a b s t r a c tObjective: With the current SARS-CoV2 outbreak, countless tests need to be performed on potential symptomatic individuals, contacts and travellers. The gold standard is a quantitative polymerase chain reaction (qPCR)ebased system taking several hours to confirm positivity. For effective public health containment measures, this time span is too long. We therefore evaluated a rapid test in a highprevalence community setting. Study design: Thirty-nine randomly selected individuals at a COVID-19 screening centre were simultaneously tested via qPCR and a rapid test. Ten previously diagnosed individuals with known SARS-CoV-2 infection were also analysed. Methods: The evaluated rapid test is an IgG/IgMebased test for SARS-CoV-2 with a time to result of 20 min. Two drops of blood are needed for the test performance. Results: Of 49 individuals, 22 tested positive by repeated qPCR. In contrast, the rapid test detected only eight of those positive correctly (sensitivity: 36.4%). Of the 27 qPCR-negative individuals, 24 were detected correctly (specificity: 88.9%). Conclusion: Given the low sensitivity, we recommend not to rely on an antibody-based rapid test for public health measures such as community screenings.

The global expansion of urban slums poses questions for economic research as well as problems for policymakers. We provide evidence that the type of poverty observed in contemporary slums of the developing world is characteristic of that described in the literature on poverty traps. We document how human capital threshold effects, investment inertia, and a “policy trap” may prevent slum dwellers from seizing economic opportunities offered by geographic proximity to the city. We test the assumptions of another theory—that slums are a just transitory phenomenon characteristic of fastgrowing economies—by examining the relationship between economic growth, urban growth, and slum growth in the developing world, and whether standards of living of slum dwellers are improving over time, both within slums and across generations. Finally, we discuss why standard policy approaches have often failed to mitigate the expansion of slums in the developing world. Our aim is to inform public debate on the essential issues posed by slums in the developing world.

We provide the first experimental evidence on the effect of student loans on educational attainment. Loan amounts listed in financial aid award letters (“offers”) do not alter students’ choice sets but significantly affect borrowing. Students randomly receiving a nonzero offer were 40 percent more likely to borrow than those who received a $0 offer. Per additional borrower, loans increased by $4,000, GPA and completed credits increased by 30 percent, and transfers to four-year public colleges increased by 11 percentage points. Cost-benefit and theoretical analyses suggest nonzero offers enhance welfare, yet over five million students are not currently offered loans. (JEL D14, D91, I22, I23)

Highlights: A laboratory-based surveillance tool for SARS-CoV-2 was established  It consists of minipool testing of nucleic acid preparations  Limit of detection was 48 copies per reaction (95% confidence interval: 33 -184)  A protocol was distributed among five German university hospitals J o u r n a l P r e -p r o o f  The approach proved its principle and one COVID-19 case was detected in 70 minipools Abstract: Background: A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in China in late 2019 and subsequently caused a pandemic. Surveillance is important to better appreciate this evolving pandemic and to longitudinally monitor the effectiveness of public health measures. Objectives: We aimed to provide a rapid, easy to establish and costeffective laboratory-based surveillance tool for SARS-CoV-2. Study design: We used minipools of RNA prepared from nucleic acid extractions of routine respiratory samples. We technically validated the assay and distributed the protocol within an informal network of five German university laboratories. Results: We tested a total of 70 minipools resembling 700 samples shortly before the upsurge of cases in Germany from 17.02.2020-10.03.2020. One minipool reacted positive and after resolution one individual sample tested SARS-COV-2 positive. This sample was from a hospitalized patient not suspected of having contracted SARS-CoV-2. Conclusions: Our approach of a laboratory-based surveillance for SARSCoV-2 using minipools proved its concept is easily adaptable and resource-saving. It might assist not only public health laboratories in SARS-CoV-2 surveillance. Investigation, Formal J o u r n a l P r e -p r o o f

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Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in ABSTRACTWe estimate the effect of grant aid on poor college students' attainment and earnings using student-level administrative data from four-year public colleges in Texas. To identify these effects, we exploit a discontinuity in grant generosity as a function of family income. Eligibility for the maximum Pell Grant significantly increases degree receipt and earnings beginning four years after entry. Within 10 years, imputed taxes on eligible students' earnings gains fully recoup total government expenditures generated by initial eligibility. To clarify how these estimates relate to social welfare, we develop a general theoretical model and derive sufficient statistics for the welfare implications of changes in the price of college. Whether additional grant aid increases welfare depends on (1) net externalities from recipients' behavioral responses and (2) a direct effect of mitigating credit constraints or other frictions that inflate students' inschool marginal utility. Calibrating our model using nationally representative consumption data suggests that increasing grant aid for the average college student by $1 could generate negative externalities as high as $0.50 and still improve welfare. Applying our welfare formula and estimated direct effects to our setting and others suggests considerable welfare gains from grants that target low-income students. JEL Classification Codes AbstractWe estimate the effect of grant aid on poor college students' attainment and earnings using student-level administrative data from four-year public colleges in Texas. To identify these effects, we exploit a discontinuity in grant generosity as a function of family income. Eligibility for the maximum Pell Grant significantly increases degree receipt and earnings beginning four years after entry. Within 10 years, imputed taxes on eligible students' earnings gains fully recoup total government expenditures generated by initial eligibility. To clarify how these estimates relate to social welfare, we develop a general theoretical model and derive sufficient statistics for the welfare implications of changes in the price of college. Whether additional grant aid increases welfare depends on (1) net externalities from recipients' behavioral responses and (2) a direct effect of mitigating credit constraints or other frictions that inflate students' in-school marginal utility. Calibrating our model using nationally representative consumption data sugg...

Using unique data from one of Africa's largest informal settlements, the Kibera slum in Nairobi, we provide evidence of ethnic patronage in the determination of rental prices and investments. Slum residents pay higher rents and live in lower quality housing (measured via satellite pictures) when the landlord and the locality chief belong to the same ethnicity. Conversely, rental prices are lower, and investments higher when residents and chiefs are co-ethnics. Our identification relies on the exogenous appointment of chiefs and is supported by several tests, including a regression discontinuity design. (JEL J15, O15, O17, O18, R21, R31)

We estimate effects of the Pell Grant—the largest US federal grant for college students—using administrative data from Texas public colleges and a discontinuity in grant generosity for low-income students. Within four-year institutions, eligibility for additional grant aid significantly increases first-time students’ degree completion and later earnings. Our estimated impacts on earnings alone are enough to fully recoup government expenditures within 10 years, suggesting that financial aid likely pays for itself several times over. (JEL H75, I22, I23, I26, J24, J31)