Wednesday, March 18, 2020

Animal and Insect Blood That Isnt Red

Animal and Insect Blood That Isn't Red One fun Halloween chemistry project is making edible fake blood recipes. One of these recipes can be used to make blood in any color you like. Why colored blood? Blood comes in different colors, depending on species. While humans and many other species have red blood, due to the iron in their hemoglobin, other animals have different colored blood. Spiders (as well as horseshoe crabs and certain other arthropods) have blue blood due to the presence of copper-based hemocyanin in their blood. Some animals, such as the sea cucumbers, even have yellow blood. What could make blood yellow? The yellow coloration is due to a high concentration of the yellow vanadium-based pigment, vanabin. Unlike hemoglobin and hemocyanin, vanabin does not seem to be involved in oxygen transport. In addition to vanabin, sea cucumbers have enough hemocyanin in their blood to sustain their oxygen needs. Actually, the role of vanabin remains a bit of a mystery. Perhaps it is part of a defense mechanism to make the sea cucumbers unappealing or toxic to parasites and predators. However, sea cucumber is used for cooking in many cultures, where it is prized for its slippery texture and possible health benefits. Vanadium is a controversial dietary supplement, potentially affecting insulin sensitivity and athletic performance.

Monday, March 2, 2020

The Siege and Capture of San Antonio

The Siege and Capture of San Antonio In October-December of 1835, rebellious Texans (who referred to themselves as â€Å"Texians†) laid siege to the city of San Antonio de Bà ©xar, the largest Mexican town in Texas. There were some famous names among the besiegers, including Jim Bowie, Stephen F. Austin, Edward Burleson, James Fannin, and Francis W. Johnson. After about a month and a half of siege, the Texians attacked in early December and accepted the Mexican surrender on December 9. War Breaks out in Texas​ By 1835, tensions were high in Texas. Anglo settlers had come from the USA to Texas, where land was cheap and plentiful, but they chafed under Mexican rule. Mexico was in a state of chaos, having only won its independence from Spain in 1821. Many of the settlers, in particular, the new ones who were flooding into Texas daily, wanted independence or statehood in the USA. Fighting broke out on October 2, 1835, when rebellious Texians opened fire on Mexican forces near the town of Gonzalez. March on San Antonio San Antonio was the most important town in Texas and the rebels wanted to capture it. Stephen F. Austin was named commander of the Texian army and immediately marched on San Antonio: he arrived there with some 300 men in mid-October. Mexican General Martà ­n Perfecto de Cos, brother-in-law of Mexican President Antonio Là ³pez de Santa Anna, decided to maintain a defensive position, and the siege began. The Mexicans were cut off from most supplies and information, but the rebels had little in the way of supplies as well and were forced to forage. The Battle of Concepcià ³n On October 27, militia leaders Jim Bowie and James Fannin, along with some 90 men, disobeyed Austins orders and set up a defensive encampment on the grounds of the Concepcià ³n mission. Seeing the Texians divided, Cos attacked at first light the next day. The Texians were greatly outnumbered but kept their cool and drove off the attackers. The Battle of Concepcià ³n was a great victory for the Texians and did much to improve morale. The Grass Fight On November 26, the Texians got word that a relief column of Mexicans was approaching San Antonio. Led once again by Jim Bowie, a small squad of Texans attacked, driving the Mexicans into San Antonio. The Texians found out that it was not reinforcements after all, but some men sent out to cut some grass for the animals trapped inside San Antonio. Although the â€Å"Grass Fight† was something of a fiasco, it helped convince the Texians that the Mexicans inside San Antonio were getting desperate. Who Will Go with Old Ben Milam Into Bexar? After the grass fight, the Texians were indecisive about how to proceed. Most of the officers wanted to retreat and leave San Antonio to the Mexicans, many of the men wanted to attack, and still others wanted to go home. Only when Ben Milam, a cranky original settler who had fought for Mexico against Spain, declared â€Å"Boys! Who will go with old Ben Milam into Bexar?† did the sentiment for attack become the general consensus. The attack began early on December 5. Assault on San Antonio The Mexicans, who enjoyed vastly superior numbers and a defensive position, did not expect an attack. The men were divided into two columns: one was led by Milam, the other by Frank Johnson. Texan artillery bombarded the Alamo and Mexicans who had joined the rebels and knew the town led the way. The battle raged in the streets, houses and public squares of the city. By nightfall, the rebels held strategic houses and squares. On the sixth of December, the forces continued to fight, with neither making significant gains. The Rebels Get the Upper Hand On the seventh of December, the battle began to favor the Texians. The Mexicans enjoyed position and numbers, but the Texans were more accurate and relentless. One casualty was Ben Milam, killed by a Mexican rifleman. Mexican General Cos, hearing that relief was on the way, sent two hundred men to meet them and escort them into San Antonio: the men, finding no reinforcements, quickly deserted. The effect of this loss on Mexican morale was enormous. Even when reinforcements did arrive on the eighth of December, they had little in the way of provisions or arms and therefore were not much help. End of the Battle By the ninth, Cos and the other Mexican leaders had been forced to retreat to the heavily fortified Alamo. By now, Mexican desertions and casualties were so high that the Texians now outnumbered the Mexicans in San Antonio. Cos surrendered, and under the terms, he and his men were allowed to leave Texas with one firearm apiece, but they had to swear never to return. By December 12, all the Mexican soldiers (except for the most gravely wounded) had disarmed or left. The Texians held a raucous party to celebrate their victory. The Aftermath of the Siege of San Antonio de Bexar The successful capture of San Antonio was a big boost to the Texian morale and cause. From there, some Texans even decided to cross into Mexico and attack the town of Matamoros (which ended in disaster). Still, the successful attack on San Antonio was, after the Battle of San Jacinto, the rebels biggest victory in the Texas Revolution. The city of San Antonio belonged to the rebels...but did they really want it? Many of the leaders of the independence movement, such as General Sam Houston, did not. They pointed out that most of the settlers homes were in eastern Texas, far from San Antonio. Why hold a city they did not need? Houston ordered Bowie to demolish the Alamo and abandon the city, but Bowie disobeyed. Instead, he fortified the city and the Alamo. This led directly to the bloody Battle of the Alamo on March 6, in which Bowie and nearly 200 other defenders were massacred. Texas would finally gain its independence in April  1836, with the Mexican defeat at the battle of San Jacinto. Sources: Brands, H.W. Lone Star Nation: New York: Anchor Books, 2004.the Epic Story of the Battle for Texas Independence. Henderson, Timothy J. A Glorious Defeat: Mexico and its War with the United States.New York: Hill and Wang, 2007.