Are we saving water? Simple methods for assessing the effectiveness of groundwater conservation measures

Substantial storage reductions by irrigation pumping in many of the world’s major aquifers jeopardize future food production. As a result, new conservation measures are being utilized to reduce pumping and extend aquifer lifespans. The key question is how effective are these practices in attaining true water conservation (i.e., water use reduction) for a given area? Relationships between pumping and precipitation help provide an answer, as precipitation explains most of the variation in annual irrigation water use for aquifers in semi-arid to sub-humid climates when surface water supplies are limited. Our objective is to utilize correlations between radar precipitation and irrigation groundwater use at a range of spatial scales to assess the effectiveness of conservation approaches in the High Plains aquifer in the central USA. Linear regressions between pumping and precipitation for a conservation area established in 2013 in northwest Kansas indicate that water use and water use per irrigated area were over 27 % less and 25 % less, respectively, during 2013–2021 compared to the same climatic conditions during 2005–2012. Similar regressions found over a 38 % reduction and 23 % reduction in irrigation water use and use per irrigated area, respectively, during 2018–2021 compared to the same conditions during 2005–2017 in a west-central Kansas county with conservation areas. A decrease in irrigated area accounted for most of the difference between these reductions. Higher R2 values after conservation area establishment imply that irrigation tracks precipitation better due to use of soil moisture sensors and other measures as part of increased irrigation efficiency and enhanced water management. The precipitation and water use relationships, which are statistically significant for a wide range of spatial scales, have great potential for assessing the effectiveness of conservation practices in areas with high-quality water use and precipitation data

Reversible silencing of lumbar spinal interneurons unmasks a task-specific network for securing hindlimb alternation

Neural circuitry in the lumbar spinal cord governs two principal features of locomotion, rhythm and pattern, which reflect intra- and interlimb movement. These features are functionally organized into a hierarchy that precisely controls stepping in a stereotypic, speed-dependent fashion. Here, we show that a specific component of the locomotor pattern can be independently manipulated. Silencing spinal L2 interneurons that project to L5 selectively disrupts hindlimb alternation allowing a continuum of walking to hopping to emerge from the otherwise intact network. This perturbation, which is independent of speed and occurs spontaneously with each step, does not disrupt multi-joint movements or forelimb alternation, nor does it translate to a non-weight-bearing locomotor activity. Both the underlying rhythm and the usual relationship between speed and spatiotemporal characteristics of stepping persist. These data illustrate that hindlimb alternation can be manipulated independently from other core features of stepping, revealing a striking freedom in an otherwise precisely controlled system

Importance of a sound hydrologic foundation for assessing the future of the High Plains Aquifer in Kansas

This is the published version. Copyright National Academy of SciencesSteward et al. (1) assess the hydrologic and agricultural future of the High Plains Aquifer. We have many concerns about hydrologic aspects of their study and describe the most significant here. The authors state “…the lines of recharge plus storage in Fig. 1C very closely approximate the recent data points of metered groundwater pumping….” That is not correct, as is clear from a comparison of reported pumping data (diamonds) and the authors’ calculated groundwater use (solid line) for the SW region. There is a systematic deviation (authors’ calculated use is increasing, whereas reported metered pumping data are decreasing), which persists even when uncertain pre-1990 pumping data are neglected. The authors’ groundwater use is also markedly inconsistent with common experiences in western Kansas (2). The 2020–2025 (SW) and 2025–2030 (NW) peaks in the authors’ groundwater use are simply a product of their logistic function representation (maximum use at normalized thickness of 0.5) and are in dramatic contrast to recorded pumping trends. Given that calculated groundwater use is input into the agricultural models, we question all of the agricultural projections. The authors provide no objective basis for accepting the logistic function as an accurate tool for projecting water level declines. The comparisons in their table S1 do little to substantiate the use of the function given that the authors (i) adjust two parameters per well; (ii) adjust parameters at each well independently of the other 1,600 wells; and (iii) in aggregate, only assess the first 30% of depletion. A number of alternative functions could be found that would produce similar agreement with existing data but markedly different future projections. We note the circularity of including extrapolated 2060 values in the dataset used to develop logistic curves that are then used to make future projections. The authors state “…and measurement points were added at 1930 and 2060 from a linear extrapolation of observations while keeping these points within the saturated aquifer.” We are concerned about the sensitivity of future projections to inclusion of 1930 and 2060 “measurements” and to the process (unexplained) for “keeping these points within the saturated aquifer.” The authors state that “We computed recent recharge rates to preserve conservation of mass….” That cannot be correct, as is clear from a comparison of reported pumping data (diamonds) and the authors’ calculated change in storage plus recharge (solid line) for the SW region in their figure 1C; a conservation of mass calculation would produce a line through the center of mass of the reported 1981–2009 data. The calculated recharge values appear to have been adjusted in an unexplained manner. Given that, we also question the significance of the match obtained for the groundwater-supported corn plot in their figure 3A. The comparisons in their table S3 do little to substantiate the authors’ recharge estimates because of the above concerns and the lack of consistency with more recent process-based modeling investigations (3, 4). We conclude that this is an interesting, but highly flawed, mathematical exercise that has little bearing on future conditions in the High Plains Aquifer in western Kansas

