The Cambrian of Malaysia

The Cambrian of Malaysia is best represented by the quartzose Machinchang Formation in Langkawi, Kedah, northwest Peninsular Malaysia. It is divisible into three members. The oldest Hulor Member (>1260 m thick) is a coarsening upward succession of rhythmically interlayered graded siltstone, mudstone and clayey sandstone deposited as a prograded prodelta deposit. The middle Chinchin Member (>1575 m thick) is a fining upward succession of quartzose conglomerate and sandstone subdivisible into three beds. The lowest Anak Datai Bed (575 m thick) is made up of graded bedded, cross-bedded pebbly sandstone and conglomerate of estuarine channel-fills and thin to thick beds of low angle, planar cross-bedded sandstone with heavy mineral concentrations deposited as upper shoreface to beach deposits. The Temurun Bed (340 m thick) is of upper estuarine deposits of wavy-bedded sandstone and pebbly sandstone, fine tuffs and thin argillites. The upper Tengkorak Bed (>200 m thick) spans the Cambro-Ordovician boundary and consists of thick tabular bedded upper shoreface to beach fine sandstone with interbeds of fine rippled sandstone, acid tuff beds and mudstone belonging to a series of barrier beach complexes. The youngest Jemurok Member (>420 m thick) is a fining upward succession of siltstone, mudstone and hummocky cross-bedded sandstone and thin limestone deposited in storm influenced shoreface to back barrier lagoon with tidal channel environments. It has fragmentary trilobites, brachiopods, abundant trace fossils and the Kinneyian wrinkle marks.The overall sequence belongs to a highly destructive, wave-influenced delta deposit with a series of preserved beach-ridge complexes. Clastic sedimentation was reduced by peneplation of the source area as shown by the finer and thinner beds that grade into limestone of the overlying Ordovician Setul Formation.     

New marine mammal faunas (Cetacea and Sirenia) and sea level change in the Samlat Formation,Upper Eocene,near Ad-Dakhla in southwestern Morocco

The Samlat Formation is well exposed in coastal sections bordering the Atlantic Ocean south of Ad-Dakhla in southwestern Morocco. Here some 22 m of rhythmically-bedded, chert-rich, marine siltstones and marls are overlain by 1–1.5 m of vertebrate-bearing microconglomeratic sandstone, another 4–8 m of rhythmically-bedded siltstone and marl, and finally a second 3–6 m unit of vertebrate-bearing muddy sandstone. The microconglomeratic and muddy sandstones represent low sea stands in what is otherwise a deeper water sequence. Cetacean skeletons are rare but cetacean vertebrae are common in the lower sandstone (bed B1), where many show the effects of reworking. The cetaceans in bed B1represent a minimum of five species, from smallest to largest: cf. Saghacetus sp., cf. Stromerius sp., Dorudon atrox, cf. Dorudon sp., and Basilosaurus isis. Bed B1 yields rib fragments that may represent sirenians, but sirenians, if present, are rare. The only identifiable cetacean found in the upper sandstone (bed B2) is Basilosaurus sp. Dugongid sirenians identified as cf. Eosiren sp. are the most common mammal in bed B2. We interpret co-occurrence of the typically Early Priabonian species Dorudon atrox and Basilosaurus isis with smaller species more like Middle Priabonian genera Saghacetus osiris and Stromerius nidensis to indicate that bed B1 was deposited during low sea stand Pr-2 between the Early and Middle Priabonian (between the early and middle Late Eocene). Bed B2 is separated from B1 by an interval of deeper water sediment accumulation. Bed B2 could represent a later phase of Pr-2 or a subsequent Priabonian low sea stand (possibly Pr-3).     

Trends in Severity of Illness on ICU Admission and Mortality among the Elderly

Background

There is an increase in admission rate for elderly patients to the ICU. Mortality rates are lower when more liberal ICU admission threshold are compared to more restrictive threshold. We sought to describe the temporal trends in elderly admissions and outcomes in a tertiary hospital before and after the addition of an 8-bed medical ICU.

