cssi/SciSciGPT-SciSciNet huggingface dataset:
An approach through the looking-glass

Forty food-deprived cockerel chicks were tested individually in a straight runway containing a familiar food cup that moved when the chicks moved. The food cup always moved in the same direction as the chick: For 20 experimental chicks it moved twice as far as the chick; for 20 control chicks it moved half as far. In Lewis Carroll’s (1898/1926) picturesque terminology, the experimental chicks were tested in Alice’s “room through the looking-glass,” in which, in order to approach the food cup, they had to “walk the other way.” Although the control chicks performed well, the experimental chicks evinced the runway behavior that characterizes positive feedback: They persistently chased the food cup away. This means that the spatial polarity of visual feedback is critical and implies that an ordinary approach response is but an automatic (closed-loop) realization of an intended visual perception.
Comparison of in situ dynamic moduli and laboratory moduli of Mesaverde rocks

Abstract Mechanical and sonic tests were performed on sandstones and shales from four gas wells in the Mesaverde formation. A previous publication showed a comparison of the static and dynamic laboratory moduli. This paper describes how field velocity logs were used to derive field dynamic moduli, and it shows the 3-way comparison which was then performed for these stiffness properties. The results show no agreement between the three sets of values; differences between dynamic stiffness coefficients from the field and the laboratory exceed 200%; differences between static and dynamic coefficients range up to 600%. In turn, this indicates that a reliable method of estimating mechanical rock properties for hydraulic fracturing design has not been established, and that such a task should be pursued.
Acute myeloid leukemia associated with hemophagocytic syndrome and t(4;7)(q21;q36)

Hemophagocytic syndrome (HS) is a histiocytic reactive process often associated with infections and/or malignancies. Clonal karyotypic abnormalities have been the hallmark of several hematological malignancies and have been shown to be of clinical significance in terms of both diagnosis and prognosis. While there are limited reports of both clonal and nonclonal abnormalities in HS, their clinical significance has not been established. Detection of such clonal abnormalities, as seen in some cases of HS, may indicate the presence of an occult malignant process, even when there is no microscopic evidence of a hematological malignancy. We report a case of HS in a child with clonal t(4;7)(q21;q36) which later progressed to acute myeloid leukemia (AML) with further clonal evolution. Our case strengthens the argument that cytogenetic studies in HS may be important in identifying the underlying occult malignant process.
Asymptotic analysis of PTT type closures for network models with variable junction concentrations

In this paper we explore variations on the PTT closure for transient network models. These models are compared for the case of a steady shear flow using asymptotic analysis for large shear rates and using numerical solutions for all shear rates. The results show that including the changing number of junctions in the closure is necessary to reproduce the behavior of the full model.
Performance potentials of an optical bus using wavelength-division multiplexing

Optical fiber busses supporting multiple concurrently usable channels through the use of wavelength division multiplexing can meet the demanding interconnection requirements of high performance multiprocessors. Using a simple analytical model, we establish why global channel access protocols for the WDM channels are inadequate for a WDM optical fiber bus. We propose a simple WDM bus that supports a small number of channels and uses readily available receivers and transmitters with fixed tunings. A simple channel allocation and arbitration strategy allows up to 100 processors to be connected using a single WDM bus with only 5 WDM channels. Simulated performance shows that the bus does not become a bottleneck even when 100 processors are connected. The WDM channels also allow cache coherence and processor synchronization to be easily supported, making the bus feature- compatible with the IEEE Futurebus+ and SCI standards.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Pressure Surges Following Sudden Air Pocket Entrapment in Storm-Water Tunnels

AbstractDeep storm-water storage tunnels may undergo pressurization during intense rain events. In the process, air pockets may become entrapped and pressurized, causing significant flow changes. Currently, the role of nearby surge relief structures is uncertain with respect to air-water interactions. This paper presents results from experimental and numerical investigations on air pocket entrapment and compression following reflection of inflow fronts on system boundaries. Steady flows were established in the pipe apparatus, with the upstream portion flowing in the pressurized regime while the downstream flowed in free surface conditions. Sudden flow obstruction caused by valve maneuvering at the downstream end generated unsteady conditions that were monitored by transducers and a MicroADV probe. Partial valve maneuver runs were performed, aiming to represent cases in which surge relief is provided during air pocket compression/expansion cycles. Whereas experiments performed without surge relief (complet...
Two new theorems in heat conduction.

Heat conduction theorems, discussing steady state system /geometry, conductivities and source strengths/
The domestic political logic of Gorbachev's new thinking in foreign policy

In a chapter, in Myths of Empire (1991), I argued that Gorbachev was seeking to transform atavistic ideas and institutions that had been functional for the initial stage of building socialism, but had become fetters on production and a danger to Soviet security. New concepts of international relations were needed to reduce the dangers and costs of the old confrontational mindset, and also to justify a shift in domestic arrangements away from the military industrial complex, central planning and obsessive secrecy. Together with the international contextual factors that helped to set this process in motion, this domestic political dynamic explains both the peaceful end of the cold war and also the collapse of the Soviet system, which was an unintended byproduct of the democratizing tactics that Gorbachev used to overcome resistance from the old-school military-industrial and ideological elites. These arguments are generally supported by recent accounts of the Soviet collapse and the end of the cold war.
Perinatal stroke in children with motor impairment: a population-based study.

