Sequential Conditions Research Articles

Development of a Reliability Test Profile for an ECM Pod Based on Measured Flight Conditions

A test profile was developed to evaluate the reliability of an electronic countermeasures (ECM) pod. The profile combines air and liquid temperature cycling and various vibroacoustic levels to duplicate measured inflight thermal and vibratory response of the ALQ-184 ECM pod. An ALQ-184 ECM pod was equipped with an environmental data collection system that included 25 thermal sensors, 18 vibration sensors, and a telemetry system to allow real-time monitoring of response levels during captive flight. The pod was flown on F-4, F-16, and A-10 aircraft at Eglin Air Force Base (AFB) under typical operation mission conditions. Thermal and vibration response date were analyzed, and a reliability test profile was developed that simulates operational mission conditions for the F-4, F-16, and A-10 aircraft. The test profile is expressed in terms of pod response and is based on using temperature-conditioned air to provide the thermal response of printed wiring assemblies, temperature-conditioned liquid to provide the thermal response for coldplates, and 16 different vibroacoustic levels to provide the pod vibratory response. Each vibroacoustic level used the spectral data from five critical accelerometer locations on the pod structure to defin the required pod response. The 6 hr reliability test profile simulates the thermal and vibratory response for 29 sequential flight conditions for the three aircraft. During the profile, the pod electrical status is cycled between standby, transmit, and off modes. The reliability test profile was used to perform reliability growth testing on early production pods and is being used for reliability qualification and production reliability acceptance testing during production.

Simultaneous Form Perception and Serial Letter Recognition in a Case of Letter-by-letter Reading

Abstract This paper examines the performance of a letter-by-letter reader, PD, on tests which involve the perception of words and letter-strings under tachistoscopic presentation conditions. Unlike the patients recently reported by Bub, Black, and Howell (1989) and Reuter-Lorenz and Brunn (1990), PD shows no evidence of processing the letters of a word in an “ends-in” fashion. Instead, letters appear to be recognised serially from left to right. Furthermore, PD does not show an advantage of words over pseudowords when asked to report the letters from briefly presented letter-strings. In addition, unlike control subjects, he does not show a word superiority effect in same/different judgements about two simultaneously presented letter-strings (Friedrich, Walker, & Posner, 1985). A final experiment reveals that his ability to recognise letters under sequential processing conditions is relatively unimpaired, as is his ability to match letters on the basis of physical features with simultaneous presentation. I...

Ultrastructural Changes in Trichospores of Smittium culisetae and S. culicis during in Vitro Sporangiospore Extrusion and Holdfast Formation

Ultrastructural changes associated with in vitro sporangiospore extrusion (“germination”) and holdfast formation in Smittium culisetae and S. culicis (Trichomycetes) were examined upon treatment of trichospores with potassium at pH 10 (Phase I) followed by a drop in the pH to 7 (Phase II). Phases I and II correspond to sequential conditions encountered by trichospores during passage through the respective midgut and hindgut regions of the insect larval host. In untreated trichospores of S. culisetae, spore bodies were aligned at the apex of the trichospore. Canals in the sporangiospore wall were also present at the apex, along with an interwall layer interposed between the sporangial and sporangiospore walls. No ultrastructural changes were observed at Phase I. Trichospores extruded sporangiospores apically during Phase II and the interwall layer extended outward with the emerging sporangiospore to form the sleeve. Untreated trichospores of S. culicis contained spore bodies scattered throughout the cytoplasm. Canals and an interwall layer were present at both the apex and base of the trichospore. During Phase I, sporangiospores were extruded apically or basally following migration of the spore bodies to either pole of the trichospore. Holdfast formation was restricted to Phase II in both S. culisetae and S. culicis. Disappearance of the spore bodies suggests that they contain the initial holdfast material for attachment to the gut lining. Sporangiospore canals serve as the probable route for expulsion of holdfast material. Holdfasts of S. culisetae adhered to a diversity of substrates in vitro.

Kinetics of acetate, propionate and butyrate removal in the treatment of a semi‐synthetic landfill leachate on anaerobic filter

