NN^k networks for Content-Based Image Retrieval

This paper describes a novel interaction technique to support content-based image search in large image collections. The idea is to represent each image as a vertex in a directed graph. Given a set of image features, an arc is established between two images if there exists at least one combination of features for which one image is retrieved as the nearest neighbour of the other. Each arc is weighted by the proportion of feature combinations for which the nearest neighbour relationship holds. By thus integrating the retrieval results over all possible feature combinations, the resulting network helps expose the semantic richness of images and thus provides an elegant solution to the problem of feature weighting in content-based image retrieval.We give details of the method used for network generation and describe the ways a user can interact with the structure. We also provide an analysis of the network’s topology and provide quantitative evidence for the usefulness of the technique

Using segmented objects in ostensive video shot retrieval

This paper presents a system for video shot retrieval in which shots are retrieved based on matching video objects using a combination of colour, shape and texture. Rather than matching on individual objects, our system supports sets of query objects which in total reflect the user’s object-based information need. Our work also adapts to a shifting user information need by initiating the partitioning of a user’s search into two or more distinct search threads, which can be followed by the user in sequence. This is an automatic process which maps neatly to the ostensive model for information retrieval in that it allows a user to place a virtual checkpoint on their search, explore one thread or aspect of their information need and then return to that checkpoint to then explore an alternative thread. Our system is fully functional and operational and in this paper we illustrate several design decisions we have made in building it

Cap analysis of gene expression reveals alternative promoter usage in a rat model of hypertension

The role of alternative promoter usage in tissue-specific gene expression has been well established, however, its role in complex diseases is poorly understood. We performed cap analysis of gene expression (CAGE) sequencing from the left ventricle (LV) of a rat model of hypertension, the spontaneously hypertensive rat (SHR), and a normotensive strain, Brown Norway (BN) to understand the role of alternative promoter usage in complex disease. We identified 26,560 CAGE-defined transcription start sites (TSS) in the rat LV, including 1,970 novel cardiac TSSs. We identified 28 genes with alternative promoter usage between SHR and BN, which could lead to protein isoforms differing at the amino terminus between two strains and 475 promoter switching events altering the length of the 5’ UTR. We found that the shift in Insr promoter usage was significantly associated with insulin levels and blood pressure within a panel of HXB/BXH recombinant inbred rat strains, suggesting that hyperinsulinemia due to insulin resistance might lead to hypertension in SHR. Our study provides a preliminary evidence of alternative promoter usage in complex diseases

Private hospital workflow optimization via secure k-means clustering

Optimizing the workflow of a complex organization such as a hospital is a difficult task. An accurate option is to use a real-time locating system to track locations of both patients and staff. However, privacy regulations forbid hospital management to assess location data of their staff members. In this exploratory work, we propose a secure solution to analyze the joined location data of patients and staff, by means of an innovative cryptographic technique called Secure Multi-Party Computation, in which an additional entity that the staff members can trust, such as a labour union, takes care of the staff data. The hospital, owning location data of patients, and the labour union perform a two-party protocol, in which they securely cluster the staff members by means of the frequency of their patient facing times. We describe the secure solution in detail, and evaluate the performance of our proof-of-concept. This work thus demonstrates the feasibility of secure multi-party clustering in this setting

Editorial: Polar genomics in a changing world

Polar regions play critical roles in the function of the Earth’s climate system, many of which are underpinned by their endemic biota. Whilst being home to some of the world’s best-known charismatic megafauna such as polar bears, whales, penguins, seals and albatrosses, polar regions also harbour some of the most poorly explored and least understood biodiversity on the planet (https://www.ipcc.ch/reports, accessed on 9 June 2023). Moreover, these regions are amongst those areas of our planet experiencing the most rapid rates of warming [1,2], resulting in severe threats to their unique ecosystems [3]. With regional warming, the organisms living in these frozen ecosystems will have to adapt if they are to survive, yet we currently have a very limited understanding of polar biodiversity, or indeed of the future resilience of polar organisms in our changing world. To generate a priori predictions of biodiversity change in these regions, it is imperative to understand the true extent of polar biodiversity, including how organisms interact (for example, in food webs), the biological mechanisms by which they have adapted to polar environments, their levels of phenotypic plasticity, and how these attributes may impact their abilities to respond to change. Critical to this understanding are “genomics” approaches that exploit the high-throughput sequencing of genetic material. With the costs of sequencing DNA and RNA having decreased dramatically over recent years, our abilities to probe the genetic code of polar organisms have expanded immeasurably, such that we are now able to answer ecological and evolutionary questions that were intractable even a few years ago, as exemplified by the contributions in this Special Issue on polar genomics

Effects on Oxygen Consumption and Metabolic Gene Expression when Determining Experimental Exercise Intensity Based on Exercise Capacity Tests Conducted in Hypoxic and Normoxic Environments

