scholarly journals Functional Forms and Farm-Level Demand for Pecans by Variety

1991 ◽  
Vol 23 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Albert A. Okunade ◽  
Mark J. Cochran
Keyword(s):  
Functional Form ◽  
Turning Points ◽  
Past Research ◽  
Nominal Data ◽  
Farm Level ◽  
Specific Analysis ◽  
Recent Developments ◽  
Functional Forms ◽  
Price Flexibility ◽  
The U.S

AbstractRecent developments in the U.S. pecan industry appear to limit the utility of past research. The importance of pecan variety has emerged as an issue which could alter past results. The linear and double-log models previously fitted to all-pecans (averaged) data may be too restrictive and hence, are less useful for variety-specific analysis. Past research also analyzed price turning points using nominal data. This study investigated functional form and data-averaging problems by fitting separate flexible Box-Cox price-dependent models for all-pecans and each variety of pecans (1970/71-1988/89 deflated data). Results indicate: other nuts substitute for different pecan varieties, estimated all-pecans price flexibility is biased and clouds variety-specific flexibilities, and restrictive functional forms are inappropriate.

scholarly journals Nonrobustness of Dynamic Dual Models of the U.S. Dairy Industry

1989 ◽  
Vol 18 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Wayne H. Howard ◽  
C. Richard Shumway
Keyword(s):  
Technological Change ◽  
Functional Form ◽  
Dairy Industry ◽  
Dual Model ◽  
Competitive Firm ◽  
Functional Forms ◽  
Quality Indexes ◽  
Dual Models ◽  
The U.S

The robustness of dynamic dual model results across functional forms is examined for the U.S. dairy industry. Modified generalized Leontief (GL) and normalized quadratic (NQ) functional forms are compared by examining their consistency with properties of the competitive firm, estimated rates of adjustment for cows and labor, tests of technological change, and elasticities. Homogeneity and symmetry are maintained in both models. Convexity is not rejected by the GL and is not seriously violated by the NQ. Absence of technological change is rejected by both models, but quality indexes on labor and cows fully embody technological change occurring within labor and cows in the NQ but not in the GL. Policy-relevant elasticities differ greatly between the functional forms. Dynamic dual models are found to be non-robust in important ways to choice of functional form.

Guns on Campus: Surveying a rugged post-Heller/ McDonald landscape

2013 ◽  
Vol 45 (1-2) ◽  
pp. 77-108 ◽  
Author(s):  
Leif Magne Lervik
Keyword(s):  
Local Governments ◽  
Public Colleges ◽  
Concealed Weapons ◽  
Second Amendment ◽  
Academic History ◽  
Recent Developments ◽  
State And Local ◽  
Public Colleges And Universities ◽  
The Right ◽  
The U.S

In June 2008, the U.S. Supreme Court ruled that the Second Amendment to the U.S. Constitution guarantees an individual the right to keep and bear arms. Two years later, this decision was also made applicable to state and local governments. Today, seven U.S. states have provisions allowing the carrying of concealed weapons on their public senior high school campuses. This article, introduced by a brief comment on the Second Amendment’s legal and academic history, traces several recent developments of legal change. It discusses relevant arguments and attitudes towards guns on campus, and explores issues of future concern for public colleges and universities within the realm of firearms and campus safety.

Recent Developments and Future Changes to Internet Privacy Rules in the EU, the UK and the U.S.

2017 ◽  
Vol 18 (3) ◽  
Author(s):  
David Bender ◽  
Joseph Jones ◽  
Mark Young ◽  
Hendrike Wulfert-Markert
Keyword(s):  
Internet Privacy ◽  
Recent Developments ◽  
The Uk ◽  
The U.S ◽  
The Eu

Forecasting viral disease outbreaks at the farm-level for commercial sow farms in the U.S

2021 ◽  
pp. 105449
Author(s):  
Igor Adolfo Dexheimer Paploski ◽  
Rahul Kumar Bhojwani ◽  
Juan Manuel Sanhueza ◽  
Cesar Agustín Corzo ◽  
Kimberly VanderWaal
Keyword(s):  
Disease Outbreaks ◽  
Viral Disease ◽  
Farm Level ◽  
The U.S

Temporally-ordered CDW creep in pure and doped NbSe3

2002 ◽  
Vol 12 (9) ◽  
pp. 315-315
Author(s):  
K. Cicak ◽  
K. O'Neill ◽  
R. E. Thorne
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Driving Force ◽  
Functional Form ◽  
Collective Motion ◽  
Density Wave ◽  
Velocity Versus ◽  
Initial Work ◽  
Functional Forms ◽  
Creep Velocity

