cssi/SciSciGPT-SciSciNet huggingface dataset:
Structural and electronic anisotropy in polycrystalline compactions of the high-Tc superconductor EuBa2Cu3O7−δ

Abstract X-ray diffraction studies show that simple cold-pressing of EuBa2Cu3O7−δ polycrystalline compactions, as practiced by numerous researchers, leads to very large microstructural anisotropy, with the crystallographic c axis preferentially oriented parallel to the axis of pressing. As shown by variable-temperature resistivity and thermoelectric power measurements, the direction of greatest metallic character at temperatures above the superconducting transition temperature is that perpendicular to the pressing direction, i.e., that parallel to the direction in which the (CuO)n sheets and chains are preferentially oriented. Both ϱ(T) and S(T) are only weakly temperature-dependent, with the transition to the superconducting state taking place in both measurements over a slightly narrower temperature range in the perpendicular direction. Above Tc, the S(T) data are positive and give no obvious evidence for phonon-drag or precursor phenomena. A tentative analysis using a Hubbard/Heikes approach yields an average copper oxidation state in good agreement with experiment.
3D current source density imaging based on the acoustoelectric effect: a simulation study using unipolar pulses

It is of importance to image electrical activity and properties of biological tissues. Recently hybrid imaging modality combing ultrasound scanning and source imaging through the acoustoelectric (AE) effect has generated considerable interest. Such modality has the potential to provide high spatial resolution current density imaging by utilizing the pressure-induced AE resistivity change confined at the ultrasound focus. In this study, we investigate a novel three-dimensional (3D) ultrasound current source density imaging approach using unipolar ultrasound pulses. Utilizing specially designed unipolar ultrasound pulses and by combining AE signals associated to the local resistivity changes at the focusing point, we are able to reconstruct the 3D current density distribution with the boundary voltage measurements obtained while performing a 3D ultrasound scan. We have shown in computer simulation that using the present method it is feasible to image with high spatial resolution an arbitrary 3D current density distribution in an inhomogeneous conductive media.
Reference Intervals in Avian and Exotic Hematology

Historically, reference intervals (RI) have come from many sources and been generated by several methods and sample sizes. As RI generation has matured in human laboratory medicine, important guidelines have been adopted in veterinary medicine. Although meeting the goals of these guidelines may be difficult, especially with avian and exotic species, sets of 20 to 40 samples can be used with proper statistical calculations, and other viable alternatives have been examined. The adoption and knowledge of these different methods are important to make a positive move forward in RI generation for special species.
Hypotrichomonas acosta (Moskowitz) from Reptiles. 11. Physiology.

SYNOPSIS. Three strains of Hypotrichomonas acosta were isolated in axenic culture. Attempts to develop a defined medium directly from a defined medium suitable for Tetrahymena pyriformis were unsuccessful. Development of partly defined media by substitution for undefined materials in Diamond's medium were more successful. Horse serum was replaced by 1 mg. % TEM-4T (a diacetyl tartaric acid ester of monoglycerides from tallow) and 0.5 mg.% cholesterol. Yeast extract was replaced by a mixture of ribonucleotides. Inclusion of several additional components permitted reducing the Trypticase concentration from 2% to 0.25%.
Incidence and effect of acute kidney injury after transcatheter aortic valve replacement using the new valve academic research consortium criteria.

Acute kidney injury (AKI) is associated with a poor prognosis after transcatheter aortic valve replacement (TAVR). A paucity of data exists regarding the incidence and effect of AKI after TAVR using the new recommended Valve Academic Research Consortium criteria. At Columbia University Medical Center, 218 TAVR procedures (64.2% transfemoral, 35.8% transapical) were performed from 2008 to July 2011. The creatinine level was evaluated daily until discharge. Using the Valve Academic Research Consortium definitions, the 30-day and 1-year outcomes were compared between patients with significant AKI (AKI stage 2 or 3) and those without significant AKI (AKI stage 0 or 1). Significant AKI occurred in 18 patients (8.3%). Of these 18 patients, 10 (55.6%) had AKI stage 3 and 9 (50%) required dialysis. AKI was associated with a lower baseline mean transvalvular gradient (37.6 ± 11.4 vs 45.6 ± 14.8 mm Hg for no AKI, p = 0.03). After TAVR, the AKI group had a greater hemoglobin decrease (3.6 ± 2.0 vs 2.4 ± 1.3 g/dl, p = 0.01), greater white blood cell elevation at 72 hours (21.09 ± 12.99 vs 13.18 ± 4.82 × 10 3 /μl, p = 0.001), a more severe platelet decrease (118 ± 40 vs 75 ± 43 × 10 3 /μl, p
Futuring, Strategic Planning and Shared Awareness: An Ohio University Libraries' Case Study

ABSTRACT A critical component of strategic planning is creating a shared-awareness among library staff of the potential societal, political, economic and technological changes that will influence how future users will create and consume scholarly materials, what will be expected of library services, and how facilities will be used. The ACRL Futuring scenarios were adapted at the beginning of the Ohio University Libraries strategic planning process to identify such themes and concerns. Those scenarios prompted a series of in-depth and interactive group discussions, which created a shared awareness of possible library futures and guided Ohio University's strategic thinking. Those interactive exercises led by Professor David Staley, and the subsequent discussions surrounding the scenarios, represent a best practice for other librarians and staff who are attempting to understand the external factors that shape society, higher education and the future of libraries.
Total elbow arthroplasty after resection of tumors at the elbow.

