Value ofC Research Articles

Carboniferous isotope stratigraphy

Abstract We present an updated set of Carboniferous Sr, C and O isotope stratigraphies based on the existing literature, given the importance of chemostratigraphy for stratigraphic correlation in the Carboniferous. The Carboniferous 87 Sr/ 86 Sr record, constructed using brachiopods and conodonts, exhibits five first-order phases beginning with a rapid decline from a peak value of c. 0.70840 at the Devonian–Carboniferous boundary to a trough (0.70776–0.70771) in the Visean followed by a rise to a plateau ( c. 0.70827) in the upper Bashkirian. A decline to c. 0.70804 follows from the lowermost Gzhelian to the close of the Carboniferous. Contemporaneous carbonate δ 13 C records exhibit considerable variability between materials analysed and by region, although pronounced excursions (e.g. the mid-Tournaisian positive excursion and the end-Kasimovian negative excursion) are present in most records. Bulk carbonate δ 13 C records from South China and Europe, however, are generally consistent with those of brachiopod calcite from North America in terms of both absolute values and trends. Both brachiopod calcite and conodont phosphate δ 18 O document large regional variability, confirming that Carboniferous δ 18 O records are invalid for precise stratigraphic correlation. Nevertheless, significant positive δ 18 O shifts in certain intervals (e.g. mid-Tournaisian and the Mississippian–Pennsylvanian transition) can be used for global correlation.

The first bismuth borate oxyiodide, Bi4BO7I: commensurate or incommensurate?

The first bismuth borate oxyiodide, Bi4BO7I, has been prepared by solid-state reaction in evacuated silica ampoules. Its crystal structure [space group Immm(00γ)000] comprises litharge-related layers of edge-sharing OBi4 tetrahedra; the interlayer space is filled by I- and [BO3]3- anions. The wavevector, q= 0.242 (3)c*, is very close to the rational value of c*/4, yet refinement based on commensurate modulation faces serious problems indicating the incommensurate nature of the modulation. The I-/[BO3]3- anions are ordered in a complex sequence along [001], i.e. -<-BO3-BO3-I-I->n=28-I-I-I-<-BO3-BO3-I-I->n= 28-BO3-BO3-BO3-, leading to a structural modulation. The principal feature of the latter is the presence of -I-I-I- and -BO3-BO3-BO3- sequences that cannot be accounted for in the a× b× 4c supercell. The thermal expansion of Bi4BO7I is weakly anisotropic (αa= 8, αb= 15 and αc= 17× 10-6 K-1 at 500 K) which is caused by preferential orientation of the borate groups.

No evidence of homeostatic regulation of leaf temperature in Eucalyptus parramattensis trees: integration of CO2 flux and oxygen isotope methodologies.

Thermoregulation of leaf temperature (Tleaf ) may foster metabolic homeostasis in plants, but the degree to which Tleaf is moderated, and under what environmental contexts, is a topic of debate. Isotopic studies inferred the temperature of photosynthetic carbon assimilation to be a constant value ofc.20°C; by contrast, leaf biophysical theory suggests a strong dependence of Tleaf on environmental drivers. Can this apparent disparity be reconciled? We continuously measured Tleaf and whole-crown net CO2 uptake for Eucalyptus parramattensis trees growing in field conditions in whole-tree chambers under ambient and+3°C warming conditions, and calculated assimilation-weighted leaf temperature (TL-AW ) across 265d, varying in air temperature (Tair ) from -1 to 45°C. We compared these data to TL-AW derived from wood cellulose δ18 O. Tleaf exhibited substantial variation driven by Tair , light intensity, and vapor pressure deficit, and Tleaf was strongly linearly correlated with Tair with a slope ofc.1.0. TL-AW values calculated from cellulose δ18 O vs crown fluxes were remarkably consistent; both varied seasonally and in response to the warming treatment, tracking variation in Tair . The leaves studied here were nearly poikilothermic, with no evidence of thermoregulation of Tleaf towards a homeostatic value. Importantly, this work supports the use of cellulose δ18 O to infer TL-AW , but does not support the concept of strong homeothermic regulation of Tleaf.

Relationship between Candida albicans and Streptococcus mutans in early childhood caries, evaluated by quantitative PCR.

