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1.
Subterranean termites excavate complex underground tunnels for foraging. Most tunnels comprise primary and secondary tunnels. Tunnels originating from the nest are called primary and those branching from the primary tunnels are named secondary tunnels; tertiary and quaternary tunnels are rarely observed. During foraging, termites may thus encounter a considerable number of tunnel-branching nodes. Directional selection at such a node is likely correlated to tunnel-growth activity because tunnels containing more termites have a higher probability of growth. In this study, we investigated how termites select the direction of movement at an artificially-designed branching node, by making chemical trails on filter paper, drawing lines using a ballpoint pen which contained the chemical substance that induces the termite to follow trails. The trails consisted of two lines: straight and branching. The branching line was drawn from the center of the straight line at an angle θ (10°, 20°,…, 90°). We then calculated the ratio of the directional selection as r = Ns/Nb, where Ns and Nb represent the number of straight and branching tunnels selected, respectively. The values of r were statistically classified into three groups based on the angle of the branching trail, as follows: 10°  θ  20°, 30°  θ  60°, and 70°  θ  90°. Our paper briefly discusses the underlying mechanisms of the experimental results.  相似文献   

2.
The asymmetrical weight-bearing distribution of individuals with hemiparesis rising from a chair might be used to produce similar muscular efforts at the lower limbs. The aim of this study was to determine if individuals with hemiparesis have symmetrical levels of effort at the knee during spontaneous sit-to-stand transfers. Nineteen subjects with hemiparesis and 16 healthy controls participated. Their weight-bearing (WB) distribution during sit-to-stand was assessed with a force platform setup while the knee effort distribution was quantified using electromyographic (EMG) data normalized to maximal EMG values then expressed relative to the sum of the bilateral efforts. The healthy individuals presented symmetrical weight-bearing and knee effort distributions during the sit-to-stand transfer. The participants with hemiparesis, classified in three subgroups based on knee extensors’ strength asymmetries (mild, moderate and severe), yielded different results. The mild group (n = 6) behaved like the controls, with almost symmetrical WB and knee efforts. The moderate group (n = 7) had similar WB and effort asymmetries while the severe group (n = 6) exhibited a WB distribution difference between sides but had almost symmetrical knee effort. These results for the severe group suggest that a control is exerted on the levels of effort when rising from a chair, which might be required when a certain threshold of effort is reached on the nonparetic side.  相似文献   

3.
Disruptions to an ecological system can have profound effects on the use of that system by various species. Such effects are often studied in terrestrial or aquatic species, but subterranean species are equally affected. To investigate how environmental perturbation affects the territory size of subterranean termites, a lattice model was designed based using seasonal and behavioral data to simulate the foraging behavior of the Formosan subterranean termite Coptotermes formosanus Shiraki. This computer model was then used to subject a given number of founding pairs (N = 20, 40, 60, 80, 100 at t = 0) to several levels of environmental perturbations (H = 0.0–1.0) once initial territory growth had reached saturation for a fixed area (t = 5). At lower values of H, territories were reduced to localized holdings randomly distributed over the entire model area. As H increased, the size of surviving territories increased while the total number of territories decreased. Analysis of territory size post-disruption (t = 10) indicated a trend towards larger overall territorial size when both N and H were high, whereas no such increase was seen when N was low. These results can be used to improve modeling systems to determine survival of subterranean populations in environmental disasters.  相似文献   

4.
The aim of this study was to determine the effects of anterior cruciate ligament reconstruction (ACLR) on sub-maximal quadriceps force control with respect to quadriceps and hamstring muscle activity. Thirty ACLR individuals together with 30 healthy individuals participated. With real-time visual feedback of muscle force output and electromyographic electrodes attached to the quadriceps and hamstring muscles, subjects performed an isometric knee extension task where they increased and decreased their muscle force output at 0.128 Hz within a range of 5–30% maximum voluntary capacity. The ACLR group completed the task with more error and increased medial hamstring and vastus medialis activation (p < 0.05). Moderate negative correlations (p < 0.05) were observed between quadriceps force control and medial (Spearman’s rho = −0.448, p = 0.022) and lateral (Spearman’s rho = −0.401, p = 0.034) hamstring activation in the ACLR group. Diminished quadriceps sub-maximal force control in ACLR subjects was reflective of medial quadriceps and hamstring dyskinesia (i.e., altered muscle activity patterns and coordination deficits). Within the ACLR group however, augmented hamstring co-activation was associated with better quadriceps force control. Future studies should explore the convergent validity of quadriceps force control in ACLR patients.  相似文献   

