cssi/SciSciGPT-SciSciNet huggingface dataset:
Cropping sequence effects of four broadleaf crops on four cereal crops in the northern Great Plains

The productivity and cropping sequence effects of broadleaf crops are not well known within no-till systems in the semiarid northern Great Plains. We compared productivity of cool- and warm-season broadleaf crops with spring wheat (Triticum aestivum L.), measured cropping sequence effects of broadleaf crops on subsequent cereal crops, and tested if different cereal crops interacted with previous crops. During 1999-2001 we conducted 2-yr cropping sequence experiments at five sites in Montana under climatic conditions ranging from severe drought to average rainfall. Grain yield and quality were measured for chickpea (Cicer arietinum L.), flax (Linum usitatissimum L.), pea (Pisum sativum L.), proso millet (Panicum miliaceum L.), sunflower (Helianthus annuus L.), and wheat in Year 1. In Year 2, four cereal test crops [barley (Hordeum vulgare L.), durum (Triticum durum L.), spring wheat, and winter wheat] were grown following the Year 1 crops and a fallow control to measure cropping sequence effects. Comparative productivity varied among crops by site, affirming that crop diversity mitigates production risk. Under average rainfall, the cereal test crop yields following flax, pea, and chickpea ranged from 84 to 101% of the fallow control and were greater than that following wheat in seven of nine cases. However, yields following sunflower were equal or less than those following wheat. Under severe drought, cereal test crop yields following broadleaf crops ranged from 21 to 41% of the fallow control and were equal or less than those following wheat. Previous crops affected four cereal test crop species similarly.
Regulation of rat alcohol dehydrogenase by cyclic AMP in primary hepatocyte culture.

Abstract Alcohol dehydrogenase (ADH) is enhanced separately by epinephrine and by glucagon in primary rat hepatocyte culture. This study determined whether cyclic AMP, a common mediator for some of the actions of the above hormones, increases ADH. Administration of theophylline, a cyclic AMP phosphodiesterase inhibitor which increases endogenous cyclic AMP, in a dose of 100 mg/kg to rats for 5 days, increased ADH activity. Dibutyryl cyclic AMP (10 μM) added to primary hepatocytes in culture increased ADH mRNA and ADH activity at 12 and 24 h, respectively, after its addition. The increase in ADH mRNA was preceded by an increase in the expression of C/EBPβ mRNA and in C/EBPβ protein. Dibutyryl cyclic AMP, in transient transfection experiments of primary rat hepatocyte culture, activated an ADH promoter gene construct containing the C/EBP binding site, but failed to activate a construct containing a 4-bp mutation at this site. These results show that cyclic AMP induces ADH and suggests that this effect is mediated by C/EBPβ binding to the C/EBP site. The previously demonstrated induction of ADH by epinephrine and glucagon may be mediated by a common pathway via an increase in cyclic AMP.
EVIDENCE FOR COMPETITIVE RELEASE IN SIMPLIFIED SAXICOLOUS LICHEN COMMUNITIES

Saxicolous cryptogam communities were sampled quantitatively on two Potomac River island habitats in June of 1980. As a result of air pollution stress, the community on one island was found to be much simpler than that found on the other island. Two relatively pollution-tolerant foliose lichen species, Xanthoparmelia conspersa and Pseudoparmelia baltimorensis, were found to dominate the communities on both islands. An examination of niche breadth and position along a light intensity gradient demonstrated that P. baltimorensis was most frequent at low light intensities and X. conspersa was most frequent at high light intensities. However, X. conspersa exhibited a niche shift toward intermediate light intensities in the species-poor community, likely the result of reduced competitor diversity in this community since the intermediate light intensities supported the greatest number of species in the species-rich community. Niche overlap between the two species was found to occur at lower light intensities in the species-poor community, suggesting that X. conspersa is more likely to appropriate intermediate light intensities in this community. The significance of competition as a regulatory factor in lichen communities has not been fully appreciated. Since lichens and other cryptogams are frequently used as indicators of environmental quality, competitive processes in naturally occurring lichen communities must be thoroughly understood before changes in species distribution that apparently result from disturbance can be properly interpreted.
Gauging crime in late eighteenth-century London

This article uses a new method to gauge eighteenth-century crime. It counts the crimes committed against metropolitan London's justices noted in newspapers and in the Old Bailey Sessions Papers, and finds crime more prevalent than current historiography acknowledges. The article contests current claims that the manner in which newspapers noted crime constructed their readers' perception of crime, making their readers believe crime was much more horrific, and the judicial system much more just, than readers would otherwise have thought they were. The article also argues that some crimes were attacks on the powerful because they were powerful.
Mass flu vaccination of healthcare workers: not to be sniffed at

We are worried that McCartney’s article will exacerbate the current reluctance among healthcare professionals to have the influenza vaccine.1 She expresses doubts about the effectiveness of vaccinating healthcare professionals, in direct opposition to current government policy.2 Most of her conclusions seem to be based on the outcome of only a small reduction …
Dissociation potential for breaking a CH bond in methane