Between 1980 and 1993, 13 patients underwent total elbow arthroplasty at the authors' institution after resection of tumors around the elbow. Arc of elbow motion from extension to flexion improved from a preoperative mean of 29° to a postoperative mean of 73°. Pain scores decreased from a preoperative mean of 3.6 to a postoperative mean of 2.0. Three patients had an excellent, six had a good, two had a fair, and two had a poor result. All seven patients with primary tumors had good or excellent results, compared with only two of six patients with metastatic lesions to the elbow. The data from this study suggest total elbow arthroplasty after resection of tumors provides significant pain relief and improvement in function. Patients with metastatic lesions may be candidates for the procedure, especially if all other methods of palliation have been exhausted. However, the results for patients with metastatic lesions may not be satisfactory.
Sigmoid-urachal-cutaneous fistula in an adult male.

An infected urachal cyst is an uncommon finding in adults. We report the first case of a sigmoid–urachal–cutaneous fistula that resulted from rupture of an infected urachal cyst in an adult male. Definitive management consisted of resection of the urachus with a bladder cuff, along with removal of the affected bowel segments and bowel anastomosis.
Report on the BooksOnline'10: third workshop on research advances in large digital book repositories and complementary media

The BooksOnline Workshop series aims to foster the discussion and exchange of research ideas and initiatives addressing challenges and exploring opportunities around large collections of digital books and complementary media. The third workshop in the series, BooksOnline' 10 boosted a high quality program, including keynote addresses by James Crawford from Google Books and John Mark Ockerbloom from the University of Pennsylvania. From the accepted papers two main themes emerged: 1) Issues relating to building suitable infrastructure for online book collections and for the evaluation of the applications and services that make use of such collections, and 2) Opportunities relating to the social or collaborative reading and annotation of books and issues relating to the design of suitable eReaders. This paper provides a summary of the workshop and the accepted contributions.
Abnormal nuclear states and vacuum excitation

The structure of the vacuum is examined assuming the existence of a strongly interacting neutral spin-0 even-parity meson or resonance. Abnormal nuclear states, the sigma model, and pure vacuum excitation are considered. (JFP)
Development of integrated materials database system for plant facilities maintenance & optimization

Features of the materials database system for plant facilities management are discussed here. Korea Electric Power Research Institute (KEPRI) has developed web-based materials database system for power plant engineers with an aim to give them the integrated materials information which is needed in solving material-related problems frequently occurred in plant maintenance activities. The materials database system contains more than twenty thousands material standard data of eight countries including chemical composition, mechanical properties, and their applications in the power plant facilities. Using the system, users can find useful information of equivalent material standards and physical or chemical environments where the material is applied. Integration of material data with facility data is expected to give more valuable information to plant engineers in solving their material related problems. The database system also adopted state-of-arts extensible markup language (XML) technology and was designed to share its data easily with other information systems such as plant engineering expert system, materials management system, enterprise resource planning (ERP) system and so on.
Effect of Single-Strand Break on Holliday Junction Migration Dynamics: A Single-Molecule Fluorescence Study

Single-strand breaks (SSBs) are the most common DNA lesions in living cells. SSBs occur three orders of magnitude more frequently than double-strand breaks. Unrepaired SSBs lead to blockage or collapse of DNA replication forks, possibly causing formation of double-strand breaks. Holliday junctions (HJ) play central role in various DNA functions including repair of lesions, replication, homologous and site-specific recombination. Branch migration, either spontaneous or protein-mediated, is among widely employed mechanisms in these functions. Therefore, elucidation of the SSB effect on spontaneous branch migration of HJs is a problem of great importance. To accomplish this task, we employed single-molecule FRET approach developed before, allowing us to follow spontaneous branch migration of one HJ at a single base pair level in real time. One SSB was incorporated in the middle of the homologous region of mobile HJ with the donor and acceptor dyes placed on its opposite arms. The data showed that branch migration does not stop at these lesions or reflects from them. Our previous results showed that branch migration is a step-wise process and one step can cover entire homology region. The analysis of the time trajectories showed that such long steps are not prevented by SSBs. Step size distributions for HJs containing SSB were obtained and such characteristics of these distributions as the mean hop size and the distributions width remain virtually the same as in the designs without a break. Lifetimes of folded states were found to be very similar to that in control, just slightly increasing around the SSB in the AT-rich design. We also studied an immobile HJ with a SSB at the junction. Its arms remain in antiparallel orientation, very similarly to our previous studies.Supported by the NSF grant PHY-0615590 (YLL).
Serial organization of motor skills in left- and right-handed adults