5.
The polymorphism of the mitochondrial gene cytochrome oxidase III was studied in the Mediterranean octopus, Octopus vulgaris Cuvier, 1797. A total of 202 specimens from seven sampling sites were analysed with the aim of elucidating patterns of genetic structure in the central Mediterranean Sea and to give an insight into the phylogeny of the Octopus genus. Phylogenetic analyses showed that individuals from the central Mediterranean belong to the O. vulgaris species whose limits should nevertheless be clarified. Concerning genetic structure, two high-frequency haplotypes were present in all locations. The overall genetic divergence (ΦST = 0.05, P < 0.05) indicated a significant genetic structuring in the study area and an AMOVA highlighted a significant break between western and eastern Mediterranean basins (ΦCT = 0.094, P < 0.05). Possible explanations for the observed patterns of genetic structuring are discussed with reference to their relevance for fisheries management.  相似文献   

6.
This study focused on understanding the termite traveling behavior. Artificial tunnels with different curvatures and base surface roughness were constructed. Each tunnel was 50 mm in length, with widths of W (W = 2, 3, or 4 mm). The distance between the two ends of the tunnel was D (D = 20, 30, 40, or 50 mm). A higher value of D means a lower curvature. The roughness, R (R = 60, 120, 240 and ∞), was generated by uniformly sanding the substrate with a sanding machine. A higher R value means a finer base surface. The symbol ∞ represents a smooth surface. Time (τ) taken by a termite to pass through the tunnel was measured. τ was longer in tunnels with a smooth surface compared with the tunnels with a rough surface. When W = 2, there was no effect of the roughness on speed. This is because the narrow tunnel width diluted the effects of the smoothness of the surface. When W = 3, τ was statistically shorter for R = 240, than for R = 60 and 120. This suggests that an appropriate surface roughness could positively contribute to the traveling speed.  相似文献   

7.
The Ansell's mole-rat (Fukomys anselli, Bathyergidae) is a small-sized social subterranean rodent whose distribution is confined to the Lusaka area in Zambia. It is an established model species for various laboratory studies, but until now the knowledge of its biology under natural conditions has been limited. Here, we provide the first comprehensive natural history and ecological data on a free living population from Miombo woodland. The Ansell's mole-rat lives in groups of up to 13 individuals (mean 9.7 ± 2.5; N = 9 complete, fully established family groups) with a single breeding pair per group. The family groups occupy very large and complex burrow systems consisting of 0.5–2.8 km of tunnels (mean = 1.2 ± 0.6 km, N = 15), which are densely branched and reticulated especially around nests. Burrow systems of neighbouring family groups were often interconnected by a freely passable tunnel, which has never before been documented in any African mole-rats. Mole-rat food density in the study area was relatively low (10.0 ± 8.4 m?2) but its biomass was large (457 ± 889 g m?2). This, together with a relatively workable soil (cone resistance = 529 ± 26 N cm?2 at the end of June, with 10% soil humidity), indicates moderate ecological conditions, which disagrees with the aridity food-distribution hypothesis (AFDH) considering small body size and sociality in bathyergids adaptations to harsh environments.  相似文献   

