Jurnal Fisika Unand
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Datos y reflexiones para la evaluación de la secuencia de actividades ¿AQUÍ SOLO HAY MATOJOS?
No full textLo expuesto en el documento se refiere a la evaluación que se ha llevado a cabo en las distintas implementaciones de una secuencia de enseñanza-aprendizaje (SEA) consistente en una propuesta de itinerario didáctico producto de la Investigación de Diseño (Design-Based Research o DBR).
Los datos que se incluyen en este documento, fruto de la recogida de información a través de instrumentos de distinta naturaleza a lo largo de 11 iteraciones que han tenido lugar a lo largo del proceso de diseño, son un adelanto de resultados de la implementación de la SEA y una reflexión general sobre los mismos. Los análisis y descripciones detalladas son objeto de otras publicaciones y no se incluyen en el presente documento.
Han sido objeto de evaluación y recogida de información, por un lado la evolución del conocimiento científico del alumnado en torno a las temáticas interrelacionadas de la desertificación, la biodiversidad y los ecosistemas; y, por otro lado, la adecuación, viabilidad e idoneidad de la propia secuencia y su proceso de diseño, así como la detección de incidencias y aspectos susceptibles de mejora de cara a sucesivas implementaciones.
En las diferentes iteraciones se han ido evaluando distintos aspectos con diferentes instrumentos orientados a una evaluación competencial y contextualizada, a través del uso de conceptos y procedimientos para entender e interpretar su entorno inmediato, reconociendo los elementos que lo conforman y algunas de las relaciones entre los mismos
Consumer research domains in the sharing economy: an organizing and categorizing review with research implications
No full textThis article presents a comprehensive systematic literature review (SLR) that organises and categorises consumer behaviour research in the context of the sharing economy. To structure the review, our review employs Hoyer et al.‘s (2017) well recognised consumer behaviour model, encompassing four dimensions and fourteen domains. Through a rigorous, transparent, and reproducible selection process, we identified 459 articles that delve into consumer behaviour within this field. Following a framework-based SLR approach, for each article, we meticulously examined its theoretical approach and results, including harmonious, contradictory, and inconclusive ones, assigning their contributions to the different dimensions and domains of consumer research. In addition, we highlight dimensions and domains that require further investigation, outlining directions, and gaps for future research. This systematic approach provides a comprehensive overview and insightful analysis of consumer behaviour in the sharing economy, facilitating a deeper understanding and offering valuable insights for scholars and practitioners in this field
Increasing the sustainability of photoautotrophic microalgae production by minimising freshwater requirements
No full textThere are now several companies that are producing microalgae such as Arthrospira platensis, Chlorella vulgaris, and Dunaliella salina, among others. They are cultivated mainly in large-scale raceway and tubular photobioreactors. Microalgae production represents a sustainable alternative to conventional biomass production. Microalgae can be used to manufacture agricultural products, animal feed, food and other commercial products. The water requirements for cultivating microalgae are significant, exceeding 1 m3·kg−1. This value varies depending on the production strategy. One of the main reasons for water loss is evaporation, which is influenced by the photobioreactor location, the season, and the operating conditions. Efforts are being made to reduce water requirements and make microalgae production economically viable and more environmentally friendly. Several strategies are being investigated for reducing freshwater use in microalgae cultivation; these include reusing the culture medium and producing microalgae using seawater or wastewater. Such strategies not only reduce water consumption, but also reduce nutrient consumption and costs while increasing sustainability
Evaluation of teaching practices in the Degree in Primary Education from the student’s perspective
No full textEn el marco de la formación inicial de docentes, el conocimiento de las acciones pedagógicas del profesorado universitario y su repercusión en la construcción de identidades profesionales resulta clave para mejorar dicha formación y posibilitar la transformación de la educación ante los desafíos globales del siglo XXI. En este contexto, el presente estudio tiene como objetivo general evaluar las prácticas docentes universitarias desarrolladas en el marco de las asignaturas del área de Didáctica de las Ciencias Sociales del Grado en Educación Primaria, a partir de las opiniones del alumnado sobre los procesos formativos y de evaluación implementados en estas materias. MÉTODO: A través de un diseño metodológico cuantitativo no experimental, con recopilación de información mediante cuestionario y siguiendo un muestreo no probabilístico por conveniencia, se analizan las opiniones de 1045 (n=1045) estudiantes de seis universidades españolas. En el análisis de datos, realizado con el programa estadístico SPSS v28.0, se ha atendido a los estadísticos descriptivos y frecuencias, a las correlaciones entre los ítems y a un análisis inferencial con prueba de t de student para las variables dicotómicas (sexo y edad) y ANOVA para la variable categórica sobre experiencia previa. RESULTADOS: Los resultados muestran que los participantes consideran como mejor modelo para su desarrollo profesional aquellas propuestas formativas con mayor carácter crítico, reflexivo y transformador, sin embargo, cuestionan que la formación recibida contribuya a construir su identidad docente y que el profesorado universitario pueda ser un referente que imitar en su futuro profesional. DISCUSIÓN: Se evidencia, pues, la necesidad de mejorar las estrategias docentes del profesorado universitario de esta área de conocimiento y de implementar, en mayor medida, acciones didácticas que contribuyan a reflexionar, junto al alumnado, sobre los obstáculos que impiden una adecuada formación a partir de los modelos docentes que se ofrecen. In the context of initial teacher training, teachers’ knowledge of pedagogical