The potential energy along the dissociation coordinate for CH4 → CH3 + H is calculated by the multi-reference configuration interaction method, including all single and double excitations, with a triple-split-plus-diffuse-and-extended-polarization basis set. The three-parameter Lippincott and Varshni potential curves provide better approximations to the dissociation potential than does the Morse model.
MunchCrunch: a game to learn healthy-eating heuristics

Children and adolescents are at an age where they are beginning to gain autonomy over choosing the foods they eat, yet may not have adequate support or information to make informed choices. This paper describes the design of a heuristic-based health game called MunchCrunch to help this age group learn more about healthy and unhealthy foods to develop balanced eating habits.
Forecasting Freeway Link Travel Times with a Multilayer Feedforward Neural Network

One of the major requirements of advanced traveler information systems (ATISs) is a mechanism to estimate link travel times. This article examines the use of an artificial neural network (ANN) for predicting freeway link travel times for one through five time periods into the future. Actual freeway link travel times from Houston, Texas, that were collected as part of the automatic vehicle identification (AVI) system were used as a test bed. It was found that when predicting one or two time periods into the future, the ANN model that only considered previous travel times from the target link gave the best results. However, when predicting three to five time periods into the future, the ANN model that employed travel times from upstream and downstream links in addition to the target link gave superior results. The ANN model also gave the best overall results compared with existing link travel time forecasting techniques.
Bullous pemphigoid: A cause of peripheral blood eosinophilia

A retrospective study demonstrated that fourteen of twenty-eight patients (50%) with clinical, histologic, and immunofluorescent findings of bullous pemphigoid had peripheral blood eosinophilia. Blood eosinophilia ranged from 5% to 43% when first tested, with increase in one patient to 56% during treatment. The pathophysiologic cause of blood eosinophilia in bullous pemphigoid is discussed with its relationship to previously demonstrated elevations of IgE and eosinophilic chemotactic factor of anaphylaxis (ECF-A) in serum and blister fluid. Peripheral blood eosinophilia was a common finding in our group of patients, and bullous pemphigoid should be included in the differential diagnosis of bullous skin conditions with eosinophilia.
The free radical chemistry of tert-butyl formate: rate constants for hydroxyl radical, hydrated electron and hydrogen atom reaction in aqueous solution

Abstract Transients generated in situ by advanced oxidation technologies (AOTs) to destroy organic contaminants in ground and drinking water often give large concentrations of chemical by-products. These by-products may have adverse health effects, and can also interfere with the desired chemical removal by competing for the generated transients, thus lowering the overall efficiency of the remediation process. To allow for a quantitative evaluation of the influence of tert -butyl formate (TBF), a major by-product formed in the AOT destruction of methyl tert- butyl ether, rate constants for TBF reaction with the hydroxyl radical, the hydrated electron and the hydrogen atom in aqueous solution were measured in this study. Absolute values of (5.23±0.07)×10 8 , (5.48±0.09)×10 8 and (3.58±0.07)×10 6 M −1 s −1 , were determined at 22°C, respectively.
A model for electromigration and low-frequency noise in thin metal films

At stressing-current densities, low-frequency noise in thin-metal films has been known to have a 1/ƒγ component where γ is between 0.8 and 2. Although several experimental investigations have been made to measure electromigration parameters such as activation energy and lifetimes of metallization layers by low-frequency measurements, investigators so far have had to rely upon semi-empirical expressions for theory. In this paper we develop a theory connecting ion migration in metals to low-frequency noise. The model is based on the electron mobility fluctuations due to scattering from vacancies migrating along the grain boundaries. Through this model the shape of the experimentally observed low-frequency spectra, the current dependence of the noise magnitude and the frequency exponent γ, as well as the temperature dependence of γ can be accurately explained. Moreover, the model also yields the observed thermally activated form and the activation energies for the low-frequency noise magnitude.
Observation and analysis of pore pressure fluctuations in a thin colluvium landslide complex near Cincinnati, Ohio

Abstract Field observations in a thin colluvium landslide complex along the Ohio River near Cincinnati, show that measurable, late winter and spring pore water pressure increases occur when several centimetres of rain fall over a period of one or more days. Average pre-storm fillable porosity of 9% suggests that the colluvium was near saturation during the period of record. Dimensional analysis of flow through a sloping homogeneous layer of uniform thickness shows that short-term pore pressure fluctuations in very nearly saturated soils can be approximated by a one-dimensional linear diffusion equation. The concept of slope-parallel and slope-normal characteristic times is also introduced to determine the conditions under which slope-parallel and slope-normal flow will predominate. Analytical solutions to the diffusion equation are then used to investigate the effects of storm frequency and magnitude on pore pressure fluctuations. Comparison of solutions for layers of finite and infinite thickness shows that an impermeable substrate nearly doubles pore pressures along the substrate for storms of short duration; however, the effect of an impervious boundary vanishes with increasing duration. Finally, measured rainfall values are incorporated into a finite-difference simulation of the observed pore pressures, with good results.
Sisters of the Road?: The Construction of Female Hobo Identity in the Autobiographies of Ethel Lynn, Barbara Starke, and “Box-Car” Bertha Thompson

