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See detailVentilatory response to helium-oxygen breathing in exercising ponies
Art, Tatiana ULg; Lekeux, Pierre ULg

in Archives Internationales de Physiologie et de Biochimie (1989), 97(3), 40

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See detailVentral porencephaly: a cerebral defect associated with multiple congenital anomalies.
Stewart, R. M.; Williams, R. S.; Lukl, P. et al

in Acta Neuropathologica (1978), 42(3), 231-5

An infant with multiple congenital anomalies was found at autopsy to have a porencencephalic defect on the ventral surface of the left frontal lobe. The intracranial defect was seen in association with an ... [more ▼]

An infant with multiple congenital anomalies was found at autopsy to have a porencencephalic defect on the ventral surface of the left frontal lobe. The intracranial defect was seen in association with an anomalous configuration of the circle of Willis. The zone of tissue destruction corresponded to the vascular territory of the anterior choroidal and lenticulo-striate branches of the proximal middle cerebral arteries, which were absent on the left. The developmental anomaly of the circle of Willis may have predisposed to tissue destruction by compromising cerebral perfusion at midgestation, a stage of rapid brain growth. [less ▲]

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See detailVentricular aneurysm versus pseudoaneurysm: role of multi-imaging modality.
DAVIN, Laurent ULg; BRUYERE, Pierre-Julien ULg; LANCELLOTTI, Patrizio ULg

in Archives of Cardiovascular Diseases (2008), 101(2), 135

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See detailVentriculitis caused by Aspergillus fumigatus in a child with central nervous system tuberculosis
Antachopoulos, Charalampos; STERGIOPOULOU, Theodouli ULg; Simitsopoulou, Maria et al

in Mycoses (2011), 54(5), 627-30

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See detailVentriculo-Arterial Coupling: an ideal problem for collaboration between clinicians and engineers
MORIMONT, Philippe ULg; Desaive, Thomas ULg; Chase et al

in Proceedings of CONTROL 2010 (2010)

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See detailVenture Creation Intentions and Midlife Crisis
Heuer, Annamaria ULg; Surlemont, Bernard ULg

Conference (2008, November 21)

Aim of the paper This paper aims to analyse the relationship between life stages and the drivers of venture creation intention and, hence, the venture creation. The objective is to analyse the extent to ... [more ▼]

