New directions for the treatment of adrenal insufficiency

The following funding bodies supported this work: Biotechnology and Biological Sciences Research Council (BBSRC BB/L00267/1, to LG), Rosetrees Trust (to LG), Barts and The London Charity (417/2235, to LG), EU COFUND (PCOFUND-GA-2013-608765, to LG and GRB). IH is supported by a Medical Research Council (MRC, G0802796) PhD studentship

Weighing the Local Group in the Presence of Dark Energy

We revise the mass estimate of the Local Group (LG) when Dark Energy (in the form of the Cosmological Constant) is incorporated into the Timing Argument (TA) mass estimator for the Local Group (LG). Assuming the age of the Universe and the Cosmological Constant according to the recent values from the Planck CMB experiment, we find the mass of the LG to be M_TAL = (4.73 +- 1.03) x 10^{12} M_sun, which is 13% higher than the classical TA mass estimate. This partly explains the discrepancy between earlier results from LCDM simulations and the classical TA. When a similar analysis is performed on 16 LG-like galaxy pairs from the CLUES simulations, we find that the scatter in the ratio of the virial to the TA estimated mass is given by M_vir/M_TAL = 1.04 +-0.16. Applying it to the LG mass estimation we find a calibrated M_vir = (4.92 +- 1.08 (obs) +- 0.79 (sys)) x 10^{12} M_sun.Comment: 5 pages, 5 figures, Accepted for publication in MNRAS (Letters

Photochemical Electrocyclic Ring Closure and Leaving Group Expulsion from N-(9-oxothioxanthenyl)Benzothiophene Carboxamides

N-(9-Oxothioxanthenyl)benzothiophene carboxamides bearing leaving groups (LG− = Cl−, PhS−, HS−, PhCH2S−) at the C-3 position of the benzothiophene ring system photochemically cyclize with nearly quantitative release of the leaving group, LG−. The LG− photoexpulsions can be conducted with 390 nm light or with a sunlamp. Solubility in 75% aqueous CH3CN is achieved by introducing a carboxylate group at the C-6 position of the benzothiophene ring. The carboxylate and methyl ester derivatives regiospecifically cyclize at the more hindered C-1 position of the thioxanthone ring. Otherwise, the photocyclization favors the C-3 position of the thioxanthone. Quantum yields for reaction are 0.01–0.04, depending on LG− basicity. Electronic structure calculations for the triplet excited state show that excitation transfer occurs from the thioxanthone to the benzothiophene ring. Subsequent cyclization in the triplet excited state is energetically favourable and initially generates the triplet excited state of the zwitterionic species. Expulsion of LG− is thought to occur once this species converts to the closed shell ground state

The complexity of resolving conflicts on MAC

We consider the fundamental problem of multiple stations competing to transmit on a multiple access channel (MAC). We are given $n$ stations out of which at most $d$ are active and intend to transmit a message to other stations using MAC. All stations are assumed to be synchronized according to a time clock. If $l$ stations node transmit in the same round, then the MAC provides the feedback whether $l=0$, $l=2$ (collision occurred) or $l=1$. When $l=1$, then a single station is indeed able to successfully transmit a message, which is received by all other nodes. For the above problem the active stations have to schedule their transmissions so that they can singly, transmit their messages on MAC, based only on the feedback received from the MAC in previous round. For the above problem it was shown in [Greenberg, Winograd, {\em A Lower bound on the Time Needed in the Worst Case to Resolve Conflicts Deterministically in Multiple Access Channels}, Journal of ACM 1985] that every deterministic adaptive algorithm should take $\Omega(d (\lg n)/(\lg d))$ rounds in the worst case. The fastest known deterministic adaptive algorithm requires $O(d \lg n)$ rounds. The gap between the upper and lower bound is $O(\lg d)$ round. It is substantial for most values of $d$: When $d =$ constant and $d \in O(n^{\epsilon})$ (for any constant $\epsilon \leq 1$, the lower bound is respectively $O(\lg n)$ and O(n), which is trivial in both cases. Nevertheless, the above lower bound is interesting indeed when $d \in$ poly($\lg n$). In this work, we present a novel counting argument to prove a tight lower bound of $\Omega(d \lg n)$ rounds for all deterministic, adaptive algorithms, closing this long standing open question.}Comment: Xerox internal report 27th July; 7 page