bluuebunny/crossref_metadata_2025 huggingface dataset:
The Geography of Trade and Technology Shocks in the United States
Authors: Autor David H , Dorn David , Hanson Gordon H
Published: May 2013

This paper explores the geographic overlap of trade and technology shocks across local labor markets in the United States. Regional exposure to technological change, as measured by specialization in routine task-intensive production and clerical occupations, is largely uncorrelated with regional exposure to trade competition from China. While the impacts of technology are dispersed throughout the United States, the impacts of trade tend to be more geographically concentrated, owing in part to the spatial agglomeration of labor-intensive manufacturing. Our findings highlight the feasibility of separately identifying the impacts of recent changes in trade and technology on US regional economies.
Long-Term Neighborhood Effects on Low-Income Families: Evidence from Moving to Opportunity
Authors: Ludwig Jens , Duncan Greg J , Gennetian Lisa A , Katz Lawrence F , Kessler Ronald C , Kling Jeffrey R , Sanbonmatsu Lisa
Published: May 2013

We examine long-term neighborhood effects on low-income families using data from the Moving to Opportunity (MTO) randomized housing-mobility experiment. This experiment offered to some public-housing families but not to others the chance to move to less-disadvantaged neighborhoods. We show that ten to 15 years after baseline, MTO: (i) improves adult physical and mental health; (ii) has no detectable effect on economic outcomes or youth schooling or physical health; and (iii) has mixed results by gender on other youth outcomes, with girls doing better on some measures and boys doing worse. Despite the somewhat mixed pattern of impacts on traditional behavioral outcomes, MTO moves substantially improve adult subjective well-being.
Place Based Policies with Unemployment
Authors: Kline Patrick , Moretti Enrico
Published: May 2013

We develop a stylized model of frictional local labor markets with the goal of studying the efficiency of unemployment differences across areas. The model adapts the widely used Diamond-Mortensen-Pissarides framework to a local labor market setting with a competitive housing market. The result is a simple search analogue of the classic Roback model that provides a tractable environment for studying the effects of local job creation efforts.
Access to Credit by Firms in Sub-Saharan Africa: How Relevant is Gender?
Authors: Asiedu Elizabeth , Kalonda-Kanyama Isaac , Ndikumana Leonce , Nti-Addae Akwasi
Published: May 2013

The literature on the determinants of firms' financing constraints has paid little attention to gender as a determinant of access to finance. Using data for 34,342 firms from 90 developing countries, the paper analyzes the determinants of firms' financing constraints and assesses whether female-owned firms are more financially constrained than male-owned businesses. The results show that female-owned firms in sub-Saharan Africa are more likely to be financially constrained than male-owned firms, but there is no gender gap in other developing regions. The gender gap in sub-Saharan Africa is robust to variations in specifications and econometric estimation procedures.
The Informational Role of Voluntary Certification: Evidence from the Mexican Clean Industry Program
Authors: Foster Andrew D , Gutierrez Emilio
Published: May 2013

In the presence of imperfect information, voluntary certification can provide an important complement to mandatory inspections as a basis for environmental regulation in low income countries. Using data from Mexico's Clean Industry Program, we show that patterns of compliance and certification by sector are consistent with a model in which selection into the voluntary program permits more efficient targeting of regulator effort. As expected given the informational role played by certification in the model, we also find evidence, for a sample of publicly traded firms, of positive stock price deviations linked to the announcement of certification.
A Numerical Investigation of the Potential for Negative Emissions Leakage
Authors: Winchester Niven , Rausch Sebastian
Published: May 2013

Emissions restrictions in one region may decrease emissions elsewhere (negative leakage), as increased demand for capital and labor to abate emissions in constrained regions may reduce output in unconstrained regions. We investigate leakage in computable general equilibrium (CGE) models under alternative fossil fuel supply elasticity values and factor mobility assumptions. We find that fossil fuel supply elasticities must be equal or close to infinity to generate net negative leakage. As empirical estimates for fossil fuel supply elasticities are less than 1, we conclude that leakage estimates from CGE models are unlikely to be negative.
Leakage, Welfare, and Cost-Effectiveness of Carbon Policy
Authors: Baylis Kathy , Fullerton Don , Karney Daniel H
Published: May 2013

We extend the model of Fullerton, Karney, and Baylis (2012) to explore cost-effectiveness of unilateral climate policy in the presence of leakage. We ignore the welfare gain from reducing greenhouse gas emissions, and focus on the welfare cost of the emissions tax or permit scheme. Whereas that prior paper solves for changes in emissions quantities and finds that leakage may be negative, we show here that all cases with negative leakage in that model are cases where a unilateral carbon tax results in a welfare loss. With positive leakage, however, a unilateral policy can improve welfare.
Natural Gas: From Shortages to Abundance in the United States
Authors: Joskow Paul L
Published: May 2013