Author(s): Wu, Y W; March, W M; Croen, L A; Grether, J K; Escobar, G J; Newman, T B | Abstract: Objective. Risk factors for perinatal arterial stroke (PAS) are poorly understood. Most previous studies lack an appropriate control group and include only infants with symptoms in the newborn period. We set out to determine prenatal and perinatal risk factors for PAS. Methods. In a population-based, case-control study nested within the cohort of 231582 singleton infants who were born at greater than or equal to36 weeks' gestation in Northern California Kaiser hospitals from 1991 to 1998, we searched electronically for children with motor impairment and reviewed their medical records to identify diagnoses of PAS. Control subjects were randomly selected from the study population. A medical record abstractor reviewed delivery records without knowledge of case status. Results. The prevalence of PAS with motor impairment was 17/100000 live births. Of 38 cases, 26 (68%) presented after 3 months of age with hemiparesis or seizures. All 12 newborns with acute stroke symptoms had seizures. A delayed presentation was more common in children with moderate to severe motor impairment than among infants with only mild motor abnormalities (24 of 31 vs 2 of 7). Prepartum risk factors significantly associated with PAS in multivariate analysis were pre-eclampsia (odds ratio [OR]: 3.6; 95% confidence interval [CI]: 1.1-11.4) and intrauterine growth restriction (OR: 5.3; 95% CI: 1.5-18.6). Newborns with PAS were also at higher risk of delivery complications, such as emergency cesarean section (OR: 6.8; 95% CI: 2.7-16.6), 5-minute Apgar l7 (OR: 23.6; 95% CI: 4.1-237), and resuscitation at birth (OR: 4.5; 95% CI: 1.6-12.3). Conclusions. Preeclampsia and intrauterine growth restriction ( IUGR) may be independent risk factors for perinatal stroke resulting in motor impairment. Large multicenter studies that include all children with perinatal stroke are needed to determine further the risk factors and outcome of perinatal stroke.
Binding of hyaluronic acid to mammalian fibrinogens.

We have postulated that the interaction of hyaluronic acid (HA), an extracellular matrix glycosaminoglycan with fibrin is important during the early stages of wound healing and inflammation (J. Theor. Biol. 119:219; 1986), and have demonstrated the specific binding of 125I-labeled HA to human fibrinogen (J. Biol. Chem. 261:12 586; 1986). To determine whether HA binding is limited to human fibrinogen, we tested the ability of fibrinogens from various mammalian species to bind 125I-HA using a dot-blot assay. Increasing amounts of fibrinogen were adsorbed to nitrocellulose, and incubated with 125I-HA in the presence or absence of a 100-fold excess of nonradiolabeled HA to assess specific binding. In three dependent experiments, the amount of 125I-HA bound/mg fibrinogen was determined from the slope derived by linear regression analysis of specifically bound 125I-HA versus protein concentration. A Student's t-test was performed to determine whether the slopes were statistically greater than zero. HA binding was considered statistically significant when P<0.05 was obtained by this analysis. Rabbit and dog fibrinogens significantly bound HA in all three trials. Baboon fibrinogen demonstrated significant HA binding in two of three trials. Pig, sheep and goat fribrinogens bound HA significantly in only one of three trials, whereas horse, rat and cow fibrinogens did not bind HA significantly at all. We conclude that fibrinogen from mammalian species other than human can specifically bind HA. The ability of fibrinogen to bind HA appears to correlate with an evolutionary divergence that separated human, baboon, dog, rabbit and rat from cow, pig, horse, goat and sheep.
High-density plasma etching of aluminum copper on titanium tungsten

A multi-step high density plasma etch process, based on chlorine and sulfur hexafluoride chemistry ( SF6 ), for LRC single wafer metal etcher was developed, characterized and optimized to anisotropically etch the metal stack which consists of a thin titanium tungsten ARC, hot deposited aluminum copper over titanium tungsten. The titanium tungsten used in the metal structure presents unique constraints on etch selectivity to underlying film while simultaneously requiring clearing metal stringers. The etching was further complicated by lateral etching of aluminum copper ( AlCu ) during titanium tungsten ( TiW ) etch and overetch steps. With the help of design-of-experiment techniques, multi-variable factorial experiments were conducted to determine the optimum processes for the bulk metal etch, barrier metal layer etch and overetch steps. Characterization parameters include the metal etch rate, etch selectivity, CD line-width, metal resistance and plasma charging damages. Special attention was paid to the overetch window since the metal quality is very sensitive to the overetch conditions. Insufficient overetch may leave metal stingers or metal shorts. Excessive overetch may cause severe CD undercutting and great loss of TEOS oxide under-layer.
Morphological Control of Zirconia Nanoparticles through Combustion Aerosol Synthesis

