cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Technical efficiency analysis and decomposition of productivity growth of Spanish olive farms
Creators: name: Lambarraa, Fatima
name: Serra, Teresa
name: Gil Roig, Jose Maria
name: Lambarraa, Fatima
name: Serra, Teresa
name: Gil Roig, Jose Maria
Publisher: name: Unknown
Year: 2006
Subjects: Crop Production/Industries
Productivity Analysis

description: The concept of technical efficiency is critical to measuring the firm performance, determining the degree of innovative technology adoption and the overall production efficiency. Traditionally, technical efficiency has been measured as the ratio of observed output to maximum feasible output. Stochastic frontier models have been widely utilized to assess this issue. Our research evaluates technical efficiencies in the Spanish olive sector. Specifically, the main objective of this study is to estimate a stochastic frontier production model by using a farm- level panel of data. The non- negative technical efficiency effects are assumed to be a function of firm- specific variables. A sample of Spanish farms observed from 1999 to 2002 is obtained from the FADN dataset and used in the estimation of the model. Maximum- likelihood methods are applied in the estimation of the parameters of the model. A primal approach is used to decompose Total Factor Productivity (TFP) growth. Results indicate that farm location, age of manager, tenure regimes of land and whether the farm has adopted organic farming techniques affect efficiency levels . Technical efficiency change, allocative efficiencies and scale effects are found to be the main sources of TFP growth, while technical change seems to be of minor importance. Results also suggest that Spanish olive farms are less efficient relative to other EU farms. This suggests that improvements in the Spanish olive productive capacity after the accession to the EU were not fully implemented in the period of analysis. This may be due to a decline in olive farm incomes as a result of a decline in both public subsidies and in output prices after the mid 1990s.
Dictionary-Type Data Compression for Gray-Scale Images
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 80199 Artificial Intelligence and Image Processing not elsewhere classified
subject: FOS: Computer and information sciences

description: We explore modifications of the LZ77 type dictionary compression algorithm so that it can compress gray-scale images efficiently. We consider the following modifications to the LZ77 compression: 1. Limiting the positions to start the pattern match in the search window to four neighboring pixels of the first pixel in the lookahead buffer. 2. Using an approximate matching. 3. Adaptively changing the lookahead buffer size. 4. Combination of approximate matching and exact matching using a non-greedy parsing algorithm. Our method is better than the UNIX compress and worst JPEG, and sometimes better than the best JPEG.
Resummation of background-collinear corrections in strong field QED
Creators: name: Edwards, James P.
name: Ilderton, Anton
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Scattering processes in laser backgrounds are degenerate to the emission of unobservable photons collinear with the laser. We identify processes and observables for which such degeneracies factorise and exponentiate, obtaining the leading-order intensity dependence of these inclusive observables at high laser intensity, correct to all orders in the fine-structure constant (all loops, all emissions). The results show an exponential intensity dependence distinct from that predicted by the Narozhny-Ritus conjecture on the high-intensity behaviour of quantum electrodynamics in strong fields.
description: V2: 14 pages, 6 PDF figures, matches published version
The cooling of shock-compressed primordial gas
Creators: name: Johnson, Jarrett L.
name: Bromm, Volker
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We find that at redshifts z > 10, HD line cooling allows strongly-shocked primordial gas to cool to the temperature of the cosmic microwave background (CMB). This temperature is the minimum value attainable via radiative cooling. Provided that the abundance of HD, normalized to the total number density, exceeds a critical level of ~ 10^{-8}, the CMB temperature floor is reached in a time which is short compared to the Hubble time. We estimate the characteristic masses of stars formed out of shocked primordial gas in the wake of the first supernovae, and resulting from the mergers of dark matter haloes during hierarchical structure formation to be ~ 10 M_{solar}. In addition, we show that cooling by HD enables the primordial gas in relic H II regions to cool to temperatures considerably lower than those reached via H_2 cooling alone. We confirm that HD cooling is unimportant in cases where the primordial gas does not go through an ionized phase, as in the formation process of the very first stars in z ~ 20 minihaloes of mass ~ 10^{6} M_{solar}.
description: 10 pages, 10 figures, accepted for publication in MNRAS with minor revisions, new table added
Improving the bounds of the Multiplicity Conjecture: the codimension 3 level case
Creators: name: Zanello, Fabrizio
Publisher: name: arXiv
Year: 2005
Subjects: subject: Commutative Algebra (math.AC)
subject: FOS: Mathematics
subject: 13H15 primary; 13D02, 13D40, 13E10 secondary

