response to reviewer # 2

Abstract

The application of direct analysis in real-time mass spectrometry (DART-MS), which is finding increasing use in atmospheric chemistry, to two different laboratory model systems for airborne particles is investigated:(1) submicron C 3 -C 7 dicarboxylic acid (diacid) particles reacted with gas-phase trimethylamine (TMA) or butylamine (BA) and (2) secondary organic aerosol (SOA) particles from the ozonolysis of α-cedrene. The diacid particles exhibit a clear odd-even pattern in their chemical reactivity toward TMA and BA, with the odd-carbon diacid particles being substantially more reactive than even ones. The ratio of base to diacid in reacted particles, determined using known diacid-base mixtures, was compared to that measured by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), which vaporizes the whole particle. Results show that DART-MS probes ∼ 30 nm of the surface layer, consistent with other studies on different systems. For αcedrene SOA particles, it is shown that varying the temperature of the particle stream as it enters the DART-MS ionization region can distinguish between specific components with the same molecular mass but different vapor pressures. These results demonstrate the utility of DART-MS for (1) examining reactivity of heterogeneous model systems for atmospheric particles and (2) probing components of SOA particles based on volatility.

Radicalizing realist legitimacy

“…As Finlayson points out, historical study can demonstrate variation far more easily than it can establish constants. 57 Even if liberal states are currently the most powerful around the world, this was not always the case, and it might not be the case in the future either. Without a liberal hegemony, it might turn out that non-liberal political institutions are rather good at protecting their citizens from radical disadvantage.…”

“…Third, even if liberal states continue to pursue interventionist foreign policies around the world, it may turn out that they can only sustain this by increasing reliance on brute coercion directed at their own citizens. Given that many of the foreign interventions of liberal states have required mass propaganda campaigns in order to navigate the difficulty of winning over an increasingly 'casualty-averse' public, 59 it seems plausible to predict that any future interventions will require increasingly severe forms of statefriendly propaganda and information control in order to produce acceptance, or at least acquiescence. In other words, future liberal interventionist states are likely to find themselves violating the critical theory principle to an ever increasing degree.…”

“…Lorna Finlayson demonstrates that seemingly conservative aspects which dominate contemporary realist literature have only a contingent connection to realism, reflecting more closely the political convictions of authors than realist methodology. 10 I aim to show that Williams' theory of legitimacy is an example of a form of realism in which this connection can and should be broken.…”