Orangutan

The largest of the Asian primates, the orangutan, belongs to the Hominidae (or Great Apes) family whose members also include humans, chimpanzees, and gorillas.  While fossil records indicate that this primate once inhabited much of Southeast Asia, its current populations are restricted only to the islands of Borneo and Sumatra.  Moreover, recent genetic evidence has revealed that the Bornean orangutan (Pongo pygmaeus) is actually a different species from its Sumatran relative (Pongo abelii).  Additionally, three subspecies of Pongo pygmaeus (P. p. morio, P. p. pygmaeus, and the most common P. p. wurmbii) are recognized based on the mammal’s home range distributions
In terms of physical description, the Bornean and Sumatran orangutans exhibit a characteristic ape-like shape, shaggy reddish fur, and long powerful arms with strong, grasping hands and feet that enable individuals to gracefully traverse the forest canopy by brachiating and grabbing hold of nearby tree branches.  Both species also demonstrate similar sexual dimorphism.  Adult males are distinguished by their larger size, well-developed throat pouch, and flanges, known as cheek pads, on either side of the face.  Yet, there are subtle dissimilarities in body build, coat characteristics, and facial features that serve to differentiate one species from the other in addition to their geographic separation.
Although uniquely adapted for survival as the largest tree-dwelling mammal in the world, orangutan populations have been steadily declining in both range and numbers for many years. They are currently in danger of becoming extinct within the next few decades.  Humans have a long history of hunting this particular primate for various reasons including food, exhibition in zoos, or illegal pet trade, but the main threat to the orangutan’s continued existence derives from loss of habitat.  In the last half-century, close to 80% of orangutan territory has been exploited by illegal logging operations, gold mining, and conversion of pristine forests to permanent agricultural sites, in particular palm oil plantations.   Between 1997 and 1998, it is believed that around one-third of the island’s orangutan species subsequently perished following forest fires caused by slash and burn farming techniques in Borneo.
Because this primate inhabits densely forested regions, it is difficult to determine precise population sizes; however, estimates place the current number of Bornean orangutans at approximately 55,000.  Sumatran populations have fared much worse, declining as much as 50% during the 1990s, such that current censuses indicate only about 7,500 individuals remain.  Taking into account that both species have extremely slow reproductive cycles and require extensive home ranges to support their dietary needs, their populations have become highly vulnerable to excessive mortality. The population will require a long time to recover even if government-sponsored protective measures can be routinely instituted and sustained.
In their native environments, Bornean and Sumatran orangutans often display a semi-solitary social organization, which is quite uncommon among great apes.  Individuals usually travel alone or in small groups consisting of two females, their dependent young, and occasionally an adult male, although temporary travel bands and feeding aggregates have been observed when quantities of food are plentiful.  Generally, males and females come together only to mate, at which time dominant males become polygamous.  Although there is no distinct breeding season, females typically give birth only once every five to eight years due to the lengthy gestation period (of about nine months) and the prolonged maternal investment in offspring development.  In contrast, adult males can afford only sporadic parental care since their reproductive success largely depends on the formation and maintenance of dominance hierarchies with other males whose home ranges overlap with their own.
With regard to their daily activities, orangutans are diurnal and almost exclusively arboreal.  A typical routine begins with early morning foraging on fruit and other items such as leaves, insects and tree bark.  Afterward, there is midday rest, late afternoon travel, and early evening preparation of a nighttime nest.  These nests are normally constructed from branches and other vegetation obtained from the forest canopy, and they resemble platform-style beds situated 40 to 60 feet above ground.

Heavy metal

Pentahydrate copper sulfate crystal . Copper is an essential micronutrient, but also toxic to most organisms at high levels.

A heavy metal is any one of a number of elements that exhibit metallic properties, which includes transition metals lanthanides actinides as well as the metalloids Arsenic and Antimony. Typically the term refers to elements of atomic number 21 or higher (e.g. Scandium or above) The term heavy metal chiefly arose with discussions of pollutants discharged to the environment in the form of air, water or soil contaminants. While many heavy metals have considerable toxicity, others are considered not deemed to possess significant toxic properties, and, in fact, several of these elements including zinc, iron, copper, chromium and cobalt are necessary for metabolic function for a large class of organisms.
Although some heavy metals are essential micronutrients for animals, plants and many micro-organisms, depending on the route and dose, all heavy metals demonstrate toxic effects on living organisms via metabolic interference and mutagenesis. Animal health impacts range from reduction in fitness, to reproductive interference to carcinoma, with many exposures being lethal.

