Unlimited Sampling Research Articles

A score-based filter for nonlinear data assimilation

We propose a score-based generative sampling method for solving the nonlinear filtering problem with superior accuracy. A major drawback of existing nonlinear filtering methods, e.g., particle filters, is the low accuracy in handling high-dimensional nonlinear problems. To overcome this issue, we incorporate the score-based diffusion model into the recursive Bayesian filter framework to develop a novel score-based filter (SF). The key idea of SF is to store the information of the recursively updated filtering density function in the score function, instead of storing the information in a set of finite Monte Carlo samples (used in particle filters and ensemble Kalman filters). By leveraging the reverse-time diffusion process, SF can generate unlimited samples to characterize the filtering density. An essential aspect of SF is its analytical update step, gradually incorporating data information into the score function. This step is crucial in mitigating the degeneracy issue faced when dealing with very high-dimensional nonlinear filtering problems. Three benchmark problems are used to demonstrate the performance of our method. In particular, SF provides surprisingly impressive performance in reliably capturing/tracking the 100-dimensional stochastic Lorenz system that is a well-known challenging problem for existing filtering methods.

Modeling the Temperature-Dependent Size Change of Polydisperse Nano-objects using a Deep Generative Model.

Modern microscopy techniques can be used to investigate soft nano-objects at the nanometer scale. However, time-consuming microscopy measurements combined with low numbers of observable polydisperse objects often limit the statistics. We propose a method for identifying the most representative objects from their respective point clouds. These point cloud data are obtained, for example, through the localization of single emitters in super-resolution fluorescence microscopy. External stimuli, such as temperature, can cause changes in the shape and properties of adaptive objects. Due to the demanding and time-consuming nature of super-resolution microscopy experiments, only a limited number of temperature steps can be performed. Therefore, we propose a deep generative model that learns the underlying point distribution of temperature-dependent microgels, enabling the reliable generation of unlimited samples with an arbitrary number of localizations. Our method greatly cuts down the data collection effort across diverse experimental conditions, proving invaluable for soft condensed matter studies.

Automated solid phase DNA extraction on a lab-on-a-disc with two-degrees of freedom instrumentation

BackgroundLab-on-a-disc (LoaD) technology has emerged as a transformative approach for point-of-care diagnostics and high-throughput testing. The promise of integrating multiple laboratory functions onto a single integrated platform has significant implications for healthcare, especially in resource-limited settings. However, one of the primary challenges faced in the design and manufacture of LoaD devices is the integration of effective valving mechanisms. These valves are essential for fluid control and routing, but their intricacy often leads to complexities in design and increased vulnerability to failure. This emphasizes the need for improved designs and manufacturing processes without complex, integrated valving mechanisms. (96) ResultsWe describe a fully automated biological workflow and reagent actuation on a LoaD device without an integrated valving system. The Two Degrees-of-Freedom (2DoF) custom centrifuge alters the centre of rotation, facilitating fluid flow direction changes on the microfluidic platform through a custom programmed interface. A novel 360-degree fluid manipulation approach via secondary planetary gear motion enabled sequential assay reagent actuation without embedded valve triggering, with the addition of infinite incubation times and efficient use of platform realty. The simplified LoaD platform uses clever design, with intermediate flow chambers to avoid cross contamination between reagent steps. Notably, the optimized LoaD platform demonstrated a two-fold DNA yield at higher HEK-293 cell concentrations compared to commercially available spin-column kits. This significantly simplified LoaD platform successfully automated a common, complex workflow without inhibiting DNA purification. (129) SignificanceThis system exhibits the clever coupling of both 2DoF and centrifugal microfluidics to create an autonomous testing package capable of eradicating the need for complex valving systems to automate biological workflows on LoaDs. This automated system has outperformed commercially available DNA extraction kits for higher cell counts. The platform's elimination of valve requirements ensures unlimited sample incubation times and enhances reliability, making it a straightforward option for automated biological workflows, particularly in diagnostics. (73)

