An unusual foreign body of esophagus

We report a rare case of an unusually long foreign body (Datun) impacted in the esophagus of a 56 year-old gentleman. He was literate, without any psychiatric illness and had been using “Neem” (Azadirachta indica) stick for cleaning his teeth for the past twenty years. Neem sticks are used for brushing teeth, perhaps one of the earliest and very effective dental care. On closer questioning he revealed his habit of passing the Neem stick into his throat with the aim of cleaning it too while cleaning his teeth. He presented to our emergency early in the morning with this strange long foreign body impacted in his esophagus which was removed successfully using a Jackson’s adult rigid oesophagoscope. We believe this to be the first case of such an unusually long foreign body to be reported in the literature

New Approximability Results for the Robust k-Median Problem

We consider a robust variant of the classical $k$-median problem, introduced by Anthony et al. \cite{AnthonyGGN10}. In the \emph{Robust $k$-Median problem}, we are given an $n$-vertex metric space $(V,d)$ and $m$ client sets $\set{S_i \subseteq V}_{i=1}^m$. The objective is to open a set $F \subseteq V$ of $k$ facilities such that the worst case connection cost over all client sets is minimized; in other words, minimize $\max_{i} \sum_{v \in S_i} d(F,v)$. Anthony et al.\ showed an $O(\log m)$ approximation algorithm for any metric and APX-hardness even in the case of uniform metric. In this paper, we show that their algorithm is nearly tight by providing $\Omega(\log m/ \log \log m)$ approximation hardness, unless ${\sf NP} \subseteq \bigcap_{\delta >0} {\sf DTIME}(2^{n^{\delta}})$. This hardness result holds even for uniform and line metrics. To our knowledge, this is one of the rare cases in which a problem on a line metric is hard to approximate to within logarithmic factor. We complement the hardness result by an experimental evaluation of different heuristics that shows that very simple heuristics achieve good approximations for realistic classes of instances.Comment: 19 page

On the NP-Hardness of Approximating Ordering Constraint Satisfaction Problems

We show improved NP-hardness of approximating Ordering Constraint Satisfaction Problems (OCSPs). For the two most well-studied OCSPs, Maximum Acyclic Subgraph and Maximum Betweenness, we prove inapproximability of $14/15+\epsilon$ and $1/2+\epsilon$. An OCSP is said to be approximation resistant if it is hard to approximate better than taking a uniformly random ordering. We prove that the Maximum Non-Betweenness Problem is approximation resistant and that there are width-$m$ approximation-resistant OCSPs accepting only a fraction $1 / (m/2)!$ of assignments. These results provide the first examples of approximation-resistant OCSPs subject only to P $\neq$ \NP

Understanding Eating Behaviors of New Dehli\u27s Youth

This qualitative study documents perceived benefits of and barriers to engaging in healthy eating behaviors among adolescents in New Delhi, India. Researchers explored factors that influenced the consumption of breakfast, fruits and vegetables, and soft drinks in this population and adolescents’ ideas about how to intervene to encourage or discourage, respectively, these behaviors. Students (n=151 6th and 8th graders) from five private schools participated in focus group discussions. Findings showed that the majority of youth eat breakfast that may consist of traditional and Western choices. Despite sound knowledge of the benefits of fruits and vegetables consumption, adolescents do not eat the recommended daily servings due to flavor preferences. Soft drink consumption was, reportedly, universal. Several factors influenced these decisions and details are herein provided. The paucity of studies on this subject provides researchers with the opportunity to explore how eating patterns of Indian youth might be shaping the health and disease landscape of India in the upcoming decades. The study adds to the slim body of literature on the subject and could be used to inform future nutrition interventions in India