Abstract: Exercise intensity can be set relative to VO2 max measured during hypoxic or control conditions in studies investigating exercise in hypoxic environments. It currently is not clear which is the most appropriate method. Objective: The objective of this brief report is to determine the response to 1 hour of cycling at 60% of peak power when measured in either normoxic or hypoxic conditions. Methods: Eleven recreationally active male participants (24 ± 4 yrs, 173 ± 20 cm, 82 ± 12 kg, 15.2 ± 7.1% fat, 4.0 ± 0.6 L x min-1 VO2 max) completed two 1 hour cycling exercise trials at 60% of peak power followed by 4 hours of recovery in ambient environmental conditions (975 m) and at normobaric hypoxic conditions simulating 3000 m in a randomized counter balanced order. Results: VO2 max was not different between trials in relative (p=0.272) or absolute terms (p=0.105) but peak power at VO2 max was higher in the 975 m trial (288 ± 17 watts) than the 3000 m trial (262 ± 12 watts, p=0.003) corresponding to differences at 60% of VO2 max power. Gene expression of HIF-1α, COX, PGC-1α, HK, and PFK increased with exercise (p\u3c0.05) but did not differ between trials. There was a trend (p=0.072) toward increased muscle glycogen use in 975m. Conclusions: Although there were not statistical differences for muscle markers in the current study, these data should be considered when determining exercise intensity in hypoxia related research

Inception and propagation of positive streamers in high-purity nitrogen: effects of the voltage rise-rate

Controlling streamer morphology is important for numerous applications. Up to now, the effect of the voltage rise rate was only studied across a wide range. Here we show that even slight variations in the voltage rise can have significant effects. We have studied positive streamer discharges in a 16 cm point-plane gap in high-purity nitrogen 6.0, created by 25 kV pulses with a duration of 130 ns. The voltage rise varies by a rise rate from 1.9 kV/ns to 2.7 kV/ns and by the first peak voltage of 22 to 28 kV. A structural link is found between smaller discharges with a larger inception cloud caused by a faster rising voltage. This relation is explained by the greater stability of the inception cloud due to a faster voltage rise, causing a delay in the destabilisation. Time-resolved measurements show that the inception cloud propagates slower than an earlier destabilised, more filamentary discharge. This explains that the discharge with a faster rising voltage pulse ends up to be shorter. Furthermore, the effect of remaining background ionisation in a pulse sequence has been studied, showing that channel thickness and branching rate are locally affected, depending on the covered volume of the previous discharge.Comment: 16 pages, 9 figure

Latitudinal trends in stable isotope signatures and carbon-concentrating mechanisms of northeast Atlantic rhodoliths

Rhodoliths are free-living calcifying red algae that form extensive beds in shallow marine benthic environments (&lt;250&thinsp;m), which provide important habitats and nurseries for marine organisms and contribute to carbonate sediment accumulation. There is growing concern that these organisms are sensitive to global climate change, yet little is known about their physiology. Considering their broad distribution along most continental coastlines, their potential sensitivity to global change could have important consequences for the productivity and diversity of benthic coastal environments. The goal of this study was to determine the plasticity of carbon-concentrating mechanisms (CCMs) of rhodoliths along a latitudinal gradient in the northeast Atlantic using natural stable isotope signatures. The δ13C signature of macroalgae can be used to provide an indication of the preferred inorganic carbon source (CO2 vs. HCO3−). Here we present the total (δ13CT) and organic (δ13Corg) δ13C signatures of northeast Atlantic rhodoliths with respect to changing environmental conditions along a latitudinal gradient from the Canary Islands to Spitsbergen. The δ13CT signatures (−11.9 to −0.89) of rhodoliths analyzed in this study were generally higher than the δ13Corg signatures, which ranged from −25.7 to −2.8. We observed a decreasing trend in δ13CT signatures with increasing latitude and temperature, while δ13Corg signatures were only significantly correlated to dissolved inorganic carbon. These data suggest that high-latitude rhodoliths rely more on CO2 as an inorganic carbon source, while low-latitude rhodoliths likely take up HCO3− directly, but none of our specimens had ∂13Corg signatures less than −30, suggesting that none of them relied solely on diffusive CO2 uptake. However, depth also has a significant effect on both skeletal and organic δ13C signatures, suggesting that both local and latitudinal trends influence the plasticity of rhodolith inorganic carbon acquisition and assimilation. Our results show that many species, particularly those at lower latitudes, have CCMs that facilitate HCO3− use for photosynthesis. This is an important adaptation for marine macroalgae, because HCO3− is available at higher concentrations than CO2 in seawater, and this becomes even more extreme with increasing temperature. The flexibility of CCMs in northeast Atlantic rhodoliths observed in our study may provide a key physiological mechanism for potential adaptation of rhodoliths to future global climate change.</p