Polaris

Polaris, designated Ursae Minoris, commonly the North Star or Pole Star, is the brighest star in the constellation of Ursa Minor. It is very close to the north celestial pole, making it the current northern pole star. The revised Hipparcos parallax gives a distance to Polaris of about 433 light-years (133 parsecs), while calculations by other methods derive distances around 30% closer. 

Polaris is a triple star system, composed of the primary star, Polaris Aa (a yellow supergiant), in orbit with a smaller companion (Polaris Ab); the pair in orbit with Polaris B (discovered in August 1779 by William Herschel). There were once thought to be two more distant component, Polaris C and Polaris D, but these have been shown not to be physically associated with the Polaris system. 

Polaris Aa is a 5.4 solar mass F7 yellow supergiant of spectral type IB. It is the first classical Cepheid to have a mass determined from its orbit. The two smaller companions are Polaris B, a 1.39 F3 main-sequence star orbiting at a distance of 2400 astronomical units (AU), and Polaris Ab (or P), a very close F6 main-sequence star with an 18.8 AU radius orbit and 1.26.

Polaris B can be seen even with a modest telescope. William Herschel discovered the star in August 1779 using a reflecting telescope of his own, one of the best telescopes of the time. By examining the spectrum of Polaris A, it was also discovered in 1929 that it was a very close binary, with the secondary being a dwarf, which had been theorized in earlier observations. In January 2006, NASA, released images, from the Hubble telescope, that showed the three members of the Polaris ternary system.

Ab, the nearby dwarf star, is in an orbit of 18.5 AU (2.8 billion km) from Polaris Aa, about the distance between the Sun and Uranus, which explains why its light is swamped by its close and much brigher companion. Polaris Aa, the supergiant primary component, is a low-amplitude Population I classical Cepheid variable, although it was once thought to be a type II Cepheid due to its high galactic latitude. Cepheids constitute an important standard candle for determining distance, so Polaris, as the closest such star, is heavily studied.

Invasive species

An invasive species is a species that is not native to a specific location (an introduced species), and that has a tendency to spread to a degree believed to cause damage to the environment, human economy or human health. The term as most often used applies to introduced species that adversely affect the habitats and bioregions they invade economically, environmentally, or ecologically. 

Such species may be either plants or animals and may disrupt by dominating a region, wilderness areas, particular habitats, or wildland-urban interface land from loss or natural controls (such as predators or herbivores).  This includes plan species labeled as exotic pest plants and invasive exotics growing in native plant communities. The European Union defines "Invasive Alien Species" as those that are, firstly, outside their natural distribution area, and secondly, threaten biological diversity.

The term is also used by land managers, botanists, researchers, horticulturalists, conservationists, and the public for noxious weeds. The term "invasive" is often poorly defined or very subjective and some broaden the term to include indigenous or "native" species, that have colonized natural areas, for example, deer considered by some to be overpopulating their native zones and adjacent suburban gardens in the Northeastern and Pacific Coast regions of the United States.

The definition of "native" is also sometimes controversial. For example, the ancestors of Equus ferus (modern horses) evolved in North America and radiated to Eurasia before becoming locally extinct. Upon returning to North America in 1493 during their hominid-assited migration, it is debatable as to whether they were native or exotic to the continent of their evolutionary ancestors.

Notable examples of invasive plant species include the kudzu vine, Andean pampas grass, and yellow star-thistle. Animal examples include the New Zealand mud snail, feral pigs, European rabbits, grey squirrels, domestic cats, carp and ferrets. Invasion of long-established ecosystems by organisms from distant bio-regions is a natural phenomenon, but has been accelerated massively by humans, from their earliest migrations though to the age of discovery, and now international trade.

While all species compete to survive, invasive species appear to have specific traits or specific combinations of traits that allow them to outcompete native species. In some cases, the competition is about rates of growth and reproduction. In other cases, species interact with each other more directly. Researchers disagree about the usefulness of traits as invasiveness markers. One study found that of a list of invasive and noinvasive species, 86% of the invasive species could be identified from the traits alone.

Another study found invasive species tended to have only a small subset of the presumed traits and that many similar traits were found in noinvasive species, requiring other explanations. Common invasive species traits include the following: 

- Fast growth
- Rapid reproduction 
- High dispersal ability
- Phenotype plasticity
- Tolerance of a wide range of environmental conditions
- Ability to live off of a wide range of food types
- Association with humans
- Prior successful invasions

Typically, an introduced species must survive at low population densities before it becomes invasive in a new location. At low population densities, it can be difficult for the introduced species to reproduce and maintain itself in a new location, so a species might reach a location multiple times before it becomes established. Repeated patterns of human movement, such as ships sailing to and from ports or cars driving up a down highways offer repeated opportunities for establishment (also known as a high propagule pressure).

