Corporate Yield Spreads: Default Risk or Liquidity? New Evidence from the Credit-Default Swap Market

We use the information in credit-default swaps to obtain direct measures of the size of the default and nondefault components in corporate spreads. We find that the majority of the corporate spread is due to default risk. This result holds for all rating categories and is robust to the definition of the riskless curve. We also find that the nondefault component is time varying and strongly related to measures of bond-specific illiquidity as well as to macroeconomic measures of bond-market liquidity.

Lithotectonic Landslides and Hazards in Parts of Garhwal-Kumaon Himalayas

Landslides produce an awesome picture of the hill sides with steep scarred, hollowed and gullied geomorphic features devoid of vegetation particularly between the major thrust zones. A look on the tectono-stratigraphic map of the region with marked major tectonic features like the Main Central Thrust (MCT), North Almora Thrust (NAT) and South Almora Thrust (SAT) indicates that the region is highly prone to landslides and is affected by repeated tectonic and orogenic processes. These factors with the nature of the rocks, climate and the heavy monsoon rains are responsible for sculpturing the region. The mountain features and the valley slopes thus indicate the influence of the activities and the dynamic forces at a particular locality and time. Many times developmental activities have also contributed towards the degradation of the environs due to disturbance of the already stabilized slopes and the angles of repose e.g. along the Rishikesh-Badrinath Road, where a new alignment has been given, sometimes overlapping the old pilgrim route

Acquisition, representation and rule generation for procedural knowledge

Current research into the design and continuing development of a system for the acquisition of procedural knowledge, its representation in useful forms, and proposed methods for automated C Language Integrated Production System (CLIPS) rule generation is discussed. The Task Analysis and Rule Generation Tool (TARGET) is intended to permit experts, individually or collectively, to visually describe and refine procedural tasks. The system is designed to represent the acquired knowledge in the form of graphical objects with the capacity for generating production rules in CLIPS. The generated rules can then be integrated into applications such as NASA's Intelligent Computer Aided Training (ICAT) architecture. Also described are proposed methods for use in translating the graphical and intermediate knowledge representations into CLIPS rules

A general technique for deterministic model-cycle-level debugging

Efficient use of FPGA resources requires FPGA-based performance models of complex hardware to implement one model cycle, i.e., one time-step of the original synchronous system, in several implementation cycles. Generally implementation cycles have no simple relationship with model cycles, and it is tricky to reconstruct the state of the synchronous system at the model-cycle boundaries if only implementation-cycle-level control and information is provided. A good debugging facility needs to provide: complete control over the functioning of the target design being simulated; fast and easy access to all the significant target design state for both monitoring and modification; and some means of accomplishing deterministic execution when the target design is a multicore processor running a parallel application. Moreover, these features need to be provided in a manner which does not incur substantial resource and performance penalties. In this paper, we present a debugging technique based on the LI-BDN theory. We show how the technique facilitates deterministic model-cycle-level debugging. We used it to build the debugging infrastructure for Arete, which is an FPGA-based cycle-accurate multicore simulator. The resource and performance penalties of our debugging technique are minimal; in Arete the debugging infrastructure has area and performance overheads of 5% and 6%, respectively.IBM Researc

GCMS analysis & assessment of antimicrobial potential of rhizospheric Actinomycetes of AIA3 isolate