Unlimited Sampling Theorem Based on Fractional Fourier Transform

The recovery of bandlimited signals with high dynamic range is a hot issue in sampling research. The unlimited sampling theory expands the recordable range of traditional analog-to-digital converters (ADCs) arbitrarily, and the signal is folded back into a low dynamic range measurement, avoiding the saturation problem. Since the non-bandlimited signal in the Fourier domain cannot be directly applied to its existing theory, the non-bandlimited signal in the Fourier domain may be bandlimited in the fractional Fourier domain. Therefore, this brief report studies the unlimited sampling problem of high dynamic non-bandlimited signals in the Fourier domain based on the fractional Fourier transform. Firstly, a mathematical signal model for unlimited sampling is proposed. Secondly, based on this mathematical model, the annihilation filtering method is used to estimate the arbitrary folding time. Finally, a novel fractional Fourier domain unlimited sampling theorem is obtained. The theory proves that, based on the folding characteristics of the self-reset ADC, the number of samples is not affected by the modulo threshold, and any folding time can be handled.

Unlimited Sampling From Theory to Practice: Fourier-Prony Recovery and Prototype ADC

Following the Unlimited Sampling strategy to alleviate the omnipresent dynamic range barrier, we study the problem of recovering a bandlimited signal from point-wise modulo samples, aiming to connect theoretical guarantees with hardware implementation considerations. Our starting point is a class of non-idealities that we observe in prototyping an unlimited sampling based analog-to-digital converter. To address these non-idealities, we provide a new Fourier domain recovery algorithm. Our approach is validated both in theory and via extensive experiments on our prototype analog-to-digital converter, providing the first demonstration of unlimited sampling for data arising from real hardware, both for the current and previous approaches. Advantages of our algorithm include that it is agnostic to the modulo threshold and it can handle arbitrary folding times. We expect that the end-to-end realization studied in this paper will pave the path for exploring the unlimited sampling methodology in a number of real world applications.

The Surprising Benefits of Hysteresis in Unlimited Sampling: Theory, Algorithms and Experiments

The Unlimited Sensing Framework (USF) was recently introduced to overcome the sensor saturation bottleneck in conventional digital acquisition systems. At its core, the USF converts a continuous-time high-dynamic-range (HDR) signal into folded, low-dynamic-range, modulo samples and allows the recovery of the HDR signal via algorithmic unfolding. In hardware, however, implementing ideal modulo folding requires careful calibration, analog design and high precision. At the interface of theory and practice, this paper explores a computational sampling strategy that relaxes strict hardware requirements via a novel, mathematically guaranteed reconstruction. We start with a generalized model for USF with two new parameters modeling <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">hysteresis</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">folding transients</i> in addition to the modulo threshold. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hysteresis</i> accounts for mismatches between the reset threshold and the amplitude displacement at the folding time and the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">folding transient</i> is a continuous transition period in the implementation of a reset. Both these effects are motivated by our hardware experiments and also occur in previous, domain-specific applications. We show that hysteresis is beneficial for USF and leverage it to derive the first recovery guarantees in the context of our generalized USF model for a certain sampling rate regime. Additionally, we show how the sampling rate requirement can be greatly reduced via a direct generalization of the proposed recovery. Our theoretical work is corroborated by hardware experiments with a hysteresis enabled, modulo ADC testbed comprising off-the-shelf electronic components. Thus, by capitalizing on a collaboration between hardware and algorithms, our paper enables an end-to-end pipeline for HDR sampling allowing more flexible hardware implementations.

Multi-Dimensional Unlimited Sampling and Robust Reconstruction

Multi-Dimensional Unlimited Sampling and Robust Reconstruction

HIV and Pregnancy: A Retrospective Descriptive Cross-sectional Study of Prevalence, Maternal, Obstetrical, and Neonatal Outcome at a Tertiary Care Hospital in Oman.

