Changing Bases: Multistage Optimization for Matroids and Matchings

This paper is motivated by the fact that many systems need to be maintained continually while the underlying costs change over time. The challenge is to continually maintain near-optimal solutions to the underlying optimization problems, without creating too much churn in the solution itself. We model this as a multistage combinatorial optimization problem where the input is a sequence of cost functions (one for each time step); while we can change the solution from step to step, we incur an additional cost for every such change. We study the multistage matroid maintenance problem, where we need to maintain a base of a matroid in each time step under the changing cost functions and acquisition costs for adding new elements. The online version of this problem generalizes online paging. E.g., given a graph, we need to maintain a spanning tree $T_t$ at each step: we pay $c_t(T_t)$ for the cost of the tree at time $t$, and also $| T_t\setminus T_{t-1} |$ for the number of edges changed at this step. Our main result is an $O(\log m \log r)$-approximation, where $m$ is the number of elements/edges and $r$ is the rank of the matroid. We also give an $O(\log m)$ approximation for the offline version of the problem. These bounds hold when the acquisition costs are non-uniform, in which caseboth these results are the best possible unless P=NP. We also study the perfect matching version of the problem, where we must maintain a perfect matching at each step under changing cost functions and costs for adding new elements. Surprisingly, the hardness drastically increases: for any constant $\epsilon>0$, there is no $O(n^{1-\epsilon})$-approximation to the multistage matching maintenance problem, even in the offline case

Molecular characterization of ten mango cultivars using simple sequences repeat (SSR) markers

Simple sequence repeats (SSRs) which is an efficient genetic markers for comparative genome mapping can be helpful in the classification of genotypes, germplasm resource utilization and breeding programmes. Therefore, the present study was conducted to show genetic variation and investigate inter-relationship between ten mango genotypes. Twenty (20) SSR markers were tested with 10 genotypes: Kalepad, Neelum, Swarnarekha, Alphonso Rumani, Sendura, Banganapalli, Himayuddin, Mulgoa and Bangalora. The genomic DNA was extracted from the leaf samples using cetyltrimethyl ammonium bromide (CTAB) method. Polymerase chain reaction (PCR) amplification of the DNA isolated from 10 mango genotypes with 20 SSR primers produced a total of 240 amplified products, of which 184 were polymorphic and 56 monomorphic. The sizes of the alleles detected ranged from 120 to 369 bp. SSR markers were highly polymorphic with an average of 2.70 alleles per primers. SSRs gave moderate values of polymorphic information content (PIC) range of 0.320 to 0.774. The amplified products varied between 2 (LMMA 1, 5, 7, 12, 16, MiSHRS-1 and MiSHRS-37) to 3 and 4 (LMMA 4, 6, 9, 10, 11, 13, 14, 15 MiSHRS-4, 48, 18, 39 and LMMA 8) bands per primer. We obtained moderate degree of genetic diversity, with Jaccard’s similarity co-efficient values ranging from 0.075 between cluster I and II to 0.285 between clusters II and III. The dendrogram generated from the unweighted pair group arithmetic average (UPGMA) cluster analysis broadly placed 10 mango cultivars into three major clusters at co-efficient similarity of 0.65. The cluster size varied from 1 to 6 and cluster III was the largest cluster comprising of six cultivars followed by cluster II possessing three and cluster I possessing one variety. Cluster I had the highest diverse cultivars namely, Kalepad, Neelum and Swarnarekha. Cluster II included cultivar of Alphonso. Cluster III contain the cultivars viz., Rumani, Sendura, Bangnapalli, Himayuddin, Mulgoa and Bangalora. Unique fingerprints were identified in the cultivars. The unique fingerprints size ranged from LMMA-8 (257-270 bp), LMMA-11 (232- 245 bp) to MiSHRS 39 (340-369 bp). The tendency of clustering among mango cultivars revealed that they have strong affinity towards further breeding programme.Key words: Cultivars, genetic diversity, mango, simple sequence repeats (SSR)

Coexistence of orbital and quantum critical magnetoresistance in FeSe1−x_{1-x}Sx_{x}

The recent discovery of a non-magnetic nematic quantum critical point (QCP) in the iron chalcogenide family FeSe$_{1-x}$S$_{x}$ has raised the prospect of investigating, in isolation, the role of nematicity on the electronic properties of correlated metals. Here we report a detailed study of the normal state transverse magnetoresistance (MR) in FeSe$_{1-x}$S$_{x}$ for a series of S concentrations spanning the nematic QCP. For all temperatures and \textit{x}-values studied, the MR can be decomposed into two distinct components: one that varies quadratically in magnetic field strength $\mu_{0}\textit{H}$ and one that follows precisely the quadrature scaling form recently reported in metals at or close to a QCP and characterized by a \textit{H}-linear MR over an extended field range. The two components evolve systematically with both temperature and S-substitution in a manner that is determined by their proximity to the nematic QCP. This study thus reveals unambiguously the coexistence of two independent charge sectors in a quantum critical system. Moreover, the quantum critical component of the MR is found to be less sensitive to disorder than the quadratic (orbital) MR, suggesting that detection of the latter in previous MR studies of metals near a QCP may have been obscured.Comment: 19 pages (including Supplemental Material), 12 figure