Estimating the Continuous-Time Dynamics of Energy and Fat Metabolism in Mice

The mouse has become the most popular organism for investigating molecular mechanisms of body weight regulation. But understanding the physiological context by which a molecule exerts its effect on body weight requires knowledge of energy intake, energy expenditure, and fuel selection. Furthermore, measurements of these variables made at an isolated time point cannot explain why body weight has its present value since body weight is determined by the past history of energy and macronutrient imbalance. While food intake and body weight changes can be frequently measured over several weeks (the relevant time scale for mice), correspondingly frequent measurements of energy expenditure and fuel selection are not currently feasible. To address this issue, we developed a mathematical method based on the law of energy conservation that uses the measured time course of body weight and food intake to estimate the underlying continuous-time dynamics of energy output and net fat oxidation. We applied our methodology to male C57BL/6 mice consuming various ad libitum diets during weight gain and loss over several weeks and present the first continuous-time estimates of energy output and net fat oxidation rates underlying the observed body composition changes. We show that transient energy and fat imbalances in the first several days following a diet switch can account for a significant fraction of the total body weight change. We also discovered a time-invariant curve relating body fat and fat-free masses in male C57BL/6 mice, and the shape of this curve determines how diet, fuel selection, and body composition are interrelated

Oral contraceptive use and ovarian cancer risk among carriers of BRCA1 or BRCA2 mutations

Women with mutations of the genes BRCA1 or BRCA2 are at increased risk of ovarian cancer. Oral contraceptives protect against ovarian cancer in general, but it is not known whether they protect against the disease in carriers of these mutations. We obtained self-reported lifetime histories of oral contraceptive use from 451 women who carried mutations of BRCA1 or BRCA2. We used conditional logistic regression to estimate the odds ratios associated with oral contraceptive use, comparing the histories of 147 women with ovarian cancer (cases) to those of 304 women without ovarian cancer (controls) who were matched to cases on year of birth, country of residence and gene (BRCA1 vs BRCA2). Reference ages for controls had to exceed the ages at diagnosis of their matched cases. After adjusting for parity, the odds-ratio for ovarian cancer associated with use of oral contraceptives for at least 1 year was 0.85 (95 percent confidence interval, 0.53-1.36). The risk decreased by 5% (1-9%) with each year of use (P for trend=0.01). Use for 6 or more years was associated with an odds-ratio of 0.62 (0.35-1.09). These data support the hypothesis that long-term oral contraceptive use reduces the risk of ovarian cancer among women who carry mutations of BRCA1 or BRCA2

Vietnam military service history and prostate cancer

BACKGROUND: Three decades after US and Australian forces withdrew from Vietnam, there has been much public interest in the health consequences of service in Vietnam. One controversial question is whether the risk of prostate cancer amongst Vietnam veterans is increased. This paper examines relationships between military history, family history and risk of prostate cancer in a population-based case control study. METHODS: Cases were selected from the Cancer Registry of Western Australia as incident cases of histologically-confirmed prostate cancer, and controls were age-matched and selected from the Western Australian electoral roll. Study participants were asked to report any military service history and details about that service. RESULTS: Between January 2001 and September 2002, 606 cases and 471 controls aged between 40–75 years were recruited. An increased prostate cancer risk was observed in men reporting they were deployed in Vietnam although this was not statistically significant (OR = 2.12; 95% CI 0.88–5.06). An increased risk was also observed in men reporting prostate cancer in fathers (OR = 1.90; 95% CI 1.20–3.00) or brothers (OR = 2.05; 95% CI 1.20–3.50) diagnosed with prostate cancer. CONCLUSION: These findings support a positive association between prostate cancer and military service history in the Vietnam war and a first degree relative family history of prostate cancer

CAG repeat length in the androgen receptor gene is related to age at diagnosis of prostate cancer and response to endocrine therapy, but not to prostate cancer risk

