Volvox is a polyphyletic genus of chlorophyte green algae in the family Volvocaceae. It forms spherical colonies of up to 50,000 cells, they live in a variety of freshwater habitats, were first reported by Antonie van Leeuwenhoek in 1700. Volvox diverged from unicellular ancestors 200 million years ago. Volvox is a polyphyletic genus in the volvocine green algae clade; each mature Volvox colony is composed of up to thousands of cells from two differentiated cell types: numerous flagellate somatic cells and a smaller number of germ cells lacking in soma that are embedded in the surface of a hollow sphere or coenobium containing an extracellular matrix made of glycoproteins. Adult somatic cells comprise a single layer with the flagella facing outward; the cells swim with distinct anterior and posterior poles. The cells have anterior eyespots; the cells of colonies in the more basal Euvolvox clade are interconnected by thin strands of cytoplasm, called protoplasmates. Cell number is dependent on the number of rounds of division.
Volvox can reproduce both sexually and asexually. In the lab, asexual reproduction is most observed; the switch from asexual to sexual reproduction can be triggered by environmental conditions and by the production of a sex-inducing pheromone. Desiccation-resistant diploid zygotes are produced following successful fertilization. An asexual colony includes both somatic cells, which do not reproduce, large, non-motile gonidia in the interior, which produce new colonies through repeated division. In sexual reproduction two types of gametes are produced. Volvox species can be dioecious. Male colonies release numerous sperm packets, while in female colonies single cells enlarge to become oogametes, or eggs. Kirk and Kirk showed that sex-inducing pheromone production can be triggered in somatic cells by a short heat shock given to asexually growing organisms; the induction of sex by heat shock is mediated by oxidative stress that also causes oxidative DNA damage. It has been suggested that switching to the sexual pathway is the key to surviving environmental stresses that include heat and drought.
Consistent with this idea, the induction of sex involves a signal transduction pathway, induced in Volvox by wounding. Colony inversion is a special characteristic during development in the order Volvocaceae that results in new colonies having their flagella facing outwards. During this process the asexual reproductive cells first undergo successive cell divisions to form a concave-to-cup-shaped embryo or plakea composed of a single cell layer. After, the cell layer is inside out compared with the adult configuration—the apical ends of the embryo protoplasts from which flagella are formed, are oriented toward the interior of the plakea; the embryo undergoes inversion, during which the cell layer inverts to form a spheroidal daughter colony with the apical ends and flagella of daughter protoplasts positioned outside. This process enables appropriate locomotion of spheroidal colonies of the Volvocaceae; the mechanism of inversion has been investigated extensively at the cellular and molecular levels using the model species, Volvox carteri.
Volvox is a genus of freshwater algae found in ponds and ditches in shallow puddles. According to Charles Joseph Chamberlain, "The most favorable place to look for it is in the deeper ponds and ditches which receive an abundance of rain water, it has been said that where you find Lemna, you are to find Volvox. Look where you find Sphagnum, Alisma, Equisetum fluviatile, Utricularia and Chara. Dr. Nieuwland reports that Pandorina and Gonium are found as constituents of the green scum on wallows in fields where pigs are kept; the flagellate, Euglena, is associated with these forms." Antonie van Leeuwenhoek first reported observations of Volvox in 1700. After some drawings of Henry Baker, Linnaeus would describe the genus Volvox, with two species: V. globator and V. chaos. Volvox chaos is an amoeba now known as Chaos sp. Ancestors of Volvox transitioned from single cells to form multicellular colonies at least 200 million years ago, during the Triassic period. An estimate using DNA sequences from about 45 different species of volvocine green algae, including Volvox, suggests that the transition from single cells to undifferentiated multicellular colonies took about 35 million years.
Guiry, M. D.. M.. "Volvox". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Volvox description with pictures from a Hosei University website YouTube videos of Volvox: Volvox micro-motility in Lake Oroville, CA Life cycle and inversion Waltzing Volvox Spinning Volvox Volvox, one of the 7 Wonders of the Micro World by Wim van Egmond, from Microscopy-UK Volvox carteri at MetaMicrobe.com, with modes of reproduction, brief facts
The 2018–19 Maltese Premier League was the 104th season of top-flight league football in Malta. The season began on 17 August 2018 and ended in April 2019. Defending champions Valletta won their 25th title, following a penalty shootout win against Hibernians in a championship decider match. Lija Athletic and Naxxar Lions were relegated after they finished thirteenth and fourteenth the previous season, they are replaced by Qormi and Pietà Hotspurs, the 2017–18 Maltese First Division champions and runners-up respectively. Tarxien Rainbows retained Premiership status by defeating Żejtun Corinthians in a play-off decider. Additionally, referee kits are made by Adidas, sponsored by TeamSports and FXDD, Nike has a new match ball; the table lists the positions of teams after each week of matches. In order to preserve chronological evolvements, any postponed matches are not included to the round at which they were scheduled, but added to the full round they were played afterwards. At the end of the season and Hibernians finished off equal on 58 points.