The history of natural gas wellhead and pipeline regulation, deregulation and regulatory reforms are discussed. These reforms brought natural gas shortages and pipeline inefficiencies to an end. They also created an economic platform that could support unanticipated developments in the supply and costs of domestic natural gas. Such unanticipated developments emerged in the last few years as several technological innovations came together to make it commercially attractive to development US shale gas deposits located deep in the earth. How and why shale gas supplies will lead to dramatic changes in the United States' energy future with appropriate environmental regulatory reforms are discussed.
Transaction Networks: Evidence from Mobile Money in Kenya
Authors: Jack William , Ray Adam , Suri Tavneet
Published: May 2013

Mobile money allows households in Kenya to spread risk more efficiently. In this paper we show that these efficiencies are achieved through deeper financial integration and expanded informal networks. Active networks are more geographically dispersed and support more reciprocal financial arrangements. Consistent with the reported reciprocity, mobile money users report a higher share of transactions as being for credit and insurance purposes.
Behavioral Biases and Firm Behavior: Evidence from Kenyan Retail Shops
Authors: Kremer Michael , Lee Jean , Robinson Jonathan , Rostapshova Olga
Published: May 2013

Many subjects in lab experiments exhibit small-stakes risk aversion, consistent with loss aversion. Those with greater math skills are less likely to show small-stakes risk aversion. We argue that departures from expected utility maximization may help explain why many firms in developing countries leave high expected return investments unexploited. We show that among a sample of Kenyan shopkeepers, inventories are negatively associated with small-stakes risk aversion and positively associated with math skills.
The Home Economics of E-Money: Velocity, Cash Management, and Discount Rates of M-Pesa Users
Authors: Mbiti Isaac , Weil David N
Published: May 2013

We study the mobile phone-based money transfer system in Kenya. Based on aggregate data, we estimate that the velocity with which units of e-money are transferred among users is approximately four times per month, and that the average number of transfers undergone by a unit of e-money between its creation and destruction is approximately one. Most M-Pesa transactions are made by frequent users. Examination of data on withdrawals shows a high frequency of small withdrawals and no response to “notches” in the price schedule, indicating that many users seem to have high implicit discount rates.
Profitability of Fertilizer: Experimental Evidence from Female Rice Farmers in Mali
Authors: Beaman Lori , Karlan Dean , Thuysbaert Bram , Udry Christopher
Published: May 2013

We conducted an experiment providing fertilizer grants to female rice farmers in Mali. We found that women who received fertilizer used both more fertilizer and more complementary inputs such as herbicides and hired labor. This shows that farmers respond to an increase in one input by re-optimizing other inputs. Second, while the increase in inputs led to a considerable increase in output, we found no evidence that profits increased. Our results suggest that fertilizer's impact on profits is small compared to other sources of variation. This may make it difficult for farmers to learn about the returns to fertilizer.
Deposit Collecting: Unbundling the Role of Frequency, Salience, and Habit Formation in Generating Savings
Authors: de Mel Suresh , McIntosh Craig , Woodruff Christopher
Published: May 2013

We report on a field experiment using several methods for collecting deposits made in formal bank accounts in rural areas in Sri Lanka. We find that only frequent, face-to-face collection increases aggregate household savings. Collection involving community lock boxes increases balances at the collecting bank, but not overall household savings. Only community box collection appears to have the possibility of being financially viable. The various collection methods allow us to unbundle the role of frequency, salience and habit formation in deposit decisions. We find that frequency and salience affect the number of transactions, but not the level of savings.
Health Care Usage and Health Status of Immigrant Children: The Effects of Nativity versus Citizenship
Authors: García-Pérez Mónica
Published: May 2013

This paper addresses the relationship between child access to and use of health services, perceived health, and parental nativity. Parental region of birth is identified to include the underlying cultural differences across immigrant groups. We found that children of immigrant families, regardless of their immigration status, have lower odds to visit the doctor at least once a year and lack of usual place of care. Conversely, this group has better outcomes with regard to their perceived health. Results hold when parental region of birth is included. Overall, non-citizen children of Latino American, Asian and African families have the worse outcomes.
Achieving the DREAM: The Effect of IRCA on Immigrant Youth Postsecondary Educational Access
Authors: Cortes Kalena E
Published: May 2013

This paper contributes to the existing literature on the effect of legal status on educational access among immigrant youth in the United States. The Immigration Reform and Control Act (IRCA) of 1986 granted amnesty to undocumented immigrants who entered the United States before 1982. Using a difference-indifferences framework, I analyze the effect of this large amnesty program on immigrant youth's postsecondary educational access. My main finding shows that immigrant youths who were granted amnesty under IRCA are more likely to enroll in postsecondary education.
Learning from Others' HIV Testing: Updating Beliefs and Responding to Risk
Authors: Godlonton Susan , Thornton Rebecca L
Published: May 2013

An individual who takes an HIV test can be informed about their own status and risk. Similarly, when friends, family or neighbors learn of a person's HIV status, they may update their beliefs about HIV infection among people they know. Using an experiment conducted in rural Malawi which randomly assigned incentives to learn HIV results, we find that as people in the community learn their HIV results, individuals revise their beliefs downward about deaths attributable to HIV/AIDS. We find corresponding behavioral responses with a significant decrease in condom use and no significant increase in multiple partnerships among those who are HIV-negative.
The Estate Tax and Inter Vivos Transfers over Time
Authors: McGarry Kathleen
Published: May 2013

