Showing papers by "Ohio State University published in 2005"
TL;DR: Nanotechnology is a multidisciplinary field, which covers a vast and diverse array of devices derived from engineering, biology, physics and chemistry that can provide essential breakthroughs in the fight against cancer.
Abstract: Nanotechnology is a multidisciplinary field, which covers a vast and diverse array of devices derived from engineering, biology, physics and chemistry. These devices include nanovectors for the targeted delivery of anticancer drugs and imaging contrast agents. Nanowires and nanocantilever arrays are among the leading approaches under development for the early detection of precancerous and malignant lesions from biological fluids. These and other nanodevices can provide essential breakthroughs in the fight against cancer.
4,241 citations
TL;DR: It is shown that, compared with normal breast tissue, miRNAs are also aberrantly expressed in human breast cancer, and the overall miRNA expression could clearly separate normal versus cancer tissues, with the most significantly deregulated mi RNAs being mir-125b, mir-145, mir -21, and mir-155.
Abstract: MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting mRNAs and triggering either translation repression or RNA degradation Their aberrant expression may be involved in human diseases, including cancer Indeed, miRNA aberrant expression has been previously found in human chronic lymphocytic leukemias, where miRNA signatures were associated with specific clinicobiological features Here, we show that, compared with normal breast tissue, miRNAs are also aberrantly expressed in human breast cancer The overall miRNA expression could clearly separate normal versus cancer tissues, with the most significantly deregulated miRNAs being mir-125b, mir-145, mir-21, and mir-155 Results were confirmed by microarray and Northern blot analyses We could identify miRNAs whose expression was correlated with specific breast cancer biopathologic features, such as estrogen and progesterone receptor expression, tumor stage, vascular invasion, or proliferation index
4,076 citations
TL;DR: It is demonstrated thatmiR-15a and miR-16-1 expression is inversely correlated to Bcl2 expression in CLL and that both microRNAs negatively regulate BCL2 at a posttranscriptional level and are natural antisense B cl2 interactors that could be used for therapy of Bcl1-overexpressing tumors.
Abstract: Chronic lymphocytic leukemia (CLL) is the most common human leukemia and is characterized by predominantly nondividing malignant B cells overexpressing the antiapoptotic B cell lymphoma 2 (Bcl2) protein miR-15a and miR-16-1 are deleted or down-regulated in the majority of CLLs Here, we demonstrate that miR-15a and miR-16-1 expression is inversely correlated to Bcl2 expression in CLL and that both microRNAs negatively regulate Bcl2 at a posttranscriptional level BCL2 repression by these microRNAs induces apoptopsis in a leukemic cell line model Therefore, miR-15 and miR-16 are natural antisense Bcl2 interactors that could be used for therapy of Bcl2-overexpressing tumors
3,567 citations
TL;DR: Older monozygous twins exhibited remarkable differences in their overall content and genomic distribution of 5-methylcytosine DNA and histone acetylation, affecting their gene-expression portrait, indicating how an appreciation of epigenetics is missing from the understanding of how different phenotypes can be originated from the same genotype.
Abstract: Monozygous twins share a common genotype. However, most monozygotic twin pairs are not identical; several types of phenotypic discordance may be observed, such as differences in susceptibilities to disease and a wide range of anthropomorphic features. There are several possible explanations for these observations, but one is the existence of epigenetic differences. To address this issue, we examined the global and locus-specific differences in DNA methylation and histone acetylation of a large cohort of monozygotic twins. We found that, although twins are epigenetically indistinguishable during the early years of life, older monozygous twins exhibited remarkable differences in their overall content and genomic distribution of 5-methylcytosine DNA and histone acetylation, affecting their gene-expression portrait. These findings indicate how an appreciation of epigenetics is missing from our understanding of how different phenotypes can be originated from the same genotype.
3,330 citations
TL;DR: In this paper, soil organic carbon (SOC), biota, ionic bridging, clay and carbonates are associated with aggregation by rearrangement, flocculation and cementation.
3,241 citations
TL;DR: Using the models, the authors have shown the calculation of a Cramer-Rao bound (CRB) on the location estimation precision possible for a given set of measurements in wireless sensor networks.
Abstract: Accurate and low-cost sensor localization is a critical requirement for the deployment of wireless sensor networks in a wide variety of applications. In cooperative localization, sensors work together in a peer-to-peer manner to make measurements and then forms a map of the network. Various application requirements influence the design of sensor localization systems. In this article, the authors describe the measurement-based statistical models useful to describe time-of-arrival (TOA), angle-of-arrival (AOA), and received-signal-strength (RSS) measurements in wireless sensor networks. Wideband and ultra-wideband (UWB) measurements, and RF and acoustic media are also discussed. Using the models, the authors have shown the calculation of a Cramer-Rao bound (CRB) on the location estimation precision possible for a given set of measurements. The article briefly surveys a large and growing body of sensor localization algorithms. This article is intended to emphasize the basic statistical signal processing background necessary to understand the state-of-the-art and to make progress in the new and largely open areas of sensor network localization research.
3,080 citations
TL;DR: In this paper, the most important experimental results from the first three years of nucleus-nucleus collision studies at RHIC were reviewed, with emphasis on results of the STAR experiment.
2,750 citations
TL;DR: A unique microRNA signature is associated with prognostic factors and disease progression in CLL, and a germ-line mutation in the miR-16-1-miR-15a primary precursor caused low levels of microRNA expression in vitro and in vivo and was associated with deletion of the normal allele.
