Valuable Function Research Articles

Preoperative assessment with functional studies of the liver

Background: Postoperative liver failure is the major cause of mortality and morbidity after partial liver resection, and develops as a result of insufficient remnant liver function. The aim of study was to sum up our experience on the most clinically relevant and novel liver function tests used for the assessment of hepatic function before liver surgery. Materials and Methods: ICG-test,methacetin breath test and 99mTc-technephyt hepatobiliary scintigraphy (HBS) were performed prior to major resection in 60 high-risk patients with liver tumors, including 15 patients with hepatocellular carcinoma. Liver function determined with HBS was compared with methacetin breath and ICG test by unified scale. Results: Passive liver function tests, including biochemical parameters and clinical grading systems, are not accurate enough in predicting outcome after liver surgery. Dynamic quantitative liver function tests such as the ICG test is more accurate as it measures the elimination process of a substance that is cleared and metabolized almost exclusively by the liver. However, this test only measure global liver function. Nuclear imaging techniques such as 99mTc-HBS can measure both total and future remnant liver function, and potentially identify patients at risk for postresectional liver failure. Meanwhile,13C-methacetin breath test measures the microsomal capacity of the liver. In fact, a strong positive association (r 0.73, p<0.01) was found between 13C-methacetin breath test determined with HBS, a positive moderate uphill relationship between Results of ICG & breath test (r 0.53, p<0.01)and ICG& HBS(r 0.6, p<0.01) Conclusions: As there is not one test that can measure all components of liver function, liver functional reserve remains to be estimated from combination of quantitative liver function tests. Presently, combination of 99mTc-technephyt HBS, ICG and 13C-methacetin breath test seems to be the most valuable liver function estimate, as its can measure multiple aspects of liver function in specifically the future remnant liver.

Two Level Colocation Demand Response with Renewable Energy

Demand response is considered as a valuable functionality of the power grid and its potential impacts continue expanding with grid modernization. Colocation data centers (simply called colocation) are recognized as a notably promising resource for demand response due to their high power demand and remarkable potential in demand management. A major challenge of colocation demand response is the split incentive, that is, colocation operators desire demand response for financial compensation while tenants may not embrace demand response due to lack of incentives. Another key challenge is caused by renewable energy co-located with data centers. Demand response mechanisms overlooking the uncertainty of renewable would cause much inefficiency in terms of energy saving and economic aspects. Existing work considers the two challenges separately in the context of data centers. By contrast, this work jointly addresses them and specially studies mechanism design for colocation data centers in presence of co-located renewable. We propose a hierarchical demand response scheme, which is based on a new two-level market mechanism that results in a win-win situation for both parties, i.e., tenants who choose to reduce power demand obtain financial rewards from the operator, while the operator receives financial compensation from the electric power company due to its tenants' demand reduction. At each demand response period, the colocation operator solicits bids (amount of energy reduction) from tenants and tenants who choose to participate responds to the operator with their bids. The proposed mechanism provably converges to a unique equilibrium solution, and at the equilibrium, neither the operator or tenants can improve their individual economic performance by changing their own strategies. Further, we present a stochastic optimization based algorithm, which uses predictions of the co-located renewable to determine the colocation operator's best strategy. At the equilibrium, the algorithm has a provable economic performance guarantee in terms of the prediction error. We finally evaluate the designed mechanism via detailed simulations and the results show the efficacy and validate the theoretical analysis for the mechanism.

An example of multi-habitat restoration: Conceptual assessment of benefits from merging shellfish-reef and boulder-reef restorations

Multi-habitat restoration should be considered for conservation of habitat-types that are ecologically-related and regularly co-occur. Multi-habitat restoration has been used to a limited extent for marine habitats including oysters, mangroves and seagrass. Recent increases in research and understanding of shellfish-reefs and boulder/cobble-reefs means they should likewise be considered for integrated restoration. Importantly, boulders have recently been used as the foundation for several large-scale oyster-reef restorations. These would benefit from improved recognition that multiple distinct habitat-types are involved each associated with distinct knowledge pools. These habitat-types mostly have similar restoration objectives, they often co-occur pre-disturbance, and they share varied taxa. These linkages mean that opportunities may be missed if restorations are only considered separately in contexts where an integrated approach is feasible; restoration of one habitat may benefit from concurrent restoration of the other and the sum of benefits from integration may outweigh the sum from restorations done separately. Here, I discuss concepts concerning five potential synergies: 1) boulders provide natural hard-substrata that initiates shellfish recruitment, 2) boulders produce beneficial hydrological heterogeneity, increasing recruitment of some shellfish species, 3) shellfish generate self-sustaining supplies of novel hard-substrata habitat used by boulder/cobble species thus expanding the original restoration site footprint, 4) large shellfish populations strengthen valuable ecological functions in boulder habitats, and 5) boulders and shells together increase overall diversity of available hard-substrata types, and thus of associated specialist species. Not only restoration outcomes, but also objectives and planning can be improved by integrating knowledge from both habitat-types to encompass these five synergies.

