Cal BP Research Articles

Tulum’s underwater caves: insights into the oldest human fossils in the Americas

Evidence of late Pleistocene human and fauna remains has been documented within the extensive cave systems of the Tulum region in northeast Yucatán, Mexico. This unique area is vital for paleontological and paleoanthropological research, providing insights into early human adaptation in the Americas. To date, 10 human fossils have been thoroughly studied, with two additional recent discoveries under investigation. These remains, dating from 13,700 to 8,000 BP, emphasize the paleoanthropological significance of Tulum's submerged caves. A key discovery is the skeleton of Eva de Naharon, dated to 13,721 years cal BP, making her the oldest known human fossil in the Americas. Using 3D facial reconstructions and DNA analysis, researchers have identified craniofacial similarities with South Asian populations, suggesting shared ancestry and migration patterns. These findings enrich our understanding of human migration and adaptation. Ongoing research continues to highlight the role of Tulum’s underwater caves in shaping early human history, survival strategies, and social structures over millennia.

IBCFaiCDR: Auxiliary data-driven item-based collaborative filtering in cross-domain RSs to address user cold start problem

The adoption of Recommender Systems (RSs) in various services is imperative in the present era. One of the inherent challenge faced by RSs is the user cold start problem (UCS) and it occurs when there is a lack of enough data available for a new user, which restricts the capacity to provide accurate recommendations. Researchers have conducted investigations into the utilization of auxiliary data like social network data, review text, demographic information etc., to augment the RSs ability to learn and understand the user's preferences, with the aim of solving this issue. The provided information is inadequate due to the restricted level of user engagement within the specified domain. The researchers utilize a Cross-Domain RS (CDR) that incorporates information from multiple domains to provide personalized suggestions to users. Item Based Collaborative Filtering (IBCF), which utilizes item-item similarity, is commonly used when dealing with sparse data. The suggested collaborative filtering technique employs IBCF which uses the item similarity obtained with item features. These features are generated by the proposed approach IBCFaiCDR's model, trained on source domain data such as product images and reviews. The efficacy of the proposed approach is assessed using a large dataset from Amazon, consisting of user interactions across many categories. The results on target domain, evaluated using MAE and RMSE, indicate that the inclusion of auxiliary information (image + text) enhances the RS performance for new users.

Late-Holocene hydroclimatic change and its effect on human activity at Xiada Co on the western Tibetan Plateau

The scarcity of paleoclimate records in the western Tibetan Plateau (TP) hinders our understanding of how environmental evolution affects past human population, agriculture, and animal husbandry. Here, we utilized a range of materials to investigate the impact of climate change on human activities in the Xiada Co basin on the western TP during the Late-Holocene. We presented a continuous compound-specific hydrogen isotope record of sedimentary leaf waxes (δ2Hwax) from a sediment core of Xiada Co, and compared it to XRF core-scanning elements, brGDGT-based mean annual air temperature (MAAT) record, and fecal stanol-based human population proxy record from the same sediment core, as well as archeological evidence from the TP. The δ2Hwax exhibited a sustained increasing trend during the period from 4700 to 900 cal yr BP, followed by a generalized decrease in δ2Hwax values during 900–0 cal yr BP. The multi-proxy analysis of Xiada Co sediments revealed that the δ2Hwax values mainly reflect changes in the ISM precipitation, and are also influenced to some extent by glacier meltwater. Furthermore, a warm and humid climate condition was conducive to human habitation. Appropriate adaptation strategies, such as the herding of cold-tolerant and dry-tolerant sheep and the cultivation of barley in the western TP, led to a surge in population density during 3400–2900 cal yr BP, despite the slightly deteriorated climate background. This study confirmed the importance of choosing the right adaptive strategies to cope with climate change for human survival and development on the Tibetan Plateau.