I noticed that they left out the tramp woman and girl altogether… . I have seen tramp women and girls, and they are the greatest menace to the community of any class of people who tramp. —Complaint...
Vladimir Putin and Military Reform in Russia

Abstract While it is only a beginning, Vladimir Putin has begun to take the first real steps toward reforming the Russian military. The reform plan is in place, funding has increased, some weapons modernization has begun, and most importantly, Putin placed the Chief of the General Staff back under the Defense Minister and re-wrote the General Staff's mission statement to move operational matters to the Defense Ministry. The key question is whether or not Putin will have sufficient time to make his reforms irreversible. The effort to professionalize the military has a long way to go, dedovshchina, corruption, crime, housing, pay, training all remain serious obstacles to developing a modem military, but compared with Gorbachev, who was not interested in the military or Yeltsin, who starved and undermined it, Putin seems to understand its importance and appears committed to dealing with some of its problems.
Pair distribution for a cell-model liquid

The pair distribution function for a cell-model liquid has been derived by Lund in an earlier work in the form of an integral equation which depends upon the cell-center distribution function and the cell model. From this integral equation an approximate integral equation is obtained by substituting a function, linearly dependent upon the molecular pair distribution function and a variable parameter λ, for the cell-center distribution function. This approximate integral equation is solved for the molecular pair distribution and λ is shown to depend upon the difference between temperature and the critical temperature. Although the exact numerical solution of the molecular pair distribution is not practical because of a great number of arbitrary constants of integration, the stability of phase can be noted above and below the critical point. The solution for the molecular pair distribution function is shown to agree with the Ornstein-Zernike theory in the neighborhood of the critical point.
Retracts of box products with odd-angulated factors

Let G be a connected graph with odd girth 2κ+1. Then G is a (2κ+1)-angulated graph if every two vertices of G are connected by a path such that each edge of the path is in some (2κ+1)-cycle. We prove that if G is (2κ+1)-angulated, and H is connected with odd girth at least 2κ+3, then any retract of the box (or Cartesian) product Gs H is SsT where S is a retract of G and T is a connected subgraph of H. A graph G is strongly (2κ+1)-angulated if any two vertices of G are connected by a sequence of (2κ+1)-cycles with consecutive cycles sharing at least one edge. We prove that if G is strongly (2κ+1)-angulated, and H is connected with odd girth at least 2κ+1, then any retract of Gs H is SsT where S is a retract of G and T is a connected subgraph of H or |V(S)|=1 and T is a retract of H. These two results improve theorems on weakly and strongly triangulated graphs by Nowakowski and Rival [Disc Math 70 (1988), 169–184]. As a corollary, we get that the core of the box product of two strongly (2κ+1)-angulated cores must be either one of the factors or the box product itself. Furthermore, if G is a strongly (2κ+1)-angulated core, then either Gn is a core for all positive integers n, or the core of Gn is G for all positive integers n. In the latter case, G is homomorphically equivalent to a normal Cayley graph [Larose, Laviolette, Tardiff, European J Combin 19 (1998), 867–881]. In particular, let G be a strongly (2κ+1)-angulated core such that either G is not vertex-transitive, or G is vertex-transitive and any two maximum independent sets have non-empty intersection. Then Gn is a core for any positive integer n. On the other hand, let Gi be a (2κi+1)-angulated core for 1 ≤ i≤ n where κ1 l ≥ 2. © 2006 Wiley Periodicals, Inc. J Graph Theory
Synthesis and crosslinking of partially disulfonated poly(arylene ether sulfone) random copolymers as candidates for chlorine resistant reverse osmosis membranes

Biphenol-based, partially disulfonated poly(arylene ether sulfone)s synthesized by direct copolymerization show promise as potential reverse osmosis membranes. They have excellent chlorine resistance over a wide range of pHs and good anti-protein and anti-oily water fouling behavior. Crosslinking of these copolymers that have high degrees of disulfonation may improve salt rejection of the membranes for reverse osmosis performance. A series of controlled molecular weight, phenoxide-endcapped, 50% disulfonated poly(arylene ether sulfone)s were synthesized. The copolymers were reacted with a multifunctional epoxy resin and crosslinked thermally. The effects on network properties of various factors such as crosslinking time, copolymer molecular weight and epoxy concentration were investigated. The crosslinked membranes were characterized in terms of gel fraction, water uptake, swelling and self-diffusion coefficients of water. The salt rejection of the cured membranes was significantly higher than that for the uncrosslinked copolymer precursors.
Prospective randomized comparison of conventional stress echocardiography and real-time perfusion stress echocardiography in detecting significant coronary artery disease

