Добірка наукової літератури з теми "Bush fire sites"

Understanding how fire influences animal behaviour, such as movement and resource selection, is important for ecosystem management because it can improve our capacity to predict how species will respond. We assessed microhabitat selection by two small mammals, the bush rat (Rattus fuscipes) and agile antechinus (Antechinus agilis), in response to a low intensity prescribed fire. We used spool and line tracking and touch pole vegetation surveys to quantify microhabitat selection along 21 trails for bush rats and 22 for antechinuses before and after fire. In unburnt areas, bush rats showed positive selection for sedges, logs, and habitat complexity, with selection further increasing in burnt areas for sedges, ferns, shrubs, habitat complexity and unburnt patches. Agile antechinuses showed no significant microhabitat selection in unburnt or burnt areas and no change in response to fire. Their lack of response to ground fires may be due, partially, to their scansorial behaviour and use of tree hollows as refuge sites. Strong selection by bush rats for small unburnt patches suggests that even low intensity, patchy fires such as planned burns can impact bush rats and that high burn patchiness may help bush rats persist in recently burnt areas. Future fire planning should consider both behavioural and population responses of animals to fire.

This study was undertaken to assess threats, rangeland susceptibility to threats and their severity in Adamawa rangelands, Northeast Nigeria. Structured questionnaires were used to elicit information from both pastoralists and the management of the range sites. Data on threats factors was analysed using the following indices: prevalent threat, range sites susceptibility, the mean score of threat factors and the relative threat factor severity. Threats to biodiversity, their prevalence and the number of range sites they occurred showed that invasion by undesirable plants, over-exploitation of forage resources, and bush fires occurred in the three range sites with 100% prevalent threat indices. Diseases and pests, conflicts and settlement policy problems occurred in two of the range sites with 66.7% prevalent threat indices. While farmer encroachment, erosion drought, population increase, poaching and problems associated with rangeland policies occurred in one of the range sites with prevalent threat indices of 33.3%. The threats with the highest severity indices include over-exploitation of forage resources, conflicts, invasion by undesirable plant species, drought, diseases and pests. Others are settlement policy, population increase, bush fire and rangeland policy. Planned burning combined with reseeding of the range sites should be carried out to improve on the composition and abundance of forage resources of the rangelands.

Reduced fire frequency and severity associated with livestock grazing are cited as a cause of woody plant encroachment and thickening in rangelands, but such paradigms are difficult to test experimentally owing to limited opportunities to burn. Mulga (Acacia aneura) dominates 25% of the Australian continent and epitomises this quandary. We measured the effect of rare wildfires on tree and shrub mortality and subsequent regeneration in mulga-dominated communities to critically examine prevailing but unsubstantiated paradigms of vegetation structural change. Mortality of mature mulga trees was positively correlated with fire severity, which was negatively correlated with tree basal area per hectare. High-severity fires killed the majority of mulga, but only occurred in more open areas, whereas low-severity fires typical of many mulga communities did not kill substantial proportions of mature mulga. The majority of mulga saplings were killed across all sites regardless of fire severity. Seedling germination was stimulated by fire, but not dependent on it. Green turkey bush (Eremophila gilesii) was the only shrub species with >50% mortality across all sites. Combined with the rarity of fire events in the historical record, our results, particularly limited fire mortality and enhanced post-fire seedling recruitment, suggest that the role of fire in shaping vegetation structure in mulga-dominated communities has been overstated. The decoupling of fire and vegetation structure is consistent with emerging regional studies in low-productivity semiarid environments.

Research in the world, and more specifically in Africa, on various subjects requires knowledge of previous work from several angles in order to orientate possible research. Thus, the literature review is considered the most suitable approach to have a more complete idea of the innovations or studies carried out on varied topics. To this end, on the issues of vegetal cover protection, environmental management and wildland fire in Ghana, we have adopted this review approach to identify the works already done in Ghana on wildland fire, the methodologies and angles that studies approached their objectives. This paper aims to review and provide a comprehensive report on research works done on the vulnerable vegetation of Ghana by bush fires. Thus, studies published from 1940 to 2021 were extracted from Research Gate, Google Scholar and Google and other indexed journal sites such as Scopus journals using a defined selection criterion. A total of 136 documents: these include reports of international organisations and relevant articles extracted. However, 52 of them were used for this review to better understand their approach and to highlight research gaps that could make those researches innovative. It is noted that most of the research done in Ghana on wildland fire analysis has little or no consideration for the influence of climatic and environmental parameters on understanding wildland fire behaviour, though some respondents from some research show their awareness of the role these parameters play on the fire propagation. However, it should be noted that the majority of studies have focused more on sociological and economic aspects. This observation thus reflects gaps in areas regarding the roles of climatic and environmental parameters in different ecological conditions to better assess the behaviour of wildfires in Ghana.

The response of terrestrial mammals and arboreal marsupials to past burning history as well as a year prior to, and then for 4 years after, a major wildfire in 2003 at Booderee National Park, Jervis Bay Territory was quantified. The present study encompassed extensive repeated surveys at a set of 109 replicated sites stratified by vegetation type and fire history. It was found that most species exhibited significant differences in presence and abundance between major vegetation types. Detections of long-nosed bandicoot (Perameles nasuta) increased significantly in all vegetation types surveyed, in both burnt and unburnt areas. Temporal patterns in captures of three species of small mammals (bush rat (Rattus fuscipes), swamp rat (Rattus lutreolus) and brown antechinus (Antechinus stuartii)) showed a trend for lower numbers of captures on burnt sites compared with unburnt sites. Three species of arboreal marsupials, common ringtail possum (Pseudocheirus peregrinus), greater glider (Petauroides volans) and common brushtail possum (Trichosurus vulpecula), were moderately common and all showed marked differences in abundance between vegetation types. Whereas P. peregrinus and P. volans exhibited a temporal decline between 2003 and 2006, T. vulpecula exhibited a general increase from 2003 levels. However, arboreal marsupial responses did not appear to be directly fire related.

