A method for reconstructing the variance of a 3D physical field from 2D observations: Application to turbulence in the ISM

We introduce and test an expression for calculating the variance of a physical field in three dimensions using only information contained in the two-dimensional projection of the field. The method is general but assumes statistical isotropy. To test the method we apply it to numerical simulations of hydrodynamic and magnetohydrodynamic turbulence in molecular clouds, and demonstrate that it can recover the 3D normalised density variance with ~10% accuracy if the assumption of isotropy is valid. We show that the assumption of isotropy breaks down at low sonic Mach number if the turbulence is sub-Alfvenic. Theoretical predictions suggest that the 3D density variance should increase proportionally to the square of the Mach number of the turbulence. Application of our method will allow this prediction to be tested observationally and therefore constrain a large body of analytic models of star formation that rely on it.Comment: 8 pages, 9 figures, accepted for publication in MNRA

Evolution of spin correlations in SrDy2O4 in an applied magnetic field

The development of short- and long-range magnetic order induced in a frustrated zig-zag ladder compound SrDy2O4 by an applied field is studied using neutron diffraction techniques. In zero field, SrDy2O4 lacks long-range magnetic order down to temperatures as low as 60 mK, and the observed powder neutron diffraction (PND) patterns are dominated by very broad diffuse scattering peaks. Single crystal neutron diffraction reveals that the zero-field magnetic structure consists of a collection of antiferromagnetic chains running along the c axis and that there is very little correlation between the chains in the ab plane. In an applied magnetic field, the broad diffuse scattering features in PND are gradually replaced by much sharper peaks, however, the pattern remains rather complex, reflecting the highly anisotropic nature of SrDy2O4. Single crystal neutron diffraction shows that a moderate field applied along the b axis induces an up-up-down magnetic order associated with a 1/3-magnetisation plateau, in which magnetic correlation length in the ab plane is significantly increased, but it nevertheless remains finite. The resolution limited k = 0 peaks associated with a ferromagnetic arrangement appear in powder and single crystal neutron diffraction patterns in fields of 2.5 T and above.Comment: 10 pages, 11 figure

Warm HCN, C2H2, and CO in the disk of GV Tau

We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN nu_3 and weak C2H2 (nu_3 and nu_2 + (nu_4 + nu_5)^0_+) absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO ~0.6% and C2H2/CO ~1.2% and an upper limit for CH4/CO < 0.37% toward GV Tau S. Neither HCN nor C2H2 were detected toward the infrared companion and results suggest that abundances may differ between the two sources.Comment: 23 pages, 6 figures, accepted by Ap

