Storage Compartment Research Articles

Numerical Simulation and Optimization of a Phase-Change Energy Storage Box in a Modular Mobile Thermal Energy Supply System

Featuring phase-change energy storage, a mobile thermal energy supply system (M-TES) demonstrates remarkable waste heat transfer capabilities across various spatial scales and temporal durations, thereby effectively optimizing the localized energy distribution structure—a pivotal contribution to the attainment of objectives such as “carbon peak” and “carbon neutral”. To heighten the efficiency of energy transfer for mobile heating, this research introduces the innovative concept of modular storage and transportation. This concept is brought to life through the development of a meticulously designed modular mobile phase-change energy storage compartment system. Employing computational fluid dynamics (CFD), an in-depth exploration into the performance of the modular M-TES container and the adapted phase-change material (PCM) is conducted. By implementing fin arrangements on the inner wall of the heat storage module, a remarkable upsurge in the liquid phase-transition rate of the phase-change material is achieved in comparison to the design lacking fins—this improvement approximating around 30%. However, it is essential to acknowledge that the augmentation in heat transfer gradually recedes with the proliferation of fins or an escalation in their height. Moreover, the integration of expanded graphite into erythritol emerges as profoundly effective in amplifying the thermal conductivity of the PCM. Notably, with the addition of a 15.2% volume fraction of expanded graphite to erythritol, the duration of heat storage experiences a drastic reduction to nearly 10% of its original duration, thereby signifying a momentous advancement in thermal performance.

Protein aggregation: A detrimental symptom or an adaptation mechanism?

Protein quality control mechanisms oversee numerous aspects of protein lifetime. From the point of protein synthesis, protein homeostasis machineries take part in folding, solubilization, and/or degradation of impaired proteins. Some proteins follow an alternative path upon loss of their solubility, thus are secluded from the cytosol and form protein aggregates. Protein aggregates differ in their function and composition, rendering protein aggregation a complex phenomenon that continues to receive plenty of attention in the scientific and medical communities. Traditionally, protein aggregates have been associated with aging and a large spectrum of protein folding diseases, such as neurodegenerative diseases, type 2 diabetes, or cataract. However, a body of evidence suggests that they may act as an adaptive mechanism to overcome transient stressful conditions, serving as a sink for the removal of misfolded proteins from the cytosol or storage compartments for machineries required upon stress release. In this review, we present examples and evidence elaborating different possible roles of protein aggregation and discuss their potential roles in stress survival, aging, and disease, as well as possible anti-aggregation interventions.

Making the Best Use of GRACE, GRACE‐FO and SMAP Data Through a Constrained Bayesian Data‐Model Integration

AbstractThe Gravity Recovery and Climate Experiment (GRACE, 2003–2017) and its Follow‐On mission GRACE‐FO (2018‐now) provide global estimates of the vertically integrated Terrestrial Water Storage Changes (TWSC). Since 2015, the Soil Moisture Active Passive (SMAP) radiometer observes global L‐band brightness temperatures, which are sensitive to near‐surface soil moisture. In this study, we introduce our newly developed Constrained Bayesian (ConBay) optimization approach to merge the TWSC of GRACE/GRACE‐FO along with SMAP soil moisture data into the ∼10 km resolution W3RA water balance model. ConBay is formulated based on two hierarchical multivariate state‐space models to (I) separate land hydrology compartments from GRACE/GRACE‐FO TWSC, and (II) constrain the estimation of surface soil water storage based on the SMAP data. The numerical implementation is demonstrated over the High Plain (HP) aquifer in the United States between 2015 and 2021. The implementation of ConBay is compared with an unconstrained Bayesian formulation, and our validations are performed against in‐situ USGS groundwater level observations and the European Space Agency (ESA)'s Climate Change Initiative (CCI) soil moisture data. Our results indicate that the single GRACE/GRACE‐FO assimilation improves particularly the groundwater compartment. Adding SMAP data to the ConBay approach controls the updates assigned to the surface storage compartments. For example, correlation coefficients between the ESA CCI and the ConBay‐derived surface soil water storage (0.8) that are considerably higher than those derived from the unconstrained experiment (−0.3) in the North HP. The percentage of updates introduced to the W3RA groundwater storage is also decreased from 64% to 57%.