ObjectivesWe sought to investigate the prevalence of HIV in pregnant women and the maternal, obstetrical, and neonatal outcomes over 13 years (2005–2017) at Sultan Qaboos University Hospital, a tertiary hospital in Muscat, Oman.MethodsOur study design was a retrospective descriptive cross-sectional study of HIV-positive women in the department of obstetrics and gynecology. We had an unlimited sample size due to the rarity of the disease. We aimed to include all pregnant Omani women who tested positive for HIV in their antenatal screening from 1 January 2005 to 31 December 2017. The patient records were reviewed using the hospital information system service.ResultsThere were a total of 13 688 women with 104 281 pregnancies over the study period. The prevalence of Omani pregnant women with HIV was 0.1% (1:1000) with 0.03% of seropositive pregnancies (3:10 000). Of these seropositive pregnancies, 78.6% were known HIV carriers, while 21.4% were newly diagnosed cases. The live birth rate was 90.3%, with 9.7% resulting in miscarriage. All the miscarriages were to known HIV-positive mothers who were managed in accordance with international guidelines. Of the live births, 10.7% were unknown HIV-positive mothers with a mean gestational age of 39.67 weeks and a mean birth weight of 3.2 kg. The rate of mother-to-child transmission (MTCT) of HIV in this group was 33.3%. In contrast, 89.3% of the live births to known HIV-positive mothers delivered neonates with a mean gestational age of 37.4 weeks and a mean birth weight of 2.6 kg with 0.0% MTCT. Modes of delivery, antepartum, intrapartum and postpartum complications as well as long-term neonatal outcomes were analyzed according to the status of the mother at first presentation.ConclusionsStrategies have been placed by programs in Oman to focus on the wellbeing of pregnant women and the protection of newborns against HIV infection. Strict implementations on preventing MTCT allowed preventing HIV in children possible. Antiretroviral therapy significantly reduces vertical transmission of HIV, in addition to abstinence of breastfeeding. More importantly, all HIV-positive pregnant women should follow the prevention of MTCT programs set out by the Ministry of Health.

Application of Label-Free Proteomics for Quantitative Analysis of Urothelial Carcinoma and Cystitis Tissue.

A label-free approach based on a highly reproducible and stable workflow allows for quantitative proteome analysis . Due to advantages compared to labeling methods, the label-free approach has the potential to measure unlimited samples from clinical specimen monitoring and comparing thousands of proteins. The presented label-free workflow includes a new sample preparation technique depending on automatic annotation and tissue isolation via FTIR-guided laser microdissection, in-solution digestion, LC-MS/MS analyses, data evaluation by means of Proteome Discoverer and Progenesis software, and verification of differential proteins. We successfully applied this workflow in a proteomics study analyzing human cystitis and high-grade urothelial carcinoma tissue regarding the identification of a diagnostic tissue biomarker. The differential analysis of only 1mm2 of isolated tissue cells led to 74 significantly differentially abundant proteins.

FACTORS INFLUENCING THE INTENTION AND DECISION OF CHINESE HIGH SCHOOL STUDENTS TO STUDY AT HIGHER EDUCATION INSTITUTIONS IN MALAYSIA

The internationalization of higher education has provided more opportunities for China students. In view of the problems of studying abroad and cross-border of higher education, a large number of studies have been found in Malaysia. Therefore, the main objective of this study is to find out the main factors that influence the choice of Chinese high school students to study in Malaysia. Theory of planned behaviour (TPB) has been applied in this study considering the theory essentially studied consumer behaviour especially in the field of marketing. The target population of this study is all the third-year high school students, who are in the urban area of four third-tier cities in Jiangxi province of China and the unit of analysis is every third-year high school student, who is in the urban area of four third-tier cities in Jiangxi province of China. In this study, the unlimited probability sampling design or simple random sampling is utilized. It was found in this study that academic expectation is not significant in influencing China’s students’ intention to study in Malaysia and China’s student intention to study in Malaysia does not mediate between academic expectation and decision to study in Malaysian higher education institution. With the vast population of China with different demographic settings due to cultural and background differences, this study may not have conclusively covered all spectrum for this study. However, this can be done by having a larger coverage of China target population, entrepreneur or marketers have to hire a highly qualified academic staffs to convey appropriate and high-quality knowledge to the students. The brand equity of foreign students was one of the significant factors that impact their enrolment in of higher education institution. Notably, this study improves the current written literature on influential factors towards intention of student enrolment in of higher education institution. However, future researchers are advisable to ensure target respondents of questionnaire survey are distributed fairly based on the region and to produce a result with higher generalizability and representative for all foreign students. Article visualizations:

