Deep Tap Research Articles

Revealing dynamic goals for university’s sustainable development with a coupling exploration of SDGs

The sustainability of universities is important to realize global SDGs. However, there is a lack of research on the internal dynamic relationship of the SDGs in universities. This study aims to deep tap the dynamic mechanism and scientific core connotation of the relationship among the environmental, economic, and social dimensions in the sustainable development of the top 100 universities ranked by the Times Higher Education Impact Rankings, in order to point out the specific action direction in line with their characteristics. This study adopts coupling model, Sustainable Development Triangle model, and Grey Relational Analysis to learn the development system and the main development dynamic goals of universities on five continents. The results show that the development of the top sustainable universities in the five continents is very uneven with three echelons of development in the world. Although the sustainability quality in the world has improved year by year, the sub-quality of sustainability of the top universities on each continent is obviously different. The sustainable coupling degrees of the top universities of the five continents are increasing, but the overall coupling strength is not high. The development of coupling is at the level of weak coordination. SDG12 is the main dynamic goal for the top universities in Asia and America, SDG6 is for Europe and Oceania, and SDG3 is for Africa.

Mutagenic-sensitivity and variability in the putative mutants of polyembryonic mango genotypes

Polyembryonic mango genotypes are considered the best resources for developing rootstocks owing tothe production of uniform, true-to-type nucellar seedlings with the deep tap root systems. However, their use inbreeding programmes is often limited by a narrow genetic base due to maternal inheritance. Hence, enhancementin or creation of variability for traits of interest becomes a pre-requisite, if rootstock breeding in mango has tobe undertaken. In this study, we attempted to induce variability in polyembryonic mango genotypes, Bappakkai,Nekkare and Kurukkan by treating their kernels with different doses of gamma rays ranging from 15 to 35 Gy.The results revealed delayed germination and a decrease in germination percentage with increasing dosageof gamma irradiation. The lethal dose (LD50) values for gamma radiation were determined, based on the seedgermination percentage using Probit analysis values, which were 22.39 Gy, 19.95 Gy, and 19.95 Gy for Bappakai,Nekkare and Kurukkan, respectively. Other traits like the number of seedlings emerging per kernel, plant height,inter-nodal length, and the number of leaves showed a gradual decrease in their mean values with increasingirradiation dosage. The results suggest the effectiveness of induced mutation in bringing about variability intraits like plant height for developing dwarf rootstocks to be used in high-density planting.

In Vitro Establishment, Hydroponic, Salt Tolerance, Antifungal And Phytochemical Investigations In Important Sand Binder Medicinal Plant Ipomoea Pes-Caprae

Ipomoea pes-caprae (L.)R. Br. (Beach Morning Glory) is a latex-producing creeper with long stems and deep tap roots characterized by its ability to tolerate salinity and salty air. It has environmental impact as a sand binder. This medicinal plant is known to be astringent, laxative, tonic, alternative, and diuretic in traditional medications. Present study deals with the optimizations of in vitro protocols to raise and multiply plant at different morphogenic levels. It was found that nodal explants were showing new bud generation on MS+ 3.0 mg/L BAP (6-Benzyl amino purine) with generation frequency of 90.00±2. The best rooting response was observed on MS+ 1.0 mg/L IBA (Indole-3-butyric acid) where maximum number of roots (8.0±1.0) were generated with 80% acclimatization rate in lab conditions. Moreover, salt tolerance studies were performed in hydroponic system. In comparison to liquid MS (Murashige and Skoog) basal media and distilled water, hydroponic system was found to be optimum in roots and shoot generation. Out of four concentrations (0.2- 0.8%) of sodium chloride (NaCl) used in present study, 0.4% NaCl salt concentration showed optimum growth of root and shoot simultaneously. In vitro established plants were subjected to FTIR (Fourier transform infrared spectroscopy) and GC-MS (Gas chromatography–mass spectrometry) analysis and were showing array of compounds. The methanolic extract of lab acclimatized plants showed modest antifungal activity against Pythium and Alternaria fungal genus with percent inhibition of 17.71 and 8.03, respectively on 6th day readings.