Mastering the struggle : gender, actors and agrarian change in a Mexican ejido

Actors and the Socio-Political and Symbolic OrderIn this thesis I have shown how women and men, all part of a small ejido in Western Mexico, are actively engaged in struggling to manage the social constraints and conditions they encounter. We have seen that coping with the process of agricultural change and the incorporation of the village and farm enterprise into the wider economic, political and institutional environment requires new skills and knowledge. Male and female farmers are differently engaged in this process: while men develop informal ways of dealing with representatives of the wider world, women tend to interact with them more formally. Furthermore, the actions and interactions of men and women influence the specific materializations and meanings that general processes, such as modernization of agriculture and incorporation, assume within the ejido, within the households and within the lives of different women and men. In this sense, men and women make their own history.However it is important to acknowledge that people are constrained in the choices they make. They are confronted with circumstances - material, ideological, legal as well as historical - that are beyond the scope of their influence and which exceed die particularities of the lives and the dreams of individual men and women. Normative frameworks, as organized sets of ideas often backed up by state legislation and sanctions; normative frameworks arising from shared experiences and social interaction at local level, backed up by social sanctions like gossiping, being defined as 'outsiders', etc.; and the process of uneven distribution of goods and resources, which is related to the practices of power, limit the choices social actors can make, and influence the strategies they can develop in creating room for manoeuvre. It is therefore important to localize social actors and their actions in terms of existing socio-political and symbolic frameworks.Anil Ramdas (1988), in his book The Struggle of the Dancers, uses the metaphor of a dance and its dancers to underline the tension between actors and the social order. The basic steps and the rhythm of the dance (i.e., in the context of my thesis, the socio-political and symbolic order) are defined, but the individual dancers (i.e. the social actors) have the possibility to interpret the dance according to their own character, former experiences, future expectations, and their relation to the other dancers, and thus slowly but surely to change the dance.As argued in the first chapter of this thesis, it is of little use seeking to depict a general picture of 'the' socio-political and symbolic order in Mexico, because of its fluid and non-hegemonic character. But it is relevant to describe and analyse those elements which, in specific time and place settings, enable or obstruct different social actors creating room for manoeuvre. These elements emerge from the various normative frameworks and the uneven distribution of goods and services that make up the socio-political and symbolic order. It is against this background that it becomes important to see how the relevant social actors manoeuvre, and to analyze the differences between them.Let me try to unravel here what in El Rancho the rhythm and the steps of the dance consist of, and what makes each dancer interpret the dance differently. 1 will concentrate first on the dance, i.e. the normative frameworks and the uneven distribution of goods and services, and next on the dancers, i.e. the social actors.Normative Frameworks and Uneven Distribution of Goods and ServicesSeen in historical perspective (see chapters 3 and 6), the changes brought by the process of incorporation into the wider economic and institutional environment result in a rather optimistic story as told by men, and a rather negative one from the standpoint of women. Through experience, male ejidatarios, generally regarded as heads of households by intervening parties, have been able to organize, individually and collectively, a counterforce against intervention practices that fail to take account of their specific interests. Men have generally been able to profit from new economic and social opportunities. The history of sugarcane production is a good example of this: while at the beginning of the seventies the refinery controlled the production process and set the rates of pay, nowadays the sugarcane producers, by means of two farmers' organizations (whose membership of course also includes female ejidatarias, though few hold positions of leadership), have been able to gain a degree of control over their own affairs. The success of these ejidatarios is, in large measure, due to the fact that ejido land tenure and socio-political organization have prevented a process of proletarization. Officially ejido land cannot be. sold, rented or mortgaged, though, in practice, many ways are found around these restrictions. In this particular ejido, a clear symbolic boundary was drawn between "insiders" and "outsiders", the former being ejidatarios and their sons, and the latter, women and vecinos from El Rancho itself, and those from outside El Rancho: money lenders, traders, representatives of government institutions, but also ejidatarios from neighbouring ejidos. The rules of the game differed profoundly for "insiders" as against "outsiders". Although in practice some ejidatarios lost their land, it was always to other "insiders". The socio-political organization of the ejido protected "insiders' from losing their land to outsiders, such as money lenders, notwithstanding periods of severe indebtedness and dependence. This has meant that the great majority of ejidatarios have survived to learn from their experiences with the outside world, which, because of economic and agricultural change, have become ever more important in village affairs, thus legitimizing the dominance of the world view as projected by male ejidatarios in village politics and farm household organization.Women (and here I am talking about the wives of ejidatarios) have faced a very different situation. They have not effectively been able to organize a counterforce against viricentric development practices that have ignored their interests, and in a very literal sense, they have been cut off from their original sources of income. In designing and building the new village, which brought men into contact as never before with the wider institutional environment, no account was taken, either by local government or by the ejidatarios themselves, of the economic importance of the solar for the continuity of the household and as a source of independence for women. In the new settlement, women could no longer keep small livestock, grow vegetables, pick fruits from their own trees, all of which gave them some income independent of their husbands. The loss of their solares and the further loss of control over produce, such as maize and beans, meant, with the changeover to commercial crops such as melon and sugarcane, a reduction of women's economic space and room for manoeuvre. They had some socially-recognized control over these crops when stored at