Collaborative problem solving (CPS) is considered as one of the core competencies of the 21st century. Collaborative simulations which allow multiple students to participate in CPS activities in a ...shared simulation session are now increasingly applied to better facilitate these activities. However, the literature has shown that students' collaboration often does not lead to an effective solution to problems. Guided by the PISA CPS framework, this study thus aimed to analyze students’ collaboration patterns and problem solving strategies in solving a physics problem, and to identify significant patterns which may lead to a successful or unsuccessful outcome. Multiple data sources including group discussions, problem solving activities in a collaborative simulation, and open-ended questionnaire feedback from 30 high school students were analyzed using the lag sequential analysis technique. It was found that collaborative simulation has the potential to help students situate their discussion in a joint concrete problem space, facilitating their formation of a path to solve the problem. More importantly, the results showed significant differences between the successful and unsuccessful groups in terms of their collaboration patterns and problem solving strategies. A considerable portion of the students could only apply an intuitive trial-and-error strategy, and failed to solve the problem in the end. These students showed an inability to monitor and analyze the problem solving process, and were unable to transform their discussion into an executable plan to solve the problem. Those students who applied analytical reasoning strategies were more likely to achieve a successful problem solving outcome. The implications for educational practice are discussed, and the directions for future studies addressed.
•This study analyzed collaborative problem solving activities in a collaborative simulation context with LSA techniques.•Significant differences in collaboration problem solving patterns were detected between successful and unsuccessful groups.•A considerable portion of the students showed an inability to monitor and analyze the problem solving process.•These students were unable to transform their discussion into an executable plan to solve the problem.•Those students who applied analytical reasoning strategies were more likely to achieve a successful problem solving outcome.
Electrical impedance tomography (EIT), a noninvasive and radiation-free medical imaging technique, has been used for continuous real-time regional lung aeration. However, adhesive electrodes could ...cause discomfort and increase the risk of skin injury during prolonged measurement. Additionally, the conductive gel between the electrodes and skin could evaporate in long-term usage and deteriorate the signal quality. To address these issues, in this work, textile electrodes integrated with a clothing belt are proposed to achieve EIT lung imaging along with a custom portable EIT system. The simulation and experimental results have verified the validity of the proposed portable EIT system. Furthermore, the imaging results of using the proposed textile electrodes were compared with commercial electrocardiogram electrodes to evaluate their performance.
The objective of this paper is to propose a modularized bidirectional single-phase grid-connected inverter (BGI) with constant-frequency asynchronous sigma-delta modulation (CF-ASDM) control for the ...renewable energy (RE)-supplied dc power system. The proposed BGI can be operated either in the inverter mode (IM) or rectified mode (RM); both are necessary features for the RE-supplied dc power system. By comparing to the conventional ASDM with variable switching frequency, the proposed CF-ASDM can simplify the filter design and can reduce the computational burden of the digital signal processor while maintaining the merit of quick dynamic response. Moreover, the proposed BGI has a redundant central controller which can increase the system reliability. The major contribution of this paper includes developing the modularized BGI with CF-ASDM control scheme for IM and RM operations thoroughly and applying it to the RE-supplied dc power system successfully. In this paper, the mathematical equations to achieve the constant switching frequency operation for the CF-ASDM will be derived. Computer simulations and hardware experiments are shown to verify the performance of the proposed modularized BGI with CF-ASDM control.
Idiopathic mesenteric phlebosclerosis is a rare condition with unclear pathogenesis. This study aimed to investigate the clinical features, diagnostic modalities, treatments, and outcomes of ...idiopathic mesenteric phlebosclerosis patients in Taiwan.
Idiopathic mesenteric phlebosclerosis patients diagnosed by the typical characteristic of tree-like mesenteric venous calcifications on plain abdominal radiography or computed tomography between January 1992 and July 2021 were retrospectively analyzed.
Totally, 36 idiopathic mesenteric phlebosclerosis patients were enrolled (50% females; mean age, 61.6 years). Among the included patients, 26 (72.2%) and 10 (27.7%) were symptomatic and asymptomatic, respectively. Abdominal pain (61.1%) accounted for the majority of all symptoms, followed by fever, diarrhea, and bloody stools. Our results showed that 83.3% of patients had at least 1 risk factor, whereas 16.6% of patients had none. Moreover, among the included patients, 36.1%, 44.4%, 50.0%, 38.8%, and 8.3% had cardiovascular disease, chronic renal disease, cancer, chronic liver disease, and diabetes mellitus, respectively. Our findings showed 94.4% of patients were diagnosed via abdominal computed tomography and plain abdominal radiography, whereas 5.6% of patients were diagnosed via plain abdominal radiography. The ascending colon was the most commonly involved site (100%). Our findings showed that 91.6% of patients experienced good recovery after conservative treatment, except for the 3 who died of sepsis and respiratory failure. By contrast, 8.3% of idiopathic mesenteric phlebosclerosis patients underwent colectomy. The average follow-up duration was 62.5 months.
