Significant Effect Of Frequency Research Articles

Responses of underground clonal storage to mowing of the alien clonal weed species Oxalis articulata.

Oxalis articulata, an alien clonal plant species, is widely cultivated in China as an ornamental species, and has escaped and became naturalized. Belowground storage in tubers of O. articulata may play a key role for the potential invasion. In this study, we investigated the responses of its clonal resource storage strategy to mowing, aiming to uncover the mechanism underlying their invasion from a perspective of clonal storage. We examined the changes of biomass in different organs, biomass allocation, and several functional traits of roots, tubers and leaves in O. articulata by conducting a greenhouse experiment. The results showed that significant main and interactive effects of mowing intensity and mowing frequency on some functional traits of leaves and roots were found. In contrast, tuber biomass and total biomass did not vary under different mowing treatments. The frequent mowing significantly increased the biomass allocation to tubers. These findings demonstrated that clonal storage, to some extent, could enhance the resistance of O. articulata to environmental disturbance, which might promote its invasiveness.

Busting a myth with the Bayes Factor

Abstract Psycholinguistic researchers identify linguistic variables and assess if they affect cognitive processes. One such variable is letter bigram frequency, or the frequency with which a given letter pair co-occurs in an orthography. While early studies reported that bigram frequency affects visual lexical decision, subsequent, well-controlled studies not shown this effect. Still, researchers continue to use it as a control variable in psycholinguistic experiments. We propose two reasons for the persistence of this variable: (1) Reporting no significant effect of bigram frequency cannot provide evidence for no effect. (2) Despite empirical work, theoretical implications of bigram frequency are largely neglected. We perform Bayes Factor analyses to address the first issue. In analyses of existing large-scale databases, we find no effect of bigram frequency in lexical decision in the British Lexicon Project, and some evidence for an inhibitory effect in the English Lexicon Project. We find strong evidence for an effect in reading aloud. This suggests that, for lexical decision, the effect is unstable, and may depend on item characteristics and task demands rather than reflecting cognitive processes underlying visual word recognition. We call for more consideration of theoretical implications of the presence or absence of a bigram frequency effect.

In-situ activity of α-amylase in the presence of controlled-frequency moderate electric fields

Studies on the effects of electric fields on enzymatic activity have typically focused on post-treatment residual activity. However, information on their effects on in-situ activity is scant. The objective of this study was to investigate the effect of controlled-frequency Moderate Electric Fields (MEF) on α-amylase activity. Relative α-amylase activities were measured in-situ in the presence of an electric field (1 V/cm, 1 Hz-1MHz) at 60 °C, with a zero electric field at the same temperature serving as a control treatment. Results show a significant nonthermal effect of electric field frequency on α-amylase activity, with up to 41% enhancement of the activity in the 1–60 Hz frequency window. At higher frequencies, activity was either unaffected, or slightly inhibited by the presence of the electric field. Molecular dynamics simulation results show that in the 1–60 Hz frequency window, the translational electrophoretic enzyme displacement approaches the intermolecular spacing of water. Interestingly, enzyme rotational motion transitions from oscillatory behavior to full rotation below 60 Hz. Application of higher frequencies restricts the electrophoretic displacement of the enzyme due to rapid reversal of the direction of the electric field.

Mechanical stress increases brain amyloid β, tau, and α-synuclein concentrations in wild-type mice

IntroductionExposure to traumatic brain injury is a core risk factor that predisposes an individual to sporadic neurodegenerative diseases. We provide evidence that mechanical stress increases brain levels of hallmark proteins associated with neurodegeneration. MethodsWild-type mice were exposed to multiple regimens of repetitive mild traumatic brain injury, generating a range of combinations of impact energies, frequencies, and durations of exposure. Brain concentrations of amyloid β 1–42 (Aβ1–42), total tau, and α-synuclein were measured by sandwich enzyme-linked immunosorbent assay. ResultsThere was a highly significant main effect of impact energy, frequency, and duration of exposure on Aβ1–42, tau, and α-synuclein levels (P < .001), and a significant interaction between impact energy and duration of exposure for Aβ1–42 and tau (P < .001), but not for α-synuclein. DiscussionDose-dependent and cumulative influence of repetitive mild traumatic brain injury–induced mechanical stress may trigger and/or accelerate neurodegeneration by pushing protein concentration over the disease threshold.