The length of the polymorphic CAG repeat in the N-terminal of the androgen receptor (AR) gene is inversely correlated with the transactivation function of the AR. Some studies have indicated that short CAG repeats are related to higher risk of prostate cancer. We performed a case–control study to investigate relations between CAG repeat length and prostate cancer risk, tumour grade, tumour stage, age at diagnosis and response to endocrine therapy. The study included 190 AR alleles from prostate cancer patients and 186 AR alleles from female control subjects. All were whites from southern Sweden. The frequency distribution of CAG repeat length was strikingly similar for cases and controls, and no significant correlation between CAG repeat length and prostate cancer risk was detected. However, for men with non-hereditary prostate cancer (n = 160), shorter CAG repeats correlated with younger age at diagnosis (P = 0.03). There were also trends toward associations between short CAG repeats and high grade (P = 0.07) and high stage (P = 0.07) disease. Furthermore, we found that patients with long CAG repeats responded better to endocrine therapy, even after adjusting for pretreatment level of prostate-specific antigen and tumour grade and stage (P = 0.05). We conclude that short CAG repeats in the AR gene correlate with young age at diagnosis of prostate cancer, but not with higher risk of the disease. Selection of patients with early onset prostate cancer in case–control studies could therefore lead to an over-estimation of the risk of prostate cancer for men with short CAG repeats. An association between long CAG repeats and good response to endocrine therapy was also found, but the mechanism and clinical relevance are unclear. © 1999 Cancer Research Campaig

Low urine pH and acid excretion do not predict bone fractures or the loss of bone mineral density: a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>The acid-ash hypothesis, the alkaline diet, and related products are marketed to the general public. Websites, lay literature, and direct mail marketing encourage people to measure their urine pH to assess their health status and their risk of osteoporosis.</p> <p>The objectives of this study were to determine whether 1) low urine pH, or 2) acid excretion in urine [sulfate + chloride + 1.8x phosphate + organic acids] minus [sodium + potassium + 2x calcium + 2x magnesium mEq] in fasting morning urine predict: a) fragility fractures; and b) five-year change of bone mineral density (BMD) in adults.</p> <p>Methods</p> <p>Design: Cohort study: the prospective population-based Canadian Multicentre Osteoporosis Study. Multiple logistic regression was used to examine associations between acid excretion (urine pH and urine acid excretion) in fasting morning with the incidence of fractures (6804 person years). Multiple linear regression was used to examine associations between acid excretion with changes in BMD over 5-years at three sites: lumbar spine, femoral neck, and total hip (n = 651). Potential confounders controlled included: age, gender, family history of osteoporosis, physical activity, smoking, calcium intake, vitamin D status, estrogen status, medications, renal function, urine creatinine, body mass index, and change of body mass index.</p> <p>Results</p> <p>There were no associations between either urine pH or acid excretion and either the incidence of fractures or change of BMD after adjustment for confounders.</p> <p>Conclusion</p> <p>Urine pH and urine acid excretion do not predict osteoporosis risk.</p

Non-Hodgkin's lymphoma, obesity and energy homeostasis polymorphisms

A population-based case–control study of lymphomas in England collected height and weight details from 699 non-Hodgkin's lymphoma (NHL) cases and 914 controls. Obesity, defined as a body mass index (BMI) over 30 kg m−2 at five years before diagnosis,, was associated with an increased risk of NHL (OR=1.5, 95% CI 1.1–2.1). The excess was most pronounced for diffuse large B-cell lymphoma (OR=1.9, 95% CI 1.3–2.8). Genetic variants in the leptin (LEP 19G>A, LEP −2548G>A) and leptin receptor genes (LEPR 223Q>R), previously shown to modulate NHL risk, as well as a polymorphism in the energy regulatory gene adiponectin (APM1 276G>T), were investigated. Findings varied with leptin genotype, the risks being decreased with LEP 19AA (OR=0.7, 95% CI 0.5–1.0) and increased with LEP −2548GA (OR=1.3, 95% CI 1.0–1.7) and −2548AA (OR=1.4, 95% CI 1.0–1.9), particularly for follicular lymphoma. These genetic findings, which were independent of BMI, were stronger for men than women

A prospective study of postmenopausal hormone use and ovarian cancer risk

The relationship between postmenopausal hormone use (PMH) and ovarian cancer risk is unclear, particularly for specific hormone formulations, but recent studies suggest that there is a positive association. We conducted a prospective observational study with 82 905 postmenopausal women, including 389 ovarian cancers, in the Nurses' Health Study from 1976 to 2002. Compared with never users of PMH, both current and past users of ⩾5 years had a significantly elevated risk of ovarian cancer (RR=1.41, 95% confidence interval (CI) 1.07–1.86 and relative risk (RR)=1.52, 95% CI 1.01–2.27, respectively). Examined by hormone type in continuous years, use of unopposed estrogen was associated with a significant increase in the risk of epithelial ovarian cancer (P for trend <0.001; RR for 5-year increment of use=1.25, 95% CI 1.12–1.38). Use of estrogen plus progestin (RR for 5-year increment of use=1.04, 95% CI 0.82–1.32) was not significantly associated with ovarian cancer risk. Generally, results were similar for serous tumours (RR for 5-year increment of unopposed estrogen use=1.23, 95% CI 1.07–1.40) and slightly stronger for endometrioid tumours (RR for 5-year increment of unopposed estrogen use=1.53, 95% CI 1.20–1.94). Recency of use was not significantly associated with ovarian cancer risk, but statistical power was limited here