680 research outputs found
The Neuroinflammatory Effects of Chronic Unpredictable Stress on Zebrafish, Danio rerio
Stress is a state of threatened homeostasis counteracted by various physiologic and behavioral responses aimed to maintain or restore balance. As such, stress acts as a motivator to perform during the challenges of life to survive. Chronic perturbations to the stress response homeostasis without relief can lead to dysregulation, thus attenuating organ systems and structures and causing significant damage {1]. Individuals who undergo psychological trauma endure an acute and transient experience, which results in minimal functional impairment, but some suffer from a chronic condition called posttraumatic stress disorder (PTSD). Individuals who have PTSD are likely to experience intense stress, fear, anxiety, and helplessness, resulting in a permanent or temporary psychological wound characterized by physical, cognitive, emotional, or behavioral changes. In this study, we will be exploring the physiologic and behavioral effects of chronic stress on functionally distinct brain areas related to reward and aversion, the neuromodulator dopamine (DA), and DA’s critical role in mediating behaviors used to meet survival needs.
In this study, we used the zebrafish to model PSTD by implementing a chronic unpredictable stress paradigm to simulate a traumatic experience. We measured behavior differences using an anxiety-like behavior assay, the Light-Dark Preference Test, and attempted to validate our findings using immunohistochemistry and microscopy to observe brain changes in regions of interest involving aversion. Though experimental zebrafish did respond to stressful stimuli, exhibiting typical anxiety-like behaviors, there was no significant difference amongst our groups. Multiple behaviors were present but unquantifiable due to experimental error. Additionally, we found there to be no significant difference in the effect of PTSD on the brain. However, post ad-hoc tests indicated individual differences amongst experimental groups for the average time in the light compartment statistic, the number of crosses into the light compartment statistic, and the single pairwise difference in tyrosine hydroxylase (TH) expression, suggesting that stress still may induce anxiety behaviors and affect the neurocircuits that modulate stress. These outliers prompt additional trials with larger sample sizes
A Comparison of Sexual Minority Youth Who Attend Religiously-Affiliated Schools and Their Nonreligious School-Attending Counterparts
Sexual minority (lesbian, gay, and bisexual) youth are an at-risk group for negative health outcomes; however, investigations into potential protective factors, such as religion, are rarely conducted. Investigations of sexual minority youth who attend schools with religious affiliation, and how attending a religiously-affiliated school may relate to alcohol use and school belonging in this at-risk population, are lacking in the literature. The present study compares descriptive characteristics and “outness” levels of sexual minority youth who attend religious schools to sexual minorities who do not attend religious schools (Objective one), and also investigates if attending religiously-affiliated schools is associated with levels of alcohol use and school belonging among sexual minority youth (Objective two). A sample of 475 sexual minority high school students completed an online survey assessing demographics, high school climate, alcohol use (Alcohol Use Disorders Identification Test, or AUDIT), and school belonging. Participants were matched to a comparison sample to compare AUDIT and school belonging scores. The differences in “outness” between groups were tested using chi-square analysis, and after matching participants, two independent samples t tests were conducted on AUDIT scores and School Belonging scores.
