cssi/SciSciGPT-SciSciNet huggingface dataset:
Isotopic characteristics of canopies in simulated leaf assemblages

Abstract The geologic history of closed-canopy forests is of great interest to paleoecologists and paleoclimatologists alike. Closed canopies have pronounced effects on local, continental and global rainfall and temperature patterns. Although evidence for canopy closure is difficult to reconstruct from the fossil record, the characteristic isotope gradients of the “canopy effect” could be preserved in leaves and proxy biomarkers. To assess this, we employed new carbon isotopic data for leaves collected in diverse light environments within a deciduous, temperate forest (Maryland, USA) and for leaves from a perennially closed canopy, moist tropical forest (Bosque Protector San Lorenzo, Panama). In the tropical forest, leaf carbon isotope values range 10‰, with higher δ13Cleaf values occurring both in upper reaches of the canopy, and with higher light exposure and lower humidity. Leaf fractionation (Δleaf) varied negatively with height and light and positively with humidity. Vertical 13C enrichment in leaves largely reflects changes in Δleaf, and does not trend with δ13C of CO2 within the canopy. At the site in Maryland, leaves express a more modest δ13C range (∼6‰), with a clear trend that follows both light and leaf height. Using a model we simulate leaf assemblage isotope patterns from canopy data binned by elevation. The re-sampling (bootstrap) model determined both the mean and range of carbon isotope values for simulated leaf assemblages ranging in size from 10 to over 1000 leaves. For the tropical forest data, the canopy’s isotope range is captured with 50 or more randomly sampled leaves. Thus, with a sufficient number of fossil leaves it is possible to distinguish isotopic gradients in an ancient closed canopy forest from those in an open forest. For very large leaf assemblages, mean isotopic values approximate the δ13C of carbon contributed by leaves to soil and are similar to observed δ13Clitter values at forested sites within Panama, including the site where leaves were sampled. The model predicts a persistent ∼1‰ difference in δ13Clitter for the two sites which is consistent with higher water availability in the tropical forests. This work provides a new framework for linking contemporary ecological observations to the geochemical record using flux-weighted isotope data and lends insights to the effect of forest architecture on organic and isotopic records of ancient terrestrial ecosystems.
Comparing MR image intensity standardization against tissue characterizability of magnetization transfer ratio imaging

Purpose To evaluate existing methods of standardization by exploiting the well-known tissue characterizing property of magnetization transfer ratio (MTR) values obtained from MT imaging, and compare the tissue characterizability of standardized T2, proton density (PD), and T1 images against the MTR images. Materials and Methods Image intensity standardization is a postprocessing method that was designed to correct for acquisition-to-acquisition signal intensity variations (nonstandardness) inherent in magnetic resonance (MR) images. The main idea of this technique is to deform the volume image histogram of each study to match a standard histogram, and to utilize the resulting transformations to map the image intensities into a standard scale. The method has been shown to produce a significant gain in similarity of resulting images and to achieve numeric tissue characterization. In this work we compared PD-, T2-, and T1-weighted images before and after standardization with the corresponding MT images for 10 patient MRI studies of the brain, in terms of the normalized median values on the corresponding image histograms. Results No statistically significant difference was observed between the standardized PD-, T2-, and T1-weighted images and the corresponding MTR images. However, a statistically significant difference was found between the pre- and poststandardized PD-, T2-, and T1-weighted images, and between the prestandardized PD-, T2-, and T1-weighted images and the corresponding MTR images. Conclusion These results suggest that standardized T2, PD, and T1 images and their tissue-specific intensity signatures may be useful for characterizing disease. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc.
A sound barrier for silicon

For the first time in thirty five years, the clockspeed of the fastest commercial computer chips has not increased. Is the semiconductor industry just pausing for breath or about to suffer a fate similar to that of aerospace?
AADL and model-based engineering

Mission and safety critical software-reliant systems, aka. Cyber-physical systems, face the increasing challenges of exponential increase in verification related software rework cost. Industry studies show that 70% of defects are introduced in requirements and architecture design, while 80% are discovered post-unit test. The Architecture Analysis & Design Language (AADL) standard was targeted to address these issues through virtual system integration to analytically discover these system level issues regarding operational system properties early in the life cycle.After a summary of the challenges, the presentation highlights the expressive, analytical, and auto-generation capabilities of the AADL core language as well as several of its standardized extensions. The presentation then illustrates the importance of the analytical virtual system integration capabilities on several realistic industrial examples. In this context we discuss the benefit of well-defined semantics of nominal and fault behavior, timing, semantics of the model in AADL over other MBD notations.The presentation concludes by outlining a four part improvement strategy: architecture-led requirement specification to improve the quality of requirements, architecture refinement and incremental virtual system integration to discover issues early, compositional verification through static analysis to address scalability, and incremental verification and testing throughout the life cycle as assurance evidence.
Separation of the low-frequency mode from the inelastic continuum scattering of a sers active electrode

