Temporal Record Research Articles

Proximity-gated X-ray framing camera with gain uniformity

A novel proximity gated microchannel plate (MCP) framing camera has been designed and tested. The camera system consists of two basic components with a traveling wave microstrip photocathode gated proximity focusing X-ray image tube framing and electrical control system. The voltage of the phosphor screen, the strobe pulse of the MCP and the bias voltage of the MCP are all provided by the electronic control unit. The photocathode of image-converted tube consists of Au.Four line cathodes with a width of 12 mm and an interval of 4 mm are deposited onto the illuminated side of MCP. The camera's temporal record length is ∼1.5 ns. When the cathode is applied by a pulse with full width at half maximum of 190 ps and amplitude of -2.5 kV with -100 V bias, the temporal resolution is measured to be ∼62 ps. The gain uniformity of the cathode was characterized using a short X-ray pulse produced by a laser beam focused on a copper target. The results show that the MCP gain decreases by about 28% along the pulse direction, while the gain change perpendicular to the strip direction is within 5%.

Ichnofauna from the Silurian–Devonian beds of the Parnaíba Basin at Poti River Canyon (Piauí State, NE Brazil)

This paper characterizes the ichnology and sedimentology of the Lower Paleozoic Parnaíba Basin beds exposed in the Poti River Canyon (Piauí State, NE Brazil) and discusses the paleoenvironmental significance of the ichnofauna. The sedimentary succession represents the Silurian–Devonian infill of the Parnaíba Basin and comprises mouth bar deposits (Ipu Formation) and shoreface deposits (Tianguá and Pimenteira formations). The Silurian ichnofauna is represented by Heimdallia isp. in the topmost beds of the Ipu Formation, and Musculopodus sedentarius, Didymaulichnus lyelli, Didymaulyponomos rowei, Diplocraterion isp., Heimdallia isp., Lockeia siliquaria, Nereites irregularis, Palaeophycus tubularis, and Thalassinoides cf. horizontalis in the Tianguá Formation. The Devonian ichnofauna occurs in the Pimenteira Formation and is represented by Beaconites antarcticus, Bifungites munizi, Bifungites crucifomis, Nereites isp., and Rhizocorallium commune. Horizontal burrows and furrows occupying shallow and middle tiers dominate the ichnofauna, suggesting proximal expressions of the Cruziana ichnofacies. The predominance of sandy, unbioturbated, storm-generated beds in the shoreface deposits indicates a high frequency of storm surges in shallower areas of the shelf, which often inhibited or frequently erased most of the post-event substrate colonization record. Thus, the trace fossil in the analyzed succession represents substrate colonization below the low-tide base and above the storm wave base in shoreface settings. The presence of Musculopodus sedentarius in this assemblage expands the geographic and temporal record of the ichnogenus. The similar composition of the trace fossil assemblage with other Lower Paleozoic ichnofaunas reinforces ichnostratigraphic correlations represented in coeval Gondwanan units.

Dryophthorinae (Coleoptera: Curculionidae) in the Collection of the Museu Paraense Emílio Goeldi: inventory and type specimens

This paper reports the results of the curation of specimens of Dryophthorinae (Coleoptera: Curculionidae) housed in the Entomological Collection of the Museu Paraense Emílio Goeldi (MPEG), Belém, state of Pará, Brazil. The Collection holds a total of 1,071 specimens, with 90% of them previously unidentified. We reviewed all specimens and identified them to species level, resulting in 16 genera and 32 species of Dryophthorinae. These include the type specimens of three species: Cyrtomasius marluciae Vanin, 1998; Foveolus maculatus O’Brien, 2003; and Paramasius cristulatus Vanin, 1998. The genus Rhodobaenus Le Conte, 1876 was recorded for the first time to Brazilian Amazon. All specimen data were digitized and are now publicly available. Currently, 50% of the richness of the Dryophthorinae recorded from Brazilian Amazon is present in the Collection. The occurrence and the species richness of the Dryophthorinae examined are shown on a map. All labels contents and remarks to type material are presented. High resolution photographs of the primary types are also provided. The material examined represents a temporal and spatial record of Amazonian Dryophthorinae.

