The heart is a muscular organ found in humans and other animals. This organ pumps blood through the blood vessels. Heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum.
In humans, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.
The heart pumps blood with a rhythm determined by a group of pacemaker cells in the sinoatrial node. These generate an electric current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart. In humans, deoxygenated blood enters the heart through the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here, it is pumped into pulmonary circulation to the lungs, where it receives oxygen and gives off carbon dioxide. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation, traveling through arteries, arterioles, and capillaries—where nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxide—before being returned to the heart through venules and veins. The adult heart beats at a resting rate close to 72 beats per minute. Exercise temporarily increases the rate, but lowers it in the long term, and is good for heart health.
Cardiovascular diseases are the most common cause of death globally as of 2008, accounting for 30% of all human deaths. Of these more than three-quarters are a result of coronary artery disease and stroke. Risk factors include: smoking, being overweight, little exercise, high cholesterol, high blood pressure, and poorly controlled diabetes, among others. Cardiovascular diseases do not frequently have symptoms but may cause chest pain or shortness of breath. Diagnosis of heart disease is often done by the taking of a medical history, listening to the heart-sounds with a stethoscope, as well as with ECG, and echocardiogram which uses ultrasound. Specialists who focus on diseases of the heart are called cardiologists, although many specialties of medicine may be involved in treatment.
The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This curve divides all viewing directions based on whether it intersects the relevant body's surface or not.
The true horizon is a theoretical line, which can only be observed to any degree of accuracy when it lies along a relatively smooth surface such as that of Earth's oceans. At many locations, this line is obscured by terrain, and on Earth it can also be obscured by life forms such as trees and/or human constructs such as buildings. The resulting intersection of such obstructions with the sky is called the visible horizon. On Earth, when looking at a sea from a shore, the part of the sea closest to the horizon is called the offing.
The true horizon surrounds the observer and it is typically assumed to be a circle, drawn on the surface of a perfectly spherical model of the relevant celestial body, i.e., a small circle of the local osculating sphere. With respect to Earth, the center of the true horizon is below the observer and below sea level. Its radius or horizontal distance from the observer varies slightly from day to day due to atmospheric refraction, which is greatly affected by weather conditions. Also, the higher the observer's eyes are from sea level, the farther away the horizon is from the observer. For instance, in standard atmospheric conditions, for an observer with eye level above sea level by 1.8 metres (6 ft), the horizon is at a distance of about 4.8 kilometres (3 mi).
When observed from very high standpoints, such as a space station, the horizon is much farther away and it encompasses a much larger area of Earth's surface. In this case, the horizon would no longer be a perfect circle, not even a plane curve such as an ellipse, especially when the observer is above the equator, as the Earth's surface can be better modeled as an oblate ellipsoid than as a sphere.
A smartwatch is a portable wearable computer that resembles a wristwatch. Most modern smartwatches are operated via a touchscreen, and rely on mobile apps that run on a connected device (such as a smartphone) in order to provide core functions.
Early smartwatches were capable of performing basic functions like calculating, displaying digital time, translating text, and playing games. More recent models often offer features comparable to smartphones, including apps, a mobile operating system, Bluetooth and Wi-Fi connectivity, and the ability to function as portable media players or FM radios. Some high-end models have cellular capabilities, allowing users to make and receive phone calls.
While internal hardware varies, most smartwatches have a backlit LCD or OLED electronic visual display and are powered by a rechargeable lithium-ion battery. They may also incorporate GPS receivers, digital cameras, and microSD card readers, as well as various internal and environmental sensors such as thermometers, accelerometers, altimeters, barometers, gyroscopes, and ambient light sensors. Some smartwatches also function as activity trackers and include body sensors such as pedometers, heart rate monitors, galvanic skin response sensors, and ECG sensors. Software may include maps, health and exercise-related apps, calendars, and various watch faces.
With or WITH may refer to:
- With, a preposition in English
- Carl Johannes With (1877–1923), Danish doctor and arachnologist
- With (character), a character in D. N. Angel
- With (novel), a novel by Donald Harrington
- With (album), a 2014 album by TVXQ
- With (EP), a 2021 EP by Nam Woo-hyun
Withings (pronounced "Wy-things" (en.) or "Wee-things" (fr.)) is a French consumer electronics company headquartered in Issy-les-Moulineaux, France. It also has offices in Boston, Massachusetts, USA, and Hong Kong, and distributes its products worldwide. Withings is known for design and innovation in connected devices, such as the first Wi-Fi scale on the market (introduced in 2009), an FDA-cleared blood pressure monitor, a smart sleep system, and a line of automatic activity tracking watches. It also provides B2B services for healthcare providers and researchers.
Withings was purchased by Finnish company Nokia on 26 April 2016 and became a division of Nokia known as Nokia Health. The Withings brand continued to be used until June 2017, when it was replaced by the Nokia brand. In May 2018, Éric Carreel, Withings' founder, finalized a deal to regain control and the company became independent again, under the Withings name.
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