An Axiomatic Analysis of Diversity Evaluation Metrics: Introducing the Rank-Biased Utility Metric

Many evaluation metrics have been defined to evaluate the effectiveness ad-hoc retrieval and search result diversification systems. However, it is often unclear which evaluation metric should be used to analyze the performance of retrieval systems given a specific task. Axiomatic analysis is an informative mechanism to understand the fundamentals of metrics and their suitability for particular scenarios. In this paper, we define a constraint-based axiomatic framework to study the suitability of existing metrics in search result diversification scenarios. The analysis informed the definition of Rank-Biased Utility (RBU) -- an adaptation of the well-known Rank-Biased Precision metric -- that takes into account redundancy and the user effort associated to the inspection of documents in the ranking. Our experiments over standard diversity evaluation campaigns show that the proposed metric captures quality criteria reflected by different metrics, being suitable in the absence of knowledge about particular features of the scenario under study.Comment: Original version: 10 pages. Preprint of full paper to appear at SIGIR'18: The 41st International ACM SIGIR Conference on Research & Development in Information Retrieval, July 8-12, 2018, Ann Arbor, MI, USA. ACM, New York, NY, US

Exhumed Fluvial Deposits: New Paleohydrological Tools Indicate Long-Duration Fluvial Activity on Early Mars

Fluvial sinuous ridges are common landforms on Mars that have been used for interpreting the history of ancient martian rivers. They are typically interpreted as eroded casts of an ancient river at a snapshot in time. However, some ridges might instead be channel belts that preserve river history, leading to significant differences in interpretation of paleohydrology, including flow direction, duration, and discharge. In this thesis, I used analog sites on Earth and techniques from fluvial sedimentology and fluvial geomorphology to determine that many ridges are exhumed channel belts, and to create and apply new tools for measuring bankfull discharge and duration of river flow from remote-sensing observations of these sedimentary deposits. I found evidence that rivers on ancient Mars were comparable in size to those on Earth today, and that they flowed for at least millions of years. I examined sinuous ridges in three terrestrial sites to better understand ridges on Mars: the Cretaceous Cedar Mountain Formation and Jurassic Morrison Formation of Eastern Utah, and the Miocene Caspe Formation of Northeast Spain. Ridges at all sites are capped with sandy units rich with dune and bar strata atop a mudstone pedestal and they cross each other at different stratigraphic levels, observations that together indicate that ridges are channel belts exhumed from floodplain sediments — the most common arrangement of fluvial stratigraphy. By compiling measurements of hundreds of terrestrial channel belts and their associated channels, I found that the best methods to reconstruct paleochannel bankfull geometry from such deposits are to use thickness of channel belts (1-4 times paleochannel depth) or radius of curvature of lateral accretion sets (half the channel width). Ridge width and planview wavelength, common proxies for paleochannel width, are significantly more uncertain due to channel amalgamation and ridge erosion by scarp retreat, which I quantified with geometry and a new erosion model. Intermittency factor converts bankfull discharge to average discharge, enabling measurement of duration of river flow. I calculated the intermittency factor for 206 fluvial deposits and USGS streamgages, and found that it ranges between 0.003-0.7 with a median of 0.10, with values depending on the ratio of catchment-averaged erosion rate to average precipitation but independent of timescale, river size, climate, or grainsize. Throughout the work, I applied the methods to sinuous ridges on Mars to demonstrate their applicability. I found that many ridges are likely channel belts, and that the ancient rivers they represent are likely smaller but longer than previously studies have indicated. Altogether, this contribution enables new quantitative analyses of ancient rivers on Earth and Mars, and provides evidence that ancient Martian climate was capable of supporting liquid water at many locations across the surface for at least millions of years.</p

Modelling the Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) site index from site factors in Portugal

Although the speed of growth and adaptability of the north-west American conifer Douglas-fir has been recognized in Portugal, it represents only ~0.1 per cent of the total forest cover. This small area is spread across the mountainous areas of the north and centre of the country. This study models Douglas-fir productivity based on site factors and estimates the potential area for Douglas-fir in Portugal. Soil, climate and topographic data were collected on 39 plots across the range of sites where Douglas-fir grows in Portugal. The analysis of the data followed three steps: (1) selection of site factors related to the variation in the site index; (2) choice of candidate models; and (3) consideration of the best model to explain and predict the site index from site factor variables. The best multiple linear regression model explained 90 per cent of site index variation but included variables not readily available in the field. A model using digitized site data explained 54 per cent of the variation in the site index and mapped the areas with potential for Douglas-fir growth in Portugal. It is estimated that a potential Douglas-fir planting area of 250 000 ha exists where trees will exceed 17 m dominant height at age 30 years. This would correspond to 8 per cent of the existing Portuguese forest area. The best sites for Douglas-fir growth are located along north coastal to central regions at altitudes between 500 m and 1000 m with moisture deficit (precipitation minus evapotranspiration) above 1000 mm. Areas with acceptable sites for Douglas-fir growth are located in the north and centre of Portugal at 700–1000 m elevation and have a moisture deficit above 400 mminfo:eu-repo/semantics/publishedVersio

