The phrase "a significantly positive effect" is correct and usable in written English.
You can use it to describe an effect that is notably beneficial in a particular situation or context. For example, "The introduction of the new policy had a significantly positive effect on employee morale."
The results indicated that salt hydrates are cost effective and have a significantly positive effect on the thermal behavior of prefabricated wooden houses.
Although restoration had a significantly positive effect on only two mire specialist butterflies (Boloria aquilonaris, Colias palaeno), it had a significantly positive effect on overall specialist species abundance.
Pernod Ricard said it expected synergy benefits of 125 million to 150 million euros before tax, with no impact on earnings per share in the first year after the purchase but a significantly positive effect thereafter.
In addition to gbM, gene length, expression level, expression breadth and gene duplicates retained from the α WGD were kept in our best model and all had a significantly positive effect on expression consistency (Table 2 and supplementary table S7).
It's certainly possible, and during the summer, at the height of my troubles, I was prescribed the antidepressant sertraline which after some initial discomfort (painful headaches, problems staying asleep), has had a significantly positive effect.
Second, we repeat the tests in Hall, Jaffe, and Trajtenberg (2005) with an augmented set of control variables and find that both the number of patents and the citations per patent have a significantly positive effect on firm value.
The results suggested that the implementation of DDR could have a significantly positive effect on children's self-efficacy, social support, and daily physical activity levels across time.
Although the incubation periods had little effect on DNA precipitation, the ethanol volumes and temperatures both had a significantly-positive effect on DNA yield rate obtained by precipitation (ethanol: F = 21.51, df = 2, P<0.01; temperature: F = 20.71, df = 2, P<0.01).
The washing of the solids was determined to not have an overall significantly positive effect on recycle performance.
The coefficients on the first set of control variables do not change much in size or sign compared to column 1. Age has a small and significantly positive effect on LOC, and mother's education seems to be an important determinant.
For the isomerization reaction, water addition in the reaction feed produced little effect on the catalysis of HZSM-5 but significantly positive effect on the catalysis of Nb2O5; the typical Lewis acidic γ-Al2O3 showed no activity for this reaction in either the presence or absence of water.
