Unmeasured Values Research Articles

An objective and optimal estimation approach to cloud-clearing for infrared sounder measurements

Abstract In order to produce temperature or water vapour profiles from infrared radiance measurements the detection or possible cloud contamination within the field-of-view is required. In most retrieval schemes a correction phase follows so that the inversion algorithm operates on clear column infrared radiances We describe a new sequential objective and optimal filtering scheme aiming at processing radiances, for each infrared measuring channel, to produce a field of cloud-cleared values with sufficiently well-defined statistical properties and error structures. Basically the method uses clear measurements only and treats cloudy data as unmeasured or missing data Simulated values of clear column radiances for HIRS/2 channel 7 are used as a test field. The results presented are retrieval of clear radiance fields from cloudy data sets, each consisting of the test field with instrumental noise added and a cloud mask defining whether each individual field of view is clear or not. Radiances defined as cloudy...

Airway resistance of the posterior nasal pathways in sudden infant death victims

In order to test the hypothesis that infectious swelling of parts of the inner nose causes airway obstruction and is of aetiological significance for sudden infant death (SID), we measured the airway resistances of the prepared posterior nasal pathways of 55 SID victims and 7 infants who died of other causes. About 25% of the SID victims but none of the control cases had strongly elevated nasal resistances; over 4000 kPa.s.m-3 up to unmeasurable values. A histological survey showed that about 50% of the SID cases and only 1 of the control cases exhibited distinct to severe signs of inflammation of the nasal mucous membranes. No correlation was found between nasal resistance and age, sex, body weight, body length, head circumference, or histological findings. We conclude that an elevated nasal resistance plays a role in some SID cases and that SID is rather the result of different processes than a monocausal disease.

NONLINEAR MODEL PREDICTIVE CONTROL

Abstract Nonlinear Model Predictive Control (NMPC), a strategy for constrained, feedback control of nonlinear processes, has been developed. The algorithm uses a simultaneous solution and optimization approach to determine the open-loop optimal manipulated variable trajectory at each sampling instant. Feedback is incorporated via an estimator, which uses process measurements to infer unmeasured state and disturbance values. These are used by the controller to determine the future optimal control policy. This scheme can be used to control processes described by different kinds of models, such as nonlinear ordinary differential/algebraic equations, partial differential/algebraic equations, integra-differential equations and delay equations. The advantages of the proposed NMPC scheme are demonstrated with the start-up of a non-isothermal, non-adiabatic CSTR with an irreversible, first-order reaction. The set-point corresponds to an open-loop unstable steady state. Comparisons have been made with controllers ...

Model Predictive Control of Nonlinear Processes in the Presence of Constraints

Nonlinear Model Predictive Control (NMPC), a strategy for constrained, feedback control of nonlinear processes, has been developed previously by Patwardhan and co-workers (1989). The algorithm uses a simultaneous solution and optimization approach to determine the open-loop optimal manipulated variable trajectory at each sampling instant. Feedback is incorporated via an estimator, which uses process measurements to infer unmeasured state and disturbance values. These are used by the controller to determine the future optimal control policy. The advantages of NMPC were found to be its robustness to modeling error, and its ability to deal with constraints in an explicit manner without appreciable degradation in the quality of control, or speed of response. In the present paper, we study (i) the effect of manipulated variable bounds on robustness, (ii) robustness to error in model structure, and (iii) ability of NMPC to reject unmeasured disturbances. In each instance, comparison is made with a discrete linear controller tuned using the IMC approach.

The Completion of theC-Response Function For Utilization In Exact Inversion Procedures

Summary Exact or analytical methods for the solution of the 1-D magnetotelluric inverse problem require knowledge of the complete c-response function. Unfortunately, in practice, only incomplete and noisy response data are provided at a finite number of discrete frequencies. Consequently, to utilize exact inversion techniques, it is first necessary to complete the response data, a problem which is both ill-posed (unstable) and under determined. In this paper, a rational and consistent procedure is proposed for the reconstruction of the response function, based on the application of the maximum entropy (MAXENT) principle. This procedure extrapolates the given data in such a manner as to be maximally non-committal regarding the unmeasured values of the response. the entropy of the c-response function is derived and this result is then used to obtain the MAXENT extrapolation of the response function for both noiseless and noisy response data. the MAXENT completion of the response is attractive in that it is both physically admissible and optimally smooth in the sense that the resulting response does not exhibit any structure inconsistent with the given data.