THE IMPACT OF MOTIVATION IN USING ONLINE SHOPPING CART ON THE FREQUENCY OF USING ONLINE SHOPPING CART WITH THE ONLINE SHOPPING FREQUENCT

The number of e-commerce in Indonesia allows consumers to make purchases, simply by selecting and putting the desired item in the online shopping cart and proceed with the payment process then the consumer just waiting for the item he wants to arrive at home. This study aims to determine the influence of online shopping cart use motivation to the frequency of online shopping cart use with the frequency of online buying. This research was conducted by distributing the questionnaire online to 120 respondents. From the results of this study conducted data processing with AMOS 23.0 to prove the influence of each research variable. The result of research shows that current purchase intent, taking advantage of price promotion has positive and significant effect of frequency of online shopping cart use and current purchase intent have a positive and significant effect of frequency of online buying. While entertainment purpose, organizational intent, and research and information search have no significant effect on the frequency of online shopping cart use.

Study of fingerprints in Argentina population for application in personal identification

The fingerprints of the Buenos Aires and Chubut provinces in Argentina have been studied, with the aim of knowing and quantifying the variability of these features, which are used in the identification process. The data studied for this research was obtained from 330 individuals, of both sexes, from two Argentinian population samples (170 individuals from Buenos Aires and 160 from Chubut), which amounts to a total of 3300 fingerprints. The different types of minutiae were located, identified, and visually quantified in four areas on the fingerprint. Two perpendicular axes were drawn whose intersection was located in the center of fingerprint. In addition, a circle was defined on these quadrants whose radius cut fifteen ridges. This method divides the fingerprints into four quadrants with two sectors apiece. The results obtained for both populations were compared statistically with those published previously for an Argentinian population sample, which had been collected using the same methodology. Therefore, Argentina becomes the country with the most information in this matter.For both populations, the highest frequencies were of ridge endings, followed by bifurcations and convergences. In this study of minutiae, statistically significant differences were found between the area of the fingerprint (inside and outside the circle), males and females, and types of main pattern for both samples. However, although the results show common patterns in the distribution of minutiae, there are also significant differences between populations. This reveals a significant ancestral and frequency effect of the minutiae, which would indicate that the minutiae are more genetically dependent than has been suspected so far. Furthermore, the non-equiprobability found for the frequency of the types of minutiae indicates that the weight provided by these characteristics is not the same when applied in identification processes, whether used quantitatively (numerical standard) or qualitatively (holistic method).

Verbal short-term memory and language impairments in Cantonese speakers after stroke

Purpose: The study examined the relationship between verbal short-term memory (STM) and language impairment in Cantonese speakers after stroke. It is hypothesised that Cantonese speakers with left-hemisphere (LH) stroke would perform worse than those with right hemisphere (RH) stroke and normal controls. Specific linguistic factors of Cantonese might affect results in the tasks.Method: Fifteen participants with LH stroke, 10 with RH stroke and 25 healthy controls were tested with auditory–verbal immediate serial recall (ISR) tasks and auditory linguistic tasks. All stroke participants were assessed with the Cantonese version of Western Aphasia Battery (CAB).Result: The LH group performed significantly worse than the RH and healthy control groups in the auditory verbal ISR and auditory linguistic tasks. There were significant lexicality, frequency and imageability effects in most tasks. Auditory discrimination and word comprehension tasks, but not the auditory word recognition task had correlations with ISR tasks.Conclusion: Verbal STM and language performance of Cantonese-speakers with history of LH stroke were inferior to RH stroke and healthy controls. The effects of lexicality, word frequency and imageability on verbal STM memory performance were found. Cantonese tones have effects on performance in auditory word recognition task, similar to onset, nucleus and rime.

The impact of word frequency on peripheral processes during handwriting: A matter of age.

