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The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.
Experiments were carried out to determine methane (CH4) consumption in different soil (vertisol) aggregates under elevated carbon dioxide (eCO2) and temperature. Soil aggregates of <0·25 mm diameter (microaggregates), 0·25–1 mm diameter (mesoaggregates) and 1–2 mm diameter (macroaggregates) were incubated under different CO2 (400, 800 and 1200 µm/m or ppm CO2) and temperature (25, 35 and 45 °C) conditions. Methane consumption was high in mesoaggregates and low in microaggregates under ambient CO2 and temperature (25 °C). However, eCO2 and temperature significantly inhibited CH4 consumption and decreased culturable microbial numbers. Methane consumption in mesoaggregates was inhibited by 21–66% at 800–1200 ppm of CO2. Principal component analysis designated soil aggregate size as the most important component of variation, followed by temperature and CO2. Ordination biplot indicated eCO2 and temperature impacted negatively on CH4 consumption and culturable methanotrophs. Results highlighted that mesoaggregates of 0·25–1·00 mm are hotspots for CH4 consumption and that rising atmospheric CO2 and temperature may inhibit CH4 consumption significantly in a tropical vertisol.
To investigate associations of maternal periconceptional shellfish, lean fish and fatty fish intake with risk of pregnancy complications.
In this prospective cohort study, we collected information on intake of seafood subtypes using FFQ. We categorized seafood intake into frequencies of <0·2 servings/month, 0·2 servings/month–<0·5 servings/week, 0·5–1·0 servings/week and >1 servings/week. We ascertained gestational hypertension, pre-eclampsia, gestational diabetes and preterm birth diagnoses from medical records. Using generalized linear models with a log link, the Poisson family and robust standard errors, we estimated risk ratios and 95 % confidence intervals across seafood intake categories.
The Omega study, a study of risk factors for pregnancy complications among women recruited from prenatal clinics in Washington State, USA, 1996–2008.
The current study included 3279 participants from the Omega study.
Median (interquartile range) shellfish, lean fish and fatty fish intake was 0·3 (0–0·9), 0·5 (0–1·0) and 0·5 (0·1–1·0) servings/week, respectively. Lean fish intake of >1 servings/week (v. <0·2 servings/month) was associated with a 1·55-fold higher risk of preterm birth (95 % CI 1·04, 2·30) and was not associated with the other pregnancy complications. Higher intake of seafood (total or other subtypes) was not associated with pregnancy complications (separately or combined).
Higher intake of lean fish, but not fatty fish or shellfish, was associated with a higher risk of preterm birth; these findings may have significance for preterm birth prevention. Studies of mechanisms and potential contributing factors (including seafood preparation and nutrient/contaminant content) are warranted.
We have carried out an ALMA Cycle 2 survey of 15 confirmed or candidate low-mass (<0.2M⊙) members of the TW Hya Association (TWA) with the goal of detecting line emission from CO molecular gas and continuum emission from cold dust. Our targets have spectral types of M4-L0 and hence represent the extreme low end of the TWA's mass function. The survey has yielded a detection of 12CO(2–1) emission around TWA 34. This newly discovered ~10 Myr-old molecular gas disk lies just ~50pc from Earth.
Low-temperature stress is an important factor affecting the growth and development of rice in temperate and high-elevation areas. In this study, 220 germplasm lines were used for screening of tolerant genotypes, validation of molecular markers and identification of robust markers for seedling-stage chilling stress tolerance to be used in marker-assisted breeding (MAS) programme. The temperature regimes imposed in the growth chamber simulated cold-stress injuries at the seedling stages of the germplasm lines. The genotypes were classified into six classes: those having susceptible genotypes were classified into moderately and highly susceptible types, while tolerant types into moderately tolerant, tolerant, highly tolerant and very highly tolerant classes. Genotypes namely Langma, Umleng-1 and Geetanjali showed survival up to 25 d, which were better than the positive check Kalinga-III surviving up to 20 d under chilling stress. Ten simple sequence repeat (SSR) markers were tested for differentiation of genotypes. Individual use of SSR markers like RM284, RM286, RM85, RM341 and RM5746 can be applied in MAS breeding including combination use of non-pair markers like RM284, RM239 and RM85, which was even better than the combined use of RM284 and RM85. However, combined use of all ten markers can most effectively be employed for cold tolerance through MAS breeding.
