Estimates of air–sea feedbacks on sea surface temperature anomalies in the southern ocean

Sea surface temperature (SST) air–sea feedback strengths and associated decay time scales in the Southern Ocean (SO) are estimated from observations and reanalysis datasets of SST, air–sea heat fluxes, and ocean mixed layer depths. The spatial, seasonal, and scale dependence of the air–sea heat flux feedbacks is mapped in circumpolar bands and implications for SST persistence times are explored. It is found that the damping effect of turbulent heat fluxes dominates over that due to radiative heat fluxes. The turbulent heat flux feedback acts to damp SSTs in all bands and spatial scales and in all seasons, at rates varying between 5 and 25 W m⁻² K⁻¹, while the radiative heat flux feedback has a more uniform spatial distribution with a magnitude rarely exceeding 5 W m⁻² K⁻¹. In particular, the implied net air–sea feedback (turbulent + radiative) on SST south of the polar front, and in the region of seasonal sea ice, is as weak as 5–10 W m⁻² K⁻¹ in the summertime on large spatial scales. Air–sea interaction alone thus allows SST signals induced around Antarctica in the summertime to persist for several seasons. The damping effect of mixed layer entrainment on SST anomalies averages to approximately 20 W m⁻² K⁻¹ across the ACC bands in the summer-to-winter entraining season and thereby reduces summertime SST persistence to less than half of that predicted by air–sea interaction alone (i.e., 3–6 months).National Science Foundation (U.S.). Frontiers in Earth System Dynamic

Connection between sea surface anomalies and atmospheric quasi-stationary waves

Large scale, quasi-stationary atmospheric waves (QSWs) are known to be strongly connected with extreme events and general weather conditions. Yet, despite their importance, there is still a lack of understanding about what drives variability in QSW. This study is a step towards this goal, and identifies three statistically significant connections between QSWs and sea surface anomalies (temperature and ice cover) by applying a maximum covariance analysis technique to reanalysis data (1979-2015). The two most dominant connections are linked to the El Ni\~no Southern Oscillation and the North Atlantic Oscillation. They confirm the expected relationship between QSWs and anomalous surface conditions in the tropical Pacific and the North Atlantic, but they cannot be used to infer a driving mechanism or predictability from the sea surface temperature or the sea ice cover to the QSW. The third connection, in contrast, occurs between late winter to early spring Atlantic sea ice concentrations and anomalous QSW patterns in the following late summer to early autumn. This new finding offers a pathway for possible long term predictability of late summer QSW occurrence

Autoimmune hepatitis in India: profile of an uncommon disease

BACKGROUND: Autoimmune hepatitis (AIH) has been reported to show considerable geographical variation in frequency and clinical manifestations. It is considered a rare cause of liver disease in India. The present study was undertaken to determine the incidence, clinical, biochemical and histological profile of AIH in this part of the world. METHODS: Patients presenting with acute or chronic liver disease between January 1999 and June 2002 were evaluated prospectively. AIH was diagnosed using the international autoimmune hepatitis group criteria. Workup included clinical, biochemical, USG, viral markers, UGI endoscopy, AI markers (ANA, SMA, Anti-LKM, AMA, RF, p-ANCA) using indirect immunofluorescence and liver biopsy if possible. RESULTS: Forty-one of 2401 (1.70%) patients were diagnosed to have autoimmune liver disease. Out of these, 38 had autoimmune hepatitis and the rest 3 had primary biliary cirrhosis. The mean age of the patients of autoimmune hepatitis was 36.2 (15.9) years, 34 (89.4%) were females, and the duration of symptoms was 20.3 (20.5) months. Nineteen (50%) of them presented with chronic hepatitis, 13 (34.2%) as cirrhosis, 5 (13.1%) with acute hepatitis and 1 (2.6%) with cholestatic hepatitis. The presentations were jaundice in 21 (55.2%), pedal edema and hepatomegaly in 17 (44.7%), splenomegaly in 13 (34.2%), encephalopathy, abdominal pain in 9 (23.6%) and fever in 8 (21%). Twelve had esophageal varices and 3 had bled. Biochemical parameters were ALT 187 (360) U/L, AST 157 (193) U/L, ALP 246 (254) U/L, globulin 4.1 (1.6) g/dL, albumin 2.8 (0.9) g/dL, bilirubin 5.2 (7.4) mg/dL, prothrombin time 17 (7) sec and ESR 47 (17) sec. The autoimmune markers were SMA (24), ANA (15), both SMA and ANA (4), AMA (1), rheumatoid factor (2), pANCA (1), and Anti-LKM in none. Thirty (79%) patients had definite AIH and eight (21%) had probable AI hepatitis. Associated autoimmune diseases was seen in 15/38 (39.4%), diabetes 4, hypothyroidism 3, vitiligo 2, thrombocytopenia 2, rheumatoid arthritis 2, Sjogren's syndrome 1 and autoimmune polyglandular syndrome III in 1. Viral markers were positive in two patients, one presenting as acute hepatitis and HEV-IgM positive and another anti-HCV positive. CONCLUSION: In India, autoimmune hepatitis is uncommon and usually presents with chronic hepatitis or cirrhosis, acute hepatitis being less common. Age at presentation was earlier but clinical parameters and associated autoimmune diseases were similar to that reported from the west. Primary biliary cirrhosis is rare. Type II AIH was not observed

