cssi/SciSciGPT-SciSciNet huggingface dataset:
SNP‐based heritability and genetic architecture of tarsal osteochondrosis in North American Standardbred horses

Osteochondrosis is a common developmental orthopedic disease characterized by a failure of endochondral ossification. Standardbred horses are recognized as being predisposed to tarsal osteochondrosis. Prior heritability estimates for tarsal osteochondrosis in European Standardbreds and related trotting breeds have been based on pedigree data and range from 17-29%. Here, we report on genetic architecture and heritability based on high-density genotyping data in a cohort of North American Standardbreds (n = 479) stringently phenotyped for tarsal osteochondrosis. Whole-genome array genotyping data were imputed to ~2 million single nucleotide polymorphisms (SNPs). SNP-based heritability of osteochondrosis in this population was explained by 2326 SNPs. The majority of these SNPs (86.6%) had small effects, whereas fewer SNPs had moderate or large effects (10% and 2.9% respectively), which is consistent with a polygenic/complex disease. Heritability was estimated at 0.24 ± 0.16 using two methods of restricted maximum likelihood analysis, as implemented in gcta (with and without a weighted relatedness matrix) and ldak software. Estimates were validated using bootstrapping. Heritability estimates were within the range previously reported and suggest that osteochondrosis is moderately heritable but that a significant portion of disease risk is due to environmental factors and/or genotype × environment interactions. Future identification of the genes/variants that have the most impact on disease risk may allow early recognition of high-risk individuals.
A 104.8TOPS/W One-Shot Time-Based Neuromorphic Chip Employing Dynamic Threshold Error Correction in 65nm

As neural networks continue to infiltrate diverse application domains, computing will begin to move out of the cloud and onto edge devices necessitating fast, reliable, and low power solutions. To meet these requirements, we propose a time-domain core using one-shot delay measurements and a lightweight post-processing technique, Dynamic Threshold Error Correction (DTEC). This design differs from traditional digital implementations in that it uses the delay accumulated through a simple inverter chain distributed through an SRAM array to intrinsically compute resource intensive multiply-accumulate (MAC) operations. Implemented in 65nmLP CMOS we achieve, to our knowledge, the lowest reported energy efficiency for a neuromorphic processor with 52.4TSOp/s/W (104.8TOp/S/W) at 0.7V with 3b resolution for an impressive 19.1fJ/MAC.
Food Activity Footprint: Dominican Women’s Use of Time and Space for Food Procurement

Understanding the influence of the food environment on eating behaviors is important for addressing spatial health disparities. This research aimed to understand how Dominican-born women living in ...
CorTiS: Correlation-Based Time Synchronization in Internet of Things

Efficient and accurate time synchronization is critical to various applications in the Internet of Things and has been extensively studied. The emergence of large-scale, duty-cycled sensor networks ruins the previous assumptions used for protocol design, leading to the necessity of developing new synchronization protocols to achieve better energy efficiency and reliability. In this paper, the correlation-based time synchronization protocol (CorTiS), which exploits the spatiotemporal correlation between clocks, is developed. To the best of our knowledge, this is the first effort that exploits spatiotemporal correlation for time synchronization. A theoretical spatiotemporal model is presented to capture the collective behaviors of clocks. With this model, a probabilistic prediction scheme to infer synchronization errors based on correlation is developed without additional message exchanges. The CorTiS protocol is then developed incorporating community detection technique to cluster clocks that are tightly correlated as synchronization communities, such that different communities can be adaptively synchronized. Simulation results show that with CorTiS, participating nodes in each synchronization round can be significantly reduced in dynamic environments.
Read/Interrogation Enhancement of Chipless RFIDs Using Machine Learning Techniques

This letter describes the implementation of a machine learning (ML) classification strategy for read/interrogation enhancement in chipless radio frequency identification (RFID) applications. A novel ML-based approach for classification and of detection tag identifications (IDs) has been presented, which can perform effective transponder readings for a wide variety of ranges and contexts, while providing tag-ID detection accuracy of up to 99.3%. Four tags encoding the four 2 bit IDs were inkjet-printed onto flexible low-cost polyethylene terephtalate substrates and interrogated without crosstalk or clutter interference de-embedding at ranges up to 50 cm, with different orientations and with and without the presence of scattering objects in the vicinity of the tags and reader. A support vector machine algorithm was then trained using 816 measurements, and its accuracy was tested and characterized as a function of the included training data. Finally, the excellent performance of the approach, displaying reading accuracies ranging from 89.6% to 99.3%, is reported. This effort sets a precedent, opening the door to a rich and wide area of research for the implementation of ML methods for the enhancement of chipless RFID applications.
A novel anthropomorphic multimodality phantom for MRI-based radiotherapy quality assurance testing.