Stable isotope of Mesolithic remains of Pila wernei of the Nile area, Sudan: A tool for palaeoenvironment reconstruction

The article deals with stable isotopes of oxygen and carbon on current and archaeological semi-aquatic gastropod shell of the Pila wernei from Sudan and reports some new 14C analyses on archaeological Pila specimens. This, with the aim of obtaining new information on climatic and environmental changes in the al-Khiday area during the first phase of Holocene. The Pila shells come from a well-preserved shell midden present at al-Khiday and dated 8700-7000 cal yr BP. The area of al-Khiday was inhabited since at least 10 ka. Pila wernei species has never been studied in detail; this study demonstrates that the O and C isotope composition of aragonite shell is able to record the environmental and diet changes during the gastropod life. The comparison between the isotope data obtained on present-day and archaeological shells show a prevalence of C4 plants and higher rainfall during the Mesolithic. Two climatic fluctuations have been recognised: the first one indicating wetter conditions from 8650-8400 to 8500-8050 cal yr BP (decrease of the δ18O values), the second one pointing less wetter conditions from 8500-8050 to 7850-7600 cal yr BP (increase of δ18O values). Despite the difficulties in studying semi-aquatic gastropods due to their lifestyle habit, the identification of climatic fluctuations in the Early Holocene confirms the reliability of this proxy for climatic reconstructions. Despite the high number of isotopic analyses (1556) used in this work, they were not sufficient to mirror the fast climate changes characterising the studied period and finally obtain a detailed reconstruction for nearly the two millennia considered. Nonetheless, future projects may benefit greatly from unveiling the shell-environment relationship of the species.

The effect of mass and morphology on the mass assembly of galaxies

The pace at which galaxies grew into their current stellar masses and how this growth is regulated is still not fully understood, nor is the role that morphology plays in this process. We applied full spectral fitting techniques with pyPipe3D to the MaNGA sample to obtain its star formation and stellar mass histories and used these to investigate the mass assembly of galaxies by measuring how their specific star formation correlates to their stellar mass at different look-back times. We find that the correlation between these two parameters was shallower in the past. Galaxies used to have similar mass doubling times and the current negative correlation between the specific star formation and M* is primarily due to more massive galaxies ‘dropping’ off the main sequence earlier than less massive ones. Additionally, selecting the galaxies into bins based on their present-day morphology shows a segregation in specific star formation rate (sSFR) that is maintained even at high look-back times, showing that the factors that determine which morphology a galaxy ends up in are in place at very early times. Similarly, selecting them based on their current star formation status shows that, on average, currently retired galaxies used to have slightly a higher sSFR before the drop-off, whereas galaxies that have continued to form stars until today had a lower sSFR initially. We compare our results to a set of cosmic surveys, finding partial agreement in our results with several of them, though with significant offsets in redshift. Finally, we discuss how our results fit with certain theoretical models on galaxy evolution as well as cosmological simulations.

Arabic word tokenization system using the maximum matching model

Word tokenization is the first stage for higher-order Natural Language Processing (NLP) tasks like Part-of-Speech (PoS) tagging, parsing, and named entity recognition. The amount of text on the World Wide Web is growing daily in the present era of technology, necessitating the use of advanced instruments. Since more and more people speak Arabic around the world, Arabic language processing systems must be improved. Due to the writing style of Arabic with a lack of support for capitalization features and the use of compound words, it is difficult to perform word tokenization. This research paper proposes a novel Arabic word tokenization system based on the knowledge. To develop this system, a maximum matching model with its two variations, namely forward and reverse maximum matching is used. The proposed system is implemented in Python. The results produced during system evaluation report high performance.

A Paleoenvironmental Reconstruction of Lake Vrana on the Island of Cres (Croatia) Based on the Geochemistry and Mineralogy of the Late Pleistocene and Holocene Sediments

A 7.4 m long sediment core has been retrieved from the central part of Lake Vrana on the island of Cres to reconstruct the paleoenvironmental conditions. Lake Vrana is the deepest freshwater lake in Croatia, located in the karst region of the eastern Adriatic coast. A dated sediment sequence in Lake Vrana of 4.4 m has spanned the past 16.4 kyr, and it featured a dynamic sediment deposition until the beginning of the Holocene, including strong sediment input and supply to the lake by runoff sediments of dolomitic origin from the catchment in the period 16.4–14.4 cal kyr BP. High organic carbon content, which originates from mixed terrestrial and aquatic origins in the periods 14.4–13.3 cal kyr BP and 12.7–11.7 cal kyr BP, indicates fluctuating lake levels in shallow water environments during the Late Glacial to Holocene transition. The Holocene sequence indicates the development of more stable conditions and continuous sediment deposition, characterized by an increasing trend of siliciclastic sediments delivered into the lake during the early Holocene (11.7–10 cal kyr BP) and dominantly from 8 to 4.4 cal kyr BP, indicating enhanced input and erosion, which coincides with the humid and pluvial period recorded in the central Mediterranean region. It is followed by sediments with high organic carbon content between 4.4 and 1.6 cal kyr BP, which points to higher lake productivity. Calcite sedimentation prevailed between 1.6 to 0.4 cal kyr BP, indicating stable deeper-lake conditions. Predominantly, siliciclastic sediments from 0.4 to 0.1 cal kyr BP pointed to erosion during the Little Ice Age (LIA), with enhanced precipitation and sediment discharge from the catchment. The re-establishment of calcite sedimentation has been observed over the last 100 years.

