Bimodal Frequency Research Articles

Design and evaluation of noise suppression sheet for GHz band utilizing magneto-elastic effect

Feasibility of realizing a noise suppression sheet (NSS) coping with the low SHF band such as the 5GHz band was investigated, which was composed of soft magnetic metal flakes dispersed in a polymer. For suppressing noises, the higher frequency one of the bimodal frequency dispersion (lower frequency one: Dispersion DII, higher frequency one: Dispersion DIII) seen in the imaginary permeability (μ″; magnetic loss component) spectrum of the NSS was aimed to utilize. Referring to the previous finding that Dispersion DIII is originated from a magneto-elastic effect, several magnetic composite sheets were prepared using various alloy flakes with different saturation magnetostriction (λs), and their frequency (fr(DIII)) and magnitude (μ″(DIII)) of Dispersion DIII were investigated. It was found that the NSS containing flakes with higher λs exhibited higher fr(DIII) and higher μ″(DIII)/μ″(DII), which was ratio of μ″(DIII) to the magnitude of Dispersion DII (μ″(DII)). The fr(DIII) for the NSS having the highest λs containing Fe-Co alloy flake reached 7.45GHz and μ″ in the 5GHz band was approximately twice as high as the conventional NSS containing Fe-Si-Al alloy flake. For transmission attenuation power ratio (Rtp) when an NSS was placed on a microstrip line with characteristic impedance of 50Ω, NSS with larger fr(DIII)2·μ″(DIII)∝Ms2 (Ms: saturation magnetization), which theoretically gave the frequency limit of imaginary permeability for a thin film, exhibited larger Rtp in the low SHF band. These results suggested that an NSS containing a magnetic flake material with both large λs and Ms was suitable for suppressing low SHF band noises.

Synchronous dynamics in the Kuramoto model with biharmonic interaction and bimodal frequency distribution.

In this work, we study the Kuramoto model with biharmonic interaction and bimodal frequency distribution. Rich synchronous dynamics, such as standing wave states, stationary partial synchronous dynamics, and multiplicity of singular synchronous dynamics, are found. Notably, we find a symmetry-breaking synchronous dynamics when the peaks in frequency distribution are not well separated. We present the phase diagrams for two cases: the peaks in the frequency distribution are well separated and the peaks are not well separated. We find that reducing peak distance tends to make the transition between standing wave states and stationary partial synchronous states to be continuous when the multiplicity of singular synchronous state is present or to be discontinuous when the multiplicity is absent.

Adaptive elimination of synchronization in coupled oscillator

We present here an adaptive control scheme with a feedback delay to achieve elimination of synchronization in a large population of coupled and synchronized oscillators. We validate the feasibility of this scheme not only in the coupled Kuramoto’s oscillators with a unimodal or bimodal distribution of natural frequency, but also in two representative models of neuronal networks, namely, the FitzHugh–Nagumo spiking oscillators and the Hindmarsh–Rose bursting oscillators. More significantly, we analytically illustrate the feasibility of the proposed scheme with a feedback delay and reveal how the exact topological form of the bimodal natural frequency distribution influences the scheme performance. We anticipate that our developed scheme will deepen the understanding and refinement of those controllers, e.g. techniques of deep brain stimulation, which have been implemented in remedying some synchronization-induced mental disorders including Parkinson disease and epilepsy.

Turbidite Events Recorded in Deep‐sea Core IR‐GC1 off Western Sumatra: Evidence from Grain‐size Distribution

AbstractSediment core IR‐GC1, from the abyssal basin of the Indian Ocean off Sumatra, may provide important information on depositional events related to earthquakes and tsunamis. In this study, based on a combination of grain‐size analysis with lithological studies and oxygen isotope stratigraphy, seven deep‐sea turbidite layers were identified, corresponding to seven turbidity events that occurred at 128–130, 105–107, 98–100, 86–87, 50–53, 37–41 and 20–29 ka. The sediments of the turbidite deposits are characterized by coarse grain sizes, poor sorting, wide kurtosis, bimodal frequency distributions and clear depositional variations. Particle size grading is also an important signature of deep‐sea turbidite deposits and can be used as an indicator to identify turbidite layers. Possible triggering mechanisms for the turbidite events include tsunamis, earthquakes, volcanic eruptions and sea‐level changes.

