cssi/SciSciGPT-SciSciNet huggingface dataset:
Permineralized Alethopteris ambigua (Lesquereux) White: A medullosan with relatively long-lived leaves, adapted for sunny habitats in mires and floodplains

Abstract Permineralized Alethopteris ambigua (Lesquereux) White occurs in the Kalo Formation (Moscovian, Pennsylvanian) of Iowa. The following characteristics distinguish A. ambigua from other permineralized Alethopteris species: narrow pinnule width, a deeply sunken midrib having a round cross-section, deep midline depth, and a thick lamina that is not enrolled. Both the new permineralized Alethoptheris from the Kalo Formation and adpressed A. ambigua (Lesquereux) White have ‘pecopteroid’ pinnules with lamina that are linked at the base. Because the midrib of A. ambigua is round in cross-section, the widest part of the midrib lies below the midrib–lamina junction. In adpression this configuration would produce the ‘midrib flanges’ found in adpressed A. ambigua from Missouri. Three Alethopteris species with narrow pinnules and pecopteriod insertion have been extensively synonomized by previous workers: A. ambigua (Lesquereux) White, Alethopteris friedelii P. Bertrand, and Alethopteris lesquereuxii Wagner. Together with Alethopteris leonensis Wagner, these four species form a morphological continuum similar to other alethoperid morphological continua (e.g. the Alethopteris densinervosa, Alethopteris ingbertensis, Alethopteris lonchitifolica, Alethopteris missouriensis, Alethopteris westphalensis continuum). Nonetheless, because their permineralized forms can be readily distinguished, we favor retention of both A. ambigua (Lesquereux) White and A. lesquereuxii Wagner. Most permineralized mire alethopterids, with the exception of Alethopteris sp. from the Lewis Creek deposit (Kentucky, U.S.A.), have anatomical features consistent with foliage that grew in sunny, wet or humid habitats, including thick photosynthetic lamina, thick cuticle and enrolled edges. Most permineralized mire neuropterids, with the exception of Laveineopteris rarinervis from the Illinois Basin, have anatomical features consistent with foliage that grew in shady, wet or humid habitats, including thin photosynthetic lamina, and thin cuticle. In seed-ferns with broadly attached pinnules and compound leaves, lamina thickness/pinnule width (LT/MaxW) is a proxy for leaf mass per area (LMA), and indicates the relative economic cost and longevity of medullosan foliage. Measures of LT/MaxW for mire medullosans suggest that most mire alethopterids produced metabolically-expensive, long-lived fronds, whereas most mire neuropterids produced metabolically-cheap, short-lived fronds.
From neural development to cognition: unexpected roles for chromatin

Recent genome-sequencing studies in human neurodevelopmental and psychiatric disorders have revealed mutations in chromatin-modifying enzymes, such as chromatin remodellers and histone-modifying enzymes. Such studies are improving our understanding of the roles of these modifiers in human neurodevelopment, and this article discusses the emerging roles for several of these enzymes in development and disease.
Thermal Expansion Measurements of Cryoprotective Agents

As part of an ongoing effort to characterize the mechanical behavior of biological tissues in the cryogenic temperature range, the current study focuses on the thermal expansion measurements of cryoprotective agents. This study focuses particularly on the upper part of the cryogenic temperature range, where the cryoprotectant behaves like low viscous liquid at all practical cooling rates. A new experimental apparatus for thermal expansion measurements is presented in this report. This report includes thermal expansion measurements of the cryoprotectant mixtures DP6 and VS55, and comparison with data from the literature on DMSO solutions.Copyright © 2003 by ASME
Forces and torque in a magnetically actuated harmonic motor

The objective of this work is the calculation of forces and torque for a new type of motor, the harmonic motor, intended specifically for operation of brakes in vehicles. The motor offers the promise of eliminating a number of design limitations of existing electromechanical actuator systems. First, the motor eliminates the need for a gear set. This reduces the complexity of the package, which could result in a less expensive, more reliable, lighter and smaller overall package. Second, the harmonic motor inherently provides zero-force back-drivability and fails silent, greatly expanding the design space and simplifies the system fault analysis. Third, the motor has a low rotational inertia that could be used to improve the dynamic response of the system, improving both stopping distances and anti-lock braking control-ability. This work discusses a preliminary structure intended to show that the performance characteristics can be met and in particular that a specified torque can be obtained within given dimensional constraints. Simple analytical calculations based on magnetic circuits are first used to initiate linear and nonlinear finite element calculations of fields of forces.
Catalyst-Free Growth of Ordered Single-Walled Carbon Nanotube Networks

We report the catalyst-free horizontal growth of carbon nanotubes on the Si face of hexagonal silicon carbide (6H-SiC) at temperatures above 1500 °C. These nanotubes are single walled with a very narrow distribution of diameters. Nanotubes tend to follow the atomic structure of the surface, leading to preferential orientation and the development of ordered networks of tubes. Manipulation of nanotubes using atomic force microscopy indicates that the tubes move on the surface at high temperature and are stabilized in the directions parallel and perpendicular to the step edges.
Repacking the Core of T4 lysozyme by automated design

