Nevada USA Research Articles

Understanding sexual violence in sex working populations-Law, legal consciousness and legal practice in four countries (2021-2023): Study Protocol v2.5.

Globally, the most important human rights and public health issue that sex workers face is their experience of high levels of violence (Kinnell, 2006, Kinnell, 2008, Alexander, 1999). Deering's systematic review estimated levels of sexual violence in sex working populations as being between 14% and 54% (Deering et al, 2014). This international, robust mixed methods study will explore the frequency of sexual violence against sex workers, barriers in criminal justice and the legal consciousness of sex workers regarding their rights and consent. The hypothesis to be tested is that the safety of sex workers from sexual violence is mediated by the differing legal contexts of sex work environments. We will compare experiences across research sites in the context of legalisation (Nevada USA), client criminalisation (Northern Ireland), decriminalisation (New Zealand) and partial criminalisation (England, Scotland and Wales) [henceforth ESW]. An international survey (n = 1,000) will be translated into several languages, to disaggregate experiences by demographic categories (gender, ethnicity, sexual orientation) and sex work sector (including online, street-based and brothels). Interviews (n = 100) with sex workers, police, prosecutors and service providers will be thematically analysed to explore legal consciousness, why the patterns occur and contextualise the statistical findings. These data will be supplemented with comparative legislative, policy and case analysis. Research study data will be used to compare the social factors and legal norms shaping sex workers experiences of sexual violence, justice and support interventions. Recommendations for a 'best practice' review of legal improvements and support interventions will be produced following completion of the study. Given the sensitive nature of the research, robust ethical and data protection mechanisms are in place. The research has ethical approval from each research site, an Advisory Board and trained, paid peer researchers to assist with data gathering, analysis and dissemination. The study will report findings in 2023/2024.

Mafic intrusions record mantle inputs and crustal thickness in the eastern Sierra Nevada batholith, California, USA

Contributions of heat and/or mass from mafic magmas are commonly invoked in models of voluminous granodiorite and andesite generation in magmatic and volcanic arcs worldwide. However, mafic intrusions are a volumetrically minor component in most arc batholiths. This is the case in the Sierra Nevada batholith, California, USA, where gabbro and diorite plutons are smaller and less abundant than the granitoid suites that make up the bulk of the batholith. Here, we constrain the timing and geochemistry of mafic intrusions in the Sierra Nevada batholith to assess the role of these compositions in arc batholith construction. Previous detailed studies on a limited number of mafic intrusions demonstrate that they formed penecontemporaneously with the felsic batholith, but there is a need for a broader survey of mafic plutons using modern geochronological techniques. New U-Pb zircon ages for 13 gabbro to diorite plutons and geochemistry from 17 mafic intrusions in the eastern Sierra Nevada batholith document two main episodes of mafic magmatism in the eastern Sierra Nevada batholith, from 168 Ma to 145 Ma and from 100 Ma to 89 Ma. These episodes overlap with the ages of granitoid plutons in the eastern Sierra Nevada batholith, including the Late Jurassic Palisade Crest and Late Cretaceous John Muir intrusive suites, in addition to other felsic plutons dated in the eastern Sierra Nevada batholith. Non-primitive mineral compositions in the mafic bodies indicate that their parental magmas are the evolved products of mantle-derived basalts that first differentiated in the lower crust prior to ascent and crystallization in the upper crust. The presence of rocks with cumulate textures, as well as a wide range of bulk-rock compositions (SiO2 wt% 38−64, Mg# 39−74), show that magmatic differentiation continued within each mafic body after intrusion into the upper crust. Sr/Y ratios in melt-like (i.e., non-cumulate) mafic samples suggest that the crustal thickness of the Sierra Nevada batholith was roughly 30 km in the Early Jurassic and increased to ∼44 km by the Late Cretaceous. Concomitant intrusion of mafic melts along with voluminous granitoid plutons supports mantle melting as a major contributor of heat and magmatic volumes to the crust during construction of the eastern Sierra Nevada batholith.

