cssi/SciSciGPT-SciSciNet huggingface dataset:
Impact of Perioperative Pain Control on Knee Range of Motion and Development of Arthrofibrosis Following Primary Total Knee Arthroplasty.

Abstract Background Inadequate pain control following total knee arthroplasty (TKA) has been postulated to negatively impact knee range of motion (ROM). We sought to determine the association between perioperative pain levels and knee ROM at 3-month follow-up or need for manipulation under anesthesia (MUA). Methods We retrospectively reviewed 2243 primary TKAs performed from 2002 to 2019 at a single academic center using an institutional total joint registry. Mean age was 68, mean body mass index was 32.8, and 59% were female. Knee ROM was measured preoperatively and 3 months postoperatively. Change in knee ROM, rates of soft tissue contracture, and MUA were assessed in relation to in-hospital 10-point pain visual analog scale (VAS) measurements. Results Overall, 44% had improved ROM at 3-month follow-up, 29% had no change in ROM, and 27% had worsened ROM. There was no significant difference in mean VAS scores of patients with improved, unchanged, or worsened ROM postoperatively (3.0 vs 2.8 vs 3.0; P = .068). There was no significant difference in mean VAS scores of patients who developed a soft tissue contracture or required MUA vs those who did not develop these complications (2.7 vs 2.9; P = .24). Similarly, no significant relationship with these outcomes was identified when maximum and discharge VAS scores were analyzed. Conclusion Comparable ROM and rates of MUA based on in-hospital pain levels were observed in this large series of primary TKA patients. While significant early pain may limit participation in ROM exercises initially, this does not appear to have a marked impact on ROM-related complications for most patients. Level of Evidence III, Therapeutic.
Delivering PrEP to adults with "low" or "no" HIV risk and youth: experiences and perspectives of PrEP providers.

Health care providers have an important role to play in expanding PrEP uptake to populations disproportionately burdened by HIV. In this study, in-depth, semi-structured qualitative interviews were...
HIV service interruptions during the COVID-19 pandemic in China: the role of HIV service challenges and institutional response from healthcare professional's perspective

BackgroundThe healthcare system in China was largely overwhelmed during the unprecedented pandemic of coronavirus disease (COVID-19). HIV-related services have been unavoidably interrupted and impacted. However, the nature and scope of HIV service interruptions due to COVID-19 has rarely been characterized in China and how HIV service challenges affect the service interruptions are also unclear. The current study aimed at characterize HIV service interruption levels and analyzed its associated factors related to service challenges and institutional response from HIV healthcare providers viewpoint. MethodsA cross-sectional online survey was conducted among 1,029 HIV healthcare providers in Guangxi, China, from April to May 2020. Latent class analysis (LCA) was first used to identify HIV service interruption levels. Then hierarchical multinomial logistic regression was conducted to analyze the relationships of HIV care service challenges and institutional response with HIV service interruption levels. Simple slope analysis was employed to examine interaction effects between HIV service challenges and institutional response to COVID-19. ResultsFour classes of HIV service interruption were identified using LCA, with 22.0% complete interruption (class 1), 15.4% moderate interruption (class 2), 21.9% minor interruption (class 3) and 40.7% almost no interruption (class 4). Using class 4 as a reference group, HIV care service challenges were positively associated with the probabilities of service interruptions (Class 1: AOR=1.23, 95%CI: 1.19[~]1.26; Class 2: AOR= 1.10, 95%CI: 1.08[~]1.13; Class 3: AOR= 1.10, 95%CI: 1.08[~]1.12). Institutional response to HIV healthcare delivery was negatively associated with the probabilities of being classified into Class 1 ("Complete interruption") (AOR=0.97, 95%CI: 0.93[~]1.00) and Class 3 ("minor interruption [Outreach service]") (AOR=0.96, 95%CI: 0.93[~]0.99) as compared to Class 4 ("almost no interruption"). Institutional response to HIV healthcare delivery moderated the association of HIV service challenges with complete interruption, but not with the moderate or minor interruption when comparing with no interruption group. ConclusionsA substantial HIV service interruptions occurs due to the COVID-19 pandemic, particularly services that require face-to-face interactions, such as VCT counselling, follow up and outreach services. HIV service challenges largely hinder the HIV service delivery. Institutional response to HIV healthcare delivery could marginally buffer the negative effect of service challenges on complete HIV service interruptions. To maintain continuity of core HIV services in face of a pandemic, build a resilient health care system with adequate preparedness is necessary.
Inhibition of resistant triple-negative breast cancer cells with low-dose 6-mercaptopurine and 5-azacitidine

