bluuebunny/crossref_metadata_2025 huggingface dataset:
Lumbar Spinal Stenosis: How Is It Classified?
Authors: Schroeder Gregory D. , Kurd Mark F. , Vaccaro Alexander R.
Published: November 2016

The prevalence of lumbar spinal stenosis is approximately 9.3%, with people most commonly affected in the sixth or seventh decade of life. Patients often have pain, cramping, and weakness in their legs that is worsened with standing and walking. Although the Spine Patient Outcomes Research Trial clearly demonstrated that surgery improves health-related quality of life, treatment for lumbar spinal stenosis varies widely from the type of decompression performed to the need for fusion. This variability can be attributed largely to the lack of an accepted classification system. A good classification system serves as a common language to define the severity of a condition, guide treatment, and facilitate clinical research.
Green Building and LEED Certification in the Water Utility Sector
Authors: Job Charles A.
Published: November 2016

Recent water and wastewater projects that have achieved LEED certification indicate broad opportunities for sustainable construction and operation.
Rightsizing
Authors: Mercer Kenneth L.
Published: November 2016

Although it's common to hear about water scarcity framed as a looming worldwide crisis, many communities are in fact seeing declines in water demand. For systems near the limits of their current water supplies, the realization of ongoing conservation efforts is welcome relief. But for some older communities where freshwater is plentiful, it's the loss of residents, not improved efficiency, that has caused demand to drop.
Nothing New Under the Sun
Authors: Bernosky Joseph
Published: November 2016

This column considers issues that water communities of 50, 75, or even 100 years ago encountered and how they addressed those issues. The water challenges we face today aren't much different.
Dynamic metabolic exchange governs a marine algal-bacterial interaction
Authors: Segev Einat , Wyche Thomas P , Kim Ki Hyun , Petersen Jörn , Ellebrandt Claire , Vlamakis Hera , Barteneva Natasha , Paulson Joseph N , Chai Liraz , Clardy Jon , Kolter Roberto
Published: November 2016

Emiliania huxleyi is a model coccolithophore micro-alga that generates vast blooms in the ocean. Bacteria are not considered among the major factors influencing coccolithophore physiology. Here we show through a laboratory model system that the bacterium Phaeobacter inhibens, a well-studied member of the Roseobacter group, intimately interacts with E. huxleyi. While attached to the algal cell, bacteria initially promote algal growth but ultimately kill their algal host. Both algal growth enhancement and algal death are driven by the bacterially-produced phytohormone indole-3-acetic acid. Bacterial production of indole-3-acetic acid and attachment to algae are significantly increased by tryptophan, which is exuded from the algal cell. Algal death triggered by bacteria involves activation of pathways unique to oxidative stress response and programmed cell death. Our observations suggest that bacteria greatly influence the physiology and metabolism of E. huxleyi. Coccolithophore-bacteria interactions should be further studied in the environment to determine whether they impact micro-algal population dynamics on a global scale.
Decoding gripping force based on local field potentials recorded from subthalamic nucleus in humans
Authors: Tan Huiling , Pogosyan Alek , Ashkan Keyoumars , Green Alexander L , Aziz Tipu , Foltynie Thomas , Limousin Patricia , Zrinzo Ludvic , Hariz Marwan , Brown Peter
Published: November 2016

The basal ganglia are known to be involved in the planning, execution and control of gripping force and movement vigour. Here we aim to define the nature of the basal ganglia control signal for force and to decode gripping force based on local field potential (LFP) activities recorded from the subthalamic nucleus (STN) in patients with deep brain stimulation (DBS) electrodes. We found that STN LFP activities in the gamma (55–90 Hz) and beta (13–30m Hz) bands were most informative about gripping force, and that a first order dynamic linear model with these STN LFP features as inputs can be used to decode the temporal profile of gripping force. Our results enhance the understanding of how the basal ganglia control gripping force, and also suggest that deep brain LFPs could potentially be used to decode movement parameters related to force and movement vigour for the development of advanced human-machine interfaces.
Smad4 restricts differentiation to promote expansion of satellite cell derived progenitors during skeletal muscle regeneration
Authors: Paris Nicole D , Soroka Andrew , Klose Alanna , Liu Wenxuan , Chakkalakal Joe V
Published: November 2016

Skeletal muscle regenerative potential declines with age, in part due to deficiencies in resident stem cells (satellite cells, SCs) and derived myogenic progenitors (MPs); however, the factors responsible for this decline remain obscure. TGFβ superfamily signaling is an inhibitor of myogenic differentiation, with elevated activity in aged skeletal muscle. Surprisingly, we find reduced expression of Smad4, the downstream cofactor for canonical TGFβ superfamily signaling, and the target Id1 in aged SCs and MPs during regeneration. Specific deletion of Smad4 in adult mouse SCs led to increased propensity for terminal myogenic commitment connected to impaired proliferative potential. Furthermore, SC-specific Smad4 disruption compromised adult skeletal muscle regeneration. Finally, loss of Smad4 in aged SCs did not promote aged skeletal muscle regeneration. Therefore, SC-specific reduction of Smad4 is a feature of aged regenerating skeletal muscle and Smad4 is a critical regulator of SC and MP amplification during skeletal muscle regeneration.
Splicing repression allows the gradual emergence of new Alu-exons in primate evolution
Authors: Attig Jan , Ruiz de los Mozos Igor , Haberman Nejc , Wang Zhen , Emmett Warren , Zarnack Kathi , König Julian , Ule Jernej
Published: November 2016