Automated protein redesign, as implemented in the program ORBIT, was used to redesign the core of phage T4 lysozyme. A total of 26 buried or partially buried sites in the C-terminal domain were allowed to vary both their sequence and side-chain conformation while the backbone and non-selected side-chains remained fixed. A variant with seven substitutions ("Core-7") was identified as having the most favorable energy. The redesign experiment was repeated with a penalty for the presence of methionine residues. In this case the redesigned protein ("Core-10") had ten amino acid changes. The two designed proteins, as well as the constituent single mutants, and several single-site revertants were over-expressed in Escherichia coli, purified, and subjected to crystallographic and thermal analyses. The thermodynamic and structural data show that some repacking was achieved although neither redesigned protein was more stable than the wild-type protein. The use of the methionine penalty was shown to be effective. Several of the side-chain rotamers in the predicted structure of Core-10 differ from those observed. Rather than changing to new rotamers predicted by the design process, side-chains tend to maintain conformations similar to those seen in the native molecule. In contrast, parts of the backbone change by up to 2.8 A relative to both the designed structure and wild-type. Water molecules that are present within the lysozyme molecule were removed during the design process. In the redesigned protein the resultant cavities were, to some degree, re-occupied by side-chain atoms. In the observed structure, however, water molecules were still bound at or near their original sites. This suggests that it may be preferable to leave such water molecules in place during the design procedure. The results emphasize the specificity of the packing that occurs within the core of a typical protein. While point substitutions within the core are tolerated they almost always result in a loss of stability. Likewise, combinations of substitutions may also be tolerated but usually destabilize the protein. Experience with T4 lysozyme suggests that a general core repacking methodology with retention or enhancement of stability may be difficult to achieve without provision for shifts in the backbone.
The human ecosystem Part II: Social indicators in ecosystem management

The human ecosystem model presented in an accompanying article in this issue (Machlis et al. 1997) has several applications. One such application is as an organizing concept in selecting social indicators for ecosystem management. This article describes a contemporary example of such an application using the Upper Columbia River Basin (UCRB). Social indicators are statistics that can be collected over time and used for policy and management. The human ecosystem model provides a rationale for selecting specific social indicators to assess socioeconomic conditions. In the UCRB example, data ‐were collected from 1990 U.S. Census documents and other secondary data sources for 39 indicators. In this article, two indicators are presented as examples for all 57 counties in the study area. Applications of social indicators for ecosystem management are discussed, such as (1) monitoring social conditions; (2) doing comparative studies within a region, between regions, and overtime; (3) evaluating human ecosystem re...
G Protein–Coupled Receptor Signalling in the Kidney

Abstract The kidney is responsible for regulation of water and electrolyte balance, filtration and absorption of plasma proteins, and control of blood volume and pressure. Homeostasis achieved by the kidney is controlled in large part by the action of hormones or proteins on specific transmembrane receptors. Conversely, many renal diseases, including that resulting from atherosclerosis, are characterised by scarring and abnormal proliferation of cellular components of the kidney, and these processes are mediated in large part by these same receptors. The G protein–coupled receptors constitute a large and diverse class of proteins, characterised by the possession of seven transmembrane-spanning domains. These receptors bind polypeptide growth factors, which function to transmit a variety of signals from the extracellular to the intracellular milieu. The receptor-associated G proteins utilised by the kidney derive their specificity not only by activating or inhibiting various second-messenger molecules, but also by their location on particular cell types. In this review, several G protein–coupled receptors will be discussed from the perspective of their importance to kidney function and to the pathogenesis of renal disease, atherosclerosis, and hypertension.
Object-Representations and Object-Relationships in Rorschach Responses

Abstract This paper presents an object-relational view of Rorschach content. The existence within the self of images of others is a pre-condition of social development. The availability of a repertoire of personal imagery, the range and emotional quality of one's representations of others, the degree of fusion which tends to occur between self and others, the characterization of self and others, and the kinds of expectancies one carries into each encounter with the people and things of his world — all are facets of a person's relationship potential which, it is suggested, may be inferred from the content of a Rorschach protocol. Patients' general level of psychopathology and some more specific attributes of their psychopathology inferred from Rorschach content proved to be highly effective indicators of the psychopathology revealed in extensive psychiatric, psychological and social work interviews.
Three-dimensional live microscopy beyond the diffraction limit

In fluorescence microscopy it has become possible to fundamentally overcome the diffraction limited resolution in all three spatial dimensions. However, to have the most impact in biological sciences, new optical microscopy techniques need to be compatible with live cell imaging: image acquisition has to be fast enough to capture cellular dynamics at the new resolution limit while light exposure needs to be minimized to prevent photo-toxic effects. With increasing spatial resolution, these requirements become more difficult to meet, even more so when volumetric imaging is performed. In this review, techniques that have been successfully applied to three-dimensional, super-resolution live microscopy are presented and their relative strengths and weaknesses are discussed.
Stochastic model to describe atmospheric attenuation from yearly global solar irradiation

