Informed pair selection for self-paced metric learning in Siamese neural networks.

Siamese Neural Networks (SNNs) are deep metric learners that use paired instance comparisons to learn similarity. The neural feature maps learnt in this way provide useful representations for classification tasks. Learning in SNNs is not reliant on explicit class knowledge; instead they require knowledge about the relationship between pairs. Though often ignored, we have found that appropriate pair selection is crucial to maximising training efficiency, particularly in scenarios where examples are limited. In this paper, we study the role of informed pair selection and propose a 2-phased strategy of exploration and exploitation. Random sampling provides the needed coverage for exploration, while areas of uncertainty modeled by neighbourhood properties of the pairs drive exploitation. We adopt curriculum learning to organise the ordering of pairs at training time using similarity knowledge as a heuristic for pair sorting. The results of our experimental evaluation show that these strategies are key to optimising training

Comparative Costs and Returns Pattern of Small-scale Groundnut Milling of RMP-12 and Ex-dakar Varieties in Gombe Metropolis, Gombe State Nigeria

The study determined the costs and returns involved in small-scale groundnut oil processing of two varieties in Gombe metropolis. Twelve markets were purposively selected for their popularity in groundnut oil processing, where 90 processors were selected by simple random sampling technique. Data were collected using structured questionnaires and were analysed using farm budget model, profitability index and t-test analysis. The results revealed that Cost of shelled groundnut constituted the major (92.3% and 91.6%) components of processing costs (P<0.01) for RMP-12 and Ex-dakar respectively. The  gross ratios, fixed ratios and operating ratios of the two groundnut varieties were < 1, meaning that the business was profitable. Also, the returns per naira invested of the respective groundnut varieties was ₦ 0.17 ($0.0006) and ₦ 0.25 ($ 0.0009) significant (P<0.01). Although, the RMP-12 variety gave higher gross income, but the Ex-dakar variety gave higher profit of ₦ 7,428.80 ($ 26.20) per tonne per week (P<0.01). To achieve higher profit, the traders should embark on Ex-dakar variety as the main resource input. They should also have access to formal loans so as to improve productivity and efficiency. Keywords: Comparative costs, Groundnut, Small-scaleJEL Classification: D24; D6

Early clinical predictors and correlates of long-term morbidity in bipolar disorder

OBJECTIVES: Identifying factors predictive of long-term morbidity should improve clinical planning limiting disability and mortality associated with bipolar disorder (BD). METHODS: We analyzed factors associated with total, depressive and mania-related long-term morbidity and their ratio D/M, as %-time ill between a first-lifetime major affective episode and last follow-up of 207 BD subjects. Bivariate comparisons were followed by multivariable linear regression modeling. RESULTS: Total % of months ill during follow-up was greater in 96 BD-II (40.2%) than 111 BD-I subjects (28.4%; P=0.001). Time in depression averaged 26.1% in BD-II and 14.3% in BD-I, whereas mania-related morbidity was similar in both, averaging 13.9%. Their ratio D/M was 3.7-fold greater in BD-II than BD-I (5.74 vs. 1.96; P<0.0001). Predictive factors independently associated with total %-time ill were: [a] BD-II diagnosis, [b] longer prodrome from antecedents to first affective episode, and [c] any psychiatric comorbidity. Associated with %-time depressed were: [a] BD-II diagnosis, [b] any antecedent psychiatric syndrome, [c] psychiatric comorbidity, and [d] agitated/psychotic depressive first affective episode. Associated with %-time in mania-like illness were: [a] fewer years ill and [b] (hypo)manic first affective episode. The long-term D/M morbidity ratio was associated with: [a] anxious temperament, [b] depressive first episode, and [c] BD-II diagnosis. CONCLUSIONS: Long-term depressive greatly exceeded mania-like morbidity in BD patients. BD-II subjects spent 42% more time ill overall, with a 3.7-times greater D/M morbidity ratio, than BD-I. More time depressed was predicted by agitated/psychotic initial depressive episodes, psychiatric comorbidity, and BD-II diagnosis. Longer prodrome and any antecedent psychiatric syndrome were respectively associated with total and depressive morbidity