Below T=40 K, charge-density wave (CDW) transport in NbSe3 is characterized by two well-defined driving force thresholds ET and ET*. Between these thresholds the CDW moves extremely slowly with creep-like temperature and driving force dependencies. At the same time, the CDW exhibits coherent oscillations with a frequency proportional to the CDW current and having very narrow spectral widths, suggesting that the collective motion is temporally ordered. We have extended our initial work to doped crystals containing isoelectronic (Ta) and nonisoelectronic (Ti) impurities, and to crystals of different thicknesses. These experiments show that the qualitative features are extremely robust, and that the functional form of the creep velocity versus driving force and temperature is consistent across all samples for currents ranging over five orders of magnitude. The temperature dependence is consistent with processes having an energy comparable to the CDW gap, but the field and impurity dependencies are inconsistent with all predicted functional forms for creep in CDWs and related systems, and with our earlier picture of amplitude collapse at each impurity. We compare our results to measurements of creep-like behavior in other CDW and SDW systems, and discuss possible mechanisms.

scholarly journals A unifying theory to describe transmembrane transport derived from thermodynamic principles

2015 ◽  
Author(s):  
Marco A Herrera-Valdez
Keyword(s):  
Transmembrane Potential ◽  
Functional Form ◽  
Molecular Transport ◽  
Planck Equation ◽  
Transmembrane Transport ◽  
Membrane Excitability ◽  
Nonlinear Functions ◽  
Functional Forms ◽  
Membrane Spanning ◽  
Transmembrane Currents

Herrera-Valdez. A unifying theory of physiological transmembrane transport Cellular homeostasis involves transmembrane molecular transport that is, in turn, mediated by proteins that enable molecular transport along, or against the (electro) chemical gradient of the molecules being transported. Transmembrane transport has been modelled in many studies using many functional forms that were not always derived from the same assumptions. A generic formulation that describes transmembrane fluxes regardless of whether they are mediated by carrier proteins or by open channels is presented here. The functional form of the flux was obtained from basic thermodynamic principles. Further, taking a slightly different approach, the same generic formulation mentioned above can also be obtained from the Nernst-Planck equation for the case of channel- mediated electrodiffusion. The generic formulation can be regarded as the product of an amplitude term and a driving force term, both nonlinear functions of the transmembrane concentrations of the molecules and possibly the transmembrane potential. The former captures the characteristics of the membrane-spanning protein mediating the transport and the latter is a non-linear function of the transmembrane concentrations of the ions. The generic formulation explicitly shows that the basal rate at which ions cross the membrane is the main difference between currents mediated by pumps and channels. Electrogenic transmembrane fluxes can be converted to currents to construct models of membrane excitability in which all the transmembrane currents have the same functional form. The applicability of the generic derivations presented here is illustrated with models of excitability for neurones and pacemaker cardiocytes.

Simulation of the estimation of ageing bias inside an integrated assessment of canary rockfish using age estimates from a bomb radiocarbon study

2007 ◽  
Vol 58 (10) ◽  
pp. 905 ◽  
Author(s):  
Ian J. Stewart ◽  
Kevin R. Piner
Keyword(s):  
Functional Form ◽  
Stock Assessment ◽  
Small Sample Size ◽  
Small Sample ◽  
Assessment Model ◽  
Bomb Radiocarbon ◽  
Interval Width ◽  
Functional Forms ◽  
Age Model ◽  
Spawning Biomass

The stock of canary rockfish off the west coast of the continental US is currently assessed using an integrated statistical catch-at-age model. The functional form of an ageing bias detected in production ageing (large numbers of ages read for use in stock assessment) from a bomb radiocarbon study with small sample size (n = 16) was estimated externally and used to adjust the age data in the most recent stock assessment. Using simulation methods, the present study evaluated whether integrating the estimation of the ageing bias inside the assessment model would (1) influence the uncertainty in assessment results and (2) improve our ability to differentiate between competing functional forms (linear, linear with intercept and jointed) for specifying the ageing bias. Internal estimation of the ageing bias relationship increased the approximate 95% confidence interval width about the spawning biomass estimate by 1–10% depending on the functional form assumed. The assessment model was not able to reliably distinguish between all competing functional forms of the ageing bias tested, even with increased radiocarbon sample sizes. However, significant under-ageing at the youngest ages was found to be inconsistent with other sources of data in the assessment model. The question of ageing bias form remains important because it had moderate effects on estimates of spawning biomass and assessment model uncertainty.

