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Concentrating solar power (CSP) plants convert solar energy to electricity and can be deployed with a thermal storage capability to shift electricity generation from time periods with available solar resource to those with high electricity demand or electricity price. Rigorous optimization of plant design and operational strategies can improve the market-competitiveness and commercial viability; however, such optimization may require hundreds of annual performance simulations, each of which can be computationally expensive when including considerations such as optimization of dispatch scheduling, sub-hourly time resolution, and stochastic effects due to uncertain weather or electricity price forecasts. This paper proposes a methodology to reduce the computational burden associated with simulation of electricity yield and revenue for CSP plants over a single- or multi-year period. Data-clustering techniques are employed to select a small number of limited-duration time blocks for simulation that, when appropriately weighted, can reproduce generation and revenue over a single year or within each year of a multi-year period. After selection of appropriate data features and weighting factors defining similarity between time-series profiles, the methodology captured annual revenue within 2.3%, 1.7%, or 1.2% using simulation of 10, 30, or 50 three-day exemplar time blocks, respectively, for each of three single-year location/weather/market scenarios and five plant configurations ranging from low to high solar multiple and storage capacity. When applied to multi-year datasets, the proposed methodology can capture inter-year variability that is unavailable from typical meteorological year (TMY) datasets while simultaneously requiring simulation of less than a single year of data.

Hypothesis Most functional inkjet inks are sterically stabilized nanoparticle dispersions that require a post-printing-process to remove stabilizing materials and gain functionality. This post-process limits material selection and increases fabrication time and complexity for printed devices. By optimizing the electrostatic stability of a carbon nanomaterial dispersed in water or ethylene glycol via pH adjustment, a stable and printable ink should be attainable without a steric stabilizing material and hence the post-process may be avoided. Experiments The electrostatic stability of multilayer graphene nanoshells (MGNS)—an inexpensive and net carbon-negative nanomaterial—dispersed in water and ethylene glycol was studied by measuring zeta potential as a function of pH and modeling energetic potentials between particles. Requirements for electrical percolation of printed MGNS were analyzed and corroborated with electrical measurements. Findings Electrostatic stability improved with increased zeta potential caused by an increased pH. Ionic strength also increased with pH, causing strong destabilization. By increasing zeta potential while minimizing ionic strength, the maximum solid-loading of MGNS in DI water and ethylene glycol was increased up to 20%. For the MGNS solid-loading achieved here, electrical percolation occurs with 20–30 consecutively printed layers producing a resistivity of 30 Ω-cm. The inexpensive, environmentally-friendly MGNS are a promising material for printed, flexible electronics.

When the COVID-19 pandemic began, formal frameworks to collect data about affected patients were lacking. The COVID-19 and Cancer Consortium (CCC19) was formed to collect granular data on patients with cancer and COVID-19 at scale and as rapidly as possible. CCC19 has grown from five initial institutions to 125 institutions with >400 collaborators. More than 5,000 cases with complete baseline data have been accrued. Future directions include increased electronic health record integration for direct data ingestion, expansion to additional domestic and international sites, more intentional patient involvement, and granular analyses of still-unanswered questions related to cancer subtypes and treatments.

The optical performance of a concentrating solar power (CSP) collector is critical to the overall efficiency of the system. This study presents a detailed optical comparison between three representative CSP collector designs including linear Fresnel, parabolic trough, and central-receiver technologies. Optical models are implemented in SolTrace, which is ray-tracing software developed at the National Renewable Energy Laboratory. The ray-tracing algorithm is used to calculate a collector’s design-point performance as well as its incidence-angle modifiers to evaluate the collector performance at any sun position during a typical meteorological year. The efficiency over a one-year period is then analyzed based on ray-tracing results. Using China Lake (California) as an example, the annual optical efficiency is 60% for the selected parabolic trough collector, 52% for the selected central-receiver technology, and 40% for the selected linear Fresnel collector. The parabolic trough has the highest optical performance among all. The selected central-receiver technology provides the most consistent seasonal production profile over the course of the year due to its two-axis-tracking ability but would suffer most from the increasing solar collector optical error. It is also shown that a dramatic cost reduction is required for the selected linear Fresnel technology to be competitive in the future energy market. Sensitivity of three CSP technologies to the deployment locations and the overall optical-error magnitude is also examined through annual performance analysis. The results will provide insights into a better understanding on inherent technical aspects of different CSP technologies.