Lately Exposed Amorphous Water Ice on Comet 49P/Arend-Rigaux

Comet 49P/ Arend-Rigaux, thought to be a low activity comet since the 1980's was found to be active in its recent apparitions. Recent analysis of the data obtained from Spitzer observation of the comet in 2006 compared with laboratory spectra has revealed amorphous water ice on the surface. In addition, in 2012 a jet was found to appear during its subsequent perihelion passage as witnessed during an observation carried out on 26th March 2012 using the PRL telescope at Mt. Abu. This confirms recent activity of Comet 49P/Arend-Rigaux due to the volatile subsurface materials exposed after several passages close to the Sun. Our result confirms the subsurface ices on cometary nuclei and insists for more observations for a better understanding

The pressure-amorphized state in zirconium tungstate: a precursor to decomposition

In contrast to widely accepted view that pressure-induced amorphization arises due to kinetic hindrance of equilibrium phase transitions, here we provide evidence that the metastable pressure-amorphized state in zirconium tungstate is a precursor to decomposition of the compound into a mixture of simple oxides. This is from the volume collapse ΔV across amorphization, which is obtained for the first time by measuring linear dimensions of irreversibly amorphized samples during their recovery to the original cubic phase upon isochronal annealing up to 1000 K. The anomalously large ΔV of 25.7 ± 1.2% being the same as that expected for the decomposition indicates that this amorphous state is probably a precursor to kinetically hindered decomposition. A P–T diagram of the compound is also proposed

Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink

Terrestrial ecosystem models commonly represent vegetation in terms of plant functional types (PFTs) and use their vegetation attributes in calculations of the energy and water balance as well as to investigate the terrestrial carbon cycle. Sub-grid scale variability of PFTs in these models is represented using different approaches with the "composite" and "mosaic" approaches being the two end-members. The impact of these two approaches on the global carbon balance has been investigated with the Canadian Terrestrial Ecosystem Model (CTEM v 1.2) coupled to the Canadian Land Surface Scheme (CLASS v 3.6). In the composite (single-tile) approach, the vegetation attributes of different PFTs present in a grid cell are aggregated and used in calculations to determine the resulting physical environmental conditions (soil moisture, soil temperature, etc.) that are common to all PFTs. In the mosaic (multi-tile) approach, energy and water balance calculations are performed separately for each PFT tile and each tile's physical land surface environmental conditions evolve independently. Pre-industrial equilibrium CLASS-CTEM simulations yield global totals of vegetation biomass, net primary productivity, and soil carbon that compare reasonably well with observation-based estimates and differ by less than 5% between the mosaic and composite configurations. However, on a regional scale the two approaches can differ by > 30%, especially in areas with high heterogeneity in land cover. Simulations over the historical period (1959–2005) show different responses to evolving climate and carbon dioxide concentrations from the two approaches. The cumulative global terrestrial carbon sink estimated over the 1959–2005 period (excluding land use change (LUC) effects) differs by around 5% between the two approaches (96.3 and 101.3 Pg, for the mosaic and composite approaches, respectively) and compares well with the observation-based estimate of 82.2 ± 35 Pg C over the same period. Inclusion of LUC causes the estimates of the terrestrial C sink to differ by 15.2 Pg C (16%) with values of 95.1 and 79.9 Pg C for the mosaic and composite approaches, respectively. Spatial differences in simulated vegetation and soil carbon and the manner in which terrestrial carbon balance evolves in response to LUC, in the two approaches, yields a substantially different estimate of the global land carbon sink. These results demonstrate that the spatial representation of vegetation has an important impact on the model response to changing climate, atmospheric CO₂ concentrations, and land cover

A Hypergraph Dictatorship Test with Perfect Completeness

A hypergraph dictatorship test is first introduced by Samorodnitsky and Trevisan and serves as a key component in their unique games based \PCP construction. Such a test has oracle access to a collection of functions and determines whether all the functions are the same dictatorship, or all their low degree influences are $o(1).$ Their test makes $q\geq3$ queries and has amortized query complexity $1+O(\frac{\log q}{q})$ but has an inherent loss of perfect completeness. In this paper we give an adaptive hypergraph dictatorship test that achieves both perfect completeness and amortized query complexity $1+O(\frac{\log q}{q})$.Comment: Some minor correction