Breeding for resistance and integrated management of web blight in common bean

AbstractCommon bean (Phaseolus vulgaris L.) production in the humid tropics may increase if less predictable rainfall becomes a serious seed yield constraint in traditional areas of production. The successful production of common bean will require the effective management of common bean diseases favored by hot and humid conditions. Web blight (WB), caused by Thanatephorus cucumeris (Frank) Donk, is a serious disease of common bean in the humid tropics causing significant losses in both seed yield and seed quality. At present, only moderate levels of WB resistance have been identified. Leaf and seed damage and leaf lesion size are criteria that have been successfully used to screen common bean genotypes for WB resistance in the greenhouse and in the field. Pedigree selection has been successfully used to develop cultivars having moderate levels of resistance. Recurrent selection has been used to broaden the genetic base and to produce progeny having higher levels of WB resistance. Sources of resistance from secondary gene pools should be used to combine resistance genes from diverse sources. Common bean cultivars with earlier maturity, deep tap roots, and terminal drought tolerance may be desirable traits for farmers who plant later in the wet season to avoid WB. Seed production during the dry season using irrigation would help to reduce infection of the seed and transmission of the WB pathogen. Minimum tillage techniques are useful to help to reduce the spread of the disease. Biological control may contribute to the management of WB and complement genetic resistance.

Rooting in the Desert: A Developmental Overview on Desert Plants.

Plants, as sessile organisms, have evolved a remarkable developmental plasticity to cope with their changing environment. When growing in hostile desert conditions, plants have to grow and thrive in heat and drought. This review discusses how desert plants have adapted their root system architecture (RSA) to cope with scarce water availability and poor nutrient availability in the desert soil. First, we describe how some species can survive by developing deep tap roots to access the groundwater while others produce shallow roots to exploit the short rain seasons and unpredictable rainfalls. Then, we discuss how desert plants have evolved unique developmental programs like having determinate meristems in the case of cacti while forming a branched and compact root system that allows efficient water uptake during wet periods. The remote germination mechanism in date palms is another example of developmental adaptation to survive in the dry and hot desert surface. Date palms have also designed non-gravitropic secondary roots, termed pneumatophores, to maximize water and nutrient uptake. Next, we highlight the distinct anatomical features developed by desert species in response to drought like narrow vessels, high tissue suberization, and air spaces within the root cortex tissue. Finally, we discuss the beneficial impact of the microbiome in promoting root growth in desert conditions and how these characteristics can be exploited to engineer resilient crops with a greater ability to deal with salinity induced by irrigation and with the increasing drought caused by global warming.

Whole root system water conductance responds to both axial and radial traits and network topology over natural range of trait variation

Current theory and supporting research suggests that radial transport is the most limiting factor to root water uptake, raising the question whether only absorbing root length and radial conductivity matter to water uptake. Here, we extended the porous pipe analytical model of root water uptake to entire root networks in 3D and analysed the relative importance of axial and radial characteristics to total uptake over parameter ranges reported in the literature. We found that network conductance can be more sensitive to axial than radial conductance of absorbing roots. When axial transport limits uptake, more dichotomous topology, especially towards the base of the network, increases water uptake efficiency, while the effect of root length is reduced. Whole root system conductance was sensitive to radial transport and length in model lupin (Lupinus angustifolius L.), but to axial transport and topology in wheat (Triticum aestivum L.), suggesting the root habit niche space of monocots may be constrained by their loss of secondary growth. A deep tap root calibrated to oak (Quercus fusiformis J. Buchholz) hydraulic parameters required 15 times more xylem volume to transport comparable amounts of water once recalibrated to parameters from juniper (Juniperus ashei Small 1901), showing that anatomical constraints on axial conductance can lead to significant trade-offs in woody roots as well. Root system water uptake responds to axial transport and can be limited by it in a biologically meaningful way.

