Current News Science & Technology

Sun Has Begun A New Solar Weather Cycle


The Solar Cycle 25 Prediction Panel, an international group of experts co-sponsored by NASA and National Oceanic and Atmospheric Administration (NOAA), announced that solar minimum occurred in December 2019, marking the start of a new solar cycle i.e. Solar Cycle 25.

What is Solar Cycle?

  • Our Sun is a huge ball of electrically-charged hot gas. This charged gas moves, generating a powerful magnetic field. The Sun's magnetic field goes through a cycle, called the solar cycle.Every 11 years or so, the Sun's magnetic field completely flips. This means that the Sun's north and south poles switch places. Then it takes about another 11 years for the Sun’s north and south poles to flip back again.This is called solar cycle.

Tracking Solar Cycles through Sunspots

  • The solar cycle affects activity on the surface of the Sun, such as sunspots which are caused by the Sun's magnetic fields. As the magnetic fields change, so does the amount of activity on the Sun's surface.
  • One way to track the solar cycle is by counting the number of sunspots. The beginning of a solar cycle is a solar minimum, or when the Sun has the least sunspots. Over time, solar activity—and the number of sunspots—increases.
  • The middle of the solar cycle is the solar maximum, or when the Sun has the most sunspots. As the cycle ends, it fades back to the solar minimum and then a new cycle begins.

Effects of Solar Cycle

  • Giant eruptions on the Sun, such as solar flares and coronal mass ejections, also increase during the solar cycle. These eruptions send powerful bursts of energy and material into space.
  • This activity can have effects on Earth. For example, eruptions can cause lights in the sky, called aurora, or impact radio communications. Extreme eruptions can even affect electricity grids on Earth.

Prediction of Space Weather

  • Some cycles have maximums with lots of sunspots and activity. Other cycles can have very few sunspots and little activity. Scientists work hard to improve our ability to predict the strength and duration of solar cycles. These predictions can help them forecast these solar conditions, called space weather.
  • Forecasting of the solar cycle can help scientists protect our radio communications on Earth, and help keep satellites and astronauts safe, too.

Current News International WHO

‘Serial Interval’in Managing COVID-19


According to a recent research paper published in the journal Science - China, which has now gone over a month without any locally transmitted Covid-19 cases, was able to contain Covid-19 due to its ability to manage the ‘serial interval’.

About ‘Serial Interval’

  • The serial interval is the duration between symptom onset of a primary case and symptom onset of secondary cases (contacts) generated by the primary case.
  • In simple terms, the serial interval is the gap between the onset of Covid-19 symptoms in Person A and Person B, who is infected by Person A.
  • Serial intervals can vary widely, especially for some lifelong diseases (HIV infection, Chickenpox, Herpes).
  • The serial interval for SARS was 7 days.
  • For COVID-19, a review of the published literature shows serial interval estimates to be 4-8 days

History

  • The term was first used by British physician William Pickles, who had initially referred to it as transmission interval with reference to a hepatitis epidemic in the United Kingdom during 1942-45.
  • Later, another British physician RE Hope Simpson used the term serial interval, defining it as the interval between successive illness onsets.

Factors on which Serial Interval Depends

The serial interval depends on other epidemiological parameters such as the incubation period, which is the time between a person’s exposure to the virus and symptom onset, and the reproduction rate or R naught, the number of people who will be infected by one infected person.

Source: Springer link

Significance

  • The serial interval helps to gauge the effectiveness of infection control interventions besides indicating rising population immunity and forecast future incidence.
  • Thus, the more quickly persons who contracted Covid-19 are identified and isolated, the shorter the serial interval becomes and cuts down opportunities for transmission of the virus.
  • To manage serial interval, a robust system of contact tracing, quarantine, and isolation protocols should be in place.

Examples

China

  • The serial interval in Wuhan came down from 7.8 days to 2.6 days between early January and early February.
  • Quarantining contacts within 1 day from symptom onset helped reduce Covid-19 transmission by 60 per cent.

South Korea

  • The serial interval in South Korea was estimated to be 3.63 days.
  • This was made possible due to aggressive contact tracing, quarantine, and isolation, thereby ensuring that infected patients, because they were isolated, could not infect any more people later in the infection cycle.
  • Other interventions such as suspension of intra- and intercity travel, and different forms of social distancing widely implemented in different Chinese cities kept the serial interval low.