Aspiration pneumonia is an important cause of death in head and neck cancer patients. This study therefore aimed to evaluate the risk factors associated with aspiration pneumonia in head and neck cancer patients.
Hospital death records from 12 years (2000–2012) were reviewed to obtain the number of deaths. Treatment details and cause of death were analysed. Statistical analysis was performed to identify the risk factors for aspiration pneumonia.
The records revealed that aspiration pneumonia was the cause of death in 51 out of 85 patients. Primary tumour site (oropharynx and hypopharynx, odds ratio 3.3; 95 per cent confidence interval 1.17–9.4, p = 0.02) and advanced tumour stage (odds ratio 4.2, 95 per cent confidence interval 1.16–15.61, p = 0.02) had significant negative impacts on aspiration pneumonia related mortality.
Advanced pharyngeal cancer patients are at an increased risk of aspiration pneumonia related death. Investigations for the early detection of this condition are recommended in these high-risk patients.
Insulin-like growth factor binding protein-5 (IGFBP-5) is a key molecule in
mammary gland development, which facilitates the removal of mammary epithelial
cells (MECs) by apoptosis that takes place during remodeling of the mammary
gland during involution. IGFBP-5 binds with IGFs for their bioavailability.
IGFBP-5 has been reported to perform pleiotropic roles such as cellular
apoptosis, proliferation and differentiation. To understand the role of IGFBP-5
during lactation and clinical mastitis, expression profiling of IGFBP-5 at the
protein level was performed in both indigenous cows (Bos
indicus) and buffaloes (Bubalus bubalis) belonging to
two different breeds – Sahiwal cows and Murrah buffaloes.
Reverse-transcriptase PCR (RT-PCR) of IGFBP-5 mRNA confirmed its expression in
milk somatic cells and MECs of Sahiwal cows. ELISA was performed for
quantitative measurement of IGFBP-5 concentrations in milk during different days
(0, 50, 100, 150, 200, 250 and 300) of lactation, during the involution period
and in animals exhibiting short lactation and clinical mastitis. The highest
concentration of IGFBP-5 in milk was observed during the involution period
followed by colostrum, late and early lactation, respectively, in both cattle
and buffaloes. No significant difference in the concentration of IGFBP-5 was
observed during the first 150 days of lactation between cows and buffaloes.
However, higher concentration of IGFBP-5 was observed in cows during late
lactation (200 to 300 days) in comparison with buffaloes. To validate the ELISA
data, quantitative real-time PCR was performed in MECs of Sahiwal cows. The
relative mRNA abundance of IGFBP-5 was found to be significantly
(P<0.05) higher on day 15 than between 50 and 150
days of lactation in case of Sahiwal cows. Highest mRNA expression of IGFBP-5
was observed around 300 days of lactation followed by 200 and 250 days
(P<0.05), respectively. Murrah buffaloes showed
low levels of IGFBP-5 protein in milk as compared with Sahiwal cows during
lactation in ELISA. Animals having history of short lactation length (short
lactating animals) showed higher levels of IGFBP-5 expression (at protein level)
in comparison with normal lactating animals. We propose that higher level
IGFBP-5 expression may have functional significance in lactation persistency. As
a pro-apoptotic molecule, higher expression of IGFBP-5 was observed to be
inversely related to lactation length and milk production.
To explore the treatment outcomes of patients treated with re-irradiation for recurrent or second primary head and neck cancer.
An analysis was performed of 79 head and neck cancer patients who underwent re-irradiation for second primaries or recurrent disease from January 1999 to December 2011.
Median time from previous radiation to re-irradiation for second primary or recurrence was 53.6 months (range, 2.7–454.7 months). Median age at diagnosis of first primary was 54 years. Median re-irradiation dose was 45 Gy (range, 45–60 Gy). Acute grade 3 or worse toxicity was seen in 30 per cent of patients. Median progression-free survival for recurrent disease was 15.0 months (95 per cent confidence interval, 8.33–21.66). The following factors had a statistically significant, positive impact on progression-free survival: patient age of less than 50 years (median progression-free survival was 29.43, vs 13.9 months for those aged 50 years or older; p = 0.004) and disease-free interval of 2 years or more (median progression-free survival was 51.66, vs 13.9 months for those with less than 2 years disease-free interval).
