Publishing’s G20: the digital debate over the future of the book industry (guest-blog)

Polis Intern Lauren Sozio reports on a New York conference on the digital future of book publishing In the past few months, New York’s publishing industry has been hit by its own version of the Wall Street crash. But problems run deeper than the recession’s domino effect and puncture an age-old business model ruled by barons chasing the bestseller, tossing out advances, and collecting royalties. Then along came Google Book Search–certainly not the only harbinger of the industry’s (as we know it today) demise–but the company that altruists love to defend and anti-trusters love to blame. In the advent of the Internet, writers don’t have to play by the rules as PC’s have eroded the formal barriers to publishing and replaced them with a deceptive free-for-all where confusion over copyright, representation, and of course, revenue loom overhead like the Google’s grey computing cloud

Mechanisms of species persistence in fragmented landscapes: A demographic field study on four rodent species

Habitat loss and fragmentation are key drivers of global species loss. In fragmented landscapes species must persist in small, isolated and often degraded habitat patches where they can be subject to high risk of extinction due to deterministic and stochastic forces. Species respond to habitat fragmentation according to species-specific life-history traits, with habitat generalist, edge or mobile species being less impacted compared to specialists and less mobile species. The impact of habitat fragmentation on species and their consequent probability of persistence depends on a series of key, concatenated events occurring at different biological and spatial scales. The response of single individuals to landscape change can translate into effects at the level of populations; coexisting species can reciprocally influence their responses through the alteration of interspecific relationships; inter-population dynamics can also occur, involving the movement of individuals between populations in different habitat fragments and affecting the persistence of entire systems of populations. Given the complexity of factors involved, including direct and interacting responses, it is extremely difficult to understand the actual effects triggered by habitat fragmentation without a thorough knowledge of the underlying ecological mechanisms. The aim of this PhD project was to contribute to understanding the mechanisms underlying the response of species to habitat fragmentation. By following a holistic approach, I used a set of mechanistic field studies on four rodent species specifically designed to investigate the series of key events involved in the persistence of species in fragmented landscapes: 1) Population and individual scale responses of small mammals to patch size, isolation and quality. The aim of this section was to determine the relative effects of landscape structure (habitat amount and configuration) and patch quality (here measured as abundance of shrub resources) on individuals (survival and litter size) and populations (density and colonization/extinction dynamics). A large-scale demographic field study was conducted, encompassing 30 woodland sites nested within three landscapes and surveyed monthly for three years by means of a capture-mark-recapture protocol. Model species was an arboreal rodent, the hazel dormouse (Muscardinus avellanarius), known to be sensitive to habitat loss and fragmentation. Habitat quality influenced populations at different biological scales by concatenated effects: it enhanced individual survival, increased the chances of colonizing vacant patches and sustained higher population densities. It was therefore related to the performance of single populations and systems of populations through re-colonization dynamics. Habitat quality, however, did not influence local extinction probability, which was ultimately related to the extent of available habitat, likely due to the absolute size of populations: a high absolute number of individuals reduces the chances of population extinction. 2) The role of interspecific interactions in shaping small mammal communities in fragmented landscapes. The aim of this section was to evaluate the strength of interspecific interactions as a shaping force of animal communities in fragmented landscapes. A large-scale demographic field study was conducted to measure the degree of competitive interference between species. Model system was constituted by the community of forest-dwelling ground rodents of central Italy, including the species Apodemus sylvaticus, Apodemus flavicollis and Myodes glareolus. Populations, inhabiting 29 wood patches in a fragmented landscape, were surveyed for two years by means of a capture-mark-recapture protocol. I modeled species' distribution as a function of landscape (habitat cover and connectivity provided by hedgerows) and habitat variables (vegetation structure and food resources) to look for evidences of competitive spatial segregation. Then I tested for each species the effect of competitors on several biological parameters: survival, recruitment, reproduction, body mass, population density. Even though populations' relative distribution was consistent with a mechanism of competitive spatial segregation, with habitat specialists being favored by high-quality, well-connected fragments and generalists exploiting more isolated and degraded patches, results on demographic parameters did not fully confirm this result. The strongest competitive effects were exerted by A. sylvaticus on A. flavicollis, whereas a little degree of interference was found between Apodemus spp. and M. glareolus. Nevertheless, competitive effects were weak, acting on a few biological parameters and not translating into strong effects at the level of populations (density of individuals). These results suggest that populations were mainly distributed according to their ecological requirements; competitive exclusion of specialists from isolated and degraded fragments was actually acting but was likely to play a minor role in determining the observed pattern of distribution. 3) Perceptual range and movement ability of small mammals in fragmented landscapes. The aim of this section was to broaden our understanding of animal orientation and movements in the agricultural matrix, with a special attention on the use of plantation rows as navigation cues. Experiments consisted in releasing individuals of forest-dwelling small mammals (species A. flavicollis, A. sylvaticus, M. glareolus) in fields characterized by different types of matrices: a bare field, a grass field with random pattern of vegetation, and a wheat field at three different stages of growth. Animals (N=119) were marked with fluorescent powder and released at progressive distances from target wood fragments; in this type of experiments individuals are assumed to go directly toward the wood as soon as they perceive it. Animal tracks were then analyzed to determine perceptual ranges and movement abilities. Perceptual ranges were species-specific, with habitat specialists perceiving woods at smaller distances compared to generalists. The presence of vegetation in the fields (either grass or wheat) strongly reduced perceptual ranges of all species by obstructing individuals' view. Furthermore, wheat plantation rows drastically influenced animal movements, possibly facilitating or hampering the reaching of a wood. Individuals of all species, in fact, followed the direction of wheat rows at any stage of growth, even if they were not directed toward the target wood. This study is one of the few examples investigating in detail the demographic mechanisms of response of species to habitat fragmentation. The holistic approach allowed me to provide an overview on the process by which factors such as landscape features, habitat characteristics, and co-occurring species affect the performance of populations in fragmented landscapes. Interspecific interactions play a minor role in shaping the community of small mammals in the studied system. A major role, instead, is played by landscape characteristics (such as habitat cover, connectivity, matrix properties) and local features (such as food resources and habitat structure), in both cases depending on species-specific life-history traits. Increased individual performance (e.g. due to habitat quality) can help to increase the viability of systems of populations; at the same time animals are constrained by the physical structure of the landscape where they live, and individual-scale effects are not necessarily transferred to the level of population. Results suggest that in order to increase the viability of animal systems in fragmented landscapes there is the need to manage the quality of habitat, which proves to be a major determinant of animal populations' performance. Nevertheless, findings also strongly suggest not to ignore the overall landscape context where populations are embedded. In landscapes that have been extensively cleared, restoration aimed to increase the amount of habitat and management of outside-patch landscape elements (hedgerows, agricultural fields) might also be a critical step to ensure the persistence of animal communities