An introduced species might become invasive of it can outcompete native species for resources such as nutrients, light, physical space, water, or food. If these species evolved under great competition or predation, then the new environment may host fewer able competitors, allowing the invader to proliferate quickly. Ecosystems which are being used to their fullest capacity by native species can be modeled as zero-sum systems in which any gain for the invader is a loss for the native. However, such unilateral competitive superiority (and extinction of native species with increased populations of the invader) is not the rule. 

Invasive species often coexist with native species for an extended time, and gradually, the superior competitive ability of an invasive species becomes apparent as its population grows larger and denser and it adapts to its new location. An invasive species might be able to use resources that were previously unavailable to native species, such as deep water sources accessed by a long taproot, or an ability to live on previously uninhabited soil types. For example, barbed goatgrass was introduced to California on serpentine soils, which have low water-retention, low nutrient levels, a high magnesium/calcium ratio, and possible heavy metal toxicity. Plant populations on these soils tend to show low density, but goatgrass can form dense stands on these soils and crowd out native species that have adapted poorly to serpentine soils.

Chess and Health

In recent decades there is a boom in the publication of scientific studies and doctoral theses on the contribution of chess in different areas of human life: educational, social and therapeutic. The results of the different studies usually lead to similar conclusions: chess is a cognitive and emotional training that intervenes in the improvement of planning organization, problem solving attention, viso-spatial capacity, memory, emotional intelligence, among others.

Thanks to the advance of science and technology, instruments are being developed that allow us to study both the architecture and the functioning of the human brain, and in our case, it gives us the possibility of knowing the chess brain. I like to higlight the different studies published in the last decade by psychologists and scientific critics Bilalic, M. and Gobet, F. which they conclude how the brain of a chess player works differently from the non-player: 

For example, they checked how the chess players had greater activation of the lower left area of the parietal lobe, the medial para-hippocampal cortex and the fusiform area. The different investigations carried out by the group of Campitelli, G. concluded that playing chess produces a bilateral activation of the cingulum, cerebellum and frontal lobe.

ELO

The Elo rating system is a method for calculating the relative skill levels of players in zero-sum games such as chess. It is named after its creator Arpad Elo, a Hungarian-American physics professor. The Elo system was originally invented as an improved chess rating system over the previously used Harkness system, but is also used as a rating system for multiplayer competition in a number of video games, association football, American football, basketball, Major League Baseball, table tennis, Scrabble, board games such as Diplomacy and other games.

The difference in the ratings between two players serves as a predictor of the outcome of a match. Two players with equal ratings who play against each other are expected to score an equal number of wins. A player whose rating is 100 points greater than their opponent's is expected to score 64%; if the difference is 200 points, then the expected score for the stronger player is 76%. 

A player's Eo rating is represented by a number with increases or decreases depending on the outcome of games between rated players. After every game, the winning player takes points from the losing one. The difference between the ratings of the winner and loser determines the total number of points gained or lost after a game. In a series of games between a high-rated player and a low-rated played, the high-rated player is expected to score more wins. 

If the high-rated player wins, then only a few rating points will be taken from the low-rated player. However, if the lower-rated player scores an upset win, many rating points will be transferred. The lower-rated player will also gain a few points from the higher rated player in the event of a draw. This means that this rating system is self-correcting. Players whose ratings are too low should, in the long run, do better than the rating system predicts and thus gain rating points until the ratings reflect their true playing strengh.

Arpad Elo was a master-level chess player and an active participant in the US Chess Federation (USCF) from its founding in 1939. The USCF used a numerical ratings system, devised by Kenneth Harkness, to allow members to track their individual progress in terms other than tournament wins and losses. The Harkness system was reasonably fair, but in some circumstances gave rise to ratings which many observers considered inaccurate. On behalf of the USCF, Elo devised a new system with a more sound statistical basis.

Elo's system replaced earlier systems of competitive rewards with a system based on statistical estimation. Rating systems for many sports award points in accordance with subjective evaluations of the "greatness" of certain achievements. For example, winning an important golf tournament might be worth and arbitrarily chosen five times as a many points as winning a lesser tournament.

