125 research outputs found
Dihedral Sieving Phenomena
Cyclic sieving is a well-known phenomenon where certain interesting
polynomials, especially -analogues, have useful interpretations related to
actions and representations of the cyclic group. We propose a definition of
sieving for an arbitrary group and study it for the dihedral group
of order . This requires understanding the generators of the representation
ring of the dihedral group. For odd, we exhibit several instances of
dihedral sieving which involve the generalized Fibonomial coefficients,
recently studied by Amdeberhan, Chen, Moll, and Sagan. We also exhibit an
instance of dihedral sieving involving Garsia and Haiman's -Catalan
numbers.Comment: 10 page
Analysis of sum-of-squares relaxations for the quantum rotor model
The noncommutative sum-of-squares (ncSoS) hierarchy was introduced by
Navascu\'{e}s-Pironio-Ac\'{i}n as a sequence of semidefinite programming
relaxations for approximating values of noncommutative polynomial optimization
problems, which were originally intended to generalize quantum values of
nonlocal games. Recent work has started to analyze the hierarchy for
approximating ground energies of local Hamiltonians, initially through rounding
algorithms which output product states for degree-2 ncSoS applied to Quantum
Max-Cut. Some rounding methods are known which output entangled states, but
they use degree-4 ncSoS. Based on this, Hwang-Neeman-Parekh-Thompson-Wright
conjectured that degree-2 ncSoS cannot beat product state approximations for
Quantum Max-Cut and gave a partial proof relying on a conjectural
generalization of Borrell's inequality. In this work we consider a family of
Hamiltonians (called the quantum rotor model in condensed matter literature or
lattice vector model in quantum field theory) with infinite-dimensional
local Hilbert space , and show that a degree-2 ncSoS
relaxation approximates the ground state energy better than any product state.Comment: 28 pages, submitted to QIP 202
Generalized inverse of a matrix and its applications
This article does not have an abstract
Chow Rings of Vector Space Matroids
The Chow ring of a matroid (or more generally, atomic latice) is an invariant
whose importance was demonstrated by Adiprasito, Huh and Katz, who used it to
resolve the long-standing Heron-Rota-Welsh conjecture. Here, we make a detailed
study of the Chow rings of uniform matroids and of matroids of finite vector
spaces. In particular, we express the Hilbert series of such matroids in terms
of permutation statistics; in the full rank case, our formula yields the
maj-exc -Eulerian polynomials of Shareshian and Wachs. We also provide a
formula for the Charney-Davis quantities of such matroids, which can be
expressed in terms of either determinants or -secant numbers
Conditions for optimality and validity of simple least squares theory
This article does not have an abstract
Quantitative and qualitative assessment of exploitation of juvenile cephalopods from the Arabian Sea and Bay of Bengal and determination of minimum legal sizes
Using the minimum size at maturity (MSM) as a biological reference point and relatively low
reproductive loads and generation times of the studied animals, the minimum legal sizes (MLS) for
the Indian squid Loligo duvauceli, the pharaoh cuttlefish Sepia pharaonis and for the webfoot octopus
Octopus membranaceous was fixed at 80, 115 and 45 mm Dorsal Mantle Length (DML) respectively
with corresponding minimum legal weights at 25, 150 and 15 g. For L. duvauceli, during 1997-2001,
12.8% of the average catch was constituted by juveniles, the proportion being higher along the west
coast. In 2002-05, the proportion of juveniles was lower at 5.3% and the total weights were also much
less (1817 t as compared to 5354 t). In the case of S. pharaonis, 6.9% (2281 t) of the catch was
constituted by juveniles, but the proportion was very high (22.4%) along the east coast. In O.
membranaceous during 2002-04, an estimated 527 t (5.9%) of the total catch comprised of juveniles.
The present Lmean in the fishery is lower than the Lopt and their difference is considerably high at 60
mm for L. duvauceli. However, in the case of S. pharaonis this difference is only 10 mm and in the
case of O. membranaceous the Lmean is higher than the Lopt. If the juveniles are permitted to grow
to Lmean by implementing the MLS, the estimated economic gain is to the tune of Rs. 426 crores per
annum. The present study shows that harvest weights can be improved by up to 34 times and would
result in higher incomes to trawl fishers
Production of galactitol from galactose by the oleaginous yeast Rhodosporidium toruloides IFO0880
Background
Sugar alcohols are commonly used as low-calorie sweeteners and can serve as potential building blocks for bio-based chemicals. Previous work has shown that the oleaginous yeast Rhodosporidium toruloides IFO0880 can natively produce arabitol from xylose at relatively high titers, suggesting that it may be a useful host for sugar alcohol production. In this work, we explored whether R. toruloides can produce additional sugar alcohols.
Results
Rhodosporidium toruloides is able to produce galactitol from galactose. During growth in nitrogen-rich medium, R. toruloides produced 3.2 ± 0.6 g/L, and 8.4 ± 0.8 g/L galactitol from 20 to 40 g/L galactose, respectively. In addition, R. toruloides was able to produce galactitol from galactose at reduced titers during growth in nitrogen-poor medium, which also induces lipid production. These results suggest that R. toruloides can potentially be used for the co-production of lipids and galactitol from galactose. We further characterized the mechanism for galactitol production, including identifying and biochemically characterizing the critical aldose reductase. Intracellular metabolite analysis was also performed to further understand galactose metabolism.
