Tensor to Scalar Ratio in Non-Minimal ϕ4\phi^4 Inflation

We reconsider non-minimal \lambda \phi^4 chaotic inflation which includes the gravitational coupling term \xi \mathcal{R} \phi^2, where \phi denotes a gauge singlet inflaton field and \mathcal{R} is the Ricci scalar. For \xi >> 1 we require, following recent discussions, that the energy scale \lambda^{1/4} m_P / \sqrt{\xi} for inflation should not exceed the effective UV cut-off scale m_P / \xi, where m_P denotes the reduced Planck scale. The predictions for the tensor to scalar ratio r and the scalar spectral index n_s are found to lie within the WMAP 1-\sigma bounds for 10^{-12} < \lambda < 10^{-4} and 10^{-3} < \xi < 10^2. In contrast, the corresponding predictions of minimal \lambda \phi^4 chaotic inflation lie outside the WMAP 2-\sigma bounds. We also find that r > 0.002, provided the scalar spectral index n_s > 0.96. In estimating the lower bound on r we take into account possible modifications due to quantum corrections of the tree level inflationary potential.Comment: 10 pages, 6 figure

Towards Security of GSM Voice Communication

Global system for mobile communication (GSM) is widely used digital mobile service around the world. Although GSM was designed as a secure wireless system, it is now vulnerable to different targeted attacks. There is a need to address security domains especially the confidentiality of communication. This paper presents a novel framework for end to end secure voice communication over the GSM networks using encryption algorithm AES-256. A special Modem and speech coding technique are designed to enable the transmission of encrypted speech using GSM voice channel. To the best of our knowledge, this is first solution that uses single codebook for transmission of secure voice. An efficient low bit-rate (1.9 kbps) speech coder is also designed for use with the proposed modulation scheme for optimal results. Different speech characteristics such as pitch, energy and line spectral frequencies are extracted and preserved before compression and encryption of speech. Previously, the best achieved data rate was 1.6 kbps with three codebooks, whilst the proposed approach achieves 2 kbps with 0% bit error rate. The empirical results show that the methodology can be used for real time applications to transmit encrypted voice using GSM network

Effect of Mercury on Seed Germination and Seedling Growth of Mungbean (Vigna radiata (L.) Wilczek)

Among the toxic elements release in the environment, mercury is considered highly toxic to the growth of plants. The present studies report the effects of different concentrations (1, 3, 5 and 7 mM) of mercury on seed germination and seedling growth performance of mungbea (Vigna radiata) as compared to control. Mercury treatment in the form of mercuric chloride at 1 mM did not show significant reduction in seed germination of V. radiata as compared to control. Increase in  concentration of mercury to 3 mM produced significant (p&lt;0.05) reduction in seed germination. Mercury treatment at 7 mM-produced significant (p&lt;0.05)  reduction in seedling and root length of the plants. The increase in concentration of mercury treatment at 7 mM was found sufficient to cause significant reductions in seedling dry weight of as compared to control. Mercury treatment at all concentrations decreased seed germination, shoot, and root length and seedling dry weight. Increase in mercury concentration upto 7 mM showed highest percentage of decrease in seed germination (42%), seedling length (70%), root length  (66%) and seedling dry weight (47%) of mungbean as relation to control. V. radiata were more sensitive to mercury stress in seedling growth and root elongation than seed germination. The seedlings of V. radiata showed greater tolerance to mercury at 1 mM (85.83 %) and lowest at 7 mM (34.13%). These results show that there is a negative effect towards germination and growth of mungbean by mercury treatment. Minimum use of the mercury containing compounds in fungicide,  pesticide and nematicide is recommended. Special care should be taken to monitor the toxic pollutants available in the immediate environment. The accumulation of such types of toxic pollutants in larger concentrations by crop can produce harmful effects to crops and ecosystem as well

Analysis of landslide movements using interferometric synthetic aperture radar: A case study in Hunza-Nagar Valley, Pakistan

