example could be the human endogenous retrovirus (HERV). Studies have shown that the env gene ofthe human endogenous retrovirus (HERV)-W encodes for syncytin, which is involved in human syncytiotrophoblast formation . Syncytins, which originate from different ERVs, were also found in several mammals like mice [239, 240], rabbits, Carnivores  and cows . Furthermore, recent studies reported high expression ofthe PERV-A receptor (HuPAR-2) in the villous trophoblast cells of humans. This expression is enhanced by the overexpression ofthe transcription factor activator protein (TFAP)-2γ, which is one ofthe transcription factors involved in the transcription of HuPAR-2 . PERV was not found highly expressed in pig placenta  and no syncytin-like proteins were recorded yet, which is in accordance with the absence of syncytiotrophoblast in pigs, where the fetal and maternal tissues are simply apposed and no fetal trophoblast cells fusion occurs . However, these results observed for HERV-W may explain the high PERV expression in some organs. In other words, this difference observed in PERV expression in different organs may be due also to higher susceptibility of their cells to PERV re-infection by the overexpression of PERV receptors. Furthermore, high expression in some organs related to the immune system like the spleen and lymph nodes may be due to an ongoing immune response which may activate the expression of PERVs
Xenotransplantation using porcine cells, tissues or organs may offer a potential solution for the shortage of allogeneic human organs . Pigs are the most favored donor species for several reasons: (i) similar physiology and size of organs, (ii) unlimited availability, (iii), short generation interval, high number of progeny (up to 15 to 18 piglets); (iv) relatively low costs, (v) maintenance under high hygienic conditions is possible, i.e., specified pathogen-free (spf) breeding and gnotobiotic delivery is possible, (vi) tools for the genetic modification to reduce the immunogenicity are available and (vii) somatic cloning is possible and thus production of transgenic animals can be significantly enhanced . However, prior to the clinical use ofporcine xenotransplants, three main hurdles have to be overcome: The immunological rejections, the physiological incompatibility and theriskoftransmissionofporcine pathogens. The premier immunological hurdle, the hyperacute rejection, which is due to the stimulation ofthe human complement system through the gal alpha 1,3 gal epitopes on the surface ofporcine cells can be overcome in a clinically acceptable manner by either the production of Gal knock- out animals [3,4] or animals over-expressing human complement regulatory factors .
Whereas the viruses discussed above may be eliminated by selection, treatment, vaccination, Caesarean delivery, early weaning and embryo transfer, this is impossible in the case ofporcineendogenousretroviruses (PERVs). These viruses are the result of infections with retrovi- ruses in the distant past. Retroviruses possess enzymes able to transcribe the viral RNA genome into DNA cop- ies and to integrate them into the cellular genome to form proviruses . If oocytes or sperm cells happen to become infected, these proviruses will be present in all cells ofthe developing progeny and will be inherited in the same way as all other genes. Endogenous retrovi- ruses have been found in all mammals including humans . However, in contrast to the human endogenous ret- roviruses which are mostly defective and do not produce infectious particles, many retroviruses in other species remain active. Gamma- and betaretroviruses have been found integrated into the genome of pigs [58, 59] and sequencing ofthe entire pig genome (Sus scrofa) re- vealed 212 PERV insertions in the genome . The gammaretroviruses include PERV-A and PERV-B, which are integrated into the genome of all pigs, and PERV-C, found in many (but not all) pigs. PERVs are produced as infectious virus particles and may infect human cells [61–63]. In addition, recombinants between PERV-A
While most pathogens can be eliminated by specified pathogen-free breeding, this derivation technology is not expected to affect the potential transmissionofporcineendogenousretroviruses (PERV) as they are an integral part of all pig genomes. Generally, trans-species transmissions occur in nature and result either in immunodeficiencies (e.g., human immunodeficiency viruses: HIV-1 and HIV-2) and/or tumors (e.g., feline leukemia virus, FeLV; Koala retrovirus, KoRV) . Although PERVs are able to infect several human cell types in vitro [8–12], the potential to infect humans in vivo and possibility to cause diseases remains to be established. Exploratory clinical xenotransplantation trials including ex vivo perfusion allowing short-term contact of human recipients to living porcine cells or tissues have not resulted in transmissionof PERV [13–21]. Similarly, investigations of non-human primates that had received porcine cells or organs showed no