Few studies were carried out on the impact of wood cutting and bush fires on the dynamics of the herbal strata in savannahs of Adamawa, Cameroon. This study has as objectives to evaluate: 1. the recovery of the vegetation of shrub and grass savanna, 2. the evolution of the number of herbs with regards to time, 3. the floristic and specific contribution of the herbal specie. The inventories of herbaceous plants were carried out through quadra method in 9 sub-plots of 10 m × 10 m for each vegetal formation. The experimental design was split-plot with two (02) factors (savanna trees and shrubs), three (3) treatments (felling without fire, with fire and witness) and three (3) rehearsals/repetitions (portions). The analysis of variance (ANOVA) was used to compare means between treatments by using STATGRAPHIC XVII, and XLSAT to obtain result shown that 103 herbaceous plants divided in 73 genres and 23 families. The rate of recovery of savanna vegetation the herbs are more numerous 60% in the CSF, 50% in the CAF and 45% in witness site (wood savanna), Adversely, 30% in a witness site, 40% in the CSF and 50% in the CAF (shrub savanna). The number the species have grown from 3 to 45 in the tree’s savanna and 2 to 34 for the shrub savanna. The specific contribution of herbaceous varies according to the sites and the species.

Large amounts of time and money are currently being expended in "restoring" damaged bushland in many parts of Australia, particularly those remnants in or near large centres of population such as Sydney. This paper argues that it is time to critically examine policies and practices of bushland conservation for the range of bushland values they are serving. Since the introduction of minimum intervention "bush regeneration" in Sydney in the 1960s "restoration" has developed to encompass a much broader range of disturbed areas from lightly weed invaded bush to totally cleared sites, and there has been a blurring of distinctions between regeneration and other restoration practices. In particular, both restoration and regeneration now include planting as widely accepted practice. Focusing on New South Wales, particularly the Sydney region, this paper reviews the role of values in current conservation planning and bushland management in New South Wales, the development of "regeneration", and "restoration" and the nature of scientific and educational values of remnant bushland, and examines how the practice of planting in bushland is degrading those values. Alternative methods to achieve natural regeneration, particularly the use of fire, are discussed. The paper concludes with an emphasis on the importance of developing a planning process for bushland conservation and management which establishes significance based on its specific values, and adopts integrated objectives and strategies, policies and practices, to protect that significance and ensure that restoration does not degrade the values for which the bushland is being preserved and restored.

Background and aims – Understanding the spatial patterns and associations of tree species with their conspecific and heterospecific neighbours is critical for sustainable management of their stands. This study assessed the intra- and interspecific spatial structure of six life stages in Afzelia africana, a keystone multipurpose and endangered tree species in a tropical savanna of Benin.Material and methods – Three plots of 4 ha each were demarcated on three sites along a conservation gradient (hunting zone – core conservation zone). Individuals of A. africana (irrespective of their diameter at breast height) and heterospecific trees (dbh ≥ 5 cm) were mapped. Tree spatial patterns and associations were determined using univariate and bivariate pair correlation functions. The distance to the nearest neighbour was further used to assess tree-to-tree distance.Key results – We found variable spatial patterns across sites. In the core zone where wildlife density is high, most life stages had a random distribution. In contrast, in the hunting zone where wildlife density is low, the species spatial distribution changed from a predominantly aggregative pattern during early stages to a less aggregative or random spatial pattern for very large adults. Most pairs of life stages showed neutral associations, except for small and large adults, which had positive association between themselves on two sites. We also found that A. africana tree spatial distribution was unrelated to heterospecific trees.Conclusion – We suggest that bush fire, seed dispersion, predation, and local environment would have contributed to the observed patterns.

