624 research outputs found
Predicting the entrepreneurial intentions of university students: applying the theory of planned behaviour in Zambia, Africa
The current paper contributes to the entrepreneurial intention (EI) literature by applying the theory of planned behaviour (TPB) in a developing African country with unique socio-economic and cultural context. Thus it examines the influence of social norms, personal attitudes and perceived behavioural control on business start-up intentions. Based on a quantitative approach, primary survey data were collected from 306 final year undergraduate students at a public university. The data were analyzed using correlation and hierarchical regression techniques. Controlling for age, gender and field of study, the findings indicate that each of the attitudinal antecedents is significantly positively related to EI, with an overall R2 = 0.543. For scholars, enterprise support practitioners and policy makers, the study shows that the TPB can be used to understand how to promote business start-up in developing countries with socio-economic and cultural contexts which are mostly different from developed countries where the subject is heavily researched. Specifically, mechanisms to develop entrepreneurial capabilities among citizens, improve societal norms and individual attitudes toward entrepreneurship would significantly promote entrepreneurship. The study also makes a valuable contribution to the under-researched context of Zambia and African entrepreneurship
Exploring entrepreneurial intention’s mediating role in the relationship between self-efficacy and nascent behaviour: evidence from Zambia, Africa
Purpose –This paper examines the mediating role of entrepreneurial intention (EI) in relation to the influence of the five dimensions of entrepreneurial self-efficacy (ESE) on nascent behaviour. Design/methodology/approach – The study relies on a quantitative approach where primary data were collected from 294 final year undergraduate students at a public university in Zambia. The data were examined by using correlation, logistic regression and mediation analyses. Findings – The findings indicate that each of the five dimensions of ESE is positively and significantly related with EI. Additionally, each of the ESE dimensions, except the financial aspect, is positively correlated with nascent behaviour. Lastly, the results show that the influence of ESE dimensions on nascent behaviour is significantly mediated by intention. Research limitations/implications –The study took place in a public university in Zambia; more universities could be involved to improve the generalisability of the study conclusions. Practical implications –The study shows that the five ESE dimensions positively influence not only business start-up intention but also nascent behaviour. To motivate graduates’ involvement in business start-up, there is a need to tailor training and practical pedagogical approaches on entrepreneurship that are focused on developing the five ESE dimensions. Originality/value – This paper extends an emerging body of knowledge which has not been fully investigated in terms of the mediating role of intention on the relationships between dimensions of ESE and nascent behaviour. The study also makes a valuable contribution to the under-researched context of Zambia and African entrepreneurship
LaZnB5O10, the first lanthanum zinc borate
Lanthanum zinc pentaÂborate, LaZnB5O10, was synthesized by flux-supported solid-state reaction. It is a member of the LnMB5O10 (Ln = rare earth ion and M = divalent metal ion) structure type. The crystal shows a three-dimensional structure constructed from two-dimensional {[B5O10]5−}n layers with the lanthanum (coordination number nine) and zinc (coordination number six) ions filling in the interÂlayers
EVORA: Deep Evidential Traversability Learning for Risk-Aware Off-Road Autonomy
Traversing terrain with good traction is crucial for achieving fast off-road
navigation. Instead of manually designing costs based on terrain features,
existing methods learn terrain properties directly from data via
self-supervision, but challenges remain to properly quantify and mitigate risks
due to uncertainties in learned models. This work efficiently quantifies both
aleatoric and epistemic uncertainties by learning discrete traction
distributions and probability densities of the traction predictor's latent
features. Leveraging evidential deep learning, we parameterize Dirichlet
distributions with the network outputs and propose a novel uncertainty-aware
squared Earth Mover's distance loss with a closed-form expression that improves
learning accuracy and navigation performance. The proposed risk-aware planner
simulates state trajectories with the worst-case expected traction to handle
aleatoric uncertainty, and penalizes trajectories moving through terrain with
high epistemic uncertainty. Our approach is extensively validated in simulation
and on wheeled and quadruped robots, showing improved navigation performance
compared to methods that assume no slip, assume the expected traction, or
optimize for the worst-case expected cost.Comment: Under review. Journal extension for arXiv:2210.00153. Project
website: https://xiaoyi-cai.github.io/evora