8.
Evidence indicates that previous low back injury (LBI) is a strong predictor for re-injury. The purpose of this study was to examine whether neuromuscular patterns remain altered in a LBI group who were deemed recovered. Surface electromyograms from 12-abdominal and 12-back extensors sites and motion variables were recorded from 33 LBI individuals (sub-acute phase) and 54 asymptomatic controls. Pain-related variables were recorded and a clinical assessment performed for LBI participants. Subjects performed a symmetrical lift and replace task in two reaches. Pattern recognition techniques were applied to normalized activation amplitude patterns to extract key recruitment strategies. Mixed model ANOVAs tested for effects (p < 0.05). Despite similar task performance, significantly (p < 0.05) different recruitment strategies were observed for the LBI group. There were higher activation amplitudes for LBI subjects in all muscles (except posterior external oblique) and greater co-activation between abdominal and back extensor sites compared to controls. Local abdominal and back extensor sites showed altered responses to increased physical demands in the LBI group. Despite outcomes indicating recovery, the LBI group had altered neuromuscular patterns compared to asymptomatic controls supporting that residual alterations remain following recovery.  相似文献   

9.
《Journal of Asia》2014,17(4):737-743
An autonomous robot (Cabbot) was built to control insect pests in a plastic greenhouse and utilized to sample adult whiteflies (Bemisia tabaci) on paprika plants (Capsicum annum var. angulosum). To accomplish this, a sampling device consisting of an air compressor for pest agitation, a sticky trap (100 mm × 150 mm) and an image processing system for pest identification were installed on the Cabbot. The sampling precision of the Cabbot (D = 0.16) was higher than that of the sticky trap (D = 0.19) when sampling of adult white flies was conducted in caged pots. The Cabbot could also collect a substantial number of individuals within a short duration (3 minutes). The collection efficiency (i.e., percent of samples collected at least n (1 in this case) individuals to the total sample number) of insects by the Cabbot was markedly high at low population size, showing approximately 30% when the population size was ≤ 16 individuals per plant. The sampling precision and collection efficiency suggested that the Cabbot is effective in local, short-term sampling and could be used for early warning of pest occurrences.  相似文献   

10.
Investigate reflex responses in muscles throughout the lower limb and low back during sudden inversion perturbations in individuals with and without Functional Ankle Instability (FAI) while walking. Forty subjects participated in the study. Surface electromyogram recordings were obtained from the fibularis (FIB), gluteus medius (GM), erector spinae (ES), and sternocleidomastoid (SCM) of the injured/matched side as well as the uninjured/matched contralateral side (FIB_CLS, GM_CLS, or ES_CLS). Latency and amplitude data were collected while subjects were walking on a custom-built perturbation walkway. The onset of the short-latency stretch reflex of the FIB was significantly later in the injured side of the FAI individuals when compared to the control group (P = 0.009). Both the short and long latency reflex amplitude was significantly smaller in the FIB muscle in the FAI group than in the control group (P < 0.008). No significant differences in latency or amplitude reflex responses were identified between the two groups in the GM, ES, FIB_CLS, GM_CLS, or ES_CLS (P > .05). Interpretation of these results indicate that during a dynamic perturbation task individuals with FAI demonstrate longer fibularis muscle latencies on the injured side while no significant changes in the proximal muscle groups. Additionally, short and long latency reflex amplitude was significantly decreased in FAI individuals.  相似文献   

11.
A novel series of monoamine reuptake inhibitors, the 1-amino-3-(1H-indol-1-yl)-3-phenylpropan-2-ols, have been discovered by combining virtual and focused screening efforts with design techniques. Synthesis of the two diastereomeric isomers of the molecule followed by chiral resolution of each enantiomer revealed the (2R,3S)-isomer to be a potent norepinephrine reuptake inhibitor (IC50 = 28 nM) with excellent selectivity over the dopamine transporter and 13-fold selectivity over the serotonin transporter.  相似文献   

