Qualitative Assessment of General Aviation Pilots’ Perceptions of Preflight Weather Briefings

Prior to departing on a flight, General Aviation pilots complete a pre-flight planning process to ensure the safety of their flight. One aspect of the pre-flight planning process is obtaining a briefing on the weather conditions that the pilot might encounter along their flight route. Traditionally pilots have utilized a phone-in service run by Flight Services to aid in their assessment of weather conditions. However, research indicates that pilots are increasingly reliant on conducting self- briefing using online resources. The purpose of this study is to determine pilot perceptions of obtaining a phone-in brief in comparison to self-briefing

Combinatorial Intracellular Delivery Screening of Anticancer Drugs

Conventional drug solubilization strategies limit the understanding of the full potential of poorly water-soluble drugs during drug screening. Here, we propose a screening approach in which poorly water-soluble drugs are entrapped in poly(2-(methacryloyloxyethyl phosphorylcholine)-poly(2-(diisopropylaminoethyl methacryate) (PMPC–PDPA) polymersomes (POs) to enhance drug solubility and facilitate intracellular delivery. By using a human pediatric glioma cell model, we demonstrated that PMPC–PDPA POs mediated intracellular delivery of cytotoxic and epigenetic drugs by receptor-mediated endocytosis. Additionally, when delivered in combination, drug-loaded PMPC–PDPA POs triggered both an enhanced drug efficacy and synergy compared to that of a conventional combinatorial screening. Hence, our comprehensive synergy analysis illustrates that our screening methodology, in which PMPC–PDPA POs are used for intracellular codelivery of drugs, allows us to identify potent synergistic profiles of anticancer drugs

Sheath parameters for non-Debye plasmas: simulations and arc damage

This paper describes the surface environment of the dense plasma arcs that damage rf accelerators, tokamaks and other high gradient structures. We simulate the dense, non-ideal plasma sheath near a metallic surface using Molecular Dynamics (MD) to evaluate sheaths in the non-Debye region for high density, low temperature plasmas. We use direct two-component MD simulations where the interactions between all electrons and ions are computed explicitly. We find that the non-Debye sheath can be extrapolated from the Debye sheath parameters with small corrections. We find that these parameters are roughly consistent with previous PIC code estimates, pointing to densities in the range $10^{24} - 10^{25}\mathrm{m}^{-3}$. The high surface fields implied by these results could produce field emission that would short the sheath and cause an instability in the time evolution of the arc, and this mechanism could limit the maximum density and surface field in the arc. These results also provide a way of understanding how the "burn voltage" of an arc is generated, and the relation between self sputtering and the burn voltage, while not well understood, seems to be closely correlated. Using these results, and equating surface tension and plasma pressure, it is possible to infer a range of plasma densities and sheath potentials from SEM images of arc damage. We find that the high density plasma these results imply and the level of plasma pressure they would produce is consistent with arc damage on a scale 100 nm or less, in examples where the liquid metal would cool before this structure would be lost. We find that the sub-micron component of arc damage, the burn voltage, and fluctuations in the visible light production of arcs may be the most direct indicators of the parameters of the dense plasma arc, and the most useful diagnostics of the mechanisms limiting gradients in accelerators.Comment: 8 pages, 16 figure

The Indoor Radon Concentration within the Tunnels of the Cholula Pyramid Through a Nuclear Tracks Methodology

Global organizations, including the World Health Organization (WHO), the Environmental Protection Agency of the United States (US-EPA) and the European Atomic Energy Community (EURATOM) recognize that radon gas as one of the main contributors to environmental radiation exposure for humans. Accordingly, a study and analysis of the indoors radon concentrate in the Cholula Pyramid contributes to understand the Radon dynamic inside of the Pyramid tunnels and to evaluate the radiological health risk to visitors, archaeologists, anthropologists and persons who spend extended periods inside the Pyramid. In this paper, the radon measurements along the Pyramid tunnels are presented. The Nuclear Track Methodology (NTM) was chosen for the measurements, using a close end-cup device developed at the Dosimetry Application Project (DAP) of the Physics Institute UNAM, following very well established protocols for the chemical etching and reading with the Counting Analysis Digital Imaging System (CADIS). The Cholula Pyramid consists of eight stages of constructions, each built in different periods of time. Cholula Pyramid is recognized as the pyramid with the largest base in the World, with 400 meters per side and 65 meters high. The tunnels of the pyramid were built in 1931 by architect Ignacio Marquina, with the aim of exploring and studying the structure. The results show an important indoor radon concentration in the measured tunnels, several times higher than levels recommended by United States Environmental Protection Agency (US-EPA). The recommendation will be to mitigate the radon concentration levels, in order to avoid unnecessary exposition to the people

Analysis and characterization of neutron scattering of a Linear Accelerator (LINAC) on medical applications.