Hibernians had a convincing 5–1 win over Balzan to force a championship decider to be played between the two on 18 May. Valletta qualified for the 2019–20 UEFA Champions League First qualifying round. Hibernians qualified for the 2019–20 UEFA Europa League First qualifying round. A play-off match took place between the twelfth-placed team from the Premier League, St. Andrews, the third-placed team from the First Division, St. Lucia, for a place in the 2019–20 Maltese Premier League. St. Lucia became the first First Division club to win a Premier League play-off, thereby booking a place in next season's Premier League for the first time in their history; as of 5 May 2019 Official website
Thorulf or Torulf was medieval prelate, a Bishop of Orkney. Although a native Scandinavian, he is known only from the account of the German writer Adam of Bremen. Adam reported that he was appointed bishop by Adalbert, Archbishop of Hamburg, the first Orcadian appointee under Hamburg overlordship. Thorulf's period of appointment coincided with the reign of Earl Thorfinn Sigurdsson, alleged builder of the Birsay church and founder of the bishopric of Orkney. Thorulf is known only from one source. According to the late 11th-century Saxon writer Adam of Bremen, he was appointed as bishop of Blascona in Orkney by Adalbert, Archbishop of Hamburg. In the mid-11th century, the Archbishop of Hamburg's jurisdiction extended over Scandinavia. Historians identify Blascona with Birsay, Blascona a Latinisation derived from an older form. Adam leaves no personal details about Thorulf, but supplies some information about the Orkney see, stating that the:... Orkney Islands, although they had been ruled by English and Scottish bishops, our primate on the pope's order consecrated Thorulf bishop for the city of Birsay, he was to have cure of all.
The date was 1050, though could have been at any point between 1043 and 1072, the episcopate of Adalbert. The date 1050 is suggested as this was around the time that Earl Thorfinn Sigurdsson, ruler of Orkney, visited Rome; as Adam mentioned that the Orcadians had sent legates, it is thought that Thorulf was appointed at Orcadian instigation, it has be suggested that the earl himself was among these legates. Historian Barbara Crawford thought that Thorulf was a Scandindavian, a close associate of the earl; the Orkneyinga saga related that Birsay was the permanent residence of Earl Thorfinn, that the earl built a minster there as the seat of the first Orkney bishop. Although this specific claim may not be true, it is taken as evidence that Thorfinn's reign was a significant turning point for the earldom, suggesting according to historian Ronald Cant "a deliberate plan on the part of the earl to perfect the organization of the church in Orkney". Thorfinn and Thorulf's Christ Church has been identified with the Romanesque ruins on the tidal island known as Brough of Birsay, but there is evidence that it was located over in the Mainland next to the Earl's palace
Trapania tora is a species of sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae. This species was described from Indonesia, it has since been reported from Kwajalein in the Marshall Islands. This goniodorid nudibranch is black or dark grey in colour, with a pattern of white patches and thin white lines forming a network on the body. There are rounded tubercles on the back and behind the gills which are white; the gills and rhinophores are translucent with white superficial pigment. The oral tentacles have the body pattern at white tips. Trapania tora feeds on Entoprocta which grow on sponges and other living substrata
Jeannette Scott was a Canadian-born American painter. She became the head of the painting department at Syracuse University. Scott was born in 1864 in Kincardine, Canada. Upon the death of her father, when she was twenty-one, she moved to the United States where she studied at the Philadelphia School of Design for Women, there her professors included Emily Sartain, she studied at the Pennsylvania Academy of the Fine Arts. From 1889 to 1894, Scott studied in Paris at the Académie Colarossi, her teachers in Paris included Joseph Blanc, Gustave-Claude-Etienne Courtois, Alphonse Mucha. Scott exhibited her work at the Palace of Fine Arts at the 1893 World's Columbian Exposition in Chicago, Illinois. Scott exhibited her art the Boston Art Club and the National Academy of Design in New York. Scott was a member of the American Federation of Arts, she worked with the Inter-American Commission of Women. In 1895, Scott became a professor of painting in the College of Fine Arts at Syracuse University. In 1902 she became head of the painting department, when she retired.
