关于大学生兼职的调查与建议

当前,大学生兼职已日益成为一种潮流和趋势,但在兼职市场并不成熟的情况下,许多大学生一不小心就落入兼职的"美丽"陷阱之中。鉴于此,针对大学生兼职这个主题,在部分高校展开了调查。通过分析统计,有针对性地提出大学生兼职预防"美丽"陷阱的建议与对策,以增强大学生自我保护的意识。     

Effekte der Gruppengröße auf die Arbeitsmarktintegration von Migranten

Some ethnic minorities tend to be less successful in the German labour market compared to the indigenous population even when controlling for relevant resources. The paper uses data from the German Mikrozensus to investigate to what extent the remaining ethnic disadvantages can be explained by relative minority group size. On theoretical grounds, ethnic concentration can have an impact on the members of the own minority as well as on members of other ethnic groups. The paper finds empirical evidence that a strong ethnic concentration impedes structural assimilation of Turkish migrants with a higher level of education, as the ethnic mobility trap model would suggest. However, the share of the Turkish population in a county does not only have an impact on the labour market performance of Turkish migrants (endogenous effect) but also affects the economic success of Italians and Germans (exogenous effects). The empirical results indicate, that controlling for regional concentration can – at least for some minority groups and to some extent – explain remaining ethnic disadvantages.     

Trying to stay ahead of the curve in Chile's economic development: exploring a way out of the middle‐income trap through pragmatic export development

Underneath impressive growth levels, the Chilean economy displays signs of being caught in a middle‐income trap. It has been unable to improve its productivity, increase the added value of its exports or upgrade its value chain. Its economy cannot compete either with low‐wage countries or highly productive, innovative countries. Its export strategy based on export promotion seems to have outlived its usefulness. It achieved remarkable quantitative success, but must now attend qualitative attributes. Instead of regarding market‐driven export promotion and state‐led export development as substitutes, this article proposes to view them as alternatives in different stages of development. To choose the appropriate time, more attention should be given to non‐traditional, structural indicators, like export sophistication and political‐institutional capabilities.     

Effects of forest structure on the distribution of southern flying squirrels (Glaucomys volans) in urban parks

Although southern flying squirrels (Glaucomys volans) are present in many urban parks, squirrel-habitat relationships in such areas are poorly understood, limiting conservation efforts. Our objective was to quantify the effects of forest structure at multiple scales on flying squirrel distribution in New York City (NYC) parks. From 18 June–24 August 2001, we captured flying squirrels in 5 New York City parks and measured forest structure at the ground, shrub, understory, and overstory levels at trap sites. To examine the importance of forest structure to squirrels, we compared (1) habitat variables between trap stations where squirrels were captured and not captured and (2) habitat variables between parks with and without documented squirrel populations. Our data suggest that areas with forests containing smaller trees at higher densities, dense woody ground cover, and little herbaceous ground vegetation may not provide the food, cavities, ease of movement, or allow predator detection necessary to be used by or support flying squirrel populations. Other factors, such as the size and density of stumps and snags may be important to non-urban squirrel populations, but not populations in NYC parks. Because NYC parks contain almost all of the remaining woodlands within the City, forests within these areas should be a conservation priority.     

RELEASING THE TRAP: A METHOD TO REDUCE INATTENTION BIAS IN SURVEY DATA WITH APPLICATION TO U.S. BEER TAXES

This study uses discrete choice experiments to explore the efficacy of prompts targeted at reducing inattention bias. Upon receiving feedback, inattentive respondents are given the opportunity to reanswer a so‐called “trap question” that checks for attentiveness. We find that individuals who miss trap questions and do not correctly revise their responses have significantly different choice patterns as compared to individuals who correctly answer the trap question. Adjusting for these inattentive responses has a substantive impact on policy impacts. Results, based on attentive participant responses, indicate that a minimum beer price would have to be substantial to substantially reduce beer demand. (JEL C83, Q18, Q51)     

未来中国经济:如何跨越“中等收入陷阱”