Abstract Normal right- and left-handed men and women were examined for their ability to tap in time to a metronome with the fingers of the left and right hands, and to tap simple rhythmic patterns repeatedly. The two handedness groups showed no manual asymmetry on the metronome entraining trials, but both tapped the rhythmic patterns with greater precision with the right hand than the left. Right-handed females tapped more precisely than other groups with the left hand but not with the right. The left hemisphere appears to be relatively specialized for the serial organization of fine motor movements in both left- and right-handers.
Geothermal energy from hot dry rock: A renew able energy technology moving towards practical implementation

Abstract The technology to extract useful amounts of energy from the large, ubiquitous, hot dry rock (HDR) resource has been under development for more than twenty years. Initial work during the 1970's and 1980's showed that it is possible to access and extract HDR energy using techniques originally conceived and tested by the Los Alamos National Laboratory. The process entails drilling a well deep enough to reach hot rock, injecting water at high enough pressure to open natural joints in the rock, and returning the water, heated by the rock, to the surface through one or more additional wellbores. After extraction of its thermal energy, the water is recirculated through the hot rock to mine more heat. In this closed-loop process, nothing is released to the environment except heat, and no long-term wastes accumulate. The practical potential of HDR technology was demonstrated in a series of flow tests conducted from 1992 to 1995 at the HDR pilot facility at Fenton Hill, NM. These tests showed that energy can be extracted from HDR in significant amounts over extended time periods. Extensive analyses and reservoir characterization studies carried out as part of the testing program provided a large amount of information about the dynamics of the heat extraction process and confirmed that HDR energy production facilities can be operated with minimal environmental effects. Operating strategies evaluated during the test period included the production of energy at steady-state levels for extended periods and on a variable-output schedule particularly suited to load-following electricity generation.
A convenient linearization of high-pressure x-ray diffraction data

Abstract Compression curves of crystalline materials subjected to high pressures at normal temperatures can be linearized by the expression [ P η ] 1 2 = B 1 2 0 + s [Pη] 1 2 ] , where P = pressure, η = 1 − V V 0 , V = volu e at P, V0 = initial volume, B0 = isothermal bulk modulus, and s = (B' 0 + 1) 4 , B'0 being the pressure derivative of B0 as P goes to zero.
A calibration system for evaluating the performance of harmonic power analyzers

The paper describes a calibration system which is being used to evaluate the performance of harmonic power analyzers and related equipment. A method for verifying the software based calculations of the harmonic quantities obtained with the digital recorder of the calibration system is discussed. Test results of a harmonic power analyzer are also included. >
THERMAL CONDUCTIVITY OF HIGH-PURITY THORIUM.

The thermal conductivity and the electrical resistivity of three high-purity thorium samples with resistivity ratios 31, 140, and 480 have been measured as functions of temperature from 3 to 300 K. The samples were purified by the electrotransport method. Each of our higher-purity samples showed a large thermal conductivity maximum near 10 K and a constant thermal conductivity from 70 to 200 K. At low temperatures, the Lorenz ratios of samples having intermediate purity show, in addition to the linear term arising from electronic thermal conductivity, a quadratic term arising from phonon thermal conductivity limited by phonon-electron scattering. At higher temperatures, the phonon thermal conductivities of these samples vary inversely as the temperature owing to the dominance of unklapp phonon-phonon scattering. The ideal electronic thermal resistivity from 14 to 25 K was proportional to the square of the temperature as expected for electron-phonon scattering.
Autodetaching States of Cl

A number of peaks appear in the spectrum of electrons produced by collisions of ${\mathrm{Cl}}^{\ensuremath{-}}$ ions with helium- and hydrogen-gas targets. These features can be attributed to doubly excited autodetaching states of ${\mathrm{Cl}}^{\ensuremath{-}}$. Assignment of approximate electron configurations is possible for states appearing at 8.53, 9.15, and 9.97 eV, but ambiguities remain in the assignments for the other states lying between 10.47 and 12.44 eV.
Fermi surface of Bi(111) measured by photoemission spectroscopy.

Synchrotron radiation angle-resolved photoemission spectroscopy of Bi(111) shows that the Fermi surface consists of six elongated hole pockets along the $\overline{\ensuremath{\Gamma}M}$ directions surrounding a ring-shaped electron pocket centered at $\overline{\ensuremath{\Gamma}}$, all of which have two-dimensional character. The associated hole and electron sheet densities are ${p}_{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.1\ifmmode\times\else\texttimes\fi{}{10}^{13}{\mathrm{cm}}^{\ensuremath{-}2}$ and ${n}_{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}5.5\ifmmode\times\else\texttimes\fi{}{10}^{12}{\mathrm{cm}}^{\ensuremath{-}2}$, respectively. A weak emission feature associated with the bulk hole pocket in the Fermi surface was identified. The Fermi momentum of the bulk hole band near the $T$ point is ${k}_{F}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.013\ifmmode\pm\else\textpm\fi{}0.003{\AA{}}^{\ensuremath{-}1}$.
Regulation of the Porcine 1,25-Dihydroxyvitamin D3-24-Hydroxylase (CYP24) by 1,25-Dihydroxyvitamin D3 and Parathyroid Hormone in AOK-B50 Cells

