bluuebunny/crossref_metadata_2025 huggingface dataset:
Summer Garden Programs Improve Children’s Food Knowledge and Preferences: Evidence Using Stated and Revealed Preference Measures
Authors: Brown Joanna , Colson Gregory , de La Serre Claire B. , Magnan Nicholas
Published: October 2019

One reason for excessive body weight among youth is poor eating choices. Garden-based programs have the potential to educate children about fruits and vegetables and healthy eating generally, and improve their food preferences. This study examines the impacts of two community-based summer garden programs in Atlanta, GA, on children aged 5–14 years (n = 71). These programs spanned 1 to 2 weeks and included daily gardening activities and nutritional education. The study employs a pre- and postprogram questionnaire and a food choice experiment to evaluate changes in knowledge about and preferences for healthy and unhealthy foods. Results show that the programs substantially and significantly increased knowledge about nutrients (P < 0.01), plants (P < 0.1), and healthy foods (P < 0.01). The programs also increased the number of fruits and vegetables participants tried (P < 0.1) and their propensity to make healthy choices in the food experiment (P < 0.1). Regression analysis shows program impacts on plant knowledge (P < 0.1) and fruits and vegetables tried (P < 0.1) to be lower for African American children (n = 38) and all other program impacts to be statistically homogenous. At least in the short term, garden programs such as these can alter children’s preferences and decisions regarding healthy eating. More research is needed to see if these effects persist and ultimately improve health outcomes into adulthood.
Biodegradable Plastic and Fabric Mulch Performance in Field and High Tunnel Cucumber Production
Authors: Wortman Sam E. , Kadoma Ignatius , Crandall Michael D.
Published: October 2019

Polyethylene mulch use is common in vegetable production, but disposal of mulch is problematic for growers and of significant environmental concern. Biodegradable fabrics and plastic films are compostable and can be incorporated into the soil at the end of the growing season, but questions remain about the durability, performance, and rate of decomposition of these products after soil incorporation. Three trials were conducted in field and high tunnel cucumber (Cucumis sativus) cropping systems to compare performance and decomposition after use among two bioplastic films and four experimental spunbond, nonwoven biofabrics. Soil temperature and moisture, mulch durability and deterioration, weed suppression, and crop yield data were collected in each growing season. All biomulches were soil incorporated after the growing season and recovered up to 11 months after incorporation to estimate relative rates of decomposition. One bioplastic film increased field soil temperature by 2 °C in 2013, but temperatures under the biofabrics were not different from bare soil. Bioplastics and biofabrics increased soil moisture relative to bare soil. Bioplastic films were less durable and deteriorated sooner than biofabrics, especially in the field environment (as early as 34 days after transplanting). All biomulches suppressed weed emergence relative to bare soil, but weeds were visibly growing beneath the most translucent biofabric. Marketable yield of cucumber was trending highest in the most durable and opaque biofabric (1827 g·m−2), but was not significantly different from weed-free bare soil (1251 g·m−2). Relative rate of mulch decomposition up to 11 months after soil incorporation was not different among bioplastic and biofabric products. Results suggest that the tested biofabrics will be most useful to growers when soil warming is not necessary (e.g., warm climates), but moisture conservation and weed control are critical (e.g., organic cropping systems). Moreover, biofabrics are permeable and may be useful to growers dependent on sprinkler irrigation or rainfall to meet crop water demands.
Growth Characteristics of Bahiagrass Roots Treated with Micronutrients, Rare Earth Elements, and Plant Hormones
Authors: Liu Ying , Song Huawei , Zhang Juming , Richardson Michael D.
Published: October 2019

Bahiagrass (Paspalum notatum) is widely used for slope protection and water and soil conservation in southern China. The plants develop an extensive root system that plays a crucial role in the protection of both soil and water. However, little is currently known about the factors that influence early root growth in bahiagrass. Here, the effects of boron (B), calcium (Ca), iron (Fe), lanthanum (La), cerium (Ce), salicylic acid (SA), and melatonin (MLT) on root growth characteristics were examined. Bahiagrass seedlings were grown in 1/25 strength modified Hoagland nutrient solution supplemented with boric acid, calcium chloride, ferric ethylenediaminetetraacetic acid (Fe-EDTA), lanthanum chloride, cerium chloride, SA, or MLT. Root lengths, root surface areas, and the number of root tips were analyzed using a root scanning system after 2, 4, and 6 days of treatment. We found significant effects on root growth after some treatments. Thus, 0.270 or 0.360 mm B for 2 days enhanced root tip number, whereas 0.15 mm Fe for 6 days increased root surface area. Although 3 or 5 mm Ca caused an increase in root tip numbers, the root length was reduced. The addition of La to the nutrient solution significantly increased root length and surface area, and addition of Ce increased root surface area and root tip numbers. Root growth characteristics were optimal after 0.3 μm La for 6 days or 1.0 μm La for 4 days. For Ce treatment, optimal root characteristics were observed at 0.5 μm Ce for 6 days. Root tip numbers increased after 0.1 or 1.0 μm MLT for 6 days, whereas SA treatment reduced the root length, surface area, and root tip numbers. Overall, the analyses indicate that treatment with B, Fe, La, Ce, and MLT benefited root growth in bahiagrass seedlings.
Addition of Forchlorfenuron to Spray Pollination Media Increases Fruit Set in ‘Hosui’ Japanese Pear
Authors: Sakamoto Daisuke , Kusaba Shinnosuke , Nakamura Yuri
Published: October 2019

