Capital Expenditure Decisions and the Role of the Not-for-Profit Hospital: An Application of a Social Goods Model

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68370/2/10.1177_107755879004700404.pd

Estimating Porosity with Ground-Penetrating Radar Reflection Tomography: A Controlled 3-D Experiment at the Boise Hydrogeophysical Research Site

To evaluate the uncertainty of water-saturated sediment velocity and porosity estimates derived from surface-based, ground-penetrating radar reflection tomography, we conducted a controlled field experiment at the Boise Hydrogeophysical Research Site (BHRS). The BHRS is an experimental well field located near Boise, Idaho. The experimental data set consisted of 3-D multioffset radar acquired on an orthogonal 20 × 30 m surface grid that encompassed a set of 13 boreholes. Experimental control included (1) 1-D vertical velocity functions determined from traveltime inversion of vertical radar profiles (VRP) and (2) neutron porosity logs. We estimated the porosity distribution in the saturated zone using both the Topp and Complex Refractive Index Method (CRIM) equations and found the CRIM estimates in better agreement with the neutron logs. We found that when averaged over the length of the borehole, surface-derived velocity measurements were within 5% of the VRP velocities and that the porosity differed from the neutron log by less than 0.05. The uncertainty, however, is scale dependent. We found that the standard deviation of differences between ground-penetrating-radar-derived and neutron-log-derived porosity values was as high as 0.06 at an averaging length of 0.25 m but decreased to less than 0.02 at length scale of 11 m. Additionally, we used the 3-D porosity distribution to identify a relatively high-porosity anomaly (i.e., local sedimentary body) within a lower-porosity unit and verified the presence of the anomaly using the neutron porosity logs. Since the reflection tomography approach requires only surface data, it can provide rapid assessment of bulk hydrologic properties, identify meterscale anomalies of hydrologic significance, and may provide input for other higherresolution measurement methods

Imaging Complex Structure in Shallow Seismic-reflection Data Using Prestack Depth Migration

Prestack depth migration (PSDM) analysis has the potential to significantly improve the accuracy of both shallow seismic reflection images and the measured velocity distributions. In a study designed to image faults in the Alvord Basin, Oregon, at depths from 25–1000 m, PSDM produced a detailed reflection image over the full target depth range. In contrast, poststack time migration produced significant migration artifacts in the upper 100 m that obscured reflection events and limited the structural interpretation in the shallow section. Additionally, an abrupt increase from ~2500 to \u3e3000 m/s in the PSDM velocity model constrained the interpretation of the transition from sedimentary basin fill to basement volcanic rocks. PSDM analysis revealed a complex extensional history with at least two distinct phases of basin growth and a midbasin basement high that forms the division between two major basin compartments

Abnormal interneuron development in disrupted-in-schizophrenia-1 L100P mutant mice

BACKGROUND: Interneuron deficits are one of the most consistent findings in post-mortem studies of schizophrenia patients and are likely important in the cognitive deficits associated with schizophrenia. Disrupted-in-Schizophrenia 1 (DISC1), a strong susceptibility gene for schizophrenia and other mental illnesses, is involved in neurodevelopment, including that of interneurons. However, the mechanism by which DISC1 regulates interneuron development remains unknown. In this study, we analyzed interneuron histology in the Disc1-L100P single point mutation mouse, that was previously shown to have behavioral abnormalities and cortical developmental defects related to schizophrenia. RESULTS: We sought to determine whether a Disc1-L100P point mutation in the mouse would alter interneuron density and location. First, we examined interneuron position in the developing mouse cortex during embryonic days 14–16 as an indicator of interneuron tangential migration, and found striking migration deficits in Disc1-L100P mutants. Further analysis of adult brains revealed that the Disc1-L100P mutants have selective alterations of calbindin- and parvalbumin-expressing interneurons in the cortex and hippocampus, decreased GAD67/PV co-localization and mis-positioned interneurons across the neocortex when compared to wild-type littermates. CONCLUSION: Our results are consistent with the anomalies seen in post-mortem schizophrenia studies and other Disc1 mutant mouse models. Future research is required to determine the specific mechanisms underlying these cellular deficits. Overall, these findings provide further evidence that DISC1 participates in interneuron development and add to our understanding of how DISC1 variants can affect susceptibility to psychiatric illness

Comparative results of open lower extremity revascularization in nonagenarians

IntroductionThe average lifespan in the United States continues to lengthen. We have observed a similar trend in our patients, with an increased number of nonagenarians presenting for evaluation of vascular disease. This study evaluated outcomes of lower extremity revascularization in patients aged ≥90 years.MethodsThe vascular registry at Albany Medical College was retrospectively reviewed for all lower extremity bypasses performed between 1996 and 2006. We evaluated patient demographics, indications, procedure, patency rates, and complications. Patients were divided into groups based on age ≥90 years (≥90 group) and <90 years (<90 group). Variables were evaluated by χ2 analysis. Outcomes were prepared using life-table methods and compared with log-rank analysis.ResultsDuring the last 10 years, 5443 lower extremity bypasses were performed on patients aged <90 years and 150 on patients aged ≥90 years. The <90 group had significantly more men (61.4% vs 29.3%) and was obviously younger, at 68 years (range 7-89 years) vs 92 years (range, 90-101 years). The <90 group had more comorbidities in terms of diabetes, active tobacco use, and hypercholesterolemia. No significant difference was noted in coronary artery disease or chronic renal insufficiency between the groups. Critical limb ischemia as an indication was significantly higher in the ≥90 group (149 [99%] vs 4472 [82%]; P < .0.5). Strikingly, the primary patency was significantly higher in the ≥90 group at 4 years (77% vs 62%; P < .05). Complication and amputation rates did not differ between the groups. Perioperative (15% vs 3%; P < .05) and 1-year (45% vs 11%; P < .05) mortality rates were significantly higher in the ≥90 group.ConclusionLower extremity bypass for nonagenarians offers acceptable patency and limb salvage but at a significantly higher mortality rate