On Unlimited Sampling and Reconstruction

Shannon's sampling theorem is one of the cornerstone topics that is well understood and explored, both mathematically and algorithmically. That said, practical realization of this theorem still suffers from a severe bottleneck due to the fundamental assumption that the samples can span an arbitrary range of amplitudes. In practice, the theorem is realized using so-called analog-to-digital converters (ADCs) which clip or saturate whenever the signal amplitude exceeds the maximum recordable ADC voltage thus leading to a significant information loss. In this paper, we develop an alternative paradigm for sensing and recovery, called the Unlimited Sampling Framework. It is based on the observation that when a signal is mapped to an appropriate bounded interval via a modulo operation before entering the ADC, the saturation problem no longer exists, but one rather encounters a different type of information loss due to the modulo operation. Such an alternative setup can be implemented, for example, via so-called folding or self-reset ADCs, as they have been proposed in various contexts in the circuit design literature. The key task that we need to accomplish in order to cope with this new type of information loss is to recover a bandlimited signal from its modulo samples. In this paper we derive conditions when perfect recovery is possible and complement them with a stable recovery algorithm. The sampling density required to guarantee recovery is independent of the maximum recordable ADC voltage and depends on the signal bandwidth only. Our recovery guarantees extend to measurements affected by bounded noise, which includes the case of round-off quantization. Numerical experiments validate our approach. Applications of the unlimited sampling paradigm can be found in a number of fields such as signal processing, communication and imaging.

Back is the future: returning samples from Mars for analysis on Earth

Abstract Seeking evidence of life in the solar system will be partly the search for organic signatures in rock matrices. The search for organic matter is common to petroleum exploration on Earth and life search missions to Mars. Despite some commonality between investigations into life records on Earth and Mars, there are also significant differences. Favourable organic concentrations in petroleum source rocks are much higher than those needed for life-search targets on Mars. Choosing samples for collection on Mars for return to Earth requires more care at earlier stages than needed for collection of samples on Earth. During and after collection, samples of Mars must be protected from organic contamination that could confuse their potentially weak and poorly understood signals. While operations on Mars provide effectively unlimited samples but with limited instrumentation, analysis on Earth involve constrained amounts of returned samples but access to the world’s best analytical capabilities. Returning samples from Mars also presents the potential for historical firsts including new technologies and important preparations for the eventual human exploration of the Red Planet.

Outstanding Performance of Novel Magnetic Beads for Efficient Purification of His-Tagged Proteins

Placing of affinity tags at desired position of the proteins has been widely used to facilitate protein separation. One of the most commonly method for protein separation is nickel ion (Ni2+) affinity chromatography. Complex steps and time consuming in nickel ion affinity chromatography have caused high demand for alternative purification methods that allow direct and rapid separation of His-tagged proteins. In the present study, magnetic core–shell beads enriched with Ni2+-nitrilotriacetate (Ni-NTA) on their surface were prepared in this study by precipitation polymerization, with a uniform size of about 10 μm. The presented Ni2+ amount was 2.23%, which endowed the spheres with excellent magnetic responsivity and dispersity. We compared the magnetic beads enrichment method and nickel ion affinity chromatography method for extraction of His-tagged protein sample with different concentrations. The results revealed that, when compared with nickel ion affinity chromatography, extraction efficiency, purity of the extracted protein, and regeneration effort were much higher with the magnetic beads enrichment method. By using magnetic beads enrichment method, samples could be separated within 20 s, and purified within 1 h, with unlimited flow velocity and sample capacity. In addition, the magnetic beads enrichment method was particularly promising for the separation of His-tagged proteins in less samples.