Leaf morphological and genetic variation between Quercus rubra and Quercus ellipsoidalis: comparison of sympatric and parapatric populations

Species boundaries in oaks are often not clear-cut, which is potentially a result of interspecific hybridization with trait introgression and phenotypic plasticity. Quercus rubra L. and Quercus ellipsoidalis E.J. Hill are two interfertile partially sympatric red oak species (section Lobatae) with different adaptations to drought. Quercus ellipsoidalis is the most drought tolerant of the North American red oak species and is characterized by deep tap roots, a shrubby growth and by deeply dissected leaves. Genetic differentiation between species is low for most molecular markers. However, one genic microsatellite in a CONSTANS-like (COL) gene, FIR013, was previously identified as outlier locus under strong divergent selection between species. In this study, we analyzed leaf morphometric traits in neighboring (parapatric) Q. rubra/Q. ellipsoidalis populations and in one sympatric population from the same region along an environmental gradient. Using multivariate statistics of leaf traits both species showed distinct bimodal frequency distributions for the first canonical discriminant function with some overlap in the phenotypic extremes, especially in the sympatric population. Leaf dissection traits showed strong and consistent differentiation between species in sympatric and parapatric populations, while differentiation for leaf size was lower in the sympatric population under more similar environmental conditions. Leaf phenotypes in F1 hybrids and introgressive forms suggested maternal effects and introgression of leaf traits between species. The association of outlier gene copy number at FIR013 with species-discriminating leaf traits in Quercus rubra can be a reflection of population differences since outlier gene copy number and population membership show significant collinearity. Similar environmental selection pressures on outlier alleles and leaf shape could also have resulted in this association. In future studies, segregating full-sib families could be used to test whether outlier alleles and associated genomic regions are indeed associated with leaf traits or other species-discriminating characters.

Assessing water use by Prosopis invasions and Vachellia karroo trees: Implications for groundwater recovery following alien plant removal in an arid catchment in South Africa

Prosopis spp., (or Mesquite), is a desert adapted woody weed which has invaded large parts of arid and semi-arid regions. It has a characteristic deep tap root, and forms dense impenetrable thickets along river banks, flood plains, and seasonal water courses. Several studies have quantified the water use by Prosopis, but there is limited information on how this compares with that of co-occurring groundwater dependent indigenous tree species in the arid and semi-arid tropics. Consequently the effects of removing Prosopis on groundwater, where they co-occur with indigenous trees, are not known. This study quantified the incremental water use by Prosopis invasions compared with the indigenous deep rooted Vachellia karroo (V. karroo) trees that normally replace Prosopis once it has been cleared. The study was done in an arid catchment in the Northern Cape Province of South Africa. Stem sap flow dynamics, groundwater levels, and weather data were collected hourly over 15months in the invaded catchment. Data collection continued for a further 11months after Prosopis had been cleared to monitor the recovery of the ecosystem from the invasions. There was no significant difference (P=0.116) in the sap flux density of the two species although Prosopis had a much thinner sapwood depth than V. karroo due to its ring porous wood anatomy. However, at the stand scale Prosopis transpired more than five times more water (∼544mmy−1) than V. karroo (∼91mmy−1) since there were six times more Prosopis than the indigenous species. The removal of Prosopis slowed down the rate of decline of the water table from a pre-clearing peak of ∼8.9–5.0mmd−1 after alien plant removal. Tree transpiration was accurately predicted by a simple model that used aquifer properties and hourly changes in water table depths with a RMSE of ±0.22mmd−1 before and ±0.32mmd−1 after clearing Prosopis.

Propagation of positive streamers on the surface of shallow as well as deep tap water in wide and narrow dielectric channels

The results of experiments studying long-living positive streamers propagating on the surface of tap water are presented; the plasma-forming gas is air at atmospheric pressure. Measurement data for the strength of the longitudinal electric field in the surface streamer, the streamer velocity versus time until it stops, and the length of the streamer versus the applied voltage are presented. It is revealed that the depth of the water in a basin influences the streamer length: the deeper the water, the longer the streamer. Besides this, restricting the transverse direction of the area in the water accessible for streamer extension suppresses streamer branching until it fully disappears. It is shown that non-branching streamers propagating in narrow water channels increase their length considerably. Placing a dielectric plate with long, narrow slits of the required configuration on the water enables one to control the trajectory of streamer propagation. Three-dimensional numerical calculations of the spatial structure of the electric field and the current inside and outside the streamer in the water basin with different depths and widths were made. It is shown numerically that the streamer length and its diameter strongly influence both the strength and spatial structure of the electric field in the air around the streamer.