Purpose Increased utilization of magnetic resonance imaging (MRI) in radiotherapy has caused a growing need for phantoms that provide tissue-like contrast in both computed tomography (CT) and MRI images. Such phantoms can be used to compare MRI-based processes with CT-based clinical standards. Here, we develop and demonstrate the clinical utility of a three-dimensional (3D)-printed anthropomorphic pelvis phantom containing materials capable of T1 , T2 , and electron density matching for a clinically relevant set of soft tissues and bone. Methods The phantom design was based on a male pelvic anatomy template with thin boundaries separating tissue types. Slots were included to allow insertion of various dosimeters. The phantom structure was created using a 3D printer. The tissue compartments were filled with carrageenan-based materials designed to match the T1 and T2 relaxation times and electron densities of the corresponding tissues. CT and MRI images of the phantom were acquired and used to compare phantom T1 and T2 relaxation times and electron densities to literature-reported values for human tissue. To demonstrate clinical utility, the phantom was used for end-to-end testing of an MRI-only treatment simulation and planning workflow. Based on a T2 -weighted MRI image, synthetic CT (sCT) images were created using a statistical decomposition algorithm (MRIPlanner, Spectronic Research AB, Sweden) and used for dose calculation of volumetric-modulated arc therapy (VMAT) and seven-field intensity-modulated radiation therapy (IMRT) prostate plans. The plans were delivered on a Truebeam STX (Varian Medical Systems, Palo Alto, CA), with film and a 0.3 cc ion chamber used to measure the delivered dose. Doses calculated on the CT and sCTs were compared using common dose volume histogram metrics. Results T1 and T2 relaxation time and electron density measurements for the muscle, prostate, and bone agreed well with literature-reported in vivo measurements. Film analysis resulted in a 99.7% gamma pass rate (3.0%, 3.0 mm) for both plans. The ion chamber-measured dose discrepancies at the isocenter were 0.36% and 1.67% for the IMRT and VMAT plans, respectively. The differences in PTV D98% and D95% between plans calculated on the CT and 1.5T/3.0 T-derived sCT images were under 3%. Conclusion The developed phantom provides tissue-like contrast on MRI and CT and can be used to validate MRI-based processes through comparison with standard CT-based processes.
Epigenetic dynamics in cancer stem cell dormancy

Cancer remains one of the most challenging diseases despite significant advances of early diagnosis and therapeutic treatments. Cancerous tumors are composed of various cell types including cancer stem cells capable of self-renewal, proliferation, differentiation, and invasion of distal tumor sites. Most notably, these cells can enter a dormant cellular state that is resistant to conventional therapies. Thereby, cancer stem cells have the intrinsic potential for tumor initiation, tumor growth, metastasis, and tumor relapse after therapy. Both genetic and epigenetic alterations are attributed to the formation of multiple tumor types. This review is focused on how epigenetic dynamics involving DNA methylation and DNA oxidations are implicated in breast cancer and glioblastoma multiforme. The emergence and progression of these cancer types rely on cancer stem cells with the capacity to enter quiescence also known as a dormant cellular state, which dictates the distinct tumorigenic aggressiveness between breast cancer and glioblastomas.
Resilience and Vulnerabilities of the North American Food System during the Covid‐19 Pandemic

The coronavirus pandemic and consequent economic disruption have tested the resilience of the North American food system. The poorest Americans were put at risk of food deprivation as their incomes fell. Disruptions reverberated through the food supply chain as the pandemic escalated; meatpacking plants became disease hotspots. The Coronavirus Food Assistance Program (CFAP) provided US$ 16 billion of aid to farmers and ranchers based on falling prices. CFAP added to the counter-cyclical safety-net programmes legislated in 2018 and ad hoc support authorised for two years by the Trump administration. The CFAP support is reasonable in the context of the pandemic-related economic collapse, but also raises concern about increased support tied to market conditions and current production, including support linked to unilateral US trade policies that have invoked retaliation by trading partners. As of early June, the hopeful scenario was that the worst challenges to the food system had passed. Grain and livestock inventories were relatively high and spring planting intentions were strong, but supply constraints in North America or internationally remained a risk. The pandemic has underscored the inherent fragility of an integrated world and the high stakes in the debate about globalisation that will inevitably follow.
Characterization hiPSC-derived neural progenitor cells and neurons to investigate the role of NOS1AP isoforms in human neuron dendritogenesis.

Abstract Abnormal dendritic arbor development has been implicated in a number of neurodevelopmental disorders, such as autism and Rett syndrome, and the neuropsychiatric disorder schizophrenia. Postmortem brain samples from subjects with schizophrenia show elevated levels of NOS1AP in the dorsolateral prefrontal cortex, a region of the brain associated with cognitive function. We previously reported that the long isoform of NOS1AP (NOS1AP-L), but not the short isoform (NOS1AP-S), negatively regulates dendrite branching in rat hippocampal neurons. To investigate the role that NOS1AP isoforms play in human dendritic arbor development, we adapted methods to generate human neural progenitor cells and neurons using induced pluripotent stem cell (iPSC) technology. We found that increased protein levels of either NOS1AP-L or NOS1AP-S decrease dendrite branching in human neurons at the developmental time point when primary and secondary branching actively occurs. Next, we tested whether pharmacological agents can decrease the expression of NOS1AP isoforms. Treatment of human iPSC-derived neurons with d -serine, but not clozapine, haloperidol, fluphenazine, or GLYX-13, results in a reduction in endogenous NOS1AP-L, but not NOS1AP-S, protein expression; however, d -serine treatment does not reverse decreases in dendrite number mediated by overexpression of NOS1AP isoforms. In summary, we demonstrate how an in vitro model of human neuronal development can help in understanding the etiology of schizophrenia and can also be used as a platform to screen drugs for patients.
Balancing risk and reward: mating opportunity influences thermal refuge use in fiddler crabs

