Narrow Plots Research Articles

Bionic 3D Path Planning for Plant Protection UAVs Based on Swarm Intelligence Algorithms and Krill Swarm Behavior.

The protection of plants in mountainous and hilly areas differs from that in plain areas due to the complex terrain, which divides the work plot into many narrow plots. When designing the path planning method for plant protection UAVs, it is important to consider the generality in different working environments. To address issues such as poor path optimization, long operation time, and excessive iterations required by traditional swarm intelligence algorithms, this paper proposes a bionic three-dimensional path planning algorithm for plant protection UAVs. This algorithm aims to plan safe and optimal flight paths between work plots obstructed by multiple obstacle areas. Inspired by krill group behavior and based on group intelligence algorithm theory, the bionic three-dimensional path planning algorithm consists of three states: "foraging behavior", "avoiding enemy behavior", and "cruising behavior". The current position information of the UAV in the working environment is used to switch between these states, and the optimal path is found after several iterations, which realizes the adaptive global and local convergence of the track planning, and improves the convergence speed and accuracy of the algorithm. The optimal flight path is obtained by smoothing using a third-order B-spline curve. Three sets of comparative simulation experiments are designed to verify the performance of this proposed algorithm. The results show that the bionic swarm intelligence algorithm based on krill swarm behavior reduces the path length by 1.1~17.5%, the operation time by 27.56~75.15%, the path energy consumption by 13.91~27.35%, and the number of iterations by 46~75% compared with the existing algorithms. The proposed algorithm can shorten the distance of the planned path more effectively, improve the real-time performance, and reduce the energy consumption.

Modifikasi Lahan Pekarangan Non Produktif Menjadi Sumber Ketahanan Pangan Dan Ekonomi Keluarga

Currently the use of yards is an alternative for the community to meet the needs of the family. Because the yard has the potential to provide food for the family, the narrow plot of land can be modified into a yard that produces usability such as growing vegetables, empon-empon and fruits. Modification of narrow land can use several planting techniques, namely plants using pots (polybags) and hydroponics. The activity was carried out at the Pematang Indah Estate Housing Complex, Pematang Village, the Governor of Muara Bangkahulu District, Bengkulu City. The method of this activity is carried out by way of socialization through lectures and question and answer discussions with housewives who are formed in arisan groups. It is hoped that with this socialization there will be a maximum change in the function of the yard, the community already understands the importance of diversifying food and the health of the food consumed, and understands the management of family income by selling vegetable crops.

PENERAPAN TEKNOLOGI BERDASARKAN LUAS LAHAN DAN PENGARUHNYA TERHADAP PRODUKTIVITAS, DAN EFISIENSI USAHATANI KENTANG (Solanum tuberosum, L) (Suatu Kasus Pada Petani Kentang di Kecamatan Cipanas, Kabupaten Cianjur, Jawa Barat)

This study was to determine the effect of land area on the application of productivity technology and efficiency of granola potato farming. The unit of analysis is farmers who plant granola potatoes in MT 2021 in Cipanas District, Cianjur Regency, West Java. Respondents were taken from sample farmers with a layered random technique comparable to the size of 55 people. The analysis technique and hypothesis testing used were Kruskal Wallis and Cgi Square analysis. The results showed that potato farming performance based on land area: wide (1.75 ha), moderate (0.65 ha); and narrow (0.36 ha) shows relatively diverse conditions. The productivity of each farm land reached 13.56 tons/ha; 11.25 tons/ha; and 11.05 tons/ha. The income achievement of potato farming is Rp. 61,564,317/ha, medium land is Rp. 38.986.882/ha, and narrow land is Rp. 38.196.880/ha. R/C farming efficiency respectively: 2.34; 1.87 and 1.79. There are differences in the application of technology in potato farming based on large, medium, and narrow land areas. Potato farmers with large plots showed a better level of technology application than potato farmers with medium or narrow plots. The level of achievement of the application of potato farming technology was obtained by farmers with an area of 83.99% very good criteria; medium land farmers 72.50% good criteria; and farmers with narrow land 71.73 good criteria. There is a positive effect of the application of technology on the achievement of potato farming productivity. The productivity of large land farming shows a higher level than potato farmers with medium or narrow land. Each obtained by farmers with an area of 13,560 kg/ha; medium land farmers 11,185 kg/ha; and small land farmers 11,021 kg/ha. There is a positive effect of the application of technology on the efficiency of potato farming. Farming efficiency of farmers with large land shows a higher level than farmers with medium or narrow land. Each obtained by farmers with an area of 2.34; medium land farmers 1.87; and farmers with narrow land 1.79.

