170 research outputs found
Defining the Competence of Abstract Thinking and Evaluating CS-Students\u27 Level of Abstraction
Although it is commonly agreed that the competence of abstraction and abstract thinking is one of the most important competences in Computer Science, only a few of these sources define this competence and its processes in a precise manner. Furthermore there is a lack of instruments to test the competence of abstract thinking and to integrate it into teaching. This work will start to close the gap concerning the competence of abstract thinking by deriving a theoretical description of the competence construct of abstract thinking, focusing on a Computer Science perspective. Furthermore, we will present a coding manual based on the model, which can be used to evaluate student assignments. This coding manual is applied to examples of our teaching practice in order to demonstrate its validity
Open forest successional stages and landscape heterogeneity promote wild bee diversity in temperate forests
Recent studies have emphasized forests as crucial habitat for wild bees. In
Europe, most forests are managed following the principles of close-to-nature
silviculture, which combine timber production and nature conservation. How-
ever, open late and early successional stages within these forests are largely
missing, which could be important for wild bees. This highlights that close-to-
nature silviculture alone might not be sufficient to conserve bees within tem-
perate forests. Open structures such as canopy gaps and road verges in forests
could improve habitat for bees. To provide management recommendations for
wild bee conservation in temperate forests, we analyzed how components of
bee beta diversity varied between forest management types and tested how
open structures, namely clear-cuts, canopy gaps, and forest road verges influ-
enced bee abundance, richness, and diversity. In addition, we analyzed the
abundance and percent of red-listed bee species at different scales. Bees were
sampled using 90 pan traps on 45 (1 ha) plots in 2019 and 2020 in the Black
Forest, Germany. Plots were selected in 15 triplets each consisting of three
management types related to different successional stages: unmanaged, close-
to-nature, and small clear-cut. Beta diversity was not consistently nested
highlighting the importance of different management and successional stages
within the landscape to support bees in forests. Abundance, species richness,
and Shannon diversity of bees were highest on clear-cuts, compared to
unmanaged- and close-to-nature plots. At landscape scale, wild bee abundance
increased with canopy openness while wild bee diversity increased with land-
scape heterogeneity. Abundance- and percent of red-listed bee species
increased with the length of forest road verges. We advocate creating habitats
at local scales which offer flowering and nesting resources by providing canopy
gaps. At landscape scale, heterogeneity created through different forest succes-
sional stages is needed to conserve the entire community of wild bees
Nestin(+) Tissue-Resident Multipotent Stem Cells Contribute to Tumor Progression by Differentiating into Pericytes and Smooth Muscle Cells Resulting in Blood Vessel Remodeling
Tumor vessels with resistance to anti-angiogenic therapy are characterized by the normalization of the vascular structures through integration of mature pericytes and smooth muscle cells (SMC) into the vessel wall, a process termed vessel stabilization. Unfortunately, stabilization-associated vascular remodeling can result in reduced sensitivity to subsequent anti-angiogenic therapy. We show here that blockade of VEGF by bevacizumab induces stabilization of angiogenic tumor blood vessels in human tumor specimen by recruiting Nestin-positive cells, whereas mature vessels down-regulated Nestin-expression. Using xenograft tumors growing on bone-marrow (BM) chimera of C57Bl/6 wildtype and Nestin-GFP transgenic mice, we show for first time that Nestin(+) cells inducing the maturation of tumor vessels do not originate from the BM but presumably reside within the adventitia of adult blood vessels. Complementary ex vivo experiments using explants of murine aortas revealed that Nestin(+) multipotent stem cells (MPSCs) are mobilized from their niche and differentiated into pericytes and SMC through the influence of tumor-cell-secreted factors. We conclude that tissue-resident Nestin(+) cells are more relevant than BM-derived cells for vessel stabilization and therefore have to be considered in future strategies for anti-angiogenic therapy. The identification of proteins mediating recruitment or differentiation of local Nestin(+) cells with potential stem cell character to angiogenic blood vessels may allow the definition of new therapeutic targets to reduce tumor resistance against anti-angiogenic drugs
Development of a Classification Scheme for Errors Observed in the Process of Computer Programming Education
[EN] Every semester, we observe more or less the same principal difficulties among our students who are striving
to learn the intricacies of software development. Basically, they run into the same kind of errors throughout their learning
