To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Experiencing poverty increases vulnerability for dysregulated hypothalamic–pituitary–adrenal (HPA) axis functioning and compromises long-term health. Positive parenting buffers children from HPA axis reactivity, yet this has primarily been documented among families not experiencing poverty. We tested the theorized power of positive parenting in 124 parent–child dyads recruited from Early Head Start (Mage = 25.21 months) by examining child cortisol trajectories using five samples collected across a standardized stress paradigm. Piecewise latent growth models revealed that positive parenting buffered children's stress responses when controlling for time of day, last stress task completed, and demographics. Positive parenting also interacted with income such that positive parenting was especially protective for cortisol reactivity in families experiencing greater poverty. Findings suggest that positive parenting behaviors are important for protecting children in families experiencing low income from heightened or prolonged physiologic stress reactivity to an acute stressor.
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
Deaths due to opioid overdose have reached unprecedented levels in Canada; over 12,800 opioid-related deaths occurred between January 2016 and March 2019, and overdose death rates increased by approximately 50% from 2016 to 2018.1 In 2016, Health Canada declared the opioid epidemic a national public health crisis,2 and life expectancy increases have halted in Canada for the first time in decades.3 Children are not exempt from this crisis, and the Chief Public Health Officer of Canada has recently prioritized the prevention of problematic substance use among Canadian youth.4
We present the results of a combined experimental and theoretical investigation of the stability of rings of millimetric droplets bouncing on the surface of a vibrating liquid bath. As the bath's vibrational acceleration is increased progressively, droplet rings are found to destabilize into a rich variety of dynamical states including steady rotational motion, periodic radial or azimuthal oscillations and azimuthal travelling waves. The instability observed is dependent on the ring's initial radius and drop number, and whether the drops are bouncing in- or out-of-phase relative to their neighbours. As the vibrational acceleration is further increased, more exotic dynamics emerges, including quasi-periodic motion and rearrangement into regular polygonal structures. Linear stability analysis and simulation of the rings based on the theoretical model of Couchman et al. (J. Fluid Mech., vol. 871, 2019, pp. 212–243) largely reproduce the observed behaviour. We demonstrate that the wave amplitude beneath each drop has a significant influence on the stability of the multi-droplet structures: the system seeks to minimize the mean wave amplitude beneath the drops at impact. Our work provides insight into the complex interactions and collective motions that arise in bouncing-droplet aggregates.
Organisms have been observing the behavior of other organisms for as long as there have been organisms. As humans, we are especially good at paying attention to cues from other humans and are acutely aware that people differ from each other. Astute observers of animal behavior have long noticed that individuals behave differently from one another, and a quick scan of popular YouTube channels devoted to individual pet cats strongly suggests that interest in the uniqueness of individual animals remains strong. What might be more surprising is that individual variation in nonhuman animals is no longer considered a mere curiosity in scientific circles: Over the past fifteen and more years individual variation in nonhuman animals (so called “animal personality”) has attracted the attention of animal behaviorists, who are now pursuing it as a serious research topic.
Recent work on political divisions in the mass public has identified several manifestations of polarization linked to different types of attitudes, orientations, and behaviors. Of these, affective polarization and perceived polarization have attracted increasing attention, though we still know fairly little of the links between these variants of polarization. In this paper, we examine the association between affective and perceived polarization, with an aim toward disentangling any potential causal relationship between the two processes. Using two sets of nationally representative panel data from 1992 to 1996 and 2008 to 2009, we find evidence that affective polarization causes perceived polarization, and that perceived polarization is not related to future affective polarization. Stratifying the models by level of political information, we find that the strength and statistical significance of the relationships between past and future values of affective and perceived polarization are conditional on political sophistication: more sophisticated individuals exhibit stronger relationships.
Reification – the act of treating something socially created as if it were real – is often described as a problem in the study of international norms. Critical and post-colonial scholars argue that reification silences alternative worldviews, whereas practice-oriented scholars argue it diminishes agency and practical innovation. In his article ‘From Norms to Normative Configurations,’ Simon Pratt proposes a solution to the problem of reification, reconceiving norms as a configuration of interrelated social practices. In this piece, I argue that the conventional wisdom is wrong. Reification is an essential part of how norms are constructed, contested, and surmounted in international politics. I revisit the foundational figures in norms research to highlight problems in Pratt's analysis, and prove the value of reification, both analytically and methodologically. Then, I use these insights to amend the concept of normative configuration, redefining it as a complex network of discrete norms tied together through common social practices. Along the way, I offer directions for future research on the relationship between norms and practices.
Germ plasm, a cytoplasmic factor of germline cell differentiation, is suggested to be a perspective tool for in vitro meiotic differentiation. To discriminate between the: (1) germ plasm-related structures (GPRS) involved in meiosis triggering; and (2) GPRS involved in the germ plasm storage phase, we investigated gametogenesis in the marine medaka Oryzias melastigma. The GPRS of the mitosis-to-meiosis period are similar in males and females. In both sexes, five events typically occur: (1) turning of the primary Vasa-positive germ plasm granules into the Vasa-positive intermitochondrial cement (IMC); (2) aggregation of some mitochondria by IMC followed by arising of mitochondrial clusters; (3) intramitochondrial localization of IMC-originated Vasa; followed by (4) mitochondrial cluster degradation; and (5) intranuclear localization of Vasa followed by this protein entering the nuclei (gonial cells) and synaptonemal complexes (zygotene–pachytene meiotic cells). In post-zygotene/pachytene gametogenesis, the GPRS are sex specific; the Vasa-positive chromatoid bodies are found during spermatogenesis, but oogenesis is characterized by secondary arising of Vasa-positive germ plasm granules followed by secondary formation and degradation of mitochondrial clusters. A complex type of germ plasm generation, ‘the follicle cell assigned germ plasm formation’, was found in late oogenesis. The mechanisms discovered are recommended to be taken into account for possible reconstruction of those under in vitro conditions.
Most research on the causes of women's underrepresentation examines one of two stages of the political pipeline: the development of nascent political ambition or specific aspects of the campaign and election process. In this article, we make a different kind of contribution. We build on the growing literature on gender, psychology, and representation to provide an analysis of what kinds of men and women make it through the political pipeline at each stage. This allows us to draw some conclusions about the ways in which the overall process is similar and different for women and men. Using surveys of the general U.S. population (N = 1,939) and elected municipal officials such as mayors and city councilors (N = 2,354) that measure the distribution of Big Five personality traits, we find that roughly the same types of men and women have nascent political ambition; there is just an intercept shift for sex. In contrast, male and female elected officials have different personality profiles. These differences do not reflect underlying distributions in the general population or the population of political aspirants. In short, our data suggest that socialization into political ambition is similar for men and women, but campaign and election processes are not.
We present the results of an integrated experimental and theoretical investigation of the vertical motion of millimetric droplets bouncing on a vibrating fluid bath. We characterize experimentally the dependence of the phase of impact and contact force between a drop and the bath on the drop’s size and the bath’s vibrational acceleration. This characterization guides the development of a new theoretical model for the coupling between a drop’s vertical and horizontal motion. Our model allows us to relax the assumption of constant impact phase made in models based on the time-averaged trajectory equation of Moláček and Bush (J. Fluid Mech., vol. 727, 2013b, pp. 612–647) and obtain a robust horizontal trajectory equation for a bouncing drop that accounts for modulations in the drop’s vertical dynamics as may arise when it interacts with boundaries or other drops. We demonstrate that such modulations have a critical influence on the stability and dynamics of interacting droplet pairs. As the bath’s vibrational acceleration is increased progressively, initially stationary pairs destabilize into a variety of dynamical states including rectilinear oscillations, circular orbits and side-by-side promenading motion. The theoretical predictions of our variable-impact-phase model rationalize our observations and underscore the critical importance of accounting for variability in the vertical motion when modelling droplet–droplet interactions.
