A reconciliation of the United States federal statutory corporate tax rate to the Company’s effective tax rate, or income tax provision, was as follows:



	Three-months Ended
	March 30, 2014		March 31, 2013
Income tax provision at federal statutory rate	35	%	35	%
State income taxes, net of federal benefit	1	%	2	%
Foreign tax rate differential	(17	)%	(17	)%
Tax credit	—	%	(1	)%
Discrete tax events	—	%	(3	)%
Income tax provision	19	%	16	%

The effective tax rate for the three-month period ended March 31, 2013 included a discrete event that decreased tax expense by $555,000, net of related reserves for income taxes, from the retroactive application of the 2012 research and development credit. The American Taxpayer Relief Act of 2012 was passed by Congress and signed into law on January 1, 2013. The provisions under this law were applied retroactively to January 1, 2012. As a result of the law being signed on January 1, 2013, the financial impact of the retroactive provision was recorded as a discrete event in the first quarter of 2013. This discrete tax event decreased the effective tax rate from a provision of 19% to a provision of 16% for the first quarter of 2013.

During the three-month period ended March 30, 2014, the Company recorded a $175,000 increase in reserves for income taxes, net of deferred tax benefit, for uncertain tax positions that were recorded as income tax expense. Estimated interest and penalties included in these amounts totaled $40,000 for the three-month period ended March 30, 2014.

In the first quarter of 2014, management adopted Accounting Standards Update (ASU) 2013-11, "Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists." This ASU requires companies to present an unrecognized tax benefit, or a portion thereof, as a reduction to a deferred tax asset for a net operating loss (NOL) carryforward or a similar tax loss or tax credit carryforward. During the three-month period ended March 30, 2014, the Company reclassified a reserve for income taxes of $1,028,000 as a reduction to noncurrent deferred tax assets in compliance with this new guidance. Retroactive application was not required under this ASU, and therefore, prior periods were not restated.

The Company’s reserve for income taxes, including gross interest and penalties, was $4,967,000 as of March 30, 2014, which included $3,939,000 classified as a noncurrent liability and $1,028,000 recorded as a reduction to noncurrent deferred tax assets. The amount of gross interest and penalties included in these balances was $415,000. If the Company’s tax positions were sustained or the statutes of limitations related to certain positions expired, these reserves would be released and income tax expense would be reduced in a future period, less $451,000 that would be recorded through additional paid-in capital. As a result of the expiration of certain statutes of limitations and the conclusion of an IRS examination, there is a potential that a portion of these reserves could be released, which would decrease income tax expense by approximately $700,000 to $800,000 over the next twelve months.

The Company has defined its major tax jurisdictions as the United States, Ireland, China, and Japan, and within the United States, Massachusetts and California. Within the United States, the tax years 2012 through 2013 remain open to examination by various taxing authorities, while the tax years 2009 through 2013 remain open to examination by various taxing authorities in other jurisdictions in which the Company operates.