المناصب التي تقلدها

• 1958: ملحق بوزارة الخارجية المصرية.
• 1958 ـ 1972 : عمل بالعديد من الإدارات والبعثات المصرية ومنها البعثة المصرية لدى الأمم المتحدة
• 1974 ـ 1977 : مستشار لدى وزير الخارجية المصري
• 1977-1981 :1986-1990 : مدير إدارة الهيئات الدولية بوزارة الخارجية المصرية
• 1981-1983 : مندوب مناوب لمصر لدى الأمم المتحدة بنيويورك
• 1983-1986 : سفير مصر في الهند
• 1990-1991 : مندوبا دائما لمصر لدى الأمم المتحدة بنيويورك
• 1991-2001 : وزيرا للخارجية المصرية
• 2001 : أمينا عاما لجامعة الدول العربية
• 2003 : عضو في اللجنة الرفيعة المستوى التابعة للأمم المتحدة المعنية بالتهديدات والتحديات والتغيير المتعلقة بالسلم والأمن الدوليين

الأوسمة والجوائز

• حاصل على وشاح النيل من جمهورية مصر العربية في مايو 2001
• حاصل على وشاح النيلين من جمهورية السودان في يونيو 2001
• حصل على عدة اوسمة رفيعة المستوى من كل من الدول التالية : الاكوادور - البرازيل - الأرجنتين - ألمانيا

أدخلوا مصر إن شاء الله آمنين...صدق الله العظيم
 

Bird migration
 

The typical image of migration is of northern landbirds, such as swallows and birds of prey, making long flights to the tropics. Many northern-breeding ducks, geese and swans are also long-distance migrants, but need only to move from their Arctic breeding grounds far enough south to escape frozen waters. Most Holarctic wildfowl species remain in the Northern Hemisphere, but in countries with milder climates. For example, the pink-footed goose migrates from Iceland to Britain and neighbouring countries. Migratory routes and wintering grounds are traditional and learned by young during their first migration with their parents. Some ducks, such as the Garganey, move completely or partially into the tropics.
The same considerations about barriers and detours that apply to long-distance land-bird migration apply to water birds, but in reverse: a large area of land without bodies of water that offer feeding sites is a barrier to a water bird. Open sea may also be a barrier to a bird that feeds in coastal waters. Detours avoiding such barriers are observed: for example, Brent Geese migrating from the Taymyr Peninsula to the Wadden Sea travel via the White Sea coast and the Baltic Sea rather than directly across the Arctic Ocean and northern Scandinavia.
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Bar-tailed Godwit


A similar situation occurs with waders (called "shorebirds" in North America). Many species, such as Dunlin and Western Sandpiper, undertake long movements from their Arctic breeding grounds to warmer locations in the same hemisphere, but others such as Semipalmated Sandpiper travel longer distances to the tropics in the Southern Hemisphere. Like the large and powerful wildfowl, the waders are strong fliers. This means that birds wintering in temperate regions have the capacity to make further shorter movements in the event of particularly inclement weather.
For some species of waders, migration success depends on the availability of certain key food resources at stopover points along the migration route. This gives the migrants an opportunity to "refuel" for the next leg of the voyage. Some examples of important stopover locations are the Bay of Fundy and Delaware Bay.
Some Bar-tailed Godwits have the longest known non-stop flight of any migrant, flying 11,000 km from Alaska to their New Zealand non-breeding areas.[17] Prior to migration, 55 percent of their bodyweight is stored fat to fuel this uninterrupted journey.
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Arctic Terns


Seabird migration is similar in pattern to those of the waders and waterfowl. Some, such as the Black Guillemot and some gulls, are quite sedentary; others, such as most terns and auks breeding in the temperate northern hemisphere, move varying distances south in the northern winter. The Arctic Tern has the longest-distance migration of any bird, and sees more daylight than any other, moving from its Arctic breeding grounds to the Antarctic non-breeding areas. One Arctic Tern, ringed (banded) as a chick on the Farne Islands off the British east coast, reached Melbourne, Australia in just three months from fledging, a sea journey of over 22,000 km (14,000 miles). A few seabirds, such as Wilson's Petrel and Great Shearwater, breed in the southern hemisphere and migrate north in the southern winter. Seabirds have the additional advantage of being able to feed during migration over open waters.
The most pelagic species, mainly in the 'tubenose' order Procellariiformes, are great wanderers, and the albatrosses of the southern oceans may circle the globe as they ride the "roaring forties" outside the breeding season. The tubenoses spread widely over large areas of open ocean, but congregate when food becomes available. Many are also among the longest-distance migrants; Sooty Shearwaters nesting on the Falkland Islands migrate 14,000 km (9,000 miles) between the breeding colony and the North Atlantic Ocean off Norway. Some Manx Shearwaters do this same journey in reverse. As they are long-lived birds, they may cover enormous distances during their lives; one record-breaking Manx Shearwater is calculated to have flown 8 million km (5 million miles) during its over-50 year lifespan.
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Griffon Vulture soaring