Although several studies have found that the sublexical route of spelling has an effect on handwriting movements, the ability of lexical variables to modulate peripheral processes during writing is less clear. This study addresses the hypothesis that word frequency affects writing durations only during writing acquisition, and that at some point of development, the handwriting system becomes a relatively autonomous system unaffected by lexical variables. Spanish children attending Grades 2, 4, and 6 performed a spelling-to-dictation and a copy task in which word frequency was manipulated. Results revealed that written latencies decreased with age, especially between Grades 2 and 4, and that writing durations decreased between these two groups. All these measures were longer during copying but the effect of task on written latencies and in-air pen trajectories was smaller for older children. Crucially, a significant word frequency effect on writing durations was observed only in Grade 2. This effect was marginally significant in Grade 4 and disappeared in Grade 6. However, all groups showed a similar effect of word frequency on written latencies. These findings suggest that lexical processes impact peripheral processes during writing acquisition and that this influence diminishes to eventually disappear at some point in development.

Chinese L2 Learners’ Depth of Vocabulary Knowledge and Its Role in Reading Comprehension

AbstractUsing a Chinese Word Associates Test (WAT‐C), this study examined the vocabulary depth of second language learners of Chinese and its contribution to the learners’ reading comprehension. Results showed no significant effects of word frequency, word class (i.e., adjectives vs. verbs), and type of association relationships (i.e., paradigmatic vs. syntagmatic) on learners’ WAT‐C performance. More important, vocabulary depth was found to be a significant and unique predictor of reading comprehension over and above vocabulary size. On the other hand, the relative contributions of vocabulary depth and size depended on what types of texts were read and what comprehension skills were assessed. Specifically, for the long passage comprehension task with questions testing literal comprehension, vocabulary size was a more important predictor, whereas for the short passage comprehension task with questions testing inferencing, vocabulary depth was a more important predictor. These findings were discussed in light of the different levels of lexical complexity between the short and long passages and the different cognitive processing demands the questions of the two comprehension tasks placed on learners.

Hyperprolactinemia in end-stage renal disease and effects of frequent hemodialysis.

End-stage renal disease is associated with elevations in circulating prolactin concentrations, but the association of prolactin concentrations with intermediate health outcomes and the effects of hemodialysis frequency on changes in serum prolactin have not been examined. The FHN Daily and Nocturnal Dialysis Trials compared the effects of conventional thrice weekly hemodialysis with in-center daily hemodialysis (6 days/week) and nocturnal home hemodialysis (6 nights/week) over 12 months and obtained measures of health-related quality of life, self-reported physical function, mental health and cognition. Serum prolactin concentrations were measured at baseline and 12-month follow-up in 70% of the FHN Trial cohort to examine the associations among serum prolactin concentrations and physical, mental and cognitive function and the effects of hemodialysis frequency on serum prolactin. Among 177 Daily Trial and 60 Nocturnal Trial participants with baseline serum prolactin measurements, the median serum prolactin concentration was 65 ng/mL (25th-75th percentile 48-195 ng/mL) and 81% had serum prolactin concentrations >30 ng/mL. While serum prolactin was associated with sex (higher in women), we observed no association between baseline serum prolactin and age, dialysis vintage, and baseline measures of physical, mental and cognitive function. Furthermore, there was no significant effect of hemodialysis frequency on serum prolactin in either of the two trials. Serum prolactin concentrations were elevated in the large majority of patients with ESRD, but were not associated with several measures of health status. Circulating prolactin levels also do not appear to decrease in response to more frequent hemodialysis over a one-year period.

Cyclic loading of human articular cartilage: The transition from compaction to fatigue

Osteoarthritis and articular cartilage injuries are common conditions in human joints and a frequent cause of pain and disability. Unfortunately, cartilage is avascular and has limited capabilities for self-repair. Despite the societal impact, there is little information on the dynamic process of cartilage degeneration. We performed a series of cyclic unconfined compression tests motivated by in vivo loading conditions and designed to generate mechanical fatigue. We examined the functional (both stress–stretch and creep) responses of the tissue after recovery from a specified number of loading cycles, as well as histology and second harmonic generation microscopy images. The effect of compaction was complimented by the effect of fatigue in our unconfined compression tests. A three-way, repeated-measures mixed model ANOVA showed significant differences between loading with a physiologically relevant low magnitude, and two more severe loading magnitudes, in terms of the resulting specimen stiffness, time to equilibrium and thickness. There was a statistically significant effect of loading frequency on a specimen's time to equilibrium and significant interaction of force and frequency on specimen thickness and time to equilibrium. Increasing the number of loading cycles significantly impacted a specimen's effective stiffness and resulting thickness. We attribute permanent loss of mechanical function under cyclic loading to rearrangement and disruption of the collagen network and resulting proteoglycan (PG) aggregation, as seen in histological and second harmonic generation images, as a result of induced mechanical fatigue.