The strong dislike evidenced by the American public towards the estate tax suggests that the wealthy wish to transfer resources to their heirs tax-free and would thus exploit mechanisms allowing them to reduce the tax burden whenever possible. However, I find strong evidence that the wealthy fail to utilize what is perhaps the simplest method of tax avoidance--that of making transfers to eventual heirs up to the annual exclusion. Instead they transfer far less than the amount permitted by the tax code, whether measured in cross-section or over time. In failing to give more, they forgo significant tax savings.
An Analysis of Economic Warfare
Authors: Clemens Jeffrey
Published: May 2013

I develop a framework for assessing economic warfare, which describes efforts to undermine adversaries' sources of income. The ability to target adversarial market participants is a primary determinant of the success of such efforts, as is the elasticity of demand in the relevant market. An application of the framework to US efforts to suppress the Afghan opium trade yields pessimistic results. Inelastic demand and poorly targeted enforcement have led these efforts to increase the drug trade resources flowing toward the Taliban.
Genetic Diversity and the Origins of Cultural Fragmentation
Authors: Ashraf Quamrul , Galor Oded
Published: May 2013

The origin of the uneven distribution of ethnic and cultural fragmentation across countries has been underexplored, despite the importance attributed to the effects of diversity on the stability and prosperity of nations. Building on the role of deeply-rooted biogeographical forces in comparative development, this research empirically demonstrates that genetic diversity, predominantly determined during the prehistoric “out of Africa” migration of humans, is an underlying cause of various existing manifestations of ethnolinguistic heterogeneity. Further research may revolutionize our understanding of how economic development and the composition of human capital across the globe are affected by these deeply-rooted factors.
Estimating the Effect of Salience in Wholesale and Retail Car Markets
Authors: Busse Meghan R , Lacetera Nicola , Pope Devin G , Silva-Risso Jorge , Sydnor Justin R
Published: May 2013

We investigate whether the first digit of an odometer reading is more salient to consumers than subsequent digits. We find that retail transaction prices and volumes of used vehicles drop discontinuously at 10,000-mile odometer thresholds, echoing effects found in the wholesale market by Lacetera, Pope and Sydnor (2012). Our results reveal that retail consumers devote limited attention to evaluating vehicle mileage, and that this drives effects in the wholesale market. We estimate the inattention parameter implied by the price discontinuities. In addition, our results suggest that estimating consumer-level structural parameters using data from an intermediate market can give misleading results.
Distinguishing Probability Weighting from Risk Misperceptions in Field Data
Authors: Barseghyan Levon , Molinari Francesca , O'Donoghue Ted , Teitelbaum Joshua C
Published: May 2013

We outline a strategy for distinguishing rank-dependent probability weighting from systematic risk misperceptions in field data. Our strategy relies on singling out a field environment with two key properties: (i) the objects of choice are money lotteries with more than two outcomes; and (ii) the ranking of outcomes differs across lotteries. We first present an abstract model of risky choice that elucidates the identification problem and our strategy. The model has numerous applications, including insurance choices and gambling. We then consider the application of insurance deductible choices and illustrate our strategy using simulated data.
One Essay On Dissertation Formats In Economics
Authors: Stock Wendy A , Siegfried John J
Published: May 2013

Dissertations in economics have changed dramatically over the past forty years, from primarily treatise-length books to sets of essays on related topics. We document trends in essay-style dissertations across several metrics, using data on dissertation format, PhD program characteristics, demographics, job market outcomes, and early career research productivity for two large samples of US PhDs graduating in 1996-1997 or 2001-2002. Students at higher ranked PhD programs, citizens outside the United States, and microeconomics students have been at the forefront of this trend. Economics PhD graduates who take jobs as academics are more likely to have written essay-style dissertations, while those who take government jobs are more likely to have written a treatise. Finally, most of the evidence suggests that essay-style dissertations enhance economists' early career research productivity.
How Economists Allocate Time to Teaching and Research
Authors: Allgood Sam , Walstad William B
Published: May 2013

This study investigates three questions: (i) are there differences in teaching and research behavior between economists and other professors; (ii) do economists in the top 100 research departments allocate time differently than faculty in other disciplines at similarly ranked departments; and (iii) do professors respond to changes in incentives in allocating their time? The study uses data from the National Study of Postsecondary Faculty (NSOPF). The study specifies a regression equation controlling for institutional incentives to compare time allocation to teaching and research for economics professors and faculty members in math, physics, psychology, political science and business.
The Persistence of Inferior Cultural-Institutional Conventions
Authors: Belloc Marianna , Bowles Samuel
Published: May 2013

