Heterodyne performance and characteristics of terahertz MgB2hot electron bolometers

We have studied THz heterodyne detection in sub-micrometer MgB2 hot electron bolometer (HEB) mixers based on superconducting MgB2 films of ∼5nm (HEB-A), corresponding to a critical temperature (Tc) of 33.9 K, and ∼7nm (HEB-B), corresponding to a \u1d447\u1d450 of 38.4 K. We have measured a double sideband (DSB) receiver noise temperature of 2590 K for HEB-A and 2160 K for HEB-B at 1.6 THz and 5 K. By correcting for optical losses, both HEBs show receiver noise temperatures of ∼1600 K referenced to the front of anti-reflection (AR)-coated Si lenses. An intermediate frequency (IF) noise bandwidth of 11 GHz has been measured for both devices. The required local oscillator (LO) power is about 13 μW for both HEBs. We have also measured a DSB receiver noise temperature of 3290 K at 2.5 THz and 5 K but with an AR-coated lens optimized for 1.6 THz. Besides, we have observed a step-like structure in current voltage (IV) curves, which becomes weaker when the LO power increases and observable only in their differential resistance. Such a correlated structure appears also in the receiver output power as a function of voltage, which is likely due to electronic inhomogeneities intrinsic to the variations in the thickness of the MgB2 films. Different behavior in the IV curves around the low bias voltages, pumped with the same LO power at 1.6 and 5.3 THz, was observed for HEB-B, suggesting the presence of a high-energy σ-gap in the MgB2 film

Short-Term Soil Organic Matter and Carbon Responses to Contrasting Grazing Intensities in Integrated Crop-Livestock Systems

Combining integrated crop-livestock systems under no-till management may improve soil organic matter (SOM) build up and improve soil C sequestration. Grazing cover crops appears as a possibility to combine crops and livestock in a farm system. Further SOM and soil C increase can be achieved by adding perennial grasses into crop rotations. However, the effect of grazing intensity in such systems are not fully understood. This 2-yr study investigated short-term effects of cropping system [winter cover crops-summer cotton (Gossypium hirsutum L.) and winter cover crops-summer bahiagrass (Paspalum notatum Flüggé) rotations], grazing intensity (no grazing, heavy, moderate, and light grazing), and N fertilization (34 and 90 kg N ha-1 ), on OM and soil C of the soil-surface (0-15 cm) and deep-soil (0-90 cm) under no-till. Preliminary results indicate that treatments containing bahiagrass improved SOM in 1.5 g kg-1 compared to winter grazing on cover crops-cotton systems (P = 0.017). There were no differences among treatments for soil total C stock (15.4 Mg ha-1) and particulate OM-C (4.8 Mg ha-1) at the 15-cm depth (P \u3e 0.1). Carbon concentration increased from 8.0 to 12.6 g kg-1 as aggregate fraction decreased from 250 – 2000 to \u3c 53 µm (P \u3c 0.001). Nonetheless, C stock was not affected by aggregate fraction, with each fraction containing 3.8 Mg C ha-1, on average. Carbon stocks from 0-15, 15-30, 30-60, and 60-90-cm depths did not differ among treatments (P = 0.743), totalizing 30.4 Mg C ha-1 in the soil profile. Long-term studies are necessary to better understand the role of cropping system and grazing intensities on soil OM and C responses on surface and deep soil

Geo-environmental mapping using physiographic analysis: constraints on the evaluation of land instability and groundwater pollution hazards in the Metropolitan District of Campinas, Brazil

Geo-environmental terrain assessments and territorial zoning are useful tools for the formulation and implementation of environmental management instruments (including policy-making, planning, and enforcement of statutory regulations). They usually involve a set of procedures and techniques for delimitation, characterisation and classification of terrain units. However, terrain assessments and zoning exercises are often costly and time-consuming, particularly when encompassing large areas, which in many cases prevent local agencies in developing countries from properly benefiting from such assessments. In the present paper, a low-cost technique based on the analysis of texture of satellite imagery was used for delimitation of terrain units. The delimited units were further analysed in two test areas situated in Southeast Brazil to provide estimates of land instability and the vulnerability of groundwater to pollution hazards. The implementation incorporated procedures for inferring the influences and potential implications of tectonic fractures and other discontinuities on ground behaviour and local groundwater flow. Terrain attributes such as degree of fracturing, bedrock lithology and weathered materials were explored as indicators of ground properties. The paper also discusses constraints on- and limitations of- the approaches taken

Morpho/Proteomic Comparative between High Grade Pleomorphic Sarcoma and Metastasis Diagnosed in an Old Captive Common Hippo