Concentrating solar power (CSP) systems employ a sophisticated thermal receiver, power cycle, and a heliostat field, comprised of thousands of mirrors spread over hundreds of acres of land, and are most cost-effective with relatively large quantities of energy storage which can be scheduled for dispatch. We exercise an existing optimization model that maximizes revenue over a year-long time horizon, solved using a standard 48-h look-ahead policy at hourly fidelity on a CSP system under development in California. The system employs molten salt power tower technology with a 150 MW e (net) turbine, eight hours of thermal storage at full load, and a solar field that provides 1.75 times the rated turbine thermal power. The model considers system configuration and interoperability aspects, such as storage tank size, production capacities, and ramp rates, and determines decisions that expedite financing, permitting, and plant design. Relative to results achieved via industry practice, the existing optimization model reduces the number of power cycle (i.e., turbine) start-up events by 86.4%, thereby improving net revenue by more than 8.5% annually; this corresponds to an approximately $140 M increase in net revenue over the lifetime of the plant, taking a step towards advancing the long-term economic viability of large-scale renewable energy systems. Sensitivity analysis on uncertain parameter values provides insight regarding those values that influence profit most significantly.

Gold-coated gadolinium nanocrystals have been synthesized and their relaxivities, R1 and R2, found to be 19.7 and 21.7 s−1 mM−1 respectively at a 9.4 T applied field. R1 is more than 3 times higher than commercial Gd3+ chelate contrast agents on a per Gd atom basis and over 3000 times higher on a per nanocrystal (molecule) basis. Furthermore, the R2/R1 ratio, 1.1, is near ideal for a T1 contrast agent. Colloids of the PVP coated Gd@Au nanocrystals are stable in solution at physiological pH for more than a week. The Au shell protects the Gd from reaction over even in low pH solution. These results indicate that Gd@Au is an exceptionally promising candidate for development as an MRI T1 contrast agent for molecular imaging.

Concentrating solar power towers, which include a steam-Rankine cycle with molten salt thermal energy storage, is an emerging technology whose maximum effectiveness relies on an optimal operational and dispatch policy. Given parameters such as start-up and shut-down penalties, expected electricity price profiles, solar availability, and system interoperability requirements, this paper seeks a profit-maximizing solution that determines start-up and shut-down times for the power cycle and solar receiver, and the times at which to dispatch stored and instantaneous quantities of energy over a 48-h horizon at hourly fidelity. The mixed-integer linear program (MIP) is subject to constraints including: (i) minimum and maximum rates of start-up and shut-down, (ii) energy balance, including energetic state of the system as a whole and its components, (iii) logical rules governing the operational modes of the power cycle and solar receiver, and (iv) operational consistency between time periods. The novelty in this work lies in the successful integration of a dispatch optimization model into a detailed techno-economic analysis tool, specifically, the National Renewable Energy Laboratory’s System Advisor Model (SAM). The MIP produces an optimized operating strategy, historically determined via a heuristic. Using several market electricity pricing profiles, we present comparative results for a system with and without dispatch optimization, indicating that dispatch optimization can improve plant profitability by 5–20% and thereby alter the economics of concentrating solar power technology. While we examine a molten salt power tower system, this analysis is equally applicable to the more mature concentrating solar parabolic trough system with thermal energy storage.

The magnetic properties of little examined CuCl 2 ·2D 2 O are studied and compared with those of CuCl 2 ·2H 2 O. New CuBr 2 ·6H 2 O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ M = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr 2 . A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr 2 , but with almost twice the magnitude. Powder X-ray diffraction data for CuBr 2 ·6H 2 O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