Scott died in 1937 in Skaneateles, New York
Lexington Public Schools is a public school district in Lexington, United States. The district consists of six elementary schools, two middle schools, a high school; each elementary and middle school is named after an important figure in Lexington's history. There are nine schools in the Lexington Public School district: Bowman Elementary School Bridge Elementary School Joseph Estabrook Elementary School Fiske Elementary School Harrington Elementary School Maria Hastings Elementary School Jonas Clarke Middle School William Diamond Middle School Lexington High School Lexington's six elementary schools - Bowman, Joseph Estabrook, Fiske and Maria Hastings - serve students in kindergarten through 5th grade. Bowman Elementary is named for the descendants of Nathaniel Bowman, the progenitor of an important family in Lexington's history; the current principal at Bowman is Jen Courduck. The mascot of the school is the Bowman Bear. Bridge Elementary is named for the descendants of Matthew Bridge, to whom the once-farmland around the school site belonged.
A mural on the front side of the school building represents "working together". The current principal at Bridge is Meg Colella. Bridge was a High Performing National Blue Ribbon School in 2010. Estabrook Elementary is named after the first schoolteacher in Lexington, it is notable for being the oldest Lexington Elementary school. The current principal at Estabrook is Rick Rogers; the school garnered nationwide attention from the David Parker controversy, when parents sued the Lexington school system, arguing that their children were being coerced by public school teachers "to affirm the correctness and the normalcy of homosexuality" and same-sex marriage. The bulk of the legality of the controversy revolved around whether parents have a right to receive parental notification and opt their elementary school children out of such content. Federal courts ruled against the Parkers. Fiske Elementary is named for the Fiske family, which circa 1678 was the first family to settle on East Street; the current principal at Fiske is Thomas Martellone.
The current facility was constructed between 2005 and 2007. Harrington Elementary is named for the Harrington family, which produced many notable town citizens, such as Jonathan Harrington, killed in the Battle of Lexington, another of the same name, the battle's last survivor; the current principal at Harrington is Jackie Daley. Maria Hastings Elementary is named after Maria Hastings Cary, a local philanthropist and the founder of the town's main public library, Cary Library; the current principal at Hastings is Louise Lipsitz. Lexington's two public middle schools - William Diamond MS and Jonas Clarke MS referred to as "Diamond" and "Clarke," - serve students between 6th and 8th grade. Students at Diamond are fed in through Estabrook and Hastings, students at Clarke are fed in through Bowman and Harrington. Like many middle schools, both Diamond and Clarke operate in an academic team system, in which each grade is broken down into smaller groups of common teachers and students; each of the grades in both schools are divided with one exception.
Diamond and Clarke have built a cross-town rivalry bridging athletics. Both Diamond and Clarke have been among the top schools in MCAS testing. Academically, both schools offer a comparable curriculum comprising several core subjects in addition to a wide range of electives. Students are required to take courses in math, science and social studies, each of which follows its own track. In math, students are required to take courses ranging up to algebra, with placement and level being determined individually. In science, students are required to take courses in earth science, life science, chemistry and physics. In social studies, students are required to take courses focusing on ancient civilizations, world geography, U. S. history in 6th, 7th and 8th grades respectively. In foreign languages, students have the option to take a sequence of courses in French, Spanish, or Mandarin Chinese; the Mandarin Language program is ranked one of the best Mandarin Language programs in the country, the school and Mandarin teachers have received many awards, such as the Confucius Institute Award and various cash and technological prizes from the Chinese Government.
Top students in Spanish have the opportunity to visit Costa Rica, or in past and recent years, Spain, as part of a language and culture immersion trip abroad. Top students in French have the opportunity to visit Quebec City, top students in Mandarin have the opportunity to visit Beijing and Shanghai, China. Students in both schools have the additional opportunity to participate in their respective school's orchestra, band, or chorus. Both schools field varsity teams in many sports, including cross-country running, basketball, field hockey and softball. Led by coaches Sarah Doonan at Diamond and Joshua Frost and Jeffrey Woodcock at Clarke, Lexington's middle school math teams are renowned for their successes and mutual rivalry in competitions such as MathCounts, the NEML, the American Mathematics Competitions, in the Intermediate Math League of Eastern Massachusetts. Clarke's current run of seven consecutive IMLEM championships was preceded by nine consecutive championships by Diamond. Two Lexington natives have won the Mathcounts national championship: Jonathan L. Weinstein in 1991 and Alec Sun in 2013.
Both schools have a plethora of other teams. The school is named after William Diamond, the 16-year-old drummer for the Lexington Minutemen during the Battle of Lexington and Concord; the current principal at Diamond is Jennif