Cultivation of Family Medicinal Plants using the Verticulture Method as Efforts to Use Narrow Yard Land in Rawamangun, East Jakarta

The area of RW 01 Rawamangun, Pulogadung District, East Jakarta does not have an allocation of open land, so there is a minimum of green yards. The technology introduced in this community service activity is the cultivation of family medicinal plants in yards using the verticulture method. The purpose of this community service activity is to convey information about the cultivation of family medicinal plants through lectures, discussions, and direct practice of cultivating family medicinal plants in yards using the verticulture method. Evaluation of participants' knowledge improvement was carried out by pre- and post test after counseling and cultivation practices. Skills participants are carried out when evaluating the practice of cultivating medicinal plants in their yards. The results of the activity showed an increase in basic knowledge regarding the types, benefits, and techniques of cultivating family medicinal plants from technology. Family medicinal plant service activity is classified as successful and beneficial, due to increased knowledge more than 60 in average test scoring. The skills evaluation showed that some residents were able to plant and maintain family medicinal plants on a narrow plot of land using the proper verticulture method. The results of the cultivation of these medicinal plants, apart from being one of the real actions of plant greening, can also be in the form of powder products which can then be consumed as a body health measure or sold.

New Researches on the Late Antique History of Warfare. Review of the book: Меkhаmаdiev, Е. А. (2019). Voennaia organizatsiia pozdnei Rimskoi imperii v 253–353 gg.: epokha Konstantina I Velikogo i ego dinastii (306–353) [Military Organization of the Late Roman Empire in 253–353 AD: The Age of Constantine I the Great and His Dynasty (306–353)]. St Petersburg: Peterburgskoe Vostokovedenie. 424 p.

This paper states that E. A. Mekhamadiev’s book is a fundamental study on the military organization of the Late Rome Empire and Early Byzantium, with particular emphasis on epigraphy and papyrology. The use of the said data allowed the author to reconstruct the history of individual military units, their territorial movements, participation in various military campaigns, and changes of their ranks. Chronologically, the book studies the Late Roman Period from 253 to 305 AD. The researcher has examined the internal (organizational) structure of all regional armies in the age of Emperor Constantine I the Great (306–337) and his sons, not restricting himself to the study of individual and narrow plots related to the history of a particular province. He has analyzed the data relating to both the eastern and western regions of the Empire, uncovered their close relations, and revealed the permanent movements of the military units from the west to the east and in the opposite direction, depending on the geopolitical and domestic political situation.

Optimisation of building and road network densities in terms of variation in plot sizes and shapes

Urban form at the district scale is defined as a unique combination of the following basic spatial objects: road networks, plot patterns and building configurations. In particular, a plot represents one of the most important basic spatial objects of urban form. In recent theoretical and empirical work from downtown districts in Tokyo, it was found that (1) plot sizes and frontages approximately follow a log-normal distribution and (2) the parameters can be primarily estimated by building density (the number of buildings per unit area) and road network density (total length of road networks per unit area). High demand for housing and commerce in a district requires as many buildings and their plots as possible. However, this may generate many small and narrow plots, which makes the residential environment worse in terms of ventilation, sunlight and accessibility to a road. Hence, the ratio of the number of plots that cannot satisfy minimum criteria regarding their sizes and frontages should be as small as possible, taking into consideration the variation in plot sizes and frontages. Therefore, the rationale for the building and road network densities presented here will be discussed by considering the variation in plot sizes and frontages through a stochastic approach. Allowing for plot sizes that are smaller than the minimum plot size regulation as well as for plot frontages that are narrower than the minimum plot frontage regulation (these minimum criteria being determined by Japanese building codes), the maximum building density and optimal road network density will be obtained. These findings are expected to provide urban planners with a theoretical basis to discuss the validity of these two density values (based on the deterministic approach that assumes uniform urban form) in terms of evaluating the policy effect, such as minimum plot size and frontage regulation.