Idiopathic mesenteric phlebosclerosis remains a rare disease in Taiwan. Plain abdominal radiography and computed tomography can be utilized for establishing a definite diagnosis. Conservative treatment is usually adequate for most patients, with surgical treatment only indicated for severe cases.
Computer vision has been applied in many fields recently to extract useful information from images. One such application is the monitoring of various aquaculture species to increase production. By ...monitoring the locations and quantities of the white shrimp, the aquaculture farmers could deliver the feed more precisely. Besides, the information about the length of the white shrimp could make the farmers estimate the delivery time accurately. Usually, to ensure the accuracy of computer vision, a relatively high-quality picture is required. However, the quality of underwater photography is easily influenced by the light, color, and turbidity of the medium. Compared to optical photos, the imaging mechanism of ultrasound is less affected by these effects. This study proposes an innovative white shrimp monitoring system that combines ultrasound imaging technology with YOLOv4. The database of the shrimps' ultrasound images was built by imaging the different parts of the shrimp from various viewing angles with a linear ultrasonic probe. Four models using training data of different scenarios were successfully trained to recognize the locations of the shrimps from the ultrasound images. Among these models, the best was the one trained with 650 one-shrimp and 1080 two-shrimp practical transverse ultrasound images and 6500 images from data augmentation. Unlike optical pictures, ultrasound images are cross-sectional images that slice across certain parts of the shrimps. Therefore, a bi-directional scanning approach was adopted in this study. The ultrasound probe was carried by a two-axis motor to capture the images from two orthogonal viewing angles within a 12.69 cm × 12.69 cm region of interest. After 260 images were captured, the locations of the shrimps in each image were recognized and the centers of the bounding boxes were marked. To determine the number of shrimps, a voting method was developed based on the spectral clustering algorithm to group the marked coordinates. Finally, the number, lengths, and positions of the shrimps were reported. To evaluate the accuracy of the proposed monitoring system, 100 shrimps with 40 different layouts containing 1 to 4 shrimps were tested. The averaged quantity error, position error, and length error were 97.3%, 0.97 cm, and 8.99%, respectively. The standard deviation of the position error and the length error were 0.55 cm and 5.42%, respectively. The results demonstrated that the proposed system can provide useful information on shrimps and is feasible for shrimp farming applications.
Background and Aim
Meckel's diverticulum (MD) is a common congenital abnormality of the gastrointestinal (GI) tract. Although a few patients with MD present symptoms, preoperative diagnosis of MD is ...a clinical challenge because of its endoscopic inaccessibility. The aim of the present study was to investigate patients with MD diagnosed by double‐balloon enteroscopy (DBE) in Taiwan.
Methods
We conducted a retrospective study in a tertiary referral center in middle Taiwan. The clinical characteristics, endoscopic features, histopathological findings, treatment methods, and outcomes of patients with MD diagnosed by DBE were analyzed.
Results
A total of 14 male patients with MD diagnosed by DBE were enrolled. The mean age of all patients was 32.3 years. GI bleeding (78.6%) accounted for the major indication of DBE, followed by abdominal pain and Crohn's disease follow‐up. The mean distance between the ileocecal valve and MD was 68.9 cm. The average length of 12 patients with surgically resected MD was 5.2 cm. The diagnostic yields of the other modalities excepting DBE are as follows: capsule endoscopy, 50%; Meckel's scan, 11.1%; computed tomography, 16.7%; small bowel series, 0%; and angiography, 33.3%. MD presented as a large ostium in 13 patients (92.9%), a small ostium in 1 patient (7.1%), and bleeding signs in 10 patients (71.4%). Twelve patients (85.7%) underwent surgical treatment and 2 patients (14.3%) received conservative treatment. Heterotopic gastric tissue was identified in 4 patients (28.6%).
Conclusion
The present study showed that DBE is a more powerful modality in detecting MD than the other conventional modalities in Taiwan.
Meckel's diverticulum (MD) is a rare cause of small bowel bleeding in adult patients. Furthermore, it is a clinical challenge because of its endoscopic inaccessibility. Double‐balloon enteroscopy is a more powerful modality in diagnosing MD than other conventional modalities.
Glucose, which plays a central role in providing energy for metabolism, is primarily stored as glycogen. The synthesis and degradation of glycogen are mainly initialized by glycogen synthase (GS) and ...glycogen phosphorylase (GP), respectively. The present study aimed to examine the glycogen metabolism in fish liver and gills during acute exposure to seawater. In tilapia (Oreochromis mossambicus) gill, GP, GS and glycogen were immunocytochemically colocalized in a specific group of glycogen-rich (GR) cells, which are adjacent to the gill's main ionocytes, mitochondrion-rich (MR) cells. Na+/K+-ATPase activity in the gills, protein expression and/or activity of GP and GS and the glycogen content of the gills and liver were examined in tilapia after their acute transfer from freshwater (FW) to 25 per thousand seawater (SW). Gill Na+/K+-ATPase activity rapidly increased immediately after SW transfer. Glycogen content in both the gills and liver were significantly depleted after SW transfer, but the depletion occurred earlier in gills than in the liver. Gill GP activity and protein expression were upregulated 1-3 h post-transfer and eventually recovered to the normal level as determined in the control group. At the same time, GS protein expression was downregulated. Similar changes in liver GP and GS protein expression were also observed but they occurred later at 6-12 h post-transfer. In conclusion, GR cells are initially stimulated to provide prompt energy for neighboring MR cells that trigger ion-secretion mechanisms. Several hours later, the liver begins to degrade its glycogen stores for the subsequent energy supply.
