611 research outputs found
Lexical richness in adolescent writing, insights from the classroom: An L1 vocabulary development study
This thesis constitutes a mixed-methods enquiry into how vocabulary develops across adolescence, within the context of New Zealand secondary schools. A quantitative approach was adopted to investigate vocabulary use in authentic written essays produced by secondary school English students (N=141) belonging to three age groups: 13-14, 15-16, and 17-18, from eight schools. Essays were analysed for the following three lexical richness features: lexical variation, lexical sophistication, and lexical density. With links between these lexical richness features and vocabulary size/skill in vocabulary use (Vermeer, 2000; Ravid & Zilberbuch, 2003; Malvern, Richards, Chipere, & Durán, 2009), signs of development were studied through comparison of scores across the three age groups. Quantitative findings indicate significant lexical development across year levels in the data set. Furthermore, the findings suggest that within the period of adolescence there is an even more specific period in which substantial development takes place: 15-18 years, or later adolescence.
The qualitative aspect of this study focussed on identifying teacher perspectives on influences from within the secondary school context impacting on vocabulary development during this significant period of acquisition. Seven secondary school English teachers were interviewed on the subject of lexical development as it occurs within the schooling environment. Contributions from the school curriculum to vocabulary acquisition were observed, with spikes in curriculum difficulty from year 11 (age 15-16) onward corresponding with the developmental spike observed in the quantitative data further supporting this observation. Non-schooling related influences were also identified, including cognitive development, reading habits, and attitude and orientation toward vocabulary.
The present study contributes to the growing field of later language acquisition through identification of a possible period of heightened development within the adolescent years. Importantly, it also highlights factors in students’ everyday school lives which may contribute to their lexical development, raising implications both for those wishing to promote lexical development within the secondary school population, and more globally for our understanding of how heightened development occurs during this period. The study concludes with implications for theory, research and practice, together with limitations of the study and future research directions arising from this research
Interpersonal Violence and Contraceptive Method Use by Women Sex Workers
Objective
More than one-half of women sex workers (sex workers) in the United States experience interpersonal violence, defined as physical or sexual violence, by sexual partners, including clients or intimate partners. Women experiencing interpersonal violence by intimate partners often choose hidden, woman-controlled contraception (e.g., intrauterine devices, pills, or sterilization) because fear of violence can impede condom negotiation. Yet, little is known about how interpersonal violence relates to contraception among sex workers who may have different sexual partner perpetrators (clients and intimate partners). The purpose of this study was to examine associations between interpersonal violence perpetrated by clients or intimate partners and contraceptive use. Study Design
Data are from an observational, prospective cohort of sex workers, aged 18 to 49 in Baltimore, Maryland (N = 218). Bivariate and multivariable logistic regression were used to assess associations between lifetime interpersonal violence and past 3-month contraceptive use. The outcome was any woman-controlled contraceptive use versus partner-controlled or no contraception. Results
Nearly all sex workers (96.5%) reported contraceptive use, with most using male condoms (69%), nearly one-half using woman-controlled methods (43%), and 25% using dual methods (e.g., condoms and a woman-controlled method). Lifetime experiences of interpersonal violence by clients (58%) and intimate partners (52%) were prevalent. Sex workers who experienced interpersonal violence by intimate partners had over twice the odds of woman-controlled contraceptive use (adjusted odds ratio, 2.48; 95% confidence interval, 1.36–4.54). Conclusions
Findings highlight the importance of relationship context in the associations between interpersonal violence and use of woman-controlled contraceptive methods among sex workers, because only violence experiences by intimate partners were associated with increased odds of woman-controlled contraceptive method use
Uncovering the Multibiome Environmental and Earth System Legacies of Past Human Societies
It has been argued that we have now entered the Anthropocene, a proposed epoch in which humans are having a dominant impact on the Earth system. While some geologists have sought to formalize the Anthropocene as beginning in the mid-twentieth century, its social, geophysical, and environmental roots undoubtedly lie deeper in the past. In this review, we highlight the ways in which human activities across the major biomes of our planet significantly altered parts of the Earth system prior to the Industrial Age. We demonstrate ways in which novel, multidisciplinary approaches can provide detailed insights into long-term human–environment–Earth system interactions. We argue that there is clear evidence for lasting Earth system legacies of pre-Industrial human societies and that archaeology, paleoecology, and historical ecology can provide important, practical insights to help navigate current and future relationships with the planet in more equitable and sustainable ways
Readout of a quantum processor with high dynamic range Josephson parametric amplifiers
We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in
which the active nonlinear element is implemented using an array of rf-SQUIDs.