Chess and Education

Chess is on its way to being implemented in schools, after unanimously approving the non-law proporsal that the PSOE (Spain) has presented in the Education and Sports Commission of the Congress. After this first step, Pablo Martín, deputy who has debated the proposal, explains to Verne that the objective is that this "very useful pedagogical tool that has a very small cost" ends up being a school subject.

Martín himself is fond of chess and, in fact, prepared the proposal with the help of Juan Ramón Galiana, his chess teacher in Mallorca, and Leontxo García, a specialized journalist collaborating with El País and author or a report that summarizes the benefits that He has chess for children. This report recalls that the proposal is not born from scratch: there are already more than 300 public and private schools in chess is a compulsory subject, following the recommendation made in 2012 by the European Parliament.

 1. Help develop intelligence: according to the report by Leontxo García, which collects data from studies published in several countries, "chess children develop more intelligence and achieve better academic results (by 17% on average) than non-chess players, especially in mathematics and reading (precisely the two fields where Spanish students fail most, according to the Pisa Report)". 

To give other examples: a report from the Kasparov Chess Foundation collects the results of various studies that show how chess improves creativity, problem solving, memory and concentration. Another test conducted in serveral Italian schools shows that this game contributes to the improvement of academic performance.

2. And not only intelligence: Miguel López, who has been a chess teacher, explains that this game helps children improve "their ability to concentrate and also to mature. They see that the acts have consequences and this helps them not to be excessively impulsive." For example, rules such as touched piece, played piece help to think before acting.

Leontxo García lists in his report the five intelligences that chess develops (of the eight in the Howard Garner classification): logical-mathematical, linguistic, spatial, intrapersonal and interpersonal.

3. It is good for the little ones: López points out that you can teach even after three years; "the smaller, the better, because it will influence your ability to reflect and your patience. Although you can't demand that they play a three-hour game."

Leontxo García considers it interesting how it helps preschool children (3-5 years old) "because it shows that - contrary to what the experts maintained until recently - abstract intelligence can be worked before 6 years", which is why Pablo Martín explains that the PSOE (Spain) will propose that "chess enters as a subject in primary education". (Also because "the high school curriculum is more loaded." García mentions the example of the Colombian Adriana Salazar, in whose center in Bogotá "4-year-old children play chess, play the violin and practice taekwondo. It uses the transverse method (teaches geometry and encourages spatial vision, among many other applications), which has also worked well with older children (for example, when explaining universal history in parallel with the history of chess)."

4. It is good for the elderly: "the frequent practice of chess delays and improves brain aging, and could prevent and delay Alzheimer's disease," explains Leontxo García, who describes the game as a "mental gym." 

5. It is a game: the game is the child's way of learning to relate to the world, improves social skills and imagination, and encourages creativity, as well as helping learn social norms and cope with frustration: "in chess you lose, as in any game, and nothing happens," López tells us. 

The fact that it is a game is also an extra motivating factor: "at the outset, it is more fun than a class," notes López, who still remembers that in the lessons he taught (optional), "you could quickly see who He had signed up for interest and who, bound by his parents."

6. But it is not just any game: the game always has positive effects for a child, but chess has other advantages over bridge, for example, which is studied in many universities because of its relationship with mathematics: "there is no luck factor," say López, recalling that the players they do not depend on the distribution of cards or the result of a roll of dice. "And in addition there are many variants. No two chess games are the same." Leontxo García adds that its infrastructure is cheap, that it is universal, that it has more than 15 centuries of history and, above all, that it has "very interesting connections with art, science, computers, pedagogy and psychology". 

Scholar's mate

In chess, Scholar's Mate is the checkmate achieved by the following moves, or similar:

1. e4 e5

2. Bc4 Nc6

3. Qh5 Nf6??

4. Qxf7++

The same mating pattern may be reached by various move orders. For example, White might lay 2. Qh5, or Black might play 2...Bc5. In all variations, the basic idea is the same: the queen and bishop combine in a simple mating attack on f7 (or f2 if Black is performing the mate).

Scholar's mate is sometimes referred to as the "four-move checkmate", although there are other ways to checkmate in four moves. Unlike Fool's Mate, which rarely occurs at any level, games ending in Scholar's Mate are quite common among beginners. It is not difficult to parry, however.

On move 1

After 1.e4, Black can play a semi-open defense instead of 1...e5. Openings such as the French Defense (1...e6) or the Scandinavian Defense (1...d5) render Scholar's Mate unviable, while other openings such as the Sicilian Defense (1...c5) make 2. Bc4 a bad move (1. e4 c5 2. Bc4? e6, intending ...d5, gaining time by attacking the c4-bishop and attaining easy equality).

