141 research outputs found

    The Effects of Social Media on Psychological Distress: Contributions of Loneliness, Fear of Missing Out, and Need Satisfaction

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    Social media use is a major part of everyday American life and has continued to increase in the last decade particularly due to increased access of social media capable devices. The most frequent users of social media appear to be adolescent youth and college aged adults. Being as pervasive as it is, the effects of social media use as worth exploring. Research has established associations between social media use and negative mental and physical health outcomes. A key area of study has explored loneliness and found social media use predicts increased feelings of loneliness. Other research contests these findings suggesting other factors beyond just usage, and some argue that social media use can even reduce loneliness. These conflicting findings suggest the potential role of motivation and intention for engaging in social media use. Such drivers of social media use may be found within self-determination theory, and fear of missing out. The study evaluated a moderated mediation model wherein the indirect effect of social media use on distress were mediated by loneliness, the latter of which was moderated by need satisfaction and FOMO. The results indicate that social media does not exhibit a moderated mediation effect. There was no evidence that need satisfaction and FOMO moderated the effect of social media usage on loneliness, which in turn was hypothesized to be linked to heightened psychological distress. Social media use was also not associated with higher levels of distress, nor did it predict loneliness when moderated by FOMO or needs satisfaction. Finally, loneliness was positively associated with distress

    Flexible desk top computers using Large Scale Integration (L.S.I.) chips

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    Microprogrammable modular computer utilizing only seven different types of L.S.I. elements lowers manufacturing cost and improves reliability. Chips can be standarized and used to implement variable bit length computers

    The Effect of Monetary Policy on Economic Output

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    There is substantial research effort devoted to identifying a sufficient statistic for monetary policy. The purpose of this paper is to broaden the scope of the on-going investigation along three dimensions. First, we follow up the Rudebusch-Svensson claim of parameter instability in the output regressions by examining the statistical stability of the parameter estimates with post-1996 data. Second, we examine whether alternative measures of the cyclical component affect the correlation between money supply, interest rates and output. Third, we consider alternative measures of the money supply, permitting us to assess the distinct roles of inside and outside money in terms of the correlation between each component and output

    Echo in Optical Lattices: Stimulated Revival of Breathing Oscillations

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    We analyze a stimulated revival (echo) effect for the breathing modes of the atomic oscillations in optical lattices. The effect arises from the dephasing due to the weak anharmonicity being partly reversed in time by means of additional parametric excitation of the optical lattice. The shape of the echo response is obtained by numerically simulating the equation of motion for the atoms with subsequent averaging over the thermal initial conditions. A qualitative analysis of the phenomenon shows that the suggested echo mechanism combines the features of both spin and phonon echoes.Comment: 13 pages, 3 figure

    Assessing carbon stocks and accumulation potential of mature forests and larger trees in U.S. federal lands

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    Mature and old-growth forests (collectively “mature”) and larger trees are important carbon sinks that are declining worldwide. Information on the carbon value of mature forests and larger trees in the United States has policy relevance for complying with President Joe Biden’s Executive Order 14072 directing federal agencies to define and conduct an inventory of them for conservation purposes. Specific metrics related to maturity can help land managers define and maintain present and future carbon stocks at the tree and forest stand level, while making an important contribution to the nation’s goal of net-zero greenhouse gas emissions by 2050. We present a systematic method to define and assess the status of mature forests and larger trees on federal lands in the United States that if protected from logging could maintain substantial carbon stocks and accumulation potential, along with myriad climate and ecological co-benefits. We based the onset of forest maturity on the age at which a forest stand achieves peak net primary productivity. We based our definition of larger trees on the median tree diameter associated with the tree age that defines the beginning of stand maturity to provide a practical way for managers to identify larger trees that could be protected in different forest ecosystems. The average age of peak net primary productivity ranged from 35 to 75 years, with some specific forest types extending this range. Typical diameter thresholds that separate smaller from larger trees ranged from 4 to 18 inches (10–46 cm) among individual forest types, with larger diameter thresholds found in the Western forests. In assessing these maturity metrics, we found that the unprotected carbon stock in larger trees in mature stands ranged from 36 to 68% of the total carbon in all trees in a representative selection of 11 National Forests. The unprotected annual carbon accumulation in live above-ground biomass of larger trees in mature stands ranged from 12 to 60% of the total accumulation in all trees. The potential impact of avoiding emissions from harvesting large trees in mature forests is thus significant and would require a policy shift to include protection of carbon stocks and future carbon accumulation as an additional land management objective on federal forest lands

    Direct Determination of Fission-Barrier Heights Using Light-Ion Transfer in Inverse Kinematics

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    We demonstrate a new technique for obtaining fission data for nuclei away from β\beta-stability. These types of data are pertinent to the astrophysical \textit{r-}process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of 239^{239}U has been determined via the 238^{238}U(dd,pfpf) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique

    The Impact of Sub-maximal Exercise on Neuropathic Pain, Inflammation, and Affect Among Adults With Spinal Cord Injury: A Pilot Study

