A Bias-Adjusted LM Test of Error Cross Section Independence

This paper proposes bias-adjusted normal approximation versions of Lagrange multiplier (NLM) test of error cross section independence of Breusch and Pagan (1980) in the case of panel models with strictly exogenous regressors and normal errors. The exact mean and variance of the Lagrange multiplier (LM) test statistic are provided for the purpose of the bias-adjustments, and it is shown that the proposed tests have a standard normal distribution for the fixed time series dimension (T) as the cross section dimension (N) tends to infinity. Importantly, the proposed bias-adjusted NLM tests are consistent even when the Pesaran’s (2004) CD test is inconsistent. The finite sample evidence shows that the bias adjusted NLM tests successfully control the size, maintaining satisfactory power. However, it is also shown that the bias-adjusted NLM tests are not as robust as the CD test to non-normal errors and/or in the presence of weakly exogenous regressors

On the Equal-height Elements of Fuzzy AG-subgroups

Abstract: In this paper we introduce the left (right) equal-height elements of a fuzzy power set. We show that both left and right equal-height elements coincide in fuzzy AG-subgroups. We investigate that the collection of left (right) equal-height elements of AG-group G form an AG-subgroup of . G We also establish a relation between the left equal-height elements and left cosets as well as the right equal-height elements and right cosets of an AG-group

High-temperature magnetic blocking in a monometallic dysprosium azafullerene single-molecule magnet

Single-molecule magnets (SMMs) showing magnetic blocking near or above liquid nitrogen temperature have recently been achieved by inducing exceptionally strong and axial crystal fields via double decker ligands. However, further enhancing the performance at higher temperatures becomes a formidable task. Here we provide an alternative strategy to advance towards this goal by entrapping a single dysprosium(III) ion within a nitrogen-substituted carbon cage. In this structure of Dy@C81N, DyIII is asymmetrically coordinated by one side to a hexagonal carbon ring of the azafullerene, while lacking any coordination ligand on the other side. Despite the very weak crystal field resulting from this very unusual low-coordination environment, this compound exhibits a high blocking temperature (TB, defined as T(t100s)) of 45 K. Its extraordinary magnetic behavior is attributed to the minimal number of vibrations that couple to its spin states, being also responsible for the unusual slow Raman relaxation mechanism observed at high temperatures

Characterization of 6-methoxyflavanone as a novel anxiolytic agent: A behavioral and pharmacokinetic approach.

Benzodiazepines are regularly prescribed for the treatment of anxiety though there are side effects. Flavonoids have selective affinity for GABAA receptors implicated in anxiolytic-like activity in rodents, but are devoid of the unwanted side effects of benzodiazepines. In this study, 6-methoxyflavanone (6-MeOF), a positive allosteric modulator of γ-amino butyric acid (GABA) responses at human recombinant GABAA receptors, was evaluated for its behavioral profile in the elevated plus-maze, as well as the staircase- and open-field tests in mice. In addition, the distribution of 6-MeOF in selected brain areas involved in anxiety (amygdala and cerebral cortex) was also examined using a validated high performance liquid chromatography/ultraviolet detection (HPLC/UV) method. 6-MeOF (10, 30 and 50 mg/kg) exerted an anxiolytic-like effect, increasing entries and time spent in the open arm and the central platform, as well as head-dipping frequency in the mouse elevated plus-maze assay. It also decreased rearing incidence without suppressing the number of steps ascended in the staircase test. Whereas, in the open-field anxiety test, 6-MeOF had no effect on locomotor activity at lower doses, a decrease was observed at the highest dose (100 mg/kg). 6-MeOF additionally produced an anxiolytic-like increase in the time spent at the center of the open-field apparatus. These effects were preferentially antagonized by pentylenetetrazole (15 mg/kg). Furthermore, pharmacokinetic studies disclosed a rapid appearance of 6-MeOF in the plasma and discrete brain areas. Taken together, our findings suggest that 6-MeOF readily crosses the blood brain barrier (BBB) generating anxiolytic activity, mediated through the GABAergic system

Production system and challenges of saline aquaculture in Punjab and Sindh provinces of Pakistan

