We demonstrate a novel detection method for the cyclotron resonance frequency of an electron plasma in a Penning-Malmberg trap. With this technique, the electron plasma is used as an in situ ...diagnostic tool for the measurement of the static magnetic field and the microwave electric field in the trap. The cyclotron motion of the electron plasma is excited by microwave radiation and the temperature change of the plasma is measured non-destructively by monitoring the plasma's quadrupole mode frequency. The spatially resolved microwave electric field strength can be inferred from the plasma temperature change and the magnetic field is found through the cyclotron resonance frequency. These measurements were used extensively in the recently reported demonstration of resonant quantum interactions with antihydrogen.
Background
Maternal depression is associated with increased risk of psychiatric illness in offspring. While risk may relate to depressed mothers’ difficulties regulating emotions in the context of ...interacting with offspring, physiological indicators of emotion regulation have rarely been examined during mother–child interactions—and never among mother–adolescent dyads in which both mother and adolescent have histories of major depressive disorder (MDD).
Methods
We examined changes in high‐frequency heart rate variability (HF‐HRV), an indicator of parasympathetic (vagal) function that has been related to depression, stress, social engagement, and emotion regulation, in 46 mother–daughter dyads (23 in which both mother and daughter had an MDD history and 23 never‐depressed controls). Hierarchical linear models evaluated changes in HF‐HRV while mother–daughter dyads engaged in discussions about shared pleasant events and relationship conflicts.
Results
While control dyads displayed positive slopes (increases) in HF‐HRV during both discussions, MDD dyads displayed minimal change in HF‐HRV across discussions. Among controls, HF‐HRV slopes were positively correlated between mothers and daughters during the pleasant events’ discussion. In contrast, HF‐HRV slopes were negatively correlated between MDD mothers and daughters during both discussions.
Conclusions
Vagal responses observed in control mother–daughter dyads suggest a pattern of physiological synchrony and reciprocal positive social engagement, which may play a role in adolescent development of secure social attachments and healthy emotion regulation. In contrast, MDD mothers and daughters displayed diminished and discordant patterns of vagal responsiveness. More research is needed to understand the development and consequences of these patterns of parasympathetic responses among depressed mother–daughter dyads.
•Girls look more at live cues of positive evaluation than potentially critical cues.•Dysphoric girls look longer at live cues of potentially critical evaluation.•Dysphoria was not related to looking ...at live cues of positive evaluation.•Dysphoric girls looked more at potentially critical evaluation relative to positive.
Attention biases toward negative stimuli are implicated in the development and maintenance of depression. However, research is needed to understand how depression affects attention biases as they unfold in a dynamic social environment, particularly during adolescence when depression rates significantly increase due to enhanced reactivity to social stress. To examine attention biases in a live, socially evaluative environment, 26 adolescent girls from the community gave a speech in front of a potentially critical judge and a positive judge while wearing mobile eye tracking glasses. Girls' depressive symptoms were measured using the Moods and Feelings Questionnaire. Across the sample, girls looked at the positive judge more frequently and for longer periods of time compared with the potentially critical judge. In contrast, higher depressive symptoms were associated with looking at the potentially critical judge for longer periods of time. When directly comparing attention to the potentially critical judge relative to the positive judge, dysphoric girls looked at the potentially critical judge more frequently and for longer periods of time compared with the positive judge. Findings suggest that adolescent depressive symptoms are related to sustained attention toward potentially critical evaluation at the exclusion of positive evaluation. This novel approach allowed for an in vivo examination of attention biases as they unfold during social evaluation, which begins to illuminate the interpersonal significance of attention biases. If replicated and extended longitudinally, this research could be used to identify adolescents at high risk for future depression and potentially be leveraged clinically in attention bias modification treatment.
