scholarly journals Southern Hemisphere Winter Extratropical Cyclone Characteristics and Vertical Organization Observed with the ERA-40 Data in 1979–2001

2007 ◽  
Vol 20 (11) ◽  
pp. 2675-2690 ◽  
Author(s):  
Eun-Pa Lim ◽  
Ian Simmonds

Abstract The mean characteristics and trends of Southern Hemisphere (SH) winter extratropical cyclones occurring at six levels of the troposphere over the period 1979–2001 have been investigated using the 40-yr ECMWF Re-Analysis (ERA-40) data. Cyclonic systems were identified with the Melbourne University cyclone finding and tracking scheme. This study shows that mean sea level pressure (MSLP) cyclones are more numerous, more intense, smaller, deeper, and slower moving than higher-level cyclones. The novel vertical tracing scheme devised for this research revealed that about 52% of SH winter MSLP cyclones have a vertically well organized structure, extending through to the 500-hPa level. About 80% of these vertically coherent SH cyclones keep their westward tilt until the surface cyclones reach their maximum depths, and the mean distance is 300 km between the surface and the 500-hPa level cyclone centers when the surface cyclones obtain their maturity. According to the authors’ definition of vertical organization, explosively developing cyclones are vertically very well organized systems, whose surface development is antecedent to their 500-hPa level counterpart. Over 1979–2001 cyclones have increased in their system density, intensity, and translational velocity but decreased in their scale at almost all levels. However, some of the trends are not statistically significant. The proportion of vertically well organized systems in the entire population of SH winter extratropical cyclones has considerably increased over the last 23 yr, and the mean distance between the surface and the 500-hPa- level cyclone centers has decreased. Such changes in vertical organization of extratropical cyclones are statistically significant at the 95% confidence level.

2007 ◽  
Vol 64 (9) ◽  
pp. 3328-3339 ◽  
Author(s):  
Francis Codron

Abstract In a zonally symmetric climatology with a single eddy-driven jet, such as prevails in the Southern Hemisphere summer, the midlatitude variability is dominated by fluctuations of the jet around its mean position, as described by the Southern Hemisphere annular mode (SAM). To study whether this result holds for a zonally asymmetric climatology, the observed variability of the Southern Hemisphere winter is analyzed. The mean state in this case is characterized by relatively weak stationary waves; yet there exist significant zonal variations in the mean strength and meridional structure of the subtropical jet stream. As in summer, the winter SAM signature is annular in shape and the corresponding wind anomalies are dipolar; but it is associated with two different behaviors of the eddy-driven jet in different longitudinal ranges. Over the Indian Ocean, the SAM is associated primarily with a latitudinal shift of the jet around its mean position. Over the Pacific sector, it is instead characterized by a seesaw in the wind speed between two distinct latitudes, corresponding to the positions of the midlatitude and subtropical jets. Composites of eddy forcing and baroclinicity over both sectors appear consistent with the two different behaviors. As in the zonal-mean case, high-frequency eddies both force and maintain the low-frequency wind anomalies associated with the SAM. The positive feedback by eddies is, however, not local: changes in the eddy forcing are influenced most strongly by zonal wind anomalies located upstream.


1978 ◽  
Vol 1 (16) ◽  
pp. 30 ◽  
Author(s):  
D.H. Peregrine ◽  
I.A. Svendsen

On gently sloping beaches, almost all water waves break. After the initial breaking the water motion usually appears quite chaotic. However, for a moderate time, for example two or three times the descent time of the "plunge" in a plunging breaker, the flow can be relatively well organised despite the superficial view which is largely of spray and bubbles. If waves continue to break the breaking motion, or "white water" soon becomes fully turbulent and the mean motions become quasisteady. A reasonable definition of a quasi-steady wave is one which changes little during the time a water particle takes to pass through it. We exclude water particles which may become trapped in a surface roller and surf along with the wave. At this stage in its development a wave on a beach may be described as a spilling breaker or as a bore. In fact, there is a range of these waves from those with a little white water at the crest to examples where the whole front of the wave is fully turbulent. In investigating the properties of such waves it is desirable to start by looking at the whole range of related motions. The most obvious extension is to the hydraulic jump; since, in the simplest view, it is equivalent to a bore but in a frame of reference moving with the wave. It is also an example where the mean flow is steady rather than quasisteady.


