Towards optimal designs for hedgerow olive orchards

2006 ◽  
Vol 57 (10) ◽  
pp. 1067 ◽  
Author(s):  
David J. Connor
Keyword(s):  
Shoot Growth ◽  
Growth Habit ◽  
Incident Radiation ◽  
Optimal Designs ◽  
Threshold Values ◽  
Row Width ◽  
Key Sites ◽  
And Performance ◽  
Fruit Formation ◽  
Radiation Research

An analysis of row height, row width, canopy slope, and alley width of hedgerow olive orchards was conducted to identify combinations that maximise productivity while allowing access to machinery for management. This objective requires maximising both the interception of incident solar radiation and its distribution over the canopy surface for productivity. For maximum productivity, all foliage must be illuminated above threshold values for the critical step in the shoot growth – floral initiation – flowering – fruit formation – fruit filling reproductive sequence. The key sites for adequate illumination are the bases of the canopy walls. For canopies with row height and alley width combinations that provide threshold illumination at the bases of the canopy walls, the area of productive foliage per unit orchard area is inversely related to row width because incident radiation received by broad canopy tops is better spread at smaller irradiance over more canopy wall. The analysis revealed that canopies of equal productivity can be formed with a range of combinations of height, slope, and alley width, and that optimal combinations are responsive to threshold values in the range 20–30% of incident radiation. Research is required to establish threshold values and the limits to row height and row width consistent with year-to-year production of reproductive shoots. The latter requires attention to cost and performance of machinery, the growth habit of the tree, and its response to pruning.

Initiation, Development and Anatomy of Lignotubers in Some Species of Eucalyptus

1984 ◽  
Vol 32 (4) ◽  
pp. 415 ◽  
Author(s):  
DJ Carr ◽  
R Jahnke ◽  
SGM Carr
Keyword(s):  
Analytical Study ◽  
Growth Habit ◽  
Stem Growth ◽  
Morphological Development ◽  
Alternative Pathways ◽  
Stem Wood ◽  
Initial Survey ◽  
And Performance ◽  
Lateral Fusion ◽  
Taxonomic Groups

An initial survey of the diversity of early lignotuber development in Eucalyptus and an analytical study of the anatomy of young lignotubers and the seedling stem are presented. Studies of the early stages of the morphological development of the lignotuber in 13 species, representative of five taxonomic groups, resulted in the recognition of four modes of lignotuber initiation. The importance to lignotuber formation of the presence of a suite of accessory buds, adaxial to the axillary bud, is emphasized but lignotuber initiation is not in all cases associated with these buds. Lignotuber buds are derived by branching from existing buds, ultimately from the accessory buds of the node. Following its initiation, the possibilities of later morphological development of the lignotuber are discussed. Lignotuber growth may dominate over stem growth and the lignotubers at a node may then fuse laterally to encircle the stem. Stem growth, on the other hand, may dominate over lignotuber growth and the lignotuber then appears to regress. The consequences for the growth habit of the plant of these alternative pathways of development are outlined. The wood of young lignotubers (and that of the swollen hypocotyl) is shown to be different in composition and in the sizes of its elements from that of seedling stem wood; these differences owe their origin to differences in the nature and performance of the cambia of the lignotuber and stem. In lateral fusion of the lignotubers at a node, and their upward and downwards extension over the stem, e.g. over the hypocotyl, stem cambial initials are either progressively lost or, more likely, converted to lignotuber-type initials. The possibility of the reverse process occumng in stem dominance is discussed.

scholarly journals Social-Class Disparities in Higher Education and Professional Workplaces: The Role of Cultural Mismatch

2018 ◽  
Vol 28 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Nicole M. Stephens ◽  
Sarah S. M. Townsend ◽  
Andrea G. Dittmann
Keyword(s):  
Higher Education ◽  
Social Class ◽  
Working Class ◽  
Cultural Models ◽  
Cultural Barriers ◽  
Cultural Barrier ◽  
Cultural Mismatch ◽  
Cultural Ideal ◽  
Key Sites ◽  
And Performance