Re-irradiation of second primaries or recurrences of head and neck cancers with moderate radiation doses yields acceptable progression-free survival and morbidity rates.
Solid state nuclear track detectors have been used for measuring axially emitted protons from a 2.2-kJ energy plasma focus device. The flux of the protons emerging out from the pinched plasma column of the plasma focus device has been found to saturate the CR-39 detectors. Aluminum filters have been used to avoid the saturation effect. By varying the aluminum filter thickness as well as the etching time of CR-39 detectors, proton tracks have been analyzed. Proton energy above 200 keV to about 1 MeV has been measured by using different thicknesses of aluminum filters. On increasing the etching hours, the most probable track diameter is found to be shifted from lower to higher values. The track number density decreases on increase of the filter thickness, whereas the track diameters increase linearly with respect to the etching time.
The manner in which young classical T Tauri stars (cTTs) and brown dwarfs accrete gas from their surrounding disks and simultaneously drive jets and outflows is central to star and planet formation and angular momentum evolution, but remains an ill-understood and hotly debated subject. One of the central concerns is the stellar field geometry: while analytic theories assume an idealized stellar dipole, T Tauri fields are observed to be complex multipolar beasts. I present an analytic generalization of the X-wind theory to include such fields. Independent of the precise field geometry, the generalized model makes a unique prediction about the relationship between various cTTs observables. I show that this prediction is supported by observations of accretion rate, hot spot size, stellar rotation and field strength from stellar to brown dwarf masses, including recent detailed spectropolarimetric measurements. I also discuss the unique insights offered by recent magnetic field measurements on accreting brown dwarfs: while they agree with the accretion theory above, they also pose a puzzle for magnetic field generation theory. Resolving this conundrum promises to illuminate our general picture of accretion and angular momentum transport in fully convective objects.
This paper examines the trends in utilization of five indicators of reproductive and child health services, namely, childhood immunization, medical assistance at delivery, antenatal care, contraceptive use and unmet need for contraception, by wealth index of the household in India and two disparate states, Uttar Pradesh and Maharashtra. The data from three rounds of the National Family and Health Survey conducted during 1992–2005 are analysed. The wealth index is computed using principal component derived weights from a set of consumer durables, land size, housing quality and water and sanitation facilities of the household, and classified into quintiles for all three rounds. Bivariate analyses, rich–poor ratio and concentration index are used to understand the trends in utilization of, and inequality in, reproductive and child health services. The results indicate huge disparities in utilization of these services, largely to the disadvantage of the poor. Utilization of basic childhood immunization among the poorest and the poor stagnated in India, as well as in both states, during 1998–2005 compared with 1992–1998. The use of maternal care services such as medical assistance at delivery and antenatal care remained at a low level among the poor over this period. However, contraceptive use increased relatively faster among the poor, even with higher unmet need. Of all these services, the inequality in medical assistance at delivery is consistently large, while that of contraceptive use is small. The state-level differences in service coverage by wealth quintiles over time are large.
The collapse of a molecular cloud core leads to the creation of a newborn star and attendant circumstellar accretion disk. The action of disk accretion during and after collapse likely controls the initial mass and angular momentum of these young stellar objects (YSOs). It also has a hand in shaping the conditions under which planetary systems are born. Determining the observational properties of YSOs, particularly their variations with environment, mass and time, can therefore place stringent constraints on the physical processes at play during both stellar and planetary formation. In this chapter, we give an overview of the current knowledge of YSO properties, with an emphasis on their implications for both processes.
Circumstellar disks are a ubiquitous outcome of the star formation process, making them a powerful probe of YSO evolution. In addition, disks are the birthsite of planetary systems and can therefore be used to constrain the overall planet formation process (via statistical analyses) and some of the key physical mechanisms, such as grain growth, vertical settling or radial migration (via detailed studies of individual objects). We focus our discussion on the analysis of young, optically thick, gas-rich protoplanetary disks. In particular, we focus on their dust component which, although it amounts to only a tiny fraction (on the order of 1%) of the total mass, represents the building blocks of planetesimals and planets. We also address some observations of more evolved debris disks.