111-119Plants have been used for medicine to support human health in many regions in the world by researchers since ancient times. Plants and soil organisms have been found to have very high therapeutic potential as they produce many natural products. Evolving drug resistance towards nearly all anti-infection drugs, lead to the fast development of new drugs. Many natural products or secondary metabolites have been used for animal and human health. Recently, many new secondary metabolites from actinomycetes have been isolated and reported as important compounds with different activities like anti-microbial, anti-oxidant, anti-inflammatory, anti-androgenic and anticancer agents, etc. In this study isolation of actinomycetes was carried out on actinomycetes isolation agar media (AIA). Characterization and biochemical tests were performed and followed by fermentation and solvent extraction by four solvents for example- Benzene, pet ether, ethyl acetate, chloroform. GCMS was performed for identification of compounds present in culture broth. Major compounds present were Octanal,Pyrrolo[1,2-a]pyrazine-1,4-dione,hexahydro-3-(2-methylpropyl), Dibutyl phthalate, N-hexadecanoic acid, 1-nonadecene, Heptadecane, Octadecanoic acid, 3,7,11,15-tetramethyl-2-hexadecene, Dihydroergotamine, Hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester, Octadecanoic acid, 2,3-dihydroxypropyl ester, 13-docosenamide, and 4-tert-butylcalix[4]arene. Crude obtained was checked for their antimicrobial activity and inhibition zones (IZ) were noted on Mullar Hinton agar (MHA) media against indicator organisms like Staphylococcus aureus (MTCC-3160) (IZ=Ben-18 mm, E.A-25 mm), Pseudomonas aeruginosa (MTCC 1688) (IZ=Ben-11 mm, Chl-14 mm, E.A-24 mm), Klebsiella pneumonia (MTCC-432) (IZ=Ben-19 mm, Chl-20 mm, E.A-34 mm), Proteus vulgaris (MTCC-7306) (IZ=Benzene-10 mm, E.A-30 mm), Bacillus subtilis (MTCC-441). Identification of compounds was carried out by NIST 14 library

TE2Rules: Extracting Rule Lists from Tree Ensembles

Tree Ensemble (TE) models (e.g. Gradient Boosted Trees and Random Forests) often provide higher prediction performance compared to single decision trees. However, TE models generally lack transparency and interpretability, as humans have difficulty understanding their decision logic. This paper presents a novel approach to convert a TE trained for a binary classification task, to a rule list (RL) that is a global equivalent to the TE and is comprehensible for a human. This RL captures all necessary and sufficient conditions for decision making by the TE. Experiments on benchmark datasets demonstrate that, compared to state-of-the-art methods, (i) predictions from the RL generated by TE2Rules have high fidelity with respect to the original TE, (ii) the RL from TE2Rules has high interpretability measured by the number and the length of the decision rules, (iii) the run-time of TE2Rules algorithm can be reduced significantly at the cost of a slightly lower fidelity, and (iv) the RL is a fast alternative to the state-of-the-art rule-based instance-level outcome explanation techniques

Induced pluripotent stem cell based modeling of gastrointestinal disease using human intestinal organoids

The human gastrointestinal (GI) epithelium performs major physiologic functions that are critical to survival, health, and homeostatic equilibrium. While model organisms and in vitro cell culture systems have been widely used to study both normal and disease states of the GI tract, these often fail to fully recapitulate critical features of in vivo intestinal tissue. In recent years, investigators have harnessed the ability to perform directed differentiation of human induced pluripotent stem cells (iPSCs) towards cell types originating from all three embryonic germ layers, most notably a wide variety of endodermal lineages, in an attempt to generate in vitro models that better recapitulate human physiology and key developmental milestones. These iPSC-derived cells contain the exact genetic background of a particular donor or patient and are easily amenable to gene-editing, making them particularly advantageous in comparison to non-human model organisms or in vitro cell culture systems often derived from malignant tissue. Here, we report the efficient generation of iPSC-derived mesenchyme-free human intestinal organoids (HIOs) that can be primed towards colonic or proximal intestinal lineages in serum-free defined conditions. By generating a novel CDX2-eGFP iPSC knock-in reporter line to track the emergence of hindgut progenitors, we follow the kinetics of CDX2 expression throughout directed differentiation, enabling the purification of intestinal progenitors. We employ these mesenchyme free HIOs to highlight cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction using cystic fibrosis (CF) patient-derived iPSC lines before and after correction of the CFTR mutation. We also demonstrate that these HIOs represent a powerful tool to model pathogen-mediated GI illness, characterizing the intestinal epithelial host response to infection by the coronavirus SARS-CoV-2 as well as two filoviruses, Ebola (EBOV) and Marburg (MARV). Finally, we report the generation of a clinically relevant library of iPSCs derived from patients with Crohn’s Disease (CD), including successful directed differentiation of these lines to a relevant immune cell type, as a proof of concept for their use in CD in vitro modeling. Taken together, our results provide a comprehensive and reductive iPSC-based model to study disease states of the intestinal epithelium, ranging from enteric viral infection to mendelian disorders such as CF and autoimmune conditions such as inflammatory bowel disease (IBD), highlighting the potential of organoids as a powerful tool for disease modeling and therapeutics development