Abstract A new stochastic model to describe atmospheric attenuation from yearly global solar irradiation has been developed and implemented. The proposed model takes into account the consideration that the whole of all attenuating elements can be thought of as a population where the higher the number of individuals the lesser the clearness index. Thus, the inverse of the clearness index is considered as the variable of a stochastic process. From the proposed master equation as starting point, the new model is characterized by transition rates (assessed from a growing parameter - G - and a decreasing parameter - D) which depend mainly on the climatological characteristics at each location. In this sense, different regions with an attenuation level calculated from the yearly global irradiation have been established using the Koppen–Geiger climate classification as a first approach. The model parameters G and D have been determined for different regions using the inverse of the clearness index as variable. The probability density function obtained after the application of the stochastic model for each climate zone shows how the index mode increases from the zones with lower levels of attenuation to those with higher levels of attenuation. This result confirms the proposed null hypothesis related to the use of the inverse of the clearness index as an attenuation population indicator. The fit between the empirical data and the data provided for the model is good enough according to a Kolmogorov–Smirnov test with a significance level of 0.05. Nevertheless, it is necessary to slightly modify the climate zones of Koppen–Geiger initial classification for a better explanation of the atmospheric attenuation. This climate zones modification can be considered as an additional result.
Enhancement of photorefraction in whispering gallery mode resonators

We report on the study of photorefractive properties of as-grown nominally pure lithium niobate and tantalate crystals using whispering gallery mode (WGM) resonators. The photorefractive effect manifests itself as a dynamic modification of the spectrum of the resonator, which includes the relative motion of various families of WGMs in the frequency space. We have observed the effect in near $(780\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ as well as in the far $(1550\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ infrared. Our experiments support the conclusion that the photorefractivity does not have a distinct red boundary. We show that the maximum saturated refractive index change in the infrared is of the same order of magnitude as in the visible light.
Hepatic falciform artery

The hepatic falciform artery is an occasional terminal branch of the left or middle hepatic artery, and may provide an uncommon but important collateral route when the principal visceral arteries are occluded.
ANOMALOUS BEHAVIOURS OF PROTACTINIUM IN THE ACID-LEACHING EXPERIMENTS ON PITCHBLENDE

A series of leaching experiments with H2O, HCl, HNO2 and HF were carried out on a sample of pitchblende from Africa. Anomalously high231Pa/235U ratios, which were not accompanied by similar enhancements of234U/238U and235U/238U ratios, were observed in some uranium fractions. The observed231Pa/235U ratios varied between the values of 0.035±0.005 and 2,000±300 (Ci/Ci). These results are interpreted as due, primarily, to the difference in the chemical properties of protactinium and uranium, rather than to the alpha-recoil effects.
MAC-layer anycasting in ad hoc networks

A wireless ad hoc network is formed by a group of wireless hosts, without the use of any infrastructure. To enable communication, hosts cooperate among themselves to forward packets on behalf of each other. A key challenge in ad hoc networks lies in designing efficient routing strategies. While several routing protocols have been proposed, most of them aim to select one optimal route between the source and destination. The MAC layer at each intermediate node is then required to forward packets to the next downstream node on that route. We argue that choosing a single optimal route at the network layer may not be sufficient. Knowledge of short-term channel conditions at the MAC layer can play an important role in improving end-to-end performance. Instantaneous interference, channel contention, power constraints and other considerations may be taken into account along with the network layer's long-term view. This paper proposes MAC layer anycasting- a forwarding strategy that combines the guidelines from the network layer, with MAC layer knowledge of the local channel. We describe some applications of MAC-layer anycasting, and discuss the performance related tradeoffs.
On intentional introduction of stiffness nonlinearities for energy harvesting under white Gaussian excitations

A significant body of the open literature on vibratory energy harvesting is currently focused on the concept of purposeful inclusion of stiffness nonlinearities for broadband transduction. When compared to their linear resonant counterparts, nonlinear energy harvesters have a wider steady-state frequency bandwidth, leading to the idea that they can be utilized to improve performance especially in random and non-stationary vibratory environments. To further investigate this common belief, this paper studies the response of vibratory energy harvesters to white Gaussian excitations. Both mono- and bi-stable piezoelectric Duffing-type harvesters are considered. The Fokker–Plank–Kolmogorov equation governing the evolution of the system’s transition probability density function is formulated and used to generate the moment differential equations governing the response statistics. The moment equations are then closed using a fourth-order cumulant-neglect closure scheme and the relevant steady-state response statistics are obtained. It is demonstrated that the energy harvester’s time constant ratio, i.e., the ratio between the nominal period of the mechanical subsystem and the time constant of the harvesting circuit, plays a critical role in characterizing the performance of nonlinear harvesters in a random environment. When the time constant ratio is large, stiffness-type nonlinearities have very little influence on the voltage response. In such a case, no matter how the potential function of the harvester is altered, it does not affect the average output power of the device. When the time constant ratio is small, the influence of the nonlinearity on the voltage output becomes more prevalent. In this case, a Duffing-type mono-stable harvester can never outperform its linear counterpart. A bi-stable harvester, on the other hand, can outperform a linear harvester only when it is designed with the proper potential energy function based on the known noise intensity of the excitation. Such conclusions hold for harvesters with nonlinearities appearing in the restoring force.
Metabolism of Pre-Messenger RNA Splicing Cofactors: Modification of U6 RNA Is Dependent on Its Interaction with U4 RNA

