Mass, nitrogen content, and decomposition of woody debris in forest stands affected by excreta deposited in nesting colonies of Great Cormorant

First online: 14 March 2015Great Cormorant (Phalacrocorax carbo), a piscivorous bird, has established breeding colonies in a coniferous forest near Lake Biwa in central Japan. This study investigated the possible effects of the colony’s excreta on the mass, nitrogen (N) content, and decomposition of woody debris. Study plots were established in forest stands representing four stages from breeding colony establishment to post-abandonment. The mass of fallen branches (diameter 1–5 cm) and coarse woody debris (logs, snags, and stumps; diameter ≥10 cm) was greater in forest stands colonized by Cormorants than a control stand never colonized by Cormorants. This was primarily attributed to Cormorant activity that caused increased mortality of standing trees and by Cormorants breaking branches for nesting materials. Nitrogen content of branches and logs that had fallen to the forest floor was negatively correlated with the relative density of wood. Nitrogen content of branches was consistently higher (at a given value of relative density) in the colonized stands than in the control stand. The increase of branch N content was possibly caused by the incorporation of N into decomposing branches with excreta-derived N supplied as throughfall and/or soil solution. The mean value of 2-year mass loss of recently dead branches and logs was significantly greater for woody debris in the smallest diameter class but was not significantly different among the forest stands. This suggests that the excessive supply of excreta-derived N and concomitant enrichment of N in soil had negligible effects on the initial stages of decomposition of woody debris

LATEST RESEARCHES ON RUNNING-SPECIFIC PROSTHESES: TOWARD SOCIAL IMPLEMENTATIONS OF BIOMECHANICS

Recent developments in running-specific prostheses (RSPs) have allowed individuals with lower extremity amputation (ILEAs) to regain the functional capability of running and jumping. However, the biomechanical characteristics of ILEAs using RSPs remain largely unknown. Understanding the biomechanical adaptations that occur during running and jumping with RSPs will assist clinicians and coaches in making objective decisions regarding the most appropriate prostheses, as well as in the fitting and alignment of these devices, for performance improvements in ILEAs. This presentation introduces our project regarding biomechanics of amputee athletes wearing RSPs, and its applications to athletes, prosthetists, manufacturers, and clinicians for the promotion of activity among amputees

COMPARISONS OF SPATIOTEMPORAL PARAMETERS OF 100-M SPRINT AMONG ELITE-, SUB-ELITE AND NON-ELITE AMPUTEE SPRINTERS

We investigated differences of the spatiotemporal parameters in a 100-m sprint among elite, sub-elite, and non-elite sprinters with a unilateral transtibial amputation. Using publicly available Internet broadcasts, we analyzed 125, 19, and 33 records from 30 elite, 12 sub-elite, and 22 non-elite sprinters, respectively. Average speed, step frequency, and step length were calculated Average speed was greatest in elite sprinters, followed by the sub-elite and non-elite groups. Although there was no significant differences in average step frequency, the average step length was longest in elite sprinters, followed by the sub-elite and non-elite groups. These results suggest that the differences in sprint performance between the three groups is mainly due to the average step length rather than step frequency

BRAKING AND PROPULSIVE IMPULSES ACROSS A RANGE OF RUNNING SPEEDS IN UNILATERAL TRANSFEMORAL AMPUTEES

Braking and propulsive ground reaction force impulses (GRIs) are mechanical parameters affecting the running performance. The purpose of this study was to determine the braking and propulsive GRIs across a range of speeds in unilateral transfemoral amputees. Ten unilateral transfemoral amputees ran on an instrumented treadmill at incremental speeds of 30%, 40%, 50%, 60%, and 70% of their maximum speed. At all given speeds, the braking GRI of affected limb was significantly smaller than unaffected limb; however, the propulsive GRIs were similar for both limbs. Consequently, the net anteroposterior GRI was positive in affected limb and negative in unaffected limb. These results suggest that the functional role of braking and propulsion is not the same between the limbs. Training for unilateral transfemoral amputees could focus on reducing the braking GRI of unaffected limb

LEG AND VERTICAL STIFFNESS OF TRANSFEMORAL AMPUTEES USING RUNNING-SPECIFIC PROSTHESES

Since running-specific prostheses (RSPs) emulate spring-like leg functions, human musculoskeletal system is often modelled as a spring-mass model. In the model, the leg (KM) and vertical stiffness (KM) is known to strongly influence running performance. The purpose of this study was to quantify the asymmetry in stiffness between the intact limbs and prosthetic limbs during sprinting. Eight sprinters with unilateral transfemoral amputation performed overground sprinting at maximum speed. & and Kw,t were calculated from vertical ground reaction force data in both the intact and prosthetic limbs. & was significantly greater in intact limbs than prosthetic limbs. Although there was no significant difference on Kvert, cohen's d of Kvert between legs was 1.28. Therefore KM might have potential significant difference

COMPARISON OF GROUND REACTION FORCES IN TWO RUNNING-SPECIFIC PROSTHESES (SPRINTER 1 E90 AND CHEETAH XTREME): A CASE STUDY

The purpose of this study was to describe the difference in ground reaction forces (GRF) between tvm different running-specific prostheses (RSPs) during maximal sprinting in a transfemoral amputee. One male sprinter performed maximal sprinting with two types of RSP (Sprinter 1E90 and Xtreme) on over 40 m runway with 7 force plates located halfway. Sprint velocity was found to be greater in the trials performed with Sprinter 1 E9O than with Xtreme. The peak VGRF, zero fore-aft shear and impulse of the anteriorposterior component of the GRF with PST limb differed among the two RSPs. These results suggest that the participant in this study would show the differences in variables influencing on the sprint velocity between two types of RSPs

JOINT MOMENTS OF UNILATERAL TRANSFEMORAL AMPUTEES USING RUNNING-SPECIFIC PROSTHESIS DURING SPRINTING

The aim of this study was to investigate the bilateral difference of the joint moments between an intact leg (INT) and a prosthetic leg (PST) in unilateral transfemoral amputees (TFAs) wearing running-specific prosthesis during sprinting. Eight sprinters with unilateral TFAs performed maximal sprinting on a 40-m runway with 7 force platforms located in between. Hip and knee joint extension and flexion moments during stance phase in INT were significantly greater than those of PST. However, ankle plantarflexion moment in PST was significantly greater than that of INT. Since kinetic asymmetry between legs is thought to be related with running-related injury, sprinter with unilateral TFAs may have a higher risk of musculoskeletal injury at hip and knee joints

Abundance, richness, and succession of microfungi in relation to chemical changes in Antarctic moss profiles

第6回極域科学シンポジウム[OB] 極域生物圏11月16日（月）　国立極地研究所１階交流アトリウ