Number Manipulation Strategy: A Model of Experiential Instruction and Interest in Arithmetic Learning of Pupils of Lower Basic Level in Enugu State, Nigeria

The study investigated the efficacy of the number manipulation strategy (NUMAS) as a model of experiential instruction and interest in arithmetic learning for pupils of lower basic levels. The population of the study consisted of 1205 lower basic III level pupils of the 2018/2019 session in Igbo-Etiti Local Government Area (L.G.A.) of Enugu State. A sample of 121 primary five pupils from 4 schools out of 53 primary schools in the study area was randomly sampled. The 121 pupils were composed of 42 males and 79 females used for the study. The study was guided by four research questions and four hypotheses. The hypotheses were tested at a p<.05 level of significance. The instruments used for the study were Arithmetic Test (ART) and Mathematics Interest Inventory Questionnaire (MIIQ) developed by the researcher. The ART and MIIQ instruments were faces validated by experts and their reliability indexes were 0.85 and 0.79 respectively, established using Cronbach alpha and split-half methods respectively. The data obtained with the instruments were analyzed using mean, standard deviations (SD), t-test and analysis of covariance (ANCOVA) statistics. Mean and SD was used in answering the research questions, while t-test and ANCOVA statistics were used in testing the hypotheses at P<.05 level of significance. The findings of the study showed that NUMAS is effective in teaching arithmetic, especially in enhancing the addition and subtraction skills acquisition of the pupils. Gender was found not to be a significant factor of variance in arithmetic achievement when the teaching of arithmetic is NUMAS based. The use of NUMAS was recommended to teachers, lower basic mathematics textbook authors and stakeholders in education, to ensure that NUMAS is adopted and adapted for use in Mathematics classroom instruction and learning.

Spatial Strategies Used by Students With Visual Impairments to Solve Questions of Spatial Visualization

Introduction: This study examines the spatial abilities of middle school students with visual impairments (i.e., blindness and low vision) in the context of spatial visualization. The study also aims to examine the strategies used by such students in solving questions requiring spatial ability. Methods: Participants comprised eight students with visual impairments attending the 8th grade of a school in Ankara, Turkey, which teaches students with visual impairments. The data collection tool is composed of eight questions under the guidance of the definition for spatial visualization. Question types belonging to the spatial visualization subcomponent were organized in four topics: 2D rotation, 3D rotation, paper folding, and cube folding. Results: It was observed that students with visual impairments used mental rotation and key feature strategies for 2D rotation questions. They used the key feature strategy for 3D rotation questions and the mental manipulation strategy for cube folding and paper folding questions. Discussion: In this study, it was identified that strategies used by students with visual impairments show similarities with spatial strategies defined in the literature as used by students without visual impairments. Of all the other types of questions, the most successful question of students with visual impairments is the paper folding question. Implications for practitioners: The results of this article can help teachers become aware of the kind of difficulties that students with visual impairments encounter when they try to solve questions that require spatial ability.

Laser fabrication of modular superhydrophobic chips for reconfigurable assembly and self-propelled droplet manipulation

Natural creatures that enables controllable liquid transport provides the inspiration for developing novel microfluidic devices by engineering functional surfaces with superwettability. However, towards microfluidic applications, the strict requirements of sophisticated droplet manipulation make it challenging to reach this end. In this work, we report a conceptually new self-propelled droplet manipulation strategy based on reconfigurable superhydrophobic chips. The modular droplet chip (MDC) is developed by laser embossing a series of superhydrophobic structures on elastomer jigsaws that act as functional units. MDC is potable since only gravity is used as the driving force for dynamic manipulation of liquid droplets, including droplets transporting, splitting, merging and bouncing without mass loss. The MDC demonstrated reasonable anti-cross-contamination property due to the water repellence of the superhydrophobicity. Modular assembly of MDC enables different chip functions including solution dilution, SERS detection, cell labeling and chemical synthesis. As a miniature and portable experimental platform, the MDC is promising for next-generation lab-on-a-chip systems.