Effects of root diameter, branch order, soil depth and season of birth on fine root life span in five temperate tree species

Fine root life span is a key variable influencing the belowground dynamics of forest ecosystems and is known to be associated with a complex suite of endogenous and environmental factors. We investigated how root life span is influenced by root diameter, branch order, season of birth and soil depth of birth for five temperate tree species growing in monoculture plantations at a common site in northeastern China. The minirhizotron approach was used to estimate root life span from April 2008 to October 2009. Cox proportional hazards regression analysis was employed to determine the impact of those four factors on root life span of each species. There was no consistent difference in fine root life span between evergreen conifers and deciduous hardwoods. A bimodal frequency distribution of root life span was observed for all the species; the majority of roots born in summer and autumn survived to the following year, while roots born in spring mostly died in the current growing season. Root life span tended to increase with root diameter across all species, except Juglans mandshurica. The first two root branch orders within each species generally shared similar life span, with the exception of Picea koraiensis. Root life span tended to be longer at greater depths in the soil profile across all five species. Our results suggest that root life span generally depends on complex interrelations among root anatomy, soil environment and seasonal climatic conditions.

Infants Extract Frequency Distributions from Variable Approximate Numerical Information

Previous research shows that infants represent approximate number: After habituation to a constant numerosity (e.g., eight dots), 6‐month‐old infants dishabituate to a novel numerosity (e.g., 16 dots). However, numerical information in the real world is far more variable and rarely offers repeated presentations of a single quantity. Instead, we often encounter quantities in the form of distributions around a central tendency. It remains unknown whether infants can represent frequency distributions from this type of distributed numerical input. Here, we asked whether 6‐month‐old infants can represent distributions of large approximate numerosities. In two experiments, we first familiarized infants to sequences of dot collections with varying numerosities. For half the infants, the sequence contained a unimodal frequency distribution, with numerosities centered around a single mean, and for the other half, it contained a bimodal frequency distribution of numerosities with two numerical peaks. We then tested infants with alternating or constant numerosities. Infants who had been familiarized to a unimodal distribution looked longer at alternating numerosities than constant numerosities (experiments 1 and 2), whereas infants who had been familiarized to a bimodal distribution looked longer at constant numerosities (Exp. 2). These findings suggest that infants can spontaneously extract frequency distributions from distributed numerical input.

Histopathological of lymph node biopsies in Lagos, South West Nigeria

Lymph nodes are discrete ovoid lymphoid structures that are widely distributed throughout the body. Lymph node enlargement is a common clinical problem, and biopsies are usually undertaken to determine the cause of nodal enlargement. The aim of this study is to elucidate the pattern of lymph node biopsies seen in Lagos State University Teaching Hospital (LASUTH), Ikeja. This is an 8 year retrospective study of all lymph node biopsies sent to our laboratory between 1st January 2008 and 31st December 2015. All slides were retrieved and reviewed. The demographic data regarding age, sex, provisional diagnosis and site of biopsy were obtained from request forms. The data were analysed using the Statistical Package for Social Science version 21. There were 123 lymph node biopsies seen during the study period with age range of 1- 78 years and male to female ratio of 1.2:1. The first decade recorded the highest samples (17.9%), followed by the 4th decade (17.1%). The cervical region is the most common site biopsied, (41.5%), followed by axillary lymph node (17.1%). Metastasis was the most common diagnosis (26.0%), then tuberculous lymph nodes (22.8%). Metastasis was commonest in females and in the 5th decade while tuberculosis was most common in males and in the 4th decade. Metastasis is the most common cause of lymph node enlargement and seen predominantly in females in the fifth decade of life. Tuberculosis is commonest in fourth decade while lymphoma showed bimodal frequency in first and sixth decade.Keywords: nodal enlargement, metastasis, tuberculosis, lymphoma

Serpentine, Iron-rich Phyllosilicates and Fayalite Produced by Hydration and Mg Depletion of Peridotite, Duluth Complex, Minnesota, USA

Serpentine formed from Fe-rich igneous forsterite (Fa 38–43 ) in two samples of peridotite from the Layered Series of the Duluth igneous complex, Minnesota, is enriched to at least 30% of the Fe end-member. In addition to lizardite, chrysotile, and clinochlore, electron microprobe and transmission electron microscope study reveals the presence of metamorphic fayalite (Fa 53–80 ) and Fe-rich phyllosilicates such as magnesian hisingerite, low-Al ferrosaponite, and chamosite. These phyllosilicates are physically mixed on a nano-scale (in part interlayered) with the serpentine. Chlorite and serpentine compositions tend to mirror the bimodal frequency of Fa% in olivine, suggesting a measure of local FeMg –1 exchange equilibrium. A trioctahedral, ferrian ferrosaponite is believed to have replaced the hisingerite, and a more Si-rich ferrosaponite has filled pores in chrysotile and locally replaced it. Both varieties of ferrosaponite are attended unevenly by the presence of up to 1 wt % Na 2 O and K 2 O. Mixtures of lizardite with hisingerite show a gradual increase in Ca toward the latter up to 0·08 atoms per formula unit (1·5 wt % CaO). The presence of 10 and 13 wt % MgO in hisingerite indicates at least 25 and 34 mol % solid solution of Mg-serpentine. Both saponite and hisingerite probably contribute to the yellow color of alteration in thin section. The abundance of Fe-rich phyllosilicates (X Fe = 0·5–0·9) and magnetite in the phyllosilicate microveins argues for a loss of Mg from the rock accompanying the hydrous alteration. This mass change accounts for the growth of magnesian fayalite as a unique product of a low-temperature hydration reaction that ordinarily only consumes olivine. The removal of Mg is inferred to have taken place initially at low fO 2 and temperature very roughly 300°C, under the action of an infiltrating acidic, aqueous fluid. This fluid was probably influenced by nearby concentrations of Cu–Ni sulfides, or alternatively it was derived from underlying graphitic, sulfidic metapelites. Mg loss accompanying serpentinization is not exclusively a feature of hydrospheric alteration; it can instead be induced by a hydrothermal fluid of hitherto unrecognized composition. Growth of hisingerite and ferrosaponite (and its partial oxidation) is inferred to have taken place at a late stage under cooler and more oxidizing conditions. Similar MgFe-phyllosilicates and ferroan olivine are found in terrestrial ore deposits, on the ancient (Noachian) cratered surface of Mars, and in Martian meteorites (nakhlites). Other layered ultramafic–mafic intrusions, zoned intrusions, and ophiolites with Cu–Ni sulfide concentrations may conceivably be found locally to show the same style of serpentinization with major Mg depletion.

Short episodes of crust generation during protracted accretionary processes: Evidence from Central Asian Orogenic Belt, NW China

Accretionary orogens are major sites of generation of continental crust but the spatial and temporal distribution of crust generation within individual orogens remains poorly constrained. Paleozoic (∼540–270 Ma) granitic rocks from the Alati, Junggar and Chinese Tianshan segments of the Central Asian Orogenic Belt (CAOB) have markedly bimodal age frequency distributions with peaks of ages at ∼400 Ma and 280 Ma for the Altai segment, and ∼430 Ma and 300 Ma for the Junggar and Chinese Tianshan segments. Most of the magma was generated in short time intervals (∼20–40 Ma), and variations in magma volumes and in Nd–Hf isotope ratios are taken to reflect variable rates of new crust generation within a long-lived convergent plate setting. The Junggar segment is characterized by high and uniform Nd–Hf isotope ratios (εNd(t)=+5 to +8; zircon εHf(t)=+10 to +16) and it appears to have formed in an intra-oceanic arc system. In the Altai and Chinese Tianshan segments, the Nd–Hf isotope ratios (εNd(t)=−7 to +8; zircon εHf(t)=−16 to +16) are lower, although they increase with decreasing age of the rock units. The introduction of a juvenile component into the Chinese Tianshan and Altai granitic rocks appears to have occurred in continental arc settings and it reflects a progressive reduction in the contributions from old continental lower crust and lithospheric mantle. Within the long-lived convergent margin setting (over ∼200 Ma), higher volumes of magma, and greater contributions of juvenile material, were typically emplaced over short time intervals of ∼20–40 Ma. These intervals were associated with higher Nb/La ratios, coupled with lower La/Yb ratios, in both the mafic and granitic rocks, and these episodes of increased magmatism from intraplate-like sources are therefore thought to have been in response to lithospheric extension. The trace element and Nd–Hf isotope data, in combination with estimates of granitic magma volumes, highlight that crust generation rates are strongly non-uniform within long-lived accretionary orogens. The estimated crust generation rates range from ∼0.1 to ∼40 km3/km/Ma for the Paleozoic record of the CAOB, and only comparatively short (20–40 Ma) periods of elevated magmatic activity had rates similar to those for modern intra-oceanic and continental arcs.

SHORT EPISODES OF CRUST GENERATION DURING PROTRACTED ACCRETIONARY PROCESSES: EVIDENCE FROM CENTRAL ASIAN OROGENIC BELT, NW CHINA

Abstract Accretionary orogens are major sites of generation of continental crust but the spatial and temporal distribution of crust generation within individual orogens remains poorly constrained. Paleozoic (∼540–270 Ma) granitic rocks from the Alati, Junggar and Chinese Tianshan segments of the Central Asian Orogenic Belt (CAOB) have markedly bimodal age frequency distributions with peaks of ages at ∼400 Ma and 280 Ma for the Altai segment, and ∼430 Ma and 300 Ma for the Junggar and Chinese Tianshan segments. Most of the magma was generated in short time intervals (∼20–40 Ma), and variations in magma volumes and in Nd–Hf isotope ratios are taken to reflect variable rates of new crust generation within a long-lived convergent plate setting. The Junggar segment is characterized by high and uniform Nd–Hf isotope ratios ( e Nd ( t ) = + 5 to + 8 ; zircon e Hf ( t ) = + 10 to + 16 ) and it appears to have formed in an intra-oceanic arc system. In the Altai and Chinese Tianshan segments, the Nd–Hf isotope ratios ( e Nd ( t ) = − 7 to + 8 ; zircon e Hf ( t ) = − 16 to + 16 ) are lower, although they increase with decreasing age of the rock units. The introduction of a juvenile component into the Chinese Tianshan and Altai granitic rocks appears to have occurred in continental arc settings and it reflects a progressive reduction in the contributions from old continental lower crust and lithospheric mantle. Within the long-lived convergent margin setting (over ∼200 Ma), higher volumes of magma, and greater contributions of juvenile material, were typically emplaced over short time intervals of ∼20–40 Ma. These intervals were associated with higher Nb/La ratios, coupled with lower La/Yb ratios, in both the mafic and granitic rocks, and these episodes of increased magmatism from intraplate-like sources are therefore thought to have been in response to lithospheric extension. The trace element and Nd–Hf isotope data, in combination with estimates of granitic magma volumes, highlight that crust generation rates are strongly non-uniform within long-lived accretionary orogens. The estimated crust generation rates range from ∼0.1 to ∼40 km3/km/Ma for the Paleozoic record of the CAOB, and only comparatively short (20–40 Ma) periods of elevated magmatic activity had rates similar to those for modern intra-oceanic and continental arcs.

Frequency channel-dependent selectivity for temporal call characteristics in gray treefrogs, Hyla versicolor.

Sensory receptors transmit information on multiple stimulus dimensions. Much remains to be understood about how the processing of different signal characteristics is partitioned and integrated in different areas of the nervous system. Amphibian hearing involves two morphologically distinct inner-ear organs that process different components of the frequency spectrum. Many anuran signals contain two frequency peaks, each one matching the sensitivity of one of these two organs. We hypothesized that the processing of temporal characteristics of acoustic signals would differ in these two frequency channels, perhaps because of differences in the response properties of the two inner-ear organs. We tested this hypothesis in the gray treefrog, Hyla versicolor; male advertisement calls of this species contain a bimodal frequency spectrum. We generated synthetic male advertisement calls in which we independently manipulated the pattern of amplitude modulation in the low-frequency peak or the high-frequency peak and measured the attractiveness of these stimuli to females in single-speaker and two-speaker phonotaxis tests. We obtained multiple lines of evidence that females were more selective for fine-temporal characteristics in the high-frequency peak. We discuss the potential implications of frequency channel-dependent temporal processing for signal evolution and suggest that additional neurophysiological investigations of the anuran auditory periphery will give important insights into how the nervous system partitions the encoding of multiple characteristics of complex signals.