Deep litter removal frequency rate influences on greenhouse gas emissions from barns for beef heifers and from manure stores

The emission of greenhouses gases (GHG) from ruminant production systems needs to be reduced. This can be achieved partly by better manure management, particularly for deep litter (DL) systems. Two contrasting removal frequency rates (1×, every 63.5±3.5days; and 3×, every 23.1±1.5days) were compared in a DL system for Belgian blue double-muscled heifers, focusing on CO2, CH4 and N2O emissions from the barn and during two manure storage periods, one mainly in autumn and the other mainly in winter. No significant effect (p=0.447) of manure removal frequency on total GHG emissions was observed (1×: 10.2±3.5; 3×: 8.7±2.2kg CO2 eq. kg−1 live weight gain).The manure contributed significantly to total GHG emissions (average of 38.9±8.0% of CO2 eq.), emissions from the barn (4.0±0.7%) and manure store included (34.9±8.7%). Higher emissions (time 4.8 in CO2 eq.) from manure were observed when it was stored during the warmer period than the colder one. Large variations in emission pattern with the manure removal frequency rates were also observed, leading potentially (not measured) to higher emissions from the 1× treatment than the 3× treatment for a longer storage period than the one tested in this experiment (63±1days). Given the experimental choices, the variations in emission pattern observed indicated that mitigation options for GHG emissions from the barn and manure store related to manure removal frequency depend on manure storage duration and that keeping deep litter manure in barns without intermediate storage before spreading should be investigated. These options need to be confirmed through emission measurement during and after manure spreading in order to avoid a trade-off between emission stages. The relevance of such options in terms of agronomical concerns needs to be confirmed.

Changes in olfactory bulb volume following lateralized olfactory training.

Repeated exposure to odors modifies olfactory function. Consequently, "olfactory training" plays a significant role in hyposmia treatment. In addition, numerous studies show that the olfactory bulb (OB) volume changes in disorders associated with olfactory dysfunction. Aim of this study was to investigate whether and how olfactory bulb volume changes in relation to lateralized olfactory training in healthy people. Over a period of 4months, 97 healthy participants (63 females and 34 males, mean age: 23.74±4.16years, age range: 19-43years) performed olfactory training by exposing the same nostril twice a day to 4 odors (lemon, rose, eucalyptus and cloves) while closing the other nostril. Before and after olfactory training, magnetic resonance imaging (MRI) scans were performed to measure OB volume. Furthermore, participants underwent lateralized odor threshold and odor identification testing using the "Sniffin' Sticks" test battery.OB volume increased significantly after olfactory training (11.3% and 13.1% respectively) for both trained and untrained nostril. No significant effects of sex, duration and frequency of training or age of the subjects were seen. Interestingly, PEA odor thresholds worsened after training, while olfactory identification remained unchanged.These data show for the first time in humans that olfactory training may involve top-down process, which ultimately lead to a bilateral increase in olfactory bulb volume.

Incidental vocabulary acquisition from reading-only and reading-while-listening: a multi-dimensional approach

ABSTRACTThis study compared the effects of the reading-while-listening condition and the reading-only condition on English as a foreign language (EFL) learners’ acquisition of the four dimensions of vocabulary knowledge: form recognition, grammar recognition, meaning recall, and collocation recognition. Accordingly, 24 words within four frequency groups were selected and total 60 Chinese EFL students were enrolled. The results revealed that new words could be learned incidentally in both conditions. However, more words were learned in the reading-while-listening condition. A significant effect of word exposure frequency on incidental vocabulary gains was observed for acquisition of word form and grammar, but no significant effect was found for acquisition of meaning and collocation. Although the reading-while-listening condition was more effective for incidental vocabulary acquisition than the reading-only condition, it appeared that for these two conditions to be a valuable source for incidental vocabulary acquisition, both word exposure frequency and elaborate word processing were needed.

