The Tangled Web of Community Ecology: Making Sense of Complex Data

Ecological communities are governed by complicated processes that give rise to observable patterns. Making sense of these patterns, much less inferring the underlying processes, has proved challenging for several reasons. Manipulative experiments in natural communities may not be feasible due to large numbers of variables, lack of adequate replication, or the risk of undesirable consequences (e.g., introducing an invasive species). The multivariate nature of ecological datasets presents analytical problems as well; many statistical techniques familiar to ecologists have difficulty handling large numbers of potentially collinear variables. I present results from three studies of spider communities in which I employ a combination of familiar and less familiar statistical approaches to elucidate the factors influencing community structure in spiders. These approaches include null model analyses, nonmetric multidimensional scaling (NMS) for variable reduction of predictor and response data matrices, multiple regression, and observed variable structural equation modeling (SEM). While NMS has been employed as a multivariate descriptive analysis, examples of its use in further analyses are rare. SEM is a technique widely applied in other fields, but has only recently been used in ecological studies. General results from analyses of these three studies suggest that: 1) significant patterns of spider species co-occurrence based on null model analyses are consistent with a hypothesis of shared habitat preferences rather than one of species interactions, 2) in multiple regressions using NMS axes as predictor and response variables to compare the roles of plant species composition and habitat architecture in influencing spider species composition, the plants explained as much or more variation as the architecture, and 3) based on SEM analyses using NMS axes for spider species, plant species, arthropod orders and habitat architecture as variables, plant species composition acts both indirectly (through its effect on arthropods and architecture) and directly. The combination in these analyses of a traditionally descriptive multivariate approach (NMS) with null models, a classic regression approach, and SEM permits the analysis of otherwise statistically intractable datasets (the original data matrices). This suite of approaches provides new insights into spider community structure, and can be applied by ecologists working in other systems as well

The effects of plant species composition and habitat architecture on the organization of spider communities

Substantial empirical evidence in the ecological literature has demonstrated the importance of habitat structure in organizing animal communities. Species abundance and distributions have been shown to respond to a number of habitat structure parameters, including architectural complexity and structural heterogeneity (e.g.patchiness). Previous work in spider communities has indicated that spiders are no exception to this general pattern. Habitat structure is associated with spider species diversity, and different species within a community exhibit varying degrees of preference for specific habitat configurations. At the community level however, few, if any, studies have addressed the relationship between spider communities and plant species composition. This study assesses the relative influences of both habitat structure and plant species composition in three spider communities in East Tennessee. Data from the current study suggest that the species composition of the vegetation plays a prominent role in spider community organization. Results from Mantel tests indicate a stronger relationship between spider and plant species assemblages than between spider assemblages and habitat configurations. While species diversity and densities in these communities were significantly predicted by habitat structure, six of the twelve abundant species considered individually were significantly associated with plant species composition. Only three species were associated with habitat. The plant species may have reflected variations in habitat structure at a finer scale than that captured by the specific habitat measurements made in this study

An Intense and Short-Lasting Burst of Neutrophil Activation Differentiates Early Acute Myocardial Infarction from Systemic Inflammatory Syndromes

BACKGROUND: Neutrophils are involved in thrombus formation. We investigated whether specific features of neutrophil activation characterize patients with acute coronary syndromes (ACS) compared to stable angina and to systemic inflammatory diseases. METHODS AND FINDINGS: The myeloperoxidase (MPO) content of circulating neutrophils was determined by flow cytometry in 330 subjects: 69 consecutive patients with acute coronary syndromes (ACS), 69 with chronic stable angina (CSA), 50 with inflammation due to either non-infectious (acute bone fracture), infectious (sepsis) or autoimmune diseases (small and large vessel systemic vasculitis, rheumatoid arthritis). Four patients have also been studied before and after sterile acute injury of the myocardium (septal alcoholization). One hundred thirty-eight healthy donors were studied in parallel. Neutrophils with normal MPO content were 96% in controls, >92% in patients undergoing septal alcoholization, 91% in CSA patients, but only 35 and 30% in unstable angina and AMI (STEMI and NSTEMI) patients, compared to 80%, 75% and 2% of patients with giant cell arteritis, acute bone fracture and severe sepsis. In addition, in 32/33 STEMI and 9/21 NSTEMI patients respectively, 20% and 12% of neutrophils had complete MPO depletion during the first 4 hours after the onset of symptoms, a feature not observed in any other group of patients. MPO depletion was associated with platelet activation, indicated by P-selectin expression, activation and transactivation of leukocyte β2-integrins and formation of platelet neutrophil and -monocyte aggregates. The injection of activated platelets in mice produced transient, P-selectin dependent, complete MPO depletion in about 50% of neutrophils. CONCLUSIONS: ACS are characterized by intense neutrophil activation, like other systemic inflammatory syndromes. In the very early phase of acute myocardial infarction only a subpopulation of neutrophils is massively activated, possibly via platelet-P selectin interactions. This paroxysmal activation could contribute to occlusive thrombosis