On move 2

The most common response to the Bishop's Opening (1e4 e5 2. Bc4) is 2...Nf6 (see Bishop's Opening, Berlin Defense), which also renders Scholar's Mate unviable.

On move 3

After 1.e4 e5 2. Bc4 Nc6 3. Qh5, the cleanest way to defend against the mate threat is 3...g6. Should White renew the Qxf7 threat with 4. Qf3, Black can easily defend by 4...Nf6 (see diagram), and develop the f8-bishop later via fianchetto (...Bg7).

Fool's mate

Fool's mate, also known as the Two-Move Checkmate, is the checkmate in the fewest possible number of moves from the start of the game. This can be achieved only by Black, who can deliver checkmate on move 2 with the queen. Fool's Mate received its name because it can only occur if White commits and extraordinary blunder. Even among rank beginners, the mate almost never occurs in practice.

An example of Fool's Mate consists of the moves:

1. f3 e5

2. g4?? Qh4#

Resulting in the position shown. The pattern can have slight variations; Black could play ...e6 or ...e5, and White could play f4 rather than f3. Additionally the order in which White advances their f- and g-pawns could be alternated.

Similar mating patterns can occur early in the game. For example, in 1. e4 g5 2. d4 f6?? 3. Qh5#, the basic Fool's Mate pattern is the same: a player advances their f- and g-pawns, which permits the enemy queen to mate along the unblocked diagonal. One such Fool's Mate is widely reported to have occurred in a possibly apocryphal 1959 game between Masefield and Trinka, which lasted just three moves: 1. e4 g5 2. Nc3 f5?? 3. Qh5#. A similar mate can occur in From's Gambit: 1. f4 e5 2. g3? exf4 3. gxf4?? Qh4#.

Teed vs Delmar

A well-known trap in the Dutch Defense ocurred in the game Frank Melville Teed - Eugene Delmar, 1896:

1. d4 f5 2. Bg5 h6 3. Bf4 g5 4. Bg3 f4. 

It seems that Black has won the bishop, but now comes... 5. e3

Threating Qh5#, a basic Fool's Mate.

Sherlock

Sherlock is a British crime drama television series based on Sir Arthur Conan Doyle's Sherlock Holmes detective stories. Created by Steven Moffat and Mark Gatiss, it stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Doctor John Watson. 13 episodes have been produced, with four three-part series airing from 2010 to 2017, and a special episode that aired on 1 January 2016. The series is set in the present day, while the one-off special features a Victorian period fantasy resembling the original Holmes stories.

Sherlock is produced by the Britthis network BBC, along with Hartswood Films, with Moffat, Gatiss, Sue Vertue and Rebecca Eaton serving as executive producers. The series is supported by the American station WGBH-TV Boston for its Masterpiece anthology series on PBS, where it also airs in the United States. The series is primarily filmed in Cardiff, Wales, with North Gower Street in London used for exterior shots of Holmes and Watson's 221B Baker Street residence.

Sherlock has been praised for the quality of its writing, acting, and direction. It has been nominated for numerous awards including Emmys, BAFTAs and a Golden Globe, winning several awards across a variety of categories. The show won in three categories at the 66th Primetime Emmy Awards including Outstanding Lead Actor in a Miniseries or a Movie for Cumberbatch, Outstanding Supporting Actor in a Miniseries or a Movie for Freeman and Outstanding Writing for a Miniseries, Movie or a Dramatic Special for Moffat.

Two years later, it won Outstanding Television Movie. In addition, the show was also honoured with a Peabody Award in 2011. The third series became the UK's most watched drama series since 2001. Sherlock has been sold to 180 territories. All of the series have been released on DVD and Blu-ray, alongside tie-in editions of selected original Conan Doyle stories and an original soundtrack composed by David Arnold and Michael Price. In January 2014, the show launched its official mobile app called Sherlock: The Network.

In January 2014, Moffat stated that a fifth series had peen plotted by himself and Gatiss; however, by the release of the fourth series in January 2017, they had not yet decided whether to produce it. Cumberbath and Moffat in particular have expressed interest in continuing at some point in the future, but there are no immediate plans. As to the future of the series, Gatiss stated that due to the conflicting schedules of Cumberbatch and Freeman, a potential fifth season is still up in the air.