The requirements for the formation of pseudouridine (psi) in U4 and U6 RNAs, cofactors in the splicing of pre-messenger RNA, were investigated in vitro using HeLa nuclear (NE) and cytoplasmic (S100) extracts. Maximal psi formation for both RNAs was extract order-dependent. Maximal psi formation in U4 RNA required incubation in S100 followed by the addition of NE, paralleling the in vivo maturation pathway of U4 RNA. In contrast, maximal formation of psi in U6 RNA required incubation in NE followed by the addition of S100 extract. Since U6 RNA does not exit the nucleus in vivo the contribution of S100 was investigated. In experiments where the extracts were treated with micrococcal nuclease to digest endogenous snRNAs, the efficient formation of psi in U6 RNA was dependent on the presence of U4 RNA, but not in U5 RNA or tRNA. When mutant U4 RNAs that inhibit or strengthen the interaction between U4 RNA, and U6 RNA were substituted for wild-type U4 RNA, the results confirmed the need for the interaction between these two RNAs for psi formation in U6 RNA. U6 RNA isolated from glycerol gradients after incubation in extracts had four times as much psi when associated with U4 RNA.
Vitamin A programme in Assam probably caused hysteria

EDITOR—Did the recent campaign to distribute vitamin A in Assam, India, cause an epidemic of illness or hysteria? The public health science underlying vitamin A prophylaxis and the reports that emerged after the same-day dosing of some 2.5 million preschool children point to hysteria. Firstly, did vitamin A kill a child the day after dosing, and up to 13 children the next week, as claimed (overdosage by a new, larger delivery cup is being cited as the cause)?1 Almost certainly …
Three-gene molecular diagnostic model for thyroid cancer

Background: The preoperative diagnosis of thyroid nodules primarily depends upon fine needle aspiration (FNA) cytology. However, up to 25% of FNA samples have associated “suspicious or indeterminate”, but not diagnostic cytologic reports, resulting in difficulty deciding appropriate clinical management for these patients. We hypothesize that the use of molecular markers as an adjunct to FNA cytology can improve the distinction of benign from malignant nodules that have associated suspicious or indeterminate cytology. Methods: Using microarray analysis, we previously identified and reported on 75 genes useful in the distinction of benign versus malignant thyroid nodules. In the present study, we have further validated the expression of 14 of these markers in a large number of thyroid samples by immunohistochemistry (IHC) analysis of 154 thyroid tumors and quantitative real-time RT-PCR (QRT-PCR) analysis of 95 FNA samples. Of the 154 tumors analyzed by IHC, 44 samples (29%) had associated suspicious or inde...
Components of Supervisors’ Ratings of Therapists’ Skillfulness

A questionnaire was developed to assess the skillfulness of therapists from the perspective of the supervisor. This supervisor report yielded two scores: one for psychotherapeutic techniques and one for the educational alliance. These scores had high internal consistency and were relatively independent of one another. Ratings of proficiency in psychotherapeutic techniques accounted for 54% of the variance in supervisors’ rating? of global skillfulness; educational alliance contributed an additional 12%. Compared with other supervisors, those who espoused self psychology based more of their appraisal of skill fulness on the trainee’s use of the supervisory relationship.
Evolutionary differentiation in the Neotropical montane region: Molecular phylogenetics and phylogeography of Buarremon brush-finches (Aves, Emberizidae)

Studies on Neotropical phylogeography have largely focused on lowland organisms. Because lowland and highland biotas have different histories and are likely affected by different processes influencing population differentiation, understanding Neotropical diversification requires detailed studies on montane taxa. We present the most comprehensive analysis of population differentiation conducted so far on a widespread group of Neotropical montane organisms, focusing on the evolutionary relationships and phylogeography of Buarremon brush-finches (Aves: Emberizidae) in montane areas from Mexico through Argentina. Sequences of mitochondrial and nuclear genes demonstrate that Buarremon is not monophyletic with respect to Arremon and Lysurus. Genetic structure revealed by mtDNA is strong in both B. brunneinucha and B. torquatus. Gene genealogies and nucleotide diversity indicate that B. brunneinucha originated in Mexico and later expanded to South America, where it followed one colonization route through the east, and one through the west of the continent. Differentiation among populations of B. torquatus was substantial, reaching 8% uncorrected sequence divergence within South America. Relationships among major lineages of B. torquatus were not fully resolved owing to rapid differentiation, but the occurrence of closely related taxa in distant locations suggests a complex history of diversification. Some Colombian populations of B. brunneinucha have affinities with populations from Venezuela and the East Andean slope of Ecuador and Peru, and others with those from the Pacific slope of Ecuador. Moreover, five divergent lineages of B. torquatus occur within Colombia, highlighting the importance of dense sampling in northwest South America for studies on diversification of widespread Neotropical lineages.
Effect of Small-World Networks on Epidemic Propagation and Intervention

