cssi/SciSciGPT-SciSciNet huggingface dataset:
Magnetism of Mixed Valence Compounds.

Mixed valence compounds exhibit a wide range of magnetic properties. These properties range from simple diamagnetism which is temperature independent and which may be estimated rather accurately from Pascal’s constants, to Curie-Weiss paramagnetism, to exceptionally complicated behavior which may arise from single ion effects, exchange coupling interactions, or both. Studies of the magnetic properties of mixed valence compounds often yield valuable information concerning the chemical nature and electronic structure of the substances. In this chapter, results ofrepresentative studies of magnetic properties of mixed valence compounds will be described with the aim of illustrating the phenomena which are exhibited and the manner in which the results are used in the solution of chemical problems. Systems of discrete clusters, chains, sheets, and three dimensional polymeric materials will be discussed here. For the most part, these will be compounds in which metal ions are bridged by ligands such as halides,oxide, pyrazine, and other ions and small molecules, although representative results for compounds containing metal-metal bonds will be included. Because of space limitations and a recent review on the subject, results on mixed valence metalloproteins and enzymes will not be covered.
State Attorney General Regulation Of Charitable Hybrid Forms: To Be Or Not To Be Charitable

One of the most significant challenges for state officials responsible for regulating charities in their state is how to approach their duties with regard to the growing trend of hybrid enterprises and business forms. More specifically, there are questions about whether these new forms are more like charitable trusts and should be treated as such, if they are more like profit- oriented tax paying enterprises and should be so treated, or if they are something so new and different that they require some combination of the two or wholly original approaches. Although understandable to want to regulate these forms as if charitable trusts or otherwise subjected to charitable oversight, it is not the only alternative and may not be the best for society. Other tools are available to protect the public and hold managers, officers, directors, and members/owners accountable. In addition, many of the reasons to impose charitable oversight on exempt organizations do not apply to these hybrid forms. Such oversight is not consistent with historical approaches to charitable activities pursued by non-hybrid, non-exempt forms. A charitable regulatory overlay could inhibit or even prevent charitable hybrids from achieving their charitable objectives, which ultimately should positively serve society and, as such, are desirable outcomes. Finally, legislatures in many states have declared a public policy that favors creation and adoption of these forms, and it is constitutionally incumbent on the executive branch to facilitate rather than impede that declaration, even arguably in those states that have not formally adopted the specific hybrid forms.
Processing and Structural Advantages of the Sylramic‐iBN SiC Fiber for SiC/SiC Components

The successful high-temperature application of complex-shaped SiC/SiC components will depend on achieving as high a fraction of the as-produced fiber strength as possible during component fabrication and service. Key issues center on a variety of component architecture, processing, and service-related factors that can reduce fiber strength, such as fiber-fiber abrasion during architecture shaping, surface chemical attack during interphase deposition and service, and intrinsic flaw growth during high-temperature matrix formation and composite creep. The objective of this paper is to show that the NASA-developed Sylramic-iBN SiC fiber minimizes many of these issues for state-of-the-art melt-infiltrated (MI) SiC/BN/SiC composites. To accomplish this, data from various mechanical tests are presented that compare how different high performance SiC fiber types retain strength during formation of complex architectures, during processing of BN interphases and MI matrices, and during simulated composite service at high temperatures.
Tooth hardness increases with zinc-content in mandibles of young adult leaf-cutter ants

A wide variety of arthropods and members of other phyla have elevated concentrations of Zn, Mn, other heavy metals and halogens in their jaws, leg claws, and other "tools" for interacting with the environment. While measured Zn concentrations reach 25% of dry mass in scorpion stings, concentrations are often lower than this and the enriched structures are not heavily biomineralized like vertebrate teeth and the radula of mollusks. For this reason, the degree to which the inorganic components of these structures modify their mechanical properties is in question. Here we address this problem by measuring hardness during the development of Zn accumulations in ant mandibles. We found that Zn is incorporated into the mandibular teeth of leaf-cutter ants during early adult life, reaching concentrations of about 16% of dry mass. We show that the hardness of the mandibular teeth increases nearly three-fold as the adults age and that hardness correlates with Zn content (r=0.91). We suggest that young adults rarely cut leaves partly because their mandibles are not yet rich in Zn. Zinc enrichment (along with enrichment by other heavy metals and halogens) may play an unrecognized role in the behavioral ecology and evolution of a wide variety of invertebrates.
Design and prototype fabrication of a 30 tesla cryogenic magnet

As part of its research program on advanced propulsion and power concepts, Lewis Research Center has designed and constructed a number of high-field magnets since 1960. These magnets have been made with water-cooled copper, liquid-neon-cooled aluminum, and superconductive windings. The maximum field of 20 T was obtained in an 11-cm bore magnet, cooled by free convection of liquid neon. A summary of much of this research and a projection of possible future work was presented by Laurence et al [1], who also discussed a concept for a steady-state 30-T magnet cooled by liquid neon. An analysis [2] showed that magnets with nonuniform structural support should be capable of fields in the 30-T range, and a design study of such a magnet was made [3]. Prok and Brown [3] showed that substantial increases in current density beyond that in the existing cryomagnets would result if the amount of stress-bearing structure is varied according to local requirements in the coils and if forced convection cooling is used. These changes allow the average conductor packing fraction to be nearly doubled and the current density in the conductor to be more than doubled. The average current density can thus be increased by about a factor of 4.
The Relativistic Electron Pair Theory of Matter and its Implications for Cosmology

