cssi/SciSciGPT-SciSciNet huggingface dataset:
Episodic construction of batholiths: Insights from the spatiotemporal development of an ignimbrite flare-up

Abstract Using the canon that large silicic volcanic fields are the surface manifestation of batholith formation at depth as a departure, we examine what the spatiotemporal pattern of the 10–1 Ma ignimbrite flare-up of the Altiplano–Puna Volcanic Complex of the Central Volcanic Zone of the Andes reveals about the formation of its upper-crustal plutonic underpinnings. The volume–time relations of major ignimbrite eruptions reveal an episodic pattern of eruptions at rates much higher than those typical of continental arcs. At least 10,000 km 3 of dacitic magma were erupted in four pulses of eruptions at ∼ 10, 8, 6, and 4 Ma that show increasing intensity and definition with time and then catastrophic diminution after 4 Ma. Calculated rates of extrusion during the pulses (0.004 to 0.012 km 3 yr − 1 ) are up to an order of magnitude higher than the average rate for the flare-up and continental silicic volcanic provinces in general (0.001 km 3 yr − 1 ). Peak intrusion rates of 0.012 to 0.06 km 3 yr − 1 ) calculated assuming a range of 3:1 to 5:1 plutonic:volcanic ratio are consistent with calculated rates of granite pluton formation. These spatiotemporal patterns suggest that a composite upper-crustal granodiorite batholith was built episodically in pulses characterized by episodic rates of intrusion that became more intense and defined in time. This pattern can be understood in the framework of a model where the mechanical strength of the crust evolves in response to magmatism through time. We propose that the APVC flare-up records a positive feedback between the mantle input, magma production, and upward migration of the magmatic system that results in a thermomechanical evolution that promotes the accumulation of larger bodies of dacite magma in the upper crust with time. The record from long-lived nested calderas suggests that locally the sub-volcanic batholith may be constructed of plutons that themselves are composite bodies built over several million years. We find support for our ideas in the Mesozoic Sierra Nevada Batholith of California.
Curvature Elasticity of Block Copolymers and the Structure of Emulsified Polymer Blends

We consider the curvature elastic properties of a layer of block copolymer at the interface between two incompatible homopolymers. We focus on the relation between the relative lengths of the blocks and the elastic properties of the interfacial layer which determines the phase behavior. The curvature elastic moduli K andK , as well as the spontaneous curvature, c0, are obtained. The curvature free energy is used to predict the relative stability of spherical, cylindrical, lamellar, and ordered bicontinuous saddle-shaped structures as functions of concentration and polymer properties.
Simplified synthetic TMC-95A/B analogues retain the potency of proteasome inhibitory activity.

The proteasome regulates diverse intracellular processes, including cell-cycle progression, antigen presentation, and inflammatory response. Selective inhibitors of the proteasome have great therapeutic potential for the treatment of cancer and inflammatory disorders. Natural cyclic peptides TMC-95A and B represent a new class of noncovalent, selective proteasome inhibitors. To explore the structure-activity relationship of this class of proteasome inhibitors, a series of TMC-95A/B analogues were prepared and analyzed. We found that the unique enamide functionality at the C-8 position of TMC-95s can be replaced with a simple allylamide. The asymmetric center at C-36 that distinguishes TMC-95A from TMC-95B but which necessitates a complicated separation of the two compounds can be eliminated. Therefore, these findings could lead to the development of more accessible simple analogues as potential therapeutic agents.
Algorithm 421: complex gamma function with error control [S14]

This Fortran program computes either the gamma function or the loggamma function of a complex variable in double precision. In addition, it provides an error estimate of the computed answer. The calling sequences are: CALL CDLGAM (Z, W, E, 0) for the loggamma, and CALL CDLGAM (Z, W, E, 1) for the gamma, where Z is the double precision complex argument, W is the answer of the same type, and E is a single precision real variable. Before the call, the value of E is an estimate of the error in Z, and after the call, it is an estimate of the error in W.
Ubiquitous production of macrophage migration inhibitory factor by human gastric and intestinal epithelium.

Abstract Background & Aims: Macrophage migration inhibitory factor (MIF) inhibits macrophage migration and has pleiotropic activities on immune and inflammatory responses, cell growth, and glucose metabolism. MIF is produced by T cells, macrophages, and endothelial cells. Because intestinal epithelial cells produce mediators important for regulating mucosal immune and inflammatory responses, we sought to determine if these cells produce MIF. Methods: MIF expression was determined by immunostaining of human intestinal mucosa, intestinal xenografts, and cultured cells. MIF protein levels were quantitated by enzyme-linked immunosorbent assay and immunoblot analysis, messenger RNA was assessed by real-time reverse-transcription polymerase chain reaction, and functional activity was assessed by enzymatic and migration assays. Results: MIF was abundantly expressed in vivo in gastric, small intestinal, and colonic epithelium and in epithelium lining human intestinal xenografts. MIF was also constitutively expressed at the messenger RNA and protein level by several cultured colon and gastric epithelial cell lines, and its expression in those cells was not up-regulated by the proinflammatory cytokines interleukin 1α, tumor necrosis factor α, or interferon gamma. Epithelial MIF from cultured cells was released predominantly from the apical side after Salmonella infection, had tautomerase activity, and arrested macrophage migration. Conclusions: Human intestinal epithelial cells are a major source of MIF, a molecule that can regulate macrophage migration, inflammation, and cell metabolism. GASTROENTEROLOGY 2002;122:667-680
Pressure ulcer and mortality in frail elderly people living in community

