3,043 research outputs found
Secretion of a Differentiated Cuticle after Apolysis in vitro in Cockroach Leg Integument
Pieces of the integument cut off from the hind tibiae of the freshly moulted adult cockroaches were cultivated in vitro. The epidermis reacted to the application of 2 x 10-5 mol l-1 ecdysterone by an apolysis. If thereafter the hormone concentration stayed above a concentration of 2 x 10-7 mol l-1 only epicuticle and exocuticle were deposited. However, when the hormone concentration was reduced below a critical threshold, that was possibly between 2x10-7 and 2x10-8 mol l-1, a composite procuticle with exocuticle and endocuticle was deposited. Neither application of dibutyryl-cAMP to the culture medium, nor co-cultivation of the ventral nerve cord of a freshly moulted adult had distinct effects. Obviously, bursicon was not necessary for deposition of the endocuticle; instead, Riddiford´s sequential cascade model was fulfilled. The cuticle also developed the typical patterns of sclerotization independently of the application of dibutyryl-cAMP and the co-cultivation of a nerve cord
Neural manifestation of cognitive and precognitive mismatch detection in early infancy
We recorded event-related potentials (ERPs) in 2-month-old infants in two different states of alertness: awake and asleep. Syllables varying in vowel duration (long vs short) were presented in an oddball paradigm, known to elicit a mismatch brain response. ERPs of both groups showed a mismatch response reflected in a positivity followed by a frontal negativity. While the positivity was present as a function of the stimulus type (present for long deviants only), the negativity varied as a function of the state of alertness (present for awake infants only). These data indicate a functional separation between precognitive and cognitive aspects of duration mismatch essential for the distinction between long and short vowels during early infancy
Reinforcement Learning-supported AB Testing of Business Process Improvements: An Industry Perspective
In order to better facilitate the need for continuous business process
improvement, the application of DevOps principles has been proposed. In
particular, the AB-BPM methodology applies AB testing and reinforcement
learning to increase the speed and quality of improvement efforts. In this
paper, we provide an industry perspective on this approach, assessing
requirements, risks, opportunities, and more aspects of the AB-BPM methodology
and supporting tools. Our qualitative analysis combines grounded theory with a
Delphi study, including semi-structured interviews and multiple follow-up
surveys with a panel of ten business process management experts. The main
findings indicate a need for human control during reinforcement learning-driven
experiments, the importance of aligning the methodology culturally and
organizationally with the respective setting, and the necessity of an
integrated process execution platform
State and taxes : analysis of the accountant’s relevance in calculating public revenue
Esse estudo teve por objetivo estabelecer a relevância da atuação do profissional contábil a partir da relação entre as receitas correntes da União que estão sob a sua responsabilidade a partir de pesquisa qualitativa, descritiva e documental. Para tanto, foi contextualizado o surgimento do Estado e a importância dos tributos para financiar e atingir os seus objetivos de estabelecimento do bem comum, além do surgimento da contabilidade pública e do papel do profissional contábil como indispensável para o registro e apuração dos dados que geram a obrigação tributária para contribuintes e receita pública para o ente estatal. Para estabelecer relação das receitas públicas com o exercÃcio do profissional contábil foram efetuadas apurações de dados disponibilizados pelo governo federal, o que resultou na análise da representatividade das Receitas Tributárias e de Contribuições sobre o total de Receitas Correntes da União entre de 2000 e 2019, cujos dados apontaram para percentuais superiores a 80% para todo o perÃodo. Também foi analisada a representatividade das receitas da União de responsabilidade profissional do contador sobre o PIB, no perÃodo entre 2000 e 2019, sendo que as receitas tributárias e de contribuições apresentaram cerca de 20% do PIB, mostrando a menor relação de 18,10% em 2000 e a maior de 21,27% em 2005, evidenciando a importância do profissional contábil sobre a apuração das receitas da União e contribuindo para o fortalecimento da classe contábil. Como esse estudo tratou das receitas tributárias da União, estudos futuros podem ser efetuados sob a ótica dos Estados e/ou MunicÃpios.This study aimed to establish the relevance of the accounting professional's performance based on the relationship between the current revenues of the Union that are