Search

Children's perception of the critical (upper) limit of their stepping affordances, was tested at 6, 8, and 10 years of age for stepping onto (SONmax in Experiment I) and over (SOVmax in Experiment II) obstacles. Warren's (1984) proposition (similarity hypothesis) that adults perceive SONmax to be .88 of leg length (L) because the geometry of adults' legs is invariant over varying height was extended to varying height due to growth. Because the geometry of children's legs is both invariant over growth between 6 and 10 years and identical to adults, we predicted that children should both accurately perceive their critical limit and perceive it to be .88L. Experiment I confirmed these predictions and Experiment II demonstrated that children differentiate between the two stepping affordances. The similarity hypothesis is further supported by the fact that age does not interact with either observers' mean accuracy over conditions or variability within observers. This stable performance is interpreted ...

Restricting the functional integral to the Gribov region $\Omega$ leads to a deep modification of the behavior of Euclidean Yang-Mills theories in the infrared region. For example, a gluon propagator of the Gribov type, $\frac{k^2}{k^4+{\hat \gamma}^4}$, can be viewed as a propagating pair of unphysical modes, called here $i$-particles, with complex masses $\pm i{\hat \gamma}^2$. From this viewpoint, gluons are unphysical and one can see them as being confined. We introduce a simple toy model describing how a suitable set of composite operators can be constructed out of $i$-particles whose correlation functions exhibit only real branch cuts, with associated positive spectral density. These composite operators can thus be called physical and are the toy analogy of glueballs in the Gribov-Zwanziger theory., Comment: 35 pages, 10 .pdf figures. v2: version accepted for publication in Physical Review D

Synopsis The study of the behaviour of perfume ingredients in emulsions involves several technological problems. Recently, the scientific and practical validity of the parameter known as ‘hydrophilic value’ Kd (according to Bonadeo) was recognised; it relates to the behaviour of fatty materials in emulsions. The purpose of this research was to verify the reliability of the above parameter as applied to perfume ingredients. From the experimental results it is possible to establish a mathematical relationship between Kd and the ‘required emulsification value’ (HLBr) of the aromatics used in perfuming cosmetics and toiletries. From the Kd value it is possible to calculate the critical limit of the water phase (CLWP) concerning the single ingredients of a perfume compound. These parameters are particularly important in predicting the optimal behaviour of perfumes in the chemical-physical balance of emulsions, with which are connected the principal parameters of the chemical and olfactive stability. Thus, in practice, it has been demonstrated that the perfumed substances behave as, and can be considered as, other fatty bodies forming the fatty phase of emulsions. Hydrophilie des huiles essentielles

Hazard Analysis and Critical Control Points (HACCP) is a system based on prevention and analysis of hazards and contributes to provision of health safety of food. The requirement for establishing the HACCP system in a food-processing organisation is given by the Czech Republic{\crq}s legislation as well as by the legislation of European Union, and is in accord with Codex Alimentarius (Food code). The baccalaureate thesis includes theoretical findings on the HACCP system and the analysis of hazards, as well as practical part, inclusive of introducing the HACCP system of a specific food-processing organisation {--} Dr. Oetker, s.r.o. The organisation must have established HACCP documentation, conducted hazards analysis, stipulated the critical control points (CCP) and corrective provisions upon exceeding the critical limits. The system is continuously being checked on the entire process of production. The HACCP system is subject to certification, the international standard ISO 22000 of food safety management system. HACCP, as a part of organization{\crq}s food safety policy, contributes to excluding hazardous factors from the process of food production and thereby also prevents exposure of the consumers.

The behavior of vehicle following model was investigated in the paper from the point of view of non-linear dynamics. When the mean density of the traffic flow exceeds some critical limit the formation of stable dissipative structures can be observed. This pattern-producing system shows further properties typical of complex system as well.

A device perspective is applied to the issue of critical layer thickness and the impact of strain relaxation on electrical characteristics. We have fabricated In x Al 1−x As/n + −In 0.53 Ga 0.47 As HFETs with InAs mole fractions in the 300 A thick In x Al 1−x As insulator of x =0.52 (lattice-matching), 0.48, 0.40, and 0.30. The x =0.40 and 0.30 samples, with thicknesses greater than the critical limit, show unidirectional surface ridges that reveal misfit dislocations at the In x Al 1−x As/In 0.53 Ga 0.47 As hetero-interface. Dislocations are found to severely degrade the performance of devices when the current in the device flows perpendicular to them. Excellent HFETs were obtained with current flow parallel to the surface ridges for x =0.40, in spite of the unequivocal evidence of dislocations in the devices.

