A Revisit of the Two-Pole Caustic Model for GeV Light Curves of Gamma-Ray Pulsars

The GeV light curve of a pulsar is an important probe to detect acceleration regions in its magnetosphere. Motivated by the recent reports on the observations of pulsars by {\it Fermi} Large Area Telescope (LAT), we restudy the two-pole caustic model and revise it to investigate the properties of the light curves in the GeV band. In the revised model, although acceleration gaps can extend from the star surface to the light cylinder along near the last open field lines, the extension of the gaps along the azimuthal direction is limited because of photon-photon pair production process. In such gaps, high-energy photons are emitted uniformly and tangentially to the field lines but cannot be efficiently produced along these field lines where the distances to the null charge surface are larger than $\sim0.9$ times of the distance of the light cylinder, and the effective azimuth extension of the gaps is about $230^\circ$. The model is applied to the four pulsars Vela, PSR J1028-5819, PSR J0205+6449, and PSR J2021+3651 whose light curves obtained with {\it Fermi} have been recently released. The model is successful in reproducing the general feature of the light curves for the four pulsars, and the radial distances of the radio pulse for the four pulsars are estimated.Comment: A reference is correcte

Ecosystem services: An ecophysiological examination

This review aims to discuss ecosystem services, provide illustrative case studies at catchment and local scales and present future research needs. This review discusses the following: (1) Ecosystem services (ES) are those goods and services that are provided by or are attributes of ecosystems that benefit humans. Examples of ES include the timber derived from a forest, the prevention of soil and coastal erosion by vegetation and the amelioration of dryland salinity through prevention of rises in the water table by trees. The provision of ES globally is in decline because of a lack of awareness of the total economic value of ES in the public, policy and political fora. (2) Providing a scientific understanding of the relationships among ecosystem structure, function and provision of ES, plus determining actual economic value of ES, are the central challenges to environmental scientists (including triple-bottom-line economists). (3) Some ES are widely dispersed throughout many different ecosystems. Carbon accumulation in trees and the contribution of biodiversity to ES provision are two examples of highly dispersed attributes common to many ecosystems. In contrast, other ES are best considered within the context of a single defined ecosystem (although they may occur in other ecosystems too). Mangroves as 'nursery' sites for juvenile fish is one example. (4) Examples of catchment-scale and local-scale provision of ES are discussed, along with future research issues for the nexus between ES and environmental sciences. © CSIRO 2005

Standard Cosmology Delayed

The introduction of a delay in the Friedmann equation of cosmological evolution is shown to result in the very early universe undergoing the necessary accelerated expansion in the usual radiation (or matter) dominated phase. Occurring even without a violation of the strong energy condition, this expansion slows down naturally to go over to the decelerated phase, namely the standard Hubble expansion. This may obviate the need for a scalar field driven inflationary epoch.Comment: 12 pages, 3 figures, Revised with more elaborate discussions. Accepted for publication in JCA

International human rights law as a framework for algorithmic accountability

Existing approaches to ‘algorithmic accountability’, such as transparency, provide an important baseline, but are insufficient to address the (potential) harm to human rights caused by the use of algorithms in decision-making. In order to effectively address the impact on human rights, we argue that a framework that sets out a shared understanding and means of assessing harm; is capable of dealing with multiple actors and different forms of responsibility; and applies across the full algorithmic lifecycle, from conception to deployment, is needed. While generally overlooked in debates on algorithmic accountability, in this article, we suggest that international human rights law already provides this framework. We apply this framework to illustrate the effect it has on the choices to employ algorithms in decision-making in the first place and the safeguards required. While our analysis indicates that in some circumstances, the use of algorithms may be restricted, we argue that these findings are not ‘anti-innovation’ but rather appropriate checks and balances to ensure that algorithms contribute to society, while safeguarding against risks

In silico interrogation of the miRNAome of infected haematopoietic cells to predict processes important for human cytomegalovirus latent infection

Abstract Human cytomegalovirus (HCMV) latency in CD34+ progenitor cells is the outcome of a complex and continued interaction of virus and host that is initiated during very early stages of infection and reflects pro and anti-viral activity. We hypothesized that a key event during early infection could involve changes to host miRNAs, allowing for rapid modulation of the host proteome. Here, we identify 72 significantly upregulated miRNAs, and 3 that were downregulated by 6hpi of infection of CD34+ cells which were then subject to multiple in silico analyses to identify potential genes and pathways important for viral infection. The analyses focused on the upregulated miRNAs and were used to predict potential gene hubs or common mRNA targets of multiple miRNAs. Constitutive deletion of one target, the transcriptional regulator JDP2, resulted in a defect in latent infection of myeloid cells; interestingly, transient knockdown in differentiated dendritic cells resulted in increased viral lytic IE gene expression, arguing for subtle differences in the role of JDP2 during latency establishment and reactivation of HCMV. Finally, in silico predictions identified clusters of genes with related functions (such as calcium signaling, ubiquitination and chromatin modification), suggesting potential importance in latency and reactivation. Consistent with this hypothesis, we demonstrate that viral IE gene expression is sensitive to calcium channel inhibition in reactivating dendritic cells. In conclusion, we demonstrate HCMV alters the miRNAome rapidly upon infection and that in silico interrogation of these changes reveals new insight into mechanisms controlling viral gene expression during HCMV latency and, intriguingly, reactivation

Employability initiatives in undergraduate education and application to human nutrition: A scoping review

Human nutrition is a growing field with an increasing job market and high demand for university study, yet graduates report feeling underprepared for and unaware of potential job opportunities. This scoping review aimed to identify employment initiatives used in undergraduate programs to support an evidence-based approach to the development of future initiatives for human nutrition courses. The scoping review following PRISMA-ScR criteria was initially conducted in October 2018 and updated in April 2020. Search terms were selected to identify studies that reported on employability or work-readiness embedded within the course curriculum for undergraduate students. Fourteen papers met the eligibility criteria. Papers included were from Australia (9), United Kingdom (2), United States (1), New Zealand (1) and Germany (1). Papers described initiatives fitting broad categories of placements, project-based industry collaboration, practice-based eLearning, mentoring and building graduate attributes. Placements were the most common type of initiative and project-based industry collaboration demonstrated the highest levels of student and employer satisfaction. The success of initiatives was often attributed to incorporating diverse approaches to real-world, problem-solving skills. Mentoring and eLearning were used to promote employability soft skills, while industry-based placements provided students with practical experience. Placement in specific workplace settings should be representative of the diverse job options for nutrition graduates. Human nutrition degrees should consider incorporating strategies that develop soft skills and project-based skills while exposing students to diverse workplace settings within industry