Morphological evidence for increased protein synthesis in CNS neurons after soman exposure

Fine structural changes in neurons of the dorsal hippocampus, caudate nucleus, supraoptic nucleus (SON), and ventral horn of the spinal cord of adult male or spayed female cats were studied after single and multiple doses (dose range 1.0–20.0 μg/kg sc) of the organophosphonate, pinacolyl methylphosphonofluoridate (soman). Increases in amounts of rough endoplasmic reticulum (rER) and polyribosomes, proliferation of Golgi complexes, as well as indentations of nuclear membranes occur after single and multiple exposures. The degree of change is dependent on dose, duration of exposure, and time of survival after exposure. The cell organelles affected are essential for protein synthesis and changes in their quantities are morphological indicators for changes in protein synthesis. The data presented in this study suggest an initial increase in protein synthesis after soman exposure, followed by early signs of degeneration. Soman (10 μg/kg iv) inhibition of cholinesterases of whole blood, spinal cord, and caudate nucleus of control and cats from which electrophysiological recordings of Renshaw cell field potentials were taken show significant differences. Moreover, while blood values are unmeasurable, spinal cord and caudate nucleus values are 42.21 and 53.6% those of controls at 30 min after injection and 63.41 and 50.75% those of controls after 240 min, respectively. No differences are noted between Renshaw cell field potentials after treatment and controls. Similarly, no changes in gross behavior are noted after 10 μg/kg sc. Yet, morphological signs of increases in protein synthesis are present. It is concluded that soman induces increased protein synthesis in many areas studied and that this increase is not dependent on inhibition of cholinesterase to a degree that affects gross behavior of evoked potentials from a CNS cholinergic-transmitting synapse—the motoneuron axon collateral and Renshaw cell ( J. C. Eccles, P. Fatt, and K. Koketsu (1954), J. Physiol. 126, 524–562).

Morphological Evidence for Increased Protein Synthesis in CNS Neurons after Soman Exposure

Fine structural changes in neurons of the dorsal hippocampus, caudate nucleus, supraoptic nucleus (SON), and ventral horn of the spinal cord of adult male or spayed female cats were studied after single and multiple doses (dose range 1.0-20.0 micrograms/kg sc) of the organophosphonate, pinacolyl methylphosphonofluoridate (soman). Increases in amounts of rough endoplasmic reticulum (rER) and polyribosomes, proliferation of Golgi complexes, as well as indentations of nuclear membranes occur after single and multiple exposures. The degree of change is dependent on dose, duration of exposure, and time of survival after exposure. The cell organelles affected are essential for protein synthesis and changes in their quantities are morphological indicators for changes in protein synthesis. The data presented in this study suggest an initial increase in protein synthesis after soman exposure, followed by early signs of degeneration. Soman (10 micrograms/kg iv) inhibition of cholinesterases of whole blood, spinal cord, and caudate nucleus of control and cats from which electrophysiological recordings of Renshaw cell field potentials were taken show significant differences. Moreover, while blood values are unmeasurable, spinal cord and caudate nucleus values are 42.21 and 53.6% those of controls at 30 min after injection and 63.41 and 50.75% those of controls after 240 min, respectively. No differences are noted between Renshaw cell field potentials after treatment and controls. Similarly, no changes in gross behavior are noted after 10 micrograms/kg sc. Yet, morphological signs of increases in protein synthesis are present. It is concluded that soman induces increased protein synthesis in many areas studied and that this increase is not dependent on inhibition of cholinesterase to a degree that affects gross behavior of evoked potentials from a CNS cholinergic-transmitting synapse--the motoneuron axon collateral and Renshaw cell (J. C. Eccles, P. Fatt, and K. Koketsu (1954), J. Physiol, 126, 524-562).