The small-world network, characterized by special structural properties of high connectivity and clustering, is one of the highlights in recent advances in network science and has the potential to model a variety of social contact networks. In an attempt to better understand how these structural properties of small-world networks affect epidemic propagation and intervention, this article uses an agent-based approach to investigate the interplay between an epidemic process and its underlying network structure. Small-world networks are derived from a network ‘‘rewiring’’ process, which readjusts edges in a completely regular two-dimensional network by different rewiring probabilities (0–1) to produce a spectrum of modified networks on which an agent-based simulation of epidemic propagation can be conducted. A comparison of simulated epidemics discloses the effect of small-world networks on epidemic propagation as well as the effectiveness of different intervention strategies, including mass vaccination, acquaintance vaccination, targeted vaccination, and contact tracing. Epidemics taking place on small-world networks tend to reach large-scale epidemic peaks within a short time period. Among the four intervention strategies tested, only one strategy—the targeted vaccination—proves to be effective for containing epidemics, a finding supported by a simulation of the severe acute respiratory syndrome epidemic in a large-scale realistic social contact network in Portland, OR.
Analytical solutions for the electromagnetic fields of flattened and annular Gaussian laser modes. III. Arbitrary length pulses and spot sizes

In the first two parts of this study, the electromagnetic field components were derived for infinitely long, flattened Gaussian laser beams [J. Opt. Soc. Am. B23, 2157 and J. Opt. Soc. Am. B23, 2166 (2006)]. These results are now extended without approximation to allow for finite laser pulses having an arbitrary duration beginning with the standard Gaussian beam profile and then generalizing these results to a flattened Gaussian. The resulting models thus allow for all pulse durations and spot sizes from infinite, paraxial beams to single-cycle, wavelength-size spots, with a savings of more than 2 orders of magnitude in computation time. Pulses having fewer than ten cycles exhibit significant modification from the monochromatic fields as a result of the finite bandwidth. Specifically, the energy in the focus is shown to decrease from the theoretical value of 86.5% to as low as 72.2% for a single-cycle pulse.
Quality is a verb: the operationalization of data quality in a citizen science community

Citizen science is becoming more valuable as a potential source of environmental data. Involving citizens in data collection has the added educational benefits of increased scientific awareness and local ownership of environmental concerns. However, a common concern among domain experts is the presumed lower quality of data submitted by volunteers. In this paper, we explore data quality assurance practices in River Watch, a community-based monitoring program in the Red River basin. We investigate how the participants in River Watch understand and prioritize data quality concerns. We found that data quality in River Watch is primarily maintained through universal adherence to standard operating procedures, but there remain areas where technological intervention may help. We also found that rigorous data quality assurance practices appear to enhance rather than hinder the educational goals of the program. We draw implications for the design of quality assurance mechanisms for River Watch and other citizen science projects.
Dosimetric Comparisons of Supine Versus Prone Radiation: Implications on Normal Tissue Toxicity

position used for treatment. Relevant volumes contoured included the post-operative tumor bed (CTV), the ipsilateral breast volume (IBV), the heart, and the lungs. The PTV was defined as CTV 1 cm. The residual breast volume (RBV) was defined as the IBV PTV. A dose of 40.5 Gy in 15 fractions was prescribed to the IBV. An additional 0.5 Gy was delivered concomitantly to the PTV for a total dose of 48 Gy. The dose was determined by radiobiological modeling of BED, to match tumor control and risk of late effects of a standard schedule of 46 Gy to the whole breast plus a sequential boost dose of 14 Gy to the tumor bed. A value for tumor alpha/beta 4 was used and the impact of cell proliferation during the course of treatment was taken into account. For each patient accrued to the study blood was collected for radiation genomic studies, to explore markers predictive of late breast complications (fibrosis, teleangectasia).
The level of insulin receptor tyrosine kinase activity modulates the activities of phosphatidylinositol 3-kinase, microtubule-associated protein, and S6 kinases.