Constraints on alternative models to dark energy

The recent observations of type Ia supernovae strongly support that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friemann equation. We consider a general modified Friedmann equation. Three different models are analyzed in detail. The current supernovae data and the Wilkinson microwave anisotropy probe data are used to constrain these models. A detailed analysis of the transition from the deceleration phase to the acceleration phase is also performed.Comment: 10 pages, 1 figure, revtex

Design of a robotic hand with a biologically-inspired parallel actuation system for prosthetic applications

Trabajo presentado al 34th Annual Mechanisms and Robotics Conference celebrado en Quebec del 15 al 18 de agosto de 2010.This paper presents the design of a robotic hand for prosthetic applications. The main characteristic of this robotic hand is its biologically-inspired parallel actuation system, which is based on the behavior/strength space of the Flexor Digitorum Profundus (FDP) and the Flexor Digitorum Superficialis (FDS) muscles. The design separates the strength space of the FDS and FDP muscles into a lighter strength region where finer manipulation and general approach tasks are executed, and a higher strength region where the more robust grasps are achieved. Two parallel actuator types and kinematic structures are designed to complement the requirements of both strength space regions.This research was performed under an award/contract from Telemedicine Advanced Technology Research Center (TATRC), of the U.S. Army Medical Research and Materiel Command (USAMRMC) of the U.S. Department of Defense.Peer Reviewe

Development and initial validation of a computer-administered health literacy assessment in Spanish and English: FLIGHT/VIDAS.

Current measures of health literacy have been criticized on a number of grounds, including use of a limited range of content, development on small and atypical patient groups, and poor psychometric characteristics. In this paper, we report the development and preliminary validation of a new computer-administered and -scored health literacy measure addressing these limitations. Items in the measure reflect a wide range of content related to health promotion and maintenance as well as care for diseases. The development process has focused on creating a measure that will be useful in both Spanish and English, while not requiring substantial time for clinician training and individual administration and scoring. The items incorporate several formats, including questions based on brief videos, which allow for the assessment of listening comprehension and the skills related to obtaining information on the Internet. In this paper, we report the interim analyses detailing the initial development and pilot testing of the items (phase 1 of the project) in groups of Spanish and English speakers. We then describe phase 2, which included a second round of testing of the items, in new groups of Spanish and English speakers, and evaluation of the new measure\u27s reliability and validity in relation to other measures. Data are presented that show that four scales (general health literacy, numeracy, conceptual knowledge, and listening comprehension), developed through a process of item and factor analyses, have significant relations to existing measures of health literacy

Effect of synthesis conditions on formation pathways of metal organic framework (MOF-5) Crystals

Metal Organic Frameworks (MOFs) represent a class of nanoporous crystalline materials with far reaching potential in gas storage, catalysis, and medical devices. We investigated the effects of synthesis process parameters on production of MOF-5 from terephthalic acid and zinc nitrate in diethylformamide. Under favorable synthesis conditions, we systematically mapped a solid formation diagram in terms of time and temperature for both stirred and unstirred conditions. The synthesis of MOF-5 has been previously reported as a straightforward reaction progressing from precursor compounds in solution directly to the final MOF-5 solid phase product. However, we show that the solid phase formation process is far more complex, invariably transferring through metastable intermediate crystalline phases before the final MOF-5 phase is reached, providing new insights into the formation pathways of MOFs. We also identify process parameters suitable for scale-up and continuous manufacturing of high purity MOF-5

An analysis of age, technology usage, and cognitive characteristics within information retrieval tasks

This work presents two studies that aim to discover whether age can be used as a suitable metric for distinguishing performance between individuals or if other factors can provide greater insight. Information retrieval tasks are used to test the performance of these factors. First, a study is introduced that examines the effect that fluid intelligence and Internet usage has on individuals. Second, a larger study is reported on that examines a collection of Internet and cognitive factors in order to determine to what extent each of these metrics can account for disorientation in users. This work adds to growing evidence showing that age is not a suitable metric to distinguish between individuals within the field of human-computer interaction. It shows that factors such as previous Internet experience and fluid-based cognitive abilities can be used to gain better insight into users' reported browsing experience during information retrieval tasks

Influence of Fe Addition on the Martensitic Transformation, Structure and Magnetic Properties of Metamagnetic Ni-Co-Mn-Sn Alloys

In this study the effect of Fe for Ni substitution in Ni44Co6Mn39Sn11 metamagnetic shape memory alloys on their structure, magneto-structural transformation characteristics, magnetic and magnetocaloric properties was studied. The results show that the structure and martensite transformation behavior strongly depends on the Fe concentration. The martensitic transformation temperature decreases with 1 at.% of Fe and is suppressed with higher Fe content. It was further found that substitution of Fe for Ni leads to lowering of the value of magnetic entropy change

Dilatonic ghost condensate as dark energy

We explore a dark energy model with a ghost scalar field in the context of the runaway dilaton scenario in low-energy effective string theory. We address the problem of vacuum stability by implementing higher-order derivative terms and show that a cosmologically viable model of ``phantomized'' dark energy can be constructed without violating the stability of quantum fluctuations. We also analytically derive the condition under which cosmological scaling solutions exist starting from a general Lagrangian including the phantom type scalar field. We apply this method to the case where the dilaton is coupled to non-relativistic dark matter and find that the system tends to become quantum mechanically unstable when a constant coupling is always present. Nevertheless, it is possible to obtain a viable cosmological solution in which the energy density of the dilaton eventually approaches the present value of dark energy provided that the coupling rapidly grows during the transition to the scalar field dominated era.Comment: 26 pages, 6 figure