Sergio Ribeiro Guevara (Ph.D.)

(Doctor en Ingeniería) - COLABORADOR. Divulgador científico. Ingeniero físico nuclear.

plants and nature

Mistakes we make with our trees

Improper placement of trees, either due to a lack of landscaping design or not considering their future growth, can both harm the tree and...

Statistics

What happens when the standard deviation is equal to zero?

The standard deviation of a data set or of a sample from a certain population is a descriptive statistical parameter that measures the spread...

Chemistry

Definition of acetate in chemistry; important for metabolism, but can cause hangovers

A common seasoning in our kitchens is vinegar. The typical sour taste and smell of different types of vinegars is due to acetic acid,...

Economy

What is a budget constraint?

In economics, the execution of a budget constraint is the first step in maximizing utility; that is, the way in which consumers get the...

Chemistry

What is the steric number?

The steric number is associated with a model that predicts the shape of polyatomic molecules or ions ; the theory of valence shell electron...

issues

The crimes of serial killer Gary Michael Hilton

On April 26, 2013, it was reported on the US news that “…a man previously convicted of killing and beheading hikers in Florida and...

History and culture

How was a pirate crew organized?

Piracy, that is, the attack and looting of boats and facilities, is an activity that dates back to antiquity and that still has some...

Statistics

What are moments in statistics?

Moments in calculations in statistics are concerned with determining parameters such as the mean, variance, or skewness of a probability distribution. The term moment...

Chemistry

Ten facts about carbon, the basis of the chemistry of life

Carbon is an essential element for life, as it is the main constituent of all organic compounds. It can be in elemental form, forming...

issues

Can your ancestry make you eligible to claim Irish citizenship?

In the mid-19th century, Ireland was part of the United Kingdom. Its economy was based on the production of potatoes , which was the...

History and culture

How was the Mayflower pact generated?

The Mayflower Compact was the first document of government of the Plymouth Colony, a settlement that England established in North America in 1620. The...

Literature

Torvald Helmer’s character in Henrik Ibsen’s A Doll’s House

A Doll's House is a play by Henrik Ibsen that premiered in 1879 and that poses a strong criticism of the established rules of...

biology

natural and artificial cloning

Cloning is the process of creating genetically identical copies of biological material. Cloning can reproduce both molecules, cells and tissues as well as whole...

geology

What is hornfels and how is it formed?

Hornfels, more commonly referred to as horn rock, is a very hard, fine-grained metamorphic rock. It is formed by the recrystallization of the original...

issues

Profile of death row inmate Brenda Andrew

Brenda Evers Andrew is on death row in Oklahoma convicted of the murder of her husband, Robert Andrew. As in the plots of classic...

Literature

Do you know Hermia and Aegeus, characters from “A Midsummer Night’s Dream”?

A Midsummer Night's Dream ( A Midsummer Night's Dream ) is a comedy by William Shakespeare written in the year 1595. The plot of...

Education

How educational scaffolding can improve understanding

The concept of scaffolding in education refers to the set of supports, guidance and information that a person receives throughout a learning process. Scaffolding...

For students and parents

Mnemonic Tools for Students

The mnemonic or mnemonic refers to the ways of memorizing based on mental associations of the information that one wants to remember; For this,...

Linguistics

Definition and Examples of Rhetorical Analysis

Rhetorical analysis, also called rhetorical criticism or pragmatic criticism, refers to the study of the influence of context on the interpretation of a text....

Statistics

The importance of the central limit theorem

The central limit theorem is a basic theorem in probability theory. The term "central" is equivalent to fundamental, or of central importance, and was...

Literature

Analysis of the short story “The Lottery” by Shirley Jackson

The Lottery ( The lottery ) is a short story written by Shirley Jackson and published in 1948 in the American newspaper The New...

History and culture

What are the 7 most famous “ninjas” in Japanese history?

The ninja or shinobi were warriors trained to spy and carry out covert actions in ancient Japan; these actions included assassination, sabotage, and guerrilla...

Physical

Specific Gravity Definition

Specific gravity or relative density of a substance is understood to be the relationship between its density and the density of a reference substance....

Architecture

Biography of Rem Koolhaas, Dutch Architect

Rem Koolhaas is a Dutch architect and urban planner renowned for his innovative designs. He was born in Rotterdam on November 17, 1944. He...