Mixing Properties of Room Temperature Patch‐Antenna Receivers in a Mid‐Infrared (λ ≈ 9 µm) Heterodyne System

AbstractA room‐temperature mid‐infrared (λ = 9 µm) heterodyne system based on high‐performance unipolar optoelectronic devices is presented. The local oscillator (LO) is a quantum cascade laser (QCL), while the receiver is an antenna coupled quantum well infrared photodetector optimized to operate in a microcavity configuration. Measurements of the saturation intensity show that these receivers have a linear response up to very high optical power, an essential feature for heterodyne detection. By providing an accurate passive stabilization of the LO, the heterodyne system reaches at room temperature the record value of noise equivalent power (NEP) of 30 pW at 9 µm and in the GHz frequency range. Finally, it is demonstrated that the injection of microwave signal into the receivers shifts the heterodyne beating over the large bandwidth of the devices. This mixing property is a unique valuable function of these devices for signal treatment in compact QCL‐based systems.

Understanding asset holdings of Vietnamese households

This paper examines household management in terms of saving and spending of financial and real (primarily gold and jewelry) asset holdings among Vietnamese households and the extent to which these are used when a major health shock or a family event-expenditure shock occurs. Using 2002–06 Vietnam Household Living Standard Surveys (VHLSS) pooled data, this study demonstrates that the range of assets households rely upon for precautionary saving is broader than those described in standard household saving portfolio literature. We find the enduring presence of non-conventional assets such as gold and other precious metals in many households, although this significantly declined during the reference period. We also found significant negative correlation between education level and household’s decision to own gold. On the other hand, the positive and significant correlation between the sale of gold and the incidence of having a hospitalized family member or a funeral suggests that Vietnamese households tend to rely on these assets as precautionary saving. This illustrates their valuable function beyond the more commonly known cultural purpose i.e. inheritance bequests, dowries and offerings. The study provides important insights for savings mobilization such as financial literacy education and reducing expenditure shocks by improving health insurance system.

Ortho/Ipso Alkylborylation of Aryl Iodides.

This work describes a method for the difunctionalization of aryl iodides to generate polysubstituted arenes via Pd catalysis. The reaction hinges on the unique interplay between norbornene and the metal catalyst to impart a guided ortho C-H alkylation event followed by a programmatic ipso borylation to provide a diverse array of substituted arene products. The utility of this transformation is demonstrated through the functionalization of the boronic ester to a variety of valuable functionalities.

Tuning Isonitrile/Tetrazine Chemistry for Accelerated Deprotection and Formation of Stable Conjugates.

The isocyano group is a valuable functionality for bioorthogonal reactions because it rapidly reacts with tetrazines to either form stable conjugates or release payloads from 3-isocyanopropyl groups. Here we provide mechanistic insights into the dissociative steps that follow the initial cycloaddition and analyze how structural modifications affect these processes. Three main outcomes of this study have important implications for designing such groups for bioorthogonal applications. First, anion-stabilizing substituents at C-2 of the 3-isocyanopropyl group promote β-elimination and accelerate deprotection. Second, tetrazines with bulky substituents form stable imine conjugates even with primary isonitriles that are otherwise rapidly hydrolyzed. Third, the elimination step is independent from hydrolysis to the aldehyde and instead can occur directly from the imine intermediate. These findings will allow tuning the structures of tetrazine and isonitrile reactants for application in bioorthogonal ligation and release chemistry.

Predictions of kelp distribution shifts along the northern coast of Japan

AbstractJapanese kelps are important because they perform a valuable ecosystem function of coastal kelp forest formation, and they are important food resources. The present study aimed to predict future shifts in major kelp species in northern Japan under different climate change scenarios. From a database of cold temperate kelp species in Japan, we extracted 1,958 data points to estimate the distribution of 11 kelp species that inhabit the waters around northern Japan. Distributions of the past (1980s) and the future (2040s and 2090s) were estimated using a species distribution model (MaxEnt). Variation in summer and winter sea surface temperatures was the factor most responsible for the estimated distribution patterns for most species; the length of natural rocky coasts and wave height were also important for some species. A forecast of shifts in distributions based on different Intergovernmental Panel on Climate Change scenarios showed that kelp species diversity in Japan would significantly decrease. By the 2090s, their habitat range overall was estimated to decline to 30–51% of that of the 1980s with moderate warming (Representative concentration pathways [RCP] 4.5) and to 0–25% with severe warming (RCP 8.5). The model predicted that 6 of 11 cold temperate kelp species may become extinct around Japan by the 2090s (RCP 8.5). Commercially important species, such as Saccharina japonica, are also expected to decline greatly, which may affect kelp fisheries and aquaculture in northern Japan.

Recent Advances in Difluoromethylthiolation

The difluoromethylthio group (HCF2S), which has been identified as a valuable functionality in drug and agrochemical discovery, has received increased attention recently. Two strategies, difluoromethylation and direct difluoromethylthiolation, have been well established for HCF2S incorporation. The former strategy suffers from the need to prepare sulfur-containing substrates. In contrast, direct difluoromethylthiolation is straightforward and step-economic. This short review covers the recent advances in direct difluoromethylthiolation, including electrophilic, radical, and transition-metal-catalyzed or -promoted reactions­.1 Introduction2 Electrophilic Difluoromethylthiolation3 Radical Difluoromethylthiolation4 Transition-Metal-Catalyzed or -Promoted Difluoromethylthiolation5 Conclusions and Perspectives

ECM-enriched alginate hydrogels for bioartificial pancreas: an ideal niche to improve insulin secretion and diabetic glucose profile.

The success of a bioartificial pancreas crucially depends on ameliorating encapsulated beta cells survival and function. By mimicking the cellular in vivo niche, the aim of this study was to develop a novel model for beta cells encapsulation capable of establishing an appropriate microenvironment that supports interactions between cells and extracellular matrix (ECM) components. ECM components (Arg-Gly-Asp, abbreviated as RGD) were chemically incorporated in alginate hydrogels (alginate-RGD). After encapsulation, INS-1E beta cells outcome was analyzed in vitro and after their implantation in an animal model of diabetes. Our alginate-RGD model demonstrated to be a good in vitro niche for supporting beta cells viability, proliferation, and activity, namely by improving the key feature of insulin secretion. RGD peptides promoted cell-matrix interactions, enhanced endogenous ECM components expression, and favored the assembly of individual cells into multicellular spheroids, an essential configuration for proper beta cell functioning. In vivo, our pivotal model for diabetes treatment exhibited an improved glycemic profile of type 2 diabetic rats, where insulin secreted from encapsulated cells was more efficiently used. We were able to successfully introduce a novel valuable function in an old ally in biomedical applications, the alginate. The proposed alginate-RGD model stands out as a promising approach to improve beta cells survival and function, increasing the success of this therapeutic strategy, which might greatly improve the quality of life of an increasing number of diabetic patients worldwide.

Hydrogen Atom Transfer Induced Boron Retaining Coupling of Organoboronic Esters and Organolithium Reagents.

α-Functionalization of alkyl boronic esters and homologation of aryl boronic esters by regioselective radical C(sp3)–H activation in boron-ate complexes is reported. Reaction of commercial or readily accessed aryl boronic acid pinacol esters with alkyl lithium reagents provides boron-ate complexes. Selective α-C–H abstraction by in situ generated trifluoromethyl radicals leads to radical anions that undergo electron transfer oxidation followed by 1,2-aryl/alkyl migration from boron to carbon to give the α-arylated/alkylated alkyl boronic esters. The valuable boronic ester functionality remains in the products and the cheap trifluoromethyl iodide acts as the oxidant in these C–C couplings. The 1,2-alkyl migration from boron to carbon is highly stereospecific allowing access to stereoisomerically pure boronic esters.