Postantique Soils as a Source of Land Use Information: A Case Study of an Ancient Greek Agricultural Area on the Northern Black Sea Coast

As an effect of intensive agricultural development of the steppes of the northern Black Sea coast, the finds of postantique agricultural landscapes that preserve relic elements of ancient land-use infrastructure are extremely rare. To these belongs the uniquely preserved ancient Greek land division system on the Tarkhankut Peninsula (north-western Crimea), which was studied using the methods of soil science and biomorphic analysis. This paper explores ancient land-use practices in order to reconstruct the original parameters of the land division system, as well as agricultural techniques employed. For postantique agricultural landscapes, an integrated geoarchaeological approach that includes GIS and remote sensing methodologies, in-field study of microrelief and soil registrograms, pedochronological dating technique, and physicochemical, geochemical, and biomorphic soil analyses has been developed and tested. The soil-geomorphological reconstruction shows that the Hellenistic land division system included a 4.5–4.9 m wide strip of land bordered by a 4.1–4.7 m wide (at the base) and c. 0.2 m high wall and a c. 2 m wide and over 15 cm deep trench, which controlled surface runoff and erosion. Ancient agricultural practices of slope farming resembled the modern ones. Surface runoff and soil erosion were controlled by dividing the catchment area into narrow plots, the borders of which on arable land were marked by simple earthen structures (low walls with shallow trenches). The biomorphic analysis of soil sampled atop these structures indicates that in ancient times, these earthen walls were not cultivated. The study of conservative properties preserved in pedomemory of postagrogenic soils provided valuable evidence of agricultural techniques used in the palaeogeographic conditions of the 4th and 3rd centuries BC.

RECENT BUILDING SYSTEM OF PENCIL HOUSES IN HANOI, VIETNAM

In this study, we focus on the building system of “Pencil houses” in Hanoi, Vietnam. Pencil houses are conventional houses: about five story reinforced concrete structure in urban narrow plot. Building pencil houses, households order a small worker team to build structural parts of pencil houses. These team, by themselves, can build large parts of houses including foundation, concrete forms, steel bars, casting concrete, laying brick walls, and plasters. We interviewed with ten these teams, two small construction companies, among others in Hanoi, and make clear the pencil house construction process, contracts system, and workers condition.

Optimum size and shape of plots based on data from a uniformity trial on Indian Mustard in Haryana

The most obvious use of uniformity trial data is to provide information on the most suitable size and shape of plots, in which the field was planted to a single variety and harvested as small plots. Indian mustard (Brassica juncea L.) cultivar RH-749 was grown using uniform crop improvement practices during rabi season of 2013-14 at Research Farm of Oilseed section, Department of Genetics and Plant Breeding, CCSHAU, Hisar, Haryana state, India, to estimate optimum plot size and shape using yield data of the 48 m × 48 m (2304 basic units) recorded separately from each basic unit of 1 m × 1 m. The variability among plots of different sizes and shapes was determined by calculating coefficient of variation. It was observed that the coefficient of variation decreases as the plot size increases in case of both the directions i.e., when plots were elongated in N-S direction (88 per cent decrease) or elongated in E-W direction (93 per cent decrease). Further it was observed that long and narrow plots elongated in E-W direction were more useful than the compact and square plots in controlling the soil heterogeneity. Based on the maximum curvature method the optimum plot size for yield trial was estimated to be 5 m2 with rectangular shape.

Soil controls biomass and dynamics of an Amazonian forest through the shifting of species and traits

The effects of soil on tree species composition and trait distributions in tropical forest, and how these interactions affect tree biomass and dynamics, are poorly understood because variation in soil is confounded with variation in climate over large areas. We excluded confounding due to climate by studying variation among 72 1-ha plots within 64 km2, and minimized within-plot variation in soil and stand properties by using long narrow plots oriented along altitudinal contours in Reserva Ducke, Central Amazonia, Brazil. Soil variation caused shifts in tree species composition, which determined stand-level wood density. Soil clay content, cation exchange capacity, plot mean wood density and one-dimensional ordination of tree species composition explained about 40% of variation in tree biomass, 24% of variation in tree mortality and 18% of variation in coarse wood production. As pioneer species were not abundant, lower biomass and higher mortality on sandy soils is a consequence of dominance of species with low to medium wood density adapted to waterlogged and nutrient-poor sandy soils. Therefore, mesoscale variation in biomass and dynamics is caused by co-occurrence of species with similar traits in different parts of the edaphic gradient. Identification of mechanisms controlling tree biomass and dynamics in Amazonian forest will require better understanding of tree–soil physiologic interactions.