Pressure ulcer is one of the most common, disruptive and often disabling conditions affecting frail older people. Purposes of the present study are to ascertain the prevalence of pressure ulcer and to explore the relationship between pressure ulcer and the risk of 1-year all-cause mortality in a large population of frail and very old people living in community. This was an observational cohort study. We analyzed data from the Italian Silver Network Home Care project that collected data on patients admitted to home care programs. A total of twelve home health agencies participated in such project evaluating the implementation of the minimum data set for home care (MDS-HC) instrument. A total of 3,103 patients were enrolled in the present study. The prevalence of patients with pressure ulcer was about 18%. During a follow-up of 12 months from the initial MDS-HC assessment, 160 subjects (29%) died in the pressure ulcer group compared to 368 subjects (14%) in the group of patient without pressure ulcer (p<0.001). After adjusting for age, gender and for all the significantly different variables between subjects with and without pressure ulcer at baseline, subjects with pressure ulcer were more likely to die compared to those without pressure ulcer (RR=1.92; 95% Cl 1.52-2.43).
Using noise and chaos control to control nonchaotic systems.

Here we show that chaos control techniques can be used to stabilize unstable periodic orbits in a nonchaotic system provided additive noise can be utilized (1) to determine the local dynamics of a chosen orbit, and (2) to move the system's trajectory into the neighborhood of the orbit so that control can be initiated. Using these techniques, we demonstrate that the qualitative dynamics of a nonchaotic system can be altered without using large controls or large parameter shifts. Unlike classical control methods, this approach requires no knowledge of the underlying system equations. (c) 1995 The American Physical Society
Asphalt Permeability Testing in Virginia

Because of high air voids, long-lasting damp spots on pavement surfaces, and problems that other states have had with permeable coarse Superpave mixes, the Virginia Department of Transportation (VDOT) decided to investigate the permeability of its Superpave mixes. As part of this study, VDOT also tested other asphalt mixes. Falling-head permeability tests were performed on pavement cores to determine the general permeability of the mixes. The permeability of some of the pavement cores was compared with the permeability of specimens made in the laboratory through the use of mixtures sampled during construction to determine whether laboratory specimens could be used to predict pavement permeability. The primary purpose of this investigation was to determine the general magnitude of permeability for mixes being used by VDOT, with an emphasis on Superpave mixes. A large percentage of the field cores contained excessive voids, resulting in excessive permeability. Each mix had a unique voids-permeability relati...
The conversion of coal to petroleum: its German roots

Abstract This paper [1] examines the work of Friedrich Bergius, the inventor of high-pressure coal hydrogenation in the period 1910–1925. The paper traces Bergius's development of high-pressure coal hydrogenation from a laboratory-scale process to a small factory-size operation at Rheinau-Mannheim, Germany. Bergius carried out several thousand experiments, requiring the testing of more than 200 different kinds of coal, before bringing his hydrogenation process to a successful conclusion. In his factory, where he spent several million dollars in research and employed 150 men, Bergius demonstrated for the first time the possibility of establishing a German synthetic petroleum industry. This history of coal hydrogenation shows the difficulties Bergius faced in expanding his process from the laboratory-scale to a small industry. The major problems he confronted and successfully solved were: (1) providing enough hydrogen gas to convert coal into synthetic petroleum, (2) working at the high pressures required for the conversion, and (3) regulating the reaction's temperature. Because the reaction was exothermic and sensitive to temperature change, accurate temperature control was a major accomplishment. In spite of Bergius's successes, two other problems remained unsolved. Bergius did not investigate the influence of different catalysts on the hydrogenation reaction, and his process was a one-stage operation; the hydrogenation of coal and the splitting of the products formed took place in one step. This procedure resulted in a smaller amount of the reaction products splitting into gasoline-size molecules. The gasoline was, in addition, of low quality, and without refining it could not compete with gasoline obtained from natural petroleum. The major emphasis in the study of the early German coal hydrogenation programs has been on the scientific and technological developments that Bergius encountered, but not to the exclusion of the social, political, and economic factors that accompanied its rise. It illustrates, for example, the difficulties that Bergius, scientist and entrepreneur, faced in continually trying to raise money to keep his project alive and his efforts to market his product by entering into different patent arrangements in Germany and internationally.
Reexamination of the monolayer properties of a fluorescein amphiphile in Langmuir and Langmuir-Schaefer films