Influence of transition metal (Cu) and rare earth metal (Dy) co-doping on spinel zinc ferrite (Cu0.1Dy0.08Zn0.9Fe1.92O4) for improved photocatalytic degradation of industrial effluents

In the present era, design and development of novel, highly stable, easily and magnetically separable, cost effective, and visible light driven catalytic material for the removal of harmful industrial effluents is of great importance. In this context, facile co-precipitation route was adopted for the synthesis of ZnFe2O4 (ZFO), Cu0.1Zn0.9Fe2O4 (CZFO), Dy0.08ZnFe1.92O4 (DZFO), and Cu0.1Dy0.08Zn0.9Fe1.92O4 (CDZFO) and their fabrication was confirmed by XRD, FTIR, SEM, and UV-Visible spectroscopy. The phase analysis of all designed materials exhibits that there is an increment in the crystallite size of co-doped zinc ferrite (CDZFO) i.e. 11.51 nm as compared to ZFO (10.74 nm), CZFO (10.92 nm), and DZFO (11.41 nm). The optical study shows a significant decrease in bandgap of CDZFO i.e. 1.82 eV as compared to DZFO (1.89 eV), CZFO (2.0 eV), and ZFO (2.14 eV). This decrease in optical bandgap and increase in crystallite size of the CDZFO is due to the quantum confinement effect. The photocatalytic efficiency of pure, doped, and co-doped samples was investigated against organic dye (Congo red), pharmaceutical drug (ibuprofen), and colorless organic compound (benzoic acid). The photocatalytic results reveal that CDZFO showed about ∼90 % degradation of Congo red while ZFO, CZFO, and DZFO showed only 59 %, 70 %, and 79 % respectively. Moreover, CDZFO also showed highest photocatalytic removal efficiency against ibuprofen (88 %) and benzoic acid (74 %) out of all other synthesized materials. The remarkable photodegradation ability of CDZFO for all targeted pollutants could be attributed to the generation of crystal defects in its lattice, its small bandgap, and higher absorption in visible region. Furthermore, the recyclability experiment confirmed the stability and reusability of the prepared sample.

Traditional Craft Meets Contemporary: Exploring the Potential of Kelarai Bertam Weaving Technique in Modern Furniture Construction

Kelarai Bertam is a traditional weaving method that has been used for ages to make comprehensive weaves for usage both indoors and outdoors in Malaysian homes. This traditional practice, however, is being explored as an innovative method to build modern furniture in response to the increasing need for unique and environmentally friendly designs. Using this detailed weaving technique, designers construct patterns and motifs that combine aesthetic appeal with practicality out of organic materials like rattan, bamboo, and pandan leaves. When applied to contemporary furniture, the outcome's combination of traditional craftsmanship and modern style is fascinating. This combination provides an opportunity to preserve and acknowledge traditional techniques while also emphasising the strength of Malaysian innovation in the present era.

The Actualization of Civic Education as a Solid Foundation for Youth in Countering Secularism

Civic Education holds significant importance as a scientific field in cultivating the moral values of the Indonesian population and shaping the future image of the country. In the present era, there is an urgent need for Civic Education among the Indonesian people, particularly the youth, to establish a solid national foundation and develop noble character traits that will protect them from the influence of secularism pervading society. Secularism is viewed as a formidable adversary to the Indonesian people, and it is crucial to prevent the younger generation from embracing such ideas within the boundaries of the Indonesian state. This article adopts a literature review approach, incorporating articles from various credible sources such as SAGE Journal, Google Scholar, and relevant books, in order to enhance the credibility and accuracy of the research findings. The outcomes of this study will comprehensively illustrate the implementation of Civic Education as a means to empower youth in firmly opposing the spread of secularism in Indonesia. The role of youth in shaping the nation's civilization is of utmost significance, as they serve as the vanguard in safeguarding against the encroachment of secularism and strive towards realizing the national ideals of independence, unity, sovereignty, justice, and prosperity

Democrazia fiscale e finanziamento delle religioni. Le campagne pubblicitarie per l’8xmille della Chiesa cattolica: dalla rendicontazione alla promozione

Fiscal democracy and the financing of religions. The advertising campaigns for the Catholic Church's 8xmille: from reporting to promotion ABSTRACT: On the eve of the fortieth anniversary of the law (No. 222 of 1985) that introduced a new regulatory framework for the Catholic Church's financial system, which was subsequently extended to other religious groups, presents an opportunity to reflect on the significance and utility of the revisions introduced from the Villa Madama Agreement and to evaluate the ongoing critical issues raised by doctrinal and legal developments in light of recent developments. In the present era, while some doubts appear to have reached a state of equilibrium with regard to the stability of the data, others have the effect of introducing a certain degree of uncertainty. An analysis of the issues pertaining to advertising and reporting reveals a tendency on the part of the Catholic Church to focus less on the primary driver of change, namely the sustenance of the clergy, and instead direct attention towards welfare interventions that bear resemblance to those typically undertaken by Third Sector entities. The persistence of old doubts and the emergence of new challenges, it is pertinent to assess whether the consolidated 8xmille mechanism remains a viable and effective response to the prevailing circumstances. SOMMARIO: 1. I (quasi) quarant’anni dell’8xmille - 2. Il sistema di finanziamento pubblico della Chiesa cattolica. Un prima e un dopo - 3. Come funziona l’8xmille? Le aporie di un sistema tra punti di forza e punti di debolezza - 4. “Dati alla mano”. La rendicontazione CEI 2023 - 5. Diritto, religioni e pubblicità - 6. Gli spot 8xmille - 7. Quale futuro per il finanziamento delle religioni?

Scylla. II. The Spatially Resolved Star Formation History of the Large Magellanic Cloud Reveals an Inverted Radial Age Gradient

The proximity of the Magellanic Clouds provides the opportunity to study interacting dwarf galaxies near a massive host, and spatial trends in their stellar population properties in particular, with a unique level of detail. The Scylla pure parallel program has obtained deep (80% complete to >1 mag below the ancient main-sequence turnoff), homogeneous two-filter Hubble Space Telescope imaging sampling the inner star-forming disk of the Large Magellanic Cloud (LMC), the perfect complement to shallower, contiguous ground-based surveys. We harness this imaging together with extant archival data and fit lifetime star formation histories (SFHs) to resolved color–magnitude diagrams of 111 individual fields, using three different stellar evolutionary libraries. We validate per-field recovered distances and extinctions, as well as the combined global LMC age–metallicity relation and SFH against independent estimates. We find that the present-day radial age gradient reverses from an inside-out gradient in the inner disk to an outside-in gradient beyond ∼2 disk scale lengths, supported by ground-based measurements. The gradients become relatively flatter at earlier look-back times, while the location of the inversion remains constant over an order of magnitude in look-back time, from ∼1 to 10 Gyr. This suggests at least one mechanism that predates the recent intense LMC–Small Magellanic Cloud interaction. We compare observed radial age trends to other late-type galaxies at fixed stellar mass and discuss similarities and differences in the context of potential drivers, implying strong radial migration in the LMC.

Scylla. III. The Outside-in Radial Age Gradient in the Small Magellanic Cloud and the Star Formation Histories of the Main Body, Wing, and Outer Regions

