scholarly journals The Role of Forcing in Cell Morphology and Evolution within Midlatitude Squall Lines

2006 ◽  
Vol 134 (12) ◽  
pp. 3714-3734 ◽  
Author(s):  
Brian F. Jewett ◽  
Robert B. Wilhelmson
Keyword(s):  
Cell Morphology ◽  
Three Dimensional ◽  
Leading Edge ◽  
Cell Interaction ◽  
Squall Lines ◽  
Convective Cells ◽  
High Bulk ◽  
Homogeneous Environment ◽  
Low Shear

Abstract This study assesses the role of mesoscale forcing on cell morphology and early evolution of midlatitude squall lines. The forcing chosen was a cold front, simulated to frontal collapse to produce a specific set of thermodynamic profiles at the leading edge of the front. Use of a realistic, balanced, and persistent forced state allowed a unique evaluation of its importance in thunderstorm evolution compared with a traditional homogeneous environment without forcing. Three-dimensional squall lines were modeled with and without the front present, in low and high bulk Richardson number environments. The forced convection evolved in significantly different ways than their isolated, unforced counterparts. In low-shear conditions, the line of isolated convective cells split, with the adjacent split cells interfering destructively with neighboring cells in the line. With forcing present, differences in anticyclonic cell intensity and propagation prevented this interaction from occurring, leading to longer-lived cyclonic convection despite a near-normal orientation between cloud-bearing shear and the convective line. The split-cell interaction also failed to occur under higher-shear conditions due to anticyclonic cell decay given the greater cyclonic hodograph curvature. In both low- and higher-shear environments, a strong bias toward cyclonic storms was noted with forcing present, due to shallower anticyclonic cells with the front present and to preexisting vorticity in the environment; updraft–vorticity correlations were skewed accordingly. Forcing also reduced the sensitivity of the evolving convection to detailed aspects of the initialization.

On the persistence of tropical shallow convective squall lines - the role of cold pools

2020 ◽  
Author(s):  
Ludovic Touzé-Peiffer ◽  
Nicolas Rochetin ◽  
Raphaela Vogel
Keyword(s):  
Wind Shear ◽  
Leading Edge ◽  
Critical Factor ◽  
Trade Wind ◽  
Squall Line ◽  
Cold Pools ◽  
Squall Lines ◽  
German Model ◽  
Convective Cells

<p>A considerable amount of literature has been devoted to the study of strong convective squall line. In particular, many studies have noted the role of cold pools on the persistence of these squall lines. Observations and simulations have shown that squall lines are often associated with pools of air cooled by partial rain evaporation. Such cold pools spread at the surface and may initiate new convective cells at their edges, thus contributing to the maintenance of a squall line. Under which environmental conditions the lifting at the edges of cold pools is most efficient has been subject to many debates. Yet, it is generally acknowledged that the environmental wind shear is a critical factor in this process. </p><p>Recent observations and realistic simulations over the trade-wind region have revealed persistent structures of shallow cumuli associated with surface cold pools. We will call these structures shallow convective squall lines, due to their similarity with strong convective squall lines. Based on simulations from the German model ICON and on recent observations from the field campaign EUREC4A, we will study the characteristics of these shallow convective squall lines and their lifecycle. Similarly to strong convective squall lines, shallow convective squall lines organized around a leading edge composed by many updrafts and downdrafts feeding the surface cold pools. We will see that the environmental wind shear plays a key role in the persistence of these shallow convective squall line, and we will compare our findings with classical theories for strong convective squall lines.</p>

scholarly journals Three-dimensional low shear culture of Mycobacterium bovis BCG induces biofilm formation and antimicrobial drug tolerance

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Daire Cantillon ◽  
Justyna Wroblewska ◽  
Ian Cooper ◽  
Melanie J. Newport ◽  
Simon J. Waddell
Keyword(s):  
Transcriptional Profiling ◽  
Three Dimensional ◽  
Drug Tolerance ◽  
Antimicrobial Drug ◽  
Bacterial Disease ◽  
Biofilm Growth ◽  
Liquid Suspension ◽  
Free Media ◽  
Low Shear

AbstractMycobacteria naturally grow as corded biofilms in liquid media without detergent. Such detergent-free biofilm phenotypes may reflect the growth pattern of bacilli in tuberculous lung lesions. New strategies are required to treat tuberculosis, which is responsible for more deaths each year than any other bacterial disease. The lengthy 6-month regimen for drug-sensitive tuberculosis is necessary to remove antimicrobial drug tolerant populations of bacilli that persist through drug therapy. The role of biofilm-like growth in the generation of these sub-populations remains poorly understood despite the hypothesised clinical significance and mounting evidence of biofilms in pathogenesis. We adapt a three-dimensional Rotary Cell Culture System to model M. bovis BCG biofilm growth in low-shear detergent-free liquid suspension. Importantly, biofilms form without attachment to artificial surfaces and without severe nutrient starvation or environmental stress. Biofilm-derived planktonic bacilli are tolerant to isoniazid and streptomycin, but not rifampicin. This phenotypic drug tolerance is lost after passage in drug-free media. Transcriptional profiling reveals induction of cell surface regulators, sigE and BCG_0559c alongside the ESX-5 secretion apparatus in these low-shear liquid-suspension biofilms. This study engineers and characterises mycobacteria grown as a suspended biofilm, illuminating new drug discovery pathways for this deadly disease.