The role of insulin receptor tyrosine kinase activity in stimulation of intracellular enzymes linked to insulin action [phosphatidylinositol 3-kinase (PtdIns 3-kinase), microtubule-associated protein (MAP) kinase, and S6 kinases] was studied in Chinese hamster ovary cells which overexpress wild type human insulin receptors, receptors with reduced kinase activity due to substitution of Phe for Tyr1146 (single-Phe), Tyr1150,1151 (double-Phe), and Tyr1146,1150,1151 (triple-Phe), or kinase-inactive receptors with a substitution of Ala for Lys1018 in the ATP binding site (A1018). We have previously shown that receptor autophosphorylation and kinase activity of these mutants were reduced by approximately 50, 65, 85, and 100%, respectively. Glycogen and DNA synthesis parallel the level of receptor autophosphorylation and kinase activity; however, receptor serine and threonine phosphorylation was independent of receptor tyrosine kinase activity and receptor internalization was completely dependent on maximal rece...
Cracking of Laminates Subjected to Biaxial Tensile Stresses

During the processing of laminar ceramic, biaxial residual stresses can arise due to differential thermal contraction between unlike layers. A tensile stress can cause preexisting flaws to extend across the layer and into the adjacent layers and then tunnel until they meet either another crack or a free surface. A previous analysis has shown that for a given residual stress there is a critical layer thickness, below which no tunnel cracks will exist, regardless of initial flaw size. Here, the previous analysis was modified to take into account the crack extension into adjacent layers. To determine the validity of the analysis, laminates composed of alternating layers of zirconia and alumina/zirconia were fabricated by a sequential centrifugation technique. The composition of the alumina/zirconia layer was varied to change the biaxial, tensile stresses in the zirconia layer. Observations were then made to determine the critical layer thickness for tunnel cracks and their extension into the adjacent layers. These observations were compared to the theoretical predictions.
Patterns of hybridization and introgression between invasive Ulmus pumila (Ulmaceae) and native U. rubra

Natural hybridization between introduced species and their native congeners occurs frequently and can create serious conservation concerns. Ulmus pumila (Siberian elm) is an introduced Asian elm species that has naturalized in the United States and is now considered invasive in 41 states. Red elm (U. rubra), a native to the eastern United States, often occurs in sympatry with Siberian elm, and the two species are thought to hybridize. Here, we genetically characterized reference populations of the two elm species to identify species-specific microsatellite alleles. These markers were used to classify individuals in putative hybrid zones as parental species or hybrids, assess the extent of hybridization, and track patterns of introgression. We identified nine U. rubra, 32 U. pumila, and 51 hybrid individuals in our hybrid zones. Of the 51 hybrids, 35 were classified as first-generation hybrids and 16 as backcrosses. The majority of the backcrosses (88%) were introgressed toward U. pumila. Our classification of genotypes was consistent whether we used manual classification, principal coordinate analyses or Bayesian clustering. We observed greater genetic diversity and new combination of alleles in the hybrids. Our study indicates widespread hybridization between U. pumila and U. rubra and an asymmetric pattern of introgression toward U. pumila.
Identifying Health Disparities and Social Inequities Affecting Childbearing Women and Infants

This article presents health disparities and social inequities that may underlie adverse outcomes for childbearing women and infants in the United States. It also presents Internet-accessible databases that nurses can use to assess maternal and infant health disparities at a national or state level. Such assessments are basic to planning programs to address gaps in health care and advocating for practice and policy changes to improve the health care of childbearing women and infants.
Psychiatric genetic research at the National Institute of Mental Health

For some time it has been known through the results of family, twin, and adoption studies that heredity appears to play a significant causal role in many mental disorders, including schizophrenia, bipolar disorder, and other mood disorders, Alzheimer's Disease, panic disorder, obsessive compulsive disorder, autism, dyslexia, and Tourette's Syndrome. The precise patterns of inheritance of these complex disorders have not been determined, nor have the relevant genes been localized or cloned. Because the genetics are complex and because there is also clearly an environmental contribution to behavior, we expect the analysis of the genetics of mental illness to be arduous, and not quickly resolved. There are several compelling reasons to continue to focus our attention on uncovering the genetic factors for severe mental illness. Prominent among these are the implications for better treatment of mental disorders. The National Institute of Mental Health supports a wide range of studies on psychiatric genetic research.
Survivor: Is There an Optimal Country Size?

Contemporary manifestations of international integration and national disintegration have stimulated speculation on the optimal size of a country. Economic theories focus on efficient resource allocation, and empirical work on partial equilibrium tests correlating size with variables (limited by data availability to recent times) selected from theoretical models of optimal size. This article questions the assumption that there is an optimal size, offering a test using data covering 500 years. The existence of an optimum, determined by efficiency or other goals, will be revealed by a size category generating an increasing proportion of world income, as more states move into that category. The results of this “survivor” test do not indicate the emergence of an optimal country size, despite data limitations that prevent cross-sectional analysis over a long time period. The absence of evolution toward optimal size suggests alternative directions in the research on country size.
A population pharmacokinetic (PK) and pharmacodynamic (PD) analysis of cinacalcet HCL in renal-dialysis patients with secondary hyperparathyroidism (HPT)