La sindrome cardio-renale: effetti della terapia dello scompenso sulla funzione renale.

Le malattie cardiache e renali sono frequenti e spesso coesistono determinando un significativo aumento di mortalità e morbidità, della difficoltà di gestione del paziente e dei costi sanitari. La stretta correlazione tra patologia renale e cardiovascolare ha suscitato in tempi recenti un rinnovato interesse sulla complessa interazione tra cuore e rene. La sindrome cardio-renale è stata definita come “una disfunzione combinata di cuore e rene in cui l'alterazione acuta o cronica di uno dei due organi può indurre alterazioni acute o croniche anche nell'altro”. Il tempestivo inquadramento di una concomitante disfunzione renale in un paziente con scompenso cardiaco è di fondamentale importanza non solo per il suo impatto prognostico, ma anche perchè l'uso di molti presidi terapeutici comunemente utilizzati per il trattamento dello scompenso aumenta il rischio di eventi avversi. Le evidenze attuali circa gli effetti dei diuretici sulla prognosi dei pazienti con scompenso cardiaco sono limitate e controverse. Lo scopo della tesi è quello di valutare gli effetti renali della terapia nell’ambito di una popolazione affetta da scompenso cardiaco utilizzando l'azotemia e l'escrezione frazionale del sodio come marcatori di insufficienza renale pre-renale. Sono stati esaminati 28 pazienti presso la Medicina di Urgenza Universitaria dell'Azienda Ospedaliera Pisana che sono stati ammessi in reparto con la diagnosi di “scompenso cardiaco”. Giunti in reparto, i pazienti sono stati riesaminati per la diagnosi di scompenso cardiaco mediante i criteri di Framingham maggiori e minori, sono stati valutati con metodica ecocardiocolordoppler e monitorati con esami ematochimici e raccolta urinaria delle 24 ore. I pazienti da noi reclutati erano in numero esiguo per effettuare analisi statistiche significative ma dai dati in nostro possesso è possibile fare alcune considerazioni e pianificare strategie. L'insorgenza della sindrome cardio-renale, non solo si associa ad una cattiva prognosi, ma rende anche molto più complessa la gestione terapeutica del paziente. La disfunzione renale nei pazienti con scompenso cardiaco è frequente e gioca un ruolo cruciale nella cascata di eventi che include la ritenzione idrica e il sovraccarico di volume e che, in ultima analisi, conduce ad aggravamento dello scompenso cardiaco e ad ospedalizzazione e/o morte. E’ per tale motivo che è indispensabile evitare ogni ulteriore compromissione di questo quadro sindromico, soprattutto cercando di gestire al meglio la terapia

Investigating Process Oriented and Product Oriented Worked Examples in an Ill-Structured Learning Domain

Cognitive Load Theory (CLT) research has shown that studying worked examples, which provide a step-by-step solution to a problem, can reduce cognitive load and support learning in well-structured learning domains relative to solving conventional problems. Two types of worked examples that have been widely used in CLT research are process oriented worked examples and product oriented worked examples. Process oriented worked examples provide step-by-step solutions to solve a problem, plus statements explaining the rationale for each step. Product oriented worked examples provide the step-by-step solutions to solve a problem without supporting explanations of each of the steps. In this research two studies were conducted to investigate which instructional condition, process oriented worked examples, product oriented worked examples or conventional problem solving, would best support student learning in an ill-structured learning domain focusing on the quality teaching component of substantive communication