Definition

Manganese oxide-hydroxide, a monoclinic crystal. Source: Smithsonian Institute

There have been several schemes for designating heavy metals, based upon atomic number, toxicity or other factors; however, the usage of the term has centered on the treatment of certain metallic elements which have an impact upon plants or animals when discharged into the natural environment in relatively high concentrations. In terms of degree of interest, the chief heavy metals of note in the environmental science literature are lead, mercury, cadmium, chromium, copper, manganese, nickel, zinc, silver. Some schemes of classification for heavy metals exclude the lanthanides and actinides. The heavy metals are generally to consider all of the transition elements, eg. those elements with an incomplete d-shell.

Physical and chemical properties

Tetracarbonylhydrocobalt, a heavy metal ligand compound.

The heavy metals generally exhibit good electrical and thermal conductivity when in their pure form in many cases "heavy" refers literally to a metals specific gravity (ranging from 3.5-6 g/cm3), mass, and as indicated earlier, atomic number. The transition elements can manifest themselves as in varying chemical species or oxidation states;^[1] moreover, many transition metals can be bound to a variety of species or ligands. All of the transition metals have two or more oxidation states.

Essential for life

While copper is an essential micronutrient, it also can manifest in disease syndromes with tissue accumulation, as seen in this iris eye-ring anomaly. Source Herbert L.Fred and Hendrik Dijk

There are no elements in the lanthanide or actinide series that are essential to life; however, among the transition metals the following elements play a fundamental role in metabolic function for a vast array of organisms: vanadium, manganese, iron, cobalt, nickel, copper, zinc and molybdenum. Each of these, however, can produce adverse impacts if ingested at sufficiently high concentrations. The most widespread human deficiency is noted in zinc, for which over two billion humans, mostly in developing countries, suffer from inadequate amounts of zinc in their diet. Resulting effects include growth retardation and increased susceptiblity to infection, with a net outcome of a contributory cause of death in more than 800,000 children per year.^[2]

Heavy metals in plants

Plants have proven particularly effective for both bioremediation of metal contaminated sites and for studying the uptake, transport and toxicity of metals in general, and the following sections focus on heavy metals phenomena in plants.

Plant root uptake

The transport and cell wall diffusion theory of plant root uptake of heavy metals is fundamentally similar to processes governing other minerals in solution. Availability at the root surfaces is limited by diffusion of the metal cations (only molybdenum is taken up in anion form); by the interception of growing roots; and by mass transport of solute flowing toward the root, driven by evapotranspiration. Thus, in the case of rapid root uptake, a depletion zone of the heavy metal may form near the root uptake sites, unless evapotranspiration and root growth rate overwhelm the diffusion process.The actual crossing of the root membrane may occur by ionic diffusion, but in many cases may be aided by a protein or other biochemical transporter mediary.
A variety of factors influence the rate of uptake by plant roots. Obviously the solubility of the chemical species plays a dominant role; beyond that, pH has a relatively systematic effect, with higher pH levels facilitating uptake of all metals, including heavy metals. One of the chief reasons for this systematic bias is that hydrogen ions compete with metal cations at the root uptake sites.^[3] Again from a mechanism of competition at the root zone, there is also a general depression of heavy metal uptake in the presence of high concentrations of soil nutrients, e.g.calcium.  In the case of salinity variation, the results vary widely depending upon the precise species (or valence) of the heavy metal cation. Increased light levels are clearly correlated to higher root uptake of heavy metals.
There is a significant amount of filtering or rejection of unwanted heavy metals due to the architecture of the root tissues. Once the heavy metal ion has penetrated the outer root membrane, it is forced to navigate the crossing of the Casparian Strip, a waxy impregnated layer of the endodermis that forces all solute materials diffusing across the root epidermis to enter a before entering the xylem, which serves as a veritable freeway of solute transport driven by evapotranspiration. Thus each plant species has its own highly specialized filter mechanism to limit the inflow of harmful chemicals.
The presence of mycorriza (the result of a symbiotic relationship between plant roots and a fungus) inhibit the uptake of toxic heavy metals for some combinations of metal and fungal species. This phenomenon is thought to be due to the presence of certain peptides, organic acids and polyphosphate grains in the fungal mycelium (vegetative filaments.)
Efflux mechanisms also operate at the plant root surfaces to expel heavy metals from the plant; moreover, these efflux processes appear to be governed by ionic diffusion. These elimination processes seem to be very important in regulating the cellular concentrations of essential metals such as zinc.