‘Xanthorrhoea…is in habit one of the most remarkable genera of Terra Australis, and gives a peculiar character to the vegetation of that part of the country where it abounds’ Robert Brown (1814). Grasstrees (arborescent Xanthorrhoea, Dasypogon, Kingia), with their crown of long narrow leaves and blackened leafbase-covered trunk (caudex), are a characteristic growth form in the Australian flora. Xanthorrhoea is the most widespread genus, with 28 species that are prominent from heathlands to sclerophyll forests. While leaf production for X. preissii reaches a peak in spring–summer, growth never stops even in the cool winter or dry autumn seasons. Summer rain, accompanied by a rapid rise in leaf water potential, may be sufficient to stimulate leaf production, whereas root growth is confined to the usual wet season. Grasstrees are highly flammable yet rarely succumb to fire: while retained dead leaves may reach >1000°C during fire, the temperature 100 mm above the stem apex remains <60°C and the roots are insulated completely. Immediately following fire, leaf production from the intact apical meristem is up to six times greater than that at unburnt sites. For X. preissii, pre-fire biomass is restored within 40 weeks; the mass of live leaves remains uniform from thereon, whereas the mass of dead leaves increases steadily. Leaves usually survive for >2 years. In X. preissii, the post-fire growth flush corresponds to a reduction in starch storage by desmium in the caudex. Minerals, especially P, are remobilised from the caudex to the crown following a spring fire, but accumulate there following an autumn fire. At least 80% of P is withdrawn from senescing leaves, while >95% K and Na are leached from dead leaves. Most stored N and S are volatilised by fire, with 1–85% of all minerals returned as ash. Despite monthly clipping for 16 months, X. preissii plants recover, although starch reserves are depleted by 90%, indicating considerable resilience to herbivory. Analysis of colour band patterns in the leafbases of X. preissii shows that elongation of the caudex may vary more than 5–50 mm per annum, with 10–20 mm being typical. Exceptionally tall plants (>3 m) may reach an age of 250 years, with a record at 450 years (6 m). Fires, recorded as black bands on the leafbases, in south-western Australia have been decreasing in frequency but increasing in variability since 1750–1850. Some grasstrees have survived a mean fire interval of 3–4 years over the last two centuries. In more recent times, some grasstrees have not been burnt for >50 years. The band-analysis technique has been used to show a downward trend in plant δ13C of 2–5.5‰ from 1935 to the present. Grasstrees are most likely to flower in the first spring after fire. A single inflorescence is initiated from the apical meristem, elongating at up to 100 mm day–1 and reaching a length up to 3 m, with one recorded at 5.5 m. This rapid rate of elongation is achieved through leaf (and inflorescence) photosynthesis and desmium starch mobilisation. The developing spike and seeds are vulnerable to a moth larva. Leaf production recommences from axillary buds and the trade-off with reproduction is equivalent to 240 leaves in X. preissii. Flowering and seed production are affected by time of fire. Grasstrees are mainly insect-pollinated. Up to 8000 seeds per spike are produced, although pre-dispersal granivory is common. Seeds are released in autumn and persist in the soil for <2 years. Most fresh seeds germinate in the laboratory but germination is inhibited by light. At any time, seedlings and juveniles may account for most plants in the population, although there may be up to an 80% reduction within 1 year of seedling emergence, often due to kangaroo herbivory. In the absence of fire, mortality of adults may be 4% per annum. Although few grasstree species are considered rare or threatened, their conservation requirements, especially in regard to a suitable fire regime, remain unknown. Grasstrees are particularly susceptible to the exotic root pathogen, Phytophthora cinnamomi, although recruitment among some species has been observed 20–30 years after pathogen invasion. Much remains to be known about the biology of this icon of the Australian bush.

Karakelang, largest of the Talaud Islands, Indonesia, was visited in 1999 with the aim of producing population estimates of globally threatened and Restricted-range bird species. Density estimates were calculated from primary forest and secondary habitats using the variable circular plot method. Eight of the nine restricted-range or threatened species resident on Karakelang were recorded and density estimates calculated for five of these. Two species of rail are endemic to Karakelang, Talaud Bush-hen Amaurornis magnirostris and Talaud Rail Gymnocrex talaudensis. The bush-hen was encountered in secondary habitat but occurred at higher densities in primary forest and the estimated population was 2,350–9,560 birds. The less vocal, cryptic G. talaudensis was noted just twice, in primary forest close to rivers. Both have small populations, are threatened by habitat degradation, hunting, and possibly predation by introduced rats and should be classified as threatened. Population densities of the Endangered, endemic Red-and-blue Lory Eos histrio had remained stable since the last survey in 1997. They occurred at higher densities in primary forest, but were also common in human-made habitats. The estimated population was 8,230–21,400 birds, threatened by habitat loss and trapping for the wild bird trade. Although more commonly encountered in forest, the Near Threatened Blue-naped Parrot Tanygnathus lucionensis was found at higher densities in secondary habitats, and the population was estimated at 8,130–20,700 birds. The Restricted-range Blue-tailed Imperial Pigeon D. concinna was very common on Karakelang (14,500–27,700 birds), whilst the Vulnerable Grey Imperial Pigeon D. pickeringii was recorded rarely; both species were more frequently recorded in primary forest. The endemic Talaud Kingfisher Halcyon enigma occurred at low densities (5,290–8,690 birds), in primary forest and adjacent disturbed areas. It is heavily dependent on primary forest and threatened by habitat loss, and should be classified as Vulnerable. Approximately 350 km2 of primary forest on Karakelang is protected, 250 km2 as a wildlife reserve. However, at present, management is absent and forest is threatened by agricultural encroachment, illegal logging, and fire. Given that all endemic and threatened species were encountered more frequently or occurred at higher densities in primary forests, future conservation efforts should target these protected areas. Management of reserves should involve local stakeholders from government and representatives of island communities. Wildlife trade is a major threat to Eos histrio and strict enforcement of the species' protected status should include monitoring of roost sites, patrols of harbours and markets in Talaud, Sulawesi and the Philippines, and the control of Philippine fishing boats involved in the wild bird trade. Further species-specific research and monitoring is also required.

This thesis examines techniques that provide a method of computer visualisation of bushfire spread. Existing techniques studied include, Kourtz & O???Regan, Green???s Contact, Heat Accumulation, Percolation modelling and Huygens??? Principle by Anderson et.al., French, Roberts, Richards. Many of these techniques are extended as part of a comprehensive study into how they perform in a two dimensional reference frame (ie over flat terrain only). New techniques are defined for Percolation Modelling and Huygens??? Principle. Each technique is examined in a series of test cases which include computer simulations with no wind, constant wind, variable wind, variable vegetation (including patchy fuel and two fuels) and where fuel burns out. These test cases provide: (a) an incremental approach to understanding the operation of each technique; (b) a basis for comparison; and (c) verification of correctness of the technique in two dimensions. Several of the techniques are shown, by these test cases, to be equivalent. For instance, the Kourtz & O???Regan technique using a square template is equivalent to the Contact Technique, Site percolation is similar to the Heat Accumulation technique and Template percolation is similar to the Contact Technique. Overall the Huygens??? Principle techniques provide the most accurate simulations of bushfire spread.