Alu elements are retrotransposons that frequently form new exons during primate evolution. Here, we assess the interplay of splicing repression by hnRNPC and nonsense-mediated mRNA decay (NMD) in the quality control and evolution of new Alu-exons. We identify 3100 new Alu-exons and show that NMD more efficiently recognises transcripts with Alu-exons compared to other exons with premature termination codons. However, some Alu-exons escape NMD, especially when an adjacent intron is retained, highlighting the importance of concerted repression by splicing and NMD. We show that evolutionary progression of 3' splice sites is coupled with longer repressive uridine tracts. Once the 3' splice site at ancient Alu-exons reaches a stable phase, splicing repression by hnRNPC decreases, but the exons generally remain sensitive to NMD. We conclude that repressive motifs are strongest next to cryptic exons and that gradual weakening of these motifs contributes to the evolutionary emergence of new alternative exons.
Sec24 phosphorylation regulates autophagosome abundance during nutrient deprivation
Authors: Davis Saralin , Wang Juan , Zhu Ming , Stahmer Kyle , Lakshminarayan Ramya , Ghassemian Majid , Jiang Yu , Miller Elizabeth A , Ferro-Novick Susan
Published: November 2016

Endoplasmic Reticulum (ER)-derived COPII coated vesicles constitutively transport secretory cargo to the Golgi. However, during starvation-induced stress, COPII vesicles have been implicated as a membrane source for autophagosomes, distinct organelles that engulf cellular components for degradation by macroautophagy (hereafter called autophagy). How cells regulate core trafficking machinery to fulfill dramatically different cellular roles in response to environmental cues is unknown. Here we show that phosphorylation of conserved amino acids on the membrane-distal surface of the Saccharomyces cerevisiae COPII cargo adaptor, Sec24, reprograms COPII vesicles for autophagy. We also show casein kinase 1 (Hrr25) is a key kinase that phosphorylates this regulatory surface. During autophagy, Sec24 phosphorylation regulates autophagosome number and its interaction with the C-terminus of Atg9, a component of the autophagy machinery required for autophagosome initiation. We propose that the acute need to produce autophagosomes during starvation drives the interaction of Sec24 with Atg9 to increase autophagosome abundance.
Environmental Sustainability Assessment of Agricultural Practices in the Malagos Watershed, Davao City, Philippines
Authors: Cadena Hector B.
Published: November 2016

This study describes the agricultural production practices of the farmers in the Malagos Watershed, Davao City, Philippines. This was done given the new trends in Ecoagriculture and Permaculture principles. The different Agricultural practices were described and assessed in terms of sustainability. Sustainable Agriculture is the production of food and other farm products in ways that protect the environment, public health and animal welfare. Practices need to be modified if they are causing damage to these factors instead.  As to crops planted, which included cereals, vegetables and fruits, sustainability was rated fair. Tools and equipment used together with the method of cultivation were rated highly sustainable.  Fertilizers used and method of fertilizer application which was mostly (40%) commercial fertilizers applied through basal and broadcast method, were rated sustainable.  The method of irrigation, which was mostly rainfed, was assessed as highly sustainable. The method of pests and disease control was the only practice rated poor since commercial chemical spray were commonly used and one potentially harmful to people and the environment.  Harvesting method, which was mostly by handpicking, was rated highly sustainable.  Their methods of storage, product disposal and waste disposal were all classified as fairly sustainable. Concerning livestock production, almost all of their practices, including, type of animal raised, method of animal housing, feeds used, method of watering, method of product disposal and method of waste disposal, all rated fairly sustainable.  Only the method of feeding, which mostly used dry feeds instead of free grazing, was graded sustainable. Crop production and livestock production in the Malagos Watershed averaged quite acceptable. It is, therefore, recommended that these practices be improved, maintained and monitored so that the agricultural practices in the Malagos Watershed would remain viable in the future. This study is the first attempt at assessing the sustainability of Agricultural practices of Indigenous peoples habituating the Malagos Watershed.
Ethnobotanical Study of Medicinal Plants for Diarrhea in Agusan del Sur, Philippines
Authors: Arquion Rose D.
Published: November 2016

Ethnobotany is the study of plants used by specific cultures for various purposes. This study aimed to document indigenous medicinal plants which can treat diarrhea. This qualitative study used semi –structured interview and employed purposive sampling of 50 local inhabitants aging 40 to 85 years old presently using medicinal plants in eight communities of Talacogon, Agusan del Sur, Philippines. Results revealed that 25 medicinal plants can treat diarrhea. The leaves and stem of these plants were utilized and prepared by decoction, infusion, concoction and extraction. Out of the 25 identified medicinal plants, Psidium guajava (guava), Persea americana (avocado), and Blumea balsamifera (Blumea camphor) were commonly used which easily grow and can be domesticated in home gardens. The medicinal plants had helped much the local people as a cheap source of alternative medicine. This suggests that this traditional knowledge from these people be transmitted through symposia, seminars and trainings for its management and conservation for sustainability.
Livelihood Needs Assessment in the Malagos Watershed, Davao City, Philippines: Implications to Ecology and Conservation
Authors: Cadena Ma. Leah E.
Published: November 2016