Monitoring of Stem Water Content of Native and Invasive Trees in Arid Environments Using GS3 Soil Moisture Sensors

Core Ideas Stem water content of trees was successfully monitored using GS3 capacitance sensors. Temperature calibration was essential for correct interpretation of monitoring data. The monitoring clarified water use characteristics of the trees in arid environments. Dielectric soil moisture sensors have the potential for nondestructive and real‐time monitoring of the stem water content (θst) of living trees. This study was conducted to investigate the water use characteristics of trees in drylands through monitoring of θst using newly developed capacitance sensors (GS3). The plants used for data collection were Prosopis juliflora (Sw.) DC. (mesquite, invasive) in Sudan and Tamarix ramosissima Ledeb. (tamarisk, invasive) and Prosopis pubescens Benth.(screwbean mesquite, native) in the United States. The GS3 probes were installed into the trunks of two trees for each species. Stem‐specific calibration equations and temperature calibration equations were derived through laboratory experiments and analysis of field observation data. The temperature calibration equations reduced inappropriate variations of θst caused by daily fluctuations in stem temperature, suggesting that these are essential for correct interpretation of monitoring data of θst in arid environments. The θst of the mesquite trees in Sudan clearly increased after heavy rainfall events and started decreasing when the soil water content became close to the wilting point. These findings indicate that mesquite trees use soil water in rainy seasons, even though they are generally considered to use groundwater through deep tap roots. The θst of neither species in the United States responded clearly to rainfall events, indicating that they depend on shallow saline groundwater. The θst of the tamarisk decreased monotonically throughout the monitoring period, apparently in response to feeding damage caused by the tamarisk leaf beetle (Diohabda sp.), which had been released for biological control of tamarisk.

The production and water extraction of lucerne and ryegrass under different irrigation frequencies on a shallow soil.

Abstract A field experiment was conducted on a shallow soil (low plant available water holding capacity) at Lincoln (Canterbury, New Zealand) to compare the biomass production of lucerne (Medicago sativa L.) and perennial ryegrass (Lolium perenne) under four different irrigation frequencies: (T1) replacing water use (WU) twice a week (replicating centre pivot rewetting frequencies); (T2) replacing WU fortnightly (replicating travelling irrigator); (T3) replacing WU every 3 weeks (replicating border dyke); (T4) nil irrigation (rain fed only). Soil water content was measured hourly at 0-30 cm depth and fortnightly at 0-150 cm depth. Plots were sown in March 2011 and defoliated on eight (ryegrass) and five to six (lucerne) occasions each season between September 2011 and May 2014. Annual biomass production during the first year was highest for ryegrass under each treatment because the lucerne crops were still establishing. During the second and third year of experimentation ryegrass yielded higher or similar to lucerne under the irrigated treatments (T1, T2 and T3). This was attributed to a decline in lucerne stands due to weed pressure. It is important to note that the ryegrass crop has received 250-700 kg N/ha per year depending on the irrigation treatment. Under dry conditions (T4) ryegrass yielded more than lucerne in both year 2 and 3. This result contrasts the literature and is attributed to the greater capacity of ryegrass to grow in cooler season and the stony sub-soil meaning lucerne received no summer yield advantage from its deep tap root. Key words: Medicago sativa L., Lolium perenne, biomass, water extraction, irrigation frequency

Measurements and weather observations at persistent deep slab avalanches

Persistent deep slab avalanches are generally hard to forecast and can release under diverse conditions ranging from storms to clear days to locally induced stress on the snowpack. For the formation of many natural avalanches, a point is reached where the mass loading of overlying snow exceeds the mechanical properties of the weak layer. This can occur from additional loading above the weak layer, such as from precipitation or wind loading. Furthermore, natural failure can occur from solar warming and temperature variations. External stresses applied to the snowpack from skiers, snowmobilers, and other forces can also trigger deep slab avalanches. We accessed and made field measurements at 41 persistent deep slab avalanches that released after the avalanche cycle of the respective persistent weak layer. These measurements included the properties of the failure layers, slab load, and preceding weather to determine trends and correlations between such variables. The failure planes were analyzed using the Deep Tap test (DT), Propagation Saw Test (PST), shear frame tests, and hand hardness. The overlying loads were calculated using density measurements. Spatial variability across the crowns was also assessed by the use of multiple profiles and tests. Precipitation, temperature, and wind data were obtained from the nearest automatic weather station to the respective avalanche start zone. DTs often yielded sudden (Q1) fractures and the cut length in PSTs was usually less than 60% of the column length when the fracture propagated to the end. Tests were repeated at multiple sites for a few deep slab avalanches and they indicated that DT taps and shear strength of the failure layer tended to increase with crown height. Crown height typically varied substantially at each deep slab avalanche. Preceding weather prior to the accessed deep slab avalanches showed an increase in precipitation and change in temperature for some releases and little change in wind speed and direction for many releases.

