A mother goddess is a goddess that is a personification of motherhood, or of fertility. Sometimes, they are called mother earth or earth mother. This concept is usually coupled with a sky father, or father sky. Very often, the mother goddess is also the mother of other deities.
Dynamical system
A Dynamical system is a mathematical model of a process, that is dependent on time. The process is homogeneous, it only depends on the initial state. The current terminology was established by Henri Poincaré and George David Birkhoff.
Dynamical systems are very common. Examples are the movement of a pendulum in physics, or the predator-prey equations in biology.
Predator-prey equations
The predator-prey equations is a system of two linked equations that models two species that depend on each other: One is the prey, which provides food for the other, the predator. Both prey and predator populations grow if conditions are right. Alfred J. Lotka found these equations in 1925. Vito Volterra found them, independently, in 1926. For this reason, the equations are also called Lotka-Volterra equations.
The equations themselves are non-linear differential equations.
There are a number of pre-conditions
In this case the solution of the differential equations is deterministic and continuous. This means that the generations of both the predator and prey are overlapping all the time.
The solutions to the equations lead to the Lotka-Volterra rules:
In one of his books, Volterra provided statistics on the number of certain cartilagenous fish caught at some Italian ports in the Mediterranean. Volterra used the term "sélaciens", which refers to sharks. These often prey on other fish. In the table, Volterra provided numbers for 1905, and 1910 to 1923:
He observed that between 1915 and 1920, more of these fish were caught. He expained this as follows: During the First World War, less fishing was done. For this reason, there were more prey animals, so the number of predators increased. After the war, fishing increased again, reducing the number of prey animals. This also led to a decrease in the number of predators, which can be seen in the table above.
The use of the first Lotka-Volerra rule in economics is known as pork cycle.
The predator-prey equations have also been the foundation of other work. Volterra himselft extended it to be able to model intraspecific competition. Intraspecific competition occurs when two aninimals of the same species compete for limited resources. Intraspecific competition is an important factor to regulate population density. It is also important to be able to adapt to a changing environment (and for evoution). Volterra did this by adding new terns to the equation.
Most of Volerra's work is about extending the model to be able to handle more than two classes of animals interacting.
Bat Trang Pottery Village
Bat Trang is a historic village in Vietnam, famous for making traditional pottery and ceramics. Bat Trang Village is a popular tourist destination in North Vietnam. The famous village produces and trades many kinds of ceramics inside and outside the country.
Bat Trang pottery village was established about 1000 years ago in the Red River Delta region of Vietnam. Located in an area rich in white clay, the people of the village had the advantage of producing pottery. Five famous pottery families of Bo Bat village (now Ninh Bình Province) came and brought pottery artisans to Bat Trang village. The five families and the Nguyen family of Bat Trang opened the first pottery production kilns in the village. About the 12th century, Hua Vinh Kieu learned some new techniques of pottery production from Guangdong Province in China and taught Bat Trang pottery makers how to make a white glaze.
Bat Trang village has produced pottery since the 11th century. During the 11th and 12th centuries, the Ly Emperors chose the Bat Trang pottery as a tribute for the Chinese Emperor. The village has about 80 percent of the 1200 kilns that had fired ceramics since the village was established. Throughout the years, the village's products have become more diversified. Bat Trang potteries are well-known and have gained popularity in many countries.
Bat Trang products are classified into three different kinds depending on their usage.
•           Household items: plates, bowls, teacups, kettles, wine bottles, flowerpots, vases, jars, cups, pots, etc.
•           Religious items: lamp stands, candle holders, incense burners, altar boxes, swords, etc.
•           Decorative objects: altars, statues, and architectural fixtures.
Since the village was established, most residents there have been involved in the pottery business. The economy of the village now depends on tourism and sales of the pottery. Besides making income, the people also want to teach the craft and to keep the old skills alive.
Bat Trang ceramic village has become popular with tourists. Visitors can study the history, culture, and traditional worth of each of the handicraft products.
Bat Trang village festival is organized from the 14th to 16th day of the second lunar month each year. The festival brings various special activities to honor the first pottery making. The people of the village have some traditional games such as  "xiangqi" (or Chinese chess), chessboard, tug of war, choir. Many special ceramic products of the village's best craftsmen are displayed at the time.
The largest Bat Trang pottery market displays and sells many ceramic products of the village. Visitors can buy and learn to make pottery products. Located at the entrance to Bat Trang village, the market covers an area of about 20,000 feet (6000 meters).
Van Van is a private museum of the traditional pottery of Bat Trang village.  Mr. Tran Ngoc Lam, a member of the UNESCO Center for Research and Conservation of Vietnam Antiques, built the museum in 2002. The museum includes 3 old houses from the 19th century. It displays more than 400 pottery products that were made from the 15th century to the 19th century by the people of the Bat Trang village.
Bat Trang is a small village in the North of Vietnam. The village belongs to the Gia Lâm district of  Ha Noi capital. Bat Trang is located on the other side of Chuong Duong bridge, about 8 miles (13 kilometers) southeast from Ha Noi center.
Ethiopian-Eritrean Evangelicalism
P'ent'ay (from Ge'ez Script: ጴንጤ) is an originally Amharic-Tigrinya language term for Pentecostal Protestant Christians within Ethiopia and Eritrea, and the Ethiopian and Eritrean diaspora. Today, the term refers to all Evangelical Christian denominations and organisations in Ethiopian and Eritrean societies as Ethiopian-Eritrean Evangelicalism or the Ethiopian-Eritrean Evangelical Church. Sometimes the denominations and organisations are also known as Wenigēlawī (from Ge'ez Script: ወንጌላዊ).
Ethiopian and Eritrean Evangelical Christians are the result of American and European Protestant missionary work among youth who left the Orthodox Tewahedo churches because of theological differences, and later fanned by persecution against them. P'ent'ay Christians schismed from the Orthodox Tewahedo churches, other branches of Christianity, or converted from other religions with the aid of Protestant missionaries to reform Ethiopian Christianity from what they perceived doctrinal-theological diversions. Since the creation of P'ent'ay churches and organisations, prominent movements among them have been Pentecostalism, the Baptist tradition, Lutheranism, Methodism, Presbyterianism, and the Mennonites.