Testosterone upregulates lipoprotein status to control sexual attractiveness in a colorful songbird

A salient feature of many secondary sexual characteristics in animals is that their expression is controlled by sex-steroid hormones. However, for only a few types of ornaments do we know the precise molecular mechanism by which androgens like testosterone (T) enhance trait production. We studied the red carotenoid-based beak of male zebra finches (Taeniopygia guttata), which serves as a sexually selected trait and is thought to be T dependent. In previous research, we demonstrated that the extent to which male finches produce lipoproteins in the bloodstream, which bind carotenoid pigments acquired from the diet and transport them to peripheral tissues, regulates the accumulation of carotenoids in the body and beak pigmentation. Here we show that T acts to upregulate lipoprotein production and allows male zebra finches to display flashy, sexually attractive coloration. Levels of circulating T in blood positively and significantly predicted lipoprotein profile (as measured by cholesterol levels), blood carotenoid concentration, and beak color. Exogenous T administration elevated cholesterol and carotenoid status as well as beak redness. Last, experimental inhibition of T (using the anti-androgen flutamide) downregulated lipoprotein production and carotenoid circulation and faded the beak. This androgen- and lipoprotein-mediated system represents one of the more detailed physiological mechanisms underlying the development of a sex-steroid-dependent trait in animals.     

The value of small size: loss of forest patches and ecological thresholds in southern Madagascar.

Many services generated by forest ecosystems provide essential support for human well-being. However, the vulnerability of these services to environmental change such as forest fragmentation are still poorly understood. We present spatial modeling of the generation of ecosystem services in a human-dominated landscape where forest habitat patches, protected by local taboos, are located in a matrix of cultivated land in southern Madagascar. Two ecosystem services dependent on the forest habitats were addressed: (1) crop pollination services by wild and semidomesticated bees (Apoidea), essential for local crop production of, for example, beans, and (2) seed dispersal services based on the presence of ring-tailed lemurs (Lemur catta). We studied the vulnerability of these ecosystem services to a plausible scenario of successive destruction of the smallest habitat patches. Our results indicate that, in spite of the fragmented nature of the landscape, the fraction of the landscape presently covered by both crop pollination and seed dispersal services is surprisingly high. It seems that the taboo system, though indirectly and unintentionally, contributes to upholding the generation of these services by protecting the forest patches. Both services are, however, predicted to be very vulnerable to the successive removal of small patches. For crop pollination, the rate of decrease in cover was significant even when only the smallest habitat patches were removed. The capacity for seed dispersal across the landscape displayed several thresholds with habitat patch removal. Our results suggest that, in order to maintain capacity for seed dispersal across the landscape and crop pollination cover in southern Androy, the geographical location of the remaining forest patches is more crucial than their size. We argue that in heavily fragmented production landscapes, small forest patches should increasingly be viewed as essential for maintaining ecosystem services, such as agricultural production, and also should be considered in the ongoing process of tripling the area of protected habitats in Madagascar.     

Light,timing of biological rhythms,and chronodisruption in man

This paper reviews abundant evidence suggesting that causes and course of aging and cancers can be considered as being both light- and rhythm-related. We define chronodisruption as a relevant disturbance of orderly biological rhythms over days and seasons and years in man. Light is the primary external mediator and melatonin a primary internal intermediary of such disturbances, which can result in earlier deaths via premature aging and cancers. We conclude that experimental and epidemiological research can provide further insights into common denominators of these chronic processes and may offer novel and uniform targets for prevention.     

Prenatal diagnosis of giant cystic hygroma: Prognosis,counselling, and management; case presentation and review of the recent literature

Cystic hygromas have historically been associated with a grim prognosis when discovered during prenatal sonographic study of the fetus. This same grim prognosis is not observed by the paediatric surgeon who evaluates the neonate or paediatric patient. We present a fetal patient with a massive anterior cystic hygroma discovered in the third trimester prior to 30 weeks. This case and a review of the literature suggest tailoring the prognosis by category when counselling patients: (1) first trimester, normal karyotype-good; (2) first trimester, abnormal karyotype-poor; (3) second trimester and early third-poor to guarded; and (4) mid to late third trimester-good.     