Geothermal Heating and its Influence on the Meridional Overturning Circulation

The effect of geothermal heating on the meridional overturning circulation is examined using an idealized, coarse-resolution ocean general circulation model. This heating is parameterized as a spatially uniform heat flux of 50 mW m-2 through the (flat) ocean floor, in contrast with previous studies that have considered an isolated hotspot or a series of plumes along the mid-Atlantic ridge. The equilibrated response is largely advective: a deep perturbation of the meridional overturning cell on the order of several Sv is produced, connecting with an upper-level circulation at high latitudes, allowing the additional heat to be released to the atmosphere. Risingmotion in the perturbation deep cell is concentrated near the equator. The upward penetration of this cell is limited by the thermocline, analogous to the role of the stratosphere in limiting the upward penetration of convective plumes in the atmosphere. The magnitude of the advective response is inversely proportional to the deep stratification; with a weaker background meridional overturning circulation and a less stratified abyss, the overturning maximum of the perturbation deep cell is increased. This advective response also cools the low-latitude thermocline. The qualitative behavior is similar in both a single hemisphere and double hemisphere configuration.The anomalous circulation driven by geothermal fluxes is more substantial than previously thought. We are able to understand the structure and strength of the response in the idealized geometry and further extend these ideas to explain the results of Adcroft et al. [2001], where the impact of geothermal heating was examined using a global configuration

Defining the pig microglial transcriptome reveals its core signature, regional heterogeneity, and similarity with human and rodent microglia:Pig microglial transcriptome signature

Microglia play key roles in brain homeostasis as well as responses to neurodegeneration and neuroinflammatory processes caused by physical disease and psychosocial stress. The pig is a physiologically relevant model species for studying human neurological disorders, many of which are associated with microglial dysfunction. Furthermore, pigs are an important agricultural species, and there is a need to understand how microglial function affects their welfare. As a basis for improved understanding to enhance biomedical and agricultural research, we sought to characterize pig microglial identity at genome-wide scale and conduct inter-species comparisons. We isolated pig hippocampal tissue and microglia from frontal cortex, hippocampus, and cerebellum, as well as alveolar macrophages from the lungs and conducted RNA-sequencing (RNAseq). By comparing the transcriptomic profiles between microglia, macrophages, and hippocampal tissue, we derived a set of 239 highly enriched genes defining the porcine core microglial signature. We found brain regional heterogeneity based on 150 genes showing significant (adjusted p < 0.01) regional variations and that cerebellar microglia were most distinct. We compared normalized gene expression for microglia from human, mice and pigs using microglia signature gene lists derived from each species and demonstrated that a core microglial marker gene signature is conserved across species, but that species-specific expression subsets also exist. Our data provide a valuable resource defining the pig microglial transcriptome signature that validates and highlights pigs as a useful large animal species bridging between rodents and humans in which to study the role of microglia during homeostasis and disease

Unloading shoes for intermittent claudication: a randomised crossover trial

Background: The purpose of this study was to assess the functional effects and acceptability of rocker-soled shoes that were designed to relatively “unload” the calf muscles during walking in people with calf claudication due to peripheral arterial disease. Methods: In this randomised AB/BA crossover trial, participants completed two assessment visits up to two weeks apart. At each visit, participants completed walking tests whilst wearing the unloading shoes or visually-similar control shoes. At the end of the second visit, participants were given either the unloading or control shoes to use in their home environment for 2 weeks, with the instruction to wear them for at least 4 hours every day. The primary outcome was 6-minute walk distance. We also assessed pain-free walking distance and gait biomechanical variables during usual-pace walking, adverse events, and participants’ opinions about the shoes. Data for continuous outcomes are presented as mean difference between conditions with corresponding 95% confidence interval. Results: Thirty-four participants (27 males, mean age 68 years, mean ankle-brachial index 0.54) completed both assessment visits. On average, the 6-minute walk distance was 11 m greater when participants wore the control shoes (95% CI -5 to 26), whereas mean pain-free walking distance was 7 m greater in the unloading shoes (95% CI -17 to 32). Neither of these differences were statistically significant (p=0.18 and p=0.55, respectively). This was despite the unloading shoes reducing peak ankle plantarflexion moment (mean difference 0.2 Nm/kg, 95% CI 0.0 to 0.3) and peak ankle power generation (mean difference 0.6 W/kg, 95% CI 0.2 to 1.0) during pain-free walking. The survey and interview data was mixed, with no clear differences between the unloading and control shoes. Conclusions: Shoes with modified soles to relatively unload the calf muscles during walking conferred no substantial acute functional benefit over control shoes