Fusion barrier distributions in systems with finite excitation energy

Eigen-channel approach to heavy-ion fusion reactions is exact only when the excitation energy of the intrinsic motion is zero. In order to take into account effects of finite excitation energy, we introduce an energy dependence to weight factors in the eigen-channel approximation. Using two channel problem, we show that the weight factors are slowly changing functions of incident energy. This suggests that the concept of the fusion barrier distribution still holds to a good approximation even when the excitation energy of the intrinsic motion is finite. A transition to the adiabatic tunneling, where the coupling leads to a static potential renormalization, is also discussed.Comment: 9 pages, 4 figures, Submitted to Physical Review

Trend analysis and variability of satellite-based soil moisture data for the Lower Bhavani basin, Tamil Nadu using Google Earth Engine

Soil moisture is a significant hydrological component that is dynamic in nature. The variation in soil moisture in the basin scale would affect the vegetation, ecology and environment. Soil moisture trend analysis aids in providing the variation of soil moisture over the basin. The present study aimed to analyse the soil moisture trend in Lower Bhavani basin, Tamil Nadu from 2003-2022. Satellite-based soil moisture Global Land Data Assimilation System (GLDAS) data was extracted from the Google Earth Engine (GEE) platform to analyse the variation and trend over the period of time. The highest and lowest soil moisture was observed during monsoon and summer months and its percentage variation was studied. Using Man-Kendall test and Sen’s slope, trend analysis was calculated for two decades (2003-2012 and 2013-2022). In 2003-2012, an increasing trend of soil moisture was observed during winter (October to February); from 2013-2022, an increasing trend was observed during both winter (October to February) and monsoon seasons (June to September). The remaining season did not follow any trend, and there was no decreasing trend in soil moisture. The trend analysis of the study will help to monitor and manage the environmental system across the Lower Bhavani basin

Orange grower's perception of drought impacts and strategies for mitigation and adaptation: A study of the Vidarbha region in India

This is the final version. Available on open access from Elsevier via the DOI in this record. Data availability: Data will be made available on request.Vidarbha, a region in Maharashtra, India, is famous for its sweet-sour-flavoured Nagpur Orange. Vidarbha is witnessing droughts after every alternate year resulting in crop failure and causing distress to orange growers. The present study attempts to – 1) identify critical challenges Vidarbha orange growers face during drought impact and 2) examine the farmers' perception and awareness about drought impacts, and different adaptation and mitigation strategies in practice at the farmer's level. This research used a field study approach in the drought-prone Vidarbha region to acquire orange farmers' perceptions of the drought impact. We have used a three-stage method to carry out this study. In the first stage, a Delphi method is adopted to identify and validate orange growers' challenges due to drought impact. The second stage comprises utilising multi-criteria decision-making (MCDM)-based best-worst method to prioritise and determine the most critical challenges. This is followed by descriptive statistical analysis in the third stage to determine the overall perception of orange growers about drought and its adaptation and mitigation strategies. It is observed through findings that – “inadequate water bodies, lack of availability of capital, and high cost of drip irrigation” are critical challenges orange growers witness during drought. While “installing an efficient irrigation system and pest control” are the adaptation strategies, and “seeking guidance from the agriculture department” and “reliance on weather forecast” are the mitigation strategies widely adopted by Nagpur orange growers to alleviate drought stress.University of Exete

Augmenting EV charging infrastructure towards transformative sustainable cities: An equity-based approach

This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: We maintain all dataset, code and interactive visualizaiton for this paper in an open repository. This can be accessed at: https://doi.org/10.5281/zenodo.8335314An increasing number of studies have reported on the need to augment public electric vehicle (EV) charging points (E-CPs) in areas with growing demand for parking. However, the focus on E-CP infrastructure equity has largely been ignored. For increased uptake of EVs, we argue that future E-CP infrastructure augmentation (EIA) will necessitate the identification of the optimal locations based on a need-focused strategic approach. Our work utilises open datasets and presents a generic multicriteria-based modelling framework for EIA framework. The E-CP Infrastructure Framework a two-stage framework. The first stage assesses the existing infrastructure gap and spatial disparity of E-CP allocation at the city scale. Next, guided by the information from stage one, stage two identifies the optimal E-CP candidate locations for future EIA expansion. The locations are determined using a parametric scoring approach that includes ease of access, available bays for parked vehicles, and potential congestion risk. We take the example of Dresden city to demonstrate the applicability of the EIA framework. Our findings show the wide prevalence of spatial disparities in E-CPs across nine of the ten wards in the city. Our proposed city-scale approach for identifying candidate locations could help policymakers decide on the augmentation strategies of E-CP infrastructure in a spatially equitable and cost-effective manner

