Small Extended Formulation for Knapsack Cover Inequalities from Monotone Circuits

Initially developed for the min-knapsack problem, the knapsack cover inequalities are used in the current best relaxations for numerous combinatorial optimization problems of covering type. In spite of their widespread use, these inequalities yield linear programming (LP) relaxations of exponential size, over which it is not known how to optimize exactly in polynomial time. In this paper we address this issue and obtain LP relaxations of quasi-polynomial size that are at least as strong as that given by the knapsack cover inequalities. For the min-knapsack cover problem, our main result can be stated formally as follows: for any $\varepsilon >0$, there is a $(1/\varepsilon)^{O(1)}n^{O(\log n)}$-size LP relaxation with an integrality gap of at most $2+\varepsilon$, where $n$ is the number of items. Prior to this work, there was no known relaxation of subexponential size with a constant upper bound on the integrality gap. Our construction is inspired by a connection between extended formulations and monotone circuit complexity via Karchmer-Wigderson games. In particular, our LP is based on $O(\log^2 n)$-depth monotone circuits with fan-in~$2$ for evaluating weighted threshold functions with $n$ inputs, as constructed by Beimel and Weinreb. We believe that a further understanding of this connection may lead to more positive results complementing the numerous lower bounds recently proved for extended formulations.Comment: 21 page

Geographic and Host-Microbe Symbiotic Influence on Secondary Metabolism

This thesis is composed of studies that regard the advancement to the Arctic region and the importance of host-microbe interactions in natural product discovery. Bioactive metabolites have been reported from a myriad of marine and terrestrial organisms around the world including plants, insects, sponges, tunicates, bacteria, and fungi among others. Many macroorganisms, of which the metabolites are found, depend on the symbiotic relationship of microorganisms for metabolite production. The scope of this work is to investigate secondary metabolism of both marine and terrestrial organisms from different areas of the world as well as search for the importance of host-microbe symbiosis on a chemical level. Chapter 1 comprises a review of bioactive sponge secondary metabolites reported from Arctic sponge species. Although more tropical and easily accessible waters have been investigated, other regions including the more dark, cold polar regions, specifically the Arctic, represent a less explored frontier for secondary metabolite discovery. Additionally, a survey of a 2010 sponge collection in the Aleutian Islands, AK, is displayed and assesses the chemical potential of sponge species in the area. The description of two small molecule aldehydes with reported broad spectrum bioactivity from a new species of Guitarra obtained through this collection is also given. Chapter 2 discusses the chemical investigation of a new sponge species of the genus Monanchora from the Aleutian Islands. Different species of Monanchora, including M. pulchra, have been classified within the region. Through de-replication, members of the class of potent cytotoxic, antimicrobial compounds known as the monanchocidins were identified from the sponge. Further investigation of the metabolome and development of bioactivity will continue to be investigated in the future. Studies have suggested that the chemical complexity of sponges is dependent upon not only the sponge itself, but rather an intricate associated microbial community. Chapter 3 presents the results of fermentations of sponge-associated Micromonospora sp. M42, yielding seven small molecule secondary metabolites, with four belonging to a class of broad spectrum bioactive molecules known as diketopiperazines. Previous research suggests that these compounds possess bioactivities that can benefit the sponge in a symbiotic relationship, including growth promoter and antifouling properties. Screening of the crude extracts revealed the presence of the diketopiperazines in the sponge. Additionally, a genomic evaluation of the biosynthetic machinery of M42 was performed. This data was generated in supplement of previously done work regarding the entire sponge-associated microbiome and previous confirmation of manzamine production by M42 as well as a series of biotranformation studies that add insight to the generation of the array of manzamine derivatives found in the sponge. Chapter 4 discusses the metabolite nicotianamine, a compound found in all higher plant species that possesses antioxidant and metal-binding properties that can be helpful in use as a food preservative in replacement of EDTA. Preliminary data into the optimization of the isolation and quantification of nicotianamine on an analytical scale is presented

Breathing as a Fundamental Rhythm of Brain Function

Ongoing fluctuations of neuronal activity have long been considered intrinsic noise that introduces unavoidable and unwanted variability into neuronal processing, which the brain eliminates by averaging across population activity (Georgopoulos et al., 1986; Lee et al., 1988; Shadlen and Newsome, 1994; Maynard et al., 1999). It is now understood, that the seemingly random fluctuations of cortical activity form highly structured patterns, including oscillations at various frequencies, that modulate evoked neuronal responses (Arieli et al., 1996; Poulet and Petersen, 2008; He, 2013) and affect sensory perception (Linkenkaer-Hansen et al., 2004; Boly et al., 2007; Sadaghiani et al., 2009; Vinnik et al., 2012; Palva et al., 2013). Ongoing cortical activity is driven by proprioceptive and interoceptive inputs. In addition, it is partially intrinsically generated in which case it may be related to mental processes (Fox and Raichle, 2007; Deco et al., 2011). Here we argue that respiration, via multiple sensory pathways, contributes a rhythmic component to the ongoing cortical activity. We suggest that this rhythmic activity modulates the temporal organization of cortical neurodynamics, thereby linking higher cortical functions to the process of breathing