Some large broad-winged birds rely on thermal columns of rising hot air to enable them to soar. These include many birds of prey such as vultures, eagles, and buzzards, but also storks. These birds migrate in the daytime. Migratory species in these groups have great difficulty crossing large bodies of water, since thermals only form over land, and these birds cannot maintain active flight for long distances. The Mediterranean and other seas present a major obstacle to soaring birds, which must cross at the narrowest points. Massive numbers of large raptors and storks pass through areas such as Gibraltar, Falsterbo, and the Bosphorus at migration times. More common species, such as the Honey Buzzard, can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can also cause funnelling, particularly of large diurnal migrants. This is a notable factor in the Central American migratory bottleneck.
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Ruby-throated Hummingbird


Many of the smaller insectivorous birds including the warblers, hummingbirds and flycatcher[disambiguation needed]s migrate large distances, usually at night. They land in the morning and may feed for a few days before resuming their migration. The birds are referred to as passage migrants in the regions where they occur for short durations between the origin and destination.[18]
Nocturnal migrants minimize predation, avoid overheating, and feed during the day.[16] One cost of nocturnal migration is the loss of sleep. Migrants may be able to alter their quality of sleep to compensate for the loss.[19]
Short-distance and altitudinal migration

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Cedar Waxwing


Many long-distance migrants appear to be genetically programmed to respond to changing day length. Species that move short distances, however, may not need such a timing mechanism, and may move in response to local weather conditions.
Thus mountain and moorland breeders, such as Wallcreeper and White-throated Dipper, may move only altitudinally to escape the cold higher ground. Other species such as Merlin and Skylark will move further to the coast or to a more southerly region. Species like the Chaffinch are not migratory in Britain, but will move south or to Ireland in very cold weather.
Short-distance passerine migrants have two evolutionary origins. Those that have long-distance migrants in the same family, such as the Chiffchaff, are species of southern hemisphere origins that have progressively shortened their return migration to stay in the northern hemisphere.
Species that have no long-distance migratory relatives, such as the waxwings, are effectively moving in response to winter weather, rather than enhanced breeding opportunities.
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Woodland Kingfisher


In the tropics there is little variation in the length of day throughout the year, and it is always warm enough for a food supply (although because of competition, there may not be enough food for every bird). Migration within the tropics has been far less studied than in the temperate zones. It was once assumed that tropical birds were mostly sedentary; however, altitudinal migration and other within-tropics movements appear to be surprisingly common (citation needed). Many tropical regions have wet and dry seasons, inducing some birds to migrate or wander widely to find food. Indeed, the monsoons of India are preceded by the arrival of the Jacobin Cuckoo, the "harbinger of the monsoon". Other examples include the Woodland Kingfisher of west Africa and many Australian birds.
There are a few species, notably cuckoos, which are genuine long-distance migrants within the tropics. An example is the Lesser Cuckoo, which breeds in India and spends the non-breeding season in Africa. Such examples help make the case that food supplies, not weather per se, drive migration patterns.
Altitudinal migration is common on mountains worldwide, such as in the Himalayas and the Andes. Quite often, altitudinal migration is combined with distance migration; for example, the Himalayan Kashmir Flycatcher and Pied Thrush both move as far south as the highlands of Sri Lanka. Altitudinal migration may even be important to birds living on relatively small islands, such as the Hawaiian Islands, which have high mountains.

Leaf
 

Leaf

From Wikipedia, the free encyclopedia


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The leaves of a Beech tree


In botany, a leaf is an above-ground plant organ specialized for the process of photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin. As an evolutionary trait, the flatness of leaves works to expose the chloroplasts to more light and to increase the absorption of carbon dioxide at the expense of water loss. In the Devonian period, when carbon dioxide concentration was at several times its present value, plants did not have leaves or flat stems. Many bryophytes have flat, photosynthetic organs, but these are not true leaves. Neither are the microphylls of lycophytes. The leaves of ferns, gymnosperms, and angiosperms are variously referred to as macrophyll, megaphylls, or euphylls.
Leaves are also the sites in most plants where transpiration and guttation take place. Leaves can store food and water, and are modified in some plants for other purposes. The comparable structures of ferns are correctly referred to as fronds. Furthermore, leaves are prominent in the human diet as leaf vegetables.




Anatomy

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Leaf in autumn.