Highly adaptable breast cancer cells that can opportunistically switch between proliferation and quiescence are often responsible for disease relapse. We have developed a function-based selection strategy for such resistant cells, exemplified by SUM149-MA and FC-IBC02-MA triple-negative breast cancer cells. We have also reported that a lengthy treatment with low-dose 6-mercaptopurine, a clinically useful anti-inflammatory drug, inhibits such resistant cells. To more rigorously test the clinical suitability of 6-mercaptopurine, here we investigated effects of further lowering its dose and the possibility of overcoming resistance to single-drug treatment by combining the drug with another ribonucleoside analog 5-azacitidine. We found that that a lengthy treatment with 1 μM 5-azacitidine, without a significant effect on cell proliferation, sensitized cancer cells to the inhibitory effects of low-dose 6-mercaptopurine. Importantly, treatment for several weeks with low doses of 6-mercaptopurine and/or 5-azacitidine did not render cancer cells resistant to chemotherapeutic drugs doxorubicin or paclitaxel. In fact, the cells became more sensitive to chemotherapeutic drugs upon treatment with 6-mercaptopurine and/or 5-azacitidine. Our analyses of protein markers of epithelial-to-mesenchymal transition indicated that treatments with 6-mercaptopurine and/or 5-azacitidine do not significantly reverse this process in our model. Our results showed that safe drugs such as low-dose 6-mercaptopurine singly or combined with 5-azacitidine, which are suitable for use prior to disease relapse, have a potential of inhibiting highly resistant triple-negative breast cancer cells.
Characterization of Flat Radomes for 18-45 GHz High-Power Horn Antennas

A combined computational and experimental study of flat radome materials for their use with high-power horn antennas operating over 18-45 GHz range is performed. The impact of a monolithic, thin-wall radome on antenna performance in the thermal, mechanical, and electromagnetic domains is considered. The structure must thermally handle high continuous wave power as well as mechanically withstand the impact of pressurization while preserving the electrical performance of a radome-less configuration. A simple test set for measuring radome deflection under high pressure is also discussed. Studies with available materials are conducted and it is found that the 76 μm thick Teflon coated fiberglass has the best performance balance in all domains. Other non-porous materials with comparable electrical and mechanical parameters will have similar behavior.
ANACIN-X: A software framework for studying non-determinism in MPI applications

Abstract Non-determinism in MPI applications negatively impacts the debugging and correctness of high performance computing (HPC) and scientific simulations. To help developers and scientists study and understand sources of non-determinism, we present ANACIN-X, a software framework for quantifying point-to-point communication non-determinism in MPI applications as graph kernel distances. ANACIN-X includes three benchmark applications for testing (i.e., message race, algebraic multigrid, and unstructured mesh).
Vive La Petite Difference - Debt Rating Policy and Yield Differentials between Senior and Subordinated Debt

Corporations seem to issue much more senior than subordinated debt and ratings agencies seem to treat these two types of bonds very differently. We document and explore these differences between senior and subordinated debt. Unlike previous work which focused on rating changes, this paper considers bond ratings at issue. Agencies such as Moody's or S&P rate subordinated bonds by notching them down from senior bonds. We document the market pricing of both senior and subordinated issues. If notching policies were done properly, then we should find that all equally rated bonds should be priced equally (same yield). However, we find that the market systematically prices differently bonds of identical ratings but different seniority. Specifically, we find that yields of speculative senior bonds are higher than the yields of similarly rated subordinated bonds. The sign reverses in most cases for investment grade issues. We provide a conceptual model based upon market frictions which incorporates all our empirical findings.
Intensity-Based Permit Quotas and the Business Cycle: Does Flexibility Pay Off?

Tradable permit markets for carbon dioxide (C02) emissions respond to short-run fluctuations in economic activity. To provide stability, both price and quantity interventions have been proposed. This paper focuses on the relative performance of fixed versus intensity allowances in the presence of both productivity and energy price uncertainty. Both instruments achieve the same steady-state emissions reduction target of 20 percent, which is similar to the current policy proposals, and the regulator then chooses the allowance policy that has the lowest expected abatement cost. A standard real business cycle (RBC) model is used to solve for the expected abatement cost under both policies. Expected cost outcomes are compared using data from the U.S. economy as the baseline scenario. Unlike previous studies, this paper’s results show that, under a reasonable model calibration, fixed allowances outperform intensity allowances by a cost difference of as much as 30 percent.
Nanocomposites, Metal-Filled

Because of surface effects and the dramatic changes in properties that occur when the critical length governing some phenomenon (eg, magnetic, structural) becomes comparable with size, metal clusters have unique characteristics (eg, plasmon absorption, near-IR photoluminescence, superparamagnetism). The embedding of metal clusters into polymeric matrices represents a simple way to take advantage of mesoscopic metal characteristics. Polymer-embedded metal clusters represent a new class of advanced composite materials that may find important applications in different technological areas. Keywords: clusters; nanocomposites; nanostructured materials; polymers; synthesis; applications; review
Delaware's Corporate-Law System: Is Corporate America Buying an Exquisite Jewel or a Diamond in the Rough? A Response to Kahan & Kamar's Price Discrimination in the Market for Corporate Law

