Fromage

Un fromage est un aliment obtenu à partir de lait coagulé ou de produits laitiers, comme la crème, puis d'un égouttage suivi ou non de fermentation et éventuellement d'affinage (fromages affinés). Le fromage est fabriqué à partir de lait de vache principalement, mais aussi de brebis, de chèvre ou de bufflonne. Le lait est acidifié, généralement à l'aide d'une culture bactérienne. Une enzyme, la présure, ou un substitut comme par exemple de l'acide acétique ou du vinaigre, est ensuite adjointe afin de provoquer la coagulation et former le lait caillé et le petit-lait. Certains fromages comportent de la moisissure, soit sur la croûte externe, soit à l'intérieur, soit sur la croûte et à l'intérieur.
Des centaines de types de fromage sont produits dans le monde. Leurs différents styles, goûts et textures dépendent de l'origine du lait (y compris le régime alimentaire de l'animal), si le lait a été pasteurisé, du pourcentage de matière grasse, de l'espèce des bactéries et des moisissures choisis, du procédé de fabrication, ainsi que du temps de maturation. Des herbes, des épices, ou la fumaison peuvent être utilisées pour varier le goût.
Pour quelques fromages, le lait est caillé à l'aide d'un agent acide, comme du vinaigre ou du jus de citron. La plupart des fromages sont acidifiés à moindre degré à l'aide d'une bactérie transformant le lactose en acide lactique, le caillage étant assuré par l'ajout de présure.
Le fromage est un aliment de base, riche en graisses, protéines, calcium et phosphore à longue conservation en comparaison de la durée de conservation du lait à partir duquel il est fabriqué.

Définition administrative française

Un décret administratif du 27 avril 2007 définit le terme « fromage » comme étant réservé au « produit fermenté ou non, obtenu par coagulation du lait, de la crème ou de leur mélange, suivi d’égouttage ».
Les caractéristiques concernant l’extrait sec, la teneur en matière grasse et l’origine du lait, doivent figurer sur l’étiquetage.
Les fromages frais (fromages blancs, suisses, demi-sel…) sont riches en eau (70 à 82 %), et ne subissent pas d’affinage.
Le minimum de matière sèche, pour les fromages autres que frais, est fixé à 23 %.
Il est autorisé d'adjoindre un qualificatif au mot fromage : un « triple crème » contient au minimum 75 % de matière grasse ; un « double crème » en contient de 60 à moins de 75 % ; un « fromage gras », de 50 à moins de 60 % ; un « fromage allégé » (et sans addition de sucre) de 20 à moins de 30 % ; un « fromage maigre », moins de 20 %.
Les fromages fermiers sont exclusivement fabriqués avec le lait produit dans l’exploitation d’où ils proviennent. La mention « matière grasse non précisée » est alors admise.
La mention « au lait cru » est réservée aux fromages obtenus avec du lait dont la température n’a pas été portée au-delà de 40°C.
Depuis le 20 juin 1992 (décret du 19 février 1991), tous les fromages produits à la ferme, affinés, doivent comporter l’indication d’une date limite d’utilisation optimale (DLUO), et les fromages frais une date limite de consommation (DLC).

Global warming

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-twentieth century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 100 years ending in 2005.The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the temperature increase since the mid-twentieth century is "very likely" due to the increase in anthropogenic greenhouse gas concentrations, and natural phenomena such as solar variation and volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward. These basic conclusions have been endorsed by 30 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries.
Climate model projections indicate that global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. Increasing global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, likely including an expanse of the subtropical desert regions. Other likely effects include Arctic shrinkage and resulting Arctic methane release, shrinkage of the Amazon rainforest, increases in the intensity of extreme weather events, changes in agricultural yields, modifications of trade routes, glacier retreat, species extinctions and changes in the ranges of disease vectors.
Political and public debate continues regarding the appropriate response to global warming. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to reverse global warming. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.

Greenhouse effect

The causes of the recent warming are an active field of research. The scientific consensus is that the increase in atmospheric greenhouse gases due to human activity has caused most of the warming observed since the start of the industrial era, and the observed warming cannot be satisfactorily explained by natural causes alone. This attribution is clearest for the most recent 50 years, which is the period when most of the increase in greenhouse gas concentrations took place and for which the most complete measurements exist.
The greenhouse effect was discovered by Joseph Fourier in 1824 and first investigated quantitatively by Svante Arrhenius in 1896. It is the process by which absorption and emission of infrared radiation by atmospheric gases warm a planet's lower atmosphere and surface. Existence of the greenhouse effect as such is not disputed. The question is instead how the strength of the greenhouse effect changes when human activity increases the atmospheric concentrations of particular greenhouse gases.

Recent increases in atmospheric carbon dioxide (CO2). The monthly CO2 measurements display small seasonal oscillations in an overall yearly uptrend; each year's maximum is reached during the Northern Hemisphere's late spring, and declines during the Northern Hemisphere growing season as plants remove some CO2 from the atmosphere.
Naturally occurring greenhouse gases have a mean warming effect of about 33 °C (59 °F), without which Earth would be uninhabitable. On Earth the major greenhouse gases are water vapor, which causes about 36–70 percent of the greenhouse effect (not including clouds); carbon dioxide (CO2), which causes 9–26 percent; methane (CH4), which causes 4–9 percent; and ozone, which causes 3–7 percent.
Human activity since the industrial revolution has increased the atmospheric concentration of various greenhouse gases, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. The atmospheric concentrations of CO2 and methane have increased by 36% and 148% respectively since the beginning of the industrial revolution in the mid-1700s. These levels are considerably higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores.Less direct geological evidence indicates that CO2 values this high were last seen approximately 20 million years ago.Fossil fuel burning has produced approximately three-quarters of the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-use change, in particular deforestation.
CO2 concentrations are expected to continue to rise due to ongoing burning of fossil fuels and land-use change. The rate of rise will depend on uncertain economic, sociological, technological, and natural developments. The IPCC Special Report on Emissions Scenarios gives a wide range of future CO2 scenarios, ranging from 541 to 970 ppm by the year 2100.Fossil fuel reserves are sufficient to reach this level and continue emissions past 2100 if coal, tar sands or methane clathrates are extensively exploited.

Valentine's Day History

There are varying opinions as to the origin of Valentine's Day. Some experts state that it originated from St. Valentine, a Roman who was martyred for refusing to give up Christianity. He died on February 14, 269 A.D., the same day that had been devoted to love lotteries. Legend also says that St. Valentine left a farewell note for the jailer's daughter, who had become his friend, and signed it "From Your Valentine". Other aspects of the story say that Saint Valentine served as a priest at the temple during the reign of Emperor Claudius. Claudius then had Valentine jailed for defying him. In 496 A.D. Pope Gelasius set aside February 14 to honour St. Valentine.

Gradually, February 14 became the date for exchanging love messages and St. Valentine became the patron saint of lovers. The date was marked by sending poems and simple gifts such as flowers. There was often a social gathering or a ball.

In the United States, Miss Esther Howland is given credit for sending the first valentine cards. Commercial valentines were introduced in the 1800's and now the date is very commercialised. The town of Loveland, Colorado, does a large post office business around February 14. The spirit of good continues as valentines are sent out with sentimental verses and children exchange valentine cards at school.