Stone Raft: allegory on the spread of European urbanistics in Early Modern times

Cities were the foundational cores of Western Civilization and, at least for westerners, civilization is still unthinkable without cities and urban networks. Inevitably cities have been one of the main tools used by Europeans to establish their colonial systems, starting with the first, the Portuguese and Spanish, in Early Modern times. This paper aims to highlight the role of Iberian colonizing processes as vehicles of European city planning culture.There are basically two large urbanistic pattern families for colonial towns: the orthogonal grid known since Ancient Greece, based on square blocks; and the sequences of long and narrow plots, systematically used in Europe since the beginning of the second millennium. The latter is more flexible and topographically more adaptable than the former. Both patterns are present in Europe, but also in the parts of the world that experienced European colonization.The Portuguese conveyed and developed the plot system in the remaining four continents, while the Spanish codified and carried the block one to the New World. That established a distinction that has been dissected for decades. However, when these two modes are regarded from a global perspective, they appear as two complementary and diverse aspects of the spread of European urbanistics rather than an opposition.The allegory taken from José Saramago’s famous novel The Stone Raft aims not only to give us an image of that European transfer of knowledge to the New World, but also to make us think about new research attitudes and goals around that extraordinary and long lasting legacy.

The Implication of Small Scale Land Sub-division for Formal Housing Towards Sustainable Living and Environment

Research on Indonesian housing market in 1990 showed that at least 85% of the housing stock, was produced independently. This includes the procurement of resources and construction. Small scale land sub-division for informal urban housing usually happen when the price of agricultural products could not cope with the production cost. The narrow plots of agricultural land available for conversion are usually yielding only 20 – 45 housing units. The procurement patterns of this kind is to provide low-cost housing for low income people. However, some important facets were not given enough attention or not widely known. As a result there are no policies or interventions to reduce problems for future residents from such a housing procurement pattern. In terms of orderly urban development, there are problems associated with this kind of housing procurement. Street patterns do not always support the existing roads system, the unavailability of adequate public infrastructure, and the safety and comfort of occupants are neglected factors. This study challenges that a pattern of land acquisition for self-help housing is inevitable. If such patterns are recognized, accommodated and united with the development of general urban housing patterns, it will undoubtedly contribute to the benefit of all parties, especially those who need homes but faces financial limitations. This research is particularly relevant in the context of sustainable development. The pattern of self-help housing land acquisition will support effective spatial planning to minimize the problem, especially in terms of access to services and housing infrastructure, as well as the comfort and safety of the occupants.

In-field runoff as affected by runoff strip length and mulch cover

The purpose of the study was to quantify and predict the rainfall–runoff relationships in the technique of in-field rain water harvesting (IRWH) during maize growing season on Bainsvlei Kenilworth ecotope. The plot set-up was performed according to different runoff strip lengths (RSL) and mulching level (ML) treatments. The growing season received more rainfall events of low amount and high percentage of rain events of short duration (<60min) and low intensity (≤10mmh−1) compared to long-term. This reveals that the considerations of only relatively large and intense rain events for in-field runoff (Ro) estimation would failed to provide reliable runoff estimation under IRWH system. The mean runoff comparison from runoff strip length shows that the narrow (RSL-1) plots generate significant more runoff than the wide (RSL-3) plots with mean Ro from the RSL-1 being nearly 3 times more than that from RSL-3 plots that is due to lower water storage capacity and surface friction in the narrow runoff strips. The bare management harvested more in-field runoff water and showed a significant difference from 39% and 96% mulch level cover. From a linear regression analysis, runoff was significantly affected by amount of rainfall, mulch level, runoff strip lengths and peak rainfall intensities with R2 of 0.69. The model shows that the main characteristics of the rainfall event (amount and peak intensity) are positively related to runoff, whereas an increase in runoff length and addition of mulch cover both reduce in-field runoff water. The performance of the model yielded good results (D=0.97) provides relatively satisfactory results with MAE value of 0.71mm over the growing period. By analyzing, probability curves for in-field runoff processes during the growing season, simulated long-term Ro showed the amount of in-field runoff collectable water from a bare narrow plot (RSL-1) has more advantage for infiltration in the basins, while wide strips (RSL-3) with full mulch cover (96%) infiltrate more the rainwater on the runoff strips. The overall results obtained explain that the physical property of the fine sandy loam soil with gentle slope (<1%) of this experimental site enhances infiltration due to soft crust formation in the top soil surface. This implies that the soil has an ability to hold considerable amount of water following a wet period or after a rain event which was then accessed by the roots during short dry spells.