Although atomic and nuclear physics have made enormous advances during the last century, there has been an increasing crisis in fundamental physical theory with regard to the nature of the ultimate constituents of matter which appear to have both particle and wave-like properties and occur in a bewildering variety of types and masses. Since there is now overwhelming evidence that the universe is expanding from a highly compact state that appears to have had the dimensions of a single proton or less, further progress in understanding the origin of the universe and its structure cannot be made until the problem of the nature of the fundamental particles is resolved.
Secondary malignant neoplasms in testicular cancer survivors

Abstract Background Testicular cancer is the most common cancer among men aged 15 to 40 years, and the incidence of testicular cancer is steadily increasing. Despite successful treatment outcomes and the rate of survival at 5 to 10 years being 95%, survivors can experience late effects of both their cancer and the treatment they received, including secondary malignant neoplasms (SMNs). We discuss the development of non–germ cell SMNs that develop after diagnosis and treatment of testicular cancer and their effect on mortality. Results Patients diagnosed with testicular cancer frequently choose postoperative surveillance if they are diagnosed with clinical stage I disease. These patients may experience an increased risk for developing SMNs following radiation exposure from diagnostic imaging. Similarly, radiotherapy for testicular cancer is associated with increased risks of developing both solid tumors and leukemia. Studies have reported that patients exposed to higher doses of radiation have an increased risk of developing SMNs when compared with patients who received lower doses of radiation. Patients treated with chemotherapy also experience an increased risk of developing SMNs following testicular cancer, though the risk following chemotherapy and radiation therapy combined is not well described. A large population-based study concluded that the rate ratios for both cancer-specific and all-cause mortality for SMNs among testicular cancer survivors were not significantly different from those of matched first cancers. Conclusions Although it is known that patients who receive adjuvant chemotherapy or radiotherapy or who undergo routine diagnostic or follow-up imaging for a primary testicular cancer are at an increased risk for developing SMNs, the extent of this risk is largely unknown. It is critically important that research be conducted to determine this risk and its contributing factors as accurately as possible.
Contemporary Groundwater Methane Production from Pleistocene Carbon

Relative to surface systems, microbial activities in groundwater five been poorly studied, especially with regard to methanogenesis. Past studies have reported high concentrations of CH 4 in groundwater in the late Wisconsinan till and Wisconsinan loess of central Iowa. The objectives of tits work were to assess whether CH 4 is presently produced in the till and loess, and, it so, to characterize the spatial variability of CH 4 production rates. Groundwater and sediment samples were collected at several locations within the Des Moines Lobe in central Iowa. Methane concentrations in groundwater ranged from 0.04 mol L -1 at 1 m to 2600 μmol L -1 at 7 m. Incubations of deep sediment obtained from core samples revealed active CH 4 production was occurring, although its variability was observed. Highest specific CH 4 production rates were associated with buried particulate C fragments of Wisconsinan age. Results of our study indicate methanogenesis is an active process in the sediments beneath the Des Moines Lobe, that the substrate for methanogenesis is of late Wisconsinan age, and that the high spatial variability of CH 4 production is controlled by the heterogeneous distribution of particulate organic C fragments in the glacial sediments
Attractors for the multilayer quasi-geostrophic equations of the ocean with delays

In this article, we study the multilayer quasi-geostrophic equations of the ocean with delays. We prove the existence of an attractor using the theory of pullback attractors.
Corporate Leverage, Bankruptcy, and Output Adjustment in Post-Crisis East Asia

Different levels of corporate leverage are used in this paper to help explain the wide range of post-crisis output adjustment across East Asia. In the model developed here, highly leveraged firms facing a cutoff of capital inflows are threatened by bankruptcy. These firms respond by eliminating investment and selling their capital goods-at a discount-to try to stay afloat. Lower investment and wasteful capital sales shrink the aggregate capital stock, trigger deflationary pressures, and contract overall output. The available data are broadly consistent with the assumptions and predictions of the model.
Spontaneous lipolysis in milk throughout the stages of lactation of individual cows.