Plant foliar uptake

Manganese lesions on cantaloupe leaves. Source: University of Delaware

Leaf surfaces can act as points of uptake for heavy metals, both by stomatal and cuticle pathways. Stomates allow passage of gaseous heavy metals, e.g. mercury, whereas cuticle intake is applicable to ionic forms of heavy metals. High relative humidity promotes cuticle intake, since those conditions create a swollen cuticle, subject to easiest penetration. There is a pronounced difference on cuticular uptake rate for different heavy metals. For example, copper, zinc and cadmium are found to be taken up at high rates by cuticles of many plants, whereas lead is transmitted in very low quantities.
As in the case of root tissue, leaves also have a reverse process of efflux. Remarkably some stomata have shown this to be a mechanism for eliminating ionic mercury, by conversion to gaseous form in the stomata and effluxing the resultant gas. A more common manifestation of this reverse or efflux process is the expulsion of heavy metal ions through the cuticle. The phenomenon is particularly important when acid rain is deposited on leaf surfaces. Then, due to high hydrion concentrations, there can be significant cation exchange with a result of expulsion of considerable amounts of heavy metals onto leaf surfaces, and eventual washing of the leaves by the precipitation itself.

Plant internal transport

Mouse ear syndrome leaf damage to River birch by excess nickel uptake. Source: Carl Rosen

Within the plant structure there is considerable variation in the mobility of heavy metals, depending on the plant species and the particular metal. For example, cadmium and zinc are much more mobile than copper or lead. Young plants are usually more efficient at internal transport of heavy metals, since the Casparian Strip is not well developed, such that the rejection filter in the root structure is less effective. In addition, young plants have a high shoot to root mass ratio, so that the upward movement of metals is governed more by root pressure and less by the transpiration process.^[4]

Plant toxicity

See main article: Absorption of toxicants

Wholesale ecological damage from zinc contaminated soils, Palmerton, Pennsylvania; low pH is a concomitant issue. Source: Keith Weller/USDA

Adverse impacts to plant metabolism appear at elevated concentrations of all heavy metals. These effects manifest in decrease in germination, increase in seedling mortality, inhibition of growth rates and reduction in reproductive capability. For the essential micronutrients, there is usually a threshold concentration, below which no adverse effects are observed, but with elevation of levels above the threshold, monotonically increasing toxic impacts are evinced.
As an example, studies of copper and cadmium exposure indicated no adverse effects for cation concentrations of up to .01 mg/liter; however, with increasing concentrations in the root zone, there was a steady decline in germination rates.^[5] Cadmium was somewhat more toxic than copper in the cases analyzed; moreover, the combined effects of copper and cadmium provided a negative synergistic effect on seed germination.
Plants have proved to be such reliable indicators of heavy metal toxicity that they have demonstrated clear advantages over sacrificing fauna in laboratory testing. For example, many of the effect relationships (e.g. mortality versus concentration) are not only monotonic, but quite linear; in addition, use of common duckweed (Lemna minor) for toxicity assays of water pollution stemming from heavy metal concentrations showed greater sensitivity to metals by a factor of eight relative to published 96 hour fish bioassays.
The mechanisms of heavy metal toxicity can be traced to metabolic interferences related to enzyme synthesis or DNA replication itself. Specific interference phenomena include down-regulation of essential protein synthesis appurtenant to enzyme production, but also include oxidative damage of nucleobases and mutagenesis phenomena. Mutageneses have been observed in both plants and animals for all of the following heavy metals: cadmium, copper, chromium, nickel, lead, mercury, platinum and zinc.^[6]