A pseudo-Dirac neutrino of mass 50–100 GeV and mass splitting of
5 GeV can be a good candidate for dark matter. The number density
of such dark matter should be close the the baryon density in order
to get a dark matter density Ωm ~ 0.25. Production of
heavy neutrinos by electro-weak sphaleron processes can ensure that
the heavy neutrino asymmetry be of the same order as the baryon
asymmetry. A mass splitting of the order.
To improve case selection for near-total laryngectomy by identifying the causes of poor oncological and functional outcomes.
Analysis of prospectively accrued data for 28 consecutive cases of near-total laryngectomy undertaken between 1996 and 2005 at a tertiary care centre. We analysed the impact of tumour extent and location, patient physiological status, and surgical technique on disease-free survival and on functional outcome.
Patients' average four-year Kaplan–Meier disease-free survival was 74 per cent (95 per cent confidence intervals, 46–89 per cent). Eighty-two per cent of patients had good to excellent functional outcomes. Pre-operative tumour extension to the ipsilateral arytenoid significantly compromised disease-free survival (patients with this development had a two-year survival of 40 per cent; p = 0.001). Internal communicating fistula formation (i.e. a fistula between the neopharynx and myomucosal shunt lumens) occurred in five of 28 cases and was uniformly associated with a poor functional outcome (i.e. lack of phonation with or without aspiration). Fistula formation was significantly more likely in cases with tumour involving the ipsilateral arytenoid and the ipsilateral subglottis.
Significant disparity exists for the functional outcome of near-total laryngectomy in patients who develop post-surgical internal fistula, compared with those with uneventful healing. Tumour involvement of the ipsilateral arytenoid compromises the oncological and functional results. Tumour extension to the subglottis may compromise functional outcome. Near-total laryngectomy should be avoided in cases with ipsilateral arytenoid involvement, and undertaken with caution in cases with subglottic extension.
Head and neck cancer care was analysed in 2167 unselected patients for management compliance and outcome. Median age was 55 years, with a male to female ratio of 5.5[ratio ]1. Major sites were oropharynx (32.4 per cent), larynx (19.8 per cent), oral (16.6 per cent) and hypopharynx (12.9 per cent). Stage-wise distribution was I–II=8.9 per cent, III=20.6 per cent and IV=60.3 per cent and unstaged=10.2 per cent. Squamous cell carcinoma was the dominant histology for 90.9 per cent. Clinic-based cancer-directed treatment decisions were made for 1905 patients: curative intent in 53 per cent, palliative in 35 per cent and for the remaining 262 (12 per cent) supportive care. Overall, 1209 (56 per cent) patients complied with the prescribed treatments; 62 per cent, 54 per cent, and 35 per cent of curative, palliative and supportive care intent groups, respectively. Modalities were radiotherapy alone (64.6 per cent), combined surgery with irradiation (17.6 per cent), and chemoradiotherapy (11.2 per cent). Median follow-up periods were 17.5 and three months in curative and palliative groups respectively. Overall, 712 (33 per cent) cases received curative therapy, with three-year disease-specific survival of 49 per cent. Patient compliance was a major obstacle. The comparison of this series with the USA, Canada and Norway showed wide disparities in stage of presentation and survival.
Nacre, the shiny inner layer of mollusk shells is a model biomimetic nanocomposite system. Its exceptional mechanical properties have been the inspiration for materials scientists for several decades. Nacre exhibits a layered brick and mortar structure. It is composed of 95% inorganic (aragonitic CaCO3) phase and 5% organic (mainly proteins and polysaccharides) phase that are arranged in interlocked brick and mortar architecture with the mineral as bricks and organics as the mortar. In the current work, we describe the dynamic nanomechanical behavior of nacre using dynamic nanoindentation (nano-DMA) experiments. Two sets of loads were applied to obtain the dynamic response from varying depths in nacre. These tests were performed at three different frequencies (25, 50, and 100 Hz) to study the effect of frequency on the dynamic properties of nacre. The loss modulus (E″) and the loss factor (tan δ) were measured. Both of these parameters were observed to increase with increase in depth. Significant increase in tan δ was observed with the increase in frequency. Photoacoustic Fourier transform infrared spectroscopic studies on nacre indicate the presence of water in nacre. This water may be present at nanograin interfaces in nacre platelets, at organic–inorganic interfaces, and also in the organic phase in nacre. We believe that water is one of the significant contributors to the viscoelasticity of nacre. Our results indicate that the aragonite platelets in nacre may also contribute to viscoelasticity.
