Yahoo! Acquires del.icio.us

Today, Yahoo! acquired del.icio.us, the social bookmarking service. Here are the respective blog entries: Yahoo! Searchblog and the del.icio.us blog. Stuart Maxwell, Jeff Barr, and Yahoo! team's Jeremy Zawodny recently did an interview explaining "What's so cool about del.icio.us", in which Jeremy gave a non-committal answer about Yahoo acquiring del.ico.us

Jet Skids Off Runway Killing Boy

In Chicago, a Southwest Airlines jet skidded off the runway Thursday evening while trying to land. It went into a street and killed a 6-year-old boy in a car. Ten other people were injured most of them on the ground.

In Situ Hybridization

ISH (In situ hybridization) uses a complementary strand of DNA to localize a specific DNA sequence in a tissue or onto a specific location on a chromosome. ISH is possible because of DNA's ability to hybridize, or anneal, to its complementary strand at the correct temperature. The DNA probe is fluorescently label (Fluorescent in situ hybridization or FISH) or it may be detected through autoradiography if the probe is radioactively labelled.

Process
Sample cells are treated to increase their permeability and allow the hybribization of the probe. A complmentary probe is created with a radioactive or fluorescent label. The probe is added to the treated cells and allowed to hybridize; excess probe is washed away. Autoradiography, immunochemistry, or fluorescence microscopy is used to detect the probe's location.

Applications
ISH can be used to determine the structure, function, and evolution of chromosomes. It is used in chromosomal gene mapping or to determine the expression of genes.

Death by SMS

In a new twist to careless drivers on cellphones, a 17-year-old hit a bicyclist while text messaging. The bicyclist, Jim Price, died two days after the accident. The teen could face up to one year in prison for careless driving resulting in death.

Creating Tables in Blogger

Tables in Blogger need to be put entirely on one line:

<table><tr><td>a</td></tr><tr><td>b</td></tr></table>

Otherwise, Blogger inserts a <br> for each line in your table above the table.

McNemar's Test

McNemar's test is is a non-parametric method used on nominal data to determine whether the row and column marginal frequencies are equal. It is named after McNemar, Q., who introduced it in 1947. Given 2 x 2 contingency table with a dichotomic trait with matched pairs of subjects.
In the following example, a researcher attempts to determine if a disease is associated with the presence of a particular gene. Individuals without the disease are controls and individuals with the disease are cases. Within the cases and controls, individuals with the hypothesized disease gene are marked as positive for the presence of the gene and individuals without the gene are marked as negative.

		Controls
		+	-	total
Cases	+	101	59	160
	-	121	33	154
	totals	222	92	314

The cells can be represented in the following manner by the letters a, b, c and d, The totals across rows and columns marginal totals, and the grand total is represented by n:

		Controls
		+	-	total
Cases	+	''a''	''b''	''a''+''b''
	-	''c''	''d''	''c''+''d''
	totals	''a''+''c''	''b''+''d''	''n''

Marginal homogeneity occurs when the row totals are equal to the column totals, a and d in each equation can be cancelled; leaving b equal to c:

(a + b) = (a + c)
(c + d) = (b + d)

The McNemar statistic is shown below:

χ² = (b − c)² / (b + c)
χ² is a chi-squared statistic with the df = 1. The formula may be re-written to correct for discontinuity:

χ² = ( | b − c | − 1)² / (b + c)
The marginal frequencies are not homogenous, if the the χ² result is significant p < 0.05. If b and/or c are small, (b + c) < 10, χ² is not approximated by the chi-square distribution instead a Fisher's exact test should be used.

Move Along, Nothing To See

NBC failed to tell viewers that two sisters, aged 11 and 26, had been injured by the M&M's float in the Macy's Thanksgiving Day Parade. Instead NBC showed footage of the float from last year, and the hosts stuck with their given scripts. Macy's offered the sisters VIP tickets to next year's parade.