12.
BackgroundThe body mass index (BMI) is based on the original concept that body weight increases as a function of height squared. As an indicator of obesity the modern BMI assumption postulates that adiposity also increases as a function of height in states of positive energy balance.ObjectiveTo evaluate the BMI concept across different adiposity magnitudes, in both children and adults.MethodsWe studied 975 individuals who underwent anthropometric evaluation: 474 children and 501 adults. Tetrapolar bioimpedance analysis was used to assess body fat and lean mass.ResultsBMI significantly correlated with percentage of body fat (%BF; children: r = 0.893; adults: r = 0.878) and with total fat mass (children: r = 0.967; adults: r = 0.953). In children, body weight, fat mass, %BF and waist circumference progressively increased as a function of height squared. In adults body weight increased as a function of height squared, but %BF actually decreased with increasing height both in men (r = −0.406; p < 0.001) and women (r = −0.413; p < 0.001). Most of the BMI variance in adults was explained by a positive correlation of total lean mass with height squared (r2 = 0.709), and by a negative correlation of BMI with total fat mass (r = −0.193).ConclusionsBody weight increases as a function of height squared. However, adiposity progressively increases as a function of height only in children. BMI is not an ideal indicator of obesity in adults since it is significantly influenced by the lean mass, even in obese individuals.  相似文献   

13.
In-depth investigations on diapause behaviour of Z. bicolorata revealed that the adults entered diapause at any time from August to December and that the number peaked (42.00%) during the last half of November. The percentage of adults entering diapause increased with a decrease in day length. Weight of diapausing adults was significantly higher than weight of non-diapausing adults. The percentage of adults undergoing diapause at 30 °C was significantly lower than those undergoing diapause at 15 and 25 °C. The percentage of adults burrowing increased with increasing moisture. In silty soil and soil with high organic matter, 46.7% and 49.2% of adults entered diapause, respectively, whereas in sandy soil, only 23.5% of adults entered diapause. When newly emerged beetles were exposed to 5 μg of human insulin 30/70, a significantly lower percentage of treated adults underwent diapause compared to untreated adults under both feeding and no feeding conditions. Insulin treatment also influenced the emergence period from diapause (93.92 ± 1.73 days), percent emergence (81 ± 1.54%) and fecundity/month (512.7 ± 25.38 eggs) of Z. bicolorata in treated adults as compared to untreated adults (109.05 ± 2.2, 74.00 ± 1.82 and 438.3 ± 19.33 eggs, respectively). However, there was no significant impact of insulin on adult longevity. These findings are of great utility in the biological suppression of Parthenium as it will enhance the effectiveness of this beetle through manipulation of diapause.  相似文献   

14.
Little is known regarding the modulation and the plasticity of the neural pathway interconnecting elements of the central nervous system and skeletal muscle in resistant-trained individuals. The aim of the study was to compare corticospinal and spinal responses measured during dynamic muscle contractions of the tibialis anterior in resistance trained (RT) and un-trained (UT) males. Nine UT and 10 RT male volunteers reported to the laboratory 24 h following a familiarisation session. Motor evoked potentials (MEPs) and the cortical silent period were evoked using transcranial magnetic stimulation at a range of contraction intensities and was delivered as the ankle passed 90° during shortening and lengthening contractions. The Hoffmann reflex (H-reflex) and V-waves were evoked with peripheral nerve stimulation. Despite the RT group being significantly stronger during shortening (28%; P = 0.023: CI = 1.27–15.1 N m), lengthening (25%; P = 0.041: CI = 0.27–17.0 N m) and isometric muscle actions (20%; P = 0.041; CI = 0.77–14.9 N m), no differences between the groups existed for corticospinal or spinal variables. Lack of detectable differences between RT and UT individuals may be linked to minimal exposure to task specific, isolated high intensity resistance training of the TA muscle.  相似文献   

