The purpose of this investigation was to compare valgus/varus knee angles during various jumps and lower body strength between males and females relative to body mass. Seventeen recreationally active females (age: 21.94 ± 2.59 years; height: 1.67 ± 0.05 m; mass: 64.42 ± 8.39 kg; percent body fat: 26.89 ± 6.26%; squat one-repetition maximum: 66.18 ± 19.47 kg; squat to body mass ratio: 1.03 ± 0.28) and 13 recreationally active males (age: 21.69 ± 1.65 years; height: 1.77 ± 0.07 m; mass: 72.39 ± 9.23 kg; percent body fat: 13.15 ± 5.18%; squat one-repetition maximum: 115.77 ± 30.40 kg; squat to body mass ratio: 1.59 ± 0.31) performed a one-repetition maximum in the squat and three of each of the following jumps: countermovement jump, 30 cm drop jump, 45 cm drop jump, and 60 cm drop jump. Knee angles were analysed using videography and body composition was analysed by dual-energy X-ray absorptiometry to allow for squat to body mass ratio and squat to fat free mass ratio to be calculated. Significant differences (P ≤ 0.05) were found between male and female one-repetition maximum, male and female squat to body mass ratio, and male and female squat to fat free mass ratio. Significant differences were found between male and female varus/valgus knee positions during maximum flexion of the right and left leg in the countermovement jump, drop jump from 30 cm, drop jump from 45 cm, and drop jump from 60 cm. Correlations between varus/valgus knee angles and squat to body mass ratio for all jumps displayed moderate, non-significant relationships (countermovement jump: r = 0.445; drop jump from 30 cm: r = 0.448; drop jump from 45 cm: r = 0.449; drop jump from 60 cm: r = 0.439). In conclusion, males and females have significantly different lower body strength and varus/valgus knee position when landing from jumps. 相似文献
The experimental results show that aldehydes are harmful to plant growth in aqueous culture solutions, in nutrient solutions, in soil in pots, and in soil in the field.The effects of six aldehydes—namely, salicylic aldehyde, vanillin, benzaldehyde, heliotropine, formaldehyde, and paraformaldehyde—were studied in nutrient-culture solutions and each proved to be detrimental to plant growth.The effect of the compounds varied according to the composition of the nutrient solutions. Salicylic aldehyde was least harmful in solutions composed of a high percentage of phosphates. Vanillin was least harmful in solutions with a high percentage of nitrates. Benzaldehyde was about equally harmful in all the nutrient solutions. It was slightly more harmful, however, in the high nitrate solutions than in the mainly phosphatic or potassic cultures. Paraformaldehyde was also least harmful in the phosphate culture, but formaldehyde and heliotropine showed harmful effects to an equal degree in almost all cultures, regardless of their composition.Salicylic aldehyde and vanillin were found to occur in soils quite frequently, especially in soils of low productivity. The isolated substance from the soils was harmful to plants when dissolved in aqueous solution.The two aldehydes were harmful in some soils and not in others. The field studies show that the added aldehydes disappeared in some soils and not in others. There was no harmful action where the aldehydes were destroyed. The soils in which the aldehydes were destroyed have strong biological activities, good oxidation powers, and are fertile.The results of the experimental work presented in this paper further show that unfertile soils, where due to the presence of harmful aldehydes, can be made productive by good drainage and by the use of lime and certain fertilizers. This is demonstrated, first, by the growth of plants in nutrient solutions, where it is shown that phosphates partially overcome the bad effects of salicylic aldehyde, and that nitrates ameliorate the harmfulness of another aldehyde, vanillin. Second, by the more normal absorption of phosphates by plants growing in solutions containing salicylic aldehyde. Third, by the growth of plants in soil in pots, which shows that the harmful action of salicylic aldehyde is partially overcome by lime and phosphates and the effects of vanillin by lime and nitrate fertilizers. Fourth, by the growth of plants in field soils to which aldehydes were added, which again shows that lime and phosphates lessen the harmfulness of salicylic aldehyde and lime and nitrates alter the effects of vanillin. Fifth, by chemical tests in which it was shown that salicylic aldehyde, when added to a soil, was destroyed where lime and phosphates were added, and vanillin was destroyed where lime and nitrates were added. Sixth, by the improved productivity from the addition of lime and phosphates to a soil in which salicylic aldehyde was naturally formed and persisted for a period of years. 相似文献
Appetitive, aversive and avoidance responses to a flavoured solution in distinct contexts were examined. Rats placed in either
a white or black box were given access to saccharin. Consumption was followed by an injection of a toxin in one but not the
other box. Rats showed more aversive responses in anticipation of and during the presentation of saccharin in the box paired
with the toxin than in the box paired with vehicle. The reverse was true for appetitive responses. The acquisition of conditioned
avoidance paralleled the acquisition of aversive and appetitive responses. These findings demonstrate that the toxin does