actions and their impact on the construction of models and teaching identities in students is key to enable
the transformation of education in the face of the global challenges of the 21st century. In this context, this
study presents as a general objective to know the vision of the students of the Degree in Primary Education
about the formative and evaluative process received in the subjects on Didactics of the Social Sciences that
they have taken during their university studies. METHOD: To respond to this objective, it has been used a
non-experimental quantitative research design. The information has been collected through a questionnaire,
in which 1045 (n=1045) students from six Spanish universities have participated. Sampling has been nonprobabilistic for convenience. In the analysis of the data, carried out with the statistical program SPSS v28.0,
the descriptive statistics and frequencies, the correlations between the items and the inferential analysis
with Student t-test for the dichotomous variables (sex and age), and ANOVA for the categorical variable
of previous experience, were considered. RESULTS: The main result reflects that the teachers in training consider that those training proposals that have a more critical, reflective, and transformative approach are
the best model for their own professional development. However, the participants do not consider in all cases
that the training received has contributed to building their teaching identity and that teachers are a reference
to imitate in their professional future as teachers. DISCUSSION: Consequently, it´s necessary improving
university teaching practices in this area and to implement training actions that contribute to reflect, together
with the students, about the obstacles that prevent adequate training on teaching models offered
Modelling the effect of a white marble gravel mulch on the energy balance inside a Mediterranean naturally ventilated greenhouse with a tomato crop
No full textThe use of soil mulching is an agricultural technique used for hundreds of years with the objective of reducing soil evaporation and heat loss at night. The reflection of solar radiation that reaches the ground depend on the type of mulching, affecting both energy balances in air and on plants. In winter, when the aim is to increase the temperature of the greenhouse, black mulches are suitable while in summer white mulches are used to reduce heat absorption in the soil. However, the use of plastic mulches with high reflective power can produce negative effects on pollinating insects or cause burns on fruits or leaves. In order to reduce the solar radiation absorbed by the soil and avoid the reflection of direct radiation, in September 2022 a white marble gravel mulch was installed in the western sector of a multispan greenhouse in Almería (Spain). In the east sector, a black polypropylene plastic mulching was maintained. The increase of solar radiation reflection, from the 11% produced with the plastic black mulching to the 44% obtained with the marble mulching, allowed reducing a 10% the net radiation at 2 m height. As consequence, the PAR radiation was increase at the level of the tomato leaves while maintaining the same temperature of the air and the plants. In this work the different components of the energy balances of greenhouse and plants were analyzed. The model used allows predicting the air temperature for a week within the sectors with white marble and black plastic mulching with an average error of 10% and R2>0.91. The model also allows us to predict that the use of marble mulching would permit to eliminate the whitewashing of the roof, increasing inside radiation by 38%, maintaining the same temperature as with the black plastic mulching and the cover whitewashing
Positive solutions for a stationary reaction-diffusion-advection model with nonlinear advection term
No full textIn this work, we investigate a stationary reaction–diffusion–advection equation with a nonlinear term in the gradient, which entails several technical challenges in the analysis. By combining the method of sub- and supersolutions with bifurcation theory, we establish results on the existence and multiplicity of positive solutions
Identifikasi Segmen Talamau Menggunakan Kombinasi Data Satelit GGMPlus dan Koreksi SRTM2gravity Berdasarkan Analisis Second Vertical Derivative (SVD)
Full text linkThe existence of the Talamau segment was only identified by the BMKG after the earthquake that occurred on Friday morning 25 February 2022 in Talamau District, West Pasaman Regency. This earthquake had a magnitude of 6.1 Mw with 201 aftershocks. This research aims to determine the characteristics of the fault types of the Talamau segment using the gravity method. The gravity method can describe subsurface geological structures based on differences in rock density known as gravity anomalies. Gravity data is taken from satellite gravity data in the form of GGMplus data and SRTM2gravity topography data. The resulting gravity anomaly value can be used to determine the characteristics of the fault type using Second Vertical Derivative (SVD) analysis. The combination of GGMplus and SRTM2gravity data provides results that can describe the existence of the Talamau segment based on differences in rock density contrast. The existence of the Talamau segment is in a moderate anomalous pattern with the constituent components namely alluvium rock, gravel sand, silt, Talamau mountain rock, inseparable volcanic rock, intrusive rock, and Kuantan formation rock. From the SVD analysis, the characteristics of the fault type of the Talamau segment are also obtained, namely strike-slip faults.
