Shares are posting strong gains today as the spotlight moves from Europe's debt woes to the US, where traders are optimistic lawmakers will reach agreement on cutting the world's biggest economy's deficit.Chip companies ARM Holdings and Imagination Technologies in particular are taking their lead from the US, though for other reasons, jumping ahead after strong results from the California tech giant Apple, which uses their technology in its gadgets.Among UK stocks updating today, mining giant BHP Billiton is in demand after it achieved another iron ore output record in the year ended 30 June, its eleventh consecutive annual production record. The firm said that annual production records were achieved across four commodities and ten operations "as a result of our strategy to invest throughout the economic cycle."Fellow miners Lonmin, ENRC and Rio Tinto are also wanted.Drugs giant AstraZeneca fell after it (along with US peer Bristol-Myers Squibb) received a blow when the US Food and Drug Administration's (FDA) Advisory Committee rejected their jointly-developed diabetes drug, dapagliflozin, though the vote was a close one.Also in drugs, rattlesnake bite treatment maker BTG is licking its wounds a little despite reporting trading in line with expectations. Sales of CroFab, an antidote used to treat rattlesnake envenomation, and DigiFab, used to treat patients who have ingested too much of the foxglove plant extract digoxin, are "on budget", the company said, but Peel Hunt lowered its rating on the firm to "hold" from "buy."Advertising firm WPP is in demand, extending gains from yesterday when it announced that it had invested US$3m for a minority stake in Affectiva, a technology firm that specialises in measuring the emotional responses of consumers.London Stock Exchange (LSE) rose after the stock markets operator put behind it the disappointment of its failed merger with its Canadian counterpart TMX to announce a strong start to its financial year. "With an increase in total income of 14% and growth in many business areas, these strong first quarter results confirm that we continue to make good progress," said Xavier Rolet, the chief executive.Americas-focused silver and gold miner Hochschild Mining moved ahead after it said that it is on track to hit its production targets despite silver output falling by 13% in the first half. Hygiene technologies group Byotrol rocketed more than 50% after saying it has inked a potential multi-million pound contract to supply hand hygiene and surface sanitisation products to pest control services provider Rentokil Initial.FTSE 100 - RisersITV (ITV) 67.40p +4.09%Barclays (BARC) 219.90p +3.92%Royal Bank of Scotland Group (RBS) 34.34p +3.78%ARM Holdings (ARM) 604.00p +3.69%International Consolidated Airlines Group SA (IAG) 233.50p +2.91%Wolseley (WOS) 1,879.00p +2.62%BHP Billiton (BLT) 2,384.00p +2.49%Petrofac Ltd. (PFC) 1,489.00p +2.41%Eurasian Natural Resources Corp. (ENRC) 777.50p +2.37%RSA Insurance Group (RSA) 134.80p +2.35%FTSE 100 - FallersAstraZeneca (AZN) 2,977.00p -1.37%Sainsbury (J) (SBRY) 311.70p -1.36%ICAP (IAP) 466.00p -1.23%Imperial Tobacco Group (IMT) 2,116.00p -1.12%Glencore International (GLEN) 483.00p -1.09%Randgold Resources Ltd. (RRS) 5,470.00p -1.00%Shire Plc (SHP) 2,056.00p -0.87%Fresnillo (FRES) 1,650.00p -0.60%Morrison (Wm) Supermarkets (MRW) 293.00p -0.51%Autonomy Corporation (AU.) 1,698.00p -0.29%FTSE 250 - RisersImagination Technologies Group (IMG) 413.40p +8.68%Misys (MSY) 411.10p +7.79%AZ Electronic Materials SA (WI) (AZEM) 283.10p +4.12%IG Group Holdings (IGG) 449.80p +3.71%Enterprise Inns (ETI) 61.15p +3.64%Ladbrokes (LAD) 145.20p +3.64%Domino's Pizza UK & IRL (DOM) 461.00p +3.48%Punch Taverns (PUB) 70.50p +3.45%Hochschild Mining (HOC) 521.50p +3.37%Betfair Group (BET) 652.00p +3.16%FTSE 250 - FallersInternational Personal Finance (IPF) 329.80p -6.84%Daejan Holdings (DJAN) 2,821.00p -2.18%Dixons Retail (DXNS) 15.78p -2.17%BTG (BGC) 292.10p -1.98%Centamin Egypt Ltd. (CEY) 138.80p -1.56%COLT Group SA (COLT) 133.90p -1.54%Devro (DVO) 268.90p -1.50%Telecom Plus (TEP) 652.00p -1.21%Premier Foods (PFD) 20.34p -1.02%Euromoney Institutional Investor (ERM) 644.50p -0.92%