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Cross section of a leaf


A structurally complete leaf of an angiosperm consists of a petiole (leaf stalk), a lamina (leaf blade), and stipules (small processes located to either side of the base of the petiole). The petiole attaches to the stem at a point called the "leaf axil." Not every species produces leaves with all of the aforementioned structural components. In certain species, paired stipules are not obvious or are absent altogether. A petiole may be absent, or the blade may not be laminar (flattened). The tremendous variety shown in leaf structure (anatomy) from species to species is presented in detail below under Leaf morphology. Periodically (i.e. seasonally, during the autumn), deciduous trees shed their leaves. These leaves then decompose into the soil.
A leaf is considered a plant organ and typically consists of the following tissues:

1. An epidermis that covers the upper and lower surfaces
2. An interior chlorenchyma called the mesophyll
3. An arrangement of veins (the vascular tissue)

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Epidermis

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Epidermal cells


The epidermis is the outer layer of cells covering the leaf. It forms the boundary separating the plant's inner cells from the external world. The epidermis serves several functions: protection against water loss by way of transpiration, regulation of gas exchange, secretion of metabolic compounds, and (in some species) absorption of water. Most leaves show dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions.
The epidermis is usually transparent (epidermal cells lack chloroplasts) and coated on the outer side with a waxy cuticle that prevents water loss. The cuticle is in some cases thinner on the lower epidermis than on the upper epidermis, and is thicker on leaves from dry climates as compared with those from wet climates.
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SEM image of Nicotiana alata leaf's epidermis, showing trichomes (hair-like appendages) and stomata (eye-shaped slits, visible at full resolution).


The epidermis tissue includes several differentiated cell types: epidermal cells, guard cells, subsidiary cells, and epidermal hairs (trichomes). The epidermal cells are the most numerous, largest, and least specialized. These are typically more elongated in the leaves of monocots than in those of dicots.
The epidermis is covered with pores called stomata, part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The stoma complex regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Typically, the stomata are more numerous over the abaxial (lower) epidermis than the adaxial (upper) epidermis.
Mesophyll

Most of the interior of the leaf between the upper and lower layers of epidermis is a parenchyma (ground tissue) or chlorenchyma tissue called the mesophyll (Greek for "middle leaf"). This assimilation tissue is the primary location of photosynthesis in the plant. The products of photosynthesis are called "assimilates".
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Palisade cells


In ferns and most flowering plants the mesophyll is divided into two layers:

• An upper palisade layer of tightly packed, vertically elongated cells, one to two cells thick, directly beneath the adaxial epidermis. Its cells contain many more chloroplasts than the spongy layer. These long cylindrical cells are regularly arranged in one to five rows. Cylindrical cells, with the chloroplasts close to the walls of the cell, can take optimal advantage of light. The slight separation of the cells provides maximum absorption of carbon dioxide. This separation must be minimal to afford capillary action for water distribution. In order to adapt to their different environment (such as sun or shade), plants had to adapt this structure to obtain optimal result. Sun leaves have a multi-layered palisade layer, while shade leaves or older leaves closer to the soil, are single-layered.

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Spongy cells

• Beneath the palisade layer is the spongy layer. The cells of the spongy layer are more rounded and not so tightly packed. There are large intercellular air spaces. These cells contain fewer chloroplasts than those of the palisade layer.

The pores or stomata of the epidermis open into substomatal chambers, connecting to air spaces between the spongy layer cells.
These two different layers of the mesophyll are absent in many aquatic and marsh plants. Even an epidermis and a mesophyll may be lacking. Instead for their gaseous exchanges they use a homogeneous aerenchyma (thin-walled cells separated by large gas-filled spaces). Their stomata are situated at the upper surface.
Leaves are normally green in color, which comes from chlorophyll found in plastids in the chlorenchyma cells. Plants that lack chlorophyll cannot photosynthesize.
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Leaves shifting color in fall


Leaves in temperate, boreal, and seasonally dry zones may be seasonally deciduous (falling off or dying for the inclement season). This mechanism to shed leaves is called abscission. After the leaf is shed, a leaf scar develops on the twig. In cold autumns they sometimes change color, and turn yellow, bright orange or red as various accessory pigments (carotenoids and xanthophylls) are revealed when the tree responds to cold and reduced sunlight by curtailing chlorophyll production. Red anthocyanin pigments are now thought to be produced in the leaf as it dies, possibly to mask the yellow hue left when the chlorophyll is lost - yellow leaves appear to attract herbivores such as aphids.[1]
Veins

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Vein skeleton of a Hydrangea leaf


The veins are the vascular tissue of the leaf and are located in the spongy layer of the mesophyll. They are typical examples of pattern formation through ramification. The pattern of the veins is called venation.
The veins are made up of:

• Xylem: tubes that brings water and minerals from the roots into the leaf.
• Phloem: tubes that usually move sap, with dissolved sucrose, produced by photosynthesis in the leaf, out of the leaf.

The xylem typically lies over the phloem. Both are embedded in a dense parenchyma tissue, called "pith", with usually some structural collenchyma tissue present.
Morphology

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The Citrus leaf is identified by the pores and pigments, as well as the margins.


