NUTRIENT DEMAND BY THE CARROT CROP IS INFLUENCED BY THE CULTIVAR

Farmers must carefully choose the cultivar to be grown for a successful carrot crop. The yield potential of the cultivar may influence nutrient demand and should be known to plan for fertilization application. The aim of this study was to evaluate the cultivar effect on carrot yield and on the nutrient content and quantities allocated to leaves and roots. Three experiments were set up in two crop seasons in Rio Paranaíba, MG, Brazil. In the first season, typical summer, 10 summer cultivars were sown. In the second season, summer-winter (transition), two experiments were set up, one with summer cultivars and the other with winter cultivars. The treatments consisted of the carrot cultivars distributed in randomized blocks with four replications. Fresh and dry matter of the roots and leaves was quantified. Yield was calculated based on fresh matter of the roots. The nutrient content in leaves and roots was determined at the time of harvest. These contents and the dry matter production of roots and leaves were used to calculate nutrient uptake and export. The greatest average for total and commercial yield occurred in the crop under summer conditions. Extraction of N and K for most of the cultivars in the three experiments went beyond the amounts applied through fertilizers. Thus, there was contribution of nutrients from the soil to obtain the yields observed. However, the amount of P taken up was considerably less than that applied. This implies that soil P fertility will increase after cropping. The crop season and the cultivars influenced yield, nutrient content in the leaves and roots, and extraction and export of nutrients by the carrot crop.

Dynamical properties of the Zhang model of self-organized criticality

Critical exponents of the infinitely slowly driven Zhang model of self-organized criticality are computed for d=2 and 3, with particular emphasis devoted to the various roughening exponents. Besides confirming recent estimates of some exponents, new quantities are monitored, and their critical exponents computed. Among other results, it is shown that the three-dimensional exponents do not coincide with the Bak-Tang-Wiesenfeld [Phys. Rev. Lett. 59, 381 (1987); Phys. Rev. A 38, 364 (1988)] (Abelian) model, and that the dynamical exponent as computed from the correlation length and from the roughness of the energy profile do not necessarily coincide, as is usually implicitly assumed. An explanation for this is provided. The possibility of comparing these results with those obtained from renormalization group arguments is also briefly addressed.

Stochastic resonance in a system of magnetic particles

We show that a dispersion of monodomain ferromagnetic particles in a solid phase exhibits stochastic resonance when a driven linearly polarized magnetic field is applied. By using an adiabatic approach, we calculate the power spectrum, the distribution of residence times, and the mean first passage time. The behavior of these quantities is similar to the behavior of corresponding quantities in other systems where stochastic resonance has also been observed.

Generalized adiabatic invariance

In this paper we find the quantities that are adiabatic invariants of any desired order for a general slowly time-dependent Hamiltonian. In a preceding paper, we chose a quantity that was initially an adiabatic invariant to first order, and sought the conditions to be imposed upon the Hamiltonian so that the quantum mechanical adiabatic theorem would be valid to mth order. [We found that this occurs when the first (m - 1) time derivatives of the Hamiltonian at the initial and final time instants are equal to zero.] Here we look for a quantity that is an adiabatic invariant to mth order for any Hamiltonian that changes slowly in time, and that does not fulfill any special condition (its first time derivatives are not zero initially and finally).

Characterization of Ornamental Rock Residue and Potassium Liberation Via Organic Acid Application

ABSTRACT Organic acids present in organic matter and, or, exudates by microorganisms and plants can increase the liberation of potassium present in minerals. The objective of this study was to characterize the residue from ornamental rocks and evaluate the release of K from these residues after the application of organic acids. The experiment was conducted under laboratory conditions and followed a 2 × 3 × 5 factorial design with three replicates. The studied factors were: two organic acids (citric acid and malic acid), three ornamental rock residues (R1, R2 and R3) and five organic acid rates (0, 5, 10, 20 and 40 mmol L-1). After agitation, K concentrations were determined in the equilibrium solution. Successive extractions were performed (1, 5, 10, 15, 30 and 60 days after the start of the experiment). The organic acids used (citric and malic) promoted the release of up to 4.86 and 4.34 % of the total K contained in the residue, respectively, reinforcing the role of organic acids in the weathering of minerals and in providing K to the soil. The K quantities were, on average, 6.1 % higher when extracted with citric acid compared to malic acid.