2017 ◽  
Vol 30 (13) ◽  
pp. 4915-4935 ◽  
Author(s):  
Edmund K. M. Chang

Extratropical cyclones are responsible for much of the extreme weather in the midlatitudes; thus, how these cyclones may change under increasing greenhouse gas forcing is of much general interest. Previous studies have suggested a poleward shift in the location of these cyclones, but how the intensity may change remains uncertain, especially in terms of maximum wind speed. In this study, projected changes in extreme cyclones in the Southern Hemisphere, based on 26 models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5), are presented. Multiple definitions of extreme cyclones have been examined, including intensity exceeding constant thresholds of sea level pressure perturbations, 850-hPa vorticity, and 850-hPa winds, as well as variable thresholds corresponding to a top-5 or top-1 cyclone per winter month in these three parameters and the near-surface winds. Results presented show that CMIP5 models project a significant increase in the frequency of extreme cyclones in all four seasons regardless of the definition, with over 88% of the models projecting an increase. Spatial patterns of increase are also consistent, with the largest increase projected between 45° and 60°S, extending from the South Atlantic across the south Indian Ocean into the Pacific. The projected increases in cyclone statistics are consistent with those in Eulerian statistics, such as sea level pressure (SLP) variance. However, while the projected increase in SLP variance can be linked to increase in the mean available potential energy (MAPE), the increases in cyclone statistics are not well correlated with those in MAPE.


Author(s):  
G.M. Rebel

The article analyzes the novel “Philellin” by L.A. Yuzefovich, the main attention is paid to the method of narration, the system of characters, the typological characteristics of the main character and the genre features of the work. The novel is a collection of documents of different genres, which together form a story about the events of the liberation war in Greece in the 20s of the XIX century. Almost all of Yuzefovich's characters act simultaneously as subjects of the narrative and participants in the events. The exception is Alexander I, because he is “silent” (his point of view is broadcast by his secretary Yelovsky) and "inactive". Despite the importance of the figure of the Russian emperor in the plot of the novel, for these reasons, Alexander “gives way” to the place of the main character to a fictional character - Grigory Mossepanov, whose fate forms the plot outline of the novel. Mossepanov is not only an important participant in the events, but also one of the main subjects and objects of the narrative. In literary criticism, the hero is given typological definitions of Don Quixote, Petrushka, “a little man”. This article offers a more appropriate definition of the character and fate of Mossepanov - “enchanted wanderer”, which is confirmed by the comparison of the characters of L. Yuzefovich and N. Leskov. The key plot role of the Russian philhellene, the peculiarities of his character and fate largely determine the genre nature of the work as a historical and mythological novel.


2019 ◽  
Vol 58 (05) ◽  
pp. 371-378
Author(s):  
Alfred O. Ankrah ◽  
Ismaheel O. Lawal ◽  
Tebatso M.G. Boshomane ◽  
Hans C. Klein ◽  
Thomas Ebenhan ◽  
...  