Over 200 samples of cow's milk have been analysed for dioxins in a survey on the occurrence of dioxins in milk from the vicinity of municipal waste incinerators (MSWs) and other potential dioxin sources in The Netherlands. Levels in milk were found to vary considerably with time, depending on emission rates, the direction and distance to the source and the feeding and housing of cows. Highest levels of up to 13.5 pg TEQ/g of milk fat were found in the Lickebaert area and Zaandam near two incinerators with highest emission rates. The background level ranged between 0.7 and 2.5 pg TEQ/g of milk fat. Levels in winter were comparable to those found in summer and, in some areas, even higher, when cows were fed with hay and silage harvested on the same farm. After the closure of the MSW in Zaandam, cow's milk from neighbouring farms showed a significant decrease in dioxin levels to below the critical limit of 6 pg TEQ/g of milk fat. Dioxin levels in the vicinity of a metal reclamation plant were comparable to those in milk from the vicinity of a MSW with moderate emissions. Differences were observed in the ratio PCDF/PCDD, which was higher in milk near the metal reclamation plant. Principal component analysis has been applied on a large data set of patterns of the 2,3,7,8-chlorine substituted PCDDs and PCDFs in cow's milk. This technique has proved to be useful for distinguishing and identification of sources on the basis of the isomer pattern in milk.

Publisher Summary This chapter discusses the prediction of loss of corrosion resistance in austenitic stainless steels. Austenitic stainless steels contain a combination of Cr and Ni, which makes them fully austenitic under most practical conditions. The Cr content is usually about 18 wt% or higher, which is well above the critical limit for corrosion resistance, about 12 wt% Cr. An accurate calculation of the formation of the depleted zone would require a detailed consideration of the diffusion-controlled growth of the C-rich carbide. However, a rough estimate can be made from the thermodynamic information on the Fe–Cr–Ni–C system. The chapter presents the calculations that were carried out using the Thermo-Calc databank. It has a special feature for automatic calculation of diagrams involving two different but related equilibria in each step. For the calculations presented in the chapter, information on austenite and M23C6 were used.

We are interested in strain accumulation process in polymeric materials when exposed to periodic (cyclic) loading. Within each loading cycle material undergoes a combination of the creep and relaxation process. At certain conditions the retardation process between two loading cycles cannot be fully completed. Consequently strain starts to accumulate, which leads to hardening of the material and ultimately to the failure of polymeric product. Taking into consideration the importance of the mechanical spectrum of polymeric material for predicting durability of dynamically loaded polymeric products, [1], we present the analysis of the effect of the “shape” of material time‐dependent properties, expressed with the mechanical spectrum, on the process of strain accumulation under periodically applied loading. We observe, that spectrum shape defines the intensity and the magnitude of strain accumulation process. For certain type of material the accumulated strain will almost certainly lead to the failure of the product, while material with different time‐dependent characteristics will not experience the critical limit of accumulated strain that would cause failure.

We consider the three-dimensional randomly diluted Ising model and study the critical behavior of the static and dynamic spin-spin correlation functions (static and dynamic structure factors) at the paramagnetic-ferromagnetic transition in the high-temperature phase. We consider a purely relaxational dynamics without conservation laws, the so-called model A. We present Monte Carlo simulations and perturbative field-theoretical calculations. While the critical behavior of the static structure factor is quite similar to that occurring in pure Ising systems, the dynamic structure factor shows a substantially different critical behavior. In particular, the dynamic correlation function shows a large-time decay rate which is momentum independent. This effect is not related to the presence of the Griffiths tail, which is expected to be irrelevant in the critical limit, but rather to the breaking of translational invariance, which occurs for any sample and which, at the critical point, is not recovered even after the disorder average., Comment: 43 pages

Monodromy fields on ℤ2 are a family of lattice fields in two dimensions which are a natural generalization of the two dimensional Ising field occurring in theC*-algebra approach to Statistical Mechanics. A criterion for the critical limit one point correlation of the monodromy field σa(M) at a ∈ ℤ2, $$\mathop {\lim }\limits_{s \uparrow 1} \left\langle {\sigma _a (M)} \right\rangle ,$$ is deduced for matrices M ∈ GL(p,ℂ) having non-negative eigenvalues.