We herein report a reexamination of Langmuir and Langmuir−Schaefer films of (5-octadecanoylamino)fluorescein (ODFL) prepared from three different spreading solvents: ethanol (EtOH), CHCl3/EtOH (9:1, v/v), and CHCl3/trifluoroacetic acid (9:1, v/v). It was found that the limiting molecular area of the ODFL monolayer is strongly spreading solvent-dependent, ranging from 15 to 64 A2molecule-1. These results strongly disgree with reported results from Tsukanova et al. (Langmuir 2000, 16, 1167) of the same molecule by using ethanol as spreading solvent. Our study also shows that this fluorescein amphiphile significantly aggregates at the air−water interface. The UV−vis spectra of the monolayer are redshifted about 20 nm compared to that in the solution. Fluorescence quenching was observed from both a pure ODFL monolayer and a monolayer of ODFL mixed with stearic acid. However, fluorescence emission spectra were readily observed from mixed monolayers of ODFL with three synthetic peptide lipid molecules. This st...
Application of anion-exchange resin to remove lipophilic chelates from liposomes

Lipophilic chelates such as 8-hydroxyquinoline, acetylacetone, and tropolone are useful to load high levels of radioactive cations into the inner aqueous compartments of liposomes for investigating the fate of liposomes by the technique of gamma imaging or gamma-ray perturbed angular correlation measurements. However, if lipophilic chelates are not completely removed from liposomes the very same lipophilic chelates can also cause leakage of the entrapped cations from liposomes. Thus, it is essential to make sure that all the lipophilic chelates are removed from liposomes after the loading process. The results of the present study show that more than 99.85% of acetylacetone in liposomal suspension can be removed by a minicolumn of AG1-X8 (phosphate form) anion exchange resin. Virtually all the 8-hydroxyquinoline and tropolone in liposomal suspension are adsorbed tightly to the resin. The procedure is rapid, and the dilution of liposomes is minimal. For experiments involving high levels of gamma-emitting radionuclides, the cleaning up process of removing lipophilic chelates from liposomes can be conveniently operated behind a lead glass.
Dunk, Dunkless and Re-dunk Tectonics: A Model for Metamorphism, Lack of Metamorphism, and Repeated Metamorphism of HP/UHP Terranes

High-pressure metamorphic terranes form when slivers of continental crust are pulled into the mantle by previously subducted oceanic lithosphere. Old, cold lithosphere subducts into the mantle at steep angles, dragging sialic crust to deep levels, quickly followed by steep, rapid exhumation. Young thin lithosphere subducts at shallow angles, pulling crustal slabs slowly into the shallow mantle, followed by slow exhumation, retrogression, and melting. Terranes that follow inboard-dipping subduction zones will subduct once, and will be overprinted by subsequent subduction and collisions. Terranes above outboard-facing subduction zones will be underthrust by the continental margin. Subsequent collisions will result in the re-subduction of an increasingly complex continental margin characterized by previously accreted terranes.
Knowledge and deductive closure

The question whether epistemological concepts are closed under deduction is an important one since many skeptical arguments depend on closure. Such skepticism can be avoided if closure is not true of knowledge (or justification). This response to skepticism is rejected by Peter Klein and others. Klein argues that closure is true, and that far from providing the skeptic with a powerful weapon for undermining our knowledge, it provides a tool for attacking the skeptic directly. This paper examines various arguments in favor of closure and Klein's attempted use of closure to refute skepticism. Such a refutation of skepticism is mistaken. But the closure principle is in any case false, so the skepticism that depends on it is undermined. The appeal of the closure principle derives from a failure to recognize an important feature of our epistemological concepts, namely, their context relativity.
Merely a Defense? The Variety of Religious Means and Ends

This paper examines the validity of the view that religion is a defense, a mechanism designed to reduce tension by avoiding a threatening situation rather than confronting it. Empirical and theoretical literature is reviewed suggesting that tension reduction is one but not the only motivation for religious involvement. Additional evidence also indicates that religion is not simply a form of denial, not merely a passive form of coping, and not solely associated with resistance to social change. In contrast to the religion as defense stereotype, religion appears to serve many different purposes and does so in many different ways. It may be more helpful to think of religion as a way of coping, effectively or ineffectively, with life's most difficult problems than as a defensive reaction to trouble. This more differentiated perspective leads to more refined questions about the factors that determine the shape of religion. It also underscores the need for a greater appreciation of the potentially helpful and harmful roles religion can play in the life of the individual and the community. Finally, it points to new opportunities for collaboration between those psychological and religious communities that share a respect for diversity, the dignity of the individual, and social justice.
Direct association of the HPV16 E7 oncoprotein with cyclin A/CDK2 and cyclin E/CDK2 complexes

The human papillomavirus (HPV) E7 oncoprotein has been shown to associate with cyclin/CDK2 complexes. Here we present evidence that HPV E7 proteins can associate with cyclin A/CDK2 and cyclin E/CDK2 complexes in cells that lack retinoblastoma tumor suppressor family members through sequences outside of the core retinoblastoma tumor suppressor binding site. Moreover, we show that HPV16 E7 can directly associate with cyclin A/CDK2 and cyclin E/CDK2 complexes. These results suggest that cyclin/CDK2 complexes may be components of HPV E7-associated cellular complexes that do not contain retinoblastoma tumor suppressor family members.
Why Leadership Matters to Internal Communication: Linking Transformational Leadership, Symmetrical Communication, and Employee Outcomes