Serpentine soils

California pitcher plant growing on serpentine soils rich in nickel, chromium and certain other heavy metals. Source: Sydney Carothers/U.S.Forest Service

Serpentine soils are defined as unusual soil types which are rich in such heavy metals as nickel and chromium and deficient in calcium. Correspondingly plant associations thrive on these soils which are specially adapted to these soil mineral conditions. While serpentine soils are often noted for their plant associations which are rich in rare wildflowers, there are numerous shrubs and trees that have emerged as specialists to these soils; the California endemic tree Leather Oak is an example of such a larger plant.  In fact, serpentine soils are the loci of highly restricted range species and many rare species of not only plants, but insects and even higher fauna.^[7]

Heavy metals in animals

Most heavy metals, even those essential for life, have thresholds above which toxic effects are evidenced. Pathways of entry for animal exposure include respiratory, ingestion and dermal contact. Effects of elevated heavy metal concentration vary, and may  include fitness reduction, impacts to reproductive success and production of carcinomas.

Pathways of entry

Respiratory intake may occur in the form of atomic or molecular gases, an example being mercury vapor; however a more common form of respiratory intake is heavy metal attachment to particulate matter. This circumstance is common in many industrial and energy generation applications, particularly from combustion of coal and from metal refining. The most severe health risk is posed when the particulate matter is extremely fine; in these instances, the particulate matter can penetrate deeply into the lungs, with increasing risk of long residence lodging. A special risk is posed when the heavy metal is also a radioactive substance; this case is notable for many forms of tobacco smoking, where traces of uranium are present in the phosphate rock fertilizers commonly used in tobacco growing.
Ingestion of heavy metals is a significant pathway of exposure. Particularly common pathways are ingestion of water contaminated by heavy metals from industrial wastewater discharge, and ingestion by eating higher level predators, who have concentrated heavy metals from successive food chain predation levels. High mercury levels in fish are common examples of this phenomenon. Typically the concentration of heavy metals in predators becomes more elevated at higher rungs of the food chain. Ingestion of metal contaminated plants is also a significant pathway of entry
Dermal exposure is generally a lower risk pathway, generally more relevant in industrial settings, where workers are cautioned to wash down exposed areas after work shifts. The dermal pathway is potentially significant for situations where heavy industrial plants are sited near residential uses in developing countries that lack the land use controls and emission controls of Western Countries. There is also a great deal of interest in potential exposure to consumers using sunscreen products based on nanoized titanium dioxide and zinc.

Transport and storage within animals

Once within the animal organism, there are a myriad of internal transport, storage and metabolic interference effects. At the transport level, one of the most significant transitions is migration from the lung tissue to bloodstream; for example, almost forty percent of inhaled lead enters the circulatory system. Subsequent to entering the bloodstream, there are many intermediate storage areas, the longest residence time being in bone. Again, using lead as an example, half life storage in human bone is approximately 25 years.
Specific organs are subject to elevated sensitivity to certain heavy metals. For example the brain is sensitive to lead poisoning, and there is widespread occurrence of permanent reduction of brain performance, particularly for children exposed to high levels of lead in the environment.

Metabolic impacts on animals

There are a vast variety of metabolic impacts of heavy metals upon animals.^[8] Some of the chief effects are enzyme inhibition, immune system degradation, neuron signal interference and organ specific degradation. One of the fundamental issues in cell metabolic interference is the ability of some heavy metals to mimic other metals essential in enzymatic processes. For example lead often displaces zinc or calcium in enzyme processes; these effects can lead to minor impacts such as fitness reduction ranging to lethal impact for some very high exposure. 
An example of organ failure effects is from hexavalent chromium which exerts acute oral toxicity for dosages as low as 50  µg/kg. The high toxicity of hexavalent chromium is based upon the strong oxidative effects of this metal. Subsequent to bloodstream transport hexavalent chromium impairs the liver, kidney and blood cells via oxidation, with high concentrations of chromium leading to complete shutdown of renal or liver organs.