Effect of Induced Soil Compaction on Changes in Soil Properties and Wheat Productivity under Sandy Loam and Sandy Clay Loam Soils: A Greenhouse Experiment

The continuous use of heavy machinery and vehicular traffic on agricultural land led to an increase in soil compaction, which reduces crop yield and deteriorates the physical conditions of the soil. A pot experiment was conducted under greenhouse conditions to study the effects of induced soil compaction on growth and yield of two wheat (Triticum aestivum) varieties grown under two different soil textures, sandy loam and sandy clay loam. Three compaction levels [C0, C1, and C2 (0, 10 and 20 beatings)], two textural classes (sandy loam and sandy clay loam), and two genotypes of wheat were selected for the experiment. Results indicated that induced soil compaction adversely affected the bulk density (BD) and total porosity of soil in both sandy loam and sandy clay loam soils. Compaction progressively increased soil BD from 1.19 Mg m−3 in the control to 1.27 Mg m−3 in C1 and 1.40 Mg m−3 in C2 in sandy loam soil while the corresponding increase in BD in sandy clay loam was 1.56 Mg m−3 in C1 and 1.73 Mg m−3 in C2 compared to 1.24 Mg m−3 in the control. On the other hand, compaction tended to decrease total porosity of soil. In case of sandy loam, porosity declined by 5% and 17% in C1 and C2, respectively, and declined in sandy clay loam by 29% and 54%, respectively. Averaged over genotypes and textures, shoot length decreased by 15% and 26% at C1 and C2, respectively, and straw yield decreased by 21% and 61%, respectively. The compaction levels C1 and C2 significantly decreased grain yield by 12% and 41%, respectively, over the control. The deleterious effect of compaction was more pronounced on root elongation and root mass, and compaction levels C1 and C2 decreased root length by 47% and 95% and root mass by 41% and 114%, respectively, over the control. Response of soil texture to compaction was significant for almost all the parameters, and the detrimental effects of soil compaction were greater in sandy clay loam compared to sandy loam soil. The results from the experiment revealed that soil compaction adversely affected soil physical conditions, thereby restricting the root growth, which in turn may affect the whole plant growth and grain yield. Therefore, appropriate measures to avoid damaging effects of compaction on soil physical conditions should be practiced. These measures may include soil management by periodic chiseling, controlled traffic, conservation tillage, addition of organic manures, and incorporating crops with deep tap root systems in a rotation cycle.

Propagation by stem cuttings and root system structure of Jatropha curcas

Scarce knowledge about the propagation of Jatropha curcas is one of the limitations for the growth of cultivated area with this oilseed crop. The effect of stem cuttings length, basal area, and position on the branch on sprouting and early growth of jatropha plants were evaluated, and the effect of the propagation method on the structure of root system of adult plants was studied. The growth and development of Jatropha curcas plants were influenced by length and basal area of stem cuttings. Short cuttings favor early sprouting, but long and thick cuttings promote more shoot and root growth. Plants originated from stem cuttings obtained from the base of the branch grew more shoot structures (buds, stems, and leaves) than stem cutting from middle and apex of the branch. Leaf area at 75 days after planting was not influenced by the dimensions of stem cutting. The most vigorous root system was observed in the plants that originate from direct seeding, without any transplanting. Propagation using bag or root plug interferes with the formation of a deep tap root. Propagation through stem cuttings resulted in a very different root system structure, with predominance of superficial and thin roots. When the cap of a tap root is lost, the plant was able to regenerate a new root.

