The volume of air traffic in the National Air Space has been growing at a very fast pace during recent years, and increasing demand for air travel in coming years is predicted. Strategic Planning is a necessary tool to guarantee a safe and efficient increase of Air Traffic. An Aggregate Model for Strategic Planning of Air Traffic Management is the framework of this project.

Aggregate models require the creation of a network that is representative of the expected flow and which will serve as a platform to solve flow optimization problems. We have integrated an automatic method for route clustering - Smax method - to generate the required network. Automatic clustering is necessary in order to efficiently cluster many individual scenarios.

Some available alternatives to determine the number of clusters are tested. The studied alternatives provide success rates that oscillates between 49% and 68%. In addition to the relatively low success rates, these methods require one user-input parameter, and they are highly sensitive to it.

A different method, based on the Silhouette Score and the Dip Test measures, is developed. The Smax method requires no user-input parameters, and it consistently provides rates of success that approximately oscillate between the 72% and the 81%.

The presented clustering approach noticeably improves the rate of correct clustering cases for the specific scenario of route clustering.

Background

Methods

Results

Conclusions

Clinical relevance

Consumption of food and water is tightly regulated by the nervous system to maintain internal nutrient homeostasis. Although generally considered independently, interactions between hunger and thirst drives are important to coordinate competing needs. In chapter 1, I provide a review of hunger regulation and thirst regulation in mammals and Drosophila melanogaster. I then discuss the neural and hormonal coordination of hunger and thirst in both mammals and D. melanogaster.

In Drosophila, four neurons called the Interoceptive Subesophageal zone Neurons (ISNs) respond to intrinsic hunger and thirst signals to oppositely regulate sucrose and water ingestion. In chapter 2, I characterize the neural circuit downstream of the ISNs. This work is presented in the form of a preprint first author manuscript. Using the fly brain connectome, genetic tools, behavioral assays, and functional imaging, I show, together with co-authors Gina Pontes, Nicholas Jourjine and Alexander Del Toro, that the ISNs modulate a peptidergic network of neurons. These include a novel cell type Bilateral T shaped neuron (BiT), insulin producing cells (IPC), crustacean cardioactive peptide (CCAP) neurons, and CCHamide-2 receptor isoform RA (CCHa2R-RA) neurons. These neurons contribute differentially to ingestion of sugar and water, with BiT, IPCs and CCAP neurons oppositely regulating sugar and water ingestion, and CCHa2R-RA neurons modulating only water ingestion. Thus, the decision to consume sugar or water occurs via regulation of a broad peptidergic network that integrates internal signals of nutritional state to generate nutrient-specific ingestion.

In chapter 3, I characterize other neurons that are involved in sugar and/or water ingestion. Using a computational approach to identify neurons in close proximity, genetic manipulation, behavioral assays, and in vivo functional imaging, I characterized several neurons involved in sugar and/or water ingestion regulation. Aster, bidirectionally regulates sugar and water ingestion just as the ISNs, Horseshoe, decreases both sugar and water ingestion, and Cowboy likely promotes sugar ingestion. In vivo functional connectivity experiments revealed that they were not downstream of the ISNs, however, Aster, possibly Horseshoe, and another cell type Gallinule are downstream of sensory neurons. Thus, I have identified another cell type that bidirectionally regulates sugar and water ingestion, two cell types that modulate feeding, and a cell type that likely conveys gustatory information to memory centers in the fly brain.

In chapter 4, I describe with co-authors Zoila Alvarez-Aponte, Rachel Brem, Diana Bautista and Denzil Streete, the development and implementation of the Inclusive Excellence in Quals Prep (IEQP) program. This program was designed to provide mentorship, community, and academic support for students from diverse backgrounds as they prepared for their QE. The main components for IEQP program included pairing students with graduate student mentors, academic and wellness workshops, and community building events. This program was first implemented on a pilot cohort of 11 graduate students. After program evaluation, the most significant component of the program was peer mentorship. After program completion, students’ perception of their preparedness, QE-related skills, the support received from their advisors, and the agency they felt over their proposed work increased.

In the final part of this dissertation, chapter 5, I summarize the main findings of this dissertation and propose future directions for exploration.

Pathogen surveillance must be part of any population supplementation or reintroduction program for the conservation of threatened and endangered species. The unintended transmission of pathogens can have devastating effects on these already at-risk populations or the natural ecosystem at large. In the San Francisco Estuary (estuary), abundance of the endemic Delta Smelt (Hypomesus transpacificus) has declined to the point where regulatory managers are preparing to augment the wild population using fish propagated in a hatchery to prevent species extinction. Although disease is not an overt cause of population decline, comprehensive pathogen presence and prevalence data are lacking. Here, we performed a pilot study that applied molecular assays originally developed in salmonids to assess the presence of a wide variety of pathogens in the gill tissue of cultured and wild Delta Smelt—as well as cultured fish—deployed in enclosures in the estuary. We found the assays to be highly sensitive, and observed positive detections of a single pathogen, Ichthyophthirius multifiliis, in 13% of cultured Delta Smelt. We also detected ten other pathogens at very low levels in cultured, enclosure-deployed, and wild Delta Smelt that likely represent the ambient pathogen composition in the estuary (as opposed to actual infection). Our results corroborate previous work that cultured Delta Smelt do not appear to present a high risk for pathogen transmission during population supplementation or reintroduction. However, the molecular pathogen screening assays tested here have great utility as an early warning system indicator of when further diagnostic testing might be necessary to limit the extent and frequency of disease outbreaks; their utility will be further increased once they are customized for Delta Smelt.