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Let A and S be the adjacency and the Seidel matrix of a graph G respectively. A-energy is the ordinary energy E(G) of a graph G defined as the sum of the absolute values of eigenvalues of A. Analogously, S-energy is the Seidel energy ES(G) of a graph G defined to be the sum of the absolute values of eigenvalues of the Seidel matrix S. In this article, certain class of A-equienergetic and S-equienergetic graphs are presented. Also some linear relations on A-energies and S-energies are given.

The spectral polynomial of a graph is the characteristic polynomial of its adjacency matrix. Spectral polynomial of the splice and links of complete graph and star have been obatined recently in the literature. In this paper we generalize these results using the concept of equitable partition.

Exciton-polaritons are typically formed in organic systems when the molecules are confined between metallic or dielectric mirrors. Here, the authors reveal that interactions between excitons and moderately confined photonic states within the bare organic film can also lead to polariton formation, making them the primary photoexcitation.

Aversive geofencing devices (AGDs) or animal-borne satellite-linked shock collars might become a useful tool to mitigate human-elephant conflict (HEC). AGDs have the potential to condition problem elephants to avoid human-dominated landscapes by associating mild electric shocks with preceding audio warnings given as they approach virtual boundaries. We assessed the opinions of different stakeholders (experts, farmers, and others who have and have not experienced HEC; n = 611) on the potential use of AGDs on Asian elephants. Most respondents expressed positive opinions on the potential effectiveness of AGDs in managing elephant movement (62.2%). About 62.8% respondents also provided positive responses for the acceptability of AGDs if pilot studies with captive elephants have been successful in managing their movements. Some respondents perceived AGDs to be unacceptable because they are unethical or harmful and would be unsuccessful given wild elephants may respond differently to AGDs than captive elephants. Respondents identified acceptability, support and awareness of stakeholders, safety and wellbeing of elephants, logistical difficulties, durability and reliable functionality of AGDs, and uncertainties in elephants’ responses to AGDs as potential challenges for implementing AGDs. These issues need attention when developing AGDs to increase support from stakeholders and to effectively reduce HEC incidents in the future.

Objective Challenges in susceptibility testing of colistin along with increase in the prevalence of colistin-resistant carbapenemase-producing Enterobacteriaceae (CRE) pathogens needs addressal. Evaluation of user-friendly methods is necessary as an alternative to broth microdilution (BMD), the reference susceptibility testing method, for routine implementation in diagnostic clinical microbiology laboratories. Genotypic detection of the plasmid-mediated colistin resistance is also needed for infection control purposes. Materials and Methods Colistin susceptibility of 200 nonduplicate clinical CRE isolates from December 2017 to June 2019 was determined by BMD, agar dilution (AD), E test, and rapid polymyxin NP test and interpreted as per the European Committee on Antimicrobial Susceptibility Testing. The results of AD, E test, and NP test were compared with that of BMD, considering minimal inhibitory concentration (MIC) ≤ 2 µg/mL as susceptible and > 2 µg/mL as resistant. Presence of any plasmid-mediated colistin resistance (mcr-1 and 2) was evaluated in 27 colistin-resistant CRE isolates by polymerase chain reaction. Statistical Analysis Performance of different phenotypic methods was analyzed by comparing MIC results of AD and E test with that of reference BMD method. Agreement between BMD and the other two methods was expressed in terms of categorical agreement and essential agreement. Errors were expressed as very major error (VME: false-susceptible) and major error (ME: false-resistance) by AD/E test. VME and ME of 3% disagreement were considered unacceptable. Results Colistin resistance was found in 27 (13.5%) isolates by BMD method. The VME rates of both AD (11%) and E test (37%) could not meet the Clinical and Laboratory Standards Institute recommendation (< 3% VME rate is acceptable) as alternative tests to the reference BMD. Colistin NP test showed sensitivity and specificity of 85% and 98%, respectively. The percentage discordant result in NP test was highest in Enterobacter spp. (17%). None of the 27 colistin resistant isolates showed presence of mcr-1 and mcr-2 genes. Conclusion High VME rate in AD and E tests precludes their use as alternatives to BMD for colistin susceptibility testing. NP test with moderate sensitivity but excellent specificity can be a good alternative for testing colistin susceptibility in CRE isolates, except in Enterobacter spp. Absence of mcr-1 and mcr-2 gene necessitates the exploration of other mechanisms of colistin resistance.

Background Spread of carbapenem-resistant Enterobacterales (CRE) is a significant concern in intensive care unit (ICU) settings. Approaches to routine screening for CRE colonization in all ICU patients vary depending on institutional epidemiology and resources. The present study was aimed to evaluate the performance of HiCrome Klebsiella pneumoniae carbapenemase (KPC) agar for the detection of CRE colonization in ICU settings taking the Centers for Disease Control and Prevention (CDC) recommended method as reference. Methods Two-hundred and eighty rectal swabs (duplicate) from 140 patients were subjected to CRE detection in HiCrome KPC agar and MacConkey agar (CDC criteria). Results Using CDC method, total 41 CRE isolates were recovered comprising of 29 Escherichia coli, 11 Klebsiella, and 1 Enterobacter spp. On the other hand, 49 isolates of CRE recovered from 140 rectal swabs using HiCrome KPC agar, out of which 33 were E. coli, 15 Klebsiella, and 1 Enterobacter sp. Statistical Analysis Sensitivity, specificity, negative, and positive predictive values of CRE screening by HiCrome KPC agar were found to be 100% (91.4–100), 91.9% (84.8–95.8), 83.6% (70.9–91.4), and 100% (95.9–100), respectively, taking the CDC recommended method as reference. Conclusion HiCrome KPC agar has high sensitivity in screening CRE colonization. Further studies are needed to establish its applicability for detecting the predominant circulating carbapenemases in the Indian setting.