Global Challenges/Chemistry Solutions

Global Challenges/Chemistry Solutions is a series of podcasts describing some of the 21st century's most daunting problems, and how cutting-edge research in chemistry matters in the quest for solutions. Global Challenges is the centerpiece in an alliance on sustainability between ACS and the Royal Society of Chemistry. Global Challenges is a sweeping panorama of global challenges that includes dilemmas such as providing a hungry, thirsty world with ample supplies of safe food and clean water; developing alternatives to petroleum to fuel society; preserving the environment and assuring a sustainable future for our children and improving human health. During the 2011 global celebration of the International Year of Chemistry (IYC), Global Challenges/Chemistry Solutions also is focusing on the main themes of IYC — health, environment, energy and materials.

An especially interesting component of this series relates to "Household washing machines are a source of potentially harmful ocean microplastic pollution":

For more entertaining, informative science videos and podcasts from the ACS Office of Public Affairs, view Prized Science, Spellbound, Science Elements and Global Challenges/Chemistry Solutions.
The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 163,000 members, ACS is the world's largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

Ecoregions of Utah

The Ecoregions of Utah comprise a diverse set of plant communities and geomorphic provinces. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. Ecoregions are directly applicable to the immediate needs of state agencies, including the development of biological criteria and water quality standards and the establishment of management goals for nonpoint-source pollution. They are also relevant to integrated ecosystem management, an ultimate goal of most federal and state resource management agencies.

The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity (Wiken 1986; Omernik 1987, 1995). These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 52 regions (Commission for Environmental Cooperation Working Group 1997). At level III, the continental United States contains 104 ecoregions and the conterminous United States has 84 ecoregions (United States Environmental Protection Agency [USEPA] 2000). Level IV is a further subdivision of level III ecoregions. Explanations of the methods used to define the USEPA’s ecoregions are given in Omernik (1995), Griffith and others (1994), and Gallant and others (1989).

Utah is made up of arid deserts and canyonlands, salt flats, wetlands, semiarid shrublands, irrigated valleys, woodlands, forested mountains, and glaciated peaks. Ecological diversity is enormous. There are 7 level III ecoregions and 37 level IV ecoregions in Utah and most continue into ecologically similar parts of adjacent states. The level III and IV ecoregion map on this poster was compiled at a scale of 1:250,000 and depicts revisions and subdivisions of earlier level III ecoregions that were originally compiled at a smaller scale (USEPA 2000; Omernik 1987). This poster is part of a collaborative project primarily between USEPA Region VIII, USEPA National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), Utah Department of Environmental Quality, Utah Division of Wildlife Resources, Utah Department of Natural Resources, United States Department of Agriculture-Forest Service (USFS), United States Department of Agriculture-Natural Resources Conservation Service (NRCS), United States Department of the Interior-Bureau of Land Management (BLM), and United States Department of the Interior-Geological Survey (USGS)-Earth Resources Observation Systems (EROS) Data Center.

The project is associated with an interagency effort to develop a common framework of ecological regions. Reaching that objective requires recognition of the differences in the conceptual approaches and mapping methodologies applied to develop the most common ecoregion-type frameworks, including those developed by the USFS (Bailey and others, 1994), the USEPA (Omernik 1987, 1995), and the NRCS (U.S. Department of Agriculture-Soil Conservation Service, 1981). As each of these frameworks is further refined, their differences are becoming less discernible. Regional collaborative projects such as this one in Utah, where agreement has been reached among multiple resource management agencies, is a step toward attaining consensus and consistency in ecoregion frameworks for the entire nation.

The Integrated Farm System Model

  

With tighter profit margins and increasing environmental constraints, strategic planning of farm production systems is becoming both more important and more difficult. This is especially true for dairy and beef production. Livestock production is complex with a number of interacting processes that include crop and pasture production, crop harvest, feed storage, grazing, feeding, and manure handling. Computer simulation provides a useful procedure for integrating these processes to predict the long-term performance, environmental impact, and economics of production systems.

Development of a simulation model of the dairy forage system began in the early 1980’s. The model, known as the Dairy Forage System Model or DAFOSYM, linked alfalfa and corn production models with a dairy animal intake model to predict feed production and disappearance on the farm. This model was expanded with additional components for simulating feed storage and animal performance. Manure handling, tillage, and planting operations were then added to extend the model to a simulation of the full dairy farm. The dairy farm model was broadened further by adding components for simulating grass, small grain, and soybean growth, harvest, and storage. Through a major revision, a beef animal component was added along with a crop farm option (no animals) to form the Integrated Farm System Model or IFSM. This model has continued to grow as components were added to simulate environmental impacts including ammonia volatilization, nitrate leaching, phosphorus runoff, and greenhouse gas emissions.