Summary The milk from each of four cows maintained under controlled conditions was checked for spontaneous lipolysis four times a week during a complete lactation by the silica gel method. The average acid degree values (ADVs) were: Cow 1—0.57, Cows 2—0.75, Cows 3—1.25, and Cow 4—1.28. The ADVs increased as lactation progressed with Cows 2, 3, and 4. Samples that were rancid organoleptically were produced only by Cows 3 and 4. Most of these samples were taken during the last month of lactation. There was considerable week-to-week and cow-to-cow variation. The average p.m. ADVs of Cows 2 and 3 were significantly higher than the average a.m. ADVs.
Ordovician-Silurian tectonism in northern California:The Callahan event

Middle Ordovician to Early Silurian volcanism, plutonism, metamorphism, deformation, and sedimentation in the Yreka and Trinity terranes, eastern Klamath Mountains, northern California, are considered to be related phenomena that occurred in response to an episode of tectonism known as the Callahan event. A diverse array of evidence is used to construct a tectonic model for the Callahan event that involves a subduction zone, a magmatic arc, and a back-arc spreading center, and to show that tectonism likely occurred within the framework of the North American continental margin. Evidence pertaining to subduction polarity is meager, but is consistent with an eastward dip. The Callahan event represents the earliest Phanerozoic convergent-margin tectonic event recognized within the U.S. Cordillera.
Particulate air pollution and daily mortality in Detroit.

Particulate air pollution has been associated with increased mortality during episodes of high pollution concentrations. The relationship at lower concentrations has been more controversial, as has the relative role of particles and sulfur dioxide. Replication has been difficult because suspended particle concentrations are usually measured only every sixth day in the U.S. This study used concurrent measurements of total suspended particulates (TSP) and airport visibility from every sixth day sampling for 10 years to fit a predictive model for TSP. Predicted daily TSP concentrations were then correlated with daily mortality counts in Poisson regression models controlling for season, weather, time trends, overdispersion, and serial correlation. A significant correlation (P less than 0.0001) was found between predicted TSP and daily mortality. This correlation was independent of sulfur dioxide, but not vice versa. The magnitude of the effect was very similar to results recently reported from Steubenville, Ohio (using actual TSP measurements), with each 100 micrograms/m3 increase in TSP resulting in a 6% increase in mortality. Graphical analysis indicated a dose-response relationship with no evidence of a threshold down to concentrations below half of the National Ambient Air Quality Standards for particulate matter.
Demonstration of β amyloid protein-containing neurofibrillary tangles in parkinsonism-dementia complex on Guam

This report concerns the immunohistochemical demonstration of beta amyloid protein-containing neurofibrillary tangles (beta-NFTs) from patients with parkinsonism-dementia complex on Guam (PDC). Formalin-fixed paraffin-embedded tissue sections from the temporal lobe of nine PDC cases and the spinal cord of three were examined. An affinity-purified antibody to the N-terminal peptide sequence of beta amyloid protein was used. beta-NFTs were demonstrated in the temporal lobes of the three oldest individuals. Some senile plaques, probably a manifestation of ageing, were also seen. The beta-NFTs were most frequent in the entorhinal cortex. Senile plaques were invariably present in the vicinity of the beta-NFTs. Conversely, in the regions without senile plaques, even though numerous neurofibrillary tangles were identifiable with the modified Bielschowsky method, no beta-NFTs were seen. The density of beta-NFTs appeared to be proportional to that of senile plaques, none was seen in cases lacking senile plaques. No beta-NFTs were detected in the spinal cords. Our data suggest that beta-NFTs result from secondary beta amyloid deposition on certain neurofibrillary tangles.
The Development of Pediatric Nephrology

Pediatric nephrology, as a discipline, arose from descriptive studies of childhood glomerulonephritis in Europe and the field of pediatric metabolism in the United States. While pediatric scientists before 1950 were concerned with fluid and electrolyte metabolism, regulation of intracellular and extracellular fluid, acid-base homeostasis, and parenteral fluid therapy, the defined field of nephrology developed after the Second World War around six major advances: ACTH and glucocorticoid therapy for nephrotic syndrome; renal biopsy to diagnose glomerular disease; the role of immunologic factors in glomerular injury; the use of dialysis as renal replacement therapy; renal transplantation as the optimal form of therapy in children with end stage renal failure; and recognition of renal disease in the etiology of 80% of cases of childhood hypertension. These discoveries led to focused research, the definition of specific training in nephrology, establishment of an American, European, and an International Society of Pediatric Nephrology, as well as an American Sub-Board of Pediatric Nephrology, and the inception of a journal, Pediatric Nephrology, now in its 15th year. Major research themes have included developmental nephrology, transplantation immunology, and concerns about growth in children with renal disease. Many clinical entities have been described in detail, some of which are almost confined to children. The scientific basis of pediatric nephrology, ongoing patient care needs, and its technical aspects - renal biopsy, dialysis and transplantation - assure its continuing future as a major pediatric discipline on all continents.
Effect of Positional Substitution on the Optical Response of Symmetrically Disubstituted Azobenzene Derivatives

We have synthesized a series of symmetrically substituted p-diamidoazobenzenes, and we compare their steady-state and time-resolved responses to those of p-diaminoazobenzene and azobenzene. Our experimental and computational data indicate that the identity of the azobenzene ring substituent plays a significant role in determining the ordering of excited electronic states and the oscillator strengths for the various Sn ← S0 transitions. We find experimentally that the symmetric disubstitution of azobenzenes also influences the S0 isomerization surface, with the largest S0 barrier being found for the unsubstituted compound and the smallest barrier for p-diaminoazobenzene. We understand these data in the context of the relative electron-donating character of the para side groups.
A semiempirical theory of the optical activity of saccharides.