Background: The aim of this study was to analyze the synergistic relationship between Candida albicans and Streptococcus mutans in children with early childhood caries (ECC) experience. Methods: Dental plaque and unstimulated saliva samples were taken from 30 subjects aged 3-5 years old, half with (n=15, dmft > 4) and half without (n=15) ECC. The abundance of C. albicans and S. mutans and relative to total bacteria load were quantify by real-time PCR (qPCR). This method was also employed to investigate the mRNA expression of glycosyltransferase ( gtfB) gene in dental plaque. Student's t-test and Pearson's correlation were used to perform statistical analysis. Results: Within the ECC group, the quantity of both microorganisms were higher in the saliva than in dental plaque. The ratio of C. albicans to total bacteria was higher in saliva than in plaque samples (p<0.05). We observed the opposite for S. mutans (p < 0.05). The different value of C. albicans and S. mutans in saliva was positively correlated, and negatively correlated in dental plaque. Transcription level of S. mutans gtfB showed a positive correlation with C. albicans concentration in dental plaque. Conclusion:C. albicans has a positive correlation with cariogenic traits of S. mutans in ECC-related biofilm of young children.

Thermoeconomic analysis and optimization of a novel inlet air cooling system with gas turbine engines using cascaded waste-heat recovery

Gas turbines usually suffer from remarkable drop in power and excessive increase in fuel consumption when running under part load or high ambient temperatures. The two deficiencies are overcome by cogeneration and inlet air cooling respectively.Energy analysis was previously carried out for this innovative system. In this work, a thermoeconomic analysis is further done using specific exergy costing method by combining the energy and the exergy analysis with the economic analysis to evaluate the total operating cost of the system over a wide range of operating variables, namely: Expander 1, Turbine inlet temperatures, pressure ratios of gas turbine, upper and lower propane cycles. Beside the total operating cost of CWHRS as the main performance variable, total generated power, thermal and exergy efficiency are considered in the analysis. The results at the design point are: C˙Total = 2.69 (USUS$/s), P˙Net = 48.46 MW, ηThermal = 30.38% and η11 = 37.23%.Optimization, by using the direct search method and the EES Software resulted in a final value ofC˙Total = 1.715 (USUS$/s), P˙Net = 27135 (kW) and ηThermal = 28.34%. Furthermore, sensitivity study is carried out showing the drop of 10% of the operating variables and its effect on the total operating cost.

Getting to the core of cadherin complex function in Caenorhabditis elegans.

The classic cadherin-catenin complex (CCC) mediates cell-cell adhesion in metazoans. Although substantial insights have been gained by studying the CCC in vertebrate tissue culture, analyzing requirements for and regulation of the CCC in vertebrates remains challenging. Caenorhabditis elegans is a powerful system for connecting the molecular details of CCC function with functional requirements in a living organism. Recent data, using an “angstroms to embryos” approach, have elucidated functions for key residues, conserved across all metazoans, that mediate cadherin/β-catenin binding. Other recent work reveals a novel, potentially ancestral, role for the C. elegans p120ctn homologue in regulating polarization of blastomeres in the early embryo via Cdc42 and the partitioning-defective (PAR)/atypical protein kinase C (aPKC) complex. Finally, recent work suggests that the CCC is trafficked to the cell surface via the clathrin adaptor protein complex 1 (AP-1) in surprising ways. These studies continue to underscore the value of C. elegans as a model system for identifying conserved molecular mechanisms involving the CCC.

Optimal Codes in the Enomoto-Katona Space

Coding in a new metric space, called the Enomoto-Katona space, has recently been considered in connection with the study of implication structures of functional dependencies and their generalizations in relational databases. The central problem is the determination ofC(n,k,d), the size of an optimal code of lengthn, weightk, and distancedin the Enomoto-Katona space. The value ofC(n,k,d) was known only for some congruence classes ofnwhen (k,d) ∈ {(2,3),(3,5)}. In this paper, we obtain new infinite families of optimal codes in the Enomoto-Katona space and verify a conjecture of Brightwell and Katona in certain instances. In particular,C(n,k, 2k− 1) is determined for all sufficiently largensatisfying eithern≡ 1 modkandn(n− 1) ≡ 0 mod 2k2, orn≡ 0 modk. We also give complete solutions fork= 2 and determineC(n,3,5) for certain congruence classes ofnwith finite exceptions.

Study on the ethnopharmaceutical values and traditional uses of Capparis spinosa L.