An I2 vapor cell and an optical multichannel analyzer allowed the simultaneous detection (from −60 to +60 cm−1) of inelastic scattering from a Ag electrode (electrochemically roughened in 0.1 M KI). Separation of the low-frequency mode, which peaks at ≈7 cm−1, from the inelastic continuum, which increases in intensity as ∣Δω∣→ 0, was accomplished by dividing the data (spectra) by the Bose-Einstein function. The potential dependence of the low-frequency mode and its spectral profile were investigated.
Metabotropic glutamate receptor expression in olfactory receptor neurons from the channel catfish, Ictalurus punctatus

Metabotropic glutamate receptors (mGluRs) were identified in olfactory receptor neurons of the channel catfish, Ictalurus punctatus, by polymerase chain reaction. DNA sequence analysis confirmed the presence of two subtypes, mGluR1 and mGluR3, that were coexpressed with each other and with the putative odorant receptors within single olfactory receptor neurons. Immunocytochemical data showed that both mGluR subtypes were expressed in the apical dendrites and some cilia of olfactory neurons. Pharmacological analysis showed that antagonists to each mGluR subtype significantly decreased the electrophysiological response to odorant amino acids. α-Methyl-L-CCG1/(2S,3S,4S)-2-methyl-2-(carboxycyclopropyl)glycine (MCCG), a known antagonist to mGluR3, and (S)-4-carboxyphenylglycine (S-4CPG), a specific antagonist to mGluR1, each significantly reduced olfactory receptor responses to L-glutamate. S-4CPG and MCCG reduced the glutamate response to 54% and 56% of control, respectively, which was significantly greater than their effect on a neutral amino acid odorant, methionine. These significant reductions of odorant response by the antagonists, taken with the expression of these receptors throughout the dendritic and ciliated portions of some olfactory receptor neurons, suggest that these mGluRs may be involved in olfactory reception and signal transduction. © 1998 John Wiley & Sons, Inc. J Neurobiol 35: 94–104, 1998
Limit loads on reinforced foundation soils

Reinforced soil is a practical solution to construction of unpaved roads or placement of footings over weak soils. A stability analysis of reinforced foundation soil is presented in this paper. A method is suggested for calculating limit loads on strip footings over foundation soils reinforced with horizontal layers of geosynthetics. Separate solutions are given for a case where reinforcement layers slip within the soil, and for a case where reinforcement ruptures. In the former case, an increase in the bearing capacity is dependent on the characteristics of the soil-reinforcement interface, whereas in the latter case it depends on the strength of the reinforcement. In both cases the increase in the limit load is dependent on the internal friction angle of the soil. Expressions are developed for quantitative predictions of bearing capacity of the foundation soil with horizontal layers of reinforcement. An optimum reinforcement depth is also given.
Intelligent simulation tools for mining large scientific data sets

This paper describes problems, challenges, and opportunities forintelligent simulation of physical systems. Prototype intelligent simulation tools have been constructed for interpreting massive data sets from physical fields and for designing engineering systems. We identify the characteristics of intelligent simulation and describe several concrete application examples. These applications, which include weather data interpretation, distributed control optimization, and spatio-temporal diffusion-reaction pattern analysis, demonstrate that intelligent simulation tools are indispensable for the rapid prototyping of application programs in many challenging scientific and engineering domains.
Epidural Pentobarbital Delivery Can Prevent Locally Induced Neocortical Seizures in Rats: The Prospect of Transmeningeal Pharmacotherapy for Intractable Focal Epilepsy

Summary: Purpose: To determine whether epidural pentobarbital (PB) delivery can prevent and/or terminate neocortical seizures induced by locally administered acetylcholine (Ach) in freely moving rats. Methods: Rats were implanted permanently with an epidural cup placed over the right parietal cortex with intact dura mater. Epidural screw-electrodes, secured to the cup, recorded local neocortical EEG activity. In the seizure-termination study, Ach was delivered into the epidural cup, and after the development of electrographic and behavioral seizures, the Ach solution was replaced with either PB or artificial cerebrospinal fluid (aCSF; control solution). In the seizure-prevention study, the epidural Ach delivery was preceded by a 10-min exposure of the delivery site to PB or aCSF. Raw EEG recordings, EEG power spectra, and behavioral events were analyzed. Results: Ach-induced EEG seizures associated with convulsions, which were unaffected by epidural aCSF applications, were terminated by epidurally delivered PB within 2–2.5 min. Epidural deliveries of PB before Ach applications completely prevented the development of electrographic and behavioral seizures, whereas similar deliveries of aCSF exerted no influence on the seizure-generating potential of Ach. Conclusions: This study showed for the first time that epidural AED delivery can prevent, as well as terminate, locally induced neocortical seizures. The findings support the viability of transmeningeal pharmacotherapy for the treatment of intractable neocortical epilepsy.
The location of the source of high-frequency solar acoustic oscillations

