Prior Occupancy Research Articles

A high-precision radiocarbon chronology of Inka rule in the Upper Loa River Region of northern Chile

Abstract The chronology of the Inka Empire is poorly resolved, with most scholars utilizing a post hoc ethnohistoric reconstruction of imperial expansion as a common reference point. Radiocarbon-based analyses can now accomplish sufficient resolution for meaningful independent estimates of Inka chronology, however, and it is incumbent upon archaeologists to develop such appraisals. Here we produce a Bayesian analysis of radiocarbon data from the Upper Loa River area of northern Chile to estimate the timing of Inka incorporation of this region. In order to accurately associate samples with Inka rule, only radiocarbon dates from Inka sites without prior occupations are used (n = 34), producing a model for the onset of Inka rule of AD 1401–1437 (95% hpd) with a median date of AD 1420. This estimate is further used as a point of comparison for understanding diachronic imperial processes in the region. Site-level models of a variety of site types indicate that the Inka rapidly founded several administrative/mining bases at the onset, followed by the addition of smaller infrastructure components during a second pulse of activity near the middle of the 15th century. Date assemblages at the agricultural sites of Topaín and Paniri also indicate a decline in activity at the former and an increase in activity at the latter from early on in Inka rule. These results provide a high-resolution data point for reconstructing Inka imperial chronology, and expanding such studies will be essential to understanding processes of Inka imperialism at larger scales.

Transfer and persistence of intruder DNA within an office after reuse by owner

The heightened sensitivity of DNA typing techniques, paired with the extensive use of trace DNA in forensic investigations, has resulted in an increased need to understand how and when DNA is deposited on surfaces of interest. This study focussed on the transfer, persistence, and prevalence of trace DNA in a single occupation of an office space by an intruder, when all contacts made during occupation and for the two hours prior and post occupation were known. The extent to which DNA could be recovered from contacted/not contacted surfaces was investigated. This study investigates the impacts of these movements and use of an office space when the duration of occupancy, surface contact histories and shedder status of participants are known. Contacts were documented and surfaces in the office space were targeted for sampling. Categories were set for target sampling that included different types of contact. Direct and indirect DNA transfer was detected in 55 % and 6 % of samples, respectively. Contactless DNA transfer was detected in 0.5 % of samples. The owner was observed as the sole/major/majority contributor in 77 % of the samples and as minor contributor in 10 % of samples. The intruder was observed as the sole/major/majority contributor in 14 % of samples and as the minor contributor in 16 %. An increased number of contacts increased the relative DNA contribution of the individual making the contact, however, not all observed direct contacts resulted in detectable DNA transfer. The outcome of this study will aid in better sample targeting strategies and contribute to the pool of data assisting in the development of activity level assessments.

Evolution of leapfrog migration: A test of competition-based hypotheses.

Leapfrog migration is a common migration pattern in birds where the breeding and wintering latitudes between populations are in reversed latitudinal sequence. Competition for wintering and breeding sites has been suggested to be an ultimate factor, and several competitor-based hypotheses have been proposed to explain this pattern. If wintering sites close to the breeding sites are favored, competitive exclusion could force subdominant individuals to winter further away. Competitive exclusion could be mediated either through body size or by prior occupancy. The alternative "spring predictability" hypothesis assumes competition for sufficiently close wintering areas, allowing the birds to use autocorrelated weather cues to optimally time spring migration departure. To test predictions and assumptions of these hypotheses, we combined morphometrics, migration, and weather data from four populations of common ringed plover breeding along a latitudinal (56-68° N) and climatic gradient (temperate to Arctic). Critical for our evaluation was that two populations were breeding on the same latitude in subarctic Sweden with the same distance to the closest potential wintering site, but differed in breeding phenology, and wintered in West Africa and Europe, respectively. Thus, while breeding on the same latitude, their winter distribution overlapped with that of an Arctic and temperate population. Body size was largest within the temperate population, but there was no size difference between the two subarctic populations. Populations wintering in Europe arrived there before populations wintering in Africa. The largest variation in the arrival of meteorological spring occurred at the temperate breeding site, while there was almost no difference among the other sites. In general, temperatures at the northernmost wintering area correlated well with each breeding site prior to breeding site-specific spring arrival. Based on these observations, we conclude that competitive exclusion through body-size-related dominance cannot explain leapfrog migration. Furthermore, the assumptions on which the "spring predictability" hypothesis is based did not match the observed wintering ranges either. However, we could not reject the hypothesis that competitive exclusion mediated by prior occupancy in the wintering area could lead to leapfrog migration, and therefore, this hypothesis should be retained as working hypothesis for further work.