Neuropilin 1 expression correlates with differentiation status of epidermal cells and cutaneous squamous cell carcinomas
Neuropilins (NRP) are cell surface receptors for VEGF and SEMA3 family members. The role of NRP in neurons and endothelial cells has been investigated, but the expression and role of NRP in epithelial cells is much less clear. Herein, the expression and localization of neuropilin 1 (NRP1) was investigated in human and mouse skin and squamous cell carcinomas (SCC). Results indicated that NRP1 mRNA and protein was expressed in the suprabasal epithelial layers of skin sections. NRP1 staining did not overlap with that of keratin 14 (K14) or proliferating cell nuclear antigen, but did colocalize with staining for keratin 1, indicating that differentiated keratinocytes express NRP1. Similar to the expression of NRP1, VEGF-A was expressed in suprabasal epithelial cells, whereas Nrp2 and VEGFR2 were not detectable in the epidermis. The expression of NRP1 correlated with a high degree of differentiation in human SCC specimens, human SCC xenografts, and mouse K14-HPV16 transgenic SCC. UVB irradiation of mouse skin induced Nrp1 upregulation. In vitro, Nrp1 was upregulated in primary keratinocytes in response to differentiating media or EGF-family growth factors. In conclusion, the expression of NRP1 is regulated in the skin and is selectively produced in differentiated epithelial cells. NRP1 may function as a reservoir to sequester VEGF ligand within the epithelial compartment, thereby modulating its bioactivity
Higher whole-blood selenium is associated with improved immune responses in footrot-affected sheep
We reported previously that sheep affected with footrot (FR) have lower whole-blood selenium (WB-Se) concentrations and that parenteral Se-supplementation in conjunction with routine control practices accelerates recovery from FR. The purpose of this follow-up study was to investigate the mechanisms by which Se facilitates recovery from FR. Sheep affected with FR (n = 38) were injected monthly for 15 months with either 5 mg Se (FR-Se) or saline (FR-Sal), whereas 19 healthy sheep received no treatment. Adaptive immune function was evaluated after 3 months of Se supplementation by immunizing all sheep with a novel protein, keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity (DTH) skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. Innate immunity was evaluated after 3 months of Se supplementation by measuring intradermal responses to histamine 30 min after injection compared to KLH and saline, and after 15 months of Se supplementation by isolating neutrophils and measuring their bacterial killing ability and relative abundance of mRNA for genes associated with neutrophil migration. Compared to healthy sheep, immune responses to a novel protein were suppressed in FR-affected sheep with smaller decreases in FR-affected sheep that received Se or had WB-Se concentrations above 250 ng/mL at the time of the immune assays. Neutrophil function was suppressed in FR-affected sheep, but was not changed by Se supplementation or WB-Se status. Sheep FR is associated with depressed immune responses to a novel protein, which may be partly restored by improving WB-Se status (> 250 ng/mL)
Real-time reverse transcriptase PCR assay for detection of human metapneumoviruses from all known genetic lineages
The discovery of human metapneumovirus and its implications for respiratory tract disease have emphasized the need for a sensitive, specific, and rapid assay to detect this virus in a clinical setting. It recently became clear that human metapneumovirus can be grouped into at least four genetic lineages. Previously described assays for the detection of human metapneumovirus were developed by using limited sequence information and failed to detect viruses from all four genetic lineages with comparable sensitivities. Here we describe the development and evaluation of a real-time reverse transcriptase PCR assay that detects human metapneumovirus from the four known genetic lineages with equal specificities and sensitivities
Enhanced Spike-specific, but attenuated Nucleocapsid-specific T cell responses upon SARS-CoV-2 breakthrough versus non-breakthrough infections
SARS-CoV-2 vaccine breakthrough infections frequently occurred even before the emergence of Omicron variants. Yet, relatively little is known about the impact of vaccination on SARS-CoV-2-specific T cell and antibody response dynamics upon breakthrough infection. We have therefore studied the dynamics of CD4 and CD8 T cells targeting the vaccine-encoded Spike and the non-encoded Nucleocapsid antigens during breakthrough infections (BTI, n=24) and in unvaccinated control infections (non-BTI, n=30). Subjects with vaccine breakthrough infection had significantly higher CD4 and CD8 T cell responses targeting the vaccine-encoded Spike during the first and third/fourth week after PCR diagnosis compared to non-vaccinated controls, respectively. In contrast, CD4 T cells targeting the non-vaccine encoded Nucleocapsid antigen were of significantly lower magnitude in BTI as compared to non-BTI. Hence, previous vaccination was linked to enhanced T cell responses targeting the vaccine-encoded Spike antigen, while responses against the non-vaccine encoded Nucleocapsid antigen were significantly attenuated
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