[Bartosch et al., 2004], [Harrison et al., 2004] and [Dieckhoff et al., 2007]). PERV-A/C were also not found in the New Zealand designated pathogen-free herd (Garkavenko et al., 2008). However, there are new reports on PERV-A/C in commercially used pigs with an increased number in clinically affected animals (Pal et al., 2011). In addition, there are also other reasons not to use PERV-C positive animals. First, the ability of PERV-C to infect cells that do not harbor the specific receptor by receptor-independent infection (Lavillette and Kabat, 2004), and second, mutations in the envelope protein of PERV-C may change the tropism towards human cells (Gemeniano et al., 2006). These data indicate, that breeding out PERV-C will reduce theriskof PERV transmission in
they are produced and therefore reach the circulation ofthe organism in which they are present. Despite an enormous increase in knowledge concerning PERVs, the overall safety analysis of pigs which may be used for xenotransplantation is limited. The infectious risks caused by the presence of numerous PERVs in the pig genome and the possible impact of PERVs on the health ofthe recipient is badly studied due to the lack of an appro- priate animal model.All pigs harbour PERVs as an integral part of their genome  and PERVs are known to infect human cells in vitro [7, 8]. Although no transmissionof PERV has so far been observed in non-clinical and clinical xenotransplantation , strategies should be developed preventing virus transmission. However, there is evidence for adaptation of PERVs to human cells [15, 16] and for immunosuppressive properties [17, 18]. Because ofthe transspecies transmissionofthe human immunodeficiency viruses (HIVs) which induces fatal immunodeficiencies in the infected individuals, therisk that PERVs induce immunodeficiencies and/or tumours in the transplant recipient cannot be excluded. Furthermore, closely related retroviruses such as the murine leukaemia virus (MuLV), feline leukaemia virus (FeLV) and the Koala retrovirus (KoRV) induce tumours and immunodeficiencies in the infected hosts . Moreover, α1,3-galactosyltransferase (α1,3GT) gene knockout pigs [20–22] may present a new risk for xenotransplantation, be- cause PERV released from these animals lack α1,3-galactose residues in the viral envelope and therefore could escape the complement cascade .
Xenotransplantation has been proposed as a solution to the shortage of suitable human donors. Pigs are currently favoured as donor animals for xenotransplantationof cells, including islet cells, or organs. To reduce thexenotransplantation-associated riskof infec- tion ofthe recipient the pig donor should be carefully characterised. Göttingen minipigs from Ellegaard are often used for biomedical research and are regularly tested by their vendor for the presence of numerous bacteria, fungi, viruses and parasites. However, screening for some pathogens transmittable to humans had not been performed.The presence of micro- organisms was examined in Göttingen Minipigs by PCR methods. Since zoonotic transmis- sion ofporcine hepatitis E virus HEV to humans has been demonstrated, extended search for HEV was considered as a priority. RNA from sera, islet and other cells from 40 minipigs were examined for HEV using different real-time reverse transcription (RT)-PCRs, among them two newly established. In addition, sera were examined by Western blot analysis using two recombinant capsid proteins of HEV as antigens. HEV RNA was not detected in pigs older than one year including gilts, but it was detected in the sera of three of ten animals younger than 1 year. Furthermore, HEV was also detected in the sera of three sows six days after delivery and their offspring, indicating vertical transmissionofthe virus. PCR amplicons were cloned, sequenced and the viruses were found to belong to the HEV genotype (gt) 3/4. Anti-HEV immunoglobulins G were detected in one sow and maternal antibodies in her six day old piglet. Since Göttingen minipigs were negative for many xeno- transplantation-relevant microorganisms, they can now be classified as safe. HEV may be eliminated from the Ellegaard herd by selection of negative animals and/or by treatment ofthe animals.