在全球经济危机影响下,中国经济面临外部条件恶化、国内问题凸显的考验,有关中国经济高速发展可持续性的争议引人关注。学术界对于"中等收入陷阱"的研究和分析表明,无论命题真伪,确实在一部分发展中国家的经济发展过程中,出现了"中等收入陷阱"的现象和事实。经济发展不仅仅是突破"贫困陷阱"和"人口陷阱"的问题,到一定阶段还会面临"中等收入陷阱"的挑战。中国未来5~10年是一个非常关键的发展时期,关系到是否可以顺利地跨越"中等收入陷阱",进入高收入国家行列。中国必须通过制度创新,彻底转变经济发展方式,这才是未来成功跨越"中等收入陷阱"的战略选择和必由之路。     

Why Transition Countries May Specialize in Low-Quality Production

Politicians and economists of transition countries fear a low-quality trap for their economies. We present a model of international trade with two countries and two qualities of goods model where high-quality production exhibits economies of scale and low-quality production does not. Depending on transaction costs, the low-quality good will be produced either in the low-wage economy (i.e., the transition country) only or it will not be traded at all. Regarding the high-quality good, we discuss three potential reasons why transition countries may be trapped in the production of low quality when economies of scale in production prevail: (a) international trade policy (i.e., GATT / WTO); (b) external economies due to quality uncertainty; (c) external economies due to demand effects (big push). All reasons favor incumbents over entrants and thus lead to a low-quality trap for transition economies due to the existence of incumbents located in industrialized countries.     

在国家与市场之间寻找中国社会政策改革的逻辑——“社会发展与社会政策:国际经验与中国改革”国际学术研讨会评述

综观东亚新兴经济体和欧美发达国家在社会政策领域的路径变迁,可以得出"两个转型"的基本结论,即东亚新兴经济体从单一追求经济增长逐渐向追求经济与社会平衡发展转型;欧美发达国家从倚重国家福利向倚重社会投资与国家福利平衡发展转型。这两个处于不同社会发展阶段的转型,对中国当前的社会发展和社会政策改革都有着非常重要的启示意义。中国作为具有后发优势的全球最有活力的新兴经济体,当前既需要解决经济增长与社会发展之间的失衡问题,也需要未雨绸缪,避免陷入欧美国家福利陷阱而背上沉重的财政包袱。因此,在国家与市场之间找到一条最具效率性和合理性的社会发展路径,才是符合当前中国社会政策改革的逻辑。     

Demand cross elasticity without substitutability: An experiment

We study a market in which goods are produced under low marginal costs with a poor degree of substitutability among products. In this environment we ran an experiment to explain why prices are interdependent even when preferences are independent. We compare our results to previous theoretical and laboratory experimental literature on price fairness. We find that even in the absence of interaction among subjects, price fairness/unfairness does play a major role in the decision to accept or reject a deal. Subjects tend to be more resistant to a price increase and reject a deal when the preferred product is not referenced to price increases of not substitute products, if these products are considered to be a benchmark for fair conduct. Thus demand cross elasticity can arise between products that are not substitutes. This result has important implications for antitrust policy. In delineating a market perimeter, fairness concerns suggest that products that are similar but not interchangeable should be included in the relevant antitrust market.     

Shadow employment in post-transition—Is informal employment a matter of choice or no choice in Poland?

According to a dualistic view, shadow employment may follow from two main labour market failures: (i) official market labour taxation distortions make it ineffective for some agents to engage in registered employment due to a tax wedge; or (ii) for some workers regular employment may be unattainable do to some high access costs or demand constraints, which results in seeking earning opportunities beyond the boundaries of the official labour market. Whereas in the first case revenues from unofficial employment should be higher than the corresponding official ones (tax evasion hypothesis), in the alternative explanation labour market tightness seems to be an underlying reason (market segmentation hypothesis).We use a unique data set from a survey on undeclared employment from Poland. Using propensity score matching and decomposition techniques we demonstrate that workers of shadow economy are characterised by slightly higher endowments, while their revenues are considerably lower than among matched official economy counterparts. Although unobservable heterogeneity is considerable, results are robust. Although this is not direct evidence, we believe these results point to the labour market segmentation hypothesis and endangerment with social exclusion.     

EFFICIENCY WAGES AND EQUILIBRIUM WAGES

We present a labor market model that allows as special cases a market paying equilibrium wages, one paying disequilibrium efficiency wages, and a market combining the two. Our analysis indicates that industrial wage differentials are not necessarily evidence of efficiency wages. Such differentials may be explained by differences across industries in labor performance standards or in the accuracy with which worker effort can be measured. We do find, however, that the relationship between wages and dismissals can be used to distinguish a market paying equilibrium wages from one paying efficiency wages.     

