The impermanent fate of massive stars in AGN disks

Stars are likely to form or to be captured in AGN disks. Their mass reaches an equilibrium when their rate of accretion is balanced by that of wind. If the exchanged gas is well mixed with the stellar core, this metabolic process would indefinitely sustain an "immortal" state on the main sequence (MS) and pollute the disk with He byproducts. This theoretical extrapolation is inconsistent with the super-solar {\alpha} element and Fe abundances inferred from the broad emission lines in active AGNs with modest He concentration. We show this paradox can be resolved with a highly-efficient retention of the He ashes or the suppression of chemical blending. The latter mechanism is robust in the geometrically-thin, dense, sub-pc regions of the disk where the embedded-stars' mass is limited by the gap-formation condition. These stars contain a radiative zone between their mass-exchange stellar surface and the nuclear-burning core. Insulation of the core lead to the gradual decrease of its H fuel and the stars' equilibrium masses. These stars transition to their post-main-sequence (PostMS) tracks on a chemical evolution time scale of a few Myr. Subsequently, the triple-{\alpha} and {\alpha}-chain reactions generate {\alpha} and Fe byproducts which are released into their natal disks. These PostMS stars also undergo core collapse, set off type II supernova, and leave behind a few solar-mass residual black holes or neutron starsComment: 17 pages, 7 figures, Accepted for publication in MNRA

Industry Perceptions on the Need of Green Skills in Agribusiness Vocational Graduates

One of the global issue trends in vocational education is greening to support the achievement of sustainable development. Industry as one of the main stakeholders of vocational schools needs to know their views regarding the skills of prospective workers they need. This study aims to identify industry perceptions on the necessity of green skills in agribusiness vocational graduates. Five elements of green skills studied here are environmental awareness, innovation skills, communication skills, adaptability, and management of waste.  A descriptive research design with quantitative approach was used in this research. Data was be gathered through a questionnaire involving fifty practitioners from various types of food industries. The result showed that the industry practitioners agreed that green skills is required by agribusiness vocational graduates. This finding can be used as a guide in integrating green skills into the agribusiness vocational curriculum by considering the skills most needed based on industry perceptions

Simulation-based Evaluation of Mobile Ad Hoc Network Routing Protocols: Ad hoc On-Demand Distance Vector, Fisheye State Routing, and Zone Routing Protocol

Mobile ad hoc network (MANET) is an infrastructure-less and decentralized network without any physical connections. Nodes are mobile, free to move, and independent of each other which makes routing a difficult task. Hence, a dynamic routing protocol is needed to make MANET reliable and function properly. Several routing protocols have been proposed with different working mechanisms and performance levels. Therefore, the performance study of those protocols is needed. This paper evaluates the performance of MANET routing protocols using simulation based experiments to observe the behavior of the network as the density of the nodes increases. The paper evaluates the performance of proactive (fisheye state routing), reactive (ad hoc on-demand distance vector), and hybrid (zone routing protocol) routing protocols in terms of the packet delivery fraction, average throughput, and average end-to-end delay. The simulations of protocols to analyze their performance in different conditions were performed using the network simulator 2 (NS 2)

New insights on Saturn's formation from its nitrogen isotopic composition

The recent derivation of a lower limit for the $^{14}$N/$^{15}$N ratio in Saturn's ammonia, which is found to be consistent with the Jovian value, prompted us to revise models of Saturn's formation using as constraints the supersolar abundances of heavy elements measured in its atmosphere. Here we find that it is possible to account for both Saturn's chemical and isotopic compositions if one assumes the formation of its building blocks at $\sim$45 K in the protosolar nebula, provided that the O abundance was $\sim$2.6 times protosolar in its feeding zone. To do so, we used a statistical thermodynamic model to investigate the composition of the clathrate phase that formed during the cooling of the protosolar nebula and from which the building blocks of Saturn were agglomerated. We find that Saturn's O/H is at least $\sim$34.9 times protosolar and that the corresponding mass of heavy elements ($\sim$43.1 \Mearth) is within the range predicted by semi-convective interior models.Comment: Accepted for publication in Astrophysical Journal Letter

High-Throughput and Accurate 3D Scanning of Cattle Using Time-of-Flight Sensors and Deep Learning

We introduce a high throughput 3D scanning solution specifically designed to precisely measure cattle phenotypes. This scanner leverages an array of depth sensors, i.e. time-of-flight (Tof) sensors, each governed by dedicated embedded devices. The system excels at generating high-fidelity 3D point clouds, thus facilitating an accurate mesh that faithfully reconstructs the cattle geometry on the fly. In order to evaluate the performance of our system, we have implemented a two-fold validation process. Initially, we test the scanner's competency in determining volume and surface area measurements within a controlled environment featuring known objects. Secondly, we explore the impact and necessity of multi-device synchronization when operating a series of time-of-flight sensors. Based on the experimental results, the proposed system is capable of producing high-quality meshes of untamed cattle for livestock studies

Children’s Schooling and Parents’ Behavior: Evidence From the Head Start Impact Study

Parents may have important effects on their children, but little work in economics explores whether children\u27s schooling opportunities crowd out or encourage parents\u27 investment in children. We analyze data from the Head Start Impact Study, which granted randomly chosen preschool-aged children the opportunity to attend Head Start. We find that Head Start causes a substantial increase in parents\u27 involvement with their children—such as time spent reading to children, math activities, or days spent with children by fathers who do not live with their children—both during and after the period when their children are potentially enrolled in Head Start

Effect of Moulding Temperature on Mechanical Properties of Pure Aluminum Sand Casting

In this study, mechanical properties (Tensile test, Brinell hardness and microstructure analysis) of pure aluminium after sand casting were investigated. Tensile test, Brinell hardness and microstructure analysis were performed using MAX text software, Universal Testing Machine and Escope with Clemax Imager, respectively. Sand cast aluminium was observed to have good tensile and hardness properties. From the observations, sand cast sample had uniform distribution of aluminium. &nbsp

High-levelexpression of functional recombinant human coagulation factor VII in insect cells

Abstract: Recombinant coagulation factor VII (FVII) is used as a potential therapeutic intervention in hemophilia patients who produce antibodies against the coagulation factors. Mammalian cell lines provide low levels of expression, however, the Spodoptera frugiperda Sf9 cell line and baculovirus expression system are powerful systems for high-level expression of recombinant proteins, but due to the lack of endogenous vitamin K-dependent carboxylase, expression of functional FVII using this system is impossible. In the present study, we report a simple but versatile method to overcome the defect for high-level expression of the functional recombinant coagulation FVII in Sf9 cells. This method involves simultaneous expression of both human γ-carboxylase (hGC) and human FVII genes in the host. It may be possible to express other vitamin K-dependent coagulation factors using this method in the future. Keywords: Baculovirus; γ-carboxylase; Coagulation FVII; Factor VII; Insect cel