The kinetics of acetate, propionate, and butyrate removal was studied in conditions of leachate treatment in a plug flow anaerobic fixed-film reactor made of a sequence of seven perfectly mixed compartments. An original experimental procedure was followed under sequential feeding conditions so as to maintain the Bacteriol biomass in a quasi-steady state all along the study. With an appropriate computer program based on the least squares method, the apparent kinetic parameters of VFA removal were calculated within concentration ranges below the levels of salt inhibition. The models proposed are based on simple theoretical considerations. For acetate and n-butyrate removal, the best fits were given by the Michaelis-Menten equation with respectively: V(m) (spec) = 0.49 +/- 0.06 g CH(3) COOH g(-1) biomass h(-1)and 0.18 +/- 0.02 g n-CH(3)CH(2)CH(2)COOH g(-1) biomass h(-1) and: K(s) = 21.2 +/- 0.9 g CH(3)COOH L(-1) liquid phase and 8.2 +/- 0.9 g n-CH(3)CH(2)CH(2)COOH L(-1) liquid phase, Iso-butyrate was produced during n-butyrate catabolism and the apparent removal rate of (n + iso)-butyrate considered as a whole was also described by the Michaelis-Menten equation with V(m) (spec) = 0.14 +/- 0.02 g(n + iso)-butyrate g(-1) biomass h(-1) and K(s) = 9.0 +/- 1.2 g (n + iso) butyrate L(-1) liquid phase. On the other hand in the case of propionate, the best fit was obtained with a first-order equation with K(spec) = (0.88 +/- 0.05) 10(-2) L liquid phase g(-1) biomass h(-1). These constants were subsequently used to predict the removal of mixtures of the three major VFAs under study, at various feed concentrations. Three sets of concentrations were tested, and the experimental data were compared to the simulations. This study, together with other experimental observations previously reported, tends to show that under sequential feeding conditions the classical assumption of butyrate beta-oxidation should be rejected. Butyrate seems to be anaerobically decarboxylated, but propionate thus formed inside the biofilm is degraded as soon as its formation proceeds. It was therefore considered that butyrate degradation produces, through propionate intermediate, 1 mole acetate per mole butyrate removed. When propionate or butyrate concentrations were high, the same phenomenon was noted, to a much lower extent, for the degradation of acetate formed inside the biofilm.

Sequential Conditions and Free Products of Topological Groups

If $A$ and $B$ are nontrivial topological groups, not both discrete, such that their free product $A\coprod B$ is a sequential space, then it is sequential of order ${\omega _1}$.

N-butyrate catabolism in the treatment of a semi-synthetic landfill leachate on anaerobic filter under sequential feeding conditions

Calculations of the kinetics of volatile fatty acids removal in an anaerobic filter showed that methane production from n-butyrate was not consistent with β-oxidation when the reactor was operated under sequential feeding conditions. Under these conditions, n-butyrate might be anaerobically catabolised by decarboxylation. Iso-butyrate was formed at about 25% of the total amount of n-butyrate removed. After 13 days of continuous feeding, the material balance was consistent with the β-oxidation mechanism and the formation of iso-butyrate became negligible. N-butyrate decarboxylation may therefore be a transient catabolic pathway, although the reason why decarboxylation is preferred to β-oxidation under conditions such as sequential feeding is not clear. Results of similar experiments on acetate removal were consistent with theoretical expectations under conditions of both sequential and continous feeding.

Sequential conditions and free products of topological groups

If A A and B B are nontrivial topological groups, not both discrete, such that their free product A ∐ B A\coprod B is a sequential space, then it is sequential of order ω 1 {\omega _1} .

Construction of an ion-exchange amino acid analyser kit for use with high-performance liquid chromatography apparatus

A conventional ion-exchange amino acid analyser kit has been simply and economically constructed for use with existing high-performance liquid chromatography (HPLC) apparatus. Sequential elution conditions are fully programmable by virtue of a 32K BBC microcomputer interfaced with an elution buffer selection valve and a thermostatically controlled column. Post-column derivatization with o-phthalaldehyde—2-mercaptoethanol reagent enables fluorimetric detection at the picomole level. The system enables sensitive amino acid analysis of complex mixtures to be carried out by clinical and research laboratories who already possess HPLC apparatus but whose sample turnover does not merit purchase of a dedicated fully automated analyser.

LV filling pressure during PEEP measured by nadir wedge pressure after airway disconnection.

Pulmonary arterial occlusion pressure (Ppao) may not accurately reflect left ventricular filling pressure (LVFP) during ventilation with positive end-expiratory pressure (PEEP) because increases in pleural pressure (Ppl) increase measured intrathoracic vascular and cardiac chamber pressures relative to atmospheric while decreasing LVFP by decreasing venous return. Steady-state values of Ppao off PEEP are not useful in understanding the hemodynamics on PEEP because of changes in blood volume distribution and ventricular afterload associated with the removal of PEEP. We hypothesized that changes in Ppao immediately after abrupt airway disconnection from PEEP selectively reflect removal of PEEP-associated Ppl changes prior to other physiological changes. In pentobarbital-anesthetized closed-chest dogs, we compared absolute left atrial pressure and left atrial pressure relative to Ppl (Platm) prior to abrupt disconnection from 15 cmH2O PEEP (on-PEEP), with Ppao at its nadir (nadir Ppao) following airway disconnection in three sequential conditions: control (normal), after propranolol-induced acute ventricular failure, and after oleic acid-induced lung injury. For all conditions at low LVFP (less than 9 Torr), nadir Ppao reflects Platm better than on-PEEP Ppao, while at higher LVFP (greater than 9 Torr), on-PEEP Ppao better reflects Platm than nadir Ppao (P less than 0.05). Accurate predictions of on-PEEP Platm can be made using both on-PEEP and nadir Ppao values in a multiple regression equation.

