cssi/SciSciGPT-SciSciNet huggingface dataset:
An incidence algebra for t -designs with automorphisms

Abstract A t-design or generalized Steiner systemS(λ; t, k, υ) is a pair (X, B) with a υ-set X of points and a family B of k-subsets of X called blocks such that, each block has k points and any t points are contained in exactly λ blocks. An automorphism of (X, B) is a permutation of X which preserves B. In this paper the algebra of matrices, whose rows and columns are indexed by the members of P(X), that are invariant under the natural action of a group G ⩽Sym(X) is introduced. An epimorphism τ from this algebra onto the matrices whose rows and columns are indexed by the orbits of G acting on P(X) is discovered. This mapping carries the matrices of Wilson onto the matrices of Kramer and Mesner and therefore can be used to generalize the t-design inequalities of Fisher, Wilson, and Ray-Chaudhuri. A conjecture of Earl Kramer is settled and an elementary proof of a theorem of Livingstone and Wagner is presented.
CRISPR/Cas9 Allows Efficient and Complete Knock-In of a Destabilization Domain-Tagged Essential Protein in a Human Cell Line, Allowing Rapid Knockdown of Protein Function

Although modulation of protein levels is an important tool for study of protein function, it is difficult or impossible to knockdown or knockout genes that are critical for cell growth or viability. For such genes, a conditional knockdown approach would be valuable. The FKBP protein-based destabilization domain (DD)-tagging approach, which confers instability to the tagged protein in the absence of the compound Shield-1, has been shown to provide rapid control of protein levels determined by Shield-1 concentration. Although a strategy to knock-in DD-tagged protein at the endogenous loci has been employed in certain parasite studies, partly due to the relative ease of knock-in as a result of their mostly haploid lifecycles, this strategy has not been demonstrated in diploid or hyperploid mammalian cells due to the relative difficulty of achieving complete knock-in in all alleles. The recent advent of CRISPR/Cas9 homing endonuclease-mediated targeted genome cleavage has been shown to allow highly efficient homologous recombination at the targeted locus. We therefore assessed the feasibility of using CRISPR/Cas9 to achieve complete knock-in to DD-tag the essential gene Treacher Collins-Franceschetti syndrome 1 (TCOF1) in human 293T cells. Using a double antibiotic selection strategy to select clones with at least two knock-in alleles, we obtained numerous complete knock-in clones within three weeks of initial transfection. DD-TCOF1 expression in the knock-in cells was Shield-1 concentration-dependent, and removal of Shield-1 resulted in destabilization of DD-TCOF1 over the course of hours. We further confirmed that the tagged TCOF1 retained the nucleolar localization of the wild-type untagged protein, and that destabilization of DD-TCOF1 resulted in impaired cell growth, as expected for a gene implicated in ribosome biogenesis. CRISPR/Cas9-mediated homologous recombination to completely knock-in a DD tag likely represents a generalizable and efficient strategy to achieve rapid modulation of protein levels in mammalian cells.
Leveling the Playing Field: The Development of a Distance Education Program in Rehabilitation Counseling.

This article describes the curriculum design and development of an online Master's degree program in Rehabilitation Counseling at the University of South Carolina. The use of Bloom's Taxonomy as a method for selecting distance education techniques and teaching methods to ensure equivalency of the educational experience to traditional classroom teaching is described. The author presents tables to demonstrate the cognitive competencies, traditional and distance education methods, and use of synchronous and asynchronous methods in reaching desired educational objectives. This process has resulted in the creation of a program that offers distance education options, traditional classroom options, or a blend of approaches. The menu of options has met the unique learning needs of all students and has offered students with disabilities a level playing field on which to build rehabilitation counseling competencies.
Myosin heavy chain expression in embryonic cardiac cell cultures.

Abstract Chick embryonic heart cell isolates and monolayer cultures were prepared from atria and ventricles at selected stages of cardiac development. The cardiac myocytes were assayed for myosin heavy chain (MHC) content using monoclonal antibodies (McAbs) specific in the heart for atrial (B-1), ventricular (ALD-19), or conductive system (ALD-58) isoforms. Using immunofluorescence microscopy or radioimmunoassay, MHC accumulation was measured before plating and at 48 hr or 7 days in culture. Reproducible changes in MHC antigenicity were observed by 7 days in both atrial and ventricular cultures. The changes were stage dependent and tissue specific but generally resulted in a decreased reactivity with the tissue specific MHC McAbs. In addition, the isoform recognized by ALD-58, characteristic of the conductive system cells in vivo , was never present in cultured myocytes. These results indicate the MHC isoforms produced in vivo may be replaced in monolayer cultures by an isoform(s) not recognized by our tissue specific MHC McAbs. This suggests that the intrinsic program of cardiac myogenesis, within cardiac myocytes, may not be sufficient to establish and maintain differential expression of tissue specific MHC in monolayer cell culture.
Temperatures in a convecting upper mantle

Abstract Numerical computations show that in a convecting upper mantle the temperature rises rapidly to about 1000°C near a depth of 100 km; below this depth it stays essentially constant until about 350 km. This result agrees with data obtained from the olivine-spinel phase change.
On interlistening and the idea of dialogue

Among the many analytical categories bequeathed by linguistics to the study of dialogue, some inadvertently conceal more than they reveal. In addition to instantiating such fictions as speaker and ...
MUCOPOLYSACCHARIDE HISTOCHEMISTRY OF RAT TOOTH GERMS.