Snow is an important factor in the lives of flora and fauna in those regions where it occurs. Despite this, there is a relative lack of information about the ecological role of snow. In addition, on a global scale the majority of the research on snow ecology has been based in the boreal regions of North America and Eurasia. Insights from these areas may not extrapolate well to Australia. The distribution and physical characteristics of snow are highly variable both temporally and spatially. Its occurrence is affected by a range of factors acting at multiple scales. Working in snow covered areas, however, presents considerable practical problems, particularly for researchers attempting to sample organisms in the subnivean space between the base of the snowpack and the ground surface. As a result, most research has focused on small-scale projects because of logistical and animal-welfare issues. A technique was developed for this study for sampling small mammals beneath the snow using hairtubes fitted with bait and a removable adhesive surface that could be inserted into the subnivean space through a vertical PVC pipe. The technique provided a 39% detection rate with only 0.2% of tubes visited but not collecting hair samples. Using. this technique, it was possible to expand systematic sampling of small mammals in the subnivean space to larger scales at which snow cover can vary spatially and temporally particularly at the landscape scale. The main part of this research was conducted over two winters (2002-2003) at sites established in a series of valleys close to the Summit Road in Kosciuszko National Park, south-eastern Australia. Selection of sites was based on factors considered important in influencing the distribution of snow in the landscape and representative of the key vegetation types occurring in the subalpine zone. The resulting design consisted of 72 sites stratified by elevation (1501-1600 m, 1601-1700 m, 1701-1800 m), aspect (accumulating, ablating) and vegetation type (woodland, wet heath, dry heath, grassland) with each combination replicated three times. Each site consisted of three hairtube plots approximately 10 metres apart, at which small mammals were sampled. In addition, a range of biotic and abiotic factors including snow cover characteristics were measured throughout the winter at these same sites. In January 2003, a major bushfire burned 70% of the subalpine area of Kosciuszko National Park and damaged 83% of the sites established in 2002. As a result sampling during winter 2003 was limited to high elevation sites, along with a fifth habitat type (boulderfields). The snow cover that occurs in the main alpine and subalpine region of the· Snowy Mountains is primarily maritime in areas where there is sufficient accumulation, and ephemeral at lower elevations and ort higher ablating aspects. Maritime snow is generally deep (> lOOcm), with a density >0.30gcm-3, as a result of destructive metamorphism throughout the winter. The formation of depth hoar, which is considered to be important in acilitating the development of the subnivean space, does not occur under these conditions. Ephemeral snow is characterised by warm shallow snow that often melts before new snow is deposited. When snow was present, detections of dusky antechinus, Antechinus swainsonii and the bush rat, Rattus fuscipes were negatively correlated with snow depth and duration, and positively correlated with the complexity of structures and microtopography. At high elevations, detections were largely confined to boulderfields, and at mid- and low elevations, small mammals were detected primarily in habitats where the subnivean space was most extensive. Antechinus swainsonii and R. fuscipes responded differently to snow cover with the latter seeming better able to overwinter where snow cover was shallow and patchy. In contrast, A. swainsonii occurrence was correlated with the size of the subnivean space. The development of the subnivean space in the Snowy Mountains is dependent on the presence of structures such as shrubs, boulders and microtopographic features that are capable of supporting a snow layer above ground level. The temperature in the subnivean space was virtually constant beneath the snowpack, ranging between 0 and + 1 °C. When snow was patchy or absent, temperatures at ground level were highly variable with a minimum as low s -13°C and maximum as high as +47.5°C. Antechinus swainsonii and R. fuscipes were detected more regularly at sites that were thermally variable. At sites with deep and persistent snow cover (maritime snow), subnivean temperatures were stable, but small mammals were detected at low frequencies. At high elevations, boulderfields were favoured by small mammals during the nival period but were no different thermally from other habitats. The limitations imposed by snow cover on small mammals were further verified by a radio tracking study conducted during 2003 at Perisher Creek. That study investigated the home range size and activity patterns of R. fuscipes and A. swainsonii in relation to snow cover. Once continuous snow cover became established, the home range of both species contracted dramatically and there was an increase in home range overlap. Neither species showed any change in diurnal activity patterns. Rattus fascipes showed signs of social interaction during both seasons in contrast to A. swainsonii, which appeared to remain solitary. In winter, R. fuscipes nested communally at a single location, while during autumn the species appeared to use a number of nest sites. There was no significant change in daily activity patterns between autumn and winter in either species. R. fuscipes remained primarily nocturnal during both pre-nival and nival periods while A. swainsonii continued to be active throughout the diel cycle, although there was a slight shift in its peak activity time. Human activities can, have significant effects on the subnivean space and its residents. The physical characteristics of a range of modified snow types were investigated in the vicinity of several ski resorts in Kosciuszko National Park. Human activities associated with snow-based recreation, such as the creation of ski pistes, surface ski lifts and over-snow routes, involve compression of the snowpack and resulted in small or absent subnivean spaces and high snow cover densities compared to unmodified snow cover. To test the effects of the loss of the subnivean space on small mammals, the snowpack was experimentally compressed in high quality subnivean habitats. Detections of R. fascipes and A. swainsonii declined by 75-80%. Burnt sites from the 2002 study were used in 2003 to investigate the effect of removing vegetation on the subnivean space, to simulate the loss of structure associated with ski slope preparation. There was a significant reduction (p<0.0001) in the size of the subnivean space compared to unburnt sites regardless of habitat type. The key conclusions of the work reported in this thesis are listed below: • Snow conditions in the Australian Alps are markedly different from those of higher northern latitudes and altitudes. As a result, conclusions about snow/fauna interactions based on research in regions with particular snow cover types need to be carefully considered before attempting to extrapolate generalisations to other parts of the world. • The subnivean space can be formed either by passive or active processes. The former occurs when there are sufficient competent structures to permit the support of the snow pack above the ground surface, while the latter refers to the ability of small mammals to actively tunnel through relatively low density snow (depth hoar) and thus create their own subnivean space. In Australia the passive process dominates. • The widely held assumption that small mammals are dependent on the thermally stable conditions in the subnivean space was not confirmed. Rattus fascipes and A. swainsonii survive in the Australian Alps because they are able to exploit thermally variable environments. • Management of human activities in nival areas should focus on avoiding disturbance in areas where a subnivean space forms, particularly in high quality winter habitats such as boulderfields. • Global warming resulting from climate change is likely to provide conditions in the Australian Alps that favour an expansion of the distribution and population of R. fuscipes and A. swainsonii, but nival endemics such as Burramys parvus and possibly Mastacomys fuscus may be at a disadvantage. • The extent of alpine and subalpine environments in Australia will decrease in future, imposing greater pressure on a shrinking resource and raising the possibility of conflict between user groups and conservation imperatives.