Abstract: Allotransplantation and xenotransplantation may be associated with thetransmissionof pathogens from the donor to the recipient. Whereas in the case of allotransplantation the transmitted microorganisms and their pathogenic effect are well characterized, the possible influence ofporcine microorganisms on humans is mostly unknown. Porcine circoviruses (PCVs) are common in pig breeds and they belong to porcine microorganisms that still have not been fully addressed in terms of evaluating the potential riskofxenotransplantation using pig cells, tissues, and organs. Two types of PCVs are known: porcine circovirus (PCV) 1 and PCV2. Whereas PCV1 is apathogenic in pigs, PCV2 may induce severe pig diseases. Although most pigs are subclinically infected, we do not know whether this infection impairs pig transplant functionality, particularly because PCV2 is immunosuppressive. In addition, vaccination against PCV2 is able to prevent diseases, but in most cases not transmissionofthe virus. Therefore, PCV2 has to be eliminated to obtain xenotransplants from uninfected healthy animals. Although there is evidence that PCV2 does not infect—at least immunocompetent—humans, animals should be screened using sensitive methods to ensure virus elimination by selection, Cesarean delivery, vaccination, or embryo transfer.
is therisk to transmit porcine microorganisms to the recipi- ent which may induce severe disease (zoonosis or xenosis). Microorganisms include bacteria, protozoa, fungi and vi- ruses. In this context viruses are certainly the most harmful microorganisms due to the lack of effective antivirals and vaccines. Among theporcine viruses of interest are DNA viruses such as PCMV, theporcine circoviruses 1, 2 and 3 (PCV1, PCV2, PCV3), and theporcine lymphotropic herpesviruses (PLHV-1, PLHV-2, PLHV-3) as well as RNA viruses such as the hepatitis E virus (HEV), theporcine reproductive and respiratory syndrome virus (PRRSV) and the Nipah virus (NIV) (for reviews discussing each virus type in the context ofxenotransplantation see [ 18 – 25 ]). Some of these viruses, e.g. PCV2, PRRSV and NIV, cause severe disease in the infected pigs and can easily be detected. For the detection ofthe viruses not causing diseases in the infected pigs sensitive screening methods
Porcine circoviruses (PCV) belong to the genus Circovirus ofthe family Circoviridae [ 1 ]. Circoviruses are non-enveloped spherical particles with a single-stranded circular small DNA genome, they are the smallest viruses found to be replicating in mammalian cells and two types of PCV have been well characterized in the past, PCV1 and PCV2 [ 2 ]. PCV1 was isolated from a pig kidney cell culture (PK15 cells) and found to be apathogenic in pigs, whereas PCV2 was found to be associated with a complex of diseases called PCV-associated disease (PCVAD) or PCVD. Previously the most severe PCVD was called postweaning multisystemic wasting syndrome (PWMS), now called PCV2-systemic disease (PCV2-SD). In addition, PCV2 is associated with PCV2-subclinical infection (PCV2-SI), PCV2-reproductive disease (PCV2-RD), and porcine dermatitis and nephropathy syndrome (PDNS). The finding of PCV2 in subclinical infections suggests that co-factors such as co-infection with other viruses, for example porcine reproductive and respiratory syndrome virus (PRRSV), are required for the induction of diseases. Since both PCV1 and PCV2 can infect human cells [ 3 , 4 ] they may pose a risk when PCV-positive pig organs are used in xenotransplantation [ 5 ]. Organs from PCV2 infected pigs may be not fully functional even if the pig is not diseased.