The citric acid cough threshold and the ventilatory response to carbon dioxide on ascent to high altitude

SummaryVentilatory control undergoes profound changes on ascent to high altitude. We hypothesized that the fall in citric acid cough threshold seen on ascent to altitude is mediated by changes in the central control of cough and would parallel changes in central ventilatory control assessed by the hypercapnic ventilatory response (HCVR). Twenty-five healthy volunteers underwent measurements of HCVR and citric acid sensitivity at sea level and during a 9 day sojourn at 5200m. None of the subjects had any evidence of respiratory infection. Citric acid cough threshold fell significantly on ascent to 5200m. The slope, S, of the HCVR increased significantly on ascent to 5200m and during the stay at altitude. There was no correlation between citric acid sensitivity and HCVR. We conclude that the change in citric acid cough threshold seen on exposure to hypobaric hypoxia is unlikely to be mediated by changes in the central control of cough. Sensitivity to citric acid may be due to early subclinical pulmonary edema stimulating airway sensory nerve endings

An Early Beaker funerary monument at Porton Down, Wiltshire

Excavation of an Early Beaker-Early Bronze Age funerary monument at Porton Down revealed an unusually complex burial sequence of 12 individuals, spanning four centuries, including eight neonates or infants and only one probable male, surrounded by a segmented ring-ditch. In the centre was a large grave which contained the disturbed remains of an adult female, accompanied by a Beaker, which had probably been placed within a timber chamber and later ‘revisited’ on one or more occasions. This primary burial and an antler pick from the base of the ring-ditch provided identical Early Beaker radiocarbon dates. Two burials were accompanied by a Food Vessel and a miniature Collared Urn respectively, others were unaccompanied, and there was a single and a double cremation burial, both within inverted Collared Urns. A C-shaped enclosure nearby may have been contemporary with the funerary monument, but its date and function are uncertain. Other features included an Early Neolithic pit which contained a significant assemblage of worked flint, and several Middle Bronze Age ditches and a Late Bronze Age ‘Wessex Linear’ ditch that reflect later prehistoric land divisions probably related to stock control

Breast cancer risk reduction:is it feasible to initiate a randomised controlled trial of a lifestyle intervention programme (ActWell) within a national breast screening programme?

BackgroundBreast cancer is the most commonly diagnosed cancer and the second cause of cancer deaths amongst women in the UK. The incidence of the disease is increasing and is highest in women from least deprived areas. It is estimated that around 42% of the disease in post-menopausal women could be prevented by increased physical activity and reductions in alcohol intake and body fatness. Breast cancer control endeavours focus on national screening programmes but these do not include communications or interventions for risk reductionThis study aimed to assess the feasibility of delivery, indicative effects and acceptability of a lifestyle intervention programme initiated within the NHS Scottish Breast Screening Programme (NHSSBSP).MethodsA 1:1 randomised controlled trial (RCT) of the 3 month ActWell programme (focussing on body weight, physical activity and alcohol) versus usual care conducted in two NHSSBSP sites between June 2013 and January 2014. Feasibility assessments included recruitment, retention, and fidelity to protocol. Indicative outcomes were measured at baseline and 3 month follow-up (body weight, waist circumference, eating and alcohol habits and physical activity. At study end, a questionnaire assessed participant satisfaction and qualitative interviews elicited women¿s, coaches and radiographers¿ experiences. Statistical analysis used Chi squared tests for comparisons in proportions and paired t tests for comparisons of means. Linear regression analyses were performed, adjusted for baseline values, with group allocation as a fixed effectResultsA pre-set recruitment target of 80 women was achieved within 12 weeks and 65 (81%) participants (29 intervention, 36 control) completed 3 month assessments. Mean age was 58¿±¿5.6 years, mean BMI was 29.2¿±¿7.0 kg/m2 and many (44%) reported a family history of breast cancer.The primary analysis (baseline body weight adjusted) showed a significant between group difference favouring the intervention group of 2.04 kg (95%CI ¿3.24 kg to ¿0.85 kg). Significant, favourable between group differences were also detected for BMI, waist circumference, physical activity and sitting time. Women rated the programme highly and 70% said they would recommend it to others.ConclusionsRecruitment, retention, indicative results and participant acceptability support the development of a definitive RCT to measure long term effects.Trial registrationThe trial was registered with Current Controlled Trials (ISRCTN56223933)