The histochemical distribution and localization of acid mucopolysaccharides and glycoproteins have been studied in rat tooth germs and lower joints. After fixation, sections were stained with PAS, alcian blue-PAS, colloidal iron, colloidal iron-PAS, colloidal iron-Feulgen, azure A and safranin O. Prior to staining, sections were incubated in hyaluronidase, pepsin and papain. A 2 hour incubation in pepsin greatly enhanced AB or CI basophilia in the stellate reticulum and the enamel-dentinal junction. These findings demonstrated that some acidic radicals of the polysaccharides are partially blocked by basic proteins. Hyaluronidase did not completely destroy the alcian blue or colloidal iron positive material whereas azure A metachromasia was completely removed. These results indicated that AB and/or CI stained substrates different from those revealed by azure A.
Contemporary threats and air pollution

It is now well understood that air pollution produces significant adverse health effects in the general public and over the past 60 years, there have been on-going efforts to reduce the emitted pollutants and their resulting health effects. There are now shifting patterns of industrialization with many heavily polluting industries moving from developed countries with increasingly stringent air quality standards to the developing world. However, even in decreasing concentrations of pollutants, health effects remain important possibly as a result of changes in the nature of the pollutants as new chemicals are produced and as other causes of mortality and morbidity are reduced. In addition, there is now the potential for deliberate introduction of toxic air pollutants by local armed conflicts and terrorists. Thus, there are new challenges to understand the role of the atmospheric environment on public health in this time of changing economic and demographic conditions overlaid with the willingness to indirectly attack governments and other established entities through direct attacks on the general public.
The Black Instructor: An Essential Dimension to the Content and Structure of the Social Work Curriculum

Abstract How can the use of minority faculty be more than visual tokenism for both minority and nonminority students? Is there a role for minority faculty in developing curriculum and in faculty development? In answer to these questions, this paper describes the use one faculty member has made of his Blackness as an essential dimension to the content and structure of the social work curriculum, and its impact on students' professional development. The attitudinal aspects of racism are explored in the context of the relationship of students and the Black instructor, resulting in the conceptualization of racism as a practice issue.
Assessing Mangrove Above-Ground Biomass and Structure using Terrestrial Laser Scanning: A Case Study in the Everglades National Park

Mangroves are among the ecosystems with the highest potential for carbon sequestration and storage. In these ecosystems and others above-ground biomass (AGB) is often used to estimate above-ground carbon content. We used a Leica-ScanStation-C10 Terrestrial Laser Scanner (TLS) to estimate the volume and AGB of 40 mangrove trees distributed in three different mangrove sites located along Shark River Slough (SRS), in the western Everglades National Park. To estimate the volumetric shape of mangroves, we modeled stems as tapered geometrical surfaces called frustums of paraboloids and prop roots (Rhizophora mangle) as toroids and cylinders. AGB was estimated by multiplying the TLS-derived volume by wood specific density. Our TLS method for the SRS sites resulted in AGB estimates in the range of: 3.9 ± 0.4 to 31.3 ± 3.4 kg per tree in the short mangrove (<5 m) site, 27.4 ± 3.0 to 119.1 ± 12.9 kg per tree in the intermediate (<13 m) site and 52.1 ± 6.7 to 1756.5 ± 189.7 kg per tree in the tall (13–23 m) mangrove site. Our quantitative results: (1) enabled us to develop site-specific allometric relationships for tree diameter and AGB and (2) suggested that TLS is a promising alternative to destructive sampling.
Evaluation of irreversible JPEG compression for a clinical ultrasound practice.

A prior ultrasound study indicated that images with low to moderate levels of JPEG and wavelet compression were acceptable for diagnostic purposes. The purpose of this study is to validate this prior finding using the Joint Photographic Experts Group (JPEG) baseline compression algorithm, at a compression ratio of approximately 10:1, on a sufficiently large number of grayscale and color ultrasound images to attain a statistically significant result. The practical goal of this study is to determine if it is feasible for radiologists to use irreversibly compressed images as an integral part of the day to day ultrasound practice (ie, perform primary diagnosis with, and store irreversibly compressed images in the ultrasound PACS archive). In this study, 5 Radiologists were asked to review 300 grayscale and color static ultrasound images selected from 4 major anatomic groups. Each image was compressed and decompressed using the JPEG baseline compression algorithm at a fixed quality factor resulting in an average compression ratio of approximately 9:1. The images were presented in pairs (original and compressed) in a blinded fashion on a PACS workstation in the ultrasound reading areas, and radiologists were asked to pick which image they preferred in terms of diagnostic utility and their degree of certainty (on a scale from 7 to 4). Of the 1,499 total readings, 50.17% (95% confidence intervals at 47.6%, and 52.7%) indicated a preference for the original image in the pair, and 49.83% (95% confidence intervals at 47.3%, and 52.0%) indicated a preference for the compressed image. These findings led the authors to conclude that static color and gray-scale ultrasound images compressed with JPEG at approximately 9:1 are statistically indistinguishable from the originals for primary diagnostic purposes. Based on the authors laboratory experience with compression and the results of this and other prior studies JPEG compression is now being applied to all ultrasound images in the authors radiology practice before reading. No image quality-related issues have been encountered after 12 months of operation (approximately 48,000 examinations).
Fracture behaviour of interleaved fiber-resin composites