It is shown that the integral quasipotential Logunov-Tavkhelidze and Kadyshevskii equations with local —in Lobachevskii momentum space — quasipotentials, the transforms of which are even rational functions of r in relativistic configurational space, may be reduced to a Sturm-Liouville problem in the case of unit orbital momentum. In the critical limit, when the bound-state mass is zero, accurate wave functions are obtained.

Results of accelerated tests for screening potentially reactive concrete aggregates are presented. The tests were performed using a newly developed, computer-controlled Double LVDT instrumentation. A statistical analysis of data obtained from the test indicates that high and significant correlations exist between the accelerated test and the standard tests employed in the study. From the relationships between the accelerated test and the standard tests, critical limits of expansion were established for the former. Expansions in hot (80°C) IN NaOH solution of 0.17% after 12 days and 0.33% after 24 days are considered excessive for alkali-silica reactive rocks; for alkali-carbonate reactive rocks, the critical limit is 0.16% after 24 days.

Introducción. El mercado actual de platos preparados pone gran esfuerzo en ofrecer productos que obtengan el favor del consumidor, lo que implica el desarrollo de sistemas que redunden en calidad nutricional e inocuidad. En algunos países, principalmente en aquellos en los que desaparece el concepto de "ama de casa" la proliferación de platos preparados y de alimentos procesados de pollo es notable, dentro de los cuales, la carne de pollo es un excelente alimento tanto desde el punto de vista de las técnicas de producción como de la fisiología de la nutrición. Objetivo. Determinar peligros, PCC, LC y medidas preventivas en la línea de producción de pechuga desmechada enlatada. Materiales y métodos. Se realizó un estudio descriptivo de un caso típico de la producción de pechuga de pollo desmechada enlatada en donde cada etapa de la sección fue sometida a estudio y se aplicaron los siete principios del sistema HACCP. Resultados. Como resultados principales se determinaron tres puntos críticos de control (PCC) para las etapas de recepción de materia prima, sellado y tratamiento térmico; se establecieron límites críticos para los PCC, las medidas correctivas y el sistema de monitoreo de los PCC. Conclusión. El proceso de documentación y posterior puesta en marcha del plan HACCP lleva a la empresa a mejorar aspectos tecnológicos que redundan en el aseguramiento de la calidad del producto y a su vez establecen la confianza que debe existir entre el consumidor y el producto en particular, así como de los demás productos de la empresa. Introduction. The current market of prepared meals make a great emphasis on offering products the consumers really like, and this requires the development of systems that provide nutritional quality and innocuity. In some countries, especially those in which the concept of housewife disappears, the number of prepared meals and processed foods from chicken is remarkable. Among them, chicken meat is an excellent nutritional source from the technical point of view due to its characteristics of production, and also from the nutritional physiology. Objective. To determine perils, PCC, LC and prevention measurements in the production line of smashed chicken breast available in cans. Materials and methods. A descriptive study of a typical case in canned smashed chicken breast was made, and each stage of the section was submitted to study and the seven principles of the HACCP system were applied. Results. Three critical points of control (PCC in Spanish) were determined for the stages of reception of raw material, sealing and thermal treatment. Critical limits for the PCC were established, and also the corrective measurements and the monitoring system for those PCCs. Conclusion. The documentation process and the start of the HACCP plan, helps the enterprise to improve the technological aspects that accurate the quality of the product and, at the same time, establish the trust required between producer and consumer. Besides, it improves the other products from the enterprise.

We determine which are the mechanisms accelerating the surface of single stars during the Main Sequence evolution. We have computed 112 stellar models of four different initial masses between 3 and 60 M_sun, at four different metallicities between 0 and 0.020, and with seven different values of the ratio Omega/Omega_crit between 0.1 and 0.99. For all the models, computations were performed until either the end of the Main Sequence evolution or the reaching of the critical limit. The evolution of surface velocities during the Main Sequence lifetime results from an interplay between meridional circulation (bringing angular momentum to the surface) and mass loss by stellar winds (removing it). The dependence on metallicity of these two mechanisms plays a key role in determining for each metallicity, a limiting range of initial masses (spectral types) for stars able to reach or at least approach the critical limit. Present models predict a higher frequency of fast rotating stars in clusters with ages between 10 and 25 Myr. This is the range of ages where most of Be stars are observed., Comment: 20 pages, 22 figures, accepted for publication in A&A