Recently Libbrecht and Jefferies et al. have reported regular peaks in the solar oscillation power spectrum extending well above 5.3 mHz, the maximum frequency of trapped acoustic modes. Kumar et al. argued that these peaks are primarily due to the interference of traveling waves which are excited due to acoustic emission from turbulent convection. In contrast with the standing wave P-mode frequencies below 5.3 mHz, the positions of the high-frequency interference peaks (HIPs) are dependent on the location of the source of the acoustic oscillations. In the present work, Kumar et al.'s argument is strengthened, and more importantly, use is made of the above dependence to determine the acoustic source strength as a function of depth. It is found that the acoustic source profile, and thus the convective velocity, is peaked about 200 km deeper than what is expected from standard mixing length theory.
Increased Persuasion Knowledge of Video News Releases: Audience Beliefs About News and Support for Source Disclosure

Video news releases (VNRs) have been criticized when they are used within a newscast without source disclosure because they violate ethical codes related to transparency and consumers' “right to be informed” by whom they are being persuaded. In an experiment, we show how increased persuasion knowledge about VNRs is positively related to beliefs in news commercialization, beliefs in VNR inappropriateness without disclosure, and support for disclosure of VNR material. We suggest that increased knowledge about VNRs without source disclosure measures might harm messages that are not employing the tactic (“false positives”) and lead to a general distrust of all media.
A variant in the fibrillin-3 gene is associated with TGF-β and inhibin B levels in women with polycystic ovary syndrome.

In an attempt to evaluate the association between allele 8 (A8) of D19S884 in the fibrillin-3 gene and circulating transforming growth factor (TGF) β and inhibin levels in women with polycystic ovary syndrome (PCOS), we studied 120 similarly aged women from families with PCOS and compared 40 women with PCOS who did not have A8 (A8− PCOS) with 40 women with PCOS who had A8 (A8+ PCOS) and 40 normally menstruating women who did not have either PCOS or A8 (A8− Non-PCOS). A8− PCOS is associated with higher levels of TGF-β1 compared with A8+ PCOS or A8− Non-PCOS, similar levels of TGF-β2 compared with A8+ PCOS but lower levels of TGF-β2 compared with A8− Non-PCOS, and lower levels of inhibin B and aldosterone compared with A8+ PCOS.
Sexual selection and a secondary sexual character in two Drosophila species

Evidence of sexual selection on male body size and on the number and symmetry of sternopleural bristles and of sex comb teeth was sought in natural populations of twoDrosophilaspecies. Body size did not differ between mating and non-mating males in either species. Mating maleD. simulanshad significantly fewer sex comb teeth than did males not found copulating, and mating maleD. pseudoobscurahad more sternopleural bristles. No difference in fluctuating asymmetry of any bilateral trait was found between mating and non-mating males. These observations suggest that generalizations that large body size and symmetry promote mating success are unfounded.
Sliding mode control of DC/DC multiphase power converters

The design of a multiphase DC/DC power converter with bounded switching frequency based on the sliding mode control concept is proposed whose main goal is the suppression of chattering. In the framework of this approach: the width of hysteresis loops of switching elements are selected such that oscillation frequency is the same in all phases; the switching command in each phase is chosen as a function of error signals from different phases where these functions are selected to have the best ldquoharmonic cancellationrdquo; and for any range of duty cycles the number of phases can be selected so that the amplitude of chattering is maintained at the desired level.
Role of Radiotherapy and Newer Techniques in the Treatment of GI Cancers

The role of radiotherapy in multidisciplinary treatment of GI malignancies is well established. Recent advances in imaging as well as radiotherapy planning and delivery techniques have made it possible to target tumors more accurately while sparing normal tissues. Intensity-modulated radiotherapy is an advanced method of delivering radiation using cutting-edge technology to manipulate beams of radiation. The role of intensity-modulated radiotherapy is growing for many GI malignancies, such as cancers of the stomach, pancreas, esophagus, liver, and anus. Stereotactic body radiotherapy is an emerging treatment option for some GI tumors such as locally advanced pancreatic cancer and primary or metastatic tumors of the liver. Stereotactic body radiotherapy requires a high degree of confidence in tumor location and subcentimeter accuracy of the delivered dose. New image-guided techniques have been developed to overcome setup uncertainties at the time of treatment, including real-time imaging on the linear accelerator. Modern imaging techniques have also allowed for more accurate pretreatment staging and delineation of the primary tumor and involved sites. In particular, magnetic resonance imaging and positron emission tomography scans can be particularly useful in radiotherapy planning and assessing treatment response. Molecular biomarkers are being investigated as predictors of response to radiotherapy with the intent of ultimately moving toward using genomic and proteomic determinants of therapeutic strategies. The role of all of these new approaches in the radiotherapeutic management of GI cancers and the evolving role of radiotherapy in these tumor sites will be highlighted in this review.
Evolution of a Theory: How Measurement Has Shaped Ayres Sensory Integration