The proximity of the Large and Small Magellanic Clouds (LMC and SMC) provides the opportunity to study the impact of dwarf–dwarf interactions on their mass assembly with a unique level of detail. To this end, we analyze two-filter broadband imaging of 83 Hubble Space Telescope (HST) pointings covering 0.203 deg2 toward the SMC, extending out to ∼3.5 kpc in projection from its optical center. Lifetime star formation histories (SFHs) fit to each pointing independently reveal an outside-in age gradient such that fields in the SMC outskirts are older on average. We measure radial gradients of the look-back time to form 90%, 75%, and 50% of the cumulative stellar mass for the first time, finding δ(τ 90, τ 75, τ 50)/δ R = (0.61 −0.07+0.08 , 0.65−0.08+0.09 , 0.82−0.16+0.12 ) Gyr kpc−1 assuming PARSEC evolutionary models and a commonly used elliptical geometry of the SMC, although our results are robust to these assumptions. The wing of the SMC deviates from this trend, forming 25% of its cumulative mass over the most recent 3 Gyr owing to a best-fit star formation rate that remains approximately constant. Our results are consistent with chemodynamical evidence of a tidally stripped SMC component in the foreground and imply contributions to the observed SFH from multiple previous LMC–SMC interactions. We also compare our SMC SFH with results from a companion study of the LMC, finding that while the two galaxies present different internal, spatially resolved SFH trends, both the LMC and SMC have similar near-constant lifetime SFHs when viewed globally.

Euclid II. The VIS instrument

This paper presents the specification, design, and development of the Visible Camera (VIS) on the European Space Agency's mission. VIS is a large optical-band imager with a field of view of 0.54 deg$^2$ sampled at with an array of 609 Megapixels and a spatial resolution of . It will be used to survey approximately 14 000 deg$^2$ of extragalactic sky to measure the distortion of galaxies in the redshift range $z=0.1$--1.5 resulting from weak gravitational lensing, one of the two principal cosmology probes leveraged by With photometric redshifts, the distribution of dark matter can be mapped in three dimensions, and the extent to which this has changed with look-back time can be used to constrain the nature of dark energy and theories of gravity. The entire VIS focal plane will be transmitted to provide the largest images of the Universe from space to date, specified to reach AB with a signal-to-noise ratio S/N in a single broad E (r+i+z)$ band over a six-year survey. The particularly challenging aspects of the instrument are the control and calibration of observational biases, which lead to stringent performance requirements and calibration regimes. With its combination of spatial resolution, calibration knowledge, depth, and area covering most of the extra-Galactic sky, VIS will also provide a legacy data set for many other fields. This paper discusses the rationale behind the conception of VIS and describes the instrument design and development, before reporting the prelaunch performance derived from ground calibrations and brief results from the in-orbit commissioning. VIS should reach fainter than AB =25$ with $ S/N 10$ for galaxies with a full width at half maximum of in a diameter aperture over the Wide Survey, and $m_ AB for a Deep Survey that will cover more than 50 deg$^2$. The paper also describes how the instrument works with the telescope and survey, and with the science data processing, to extract the cosmological information.

Protection Mechanisms and Revitalization Strategies for Industrial Heritage

Industrial heritage is a product of the Industrial Revolution and an important asset for a country or region. The protection and revitalization of industrial heritage have become pressing tasks in the present era. In the new era, it is essential, on the one hand, to establish a comprehensive and scientific policy system for industrial heritage protection by creating specialized protection agencies and ensuring strong governmental support. On the other hand, revitalization strategies should be developed based on practical needs, such as transforming industrial heritage into cultural and art centers, converting it into creative industry parks, and integrating industrial heritage resources into tourism and leisure industries. These strategies aim to ensure the comprehensive protection and sustainable use of industrial heritage.

Effect of the local and large-scale environment on the star formation histories of galaxies

The specific environment of galaxies may play a key role in their evolution. Large extragalactic surveys make it possible to study galaxies not only within their local environment, but also within the large-scale structure of the Universe. We aim to investigate how the local environment influences the star formation history (SFH) of galaxies across a range of large-scale environments. We categorised a sample of 9384 galaxies into the three primary large-scale structures (voids, walls and filaments, and clusters). We further classified them based on their local environment (as either 'singlets' or group members) through a search of companion galaxies within sky-projected distances of $ r_p < 0.45$ Mpc and velocity differences of $ v < 160$ $ km s $. Subsequently, we explored these subsamples using SFH data from previous works. Throughout this study, we divided galaxies into long-timescale SFH galaxies (LT-SFH), which assemble their mass steadily along cosmic time, and short-timescale SFH galaxies (ST-SFH), which form their stars early on. We then compared their characteristic mass assembly look-back times. The distributions of mass assembly look-back times in ST-SFH galaxies are statistically different for singlets and groups. These differences are only found in LT-SFH galaxies when studying these distributions in stellar mass bins. Our results indicate that the large-scale environment is related to a delay in mass assembly of up to sim 2 Gyr, while this delay is $<$1 Gyr in the case of local environment. The effects of both types of environment are more significant in less massive galaxies and in LT-SFHs. Our results are consistent with galaxies in groups assembling their stellar mass earlier than in singlets, especially in voids and lower mass galaxies. Local environment plays a relevant role in stellar mass assembly times, although we find that large-scale structures also cause a delay in mass assembly, and all the more so in the case of cluster galaxies.