PPBio Australasia Long Term Ecological Research Sites – flora and fauna database

PPBio (Program for Planned Biodiversity and Ecosystem Research) Australasia Long Term Ecological Research Sites (GIVD ID AU-AU-001) is a system for long-term ecological research (LTER) designed to answer integrated multidisciplinary research questions. PPBio was developed in Brazil with a broad aim of establishing a cost-effective and efficient network of standardized LTER plots to collect comparable information on biodiversity and ecosystem processes around the world. Infrastructure includes permanent plots that follow contour lines (survey lines with all measurements recorded on the horizontal plane) which facilitate orthorectification and validation of satellite imagery. Grids and modules consist of arrays of plots located one kilometre apart (or 500 metres at small sites). Each plot has a 250 metre midline that is permanently marked at 10 m intervals. Plot width varies to suit the taxon or abiotic variable being examined. Small and/or numerous taxa are surveyed in narrow plots (e.g. frogs, reptiles, herbs and grasses are within a 2 m strip on one side of the midline) while wide plots are used for larger or more dispersed organisms (e.g. large trees, birds or small mammals). Low density species (e.g. large mammals such as monkeys, koalas and kangaroos) and additional environmental variables are monitored using the series of grid trails that connect the plots, using standardized sampling methodologies. The first PPBio LTER site at Karawatha Forest Park in Brisbane City (Queensland, Australia) was established in 2007. A second site was established at Lake Broadwater in the Brigalow Belt in 2008. The establishment of a third grid in Chitwan National Park in Nepal was initiated in 2009. A fourth grid with 40 plots was established in Currawinya National Park (western Queensland, Australia) in 2010, and a fifth project establishing modules at Cooloola in the Great Sandy National Park commenced in 2010. To date, vegetation has been measured at four sites (with approximately 99 one hectare plots now completed). Repeat surveys will provide data on vegetation productivity through time. All woody stemmed trees and shrubs are individually tagged and identified within each plot. A hierarchical design was used to sample trees of different size classes in order to estimate tree density. The diameter at breast height (DBH) was measured at 130 cm unless disfigurement made this impossible. Large trees (DBH ≥ 30 cm) were sampled to 20 m either side of the midline (40 m x 250 m ≈ 1 ha). Trees with DBH ≥10 cm were sampled within 10 m either side of the midline (20 m x 250 m ≈ 0.5 ha). All woody stems with DBH ≥1 cm were sampled along a 4 m strip on the right hand side of the midline (4 m x 250 m ≈ 0.1 ha). The location of each tree is recorded in relation to its distance along the transect and distance from the transect. All trees are given an individual identifying number which is tagged to the tree and recorded in the vegetation database.

