Consequences Of Long-Term Fertilization on Wetland Microbial Function

Anthropogenic disturbances have led to increased deposition of nitrogen (N) and phosphorus (P) into soils. Nutrient enrichment of soils is known to increase plant biomass and also increase rates of microbial litter decomposition. Through decomposition, microorganisms release carbon (C) previously stored as organic C in soils into the atmosphere as carbon dioxide, a greenhouse gas. As these gaseous C emissions increase, global warming potential increases along with them. Understanding soil-microbe-plant interactions and their influence on decomposition rates is essential for understanding the causes of climate change and its mitigation. This study explores how shifts in organic C, N, and P caused by long-term nutrient enrichment and litter-type composition influence soil microbial function (e.g. decomposition). It is hypothesized that long-term nutrient enrichment causes shifts in soil microbial community structure that lead to higher rates of litter decomposition. Further, plant litter with a lower carbon C to N ratio (compared to high C:N ratio litter) is expected to decompose faster due to an available N source provided to nutrient-starved microbes. This study began at the long-term experimental fertilization and disturbance by mowing experiment at East Carolina University’s West Research Campus. In each of eight replicate mowed/fertilized and mowed/unfertilized plots, replicate bags of two different litter types (high C:N ratio rooibos tea and low C:N ratio green tea) were buried for 111 days. By using rooibos and green tea as a model plant litter with known C:N ratios, we are able to draw a link between litter type and decomposition rates by litter mass loss. Results revealed that soil microbes are capable of decomposing rooibos tea litter (higher C:N ratio) more quickly in fertilized compared to unfertilized. However, green tea litter (lower C:N ratio) decomposition rates were similar between fertilized and unfertilized plots. Overall, as predicted, the green tea litter decomposed faster than the rooibos tea litter. The outcomes of this study will provide insight into long-term effects of nutrient additions on soil microbial diversity and composition, related rates of decomposition, and the potential for climate change mitigation as nutrient enrichment continues to increase

SPATIO-TEMPORAL AND TIME DOMAIN KINETIC PARAMETER VARIABILITY CHANGES WITH AGE

Changes in kinematic parameters and variability in gait cycle duration with age have been associated with adaptations and/or degeneration of the human balance control system and the automated stepping mechanism. We postulated that the degeneration of the control system as related to age will be reflected in variability of selected parameters of the ground reaction force vector that are independent from the gait stride speed. To test this hypothesis we obtained quantitative measures of spatio-temporal parameters and ground reaction forces (GRF) of 45 healthy subjects 21-91 years of age. The variability in cadence and selected vertical and anteroposterior GRF parameters was found to increase significantly with age. These findings are discussed in terms of adaptations for safer gait in the elderly and/or degeneration due to aging

First Foods Nutrition Curriculum for New Immigrant Families: A Pilot Study

Background: Immigrant families arrive in the US from a variety of nutritional landscapes and educational experiences. Early childhood is a key time to intervene to set children on a healthy path. Creating nutritional education programs tailored for immigrant families may improve nutrition and health outcomes. Objective: To evaluate the First Foods curriculum as a tool for knowledge and behavior change for new immigrant families of young children. Methods: Immigrant caregivers of children less than 2 years old were invited to attend First Foods, a 4-class series. Each series was offered in 1 of 5 different languages (Arabic, Dari, Somali, Burmese, and Nepali). Recruitment occurred through community organizations, primary care clinics and Women, Infants, and Children (WIC), and classes were held in King County, Washington. The curriculum was developed and taught by a registered pediatric dietitian with input from general pediatricians, all experienced in the care of immigrant families. Classes were interpreted in the relevant language and course materials were translated. The classes were based on 4 themes -- 1) Child Eating and Development, 2) Eating Together, 3) Food Safety, and 4) Health Living -- and incorporated positive parenting and child development. Attendees completed pre- and post-surveys in their respective languages or in English. Descriptive statistics, chi-squared analyses, t-tests, and a multi-level linear regression model were conducted in Stata v14.0. Results: Participants in the classes included 47 caregivers (91% mothers). Nearly one-third had previously lived in a refugee camp. They had lived in the US a mean 5.5 years (95% CI: 3.8-7.2 years), attended a mean 8.6 years of school (95% CI: 7.1-10.1 years), and had a mean of 2.8 children (95% CI: 2.3-3.3 children). Classes ranged in size from 5 to 14 caregivers. Caregivers reported an improved understanding of 2 out of 4 methods to decrease risk of dental caries (drinking tap water, p = \u3c0.001; going to the dentist, p=0.02). They reported a decreased use of food as a reward from the pre- to the post-survey (p=0.027). Additionally, the caregivers reported increased frequency of considering sugar content in family foods (p=0.033), and decreased frequency of purchasing food at a convenience store, after participating in the curriculum (p=0.001). Conversely, there were several domains where caregivers did not show a change in their response. Conclusion: First Foods, a community-tailored, early childhood feeding curriculum for immigrant parents of young children, improved knowledge and behavior among caregivers from a variety of immigrant communities in some domains. In the other domains, there may be opportunities to further optimize the educational messages and approach