Cell cycle-linked vacuolar pH dynamics regulate amino acid homeostasis and cell growth

Amino acid homeostasis is critical for many cellular processes. It is well established that amino acids are compartmentalized using pH gradients generated between organelles and the cytoplasm; however, the dynamics of this partitioning has not been explored. Here we develop a highly sensitive pH reporter and find that the major amino acid storage compartment in Saccharomyces cerevisiae, the lysosome-like vacuole, alkalinizes before cell division and re-acidifies as cells divide. The vacuolar pH dynamics require the uptake of extracellular amino acids and activity of TORC1, the v-ATPase and the cycling of the vacuolar specific lipid phosphatidylinositol 3,5-bisphosphate, which is regulated by the cyclin-dependent kinase Pho85 (CDK5 in mammals). Vacuolar pH regulation enables amino acid sequestration and mobilization from the organelle, which is important for mitochondrial function, ribosome homeostasis and cell size control. Collectively, our data provide a new paradigm for the use of dynamic pH-dependent amino acid compartmentalization during cell growth/division.

KABİN MEMURU SEÇİM KRİTERLERİNİN A380 UÇAK MODELİNE GÖRE ANTROPOMETRİK İNCELENMESİ

Airline companies use specific selection criteria for cabin crew to ensure that candidates meet their physical requirements. Some of these criteria are the height and reach distance of the candidates. This selection criterion is designed so that cabin crew can effectively perform tasks such as being able to master emergency equipment, have access to upper storage compartments and assist disabled or injured passengers. The aim of this study is to examine the height and reach distance requirements, anthropometrically according to the A380 aircraft model. The study examined anthropometric studies conducted in Qatar Airways, Singapore Airlines, Emirates, All Nippon Airways, and Qantas Airlines and provided the collection of height and reach distance data of the people in these countries under a single roof and determined the status of A380 aircraft model. As a result of the research, it is recommended that airline companies use standardized anthropometric measurement parameters in the selection of cabin crews.

The synaptic vesicle protein Mover/TPRG1L is associated with lipid droplets in astrocytes.

Crucial brain functions such as neurotransmission, myelination, and signaling pose a high demand for lipids. Lipid dysregulation is associated with neuroinflammation and neurodegeneration. Astrocytes protect neurons from lipid induced damage by accumulating and metabolizing toxic lipids in organelles called lipid droplets (LDs). LDs have long been considered as lipid storage compartments in adipocytes, but less is known about their biogenesis and composition in the brain. In particular, proteins covering the LD surface are not yet fully identified. Here, we report that the presynaptic protein Mover/TPRG1L, which regulates the probability of neurotransmitter release in neurons, is a component of the LD coat in astrocytes. Using conventional and super-resolution microscopy, we demonstrate that Mover surrounds naive and oleic acid induced astrocytic LDs. We confirm the identity of astrocytic LDs using the neutral lipid stains Bodipy and LipidTox, as well as immunofluorescence for perilipin-2, a known component of the LD coat. In astrocytes, recombinant Mover was sufficient to induce an accumulation of LDs. Furthermore, we identified point mutations that abolish targeting to LDs and show similarities in the required binding sequences for association to the presynapse and LDs. Our results show that Mover is not only a presynaptic protein but also a candidate for LD regulation. This highlights the dual role of Mover in synaptic transmission and regulation of astrocytic LDs, which may be particularly important in the context of lipid-related neurological disorders.

Phosphorylation of the N-terminus of Syntaxin-16 controls interaction with mVps45 and GLUT4 trafficking in adipocytes.