Scientific theory evolves through phases. Scientists observe phenomena, classify their observations, examine and explain causation, and attempt to understand their results in varied circumstances. If anomalies are found that do not mesh with the theory, revision occurs, and the theory is improved (Christensen, Carlile, & Sundahl, 2001). Each stage requires accurate and precise measurement and, therefore, appropriate measurement tools. The body of scientific inquiry developed byA. JeanAyres is deeply rooted in systematic and methodical measurement, and her work marked the first effort by an occupational therapist to build a theory for clinical application with an evidence-based approach. The trajectory of the growth of Ayres Sensory Integration (ASI), beginning in the 1950s with continual advancements from the ongoing contributions of the researchers who have built on her seminal work since that time, has occurred simultaneously with the widespread use of more rigorous research methods, attention to measurement of fidelity, greater usage of exploratory and factor analysis, and more routine practice of examining multivariate research problems with computer statistical programs (Century, Rudnick, & Freeman, 2010; Elmore & Woehlke, 1988; Keselman et al., 1998; Ottenbacher & Peterson, 1985; Press, 2013; Tukey, 1980; West, Carmody, & Stallings, 1983). This special issue of the American Journal of Occupational Therapy consists of an impressive compilation of the widereaching application of the concepts that have evolved from those early efforts in measurement and that now continue to serve as a model for the profession, in line with the American Occupational Therapy Association’s (2007) Centennial Vision aiming toward “a powerful, widely recognized, science-driven, and evidence-based profession” (p. 613). This issue provides multiple examples of the improvements in methodological rigor that occupational scientists have brought to the study of ASI theory. The articles includemeasurement in sensory integration across age spans and diagnostic categories, with implications for theory and practice ranging fromassessment to intervention. In “The Issue Is” article by Schaaf et al. (2014), the current state of measurement in sensory integration is thoughtfully analyzed and articulated. In this editorial, we highlight the ways in which the foundations in measurement established by Ayres have evolved and how this earlier work connects with current and future trends.
INDIRECT EFFECTS AND TRADITIONAL TROPHIC CASCADES: A TEST INVOLVING WOLVES, COYOTES, AND PRONGHORN

The traditional trophic cascades model is based on consumer-resource interactions at each link in a food chain. However, trophic-level interactions, such as mesocarnivore release resulting from intraguild predation, may also be important mediators of cascades. From September 2001 to August 2004, we used spatial and seasonal heterogeneity in wolf distribution and abundance in the southern Greater Yellowstone Ecosystem to evaluate whether mesopredator release of coyotes (Canis latrans), resulting from the extirpation of wolves (Canis lupus), accounts for high rates of coyote predation on pronghorn (Antilocapra americana) fawns observed in some areas. Results of this ecological perturbation in wolf densities, coyote densities, and pronghorn neonatal survival at wolf-free and wolf-abundant sites support the existence of a species-level trophic cascade. That wolves precipitated a trophic cascade was evidenced by fawn survival rates that were four-fold higher at sites used by wolves. A negative correlation between coyote and wolf densities supports the hypothesis that interspecific interactions between the two species facilitated the difference in fawn survival. Whereas densities of resident coyotes were similar between wolf-free and wolf-abundant sites, the abundance of transient coyotes was significantly lower in areas used by wolves. Thus, differential effects of wolves on solitary coyotes may be an important mechanism by which wolves limit coyote densities. Our results support the hypothesis that mesopredator release of coyotes contributes to high rates of coyote predation on pronghorn fawns, and demonstrate the importance of alternative food web pathways in structuring the dynamics of terrestrial systems.
Large Aggregate Distribution During the JGOFS North Atlantic Bloom Experiment

Profiles made during the North Atlantic Bloom Experiment with a Large Aggregate Profiling System (LAPS) recorded the concentration and distribution of particles in the marine snow-size range (>0.5 mm diameter) while simultaneously recording salinity, temperature, depth, and beam attenuation. Five profiles were made at the 47°N, 20°W station. To measure diel variations, four profiles were made within a 24-hour period (April 19–20, 1989); a fifth profile was made two days later.
On the radial filling of a rotating cylinder

Some aspects of the radial filling of a finite rotating cylinder are considered in the limit of a small Ekman number E. Three main cases are distinguished by the value of τ F , the ratio of filling and spin-up times. When τ F [Lt ] 1 the effect of the Ekman layers is unimportant and new fluid accumulates behind that already contained by an essentially radial flux. For τ F ∼ 1 the Ekman layers are active and entering fluid is added both ahead and behind the initially contained fluid core. which undergoes a process similar to spin-up with the notable difference that here the Ekman layers are non-divergent. In both cases the Rossby number e is 0(1). When τ F [Gt ] 1, e is small and the Ekman layers control the (quasi-steady) filling. The new fluid is then transported through boundary layers and spread on the moving front from the inside throughout an E ¼ layer imbedded in a weak E 1/3 layer.
Solution processing of CIGS absorber layers using a hydrazine-based approach

