scholarly journals Spontaneous shape transition of Mn x Ge1− x islands to long nanowires

2021 ◽  
Vol 12 ◽  
pp. 366-374
Author(s):  
S Javad Rezvani ◽  
Luc Favre ◽  
Gabriele Giuli ◽  
Yiming Wubulikasimu ◽  
Isabelle Berbezier ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Shape Transition ◽  
Transition Mechanism ◽  
Mean Size ◽  
Alloy Nanowires ◽  
Elongation Process ◽  
Homogeneous Composition ◽  
Small Change ◽  
A Minor ◽  
Synthesis Approach

We report experimental evidence for a spontaneous shape transition, from regular islands to elongated nanowires, upon high-temperature annealing of a thin Mn wetting layer evaporated on Ge(111). We demonstrate that 4.5 monolayers is the critical thickness of the Mn layer, governing the shape transition to wires. A small change around this value modulates the geometry of the nanostructures. The Mn–Ge alloy nanowires are single-crystalline structures with homogeneous composition and uniform width along their length. The shape evolution towards nanowires occurs for islands with a mean size of ≃170 nm. The wires, up to ≃1.1 μm long, asymptotically tend to ≃80 nm of width. We found that tuning the annealing process allows one to extend the wire length up to ≃1.5 μm with a minor rise of the lateral size to ≃100 nm. The elongation process of the nanostructures is in agreement with a strain-driven shape transition mechanism proposed in the literature for other heteroepitaxial systems. Our study gives experimental evidence for the spontaneous formation of spatially uniform and compositionally homogeneous Mn-rich GeMn nanowires on Ge(111). The reliable and simple synthesis approach allows one to exploit the room-temperature ferromagnetic properties of the Mn–Ge alloy to design and fabricate novel nanodevices.

Adrenalectomy induces a decrease in the light scatter properties and amylase content of isolated zymogen granules from rat pancreas as analyzed by flow cytometry

1995 ◽  
Vol 147 (3) ◽  
pp. 431-440 ◽  
Author(s):  
A C Garcia-Montero ◽  
I De Dios ◽  
A I Rodriguez ◽  
A Orfao ◽  
M A Manso
Keyword(s):  
Flow Cytometry ◽  
Progressive Increase ◽  
Enzyme Concentration ◽  
Male Rats ◽  
Zymogen Granule ◽  
Light Scatter ◽  
Zymogen Granules ◽  
Mean Size ◽  
A Minor ◽  
Adrenalectomized Rats

Abstract The effect of glucocorticoid deprivation induced in male rats by adrenalectomy on the pancreatic zymogen granules was studied. Zymogen granules were purified from control, sham-operated and adrenalectomized animals studied 1, 3 and 7 days after surgery. The zymogen granules were characterized by flow cytometry, and in each granule the size (based on the forward or low angle light scatter (FSC) parameter), membrane complexity (based on side or 90° light scatter (SSC) parameter) and amylase content were evaluated. Amylase content/DNA ratio in pancreatic homogenates was also analyzed. The zymogen granules of the control rats were found to be distributed in two populations: a major one – R1 (95·45 ± 1·21%) – containing zymogen granules with a smaller mean size and complexity, and a minor population - R2 (4·45 ± 0·24%) – the granules of which had a mean size which was larger and more complex. At day +1 after adrenalectomy the zymogen granules were significantly (P<0·05) smaller than those of control animals. The R2 zymogen granules were similar to those from R1 as regards their size, but were more complex, suggesting that the immediate effect of glucocorticoid deprivation is to induce a depletion of the larger granules presumably belonging to the R2 population. The amount of amylase per granule did not vary at day +1 after adrenalectomy, although the amylase content/size ratio per granule was significantly (P<0·001) increased. This mechanism could be explained in terms of the existence of a bypass defined in the adrenalectomized animals between the granular content and cytosolic enzymes. Prolongation of the adrenalectomy period to 3 and 7 days resulted in a progressive increase in zymogen granule size and complexity, both parameters showing similar characteristics to those of the controls at day +7 after adrenalectomy. However, the percentage of zymogen granules within the R1 and R2 populations was clearly different from that of controls since the R2 population was much more numerous (11·25 ± 0·75% and 15·25 ± 1·15% (adrenalectomized rats at days +3 and +7 respectively) versus 4·45 ± 0·24% (controls)). An increase in the content of amylase per DNA was observed in adrenalectomized rats at day +1 although this transient effect cannot be related to glucocorticoid deprivation because it was also observed in sham-operated rats (day +1). However, a significant reduction, nearly 64%, in the amylase content/DNA ratio is produced by the absence of glucocorticoids 7 days after adrenalectomy and this is associated with a reduction in the content of amylase in each individual zymogen granule which reaches a minimum 3 days after adrenalectomy. It should be noted that, despite this, the enzyme concentration in each granule remains constant as there is a parallel decrease in the zymogen granule amylase content and size. Journal of Endocrinology (1995) 147, 431–440

