Output Feedback Invariants

The paper is concerned with the problem of determining a complete set of invariants for output feedback. Using tools from geometric invariant theory it is shown that there exists a quasi-projective variety whose points parameterize the output feedback orbits in a unique way. If the McMillan degree $n\geq mp$, the product of number of inputs and number of outputs, then it is shown that in the closure of every feedback orbit there is exactly one nondegenerate system.Comment: 15 page

Degree of the generalized Pl\"ucker embedding of a Quot scheme and Quantum cohomology

We compute the degree of the generalized Pl\"ucker embedding $\kappa$ of a Quot scheme $X$ over \PP^1. The space $X$ can also be considered as a compactification of the space of algebraic maps of a fixed degree from \PP^1 to the Grassmanian $\rm{Grass}(m,n)$. Then the degree of the embedded variety $\kappa (X)$ can be interpreted as an intersection product of pullbacks of cohomology classes from $\rm{Grass}(m,n)$ through the map $\psi$ that evaluates a map from \PP^1 at a point x\in \PP^1. We show that our formula for the degree verifies the formula for these intersection products predicted by physicists through Quantum cohomology~\cite{va92}~\cite{in91}~\cite{wi94}. We arrive at the degree by proving a version of the classical Pieri's formula on the variety $X$, using a cell decomposition of a space that lies in between $X$ and $\kappa (X)$.Comment: 18 pages, Latex documen

International poverty projections

The authors investigate the methodology used in projections of international poverty - particularly those used in many World Bank documents. The methodology, as developed by Ahluwalia, Carter, and Chenery (1979) in an influential paper, is examined critically and subjected to sensitivity analysis. It was found that their projections of poverty are not robust to reasonable changes and improvements in the methodology; in some cases, even the projections'time trend is reversed. Thus, analysts and policymakers should treat such global forecasts of poverty with caution.Economic Theory&Research,Achieving Shared Growth,Economic Conditions and Volatility,Inequality,Environmental Economics&Policies

Identifying Unclear Questions in Community Question Answering Websites

Thousands of complex natural language questions are submitted to community question answering websites on a daily basis, rendering them as one of the most important information sources these days. However, oftentimes submitted questions are unclear and cannot be answered without further clarification questions by expert community members. This study is the first to investigate the complex task of classifying a question as clear or unclear, i.e., if it requires further clarification. We construct a novel dataset and propose a classification approach that is based on the notion of similar questions. This approach is compared to state-of-the-art text classification baselines. Our main finding is that the similar questions approach is a viable alternative that can be used as a stepping stone towards the development of supportive user interfaces for question formulation.Comment: Proceedings of the 41th European Conference on Information Retrieval (ECIR '19), 201

Unlocking the Secrets of Stem Cells in Orthodontics

Human Periodontal Ligament Stem Cells (hPDLSCs) have immense potential for use in tissue regeneration and angiogenesis. These cells are influenced by mechanical forces, particularly in orthodontic applications. Understanding how mechanical stress modulates stem cell behavior is essential for optimizing therapeutic strategies

Clinical submission of supernumerary head of adducter brevis muscle

Adductor brevis is an important member of the adductor family occupying the medial compartment of the thigh executing the function of adduction and medial rotation. Deviations from normal anatomy are unusual and rarely reported. A survey of anatomical archives revealed occasional mention of additional bellies of adductor brevis muscle. The present study reports a double belly of adductor brevis muscle (AB) found during a cadaveric dissection class for medical students. The left sided AB displayed two bellies disposed in the same plane. This case report attempts to present the clinical applications of supernumerary bellies of this important adductor muscle of the thigh. It is feasible to categorize these muscular variations upon specialized radiological procedures such as CT and MRI scans only if the radiologist possesses satisfactory understanding of variant anatomy of this region. It is thereafter inferred that upon recognition these muscles present a fair chance of being of utilitised in reconstructions. A biomechanical overview of the present anomaly is also attempte

Short term analysis of the functional outcome in complex primary hip arthroplasty

Background: Total hip arthroplasty is the most commonly performed reconstructive procedure that replaces the femoral head, neck and acetabular articular surface. THA is a highly successful procedure that has made numerous patients return to excellent function without pain and provides a stable, pain-free mobile joint. The purpose of this study is short term analysis (retrospective and prospective study) of the functional outcome in 30 patients who underwent complex primary hip arthroplasty.Methods: A retrospective and prospective study was done to evaluate the functional outcome in 30 patients who underwent complex primary total hip replacement and to analyze the results. A detailed clinical examination and radiological assessment was done to assess the nature of deformity, bone stock, functional impairment and component sizes. Pre-operative templating is routinely done in all cases. Pre-operative clinical evaluation was done using modified Harris hip scoring.Results: Most of the patient was operated by Hardinge lateral approach (22 Patients). 8 patients were operated by Posterior Southern-Moore approach. In our study the average surgical time delay was 6 days ranging from 5 to 17 days. The average surgical time was 120 minutes ranging from 60 minutes to 3 hours.Conclusions: The surgical technique employed is unique to each complex case. Surgeon expertise is also a must to deal with complex hips. Complex primary THA is an emerging trend with better clinical and functional outcome with the presently available modular implants and improved surgical techniques.