I agree that ‘hard work’ does not precisely capture that which high morale systems reward. ‘Effort’ might be closer, but rewarding someone who is effortlessly friendly or effortlessly smart (when either is required for the job) would not hurt morale.
I would perhaps phrase it as the alignment of perceived incentives of the individuals to the goals of their employers. You get what you reward.
For example, a terrible workplace in which it is common knowledge that promotions are the result of having sex with your superior might seem low morale, but strictly speaking is not. Over time, you will attract a lot of people who are highly motivated. Specifically, motivated to have sex with their bosses and land cushy bullshit jobs. Naturally, for most organizations this is orthogonal to their mission, so as far as advancing the interests of the org are concerned, morale would be low, just as if promotions were assigned by lottery.
Most kidney stones are made out of calcium oxalate, which is a salt with a very low solubility.
However, the relationship between calcium and kidney stones is far from straightforward.
You consume oxalates in your food. If you are prone to kidney stones, the best thing you can do is to keep them in your digestive track rather than taking it up in your bloodstream (from where it will have to be excreted through the kidneys later). A good way to do that is to bind them into a salt with low solubility. Enter calcium oxalate, again.
So calcium in your digestive tract can reduce the risk of kidney stones: your body is still excreting the oxalates as calcium oxalate, but in the intestines there is no chance for crystals to grow over months, and your intestines have a much larger diameter than your ureters.
Still, a higher blood calcium level should lead to a higher risk of kidney stones. What is regulating the uptake of calcium again? As I learned from your article, the active vitamin D, metabolized out of the storage variant by the kidneys.
Now, it could be that the kidneys regulate the active variant in a perfect control circuit which does not depend on the blood level of the precursor (as long as it is high enough). But given that we are talking about messy biological systems, I think it is plausible that a higher supply of storage D will result in a higher level of blood calcium in equilibrium. (If you are on the brink of storage D deficiency, the proteins which produce the active form would not have to be inhibited by calcium very much. If storage D is plentiful, the mass action law (or whatever the protein equivalent is called) suggests that you will need a higher level of calcium to shut them off.)
The firstpaper I found on this topic suggests that there is some evidence that vitamin D supplements as well as calcium supplements taken between meals (when the calcium can’t protect you from the oxalates you ate with your food) increases the risk of kidney stones.