Background Although retrospective studies have suggested that myocardial perfusion and wall motion analysis with real-time myocardial contrast echocardiography (RTMCE) improves the detection of coronary artery disease (CAD) during dobutamine or exercise stress echocardiography, a prospective randomized comparison with conventional stress echocardiography that did not use RTMCE has not been performed. Methods A total of 1,776 patients with preserved resting left ventricular wall motion undergoing dobutamine or exercise stress echocardiography for suspicion of CAD were randomized to either non-RTMCE, for which contrast was used only for the approved indication of enhancing left ventricular opacification, or RTMCE, for which contrast infusion was used in all cases to examine both wall motion and myocardial perfusion. Comparisons in test positivity, and positive predictive value in those subsequently referred for quantitative coronary angiography, were performed. Results Patients randomized to RTMCE had significantly higher test positivity (22% for RTMCE vs 15% with non-RTMCE, P = .0002). The increased test positivity occurred without a difference in positive predictive value in predicting >50% diameter stenoses by quantitative coronary angiography (67% for non-RTMCE, 73% for RTMCE). The mechanism for increased detection of CAD with RTMCE was mostly due to the detection of subendocardial wall thickening abnormalities that would have gone undetected when examining transmural wall thickening. Conclusions RTMCE improves the detection of CAD during dobutamine and exercise stress echocardiography, mainly by the detection of subendocardial ischemia.
Modules which are invariant under monomorphisms of their injective hulls

In this paper certain injectivity conditions in terms of extensions of monomorphisms are considered. In particular, it is proved that a ring R is a quasi-Frobenius ring if and only if every monomorphism from any essential right ideal of R into R(N)R can be extended to RR. Also, known results on pseudo-injective modules are extended. Dinh raised the question if a pseudo-injective CS module is quasi-injective. The following results are obtained: M is quasi-injective if and only if M is pseudo-injective and M2 is CS. Furthermore, if M is a direct sum of uniform modules, then M is quasi-injective if and only if M is pseudo-injective. As a consequence of this it is shown that over a right Noetherian ring R, quasi-injective modules are precisely pseudo-injective CS modules.
Diversity of sulfur compound production in lactic acid bacteria.

Volatile sulfur compounds such as methanethiol, dimethyl disulfide, dimethyl trisulfide, and hydrogen sulfide constitute an important fraction of Cheddar cheese flavor. These compounds are products of the catabolism of methionine and cysteine by bacteria in the cheese matrix. The objectives of this study were to examine the levels and types of volatile sulfur compounds produced from methionine by lactic acid bacteria frequently used in cheese making and to investigate cystathionine degrading activity, which may be responsible for the liberation of these compounds. Gas chromatography with headspace sampling was used to determine volatile sulfur compounds (VSC) produced by whole cells of 24 strains of lactobacilli and 13 strains of lactococci incubated with methionine. Total VSC production varied widely in the species and subspecies tested. Nearly all strains produced VSC from methionine, but the enzyme responsible for this activity remains unclear. Cystathionine-degrading ability and the effect of methionine concentration on this ability of some of the strains was investigated. Increasing the concentrations of methionine inhibited the cystathionine-degrading ability of lactococci, but not of lactobacilli. Lactococci were found to require methionine for growth, while lactobacilli required both methionine and cysteine. Because of the low level of cystathionine-degrading activity in lactobacilli and the inhibition of this activity by methionine in lactococci, VSC production is likely due to enzymes other than cystathionine β- and γ-lyase in whole cells.
Fiber optic biosensor employing Alexa-Fluor conjugated antibodies for detection of Escherichia coli O157:H7 and Shiga-like toxins

We developed an antibody-based fiber-optic biosensor to rapidly detect low levels of Escherichia coli O157:H7 and shiga-like toxins (SLTs) in ground beef samples. The principle of the sensor is a sandwich immunoassay using an antibody which is specific for E. coli O157:H7 or toxins. A polyclonal antibody was first immobilized on polystyrene fiber waveguides through a biotin-streptavidin reaction that served as the bacteria and toxin capture entity. Alexa Fluor 647 dye-labeled antibodies against E. coli O157:H7 or SLTS incubated with the waveguides were used to detect cells or toxin and generate a specific fluorescent signal, which was acquired by launching a 635 nm laser-light from an Analyte-2000. Fluorescent molecules within several hundred nanometers of the fiber were excited by an evanescent wave, and a portion of the emission light from fluorescent dye transmitted by the fiber and collected by a photodetector at wavelengths of 670 to 710 nm quantitatively. This immunosensor was specific for E. coli O157:H7 compared with multiple other foodborne bacteria. The approach was also able to detect ~0.5 μg/mL of pure SLTs and the the SLTs associated with 10 5 E. coli O157:H7 cells at stationary phase after olfoxacin induction.
Stimulation of lipid peroxidation in vivo by injected selenite and lack of stimulation by selenate.