Displacement Analysis of Geothermal Field Based on PSInSAR And SOM Clustering Algorithms A Case Study of Brady Field, Nevada—USA

The availability of free and high temporal resolution satellite data and advanced SAR techniques allows us to analyze ground displacement cost-effectively. Our aim was to properly define subsidence and uplift areas to delineate a geothermal field and perform time-series analysis to identify temporal trends. A Persistent Scatterer Interferometry (PSI) algorithm was used to estimate vertical displacement in the Brady geothermal field located in Nevada by analyzing 70 Sentinel-1A Synthetic-Aperture Radar (SAR) images, between January 2017 and December 2019. To classify zones affected by displacement, an unsupervised Self-Organizing Map (SOM) algorithm was applied to classify points based on their behavior in time, and those clusters were used to determine subsidence, uplift, and stable regions automatically. Finally, time-series analysis was applied to the clustered data to understand the inflection dates. The maximum subsidence is –19 mm/yr with an average value of –6 mm/yr within the geothermal field. The maximum uplift is 14 mm/yr with an average value of 4 mm/yr within the geothermal field. The uplift occurred on the NE of the field, where the injection wells are located. On the other hand, subsidence is concentrated on the SW of the field where the production wells are located. The coupling of the PSInSAR and the SOM algorithms was shown to be effective in analyzing the direction and pattern of the displacements observed in the field.

Temperature, fluid content and rheology of localized ductile shear zones in subsolidus cooling plutons

AbstractTemperature and fluid content are critical parameters that control rock rheology and strain localization in the continental crust. Here, we determine by thermodynamic modelling the of localized ductile shearing during cooling of three different granitoid plutons: the Rieserferner and the Adamello plutons in the Italian Alps, and the Lake Edison pluton in the Sierra Nevada—USA. Shear zones exploited precursor joints, associated veins and alteration zones. and P−T phase diagram sections were computed with Perple_X in the system MnO−Na2O−CaO −K2O−FeO−MgO−Al2O3−SiO2−H2O−Fe2O3. The phase diagram sections show that the nucleation of the brittle precursors (joints, veins) occurred at T» 450°C at fluid‐saturated conditions. Localized ductile shearing likely occurred at temperature ranging between 420 and 460°C evolving from initially fluid‐saturated to fluid‐undersaturated conditions in a closed system. In this temperature range, granitoid rocks are potentially subject to a series of retrograde metamorphic reactions replacing the load‐bearing feldspars with weaker phyllosilicates. Metamorphic reactions occurred in spatial association with the precursory structures, leading to localized shearing. Decreasing temperature and fluid‐undersaturated conditions likely hampered progressive strain accommodation in shear zones by slowing down metamorphic reactions, thermally activated dislocation creep processes, fluid‐mediated deformation mechanisms and weakening mechanisms. Polyphase granitoid ultramylonite and mylonitic quartz veins have been affected differently by the fluid‐undersaturated conditions of the system, as consequence of different dominant deformation mechanisms and syn‐kinematic paragenesis during localized shearing. Localized ductile shearing in cooling plutons effectively occurs in a limited temperature range (420–460°C) in which the strain accommodation capacity of the shear zone is controlled by the negative feedback between the cooling rate, the kinetics of metamorphic reactions and deformation mechanisms, and the consumption of the limited amount of available fluids.

Using machine learning for real-time estimates of snow water equivalent in the watersheds of Afghanistan

Abstract. In the mountains, snowmelt often provides most of the runoff. Operational estimates use imagery from optical and passive microwave sensors, but each has its limitations. An accurate approach, which we validate in Afghanistan and the Sierra Nevada USA, reconstructs spatially distributed snow water equivalent (SWE) by calculating snowmelt backward from a remotely sensed date of disappearance. However, reconstructed SWE estimates are available only retrospectively; they do not provide a forecast. To estimate SWE throughout the snowmelt season, we consider physiographic and remotely sensed information as predictors and reconstructed SWE as the target. The period of analysis matches the AMSR-E radiometer's lifetime from 2003 to 2011, for the months of April through June. The spatial resolution of the predictions is 3.125 km, to match the resolution of a microwave brightness temperature product. Two machine learning techniques – bagged regression trees and feed-forward neural networks – produced similar mean results, with 0–14 % bias and 46–48 mm RMSE on average. Nash–Sutcliffe efficiencies averaged 0.68 for all years. Daily SWE climatology and fractional snow-covered area are the most important predictors. We conclude that these methods can accurately estimate SWE during the snow season in remote mountains, and thereby provide an independent estimate to forecast runoff and validate other methods to assess the snow resource.

