answer:To properly convert your default_scope to a lambda in Rails 4, you need to use the 'order' syntax with 'Arel.sql', like this: ```ruby default_scope -> { order(Arel.sql("external_updated_at DESC")) } ``` In this new syntax, `->` is used to define the lambda scope, and `order` is a method in ActiveRecord that sorts the result set. The `Arel.sql` method is used to handle string inputs that are expected to be SQL statements. Therefore, by wrapping `external_updated_at DESC` in `Arel.sql`, we allow the Rails engine to safely parse our default ordering statement., The correct syntax for using a lambda with `default_scope` in Rails 4 is as follows: ```ruby default_scope -> { order(external_updated_at: :desc) } ``` Here, we're passing a lambda (a block of code) to `default_scope` that returns an ActiveRecord relation with the records ordered by `external_updated_at` in descending order. The `order` method takes a hash with the column name as the key and the direction as the value (`:desc` for descending order). Note that we're using a symbol (`:external_updated_at`) instead of a string (`'external_updated_at'`) for the column name. This is because symbols are generally more efficient than strings in Ruby. Also, make sure to remove any trailing commas from your scopes, as they are no longer allowed in Ruby 1.9 and later versions.,To define the default_scope in Rails 4, you should use the following syntax: ```ruby class Ticket < ActiveRecord::Base default_scope -> { order(:external_updated_at) } end ``` In Rails 4, default_scope accepts a block, and you need to use a lambda (->) for scope(). The lambda is necessary because there are two parameters for default_scope: name and block. For example, if you have another scope called "red" that filters records with color 'red', you would define it as follows: ```ruby class Shirt < ActiveRecord::Base scope :red, -> { where(color: 'red') } end ``` Make sure to use this format when defining default_scope and other scopes in Rails 4.