Ceramic oxide nanoparticles produced by flame-based processes are typically agglomerated, which can limit their use in some applications. In this paper, a novel combustion synthesis method that utilizes the spraying of combustible droplets into a premixed flame to produce nanoscale crystalline particles of agglomerated and unagglomerated morphologies is described. Although the same flame-based experimental setup is used in both cases, variation in peak flame temperatures results in a corresponding variation between fractallike agglomerates and single isolated spherical particles. TEM/ED analysis shows that both classes of particles are the tetragonal crystal phase of zirconia. In the case of the unagglomerated spherical particles, results indicate that each precursor solution droplet, which acts as the feed, produces multiple spherical ceramic nanoparticles with a number mean diameter of 90 nm. The use of an inertial impaction stage in the precursor feed line to eliminate large feed droplets leads to a decrease in the number mean diameter to 60 nm, suggesting that crystalline spherical nanoparticles can be produced in a continuous flame-based process through control of the feed droplet size.
Propositional encodings are a subset of organization theory

The notion that human associative learning is a usually conscious, higher-order process is one of the tenets of organization theory, developed over the past century. Propositional/sequential encoding is one of the possible types of organizational structures, but learning may also involve other structures.
The Riddle of Laughter Neural and Psychoevolutionary Underpinnings of Joy

Modest advances are being made in understanding the neurology and functions of laughter. The discovery of tickle-induced “laughter” in animals should facilitate the characterization of this basic emotional response of the mammalian brain. The existence of such vocal activities in species other than humans (e.g., rats) suggests that the fundamental brain processes for joyful affect may have emerged early in vertebrate brain evolution. Here, I summarize the little that we know about the evolutionary and brain sources of laughter, and how the accompanying positive emotions may solidify social bonds within the mammalian brain. Discovery of unique neurochemistries that specifically promote laughter and joy may provide clues for development of new classes of antidepressants.
Multivariate Weibull Distribution: Theory

The univariate Weibull distribution is frequently used in accelerated life testing and failure time models. It reduces to the exponential distribution when the shape parameter is equal to one. Multivariate Weibull distributions encompass distributions exhibiting Weibull characteristics and relate to multivariate exponential distributions of various types. Applications include reliability analysis, survival analysis, and repeated failure time analysis. Keywords: multivariate exponential distribution; survival analysis; reliability function; hazard rate; gamma distribution; failure time
Design and implementation of key proposed MPI-3 one-sided communication semantics on infiniband

As part of the MPI-3 effort, Remote Memory Access (RMA) working group has proposed several extensions to the one-sided communication interface. These extensions promise to address several of its existing limitations. However, their performance advantages need to be clearly highlighted for widespread acceptance of the new interface. In this paper, we present design and implementation of some of the key one-sided semantics proposed for MPI-3 over InfiniBand, using the MVAPICH2 library. Our evaluation shows that the newly proposed Flush semantics allow for more efficient handling of completions and the requestbased operations can help achieve close to optimal overlap in a Get-Compute-Put model.
Progress in Ichnology--Study of Animal Spoor: ABSTRACT

Trace fossils--the tracks, trails, burrows, borings, and other spoor made by ancient organisms--are difficult to identify and classify phylogenetically but can be assigned relatively easily to various taxonomical, behavioral, and preservational categories. Analyses of these aspects of spoor can yield considerable information that is potentially very useful in geology. The most significant contribution of spoor to date has been in paleoecology and environmental reconstructions, including recognition of local and regional-temporal facies changes and documentation of individual paleoecologic parameters. Spoor are potentially valuable indicators of bathymetry, currents, food supplies, aeration, rate of deposition, depositional history, and substrate stability; they also may be useful to some extent in establishing ancient temperature and salinity regimes. The chief contribution of spoor to paleontology is partial resolution of "the problem of the incomplete fossil record." This includes, inasmuch as possible, the identity, behavioral patterns, and certain evolutionary trends among ancient organisms not otherwise represented in the fossil record. Reconstruction of diversity and trophic relations is important and generally feasible. Trace-making animals are important sedimentologically because they destroy previous sedimentary structures and fabrics and produce new structures and fabrics. Spoor have certain potential even in biostratigraphy and local correlations. Many trace fossils are excellent geopetals. Ichnology--the study of spoor--has developed slowly relative to other branches of geology, but the subdiscipline is now on the threshold of widespread acceptance and considerably increased application. End_of_Article - Last_Page 339------------
The Rise of China: Implications for Latin American Development

This article analyses the implications of the rapid economic rise of China for the development prospects of Latin America. Based on an analysis of the changing trade relations between China and 15 Latin American countries over the period 2000–6, it argues that these relations have significantly exacerbated the subcontinent's dilemma of being caught in the middle-income trap. At the same time, some of the key drivers behind China's economic success point to a possible solution, first and foremost the lessons provided by its proactive development strategy which has focused on developing domestic technological capabilities and diversifying the productive structure with a move up the value chain.
Dipolar cortico-muscular electrical stimulation: a novel method that enhances motor function in both - normal and spinal cord injured mice