Aim of the paper This paper aims to analyse the relationship between life stages and the drivers of venture creation intention and, hence, the venture creation. The objective is to analyse the extent to which the single-minded focus of most policy measures on early adult population to spur intention is not understating the importance of adapting the approach to specific life stages of the target population. Using different conceptualisations of age biological, psychological, organisational and life span related , we will take here a closer look at the midlife age cluster, centred around the 35th year. Contribution to the literature Numerous studies have applied models based on cognition research to understand entrepreneurial intentions and the factors that impact them (e.g. Autio et al., 2001; Kolvereid, 1996; Krueger, Reilly and Carsrud, 2000; Kristiansen and Indarti, 2004). However, besides a few exceptions, such as Douglas and Shepherd (2002) or Davidsson (1995), most scholars have conducted their studies on university students, due to their advantages as sample, like easier information access and homogeneity of population. Not much attention has been paid to the potential influence of the life-stage factor and its potential impact on policy formulation. Taking a chronological age perspective, Levinson (1986) proposed that there is an “underlying order in human life course”, no matter what occupation or background people have. He conceived life as a sequence of eras, each of them with a specific biopsychosocial character and each of them contributing to the whole life cycle. Major changes of life characteristics occur in the cross-era transition, but also within a life stage. According to this approach, every life stage has tasks to be accomplished (Levinson et al., 1978). From an entrepreneurship perspective, it is especially interesting to introduce this model by taking a closer look at stages of “Early adulthood” (age c. 20-40). “Early adult transition” (age c. 17-22) for instance is characterised by reflections about one’s own place in the world independent from the institutions of youth (parents, school…). It is also about testing one’s initial choices about preferences for the adult life. This is in line with the “impressionable years” hypothesis, which is based on the notion that key attitudes, beliefs, and values are of great plasticity during the early adult years (Sears, 1975; Visser et al., 1998), while suggesting that susceptibility to change in attitude falls sharply after early adult years and stays on a low level for the rest of the life cycle. These attitudes, beliefs and values build an essential pillar of intentions, and are thus relevant for the study of entrepreneurial intentions. A vast quantity of policies trying to foster entrepreneurship usually target the “Early adult transition” cluster, arguing that entrepreneurial intention is created at this stage, even though, it is rather the entrepreneurial attitude that comes into existence at this point. Another remarkable and relevant milestone of Levinson’s life stage development model is linked to the age of c. 29 to 33, called “Thirties transition”, and which is dealing with the evaluation of the accomplishments of the twenties and the adjustments to the adopted life structure. It is a time characterised by instability and change, in which it is to be expected that commitment and satisfaction will remain low: for instance, individuals at this era will express greater intentions to leave their company (Ornstein et al., 1989), and possibly, to create one. This may provide another explanation to why it is observed that the age for new venture creation is around 35 years. Given that entrepreneurial activity does not only depend on the desirability and feasibility of entrepreneurship, but also upon the desirability and feasibility of employment (Kolvereid, 1996b), this could help to explain the increased levels of early-stage entrepreneurship in this age-cluster, and is leading to the following questions: (i) If potential entrepreneurs in their thirties are much more susceptible to change, and considering the aging population and the expected increase of retirement age in the western world the economic importance of “older” entrepreneur’s is likely to increase (Weber, 2004), why then not stimulate them more? (ii) If attitude gets more rigid with age, is applying the same policy strategies to “younger” and “older” potential entrepreneurs really the most efficient approach, or are, this way, policy-makers failing to stimulate a part of the population? (iii) If policy-making is about trying to sell an idea and make the population buy it, why are we then ignoring basic marketing segmentation strategies? In order to provide to our knowledge the first more holistic picture of possible adult development related impacts on entrepreneurial intention, we will proceed in a rather systematic way by choosing different perspectives of aging such as chronological, psychological and organisational, focusing on and around the “midlife” age cluster. Methodology This paper is conceptual in nature, transferring important ideas from adult-development studies to the domain of entrepreneurship. Through our argumentation we will show that an in-depth analysis, in form of comparative studies, of aging-related changes of the factors determining intention is timely. Results To date, there has been only sporadic, short argumentation for aging-related changes of intentional antecedents, such as “organisational age” impacting perceived behavioural control or life-span age impacting how to bear the uncertainty of income from self-employment activity (Shane, 2003). We will provide a more rigorous review of this problematic, and by that hope to contribute to a better understanding of sometimes ambiguous details of study outcomes. Bibliography Aution, E., Keeley, R. H. (2001), ”Entreprenerial intent among students in Scandinavia and in the USA”, Entreprise and Innovation Management Studies, Vol. 2, No. 2, pp.145-160 Davidsson, P. (1995), ”Determinants of entrepreneurial intentions”, Paper prepared for RENT IX Workshop, Piacenza, Italy Douglas, E. J., Dean, A. S. (2002), ”Self-employment as a Career Choice: Attitudes, Entrepreneurial Intentions, and Utility Maximization”, Entrepreneurship: Theory & Practice, Vol. 26, Issue 3, pp. 81-90 Kolvereid, L. (1996), ”Organizational employment versus self-employment: reasons for career choice intentions”, Entrepreneurship: Theory & Practice, Vol. 20, Issue 3, pp. 23-31 Kolvereid, L. (1996b), ”Prediction of Employment Status Choice Intentions”, Entrepreneurship: Theory & Practice, Vol. 21, Issue 1, pp. 47-57 Kristiansen, S., Indarti, N. (2004), ”Entrepreneurial intention among Indonesian and Norwegian students”, Journal of Entreprising Culture, Vol. 12, No. 1, pp. 55-78 Krueger, N. F., Reilly, M. D., Carsrud, A. L. (2000), ”Competing models of entrepreneurial intentions”, Journal of Business Venturing, Vol. 15, Issue 5/6, pp. 411-432 Levinson, D. J., Darrow, C. N., Klein, E. B., Levinson, M. H. and McKee; B. (1978), ”The seasons of a Man’s Life”, Alfred A. Knopf, New York Levinson, D. J. (1986), ”A Conception of Adult Development”, American Psychologist, Vol. 41, No. 1, pp. 3-13 Ornstein, S., Cron, W. L., Slocum, J. W. Jr. (1989), ”Life stage versus career stage: A comparative test of theories of Levinson and Super”, Journal of organizational behaviour, Vol. 10, pp. 117-133 Sears, D. O. (1975), ”Political socialization”, In F.I. Greenstein and N. W. Polsby (Eds.), Handbook of political science, MA: Addison-Wesley Shane, S. (2003), ”A General Theory of Entrepreneurship – The Individual-Opportunity Nexus”, Edward Elgar Publishing, Cheltenham Visser, P. S., Krosnick, J. A. (1998), ”Development of Attitude Strength Over the Life Cycle: Surge and Decline”, Journal of Personality and Social Psychology, Vol. 75, No. 6, pp. 1389-1410 Weber, P., Schaper, M. (2004), ”Understanding the grey entrepreneur”, Journal of Entreprising Culture, Vol. 12, No. 2, pp. 147-164 [less ▲]