Differences in structural resources and individual skills contribute to social-class disparities in both U.S. gateway institutions of higher education and professional workplaces. People from working-class contexts also experience cultural barriers that maintain these disparities. In this article, we focus on one critical cultural barrier—the cultural mismatch between (a) the independent cultural norms prevalent in middle-class contexts and U.S. institutions and (b) the interdependent norms common in working-class contexts. In particular, we explain how cultural mismatch can fuel social-class disparities in higher education and professional workplaces. First, we explain how different social-class contexts tend to reflect and foster different cultural models of self. Second, we outline how higher education and professional workplaces often prioritize independence as the cultural ideal. Finally, we describe two key sites of cultural mismatch—norms for understanding the self and interacting with others—and explain their consequences for working-class people’s access to and performance in gateway institutions.

scholarly journals CHARACTERISTICS OF OMEGA-OPTIMIZED PORTFOLIOS AT DIFFERENT LEVELS OF THRESHOLD RETURNS

2014 ◽  
Vol 12 (2) ◽  
pp. 245-265 ◽  
Author(s):  
Renaldas Vilkancas
Keyword(s):  
Portfolio Optimization ◽  
Risk Measures ◽  
High Threshold ◽  
Portfolio Performance ◽  
Threshold Values ◽  
Portfolio Returns ◽  
Upside Risk ◽  
And Performance ◽  
Risk Free Rate ◽  
Different Levels

There is little literature considering effects that the loss-gain threshold used for dividing good and bad outcomes by all downside (upside) risk measures has on portfolio optimization and performance. The purpose of this study is to assess the performance of portfolios optimized with respect to the Omega function developed by Keating and Shadwick at different levels of the threshold returns. The most common choices of the threshold values used in various Omega studies cover the risk-free rate and the average market return or simply a zero return, even though the inventors of this measure for risk warn that “using the values of the Omega function at particular points can be critically misleading” and that “only the entire Omega function contains information on distribution”. The obtained results demonstrate the importance of the selected values of the threshold return on portfolio performance – higher levels of the threshold lead to an increase in portfolio returns, albeit at the expense of a higher risk. In fact, within a certain threshold interval, Omega-optimized portfolios achieved the highest net return, compared with all other strategies for portfolio optimization using three different test datasets. However, beyond a certain limit, high threshold values will actually start hurting portfolio performance while meta-heuristic optimizers typically are able to produce a solution at any level of the threshold, and the obtained results would most likely be financially meaningless.

scholarly journals Plant Population Affects Yield and Fruit Size of Pumpkin

HortScience ◽  
1999 ◽  
Vol 34 (6) ◽  
pp. 1076-1078 ◽  
Author(s):  
Stephen Reiners ◽  
Dale I.M. Riggs
Keyword(s):  
Growth Habit ◽  
Plant Competition ◽  
Fruit Size ◽  
Field Studies ◽  
Plant Population ◽  
Lower Yield ◽  
Marketable Yield ◽  
Plant Populations ◽  
Fruit Number ◽  
Row Width

Field studies were conducted in 1996 on two pumpkin (Cucurbita pepo L.) cultivars, `Howden' (vining-type growth habit) and `Wizard' (semi-bush growth habit), at two locations to determine the effect of plant population and row width on marketable yield. Increasing plant populations from 2990 to 8960 plants per hectare resulted in significantly greater fruit number and yield at both locations and for both varieties. Average fruit size declined at the highest populations. Increasing row width from 1.8 to 3.6 m resulted in a slight but significant decrease in number of fruit per hectare with no effect on other yield parameters. At one location, the effect of row width on yield and number of fruit per hectare depended on the population. At low populations, row width did not influence yield or fruit number; at high populations, wide rows produced lower yield and fewer fruit than narrow rows. The results demonstrate that growers may increase pumpkin yield by increasing plant populations but should use narrower row widths and wider in-row spacing. Growers who choose higher populations should ensure that all inputs are optimized to reduce potential plant-to-plant competition and use regionally adapted cultivars.