Background Electrical stimulation of the central and peripheral nervous systems is a common tool that is used to improve functional recovery after neuronal injury.
Prognostic significance of electrical alternans versus signal averaged electrocardiography in predicting the outcome of electrophysiological testing and arrhythmia-free survival

OBJECTIVE: To investigate the accuracy of signal averaged electrocardiography (SAECG) and measurement of microvolt level T wave alternans as predictors of susceptibility to ventricular arrhythmias. DESIGN: Analysis of new data from a previously published prospective investigation. SETTING: Electrophysiology laboratory of a major referral hospital. PATIENTS AND INTERVENTIONS: 43 patients, not on class I or class III antiarrhythmic drug treatment, undergoing invasive electrophysiological testing had SAECG and T wave alternans measurements. The SAECG was considered positive in the presence of one (SAECG-I) or two (SAECG-II) of three standard criteria. T wave alternans was considered positive if the alternans ratio exceeded 3.0. MAIN OUTCOME MEASURES: Inducibility of sustained ventricular tachycardia or fibrillation during electrophysiological testing, and 20 month arrhythmia-free survival. RESULTS: The accuracy of T wave alternans in predicting the outcome of electrophysiological testing was 84% (p < 0.0001). Neither SAECG-I (accuracy 60%; p < 0.29) nor SAECG-II (accuracy 71%; p < 0.10) was a statistically significant predictor of electrophysiological testing. SAECG, T wave alternans, electrophysiological testing, and follow up data were available in 36 patients while not on class I or III antiarrhythmic agents. The accuracy of T wave alternans in predicting the outcome of arrhythmia-free survival was 86% (p < 0.030). Neither SAECG-I (accuracy 65%; p < 0.21) nor SAECG-II (accuracy 71%; p < 0.48) was a statistically significant predictor of arrhythmia-free survival. CONCLUSIONS: T wave alternans was a highly significant predictor of the outcome of electrophysiological testing and arrhythmia-free survival, while SAECG was not a statistically significant predictor. Although these results need to be confirmed in prospective clinical studies, they suggest that T wave alternans may serve as a non-invasive probe for screening high risk populations for malignant ventricular arrhythmias.
Metabolomics-Lipidomics of Eicosanoids and Docosanoids Generated By Phagocytes

Lipid mediators derived from essential fatty acids, such as arachidonic acid, play important roles in physiologic and pathophysiologic processes. Prostaglandins, thromboxane, and leukotrienes are well-known eicosanoids that play critical roles in hemodynamics and inflammation. New families of mediators were recently uncovered that constitute a new genus stimulating resolution of acute inflammation, and are organ-protective. These include the resolvins (E-series and D-series), protectins (neuroprotectin D1/protectin D1), and maresins biosynthesized from omega-3 essential fatty acids. Phagocytes play major roles in tissue homeostasis and have a high capacity to produce these mediators, which depend on their tissue and state of activation. It is important to select appropriate methods for identifying target mediators and pathway biomarkers. In this unit, we review state-of-the-art approaches to identify and profile eicosanoid and docosanoid pathways, including specialized pro-resolving mediators resolvins, protectins, and maresins, in relation to their biosynthesis and inactivation by neutrophils and macrophages.
Gene expression profiling of experimental traumatic spinal cord injury as a function of distance from impact site and injury severity.

Changes in gene expression contribute to pathophysiological alterations following spinal cord injury (SCI). We examined gene expression over time (4 h, 24 h, 7 days) at the impact site, as well as ...
Lygus hesperus feeding and salivary gland extracts induce volatile emissions in plants.

Induction of plant volatiles by leaf-chewing caterpillars is well documented. However, there is much less information about volatile induction by insects with different feeding habits. We studied the induction of plant volatiles by a piercing–sucking insect, the western tarnished plant bug Lygus hesperus Knight. Adults of both genders and nymphs of Lygus induced the local emission of a blend of volatiles from both cotton and maize. Feeding by Lygus also induced the systemic emission of volatiles that was similar but less complex than the blend emitted at the site of feeding. Infestation by mated, mature adult females (>4 days old), but not by nymphs or mature males, caused detectable emission of α-pinene, myrcene, and (E)-β-caryophyllene, compounds that are stored in the glands of cotton tissue. This indicated that damage to glands in the petiole and leaf by the female ovipositor, rather than feeding, contributed significantly to the emission of these volatiles. Girdling the plant stem to disrupt phloem transport markedly decreased the movement of 14C-labeled photosynthetic products to the apex of the plant, and this treatment also markedly reduced the amount of systemically induced volatiles caused by Lygus feeding. Lygus salivary gland extracts were capable of inducing emission of the same volatile blend as measured for plants infested by feeding insects or treated with volicitin, an elicitor isolated from caterpillar regurgitant. The results indicate that L. hesperus is capable of inducing the emission of plant volatiles and that induction is caused by an elicitor that is contained in the insect salivary gland.
Comparison of rotator cuff muscle architecture between humans and other selected vertebrate species

