I have the following code to create a `plot`. On the `x`- and `y-axes` there are `symbols` that appear on the screen, in a `JPEG` when I save my plot in that format, but not when I save the plot as a `PDF`.

Is there alternative symbol to my `\u2030` that will print in my PDF or another solution to my problem? See examples below of the correct (JPEG format) and the incorrect (PDF) plots .

```
plot(c(-1,1), c(-1,1), bty = "n", type= "n", las = 1, cex.lab = 1.5, cex.axis = 1.25, main = NULL, 
ylab=expression(paste("Correlation Coefficient (r) for ", delta ^{15},"N"," \u0028","\u2030","\u0029")), 
xlab=expression(paste("Correlation Coefficient (r) for ", delta ^{13},"C"," \u0028","\u2030","\u0029")))
axis(1, at = seq(-1.0, 1.0, by = 0.1), labels = F, pos = 0, cex.axis = 0.05, tcl = 0.25)
axis(2, at = seq(-1.0, 1.0, by = 0.1), labels = F, pos = 0, cex.axis = 0.05, tcl = 0.25)

```

![enter image description here](https://i.stack.imgur.com/BqY0w.jpg)
![enter image description here](https://i.stack.imgur.com/1VP9B.png)