Consommation d'alcool et de benzodiozépines au troisième âge [Consumption of alcohol and benzodiazepines in the elderly]

In Switzerland, 9.1% of the general population accept regular consumption of BZD. In 65-74 years age group, 2% of cases display a high-risk alcohol consumption. Moderate risk consumption is present in 5% of cases. For the BZD, the cognitive difficulties settle in an insidious way; for alcohol, the daily consumption of fairly high quantities may lead to cognitive deterioration. At early stages, alcohol abusers show preserved neuropsychological performances. Gradually, the deficits will affect the remaining cognitive functions and become irreversible. This review indicates that the chronic consumption of alcohol and BZD in old age is at the origin of major clinical difficulties that need ad hoc training both for psychiatrists and general practitioners.

Convenient synthesis of C75, an inhibitor of FAS and CPT1

C75 is a synthetic racemic α-methylene-γ-butyrolactone exhibiting anti-tumoral properties in vitro and in vivo as well as inducing hypophagia and weight loss in rodents. These interesting properties are thought to be a consequence of the inhibition of the key enzymes FAS and CPT1 involved in lipid metabolism. The need for larger amounts of this compound for biological evaluation prompted us to develop a convenient and reliable route to multigram quantities of C75 from easily available ethyl penta-3,4-dienoate 6. A recently described protocol for the addition of 6 to a mixture of dicyclohexylborane and nonanal followed by acidic treatment of the crude afforded lactone 8, as a mixture of cis and trans isomers, in good yield. The DBU-catalyzed isomerization of the methyl esters 9 arising from 8 gave a 10:1 trans/cis mixture from which the trans isomer was isolated and easily transformed into C75. The temporary transformation of C75 into a phenylseleno ether derivative makes its purification, manipulation and storage easier.

Can we identify Walrasian allocations?

[eng] We consider a discrete time, pure exchange infinite horizon economy with two or more consumers and at least one concumption good per period. Within the framework of decentralized mechanisms, we show that for a given consumption trade at any period of time, say at time one, the consumers will need, in general, an infinite dimensional (informational) space to identigy such a trade as an intemporal Walrasian one. However, we show and characterize a set of enviroments where the Walrasian trades at each period of time can be achieved as the equilibrium trades of a sequence of decentralized competitive mechanisms, using only both current prices and quantities to coordinate decisions.

A model of cellular dosimetry for macroscopic tumors in radiopharmaceutical therapy.