External leaf characteristics (such as shape, margin, hairs, etc.) are important for identifying plant species, and botanists have developed a rich terminology for describing leaf characteristics. These structures are a part of what makes leaves determinant; they grow and achieve a specific pattern and shape, then stop. Other plant parts like stems or roots are non-determinant, and will usually continue to grow as long as they have the resources to do so.
Classification of leaves can occur through many different designative schema, and the type of leaf is usually characteristic of a species, although some species produce more than one type of leaf. The longest type of leaf is a leaf from palm trees, measuring at nine feet long. The terminology associated with the description of leaf morphology is presented, in illustrated form, at Wikibooks.
Basic types


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Leaves of the White Spruce (Picea glauca) are needle-shaped and their arrangement is spiral

• Ferns have fronds
• Conifer leaves are typically needle-, awl-, or scale-shaped
• Angiosperm (flowering plant) leaves: the standard form includes stipules, a petiole, and a lamina
• Lycophytes have microphyll leaves.
• Sheath leaves (type found in most grasses)
• Other specialized leaves (such as those of Nepenthes)

Arrangement on the stem

Different terms are usually used to describe leaf placement (phyllotaxis):
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The leaves on this plant are arranged in pairs opposite one another, with successive pairs at right angles to each other ("decussate") along the red stem. Note developing buds in the axils of these leaves.

• Alternate — leaf attachments are singular at nodes, and leaves alternate direction, to a greater or lesser degree, along the stem.
• Opposite — Two structures, one on each opposite side of the stem, typically leaves, branches, or flower parts. Leaf attachments are paired at each node; decussate if, as typical, each successive pair is rotated 90° progressing along the stem; or distichous if not rotated, but two-ranked (in the same geometric flat-plane).
• Whorled — three or more leaves attach at each point or node on the stem. As with opposite leaves, successive whorls may or may not be decussate, rotated by half the angle between the leaves in the whorl (i.e., successive whorls of three rotated 60°, whorls of four rotated 45°, etc.). Opposite leaves may appear whorled near the tip of the stem.
• Rosulate — leaves form a rosette

As a stem grows, leaves tend to appear arranged around the stem in a way that optimizes yield of light. In essence, leaves form a helix pattern centred around the stem, either clockwise or counterclockwise, with (depending upon the species) the same angle of divergence. There is a regularity in these angles and they follow the numbers in a Fibonacci sequence: 1/2, 2/3, 3/5, 5/8, 8/13, 13/21, 21/34, 34/55, 55/89. This series tends to a limit close to 360° x 34/89 = 137.52 or 137° 30', an angle known mathematically as the golden angle. In the series, the numerator indicates the number of complete turns or "gyres" until a leaf arrives at the initial position. The denominator indicates the number of leaves in the arrangement. This can be demonstrated by the following:

• alternate leaves have an angle of 180° (or 1/2)
• 120° (or 1/3) : three leaves in one circle
• 144° (or 2/5) : five leaves in two gyres
• 135° (or 3/8) : eight leaves in three gyres.

Divisions of the blade


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A leaf with laminar structure and pinnate venation


Two basic forms of leaves can be described considering the way the blade (lamina) is divided. A simple leaf has an undivided blade. However, the leaf shape may be formed of lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade separated along a main or secondary vein. Because each leaflet can appear to be a simple leaf, it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae. The middle vein of a compound leaf or a frond, when it is present, is called a rachis.

• Palmately compound leaves have the leaflets radiating from the end of the petiole, like fingers off the palm of a hand, e.g. Cannabis (hemp) and Aesculus (buckeyes).
• Pinnately compound leaves have the leaflets arranged along the main or mid-vein.
  • odd pinnate: with a terminal leaflet, e.g. Fraxinus (ash).
  • even pinnate: lacking a terminal leaflet, e.g. Swietenia (mahogany).
• Bipinnately compound leaves are twice divided: the leaflets are arranged along a secondary vein that is one of several branching off the rachis. Each leaflet is called a "pinnule". The pinnules on one secondary vein are called "pinna"; e.g. Albizia (silk tree).
• trifoliate (or trifoliolate): a pinnate leaf with just three leaflets, e.g. Trifolium (clover), Laburnum (laburnum).
• pinnatifid: pinnately dissected to the central vein, but with the leaflets not entirely separate, e.g. Polypodium, some Sorbus (whitebeams). In pinnately veined leaves the central vein in known as the midrib.

Characteristics of the petiole

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The overgrown petioles of Rhubarb (Rheum rhabarbarum) are edible.


Petiolated leaves have a petiole (leaf stem). Sessile leaves do not: the blade attaches directly to the stem. In clasping or decurrent leaves, the blade partially or wholly surrounds the stem, often giving the impression that the shoot grows through the leaf. When this is actually the case, the leaves are called "perfoliate", such as in Claytonia perfoliata. In peltate leaves, the petiole attaches to the blade inside from the blade margin.
In some Acacia species, such as the Koa Tree (Acacia koa), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes. There may or may not be normal pinnate leaves at the tip of the phyllode.
A stipule, present on the leaves of many dicotyledons, is an appendage on each side at the base of the petiole resembling a small leaf. Stipules may be lasting and not be shed (a stipulate leaf, such as in roses and beans), or be shed as the leaf expands, leaving a stipule scar on the twig (an exstipulate leaf).

