Miracle-dz/UniFAR-FTUs huggingface dataset:
Statistics and geometry of cosmic voids

We introduce new statistical methods for the study of cosmic voids, focusing on the statistics of largest size voids. We distinguish three different types of distributions of voids, namely, Poisson-like, lognormal-like and Pareto-like distributions. The last two distributions are connected with two types of fractal geometry of the matter distribution. Scaling voids with Pareto distribution appear in fractal distributions with box-counting dimension smaller than three (its maximum value), whereas the lognormal void distribution corresponds to multifractals with box-counting dimension equal to three. Moreover, voids of the former type persist in the continuum limit, namely, as the number density of observable objects grows, giving rise to lacunar fractals, whereas voids of the latter type disappear in the continuum limit, giving rise to non-lacunar (multi)fractals. We propose both lacunar and non-lacunar multifractal models of the cosmic web structure of the Universe. A non-lacunar multifractal model is supported by current galaxy surveys as well as cosmological N-body simulations. This model suggests, in particular, that small dark matter halos and, arguably, faint galaxies are present in cosmic voids.
Trash to treasure: leaf-cutting ants repair nest-mound damage by recycling refuse dump materials

Animals adjust their behaviors in response to changing environmental conditions because the costs and benefits of such behaviors change as conditions change. The reuse of materials from waste (i.e., recycling) rarely occurs in social insects because it may imply significant health risks and behavioral difficulties. However, the benefit of reusing may exceed its costs under certain circumstances. For the first time, we document that ants "recycle" refuse materials to repair nest-mound damage. We conducted a series of field measurements and experiments to test the hypotheses that fluctuations in this behavior in the leaf-cutting ant Acromyrmex lobicornis depend on 1) seasonal changes in the tendency to reject refuse (a proxy of changes in their pathogen levels), and/or 2) seasonal foraging restrictions. We 1) measured the rejection of foraging ants toward experimental refuse piles among seasons and 2) analyzed how mound condition, temperatures of fungus chamber and soil surface, and foraging activity explained this behavior using a classification tree, a powerful recursive partitioning method. Foraging ants showed similar rejection levels toward refuse piles in different seasons. Colonies repaired mound damage with refuse materials only during the hottest season and when they had low foraging rates, suggesting that ants recycle their refuse by a hierarchical set of decisions dependent on the risk of fungal damage and foraging restrictions. Repairing the mounds is essential during summer, when temperatures inside damaged mounds are lethal to their fungus cultures. However, these high temperatures also restrict the foraging activity, reducing the collection of building materials. Thus, colonies with lower foraging rates apparently use their refuse to repair mounds because this substrate requires less searching and carrying time. The use of refuse did not affect the colony growth rate. This illustrates how ants integrate information about food, hygienic and nest conditions through a novel and plastic behavior: recycling of their discarded materials.
Verification Platform for Plant AVC Substations based on Digital Simulation Technology

Generator automatic voltage control device (AVC) is an automatic voltage and reactive power optimization control terminal on the power plant side. Aiming at improving the performance of generator automatic voltage control device, this paper introduces a detection method of AVC substation performance based on virtual dispatching terminal environment. During the testing, the upper computer of redundant power plant is connected to the virtual dispatching terminal environment to simulate the sending instructions of AVC master station, the behavior of AVC sub stations and the excitation system of generators. The performance of AVC substation is evaluated according to the feedback adjustment results, which can effectively detect the abnormal behavior of AVC substation in power plant.
Oxygen Effects in Anaerobic Digestion Deshai Botheju

Free oxygen effects in bio-gasification are not well known, apart from the common understanding of oxygen being toxic and inhibitory for anaerobic micro-organisms. Some studies have, however, revealed increased solubilisation of organic matter in the presence of some free oxygen in anaerobic digestion. This article analyses these counterbalancing phenomena with a mathematical modelling approach using the widely accepted biochemical model ADM 1. Aerobic oxidation of soluble carbon and inhibition of obligatory anaerobic organisms are modelled using standard saturation type kinetics. Biomass dependent first order hydrolysis kinetics is used to relate the increased hydrolysis rate with oxygen induced increase in biomass growth. The amended model, ADM 1-Ox (oxygen), has 25 state variables and 22 biochemical processes, presented in matrix form. The computer aided simulation tool AQUASIM 2.1 is used to simulate the developed model. Simulation predictions are evaluated against experimental data obtained using a laboratory batch test array comprising miniature anaerobic bio-reactors of 100 ml total volume each, operated under different initial air headspaces giving rise to the different oxygen loading conditions. The reactors were initially fed with a glucose solution and incubated at 35  for 563 hours. Under the oxygen load conditions of 22, 44 and 88 mg/L, the ADM1-Ox model simulations predicted the experimental methane potentials quite adequately. Both the experimental data and the simulations suggest a linear reduction of methane potential with respect to the increase in oxygen load within this range.
Pan-Arctic and Regional Sea Ice Predictability: Initialization Month Dependence