The study aimed at assessing the livelihood needs of the residents in the Malagos Watershed.  The residents in the area are mostly Indigenous Peoples (IPs).The study used descriptive-correlation design to describe the socio-demographic characteristics, livelihood needs and assistance, monthly household income, problems encountered by the respondents and the suggested solutions to the problems identified. The study collected primary data from the residents in the watershed with the use of an interview schedule. Random sampling was used to determine the samples from the different associations along the watershed. The study found out that most of the residents in the Malagos Watershed area are aged 36-60 years old, female, married, High School level in education, Diangan in tribe, Catholic, with 4-6 household size, housewives, and with monthly household income of P5,001-P10,000.Assessment of their livelihood needs had livestock and poultry raising as their priority.  Work, financial and educational assistance are most needed. There is a significant difference in monthly household income of respondents when they are grouped according to socio-demographic characteristics regarding age, civil status, tribe and religion. Most of the problems the residents identified were the lack of livelihood, finances, education, poor health, potable water, electricity, assistance in agricultural production.  To these, they suggested government support especially in infrastructure, health, education and financial help from government and/or nongovernment organizations.
Factors Influencing the Level of Conversion of Rice Fields into Catfish Farms in Los Amigos, Davao City, Philippines
Authors: Borres Beltran C. , Garillos Emmalinda A.
Published: November 2016

This descriptive-correlational study is used to determine the relationship between the level of conversion of rice fields into catfish farms and the current status of the factors which are rice farming, catfish farming, government programs in rice production, and environmental conditions.   There were 33 respondents considered in this study who were the catfish growers. Data gathered were analyzed using frequency counts and percentages, mean, and Pearson product correlation or Pearson r. The study found out that the level of perception of respondents was high on the current status of catfish farming and environmental conditions. For government programs on rice production, respondents had a moderately high level of perception. There is also a high level of conversion of rice fields into catfish farms. The test of difference showed that there is a highly significant difference in the level of conversion of rice fields into catfish farms when grouped according to rice farm area.  There is no significant difference in the level of conversion of rice fields into catfish farms when grouped according to demographic profile such as age, sex, educational attainment, seminars or training attended and high length of experience. The test of relationship showed that there is a significant relationship between the level of conversion of rice farming and the current status of catfish farming. Instead of fishing in the rivers, farmers may convert the lower portion of their rice fields into fish ponds. However, the test of relationship showed that there is no significant relationship between the level of conversion and the current status of rice farming, government programs on rice production, and environmental conditions.
Integrated Organic Farming for Community Development Effectively Bridges the Gaps in Agricultural Instruction, Research, and Extension: Experience of a Public University in an Asian Developing Country
Authors: GARAN LINA M.
Published: November 2016

This study was conducted in 2011 to 2012 under the aegis of the Cagayan State University-Sanchez Mira campus and the National Economic Development Authority under its Productivity Enhancement Program.  The study employed technology-demonstration on organic farming as an entry point in the community. Using the descriptive design, 90 farmers were trained on organic farming technologies and structured survey questionnaire and interviews were used to document the results. The concept was designed to facilitate farmers’ adoption of sustainable and environment-friendly technology in organic farming by integrating the following components: On-Site School on Organic Farming, Technology-Demonstration, Extension and Technical Assistance, and Research. The on-site school included greenhouses, field research, and techno-demo plots on vegetable and livestock, vermi-compost, apiary, and houses for native pigs and chickens. To showcase organic farming practices, a field day was conducted which was attended by 165 farmers, entrepreneurs, and other stakeholders.  Finally, the results showed that 90%, 80%, and 85% of the farmers from the three municipalities followed the technologies demonstrated to them.  Around 85% of the total respondents reported an 80% increase in their monthly income.  This was attributed to production of food and farm inputs.  These results conclude that technology-demonstration was effective in bridging the gaps in agricultural instruction, research, and extension for the adaptation of farmers.
CENÁRIO TECNOLÓGICO RELACIONADO À UTILIZAÇÃO DE RESÍDUOS PARA PRODUÇÃO DE BEBIDAS ALCOOLICAS
Authors: Coelho Emanuela Monteiro , Azevedo Luciana Cavalcanti
Published: November 2016