• The situation, arrangement, and structure of the stipules is called the "stipulation".
  • free
  • adnate : fused to the petiole base
  • ochreate : provided with ochrea, or sheath-formed stipules, e.g. rhubarb,
  • encircling the petiole base
  • interpetiolar : between the petioles of two opposite leaves.
  • intrapetiolar : between the petiole and the subtending stem

Venation


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Branching veins on underside of taro leaf


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The venation within the bract of a Lime tree.


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The lower epidermis of Tilia x europea


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Palmate-veined leaf


There are two subtypes of venation, namely, craspedodromous, where the major veins stretch up to the margin of the leaf, and camptodromous, when major veins extend close to the margin, but bend before they intersect with the margin.

• Feather-veined, reticulate (also called pinnate-netted, penniribbed, penninerved, or penniveined) — the veins arise pinnately from a single mid-vein and subdivide into veinlets. These, in turn, form a complicated network. This type of venation is typical for (but by no means limited to) dicotyledons.
• Three main veins branch at the base of the lamina and run essentially parallel subsequently, as in Ceanothus. A similar pattern (with 3-7 veins) is especially conspicuous in Melastomataceae.
• Palmate-netted, palmate-veined, fan-veined; several main veins diverge from near the leaf base where the petiole attaches, and radiate toward the edge of the leaf; e.g. most Acer (maples).
• Parallel-veined, parallel-ribbed, parallel-nerved, penniparallel — veins run parallel for the length of the leaf, from the base to the apex. Commissural veins (small veins) connect the major parallel veins. Typical for most monocotyledons, such as grasses.
• Dichotomous — There are no dominant bundles, with the veins forking regularly by pairs; found in Ginkgo and some pteridophytes.

Note that although it is the more complex pattern, branching veins appear to be plesiomorphic and in some form were present in ancient seed plants as long as 250 million years ago. A pseudo-reticulate venation that is actually a highly modified penniparallel one is an autapomorphy of some Melanthiaceae which are monocots, e.g. Paris quadrifolia (True-lover's Knot).
Morphology changes within a single plant

• Homoblasty - Characteristic in which a plant has small changes in leaf size, shape, and growth habit between juvenile and adult stages.
• Heteroblasty - Characteristic in which a plant has marked changes in leaf size, shape, and growth habit between juvenile and adult stages.

Terminology

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Chart illustrating some leaf morphology terms


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A portion of a celery leaf


Shape

Main article: Leaf shape
Edge (margin)

• ciliate: fringed with hairs
• crenate: wavy-toothed; dentate with rounded teeth, such as Fagus (beech)
• crenulate finely or shallowly crenate
• dentate: toothed, such as Castanea (chestnut)
  • coarse-toothed: with large teeth
  • glandular toothed: with teeth that bear glands.
• denticulate: finely toothed
• doubly toothed: each tooth bearing smaller teeth, such as Ulmus (elm)
• entire: even; with a smooth margin; without toothing
• lobate: indented, with the indentations not reaching to the center, such as many Quercus (oaks)
  • palmately lobed: indented with the indentations reaching to the center, such as Humulus (hop).
• serrate: saw-toothed with asymmetrical teeth pointing forward, such as Urtica (nettle)
• serrulate: finely serrate
• sinuate: with deep, wave-like indentations; coarsely crenate, such as many Rumex (docks)
• spiny or pungent: with stiff, sharp points, such as some Ilex (hollies) and Cirsium (thistles).

Tip


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Leaves showing various morphologies. Clockwise from upper left: tripartite lobation, elliptic with serrulate margin, peltate with palmate venation, acuminate odd-pinnate (center), pinnatisect, lobed, elliptic with entire margin

• acuminate: long-pointed, prolonged into a narrow, tapering point in a concave manner.
• acute: ending in a sharp, but not prolonged point
• cuspidate: with a sharp, elongated, rigid tip; tipped with a cusp.
• emarginate: indented, with a shallow notch at the tip.
• mucronate: abruptly tipped with a small short point, as a continuation of the midrib; tipped with a mucro.
• mucronulate: mucronate, but with a smaller spine.
• obcordate: inversely heart-shaped, deeply notched at the top.
• obtuse: rounded or blunt
• truncate: ending abruptly with a flat end, that looks cut off.

Base

• acuminate: coming to a sharp, narrow, prolonged point.
• acute: coming to a sharp, but not prolonged point.
• auriculate: ear-shaped.
• cordate: heart-shaped with the notch towards the stalk.
• cuneate: wedge-shaped.
• hastate: shaped like an halberd and with the basal lobes pointing outward.
• oblique: slanting.
• reniform: kidney-shaped but rounder and broader than long.
• rounded: curving shape.
• sagittate: shaped like an arrowhead and with the acute basal lobes pointing downward.
• truncate: ending abruptly with a flat end, that looks cut off.