Abstract Interleaving, the technique of inserting a tough material into the composite laminate as extra interlaminar layers, has been used successfully to enhance the damage tolerance of brittle composites. Both carboxyl-terminated butadiene acrylonitrile (CTBN) and polyurethane (PU) were used to modify various epoxy resins. These modified epoxy resins were then chosen as interleaf materials for toughening graphite/epoxy composites. The effects of adding a thin interleaf phase on the microstructure and the fracture resistance of the resulting laminates were investigated. The results obtained from double cantilever beam (DCB) tests and end notched flexure (ENF) tests demonstrate that the tensile opening mode (Mode I) and the shear mode (Mode II) critical strain energy release rates of a graphite/epoxy laminate can be improved considerably by the technique of interleaving. The damage tolerance of interleaved composites, as assessed by the impact fatigue tests, is much greater than that of the control sample. The critical stress intensity factor, K lc , of interleaved materials was also measured by use of compact tension specimens and was correlated with the mechanical properties of the corresponding interleaved composites.
Variability in oleic and linoleic acid contents of safflower oil

Variations in iodine value in safflower oil from 87 to 149 were based mostly on differences in levels of oleic and linoleic acid. Levels of oleic acid varied from 8.9 to 86.8%, and linoleic acid from 8.7 to 84.6%. Excepting two samples from Israel, which had 10.8 and 11.2% stearic acid, there was a close positive correlation between iodine value and linoleic acid and a close negative correlation between iodine value and oleic acid.
Sex differences in domain-specific depressogenic cognitive responses to negative and positive life events

Abstract Maladaptive cognitive responses to stressful life events represent well-replicated risk factors for depression. Research indicates that stressful life events that are dependent on the individual to occur or are interpersonal may generate more maladaptive cognitive responses than those that are independent and/or non-interpersonal. The current study examined the roles of sex and life event domains in eliciting depressogenic cognitive responses. Participants were 212 (71% female) undergraduate students who completed seven weekly questionnaires on participant-identified most negative and most positive life events over the previous 7 days. Additionally, participants reported levels of brooding and cognitive style in response to the most negative event and levels of positive rumination and dampening in response to the most positive event. Data were analyzed using mixed ANOVAs. Results indicated that females engaged in greater brooding regardless of event dependency. In addition, dependent and interpersonal life events generated greater brooding while dependent and non-interpersonal negative events generated greater negative cognitive style. An interaction between sex and domain was observed for dampening positive life events, such that males did not differ between interpersonal and non-interpersonal life events while females were more likely to dampen following interpersonal life events than non-interpersonal events.
Some effects of ionizing radiation on tetrafluoroethylene copolymers

The effect of high energy electron radiation on TFE (tetrafluoroethylene) copolymers of perfluoro(methyl vinyl ether) (PMVE) and perfluoro-3,6-dioxa-4-methyl-7-octene sulfonyl fluoride (PSEPVE) was studied. The PMVE copolymers were found to crosslink when irradiated as either a gum or as a compounded elastomer. Attempts to graft vinyl monomers to the PMVE copolymers were unsuccessful. In contrast, grafts to PSEPVE copolymers were easily made by exposing irradiated samples to TFE or mixtures of TFE and methyl perfluoro-3,6-dioxa-4-methyl-7-octnoate.
Robotic Surgical Training Program in Gynecology: How to Train Residents and Fellows

A protocol was established to standardize surgical training using the da Vinci Surgical System. Third- and fourth-year residents and first-year fellows in obstetrics and gynecology participated. The protocol includes online instruction and 2 hands-on modules: platform set-up and surgical skills. Platform set-up provides orientation to the console, visual platform, surgical cart ("robot"), camera set-up, port placement, and instrument insertion and removal. Surgical skills includes specific drills using rubber models that simulate human tissue: manipulation, dissection, and simple and advanced suturing. Performance times were recorded for each trainee, as well as previous robotic experience. Times were compared with goals established by Intuitive Surgical, Inc., to assess feasibility of this protocol and baseline robotic surgical aptitude. All trainees (n = 17) completed the training protocol. Performance times met goals for docking and dissection. These times also varied according to level of training. Performance times for manipulation and simple and advanced suturing were prolonged across all groups. Overall pass rates were 100% for docking, 90% for dissection, 11.8% for manipulation, and 0% for simple and advanced suturing. Dissection pass rates varied according to level of training. Performance times and pass rates were not improved with higher level of training or previous robotic experience. Resident and fellow instruction in new surgical technology is an important part of training in obstetrics and gynecology. Herein is reported a method to accomplish robotic training that standardizes instruction and assessment of skills.
Large gradient across a partially ligated left atrial appendage