home but none over the money paid to their husbands for the sale of commercial crops.It is precisely when outside involvement in ejidal and farm affairs increases that women's room for manoeuvre decreases. Previously both men and women used to work on the land but with agricultural modernization it was the men who gained the necessary knowledge and experience to find their way through the institutional environment m order to become commercial farmers, whilst women became marginal to the farm enterprise. Fruit and vegetable growing on a large-scale did offer women new opportunities in agriculture, but at the same time it brought many conflicts between men and women. The changes in the perception of a woman's position that export agriculture entailed caused women working on the melon fields to experience many problems, to such an extent that melon production in the end reinforced the ideology that women should stay at home. This became even more obvious when sugarcane came along. This is almost exclusively a "male crop", and nowadays women work rarely on die land anymore. Agricultural modernization has therefore led to men becoming defined as heads of household, and women as housewives, dependent on the income of their husbands, though in everyday life this ideal is contradicted by the necessity of many women to earn cash m petty trade and low-paid work at home. Moreover, it is precisely because of the changed definition of their primary function that women can be underpaid: their contribution is considered as an addition to the breadwinners salary, but actually vital for daily survival.These, then, are the long-term developments. Three normative frameworks seem to have influenced and guided specific developments in El Rancho. The first concerns the distinction between "insiders" and "outsiders". Those defined by the political core of the ejido as outsiders, must play a game with rules and regulations other than those defined as insiders. As we have seen, the division between insiders and outsiders does not coincide with the division between inhabitants of El Rancho and non- inhabitants: wives of ejidatarios, and men and women vecinos, all of them El Rancho inhabitants, are defined as outsiders and have little influence and few rights within the ejido. So too of course are the representatives of the state so perceived. They are not to be trusted and should be fleeced for as much as possible.The second normative framework relates to gender. According to mainstream gender ideology, women are trouble makers: the idea is that if they are not supervised by men, i.e. their fathers, husbands or brothers, they will get involved in affairs and be a disgrace to the family. They should stay at home, and if they have to leave their houses for domestic chores or work in the fields out of economic necessity, then they should do so only with permission, and preferably under the escort of male relatives. It is the men who should take care of the contacts with the world outside the household, and who should provide women with the necessities of life. Often of course, as we have seen in the thesis, practice is very different, and may lead to men using physical and mental violence against women, and to women mobilizing the solidarity and support of their children.The third normative framework revolves around verticalism and leverage. Among both men and women there exists the widespread belief that, in order to get things done, one needs the support of "influential friends% This belief is built upon previous experience and on an interpretation of how Mexican politics work. Although such political friends are not equally accessible to everybody - the dynamic of building up social networks and maintaining relations with influential men is influenced by both gender ideology and practices, and the symbolic boundaries between "insiders' and "outsiders" -, and although there are also many experiences of people being let down by their influential friends, verticalism and leverage continue to be very important in individual and collective strategies of men and women coping with the changing environment.These normative frameworks are accompanied by and influence the production and reproduction of an uneven distribution of goods and services in El Rancho. It is "male insiders" (i.e. male ejidatarios and their sons) who monopolize the front stage with regard to decision making, and who represent the village with regard to outside institutions. Hence it is them who have the best possibilities for constructing friendly ties with influential men, and for influencing public decision-making in accordance with their world views and interests. Ile monopolization of the front stage by "male insiders" has resulted, for example, in the fact that the opinions and the wishes of the women in the matter of the construction of the new village were never voiced or heard. As we have seen, this has had far reaching consequences for the everyday lives of women, and for the practical construction of gender relations. Another example concerns those defined as outsiders who stood no chance in the distribution of the new extension of the land which the ejido was expecting to be granted. However, it should be noted that over the years some fundamental changes have taken place, which have diminished the power of the political core of the ejido. First, the plots of the individual ejidatarios are nowadays well defined and hardly subject to discussion anymore, and second, since governmeat and other institutions have become so overwhelmingly present in the village, the political core cannot monopolize the contacts with the outside world anymore. It is mainly in general ejido or community affairs that they still are very important, but their influence on the development of individual farms or other enterprises is quite small.Thus far the dance: the normative frameworks and the unequal distribution of goods and services. I now turn to the dancers: the social actors.Social Actors Creating Room for ManoeuvreAgainst the above background, it becomes important to see how the social actors move. In the history chapter (6) we have already pointed to the existence of marked differences between how different men and women cope with the changing environment. These differences were explained by focussing attention on the life cycle, household composition, social networks, and the means of production. Other chapters explore further these differences by focussing on the experiences of different social actors attempting to achieve specific goals: men and women trying to get legal and actual access to land (chapters 3 and 4), a group of male farmers securing as much independence as they can in the management of their farms, notwithstanding the rules and regulations which the banks impose on them (chapter 7), and female farmers trying to assure themselves of male support in order to cope with daily farm management problems, without losing control over their land (chapter 8). These chapters reveal the actual dynamics in which the actors, men and women, are moving.From the different case studies of individuals and groups it becomes clear that in practice there exist a wide variety of ways of