WISE colours and star-formation in the host galaxies of radio-loud narrow-line Seyfert 1

We investigate the mid-infrared properties of the largest (42 objects) sample of radio-loud narrow-line Seyfert 1 (RL NLS1) collected to date, using data from the Wide-field Infrared Survey Explorer (WISE). We analyse the mid-IR colours of these objects and compare them to what is expected from different combinations of AGN and galaxy templates. We find that, in general, the host-galaxy emission gives an importan contribution to the observed mid-IR flux in particular at the longest wavelengths (W3, at 12micron, and W4, at 22micron). In about half of the sources (22 objects) we observe a very red mid-IR colour (W4-W3>2.5) that can be explained only using a starburst galaxy template (M82). Using the 22micron luminosities, corrected for the AGN contribution, we have then estimated the star-formation rate for 20 of these "red" RL NLS1, finding values ranging from 10 to 500 Msun/y. For the RL NLS1 showing bluer colours, instead, we cannot exclude the presence of a star-forming host galaxy although, on average, we expect a lower star-formation rate. Studying the radio (1.4GHz) to mid-IR (22micron) flux ratios of the RL NLS1 in the sample we found that in ~10 objects the star-forming activity could represent the most important component also at radio frequencies, in addition (or in alternative) to the relativistic jet. We conclude that both the mid-IR and the radio emission of RL NLS1 are a mixture of different components, including the relativistic jet, the dusty torus and an intense star-forming activity.Comment: Accepted for publication in MNRAS, 11 pages, 7 figures, 2 table

Synchronization of Carbohydrate and Protein Supply in the Sugarcane Bagasse Based Ration on in Situ Nutrient Degradability

Two adult male sheeps fitted with rumen cannula were used in two experiments to study the effects of synchronization of carbohydrate and nitrogen supply in sugarcane bagasse based total mixed ration (TMR) on in situ nutrient degradation. The first experiment was aimed to create three TMR with different synchronization index. Ingredient feedstuffs of TMR were evaluated for its in situ organic matter (OM) and nitrogen (N) degradation kinetics. On the basis of the OM and N degradation kinetics of feedstuffs, three sugarcane bagasse based TMR were formulated with synchronization indexes of 0.37; 0.50; and 0.63; respectively. The TMR had similar levels of crude protein (CP), total digestible nutrients, and neutral detergent fiber (NDF). In the second experiment, the three TMR with different synchronization index were evaluated for in situ degradability characteristics of OM, CP, NDF, and sulfur. The in situ degradation of OM in TMR were decreased (P<0.05) with the increasing of synchronization index. The higher synchronization index in TMR increased (P<0.05) CP degradation of CP. The NDF degradation decreased slightly by the alteration of synchronization index in TMR. The higher synchronization index in TMR reduced (P<0.05) in situ sulfur degradation, and this may not support to effects of synchronization of carbohydrate and nitrogen supply

Time-resolved imaging of magnetization dynamics in double nanocontact spin torque vortex oscillator devices

This is the published version. Available from the American Physical Society via the DOI in this recordDouble nanocontact (NC) spin transfer vortex oscillator devices, in which NCs of 100-nm diameter have center-to-center separation ranging from 200 to 1100 nm, have been studied by means of electrical measurements and time-resolved scanning Kerr microscopy (TRSKM). The NCs were positioned close to the edge of the top electrical contact so that the magnetization dynamics of the adjacent region could be probed optically. The electrical measurements showed different ranges of frequency operation for devices with different NC separations. For 900-nm NC separation, TRSKM showed magnetic contrast consistent with the formation of a magnetic vortex at each NC, while for 200-nm NC separation a lack of magnetic contrast near the NC region suggests that the magnetization dynamics occur closer to the NC and underneath the top contact. TRSKM also reveals the presence of additional localized dynamical features far from the NCs, which are not seen by electrical measurements; has not been reported previously for double NCs with different separations; and provides insight into how the dynamic state of the phase-locked oscillators is established and stabilized.Engineering and Physical Sciences Research Council (EPSRC)Ministry of Education, Chile and Commission for Scientific and Technological Research (CONICYT