Research about evaluation and implementation HACCP document of frozen tuna saku product Focus at HACCP document evaluation, used descriptive qualitative method and quantitative test from level histamine value in fresh tuna was received and pathogen bacterium at fresh water and also presentage of level improve with audited result of implementation from revised HACCP document. Revised of HACCP document frozen tuna saku, to show two critical control point the first at phase recieving fresh tuna as raw material with a purpose to histamnie eliminated, histamine value representing hazard potencial by applying critical limit control at refrigeration process use ice so that center of fish temperature remain at range 0- 4,4°C, and second critical control point in the butchering or dehaeding phase with a purpose to pathogen bacteria Escerichia coli, Coliform, and Salmonella spp eliminated which possible could happened from used fresh water without treatment. Audit result of revised HACCP document of frozen tuna saku implementation quantitatively its at level improve about 89% compared to HACCP document before revised that is still at level 62%, this level matter is make-up of in the case of document implementation revised by HACCP team. Level improve have to monitoring implementation HACCP document to make assurance of quality and security from frozen tuna saku, that has been export product. Keywords: audit, critical control point(s), critical limit, frozen tuna saku, HACCP, histamine

In many cases bioavailability and toxicity of cationic metals in soils is determined by the free metal ion (FMI) activity in soil solution. Recently methods were developed that relate biological effects to FMI activity. The use, validation and further development of such approaches require determination of FMI activities in soil. FMI activity determination is, however, prone to methodological and analytical problems. Therefore we tested two different analytical methods: Cu activity measurement with (1) an ion selective electrode (ISE) and (2) a Donnan Membrane Technique (DMT). In addition we used computational methods to predict copper activity: (1) using speciation models WHAM VI and NICA and (2) using transfer functions (TF) which relate metal partitioning to soil properties. Methods were tested on soils contaminated with Cu by a Cu-Ni smelter. Emphasis was given to the organic horizon because of its importance for soil life and because FMI data for this horizon are lacking. Results show good agreement between Cu activities measured with Cu-ISE and DMT for the high Cu concentration range. The use of ISE method was limited to solutions with total Cu concentrations above 10¿6 mol¿L¿1, below this concentration the method gave unreliable results. The DMT technique was limited by the detection limit of the ICP-MS used (10¿8 mol¿L¿1). Deviation between models (WHAM, NICA, and TF) and measurements are within uncertainties due to different analytical techniques and the spatial variation found in soils.

A pot experiment was conducted at glasshouse of Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, with 18 extensively cultivated soils of Bangladesh to evaluate extractable P and to determine its critical limit for mustard. The available P contents in soils were extracted by four methods viz. Olsen, Hunter, Bray II and Nelson. The mean extractable P in soils was found to be in the order of Nelson > Bray 11 > Hunter > Olsen. Considerable variation was found in the amount of extractable P depending on the soils and extractants used. Dry matter yields were remarkably increased with addition of increasing rate of phosphatic fertilizer and the soil having low extractable P responded better to applied P. All extractable P except Nelson correlated positively and significantly with relative yield. Extractable P of all extractants except Nelson was positively and significantly correlated with P content " of mustard in all and low pH soils. Phosphorus uptake was also positively correlated with all extractants in all and low pH soils. The critical limits of soil extractable P for mustard for Olsen, Hunter, Bray II and Nelson method were estimated as 8.6, 9.5, 14.5 and 20.0 ppm (Graphical method) and 10.5, 12.5, 16.5, and 16.5 ppm (Statistical method) respectively. Based on B2 value it may be-concluded that Nelson method of P extraction was found to be the best method for estimating P response of mustard.

We report the results of measurements of the dc susceptibility and the $^{23}\mathrm{N}\mathrm{a}$-NMR response of ${\mathrm{N}\mathrm{a}}_{2}{\mathrm{V}}_{3}{\mathrm{O}}_{7}$, a recently synthesized, nonmetallic low dimensional spin system. Our results indicate that, upon reducing the temperature to below 100 K, the ${\mathrm{V}}^{4+}$ moments are gradually quenched, leaving only one moment out of nine active. The NMR data reveal a phase transition at very low temperatures. With decreasing applied field $H$, the critical temperature shifts towards $T=0\text{ }\mathrm{K}$, suggesting that ${\mathrm{N}\mathrm{a}}_{2}{\mathrm{V}}_{3}{\mathrm{O}}_{7}$ may be regarded as an insulator reaching a quantum critical point at $H=0$.

Some cubic equations of state accurately predict P-T behavior near the critical point, but do not properly predict density or volume. Calculation of P-T coexistence curves may be computationally complicated. Improvement of properly predictions and decrease in computational effort may result from studying predicted limiting behavior near the critical point. This was done for the Soave-Redlich-Kwong equation of state.