The effects on fruit set of adding forchlorfenuron (CPPU) to media in which pollen grains were suspended and used for spray pollination was investigated in ‘Hosui’ japanese pear (Pyrus pyrifolia). The percentages of fruit set after spray pollination were lower than those after hand pollination; however, media with 2 or 10 mg·L−1 CPPU used for spray pollination resulted in greater percentages of fruit set than media without CPPU. The media with CPPU also resulted in higher levels of pollen germination compared with the medium without CPPU; however, the number of seeds per fruit with CPPU treatment tended to be almost the same or less than for fruit without CPPU treatment. From these results, the higher levels of fruit set by CPPU might not be due to the high germination rate of the pollen grains but due to the induction of partial parthenocarpic properties. The medium with 10 mg·L−1 CPPU gave the highest levels of fruit set, but the fruit had abnormally thickened and enlarged calyxes, and the fruit shape tended to be deformed at ≈21 days after flowering. In addition, all of the harvested fruit were calyx-perpetual fruit in which the calyx remains until harvest time. Fruit treated with 2 mg·L−1 CPPU also yielded calyx-perpetual fruit with high frequency, but the fruit had normal calyxes and the fruit shape tended to be more normal. Thus, we conducted experiments focusing on the medium containing 2 mg·L−1 CPPU. Although the results were variable from year to year, more than 70% of hand-pollinated flowers set fruit during the 3-year study; this level of fruit production is sufficient for practical use. Thus, spray pollination using a medium with 2 mg·L−1 CPPU is an acceptable method for pollinating ‘Hosui’ japanese pear.
Exclusion of the Brown Marmorated Stink Bug from Organically Grown Peppers Using Barrier Screens
Authors: Dobson Rachelyn C. , Rogers Mary , Moore Jennifer L.C. , Bessin Ricardo T.
Published: October 2019

The brown marmorated stink bug (Halyomorpha halys) is a nonnative insect that damages vegetables and other crops in the United States. Because of the current lack of effective control options for organic growers to combat this pest, barrier screens with different mesh sizes were evaluated in their ability to exclude the brown marmorated stink bug, provide entry to beneficial species, and to produce a high percentage of marketable yield. Barrier screens with 1/6-, 1/8-, and 1/25-inch mesh sizes, along with unscreened controls, covered ‘Aristotle’ bell pepper (Capsicum annuum) plants at field sites in Kentucky and Tennessee in 2013–14. In Kentucky, where brown marmorated stink bug pressure was low, overshading decreased the marketable yield under dark, 1/25-inch mesh screens in 2013. Outbreaks of aphids (Aphididae) under light-colored, 1/25-inch mesh plots in 2014 suggest a higher risk of secondary pests proliferating under these screens. In Tennessee, where brown marmorated stink bug pressure was higher and light colored, 1/25-inch mesh screens were tested in 2013–14, the 1/25-inch mesh plots produced the highest yield, due to the general exclusion of insects and protection from sunscald. In areas with small brown marmorated stink bug populations, lighter colored, and/or wider meshes (1/8-inch or 1/6-inch) may be required to allow the entry of sunlight and beneficial species. In areas with higher brown marmorated stink bug pressure, finer meshes (1/25-inch) may be appropriate to exclude larger populations of pests and to protect the crop from sunscald.
Impact of Cross- and Self-pollination on Fruit Set, Fruit Size, Seed Number, and Harvest Timing Among 13 Southern Highbush Blueberry Cultivars
Authors: Taber Sarah K. , Olmstead James W.
Published: October 2019

Cross-pollination has been associated with improved fruit set, weight, and shortened time to ripening in southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrids)]. Because of this, growers commonly plant two or more cultivars in small blocks to facilitate cross-pollination. However, many SHB cultivars may vary in the degree of improvement in each parameter after cross-pollination. Understanding the impacts of cross-pollination on a particular cultivar is crucial to forming planting recommendations, particularly as growers begin to transition to fields designed for machine harvest where large solid blocks would increase the harvest efficiency. The objective of this study was to examine the effects of cross- and self-pollination among 13 commonly planted or newly released SHB cultivars. Cross-pollination typically improved fruit set, fruit weight, and seed number while decreasing the average days to harvest. Cross-pollinated fruit always weighed more than self-pollinated fruit from the same cultivar, which was highly correlated to seed number per fruit. Although there was variation for each trait, interplanting with another unrelated cultivar sharing a similar bloom time remains the best recommendation to ensure early, high yield among these SHB cultivars.
Reestablishment of Perennial Ryegrass in Lawns Damaged by Diesel and Hydraulic Fluid Spills
Authors: Yuan Longyi , Gao Yang , Li Deying
Published: October 2019