process as previous student generations. Based on this fact, we suspect that there is a set of underlying problems which
are causing these errors. Our goal is to identify and tackle these basic problems, in order to deal with errors effectively
in our teaching and coaching activities, rather than merely treating observable symptoms. To achieve this, we develop
a comprehensive and topic-independent error classification scheme and employ this to classify errors found in literature
and in our own courses. This classification scheme is mainly based on the cognitive dimensions of the revised Bloom’s
taxonomy for educational objectives. Each error is based on a deficiency in certain competencies. Therefore, it is
possible to develop a set of interventions for each error class, which focuses on the specific deficits that are the main
cause for all the errors of this class.Zehetmeier, D.; Böttcher, A.; Brüggemann-Klein, A.; Thurner, V. (2015). Development of a Classification Scheme for Errors Observed in the Process of Computer Programming Education. En 1ST INTERNATIONAL CONFERENCE ON HIGHER EDUCATION ADVANCES (HEAD' 15). Editorial Universitat Politècnica de València. 475-484. https://doi.org/10.4995/HEAd15.2015.35647548
Juvenile Idiopathic Arthritis:Roma Children Seem to Run More Risk than Non-Roma
Background: Ethnic information regarding juvenile idiopathic arthritis (JIA) exists for various populations across the world but is fully lacking for Roma. We assessed the occurrence and clinical characteristics of JIA in Roma vs. non-Roma children. Methods: We obtained data on all outpatients (n = 142) from a paediatric rheumatology centre (age 3 to 18 years) in the eastern part of Slovakia (Kosice region). We assessed patients’ age, gender, disease type and related extra-articular conditions by ethnicity. We obtained population data from the 2011 census. Results: The share of Roma children was higher in the clinical JIA sample than in the overall population (24.6%, n = 35, Roma in the sample vs. 10.8%, n = 142, Roma in the population, p < 0.05). Moreover, Roma children had been diagnosed more frequently with extra-articular conditions but did not differ in other symptoms. Treatments also did not differ by ethnicity. Conclusion: Roma children had been diagnosed more with JIA than their non-Roma peers. This calls for further research on the causes of this increased disease burden in Roma children
Gastric lactobezoar - a rare disorder?
Gastric lactobezoar, a pathological conglomeration of milk and mucus in the stomach of milk-fed infants often causing gastric outlet obstruction, is a rarely reported disorder (96 cases since its first description in 1959). While most patients were described 1975-1985 only 26 children have been published since 1986. Clinically, gastric lactobezoars frequently manifest as acute abdomen with abdominal distension (61.0% of 96 patients), vomiting (54.2%), diarrhea (21.9%), and/or a palpable abdominal mass (19.8%). Respiratory (23.0%) and cardiocirculatory (16.7%) symptoms are not uncommon. The pathogenesis of lactobezoar formation is multifactorial: exogenous influences such as high casein content (54.2%), medium chain triglycerides (54.2%) or enhanced caloric density (65.6%) of infant milk as well as endogenous factors including immature gastrointestinal functions (66.0%), dehydration (27.5%) and many other mechanisms have been suggested. Diagnosis is easy if the potential presence of a gastric lactobezoar is thought of, and is based on a history of inappropriate milk feeding, signs of acute abdomen and characteristic features of diagnostic imaging. Previously, plain and/or air-, clear fluid- or opaque contrast medium radiography techniques were used to demonstrate a mass free-floating in the lumen of the stomach. This feature differentiates a gastric lactobezoar from intussusception or an abdominal neoplasm. Currently, abdominal ultrasound, showing highly echogenic intrabezoaric air trapping, is the diagnostic method of choice. However, identifying a gastric lactobezoar requires an investigator experienced in gastrointestinal problems of infancy as can be appreciated from the results of our review which show that in not even a single patient gastric lactobezoar was initially considered as a possible differential diagnosis. Furthermore, in over 30% of plain radiographs reported, diagnosis was initially missed although a lactobezoar was clearly demonstrable on repeat evaluation of the same X-ray films. Enhanced diagnostic sensitivity would be most rewarding since management consisting of cessation of oral feedings combined with administration of intravenous fluids and gastric lavage is easy and resolves over 85% of gastric lactobezoars. In conclusion, gastric lactobezoar is a disorder of unknown prevalence and is nowadays very rarely published, possibly because of inadequate diagnostic sensitivity and/or not yet identified but beneficial modifications of patient management
Neurofibromatosis type 1 (NF1) with an unusually severe phenotype due to digeny for NF1 and ryanodine receptor 1 associated myopathy