Composite development and stratigraphy of the Onepoto maar lake sediment sequence (Auckland Volcanic Field, New Zealand)

Abstract. The accurate and precise reconstruction of Quaternary climate as well as the events that punctuate it is an important driver of the study of lake sediment archives. However, until recently lake sediment-based palaeoclimate reconstructions have largely concentrated on Northern Hemisphere lake sequences due to a scarcity of continuous and high-resolution lake sediment sequences from the Southern Hemisphere, especially from the southern mid-latitudes. In this context, the deep maar lakes of the Auckland Volcanic Field of northern New Zealand are significant as several contain continuous and well-laminated sediment sequences. Onepoto Basin potentially contains the longest temporal lake sediment record from the Auckland Volcanic Field (AVF), spanning from Marine Isotope Stage 6e (MIS 6e) to the early Holocene when lacustrine sedimentation was terminated by marine breach of the south-western crater tuff ring associated with post-glacial sea-level rise. The Onepoto record consists of two new, overlapping cores spanning ca. 73 m combined with archive material in a complete composite stratigraphy. Tephrochronology and 14C dating provide the fundamental chronological framework for the core, with magnetic relative palaeo-intensity variability downcore, and meteoric 10Be influx into the palaeolake to refine the chronology. The µ-XRF (micro X-ray fluorescence) downcore variability for the entirety of the lake sediment sequence has been established with measurement of a range of proxies for climate currently underway. This work will produce the first continuous record of the last 200 kyr of palaeoclimate from northern New Zealand to date.

Submerged landscapes, marine transgression and underwater shell middens: Comparative analysis of site formation and taphonomy in Europe and North America

Shell middens, sometimes in the form of mounds of great size, are a ubiquitous indicator of coastal settlement and exploitation of marine resources across the world. However, shell middens are relatively rare before the mid-Holocene because most palaeoshorelines before that time are now submerged by sea-level rise since the Last Glacial Maximum (LGM). Previously reported examples of underwater shell middens are almost unknown and of uncertain status, and it has generally been assumed that such deposits would not survive the destructive impact of sea-level rise or would be indistinguishable from natural shell deposits. Recently, two examples of underwater shell deposits have been independently discovered and verified as anthropogenic midden deposits – a Mesolithic shell midden on the island of Hjarnø in the Straits of Denmark, and a Middle to Late Archaic shell midden in the Econfina Channel of the Gulf of Mexico, Florida, USA. We report the comparative geoarchaeological analysis of these deposits, using a sedimentological approach to unravel their formation history and post-depositional transformation. Despite the differences in coastal geomorphology and geology, cultural context, molluscan taxonomy and preservation conditions between these sites, the results demonstrate similar sedimentological profiles that are distinctive of anthropogenic deposits, demonstrate their origin as subaerial deposits at the shore edge before inundation by sea-level rise, and show that these properties can be identified in sediment samples recovered from coring. These findings support arguments that such sites likely exist in greater numbers than previously assumed, that they can be identified from minimally invasive techniques without the need for extensive underwater excavation, and that they should be sought to fill critical gaps in the temporal and geographical record concerning Late Quaternary human use of coastal zones and marine resources.

Malaria trends in Ethiopian highlands track the 2000 \u2018slowdown\u2019 in global warming

A counterargument to the importance of climate change for malaria transmission has been that regions where an effect of warmer temperatures is expected, have experienced a marked decrease in seasonal epidemic size since the turn of the new century. This decline has been observed in the densely populated highlands of East Africa at the center of the earlier debate on causes of the pronounced increase in epidemic size from the 1970s to the 1990s. The turnaround of the incidence trend around 2000 is documented here with an extensive temporal record for malaria cases for both Plasmodium falciparum and Plasmodium vivax in an Ethiopian highland. With statistical analyses and a process-based transmission model, we show that this decline was driven by the transient slowdown in global warming and associated changes in climate variability, especially ENSO. Decadal changes in temperature and concurrent climate variability facilitated rather than opposed the effect of interventions.