A semiempirical theory of optical activity of saccharides is developed that (a) goes beyond previous empirical treatments, (b) yields calculated NaD rotations which correlate well with experimental data, and (c) accounts for a characteristic c.d. band observed for polysaccharides in the vacuum u.v. spectrum.
Missing links: a survey of library systems department Web pages

Ironically, many library systems departments, even those of major research libraries, have no Web presence at all, or their pages are “hidden” beneath layers of links. Yet a well‐designed systems department Web page can be a valuable tool for users by offering all kinds of useful information about the system’s capabilities and quirks, best ways of access, what to do when problems arise, etc. This article surveys library systems departments Web pages and provides a closer look at some of the best of them.
Balance between cell−substrate adhesion and myosin contraction determines the frequency of motility initiation in fish keratocytes

Cells are dynamic systems capable of spontaneously switching among stable states. One striking example of this is spontaneous symmetry breaking and motility initiation in fish epithelial keratocytes. Although the biochemical and mechanical mechanisms that control steady-state migration in these cells have been well characterized, the mechanisms underlying symmetry breaking are less well understood. In this work, we have combined experimental manipulations of cell−substrate adhesion strength and myosin activity, traction force measurements, and mathematical modeling to develop a comprehensive mechanical model for symmetry breaking and motility initiation in fish epithelial keratocytes. Our results suggest that stochastic fluctuations in adhesion strength and myosin localization drive actin network flow rates in the prospective cell rear above a critical threshold. Above this threshold, high actin flow rates induce a nonlinear switch in adhesion strength, locally switching adhesions from gripping to slipping and further accelerating actin flow in the prospective cell rear, resulting in rear retraction and motility initiation. We further show, both experimentally and with model simulations, that the global levels of adhesion strength and myosin activity control the stability of the stationary state: The frequency of symmetry breaking decreases with increasing adhesion strength and increases with increasing myosin contraction. Thus, the relative strengths of two opposing mechanical forces—contractility and cell−substrate adhesion—determine the likelihood of spontaneous symmetry breaking and motility initiation.
Mechanism of the dimroth rearrangement in adenosine

Abstract An unambiguous mechanism for the Dimroth rearrangement has been established for adenosine by observation of isotopic [15N] nitrogen exchange between the exocyclic (N6) and endocyclic (1-) positions of the adenine ring which occurs simultaneously with the well documented methyl migration (from positions 1- to N6). The elucidation of this rearrangement by NMR techniques indicates that ring cleavage between the N1-nitrogen and C2-carbon atoms followed by 180° internal rotation, is the correct pathway.
Universality of Potts models with two- and three-site interactions

The $q$-state Potts model on the triangular lattice with both two- and three-spin interactions $K$ and $L$ (the Schick-Griffiths model) is shown to be equivalent to the $q$-state Potts model on a 3-12 lattice with only two-spin interactions ${J}_{1}$ and ${J}_{2}$. In particular, the ${J}_{1}g0$ and ${J}_{2}g0$ model is mapped into a Schick-Griffiths model for a range of the coupling parameters $K$ and $L$, so that the two models are in the same universality class. We also show that a recent conjecture by Tsallis on the critical point of the 3-12 model is incorrect.
Error diffusion in cell-oriented Fourier-transform computer-generated holograms to compensate for printing constraints

Error-diffused quantization has been applied to the generation of cell-oriented computer-generated Fourier transform holograms, resulting in reduced reconstruction errors. Improvements are demonstrated when applied to the algorithms of Lohmann, Lee and Burckhardt after invoking realistic constraints on the minimum size of the printable spot for an electrophotographic laser printer.
Humanized mouse models of FcR clearance in immune platelet disorders

Transgenic mouse lines expressing physiologic levels of human platelet Fc receptor (FcR) for IgG, Fc gamma RIIA, on platelets and macrophages were generated. Anti-CD9 antibody activated platelets of Fc gamma RIIA transgenic mice and, following injection in vivo, caused rapid and severe thrombocytopenia compared with nonactivating antiplatelet antibody. Anti-CD9 injected in Fc gamma RIIA transgenic mice crossed with FcR gamma-chain knockout (gamma-KO) mice caused thrombosis and shock in all mice, and death in 16 of 18 mice. Histologic examination of lung vasculature of anti-CD-treated Fc gamma RIIA transgenic x gamma-KO mice showed extensive platelet-fibrin thrombi. Taken together, these observations suggest that in Fc gamma RIIA transgenic x gamma-KO mice there is an important interplay of intravascular platelet activation and splenic clearance. Reduction of splenic clearance surgically or functionally also facilitated anti-CD-9-mediated shock in Fc gamma RIIA transgenic mice. Thus, antibodies that activate platelets in an Fc gamma RIIA-dependent manner lead to thrombosis, shock, and death. These mouse model findings have implications for human immune-mediated thrombocytopenic disorders. Genetic factors may be important in the interindividual variability seen clinically, and with nonactivating platelet antibody the spleen is largely responsible for the thrombocytopenia. This is likely the case in typical idiopathic thrombocytopenic purpura (ITP). For several other immune thrombocytopenic disorders, the spleen probably plays a second, protective role in removing antibody-coated platelets from the circulation.
Infinite paths that contain only shortest paths