This study examines how organizational leadership influences excellent internal communication by building the linkage between transformational leadership, symmetrical communication, and employee attitudinal and behavioral outcomes. The results showed that transformational leadership positively influences the organization's symmetrical communication system and employee–organization relationships. The effects of transformational leadership on employee relational outcomes are partially mediated by symmetrical internal communication. Symmetrical communication demonstrates large positive effect on the quality of employee–organization relationships, which in turn leads to employee advocacy. Effects of symmetrical internal communication on employee advocacy are fully mediated by employee–organization relationships. Significant theoretical and practical implications are discussed.
On optimal placement of molecules in the unit cell

There are currently no rules for a unified, standard way of placing macromolecular structures in the crystal lattice. An analysis of all possible symmetry-equivalent representations of molecular structures in various space groups leads to the concept of the anti-Cheshire symmetry and suggests that the center of a unique structural motif can always be placed within the selected asymmetric unit of the anti-Cheshire cell. The placement of structures according to this suggestion will ensure uniformity of presentation of all structurally equivalent Protein Data Bank models and will therefore diminish the possibility of confusing less crystallographically knowledgeable users of the PDB. The anti-Cheshire cells and their asymmetric units are defined and tabulated for all 65 space groups relevant to macromolecular crystallography that exhibit only rotational symmetry operations.
Toward an enantioselective synthesis of (-)-zampanolide: preparation of the C9-C20 region.

Progress toward the synthesis of the microtubule-stabilizing agent, (−)-zampanolide, is reported. Construction of the 2,6-cis-tetrahydropyran ring was accomplished utilizing ether transfer methodology in conjunction with an intramolecular radical cyclization reaction. Efficient installation of the C16–C20 side chain relied on a one-pot cross-metathesis/olefination sequence, Sharpless epoxidation, and selective reduction of a vinyl epoxide.
A stock market boom during a financial crisis

Abstract The surprising Argentine stock market boom during a financial crisis is explained as a result of investors using the stock market to circumvent cash withdrawal restrictions and capital controls and shift funds out of Argentina and into the United States.
Imaging chemical-bond formation with the scanning tunneling microscope: NH3 dissociation on Si(001).

We have directly observed chemisorption-induced changes in surface chemical bonding using a scanning tunneling microscope (STM). The dissociative adsorption of ${\mathrm{NH}}_{3}$ on Si(001) preserves the (2\ifmmode\times\else\texttimes\fi{}1) local symmetry, but STM images reveal changes in the spatial distribution of occupied electronic states which allow us to distinguish reacted and unreacted Si(001) dimers. The STM results on the reacted surface are interpreted in terms of tunneling through localized Si-H bonding orbitals of a Si(001)-(2\ifmmode\times\else\texttimes\fi{}1)H monohydride.
Natural history and patterns of recovery of contractile function in single left ventricle after Fontan operation.

BACKGROUND. Before the era of the Fontan procedure, the typical course of patients with single left ventricle (LV) consisted of heart failure and death during the second or third decade of life. Despite the advent of effective palliative therapy, ventricular dysfunction remains a significant clinical problem for these patients. METHODS AND RESULTS. To investigate the causes of ventricular dysfunction in these patients and to determine whether Fontan-type repair reverses deterioration of LV function, the ventricular dimensions, volume, shape, wall stress, and systolic function were determined by echocardiography in 84 patients 0.2-35 years old with double-inlet single LV or tricuspid atresia. Measurements were obtained in 67 patients after palliation (arterial shunt or pulmonary artery band) and in 47 patients a median of 4.4 years after a Glenn (n = 9) or a Fontan operation (n = 38). Before a Fontan procedure, ventricular volumes were 2 to 3 times normal. Ventricular afterload, assessed as circumferential and meridional end-systolic wall stress, became abnormal after 2 years of age. With age, LV shape changed progressively from ellipsoidal to spherical, as indicated by the decrease in long axis:short axis ratio from normal (1.9) toward unity. Concomitantly, the ratio of circumferential to meridional end-systolic wall stress fell from 1.3 to unity, the ratio of a sphere at equilibrium. This age-related change in shape and load occurred in concert with progressive deterioration of LV systolic function and contractility. Aortic oxygen saturation, an indicator of pulmonary blood flow and therefore volume work in single-ventricle physiology, was inversely and independently correlated with contractility. In the group of patients in whom a Glenn or a Fontan operation was performed at < 10 years of age, ventricular dimensions, volumes, and wall stress diminished and LV function and contractility improved after surgery (p < 0.001). In patients undergoing surgery after 10 years of age, few had improvement of LV function after surgery. Postoperative ventricular function and contractility were inversely related to age at surgery and to aortic oxygen saturation measured before surgery. CONCLUSIONS. Although Fontan-type repair of single ventricle early in life is associated with reversal of the abnormal contractile mechanics associated with age and volume load, this capacity for recovery diminishes with age at surgery.
The shared epitope and severity of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease that frequently leads to skeletal deformity and disability. A significant genetic contribution to the development of RA is widely accepted and estimated to account for approximately 60% of disease risk. 53 To date, the strongest genetic association has been reported with the human leukocyte antigen (HLA) region and, in particular, with HLA-DRB1 alleles that share a similar amino acid sequence. 37 The recognition of this common allele sequence, termed the shared epitope (SE), has provided insight into the genetics of this clinically diverse disease. Although the SE hypothesis was initially proposed to explain genetic susceptibility to RA, subsequent investigation suggests that the primary role of the SE may be in development of more severe disease manifestations. Numerous studies have pursued clarification of this relation; however, there is no definite consensus in the literature. Determination of the precise relationship between the SE and RA severity has profound implications for future patient care and research. The SE may provide prognostic information early in the course of disease for certain subgroups of RA patients or specific outcomes. Clinical trials may benefit with more precise results by identification and randomization of patients according to genetic characteristics. Clarification of the
Extraterrestrial Intelligence: An International Petition

