Birds employ rapid pitch-up motions close to the ground for different purposes: perching birds use this motion to decelerate and come to a complete stop while hunting birds, such as bald eagles, employ it to catch prey and swiftly fly away. Motivated by these observations, our study investigates how natural flyers accomplish diverse flying objectives by rapidly pitching their wings while decelerating near ground. We conducted experimental and analytical investigations focusing on rapidly pitching plates during deceleration in close proximity to the ground to explore the impact of ground proximity on the unsteady dynamics. Initially, we executed synchronous pitch-up motion, where both pitching and deceleration have the same motion duration, at different ground heights. Experimental results demonstrate that as the pitching wing approaches the ground, the instantaneous lift increases by approximately $38\,\%$ compared with a far-from-ground case, while the initial peak drag force remains relatively unchanged. Our analytical model conforms to this trend, predicting an increase in lift force as the wing approaches the ground, indicating enhanced added mass and circulatory lift force due to the ground effect. Next, we examined asynchronous pitch-up motion cases, where rapid pitching motions were initiated at different stages of deceleration. The results reveal that initiating the wing pitch early in the deceleration leads to the formation of larger counter-rotating vortices at the early stage of the manoeuvre. These vortices generate stronger dipole jets that orient backward in the later stages of the manoeuvre after impinging with the ground surface, which hunting birds utilize to accelerate after catching prey. Conversely, when the wing pitch is delayed, smaller vortices form, but their growth is postponed until late in the manoeuvre. This delayed vortex growth produces lift and drag force at the end phase of the manoeuvre that facilitates a smooth landing or perching. Thus, through strategic tuning of a rapid pitch-up motion with deceleration, natural flyers, such as birds, achieve diverse flying objectives.

While SrTiO3 exhibits promising electronic transport properties, its high thermal conductivity (κ) is detrimental for its use as a thermoelectric material. Here, we investigate the influence of oxygen non-stoichiometry on κ in bulk SrTiO3 ceramics. A significant reduction in κ was achieved in oxygen deficient SrTiO3−δ, owing to the presence of oxygen vacancies that act as phonon scattering centers. Upon oxidation of SrTiO3−δ, the κ of pristine SrTiO3 was recovered, suggesting that oxygen vacancies were indeed responsible for the reduction in κ. Raman spectroscopy was used as an independent tool to confirm the reduction of oxygen vacancies in SrTiO3−δ upon oxidation.

We review the materials paradigm for metal amorphous nanocomposite (MANC) soft magnetic materials to showcase in solid state transformers (SSTs). We report 2D finite element analysis (FEA) of 3-phase SSTs operating at 50 Hz–10 kHz frequencies. We benchmark materials in designs to control high frequency losses and achieve higher power densities. FEA models are solved in the time domain for line frequencies of 50 Hz–10 kHz and 100 KW output power for the first 4 cycles. Transformer topologies are coupled to a power analysis using a Steinmetz parameterization of magnetic losses capturing induction and field scaling for transformer grade Si steel as compared to Metglas, Ferrite, FINEMET, Co- and FeNi-based MANCs. Recently discovered FeNi-based MANCs allow smaller transformers at equivalent power as compared to Si steel, Metglas, and Co-based MANCs. Fe-rich and non-Co containing MANCs also offer economies based on lower raw materials costs compared with Co-based MANCs.

This article describes unexplored details of the intriguing spectral manifestation of the small-amplitude waves at the surfaces of a bubble-laden drop. Its natural frequencies of interfacial pulsation reveal a non-trivial variation with the position of the cavity inside the liquid. This configurational dependence of spectra is calculated for arbitrary location of the void by using a novel approach under low capillary number and low Bond number limits. The analysis is based on expansion in two sets of basis functions where their mutual transformations are utilized to enforce interfacial boundary conditions. The obtained results quantify a few important features which have both scientific and technological significance. For a concentric geometry, the inherent azimuthal degeneracy makes the frequencies for a number of vibrational modes exactly the same. For an eccentric position of the bubble, however, this degeneracy disappears, creating small deviations in the spectral values corresponding to different azimuthal modes. Such behaviour is akin to fine-structure split in an atomic system, where different quantum numbers ensure small deviation in energy levels of the states. The formulated mathematical procedure can determine the individual frequency values for the interfacial oscillation even if these are grouped closely together in bands. The paper shows how the number of fine structures inside a band and their specific values can be exploited to predict the size and position of the cavity in an opaque drop without any direct visualization of its interior.