Petroleum-based spills on turfgrass often occur during lawn care maintenance. Damage caused by diesel and hydraulic fluid is particularly difficult to correct. The objective of this study was to compare the effectiveness of combining mulching with remediation for reseeding spilled areas in lawns. Diesel and hydraulic fluid were applied to plots at a rate of 15 L·m−2. Immediately after the spill treatments, two liquid humic amendments and an activated flowable charcoal were applied at a volume rate of 8 L·m−2, respectively, with tap water/dishwashing detergent used as a control. Nitrate nitrogen was added to each remediation treatment to facilitate remediation. The spilled areas were reseeded with perennial ryegrass (Lolium perenne) and then mulched with biochar, peat pellets, and paper pellets, respectively. At 6 weeks after seeding, humic amendment 1 and activated charcoal showed better turf quality than humic amendment 2. Peat pellet mulching presented better turf quality than other mulching methods. Reseeding perennial ryegrass and mulching with peat pellets after remediation with either humic amendment 1 or activated charcoal resulted in acceptable turf quality 6 weeks after diesel and hydraulic fluid spills. Therefore, this reestablishment method is recommended as a practical way to deal with diesel or hydraulic fluid spills in cool-season turfgrasses.
Shade Effect on Growth and Productivity of Tomato and Chili Pepper
Authors: Masabni Joseph , Sun Youping , Niu Genhua , Del Valle Priscilla
Published: October 2019

Southern U.S. states such as Texas experience high temperatures and intense solar radiation during the summer production season. Use of shadecloth is common in Spain and other Mediterranean countries and is becoming popular with homeowners or small-acreage farmers in Texas. Little information is available on the applicability of using shadecloth on tomato (Solanum lycopersicum) and chili pepper (Capsicum annuum) in the warm climate of Texas. The effects of two shade nets differing in shading intensity on growth, chlorophyll fluorescence, and photosynthesis of ‘Celebrity’ tomato and ‘Sweet Banana’ chili pepper was investigated from May to Aug. 2014. Plants were grown in 50% shade, 70% shade, or full sun. Compared with the unshaded control, tomato grown in 50% shade had similar yield and shoot fresh and dry weight and less photochemical stress. The 50% shade reduced number and weight of unmarketable tomato fruit. Similar results were obtained with chili pepper except for lower numbers of marketable fruit. The 70% shade significantly reduced yield parameters of both tomato and chili pepper. Both 50% and 70% shadecloth reduced leaf temperatures of tomato and chili pepper with variable results in June and July. Growth index [(height + width 1 + width 2) ÷ 3] of tomato and chili pepper was the highest with 50% shade, the lowest with full sun, and intermediate with 70% shade. The maximum net photosynthetic rates (Pn) of tomato determined from a Pn to light response curve supported the results on growth and yield. However, the maximum Pn of chili pepper was higher in full sun treatment compared with 50% or 70% shade. The latter two were almost identical. This one growing season study indicated that shading at 50% benefits tomato and chili pepper production in west Texas by reducing heat stress; however, a shading percentage below 50% may be better.
Developing a National Strategic Plan for Consumer Horticulture
Authors: Bradley Lucy K. , Bauske Ellen M. , Bewick Thomas A. , Clark John R. , Durham Richard. E. , Langellotto Gail , Meyer Mary H. , Pooler Margaret , Dorn Sheri
Published: October 2019

Consumer horticulture encompasses a wide array of activities that are practiced by and of interest to the gardening public, garden-focused nongovernmental organizations, and gardening-related industries. In a previous publication, we described the current lack of funding for research, extension, and education in consumer horticulture and outlined the need for a strategic plan. Here, we describe our process and progress in crafting a plan to guide university efforts in consumer horticulture, and to unite these efforts with stakeholders’ goals. In 2015, a steering committee developed a first draft of a plan, including a mission statement, aspirational vision, core values, goals, and objectives. This draft was subsequently presented to and vetted by stakeholders at the 2015 American Society for Horticultural Science Consumer Horticulture and Master Gardeners (CHMG) working group workshop, a 2015 Extension Master Gardener Coordinators’ webinar, and a 2015 meeting in Washington, DC. Feedback received from these events is being used to refine and focus plan goals and objectives. The most recent working draft of the plan can be found on the website, where stakeholders and other interested parties can register to receive updates and to provide input into the process.
Developing Protocols for Fall Sweet Corn Production in the South-central United States
Authors: Kahn Brian A. , Brandenberger Lynn P.
Published: October 2019

Field studies were conducted in Oklahoma from 2010 to 2012 to develop protocols for fall sweet corn (Zea mays) production. Variables examined included a transgenic cultivar that expresses the CryIA(b) toxin from the bacterium Bacillus thuringiensis (Bt) and its nontransgenic near-isoline, seeding rates and planting dates, and various insecticide regimens. We found that, in eastern Oklahoma, a suitable planting window would correspond roughly to the last 2 weeks in July. Within this favorable period and given timely irrigation, it was possible to sow corn to an acceptable stand. A seeding rate ≈1½ times the desired final stand of one plant/ft appeared to be satisfactory. Use of a cultivar (GSS-0966) with genetic resistance to lepidopteran pests was a critical factor for successful production of fall sweet corn. Efforts to produce a crop with a nontransgenic cultivar using insecticides with relatively low mammalian toxicity were unsuccessful. Our experiments support previous recommendations for applying supplemental insecticides to transgenic Bt sweet corn to potentially increase production of “premium” ears by reducing the percentage of ears with severe insect damage (damage >1½ inches from the cob tip). We demonstrated that a spray schedule that rotated two insecticides with intermediate mammalian toxicity (carbaryl and permethrin) was as effective in reducing severe insect damage to ears of ‘GSS-0966’ as a similar schedule that rotated two highly toxic insecticides (esfenvalerate and methomyl).
Evaluation of Shallow Subsurface Drip Irrigation for the Production of Acorn Squash
Authors: Coolong Timothy
Published: October 2019