The 24-hydroxylase is the enzyme responsible for the first step in the catabolism of 1,25-dihydroxyvitamin D3, the active form of vitamin D. This enzyme was shown to be upregulated by 1,25-dihydroxyvitamin D3 itself and downregulated by parathyroid hormone (PTH). Upregulation of 24-hydroxylase by 1,25-dihydroxyvitamin D3 has been characterized; however, the mechanism by which PTH acts to downregulate 24-hydroxylase expression remains unknown. Here we report the cloning of the porcine 24-hydroxylase, and show that 1,25-dihydroxyvitamin D3-stimulated 24-hydroxylase mRNA and activity are repressed by PTH in AOK-B50 cells, a porcine kidney proximal tubule cell line with stably transfected opossum PTH receptors. Forskolin mimicked the effects of PTH consistent with in vivo data, and suppression by PTH was not due to changes in VDR levels. The first 1400 bp of the 24-hydroxylase promoter were not able to mediate the effects of PTH on a reporter gene. In view of the above findings we concluded that AOK-B50 cells are a suitable model for further studying the mechanism of action of PTH on 24-hydroxylase mRNA.
Selective cortical representation of attended speaker in multi-talker speech perception

The neural correlates of how attended speech is internally represented are described, shedding light on the ‘cocktail party problem’. The 'cocktail-party problem' — the question of what goes on in our brains when we listen selectively for one person's voice while ignoring many others — has puzzled researchers from various disciplines for years. Using electrophysiological recordings from neurosurgery patients listening to two speakers simultaneously, Nima Mesgarani and Edward Chang determine the neural correlates associated with the internal representation of attended speech. They find that the neural responses in the auditory cortex represent the attended voice robustly, almost as if the second voice were not there. With these patterns established, a simple algorithm trained on various speakers predicts which stimulus a subject is attending to, on the basis of the patterns emerging in the secondary auditory cortex. These results suggest that speech representation in the brain reflects not only the acoustic environment, but also the listener's understanding of these signals. As well as shedding light on a long-standing neurobiological problem, this work may give clues as to how automatic speech recognition might be improved to cope with more than one talker. Humans possess a remarkable ability to attend to a single speaker’s voice in a multi-talker background1,2,3. How the auditory system manages to extract intelligible speech under such acoustically complex and adverse listening conditions is not known, and, indeed, it is not clear how attended speech is internally represented4,5. Here, using multi-electrode surface recordings from the cortex of subjects engaged in a listening task with two simultaneous speakers, we demonstrate that population responses in non-primary human auditory cortex encode critical features of attended speech: speech spectrograms reconstructed based on cortical responses to the mixture of speakers reveal the salient spectral and temporal features of the attended speaker, as if subjects were listening to that speaker alone. A simple classifier trained solely on examples of single speakers can decode both attended words and speaker identity. We find that task performance is well predicted by a rapid increase in attention-modulated neural selectivity across both single-electrode and population-level cortical responses. These findings demonstrate that the cortical representation of speech does not merely reflect the external acoustic environment, but instead gives rise to the perceptual aspects relevant for the listener’s intended goal.
The concentration and binding of thyroxine in the serum of patients with the testicular feminization syndrome: observations on the effects of ethinyl estradiol and norethandrolone.

In 6 castrated patients with the complete testicular feminization syndrome, values for total and free thyroxine (T4) concentration in serum, as well as the T4-binding capacities of thyroxine binding globulin (TBG) and thyroxine binding prealbumin (TBPA), were within normal limits. As expected, patients with TFS responded to 0.02 mg ethinyl estradiol daily with increases in both the T4-binding capacity of TBG and the concentration of serum T4 and a decrease in the proportion of free T4. The magnitude of the responses was similar to that obtained in 3 normal patients given the same dose of ethinyl estradiol. In a normal patient receiving ethinyl estradiol, norethandrolone (40 mg daily) produced the expected decrease in TBG and total T4 concentration and increase in the percentage of free T4. In contrast, in 4 patients with TFS receiving ethinyl estradiol, norethandrolone did not influence TBG, total serum T4 concentration, or the proportion of free T4. A similar lack of effect of norethandrolone on TBG was ...
p66shc Inhibits Insulin-like Growth Factor-I Signaling via Direct Binding to Src through Its Polyproline and Src Homology 2 Domains, Resulting in Impairment of Src Kinase Activation

