'this first requires' is correct and usable in written English.
You can use it when you want to emphasize that one condition or element needs to be met before anything else can occur. For example: "To make this cake, this first requires two cups of flour."
Obviously, since our method relies on an estimate (hat {x}(n)) of the transmitted signal, this first requires some channel estimation.
This first requires getting to know us better.
This first requires to compute the expectation and covariance matrix of frequencies and then to study the derivative of a function which is specific of the method used to compute the pattern statistics.
This first requires raising awareness regarding timely and skilled attendance of delivery, clean delivery, thermal care of the newborn, hygiene, appropriate cord care, early initiation of and optimal breastfeeding and appropriate care for low birth weight.
This first requires us – as policymakers, industry actors, scholars, citizens, and consumers – to acknowledge not only medical tourism's imbrication in a broader range of transnational care pursuits and provision but also medical tourism's articulation in a broader (and increasingly global) political economy of health care.
This first requires us to establish the adjacency of 2 V n genotype pairs, followed by application of standard graph theory algorithms such as breadth-first search [ 21, 44] to compute whether genotypes decompose into two or more disconnected components, or whether they form a single connected network, i.e., whether a path through V(n) exists connecting any two genotypes [ 21].
Solving this problem first requires designing a device that can manipulate the fragile molecule without shredding it.
Solving this problem first requires the designing of a device that can manipulate the fragile molecule without shredding it.
This process first requires the rapid adsorption of a lipolytic enzyme, gastric lipase, onto the membrane enveloping the triglyceride substrate before the onset of catalytic activity.
This method first requires co-precipitation of magnesium and aluminum nitrate solution with sodium hydroxide in methanol, followed by LDH slurry collection and re-suspension in methanol.
However, taking advantage of redundant probe sets in this way first requires a careful examination of probe set quality and annotations.