In this response to Professors Marcel Kahan and Ehud Kamar's article titled Price Discrimination in the Market for Corporate Law, Vice Chancellor Strine addresses Professors Kahan and Kamar's contention that Delaware's system of corporate law inefficiently subjects corporations to excessive uncertainty and litigation costs.Vice Chancellor Strine makes four fundamental points. First, he notes that while Professors Kahan and Kamar criticize Delaware's current approach as indeterminate, they fail to embrace or flesh out a comprehensive alternative. Second, he points out a contradiction in Kahan and Kamar's argument: under their view, the practical operation of Delaware's corporate law is both a benefit to and a drain on social welfare. Third, he suggests that there are two factors -- divided constituent input and human fallibility -- that better explain the apparent indeterminacy in Delaware corporate law. Finally, Vice Chancellor Strine questions whether Delaware law is overly uncertain or inefficient. He concludes that much of the uncertainty of Delaware's corporate law unavoidably flows from that law's flexibility, which allows economically useful managerial freedom subject to limited judicial intervention to ensure good-faith compliance with fiduciary duties.
Is "Field of Practice" a Relevant Organizing Principle for the MSW Curriculum?.

This article uses data from a national sample of over 2,500 master's degree social workers to examine the relevance of “field of practice” as an organizing principle for the advanced social work cu...
Boolean functions satisfying a higher order strict avalanche criterion

The Strict Avalanche Criterion (SAC) for Boolean functions was introduced by Webster and Tavares in connection with a study of the design of S-boxes. Later Forre extended this notion by defining strict avalanche criteria of order k for Boolean functions of n variables, where 0 ? k ? n - 2; the case k = 0 is the original SAC. Recent work by Lloyd, Preneel and others has been concerned with the problem of counting the functions which satisfy SAC of various orders. If the order is n - 2 or n - 3, this problem has been completely solved; the work in these cases is made easier by the fact that only quadratic Boolean functions occur. In this paper, we give good estimates for the number of Boolean functions which satisfy the SAC of order n - 4. We also give a detailed description of the functions which satisfy SAC of order n - 4, so the actual construction of these functions for cryptographic applications is made easy.
The American Red Cross from Clara Barton to the New Deal

In dark skirts and bloodied boots, Clara Barton fearlessly ventured on to Civil War battlefields to tend to wounded soldiers. She later worked with civilians in Europe during the Franco-Prussian War, lobbied legislators to ratify the Geneva conventions, and founded and ran the American Red Cross. "The American Red Cross from Clara Barton to the New Deal" tells the story of the charitable organization from its start in 1881, through its humanitarian aid during wars, natural disasters, and the Depression, to its relief efforts of the 1930s. Marian Moser Jones illustrates the tension between the organization's founding principles of humanity and neutrality and the political, economic, and moral pressures that sometimes caused it to favor one group at the expense of another. This expansive book narrates the stories of: U.S. natural disasters such as the Jacksonville yellow fever epidemic of 1888, the Sea Islands hurricane of 1893, and the 1906 San Francisco earthquake; crises abroad, including the 1892 Russian famine and the Armenian massacres of 1895-96; efforts to help civilians affected by the civil war in Cuba; power struggles within the American Red Cross leadership and subsequent alliances with the American government; the organization's expansion during World War I; race riots in East St. Louis, Chicago, and Tulsa between 1917 and 1921; help for African American and white Southerners after the Mississippi flood of 1927; and relief projects during the Dust Bowl and after the New Deal. An epilogue relates the history of the American Red Cross since the beginning of World War II and illuminates the organization's current practices as well as its international reputation.
IFRS, U.S. GAAP, and XBRL Financial Statements: An Introduction and Case Study

ABSTRACT Given (a) the mandate to fully comply with “Interactive Data to Improve Financial Reporting,” (Rule 33-2009; SEC 2009b) which requires all SEC registered companies to include financial statements in XBRL format as exhibits with their quarterly or annual reports on a phased-in schedule, and (b) initiations to converge U.S. GAAP and IFRS, it is crucial for students to understand the methodological differences between XBRL financial reporting for these two standards. Therefore, the goal of this case is to expose students to the IFRS and U.S. GAAP XBRL taxonomies. We use the case of a hypothetical company to first illustrate some of the differences between IFRS and U.S. GAAP reporting at the financial statement level, then map its Income Statement line items into respective XBRL taxonomies, and finally create an XBRL instance document. The case provides two exercises to explain the steps in creating an XBRL instance document for different taxonomies, i.e., accessing and then mapping line items into t...
A simple turbulence model for stably stratified wall-bounded flows