Flowing Through Pain: Flow as a Tool to Manage Chronic Pain

Chronic pain perseveres for more than 3 months and affects various aspects of life, including but not limited to work, social relationships, and leisure. Though medication can treat the biological aspects of the chronic pain experience, it comes with side effects and rules set out by health insurance. Due to the various effects on life and limitations of medication, psychosocial treatments for chronic pain deserve more attention. Flow, being in the zone during an actively engaging and challenging experience may provide a respite from pain via decreased pain awareness. We assessed naturally occurring flow activities among the chronic pain population to explore whether being in a flow state is associated with a decrease in pain awareness and intensity (Study 1). Then we conducted an intervention study, where participants spent 15 minutes per day engaging in a flow activity or a mindfulness activity or went about life as usual. We aimed to delve deeper into the relationship between flow and chronic pain in relation to decreasing pain awareness and intensity and compare these effects to those of mindfulness, non-judgmental awareness and acceptance of present moment states, feelings, and sensations (Study 2). Across the two studies, results revealed that flow and mindfulness have similar effects on pain awareness suggesting that either type of activity can be engaged in with relatively equal decreases in pain awareness and intensity. We also learned that this sample of people with chronic pain chose to engage in flow and mindfulness activities that were active in nature, despite experiencing effects on life that were physical in nature as a result of their chronic pain. These results provide initial evidence in support of flow as a management strategy for chronic pain, such that a flow state can provide temporary respite from unrelenting pain

Self-compassion and empathy in caregiver and comparison groups: Differences in negative components

Self-compassion and empathy are positively associated with mental health, physical health, and well-being. Caregivers higher in self-compassion and empathy show increased caring and supportive behavior. Cultivating self-compassion and empathy have been suggested to enhance positive outcomes, however descriptive information about these constructs is lacking for caregiver and comparison groups. The current study examined self-compassion and empathy among caregivers (self-identified parents of at least one child under 18 years of age; n=335) and a comparison group (n=215). Caregivers had higher scores of total self-compassion and empathy, with lower scores of self-judgement, isolation, and overidentification (self-compassion subscales), and personal distress (empathy subscale). Describing self-compassion and empathy in caregiver and comparison groups has implications for key health outcomes and highlights differences in self- and other-directed constructs in a diverse sample of adults

Beyond an OSN Post: Looking at Emotional Valence and Request of Support/Information

Rheumatoid arthritis is a chronic autoimmune disease that does not have a cure. Therefore, it is important for patients to receive support, which would allow them to ask questions and express their feelings. This study examined online social networks for patients with rheumatoid arthritis to better understand the emotional valence of their initial posts and whether there was an association between posts with negative emotional valence and requesting support/information. We hypothesized that the majority (more than 50%) of the emotional valence of initial posts would be negative, and that there would be an association between negative emotional valence and support/information. Nine hundred eighty-six initial posts from a rheumatoid arthritis online social network via Reddit were coded as either positive, negative, neutral, or mixed. In addition, the initial posts were coded as either requesting support/information, offering support/information, neither requesting nor offering support/information, or both requesting and offering support/information. Negative was the most common emotional valence in the initial posts followed by mixed, neutral, and positive. There was also an association between initial posts that had a negative emotional valence and requested support/information, and initial posts that had a negative emotional valence but did not request support/information. As a result, the implications of this study indicate the need for additional information and support to be provided to patients with rheumatoid arthritis, so they can have a better experience and an easier way to cope with their illness

Chronic pain patients\u27 perspectives of medical cannabis.

Medical cannabis (MC) is used for a variety of conditions including chronic pain. The goal of this report was to provide an in-depth qualitative exploration of patient perspectives on the strengths and limitations of MC. Members of MC dispensaries (N = 984) in New England including two-thirds with a history of chronic pain completed an online survey. In response to How effective is medical cannabis in treating your symptoms or conditions?, with options of 0% no relief to 100% complete relief, the average was 74.6% ± 0.6. The average amount spent on MC each year was $3064.47 ± 117.60, median =$2320.23, range = $52.14 to$52,140.00. Open-ended responses were coded into themes and subthemes. Analysis of answers to What is it that you like most about MC? (N = 2592 responses) identified 10 themes, including health benefits (36.0% of responses, eg, Changes perception and experience of my chronic pain. ), the product (14.2%, eg, Knowing exactly what strain you are getting ), nonhealth benefits (14.1%), general considerations (10.3%), and medications (7.1%). Responses (N = 1678) to What is it that you like least about MC? identified 12 themes, including money (28.4%, eg, The cost is expensive for someone on a fixed income ), effects (21.7%, eg, The effects on my lungs ), the view of others (11.4%), access (8.2%), and method of administration (7.1%). These findings provide a patient-centered view on the advantages (eg, efficacy in pain treatment, reduced use of other medications) and disadvantages (eg, economic and stigma) of MC

Substitution of medical cannabis for pharmaceutical agents for pain, anxiety, and sleep.

A prior epidemiological study identified a reduction in opioid overdose deaths in US states that legalized medical cannabis (MC). One theory to explain this phenomenon is a potential substitution effect of MC for opioids. This study evaluated whether this substitution effect of MC for opioids also applies to other psychoactive medications. New England dispensary members ( n = 1,513) completed an online survey about their medical history and MC experiences. Among respondents that regularly used opioids, over three-quarters (76.7%) indicated that they reduced their use since they started MC. This was significantly ( p \u3c 0.0001) greater than the patients that reduced their use of antidepressants (37.6%) or alcohol (42.0%). Approximately two-thirds of patients decreased their use of anti-anxiety (71.8%), migraine (66.7%), and sleep (65.2%) medications following MC which significantly ( p \u3c 0.0001) exceeded the reduction in antidepressants or alcohol use. The patient\u27s spouse, family, and other friends were more likely to know about their MC use than was their primary care provider. In conclusion, a majority of patients reported using less opioids as well as fewer medications to treat anxiety, migraines, and sleep after initiating MC. A smaller portion used less antidepressants or alcohol. Additional research is needed to corroborate these self-reported, retrospective, cross-sectional findings using other data sources