Initial Transient Phenomena Impact on Plasma CVD of Ultrathin Silicon Nitride and Silicon Carbon Nitride Dielectrics for Nano Devices Cu-Low k Interconnects

The initial transient (ITS) phenomena in plasma enhanced Chemical Vapor Deposition (PECVD) process was identified in early 1980’s (1). This ITS phenomenon has impact on the bonding structure and composition of plasma deposited silicon nitride (1) and amorphous silicon (2) films at the initial film-substrate interface. When the deposited film is in micron thickness, the ITS impact is generally smaller. The shrinking of semiconductor devices and the corresponding push to increase device density is continuing in the quest for improved performance of integrated circuits. Nano scale thickness low temperature plasma CVD dielectric films such as silicon nitride and silicon carbon nitride used as cap materials (3) for Cu interconnects that are expected to reach to sub-10 nm dimension next few years. The compositional variation in PECVD films at the interface by ITS which had a relatively small impact in past semiconductor technologies is becoming a significant factor in film’s properties as we scale film thickness down to sub-10nm. In this paper, we will present in detail the impact of the initial transient plasma in CVD process on the ultrathin nano thick cap and-low k dielectric films that are being used for advanced device interconnect fabrication, We will show that we can modify the current standard PECVD process to alleviate the impact of ITS phenomena. Some ITS impact on nano thick film are: a) PECVD silicon nitride / silicon carbon nitride dielectric cap films are normally deposited with a mixture of silane/ammonia or other carbosilane/ammonia precursors. The initial breakdown of silane is strongly affected by the plasma conditions and the dissociation thermodynamic of the precursors. Deposition rates can be different on Cu versus dielectric surfaces due differences in charging effects (see Figure 1). Additionally, the silane molecule is relatively unstable and more reactive as compared to ammonia, and typically dissociate rapidly first to form more conformal SiHx deposition radicals before the plasma reaches a steady state. Subsequently, PECVD with SiH4/NH3 precursors will normally produce a Si-rich silicon nitride composition at the interface. Silicon carbon nitride films can be deposited from more stable carbosilane precursors. In this case, the thickness of the Si-rich interface zone can be reduced, and a C-rich film surface may be deposited under specific deposition condition. This modulation may be exploited to control electrical (k, breakdown/leakage) and adhesion properties of the film for Cu low k interconnect structures. For a very thin dielectric cap deposited on a patterned structure of Cu and ultra-low k dielectric, the film thickness deposited on Cu versus the dielectric surface will be slightly different due to the differential local plasma charging effect during initial transient deposition period as shown in fig 1. This deposition rate difference will impact the film’s barrier and electrical properties, gap fill performance and subsequent in Cu-low k fabrication. In this case, plasma ITS charging is the principle mechanism that cause differences in film’s thickness. b) For typical PECVD SiN deposition process, the initial dissociation of SiH4 and/or NH3 will create reactive species that subsequently etch the deposited ultra-low k pSiCOH dielectric surface. These reactive species can produce substantial damage to pSiCOH, increase dielectric constant and subsequently poor reliability in final electronic devices. This damage can be reduced significantly by using an initially low rf plasma power and then increasing to a higher rf plasma power for the remainder of the deposition (4). ITS negative impact to devices and mitigation method will be discussed. c) For ultrathin cap films for Cu interconnects, such as SiN, variations in film composition at the interface will cause significant variation in electrical properties and conformality. To mitigate the ITS effect, a cyclic, multi-step deposition process utilizing plasma surface treatment was developed. A multilayers film with better conformality and consistent film’s properties was achieved. Using this novel cyclic process, high quality dielectrics SiN and SiNO at sub-10 nm thickness can be deposited consistently and reproducibly for Cu-low k interconnect fabrication as showed in Figure 2. In summary, the ITS phenomena on plasma CVD, its impact in nano thick film fabrication and methods to mitigate the ITS’s negative impact will be presented in the paper.