Abstract 18F-FDG and 68Ga-citrate PET/CT have both been shown to be useful in the management of tuberculosis (TB). We compared the abnormal PET findings of 18F-FDG- and 68Ga-citrate-PET/CT in patients with TB. Methods Patients with TB on anti-TB therapy were included. Patients had a set of PET scans consisting of both 18F-FDG and 68Ga-citrate. Abnormal lesions were identified, and the two sets of scans were compared. The scan findings were correlated to the clinical data as provided by the attending physician. Results 46 PET/CT scans were performed in 18 patients, 11 (61 %) were female, and the mean age was 35.7 ± 13.5 years. Five patients also had both studies for follow-up reasons during the use of anti-TB therapy. Thirteen patients were co-infected with HIV. 18F-FDG detected more lesions than 68Ga-citrate (261 vs. 166, p < 0.0001). 68Ga-citrate showed a better definition of intracerebral lesions due to the absence of tracer uptake in the brain. The mean SUVmax was higher for 18F-FDG compared to 68Ga-citrate (5.73 vs. 3.01, p < 0.0001). We found a significant correlation between the SUVmax of lesions that were determined by both tracers (r = 0.4968, p < 0.0001). Conclusion Preliminary data shows 18F-FDG-PET detects more abnormal lesions in TB compared to 68Ga-citrate. However, 68Ga-citrate has better lesion definition in the brain and is therefore especially useful when intracranial TB is suspected.


Author(s):  
Ab Rahman A F ◽  
Md Sahak N. ◽  
Ali A. M.

Objective: Once daily dosing (ODD) aminoglycoside is gaining wide acceptance as an alternative way of dosing. In our setting it is the regimen of choice whenever gentamicin is indicated. The objective of this study was to evaluate the practice of gentamicin ODD in a public hospital in Malaysia. Methods: We conducted a retrospective review of medical records of patients on gentamicin ODD who were admitted to Hospital Melaka during January 2002 until March 2010. All adult patients who were on ODD gentamicin with various level of renal function were included in the study. Patients on gentamicin less than 72 hours and pregnant women were excluded. Results: From 110 patients, 75 (68.2%) were male and 35 (31.8%) were female. Indications for ODD gentamicin included pneumonia, 34 (31.0%) neutropenic sepsis, 27 (24.5%) and sepsis, 11 (10.0%). The mean dose and duration of gentamicin was 3.2 mg/kg/day and 7 days, respectively. Almost all patients were on gentamicin combined with other antibiotics. Clinical cure based on fever resolution was found in 89.1% of patients treated with ODD. Resolution of fever took an average of 48 hours after initiation of therapy. The evaluation for bacteriologic cure could not be performed because of insufficient data on culture and sensitivity. Out of 38 patients with analyzable serum creatinine data, four patients might have developed nephrotoxicity. Conclusion: In our setting, lower dosages of ODD gentamicin when used in combination with other antibiotics seemed to be effective and safe in treating most gram negative infections.


2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>


2017 ◽  
Vol 4 (1) ◽  
pp. 70
Author(s):  
Sri Sabakti

This research is aimed to expose the narrative structure of the novel Ca Bau Kan by using semiotical theory. The source of the data is the novel Ca Bau kan written by Remy Silado and published by KPG, eight edition, 2004. The data is collected by doing the library research. The teory applied in this research is the emiotical theory, especially the literary analysis of Subur Laksono Wardoyo that the analysis of the text of prose can be applied by using three fases; the analysis of the basic scheme narrative, the analysis of mean signifier, and the analysis of syntagmatics and pragmatics. The result of this research showed that the narrative structure in the novel CBK that (1) the life of Tinung before being a ca bau kan, (2) the life of Tinung as a ca bau kan, and (3) the life of Tinung after not being a ca bau kan anymore. Based on the narrative structure, it was found that “ Love is only one. No measurement is needed” is the mean signifier and able to be clarified by the analysis of syntagmatics-paradigmatics based on the biner oposition of weak x strong.AbstrakPenelitian ini bertujuan mengungkapkan stuktur narasi dalam novel Ca Bau Kan (CBK) dengan menggunakan teori semiotika. Penelitian ini menggunakan sumber data novel CBK karya Remy Silado yang diterbitkan oleh KPG, cetakan kedelapan tahun 2004. Pengumpulan data dilaksanakan dengan teknik kepustakaan. Teori yang digunakan dalam penelitian ini adalah teori semiotika, khususnya analisis sastra menurut Subur Laksono Wardoyo bahwa analisis teks prosa dapat dilakukan melalui tiga tahap, yaitu: analisis skema naratif dasar, analisis signifier utama, dan analisis sintagmatik-paradigmatik. Hasil penelitian menggambarkan bahwa struktur narasi pada novel CBK adalah sebagai berikut: 1) kehidupan Tinung sebelum menjadi ca bau kan, 2) kehidupan Tinung sebagai ca bau kan, dan 3) kehidupan Tinung setelah tidak menjadi ca bau kan. Berdasarkan struktur narasi, maka didapatkan bahwa “Cinta cuma satu, kagak perlu takaran” merupakan penanda utama dan dapat diperjelas melalui analisis sintagmatik-paradigmatik yang didasarkan atas sebuah oposisi biner lemah x kuat.