Biomass and biodiversity of nocturnal aerial insects in an Adelaide City park and implications for bats (Microchiroptera)

Temporal variation of insect communities in urban environments is poorly known and mechanisms driving these changes are unclear, as are the implications for insectivorous predators. We examined the relationships between season and nocturnal aerial insect biomass and biodiversity, and between temperature and insect biomass in the Adelaide zoological gardens from December 2005 to September 2006. We also compared the effectiveness of two insect trap types and used a bat detector to assess bat activity in relation to insect biomass. During the study, 9,939 insects from 13 orders were collected at the Adelaide zoo with a Malaise trap and a light trap. Mass and diversity of insects were highest during warm months, as was bat activity, and bat activity was positively correlated with insect biomass. Winter-active insects consisted predominantly of Diptera and Lepidoptera, which may provide an important winter food resource for insectivorous bats. The Malaise trap attracted fewer insect orders and biomass than did the light trap, and insects congregated within 6 m of artificial lights, so bats that forage at lights may have an advantage in urban areas. A strong need for the inclusion of urban insects to biodiversity inventories exists in the context of bat conservation.     

MARKET POWER AND COLLUSION IN THE OCEAN SHIPPING INDUSTRY: IS A BIGGER CARTEL A BETTER CARTEL?

The regulatory structure of the ocean shipping industry allows carriers to enter into joint pricing agreements (conference agreements) that are free from antitrust scrutiny, and requires freight rates to be published and policed by a government agency. We test whether this regulatory structure leads to the exercise of market power, and identify whether that market power resides with conferences themselves or requires the participation of carriers outside the conference. The results suggest that liner conferences are not particularly effective cartels although some market power may exist in ocean shipping. Market concentration may be a contributing factor to this market power. (JEL L12, L43, L92, K21)     

Heterogeneity Among Potential Foster Carers: An Investigation of Reasons for Not Foster Caring

Abstract

Although Australia is experiencing a shortage of foster carers, there is currently little understanding of why people do not become carers. This study explores the reasons given for not fostering though a survey of 897 non carers. Results indicate that, at the aggregate level, people do not become carers because they do not know anything about fostering, or because they are busy with their own children, work, or commitments to family and friends. However, if we account for heterogeneity, differences in these barriers are observed for subgroups within the sample. We investigate the structure of the market of potential foster carers by segmenting the market using cultural background as the segmentation base. Results indicate that the reasons for not fostering differ depending on the subgroup being examined. Theoretically, this suggests that heterogeneity exists within the foster care market, and that examining barriers to foster care only at the aggregate level neglects the importance of individual subsegment characteristics. Practically, results are important because they suggest that generic marketing campaigns aimed at the entire community have limited effect and that customised strategies are required to attract the particular types of carers most needed.     

The Spatial Mobility Trap? How Urban Contexts Shape the Spatial Mobility of Male Undocumented Youths

Some scholars have argued urban autonomy creates inclusive spaces for migrants, while others have argued interiorized border security and discriminatory policing constrain racialized migrants. This article examines the extent to which the urban context represents a spatial mobility trap for urban undocumented youths as they become adults, based on data from longitudinal comparative ethnography with undocumented youths, schools, and civil society actors in Paris and New York City. Public schools, public transportation, policing, and informal labor market practices distinguish the urban regimes of migrant il/legality in the two cities, shaping how such youths move within and outside urban space. These elements may magnify or mitigate legal-status distinctions between undocumented youths and others. As protections for undocumented minors waned at adulthood, New York City's regime blurred legal-status distinctions, accelerating intracity mobility for most youths while Paris's approach brightened such distinctions, limiting mobility. These findings contribute a spatial mobility perspective to studies of migrant illegality and an urban sociology perspective to the transition to adulthood.     