In this study, we compare rotator cuff muscle architecture of typically used animal models with that of humans and quantify the scaling relationships of these muscles across mammals. The four muscles that correspond to the human rotator cuff – supraspinatus, infraspinatus, subscapularis and teres minor – of 10 commonly studied animals were excised and subjected to a series of comparative measurements. When body mass among animals was regressed against physiological cross-sectional area, muscle mass and normalized fiber length, the confidence intervals suggested geometric scaling but did not exclude other scaling relationships. Based on the architectural difference index (ADI), a combined measure of fiber length-to-moment arm ratio, fiber length-to-muscle length ratio and the fraction of the total rotator cuff physiological cross-sectional area contributed by each muscle, chimpanzees were found to be the most similar to humans (ADI=2.15), followed closely by capuchins (ADI=2.16). Interestingly, of the eight non-primates studied, smaller mammals such as mice, rats and dogs were more similar to humans in architectural parameters compared with larger mammals such as sheep, pigs or cows. The force production versus velocity trade-off (indicated by fiber length-to-moment arm ratio) and the excursion ability (indicated by fiber length-to-muscle length ratio) of humans were also most similar to those of primates, followed by the small mammals. Overall, primates provide the best architectural representation of human muscle architecture. However, based on the muscle architectural parameters of non-primates, smaller rather than larger mammals may be better models for studying muscles related to the human rotator cuff.
The design and implementation of a new surveillance system for venous thromboembolism using combined active and passive methods

Estimates of venous thromboembolism (VTE) incidence in the United States are limited by lack of a national surveillance system. We implemented a population-based surveillance system in Oklahoma County, OK, for April 1, 2012 to March 31, 2014, to estimate the incidences of first-time and recurrent VTE events, VTE-related mortality, and the proportion of case patients with provoked versus unprovoked VTE. The Commissioner of Health made VTE a reportable condition and delegated surveillance-related responsibilities to the University of Oklahoma, College of Public Health. The surveillance system included active and passive methods. Active surveillance involved reviewing imaging studies (such as chest computed tomography and compression ultrasounds) from all inpatient and outpatient facilities. Interrater agreement between surveillance officers collecting data was assessed using κ. Passive surveillance used International Classification of Disease , Ninth Revision ( ICD-9 ) codes from hospital discharge data to identify cases. The sensitivity and specificity of various ICD-9 –based case definitions will be assessed by comparison with cases identified through active surveillance. As of February 1, 2015, we screened 54,494 (99.5%) of the imaging studies and identified 2,725 case patients, of which 91.6% were from inpatient facilities, and 8.4% were from outpatient facilities. Agreement between surveillance officers was high (κ ≥0.61 for 93.2% of variables). Agreement for the diagnosis of pulmonary embolism and diagnosis of deep vein thrombosis was κ = 0.92 (95% CI 0.74-1.00) and κ = 0.89 (95% CI 0.71-1.00), respectively. This surveillance system will provide data on the accuracy of ICD-9 –based case definitions for surveillance of VTE events and help the Centers for Disease Control and Prevention develop a national VTE surveillance system.
An improved phylogeny of the Andean tit-tyrants (Aves, Tyrannidae): More characters trump sophisticated analyses

Abstract The phylogeny of the flycatcher genus Anairetes was previously inferred using short fragments of mitochondrial DNA and parsimony and distance-based methods. The resulting topology spurred taxonomic revision and influenced understanding of Andean biogeography. More than a decade later, we revisit the phylogeny of Anairetes tit-tyrants using more mtDNA characters, seven unlinked loci (three mitochondrial genes, six nuclear loci), more closely related outgroup taxa, partitioned Bayesian analyses, and two coalescent species-tree approaches (Bayesian estimation of species trees, BEST; Bayesian evolutionary analysis by sampling trees, *BEAST). Of these improvements in data and analyses, the fourfold increase in mtDNA characters was both necessary and sufficient to incur a major shift in the topology and near-complete resolution. The species-tree analyses, while theoretically preferable to concatenation or single gene approaches, yielded topologies that were compatible with mtDNA but with weaker statistical resolution at nodes. The previous results that had led to taxonomic and biogeographic reappraisal were refuted, and the current results support the resurrection of the genus Uromyias as the sister clade to Anairetes. The sister relationship between these two genera corresponds to an ecological dichotomy between a depauperate humid cloud forest clade and a diverse dry-tolerant clade that has diversified along the latitudinal axis of the Andes. The species-tree results and the concatenation results each reaffirm the primacy of mtDNA to provide phylogenetic signal for avian phylogenies at the species and subspecies level. This is due in part to the abundance of informative characters in mtDNA, and in part to its lower effective population size that causes it to more faithfully track the species tree.
A Tale of Three Circles