Therefore, the ecological functions have not been linked in a transverse way to the prevention and reductionof ecological risks. It can be considered as a key factor for the development of planning instruments and public policies that could have a key effect on the welfare ofthe population and environmental stability, as well as thereductionof economic losses that disasters bring. Which, according to with the Convention on Biological Diversity, (2018) selecting ecosystem solutions in disaster riskreduction, are usually more adaptive and cost-effective and easier to maintain, and most importantly, it focuses in the whole suite of services that an ecosystem or landscape provides. The reason why Eco-DRR could integrate those ecological functions to address ecosystem-based approaches in the national, regional and local level. That is why urban wetlands can be taken as part ofthe management of disaster riskreduction related to flooding events. Considering that these ecosystems in the city are located close to Bogota river, and are identified in areas with a high threat of flooding, according to IDIGER's flood hazard map referred in the Resolution 1060 of 2018 of Bogota Secretariat of Planning [Secretaría Distrital de Planeación- SDP]. To do so, it is important to recognise how wetlands are or not involved in the district management scheme, for it to have a closer approach to the Eco-DRR, and more important recognised how is the current state of them through previous research over them.
In addition to these three standard variables, our fourth and fifth variables are two indicators for the banking sector. For our fourth variable, we use the banks’ lending margin, defined by the European Central Bank (ECB) as the difference between interest rates on new business loans and a weighted average interest rate on new deposits from households and non-financial corporations. This variable reflects the banking sector’s ability to generate profit in its core field of credit lending. Declining margins could trigger the aforementioned search for yield and are expected to be a key element in therisk-taking channel. The overall euro area lending margin is calculated as the weighted average of country-specific interest rate margins with the countries’ contribution to the ECB’s capital as a weighting scheme. 4 Our fifth variable is a measure of lending standards that is taken from the ECB’s bank lending survey of around 140 banks from all euro area countries. This indicator is calculated as the net percentage of banks reporting a tightening in credit standards (as opposed to an easing) in comparison to the previous quarter. The rationale behind using this variable is to measure the change of non-financial obstacles in credit lending, such as loan-to-value restrictions, collateral, or securities.
child. Additionally, I also control for contemporaneous effects such as child labor, government program benefits, state fixed effects and indicators for girls and rural areas.
Besides its appealing simplicity, the single regression approach has the advantage that we do not have to impose a lot of structure in the model. Therefore, only the standard assumptions for ordinary least squared must be fulfilled. One concern that could arise is that some variables do not satisfy these conditions and are likely to be correlated with the error term. The most likely reason for this to happen in our context is an omitted variable bias. A first critical variable is the ability level ofthe child, which might also capture for instance motivation or the ability to perform well in a situation of examination. Both potentially omitted variables are also likely to influence the schooling outcome. To a large extent, these concerns are reduced by the type of cognitive ability measure I am using in this study. The ability measure is based on a short version ofthe Raven’s progressive matrices test, which is one ofthe most culture-free and education independent IQ-tests (De´sert et al. 2009 ). I discuss this in more detail when describing the data in Sect. 4 . A second variable that might suffer an omitted variable bias is parental education, as parental education might also be influenced by preferences and taste for education. If these preferences and tastes are also transmitted to the next generation, we are likely to have an endogeneity problem as well.
such as the role of civil society and institutions in the organisation of agricultural insurance.