Unlike most farm models, IFSM simulates all major farm components on a process level. This enables the integration and linking of components in a manner that adequately represents the major interactions among the many biological and physical processes on the farm. This provides a robust research and teaching tool for exploring the whole farm impact of changes in management and technology. Process level simulation remains an important goal as additional components are developed and added.

In an IFSM simulation, crop production, feed use, and the return of manure nutrients back to the land are simulated over many years of weather. Growth and development of alfalfa, grass, corn, soybean, and small grain crops are predicted on a daily time step based upon soil water and N availability, ambient temperature, and solar radiation. Performance and resource use in manure handling, tillage, planting, and harvest operations are functions of the size and type of machines used and daily weather. Field drying rate, harvest losses, and nutritive changes in crops are related to the weather, crop conditions, and machinery operations used. Losses and nutritive changes during storage are influenced by the characteristics of the harvested crop and the type and size of storage facility used.

Feed allocation and animal response are related to the nutritive value of available feeds and the nutrient requirements of up to six animal groups making up either dairy or beef herds. Diets for each group are formulated using a cost-minimizing linear programming approach, which makes the best use of homegrown feeds and purchased supplements. Protein and energy requirements are determined for each animal group based upon the characteristics of the average animal in the group. One or two protein supplements are used to balance rations. These can include both high and low rumen degradable protein feeds. Feed characteristics can be defined to describe essentially any supplement of each type including blended feeds. Supplemental P and K fed, if needed, is the difference between the requirement of each animal group and the sum of that contained in the feeds consumed.

Nutrient flows through the farm are modeled to predict potential nutrient accumulation in the soil and loss to the environment. The quantity and nutrient content of the manure produced is a function of the quantity and nutrient content of the feeds consumed. Nitrogen volatilization occurs in the barn, during storage, following field application, and during grazing. Denitrification and leaching losses from the soil are related to the rate of moisture movement and drainage from the soil profile as influenced by soil properties, rainfall, and the amount and timing of manure and fertilizer applications. Erosion of sediment is predicted as a function of daily runoff depth, peak runoff rate, field area, soil erodibility, slope, and soil cover. Phosphorus transformation and movement is simulated among surface and subsurface soil pools of organic and inorganic P. Edge-of-field runoff losses of sediment-bound P and soluble P are predicted as influenced by manure and tillage management as well as daily soil and weather conditions. Greenhouse gas emissions of carbon dioxide, methane, and nitrous oxide are estimated for all sources and sink including crop production, fuel combustion, the animals, the barn floor, and manure storage.  Following the prediction of losses, whole-farm balances of N, P, K and C are determined as the sum of all nutrient imports in feed, fertilizer, deposition, and legume fixation minus the exports in milk, excess feed, animals, manure, and losses leaving the farm.

Simulated performance is used to determine production costs, incomes, and economic return for each year of weather. A whole-farm budget is used, which includes fixed and variable production costs. Annual fixed costs for equipment and structures are the product of their initial cost and a capital recovery factor where this factor is a function of an assigned economic life and real interest or discount rate. The resulting annual fixed costs are summed with predicted annual expenditures for labor, resources, and products used to obtain a total production cost. Labor cost accounts for all field, feeding, milking, and animal handling operations including charges for unpaid operator labor. This total cost is subtracted from the total income received for milk, animal, and excess feed sales to determine a net return to the herd and management.

By comparing simulation results for different production systems, the effects of system differences are determined, including resource use, production efficiency, environmental impact, production costs, and net return. Production systems are simulated over a 25 year sample of recent historical weather. All farm parameters, including prices, are held constant throughout the simulation so that the only source of variation among years is the effect of weather. Distribution of the annual values obtained describes possible performance outcomes as weather varies. Inter-year dynamics are not considered; initial conditions such as soil nutrient concentrations and feed inventories are reset each year. Therefore, the simulated data indicate the range of variation in economic and environmental performance that can occur given the variation in weather at the farm location, i.e. the distribution of simulated annual values indicates weather-related risk experienced by the simulated production system. A wide distribution in annual values implies a greater degree of risk.