Our theory of cultural-institutional persistence and innovation is based on uncoordinated updating of individual social norms and contracts, so that both culture and institutions co-evolve. We explain why Pareto-dominated cultural-institutional configurations may persist over long periods and how transitions nonetheless occur. In our model the exercise of elite power plays no role in either persistence or innovation, and transitions occur endogenously. This is unlike models in which elites impose inferior institutions or cultures as a self-interested distributional strategy. We show that persistence will be greater the more inferior is the Pareto-dominated configuration and the more rational and individualistic is the population.
Cyclical Variation in Labor Hours and Productivity Using the ATUS
Authors: Burda Michael C , Hamermesh Daniel S , Stewart Jay
Published: May 2013

We examine monthly variation in weekly work hours using data from 2003 to 2010. The data sources include the Current Population Survey (CPS) on hours/worker, the Current Employment Survey (CES) on hours/job, and the American Time Use Survey (ATUS) on both. The ATUS data minimize recall difficulties and constrain hours of work to accord with total available time. The ATUS hours/worker are less cyclical than the CPS series, but the hours/job are more cyclical than the CES series. We present alternative estimates of productivity based on ATUS data, and find that it is more pro-cyclical than other productivity measures.
Molecular dissection of step 2 catalysis of yeast pre-mRNA splicing investigated in a purified system
Authors: Ohrt Thomas , Odenwälder Peter , Dannenberg Julia , Prior Mira , Warkocki Zbigniew , Schmitzová Jana , Karaduman Ramazan , Gregor Ingo , Enderlein Jörg , Fabrizio Patrizia , Lührmann Reinhard
Published: May 2013

Step 2 catalysis of pre-mRNA splicing entails the excision of the intron and ligation of the 5′ and 3′ exons. The tasks of the splicing factors Prp16, Slu7, Prp18, and Prp22 in the formation of the step 2 active site of the spliceosome and in exon ligation, and the timing of their recruitment, remain poorly understood. Using a purified yeast in vitro splicing system, we show that only the DEAH-box ATPase Prp16 is required for formation of a functional step 2 active site and for exon ligation. Efficient docking of the 3′ splice site (3′SS) to the active site requires only Slu7/Prp18 but not Prp22. Spliceosome remodeling by Prp16 appears to be subtle as only the step 1 factor Cwc25 is dissociated prior to step 2 catalysis, with its release dependent on docking of the 3′SS to the active site and Prp16 action. We show by fluorescence cross-correlation spectroscopy that Slu7/Prp18 and Prp16 bind early to distinct, low-affinity binding sites on the step-1-activated B* spliceosome, which are subsequently converted into high-affinity sites. Our results shed new light on the factor requirements for step 2 catalysis and the dynamics of step 1 and 2 factors during the catalytic steps of splicing.
Seabed habitat mapping techniques: an overview of the performance of various systems
Authors: PANDIAN P.K. , RUSCOE J.P. , SHIELDS M. , SIDE J.C. , HARRIS R.E. , KERR S.A. , BULLEN C.R.
Published: May 2013

Seabed mapping has become vital for effective management of marine resources. An important role in moving towards ecosystem based management is played by the defining and understanding of the relationships among marine habitat characteristics, species distribution and human activities. Mapping seabed characteristics by means of remote acoustic sensing, using seabed seismic profiling, sidescan sonar, or echo-sounder based classification systems, is becoming of increasing importance. This paper gives a brief overview of existing marine habitat mapping technologies and their recent developments. In singlebeam echo-sounders, using multiple frequencies will be useful in classifying the seabed. It must be observed that the resolution of a sidescan sonar with narrower along-track beam width and higher range sampling rates will be better than a multi-beam echo-sounder, although the specifications of the newer systems are much improved. Airborne LIDAR bathymetry is very useful for shallow water seabed mapping, particularly in challenging rocky areas vulnerable for ship-based mapping operations. Seabed maps are essential in any case for siting of bottom mounted energy devices. The utmost care should be taken at all stages of the classification process, such as input data, control of interfering factors, seabed acoustic attributes, classification methods and ground-truth observations.
Operational numerical wind-wave model for the Black Sea
Authors: KORTCHEVA A. , KORTCHEV G. , LEFEVRE J. M.
Published: May 2013

In this paper the discrete spectral shallow water wave model named VAGBUHL1 is presented. This model is used for real-time Black Sea state forecasting. The model was verified against satellite ERS-2 altimeter wave height data.
Assessment of respiratory and ion transport potential of Penaeus japonicus gills in response to environmental pollution
Authors: ABDEL-MOHSEN H.A.
Published: May 2013