SI Engine knock is caused by autoignition in the unburnt part of the mixture (end-gas) ahead of the propagating flame. Autoignition of the end-gas occurs when the temperature and pressure exceeds a critical limit when comparatively slow reactions - releasing moderate amounts of heat - transform into ignition and rapid heat release. In this paper the difference in the heat released in the end-gas - by low temperature chemistry - between lean, rich, stochiometric, and stoichiometric mixtures diluted with cooled EGR was examined by measuring the temperature in the end-gas with Dual Broadband Rotational CARS. The measured temperature history was compared with an isentropic temperature calculated from the cylinder pressure trace. The experimentally obtained values for knock onset were compared with results from a two-zone thermodynamic model including detailed chemistry modelling of the end-gas reactions. (Less)

Tailoring electronic and optical properties of self-assembled InAs quantum dots (QDs) is a critical limit for the design of several QD-based optoelectronic devices operating in the telecom frequency range. We describe how a fine control of the strain-induced surface kinetics during the growth of vertically-stacked multiple layers of QDs allow to engineer their self organization process. Most noticeably, the present study shows that the underlying strain field induced along a QD stack can be modulated and controlled by time-dependent intermixing and segregation effects occurring after capping with GaAs spacer. This leads to a drastic increase of TM/TE polarization ratio of emitted light, not accessible from the conventional growth parameters. Our detailed experimental measurements supported by comprehensive multi-million atom simulations of strain, electronic, and optical properties, provide in-depth analysis of the grown QD samples leading us to depict a clear picture on atomic scale phenomena affecting the proposed growth dynamics and consequent QD polarization response., Accepted for publication in IOP Nanotechnology

The recently found non-critical open string theories is reviewed. These open strings, noncommutative open string theories (NCOS), arise as consistent quantum theories describing the low energy theory of D-branes in a background electric B-field in the critical limit. Focusing on the D3-brane case, we construct the most general (3+1) NCOS, which is described by four parameters. We study S and T -dualities of these theories and argue the existence of a U-duality group., Comment: 10 pages, no figures, The invited talk, presented in the conference "Brane New World and Noncommutative Geometry", Torino, Villa Gualino,(Italy) October, 2000

Following injury, bone has the ability to regenerate itself to a form and function nearly indistinguishable from the pre-injury state. However, if the injury is beyond a critical limit, recovery will not occur without therapeutic interventions. Autografts and implants with banked bone continue as the treatments of choice, although each exhibits limitations and liabilities. Alternatives have included the utilization of bone-graft substitutes that may incorporate bone derivatives and soluble signaling molecules such as mitogens and morphogens. In addition, an evolving treatment modality, gene therapy, offers an exciting avenue for bone regeneration. This review presents some of the current concepts for developing a rational gene therapy approach in bone regeneration.

Publisher Summary This chapter discusses the characterization of antioxidative homeostasis by means of chemiluminescent technique. The state of antioxidative homeostasis can be made based on the measurement of antioxidative reserves in a biological substrate and the extent of its oxidative damage. For oxidative damage to occur, a local decrease in antioxidative factors under a critical limit is the cause for subsequent pathological events. The centrally determined antioxidative capacity of water (ACW) reflects the reaction of the organism toward these local processes. Isolated ACW measurements yield information on the actual antioxidant concentration but do not demonstrate whether their concentration is sufficient under the given circumstances. An approach based on correcting the concentration of antioxidative vitamins that deviate from normal levels appears somewhat promising. Clinically relevant approaches involve quality, dosage, and timing of an adequate effect on antioxidative homeostasis. These can be determined by systematic investigation of the antioxidative capacity of blood plasma with particular emphasis on vitamin C as one of the biologically most relevant components of the water-soluble portion of ACW or vitamin E as the respective lipid-soluble antioxidant, together with hydrogen peroxidestimulated chemiluminescence.