Most scientists now agree that some sixty-five million years ago, an immense comet slammed into the Yucatan, detonating a blast twenty million times more powerful than the largest hydrogen bomb, punching a hole ten miles deep in the earth. Trillions of tons of rock were vaporized and launched into the atmosphere. For a thousand miles in all directions, vegetation burst into flames. There were tremendous blast waves, searing winds, showers of molten matter from the sky, earthquakes, and a terrible darkness that cut out sunlight for a year, enveloping the planet in freezing cold. Thousands of species of plants and animals were obliterated, including the dinosaurs, some of which may have become extinct in a matter of hours. In Impact, Gerrit L. Verschuur offers an eye-opening look at such catastrophic collisions with our planet. Perhaps more important, he paints an unsettling portrait of the possibility of new collisions with earth, exploring potential threats to our planet and describing what scientists are doing right now to prepare for this awful possibility. Every day something from space hits our planet, Verschuur reveals. In fact, about 10,000 tons of space debris fall to earth every year, mostly in meteoric form. The author recounts spectacular recent sightings, such as over Allende, Mexico, in 1969, when a fireball showered the region with four tons of fragments, and the twenty-six pound meteor that went through the trunk of a red Chevy Malibu in Peekskill, New York, in 1992 (the meteor was subsequently sold for $69,000 and the car itself fetched $10,000). But meteors are not the greatest threat to life on earth, the author points out. The major threats are asteroids and comets. The reader discovers that astronomers have located some 350 NEAs ("Near Earth Asteroids"), objects whose orbits cross the orbit of the earth, the largest of which are 1627 Ivar (6 kilometers wide) and 1580 Betula (8 kilometers). Indeed, we learn that in 1989, a bus-sized asteroid called Asclepius missed our planet by 650,000 kilometers (a mere six hours), and that in 1994 a sixty-foot object passed within 180,000 kilometers, half the distance to the moon. Comets, of course, are even more deadly. Verschuur provides a gripping description of the small comet that exploded in the atmosphere above the Tunguska River valley in Siberia, in 1908, in a blinding flash visible for several thousand miles (every tree within sixty miles of ground zero was flattened). He discusses Comet Swift-Tuttle--"the most dangerous object in the solar system"--a comet far larger than the one that killed off the dinosaurs, due to pass through earth's orbit in the year 2126. And he recounts the collision of Comet Shoemaker-Levy 9 with Jupiter in 1994, as some twenty cometary fragments struck the giant planet over the course of several days, casting titanic plumes out into space (when Fragment G hit, it outshone the planet on the infrared band, and left a dark area at the impact site larger than the Great Red Spot). In addition, the author describes the efforts of Spacewatch and other groups to locate NEAs, and evaluates the idea that comet and asteroid impacts have been an underrated factor in the evolution of life on earth. Astronomer Herbert Howe observed in 1897: "While there are not definite data to reason from, it is believed that an encounter with the nucleus of one of the largest comets is not to be desired." As Verschuur shows in Impact, we now have substantial data with which to support Howe's tongue-in-cheek remark. Whether discussing monumental tsunamis or the innumerable comets in the Solar System, this book will enthrall anyone curious about outer space, remarkable natural phenomenon, or the future of the planet earth.

Packing Insulation Was Mike Patrick’s first job at Midwest Manufacturing. He was one of 300 men, mostly young, hired in January 1959 to help Admiral, a Chicago-based company that owned the Galesburg factory, meet America’s seemingly insatiable postwar appetite for appliances. He had failed an eye test during the nurse’s exam at the factory and had to get glasses before he started. Patrick had suspected he needed glasses because he always had trouble see­ing the chalkboard from the back of the room in high school. But because he was an athlete, he didn’t want to tie glasses around his head during basketball games. New hires got the nastiest, most grueling jobs, and stuffing insulation— which was like prickly cotton candy—into bare metal cabinets was one of them. The cabinets came from the metal-cutting area of the factory known as the “black line,” because the steel, darkened with oil, hadn’t yet been painted. The black line was the birthplace of these early Admiral refrigerators. Flatbed semis unloaded massive rolls of thick steel from Chicago—the plant used 10 rolls a day, 50 million pounds a year—that cutters and folding machines would shape into five sides. Gun welders then joined what would become the back, the two sides, and the top and bottom of the refrigerator. They left the door for later. The fused steel cabinet dangled from an overhead conveyor as it rode to the paint shop to be cleaned of its oily residue and painted. It would continue on the conveyor to a cabinet bank, where the empty cabinets gathered until they were needed on the line. When the scheduler called for them, men would slide the cabinets to the line across a concrete floor, which had been treated with a smooth, protective coating to prevent damage. A young man then spread scalding, gooey tar into the corners and up and down the creases of the bare metal cabinets. He shot the tar out of a pistol-gripped nozzle attached to a long canvas hose that he snaked in and around the metal shell.