The Integrated Farm System Model functions on all of the major Windows operating systems. Input information is supplied to the program through three parameter files. The farm parameter file contains data describing the farm such as crop areas, soil type, equipment and structures used, numbers of animals at various ages, harvest, tillage, and manure handling strategies, and prices for various farm inputs and outputs. The machinery file includes parameters for each machine available for use on a simulated farm. These parameters include machine size, initial cost, operating parameters, and repair factors. Most farm and machinery parameters are modified quickly and conveniently through dialog boxes in the user interface of the program. Many of these files can be created to store parameters for different farms and machinery sets for later use in other simulations. The weather file contains daily weather data for many years at a specific location. The daily data include the date, incident solar radiation, maximum and minimum temperatures, and total precipitation.

Simulation output is available in four files, which contain summary tables, report tables, optional tables, and parameter tables. The summary tables provide average performance, environmental impact, costs, and returns for the years simulated. These values consist of crop yields, feeds produced, feeds bought and sold, manure produced, nutrient losses to the environment, production costs, income from products sold, and the net return or profitability of the farm. Values are provided for the average and standard deviation of each over all simulated years. The report tables provide extensive output information including all the data given in the summary tables. In these tables, values are given for each simulated year of weather as well as the mean and variance over all simulated years. Optional tables are available for a closer inspection of how the components of the full simulation are functioning. These tables include very detailed data, often on a daily basis. Parameter tables summarize the input parameters specified for a given simulation. These tables provide a convenient method of documenting the parameter settings used for a simulation.

Nile River

Nile River is the longest river in the world and so named proportion to the Greek term Neilos is of the most prolific rivers in the Arab world where it is located on the continent of Africa and flows to the north, also it has two branches Riassn Mgvean him the White Nile in the east of the continent and Blue Nile in Atheobaahit that this branches constitute the western wing of the crack of the African east, which in turn constitutes the southern part of Africa of the Great Rift Valley so that the stems of the White Nile in the Great Lakes region of Central Africa and then being the river north of Tanzania to Lake Victoria, which is the lake from the main sources nourishing of the Nile River which is the third of the Great Lakes and Lake Victoria to Uganda and then to southern Sudan, while the main section II of the Nile River, but it is the Blue Nile, which begins at Lake Tana in Ethiopia and then going to the Sudan from the southeast and then combine the two rivers in the capital of Sudan (Khartoum ) The Nile River length is (6650 km) ((4132 miles as the Nile River passes ten African countries, called the Nile Basin countries Name They Sudan, Egypt, Kenya, Rwanda, Tanzania, Uganda and Athubaa and Congo Alimoukratih, Burundi, southern Sudan and Eritrea as an observer so that the Nile Basin covers an area of 3.4 million economic importance of the countries through which the Nile River, there are many of the economic Values ​​that are beneficial to the Nile Basin countries, because the Nile River is the only river which runs from the south to the north and the reason for this is the tendency of the land problem with diversified geographically unique, starting from the highlands in the south, at least this rise in the northern regions which contain spacious plains. River Nile is a great importance in the economy of countries that passes from its territory, called the Nile Basin countries, particularly in agriculture, where farmers depend on all Nile Basin countries on the Nile River water to irrigate agricultural Mhaslehm Among the most famous of these crops: cotton, wheat, sugar cane, palm, legumes, citrus fruits. It has great importance in the field of fishing, where many fishermen depends on Alasmalk in the Nile River as the fish is the dish favorite peoples of the Nile Basin countries and the most important aquaculture in the Nile River, the most important of Nile crocodile in addition to its importance in the field of agriculture and fishing as well as to display the field of private tourism in Sudan and Egypt, countries where one kind of tourism in those countries which are called the "Nile tourism", where sail Filokh tourists and visitors to that country in Sudan carrier sailing from between the two dams third and fourth in the north of Sudan and, between Juba and Kosti in southern Sudan and Giza, Minya, Sohag and Qena and Aswan in Egypt. A historical overview of the Nile was the Nile River Almtma for many of the colonial powers in the nineteenth century, the proportion of economic importance posed by the Nile River has dominated the European countries of the Nile Basin countries in that period; Britain was controlled by Egypt and the Sudan, Uganda and Kenya, it was Germany captures Tanzania, Rwanda and Burundi. Belgium was in control of the DRC, which was known at the time as Zaire. Having obtained the First World War general ((1914-1918 worked the German Empire on the zoning between Britain and Belgium; were Tanzania from Britain's share was Rwanda and Burundi share of Belgium, while Ethiopia remained an independent state. In the fifties ended Britain control of the Sudan and Egypt worked to sign Nile River agreement in 1959 to divide the waters of the Nile, but most of the Nile Basin countries rejected this division unjust and they see from the days of colonial expansion. Summary is the Nile River from the world's longest river, where is the oldest in length and features profusely waters and was considered the heaviest rivers in the Arab world, and is located River Nile in the State of Egypt, which lies on the African continent and that the length of the river is 6650 km It is also the advantage of being passed by 10 African countries have called on countries that pass the Nile River through them African Nile Basin countries. The River Nile considerable economic and interest on the importance of Nile Basin countries, as well as to distinguish it from what has distinctive geographic diversity, and the major interest in the field of agriculture, where farmers rely very heavily on the waters of the Nile and especially the Nile Basin countries.