Author(s):  
Anatoly S. Kuprin ◽  
Galina I. Danilina

The purpose of this study is the analysis of limit situation in the narrative of war. The material of the study is the novel of Daniil Granin “My Lieutenant” and related texts. In the first part of the paper, the authors explore existing approaches to the term “limit situation” and similar concepts into scientific and philosophical traditions; limits of its applicability in literary studies and its relation to the categories of “narrative instances” and “event”. Proposed a literary-theoretical definition of the limit situation, which can be used in the analysis of fiction texts. Existing approaches to the examination of the situation of war are analyzed: philosophical-existential, psychoanalytic, sociological, literary. In the second part of the paper, the authors propose their method for analyzing limit situations in texts about war, which basis on existing approaches and preserves the text-centric principle of studying the structure of the story. Two interrelated areas of research have been identified: the study of war as a continuous limit situation in the intertextual aspect (the discourse of war); the study of limit situations (death, suffering, guilt, accident) in the narrative of war as part of a specific text. In the third part of the scientific work,the analysis of war as a continuous limit situation results in the study of the concept of “limit” (border) in a fiction text. The role of “limit” (border) concept in the texts about the war is studied, the possible types of limits in the discourse of war are examined. Limit situations in the narrative of war are analyzed on the basis of the novel “My Lieutenant” by Daniil Granin. A review of journalistic and scientific works about the novel revealed both the continuity and the differences between the novel and the “lieutenant” prose of the 20th century. An analysis of the limit situations in the novel revealed their key position in the narrative. These situations are independent of the fiction time, of the fluctuation of the point of view’; the function of the abstract author is to build the narrative as a “directive” immersion of the hero and narrator in these situations.


2019 ◽  
Vol 29 (1) ◽  
pp. 243-258

The essay investigates the phenomenon of laziness by first analyzing the opposition between laziness and the good. Both utility and the good make reference to labor. This opposition between labor and laziness is pivotal in Oblomov, Ivan Goncharov’s famous novel written in 1859. It marks a radical transition from a feudal paradigm to a capitalistic one. The two main characters in the novel are Ilya Ilyich Oblomov, a Russian, and Andrey Ivanovich Stolz, a German, who together seem to personify the contradiction between laziness and labor. But the purpose of the essay is to deconstruct that opposition. In this connection, one can cite Kazimir Malevich, who maintained that laziness is the Mother of Perfection and is always unconsciously inherent in the conscious intent to work. Analysis of the Latin concepts of otium and negotium indicates that the laziness/labor opposition may be deconstructed as a dialectic between labor and its opposite. In other words, laziness does not stand in contradiction to labor but is instead its inseparable dialectical other. In the last part of the essay, the article considers the thinking of Anatoly Peregud, a poet who spent almost all his life in a psychiatric hospital. According to Peregud, Lenin derived his pseudonym from the Russian linguistic root “len” (laziness) in order to make laziness central to communism. For his part, Lenin saw Oblomov as an emblem of the main obstacle standing in the way of communism.


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