How progressive vegetation die‐off in a tidal marsh would affect flow and sedimentation patterns: A field demonstration

AbstractCoastal marshes provide valuable ecosystem functions, but some are facing increasing risks of vegetation loss due to sea level rise and other stressors. A key question is how tidal flow and sedimentation patterns are affected by the spatiotemporal patterns of vegetation loss, as sediment accretion with sea level rise largely affects the potential for marsh recovery. Here, we performed a field study in a macrotidal reed marsh and simulated typical spatiotemporal patterns of vegetation loss by consecutive mowing. For each mowing pattern, the spatial patterns of flow velocities and sedimentation rates were recorded. Our results indicate that initial vegetation loss in inner marsh portions, with an intact vegetation belt alongside channel edges, has limited effect on tidal flows over the marsh. However, subsequent creation of unvegetated corridors connecting the bare inner marsh and the channels increases flow velocities in these corridors but not in remaining vegetation patches. Finally, when all vegetation is removed, sheet flow occurs over the whole marsh instead of concentrated channel flow. Effects on spatial sedimentation patterns are complex and not significant on all measuring locations. Nevertheless, our study indicates that complete vegetation removal results in redistributed sedimentation patterns, with a general tendency of locally reduced sedimentation rates close (&lt; 15 m) to channels and increased sediment supply to inner marshes 15–50 m from channels. Our results highlight that feedbacks between spatial patterns of vegetation loss, tidal sediment transport, and deposition are key to understanding and mitigating risks of marsh loss in face of sea level rise.

Hypervisor-Based Protection of Code

The code of a compiled program is susceptible to reverse-engineering attacks on the algorithms and the business logic that are contained within the code. The main existing countermeasure to reverse-engineering is obfuscation. Generally, obfuscation methods suffer from two main deficiencies: 1) the obfuscated code is less efficient than the original and 2) with sufficient effort, the original code may be reconstructed. We propose a method that is based on cryptography and virtualization. The most valuable functions are encrypted and remain inaccessible even during their execution, thus preventing their reconstruction. A specially crafted hypervisor is responsible for decryption, execution, and protection of the encrypted functions. We claim that the system can provide protection even if the attacker: 1) has access to the operating system kernel and 2) can intercept communication over the system bus. The evaluation of the system's efficiency suggests that it can compete with and outperform obfuscation-based methods.

Complexity Leadership Theory: A Perspective for State-Owned Enterprises in Ghana

This article explores the bureaucratic leadership which has bedeviled state owned enterprises for many decades and how its efficacy can be in the 21st century business environment where there uncertainty and chaos. In some manufacturing and state owned enterprises, these theories of traditional bureaucratic leadership approach and decision making strategies persist even though technology and innovation supposed to have taken the greater part of the way of thinking and making organizational objectives achieved through modern way of managing business entities. Thus, SOEs are critical to the economic activity in emerging market countries. The creation of SOEs was meant to provide employment, meet social and political needs, and operate in the sectors of the economy that were of strategic importance to the state. The problem is to offer alternatives of bureaucratic structure that has been used in SOEs and how best to use these alternative theories in practical terms. The pace of change confronting organisations today has added complexity to the organisational landscape and now calls for more flexible and adaptive leadership. Adaptive leaders are able to work more effectively in the unstable global business environment and are also able to adopt a proactive approach in order to keep abreast of the increasing stakeholder pressures in the enterprises. However, inadequate applicability of traditional leadership models have indicated the need to develop new leadership models to solve complex organisational challenge. Hence complexity leadership approach seeks to combine these dynamics to the bureaucratic hierarchies in order to explain the way informal organisational dynamics function properly and also to describe how theses valuable adaptive functions can be promoted to better the operations of SOEs in Ghana.

Significant Increase in Nutrient Stocks Following Phragmites australis Invasion of Freshwater Meadow Marsh but Not of Cattail Marsh

Invasive species are a threat to biodiversity and can cause ecological degradation, however, well-established invasive species may serve valuable ecological functions. For example, in the Laurentian Great Lakes, where nutrient pollution is a major issue, highly productive Phragmites australis (European Common Reed) may provide a nutrient retention service. Yet there is a lack of research comparing carbon and macronutrient stocks in P. australis with resident plant communities, such as cattail and meadow marsh. We quantified the effect of P. australis invasion on carbon and macronutrient standing stocks in a freshwater coastal marsh by comparing the above- and belowground biomass, tissue nutrient concentrations, and annual nutrient standing stocks in marsh invaded by P. australis with cattail marsh (dominated by Typha spp.) and meadow marsh (dominated by Calamagrostis canadensis), which are being displaced by P. australis in Lake Erie coastal marsh. We conclude that the effect of P. australis invasion on carbon and macronutrient standing stocks is dependent on the plant community being replaced. The annual standing stock of carbon, nitrogen, phosphorus, and potassium are consistent between cattail marsh and P. australis-invaded marsh, though cattail marsh contains more magnesium (112 % mean increase) and calcium (364 % mean increase). In contrast, when P. australis replaces meadow marsh, the standing stocks of all measured nutrients and carbon increase significantly (103 - 188 % mean increase). Our study highlights that plant invasions may create trade-offs between ecosystem services. In our case, the increase in nutrient standing stocks when P. australis invades meadow marsh should be weighed against the documented reductions in biodiversity and habitat value.

MicroRNA Triggered DNA "Nano Wheel" for Visualizing Intracellular microRNA via Localized DNA Cascade Reaction.

There is intense interest in visualizing intracellular microRNA (miRNA) in situ due to its valuable diagnostic and prognostic function and expressional heterogeneity. The direct monitoring of intracellular miRNA expressional level with a wide concentration range and in ultralow amount remains a key challenge. Herein, we report a responsive DNA "nano wheel" (DNW) by hybridization of modified six DNA hairpin structures to a programmed DNA nanowire for highly efficient and fast miRNA imaging in living cells. We demonstrate that one target miRNA is able to trigger the nearby DNA hairpins sequential hybridization through accelerated localized DNA cascade reaction (LDCR) along the DNA nanowire and open of the self-quenched hairpins to assemble six-arm branched junction "nano wheel" structure lighted with three fluorescence dye. Notably, the recycled miRNA target further acts as an catalyst to generate multiple lighted "nano wheel" structures, thus one target miRNA enable to trigger strong and amplified fluorescence signal for intracellular sensitive imaging. Meanwhile, the LDCR endows the system with fast reaction kinetics owing to the high local concentration. It outperforms the "one-to-one" conventional molecular beacon (MB) and intermolecular hybridization-based six-arm branched junction in sensitivity and reaction kinetics for intracellular miRNA imaging verified using MCF-7, A549, Hela, and NHDF cells. The programmed DNW provides a useful and valuable tool for rapid and highly efficient visualization of low-abundance miRNA in living cells, which is beneficial to understand the miRNA function and exploration of its biomedical application.

Between Public and Private, Britain and Canada: Newfoundland Radio 1934-1949

This article examines Newfoundland radio during the period when Newfoundland was governed by a British-appointed Commission of Government (1934–1949), devoting particular attention to the political sensitivities and implications involved when one nation essentially assumed control of radio broadcasting in one of its dominions. The BBC had played the role of midwife in bringing the Broadcasting Corporation of Newfoundland into being during the 1930s, and provided regular advice to the Commission of Government, at a time when the countries of the empire were encouraged to follow the Corporation’s public service organisation as a model. The relationship between the BBC and the BCN did come to sour, however, due to a feeling in St. John’s that the larger Corporation was neglecting its tiny counterpart. As will be demonstrated using archival sources, there was some justification for this. Due to the particular constitutional status of Newfoundland, as in effect a Dependency of the United Kingdom, the BBC did not treat it on a par with the self-governing Dominions, which meant that possibilities for exchange were limited or non-existent. As well as examining these political issues, the article will develop a portrait of the unique aspects of Newfoundland’s early radio culture. Newfoundland is a particularly appropriate case study for radio beyond boundaries as, due to its geographical location, listeners have traditionally been exposed to US and Canadian radio stations as well as domestic broadcasters and short-wave frequencies. Furthermore, conventional boundaries between public and private models of broadcasting do not apply in Newfoundland, where commercial radio programming has often performed a valuable public service function.

Frizzled-10 Extracellular Vesicles Plasma Concentration Is Associated with Tumoral Progression in Patients with Colorectal and Gastric Cancer.

Extracellular vesicles (EVs) are involved in intercellular communication during the carcinogenesis. Our attention has been focused on small EVs (sEVs) protein content in colorectal and gastric cancer (CRC and GC). Frizzled (FZD) proteins, a family of receptors comprised in the Wnt signaling pathway, play an important role in the carcinogenesis of CRC and GC. Here, the expression of a specific FZD protein, namely, FZD-10, was investigated in the sEVs extracted from plasma of patients affected by CRC and GC as involved in canonical and noncanonical Wnt signaling in cancer stem cells with a subsequent modification of cellular heterogeneity, omics reprogramming, and tumor plasticity. The expression of FZD-10 protein in the sEVs extracted from plasma of patients affected by CRC and GC and sEVs from plasma of healthy subjects was evaluated against the level of protein Hsp70, established as EVs specific markers along with CD63 and ALIX proteins. The FZD-10 extract from sEVs isolated from plasma of the controls and the CRC or GC subjects indicated that its expression in oncological patients was higher than in the control group, while, at the end of the treatment, it reached values comparable with the average level of controls. Furthermore, the level of FZD-10 in the whole plasma was found comparable with its level in the sEVs extract. The level of FZD-10 in the sEVs represents a potential reliable biomarker with a valuable prognostic function for the diagnosis of CRC and GC and for monitoring the treatment response.

