Nonrandom Order Research Articles

A numerical procedure for curve fitting of noisy infrared spectra

A method for the detection of overfitting of noisy spectra is presented. When fitting data that contains random noise, the autocorrelation function ( R L ) of residuals at lag 1 ( R 1) approaches zero and then shows a tendency toward more negative values, while the Wald–Wolfowitz test tends to give more positive values, as the data is overfitted. Models that give residuals with a non-random ordering may be rejected. The use of these functions for the determination of the “best” fitting of several approximations (Savitzky–Golay smoothing, segmented osculating polynomials (SOPA), Fourier series, and Lorentzian bands) to a noisy synthetic spectrum, and the application to infrared spectra of coal, is shown.

Examination of the Structure of the Glutenin Macropolymer in Wheat Flour and Doughs by Stepwise Reduction

The structure of the disulfide-bonded glutenin macropolymer (GMP) in flour and dough was studied by analyzing the depolymerization behavior during stepwise chemical reduction. During reduction, the size distribution of GMP changed, due to the release of subunits, dimers, and oligomers as well as small glutenin aggregates. Glutenin subunits were released from the polymer in a nonrandom order, which was indicative of the polymer having a hierarchical structural organization. Typically, the B-mobility low molecular weight glutenin subunits (LMW-GS) were released at lower reductant concentration than C-mobility LMW-GS and high molecular weight glutenin subunits (HMW-GS), although the B-subunits were released in a partially reduced state. Dimers comprised of either LMW- or HMW-GS were released at low reductant concentrations, but LMW- and HMW-GS were not found together in the same dimers. Some HMW-GS were particularly resistant to reductive dissociation, consistent with them forming a backbone to the glutenin ...

Ultraviolet plumage colors predict mate preferences in starlings.

Avian plumage has long been used to test theories of sexual selection, with humans assessing the colors. However, many birds see in the ultraviolet (<400 nm), to which humans are blind. Consequently, it is important to know whether natural variation in UV reflectance from plumage functions in sexual signaling. We show that female starlings rank males differently when UV wavelengths are present or absent. Principal component analysis of approximately 1300 reflectance spectra (300-700 nm) taken from sexually dimorphic plumage regions of males predicted preference under the UV+ treatment. Under UV- conditions, females ranked males in a different and nonrandom order, but plumage reflectance in the human visible spectrum did not predict choice. Natural variation in UV reflectance is thus important in avian mate assessment, and the prevailing light environment can have profound effects on observed mating preferences.

Organization of Agonistic Vocalizations in Black-Chinned Hummingbirds

We describe vocalizations of Black-chinned Hummingbirds (Archilochus alexandri) recorded during agonistic encounters at feeders. Calls are composed of one to five different note-types that comprise a recombinatorial system exhibiting syntax. A Markov analysis revealed non-random ordering of note-types. The distribution of call-types (unique combinations of notes) illustrates openness; the number of call-types increases as more calls are sampled. Constraints on call length occur that are related to the length of individual note-types; shorter note-types are more common in calls with more notes. No sex differences occurred in the call-types with the exception of the Z note which occurred more often in male calls. The agonistic vocalizations of these hummingbirds demonstrate a level of vocal complexity comparable to songs of many passerines. We compare the vocalizations of the Black-chinned Hummingbird with studies of Anna’s Hummingbird (Calypte anna) and point out major differences in repertoire organization. Marked similarities occur between organization of calls in certain chickadees (Parus) and that of the Black-chinned Hummingbird. This finding is surprising in view of their phyletic differences, but may reflect certain underlying constraints on the organization of avian vocalizations.

96/03409 - Power optimization of an endoreversible regenerative Brayton cycle

A method for the detection of overfitting of noisy spectra is presented. When fitting data that contains random noise, the autocorrelation function (RL) of residuals at lag 1 (R1) approaches zero and then shows a tendency toward more negative values, while the Wald–Wolfowitz test tends to give more positive values, as the data is overfitted. Models that give residuals with a non-random ordering may be rejected. The use of these functions for the determination of the “best” fitting of several approximations (Savitzky–Golay smoothing, segmented osculating polynomials (SOPA), Fourier series, and Lorentzian bands) to a noisy synthetic spectrum, and the application to infrared spectra of coal, is shown.