On the Last day there would be a potluck and a drawing for some free appliances and $100 in cash. It was clear, though, that those still around in September 2004 could hardly wait for this drawn-out shuttering finally to be over. Crews were taking down the lighting, removing tables and cabinets, and gathering screws and air gun bits to toss in the garbage. “I don’t know if they are going to start with fresh tools down there in Reynosa or what the deal is,” Tracy Warner said. The crews also asked workers to remove photographs and newspaper clippings from their workstations. “They are dismantling it all around us, like they can’t wait for us to get out of there.” The lawn outside, usually covered in pop cans, plastic wrappers, and cigarette butts, was cleaned up and sprayed green by Chem Lawn. Management was trying to sell the old place. Warner’s imminent layoff was part of a sea-change in Illinois in the first years of the new millennium. The pace of the hollowing out of manufacturing in the fourth-largest manufacturing state in the country had been unprecedented. From June 2000 to November 2003, Illinois lost more than 100 manufacturing jobs a day, or one out of every six. Gone were over 150,000 jobs in a state of 12,500,000. In Rockford, the machine-tool industry wilted, and unemployment spiked at over 11 percent. In Harvard, located near the Wisconsin border, Motorola closed its cellphone plant. Developers wanted to turn the site into the world’s largest indoor water park. In Peoria, Decatur, and Kankakee, laid-off workers applied for jobs at Walmarts and Home Depots that would pay them maybe half their former wage. In suburban Chicago, Winzeler Gear went from making 2 million gears a month with fifty-five workers to making 16 million a month with thirty-five employees. A robot the size of a minivan increased the factory’s output while also eliminating human labor. Even with the productivity boost, the owner doubted the company would be able to stay competitive.

On the Road to Volador were tree-lined, rocky hills, as well as a fútbol field where a few kids kicked around a ball. A boy on a wobbly-wheeled bicycle navigated the dirt path next to the road, spinning his legs as fast as he could to keep up with our truck. Just outside of town, a group of ten women and girls were picking chile piquín on a steep slope above the road. As Josh and I spoke in English to prepare our questions, the women chattered in rapid-fire Spanish to one another, clearly welcoming the work interruption. They had stopped plucking the tiny red and orange chiles, which they collected in two-liter Coke bottles with the tops cut off. Before we could introduce ourselves, an older woman said in Spanish, “It sounds nice, like what we’ve heard on soap operas.” They said they had seen gringos from time to time in Papantla, the municipal seat, and at the pyramids of nearby El Tajin, the spectacular pre-Colombian archeological site. But they claimed during our trip in 2007 that we were the first gringos to visit tiny Volador. The rugged but fertile land around Volador was planted with corn, beans, papaya, chiles, bananas, oranges, mangoes, and other crops. It was more difficult land to farm than that of Agua Dulce. Volador was also more isolated, and it had fewer people. The main difference, though, was that Don Beto Cruz, an absentee landlord from Papantla, owned nearly all of the land surrounding the village. There was no ejido here. Locals traded their labor with Cruz for little plots of land to farm. Wage work in the fields earned about $8 a day, but it was irregular, maybe one or two days a week. Several of the fieldworkers were high school–aged girls earning summer money. Despite the blazing heat, they dressed in jeans or sweatpants and had layers on top to protect against the scratchy fieldwork and the sun. One of the girls wore a white-and-blue shirt that read, “Telesecundaria Mariano Matamoros.” The shirt featured a television with a smiley face inside.

Crete is the largest and most southerly of all the Greek islands. It is also one of the most visited, due to both its beauty and its famous ancient sites. By far the best-known of these attractions is the spectacular Palace of Knossos, reconstructed over a period of thirty-five years by its discoverer, Sir Arthur Evans, who put more than a million dollars of his own money into the work. Scholars have criticized his reconstruction as a fanciful and not altogether accurate representation of the original, but millions of tourists delight in being able to see more at an ancient site than foundations, scattered stones, and a few columns. But Knossos is not the only dramatic ruin of antiquity on the island. Gortyna and Phaistos should not be missed, and for Christians the harbor of Kaloi Limenes (called Fair Havens in the New Testament) is a place of importance in the life of the Apostle Paul. Likewise, the Basilica of St. Titus at Gortyna commemorates the ministry of Titus, a Greek convert who was a disciple of Paul (Gal 2:3), as described in the New Testament book of Titus. Furthermore, Iraklion possesses an archaeological museum second only to the National Museum in Athens. The only site on Crete mentioned in the Bible, though Crete itself was said to be the place of the ministry of Titus (Titus 1:5), is the harbor of Kaloi Limenes (Good Harbor), referred to in the Book of Acts as Fair Havens (Acts 27: 8). After two thousand years, the site is known by the same name today. Even in New Testament times the place was distinguished only as the harbor for the nearby city of Lasea, a flourishing commercial city in the Roman period. Today the tranquil bay in its remote location harbors nothing more than sunbathers who visit its beaches to enjoy the beautiful waters of the Mediterranean. The site can be reached best by automobile, or by taking a bus from Iraklion to Moires/Mires.