Does President Trump face domestic costs for foreign policy inconsistency? Will co-partisans and opposition-partisans equally punish Donald Trump for issuing flippant international threats and backing down? While the president said he could “stand in the middle of Fifth Avenue and shoot somebody” without losing voters, the literature consistently shows that individuals, regardless of partisanship, disapprove of leaders who jeopardize the country’s reputation for credibility and resolve. Given the atypical nature of the Trump presidency, and the severe partisan polarization surrounding it, we investigate whether the logic of audience costs still applies in the Trump era. Using a unique experiment fielded during the 2016 presidential transition, we show that Republicans and Democrats impose equal audience costs on President Trump. And by varying the leader’s identity, between Donald Trump, Barack Obama, and “The President,” we demonstrate that the public adheres to a non-partisan logic in punishing leaders who renege on threats. Yet we also find Presidents Trump and Obama can reduce the magnitude of audience costs by justifying backing down as being “in America’s interest.” Even Democrats, despite their doubts of Donald Trump’s credibility, accept such justifications. Our findings encourage further exploration of partisan cues, leader-level attributes, and leader-level reputations.
OBJECTIVES/SPECIFIC AIMS: The objective of this project is to determine whether HRV, collected peri-operatively, is predictive of cognitive decline among older adults who undergo elective surgery/anesthesia. METHODS/STUDY POPULATION: This project is a part of the ongoing INTUIT/PRIME study, which is collecting pre- and post-operative cognitive testing, fMRI imaging, CSF samples, and EEG recordings from 200 older adults (age ≥ 60) undergoing elective non-cardiac/non-neurologic surgery scheduled to last > 2 hours at Duke University Medical Center and Duke Regional Hospital. This project utilizes data from the first 60 INTUIT participants who contributed continuous heart rate data before and during surgery. Participants undergo cognitive testing prior to surgery (baseline) and at 6 weeks after surgery. Our primary dependent variable is the change in the composite score from baseline to 6-weeks. Delirium is assessed in the hospital with the twice daily 3D-CAM tool, so we will report the proportion of individuals with 6-week cognitive decline who exhibited delirium in the days following surgery. Participants’ echocardiogram (ECG) recordings are extracted pre- and intraoperatively from B650/B850 patient monitors with VSCapture software. HRV is defined as the variability between successive R-spikes or inter-beat-intervals on ECG. RESULTS/ANTICIPATED RESULTS: We anticipate that lower intraoperative HRV is associated with worse cognitive decline at 6 weeks after surgery. As secondary objectives, we will determine whether pre-operative HRV or change in HRV (from pre-operative to intra-operative measures) are predictive of cognitive decline after surgery. We expect that in-hospital delirium will be detected in a higher proportion of those with 6-week cognitive decline, compared to those with stable or improved cognition at 6 weeks. DISCUSSION/SIGNIFICANCE OF IMPACT: HRV may address the present need for pre- and intra-operative cognitive risk stratification in the elderly. Physiological indices like HRV have the potential to dramatically change our understanding of CI in older adults undergoing surgery, as they offer an accessible, cost-effective, and non-invasive means whereby clinicians, particularly those unfamiliar with the nuances of geriatric and CI/dementia-related care, can monitor patients and refer those at high-risk of CI after surgery for early intervention.
n-3 Fatty acids are associated with better cardiovascular and cognitive health. However, the concentration of EPA, DPA and DHA in different plasma lipid pools differs and factors influencing this heterogeneity are poorly understood. Our aim was to evaluate the association of oily fish intake, sex, age, BMI and APOE genotype with concentrations of EPA, DPA and DHA in plasma phosphatidylcholine (PC), NEFA, cholesteryl esters (CE) and TAG. Healthy adults (148 male, 158 female, age 20–71 years) were recruited according to APOE genotype, sex and age. The fatty acid composition was determined by GC. Oily fish intake was positively associated with EPA in PC, CE and TAG, DPA in TAG, and DHA in all fractions (P≤0·008). There was a positive association between age and EPA in PC, CE and TAG, DPA in NEFA and CE, and DHA in PC and CE (P≤0·034). DPA was higher in TAG in males than females (P<0·001). There was a positive association between BMI and DPA and DHA in TAG (P<0·006 and 0·02, respectively). APOE genotype×sex interactions were observed: the APOE4 allele associated with higher EPA in males (P=0·002), and there was also evidence for higher DPA and DHA (P≤0·032). In conclusion, EPA, DPA and DHA in plasma lipids are associated with oily fish intake, sex, age, BMI and APOE genotype. Such insights may be used to better understand the link between plasma fatty acid profiles and dietary exposure and may influence intake recommendations across population subgroups.
