Misconceptions on force and gravity among high school students

The goal of this study is to determine prevalent or dominant misconceptions on force and gravity among high school students. A survey instrument consisting of 12 qualitative questions requiring both answers and written explanations was used to gather students’ ideas and beliefs in situations involving force and gravity. Furthermore, it examined whether the proportion of students having misconceptions per question are correlated with gender and the type of school Physics background. The results show that the respondents have misconceptions that are similar to the misconceptions found in previous research. The number of misconceptions and the proportion of students having misconceptions per question are not correlated with gender. They are, however, correlated with the amount of Physics instruction. Both the number of misconceptions and the proportion of students having misconceptions diminish as the school Physics background progresses from Middle School Science to High School Physical Science, and finally to High School Physics

Moyal deformation of the classical arrival time

The quantum time of arrival (TOA) problem requires a statistics of measured arrival times given only a particle's initial state. Following the standard framework of quantum theory, the problem translates into finding an appropriate quantum image of the classical arrival time $\mathcal{T}_C(q,p)$, usually in operator form $\hat{\mathrm{T}}$. In this paper, we consider the problem anew within the phase space formulation of quantum mechanics. The resulting quantum image is a real-valued and time-reversal symmetric function $\mathcal{T}_M(q,p)$ in formal series of $\hbar^2$ with the classical arrival time as the leading term. It is obtained from the Moyal bracket relation with the system Hamiltonian and is hence interpreted as a Moyal deformation of the classical TOA. Finally, we show that $\mathcal{T}_M(q,p)$ is isomorphic to the rigged Hilbert space TOA operator constructed recently in [Eur. Phys. J. Plus \textbf{138}, 153 (2023)] independent of canonical quantization

Fishes of Laguna de Bay in the Philippines: Status and research gaps for conservation using FishBase

Abstract only.FishBase is the world s premier database on fishes with key information on more than 27,800 species. A review of FishBase indicates that the fish fauna of Laguna de Bay consists of 31 species belonging to 18 families. Three species are endemic to the Philippines, 12 species were introduced in the bay and the remaining 16 species are all native species. FishBase contains a wide range of biological and ecological parameters needed for stock assessment and modeling, as well as information including food items, feeding habits, diet composition and estimated trophic levels of the species. The latter ranged from 2-4.3 and the following functional trophic groups were identified: (a) pure herbivores (troph level between 2.0-2.19) feeding on diatoms, detritus, algae and phytoplankton; (b) omnivores (troph level between 2.2 - 3.4) feeding on a wide variety of prey, such as, algae, detritus, amphipods, ostracods, insects, planktonic invertebrates, lobsters and mollusks; and (c) carnivores (troph level between 3.7 - 4.3) with preference for shrimps, bony fish, insects, crustaceans and mollusks. Documentation on the status and biological information of the lake s resource and the need to identify research gaps using FishBase can serve as basis for the formulation of research planning and a management and conservation scheme. In the context of worldwide trends towards ecosystem-based management, the value of databases, as in FishBase, in national planning is increasingly important

Evaluating the Performance of Rice Genotypes for Improving Yield and Adaptability Under Direct Seeded Aerobic Cultivation Conditions

With the changing climatic conditions and reducing labor-water availability, the potential contribution of aerobic rice varieties and cultivation system to develop a sustainable rice based agri-food system has never been more important than today. Keeping in mind the goal of identifying high-yielding aerobic rice varieties for wider adaptation, a set of aerobic rice breeding lines were developed and evaluated for grain yield, plant height, and days to 50% flowering in 23 experiments conducted across different location in Philippines, India, Bangladesh, Nepal, and Lao-PDR between 2014 and 2017 in both wet and dry seasons. The heritability for grain yield ranged from 0.52 to 0.90. The season-wise two-stage analysis indicated significant genotype x location interaction for yield under aerobic conditions in both wet and dry seasons. The genotype × season × location interaction for yield was non-significant in both seasons indicating that across seasons the genotypes at each location did not show variability in the grain yield performance. Mean grain yield of the studied genotypes across different locations/seasons ranged from 2,085 to 6,433 Kg ha−1. The best-fit model for yield stability with low AIC value (542.6) was AMMI(1) model. The identified stable genotypes; IR 92521-143-2-2-1, IR 97048-10-1-1-3, IR 91326-7-13-1-1, IR 91326-20-2-1-4, and IR 91328-43-6-2-1 may serve as novel breeding material for varietal development under aerobic system of rice cultivation. High yield and stable performance of promising breeding lines may be due to presence of the earlier identified QTLs including grain yield under drought, grain yield under aerobic conditions, nutrient uptake, anaerobic germination, adaptability under direct seeded conditions, and tolerance to biotic stress resistance such as qDTY2.1, qDTY3.1, qDTY12.1, qNR5.1, AG9.1, qEVV9.1, qRHD1.1, qRHD5.1, qRHD8.1qEMM1.1, qGY6.1, BPH3, BPH17, GM4, xa4, Xa21, Pita, and Pita2. The frequency of xa4 gene was highest followed by qAG9.1, GM4, qDTY3.1, qDTY2.1, qGY6.1, and qDTY12.1

Review of nanomaterials in dentistry: interactions with the oral microenvironment, clinical applications, hazards, and benefits.