Average optimal DPOAE primary tone levels in normal-hearing adults

Objective: Despite great progress towards optimizing DPOAE primary tone characteristics, factors such as stimulus and intra-subject emission variability have not been addressed. The purpose of this study was to identify optimal primary tone level relationships when these sources of variability were acknowledged, and to identify any influences of test frequency. Design: Following coupler-based measurements assessing primary tone level stability, two experiments were conducted. In experiment 1, DPOAE test-retest reliability without probe replacement was measured for f2 = 1–6 kHz with L1 = L2 = 65 dB SPL. In experiment 2, optimal L1-L2 relationships were identified for f2 = 1–6 kHz. For 20 ≤ L2 ≤ 75 dB SPL, L1 was varied 15 dB SPL above and below the recommendation of L1 = 0.4 L2 + 39 [dB SPL]. Study sample: Eleven normal-hearing adults participated in experiment 1. Thirty normal-hearing adults participated in experiment 2. Results: Stimulus variability did not exceed 0.1 dB SPL. DPOAE reliability testing revealed an across-frequency mean standard error of measurement of 0.52 dB SPL. The average optimal L1-L2 relationship was described by L1 = 0.49 L2 + 41 [dB SPL]. A significant effect of frequency was identified for 6 kHz. Conclusion: Including relevant sources of variability improves internal validity of a primary tone level optimization formula.

The behavioral effects of frequent nightmares on objective stress tolerance.

Frequent nightmares have been linked to daily distress using self-report measures. The present study investigated the impact of frequent nightmares on a stressful cognitive test requiring participants to perform additions of 2 previously displayed single digit numbers from a number series, where display latency between digits becomes increasingly short—the Paced Visual Serial Addition Task-Computerized (PVSAT-C). Participants experiencing frequent nightmares (n = 43) and controls (n = 42) were compared on PVSAT-C performance. A significant main effect of nightmare frequency was observed with participants in the frequent nightmare group enduring the task for a shorter duration than controls (a behavioral measure of stress tolerance). Results suggest that individuals experiencing frequent nightmares have a reduced tolerance for stressors, leading to increased daily vulnerability to stressful stimuli. This study confirms previous findings linking nightmares and daily distress and extends the literature by providing objective evidence for the link between nightmares and reduced stress tolerance through behavioral testing. These findings highlight nightmares as a salient target for clinical intervention.

Frequency-dependent changes in amplitude of low-frequency oscillations in depression: A resting-state fMRI study

ObjectiveWe conducted this fMRI study to examine whether the alterations in amplitudes of low-frequency oscillation (LFO) of major depressive disorder (MDD) patients were frequency dependent. Materials and methodsThe LFO amplitudes (as indexed by amplitude of low-frequency fluctuation [ALFF] and fractional ALFF [fALFF]) within 4 narrowly-defined frequency bands (slow-5: 0.01–0.027Hz, slow-4: 0.027–0.073Hz, slow-3: 0.073–0.198Hz, and slow-2: 0.198–0.25Hz) were computed using resting-state fMRI data of 35 MDD patients and 32 healthy subjects. Repeated-measures analysis of variance (ANOVA) was performed on ALFF and fALFF both within the low frequency bands of slow-4 and slow-5 and within all of the four bands. ResultsWe observed significant main effects of group and frequency on ALFF and fALFF in widely distributed brain regions. Importantly, significant group and frequency interaction effects were observed in the ventromedial prefrontal cortex, inferior frontal gyrus, precentral gyrus, in a left-sided fashion, the bilateral posterior cingulate and precuneus, during ANOVA both within slow-4 and slow-5 bands and within all the frequency bands. ConclusionsThe results suggest that the alterations of LFO amplitudes in specific brain regions in MDD patients could be more sensitively detected in the slow-5 rather than the slow-4 bands. The findings may provide guidance for the frequency choice of future resting-state fMRI studies of MDD.