The present study aims to pinpoint the respiratory and ion transport potential of gills of Penaeus japonicus living in Abu-Qir Bay, East of Alexandria, Egypt. Our results revealed clear histological impairments in gill structure. These alterations were mainly represented by the presence of large vacuoles in gill axis and gill lamellae. In addition, narrow, disrupted gill lamellae with wavy cuticle and shrunk pillar cells were detected. Moreover, some cells clearly showed pyknosis. Gill ultrastructure also showed abnormal chromatin condensation inside the nucleus. Obvious alterations in the typical shape and structure of mitochondria were observed. Noticeably, the main characteristics of ion regulating gill epithelium were absent thus suggesting a low ion transport activity of P. japonicus gills. Statistically, this was further proved by the significantly higher activity levels of respiratory enzymes, namely, lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) compared to those of the ion transport enzymes, namely, adenosine triphosphatase (ATPase) and carbonic anhydrase (CA) in gills and haemolymph. SDH activity levels were higher than the corresponding levels of LDH in gills and its own level in haemolymph, indicating a contradictory effect of pollution on respiratory enzyme activity levels.
Poseidon: A marine environmental monitoring, forecasting and information system for the Greek seas
Authors: SOUKISSIAN T.H. , CHRONIS G.
Published: May 2013

The scope of this work is twofold: i) to discuss and analyze some principles, issues and problems related to the development and advancement of Operational Oceanography in Greece and ii) to present a real-time monitoring and forecasting system for the Aegean Sea, which is currently under implementation. Operational Oceanography in Greece has become a necessity today, since it can provide aid to find solutions on problems related to societal, economic, environmental and scientific issues. Most of the Greek coastal regions are under pressure, susceptible to damages due to the increasing tendency of the population to move from the inland to the coast, marine environmental pollution, competitive development of the coastal market sector, etc. Moreover, the complex geomorphology of the coastal areas and the interdependence between natural processes and human activities causes significant alterations in this delicate environment. A rational treatment of these problems can be based on integrated coastal zone management (ICZM). An absolutely necessary means for establishing ICZM is the operation of marine moni- toring systems. Such a system ("POSEIDON system") is under implementation by the National Centre for Marine Research. POSEIDON is a comprehensive marine monitoring and forecasting system, that aims to improve environmental surveillance and facilitate sea transport, rescue and safety of life at sea, fishing and aquaculture, protection of the marine ecosystem, etc. POSEIDON is expected to enhance considerably the capabilities to manage, protect and develop the marine resources of the Greek Seas and to promote Greek Operational Oceanography.
Practical issues in choosing a framework for resource assessment and management of Mediterranean and Black Sea fisheries
Authors: CADDY J.F.
Published: May 2013

Local context and practical constraints are important in deciding on assessment procedures for Mediterranean and Black Sea fisheries, and in formulating management measures that reflect the resource life history, fishery configuration and availability of data. A brief review of existing methods is provided, and a recommendation that practical approaches need to focus on developing the indicators and reference points appropriate for fisheries management decisions. In both the Black Sea and Mediterranean Sea proper, experience suggests environmental and ecosystem concerns must be given a high priority in the assessment process.
Subtidal littering: Indirect effects on soft substratum macrofauna?
Authors: AKOUMIANAKI I. , KONTOLEFAS P. , KATSANEVAKIS S. , NICOLAIDOU A. , VERRIOPOULOS G.
Published: May 2013

Changes in macrofauna community structure, abundance and species richness were examined both before and one year after the deployment of plastic and glass bottles at littered (litter density: 16 items / 100 m2) and non-littered (control) surfaces at three unimpacted coastal areas of the western Saronikos Gulf (Greece). In parallel, LOI% at the adjacent sediments and changes in the composition of feeding types of the megaepifauna that colonized the litter were examined across treatments. Significant changes in macrofauna community structure were demonstrated between before and after littering. At only one of the sites was there detected a significant difference in macrofauna community structure between control and littered plots after littering. This difference was linked with a significant increase in the abundance of opportunistic polychaete species and LOI% levels in the sediment surface due to the entrapment of macrophytal debris within the littered surface. The study did not show a consistent direct response of macroinfauna community to litter and the associated megafauna. Unlike the megafauna attracted by litter items, soft-substratum macrofauna is less responsive to the addition of novel hard substrates in adjacent sediments. Alternatively, it could be that the impact of littering with small items triggers a macrofauna response detectable in the long-run.
Annotated records of scombroid eggs and larvae distribution in northeastern Mediterranean waters
Authors: VASSILOPOULOU V. , SIAPATIS A. , PAPACONSTANTINOU C. , CARAGITSOU E.
Published: May 2013

The distribution of eggs and larvae of scombroid fish in northeastern Greek waters were studied during the summer of three consecutive years(1992-1994) to determine spawning, time of spawning peaks, and the possible preferred spawning grounds. Among eggs only those of Xiphias gladius were successfully identified. Larvae of Thunnus alalunga, Euthynnus alleteratus, X. gladius and Auxis rochei were recorded, the latter species being encountered more frequently than the rest. Most scombroid larvae were collected in the Sporades Islands’ basin and their abundance, particularly that of A. rochei, was relatively increased at the end of the summer, possibly suggesting increased spawning activities during that period.
First occurrence of the Indo-Pacific polychaete species Glycinde bonhourei Gravier, 1904 in the Hellenic seas (Northern Evvoikos Gulf)
Authors: SIMBOURA N.
Published: May 2013