In this study, we present a simple zero-equation (algebraic) turbulence closure scheme as well as the standard k-ϵ model for stably stratified wall-bounded flows. We do this by proposing a parameterization for the turbulent Prandtl number (Prt) for stably stratified flows under the influence of a smooth solid wall. The turbulent Prandtl number is the linking bridge between the turbulent momentum and scalar fluxes in the context of Reynolds-averaged Navier-Stokes (RANS) simulations. Therefore, it is important to use appropriate parameterizations for Prt in order to define the right level of momentum and scalar mixing in stably stratified flows. To date, most of the widely used parameterizations for Prt in stably stratified flows are based on data obtained from homogeneous shear flows experiments and/or direct numerical simulations (i.e., statistics are invariant under translations) and are usually formulated as functions of the gradient Richardson number (Rig). The effect of the wall boundary is completely neglected. We introduce a modified parameterization for Prt that takes into account the inhomogeneity caused by the wall coupled with the effects of density stratification. We evaluate the performance of the modified Prt by using a zero-equation turbulence model for the turbulent viscosity that was proposed by Munk and Anderson (1948) as well as the standard k-ϵ model to simulate a one-dimensional stably stratified channel flow. Comparison of the one-dimensional simulation results with direct numerical simulation (DNS) of stably stratified channel flow results show remarkable agreement.
Performance of FDDI in parallel processing systems

Investigates the use of the Fiber Distributed Data Interface (FDDI) as a solution to the problem of interconnecting processing elements in a homogeneous processing environment. The authors present a detailed description of FDDI and compare the communication performance to that of the following topologies: the spanning multiaccess channel hypercube (SMCH), the generalized hypercube (GHC), the nearest neighbor mesh hypercube (NNMH), the Boolean cube (BC), and the cube connected cycles (CCC). It is concluded that, based on the communication performance of the networks, FDDI can be considered as an inexpensive solution to the problem of interconnecting smaller networks for applications which are computationally extensive. >
Vesicular-arbuscular mycorrhizae of epiphytic and terrestrial Piperaceae under field and greenhouse conditions

We examined the roots of 27 epiphytic and terrestrial species of Piperaceae collected in primary and secondary habitats in Monteverde, Costa Rica. Terrestrial roots of only two of the nine Peperomia species, two of eight Piper species, and of Pothomorphe umbellatum contained internal vesicles and/or arbuscules. We did not find internal vesicles and/or arbuscules in 3024 cm of fine roots of epiphytic Piperaceae, even though 15% of these root segments had associated external typical glomalean hyphae. Glomus and Acaulospora spores, and Gigaspora auxiliary cells occurred in both canopy and terrestrial habitats. After inoculation of a low nutrient substrate, the facultatively epiphytic Peperomia costaricensis averaged 23% mycorrhizal root length. Relatively high atmospheric inputs of dissolved inorganic nutrients that alleviate the requirement for mycorrhizae, and heterogeneity of mycorrhiza inocula in the canopy may explain the absence of mycorrhizae from epiphytic Piperaceae. We suggest that the Piperaceae comprises predominantly facultatively mycotrophic species, and that facultative mycotrophism facilitates their radiation to the canopy.
Retinal rods and cones have distinct G protein beta and gamma subunits

Guanine nucleotide-binding proteins (G proteins) involved in transmembrane signal-transduction processes are heterotrimers composed of alpha, beta, and gamma subunits. The alpha subunit shows great diversity and is thought to confer functional specificity to a particular G protein. By contrast, the beta and gamma subunits appear much less diverse; in particular, the beta subunit is believed to have no role in G protein specificity. Using immunocytochemistry, we found distinct distribution patterns for different beta and gamma subunits in the retina. In particular, rod and cone photoreceptors, which both subserve phototransduction but differ in light-response properties, have different beta and gamma subunits in their outer segments. Thus, the G protein mediating phototransduction shows cell-specific forms of the beta and gamma subunits in addition to the alpha subunit. This surprising finding supports the hypothesis that these subunits may also contribute to functional specificity of a G protein.
Molecular Biology in Medicine: The Polymerase Chain Reaction: The Revolution Within

This article has attempted to review the basic and more sophisticated applications of the PCR to modern molecular biology research strategies. It is an inherently powerful tool which has immediately impacted research methodology. But it is equally elegant in its theoretical simplicity and it is this quality that will not simply enhance the means to answer research questions, but effect profound and lasting transformations on the basic nature of the questions themselves. This is where the revolution begins.
Pair debugging: a transactive discourse analysis

Previous research on the interaction between pairs suggests there is a positive relationship between transactive discussion and effective problem solving. Debugging is particularly problematic for novice programmers. Some previous studies suggest this difficulty may be lessened by working in pairs. Using transactive analysis, we examined interactions between five pairs of university-level introductory programming students as they debugged Java programs. Transcriptions of their verbal interactions were coded into transactive statement categories which revealed that the nature of participants' discourse varied. Extensions, feedback requests, critiques and completions were the most frequently observed types of transactions. Other transaction types were rarely detected in this context. The amount of discussion for the pairs varied as did the number of transactive statements. Results suggest that pairs who talked more and used completion transactions more often attempted more problems, but those who critiqued more frequently successfully debugged more problems. The teaching implications of this work and recommendations for future research are discussed.
Absolute phase-assisted three-dimensional data registration for a dual-camera structured light system