The usage and spread of sentence-internal capitalization in Early New High German: A multifactorial approach

AbstractSentence-internal capitalization of nouns is a characteristic of written Standard German. The sixteenth and seventeenth centuries have been identified as the crucial period for the development of this graphemic convention. Previous studies have shown that animacy played a major role in the spread of sentence-internal capitalization. On the basis of the transregional SiGS-corpus consisting of 18 protocols of witch trials (hand-)written between 1588 and 1630, we propose word frequency as an additional factor and test for its interaction with animacy. Our data reveal that the proportion of capitalized words denoting humans and animate concepts increases rapidly, while the capitalization of lexemes referring to concrete and abstract concepts remains stable at a lower level. A binomial mixed-effects model shows a highly significant effect of frequency and a significant interaction between frequency and animacy. In sum, our data show how cognitive, pragmatic, and usage factors conspire in the gradual emergence of a graphemic convention. We therefore argue that the previously neglected graphemic dimension can add important insights to an empirically based theory of the language-cognition interface.

Early and Late Electrophysiological Effects of Distractor Frequency in Picture Naming: Reconciling Input and Output Accounts.

The "distractor-frequency effect" refers to the finding that high-frequency (HF) distractor words slow picture naming less than low-frequency distractors in the picture-word interference paradigm. Rival input and output accounts of this effect have been proposed. The former attributes the effect to attentional selection mechanisms operating during distractor recognition, whereas the latter attributes it to monitoring/decision mechanisms operating on distractor and target responses in an articulatory buffer. Using high-density (128-channel) EEG, we tested hypotheses from these rival accounts. In addition to conducting stimulus- and response-locked whole-brain corrected analyses, we investigated the correct-related negativity, an ERP observed on correct trials at fronto-central electrodes proposed to reflect the involvement of domain general monitoring. The whole-brain ERP analysis revealed a significant effect of distractor frequency at inferior right frontal and temporal sites between 100 and 300-msec post-stimulus onset, during which lexical access is thought to occur. Response-locked, region of interest (ROI) analyses of fronto-central electrodes revealed a correct-related negativity starting 121 msec before and peaking 125 msec after vocal onset on the grand averages. Slope analysis of this component revealed a significant difference between HF and low-frequency distractor words, with the former associated with a steeper slope on the time window spanning from 100 msec before to 100 msec after vocal onset. The finding of ERP effects in time windows and components corresponding to both lexical processing and monitoring suggests the distractor frequency effect is most likely associated with more than one physiological mechanism.

Broca's region and Visual Word Form Area activation differ during a predictive Stroop task

Competing theories attempt to explain the function of Broca's area in single word processing. Studies have found the region to be more active during processing of pseudo words than real words and during infrequent words relative to frequent words and during Stroop (incongruent) color words compared to Non-Stroop (congruent) words. Two related theories explain these findings as reflecting either “cognitive control” processing in the face of conflicting input or a linguistic prediction error signal, based on a predictive coding approach. The latter implies that processing cost refers to violations of expectations based on the statistical distributions of input. In this fMRI experiment we attempted to disentangle single word processing cost originating from cognitive conflict and that stemming from predictive expectation violation. Participants (N = 49) responded to whether the words “GREEN” or “RED” were displayed in green or red (incongruent vs congruent colors). One of the colors, however, was presented three times as often as the other, making it possible to study both congruency and frequency effects independently. Auditory stimuli saying “GREEN” or “RED” had the same distribution, making it possible to study frequency effects across modalities. We found significant behavioral effects of both incongruency and frequency. A significant effect (p < .05 FWE) of incongruency was found in Broca's region, but no effect of frequency was observed and no interaction. Conjoined effects of incongruency and frequency were found in parietal regions as well as in the Visual Word Form Area (VWFA). No interaction between perceptual modality and frequency was found in VWFA suggesting that the region is not strictly visual. These findings speak against a strong version of the prediction error processing hypothesis in Broca's region. They support the idea that prediction error processes in the intermediate timeframe are allocated to more posterior parts of the brain.