New horseshoe crab fossil from Germany demonstrates post-Triassic extinction of Austrolimulidae

AbstractHorseshoe crabs within Austrolimulidae represent the extreme limits to which the xiphosuridBauplancould be modified. Recent interest in this group has uncovered an unprecedented diversity of these odd-ball xiphosurids and led to suggestions that Austrolimulidae arose during the Permian Period and had become extinct by the end of the Triassic Period. Here, we extend the temporal record of Austrolimulidae by documenting a new horseshoe crab from the Lower Jurassic (Hettangian) Bayreuth Formation,Franconiolimulus pochankeigen. et sp. nov. The novel specimen displays hypertrophied genal spines, a key feature indicative of Austrolimulidae, but does not show as prominent accentuation or reduction of other exoskeletal sections. In considering the interesting family, we explore the possible origins and explanations for the bizarre morphologies exhibited by the Austrolimulidae and present hypotheses regarding the extinction of the group. Further examination of horseshoe crab fossils with unique features will undoubtedly continue to increase the diversity and disparity of these curious xiphosurids.

The rhythms of the night: increase in online night activity and emotional resilience during the spring 2020 Covid-19 lockdown

ContextThe lockdown orders established in multiple countries in response to the Covid-19 pandemic are arguably one of the most widespread and deepest shock experienced by societies in recent years. Studying their impact trough the lens of social media offers an unprecedented opportunity to understand the susceptibility and the resilience of human activity patterns to large-scale exogenous shocks. Firstly, we investigate the changes that this upheaval has caused in online activity in terms of time spent online, themes and emotion shared on the platforms, and rhythms of content consumption. Secondly, we examine the resilience of certain platform characteristics, such as the daily rhythms of emotion expression.DataTwo independent datasets about the French cyberspace: a fine-grained temporal record of almost 100 thousand YouTube videos and a collection of 8 million Tweets between February 17 and April 14, 2020.FindingsIn both datasets we observe a reshaping of the circadian rhythms with an increase of night activity during the lockdown. The analysis of the videos and tweets published during lockdown shows a general decrease in emotional contents and a shift from themes like work and money to themes like death and safety. However, the daily patterns of emotions remain mostly unchanged, thereby suggesting that emotional cycles are resilient to exogenous shocks.

Multimodal in vivo recording using transparent graphene microelectrodes illuminates spatiotemporal seizure dynamics at the microscale

Neurological disorders such as epilepsy arise from disrupted brain networks. Our capacity to treat these disorders is limited by our inability to map these networks at sufficient temporal and spatial scales to target interventions. Current best techniques either sample broad areas at low temporal resolution (e.g. calcium imaging) or record from discrete regions at high temporal resolution (e.g. electrophysiology). This limitation hampers our ability to understand and intervene in aberrations of network dynamics. Here we present a technique to map the onset and spatiotemporal spread of acute epileptic seizures in vivo by simultaneously recording high bandwidth microelectrocorticography and calcium fluorescence using transparent graphene microelectrode arrays. We integrate dynamic data features from both modalities using non-negative matrix factorization to identify sequential spatiotemporal patterns of seizure onset and evolution, revealing how the temporal progression of ictal electrophysiology is linked to the spatial evolution of the recruited seizure core. This integrated analysis of multimodal data reveals otherwise hidden state transitions in the spatial and temporal progression of acute seizures. The techniques demonstrated here may enable future targeted therapeutic interventions and novel spatially embedded models of local circuit dynamics during seizure onset and evolution.

A temporal record of microplastic pollution in Mediterranean seagrass soils.