Frequentemente, a geração de resíduos industriais tem sido um tema de debate em vários setores econômicos. Por ser caracterizada como uma das maiores geradoras de resíduos orgânicos, a indústria alimentícia tem se dedicado a encontrar alternativas para o destino de seus resíduos, sendo a elaboração de bebidas alcoólicas uma delas. O levantamento realizado em bancos de patentes revela que nos últimos 40 anos, os países que se destacam com tecnologias de bebidas são: Estados Unidos, Alemanha e Japão, cujas patentes são registradas em maior numero pelas empresas privadas e cujos inventores também estão ligados a elas. No entanto, essas patentes estão relacionadas às tecnologias desenvolvidas para novas formulações que utilizam ingredientes funcionais, novos produtos e novas formas de apresentação (como em pó). O aproveitamento de resíduos para elaboração de bebidas alcoólicas ainda não é uma realidade nas indústrias de bebidas, mas já começa a despontar entre as tecnologias protegidas. Este novo nicho de mercado pode promover uma grande abertura comercial, já que envolve novas matérias-primas de baixo custo e que retiram do ambiente grandes volumes de resíduos orgânicos.
PROSPECÇÃO TECNOLÓGICA DO Morinda citrifolia L. NO PERÍODO DE 2006 A 2016
Authors: Da Conceição Lima Antonio Marcos
Published: November 2016

O presente trabalho teve como objetivo fazer um mapeamento tecnológico das pesquisas já desenvolvidas em torno do M. citrifolia L., avaliando as potencialidades tecnológicas por meio do depósito de patentes. Para tanto, foi realizada uma prospecção tecnológica nas bases de dados World Intellectual Property Organization (WIPO), European Patent Office (EPO), Derwent Innovation Index (DII), United States Patent and Trademark Office (USPTO) e Instituto Nacional de Propriedade Industrial do Brasil (INPI). Dentre as bases estudadas, a WIPO apresentou a maior quantidade de patentes depositadas. A classificação CIP A61K e A23L foram as mais presentes. O ano de 2007 apresentou o maior número de patentes depositadas. Os Estados Unidos aparecem como o maior depositante, enquanto que o Brasil mesmo com uma das produções científicas mais notáveis do mundo na área de produtos naturais, não tem conseguido mostrar o investimento em ciência e tecnologia na obtenção de patentes.
FRUTO DO MARACUJÁ: IMPORTÂNCIA ECONÔMICA E INDUSTRIAL, PRODUÇÃO, SUBPRODUTOS E PROSPECÇÃO TECNOLÓGICA
Authors: Coelho Emanuela Monteiro , Azevêdo Luciana Cavalcanti de , Umza-Guez Marcelo A
Published: November 2016

O trabalho objetivou-se realizar levantamento de produção, utilização e aproveitamento de resíduos do fruto do maracujá, assim como fazer estudo prospectivo avaliando o panorama mundial relativo à utilização do fruto e casca do maracujá. A revisão baseou-se em artigos científicos e a prospecção nos Bancos de dados do Europen Pantent Office (EPO) no Espacenet®, e no Instituto Nacional da Propriedade Industrial (INPI). Foram localizadas 234 patentes registradas na EPO e 24 no INPI, relacionadas com tecnologias com maracujá. Conclui-se que o reaproveitamento do resíduo do maracujá é uma alternativa, tanto para explorar o seu alto valor nutricional, quanto para a obtenção de produtos inovadores de alto potencial de mercado, visto a crescente valorização e consumo de alimentos saudáveis. Constatou-se também que o maior destino industrial para aproveitamento das cascas de maracujá tem sido em produtos alimentícios (68%), seguindo da indústria de fármacos (18%) e indústria de produtos agrícolas (14%).
Debates—Stochastic subsurface hydrology from theory to practice: The relevance of stochastic subsurface hydrology to practical problems of contaminant transport and remediation. What is characterization and stochastic theory good for?
Authors: Fiori A. , Cvetkovic V. , Dagan G. , Attinger S. , Bellin A. , Dietrich P. , Zech A. , Teutsch G.
Published: November 2016

The emergence of stochastic subsurface hydrology stemmed from the realization that the random spatial variability of aquifer properties has a profound impact on solute transport. The last four decades witnessed a tremendous expansion of the discipline, many fundamental processes and principal mechanisms being identified. However, the research findings have not impacted significantly the application in practice, for several reasons which are discussed. The paper discusses the current status of stochastic subsurface hydrology, the relevance of the scientific results for applications and it also provides a perspective to a few possible future directions. In particular, we discuss how the transfer of knowledge can be facilitated by identifying clear goals for characterization and modeling application, relying on recent recent advances in research in these areas.
Modeled Chl:C ratio and derived estimates of phytoplankton carbon biomass and its contribution to total particulate organic carbon in the global surface ocean
Authors: Arteaga Lionel , Pahlow Markus , Oschlies Andreas
Published: November 2016