A specimen of Glycinde bonhourei Gravier, 1904, an Indo-Pacific species, was found at a station near the metalliferous waste disposal in the Northern Evvoikos Gulf (Aegean Sea, eastern Mediterranean). This is the second report of this species in the Mediterranean Sea after its first finding in the Levantine basin (Israel and Egypt). This paper provides new information on its distributional range in the Mediterranean Sea.
Identification of the self-purification stretches of the Pinios River, Central Greece
Authors: CHATZINIKOLAOU Y. , LAZARIDOU M.
Published: May 2013

The Pinios River basin in Thessaly, Greece, is intensively farmed and heavily polluted with poorly treated domestic and industrial waste. The river was divided into 35 homogenous stretches. We investigated the self-purification capacity along the different stretches of the Pinios based on the responses of the benthic macroinvertebrate community to municipal, industrial and agricultural pollution in the basin. Water quality was assessed by the performance of six diversity and biotic indices and scores for assessing water quality. Self-purification found by the downstream amelioration of water quality was evident at five stretches. These stretches should be safeguarded and priority should be given to restoration projects along the most water-quality-degraded stretches that lack the capacity for self-purification.
A new alien species in the Mediterranean? On the presence of Sirpus monodi Gordon, 1953 (Brachyura, Pirimelidae) in Greece
Authors: PANCUCCI-PAPADOPOULOU M.A. , NALETAKI M.
Published: May 2013

Sirpus monodi, first described from West Africa (Dakar, Senegal) and later reported from Mauritania and Congo, has now been found in the eastern Mediterranean. This work reports on its occurrence in two Greek localities.
First recording of the non-native species Beroe ovata Mayer 1912 in the Aegean Sea
Authors: SHIGANOVA T.A. , CHRISTOU E.D. , SIOKOU I.
Published: May 2013

A new alien species Beroe ovata Mayer 1912 was recorded in the Aegean Sea. It is most likely that this species spread on the currents from the Black Sea. Beroe ovata is also alien to the Black Sea, where it was introduced in ballast waters from the Atlantic coastal area of the northern America. The species is established in the Black Sea and has decreased the population of another invaderMnemiopsis leidyi, which has favoured the recovery of the Black Sea ecosystem.We compare a new 1 species with the native species fam. Beroidae from the Mediterranean and predict its role in the ecosystem of the Aegean Sea using the Black Sea experience.
Application of the bentix index in assessing ecological quality of hard substrata: a case study from the Bosphorus Strait, Turkey
Authors: KALKAN E. , KARHAN S.U. , MUTLU E. , SIMBOURA N. , BEKOLET M.
Published: May 2013

In this paper, a biotic index (Bentix) has been used for the assessment of ecological quality status of shallow water hard substrate benthic ecosystems affected by coastal sewage discharges in the Bosphorus Strait. A significant difference was observed between the control and the discharge stations with regard to Bentix values (Mann-Whitney U Test, p=0.002) and ecological quality status of the discharge stations was worse than that of controls. The index values revealed that sewage discharges caused serious disturbance in macrozoobenthic communities in the area investigated. Although so far it has been used for soft bottom communities, Bentix (with some species scoring modifications) also appeared to work successfully in hard substrates, at least for the present study.
Accumulation and distribution of heavy metals in surface sediments of a semienclosed basin in the southeastern Mediterranean Sea, Egypt
Authors: ABDALLAH M.A.M.
Published: May 2013

The distribution, enrichment and accumulation of heavy metals in the surficial sediments of the Alexandria City Eastern Harbour (Mediterranean coast of Egypt) were investigated. Surface sediments (in the <63mm fraction) collected from 12 sites representing the entire area of the harbour, were analyzed by AAS for Cd, Cu, Zn, Cr, Pb and Al. Metal contents were compared with literature data to assess the pollution status of sediments. Enrichment factors (EFs) and the geoaccumulation Index (Igeo) were calculated as a criterion of possible contamination.
Allochthonous and vagrant ichthyofauna in Hellenic marine and estuarine waters
Authors: CORSINI-FOKA M. , ECONOMIDIS P.S.
Published: May 2013

A review of the non-indigenous ichthyofauna occurring in the Hellenic marine and estuarine waters is presented, including Atlantic origin colonizers, aquaculture introduced and Lessepsian alien species. 34 non-native species have been registered. The majority of allochthonous fish are Lessepsian immigrants, which represent approximately 80% of the ascertained non-native ichthyofauna in Hellenic waters; their establishment, spread, habitat, abundance and interaction with indigenous fish are discussed.
The freshwater ichthyofauna of Greece - an update based on a hydrographic basin survey
Authors: ECONOMOU A.N. , GIAKOUMI S. , VARDAKAS L. , BARBIERI R. , STOUMBOUDI M.ΤΗ. , ZOGARIS S.
Published: May 2013