AbstractSeasonal-to-interannual predictions of Arctic sea ice may be important for Arctic communities and industries alike. Previous studies have suggested that Arctic sea ice is potentially predictable but that the skill of predictions of the September extent minimum, initialized in early summer, may be low. The authors demonstrate that a melt season “predictability barrier” and two predictability reemergence mechanisms, suggested by a previous study, are robust features of five global climate models. Analysis of idealized predictions with one of these models [Hadley Centre Global Environment Model, version 1.2 (HadGEM1.2)], initialized in January, May and July, demonstrates that this predictability barrier exists in initialized forecasts as well. As a result, the skill of sea ice extent and volume forecasts are strongly start date dependent and those that are initialized in May lose skill much faster than those initialized in January or July. Thus, in an operational setting, initializing predictions of .
Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

Abstract. In this work, the Aerodyne soot particle – aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m−3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ∼ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (
Sky Flats: Generating Improved WFC3 IR Flat-fields

A significantly improved set of flat-fields are now available and are currently used as part of the WFC3 calibration pipeline. We describe the creation and testing of new in-orbit flat-field corrections for the WFC3 IR channel. While high signal to noise ground based flat-fields were generated prior to launch, photometry of dithered stellar fields showed that these flat-fields failed to fully flatten the large scale structure of the WFC3 IR flat-fields. In this ISR we show how we generated a correction to the ground based flat-fields using thousands of IR observations. This correction, or sky delta flat-field (SD-flat in this ISR), appears to be both wavelength and time independent and is stable down to better than 1% over most of the detector. Photometric accuracy using new corrected flat-fields is better than 0.5% (peak to peak variation of -1.5/+1.6%) if one avoid being within 128 pixels of the edge of the detector. For the “wagon-wheel” region and the edge of the detector, photometric accuracy is reduced to about 0.8% (peak to peak variation of -2.0/+1.9%).
Investigating the Applicability of Lehman’s Laws of Software Evolution using Metrics: An Empirical Study on Open Source Software

This paper aims at investigating empirically the applicability of Lehman’s laws of software evolution using software metrics. We used a synthetic metric (Quality Assurance Indicator Qi), which captures in an integrated way different object-oriented software attributes. We wanted to investigate if the Qi metric can be used to support the applicability of Lehman’s laws of software evolution. We focused on the laws related with continuing change, increasing complexity, continuing growth and declining quality. We performed an empirical analysis using historical data on two open source (Java) software systems. The collected data cover a period of more than four years (fifty-two versions) for the first system and more than seven years (thirty-one versions) for the second one. Empirical results provide evidence that the considered Lehman’s laws are supported by the collected data and the Qi metric.
Celebrity Firms: The Social Construction Of Market Popularity

We extend the concept of celebrity from the individual to the firm level of analysis and argue that the high level of public attention and the positive emotional responses that define celebrity increase the economic opportunities available to a firm. We develop a theoretical framework explaining how the media construct firm celebrity by creating a "dramatized reality" in reporting on industry change and firms' actions. Firms contribute to this process by taking nonconforming actions and proactively seeking to manage impressions about themselves. [ABSTRACT FROM AUTHOR]
Implementation of Artificial Intelligence Methods for Virtual Reality Solutions : a Review of the Literature

Today, Artificial Intelligence (AI) used widely in data science and computer vision. It has proven to be state of the art algorithm for classification tasks. One of the tasks that Virtual reality often solves can be specified as object recognition or classification. These types of tasks benefit from automatic feature detector provided by convolutional neural networks (CNN). This article investigates and provides a practical guide on implementing AI methods for object recognition and skeleton recognition to show practical solutions on the given tasks for
A SEISMIC DATA ANALYSIS CONSOLE