Parental socialization of emotion consists of parental behaviors that scaffold child emotional reactivity and regulation. The current study examined whether adolescents’ perceptions of their mothers’ ...supportive versus non‐supportive responses to negative emotions could predict adolescent emotional reactivity. Thirty adolescent girls (Mage = 14.41 1.55) reported on how their mothers typically respond to their negative emotions and then completed a laboratory‐based mother–adolescent interaction task. A multi‐modal assessment of adolescent emotional reactivity during the interaction included adolescents’ skin conductance levels (SCLs) and state anxiety, and mother–daughter interactions were behaviorally coded to assess how often dyads engaged in both negative and positive escalation (i.e., a pattern of negative or positive behavior of one partner being reciprocated by the other). Adolescents who reported that their mothers used more non‐supportive responses to their negative emotion tended to exhibit higher SCL and engage in more negative escalation with their mothers during the interaction task. Furthermore, adolescents’ SCL was positively correlated with both their state anxiety levels and negative escalation during the task. Together, these findings suggest that adolescents who perceive their mothers as less supportive of negative emotions are more likely to exhibit greater negative emotionality during parent–adolescent interaction, which may relate to risk for emotional disorders.
Antiretrovirals are a significant cost driver for HIV programmes. Current first-line regimens have performed well in real-life programmes, but have a low barrier to virological resistance and still ...carry toxicity that limits adherence. New drug developments may mean that we have access to safer, more robust and cheaper regimens, but only if the appropriate clinical trials are conducted. We briefly discuss these trials, and demonstrate the large cost savings to the South African HIV programme if these are successful.
Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly ...turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilate. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history.
The ALPHA collaboration has successfully demonstrated the production and the confinement of cold antihydrogen, H̅. An analysis of trapping data allowed a stringent limit to be placed on the electric ...charge of the simplest antiatom. Charge neutrality of matter is known to a very high precision, hence a neutrality limit of H̅ provides a test of CPT invariance. The experimental technique is based on the measurement of the deflection of putatively charged H̅ in an electric field. The tendency for trapped H̅ atoms to be displaced by electrostatic fields is measured and compared to the results of a detailed simulation of H̅ dynamics in the trap. An extensive survey of the systematic errors was performed, and this work focuses on those due to the silicon vertex detector, which is the device used to determine the H̅ annihilation position. The limit obtained on the charge of the H̅ atom is
Q
= (−1.3 ± 1.8 ± 0.4) × 10
−8
, representing the first precision measurement with H̅
1
.
Abstract Background Maternal depression is associated with negative outcomes for offspring, including increased incidence of child psychopathology. Quality of mother–child relationships can be ...compromised among affectively ill dyads, such as those characterized by maternal depression and child psychopathology, and negatively impact outcomes bidirectionally. Little is known about the neural mechanisms that may modulate depressed mothers' responses to their psychiatrically ill children during middle childhood and adolescence, partially because of a need for ecologically valid personally relevant fMRI tasks that might most effectively elicit these neural mechanisms. Methods The current project evaluated maternal response to child positive and negative affective video clips in 19 depressed mothers with psychiatrically ill offspring using a novel fMRI task. Results The task elicited activation in the ventral striatum when mothers viewed positive clips and insula when mothers viewed negative clips of their own (versus unfamiliar) children. Both types of clips elicited activation in regions associated with affect regulation and self-related and social processing. Greater lifetime number of depressive episodes, comorbid anxiety, and poor mother–child relationship quality all emerged as predictors of maternal response to child affect. Limitations Findings may be specific to dyads with psychiatrically ill children. Conclusions Altered neural response to child affect may be an important characteristic of chronic maternal depression and may impact mother–child relationships negatively. Existing interventions for depression may be improved by helping mothers respond to their children's affect more adaptively.
New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF3I and located in the SNOLAB underground laboratory. PICO-60 is the largest ...bubble chamber to search for dark matter to date. With an analyzed exposure of 92.8 livedays, PICO-60 exhibits the same excellent background rejection observed in smaller bubble chambers. Alpha decays in PICO-60 exhibit frequency-dependent acoustic calorimetry, similar but not identical to that reported recently in a C3F8 bubble chamber. PICO-60 also observes a large population of unknown background events, exhibiting acoustic, spatial, and timing behaviors inconsistent with those expected from a dark matter signal. These behaviors allow for analysis cuts to remove all background events while retaining 48.2% of the exposure. Stringent limits on weakly interacting massive particles interacting via spin-dependent proton and spin-independent processes are set, and most interpretations of the DAMA/LIBRA modulation signal as dark matter interacting with iodine nuclei are ruled out.
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