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See detailVenture Creation Intentions and the Seasons of Adult Development
Heuer, Annamaria ULg; Surlemont, Bernard ULg

Conference (2008, November 06)

Objectives: The objective of the paper is to identify the potential impact of different forms of aging (e.g. biological, psychological and psychosocial aging) on entrepreneurial intention. Thus, the key ... [more ▼]

Objectives: The objective of the paper is to identify the potential impact of different forms of aging (e.g. biological, psychological and psychosocial aging) on entrepreneurial intention. Thus, the key focus will be on aging-related changes of attitudes, subjective norms and feasibility perceptions and their influence on intention. Prior work: Numerous studies have applied cognition research-based models to understand the factors that impact entrepreneurial intentions (e.g. Davidsson, 1995; Kolvereid, 1996; Krueger, Reilly and Carsrud, 2000; Autio et al., 2001; Douglas and Shepherd, 2002; Kristiansen and Indarti, 2004). Most scholars, however, have conducted their studies on university students (e.g. Van Gelderen et al., 2006). This choice is mostly motivated by an easier access to data. As a consequence, this may have introduced a bias that underestimates the potential influence of life-stage-related differences on entrepreneurial intention. Approach: The paper will present a literature review of the theories that look at the impact of aging on career intentions (for instance, Lévesque and Minniti, 2006; Ornstein et al., 1989). The approach is to start on the structure of the intentions model (Ajzens’ Theory of Planned Behaviour) as a framework to integrate these pieces of research. Results: This paper is conceptual in nature, transferring important ideas of adult-development to the domain of entrepreneurship. The argumentation will show the differences in perceived desirability and feasibility are related to aging, such as high plasticity of attitude in early adulthood (e.g. Visser et al., 1998), higher change susceptibility in mid-age (Levinson, 1986; Lévesque and Minniti, 2006), and dominant self-limiting roles and decreasing willingness to bear uncertainty in the later eras (Greller, 1995; Shane, 2003). Ultimately, the paper will contribute to formulate hypotheses relating aging stages and possible drivers of entrepreneurial intention. Implications: If the drivers of entrepreneurial intention change according to age, then programmes to stimulate entrepreneurship may have to be adapted according to the target audience. If potential entrepreneurs at later stages such as the “thirties transition” are more susceptible to change, and considering that due to population aging and increasing retirement age in the western world the economic importance of “older” entrepreneur’s is likely to increase, why not stimulate them more? Value: To date, there have only been sporadic, short argumentations for aging-related changes of intentional antecedents. We fill this gap and provide a more rigorous review of this problematic. [less ▲]