p66shc is increased in response to cell stress, and these increases regulate growth factor actions. These studies were conducted to determine how p66shc alters IGF-I-stimulated Src activation, leading to decreased IGF-I actions. Our results show that p66shc binds to Src through a polyproline sequence motif contained in the CH2 domain, a unique domain in p66shc, and IGF-I stimulates this interaction. Disruption of this interaction using a synthetic peptide containing the p66shc polyproline domain or expression of a p66shc mutant containing substitutions for the proline residues (P47A/P48A/P50A) resulted in enhanced Src kinase activity, p52shc phosphorylation, MAPK activation, and cell proliferation in response to IGF-I. To determine the mechanism of inhibition, the full-length CH2 domain and intact p66shc were tested for their ability to directly inhibit Src kinase activation in vitro. The CH2 domain peptide was clearly inhibitory, but full-length p66shc had a greater effect. Deletion of the C-terminal Src homology 2 domain in p66shc reduced its ability to inhibit Src kinase activation. These findings demonstrate that p66shc utilizes a novel mechanism for modulating Src kinase activation and that this interaction is mediated through both its collagen homologous region 2 and Src homology 2 domains.
De Novo Ligand Design: Understanding Stereoselective Olefin Binding to [(η5-C5H5)Re(NO)(PPh3)]+ with Molecular Mechanics, Semiempirical Quantum Mechanics, and Density Functional Theory

Understanding stereoselective prochiral α-olefin binding by a chiral organometallic moiety is essential to control the production of a desired stereoisomer. Computational methods are useful predictors of stereoisomers, ifall conformations that can participate in a reaction are identified. Herein we report a combined molecular mechanics, semiempirical quantum mechanics, and density functional theory study of binding of CH 2 =CHR, R = Me, n-Pr, CH 2 Ph, Ph, i-Pr, t-Bu, SiMe 3 , to chiral [(η 5 -C 5 H 5 )Re(NO)(PPh 3 )] + . In agreement with the experimental literature and previous computational results, one isomer was predicted to form preferentially over others. Brown's ligand repulsive energy was used to quantify the steric demand of the α-olefin in the organorhenium environment. A new conformational searching method, which requires successive applications of molecular mechanics, semiempirical quantum mechanics, density functional theory, restricted molecular mechanics, and density functional theory is introduced in order to identify all conformational minima that can participate in a reaction. A computationally derived diastereoselective excess based on DFT computations is derived and compared with experiment.
A shellable poset that is not lexicographically shellable

It is known that a lexicographically shellable poset is shellable, and it has been asked whether the two concepts are equivalent. We provide a counterexample, a shellable graded poset that is not lexicographically shellable.
OCCURENCE OF ARTHRITIS FOLLOWING ERYTHEMA INFECTIOSUM(EI) IN HLA-B27+ MEMBERS OF A FAMILY

We have identified a family in which typical EI developed in an epidemic setting in four male siblings and their father. Three individuals who were HLA-B27+ developed arthritis (Figure). Two nine year old twins developed joint pains and morning stiffness five days after the onset of rash and fever, and one of these has continued to have small joint arthritfs of his hands and feet. Their father also became febrile and subsequently developed low back pain and joint stiffness. The ANA and RF were negative. Two other children with EI who Were HLA-B27- had no arthritis. Human parvovirus has been shown to be the likely etiologic agent of EI. Our observations suggest that one form of arthropathy in EI has features in common with reactive arthritis, and occurs in genetically susceptible individuls
Autosomal dominant retinitis pigmentosa caused by the threonine-17-methionine rhodopsin mutation: retinal histopathology and immunocytochemistry.

Abstract The retinas from a 68-year-old man with autosomal dominant retinitis pigmentosa caused by the threonine-17-methionine rhodopsin mutation were studied. Patients with this mutation have a characteristic clinical phenotype that shows intra- and interfamilial consistency. The retinas were examined by light and electron microscopy, including immunocytochemistry with markers for rods, cones, the retinal pigment epithelium, the interphotoreceptor matrix and Muller cells, and the results were correlated with those from visual function tests performed fourteen months before death. Grossly, both retinas had heavy deposits of bone spicule-like pigmentation inferiorly, but the superior retinas showed much less pigmentation. The maculas contained no rods and an incomplete monolayer of cone somata, consistent with the patient's severely reduced central vision. The inferior retinas contained no rods and rare cone somata, correlating with an absolute scotoma in the superior held. The superior retinas had near-normal-appearing rods and cones in the far periphery and a gradient from the midperipheral to central retina of progressively shortened outer segments and loss of photoreceptors, consistent with the patient's reduced rod and cone electroretinograms and retained rod and cone sensitivities in the inferior peripheral held by perimetry. Immunocytochemistry with rod-specific markers was qualitatively normal in the superior mid to far peripheral retina. Electron microscopic immunogold labeling with anti-rhodopsin revealed similar densities of gold particles over rod outer segments of the RP and a normal donor retina. Degenerate photoreceptors in the superior equatorial region of the RP retina had short outer segments, and some rods had surface labeling with anti-rhodopsin of the inner segments, somata and synapses. The results indicate regional retinal differences of disease severity in this genotype and that rods in the superior peripheral retina have normal morphology despite the presence of the mutant allele. To the authors' knowledge, this is the first detailed study of rod photoreceptors in the retina of an RP patient with a rhodopsin mutation.
Muller glia, vision-guided ocular growth, retinal stem cells, and a little serendipity: the Cogan lecture.