Behavioural thermoregulation can ameliorate thermal stress but is costly. For species that court in a thermally stressful microhabitat, sexual selection via endurance rivalry favours individuals that are able and willing to endure harsh conditions in the courtship habitat, as retreats to a thermal refuge will reduce mating opportunities. The relative costs and benefits of refuge use versus continued courtship in the face of thermal risk, which vary across abiotic and biotic contexts, determine the optimal behavioural strategy. We examined the social and abiotic factors driving behavioural decisions related to thermoregulatory retreat in the fiddler crab Austruca mjoebergi. Male fiddler crabs perform a courtship display on the thermally stressful intertidal sediment surface. Time on the surface, and thus time available for display, was limited by high temperatures; as temperature increased, surface time decreased. Yet when presented with a stimulus female, males were more likely to perform the courtship display, displayed at a higher rate and increased time spent on the surface. These results demonstrate that behavioural decisions related to thermal retreat depend both on the abiotic conditions that influence the degree of thermal stress and on the social conditions that influence the reproductive prospects of the individual.
Management of Cervico-Cranial Arterial Dissections

Cervico-cranial arterial dissections are a distinct etiology of both ischemic and hemorrhagic neurovascular events. These dissections can involve the extracranial carotid or vertebral arteries, classified collectively as cervical artery dissections, or can be intracranial arterial dissections, and complications and management of each differ. The most recent evidence is reviewed in this publication. Significant heterogeneity regarding treatments of dissections exists among providers and with recent advances in endovascular approaches to neurovascular care, appreciating the latest evidence on the guidance of treatment has never been so challenging. Furthermore, recognizing the complications of cervico-cranial dissections and implementing appropriate therapies can have a significant impact on patient outcomes. Overall, limited randomized controlled data exists regarding the treatment of cervico-cranial dissections. Approach to management of these dissections and potential complications is largely based on observational studies and reported cases. The available evidence and strength vary depending on the case and complication.
Hypoglossal nerve stimulation impact on a patient with obstructive sleep apnea and heart failure.

A 75-year-old man with body mass index of 30.5 kg/m2 and severe obstructive sleep apnea (OSA) with an apnea-hypopnea index (AHI) of 72 events/h was referred for upper airway stimulation (UAS) thera...
Are Serious Games a Good Strategy for Pharmacy Education

Serious gaming is the use of game principles for the purposes of learning, skill acquisition, and training. Higher education is beginning to incorporate serious gaming into curricula, and health professions education is the most common area for serious game use. Advantages of serious gaming in pharmacy education include authentic, situated learning without risk of patient consequences, collaborative learning, ability to challenge students of all performance levels, high student motivation with increased time on task, immediate feedback, ability to learn from mistakes without becoming discouraged, and potential for behavior and attitude change. Development of quality games for pharmacy education requires content expertise as well as expertise in the science and design of gaming. When well done, serious gaming provides a valuable additional tool for pharmacy education.
Briefs and Contracts in Plain English

Lawyers, judges, and law professors sometimes vaguely recommend that briefs and contracts "should be written in Plain English." But what does that mean? And is plain English right for all briefs and contracts? This article defines plain English as a form of legal writing intended for nonlawyers and encourages lawyers to be more precise in recommending plain English--and plain-English principles. (Includes several typical legal text in before-and-after form.)
Gender and Migration Scholarship: An Overview from a 21st Century Perspective

Gender and migration research has grown vastly in the last thirty years, but where does it stand today, at the outset of the twenty­first century? Much of immigration scholarship shows continuing androcentric blind­ness to feminist issues and gender (Morakvasic, 1984; Pe­draza, 1991). That’s old news, but it’s still true. That, howev­er, is not the story that I narrate here, as today there
Growth Yields of Bacteria on Selected Organic Compounds

Cell yields were determined for two bacterial soil isolants grown aerobically in minimal media on a variety of synthetic organic compounds. 1-Dodecanol, benzoic acid, phenylacetic acid, phenylglyoxylic acid, and diethylene, triethylene, and tetraethylene glycols were tested. Two “biochemicals,” succinate and acetate, were also tested for comparison. Yields were calculated on the basis of grams of cells obtained per mole of substrate utilized, gram atom of carbon utilized, mole of oxygen consumed, and equivalent of “available electrons” in the substrates. This latter value appears to be nearly constant at 3 g of cells per equivalent of “available electrons.” Yields predicted on this basis for other bacteria and for yeasts on other substrates are in fair agreement with reported values.
Signal Transduction in Trypanosoma cruzi