under his responsibility through qualitative, descriptive and documentary research. To this end, the emergence of the State and the importance of taxes to finance and achieve its objectives of establishing the common good were contextualized, in addition to the emergence of public accounting and the role of the accounting professional as indispensable for the registration and verification of the data that generate the tax obligation for taxpayers and public revenue for the state entity. In order to establish a relationship between public revenues and the practice of accounting professionals, data were made available by the federal government, which resulted in the analysis of the representativeness of Tax Revenues and Contributions on the total of Current Federal Revenue between 2000 and 2019, whose data pointed to percentages above 80% for the entire period. The representativeness of the Union's revenue from the accountant's professional responsibility over the GDP for the period between 2000 and 2019 was also analyzed, with tax and contribution revenues accounting for around 20% of GDP, with the lowest ratio being 18.10 % in 2000 and the highest of 21.27% in 2005, highlighting the importance of the accounting professional in calculating the Union's revenues, contributing to the strengthening of the accounting class. As this study dealt with the Union's tax revenues, future studies can be carried out from the perspective of the States and/or Municipalities
Die Wirkung von Clopidogrel auf die Expression inflammationsrelevanter Gene im Endotoxin-Modell der Maus
Die Sepsis ist das Ergebnis einer Infektion gepaart mit der komplexen systemischen Entzündungsreaktion des Wirtsorganismus auf dieselbe. Es gibt verschiedene Mechanismen, in deren Folge die systemische Entzündungsreaktion zum Versagen multipler Organsysteme führen kann. Thrombozyten spielen eine entscheidende Rolle für die Pathogenese des SIRS und der Sepsis. In tierexperimentellen und retrospektiven Studien konnte ein Benefit für die Gabe von Thrombozytenaggregationshemmern, wie Clopidogrel, bei systemischer Entzündung gezeigt werden. Ziel der vorliegenden Arbeit ist die Untersuchung eines möglichen Einflusses von Clopidogrel auf die Expression inflammationsrelevanter Gene im Endotoxin-Modell der Maus. Die zu untersuchenden Mäuse wurden randomisiert vier Versuchsgruppen zugeteilt: 1. K-Gruppe: i.p. NaCL 2. S-Gruppe: i.p. LPS 3. CK-Gruppe: Clopidogrel+i.p. NaCl 4. CS-Gruppe: Clopidogrel+i.p. LPS. Analysiert wurden fünf ausgewählte Gene (Il-6, Il-10, Hif1a, Myd88, PAI-1) mittels Real-Time-PCR in Herz, Leber und Gehirn. Versuchstiere mit LPS-Injektion zeigen geringere Thrombozytenzahlen als Tiere ohne LPS-Injektion. Dieser LPS-induzierte Thrombozytenabfall kann durch die Gabe von Clopidogrel verhindert werden. Weiterhin zeigt sich bei fast allen Genen in Herz, Leber und Hirn eine massive Zunahme der Transkriptionsaktivität nach LPS-Injektion. Clopidogrel führt nur bei einzelnen Genen in Herz und Leber zu geringen Veränderungen der Genexpression. Nur bei Hif1a in der Leber führt Clopidogrel zu einer geringen Abschwächung der, durch LPS-Injektion, gesteigerten Transkriptionsaktivität. In der vorliegenden Arbeit hat Clopidogrel fast keine Wirkung auf die organspezifische Genexpression. Somit scheinen Thrombozyten bzw. Thrombozyten-Leukozyten-Interaktionen keine Auswirkung auf die Genexpression in den Organen zu haben. Der Benefit von Clopidogrel bei Sepsis ist demnach möglicherweise vor allem auf die antithrombotische Wirkkomponente der Medikamente zurückzuführen
Complex adaptive systems appraoch to social entrepreneurship business model designs within local government
This research study set out to understand social entrepreneurship business model design
paradigms within the complex environments of local governments in South Africa. Although
the current theory base suggests that social entrepreneurship ventures in local government
also known as public-sector entrepreneurship, is severely limited by regulatory constraints,
social entrepreneurs have a mandate to alleviate the service delivery pressures on local
government by engaging in robust action and creating alternative service delivery models,
especially in the terrain of electricity distribution, water reticulation and waste management
services to communities. The research study has found that social entrepreneurs do indeed
deliver on this mandate and that they actively see the private sector as a pivotal stakeholder
in solving market failures. The empirical research is however very limited and almost absent
as to how business model designs within this context should account for the overwhelming
complexity of local government services as there exists a paradox between the simple and
causal-based business model and the complex nature of the enacted environment.