Online Preconcentration in Capillaries by Multiple Large-Volume Sample Stacking: An Alternative to Immunoassays for Quantification of Amyloid Beta Peptides Biomarkers in Cerebrospinal Fluid.

A novel electrokinetic preconcentration approach, so-called multiple pressure-assisted large-volume sample stacking with an electroosmotic flow pump (M-PA-LVSEP), was developed to allow in-capillary enrichment and separation of analytes from unlimited sample volumes. With this approach, the inherent limitation of in-capillary electrokinetic preconcentrations to the separation capillary volume can be overcome. The M-PA-LVSEP protocol relies on repeated cycles of pressure-assisted electroosmotic pumping and injection of extremely large sample volumes for analyte stacking and sample matrix removal. This technique was developed to address the challenge of sensitive and simultaneous determination of several amyloid β (Aβ) peptides, which are biomarkers for the molecular diagnosis of Alzheimer's disease (AD). For the first time, reliable quantification of different species of fluorescently derivatized Aβ peptides, that is, Aβ 1-42, Aβ 1-40, and Aβ 1-38 down to subnanomolar ranges in cerebrospinal fluids (CSF) from AD and non-demented patients (healthy controls) was made possible without recourse to immunoassay, immunoprecipitation, or mass spectrometry approaches. Based on the stacking from a sample plug representing up to 400% of the total capillary volume, sensitive enhancement factors up to 170 could be achieved with this "antibody free" approach. Quantification limits for these Aβ peptides down to 0.05 nM with capillary electrophoresis coupled with laser-induced fluorescent detection could be obtained. Excellent agreement between results from M-PA-LVSEP and the gold standard ELISA method was achieved for measurements of Aβ 1-42 in CSF, with a determination correlation (r2) better than 0.993.

ANOMALY INTERACTIONS AND THE CROSS-SECTION OF STOCK RETURNS

This study provides new evidence on anomaly interactions, as well as on the cross-section of returns in all-but-microcap universe of U.S. stocks over the 42-year sample period from 1971 to 2013. The five anomalies being examined are size, value, profitability, investment/asset growth, and momentum. We form 5x5 conditional double-sort portfolios for each pair of anomaly variables, resulting in 20 different 5x5 sorts when using each variable in the first-stage sorting and the remaining four in the second-stage sorting. The interrelation between each pair of anomaly variables is evaluated on the basis of the monotonic relation (MR) test of Patton and Timmermann (2010) for portfolio raw returns, and in addition, by means of the Sharpe ratio comparisons. Moreover, we run Fama-MacBeth (1973) cross-sectional regressions to compare the relative explanatory power of each variable in the presence of the others. The results show that investment/asset growth and momentum dimensions capture the cross-sectional return patterns better than size, value, or profitability. The relative efficacy of momentum is higher in all-but-microcap universe than previously documented for the corresponding unlimited market-cap samples of U.S. stocks.

Utilizing the ultrasensitive Schistosoma up-converting phosphor lateral flow circulating anodic antigen (UCP-LF CAA) assay for sample pooling-strategies