Seasonal Variation in First Territory Settlement of Dispersing Golden Eagles: An Innate Behaviour?

Despite advancements through satellite telemetry, knowledge of the behaviour and ecology of large raptors during natal dispersal is still poor, even though this transience phase is important in understanding the population dynamics and conservation of these keystone species. After this phase, which can take several years, the subsequent rapid transitional event on first territory settlement is less studied. It apparently occurs earlier without competition from existing territory occupants. The time of year when young large raptors settle on a territory has rarely been addressed empirically. Our study of seasonal timing of first settlement used data from 46 golden eagles GPS-tagged as nestlings in Scotland which were tracked to their first territory settlement, as adjudged by a robust algorithmic method. We show that when young golden eagles occupied their first territory, their settlements were uncommon in summer and most common in late winter/spring, but also occurred in autumn into early winter. The significant seasonal pattern was consistent, regardless of the probable prior occupancy status (vacant/occupied) of the settled territory (respectively, the likely absence or presence of defending territorial birds). This showed that seasonal territory settlement was unlikely to be related to any response from territory occupants. It infers further that seasonality in first territory settlement was underpinned by innate behaviours in dispersing eagles. Seasonal distribution of settlement dates was significantly different between sexes, with males more likely to settle in autumn, predominantly in prior vacant territories. We speculate on potential causative drivers behind our results and conclude that more research is clearly needed in this field of study.

Risk of organism acquisition from prior room occupants: An updated systematic review.

Evidence from a previous systematic review indicates that patients admitted to a room where the previous occupant had a multidrug-resistant bacterial infection resulted in an increased risk of subsequent colonisation and infection with the same organism for the next room occupant. In this paper, we have sought to expand and update this review. A systematic review and meta-analysis was undertaken. A search using Medline/PubMed, Cochrane and CINHAL databases was conducted. Risk of bias was assessed by the ROB-2 tool for randomised control studies and ROBIN-I for non-randomised studies. From 5175 identified, 12 papers from 11 studies were included in the review for analysis. From 28,299 patients who were admitted into a room where the prior room occupant had any of the organisms of interest, 651 (2.3%) were shown to acquire the same species of organism. In contrast, 981,865 patients were admitted to a room where the prior occupant did not have an organism of interest, 3818 (0.39%) acquired an organism(s). The pooled acquisition odds ratio (OR) for all the organisms across all studies was 2.45 (95% CI: 1.53-3.93]. There was heterogeneity between the studies (I2 89%, P<0.001). The pooled OR for all the pathogens in this latest review has increased since the original review. Findings from our review provide some evidence to help inform a risk management approach when determining patient room allocation. The risk of pathogen acquisition appears to remain high, supporting the need for continued investment in this area.

Concerning emergence of a new vancomycin-resistant Enterococcus faecium strain ST1299/CT1903/vanA at a tertiary university centre in South Germany