This article describes an unexplored transport phenomenon where a mildly viscoelastic medium encroaches a narrow capillary channel under the action of surface-tension force. The ultimate goal of the study is to provide the penetration length and the intrusion rate of the liquid as functions of time. The resulting analysis would be instrumental in building an inexpensive and convenient rheometric device which can measure the temporal scale for viscoelastic relaxation from the stored data of the aforementioned quantities. The key step in the formulation is a transient eigenfunction expansion of the instantaneous velocity profile. The time-dependent amplitude of the expansion as well as the intruded length are governed by a system of integro-differential relations which are derived by exploiting the mass and momentum conservation principles. The obtained integro-differential equations are simultaneously solved by using a fourth-order Runge–Kutta method assuming a start-up problem from rest. The resulting numerical solution properly represents the predominantly one-dimensional flow which gradually slows down after an initial acceleration and subsequent oscillation. The computational findings are independently verified by two separate perturbation theories. The first of these is based on a Weissenberg number expansion revealing the departure in the unsteady imbibition due to small but finite viscoelasticity. In contrast, the second one explains the long-time behaviour of the system by analytically predicting the decay features of the dynamics. These asymptotic results unequivocally corroborate the simulation inferring the accuracy of the numerics as well as the utility of the simplified mathematical models.

The Gor Garung group of glaciers constitute an ice cover of over 4 km2 in a basin of 27 km2 area, lying in the Sutlej River catchment of the north–western Himalaya. This paper, the first record of these glaciers, their moraines and lakes observed in this area, is the result of mapping the glaciers and the pro–glacial field.

An attempt has been made to utilize lichenometry for establishing relative antiquity of various terminal moraine ridges generated by these glaciers, and six groups have been determined.

Naturally occurring sulforaphane (SF) has been extensively studied for cancer prevention. However, little is known as to which organs may be most affected by this agent, which impedes its further development. In the present study, SF was administered to rats orally either in a single dose or once daily for 7 d. Tissue distribution of SF was measured by a HPLC-based method. Glutathione S-transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), two well-known cytoprotective phase 2 enzymes, were measured using biochemical assays to assess tissue response to SF. SF was delivered to different organs in vastly different concentrations. Tissue uptake of SF was the greatest in the stomach, declining rapidly in the descending gastro-intestinal tract. SF was rapidly eliminated through urinary excretion, and urinary concentrations of SF equivalents were 2–4 orders of magnitude higher than those of plasma. Indeed, tissue uptake level of SF in the bladder was second only to that in the stomach. Tissue levels of SF in the colon, prostate and several other organs were very low, compared to those in the bladder and stomach. Moreover, induction levels of GST and NQO1 varied by 3- to 6-fold among the organs of SF-treated rats, though not strictly correlated with tissue exposure to SF. Thus, there is profound organ specificity in tissue exposure and response to dietary SF, suggesting that the potential chemopreventive benefit of dietary SF may differ significantly among organs. These findings may provide a basis for prioritising organs for further chemopreventive study of SF.

Prior to 2009 dengue fever had not been reported in the Andaman and Nicobar archipelago. In 2009, a few patients with dengue fever-like illness were reported, some of whom tested positive for dengue antibodies. In 2010, 516 suspected cases were reported, including some with dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS); 80 (15·5%) were positive for dengue antibodies. DENV RNA was detected in five patients and PCR-based typing showed that three of these belonged to serotype 1 and two to serotype 2. This was confirmed by sequence typing. Two clones of dengue virus, one belonging to serotype 1 and the other to serotype 2 appeared to be circulating in Andaman. Emergence of severe diseases such as DHF and DSS might be due to recent introduction of a more virulent strain or because of the enhancing effect of sub-neutralizing levels of antibodies developed due to prior infections. There is a need to revise the vector-borne disease surveillance system in the islands.