Systematic properties of actinide metals

The solid state and thermodynamic properties of the 7th-row metals actinium through einsteinium are reviewed, particularly in terms of new advances since the Asilomar meeting. General properties for all the elements are considered and the individual metals are surveyed for new results as well as for unresolved problems. The thermodynamic properties of the metals thorium through einsteinium are mostly well-established, evcept for the cohesive energy of protactinium. Here some unmeasured values still remain, particularly the high temperature heat capacities. The relation of 5f-electron bonding to 3d element behaviour is discussed in terms of the electronegativities of the elements, and the homologous shift of the metals americium through einsteinium to correspond with the series neodymium to europium is noted. Plutonium is characterived as an actinide trying hard to become a rare earth, and properties of the “transition region” are briefly discussed. A new understanding of f-electron bonding and structure has come from sophisticated calculations showing the effects of internal pressure, spin polarivation energy and spin-orbit coupling. Recent high pressure results for the transplutonium metals shed light on these special materials.

The dependence of double-ionization energies of diatomic neutral species on the atomic ionization energies

The double-ionization energies of several series of diatomic neutral species are determined using measured values of the differences between single- and double-ionization energies. The results are found to be linearly dependent on the differences in the single-ionization energies of the atoms. Previously unmeasured values are predicted from the relationships established.

Federal project evaluation and intangible resources : The Tellico Dam

A model of resource evaluation incorporating reversibility of actions and substitutability for resource services is presented, along with associated decision criteria. The model extends and generalizes the Krutilla—Fisher procedure for evaluating unique resources. The more general technique is used to assess the official analysis of the Tellico Dam project in eastern Tennessee. In terms of measured values, the preservation option is shown to be superior to development only under extreme assumptions. The existence of substantial unmeasured preservation values in the Tellico case strengthens the environmentalist position, however, particularly since net benefits of development are apparently negative.

Studies of visual function and its decay in mice with hereditary retinal degeneration.

Functional implications of mouse hereditary retinal degeneration have been studied at the level of the superior colliculus and visual cortex in the C57BL/6J-le rd strain. On autoradiography at a light-microscopic level, following eye injection with radioactive compounds, central visual structures appeared normal. A slight reduction in ipsilateral retinal projection was probably related to reduced retinal pigmentation associated with the light ear (le) mutation. In recordings from visual cortex and tectum in rd mice older than five months the cells discharged with highly rhythmic maintained activity. This ongoing activity depended on retinal input, since temporary asphyxia of the eye stopped it immediately. The frequency of the rhythm was influenced by the anesthesia. In these older mice no visual receptive fields could be mapped, but in a few tectal recordings it was possible to suppress the maintained activity by diffuse, very intense illumination. As in normal mice, no auditory or somatosensory responses were observed in the visual cortex or upper tectal layers. In recordings from tectum before the age of three weeks retinotopic topography and receptive fields were normal. By day 24 no receptive fields could be recorded from parts of the tectum representing the central 90--100 degrees of the visual field, whereas within a peripheral ring responses were still roughly normal under photopic conditions. Over the following four months these peripheral responses faded away slowly. Incremental thresholds, especially in the scotopic range, were elevated, rising slowly to unmeasurable values. Similarly during dark adaptation the thresholds fell to values several log units above those reached in normal mice; these values of dark adapted thresholds in rd mice rose with age. This is consistent with morphological changes known to occur in the retina as a consequence, of the rd mutation the rods degenerating before the cones.

Birds as Predators on the Brood of Polybia Wasps (Hymenoptera: Vespidae: Polistinae) in a Costa Rican Deciduous Forest

Birds as Predators on the Brood of Polybia Wasps (Hymenoptera: Vespidae: Polistinae) in a Costa Rican Deciduous Forest

Problems Connected with Plasma Renin Activity Measurements by Angiotensin I Radioimmunoassay