description: The Multiplicity Conjecture (MC) of Huneke and Srinivasan provides upper and lower bounds for the multiplicity of a Cohen-Macaulay algebra $A$ in terms of the shifts appearing in the modules of the minimal free resolution (MFR) of $A$. All the examples studied so far have lead to conjecture (see $[HZ]$ and $[MNR2]$) that, moreover, the bounds of the MC are sharp if and only if $A$ has a pure MFR. Therefore, it seems a reasonable - and useful - idea to seek better, if possibly {\it ad hoc}, bounds for particular classes of Cohen-Macaulay algebras. In this work we will only consider the codimension 3 case. In the first part we will stick to the bounds of the MC, and show that they hold for those algebras whose $h$-vector is that of a compressed algebra. In the second part, we will (mainly) focus on the level case: we will construct new conjectural upper and lower bounds for the multiplicity of a codimension 3 level algebra $A$, which can be expressed exclusively in terms of the $h$-vector of $A$, and which are better than (or equal to) those provided by the MC. Also, our bounds can be sharp even when the MFR of $A$ is not pure. Even though proving our bounds still appears too difficult a task in general, we are already able to show them for some interesting classes of codimension 3 level algebras $A$: namely, when $A$ is compressed, or when its $h$-vector $h(A)$ ends with $(...,3,2)$. Also, we will prove our lower bound when $h(A)$ begins with $(1,3,h_2,...)$, where $h_2\leq 4$, and our upper bound when $h(A)$ ends with $(...,h_{c-1},h_c)$, where $h_{c-1}\leq h_c+1$.
description: 22 pages. A few (non-substantial) changes. To appear in J. of Pure and Appl. Algebra
A cross-cultural study of cereal foods' quality perception
Creators: name: Krutulyte, Rasa
name: Costa, Ana I.
name: Grunert, Klaus G.
name: Krutulyte, Rasa
name: Costa, Ana I.
name: Grunert, Klaus G.
Publisher: name: Unknown
Year: 2006
Subjects: subject: Consumer/Household Economics
subject: Food Consumption/Nutrition/Food Safety
subject: Cereal Foods
subject: Consumer Quality Perception
subject: Total Food Quality Model
subject: Cross - cultural Study

description: Cereal foods' production and use show substantial heterogeneity across Europe. For a category central in most EU diets, cereal foods' quality perception is, nevertheless, surprisingly understudied. With this in mind, 357 Danish, Lithuanian and Portuguese citizens were inquired about the importance of several cues and dimensions in their evaluation of the perceived quality of bread, cookies, breakfast cereals, pasta and vodka. Portuguese and Lithuanians consistently gave a significantly higher average importance to all the cues and quality dimensions considered, for all products, than their Danish counterparts. Nevertheless, respondents in all three samples found expected quality dimensions to be much more important than both extrinsic and intrinsic cues across almost all product categories. Dimensions and cues like taste and country - of- origin were the most relevant to Lithuanians, while taste , label information and price were the most important for Danes. The cues and dimensions Portuguese found relevant were fairly different and more category- dependent. Cues like store type for bread, brand for breakfast cereals, pasta and vodka, country - of- origin for vodka , and price for cookies, pasta and vodka were more often assessed by the Portuguese as relevant for decision- making at the point - of- purchase. This highlights the need for further cross - cultural research on food quality perception.
The Stringy Origins of Galileons and their Novel Limit
Creators: name: Easson, Damien
name: Manton, Tucker
name: Parikh, Maulik
name: Svesko, Andrew
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We show generalized Galileons -- a particular subclass of Horndeski gravity -- arise from a consistent Kaluza-Klein reduction of the low-energy effective action of heterotic string theory to first order in $α'$. This suggests Horndeski theories of gravity have a string-theoretic origin. The form of the Galileonic terms is precisely fixed by parameters of the embedding spacetime, so that only a specific subset of Horndeski theories is permitted by string theory. A novel limit of the model is considered by performing a dimensionful rescaling of $α'$.
description: 37 pages, clarifications added, to appear in JCAP
Modelling agricultural policy reforms in the Mediterranean basin - Adjustments of AGRISIM
Creators: name: Kavallari, Aikaterini
name: Borresch, Rene
name: Schmitz, P. Michael
name: Kavallari, Aikaterini
name: Borresch, Rene
name: Schmitz, P. Michael
Publisher: name: Unknown
Year: 2006
Subjects: subject: Agricultural and Food Policy
subject: MPCs
subject: Euro- Mediterranean Association

description: In recent years the Mediterranean countries encounter a number of changes of the agricultural policy that could influence significantly their agricultural sector and thus their overall economy. They are faced with the ongoing trade liberalisation, the Reform of the Common Agricultural Policy (CAP) of the European Union (EU), since the EU is one of the major trade partners of the Mediterranean countries and the establishment of a Free Trade Area between the EU and the Mediterranean Countries after 2010. The latest is/will be accomplished through the Euro- Mediterranean Association Agreements, was decided in the Summit of Barcelona in 1995 and is particularly up- to date after 2005, 10 years after the establishment of the Barcelona Agreement. These changes are expected above all to influence the trade flows between the EU and the Mediterranean Partner Countries (MPC) and therefore, to have impacts on the production, consumption, domestic and border prices and welfare. Aim of the paper is to discuss methodological issues connected with the modelling of policy changes in the Mediterranean basin and to provide more insights on the modification of the model AGRISIM so as to make it a suitable tool to analyse the trade flows in the Mediterranean basin.
Accidents on Rural Interstate and Parkway Roads and their Relation to Pavement Friction
Creators: name: Rizenbergs, Rolands L.
name: Burchett, James L.
name: Deacon, John A.
name: Napier, Cass T.
Publisher: name: Kentucky Transportation Center, University of Kentucky
Year: 1974
Subjects: subject: Transportation Engineering

