If you were a college administrator, would you ban the use of tobacco products on campus?

Amid carefree talk of starting lineups, one public notice to the Sanford Stadium crowd on a recent Saturday stood out: Beginning Oct. 1, the University of Georgia will be among the academic institutions in this state that prohibit tobacco products from its campuses.

At the 31 public colleges and universities that make up the University System of Georgia, smoking will be forbidden. The use of chewing tobacco could lead to a penalty. And even products that “simulate the use of tobacco,” including e-cigarettes, are scheduled for banishment.

But of all the questions that complement the new regulations, the one that seems to loom largest here centers on the extent to which the University of Georgia should enforce the ban. Officials in Atlanta talk of a vigorous campaign to eliminate tobacco from campuses that thousands of people visit each day, but students openly doubt that administrators will impose sanctions on violators, and many predict the ban will be ignored and defied.

“Hypothetically, yes, it’d be nice to have a tobacco-free world,” said Beni Kozen, a junior, who nursed a cigarette before a physics test on a recent afternoon. “But sometimes you just need a study break and a stress-relief break.”

The restrictions will take effect as a rising number of colleges across the country rush to lay down new limits on tobacco use. In October 2010, according to the lobbying group Americans for Nonsmokers’ Rights, fewer than 450 colleges had enacted smoking bans. By Wednesday, that number will have increased to nearly 1,500, with most of those schools having prohibited all forms of tobacco.

Some campuses in Georgia had restrictive tobacco rules in place before the Board of Regents decided this year to take action at all of the state’s public colleges and universities, which enrolled more than 294,000 students last spring.

“It goes back to health and productivity,” said Marion Fedrick, the university system’s vice chancellor of human resources. “We’re not at all saying that they can’t smoke. They just can’t smoke on our campuses.”

The regents empowered university presidents to design their own plans for the restrictions, which are administrative in nature, meaning students who violate them are not subject to criminal prosecution.

Although the presidents have leeway, Ms. Fedrick said the regents “are 100 percent expecting this to be implemented,” and state officials plan audits to evaluate compliance.

At the University of Georgia, where a narrower policy has long included prohibitions on smoking within 35 feet of building entrances and campus bus stops, officials are advertising the planned restrictions with signs that sometimes feature a picture of Uga IX, the English bulldog that is the university’s mascot.

“We’re taking the approach of a positive educational campaign, not an enforcement campaign,” said Thomas H. Jackson Jr., a university spokesman. “We’re not even using the word ‘ban.’ It’s ‘prohibited.’ It’s not going to be a gotcha campaign.”

There is no definitive playbook, experts said, for how forcefully to apply tobacco restrictions once they are enacted. But many colleges begin with lax enforcement regimes.

“We really encourage campuses to have that phase-in process and have a lot of education,” said Tad Spencer, the director of tobacco prevention initiatives for Naspa, a national student affairs organization. “It’s not just an immediate jump-in.”

Many colleges, Mr. Spencer said, have spent up to a year prodding students toward compliance before they begin aggressively enforcing the rules against tobacco use on campus.

By that time, many students have accepted the new standards. At Framingham State University in Massachusetts, which banned tobacco last year, the dean of students said she had received no complaints this semester from students about the regulations.

“People who have been here all along are adapting to a change, and secondly, the people choosing to come here know the policy,” said the dean, Melinda K. Stoops, whose university west of Boston had about 6,400 students last fall.

But she conceded that challenges remain.

“Is our campus 100 percent smoke-free? No. You’ll still find someone violating the policy,” she said. “Is it dramatically different? Yes.”

At Georgia, there is also no unanimity about how the university should proceed or whether the ban should have ever been enacted.

Some students contend that the effects of smoking in public merit sweeping action.

“No one wants to be walking behind someone and have to breathe in their secondhand smoke,” said Alexa Karen, a pre-veterinary student who is from Marlboro, N.J.

But Ms. Karen and two of her friends, asked whether they thought the ban would make a difference, had a simple, simultaneous reply: “No.”

Should the U.S. government tax carbon emissions and carbon content in products and services to limit carbon-dioxide emissions causing climate change?

President Obama stood in the chamber of the United Nations General Assembly last week and urged the world to follow his example and fight global warming. But a major new declaration calling for a global price on carbon — signed by 74 countries and more than 1,000 businesses and investors — is missing a key signatory: the United States.

The declaration, released by the World Bank the day before Mr. Obama’s speech at the United Nations Climate Summit, has been signed by China, Shell, Dow Chemical and Coca-Cola. It calls on all nations to enact laws forcing industries to pay for the carbon emissions that scientists say are the leading cause of global warming.

The United States, which is under growing international pressure to price carbon, is missing from the declaration for a key reason: conservative opposition to Mr. Obama’s climate change proposals, specifically a carbon tax. The opposition will only intensify if Republicans win control of the Senate in November and the new majority leader is Senator Mitch McConnell of Kentucky, where coal — the world’s largest source of carbon pollution — is the lifeblood of the state’s economy.