Tinjauan Klimatologis Kejadian Banjir Bandang di Kabupaten Lahat, Sumatera Selatan Tanggal 5 Juli 2023
Full text linkBPBD reported that a flash flood occurred in Lahat Regency due to high rainfall in the early hours of Wednesday, July 5, 2023. This led to an overflow of the Lematang River, causing flooding that submerged roads and parts of residential areas. Therefore, research is essential to understand atmospheric dynamics and review climatological conditions during the flash flood event in Lahat Regency, covering Pulau Pinang District, Lahat District, and Mulak Sebingkai District. This research is expected to serve as a scientific basis for mitigation and adaptation measures against hydrometeorological disasters. Global phenomena such as the Madden–Julian Oscillation (MJO), El Niño Southern Oscillation (ENSO), and monsoon activity have been analyzed. The analysis of local and regional-scale meteorological parameters was conducted using atmospheric reanalysis datasets from JRA-3Q, NCEP/NCAR, and NCICS. Additionally, a climatological review was carried out based on rainfall data from several cooperative rain gauge stations around the affected area, supplemented with GSMaP satellite data. The study indicates that the flash flood was caused by heavy to very heavy rainfall in the surrounding areas. This rainfall resulted from several factors, including the active MJO over the Indian Ocean, wind convergence, and the presence of the Intertropical Convergence Zone (ITCZ) extending along the western part of Sumatra. The presence of a low-pressure area enhanced the potential for convective cloud formation, further intensified by atmospheric moisture levels exceeding 80% at the 850 mb layer, increasing water vapor content in the upper atmosphere. A historical data review shows that, climatologically, the rainfall during the flash flood event represented the highest recorded daily maximum rainfall for July within the observation period, surpassing pentad and decadal averages. The influence of global, regional, and local-scale phenomena contributed to the increased rainfall intensity in the flash flood-affected area.Dinamika atmosfer dan tinjauan kondisi klimatologis selama terjadi banjir bandang di Kabupaten Lahat meliputi Kecamatan Pulau Pinang, Kecamatan Lahat dan Kecamatan Mulak Sebingkai pada tanggal 5 Juli 2023 telah dianalisis. Hujan sangat lebat diduga sebagai pemicu terjadinya banjir bandang. Tinjauan klimatologis dilakukan berdasarkan data curah hujan pada beberapa pos hujan kerjasama di sekitar lokasi kejadian yang diamati oleh Stasiun Klimatologi Sumatera Selatan sebagai Unit Pelaksana Teknis dari BMKG dan data satelit GSMaP, serta data meteorologi dari dataset reanalisis atmosfer JRA-3Q, NCEP/NCAR dan NCICS. Kondisi fenomena global seperti Madden–Julian Oscillation (MJO), El Nino Southern Oscillation (ENSO) dan monsun juga dianalisis. Penelitian ini memperlihatkan bahwa penyebab terjadinya banjir bandang adalah hujan dengan intensitas lebat hingga sangat lebat dari daerah sekitarnya. Hujan ini disebabkan oleh beberapa faktor seperti aktifnya MJO di wilayah Samudera Hindia, adanya belokan dan konvergensi antartropis yang memanjang di sepanjang bagian barat Sumatera akibat daerah bertekanan rendah telah meningkatkan potensi pertumbuhan awan konvektif, ditambah tingkat kelembaban udara di atas 80% pada lapisan 850mb menambah kandungan uap air di atmosfer atas. Setelah ditinjau dari historis data, secara klimatologis hujan pada saat kejadian banjir bandang merupakan curah hujan maksimum harian tertinggi yang pernah terukur selama waktu pengamatan pada bulan Juli setelah dibandingkan terhadap pentad maupun dasarian di pos hujan Gumai Ulu (137 mm), pos hujan Pagar Gunung (125 mm) dan Pajar Bulan (93 mm). Sedangkan curah hujan yang tercatat pada pos hujan Pulau Pinang (26 mm) lebih kecil dari curah hujan maksimum hariannya pada bulan Juli (129 mm). Pengaruh faktor lokal yaitu pegunungan menyebabkan peningkatan curah hujan karena terjadi hujan orografis yang turun pada sisi belakang gunung di wilayah terjadinya banjir bandang
Analisis Ketidakstabilan Lereng Berdasarkan Nilai Suseptibilitas Magnetik (Studi Kasus: Dua Lereng di Nagari Sikucur Tengah, Padang Pariaman)