In several theoretical and experimental studies, the topic of the undesirable generation of photoneutrons in rooms where a linear accelerator (LINAC) operates has been discussed. When energies above 10 MeV are used to produce X-rays and give radiotherapy treatment to patients resulting in additional radiation to patients. Accordingly, an analysis and characterization of the neutron scattering distribution on different zones in a treatment room contributes to evaluate the radiological health risk to patients, technical and other workers involved in treatment. For the evaluation, a device developed at the PAD-IFUNAM formed by a CR-39 detector enclosed by two 3mm thick acrylic plates was employed. To avoid environmental contamination, the CR-39 and the acrylics plates are enclosed in a round plastic box. Sixteen of these devices were settled in different places inside the treatment room, where a linear accelerator is used. The results show a significant concentration of neutron scattering in areas near the head of irradiation. The recommendation will be to evaluate the neutron scattering concentration in all rooms that’s operates a LINAC in order to verify the radiological health risk and to mitigate the neutron scattering when concentration levels are to high like those in our case, in order to avoid unnecessary exposition to patients and personnel in general

Mild Regiospecific Synthesis of 1-Alkoxy-isochromenes Catalysed by Well-Defined [Silver(I)(Pc-L)] Complexes

The synthesis of 3-substituted-1-alkoxyisochromenes starting from 2-alkynylbenzaldehydes and different alcohols is reported. The reaction is catalysed by a silver(I)complex with an original macrocyclic pyridine-containing ligand (Pc-L). The approach is characterised by absolute regioselectivity, mild reaction conditions, good to excellent reaction yields, cleanness of the reaction and reduced purification steps. The reaction mechanism is investigated by in-depth 1H NMR experiments and an aimed \u201ctrapping\u201d experiment

Alkynylbenzaldehyde cyclizations catalyzed by Ag(I) complexes of chiral pyridine containing macroclyclic ligands (Pc-L*)

The tandem acetalization/cycloisomerization of ortho-alkynylbenzaldehydes, originally reported by Yamamoto using Pd(OAc)2 as a catalyst, gives 1H-isochromene derivatives that can have useful medicinal properties. Although several related tandem processes using different nucleophiles are known, no enantioselective version of this reaction has appeared until the very recent report by Slaughter and coworkers. Their study, published after we started our investigations, is based on the use of chiral gold(I) acyclic diaminocarbene complexes as catalysts in the presence of LiNTf2 (Tf=trifluoromethanesulfonyl) as a necessary additive to achieve useful activity. Recent studies in our research group demonstrated the efficacy of Cu(I) complexes derived from novel macrocyclic ligands containing a pyridine ring (Pc-L*) in the cyclopropanation reaction. The excellent results obtained up to now with copper prompted us to verify the application of silver(I) complexes of these ligands in catalysis. We herein report the synthesis of the new Ag(I) macrocyclic complexes, and their catalytic activity in the synthesis of oxygenated heterocycles by addition/cycloisomerization reactions of alcohols and ortho-alkynylbenzaldehydes

Minimal Gaugino Mediation

We propose Minimal Gaugino Mediation as the simplest known solution to the supersymmetric flavor and CP problems. The framework predicts a very minimal structure for the soft parameters at ultra-high energies: gaugino masses are unified and non-vanishing whereas all other soft supersymmetry breaking parameters vanish. We show that this boundary condition naturally arises from a small extra dimension and present a complete model which includes a new extra-dimensional solution to the mu problem. We briefly discuss the predicted superpartner spectrum as a function of the two parameters of the model. The commonly ignored renormalization group evolution above the GUT scale is crucial to the viability of Minimal Gaugino Mediation but does not introduce new model dependence.Comment: LaTeX, 16 pages, 4 figures, running of the bottom and tau Yukawas included, plots revise

Tandem Addition/Cycloisomerisation reactions catalyzed by [Ag(I)(Pc-L*)] complexes

The tandem emiacetalization/cycloisomerization of ortho-alkynylbenzaldehydes (Scheme 1), originally reported by Yamamoto using Pd(OAc)2 or CuI as a catalysts, gives 1H-isochromene derivatives that can have useful medicinal properties. Although several related tandem processes are known, no enantioselective version of this reaction has appeared until the very recent report by Slaughter and coworkers. Their study, is based on the use of chiral gold(I) acyclic diaminocarbene complexes as catalysts in the presence of LiNTf2 (Tf = trifluoromethanesulfonyl) as a necessary additive to achieve useful activity. Recent studies in our research group demonstrated the efficacy of Cu(I) complexes, derived from novel macrocyclic ligands containing a pyridine ring (Pc-L*), in cyclopropanation reactions.5 The excellent results obtained up to now with copper prompted us to verify the application of silver(I) complexes of these ligands in catalysis. We herein report the synthesis and characterization of the new Ag(I) macrocyclic complexes, 1 (Figure 1) and their catalytic activity in the synthesis of oxygenated heterocycles by addition/cycloisomerization reactions of alcohols and ortho-alkynylbenzaldehydes. Reactions are characterized by mild conditions, complete regioselectivity and 1H-isochromene derivatives are obtained in good to excellent yields starting from both electron rich and electron poor ortho-alkynylbenzaldehydes. When optically pure ligands are used, chiral induction in the reaction products is observed, although, up to now, with modest enantiomeric excesses

Modifying the Sum Over Topological Sectors and Constraints on Supergravity

The standard lore about the sum over topological sectors in quantum field theory is that locality and cluster decomposition uniquely determine the sum over such sectors, thus leading to the usual theta-vacua. We show that without changing the local degrees of freedom, a theory can be modified such that the sum over instantons should be restricted; e.g. one should include only instanton numbers which are divisible by some integer p. This conclusion about the configuration space of quantum field theory allows us to carefully reconsider the quantization of parameters in supergravity. In particular, we show that FI-terms and nontrivial Kahler forms are quantized. This analysis also leads to a new derivation of recent results about linearized supergravity.Comment: 17 pages, minor change