The human species is now able to communicate with other civilizations in space, if such exist. Using current radioastronomical technology, it is possible for us to receive signals from civilizations no more advanced than we are over a distance of at least many thousands of light years. The cost of a systematic international research effort, using existing radio telescopes, is as low as a few million dollars per year for one or two decades. The program would be more than a million times more thorough than all previous searches, by all nations, put together. The results – whether positive or negative – would have profound implications for our view of our universe and ourselves. We believe such a coordinated search program is well justified on its scientific merits. It will also have important subsidiary benefits for radioastronomy in general. It is a scientific activity that seems likely to garner substantial public support. In addition, because of the growing problem of radiofrequency interference by civilian and military transmitters, the search program will become more difficult the longer we wait. This is the time to begin. It has been suggested that the apparent absence of a major reworking of the Galaxy by very advanced beings, or the apparent absence of extraterrestrial colonists in the solar system, demonstrates that there are no extraterrestrial intelligent beings anywhere. At the very least, this argument depends on a major extrapolation from the circumstances on Earth, here and now. The radio search, on the other hand, assumes nothing about other civilizations that has not transpired in ours. The undersigned* are scientists from a variety of disciplines and nations who have considered the problem of extraterrestrial intelligence – some of us for more than 20 years. We represent a wide variety of opinion on the abundance of extraterrestrials, on the ease of establishing contact, and on the validity of arguments of the sort summarized in the first sentence of the previous paragraph. But we are unanimous in our conviction that the only significant test of the existence of extraterrestrial intelligence is an experimental one. No a priori arguments on this subject can be compelling or should be used as a substitute for an observational program. We urge the organization of a coordinated, worldwide, and systematic search for extraterrestrial intelligence. Carl Sagan, Center for Radiophysics and Space Research, Cornell University, Ithaca, New York 14853
Evolution of jaw depression mechanics in aquatic vertebrates: insights from Chondrichthyes

Abstract The widely accepted phylogenetic position of Chondrichthyes as the sister group to all other living gnathostomes makes biomechanical analyses of this group of special significance for estimates of skull function in early jawed vertebrates. We review key findings of recent experimental research on the feeding mechanisms of living elasmobranchs with respect to our understanding of jaw depression mechanisms in gnathostome vertebrates. We introduce the possibility that the ancestral jaw depression mechanism in gnathostomes was mediated by the coracomandibularis muscle and that for hyoid depression by the coracohyoideus muscle, as in modern Chondrichthyes and possibly placoderms. This mechanism of jaw depression appears to have been replaced by the sternohyoideus (homologous to the coracohyoideus) coupling in Osteichthyes following the split of this lineage from Chondrichthyes. Concurrent with the replacement of the branchiomandibularis (homologous to the coracomandibularis) coupling by the sternohyoideus coupling as the dominant mechanism of jaw depression in Osteichthyes was the fusion and shift in attachment of the interhyoideus and intermandibularis muscles (producing the protractor hyoideus muscle, mistakenly refereed to as the geniohyoideus), which resulted in a more diversified role of the sternohyoideus coupling in Osteichthyes. The coracohyoideus coupling appears to have been already present in vertebrates where it functioned in hyoid depression, as in modern Chondrichthyes, before it acquired the additional role of jaw depression in Osteichthyes.
Deformation of an edge-cracked strip subjected to an arbitrary shear surface traction on the crack faces

Abstract The displacements and strains due to a shear surface traction acting on the faces of an edge crack in a strip are obtained by using Castigliano's theorem. It is shown that the displacement at a distance larger than the thickness of the strip from the crack becomes essentially a rigid body movement. The solutions obtained provide a basis for measurement of residual shear stress from observations of displacements or strains.
Observation of the Influence of Electron-Pair Spin Flips on Nuclear Thermal Relaxation