This short overview shows that, although there exists a variety of insurance products at the moment, many of them bear a resemblance to each other and are based on the same features or functioning principles. However, there may be considerable differences in purchase decisions and riskreduction between crop insurance products. M ISHRA and G OODWIN (2006) investigate revenue insurance 10 purchase decisions. They motivate their research on revenue insurance by citing several studies on comparative advantage of revenue insurance compared to price support programmes or pure crop yield insurance. E.g. T URVEY (1992) compared public expenditures per monetary unit (dollars in this case) ofriskreduction and found revenue insurance was the best at promoting self-insurance through diversification. Similar results were obtained by G RAY et al. (1994), H ARWOOD et al. (1994, 1999) and H ENNESSEY et al. (1997). S TOKES et al. (1997) show that insuring for the whole farm’s revenue is more efficient than insuring each crop by a different revenue insurance policy. C OBLE et al. (2000) demonstrate that revenue insurance may be a substitute for alternative riskreduction strategies, such as hedging with futures and options. M AHUL and W RIGHT (2003) indicate that revenue insurance contracts might be complementary to typical hedging instruments. However, all mentioned studies do not include weather index insurance (WII) 11 , which is a relatively new insurance instrument. The following section will compare weather index insurance to other available insurance products. A special focus lies on the applicability of insurance products under transition conditions.
Da trotz aller bislang durchgef¨ uhrten in vitro und in vivo Versuchsans¨atze zur Risiko- evaluierung der PERV Transmission kein absolute Sicherheit bei der Xenotransplantation gew¨ahrleistet werden kann, wurde in diesem zweiten Teil der Arbeit versucht, die PERV Freisetzung durch neue molekularbiologische Methoden zu inhibieren. In der Vergangen- heit war man bei dem Versuch, endogen exprimierte Proteine zu inhibieren, auf aufwen- dig durchzuf¨ uhrende Gen-Knockouts beschr¨ankt (Reviews, siehe [Mueller, 1999, Gong and Rong, 2003]) Diese genetischen Manipulation k¨onnen durchgef¨ uhrt werden, wenn das zu hemmende Gen in einfacher oder doppelter Ausf¨ uhrung im Genom lokalisiert ist. Bei den porcinen endogenen Retroviren stellt sich jedoch das Problem, dass etwa 50 unterschied- liche Integrationsorte im Genom des Schweins verankert sind [Bosch et al., 2000, Herring et al., 2001]. Obwohl viele dieser Provirus-Sequenzen mutiert oder deletiert sind und daher nicht f¨ ur die Expression intakter Viren zur Verf¨ ugung stehen, kann dennoch nicht v¨ol- lig ausgeschlossen werden, dass es durch homologe Rekombination dieser Sequenzelemente zur Komplementation intakter Virusgenome kommen kann. Andere Arbeitsgruppen ver- suchten daher durch konventionelle Zuchtmethoden Schweine heranzuziehen, die in ihrem Genom keine Variante des humanotropen PERV-A/C Subtyps enthalten [Oldmixon et al., 2002]. Diese Schweine setzen nach Angaben der Autoren keine humanotropen PERV Virio- nen frei. Allerdings konnte k¨ urzlich gezeigt werden, dass selbst porcine Zellen, die in ihrer genomischen DNA keine proviralen Sequenzen f¨ ur humanotrope replikationskompetente PERV-A/C Rekombinanten enthalten, in der Lage sind, nach Rekombination derartige Vi- rionen zu exprimieren, die dann humane Zellen infizieren k¨onnen [Scobie et al., 2004,Wood et al., 2004].
During the past decade, risk taking has emerged as a central concept for understanding economic behavior under uncertainty (e.g. Guiso and Paiella 2005; Tanaka et al., 2010; Dohmen et al., 2011; Hardweg et al., 2013). Yet, for the societal contexts most characterized by salient uncertainty, developing countries, the notion ofrisk taking has been awarded little empirical investigation. In many developing regions, formal financial services and social security are scarce or under developed, political climate is highly volatile and demographic pressure ensue a constant pressure on labor markets and infrastructure. During such harsh conditions of uncertainty about the imminent future, investments are impeded. From this follows that risk taking behavior may be of particular importance to explain economic as well as social behavior on the individual level. Previous research has looked at what individual characteristics determines risk taking in developed (Dohmen et al., 2012) and developing sub-Saharan (Sepahvand and Shahbazian 2017) countries. The findings indicate that individual characteristics such as gender, parental education, own education and age are important determinants ofrisk attitudes. However, the literature remain sparse and several gaps exist, in particular regarding the intergenerational transmissionofrisk behavior. Therefore, the aim of this paper is to provide evidence on if there exist an intergenerational and multigenerational transmissionofrisk attitudes in a developing country. And investigate if risk attitudes are gendered depending on specific risk domains.