Chlorophyll (Chl) is a distinctive component of autotrophic organisms, often used as an indicator of phytoplankton biomass in the ocean. However, assessment of phytoplankton biomass from Chl relies on the accurate estimation of the Chl:carbon(C) ratio. Here we present global patterns of Chl:C ratios in the surface ocean obtained from a phytoplankton growth model that accounts for the optimal acclimation of phytoplankton to ambient nutrient, light, and temperature conditions. The model agrees largely with observed/expected global patterns of Chl:C. Combining our Chl:C estimates with satellite Chl and particulate organic carbon (POC), we infer phytoplankton C concentration in the surface ocean and its contribution to the total POC pool. Our results suggest that the portion of POC corresponding to living phytoplankton is higher in subtropical latitudes and less productive regions (∼30–70%) and decreases to ∼10–30% toward high latitudes and productive regions. An important caveat of our model is the lack of iron limiting effects on phytoplankton physiology. Comparison of our predicted phytoplankton biomass with an independent estimate of total POC reveals a positive correlation between nitrate concentrations and nonphotosynthetic POC in the surface ocean. This correlation disappears when a constant Chl:C is applied. Our analysis is not constrained by assumptions of constant Chl:C or phytoplankton:POC ratio, providing a novel independent analysis of phytoplankton biomass in the surface ocean. These results highlight the importance of accounting for the variability in Chl:C and its application in distinguishing the autotrophic and heterotrophic components in the assemblage of the marine plankton ecosystem.
Dynamics of primary productivity in the northern South China Sea over the past 24,000 years
Authors: Zhang Hongrui , Liu Chuanlian , Jin Xiaobo , Shi Jiangnan , Zhao Shaohua , Jian Zhimin
Published: November 2016

In this study, paleoproductivity on millennial scales was precisely reconstructed from core MD12‐3428cq in the northern South China Sea (SCS) over the past 24 kyr, based on a transfer function derived from the strong exponential negative correlation between relative abundance of Florisphaera profunda (%FP) in core top sediments and basin‐wide satellite‐based primary productivity (PP) in the SCS. To detect the potential driving mechanisms of PP, correlation analyses were carried out among our PP records and other paleoenvironment parameters. PP peaked during 18–15 ka in parallel with the strong East Asian Winter Monsoon (EAWM). From 15 ka to the early Holocene, a decrease in PP coincided with sea level progradation and weakening of EAWM, which ultimately reduced fluvial nutrient levels and wind‐driven upper water column mixing. Since the middle Holocene, gradually more frequent El Niño‐Southern Oscillation (ENSO) events have taken place, further decreasing PP by injecting oligotrophic Kuroshio water masses into the northern SCS. Associated findings conclusively indicated that the main controlling factors of PP in the northern SCS have shifted from EAWM (glacial) to ENSO (interglacial) over the past 24 kyr.
Imaging crustal structure beneath the southern Appalachians with wavefield migration
Authors: Hopper E. , Fischer K. M. , Rondenay S. , Hawman R. B. , Wagner L. S.
Published: November 2016

To constrain crustal structures in the southern Appalachians and the suture zone with the Gondwanan‐affinity Suwannee terrane, we applied the 2‐D generalized Radon transform wavefield migration method to the scattered incident P wavefield recorded by the EarthScope Southeastern Suture of the Appalachian Margin Experiment and adjacent Transportable Array stations. We resolve the root of thickened crust beneath the high topography of the Blue Ridge Mountains and estimate its density contrast with the mantle to be only 104 ± 20 kg/m3. A weak velocity contrast across the crustal root Moho is observed and may be related to an ongoing crustal delamination event, possibly contributing to local tectonic rejuvenation. Beneath the Suwannee terrane, we confirm prior observations of a gently south‐southeastward dipping crustal suture, indicating the terminal collision of Laurentia and Gondwana involved several hundred kilometers of overthrusting.
Detection of human‐induced evapotranspiration using GRACE satellite observations in the Haihe River basin of China
Authors: Pan Yun , Zhang Chong , Gong Huili , Yeh Pat J.‐F. , Shen Yanjun , Guo Ying , Huang Zhiyong , Li Xiaojuan
Published: November 2016

Regional evapotranspiration (ET) can be enhanced by human activities such as irrigation or reservoir impoundment. Here the potential of using Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage data in water budget calculations to detect human‐induced ET change is investigated over the Haihe River basin of China. Comparison between GRACE‐based monthly ET estimate (2005–2012) and Global Land Data Assimilation System (GLDAS)‐modeled ET indicates that human‐induced ET due to intensive groundwater irrigation from March to May can only be detected by GRACE. GRACE‐based ET (521.7 ± 21.1 mm/yr), considerably higher than GLDAS ET (461.7 ± 29.8 mm/yr), agrees well with existing estimates found in the literature and indicates that human activities contribute to a 12% increase in ET. The double‐peak seasonal pattern of ET (in May and August) as reported in published studies is well reproduced by GRACE‐based ET estimate. This study highlights the unique capability of GRACE in detecting anthropogenic signals over regions with large groundwater consumption.
Skillful seasonal forecasts of Arctic sea ice retreat and advance dates in a dynamical forecast system
Authors: Sigmond M. , Reader M. C. , Flato G. M. , Merryfield W. J. , Tivy A.
Published: November 2016

