113 research outputs found
Schulbuchanalyse zum Umgang mit Variablen bei der Einführung von Termen und Gleichungen in der 7. Klasse
In diesem Beitrag wird eine Schulbuchanalyse, als Teil meines Promotionsprojektes,
zum Thema Umgang mit Variablen bei der Einführung von
Termen und Gleichungen vorgestellt. Die Grundlage der Analyse bildet das
Schulbuch Schnittpunkt 7 für Realschulen von 2006 in der Auflage für
Nordrhein-Westfalen. Dabei wird auch der begleitende Serviceband, welcher
über die Schwerpunkte und Intentionen der Schulbuchautoren Auskunft
gibt, in die Analyse mit einbezogen. Die zugrundeliegenden Fragestellungen
lauten: Wie wird der Begriffe Variable eingeführt und wofür
stehen die verwendeten Buchstaben auf den Schulbuchseiten? Was sind die
zugrundeliegenden Objekte für die Lernenden? Und welche impliziten oder
expliziten Begründungen gibt es auf den Seiten? Die Antworten auf diese
Fragen lassen Rückschlüsse auf die Auffassung von Algebra zu, welcher
die Lernenden auf Grundlage dieses Schulbuches erwerben. Um die Einführung
und die Behandlung von Variablen richtig deuten zu können, ist es
wesentlich den Stand der Lernenden zu berücksichtigen, welchen sie auf
Grundlage der Schulbücher der Klassen fünf und sechs erworben haben
Animal Welfare and Food Safety When Slaughtering Cattle Using the Gunshot Method
Simple Summary Transporting cattle from the farm to the slaughterhouse is often stressful for the animal. With the gunshot method, it is stunned using a rifle while together with familiar herd members in an enclosure on the farm. The shot makes the animal unconscious. Then, as in normal slaughter, the animal is bled to death. Finally, it is transported to a nearby slaughterhouse. We aimed to assess the consequences for animal welfare and food safety of using the gunshot method. Twenty Hereford steers were shot with a hunting rifle using small-calibre ammunition from an elevated position and distance of 6-12 m. Each time, only one out of four to seven animals in a 16 x 10 m corral was shot. Based on the animals' behaviour and physiological blood values, stress levels before shooting were low. Eleven animals were considered completely unconscious, while seven showed some signs of consciousness and two were poorly stunned. Two animals were reshot with heavier ammunition. Bleeding was satisfactory and little or no contamination was found on the carcasses. We conclude that the gunshot method is applicable to large beef steers while maintaining a satisfactory level of animal welfare and food safety, provided that the necessary conditions can be achieved. Transporting cattle from farm to slaughterhouse is often stressful for the animal, which can impair the meat quality. With the gunshot method, the animal is stunned with a rifle shot while together with familiar herd members in their home environment, exsanguinated and transported to a nearby slaughterhouse. Aiming to assess the consequences for animal welfare and food safety, 20 Hereford steers aged 18-54 months were shot with .22 Magnum ammunition from an elevated position and distance of 6-12 m. Each time, only one out of four to seven animals in a 16 x 10 m corral was shot. Dressing was done on farm. Based on the animals' behaviour and blood concentrations of cortisol, glucose and lactate, stress levels before shooting were low. Eleven animals were deeply stunned, the consciousness of seven others was ambiguous, and two were poorly stunned. Two animals were reshot. The bleed-out was satisfactory for all animals, and little or no faecal contamination was found on the carcasses. We conclude that the gunshot method is applicable to large beef steers while maintaining a satisfactory level of animal welfare and food safety, provided that the necessary conditions can be attained
Contrastive Representation Learning for Whole Brain Cytoarchitectonic Mapping in Histological Human Brain Sections
Cytoarchitectonic maps provide microstructural reference parcellations of the
brain, describing its organization in terms of the spatial arrangement of
neuronal cell bodies as measured from histological tissue sections. Recent work
provided the first automatic segmentations of cytoarchitectonic areas in the
visual system using Convolutional Neural Networks. We aim to extend this
approach to become applicable to a wider range of brain areas, envisioning a
solution for mapping the complete human brain. Inspired by recent success in
image classification, we propose a contrastive learning objective for encoding
microscopic image patches into robust microstructural features, which are
efficient for cytoarchitectonic area classification. We show that a model
pre-trained using this learning task outperforms a model trained from scratch,
as well as a model pre-trained on a recently proposed auxiliary task. We
perform cluster analysis in the feature space to show that the learned
representations form anatomically meaningful groups.Comment: Accepted to ISBI 202
Denoising Diffusion Probabilistic Models for Image Inpainting of Cell Distributions in the Human Brain
Recent advances in imaging and high-performance computing have made it
possible to image the entire human brain at the cellular level. This is the
basis to study the multi-scale architecture of the brain regarding its
subdivision into brain areas and nuclei, cortical layers, columns, and cell
clusters down to single cell morphology Methods for brain mapping and cell
segmentation exploit such images to enable rapid and automated analysis of
cytoarchitecture and cell distribution in complete series of histological
sections. However, the presence of inevitable processing artifacts in the image
data caused by missing sections, tears in the tissue, or staining variations
remains the primary reason for gaps in the resulting image data. To this end we
aim to provide a model that can fill in missing information in a reliable way,
following the true cell distribution at different scales. Inspired by the
recent success in image generation, we propose a denoising diffusion
probabilistic model (DDPM), trained on light-microscopic scans of cell-body
stained sections. We extend this model with the RePaint method to impute
missing or replace corrupted image data. We show that our trained DDPM is able
to generate highly realistic image information for this purpose, generating
plausible cell statistics and cytoarchitectonic patterns. We validate its
outputs using two established downstream task models trained on the same data.Comment: Submitted to ISBI-202
The Berlin Hepatitis C Manifesto: access to prevention, testing, treatment and care for people who use drugs.
The treatment of hepatitis C has entered a new era since the advent of curative pharmaceuticals. As policy, government and civil society assemble in response, there are still gaps to be addressed. The Manifesto on Hepatitis C and Drug Use, launched in Berlin during the Correlation Hepatitis C Initiative conference in October 2014, was formulated and endorsed by many key organizations in the hepatitis field. The Manifesto takes strides to pinpoint shortcomings in hepatitis action oriented towards the population most affected by the hepatitis C virus (HCV): active drug users. Despite a considerable amount of evidence that active drug users are disproportionately affected by HCV, barriers to care remain. Engagement with representatives of communities of people who inject drugs (PWID) is imperative in order to effectively create guidelines which reflect reality. Unfortunately, widespread systemic stigmatization and lack of trust between affected communities, decision-makers and healthcare professionals have reproduced this divide. The Berlin Manifesto has identified a disconnect between evidence and action which must be answered. In this roundtable discussion, experts from diverse parts of the hepatitis community have contributed their perspectives and experience on access to prevention, testing, and treatment for HCV in PWID. The authors discuss relevant topics such as realities of access to HCV treatment in the United Kingdom, interventions of a regional network of active drug users in Europe and lack of PWID involvement in government policy in Catalonia. Collectively they challenge the neglect of HCV in PWID by many decision-makers and health care professionals and promote a scale-up of integrated prevention and treatment strategies focusing on this population. The authors' conclusions aim to clarify the discourse on hepatitis in order to prevent disease, save lives and work towards eventual hepatitis elimination
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
In vitro effects of imatinib mesylate on radiosensitivity and chemosensitivity of breast cancer cells
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