Distribution records (historical, contemporary) for native and non-native freshwater fish species from 105 hydrographic basin areas were compiled and analysed in order to develop a nation-wide inventory (including transboundary river basins). Overall, 162 species, including diadromous and euryhaline, with documented occurrence records in freshwaters, and taxa of unclarified taxonomic status, are accommodated in the distributional compilation. An annotated checklist summarises the confirmed ichthyofauna of Greek freshwaters (161 species); a provisional supplementary list contains species recorded in brackish waters (55 species). In comparison to the last published (1991) checklist of freshwater fish of Greece, the present checklist shows an increase in species number of 53% (56 species). This increase has resulted mainly from taxonomic re-evaluations of existing taxa on the basis of new information and adoption of a new systematic concept. The current trend, as reflected in recent ichthyological publications, is towards abandonment of the biological species concept (BSC) and adoption of the phylogenetic species concept (PSC) for the delineation of species boundaries. The practical implications of the change in species concept on biodiversity conservation and watershed management are discussed. An overview of the composition and characteristics of the freshwater fish fauna of Greece is provided, especially with regard to the native and introduced status of species, and the spatial patterns of species richness and endemism. This systematic inventory may assist in efforts to develop nation-wide surface water bioassessment tools within the demands of the Water Framework Directive (WFD); it may further promote biodiversity conservation and biologically-orientated fishery management approaches.
Spectroscopic studies of humic acids from subsurface sediment samples collected across the Aegean Sea
Authors: SAKELLARIADOU F.
Published: May 2013

Natural humic acids are biogenic, structurally complex and heterogeneous, refractory, acidic, yellow-to black-coloured organic polyelectrolytes of relatively high molecular weight. They occur in all soils, sediments, fresh waters, and seawaters. Humic acids represent the largest portion of nonliving soil organic matter. In the present paper, humic substances were isolated from marine subsurface sediment samples collected across the Aegean sea (in Greece) and especially from a marine area extending northwards of the Samothraki plateau towards the north-eastern part of the island of Crete. In a following step, humic preparations were studied using infrared and fluorescence spectroscopy (emission, excitation and synchronous-scan excitation spectra were obtained). The infrared spectra suggested functional chemical groups such as as OH-, C-H aliphatic, C=C, C=O/COO-, salts of carboxylic acids, and also, in some cases, silicate anions or C-O from alcohols, esters and ethers. Fluorescence emission, excitation and synchronous scan excitation provided some valuable information concerning a probable origin (marine and/or terrestrial) for the isolated humics.
Alien Marine Species in the Mediterranean - the 100 ‘Worst Invasives’ and their Impact
Authors: STREFTARIS N. , ZENETOS A.
Published: May 2013

A number of marine alien species have been described as invasive or locally invasive in the Mediterranean because of their proliferation, and/or their geographical spread and/or impact on native populations. Based on that information and on the documented impact they have on the biodiversity and socioeconomics of the basin, a preliminary list of the 100 ‘worst’ Invasive Alien Species (IAS) in the Mediterranean has been produced and presented in this work along with details on their impact. Emphasis is given to their impact on socioeconomics (fi sheries/aquaculture, health & sanitation, infrastructure & building), documented for 43 species. Such selection of the ‘worst’ IAS was diffi cult and controversial and is expected to attract much attention and scientifi c criticism since not only can the documentation of the impact of IAS be controversial, but also their inventory can be biased towards the effort and resources devoted to the study of the impact of certain species/taxonomic groups. Thus, while marine plants (phytobenthos and phytoplankton) are fairly well studied, less attention has been paid to the impact of vertebrates and even less to invertebrates. Nevertheless, the list highlights the need for continued research on the issue (monitoring aliens and their impact for an integrated ecosystem based management approach over the entire area). The preliminary list can provide the basis for selecting indicator species within the Mediterranean and thus be the common ground to build cooperation about IAS within countries in the region.
The water circulation in Kavala Bay (North Aegean)
Authors: KARDARAS TH.
Published: May 2013

In this work an attempt is made to explain a case of the water circulation in the North Aegean shelf based on a set of oceanographic and meteorological measurements. It is argued that hydrodynamic conditions created by the meteorological fields of surface wind and pressure, force the renewal of the waters in the coastal area of Kavala Bay. It is shown that, although the mean horizontal water velocity is estimated at about 7cm/sec providing a time period of water renewal of the bay at about 4 days, the geostrophic circulation of the wider area in the North Aegean, controlled by the geometry of the local area, accelerates the water movement in the bay decreasing the time required for the renewal to less than one day.
Biological components of Greek lagoonal ecosystems: an overview
Authors: NICOLAIDOU A. , REIZOPOULOU S. , KOUTSOUBAS D. , ORFANIDIS S. , KEVREKIDIS T.
Published: May 2013

The paper summarises the available information on the main biological components – phytoplankton, zooplankton, phytobenthos, zoobenthos and fish – of Greek lagoonal ecosystems. Meiobenthos was also studied in one of the lagoons. All components show great variability both in space and time, which is attributed to the variability of environmental conditions. The most important variable influencing species distribution and diversity is the degree of communication with the sea and the nutrient load introduced through fresh water inputs. Certain new methods, which have been applied for evaluation of the ecological quality state of the lagoons, are also presented.
Morphological Variation In Atyaephyra Desmarestii (Millet, 1831) Within And Among Populations Over Its Geographical Range
Authors: ANASTASIADOU CH. , KOUKOURAS A. , MAVIDIS M. , CHARTOSIA N. , MOSTAKIM MD. , CHRISTODOULOU M. , ASLANOGLOU CH.
Published: May 2013