A simple solution-based approach has been developed for CIGS absorber layer deposition, employing hydrazine as the solvent for all metal chalcogenide components. Advantages of the technique include the molecular (rather than nano or microparticle) nature of the precursor solutions, which enables intimate mixing of the various CIGS components before the final heat treatment, the absence of carbon, oxygen and other common contaminants from the solution, and the lack of need for a post deposition selenization treatment to achieve highquality CIGS films. Relatively smooth and compact films, with up to μm-scaled thicknesses and grain sizes, have been achieved by spin coating. Gallium and sulfur have been successfully incorporated into the Cu 1−z In 1−x Ga x Se 2−y S y layers for x≪0.5, y≪0.6 and z≪0.15. Preliminary PV devices based on a glass/Mo/CIGS/CdS/i-ZnO/ITO structure and employing the solution-processed CIGS films have yielded efficiencies of up to 10% (AM 1.5 illumination).
Angiotensin stimulates glucose and fluid absorption by rat proximal straight tubules.

I investigated the effect of angiotensin on glucose and fluid absorption by isolated, perfused rat proximal straight tubules. During the control period, tubules absorbed fluid at 0.68 +/- 0.05 nL/mm.min and glucose at 12.5 +/- 1.3 pmol/mm.min. After 10(-10) M angiotensin was added to the bath, tubules absorbed fluid at 0.82 +/- 0.06 nL/mm.min and glucose at 16.0 +/- 2.4 pmol/mm.min--a stimulation of both parameters by 30%. Time controls showed no significant change in the rate of glucose or fluid absorption. This stimulation was due to an increase in the maximum rate of transport. The maximum rate of glucose absorption with 5.5 mM in bath and perfusate increased from 14.5 +/- 1.6 pmol/mm.min to 18.5 +/- 1.4 pmol/mm.min after 10(-10) M angiotensin was added to the bath. In contrast, the Km for glucose did not change, since a solution containing 0.55 mM glucose (approximately Km) supported 63 +/- 6% of the maximum rate during the control period and 60 +/- 5% of the maximum rate after angiotensin was added to the bath. Angiotensin also had no effect on glucose permeability, which was (3.7 +/- 0.4) x 10(-6) cm/s before treatment and (3.8 +/- 0.4) x 10(-6) cm/s after treatment. From these data, it is concluded that: (1) angiotensin stimulates glucose absorption in the rat proximal straight tubule; (2) this stimulation is the result of an increase in the maximum rate of transport rather than a change in Km or permeability; and (3) stimulation of Na/glucose absorption by angiotensin accounts for a significant portion of the increase in fluid absorption caused by angiotensin.
SiiE Is Secreted by the Salmonella enterica Serovar Typhimurium Pathogenicity Island 4-Encoded Secretion System and Contributes to Intestinal Colonization in Cattle

Here we report that Salmonella enterica serovar Typhimurium pathogenicity island 4 carries a type I secretion system (siiCDF) which secretes an ∼600-kDa protein (encoded by siiE). SiiE is surface expressed, and its production is regulated by HilA. SiiE and SiiF influence colonization in cattle and the invasion of bovine enterocytes.
Cytokeratin Expression in Seminoma of the Human Testis

We studied cytokeratin (CK) expression immunohistochemically in 64 seminomas using a panel of commercially available antikeratin antibodies and tested for association of CK expression with patient age, tumor size, stage, and outcome. Seventeen embryonal carcinomas were compared with seminoma. CK7, CAM 5.2, AEI/AEIII, and wide-spectrum screening keratin (WSK) were positive in 41%, 30%, 36%, and 36% of the seminomas, respectively. CK20 and high-molecular-weight keratin (HMWK) were negative in all cases. CD30, placental alkaline phosphatase (PLAP), and epithelial membrane antigen (EMA) were positive in 6%, 100%, and 2% of cases, respectively. There were no differences in patient age, stage, tumor size, or outcome between CK-positive and CK-negative seminomas. CK7, CAM 5.2, AEI/AEIII, and WSK were positive in 100%, 88%, 94%, and 88% of embryonal carcinomas, respectively. CK20 and HMWK were negative in all cases. CD30, EMA, and PLAP were positive in 100%, 12%, and 76%, respectively. CKs are present in seminoma, and their presence is not associated with a difference in patient age, stage, or outcome. In cases such as small needle biopsy specimens, CK and CD30 stains may be useful in separating seminoma from embryonal carcinoma. The intermediate filaments are an integral part of the cytoskeleton, and the family of intermediate filaments consists of desmin, vimentin, cytokeratin, glial, and neurofilaments. 1 The cytokeratins are the largest and most diverse group of intermediate filaments in human cells. Their presence is indicative of epithelial differentiation, and they are present in normal and neoplastic epithelia. 2 The cytokeratins are expressed in a characteristic pattern in different epithelia, a pattern that often is maintained during neoplastic transformation. 3-9 Cytokeratin filaments typically are not found in germinal, mesenchymal,
Bestrophins and Retinopathies