Signal transduction plays a key role in regulating important functions in both multicellular and unicellular organisms and largely controls the manner in which cells respond to stimuli. Signal transduction pathways coordinate the functions in different type of cells in animals and control the growth and differentiation in unicellular organisms. Intracellular signal transduction pathways are largely activated by second messenger molecules. Trypanosoma cruzi has a complex life cycle involving four morphogenetic stages with various second messenger systems able to regulate its growth and differentiation. Signal transduction often alters the status of phosphorylation in target proteins and thus alters the activities of these proteins. In this review, two major signal transduction pathways, cyclic AMP-dependent pathway and mitogen-activated protein kinase pathway, are discussed. Protein phosphatases are also discussed due to their importance in dephosphorylating target proteins and terminating signal transduction. Understanding of the unique pathways in this pathogen may lead to the development of novel therapeutic agents.
Rate-distortion optimization for VBR environments using a motion compensated wavelet coder

This paper presents a motion-compensated wavelet video coder applicable to VBR transmission where constant distortion coding at minimal rate is desired. The R-D optimization is achieved by jointly optimizing the coding parameters in both the variable block size motion estimation and the region-based embedded wavelet coding of the residual. Experiments are performed by matching PSNR profiles from TM5 and by constant distortion coding using the average PSNR from TM5. Results show that visual quality is maintained at a rate reduction of 22%-29%.
A quadrature sinusoidal oscillator with phase-preserving linear frequency control and independent static amplitude control

A G/sub m/-C architecture for a quadrature, sinusoidal oscillator with instantaneous, phase-preserving, linear frequency control and independent, static amplitude control is presented. The architecture is analyzed and closed-form expressions are given for both frequency and amplitude. An implementation of the architecture using general purpose discrete bipolar transistors has been tested. Simulation results and measurements are demonstrated and compared to theory. The wide frequency range of tunability and the low total harmonic distortion observed, as well as the inherent phase preservation make the architecture appropriate for use in analog communication schemes.
Valence Parton Distribution Functions from Quantum ChromoDynamics

We show that two dimensional QCD can, to a good approximation, describe the hadronic structure functions measured in Deep Inelastic Scattering. We transform this theory into a new form, Quantum HadronDynamics (QHD), whose semi-classical approximation is closer to nature. The Baryon is then a topological soliton, and its structure function can be predicted by a variational principle. This prediction can be tested by comparison with measurements of neutrino scattering cross-sections.
Should cell-free DNA testing be used to target antenatal rhesus immune globulin administration?

AbstractObjective: To compare the rates of alloimmunization with the use of cell-free DNA (cfDNA) screening to target antenatal rhesus immune globulin (RhIG) prenatally, versus routine administration of RhIG in rhesus D (RhD)-negative pregnant women in a theoretic cohort using a decision-analytic model.Methods: A decision-analytic model compared cfDNA testing to routine antenatal RhIG administration. The primary outcome was maternal sensitization to RhD antigen. Sensitivity and specificity of cfDNA testing were assumed to be 99.8% and 95.3%, respectively. Univariate and bivariate sensitivity analyses, Monte Carlo simulation, and threshold analyses were performed.Results: In a cohort of 10 000 RhD-negative women, 22.6 sensitizations would occur with utilization of cfDNA, while 20 sensitizations would occur with routine RhIG. Only when the sensitivity of the cfDNA test reached 100%, the rate of sensitization was equal for both cfDNA and RhIG. Otherwise, routine RhIG minimized the rate of sensitization, espe...
t‐Butyl azodiformate

t-Butyl azodiformate solvent: 60 ml. of pyridine intermediate: 23.2 g. (0.1 mole) of crude t-butyl hydrazodiformate solvent: 35–40 ml. of petroleum ether solvent: ligroin product: t-Butyl azodiformate Keywords: acylation; oxidation, NHNH NN
A spinal mechanism of action for duloxetine in a rat model of painful diabetic neuropathy

BACKGROUND AND PURPOSE This study was designed to clarify mechanisms responsible for the anti-allodynic effects of duloxetine in diabetes. EXPERIMENTAL APPROACH The streptozotocin-induced diabetic rat model was used to compare the efficacy of duloxetine, 5-HT, the 5-HT2A receptor agonist [1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI)] and two antagonists (ketanserin and pruvanserin) on tactile allodynia. KEY RESULTS Systemic or intrathecal injection of duloxetine alleviated tactile allodynia in diabetic rats. The effect of systemic duloxetine was reduced by intrathecal administration of ketanserin or pruvanserin, indicating participation of spinal 5-HT2A receptors in the mechanism of action of duloxetine. In contrast to spinal delivery, systemic and local peripheral injections of ketanserin or pruvanserin alleviated tactile allodynia in diabetic rats. This effect was reversed immediately after systemic or local DOI injection. CONCLUSIONS AND IMPLICATIONS These results support the involvement of spinal 5-HT2A receptors in the ability of duloxetine to ameliorate painful diabetic neuropathy. Our data also suggest that the role of 5-HT2A receptors depends on the level of the neuraxis at which activation takes place, with peripheral activation contributing to tactile allodynia in diabetic rats, whereas spinal activation of this receptor alleviates tactile allodynia. The development of selective peripheral 5-HT2A receptor antagonists may offer a novel approach for the treatment of diabetic neuropathic pain.
Influence of alice 3: reducing the hurdles to success in a cs1 programming course