vanB-carrying vancomycin-resistant Enterococcus faecium (VREfm) of the sequence types 80 (ST80) and ST117 have dominated Germany in the past. In 2020, our hospital witnessed a sharp increase in the proportion of vanA-positive VREfm. To attempt to understand these dynamics through whole-genome sequencing (WGS) and analysis of nosocomial transmissions. At our hospital, the first VREfm isolate per patient, treated during 2020, was analysed retrospectively using specific vanA/vanB PCR, WGS, multi-locus sequence typing (MLST), and core-genome (cg) MLST. Epidemiologic links between VRE-positive patients were assessed using hospital occupancy data. Isolates from 319 out of 356 VREfm patients were available for WGS, of which 181 (56.7%) fulfilled the ECDC definition for nosocomial transmission. The high load of nosocomial cases is reflected in the overall high clonality rate with only three dominating sequence (ST) and complex types (CT), respectively: the new emerging strain ST1299 (100% vanA, 77.4% CT1903), and the well-known ST80 (90.0% vanB, 81.0% CT1065) and ST117 (78.0% vanB, 65.0% CT71). The ST1299 isolates overall, and the subtype CT1903 in particular, showed high isolate clonality, which demonstrates impressively high spreading potential. Overall, 152 out of 319 isolates had an allelic cgMLST difference of ≤3 to another, including 91 (59.6%) ST1299. Occupancy data identified shared rooms (3.7%), shared departments (6.2%), and VRE-colonized prior room occupants (0.6%) within 30 days before diagnosis as solid epidemiological links. A new emerging VREfm clone, ST1299/CT1903/vanA, dominated our institution in 2020 and has been an important driver of the increasing VREfm rates.

Lifting Wavelet-Assisted EM Joint Estimation and Detection in Cooperative Spectrum Sensing.

Spectrum sensing in Cognitive radio (CR) is a way to improve spectrum utilization by detecting spectral holes to achieve a dynamic allocation of spectrum resources. As it is often difficult to obtain accurate wireless environment information in real-world scenarios, the detection performance is limited. Signal-to-noise ratio (SNR), noise variance, and channel prior occupancy rate are critical parameters in wireless spectrum sensing. However, obtaining these parameter values in advance is challenging in practical scenarios. A lifting wavelet-assisted Expectation-Maximization (EM) joint estimation and detection method is proposed to estimate multiple parameters and achieve full-blind detection, which uses lifting wavelet in noise variance estimation to improve detection probability and convergence speed. Moreover, a stream learning strategy is used in estimating SNR and channel prior occupancy rate to fit the scenario where the SU has mobility. The simulation results demonstrate that the proposed method can achieve comparable detection performance to the semi-blind EM method.

Transitioning from industry to teaching in VET: profiles of VET teachers in Chile

PurposeSituated in the Chilean context, this study investigates how Vocational Education and Training (VET) teacher profiles, based on their perceptions of prior work experience in industry, relate to their current motivation and perception of teaching in VET. By doing so, the authors seek to provide valuable evidence to inform the development of policies to attract and maintain well-qualified teachers from industry in Chile and other countries facing similar changes.Design/methodology/approachThe authors used a descriptive cross-sectional design to collect data from 660 VET teachers using a two-scale instrument: Perception of Prior Occupation (PPO) and adapted FIT-Choice scales. By adopting a typological approach, the authors constructed profiles of VET teachers based on their perception of past industry experience. The authors then analyzed how these profiles vary regarding individual teacher characteristics, motivation and perception of teaching in VET.FindingsThe authors found a significant degree of heterogeneity among VET teachers' prior industry experiences, leading them to identify three distinct VET teacher profiles: “High Perception of Prior Occupation,” “Learning and Teaching-Oriented” and “Low Perception of Prior Occupation.” Notably, the most distinguishing characteristics across these profiles were age, VET teaching area, holding a job outside of teaching and years of prior industry experience. Furthermore, the authors found that motivation and perceptions of teaching varied significantly across these VET teacher profiles.Originality/valueThere needs to be more research on the factors that attract and retain industry workers as VET teachers in high schools. This study is among the first to address this topic in a non-European context.