We describe a 5-year-old girl with marked hypotonia, poor feeding and reduced facial expression since birth. Congenital myopathy was suspected; muscle biopsy showed unspecific type 1 fibre predominance. The possibility of a ryanodine receptor 1 gene (RYR1)-associated myopathy was considered, but not further investigated. At the age of 2years, she presented with exophthalmos. Brain MRI revealed optic pathway glioma. On clinical examination, she had six café-au-lait spots, thus fulfilling the diagnostic criteria for neurofibromatosis type 1 (NF1). The hypotonia was then attributed to NF1. At the age of 3years, she developed scoliosis and had an unusually severe motor delay for NF1, as she was not able to walk independently. Dual pathology was suspected, and muscle MRI showed the typical pattern for RYR1-related myopathy. This was genetically confirmed with the discovery of two heterozygous mutations. Conclusion: NF1 is one of the most frequent genetic diseases in children. RYR1-related myopathy is one of the most frequent causes of congenital myopathy. The combination of these two pathologies has not yet been described. In cases of unusual presentations or clinical course, the possibility of genetic "double trouble” should be considered
Brown Carbon in Primary and Aged Coal Combustion Emission
Smog chamber experiments were conducted to characterize the light absorption of brown carbon (BrC) from primary and photochemically aged coal combustion emissions. Light absorption was measured by the UV-visible spectrophotometric analysis of water and methanol extracts of filter samples. The single-scattering albedo at 450 nm was 0.73 ± 0.10 for primary emissions and 0.75 ± 0.13 for aged emissions. The light absorption coefficient at 365 nm of methanol extracts was higher than that of water extracts by a factor of 10 for primary emissions and a factor of 7 for aged emissions. This suggests that the majority of BrC is water-insoluble even after aging. The mass absorption efficiency of this BrC (MAE365) for primary OA (POA) was dependent on combustion conditions, with an average of 0.84 ± 0.54 m2 g-1, which was significantly higher than that for aged OA (0.24 ± 0.18 m2 g-1). Secondary OA (SOA) dominated aged OA and the decreased MAE365 after aging indicates that SOA is less light absorbing than POA and/or that BrC is bleached (oxidized) with aging. The estimated MAE365 of SOA (0.14 ± 0.08 m2 g-1) was much lower than that of POA. A comparison of MAE365 of residential coal combustion with other anthropogenic sources suggests that residential coal combustion emissions are among the strongest absorbing BrC organics
Ex vivo validation of magnetically actuated intravascular untethered robots in a clinical setting
Intravascular surgical instruments require precise navigation within narrow vessels, necessitating maximum flexibility, minimal diameter, and high degrees of freedom. Existing tools often lack control during insertion due to undesirable bending, limiting vessel accessibility and risking tissue damage. Next-generation instruments aim to develop hemocompatible untethered devices controlled by external magnetic forces. Achieving this goal remains complex due to testing and implementation challenges in clinical environments. Here we assess the operational effectiveness of hemocompatible untethered magnetic robots using an ex vivo porcine aorta model. The results demonstrate a linear decrease in the swimming speed of untethered magnetic robots as arterial blood flow increases, with the capability to navigate against a maximum arterial flow rate of 67 mL/min. The untethered magnetic robots effectively demonstrate locomotion in a difficult-to-access target site, navigating through the abdominal aorta and reaching the distal end of the renal artery
Increased Seroreactivity to Glioma-Expressed Antigen 2 in Brain Tumor Patients under Radiation
Background: Surgery and radiation are the mainstays of therapy for human gliomas that are the most common primary brain tumors. Most recently, cell culture and animal studies provided the first convincing evidence that radiation not only eliminates tumor cells, but also modulates the immune response and likely improves anti-tumor immunotherapy. Methology/Pricipal Findings: We present an in vivo study that analyzes the effects of radiation on the immune response in tumor patients. As readout system, we utilized the reactivity of glioma patients ’ sera against antigen GLEA2 as the most frequent antigen immunogenic in glioblastoma patients. We established an ELISA assay to analyze reactivity of 24 glioblastoma patients over a period of several months. As control we used 30 sera from healthy donors as well as 30 sera from lung cancer patients. We compared the course of GLEA2 seroreactivity at different times prior, during and after radiation. The GLEA2 seroreactivity was increased by the time of surgery, decreased after surgery, increased again under radiation, and slightly decreased after radiation. Conclusions/Significance: Our results provide in vivo evidence for an increased antibody response against tumor antigens under radiation. Antigens that become immunogenic with an increased antibody response as result of radiation can serv
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