For a three-dimensional shape measurement system with a single projector and multiple cameras, registering patches from different cameras is crucial. Registration usually involves a complicated and time-consuming procedure. We propose a new method that can robustly match different patches via absolute phase without significantly increasing its cost. For y and z coordinates, the transformations from one camera to the other are approximated as third-order polynomial functions of the absolute phase. The x coordinates involve only translations and scalings. These functions are calibrated and only need to be determined once. Experiments demonstrated that the alignment error is within RMS 0.7 mm.
Isoenzymes in Clinical Diagnosis

The recent literature attests to the increasing number of enzymes for which isoenzymes or subunit structure or both are known. Several symposia and reviews have been published within the past few years.46-50 Some enzyme activities for which isoenzymes have been described are listed in table 4. Only those found in mammals are included. They are ranked in rough order of apparent usefulness in clinical diagnosis, with the enzymes displaying tissue localization and catalytic differences listed first. Also, the number of molecular forms and the presence or absence of known subunit structure is indicated. Clinical studies have been made using several of the isoenzymes listed in table 4, and references denoting these studies are marked with an asterisk. Data presented in the table indicate that valuable clinical information might derive from study of other isoenzymes, notably phosphofructokinase, for which tissue differences and adaptable catalytic differences exist. The guidelines set forth in this review can b...
The relationship between differentiating medulloblastoma and dedifferentiating diffuse cerebellar astrocytoma. Light, electron microscopic, tissue, and organ culture observations.

Light, electron microscopic, and tissue and organ culture observations are reported on an unusual example of cerebellar and brainstem glioma in a 14-year-old girl, which showed the concomitant picture of diffusely infiltrating astrocytoma and focal medulloblastoma. Although the in vitro studies on this neoplasm demonstrated progressive differentiation from primitive medulloblastoma cells into astrocytes rich in glial filaments, the tumor as a whole was interpreted as an exceptional case of diffuse cerebellar astrocytoma dedifferentiating into medulloblastoma. The reasons for this interpretation are given, and the case is discussed in the light of the controversial views regarding the differentiating capabilities of the medulloblastoma.
Effects of low frequency electromagnetic fields on the activity of ornithine decarboxylase in developing chicken embryos

Abstract In another paper we have reported the results of a study involving over 2500 chick embryos, in which time-varying magnetic fields (MFs) were shown to induce morphological abnormality. In an attempt to understand the mechanism by which these abnormalities arise, the present work explores the effects of weak magnetic fields (MFs) on the activity of the growth related enzyme ornithine decarboxylase (ODC) in chick embryos. The results presented here demonstrate that a 4 μT, 60 Hz sinusoidal magnetic field significantly enhances ODC activity during gastrulation, and diminishes ODC activity during neurulation. In another set of experiments, slightly older embryos were analyzed for gross morphology. The abnormality rate among MF-exposed embryos was approximately three times that of control embryos — with the vast majority of malformations being neural tube abnormalities. When embryos with morphological abnormalities were assayed separately from those which were morphologically normal, it was found that the ODC activity in the abnormal group was significantly less than that in the normal group. However, comparison of normal control embryos with normal MF exposed embryos showed no differences in ODC activity. Similarly comparison of abnormal control embryos with abnormal MF-exposed embryos showed no differences in the ODC activity. We speculate that MF-induced ODC alterations during neurulation may be related to the occurrence of MF-induced neural tube abnormalities at later stages of development.
Predicted and experimental structures of integrins and β-propellers

Integrins and other cell surface receptors have been fertile grounds for structure prediction experiments. Recently determined structures show remarkable successes, especially with beta-propeller domain predictions, and also reveal how ligand binding by integrins is conformationally regulated.
Properties and regulation of liver phosphorylase phosphatase

Abstract A procedure was developed for the isolation of rabbit liver phosphorylase phosphatase. The properties of a preparation made by this procedure were examined. The enzyme had a molecular weight of 35,000, and was shown to behave as a protein phosphatase in that glycogen synthase and histones were also substrates. An activation phenomenon encountered during the development of the purification procedure was studied. Both ethanol and trypsin treatment lead to the activation and concomitant interconversion of enzyme activity in liver extracts from apparent multiple molecular weight forms to a single smaller form of M.W. 35,000. It was proposed that the enzyme exists in an inactive form(s) consisting of complexes of the M.W. 35,000 enzyme with protein inhibitors. The properties of a preparation of an endogenous rabbit liver protein inhibitor were examined and found to be consistent with this explanation. Furthermore, evidence was found for a single inactive form of the enzyme (M.W. 220,000) from which the multiple forms may be artifactually derived during homogenization. On the basis of these studies we have proposed a model for the relationship between the active and inactive forms of the enzyme, and the possible regulation of this interconversion. While a great deal of further investigation is needed to establish the true nature and regulation of the protein phosphatases, their elucidation is clearly fundamental to our understanding of the molecular mechanisms of the regulation of glycogen metabolism.
Order in metallic chains. II. Coupled chains