We report measurements on the thermal relaxation rate of water-of-hydration protons in magnetically dilute ${\mathrm{La}}_{2}$${\mathrm{Mg}}_{3}$${(\mathrm{N}{\mathrm{O}}_{3})}_{12}$\ifmmode\cdot\else\textperiodcentered\fi{}24${\mathrm{H}}_{2}$O:${\mathrm{Nd}}^{3+}$. The observed dependence of the proton relaxation rate on the angle between the applied magnetic field and the crystal symmetry axis exhibits a complicated structure which is shown to be consistent with that arising from processes in which a proton gives up its Zeeman energy to a pair of electrons, such that the Zeeman energy for the 3-spin system is conserved. These observations constitute direct evidence for the influence of electron-pair flips on proton thermal relaxation. Estimates made of the relative strength of such multiple-spin processes are shown to correspond to observed data.
Everywhere in Life There Are Numbers: Questions for Social Justice Educators in Mathematics and Everywhere Else

This essay looks at reflective questions most teachers struggle with. These self-analytic questions are framed by two books in particular, Eric Gutstein's Reading and Writing the World with Mathema...
Changes in latency and form of the photically induced average evoked response in human infants.

Abstract The occipital average evoked response to randomly presented photic flashes was computed by analog to digital conversion and programming designed to ensure elimination of artifact. Electroencephalographic studies were made of 49 normal newborn babies, of whom 35 were followed serially up to 6 months of age. Developmental changes in form and latency of the main positive and negative peaks are described for individual subjects and for the group. The relatively simple newborn evoked response becomes more complex as new components appear, achieving, at approximately 2 months, a form resembling the adult response but with longer latency values.
Dealing with Fear and Anxiety in the School Setting: Behavioral Approaches to Treatment.

This review focuses on behavioral intervention strategies for the reduction of school-related fears and anxieties. Four major behavior therapy procedures are reviewed: systematic desensitization and the variations of this procedure, modeling approaches, and self-control and cognitive behavioral approaches. General trends in school-related fears and anxiety reduction research are also discussed.
Formation of metastable and equilibrium phases during mechanical alloying of Al and Mg powders

Formation of metastable and equilibrium phases during mechanical alloying by high-energy ball milling of mixtures of Al and Mg powders was studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). Different phases were formed, depending on the overall composition of the starting mixture. A powder mixture of nominal composition 40 at. pct Mg gradually becomes converted into a metastable supersaturated Al(Mg) face-centered cubic (fcc) solid solution having approximately 23 at. pct Mg in solution. Powder mixtures of nominal composition of 60 or 80 at. pct Mg gradually transform into the equilibrium γ phase during mechanical alloying, but for the composition of 80 at. pct Mg, some unalloyed Mg is left. Mechanical alloying is comparable to rapid solidification in producing metastable phases in the Al-Mg system, except that mechanical alloying is likely to leave some residual unalloyed elements. There is no indication of the formation of the other equilibrium phase, the β phase, present in the phase diagram. The reason why the β phase does not form is thought to be related to the complex structure and a very large unit cell associated with this phase. However, the β phase is obtained if the mechanical alloyed powders are heat-treated at higher temperatures.
Transdermal delivery of 5-fluorouracil (5-FU) by 1-alkylcarbonyl-5-FU prodrugs

The members of a series of 1-alkylcarbonyl-5-FU prodrug derivatives have been characterized and evaluated for their abilities to deliver 5-FU into and through skin. There was no correlation of lipid solubility or partition coefficient with relative abilities of the members of the 1-alkylcarbonyl series to deliver 5-FU through skin. However, there was a correlation with water solubility within the series. Although their lipid solubilities and partition coefficient values were greater than those of the 1-alkyloxycarbonyl series, only 1-acetyl-5-FU was more soluble in water, and only 1-acetyl-5-FU delivered more total 5-FU species through the skin than the corresponding member of the 1-alkyloxycarbonyl series. On the other hand, the 1-alkylcarbonyl series was more effective at enhancing the ratio of dermal to transdermal delivery (D/T delivery ratio) than the 1-alkyloxycarbonyl series, presumably because of the rapid hydrolysis of the members of the former series once contact with the aqueous domains of the epidermis had been made. Thus, the hypothesis that enhanced D/T delivery ratio requires rapid hydrolysis of the prodrug after it partitions into the skin is supported. Although the prodrugs hydrolyzed rapidly in water, they were stable in isopropyl myristate (IPM) during their application in IPM to highly hydrated skin. There was also a good correlation of calculated solubility parameters for the prodrugs with their permeability coefficients.
Direct selection of mutations in the human mitochondrial tRNAThr gene: reversion of an 'uncloneable' phenotype.