Similarities and Differences of the Soleus and Gastrocnemius H-reflexes during Varied Body Postures, Foot Positions, and Muscle Function: Multifactor Designs for Repeated Measures

<p>Abstract</p> <p>Background</p> <p>Although the soleus (Sol), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles differ in function, composition, and innervations, it is a common practice is to investigate them as single H-reflex recording. The purpose of this study was to compare H-reflex recordings between these three sections of the triceps surae muscle group of healthy participants while lying and standing during three different ankle positions.</p> <p>Methods</p> <p>The Sol, MG and LG muscles' H-reflexes were recorded from ten participants during prone lying and standing with the ankle in neutral, maximum dorsiflexion, and maximum plantarflexion positions. Four traces were averaged for each combination of conditions. Three-way ANOVAs (posture X ankle position X muscle) with planned comparisons were used for statistical comparisons.</p> <p>Results</p> <p>Although the H-reflex in the three muscle sections differed in latency and amplitude, its dependency on posture and ankle position was similar. The H-reflex amplitudes and maximum H-reflex to M-response (H/M) ratios were significantly 1) lower during standing compared to lying with the ankle in neutral, 2) greater during standing with the ankle in plantarflexion compared to neutral, and 3) less with the ankle in dorsiflexion compared to neutral during lying and standing for all muscles (<it>p </it>≤ .05).</p> <p>Conclusion</p> <p>Varying demands are required for muscles activated during distinctly different postures and ankle movement tasks.</p

Quadriceps force generation in patients with osteoarthritis of the knee and asymptomatic participants during patellar tendon reflex reactions: an exploratory cross-sectional study

BACKGROUND: It has been postulated that muscle contraction is slower in patients with osteoarthritis of the knee than asymptomatic individuals, a factor that could theoretically impair joint protection mechanisms. This study investigated whether patients with osteoarthritis of the knee took longer than asymptomatic participants to generate force during reflex quadriceps muscle contraction. This was an exploratory study to inform sample size for future studies. METHODS: An exploratory observational cross sectional study was carried out. Two subject groups were tested, asymptomatic participants (n = 17), mean (SD) 56.7 (8.6) years, and patients with osteoarthritis of the knee, diagnosed by an orthopaedic surgeon, (n = 16), age 65.9 (7.8) years. Patellar tendon reflex responses were elicited from participants and measured with a load cell. Force latency, contraction time, and force of the reflex response were determined from digitally stored data. The Mann-Whitney U test was used for the between group comparisons in these variables. Bland and Altman within-subject standard deviation values were calculated to evaluate the measurement error or precision of force latency and contraction time. RESULTS: No significant differences were found between the groups for force latency (p = 0.47), contraction time (p = 0.91), or force (p = 0.72). The two standard deviation measurement error values for force latency were 27.9 ms for asymptomatic participants and 16.4 ms for OA knee patients. For contraction time, these values were 29.3 ms for asymptomatic participants and 28.1 ms for OA knee patients. Post hoc calculations revealed that the study was adequately powered (80%) to detect a difference between the groups of 30 ms in force latency. However it was inadequately powered (59%) to detect this same difference in contraction time, and 28 participants would be required in each group to reach 80% power. CONCLUSION: Patients with osteoarthritis of the knee do not appear to have compromised temporal parameters or magnitude of force generation during patellar tendon reflex reactions when compared to a group of asymptomatic participants. However, these results suggest that larger studies are carried out to investigate this area further