AbstractMale weanling rats were raised on diets based on torula yeast which were deficient in vitamin E and selenium, or supplemented with these substances. They were injected intraperitoneally with sodium selenite at 2 mg Se/kg or with sodium sulfite to give the same level of sodium. Following injection, lipid peroxidation in vivo was estimated by monitoring the production of ethane, a volatile product formed on the peroxidation of ω-3-unsaturated fatty acids. In the hour following injection, vitamin E- and selenium-deficient rats injected with selenite produced 15 times as much ethane as did controls injected with sulfite. All rats in this group died from 1 to 4 hr after injection. Rats fed diets supplemented with selenite showed only a two- to threefold stimulation of ethane production by selenite and 3/4 survived. Rats fed diets supplemented with vitamin E did not produce more ethane in response to selenite injection and 3/4 survived. All four rats supplemented with both vitamin E and selenium survive...
Links between Pubertal Timing and Neighborhood Contexts: Implications for Girls' Violent Behavior.

ABSTRACT Objective: To investigate links between girls’ violent behavior, pubertal timing, and neighborhood characteristics. Method: A total of 501 Hispanic, black, and white adolescent girls and their parents were interviewed twice over a 3-year period (1995–1998). Violent behavior was assessed using the Self-Report of Offending Scale and pubertal timing was measured via menarche. This probability sample was drawn from Chicago. To characterize neighborhoods, neighborhood clusters were created. U.S. Census data were mapped onto each neighborhood cluster to represent levels of concentrated disadvantage, immigrant concentration, and residential mobility. The response rate was approximately 70%. Results: More than 25% of girls engaged in violent behavior at the second interview. Controlling for demographic indicators, previous violence, and other psychological factors, no differences were found in violent behavior as a function of menarcheal timing or neighborhood characteristics. Instead, results revealed that early maturers engaged in violent behavior only if they lived in neighborhoods characterized by high concentrated disadvantage. Early maturers in neighborhoods characterized by high concentrated disadvantaged engaged in three times the number of violent acts as early maturers in less disadvantaged neighborhoods. Depressive symptoms and previous violent behavior were also associated with girls’ subsequent violent behavior. Conclusions: Results indicated that girls who experience a double vulnerability—early maturation and neighborhoods of disadvantage—are susceptible to engaging in violent behavior. This suggests the need for clinical evaluation to examine the implications of pubertal timing and the context of girls’ behavior.
Performance Measurement Frameworks and Development of Effective Sustainable Transport Strategies and Indicators

This paper identifies seven attributes of robust performance measurement systems by analyzing five performance measurement frameworks and their use of transportation system performance indicators. The attributes are then used to examine three case studies from Europe and the United States to demonstrate the value of performance measurement frameworks for developing and improving sustainable transportation strategies and indicators. The case studies point to important considerations in formulating a robust sustainable transportation strategy at different levels of governance and also indicate the importance of ensuring alignment in an agency's vision, objectives, and monitoring systems. The characteristics of an effective framework for the development of sustainable transportation strategies include a comprehensive sustainability objective, a good connection to the goals and objectives of an agency, and vertical and horizontal integration. In addition, a framework should capture the interactions among vari...
Empirically derived relationships between fractal dimension and power law form frequency spectra

Fractal analysis and Fourier analysis are independent techniques for quantitatively describing the variability of natural figures. Both methods have been applied to a variety of natural phenomena. Previous analytical work has formulated relationships between the fractal dimension and power law form frequency spectrum. Mandelbrot (1985) has shown that difficulties arise when the ruler method for measuring dimensionality is applied to other than self-similar figures. Since an investigator presumably does not know in advance the dimensionality of a natural profile, it is essential to quantify the nature of the discrepancy for self-affine cases. In this study, a series of experiments are conducted in which discrete random series of specified spectral forms are analyzed using the fractal ruler method. The various parameters of the fractal measurement are related to the parameters of the spectral model. In this way, empirical relationships between the techniques can be derived for discrete, finite series which simulate the results of applying the fractal method to observational data.
Cuticular lipids of insects—III. The surface lipids of the aquatic and terrestrial life forms of the big stonefly, Pteronarcys californica newport

Abstract 1. 1. Surface lipid composition of the adult and naiad big stonefly differ in that a larger percentage of hydrocarbons, wax esters, free fatty acids and sterols are found on the adult, while the naiad surface lipid has more triglyceride. 2. 2. Major qualitative differences between adult and naiad surface lipids exist in the hydrocarbon fraction. Significant quantitative differences were found in all fractions except the sterol fractions. 3. 3. Results of this investigation show that the aquatic naiad form and the terrestrial adult form of the big stonefly have different surface lipid compositions. It appears that this insect's surface lipid composition varies with life stage depending upon the needed water conservation mechanism.
Effects of Collaborative Learning in Math on Sixth Graders’ Individual Goal Orientations from a Socioconstructivist Perspective

Abstract Using socioconstructivism as a theoretical framework, this study investigated the ways in which classrooms that used peer learning groups influenced students’ goals. Specifically, my goal was to examine collaborative learning as a process that may influence individuals’ social and achievement goals. After confirming that 2 sixth‐grade math teachers had fundamental beliefs supporting socioconstructivist practices, I administered surveys designed to measure achievement and social goals in their math classes to approximately 200 of their students at 2 times during the school year. I used hierarchical linear modeling techniques, with mastery, performance‐approach, and performance‐avoidance goals as dependent variables at Time 2 and a selection of social goals and achievement goals as independent variables at Time 1. At the collaborative learning level, shared achievement goals were measured by asking students questions about the importance of group work, calculated as a mean score for students in the...
Physical Morphology and Quantitative Characterization of Chemical Changes of Weathered PVC/Pine Composites