In order to elucidate the distinction of Atyaephyra desmarestii subspecies (A. d. desmarestii, A. d. orientalis, A. d. stankoi and A. d. mesopotamica ) and investigate their geographical distribution in Greece, the main morphological features and somatometric ratios were studied in numerous specimens collected from a dense station network of Greek fresh waters. Specimens from Belgium, Portugal, Albania and Turkey were also examined. Atyaephyra desmarestii was found in western and northern Greece while it was absent in eastern Greece , the Aegean and the Ionian islands. The comparison of the obtained data with those of the literature revealed a clearly overlapping variability of the main key morphological features among the four subspecies. The results of this study indicate that the current A. desmarestii subspecies are not valid on the basis of the used key features. There is only one very variable species with many ecophenotypes.
Microcassiope minor (Dana, 1852): a description of the first stage zoea (Crustacea: Decapoda: Brachyura: Xanthidae)
Authors: CLARK P.F. , DIONISIO M.A. , COSTA A.C.
Published: May 2013

The first stage zoea of Microcassiope minor (Dana, 1852) is described, illustrated and compared with thirteen other known Xanthinae. This comparison suggests that M. minor is closely related to another Atlantic Ocean xanthid, Nanocassiope melanodactyla (A. Milne-Edwards, 1867). Such an affinity may indicate that the genus Nanocassiope Guinot, 1967) is not a homogenous taxon.
Aspects on the seasonal dynamics and the vertical distribution of the crustacean zooplankton community and the Dreissena polymorpha larvae in Lake Trichonis
Authors: KEHAYIAS G. , MICHALOUDI E. , BEXI A.
Published: May 2013

In Lake Trichonis 9 crustacea species and the molluscan larvae of Dreissena polymorpha were recorded during four seasonal samplings from summer 2002 to spring 2003. Mean integrated values of crustacea abundance ranged from 4.5 to 12.9 ind/L and were mainly dominated by the calanoida Eudiaptomus drieschi. The abundance values recorded, as well as the seasonal dynamics, followed the monoacmic pattern of oligotrophic lakes. However, the presence of Daphnia cucullata, a typical representative of eutrophic lakes, the decrease of the calanoida participation in the crustacea community and the succession in the cladocera community, could probably indicate a tendency towards a change of the trophic condition of Lake Trichonis.Along the vertical axis the maximum abundance of the zooplankton community was recorded in the surface 0-10 m. Mollusca larvae were present in all seasons and their highest abundance was recorded in the surface layer 0-10 m. Temperature, competition and predation seemed to be the main factors regulating vertical distribution.
Accelerated sea level rise and coastal vulnerability in the Hersonisos coastal region (Crete, Greece)
Authors: DOUKAKIS E.
Published: May 2013

The IPCC predictions for climate changes in the 21st century assess sea level rise from 5 to 10mm/year due to the Greenhouse effect. We have already entered a period of accelerated temperature and sea level rise and one of the most important impacts of these changes is the severe erosion of the coastal areas. According to Bruun rule, a sea level rise of 1cm induces a coastal retreat of (approximately) 1m in low-lying coastal areas. Taking into consideration the inundation concept, the historical retreat and the Bruun erosion model, the assessment of the coastal setback comes nearer to the response of nature due to climate changes. In the coastal region of the Hersonissos in Crete, Greece and for 21km of its shoreline, the impacts of the above models are considered in order to assess the vulnerability due to the Greenhouse effect. The results are impressive and estimate a coastal retreat of more than 280m up to the end of the century, posing a threat to the coastal infrastructure. In view of the results, decisions and measures should be considered without delay.
Grain size distribution, clay mineralogy and chemistry of bottom sediments from the outer Thermaikos Gulf, Aegean Sea, Greece
Authors: PEHLIVANOGLOU K.G. , TRONTSIOS G. , TSIRAMBIDES A.
Published: May 2013

The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite). The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K) and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K) for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral composition and signifies their terrigenous origin presenting discretely clastic character.
Copper and manganese in loggerhead turtles (Caretta caretta) tissues in the Mediterranean
Authors: ANTONIOU Z.K. , DASSENAKIS M. , PANAGOPOULOS D. , SOFOULI E.
Published: May 2013

The natural radionuclides 238U ,234Th, 40K and the main man-made 137Cs, have been studied inMytilus galloprovincialis (Lamarck, 1819) sampled in the Thermaikos gulf – North Aegean Sea, considered as a bioindicator for radiological assessment in the Mediterranean. The ratio 234U/238U has also been determined. In terms of 137Cs, the activity concentrations in seawater from the studied area have been measured as well, and the concentration factors of 137Cs in Mytilus galloprovincialis are given as a parameter of the organism response to radioactive pollution.