Learning the syntax, semantics, and concepts behind software engineering can be a challenging task for many individuals. This paper examines the Alice 3 software, a three-dimensional visual environment for teaching programming concepts, to determine if it is an effective tool for improving student achievement, raising self-efficacy, and engaging students. This study compares the similarities and differences between a Fundamentals of Programming course with and without Alice integrated into the curriculum. Both the treatment and control Groups are using the same Java materials, assignments, and exams. The treatment group also completes Alice activities for each programming concept throughout the course; as well as two Alice assignments.
A preliminary version of an optical data-flow architecture

The author examines how optical systems can be used to break the bottlenecks that conventional electronic implementation imposes and presents an initial proposal for a high-performance and scalable optical data-flow architecture. The architecture exploits the high degree of connectivity and inherent parallelism in optics for implementing a highly parallel instruction-level data-flow multiprocessing system. Architectural and implementation issues are considered. >
The mechanism of coupling of the locust flight oscillator to oscillatory inputs

1. A flying locust responds to a rhythmically flashing light by adopting a wingbeat frequency equal to the flash frequency, if the flash frequency is not too different from the initial wingbeat frequency (Fig. 2). During this response, the wingbeat cycle maintains a particular timing relative to the light cycle (Fig. 1). 2. This oscillator coupling occurs because each light flash, by exciting the elevator motor neurons and/or the depressor motor neurons, causes an acceleration of the flight cycle by an amount that depends on the timing of the flash relative to the flight cycle (Figs. 4 and 5). The phase of the flight cycle relative to the flashes changes until it reaches a value at which the acceleration in each cycle is just sufficient to result in a flight system frequency equal to the stimulus frequency. The resulting constant phase relationship is stable only if slight fluctuations in the timing of the flight cycle are self-correcting. As predicted theoretically self-correction occurs in that portion of the cycle in which later stimuli result in smaller accelerations of the flight cycle. 3. This mechanism of oscillator coupling has been demonstrated by a similar method of analysis for other biological oscillators (Moore et al., 1963; Enright, 1965). It is shown here how the method of analysis can be extended to certain cases of reciprocally coupled oscillators. 4. Some of the data suggest that there may be only one or two layers of neurons in the central nervous network which generates the motor output pattern in flying locusts.
Decreased total CD19⁺ B lymphocytes and the occurrence of monoclonal proteins are frequent in ultra-long (30 to 44-year) renal transplant recipients: implications for allograft and patient survival.

Abstract Background The B-cell signature of tolerance in kidney transplant patients receiving no immunosuppression includes a significant increase in total CD19 + B cells. Methods We evaluated kidney transplant recipients with primary functioning allografts for 30–44 years receiving minimal immunosuppression to determine whether they have the same CD19 + B-cell changes or unusual serologic findings. We included 44 kidney allograft recipients with a graft functioning for 30–44 years, who were treated primarily with minimal prednisone and azathioprine. Twenty-four other recipients whose allografts functioned >30 years were unable to be studied (unable to travel, lost to follow-up, deceased). Results The number and percentage of CD19 + B cells were depressed in 70.5% (31/44) and 81.8% (36/44), respectively, of these 44 ultra-long renal transplant recipients. The other major finding was identification by immunofixation of a monoclonal protein (MP) in 45.5% (20/44) of these same recipients. Among the 26 patients with good or excellent renal function (estimated glomerular filtration rate [eGFR] ≥ 45 mL/min/1.73 m 2 ; group 1), 12 had a single MP for >1 year, 13 no MP, and 1 a double MP. Conversely, in the 18 patients with fair/failed function (eGFR 2 in 8, or end-stage renal disease after 30 years in 10; group 2), 3 had a transient single MP or free light chains only, 11 no MP, and 4 a double MP ( P = .0425). Conclusions These data reveal that about three quarters of ultra-long renal transplant recipients had low CD19 + B cells, compared with the elevated B-cell signature reported in tolerant kidney recipients, and nearly half (45.5%) had a serum MP that was not associated with low B cells or mortality. Those with a stable single MP had better graft function.
McDonald Observatory Spectral Observations of Comet 19P/Borrelly

Abstract We report on spectroscopic observations of the Deep Space 1 comet target, 19P/Borrelly. These observations were obtained during 1981, 1987, and 1994 at McDonald Observatory. We compute column densities for eight bands at a variety of positions within the coma and use these data and a Haser model in order to derive production rates for the gas. With these production rates, we show that Borrelly is a member of the carbon-chain molecule “depleted” class of comets. We also derive a measure of the dust in the coma ( Af ρ) and show that this is a moderately dusty comet. We see, for the first time, a hint that the ratio C 3 and CH to CN production may vary with heliocentric distance.
THERMAL DUST REVERBERATION IN ACTIVE GALACTIC NUCLEI