coping with the normative frameworks and the unequal distribution of goods and services. Let me now summarize briefly the salient points from the different chapters in order to analyse the similarities and differences that arise between the various categories of women and men.Comparing men and women in their struggles for land (chapters 3 and 4), we see several similarities. For men as well as for women, the whole issue of access to land is firmly embedded in vertical relations and leverage practices. When we look at the interactions between representatives of the ejido and the state (all men), we see that, in order to influence public decision-making, ejidatarios opt to rely on one or two people to find their way through the jungle of rules and regulations. And the same is true for individual ejidatarios, men and women, within the ejido: they rely heavily on friendship ties with Don Alfonso in order to influence decisions within the ejido to their advantage. On both levels this turns out to be a risky strategy: leverage in the state institutions in the end lets the ejido down, and when Don Alfonso dies, those who had invested time and money in their relationships with him are suddenly left with nothing. Moreover, in general it is risky to place your bets on vertical relationships, since this can undermine the horizontal solidarity and local organization which is necessary for building up sufficient pressure from below to ensure that the representatives of state institutions continue to work in one's favour on the case.Let us now turn to the differences. First, there exist marked differences in the strategies of insiders and outsiders. It is male outsiders - three vecinos and one man from a neighbouring village - who hope, by supporting Don Alfonso financially, to assure themselves of his political support. Those who live in El Rancho are not able to extract a receipt from Don Alfonso: they move on the edge of being outsiders and becoming insiders, and cannot risk loosing Don Alfonso's sympathy by showing a lack of trust. On the other hand, the man from the neighbouring village is without doubt an outsider, and thus is able to maintain a more formal relation with Don Alfonso: he obtains a written contract, signed by Alfonso. Later on this turns out to be his salvation: while the ejidatarios deny the claims of the vecinos , they have to respect the contract. The male insiders, the ejidatarios themselves, also develop strategies to assure themselves of Don Alfonso's political support. However they do not invest their own money. They allow Don Alfonso to use ejidal funds, never publically show their doubts, and are willing to participate in the occupation of the land. It is only when it becomes clear that Don Alfonso has a list of possible beneficiaries in his mind, that opposition is publically voiced and they begin to stop supporting Don Alfonso.Second, it turns out that women in general constitute a special category of outsiders, and female vecinas in particular. The latter see no possibility whatsoever in building up relations with Don Alfonso. Due to mainstream gender ideology and practices, and from the perspective of the male world, they are considered absolute outsiders. The symbolic boundaries drawn up by the influential men in the ejido, the viricentric practices of decision making, the threat of physical violence, and the lack of an accepted discourse upon which vecinas can establish the legitimacy of their wishes, are obstacles that are almost impossible to overcome. The only woman who is able to get her wishes heard and accepted is Doña Lupe, and she is an ejidataria and the widow of a respected member of the ejido, and consequently is able to draw upon different social identities which make her, figuratively speaking, "less female". But also in her case the social costs are high, especially vis-à-vis other women by whom she is judged not to be a decent women. This points to the existence of a "female discourse' which carries its own sanctions.The experiences of two other female ejidatarias, whose ejidal rights are questioned by male ejidatarios, also illustrate the importance of this division between insiders and outsiders and of building networks in the ejido. Moreover, their experiences underline the fact that, within the local arena of decision making, women's perspectives have little chance of being heard, and oven less of influencing decision-making. One of the two women is eventually able to have her claims taken seriously once she has managed to bypass the local arena through organizing political pressure from above. Until now, the other woman has not succeeded in doing so, and her claims continue to have little weight in the ejido.The chapters 7 and 8 focus on the ways in which nude and female farmers cope with the problems arising from managing a farm in the context of modem agriculture (i.e. one that is highly integrated into product and labour markets, and the institutional environment). Seen against the historical development of the village, in which men have become experienced in moving within the institutional and socio-political environment, while women are situated on the sideline of agriculture, it is not surprising that the story of male farmers is quite different from that of female farmers.Chapter 7 consists of an extended case study of a livestock credit group, of whom all but one are nude farmers. The development package offered by the Agrarian Bank does not meet the individual requirements of the livestockholders, and so, individually and collectively, they look for loopholes in the system. As we have shown, the ejidatarios turn out to be very successful: they are able to outwit the two Government institutions involved in the credit programme, and in this way to create room to adapt the implementation of the programme so that it takes into account the different realities and interests of the individual livestockholders. They are able to achieve this for two reasons. First, they have a wide variety of individual and collective experiences with this Bank in particular and with government institutions in general; and are therefore perfectly aware of the fact that, when working with Banrural, it is at the point of execution of the programme where they can most influence the course of events. Second, they share a similar image of the state. A whole range of concepts, jokes and commonly-shared anecdotes exist about state institutions and their representatives which express a general lack of confidence in them. For example, the Agrarian Bank, Banrural, is called Bandidal (a bunch of thieves); and influential representatives are named cabrones (he-goats, not to be trusted, but better to have them as friends). Then there are jokes against bank employees who, on the backs of the ejidatarios, are able to accumulate enough money to afford nice cars; and jokes about their former innocence, about successful and not so successful attempts of ejidatarios to claim their rights at the refinery or at the local department of the Ministry of Agriculture, and one could list many more. These experiences and the commonly shared notions on intervening organizations make the credit group strongly unite