Nacre, the inner iridescent layer of seashells is a model biomimetic system composed of 95% of inorganic (aragonite) phase and 5% of organic phase. Nacre exhibits an interlocked layered “brick and mortar” structure where the bricks are made up of aragonitic calcium carbonate and mortar is an organic phase. Here, we report the role of indentation load and penetration depth on measurement of nanomechanical properties of nacre. A range of loads from 10 μN to 10,000 μN were applied to obtain the response from different depths of nacre. The values of hardness and elastic modulus decrease with increasing load (i.e., increase in penetration depth). The variation in these values is significant at lower loads and decreases with increase in indentation load. From our results, it appears that the nanoindentation tests done at lower loads are highly influenced by micro and nanostructure in nacre. The indentation experiments performed at low loads indicate an elastic modulus of about 15 GPa for the organic phase. The low load, low penetration experiments appear to be better indicators of nanomechanical behavior. Also, we have observed a step-like behavior in the load-displacement curves at high load indentations on nacre. These features are attributed to the organic layer between the aragonite platelets. The indentation tests with penetration depths more than ∼250-300 nm often disrupt the organic layer and the behavior is not recovered in the unloading part of the curve. The microarchitecture and the composition of nacre contribute to the decrease in hardness values with increasing depth along with the indentation size effects.
The antibiogram pattern and seasonal distribution of Salmonella serotypes were analysed retrospectively over a 6-year period from January 1999 to December 2004. Blood cultures received in the Bacteriology Laboratory were processed by standard procedures and the Salmonella spp. isolates were identified with specific antisera and standard biochemical tests. Antimicrobial susceptibility testing was carried out by a standard disc diffusion method and the minimum inhibitory concentration (MIC) of ciprofloxacin for 332 representative Salmonella isolates was determined by E test. Salmonella Typhi (75·7%) was the predominant serotype among 830 Salmonella spp. isolated during the study period followed by S. Paratyphi A (23·8%). The maximum number of enteric fever cases occurred during April–June (dry season) followed by July–September (monsoon season). There was a decrease in multidrug-resistant (MDR) S. Typhi, but MDR S. Paratyphi A isolates increased. There was also a dramatic increase in nalidixic acid-resistant isolates. All isolates were susceptible to third-generation cephalosporins and ciprofloxacin except one S. Typhi strain which demonstrated high-level ciprofloxacin resistance with a MIC of 16 μg/ml. A knowledge of the seasonal distribution and antibiotic resistance pattern of Salmonella in a particular geographical region is helpful in the delineation of appropriate control measures required for prevention of enteric fever.
Nacre, the shiny inner layer of seashells is a model biomimetic system composed of 95% of inorganic (aragonite) phase and 5% of organic phase (mainly proteins and polysaccharides). Nacre exhibits an interlocked layered “brick and mortar” structure where the bricks are made up of aragonite and mortar is the organic phase. We have performed nanoindentation and dynamic nanoindentation tests to study the nanomechanical and dynamic nanomechanical response of nacre. The indentation experiments performed at low loads indicate an elastic modulus of about 15 GPa for the organic phase. The low load, low penetration experiments appear to be better indicators of nanomechanical behavior. Dynamic nanomechanical response of nacre was studied using dynamic nanoindentation (nano-DMA). Significant increase in the values of tan δ was observed with increase in frequency. Also the dynamic nanoindentation experiments indicate that nacre exhibits viscoelastic behavior. Further, fourier transform spectroscopy experiments of nacre in innate and undisturbed state indicate the presence of water in nacre. The nanograin structure of nacre platelets, as well as the entrapped and adsorbed water, is two important contributors to the viscoelastic response of nacre. Atomic force microscopy experiments also indicate a very high force to remove organic from the aragonite in nacre. These experiments provide important insight into nanomechanical response of nacre, its constituents and also interfaces.