An unprecedented and highly successful monitoring campaign was carried out primarily with the UCLA 24inch telescope on a monthly time scale for 51 Seyfert 1 galaxies and quasars. Simultaneous optical and infrared photometry was obtained in order to search for characteristic signatures of thermal dust reverberation. A dozen promising cases of correlated variations were detected, and among them, Markarian 744 was well modeled by reverberation. This theoretical model, fully described and tested here, generates an infrared light curve based on observed optical variations and the assumption that this variability extends into the unobserved ultraviolet which drives the dust to respond. Through varying free parameters, the output infrared light curve is fit to the observed data points. For Mrk 744, a lag time of 32 days and a dust temperature of 1750 K were derived. Two other objects, NGC 6814 and IRAS 03450+0055, were also modeled. NGC 6814 showed a lag time consistent with zero, and the model provides a reasonable fit to the observed data. IRAS 03450+0055 showed a correlation between two events in both light curves, but since this object has less significant variations, the thermal dust model is not as compelling. It is generally accepted that the galaxy Fairall 9 provides a strong case for reverberation, via Barvainis (1992). His methods and results are closely examined here and compared with mine. Contrary to what Barvainis claims, my results indicate that it may be impossible to derive a sensible reverberation model for this object. An untapped resource of untold value is available to the field of AGN variability: amateur astronomers. A world-wide network of observers is already established in the form of the American Association of Variable Star Observers (AAVSO), an organization whose contributions to variable star research are well known. Many of these backyard observers are even now making professional quality observations with CCD cameras. The extension of the AAVSO into variable galactic nucleus observing would be a logical and straightforward undertaking. The benefits of such collective efforts between professional and amateur astronomers are obvious. To highlight the possibilities, a continuing collaboration with one individual is described. One chapter has been published thus far in ApJL 465:L87. It is available online at: www.journals.uchicago.edu/ApJ/joumal/ issues/ApJL7v465n2/521 3/521 3.html. The chapter describing the telescope and cameras has been submitted to the PASP, and other chapters are in preparation for publication.
A note on the quark content of large color groups

Abstract We point out an ambiguity in the generalization of the quark content of SUN color groups for N > 3. We argue that the likely quarks in such groups appear in different representation of the antisymmetrized variety, allowing for a natural three-quark color singlet baryon in the large N expansion.
A review of the linear term in the low temperature specific heat of YBa2Cu3O7−δ

Abstract We have reviewed the low temperature specific heat of high quality single crystal and polycrystalline samples of superconducting YBa 2 Cu 3 O 7−δ , in zero and non-zero applied magnetic fields. The data for single crystals are inconclusive. For polycrystalline samples we have found evidence indicating that the linear term is intrinsic with an average value of γ (0) = 4.6±0.69 mJ/mol K 2 .
Efficient estimation of contact probabilities from inter-bead distance distributions in simulated polymer chains

The estimation of contact probabilities (CP) from conformations of simulated bead-chain polymer models is a key step in methods that aim to elucidate the spatial organization of chromatin from analysis of experimentally determined contacts between different genomic loci. Although CPs can be estimated simply by counting contacts between beads in a sample of simulated chain conformations, reliable estimation of small CPs through this approach requires a large number of conformations, which can be computationally expensive to obtain. Here we describe an alternative computational method for estimating relatively small CPs without requiring large samples of chain conformations. In particular, we estimate the CPs from functional approximations to the cumulative distribution function (cdf) of the inter-bead distance for each pair of beads. These cdf approximations are obtained by fitting the extended generalized lambda distribution (EGLD) to inter-bead distances determined from a sample of chain conformations, which are in turn generated by Monte Carlo simulations. We find that CPs estimated from fitted EGLD cdfs are significantly more accurate than CPs estimated using contact counts from samples of limited size, and are more precise with all sample sizes, permitting as much as a tenfold reduction in conformation sample size for chains of 200 beads and samples smaller than 105 conformations. This method of CP estimation thus has potential to accelerate computational efforts to elucidate the spatial organization of chromatin.
Some properties of a partially purified inhibitor of protein synthesis isolated from bovine cornea.

Abstract Bovine cornea extracted with 0.154 M NaCl yielded a protein fraction which (i) inhibited protein synthesis in rabbit reticulocyte lysates, and (ii) reduced the incorporation of formyl-methionine from f[ 35 S]Met-tRNA f into polypeptides. The inhibition was reversed by millimolar concentrations of glucose 6-phosphate or cAMP and partially reversed by the addition of initiation factor eIF-2. Thus, the corneal inhibitor may act by directly interfering with the activity of eIF-2.
The National Cancer Data Base Report on treatment patterns for hepatocellular carcinomas: improved survival of surgically resected patients, 1985-1996.