Modification of Projected Velocity Power Spectra by Density Inhomogeneities in Compressible Supersonic Turbulence

(Modified) The scaling of velocity fluctuation, dv, as a function of spatial scale L in molecular clouds can be measured from size-linewidth relations, principal component analysis, or line centroid variation. Differing values of the power law index of the scaling relation dv = L^(g3D) in 3D are given by these different methods: the first two give g3D=0.5, while line centroid analysis gives g3D=0. This discrepancy has previously not been fully appreciated, as the variation of projected velocity line centroid fluctuations (dv_{lc} = L^(g2D)) is indeed described, in 2D, by g2D=0.5. However, if projection smoothing is accounted for, this implies that g3D=0. We suggest that a resolution of this discrepancy can be achieved by accounting for the effect of density inhomogeneity on the observed g2D obtained from velocity line centroid analysis. Numerical simulations of compressible turbulence are used to show that the effect of density inhomogeneity statistically reverses the effect of projection smoothing in the case of driven turbulence so that velocity line centroid analysis does indeed predict that g2D=g3D=0.5. Using our numerical results we can restore consistency between line centroid analysis, principal component analysis and size-linewidth relations, and we derive g3D=0.5, corresponding to shock-dominated (Burgers) turbulence. We find that this consistency requires that molecular clouds are continually driven on large scales or are only recently formed.Comment: 28 pages total, 20 figures, accepted for publication in Ap

From top to bottom: Cell polarity in Hedgehog and Wnt trafficking.

This is the final version of the article. Available from the publisher via the DOI in this record.Spatial organization of membrane domains within cells and cells within tissues is key to the development of organisms and the maintenance of adult tissue. Cell polarization is crucial for correct cell-cell signalling, which, in turn, promotes cell differentiation and tissue patterning. However, the mechanisms linking internal cell polarity to intercellular signalling are just beginning to be unravelled. The Hedgehog (Hh) and Wnt pathways are major directors of development and their malfunction can cause severe disorders like cancer. Here we discuss parallel advances into understanding the mechanism of Hedgehog and Wnt signal dissemination and reception. We hypothesize that cell polarization of the signal-sending and signal-receiving cells is crucial for proper signal spreading and activation of the pathway and, thus, fundamental for development of multicellular organisms.SS and LB funding was provided by the University of Exeter, UK (LSI Start-up Grant awarded to SS). ACG and DSH are funded on a Young Investigator Grant (BFU2015-73609-JIN) to ACG from MINECO (Spain). DSH was also funded by a collaboration short-term EMBO fellowship. The authors would like to thank Isabel Guerrero (University of Madrid) for her respective valuable comments that helped improve the quality of the manuscript

Sequential and Spontaneous Star Formation Around the Mid-Infrared Halo HII Region KR 140

We use 2MASS and MSX infrared observations, along with new molecular line (CO) observations, to examine the distribution of young stellar objects (YSOs) in the molecular cloud surrounding the halo HII region KR 140 in order to determine if the ongoing star-formation activity in this region is dominated by sequential star formation within the photodissociation region (PDR) surrounding the HII region. We find that KR 140 has an extensive population of YSOs that have spontaneously formed due to processes not related to the expansion of the HII region. Much of the YSO population in the molecular cloud is concentrated along a dense filamentary molecular structure, traced by C18O, that has not been erased by the formation of the exciting O star. Some of the previously observed submillimetre clumps surrounding the HII region are shown to be sites of recent intermediate and low-mass star formation while other massive starless clumps clearly associated with the PDR may be the next sites of sequential star formation.Comment: Accepted for publication in MNRAS, 8 pages, 10 figure