Correlation of Clinical Neuromusculoskeletal and Central Somatosensory Performance: Variability in Controls and Patients With Severe and Mild Focal Hand Dystonia

Focal hand dystonia (FHd) is a recalcitrant, disabling movement disorder, characterized by involuntary co-contractions of agonists and antagonists, that can develop in patients who overuse or misuse their hands. The aim of this study was to document clinical neuromusculoskeletal performance and somatosensory responses (magnetoencephalography) in healthy controls and in FHd subjects with mild versus severe hand dystonia. The performance of healthy subjects (n = 17) was significantly better than that of FHd subjects (n = 17) on all clinical parameters. Those with mild dystonia (n = 10) demonstrated better musculoskeletal skills, task-specific motor performance, and sensory discrimination, but the performance of sensory and fine motor tasks was slower than that of patients with severe dystonia. In terms of somatosensory evoked field responses (SEFs), FHd subjects demonstrated a significant difference in the location of the hand representation on the x and y axes, lower amplitude of SEFs integrated across latency, and a higher ratio of mean SEF amplitude to latency than the controls. Bilaterally,. those with FHd (mild and severe) lacked progressive sequencing of the digits from inferior to superior. On the affected digits, subjects with severe dystonia had a significantly higher ratio of SEF amplitude to latency and a significantly smaller mean volume of the cortical hand representation than those with mild dystonia. Severity of dystonia positively correlated with the ratio of SEF mean amplitude to latency (0.9029 affected, 0.8477 unaffected; p<0.01). The results of the present study strengthen the evidence that patients with FHd demonstrate signs of somatosensory degradation of the hand that correlates with clinical sensorimotor dysfunction, with characteristics of the dedifferentiation varying by the severity of hand dystonia. If these findings represent aberrant learning, then effective rehabilitation must incorporate the principles of neuroplasticity. Training must be individualized to each patient to rebalance the sensorimotor feedback loop and to restore normal fine motor control

Applicability of the orientation average formula in heavy-ion fusion reactions of deformed nuclei

In heavy-ion fusion reactions involving a well deformed nucleus, one often assumes that the orientation of the target nucleus does not change during the reaction. We discuss the accuracy of this procedure by analyzing the excitation function of the fusion cross section and the fusion barrier distribution in the reactions of $^{154}$Sm target with various projectiles ranging from $^{12}$C to $^{40}$Ar. It is shown that the approximation gradually looses its accuracy with increasing charge product of the projectile and target nuclei because of the effects of finite excitation energy of the target nucleus. The relevance of such inaccuracy in analyzing the experimental data is also discussed.Comment: 5 pages and 3 figure

Cultural adaptation of Alzheimer’s disease assessment scale–cognitive subscale for use in India and validation of the Tamil version for South Indian population

Objective: Currently no standardized tools are available in the Indian languages to assess changes in cognition. Our objectives are to culturally adapt the Alzheimer’s disease Assessment Scale–Cognitive Subscale (ADAS-Cog) for use in India and to validate the Tamil version in an urban Tamil-speaking older adult population. / Methods: Two panels of key stakeholders and a series of qualitative interviews informed the cultural and linguistic adaptation of the ADAS-Cog-Tamil. Issues related to levels of literacy were considered during the adaptation. Validation of the ADAS-Cog-Tamil was completed with 107 participants − 54 cases with a confirmed diagnosis of mild-moderate dementia, and 53 age, gender and education matched controls. Concurrent validity was examined with the Vellore Screening Instrument for Dementia (VSID) in Tamil. Internal consistency using Cronbach’s alpha, sensitivity and specificity data using the Area under the Receiver Operating Characteristics (AUROC) curve values were computed. Inter-rater reliability was established in a subsample. / Results: The ADAS-Cog-Tamil shows good internal consistency (α = 0.91), inter-rater reliability and concurrent validity (with VSID-Patient version: r = –0.84 and with VSID-Caregiver version: r = –0.79). A cut-off score of 13, has a specificity of 89% and sensitivity of 90% for the diagnosis of dementia. / Conclusion: ADAS-Cog-Tamil, derived from a rigorous, replicable linguistic and cultural adaptation process involving service users and experts, shows good psychometric properties despite the limitations of the study. It shows potential for use in clinical settings with urban Tamil speaking populations. The English version of the tool derived from the cultural adaptation process could be used for further linguistic adaptation across South Asia