Effect of plot size on measured soil loss for two Italian experimental sites

The objective of this investigation was to determine empirically the plot width and length effects on runoff volume, Ve, soil loss, Ae, and sediment concentration, Ce, by using data collected, at the temporal scale of the erosive event, on bare plots differing in width (2–8 m) and length (11–22 m) for two Italian stations (Masse, Umbria; Sparacia, Sicily). Mean results differed by a maximum factor of 1.6 for Ve, 1.8 for Ae and 1.2 for Ce when plots differing in width were compared and by a maximum factor of 1.4 for Ve, 1.2 for Ae and 1.3 for Ce when comparison between plot lengths was conducted. Differences between two plot widths or two plot lengths were not statistically significant (P = 0.01). Soil loss was the variable most sensitive to plot size (maximum factor of discrepancy equal to 11.6 for plot width and 25.0 for plot length). Plot width and length effects varied with event erosivity, being low for the most erosive events. Relatively short and narrow plots may give long term results representative of longer and wider plots within the sampled sizes. An appropriate sampling scheme may be based on relatively narrow and short plots instead of wide and long plots, with a reduction of experimental efforts, at least when the events of interest are the most erosive ones. Reducing plot length from 22 m to 11 m is not expected to reduce soil loss per unit area at the two considered locations.

Vanished Gardens: Finding Nature in Philadelphia

I grew up in Philadelphia, where creeks flow under the city in sewer pipes to the Schuylkill River. One year I commuted up 43rd Street to campus and back beneath Chinese ginkgos, European oaks, and London plane trees, unaware of Mill Creek buried fifty feet below me. Anne Whiston Spirn focuses on Mill Creek in The Language of Landscape (1998), and her students' digital atlas reveals its ancient watershed layer by layer, backwards over centuries from city street to stream canyon. Sharon White expands and elaborates on this restorative process: “I could, if I were strong enough, rip the fabric of the city at the edge and peel it away to rocks … Wilderness just underneath the surface” (33). The award-winning White, whose poetry collection is titled Bone House (1998), calls such entombed watercourses “the bones of the wilderness” (32), but her sauntering dissection of the urban landscape reveals other skeletons as well: glacial till, fossils, prehistoric flints, seventeenth-century Swedish foundations, bricks from bulldozed tenements, and the traces of legendary eighteenth- and nineteenth-century gardens and gardeners who, in the face of Philadelphia's rapid rectangular growth, preserved the picturesque in William Penn's so-called “greene countrie towne” (32). White herself lives and grows flowers “on the bones of a garden” (51), a narrow plot once part of John Haviland's Labyrinthine Garden, and she imagines the long-demolished seven-story pagoda towering over its Orientalist pleasure grounds. In her neighborhood and elsewhere—park, wetlands, sidewalk, riverbank, oil refinery—she discerns “the fragile outlines of a large wild garden” insistently re-emerging from beneath the machine (82). Across town an old railroad station shelters a farmers' market, and rows of abandoned houses once built on farmland are collapsing into rubble where wildflowers bloom and raccoons nest, and where community gardens are occasionally established.

Effects of Deep-Flooding Irrigation on Growth, Canopy Structure and Panicle Weight Yield Under Different Planting Patterns in Rice

For rice cultivation in Japan, deep-flooding irrigation is used as a growth control method. To clarify the effects of deep-flooding cultivation under the different planting-pattern, we arranged conventional (Con, 22 hills m-2), narrow (Nar, 33 hills m-2) and very narrow (broadcast direct-seeding Model:BDSM, 100 hills m-2) planting plots under shallow-flooding (SF: 5 cm) and the deep-flooding (DF: 27 cm) conditions from active to maximum tillering stage and evaluated the growth, panicle weight yield, panicle components and community structure. DF was effective in controlling the weak tiller over the whole planting plots arranged. The panicle weight yield (m-2) was high in DF and high yield was kept even in BDSM. The panicle weight yield (m-2) increasesin DF was based on the panicle weight (panicle-1) increased by increasing secondary rachis-branches and their grains (Con and Nar), or on the panicle numbers (m-2) increase (BDSM). Shoot nitrogen content (tiller-1), reported to have the correlation with panicle components, was high in the Con and Nar in DF, and this might contribute to the increase in secondary rachis-branch grains. In BDSM in DF, the marked decrease in the percentage of productive tillers and serious lodging observed in SF were improved. The lodging resistance value in DF was higher than that in SF over the whole planting plots. The light transmission in DF was superior to that in SF in spite of the large LAI. Thus, the growth improving effect of DF was obvious over the wide planting pattern range.