Magnetic measurements on variously hydrated nickel chlorides and bromides, including deuterated forms, are reported. Results include locations and sizes of susceptibility maxima, T max and χ max , ordering temperatures T c , Curie constants and Weiss theta in the paramagnetic regime, and primary and secondary exchange interactions from analysis of low temperature data. For the latter a 2D Heisenberg model augmented by interlayer exchange in a mean-field approximation is applied. Magnetization data to 16 kG as a function of temperature show curvature and hysteresis characteristics quite system dependent. For four materials high field magnetization data to 70 kG at 2.00 K are also obtained. Comparison is made with theoretical relations for spin-1 models. Trends are apparent, primarily that T max of each bromide hydrate is less than for the corresponding chloride, and that for a given halide n D 2 O ( n =1 or 2) deuterates exhibit lesser T max than do nH 2 O hydrates. A monoclinic unit cell determined from powder X-ray diffraction data on NiBr 2 ·2D 2 O is different from and slightly larger than that of NiBr 2 ·2H 2 O. This provides some rationale for the difference in magnetic properties between these.

The magnetic properties of previously unexamined MnBr 2 ·2H 2 O, MnBr 2 ·H 2 O, MnBr 2 ·2D 2 O and MnBr 2 ·D 2 O are studied. Curie–Weiss fits to high temperature data yield θ of −13.1, −3.9, −8.2 and −5.0 K, respectively, in χ M = C /( T − θ ). The net antiferromagnetic exchange yields susceptibility maxima at 6.34, 3.20, 2.10, and 3.40 K, with χ max of 0.197, 0.357, 0.465 and 0.348 emu/mol, respectively. Noteworthy is the contrast between dideuterate and dihydrate, the largest deuteration effect observed for hydrated transition metal halides. Antiferromagnetic ordering is estimated to occur at 5.91, 2.65, 2.00 and 2.50 K, respectively. The ratio T c / T max is 0.93, 0.83, 0.95 and 0.74 in the same order, implying low dimensional magnetism for monohydrate and monodeuterate. Heisenberg model fits to susceptibilities yield primary and secondary exchange interactions. Magnetization data at moderate fields and different temperatures are presented for each substance, and high field data to 70 kG at 2.00 K. Spin-flop transitions are estimated to occur at 45, 33 and 30 kG, respectively, for dihydrate, monohydrate and monodeuterate, but are not observable for MnBr 2 ·2D 2 O. The results are analyzed from various perspectives. A different monoclinic unit cell is determined for MnBr 2 ·2D 2 O than for MnBr 2 ·2H 2 O, with 1.3% larger volume, providing some rationale for the difference in magnetic properties.

This paper presents a model for improving off-design performance predictions for molten salt-driven Rankine power cycles, such as in concentrating solar power tower applications. The model predicts cycle off-design performance under various boundary conditions, including molten salt inlet temperature, mass flow rate, and ambient temperature. The model is validated using industry performance data and benchmarked with results from the literature. A complete concentrating solar power plant, inclusive of solar heliostat field and receiver, is then considered, by implementing the Rankine cycle off-design performance results into the National Renewable Energy Laboratory’s System Advisor Model software, which includes a tool that determines optimal power production schedules. The work improves upon the current System Advisor Model by updating off-design performance characteristics. A case study demonstrates the impact of cycle off-design behavior on annual performance for a stand-alone concentrating solar power system and a concentrating solar power-photovoltaic hybrid system. In addition, we demonstrate how cycle off-design performance influences optimal operator dispatch decisions and, thereby, overall system design and economics. We conclude that off-design cycle performance impacts “optimal” sub-system sizing, especially for a concentrating solar power-photovoltaic hybrid configuration in which concentrating solar power must dispatch in conjunction with photovoltaic generation.

Linear Fresnel collectors are a type of concentrating solar power technology. In this paper, the technology’s technical features and aspects are first described via illustrations of various design concepts; then, the past low- and intermediate-temperature applications of linear Fresnel collectors are reviewed and their state-of-the-art applications in utility-scale electricity generation are presented; finally, the performance, technical challenges, and future outlook of linear Fresnel technology in the context of utility-scale power plants are summarized.