description: Friction measurements were made with a skid trailer at 70 mph (31 m/s) on 770 miles (1240 km) of rural, four-lane, controlled-access routes on the interstate and parkway systems in Kentucky. Each construction project was treated as a test section. Accident experience, friction measurements, and traffic volumes were obtained for each. Various relationships between wet-weather accidents and skid resistance were analyzed. Averaging methods were used as a means of developing trends and minimizing scatter. A moving average for progressively-ordered sets of five test sections yielded more definite results. The expression of accident occurrence which correlated best with skid and slip resistance was wet-weather accidents per 100 million vehicle miles (161 million vehicle kilometers). Accidents increased greatly as Skid Numbers (70 mph or 31 m/s) decreased from 27. Analysis of Peak Slip Numbers and accident occurrences indicated similar trends.
Better safe than sorry: Non-stomatal mechanisms delay drought stress and hydraulic failure in Scots pine saplings
Creators: name: Nadal-Sala, Daniel
name: Grote, Rüdiger
name: Birami, Benjamin
name: Knüver, Timo
name: Lutzemberger, Martha
name: Rehschuh, Romy
name: Schwarz, Selina
Publisher: name: Karlsruher Institut für Technologie (KIT)
Year: 2021

description: Background/Question/Methods There is no more vital connection than the tight linkage between water and organic carbon, and there is no more paradigmatic example for that than plant photosynthesis. In plants, carbon uptake is done at elevated expenses in terms of water transport from soil to the atmosphere. Under limited water supply, transpiration increases the tension of the within-tree water column. This will eventually lead to emboli formation and loss of hydraulic conductivity, and may result in tree death. The main mechanism by which trees slow down such tension increases is by actively closing their stomata. However, even if stomata are fully closed, some water loss can still occur through cuticular evaporation. Therefore, non-stomatal mechanisms exist that additionally reduce water losses, and hence increase hydraulic safety. Among these, leaf shedding as well as non-stomatal limitations over photosynthesis (NSL, combining increases in mesophyll conductance and biochemical down-regulation on photosynthesis), are well-known but poorly quantified mechanisms that trees may trigger to save water under drought stress. In order to better describe such mechanisms quantitatively, we conducted a severe two-month-long dry-down experiment on potted Scots pine (Pinus sylvestris L.) saplings (n = 6) and under controlled conditions. We measured tree transpiration, photosynthesis and leaf shedding. Based on our observations we trained a state-of-the-art tree hydraulic model and we quantified the impact of the above-mentioned processes on whole-tree percent loss of conductance. Results/Conclusions We found that NSL play a key role in tree drought response by further reducing conductance, which subsequently reduces transpiration and delays dehydration. If sap flow was reduced below a given threshold, saplings responded by shedding leaves. Noteworthy, this threshold was uncorrelated to soil water content. Leaf shedding buffered reductions in xylem water potential and loss of whole-tree conductance in the mid-term. This indicates a hierarchy of active acclimation processes involving a continuous NSL response, and a threshold-based leaf area reduction when P. sylvestris is in danger to lose water to dangerous degrees without any counterpart in form of photosynthetic gain. Combined, both mechanisms reduce whole-plant C uptake, but contribute to tree survival under drought stress.
Agricultural cooperatives and quality-enhancing R&D in the agri-food system
Creators: name: Drivas, Kyriakos
name: Giannakas, Konstantinos
name: Drivas, Kyriakos
name: Giannakas, Konstantinos
Publisher: name: Unknown
Year: 2006
Subjects: subject: Agribusiness
subject: Research and Development/Tech Change/Emerging Technologies
subject: Open Membership Cooperatives
subject: Product Innovation
subject: Mixed Oligopoly
subject: Retained Earnings.

description: This paper develops a game - theoretic model of heterogeneous consumers to analyze the effect of cooperative involvement on quality- enhancing product innovation activity, the pricing of food products, and the welfare of the groups involved in the context of a mixed duopoly where an openmembership consumer co- op competes with an IOF. Analytical results show that the involvement of the member welfare- maximizing co- op in R&D can be quality and welfare enhancing by increasing the arrival rate of product innovations and reducing the prices of food products. The effectiveness of the co- op is shown to depend on the nature of product differentiation and the relative quality of its products, the degree of consumer heterogeneity, and the size of innovation costs .
A general solution for accelerating screw dislocations in arbitrary slip systems with reflection symmetry
Creators: name: Blaschke, Daniel N.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Solutions to the differential equations of linear elasticity in the continuum limit in arbitrary crystal symmetry are known only for steady-state dislocations of arbitrary character, i.e. line defects moving at constant velocity. Troubled by singularities at certain `critical' velocities (typically close to certain sound speeds), these dislocation fields are thought to be too idealized, and divergences are usually attributed to neglecting the finite size of the core and to the restriction to constant velocity. In the isotropic limit, accelerating pure screw and edge dislocations were studied some time ago. A generalization to anisotropic crystals has been attempted for pure screw and edge dislocations only for some special cases. This work aims to fill the gap of deriving a general anisotropic solution for pure screw dislocations applicable to slip systems featuring a reflection symmetry, a prerequisite to studying pure screw dislocations without mixing with edge dislocations. Further generalizations to arbitrary mixed dislocations as well as regularizations of the dislocation core are beyond the scope of this paper and are left for future work.
description: 27 pages, 6 figures; v2 minor clarifications; v3+v4 revised and expanded
Reventlow, Henning Graf: Bibelautorität und Geist der Moderne
Creators: name: Gassmann, Günther
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 31 Nr. 1 (1982): Ökumenische Rundschau, Band 31, Heft 1
Path-Integral Optimization from Hartle-Hawking Wave Function
Creators: name: Boruch, Jan
name: Caputa, Pawel
name: Takayanagi, Tadashi
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a gravity dual description of the path-integral optimization in conformal field theories arXiv:1703.00456, using Hartle-Hawking wave functions in anti-de Sitter spacetimes. We show that the maximization of the Hartle-Hawking wave function is equivalent to the path-integral optimization procedure. Namely, the variation of the wave function leads to a constraint, equivalent to the Neumann boundary condition on a bulk slice, whose classical solutions reproduce metrics from the path-integral optimization in conformal field theories. After taking the boundary limit of the semi-classical Hartle-Hawking wave function, we reproduce the path-integral complexity action in two dimensions as well as its higher and lower dimensional generalizations. We also discuss an emergence of holographic time from conformal field theory path-integrals.
description: 7 pages, Revtex, 1 Figure, 1 Appendix, v2: Typos corrected, published version
Effects of nanoscale spatial inhomogeneity in strongly correlated systems
Creators: name: Silva, M. F.
name: Lima, N. A.
name: Malvezzi, A. L.
name: Capelle, K.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We calculate ground-state energies and density distributions of Hubbard superlattices characterized by periodic modulations of the on-site interaction and the on-site potential. Both density-matrix renormalization group and density-functional methods are employed and compared. We find that small variations in the on-site potential $v_i$ can simulate, cancel, or even overcompensate effects due to much larger variations in the on-site interaction $U_i$. Our findings highlight the importance of nanoscale spatial inhomogeneity in strongly correlated systems, and call for reexamination of model calculations assuming spatial homogeneity.
description: 5 pages, 1 table, 4 figures, to appear in PRB
Tuning transduction from hidden observables to optimize information harvesting
Creators: name: Nicoletti, Giorgio
name: Busiello, Daniel Maria
Publisher: name: arXiv
Year: 2024
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Biological and living organisms sense and process information from their surroundings, typically having access only to a subset of external observables for a limited amount of time. In this work, we uncover how biological systems can exploit these accessible degrees of freedom (DOFs) to transduce information from the inaccessible ones with a limited energy budget. We find that optimal transduction strategies may boost information harvesting over the ideal case in which all DOFs are known, even when only finite-time trajectories are observed, at the price of higher dissipation. We apply our results to red blood cells, inferring the implemented transduction strategy from membrane flickering data and shedding light on the connection between mechanical stress and transduction efficiency. Our framework offers novel insights into the adaptive strategies of biological systems under non-equilibrium conditions.
On relative commutants of subalgebras in group and tracial crossed product von Neumann algebras
Creators: name: Amrutam, Tattwamasi
name: Bassi, Jacopo
Publisher: name: arXiv
Year: 2024
Subjects: subject: Operator Algebras (math.OA)
subject: Functional Analysis (math.FA)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 46L55, 37A55, 47L65

description: Let $Γ$ be a discrete group acting on a compact Hausdorff space $X$. Given $x\in X$, and $μ\in\text{Prob}(X)$, we introduce the notion of contraction of $μ$ towards $x$ with respect to unitary elements of a group von Neumann algebra not necessarily coming from group elements. Using this notion, we study relative commutants of subalgebras in tracial crossed product von Neumann algebras. The results are applied to negatively curved groups and $\text{SL}(d,\mathbb{Z})$, $d \geq 2$.
description: This is the final version. All the suggestions of the referees have been implemented. To appear in the Pacific Journal of Mathematics
String Theory, the Dark Sector and the Hierarchy Problem
Creators: name: Berglund, Per
name: Hübsch, Tristan
name: Minic, Djordje
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We discuss dark energy, dark matter and the hierarchy problem in the context of a general non-commutative formulation of string theory. In this framework dark energy is generated by the dynamical geometry of the dual spacetime while dark matter, on the other hand, comes from the degrees of freedom dual to the visible matter. This formulation of string theory is sensitive both to the IR and UV scales and the Higgs scale is radiatively stable by being a geometric mean of radiatively stable UV and IR scales. We also comment on various phenomenological signatures of this novel approach to dark energy, dark matter and the hierarchy problem. We find that this new view on the hierarchy problem is realized in a toy model based on a non-holomorphic deformation of the stringy cosmic string. Finally, we discuss a proposal for a new non-perturbative formulation of string theory, which sheds light on M theory and F theory, as well as on supersymmetry and holography.
description: 10 pages, typo fixed, reference added
Real-Time Full Signature Corrosion Detection of Underground Casing Pipes
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 40401 Electrical and Electromagnetic Methods in Geophysics
subject: FOS: Earth and related environmental sciences

