Adherence to Selected Air Carrier (Airline) Operational Regulations for Improved General Aviation Flight Safety in Degraded Visibility

Introduction: General aviation largely comprises fixed-wing piston-engine light aircraft (,12,500 lbs). Unfortunately, this civil aviation sector suffers a vastly inferior safety record when compared with air carriers (60- to 80-fold higher accident rate). Additionally, such mishaps pose a considerable financial burden to both the affected family and the United States: US$1.64–4.64 billion annually. We hypothesize that this safety disparity partly reflects more stringent operational regulations for air carriers. Herein, we determined whether compliance with six selected air carrier regulations could potentially reduce general aviation accidents in degraded visibility (IMC) the majority of which are fatal. Methods: Accidents (2005–2019) were identified from the National Transportation Safety Board Access database. Fleet data for rate calculations were per the general aviation survey and the Bureau of Transportation Statistics. Statistics used Poisson distributions. Results: Of 219 general aviation accidents in IMC, 43 (20%) could potentially have been averted had one, or more, of the selected air carrier regulations been complied with. The largest percentage (62%) of the 43 mishaps were due to pilots operating contrary to the air carrier regulation specifying takeoff or landing weather minimums. The second largest group related to more conservative weather minimums required for an inexperienced airline pilot-in-command, eschewed in 19% of preventable general aviation IMC mishaps. Conclusions: Alignment with the aforementioned air carrier operational rules could potentially blunt the IMC accident rate (by 20%) for general aviation. Practical Applications: Adherence to the aforementioned air carrier regulations should be advocated to general aviation pilots operating in IMC

The nucleolus directly regulates p53 export and degradation

Nucleoli directly regulate p53 export and degradation rather than simply sequestering p53 regulatory factors

The Baryon Isgur-Wise Function in the Large NcN_c Limit

In the large $N_c$ limit, the $\Lambda_b$ and $\Lambda_c$ can be treated as bound states of chiral solitons and mesons containing a heavy quark. We show that the soliton and heavy meson are bound in an attractive harmonic oscillator potential. The Isgur-Wise function for $\Lambda_b\rightarrow\Lambda_c\, e^-\,\bar\nu_e$ decay is computed in the large $N_c$ limit. Corrections to the form factor which depend on $m_N/ m_Q$ can be summed exactly ($m_N$ and $m_Q$ are the nucleon and heavy quark masses). We find that this symmetry breaking correction at zero recoil is only $1\%$.Comment: 18 pages, 0 figures, uses harvma

Systematic study of the 87^{87}Sr clock transition in an optical lattice

With ultracold $^{87}$Sr confined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to-date of the $^1S_0$ - $^3P_0$ optical clock transition with a detailed analysis of systematic shifts (20 Hz uncertainty) in the absolute frequency measurement of 429 228 004 229 867 Hz. The high resolution permits an investigation of the optical lattice motional sideband structure. The local oscillator for this optical atomic clock is a stable diode laser with its Hz-level linewidth characterized across the optical spectrum using a femtosecond frequency comb.Comment: 4 pages, 4 figures, 1 tabl

Calcium and Zinc Ion Release from Polyalkenoate Cements Formed from Zinc Oxide/apatite Mixtures

Calcium and zinc ion release from hydroxyapatite-zinc oxide-poly (acrylic acid) (HAZnO-PAA) composite cements into deionised water was investigated as a function of HA content, PAA concentration, PAA molecular weight and maturation time. At any given maturation time, zinc ion release was constant until the HA content was at the maximum loading (60 wt%) resulting in the cement matrix breaking up, allowing exacerbated ion release. The calcium ion release increased with increased HA content in the composite until the maximum loading where the release drops off. Up to this point, the release of both ionic species was proportional to square root time for the initial 24-hour period, indicating that the release is diffusion controlled. In agreement with related data from conventional Glass Polyalkenoate Cements (GPCs), it is the concentration of the PAA, not the molecular weight, that influences ion release from these materials. However, unlike GPCs, the release of the active ions results in a pH rise in the deionised water, more conventionally seen with Bioglass® and related bioactive glasses. It is this pH rise, caused by the ion exchange of Zn2+ and Ca2+ for H+ from the water, leaving an excess of OH-, that should result in a favourable bioactive response both in vitro and in-vivo. © Springer Science + Business Media, LLC 2006