Hydraulic jumps at boundaries in rotating fluids

1996 ◽  
Vol 324 ◽  
pp. 55-82 ◽  
Author(s):  
Alexey V. Fedorov ◽  
W. Kendall Melville
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Hydraulic Jumps ◽  
Strong Nonlinearity ◽  
Rotating Fluids ◽  
Boundary Layer Region ◽  
Layer Region ◽  
Moderate Mass ◽  
Permanent Form

We consider three-dimensional hydraulic jumps (shocks) propagating along boundaries in rotating fluids. This study is motivated by earlier work (Fedorov & Melville 1995), which dealt with the evolution to breaking of nonlinear Kelvin waves. We obtain the jump relations and derive an evolution equation for the jump as it propagates along the boundary. It is shown that after some initial adjustment the Kelvin-type jump assumes a permanent form and propagates with a constant velocity along the boundary or the coast. At some distance offshore the jump becomes oblique to the coastline, and the final shape of the jump and its speed depend only on the jump strength. The jump gives rise to a moderate mass transport offshore. The potential vorticity remains almost constant across the jump. The energy loss in the jump is proportional to the third power of the jump amplitude, which is similar to classical two-dimensional hydraulic jumps in non-rotating fluids. Jump properties are discussed for both weak and strong nonlinearity, and the role of a boundary layer region behind the leading edge of the jump is considered.

The Role of Three-Dimensional Imaging in Evaluation of the Sinonasal Mass

1996 ◽  
Vol 34 (1) ◽  
pp. 27
Author(s):  
Sue Yon Shim ◽  
Ki Joon Sung ◽  
Young Ju Kim ◽  
In Soo Hong ◽  
Myung Soon Kim ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Three Dimensional Imaging ◽  
Sinonasal Mass

Homogenization and Mass Identity vs. Individual Identity. An Analysis in the Light of the Theory of “The Three Dimensional Spiral of Sense

2016 ◽  
Vol 2 (2) ◽  
pp. 40
Author(s):  
Miriam Aparicio
Keyword(s):  
Three Dimensional ◽  
Individual Identity ◽  
Cognitive Effects ◽  
The Media

This study tests some hypotheses included in the psycho-social-communicational paradigm, which emphasizes the cognitive effects of the media and the role of the psychosocial subject as the recipient

Dysregulation of HOX as a Potential Therapeutic Target in Breast Cancer

2020 ◽  
Vol 27 ◽  
Author(s):  
Ji-Yeon Lee ◽  
Myoung Hee Kim
Keyword(s):  
Breast Cancer ◽  
Hox Genes ◽  
Therapeutic Potential ◽  
Expression Patterns ◽  
Genome Structure ◽  
Control Cell ◽  
Three Dimensional ◽  
Cellular Processes ◽  
Hox Protein

: HOX genes belong to the highly conserved homeobox superfamily, responsible for the regulation of various cellular processes that control cell homeostasis, from embryogenesis to carcinogenesis. The abnormal expression of HOX genes is observed in various cancers, including breast cancer; they act as oncogenes or as suppressors of cancer, according to context. In this review, we analyze HOX gene expression patterns in breast cancer and examine their relationship, based on the three-dimensional genome structure of the HOX locus. The presence of non-coding RNAs, embedded within the HOX cluster, and the role of these molecules in breast cancer have been reviewed. We further evaluate the characteristic activity of HOX protein in breast cancer and its therapeutic potential.

Central ossifying fibroma of mandible

2020 ◽  
Vol 13 (12) ◽  
pp. e239286
Author(s):  
Kumar Nilesh ◽  
Prashant Punde ◽  
Nitin Shivajirao Patil ◽  
Amol Gautam
Keyword(s):  
Fibrous Tissue ◽  
Three Dimensional ◽  
Facial Asymmetry ◽  
Ossifying Fibroma ◽  
Mandible Reconstruction ◽  
Three Dimensional Printing ◽  
Osseous Lesion ◽  
Large Size ◽  
Dimensional Printing

Ossifying fibroma (OF) is a rare, benign, fibro-osseous lesion of the jawbone characterised by replacement of the normal bone with fibrous tissue. The fibrous tissue shows varying amount of calcified structures resembling bone and/or cementum. The central variant of OF is rare, and shows predilection for mandible among the jawbone. Although it is classified as fibro-osseous lesion, it clinically behaves as a benign tumour and can grow to large size, causing bony swelling and facial asymmetry. This paper reports a case of large central OF of mandible in a 40-year-old male patient. The lesion was treated by segmental resection of mandible. Reconstruction of the surgical defect was done using avascular fibula bone graft. Role of three-dimensional printing of jaw and its benefits in surgical planning and reconstruction are also highlighted.

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