The System Advisor Model (SAM) is modeling software for renewable energy systems developed by the National Renewable Energy Laboratory (NREL).SAM combines annual time series power production models with financial models to estimate the levelized cost of energy (LCOE) and other metrics for renewable energy projects. To date, SAM has utilized the general purpose commercial TRNSYS transient systems modeling software package for CSP simulations and originally PV and wind. To achieve: (1) significantly faster model performance, (2) easy parallelization of concurrent simulations to take advantage of modern multi-core processor desktop computers, (3) to allow straightforward modification of CSP component models in the SAM environment, and (4) ability to include CSP technologies in the SAM Software Development Kit (SDK), NREL has undertaken to reformulate the CSP models into a new transient simulation framework written in C++, by NREL. This framework is tailored specifically for use in SAM and not for general purpose modeling like TRNSYS. Preliminary results show excellent matching with the accepted TRNSYS-based models, as well as an order of magnitude reduction in simulation time for certain models. These runtime reductions enable larger scale plant configuration analysis, as well as grid-integration studies that require many thousands of simulations.

Yield analysis is a crucial task during project deployment of solar thermal power plants. Currently, many different modeling approaches and computer tools for yield analysis are used. Within the SolarPACES project guiSmo, aiming at the development of guidelines for the annual yield prediction of solar thermal power plants, relevant effects for the steady-state modeling of plant sub-systems have been identified [1] . The target of the ongoing project phase is the development of general definitions for all relevant effects. Furthermore, suitable modeling approaches have to be identified and described unambiguously. For every effect, the impact on the predicted electricity yield is estimated in order to assess the significance of the considered effect. Since the most significant effects have to be considered in a subsequent uncertainty analysis, reasonable model and parameter uncertainties have to be defined, too. Finally, default model parameter for state-of-the-art components or subsystems will be edited. Beside the present status of the project, this paper presents investigations on the effects of the optical losses of the sub-system collector field on the annual yield. These effects are namely the peak optical efficiency, incidence angle modifier (IAM), shading and end losses. For each effect, a precise definition is presented and relevant modeling approaches are identified and their pros and cons are discussed. To investigate the influence of these effects, a reference solar thermal power plant with parabolic troughs is defined. The annual yield is simulated for this reference system investigating the identified modeling approaches and assessing their significance.

A novel Li/H2O primary battery is reported. The battery consists of a thin film lithium metal anode evaporated on hybrid inorganic/organic lithium ion conductive solid electrolyte, H2O as the electroactive cathode material, and a Pt mesh current collector. The hybrid electrolyte consists of a two-phase ceramic, lithium aluminum titanium phosphate/aluminum phosphate (LATP/AlPO4), sealed with polyvinylidene fluoride. These cells display an open cell potential of 0.90 V, a current output range between 0.78 and 0.50 μA under constant 1 MΩ load discharge, and specific energy of 2660 Wh/kg. Battery life is shown to be proportional to the mass of the Li metal anode employed and has been demonstrated for up to 37.5 h.

The Great Lakes Fishery Commission (GLFC) considers the application of sea lamprey pheromones a promising alternative-control method for its sea lamprey management program. Several components of two pheromones that regulate migration and reproduction, respectively, have been identified and synthesized. Potential utility of these pheromone compounds in lamprey management have been demonstrated in a series of field experiments. These discoveries have laid a solid foundation for development of pheromone-based management. In order to identify potential strategies that will be practical, effective, and economical, we propose a hypothesis driven approach that integrates concepts and experimental methods from several disciplines of biological science, such as neurobiology, biochemistry, and behavioral ecology to illustrate the exact function of identified compounds. In the interim, we identify the necessary steps, or issues critical to eventual implementation, to charter a pathway that leads from laboratory research to effective deployment of pheromones. Finally, we highlight a strategy that fosters collaboration among scientists across disciplines, as well as among research institutes and lamprey control agencies, to accomplish this research agenda.

Recent advances in technologies for high-throughout single-nucleotide polymorphism (SNP)–based genotyping have improved efficiency and cost so that it is now becoming reasonable to consider the use of SNPs for genomewide linkage analysis. However, a suitable screening set of SNPs and a corresponding linkage map have yet to be described. The SNP maps described here fill this void and provide a resource for fast genome scanning for disease genes. We have evaluated 6,297 SNPs in a diversity panel composed of European Americans, African Americans, and Asians. The markers were assessed for assay robustness, suitable allele frequencies, and informativeness of multi-SNP clusters. Individuals from 56 Centre d'Etude du Polymorphisme Humain pedigrees, with >770 potentially informative meioses altogether, were genotyped with a subset of 2,988 SNPs, for map construction. Extensive genotyping-error analysis was performed, and the resulting SNP linkage map has an average map resolution of 3.9 cM, with map positions containing either a single SNP or several tightly linked SNPs. The order of markers on this map compares favorably with several other linkage and physical maps. We compared map distances between the SNP linkage map and the interpolated SNP linkage map constructed by the deCode Genetics group. We also evaluated cM/Mb distance ratios in females and males, along each chromosome, showing broadly defined regions of increased and decreased rates of recombination. Evaluations indicate that this SNP screening set is more informative than the Marshfield Clinic’s commonly used microsatellite-based screening set.