description: Steel casing pipes used in underground gas storage or in oil fields are subjected to corrosion. Corrosion frequently causes some pitting or wall thinning to the internal or external of casing pipes. More serious corrosion would form holes on the casing pipes and induce serious operational problems. Hence, corrosion monitoring and early detection of field oil pipe is considerably important to the gas and petroleum industry.
We will introduce in this paper a new version of the Direct Current (DC) electromagnetic induction system which is capable of detecting small: isolated corrosion pits and holes on the casing wa1L A sensor system based on the DC electromagnetic induction instrument is coupled to an updated data acquisition system. Unlike the conventional DC induction instrument, this system transmits all the measured leakage (FL) signals and eddy current (EC) signals to the computer logging system (CLS) on surface.
To transmit the information represented by enormous data acquired by the downhole instruments to the CLS on surface. a wavelet data compression technique is incorporated. A VLSI integrated circuit (IC) realizing wavelet transform has been designed so that the real time mode can be achieved during the logging operation. The circuit has been designed using a CMOS n-well 2µm technology and has been fabricated by MOSIS.
Impact of agricultural trade liberalization between the EU and Mediterranean countries: the case of the tomato processing industry
Creators: name: Montigaud, Jean-Claude
name: Coelho, Alfredo
name: Giacomini, Corrado
name: Briz, Julian
name: Montigaud, Jean-Claude
name: Coelho, Alfredo
name: Giacomini, Corrado
name: Briz, Julian
Publisher: name: Unknown
Year: 2006
Subjects: subject: International Relations/Trade
subject: EU
subject: Mediterranean countries
subject: trade liberalization
subject: tomato products
subject: commodity system
subject: case studies (Copador, Louis Martin, Alsat)

description: This study aims to describe and explain the impact of trade liberalization between the EU- 15 and the southern Mediterranean countries, with special emphasis on Southern EU (Portugal, Spain, France, Italy and Greece). The selected activity to be studied is the processing tomato industry. To do that, we use three related approaches (systems, industrial economics and management tools). After describing the tomato processing system, we introduce three case studies: Copador (member of CIO) located in Parma, Louis Martin SA nearby Avignon and Alsat SL located in Don Benito (Extremadura). Some conclusions : the EU processing tomato industry will continue and probably expand its activities on the Mediterranean borders; the competition between Italy and Spain will increase; the southern part of France risks losing its first - level processing activities; specialization of work within the European space will intensify, with the southern part specializing in raw materials and the northern part in high value added products; Greek and Portuguese activities will carry on. Three main reasons can be advanced: the raw materials have to meet some very rigorous standards; some activities (manufacturing of tomato paste) are highly mechanized and, second and third level finished products which are evolving very quickly (packaging, recipes and process techniques) require good logistics and flexible services.
On the origin of the type-III radiation observed near the Sun
Creators: name: Mozer, Forrest
name: Agapitov, Oleksiy
name: Bale, Stuart
name: Goetz, Keith
name: Krasnoselskikh, Vladimir
name: Pulupa, Marc
name: Sauer, Konrad
name: Voshchepynets, Andrii
Publisher: name: arXiv
Year: 2024
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: $\textit{AIMS.}$ To investigate processes associated with generation of type-III radiation.
 $\textit{METHODS.}$ Measure the amplitudes and phase velocities of Parker Solar Probe observed electric fields, magnetic fields, and plasma density fluctuations.
 $\textit{RESULTS.}$ (1) There are slow electrostatic waves near the Langmuir frequency and at as many as six harmonics, the number of which increases with the amplitude of the Langmuir wave. Their electrostatic nature is shown by measurement of the plasma density fluctuations. From these density fluctuations and the electric field magnitude, the k-value of the Langmuir wave is estimated to be 0.14 and $k λ_d$ = 0.4. Even with a large uncertainty in this quantity (more than a factor of two) the phase velocity of the Langmuir wave was <10,000 km/sec. (2) There is an electromagnetic wave near the Langmuir frequency having a phase velocity <50,000 km/sec. (3) Whether there are electromagnetic waves at the harmonics of the Langmuir frequency cannot be determined because, if they existed, their magnetic field components would be below the noise level of the measurement. (4) The rapid (less than one msec) amplitude variations typical of the Langmuir wave and its harmonics are artifacts resulting from addition of two waves, one of which has small frequency variations that arise from traveling through density irregularities. None of these results are expected in or consistent with the conventional model of the three-wave interaction of two counter-streaming Langmuir waves that coalesce to produce the type-III wave. They are consistent with a new model in which electrostatic antenna waves are produced at the harmonics by radiation of the Langmuir wave, after which at least the first harmonic wave evolved through density irregularities such that its wave number decreased and it became the type-III radiation.
Quality related communication approaches for organic food
Creators: name: Bodini, Antonella
name: Richter, T.
name: Felder, R.
name: Bodini, Antonella
name: Richter, T.
name: Felder, R.
Publisher: name: Unknown
Year: 2006
Subjects: subject: Marketing
subject: FOS: Economics and business