The device is matched to the 50 environment with a Klopfenstein-taper
impedance transformer and achieves a bandwidth of 250-300 MHz, with input
saturation powers up to -95 dBm at 20 dB gain. A 54-qubit Sycamore processor
was used to benchmark these devices, providing a calibration for readout power,
an estimate of amplifier added noise, and a platform for comparison against
standard impedance matched parametric amplifiers with a single dc-SQUID. We
find that the high power rf-SQUID array design has no adverse effect on system
noise, readout fidelity, or qubit dephasing, and we estimate an upper bound on
amplifier added noise at 1.6 times the quantum limit. Lastly, amplifiers with
this design show no degradation in readout fidelity due to gain compression,
which can occur in multi-tone multiplexed readout with traditional JPAs.Comment: 9 pages, 8 figure
Measurement-Induced State Transitions in a Superconducting Qubit: Within the Rotating Wave Approximation
Superconducting qubits typically use a dispersive readout scheme, where a
resonator is coupled to a qubit such that its frequency is qubit-state
dependent. Measurement is performed by driving the resonator, where the
transmitted resonator field yields information about the resonator frequency
and thus the qubit state. Ideally, we could use arbitrarily strong resonator
drives to achieve a target signal-to-noise ratio in the shortest possible time.
However, experiments have shown that when the average resonator photon number
exceeds a certain threshold, the qubit is excited out of its computational
subspace, which we refer to as a measurement-induced state transition. These
transitions degrade readout fidelity, and constitute leakage which precludes
further operation of the qubit in, for example, error correction. Here we study
these transitions using a transmon qubit by experimentally measuring their
dependence on qubit frequency, average photon number, and qubit state, in the
regime where the resonator frequency is lower than the qubit frequency. We
observe signatures of resonant transitions between levels in the coupled
qubit-resonator system that exhibit noisy behavior when measured repeatedly in
time. We provide a semi-classical model of these transitions based on the
rotating wave approximation and use it to predict the onset of state
transitions in our experiments. Our results suggest the transmon is excited to
levels near the top of its cosine potential following a state transition, where
the charge dispersion of higher transmon levels explains the observed noisy
behavior of state transitions. Moreover, occupation in these higher energy
levels poses a major challenge for fast qubit reset
Overcoming leakage in scalable quantum error correction
Leakage of quantum information out of computational states into higher energy
states represents a major challenge in the pursuit of quantum error correction
(QEC). In a QEC circuit, leakage builds over time and spreads through
multi-qubit interactions. This leads to correlated errors that degrade the
exponential suppression of logical error with scale, challenging the
feasibility of QEC as a path towards fault-tolerant quantum computation. Here,
we demonstrate the execution of a distance-3 surface code and distance-21
bit-flip code on a Sycamore quantum processor where leakage is removed from all
qubits in each cycle. This shortens the lifetime of leakage and curtails its
ability to spread and induce correlated errors. We report a ten-fold reduction
in steady-state leakage population on the data qubits encoding the logical
state and an average leakage population of less than
throughout the entire device. The leakage removal process itself efficiently
returns leakage population back to the computational basis, and adding it to a
code circuit prevents leakage from inducing correlated error across cycles,
restoring a fundamental assumption of QEC. With this demonstration that leakage
can be contained, we resolve a key challenge for practical QEC at scale.Comment: Main text: 7 pages, 5 figure
BHPR research: qualitative1. Complex reasoning determines patients' perception of outcome following foot surgery in rheumatoid arhtritis
Background: Foot surgery is common in patients with RA but research into surgical outcomes is limited and conceptually flawed as current outcome measures lack face validity: to date no one has asked patients what is important to them. This study aimed to determine which factors are important to patients when evaluating the success of foot surgery in RA Methods: Semi structured interviews of RA patients who had undergone foot surgery were conducted and transcribed verbatim. Thematic analysis of interviews was conducted to explore issues that were important to patients. Results: 11 RA patients (9 ♂, mean age 59, dis dur = 22yrs, mean of 3 yrs post op) with mixed experiences of foot surgery were interviewed. Patients interpreted outcome in respect to a multitude of factors, frequently positive change in one aspect contrasted with negative opinions about another. Overall, four major themes emerged. Function: Functional ability & participation in valued activities were very important to patients. Walking