Darwin College Students' Association

Research Talks

All members of Darwin are encouraged to present their research at informal seminars held on Tuesdays and Thursdays during term. Everyone is welcome, whatever your degree or discipline.

Darwin members pick up lunch from 12:00, taking it into the Richard King Room (on the left at the top of the stairs leading to the dining hall) or 1 Newnham Terrace (straight through at the far end of the dining hall). Wine is served. Non-Darwin members are welcome to attend, although lunch is only available to guests of members. The talk begins at about 1:15 and lasts for about 20 minutes and is followed by questions over coffee. We adjourn at 2:00pm at the latest.

Upcoming Talks

Thursday 10 May 2018
The Richard King Room, Darwin College
Dr William Alston, Institute of Astronomy, University of Cambridge

Black holes are the most extreme objects found in the universe. They provide a one-way passage to the unknown, places where our understanding of physics breaks down. Pioneering work over the last century has transformed black holes from theoretical curiosities, into the domain of the observational astronomer. These gravitational monsters reside in the centre of all galaxies in the universe, and are intimately linked to the formation and evolution of stars and galaxies we observe today. Despite their enormous size, our current telescopes are unable to spatially resolve them on the sky. We therefore resort to indirect methods to zoom in on the region directly around the black hole. In this talk, I will describe current efforts to spatially map the gas in the immediate vicinity of a black hole as it spirals down the deep gravitational potential well. These observations provide us with information about the two fundamental properties of black holes: their mass and spin.

Past Research Talks

Thursday 12 October 2017
Giancarlo Soavi (Cambridge Graphene Centre)

Laser sources producing nanosecond (10-9 s) to sub-picosecond (10-12 s) pulses (i.e. ultrafast lasers) are deployed in a variety of applications ranging from scientific research, laser surgery, material processing and telecommunications. Regardless of the output wavelength, the majority of ultrafast laser systems employ a mode-locking technique, whereby a nonlinear optical element - called Saturable Absorber (SA) - turns the laser continuous wave output into a train of ultrashort optical pulses. The SA absorption (or optical loss) decreases as the incident light intensity increases. Thus, the SA works as an intensity-dependent optical switch. The key requirements for SAs are fast response time, high modulation depth, broad wavelength range, low optical loss, low-cost and ease of integration into an optical system. Graphene, a one atom thick layer of carbon atoms arranged in a honeycomb lattice, can simultaneously meet all these needs with better performances and lower cost compared to current technologies. In this seminar I will introduce the basic concepts of ultrafast lasers and mode-locking and their importance for technological applications. I will then review the fundamental physical properties that make graphene the ideal candidate as saturable absorber for ultrafast lasers on an extremely broad energy range from visible to THz.

Tuesday 10 October 2017
Daniel H. Weiss, Polonsky-Coexist Senior Lecturer in Jewish Studies in the Faculty of Divinity

Many scholars today view the causing the death of innocent civilians in warfare as an established part of historical Western tradition of just war, so long as those deaths are 'merely foreseen, but not directly intended'. This attitude towards 'collateral damage' or 'double effect' is often traced back to Thomas Aquinas. However, I argue that, contrary to received scholarly assumptions, Aquinas in fact sharply rejects the legitimacy of such forms of killing. Accordingly, premodern Western thought regarding just war may stand in a much sharper discontinuity with modern just war ethics than has previously been recognized, with significant potential implications for contemporary public debates and ethical dilemmas.

Thursday 5 October 2017
Dr. Peter Murray-Rust (Unilever Centre, Dept. Of Chemistry, University of Cambridge)

Peter Murray-Rust, ContentMine [1] and University of Cambridge

Public funding of science and medicine generates 1 trillion dollars of public knowledge per year but most of this is inaccessible to most people. Working with the Wikimedia Foundation we have developed tools for collecting over 6 million of the world's open scientific articles and extracting the facts from them into WikiFactMine (WFM) [2] . We use Wikidata [3] which, with over 40 million "items" from Wikipedia or world authorities, is based on modern Open Web technology. WFM reads every new Open scientific article (starting with biomedicine) and indexes the terms against WikiFactMine. It thus becomes a "knowledge prosthetic" or "amanuensis" so that everyone can immediately find the accumulated knowledge in Wikimedia resources.