Plastic pollution is emerging as a potential threat to the marine environment. In the current study, we selected seagrass meadows, known to efficiently trap organic and inorganic particles, to investigate the concentrations and dynamics of microplastics in their soil. We assessed microplastic contamination and accumulation in 210Pb dated soil cores collected in Posidonia oceanica meadows at three locations along the Spanish Mediterranean coast, with two sites located in the Almería region (Agua Amarga and Roquetas) and one at Cabrera Island (Santa Maria). Almería is known for its intense agricultural industry with 30000ha of plastic-covered greenhouses, while the Cabrera Island is situated far from urban areas. Microplastics were extracted using enzymatic digestion and density separation. The particles were characterized by visual identification and with Fourier-transformed infrared (FTIR) spectroscopy, and related to soil age-depth chronologies. Our findings showed that the microplastic contamination and accumulation was negligible until the mid-1970s, after which plastic particles increased dramatically, with the highest concentrations of microplastic particles (MPP) found in the recent (since 2012) surface soil of Agua Amarga (3819 MPP kg-1), followed by the top-most layers of the soil of the meadows in Roquetas (2173kg-1) and Santa Maria (68-362kg-1). The highest accumulation rate was seen in the Roquetas site (8832 MPP m-2 yr-1). The increase in microplastics in the seagrass soil was associated to land-use change following the intensification of the agricultural industry in the area, with a clear relationship between the development of the greenhouse industry in Almería and the concentration of microplastics in the historical soil record. This study shows a direct linkage between intense anthropogenic activity, an extensive use of plastics and high plastic contamination in coastal marine ecosystems such as seagrass meadows. We highlight the need of proper waste management to protect the coastal environment from continuous pollution.

Morphological abnormalities in Acartia lilljeborgii Giesbrecht (1889) (Copepoda, Calanoida) in a tropical estuary under industrial development

Morphological abnormalities in crustaceans have been registered and several are attributed to pollution and others anthropogenic activities. This study reports for the first time a temporal record of the amount and variety of morphological abnormalities in Acartia lilljeborgii, in an impacted neotropical estuary. The specimens were obtained from Suape port area, Northeast Brazil, between May 2009 and September 2010 using a 300 µm plankton net. Seven types of abnormalities were observed in one of the terminal spines of the prosome, but no temporal variation of abnormalities was found in our study. The deformities were registered in 85.7% of samples and they were found in up to 10% of the individuals (3.2 ± 2.9%). The proportion of females with abnormalities was greater than for males, in opposite to most previous reports. Due to its high distribution and abundance in part of the neotropical Atlantic coastal area, A. lilljeborgii has the potential to be used as a bioindicator of environmental conditions, although the reasons of the abnormality occurrences should be accurately investigated.

Temporal record and spatial distribution of fire foci in State of Minas Gerais, Brazil

The objectives of this study are: (i) to evaluate the space-temporal variability of fire foci by environmental satellites, CHIRPS and remote sensing products based on applied statistics, and (ii) to identify the relational pattern between the distribution of fire foci and the environmental, meteorological, and socioeconomic variables in the mesoregions of Minas Gerais (MG) - Brazil. This study used a time series of fire foci from 1998 to 2015 via BDQueimadas. The temporal record of fire foci was evaluated by Mann-Kendall (MK), Pettitt (P), Shapiro-Wilk (SW), and Bartlett (B) tests. The spatial distribution by burned area (MCD64A1-MODIS) and the Kernel density - (radius 20 km) were estimated. The environmental variables analyzed were: rainfall (mm) and maximum temperature (°C), besides proxies to vegetation canopy: NDVI, SAVI, and EVI. PCA was applied to explain the interaction between fire foci and demographic, environmental, and geographical variables for MG. The MK test indicated a significant increasing trend in fire foci in MG. The SW and B tests were significant for non-normality and homogeneity of data. The P test pointed to abrupt changes in the 2001 and 2002 cycles (El Niño and La Niña moderated), which contributes to the annual increase and in winter and spring, which is identified by the Kernel density maps. Burned areas highlighted the northern and northwestern regions of MG, Triângulo Mineiro, Jequitinhonha, and South/Southwest MG, in the 3rd quarter (increased 17%) and the 4th quarter (increased 88%). The PCA resulted in three PCs that explained 71.49% of the total variation. The SAVI was the variable that stood out, with 11.12% of the total variation, followed by Belo Horizonte, the most representative in MG. We emphasize that the applied conceptual theoretical model defined here can act in the environmental management of fire risk. However, public policies should follow the technical-scientific guidelines in the mitigation of the resulting socioeconomic - environmental damages.