The objective of this investigation was to develop a PK/PD model for cinacalcet MCI in renal-dialysis patients with secondary HPT. Parathyroid hormone (PTH) is regulated by a parathyroid cell-surface calcium-sensing receptor. The free base of cinacalcet HCl (cinacalcet) acts on this receptor and inhibits PTH secretion. In this analysis, PK and PTH observations from 218 patients were pooled from 6 clinical studies and analyzed using NONMEM. One study was a fixed-dose trial with intensive PK/PD sampling. The remaining 5 studies used limited sampling, and patients were dose-titrated from 30 mg to a possible max dose of 180 mg. The PK of cinacalcet was described by a 2-compartment model with delayed first-order absorption. The estimated population mean oral clearance (CL/F) was 234±19 L/h. Age, body weight, BMI did not affect the PK of cinacalcet. From a follow-up analysis, concomitant vitamin D therapy had no apparent effect on cinacalcet PK. Sex and smoking had modest, although clinically insignificant effects on CL/F. Because cinacalcet is titrated for each patient, demographics-based dose adjustments are unnecessary. The suppression of PTH by cinacalcet was described by an Imax PD model. The estimated maximum proportion of PTH suppression by cinacalcet (Imax) was 1.0, suggesting high concentrations of cinacalcet may completely Inhibit PTH production in these patients. The estimated cinacalcet concentration associated with 50% PTH suppression (IC50) was 10.6±1.2 ng/mL. Clinical Pharmacology & Therapeutics (2004) 75, P62–P62; doi: 10.1016/j.clpt.2003.11.236
Management of gunshot wounds of the foot

Civilian injuries due to firearms are increasing in the United States (1,2). Criminal violence has sharply increased the incidence of high-velocity wounds in civilian practice (1). Gunshot wounds of the foot represent a special circumstance of the broad spectrum of firearm injuries. A fundamental understanding of the wounding mechanisms involving energy transfer is paramount to effective management. Furthermore, adequate care of the gunshot wound of the foot requires careful consideration of its unique anatomical constraints and of the biomechanical issues regarding weight-bearing and the gait cycle to ensure functional recovery. The purpose of this article is to review an approach to the care of gunshot wounds of the foot based on the literature and the authors' experience treating these injuries at San Francisco General Hospital.
Erythropoietin modulation of intracellular calcium: a role for tyrosine phosphorylation

Abstract We have reported that erythropoietin induces a dose-dependent increase in cytosolic calcium ([Ca i ]) in single human peripheral blood BFU-E derived erythroblasts which is specific for stage of differentiation and that this increase is modulated by erythropoietin through an ion channel permeable to Ca 2+ . Here, the role of protein phosphorylation in the increase in intracellular free calcium [Ca i ] stimulated by erythropoietin was studied with digital video imaging. Preincubation of day 10 erythroblasts with a broad inhibitor of serine/threonine and tyrosine kinases, staurosporine (100 nM), blocked the increase in [Ca i ] over 20 min following erythropoietin stimulation. However, erythropoietin-induced calcium influx was unaffected by preincubation of cells with specific inhibitions of protein kinase C (calphostin C) or the cAMP- or cGMP-dependent kinases (KT 5720, HA 1004), and [Ca i ] did not increase following stimulation with phorbol 12-myristate 13-acetate (PMA) or dibutyryl cAMP. These results suggest that neither protein kinase C nor protein kinase A mediate the erythropoietin-induced [Ca i ] increase. In contrast, preincubation with genistein, a tyrosine kinase inhibitor, blocked the erythropoietin induced increase in [Ca i ]. To further study calcium entry in erythroblasts, we determined mastoparan, a peptide from wasp venom, induced a dose-dependent rise in [Ca i ] in erythroblasts which required external calcium. Stimulation of erythroid precursors with 10 μM mastoparan resulted in an increase in [Ca i ] from 52 ± 3 nM to 214 ± 36 nM which peaked at 20 min. The mastoparan-induced [Ca i ] increase was also dependent on tyrosine phosphorylation since it was blocked by preincubation with genistein. These results demonstrate that both erythropoietin and mastoparan stimulate calcium entry by a mechanism which has a genistein sensitive step and suggest that tyrosine kinase activation is required for the rise in [Ca i ] to occur.
STIMULATION OF PIGEON PITUITARY PROLACTIN RELEASE BY PIGEON HYPOTHALAMIC EXTRACT IN VITRO.

Previous studies from this laboratory suggested that the mechanism for control of prolactin release by the avian pituitary was different from that present in mammals. The effects of pigeon hypothalamic extracts on release of prolactin by the pigeon pituitary were determined when incubated together at 37 C for 2 or 4 hr. The effects of rat or pigeon hypothalamic extracts on release of prolactin by the pituitary of the other species were also tested. Extract equivalent to 1 hypothalamus from a parent pigeon, sacrificed on the day young were hatched, increased prolactin release 2- to 4-fold from each pituitary of 4- to 6-week-old pigeons during a 4-hr incubation period. Slight stimulatory activity was also found in hypothalamic extracts from 4- to 6-week-old pigeons, but at the dose level tested (2 hypothalami/pituitary) they did not elicit a statistically significant increase in prolactin release. Hypothalamic extracts from rats or pigeons had no effect on release of prolactin by the pituitaries of the othe...
Digestive bioavailability to a deposit feeder (Arenicola marina) of polycyclic aromatic hydrocarbons associated with anthropogenic particles

Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola marina), we determined the digestive bioavailability of PAHs from fly ashes, coal dusts, diesel soots, tire tread materials, and urban particulates. We found that gut fluids solubilize significant concentrations of PAHs from two tire treads, two diesel soots, and the urban particulates. However, PAHs in fly ashes and coal dusts were not available to the digestive agents in gut fluid. Potential digestive exposure to PAHs is much greater than that predicted to be available from these materials using equilibrium partitioning theory (EqP). Amending an already-contaminated sediment with fly ash decreased phenanthrene solubilization by gut fluid. In contrast, addition of tire tread to the sediment resulted in increased solubilization of four PAHs by gut fluid. Therefore, addition of certain types of anthropogenic particles to sediments may result in an increase in bioavailable PAHs rather than a net decrease, as predicted by EqP. Difficulty in predicting the amount of change due to amendment may be due to interactions occurring among the mixture of compounds solubilized by gut fluid.
Genetic and Physiological Responses of Bifidobacterium animalis subsp. lactis to Hydrogen Peroxide Stress

Consumer interest in probiotic bifidobacteria is increasing, but industry efforts to secure high cell viability in foods is undermined by these anaerobes' sensitivity to oxidative stress. To address this limitation, we investigated genetic and physiological responses of two fully sequenced Bifidobacterium animalis subsp. lactis strains, BL-04 and DSM 10140, to hydrogen peroxide (H₂O₂) stress. Although the genome sequences for these strains are highly clonal, prior work showed that they differ in both intrinsic and inducible H₂O₂ resistance. Transcriptome analysis of early-stationary-phase cells exposed to a sublethal H₂O₂ concentration detected significant (P < 0.05) changes in expression of 138 genes in strain BL-04 after 5 min and 27 genes after 20 min. Surprisingly, no significant changes in gene expression were detected in DSM 10140 at either time. Genomic data suggested that differences in H₂O₂ stress resistance might be due to a mutation in a BL-04 gene encoding long-chain fatty acid coenzyme A (CoA) ligase. To explore this possibility, membrane fatty acids were isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). Results confirmed that the strains had significantly different lipid profiles: the BL-04 membrane contained higher percentages of C(14:0) and C(16:0) and lower percentages of C(18:1n9). Alteration of the DSM 10140 membrane lipid composition using modified growth medium to more closely mimic that of BL-04 yielded cells that showed increased intrinsic resistance to lethal H₂O₂ challenge but did not display an inducible H₂O₂ stress response. The results show that deliberate stress induction or membrane lipid modification can be employed to significantly improve H₂O₂ resistance in B. animalis subsp. lactis strains.
Tunable and Broadband Plasmonic Absorption via Dispersible Nanoantennas with Sub‐10 nm Gaps

Plasmonic nanoparticles have traditionally been associated with relatively narrow absorption profiles. But, for many of the most exciting potential applications for these particles, such as solar energy applications, broadband absorption is desirable. By utilizing on-wire lithography, nanostructures which absorb light through the visible and near-IR portions of the electromagnetic spectrum can be synthesized.
Estimates of circulation and gait change based on a three-dimensional kinematic analysis of flight in cockatiels (Nymphicus hollandicus) and ringed turtle-doves (Streptopelia risoria)

SUMMARY Birds and bats are known to employ two different gaits in flapping flight, a vortex-ring gait in slow flight and a continuous-vortex gait in fast flight. We studied the use of these gaits over a wide range of speeds (1-17 ms -1 ) and transitions between gaits in cockatiels ( Nymphicus hollandicus ) and ringed turtle-doves ( Streptopelia risoria ) trained to fly in a recently built, variable-speed wind tunnel. Gait use was investigated via a combination of three-dimensional kinematics and quasi-steady aerodynamic modeling of bound circulation on the distal and proximal portions of the wing. Estimates of lift from our circulation model were sufficient to support body weight at all but the slowest speeds (1 and 3 ms -1 ). From comparisons of aerodynamic impulse derived from our circulation analysis with the impulse estimated from whole-body acceleration, it appeared that our quasi-steady aerodynamic analysis was most accurate at intermediate speeds (5-11 ms -1 ). Despite differences in wing shape and wing loading, both species shifted from a vortex-ring to a continuous-vortex gait at 7 ms -1 . We found that the shift from a vortex-ring to a continuous-vortex gait (i) was associated with a phase delay in the peak angle of attack of the proximal wing section from downstroke into upstroke and (ii) depended on sufficient forward velocity to provide airflow over the wing during the upstroke similar to that during the downstroke. Our kinematic estimates indicated significant variation in the magnitude of circulation over the course the wingbeat cycle when either species used a continuous-vortex gait. This variation was great enough to suggest that both species shifted to a ladder-wake gait as they approached the maximum flight speed (cockatiels 15 ms -1 , doves 17 ms -1 ) that they would sustain in the wind tunnel. This shift in flight gait appeared to reflect the need to minimize drag and produce forward thrust in order to fly at high speed. The ladder-wake gait was also employed in forward and vertical acceleration at medium and fast flight speeds.