description: As food quality becomes more complex, consumer s are tending to reduce their involvement in the food purchase decision- making process. Consequently, prices are becoming more significant as they represent an easy choice criterion when consumer s have less information about the differences between the product and process quality inherent in food items (including environmental or social issues). The organic food sector provides high, complex food quality profiles and has therefore been seriously affected by this development. Consequently some SMEs in the food business sector are starting to emphasize certain quality factors, such as sustainable production and processing, as a means of communicating their added value to consumer s. Based on published scientific and unpublished literature, this paper provides an overview of the main instrument s and media of communication on food quality, illustrated by case studies. It also present s the results of a test by means of an information display matrix, conducted in order to analyse the consumer information and quality assessment behaviour involved in apple purchase in Switzerland. Keywords food quality, food indicators, means of communication, food miles, social standards, consumer behaviour.
FARM FAMILY TRANSITION TO OFF-FARM EMPLOYMENT: A COMPARISON OF HOUSEHOLDS IN THREE STAGES OF TRANSITION
Creators: name: Cummings, Laurie Angela
name: Cummings, Laurie Angela
Publisher: name: Unknown
Year: 1992
Subjects: Farm Management
Labor and Human Capital

description: This paper uses data from a survey of 710 Michigan farm families who actively sought assistance in transitioning from farm to off-farm employment during the period of 1986 to 1988. Respondents were divided into three transition groups depending on the degree to which they depend off-farm income. The three groups represent farm households that have completely transitioned out of agriculture, largely transitioned out, and those who are still primarily dependent on agriculture. Results reveal that 33 percent have made a complete transition, 48 percent are part-time farming, and 19 percent are full-time farming. Those practicing part-time farming were found to have higher incomes than those who completely quit farming and those full-time farming. Education, application of skills to off-farm employment, and the gender of household members seeking employment assistance were found to be significant factors in the ability to transition out of farming. Allocation of family labor was also found to be important--those who have made the greatest economic recovery most often had two family members working off-farm in 1990.
A critical view on the deeply bound K^- pp system
Creators: name: Magas, V. K.
name: Oset, E.
name: Ramos, A.
name: Toki, H.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We briefly review the situation around the claimed deeply bound K^- states in different recent experiments and concentrate particularly on the state K^- pp advocated by the FINUDA collaboration in nuclear K^- absorption. We perform a theoretical simulation of the process and show that the peak in the Lambda p spectrum that was interpreted as a deep K^- pp bound state corresponds mostly to the process K^- p p --> Lambda p followed by final state interactions of the produced particles with the daughter nucleus.
description: 11 pages, 14 figures
Image Compression with Modified LZ77 Coding
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 80106 Image Processing
subject: FOS: Computer and information sciences
subject: Artificial Intelligence and Image Processing