Effect of plot geometry on epidemic velocity of wheat yellow rust

The size and shape of field plots can impact on both the cost and outcome of epidemiological experiments. In previous studies, epidemic velocity of yellow rust (caused by Puccinia striiformis f.sp. tritici) on wheat (Triticum aestivum) has been examined in long, narrow plots (6·1 m by 73–171 m). The present study compares spread in square, 61 × 61 m plots versus narrow, 6·1 × 61 m plots at two locations. The objective was to test whether plot shape has a substantial impact on spatiotemporal spread of yellow rust. Velocity increased curvilinearly with time for both plot shapes and at both locations. Curves of epidemic velocity versus time were nearly identical in square versus narrow plots in both the upwind and downwind directions. Contrary to expectation based on simulations, the results did not indicate faster disease spread in square plots, though the plot sizes studied may be beyond that at which there is a rapid change of disease increase with increasing plot area. Velocity also increased curvilinearly in all eight compass directions of the square plots. Results indicate that narrow plots, which are substantially less costly than equidimensional plots, may be justified for studying the spatiotemporal spread of wheat yellow rust and other diseases with similar epidemiological characteristics.

Sowing and Flowering Delays Can Be an Efficient Strategy to Improve Coexistence of Genetically Modified and Conventional Maize

The coexistence between genetically modified (GM) and non‐GM maize (Zea mays L.) fields is subjected to regulation in several countries. A strategy to reduce cross‐pollination from GM to non‐GM fields was evaluated, on the basis of reducing the flowering coincidence by sowing at separate times. The trial included narrow plots in which transgenic maize was sown before, simultaneously, and after adjacent non‐GM maize. A three‐week delay between GM and non‐GM sowing dates resulted in flowering delays below 5 d for early sowings, but up to 10 to 15 d for late sowings. Cross‐pollination was monitored by xenia effect and validated by real‐time PCR. The combined effect of flowering delay and distance from the pollen source was evaluated. Cross‐pollination dramatically decreased with distance between pollen source and receptor. Flowering delay interacted with distance to the pollen donor source and further reduced GM pollen flow in all cases. Thus, it acted as a regulatory factor. A flowering delay of 92.9 growing degree units (GDU) (7 d in our experimental conditions) was enough to reduce the adventitious presence of GM kernels in non‐GM maize plots down to residual values. This study illustrates the possibility of improving coexistence through temporal separation of flowering dates on the basis of appropriate delays in sowing dates.

One Story House

I was carrying the tortoise in both hands, holding it out in front of me like an altar boy's Bible or a divining rod as I walked around the periphery of the room. Each plate of its ruddy shell was distinct. It leaked as I carried it. More water came forth than a tortoise that size could possibly store. The creature was a fountain, a cleft rock in my hands, and when I awoke I real ized that the room in which I paced was my childhood bedroom. I had been wandering through that house every now and again ever since I'd left it at age fourteen. A quarter century had passed, and I still wasn't out of it, in my dreams. It was a classic suburban house of its era: single story, L-shaped. The houses children draw look like faces with upstairs windows for eyes and a door for a mouth. They have a solidity and a centrality that make them home like the head is home. This house, with its public rooms that opened one into another as though they were only distended passageways and its bedrooms appendix-like cul-de-sacs, had no center, but my psyche was stuck in it. The previous owners' plantings all around it were strange, exotic: bottlebrush and artificial strawberry tree, a spruce the same powder blue as the corduroy pants boys wore then, succu lents and other plants that were nameless, unrecognizable, inedible, with shiny leaves or spiky ones. One plant up a narrow side plot in perpetual shade bloomed annually with a single colossal lily that looked as though it were made of crumpled black leather from some thin-skinned creature. In front of each of the two children's bedrooms facing the street was a mis shapen juniper, and at night the headlights of passing cars made the shad ows of their branches whirl around the walls like pterodactyls. Awnings, eaves, and patio prevented sunlight from reaching in directly to this place made of formica and tile and linoleum and dark-green wall-to-wall carpet ing with a nap like aerial photographs of forests. Everything about it seemed to be made of chilly alien materials, and the swimming pool was strangest of all. The pool was unheated, too cold for skinny kids to jump in most of the year, but it always needed sweeping and skimming to get the dirt and debris out, and the tools for doing that were fantastically long, like cutlery for a moloch with its head up in the clouds. It was the usual pale turquoise