Higher Order Approximation for Stimulated Raman Scattering Including Walk-off Effect

The performance of an optical system is reduced by nonlinear effects. It is known that when optical power is very high then non linear effects tend to manifest themselves, so the study became important in DWDM system. The fiber nonlinearities fall into two categories. One is stimulated scattering (Raman and Brillouin), and the second is known as optical Kerr effect. With these effects the results are changed in the refractive index of fiber with optical power. With different input signals kerr-non-linearity manifests itself in three different effects such as Self-Phase Modulation (SPM), Cross-Phase Modulation (CPM) and Four-Wave Mixing (FWM). At high power level, the inelastic scattering phenomenon can induce stimulated effects such as Stimulated Brillouin-Scattering (SBS) and Stimulated Raman-Scattering (SRS). The Brillouin and Raman scattering can be differentiated as the Brillouin generated phonons (acoustic) are coherent and give rise to a macroscopic acoustic wave in fiber, while in Raman scattering the phonons (optical) are incoherent and no macroscopic wave is generated, So SRS is much less problem than SBS. The threshold of SRS is nearly to 1 Watt, more than thousand times higher than SBS. But the real systems are being expanded with EDFAs having output optical powers of 500 mW (+27 dBm), and this will only go higher. A fiber optic link that includes three such optical amplifiers will reach this limit since the limit drops proportionally by the number of optical amplifiers in series

Measuring Growth and Impact of Neuroscience Researches in India: A Scientometric analysis based on Scopus

Present study focuses on growth of neuroscience research in India and its impact on scholarly world. Total 4812 data were collected from Scopus database for the period of 2004-2018. Analysis of the data revealed considerable increase in Annual Growth Rate in neuroscience research with 10.52% CAGR for the entire period. Relative Growth Rate (RGR) was increasing with minor fluctuations i.e. growth in Neuroscience research is not exponential ratio rather than it is arithmetic ratio and Doubling Time is similar to RGR. Trend (Least Square) of the neuroscience publications showed an increase trend during the study period. But the prediction of the trend up to the year 2023 has indicated the downward trend in the growth. Articles were the major form of publication followed by letters. Collaborative Index (CI) ranges from 4.22 to 5.02 with an average of 4.75 per joint authored papers. Degree of collaboration for total publications of the neuroscience was 0.93 i.e. team research, which is confirmed by the value of Collaboration coefficient. Mega-authored papers received highest 24657 (49.88%) citations, whereas single authored papers received lowest 861(1.74%) citations. Author Shukla, D. is the most productive author contributing 42 articles.1934 (40.19%) of total publications did not have any institutional collaboration, 1063 (22.09%) publications were co-authored with other institutes/universities/colleges of India, 764 (15.88%) were collaborated within their own organization/institute/university/college in which they are affiliated and 1051 (21.84%) publications were collaborated with foreign authors

Changing Scholarly Trends of LIS Research in Asia: A Scientometric Study based on Scopus

Scientometric studies can be of great help not only for researchers and academicians but also for the government officials in setting funds for development as well as policy setting and decision making. Various scientometric studies are being done to assess the publication output of the researchers in the various disciplines, to know their collaboration as well as interdisciplinarity. This present study is furthering the level of the study by assessing the LIS research trend in the Asian countries, using AGR, RCI, CC and PEI etc. as indicators

Kalman Filter Based Approach of a signal by removing ICI for OFDM Channel

Abstract— This paper deals with the case of a high speed mobile receiver operating in an orthogonal-frequency division multiplexing (OFDM) communication system. The OFDM communication is very much inspired from the channel frequencies over the network. In such network some kind of orthogonal distortion occurs over the channel called Inter carrier Interference. Here we will improve the ICI using Kalman Filtering improved by using repetitive slot and correlated channel tap. The proposed work of this paper is when data travel over some channel it suffers from the problem of interference. The interference results the high signal to noise ratio as well as high bit error rate. The proposed system will improved the signal by removing the different kind of impurities over the signal. These impurities include the ICI, PAPR and the noise over the signal. The signal will be more effective than standard OFDM. So we needn't many pilot symbols in practice, still can ensure the algorithm performance and reduce the time- delay and complexity of this algorithm

Experimental and Numerical Investigations of Deep Drawability of AA1200

The ability of a sheet metal to be formed in a given process without failure is known as formability. Formability is a measure of the amount of deformation a material can withstand prior to fracture or excessive thinning. Forming Limit Diagram (FLD) is a graphical representation of limit strains at which necking/fracture occurs in a sheet metal under all possible modes of deformation. Anisotropy is the variation in properties with respect to directions, due to variations in microstructures introduced in forming operations such as rolling. The values of strength (YS and UTS) and ductility (% elongation) show a large variation in mechanical properties because of the differences in as rolled specimens, annealed specimens, and different thickness of the Al sheets. From the LDH test the limiting strain values and the formability of sheet metal were found to increases with increasing sheet thickness