Low temperature effects on growth and physiology specific to a "grass-clump" dwarf wheat hybrid

1972 ◽  
Vol 50 (2) ◽  
pp. 253-261 ◽  
Author(s):  
J. D. Mahon ◽  
D. T. Canvin
Keyword(s):  
Low Temperature ◽  
Shoot Growth ◽  
Growth Habit ◽  
Temperature Response ◽  
Dry Weight ◽  
Growth Responses ◽  
Meristematic Region ◽  
Meristematic Activity ◽  
Dwarf Wheat ◽  
Induced Changes

The growth habit of "grass-clump" dwarf wheat plants can be affected by extremely short 16° treatments if given repeatedly. To localize the earliest growth responses in plants of one such hybrid (Mql × KF 1), the temperature sensitivity of plants of different ages, and the earliest temperature-induced changes in growth, development, and shoot physiology were investigated and compared with the responses of normal wheat plants.Mql × KF 1 plants growing at 26° responded to progressively shorter 16° treatments as they aged and plants exposed to 16° after 10 days growth at 26° were unable to recover from low temperature treatments of 3–5 days duration. Although shoot growth (as dry weight) of Mql × KF 1 stopped abruptly after 7 days at 16°, root growth (as dry weight) continued for at least 15 days. The rates of CO2 and water vapor exchange in individual leaves responded to low temperature similarly in both the dwarf and normal plants and did not markedly decrease until after 4 days at 16°. The most rapid low temperature response specific to Mql × KF 1 plants was cessation in primary tiller development immediately after the beginning of 16° exposure. It is proposed that the primary 16° effect is on the shoot meristematic region and that other changes in growth and physiology result from the lack of meristematic activity in the young growing region.

Parameter Optimization of Decentralized OS-CFAR System Based Modified PSO Method

2012 ◽  
Vol 532-533 ◽  
pp. 881-886
Author(s):  
Pan Zhi Liu ◽  
Ruo Yu Pan ◽  
Guo Fang Guo
Keyword(s):  
Optimization Problem ◽  
Detection System ◽  
Pso Algorithm ◽  
Optimization Method ◽  
Fusion Center ◽  
Threshold Values ◽  
Cfar Detection ◽  
Computation Technique ◽  
And Performance ◽  
Ordered Statistics

For decentralized ordered statistics (OS) constant false alarm ration (CFAR) detection system, the parameter estimation and performance analysis in complicated detection condition is a typical nonlinear optimization problem. Owing to the nonlinear property of distributed OS-CFAR detection system, it is seriously difficult to obtain optimal threshold values using some optimization method at the fusion center. This paper provides a novel solution based on an effective and flexible particle swarm optimization (PSO) algorithm. As a novel evolutionary computation technique, PSO has attracted much attention and wide applications, owing to its simple concept, easy implementation and quick convergence. Using this approach, all system parameters can be optimized simultaneously. The simulation results show that the proposed approach can achieve effective performances with the above method.

scholarly journals Pareto simulated annealing for the design of experiments: illustrated by a gene expression study

2012 ◽  
Vol 37 (3) ◽  
pp. 199-221 ◽  
Author(s):  
Penny Sanchez ◽  
Gary Glonek ◽  
Andrew Metcalfe
Keyword(s):  
Gene Expression ◽  
Simulated Annealing ◽  
Minimum Cost ◽  
Optimal Designs ◽  
Expression Study ◽  
Expression Studies ◽  
Optimal Values ◽  
Gene Expression Studies ◽  
And Performance ◽  
Pareto Simulated Annealing

Abstract Experimental design is concerned with the problem of allocating resources within an experiment to ensure that objectives of the experiment are achieved at the minimum cost. This paper focuses on the generation of optimal or near-optimal designs for large and complex experiments where it is infeasible to carry out an ex- haustive search of the design space. Optimal designs for gene expression studies, aimed at investigating the behaviour of genes, are considered, where the optimality criterion employed is Pareto optimality. We develop an adaptation of the metaheuris- tic method of Pareto simulated annealing to generate an approximation to the set of Pareto optimal designs for large and complex experiments. We develop algorithms that utilise response surface methodology to search systematically for the optimal values of parameters associated with Pareto simulated annealing and performance is evaluated using quality measures.