description: We present in this paper a new coding method for lossless gray-scale image compression. Our method is based on modifications of LZ77-based compression and estimation of prediction errors of pixels. Our method gives compression comparable to JPEG lossless mode and its speed is about twice that of JPEG lossless mode with arithmetic coding.
Density profile evolution during prestellar core collapse: Collapse starts at the large scale
Creators: name: Gómez, Gilberto C.
name: Vázquez-Semadeni, Enrique
name: Palau, Aina
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the gravitationally-dominated, accretion-driven evolution of a prestellar core. In our model, as the core's density increases, it remains immersed in a constant-density environment and so it accretes from this environment, increasing its mass and reducing its Jeans length. Assuming a power-law density profile $ρ\propto r^{-p}$, we compute the rate of change of the slope $p$, and show that the value $p=2$ is stationary, and furthermore, an attractor. The radial profile of the Jeans length scales as $r^{p/2}$, implying that, for $p<2$, there is a radius below which the region is smaller than its Jeans length, thus appearing gravitationally stable and in need of pressure confinement, while, in reality, it is part of a larger-scale collapse and is undergoing compression by the infalling material. In this region, the infall speed decreases towards the center, eventually becoming subsonic, thus appearing "coherent", without the need for turbulence dissipation. We present a compilation of observational determinations of density profiles in dense cores and show that the distribution of their slopes peaks at $p \sim 1.7$--1.9, supporting the notion that the profile steepens over time. Finally, we discuss the case of magnetic support in a core in which the field scales as $B \propto ρ^β$. For the expected value of $β= 2/3$, this implies that the mass to magnetic flux ratio also decreases towards the central parts of the cores, making them appear magnetically supported, while in reality they may be part of larger collapsing supercritical region. We conclude that local signatures of either thermal or magnetic support are not conclusive evidence of stability, that the gravitational instability of a region must be established at the large scales, and that the prestellar stage of collapse is dynamic rather than quasistatic.
description: Accepted for publication in MNRAS
Decorrelation of a leader by the increasing number of followers
Creators: name: Majumdar, Satya N.
name: Schehr, Gregory
Publisher: name: arXiv
Year: 2024
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We compute the connected two-time correlator of the maximum $M_N(t)$ of $N$ independent Gaussian stochastic processes (GSP) characterised by a common correlation coefficient $ρ$ that depends on the two times $t_1$ and $t_2$. We show analytically that this correlator, for fixed times $t_1$ and $t_2$, decays for large $N$ as a power law $N^{-γ}$ (with logarithmic corrections) with a decorrelation exponent $γ= (1-ρ)/(1+ ρ)$ that depends only on $ρ$, but otherwise is universal for any GSP. We study several examples of physical processes including the fractional Brownian motion (fBm) with Hurst exponent $H$ and the Ornstein-Uhlenbeck (OU) process. For the fBm, $ρ$ is only a function of $τ= \sqrt{t_1/t_2}$ and we find an interesting ``freezing'' transition at a critical value $τ= τ_c=(3-\sqrt{5})/2$. For $τ< τ_c$, there is an optimal $H^*(τ) > 0$ that maximises the exponent $γ$ and this maximal value freezes to $γ= 1/3$ for $τ>τ_c$. For the OU process, we show that $γ= {\rm tanh}(μ\,|t_1-t_2|/2)$ where $μ$ is the stiffness of the harmonic trap. Numerical simulations confirm our analytical predictions.
description: Main text: 6 pages, 3 figures. Supplementary material: 10 pages
HERD STRUCTURE, PRODUCTION TRAITS, CATTLE TRANSACTIONS AND AN ECONOMIC ANALYSIS OF ALTERNATIVE PRODUCTION SYSTEMS OF ZEBU CATTLE IN N. TANZANIA
Creators: name: Ngategize, Peter K.
name: Ngategize, Peter K.
Publisher: name: Unknown
Year: 1982
Subjects: Livestock Production/Industries