A ground-based near-infrared emission spectrum of the exoplanet HD 189733b

Detection of molecules using infrared spectroscopy probes the conditions and compositions of exoplanet atmospheres. Water (H2O), methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) have been detected in two hot Jupiters. These previous results relied on space-based telescopes that do not provide spectroscopic capability in the 2.4 - 5.2 micron spectral region. Here we report ground-based observations of the dayside emission spectrum for HD 189733b between 2.0-2.4 micron and 3.1-4.1 micron, where we find a bright emission feature. Where overlap with space-based instruments exists, our results are in excellent agreement with previous measurements. A feature at ~3.25 micron is unexpected and difficult to explain with models that assume local thermodynamic equilibrium (LTE) conditions at the 1 bar to 1 x 10-6 bar pressures typically sampled by infrared measurements. The most likely explanation for this feature is that it arises from non-LTE emission from CH4, similar to what is seen in the atmospheres of planets in our own Solar System. These results suggest that non-LTE effects may need to be considered when interpreting measurements of strongly irradiated exoplanets.Comment: 12 pages, 2 figures, published in Natur

Aspects of the political economy of development and synthetic biology

What implications might synthetic biology’s potential as a wholly new method of production have for the world economy, particularly developing countries? Theories of political economy predict that synthetic biology can shift terms of trade and displace producers in developing countries. Governments, however, retain the ability to mitigate negative changes through social safety nets and to foster adaptation to some changes through research, education and investment. We consider the effects the synthetic production of otherwise naturally derived molecules are likely to have on trade and investment, particularly in developing countries. Both rubber in Malaysia and indigo dyes in India provide historical examples of natural molecules that faced market dislocations from synthetic competitors. Natural rubber was able to maintain significant market share, while natural indigo vanished from world markets. These cases demonstrate the two extremes of the impact synthetic biology might have on naturally derived products. If developing countries can cushion the pain of technological changes by providing producers support as they retool or exit, the harmful effects of synthetic biology can be mitigated while its benefits can still be captured

Functional Cure of SIVagm Infection in Rhesus Macaques Results in Complete Recovery of CD4+ T Cells and Is Reverted by CD8+ Cell Depletion

Understanding the mechanism of infection control in elite controllers (EC) may shed light on the correlates of control of disease progression in HIV infection. However, limitations have prevented a clear understanding of the mechanisms of elite controlled infection, as these studies can only be performed at randomly selected late time points in infection, after control is achieved, and the access to tissues is limited. We report that SIVagm infection is elite-controlled in rhesus macaques (RMs) and therefore can be used as an animal model for EC HIV infection. A robust acute infection, with high levels of viral replication and dramatic mucosal CD4+ T cell depletion, similar to pathogenic HIV-1/SIV infections of humans and RMs, was followed by complete and durable control of SIVagm replication, defined as: undetectable VLs in blood and tissues beginning 72 to 90 days postinoculation (pi) and continuing at least 4 years; seroreversion; progressive recovery of mucosal CD4+ T cells, with complete recovery by 4 years pi; normal levels of T cell immune activation, proliferation, and apoptosis; and no disease progression. This “functional cure” of SIVagm infection in RMs could be reverted after 4 years of control of infection by depleting CD8 cells, which resulted in transient rebounds of VLs, thus suggesting that control may be at least in part immune mediated. Viral control was independent of MHC, partial APOBEC restriction was not involved in SIVagm control in RMs and Trim5 genotypes did not impact viral replication. This new animal model of EC lentiviral infection, in which complete control can be predicted in all cases, permits research on the early events of infection in blood and tissues, before the defining characteristics of EC are evident and when host factors are actively driving the infection towards the EC status

Tolfenamic Acid Induces Apoptosis and Growth Inhibition in Head and Neck Cancer: Involvement of NAG-1 Expression

Nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1) is induced by nonsteroidal anti-inflammatory drugs and possesses proapoptotic and antitumorigenic activities. Although tolfenamic acid (TA) induces apoptosis in head and neck cancer cells, the relationship between NAG-1 and TA has not been determined. This study investigated the induction of apoptosis in head and neck cancer cells treated by TA and the role of NAG-1 expression in this induction. TA reduced head and neck cancer cell viability in a dose-dependent manner and induced apoptosis. The induced apoptosis was coincident with the expression of NAG-1. Overexpression of NAG-1 enhanced the apoptotic effect of TA, whereas suppression of NAG-1 expression by small interfering RNA attenuated TA-induced apoptosis. TA significantly inhibited tumor formation as assessed by xenograft models, and this result accompanied the induction of apoptotic cells and NAG-1 expression in tumor tissue samples. Taken together, these results demonstrate that TA induces apoptosis via NAG-1 expression in head and neck squamous cell carcinoma, providing an additional mechanistic explanation for the apoptotic activity of TA

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio