line

Case Study: Improving Video (opens in new tab)

Engineers at LINE identified a recurring monthly degradation in video call quality, specifically in Japan, where packet loss increased and frames per second (FPS) dropped toward the end of each month. Investigation revealed that this pattern was caused by mobile ISP bitrate throttling once users exhausted their monthly data caps, which the existing congestion control mechanisms were failing to handle efficiently. To resolve this, the team improved their proprietary CCFS (Congestion Control based on Forward path Status) algorithm to more accurately detect these specific network constraints and maintain stable playback. ### Analysis of Monthly Quality Degradation * Data analysis showed a "monthly cycle" where video decoding FPS was highest at the start of the month and progressively declined toward the end. * This quality drop was specifically tied to an increase in video packet loss, which prevents normal decoding and results in stuttering or frozen frames. * Statistical segmentation revealed the issue occurred almost exclusively on 4G mobile networks rather than Wi-Fi, and was more pronounced in high-bitrate video calls than in voice calls. * The root cause was identified as mobile data plan policies; as users hit their monthly data limits, ISPs impose speed restrictions that create network congestion if the application continues to send high-bitrate data. ### Limitations of Standard Congestion Control * While the IETF RMCAT working group has standardized algorithms like NADA (RFC8698) and SCReAM (RFC8298), real-time two-way communication requires more sensitive response times than one-way streaming. * In two-way calls, even a one-second delay makes natural conversation difficult, meaning the system cannot rely on large buffers to smooth out network instability. * Existing mechanisms were not reacting fast enough to the rigid throughput limits imposed by carrier throttling, leading to packet accumulation in network queues and subsequent loss. ### The CCFS Proprietary Algorithm * LINE utilizes a custom-developed, sender-based algorithm called CCFS (Congestion Control based on Forward path Status). * Unlike older algorithms that rely on Round Trip Time (RTT), CCFS focuses on the "forward path"—the actual path packets take to the receiver—by analyzing feedback on packet arrival times and loss. * CCFS categorizes network status into four distinct states: Default, Probing, Throttled, and Competing. * The system monitors "delay variation"; when it detects a continuous increase in delay exceeding a specific threshold, it transitions to the "Throttled" state to proactively reduce bitrate before the queue overflows. ### Strategies for Quality Improvement * The team focused on refining how CCFS handles the transition into the Throttled state to better align with the artificial bandwidth ceilings created by ISPs. * By improving the sensitivity of forward path status monitoring, the application can more rapidly adjust its transmission rate to stay within the user's current data plan limits. * This technical adaptation ensures that even when a user's mobile speed is restricted, the video remains smooth, albeit at a lower resolution, rather than breaking up due to packet loss. To provide a high-quality communication experience, developers must account for external factors like regional ISP policies. Refining proprietary congestion control algorithms to detect specific patterns, such as monthly data-cap throttling, allows for a more resilient service that maintains stability across diverse mobile environments.

google

Beyond billion-parameter burdens: Unlocking data synthesis with a conditional generator (opens in new tab)

The CTCL (Data Synthesis with ConTrollability and CLustering) framework provides a lightweight alternative to the computationally expensive process of fine-tuning billion-parameter models for differentially private synthetic data generation. By utilizing a 140-million parameter generator and a universal topic model, the system achieves high-quality distribution matching while remaining accessible for resource-constrained applications. This approach allows for the generation of unlimited synthetic samples without incurring additional privacy costs, consistently outperforming existing API-based and large-scale baselines under strict privacy guarantees. ### Pre-training Universal Components The framework relies on two core components developed using large-scale public corpora, which can be reused across different private domains: * **CTCL-Topic:** A universal topic model derived from Wikipedia documents. It uses BERTopic to embed and cluster data into approximately 1,000 distinct topics, each represented by 10 descriptive keywords. * **CTCL-Generator:** A conditional language model based on the 140M-parameter BART-base architecture. It was pre-trained on 430 million description–document pairs from the SlimPajama dataset, with descriptions generated by Gemma-2-2B to ensure the model can generate text based on specific input conditions. ### Learning the Private Domain Once the universal components are established, the framework learns the specific characteristics of a private dataset through a two-step process: * **Differentially Private (DP) Histograms:** The system captures high-level distributional information by creating a DP-protected histogram that represents the percentage of each topic present in the private corpus. * **DP Fine-Tuning:** Each document in the private dataset is associated with its corresponding keywords from the CTCL-Topic model. The CTCL-Generator is then fine-tuned on these keyword-document pairs using differential privacy to ensure individual data points are protected. ### Controllable Data Generation The final stage involves producing the synthetic dataset by sampling from the fine-tuned generator: * **Proportional Sampling:** The system generates data by targeting the exact topic proportions found in the private domain histogram. * **Keyword Conditioning:** For each topic, the model uses the associated 10 keywords as input to prompt the DP fine-tuned generator to produce relevant documents. * **Post-Processing Efficiency:** Because the generator is already fine-tuned with DP, the framework can generate an unlimited number of synthetic samples without further privacy budget expenditure, a significant advantage over iterative selection algorithms. CTCL offers a highly scalable and efficient solution for organizations needing to synthesize private text data without the infrastructure requirements of massive LLMs. Its ability to maintain topic-wise distribution through keyword conditioning makes it an ideal choice for specialized domains where maintaining the statistical utility of the data is as critical as protecting user privacy.

line

The Current State of LY Corporation (opens in new tab)

Tech-Verse 2025 showcased LY Corporation’s strategic shift toward an AI-integrated ecosystem following the merger of LINE and Yahoo Japan. The event focused on the practical hurdles of deploying generative AI, concluding that the transition from experimental models to production-ready services requires sophisticated evaluation frameworks and deep contextual integration into developer workflows. ## AI-Driven Engineering with Ark Developer LY Corporation’s internal "Ark Developer" solution demonstrates how AI can be embedded directly into the software development life cycle. * The system utilizes a Retrieval-Augmented Generation (RAG) based code assistant to handle tasks such as code completion, security reviews, and automated test generation. * Rather than treating codebases as simple text documents, the tool performs graph analysis on directory structures to maintain structural context during code synthesis. * Real-world application includes a seamless integration with GitHub for automated Pull Request (PR) creation, with internal users reporting higher satisfaction compared to off-the-shelf tools like GitHub Copilot. ## Quantifying Quality in Generative AI A significant portion of the technical discussion centered on moving away from subjective "vibes-based" assessments toward rigorous, multi-faceted evaluation of AI outputs. * To measure the quality of generated images, developers utilized traditional metrics like Fréchet Inception Distance (FID) and Inception Score (IS) alongside LAION’s Aesthetic Score. * Advanced evaluation techniques were introduced, including CLIP-IQA, Q-Align, and Visual Question Answering (VQA) based on video-language models to analyze image accuracy. * Technical challenges in image translation and inpainting were highlighted, specifically the difficulty of restoring layout and text structures naturally after optical character recognition (OCR) and translation. ## Global Technical Exchange and Implementation The conference served as a collaborative hub for engineers across Japan, Taiwan, and Korea to discuss the implementation of emerging standards like the Model Context Protocol (MCP). * Sessions emphasized the "how-to" of overcoming deployment hurdles rather than just following technical trends. * Poster sessions (Product Street) and interactive Q&A segments allowed developers to share localized insights on LLM agent performance and agentic workflows. * The recurring theme across diverse teams was that the "evaluation and verification" stage is now the primary driver of quality in generative AI services. For organizations looking to scale AI, the key recommendation is to move beyond simple implementation and invest in "evaluation-driven development." By building internal tools that leverage graph-based context and quantitative metrics like Aesthetic Scores and VQA, teams can ensure that generative outputs meet professional service standards.

google

Enabling physician-centered oversight for AMIE (opens in new tab)

Guardrailed-AMIE (g-AMIE) is a diagnostic AI framework designed to perform patient history-taking while strictly adhering to safety guardrails that prevent it from providing direct medical advice. By decoupling data collection from clinical decision-making, the system enables an asynchronous oversight model where primary care physicians (PCPs) review and finalize AI-generated medical summaries. In virtual clinical trials, g-AMIE’s diagnostic outputs and patient communications were preferred by overseeing physicians and patient actors over human-led control groups. ## Multi-Agent Architecture and Guardrails * The system utilizes a multi-agent setup powered by Gemini 2.0 Flash, consisting of a dialogue agent, a guardrail agent, and a SOAP note agent. * The dialogue agent conducts history-taking in three distinct phases: general information gathering, targeted validation of a differential diagnosis, and a conclusion phase for patient questions. * A dedicated guardrail agent monitors and rephrases responses in real-time to ensure the AI abstains from sharing individualized diagnoses or treatment plans directly with the patient. * The SOAP note agent employs sequential multi-step generation to separate summarization tasks (Subjective and Objective) from more complex inferential tasks (Assessment and Plan). ## The Clinician Cockpit and Asynchronous Oversight * To facilitate human review, researchers developed the "clinician cockpit," a web interface co-designed with outpatient physicians through semi-structured interviews. * The interface is structured around the standard SOAP note format, presenting the patient’s perspective, measurable data, differential diagnosis, and proposed management strategy. * This framework allows overseeing PCPs to review cases asynchronously, editing the AI’s proposed differential diagnoses and management plans before sharing a final message with the patient. * The separation of history-taking from decision-making ensures that licensed medical professionals retain ultimate accountability for patient care. ## Performance Evaluation via Virtual OSCE * The system was evaluated in a randomized, blinded virtual Objective Structured Clinical Examination (OSCE) involving 60 case scenarios. * g-AMIE’s performance was compared against primary care physicians, nurse practitioners, and physician assistants who were required to operate under the same restrictive guardrails. * Overseeing PCPs and independent physician raters preferred g-AMIE’s diagnostic accuracy and management plans over those of the human control groups. * Patient actors reported a preference for the messages generated by g-AMIE compared to those drafted by human clinicians in the study. While g-AMIE demonstrates high potential for human-AI collaboration in diagnostics, the researchers emphasize that results should be interpreted with caution. The workflow was specifically optimized for AI characteristics, and human clinicians may require specialized training to perform effectively within such highly regulated guardrail frameworks.

line

Sharing the workflow of a 3rd (opens in new tab)

This blog post outlines a structured nine-step workflow designed to enhance development efficiency and improve the code review experience within a collaborative team environment. By emphasizing pre-implementation simulation, task visualization through Jira, and proactive self-feedback, the author demonstrates how breaking work into manageable, reviewer-friendly units leads to more predictable and reliable software delivery. The core conclusion is that prioritizing "reviewability" through small, logical increments fosters team trust and reduces technical debt. ### Strategic Planning and Simulation * Begin by thoroughly reviewing requirements and simulating the feature’s behavior, focusing specifically on data flow, state management, and edge cases. * Proactively communicate with stakeholders to clarify ambiguities and suggest user experience improvements before any code is written. * Draft high-level diagrams or flowcharts to map out how data points interact and where specific logic should reside, ensuring a solid architectural foundation. ### Task Visualization and Collaborative Alignment * Organize features into Jira Epics and decompose them into granular tickets that include estimated effort and dependencies. * Sync with teammates early—specifically between workflow design and ticket creation—to align on technical direction and prevent significant rework during the final review stage. * Ensure ticket titles are concise and descriptive to allow teammates to understand the project's progress at a glance. ### PoC-Driven Iteration and Self-Feedback * Conduct Proof of Concept (PoC) or prototyping to validate assumptions and identify unforeseen technical challenges before committing to a final implementation. * Perform self-feedback by checking the volume of code changes; the author suggests a 400-line threshold, beyond which a ticket should be split into sub-tasks to maintain clarity. * Use tools like `git diff` or temporary PR branches to review your own work from the perspective of a reviewer, identifying parts of the code that may be difficult to digest. ### Implementation and Documentation for Reviewers * Commit code in small, meaningful increments with clear messages, following a logical sequence such as defining interfaces before their actual implementations. * Draft Pull Requests (PRs) using standardized templates that include the purpose of the change, affected features, and developer test results. * Include visual aids, such as videos or screenshots, for complex UI changes or intricate workflows to reduce the cognitive load on the reviewer. ### Future Process Refinement * Improve the accuracy of project timelines by strictly recording actual time spent on tickets compared to original estimates in Jira. * Analyze the delta between "Estimated" and "Actual" time to better understand personal development velocity and refine future scheduling. Adopting this systematic approach helps developers transition from simply "writing code" to managing a complete technical lifecycle. For teams prioritizing code quality, implementing a line-count threshold for PRs and scheduling early-stage technical alignment sessions can significantly reduce "review fatigue" and streamline the path to production.

line

Hey, won't you become a (opens in new tab)

Hack Day 2025 serves as a cornerstone of LY Corporation’s engineering culture, bringing together diverse global teams to innovate beyond their daily operational scopes. By fostering a high-intensity environment focused on creative freedom, the event facilitates technical growth and strengthens interpersonal bonds across international branches. This 19th edition demonstrated how rapid prototyping and cross-functional collaboration can transform abstract ideas into functional AI-driven prototypes within a strict 24-hour window. ### Structure and Participation Dynamics * The hackathon follows a "9 to 9" format, providing exactly 24 hours of development time followed by a day for presentations and awards. * Participation is inclusive of all roles, including developers, designers, planners, and HR staff, allowing for holistic product development. * Teams can be "General Teams" from the same legal entity or "Global Mixed Teams" comprising members from different regions like Korea, Japan, Taiwan, and Vietnam. * The Developer Relations (DevRel) team facilitates team building for remote employees using digital collaboration tools like Zoom and Miro. ### AI-Powered Personality Analysis Project * The author's team developed a "Scouter" program inspired by Dragon Ball, designed to measure professional "combat power" based on communication history. * The system utilizes Slack bots and AI models to analyze message logs and map them to the Big 5 Personality traits (Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism). * Professional metrics are visualized as game-like character statistics to make personality insights engaging and less intimidating. * While the original plan involved using AI to generate and print physical character cards, hardware failures with photo printers forced a technical pivot to digital file downloads. ### High-Pressure Presentation and Networking * Every team is allotted a strict 90-second window to pitch their product and demonstrate a live demo. * The "90-second rule" includes a mandatory microphone cutoff to maintain momentum and keep the large-scale event engaging for all attendees. * Dedicated booth sessions follow the presentations, allowing participants to provide hands-on experiences to colleagues and judges. * The event emphasizes "Perfect the Details," a core company value, by encouraging teams to utilize all available resources—from whiteboards to AI image generators—within the time limit. ### Environmental Support and Culture * The event occupies an entire office floor, providing a high-density yet comfortable environment designed to minimize distractions during the "Hack Time." * Cultural exchange is encouraged through "humanity snacks," where participants from different global offices share local treats in dedicated rest areas. * Strategic scheduling, such as "Travel Days" for international participants, ensures that teams can focus entirely on technical execution once the event begins. Participating in internal hackathons provides a vital platform for testing new technologies—like LLMs and personality modeling—that may not fit into immediate product roadmaps. For organizations with hybrid work models, these intensive in-person events are highly recommended to bridge the communication gap and build lasting trust between global teammates.

line

Flexible Multi-site Architecture Designed with N (opens in new tab)

LINE NEXT optimized its web server infrastructure by transitioning from fragmented, manual Nginx setups to a centralized native Nginx multi-site architecture. By integrating global configurations and automating the deployment pipeline with Ansible, the team successfully reduced service launch lead times by over 80% while regaining the ability to use advanced features like GeoIP and real client IP tracking. This evolution ensures that the infrastructure can scale to support over 100 subdomains across diverse global services with high reliability and minimal manual overhead. ## Evolution of Nginx Infrastructure * **PMC-based Structure**: The initial phase relied on a Project Management Console using `rsync` via SSH; this created security risks and led to fragmented, siloed configurations that were difficult to maintain. * **Ingress Nginx Structure**: To improve speed, the team moved to Kubernetes-based Ingress using Helm charts, which automated domain and certificate settings but limited the use of native Nginx modules and complicated the retrieval of real client IP addresses. * **Native Nginx Multi-site Structure**: The current hybrid approach utilizes native Nginx managed by Ansible, combining the speed of configuration-driven setups with the flexibility to use advanced modules like GeoIP and Loki for log collection. ## Configuration Integration and Multi-site Management * **Master Configuration Extraction**: Common directives such as `timeouts`, `keep-alive` settings, and `log formats` were extracted into a master Nginx configuration file to eliminate redundancy across services. * **Hierarchical Directory Structure**: Inspired by Apache, the team adopted a `sites-available` structure where individual `server` blocks for different services (alpha, beta, production) are managed in separate files. * **Operational Efficiency**: This integrated structure allows a single Nginx instance to serve multiple sites simultaneously, significantly reducing the time required to add and deploy new service domains. ## Automated Deployment with Ansible * **Standardized Workflow**: The team replaced manual processes with Ansible playbooks that handle everything from cloning the latest configuration from Git to extracting environment-specific files. * **Safety and Validation**: The automated pipeline includes mandatory Nginx syntax verification (`nginx -t`) and process status checks to ensure stability before a deployment is finalized. * **Rolling Deployments**: To minimize service impact, updates are pushed sequentially across servers; the process automatically halts if an error is detected at any stage of the rollout. To effectively manage a rapidly expanding portfolio of global services, infrastructure teams should move toward a "configuration-as-code" model that separates common master settings from service-specific logic. Leveraging automation tools like Ansible alongside a native Nginx multi-site structure provides the necessary balance between rapid deployment and the granular control required for complex logging and security requirements.

google

Achieving 10,000x training data reduction with high-fidelity labels (opens in new tab)

Google Ads researchers have developed a scalable active learning curation process that reduces the volume of training data required for fine-tuning LLMs by up to four orders of magnitude. By iteratively identifying the most informative and diverse examples through clustering and expert review, the method achieves significantly higher human-model alignment than traditional large-scale crowdsourced datasets. This approach effectively addresses the high costs and complexities of classifying ambiguous content, such as unsafe ads, where high-fidelity data is scarce and concept drift is frequent. ### The Iterative Curation Process * **Initial Labeling:** The process begins with a zero- or few-shot model (LLM-0) that generates a large, typically imbalanced dataset of "positive" and "benign" labels. * **Clustering and Confusion Identification:** Separate clusters are created for each label set; overlapping clusters indicate areas where the model is confused. * **Expert Sampling:** Human experts review pairs of examples located near the decision boundary of these overlapping clusters, prioritizing those that cover a larger area of the search space to ensure diversity. * **Recursive Refinement:** Expert labels are split into fine-tuning and evaluation sets; the model is retrained and the process repeats until model-human alignment plateaus or matches internal expert agreement. ### Measuring Alignment via Cohen’s Kappa * **Metric Selection:** Because ad safety is often subjective, the researchers use Cohen’s Kappa instead of precision and recall to measure how well two independent annotators align beyond chance. * **Performance Benchmarks:** A Kappa value above 0.8 is considered exceptional, while 0.4 is the minimum for acceptability. * **Goal Alignment:** The curation process aims to move model performance toward the "ceiling" of internal human agreement (which measured between 0.78 and 0.81 in these experiments). ### Experimental Results and Efficiency * **Model Scaling:** Experiments involved fine-tuning Gemini Nano-1 (1.8B parameters) and Nano-2 (3.25B parameters) on tasks of varying complexity. * **Drastic Data Reduction:** The curated method reached performance plateaus using fewer than 500 expert-labeled examples, compared to a baseline of 100,000 crowdsourced labels. * **Quality Gains:** Despite using 10,000x less data, the curated models saw up to a 65% improvement in alignment with human experts over the crowdsourced baselines. * **Class Balancing:** The process naturally corrected for production imbalances, moving from <1% positive examples in raw traffic to ~40% in the final curated sets. This curation method is a highly effective strategy for organizations managing high-stakes classification tasks where "ground truth" is subjective or data curation is prohibitively expensive. By shifting focus from data quantity to the quality and diversity of examples at the decision boundary, developers can maintain high-performing models that adapt quickly to evolving safety policies.

google

Insulin resistance prediction from wearables and routine blood biomarkers (opens in new tab)

Researchers at Google have developed a novel machine learning approach to predict insulin resistance (IR) by integrating wearable device data with routine blood biomarkers. This method aims to provide a scalable, less invasive alternative to traditional "gold standard" tests like the euglycemic insulin clamp or specialized HOMA-IR assessments. The study demonstrates that combining digital biomarkers with common laboratory results can effectively identify individuals at risk for type 2 diabetes, particularly within high-risk populations. ## Barriers to Early Diabetes Screening * Insulin resistance is a primary precursor to approximately 70% of type 2 diabetes cases, yet it often remains undetected until the disease has progressed. * Current diagnostic standards are frequently omitted from routine check-ups due to high costs, invasiveness, and the requirement for specific insulin blood tests that are not standard practice. * Early detection is vital because insulin resistance is often reversible through lifestyle modifications, making accessible screening tools a high priority for preventative medicine. ## The WEAR-ME Multimodal Dataset * The research utilized the "WEAR-ME" study, which collected data from 1,165 remote participants across the U.S. via the Google Health Studies app. * Digital biomarkers were gathered from Fitbit and Google Pixel Watch devices, tracking metrics such as resting heart rate, step counts, and sleep patterns. * Clinical data was provided through a partnership with Quest Diagnostics, focusing on routine blood biomarkers like fasting glucose and lipid panels, supplemented by participant surveys on diet, fitness, and demographics. ## Predictive Modeling and Performance * Deep neural network models were trained to estimate HOMA-IR scores by analyzing different combinations of the collected data streams. * While models using only wearables and demographics achieved an area under the receiver operating characteristic curve (auROC) of 0.70, adding fasting glucose data boosted the auROC to 0.78. * The most comprehensive models, which combined wearables, demographics, and full routine blood panels, achieved the highest accuracy across the study population. * Performance was notably strong in high-risk sub-groups, specifically individuals with obesity or sedentary lifestyles. ## AI-Driven Interpretation and Literacy * To assist with data translation, the researchers developed a prototype "Insulin Resistance Literacy and Understanding Agent" built on the Gemini family of large language models. * The agent is designed to help users interpret their IR risk predictions and provide personalized, research-backed educational content. * This AI integration aims to facilitate better communication between the data results and actionable health strategies, though it is currently intended for informational and research purposes. By utilizing ubiquitous wearable technology and existing clinical infrastructure, this approach offers a path toward proactive metabolic health monitoring. Integrating these models into consumer or clinical platforms could lower the barrier to early diabetes intervention and enable more personalized preventative care.

google

Highly accurate genome polishing with DeepPolisher: Enhancing the foundation of genomic research (opens in new tab)

DeepPolisher is a deep learning-based genome assembly tool designed to correct base-level errors with high precision, significantly enhancing the accuracy of genomic research. By leveraging a Transformer architecture to analyze sequencing data, the tool reduces total assembly errors by 50% and insertion or deletion (indel) errors by 70%. This advancement is critical for creating near-perfect reference genomes, such as the Human Pangenome Reference, which are essential for identifying disease-causing variants and understanding human evolution. ## Limitations of Current Sequencing Technologies * Genome assembly relies on reading nucleotides (A, T, G, and C), but the microscopic scale of these base pairs makes accurate, large-scale sequencing difficult. * Short-read sequencing methods provide high signal strength but are limited to a few hundred nucleotides because identical DNA clusters eventually desynchronize, blending signals together. * Long-read technologies can sequence tens of thousands of nucleotides but initially suffered from high error rates (~10%); while tools like DeepConsensus have reduced this to 0.1%, further refinement is necessary for high-fidelity reference genomes. * Even a 0.1% error rate results in millions of inaccuracies across the 3-billion-nucleotide human genome, which can cause researchers to miss critical genetic markers or misidentify proteins. ## DeepPolisher Architecture and Training * DeepPolisher is an open-source pipeline adapted from the DeepConsensus model, utilizing a Transformer-based neural network. * The model was trained using a human cell line from the Personal Genomes Project that is estimated to be 99.99999% accurate, providing a "ground truth" for identifying and correcting errors. * The system takes sequenced bases, their associated quality scores, and the orientation of the DNA strands to learn complex error patterns that traditional methods might miss. * By combining sequence reads from multiple DNA molecules of the same individual, the tool iteratively "polishes" the assembly to reach the accuracy required for reference-grade data. ## Impact on Genomic Accuracy and Gene Discovery * The tool’s ability to reduce indel errors by 70% is particularly significant, as these specific errors often interfere with the identification of protein-coding genes. * DeepPolisher has already been integrated into major research efforts, including the enhancement of the Human Pangenome Reference, providing a more robust foundation for clinical diagnostics. * Improved assembly accuracy allows for better mapping of regions where the genome is highly repetitive, which were previously difficult to sequence and assemble confidently. For researchers and bioinformaticians, DeepPolisher represents a vital step in moving from "draft" genomes to high-fidelity references. Adopting this tool in assembly pipelines can drastically improve the reliability of variant calling and gene annotation, especially in complex clinical and evolutionary studies.