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See detailVenture Philanthropy: When Philanthropy Meets Social Entrepreneurship
Defourny, Jacques ULg; Nyssens, Marthe; Thys, Séverine

in Jung, Tobias; Phillips, Susan D.; Harrow, Jenny (Eds.) The Routledge Companion to Philanthropy (2016)

Detailed reference viewed: 105 (2 ULg)
See detailVénus et Aphrodite : 60 ans après la thèse de Robert Schilling
Pirenne-Delforge, Vinciane ULg; Pironti, Gabriella

in Belayche, Nicole; Lehmann, Yves (Eds.) Religions de Rome. Dans le sillage des travaux de Robert Schilling (2017)

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See detailVenus Express observations of the Venus O2 and NO nightglow: distribution and constraints on vertical transport
Gérard, Jean-Claude ULg; Cox, Cédric ULg; Saglam, Adem ULg et al

Conference (2007, April)

Observations have been carried out in the infrared with VIRTIS and the ultraviolet with SPICAV to measure the distribution of the O2 (1 g) nightglow emission at 1.27 μm and the nitric oxide gamma and ... [more ▼]

Observations have been carried out in the infrared with VIRTIS and the ultraviolet with SPICAV to measure the distribution of the O2 (1 g) nightglow emission at 1.27 μm and the nitric oxide gamma and delta bands between 190 and 300 nm. These observations were collected in the tangent limb mode, which maximizes the time period spent by the line of sight through the airglow layer. The O2 (1 g) emission is excited by three-body recombination of O atoms produced on the day side and carried by the general thermospheric circulation to the night side. It is very variable in brightness and has a peak located between 95 and 100 km. The NO airglow is produced by radiative recombination of O atoms with N(4S) resulting from N2 photodissociation and reaches a maximum near 110 km.We combine the altitude and brightness information from the two emissions with simulations of a chemical diffusive model to determine the values of the vertical fluxes of O and N atoms and the strength of the eddy mixing which carries both types of atoms from above the turbopause into the recombination layer.We find that O fluxes on the order of a few 1012 atoms/cm2 s and N fluxes about 1010 atoms/cm2 s can reproduce the observations. The variability of the airglow emissions and the altitude-brightness relation will also be discussed and compared with model predictions. [less ▲]

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See detailVenus express: Highlights of the nominal mission
Titov, D. V.; Svedhem, H.; Taylor, F. W. et al

in Solar System Research (2009), 43

Venus Express is the first European (ESA) mission to the planet Venus. Its main science goal is to carry out a global survey of the atmosphere, the plasma environment, and the surface of Venus from orbit ... [more ▼]

Venus Express is the first European (ESA) mission to the planet Venus. Its main science goal is to carry out a global survey of the atmosphere, the plasma environment, and the surface of Venus from orbit. The payload consists of seven experiments. It includes a powerful suite of remote sensing imagers and spectrometers, instruments for in-situ investigation of the circumplanetary plasma and magnetic field, and a radio science experiment. The spacecraft, based on the Mars Express bus modified for the conditions at Venus, provides a versatile platform for nadir and limb observations as well as solar, stellar, and radio occultations. In April 2006 Venus Express was inserted in an elliptical polar orbit around Venus, with a pericentre height of Ë 250 km and apocentre distance of Ë 66000 km and an orbital period of 24 hours. The nominal mission lasted from June 4, 2006 till October 2, 2007, which corresponds to about two Venus sidereal days. Here we present an overview of the main results of the nominal mission, based on a set of papers recently published in Nature, Icarus, Planetary and Space Science, and Geophysical Research Letters. [less ▲]

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See detailVenus III book: aeronomy of the upper atmosphere
Gérard, Jean-Claude ULg; Bougher, Stephen; Drossart, Pierre et al

Conference (2014, September 12)

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See detailVenus night airglow and implications for thermospheric composition and dynamics
Gérard, Jean-Claude ULg; Saglam, Adem ULg; Cox, Cédric ULg et al

Conference (2008)