Linear-response function of the quantum Bose fluid. Application to the charged-boson gas

The static-linear-response function $\ensuremath{\chi}(k)$ is derived for the quantum Bose fluid with the use of the hypernetted-chain approximation in the Jastrow theory. The pair-correlation function of the uniform system required as an input function is optimized within the same theory. The compressibility sum rule as well as the sequential and screening conditions are exactly fulfilled by construction. It is shown analytically that in the small-wavelength limit the leading correction in ${\ensuremath{\chi}}^{\ensuremath{-}1}(k)$ to the freeparticle kinetic energy is a constant $\frac{2}{3}\frac{{T}_{\mathrm{JF}}}{N}$, where ${T}_{\mathrm{JF}}$ is the Jackson-Feenberg kinetic energy. We have also developed a reliable numerical method which is used in the calculation of the linear-response function of the charged-boson gas at metallic densities.

The effects of neonatal androgenization of female hamsters on adult preference for female hamster vaginal discharge

The effects of neonatal exposure of hamsters to androgen on the development of an adult preference for female hamster vaginal discharge (FHVD) were investigated. Three groups treated on Days 2–3 postpartum (females administered testosterone propionate (TP) in a peanut oil base, females administered oil alone, and males administered oil alone) were combined factorially with four sequential adult conditions (intact, post-gonadectomy, post-gonadectomy plus TP therapy, and post-gonadectomy) to produce twelve experimental conditions. Statistical analysis indicated that neonatal oil females did not show a significant FHVD preference in any adult condition. Neonatal TP females displayed a significant FHVD preference only in the post-gonadectomy plus TP condition. Males retained a significant FHVD preference in all the adult conditions, although the preference shown in the two adult hormonal conditions (intact and post-gonadectomy plus TP) was significantly higher than the preference shown in the two nonhormonal conditions.

FREQUENCY DISTRIBUTION OF ESTERASE-5 ALLELES IN TWO POPULATIONS OF DROSOPHILA PSEUDOOBSCURA

Statistical tests comparing allele frequencies in natural populations with those predicted by various theories of genic variation depend critically on the accurate enumeration of alleles. This study used a series of five sequential electrophoretic conditions to characterize the allele frequency distributions of esterase-5 in two large population samples of Drosophila pseudoobscura from California. In Standard chromosome lines 12 electromorphs were discriminated using a single electrophoretic condition. When four additional criteria were used, the number of electromorphs increased to 41, 33 in one population and 22 in the other. Both populations had the same two alleles in high frequency, with other alleles present in frequencies of 6% or less. Although each population had a number of unique alleles, a chi(2) contingency test demonstrated no significant genetic divergence between them. A statistical comparison of allele frequencies in both populations with that predicted by neutral models suggests that the individual and combined distributions deviate from neutrality in the direction of purifying selection.-Sex-Ratio chromosomes differed markedly from Standard chromosomes in both allelic content and diversity. In 32 Sex-Ratio chromosomes from one population only three alleles were found, all of which were detected under the initial "standard" electrophoretic conditions. Moreover, none of these alleles was found in the Standard chromosome lines.

Masking and the identification of characters presented simultaneously and sequentially to the parafovea.

The effects of masking and simultaneous vs sequential exposure on identification accuracy of parafoveally presented pairs of stimuli were examined in four experiments. When masking figures were continuously present in positions not occupied by stimulus characters, accuracy of identification was significantly poorer on the relatively central member of a pair when members were simultaneously exposed and when the central member was exposed second. When masking figures were not used, performance was significantly poorer on the central member only when pair members were exposed simultaneously. Requiring the identification of both members of the pair produced a different ordering of overall accuracy among the simultaneous and sequential conditions from when only one member was identified. It was concluded that asymmetric lateral inhibition of feature extraction operated only when target and nontarget were simultaneously present. An additional source of asymmetric disruption occurs when masking figures flanking the target change before or with the appearance of the target.

Enhanced biodegradation of methoxychlor in soil under sequential environmental conditions.