Subsurface drip irrigation (SDI) has been increasingly used for the production of numerous agronomic crops and a limited number of vegetable crops. To determine the impact of SDI compared with surface drip irrigation (SUR), a study was conducted in 2011 and 2012 with ‘Table Queen’ acorn squash (Cucurbita pepo var. turbinata) with irrigation initiated at 75% and 50% plant available water (PAW). The study was arranged as a factorial randomized complete block design and plants were grown with two irrigation types (SUR or SDI) and two tensiometer-controlled irrigation regimes. Results from 2011 suggested that SDI used less water compared with SUR at each irrigation set point. However, in 2012, significantly more water was used in all treatments due to warmer temperatures and less rainfall. In 2012, SDI used more water than SUR treatments at the same irrigation set point. In 2012, yield was affected by irrigation treatment. Plants grown using SUR irrigating at 75% PAW had greater numbers of fruit compared with other treatments. Furthermore, the highest yielding treatment had more than twice the number of irrigation events than the other treatments though the average lengths of irrigation events were shorter. Although overall yields were greater in 2012, irrigation water use efficiency (iWUE) was lower than in 2011 due to increased water use. These results suggest that while SDI may have some advantages over traditional SUR, environmental factors during growth can significantly impact the efficiency and productivity of each system.
Yield and Quality of Grafted Watermelon Grown in a Field Naturally Infested with Fusarium Wilt
Authors: Moreno Benjamín , Jacob Cristián , Rosales Marlene , Krarup Christian , Contreras Samuel
Published: October 2019

Grafting of seedlings is a technique used for watermelon (Citrullus lanatus) production in many countries. Because of higher costs involved, the use of grafted seedlings can only be recommended if it provides clear biological and economic benefits. Since rootstock performance is influenced by compatibility with the cultivar, the existing disease pressure, and climatic conditions, it is necessary to evaluate rootstocks with current cultivars to appraise possible benefits in a given area. Two experiments were carried out in two consecutive seasons with the objective of evaluating the benefits of grafting under Chilean conditions. The rootstocks used were ‘Marathon’ (Cucurbita maxima × Cucurbita moschata) and ‘Macis’ (Lagenaria siceraria) with different scions, including some seedless cultivars. In both experiments, grafted plants increased their yield compared with nongrafted plants (136% and 159% in Expts. 1 and 2, respectively). This effect was due to an increased number of fruit per plant (P < 0.01), and the weight gain of the fruit (P < 0.01). Plants presented with fusarium wilt [Fusarium oxysporum f. sp. niveum (FON)] in both experiments, which seemed to be the main limitation for nongrafted plant production. In the evaluation of quality attributes [soluble solid concentration (SCC), firmness, color, polar diameter, equatorial diameter, and rind thickness], positive effects were observed in the fruit of grafted plants. For the conditions of these experiments, the increase in yield of grafted plants would be associated with an economic benefit that exceeds its additional cost.
Transplant Fertilizer Solution and Early Season Plastic Mulch Increase Tomato Yield in Adequate Fertility Clay Loam Soil
Authors: Rohwer Charles L. , Fritz Vincent A.
Published: October 2019

It is commonly recommended to apply phosphorus- or nitrogen- and phosphorus-containing water-soluble fertilizers to annual vegetables at transplant to improve establishment and enhance yield. Plastic mulches are also recommended to increase soil temperature and enhance yield through similar root growth-promoting mechanisms early in the season. Our aim was to determine if the recommendations for transplant fertilizer solutions and plastic mulch are justified, and if the effects are interactive in a clay loam soil with moderate or high levels of existing phosphorus fertility and organic matter. We transplanted ‘Plum Dandy’ tomato (Solanum lycopersicum) in 2014 and 2015 into a field with high fertility using black polyethylene mulch or no mulch, and transplant solution containing water, 320 mg/plant nitrogen, or 320 mg/plant nitrogen + 475 mg/plant phosphorus. Mulch was removed 26 to 28 days after transplanting to eliminate midseason and late season mulch effects. We found yield-promoting and maturity-hastening effects in both years from transplant solutions containing both nitrogen and phosphorus (18% greater total ripe fruit weight than water control), and similar benefits of early season black plastic mulch (24% greater total ripe fruit weight than no mulch), indicating usefulness of either treatment in tomato production. We found no interactive effects of mulch and transplant solution.
Gardening Intervention for Physical and Psychological Health Benefits in Elderly Women at Community Centers
Authors: Park Sin-Ae , Lee A-Young , Son Ki-Cheol , Lee Wang-Lok , Kim Dae-Sik
Published: October 2019