15.
Although substantial upper extremity (U/E) muscular efforts are required when individuals with spinal cord injury (SCI) perform sitting pivot transfers, little is known about the electromyographic (EMG) activation patterns of key shoulder and elbow muscles solicited during the performance of this functional task. The aims of this study were to examine the EMG activation patterns of U/E muscles in 10 males with SCI, and to compare them across sitting pivot transfers performed toward seats of different heights (low, same, high). EMG data from the biceps, triceps, deltoid, pectoralis major and latissimus dorsi were recorded bilaterally. Transfers were divided into pre-lift, lift, and post-lift phases. Each phase was time- and amplitude-normalized using a mean dynamic EMG approach. Similar EMG activation patterns were found across the different transfers for all muscles (rmean = 0.942–0.991), whereas moderate to high inter-subject variability (CV: 20.9–70.6%) was reported for the different muscles and transfers. Peak EMG occurred earlier at the trailing U/E compared to the leading one, and was observed around seat-off for most of the muscles. When transfer to a high target seat was compared to transfer to one of the same height, significantly higher relative EMG values were observed at the biceps (mean: 1.64 vs. 1.00) of the leading U/E as well as the deltoid (mean: 1.20 vs. 1.00) and pectoralis major (mean: 1.20 vs. 1.00; peak: 2.27 vs. 1.79) of the trailing U/E. Transferring to a low target seat did not lead to lower muscular demand than transferring to one of the same height (P > 0.05). These results indicate that coordinated and higher muscular efforts were generated at the trailing deltoid and pectoralis major when transferring to a high target seat compared to one of similar height. Higher muscular efforts were also developed at the leading biceps when transferring to a high target seat compared to a leveled one. Lowering the target seat with respect to the initial seat had no favorable effect on muscular demand.  相似文献   

16.
Cladonia verticillaris lichen lectin (ClaveLL) was isolated through Sephadex G-100 gel filtration chromatography and characterized as a pure lectin through ÄKTA-FPLC and HPLC systems. The lichen extract (LE), protein fraction (F1) and ClaveLL were assayed to evaluate their potential insecticidal and/or repellence activities on termite Nasutitermes corniger. LE, F1 and ClaveLL were evaluated for hemagglutinating activity (HA), protein concentration and presence of secondary metabolites; preparations and active ClaveLL, free of secondary metabolites, were able to induce termite mortality. ClaveLL LC50 values after 10 days for workers and soldiers were 0.196 and 0.5 mg ml?1, respectively. C. verticillaris preparations are potential tools for researches involving control of termites (or other insects) of economic interest to wooden industry or agriculture as well as preservation of plant species that are targets of termites or other plagues.  相似文献   

17.
Background: Hepatoblastoma is a malignant embryonal tumor typically diagnosed in children younger than five years of age. Little is known on hepatoblastoma etiology. Methods: We matched California Cancer Registry records of hepatoblastomas diagnosed in children younger than age 6 from 1988 to 2007 to birth records using a probabilistic record linkage program, yielding 261 cases. Controls (n = 218,277), frequency matched by birth year to all cancer cases in California for the same time period, were randomly selected from California birth records. We examined demographic and socioeconomic information, birth characteristics, pregnancy history, complications in pregnancy, labor and delivery, and abnormal conditions and clinical procedures relating to the newborn, with study data taken from birth certificates. Results: We observed increased risks for hepatoblastoma among children with low [1500–2499 g, Odds Ratio (OR) = 2.02, 95% confidence interval (CI) 1.29–3.15] and very low birthweight (<1500 g, OR = 15.4, 95% CI 10.7–22.3), preterm birth <33 weeks (OR = 7.27, 95% CI 5.00, 10.6), small size for gestational age (OR = 1.75, 95% CI 1.25–2.45), and with multiple birth pregnancies (OR = 2.52, 95% CI 1.54–4.14). We observed a number of pregnancy and labor complications to be related to hepatoblastoma, including preeclampsia, premature labor, fetal distress, and congenital anomalies. Conclusion: These findings confirm previously reported associations with low birthweight and preeclampsia. The relation with multiple birth pregnancies has been previously reported and may indicate a relation to infertility treatments.  相似文献   

18.
Predation is a key source of seed mortality in many weed species and thus is a part of natural control. In the field, the intensity of seed predation by invertebrates varies during the course of a year. One source of this variation is fluctuations in ambient temperature. Here, the effect of temperature on seed consumption is investigated for the first time, using two abundant carabid seed predators, Pseudoophonus rufipes and Harpalus affinis (Coleoptera: Carabidae), and dandelion (Taraxacum officinale) as a model system. Field collected individuals were sexed, kept at one of six constant temperatures between 10 and 28 °C and provided with a surplus of seed. Seed consumption was recorded over a period of 4 days. Averaged over all the temperatures, the smaller H. affinis consumed 12.2 seeds day?1 and larger P. rufipes 29 seeds day?1. On average, females consumed more seeds than males. Seed consumption by both species increased with temperature. In H. affinis the increase was linear and different for males and females. In P. rufipes the consumption was similar in both sexes but curvilinear because there was no further increase in consumption above 20 °C. Assuming a linear relationship between temperature and consumption at up to 20 °C we calculated the temperature at which seed consumption ceased (?0.1 to 0.3 °C in H. affinis and 6.3–6.9 °C in P. rufipes) and the increment in seed consumption per 1 °C increase in temperature above this threshold (0.4–1.0 and 1.5–4.2 seeds individual?1 day?1, respectively) for the two species. Thus, it is possible to calculate the average daily consumption of each species over a range of temperatures up to 20 °C.  相似文献   