High-resolution, long-term isotopic and isotopologue variation identifies the sources and sinks of methane in a deep subsurface carbon cycle

This study applies a combined isotope and doubly-substituted isotopologue (‘clumped’) methane approach to samples collected over a 9-year long-term experiment at the Kidd Creek scientific observatory located 2.4 and 2.9 km depth below surface, combined with previously published data from 2.1 km below surface. The observatory is located in a fractured rock system within Kidd Creek Mine in Timmins, Ontario, Canada, situated within a 2.7 Ga Volcanogenic Massive Sulphide (VMS) deposit on the Canadian Shield. Isotope and isotopologue methane data suggest a temporal variation in the various sources of methane within the fracture fluids system between 2.1 and 2.9 km below surface. Predominantly abiogenic methane is identified in samples collected from the deepest level of the mine (2.9 km). Comparing new data from the 2.4 km level with previous data from 2.1 km suggests addition of a small component of microbially-generated methane to the fracture water systems at 2.4 km. The temporal evolution of the methane isotopologue signatures suggest an additional process is occurring within these waters. Specifically, methane in samples from 2.4 km (and some from 2.9 km) approach low-temperature thermodynamic equilibrium in clumped isotopologue space, which is not consistent with kinetically-controlled methane production (either microbial or abiogenic). Anaerobic Oxidation of Methane (AOM) during microbial methanotrophy is shown to be the most likely process to drive such re-equilibration via isotopic bond re-ordering. This study provides an unprecedented high-resolution temporal record over more than a decade for methane in a deep subsurface crystalline environment and demonstrates the advantages of clumped isotopologue studies to identify multiple processes controlling the methane cycle in these systems including both abiotic and biotic methane production and methanotrophy.

Extreme wave events and sampling variability

Wave field data are affected not only by the accuracy of instruments recording them but also by sampling variability, an uncertainty due to the limited number of observations. For stationary meteorological conditions, due to the randomness of the sea surface elevation, wave parameters derived from a temporal or spatial wave record will depend on which part of a wave record is used in an analysis as well as on the length of a wave record and/or size of the investigated ocean area. This study demonstrates, using numerical simulations, challenges that sampling variability brings in the interpretation of nonlinear wave characteristics of the surface elevation when single 20- or 30-min field wave records are used in an analysis. As examples, we use sea states in which rogue waves were observed in the North Sea and investigate them using linear, second-, and third-order numerical simulations. The third-order wave data are simulated by a numerical solver based on the higher order spectral method (HOSM) which includes the leading order nonlinear dynamical effects, accounting for the effect of modulational instability. Wave steepness, the maximum wave crest, skewness, and kurtosis are investigated in unidirectional and directional wave fields. The study shows that having a single 20- or 30-min wave record may make it difficult to determine on the degree of wave field nonlinearity and the accuracy of derived wave parameters, as well as to evaluate the validity of wave models. Both single-point temporal and stereo-video camera data are discussed. We demonstrate that numerical simulations represent important supporting tools for wave field measurements.

The internal structure and geodynamics of Mars inferred from a 4.2-Gyr zircon record.