The present study aimed to assess the physical and psychological health benefits of a 15-session gardening intervention in elderly women and to investigate satisfaction of the gardening intervention. Fifty elderly women (age >70 years) at two senior community centers located in Seoul, South Korea, were selected to participate in this study. Twenty-four elderly women at senior community center “A” participated in a twice-weekly gardening intervention (≈50 minutes per session) during the period Sept. to Nov. 2015; 26 elderly women at senior community center “B” comprised a control group. At the completion of the 15-session gardening intervention, physical health parameters such as body composition, physical functional ability, and hand function ability were assessed in both groups. Additionally, psychological health conditions, such as cognitive ability, depression, and sociality, were assessed. The elderly women also answered a questionnaire to assess the amount of physical activity experienced during daily life. Elderly women in the gardening intervention group exhibited significantly improved muscle mass, aerobic endurance, hand dexterity, cognitive ability, and decreased waist circumference (P < 0.05). In contrast, significantly decreased muscle mass and agility and increased depression were observed in the control group (P < 0.05). Moreover, elderly women in the gardening intervention group reported a significantly higher amount of daily physical activity compared with those in the control group (P < 0.05). Additionally, 95.8% of elderly women in the gardening intervention group reported of being very satisfied with the gardening intervention. In conclusion, the gardening intervention maintained and improved the physical and psychological health of elderly women at a senior community center, whereas elderly women in the control group experienced age-related reduced physical and psychological health conditions. More studies are needed to evaluate the effects of a gardening intervention in a larger population of elderly women; in addition, a longer intervention period would provide a better measure of health in elderly women.
Promising Olive Cultivars for Oil Production in Hawaii
Authors: Miyasaka Susan C. , Hamasaki Randall T.
Published: October 2019

To determine promising olive (Olea europaea) cultivars for oil production in Hawaii, seven trees each of 10 cultivars (Arbequina, Arbosana, Coratina, Frantoio, Koroneiki, Leccino, Mission, Moraiolo, Pendolino, and Taggiasca) were planted in Feb. and July 2011 at the Lalamilo Experiment station on Hawaii Island (lat. 20.0176°N, long. 155.6827°W, elevation 2700 ft). In addition, two trees each of these 10 cultivars were planted in June 2011, with the exception of Arbequina, which was planted in July 2012, at the Maui Agricultural Research Center in Kula, Maui (lat. 20.7564°N, long. 156.3289°W, elevation 3100 ft). At Lalamilo, after ≈2 years of growth in the field (2013), three cultivars of olives (Arbequina, Arbosana, and Koroneiki) flowered, fruited, and produced oil yields of greater than 20%. These same cultivars flowered and fruited in 2014 and 2015. There was no significant difference among cultivars in fresh weight fruit yield averaged over 2 years (2013 and 2014), ranging from 2.14 to 2.45 kg/tree. During December to March, calculation of chilling hours below 12.5 °C was 141 hours during 2012–13 and 161 hours during 2013–14. The other seven cultivars did not flower and fruit during these 2 years of growth at Lalamilo, perhaps due to a greater requirement for chilling hours. At Kula, after 3 years of growth (2015), nine cultivars of olives with the exception of Moraiolo flowered and fruited. Mean fresh weight fruit yield in 2015 ranged from 0.25 to 22.06 kg/tree for various cultivars grown in Kula, Maui. In 2013, the oil from three cultivars grown at Lalamilo was analyzed for free fatty acids (FFA), peroxide value (PV), ultraviolet absorption for conjugated double bonds, 1,2-diacylglycerol (DAG), and pyropheophytins (PPP). Oil quality was within the range of extra-virgin olive oil. There is a need to investigate further the effects of temperature and management on flowering and fruiting of olive cultivars grown in Hawaii at various elevations. In particular, ‘Arbequina’, ‘Arbosana’, and ‘Koroneiki’ appear to have a lower requirement for chilling hours than other cultivars tested.
Simplified Water Requirement Calculators for Fruits and Vegetables
Authors: Rowell Brent , Soe Mar Lar
Published: October 2019

New users of drip irrigation in Myanmar had no idea how much water to apply to their crops with drip and could not afford tensiometers or other soil moisture monitoring tools. The concept of a simple paper calculator was born out of their need for an easy-to-use yet inexpensive tool to estimate horticultural crop water requirements. We used a generalized crop coefficient and growth stage approach together with average evapotranspiration (ET) for the vegetable crops “Water Wheel” calculator and a canopy cover approach for the tree fruit calculator. Differences among published crop coefficients are relatively small for a large number of vegetables and single coefficients were used for groups of crops without putting farmers’ crops at risk. Vegetable crops were divided into two groups based on whether water requirements during harvest remained the same as for the flowering and fruiting stage or were reduced for the harvest period. A simplified canopy cover approach was used to determine water requirements for perennial fruit, tree, and vine crops. Our faith in the ability of farmers to make their own adjustments gave us confidence to simplify ET-based water requirements and make them available in the form of simple rotating disc calculators printed in color on laminated card stock. The calculators were welcomed by our staff and enabled them to provide reasonably reliable recommendations for new users of drip irrigation. When surveyed, field staff responded that 74% of farmers they advised followed Water Wheel recommendations. Rough estimates of fruit and vegetable water requirements reached a large number of new drip users in a form they could easily understand, thereby lowering adoption barriers for an unfamiliar technology. This paper describes the Water Wheel concept and design so nonspecialists might develop their own calculators using local climatic data.
Yield and Fruit Quality Traits of Atemoya Hybrids Grown in Puerto Rico
Authors: Goenaga Ricardo , Jenkins David
Published: October 2019