The need for skillful seasonal forecasts of Arctic sea ice is rapidly increasing. Technology to perform such forecasts with coupled atmosphere‐ocean‐sea ice systems has only recently become available, with previous skill evaluations mainly limited to area‐integrated quantities. Here we show, based on a large set of retrospective ensemble model forecasts, that a dynamical forecast system produces skillful seasonal forecasts of local sea ice retreat and advance dates—variables that are of great interest to a wide range of end users. Advance dates can generally be skillfully predicted at longer lead times (~5 months on average) than retreat dates (~3 months). The skill of retreat date forecasts mainly stems from persistence of initial sea ice anomalies, whereas advance date forecasts benefit from longer time scale and more predictable variability in ocean temperatures. These results suggest that further investments in the development of dynamical seasonal forecast systems may result in significant socioeconomic benefits.
Inverse electron energy dispersion from moving auroral forms
Authors: Cameron Taylor , Knudsen David
Published: November 2016

Numerous published examples of energy‐dispersed bursts show electron energies reaching as high as several keV and decaying to lower energies over a fraction of 1 s. This signature has been interpreted by some authors as due to impulsive acceleration to a broad range of energies in a localized region and by others as the result of impulsive, dispersive Alfvén waves, in which case the acceleration takes place over an extended distance along magnetic field lines. A survey by the Suprathermal (0–350 eV) Electron Imager on the Enhanced Polar Outflow Probe (ePOP) in the topside ionosphere has produced examples of high‐to‐low (“regular”) energy dispersion, but also a smaller number of examples exhibiting low‐to‐high (“inverse”) dispersion, which to our knowledge has not been reported before. Motivated by a recent report of regular electron dispersion produced by auroral rays moving faster than the E × B drift speed, we investigate a heuristic model of electron acceleration within a region of uniform electric field parallel to B which extends a distance La along magnetic field lines. We show that in addition to a broad range of energies, this model produces inverse dispersion when the detector is less than La beneath the bottom of the acceleration region and regular dispersion for detector distances larger than La. This simple model is meant to inform future efforts to construct a more physical model of suprathermal electron acceleration within moving auroral forms and suggests that inverse dispersion indicates relative proximity to an altitude‐extended acceleration region.
Predicting electromagnetic ion cyclotron wave amplitude from unstable ring current plasma conditions
Authors: Fu Xiangrong , Cowee Misa M. , Jordanova Vania K. , Gary S. Peter , Reeves Geoffrey D. , Winske Dan
Published: November 2016

Electromagnetic ion cyclotron (EMIC) waves in the Earth's inner magnetosphere are enhanced fluctuations driven unstable by ring current ion temperature anisotropy. EMIC waves can resonate with relativistic electrons and play an important role in precipitation of MeV radiation belt electrons. In this paper, we investigate the excitation and saturation of EMIC instability in a homogeneous plasma using both linear theory and nonlinear hybrid simulations. We have explored a four‐dimensional parameter space, carried out a large number of simulations, and derived a scaling formula that relates the saturation EMIC wave amplitude to initial plasma conditions. Such scaling can be used in conjunction with ring current models like ring current‐atmosphere interactions model with self‐consistent magnetic field to provide global dynamic EMIC wave maps that will be more accurate inputs for radiation belt modeling than statistical models.
Remote sensing of mesospheric dust layers using active modulation of PMWE by high‐power radio waves
Authors: Mahmoudian A. , Mohebalhojeh A. R. , Farahani M. M. , Scales W. A. , Kosch M.
Published: November 2016

This paper presents the first study of the modulation of polar mesospheric winter echoes (PMWE) by artificial radio wave heating using computational modeling and experimental observation in different radar frequency bands. The temporal behavior of PMWE response to HF pump heating can be employed to diagnose the charged dust layer associated with mesospheric smoke particles. Specifically, the rise and fall time of radar echo strength as well as relaxation and recovery time after heater turn‐on and turnoff are distinct parameters that are a function of radar frequency. The variation of PMWE strength with PMWE source region parameters such as electron‐neutral collision frequency, photodetachment current, electron temperature enhancement ratio, dust density, and radius is considered. The comparison of recent PMWE measurements at 56 MHz and 224 MHz with computational results is discussed, and dust parameters in the PMWE generation regime are estimated. Predictions for HF PMWE modification and its connection to the dust charging process by free electrons is investigated. The possibility for remote sensing of dust and plasma parameters in artificially modified PMWE regions using simultaneous measurements in multiple frequency bands are discussed.
Nitrate source apportionment using a combined dual isotope, chemical and bacterial property, and Bayesian model approach in river systems
Authors: Xia Yongqiu , Li Yuefei , Zhang Xinyu , Yan Xiaoyuan
Published: November 2016

Nitrate (NO3−) pollution is a serious problem worldwide, particularly in countries with intensive agricultural and population activities. Previous studies have used δ15N‐NO3− and δ18O‐NO3− to determine the NO3− sources in rivers. However, this approach is subject to substantial uncertainties and limitations because of the numerous NO3− sources, the wide isotopic ranges, and the existing isotopic fractionations. In this study, we outline a combined procedure for improving the determination of NO3− sources in a paddy agriculture‐urban gradient watershed in eastern China. First, the main sources of NO3− in the Qinhuai River were examined by the dual‐isotope biplot approach, in which we narrowed the isotope ranges using site‐specific isotopic results. Next, the bacterial groups and chemical properties of the river water were analyzed to verify these sources. Finally, we introduced a Bayesian model to apportion the spatiotemporal variations of the NO3− sources. Denitrification was first incorporated into the Bayesian model because denitrification plays an important role in the nitrogen pathway. The results showed that fertilizer contributed large amounts of NO3− to the surface water in traditional agricultural regions, whereas manure effluents were the dominant NO3− source in intensified agricultural regions, especially during the wet seasons. Sewage effluents were important in all three land uses and exhibited great differences between the dry season and the wet season. This combined analysis quantitatively delineates the proportion of NO3− sources from paddy agriculture to urban river water for both dry and wet seasons and incorporates isotopic fractionation and uncertainties in the source compositions.
Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments
Authors: Danczak Robert E. , Sawyer Audrey H. , Williams Kenneth H. , Stegen James C. , Hobson Chad , Wilkins Michael J.
Published: November 2016