BackgroundMethodological applications of the high sensitivity genus-specific Schistosoma CAA strip test, allowing detection of single worm active infections (ultimate sensitivity), are discussed for efficient utilization in sample pooling strategies. Besides relevant cost reduction, pooling of samples rather than individual testing can provide valuable data for large scale mapping, surveillance, and monitoring.MethodThe laboratory-based CAA strip test utilizes luminescent quantitative up-converting phosphor (UCP) reporter particles and a rapid user-friendly lateral flow (LF) assay format. The test includes a sample preparation step that permits virtually unlimited sample concentration with urine, reaching ultimate sensitivity (single worm detection) at 100% specificity. This facilitates testing large urine pools from many individuals with minimal loss of sensitivity and specificity. The test determines the average CAA level of the individuals in the pool thus indicating overall worm burden and prevalence. When requiring test results at the individual level, smaller pools need to be analysed with the pool-size based on expected prevalence or when unknown, on the average CAA level of a larger group; CAA negative pools do not require individual test results and thus reduce the number of tests.ResultsStraightforward pooling strategies indicate that at sub-population level the CAA strip test is an efficient assay for general mapping, identification of hotspots, determination of stratified infection levels, and accurate monitoring of mass drug administrations (MDA). At the individual level, the number of tests can be reduced i.e. in low endemic settings as the pool size can be increased as opposed to prevalence decrease.ConclusionsAt the sub-population level, average CAA concentrations determined in urine pools can be an appropriate measure indicating worm burden. Pooling strategies allowing this type of large scale testing are feasible with the various CAA strip test formats and do not affect sensitivity and specificity. It allows cost efficient stratified testing and monitoring of worm burden at the sub-population level, ideally for large-scale surveillance generating hard data for performance of MDA programs and strategic planning when moving towards transmission-stop and elimination.

Biomonitoring of environmental stress in Pollicipes pollicipes from the northern coast of Portugal: a non-destructive approach using haemolymph

In the intertidal area, the interactions between anthropogenic contaminants and natural variations (biotic and abiotic factors) are poorly understood. Consequently, there is a great need for new assessment procedures to characterize the biological responses occurring in organisms from this extreme environment. Considering the intrinsic inter-individual variations among organisms from a single population, it is important to propose new methods that address this variability, by validating a sampling strategy in target groups of organisms, encompassing seasonal fluctuations. This strategy must however be less invasive than traditional methods, avoiding the mandatory sacrifice of the sampled organisms. By doing so, it is also possible to increase the ecological relevance of obtainable data, and contribute to minimize damage to endangered species. The main purpose of the present study was to assess the influence of seasonal variations in the responses elicited by anthropogenic compounds on a marine crustacean species, by using a biomarker-based approach. According to this purpose, the seasonal variations in key physiological responses (biomarkers) were investigated in the crustacean Pollicipes pollicipes from the Northern coast of Portugal. Biomarkers used for this purpose were the activity of the phase II biotransformation isoenzymes glutathione-S-transferases (GSTs), the activity of cholinesterases (ChEs), and the levels of lipid peroxidation (TBARS). All biomarkers were quantified in distinct tissues (such as cirri, and peduncle) and haemolymph (a non-destructive source of biological samples). The glycogen content in peduncle tissue, and the variation in haemocyte number in haemolymph were also analyzed. Samples were collected monthly, during a year, in Lavadores, located in the proximity of an estuarine area (Douro River). The results showed a seasonal pattern in all tested biomarkers. The results also showed a significant increase in GSTs activities, and in peroxidative damage, especially during warmer months. The lowest ChEs values were recorded during the rainy season. The results also showed a similar pattern among all tested tissues, validating the proposed use of the haemolymph as a source tissue for non-lethal sampling strategy for biomarker determinations. Glycogen content was apparently related to the reproductive cycle, with lower values being observed in spring and summer. Total haemocyte count (THC) increased during summer months. The results pointed to an influence of natural variations in the levels of biomarkers in P. pollicipes, highly dependent upon abiotic factors, a factor that must be considered when interpreting biological responses elicited by anthropogenic contaminants from the marine coastal environment. The validation of haemolymph as a non-lethal source tissue for the quantification of biomarkers was successfully attained, opening the possibility of less invasive and almost unlimited sampling in a small number of organisms.

Precision of maximum likelihood estimation in adaptive designs.