Amerindian Livelihoods,Outside Interventions,and Poverty Traps in the Ecuadorian Amazon

Recent efforts to explain the persistence of rural poverty have made frequent use of the concept of poverty traps, understood as self‐reinforcing poverty. The dynamic dimension of the poverty trap concept makes it a potentially useful tool for understanding conditions of persistent poverty, especially in circumstances where outside interventions “shock” the system with the intention of ending poverty and disadvantage. This article describes one such effort among a populous group of lowland Amerindians, the Shuar of Ecuador's Amazon region. Three small household surveys conducted at different times during the last 25 years suggest that the Shuar, despite having obtained access to land through a combination of their own efforts and outside interventions, have become enmeshed in a natural‐resource‐degrading poverty trap. Mestizos with land in the same region avoided this trap only by emigrating in large numbers. Secure access to land did not prevent the emergence of a poverty trap among the Shuar in large part because smallholders in Latin America faced difficult macrosociological and ecological conditions during the last decades of the twentieth century.     

Arbeitslosigkeit und ehrenamtliche Tätigkeit im Zeitverlauf

Starting point of the article is the discussion about possibilities to defuse the crisis on the German labor market by supporting volunteer work. Therefore, the effects of unemployment on the probability to volunteer are of special interest. For this purpose, logistic regressions are estimated for the years 1992 and 1996, using longitudinal data from the West German sub-sample of the German Socioeconomic-Panel (GSOEP). There is no evidence for an increasing propensity of take up or maintain volunteer work among the unemployed. In contrast, it is shown that the chance to volunteer especially in creases with a higher educational degree or if the person lives in ?secure’ family circumstances. On the ?volunteer market’ similar qualifications are in demand, which also support a successful participation in the regular labour market. Therefore, the hope an assumed in dividually higher willingness to volunteer among the unemployed may contribute to cope with the general labour market crisis turns out to be misleading. Especially low-educated persons, being a problem group on the labour market, do not look at volunteering as an adequate activity for themselves.     

BILATERAL OLIGOPOLY IN POLLUTION PERMIT MARKETS: EXPERIMENTAL EVIDENCE

We experimentally investigate behavior in a bilateral oligopoly using a supply function equilibria model discussed by Klemperer and Meyer (1989), Hendricks and McAfee (2010), and Malueg and Yates (2009). We focus on the role that market size and the degree of firm heterogeneity have on the market equilibrium. Our results indicate that subjects within the experiment recognize the strategic incentives in a bilateral oligopoly, but they do not exploit these incentives to the exact magnitude predicted by theory. We find weaker support for predicted market outcomes, as market efficiency does not depend on market size, and in some cases buyers or sellers are more successful at extracting the rents from the market. (JEL L13, Q5, C9)     

The independent’s edge in an illegal drug distribution setting: Levitt and Venkatesh revisited

Popular imagery and scholarly research have differed significantly in their perceptions and understanding of the structure and scope of organized crime and gang settings. While the common image is that of the corporate-like or formal criminal organization, past research has been more likely to argue and demonstrate in favour of market and network flexibility. In this study, we pursue this latter line of inquiry by demonstrating the market and network features that shape illegal drug distribution settings. In doing so, we rely on the Quebec Hells Angels accounting books for a one-year period, which brings us within the same empirical domain as Levitt and Venkatesh’s (2000) study of the Black Knights in 1990s Chicago. Our study sways from the main premise that oriented the Black Knight’s case study—namely that performance within the illegal drug distribution structure was directly tied to that organization’s rigid hierarchical structure. While the Hells Angels can be analyzed as a corporation, this does not mean that Hells Angels members are, by definition, at an advantage because of their organizational status in the illegal drug distribution setting in which some members are active. What our findings indicate is that a participant’s ability to adapt to market dynamics and take on a core network position within an illegal drug market (cocaine, in this study) matter most. Overall, we demonstrate that: 1) Quebec’s cocaine market was structured primarily around traditional market forces; 2) the transaction network around the Hells Angels was not centralized around a single person or small group of people; 3) Hells Angels members were not the most active participants; and 4) being a Hells Angels member did not increase one’s volume of transactions within the network—quite differently, core network positioning did.     

HUMAN CAPITAL PRODUCTION: LIFE-CYCLE PRODUCTION WITH DIFFERENT LEARNING TECHNOLOGIES

This paper investigates the human capital formation process when the learning situation is not neutral but is instead biased either to the market or to the production process. In the case of a production bias, human capital is more productive when generating additional human capital than when generating market activity. In the case of a market bias, the reverse holds. Implications from the model are used to explain the occurrence of different shaped earnings profiles of equal net present value as well as income profiles of unequal present value.