Vaginal misoprostol before elective cesarean section for preventing neonatal respiratory distress: a randomized controlled trial

Objective: The current study aims to evaluate the efficacy of vaginal misoprostol before elective cesarean section (ECS) for preventing the occurrence of neonatal respiratory distress (RD). Materials and Methods: A randomized controlled trial (NCT03239327) was carried out in a tertiary-care university-affiliated hospital between June 2016 and August 2017. All eligible pregnant women scheduled for ECS were randomly allocated in a 1:1 ratio to two groups. One group, the Misoprostol group, received a misoprostol 50 mcg vaginal tablet 60 minutes before ECS while the other, the Control group, received no drugs before ECS. The primary outcome was the rate of neonatal RD among the study groups. Results: The study included 146 women in each arm, with no significant difference between the baseline characteristics of members in each group. Primary outcomes resulted in 22 (15.1%) newborns in the misoprostol group having RD at birth versus 44 (30.1%) newborns with RD in the control (P =0.02). No differences were found between the groups regarding the need for neonatal intensive care unit (NICU) admission (P =0.61), duration of NICU stay (P =0.08) and neonatal mortality rate (P =0.73). Conclusion: Prophylactic vaginal misoprostol at a dose of 50 mcg administered 60 minutes before ECS could reduce the rate of neonatal RD and improve the neonatal respiratory outcomes

AI in Software Engineering: A Survey on Project Management Applications

Artificial Intelligence (AI) refers to the intelligence demonstrated by machines, and within the realm of AI, Machine Learning (ML) stands as a notable subset. ML employs algorithms that undergo training on data sets, enabling them to carry out specific tasks autonomously. Notably, AI holds immense potential in the field of software engineering, particularly in project management and planning. In this literature survey, we explore the use of AI in Software Engineering and summarize previous works in this area. We first review eleven different publications related to this subject, then compare the surveyed works. We then comment on the possible challenges present in the utilization of AI in software engineering and suggest possible further research avenues and the ways in which AI could evolve with software engineering in the future

Gene Expression Profiling of Bronchoalveolar Lavage Cells Preceding a Clinical Diagnosis of Chronic Lung Allograft Dysfunction.

BackgroundChronic Lung Allograft Dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Although CLAD is usually not responsive to treatment, earlier identification may improve treatment prospects.MethodsIn a nested case control study, 1-year post transplant surveillance bronchoalveolar lavage (BAL) fluid samples were obtained from incipient CLAD (n = 9) and CLAD free (n = 8) lung transplant recipients. Incipient CLAD cases were diagnosed with CLAD within 2 years, while controls were free from CLAD for at least 4 years following bronchoscopy. Transcription profiles in the BAL cell pellets were assayed with the HG-U133 Plus 2.0 microarray (Affymetrix). Differential gene expression analysis, based on an absolute fold change (incipient CLAD vs no CLAD) >2.0 and an unadjusted p-value ≤0.05, generated a candidate list containing 55 differentially expressed probe sets (51 up-regulated, 4 down-regulated).ResultsThe cell pellets in incipient CLAD cases were skewed toward immune response pathways, dominated by genes related to recruitment, retention, activation and proliferation of cytotoxic lymphocytes (CD8+ T-cells and natural killer cells). Both hierarchical clustering and a supervised machine learning tool were able to correctly categorize most samples (82.3% and 94.1% respectively) into incipient CLAD and CLAD-free categories.ConclusionsThese findings suggest that a pathobiology, similar to AR, precedes a clinical diagnosis of CLAD. A larger prospective investigation of the BAL cell pellet transcriptome as a biomarker for CLAD risk stratification is warranted

Acute encephalitis syndrome surveillance, Kushinagar district, Uttar Pradesh, India, 2011-2012

In India, quality surveillance for acute encephalitis syndrome (AES), including laboratory testing, is necessary for understanding the epidemiology and etiology of AES, planning interventions, and developing policy. We reviewed AES surveillance data for January 2011-June 2012 from Kushinagar District, Uttar Pradesh, India. Data were cleaned, incidence was determined, and demographic characteristics of cases and data quality were analyzed. A total of 812 AES case records were identified, of which 23\% had illogical entries. AES incidence was highest among boys<6 years of age, and cases peaked during monsoon season. Records for laboratory results (available for Japanese encephalitis but not AES) and vaccination history were largely incomplete, so inferences about the epidemiology and etiology of AES could not be made. The low-quality AES/Japanese encephalitis surveillance data in this area provide little evidence to support development of prevention and control measures, estimate the effect of interventions, and avoid the waste of public health resources