Defect mechanisms, oxygen vacancy trapping ability in rare‐earth doped BaTiO3 from first‐principles and thermodynamics

AbstractThe defect mechanisms of rare earth (RE) doped BaTiO3 have a strong impact on the electrical performance of the multilayer ceramics capacitors (MLCCs). Oxygen vacancy is the main reason for the device degradation over longtime use, while the effect of the doping strategy on controlling the oxygen vacancies is not yet quantitatively understood. In this work, the grand canonical thermodynamic defect model based on first‐principle calculations is applied to evaluate the defect mechanism of RE‐doped BaTiO3 under practical experimental condition. The charge compensation and prior site occupancy of RE are found not only associated with ionic size but also exhibit transitions with oxygen partial pressure and doping concentration. Furthermore, the oxygen vacancy trapping ability of RE ions is evaluated from the perspectives of thermodynamics and kinetics. The migration barrier among first nearest oxygen sites dramatically changed depending on the RE site occupancy. The large trapping ability is contributed by the relatively large negative binding energy of the defect complex and comparable RE concentrations substituted on Ba and Ti sites. The two conditions can be achieved in amphoteric ions doped systems, while in pure donor doped BT only one of these conditions can be satisfied. Although the self‐compensated defect complexes exhibit the highest binding energy, the trapping ability contributed by different defect complexes (, , REBa − RETi) is generally comparable in these systems. This feature of amphoteric RE ions accounts for the improvement of the lifetime and reliability of MLCCs.

Redefining radiocarpal fracture-dislocations with injury specific management and a clinical classification system: a retrospective review.

Unlike articular shear fractures of the distal radius, radiocarpal fracture-dislocations defined as complete dislocation of the lunate from its articular facet of the radius are relatively uncommon. The management principles of these fractures have not been defined and there is no consensus on approach to management of these injuries. The aim of this study is to review our series of radiocarpal fracture-dislocations and propose a radiographic classification to guide surgical management. This study is reported based on STROBE guidelines. A total of 12 patients underwent open reduction and internal fixation. All the fracture-dislocations were dorsal and satisfactory objective outcomes achieved were comparable to literature. Injury morphology-specific management approach was used based on the size of dorsal lip fragment and the volar teardrop fragment attached to the short radiolunate ligament assessed by preoperative CT scans. All patients with known outcome (n = 10) went on to resume their prior occupation and hobbies that included high-demand activities and manual labour at mean follow-up of 27 weeks. Average wrist flexion was 43° and wrist extension was 41° while radial and ulnar deviation were 14° and 18° respectively. Average forearm pronation was 76° and supination was 64° at final follow-up. We describe four injury patterns of radiocarpal fracture-dislocations based on preoperative CT scans that guide fixation. We believe that early recognition of radiocarpal fracture-dislocations and appropriate management can yield satisfactory outcomes.

Discovery of unknown new ponds occupied by the endangered giant water bug Kirkaldyia deyrolli (Hemiptera: Heteroptera: Belostomatidae) by combining environmental DNA and capture surveys

AbstractBasic ecological information (e.g. habitat or distribution) is indispensable for conserving endangered species. The giant water bug Kirkaldyia deyrolli is an aquatic insect in the large stink bug family (Belostomatidae). It inhabits ponds and is a critically endangered species. In this study, we developed a species‐specific primer–probe set (the cytochrome c oxidase I region in mitochondrial DNA) that was used in real‐time polymerase chain reaction (PCR) assays to detect K. deyrolli environmental DNA (eDNA). Next, using eDNA analysis, we investigated the presence of K. deyrolli in 89 study ponds (including one pond that had already been identified as the habitat of this species) in Shimane Prefecture, Japan. The eDNA of K. deyrolli was detected in 11 of these 89 ponds. Furthermore, when the traditional method of direct capture survey was carried out in four of the 10 ponds where K. deyrolli eDNA had been detected and no prior occupancy information for this species was available, the capture of one K. deyrolli (female) was successful in only one pond. This study showed that combining eDNA analysis and direct capture methods can lead to discovering previously unknown habitats essential for conserving an endangered species.