The left atrial appendage is frequently ligated during mitral valve surgery to decrease the future risk of embolic events. The postoperative detection of a partially occluded left atrial appendage has previously been reported with the use of transesophageal echocardiography. We describe an unusual case in which Doppler echocardiography demonstrated a remarkably high-velocity jet emanating from a partially ligated left atrial appendage.
Essential Thrust-Fourier-Coefficient Set of Averaged Gauss Equations for Orbital Mechanics

By applying an averaging method to the Gauss equations, the perturbing accelerations acting on a satellite can be represented as a function of 14 constant thrust Fourier coefficients. Time rates of change of mean orbital elements due to these thrust Fourier coefficients are analyzed, and the representation of these thrust coefficients as a function of the change in orbit states is studied. A selected minimum set of six thrust Fourier coefficients is able to provide a finite basis representation of arbitrary orbital maneuvers that allow the authors to dynamically interpolate between states across an unknown maneuver. Using this essential thrust-Fourier-coefficient set, different types of solutions are obtained, and a comparison study of these solutions is also conducted.
Hydrophobic and moisture-stable metal–organic frameworks

Metal–organic frameworks (MOFs) have proved to be very attractive for applications including gas storage, separation, sensing and catalysis. In particular, CO2 separation from flue gas in post-combustion processes is one of the main focuses of research among the scientific community. One of the major issues that are preventing the successful commercialization of these novel materials is their high affinity towards water that not only compromises gas sorption capacity but also the chemical stability. In this paper, we demonstrate a novel post-synthesis modification approach to modify MOFs towards increasing hydrophobic behaviour and chemical stability against moisture without compromising CO2 sorption capacity. Our approach consists of incorporating hydrophobic moieties on the external surface of the MOFs via physical adsorption. The rationale behind this concept is to increase the surface hydrophobicity in the porous materials without the need of introducing bulky functionalities inside the pore which compromises the sorption capacity toward other gases. We herein report preliminary results on routinely studied MOF materials [MIL-101(Cr) and NiDOBDC] demonstrating that the polymer-modified MOFs retain CO2 sorption capacity while reducing the water adsorption up to three times, with respect to the un-modified materials, via an equilibrium effect. Furthermore, the water stability of the polymer-functionalized MOFs is significantly higher than the water stability of the bare material. Molecular dynamic simulations demonstrated that this equilibrium effect implies a fundamental and permanent change in the water sorption capacity of MOFs. This approach can also be employed to render moisture stability and selectivity to MOFs that find applications in gas separations, catalysis and sensing where water plays a critical role in compromising MOF performance and recyclability.
Do differences in life history exist for blacktip sharks, Carcharhinus limbatus , from the United States South Atlantic Bight and Eastern Gulf of Mexico?

We examined life history traits (e.g., mean length-at-age, growth rate, age-at-maturity) for blacktip sharks collected from two separate geographical areas (eastern Gulf of Mexico and South Atlantic Bight) to address the potential for separate stocks in southeastern US waters. Samples were obtained from fishery-dependent and independent sources. Growth and logistic models were fitted to observed length-at-age and reproductive data, respectively. von Bertalanffy growth parameters derived for blacktip shark from the Gulf of Mexico show that they attain a statistically smaller theoretical maximum length (L ∞ = 141.6 cm vs. L ∞ = 158.5 cm for female and L ∞ = 126.0 cm FL and L ∞ = 147.4 cm FL for male) and have a faster growth rate (k = 0.24 yr−1 vs. k = 0.16 yr−1 for female and k = 0.27 yr−1 vs. k = 0.21 yr−1 for male) than conspecifics in the South Atlantic Bight. Median length- and age-at-maturity were significantly different between sex and area. Length at which 50% of the population is mature was 117.3 cm FL for females and 103.4 cm FL for males in the Gulf of Mexico and 126.6 cm FL for females and 116.7 cm FL for males in the South Atlantic Bight. Median age-at-maturity was 5.7 yrs and 4.5 yrs for females and males in the Gulf of Mexico, respectively, while age-at-maturity was 6.7 yrs for females and 5.0 yrs for males for sharks from the South Atlantic Bight. Due to varying statistical results, temporal problems of sampling, and potential for gear bias, we could not definitively conclude that differences in life history characteristics exist.
Are the effects of chronic ethanol administration on erythrocyte membrane mediated by changes in plasma lipids

Abstract The effect of chronic ethanol consumption on plasma and erythrocyte membrane lipids were studied in rats fed a liquid diet containing ethanol for 4 weeks and intubated with the same diet 90 min prior to killing. Control animals underwent the same treatment, except that their liquid diet did not contain ethanol, but an isocaloric amount of carbohydrates. Plasma total cholesterol, free (unesterified) cholesterol and HDL cholesterol were higher in ethanol-fed animals than in controls. Phospholipids were also higher in the plasma of ethanol-fed animals when compared to controls so that the plasma cholesterol/phospholipid ratio ( Ch PL ratio ) of the two groups did not differ significantly, regardless of the cholesterol fraction considered. Experimental and control animals did not differ either in the Ch PL ratio of their erythrocyte membranes. In view of the fact that it has been suggested that the factor determining the direction of the cholesterol exchanges between plasma and erythrocyte membranes is the equilibrium between their respective Ch PL ratios , these results are interpreted as being compatible with the hypothesis that the effect of chronic ethanol intake on erythrocyte membrane lipids is mediated through changes in plasma lipids.
“In the final analysis”: on Nick Nelson's contribution to the study of black politics