Let Γ be an infinite, locally finite, connected simple graph. A one-way (resp. two-way) infinite path of which every finite subpath is a shortest path is called a halfaxis (resp. an axis). The following are proved: (1) Given any vertex x and any end e of Γ, there exists a halfaxis belonging to e which originates at x (thus sharpening a classical resut of D. Konig, in “Theorie der endlichen und unendlichen graphen”, Akad. Verlagsgesellschaft, Leipzig, 1936); (2) every pair of distinct ends of Γ contains a pair of halfaxes whose union is an axis of Γ; (3) if H is a halfaxis and y is a vertex not on H, then some halfaxis originating at y meets H. If Γ is vertex-transitive, we prove: (4) every vertex lies on an axis, and (5) the complement of every axis has no finite component. We investigate vertex-transitive graphs having the following property: if A is an axis and y is a vertex not on A, then there exists an axis through y disjoint from A. Graphs with connectivity equal 1 and having this property are characterized.
The Infrared Absorption of Some Organic Liquids Under High Resolution

For the purpose of comparing the Raman effect with infrared absorption spectra, the following organic liquids have been measured from 3.1\ensuremath{\mu} to 3.6\ensuremath{\mu}: benzene, toluene, ortho-, meta- and para-xylene, ethyl-, butyl-, monochlor-, and monobrombenzene. The spectrometer employed an echelette grating, which had 3600 lines per inch, and which concentrated the energy of a Nernst filament into the region which was investigated. The dispersion of the instrument was such that with the slits each 0.25 mm in width, one "slit width" was approximately 25A". The calibration was obtained in terms of the positions of the 5461 line from an auxiliary Hg arc, and the wave-lengths as given are considered accurate to \ifmmode\pm\else\textpm\fi{}0.003\ensuremath{\mu}. In every case the bands in this region, due to the C-H vibration, which have hitherto been reported only under low dispersion have been resolved into many component parts. The 3.25\ensuremath{\mu} band of benzene was resolved into three equally strong components lying at 3.231, 3.253 and 3.291\ensuremath{\mu} respectively. The shifts of these bands caused by the various substitutions were studied, and in no case was a shift of over 0.01\ensuremath{\mu} found.
DNA unwinding induced by zinc finger protein binding

Zinc finger domains of the Cys2His2 type are found in a large number of eukaryotic proteins. Various proteins containing these domains have been shown to bind specifically to DNA, RNA, and DNA-RNA hybrids. Structural studies of zinc finger protein-DNA complexes have revealed that the DNA molecules are underwound relative to canonical B-form. It has not been clear if zinc finger proteins recognize preexisting underwound conformations of DNA or if they induce such conformations upon binding. We report that the DNA binding domains of Sp1 and several designed zinc finger proteins unwind DNA upon binding. The extent of unwinding is consistent with that observed in zinc finger protein-DNA cocrystal structures. These DNA deformations may be important in determining overall binding affinities as well as influencing binding site preferences. Furthermore, changes in DNA conformation upon zinc finger protein binding may affect protein-protein interactions important for transcriptional regulation and other activities of zinc finger proteins.
Organic acidemia in a young cat associated with cobalamin deficiency

Objective: To describe a case of severe metabolic acidosis and encephalopathy secondary to cobalamin (Cbl) deficiency in a young cat. Case summary: A 4-year-old spayed female domestic short hair cat weighing 2.5 kg, presented with a 2-day history of neurological signs referable to the cerebrum. The cat was evaluated for similar episodes twice before, however, no definitive diagnosis was made for either visit. On presentation the cat was minimally responsive and had a metabolic acidosis and ketonuria with no apparent reason, such as lactic acidosis or diabetic ketoacidosis. The patient was diagnosed postmortem with an organic acidemia secondary to low Cbl levels. New or unique information provided: The purpose of this report is to alert emergency clinicians to be suspicious of an organic acidemia in any case of metabolic acidosis and ketonuria that cannot be explained. Early identification of inherited organic acidemias in domestic animals may allow prompt and appropriate treatment of these conditions.
Column Procedures for the Salt Fractionation of Enzyme Preparations

Two procedures for fractionating enzyme preparations on a column, somewhat different from the previously described chromatopile1, have been found useful in preliminary tests.
Low Btu Coal Gas Combustion in High Temperature Turbines