This paper highlights the ethno-pharmaceutical importance of Capparis spinosa L. (Capparidaceae) used by many local people of district Chitral since century under the traditional system of medicine. In this context, a survey was conducted during summer 2010 in different ecologically and economically important sites of the study area. The aims, the current endeavour was to prepare an ethno-pharmaceutical inventory of C. spinosa and also to raise awareness regarding its usage. Additionally, to explore its agro-industrial potentialities for the socio-economic uplift of the inhabitants of district Chitral, Pakistan. The methodology of the survey focused on a series of consultation with local hakims (traditional healers) and people of different age groups. The results revealed that C. spinosa is a multipurpose plant used for the curing of various human illnesses in traditional system of medicines. The young fruits and tender branch tips are used in pickled and also as a condiment agent. The study also revealed that the tender young shoots including immature small leaves are eaten as a vegetable. Additionally, ash from burned caper roots has been used as a source of salt in indigenous system. Generally men had a greater knowledge than women regarding the therapeutic value ofC. spinosa. This species is mostly collected by children and women and gathering is generally done for supplementary income. The collectors are not properly trained in the post harvest treatment of collected materials. Recommendations are given in the spheres of training in identification, sustainable collection, processing, value addition, equitable sharing of benefits ofC. spinosa, trade monitoring and cooperative system of marketing. Key words: Capparis spinosa, multipurpose species, ethno-pharmaceutical value, local people, traditional system of medicine, human illnesses.

Copper Accumulation and Tolerance of &lt;i&gt;Chlorophytum comosum&lt;/i&gt;

In this study, Copper (Cu) tolerance inChlorophytum comosumwas tested by pot-planting. The results showed that the tolerance index (TI) ofC. comosumwas above 100 in soil Cu concentration of 50mg·kg-1. With the increase of Cu concentration in soil, the MDA content increased, but had no significant differences with the control until 500mg·kg-1. The value of chlorophyll a/b had no significant differences with the control in all treatments. Meanwhile, the bioaccumulation coefficient (BC) and translocation factor (TF) value ofC. comosumwere 1.287 and 0.687 respectively in Cu concentration of soil up to 500mg·kg-1. For the advantages of high tolerance, high accumulation and high ornamental value,C. comosummay be a potential Cu-accumulator and have tremendous application value in the treatment of Cu-contaminated soils.

Fluctuations and effective temperatures in coarsening

We study dynamic fluctuations in non-disordered finite dimensionalferromagnetic systems quenched to the critical point and the low temperaturephase. We investigate the fluctuations of two two-time quantities, calledχ andC, theaverages of which yield the self-linear response and correlation functions. We introduce a restricted averageof the χs, summing over all configurations with a given value ofC. We find that therestricted average ⟨χ⟩C obeys a scaling form, and that the slope of the scaling function approaches the universalvalue of the limiting effective temperature in the long time limit and for . Our results tend to confirm the expectation that time-reparameterization invariance isnot realized in coarsening systems at criticality. Finally, we discuss possible experimentaltests of our proposal.

System size dependence of the transport coefficients and Stokes–Einstein relationship ofhard sphere and Weeks–Chandler–Andersen fluids

Molecular dynamics simulations have been used to calculate the self-diffusion coefficient,D, and other transport coefficients of the hard sphere and Weeks–Chandler–Andersen (WCA)fluids over a wide density range. Simulations were carried out with different numbers of particles,N, in the range between 500 and 273 375 for the WCA and up to 10 976 for the hard spherefluid. These data were fitted to the relationship , where the parameters , A and α were all allowed to be density dependent. The self-diffusion coefficient in the thermodynamiclimit was obtained for both fluids. The Stokes–Einstein (SE) relationship stick–slip parameter,c = kBT/πDηs, wherekB is Boltzmann’sconstant, T is thetemperature and ηs is the shear viscosity, was calculated for the two fluids at each state point as a function ofN. Because of therelatively strong N dependence of D, theparameter c is alsoshown to be sensitive to N. It is shown that data taken for a few hundred particles can significantly overestimate the value ofc. At liquid-like densities, with increasing system size,c tends towards the slip value of 2. The same trend is observed for hard spheresand WCA particles. Therefore for any study of the SE stick–slip parameter it isimportant to perform several simulations for different system sizes and extrapolate theself-diffusion coefficient to the thermodynamic limit, and it is this value which shouldbe used to compare with theory. At the same packing fraction the self-diffusioncoefficient of the WCA fluid is larger than the value for the hard sphere fluidin the thermodynamic limit by, for example, 10% at a packing fraction of0.3 and 60% at a packing fraction of 0.49. The trend for the shear viscosity is the reverse, bothof which could be attributed to the softness of the potential in the WCA case and itseffect in inducing more cooperative interparticle trajectories than for the hardsphere.