not have to overlap exposure to contextual cues to produce conditioned aversive responses, that the aversive and appetitive
responses to a flavour can be modulated by visually distinct environments that predict the toxin, and that conditioned avoidance
and conditioned aversions develop simultaneously during acquisition. Thus, environmental cues can modulate anticipatory nausea
and may prove helpful in the control of nausea in clinical settings. 相似文献
Postsecondary students increasingly enroll in online courses, which have the potential to further democratize higher education by expanding access for historically underserved populations. While a number of studies have investigated student outcomes in online courses, past data limitations have hindered robust examination of a potential mechanism underlying the decision to enroll in an online course: access to high speed broadband. With data from the National Broadband Map and IPEDS, I fit a number of Bayesian regression models to investigate the relationship between various measures of broadband access—download speed, upload speed, and the number of providers—and the number of students who take online courses at public colleges and universities with open admissions policies. Results show that increases in broadband speed at the lower end of the speed spectrum are positively associated with the number of students who take some of their courses online, but that the marginal gain diminishes as speeds increase. This finding suggests that there may be a minimum threshold of necessary broadband access, beyond which increases in speed become a less important factor in the take up of online coursework. Open admissions colleges seeking to improve access for local students through increased online course offerings should consider broadband access in the area, particularly if the targeted populations live in communities with low average broadband speeds.
Research findings suggest that most students who have foreign language learning problems have language-based difficulties
and, in particular, phonological processing problems. Authors of the present study examined pre- and posttest scores on native
language and foreign language aptitude tests of three groups of at-risk high school students enrolled in special, self-contained
sections of first-year Spanish. Two groups were instructed using a multisensory structured language (MSL) approach. One of
the groups was taught in both English and Spanish (MSL/ES), the other only in Spanish (MSL/S). The third group (NO-MSL) was
instructed using more traditional second language teaching methodologies. Significant gains were made by the MSL-ES group
on measures of native language phonology, vocabulary, and verbal memory and on a test of foreign language aptitude; the MSL/S
group made significant gains on the test of foreign language aptitude. No significant gains on the native language or foreign
language aptitude measures were made by the NO-MSL group. Implications for foreign language classroom instruction of at-risk
students are discussed. 相似文献
This study examined strategies teachers reported using to support friendships among young children in inclusive early childhood classrooms. The teachers included 25 general early childhood educators from 9 child care centers and 20 early childhood special educators from 9 specialized programs. The Playmates and Friends Questionnaire for Teachers documented the number and nature of children’s friendships and teachers’ reported use of 11 different strategies to support individual friendships. Overall, the friendship strategies that teachers reported using most frequently included providing sufficient free choice time, allowing children to form their own friendships, and commenting on the play between friends. The majority of teachers reported rarely using two strategies: arranging for children to play together outside of the classroom and allowing two friends to exclude other children from their play. Teachers reported using more active friendship strategies to support dyads in which one or both children had special needs. Implications of these findings to support friendship formation in inclusive early childhood settings and directions for future research are presented. 相似文献
In adult literacy programs today, well-intentioned but inadequately prepared volunteer tutors are being matched with learning
disabled adult students without the benefit of receiving training from experts in the field of language/learning disabilities.
The collaboration of adult literacy providers and learning specialists is obviously the most resourceful, yet most untried,
solution to a problem that is plaguing volunteer-based programs across the country: meeting the needs of learning disabled
adults. One adult literacy program—READ/San Diego of the San Diego Public Library—recognized that its volunteer tutors needed
training in special instructional methods to teach adults who evidence learning disabilities. Accordingly, the program’s administrator
obtained the services of specialists to develop a learning disabilities tutor-training module. This article (1) presents an
overview of preservice volunteer training at READ/San Diego; (2) discusses informal assessment procedures that help identify
possible language/learning disabilities in adults and provide valuable information for instructional planning; and (3) describes
selected multisensory teaching techniques designed especially for adults who “learn differently.” 相似文献