Surface


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Scale-shaped leaves of a Norfolk Island Pine, Araucaria heterophylla.

• farinose: bearing farina; mealy, covered with a waxy, whitish powder.
• glabrous: smooth, not hairy.
• glaucous: with a whitish bloom; covered with a very fine, bluish-white powder.
• glutinous: sticky, viscid.
• papillate, or papillose: bearing papillae (minute, nipple-shaped protuberances).
• pubescent: covered with erect hairs (especially soft and short ones).
• punctate: marked with dots; dotted with depressions or with translucent glands or colored dots.
• rugose: deeply wrinkled; with veins clearly visible.
• scurfy: covered with tiny, broad scalelike particles.
• tuberculate: covered with tubercles; covered with warty prominences.
• verrucose: warted, with warty outgrowths.
• viscid, or viscous: covered with thick, sticky secretions.

The leaf surface is also host to a large variety of microorganisms; in this context it is referred to as the phyllosphere.
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The parallel veins within an iris leaf.


Hairiness


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Common Mullein (Verbascum thapsus) leaves are covered in dense, stellate trichomes.


http://upload.wikimedia.org/wikipedi...chomes_SEM.jpg http://bits.wikimedia.org/skins-1.17...gnify-clip.png
Scanning electron microscope image of trichomes on the lower surface of a Coleus blumei (coleus) leaf.


"Hairs" on plants are properly called trichomes. Leaves can show several degrees of hairiness. The meaning of several of the following terms can overlap.

الليمون يقلل الوزن و يعالج إلتهابات البول
 

الليمون يقلل الوزن و يعالج إلتهابات البول



http://youm7.com/images/NewsPics/lar...1016141914.jpg لليمون فوائد عديدة

تناولت صحيفة الديلى ميل، أهمية تناول ثمرة الليمون بالنسبة للإنسان، وذلك من خلال إصدار نسخة جديدة من كتاب الجائزة الكبرى، والذى تطرق بشكل كبير إلى فوائد مركبات الليمونين، والتى تحتويها ثمرة الليمون خاصة، وأكد أن لها خصائص مضادة للفيروسات، وذكر فائدة زيت الليمون الذى يساعد فى استبعاد الهواء الملوث بالفيروسات من الحلق.

كما أشار الكتاب إلى أن زيت الليمون يحتوى على البكتين وبعض الألياف الطبيعية، والتى تساعد على الشعور بالشبع، مما يقلل من نسبة الدهون التى يمتصها الجسم، كما يساعد فيتامين "ج"، والموجود بنسبة عالية فى الليمون على إنتاج "كارنتينتى"، وهو نوع من الأحماض الأمينية يساعد على حرق الدهون الزائدة عن حاجة الجسم.

كما أشارت إحدى الدراسات، والتى قام بها مجموعة من الباحثين بولاية أريزونا الأمريكية، إلى أن فيتامين "ج" الموجود فى الليمون يساعد فى حرق ما يقرب من 30% من الدهون الزائدة عن حاجة الجسم، كما أكدت الدراسة على أهمية الليمون فى علاج حصوات المرارة، والتى تتكون بفعل زيادة الكولسترول، والتى قد يتسبب فيها نقص حمض المعدة إلا أن الأطعمة الحمضية التى تتواجد فى عصير الليمون قد تثبط من تقلصات المرارة.

كما أشار الباحثون إلى أن الليمون يساعد أيضا فى تقليل الإصابة بعدوى التهابات البول والحلق، حيث يساعد الليمون فى تعديل الأس الهيدروجينى داخل جسم الإنسان، كما يساعد فى تحسين عملية البول، وبالتالى يسهم فى عودة البول إلى حالته الطبيعية، هذا بالإضافة إلى أن البوتاسيوم الموجود فى الليمون يساعد فى تنظيم السوائل بالجسم، وبالتالى يوسع الأوعية الدموية ويجعل ضغط الإنسان ضغطاً مثالياً وفى معدله الطبيعى، نظرا لاحتوائه على مركبات الفلافونويد.

كما أشار الكتاب أيضا إلى أن الليمون يساعد فى علاج كل من السعال وعسر الهضم وأمراض الصدفية، وكذلك يعالج الإمساك وألم العضلات

مصرى خريج علوم المنصوره يدخل ضمن أعظم علماء العالم باكتشافه علاجا للسرطان
 

مصرى خريج علوم المنصوره يدخل ضمن أعظم علماء العالم باكتشافه علاجا للسرطان
بعد 20 عاما من الأبحاث والتجارب تمكن العالم المصري ممدوح غنيم -أستاذ علوم المناعة بجامعة «تشارلز درو» للطب والعلوم- من التوصل إلى علاج طبيعى لمرض السرطان باستخدام الخميرة غير المسببة للأمراض، وأجرى العالم المصري تجاربه فى البداية فى أنابيب ...اختبار، تم خلالها تعريض خلايا سرطانات الثدى واللسان والقولون والجلد للخميرة.