Two versions ofthe CV survey were constructed: one version including some brief training vis-à-vis probability and risk, and the other without such training. Ideally, it would be better to train people for a longer period. However, we intend to see whether some brief training as part ofthe questionnaire makes any significant difference in the responses since such education is the most realistic kind that can be pursued. The complete CV survey was translated back to English from Bengali to ensure the exact meaning ofthe original English version. The enumerators used to conduct the survey were trained regarding therisk presentations and the CV methodology following the guidelines of conducting CV studies in developing countries (see Whittington, 1998; 2002). Following several focus groups and two pilot studies, the final CV survey was conducted during October-November 2003 among 780 rural household heads in the selected 30 villages ofthe following five districts of Bangladesh: Netrokona, Mymensingh, Manikganj, Gazipur and Narayanganj. Table 1 presents the sample statistics. >>> TABLE 1
are positive, even for the case of alcohol consumption where these are almost negligible. 10
Moreover, using the comparative statics ofthe parental socialization problem, I show that the
6 To the best of my knowledge the developmental psychology literature on socialization is mute on the veracity
of this assumption— that parents cannot or do not deviate from their optimal choices to socialize their children— rather focusing more on the mechanisms of socialization. In their review ofthe literature, Grusec and Davidov (2007) emphasize that one dimension of socialization involves behavioral and psychological control that includes rule-setting and monitoring, as well as “the use of guilt-inducing strategies, withdrawal of love, and parental intrusiveness.” This type of socialization strategy corresponds to the class ofendogenous socialization schemes I use in the model. See also the historical overview on socialization research by Maccoby (2007).
solution concepts, such as farsightedness (e.g. Breton and Keoula, 2012, Walker and Weikard, 2014).
Thus, endogenousrisk solves the puzzle of small coalitions (the Great Fish War becomes a pact). However, we find that this result is very sensitive to the assumptions implicit in the standard two-stage game. We relax the assumption that payoffs are determined in steady states by considering a transition period whereby the stock size gradually adjusts after a deviation has occurred (cf. Sakamoto, 2014). Deviators receive payoffs during this transition period (“transition payoffs”). Transition payoffs turn out to be a decisive incentive for non- cooperation. Without transition payoffs, if deviation leads to pre-emptive depletion, then the payoff of deviation is zero. With transition payoffs, the process of pre-emptively depleting provides a payoff. We find that transition payoffs motivate non-cooperation to the extent that the Grand Coalition is only stable in a two-player game, and then, only if the discount rate is sufficiently low and the stock grows sufficiently slowly. The Great Fish Pact thus returns to a Great Fish War. Overall then, the paper shows how endogenousriskof stock collapse leads to dramatic increases in the potential for cooperation but qualifies this with the important
suffer from a number of drawbacks, however, which suggest that analyzing the issue from a revealed preference perspective is a worthy exercise.
Common objections to stated measures are that the ordering and word- ing of questions, the low effort exerted on answering questions accurately, the desire of an individual to convey a certain impression, the absence of hav- ing an attitude, etc., bias the preferences reported by surveyed individuals (Bertrand and Mullainathan 2001). Furthermore, the framing of questions matters (Kahneman and Tversky 1981). Responses to hypothetical lottery questions involving a new job have been found to be driven by status quo bias (Kimball et al. 2009). A problem associated with risk attitudes on an 11-point scale - as requested in the SOEP - is that it is a qualitative mea- sure which is not ideal for comparisons ofthe degree ofrisk aversion across individuals.