The genotyping of closely spaced single-nucleotide polymorphism (SNP) markers frequently yields highly correlated data, owing to extensive linkage disequilibrium (LD) between markers. The extent of LD varies widely across the genome and drives the number of frequent haplotypes observed in small regions. Several studies have illustrated the possibility that LD or haplotype data could be used to select a subset of SNPs that optimize the information retained in a genomic region while reducing the genotyping effort and simplifying the analysis. We propose a method based on the spectral decomposition of the matrices of pairwise LD between markers, and we select markers on the basis of their contributions to the total genetic variation. We also modify Clayton’s “haplotype tagging SNP” selection method, which utilizes haplotype information. For both methods, we propose sliding window–based algorithms that allow the methods to be applied to large chromosomal regions. Our procedures require genotype information about a small number of individuals for an initial set of SNPs and selection of an optimum subset of SNPs that could be efficiently genotyped on larger numbers of samples while retaining most of the genetic variation in samples. We identify suitable parameter combinations for the procedures, and we show that a sample size of 50–100 individuals achieves consistent results in studies of simulated data sets in linkage equilibrium and LD. When applied to experimental data sets, both procedures were similarly effective at reducing the genotyping requirement while maintaining the genetic information content throughout the regions. We also show that haplotype-association results that Hosking et al. obtained near CYP2D6 were almost identical before and after marker selection.

We have constructed a physical map covering over 4 Mb of human chromosome 8q24.1 and used this map to refine the locations of the genes responsible for Langer-Giedion syndrome. The map is composed of overlapping YAC clones that were identified and ordered in relation to sequence tagged sites mapped to the Langer-Giedion chromosomal region on somatic cell hybrids. The minimal region of overlap of Langer-Giedion syndrome deletions, previously identified by analysis of 15 patients, was placed on the map by analysis of 2 patients whose deletions define the endpoints. The chromosome 8 breakpoint of a balanced t(8;9)(q24.11;q33.3) translocation from a patient with trichorhinophalangeal syndrome (TRPS I) was found to be located just within the proximal end of the minimal deletion region. A deletion of 8q24.11-q24.3 in a patient with multiple exostoses was found to overlap the distal end of the LGS deletion region, indicating that the EXT1 gene is distal to the TRPS1 gene and supporting the hypothesis that Langer-Giedion syndrome is due to loss of functional copies of both the TRPS1 and the EXT1 genes.

Microcell hybrids containing various regions of human chromosome 8 were formed by microcell-mediated transfer of neo-tagged chromosome 8 into the cells derived from severe combined immunodeficiency (SCID) mouse. Thus, 110 cosmid markers were isolated from SV40-transformed SCID fibroblast cell line (SCVA) containing a p12-q11.1 region of human chromosome 8 and were assigned to eight regions in 8p12-q11.1, using a microcell-hybrid panel. For positional cloning of a human gene that restores the DNA-repair defect in a mouse with SCID on 8p11.1-q11.1 (SCID region), we constructed a yeast artificial chromosome (YAC) contig of about 4.5 Mb. Overlapping YACs were further aligned by restriction mapping, using rare-cutting restriction endonucleases. The cosmids and YAC contig should facilitate isolation of the SCID gene and other genes, such as the Werner syndrome-responsible gene in or near this region.