وصرحت الدكتورة مها محمود، مدير المكتب الثقافي والتعليمي بالسفارة المصرية بواشنطن بأن السفارة ستكرم العالم المصري تقديرا لأبحاثه العلمية واكتشافاته التي أثرت العلوم الطبية، مشيرة الي انها اتصلت بالدكتور غنيم لتهنئته على بحثه الذي اكتشف خلاله علاجا للسرطان من الخميرة والذي لاقى أصداء واسعة في عالم الطب في مختلف أنحاء العالم.

وتوصل غنيم إلى هذا الكشف من خلال تبنى نظريته الخاصة بأن الخلايا السرطانية يمكن أن تدمر نفسها عند تعريضها لكميات صغيرة من الخميرة، ولاحظ فى تجاربه أنه عند تعريض الخلايا السرطانية لكميات من الخميرة فإنها تلتهمها من خلال عملية تعرف علميا بـ«الفاجوسايتوسيز» أى الاستيعاب، ثم تموت.

ونقلت وكالة أنباء الشرق الأوسط عن غنيم قوله إنه لا يساوره أى شك فى أنه أصبح قاب قوسين أو أدنى من التوصل إلى سبب ضعف الخلايا السرطانية إلى حد هلاكها بعد أن تلتهم الخميرة المنزلية.. موضحاً أن الخلايا تنجذب نحو الخميرة فى عملية أطلق عليها «الحب القاتل».

وأوضح غنيم أنه حقن الخميرة داخل أورام سرطانية فى الفئران، فلاحظ أن حجم الأورام تقلص، كما أظهرت التجارب الحديثة أنها أبادت قدراً كبيراً من هذه الخلايا فى الرئة، كما لاحظ أن الخلايا تموت حينما تأكل الخميرة. لافتاً إلى أن الخطوة المقبلة ستكون إجراء تجارب سريرية على البشر لتقرير سلامة وفعالية الجرعات وأسلوب العلاج.

الجدير بالذكر أن الدكتور غنيم حصل على بكالوريوس العلوم جامعة المنصورة عام 1973م، ثم سافر لليابان سنة 1980 لتكملة الدراسة هناك ثم عاد يدرس في جامعة المنصورة بعد حصوله على درجة الدكتوراه من جامعة اليابان ودرس سنتين في جامعة المنصورة.

سافر إلى الولايات المتحدة حتى أصبح رئيسا للبحث العلمي بجامعة DRAW بكاليفورنيا وله عدة أبحاث نشرت على مستوى العالم.

والعالم الدكتور قد اكتشف علاجا لجهاز المناعة الذي يدمره مرضى الإيدز والسرطان أيضا، وقد اكتشفه من قش الأرز وعيش الغراب، ولكن عندما عرض هذا الاكتشاف في مصر لم يتمكن من تطبيقه لقلة الإمكانيات ولكنه لم ييأس وأخذ على عاتقه أن يحمل هذا الاكتشاف إلى أي مكان حتى يظهره للعالم باسره والذي يعاني من ضعف جهاز المناعة، ولحبه لمصر ووطنه كانيجب عليه أن يقوم بأي شيء لمساعدة الفقراء والمساكين والمرضى والمحتاجين، فقام بالسفر إلى اليابان حتى توصل إلى العلاجالمناسب ويسمى هذاالعلاج mgn.3 ومعناها "(mg) نسبة إلى اسمه ممدوح غنيم، و natural طبيعي، و.3 أي عدد الجزئيات أو المواد التي أخرج منها الدواء.

وأصبح الآن ممدوح غنيم أعظم وأشهر دكتور في العالم بهذا الاكتشاف العظيم، وهو يكافح حتى يظهر في مصر وبأرخص الاسعار الممكنة، ولهذا فإنه رجلا يستحق الإشادة والتقدير.

العلماء يكتشفون مئات المخلوقات الجديدة
 

مفاتيح من ذهب لفتح ابواب النجاح
 

مفاتيح من ذهب لفتح ابواب النجاح

العطاء يساوي الأخذ: النجاح عمل وجد، وتضحية وصبر، ومن منح طموحه صبراً وعملاً وجداً حصد نجاحاً وثماراً.. فاعمل واجتهد وابذل الجهد لتحقق النجاح والطموح والهدف.. فمن جدّ وجد ومن زرع حصد.

غير رأيك في نفسك: الإنسان يملك طاقات كبيرة وقوى خفية يحتاج أن يزيل عنها غبار التقصير والكسل.. فأنت أقدر مما تتصور، وأقوى مما تتخيل، وأذكى بكثير مما تعتقد.. اشطب كل الكلمات السلبية عن نفسك من مثل: لا أستطيع – لست ذكياً. وردّد باستمرار: أنا أستحق الأفضل – أنا مبدع – أنا ممتاز
– أنا قادر.