This paper defines the combustion consequences of burning low Btu coal gas in high temperature gas turbines. It identifies the limits of their application regarding the heating value and its thermodynamic constraints on turbine firing temperature, operating flammability limits, product carbon monoxide, oxides of nitrogen and combustor turndown ratio. Sensitivity to reaction zone radiation and effects on combustor hot gas path flow area are discussed. The effect of these constraints on the conceptual design of a combustor is described herein. The example discussed is the sectoral combustor which was designed under contract to the Department of Energy for use in the High Temperature Turbine Technology program. The sectoral combustor is to be fired on coal gas to within 250 C of the homogeneous, adiabatic, stoichiometric flame temperature limit.Copyright © 1980 by ASME
Projection-operator approach to a renormalized kinetic theory

A renormalized kinetic theory is developed for the classical phase-space density correlation function by means of the projection-operator formalism. The technique consists of introducing a sequence of projection operators which project onto spaces involving successively larger numbers of particles. The first such operator is the Akcasu-Duderstadt projection operator, which yields a generalized Langevin equation (kinetic equation) for the correlation function. The structure of the memory function in this equation suggests a second projection operator, which is shown to lead to a two-body kinetic equation for one factor in the memory function. Further projection operators proceed similarly, and the result is a continued-fraction expansion of the correlation function. This expansion is renormalized in the sense that the interparticle potential always drops out in favor of static correlation functions. The expansion is shown to be equivalent to the result of the kinetic theory formulated by Gross. The analogous development for self-correlations is also given.
Regional development of norepinephrine, dopamine-β-hydroxylase and tyrosine hydroxylase in the rat brain subsequent to neonatal treatment with subcutaneous 6-hydroxydopamine

Abstract Neonatal rats were injected subcutaneously with 100 mg/kg 6-hydroxydopamine (6-OHDA), or vehicle, on postnatal days 1, 2 and 3. At several times thereafter, determinations of tyrosine hydroxylase (TOH)_and dopamine-β-hydroxylase (DBH) activities, and norepinephrine (NE) concentration were made in the parietal cortex, cerebellum and pons-medulla in order to assess the extent of initial noradrenergic degeneration induced, and the rate of any ensuing regeneration. By the day following completion of the treatment (postnatal day 4), degeneration of noradrenergic terminals in the parietal cortex and cerebellum was very extensive, with NE levels and DBH activities reduced by more than 80%, and TOH activities reduced by 50%. In the parietal cortex noradrenergic degeneration remained virtually complete; at 9 and 70 days postnatal NE concentration and DBH and TOH activities were all decreased by more than 90–95%. In the cerebellum a progressive regeneration and apparent sprouting of NE fibers was observed. By postnatal day 9, NE, DBH and TOH in this tissue had all recovered to near control levels, and by day 70 these measures exceeded control levels by 95%, 115% and 50% respectively. In the pons-medulla, the initial effect of 6-OHDA on any of the measured parameters was negligible. By postnatal day 9 an increase in NE concentration was apparent, which increased further by day 70 to surpass the control level by 70%. At this same time DBH activity was increased by only 15% and TOH activity was unchanged. Separate analysis of the rostral half of the pons, which contains the locus coeruleus, revealed that on day 70 NE and DBH levels were increased much more substantially than in the whole pons-medulla, and TOH activity was also significantly elevated. This data indicates that the initial amount of degeneration induced by the 6-OHDA treatment is similar in both the parietal cortex and cerebellum, but regeneration proceeds only in the cerebellum. This suggests that noradrenergic fiber growth and regeneration in each target tissue is under independent regulation, possibly by the individual target neurons themselves.
Dream report length is more dependent on arousal level than prior REM duration

Twenty two young adult subjects (Ss) were monitored for 2 consecutive nights in the sleep laboratory. Each S was awakened three times per night: at sleep onset and during the second (REMP2) and fourth (REMP4) REM periods. Length of time in each REMP prior to awakening was either 5 or 10 min, counterbalanced on successive nights. Sleep mentation reports were obtained by standardized interview and scored for total word count (TWC). TWC after 5 min of prior REM sleep did not differ significantly from TWC after 10 min of prior REM sleep. However, mean TWC from REMP4 awakenings was almost twice that from REMP2 awakenings. These findings are consistent with the hypothesis that the amount of recall from experimental REM awakenings depends on central arousal level and its effects on mnemonic processes.
Rhabdoviruses and the Cellular Ubiquitin-Proteasome System: a Budding Interaction

