The Impact of the Zika Epidemic on Women’s Reproductive Intentions and Behaviors in Brazil

This research brief reports on a focus group study that explores how and why the Zika virus affects reproductive processes in Brazil. The authors found that both reproductive intentions and behaviors changed as a result of the Zika epidemic among women from low and high socioeconomic status groups in two areas of Brazil. The authors argue that Brazilian health officials and policymakers should reduce barriers to contraceptive use, address longstanding disparities in reproductive health services that put low-income women at disproportionate risk of an unwanted pregnancy, legalize abortion, and show respect and support to women who actively pursue pregnancy during the Zika epidemic.Population Research Cente

Calculating spherical harmonics without derivatives

The derivation of spherical harmonics is the same in nearly every quantum mechanics textbook and classroom. It is found to be difficult to follow, hard to understand, and challenging to reproduce by most students. In this work, we show how one can determine spherical harmonics in a more natural way based on operators and a powerful identity called the exponential disentangling operator identity (known in quantum optics, but little used elsewhere). This new strategy follows naturally after one has introduced Dirac notation, computed the angular momentum algebra, and determined the action of the angular momentum raising and lowering operators on the simultaneous angular momentum eigenstates (under $\hat L^2$ and $\hat L_z$).Comment: 12 pages, 1 figur

Nitrate retention capacity of milldam-impacted legacy sediments and relict A horizon soils

While eutrophication is often attributed to contemporary nutrient pollution, there is growing evidence that past practices, like the accumulation of legacy sediment behind historic milldams, are also important. Given their prevalence, there is a critical need to understand how N flows through, and is retained in, legacy sediments to improve predictions and management of N transport from uplands to streams in the context of climatic variability and land-use change. Our goal was to determine how nitrate (NO3−) is cycled through the soil of a legacy-sediment-strewn stream before and after soil drying. We extracted 10.16 cm radius intact soil columns that extended 30 cm into each of the three significant soil horizons at Big Spring Run (BSR) in Lancaster, Pennsylvania: surface legacy sediment characterized by a newly developing mineral A horizon soil, mid-layer legacy sediment consisting of mineral B horizon soil and a dark, organic-rich, buried relict A horizon soil. Columns were first preincubated at field capacity and then isotopically labeled nitrate (15NO3−) was added and allowed to drain to estimate retention. The columns were then air-dried and subsequently rewet with N-free water and allowed to drain to quantify the drought-induced loss of 15NO3− from the different horizons. We found the highest initial 15N retention in the mid-layer legacy sediment (17 ± 4 %) and buried relict A soil (14 ± 3 %) horizons, with significantly lower retention in the surface legacy sediment (6 ± 1 %) horizon. As expected, rewetting dry soil resulted in 15N losses in all horizons, with the greatest losses in the buried relict A horizon soil, followed by the mid-layer legacy sediment and surface legacy sediment horizons. The 15N remaining in the soil following the post-drought leaching was highest in the mid-layer legacy sediment, intermediate in the surface legacy sediment, and lowest in the buried relict A horizon soil. Fluctuations in the water table at BSR which affect saturation of the buried relict A horizon soil could lead to great loses of NO3− from the soil, while vertical flow through the legacy-sediment-rich soil profile that originates in the surface has the potential to retain more NO3−. Restoration that seeks to reconnect the groundwater and surface water, which will decrease the number of drying–rewetting events imposed on the relict A horizon soils, could initially lead to increased losses of NO3− to nearby stream waters

The MRN complex in double-strand break repair and telomere maintenance

AbstractGenomes are subject to constant threat by damaging agents that generate DNA double-strand breaks (DSBs). The ends of linear chromosomes need to be protected from DNA damage recognition and end-joining, and this is achieved through protein–DNA complexes known as telomeres. The Mre11–Rad50–Nbs1 (MRN) complex plays important roles in detection and signaling of DSBs, as well as the repair pathways of homologous recombination (HR) and non-homologous end-joining (NHEJ). In addition, MRN associates with telomeres and contributes to their maintenance. Here, we provide an overview of MRN functions at DSBs, and examine its roles in telomere maintenance and dysfunction

The fundamental problem of command : plan and compliance in a partially centralised economy

When a principal gives an order to an agent and advances resources for its implementation, the temptations for the agent to shirk or steal from the principal rather than comply constitute the fundamental problem of command. Historically, partially centralised command economies enforced compliance in various ways, assisted by nesting the fundamental problem of exchange within that of command. The Soviet economy provides some relevant data. The Soviet command system combined several enforcement mechanisms in an equilibrium that shifted as agents learned and each mechanism's comparative costs and benefits changed. When the conditions for an equilibrium disappeared, the system collapsed.Comparative Economic Studies (2005) 47, 296–314. doi:10.1057/palgrave.ces.810011

Peer-group and price influence students drinking along with planned behaviour

This article is available open access through the publisher’s website at the link below. Copyright @ 2008 The Authors.Aims: To examine the theory of planned behaviour (TPB), as a framework for explaining binge drinking among young adults. Methods: One hundred and seventy-eight students in a cross-sectional design study completed self-report questionnaires examining attitudes to drinking, intention to drink and drinking behaviour in university. Binge drinking was defined for females (and males) as consuming ‘four (males—five) or more pints of beer/glasses of wine/measures of spirits’ in a single session. Results: Drinking alcohol was common; 39.6% of males and 35.9% of females reported binge drinking. The TPB explained 7% of the variance in intention to drink. Overall, 43% of the variance in intention, 83% of the variance in total weekly consumption and 44% of the variance in binge drinking was explained. The frequency of drinking and the drinking behaviour of friends significantly predicted intention to drink and binge drinking, respectively. Binge drinkers were influenced by peers and social-situational factors. Pressure to drink was greater for males; undergraduates were influenced by the size of the drinking group, ‘special offer’ prices, and the availability of alcohol. Conclusions: The TPB appeared to be a weak predictor of student drinking but this may be a result of how constructs were measured. With friends’ drinking behaviour emerging as a significant predictor of alcohol consumption, interventions seeking to reduce excessive drinking should target the role of peers and the university environment in which drinking occurs