Increased tRNA modification and gene-specific codon usage regulate cell cycle progression during the DNA damage response

S-phase and DNA damage promote increased ribonucleotide reductase (RNR) activity. Translation of RNR1 has been linked to the wobble uridine modifying enzyme tRNA methyltransferase 9 (Trm9). We predicted that changes in tRNA modification would translationally regulate RNR1 after DNA damage to promote cell cycle progression. In support, we demonstrate that the Trm9-dependent tRNA modification 5-methoxycarbonylmethyluridine (mcm⁵U) is increased in hydroxyurea (HU)-induced S-phase cells, relative to G₁ and G₂, and that mcm⁵U is one of 16 tRNA modifications whose levels oscillate during the cell cycle. Codon-reporter data matches the mcm⁵U increase to Trm9 and the efficient translation of AGA codons and RNR1. Further, we show that in trm9Δ cells reduced Rnr1 protein levels cause delayed transition into S-phase after damage. Codon re-engineering of RNR1 increased the number of trm9Δ cells that have transitioned into S-phase 1 h after DNA damage and that have increased Rnr1 protein levels, similar to that of wild-type cells expressing native RNR1. Our data supports a model in which codon usage and tRNA modification are regulatory components of the DNA damage response, with both playing vital roles in cell cycle progression.National Institute of Environmental Health Sciences (R01 ES015037)National Institute of Environmental Health Sciences (R01 ES017010)National Institute of Environmental Health Sciences (P30 ES002109)Massachusetts Institute of Technology (Westaway Fund)Singapore-MIT Alliance for Research and Technolog

Geophysical Surveys Across the Boise Hydrogeophysical Research Site to Determine Geophysical Parameters of a Shallow, Alluvial Aquifer

At the Boise Hydrogeophysical Research Site (BHRS), we are characterizing the hydrogeophysical parameters of a cobble-and-sand, unconfined aquifer using a wide variety of geophysical methods. Our goal is to develop methods for mapping variations in permeability by combining non-invasive geophysical data with hydrologic measurements. We are using seismic, ground penetrating radar, and electrical methods in a variety of configurations to provide images of and parameter distributions at the BHRS. Issues such as resolution, depth of penetration, and the ability to image the desired parameters will help determine the most effective methods. Supporting data sets from the BHRS include core analyses and geophysical logs from 18 wells at the site. We will use these data to verify our geophysical interpretations. The various geophysical methods and acquisition geometries, combined with the well control, will provide an outstanding data set to characterize the heterogeneity of the subsurface beneath this alluvial aquifer, and find ways to map permeability with geophysical information

Recent sequence variation in probe binding site affected detection of respiratory syncytial virus group B by real-time RT-PCR

Background Direct immuno-fluorescence test (IFAT) and multiplex real-time RT-PCR have been central to RSV diagnosis in Kilifi, Kenya. Recently, these two methods showed discrepancies with an increasing number of PCR undetectable RSV-B viruses. Objectives Establish if mismatches in the primer and probe binding sites could have reduced real-time RT-PCR sensitivity. Study design Nucleoprotein (N) and glycoprotein (G) genes were sequenced for real-time RT-PCR positive and negative samples. Primer and probe binding regions in N gene were checked for mismatches and phylogenetic analyses done to determine molecular epidemiology of these viruses. New primers and probe were designed and tested on the previously real-time RT-PCR negative samples. Results N gene sequences revealed 3 different mismatches in the probe target site of PCR negative, IFAT positive viruses. The primers target sites had no mismatches. Phylogenetic analysis of N and G genes showed that real-time RT-PCR positive and negative samples fell into distinct clades. Newly designed primers-probe pair improved detection and recovered previous PCR undetectable viruses. Conclusions An emerging RSV-B variant is undetectable by a quite widely used real-time RT-PCR assay due to polymorphisms that influence probe hybridization affecting PCR accuracy

On the Fast Direct Solution of a Preconditioned Electromagnetic Integral Equation

This work presents a fast direct solver strategy for electromagnetic integral equations in the high-frequency regime. The new scheme relies on a suitably preconditioned combined field formulation and results in a single skeleton form plus identity equation. This is obtained after a regularization of the elliptic spectrum through the extraction of a suitably chosen equivalent circulant problem. The inverse of the system matrix is then obtained by leveraging the Woodbury matrix identity, the low-rank representation of the extracted part of the operator, and fast circulant algebra yielding a scheme with a favorable complexity and suitable for the solution of multiple right-hand sides. Theoretical considerations are accompanied by numerical results both of which are confirming and showing the practical relevance of the newly developed scheme