IntroductionLack of data about saline aquaculture in Pakistan has curtailed informed policy and investment decision making resulting in undervaluation of and underinvestment in the sector. Therefore, saline aquaculture in Pakistan is today an underdeveloped sector despite its potential as an alternative livelihood for the country's rural farmers. This study represents one of the initial exploratory investigations into saline aquaculture systems in Pakistan, aiming to comprehend the existing sectoral landscape, production challenges, post-harvest constraints, and the associated capacity and investment needs.MethodsThe study employed purposive sampling to survey 121 low-income saline aquaculture farmers across five districts of Southern Punjab and Sindh provinces. The analysis was carried out using descriptive statistics.ResultsThe results revealed that the saline aquaculture sector is predominantly male-centric, with agricultural land utilized for both agriculture and aquaculture purposes. Ponds, which usually serve multiple functions, focus primarily on carp production, but adherence to good management practices remains limited. Farmers face various challenges, including the high costs of feed and seeds, freshwater scarcity, inadequate technical knowledge, and marketing issues.Discussion and conclusionThis study serves as a foundational assessment, addressing data and information gaps crucial for supporting the sustainable development of saline aquaculture in Pakistan. To facilitate such development, the study recommends initiating programs to strengthen technical skills in saline aquaculture, together with the establishment of hatcheries and breeding stations for saline-tolerant species, aiming to reduce dependence on freshwater species in saline pond environments

A single amino-acid substitution in the sodium transporter HKT1 associated with plant salt tolerance

A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a Ktransporter in the presence of Na in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (N) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1) complemented K-uptake deficiency of yeast cells. Mutanthkt1-1 plants complemented with both AtHKT1 and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na and Kbased on the N/D variance in the pore region. This change also dictated inward-rectification for Na transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats.Peer Reviewe

A single amino-acid substitution in the sodium transporter HKT1 associated with plant salt tolerance

© 2016 American Society of Plant Biologists. All rights reserved. A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K+ TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na+ from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K+transporter in the presence of Na+ in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (N) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1N-D) complemented K+-uptake deficiency of yeast cells. Mutanthkt1-1 plants complemented with both AtHKT1N-D and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na+ and K+based on the N/D variance in the pore region. This change also dictated inward-rectification for Na+ transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats

GIS-based assessment of selective heavy metals and stable carbon isotopes in groundwater of Islamabad and Rawalpindi, Pakistan

This study applied a nuclear technique in conjunction with a classical monitoring tool to characterize the origin, fate, and behavior of metal pollutants in groundwater of Islamabad-Rawalpindi Metropolitans, which are also known as the “twin cities.” In total, 122 groundwater samples were collected and analyzed in accordance with standard methods. GIS and multivariate statistical analysis were employed for the groundwater vulnerability assessment and source apportionment. The results of the aesthetic parameters indicated that the majority of groundwater sources were tested and were colorless, odorless and tasteless in the “twin cities.” In addition, the findings of this study indicated that the concentration of pH, phosphates, copper, manganese, and zinc were within the drinking water standards in the “twin cities” as stipulated by the World Health Organization (WHO) and Pakistan Standard and Quality Control Authority (PSQCA) at all sampling points in the study area. The groundwater quality was found unsuitable for consumption due to elevated levels of electrical conductivity and total dissolved solids at 9.83% and 4.09% of samples, respectively. The contents of arsenic and fluoride were well within the allowable range at almost all points except at one location. However, iron and lead contents were above permissible limits. A statistical analysis revealed that trace metals originated from both geogenic and anthropogenic sources such as enhanced rock-water interaction, over abstraction, evaporation enrichment, improper waste disposal, discarded batteries, cross contamination of water supply and sewerage lines, active recharge from Lie drain, and domestic, industrial, and agricultural effluents. The computed water quality index (WQI) based on heavy metals elucidated that groundwater quality was poor in most of the study area due to elevated electrical conductivity, total dissolved solids, lead, iron, arsenic, and fluoride values. A highly depleted isotopic composition of 13C provides clues about the aquifer’s vulnerability from miscellaneous sources such as domestic, urban, construction, and agricultural sites and the dissolution of carbonate minerals. This study clearly indicates that a rapidly growing population, unplanned urbanization, industrialization, improper waste disposal, over abstraction, and a lack of water abstraction policies are significantly contributing toward the impairment of groundwater quality in the study area. The study strongly emphasized the need to regulate groundwater abstraction by improving water treatment and the supply system for the provision of safe water to the urban populace. These results will help in designing remedial strategies for improving water quality in the “twin cities.

A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance

A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K(+) TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na(+) from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K(+) transporter in the presence of Na(+) in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (n) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1(N-D)) complemented K(+)-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1(N)(-)(D) and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na(+) and K(+) based on the n/d variance in the pore region. This change also dictated inward-rectification for Na(+) transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats