An analysis of review content and reviewer variables that contribute to review helpfulness

Review helpfulness is attracting increasing attention of practitioners and academics. It helps in reducing risks and uncertainty faced by users in online shopping. This study examines uninvestigated variables by looking at not only the review characteristics but also important indicators of reviewers. Several significant review content and two reviewer variables are proposed and an effective review helpfulness prediction model is built using stochastic gradient boosting learning method. This study derived a mechanism to extract novel review content variables from review text. Six popular machine learning models and three real-life Amazon review data sets are used for analysis. Our results are robust to several product categories and along three Amazon review data sets. The results show that review content variables deliver the best performance as compared to the reviewer and state-of-the-art baseline as a standalone model. This study finds that reviewer helpfulness per day and syllables in review text strongly relates to review helpfulness. Moreover, the number of space, aux verb, drives words in review text and productivity score of a reviewer are also effective predictors of review helpfulness. The findings will help customers to write better reviews, help retailers to manage their websites intelligently and aid customers in their product purchasing decisions.     

Intensity of parasitic infestation in silver carp, Hypophthalmichthys molitrix

Silver carp, Hypopthalmichthys molitrix is one of the most economically valuable fish species in Bangladesh. However, its production is often hindered by parasite-induced mortality. The present study reports the intensity of parasitic infestation in 216 specimens of H. molitrix collected from different fish markets in Rajshahi City, Bangladesh. Nine different parasite species (Trichodina pediculatus, Dactylogyrus vastator, Ichthyophthirius multifilis, Gyrodactylus elegans, Lernaea sp., Apiosoma sp., Myxobolus rohitae, Camallanus ophiocephali, and Pallisentis ophiocephali) were recovered from the gill, skin, stomach, and intestine of host fish. The highest level of infection was observed for host skin, while lower levels were observed for host gill, stomach, and intestine. The results also revealed that the intensity of parasite infection in different organs of H. molitrix varied with the season. In particular, the highest levels of infection were recorded during the winter period (November-February), when fish are most susceptible to parasites. The findings of the study will help in the management and conservation of H. molitrix.     

Effects of Classroom Assessment Practices on Students' Achievement Goals

This study examined the effects of classroom assessment practices on students' achievement goals. The study included 1,636 ninth grade students and 83 science teachers from Muscat public schools in Oman. Results from hierarchical linear modeling techniques showed that class contextual features and teachers' teaching experiences and assessment practices interacted significantly with students' characteristics in influencing students' achievement goals. Recommendations, implications, and suggestions for practice and future research are discussed.     

Effects of concomitant diabetes mellitus and hyperthyroidism on testicular and epididymal histoarchitecture and steroidogenesis in male animals

This study evaluated the effects of comorbid disorders of diabetes and hyperthyroidism in the adult male mice. In total, 32 ICR strain mice were equally distributed into four groups: control (C), diabetic (D), diabetic-plushyperthyroid (DH), and hyperthyroid (H). Mice allocated for diabetes received a single intraperitoneal injection of streptozotocin (STZ) at 200 mg/kg body weight. At the onset of diabetes, one group of mice was concomitantly injected levothyroxine (LT4; 0.3 mg/kg body weight) and the other set of animals received the same treatment independently on a daily basis. The body weight, as well as the testicular and epididymal weights, was reduced markedly in D and DH mice. Higher trends of blood glucose levels were seen in the DH group, in comparison to euthyroid diabetic mice. Thyroid hormones could exert a transient effect on blood glucose homeostasis by altering the serum blood glucose level in diabetic patients. Histomorphometric analysis showed increased luminal sizes of seminiferous tubules, along with decreased epithelial height and atrophic changes in germinal stem cells in the testis of DH and H mice. Caput epididymis of DH mice showed extensive compaction of principal cells, loss of stereocilia, lipid vacuolization, and inflammatory infiltrations; however, damaged tubular integrity, packed clear cells, exfoliated cells, and round spermatids were profoundly noticed in the cauda epididymis. Hyperthyroidism elevated the serum testosterone levels in H and DH mice and produced critical damages to the histoarchitecture of the epididymis. Collectively, this experiment endeavored to mimic the polyglandular autoimmune syndrome, which will be helpful to better understand the reasons for male infertility in diabetic-cum-hyperthyroid patients.     

Algebraic Generalization Strategies Used by Kuwaiti Pre-service Teachers

This study reports on the algebraic generalization strategies used by elementary and middle/high school pre-service mathematics teachers in Kuwait. They were presented with 9 tasks that involved linear, exponential, and quadratic situations. The results showed that these pre-service teachers had difficulty in generalizing algebraic rules in all 3 types of tasks. The most difficult problems were those involving exponents; they seemed to confuse exponential growth with the multiplication of n. Although they used several strategies such as explicit, recursive, and chunking, they tended to rely on explicit reasoning. They saw the explicit rule as a quick and easy rule to be used. In order to improve students’ understanding of algebraic reasoning, we must improve the understating of generalization. Teachers’ programs should put more emphasis on the type of content that teachers need to learn rather than on how much mathematics credits teachers need.     

Inactivation of infectious bursal disease virus by binary ethylenimine and formalin

In this experiment conducted to study the inactivation dynamics of infectious bursal disease virus （IBDV） by binary ethylenimine （BEI） in comparison with formalin, IBDV was isolated from the bursa of infected chickens and its confirmation was done by agar gel precipitation test. Viral suspensions were subjected to inactivation with BEI and formalin for pre-set time in- tervals. BEI was employed at concentrations of 0.001 and 0.002 mol/L while formalin was used at 0.1% and 0.2%. Sampling was done at 6, 12, 24, 36 and 48 h of incubation and samples were tested for their inactivation status in 9-day-old embryonated eggs and 3-week-old broiler chickens. IBDV was completely inactivated by 0.001 and 0.002 mol/L BEI after 36 h of incubation at 37℃, whereas formalin at 0. 1% and 0.2% concentrations inactivated IBDV in 24 h.     

Teacher-student development in mathematics classrooms: Interrelated zones of free movement and promoted actions

This paper applies and extends Valsiner’s ‘zone theory’ (zones of free movement and promoted actions) through an examination of an intervention to establish inquiry communities in primary mathematics classrooms. Valsiner’s zone theory, in a classroom setting, views students’ freedom of choice of action and thought as mediated by the teacher. The extension of this theory adds that teachers’ freedom of choice of action and thought is mediated by ‘significant others’ and also by the actions of students with new freedoms. The paper presents necessary theoretical constructs and provides extracts from lessons and from teacher-teacher collaboration to illustrate the theoretical extension.     

Examining the relations of time management and procrastination within a model of self-regulated learning

The primary goal of this study was to investigate whether college students’ academic time management could be used to understand their engagement in traditional and active forms of procrastination within a model of self-regulated learning. College students (N = 446) completed a self-report survey that assessed motivational and strategic aspects of self-regulated learning, time management, and procrastination. Results of regression analyses indicated that self-efficacy and metacognitive strategies initially were significant predictors of traditional and active forms of procrastination. Incorporating time management in the analyses increased the amount of the variance explained and, even in the presence of the motivation and strategy variables, time management emerged as an important predictor of both traditional and active forms of procrastination. Findings support the conclusion that academic time management is a key aspect of self-regulated learning and, as such, it can be useful for understanding the extent to which college students procrastinate when doing their academic work.     

Application of automated image analysis to the identification and extraction of recyclable plastic bottles

An experimental machine vision apparatus was used to identify and extract recyclable plastic bottles out of a conveyor belt. Color images were taken with a commercially available Webcam, and the recognition was performed by our homemade software, based on the shape and dimensions of object images. The software was able to manage multiple bottles in a single image and was additionally extended to cases involving touching bottles. The identification was fulfilled by comparing the set of measured features with an existing database and meanwhile integrating various recognition techniques such as minimum distance in the feature space, self-organized maps, and neural networks. The recognition system was tested on a set of 50 different bottles and provided so far an accuracy of about 97% on bottle identification. The extraction of the bottles was performed by means of a pneumatic arm, which was activated according to the plastic type; polyethylene-terephthalate （PET） bottles were left on the conveyor belt, while non-PET bottles were extracted. The software was designed to provide the best compromise between reliability and speed for real-time applications in view of the commercialization of the system at existing recycling plants.