Low frequency electromagnetic waves as a supplemental energy source to sustain microbial growth?

Microbial populations in tetra-distilled water collapsed when cultured in a permalloy chamber shielding the populations from the suns and earths electromagnetic field, but thrived when cultured in an ordinary thermostat open to the electromagnetic field. Theoretically, protons in liquid water can be excited at their natural resonance frequencies through Langmuir oscillations and obtain enough kinetic energy to charge the transmembrane potential of a cell. Microbes may be capable of converting this energy into chemical energy to supplement their energy needs.     

The prenatal determination of glucose-6-phosphatase activity by fetal liver biopsy

Two fetuses at risk for glucose-6-phosphatase deficiency had in utero liver biopsies. Analysis of each showed this enzyme activity to be in the normal range and the pregnancies continued. Neither child has any clinical or metabolic evidence of glucose-6-phosphatase deficiency.     

Hydrodynamic Modeling Improves Green River Reconnection with Floodplain Wetlands for Endangered Fish Species Recovery

We performed two‐dimensional (2D) hydrodynamic modeling to aid recovery of the endangered razorback sucker (Xyrauchen texanus) by reconnecting the Green River with its historic bottomland floodplain wetlands at Ouray National Wildlife Refuge, Utah. Reconnection allows spring flood flows to overtop the river levee every two to three years, and passively transport razorback sucker larvae to the wetlands to grow in critical habitat. This study includes (1) river hydrologic analysis, (2) simulation of a levee breach/weir, overtopping of river flood flows, and 2D flow through the wetlands using Hydrologic Engineering Center River Analysis System 2D, and (3) modeling flow and restoration scenarios. Indicators of hydrologic alteration were used to evaluate river flow metrics, in particular flood magnitudes, frequency, and duration. Results showed a target spring flow of 16,000 cfs (453 m³/s) and a levee breach elevation of 4,663 ft (1,421 m) amsl would result in a median flow >6,000 acre‐feet (7.4 million m³) over five days into the wetlands, which is adequate for razorback sucker larvae transport and rearing. Modeling of flow/restoration scenarios showed using gated water control structures and passive low‐water crossings between wetland units can provide adequate control of flow movement into and storage in multiple units. Levee breaching can be a relatively simple, cost‐effective method to reconnect rivers and historic floodplains, and hydrodynamic modeling is an important tool for analyzing and designing wetland reconnection.     

Road Erosion and Delivery Index (READI): A Model for Evaluating Unpaved Road Erosion and Stream Sediment Delivery

The Road Erosion and Delivery Index (READI) is a new geographic information system–based model to assess erosion and delivery of water and sediment from unpaved road networks to streams. READI quantifies the effectiveness of existing road surfacing and drain placements in reducing road sediment delivery and guides upgrades to optimize future reductions. Roads are draped on a digital elevation model and parsed into hydrologically distinct segments. Segments are further divided by engineered drainage structures. For each segment, a kinematic wave approximation generates runoff hydrographs for specified storms, with discharge directly to streams at road–stream crossings and onto overland‐flow plumes at other discharge points. Plumes are attenuated by soil infiltration, which limits their length, with delivery occurring if plumes intersect streams. Sediment production and sediment delivery can be calculated as a relative dimensionless index. READI predicts only a small proportion of new drains and new surfacing results in the majority of sediment delivery reductions. The model illustrates how the spatial relationships between road and stream networks, controlled by topography and network geometries, influence patterns of road–stream connectivity. READI was applied in seven northern California basins. The model was also applied in a recent burn area to examine how reduced hillslope infiltration can result in increased hydrologic connectivity and sediment delivery.