Spatially resolved spectra of the NO delta and gamma ultraviolet bands have been obtained from 80 to 130 km on the Venus night side with the SPICAV instrument on board Venus Express. This NO airglow ... [more ▼]

Spatially resolved spectra of the NO delta and gamma ultraviolet bands have been obtained from 80 to 130 km on the Venus night side with the SPICAV instrument on board Venus Express. This NO airglow emission results from radiative recombination of oxygen and nitrogen atoms created on the dayside and transported by the subsolar to antisolar global circulation. Spectral images of the O2 (1 â delta g ) at 1.27 µm have also been made with the VIRTIS-M instrument both at nadir and at the limb. The O2 (1 â g ) emission is produced by three-body recombination of O atoms giving rise to an airglow layer near 96 km. The brightness of both emissions changes by over an order of magnitude. They also show variations in the altitude of the peak emission, with larger variability of the NO airglow. The characteristics of both airglows and their implications on global circulation and vertical transport on the nightside will be discussed. Concurrent observations of both limb airglows will be described. It will be shown that limb observations of the vertical and latitudinal distribution of the 1.27 µm emission make it possible to remotely determine the density of atomic oxygen in the upper mesosphere and improve current atmospheric models. One-dimensional models of the O and N distributions will be presented and global properties of the 1-D parameterization of turbulent transport will be discussed. [less ▲]

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See detailVenus Night Airglow Distibutions and Variability: NCAR VTGCM Simulations
Brecht, Amanda; Bougher, S.; Gérard, Jean-Claude ULg et al

in Bulletin of the American Astronomical Society (2008, September 01)

The National Center for Atmospheric Research (NCAR) thermospheric general circulation model for Venus (VTGCM) is producing results that are comparative to Pioneer Venus and Venus Express data. The model ... [more ▼]

The National Center for Atmospheric Research (NCAR) thermospheric general circulation model for Venus (VTGCM) is producing results that are comparative to Pioneer Venus and Venus Express data. The model is a three dimensional model that can calculate temperatures, zonal winds, meridional winds, vertical winds, and concentration of specific species. The VTGCM can also compute the O[SUB]2[/SUB]-IR and NO-UV night airglow intensity distributions. With a lower boundary set at 70 Km and a range of sensitivity tests, the VTGCM is able to show consistent set of results with the nightside temperature and the night airglows. These results can show possible controlling parameters of the O[SUB]2[/SUB]-IR, NO-UV night airglow layers, and the nightside hot spot. Being able to understand the night airglow distribution and variability provides valuable insight into the changing circulation of Venusâ upper atmosphere and leads to an overall planetary perception of the atmospheric dynamics. [less ▲]

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See detailVenus night side measurements of winds at 115 km altitude from NO bright patches tracking.
Bertaux, J.-L.; Gérard, Jean-Claude ULg; Stiepen, Arnaud ULg et al

Conference (2013, June)

N and O atoms produced by photo-dissociation of CO2 and N2 on the day side of Venus are transported to the night side in the thermospheric circulation. When the air parcel is descending, the recombination ... [more ▼]

N and O atoms produced by photo-dissociation of CO2 and N2 on the day side of Venus are transported to the night side in the thermospheric circulation. When the air parcel is descending, the recombination N+O→ NO produces the famous γ and δ bands of NO emission. Pioneer Venus (1978) suggested that the statistical center of the emission is off from the anti-solar point, about one- two hours in Local time after midnight. This is confirmed from SPICAV/VEX results, and the explanation generally accepted is the influence of retrograde super rotation. However, the emission takes place at 115 km, while VIRTIS/VEX, with maps of O2 emission (peak altitude 95 km) in the night side of Venus (recombination of O+O coming from the day side), has shown that the maximum of emission is statistically centered on the antisolar point. Therefore, there is no influence of super-rotation at 95 km. One way to explain this paradox is that the cause of the super rotation is different at 115 km and in the lower atmosphere. Alternately, some gravity waves could propagate from below, crossing the altitude 95 km with minimal interaction, and breaking around 115, depositing their momentum. Another consideration is that the altitude of N2 photo-dissociation is higher in the thermosphere than CO2, therefore the thermospheric circulation pattern may be different for the transport of N atoms, and O atoms. We have started building maps of the NO emission by moving around the spacecraft along its orbit on the night side. The idea is that NO emission is concentrated generally in rather well defined patches of light. Therefore, by comparing maps taken at 1 hour or 24 hr interval, we can make a “bright patch tracking”, and derive directly the velocity of the moving air parcel containing N and O (we are aware that a part of the motion could be due to a phase shift of a gravity wave, if it has some influence on the NO emission). Preliminary results from this exercise with Venus Express will be presented and discussed. [less ▲]