19.
PurposeThe aim of this study was to investigate the influence of the TNF -308 G/A polymorphism in the promoter region of the tumor necrosis factor-α gene on the susceptibility and severity of rheumatoid arthritis (RA) in individuals from the Brazilian Amazon.MethodsA total of 323 individuals—192 healthy controls without arthritis and 131 individuals suffering from arthritis—were genotyped for this polymorphism using a methodology based on PCR-RFLP.ResultsThe frequency of the A allele (TNF2) in rheumatoid arthritis sufferers was not significantly higher than in the controls (p = 0.926; OR = 0.97; confidence interval 0.54–1.76). However, using a logistic regression model, when the patients were stratified according to whether the manifestations were preponderantly articular or systemic, there was a strong association between the TNF2 allele and systemic arthritis (p = 0.001; OR = 5.89; confidence interval = 1.98–17.5) as well as the use of anti-TNF immunotherapy (p = 0.023; OR = 1.10; confidence interval = 1.00–1.14). The main factors that were found to influence the risk of extra-articular disease were age greater than or equal to 60 years (p = 0.008; OR = 4.06; confidence interval = 1.45–11.38), disease duration greater than 10 years (p = 0.031; OR = 3.10; confidence interval = 1.11–8.63) and positive rheumatoid factor (p = 0.035; OR = 2.07; confidence interval = 1.05–4.09).ConclusionsThese results suggest that the TNF2 allele is associated with the more serious forms of the disease in individuals from the Brazilian Amazon but not with a risk for developing RA.  相似文献   

20.
Grains are often stored in jute bags in developing countries, especially in Africa, as well as in small quantities in bulk. Parasitoids suitable for biological control of stored-product pests should be able to find their hosts in bulk grain or in jute bags over a certain distance in a warehouse containing stacks of bagged grain. The potential of using Lariophagus distinguendus for the biological control of Sitophilus zeamais was assessed in maize stored in jute bags and bulk grain. The ability of the parasitoid to penetrate the jute cloth and the grain mass and parasitize its host was studied under controlled conditions of 25 ± 1 °C and 65 ± 5% RH. Experiments were carried out in small 5-kg jute bags containing 28 d old S. zeamais larvae within infested maize kernels, and in cylinders filled with maize grains and containing caged hosts at different depths. L. distinguendus parasitized S. zeamais in the jute bags and in the storage cylinders at various depths. In the jute bag experiment, out of the 60 L. distinguendus adults released, a mean ± SD of 7.03 ± 1.78% and 6.34 ± 1.01% of the 40 females and of the 20 males released, respectively, entered the jute bags. Significantly, no differences were found between the female and male L. distinguendus that entered the bags. Mean reduction of S. zeamais in the jute bags by parasitoids was 81%. The parasitic wasps also significantly reduced the emergence of S. zeamais in bulk maize. At depths of 20–45 cm from the grain surface, mean reduction of S. zeamais was 74%, while from 95 to 100 cm, mean reduction was 34%. When results from depths lower than 50 cm were pooled and compared with pooled data from depths higher than 90 cm, there was a significant reduction in parasitism at depths of more than 90 cm. For depths below 50 cm a mean of 5.3 L. distinguendus adult offspring per cage emerged compared with a mean of 2.6 at depths of more than 90 cm. These results support the approach to utilize L. distinguendus as a component in the integrated control of S. zeamais in bagged or bulk stored maize.  相似文献   

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