From a geological standpoint, northern Pakistan is one of the most active and unstable areas in the world. As a consequence, many massive landslides have occurred in the area in historical times that have destroyed infrastructure, blocked the Hunza River, and damaged the Karakoram Highway repeatedly. However, despite the high frequency of large magnitude landslide events, and the consequent damages, the entire area is largely understudied, mainly due to the difficult logistics and the large distances involved. This work is aimed at applying the potential use of Interferometric Synthetic Aperture Radar (InSAR) for landslide identification and investigation for the Hunza-Nagar Region. Sentinel-1 images covering a period of more than two years (February 2017-August 2019) were used and processed by adopting the small baseline subset (SBAS) method. The obtained deformation rate measured along the line of sight (VLOS) varies from -114 to 20 mm/year. The downslope velocity deformation rates (Vslope) range from 0 to -300 mm/year. The Vslope stability threshold for our study area was calculated to be -14 mm/year from the Vslope standard deviation. Four active landslides with Vslope exceeding 14 mm/year were recognizable and have been confirmed by field inspection. The identified landslides listed from the most active to least active are the Humarri, Mayoon, Khai, and Ghulmet landslides, respectively. VLOS exceeding 114 mm/year was observed in the Humarri landslide, which posed a threat of damming a lake on the Hispar River and was also a risk to the Humarri Village located below the landslide. The maximum mean deformation detected in the Ghulmet, andMayoon landslide was in the order of 30 mm/year and 20 mm/year, respectively. More importantly, it was found that in places, the slope deformation time series showed a patchy correlation with precipitation and seismic events in the area. This may indicate a complex, and possibly uncoupled, relationship between the two controlling agents promoting the deformation. However, the collective impact of the two factors is evident in the form of a continuously descending deformation curve and clearly indicates the ground distortion. The results indicate a potentially critical situation related to the high deformation rates measured at the Humarri landslide. On this specific slope, conditions leading to a possible catastrophic failure cannot be ruled out and should be a priority for the application of mitigation measures

Corporate capital structure effects on corporate performance pursuing a strategy of innovation in manufacturing companies

Within the sphere of finance, the concept of capital structure has long been a subject of intense debate, serving as a quantitative depiction of the balance between debt, preference shares, and common stock within a company. This structure serves a crucial role in optimizing the utilization of a company's existing resources while simultaneously elevating the revenue streams for stakeholders. This particular study delves into the intricate relationship between corporate performance and capital structure, focusing on 78 publicly listed firms within the Dhaka Stock Exchange (DSE). Bangladesh holds the 29th position globally in terms of purchasing power, lending significant weight to this investigation. To comprehensively analyze this correlation, panel data encompassing the span from 2017 to 2021 was collected for these 78 sample companies operating within the DSE. Several key determinants of capital structure were considered in this analysis, namely the debt-to-equity ratio, short-term leverage ratio, long-term leverage ratio, and total debt ratio. Meanwhile, the performance of these firms was gauged using key metrics such as Return on Assets (ROA), Return on Equity (ROE), and Earnings Per Share (EPS). To ensure a robust analysis, factors such as inflation, liquidity, growth rate, tax rate, and firm size were meticulously controlled for. The findings unveiled a compelling narrative: all forms of debt ratios—be it short-term, long-term, or the total debt ratio—exhibited a substantial negative impact on ROA at a significant level of 1 %. Conversely, specific debt ratios, like the short-term total debt and the total debt-to-total asset ratio, displayed a notable positive correlation with ROE at a 1 % significance level. Intriguingly, the long-term total debt ratio yielded a negative and insignificant effect on ROE. Moreover, within the spectrum of predictors influencing a firm's performance, the liquidity ratio emerged as a non-significant factor—a notable discovery that highlights the nuanced nature of the interplay between capital structure and performance within these companies.</p

Why do patients with limb ischaemia present late to a vascular surgeon? A prospective cohort study from the developing world

OBJECTIVE: To look into the factors responsible for delay in presentation of Iimb ischemia patients to a vascular surgeon. METHODS: The prospective cohort study was conducted at the Aga Khan University Hospital, Karachi, from October 01, 2016, to August 10, 2018. Patients coming with delayed presentation of both acute and chronic limb ischemia were included. All the patients were assessed by qualified vascular surgeons. SPSS 23 was used for data analysis. RESULTS: Of the 55 patients, 33(60%) had acute and 22(40%) had chronic limb ischaemia. Mean age of acute cases was 44±23.72 years and it was 60±12.49 years for chronic cases. Overall, the commonest reason behind delay was non-referral by primary physician which was the case with 11(33.3%) patients in the acute group, and 13(59%) in the chronic group. The limb loss in the acute group was 20(60%) and 8(36%) in the chronic group.. CONCLUSION: Delayed presentation of patients with limb ischaemia is mainly due to non-referral. A robust campaign needs to be launched to reduce the rate of limb loss