This essay analyzes Dr. William E. Nelson, Jr's contributions to the study of race and politics. His scholarship probed the following question: What difference has the election of this candidate or the adoption of this policy made for the Black community? Nelson emphasized the importance of political context for countering pluralist claims that fail to account for both the mobilization of bias and non-decision-making within democratic systems. In conceptualizing Black Politics, Nelson contends that the passage of policies such as the Civil Rights Act of 1964 and the Voting Rights Act of 1965 were insufficient for achieving full political incorporation. Rather, any meaningful strategy for incorporation must rest on a dual commitment to electoral participation and group empowerment. Though Nelson's early work focused on the election of Black mayors, his intellectual trajectory provides a useful framework for understanding current critiques of elected officials like Barack Obama, while also outlining a path ...
Feline immunodeficiency virus as a gene transfer vector in the rat nucleus tractus solitarii.

Gene transfer has been used to examine the role of putative neurotransmitters in the nucleus tractus solitarii (NTS). Most such studies used adenovirus vector-mediated gene transfer although adenovirus vector transfects both neuronal and non-neuronal cells. Successful transfection in the NTS has also been reported with lentivirus as the vector. Feline immunodeficiency virus (FIV), a lentivirus, may preferentially transfect neurons and could be a powerful tool to delineate physiological effects produced by altered synthesis of transmitters in neurons. However, it has not been studied in NTS. Therefore, we sought to determine whether FIV transfects rat NTS cells and to define the type of cell transfected. We found that injection of FIV encoding LacZ gene (FIVLacZ) into the NTS led to transfection of numerous NTS cells. Injection of FIVLacZ did not alter immunoreactivity (IR) for neuronal nitric oxide synthase, which we have shown resides in NTS neurons. A majority (91.7 ± 3.9%) of transfected cells contained IR for neuronal nuclear antigen, a neuronal marker; 2.1 ± 3.8% of transfected cells contained IR for glial fibrillary acidic protein, a glial marker. No transfected neurons or fibers were observed in the nodose ganglion, which sends afferents to the NTS. We conclude that FIV almost exclusively transfects neurons in the rat NTS from which it is not retrogradely transported. The cell-type specificity of FIV in the NTS may provide a molecular method to study local physiological functions mediated by potential neurotransmitters in the NTS.
CAR: A virus receptor within the tight junction

The coxsackievirus and adenovirus receptor (CAR) mediates cell attachment and infection by coxsackie B viruses and by a number of adenoviruses. CAR also mediates homotypic intercellular interactions. In polarized epithelial cells, CAR is closely associated with the tight junction, where it contributes to the barrier to paracellular flow of solutes and macromolecules. CAR's biological roles are not well defined, but emerging evidence suggests that it may function during embryonic development and in regulating cell proliferation.
Gonocyte degeneration in the postnatal male rat.

The cell population of the sex cords in rat testes from day 1 to day 10 after birth was investigated by means of microscopic observation and quantitation, and with the electron microscope. Certain gonocytes, rare during the first 2 days, more frequent thereafter, were found in various stages of pyknosis. In electron micrographs these were characterized mainly by condensed and sometimes fragmented nuclei and cytoplasmic vacuoles and vesicles. The mitochondria remained typical of gonocytes in all but the most advanced stages of necrosis. Degenerating cells were eventually surrounded by single supporting cells and apparently phagocytized by them. Gonocytes which appeared “swollen,” “fuzzy” and pale staining under the microscope were considered normal pre-mitotic cells or possibly in some cases altered by artifacts of fixation. No evidence was produced microscopically or electron microscopically that cells of this type are degenerative. In many gonocytes, the electron microscope revealed some swollen mitochondria with irregular cristae, “B-bodies” in varying numbers and occasional membrane breakage. The evidence was considered insufficient to interpret these as signs of impending cell death. Quantitative determinations of the numbers of gonocytes at various stages indicate that approximately one third of the cells are lost between day 1 and 4 post-partum. In Sprague-Dawley rats gonocytic mitoses resume on day 4. There is evidence that degeneration of gonocytes continues until day 7 or 8. The total number of cells dying may possibly be accounted for by the number of pyknotic cells observed. Incidental data are reported concerning the growth of sex cords and the proliferation of supporting cells. Comparison with results in the literature lead to the general conclusion that there is excellent evidence that many gonocytes die during the first postnatal week, but that many of the morphological criteria for dying cells used by previous investigators lack validity when rigorously examined.
Differences in the Metabolism of Postprandial Lipoproteins After a High-Monounsaturated-Fat Versus a High-Carbohydrate Diet in Patients With Type 1 Diabetes Mellitus

There is little information comparing the effects of a high-monounsaturated (Mono)-fat versus a high-carbohydrate (CHO) diet in patients with type 1 diabetes mellitus. In the present study, the effects of these diets on a number of metabolic parameters were compared. Seventeen normolipidemic, nonobese patients with type 1 diabetes were provided with the diets for 4 weeks each in a randomized, crossover design. The percentages of Mono fat of the two diets were 25 Mono versus 9 CHO, with a corresponding total fat content of 40% versus 24% and a total CHO content of 45% versus 61%. At the end of each dietary period, parameters of glycemic control, coagulation factors, and fasting and postprandial lipoproteins were assessed. There were no differences in weight, glycemia, insulin dose, fasting lipid profile, or coagulation factors between the two diets. However, the metabolism of postprandial lipoproteins after a fat load differed; viz, after the Mono diet compared with the CHO diet, mean plasma triglyceride levels over 10 hours were higher (P=.0025, by repeated-measures ANOVA). The levels of triglyceride (P=.0045) and retinyl esters (P=.0046) in chylomicrons (Sf>400) and chylomicron remnants (Sf 100 to 400) (P=.0047 and P=.043, respectively), and the total particle number (apolipoprotein B levels) in chylomicron remnants (P=.001) and small, very low density lipoprotein (Sf 20 to 100, P=.016) were also higher. Our data suggest that in patients with type 1 diabetes, a CHO diet might be preferable to a Mono diet, since adherence to the former results in a lower number of circulating postprandial lipoprotein particles that are potentially atherogenic.
Spectral dispersion and fringe detection in IOTA

Pupil plane beam combination, spectral dispersion, detection, and fringe tracking are discussed for the IOTA interferometer. A new spectrometer design is presented in which the angular dispersion with respect to wavenumber is nearly constant. The dispersing element is a type of grism, a series combination of grating and prism, in which the constant parts of the dispersion add, but the slopes cancel. This grism is optimized for the display of channelled spectra. The dispersed fringes can be tracked by a matched-filter photon-counting correlator algorithm. This algorithm requires very few arithmetic operations per detected photon, making it well-suited for real-time fringe tracking. The algorithm is able to adapt to different stellar spectral types, intensity levels, and atmospheric time constants. The results of numerical experiments are reported.
Model for Nuclear Reactions with Neutrons

A simple model is proposed for the description of the scattering and the compound nucleus formation by nucleons impinging upon complex nuclei. It is shown that, by making appropriate averages over resonances, an average problem can be defined which is referred to as the "gross-structure" problem. Solution of this problem permits the calculation of the average total cross section, the cross section for the formation of the compound nucleus, and the part of the elastic-scattering cross section which does not involve formation of the compound nucleus. Unambiguous definitions are given for the latter cross sections.The model describing these properties consists in replacing the nucleus by a one-body potential which acts upon the incident nucleon. This potential $V={V}_{0}+i{V}_{1}$ is complex; the real part represents the average potential in the nucleus; the imaginary part causes an absorption which describes the formation of the compound nucleus. As a first approximation a potential is used whose real part ${V}_{0}$ is a rectangular potential well and whose imaginary part is a constant fraction of the real part ${V}_{1}=\ensuremath{\zeta}{V}_{0}$.This model is used to reproduce the total cross sections for neutrons, the angular dependence of the elastic scattering, and the cross section for the formation of the compound nucleus. It is shown that the average properties of neutron resonances, in particular the ratio of the neutron width to the level spacing, are connected with the gross-structure problem and can be predicted by this model.The observed neutron total cross sections can be very well reproduced in the energy region between zero and 3 Mev with a well depth of 42 Mev, a factor $\ensuremath{\zeta}$ of 0.03, and a nuclear radius of $R=1.45\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}{A}^{\frac{1}{3}}$ cm. The angular dependence of the scattering cross section at 1 Mev is fairly well reproduced by the same model. The theoretical and experimental values for the ratios of neutron width to level distance at low energies and the reaction cross sections at 1 Mev do not agree too well but they show a qualitative similarity.
Testosterone lowers aromatase activity in cultured human genital skin fibroblasts