Everyone knows that the sum of the angles of a triangle formed by three lines in the plane is 180 ◦ , but is this still true for curvilinear triangles formed by the arcs of three circles in the plane? We invite the reader to experiment enough to see that the angle sum indeed depends on the triangle, and that no general pattern is obvious. We give a complete analysis of the situation, showing along the way, we hope, what insights can be gained by approaching the problem from several points of view and at several levels of abstraction. We begin with an elementary solution using only the most basic concepts of Euclidean geometry. While it is direct and very short, this solution is not complete, since it works only in a special case. The key to another special case turns out to be a model of hyperbolic geometry, leading us to suspect that the various manifestations of the problem lie on a continuum of models of geometries with varying curvature. This larger geometric framework reveals many beautiful unifying themes and provides a single method of proof that completely solves the original problem. Finally, we describe a very simple formulation of the solution, whose proof relies on transformations of the plane, a fitting ending we think, since a transformation may be regarded as a change in one’s point of view. The background developed earlier informs our understanding of this new perspective, and allows us to give a purely geometric description of the transformations needed. For the reader who is unfamiliar with the classical noneuclidean geometries, in which the notions of line and distance are given new interpretations, we provide an overview that is almost entirely self-contained. Such a reader will be introduced to such things as angle excess, stereographic projection, and even a sphere of imaginary radius. For the reader who is familiar with the three classical geometries, we offer some new ways of looking at them, which we are confident will reveal some surprises.
A two-stage synchronization technique for OFDM

A two-stage synchronization technique for OFDM is described and some simulated results of its performance are presented. These show the tendency of schemes based on correlation to pick a late timing point, which can cause degraded performance. The reasons behind this are analysed and a simple improvement is suggested.
Comparative physiological aspects of solute secretion by the eccrine sweat gland of the rat.

SummarySweat obtained from the sweat glands situated in the footpad of the rat was found to be a hypertonic solution with the following concentration of electrolytes (meq/liter): potassium, 149; sodium, 30; chloride, 80. Based on the descriptions of the fine structure of the rat sweat gland it is concluded that the “dark” (electron transparent cells of the secretory coil of the sweat are responsible for the secretion of potassium in sweat.
Including engineering students

The recruitment and retention of engineering students is a challenging process. Few students are choosing engineering as a major upon entry to college and over half of those who begin engineering do not graduate with an engineering degree. Research has shown that the sense of belonging or being "included" is a major factor in the retention of engineering students. Among the factors of a student who is at risk of dropping out are low income, minority, first-generation college, commuter, campus social isolation, and poor social adjustment. Recognizing the need for students to be included, the College of Engineering and Applied Sciences at Arizona State University has taken several steps to break down the walls of non-inclusiveness. A strong infrastructure for student support is contained in the Office of Student Affairs and Special Programs. Within this structure are special programs for recruiting and retaining female, ethnic minority and freshmen students. These programs and their impact on retention are discussed, with special attention paid to commuter students. An evaluation of the "inclusive" programs and plans for future endeavors are given.
A Field Study of Nitrogen Storage and Nitrate Reductase Activity in the Estuarine Macroalgae Enteromorpha lingulata (Chlorophyceae) and Gelidium pusillum (Rhodophyceae)

The purpose of this field study was to determine the relationship between environmental conditions, particularly high nitrate (NO 3 − ), low salinity events, and both nitrogen (N) storage (NO 3 − , ammonium [NH 4 + ], free amino acids [FAA], protein, and total N) and nitrate reductase (NR) activity in the macroalgaeEnteromorpha lingulata andGelidium pusillum in the lower Mobile Bay estuary (Alabama, USA). The environmental conditions at the collection site varied over the growing season with the most notable changes due to late winter and spring runoff entering the estuary (1–30 psu, 0.3–25.8 μM NO 3 − , 0.9–12.5 μM NH 4 + , 3–28°C, 61–2,375 μmol PAR m−2 s−1). Principal component analysis reduced the six environmental variables measured to three principal components. Stepwise, multiple regression analysis was then used to examine the relationship between the principal components and the internal NO 3 − , NH 4 + , and FAA pools and NR activity. The results indicate that changes in inorganic N availability and salinity rather than changes in irradiance determine patterns of N storage and NO 3 − reduction. BothE. lingulata andG. pusillum are capable of taking up and storing NO 3 − when it becomes available. Greater NO 3 − availability produced larger NH 4 + and FAA pools along with higher rates of NR activity inE. lingulata, but notG. pusillum, suggesting thatE. lingulata is able to metabolize NO 3 − more rapidly during high NO 3 − , low salinity events. Differences in the susceptibility ofE. lingulata andG. pusillum to NH 4 + inhibition and salinity stress combined with their different growth strategies help to explain the seasonal trends in total N. Total N inE. lingulata ranged from 2.57% to 6.39% dw, while the slower growingG. pusillum showed no significant variation in total N content (3.8–4.1% dw). These results led to the conclusion thatE. lingulata responds more quickly thanG. pusillum to high NO 3 − , low salinity events and that these events have a larger effect on the overall N content ofE. lingulata.
Fidelity of neural reactivation reveals competition between memories