Ring-U-[14C]methoxychlor [1,1-bis(p-methoxyphenyl)-2,2,2-trichloroethane] was incubated in soil under aerobic and anaerobic conditions. Primary degradation of methoxychlor occurred under anaerobic conditions, but not under aerobic conditions, after 3 months of incubation. Analysis of soil extracts, using gas chromatography, demonstrated that only 10% of the compound remained at initial concentrations of 10 and 100 ppm (wt/wt) of methoxychlor. Evidence is presented that a dechlorination reaction was responsible for primary degradation of methoxychlor. Analysis of soils treated with 100 ppm of methoxychlor in the presence of 2% HgCl2 showed that 100% of the compound remained after 3 months, indicating that degradation in the unpoisoned flasks was biologically mediated. Methanogenic organisms, however, are probably not involved, as strong inhibition of methane production was observed in all soils treated with methoxychlor. During the 3-month incubation period, little or no evaluation of 14CO2 or 14CH4 occurred under either aerobic or anaerobic conditions. Cometabolic processes may be responsible for the extensive molecular changes which occurred with methoxychlor because the rate of its disappearance from soil was observed to level off after exhaustion of soil organic matter. After this incubation period, soils previously incubated under anaerobic conditions were converted to aerobic conditions. The rates of 14CO2 evolution from soils exposed to anaerobic and aerobic sequences of environments ranged from 10- to 70-fold greater than that observed for soils exposed solely to an aerobic environment.

On the symmetric algebra of an ideal

The symmetric algebra of an ideal I may be compared to the Rees algebra via the canonical epimorphism α:Sym(I)→R(I). A necessary and sufficient criterion is given for a to be an isomorphism, and sequential conditions on the symmetric algebra are studied. Some applications are given to Proj α:ProjR(I)→Pro'j Sym(I) and to the theory of approximation complexes.

Generalized Reciprocal Imitation following Different Sequential Conditions of Being Imitated and Not Being Imitated

Summary The purpose of the present study was to assess the differential effects of adult imitations of children's responses on children's subsequent imitations of the adult when imitation was preceded by the same condition or by different conditions in which the adult (a) had not imitated the children's responses (nonimitation condition) or (b) had modeled a set of responses (modeling-only condition). The study was also to determine the differential effects of using the same or different adults during each of both subsequent conditions. Forty-two Dutch preschool children were divided into three groups, each exposed to one of three experimental (imitation, nonimitation, or modeling) conditions. Following the induction trials, children were given opportunity to imitate the man who had and another man who had not acted during the induction trials. Following an interval of 10 days, all children received the imitation condition. For half the children in each group the same men were used as in the initial condi...

Sequential Conditions and Free Topological Groups

Sequential Conditions and Free Topological Groups

Sequential conditions and free topological groups

Most of the results in this paper concern relationships between sequential properties of a pointed topological space (X, p) and sequential properties of the Graev free topological group on X. In particular, it is shown that the free group over a sequential k ω {k_\omega } -space is sequential, and that a nondiscrete sequential free group has sequential order equal to ω 1 {\omega _1} (the first uncountable ordinal). The free topological group on a space X which includes a convergent sequence contains a closed subspace homeomorphic to S ω {S_\omega } , a previously studied homogeneous, zero-dimensional sequential space. Finally, it is shown that there is no topological group homeomorphic to S ω {S_\omega } .

Meniere's Disease and Plasma Norepinephrine

Blood pressure and plasma norepinephrine (P-NE) which was evaluated using GC-MS were measured in 9 healthy subjects and 17 patients with Meniere's disease. These values were compared in three different sequential conditions; i) supine position ii) erect position 5 min. after standing iii) erect position 10 min. after standing. P-NE value at supine position of patients with Meniere's disease was slightly lower than that of healthy subjects, though no significant difference was found between two groups.P-NE significantly increased at the erect position 5 min. after standing in both groups, however, this increment was larger in Meniere's disease than in control group.Mean blood pressure increased at this period in both groups, however, this increment was significantly lower in Meniere's disease than in control group.There was no such changes of P-NE and blood pressure at 10 min. after standing in both group.It may be suggested that the patients with Meniere's disease have a relative hyporesponsiveness of blood pressure to endogenously released catecholamine.

Ear dominance and sequential interactions.

When two tones of different frequency are simultaneously presented, one to each ear, a single pitch may be heard that corresponds to the frequency delivered to one ear rather than to the other. That is, the frequency information delivered to one ear may be followed and to the other ear suppressed. The present study explored the sequential conditions under which this effect occurs. Clear ear dominance was obtained in sequences where the two ears received the same frequency in succession. However, ear dominance was absent in sequences where successive dichotic chords were composed of different frequencies. From these and other findings a basis for ear dominance is proposed.