The Dead Sea

The Dead Sea is located in the south-west of the Jordanian capital Amman, but we will talk in this article about the whereabouts of the Dead Sea and geographical location specifically and then we'll addressing the names of ancient and modern Dead Sea and the reasons for the Dead Sea, a label with that name, and we'll talk about the most important characteristics that distinguish them and the most important natural and tourism features in it and we will look to talk about the most important benefits derived and acquired from the Dead Sea waters of the Dead Sea is a lake surface is the lowest region in the world, is located in the south-west of the Jordanian capital Amman, is located in the central area between Jordan and Palestine is surrounded by several natural landmarks, it is the eastern side of the mountains of Balqa and plateaus Salt Heights are located, and the western side Palestine Heights is especially Jerusalem Heights, and reaches the Dead Sea size to 946 square kilometers, while the Dead Sea length amounts to 80 kilometers and width up to 15 kilometers As For feeding the Dead Sea it goes back to the Jordan River as its water is poured in it and a blue Ma'in stream and river all the positive feed the Dead Sea and is concentrated in the Dead Sea water high in potassium, magnesium, chloride and bromide salts and many other minerals. Titles, which was launched on the Dead Sea and the reason named by: so-called Dead Sea old Lake Lot and this is due, because the Prophet Lot sent to his people of Sodom and Gomorrah in the same area, and the Dead Sea was named "Dead Sea" as a result of the lack of life in which there is no living organisms exist the characteristics that are unique to the Dead Sea, lacking life in the Dead Sea as a result of high salinity in it, and the Dead Sea is characterized in that it is the most low-lying area in the world and the Dead Sea cult strongly characterized by heat in the summer and warmly faces in the winter. Dead Sea of ​​its properties purity of the sun's rays which are located in the Dead Sea area hot water enjoyed the visitors as the Dead Sea water is rich in potassium, sodium, magnesium, bromine, manganese, and extracted from lotions beauty used the Dead Sea water contains the user mud in the treatment of monuments skin diseases and natural tourist Almlamj in the Dead Sea, located in the Dead Sea area and restrooms are popular parks, beaches, hotels and restaurants in abundance.

 South Beach: one of the most beautiful places quieter and are derived from spirituality is a stunning nature.

 Hot sea water: one of the most attractive places of the Dead Sea salts are rich in magnesium, sodium, potassium and other minerals chloride, Valsuah enjoy them through the float on their backs to penetrate metal in their bodies.

 Oman Beach tourism: abound in Amman Beach tourism necessary for swimming pools are available a private dressing and many places for hiking and worked for many concerts in which rooms, where there is also a football field and basketball court, volleyball and spread Ulkipteriaat in the entire hotel and there are also many car parks and fountains beautiful waters and numerous seats

• resorts: Kalmariot and Alkmbenski and Mövenpick all of which are equipped with all the needs of hotels and health centers are used to treat skin diseases and is used for medical operations cosmetic and health resort, the Dead Sea gives the patients the opportunity to treat skin diseases Almokhtlvhkalsdwih