Technological Change and the Consequences of Job Loss

We examine the role of technological change in explaining the large and persistent decline in earnings following job loss. Using detailed skill requirements from the near universe of online vacancies, we estimate technological change by occupation and find that technological change accounts for 45 percent of the decline in earnings after job loss. Technological change lowers earnings after job loss by requiring workers to have new skills to perform newly created jobs in their prior occupation. When workers lack the required skills, they move to occupations where their skills are still employable but are paid a lower wage. (JEL J24, J31, J63, O33)

Who Becomes a Foreign Fighter? Characteristics of the Islamic State’s Soldiers

ABSTRACT Contemporary conflicts are becoming increasingly transnational in nature. In particular, individuals are leaving their homelands to participate in foreign conflicts at an unprecedented rate. This paper analyzes the foreign fighter phenomenon in the context of the Islamic State. Using primary source data on individual ISIS members from the Middle East, this paper contributes to the literature with two key findings. The first affirms previous work on terrorist participants and finds that those who join the Islamic State are more educated and younger than others from the same country. Second, other characteristics that are thought to correlate with joining a terrorist organization, such as prior occupation and marital status, have an inconsistent association and vary by country. Specifically, individuals with a university education and who also hold an unskilled job have the highest likelihood of joining ISIS. Overall, the results suggest that relative deprivation drives participation in foreign fighting.

‘Droughts and Flooding Rains’: Ecology and Australian Theatre in the 1950s

This article uses historical-ecological insights for a re-reading of two little-known mid-twentieth-century Australian plays, Oriel Gray’s The Torrents and Eunice Hanger’s Flood, which highlight developments relevant to the environmental disasters of today. In particular, the article focuses on the significance of key cultural assumptions embedded in the texts – and a revival of The Torrents in 2019 – including those to do with land use in a period of accelerating development. This approach offers new insights into the dominance of mining, irrigation, and dam-building activities within the Australian ethos, landscape, and economy. One of these insights is the framing of development as progressive. The article thus also examines how development projected as progressive takes place amid the continuing denial of prior occupation of the land by First Nations peoples and of knowledge systems developed over thousands of years. The intersectional settler-colonialist-ecocritical approach here seeks to capture the compounding ecosystem that is modern Australian theatre and its critique. The intention is not to apply revisionist critiques of 1950s plays but to explore the historical relationship between humans, colonialism, and the physical environment over time. Denise Varney is Professor of Theatre Studies in the School of Culture and Communication at the University of Melbourne. Her research is in modern and contemporary theatre and performance, with published work in the areas of ecocriticism, feminism, and Australian theatre. Her most recent book is Patrick White’s Theatre: Australian Modernism on Stage 1960–2018 (Sydney University Press, 2021).

Transfer of Extended Spectrum Cephalosporin Resistant Enterobacteriaceae Among Patients on an HSCT Unit and the Value of Surveillance and Contact Isolation

The mechanism(s) of acquisition of extended-spectrum cephalosporin-resistant Enterobacteriaceae (ESCRE) on inpatient hospital units dedicated to hematopoietic stem cell transplantation (HSCT) is unclear. The objectives of this study were to determine whether ESCRE organisms are transmitted among patients housed on a HSCT unit, clarify the mechanisms involved, and determine whether routine surveillance for ESCRE carriage and contact isolation for ESCRE carriers is beneficial. The study was conducted on a 30-bed inpatient unit dedicated to the care of patients with hematologic malignancies and HSCT recipients. To investigate whether ESCRE organisms may be transmitted vertically to subsequent room occupants, presumably through contamination of room surfaces, we (1) cultured 6 high touch areas in 10 rooms before and 9 rooms after terminal cleaning that had been occupied by patients with ESCRE carriage, (2) determined the in vitro survivals of our most common clinical ESCRE species, and (3) followed the subsequent room occupants of 54 consecutive ESCRE colonized patients for the development of inpatient acquired ESCRE carriage. To investigate whether ESCRE organisms are transmitted horizontally among inpatients we (1) sequenced 60 available ESCRE Escherichia coli isolates obtained from unit inpatients and searched for identities using complete-genome multisequence locus typing (cgMLST) and (2) retrospectively tabulated the cumulative rates of acquired ESCRE carriage in 356 patients admitted for a first HSCT before (200 patients) or after (156 patients) institution of universal ESCRE stool surveillance and contact isolation for carriers. No ESCRE organisms were cultured from patient rooms before or after terminal cleaning. In vitro, few, if any, ESCRE organisms survived longer than 2 hours. Nine of the subsequent occupants of a room in which a patient with ESCRE carriage had resided were detected with ESCRE carriage, only 2 of whom carried the same species as that of the prior occupant. DNA sequencing and cgMLST determination of the 60 E. coli isolates showed 53 cgMLST strains. Seven of the 53 strains were shared by 2 patients. After institution of universal ESCRE surveillance/isolation there was a significant decline in acquired ESCRE carriage among HSCT recipients. We conclude that vertical transmission of ESCRE organisms through room contamination appears to be uncommon on modern HSCT units. Conversely, our results are consistent with the horizontal spread of ESCRE organisms, probably mediated by intermediate vectors such as personnel or shared equipment. Further studies are needed to better define the magnitude of and risk factors for ESCRE horizontal transfers and the benefits of ESCRE surveillance/isolation.