Природа соціального інтелекту особистості та його базові функції

In the article it was shown that social intelligence in psychology is considered as the ability of a person to understand correctly his / her own behavior and the behavior of other people in the society. This ability is very necessary for a person to have an effctive interpersonal interaction and successful social adaptation. Social intelligence implements the functioning of cognitive processes associated with the reflection of a person as a partner in the processes of communication and activities. The main function of social intelligence is to predict the behavior of others. It is emphasized that each type of intelligence contains certain abilities of the personality to perform a certain type of the activities. In this case, for example, «linguistic intelligence» is referred to as «intelligence» by the authors, because it is a complex of integral education, which includes separate abilities to perform a certain type of the activity, and if we talk about a specialist in this sphere of the activity, his / her competences, we remind about the structure of the professional competence of the person. Thus, guided by the narrow sense of understanding the word «intelligence», we distinguish: social intelligence; technical intelligence; artistic intelligence; information intelligence. Thus, the functions of social intelligence of the person are the understanding of other people, adaptation to the requirements of the society, knowledge of the behavior of social subjects, cognitive and behavioral functions, functions of understanding the actions of other people and their influence on them, understanding themselves and modeling behavior in accordance with their needs, goals and abilities, the ability to express spontaneous judgments about other people, to predict the behavior of other people, the functions of adapting to life situations, solving practical problems and situations of everyday life, function of social adaptation, functions to solve problems at the subject-subjective level, self-organization of intelligence, socialization in the society, internalization of social norms and rules, the choice of corresponding reaction in interpersonal interaction, as well as the function of «ensuring adaptability in conditions that constantly predict the formation of a program of successful interpersonal interaction», «planning and forecasting of interpersonal events of the social environment», «motivational function», «the function of social competence», «self-development», «self-cognition» and «self-studying». All these functions can be combined with such generalized functions as cognitive-evaluative, communicative-value, and reflexive correction. At various stages of the performance of the leading function is one of the functions of social intelligence. In particular, the cognitive-evaluative function prevails at the initial stage, while the other two functions create positive conditions for the implementation of the 0xFB01rst one. Achieving the goals of cognitive activity to a large extent provide a communicative and valuable function. The reflexive correction function is essentially aimed at actualizing the strengths and qualities compensating for weak and ine0exFB00ctive features and actions. Such functions of social intelligence of the person are manifested in their subordination and interconnection.

Status of giant clam resources around Okinawa‐jima Island, Ryukyu Archipelago, Japan

Abstract Giant clams provide and support valuable functions to coral reefs, as well as represent a sustainable resource for traditional fisheries throughout the Indo‐Pacific region. The Ryukyu Archipelago (southern Japan) is known to be the northern latitudinal limits of giant clam distribution, but there is only limited information in the literature regarding species diversity, status, and distribution in this region. In this study, we report findings from a rapid survey in 2016, the first of its kind for the Ryukyu Islands, to determine species distribution and abundance of giant clams (tridacnines) around Okinawa‐jima Island. Results indicate the presence of four species with an overall density of 5.03 per 100 m2, from most to least abundant: Tridacna crocea, Tridacna maxima, Tridacna squamosa, and Tridacna noae. The previously reported species Tridacna gigas and Hippopus hippopus were both absent from the surveys. The densities and distributions of tridacnines varied among species and sites, which are likely attributable to efforts in replenishing and protecting stocks of selected species. The most abundant species, T. crocea, is an important fishery species in Okinawa, and has been widely cultured and restocked to augment depleted populations. In comparison, restocking efforts for less popular species, such as T. squamosa, have been limited, and their current sizes and numbers suggest recruitment constraints. Given the importance of the giant clam fishery in this region and the current declines of various species (except T. crocea), further regulations should focus on the protection of larger and mature clams that function as broodstock necessary to maintain spawning and natural recruitment.