Conclusions
Rhodosporidium toruloides has traditionally been used for the production of lipids and lipid-based chemicals. Our work demonstrates that R. toruloides can also produce galactitol, which can be used to produce polymers with applications in medicine and as a precursor for anti-cancer drugs. Collectively, our results further establish that R. toruloides can produce multiple value-added chemicals from a wide range of sugars.Ope
Scope of Real Time Fluorescence Imaging in Esophagectomy
Esophagectomy is a challenging surgery that is known to be associated with high rates of morbidity. Anastomotic leaks, pneumonia, conduit necrosis and chyle leaks are the commonly reported complications. Perfusion assessment and tissue injection based fluorescence guided surgery (FGS) are the newer clinical applications of fluorescent dyes. With the advent and integration of real time fluorescence imaging with the existing minimal access platforms, the esophageal surgeon can employ these techniques to potentially improve outcomes. During thoracic dissection, thoracic duct lymphography, fluorescence guided airway visualization, tracheal perfusion assessment and sentinel lymph node biopsy/dissection are the reported clinical applications. In the abdominal dissection, gastroepiploic arcade identification, gastric conduit perfusion assessment and proximal esophagus perfusion assessment have been described. Using the different routes of administration, the same dye can be used for different uses at separate points in a single esophagectomy surgery. The principles and evidence pertaining to these applications have been outlined
yuDetecting the percent of peripheral blood mononuclear cells displaying p-STAT-3 in malignant glioma patients
<p>Abstract</p> <p>Background</p> <p>The signal transducer and activator of transcription 3 (STAT-3) is frequently overexpressed in cancer cells, propagates tumorigenesis, and is a key regulator of immune suppression in cancer patients. The presence of phosphorylated STAT-3 (p-STAT-3) in the tumor can induce p-STAT-3 in tumor-associated immune cells that can return to the circulatory system. We hypothesized that the number of peripheral blood mononuclear cells (PBMCs) displaying p-STAT-3 would be increased in glioma patients, which would correlate with the extent of tumor-expressed p-STAT-3, and that higher p-STAT-3 levels in peripheral blood would correlate with a higher fraction of immune-suppressive regulatory T cells (Tregs).</p> <p>Methods</p> <p>We measured the percentage of PBMCs displaying p-STAT-3 in 19 healthy donors and 45 patients with primary brain tumors. The level of p-STAT-3 in tumor tissue was determined by immunohistochemistry. The degree of immune suppression was determined based on the fraction of Tregs in the CD4 compartment.</p> <p>Results</p> <p>Healthy donors had 4.8 ± 3.6% of PBMCs that expressed p-STAT-3, while the mean proportion of PBMCs displaying p-STAT-3 in patients with GBM was 11.8 ± 13.5% (<it>P </it>= 0.03). We did not observe a correlation by Spearman correlation between the degree of p-STAT-3 levels in the tumor and the percent of PBMCs displaying p-STAT-3. Furthermore, the percent of PBMCs displaying p-STAT-3 in glioma patients was not directly correlated with the fraction of Tregs in the CD4 compartment.</p> <p>Conclusion</p> <p>We conclude that the percent of PBMCs displaying p-STAT-3 may be increased in malignant glioma patients.</p
TNF-α promoter polymorphism: a factor contributing to the different immunological and clinical phenotypes in Japanese encephalitis
<p>Abstract</p> <p>Background</p> <p>More than three billion populations are living under the threat of Japanese encephalitis in South East Asian (SEA) countries including India. The pathogenesis of this disease is not clearly understood and is probably attributed to genomic variations in viral strains as well as the host genetic makeup. The present study is to determine the role of polymorphism of TNF-alpha promoter regions at positions -238G/A, -308G/A, -857C/T and -863C/A in the severity of Japanese encephalitis patients.</p> <p>Methods</p> <p>Total of 142 patients including 66 encephalitis case (IgM/RT-PCR positive), 16 fever cases (IgM positive) without encephalitis and 60 apparently healthy individuals (IgG positive) were included in the study. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) using site specific restriction enzymes were implemented for polymorphism study of TNF alpha promoter.</p> <p>Results</p> <p>Following the analysis of the digestion patterns of four polymorphic sites of the TNF- alpha promoter region, a significant association was observed between the allele -308A and -863C with the patients of Japanese encephalitis.</p> <p>Conclusions</p> <p>TNF- alpha 308 G/A has been shown to be associated with elevated TNF- alpha transcriptional activity. On the other hand, polymorphism at position -863C/A in the promoter region has been reported to be associated with reduced TNF- alpha promoter activity and lower plasma TNF levels. As per the literature search, this is the first study to identify the role of TNF- alpha promoter in JE infection. Our results show that subjects with - 308A and -863C alleles are more vulnerable to the severe form of JE infection.</p
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