The possibility of long-range order in a quasi-one-dimensional metal is studied from the standpoint of the two existing exactly soluble models of the interacting electron gas in one dimension. The presence of interchain low-momentum-transfer electron-electron interactions does not give rise to a phase transition of any type but serves only to renormalize the effective intrachain interactions. In the region of the space of intrachain interactions for which the purely one-dimensional charge-density wave response function is divergent as $T\ensuremath{\rightarrow}0$, the presence of nearest-neighbor interchain large-momentum-transfer electron-electron scattering gives rise to a phase transition only of the charge-density-wave type. When the electronic motion is not restricted to one spatial dimension, phase transitions of either the singlet superconducting or charge-density-wave type may occur, depending upon the effective intrachain interactions. These phase transitions are investigated in the "mean-field" and "self-avoiding random-walk" approximations, and the effects of fluctuations in the interchain couplings are found to be small.
Theory and inference for regression models with missing responses and covariates

In this paper, we carry out an in-depth theoretical investigation for inference with missing response and covariate data for general regression models. We assume that the missing data are missing at random (MAR) or missing completely at random (MCAR) throughout. Previous theoretical investigations in the literature have focused only on missing covariates or missing responses, but not both. Here, we consider theoretical properties of the estimates under three different estimation settings: complete case (CC) analysis, a complete response (CR) analysis that involves an analysis of those subjects with only completely observed responses, and the all case (AC) analysis, which is an analysis based on all of the cases. Under each scenario, we derive general expressions for the likelihood and devise estimation schemes based on the EM algorithm. We carry out a theoretical investigation of the three estimation methods in the normal linear model and analytically characterize the loss of information for each method, as well as derive and compare the asymptotic variances for each method assuming the missing data are MAR or MCAR. In addition, a theoretical investigation of bias for the CC method is also carried out. A simulation study and real dataset are given to illustrate the methodology.
Plant biotechnology and developing countries

Over the next half century, crop production in developing countries must more than double. Plant biotechnology, applied through the international agricultural research system, can help to ensure that the necessary increases in production are achieved, that they are sustainable and that they will benefit the vast majority of food producers and consumers in developing countries with limited purchasing power.
Vascular dynamics and BOLD fMRI: CBF level effects and analysis considerations

Abstract Changes in the cerebral blood flow (CBF) baseline produce significant changes to the hemodynamic response. This work shows that increases in the baseline blood flow level produce blood oxygenation-level dependent (BOLD) and blood flow responses that are slower and lower in amplitude, while decreases in the baseline blood flow level produce faster and higher amplitude hemodynamic responses. This effect was characterized using a vascular model of the hemodynamic response that separated arterial blood flow response from the venous blood volume response and linked the input stimulus to the vascular response. The model predicted the baseline blood flow level effects to be dominated by changes in the arterial vasculature. Specifically, it predicted changes in the arterial blood flow time constant and venous blood volume time constant parameters of +294% and −24%, respectively, for a 27% increase in the baseline blood flow. The vascular model performance was compared to an empirical model of the hemodynamic response. The vascular and empirical hemodynamic models captured most of the baseline blood flow level effects observed and can be used to correct for these effects in fMRI data. While the empirical hemodynamic model is easy to implement, it did not incorporate any explicit physiological information.
Nectar Resources and Their Influence on Butterfly Communities on Reclaimed Coal Surface Mines

Despite the critical role insects play in ecosystem functioning, there has been little study of factors affecting their reestablishment in restored ecosystems. The goals of this research were to quantify the nectar resources provided by reclaimed coal surface mines and to examine the role nectar resources play in determining butterfly community composition on these sites. Adult butterfly communities and nectar resources were sampled on 18 reclaimed coal surface-mined sites and five unmined hardwood sites in southwestern Virginia. Recently, reclaimed sites provided an average of 300 times the nectar abundance of the surrounding hardwoods, and nectar abundance and species richness decreased with time since reclamation. Total nectar abundance was highly correlated with total butterfly abundance and species richness for the entire flight season; these variables were also significantly correlated among sites during most of the 12 sampling periods during the flight season. In only a few cases, however, were butterfly and nectar abundance and species richness significantly correlated within individual sites during the flight season. These results suggest that, although adults of many butterfly species move in response to nectar availability, nectar resources are not sufficiently limiting that their life histories have evolved to maximize nectar resources temporally. While planting species in restored areas that provide abundant nectar will likely attract adult butterflies, this is only one of a number of habitat variables that must be considered in efforts to restore butterfly populations. Finally, adult butterflies appear to have limited utility as indicators of revegetation success.
Cell types in cutaneous type I mechanoreceptors (Haarscheiben) and their alterations with injury