Methods

We conducted a retrospective analysis of a comprehensive longitudinal ICU database, from a large tertiary medical center, examining trends in patients’ characteristics, severity of illness, intensity of care and mortality rates over the years 2001–2008. The study population consisted of elderly patients and the primary endpoints were 28 day and one year mortality from ICU admission.

Results

Between the years 2001 and 2008, 7,265 elderly patients had 8,916 admissions to ICU. The rate of admission to the ICU increased by 5.6% per year. After an eight bed MICU was added, the severity of disease on ICU admission dropped significantly and crude mortality rates decreased thereafter. Adjusting for severity of disease on presentation, there was a decreased mortality at 28- days but no improvement in one- year survival rates for elderly patient admitted to the ICU over the years of observation. Hospital mortality rates have been unchanged from 2001 through 2008.

Conclusion

In a high capacity ICU bed hospital, there was a temporal decrease in severity of disease on ICU admission, more so after the addition of additional medical ICU beds. While crude mortality rates decreased over the study period, adjusted one-year survival in ICU survivors did not change with the addition of ICU beds. These findings suggest that outcome in critically ill elderly patients may not be influenced by ICU admission. Adding additional ICU beds to deal with the increasing age of the population may therefore not be effective.     

The Upper Cretaceous belemnite <Emphasis Type="Italic">Praeactinocamax plenus</Emphasis> (Blainville, 1827) from Lower Saxony (Upper Cenomanian,northwest Germany) and its distribution pattern in Europe

Occurrences of the Upper Cenomanian (Upper Cretaceous) belemnite Praeactinocamax plenus from the plenus Bed of northwest Germany (Söhlde-Loges working quarry near Salzgitter, Lower Saxony) are documented and described for the first time on the basis of two in situ finds. The find horizon and its surrounding beds are re-evaluated in a sequence stratigraphical context. In contrast to the interpretations of other authors, the plenus Bed is seen as a pelagization event in a parasequence of transgressively stacked beds, delimited by two significant erosion surfaces below and above. The exclusive occurrence of P. plenus in the top part of the plenus Bed and its absence from the post-plenus Bed succession, in the equivalent of which (higher part of the Plenus Marls Member) it is very common in southern England (Anglo-Paris Basin), is explained by ecological factors in stratigraphically complete sections (intra-shelf depressions) and by gaps in the stratigraphic records in swell settings. The distribution pattern of P. plenus suggests a preference for nearshore settings and a demersal mode of life.     

Bird-Like Anatomy,Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace

Background

Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb.

Methodology/Principal Findings

Here we describe a well-preserved theropod trackway in a Lower Jurassic (∼198 million-year-old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity.

Conclusions/Significance

The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.     

Martharaptor greenriverensis, a New Theropod Dinosaur from the Lower Cretaceous of Utah

Background

The Yellow Cat Member of the Cedar Mountain Formation (Early Cretaceous, Barremian?) of Utah has yielded a rich dinosaur fauna, including the basal therizinosauroid theropod Falcarius utahensis at its base. Recent excavation uncovered a new possible therizinosauroid taxon from a higher stratigraphic level in the Cedar Mountain Formation than F. utahensis.

Methodology/Principal Findings

Here we describe a fragmentary skeleton of the new theropod and perform a phylogenetic analysis to determine its phylogenetic position. The skeleton includes fragments of vertebrae, a scapula, forelimb and hindlimb bones, and an ischium. It also includes several well-preserved manual unguals. Manual and pedal morphology show that the specimen is distinct from other theropods from the Cedar Mountain Formation and from previously described therizinosauroids. It is here named as the holotype of a new genus and species, Martharaptor greenriverensis. Phylogenetic analysis places M. greenriverensis within Therizinosauroidea as the sister taxon to Alxasaurus + Therizinosauridae, although support for this placement is weak.