Evaluation of forage legumes for introduction into natural pastures of semi‐arid rangelands of Kenya

AbstractTo address the potential of legumes to contribute to improved quality and quantity of natural pastures in the semi‐arid rangelands of Kenya, five legume species were introduced and evaluated in a small‐plot field experiment over three growing seasons. The investigated species were glycine (Neonotonia wightii), siratro (Macroptilium atropurpureum), dolichos (Lablab purpureus cv. Rongai), velvet bean (Mucuna pruriens) and shrubby stylo (Stylosanthes scabra cv. seca). Treatments included two cutting heights (ground level and 15 cm) and two cutting intervals (at 2 and 4 months). The mean dry matter (DM) yields of glycine and siratro were highest when the legumes were harvested at ground level at 2‐month intervals (10·31 and 7·81 t ha−1 year−1 respectively). Mean DM yield of stylo was highest when the legume was harvested at 15 cm after 4 months (3·52 t ha−1 year−1). These three legumes also produced high organic matter through litter fall, which contributed to soil fertility. Evidence from a supporting pot experiment showed effective nodulation and potential for N fixation. These legumes also possessed deep tap roots and withstood heavy defoliation. These three legumes were selected for further integration with grasses in natural pastures. The DM yields of dolichos and velvet bean when harvested at 15 cm after 2 or 4 months were low (2·48 and 1·91 t ha−1 year−1), and these species were considered inappropriate for further investigation.

Stochastic soil water dynamics of phreatophyte vegetation with dimorphic root systems

As the direct uptake of deep groundwater by vegetation may be essential in semiarid regions, we incorporated this process in stochastic root zone water balance models. The direct water uptake by vegetation via deep tap roots is simulated using one additional empirical parameter. This is considered for the case of feedback with root zone saturation and without such feedback. The model that accounts for feedback between shallow root zone saturation and groundwater uptake by deep roots takes up less water if the shallow root zone is wet. The behavior of the models demonstrates that for certain combinations of climate and groundwater depths this feedback becomes important in determining differences in total evapotranspiration (ET). This feedback mechanism also captures hydraulic redistribution processes. The range of relative contributions of groundwater to ET predicted by the models was similar to values derived in isotope studies.

Root suckering patterns in Populus euphratica (Euphrates poplar, Salicaceae)

To understand the spatial structure of monospecific Tugai forests (Xinjiang Province, China) growing as gallery woods nourished by ground water, root suckering in Populus euphratica was studied by a combination of morphological and molecular analyses. Seedlings grow a deep tap root and keep this as adult trees, whereas root suckers never develop a tap root but utilize the horizontally stretching root of their parent trees. The resulting reverse “T” root architecture distinguishes reliably even adult root suckers from generatively grown trees. Due to assimilate input from the root sucker, the distal root (pointing away from the parent tree) becomes thicker soon than its proximal root, which allows determination of the direction of vegetative growth. One stand including 279 young trees germinated from seeds and 267 root suckers was mapped completely, and selected suckers were assigned to parent trees by genotyping with microsatellite DNA. Root suckers develop up to 40 m away from parent trees on horizontal “spacer” roots, usually originating not deeper than 20 cm below surface. Trees begin with root suckering between 10 and 15 years, shortly before reaching flowering age. Cutting experiments indicated reduced survival of young root suckers disconnected from the parent tree. Without a tap root and with a rooting point close to the surface, declining ground water levels should lower the fitness of root suckers even more than that of generatively grown trees.