Glycosylation of Mouse DPP4 Plays a Role in Inhibiting Middle East Respiratory Syndrome Coronavirus Infection

Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes dipeptidyl peptidase 4 (DPP4) as an entry receptor. Mouse DPP4 (mDPP4) does not support MERS-CoV entry; however, changes at positions 288 and 330 can confer permissivity. Position 330 changes the charge and glycosylation state of mDPP4. We show that glycosylation is a major factor impacting DPP4 receptor function. These results provide insight into DPP4 species-specific differences impacting MERS-CoV host range and may inform MERS-CoV mouse model development

Cascading Globalization and Local Response: Indian Fishers’ Response to Export Market Liberalization

Scholars have long debated whether trade liberalization has positive or negative effects on resource use and ecosystems. This study examines the conditions under which resource use increases or decreases in response to reduced trade barriers, specifically after the 2008 World Trade Organization decision that led the United States to reduce anti-dumping duties on Indian shrimp. At the district level in South India, fishing fleet expansion was correlated with access to global market information via mobile phones. Model simulations indicate that increased mobile phone saturation could expand fish- ing effort sufficiently to deplete multiple marine species groups, while other species benefit from the loss of predators. However, scenario analysis suggests that regulatory interventions could mitigate these ecosystem pressures while still permitting fishers to benefit from increased access to global market information

Characterisation of Ga2O3-Na2O-CaO-ZnO- SiO2 Bioactive Glasses

The structural role of Gallium (Ga) is investigated when substituted for Zinc (Zn) in a 0.42SiO2-0.40-xZnO-0.10Na2O-0.08CaO glass series, (where x = 0.08). Each starting material was amorphous, and the network connectivity (NC) was calculated assuming Ga acts as both a network modifier (1.23), and also as a network former. Assuming a network forming role for Ga the NC increased with increasing Ga concentration throughout the glass series (Control 1.23, TGa-1 2.32 and TGa-2 3.00). X-ray photoelectron spectroscopy confirmed both composition and correlated NC predictions. Raman spectroscopy was employed to investigate Q-structure and found that a shift in wavenumbers occurred as the Ga concentration increased through the glass series, from 933, 951 to 960 cm-1. Magic angle spinning nuclear magnetic resonance determined a chemical shift from -73, -75 to -77 ppm as the Ga concentration increased, supporting Raman data. These results suggest that Ga acts predominantly as a network former in this particular Zn-silicate system. © 2013 Springer Science+Business Media New York

Eroding Potentiometers

Eroding potentiometers have been devised for measuring the time-dependent positions of char fronts advancing through layers of insulating material subject to intense heating from one side. In the original application, the material layers of interest are thermal insulators in rocket motors and the heat comes from firing of the motors, but the principle of operation is equally applicable to other insulating materials subject to intense heating (e.g., ablative fire-retardant materials). Measuring the thickness decrement of propellant (in hybrid motors in particular) is another possible application of this transducer. Telemetry informs mission control of the propellant left after each burn. An eroding potentiometer could be characterized, more precisely, as an eroding two-wire resistor. It includes a twisted pair of thin, insulated wires oriented along the thickness of, and embedded in, the layer of thermal-insulation material to be tested (see figure). The electrical insulation material on the wires should be one for which the charring temperature is about the same as (or perhaps slightly less than) that of the thermal- insulation material to be tested. In the original rocket-motor application, the wires have a diameter of 0.003 in. (.0.08 mm), are made of manganin, and are coated with polyimide for electrical insulation. Outside the thermal insulation on the cold side, the wire leads are connected to a Wheatstone bridge circuit for measurement of electrical resistance change