As consumers seek healthy and more diverse food products, the demand for tropical fruits has increased significantly during the last 15 years. There is a lack of formal experimentation to determine the yield performance and fruit quality traits of atemoya (Annona squamosa × A. cherimola) hybrids. Six atemoya hybrids (‘Bradley’, ‘Geffner’, ‘Priestly’, ‘Lisa’, ‘47-18’, and ‘75-9’) grown on an Oxisol soil were evaluated for 4 years at Isabela, PR. ‘Geffner’ and ‘Lisa’ had the highest number of marketable fruit averaging 8542 fruit/ha, and the highest yield of marketable fruit, averaging 1507 kg·ha−1; they did not differ from each other, but were greater than all other hybrids. Individual weight of marketable fruit was significantly higher in ‘75-9’ and ‘Priestly’ which averaged 264.8 g. Significantly higher soluble solids concentration values were obtained from fruit of ‘75-9’, ‘Bradley’, and ‘Geffner’ which averaged 23.8%; they did not differ from each other, but were greater than all other hybrids.
Structural Balance and Signed International Relations
Authors: Doreian Patrick , Mrvar Andrej
Published: October 2019

We use balance theoretic ideas to study the dynamics of the international system of nations in a network of signed relations from 1946 through 1999. Using the Correlates of War data for this period, we apply pre-specified signed blockmodeling to characterize the fundamental structure of this network. Even though the system expanded greatly with many ties being created and/or destroyed, the basic structure remained the same but with new positions being added over time. The blockmodels generated temporal measures of imbalance, as did the counts of imbalanced triples. Regardless of using the line index of imbalance or the number of imbalanced 3-cycles, the results provided decisive evidence contradicting the balance theoretic hypothesis of signed networks moving towards balanced states. Structural balance theory remains very useful by pointing to the more important study of how and why signed networks move towards and away from balance at different points over time. Some major methodological problems for studying signed networks, regardless of whether they involve nations or human actors, were raised and addressed. Proposals for future research are suggested for modeling and understanding the dynamics of signed networks.
Understanding the Influential People and Social Structures Shaping Compliance
Authors: Smith Rachel A. , Fink Edward L.
Published: October 2019

This study integrated efforts to identify influential people and to extend theories of structural predictors of compliance. Adults (N = 195) were shown a sociogram of 11 people who were connected by friendships. Participants were asked to imagine themselves in this group, identify a position for themselves, select another member for an interaction, and predict their likelihood of complying with the member’s request. Connectors (those wanting to link others) identified with more central positions for themselves and selected more central interaction partners. Agents with greater persuasive impact were more successful in gaining compliance from participants; for connectors, targets’ supportive impact also reduced their likelihood of compliance. Findings have implications for diffusion efforts that depend on interpersonal compliance, and for theories of social influence.
Using Lord of the Flies to Teach Social Networks
Authors: adams jimi
Published: October 2019

Lord of the Flies is commonly assigned reading for high school and college students. The novel about shipwrecked boys is often analyzed thematically to examine how the boys’ perceived isolation on the island effects their attitudes and behavior. However, what is similarly apparent is that the society they develop while on the island establishes certain patterns, and is governed by collective rules (some more explicit than others). Here I demonstrate how those behavioral patterns and norms are useful for interpreting the concepts and analytic tools found in social network literature. I describe how I used the novel as a “capstone” project in four sections of an undergraduate Social Networks course. This demonstrates how students’ readings of the text revealed several common families of social network measures leveraged in the book’s plot.

I would like to thank Ryan Light, David Schaefer and Skye Bender-deMoll for helpful comments in preparing this manuscript. Any errors that remain are my own.
U.S. and Whom? Structures and Communities of International Economic Research
Authors: Heiberger Raphael H. , Riebling Jan R.
Published: October 2019

Most studies concerned with empirical social networks are conducted on the level of individuals. The interaction of scientists is an especially popular research area, with the growing importance of international collaboration as a common sense result. To analyze patterns of cooperation across nations, this paper investigates the structure and evolution of cross-country co-authorships for the field of economics from 1985 to 2011. For a long time economic research has been strongly US centered, while influencing real-world politics all over the globe. We investigate the impact of the general trend of increasing international collaboration on the hegemonic structures in the “global department of economics.” A dynamic map of economic research is derived and reveals communities that are hierarchical and structured along the lines of external social forces, i.e. historical and political dimensions. Based on these findings, we discuss the influence of the core-periphery structure on the production of economic knowledge and the dissemination of new ideas.
A Family of Affiliation Indices for Two-Mode Networks*
Authors: Tutzauer Frank
Published: October 2019

An affiliation network consists of actors and events. Actors are affiliated with each other by virtue of the events they mutually attend. This article introduces a family of affiliation measures that captures the extent of actors’ affiliations in the network. At one extreme, one might have an actor who attended many events, but none of these events were attended by any of the other actors in the network. Although of high degree, in no reasonable interpretation would such an actor be considered highly affiliated with other actors in the network. At the other extreme, one might have an actor defined by a collection of events, all of which were attended by another actor(s), making the actor as enmeshed in the network as possible. Most actors will be between these extremes, with some events being shared by varying others, and some not. This article introduces a family of affiliation measures based on the entries of the co-occurrence matrix. After defining the measures, the cumulative distribution function of first-order affiliation is derived and expressed as a difference of binomials.
Influencia de fuentes de fosfato inorgánico en la expresión de proteínas de una cepa bacteriana solubilizadora de fosfato nativa de La Comarca Lagunera
Authors: Flores Castellanos Ana Sofía , Rodríguez Sifuentes Lucio , Pérez Gelvez Yeni Natalia Carolina , Gutiérrez Sánchez Gerardo
Published: October 2019