ability was a key concern but patients interpreted levels of activity in light of other aspects of their disease, reflecting on change in functional ability more than overall level. Positive feelings of improved mobility were often moderated by negative self perception ("I mean, I still walk like a waddling duck”). Appearance: Appearance was important to almost all patients but perhaps the most complex theme of all. Physical appearance, foot shape, and footwear were closely interlinked, yet patients saw these as distinct separate concepts. Patients need to legitimize these feelings was clear and they frequently entered into a defensive repertoire ("it's not cosmetic surgery; it's something that's more important than that, you know?”). Clinician opinion: Surgeons' post operative evaluation of the procedure was very influential. The impact of this appraisal continued to affect patients' lasting impression irrespective of how the outcome compared to their initial goals ("when he'd done it ... he said that hasn't worked as good as he'd wanted to ... but the pain has gone”). Pain: Whilst pain was important to almost all patients, it appeared to be less important than the other themes. Pain was predominately raised when it influenced other themes, such as function; many still felt the need to legitimize their foot pain in order for health professionals to take it seriously ("in the end I went to my GP because it had happened a few times and I went to an orthopaedic surgeon who was quite dismissive of it, it was like what are you complaining about”). Conclusions: Patients interpret the outcome of foot surgery using a multitude of interrelated factors, particularly functional ability, appearance and surgeons' appraisal of the procedure. While pain was often noted, this appeared less important than other factors in the overall outcome of the surgery. Future research into foot surgery should incorporate the complexity of how patients determine their outcome Disclosure statement: All authors have declared no conflicts of interes
Effects of the Distribution of Female Primates on the Number of Males
The spatiotemporal distribution of females is thought to drive variation in mating systems, and hence plays a central role in understanding animal behavior, ecology and evolution. Previous research has focused on investigating the links between female spatiotemporal distribution and the number of males in haplorhine primates. However, important questions remain concerning the importance of spatial cohesion, the generality of the pattern across haplorhine and strepsirrhine primates, and the consistency of previous findings given phylogenetic uncertainty. To address these issues, we examined how the spatiotemporal distribution of females influences the number of males in primate groups using an expanded comparative dataset and recent advances in Bayesian phylogenetic and statistical methods. Specifically, we investigated the effect of female distributional factors (female number, spatial cohesion, estrous synchrony, breeding season duration and breeding seasonality) on the number of males in primate groups. Using Bayesian approaches to control for uncertainty in phylogeny and the model of trait evolution, we found that the number of females exerted a strong influence on the number of males in primate groups. In a multiple regression model that controlled for female number, we found support for temporal effects, particularly involving female estrous synchrony: the number of males increases when females are more synchronously receptive. Similarly, the number of males increases in species with shorter birth seasons, suggesting that greater breeding seasonality makes defense of females more difficult for male primates. When comparing primate suborders, we found only weak evidence for differences in traits between haplorhines and strepsirrhines, and including suborder in the statistical models did not affect our conclusions or give compelling evidence for different effects in haplorhines and strepsirrhines. Collectively, these results demonstrate that male monopolization is driven primarily by the number of females in groups, and secondarily by synchrony of female reproduction within groups
Dynamics of magnetization at infinite temperature in a Heisenberg spin chain
Understanding universal aspects of quantum dynamics is an unresolved problem
in statistical mechanics. In particular, the spin dynamics of the 1D Heisenberg
model were conjectured to belong to the Kardar-Parisi-Zhang (KPZ) universality
class based on the scaling of the infinite-temperature spin-spin correlation
function. In a chain of 46 superconducting qubits, we study the probability
distribution, , of the magnetization transferred across the
chain's center. The first two moments of show superdiffusive
behavior, a hallmark of KPZ universality. However, the third and fourth moments
rule out the KPZ conjecture and allow for evaluating other theories. Our
results highlight the importance of studying higher moments in determining
dynamic universality classes and provide key insights into universal behavior
in quantum systems
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