Best vitelliform macular dystrophy (BVMD, also called Best's disease) is a dominantly inherited, juvenile-onset form of macular degeneration, which is characterized by abnormal accumulation of yellow pigment in the outer retina and a depressed electro-oculogram light peak (LP). Over 100 disease-causing mutations in human bestrophin-1 (hBest1) are closely linked to BVMD and several other retinopathies. However, the physiological role of hBest1 and the mechanisms of retinal pathology remain obscure partly because hBest1 has been described as a protein with multiple functions including a Ca2+-activated Cl- channel, a Ca2+ channel regulator, a volume-regulated Cl- channel, and a HCO3- channel. This review focuses on how dysfunction of hBest1 is related to the accumulation of yellow pigment and a decreased LP. The dysfunction of hBest1 as a HCO3- channel or a volume-regulated Cl- channel may be associated with defective regulation of the subretinal fluid or phagocytosis of photoreceptor outer segments by retinal pigment epithelium cells, which may lead to fluid and pigment accumulation.
A simple model of dynamic interactions between respiratory centers

There is a general consensus that neurons responsible for the generation of a respiratory rhythm are located in the rostral ventrolateral medulla. However, there is still controversy regarding the necessary components for respiratory rhythm generation. Both inspiratory neurons in the preBotzinger complex (preBOtC) and pre-inspiratory neurons located more rostrally to this anatomical structure referred to as the parafacial respiratory group (pFRG) have been proposed to be essential for respiratory rhythmogenesis. To study the dynamical interactions between preBOtC and pFRG neurons, we use a canonical model that describes each neuron population as a phase oscillator. We assume that the oscillators are weakly coupled with pFRG neurons providing stimulation to preBOtC neurons and preBOtC neurons providing inhibitory drive to pFRG neurons. In our mathematical study, we explore plausible mechanisms that may account for the complex interactions between I and pre-I neuron. In particular, we show that reduced excitability of inspiratory in preBOtC may lead to the phenomena known as "quantal slowing"
On the role of conserved histidine 106 in 10-formyltetrahydrofolate dehydrogenase catalysis: connection between hydrolase and dehydrogenase mechanisms.

The enzyme, 10-formyltetrahydrofolate dehydrogenase (FDH), converts 10-formyltetrahydrofolate (10-formyl-THF) to tetrahydrofolate in an NADP+-dependent dehydrogenase reaction or an NADP+-independent hydrolase reaction. The hydrolase reaction occurs in a 310-amino acid long amino-terminal domain of FDH (Nt-FDH), whereas the dehydrogenase reaction requires the full-length enzyme. The amino-terminal domain of FDH shares some sequence identity with several other enzymes utilizing 10-formyl-THF as a substrate. These enzymes have two strictly conserved residues, aspartate and histidine, in the putative catalytic center. We have shown recently that the conserved aspartate is involved in FDH catalysis. In the present work we studied the role of the conserved histidine, His106, in FDH function. Site-directed mutagenesis experiments showed that replacement of the histidine with alanine, asparagine, aspartate, glutamate, glutamine, or arginine in Nt-FDH resulted in expression of insoluble proteins. Replacement of the histidine with another positively charged residue, lysine, produced a soluble mutant with no hydrolase activity. The insoluble mutants refolded from inclusion bodies adopted a conformation inherent to the wild-type Nt-FDH, but they did not exhibit any hydrolase activity. Substitution of alanine for three non-conserved histidines located close to the conserved one did not reveal any significant changes in the hydrolase activity of Nt-FDH. Expressed full-length FDH with the substitution of lysine for the His106 completely lost both the hydrolase and dehydrogenase activities. Thus, our study showed that His106, besides being an important structural residue, is also directly involved in both the hydrolase and dehydrogenase mechanisms of FDH. Modeling of the putative hydrolase catalytic center/folate-binding site suggested that the catalytic residues, aspartate and histidine, are unlikely to be adjacent to the catalytic cysteine in the aldehyde dehydrogenase catalytic center. We hypothesize that 10-formyl-THF dehydrogenase reaction is not an independent reaction but is a combination of hydrolase and aldehyde dehydrogenase reactions.
Art-Song Reworkings: An Overview

Broadly speaking, we can divide Renaissance polyphony into five groups: works not using any pre-existent material, and pieces based on sacred monophony, secular monophony, sacred polyphony or secular polyphony. This is not the common way to classify Renaissance compositions. The more normal breakdown is by the technique applied to the pre-existent material – cantus firmus, paraphrase, parody – regardless of what that material was. Yet much is to be gained by starting with the original material, and that was, after all, what the composer probably did at least some of the time.
Communication and the Semiotics of Space

The purpose of this article is to explicate some common situations relevant to communication and the semiotics of space. Semiotics provides a systemic way to analyse and understand the characteristics of signs expressing meaning. In everyday life space is rarely considered for its independent qualities, but is more generally taken as a category of conceptions that act as a background, or a context for the meaning of other objects. The study of space as a semiotic phenomenon suggests that the meaning of space, as a sign, is generally understood in relation to other concerns. Communication draws attention to the content of messages while space contributes to the meanings of those messages without being obvious about its role in constructing meaning.
RATES OF EVOLUTION OF HYBRID INVIABILITY IN BIRDS AND MAMMALS