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See detailVenus nightglow intensity and solar activity: any correlation?
Soret, Lauriane ULg; Gérard, Jean-Claude ULg

Conference (2015, May 26)

We examine if any correlation is observed between the brightness of the O2 nightside airglow and the EUV solar irradiance using the full database of VIRTIS IR images. We conclude that, as was the case for ... [more ▼]

We examine if any correlation is observed between the brightness of the O2 nightside airglow and the EUV solar irradiance using the full database of VIRTIS IR images. We conclude that, as was the case for the NO airglow observed during the Pioneer Venus mission, no response to solar activity is observed. [less ▲]

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See detailThe Venus nitric oxide night airglow - Model calculations based on the Venus Thermospheric General Circulation Model
Bougher, S. W.; Gérard, Jean-Claude ULg; Stewart, A. I. F. et al

in Journal of Geophysical Research (1990), 95

The mechanism responsible for the Venus nitric oxide (0,1) delta band nightglow observed in the Pioneer Venus Orbiter UV spectrometer (OUVS) images was investigated using the Venus Thermospheric General ... [more ▼]

The mechanism responsible for the Venus nitric oxide (0,1) delta band nightglow observed in the Pioneer Venus Orbiter UV spectrometer (OUVS) images was investigated using the Venus Thermospheric General Circulation Model (Dickinson et al., 1984), modified to include simple odd nitrogen chemistry. Results obtained for the solar maximum conditions indicate that the recently revised dark-disk average NO intensity at 198.0 nm, based on statistically averaged OUVS measurements, can be reproduced with minor modifications in chemical rate coefficients. The results imply a nightside hemispheric downward N flux of (2.5-3) x 10 to the 9th/sq cm sec, corresponding to the dayside net production of N atoms needed for transport. [less ▲]

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See detailVenus nitric oxide nightglow mapping from SPICAV nadir observations.
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Dumont, Maïté ULg et al

in Icarus (2013)

Nitric oxide δ (190-240 nm) and γ (255-270 nm) emissions on the Venus nightside have been observed with Venus Express SPICAV instrument operated in the nadir mode. These ultraviolet emissions arise from ... [more ▼]

Nitric oxide δ (190-240 nm) and γ (255-270 nm) emissions on the Venus nightside have been observed with Venus Express SPICAV instrument operated in the nadir mode. These ultraviolet emissions arise from the desexcitation of excited NO molecules created by radiative recombination of O(3P) and N(4S) atoms. These atoms are produced on the dayside of the planet through photodissociation of CO2 and N2 molecules and are transported to the nightside by the global subsolar to antisolar circulation. We analyze a wide dataset of nadir observations obtained since 2006 to determine the statistical distribution of the NO nightglow and its variability. Individual observations show a great deal of variability and may exhibit multiple maxima along latitudinal cuts. We compare this global map with the results obtained during the Pioneer-Venus mission and with the recent O2(a1Δg) nightglow map. The NO airglow distribution shows a statistical bright region extending from 01:00 and 03:30 local time and 25°N to 10°S, very similar to the Pioneer result obtained 35 years earlier during maximum solar activity conditions. The shift from the antisolar point and the difference with the O2 airglow indicate that superrotating zonal winds are statistically weak near 97 km, but play an important role in the lower thermosphere. We compare these results with other evidence for superrotation in the thermosphere and point out possible sources of momentum transfer. [less ▲]

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