Photodetachment study of He^- quartet resonances below the He(n=3) thresholds

The photodetachment cross section of He^- has been measured in the photon energy range 2.9 eV to 3.3 eV in order to investigate doubly excited states. Measurements were made channel specific by selectively detecting the residual He atoms left in a particular excited state following detachment. Three Feshbach resonances were found in the He(1s2p ^3P)+e^-(epsilon p) partial cross section: a ^4S resonance below the He(1s3s ^3S) threshold and two ^4P resonances below the He(1s3p ^3P) threshold. The measured energies of these doubly excited states are 2.959260(6) eV, 3.072(7) eV and 3.26487(4) eV. The corresponding widths are found to be 0.20(2) meV, 50(5) meV and 0.61(5) meV. The measured energies agree well with recent theoretical predictions for the 1s3s4s ^4S, 1s3p^2 ^4P and 1s3p4p ^4P states, respectively, but the widths deviate noticeably from calculations for 1s3p^2 ^4P and 1s3p4p ^4P states.Comment: 10 pages, 3 figures, LaTeX2e scrartcl, amsmath. Accepted by Journal of Physics B; minor changes after referee repor

Spitzer observations of the Massive star forming complex S254-S258: structure and evolution

We present Spitzer-IRAC, NOAO 2.1meter-Flamingos, Keck-NIRC, and FCRAO-SEQUOIA observations of the massive star forming complex S254-S258, covering an area of 25x20 arc-minutes. Using a combination of the IRAC and NIR data, we identify and classify the young stellar objects (YSO) in the complex. We detect 510 sources with near or mid IR-excess, and we classify 87 Class I, and 165 Class II sources. The YSO are found in clusters surrounded by isolated YSO in a low-density distributed population. The ratio of clustered to total YSO is 0.8. We identify six new clusters in the complex. One of them, G192.63-00, is located around the ionizing star of the HII region S255. We hypothesize that the ionizing star of S255 was formed in this cluster. We also detect a southern component of the cluster in HII region S256. The cluster G192.54-0.15, located inside HII region S254 has a VLSR of 17 km/s with respect to the main cloud, and we conclude that it is located in the background of the complex. The structure of the molecular cloud is examined using 12CO and 13CO, as well as a near-IR extinction map. The main body of the molecular cloud has VLSR between 5 and 9 km/s. The arc-shaped structure of the molecular cloud, following the border of the HII regions, and the high column density in the border of the HII regions support the idea that the material has been swept up by the expansion of the HII regions.Comment: Accepted for publication in The Astrophysical Journa

Expression of GP73, A Resident Golgi Membrane Protein, in Viral and Nonviral Liver Disease

GP73 is a novel type II Golgi membrane protein of unknown function that is expressed in the hepatocytes of patients with adult giant-cell hepatitis (Gene 2000;249:53-65). Its expression pattern in human liver disease and the regulation of its expression in hepatocytes have not been systematically studied. The aims of the present study were to compare GP73 protein levels in viral and nonviral human liver disease and in normal livers, to identify its cellular sources, and to study the regulation of its expression in hepatoma cells in vitro. GP73 protein levels were quantitated in explant livers of patients with well-defined disease etiologies and compared with the levels in normal donor livers. GP73-expressing cells were identified immunohistochemically. GP73 expression in vitro was studied by Western blotting and immunofluorescence microscopy in HepG2 and SK-Hep-1 cells and in the HepG2-derived, hepatitis B virus (HBV)-transfected HepG2215 and HepG2T14.1 cell lines. Whole organ levels of GP73 were low in normal livers. Significant increases were found in liver disease due to viral causes (HBV, HCV) or nonviral causes (alcohol-induced liver disease, autoimmune hepatitis). In normal livers, GP73 was constitutively expressed by biliary epithelial cells but not by hepatocytes. Hepatocyte expression of GP73 was dramatically up-regulated in diseased livers, regardless of the etiology, whereas biliary epithelial cell expression did not change appreciably. GP73 was present at high levels in HepG2215 cells (a cell line that supports active HBV replication), but was absent in HepG2T14.1 cells (an HBV-transfected cell line that does not support HBV replication) and in HBV-free HepG2 cells. In SK-Hep-1 cells, GP73 expression was increased in response to interferon gamma (IFN-y), and inhibited by tumor necrosis factor x (TNF-x). In conclusion, increased expression of GP73 in hepatocytes appears to be a general feature of advanced liver disease, and may be regulated via distinct pathways that involve hepatotropic viruses or cytokines