The sizes and structures of cavities and channels in the first crystalline mixed crown electride, [Cs{sup +}(18-crown-6)(15-crown-5)e{sup {minus}}]{sub 6}{center_dot}(18C6), are reported and related to its properties. The structure consists of cesium cations complexed by one each of the 18-crown-6 and 15-crown-5 complexants, which pack to leave a remarkable ring of six cavities that are presumed to be the trapping sites of the excess electrons. The sizes and shapes of the cavities and connecting channels are described in detail with the aid of a newly developed computer program. The magnetic susceptibility (corrected for the low-temperature {open_quotes}tail{close_quotes} due to defect electrons) is shown to be consistent with that expected for an antiferromagnetically coupled 6-electron ring and yields an estimate of the coupling strength, J/k, of {approximately}-410K. {sup 133}CsMAS NMR and the temperature dependence of the magnetic susceptibility show that the electron density at the cation nucleus is an order of magnitude smaller than that of either Cs{sup +}(18-crown-6){sub 2}e{sup {minus}} or Cs{sup +}(15-crown-5){sub 2}e{sup {minus}}. The compound is moderately conductive with a lower limit of conductivity at 213 K estimated to be 2 x 10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1}. The dominant conduction mechanism is probably variable range hopping of defect electrons.

We have developed a panel of radiation hybrids containing fragments of chromosome 8 as the only human material. The human chromosome content of each cell line was determined relative to an ordered map of sequence tagged sites (STSs) specific to chromosome 8. Between one and four fragments of chromosome 8 were identified in each cell line, with an average of 25% of the STSs retained in each line. Subclones of one radiation hybrid were examined to determine whether all cells within a line are homogeneous with respect to chromosome 8 sequence content. There was considerable variability between subclones, with retention rates for individual STSs ranging from 5 to 100% in different clones. Furthermore, a gradient of retention of sequences along the length of one large chromosome fragment was found, suggesting that sequence loss involved deletions from one end of the fragment at early stages in the establishment of the cell line. We have also made use of the radiation hybrids to develop novel sequence tagged sites for the pericentromeric region of chromosome 8.

We have characterized alphoid repeat clones derived from a chromosome 8 library. These clones are specific for human chromosome 8, as demonstrated by use of a somatic cell hybrid mapping panel and by in situ hybridization. Hybridization of the clones to Hin dIII digests of human genomic DNA reveals a complex pattern of fragments ranging in size from 1.3 to >20 kb. One clone, which corresponds in size to the most prevalent genomic Hin dIII fragment, appears to represent a major higher order repeat in the chromosome 8 centromere. The DNA sequence of this clone reveals a dimeric organization of alphoid monomers. Restriction analysis of two other clones indicates that they are derivatives of this same repeat unit. The chromosome 8 alphoid clones hybridize to Eco RI fragments of genomic DNA ranging up to 1000 kb in length and reveal a high degree of polymorphism between chromosomes. Distribution of higher order repeat units across the centromere was examined by two-dimensional gel electrophoresis. Repeat units of the same size class tended to cluster together in restricted regions of centromeric DNA.

Rationale The prevalence of asthma and other allergic diseases has risen to above 10% over the past 2 decades. Genome wide screens for asthma phenotypes have been completed in several populations. Overall results from these genome scans differ significantly, which could mainly be attributed to the sample size, and the choice of phenotypes/populations. We conducted a genome scan using a large population to identify asthma susceptibility genes. Methods An asthma Genetics program was initiated at GSK in 1998 which includes the Genetics of Asthma International network (GAIN) and two independent collections from Denmark and Minnesota. We collected ∼1500 families from 13 collection centers in Europe Australia and US. A genome scan using 735 families was performed with 390 markers representing an approximate 7-cM genome scan set (752 affected sib pairs for Physician's Diagnosis of Asthma, PDA). Multi-point linkage analysis was performed with Genehunter using four phenotypes; PDA, atopic asthma, BHR (bronchial hyper-responsiveness) and strict asthma (2 of 3 symptoms + BHR). Results Preliminary results showed the following 5 chromosomal regions with a LOD greater than 2.0, Chromosome 1, LOD score 2.014 for atopic asthma; Chromosome 2, LOD score 2.23 for strict asthma and/ BHR; chromosome 4, LOD score 2.43 for BHR; chromosome 6, LOD score 2.06 for strict asthma; and chromosome 12, LOD score 2.03 for physician's diagnosis of asthma. Conclusions The improved power associated with the better sample size has led to the identification of several genomic regions linked to asthma, including a potentially novel locus on chromosome 4.