In the autumn of 1995, national lake surveys were conducted in the Nordic countries. The surveys were co-ordinated with respect to lake selection strategy, analytical methods, sampling techniques and sampling period. The 11 heavy metals investigated in nearly 3000 lakes show in general low values and distinct geograhical patterns. Direct and indirect influence of long-range transported air pollution is the major important factor for distribution of Pb, Cd, Zn and also to a certain degree Co. TOC-levels in lakes are important for Fe and Mn but also to a certain degree As, Cr and V. Bedrock geology is the major controlling factor for Cu and Ni, with exception of areas around the smelters at Kola, where the Cu and Ni concentrations in lakes are very high. Bedrock and overburden geology is also an important factor for controlling the concentration levels of As, Co, Cr and V. The results indicate that heavy metal pollution in lakes is a minor ecological problem on a regional sclae in the Nordic contries. Certain areas in particular in southern Norway and Sweden however, are affected by influence of long-range transport leading to increase in Pb, Cd and Zn in lakes above limits set by environmental authorities. Since aquatic biota in these areas already is under stress due to effects of acid rain, this may be an important environmental problem. Hg is not included in the Nordic Lake Survey, but from other work indicates that Hg is a significant environmental problem in many lakes, in southern Finland and Sweden. Nordisk ministerråd (NMR)

An investigation was undertaken to identify the extractability of P through different extractants and to determine the critical limits of P for wheat. The study was made with five extractants in sixteen selected soils of Bangladesh. The amount of extractable P varied markedly depending on the soils and extractants used. Although the ability of P extraction was different for different extractants, their trends of P displacement from soil into solution were mostly similar. All the extractants used in this study correlated well with each other. The application of P encouraged plant growth with the effect of P being large with P fertilization up to 100 mg kg-1. A critical limit of extractable P for wheat was determined by two approaches: graphical and statistical for indicating that below this level of soil P an economic crop response is expected.

It is recognised that the development of new alloys requires the commitment of increasingly large amounts of money and time which few corporations can these days afford. Techniques for short-cutting the development path are needed, e.g. predictive models. Two such methods are presented here for pre-determining alloy stability and strength. The pursuit of this and similar approaches should help to minimise the expense, and time, incurred in manufacturing and testing many unsuccessful alloy formulations. New alloys are still needed with property combinations which have yet to be realised. critical electron vacancy or “N,” value is determined for an alloy, below which it is judged stable over a set time and temperature. The problem with this system however is that a unique critical limit has to be established for each alloy that is assessed. This calculation is continually being refined with regard to the compositions of the various phases. More recently a modified approach involving the “d-electrons concept” (3) for SC alloy design has been extended to include also a measure of the bond strength of the alloying elements (4). In this way, the relative stability of an alloy could be displayed on a map, but the boundaries remain undefined.

The Food Safety and Inspection Service (FSIS), an agency of the US Department of Agriculture, is responsible for ensuring that meat, poultry and meat and poultry products in interstate and foreign commerce are safe, wholesome, not adulterated and accurately labeled. FSIS administers and enforces the Federal Meat Inspection Act, the Poultry Products Inspection Act and the regulations by which these laws are implemented. Federal inspectors enforce the inspection laws in about 6500 meat and poultry plants. Livestock and poultry are inspected before slaughter and their carcasses and organs are inspected again after slaughter. Meat and poultry products are inspected during processing, handling and packing. Inspectors have authority to stop any aspect of an operation and demand correction of any deficiency that they find may adversely affect the safety and wholesomeness of the product.

Since the early eighties, effects of acid atmospheric deposion have received much attention in the Netherlands. Effects of elevated S and N deposition on soil solution chemistry is mainly manifested by increased concentrations of Al associated with increased concentrations of SO4 and NO3. Presumed critical Al concentrations (0.2 molc m−1) and Al/Ca ratios (1.0 mol mol−1) are generally exceeded below 20 cm soil depth. There is also ample circumstantial evidence that elevated N deposion during the last decades affected the forest nutrient status and caused large changes in forest vegetation. About half of the Dutch forests have foliar N contents exceeding a critical limit (1.8%). Field evidence for a relationship between soil acidification and nutrient imbalances in the soil and the foliage on one hand and the vitality of forests (mainly expressed by defoliation class) on the other hand is, however, lacking. This result implies that an exceedance of critical acid loads, based on critical Al concentrations and Al/Ca ratios observed experiments in relation to effects on root (uptake), do not imply visible effects or even the dieback of forests.

The Vosges mountains (North-East France) have been exposed to acid precipitation since the beginning of the industrialized era (Kreiser et al. 1995) but it is only recently that the existence of acidified streams became apparent (Massabuau et al. 1987). Subsequently, a preliminary overview of extent and location of the surface water acidification in the massif was reported by Probst et al. (1990): 15 acidified and fishless streams among 39 sampled streams were discovered. More recently, in an exhaustive survey of 600 Vosges mountain streams, Party et al. (1993) detected 53 acidified streams (pH≤5.6).