Abstract : A software system for a PDP-7 digital computer with a cathode ray tube display has been designed to process seismic data. The system permits quick visual inspection of digitized data and allows easy application of powerful programs which operate on the digitized data or on the results of previously used programs. Some operations which can be performed are: epicenter location, beamforming, magnitude, complexity and spectral ratio computation, filtering autocorrelation, Fourier transformation, sonogram generation and automatic event detection. A human operator is in the processing loop, inspecting the output at each step before applying the next. This system has greatly increased the speed and efficiency of much of our seismic data processing.
The evolution of H ii galaxies: testing the bursting scenario through the use of self-consistent models

We have computed a series of realistic and self-consistent models of the emitted spectra of H ii galaxies. Our models combine different codes of chemical evolution, evolutionary population synthesis and photoionization. The emitted spectrum of H ii galaxies is reproduced by means of the photoionization code cloudy, using as ionizing spectrum the spectral energy distribution of the modelled H ii galaxy, which in turn is calculated according to a star formation history and a metallicity evolution given by a chemical evolution model that follows the abundances of 15 different elements. The contribution of emission lines to the broad-band colours is explicitly taken into account. The results of our code are compared with photometric and spectroscopic data of H ii galaxies. Our technique reproduces observed diagnostic diagrams, abundances, equivalent width–colour and equivalent width–metallicity relations for local H ii galaxies.
A Simple Method for Delineation of Leachate Plumes

Measurement and calculation of the carbon isotopic composition of groundwater from piezometers located around a reclaimed landfill were performed in order to test the method to distinguish the piezometers localized within the contaminated area and to identify the boundaries of the leachate plume. In order to select the best method for delineation of the leachate plume it was analyzed: chemical composition, the stable carbon isotopic composition in groundwater, and the calculation of carbon isotopic composition in groundwater. Comparison of the different methods for delineation of the leachate plume indicate, that the best method appear to be method based on the measurement and calculation of the carbon isotopic composition in groundwater. The proposed method has been tested using the data from Otwock landfill (Poland), but it can also be used in other contaminated areas.
Identifying in situ climate refugia for plant species

Identification of refugia from climate change is increasingly considered important for biodiversity conservation, but the distribution of putative refugia may vary across alternative climate scenarios, impeding conservation decision-making. Based on 117 plant species representative of ecoregions within south-eastern Australia, we provide a case study identifying in situ refugia across a spectrum of plausible future climates. We define in situ refugia as areas that currently contain populations of the target species, and are projected to remain climatically suitable in the future. Refugia were identified across scenarios describing futures that are, relative to 1990–2009, warmer and wetter, warmer/drier, hotter/wetter, and hotter with little precipitation change. Despite substantial variation in the spatial extent and longevity of climate refugia across species, ecoregions and climate scenarios, clear patterns emerged. By 2070, refugia for species in 1) deserts and xeric shrublands; 2) mediterranean forests, woodlands and shrublands; and 3) temperate and tropical grasslands are likely to be least extensive under a hotter/ wetter future. Conversely, wetter conditions may lead to broader refugia for species in temperate forests. We identified areas of congruence where high richness refugia (refugia for  50% of representative species) were projected to occur irrespective of the climate scenario. These regions therefore appear robust to uncertainty about climate change, presenting clear targets for conservation attention. Our approach provides valuable information for decision-makers, enabling them to identify and visualise the spatial arrangement of refugia under contrasting scenarios of environmental change. This reveals management options in the context of climate uncertainty and facilitates informed prioritisation of conservation resources.
Why don ’ t less educated workers move ? The role of job search in migration decisions