The Basin and Range Dixie Valley Geothermal Wellfield, Nevada, USA—A test bed for developing an Enhanced Geothermal System exploration favorability methodology

The Dixie Valley Geothermal Wellfield (DVGW), a Basin and Range type system in central Nevada USA, is used as an exploration case history for Enhanced Geothermal Systems (EGS). It encompasses an area of approximately 170km2. The wellfield produces 67MW of geothermal power and it contains a number of high temperature non-productive wells. This wellfield was chosen as the calibration site for the development of an EGS exploration methodology due to its extensive body of geoscience data and information on the geothermal system and most importantly, well results in the public domain. This existing body of data (ca. 2011) was in part re-interpreted to produce a baseline conceptual model in terms of a number of serial cross-sections for the available data sets: geology, seismic reflection, resistivity, temperature, gravity-magnetic, and p-wave velocity (Vp). The exploration methodology was calibrated against available geothermal well results. Based on a comprehensive review of all available geoscience and well data, EGS favorability maps were generated, from +1km above sea level (asl) to −4km asl at 0.5km intervals, for the three key EGS parameters of interest: rock type, temperature, and stress. Complimentary trust (“confidence-in-the-data-used”) maps were also created at the same scale to, among other things, indicate where additional data may be required.Quantitative geostatistical analysis of the geoscience data was conducted, among other factors, to address the question of whether the baseline geoscience data could be used to predict EGS favorability without the advantage of existing well temperature data. Classification and Regression Tree (CART) was one of a number of geostatistical methods applied to the baseline geoscience data and it provided the most promising results. In CART, the response variable (RV) is predicted while using explanatory variables (EVs). The geoscience parameters (EVs) considered in the CART analysis included temperature, Vp, resistivity from magnetotellurics, Coulomb Stress Change (CSC), dilatational strain (from CSC modeling), vertical stress, lithology based on geologic analysis, lithology based on gravity–magnetic modeling (G–M lithology) and the presence or absence of a fault. Temperature increases with depth in the DVGW. Vertical stress also increases with depth and it was deemed as a redundant EV. As such, a CART sensitivity analysis was applied to the baseline data set with and without vertical stress being considered as an EV to determine the effect of removing vertical stress and to evaluate with subsets of EVs that could be predictive of key EGS parameters. R2-values ranging from 0.611 to 0.841 were obtained for the RVs: temperature, lithology, productive vs. non-productive hydrothermal cells and expected EGS favorable cells (the response variables) using both cross-section and well data and not considering vertical stress. However, these CART results were not used in the generation of the favorability maps because this is the first analysis of its kind that the authors are aware of and more testing at other sites needs to be done; the raw total baseline data set described above was considered the most appropriate for this study.

Application of seismic attributes for constraining Magnetotelluric Inversion

SUMMARY Unconstrained inversion of surface magnetotelluric data generates non-uniqueness solutions. Boundaries derived from seismic reflectively images have the potential to substantially improve MT inversion. Seismic should be highly beneficial where significant and strong reflectors can reasonably be associated with contrast in electrical conductivity across well-defined relatively continuous boundaries. We show how seismic reflections can assist in defining such inversion controls as the smoothness penalty across known boundaries. We apply and compare a range of cooperative inversion strategies using large scale co-located magnetotelluric and seismic reflection field data sets from the Carlin style gold district in Nevada USA.

Origin and evolution of palaeokarst within the Lower Ordovician (Ibexian) Goodwin Formation (Pogonip Group)

AbstractPalaeokarst within the Lower to Middle Ordovician Goodwin Formation, Pogonip Group (upper Ibexian-lower Whiterockian) was examined in detail at Meiklejohn Peak, Nevada USA in order to determine its origin, evolution, and relationship to sea level change. Detailed outcrop and petrographic examination of dolostone breccias and host rock reveals that palaeokarst was formed and affected by two distinct cycles of sea level change. A relative transgression resulted in deposition of lagoonal, ooid shoal, and shallow subtidal facies as sea level rose. Exposure of the carbonate platform led to the formation of multiple phreatic caves below the water table, as well as the development of numerous vadose conduits from the downward percolation of meteoric waters. Vadose water flow through early cave-wall and cave-roof collapse breccias resulted in rounding of smaller breccias clasts via physical transport and corrosion, while subsidence of subsurface karst led to the formation of a palaeodoline at the exposure surface. A second relative transgression deposited lagoonal sediments over the older karst; subsequent re-exposure of the carbonate platform resulted in the development of small breccia pockets as well as grikes within the youngest lagoonal sediments, and may have led to further corrosion of the older, deeper subsurface karst. The distal location of the study area within the carbonate platform suggests karst formation was the result of a substantial drop in relative sea level; the presence of multiple generations of palaeokarst imply that at least two higher-frequency cycles of sea-level change overprint the larger regression.