Remembering an event from the past is often complicated by the fact that our memories are cluttered with similar events. Though competition is a fundamental part of remembering, there is little evidence of how mnemonic competition is neurally represented. Here, we assessed whether competition between visual memories is captured in the relative degree to which target vs. competing memories are reactivated within the ventral occipitotemporal cortex (VOTC). To assess reactivation, we used multivoxel pattern analysis of fMRI data, quantifying the degree to which retrieval events elicited patterns of neural activity that matched those elicited during encoding. Consistent with recent evidence, we found that retrieval of visual memories was associated with robust VOTC reactivation and that the degree of reactivation scaled with behavioral expressions of target memory retrieval. Critically, competitive remembering was associated with more ambiguous patterns of VOTC reactivation, putatively reflecting simultaneous reactivation of target and competing memories. Indeed, the more weakly that target memories were reactivated, the more likely that competing memories were later remembered. Moreover, when VOTC reactivation indicated that conflict between target and competing memories was high, frontoparietal mechanisms were markedly engaged, revealing specific neural mechanisms that tracked competing mnemonic evidence. Together, these findings provide unique evidence that neural reactivation captures competition between individual memories, providing insight into how well target memories are retrieved in the present and how likely competing memories will be remembered in the future.
The Impact of Childhood Maltreatment on Young Adults' Substance Abuse

Designed to establish a causal relationship between childhood victimization and young adults' substance abuse, this study also examined depression's role as mediator in that causal relationship. The study employs child-abuse measures that weigh both the type (sexual, physical) and the persistence of abuse. The study took as its substance-abuse measures the DSM-IV criteria for current alcohol abuse, current marijuana abuse, and current drug abuse. Data from the first 5 waves of the National Youth Survey (NYS) was employed, along with data from its 7th wave, to establish the temporal order needed to determine causal relationship. Childhood physical abuse proved a strong predictor of young adults' current substance abuse, although sexual abuse did not. Depression was shown to mediate the relationship of physical abuse to current alcohol abuse and current drug abuse, but not to current marijuana abuse.
Afirma GEC and thyroid lesions: An institutional experience

Background Thyroid fine-needle aspiration (FNA) is used to assess appropriate management of nodular thyroid lesions safely, but Bethesda category III (atypia of undetermined significance/follicular lesion of undetermined significance) and category IV (follicular neoplasm/suspicious for follicular neoplasm) lesions are problematic. This study aimed to evaluate the Afirma Gene Expression Classifier (GEC) results for lesions in those categories. Methods Medical records of patients with thyroid FNA and GEC results were obtained from archived material. Results were compared to thyroidectomy histologic diagnoses. Results Among 66 patients with FNA results (47 women and 19 men aged 26–89 years [mean, 59.4 years]), surgical reports were available for 38. Afirma GEC results were “nondiagnostic” for 10 of 66 (15.2%), “benign” for 22 (33.3%), and “suspicious” for 34 (51.5%). Surgical diagnosis was available for 38 of 66 patients (57.6%); GEC results for 6 (15.8%) of these were “nondiagnostic,” 27 (71.0%) were “suspicious,” and 5 (13.2%) were “benign.” One of 6 (16.7%) samples with “nondiagnostic” results, 1 of 5 (20%) with “benign” results, and 15 of 27 (55.6%) with “suspicious” results were malignant on histology. Papillary carcinoma was the most common tumor type (15 of 38; 39.5%). Conclusions Afirma GEC results minimize the number of unnecessary operations. Afirma GEC testing may be reserved for FNAs with a category III diagnosis on follow-up cytologic examination. We recommend a conservative approach for “suspicious” Afirma GEC results if Hurthle cells are seen with FNA. Diagn. Cytopathol. 2015;43:966–970. © 2015 Wiley Periodicals, Inc.
(2R,2′S)-2,2′-Bi­piperidine-1,1′-diium dibromide

The title compound, C10H22N22+·2Br−, was synthesized via reduction of 2,2′-dipyridyl with Ni–Al alloy/KOH, followed by separation of diastereoisomers (meso and rac) by recrystallization from ethanol. Although the two bridging C atoms are optically active, these two chiral centers adopt an (S,R) configuration; thus, the title compound contains an achiral meso form of 2,2′-bi­piperidine. Both of the piperidinium rings adopt chair conformations, and the two N atoms are trans to each other; an inversion center is located in the mid-point of the central C—C bond. The conformation of the organic moiety resembles that of 1,1′-bi(cyclo­hexa­ne). The organic di­ammonium cations are linked to each other through hydrogen bonding with bromide counter-ions, each of which forms two hydrogen bonds (N—H⋯Br) with two adjacent organic cations, thus linking the latter together in sheets parallel to (100).
The spectral dependence of electron central-axis depth-dose curves