The Frequency ofChlamydia trachomatisMajor Outer Membrane Protein-Specific CD8+T Lymphocytes in Active Trachoma Is Associated with Current Ocular Infection

Chlamydia-specific cytotoxic T lymphocytes are able to control model infections but may be implicated in disease pathogenesis. HLA-A2 peptide tetramers to Chlamydia trachomatis major outer membrane protein 258-266 (MOMP258-266) and MOMP260-268 were used to characterize HLA class I-restricted CD8+ T cells in Gambian children aged 4 to 15 years with clinical signs of active trachoma and/or infection with C. trachomatis. The frequencies of circulating HLA-A2 tetramer binding cells (TBC) were determined in whole blood samples by flow cytometric analysis. Initial screening of subjects with an anti-HLA-A2 antibody confirmed the presence of either HLA-A2 or HLA-A28. These were subsequently further divided by molecular subtyping. The C. trachomatis-specific HLA-A2 peptide tetramers were able to bind T cells with receptors from subjects which were restricted by either the HLA-A2 or the HLA-A28 restriction element. In this population, the median value of C. trachomatis-specific CD8+ T cells was 0.02%, with frequencies of up to 3.71% of CD8+ T cells reactive with a single tetramer in a minority of subjects. TBC were detected more often in subjects who were infected at the ocular surface, and their presence was associated with infection episodes of longer duration. Detection of C. trachomatis-specific TBC was not associated with the presence of disease or with the estimated load of ocular C. trachomatis infection at the time of sample collection. High frequencies of C. trachomatis-specific cells did not predict subsequent appearance or resolution of the clinical disease signs of active trachoma.

Measurement of carbon dioxide production in very low birth weight babies

BACKGROUNDCO2production is most commonly measured by using indirect calorimetry to quantify elimination of CO2 in breath (Vco2). An alternative is to measure the rate at which CO2 appears in the...

The Kolmogorov Expression Complexity of Logics

The purpose of the paper is to propose a completely new notion of complexity of logics in finite-model theory. It is the Kolmogorov variant of the Vardi'sexpression complexity. We define it by considering the value of the Kolmogorov complexityC(L[A]) of the infinite stringL[A] of all truth values of sentences ofLin A. The higher is this value, the more expressive is the logicLin A. If D is a class of finite models, then the value ofC(L[A]) over all A∈D is a measure of expressive power ofLin D. Unboundedness ofC(L[A])−C(L′[A]) for A∈D implies nonexistence of a recursive interpretation ofLinL′. A version of this statement with complexities modulo oracles implies the nonexistence of any interpretation ofLinL′. Thus the valuesC(L[A]) modulo oracles constitute an invariant of the expressive power of logics over finite models, depending on their real (absolute) expressive power, and not on the syntax. We investigate our notion for fragments of the infinitary logic Lω∞ω: least fixed point logic (LFP) and partial fixed point logic (PFP). We prove a precise characterization of 0–1 laws for these logics in terms of a certain boundedness condition placed onC(L[A]). We get an extension of the notion of a 0–1 law by imposing an upper bound on the value ofC(L[A]) growing not too fast with cardinality of A, which still implies inexpressibility results similar to those implied by 0–1 laws. We also discuss classes D in whichC(PFPk[A]) is very high. It appears that then PFP or its simple extension can define all the PSPACE subsets of D.

Preliminary study on the source field mode of geomagnetic six-month-period variations

The monthly means of north component X of geomagnetic field from 16 observatories during 1984–1988 were analyzed using the Sompi spectral analysis technique Most of these observatories are located in China. The analysis of the semiannual variations indicates that the latitude has no apparent effect on the X component. This clearly implies that the source field mode of semiannual variations cannot simply be described by using the p10 mode. Using the p10 mode to estimate the inductive scale lengthC in the semiannual period, the value ofC at each observatory would be biased significantly. The purpose of this study is to find which kind of modes is optimal for estimating the values ofC corresponding to the semiannual variations. The results show that a composite mode, involving five terms Pn0(n = 1,, 5), might be a reasonable and acceptable one

The value ofC efor the Arabian Sea during summer monsoon

We estimate, from the moisture budget the bulk aerodynamic coefficient for latent heat flux (Ce) during the monsoon season over the central Arabian Sea. The average value ofCeunder active monsoon conditions was found to be 2.25 × 10−3 which is nearly 60% higher than those previously used.