Sexual minorities attending religiously-affiliated schools had significantly higher AUDIT scores and decreased high school “outness” levels than their nonreligious school-attending counterparts, but attendance at a religiously-affiliated school had no significant association with school belonging. According to the minority stress hypothesis by Meyer (2003) concealment of sexual orientation can lead to increased stress, which can result in increased alcohol use. This hypothesis may help to explain the elevated co-occurring levels of alcohol use and concealment. If sexual minority youth who attend religiously-affiliated schools are facing increased minority stress above and beyond the health disparities already present within this at-risk population, then future research is needed in this area to document the risks involved with attendance at such schools as a sexual minority
The Effect of pH and Pulsed Ultraviolet Light Emitting Diode Duty Cycles on the First Order Rate Constant and Byproduct Profile of the Advanced Oxidation of Tartrazine
Water treatment capability is required for military operations, production of drinking water, and industrial wastewater treatment. The Advanced Oxidation Process (AOP) is one of many viable steps for treating water; however, it is important to understand the byproducts of the treatment process to avoid creating other constituents more severe than the first. Tartrazine (TAR) was oxidized with pulsed Ultra- Violet (UV) Light Emitting Diodes (LEDs) in combination with hydrogen peroxide (H2O2) in an AOP at the laboratory scale. The relative concentration of TAR was reduced from 1 to between 1 – 0.75 over pH values between 6 and 9, and at Duty Cycles (DCs) ranging from 0% to100%. The first order rate constant for TAR removal was statistically and positively correlated with DC, was statistically and negatively correlated with pH, and was typically greatest at pH6. DC and pH were variables in a regression model of the first order rate constant with adjusted R2 of 0.85. Chromatographic contrast angle determinations revealed that the byproduct profile was most significantly influenced by pH 7 under both positive and negative ionization, by the 70% DC for the positive ionization, and 50% DC for the negative ionization. DC and pH were variables in regression models
DISENTANGLING THE RELATIONS BETWEEN ACUTE STRESS, CHRONIC STRESS, AND PROSPECTIVE MEMORY
Given the importance and prevalence of Prospective Memory (PM) in daily life and the common experience of stress, it is critical to understand the relations between them. Despite a growing literature base, the answers to some of the simplest questions about these relations remain unanswered. The present study was designed to investigate the relations between both acute and chronic stress and time- and event-based PM. Several methodological features make this study unique and may contribute to a broadening of our understanding of PM in daily life. The results of the present study revealed that chronic stress was negatively correlated with strategic clock monitoring and time-based PM. On the other hand, chronic stress measures did not correlate significantly with either focal or non-focal event-based PM. Acute stress was not correlated with significant differences in PM performance. Prospective memory performance was not significantly correlated with time of day, nor did time of day help to account for the general null findings between acute stress and PM abilities. Continuing to explore the nuanced ways in which stress and PM interact will clarify whether different types of stress can be beneficial or detrimental to one’s ability to complete intentions in the future, and under what conditions
High pressure structural studies on Nb5Si3 up to 26.2 GPa
With the use of synchrotron techniques, we can better understand how crystalline structures behave under extreme conditions. This yields the opportunity to resolve complex crystal structures [1]. Here, we focus on the high pressure crystal structure of Nb5Si3. Refractory metal silicides are an important class of materials as they are used in high temperature applications such as turbines and aerospace modules. As an example, the performance of a jet engine is highly influenced by the maximum internal pressure and temperature possible. Obtaining higher levels of thrust is dependent upon the material\u27s ability to remain structurally sound under extreme temperatures and pressures; Nb5Si3 has a higher melting temperature and lower density achieving better performance under said conditions [2]
The Quantitative Turn in Transitional Justice Research: What Have We Learned About Impact?
In recent years, scholars have increasingly turned to quantitative research methods to understand the impact of transitional justice (TJ) on societies emerging from periods of violence and repression. This research often seeks to influence policy diffusion by making bold claims based upon large datasets of TJ events that span space and time. However, the policy advice from the first wave of quantitative research is inconsistent if not contradictory. In this article, we outline a range of methodological issues that help to explain the different conclusions reached by these studies, including sampling strategies, model construction, and the measurement of key variables. Furthermore, these studies have often failed to provide compelling theoretical or empirical bases for a causal relationship between TJ mechanisms and dependent variables such as democracy and human rights. We suggest several ways in which quantitative scholars could produce findings with broader credibility. Although we support the use of quantitative methods to understand the impact of TJ mechanisms, greater methodological care is needed in supporting policy recommendations
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Choosing Your Neighbors: Networks of Diffusion in International Relations
In examining the discussion of social and political phenomena like regime transition, conflict, and policy change, scholars routinely make choices about how proximity is defined and which neighbors should be considered more important than others. Since each specification offers an alternative view of the networks through which discussion can take place, one's decision can exert a significant influence on the magnitude and scope of estimated discussion effects. This problem is widely recognized, but is rarely the subject of direct analysis. In international relations research, connectivity choices are usually ad hoc, driven more by data availability than by theoretically informed decision criteria. We take a closer look at the assumptions behind these choices, and propose a more systematic method to asses the structural similarity of two or more alternative networks, and select one that most plausibly relates theory to empirics. We apply this method to the spread of democratic regime change, and offer an illustrative example of how neighbor choices might impact predictions and inferences in the case of the 2011 Arab Spring.GovernmentSociolog
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