Idazoxan and Response to Typical Neuroleptics in Treatment-Resistant Schizophrenia

We investigated whether antagonism of alpha 2 adrenergic receptors would augment treatment response in schizophrenia, by administering idazoxan, an alpha 2 antagonist drug, to treatment-resistant patients on typical neuroleptics. Seventeen hospitalised treatment-resistant patients with DSM-III-R schizophrenia or schizoaffective disorder were studied on typical neuroleptic treatment, on treatment with idazoxan plus typical neuroleptic, and after discontinuation of idazoxan, in fixed, non-random order, and under double-blind, placebo-controlled conditions. The addition of idazoxan to fluphenazine treatment resulted in significant reductions of global psychosis and total, positive and negative symptoms on the Brief Psychiatric Rating Scale, compared to neuroleptic treatment alone. Symptom improvement significantly correlated with idazoxan-induced changes in indices of noradrenergic function. In a subgroup of patients, idazoxan plus typical neuroleptic treatment compared favourably with clozapine treatment, when both were compared to typical neuroleptic treatment alone. The antagonism of alpha 2 receptors augmented therapeutic response to typical neuroleptic treatment in treatment-resistant patients with schizophrenia. This antagonism may contribute to clozapine's superior antipsychotic effects.

Growth cone behavior underlying the development of stereotypic synaptic connections in Drosophila embryos

Each muscle fiber in the segmented body wall of Drosophila larvae is innervated by anatomically stereotyped neuromuscular junctions. These synapses arise through the selective choices of motoneuronal growth cones at their peripheral targets. Using digital optical microscopy of staged intracellular dye fills, we have singly identified embryonic motoneurons and have examined individual growth cones when they contact and differentiate at the target cells. There is a precise connectivity between motoneuron and muscle fiber, which is the direct consequence of growth cone behavior. We have also found that Drosophila muscle fibers possess molecularly heterogeneous cell surfaces that may be involved in growth cone recognition of appropriate targets. Fasciclin III, a homophilic adhesion molecule, is coexpressed by several of the efferent growth cones and in a site-specific fashion by the target muscle fiber's membrane. The fasciclin III expression is transient, corresponding to the period in embryogenesis when the first neuromuscular contacts are made. Upon encountering the target cell surface, the growth cones can sprout stereotypically arrayed filopodial processes, orient along the anterior-posterior axis, and turn in predictable directions. Subsequently, terminal branches are established in a nonrandom order. These phenomena were found to occur in two motoneurons that innervate adjacent muscle fiber targets, and may be general features of neuromuscular synaptogenesis in Drosophila.

RANDOMISATION AND THE 1975 SENATE BALLOT DRAW

Summary “So the last shall be first, and the first last; for many be called, but few chosen.” Matthew 20:16 The “random” draw for positions on the Senate ballot papers in the 1975 election resulted in an apparently non-random ordering, to the possible advantage of one particular party. This paper assesses the statistical significance of the 1975 draw and looks at possible causes of the evident non-randomness. A simplified yet realistic mathematical model is used to describe conditions under which the so-called donkey vote can have an effect on the final outcome of the election, thereby confirming the widely-held belief that the order of parties on the Senate ballot paper is relevant. We examine other Senate elections between 1949 and 1983 for the existence of relevant non-randomness similar to the 1975 result. Finally, we report briefly on our submission to the 1983 Joint Select Committee on Electoral Reform, which led to an improvement in the randomisation procedure.

Anderson localization problems in gapless superconducting phases

The interplay of Anderson localization and different kinds of superconducting order is most interesting in “gapless” cases, i.e. for nonvanishing electron density of states at EF. I present a new renormalization group result for Anderson localization in the gapless type II limit of an Ising superconducting (SC) glass. From this calculation a guess is also made for the XY superconducting glass. In both cases, and in contrast to localization in normal systems, two renormalization constants (one for field- and one for coupling constant renormalization) are necessary (and sufficient). The density of states at EF is singular with exponent β. For the Ising SC-glass I obtain vI = 1/(d − 2), βI = 1/2, and ηI = 0, while the XY SC-glass has vXY = 1/(d − 2), βXY = 1, and ηXY = d − 2, all in leading order of the d − 2 expansion and for E = EF. For E≠EF a symmetry argument, and also the calculation given here, predict usual localization behaviour with v = 1/(d − 2), β = 0, and η = 2 − d in both cases.The effects of Cooper pairs on localization in the pure superconducting glasses is compared with earlier results showing perfect coexistence of Anderson localization with dirty superconductivity approximately described by a nonrandom order parameter. These limiting cases are embedded in a more general field theory given here, which contains three superconducting order parameters and a conventional pair-breaking mechanism.

Modal gating behavior of cardiac sodium channels in cell-free membrane patches

Single voltage-activated Na+ channel currents were obtained from membrane patches of isolated ventricular cells of guinea pig hearts. The currents were compared when measured from cell-attached patches and from the same patch but at least 20 minutes after manual excision. The averaged currents showed a distinctly delayed decay in the excised patches due to the appearance of long lasting openings or bursts of openings. In contrast to control patches, the open time distribution in excised patches requires at least two exponentials. A short mean open time was voltage independent for cell-attached patches (0.38 ms +/- 0.07 ms between -60 and -20 mV, 6 cell-attached patches; and 0.41 +/- 0.1 ms, 7 excised patches). The long mean open time found in excised patches was clearly voltage dependent and increased from 0.48 +/- 0.14 ms (-80 mV) to 2.87 +/- 0.35 ms (-20 mV, regression coefficient +0.88, 7 patches). Sweeps with long openings appeared in clusters. The clustering of records with long openings, short openings, or without openings (nulls) was quantified by a runs analysis which showed a highly significant nonrandom ordering. The results show that in excised patches inactivation is temporally hibernating.

Reactions to fear as a proximate factor in the sociospatial organization of baboon progressions.

The objective of this study was to test the hypothesis that fearfulness is a key proximate factor determining the nonrandom order repeatedly reported for baboon troops progressing from one location to another. According to this hypothesis, the most vulnerable troop members, the walking immatures, are expected in most circumstances to be cautious and to keep others between themselves and potential danger. The more confident adults, especially large powerful males, should tend toward the front and rear of progressing troops. The fear hypothesis predicts that in progressions toward a fear source, adult males should be near the front of the troop; on the other hand, when the troop is retreating from a frightening or tense situation, adult males should be found more toward the rear. Progressions of chacma baboons away from the location of a severe fright or in retreat from another troop were compared with other progressions. Adult males tended to be more rearward in these situations. The number of adults of either sex interposed between a fear source and the first walking immature was greater for retreating troops than for others. Some adult males continued to be near the front of the troop when retreating from tense situations.

Statistical analysis of single sodium channels. Effects of N-bromoacetamide

Currents were obtained from single sodium channels in outside-out excised patches of membrane from the cell line GH3. The currents were examined in control patches and in patches treated with N- bromoacetamide ( NBA ) to remove inactivation. The single-channel current-voltage relationship was linear over the range -60 to + 10 mV, and was unaffected by NBA . The slope conductance at 9.3 degrees C was 12 pS, and the Q10 for single channel currents was about 1.35. The currents in both control and NBA -treated patches showed evidence of a slow process similar to desensitization in acetylcholine-receptor channels. This process was especially apparent at rapid rates of stimulation (5 Hz), where openings occurred in clusters of records. The clustering of records with and without openings was analyzed by runs analysis, which showed a statistically significant trend toward nonrandom ordering in the responses of channels to voltage pulses. NBA made this nonrandom pattern more apparent. The probability that an individual channel was "hibernating" during an activating depolarization was estimated by a maximum likelihood method. The lifetime of the open state was also estimated by a maximum likelihood method, and was examined as a function of voltage. In control patches the open time was mildly voltage-dependent, showing a maximum at about -50 mV. In NBA -treated patches the open time was greater than in the control case and increased monotonically with depolarization; it asymptotically approached that of the control patches at hyperpolarized potentials. By comparing channel open times in control and NBA -treated patches, we determined beta A and beta I, the rate constants for closing activation gates and fast inactivation gates. Beta I was an exponential function of voltage, increasing e-fold for 34 mV. beta A had the opposite voltage dependence. The probability of an open channel closing its fast inactivation gate, rather than its activation gate, increased linearly with depolarization from -60 to -10 mV. These results indicate that inactivation is inherently voltage dependent.

Tissue-specific elimination of alternative whole parental genomes in one barley hybrid

Chromosome elimination was studied in squash preparations of seeds of two different Hordeum crosses between diploid parents whose karyotypes allowed identification with unusual ease for Hordeum of the parental origins of the chromosomes being eliminated in each mitosis in embryos and endosperms. In both crosses, the mean chromosome number in hybrid tissues fell during several mitoses until nuclei became haploid in embryos and diploid in endosperms. Elimination was always uniparental, i.e. all chromosomes eliminated from a given tissue in a given cross were from the same parent. In H. marinum x H. vulgare cv. Tuleen 346, elimination involved the Tuleen 346 genome in the endosperm, but the H. marinum genome in the embryo. This is a good example of alternative elimination, i.e. uniparental elimination involving different parental genomes in different tissue of the same cross. In Tuleen 346 x H. bulbosum, the H. bulbosum genome was eliminated from both embryos and endosperms. — In H. marinum x Tuleen 346 endosperms, eliminated Tuleen 346 chromosomes were individually identifiable and tended to be eliminated in non-random order: the nucleolar chromosomes, T3-7 and T6-2 first, followed by chromosomes T5-1, T7-3, T2-6 and 4, with chromosome T1-5 last. — The nucleolar constrictions were expressed in eliminated satellite chromosomes from Tuleen 346, but not in those from H. marinum or H. bulbosum. Eliminated chromosomes differed from retained ones in having smaller centromeres and tending before, during and after elimination to occupy more peripheral regions of mitoses. Elimination may result primarily from specific suppression of genes involved in centromere function, perhaps by DNA methylation.

Immunoglobulin heavy-chain switching in pre-B leukaemias.

Immunoglobulin gene expression is initiated in pre-B cells by rearrangements of heavy-chain variable genes V, D and J, for transcription together with the constant region gene C mu (refs 1-7). The subsequent joining of light-chain V-J genes in the kappa or lambda families leads to formation of complete IgM molecules, which are then expressed on the surface of B cells. Heavy-chain isotype switching has been thought to occur later and to involve CH gene rearrangement via deletion of DNA between a switch site 5' to C mu and a switch site 5' to the downstream C gamma, C epsilon or C alpha gene expressed by a mature plasma cell. On the other hand, isotype switching has been seen in human pre-B-cell leukaemias and in a murine pre-B-cell line before light-chain gene rearrangements and without C mu gene deletion. To explore further the isotype switching in pre-B cells, we used monoclonal antibodies in immunofluorescence assays to allow unambiguous assignment of the heavy-chain isotypes expressed by individual leukaemic cells in 11 pre-B-cell leukaemias. Switching in these leukaemic clones invariably led to expression of gamma 1 heavy-chain and kappa light-chain determinants, occasionally together with gamma 4 and alpha. These results indicate a nonrandom order for heavy-chain isotype switching and for light-chain isotype expression, and also suggest that a mechanism exists for coordinating the two events.

An amplified chromosomal sequence that includes the gene for dihydrofolate reductase initiates replication within specific restriction fragments.

We have developed a methotrexate-resistant Chinese hamster ovary cell line (CHOC 400) containing a 500-fold amplification of a 135-kilobase chromosomal DNA sequence. This sequence includes the gene for dihydrofolate reductase (tetrahydrofolate dehydrogenase, 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3). The high copy number of the amplified sequence permits it to be visualized as a distinct series of restriction fragments in genomic digests separated on ethidium bromide-stained agarose gels. Initiation of DNA replication in the amplified sequence was studied by radiolabeling DNA synthesized during the onset of S phase in synchronized CHOC 400 cells. Autoradiography of Southern blots of labeled genomic digests shows that DNA synthesis initiates in a small subset of the EcoRI fragments derived from the amplified units. These early labeled fragments are not synthesized at later times during S phase, when different subsets of fragments are synthesized. Regardless of the drug used to collect cells at the beginning of S phase, the replication pattern observed remains the same. These data suggest that replication of the amplified sequence initiates at specific sites within each repeated unit and proceeds in nonrandom order throughout the remainder of the sequence--i.e., that initiation of DNA synthesis in the chromosomes of mammalian cells is sequence specific.

Adult male positioning in baboon progressions: order and chaos revisited.

Evidence of nonrandom positioning among adult males is crucial for a protection theory of the spatial organization of baboon progressions. In a recent study it was suggested that systematic positioning of troop members other than mothers and infants is so slight and rare that progressions may be regarded as essentially random. This suggestion depends upon debatable methodological points presumably downgrading previous findings of nonrandom order. Reanalysis of data from this study revealed numerous analytical and statistical problems, as well as serious calculation and other errors, and showed that the findings are consistent with results of the present and previous research. Adult males tended toward the front or back of progressions, a tendency which was intensified in potentially dangerous situations. Dominant males were disproportionately more often frontward and subordinate males rearward. Nonrandom order, which was found for a variety of circumstances at high levels of statistical significance, was unusually general in that it occurred in 6 studies, 7 troops, 2 species, and 5 locations. Such generality is consistent with a protection theory postulating phylogenetic underpinnings of a sociospatial organization which allows an advanced primate to adapt to terrestrial coexistence with predators.

Growth-induced lowering of magnetoelastic symmetry

Growth-induced nonrandom ordering of ions on crystallographically equivalent sites of cubic magnetic garnets may reduce the symmetry of both the anisotropy and magnetoelastic tensors. The crystal tensors can be evaluated as weighted sums over all sites of the local ionic tensors. Such sums reflect both the site symmetries and the site occupation preferences. Unlike the anisotropy (whose growth-induced axial terms are of lower order in the spin components than the cubic terms) the growth-induced magnetoelastic tensor is of the same rank as the cubic component; it may, however, lack the symmetry between strain and spin components imposed by the cubic point group. We determine the symmetry and estimate the magnitude of the non-cubic magnetostriction associated with nonrandom rare earth site occupation, an effect that should be observable. We argue on plausible grounds that the non-cubicity associated with iron ions should be much smaller.