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    Introduction: Persons with spinal cord injury (SCI) often report high levels of neuropathic pain (NP) and poor well-being, which may result from increased inflammation. This study examined the impact of sub-maximal aerobic exercise on NP, inflammation and psychological affect among adults with SCI. Methods: Eight active adults with tetraplegia (n-4, AIS A-C) and paraplegia (n = 4, AIS A-C) performed 30-min of arm-crank aerobic exercise and reported their ratings of perceived exertion (RPE) each minute. Measures of NP, affect, and inflammatory cytokines (IL-6, IL-10, IL-1ra, TNF-α) were taken pre-(T0), immediately post-(T1), and 90-min post-exercise (T2). Results: NP decreased between T0 and T1 for tetraplegics (−60%, d = 0.47; CI = −0.32, 2.02) and paraplegics (−16%, d = 0.15; CI = −0.30, 0.90). Correlations between change in cytokines and change in NP were medium-to large for tetraplegics (rs ranged from −0.820 to 0.965) and paraplegics (rs ranged from −0.598 to 0.833). However, the pattern of correlations between change in cytokines and affect was inconsistent between groups. Lower baseline levels of IL-1ra predicted greater decreases in NP immediately post-exercise (r = 0.83, p = 0.01). Conclusion: Sub-maximal exercise can positively impact NP for some persons with SCI. Further experimental research should identify the optimal exercise intensity to reduce NP for persons with SCI, in addition to understanding biomarkers which may predict changes in NP. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03955523

    Acute submaximal exercise does not impact aspects of cognition and BDNF in people with spinal cord injury: A pilot study

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    ObjectiveTo investigate the effect of acute submaximal exercise, based on the spinal cord injury (SCI) Exercise Guidelines, on cognition and brain-derived neurotrophic factor (BDNF) in people with SCI.DesignEight adults (7 males) with traumatic SCI volunteered in this pre-registered pilot study. In randomized order, participants completed submaximal intensity arm cycling (60% of measured peak-power output at 55–60 rpm) for 30 min or time-matched quiet rest (control condition) on separate days. Blood-borne BDNF was measured in serum and plasma at pre-intervention, 0 min and 90 min post-intervention. Cognition was assessed using the Stroop Test and Task-Switching Test on an electronic tablet pre- and 10 min post-intervention.ResultsSubmaximal exercise had no effect on plasma [F(2,12) = 1.09; P = 0.365; η² = 0.069] or serum BDNF [F(2,12) = 0.507; P = 0.614; η² = 0.024] at either 0 min or 90 min post-intervention. Similarly, there was no impact of exercise on either Stroop [F(1,7) = 2.05; P = 0.195; η² = 0.065] or Task-Switching performance [F(1,7) = 0.016; P = 0.903; η² < 0.001] compared to the control condition. Interestingly, there was a positive correlation between years since injury and resting levels of both plasma (r = 0.831; P = 0.011) and serum BDNF (r = 0.799; P = 0.023). However, there was not relationship between years since injury and the BDNF response to exercise.ConclusionsAcute guideline-based exercise did not increase BDNF or improve aspects of cognition in persons with SCI. This work establishes a foundation for continued investigations of exercise as a therapeutic approach to promoting brain health among persons with SCI

    CATMoS: Collaborative Acute Toxicity Modeling Suite.

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    BACKGROUND: Humans are exposed to tens of thousands of chemical substances that need to be assessed for their potential toxicity. Acute systemic toxicity testing serves as the basis for regulatory hazard classification, labeling, and risk management. However, it is cost- and time-prohibitive to evaluate all new and existing chemicals using traditional rodent acute toxicity tests. In silico models built using existing data facilitate rapid acute toxicity predictions without using animals. OBJECTIVES: The U.S. Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) Acute Toxicity Workgroup organized an international collaboration to develop in silico models for predicting acute oral toxicity based on five different end points: Lethal Dose 50 (LD50 value, U.S. Environmental Protection Agency hazard (four) categories, Globally Harmonized System for Classification and Labeling hazard (five) categories, very toxic chemicals [LD50 (LD50≤50mg/kg)], and nontoxic chemicals (LD50>2,000mg/kg). METHODS: An acute oral toxicity data inventory for 11,992 chemicals was compiled, split into training and evaluation sets, and made available to 35 participating international research groups that submitted a total of 139 predictive models. Predictions that fell within the applicability domains of the submitted models were evaluated using external validation sets. These were then combined into consensus models to leverage strengths of individual approaches. RESULTS: The resulting consensus predictions, which leverage the collective strengths of each individual model, form the Collaborative Acute Toxicity Modeling Suite (CATMoS). CATMoS demonstrated high performance in terms of accuracy and robustness when compared with in vivo results. DISCUSSION: CATMoS is being evaluated by regulatory agencies for its utility and applicability as a potential replacement for in vivo rat acute oral toxicity studies. CATMoS predictions for more than 800,000 chemicals have been made available via the National Toxicology Program's Integrated Chemical Environment tools and data sets (ice.ntp.niehs.nih.gov). The models are also implemented in a free, standalone, open-source tool, OPERA, which allows predictions of new and untested chemicals to be made. https://doi.org/10.1289/EHP8495
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