Type I mechanoreceptors (also called Haarscheiben or “domes”) are small elevations on the cat's skin, each being supplied by a myelinated sensory fiber. The fiber terminates in apposition to specialized receptor cells (Merkel cells) lying at the base of the epithelium investing the structure. When a group of domes was injured some of the neighboring domes became structurally altered as determined by light and electron microscopy. The changes observed resembled those which accompany denervation and involved the loss of Merkel cells and their apposed sensory nerve terminals from the dome. Since this trauma was produced indirectly it has been called secondary injury. Cells showing some of the morphological features of both keratin-producing epithelial cells and Merkel cells were observed in secondarily injured domes and in non-injured domes. The presence of such transitional cells suggests that Merkel cells may be derived from keratinocytes.
Properties and structure of fractions prepared from Anabaena variabilis by the action of Triton X-100

Abstract Treatment of Anabaena variabilis with sonic oscillation produces green membrane fragments which are derived from the photosynthetic system. Further treatment of these fragments with Triton X-100 produces two additional fragments, a blue heavy (H) and an orange light (L) fragment, which are separable by sucrose density gradient centrifugation. Although both the physiological reactions related to photosynthesis (NADP + photoreduction and O 2 evolution) are missing from these derived particles, physical and biochemical evidence allows an identification of the two fragments. P700 is localized in the H fragment. Fluorescence spectra at room and liquid N 2 temperature, as well as P700 response, show that the H fragment is related to Photosystem 1 and the L fragment is derived from Photosystem 2. On the basis of chlorophyll content the concentrations of carotenoids, lipid and protein are higher in the L fragment, while the ratio of β-carotene to total xanthophylls is higher in the H fragment. Of the total chlorophyll, a , 80% is found in the H fragment. The electron micrographs of these fragments show that the H fragment consists of flat discs 0.1–0.3 μ in diameter on which many small 100-A particles are present, while the L fragment consists of small membrane fragments and irregular stranded material 50–60 A in width.
Electron microscopy of human serum lipoproteins using negative staining

Abstract Human serum lipoproteins were separated by ultracentrifugation into 3 fractions: high density lipoproteins, low density lipoproteins, and very low density lipoproteins including chylomicrons. The structures of the various fractions were studied with the electron microscope after negative staining with sodium phosphotungstate. The high density lipoproteins appear to be structures 86 A in average diameter possessing an electron-dense central region. The lipoproteins are composed of subunits which in some cases appear to be elongated with an estimated short axis of 36 A and long axis of 64 A. The high density lipoproteins may further be fractionated into their subclasses, HDL2 and HDL3. The HDL3 molecules are considerably smaller in average diameter (65 A) than the HDL2 (95 A). The low density lipoproteins appear spherical with a mean diameter of 216 A and they display a high degree of deformability, but they have no visible subunit structures. Bridge-like connections between adjacent lipoproteins also appear to be present. The very low density lipoproteins plus chylomicrons are extremely heterogeneous in size and shape and range from 230–5000 A in diameter. The smaller molecules seem to be spherical while the extremely large ones are flattened and irregular in shape. There is no apparent substructure either within or at the periphery of these particles.
Concentrations and stable isotope values of BTEX in gasoline-contaminated groundwater

This work was undertaken to investigate the usefulness of stable carbon isotopic analysis as a monitoring tool for contaminant remediation. Concentrations and δ13C values of BTEX (benzene, toluene, ethylbenzene, and xylenes) were measured at a gasoline-contaminated site in southern California. The BTEX data were determined using a purge-and-trap connected to a gas chromatograph/ion trap mass spectrometer and to an isotope ratio mass spectrometer system. Concentrations ranged from below detection (<0.5 ppb ≈ 0.05 μM C) to about 120 ppm (≈10 000 μM C) total BTEX, with toluene generally having the highest concentrations. For BTEX compounds at monitoring wells averaged across all sampling dates, δ13C values ranged from −23.8 to −26.6‰ (benzene), −22.9 to −25.2‰ (toluene), from −23.0 to −25.3‰ (p&m-xylenes), and from −22.4 to −25.0‰ (o-xylene). The data strongly suggest two sources of contamination: one with lighter (12C-enriched) δ13C values emanating from the area near monitoring wells 1 and 2, and the othe...
A new, safer lasing technique for laser-facilitated coronary angioplasty.