Combining U-Pb ages with Lu-Hf data in zircon provides insights into the magmatic history of rocky planets. The Northwest Africa (NWA) 7034/7533 meteorites are samples of the southern highlands of Mars containing zircon with ages as old as 4476.3 ± 0.9 Ma, interpreted to reflect reworking of the primordial Martian crust by impacts. We extracted a statistically significant zircon population (n = 57) from NWA 7533 that defines a temporal record spanning 4.2 Gyr. Ancient zircons record ages from 4485.5 ± 2.2 Ma to 4331.0 ± 1.4 Ma, defining a bimodal distribution with groupings at 4474 ± 10 Ma and 4442 ± 17 Ma. We interpret these to represent intense bombardment episodes at the planet's surface, possibly triggered by the early migration of gas giant planets. The unradiogenic initial Hf-isotope composition of these zircons establishes that Mars's igneous activity prior to ∼4.3 Ga was limited to impact-related reworking of a chemically enriched, primordial crust. A group of younger detrital zircons record ages from 1548.0 ± 8.8 Ma to 299.5 ± 0.6 Ma. The only plausible sources for these grains are the temporally associated Elysium and Tharsis volcanic provinces that are the expressions of deep-seated mantle plumes. The chondritic-like Hf-isotope compositions of these zircons require the existence of a primitive and convecting mantle reservoir, indicating that Mars has been in a stagnant-lid tectonic regime for most of its history. Our results imply that zircon is ubiquitous on the Martian surface, providing a faithful record of the planet's magmatic history.

Conjunctive representation of what and when in monkey hippocampus and lateral prefrontal cortex during an associative memory task.

Adaptive memory requires the organism to form associations that bridge between events separated in time. Many studies show interactions between hippocampus (HPC) and prefrontal cortex (PFC) during formation of such associations. We analyze neural recording from monkey HPC and PFC during a memory task that requires the monkey to associate stimuli separated by about a second in time. After the first stimulus was presented, large numbers of units in both HPC and PFC fired in sequence. Many units fired only when a particular stimulus was presented at a particular time in the past. These results indicate that both HPC and PFC maintain a temporal record of events that could be used to form associations across time. This temporal record of the past is a key component of the temporal coding hypothesis, a hypothesis in psychology that memory not only encodes what happened, but when it happened.

Emperical Analysis of Noise Pollution in Nigeria Cities; Acase Study of Bida, Nigeria

The findings from various research efforts have linked the incidence of different health issues to excessive noise pollution in all works of life. This study provides empirical analysis of the effects of noise pollution on the well-being of the residents of Bida Local Government Area, Niger State, Nigeria. The study adopted a case study research design, involving cross-sectional procedure. Field observations and medical reports were obtained to support the respondents’ perception on the state of their well-being. The sample size for the study was selected using the housing stock in the various wards. One major street in each ward was selected. A total of 1,833 buildings were counted along the sampled streets and 10% of this was selected for the administration of structured questionnaire. The environmental quality of the wards was determined by measuring the noise level using Testo 815 noise meters. The result revealed that Bariki ward which houses the GRA has the lowest noise level of 37.8 dB(A)while the noise pollution levels recorded in the other thirteen wards were all above the recommended levels. The average ambient noise level in sawmills, commercial centres, road junctions and industrial areas were above 90 dB(A). The temporal record from the Federal Medical Centre, Bida revealed that, apart from malaria, hypertension (5,614 outpatients) was the most prevalent health issue in 2013 alone. The paper emphasised the need for compatibility consideration in the choice of residential location, the use of ear muffler and effective enforcement of zoning regulations. Key words: Noise, Environmental quality, Bida, Well-being, Decibels

CDP-choline and galantamine, a personalized α7 nicotinic acetylcholine receptor targeted treatment for the modulation of speech MMN indexed deviance detection in healthy volunteers: a pilot study.

