IPA Recipients for October 2017

Ralph John de la Cruz and Agnes Paras
Institute of Mathematics
College of Science
UP Diliman

Skew ϕ Polar Decompositions. Linear Algebra and its Applications, 531: 129-140, 15 October 2017.

We determine when can we factor out a matrix A as a product of an orthogonal and a skew symmetric matrix, or as a product of a symplectic and a Hamiltonian matrix.

Link to the article: http://www.sciencedirect.com/science/article/pii/S0024379517303294
Impact Factor: (2016/2017) 0.973

________________________________________

Christian Joseph R. Cumagun
Institute of Weed Science, Entomology and Plant Pathology
College of Agriculture and Food Science
UP Los Baños

Evolution of the Wheat Blast Fungus through Functional Losses in a Host Specificity Determinant. Science, 357 (6346): 80-83, 7 July 2017.

Figure 1. Gene-for-gene interactions between Pyricularia oryzae isolates and gramineous plants. Avirulence gene – resistance gene pairs are indicated by bidirectional black arrows. Green arrows indicate compatible interactions. Hyphens indicate non-functional alleles.

Fig. 2. PWT3 and PWT4 serve as the host species specificity barrier for wheat. Spikes of wheat cultivars Norin 4 (N4), Chinese Spring (CS), Transfed (Tfed), and Hope were inoculated with wild types (WT) of Triticum (A), Lolium (B), and Avena (C) isolates; their transformants carrying introduced PWT3 (+3) or PWT4 (+4); and disruptants of PWT3 (D3), PWT4 (D4), or double disruptant (D3D4). Inoculated spikes were incubated for 8 days.

It is seldom in nature that pathogens, normally infecting a limited number of host species, can become pathogenic to new host. In this paper, we have uncovered an important link to a disease which left unchecked could prove devastating to wheat by identifying the genetic mechanism by which the blast fungus Pyricularia oryzae jumped host to wheat. The recurrent loss of function of the avirulence gene PWT3 of the P. oryzae was likely triggered by the widespread use of wheat cultivars lacking the cognate resistance gene Rwt3. As a result, host jump of the fungus from weeds to common wheat occurred. We conclude that the loss of an avirulence gene/resistance gene interaction results in host jump of the blast fungus to common wheat. Therefore, we recommend farmers to cultivate common wheat cultivars that carry both the resistance Rwt3 and Rwt4 to avoid reoccurrence of host jumps and prevent wheat blast disease caused by infection with weed pathogens.

Link to the article: http://science.sciencemag.org/content/357/6346/80
Impact Factor: (2016/2017) 37.205

________________________________________

Kristian Karlo C. Saguin
Department of Geography
College of Social Sciences and Philosophy
UP Diliman

Producing an Urban Hazardscape Beyond the City. Environment and Planning A, 49 (9): 1968-1985, September 2017.

The 2009 Ondoy and 2012/2013 Habagat floods in Metro Manila reveal the historical-geographical roots and the discursive imaginaries about cities, spaces and environments that are often obscured in reports about these disasters. This paper uses the case of stormwater flows and their infrastructural control in Metro Manila and Laguna Lake to trace how flood risk is produced, displaced and managed in cities. Keeping Metro Manila a flood-free city requires modern visions of control of nature and the production of non-city spaces such as Laguna Lake, where a significant volume of urban stormwater flows are displaced, magnifying risk for lake dwellers. The urban production of Laguna Lake as a flood hazardscape or landscape of risk also intersects with a long history of state efforts to develop the lake as an urban ecological frontier to supply the city with its various resource needs. Flood control in Metro Manila and Laguna Lake and the material-discursive production of risk therefore show how urbanization entails the transformation of landscapes and livelihoods in non-city spaces to enable the continued functioning of cities.

Link to the article: http://journals.sagepub.com/doi/abs/10.1177/0308518X17718373
Impact Factor: (2016/2017) 1.389

________________________________________