Conclusions/Significance

The new specimen adds to the known dinosaurian fauna of the Yellow Cat Member of the Cedar Mountain Formation. If the phylogenetic placement is correct, it also adds to the known diversity of Therizinosauroidea.     

Trace Fossils in Eolian Facies of the Upper Triassic-Lower Jurassic Dinosaur Canyon Member,Moenave Formation,Northern Arizona

The Dinosaur Canyon Member of the Moenave Formation, of Late Triassic to Early Jurassic (Rhaetian-Hettangian) age, consists predominantly of sandstones and mudstones deposited by sheet and channelized flow and by eolian processes. We document several previously undescribed biogenic structures in these strata. At one location, eolian dune sandstone hosts the lined, smooth-walled burrow Palaeophycus heberti (Saporta); these may be the nesting burrows of small sand wasps, or alternatively, the burrows of sand-treader camel crickets. Eolian dune facies that host abundant rhizoliths also are typically bioturbated. Circular markings that are convex in epirelief are assigned to Pustulichnus gregarious Ekdale and Picard. Unlined, non-ornamented burrows are unassigned. We speculate that both of these also were formed by the burrowing activity of one of the many species of sand wasp. Rhizoliths are particularly prominent at the tops of eolian dune sandstone beds and locally may host termite nests. Stabilization of the landscape by plants permitted pedogenic alteration of the sediments.     

The use of mosquito nets and the prevalence of Plasmodium falciparum infection in rural South Central Somalia

Background

There have been resurgent efforts in Africa to estimate the public health impact of malaria control interventions such as insecticide treated nets (ITNs) following substantial investments in scaling-up coverage in the last five years. Little is known, however, on the effectiveness of ITN in areas of Africa that support low transmission. This hinders the accurate estimation of impact of ITN use on disease burden and its cost-effectiveness in low transmission settings.

Methods and Principal Findings

Using a stratified two-stage cluster sample design, four cross-sectional studies were undertaken between March-June 2007 across three livelihood groups in an area of low intensity malaria transmission in South Central Somalia. Information on bed net use; age; and sex of all participants were recorded. A finger prick blood sample was taken from participants to examine for parasitaemia. Mantel-Haenzel methods were used to measure the effect of net use on parasitaemia adjusting for livelihood; age; and sex. A total of 10,587 individuals of all ages were seen of which 10,359 provided full information. Overall net use and parasite prevalence were 12.4% and 15.7% respectively. Age-specific protective effectiveness (PE) of bed net ranged from 39% among <5 years to 72% among 5–14 years old. Overall PE of bed nets was 54% (95% confidence interval 44%–63%) after adjusting for livelihood; sex; and age.

Conclusions and Significance

Bed nets confer high protection against parasite infection in South Central Somalia. In such areas where baseline transmission is low, however, the absolute reductions in parasitaemia due to wide-scale net use will be relatively small raising questions on the cost-effectiveness of covering millions of people living in such settings in Africa with nets. Further understanding of the progress of disease upon infection against the cost of averting its consequent burden in low transmission areas of Africa is therefore required.     

Alternating aeolian,sabkha and shallow-lake deposits from the Middle Triassic Gipsdalen Formation,Scoresby Land,East Greenland

Gypsum-bearing deposits of the Gipsdalen Formation (Anisian ? Ladinian ?) are described and interpreted on the basis of lithology, sedimentary structures and sequential pattern.The basal Kolledalen Member consists in the northwestern part of the area of coarse-grained alluvial-fan deposits overlain by cross-bedded aeolian sandstones and finer-grained sabkha or shallow desert-lake deposits. The overlying Kap Seaforth Member displays wel;-developed cyclic sedimentation. In the southeastern part of the area the ideal cycle consists of, from bottom to top: cross-bedded aeolian sandstone, structureless or wave-rippled sandstone of sabkha flat—marginal desert-lake origin, thin wave-rippled sandstone and irregularly bedded mudstone of marginal desert-lake origin and horizontally laminated mudstone deposited in an expanded desert lake.Foreset dips of the cross-bedded aeolian sandstones suggest alternating periods of north-northeast and south-southeast palaeowinds. It is concluded that the aeolian deposits of the Gipsdalen Formation were deposited at low palaeolatitudes in the northern hemisphere. In the Middle Triassic summer seasons the Intertropical Convergence Zone probably lay north of the Jameson Land Basin, which was reached by south-southeast trade winds. During the rest of the year the zone was situated to the south and the area came under the influence of north-northeast trade winds.     

