8,655 research outputs found
African origin of the malaria parasite Plasmodium vivax.
No full textPlasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that inhibits the expression of its receptor, the Duffy antigen, on human erythrocytes. The emergence of this protective allele is not understood because P. vivax is believed to have originated in Asia. Here we show, using a non-invasive approach, that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. Sequence analyses reveal that ape parasites lack host specificity and are much more diverse than human parasites, which form a monophyletic lineage within the ape parasite radiation. These findings indicate that human P. vivax is of African origin and likely selected for the Duffy-negative mutation. All extant human P. vivax parasites are derived from a single ancestor that escaped out of Africa
A Study of -dipath Colourings of Oriented Graphs
No full textWe examine -colourings of oriented graphs in which, for a fixed integer , vertices joined by a directed path of length at most must be
assigned different colours. A homomorphism model that extends the ideas of
Sherk for the case is described. Dichotomy theorems for the complexity of
the problem of deciding, for fixed and , whether there exists such a
-colouring are proved
Increasing density enhances pollination and fecundity in the rewarding orchid Gymnadenia conopsea
No full textConspecific density is an important factor in determining the fecundity of pollinator-dependent plants. However, the outcome of increased conspecific density can range from reduced per capita pollination rates and fecundity (competition) to increased per capita pollination rates and fecundity (facilitation). I tested whether local conspecific density influenced pollination and fecundity in the rewarding orchid, Gymnadenia conopsea. I measured the distance to each of the nearest five plants in sixty patches of varying density in a large population in the Italian Apennine mountains. I examined whether pollen removal, pollen deposition, fruit, and seed set varied according to mean distance from conspecifics and plant height. After controlling for plant position in the population, the proportion of pollen removal, pollen deposition, and fruit set decreased with increasing distance from conspecifics, while pollen removal and deposition, but not fruit set, increased with increasing plant height. The proportion of viable seeds per fruit did not vary according to conspecific distance. Decreases in pollen removal, pollen deposition, and fruit set occurred within an average of 1 m distance from conspecific plants, indicating that local aggregation is an important determinant of both pollination success and fecundity. These results suggest that despite being a geographically widespread orchid, G. conopsea may suffer reduced fecundity when it occurs in small, isolated populations. Such field investigations can potentially lead to better predictions for successful re-establishment of populations of orchids under conservation-aided restoration efforts
Influence of distance from conspecific and heterospecific co-flowering plants on pollination and fecundity in the nectarless orchid Dactylorhiza sambucina
No full textBackground
The relative influence of both conspecific and heterospecific plant density on the fecundity of generalist rewardless plants is unclear.
Aims
To test whether distance from both conspecific and heterospecific plants influence pollen removal, deposition, and fruit set in the nectarless orchid, Dactylorhiza sambucina that co-flowers with the rewarding Ranunculus apenninus.
Methods
I experimentally translocated D. sambucina inflorescences and measured pollen removal and deposition rates. I measured plant height and distance to D. sambucina and R. apenninus plants in 30 D. sambucina patches of varying density. I quantified the proportion of pollen removed, pollinia deposited, and fruit set and tested whether these vary according to plant height and distance to both D. sambucina and R. apenninus.
Results
Translocated inflorescences outside the population had a higher proportion of pollen removal than control plants within the population, while pollinia deposition rates did not differ. Increased D. sambucina height increased pollen removal rates, while increasing distance from R. apenninus resulted in both increased pollen deposition and fruit set.