In this paper, we report on the growth and fabrication of thin film Si photovoltaic devices on photonic structures which were fabricated on steel and PEN and Kapton substrates. Both amorphous Si and thin film nanocrystalline Si devices were fabricated. The 2 dimensional photonic reflector structures were designed using a scattering matrix theory and consisted of appropriately designed holes/pillars which were imprinted into a polymer layer coated onto PEN, Kapton and stainless steel substrates. The photonic structures were coated with a thin layer of Ag and ZnO. Both single junction and tandem junction (amorphous/amorphous and amorphous/nanocrystalline) cells were fabricated on the photonic layers. It was observed that the greatest increase in short circuit current and efficiency in these cells due to the use of photonic reflectors was in nanocrystalline Si cells, where an increase in current approaching 30% (compared to devices fabricated on flat substrates) was obtained for thin (∼ 1 micrometer thick i layers) films of nano Si deposited on steel structures. The photonic structures (which were nanoimprinted into a polymer) were shown to stand up to temperatures as large as 300 C, thereby making such structures practical when a steel (or glass) of kapton substrate is used. Detailed measurements and discussion of quantum efficiency and device performance for various photonic back reflector structures on steel, kapton and PEN substrates will be presented in the paper.

ZnSe nanorods are grown by varying the amount of reducing agent Sodium borohydride and keeping the amount of zinc chloride, selenium powder constant. The samples are characterized using electron diffraction techniques. Simultaneously optical absorption, photoluminescence and longtime photorelaxation of these samples are studied at room temperature. An increase in band gap is observed in each case as compared to bulk ZnSe. Also the formation of nanorods is found to be favourable at particular ratio of reducing agent. An attempt is made to explain the growth and correlate the structural, optical and electrical properties.

We report here the pathological effects of a microsporidian isolate (Nosema sp.) from the lepidopteran teak defoliator Hyblaea puera Cramer. The spores were ovo-cylindrical and had a mean size of 5.1 × 2.8 μm. The midgut and fat body were the primary organs infected by the microsporidium. Subsequently, infection was observed in Malphigian tubules, tracheal epithelium and gonads. The sequence of infection observed was: midgut – fat body – tracheal membrane – Malpighian tubule – gonad. Infection of this microsporidium produced a marked negative effect on the growth and development of larvae. The weight of healthy larvae increased about 22 times from the 3rd instar to pupation while the increase was about 12 times in the infected larvae. Rearing experiments conducted in the laboratory revealed a high potential for horizontal transmission (>90%) of the microsporidium among the defoliator larvae developing together. A nearly equal degree of vertical transmission (88.7%) was also observed from the infected females to the progeny larvae. The observations reported here indicate the prospect of the microsporidium as a bio-control agent against the defoliator pest if exploited properly. Small subunit rRNA gene sequence analysis revealed that this microsporidium differed from Nosema bombycis of silk moth by only two nucleotides. The teak moth and the silk moth are not as closely related as these two parasites appear to be, implying the likelihood of host switching.

Faecal specimens of diarrhoea cases (n=2495, collected between November 2007 and October 2009) from Infectious Diseases and Beliaghata General (ID&BG) Hospital, Kolkata, India, were screened by RT–PCR using specific primers targeting region C of the capsid gene of noroviruses (NoVs) to determine the seasonal distribution and clinical characteristics of NoVs associated with diarrhoea. NoV infection was detected in 78 cases, mostly in children aged <2 years. In 22/78 positive cases, the virus was detected as the sole agent; others were as mixed infections with other enteric pathogens. Sequencing of NVGII strains showed clustering with GII.4 NoVs followed by GII.13 and GII.6 NoVs. Clinical characteristics of the diarrhoeic children and adults in Kolkata indicated that NoV infections were detected throughout the year and were associated with a mild degree of dehydration.

Recent technological advances including brain imaging (higher resolution in space andtime), miniaturization of integrated circuits (nanotechnologies), and acceleration ofcomputation speed (Moore’s Law), combined with interpenetration between neuroscience,mathematics, and physics have led to the development of more biologically plausiblecomputational models and novel therapeutic strategies. Today, mathematical models ofirreversible medical conditions such as Parkinson’s disease (PD) are developed andparameterised based on clinical data. How do these evolutions have a bearing on deep brainstimulation (DBS) of patients with PD? We review how the idea of DBS, a standardtherapeutic strategy used to attenuate neurological symptoms (motor, psychiatric), hasemerged from past experimental and clinical observations, and present how, over the lastdecade, computational models based on different approaches (phase oscillator models,spiking neuron network models, population-based models) have started to shed light ontoDBS mechanisms. Finally, we explore a new mathematical modelling approach based on neuralfield equations to optimize mechanisms of brain stimulation and achieve finer control oftargeted neuronal populations. We conclude that neuroscience and mathematics are crucialpartners in exploring brain stimulation and this partnership should also include otherdomains such as signal processing, control theory and ethics.