Equivalence of coupled networks and networks with multimodal frequency distributions: Conditions for the bimodal and trimodal case.

Populations of oscillators can display a variety of synchronization patterns depending on the oscillators' intrinsic coupling and the coupling between them. We consider two coupled symmetric (sub)populations with unimodal frequency distributions. If internal and external coupling strengths are identical, a change of variables transforms the system into a single population of oscillators whose natural frequencies are bimodally distributed. Otherwise an additional bifurcation parameter κ enters the dynamics. By using the Ott-Antonsen ansatz, we rigorously prove that κ does not lead to new bifurcations, but that a symmetric two-coupled-population network and a network with a symmetric bimodal frequency distribution are topologically equivalent. Seeking for generalizations, we further analyze a symmetric trimodal network vis-à-vis three coupled symmetric unimodal populations. Here, however, the equivalence with respect to stability, dynamics, and bifurcations of the two systems no longer holds.

Amplitude dependence of image quality in atomically-resolved bimodal atomic force microscopy

In bimodal frequency modulation atomic force microscopy (FM-AFM), two flexural modes are excited simultaneously. We show atomically resolved images of KBr(100) in ambient conditions in both modes that display a strong correlation between the image quality and amplitude. We define the sum amplitude as the sum of the amplitudes of both modes. When the sum amplitude becomes larger than about 100 pm, the signal-to-noise ratio (SNR) drastically decreases. We propose that this is caused by the temporary presence of one or more water layers in the tip-sample gap. These water layers screen the short range interaction and must be displaced with each oscillation cycle. Decreasing the amplitude of either mode, however, increases the noise. Therefore, the highest SNR in ambient conditions is achieved when twice the sum amplitude is slightly less than the thickness of the primary hydration layer.

Acute renal failure in pregnancy at a tertiary level hospital in Mumbai: An epidemiological profile

Background: To study the clinical profile of pregnancy related acute renal failure, management and outcome in terms of cure, maternal morbidity and maternal ‐ fetal mortality. Methods: This is a prospective observational study carried out on hospitalized patients in our hospital over a period of fourteen months (August 2007 ‐ September 2008) after approval from the ethical clearance committee. Results: A total of 41 patients, with age ranging between 15 ‐ 45 years. The majority of the patients 25 (60.98%) were multigravida and 16 (39.02%) were primigravida. The bimodal frequency pattern were also observed in our study, first between 19 to 24 weeks of gestation and second around 31 to 36 weeks of gestation. The incidence of PR-ARF was about 1 in 270 pregnancies. Sepsis was the commonest cause of PR-ARF (46.34 %) followed by Toxaemia of Pregnancy (31.69%) and Haemorrhage (14.62%). The incidence of septic abortion as a cause of PR-ARF has declined to 7.31%. Oliguria was the commonest symptom (58.53%). Fluid overload was the most common complication encountered (33.33%). Conclusion: Incidence of PR-ARF is still high in our country as compared to western countries. Multigravidas were more commonly affected than primigravidas. Sepsis was the commonest cause of PR-ARF followed by toxaemia of pregnancy and haemorrhage. Maternal and fetal mortality were high , 17.07 % and 2.43 % respectively.

Hourglass-shaped specimen: compressive strength of concrete and mortar (numerical and experimental analyses)

Abstract Cylindrical specimens whose diameter is equal to half its height have been used worldwide. The statistical scattering in experimental testing of cementitious materials is a phenomenon known in literature and one reason is linked to the geometry of the specimens, which implies the possibility of different failure modes. This paper shows the evaluation of an hourglass-shaped sample , in which the highest stress occurs at the centre of the specimen, with negligible influence of stress distribuition from its ends. An amount of 260 cylindrical and hourglass samples were tested, with varying water/cement ratio and age. FEM analyses showed that stress in the central part of the hourglass specimens is 2.25 higher than that present at its ends. Modes of failure occured in differente ways in cylindrical specimens, whereas only one mode of failure was verified in hourglass specimens. The cylindrical samples showed bimodal frequency distribution, demonstrating the influence of the central part (material properties) and of its ends (boundary conditions), while the hourglass displayed a Gaussian distribution.

Brain responses reveal that infants' face discrimination is guided by statistical learning from distributional information.

Infants' perception of faces becomes attuned to the environment during the first year of life. However, the mechanisms that underpin perceptual narrowing for faces are only poorly understood. Considering the developmental similarities seen in perceptual narrowing for faces and speech and the role that statistical learning has been shown to play for speech, the current study examined whether and how learning from distributional information impacts face identity discrimination. We familiarized 6.5-month-old infants with exemplars of female faces taken from a morphed continuum going from one identity to another. Using event-related brain potentials (ERPs), we show that only infants who were familiarized with a bimodal frequency distribution, but not infants familiarized with a unimodal frequency distribution, discriminated between identities. These results are the first to demonstrate the influence of probabilistic information on infants' face identity discrimination, suggesting that statistical learning contributes to perceptual attunement for both faces and language.

Abstract P1-07-04: Etiologic heterogeneity in breast cancer across quantitative levels of estrogen receptor expression

Abstract Introduction: The clinical classification of breast cancer into at least four intrinsic subtypes has advanced targeted therapy and improved prognosis. However, for etiological classification, it has been proposed that breast cancer is comprised of just two main subtypes: basal-like and non-basal-like. Evidence for these two etiologic subtypes emerges strongly from bimodal age frequency distributions at diagnosis. In the absence of RNA-based intrinsic subtyping, estrogen receptor (ER) expression is a useful surrogate for these two distinct etiologic classes. Using data from the population-based Carolina Breast Cancer Study (CBCS), we examined evidence for a two-component (ER-positive vs. ER-negative) mixture model for breast cancer biologic/etiologic heterogeneity. Methods: Automated digital scoring of ER expression was performed on immunohistochemistry-stained tissue microarrays comprising 1,920 invasive breast cancer cases from CBCS. Clinical classification of ER status has changed over time as new data have emerged regarding optimal treatment-relevant thresholds, but optimal etiologic thresholds have not been established. Therefore, we considered ER status as a quantitative, categorical variable with cut points of <1% (ER-negative) vs. ≥1% (ER-positive), with ER-positive cases further categorized as highly positive (≥80-100%), intermediate (≥40-<80%), low (≥10-<40%) or borderline (≥1-<10%). Smoothed age frequency distributions at diagnosis (i.e., density plots) were constructed and logistic regression adjusted for age and race was conducted to assess associations between patient and tumor characteristics and level of ER positivity. Results: As expected for etiologically-distinct entities, ER-negative and highly ER-positive tumors showed predominantly unimodal early-onset and late-onset age distributions at diagnosis with peak frequencies near ages 50 and 70 years, respectively. However, tumors with low and intermediate positivity showed bimodal patterns, consistent with a mixture of two main subtypes. Consistent with these age distribution patterns, young age (<40 years) at diagnosis was associated with an elevated odds ratio (OR) for low positive (OR 1.8; 95% CI 1.1-2.9), borderline (OR 1.9; 95% CI 1.1-3.3) and ER-negative disease (OR 2.2; 95% CI 1.5-3.2). Relative to highly ER-positive tumors, low ER-positive tumors were more likely to be node-positive (OR 1.4; 95% CI 1.0-1.9), higher grade (combined grade III; OR 1.9; 95% CI 1.3-2.9), and were more likely to harbor a p53 mutation (OR 2.0; 95% CI 1.2-3.5). Conclusions: While etiologic differences between dichotomized ER-negative and ER-positive breast cancer categories have been well described in many epidemiologic studies, differences in breast cancer etiology across quantitative levels of ER expression have not been so well-characterized. In this study, we report that ER-positive tumors with low positivity share etiologic features of ER-negative tumors, including young age at diagnosis and aggressive tumor characteristics. These data provide additional support for a two-component breast cancer mixture model, with quantitative level of ER positivity reflecting the relative distributions of ER-positive and ER-negative tumor populations. Citation Format: Allott EH, Tse C-K, Carey L, Anderson WF, Olshan AF, Troester MA. Etiologic heterogeneity in breast cancer across quantitative levels of estrogen receptor expression. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-04.