scholarly journals Orchard Variation in Micropropagated Trees of `Redspur Delicious' Apple

HortScience ◽  
1997 ◽  
Vol 32 (5) ◽  
pp. 935-936 ◽  
Author(s):  
Richard H. Zimmerman
Keyword(s):  
Shoot Growth ◽  
Potential Problem ◽  
Growth Habit ◽  
Fruit Yield ◽  
Tree Size ◽  
Clonal Variation ◽  
First Year ◽  
Clonal Fidelity

Micropropagated trees of `Redspur Delicious' apple (Malus ×domestica Borkh.), planted as small, actively growing trees in May 1982, lacked uniformity in tree size, appearance, and flowering by the spring of 1986. Only four of the 18 trees had a typical spur-type growth habit; these four trees had 80% more spurs per meter of shoot, 8 to 10 times as many flowers the first year of flowering and 9.5-fold higher early fruit yields, but were 40% smaller after 14 years in the orchard and had 25% less cumulative fruit yield than the nonspur types. Shoots from the spur-type trees were recultured in 1988 and the resulting trees planted in an orchard in 1990. These latter trees were uniform in appearance and all had typical spur-type growth, with about 30% more spurs per meter of shoot growth than the spur-type trees from which they were propagated. Micropropagating spur-type apples from previously micropropagated trees that have maintained clonal fidelity may overcome the potential problem of clonal variation in orchard planted micropropagated trees.

scholarly journals 518 PB 456 INHERITANCE OF PROCUMBENT GROWTH CHARACTERISTICS AMONG HYBRIDS OF `CIPO' SWEET ORANGE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 505f-505
Author(s):  
Kim D. Bowman
Keyword(s):  
Related Species ◽  
Citrus Sinensis ◽  
Shoot Growth ◽  
Growth Form ◽  
Growth Habit ◽  
Sweet Orange ◽  
Growth Characteristics ◽  
Citrus Tree ◽  
Breeding Programs ◽  
Tree Characteristics

Citrus tree size and growth form are important traits that can be influenced by the genotype of both scion and rootstock cultivars. However, there have been very few reports of size or growth habit traits within Citrus or sexually compatible genera that might be transmitted genetically in breeding programs. A procumbent growth habit has been described for `Cipo' (Citrus sinensis [L.] Osbeck), a unique sweet orange cultivar maintained in the USDA germplasm repository. Sexual hybrids were produced between this selection and four related species, and these progenies were evaluated for two distinct traits associated with the unusual growth habit of `Cipo'. Inheritance of both drooping petiole and horizontal shoot growth were observed among the `Cipo' hybrids. Investigations are continuing on these four populations to verify segregation patterns and identify individuals possessing favorable combinations of growth habit with other desirable tree characteristics.

scholarly journals Variation in Micropropagated Trees of `Redspur Delicious' Apple

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 871F-871 ◽  
Author(s):  
Richard H. Zimmerman
Keyword(s):  
Shoot Growth ◽  
Growth Habit ◽  
Shoot Length ◽  
Tree Size ◽  
Cumulative Yield

Small actively growing micropropagated trees of `Redspur Delicious' apple (Malus xdomestica Borkh.) were planted in an orchard at the end of May 1982. By Spring 1986, a lack of uniformity in tree size, appearance, and flowering was obvious. Only four of the 18 trees had a typical spur-type growth habit. These four trees had significantly more spurs per unit of shoot length, flowered sooner, had higher early fruit yields, and remained significantly smaller after 13 years in the orchard, but had significantly less cumulative yield than the nonspur types. Shoots from the spur-type trees were recultured in 1988 and the resulting trees planted in an orchard in 1990. These latter trees were uniform in appearance and all had typical spur-type growth with ≈30% more spurs per meter of shoot growth than the original trees from which they were propagated.

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