Abstract The cytochrome P-450-dependent aromatase pathway utilizes the androgens testosterone (T) and androstenedione, as substrates for estrogen formation. In addition, androgens have been shown to influence the level of aromatase activity in various tissues. In cultured human skin fibroblasts, incubation with T for 14 h resulted in a dose-dependent decline in aromatase activity, the concentration of T producing a half-maximal decline being 6 nM. In the presence of T (50 nM), aromatase activity declined in a time-dependent fashion with maximal reduction occurring by 9 h. When aromatase kinetics were determined after preincubation of cells with T, there was a significant decline in the calculated V max with no significant change in the apparent K m , suggesting that incubation of cells with T reduced the number of active enzyme sites. Aromatase activity was unaffected by preincubation of cells with the synthetic androgen methyltrienolone. In addition, the decline in aromatase activity following preincubation with T was observed in cells derived from patients with complete androgen insensitivity demonstrating that the effect of T was not mediated by androgen receptors. Furthermore, new protein synthesis was not necessary for the T-mediated effect as the presence of cycloheximide (50 μg/ml) did not prevent it. When cells were incubated at low oxygen tension, the inhibition of aromatase activity by T was diminished. Testosterone is rapidly metabolized in genital skin fibroblasts to dihydrotestosterone, androstanedione, androsterone, 3α-androstanediol, 3β-androstanediol and estradiol. To determine if a metabolite of T might be responsible for the repression of aromatase activity, aromatase activity was determined in cells following preincubation with various metabolites of T. Preincubation of cells with androstenedione, androstanedione or 3α-androstanediol produced a small but significant decline in aromatase activity, whereas preincubation of cells with dihydrotestosterone, androsterone, or 3β-androstanediol did not have a significant effect. Aromatase activity was also unaffected by preincubation of cells with estradiol or diethylstilbestrol. When aromatase activity was assayed in microsomal preparations from cells preincubated with T, activity was reduced. Although cells preincubated with 50 nM [ 3 H]T contained between 0.25 and 0.51 pmol of residual steroid/mg microsomal protein, the amount of [l- 3 H]androstenedione and T was insufficient to account for the observed decline in aromatase activity on the basis of competitive inhibition. In summary, preincubation of genital skin fibroblasts with T results in a decline in aromatase activity through a mechanism which does not involve the androgen receptor but which appears to involve a local, oxygen-mediated effect of T on the aromatase complex within the endoplasmic reticulum. We propose that incubation of cells with T may permit the destruction of the aromatase by oxygen-derived free radicals formed during aromatization.
Placing Managua: a landscape narrative in post-earthquake Nicaragua

On 23 December 1972, a major earthquake occurred near Managua, Nicaragua. Followed by two strong aftershocks, the earthquake had devastating consequences for the people of Nicaragua's capital, and corruption and mismanagement during the relief efforts gave impetus to what would become the Nicaraguan Revolution of 1979. The earthquake also dramatically altered the landscape of the capital, destroying most of the city's historic center. Abandoned after the earthquake, the area nevertheless maintains a prominent symbolic role in Nicaragua, and in many ways remains the heart of a vastly changed modern city. The revolution was celebrated in the historic core, and memorials, government buildings, and ongoing revitalization efforts have all shaped it in the nearly four decades since its devastation. Though initially abandoned, it remains a powerful and dynamic place. This article investigates landscape transitions in the historic heart of Managua since the tumultuous events of the 1970s, with particular emphasis...
Observations from the High Resolution Imaging Science Experiment (HiRISE): Martian dust devils in Gusev and Russell craters

[1] Two areas targeted for repeated imaging by detailed High Resolution Imaging Science Experiment (HiRISE) observations allow us to examine morphological differences and monitor seasonal variations of Martian dust devil tracks at two quite different locations. Russell crater (53.3°S, 12.9°E) is regularly imaged to study seasonal processes including deposition and sublimation of CO2 frost. Gusev crater (14.6°S, 175.4°E) has been frequently imaged in support of the Mars Exploration Rover mission. Gusev crater provides the first opportunity to compare “ground truth” orbital observations of dust devil tracks to surface observations of active dust plumes. Orbital observations show that dust devil tracks are rare, forming at a rate <1/110 that of the occurrence of active dust plumes estimated from Spirit's surface observations. Furthermore, the tracks observed from orbit are wider than typical plume diameters observed by Spirit. We conclude that the tracks in Gusev are primarily formed by rare, large dust devils. Smaller dust devils fail to leave tracks that are visible from orbit, perhaps because of limited surface excavation depths. Russell crater displays more frequent, smaller sinuous tracks than Gusev. This may be due to the thin dust cover in Russell, allowing smaller dust devils to penetrate through the bright dust layer and leave conspicuous tracks. The start of the dust devil season and peak activity are delayed in Russell in comparison to Gusev, likely because of its more southerly location. Dust devils in both sites travel in directions consistent with general circulation model (GCM)-predicted winds, confirming a laboratory-derived approach to determining dust devil travel directions based on track morphology.
HYPERBOLIC SMOOTHING EFFECT FOR SEMILINEAR WAVE EQUATIONS AT A FOCAL POINT

For semi-linear dissipative wave equation □u + |ut|p - 1ut = 0, we consider finite energy solutions with singularities propagating along a focusing light cone. At the tip of cone, the singularities are focused and partially smoothed out under strong nonlinear dissipation, i.e. the solution gets up to 1/2 more L2 derivative after the focus. The smoothing phenomenon is in fact the result of simultaneous action of focusing and nonlinear dissipation.
A constraint satisfaction approach to testbed embedding services