We performed a spatial-temporal analysis to assess household risk factors for Ebola virus disease (Ebola) in a remote, severely-affected village. We defined a household as a family's shared living space and a case-household as a household with at least one resident who became a suspect, probable, or confirmed Ebola case from 1 August 2014 to 10 October 2014. We used Geographic Information System (GIS) software to calculate inter-household distances, performed space-time cluster analyses, and developed Generalized Estimating Equations (GEE). Village X consisted of 64 households; 42% of households became case-households over the observation period. Two significant space-time clusters occurred among households in the village; temporal effects outweighed spatial effects. GEE demonstrated that the odds of becoming a case-household increased by 4·0% for each additional person per household (P < 0·02) and 2·6% per day (P < 0·07). An increasing number of persons per household, and to a lesser extent, the passage of time after onset of the outbreak were risk factors for household Ebola acquisition, emphasizing the importance of prompt public health interventions that prioritize the most populated households. Using GIS with GEE can reveal complex spatial-temporal risk factors, which can inform prioritization of response activities in future outbreaks.
Following the approach of standard filtering theory, we analyse investor valuation of firms, when these are modelled as geometric-Brownian state processes that are privately and partially observed, at random (Poisson) times, by agents. Tasked with disclosing forecast values, agents are able purposefully to withhold their observations; explicit filtering formulae are derived for downgrading the valuations in the absence of disclosures. The analysis is conducted for both a solitary firm and m co-dependent firms.
We used the Pediatric Health Information System database to assess the use of antibiotics reserved for the treatment of resistant Gram-negative infections in children from 2004 to 2014. Overall, use of these agents increased in children from 2004 to 2007 and subsequently decreased.
Rapid changes in Helheim Glacier and other Greenland outlet glaciers since 2000 are well-known, but knowledge on earlier decades is fragmentary. Here we exploit the satellite image archives to produce and analyze a monthly-to-seasonal record of Helheim Glacier front position, 1980–2011. Statistical analysis identifies decadal periods with abrupt changes in variability and mean. The record also reveals evidence of volatile advance/retreat behavior in the 1980s. In one of several cases of large-amplitude subannual changes, the glacier front ‘surged’ forward in 1984/85, advancing ~6 km within a few months – surpassing its Little Ice Age maximum position – and afterward retreated ~5 km within a few weeks. These findings challenge the prevailing view of front position stability in the decades before the multi-year retreat in the early 2000s. Cold conditions including rigid ice mélange appear to be a factor in the high-amplitude seasonal advances in the 1980s. However the magnitude and abruptness of the changes in the record cannot be explained solely as a climatic response, such that glacio-dynamics must be invoked. Further, the volatile advance/retreat behavior in the cold 1980s resulted in increased dynamic ice loss, complicating the interpretation of increased calving activity as a response to warming.
To compare estimates from one day with usual intake estimates to evaluate how the adjustment for within-person variability affected nutrient intake and adequacy in Mexican children.
In order to obtain usual nutrient intakes, the National Cancer Institute’s method was used to correct the first 24 h dietary recall collected in the entire sample (n 2045) with a second 24 h recall collected in a sub-sample (n 178). We computed estimates of one-day and usual intakes of total energy, fat, Fe, Zn and Na.
2012 Mexican National Health and Nutrition Survey.
A total of 2045 children were included: 0–5·9 months old (n 182), 6–11·9 months old (n 228), 12–23·9 months old (n 537) and 24–47·9 months old (n 1098). From these, 178 provided an additional dietary recall.
Although we found small or no differences in energy intake (kJ/d and kcal/d) between one-day v. usual intake means, the prevalence of inadequate and excessive energy intake decreased somewhat when using measures of usual intake relative to one day. Mean fat intake (g/d) was not different between one-day and usual intake among children >6 months old, but the prevalence of inadequate and excessive fat intake was overestimated among toddlers and pre-schoolers when using one-day intake (P<0·05). Compared with usual intake, estimates from one day yielded overestimated prevalences of inadequate micronutrient intakes but underestimated prevalences of excessive intakes among children aged >6 months.
There was overall low variability in energy and fat intakes but higher for micronutrients. Because the usual intake distributions are narrower, the prevalence of inadequate/excessive intakes may be biased when estimating nutrient adequacy if one day of data is used.