The matrix (M) proteins of vesicular stomatitis virus (VSV) and rabies virus (RV) play a key role in both assembly and budding of progeny virions. A PPPY motif (PY motif or late-budding domain) is conserved in the M proteins of VSV and RV. These PY motifs are important for virus budding and for mediating interactions with specific cellular proteins containing WW domains. The PY motif and flanking sequences of the M protein of VSV were used as bait to screen a mouse embryo cDNA library for cellular interactors. The mouse Nedd4 protein, a membrane-localized ubiquitin ligase containing multiple WW domains, was identified from this screen. Ubiquitin ligase Rsp5, the yeast homolog of Nedd4, was able to interact both physically and functionally with full-length VSV M protein in a PY-dependent manner. Indeed, the VSV M protein was multiubiquitinated by Rsp5 in an in vitro ubiquitination assay. To demonstrate further that ubiquitin may be involved in the budding process of rhabdoviruses, proteasome inhibitors (e.g., MG132) were used to decrease the level of free ubiquitin in VSV- and RV-infected cells. Viral titers measured from MG132-treated cells were reproducibly 10- to 20-fold lower than those measured from untreated control cells, suggesting that free ubiquitin is important for efficient virus budding. Last, release of a VSV PY mutant was not inhibited in the presence of MG132, signifying that the functional L domain of VSV is required for the inhibitory effect exhibited by MG132. These data suggest that the cellular ubiquitin-proteasome machinery is involved in the budding process of VSV and RV.
The EPR spectrum of a manganese center observed in γ-irradiated (CH3)3SnMn(CO)5 single crystals☆

Abstract An EPR spectrum detected in γ-irradiated single crystals of trimethyltin-manganese pentacarbonyl was analyzed in terms of anisotropic interactions between a single unpaired electron, a manganese nucleus, and the magnetic field. At 100 K, the principal components of the g and 55 Mn-hyperfine tensors are 2.0399, 2.0279, 2.0018 and 84.1 MHz, 106.3 MHz, 162.3 MHz, respectively. The free radical is believed to be (CH 3 ) 3 SnMn(CO) 4 − , formed from the parent carbonyl by electron addition and loss of an equatorial ligand.
Prognosis of Adenocarcinoma Arising in Barrett’s Esophagus

Abstract Background . The rising incidence of adenocarcinoma of the esophagus, as well as its association with Barrett's esophagus, has been reported previously. We report our experience in treating patients with adenocarcinoma arising in Barrett's esophagus. Methods . A retrospective review was performed of 70 consecutive patients with adenocarcinoma of the esophagus treated between November 1988 and April 1996 with preoperative chemoradiation and resection. Demographics, pathologic features, and survival were compared with patients who developed adenocarcinoma of the esophagus without Barrett's. Statistical analyses was performed using Student's t test, Fisher's exact test, and Kaplan-Meier where appropriate. Results . Thirty-two (46%) patients had adenocarcinoma arising in Barrett's esophagus. During the last 4 years, 72% (23 of 32) of patients with adenocarcinoma had coexistent Barrett's. No differences in patients with or without Barrett's with regard to age, sex, race, tumor location, preoperative chemotherapy, type of operation, or operative stage were observed. Tumors in patients with Barrett's were larger ( p = 0.017), had better differentiation ( p = 0.002), and were less likely to have a complete response to preoperative chemoradiation ( p = 0.05). Actuarial survival, however, was better in the group with associated Barrett's esophagus ( p = 0.033). Conclusions . The incidence of adenocarcinoma of the esophagus arising in Barrett's esophagus appears to be increasing. It may be distinct clinically and biologically from adenocarcinoma of the esophagus that does not develop in association with Barrett's epithelium. Long-term survival was better in our patients with adenocarcinoma associated with Barrett's esophagus.
Serum triple-marker screening in in vitro fertilization and naturally conceived pregnancies.

Objective To determine whether results of second-trimester maternal serum triple-marker screening for Down syndrome and open neural tube defects in singleton pregnancies conceived from in vitro fertilization (IVF) differ from those of pregnancies conceived spontaneously. Methods The screen-positive rates and triple-marker levels of patients conceiving singleton pregnancies by IVF were compared to age-adjusted standards. Results Sixty-nine singleton IVF pregnancies with maternal serum screening were identified. Twenty-one (30.4%) of the 69 IVF singleton pregnancies had a positive screen for Down syndrome compared with a 14.4% expected screen-positive rate for the maternal age distribution in our observed sample ( P = .013). The screen-positive rate for open neural tube defects in the measured population was similar to anticipated values based on historic controls (5.8% in IVF patients versus 5.3% in the total population). The median levels of the triple markers were 0.95 multiples of the median (MoM) for alpha-fetoprotein (AFP), 0.90 MoM for unconjugated estriol (E3), and 1.22 MoM for hCG. Conclusion The increased hCG levels as well as the slightly lower AFP and unconjugated E3 levels may contribute to the higher Down syndrome screen-positive rate in this IVF singleton population. These results may be due to the number of embryos transferred, the maternal hormonal environment of the IVF process, or other factors. Pregnancies conceived by IVF may be twice as likely to have a positive maternal serum screening test. As additional data are collected, corrected standards should be determined.
Lessons from Roman Cement and Concrete