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifications, such as carbonyl and vinyl groups which are formed during weathering. These composites were subjected to three weathering regimes: exterior, accelerated xenon-arc, and accelerated UVA. The change in color was monitored using colorimetry. Fourier transform infrared spectroscopy was used to identify and quantify the chemical modifications (carbonyl formation and vinyl propagation) due to weathering. Additionally, scanning electron microscopy was employed to observe the physical morphological changes that occurred. The results showed that exterior and accelerated xenon-arc and UVA weathering regimes increased the degree of lightness, total color change, carbonyl concentration, and wood loss on the surfaces of the weathered composites. The increased carbonyl concentration during weathering implied that degradation had occurred by oxidation process. Also, oxidation and lignin (from the wood) degradation influenced the color (lightness) of PVC based WPC upon weathering.
Israel's Trade Policy Review

Historical experience does not confirm the simplistic notion that the heavier the burden of the public debt relative to GDP, the greater is the risk that governments will encounter debt-servicing difficulties. In 25 government defaults that occurred during 1998-2017, the pre-default debt-to-GDP ratios ranged from a very low of 27% (Ecuador in 2008) to a very high of 236% (Nicaragua in 2003), with a sample median of 79%. As ratios of government debt rise, some societies manage to deliver more responsible fiscal behaviour. Low debt ratios, on the other hand, often mask dangerous currency or maturity mismatches, as well as contingent liabilities, capable of suddenly impairing banks and governments. The demand for government bonds can behave unpredictably, and governments with low or high debt ratios can suddenly find themselves cut off from needed financing. Official institutions like the IMF, European Commission, and World Bank have done themselves and their member states a great disfavour by obsessing about debt ratios which do not predict fiscal outcomes.
CONFORMATIONS OF DEOXYDODECANUCLEOTIDES WITH PYRIMIDINE (6‐4) PYRIMIDONE PHOTOADDUCTS

— We have carried out molecular mechanical simulations of dodecanucleotide d(CGCGAAXYCGCG).d(CGCGX'Y'TTCGCG) with XY being CC, TC, TT and CT and X'Y'being their corresponding base paired dinucleotides on the complementary strand. Simulations were also carried out with the corresponding pyrimidine (6-4)-pyrimidone photoadducts incorporated in these dodecanucleotides. As in the case of the cyclobutane dimer incorporated dodecanucleotide structures (Rao et al., 1984), those regions of the DNA modified by6–4 pyrimidine adducts are found to undergo little conformational changes except in the dimer region. The conformational characteristics of the6–4 pyrimidine adduct incorporated structures seem to be influenced by the nature of the base at the 3' end of the dimer. Specifically, favorable hydrogen bonding interactions between the 5' end base and its preceding phosphate group are present in structures which have cytosine at the 3' end of the photodimer. The energetics of these structures relative to those without incorporated dimers have been discussed and the results have been analysed in the light of the currently prevalent ideas on the role of the6–4 photoadducts in mutagenesis in various organisms.
A Possible Cytological Basis for the ‘R’ Membrane in the Vertebrate Eye

THE ‘R’ membrane was the name coined by Brindley1 for a hypothetical retinal barrier whose penetration by a microelectrode advancing from the vitreous chamber results in a marked drop in electrical resistance and decrease in capacitance. Later, Tomita, Murakami and Hashimoto2 found that this barrier could be demonstrated in eyes from which the retina was removed, thus placing the barrier behind the retina either at the level of the pigment epithelium or at Bruch's membrane. This was afterwards confirmed by Brindley3. Since the membrane of Bruch appears to be a substantial structure in light microscopy, it was a likely candidate for the ‘R’ membrane. Electrode marking methods employed by Brown and Tasaki4 gave results compatible with this hypothesis and ruling out the retina although in fact not clearly marking Bruch's membrane as distinct from the pigment epithelium. Cohen5, using electron microscopy, cast doubt as to the role of Bruch's membrane in this phenomenon by pointing out that Bruch's membrane consisted of the basement membranes of the pigment epithelium and choroid capillaries together with a layer of loosely interwoven connective tissue. Since there is a basement membrane at the retinal-vitreous junction where no electrical change of a comparable type is noted, it seemed unlikely that Bruch's membrane had the requisite structure for significant electrical resistance.
SYMPLECTIC CORRECTORS FOR CANONICAL HELIOCENTRIC n-BODY MAPS

Symplectic correctors are developed for n-body maps (symplectic integrators) in canonical heliocentric coordinates. Several correctors are explicitly presented.
Robust Method For Estimating The Parameters Of A Linear Fm Waveform