One hundred and ninety-seven neonates were screened within 24 hours after birth by a tricolored mid-arm circumference (MAC) measuring tape with a borderline yellow-zone between 7.5 cm and 8.5 cm and two peripheral zones, red and green beyond 7.5 cm and 8.5 cm respectively. All of the neonates identified by red-zone had birth weight less than 1500 g. Majority (89.7%) of neonates identified by yellow-zone had birth weight between 1500 g and 2000 g, but only a small (10.3%) number of neonates had birth weight more than 2000 g. A very large proportion of neonates identified by green-zone had birth weight more than 2000 g (98.8% vs 1.2% weighed less than 2000 g at birth). The sensitivity and specificity of MAC critical limit 8.5 cm identifying neonate below 2000 g were 93.7% and 98.2% respectively. It was not worthy in this study to calculate the sensitivity and specificity of the critical limit of 7.5 cm for MAC to identify neonates below 1500 g because of the very small sample size. But, this simple MAC measuring tape can be used by field worker for easy assessment of low birth weight neonates.

Fission cross-sections of 119Sn and 209Bi induced by negative pions of two energies 500 and 672 MeV were measured using a CR-39 nuclear track detector. Target-detector stacks were exposed to pion beams at the Brookhaven National Laboratory (USA). Measurement results are compared with the corresponding calculations using the computer code CEM95. Agreement between measurements and calculations is fairly good for the 209Bi target nuclei whereas it is poor for 119Sn at both investigated energies of 500 and 672 MeV. Fission cross-section results of 119Sn and 209Bi are explained using the equilibrium properties of these nuclides including nuclear electric quadrupole moments which determine the shapes of nuclei. A logarithmic dependence of fission cross-section on Z2/A is observed for the above-mentioned reactions and a critical limit of Z2/A is identified with the value of 30 which divides the curve of σf versus Z2/A into two regimes, one with weak dependence and the other with strong dependence.

Implementing the HACCP system in a food company or manufacturing facility requires knowledge of the system, commitment, planning, resources and follow-through. Although the knowledge and technology of the HACCP system are important prerequisites, implementation is accomplished by the more conventional methods that organizations use for establishing new procedures and processes. One must not overlook the fact that people establish new systems and that organizational skills are a most important element of this type of endeavor. The following parts of this chapter discuss organizational elements of implementing HACCP.

The activity of monitoring within a HACCP system is essential to the system’s success. In order to establish and effectively conduct monitoring procedures, the questions what, why, how, where, who and when must be answered.

Records are written evidence through which an act is documented. The act of keeping records assures that this written evidence is available for review and is maintained for the required length of time.

To achieve maximum success in food product protection, HACCP programs should be restricted to safety. HACCP Critical Control Points (CCPs) should only be used to control those points in a food manufacturing process where lack of control will likely result in the development of a potential safety hazard. They should not be used to control nonhazardous situations. Too many control points to monitor, by inclusion of nonhazardous points, will dilute the focus on safety. With manufacturing resources to monitor HACCP CCPs already limited in most cases, inclusion of nonhazardous points will result in the personnel not understanding which are the truly critical points. The end result of such a disparate program will be that nothing is being adequately monitored. There will then be no assurance that the product being released meets all the safety requirements; a potential hazard may be delivered to consumers. Nonsafety related monitoring procedures should instead be part of a standard quality assurance program.

Defatted coconut flour obtained from the whitish kernel residue left after the extraction of virgin coconut oil has potential application in high protein-fiber enriched food products. A study was conducted to investigate the use of defatted coconut flour in the preparation of fiber-enriched biscuits. In this, wheat flour was fortified with defatted coconut flour in varying proportions (w/w, 0, 10, 20, 30, 40, 50, 60, and 70%) to prepare a series of blends for biscuit dough. Biscuits samples prepared according to a standard recipe were evaluated by a 36-member semi-trained panel using a 7-point hedonic scale to determine the critical limit of defatted coconut flour substitution in wheat flour for acceptable quality biscuits. Results showed that defatted coconut flour could be used to substitute wheat flour up to a level of 40% without affecting the overall quality. At this level, the dietary fiber content of the biscuit was found to increase by about 10 times. Although biscuit samples showed good acceptability at the beginning, their keeping quality decreased with the increasing level of defatted coconut flour in the biscuit formulation.

The London limit of the Lawrence-Doniach theory is expressed in terms of the local magnetic field and from this formulation a continuum model is derived, valid when the layers act coherently. The effects of the layered structure are seen at local variations of the magnetic field of the order of the inter-layer separation and at high values of the Josephson supercurrent, near its critical limit.