Although masonry and lime mortars had been used for centuries by earlier civilizations, the Romans were the first to extensively use naturally occurring volcanic earth to make hydraulic cement. The volcanic powder named “pulvis puteolanis,” found near the town of Puteoli near Naples (now Pozzouli), was used to build magnificent structures. The use of this hydraulic cement in masonry and concrete greatly expanded civil engineering possibilities. The Roman engineer Vitruvius, writing in The Ten Books on Architecture, described the careful materials selection, proportioning, and workmanship that was critical to the performance of Roman concrete. Masonry and coarse and fine aggregates were carefully selected for durability. Hydraulic cement concrete was used extensively for constructing bridge piers and harbor jetties. One of the greatest examples of Roman concrete construction was the dome of the Pantheon, with its 43.4-m span. The vast system of aqueducts also made extensive use of hydraulic cement. This pa...
Prototyping real-time vision systems: an experiment in DSL design

Describes the enhancement of XVision, a large library of C++ code for real-time vision processing, into FVision (pronounced "fission"), a fully-featured domain-specific language (DSL) embedded in Haskell. The resulting prototype system substantiates the claims of increased modularity, effective code reuse and rapid prototyping that characterize the DSL approach to systems design. It also illustrates the need for judicious interface design: relegating computationally expensive tasks to XVision (pre-existing C++ components) and leaving modular compositional tasks to FVision (Haskell). At the same time, our experience demonstrates how Haskell's advanced language features (specifically, parametric polymorphism, lazy evaluation, higher-order functions and automatic storage reclamation) permit a rapid DSL design that is itself highly modular and easily modified. Overall, the resulting hybrid system exceeded our expectations: visual tracking programs continue to spend most of their time executing low-level image processing code, while Haskell's advanced features allow us to quickly develop and test small prototype systems within a matter of a few days, and to develop realistic applications within a few weeks.
Evidence for Structure Sensitivity in the Thermally Activated and Photocatalytic Dehydrogenation of 2-Propanol on TiO2

The reaction CH3CHOHCH3 + 1/2O2 → CH3COCH3 + H2O has been studied on the (110) and (100) planes of TiO2 using molecular beam techniques. We find that the reaction can proceed through thermally activated and photocatalytic pathways to produce acetone and propene. On the (110) surface, in the absence of light the total reaction probability for an incident 2-propanol molecule, Preaction = Pacetone + Ppropene, is 0.03. Pacetone is less than 0.01. In the presence of light with hυ > 3.2 eV, Ppropene ∼ 0, and Pacetone = 0.15 and the reaction proceeds readily for T < 180 K, indicating that it is not thermally activated. On the (100) surface, we also observe thermally activated and photocatalytic pathways. However, the branching ratio is very different than that on the (110) surface. We observe that, for the thermally activated channel, Preaction = 0.13, and for the photocatalytic pathway, Preaction = Pacetone = 0.03. Whereas the (110) surface shows a high selectivity for the photocatalytic pathway, the (100) surf...
Comparison of Reversed, Nonreversed Translocated, and In Situ Vein Grafts in Arterial Revascularization: Techniques, Cumulative Patency, Versatility, and Durability.

Since Carrell and Guthrie used the reversed saphenous vein graft for arterial reconstruction in 1906 [1], this technique has undergone several technical modifications to earn its popularity and credibility [2–4]. Vein preparation has also been refined to attain optimal preservation of histocytologic integrity in order to improve graft patency [6–12]. Notwithstanding the periodical enthusiasm to substitute saphenous vein with biologic [13–15] or prosthetic grafts [16–18], or prosthetic graft with a venous cuff [19–21] for expedience, autogenous vein graft remains the preferred conduit and the gold standard in vascular bypass operations. Autogenous vein graft has been subjected to intense scrutiny for optimal morphologic preservation and identification of etiologic factors contributing to segmental fibrosclerosis and aneurysmic degeneration. The anatomic orientation of reversed versus nonreversed vein graft has also been extensively evaluated for their role in long-term graft function and patency [22]. Despite the initial nongermane attitude toward vein preparation, there is evidence to support the importance of the pH, osmolality, osmolarity, and the duration of storage in media, in the preservation of the integrity of cellular and extracellular elements of the vein grafts [5,9,10,23–25]. It is well established that durability and long-term patency of a vein graft is frequently the by-product of at least four vital elements: vein quality, vein preparation, anatomic orientation and surgical technique.
Service Path Attribution Networks (SPANs): A Network Flow Approach to Ecosystem Service Assessment

Ecosystem services are the effects on human well-being of the flow of benefits from ecosystems to people over given extents of space and time. The Service Path Attribution Network (SPAN) model provides a spatial framework for determining the topology and strength of these flows and identifies the human and ecological features which give rise to them. As an aid to decision-making, this approach discovers dependencies between provision and usage endpoints, spatial competition among users for scarce resources, and areas of highest likely impact on ecosystem service flows. Particularly novel is the model’s ability to quantify services provided by the absence of a flow. SPAN models have been developed for a number of services (scenic views, proximity to open space, carbon sequestration, flood mitigation, nutrient cycling, and avoided sedimentation/deposition), which vary in scale of effect, mechanism of provision and use, and type of flow. Results using real world data are shown for the US Puget Sound region.