On the marginal value of swimming in woodland caribou

Ecology ◽  
2021 ◽  
Author(s):  
Quinn M.R. Webber ◽  
Jack G. Hendrix ◽  
Alec L. Robitaille ◽  
Eric Vander Wal

Ecography ◽  
2000 ◽  
Vol 23 (4) ◽  
pp. 466-478 ◽  
Author(s):  
W. James Rettie ◽  
Francois Messier


2010 ◽  
Vol 12 (2) ◽  
pp. 153
Author(s):  
Sulhan

Penelitian ini menggunakan metode survei dengan melibatkan 120 Rumah Tangga Petani (RTP) yang ditentukan secara acak sederhana dari 170 RTP. Data yang dikumpulkan adalah tingkat penggunaan lahan dan pupuk urea pada setiap RTP. Alat analisis yang digunakan adalah Fungsi Produksi Cobb-Douglas dengan tujuan untuk mendapatkan tingkat elastisitas penggunaan lahan dan pupuk urea (bi). Selanjutnya untuk mengetahui tingkat efisiensi penggunaan lahan dan pupuk urea digunakan alat analisis Efficiency Index (EI). EI adalah rasio antara Marginal Value Product (MVP) dan Marginal Factor Cost (MFC). Jika EI = 1, maka tingkat penggunaan lahan dan pupuk urea efisien; jika EI > 0, tingkat penggunan lahan dan pupuk urea belum efisien; dan jika EI < 0, tingkat penggunaan lahan dan pupuk urea tidak efisien. Hasil penelitian menunjukkan bahwa penggunaan lahan dan pupuk urea dalam usahatani padi di Bau-Bau memiliki EI > 1 yang berarti bahwa tingkat penggunaan kedua faktor produksi tersebut masih kurang karena dari setiap penambahan satu unit faktor produksi tersebut akan memberikan penerimaan yang lebih besar daripada besarnya biaya yang dikeluarkan. Oleh karenanya penggunaan kedua faktor produksi tersebut belum efisien sehingga disarankan untuk ditingkatkan penggunaannya.



HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 452a-452
Author(s):  
Richard Buchner ◽  
Seeley Mudd ◽  
Bruce Carroll ◽  
Mark Gilles

Overall profitability is a major goal in successful prune production and a major component in any prune management system. Large prune crops in 1996 and 1997 have stimulated considerable interest in undersize fruit. Undersize prunes currently have marginal value and may represent a net loss because of costs to haul, dry, and to market order payments on low value prunes. One technique to control delivery size is to field size at harvest. Field sizing involves installing size-sorting devices on harvesters, which allow small prunes to fall out while valuable fruit is collected. Field sizing is considered a “risky” strategy because of the potential to remove prunes with economic value. During the 1997 harvest, 21 infield harvest sizing evaluations were made in prune orchards throughout Tehama county. The first evaluation occurred on 12 Aug. 1997, at the start of prune harvest. The final evaluation was done on 5 Sept. 1997, at the tail end of harvest. The objective was to sample throughout the harvest period to test field sizing under various sugar, size, and fruit pressure scenarios. The test machine was 1-inch bar sizer. Of the 21 sample dates, undersize fruit was clearly not marketable in 20 of the 21 samples. Discarded fruit averaged 133 dry count per pound. Only one sample out of 21 may have had market value at 86 dry count per pound. Although small in size, these prunes had very high sugar content contributing to their dry weight. In this evaluation, a 1-inch bar sizer did a good job of separating fruit with and without market value under the 1997 price schedule. As harvest date becomes later and soluble solids increase, the chances of sorting out marketable prunes also increases.