It can be concluded that the exploratory research has achieved its aim to answer the research
problems, namely: To understand the rules and logic of social entrepreneurship business
models, how this model creates network value, how stakeholders are included in this model,
how it creates social impact, and lastly how the model adapts to complex environments. In
summary, the findings show that especially the individual contexts of the social entrepreneur
and the content and capabilities of the organisation are focal elements of social
entrepreneurship business models. These business models create and capture value by virtue
of its network interface and stakeholder management mechanisms and that private sector
partnerships have a key role in this network. The social enterprise can be construed as a
complex adaptive system that senses and adapts to the contextual environment so that it can
create scalable and sustainable solutions. These findings are therefore significant and will
consequently be summarised in more depth by the following subsections.
Although an explorative approach was conducted, the qualitative interviews with 15
respondents, five from each sector in the sample group, provided rich insights that could be
empirically validated through triangulation. Although it has not been definitively validated by
quantitative methods, this could pose an avenue for further research. The study yielded
exciting findings that emphasised the value of shifting the design paradigm of business models
towards a theoretical frame that aligns praxis with academia. Complex adaptive systems
theory provided an invaluable framework for analysing the research problem and has achieved
the research aims beyond expectations. One of the key findings has shown that the
manifestation of the social business at its heart vests in the rules and logic of the social
entrepreneur. Therefore, if the social entrepreneur can grasp the theoretical context of
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complex adaptive business models, it could potentially provide a new and exciting avenue for
entrepreneurial paradigms.
Finally, the five research questions yielded emerging themes that were aligned with the
conceptual framework that was developed by triangulating three different bases of theory and
consequently not only validated this conceptual framework, but also yielded deep insights that
strengthened and developed the proposed framework into a testable and viable frame of
business model design thinking. This new theoretical framework could provide an ontological
model that may prove to become an invaluable tool for organisational development
practitioners, executive managers and entrepreneurs alike to develop sustainable business
models.Mini Dissertation (MBA)--University of Pretoria, 2019.ms2020Gordon Institute of Business Science (GIBS)MB
The Co-Ni distribution in decagonal Al69.7(4)Co10.0(4)Ni20.3(4)
The Co—Ni distribution in d-Al69.7(4)Co10.0(4)Ni20.3(4) was investigated based on X-ray and neutron diffraction data. The structure was modelled in higher dimensional space using the ‘charge-flipping' and ‘low-density elimination' methods and it was quantitatively refined in three-dimensional space employing a pseudo-approximant approach. In higher-dimensional description, the Co atoms are found at the centre of one of the two symmetry independent occupation domains, enclosed by regions mainly occupied by Ni. The other occupation domain is mostly occupied by Al. In physical space Co atoms are located in the centres of small Al pentagons and form pentagonal units, which are arranged in decagonal rings. On these sites Co is partly substituted by Ni, while all other transition metal sites are occupied by Ni and to a minor degree by Al. The fraction of Co found on transition metal sites decreases with decreasing Co-Co distances, whereby Co is replaced by N
Probing the Drosophila retinal determination gene network in Tribolium (II): The Pax6 genes eyeless and twin of eyeless
AbstractThe Pax6 genes eyeless (ey) and twin of eyeless (toy) are upstream regulators in the retinal determination gene network (RDGN), which instructs the formation of the adult eye primordium in Drosophila. Most animals possess a singleton Pax6 ortholog, but the dependence of eye development on Pax6 is widely conserved. A rare exception is given by the larval eyes of Drosophila, which develop independently of ey and toy. To obtain insight into the origin of differential larval and adult eye regulation, we studied the function of toy and ey in the red flour beetle Tribolium castaneum. We find that single and combinatorial knockdown of toy and ey affect larval eye development strongly but adult eye development only mildly in this primitive hemimetabolous species. Compound eye-loss, however, was provoked when ey and toy were RNAi-silenced in combination with the early retinal gene dachshund (dac). We propose that these data reflect a role of Pax6 during regional specification in the developing head and that the subsequent maintenance and growth of the adult eye primordium is regulated partly by redundant and partly by specific functions of toy, ey and dac in Tribolium. The results from embryonic knockdown and comparative protein sequence analysis lead us further to conclude that Tribolium represents an ancestral state of redundant control by ey and toy
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