In this paper the problem of estimating the linear and quadratic components of a chirp signal is addressed. Areas of application include adaptive optics, coherent imaging, and interferometry. These applications share the common problem of estimating the phase parameters of a received waveform. The unknown phase parameters can be estimated from flight path data collected during the imaging process or from the phase history data directly. This paper reviews briefly the most current methods for estimating the unknown chirp parameters from the phase history data. Much recent effort has been directed not only toward the accuracy of the estimated parameters but also towards computational efficiency. The ability to form accurate estimates in near real time is an important issue. The method presented in this paper relies upon unwrapping the phase history and estimating the phase parameters using a modified least squares procedure. It is shown that the proposed method leads to very accurate phase estimates. In addition, computational, complexity issues are addressed. Comparisons are made with several recent computational phase estimation procedures. The method presented here is considerably faster than recently published algorithms.
Laser-induced retinal damage threshold for repetitive-pulse exposure to 100-μs pulses.

The laser-induced retinal injury thresholds for repetitive-pulse exposures to 100-μs-duration pulses at a wavelength of 532 nm have been determined for exposures of up to 1000 pulses in an in vivo model. The ED50 was measured for pulse repetition frequencies of 50 and 1000 Hz. Exposures to collimated beams producing a minimal retinal beam spot and to divergent beams producing a 100-μm-diameter retinal beam spot were considered. The ED50 for a 100-μs exposure was measured to be 12.8 μJ total intraocular energy for a minimal retinal beam spot exposure and 18.1 μJ total intraocular energy for a 100-μm-diameter retinal beam spot. The threshold for exposures to N>1 pulse was found to be the same for both pulse repetition frequencies. The variation of the ED50 with the number of pulses is described well by the probability summation model, in which each pulse is considered an independent event. This is consistent with a threshold-level damage mechanism of microcavitation for single-pulse 100-μs-duration exposures. The data support the maximum permissible exposure levels for repetitive-pulse exposure promulgated in the most recent laser safety guidelines.
Properties and Potential of High-Temperature Niobium Beryllides

Recent research on the low- and high-temperature properties of two beryllium-niobium intermetallic compounds, Be12Nb and Be17Nb2, is reviewed and discussed. Strength (bend and compression), hardness and fracture toughness has been mapped as a function of test temperature up to 1200°C. Results for hot-isostatically-pressed Be12Nb and Be17Nb2 are highlighted illustrating the potential for reasonable strength at both low and high temperatures. Chemical compatibility between Be12Nb and several high-temperature materials such as SiC, Al2O3, MoSi2 and various refractory metals is evaluated. Limitations for the structural use of the beryllides are identified and discussed including low-temperature toughness, intermediate-temperature embrittlement, high-temperature creep strength and composite compatibility.
A Method of Calculation for Simulation of Action Potentials

A new method is presented of calculating digital computer simulations of propagating nerve or cardiac action potentials. The calculation is of the implicit type and is done with the "cable model" approach utilizing either well-known nerve or cardiac membrane physiological models. It does not require large computing resources for long fibers because it utilizes a "retarded potential" approach so that large matrix inversions are avoided and voltage profiles can be calculated with only eight spacesteps at one time.
Architecture as such: refutations and conjectures of quality in the work of Kengo Kuma and W. G. Clark

‘[W]hat do we mean when we speak of architectural quality? It is a question that I have little difficulty answering. […] Quality architecture to me is when a building manages to move me. What on earth moves me? How can I get this into my own work?’(Peter Zumthor, Atmospheres)
Changes in the cross-linking of collagen from rat tail tendons due to diabetes.

The acid solubility of Type I collagen from rat tail tendons decreases due to diabetes. This finding has been taken as evidence that collagen from diabetics may be more cross-linked than normal. We compared CNBr peptide maps prepared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for [3H] NaBH4-reduced tail tendons from streptozotocin-diabetic rats with maps from age-matched control rats. At least through 30 weeks of diabetes, the distribution of mass of both cross-linked and uncross-linked CNBr peptides was identical in diabetic and control tendons. Therefore, the number of cross-linked peptides did not increase due to diabetes. We analyzed the 3H-cross-linking compounds present on the CNBr peptides and found that the 3H content of peptides cross-linked in control tendons through the bivalent, reduced cross-links hydroxylysinonorleucine and lysinonorleucine was diminished on corresponding peptides from diabetic tendons as a function of duration of diabetes. The cross-linked peptides, however, persisted. Therefore, we conclude that a larger fraction of these bivalent cross-links is found in an unknown, non-reducible form in tendons from diabetic compared with control rats. This resembles a phenomenon normally associated with maturation and/or aging where the non-reducible form of the cross-links is acid-stable. An increase in the fraction of the cross-links that is non-reducible and acid-stable would explain, at least in part, the decrease in acid solubility of the collagen. Non-enzymatic glycation (NEG) was not very specific, since most CNBr peptides bound some glucose. However, peptides from the α2-chain seemed to be preferential targets for NEG. While NEG clearly increased due to diabetes, we found no evidence that increased NEG led to an increased number of cross-links in tail tendon collagen from streptozotocin diabetic rats.
Theoretical and experimental characterization of a near-field scanning microwave microscope (NSMM)