description: Livestock production in developing countries has begun getting much attention from governments, donor agents and researchers. In many countries cash crops constituted the major source of foreign exchange earnings and thus got much more attention than livestock production. However, the 1970's were generally a period of falling prices for most of the major cash crops (coffee, cocoa, cotton, sisal, etc.). The critical need for turning to other foreign exchange earning commodities, the need to reduce the importation of manufactured foodstuffs and the growing demand for animal proteins plus the pressure to improve the living conditions of the usually less privileged pastoral and agripastoral communities requires full understanding of the production potentials and constraints in their respective production systems. The study set out to bring together the current literature on herd structure, production traits and cattle transactions of zebu herds in tropical Africa. Specifically the study examines the herd characteristics and productivity of W'Arusha zebu herds in N. Tanzania. The first chapter includes the problem statement, objectives and limitations of the study. In the second chapter, an introduction to Tanzania is made covering geographic, economic and social characteristics. The geographical, historical, and production conditions of the W'Arusha and the data collection methodology are presented. The most important parts of the study are contained in chapter 3, 4, and 5. In chapter 3, literature, covering a wide range of production systems and management conditions is reviewed. Chapter 4 reports the results of the study from the W'Arusha sample herd. Chapter 5 presents the results of the regression analysis and herd growth simulations. Chapter 6 presents the conclusion from the study based on the literature and the findings from the sample herd. Some recommendations for further research, especially, covering the economics of production in livestock system are presented.
Diffusion entropy analysis on the scaling behavior of financial markets
Creators: name: Cai, Shi-Min
name: Zhou, Pei-Ling
name: Yang, Hui-Jie
name: Yang, Chun-Xia
name: Wang, Bing-Hong
name: Zhou, Tao
Publisher: name: arXiv
Year: 2005
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: In this paper the diffusion entropy technique is applied to investigate the scaling behavior of financial markets. The scaling behaviors of four representative stock markets, Dow Jones Industrial Average, Standard&Poor 500, Heng Seng Index, and Shang Hai Stock Synthetic Index, are almost the same; with the scale-invariance exponents all in the interval $[0.92, 0.95]$. These results provide a strong evidence of the existence of long-rang correlation in financial time series, thus several variance-based methods are restricted for detecting the scale-invariance properties of financial markets. In addition, a parsimonious percolation model for stock markets is proposed, of which the scaling behavior agrees with the real-life markets well.
description: 5 pages, 3 figures
Holographic striped superconductor
Creators: name: Ling, Yi
name: Wu, Meng-He
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We construct a holographic model describing the striped superconductor (SSC), which is characterized by the presence of pair density waves (PDW). We explicitly demonstrate that the SSC phase is implemented as the intertwined phase of charge density waves (CDW) order and uniform superconducting (SC) order. Theinterplay of PDW order, CDW order as well as the uniform SC order in SSC phase is studied. It is found that the PDW order is prominent when both CDW order and uniform SC order are balanced. The critical temperature of CDW becomes higher in the presence of the uniform SC order, but its charge density amplitude is suppressed. On the other hand, the SC order is not sensitive to the presence of CDW order. We also demonstrate that among all the possible solutions, the black hole in SSC phase has the lowest free energy and thus is thermodynamically favored.
description: 25 pages, 18 figures
Accretion properties of X-ray AGN: Evidence for radiation-regulated obscuration with redshift-dependent host galaxy contribution
Creators: name: Laloux, Brivael
name: Georgakakis, Antonis
name: Alexander, David M.
name: Buchner, Johannes
name: Andonie, Carolina
name: Acharya, Nischal
name: Aird, James
name: Alonso-Tetilla, Alba V.
name: Bongiorno, Angela
name: Hickox, Ryan C.
name: Lapi, Andrea
name: Musiimenta, Blessing
name: Almeida, Cristina Ramos
name: Villforth, Carolin
name: Shankar, Francesco
Publisher: name: arXiv
Year: 2024
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We adopt a Bayesian X-ray spectral approach to investigate the accretion properties of unobscured ($20<\log(N_{\rm H}/{\rm cm}^{-2}<22$) and obscured ($22< \log(N_{\rm H}/{\rm cm}^{-2}<24$) active galactic nuclei (AGN) to shed light on the orientation vs evolution scenarios for the origin of the obscuring material. For a sample of 3882 X-ray-selected AGN from the {\it Chandra} COSMOS Legacy, AEGIS and CDFS extragalactic surveys, we constrain their stellar masses, $M_\star$, intrinsic X-ray luminosities, $L_{\rm X}$, obscuring column densities, $N_{\rm H}$, and specific accretion rates $λ\propto L_{\rm X}/M_\star$. By combining these observables within a Bayesian non-parametric approach, we infer, for the first time, the specific accretion rate distribution (SARD) of obscured and unobscured AGN to $z\approx3$, i.e. the probability of a galaxy with mass $M_\star$ at redshift $z$ hosting an AGN with column density $N_{\rm H}$ and specific accretion rate $λ$. Our findings indicate that (1) both obscured and unobscured SARDs share similar shapes, shifting towards higher accretion rates with redshift, (2) unobscured SARDs exhibit a systematic offset towards higher $λ$ compared to obscured SARD for all redshift intervals, (3) the obscured AGN fraction declines sharply at $\logλ_{\rm break} \sim-2$ for $z <0.5$, but shifts to higher $λ$ values with increasing redshift, (4) the incidence of AGN within the theoretically unstable blow-out region of the $λ-N_{\rm H}$ plane increases with redshift. These observations provide compelling evidence for AGN "downsizing" and radiation-regulated nuclear-scale obscuration with an increasing host galaxy contribution towards higher redshifts.
description: Published at MNRAS
FRET Tau
Creators: name: García-Escudero, Vega
Publisher: name: figshare
Year: 2025
Subjects: classificationCode: 310104
subject: Cell neurochemistry
classificationCode: 320903
subject: Central nervous system

description: Tau aggregation assay using HEK293T Tau RD P301S FRET Biosensor cells (CRL-3275, ATTC) that were transfected with Alzheimer’s-derived Tau seeds and Tau-expressing vectors. Alternatively, cells were treated with different Tau fractions. FRET signal was analyzed using confocal microscopy and Fiji software.
Low-Complexity Joint CFO and Channel Estimation for RIS-aided OFDM Systems
Creators: name: Jeong, Sumin
name: Farhang, Arman
name: Perović, Nemanja Stefan
name: Flanagan, Mark
Publisher: name: arXiv
Year: 2021
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Accurate channel estimation is essential for achieving the performance gains offered by reconfigurable intelligent surface (RIS)-aided wireless communications. A variety of channel estimation methods have been proposed for such systems; however, none of the existing methods takes into account the effect of synchronization errors such as carrier frequency offset (CFO). In general, CFO can significantly degrade channel estimation performance of orthogonal frequency division multiplexing (OFDM) systems. Motivated by this, we investigate the effect of CFO on channel estimation for RIS-aided OFDM systems. Furthermore, we propose a joint CFO and channel impulse response (CIR) estimation method for these systems. Simulation results demonstrate the effectiveness of our proposed method, and also demonstrate that the use of time-domain rather than frequency-domain estimation in this context results in an improvement in the mean-squared error (MSE) performance of channel estimation as well as a significantly lower overall computational complexity.
description: 5 pages, 5 figures, this manuscript has been submitted to IEEE WCL and accepted (Digital Object Identifier:10.1109/LWC.2021.3124049)