Associations between Stroke Mortality and Weekend Working by Stroke Specialist Physicians and Registered Nurses: Prospective Multicentre Cohort Study

Background

Observational studies have reported higher mortality for patients admitted on weekends. It is not known whether this “weekend effect” is modified by clinical staffing levels on weekends. We aimed to test the hypotheses that rounds by stroke specialist physicians 7 d per week and the ratio of registered nurses to beds on weekends are associated with mortality after stroke.

Methods and Findings

We conducted a prospective cohort study of 103 stroke units (SUs) in England. Data of 56,666 patients with stroke admitted between 1 June 2011 and 1 December 2012 were extracted from a national register of stroke care in England. SU characteristics and staffing levels were derived from cross-sectional survey. Cox proportional hazards models were used to estimate hazard ratios (HRs) of 30-d post-admission mortality, adjusting for case mix, organisational, staffing, and care quality variables. After adjusting for confounders, there was no significant difference in mortality risk for patients admitted to a stroke service with stroke specialist physician rounds fewer than 7 d per week (adjusted HR [aHR] 1.04, 95% CI 0.91–1.18) compared to patients admitted to a service with rounds 7 d per week. There was a dose–response relationship between weekend nurse/bed ratios and mortality risk, with the highest risk of death observed in stroke services with the lowest nurse/bed ratios. In multivariable analysis, patients admitted on a weekend to a SU with 1.5 nurses/ten beds had an estimated adjusted 30-d mortality risk of 15.2% (aHR 1.18, 95% CI 1.07–1.29) compared to 11.2% for patients admitted to a unit with 3.0 nurses/ten beds (aHR 0.85, 95% CI 0.77–0.93), equivalent to one excess death per 25 admissions. The main limitation is the risk of confounding from unmeasured characteristics of stroke services.

Conclusions

Mortality outcomes after stroke are associated with the intensity of weekend staffing by registered nurses but not 7-d/wk ward rounds by stroke specialist physicians. The findings have implications for quality improvement and resource allocation in stroke care. Please see later in the article for the Editors'' Summary     

Genome Analysis of Legionella pneumophila Strains Using a Mixed-Genome Microarray

Background

Legionella, the causative agent for Legionnaires’ disease, is ubiquitous in both natural and man-made aquatic environments. The distribution of Legionella genotypes within clinical strains is significantly different from that found in environmental strains. Developing novel genotypic methods that offer the ability to distinguish clinical from environmental strains could help to focus on more relevant (virulent) Legionella species in control efforts. Mixed-genome microarray data can be used to perform a comparative-genome analysis of strain collections, and advanced statistical approaches, such as the Random Forest algorithm are available to process these data.

Methods

Microarray analysis was performed on a collection of 222 Legionella pneumophila strains, which included patient-derived strains from notified cases in the Netherlands in the period 2002–2006 and the environmental strains that were collected during the source investigation for those patients within the Dutch National Legionella Outbreak Detection Programme. The Random Forest algorithm combined with a logistic regression model was used to select predictive markers and to construct a predictive model that could discriminate between strains from different origin: clinical or environmental.

Results

Four genetic markers were selected that correctly predicted 96% of the clinical strains and 66% of the environmental strains collected within the Dutch National Legionella Outbreak Detection Programme.