Abstract Several regions of the human mitochondrial genome are refractory to cloning in plasmid and bacteriophage DNA vectors. For example, recovery of recombinant M13 clones containing a 462 basepair MboI-Kpn I restriction fragment that spans nucleotide positions 15591 to 16053 of HeLa cell mitochondrial DNA was as much as 100-fold lower than the recovery of M13 clones containing other regions of the human mitochondrial genome. All of 50 recombinant M13 clones containing this ‘uncloneable’ fragment had one or more changes in nucleotide sequence. Each clone contained at least one alteration in two nucleotide positions within the tRNAThr gene that encode portions of the anticodon loop and D-stem of the HeLa mitochondrial tRNAThr. These results imply that the HeLa mitochondrial tRNAThr gene is responsible for the ‘uncloneable’ phenotype of this region of human mitochondrial (mt) DNA. A total of 61 nucleotide sequence alterations were identified in 50 independent clones containing the HeLa mt tRNAThr gene. 56 mutations were single-base substitutions; 5 were deletions. Approximately 80% of the base substitution mutations were A:T → C:C transitions. A preference for A:T → G:C transition mutations also characterizes polymorphic base substitution variants in the mitochondrial DNA of unrelated individuals. This similarity suggests that human mitochondrial DNA sequence variation within and between individuals may have a common origin.
Determination of PCBs in Fish Using Enzyme‐linked Immunosorbent Assay (ELISA)

: Polychlorinated biphenyls (PCBs) were determined in fish tissue using an enzyme-linked immunosorbent assay (ELISA). Standard curves for Aroclor 1248, 1254, and 1260 in catfish tissue were developed with ranges from 0.05 to 0.5 ppm and 0.5 to 5.0 ppm. Wild fish were initially analyzed using gas chromatography/electron-capture detection (GC/ECD) and those having residues within the standard curve ranges were analyzed with ELISA. Results obtained using ELISA and GC/ECD were not significantly different (p < 0.05) from 0.05 to 0.5 ppm. From 0.5 to 5.0 ppm, the standard curve for Aroclor 1254 was the best predictor of total PCB in wild fish samples.
Sulfate-Reducing Bacteria and Pyritic Sediments in Antarctica

Black lacustrine and marine sediments occur in the McMurdo Sound region of Antarctica. The black color is due to the presence of iron sulfide, precipitated by sulfate-reducing bacteria (Desulfovibrio) in the presence of decaying organic matter of algal origin. Viability of sulfate-reducing bacteria in the sediments was demonstrated in the laboratory by culturing in anaerobic liquid media. It is probable that sulfate-reducing bacteria are widely distributed in Antarctica.
Encouraging Pollution‐Free Energy: The Diffusion of State Net Metering Policies*

Objective. As the price of energy swells, renewable energy sources will serve as important alternatives to fossil fuels. Identifying what influences a state to adopt a policy that promotes the construction of renewable energy sources is an important step toward understanding the nature of our future energy supplies. Methods. Using an event-history analysis, we examine three competing diffusion explanations on the likelihood of a state adopting net metering. Results. We find that regional policy diffusion influences the likelihood of a state to adopt a net metering policy. Conclusions. The results suggest that states are learning from one another and that the EPA's regional offices help facilitate this diffusion.
Nonlinear Surface Plasmon Polaritons

We present analytical analyses of the nonlinear interaction of SPP fields at a silver-vacuum interface, in the presence of a third order optical susceptibility in the metal. Both sum- and difference-frequency generation interactions are addressed.
“I CAN DO IT MYSELF:” TRAINING THE SERVICE CONSUMER TO CONTRIBUTE TO SERVICE PRODUCTIVITY

Scene I: A major hotel. 1. Guest A called the desk right after check‐in to report a burned‐out light bulb and an absence of hot water; both were fixed in an hour. Guest A also slept better, as the hotel assigned him a quiet room when he identified himself as a light sleeper. Guest B did not communicate to management until check‐out time, when he complained that there was no hot water and he had to read in the dark; he was overheard by new guests checking in, who asked if the hotel was undergoing a disaster.
Effective Rainfall in Poorly Drained Microirrigated Citrus Orchards

Effective rainfall (ER) is the portion of total rainfall that plants use to help meet their consumptive water requirements, and is an important component of water resource budgeting for irrigation. The USDA's Technical Release no. 21 (TR-21) is used to predict ER and irrigation requirements for south Florida citrus, but its accuracy is in question due to high-intensity rainfall, poorly drained soils, and partial irrigation coverage in microirrigated orchards. We evaluated the calculation of ER by TR-21 under these conditions by monitoring rainfall, irrigation, water table depth, evapotranspiration (ET), and soil water content inside and outside of the microirrigation-wetted pattern in four orchards for a total of 83 site-months. We developed a soil water budget to calculate daily water table upflux, root zone water content, water used, and ER separately for the irrigated and nonirrigated root zones. Water budget ER calculated by site ranged between -3.3% and +18.2% of TR-21 ER, with a mean of +10%. A linear correlation between water budget ER and TR-21 ER using pooled data from all four sites yielded the equation: Water Budget ER (mm) = 0.79 [TR-21 ER (mm)] + 17.7, r = 0.84. A hypothetical ER comparison using 30-yr mean rainfall and ET data showed that annual ER calculated by TR-21 amounted to 673 mm, while water budget ER totaled 744 mm, or +10.5%. We suggest that the TR-21 method has the level of accuracy needed to allocate water for microirrigated citrus on poorly drained south Florida soils.
An empirical model for predicting diurnal air-temperature gradients from edge into old-growth Douglas-fir forest