‘The real history of the country’? Expropriation without Compensation and Competing Master Narratives about Land (Dis)Possession in South Africa

In 2018, South African President Cyril Ramaphosa announced his government’s intention to pursue land expropriation without compensation. In a country where wealth and poverty still run largely along apartheid-era racial lines, this policy is widely associated with transferring white-owned agricultural property to landless and impoverished blacks. As with preceding land reform policy, expropriation without compensation is informed by a ‘master narrative’ of 20th-century black dispossession through rural land loss, urban forced removals and impoverishment. This article highlights how the recent revitalisation of the land debate has stimulated the more assertive articulation of competing historical narratives of land (dis)possession. We scrutinise such alternative master narratives emanating from two groups claiming to represent marginalised minorities whose identity and experience differ from that of black South Africans: Khoisan activists who mobilise discourses of indigeneity and prior occupancy, and the Afrikaner interest group AfriForum, which deploys discourses of expertise, rationality and impartiality to legitimise their representations of the past. Despite vast differences in the nature of these movements as well as the historical narratives they advance, they have shown instances of mutual support and apparent co-operation. We trace these to key intersections in their historical narratives and the opportunities these offer in the context of the ANC’s flagging electoral support. Understanding how master narratives compete is not only necessary to appraise South Africa’s current political juncture – it equally reveals how citizens who feel excluded and marginalised turn to history to carve out space, legitimacy and support for their agendas in this fraught environment.

Place-name wars in Karabakh: Russian Imperial maps and political legitimacy in the Caucasus

ABSTRACT Place names play important ideological role in the modern Armenian–Azerbaijani conflict over Karabakh. Both sides use toponymic evidence to claim a prior occupation of the disputed territory. Azerbaijan relies on the Russian maps to prove that the Armenian population are recent newcomers. Armenians point out to the medieval documents to prove the opposite. This article attempts to reconcile the contradictory evidence used by both sides by looking at the transformation of place-naming practises in the wake of the emergence of a modern bureaucratic state. I argue that before the rise of modern bureaucratic state in Europe the place-naming was not within the realm of the state interest. The Russian conquest brought the uniformity of toponymic landscape into Caucasus where several toponymic landscapes coexisted in time and space. This resulted in elevation of one landscape into an official landscape and silencing of the other.

Khoisan Consciousness: Articulating Indigeneity in Post-Apartheid Cape Town

Abstract The Khoisan were decimated, dispossessed and assimilated into the mixed-race “Coloured” group during colonialism and apartheid, spawning the notion of their supposed extinction. However, Cape Town, where colonial history runs deepest, became the epicentre of “Khoisan revivalism” after apartheid. Khoisan revivalists reject Coloured identity and campaign for cultural development, historical justice and indigenous rights. Many also claim land and traditional leadership titles. Drawing on ethnographic fieldwork among Khoisan revivalists, my PhD dissertation scrutinises Khoisan revivalism’s origins, appeal and political aspirations. It focuses on the various ways that historical events, figures and practices inform diverse articulations of indigeneity. Khoisan revivalists are primarily seeking a relatable connection with the past and select sources, mediums and content accordingly. Moreover, in simultaneously replicating, disregarding and appropriating colonial representations, they produce a “subversive authenticity”. While empowering to many, Khoisan revivalism has also emboldened some to mobilise a racialised identity politics based on prior occupancy, which today extends beyond the movement.