There has been increasing interest in trials that allow for design adaptations like sample size reassessment or treatment selection at an interim analysis. Ignoring the adaptive and multiplicity issues in such designs leads to an inflation of the type 1 error rate, and treatment effect estimates based on the maximum likelihood principle become biased. Whereas the methodological issues concerning hypothesis testing are well understood, it is not clear how to deal with parameter estimation in designs were adaptation rules are not fixed in advanced so that, in practice, the maximum likelihood estimate (MLE) is used. It is therefore important to understand the behavior of the MLE in such designs. The investigation of Bias and mean squared error (MSE) is complicated by the fact that the adaptation rules need not be fully specified in advance and, hence, are usually unknown. To investigate Bias and MSE under such circumstances, we search for the sample size reassessment and selection rules that lead to the maximum Bias or maximum MSE. Generally, this leads to an overestimation of Bias and MSE, which can be reduced by imposing realistic constraints on the rules like, for example, a maximum sample size. We consider designs that start with k treatment groups and a common control and where selection of a single treatment and control is performed at the interim analysis with the possibility to reassess each of the sample sizes. We consider the case of unlimited sample size reassessments as well as several realistically restricted sample size reassessment rules. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

On the accuracy of paleodiversity reconstructions: a case study in Antarctic Neogene radiolarians

The deep-sea Cenozoic planktonic microfossil record has the unique characteristics of continuously well-preserved populations of most species, with virtually unlimited sample size, and therefore constitutes, in principle, a major resource for macroevolutionary research. Antarctic Neogene radiolarians in particular, are diverse, abundant and consistently well-preserved and evolved rapidly. This fauna is, in theory, a near-perfect testing ground for paleodiversity reconstructions. In this study we determined the diversity history of these faunas from a new quantitative, taxonomically complete data set from Neogene and Quaternary sections at several Antarctic sites. The pattern retrieved by our whole-fauna data set shows a significant, largely extinctionless ecological change in faunal composition and decrease in the evenness of species' abundances during the late Miocene, followed 3 Myr later, at around 5 Ma, by a significant drop in diversity. We tentatively associate this ecological event with a synchronous, regional change in the composition of the primary producers, but as yet cannot identify any environmental changes associated with the later extinction. Further, our whole-fauna diversity history was compared to diversity computed from much less complete, biostratigraphically oriented studies of species' occurrences, compiled in the Neptune database and reconstructed by using subsampling methodologies. Comparison of our whole-fauna and subsampling-reconstructed diversity patterns shows that the first-order trends are the same in both, suggesting that, to some degree, such literature compilations can be used to explore diversity history of plankton. However, our results also highlight substantial errors and distortions in the reconstructed diversity which make it poorly suited to more-detailed studies (e.g., for comparison of diversity history with paleoenvironmental history). We conclude that detailed studies of plankton diversity, and particularly those attempting to understand the relation between diversity and paleoceanographic change, should be based on taxonomically comprehensive, quantitative data.

An adaptive sampling method based on optimized sampling design for fishery-independent surveys with comparisons with conventional designs

The adaptive cluster sampling method is widely applied in terrestrial systems; however, it is not suitable for fisheries surveys because of the high cost of unlimited sampling in practice. An adaptive approach is often used in fisheries surveys to allocate sampling effort, usually following a stratified random design. Development of an adaptive sampling method based on optimized sampling design (this design has been suggested by previous study for fishery-independent surveys) has been not yet carried out. An adaptive sampling method based on optimized sampling design using the criterion of minimization of the mean of the shortest distance (MMSD) in the first phase was constructed in this study and compared with five other sampling designs: simple random, stratified random, adaptive based on stratified sampling, systematic, and optimum design based on the MMSD criterion. This design performed neither the best nor the worst among the six sampling designs considered in this study, but its advantages were obvious when the sampling effort saved using this design was considered in the comparison. This method tends to be more flexible and find fish aggregations more precisely. It is based on a more objective sampling design in the first phase compared with other adaptive sampling designs based on stratified sampling designs. We suggest that this design be considered in developing fishery-independent survey programs.