The combination of CDP-choline, an α7 nicotinic acetylcholine receptor (α7 nAChR) agonist, with galantamine, a positive allosteric modulator of nAChRs, is believed to counter the fast desensitization rate of the α7 nAChRs and may be of interest for schizophrenia (SCZ) patients. Beyond the positive and negative clinical symptoms, deficits in early auditory prediction-error processes are also observed in SCZ. Regularity violations activate these mechanisms that are indexed by electroencephalography-derived mismatch negativity (MMN) event-related potentials (ERPs) in response to auditory deviance. This pilot study in thirty-three healthy humans assessed the effects of an optimized α7 nAChR strategy combining CDP-choline (500 mg) with galantamine (16 mg) on speech-elicited MMN amplitude and latency measures. The randomized, double-blinded, placebo-controlled, and counterbalanced design with a baseline stratification method allowed for assessment of individual response differences. Increases in MMN generation mediated by the acute CDP-choline/galantamine treatment in individuals with low baseline MMN amplitude for frequency, intensity, duration, and vowel deviants were revealed. These results, observed primarily at temporal recording sites overlying the auditory cortex, implicate α7 nAChRs in the enhancement of speech deviance detection and warrant further examination with respect to dysfunctional auditory deviance processing in individuals with SCZ.

2,200-Year tree-ring and lake-sediment based snowpack reconstruction for the northern Rocky Mountains highlights the historic magnitude of recent snow drought

In recent decades, Rocky Mountain accumulated snowpack levels have experienced rapid declines, yet long-term records of snowpack prior to the installation of snowpack observation stations in the early and mid 20th century are limited. To date, a small number of tree-ring based reconstructions of April 1 Snow Water Equivalent (SWE) in the northern Rocky Mountains have extended modern records of snowpack variability to ∼1200 C.E. Carbonate isotope lake sediment records, provide an opportunity to further extend tree-ring based reconstructions through the Holocene, providing a millennial-scale temporal record that allows for an evaluation of multi-scale drivers of snowpack variability, from internal climate dynamics to orbital-scale forcings. Here we present a ∼2200 year preliminary reconstruction of northern Rockies snowpack based on δ18O measurements of sediment carbonates collected from Foy Lake, Montana. We explore the statistical calibration of lake sediment δ18O to an annually resolved snowpack reconstruction from tree rings, and develop an approach to assess and quantify potential sources of error in this reconstruction approach. The sediment-based snowpack reconstruction shows strong low-frequency variability in snowpack over the last two millennia with few snow droughts approaching the magnitude of recent snowpack declines. Given the growing availability of high-resolution, carbonate-rich lake sediment records, such reconstructions could help improve our understanding of how snowpack conditions varied under previous climatic events (mid-Holocene climate optimum ca. 9−6 ka), providing critical insights for anticipating future snowpack conditions.

Graph Neural Network-Based Diagnosis Prediction.

Diagnosis prediction is an important predictive task in health care that aims to predict the patient future diagnosis based on their historical medical records. A crucial requirement for this task is to effectively model the high-dimensional, noisy, and temporal electronic health record (EHR) data. Existing studies fulfill this requirement by applying recurrent neural networks with attention mechanisms, but facing data insufficiency and noise problem. Recently, more accurate and robust medical knowledge-guided methods have been proposed and have achieved superior performance. These methods inject the knowledge from a graph structure medical ontology into deep models via attention mechanisms to provide supplementary information of the input data. However, these methods only partially leverage the knowledge graph and neglect the global structure information, which is an important feature. To address this problem, we propose an end-to-end robust solution, namely Graph Neural Network-Based Diagnosis Prediction (GNDP). First, we propose to utilize the medical knowledge graph as an internal information of a patient by constructing sequential patient graphs. These graphs not only carry the historical information from the EHR but also infuse with domain knowledge. Then we design a robust diagnosis prediction model based on a spatial-temporal graph convolutional network. The proposed model extracts meaningful features from sequential graph EHR data effectively through multiple spatial-temporal graph convolution units to generate robust patients' representations for accurate diagnosis predictions. We evaluate the performance of GNDP against a set of state-of-the-art methods on two real-world medical data sets, the results demonstrate that our methods can achieve a better utilization of knowledge graph and improve the accuracy on diagnosis prediction tasks.