Author(s):  
Michael O'Connor Keefe ◽  
Robert L. Kieschnick


2021 ◽  
pp. 232102222098516
Author(s):  
Dipankar Das

The paper puts forth a notion and derives a special type of production function where labour is an indivisible factor and is in the integer space. Thus, Newtonian calculus is not an appropriate method of deriving the marginal value because limit point does not exist. This shows that indivisibility determines the output elasticity. In the first part, the paper propounds a notion regarding how indivisibility determines curvature of the production function. In the second part, the paper incorporates the findings within a production function and derives a new type accordingly. Moreover, it formally derives the standard wage equation considering all the entitlements of labour, namely (a) normal wages, (b) interest and (c) rent of ability. So far, no such mathematical proof is there to support this wage composition. This paper, for the first time, derives this wage equation considering indivisibility of labour. JEL Classifications: J23, J24, J31, D24, C61, E24, L8



Author(s):  
Poppy M. Jeffries ◽  
Samantha C. Patrick ◽  
Jonathan R. Potts

AbstractMany animal populations include a diversity of personalities, and these personalities are often linked to foraging strategy. However, it is not always clear why populations should evolve to have this diversity. Indeed, optimal foraging theory typically seeks out a single optimal strategy for individuals in a population. So why do we, in fact, see a variety of strategies existing in a single population? Here, we aim to provide insight into this conundrum by modelling the particular case of foraging seabirds, that forage on patchy prey. These seabirds have only partial knowledge of their environment: they do not know exactly where the next patch will emerge, but they may have some understanding of which locations are more likely to lead to patch emergence than others. Many existing optimal foraging studies assume either complete knowledge (e.g. Marginal Value Theorem) or no knowledge (e.g. Lévy Flight Hypothesis), but here we construct a new modelling approach which incorporates partial knowledge. In our model, different foraging strategies are favoured by different birds along the bold-shy personality continuum, so we can assess the optimality of a personality type. We show that it is optimal to be shy (resp. bold) when living in a population of bold (resp. shy) birds. This observation gives a plausible mechanism behind the emergence of diverse personalities. We also show that environmental degradation is likely to favour shyer birds and cause a decrease in diversity of personality over time.



Author(s):  
Wataru Nagatomo ◽  
Junko Saito ◽  
Naoki Kondo

Abstract Background In light of recent theories in behavioural economics, an intervention program with monetary incentives could be effective for helping patrons order healthy food, even if the incentive is small and less than one’s perceived marginal value. Methods In this single-arm cluster crossover trial at 26 local restaurants, a 1-week campaign offered a 50-yen (approximately 0.5 US dollars) cash-back payment to customers ordering vegetable-rich meals, while no pre-order incentives were offered during the control period. Results In total, 511 respondents out of 7537 customers (6.8%), and 704 respondents out of 7826 customers (9.0%), ordered vegetable-rich meals during the control and intervention periods, respectively. During the intervention period, the covariate-adjusted proportion of vegetable-rich meal orders was 1.50 times higher (95% confidence interval [CI]: 1.29 to 1.75), which increased daily sales by 1.77 times (95% CI: 1.11 to 2.83), even when subtracting the cost of cash-back payments. Respondents who reported spending the least amount of money on eating out (used as a proxy measure for income) were the least likely to order vegetable-rich meals during the control period. However, these individuals increased their proportion of purchasing such meals during the intervention period (a 3.8 percentage point increase (95% CI: 2.82 to 4.76) among those spending the least vs a 2.1 percentage point increase (95% CI: 1.66 to 2.62) among those spending the most; P for interaction = 0.001). Similarly, irregular employees exhibited a larger increase (+ 5.2 percentage points, 95% CI: 4.54 to 5.76) than did regular workers (− 1.4, 95% CI: − 1.66 to − 1.05, P for interaction = 0.001). Conclusions A program with an immediate low-value monetary incentive could be a public health measure for reducing inequalities in making healthy food choices. Trial registration UMIN Clinical Trials Registry, UMIN000022396. Registered 21 May 2016.



Economica ◽  
2007 ◽  
Vol 74 (296) ◽  
pp. 650-663 ◽  
Author(s):  
JOHN HOROWITZ ◽  
J. LIST ◽  
K. E. McCONNELL
Keyword(s):  


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