النجاح هو ما تصنعه. فكر( بالنجاح – أحب النجاح.. )
النجاح شعور والناجح يبدأ رحلته بحب النجاح والتفكير بالنجاح.. فكر وأحب وابدأ رحلتك نحو هدفك.
تذكر: يبدأ النجاح من الحالة النفسية للفرد، فعليك أن تؤمن بأنك ستنجح – بإذن الله – من أجل أن يكتب لك فعلاً النجاح.
الناجحون لا ينجحون وهم جالسون لاهون ينتظرون النجاح، ولا يعتقدون أنه فرصة حظ، وإنما يصنعونه بالعمل والجد، والتفكير والحب، واستغلال الفرص والاعتماد على ما ينجزونه بأيديهم.

الفشل مجرد حدث.. وتجارب: لا تخش الفشل بل استغله ليكون معبراً لك نحو النجاح لم ينجح أحد دون أن يتعلم من مدرسة النجاح

http://faculty.ksu.edu.sa/21789/Pict...%D8%A9_jpg.jpg
فلنتمسك بهذه المفاتيح ولنضعها في ايدينا دائما ً .

دور التواصل بين المعلم والتلميذ

مراجع مكتبة الأسكندرية .. أدخل وشاهد
 

بالتوفيق والسداد
 

العلماء ورثة الأنبياء



جلست مها تكتب درس التربية الدينية تحت عنوان (العلماء ورثة الأنبياء)
وأخذت تكرر ما تحفظه من الاّيات القراّنية والأحاديث النبوية الشريفة التي توضح فضل العلم ومنزلة العلماء
ووقفت عند هذا الحديث الشريف وهو قول رسول الله صلى الله عليه وسلم: ( إن الله وملائكته وأهل السموات والأرض, حتى النملة في جحرها وحتى الحوت في جوف البحر ليصلون على معلم الناس الخير) رواه الترمذي
الأم: هيا يا مها نتعاون في إعداد مائدة الطعام
مها( وهي تتوجه نحو المطبخ):نعم يا أمي حالا
لمحت مها نملة تمشي في المطبخ فوقفت تنظر لها بدهشة واستغراب وكأنها أول مرة ترى نملة ومشت خلفها حريصة أن تتعرف عليها وتعرف ماذا تفعل؟ وهل حقاً هذه النملة تعرفها وتستغفر لها؟!
قالت في نفسها: إن النمل له لغة وسيدنا سليمان عليه وعلى نبينا الصلاة والسلام علمه الله لغة النمل وكان يحدثهم فلو كانت هذه اللغة تدرس وتعلمتها لخاطبت هذه النملة الصغيرة
النملة :نعم يا مها أنا أفهمكِ هل ترغبين أن تتحاوري معي؟!
مها: سبحان الله، هل حقا تفهمينني أيتها النملة الطيبة؟!
النملة: نعم يا مها إنني أراقبك منذ فترة وأسعد بكِ حينما أراكِ تذاكرين وتحرصين على حفظ القرآن ومدارسة الرياضيات وتعلم اللغات
مها: وهل يسعدك أن أتعلم العلوم الشرعية وأتفوق فيها أم كل العلوم؟
النملة: بالطبع العلوم الشرعية هي أشرف العلوم ولكن البعض يعتقد أن الفضل والأجر للعلم الشرعي فقط ولكن الحقيقة أن أي علم ينفع الناس له نفس الثواب من الله طالما يعود على صاحبه ومن حوله بالخير لأن مهمة الإنسان بعد عبادة الله هي عمارة الأرض ونشر الخير فيها
مها: أنا أسعى للتفوق وأحلم بالمستقبل لأكون ناجحة ولتفخر بي أمي ولأنفع أمتي
النملة:عزيزتي مها المهم النية في الأول و الاّخر, طلب العلم وتعليمه يكون لله تعالى ولخدمة دين الله ولنشر الخير بين الناس ثم بعد ذلك لتسعدي أمك وتنفعي وطنك
مها: وهل تصلون علينا حين نعلم الناس الخير أيتها النملة الودودة؟!
النملة: نعم يا حبيبتي، ليس نحن فقط وإنما الحيتان في البحر كذلك
يكفيه فخراً ومنزلة وشأن عظيم أن الله عز وجل والملائكة التي لا يعرف عددها غير الله يصلون على معلمي الناس الخير!
الأم : مها ماذا تفعلين ؟أين كنت؟
مها :يا آسفة جدا لقد سرحت وتخيلت أنني أتكلم مع النملة
الأم: تتكلمين مع النملة؟! ما أوسع خيالك يا مها!
مها: لقد تعلمت منها الكثير يا أمي وعاهدتها أن أتفوق في دراستي لأنفع نفسي وأمتي
الأم: وفقكِ الله يا حبيبتي وكتب لكِ النجاح دائما

كيف تذاكر
 

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