The ability of insulin to stimulate glucose transport in muscle and fat cells is mediated by the regulated delivery of intracellular vesicles containing glucose transporter-4 (GLUT4) to the plasma membrane, a process known to be defective in disease such as Type 2 diabetes. In the absence of insulin, GLUT4 is sequestered in tubules and vesicles within the cytosol, collectively known as the GLUT4 storage compartment. A subset of these vesicles, known as the 'insulin responsive vesicles' are selectively delivered to the cell surface in response to insulin. We have previously identified Syntaxin16 (Sx16) and its cognate Sec1/Munc18 protein family member mVps45 as key regulatory proteins involved in the delivery of GLUT4 into insulin responsive vesicles. Here we show that mutation of a key residue within the Sx16 N-terminus involved in mVps45 binding, and the mutation of the Sx16 binding site in mVps45 both perturb GLUT4 sorting, consistent with an important role of the interaction of these two proteins in GLUT4 trafficking. We identify Threonine-7 (T7) as a site of phosphorylation of Sx16 in vitro. Mutation of T7 to D impairs Sx16 binding to mVps45 in vitro and overexpression of T7D significantly impaired insulin-stimulated glucose transport in adipocytes. We show that both AMP-activated protein kinase (AMPK) and its relative SIK2 phosphorylate this site. Our data suggest that Sx16 T7 is a potentially important regulatory site for GLUT4 trafficking in adipocytes.

Bytový dům pro zemědělce: k procesu adaptace městských standardů bydlení v prostředí vesnických sídel

Housing construction in Czechoslovakia began to grow in the 1940s, which was reflected in the increased number of flats and improved housing standards. This growth was made possible mainly due to the construction of blocks of flats. Although in the countryside, in contrast to the cities, people predominantly lived in their own family houses, the construction of apartment blocks also contributed to the increase in capacity there. However, the experience from the 1940s and 1950s shows negative impacts of adopting the projects for blocks of flats which were designed for the city and the urban way of life and did not suit rural residents, who had different working patterns and needs. In the 1960s, an intensive dialogue between local participants, architects, and the authorities took place, leading to the adaptation of the apartment block concept to the needs of agricultural workers. The adaption concerned both the external appearance, which had to respect the village environment, and the internal layout. The adapted projects included separate rooms for residents to wash themselves after their return from fields and gardens, and storage compartments for foods and livestock feed. Attention was also paid to the surroundings, where buildings related to residents’ farming activities were designed (small animal breeding, working in the gardens and small fields). The willingness to conduct the dialogue and to adapt the projects for rural blocks of flats disappeared in the 1970s as a result of the normalization and gradual improvement in agricultural workers’ living standards.

Lipid droplets are versatile organelles involved in plant development and plant response to environmental changes.

Since decades plant lipid droplets (LDs) are described as storage organelles accumulated in seeds to provide energy for seedling growth after germination. Indeed, LDs are the site of accumulation for neutral lipids, predominantly triacylglycerols (TAGs), one of the most energy-dense molecules, and sterol esters. Such organelles are present in the whole plant kingdom, from microalgae to perennial trees, and can probably be found in all plant tissues. Several studies over the past decade have revealed that LDs are not merely simple energy storage compartments, but also dynamic structures involved in diverse cellular processes like membrane remodeling, regulation of energy homeostasis and stress responses. In this review, we aim to highlight the functions of LDs in plant development and response to environmental changes. In particular, we tackle the fate and roles of LDs during the plant post-stress recovery phase.

Mammalian Oocytes Store mRNAs in a Mitochondria-Associated Membraneless Compartment