Riverbed microbial communities play an oversized role in many watershed ecosystem functions, including the processing of organic carbon, cycling of nitrogen, and alterations to metal mobility. The structure and activity of microbial assemblages depend in part on geochemical conditions set by river‐groundwater exchange or hyporheic exchange. To assess how seasonal changes in river‐groundwater mixing affect these populations in a snowmelt‐dominated fluvial system, vertical sediment and pore water profiles were sampled at three time points at one location in the hyporheic zone of the Colorado River and analyzed by using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling. Oxic river water penetrated deepest into the subsurface during peak river discharge, while under base flow conditions, anoxic groundwater dominated shallower depths. Over a 70 cm thick interval, riverbed sediments were therefore exposed to seasonally fluctuating redox conditions and hosted microbial populations statistically different from those at both shallower and deeper locations. Additionally, microbial populations within this zone were shown to be the most dynamic across sampling time points, underlining the critical role that hyporheic mixing plays in constraining microbial abundances. Given such mixing effects, we anticipate that future changes in river discharge in mountainous, semiarid western U.S. watersheds may affect microbial community structure and function in riverbed environments, with potential implications for biogeochemical processes in riparian regions.
Biophysical controls over concentration and depth distribution of soil organic carbon and nitrogen in desert playas
Authors: McKenna Owen P. , Sala Osvaldo E.
Published: November 2016

Playa wetlands are important areas of soil organic carbon and nutrient storage in drylands. We conducted this study to assess how catchment biophysical variables control soil organic carbon and nitrogen in playas and how playas function differently than upland ecosystems. We found that playa organic carbon and nitrogen corresponded primarily with catchment vegetation cover and secondarily with catchment area, slope, and soil texture. The effect of increased organic matter production associated with high catchment vegetation cover overshadowed the potential effect of reduced run‐on. We also found soil carbon and nitrogen profiles to be significantly shallower in playas than uplands. This trend is correlated with evidence of sedimentation and shallow‐rooted plants in playas. Upland soils had a deeper carbon and nitrogen profile, which correlated with organic matter being generated by deeply rooted vegetation. In playas, C:N ratios remained constant through depth but in uplands, C:N ratios increased through depth. We found evidence that differences in rooting depth distributions and soil texture may explain these C:N variations between uplands and playas. In uplands, clay concentration increased with depth, whereas in playas, clay concentration did not change with depth, which highlighted the important role of sedimentation in these ecosystems. Our results suggest that small changes in playa catchment vegetation cover in response to climate change or grazing intensity would greatly impact playa soil organic carbon and nitrogen stocks. This effect would be due to the playa soils dependence on allochthonous organic matter and the large upland area that drains into playas.
Variable phase propagation velocity for long‐range lightning location system
Authors: Liu Zhongjian , Koh Kuang Liang , Mezentsev Andrew , Enno Sven‐Erik , Sugier Jacqueline , Füllekrug Martin
Published: November 2016

The electromagnetic wave propagation velocity at low radio frequencies is an important input parameter for lightning location systems that use time of arrival (TOA) method. This velocity is normally fixed at or near the speed of light. However, this study finds that the radio waves from two submarine communication transmitters at 20.9 kHz and 23.4 kHz exhibit phase propagation velocities that are ~0.51% slower and ~0.64% faster than the speed of light as a result of sky wave contributions and ground effects. Therefore, a novel technique with a variable phase propagation velocity is implemented for the first time in the TOA method and applied to electric field recordings with a long‐baseline lightning location system that consists of four radio receivers in western Europe. The lightning locations inferred from variable velocities improve the accuracy of locations inferred from a fixed velocity by ~0.89–1.06 km when compared to the lightning locations reported by the UK MetOffice. The normal distributions of the observed phase propagation velocities in small geographic areas are not centered at the speed of light. Consequently, representative velocities can be calculated for many small geographic areas to produce a velocity map over central France where numerous lightning discharges occurred. This map reflects the impact of sky waves and ground effects on the calculation of lightning locations as a result of the network configuration. It is concluded that the use of variable phase propagation velocities mitigates the influence of sky waves and ground effects in long‐range lightning location networks.
Distributed Temperature Sensing as a downhole tool in hydrogeology
Authors: Bense V. F. , Read T. , Bour O. , Le Borgne T. , Coleman T. , Krause S. , Chalari A. , Mondanos M. , Ciocca F. , Selker J. S.
Published: November 2016

