Energy Prices and Induced Technological Progress

This study measures energy price induced technological change using directional distance function for a panel data of 55 countries over the period 1974 to 2000. The parameter estimates of directional distance function reveal the absence of neutral exogenous innovations and the presence of biased innovations either it is exogenous or energy price induced. We observe larger energy price induced technological change effects in developed countries in comparison to developing countries in the periods after first (1974), and second (1980) world oil crisis that caused substantial energy price increases. These findings concur with data that show most R&D occurs in high-income countries, particularly the US and Japan.

Energy Prices and Induced Technological Progress

This study measures energy price induced technological change using directional distance function for a panel data of 55 countries over the period 1974 to 2000. The parameter estimates of directional distance function reveal the absence of neutral exogenous innovations and the presence of biased innovations either it is exogenous or energy price induced. We observe larger energy price induced technological change effects in developed countries in comparison to developing countries in the periods after first (1974), and second (1980) world oil crisis that caused substantial energy price increases. These findings concur with data that show most R&D occurs in high-income countries, particularly the US and Japan.

Dual-acting stapled peptides target both HIV-1 entry and assembly

Background: Previously, we reported the conversion of the 12-mer linear and cell-impermeable peptide CAI to a cell-penetrating peptide NYAD-1 by using an i,i + 4 hydrocarbon stapling technique and confirmed its binding to the C-terminal domain (CTD) of the HIV-1 capsid (CA) protein with an improved affinity (Kd ~ 1 μM) compared to CAI (Kd ~ 15 μM). NYAD-1 disrupts the formation of both immature- and mature-like virus particles in in vitro and cell-based assembly assays. In addition, it displays potent anti-HIV-1 activity in cell culture against a range of laboratory-adapted and primary HIV-1 isolates.<p></p> Results: In this report, we expanded the study to i,i + 7 hydrocarbon-stapled peptides to delineate their mechanism of action and antiviral activity. We identified three potent inhibitors, NYAD-36, -66 and -67, which showed strong binding to CA in NMR and isothermal titration calorimetry (ITC) studies and disrupted the formation of mature-like particles. They showed typical α-helical structures and penetrated cells; however, the cell penetration was not as efficient as observed with the i,i + 4 peptides. Unlike NYAD-1, the i,i + 7 peptides did not have any effect on virus release; however, they impaired Gag precursor processing. HIV-1 particles produced in the presence of these peptides displayed impaired infectivity. Consistent with an effect on virus entry, selection for viral resistance led to the emergence of two mutations in the gp120 subunit of the viral envelope (Env) glycoprotein, V120Q and A327P, located in the conserved region 1 (C1) and the base of the V3 loop, respectively.<p></p> Conclusion: The i,i + 7 stapled peptides derived from CAI unexpectedly target both CA and the V3 loop of gp120. This dual-targeted activity is dependent on their ability to penetrate cells as well as their net charge. This mechanistic revelation will be useful in further modifying these peptides as potent anti-HIV-1 agents.<p></p&gt

The NxD-BMAP/G/1 queueing model : queue contents and delay analysis

We consider a single-server discrete-time queueing system with N sources, where each source is modelled as a correlated Markovian customer arrival process, and the customer service times are generally distributed. We focus on the analysis of the number of customers in the queue, the amount of work in the queue, and the customer delay. For each of these quantities, we will derive an expression for their steady-state probability generating function, and from these results, we derive closed-form expressions for key performance measures such as their mean value, variance, and tail distribution. A lot of emphasis is put on finding closed-form expressions for these quantities that reduce all numerical calculations to an absolute minimum