scholarly journals Energy-Related Input Demand by Crop Producers

1983 ◽  
Vol 15 (2) ◽  
pp. 63-69 ◽  
Author(s):  
James B. Kliebenstein ◽  
Francis P. McCamley
Keyword(s):  
Total Energy ◽  
Energy Use ◽  
Fiber Production ◽  
Senate Committee ◽  
Farm Level ◽  
Threefold Increase ◽  
Input Demand ◽  
Level Production ◽  
The U.S

Energy use in U.S. production of food and fiber is extensive and has increased rapidly. A threefold increase occurred from 1940 to 1970 (Carter and Yonde). Food and fiber production accounted for about 13 percent of the total energy consumed in the U.S. in 1980 (Duncan and Webb). Of the total energy use in food and fiber production, farm level production directly consumes about 21 percent (U.S. Senate Committee on Agriculture and Forestry).

scholarly journals Effect of Liberalized U.S.-Mexico Dry Onion Trade: A Spatial and Intertemporal Equilibrium Analysis

1996 ◽  
Vol 28 (1) ◽  
pp. 135-147 ◽  
Author(s):  
Stephen Fuller ◽  
Melanie Gillis ◽  
Houshmand A. Ziari
Keyword(s):  
Free Trade ◽  
North American ◽  
Equilibrium Model ◽  
Equilibrium Analysis ◽  
Farm Level ◽  
The North ◽  
Storage Methods ◽  
Intertemporal Equilibrium ◽  
The Impact ◽  
The U.S

AbstractA spatial, intertemporal equilibrium model of the North American dry onion economy is constructed to analyze the impact of liberalized U.S.-Mexico trade. In a free-trade environment, exports of Mexican onions to the U.S. are projected to increase about 50%, while Mexico's share of the U.S. market increases from 8.7 to 12.8%. Farm-level prices in the U.S. are projected to decline 8.9%, while production declines 2.4%. The effect of free trade on U.S. producers is disproportional across regions. Northwest storage onion producers experience the greatest decline in production; however, analysis suggests that improved storage methods may offset a portion of the unfavorable impacts of liberalized trade on these producers. In spite of the unfavorable impact of free trade on U.S. dry onion producers, the industry would not be economically devastated.

scholarly journals Deviations from normal distributions in artificial and real time series: a false positive prescription

2019 ◽  
Vol 489 (2) ◽  
pp. 2117-2129 ◽  
Author(s):  
Paul J Morris ◽  
Nachiketa Chakraborty ◽  
Garret Cotter
Keyword(s):  
Time Series ◽  
False Positive ◽  
Functional Form ◽  
False Positive Rate ◽  
Light Curves ◽  
Artificial Light ◽  
Positive Rate ◽  
Functional Forms ◽  
Distribution Of Power ◽  
Normally Distributed

ABSTRACT Time-series analysis allows for the determination of the Power Spectral Density (PSD) and Probability Density Function (PDF) for astrophysical sources. The former of these illustrates the distribution of power at various time-scales, typically taking a power-law form, while the latter characterizes the distribution of the underlying stochastic physical processes, with Gaussian and lognormal functional forms both physically motivated. In this paper, we use artificial time series generated using the prescription of Timmer & Koenig to investigate connections between the PDF and PSD. PDFs calculated for these artificial light curves are less likely to be well described by a Gaussian functional form for steep (Γ⪆1) PSD indices due to weak non-stationarity. Using the Fermi LAT monthly light curve of the blazar PKS2155-304 as an example, we prescribe and calculate a false positive rate that indicates how likely the PDF is to be attributed an incorrect functional form. Here, we generate large numbers of artificial light curves with intrinsically normally distributed PDFs and with statistical properties consistent with observations. These are used to evaluate the probabilities that either Gaussian or lognormal functional forms better describe the PDF. We use this prescription to show that PKS2155-304 requires a high prior probability of having a normally distributed PDF, $P(\rm {G})~$ ≥ 0.82, for the calculated PDF to prefer a Gaussian functional form over a lognormal. We present possible choices of prior and evaluate the probability that PKS2155-304 has a lognormally distributed PDF for each.

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