Electron linac fields are usually characterized by the central‐axis practical range in water,R p , and the depth of half maximum dose, R 50, for dosimetry,quality assurance, and treatment planning. The quantitative relations between the range parameters and the intrinsic linac beam’s energy structure are critically reviewed. The spectral quantity 〈E 0〉* is introduced which is defined as the mean energy of the incident spectral peak, termed the ‘‘peak mean energy.’’ An analytical model is constructed to demonstrate the predicted relation between polyenergetic spectral shapes and the resulting depth‐dose curves. The model shows that, in the absence of electrons at the patient plane with energies outside about 〈E 0〉*±0.1〈E 0〉*, R p and R 50 are both determined by 〈E 0〉*. This analytical approximation is confirmed by a Monte Carlo calculation comparing two different idealized incident spectra. The effect of contaminant lower energy or wide‐angle scattered electrons is also discussed. The effect of the width of the intrinsic energy spread on the shape of the depth‐dose curve is investigated using Monte Carlo depth‐dose simulations based on measured linac energy spectra having energy spreads (full width at half maximum) as large as 20%. These simulations show that the energy spread has only a small effect on the shape of the central‐axis depth‐dose curve.
Organizational Newcomers' Acquisition of Information from Peers

Two studies focused on the particular processes by which organizational newcomers acquire information from their peers. Analysis of semistructured interviews with 30 nonsupervisory professional new hires at one organization and of questionnaires completed by 73 new hires from a variety of organizations and occupational groups indicated the types of information newcomers acquire from peers, the channels through which they acquire it, and the relationship between type and channel. Results also suggested that information acquisition is affected by type of organization entered, newcomer-peer work interactions, and newcomer occupation and experience level, but not by organizational size. Directions for future research on organizational entry processes and implications for practitioners are discussed.
Effect of Elevated Temperature on Deoxyribonucleic Acid Synthesis in Bacteriophage φ29-Infected Bacillus amyloliquefaciens

Deoxyribonucleic acid (DNA) synthesis in bacteriophage φ29-infected Bacillus amyloliquefaciens was studied at 37 and 45 C. Infectious intracellular particles appear at the same time at both temperatures, but the average burst size is reduced 45 to 50% at 45 C. There is a transient inhibition of cellular mass increase at 45 C which is not observed at the lower temperature. In addition, the rate of host DNA synthesis is reduced and the onset of viral-specific DNA replication is delayed for 6 to 9 min at 45 C. These findings allowed us to screen phage φ29 mutants which are sensitive to growth at 45 C for their ability to synthesize φ29 DNA in the absence of host DNA replication. We obtained mutants which make no viral DNA, reduced levels of DNA, or normal quantities of DNA under nonpermissive conditions. Pulse-labeled viral DNA which sediments more rapidly than mature φ29 DNA molecules was observed after gentle cell lysis and zone sedimentation. This DNA is not a precursor of normally sedimenting φ29 DNA and apparently consists of mature φ29 DNA molecules aggregated with large pieces of bacterial DNA.
Research in the cardiac intensive care unit

Successful clinical research entails the application of inductive reasoning and the scientific method to the investigation of problems in patient care. Testing appropriately formulated hypotheses reveals new principles from which we derive new therapeutic options. The cardiac intensive care unit challenges us to create an environment where basic tenets can be questioned without disturbing the orderly conduct of clinical care. We review the components of the scientific method and types of clinical investigations that are most pertinent to the cardiac intensive care unit. The advantages and disadvantages of prospective, retrospective, cross sectional and case control studies are reviewed. The conduct of clinical trials is reviewed with reference to appropriate statistical analysis as well as the opportunities and contraints that accompany intensive care-based research.
An automated assignment-free Bayesian approach for accurately identifying proton contacts from NOESY data

The identification of proton contacts from NOE spectra remains the major bottleneck in NMR protein structure calculations. We describe an automated assignment-free system for deriving proton contact probabilities from NOESY peak lists that can be viewed as a quantitative extension of manual assignment techniques. Rather than assigning contacts to NOESY crosspeaks, a rigorous Bayesian methodology is used to transform initial proton contact probabilities derived from a set of 2992 protein structures into posterior probabilities using the observed crosspeaks as evidence. Given a target protein, the Bayesian approach is used to derive probabilities for all possible proton contacts. We evaluated the accuracy of this approach at predicting proton contacts on 60 15N separated NOESY and 13C separated NOESY datasets simulated from experimentally determined NMR structures and compared it to CYANA, an established method for proton constraint assignment. On average, at the highest confidence level, our method accurately identifies 3.16/3.17 long range contacts per residue and 12.11/12.18 interresidue proton contacts per residue. These accuracies represent a significant increase over the performance of CYANA on the same data set. On a difficult real dataset that is publicly available, the coverage is lower but our method retains its advantage in accuracy over CANDID/CYANA. The algorithm is publicly available via the Protinfo NMR webserver http://protinfo.compbio.washington.edu/protinfo_nmr.