Automated blood counts from a patient with Waldenström's macroglobulinaemia repeatedly failed critical limit standards set for mean cell haemoglobin concentration and mean cell haemoglobin. Haemoglobin estimation was higher than that suggested by clinical examination, symptoms, and the spun haematocrit. This was found to be due to an interaction between the Coulter lysing agent and monomeric IgM paraprotein in the patient's plasma, creating a precipitate which was optically dense at 525 nm.

A critical limit of 3–3.5 Bark has been reported for the ‘‘spectral center of gravity’’ effect between the second and third formants (F2 and F3) and is assumed to correspond to a perceptually natural boundary [A. K. Syrdal and H. S. Gopal, J. Acoust. Soc. Am. 79, 1086–1100 (1986)]. This hypothesis was tested for both the [+/−back] and [+/−coronal] distinctions in English vowels. Subjects identified two sets of three‐formant synthetic vowels which varied orthogonally in F2 and F3 and ranged between /ᴜ/–/ɪ/ ([+/−back]) or /ɝ/–/ᴜ/ ([+/−coronal]). For the /ᴜ/–/ɪ/ distinction, a boundary shift was observed solely as a function of F2, ruling out an invariant F3–F2 boundary. For the /ɝ/–/ᴜ/ series, both F2 and F3 influenced boundary location. There was a relatively stable F3–F2 boundary for the mean identification responses in this case, but it occurred at less than the predicted 3–3.5 Bark difference. Follow‐up results will also be presented. [Work supported by NIDCD.]

We have studied the efiect of non-thermal electrons on the structure of a shock wave in a magnetised plasma. Using the reductive perturbation technique we have derived the Zakharov{Kuznetsov equation, and also the modifled version of it in the critical limit. The structure of the shock wave is then analysed as a function of the parameter fl, which measures the deviation from the thermalised state. The corresponding behaviour of the maxima of the shock wave and its velocites are depicted graphically. Both comprehensive and rarefactive shocks are seen to be generated.

Oxygen consumption (V02) is normally independent of systemic oxygen delivery (DO2). When DO2 is reduced, the systemic oxygen extraction (ER) increases until a critical limit (DO2crit) is reached below which oxygen consumption (VO2) becomes limited by delivery. Alfentanil is a fentanyl derivative characterized by a rapid onset, and a short duration of action. As alfentanil better blunts the hormonal stress response than fentanyl (1), it has been especially recommended for open heart surgery. However, the precise effects of this agent on the DO2/VO2 relationship have not been defined. This study was performed to determine the effects of alfentanil on tissue 02 extraction capabilities on a model of progressive hemorrhage in 18 mongrel dogs (2).

In Reply.— We have conducted two parallel national surveys of critical limits. One covered a broad cross section of medical institutions and trauma centers, the other, children's hospitals (Table). The table summarizes the use of SI units for representative critical limit tests and gives the factors for conversion of conventional to SI units. 1 These results (from 92 US medical centers and 39 children's hospitals) lead to the following observations: (1) The majority of hospitals used conventional units, (2) electrolytes with simple conversion factors (eg, × 1) were often listed with SI units, (3) some tests introduced recently (eg, free or "ionized" calcium) were listed with SI units, (4) tests with methods traditionally using SI units (eg, ammonia) were listed that way, (5) tests with noninteger conversion factors (eg, glucose and bilirubin) generally were listed with conventional units, and (6) hematology and blood gas tests were listed with conventional

Earlier field experiments have shown that the sandy dome-shaped hills south of Kinshasa are denuded by the combined action of splash and discontinous runoff. The sandy cover of a typical hill becomes progressively finer downhill where the slope is steeper. Laboratory experiments on similar sands demonstrate that splash has a preference for the coarse modal fraction. Simulated disturbed rough laminar runoff exports slightly coarser sands than does splash, even over gentle slopes where the regime is subcritical. But splash leaves the grains over 0.6 mm while discontinuous run-off selects even these for rapid transportation. Study of the transportation rates of both mechanisms conclusively demonstrates that splash creates a coarse lag on the summital sections of the Amba hill but that discontinuous runoff leaves a progressively finer residue, which is being transported, as the slope becomes steeper. Silt is also protected from erosion but it is not known to what extent the creation of a filtration pavement is responsible for this. The critical grain-size limit, below which the relative concentration increased, is 0.215 mm, both in the field and in the laboratory. This critical limit is some-what finer than the median grain-size of the Kalahari sands covering the hilltops and also of the fabricated bimodal sands.