Advances in geophysical exploration of ice sheets and glaciers

AbstractThe techniques of geophysical exploration can be used in a number of ways to investigate the internal characteristics of ice bodies. The application of radio-echo sounding is discussed elsewhere by Robin (1975[a]) so is not considered here except for a few special cases. Anisotropy resulting from non-random ordering of crystal axes produces effects on seismic wave propagation speeds measurable by both refraction and reflection techniques. The effects on shear waves are particularly strong, so the recent development of an effective shear-wave generator should prove very useful. Marked effects on radio-wave polarizations have also been noted, but are not readily interpretable because the anisotropic dielectric characteristics of single-crystal ice in the radio-echo frequency range are not yet known. Elastic internal friction can be determined by careful measurements of seismic-wave amplitudes. Dielectric properties of the ice can be found from VLF propagation experiments and electrical logging in drill holes as well as from the radio-echo sounding techniques discussed by Robin (1975[a]). An activation energy can be estimated from d.c. resistivity measurements where the temperature profile is known. Recent developments have led to much improved methods of determining density-depth variations and long-term mean annual snow accumulation rates from seismic refraction shooting. Internal discontinuities which can be studied include a probable morainal layer detected by seismic reflections, a brine-soaked zone in shelf ice observed from radio-echo. sounding and electrical resistivity surveying, and inverted crevasses penetrating upward from the base of shelf ice, detected by radio echoes. Secular changes in gravity offer a sensitive means of determining long-term changes in surface elevation.

Advances in geophysical exploration of ice sheets and glaciers

AbstractThe techniques of geophysical exploration can be used in a number of ways to investigate the internal characteristics of ice bodies. The application of radio-echo sounding is discussed elsewhere by Robin (1975[a]) so is not considered here except for a few special cases. Anisotropy resulting from non-random ordering of crystal axes produces effects on seismic wave propagation speeds measurable by both refraction and reflection techniques. The effects on shear waves are particularly strong, so the recent development of an effective shear-wave generator should prove very useful. Marked effects on radio-wave polarizations have also been noted, but are not readily interpretable because the anisotropic dielectric characteristics of single-crystal ice in the radio-echo frequency range are not yet known. Elastic internal friction can be determined by careful measurements of seismic-wave amplitudes. Dielectric properties of the ice can be found from VLF propagation experiments and electrical logging in drill holes as well as from the radio-echo sounding techniques discussed by Robin (1975[a]). An activation energy can be estimated from d.c. resistivity measurements where the temperature profile is known. Recent developments have led to much improved methods of determining density-depth variations and long-term mean annual snow accumulation rates from seismic refraction shooting. Internal discontinuities which can be studied include a probable morainal layer detected by seismic reflections, a brine-soaked zone in shelf ice observed from radio-echo. sounding and electrical resistivity surveying, and inverted crevasses penetrating upward from the base of shelf ice, detected by radio echoes. Secular changes in gravity offer a sensitive means of determining long-term changes in surface elevation.

Low-Temperature Transitions in Tetramethylammonium Manganese Chloride

We have measured the proton nuclear magnetic resonance of tetramethylammonium manganese chloride, a linear chain antiferromagnet, in the temperature region 0.4-300 K. In addition, its ac magnetic susceptibility was measured in applied fields of 0 to 22 kG in the temperature range 0.3-4.2 K. When measured along the crystallographic $c$ axis, the zero-field susceptibility had an anomaly at 0.84 K. When the external field was applied perpendicularly to the $c$ axis below 0.8 K, a critical field of 11.5 kG was observed in $\frac{\mathrm{dM}}{\mathrm{dB}}$. The proton NMR did not indicate any cooperative transition to a magnetically ordered state of the ${\mathrm{Mn}}^{2+}$ spins. It did indicate, however, a gradual diminution of fluctuations in the crystallographic $\mathrm{ab}$ plane until a nonrandom order had been established between chains below approximately 0.8 K. We find that the tetramethylammonium groups cease all rotations below 39 K. In the region of 40 to 50 K, the tetramethylammonium groups not only undergo some hindered rotations, but their orientation is different from the published room-temperature x-ray diffraction results. Above 50 K only a single narrow NMR line is observed and, consequently, no additional information on the crystal structure could be obtained.