ABSTRACT During the final stages of oocyte growth, transcription ceases only to resume following fertilization. During this cessation, the oocyte and the embryo can only use stores mRNAs to synthesize new products, meaning the storage of maternal mRNAs is critical for generating haploid eggs through meiosis and for early embryonic development. Membraneless storage compartments are well characterized in nonmammalian oocytes but are less understood in more relevant models. Studies have established that RNA-binding proteins YBX2 and ZAR1 are required for maternal mRNA storage in full-grown mouse oocytes, and this study aimed to further characterize the localization of maternal mRNAs and the mechanism that stores them. The potential colocalization between highly expressed RNA-binding proteins and different types of membrane-bound organelles in fully grown mouse oocytes was analyzed, finding the proteins ZAR1, YBX2, DDX6, LSM14B, and 4E-T colocalized with mitochondria. Similar results were found in human, porcine, and bovine oocytes. The localization domain of RNA-binding proteins around mitochondria throughout the cytoplasm was named the mitochondria-associated ribonucleoprotein domain (MARDO). Immunostaining for ZAR1 at various growth stages was performed to determine when the MARDO forms, revealing that formation is directed by an increase in mitochondrial membrane potential during oocyte growth. ZAR1 was observed to be the most highly enriched of these proteins on mitochondria and to be the promoter of MARDO coalescence and mitochondrial clustering. Injections of RNase into mouse oocytes revealed MARDO is a phase-separated compartment regulated by RNA levels, and further analysis identified the disordered N-terminal region of ZAR1 drives MARDO coalescence into a hydrogel-like matrix that sequesters mitochondria. Next, the degradation of MARDO at the meiosis stage when oocytes resume maturation was analyzed. ZAR1 was found to be progressively depleted from the mitochondria during oocyte meiotic maturation. Mass spectrometry revealed phosphorylation as a driving mechanism for this disassembly during maturation. MARDO dissolution accompanied a decrease in ZAR1 levels and occurred during the transition from MI to MII. Treating oocytes with a proteasome inhibitor blocked dissolution of MARDO, whereas impairing spindle assembly causing cell-cycle arrest before MI had no effect. This suggested that proteasome-mediated degradation of ZAR1 underlies MARDO dissolution during oocyte meiotic maturation. Knockout studies in mice confirmed that ZAR1 is essential for MARDO assembly, and in these knockouts more than 1000 mRNAs, many of which were enriched in the MARDO, were reduced by at least 50%, suggesting MARDO disruption also causes mRNA reduction. Many RNA-binding proteins in the MARDO are implicated in translational repression, and by labeling translating ribosomes assembled on mRNAs, it was seen that these active ribosomes were mostly excluded from the MARDO. In addition, ZAR1 was seen to substantially reduce the translation of bound mRNA, suggesting that the maternal mRNAs stored in the MARDO are translationally repressed. This study identified and characterized the MARDO, a mitochondria-associated membraneless compartment that stores maternal mRNAs in mouse, bovine, porcine, and human oocytes.

Neuronal Store-Operated Calcium Channels.

The endoplasmic reticulum (ER) is the major intracellular calcium (Ca2+) storage compartment in eukaryotic cells. In most instances, the mobilization of Ca2+ from this store is followed by a delayed and sustained uptake of Ca2+ through Ca2+-permeable channels of the cell surface named store-operated Ca2+ channels (SOCCs). This gives rise to a store-operated Ca2+ entry (SOCE) that has been thoroughly investigated in electrically non-excitable cells where it is the principal regulated Ca2+ entry pathway. The existence of this Ca2+ route in neurons has long been a matter of debate. However, a growing body of experimental evidence indicates that the recruitment of Ca2+ from neuronal ER Ca2+ stores generates a SOCE. The present review summarizes the main studies supporting the presence of a depletion-dependent Ca2+ entry in neurons. It also addresses the question of the molecular composition of neuronal SOCCs, their expression, pharmacological properties, as well as their physiological relevance.