Big Data as An Emerging Paradigm in Organisations' Management: A Bibliometric Analysis

The Big Data Age defines the present era, and the globalisation of business makes it pressing to derive valuable insights from data so that organisations can make sustained decisions. There is no consensus in the literature on how organisations should guide the vast volume of data in value creation or galvanise performance gains. The study aims to address these gaps by reviewing the literature searching WoS using R. Bibliometrix. 4,019 documents were identified between 2008 and early February 2022 through a current mapping of Big Data in management. The results indicate a strong collaboration network among authors and a notable trend in Big Data, Big Data Analytics, Machine Learning, and Artificial Intelligence. These keywords reveal a concern for the predictive analysis of data and the emergence of new research trends, namely management, performance, decision-making, business and value creation, supporting the thesis that Big Data is an emerging paradigm in organisational management.

Unravelling 6000 years of interplay among environmental changes, anthropogenic activities, and Vesuvius eruptions in the upper Sarno Plain (Campania, Italy)

Abstract Pollen analysis was carried out on the infilling succession of the Fossa San Vito sinkhole, at the NE foothills of the Sarno Plain (Italy). Four 14C dates and six tephra layers constrain the pollen sequence between ca. 6000 and 500 cal yr BP. A forested environment, with a few signs of human activities, characterizes the pre-protohistoric period (ca. 6000–2750 yr BP). Stability of the arboreal pollen grains to non-arboreal pollen grains (AP/NAP) curve is due to climate-related opposite oscillations of deciduous and evergreen forest. In this period, the pyroclastic products from Neapolitan volcanoes that reached the upper Sarno Plain seem to have affected neither vegetation nor human activities. In the archaic and classic periods (ca. 2750–1500 yr BP), intensive deforestation and increase in anthropogenic indicators indicate the occurrence of grazing and crop activities managed by the main urban centers located in the plain: Pompeii, Stabiae, and Nuceria. After the Pompeii eruption in CE 79, a rapid re-afforestation and decline in all anthropogenic indicators testify to the temporary abandonment of the area, linked to the disastrous demise of the main economic centers. The upper plain was repopulated and exploited in the Late Ancient and Middle Ages (ca. 1700–500 yr BP), as indicated by the increase in all crop and grazing indicators.

Ancient Fishing Strategies for the Extinct Thicktail Chub (Gila crassicauda) in the Sacramento-San Joaquin Delta

ABSTRACT Now extinct, Thicktail chub (Gila crassicauda) was endemic to central California and was a key component of local fisheries before the 1800s. Little is known about their biology, behavior, ecology, or role in precontact Native American fisheries. Archaeological sites contain large numbers of thicktail chub bones and represent a key source of data to fill our considerable gap in knowledge. We developed regression equations to convert thicktail chub skeletal elements to estimates of standard length (SL). Bones from two contemporaneous precontact Late Period (ca 700 -200 cal BP) sites, CA-CCO-138, and CA-CCO-647, in the Sacramento-San Joaquin Delta, show that precontact thicktail chub achieved a maximum standard length (SL) of 306 mm. Bone size distributions suggest spearing was the most likely capture technique, likely during a spring-summer nearshore fishery. The results contribute vital information to thicktail chub historical ecology and their key role in precontact Indigenous fisheries.

Dwelling architecture and flexible land-use strategies in the Prehispanic Sierras de Córdoba, Argentina

The article examines the evidence of architecture recovered from the Late Prehispanic Period of the Sierras de Córdoba (∼1220–330 cal BP), Argentina. We explore the relationship between household architecture and the level of residential mobility, arguing that a flexible subsistence and mobility pattern followed the adoption of plant cultivation and not entirely sedentary farming. The architectural evidence presented structures made using low-energy construction techniques that were not intended for an anticipated long-term occupation. This architecture meets the expectation of a settlement pattern left by groups that were occasional food producers and used specific locations as seasonal campsites, indicating a flexible landscape-use organization.