Conclusions

The Random Forest algorithm is well suited for the development of prediction models that use mixed-genome microarray data to discriminate between Legionella strains from different origin. The identification of these predictive genetic markers could offer the possibility to identify virulence factors within the Legionella genome, which in the future may be implemented in the daily practice of controlling Legionella in the public health environment.     

Most Personal Exposure to House Dust Mite Aeroallergen Occurs during the Day

Background

The bed is commonly regarded as the main site of house dust mite exposure; however this has not been directly established by continuous measurements. The objective of this study was to determine the pattern of personal exposure to mite aeroallergen over 24 hours.

Methods

12 adults each collected 9 sequential samples (8 during the day, mean 115 mins, and one overnight, mean 514 mins) over 24 hours using a portable air-pump (2L/min) connected to an IOM filter located on the shoulder during the day and on the bed head overnight. Samples were analysed for mite allergen Der p 1 by ELISA. Location and activity were recorded. A mixed model analysis was performed to determine exposure as a function of 14 categories of activity.

Results

Personal aeroallergen exposure differed widely over time, both within and between subjects. The highest average exposure (1117 pg/m³, 95% CI: 289-4314) occurred on public transport and the lowest overnight in bed (45 pg/m³, 95% CI: 17-17), which contributed only 9.8% (95% CI: 4.4%-15.1%) of total daily exposure. Aeroallergens were not related to bed reservoirs.

Conclusion

The study challenges the current paradigm that the bed is the main site of HDM exposure and instead suggests most exposure occurs in association with domestic activity and proximity to other people. Effective mite interventions, designed to improve asthma outcomes, need to first identify and then address the multiple sources of aeroallergen exposure.     

Worm grunting, fiddling, and charming--humans unknowingly mimic a predator to harvest bait

Background

For generations many families in and around Florida''s Apalachicola National Forest have supported themselves by collecting the large endemic earthworms (Diplocardia mississippiensis). This is accomplished by vibrating a wooden stake driven into the soil, a practice called “worm grunting”. In response to the vibrations, worms emerge to the surface where thousands can be gathered in a few hours. Why do these earthworms suddenly exit their burrows in response to vibrations, exposing themselves to predation?

Principal Findings

Here it is shown that a population of eastern American moles (Scalopus aquaticus) inhabits the area where worms are collected and that earthworms have a pronounced escape response from moles consisting of rapidly exiting their burrows to flee across the soil surface. Recordings of vibrations generated by bait collectors and moles suggest that “worm grunters” unknowingly mimic digging moles. An alternative possibility, that worms interpret vibrations as rain and surface to avoid drowning is not supported.

Conclusions

Previous investigations have revealed that both wood turtles and herring gulls vibrate the ground to elicit earthworm escapes, indicating that a range of predators may exploit the predator-prey relationship between earthworms and moles. In addition to revealing a novel escape response that may be widespread among soil fauna, the results show that humans have played the role of “rare predators” in exploiting the consequences of a sensory arms race.     

Comparison of ARIMA and Random Forest time series models for prediction of avian influenza H5N1 outbreaks

Background

Time series models can play an important role in disease prediction. Incidence data can be used to predict the future occurrence of disease events. Developments in modeling approaches provide an opportunity to compare different time series models for predictive power.

Results

We applied ARIMA and Random Forest time series models to incidence data of outbreaks of highly pathogenic avian influenza (H5N1) in Egypt, available through the online EMPRES-I system. We found that the Random Forest model outperformed the ARIMA model in predictive ability. Furthermore, we found that the Random Forest model is effective for predicting outbreaks of H5N1 in Egypt.

Conclusions

Random Forest time series modeling provides enhanced predictive ability over existing time series models for the prediction of infectious disease outbreaks. This result, along with those showing the concordance between bird and human outbreaks (Rabinowitz et al. 2012), provides a new approach to predicting these dangerous outbreaks in bird populations based on existing, freely available data. Our analysis uncovers the time-series structure of outbreak severity for highly pathogenic avain influenza (H5N1) in Egypt.     