Accomplice Manipulation of the Deferred Acceptance Algorithm

The deferred acceptance algorithm is an elegant solution to the stable matching problem that guarantees optimality and truthfulness for one side of the market. Despite these desirable guarantees, it is susceptible to strategic misreporting of preferences by the agents on the other side. We study a novel model of strategic behavior under the deferred acceptance algorithm: manipulation through an accomplice. Here, an agent on the proposed-to side (say, a woman) partners with an agent on the proposing side---an accomplice---to manipulate on her behalf (possibly at the expense of worsening his match). We show that the optimal manipulation strategy for an accomplice comprises of promoting exactly one woman in his true list (i.e., an inconspicuous manipulation). This structural result immediately gives a polynomial-time algorithm for computing an optimal accomplice manipulation. We also study the conditions under which the manipulated matching is stable with respect to the true preferences. Our experimental results show that accomplice manipulation outperforms self manipulation both in terms of the frequency of occurrence as well as the quality of matched partners.

Serine-ubiquitination regulates Golgi morphology and the secretory pathway upon Legionella infection

SidE family of Legionella effectors catalyze non-canonical phosphoribosyl-linked ubiquitination (PR-ubiquitination) of host proteins during bacterial infection. SdeA localizes predominantly to ER and partially to the Golgi apparatus, and mediates serine ubiquitination of multiple ER and Golgi proteins. Here we show that SdeA causes disruption of Golgi integrity due to its ubiquitin ligase activity. The Golgi linking proteins GRASP55 and GRASP65 are PR-ubiquitinated on multiple serine residues, thus preventing their ability to cluster and form oligomeric structures. In addition, we found that the functional consequence of Golgi disruption is not linked to the recruitment of Golgi membranes to the growing Legionella-containing vacuoles. Instead, it affects the host secretory pathway. Taken together, our study sheds light on the Golgi manipulation strategy by which Legionella hijacks the secretory pathway and promotes bacterial infection.

Ultrafast and long-range self-transport of droplets on multi-bioinspired surface with periodic gradient structure

Droplet self-transport is crucial in various fields ranging from physics to biochemistry. Despite extensive progress, existing systems for droplet self-transport still perform at low transport velocity or limited transport range. Here, a multi-bioinspired surface comprising two-dimensional gradient structures is proposed innovatively, which integrates the heterogeneous wettability with the shape gradient morphology. Droplet transport behaviors are systematically investigated from experiment, theory, and simulation. The fabricated structure achieves the ultrafast (over ~ 450 mm/s) and long-range (over ~ 200 mm) self-transport of droplets. Moreover, the fantastic scalability of this structure enables it to pump numerous multi-scale droplets from one site to the preset region with ultralow loss. Drawing inspirations, two systems have been designed to complete complex tasks on open surface. This work provides a reliable droplet manipulation strategy for various applications, such as water collection, microfluidics, and biomedicine, etc.

COMMUNICATIVE TACTICS MANIFESTING MANIPULATION STRATEGY IN ENGLISH DETECTIVE DISCOURSE

The article reports on the communicative strategy of manipulation and the communicative tactics that manifest it. The samples for the analysis have been taken from English detective discourse. The object of the study is the personages’ speech: the detective’s interrogation of witnesses and suspects. The scope of the study is the communicative tactics applied by the police officers to manipulate witnesses and suspects into revealing the truth about the murder. The purpose is cognitive and pragmatic analysis of the communicative tactics applied by the police officers to manipulate the witnesses and suspects. The investigation is based on the general and special linguistic methods: synthesis and analysis, method of observation, descriptive method, pragmatic and linguistic method, cognitive method, analysis of contextual interpretation. The cognitive and pragmatic analysis of the strategic plan of the police officer, the personage of the detective discourse, has resulted in our own classification of communicative tactics and strategies applied by the police officer during the interrogation of witnesses and suspects. It has been established that one of the major communicative strategies used by the police officer is manipulation. Manipulation is realized by the following communicative tactics: provocation, warning, menace, blackmail, persuasion, flattery. Each of these tactics is manifested by certain lexical, morphological and syntactic means of the English language. The perspective for further research is seen in the comprehensive study of the linguistic mechanisms of manipulative impact on the recipient in fiction.

A dual-arm manipulation strategy using position/force errors and Kalman filter

This paper presents a new coordination manipulation strategy for a custom-made dual-arm robot. With master and slave coordination infrastructure, both spatial relation and sense of touch are considered to hold an object stably. Given the known trajectory of the master arm, the slave arm fuses position and force commands by using the Kalman filter to yield optimal compensation amounts. The proposed strategy has been experimentally evaluated, and the results confirm that it was capable of dealing with fragile and flexible objects. In addition, the influence of the loop time of the digital controller on force control for this task was also investigated in mathematical and simulated ways. Furthermore, a series of experiments were designed to explore the effects that have influences on errors in force control. The main factors that affect force control error were analyzed.