High-Pressure Phase Diagram in the Manganites: a Two-site Model Study

The pressure dependence of the Curie temperature $T_C$ in manganites, recently studied over a wide pressure range, is not quantitatively accounted for by the quenching of Jahn-Teller distortions, and suggests the occurrence of a new pressure-activated localizing processes. We present a theoretical calculation of $T_C$ based on a two-site double-exchange model with electron-phonon coupling interaction and direct superexchange between the $t_{2g}$ core spins. We calculate the pressure dependence of $T_C$ and compare it with the experimental phase diagram. Our results describe the experimental behavior quite well if a pressure-activated enhancement of the antiferromagnetic superexchange interaction is assumed

Qualitative study in Loop Quantum Cosmology

This work contains a detailed qualitative analysis, in General Relativity and in Loop Quantum Cosmology, of the dynamics in the associated phase space of a scalar field minimally coupled with gravity, whose potential mimics the dynamics of a perfect fluid with a linear Equation of State (EoS). Dealing with the orbits (solutions) of the system, we will see that there are analytic ones, which lead to the same dynamics as the perfect fluid, and our goal is to check their stability, depending on the value of the EoS parameter, i.e., to show whether the other orbits converge or diverge to these analytic solutions at early and late times.Comment: 12 pages, 7 figures. Version accepted for publication in CQ

SDSSJ143244.91+301435.3: a link between radio-loud narrow-line Seyfert 1 galaxies and compact steep-spectrum radio sources?

We present SDSSJ143244.91+301435.3, a new case of radio-loud narrow line Seyfert 1 (RL NLS1) with a relatively high radio power (P1.4GHz=2.1x10^25 W Hz^-1) and large radioloudness parameter (R1.4=600+/-100). The radio source is compact with a linear size below ~1.4 kpc but, contrary to most of the RL NLS1 discovered so far with such a high R1.4, its radio spectrum is very steep (alpha=0.93) and not supporting a 'blazar-like' nature. Both the small mass of the central super-massive black-hole and the high accretion rate relative to the Eddington limit estimated for this object (3.2x10^7 Msun and 0.27, respectively, with a formal error of ~0.4 dex on both quantities) are typical of the class of NLS1. Through a modeling of the spectral energy distribution of the source we have found that the galaxy hosting SDSSJ143244.91+301435.3 is undergoing a quite intense star-formation (SFR=50 Msun y^-1) which, however, is expected to contribute only marginally (~1 per cent) to the observed radio emission. The radio properties of SDSSJ143244.91+301435.3 are remarkably similar to those of compact steep spectrum (CSS) radio sources, a class of AGN mostly composed by young radio galaxies. This may suggest a direct link between these two classes of AGN, with the CSS sources possibly representing the misaligned version (the so-called parent population) of RL NLS1 showing blazar characteristics.Comment: 14 pages, 7 figures, 4 tables, accepted for publication in MNRA

Review of Agricultural Waste Utilization as Improvement Additives for Residual Tropical Soils

The development of a nation partially depends on sustainable materials obtained from agricultural products. Increased agricultural products could increase the amount of waste generated yearly. This paper presents a review on the use of agricultural waste with pozzolanic properties (rice husk ash, Locust bean waste ash, Palm oil fuel&nbsp;ash, Banana leaf ash, Bagasse ash, Coconut shell ash, Bamboo leaf ash, Corn cob ash, Cassava peel ash and Palm kernel shell&nbsp;ash) in various geotechnical engineering applications. Interestingly, these wastes were subjected to various laboratory tests such as (particle size distribution, Compaction, Atterberg, unconfined compressive strength (UCS) and California bearing ratio (CBR)) to assess their effectiveness in soil improvement. In all these, the percentages of the materials required for soil improvement were discussed. The reports from various researchers have shown that agricultural waste having pozzolanic properties improves the engineering properties of soil. For instance, palm oil fuel ash (POFA) is mostly used as an admixture in concrete as reported elsewhere. Few studies have been carried out on the use of banana leaf ash and palm oil fuel ash as soil improvement materials. It is recommended that further researches should focus on the possibility of using other agricultural waste from Cocoyam, Yam peel, maize trunk, Cashew and Guava that have limited reporting researches for use as soil improvement materials