I establish a new stylised fact showing that less educated workers are not only less mobile, they are also significantly less likely to move with a job in hand. Using evidence based on US panel data, I argue that a large portion of the observed differences in migration behaviour is driven by the differences in workers’ employment options in other regions. Compared to college graduates, less educated workers find job search in more distant regions much more difficult. This limits their options to move for guaranteed employment, forcing them to move speculatively, and thereby reducing their overall mobility. I develop these results in two stages. First, I adapt the recent literature from empirical IO on discrete choice models with heteregeneous option sets to isolate the impact of differences in employment opportunities on migration decisions. Second, I extend the standard model of job search (McCall (1970)) to multiple residential locations. I estimate this model to quantify the size of cross-regional job search frictions, finding that they can explain approximately half of the migration propensity gap between the more and the less educated. This result opens a new policy channel in addressing regional differences and those left behind: the importance of the ability to find a job before moving suggests a large social return to improving regional search and matching for less educated groups. ∗maria.balgova@ccc.ox. ac.uk. Department of Economics, University of Oxford. I am indebted to my supervisors Margaret Stevens and Abi Adams for their guidance and encouragement. I would also like to thank Steve Bond, Tony Venables, Peter Neary, Simon Quinn, Ian Crawford, Jean Flemming, Alex Plekhanov, and the conference and seminar participants at the Search and Matching Conference (University of Cambridge), Oxford Applied Micro Seminar, Royal Economic Society Symposium (University of Sussex), and ZEW Summer School (Mannheim) for advice and comments. This work would not be possible without the generous support of ESRC and Wolf Scholarship (Corpus Christi College).
SURVEY OF “CANDIDATUS LIBERIBACTER SOLANACEARUM” IN CARROT CROPS AFFECTED BY THE PSYLLID TRIOZA APICALIS (HEMIPTERA: TRIOZIDAE) IN NORWAY

SUMMARY The carrot psyllid Trioza apicalis Forster (Hemiptera: Triozidae) is a serious insect pest of carrot (Daucus carota L.) in northern Europe, where it can cause up to 100% crop loss. Although it was long believed that T. apicalis causes damage to carrot by injection of toxins into the plant, it was recently established that this psyllid is a vector of the new bacterium “Candidatus Liberibacter solanacearum”, which severely damages carrot crops. This bacterium is also known to severely affect solanaceous crops and is the causal agent of zebra chip, a new and economically important disease of potato in North and Central America and New Zealand. Symptoms in psyllid-affected carrots include leaf curling, yellowish and purplish discoloration of the leaves, stunted growth of both leaves and roots, and proliferation of secondary roots. These plant symptoms resemble those caused by leafhoppertransmitted phytoplasmas and Spiroplasma citri in carrots. Using PCR assays, a survey of “Ca. L. solanacearum” in carrot crops in Norway determined that the bacterium is widespread in several counties in southeastern and eastern Norway, where most of the carrot crops are grown. Liberibacter infection rate ranged from 33.3 to 100% in carrot plants and from 21.2 to 56.3% in T. apicalis. No phytoplasmas or spiroplasmas were detected in carrot or psyllid samples by PCR. Information from this research will help carrot producers reduce damage caused by “Ca. L. solanacearum” to carrot crops by vigorously monitoring and controlling T. apicalis, its insect vector.
A Service System with Packing Constraints: Greedy Randomized Algorithm Achieving Sublinear in Scale Optimality Gap

A service system with multiple types of arriving customers is considered. There is an infinite number of homogeneous servers. Multiple customers can be placed for simultaneous service into one server, subject to general packing constraints. Each new arriving customer is placed for service immediately, either into an occupied server, as long as packing constraints are not violated, or into an empty server. After service completion, each customer leaves its server and the system. The basic objective is to minimize the number of occupied servers in steady state. We study a Greedy-Random (GRAND) placement (packing) algorithm, introduced in [23]. This is a simple online algorithm, which places each arriving customer uniformly at random into either one of the already occupied servers that can still fit the customer, or one of the so-called zero-servers, which are empty servers designated to be available to new arrivals. In [23], a version of the algorithm, labeled GRAND($aZ$), was considered, where the number of zero servers is $aZ$, with $Z$ being the current total number of customers in the system, and $a>0$ being an algorithm parameter. GRAND($aZ$) was shown in [23] to be asymptotically optimal in the following sense: (a) the steady-state optimality gap grows linearly in the system scale $r$ (the mean total number of customers in service), i.e. as $c(a) r$ for some $c(a)> 0$; and (b) $c(a) \to 0$ as $a\to 0$. In this paper, we consider the GRAND($Z^p$) algorithm, in which the number of zero-servers is $Z^p$, where $p \in (1-1/(8\kappa),1)$ is an algorithm parameter, and $(\kappa-1)$ is the maximum possible number of customers that a server can fit. We prove the asymptotic optimality of GRAND($Z^p$) in the sense that the steady-state optimality gap is $o(r)$, sublinear in the system scale. This is a stronger form of asymptotic optimality than that of GRAND($aZ$).