Human practices behind the aquatic and terrestrial ecological decoupling to climate change in the tropical Andes

Anthropogenic climate change and landscape alteration are two of the most important threats to the terrestrial and aquatic ecosystems of the tropical Americas, thus jeopardizing water and soil resources for millions of people in the Andean nations. Understanding how aquatic ecosystems will respond to anthropogenic stressors and accelerated warming requires shifting from short-term and static to long-term, dynamic characterizations of human-terrestrial-aquatic relationships. Here we use sediment records from Lake Llaviucu, a tropical mountain Andean lake long accessed by Indigenous and post-European societies, and hypothesize that under natural historical conditions (i.e., low human pressure) vegetation and aquatic ecosystems' responses to change are coupled through indirect climate influences—that is, past climate-driven vegetation changes dictated limnological trajectories. We used a multi-proxy paleoecological approach including drivers of terrestrial vegetation change (pollen), soil erosion (Titanium), human activity (agropastoralism indicators), and aquatic responses (diatoms) to estimate assemblage-wide rates of change and model their synchronous and asynchronous (lagged) relationships using Generalized Additive Models. Assemblage-wide rate of change results showed that between ca. 3000 and 400 calibrated years before present (cal years BP) terrestrial vegetation, agropastoralism and diatoms fluctuated along their mean regimes of rate of change without consistent periods of synchronous rapid change. In contrast, positive lagged relationships (i.e., asynchrony) between climate-driven terrestrial pollen changes and diatom responses (i.e., asynchrony) were in operation until ca. 750 cal years BP. Thereafter, positive lagged relationships between agropastoralism and diatom rates of changes dictated the lake trajectory, reflecting the primary control of human practices over the aquatic ecosystem prior European occupation. We interpret that shifts in Indigenous practices (e.g., valley terracing) curtailed nutrient inputs into the lake decoupling the links between climate-driven vegetation changes and the aquatic community. Our results demonstrate how rates of change of anthropogenic and climatic influences can guide dynamic ecological baselines for managing water ecosystem services in the Andes.

Assessment of the effectiveness of ultraviolet-C disinfection on transmission of hospital-acquired pathogens from prior room occupants.

To evaluate the effectiveness of ultraviolet-C (UV-C) disinfection as an adjunct to standard chlorine-based disinfectant terminal room cleaning in reducing transmission of hospital-acquired multidrug-resistant organisms (MDROs) from a prior room occupant. A retrospective cohort study was conducted to compare rates of MDRO transmission by UV-C status from January 1, 2016, through December 31, 2018. Acute-care, single-patient hospital rooms at 6 hospitals within an academic healthcare system in Pennsylvania. Transmission of hospital-acquired MDRO infection was assessed in patients subsequently assigned to a single-patient room of a source occupant with carriage of 1 or more MDROs on or during admission. Acquisition of 5 pathogens was compared between exposed patients in rooms with standard-of-care chlorine-based disinfectant terminal cleaning with or without adjunct UV-C disinfection. Logistic regression analysis was used to estimate the adjusted risk of pathogen transfer with adjunctive use of UV-C disinfection. In total, 33,771 exposed patient admissions were evaluated; the source occupants carried 46,688 unique pathogens. Prior to the 33,771 patient admissions, 5,802 rooms (17.2%) were treated with adjunct UV-C disinfection. After adjustment for covariates, exposed patients in rooms treated with adjunct UV-C were at comparable risk of transfer of any pathogen (odds ratio, 1.06; 95% CI, 0.84-1.32; P = .64). Our analysis does not support the use of UV-C in addition to post-discharge cleaning with chlorine-based disinfectant to lower the risk of prior room occupant pathogen transfer.