Distributed Temperature Sensing (DTS) technology enables downhole temperature monitoring to study hydrogeological processes at unprecedentedly high frequency and spatial resolution. DTS has been widely applied in passive mode in site investigations of groundwater flow, in‐well flow, and subsurface thermal property estimation. However, recent years have seen the further development of the use of DTS in an active mode (A‐DTS) for which heat sources are deployed. A suite of recent studies using A‐DTS downhole in hydrogeological investigations illustrate the wide range of different approaches and creativity in designing methodologies. The purpose of this review is to outline and discuss the various applications and limitations of DTS in downhole investigations for hydrogeological conditions and aquifer geological properties. To this end, we first review examples where passive DTS has been used to study hydrogeology via downhole applications. Secondly, we discuss and categorize current A‐DTS borehole methods into three types. These are thermal advection tests, hybrid cable flow logging, and heat pulse tests. We explore the various options with regards to cable installation, heating approach, duration, and spatial extent in order to improve their applicability in a range of settings. These determine the extent to which each method is sensitive to thermal properties, vertical in‐well flow, or natural gradient flow. Our review confirms that the application of DTS has significant advantages over discrete point temperature measurements, particularly in deep wells, and highlights the potential for further method developments in conjunction with other emerging hydrogeophysical tools.
Debates—Stochastic subsurface hydrology from theory to practice: Does stochastic subsurface hydrology help solving practical problems of contaminant hydrogeology?
Authors: Cirpka Olaf A. , Valocchi Albert J.
Published: November 2016

While stochastic subsurface hydrology has been tremendously successful in understanding how the spatial variability of hydraulic conductivity affects conservative solute transport in idealized settings, it has gained little impact in practice. This is the case because typical assumptions needed for the derivation of analytical expressions are too restrictive for practical applications and often geologically implausible, small‐scale variation of hydraulic conductivity is by far not the only cause of uncertainty when considering the fate and remediation of pollutants, and the research community has not developed enough methods that can directly be used by practitioners. To overcome these shortcomings, we propose putting more emphasis on providing easy‐to‐use tools to generate realistic realizations of subsurface properties that are conditioned on all data measured at a site, extending the focus from hydraulic conductivity only to all parameters and processes relevant for reactive transport, making use of self‐organizing principles of reactive transport to conceptually simplify the problem, and addressing conceptual uncertainty by stochastic methods.
Pore‐scale network modeling of microbially induced calcium carbonate precipitation: Insight into scale dependence of biogeochemical reaction rates
Authors: Qin Chao‐Zhong , Hassanizadeh S. Majid , Ebigbo Anozie
Published: November 2016

The engineering of microbially induced calcium carbonate precipitation (MICP) has attracted much attention in a number of applications, such as sealing of CO2 leakage pathways, soil stabilization, and subsurface remediation of radionuclides and toxic metals. The goal of this work is to gain insight into pore‐scale processes of MICP and scale dependence of biogeochemical reaction rates. This will help us develop efficient field‐scale MICP models. In this work, we have developed a comprehensive pore‐network model for MICP, with geochemical speciation calculated by the open‐source PHREEQC module. A numerical pseudo‐3‐D micromodel as the computational domain was generated by a novel pore‐network generation method. We modeled a three‐stage process in the engineering of MICP including the growth of biofilm, the injection of calcium‐rich medium, and the precipitation of calcium carbonate. A number of test cases were conducted to illustrate how calcite precipitation was influenced by different operating conditions. In addition, we studied the possibility of reducing the computational effort by simplifying geochemical calculations. Finally, the effect of mass transfer limitation of possible carbonate ions in a pore element on calcite precipitation was explored.
Physio‐climatic controls on vulnerability of watersheds to climate and land use change across the U. S.
Authors: Deshmukh Ankit , Singh Riddhi
Published: November 2016

Understanding how a watershed's physio‐climatic characteristics affect its vulnerability to environmental (climatic and land use) change is crucial for managing these complex systems. In this study, we combine the strengths of recently developed exploratory modeling frameworks and comparative hydrology to quantify the relationship between watershed's vulnerability and its physio‐climatic characteristics. We propose a definition of vulnerability that can be used by a diverse range of water system managers and is useful in the presence of large uncertainties in drivers of environmental change. This definition is related to adverse climate change and land use thresholds that are quantified using a recently developed exploratory modeling approach. In this way, we estimate the vulnerability of 69 watersheds in the United States to climate and land use change. We explore definitions of vulnerability that describe average or extreme flow conditions, as well as others that are relevant from the point of view of instream organisms. In order to understand the dominant controls on vulnerability, we correlate these indices with watershed's characteristics describing its topography, geology, drainage, climate, and land use. We find that mean annual flow is more vulnerable to reductions in precipitation in watersheds with lower average soil permeability, lower baseflow index, lower forest cover, higher topographical wetness index, and vice‐versa. Our results also indicate a potential mediation of climate change impacts by regional groundwater systems. By developing such relationships across a large range of watersheds, such information can potentially be used to assess the vulnerability of ungauged watersheds to uncertain environmental change.