Introducción: El presente trabajo tuvo como objetivo identificar las proteínas implicadas en la solubilizacion de fosfatos inorgánicos (Pi) en Klebsiella aerogenes y evaluar la capacidad de solubilizacion de Pi bajo la influencia de fuentes de carbono (C) y nitrógeno (N) en bacterias aisladas de la Comarca Lagunera.Método: Se trabajó con ocho cepas bacterianas aisladas de cultivos forrajeros de La Comarca Lagunera y conservadas en glicerol a -20 °C. Se determinó el Índice de Solubilización (IS) en medio sólido Pikovskaya (PVK) y se cuantificó la solubilización de Pi en medio líquido con diferentes fuentes de C, N y fósforo (P). Se realizó una identificación molecular de la cepa que presentó la mayor capacidad para solubilizar el Pi. Para los estudios de expresión de proteínas, se realizaron cultivos bacterianos por duplicado con dos diferentes fuentes de Pi {(fosfato de calcio (FC) y fosfato de aluminio (FA)} en medio líquido PVK. Se llevó a cabo una precipitación de proteínas con ácido tricloroacético (TCA) y una cuantificación con BCATM Protein assay kit. Las proteínas se corrieron en gel de poliacrilamida al 12%, se realizó una digestión con la enzima tripsina y se analizaron los péptidos obtenidos por HPLC-espectrometría de masas. La identificación de la función de las proteínas se llevó a cabo mediante el uso de herramientas bioinformáticas.Resultados: K. aerogenes fue la bacteria que presentó una mayor capacidad para solubilizar FC (2.31 y 2.59) en medio sólido PVK Glucosa (G)-Urea (U) y G- Nitrato de Amonio (NA) respectivamente, FC (1.97 ppm) y FA (1.36 ppm) en medio líquido PVK U-G. En los cultivos bacterianos se identificaron doscientas dieciséis proteínas entre las cuales se encontraron: ABC transportadoras, histidina quinasa Pho, proteína del sistema de transporte específico de fosfato Pho U, involucradas con el aprovechamiento del P.Discusión o Conclusión: Las fuentes de C y N influyen en la capacidad de solubilización de Pi en bacterias nativas de La Comarca Lagunera. Los mejores resultados de solubilización se presentaron cuando la G se encontraba en el medio como fuente de C y la U como fuente de N. Bajo las condiciones de experimentación, no se observaron proteínas únicas de K. aerogenes para solubilizar el FC y FA. Se observó únicamente diferencias en el nivel de expresión de algunas proteínas identificadas.
Hemicellulose Removal in Curaua (Ananas erectifolius) Fibers for Polyester Composites
Authors: Rodrígues Beatriz S. , García Rafael M. , Leão Rosineide M. , Amico Sandro C. , Luz Sandra María
Published: October 2019

Introduction: Alkaline treatments extract hemicellulose from the fibers, which can be reused in the manufacture of other materials, and the cellulosic portion can be applied as reinforcement in a composite. This way, all components of the fibers are utilized.Method: In this work, curaua fibers (Ananas erectifolius) were treated with potassium hydroxide (KOH) to solubilize part of the hemicellulose and lignin, and the cellulose-rich fibers were used to manufacture composites with unsaturated polyester, which were characterized to investigate the effect of the treatment on their properties.Results: The alkaline treatment removed large portions of hemicellulose and significantly degraded the crystalline cellulose and lignin, resulting in a small increase (2.4%) in overall crystallinity and with a negative impact on their thermal stability. SEM images showed defibrillation of the treated fiber and fibril separation, increasing roughness and surface contact area.Conclusions: In all, although the alkaline treatment substantially modified the fibers and no significant changes were observed in the mechanical properties of the composite, the total removal of hemicellulose was found to affect the integrity of cellulose fibers making harder their application as reinforcement. However, the higher cellulose content could be useful for other applications.
Efecto de la adición de ácidos orgánicos sobre la bioacumulación de Plomo, Talio y Vanadio en Chrysopogon zizanioides creciendo sobre suelos contaminados de un relleno sanitario
Authors: De la Cruz López César Augusto , Ramos Arcos Sebastián Alberto , López Martínez Sugey
Published: October 2019