We believe that with WikiFactMine the scientific literature becomes accessible to a wide range of people and machines. Data in articles can be automatically indexed on fulltext and diagrammatic content creating the base for a new generation of scientific search engines. We have created a wide range of "dictionaries" from Wikidata, allowing multidisciplinary search of articles (e.g. chemistry, diseases, drugs...) . WikiFactMine can expand "find all chemicals produced by conifers" to 500 phytochemicals and 2000 conifers and search for all of them. "What viral diseases have been reported in West Africa" might inform public health policies in a new manner.

The talk will cover the technology (which anyone can use; ContentMine already has a 15-year old contributing) and the politics of academic publication where revenue is often generated by artificial scarcity. Can we find a better way? Everyone can participate in WikiFactMine.

I thank Charles Matthews and Tom Arrow who created WikiFactMine.

[1] http://contentmine.org [2] https://www.wikidata.org/wiki/Wikidata:WikiFactMine [3] https://www.wikidata.org

Thursday 25 May 2017
Shehar Bano, University College London

Censorship of online communications threatens principles of openness and freedom of information on which the Internet was founded. In the interest of transparency and accountability, and more broadly to develop scientific rigour in the field, we need methodologies to measure and characterize Internet censorship. Such studies will not only help users make informed choices about information access, but also illuminate entities involved in or affected by censorship; informing the development of policy and enquiries into the ethics and legality of such practices. However, many issues around Internet censorship remain poorly understood because of the inherently adversarial and opaque landscape in which it operates. As details about mechanisms and targets of censorship are usually undisclosed, it is hard to define exactly what comprises censorship, and how it operates in different contexts.

My research aims to help fill this gap by developing methodologies to derive censorship ground truth using active and passive data analysis techniques, which I apply to real-world datasets to uncover entities involved in censorship, the targets of censorship, and the effects of such practices on different stakeholders. In this talk, I will provide an overview of my work on Internet censorship from multiple perspectives: (i) measurement of the Great Firewall of China that shows that inference of the censor’s traffic analysis model can enable systematic identification of evasion opportunities that users can exploit to access restricted content, (ii) analysis of network logs collected at an Internet Service Provider (ISP) in Pakistan over a period of escalating censorship to study how censorship affects users’ browsing habits with respect to circumvention, and its economic effects on content providers and ISPs, and (iii) investigation of differential treatment -- an emerging class of censorship where websites (rather than the government) block requests of users they don’t like -- in the context of Tor anonymity network and users of adblocking software.

Tuesday 23 May 2017
Pablo Salas (University of Cambridge)

Collaboration between researchers and policy-makers has perhaps never been as crucial as it is today, in view of the many critical issues that countries, particularly Brazil, face in the context of the Water-Energy-Food (FEW) nexus. A perfect storm of complex interactions, dependencies and vulnerabilities is most likely to be expected in Brazil, given its current environmental and economic situation. On the one hand, climate change is highly likely to change weather patterns, which will detrimentally affect agriculture and biodiversity in Brazil. On the other hand, Brazilian economy relies heavily on exports of natural resources for prosperity, and global changes in demand for commodities will put pressure on the Brazilian economy. In this talk, I will present the main aspects of the complex nexus system, with special focus on the challenges associated to create policy to improve the resilience of the Brazilian FEW Nexus.

Dr Pablo Salas is an Economist and Electrical Engineer by training, with a PhD in Land Economy from the University of Cambridge. He is currently a Research Fellow at the Cambridge Centre for Environment, Energy and Natural Resource Governance (C-EENRG), Department of Land Economy. Dr Salas' wider research examines how interactions among energy, environmental and economic systems can be used to improve global strategies for climate change risk reduction and sustainable economic development. As part of his fellowship, he is also leading the development of various outreach activities at C-EENRG, actively connecting academics with policy makers and innovators.

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