Today's networking community is becoming increasingly skeptical of the significance of research results founded wholly upon experimental results conducted in simulation. Now, with the availability of wide-area distributed testbeds such as PlanetLab, it is feasible to move beyond evaluation by simulation, and to perform wide-area experiments across the Internet as an alternate. However, while use of a distributed testbed affords much greater realism than a network simulation, there is a significant downside, as tight control over one's experiments is relinquished.We argue that providing services for distributed testbeds that capture aspects of the specifiable, repeatable behavior implicit in simulation and emulation will be an integral component of next-generation textbeds. As a case study, we consider the following problem: given a desired end-system topology consisting of a set of pairwise constraints (such as upper and lower bounds on bandwidth and delay), locate a representative subtopology within a wide-area testbed that satisfies those constraints. Previous work on Netbed addresses wide-area embedding problems of this form using an optimization framework, whereas we employ constraint satisfaction. We discuss the relative merits of these approaches, outline the theoretical foundations of a distributed service that provides a synergy between adaptive network measurements and the embedding process, and report on preliminary experimental results conducted on PlanetLab.
Spatial Variation of Convective Heat Transfer Coefficient in Air Impingement Applications

Spatial variation of heat transfer is an important factor in air impingement systems. Temperature data were obtained when a jet at room temperature impinged on a flat object initially at -50 °C to estimation heat transfer order freeze-thaw conditions. Single and double circular jets and slot jets were examined. Temprature data were fit into empirical relationships for predicting heat transfer coefficients and their spatial variation for conditions common in impingement freeze-thaw applications. For processing conditions involving cooling, the impingement surface was initially heated to a temperature of 70 °C and allowed to cool when subjected to impingement with room temperature air.
The Stalk of the Suctorian Tokophrya infusionum: Histochemistry, Biochemistry, and Physiology

SYNOPSIS Tokophrya infusionum, a sessile suctorian with an external stalk and adhesive disc, has in its life cycle a ciliated, swimming embryo which metamorphoses into the adult form. The addition of NiCl2 to the medium induced metamorphosis immediately; however, other salts had no effect. Incomplete metamorphosis, without stalk formation, occurred if the organism began metamorphosis before its anterior (stalk-forming) end touched a substrate. The stalk was studied by histochemical and biochemical technics to determine its composition. The stalk stained with mercury-bromphenol blue, and Alcian blue under a variety of conditions, but not with PAS. These results suggest that the stalk contains protein and sulfate groups, possibly in the form of a sulfated protein-polysaccharide. The stalk was insoluble in several common laboratory reagents, but did dissolve in hot 6 N HCl, 2 N NaOH, and papain. It was evident from amino acid analysis of the stalk and of the whole organism that 15% of the total protein is located in the stalk.
The challenges of conducting clinical endpoint studies

In order to evaluate the effects of a particular treatment strategy on mortality and major morbidity within a disease entity, large, multinational, relatively long-term clinical endpoint studies are often conducted. The primary challenge of conducting these studies is to maintain consistency in the interpretation of the clinical endpoints across different geographic areas and over the long time course of the study. The success of a clinical endpoint study depends on understanding the challenges and incorporating the special requirements of these studies into the protocol design and operational procedures throughout the study.
Control of the general amino acid permease of Penicillium chrysogenum by transinhibition and turnover.

Abstract When nitrogen-starved mycelium of Penicillium chrysogenum is incubated with relatively high concentrations of labeled hydrophobic amino acids, influx is followed by efflux of the corresponding labeled α-ketoacid. In spite of the efflux, further transport activity is suppressed. Cell-free extracts contain a transaminase that accepts all those amino acids exhibiting α-ketoacid efflux. Transaminase activity is constitutive but is induced to a 2- to 3-fold higher level during a 2-hr preincubation period with a hydrophobic amino acid. Cycloheximide prevents efflux and also the induction of the transaminase. Cycloheximide itself stimulates a partial decay in transport activity but mycelium preincubated with l -leucine and cycloheximide together retain a greater fraction of the original transport activity than mycelium preincubated with l -leucine alone. The results suggest that transport is regulated partially by transinhibition but a significant part of the substrate-induced decay of transport activity is caused by either (a) the degradation of a permease component (perhaps facilitated by transinhibition), or (b) the induction by the substrate of a regulator protein (perhaps the transaminase). The uptake of labeled substrates by nutrient sufficient mycelium correlates well with lipid solubility of the substrates. This suggests that the nonsaturable uptake observed in these mycelia results from free diffusion of the uncharged species.
“The Train Has Left the Station”: The Project on Emerging Nanotechnologies and the Shaping of Nanotechnology Policy in the United States

The purpose of this paper is to analyze the efforts of the Project on Emerging Nanotechnologies (PEN) in seeking to influence nanotechnology policy in the United States. Using the conceptual framework of anticipatory governance to guide the analysis, a series of strategies that PEN adopted will be described, including leveraging external expertise, developing cross-disciplinary research products, providing a future-oriented view on policy analysis, and building a brand for communications and outreach. This case study is a useful example in demonstrating the recent conceptual shift away from relying on government-led technology assessment efforts to consider the longer-term implications of new technologies toward the concept of anticipatory governance that includes a more substantive role for nongovernmental actors, that in providing forward-looking, actionable intelligence for decision makers. Considering the example of PEN also highlights the critical role that boundary-spanning organizations play in linking together disparate communities of expertise.
A Review of: “John Horgan. Walking Away From Terrorism: Accounts of Disengagement From Radical and Extremist Movements.”

Walking Away From Terrorism: Accounts of Disengagement From Radical and Extremist Movements, is an interesting book that is well worth reading. John Horgan, Director of the International Center for...