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11.
This laboratory activity was designed to strengthen our Food and Nutritional Science students’ knowledge of biochemistry concepts and the relationship between these concepts and food science. The result was a laboratory experience in which biochemistry concepts are taught using yogurt as a model, in order to link those concepts to food safety, an important area of food science. The students employed a colorimetric method to measure the lactase activity of bacterial strains found in commercial yogurts and were encouraged to relate the activity to bacterial lactic acid production, fermentation, and food safety. Students were assessed with pre‐ and post‐test exams, laboratory reports, class performance rubrics, and the Intrinsic Motivation Inventory (IMI). The result demonstrated that the students successfully completed the learning objectives and were motivated during the activity. This exercise could be used as a template for a simplified and engaging way to introduce food science majors, as well as other students, to complex biochemistry and molecular biology concepts using food, particularly yogurt, as a model.  相似文献   
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Parental involvement in education remains important for facilitating positive youth development. This study conceptualized parental involvement as a multidimensional construct—including school‐based involvement, home‐based involvement, and academic socialization—and examined the effects of different types of parental involvement in 10th grade on student achievement and depression in 11th grade (approximately ages 15–17 years). In addition, this study tested whether parental involvement influenced adolescent outcomes by increasing their academic engagement in school. A total of 1,056 adolescents participated in the study (51% males; 53% European American, 40% African American, and 7% other). Parental involvement was found to improve academic and emotional functioning among adolescents. In addition, parental involvement predicted adolescent academic success and mental health both directly and indirectly through behavioral and emotional engagement.  相似文献   
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Abstract

In this study, we compared the isokinetic torques of hip flexors/extensors and abductors/adductors in soccer players suffering from osteitis pubis (OP), with normal soccer players. Twenty soccer male athletes with OP and 20 normal soccer athletes were included in this study. Peak torque/body weight (PT/BW) was recorded from hip flexor/extensor and abductor/adductor muscles during isokinetic concentric contraction modes at angular velocity of 2.1 rad · s?1, for both groups. The results showed a significant difference between the normal and OP groups for hip flexors (< 0.05). The normal group had significant, lower PT/BW value than the OP group for their hip flexors (< 0.05). The hip flexor/extensor PT ratio of OP affected and non-affected limbs was significantly different from that of normal dominant and non-dominant limbs. There were no significant differences between the normal and OP groups for hip extensor, adductor and abductor muscles (> 0.05). Regarding the hip adductor/abductor PT ratio, there was no significant difference between the normal and OP groups of athletes (> 0.05). The OP group displayed increase in hip flexor strength that disturbed the hip flexor/extensor torque ratio of OP. Therefore, increasing the hip extensor strength should be part of rehabilitation programmes of patients with OP.  相似文献   
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The nematodes (worms) Caenorhabditiselegans and Caenorhabditisbriggsae are well-known model organisms to study the basis of animal development and behaviour. Their sinusoidal pattern of movement is highly stereotypic and serves as a tool to monitor defects in neurons and muscles that control movement. Until recently, a simple yet robust method to initiate movement response on-demand did not exist. We have found that the electrical stimulation in a microfluidic channel, using constant DC electric field, induces movement (termed electrotaxis) that is instantaneous, precise, sensitive, and fully penetrant. We have further characterized this behaviour and, in this paper, demonstrate that electrotaxis can also be induced using a pulse DC electric signal. Worms responded to pulse DC signals with as low as 30% duty cycle by moving towards the negative electrode at the same speed as constant DC fields (average speed of C. elegans?=?296?±?43?μm/s and C. briggsae?=?356?±?20?μm/s, for both constant and pulse DC electric fields with various frequencies). C. briggsae was found to be more sensitive to electric signals compared to C. elegans. We also investigated the turning response of worms to a change in the direction of constant and pulse DC signals. The response for constant DC signal was found to be instantaneous and similar for most worms. However, in the case of pulse DC signal, alterations in duty cycle affected the turning response time as well as the number of responding worms. Our findings show that pulse DC method allows quantitative measurement of response behaviour of worms and suggest that it could be used as a tool to study the neuronal basis of such a behaviour that is not observed under constant DC conditions.  相似文献   
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This paper addresses the output regulation problem for a class of preview control systems, and derives a state feedback law which suppresses the steady-state error caused by the excitation from polynomial or sinusoidal exogenous inputs. Recently, the output regulation condition for the broader class of distributed parameter systems is characterized via the operator regulator equation. We show that a solution of the operator regulator equation specialized to the preview control system is obtained by solving the matrix regulator equation, and provide the state feedback law which attenuates the transient error optimally with respect to an LQ (Linear Quadratic) performance index.  相似文献   
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