“It’s time for the global elites to face facts,” Mr. McConnell said in a statement. “President Obama’s war on coal won’t have any meaningful impact on global carbon emissions. What it will do is ship American jobs overseas, raise the cost of living substantially for middle and working-class families and throw thousands more Kentuckians out of work.”

Although the nonbinding World Bank declaration is meant largely as a show of resolve ahead of a 2015 climate summit in Paris, it signals the broadest, most explicit effort to date of world leaders and financial institutions to push all nations to enact new taxes on old forms of energy. The declaration notes that governments can either directly tax carbon pollution or create market-based cap-and-trade systems, which force companies to buy government-issued pollution permits.

“The most powerful move that a government can make in the fight against climate change is to put a price on carbon,” said Rachel Kyte, the World Bank’s vice president of sustainability.

To many Republicans on Capitol Hill, such statements are anathema. In 2010, after Mr. Obama tried but failed in the face of conservative opposition to push a national cap-and-trade bill through Congress, victorious Republicans galvanized against the idea and launched campaigns against politicians who support carbon pricing. Mr. Obama in turn circumvented Congress and in June released a new Environmental Protection Agency regulation under his executive authority that requires states to submit their own plans to cut emissions — but does not tell them explicitly how to do so. Nonetheless, California and nine northwestern states have already enacted cap-and-trade programs, and seven states — California, Maryland, Massachusetts, Oregon, Rhode Island, Vermont and Washington — signed on to the World Bank declaration.

In order to avoid more opposition from conservatives, Mr. Obama and other top administration officials no longer call publicly for a national price on carbon. But they have nonetheless signaled their support for international and state efforts. In his speech at the United Nations, Mr. Obama quoted the Democratic governor of Washington, Jay Inslee, who is urging other states to pass carbon pricing laws: “As one of America’s governors has said, ‘We are the first generation to feel the impact of climate change and the last generation that can do something about it.’ ”

The Obama administration has also enacted a policy signaling its readiness to price carbon should the politics of Congress ever shift: a metric it calls “the social cost of carbon,” designed to account for the cost of one ton of carbon dioxide pollution. Mr. Obama’s economists have determined the cost to be $37 a ton. Secretary of State John Kerry, a longtime advocate of government policy to fight climate change — and the chief author of the failed 2010 cap-and-trade bill in the Senate — last week told a meeting of the Major Economies Forum that “when it comes to climate change, we know exactly what it takes to get the job done.”

But Mr. Kerry did not specifically mention carbon pricing at the forum, a gathering of foreign ministers of the world’s 20 largest economies, and said only, “It takes energy policy.”

About 40 countries have already implemented carbon pricing policy, while dozens of others are now exploring it. In 2005, the European Union enacted a cap-and-trade plan for carbon pollution, and at the United Nations last week, European leaders pushed hard for the rest of the world to sign on.

“We need to define a new economy of the world,” President François Hollande of France said in his remarks at the climate summit. “There will have to be a new pricing system for carbon.”

The weekend before the summit, more than 300,000 people protested at a climate change demonstration in the streets of New York, where marchers waved signs reading “Tax carbon!”

The new carbon pricing push comes as countries and institutions that once fought the idea are now embracing it.

“On carbon pricing, there’s a perfect storm taking place,” said Robert N. Stavins, director of the environmental economics program at Harvard. “There is increasing recognition that approaches that have been taken in the past haven’t worked, and that the only way one can affect the hundreds of millions of decisions is through price signals.”

Over the last year China has enacted seven pilot cap-and-trade programs in its provinces, although outside experts remain skeptical of Beijing’s plans as the nation’s carbon emissions continue to rise.

At the same time, the political power of the coal industry to fight such laws remains potent. Australia, a major coal-producing nation, offers a case study in the political dangers of supporting a carbon tax in a coal-heavy democracy. A former Australian prime minister, Julia Gillard, made tackling climate change a signature issue and enacted a carbon tax — a move that was seen as political suicide. Last year Australians voted her out of office and this past summer, the new prime minister, Tony Abbott, pushed through a bill to repeal the carbon price.

What would you do if you were a U.S. branch bank employee and realized that your boss was allowing the transfer of billions of dollars on behalf of countries blacklisted by the United States, including Sudan and Iran?

The chairman of BNP Paribas, France’s largest bank, is stepping down as the institution seeks to move beyond the fallout from its guilty plea and nearly $9 billion in fines in the United States for its dealings with blacklisted countries.

The chairman, Baudouin Prot, 63, will leave on Dec. 1 after more than 30 years with the bank, the board said in a statement late Friday. His departure was widely expected. He will be replaced by Jean Lemierre, a former head of the European Bank for Reconstruction and Development.

Before he became chairman three years ago, Mr. Prot was chief executive from 2003 to 2011. He is credited with helping guide BNP Paribas through the global financial crisis and into the ranks of the world’s biggest banks.

Mr. Prot’s reign, however, may ultimately be remembered more for the landmark criminal case brought by prosecutors and regulators in Washington and New York after the bank was accused of illegally transferring billions of dollars on behalf of countries blacklisted by the United States, including Sudan and Iran.

While other major banks, including Standard Chartered and HSBC, have been caught up in such affairs, the United States authorities were particularly incensed that BNP had ignored warnings and then refused to cooperate with the investigation.

After months of stormy negotiations, in which the French government lobbied on the bank’s behalf, BNP agreed in June to plead guilty and pay $8.9 billion in fines to settle the case, the largest such judgment ever.

Recent news reports that Mr. Prot would resign indicated it was his choice to leave. In its statement, the board lauded his leadership, saying it was “grateful to Baudouin Prot for his total commitment during the financial crisis of 2007-2011.”

The statement did not mention the American investigation.

BNP reported net profit last year of 4.8 billion euros, or $6.1 billion.

If you were a manager, how would you respond to an employee who, soon after converting to Islam, posts on Facebook messages that are critical of American culture and offers dire warnings to those who do not follow Islam? What precautionary steps, if any, would you take if you terminated this employee knowing that he has a criminal record for multiple assaults?

A man beheaded a co-worker at a food processing company in Oklahoma on Thursday afternoon, and stabbed another employee before he was shot and wounded by a company executive, the police said Friday.

The suspect, identified as Alton Nolen, who has a criminal history, had just been fired from the company, Vaughan Foods, and “he recently started trying to convert some of his co-workers to the Muslim religion,” said Jeremy Lewis, a spokesman for the police department in Moore, Okla. It was not immediately clear if that proselytizing was a reason for his termination.

After being fired, “he drove to the front of the business, running into a vehicle, exited his vehicle, entered the business, where he encountered the first victim, Colleen Hufford, and began assaulting her with a knife,” Mr. Lewis said. “He did kill Colleen and did sever her head.”

After killing Ms. Hufford, 54, he attacked Traci Johnson, 43, with the same knife, the police said.

“Mark Vaughan, who is the chief operating officer of Vaughan Foods and is also an Oklahoma County reserve deputy, confronted Nolen, and at that time shot him and stopped the threat and the assault,” Mr. Lewis said.

Mr. Nolen, 30, was convicted in 2011 of multiple drug charges, assault and battery on a police officer, and escape from detention, according to the Oklahoma Department of Corrections. He had earlier arrests on drug and assault charges.

Mr. Nolen was taken to Oklahoma University Medical Center and is expected to survive. He has not been charged. He and Ms. Johnson were both listed in stable condition.

The Moore police called in the F.B.I. to assist in the investigation. After the United States began its bombing campaign against the Islamic State in Syria on Monday, the F.B.I. and the Department of Homeland Security put out an alert to local law enforcement officials across the country to be on the watch for so-called lone wolves who might respond violently.

A law enforcement official said the F.B.I. had not found any connection between Mr. Nolen and the Islamic State, also known as ISIS, or other groups. “It’s not a typical workplace response, and given the current environment it is very alarming and is something we are closely looking into,” one of the officials said. “So far, there is no nexus to terrorism we are aware of.”

Law enforcement officials said Mr. Nolen recently converted to Islam. On a Facebook page that appears to be his, references to Islam began in April 2013, and he called himself Jah’Keem Yisrael. The page is filled with criticism of American culture, and dire warnings for those who do not follow that religion.

“This is the last days,” he wrote in his most recent post, on Tuesday. In another, in July, he wrote: “AMERICA AND ISRAEL ARE WICKED. WAKE UP MUSLIMS!!!”

Mr. Nolen grew up in Idabel, Okla., and in elementary school he often had extended absences, bouncing from family member to family member, a former friend, Ryan Impson, recalled. At Idabel High School, where the main pursuits were fishing and playing sports for the Idabel Warriors, he said, Mr. Nolen seemed like a normal teenager who played defense on the football team and was a shot-putter on the track team.

“He wasn’t into getting into trouble,” said Mr. Impson, an engineer who said he lost track of Mr. Nolen years ago. “He just did his work. We always joked around. He wasn’t an outcast, he didn’t cause problems, he wasn’t a troublemaker or anything like that.”

The police learned of the attack while it was still underway, at 4:05 p.m. on Thursday, from a 911 call from inside the plant. “We have someone attacking someone in the building,” a man, remaining remarkably clear and calm, told the 911 operator, a recording of the call showed. “They’re in the front office of the building. We can hear a lot of screaming.” Between telling someone else to close and lock a door, the man said: “We know that he’s loose. He has stabbed someone.” Then gunshots can be heard in the background.

Mr. Lewis, the police spokesman, said Mr. Vaughan “is obviously a hero in this situation” and saved Ms. Johnson’s life. “This guy definitely was not going to stop,” Mr. Lewis said. “He didn’t stop until he was shot. He was still assaulting Traci whenever he was shot.”

It appeared that Mr. Nolen had no relationship with either victim, he said.

“It did appear random,” Mr. Lewis said. “He wasn’t targeting anyone, wasn’t going specifically after them. It appears they were just in his way as he came in.”