answer:A plan to reduce electricity usage in a home can include a number of different strategies. These include replacing inefficient lightbulbs with energy-efficient LEDs, unplugging appliances and electronics when not in use, using natural light instead of electric lights where possible, using a touch-free faucet to reduce water heater use, using a smart thermostat to monitor and adjust temperatures automatically, installing a solar hot water heater, and turning off electronics when not in use. Additionally, making sure to install and seal windows and doors correctly to reduce air leakage can also help reduce electricity usage.,Reducing electricity usage in a home can be achieved through a combination of systemic changes in behavior and the implementation of energy-efficient technologies. Here's a ten-step plan that should help: 1. **Conduct an energy audit:** Begin by assessing your home's current energy use with an energy audit. This will help to understand where the main energy losses are and identify areas where you can focus on improvements. 2. **Switch to energy-efficient light bulbs:** Change traditional incandescent bulbs to LED bulbs. LED bulbs consume significantly less energy than conventional incandescent bulbs, are much longer-lasting and can reduce your overall electricity consumption. 3. **Unplug unused electronics:** Many devices drain power while in standby mode. To save energy, unplug or switch off devices when not in use. 4. **Use a power strip:** Consider using a power strip to control your electronics. When not in use, simply switch off the power strip. 5. **Use a programmable thermostat:** Automate heating and cooling in your home with a programmable thermostat, so that you don’t waste energy heating or cooling empty rooms. 6. **Invest in energy-efficient appliances:** When purchasing new appliances, choose energy-efficient models. Look for the ENERGY STAR label. 7. **Upgrade your insulation:** Ensuring proper insulation in your home can greatly reduce heating and cooling needs. Exterior walls, doors and windows can all benefit from insulation improvements. 8. **Use fans instead of air conditioning:** Opt for ceiling fans or portable fans during particularly stuffy conditions. Fans can provide a cooling breeze for a fraction of the energy cost of air conditioning. 9. **Open windows instead of heating or cooling**: During temperate days when conditions are just right, taking full advantage of natural airflow can help to save on electricity usage. 10. **Take shorter showers**: Showering uses a significant amount of hot water, which is usually heated electrically. Reducing shower time by a few minutes can lead to sizeable energy savings. Remember, these changes may seem small individually, but collectively, they can make a big difference in reducing your home's electricity consumption. Consider tracking your energy use over time to see how much you've reduced your usage., Sure, I'd be happy to help you develop a plan to reduce electricity usage in a home. Here are some steps you can take: 1. Conduct an energy audit: The first step in reducing electricity usage is to identify where you're using the most energy. You can hire a professional to conduct an energy audit, or you can do it yourself by examining your electricity bills, checking the wattage of your appliances, and looking for air leaks around windows and doors. 2. Use energy-efficient appliances: Replace old appliances with energy-efficient models. Look for the Energy Star label when purchasing new appliances, as this indicates that they meet strict energy efficiency guidelines set by the U.S. Environmental Protection Agency and the U.S. Department of Energy. 3. Adjust your day-to-day habits: Small changes in your daily routine can add up to big savings on your electricity bill. Here are some habits to consider: * Turn off lights and unplug electronics when not in use. * Use ceiling fans to circulate air and reduce the need for air conditioning. * Adjust your thermostat a few degrees lower in the winter and a few degrees higher in the summer. * Wash clothes in cold water and air-dry when possible. * Use energy-efficient LED light bulbs. * Cook with the smallest appliance possible (e.g., microwave instead of oven, toaster oven instead of stove). 4. Install a programmable thermostat: A programmable thermostat can help you save energy by automatically adjusting the temperature in your home when you're away or sleeping. 5. Seal air leaks: Sealing air leaks around windows, doors, and walls can help keep your home insulated and reduce the need for heating and cooling. Use caulk, weatherstripping, or spray foam to seal any gaps or cracks. 6. Insulate your home: Adding insulation to your attic, walls, and floors can help keep your home warm in the winter and cool in the summer, reducing the need for heating and cooling. 7. Install energy-efficient windows: If your windows are old or poorly insulated, consider replacing them with energy-efficient models. 8. Use renewable energy sources: Consider installing solar panels or a wind turbine to generate your own electricity. This can help reduce your reliance on the grid and lower your electricity bills. 9. Monitor your energy usage: Keep track of your electricity usage and look for ways to reduce it over time. You can use a smart plug or energy monitor to track your usage and identify areas where you can improve. By implementing these steps, you can significantly reduce your electricity usage and lower your energy bills. Additionally, you'll be reducing your carbon footprint and contributing to a more sustainable future.

answer:Sure, here is a simple function in Python to calculate the factorial of a given number: ```python def factorial(n): if n == 0: return 1 else: return n * factorial(n-1) ``` This function uses recursion. It keeps calling itself with smaller and smaller values until it reaches the base case (when `n` equals 0), at which point it returns 1. The product of all these returned values gives the final result. Please note that this function does not handle negative inputs or non-integer inputs. If you need to calculate factorials for such inputs, you would need a more complex approach.,Sure! Below is an example of a Python function that calculates the factorial of a given number: ```python def factorial(n): if (n == 0): return 1 else: return n * factorial(n-1) ``` In this function, it recursively multiplies a number (`n`) by all the positive integers less than or equal to `n`. The base case when `n` is 0, the factorial is returned as 1. It is a great example of an recursive approach to solving a factorial problem.,e! Here's one way to write a function to calculate the factorial of a given number in Python: ```python def factorial(n): # Base case if n <= 1: return 1 # Recursive case else: return n * factorial(n-1) # Example: Calculate the factorial of 5 num = 5 print(f"The factorial of {num} is {factorial(num)}") ``` This function uses recursion, which means that it calls itself until the base case (n <= 1) is reached. When the base case is reached, the function returns 1. Otherwise, the function will continue to call itself, multiplying n by the factorial of (n-1) at each call, until the base case is reached.

answer:he is solving the problem.,She is solving the problem., She is solving the problem. (Active voice) In the active voice, the subject of the sentence performs the action. Here, the subject "she" is performing the action "is solving." In the original sentence, "the problem" is the subject, which receives the action "is being solved" in the passive voice.