BACKGROUND The Commission on Cancer data from the National Cancer Data Base (NCDB) has previously reported data evaluating time trends in various cancers, including such elements as stage of disease at diagnosis, treatment, and survival for multiple tumor sites. In this report, data collected from 1985, 1986, 1990, 1991, 1995, and 1996 for primary hepatocellular carcinoma (HCC) tumors are presented. METHODS The data presented in this review were collected from hospital cancer registries from across the U.S. Eight calls for data have yielded a total 6.9 million cases for the years 1985–1996, including 1158 HCC cases in 1985–1986, 3319 cases in 1990–1991, and 5683 cases in 1994–1995 from hospital cancer registries across the U.S. These data represent approximately 4.3%, 11.2%, and 14.8% of the estimated cases of carcinomas of the liver and biliary tract diagnosed in the U.S. in each of the three respective time periods. RESULTS The outcome for patients diagnosed with HCC remains poor, with only 10% of patients with American Joint Committee on Cancer Stage I disease surviving 5 years. Approximately 50% of patients received no therapy for their HCC, even those with early stage disease. Over these three time periods, the use of chemotherapy appears to have decreased. Among patients diagnosed with Stage II and III disease a difference in survival was noted between those treated with surgery only and those treated with chemotherapy only. Women appear to have a limited survival advantage over men. CONCLUSIONS In spite of an overall poor prognosis, subsets of patients with HCC appear to benefit from surgical resection/ablation of their tumor. The decreasing use of chemotherapy and the early reports of newer ablative techniques (e.g., cryotherapy) suggest that other treatment modalities are emerging. These NCDB data provide a baseline for HCC treatment from which prospective studies are being developed to assess the newer treatments as well as the underlying causes. Cancer 2000;88:912–20. © 2000 American Cancer Society.
Parametric analysis of the heat evolution during hydration of a cementitious plug in a borehole

Abstract Parametric analysis by the computer program ATHENAN of the hydration of a cementitious plug in the borehole of a test rock, showed that the temperature rise within the plug is most sensitive to the size of the plug and moderately sensitive to the conductivities of the plug and the rock followed by less sensitive to the diffusivities of the plug and the rock and the heat transfer coefficient between the rock and the surrounding air. For a given heat of hydration of a mixture, a critical plug size exists given the environmental conditions.
PAINFUL NERVE INJURY DECREASES SARCO-ENDOPLASMIC RETICULUM CA2+-ATPASE ACTIVITY IN AXOTOMIZED SENSORY NEURONS

Abstract The sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) is a critical pathway by which sensory neurons sequester cytosolic Ca2+ and thereby maintain intracellular Ca2+ homeostasis. We have previously demonstrated decreased intraluminal endoplasmic reticulum Ca2+ concentration in traumatized sensory neurons. Here we examine SERCA function in dissociated sensory neurons using Fura-2 fluorometry. Blocking SERCA with thapsigargin (1 μM) increased resting [Ca2+]c and prolonged recovery (τ) from transients induced by neuronal activation (elevated bath K+), demonstrating SERCA contributes to control of resting [Ca2+]c and recovery from transient [Ca2+]c elevation. To evaluate SERCA in isolation, plasma membrane Ca2+ ATPase was blocked with pH 8.8 bath solution and mitochondrial buffering was avoided by keeping transients small (⩽400 nM). Neurons axotomized by spinal nerve ligation (SNL) showed a slowed rate of transient recovery compared to control neurons, representing diminished SERCA function, whereas neighboring non-axotomized neurons from SNL animals were unaffected. Injury did not affect SERCA function in large neurons. Repeated depolarization prolonged transient recovery, showing that neuronal activation inhibits SERCA function. These findings suggest that injury-induced loss of SERCA function in small sensory neurons may contribute to the generation of pain following peripheral nerve injury.
Stability and persistent disturbance attenuation properties for a class of networked control systems: switched system approach

In this paper, both the asymptotic stability and l ∞ persistent disturbance attenuation issues are investigated for a class of networked control systems (NCSs) under bounded uncertain access delay and packet dropout effects. The basic idea is to formulate such NCSs as discrete-time switched systems with arbitrary switching. Then the NCSs' stability and performance problems can be reduced to the corresponding problems of such switched systems. The asymptotic stability problem is considered first, and a necessary and sufficient condition is derived for the NCSs' asymptotic stability based on robust stability techniques. Secondly, the NCSs' l ∞ persistent disturbance attenuation properties are studied and an algorithm is introduced to calculate the l ∞ induced gain of the NCSs. The decidability issue of the algorithm is also discussed. A network controlled integrator system is used throughout the paper for illustration.
Sister chromatid exchanges in isolabeling.

