scholarly journals First order conditions for generalized variational problems over time scales

2011 ◽  
Vol 62 (9) ◽  
pp. 3490-3503 ◽  
Author(s):  
Roman Šimon Hilscher ◽  
Vera Zeidan
Keyword(s):  
Time Scales ◽  
Variational Problems ◽  
Order Conditions ◽  
First Order ◽  
Over Time

scholarly journals Variability of L Dwarfs in the Near Infrared

2003 ◽  
Vol 211 ◽  
pp. 455-456 ◽  
Author(s):  
José A. Caballero ◽  
Víctor J. S. Béjar ◽  
Rafael Rebolo
Keyword(s):  
Time Scales ◽  
Near Infrared ◽  
Brown Dwarfs ◽  
L Dwarfs ◽  
Atmospheric Changes ◽  
Changes Over Time ◽  
Over Time

We have obtained series of images in the near infrared J and Ks bands for seven L-type dwarfs with a duration of 3 to 6 hours. We present results on: 1) the amplitude of variability associated with atmospheric changes over time scales from minutes to several hours; 2) the search for cool companions in wide orbits; 3) the search for transits of brown dwarfs and planetary companions in very close orbits.

scholarly journals Priestley duality for MV-algebras and beyond

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wesley Fussner ◽  
Mai Gehrke ◽  
Samuel J. van Gool ◽  
Vincenzo Marra
Keyword(s):  
Large Class ◽  
Order Conditions ◽  
Enriched Environment ◽  
Priestley Duality ◽  
Distributive Lattices ◽  
First Order ◽  
Dual Spaces ◽  
Binary Operations ◽  
New Perspective ◽  
Mv Algebras

Abstract We provide a new perspective on extended Priestley duality for a large class of distributive lattices equipped with binary double quasioperators. Under this approach, non-lattice binary operations are each presented as a pair of partial binary operations on dual spaces. In this enriched environment, equational conditions on the algebraic side of the duality may more often be rendered as first-order conditions on dual spaces. In particular, we specialize our general results to the variety of MV-algebras, obtaining a duality for these in which the equations axiomatizing MV-algebras are dualized as first-order conditions.

scholarly journals Constraints in models of production and cost via slack-based measures

2021 ◽  
Author(s):  
Caroline Khan ◽  
Mike G. Tsionas
Keyword(s):  
Power Generation ◽  
Stochastic Frontier ◽  
Inequality Constraints ◽  
Order Conditions ◽  
Flexible Functional Forms ◽  
Cost Share ◽  
First Order ◽  
Stochastic Frontier Models ◽  
Endogenous Variables ◽  
Functional Forms

AbstractIn this paper, we propose the use of stochastic frontier models to impose theoretical regularity constraints (like monotonicity and concavity) on flexible functional forms. These constraints take the form of inequalities involving the data and the parameters of the model. We address a major concern when statistically endogenous variables are present in these inequalities. We present results with and without endogeneity in the inequality constraints. In the system case (e.g., cost-share equations) or more generally, in production function-first-order conditions case, we detect an econometric problem which we solve successfully. We provide an empirical application to US electric power generation plants during 1986–1997, previously used by several authors.

Information Used in Detecting Upcoming Collision

Perception ◽  
10.1068/p3433 ◽  
2003 ◽  
Vol 32 (5) ◽  
pp. 525-544 ◽  
Author(s):  
Reinoud J Bootsma ◽  
Cathy M Craig
Keyword(s):  
Significant Role ◽  
First Order ◽  
Near Future ◽  
Over Time

In four experiments we examined the nature of the information used in judging whether events would or would not give rise to a collision in the near future. Observers were tested in situations depicting approaches between two objects (lateral approaches) and approaches between an object and the point of observation (head-on approaches), with objects moving according to constant deceleration or sinusoidal deceleration patterns. Judgments were found to be based, to a large extent, on the (in)sufficiency of current deceleration to avoid upcoming collision, as specified optically by tau-dot (τ̇). However, the information specified by tau (τ), that is the current (first-order) time remaining until contact, was also found to play a significant role. We deduce that judgment of upcoming collision is based on the detection of τ and its evolution over time, suggesting that observers are sensitive to Δτ rather than to τ̇ itself.

International Real Estate Review

2016 ◽  
Vol 19 (3) ◽  
pp. 265-296
Author(s):  
Richard D. Evans ◽  
◽  
Glenn R. Mueller ◽  
Keyword(s):  
Markov Chain ◽  
Real Estate ◽  
Cash Flow ◽  
Discounted Cash Flow ◽  
First Order ◽  
Order Markov Chain ◽  
Office Markets ◽  
Speed Up ◽  
Staying Time ◽  
Over Time

Metro market real estate cycles for office, industrial, retail, apartment, and hotel properties may be specified as first order Markov chains, which allow analysts to use a well-developed application, ¡§staying time¡¨. Anticipations for time spent at each cycle point are consistent with the perception of analysts that these cycle changes speed up, slow down, and pause over time. We find that these five different property types in U.S. markets appear to have different first order Markov chain specifications, with different staying time characteristics. Each of the five property types have their longest mean staying time at the troughs of recessions. Moreover, industrial and office markets have much longer mean staying times in very poor trough conditions. Most of the shortest mean staying times are in hyper supply and recession phases, with the range across property types being narrow in these cycle points. Analysts and investors should be able to use this research to better estimate future occupancy and rent estimates in their discounted cash flow (DCF) models.

scholarly journals Growth analysis of sweet pepper cultivated in coconut fiber in a greenhouse

2011 ◽  
Vol 29 (3) ◽  
pp. 316-323 ◽  
Author(s):  
Hamilton César de O Charlo ◽  
Sueyde F de Oliveira ◽  
Renata Castoldi ◽  
Pablo F Vargas ◽  
Leila T Braz ◽  
...  
Keyword(s):  
Growth Analysis ◽  
Dry Mass ◽  
Sweet Pepper ◽  
Absolute Rate ◽  
Coconut Fiber ◽  
First Order ◽  
Growth Production ◽  
Four Blocks ◽  
Over Time

Knowledge about the growth of crops allows the planning of rational cultivation methods which contribute to achieve greater potential of plant species, besides supplying information for the construction of descriptive mathematical models of growth. The growth curve of sweet pepper (Eppo hybrid), cultivated in coconut fiber in a greenhouse with fertirrigation, was determined. The experiment consisted initially of 160 plants divided into four blocks. Two plants were analyzed per block every 21 days after transplanting, ending at 189 days after transplant. The cultivation was carried out in plastics pots of 13 L containing coconut fiber, which were arranged in double rows, spaced 0.5 x 0.8 m between simple rows and 1.1 m between double rows. In each harvest the plant growth, production and quality of mature fruits were evaluated. The dry mass of the shoot increased with time, following the experimental model exponential of first order, reaching a maximum of 451.5 g/plant, 189 days after transplanting (DAT). The production of dry mass of leaves, stem, root and fruit also increased over time reaching maximum values of 68.7, 65.8, 11.5 and 302.9 g/plant, respectively, at 189 DAT. The same occurred with the leaf area per plant, plant height and the absolute rate of growth, whose maximum values were 6.183,5 cm², 136.9 cm and 4.4 g/plant/day, respectively. The growth of the plant was continuous throughout the cycle, and the highest amount of dry mass was accumulated in fruits, reaching a marketable production of 97.3 t ha-1. All fruits were classified as Extra.

The Sedimentary Cycle on Early Mars

2019 ◽  
Vol 47 (1) ◽  
pp. 91-118 ◽  
Author(s):  
Scott M. McLennan ◽  
John P. Grotzinger ◽  
Joel A. Hurowitz ◽  
Nicholas J. Tosca
Keyword(s):  
Plate Tectonics ◽  
Sedimentary Rock ◽  
First Order ◽  
Sedimentary Environments ◽  
Source To Sink ◽  
Rock Record ◽  
Mineral Assemblages ◽  
Sedimentary Cycle ◽  
Early Mars ◽  
Over Time

Two decades of intensive research have demonstrated that early Mars ([Formula: see text]2 Gyr) had an active sedimentary cycle, including well-preserved stratigraphic records, understandable within a source-to-sink framework with remarkable fidelity. This early cycle exhibits first-order similarities to (e.g., facies relationships, groundwater diagenesis, recycling) and first-order differences from (e.g., greater aeolian versus subaqueous processes, basaltic versus granitic provenance, absence of plate tectonics) Earth's record. Mars’ sedimentary record preserves evidence for progressive desiccation and oxidation of the surface over time, but simple models for the nature and evolution of paleoenvironments (e.g., acid Mars, early warm and wet versus late cold and dry) have given way to the view that, similar to Earth, different climate regimes on Mars coexisted on regional scales and evolved on variable timescales, and redox chemistry played a pivotal role. A major accomplishment of Mars exploration has been to demonstrate that surface and subsurface sedimentary environments were both habitable and capable of preserving any biological record. ▪ Mars has an ancient sedimentary rock record with many similarities to but also many differences from Earth's sedimentary rock record. ▪ Mars’ ancient sedimentary cycle shows a general evolution toward more desiccated and oxidized surficial conditions. ▪ Climatic regimes of early Mars were relatively clement but with regional variations leading to different sedimentary mineral assemblages. ▪ Surface and subsurface sedimentary environments on early Mars were habitable and capable of preserving any biological record that may have existed.

scholarly journals Cross-Correlations in Meat Prices in Brazil: A Non-Linear Approach Using Different Time Scales

Economies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 133
Author(s):  
Derick Quintino ◽  
José Telo da Gama ◽  
Paulo Ferreira
Keyword(s):  
Time Scales ◽  
Cross Correlation ◽  
Positive Association ◽  
Recent Period ◽  
Linear Approach ◽  
Long Run ◽  
Short Run ◽  
Cross Correlations ◽  
Over Time ◽  
Different Time Scales

Brazil is one of the world’s largest producers and exporters of cattle, chicken and swine. Therefore, co-movements of Brazilian meat prices are important for both domestic and foreign stakeholders. We propose to analyse the cross-correlation between meat prices in Brazil, namely, cattle, swine and chicken, including also in the analysis information from some commodities, namely maize, soya beans, oil, and the Brazilian exchange rate. Our sample covers the recent period which coincided with extensive macroeconomic and institutional changes in Brazil, from 2011 to 2020, and is divided in two periods: (i) presidential pre-impeachment (P1), occurring in August 2016, and; (ii) post-impeachment (P2). Our results indicate that in P1, only the prices of swine and chicken showed a positive and strong correlation over time, and that cattle showed some positive correlation with chicken only in the short run. In P2, there was also a positive and consistent correlation between swine and chicken, and only a positive association with swine and cattle in the long run. For more spaced time scales (days), the changes in the degree of correlation were significant only in the long run for swine and cattle.

Sign in / Sign up

Export Citation Format

Share Document