Geology of the Early Arikareean Sharps Formation on the Pine Ridge Indian Reservation and Surrounding Areas of South Dakota and Nebraska

Based on geologic mapping, measured sections, and lithologic correlations, the local features of the upper and lower type areas of the Early Arikareean (30.8–20.6 million years ago) Sharps Formation are revised and correlated. The Sharps Formation above the basal Rockyford Member is divided into two members of distinct lithotypes. The upper 233 feet of massive siltstones and sandy siltstones is named the Gooseneck Road Member. The middle member, 161 feet of eolian volcaniclastic siltstones with fluvially reworked volcaniclastic lenses and sandy siltstone sheets, is named the Wolff Camp Member. An ashey zone at the base of the Sharps Formation is described and defined as the Rockyford Ash Zone (RAZ) in the same stratigraphic position as the Nonpareil Ash Zone (NPAZ) in Nebraska. Widespread marker beds of fresh water limestones at 130 feet above the base of the Sharps Formation and a widespread reddish-brown clayey siltstone at 165 feet above the base of the Sharps Formation are described. The Brown Siltstone Beds of Nebraska are shown to be a southern correlative of the Wolff Camp Member and the Rockyford Member of the Sharps Formation. Early attempts to correlate strata in the Great Plains were slow in developing. Recognition of the implications of the paleomagnetic and lithologic correlations of this paper will provide an added datum assisting researchers in future biostratigraphic studies. Based on similar lithologies, the Sharps Formation, currently assigned to the Arikaree Group, should be reassigned to the White River Group.     

Fragmentation Impairs the Microclimate Buffering Effect of Tropical Forests

Background

Tropical forest species are among the most sensitive to changing climatic conditions, and the forest they inhabit helps to buffer their microclimate from the variable climatic conditions outside the forest. However, habitat fragmentation and edge effects exposes vegetation to outside microclimatic conditions, thereby reducing the ability of the forest to buffer climatic variation. In this paper, we ask what proportion of forest in a fragmented ecosystem is impacted by altered microclimate conditions driven by edge effects, and extrapolate these results to the whole Atlantic Forest biome, one of the most disturbed biodiversity hotspots. To address these questions, we collected above and below ground temperature for a full year using temperature sensors placed in forest fragments of different sizes, and at different distances from the forest edge.

Principal Findings

In the Atlantic forests of Brazil, we found that the buffering effect of forests reduced maximum outside temperatures by one third or more at ground level within a forest, with the buffering effect being stronger below-ground than one metre above-ground. The temperature buffering effect of forests was, however, reduced near forest edges with the edge effect extending up to 20 m inside the forest. The heavily fragmented nature of the Brazilian Atlantic forest means that 12% of the remaining biome experiences altered microclimate conditions.

Conclusions

Our results add further information about the extent of edge effects in the Atlantic Forest, and we suggest that maintaining a low perimeter-to-area ratio may be a judicious method for minimizing the amount of forest area that experiences altered microclimatic conditions in this ecosystem.     

The Downton Series as the fourth Series of the Silurian System

A review of lithofacies and fossil distributions in the Downton strata of the Welsh Borderland and Wales indicates that these beds form a suitable basis for definition of a chronostratigraphical division of Series rank within the Silurian System. The basal boundary stratotype for the Downton Series is defined at the base of the Ludlow Bone Bed Member of the Downton Castle Sandstone Formation in a section at Whitcliffe Road, Ludlow. Shallow water marine sediments span the boundary, with no evidence of a measurable time break. Correlation of the base of the Downton Series from eastern North America through Baltoscandia and Poland suggests that it lies at or very close to the base of the Monograptus ultimus Biozone and thus approximates to the base of the Přiacute;dolí beds of Bohemia. This paper formed a submission to the Subcommission on Silurian Stratigraphy in May. 1981. □ Silurian, Downtown Series, standard subdivision, lithostratigraphy, biostratigraphy, chronostratigraphy, correlation.