Analysis of Jeffrey fluid on MHD flow with stretching – porous sheets of heat transfer system

This communication about the mathematical model of analysis of heat transfer system which as the Jeffery fluid of MHD flow with the addition of the porous-stretching sheet in the system which in the form of partial differential equation (PDE) converted into Ordinary differential equation (ODE) using Numerical methods of lie similarity and transformation technique and with shooting method. The results depict that altering the parameters of Jeffery fluid, heat source, porosity in stretching sheet and the physical properties of magnetic field in the system with increasing manner, and the changes are observed in the way of reducing the temperature in the heat convicting or transferring system and therefore, increased the convection rate in the heat transfer system. The application of the heat transfer system in industrial machines, mass cloud data storage compartments, electronic device refrigeration etc., which has necessity to improve the heating and cooling system

Mutations in Neurobeachin-like 2 do not impact Weibel-Palade body biogenesis and von Willebrand factor secretion in gray platelet syndrome Endothelial Colony Forming Cells

BackgroundPatients with gray platelet syndrome (GPS) and Neurobeachin-like 2 (NBEAL2) deficiency produce platelets lacking alpha-granules (AGs) and present with lifelong bleeding symptoms. AGs are lysosome-related organelles and store the hemostatic protein von Willebrand factor (VWF) and the transmembrane protein P-selectin. Weibel-Palade bodies (WPBs) are lysosome-related organelles of endothelial cells and also store VWF and P-selectin. In megakaryocytes, NBEAL2 links P-selectin on AGs to the SNARE protein SEC22B on the endoplasmic reticulum, thereby preventing premature release of cargo from AG precursors. In endothelial cells, SEC22B drives VWF trafficking from the endoplasmic reticulum to Golgi and promotes the formation of elongated WPBs, but it is unclear whether this requires NBEAL2. ObjectivesTo investigate a potential role for NBEAL2 in WPB biogenesis and VWF secretion using NBEAL2-deficient endothelial cells. MethodsThe interaction of SEC22B with NBEAL2 in endothelial cells was investigated by interatomic mass spectrometry and pull-down analysis. Endothelial colony forming cells were isolated from healthy controls and 3 unrelated patients with GPS and mutations in NBEAL2. ResultsWe showed that SEC22B binds to NBEAL2 in ECs. Endothelial colony forming cells derived from a patient with GPS are deficient in NBEAL2 but reveal normal formation and maturation of WPBs and normal WPB cargo recruitment. Neither basal nor histamine-induced VWF secretion is altered in the absence of NBEAL2. ConclusionsAlthough NBEAL2 deficiency causes the absence of AGs in patients with GPS, it does not impact WPB functionality in ECs. Our data highlight the differences in the regulatory mechanisms between these 2 hemostatic storage compartments.

Multiscale imaging reveals the presence of autophagic vacuoles in developing maize endosperm.

Cereal endosperm is solely devoted to the storage of proteins and starch that will be used by the embryo upon germination. The high degree of specialization of this tissue is reflected in its endomembrane system, in which ER derived protein bodies and protein storage vacuoles (PSVs) are of particular interest. In maize seeds, the main storage proteins are zeins, that form transport incompetent aggregates within the ER lumen and finally build protein bodies that bud from the ER. In contrast to the zeins, the maize globulins are not very abundant and the vacuolar storage compartment of maize endosperm is not fully described. Whereas in other cereals, including wheat and barley, the PSV serves as the main protein storage compartment, only small, globulin-containing PSVs have been identified in maize so far. We present here a multi-scale set of data, ranging from live-cell imaging to more sophisticated 3D electron microscopy techniques (SBF-SEM), that has allowed us to investigate in detail the vacuoles in maize endosperm cells, including a novel, autophagic vacuole that is present in early developmental stages.

Enhancing spatial resolution of GRACE-derived groundwater storage anomalies in Urmia catchment using machine learning downscaling methods