The main application of the radioimmunoassay for angiotensin I is the measurement of plasma renin activity (PRA). Methods published for the measurement of PRA differ in many details and make the comparison of results difficult. This paper deals with some of the problems. 1. The radioactive labelling of angiotensin I using chloramine-T requires the purification of the labelled peptide. A method applying both anion exchange chromatography and gel filtration is described. It resulted in tracer angiotensins of very reproducible characteristics. 2. For the measurement of PRA, the pH of the plasma has to be adjusted prior to the incubation. The adjustment to the physiologic pH of 7.4 is recommended. 0.1 volume of a concentrated buffer controlled the pH during a three hours incubation without diluting the plasma too much. 3. At pH 7.4, EDTA, dimercaprol, and 8-hydroxyquinoline were found to inhibit converting enzyme and angiotensinases better than EDTA and DFP and should therefore be used as inhibiting agents. 4. Nonspecific cross reaction of antisera are the cause of the blank values when angiotensin I is measured in unextracted plasma. The problem of subtraction of a blank may be minimized by the selection of an antiserum of high specificity which shows no or only little nonspecific cross reaction. Lor or unmeasurable blank values will result.

Induction of cystathionase in human foetal liver.

Incubation of liver explants from second-trimester human foetuses with dexamethasone, glucagon or dibutyryl cyclic AMP (plus theophylline) increased the activity of liver cystathionase from unmeasurable or trace values to adult values. Simultaneous incubation with cycloheximide or actinomycin D inhibited this effect.

Dry, vertical wick chromatography for determination of serum growth hormone.

ABSTRACT A modification of the chromatographic method for determination of growth hormone using vertical »dry« chromatography with Whatman 3 MC paper is described. This inexpensive and rapid technique gives a better separation of free from antibody-bound growth hormone than previously published chromatographic techniques. It also gives good reproducibility, with an average recovery percentage of 104. There are high values in acromegalics and unmeasurable values in hypophysectomized patients. The values obtained are independent of antibody concentration.

Practical radiation protection.

The possibility of harmful genetic effects from radiation is discussed. The view is expressed that the contribution to gonad exposure from superficial radiotherapy has probably been overstated. The prudence of taking every precaution to reduce dosage is underlined. The dose measured at the approximate gonad area in the treatment of a series of dermatological patients is listed. Simple and easily applied methods by which this dose can be reduced to low or unmeasurable values are set out. The most important of these are the covering of the table with lead, the use of lead aprons, and the posturing of the patient. The application of these measures by physicians carrying out diagnostic procedures, with accruing protection to their patients and themselves, is pointed out. Mention is made of the value of the routine use of a dosemeter. (auth)

The effect of muscular exercise and hypoglycemia on the plasma level of 17-hydroxysteroids in normal adults and in patients with the adrenogenital syndrome.

In previous experiments performed in collaboration with Miss M. Spengler (Labhart & Spengler, 1953, Spengler, 1953) we have found that following an infusion of 1 mg. of adrenaline the level of the 17′21-dihydroxysteroids in the plasma decreases. Similar experiments have been done by Raile et al. (1952) with no clear result, whereas Sandberg et al. (1953) and Nelson (1953) described a fall in plasma 17′21-dihydroxysteroids after adrenaline infusions or injections in several of their experiments. However, this decrease was not regarded as significant by the authors although the plasma concentration fell to unmeasurable values in some of the experiments. Since it has been shown that compound F represents the bulk of these steroids measured in the blood according to the method of Nelson & Samuels (1952) we thought it possible that adrenaline might increase the utilization of hydrocortisone by the peripheral tissues.

Flow of Liquid Helium II

A SURVEY of the various properties of liquid helium II has prompted us to investigate its viscosity more carefully. One of us1 had previously deduced an upper limit of 10−5 C.G.S. units for the viscosity of helium II by measuring the damping of an oscillating cylinder. We had reached the same conclusion as Kapitza in the letter above ; namely, that due to the high Reynolds number involved, the measurements probably represent non-laminar flow. Evidence for the existence of an unusual liquid phase of 4He below about 2.2 K — the 'λ-point' — can be traced back to 1911 and the experiments of Kamerlingh Onnes. But it was another two decades before a clear picture started to emerge concerning the 'superfluid' nature of this phase. Key to establishing the concept of superfluidity were the measurements of Kapitza and Allen and Misener in 1938, which showed that the viscosity of 4He dropped to essentially unmeasurable values when cooled below the λ-point. [Obituary of Jack Allen: Nature 411, 436 (2001)]