Abstract Edge — the boundary line between clearcut and adjacent old-growth forest — is one of the critical landscape elements in the highly fragmented forest landscapes of North America's Pacific Northwest. Ecological phenomena at edges may be better understood by examining the physical environments near the edge. To further this objective diurnal air temperature gradients were measured along 16 gradients from the edge into the interior old-growth Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] forest over the 1989 and 1990 growing seasons and analyzed effects of edge orientation (relation of edge-facing to the azimuth) and macroclimate (local weather conditions of the clearcut) on these gradients were also explored through regression analysis. The air temperature gradient was expressed with a simple exponential equation involving three intermediate variables of interest: air temperature in the interior forest (TEMPIF), difference in air temperature between the edge and inside the forest (Δ AT), and changing ratio of temperature along the gradient (SLOPE). Linear or nonlinear regression equations were developed to predict TEMPIF, Δ AT, and SLOPE. Correlation analysis always preceded regression analysis, in which the relationships between the regression parameters and independent variables representing edge orientation and macroclimate were further explored. A computer model developed from the final empirical relationships successfully predicted air temperature gradients, circumventing the need for time-consuming field measurements with expensive meteorological instruments, and generated new information about the influences of edge orientation and macroclimate on air temperatures. TEMPIF, ΔAT, and SLOPE were shown to be highly sensitive to the dependent variables. Although model application should be limited to edges created by recent (10- to 15-year-old) clearcuts adjoining old-growth Douglas-fir forest, the modeling approach could be applied to edges with different characteristics by modifying the relationships.
An approximation approach to the identification of nonlinear systems based on frequency-response measurements†

We present a method for determining a model of the form SM from measurements on the steady-state response of a non-linear system to co-sinusoidal inputs at a number of amplitudes and frequencies. In earlier papers the parameter identifiability of the SM structure for this type of input/output experiment was established using an interpolation approach. Here we use a harmonic analysis technique to choose linear subsystems in the model and then minimization of an integral square-error criterion to select certain free coefficients within these subsystems. The results are illustrated by application to a forced Duffing equation and a forced Van der Pol equation.
Tracking of planetary terrains

The AFAST project (Autonomously Feature And Star Tracking) at the Jet Propulsion Laboratory, California Institute of Technology is engaged in the attitude determination and tracking of the CCD camera pointing direction on future spacecraft missions. Ground based attitude determination is time-consuming and costly. This implies that the attitude determination and the tracking of the pointing direction must be autonomous and rely exclusively on the CCD sensor. Also, distant observations call for autonomy, as relay times to Earth make ground control infeasible. This paper presents a strategy to track the pointing direction on planetary terrains. The strategy utilizes multiple closed contours in a planetary image. It accomplishes tracking by recognizing a constellation of the closed contours. The strategy is adaptable to both spacecraft and missile applications. >
SUBGEN: a genetic approach for subcircuit extraction

The problem of finding subcircuits in a larger circuit arises in many contexts in computer-aided design. In this paper, we present an approach to model the subcircuit extraction problem using genetic representation and control and propose a genetic algorithm. The genetic algorithm called SUBGEN, can be applied to identify subcircuits in a large circuit graph and is independent of circuit and technology factors. Results are presented based on applying the proposed algorithm to select CMOS circuits.
Are there laws of genome evolution

Research in quantitative evolutionary genomics and systems biology led to the discovery of several universal regularities connecting genomic and molecular phenomic variables. These universals include the log-normal distribution of the evolutionary rates of orthologous genes; the power law–like distributions of paralogous family size and node degree in various biological networks; the negative correlation between a gene's sequence evolution rate and expression level; and differential scaling of functional classes of genes with genome size. The universals of genome evolution can be accounted for by simple mathematical models similar to those used in statistical physics, such as the birth-death-innovation model. These models do not explicitly incorporate selection; therefore, the observed universal regularities do not appear to be shaped by selection but rather are emergent properties of gene ensembles. Although a complete physical theory of evolutionary biology is inconceivable, the universals of genome evolution might qualify as “laws of evolutionary genomics” in the same sense “law” is understood in modern physics.
Association of Sire Dystocia Transmitting Ability with Progeny Linear Type Traits in Holsteins

Data on 13 traits of 11,260 progeny of 775 sires in the Carnation Genetics linear type appraisal program were analyzed to determine the association between sire dystocia transmitting ability and progeny linear type traits. Mean linear type scores ranged from 25.0 to 29.8 on a scale of 1 to 50. Parity, stage of lactation, and interactions of evaluator by parity and evaluator by stage were sources of variation for most traits. First quartile (easy) and fourth quartile (most difficult) sires grouped by dystocia transmitting ability differed in daughter linear type scores for stature, dairy character, rump angle, center ligament, udder depth, teat length, teat placement, and rump width. Differential use of easy calving bulls on heifers might result in progeny with lower type scores for stature, dairy character, rump angle, legs, and rump width. Average type scores differed by less than 1 unit for all traits, indicating little correlated response in linear type traits through use of bulls whose progeny are born with least difficulty.