Zn-rich smectite from the Silver Coin Mine, Nevada, USA

AbstractMore than 100 minerals have been reported from the Silver Coin Mine, Nevada USA; five new minerals have been discovered here, due to the unusual geochemical environment. The present study reports on the investigation of a greenish clayey sample from the Silver Coin Mine. After the separation of a fine fraction to enrich the clay minerals, sauconite, a rare Zn-rich smectite, was found by X-ray diffraction (XRD) and was further characterized by differential thermal analysis (DTA), infrared (IR) spectroscopy and scanning electron microscopy (SEM). The Zn-rich smectite is accompanied by illite, minor kaolinite/halloysite and traces of gibbsite (as was indicated by the IR spectroscopy). The occurrence indicates an acidic environment probably caused by oxidation of sulfides.The determination of the structural formula, to further characterize the Zn-rich smectite, was difficult because of the multi-clay mineral assembly. However, different SEM-EDX (energy dispersive X-ray) approaches as well as transmission electron microscopy (TEM)-EDX analysis helped to characterize the smectite as Al-rich sauconite with some exchangeable K+.

Soil microbial responses to nitrogen addition in arid ecosystems

The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH, and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts). We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO3-NH4 mix at 0, 7, and 15 kg N ha-1 y-1 from March 2012 to March 2013. In March 2013, biocrust (0–0.5 cm) and bulk soils (0–10 cm) were collected beneath Ambrosia canopies and in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities and rates of N transformation. By most measures, nutrient availability, microbial biomass, and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N amendment that included data from 14 other studies. Effect sizes were calculated for biomass and metabolic responses. Regressions of effect sizes, calculated for biomass, and metabolic responses, showed similar trends in relation to N application rate and N load (rate × duration). The critical points separating positive from negative treatment effects were 88 kg ha-1 y-1 and 159 kg ha-1, respectively, for biomass, and 70 kg ha-1 y-1 and 114 kg ha-1, respectively, for metabolism. These critical values are comparable to those for microbial biomass, decomposition rates and respiration reported in broader meta-analyses of N amendment effects in mesic ecosystems. However, large effect sizes at low N addition rates indicate that arid ecosystems are sensitive to modest increments in anthropogenic N deposition.

Corrigendum to “Arsenic concentrations in dust emissions from wind erosion and off-road vehicles in the Nellis Dunes Recreational Area, Nevada USA” [Aeolian Res. 5 (2012) 77–89

Corrigendum to “Arsenic concentrations in dust emissions from wind erosion and off-road vehicles in the Nellis Dunes Recreational Area, Nevada USA” [Aeolian Res. 5 (2012) 77–89

Micromorphological investigation of pedogenic barite in Mormon Mesa petrocalcic horizons, Nevada USA: Implication for genesis

Barite crystals are identified in stage VI petrocalcic horizons at Mormon Mesa, Nevada. Their presence is significant because barite is not typically associated with arid soil processes. Barite is identified through backscatter SEM/EDS as bright white crystals with EDS peaks of high Ba, S, and O. Barite crystals are euhedral, tabular to acicular crystals ranging in size from 1 to 50μm in length and 1–20μm in diameter, and as small (2–4μm) tabular-ovoid crystals. Forty-one percent of the barite in SEM images is associated with fibers of palygorskite and/or sepiolite. Barite crystals are also associated with linear voids, circular pores, and within micropores between fibers of silicate clays. The formation of barite at Mormon Mesa is attributed to: (i) The dissolution of Ba and SO4 ions from detrital minerals and dust that are flushed into the soil profile and precipitate as barite; and/or (ii) Biomineralization of barite in micro-environments suitable for bacteria or other organisms within the petrocalcic horizon.