History and culture

What is the importance of the Mayan book known as the Popol Vuh?

The Popol Wuj, or Popol Vuh, a name that translates to "council book" or "community book", collects the Mayan legends that describe their worldview...

Arithmetic

How to Calculate a Percentage Change

It is common to find in daily life changes in values given by a percentage. A discount on the price of a product, or...

Economy

What is mathematical economics?

Mathematical economics is understood as the application of mathematical tools to represent theories , develop models, and analyze economic problems . Reference is made...

History and culture

Biography of Edmund Cartwright, English Inventor

Edmund Cartwright was born in Nottinghamshire, England, on April 24, 1743, and died in Sussex, also in England, on October 20, 1823. He was...

History and culture

Keys to understanding Jim Crow laws

The so-called Jim Crow laws were a set of state and local laws that in the United States maintained racial segregation since the late...

Geography

Are there famous geographers?

It is not popularly known that some famous people were geographers before becoming famous, as opposed to people who dedicated their lives to the...

Physical

What is the speed of light in miles per hour?

Let's see how to convert the speed of light to units of miles per hour. The speed of light in a vacuum is a...

issues

Traditional Russian games and how to play them

Games have long been an important part of Russian culture. Many games developed from pagan dances that predated Christianity. These traditional games were often...

Philosophy

What were the 5 great schools of ancient Greek philosophy?

The development of philosophy in ancient Greece extends from the 7th century BC to the 1st century. Five philosophical schools were generated during that...

Architecture

What are the characteristics of ancient monumental architecture?

The term monumental architecture refers to large man-made stone or earth structures that are used as public buildings or common spaces, as opposed to...

issues

Biography of Brian David Mitchell, kidnapper of Elizabeth Smart.

Brian David Mitchell and his wife, Wanda Barzee, kidnapped Elizabeth Smart on June 5, 2002. Elizabeth Smart was 14 years old at the start...

Literature

What gods and goddesses are characters in Homer’s “The Iliad”?

The Iliad is an epic poem that narrates the events that took place in the last year of the Trojan War. It is a...

Psychology

Three psychological explanations of deviant behavior

Deviant or antisocial behavior can be understood as any behavior that contrasts with the dominant norms of a society. There are several theories about...

Physical

How to convert pressure values from millibars to atmospheres

This article shows how to convert pressure values expressed in millibars (mbar) to atmospheres (atm). It is often necessary to convert the units between...

Literature

Frankenstein’s characters: descriptions and analysis

Frankenstein or the modern Prometheus ( Frankenstein; or, The Modern Prometheus ) is an epistolary novel by Mary Shelley published in 1818, which is...

Philosophy

The myth of Er from Plato’s “The Republic”

Plato was a Greek philosopher who lived between 427 and 347 BC. Founder of the Academy of Athens, student of Socrates and teacher of...

Physical

perfect inelastic collision

Unlike elastic collisions, inelastic collisions or inelastic collisions are those in which kinetic energy is lost in the event. This loss of kinetic energy...

issues

Meaning and origin of the name Maldonado

The surname Maldonado is of Spanish and Portuguese origin. It was a nickname used to indicate that a person was ugly or ignorant; It...

Physical

What is diffusion?

The diffusion of atoms and molecules in a certain medium, be it a gas, a liquid or a solid, is a physical process through...

History and culture

What were the intolerable laws?

The intolerable laws ( Intoleable Acts ) were a series of laws that the British Parliament promulgated in 1774 in response to the actions...

Economy

Definition of command economy: characteristics, advantages and disadvantages

In a command economy, also called a centrally planned economy or command economy, the central government controls all major aspects of the country's economy...

geology

What is breccia rock and what is it used for?

The breccia is a sedimentary rock formed by angled pieces of rock larger than two millimeters in size called clasts, joined by a natural...

Chemistry

12 things that really glow in the dark

Organisms, chemicals or various materials can produce light and glow in the dark. 12 cases are listed below. ...

biology

How do trees grow and develop?

Trees are usually present in our environment and are part of many of the landscapes that are common to us. But it is not...

Statistics

How to calculate the margin of error

In studies that use statistical tools, the results are presented including the margin of error, which is also called the confidence interval. Regardless of...

Sociology

Sutherland’s theory of differential association

Differential association theory proposes that social interactions provide values, attitudes, techniques, and even motivation for people to engage in criminal behavior. It is a...

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