The Urmia lake in north-west Iran has dried up to perilously low levels in the past two decades. In this study, we investigate the drivers behind the decline in lake water level with the help of in-situ and remote sensing data. We use total water storage (TWS) changes from the gravity recovery and climate experiment (GRACE) satellite mission. TWS from GRACE includes all the water storage compartments in a column and is the only remote sensing product that can help in estimating groundwater storage (GWS) changes. The coarse spatial (approx. 300 km) resolution of GRACE does not allow us to identify local changes that may have led to the Urmia lake disaster. In this study, we tackle the poor resolution of the GRACE data by employing three machine learning (ML) methods including random forest (RF), support vector regression (SVR) and multi-layer perceptron (MLP). The methods predict the groundwater storage anomaly (GWSA), derived from GRACE, as a function of hydro-climatic variables such as precipitation, evapotranspiration, land surface temperature (LST) and normalized difference vegetation index (NDVI) on a finer scale of 0.25° × 0.25°. We found that i) The RF model exhibited highest R (0.98), highest NSE (0.96) and lowest RMSE (18.36 mm) values. ii) The RF downscaled data indicated that the exploitation of groundwater resources in the aquifers is the main driver of groundwater storage and changes in the regional ecosystem, which has been corroborated by few other studies as well. The impact of precipitation and evapotranspiration on the GWSA was found to be rather weak, indicating that the anthropogenic derivers had the most significant impact on the GWSA changes. iii) We generally observed a significant negative trend in GWSA, having also significant positive correlations with the well data. However, over regions with dam construction significant negative correlations were found.

A body composition model with multiple storage compartments for polar bears (Ursus maritimus).

Climate warming is rapidly altering Arctic ecosystems. Polar bears (Ursus maritimus) need sea ice as a platform from which to hunt seals, but increased sea-ice loss is lengthening periods when bears are without access to primary hunting habitat. During periods of food scarcity, survival depends on the energy that a bear has stored in body reserves, termed storage energy, making this a key metric in predictive models assessing climate change impacts on polar bears. Here, we developed a body composition model for polar bears that estimates storage energy while accounting for changes in storage tissue composition. We used data of dissected polar bears (n =31) to link routinely collected field measures of total body mass and straight-line body length to the body composition of individual bears, described in terms of structural mass and two storage compartments, adipose and muscle. We then estimated the masses of metabolizable proteins and lipids within these storage compartments, giving total storage energy. We tested this multi-storage model by using it to predict changes in the lipid stores from an independent dataset of wild polar bears (n = 36) that were recaptured 8-200days later. Using length and mass measurements, our model successfully predicted direct measurements of lipid changes via isotopic dilutions (root mean squared error of 14.5kg). Separating storage into two compartments, and allowing the molecular composition of storage to vary, provides new avenues for quantifying energy stores of individuals across their life cycle. The multi-storage body composition model thus provides a basis for further exploring energetic costs of physiological processes that contribute to individual survival and reproductive success. Given bioenergetic models are increasingly used as a tool to predict individual fitness and population dynamics, our approach for estimating individual energy stores could be applicable to a wide range of species.

Numerical approach to evaluate the influence of water saturation on the strength of Neogene Tuff in Utsunomiya city, Japan

Evaluation of the deformation behavior due to drying is crucial in underground construction works. Especially, geological repository for High-Level Radioactive Waste (HLW) shall be carefully selected to act as a natural barrier to prevent radioactive nuclide leaks. Uniaxial Compressive Strength (UCS) is one such governing factors when designing or selecting a suitable location for such underground storage compartments or access tunnels. Since nuclide leakage through geological repositories, intact rocks UCS will vary with the drying conditions. Hence, it is vital to evaluate the behavior of UCS subject to the conditions prescribed. A variety of statistical models has been built to govern the interdependency between UCS and water content. However, there are no significant amount of research have been conducted to emphasize the UCS variation with the degree of saturation under the influence of drying condition. Numerically, Richard’s equation exact solution in Neuman boundary condition has been derived to exploit the degree of saturation with respect to time and position. Experimentally, obtain the UCS variation with the degree of saturation pertaining to the Neogene Tuff in Utsunomiya city, Japan. A best fit statistical model was generated for experimental data between UCS variation and the degree of saturation. Then, the experimental saturation degree was replaced by Richard’s equation exact solution saturation degree values. Surprisingly, produced graphs for experimental data and numerical analysis data for exact solution were perfectly overlapped. Results point out that change of UCS shows similar characteristics, which exponentially decrease, with both experimental saturation values and exact solution saturation values influenced the drying condition. Moreover, it suggests that UCS value can be predicted subject to the time and position in the sedimentary rocks under drying conditions.