Discriminating between background and mine-impacted groundwater at the Phoenix mine, Nevada USA

Abstract Differentiating between mineralized and non-mineralized background groundwater chemistry at a mine site can be challenging if there is an overprint of past and/or current mining on naturally mineralized conditions. At the Phoenix mine in the Copper Canyon mining district of Nevada, quantile–quantile H+/SO4 plots were used to segregate four wells clearly impacted by historical mining activity. The mineralogy of rock at the elevation of the well screen interval was used to partition the 53 remaining wells into mineralized and non-mineralized populations. For each class, groundwater chemistry was examined to identify if SO4 and H+ trends were stable (unimpacted) or increasing (impacted). Then each well was mapped as one of four resulting groundwater types across the mine site, defining the spatial extent of the different groups. Several groundwater regions were identified. A group of mineralized, mine-impacted wells (Type II) are located in Philadelphia Canyon adjacent to the Cu leach facility, with the anthropogenically impacted area bounded by several hydrologically downgradient, mineralized, unimpacted wells (Type I) to the south and east. There is a set of non-mineralized, impacted wells (Type III) downgradient from the tailings pond facility, where a historical release of SO4 is apparent in the well record. However, in some downgradient wells the tailings pond pump-back mitigation system has resulted in recovery of the groundwater quality to a non-mineralized background condition. Finally, in the vicinity of the Reona heap leach pad, there is a group of non-mineralized, unimpacted wells (Type IV). Not surprisingly, most mineralized wells (Types I and II) are located in or near mined areas, while non-mineralized wells (Types III and IV) tend to be in the southern portion of the facility in the alluvia of Buffalo and Reese River valleys. Once the well population was categorized, Phx-F was identified with extremely mineralized background groundwater (pH = 3.8; SO4 = 4600 mg/L; As = 0.056 mg/L; Cu = 72 mg/L; Zn = 61 mg/L), which required further analysis. The elevation of the Phx-F screen interval had up to 5% jarosite, with mineralized fracture zones mapping directly to cavities in the adjacent Iron Canyon mine that originally contained a saturated ferrous sulfate solution, explaining the anomalous chemistry in this well. This study demonstrates that an empirical approach using mining history, deposit geology, hydrogeology, well screen elevation mineralogy, groundwater chemistry trends, statistical analysis, and geochemical modeling provides a technique to distinguish among different classes of groundwater at the operating Phoenix mine site. Such an approach (or a derivative) may prove useful at other mines with different mineralogies and hydrogeologic settings.

An Unusual Fetal Ductus Arteriosus Pathway

Received January 22, 2008, from the Children’s Heart Center, Las Vegas, Nevada USA (R.J.A., W.N.E., W.C., R.R.); Division of Cardiology, Department of Pediatrics (R.J.A., W.N.E., W.C., R.R.), and MaternalFetal Medicine Program, Department of Obstetrics and Gynecology (D.R.), University of Nevada School of Medicine, Las Vegas, Nevada USA; Department of Obstetrics and Gynecology, University Medical Center, Las Vegas, Nevada USA (D.R.); and Nevada Perinatal, Las Vegas, Nevada USA (J.M.). Manuscript accepted for publication February 12, 2008. Address correspondence to Ruben J. Acherman, MD, Children’s Heart Center, 3006 S Maryland Pkwy, Suite 690, Las Vegas, NV 89109 USA. E-mail: IAcherman@aol.com uctal tortuosity occurs normally with advancing gestational age.1 Early in gestation, the 2-dimensional echocardiographic high transverse thoracic view shows the ductus arteriosus as a straight channel from the main pulmonary artery to the descending aorta. As gestation progresses, the ductus normally curves to the left away from the aortic arch. We report a fetus that had unusual ductal tortuosity: curving to the right posterior to the ascending aorta and above the right pulmonary artery. We were asked to evaluate this fetus because obstetric sonography suggested a ductus arteriosus abnormality. Initial fetal echocardiography performed at 32 weeks’ gestation showed an unusual ductus arteriosus pathway turning toward the right behind the ascending aorta and above the right pulmonary artery (Figures 1–3). There was no evidence of ductal constriction on follow-up fetal echocardiograms. A healthy neonate was delivered at term. The postnatal echocardiogram showed a ductal anatomy similar to the prenatal findings. Additionally, the ductus arteriosus was aneurysmatic at its aortic end and constricted at its midportion. At 3 days of age, echocardiographic findings were normal without evidence of ductal flow. In summary, we report a previously undescribed fetal ductus arteriosus pathway in a patient that had no evidence of a prenatal or postnatal hemodynamic disturbance.