체조 철봉 콜만 기술동작의 훈련프로그램 적용 및 향상도평가

본 연구는 체조 철봉종목의 국가대표선수 2명을 대상으로 고난도 공중 비행 기술인 콜만 동작의 완성도를 높이기 위한 기술훈련 프로그램을 개발하여 8주간 적용하고 향상도를 3차원 영상분석을 통해 제시함으로써 경기력 향상에 도움을 주고자 하였다. 훈련 프로그램은 휘돌기 손 놓기, twist, 봉잡기로 구성하여 실시하였으며, 그 결과 다음과 같은 결론을 얻었다. 동작이 처음 시작되는 크게 휘돌기의 물구나무 경과 시 신체를 지면과 수직에 가깝도록 치켜세운 다음 수직하강에 가깝게 신체를 다운시켜서 깊은 추기기 운동을 수행케 하고, 고관절과 견관절의 굴신 폭을 크게 하는 추기기보다는 우선적으로 동체 회전을 중시하면서 신체중심을 충분히 끌어 올리는 봉 이탈, 그리고 비행 시 신체 각 관절의 상대각을 작게 하도록 주문하여 연습케 하였다. 그 결과 철봉의 탄성을 크게 유발하구 신체의 후방 진행속도를 증가시켜서 휘돌기의 구심력을 증가시키면서 높은 위치에서 봉을 이탈하였으며, 비행 시 신체를 빠르게 지면과 수직이 되도록 세울 수 있게 되어 여유로운 공중회전과 비틀기 운동을 수행할 수 있었다. 또한 상승할 때 손 놓는 타이밍을 맞추는데 특별히 신경 쓰지 않더라도 비행방향의 조절을 용이하게 할 수 있어서 봉잡기 시 철봉과 적정한 거리를 유지함과 동시에 충분한 동체의 회전과 비틀기 거리를 확보할 수 있었다. This study develops a technique training program to enhance the completion of Kolman, the high air flight technique, and applies it to two national athletes of the horizontal bar, one of the gymnastic events, for eight weeks. After that, their improvement was measured through 3D motion analysis to help them elevate their performance. The training program includes swing, hand release, twist, and bar hold, and its implementation produced the results stated below. They were made to practice the motion in the following way. After the hand-standing of giant swing which initiates the motion, they lift their body upward a little bit more. Next, they take their body down almost like a vertical descent and make a deep tap swing. Instead of doing the tap swing which widens the flection of hip and shoulder joints, while body revolution is more emphasized in particular, they release the bar as raising the centroid of their body sufficiently. During the flight, they try to narrow every joint in their body. As a result, the bar's elasticity becomes greatly increased, and since the backing rate of their body gets higher, the centripetal force of the swing is improved that they can release the bar in the higher position. In addition, because they can erect their body faster during the flight, they can perform comfortable twist and revolution in the air. They can also adjust the direction of the flight easily without too much concern for the proper timing of hand release as they rise. Thereby, they can not only maintain adequate distance from the bar for the bar hold but also ensure enough distance for body revolution and twist.

The Biology and Ecology of Feral Alfalfa (Medicago sativa L.) and Its Implications for Novel Trait Confinement in North America

Alfalfa (Medicago sativa) is an important forage crop worldwide. Apart from cultivated fields, alfalfa is also found along roadsides and in natural and semi-natural habitats. However, little information is available on the establishment capabilities of alfalfa in noncultivated areas and the potential of these founding populations to become feral. Some crop species have not lost all their wild characteristics during the domestication process and with several inherent traits favoring weediness, alfalfa could be one among those that can become feral. There is great interest in the feral potential of alfalfa, particularly due to the concerns that feral plants could act as genetic bridges and facilitate novel trait movement at the landscape level. Alfalfa is the first perennial, insect-pollinated crop to be genetically engineered and approved for unconfined release into the environment. This review investigates and compiles information in the literature that reveals the life history components that can influence ferality in alfalfa. Characteristics that can contribute to ferality in alfalfa include high genetic diversity, perenniality, quick regrowth potential, persistence, symbiotic nitrogen fixation, deep tap root system, drought and cold tolerance, and seed dormancy. With these traits, alfalfa is equipped to invade and dominate unmanaged habitats. Feral alfalfa populations can and will act as bridges for long-distance gene flow and facilitate the adventitious presence of novel traits in the environment. As such, feral populations will become a potential barrier for achieving coexistence of transgenic and nontransgenic alfalfa fields. Implications of ferality, including gene flow and hybridization with compatible wild relatives are also discussed in detail. This review serves as a resource for environmental risk assessment for the release of alfalfa containing novel traits.

American Beech

American Beech Gibson Fay-LeBlanc (bio) American Beech Pimp-Daddy, Blow Me, and D-Z 4-ever are the only legible phrases. Other cut-marks on the squat trunk are hieroglyphs: dark bands of hearts, snowflakes, arrow tips. To be pocked like this. To stand in a corner with shallow roots, one deep tap: to take the terror-etchings, the fleeting love-wounds onto skin and hold them out for someone to see the blurred, healing edges and faint unknowable letters. Despite the knife, despite withering, to push an annual dying further, faster, and let anyone anyone find this bark record of ache. [End Page 92] Gibson Fay-LeBlanc Gibson Fay-LeBlanc’s work appears in the AGNI Online, the New Republic, Pleiades, and Poetry Northwest, among other publications. He is currently the executive director of The Telling Room, a nonprofit community writing center in Portland, Maine. Copyright © 2007 University of Nebraska Press