Almost 30 years ago, A. C. Wilson and colleagues presented results indicating that hybrid inviability between species evolves 10 times faster in mammals than in birds and frogs. Here I revisit this question for birds and mammals using modern molecular data (mitochondrial cytochrome b DNA) and a more phylogenetically appropriate statistical approach. My analyses confirm that diverging mammals lose the ability to form viable hybrids faster than birds. To explain the difference in rates of evolutionary loss of hybridization potential, Wilson and coworkers proposed that mammals have higher rates of regulatory evolution, causing higher probabilities of developmental incompatibilities between mammal species. I briefly discuss this and other potential explanations.
A LAND PLANT NOT A SPONGE: A RE-EVALUATION OF THE MISSISSIPPIAN DEMOSPONGE VINTONIA AND THE FAMILY VINTONIIDAE

In 1956 two fossil specimens were exposed in concretions associated with two crushed body chambers of the orthoconic nautiloid Rayonnoceras sp. recovered from the Fayetteville Shale (Chesterian, upper Mississippian) of northern Arkansas. The two specimens were subsequently described as a new genus and species of demosponge, Vintonia doris Nitecki and Rigby and placed in the new family Vintoniidae (Nitecki and Rigby, 1966). The specimens were described as silicified. Nitecki and Rigby's analysis, based on the presence of an assumed skeletal net resembling the spongin net of Recent sponges, suggested that the specimens were demosponges with sycon structure. The “net” was considered spongin because of its geometric pattern and cellular appearance. That interpretation led to the placement of the specimens in the Order Keratosida despite the presence of an apparently well-developed ectosomal region, a feature that is not common in the Keratosida (Nitecki and Rigby, 1966). As part of ongoing studies of goniatite ammonoid and orthoconic nautiloid associations in shales by RHM, one of the two nautiloid body chambers and the prepared thin-sections were loaned to RHM in 1999. Re-examination of the thin sections revealed that the specimens do not represent sponges, but are fragments of badly degraded and broken plant axes that probably belonged to seed fern petioles or stems. The specimens are deposited at the Field Museum of Natural History, Chicago, IL under the collection numbers B-56–1095, 1096, 1098–1102 and PE 10098, with locality labels that read “?Town Creek, City of Fayetteville, Washington County, Arkansas.” However the precise outcrop of the crushed nautiloid body chambers and specimens in this study is uncertain because there are numerous exposures in Town Branch Creek system that have …
Assessment of Skeletal Growth and Maturation of Premature and Term Macaca nemestrina

Primate nurseries have traditionally collected weight and intake data to construct growth norms for their populations. The purpose of this paper is to suggest supplementing these data with skeletal maturation and linear body growth information. Methods of assessment used at the Infant Primate Research Laboratory at the University of Washington are presented, using as an example a current study which contrasts the physical growth and ossification status of premature and term-gestation pigtail macaques (Macaca nemestrina). The postnatal growth and development of the macaque is of special interest as a model for the human infant. The fetal and infant growth of the macaque is similar to the human skeletal growth and maturation process (Kerr, 1975; Newell-Morris and Tarrant, 1978). Hand and foot ossification is much more rapid than in the human, reducing follow-up time for the appearance of round bones and epiphyses to months instead of years of postnatal age. Previous studies have indicated the value of ossification onset and increments as measures of skeletal maturity (Pryor, 1906; Flory, 1936; Garn and Rohmann, 1959, 1968; van Wagenen and Asling, 1964; Kerr, 1975). Skeletal growth and ossification assess­ment can provide a more detailed picture of infant maturation status than age estimates and weight alone and may have predic­tive value for later growth and development.
Preventing Health Emergencies in An Unobtrusive Way

The Ambient Intelligence (AmI) paradigm represents the vision of the next wave of computing. By relying on various computing and networking techniques, AmI systems have the potential to enhance our everyday lives in many different aspects. One area in which widespread application of this innovative paradigm promises particularly significant benefits is health care. The work presented here contributes to realizing such promise by proposing a functioning software application able to learn the behaviors and habits, and thereby anticipate the needs, of inhabitants living in a technological environment, such as a smart house or city. The result is a health care system that can actively contribute to anticipating, and thereby preventing, emergency situations to provide greater autonomy and safety to disabled or elderly occupants, especially in cases of critical illness.
Plane Periodic Flow Predictions for Fusiform Aneurysms

Pathological bulges or dilatations of an artery are found in a variety of forms at diverse locations in the vasculature. In this paper, unsteady flow solutions in a two-dimensional wavy channel are obtained using the conservative form of the vorticity transport equation. A simple transformation is employed to shift the finite-difference calculations to a rectangular field where square meshes are used. The aneurysms geometrics selected for study showed that the main kinematic and kinetic activity was concentrated in the region near the cavity at all times except near flow reversal. At this time, the vortex that was created within the cavity and that had been trapped there were ejected.
Thoracoscopy: medical versus surgical—in the management of pleural diseases