Full text linkA study has been conducted for slope instability analysis based on magnetic susceptibility values in Nagari Sikucur Tengah, Padang Pariaman. Soil sampling was carried out on two tracks from slopes without vegetation (Path A) and slopes with vegetation (Path B) and one reference point. Measurement of magnetic susceptibility values of samples using the Bartington Susceptibility Meter using two frequencies, namely low frequency (lf) and high frequency (hf). Based on the magnetic susceptibility value at low frequency (κlf), it was obtained that the magnetic minerals that control the reference point samples are ferrimagnetic, while samples from Path A and Path B are ferrimagnetic and paramagnetic, but some samples from Path B are ferrimagnetic. The relationship between the κlf value and the depth at the reference point shows a consistent pattern of decreasing values, while Path A and Path B fluctuate and the κlf value at Path A is much smaller than Path B from the reference point. Based on the frequency-dependent susceptibility value κfd, the sample of Path A is dominated by superparamagnetic domains, indicating that the sample has much smaller grains than the sample of Path B. Both slopes have experienced instability, where the slope of Path A has experienced higher instability than the slope of Path B.Telah dilakukan penelitian untuk analisis ketidakstabilan lereng berdasarkan nilai suseptibilitas magnetik di Nagari Sikucur Tengah, Padang Pariaman. Pengambilan sampel tanah dilakukan pada dua lintasan dari lereng tanpa vegetasi (Lintasan A) dan lereng bervegetasi (Lintasan B) dan satu titik acuan. Pengukuran nilai suseptibilitas magnetik sampel menggunakan alat Bartington Susceptibility Meter dengan menggunakan dua frekuensi yaitu low frequency (lf) dan high frequency (hf). Berdasarkan nilai suseptibilitas magnetik pada low frequency (κlf) diperoleh bahwa mineral magnetik yang mengontrol sampel titik acuan bersifat ferrimagnetik, sedangkan sampel Lintasan A dan Lintasan B bersifat ferrimagnetik dan paramagnetik, tetapi sebagian sampel Lintasan B bersifat ferimagnetik. Hubungan nilai κlf terhadap kedalaman pada titik acuan menunjukkan pola penurunan nilai yang konsisten, sedangkan pada Lintasan A dan Lintasan B mengalami fluktuatif dan nilai κlf pada Lintasan A jauh lebih kecil dibandingkan Lintasan B dari titik acuan. Berdasarkan nilai suseptibilitas bergantung frekuensi κfd sampel Lintasan A didominasi oleh domain superparamagnetik yang mengindikasikan bahwa sampel memiliki butiran yang jauh lebih kecil dibandingkan sampel Lintasan B. Kedua lereng telah mengalami ketidakstabilan, dimana lereng Lintasan A telah mengalami ketidakstabilan lebih tinggi dibandingkan lereng Lintasan B
Analisis Pengaruh Penggunaan Physical Wedge Filter pada Dose Profile dan Percentage Depth Dose Pesawat Radioterapi Clinax-Cx di Rumah Sakit Universitas Andalas
Full text linkA study has been conducted on the effect of using a physical wedge filter on the dose profile and Percentage Depth Dose (PDD) of the CLINAC-CX teletherapy device at Andalas University Hospital. This study aims to determine the shape of the dose profile and PDD curves formed from the use of physical wedges. Measurements were made with variations in photon beam energy (6 MV and 10 MV) and variations in the angle of the physical wedge filter (15°, 30°, 45°, and 60°). Data processing begins by calculating incomplete data from the LINAC using interpolation techniques. The data is then displayed in the form of a curve or graph using Microsoft Excel. The results of the PDD curve measurement showed no significant difference in the curve formed using or without a wedge. The resulting zmax did not differ much from each other, where for a 6 MV beam without a wedge it was 13.8 mm while the average wedge variation was 14.72 mm. The 10 MV beam variation showed a value of 23.4 mm and an average of 24 mm. The dose profile formed is influenced by the use of wedge, the comparison of the smallest and largest symmetry, flatness, and penumbra values. The smallest values at 6 MV irradiation without wedge are respectively 2.1%, 3.1%, 7.1 mm, and 7.3 mm, while the largest with a wedge angle of 60°, 32.4%, 58.3%, 15.8 mm. The wedge factor between 6 MV and 10 MV shows no difference