An important aspect to understanding near-field optics and imaging involves the electromagnetic scattering characteristics of objects illuminated by the near field of a sub-wavelength-sized aperture. This paper addresses one particular application of near-field optics: a transmission-mode near-field scanning microscope (NSM). Specifically, some peculiar phenomena are investigated including a near-field focusing effect, as well as an impedance-based image-shape effect. To this end, we first describe the physical attributes of an NSM and then present two computational models we use to characterize this instrument. Both moment-method and finite-difference time-domain models are discussed. These two models are applied to the analysis of the NSM for various configurations and compared to other theoretical and experimental results. Finally, the construction of an X-band NSM is described - which we label a near-field scanning microwave microscope (NSMM) - and the experimental near-field imaging measurements are compared with our numerical predictions.
Agency Conflicts, Prudential Regulation, and Marking to Market ∗

We develop a model of a financial institution to show how prudential capital regulation and mark-to-market accounting interact to affect the institution’s project choices in the presence of shareholder—debt holder agency conflicts. We demonstrate that, relative to a benchmark “pure historical cost” regime in which assets and liabilities on an institution’s balance sheet are measured at their origination values, mark-to-market or fair value accounting could alleviate the inefficiencies arising from asset substitution, but exacerbate t arising from underinvestment due to debt overhang. The inefficiencies due to underinvestmen t and asset substitution work in opposing directions. An increase in the propensity for asset substitution mitigates underinvestment, and this tradeoff is especially pronounced for highly levered financial institutions. The optimal choices of the accounting measurement regime and prudential solvency constraint balance the conflicts between shareholders and debt holders. Under fair value accounting, the optimal solvency constraint declines with the institution’s marginal cost of investment in project quality and the excess cost of equity capital relative to debt capital. The optimal solvency constraint is institution-specific, which suggests that a uniform solvency constraint could be sub-optimal. In fact, if the solvency constraint in the fair value regime is sub-optimally chosen to be tighter than a threshold, historical cost accounting dominates fair value accounting.
The potential role of non‐Newtonian rheology in the resurfacing of Venus

Several analyses of the impact cratering record on Venus have concluded that 80% of Venus was resurfaced sometime in the last 300 m.y.–700 m.y. The cratering record further indicates that the resurfacing took place over a 30 m.y. - 100 m.y. interval. Since this period, there has been little large scale tectonic activity on Venus. This study proposes that such behavior may result from the interaction of phase change induced avalanches with a non-Newtonian lithosphere. The mechanism proposed here suggests that because of non-Newtonian rheology, the Venusian lithosphere becomes highly mobile during brief periods when avalanches occur. Afterwards, due to the reduction in stress levels, the lithosphere becomes rigid and large scale tectonics ceases.
Scientific Reproducibility, Human Error, and Public Policy

One of the hallmarks of scientific progress is the ability to identify and control or reduce newly discovered sources of bias and error. In response to emerging evidence that a great deal of scientific work may not be reproducible, the National Institutes of Health recently launched a reproducibility initiative to validate data published in landmark studies. The editors of Nature and Science have also announced steps that their journals will take to promote reproducibility. Efforts by scientific groups to promote reproducibility are focused mostly on measures aimed at reducing biases and errors related to experimental design and statistical analysis, some of which include reporting of data and methods fully, using control groups and blinding, and ensuring that studies are adequately powered. Although implementing such measures is essential to promoting reproducibility, it is also important for scientists to address bias and errors affecting their own judgment and reasoning. Taking human error seriously has significant ramifications for scientific practice, communication, and policy.
Functional Anatomy of T Cell Activation and Synapse Formation

T cell activation and function require a structured engagement of antigen-presenting cells. These cell contacts are characterized by two distinct dynamics in vivo: transient contacts resulting from promigratory junctions called immunological kinapses or prolonged contacts from stable junctions called immunological synapses. Kinapses operate in the steady state to allow referencing to self-peptide-MHC (pMHC) and searching for pathogen-derived pMHC. Synapses are induced by T cell receptor (TCR) interactions with agonist pMHC under specific conditions and correlate with robust immune responses that generate effector and memory T cells. High-resolution imaging has revealed that the synapse is highly coordinated, integrating cell adhesion, TCR recognition of pMHC complexes, and an array of activating and inhibitory ligands to promote or prevent T cell signaling. In this review, we examine the molecular components, geometry, and timing underlying kinapses and synapses. We integrate recent molecular and physiological data to provide a synthesis and suggest ways forward.
The application of magnetic force differentiation for the measurement of the affinity of peptide libraries

A new method has been developed for measuring the binding affinity of phage displayed peptides and a target protein using magnetic particles. The specific interaction between the phage displayed peptides and the target protein was subject to a force generated by the magnetic particle. The binding affinity was obtained by analyzing the force–bond lifetime.