Chain entanglement, mechanical properties and drawability of poly(lactide)

The observed brittle fracture behavior of amorphous polylactides seems to be contradicted by the low value ofC ∞ =2 determined for poly(L-lactide) by Flory and coworkers. Such very flexible polymer chains deform by shear yielding, and fracture in a ductile manner. In this study,C ∞ was estimated in a number of ways, resulting in much higher values ofC ∞ =11.7 andC ∞=9.1 for poly(L-lactide) and L- and D-lactide copolymers, respectively. These high values ofC ∞ and the low entanglement density account for the brittle fracture behavior of amorphous poly(lactide), as well as for the maximum attainable draw ratios of poly(L-lactide) networks and melt spun fibers. Bulk polymerized poly(L-lactide) networks, where crystallization during polymerization impedes severe entangling, could be hot-drawn most effectively to draw ratios of 8–16, resulting in very strong materials with tensile strengths of 550–805 MPa. By comparison, amorphous, non-crystallizable L/D lactide networks, which do not crystallize during polymerization, could be drawn less, to λ=7. These materials with strengths up to 460 MPa could, nevertheless, be oriented much more effectively than linear, amorphous L/D lactide copolymers.

Measurement of solid solubility of germanium in aluminum

The solid solubility of Ge in aluminum was determined by resistivity measurement at 77 K of Al-Ge alloys annealed at various temperatures for times sufficient to complete the precipitation of the equilibrium Ge phase. The solid solubility of Ge in aluminum was found to vary from 0.252 at. pct at 533 K to 1.82 at. pct at 693 K. From the temperature dependence of the solid solubilities, the excess entropy of mixing ΔS and heat of mixing ΔH associated with the formation of solid solution of Ge in aluminum were calculated to be 2.77 R and 38.5 kJ mol-1, respectively. Using these values of ΔS and ΔH, the maximum solid solubility of Ge in aluminum was calculated to be 2.08 at. pct at the eutectic temperature 697 K. The magnitude ΔρGe77/Δc due to 1 at. pct impurity was determined to be 8.60 nΩm/at. pct Ge. The resistivity of Al-1.32 at. pct Ge alloys aged at 573 and 623 K was measured at 77 K to determine the time variation of the average concentrationc of the solute in the matrix during coarsening of the Ge precipitates. The value ofc, calculated using the value of ΔρGe77/Δc, decreased linearly in accordance with the t-1/3 law. The concentration of the solute in the matrix, in equilibrium with the Ge particle of infinite size, was determined by extrapolating thec vs t-1/3 plot to infinite time, in excellent agreement with the above solid solubility.

Effect of feeding Carica papaya (Papita) fruits on blood lipid profile of albino rabbits

Effect of feeding ripe and unripe papaya fruit pulps were investigated on blood lipid profile of normal male adult albino rabbits by giving them pulps separately at the dose of 15 and 30g per day along with standard diet over a period of six weeks. As compared to controls both fruit pulps resulted in highly significant (p<0.001) and consistent lowering of serum cholesterol, low density lipoprotein cholesterol and triglycerides and elevation in phospholipids and high density lipoprotein cholesterol levels at 1,3 and 6 weeks of fruit pulp feeding indicating a dose dependent effect. Observations clearly support medicinal value ofC. Papaya in the management of atherosclerosis, fatty liver, ischaemic changes and consequential myocardial infarction.

Quantization on the Virasoro group

The quantization of the Virasoro group is carried out by means of a previously established group approach to quantization. We explicitly work out the two-cocycles on the Virasoro group as a preliminary step. In our scheme the carrier space for all the Virasoro representations is made out of polarized functions on the group manifold. It is proved that this space does not contain null vector states, even forc≦1, although it is not irreducible. The full reduction is achieved in a striaghtforward way by just taking a well defined invariant subspace ℋ (c, h) , the orbit of the enveloping algebra through the vacuum, which is irreducible for any value ofc andh. ℋ (c, h) is a proper subspace of the space of polarized functions for those values ofc andh for which the Kac determinant is zero. We give the local version of these group representations as well as the associated classical phase space structures, i.e., symplectic form and Noether invariants.