PURPOSE: In the radiopharmaceutical therapy approach to the fight against cancer, in particular when it comes to translating laboratory results to the clinical setting, modeling has served as an invaluable tool for guidance and for understanding the processes operating at the cellular level and how these relate to macroscopic observables. Tumor control probability (TCP) is the dosimetric end point quantity of choice which relates to experimental and clinical data: it requires knowledge of individual cellular absorbed doses since it depends on the assessment of the treatment's ability to kill each and every cell. Macroscopic tumors, seen in both clinical and experimental studies, contain too many cells to be modeled individually in Monte Carlo simulation; yet, in particular for low ratios of decays to cells, a cell-based model that does not smooth away statistical considerations associated with low activity is a necessity. The authors present here an adaptation of the simple sphere-based model from which cellular level dosimetry for macroscopic tumors and their end point quantities, such as TCP, may be extrapolated more reliably. METHODS: Ten homogenous spheres representing tumors of different sizes were constructed in GEANT4. The radionuclide 131I was randomly allowed to decay for each model size and for seven different ratios of number of decays to number of cells, N(r): 1000, 500, 200, 100, 50, 20, and 10 decays per cell. The deposited energy was collected in radial bins and divided by the bin mass to obtain the average bin absorbed dose. To simulate a cellular model, the number of cells present in each bin was calculated and an absorbed dose attributed to each cell equal to the bin average absorbed dose with a randomly determined adjustment based on a Gaussian probability distribution with a width equal to the statistical uncertainty consistent with the ratio of decays to cells, i.e., equal to Nr-1/2. From dose volume histograms the surviving fraction of cells, equivalent uniform dose (EUD), and TCP for the different scenarios were calculated. Comparably sized spherical models containing individual spherical cells (15 microm diameter) in hexagonal lattices were constructed, and Monte Carlo simulations were executed for all the same previous scenarios. The dosimetric quantities were calculated and compared to the adjusted simple sphere model results. The model was then applied to the Bortezomib-induced enzyme-targeted radiotherapy (BETR) strategy of targeting Epstein-Barr virus (EBV)-expressing cancers. RESULTS: The TCP values were comparable to within 2% between the adjusted simple sphere and full cellular models. Additionally, models were generated for a nonuniform distribution of activity, and results were compared between the adjusted spherical and cellular models with similar comparability. The TCP values from the experimental macroscopic tumor results were consistent with the experimental observations for BETR-treated 1 g EBV-expressing lymphoma tumors in mice. CONCLUSIONS: The adjusted spherical model presented here provides more accurate TCP values than simple spheres, on par with full cellular Monte Carlo simulations while maintaining the simplicity of the simple sphere model. This model provides a basis for complementing and understanding laboratory and clinical results pertaining to radiopharmaceutical therapy.

Use of nanoparticles in Swiss industry: a targeted survey

A large number of applications using manufactured nanoparticles of less than 100 nm are currently being introduced into industrial processes. There is an urgent need to evaluate the risks of these novel particles to ensure their safe production, handling, use, and disposal. However, today we lack even rudimentary knowledge about type and quantity of industrially used manufactured nanoparticles and the level of exposure in Swiss industry. The goal of this study was to evaluate the use of nanoparticles, the currently implemented safety measures, and the number of potentially exposed workers in all types of industry. To evaluate this, a targeted telephone survey was conducted among health and safety representatives from 197 Swiss companies. The survey showed that nanoparticles are already used in many industrial sectors; not only in companies in the new field of nanotechnology, but also in more traditional sectors, such as paints. Forty-three companies declared to use or produce nanoparticles, and 11 imported and traded with prepackaged goods that contain nanoparticles. The following nanoparticles were found to be used in considerable quantities (> 1000 kg/year per company): Ag, Al-Ox, Fe-Ox, SiO2, TiO2, and ZnO. The median reported quantity of handled nanoparticles was 100 kg/year. The production of cosmetics, food, paints, powders, and the treatment of surfaces used the largest quantities of these nanoparticles. Generally, the safety measures were found to be higher in powder-based than in liquid-based applications. However, the respondents had many open questions about best practices, which points to the need for rapid development of guidelines and protection strategies

Social network architecture and the maintenance of deleterious cultural traits.

How have changes in communications technology affected the way that misinformation spreads through a population and persists? To what extent do differences in the architecture of social networks affect the spread of misinformation, relative to the rates and rules by which individuals transmit or eliminate different pieces of information (cultural traits)? Here, we use analytical models and individual-based simulations to study how a 'cultural load' of misinformation can be maintained in a population under a balance between social transmission and selective elimination of cultural traits with low intrinsic value. While considerable research has explored how network architecture affects percolation processes, we find that the relative rates at which individuals transmit or eliminate traits can have much more profound impacts on the cultural load than differences in network architecture. In particular, the cultural load is insensitive to correlations between an individual's network degree and rate of elimination when these quantities vary among individuals. Taken together, these results suggest that changes in communications technology may have influenced cultural evolution more strongly through changes in the amount of information flow, rather than the details of who is connected to whom.