scholarly journals 4.1 Meteors and Interplanetary Dust

1976 ◽  
Vol 31 ◽  
pp. 359-372 ◽  
Author(s):  
Peter M. Millman
Keyword(s):  
Chemical Composition ◽  
Interplanetary Dust ◽  
Physical Structure ◽  
Cumulative Number ◽  
Mean Size ◽  
The Mean ◽  
A Minor ◽  
Lower Limits ◽  
Lower Mass Limit ◽  
Number Of Particles

AbstractThe contribution of meteor observations to our knowledge of meteoroids and interplanetary dust is reviewed under four headings – flux, mass distribution, physical structure and chemical composition. For lower limits of particle mass ranging from 1 g to 10−5 g the mean cumulative flux into the earth’s atmosphere varies from 2 × 10−15 to 6 × 10−9 particles m−2 s−1 (2Πster)−1, and the mean size distribution of these particles is given by log N = C – 1.3 log M, where N is the cumulative number of particles counted down to a lower mass limit M, and C is a constant. The physical structure of meteoroids in the above range is essentially fragile, with generally low mean bulk densities that tend to increase with decrease in mass. A minor fraction, about 10 or 15 per cent, with orbits lying inside that of Jupiter, have densities several times the average densities, approaching those of the carbonaceous chondrites. The mean chemical composition of meteoroids seems to be similar to the bronzite chondrites for the elements heavier than number 10, but with the probable addition of extra quantities of the light volatiles H, C and O.

scholarly journals Modeling transient soil moisture limitations on microbial carbon respiration

2018 ◽  
Author(s):  
Yuchen Liu ◽  
Matthew J. Winnick ◽  
Hsiao-Tieh Hsu ◽  
Corey R. Lawrence ◽  
Kate Maher ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Column ◽  
Co2 Flux ◽  
Information Criterion ◽  
Order Model ◽  
First Order ◽  
Transition Mechanism ◽  
Dry Conditions ◽  
Shallow Soils ◽  
A Minor

Abstract. Observations show that soil microorganisms can survive periods of aridity and recover rapidly after wetting events. This behavior can be explained by a moisture-dependent adaptation (i.e. the ability to transition between a dormant state in dry conditions and an active state in wet conditions). Though this dynamic behavior has been previously incorporated into modeling frameworks, a direct comparison between a model application of this active-dormant transition mechanism and a more simplified first-order model has yet to be made. Here, we developed two models, one using simplified first-order kinetics and the other featuring a process-based rate expression incorporating the transition between active and dormant biomass. The two approaches are contrasted through a benchmarking exercise using a set of time series soil incubation datasets. We evaluated the two models using an Akaike Information Criterion (AIC). Combining the AIC evaluation and model-data comparison, we conclude that the dormancy-incorporated model performs better for shallow soils (above 108 cm), despite the added parameters required. In addition, this model is uniquely capable of reproducing transient CO2 flux rates associated with dynamic microbial response to changing soil moisture. In contrast, the first-order model achieves better AIC scores when simulating the incubation data obtained from our deepest soils (112–165 cm). However, deep soils constitute a minor contribution to the overall CO2 flux of an intact soil column. Thus, the dormancy-incorporated model may better simulate respiration of the whole soil.

scholarly journals Costs for switching partners reduce network dynamics but not cooperative behaviour

2014 ◽  
Vol 281 (1792) ◽  
pp. 20141661 ◽  
Author(s):  
Peter Bednarik ◽  
Katrin Fehl ◽  
Dirk Semmann
Keyword(s):  
Social Networks ◽  
Experimental Evidence ◽  
Dynamic Networks ◽  
Theoretical Work ◽  
Evolution Of Cooperation ◽  
Minor Role ◽  
Cooperative Behaviour ◽  
Group Members ◽  
Human Participants ◽  
A Minor