Diseases of the pleura continue to affect a large population of patients worldwide and in the United States. Pleural fluid analysis and accompanying imaging of the pleura including chest X-rays, chest computed tomography (CT) scan and chest ultrasonography are among the first steps in the management of pleural effusions. When further diagnostic or therapeutic work up is necessary, open thoracotomy and thoracoscopy come to mind. However, given the significant morbidity and mortality associated with open thoracotomy, and the advances in medicine and medical instruments, thoracoscopy has now become a routine procedure in the management of the disease of the chest including pleura. Debates about surgical vs. medical thoracoscopy (MT) are ongoing. In the following pages we review the literature and discuss the similarities and differences between the two procedures, as well as their indications, contraindications, complications and efficacy in the management of pleural diseases.
Geometric Convergence of Adaptive Monte Carlo Algorithms for Radiative Transport Problems Based on Importance Sampling Methods

Importance sampling is a very well-known variance-reducing technique used in Monte Carlo simulations of radiative transport. It involves a distortion of the physical (analog) transition probabilities with the goal of causing events of interest in the computation to occur more frequently than in the analog process. This distortion is then compensated by a corresponding alteration of the estimating random variable in order to remove any bias from the estimates of quantities of interest. In this paper, we construct several families of estimators based on importance sampling methods to solve general transport problems and prove that the adaptive application of each estimator produces geometric convergence of the approximate solution. We also present numerical results that illustrate important elements of the theory.
The Chinese Insurance Industry

This special edition focuses on certain issues in the Chinese insurance industry. Examining these issues is important because the Chinese insurance industry has grown significantly in the last 20 y...
The Faces of Biology Documented in Annual Photo Contest

What do snowy owls, insect specimens, and Amazonian forests have in common? They are the subjects of the winning photos for the 2015 Faces of Biology Photo Contest. The photo contest, which is sponsored by the American Institute of Biological Sciences (AIBS), is an opportunity for members of the scientific community to showcase the varied forms that biological research takes. The photographs will be used to help the public and policymakers better understand the nature and importance of biological research and education. “We are increasingly talking of STEAM, not just STEM. There is a growing appreciation for the value of incorporating the arts into how we do, teach, and communicate science,” said Robert Gropp, interim co-executive director of AIBS. “I am so pleased that for the past five years, AIBS has been recognizing outstanding photographers who have the ability to help us communicate about how research is done.” Submissions must depict a person engaging in biological research or education. Entries are judged on how well they fit the theme of the contest; creativity; and composition, clarity, and technical quality. Professional photographer Florencia Mazza Ramsay has spent years photographing fashion models, but recently, she became interested in science as a subject for her photos. Last year, Mazza Ramsay spent three months in Alaska documenting Arctic research, local culture, and the impacts of climate change. Her photograph of owl researcher Denver Holt won first place in the contest and appears on the cover of this issue of BioScience. Holt was documenting a nest of 2-day-old snowy owlets. At each nest, he noted the condition of the owlets and the types of captured prey—in this photo, a rodent and a partially eaten bird are visible. As Mazza Ramsay pointed out, clearly, “their parents were doing a good job at keeping food at the nest.” Mazza Ramsay offers the following advice to scientists who want to share their research with the public through photography: “Bringing a photographer to document your work in the field might seem like a crazy idea, but I think it’s 100 percent worth it. I know nowadays everybody can carry a GoPro or even a DSLR [digital single-lens reflex camera] with them, but it’s not the same as having someone 100 percent into observing while you just worry about the science.”
Knowledge in motion: the evolution of HIV/AIDS research

Many contemporary social and public health problems do not fit neatly into the research fields typically found in universities. With this in mind, researchers and funding agencies have devoted increasing attention to projects that span multiple disciplines. However, comparatively little attention has been paid to how these projects evolve over time. This relative neglect is in part attributable to a lack of theory on the dynamic nature of such projects. In this paper, we describe how research programs can move through various states of integration including disciplinarity, multidisciplinarity, interdisciplinarity and transdisciplinarity. We link this insight to computational techniques--topic models--to explore one of the most vibrant and pressing contemporary research areas--research on HIV/AIDS. Topic models of over 9000 abstracts from two prominent journals illustrate how research on HIV/AIDS has evolved from a high to a lower level of integration. The topic models motivate a more detailed historical analysis of HIV/AIDS research and, together, they highlight the dynamic nature of knowledge production. We conclude by discussing the role of computational social science in dynamic models of interdisciplinarity.
A Peculiar Property of the Primitive Roots of 13

(1941). A Peculiar Property of the Primitive Roots of 13. The American Mathematical Monthly: Vol. 48, No. 3, pp. 185-187.