Whenever a bloodlike stain is found at the scene of a crime, the forensic scientist must conduct two basic kinds of tests: presumptive and confirmatory. The reason presumptive tests are conducted first is because they are more cost-efficient than the more cumbersome confirmatory tests.
What is a presumptive test?
Presumptive tests for blood can be found in two broad categories: those that change color, and those that cause a glowing reaction.
Presumptive tests that depend on a color change involve the following:
Other tests depend on chemical reactions that cause blood to fluoresce, or glow, under an ultraviolet light source, uncovering blood that is invisible to the naked eye. Offenders many times try to scrub walls and floors clean, mistakenly taking for granted that if blood is not visible, it can not be found. Fortunately, that is not the case. At the scene of a crime, blood can show up by spraying a fluorescent chemical over the area suspected of containing blood. The lights are dimmed, and ultraviolet light is passed over the area, causing bloodstains to fluoresce in the dark just like you see on CSI. Not only is the presence of blood established, but the area of blood distribution is also clearly indicated. This is where blood spurts, drag marks, spatter, footprints, and handprints show up.
The actors you see on CSI use fluorescent chemicals to get the blood to reveal itself. The most common fluorescent chemicals used are luminol and fluorescein.
Teichmann and Takayama tests are the most commonly used confirmatory tests. Both tests depend on a chemical reaction between a reagent and hemoglobin. This reaction yields crystals, which then can be seen under a microscope. A considerable benefit of these tests is that they are more effective with aged stains.
The next time you watch your favorite forensic science/detective show like NCIS or CSI, you will have a clearer understanding of the chemicals used in exposing blood at a crime scene.
Now, are you ready for the REAL TRUTH about selling on eBay?
It's simple; don't list too many items for sale using their auction format. Instead, set up one of their stores. The cost starts at just $9.99 per month.
Why is this a good idea?
Let's do the math:
If you list an item for sale using the auction format, the cost is anywhere from $.35 on up to several dollars PER AUCTION. What's worse is that the auctions are only good for 3, 5, 7, or 10 days.
BETTER WAY: Sell the item in your eBay store. The listing price is just 2 or 3 cents per item...and get this...They're good for a FULL 30 days! For example, I recently sold a $500 item that I listed in my eBay store. The listing cost me a whopping 3 cents! The same item, if I'd sold it using the auction format, would have cost me several dollars!
Using eBay's Auction format to list 500 items at a minimum of $.35 each = $175.00 (and these are only good for 7 days each so you'd have to list them 4 times each per month) $175 x 4 = $700.00
List the same 500 items in your eBay store @ just $.03 each = $15 + the $9.99 monthly store fee = $24.99 and they are listed for a full 30 days each!
You save $675.01 per month! HOLY SMOKES!
I'm sure you can clearly see the benefit here. Of course you will want to sell a few CHEAP items using the auction format to try to generate interest & drive customers to your eBay store where they will buy MORE from you. Make sure every auction listing contains a link to your eBay store & TELL THE CUSTOMER TO VISIT YOUR STORE. Sell 10 or so of your 3 or 4 or หานักสืบ 5 dollar items as auctions...just enough to get some traffic to your store.
Now, what is it that the REALLY successful PowerSellers do?
They maximize the "back-end" sale.
What this means to you is that once a customer has bought from you, the hard part is over. Now having done business with you, they TRUST you to deliver the goods. You MUST & I REPEAT, MUST try to get that customer to buy again & again.
Never, ever, send a package to a customer without including a sales flyer, catalog or some other special offer in the package to try to entice them to make another purchase. Email them a special offer every week or so.
You NEED repeat customers. Going after the lone, one-time sale is a losing battle. You will not be successful unless you get them to buy again & again & do this with every person you deal with.
Send a thank-you note via postal mail or eMail to every customer & use that opportunity to SELL THEM SOMETHING ELSE.
Sell CONSUMABLE items. You know, stuff that people need to order fairly often. Like socks, t-shirts, work gloves, food items, towels & linens, printer ink cartridges, sell shipping materials to other eBay sellers. You will get REPEAT orders from these customers for months and even years to come.