Implementing statistical learning methods through Bayesian networks. Part 1: a guide to Bayesian parameter estimation using forensic science data

As a thorough aggregation of probability and graph theory, Bayesian networks currently enjoy widespread interest as a means for studying factors that affect the coherent evaluation of scientific evidence in forensic science. Paper I of this series of papers intends to contribute to the discussion of Bayesian networks as a framework that is helpful for both illustrating and implementing statistical procedures that are commonly employed for the study of uncertainties (e.g. the estimation of unknown quantities). While the respective statistical procedures are widely described in literature, the primary aim of this paper is to offer an essentially non-technical introduction on how interested readers may use these analytical approaches - with the help of Bayesian networks - for processing their own forensic science data. Attention is mainly drawn to the structure and underlying rationale of a series of basic and context-independent network fragments that users may incorporate as building blocs while constructing larger inference models. As an example of how this may be done, the proposed concepts will be used in a second paper (Part II) for specifying graphical probability networks whose purpose is to assist forensic scientists in the evaluation of scientific evidence encountered in the context of forensic document examination (i.e. results of the analysis of black toners present on printed or copied documents).

Neurotoxicity of dibutyltin in aggregating brain cell cultures.

Dibutyltin (DBT) compounds are used primarily as stabilizers for polyvinyl chloride (PVC) plastics. Small quantities can be released from PVC containers into stored liquids. The neurotoxicological potential of DBT was tested in aggregating brain cell cultures after a 10-day treatment with concentrations ranging from 10(-10) to 10(-6)m, either during an early developmental period, or during a phase of advanced maturation. Changes in protein content, DNA labelling and cell type-specific enzyme activities were measured as end points. DBT caused general cytotoxicity at 10(-6)m in both immature and differentiated cultures. At 10(-7)m, it affected the myelin content and the cholinergic neurons in both states of maturation, while GABAergic neurons remained unchanged. Astrocyte and oligodendrocyte markers were diminished at 10(-7)m of DBT exclusively in immature cultures. DBT uptake by undifferentiated and differentiated cells was similar at this concentration. Whereas trimethyltin (TMT) is known to induce gliosis and triethyltin (TET) to cause demyelination and affect GABAergic neurons, DBT appeared to be more toxic than TMT, and to present a distinct toxicological pattern.

Quantifying Accuracy Improvement in Sets of Pooled Judgments: Does Dialectical Bootstrapping Work?

Galton (1907) first demonstrated the "wisdom of crowds" phenomenon by averaging independent estimates of unknown quantities given by many individuals. Herzog and Hertwig (2009; hereafter H&H in Psychological Science) showed that individuals' own estimates can be improved by asking them to make two estimates at separate times and averaging them. H&H claimed to observe far greater improvement in accuracy when participants received "dialectical" instructions to consider why their first estimate might be wrong before making their second estimates than when they received standard instructions. We reanalyzed H&H's data using measures of accuracy that are unrelated to the frequency of identical first and second responses and found that participants in both conditions improved their accuracy to an equal degree.

Implementation of Benchmark Project Recommendations for Iowa DOT Offices of Construction, Addendum to HR-381, 1996

This report describes the continuation of the development of performance measures for the Iowa Department of Transportation (DOT) Offices of Construction. Those offices are responsible for administering transportation construction projects for the Iowa DOT. Researchers worked closely with the Benchmark Steering Team which was formed during Phase I of this project and is composed of representatives of the Offices of Construction. The research team conducted a second survey of Offices of Construction personnel, interviewed numerous members of the Offices and continued to work to improve the eight key processes identified during Phase I of this research. The eight key processes include Inspection of Work, Resolution of Technical Issues, Documentation of Work Progress and Pay Quantities, Employee Training and Development, Continuous Feedback for Improved Contract Documents, Provide Safe Traffic Control, External/Public Communication, and Providing Pre-Letting Information. Three to four measurements were specified for each key process. Many of these measurements required opinion surveys of employees, contractors, and others. During Phase II, researchers concentrated on conducting surveys, interviewing respondents to improve future surveys, and facilitating Benchmark Steering Team monthly meetings. Much effort was placed on using the information collected during the first year's research to improve the effectiveness and efficiency of the Offices of Construction. The results from Process Improvement Teams that studied Traffic Control and Resolution of Technical Issues were used to improve operations.