Introducción: La fitorremediación ofrece una alternativa para la remoción de contaminantes presentes en el suelo. Chrysopogon zizanioides (Vetiver) es una planta fitorremediadora que ha dado resultados favorables en la remoción de metales. Sin embargo, pequeñas cantidades de metales quedan retenidos en el suelo sin ser biodisponibles para la especie. La utilización de agentes quelantes como los ácidos orgánicos utilizados en este estudio, mejoran los procesos de fitorremediación haciendo biodisponibles los metales que han quedado retenidos en el suelo y las plantas. Por lo tanto, el objetivo de esta investigación fue evaluar el efecto de los ácidos orgánicos sobre la biodisponibilidad de Pb, Tl y V en C. zizanioides, en un suelo expuesto a los lixiviados de residuos sólidos urbanos del relleno sanitario de la empresa Promotora Ambiental S.A.B de C.V.Método: C. zizanioides se propagó a partir de esquejes que fueron aclimatados antes de ser colocados en las unidades experimentales las cuales contenían el suelo proveniente del relleno sanitario. Estos esquejes se expusieron 40 días a lixiviados, a los cuales se les añadieron soluciones de ácidos orgánicos (ácido cítrico y ácido tartárico en 10 mM y 15 mM). Se caracterizó el suelo, se midió pH y Materia Orgánica con base en la NOM-021-SEMARNAT-2000 y Aguilera y Domínguez (1982). El análisis de los metales presentes en las muestras de raíz, hojas y suelo se realizó por medio de espectrometría de Emisión Óptica por Plasma de Acoplamiento Inductivo (ICP-OES).Resultados: Se observó un incremento en el pH y materia orgánica del suelo en los tratamientos en que habían sido añadido soluciones de los ácidos orgánicos, el tratamiento con ácido cítrico 10 mM movilizó en el suelo la mayor cantidad de Plomo, Talio y Vanadio, de igual forma el T2 con ácido cítrico 10 mM logró que se acumulara la mayor cantidad de Plomo, Talio y Vanadio en Vetiver, logrando una mayor acumulación de Talio en las hojas de la planta.Discusión o Conclusión: La presencia de los ácidos orgánicos en el suelo donde crece Vetiver aumentó significativamente los valores del pH y materia orgánica, favoreciendo así la absorción de metales hacia la planta Vetiver. El T2 que corresponde al tratamiento con ácido cítrico 10 mM, fue el que obtuvo mayor efectividad durante la movilización de Plomo, Talio y Vanadio del suelo hacia la planta. Se identificó la presencia de Vanadio en el suelo y la planta. Es la primera vez que se documenta que Vetiver absorbe y acumula Vanadio en altas concentraciones en sus raíces, sugiriendo así un proceso de fitoestabilización exitoso en suelos contaminados por este elemento.
Radiographic characteristics in the periapical healing post endodontic treatment in patients of the Autonomous University of Yucatan, School of Dentistry
Authors: Jurado Patrón Oscar David , Vargas López Andrés , Vega Lizama Elma María , Alvarado Cárdenas Gabriel , López Villanueva María Eugenia , Ramírez Salomón Marco Antonio
Published: October 2019

Introduction: The radiographic control of the root canal treatment can evaluate the healing of the periapical lesions. The objective of this study was to determinate the characteristics of the radiographic healing that was observed after one year, during follow-up sessions; so, the healing of the lesions according to the periapical pathology at the beginning of the treatment and the causes of failure of the endodontic treatments were recorded.Method: This is a prospective, observational, descriptive and longitudinal study, carried out in patients who attended control one year after endodontic treatment through the Periapical Index (PAI).Results: A total of 395 teeth of patients who underwent endodontic treatment one year prior to data collection, 87 presented radiogaphically observable periapical lesions; of these, 40 (45.97%) attended the control at one year. The frequency of cases in which some degree of radiographic healing was observed one year after treatment was 97.46%. The pathology with more cases of complete healing was periodontitis with sinus tract. In general, 84.61% of the cases decreased two levels in their PAI after one year. The 100% of the cases of failure presented vertical root fractures.Conclusion: The frequency of periapical healing after endodontic treatment is high. The main cause for the failure of the treatments documented in this study was the lack of coronal restoration that caused vertical fractures.
Parámetros y tendencias genéticas de variables de crecimiento para bovinos Romosinuano en México
Authors: Ramírez Valverde Rodolfo , Martínez Rocha Ricardo E. , Núñez Domínguez Rafael , García Muñiz José Guadalupe
Published: October 2019

Introducción: Los bovinos Romosinuano son originarios de Colombia, pero en México hay ganaderos dedicados a su cría desde hace dos décadas. Su población en México es pequeña y no se encontraron estudios que documenten aspectos elementales para establecer un programa de mejoramiento genético en esta población. El objetivo de este estudio fue estimar los parámetros genéticos de pesos al nacimiento (PN) y al destete ajustado a 240 d (PD), así como documentar las tendencias genéticas para estas dos características en la población Romosinuano de México.Método: La base de datos provino de la “Asociación Mexicana de Criadores de Ganado Romosinuano y Criollo Lechero Tropical, A. C.”. La información utilizada incluyó 895 registros de PN y 517 de PD. El pedigrí incluyó 4,537 animales nacidos entre 1950 y 2016. Los análisis fueron realizados mediante el programa ASReml, preliminarmente usando modelos univariados para identificar los mejores, mediante la prueba de razón de verosimilitudes. El modelo animal bivariado para ambas características incluyó los efectos fijos de grupo contemporáneo (año-hato-época-sexo), la covariable edad de la madre al parto, lineal y cuadrática, y la covariable lineal de la proporción de genes Romosinuano. Los efectos aleatorios fueron los genéticos aditivos directos y la interacción semental por grupo contemporáneo para ambas características, más los genéticos aditivos maternos para PD. Las tendencias genéticas fueron estimadas mediante regresión lineal simple del promedio de los valores genéticos sobre el año de nacimiento de los animales.Resultados: Las estimaciones de heredabilidad para efectos directos fueron 0.19 ± 0.09 y 0.21 ± 0.12, para PN y PD. La heredabilidad materna para PD fue 0.04 ± 0.05. La proporción de la varianza fenotípica explicada por la interacción semental por grupo contemporáneo fueron 0.21 ± 0.05 y 0.11 ± 0.08 para PN y PD. La correlación genética entre PN y PD fue alta y positiva (0.69 ± 0.28). Las tendencias genéticas para PN y PD no fueron diferentes de cero (P > 0.05).Conclusión: Las estimaciones de heredabilidad para PN y PD reflejan variabilidad genética suficiente para implementar un programa de selección en estas características.