Conclusion
Pollination and fecundity of a nectarless orchid may increase with increasing distance from rewarding heterospecifics. This study improves our understanding of how the fecundity of rewardless plants is influenced by co-flowering plants
B.S. Johnson and Maureen Duffy: Aspiring Writers: A Conversation with Maureen Duffy
No full textMaureen Duffy and B.S. Johnson met at King’s College London in 1956 when they both enrolled to read for a degree in English Literature. They became friends and colleagues through their contributions to Lucifer, the college literary magazine and the wider University of London poetry scene. They later joined forces in the Writer’s Action Group and campaigned for public lending rights for authors. Maureen kindly agreed to be interviewed about her relationship with Johnson, but in addition to this her interview sheds light on the socio-political context of British post-war writing. Maureen was born in 1933 in Worthing, Sussex and came to prominence in 1962 with the autobiographical novel That’s How It Was. Although mainly known for her poetry, her prose work has received critical and popular acclaim. Gor Saga (1981) was dramatised and broadcast by the BBC in 1988 as First Born, a three-part mini-series vehicle for Charles Dance. She is also the author of 16 plays for stage, television and radio. Maureen is well known as a humanist and gay rights activist and for her work championing the financial and legal interests of writers. She is currently the President of the Authors Licensing and Copyright Society, and a Fellow and Vice President of the Royal Society of Literature. This interview took place in London in July 2013 and first appeared in the inaugural edition of B.S.J: The B. S. Johnson Journal
Data protection: the challenges facing social networking
No full textThe popularity of social networking sites has increased dramatically over the past decade. A recent report indicated that thirty-eight percent of online users have a social networking profile. Many of these social networking site users (SNS users) post or provide personal information over the internet every day. According to the latest OfCom study, the average adult SNS user has profiles on 1.6 sites and most check their profiles at least once every other day. However, the recent rise in social networking activity has opened the door to the misuse and abuse of personal information through identity theft, cyber stalking, and undesirable screenings by prospective employers. Behavioral advertising programs have also misused personal information available on social networking sites. Society is now facing an important question: what level of privacy should be expected and required within the social networking environment
Duffy, J S, A11929
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/427965Surname: Duffy. Given Name(s) or Initials: J S. Military Service Number or Last Known Location: A11929. Prisoner of War Enquiry Card Index Number: K.183. Division Enquiry: Qld. Rank: AC1. Unit: 77th Sqn .326722
Item: [2016.0049.60227] "Duffy, J S, A11929
No-Nonsense Branding A Practical Talk about Building Your Author Brand
No full textYou’ve likely been told that as an author, you are a brand. What does that really mean, and how can you develop your brand to maximize your exposure and appeal? In this presentation, Desireé Duffy from Black Château cuts through the fluff and discusses practical ways to build your brand as an author. Topics include why you need a professional-looking head shot, a well-written bio, the right social media presence, and why your personal brand matters when preparing for your pitch for media interviews and articles
Learning for design reuse
No full textOver the past decade 'design assistance', i.e. where the computer is viewed as an Intelligent Design Assistant (IDA) [MacCallum-etal85], has emerged in knowledge based design support and has formed the basic research strategy for the CAD Centre, University of Strathclyde, since the mid-80s. Within this philosophy, an IDA would act as a colleague to a designer, providing guidance, learning from past design experiences, carrying out semi and fully automated tasks, explaining its reasoning and in essence complementing the designer's own natural skills, and thus leaving the ultimate decision making, control and responsibility with the designer
Preface to Special Issue: Advanced doping methods in semiconductor devices and nanostructures
No full textImprovements in semiconductor technology and downscaling have required continuous efforts of the scientific community to solve new challenges in the doping of semiconductor materials. Semiconductor devices, as well as their doping needs, are now undergoing profound change, from the introduction of 3D na- nostructured CMOS architectures to new materials and processes for exciting applications in nanoelectronics, quantum technology, optoelectronics, plasmonics, etc.
This special issue, under the valuable and inspiring guidance of Giuliana Impellizzeri, Editor, focuses on the recent progress in the area of doping methodologies for different advanced applications in semiconductor technology. It is composed of fifteen invited review papers and four regular original papers. The review papers address doping strategies for advanced finFET and nanowire FET devices (A. Veloso), applications of ion implantation in advanced silicon devices (M.I. Current), deterministic doping methods for applications in quantum technology (D.N. Jamieson), doping characterization in 3D structures (W. Vandervorst), modeling of doping processes (in reviews by N. Zographos, L. Pelaz and S.F. Lombardo), doping by pulsed laser melting (in reviews by K. Huet and W. Yang) and flash lamp annealing (S. Prucnal), molecular monolayers for conformal doping (L. Ye), doping of nanostructures (in reviews by S.A. Dayeh and E. Arduca), and doping of III–V semiconductors (in reviews by H. Aldridge and P. Pampili).
We would like to gratefully acknowledge all the contributing authors for sharing their valuable knowledge and expertise, as well as reviewers for their insightful comments and suggestions: all have contributed to the success of this special issue. We hope the papers presented here provide a representative overview of the current progress in semiconductor doping across most classes of semiconductors that are driving advanced applications and will stimulate new exciting research in this field, thus enabling even further progress in semiconductor technolog
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