Three strains of Vibrio parahaemolyticus (690, BCRC 13023, and BCRC 13025), involved in foodborne outbreaks in Taiwan, were subjected to acid adaptation at pH 5.5 for 90 min. The effects of acid ...adaptation on the tolerance of V. parahaemolyticus to various environmental stresses, including heat (47°C), cold (4°C and -20°C), ethanol (8%), high salt (20% NaCl), and hydrogen peroxide (20 ppm) were examined. Results showed that acid adaptation increased the thermal tolerance of the three test strains of V. parahaemolyticus, while it did not affect their cold tolerance. Acid adaptation also increased the ethanol tolerance in V. parahaemolyticus 690 and BCRC 13025, but not in BCRC 13023. Differences in the tolerance to high salts were noted among the three strains after prior acid adaptation. However, these acid-adapted V. parahaemolyticus strains were more susceptible to hydrogen peroxide than their nonadapted controls. These findings demonstrated that acid adaption responses of V. parahaemolyticus varied among strains and types of stress challenge.
Reaction of Mo(CO)
6 with excess
N,
N′-di(3-methoxyphenyl)formamidine (HDmAniF) in
o-dichlorobenzene afforded the yellow complex Mo
2(DmAniF)
4,
1. The structure of
1 reveals that the ligands bridge ...the two metal centers through the two nitrogen atoms, forming two
s-
cis,
s-
trans and two
s-
trans,
s-
trans conformations. Reaction of
1 with Me
3OBF
4 in CH
3CN gave
cis-Mo
2(DmAniF)
2(CH
3CN)
4BF
4
2,
2, which crystallized in two different forms. The first form,
2·CH
2Cl
2·CH
3CN,
2a, showing one
BF
4
-
anion coordinating to the axial positions of the Mo–Mo bond Mo⋯F
=
2.685(4) Å, contains two
cis DmAniF
− ligands which adopt the same
s-
cis,
s-
trans conformation. The other form,
2·0.5CH
2Cl
2
·
0.5CH
3CN,
2b, involves two independent molecules. While one Mo–Mo
=
2.1432(8) Å of the two molecules shows axial interaction by CH
3CN Mo⋯N
=
2.692(8) Å and the two
cis DmAniF
− ligands adopt the same
s-
cis,
s-
trans conformation, the other one Mo-Mo
=
2.1317(9)
Å shows no axial interaction and the two
cis DmAniF
− ligands adopt different conformations, which are
s-
cis,
s-
trans and
s-
cis,
s-
cis, respectively. The Mo–Mo distance of
2a, 2.1281(6)
Å, is the shortest among the compounds having Mo
2(μ
2-L)
2(CH
3CN)
4 core, where L is the anionic, cationic or neutral form of a formamidine ligand. Reaction of
2 with NaOCH
3 in CH
3OH produced the tetranuclear complex
cis-Mo
2(DmAniF)
2
2(μ-OCH
3)
4,
3. The molecule of
3 bears four bridging CH
3O
− groups that link two quadruply bonded moieties and the ligands adopts the
s-
trans,
s-
trans conformation.
The blast furnace is crucial for iron production in industries, with its campaign life directly impacting iron-producing costs. One significant factor affecting its lifespan is the thickness of the ...carbon brick which is closely related to the hearth temperature. However, the intensive smelting leads to abnormally high temperatures that erode the carbon bricks and shorten the blast furnace's lifespan. We proposed a machine-learning (ML) model for predicting the hearth temperature to solve this issue. In this study, a Long Short-Term Memory (LSTM) model was trained to predict the hearth temperature. The training data set originated from the operation data of one of the blast furnaces for 2761 days each of which contained 1470 features. After discussions with CSC experts, the feature number was reduced from 1470 to 360 by removing irrelevant features. Next, the top 150, 100, and 50 features related to the hearth temperature were found using the Pearson correlation coefficient. Three LSTM models were trained using three feature subsets to optimize the feature number. Furthermore, different combinations of input and output lengths were tested to optimize the model. The input lengths were 15, 30, and 45 days, and the output lengths were 1, 3, and 5 days. The last 480 days were separated from the training dataset to examine the long-term prediction of the proposed LSTM model. Since the working conditions, raw materials, and operation protocols were mutated during operation, the frequency of updating the prediction model was investigated to improve the long-term prediction accuracy. The dataset with 150 features achieved the best performance with a mean squared error (MSE) of 0.0829. For the optimal configuration, the previous 30 days' features were used to predict the temperature for the next 3 days, updated every three days. This configuration achieved the lowest MSE of 0.00939, much better than the average MSE of all groups of 0.0214. The best combination of the dataset and machine learning (ML) model was selected as a result of this study.
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