Scalable Facility Location for Massive Graphs on Pregel-like Systems

We propose a new scalable algorithm for facility location. Facility location is a classic problem, where the goal is to select a subset of facilities to open, from a set of candidate facilities F , in order to serve a set of clients C. The objective is to minimize the total cost of opening facilities plus the cost of serving each client from the facility it is assigned to. In this work, we are interested in the graph setting, where the cost of serving a client from a facility is represented by the shortest-path distance on the graph. This setting allows to model natural problems arising in the Web and in social media applications. It also allows to leverage the inherent sparsity of such graphs, as the input is much smaller than the full pairwise distances between all vertices. To obtain truly scalable performance, we design a parallel algorithm that operates on clusters of shared-nothing machines. In particular, we target modern Pregel-like architectures, and we implement our algorithm on Apache Giraph. Our solution makes use of a recent result to build sketches for massive graphs, and of a fast parallel algorithm to find maximal independent sets, as building blocks. In so doing, we show how these problems can be solved on a Pregel-like architecture, and we investigate the properties of these algorithms. Extensive experimental results show that our algorithm scales gracefully to graphs with billions of edges, while obtaining values of the objective function that are competitive with a state-of-the-art sequential algorithm

Activated recombinant factor VIIa should not be used in patients with refractory variceal bleeding: it is mostly ineffective, is expensive, and may rarely cause serious adverse events

Activated Recombinant Factor VIIa Does Not Improve Mortality in Variceal Bleeding. Bendtsen F, D’Amico G, Rusch E, de Franchis R, Anderson PK, Lebrec D, et al. Effect of recombinant Factor VIIa on outcome of acute variceal bleeding: An individual patient based meta-analysis of two controlled trials. J Hepatol 2014; 61: 252–259. (Reproduced with Permission) BACKGROUND & AIMS: Two randomized controlled studies have evaluated the effect of recombinant Factor VIIa (rFVIIa) on variceal bleeding in cirrhosis without showing significant benefit. The aim of the present study was to perform a meta-analysis of the two trials on individual patient data with special focus on high risk patients. METHODS: The primary outcome measure was the effect of rFVIIa on a composite five day endpoint: failure to control bleeding, 5-day rebleeding or death. Analysis was based on intention to treat. High risk was defined as active bleeding on endoscopy while under vasoactive drug infusion and Child-Pugh score >8. RESULTS: 497 patients were eligible for the meta-analysis; 308 (62%) had active variceal bleeding at endoscopy (oozing or spurting) and 283 of these had a Child-Pugh score >8. Analysis on the composite endpoint in all patients with bleeding from oesophageal varices did not show any beneficial treatment effect. However, failure rate for the primary composite end-point was significantly lower in treated patients with active bleeding at endoscopy (17%) compared to placebo (26%, p = 0.049). This difference was highly significant in patients with Child-Pugh score >8 and active bleeding at endoscopy (rFVIIa 16%, placebo 27%; p = 0.023). No significant treatment effect was found at 42 days. Five thromboembolic events occurred in rFVIIa treated patients compared to none in placebo treated patients. CONCLUSIONS: The current meta-analysis shows a beneficial effect of rFVIIa on the primary composite endpoint of control of acute bleeding, prevention of rebleeding day 1–5 and 5-day mortality in patients with advanced cirrhosis and active bleeding from oesophageal varices at endoscopy. A major drawback of the treatment is a potential increased risk of arterial thrombo-embolic events. This treatment might be considered in patients with lack of control of bleeding after standard treatment

EviDense: a Graph-based Method for Finding Unique High-impact Events with Succinct Keyword-based Descriptions

International audienceDespite the significant efforts made by the research community in recent years, automatically acquiring valuable information about high impact-events from social media remains challenging. We present EVIDENSE, a graph-based approach for finding high-impact events (such as disaster events) in social media. Our evaluation shows that our method outper-forms state-of-the-art approaches for the same problem, in terms of having higher precision, lower number of duplicates, while providing a keyword-based description that is succinct and informative

Listing k-cliques in Sparse Real-World Graphs

International audienceMotivated by recent studies in the data mining community which require to efficiently list all k-cliques, we revisit the iconic algorithm of Chiba and Nishizeki and develop the most efficient parallel algorithm for such a problem. Our theoretical analysis provides the best asymptotic upper bound on the running time of our algorithm for the case when the input graph is sparse. Our experimental evaluation on large real-world graphs shows that our parallel algorithm is faster than state-of-the-art algorithms, while boasting an excellent degree of parallelism. In particular, we are able to list all k-cliques (for any k) in graphs containing up to tens of millions of edges as well as all 10-cliques in graphs containing billions of edges, within a few minutes and a few hours respectively. Finally, we show how our algorithm can be employed as an effective subroutine for finding the k-clique core decomposition and an approximate k-clique densest subgraphs in very large real-world graphs