Hypothesis-driven science is expected to result in a continuum of studies and findings along a discrete path. By comparison, serendipity can lead to new directions that branch into different paths. Herein, I describe a diverse series of findings that were motivated by hypotheses, but driven by serendipity. I summarize how investigations into vision-guided ocular growth in the chick eye led to the identification of glucagonergic amacrine cells as key regulators of ocular elongation. Studies designed to assess the impact of the ablation of different types of neurons on vision-guided ocular growth led to the finding of numerous proliferating cells within damaged retinas. These proliferating cells were Muller glia–derived retinal progenitors with a capacity to produce new neurons. Studies designed to investigate Muller glia–derived progenitors led to the identification of a domain of neural stem cells that form a circumferential marginal zone (CMZ) that lines the periphery of the retina. Accelerated ocular growth, caused by visual deprivation, stimulated the proliferation of CMZ progenitors. We formulated a hypothesis that growth-regulating glucagonergic cells may regulate both overall eye size (scleral growth) and the growth of the retina (proliferation of CMZ cells). Subsequent studies identified unusual types of glucagonergic neurons with terminals that ramify within the CMZ; these cells use visual cues to control equatorial ocular growth and the proliferation of CMZ cells. Finally, while studying the signaling pathways that stimulate CMZ and Muller glia–derived progenitors, serendipity led to the discovery of a novel type of glial cell that is scattered across the inner retinal layers.
Multiyear increases in dissolved organic matter inventories at Station ALOHA in the North Pacific Subtropical Gyre

The inventories and dynamics of dissolved organic matter (DOM) in the surface water at Station ALOHA were analyzed from the Hawaii Ocean Time-series (HOT) data set for the period 1989‐1999. Euphotic zone, depthintegrated (0‐175 m) concentrations of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) were temporally variable. In particular, during the period 1993‐1999, concentrations of DOC and DON increased while inventories of DOP remained unchanged. DOC inventories increased by 303 mmol C m 22 yr 21 , a value equivalent to approximately 2% of measured primary production ( 14 C method) at this site. DON increased at 11 mmol N m 22 yr 21 , resulting in a mean molar DOC : DON ratio of 27.5 for the accumulated DOM. Accumulation of DOC and DON without corresponding accumulation of DOP resulted in changes to the bulk organic C : N : P stoichiometry; bulk DOC : DOP ratios increased 16% and DON : DOP ratios increased by 17%. These results indicate that a small fraction of the annually produced organic matter escaped biological utilization on time scales of months to years. More importantly, the accumulated DOM inventories grew progressively enriched in C and N relative to P. Fundamental changes in the North Pacific Subtropical Gyre (NPSG) habitat appear to have altered microbial processes that regulate organic matter fluxes. Considered together, the long-term increases in DOC and DON inventories are consistent with previous observations, indicating that a recent reorganization of plankton community dynamics may have altered organic matter cycling in this ecosystem.
Silicon Strength Testing for Mesoscale Structural Applications

The development of power MEMS, such as the Microengine being developed at MIT, requires highly stressed structures to achieve high power densities. Material strength is, therefore, a critical issue for the design of such devices. Due to the stochastic nature of the strength of brittle materials, the length scales of the test specimens should be close to those of the structure in order to avoid excessive extrapolation of the test data. In this paper, strength characterization and supporting analysis of mesoscale biaxial flexure and radiused hub flexure single crystal silicon specimens are presented. The Weibull reference strength’ of planar biaxial flexure specimens was found to lie in the range 1.2 to 4.6 GPa, depending on the surface quality. The local strength at stress concentrations was obtained by testing radiused hub flexure specimens. For the case of deep reactive ion etched (DRIE) specimens, the strength at fillet radii was found to be significantly lower than that measured from planar biaxial flexure specimens due to the inferior surface quality in such regions. It was found that strength could be significantly increased by the introduction of an additional isotropic etch after the DRIE step. The test results reported herein have important implications for the development of highly stressed microfabricated structures. The sensitivity of the mechanical strength to surface processing and etching techniques must be accounted for in the design cycle, particular with regard to the selection of the appropriate fabrication route. Furthermore, in the design of highly stressed MEMS devices, it is important to account for the stochastic nature of the material strength.
The Neonatal Adaptive Immune System