On a Blistering morning in July 2007, four middle-aged men, already quite drunk, stood shaded under the eaves of a long, white stucco building. The building, which was derelict, sat in the middle of Agua Dulce in semitropical northern Veracruz. Our guide, Orlinda Garcia, asked the four men where we could find an hoja (husk) processing plant. Mayor Javier Gonzalez and Treasurer José Cruz stood with us as well. Gonzalez’s sky-blue municipal office was just a few hundred feet away, on the other side of the vacant town plaza. The adjacent plaza was littered with rusty rides and empty prize booths from a traveling summer carnival that had recently ended. “This is it!” a man in a Pittsburgh Pirates cap shouted. He pointed to a concealed entrance. Part of the wavy clay tile roof was missing and had been replaced with corrugated metal sheets. Plastic bags and bottles specked the ground outside. A slick, red PRI campaign banner hung on an electric pole next to the building with a candidate’s portrait. “Fiel a ti” (Loyal to you), the banner read. The plain building stretched alongside a wide, bumpy road—deserted except for a few chickens. It did not look like the site of a profitable foreign-trade operation. A young encargada (supervisor) named Marisol greeted us from behind a black metal gate. We asked her if we could see inside the facility. “The patron is not here,” she said. “I cannot let you in.” She was apologetic but firm. In a pink blouse, capri pants, and faux gem-studded flip-flops, she appeared to be dressed more for a Saturday of shopping in Monterrey than managing an export business in this half-ghost town in far-flung Veracruz. “The boss is very particular, and he doesn’t allow people from the outside to see the operation.” Another neatly dressed young woman looked at us while she embroidered some clothing in a chair behind Marisol. She sat next to a pile of plastic bags swollen with corn husks (called hojas or totomoxtle).

Soul Flower Farm sits on the edge of a series of rolling hills in California’s East Bay, in the city of El Sobrante located about ten miles from Berkeley. Goats graze on the hillside, and one can hear chickens clucking in their coop. On a wooden shed nearby is a painting of a giant golden sunflower with a vibrant magenta center, across from which the farm announces its name to visitors. On a crisp summer day in 2015, the mural almost sparkles, its vivid colors accentuating the green of the trees around it, as well as the pale, brittle yellow of the grass beneath it, the result of a five-year drought in California, which the state eventually declared over in 2017. Soul Flower Farm’s website describes it as “a small urban farm … striving to incorporate biodynamic farming methods and permaculture design to be self-sustaining.” Under a photograph of its proprietors, Maya Blow and her husband, Yasir Cross, the description continues: “Raising goats, chickens, ducks, bees, and boys, homeschooling, sustainable building, and practicing holistic medicine keeps us busy.”...

After many years the author returns to follow Keats’s 1818 walking tour with his friend Charles Brown through the north of England to Scotland to find that though many iconic sites remain the same, much has changed, including her own perspective as she now sees Scotland as the primary destination of the travellers. The internet has come along, getting places and researching information has changed, and significantly, since the author follows the tour camera in hand, photography has moved to digital. The touchstones of the tour—Wordsworth’s home at Rydal Mount, the grave and mausoleum of Burns in St Michael’s Churchyard, Ailsa Craig on the horizon opposite Girvan, Ayrshire with Burns’s cottage, Brig o’ Doon, Kirk Alloway—all have a refreshed lustre. Following Keats’s side trip to Northern Ireland, Belfast has blossomed into a vibrant city free of armed guards at checkpoints. Oban, always busy, now has traffic signs in Gaelic and English and on the ferry to Mull, some conversations could be heard in Gaelic. The farmhouse called Derry-na-Cullen on Mull appears more skeletal and overcome with green growth. The church at Inveraray is more accessible and documented. The old Letterfinlay Inn on Loch Lochy has been landscaped without, remodelled within, and put up for sale as a five-bedroom country house. The abbey was missing from Fort Augustus. The dock from which Keats sailed home to London in Cromarty remained as he had seen it. Only the twenty-first-century beholder had changed.

Sitting atop a rickety Indian bus trundling up the Beas Valley to the delightful hill station of Manali in the Kulu Valley of Himachal Pradesh, peering between swaying bodies and piles of luggage, I caught my first glimpse of the snowy peaks of the Himalaya. Yes, those white streaks way up in the sky were not, after all, clouds: they were glints of sunlight on impossibly high and steep ice-fields plastered onto the sides of mountains that tore up into the sky. It was a sight to take one’s breath away and I knew instantly that this was going to be the start of a great adventure. We were a typical shoestring British student expedition of five friends who could fit easily into two overloaded rickshaws, heading for the mountains around the Tos Glacier. Mountaineers dream about climbing in the Himalaya. Since my earliest days of climbing the hills and crags of Snowdonia and northern Scotland, I had yearned to see and climb those magical Himalayan Mountains. Now here I was, and the reality of the Himalaya was even better than I imagined. I had taken three months off from my PhD studies on the geology of the Oman Mountains to go on this expedition. We had driven a Land Rover out from England to Muscat through a snowy Europe and across the Empty Quarter of Arabia from Syria and Jordan to the United Arab Emirates and Oman. After three months’ fieldwork in Oman I caught a passenger ship, the MV Dwarka, last of the British East India Company merchant vessels that plied the Gulf route from Basra via Kuwait, Bahrain, Dubai, and Muscat to Karachi, and then travelled through Pakistan by train into India. That first expedition to Kulu was a revelation. We camped on the Tos Glacier, four days’ walk above the village of Manikarin in the Parbati Valley of eastern Kulu, for about four weeks. During that time the weather was perfect almost every day.

