<?xml version="1.0" encoding="UTF-8"?>
<!--XBRL Document Modified with Ez-Viewer Version 1.0.5.8 on Thursday, October 04, 2012 05:40:56 PM -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll"/>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#RiskReturn" roleURI="http://xbrl.sec.gov/rr/role/RiskReturn"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskReturn">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#ShareholderFeesData" roleURI="http://xbrl.sec.gov/rr/role/ShareholderFeesData"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/ShareholderFeesData">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#OperatingExpensesData" roleURI="http://xbrl.sec.gov/rr/role/OperatingExpensesData"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/OperatingExpensesData">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#ExpenseExample" roleURI="http://xbrl.sec.gov/rr/role/ExpenseExample"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/ExpenseExample">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#ExpenseExampleNoRedemption" roleURI="http://xbrl.sec.gov/rr/role/ExpenseExampleNoRedemption"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/ExpenseExampleNoRedemption">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#BarChartData" roleURI="http://xbrl.sec.gov/rr/role/BarChartData"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/BarChartData">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#PerformanceTableData" roleURI="http://xbrl.sec.gov/rr/role/PerformanceTableData"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceTableData">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#RiskReturnDetailData" roleURI="http://xbrl.sec.gov/rr/role/RiskReturnDetailData"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskReturnDetailData">
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#SeriesOnly" roleURI="http://xbrl.sec.gov/rr/role/Series"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/Series">
<loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain"/>
<loc xlink:type="locator" xlink:href="amstx-20120928.xsd#amstx_S000004767Member" xlink:label="loc_amstx_S000004767Member"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain" xlink:to="loc_amstx_S000004767Member" use="optional" order="0"/>
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#ClassOnly" roleURI="http://xbrl.sec.gov/rr/role/Class"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/Class">
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#rr_ShareClassDomain" xlink:label="loc_rr_ShareClassDomain"/>
<loc xlink:type="locator" xlink:href="amstx-20120928.xsd#amstx_C000012960Member" xlink:label="loc_amstx_C000012960Member"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_rr_ShareClassDomain" xlink:to="loc_amstx_C000012960Member" use="optional" order="0"/>
</definitionLink>
<roleRef xlink:type="simple" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#PerformanceMeasureOnly" roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasure"/>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasure">
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/rr/2010/rr-2010-02-28.xsd#rr_PerformanceMeasureDomain" xlink:label="loc_rr_PerformanceMeasureDomain"/>
<loc xlink:type="locator" xlink:href="amstx-20120928.xsd#amstx_Sp500IndexMember" xlink:label="loc_amstx_Sp500IndexMember"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_rr_PerformanceMeasureDomain" xlink:to="loc_amstx_Sp500IndexMember" use="optional" order="20"/>
</definitionLink>
</linkbase>