ADDITIVELY MANUFACTURED GREEN PROPELLANT TANKS: VOLUME EFFICIENT DESIGNS AND MATERIALS CHEMICAL COMPATIBILITY

The propellant storage compartments (propellant tanks) have undergone noted evolution in the design nature (mainly the shape and the structural properties) as well as the development process. To achieve high system performance for a given propulsion system, inert mass reduction as well as efficient volume utilization can be considered as the main attributes to concern the designer. Additive manufacturing (AM) techniques, on the other hand, have played a major role in recent years in altering the propulsion system design process to achieve higher overall propulsion performance due to the technical advantages of AM in reducing mass, enhancing heat transfer through enabling complex geometries and using high performance alloys. With new chances of increasing propulsion performance come new challenges on using AM propellant tanks, and chemical compatibility with green propellants is one. The relevant chemical properties of several green energetic ionic monopropellants are addressed, as well as an assessment of their compatibility with the main materials used in AM processes. This article is published with the permission of the authors granted to 3AF; Association Aeronautique et Astronautique de France (www.3AF.fr) organizer of the Space Propulsion International Conference.

Shallow and Deep Electric Structures in the Tolhuaca Geothermal System (S. Chile) Investigated by Magnetotellurics

The geoelectric properties of the geothermal system associated with the Tolhuaca volcano were investigated by three-dimensional (3D) inversion of magnetotelluric (MT) data. This study presents the first resistivity model of the Tolhuaca volcano derived from 3D MT inversion to have a better understanding of its magmatic and hydrothermal system. We selected data from 54 MT stations for 3D inversion. We performed a series of 3D MT inversion tests by changing the type of data to be inverted, as well as the starting model to obtain a model in agreement with the geology. The final 3D MT model presents a conductive body (<20 Ωm) located 2 km below the summit of Tolhuaca volcano, inferred as a shallow magmatic storage compartment. We also distinguish a ~300 m thick layer of high conductivity (<10 Ωm) corresponding to argillic hydrothermal alteration. The MT model includes two resistive bodies (~200 Ωm) in the upper crust below the laterally displaced argillic alteration layer to the west beneath the extinct Tolhuaca, which would correspond to a shallow reservoir (~1000 m from the surface) and a deep reservoir (>1800 m from the surface) that had so far not been identified by previous resistivity models. The result of this study provides new insights into the complexity of the Tolhuaca geothermal system.

Towards a hydrogeomorphological understanding of proglacial catchments: an assessment of groundwater storage and release in an Alpine catchment

Abstract. Proglacial margins form when glaciers retreat and create zones with distinctive ecological, geomorphological and hydrological properties in Alpine environments. There is extensive literature on the geomorphology and sediment transport in such areas as well as on glacial hydrology, but there is much less research into the specific hydrological behavior of the landforms that develop after glacier retreat in and close to proglacial margins. Recent reviews have highlighted the presence of groundwater stores even in such rapidly draining environments. Here, we describe the hydrological functioning of different superficial landforms within and around the proglacial margin of the Otemma glacier, a temperate Alpine glacier in the Swiss Alps; we characterize the timing and amount of the transmission of different water sources (rain, snowmelt, ice melt) to the landforms and between them, and we compare the relationship between these processes and the catchment-scale discharge. The latter is based upon a recession-analysis-based framework. In quantifying the relative groundwater storage volumes of different superficial landforms, we show that steep zones only store water on the timescale of days, while flatter areas maintain baseflow on the order of several weeks. These landforms themselves fail to explain the catchment-scale recession patterns; our results point towards the presence of an unidentified storage compartment on the order of 40 mm, which releases water during the cold months. We suggest attributing this missing storage to deeper bedrock flowpaths. Finally, the key insights gained here into the interplay of different landforms as well as the proposed analysis framework are readily transferable to other similar proglacial margins and should contribute to a better understanding of the future hydrogeological behavior of such catchments.