Interest in the use of engineered nanomaterials (ENMs) as either nanomedicines or dental materials/devices in clinical dentistry is growing. This review aims to detail the ultrafine structure, chemical composition, and reactivity of dental tissues in the context of interactions with ENMs, including the saliva, pellicle layer, and oral biofilm; then describes the applications of ENMs in dentistry in context with beneficial clinical outcomes versus potential risks. The flow rate and quality of saliva are likely to influence the behavior of ENMs in the oral cavity, but how the protein corona formed on the ENMs will alter bioavailability, or interact with the structure and proteins of the pellicle layer, as well as microbes in the biofilm, remains unclear. The tooth enamel is a dense crystalline structure that is likely to act as a barrier to ENM penetration, but underlying dentinal tubules are not. Consequently, ENMs may be used to strengthen dentine or regenerate pulp tissue. ENMs have dental applications as antibacterials for infection control, as nanofillers to improve the mechanical and bioactive properties of restoration materials, and as novel coatings on dental implants. Dentifrices and some related personal care products are already available for oral health applications. Overall, the clinical benefits generally outweigh the hazards of using ENMs in the oral cavity, and the latter should not prevent the responsible innovation of nanotechnology in dentistry. However, the clinical safety regulations for dental materials have not been specifically updated for ENMs, and some guidance on occupational health for practitioners is also needed. Knowledge gaps for future research include the formation of protein corona in the oral cavity, ENM diffusion through clinically relevant biofilms, and mechanistic investigations on how ENMs strengthen the tooth structure

Seaweeds preferred by herbivorous fishes

Marine macrobenthic algae (or seaweeds), epiphytic microalgae, and other aquatic plants constitute the main food items of marine herbivorous fishes. About 5% of all fish species are herbivorous; only 30% of these are marine, most of them living in coral reefs. An analysis was performed on all the seaweeds that formed part of the natural diet of these fishes, based on information contained in FishBase (http://www.fishbase.org). The results showed that many coral-reef-associated marine herbivorous fishes, such as the families Blennidae, Kyphosidae and Siganidae, fed selectively on filamentous and turf fleshy seaweeds, which they prefer over calcareous coralline and encrusting species. In particular, Chlorophyceae of the genera Cladophora, Enteromorpha and Ulva were preferred by Scartichthys viridis (Blennidae), Girella spp. (Kyphosidae), Sarpa salpa (Sparidae), and Phaeophyceae in the genera Sargassum and Dictyota were preferred by Kyphosus spp. (Kyphosidae) and Siganus spp. (Siganidae). A web-based tool was developed to provide information on plants (algae, seagrasses, terrestrial plants and fruits) preferred as food by herbivorous fishes (http://www.incofish.org/herbitool.php). The tool is intended to assist aquaculturists, conservationists and ecosystem-based fisheries managers

`Barrier traversal time' and `quantum tunneling time' for arbitrary potential barriers

We demonstrate how an operator-based theory of quantum time-of-arrival (TOA) reconciles the seemingly conflicting reports on the measured tunneling times. This is done by defining the barrier traversal time as the difference of the expectation values of the corresponding TOA-operators in the presence and absence of the barrier. We show that for an arbitrarily shaped potential barrier, there exists three traversal time regimes corresponding to full-tunneling, partial-tunneling, and \non-tunneling processes, which are determined by the relation between the the support of the incident wavepacket's momentum distribution $\tilde{\psi}(k)$, and shape of the barrier. The full-tunneling process occurs when the support of $\tilde{\psi}(k)$ is below the minimum height of the barrier, resulting to an instantaneous tunneling time. The partial-tunneling process occurs when the support or a segment of the support of $\tilde{\psi}(k)$ lies between the minimum and maximum height of the barrier. For this case, the particle does not "fully" tunnel through the entire barrier system resulting to a non-zero traversal time. The non-tunneling regime occurs when the support of $\tilde{\psi}(k)$ is above the maximum height of the barrier system, leading to a classical above-barrier traversal time. We argue that the zero and non-zero tunneling times measured in different attoclock experiments correspond to the full-tunneling and partial-tunneling processes, respectively

The experiences of adaptation to relocation among institutionalized elderly using personal resource

The experiences of adaptation to relocation of institutionalized elderly using personal resources are investigated. This study aims to understand how the elderly adapt in an institution or nursing home with only the available personal resources that they have. It then study aims to identify the different kinds of experiences the elderly have when it comes to relocation and adaptation, as well as the resources used and how it was used in adapting to the new environment. To investigate the problem, eight elderly from one institution were interviewed. Results show that the experiences of the elderly in adapting in the institution are: maintaining health, fitting in, and keeping themselves productively occupied. Resources used in adapting were found to be personal characteristics and provided support. Lastly, results also found out that practicing values and utilizing provided help were the ways in which the elderly uses their resources. The elderly uses, then, these resources as a way of optimizing their capabilities and compensating for their disabilities