A restudy of Oryctocephalus indicus (Reed, 1910)

Abstract Restudy on morphology of Oryctocephalus indicus (Reed, 1910), based on suecimens from Guizhou, China and Nevada USA, suggests that the subspecies regarded previously as Oryctocephalus indicus indicus (Reed, 1910), O. indicus latus Zhoa et Yuan 2002, and O. indicus kobayashi Saito, 1934, are synonymous, and Oryctocephalus americanus Sundberg et Mc Collum, 2003 is a similar form of O. indicus. Oryctocephalus indicus is rediagnosed as having a glabella that is subconical in outline and tapering forward slightly; a thorax that comprises 12 segments, and a small pygidium that bears 2–3 axial rings with a terminal piece and a postaxial ridge. Oryctocephalus indicus is widely distributed in eastern Guizhou and ranges through a great interval of Kaili Formation. Its first appearance is almost identical with these events of trilobite extinction-recovery occurring at the end of Early Cambrian, the alternation of acritach assemblages, the change of trace elements (RFE) and stable isotopes (carbon) at the Wu...

From the chair

It was great fun seeing everyone at the "Fourth Annual ACM-SIGMIS Reception," held as an ACM-SIGMIS event on Saturday, December 11, 2004, prior to the International Conference on Information Systems (ICIS2004) in Washington, D.C. USA. Thanks to all of our members and their guests who attended. Photos from the event are posted on ACM-SIGMIS's website at: http://www.acm.org/sigmis. Mark your calendar now for next year's reception, scheduled for Saturday, December 10, 2005, from 5:30-7:00pm, prior to ICIS2005 to be held in Las Vegas, Nevada USA, December 11--14, 2005.Please plan to attend our 2005 ACM-SIGMIS Computer Personnel Research (CPR2005) Conference. For more information, please contact the Conference Chair, Mike Gallivan, Georgia State University, mgallivan@gsu.edu, the Program Co-Chairs, Jo Ellen Moore, joemoor@siue.edu and Susan E. Yager, syager@siue.edu, both of Southern Illinois University Edwardsville, or visit the conference website listed below: Conference: ACM-SIGMIS Computer Personnel Research 2005 (CPR2005) Conference Theme: "Beyond the Bust: Preparing for the Boom?" Dates: April 14-16, 2005 Location: Atlanta, Georgia USA Website: http://www.acm.org/sigmis/CFP2005.html

Radiation doses to local populations near nuclear weapons test sites worldwide.

Nuclear weapons testing was conducted in the atmosphere at numerous sites worldwide between 1946 and 1980, which resulted in exposures to local populations as a consequence of fallout of radioactive debris. The nuclear tests were conducted by five nations (United States, Soviet Union, United Kingdom, France, and China) primarily at 16 sites. The 16 testing sites, located in nine different countries on five continents (plus Oceania) contributed nearly all of the radioactive materials released to the environment by atmospheric testing; only small amounts were released at a fewother minor testing sites. The 16 sites discussed here are Nevada Test Site, USA (North American continent), Bikini and Enewetak, Marshall Islands (Oceania); Johnston Island, USA (Oceania), Christmas and Malden Island, Kiribati (Oceania); Emu Field, Maralinga, and Monte Bello Islands, Australia (Australian continent); Mururoa and Fangataufa, French Polynesia (Oceania), Reggane, Algeria (Africa), Novaya Zemlya and Kapustin Yar, Russia (Europe), Semipalatinsk, Kazakhstan (Asia), and Lop Nor, China (Asia). There were large differences in the numbers of tests conducted at each location and in the total explosive yields. Those factors, as well as differences in population density, lifestyle, environment, and climate at each site, led to large differences in the doses received by local populations. In general, the tests conducted earliest led to the highest individual and population exposures, although the amount of information available for a few of these sites is insufficient to provide any detailed evaluation of radiation exposures. The most comprehensive information for any site is for the Nevada Test Site. The disparities in available information add difficulty to determining the radiation exposures of local populations at each site. It is the goal of this paper to summarize the available information on external and internal doses received by the public living in the regions near each of the mentioned nuclear test sites as a consequence of local fallout deposition.

Detour through Casino - Comdex Fall '94, November 14-18, Las Vegas, Nevada USA

Detour through Casino - Comdex Fall '94, November 14-18, Las Vegas, Nevada USA