due to Stocking Stressors

Tiger muskellunge (the F1 hybrid of female muskellunge Esox masquinongy and male northern pike E.lucius) have survived poorly when stocked in reservoirs. To understand why, we quantified, in the laboratory, both mortality and plasma glucose responses to three common stocking stressors: dipnet handling, confinement, and temperature increase. No young-of-year hybrids died within 48 h when the temperature was abruptly increased 10C, and only 5% died when the temperature was increased 12C, but 98% died within 4 h when the temperature was increased 15C. Thus, we concluded that thermal stress is an important determinant of poststocking mortality. Mortalities in response to three multiple-stressor treatments--(1) handling and temperature increase, (2) handling, confinement at a fish density of 83 g/L, and temperature increase, and (3) handling, confinement at 135 g/L, and temperature increase--did not differ from each other or from mortality associated with a temperature increase alone. Thus, handling and moderate-density confinement during transport do not necessarily increase poststocking mortality of tiger muskellunge. Abrupt temperature increases of 12 and 15C increased peak plasma glucose concentrations significantly. Handling and confinement together caused a significant hyperglycemia both with and without a temperature increase. However, the relative magnitude of the hyperglycemia caused by individual handling and confinement stressors depended on the presence of a thermal stressor. Finally, we found that plasma glucose concentrations and mortality were not correlated. Although glucose is easily measured and sensitive to small changes in stress, it is not a good indicator of reduced survival and should not be used as such in studies intended to quantify stress-induced mortality.This research was supported in part by funds from the Federal Aid in Fish Restoration Project F-57-R. The Department of Zoology, The Ohio State University, and the Ohio Cooperative Fishery Research Unit also provided financial assistance, computer money, and equipment

A cancer cell-line titration series for evaluating somatic classification.

BackgroundAccurate detection of somatic single nucleotide variants and small insertions and deletions from DNA sequencing experiments of tumour-normal pairs is a challenging task. Tumour samples are often contaminated with normal cells confounding the available evidence for the somatic variants. Furthermore, tumours are heterogeneous so sub-clonal variants are observed at reduced allele frequencies. We present here a cell-line titration series dataset that can be used to evaluate somatic variant calling pipelines with the goal of reliably calling true somatic mutations at low allele frequencies.ResultsCell-line DNA was mixed with matched normal DNA at 8 different ratios to generate samples with known tumour cellularities, and exome sequenced on Illumina HiSeq to depths of &gt;300×. The data was processed with several different variant calling pipelines and verification experiments were performed to assay &gt;1500 somatic variant candidates using Ion Torrent PGM as an orthogonal technology. By examining the variants called at varying cellularities and depths of coverage, we show that the best performing pipelines are able to maintain a high level of precision at any cellularity. In addition, we estimate the number of true somatic variants undetected as cellularity and coverage decrease.ConclusionsOur cell-line titration series dataset, along with the associated verification results, was effective for this evaluation and will serve as a valuable dataset for future somatic calling algorithm development. The data is available for further analysis at the European Genome-phenome Archive under accession number EGAS00001001016. Data access requires registration through the International Cancer Genome Consortium's Data Access Compliance Office (ICGC DACO)

Database management and analysis of fisheries in Illinois: Final report, 1 March 1999-28 February 2002

Issued May 2002; F-69-RReport issued on: May 200

Regional perturbation of gene transcription is associated with intrachromosomal rearrangements and gene fusion transcripts in high grade ovarian cancer.

Genomic rearrangements are a hallmark of cancer biology and progression, allowing cells to rapidly transform through alterations in regulatory structures, changes in expression patterns, reprogramming of signaling pathways, and creation of novel transcripts via gene fusion events. Though functional gene fusions encoding oncogenic proteins are the most dramatic outcomes of genomic rearrangements, we investigated the relationship between rearrangements evidenced by fusion transcripts and local expression changes in cancer using transcriptome data alone. 9,953 gene fusion predictions from 418 primary serious ovarian cancer tumors were analyzed, identifying depletions of gene fusion breakpoints within coding regions of fused genes as well as an N-terminal enrichment of breakpoints within fused genes. We identified 48 genes with significant fusion-associated upregulation and furthermore demonstrate that significant regional overexpression of intact genes in patient transcriptomes occurs within 1 megabase of 78 novel gene fusions that function as central markers of these regions. We reveal that cancer transcriptomes select for gene fusions that preserve protein and protein domain coding potential. The association of gene fusion transcripts with neighboring gene overexpression supports rearrangements as mechanism through which cancer cells remodel their transcriptomes and identifies a new way to utilize gene fusions as indicators of regional expression changes in diseased cells with only transcriptomic data

Management Issues and Their Relative Priority within State Fisheries Agencies

For researchers and managers to work together for greatest mutual benefit, researchers must understand what issues fisheries managers consider most important. To assess management priorities, we conducted a mail survey asking U.S. state fisheries agencies to identify the priority, based on personnel time, they place on 12 fisheries management issues. Based on an 88% response rate, we determined relative emphases across (1) management issues, (2) geographic regions, and (3) freshwater or marine orientations. Issues directly linked to sport and commercial fishers, i.e., stocking, harvest regulations, fishing pressure, and exploring recruitment, were of paramount importance in all agency time budgets. The issue that included conflict, policy, and human dimensions concerns also was identified as "high priority." Six other issueshabitat restoration, hydropower licensing, instream flow, contaminants, introduced species, and nongame species-were of "moderate priority" nationwide. Approximately 50% of the issues varied in emphases across geographic region, and five issues were differentially emphasized in agencies with freshwater and marine responsibilities. To solve persistent problems that plague fisheries management, agencies must clearly identify high-priority management concerns and communicate their specific problem-solving needs to researchers. Results of this survey should provide a first step in identifying these management priorities and research needs