Frequency variability of standing Alfvén waves excited by fast mode resonances in the outer magnetosphere

AbstractCoupled fast mode resonances (cFMRs) in the outer magnetosphere, between the magnetopause and a turning point, are often invoked to explain observed discrete frequency field line resonances. We quantify their frequency variability, applying cFMR theory to a realistic magnetic field model and magnetospheric density profiles observed over almost half a solar cycle. Our calculations show that cFMRs are most likely around dawn, since the plasmaspheric plumes and extended plasmaspheres often found at noon and dusk can preclude their occurrence. The relative spread (median absolute deviation divided by the median) in eigenfrequencies is estimated to be 28%, 72%, and 55% at dawn, noon, and dusk, respectively, with the latter two chiefly due to density. Finally, at dawn we show that the observed bimodal density distribution results in bimodal cFMR frequencies, whereby the secondary peaks are consistent with the so‐called “CMS” frequencies that have previously been attributed to cFMRs.

Major depressive disorder as a nonlinear dynamic system: bimodality in the frequency distribution of depressive symptoms over time.

BackgroundA defining characteristic of Major Depressive Disorder (MDD) is its episodic course, which might indicate that MDD is a nonlinear dynamic phenomenon with two discrete states. We investigated this hypothesis using the symptom time series of individual patients.MethodsIn 178 primary care patients with MDD, the presence of the nine DSM-IV symptoms of depression was recorded weekly for two years. For each patient, the time-series plots as well as the frequency distributions of the symptoms over 104 weeks were inspected. Furthermore, two indicators of bimodality were obtained: the bimodality coefficient (BC) and the fit of a 1- and a 2-state Hidden Markov Model (HMM).ResultsIn 66 % of the sample, high bimodality coefficients (BC > .55) were found. These corresponded to relatively sudden jumps in the symptom curves and to highly skewed or bimodal frequency distributions. The results of the HMM analyses classified 90 % of the symptom distributions as bimodal.ConclusionsA two-state pattern can be used to describe the course of depression symptoms in many patients. The BC seems useful in differentiating between subgroups of MDD patients based on their life course data.

SENSITIVITY OF BOTRYTIS CINEREA FROM 'FORELLE' PEARS IN SOUTH AFRICA TO BENOMYL, IPRODIONE AND PYRIMETHANIL

‘Forelle’ pears are an important component of pome fruit exported from South Africa. However, postharvest grey mould caused by the pathogen Botrytis cinerea can be a significant problem in this cultivar, particularly as decay is often only detected once the pears reach the export markets. Fungicides applied at full bloom and postharvest are important in the integrated management of grey mould in pears, however, loss of fungicide sensitivity is common in B. cinerea. In this study, B. cinerea was isolated from long-term stored ‘Forelle’ pears from orchards in the Ceres production area of South Africa, showing calyx-end Botrytis. The baseline sensitivity of a sub-population (n=49) not previously exposed to botryticides was determined on a minimal medium amended with technical grade pyrimethanil. This population had a bimodal frequency distribution of pyrimethanil EC50 values, which ranged from 0.06 to 0.36 mg L-1, with a mean EC50 value of 0.13 mg L-1. The sensitivity of B. cinerea isolates (n=166) to benomyl, iprodione and pyrimethanil was tested using discriminatory concentrations of 3 and 5 mg L-1 for each fungicide. None of the isolates grew on the pyrimethanil amended media, whereas one isolate grew on benomyl at 5 mg L-1 (RF=0.6%), and two isolate grew on iprodione at 5 mg L-1 (RF=1.2%). From this study we can conclude that the population tested is sensitive to the three fungicides, and these fungicides can be used to manage postharvest grey mould in the Ceres production area.