The semester is over, my grade rosters have been handed to the registrar, and I am home, writing sporadically and glancing through a book by P. G. Wodehouse, whose incomparable prose, as elegant as it is funny, is always very soothing. The thirty students in Conservation Ecology were very good this year. Most of them were informed, outdoors-loving, committed, hard working people who cared for each other and seemed to enjoy the class. With a few exceptions, however, they can’t write English, and I am still recovering from the effects of reading the term papers upon which their grades were largely based. For twenty-five years, I have been assigning a major term paper in lieu (“in loo,” as one student wrote) of an exam. I used to get eighteen- to forty-page papers, acceptably or even nicely written; now the students struggle to reach fourteen pages with the help of triple spacing, margins you could drive a bus along, and type sizes usually reserved for the visually disabled. And the writing! The first mistake the students are making is to use the “spell-checkers” of their computer software as a substitute for proofreading. The results are papers in which all the words are spelled correctly, even if they are not the right words. Reading these spell-checked papers can be like trying to translate from Spanish to English based on the assumption that words that are spelled the same in the two languages have the same meaning. (This can lead to some confusion if, for example, the Spanish words are sin, cabal, or saber.) In one of the papers, I had to erase a long, marginal comment I had written when I realized that illicit was meant to be elicit. In another, I had trouble with the philosophical implications of the word modal, used throughout the text, until I turned it into model, which made more sense. Then there were words such as begum (“a Muslim lady of high rank,” my dictionary told me), which didn’t seem to fit easily into the context of a paper on the genetics of coyotes, and which didn’t have an obvious substitute.

Unfired combined-cycle power plants of Siemens/KWU design each comprise five different package-engineered functional areas of mechanical and associated electrical equipment which are matched to different fuels, site conditions and operating requirements in order to achieve optimum power generation with each application. A modular programmable microprocessor-based automation station allocated to each functional area sequentially controls and protects all the equipment therein. By means of a redundant bus system all the functionally distributed automation stations are connected to one another and to a central control room where VDU screens provide operators with an in-depth insight into the running performance status of the entire combined-cycle block at all times. Function keyboards and back-up conventional hardwired controls permit operators to intervene in the automatic operation of the station whenever desired.

The nuclear power site resource is very rich in Jiaodong Peninsula of Shandong Province. It is suitable for construction of the large nuclear power base. The transmission scope and direction of Jiaodong Peninsula nuclear power base is analyzed, and optional transmission plans of Plant 1, Plant 2, Plant 3 and Plant 4 are proposed. The transmission plans are recommended based on technical and economic comparison, which provide good references for construction of the large-scale nuclear power base and power grid development planning. Jiaodong Peninsula nuclear power base is planned to be built in the year of 2016–2030, planning capacity of which is 30500MW. The site of nuclear power base is 100∼400km away from the power load center. The nuclear power will use AC transmission and mainly meet the demand of local power load. The early 15500MW gensets will be accessed to the power grid at 500kV, as the following 15000MW gensets will be accessed at 1000kV UHV (Ultra-high voltage) grid. As the accessing of many large-capacity gensets will produce huge impact to the short-circuit current, sectionalized double-bus configuration is recommended in the 500kV main electrical wiring to reduce the short-circuit current of 500kV bus of nuclear power plant. Double bus section cross wire connection is presented to make sure that every two generators on each bus will be connected to different substations on two transmission lines which are set up on different poles and in different paths, to improve the reliability of the power plant. Through analysis and provement, the construction of large nuclear power base must be based on large and stronge power grid, especially the UHV (Ultra-high voltage) AC grid, to meet the demand of huge nuclear power transmission, and to improve the ability of power exchange and ensure the safety of regional power supply. Also, as the nuclear power plant should better be in base-load operation, the construction of large-scale nuclear power base, would make the system load-control demands increase, which leads to more prominent problems. In order to avoid adding additional depth of peaking power operation and reducing the overall economic operation of power system, power grid should have the necessary means to load-control. Namely the construction of peaking units, such as pumped storage units or gas-fired units at about 5000MW. By analyzing and demonstration, large-scale nuclear power base must rely on large-scale power grid, particularly the support of UHV power grid in order to meet the demond of large-scale power transmission and electricity exchange, and also to ensure regional security of electricity supply.

<p>The recently completed $559M reconstruction of the Dolphin Expressway‐Palmetto Expressway Interchange in Miami, FL (USA) represents an excellent example of severe urban site constraints due to the amount of traffic, the proximity to a busy international airport and the surrounding urban landscape. This paper illustrates the solutions adopted by the design‐build team to deal with the challenges of this urban site. Further, it explains how they were integrated in various phases of the project which was completed over a five‐year span, and completed in 2016.</p><p>The main focus of this paper is the four precast segmental flyovers with a total length of 2.4 km, designed by FINLEY and erected over the existing traffic (400,000 vehicles that traveled this route daily) with the use of a launching gantry. Several key modifications were proposed to the Owner’s original concept of the bridges and as part of the framework of the design‐build procurement. The design choices were driven by the selected erection method, the intent to relieve the congested area of the intersection by using fewer piers and simpler construction details. Most notably, this includes the introduction of a superstructure haunch to achieve longer spans, design of post‐tensioning details suited for easy construction and special design of pier heads with provisions for balanced cantilever stability that eliminated the need of temporary falsework towers in the tight space of the intersection’s heart.</p><p>The project highlights the positive aspects of a design‐build method, the importance of teamwork among design‐build team members and how the proposed modifications added value on this complex project.</p>