Social networks represent the structuring of interactions between group members. Above all, many interactions are profoundly cooperative in humans and other animals. In accordance with this natural observation, theoretical work demonstrates that certain network structures favour the evolution of cooperation. Yet, recent experimental evidence suggests that static networks do not enhance cooperative behaviour in humans. By contrast, dynamic networks do foster cooperation. However, costs associated with dynamism such as time or resource investments in finding and establishing new partnerships have been neglected so far. Here, we show that human participants are much less likely to break links when costs arise for building new links. Especially, when costs were high, the network was nearly static. Surprisingly, cooperation levels in Prisoner's Dilemma games were not affected by reduced dynamism in social networks. We conclude that the mere potential to quit collaborations is sufficient in humans to reach high levels of cooperative behaviour. Effects of self-structuring processes or assortment on the network played a minor role: participants simply adjusted their cooperative behaviour in response to the threats of losing a partner or of being expelled.

scholarly journals Injector Geometry Effect on Plain Jet Airblast Atomisation

1998 ◽  
Author(s):  
Paul J. O’Shaughnessy ◽  
Richard J. Bideau ◽  
Qing-ping Zheng
Keyword(s):  
Gas Flow ◽  
Velocity Ratio ◽  
Axial Distance ◽  
Flow Conditions ◽  
Geometry Effect ◽  
Breakup Mechanism ◽  
Jet Breakup ◽  
Term Change ◽  
Mean Size ◽  
Small Change

Airblast atomisation drop size is a function of the liquid and gas flow conditions. It is also subject to the atomisation geometry, or more specifically the jet breakup mechanism. Plain jet atomisation featuring coaxial air and fuel flows has been investigated to assess the injector geometry effect on the spray characteristics. Results from various flow conditions and atomiser configurations suggest that a prompt atomisation correlation that was evaluated for prefilming injectors can be applied to plain jet airblast atomisation, in a slightly modified form. Changes in the velocity term are necessary to fit the measured data. A scaling factor has been established to compensate for the velocity term change. This factor may also imply the underlying difference between flat sheet and round jet atomisation. The liquid atomisation mode is dependent not only on the manner of geometrical air-liquid contact but also on flow conditions. In this study, the combined air-fuel velocity ratio VR and Weber number (WeVR) is found to be a criteria that determines the air flow pattern influence on atomisation. Data from this experiment show that a small change in the axial distance between the liquid jet and air orifice entrance results in marked difference in spray drop mean size under low air momentum flow conditions.

Regulation of intracellular free Mg2+ and contraction in single adult mammalian cardiac myocytes

1994 ◽  
Vol 266 (1) ◽  
pp. C222-C233 ◽  
Author(s):  
H. S. Silverman ◽  
F. Di Lisa ◽  
R. C. Hui ◽  
H. Miyata ◽  
S. J. Sollott ◽  
...  
Keyword(s):  
Cardiac Myocytes ◽  
Ventricular Myocytes ◽  
Contractile Function ◽  
Energy State ◽  
Metabolic Inhibitors ◽  
Cellular Energy ◽  
Adult Rat ◽  
Isolated Cardiac Myocytes ◽  
Small Change ◽  
A Minor

Studies in isolated cardiac myocytes have increased our understanding of intracellular Ca2+ regulation. Because less is known about Mg2+ regulation, adult rat ventricular myocytes were loaded with the Mg(2+)-sensitive fluorescent probe mag-indo 1, and changes in intracellular Mg2+ concentration ([Mg2+]i) and cell length were examined under a variety of conditions. The fluorescent signal was calibrated intracellularly and found to differ slightly from that for the probe in solution. Roughly 40% of the signal was intramitochondrial; the remainder was localized in the cytosol. Basal [Mg2+]i averaged 1.02 +/- 0.03 mM (n = 53 cells). No change in [Mg2+]i was observed during a single electrically stimulated contraction, and only a minor increase was seen during rapid electrical stimulation, which was expected to raise intracellular Ca2+ concentration ([Ca2+]i) to approximately 1 microM. An acid shift in intracellular pH of approximately 1 pH unit was accompanied by a small change in [Mg2+]i (0.34 +/- 0.03 mM, n = 6, P < 0.05). No change in [Mg2+]i was observed when cells were superfused with 15 mM Mg2+, despite marked changes in contraction. [Mg2+]i more than doubled when cells were depleted of ATP by exposure to hypoxia or metabolic inhibitors. The increase in [Mg2+]i was abrupt and occurred at the time of the failure of contraction, plateauing as rigor contracture developed. Reoxygenation was accompanied by a gradual fall in [Mg2+]i in cells that recovered mechanical function, and in a subset of cells that underwent hypercontracture. Studies in cell suspensions confirmed that rapid cellular energy depletion was accompanied by increases in [Mg2+]i and parallel decreases in ATP. Thus [Mg2+]i was largely insensitive to changes in [Ca2+]i or pHi and extracellular [Mg2+] but was rapidly altered by changes in energy state in a manner that was related to specific changes in cell morphology and contractile function.

