Non-linear Microwave Surface Impedance of Epitaxial HTS Thin Films in Low DC Magnetic Fields

We have carried out non-linear microwave (8 GHz) surface impedance measurements of three YBaCuO thin films in dc magnetic fields $H_{dc}$ (parallel to c axis) up to 12 mT using a coplanar resonator technique. In zero dc field the three films, deposited by the same method, show a spread of low-power residual surface resistance, $R_{res}$ and penetration depth, $\lambda$ (T=15 K) within a factor of 1.9. However, they exhibit dramatically different microwave field, $H_{rf}$ dependences of the surface resistance, $R_s$, but universal $X_s(H_{rf})$ dependence. Application of a dc field was found to affect not only absolute values of $R_s$ and $X_s$, but the functional dependences $R_s(H_{rf})$ and $X_s(H_{rf})$ as well. For some of the samples the dc field was found to decrease $R_s$ below its zero-field low-power value.Comment: 4 pages, 4 figures. To be published in IEEE Trans. Appl. Supercond., June 199

Renal Transplantation and Pregnancy

Introduction: Although pregnancy after kidney transplantation is feasible, complications are relatively common and this needs to be considered in patient counseling and clinical decision making.Review: Fertility generally returns after renal transplantation. Approximately 74% of pregnancies in kidney transplant recipients end successfully in life births. Published reports suggest that pregnancy has no adverse affects on graft survival although patients with higher pre-pregnancy serum creatinine have a trend toward increased post-pregnancy serum creatinine. There is, however, a significantly increased risk of preeclampsia, gestational diabetes, cesarean section and preterm delivery compared to the general population. Almost half life births are preterm, and low birth weight is very common. Immunosuppressive medications are required to be continued during pregnancy in transplant recipients to prevent graft rejection, except for  sirolimus and mycophenolate mofetil (MMF) which are contraindicated during pregnancy. The incidence of birth defects in the live born is similar to the general population, except for pregnancies exposed to MMF which have a high incidence of birth defects. Every female in the reproductive age group should be counseled regarding pregnancy including the potential risks to the graft, to the mother and to the child. Timing pregnancy should be based upon whether graft function is optimal, but the general recommendation is to wait one year post transplantation before conception.Conclusion: Pregnancy in renal transplant patients should be planned with combined care from surgeons, nephrologists, obstetricians, pediatricians and dietitians which offers the best chance of a favorable outcome in the mother and the fetus

Conservation Agriculture for Food Security and Climate Resilience in Nepal

Achieving the sustainable development goals of the United Nations requires innovations in agriculture and development of climate-smart and economically feasible approaches for smallholder farmers in developing countries. Historical climate data of Nepal, which include 116 yr since 1901, has shown an increasing trend for average temperature by 0.016 ˚C yr–1 whereas precipitation has shown a decreasing trend by 0.137 mm yr–1. Such weather trends could enhance glacier melt associated flooding, and delayed monsoon rainfalls negatively impacting the agricultural production. The Nepalese government is promoting conservation agriculture (CA) through development of low-cost technologies that can be used effectively in difficult terrains. Such techniques include crop diversification, crop rotation, cover crops, and minimum tillage; all of which can reduce soil degradation. In addition, increasing crop residue retention can result in greater C sequestration and crop yield and reductions in greenhouse gas emissions. However, there is still lack of consensus on the merits of CA in the context of smallholder farming systems in Nepal. This paper reviews existing literature and provides an overview of farming practices in Nepal, highlights near-term challenges associated with climate change and food security, and discusses the role of CA as a climate-smart strategy to minimize soil degradation and improve food security