Old age is a risk factor for cancer development in humans and animals, and studies have shown that tumors in animals are acceptable models for studying human cancers, considering the similarities between their factors. This work was conducted in a 53-year-old captive female common hippo (Hippopotamus amphibious) with a left leg tumor and metastatic mass. Histopathological and immunohistochemical analyses were carried out with a final diagnosis of a high grade pleomorphic sarcoma. A proteomic study using mass spectrometry was added in order to identify further aspects of the primary tumor and metastasis which could improve our understanding, and each tissue showed a proteomic profile indicative of its pathologic state with significant differences between healthy tissue, primary and metastatic tumors. Low levels of beta-actin in primary tumors were identified, and this may be associated with a possible consequence of cytoskeleton dynamic modification. In metastatic tissue, these dynamics may be affected by the presence of HSP chaperone 60.FAPESP: 2012/02514-9Univ Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, BR-04039032 Diadema, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, BR-04023062 Sao Paulo, SP, BrazilAC Camargo Canc Ctr, Dept Patol, BR-01509010 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, BR-04039032 Diadema, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, BR-04023062 Sao Paulo, SP, BrazilWeb of Scienc

Dark energy, non-minimal couplings and the origin of cosmic magnetic fields

In this work we consider the most general electromagnetic theory in curved space-time leading to linear second order differential equations, including non-minimal couplings to the space-time curvature. We assume the presence of a temporal electromagnetic background whose energy density plays the role of dark energy, as has been recently suggested. Imposing the consistency of the theory in the weak-field limit, we show that it reduces to standard electromagnetism in the presence of an effective electromagnetic current which is generated by the momentum density of the matter/energy distribution, even for neutral sources. This implies that in the presence of dark energy, the motion of large-scale structures generates magnetic fields. Estimates of the present amplitude of the generated seed fields for typical spiral galaxies could reach $10^{-9}$ G without any amplification. In the case of compact rotating objects, the theory predicts their magnetic moments to be related to their angular momenta in the way suggested by the so called Schuster-Blackett conjecture.Comment: 5 pages, no figure

Prediction of intensive care admission and hospital mortality in COVID-19 patients using demographics and baseline laboratory data

Introduction: Optimized allocation of medical resources to patients with COVID-19 has been a critical concern since the onset of the pandemic. Methods: In this retrospective cohort study, the authors used data from a Brazilian tertiary university hospital to explore predictors of Intensive Care Unit (ICU) admission and hospital mortality in patients admitted for COVID-19. Our primary aim was to create and validate prediction scores for use in hospitals and emergency departments to aid clinical decisions and resource allocation. Results: The study cohort included 3,022 participants, of whom 2,485 were admitted to the ICU; 1968 survived, and 1054 died in the hospital. From the complete cohort, 1,496 patients were randomly assigned to the derivation sample and 1,526 to the validation sample. The final scores included age, comorbidities, and baseline laboratory data. The areas under the receiver operating characteristic curves were very similar for the derivation and validation samples. Scores for ICU admission had a 75% accuracy in the validation sample, whereas scores for death had a 77% accuracy in the validation sample. The authors found that including baseline flu-like symptoms in the scores added no significant benefit to their accuracy. Furthermore, our scores were more accurate than the previously published NEWS-2 and 4C Mortality Scores. Discussion and conclusions: The authors developed and validated prognostic scores that use readily available clinical and laboratory information to predict ICU admission and mortality in COVID-19. These scores can become valuable tools to support clinical decisions and improve the allocation of limited health resources

Participation of 5-HT and AT 1 Receptors within the Rostral Ventrolateral Medulla in the Maintenance of Hypertension in the Goldblatt 1 Kidney-1 Clip Model

The hypothesis that changes in neurotransmission within the rostral ventrolateral medulla (RVLM) are important to maintain the high blood pressure (BP) was tested in Goldblatt one kidney-one clip hypertension model (1K-1C). Male Wistar rats were anesthetized (urethane 1.2 g/kg, i.v.), and the effects of bilateral microinjections into the RVLM of the following drugs were measured in 1K-1C or control groups: glutamate (0.1 mol/L, 100 nL) and its antagonist kynurenic acid (0.02 mol/L, 100 nL), the angiotensin AT 1 receptor antagonist candesartan (0.01 mol/L, 100 nL), and the nonselective 5-HT receptor antagonist methiothepin (0.06 mol/L, 100 nL). Experiments in 1K-1C rats were performed 6 weeks after surgery. In anesthetized rats glutamate response was larger in hypertensive than in normotensive rats (H: Δ67 ± 6.5; N: Δ43 ± 3.54 mmHg). In contrast, kynurenic acid microinjection into the RVLM did not cause any change in BP in either group. The blockade of either AT 1 or 5-HT receptors within the RVLM decreased BP only in 1K-1C rats. A largest depressor response was caused by 5-HT receptor blockade. The data suggest that 5-HT and AT 1 receptors act tonically to drive RVLM in 1K-1C rats, and these actions within RVLM contribute to the pathogenesis of this model of hypertension

39 THz spatial filter based on a back-to-back Si-lens system

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