After completing this article, readers should be able to: 1. Describe the basic sequence of events that initiates an immune response. 2. Understand the basic differences between neonatal and adult T-cell function. 3. Describe the accumulation of maternal immunoglobulin G in the fetus. 4. Understand the barriers to strong B-cell function in the neonate. In 1960, the famous immunologist Peter Medawar was awarded a Nobel Prize for experiments describing the relative ease with which fetal immune systems develop tolerance to foreign antigens. (1) Neonates, therefore, were viewed as “immunodeficient,” and the neonatal period was believed to be a unique window in time during which any antigen encountered by the immune system would be tolerated and included in the repertoire of “self” antigens. However, more recent experiments have proven that, under the right conditions, the neonatal immune system generates responses similar in strength and quality to those of adults, leading some to speculate that when it comes to the immune system, there is “nothing special about the neonate.” (2) The truth lies somewhere in the middle of these two extreme views. The success of modern vaccination programs confirms that infants can mount significant immune responses. However, in the face of other immunologic challenges, such as group B streptococcal infections, infants demonstrate obvious weaknesses compared with adults. What do we know about the neonatal immune system? In what ways is it different from the adult immune system? What are the cellular and molecular mechanisms for these differences? This review summarizes the development of T- and B-cell immunity in the human neonate, with emphasis on the clinical implications of data. The adaptive immune system consists of T cells, B cells, and their products. (3) T cells are lymphocytes defined by their surface expression of the T-cell receptor (TCR) and are divided into subsets based on their surface …
Transposition-mediated DNA re-replication in maize

To make accurate copies of its genome, a cell takes precautions to make sure each section of DNA is only duplicated once in every round of copying. However, there are some sections of DNA called transposons that can avoid these restrictions and be duplicated more often. Transposons are mobile pieces of DNA: they can be ‘cut’ from one section of the genome and are able to ‘paste’ back in somewhere else. The amount of mobile DNA in a genome varies a great deal between species, and in the crop plant maize, it makes up nearly 85% of the genome. Some transposons can move while the genome is being duplicated. If a transposon is cut out of a section of DNA that has already been copied and is pasted into a site that is yet to be copied, the transposon can be copied again. The transposon may now be present in two different places in the genome. If two transposons are close together on a section of DNA, both transposons can move at the same time. As they move, they can carry along pieces of the genome, transferring them from one site to another. These transferred pieces can include sections of, or even entire, genes. This is called alternative transposition, but it is not clear whether this process can happen when the genome is actively being duplicated. Here, Zhang et al. studied transposons in maize. The experiments found that alternative transposition can take place between a site that has already been copied and another site that is still waiting to be copied. Therefore, after the round of copying is completed, both transposons and the flanking DNA can be present in two places in the genome. When single transposons move, or alternative transposition takes place, sections of the genome can be rearranged and genes can be deleted or new ones can be created. Therefore, transposons may have contributed to rapid evolution in maize and possibly other species.
Is there a mechanism for introducing acid hydrolases into liver lysosomes that is independent of mannose 6-phosphate recognition? Evidence from I-cell disease

Abstract We have examined frozen liver tissue for N-acetylglucosamine-l-phosphotransferase, an enzyme required for the formation of the mannose 6-phosphate recognition marker of lysosomal enzymes. Using [β32P]-UDPGlcNAc and placental β-hexosaminidase B as N-acetylglucosamine l-phosphate donor and acceptor, respectively, we were unable to find activity of the transferase in 100,000 × g membranes prepared from livers of patients with I-cell disease, whereas activity was readily observed in membranes from control livers stored under the same conditions. Yet the activity of several lysosomal enzymes (β-N-acetylglucosaminidase, β-glucuronidase, α-mannosidase and α- L -iduronidase) was comparable in liver tissue of I-cell patients and controls, and only β-galactosidase activity showed a marked reduction. These results suggest that in contrast to cultured skin fibroblasts, liver may be able to introduce into lysosomes acid hydrolases that lack the mannose 6-phosphate recognition marker.
EFFECT OF LENS-MODEL AND OUTCOME FEEDBACK IN A SOCIAL JUDGMENT ANALOGUE

Summary.-96 Ss judged the correct category designations of human-like figures which differed with respect to four facial cues. The task was designed so that the correct category was defined by a linear function of the cues. Ss were randomly assigned to one of 4 feedback conditions in which they received (1) traditional "right" vs "wrong" feedback after each trial, (2) the correct category of each figure, (3) the values of each cue for each figure, or (4) the linear function relating the cues to the categories. The results were analyzed by Tucker's modification of the Brunswikian lens model equations. Ss who received "lens" feedback gained significantly more knowledge of the task system than Ss in traditional outcome feedback conditions, exercised significantly greater control over that knowledge, and achieved a significantly higher level of accuracy in their judgments. These results are discussed in terms of their relevance for situations of social judgment. One of the most widely accepted conclusions from the rapidly expanding literature on multiple-cue probability learning is that training naive Ss to perform well on tasks involving complex inference is a painstakingly slow, often dismally unrewarding enterprise (cf. Peterson, Hammond, 8: Summers, 1965). Goldberg (1968) recounts, for instance, how judges required several thousand trials with feedback on outcome to improve in discriminating MMPI profiles according to a dichotomous criterion. Nevertheless, feedback in which Ss receive information about the accuracy of their judgments on some ratio or interval schedule of reinforcement, has by far been the most prominent training technique (Dudycha & Naylor, 1966'). Recently, however, Harnmond and his associates (cf. Hammond & Boyle, 1971) have suggested that other forms of feedback may be more instructive to Ss than simply providing an index of accuracy of prediction on a particular trial. These types of feedback are sometimes referred to as "lens" feedback because they are derived from an analysis of clinical judgment which utilizes Brunswik's lens model (cf. Brunswik, 1955). In this context, Summers and Hamrnond (1966) found that some information regarding the nature of the functional relationship among the variables, i.e., linear or nonlinear, was helpful to Ss beyond being shown the correct answer after each trial. In the first study of its kind, Todd and Hammond (1965) compared the efficacy of tlraditional feedback on outcome with feedback which enabled Ss to see the validity of each cue and the form of the relation between
Pricing of the Eurodollar bank rate

The Eurodollar bank rate has been widely viewed as one of the chief barometers of credit market conditions in the Eurocurrency markets, yet not enough is known about how this rate is determined. For example, most of the short-to-medium term loans made by banks in the Eurocurrency market are floating rate loans linked to the London Interbank Offered Rate (LIBOR). The Eurocurrency interbank market “encompasses over 1,000 banks from 50 different countries, with a total market size of $3.3 trillion . . . transactions in U.S. dollars are the most prominent.. [13, p. 171. The objective of this paper is to attempt to further our understanding of the pricing of the Eurodollar bank rate through an analysis of recent Eurodollar bank rate movements. Empirical studies on determination of the Eurodollar bank rate [l, 7,11,12], generally have viewed the Eurodollar market as a major financial intermediary that channels short-term funds among the money markets of industrial countries. In these studies, the dollar-denominated risk-free rate of return (U.S. Treasury bill rate) is taken to be the principal determinant of the Eurodollar bank rate.’ Moreover, these studies anticipate that the maximum adjustment in the Eurodollar bank rate will be on a one-to-one basis to changes in the U.S. Treasury bill rate. Using both quarterly and monthly data for 1957-64, Hendershott estimated a stock-flow adjustment equation of the “Koyck-Nerlove” type. He concluded that, “in response to a one percentage point rise in the mean U.S. bill rate, . . . the eventual increase in the Eurodollar rate will be . . . 1.07 percentage points. This is not significantly greater than the maximum anticipated value of unity” [7, p. 4621. Using a multiple regression approach and monthly data for the period 1961-71, Argy and Hodjera [l] showed that the maximum value of the estimated coefficient on the U.S. Treasury bill rate is 0.62. Mills [12], using a similar approach and weekly data for 1966-70, showed that the maximum value is 0.61. In this paper the basic relationship between the Eurodollar bank rate and a dollar-denominated risk-free rate of return (the U.S. Treasury bill rate) is examined.
The mouse lpA3/Edg7 lysophosphatidic acid receptor gene: genomic structure, chromosomal localization, and expression pattern

Abstract The extracellular signaling molecule, lysophosphatidic acid (LPA), mediates proliferative and morphological effects on cells and has been proposed to be involved in several biological processes including neuronal development, wound healing, and cancer progression. Three mammalian G protein-coupled receptors, encoded by genes designated lp (lysophospholipid) receptor or edg (endothelial differentiation gene), mediate the effects of LPA, activating similar (e.g. Ca 2+ release) as well as distinct (neurite retraction) responses. To understand the evolution and function of LPA receptor genes, we characterized lp A3 / Edg7 in mouse and human and compared the expression pattern with the other two known LPA receptor genes ( lp A1 / Edg2 and lp A2 / Edg4non-mutant ). We found mouse and human lp A3 to have nearly identical three-exon genomic structures, with introns upstream of the coding region for transmembrane domain (TMD) I and within the coding region for TMD VI. This structure is similar to lp A1 and lp A2 , indicating a common ancestral gene with two introns. We localized mouse lp A3 to distal Chromosome 3 near the varitint waddler ( Va ) gene, in a region syntenic with the human lp A3 chromosomal location (1p22.3-31.1). We found highest expression levels of each of the three LPA receptor genes in adult mouse testes, relatively high expression levels of lp A2 and lp A3 in kidney, and moderate expression of lp A2 and lp A3 in lung. All lp A transcripts were expressed during brain development, with lp A1 and lp A2 transcripts expressed during the embryonic neurogenic period, and lp A3 transcript during the early postnatal period. Our results indicate both overlapping as well as distinct functions of lp A1 , lp A2 , and lp A3 .
Growth Instability During Nonuniform Directional Solidification of Pure Metals

Solidification of a pure metal against a flat mold surface is examined using a nonuniform thermohypoelastic beam. Heat is removed with a spatially periodic heat flux superimposed onto uniform cooling, which leads to irregular growth of the casting. The associated nonuniform temperature field also produces nonuniform deformation in the casting which in time may lead to air gap nucleation along the mold/casting interface. Air gap nucleation is defined as the circumstance where the local mold/casting interface pressure falls to zero. Unstable growth occurs when such air gaps nucleate beneath thickness minima, thus further reducing heat transfer at these positions, and dramatically amplifying the existing thickness nonuniformity. The time to onset of instability depends upon material properties such as density, latent heat, thermal conductivity, elastic constants, and coefficient of thermal expansion as well as upon process parameters such as cooling rate, fluid pressure, and wavelength of the periodic heat flux.