In vitro studies during cold pulsed-wave laser angioplasty have demonstrated production of gas bubbles within the target tissue, creation of shock wave and formation of multi-layer dissections accompanied by an increase in the plaque and vessel wall temperature. These processes account for certain complications of coronary lasing, including acute vessel closure, dissections, spasm, and even perforation. The traditional lasing technique in which a large number of pulses is continually emitted across the lesion, may in fact contribute to the development and acceleration of the above mentioned processes. To overcome the shortcomings we have developed a new, safe lasing technique that consists of multiple trains of a small number of pulses each. Between laser sessions the laser catheter is retracted into the guiding catheter and nitroglycerin is injected intracoronary, thus providing time for dispersion of produced gas bubbles, cooling of the target artery, and adequate coronary vasodilatation. This new technique results in a significant reduction of laser associated complications. (J Interven Cardiol 1993; 6:297–306)
Hypocholesterolemic agent compactin. an alternative diels-alder strategy for the synthesis of the hexahydronaphthalene portion

The synthesis of the hexahydronaphthalene segment (4) of compactin (1) has been accomplished in a short sequence (8 steps from 9) featuring the intramolecular Diels-Alder cycloaddition of 7b.
Input substitution, economies of scale and productivity growth in the US upholstered furniture industry

Cost, factor demand and productivity growth are considered in the upholstered furniture industry over 1958–87. Factors are divided into labour, capital and materials. It is found that all inputs are substitutes in production although substitution elasticities are small. Factor demand is price-inelastic for all inputs. The industry operates around minimum average cost. Productivity growth is small but significant. The results indicate that labour will continue to be important in the industry. However, regional comparative advantage is not related to labour alone; the results suggest that policies to attract or retain the industry must consider the low degree of factor substitution.
Dissecting aneurysm of the aorta

Abstract The clinical aspects and the post-mortem observations in 19 cases of dissecting aneurysm of the aorta are described. Clinically, these patients presented (1) old dissections, with intractable heart failure, which had (a) a “silent” history and course in regard to the dissection, or (b) an active history and course, with repeated attacks of severe pain in the chest that radiated into the neck and back; and (2) recent dissections with (a) a typical onset of pain or collapse and (b) an atypical onset with severe dyspnea. Physical signs of a variable character, such as cardiac murmurs, were outstanding, and did not conform to any definite pattern. The majority of patients with dissecting aneurysm of the aorta do not have a typical onset or course; the latter may extend over many months, but at some time present any or all of the physical signs which have been discussed.
Metabolomics annotates ABHD3 as a physiologic regulator of medium-chain phospholipids

All organisms, including humans, possess a huge number of uncharacterized enzymes. Here we describe a general cell-based screen for enzyme substrate discovery by untargeted metabolomics and its application to identify the protein α/β-hydrolase domain-containing 3 (ABHD3) as a lipase that selectively cleaves medium-chain and oxidatively truncated phospholipids. Abhd3(-/-) mice possess elevated myristoyl (C14)-phospholipids, including the bioactive lipid C14-lysophosphatidylcholine, confirming the physiological relevance of our substrate assignments.
Spatial persistence and sediment disturbance of an arenicolid polychaete

Field evidence suggests that biogenic sediment movement influences the distribution of infauna but also that biogenic processes account for only a small proportion of total sediment movement. This difference may be due to biogenic additions to the sediment or the mode of biogenic vs. physical deposition or to calculation of the biogenic effect as inappropriately scaled temporal and spatial averages. Spatial persistence of biogenic effects over time would bias such averages. Individuals of the arenicolid polychaete Abarenicola pacijca can be sized and mapped by the diameter and position respectively of their fecal coils. Their spatial distributions show significant clumping. Both individuals of A. pacifica and their biogenically disturbed patches have considerable spatial persistence over time. Individuals remained in the same spatial location for up to 12 d. Over 50% of all patches of biogenic sediment disturbance persisted for at least the 16-d observation period, and the patches were highly localized. Thus spatial and temporal averages may be inappropriate for determining the importance of biogenic effects, due to nonuniform distribution of individuals and their spatial and temporal persistence. A common phenomenon in sedimentary environments is biogenic alteration of the sediments by infauna, including defecation, burrowing, tube building, feeding, and irrigation. In some habitats biogenic alterations affect the erodibility of the sediments (Luckenbach 1986; Meadows and Tait 1989), the distributions of grain sizes (Rhoads and Stanley 1965), and the concentrations of pore-water constituents (Aller 1982). Biogenic alterations also can affect the distributions of the infauna. For example, burrowing and defecation can affect infaunal recruitment patterns (Wilson 198 1; Posey 1986; Smith et al. 1986); infaunal secretions can alter the chemical constituents of the sediment (Ring 1986; Woodin et al. 1987), potentially affecting patterns of recruitment (Highsmith 1982; Woodin 199 l), and biogenic structures can alter the ability of individuals to burrow through the sediment (Ronan 1975; ’ Corresponding author.
Psychometric Properties of the Brief Fatigue Inventory in Community-Dwelling Older Adults

Objective To investigate the psychometric properties of the Brief Fatigue Inventory (BFI) in community-dwelling older adults.