Explaining inertia in restoring estuarine dynamics in the Haringvliet (The Netherlands)

Water Policy ◽  
2014 ◽  
Vol 16 (5) ◽  
pp. 880-896 ◽  
Author(s):  
Peter Koenraad Marks ◽  
Lasse Martijn Gerrits ◽  
Sandra Bakker ◽  
Edwin Tromp
Keyword(s):  
The Netherlands ◽  
Policy Process ◽  
Estuarine Environment ◽  
Natural State ◽  
Policy Debate ◽  
Policy Proposal ◽  
Dutch Delta ◽  
Small Change ◽  
A Minor ◽  
Over Time

Following the 1953 flood, the Dutch delta has been shut off from the sea by a series of dams and dykes. This closing-off transformed the delta from a constantly changing estuarine environment into a freshwater body. A different way of thinking about ‘nature’ in the period 1970–1980 led to the policy proposal to transform the Haringvliet, one of the shut-off water bodies, back to its natural state. The intended first step was a minor change in the sluice control of the dam that separates the Haringvliet from the sea. However minor, this step was never taken and it is still an ongoing policy debate whether the sluice should be slightly opened or not. This paper presents a coevolutionary analysis of why such a seemingly small change could take so much time and effort to become actualized. We demonstrate that the course of the policy process is determined through patterns of reciprocity between the physical and societal systems. Effects of measures are unpredictable, and the desired state of this water basin greatly varies between actors and over time. It is a combination of these factors that explains why the sluice control has not been changed yet.

scholarly journals Speeded Up Robust Features Registration based Efficient Multi Row Panorama Generation

2021 ◽  
Vol 11 (2) ◽  
pp. 596-606
Author(s):  
S. Srujana ◽  
K. Sripal Reddy ◽  
D. Praveen Kumar
Keyword(s):  
Image Synthesis ◽  
Sift Algorithm ◽  
Speeded Up Robust Features ◽  
Current State ◽  
Starting Point ◽  
Long Time ◽  
Panoramic Images ◽  
A Minor ◽  
Synthesis Approach ◽  
Existing Structure

Most of the current panorama generation tools need an input to be provided along a single axis, which means that only a small portion of the scene is recorded. To achieve a wide area of viewers, this paper suggests a multi-row panoramic technique (multi-panorama method). A pan/tilt camera allows the automatic or manual scanning to occur over large horizontal and vertical perspectives. Frame pictures in horizontal and vertical perspectives to adjust to their coordinates and projections will need separate projection marks. And the picture should be continually updated over long time periods but it should also coordinate with other pictures in the spatial region, so as to provide an almost seamless appearance. Before these challenges, the first and before those, the worse, the game creates an optimum scanning route that encompasses the majority of the display and utilizes the reference frame as a starting point to stitch all the remainder. Multi-row stitching has a method of ensuring a minor alignment fault is located in the first column, followed by a small miss in the second row. It should be noted that mrpg suggests a multi-point stitch to reduce seams and compensate for distortion, and so that the existing structure is not divided around the panoramic canvas in an inaccurate manner. A new panoramic image synthesis approach was introduced that produced results that indicate panoramic images are higher quality than other current state- of-ofthe- the-the-art approaches, and- of pan or-the-art image techniques. Because of this, we used the surf feature instead of the sift algorithm, we got to results much more quickly and, we were able to achieve the targeted precision much faster.

How do memory modules differentially contribute to familiarity and recollection?

2019 ◽  
Vol 42 ◽  
Author(s):  
Olya Hakobyan ◽  
Sen Cheng
Keyword(s):  
Recognition Memory ◽  
Experimental Evidence ◽  
Subjective Experience ◽  
Target Article ◽  
Memory Modules ◽  
Familiarity And Recollection ◽  
Memory Contents

Abstract We fully support dissociating the subjective experience from the memory contents in recognition memory, as Bastin et al. posit in the target article. However, having two generic memory modules with qualitatively different functions is not mandatory and is in fact inconsistent with experimental evidence. We propose that quantitative differences in the properties of the memory modules can account for the apparent dissociation of recollection and familiarity along anatomical lines.

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