Isolabeling observed by autoradiography in sister chromatids at the second or later metaphases after incorporation of 3H-thymidine has sometimes been ascribed to an exchange between the multiple DNA duplexes in polynemic sister chromatids. An analysis reported here on the frequency and size of isolabeled regions in chromosomes of the rat kangaroo shows that all isolabeling can be accounted for by sister chromatid exchanges coupled with the image spread that can occur in tritium autoradiographs. Hence, in this case it becomes unnecessary to postulate binemy or polynemy to explain isolabeling.
Bank control of the wage fund in Poland: 1950–70

TRADITIONALLY, the socialist firm has been subject to a wage fund plan, although violation of this plan has been of varying practical importance. In the conventional view the socialist firm is under intense pressure to secure enough inputs, including labour, for easy fulfilment of the crucial output plan.1 In this environment the consequences of a shortfall in wages in terms of output plan fulfilment, worker discontent, and ultimately managers' careeis could be crucial. But, if wages are important to the firm, they are also important to the organization primarily responsible for wage control: the central bank which, because of its financial vantage point and general mandate to enforce khozraschet, has been assigned the task of enforcing and, if justified by 'externalities', revising firms' wage plans. Thus it is not surprising that banks and firms are often at loggerheads over wage matters. How is this conflict resolved? This article examines the nature of bank wage control in Poland from 1950 to I970.2
Arrangement of nucleotide sequences in adeno-associated virus DNA

Abstract There are two types of adeno-associated virus virions which contain complementary single-stranded DNA genomes of about 1.4 × 106 daltons. The purified complementary single polynucleotide chains anneal to form duplex linear monomers, circular monomers, and linear dimers, in addition to other less well-defined structures, as identified by sedimentation and electron microscopy. All duplex species are formed by linear single polynucleotide chains of unit length, thus duplex circles and linear dimers are assumed to be held together by relatively short overlapping hydrogen-bonded regions. The initial linear monomers present after annealing the complementary single strands do not form duplex circles or oligomers when re-exposed to annealing conditions, but DNA which sediments as linear monomers after heating linear dimers at a temperature from 7 to 25 deg. C below the Tm of duplex AAV † DNA does re-form oligomers and circles when exposed to annealing conditions. Denaturation and reannealing of any duplex species leads to the formation of all forms, indicating that the over-all single strand composition of all species is equivalent. Disruption of duplex circles by limited exonucleolytic digestion using either 3′ or 5′ exonucleases leads to the conclusion that the overlap region may have either 3′ or 5′ termini and that the overlap region represents less than 6% of the length of the genome. Exonucleolytic digestion of linear monomers to the extent of 50% leaves polynucleotide chains which cannot reanneal after denaturation, thus AAV DNA is not randomly circularly permuted. Duplex linear monomers which do not form circles when exposed to annealing conditions do form duplex circles after 1% exonuclease III digestion. A model consistent with these data is one in which the linear single polynucleotide chains present in AAV virions consist of two or more permutations. All of these chains contain terminal repetitions and their start points occur within a limited region, representing
Simultaneous tracheobronchial and esophageal obstruction caused by a descending thoracic aneurysm

Abstract Descending thoracic aortic aneurysms are a rare cause of symptomatic airway or esophageal obstruction. We report the case of a patient with simultaneous severe dyspnea and dysphagia from the thoracic portion of a thoracoabdominal aortic aneurysm. Perioperative management of the airway obstruction was an essential component of successful treatment. Repair of the aneurysm resulted in resolution of the patient's symptoms. (J VASC SURG 1993;18:90-4.)
Heterocycles and reactive intermediates in the undergraduate organic lab

The nitrile oxide cycloaddition with enamines is useful in illustrating the concepts of reactive intermediates in synthesis and frontier molecular orbital theory.
Surgical approaches: postoperative care and complications "transoral-transpalatopharyngeal approach to the craniocervical junction".

The ventral approach to the craniocervical border has been described for decompression of irreducible extradural pathology. The procedures utilized encompass the transoropharyngeal and median mandibulotomy with glossotomy and the transpalatal procedures. This study was aimed to review the utility of the transoral–transpalatopharyngeal approach. Seven hundred thirty-three patients underwent transpalatopharyngeal approach for decompression of the brain stem and cervicomedullary junction. Of these, 280 were children below the age of 16 years. The main indication was irreducible ventral pathology compressing the brain stem and cervicomedullary junction. Two hundred two children had irreducible basilar invagination, 28 had proatlas segmentation abnormalities, os odontoideum with a dystopic os odontoideum in 30, and spinal tumors in seven (chordoma, fibrous dysplasia, osteoblastoma). Seven patients with Down’s syndrome and irreducible bony compression of the ventral cervicomedullary junction were seen. There were six other miscellaneous diagnoses. All children required craniocervical stabilization which was carried out under the same anesthetic as the transoral procedure. The procedure entailed fiber-optic intubation. The patient was placed in cervical traction prior to the anterior procedure. The soft palate was split only in individuals with a short clivus with a high riding clivus-odontoid articulation. Craniocervical stabilization was performed in the prone position under the same anesthetic. There was one retropharyngeal infection postoperatively. No cesium fluoride leaks were encountered. Velopalatine incompetence was seen in five children who already had preoperative brain stem dysfunction. Neurological recovery was the rule. Patients who had preoperative syringohydromyelia had resolution of the syrinx on postoperative magnetic resonance imaging. The author’s technique is described. Since 1977, the procedure has been performed in 732 patients (280 children) and has evolved into a safe and direct approach to the ventral cervicomedullary junction with minimal morbidity and mortality.