Abstract: Background MicroRNA expression profiles can be used to distinguish normal B cells from malignant B cells in patients with chronic lymphocytic leukemia (CLL). We investigated whether microRNA profiles are associated with known prognostic factors in CLL. Methods We evaluated the microRNA expression profiles of 94 samples of CLL cells for which the level of expression of 70-kD zeta-associated protein (ZAP-70), the mutational status of the rearranged immunoglobulin heavy-chain variable-region (IgVH ) gene, and the time from diagnosis to initial treatment were known. We also investigated the genomic sequence of 42 microRNA genes to identify abnormalities. Results A unique microRNA expression signature composed of 13 genes (of 190 analyzed) differentiated cases of CLL with low levels of ZAP-70 expression from those with high levels and cases with unmutated IgVH from those with mutated IgVH . The same microRNA signature was also associated with the presence or absence of disease progression. We also identified a...
2,554 citations
TL;DR: In this article, the authors show that at low z < 1, the cosmic star formation rate degrades due to geometry, as the typical cross section of filaments begins to exceed that of the galaxies at their intersections.
Abstract: Not the way one might have thought. In hydrodynamic simulations of galaxy formation, some gas follows the traditionally envisioned route, shock heating to the halo virial temperature before cooling to the much lower temperature of the neutral ISM. But most gas enters galaxies without ever heating close to the virial temperature, gaining thermal energy from weak shocks and adiabatic compression, and radiating it just as quickly. This “cold mode” accretion is channeled along filaments, while the conventional, “hot mode” accretion is quasi-spherical. Cold mode accretion dominates high redshift growth by a substantial factor, while at z < 1 the overall accretion rate declines and hot mode accretion has greater relative importance. The decline of the cosmic star formation rate at low z is driven largely by geometry, as the typical cross section of filaments begins to exceed that of the galaxies at their intersections.
2,155 citations
TL;DR: The ADHERE registry as mentioned in this paper is designed to study characteristics, management, and outcomes in a broad sample of patients hospitalized with acute decompensated heart failure, which is a leading cause of hospitalization for adults older than 65 years in the United States.
1,913 citations
TL;DR: PNI researchers have used animal and human models to learn how the immune system communicates bidirectionally with the central nervous and endocrine systems and how these interactions impact on health.
Abstract: Folk wisdom has long suggested that stressful events take a toll on health. The field of psychoneuroimmunology (PNI) is now providing key mechanistic evidence about the ways in which stressors--and the negative emotions that they generate--can be translated into physiological changes. PNI researchers have used animal and human models to learn how the immune system communicates bidirectionally with the central nervous and endocrine systems and how these interactions impact on health.
TL;DR: In this paper, the authors report changes in teacher efficacy from entry into a teacher preparation program through the induction year and found significant increases in efficacy during student teaching, but significant declines during the first year of teaching.
TL;DR: Several compounds from tropical rainforest plant species with potential anticancer activity have been identified and several compounds, mainly from edible plant species or plants used as dietary supplements, that may act as chemopreventive agents are isolated.
TL;DR: A review and introduction to the Special Issue on Strategy Research in Emerging Economies as mentioned in this paper considers the nature of theoretical contributions thus far on strategy in emerging economies and classify the research through four strategic options: (1) firms from developed economies entering emerging economies; (2) domestic firms competing within emerging economies, (3), firms from emerging economies entering other emerging economies.
Abstract: This review and introduction to the Special Issue on ‘Strategy Research in Emerging Economies’ considers the nature of theoretical contributions thus far on strategy in emerging economies. We classify the research through four strategic options: (1) firms from developed economies entering emerging economies; (2) domestic firms competing within emerging economies; (3) firms from emerging economies entering other emerging economies; and (4) firms from emerging economies entering developed economies. Among the four perspectives examined (institutional theory, transaction cost theory, resource-based theory, and agency theory), the most dominant seems to be institutional theory. Most existing studies that make a contribution blend institutional theory with one of the other three perspectives, including seven out of the eight papers included in this Special Issue. We suggest a future research agenda based around the four strategies and four theoretical perspectives. Given the relative emphasis of research so far on the first and second strategic options, we believe that there is growing scope for research that addresses the third and fourth.
TL;DR: The results suggest that ADHF patients at low, intermediate, and high risk for in-hospital mortality can be easily identified using vital sign and laboratory data obtained on hospital admission and provides clinicians with a validated, practical bedside tool for mortality risk stratification.
Abstract: ContextEstimation of mortality risk in patients hospitalized with acute decompensated
heart failure (ADHF) may help clinicians guide care.ObjectiveTo develop a practical user-friendly bedside tool for risk stratification
for patients hospitalized with ADHF.Design, Setting, and PatientsThe Acute Decompensated Heart Failure National Registry (ADHERE) of
patients hospitalized with a primary diagnosis of ADHF in 263 hospitals in
the United States was queried with analysis of patient data to develop a risk
stratification model. The first 33 046 hospitalizations (derivation cohort;
October 2001-February 2003) were analyzed to develop the model and then the
validity of the model was prospectively tested using data from 32 229 subsequent
hospitalizations (validation cohort; March-July 2003). Patients had a mean
age of 72.5 years and 52% were female.Main Outcome MeasureVariables predicting mortality in ADHF.ResultsWhen the derivation and validation cohorts are combined, 37 772 (58%)
of 65 275 patient-records had coronary artery disease. Of a combined cohort
consisting of 52 164 patient-records, 23 910 (46%) had preserved left ventricular
systolic function. In-hospital mortality was similar in the derivation (4.2%)
and validation (4.0%) cohorts. Recursive partitioning of the derivation cohort
for 39 variables indicated that the best single predictor for mortality was
high admission levels of blood urea nitrogen (≥43 mg/dL [15.35 mmol/L])
followed by low admission systolic blood pressure (<115 mm Hg) and then
by high levels of serum creatinine (≥2.75 mg/dL [243.1 μmol/L]). A simple
risk tree identified patient groups with mortality ranging from 2.1% to 21.9%.
The odds ratio for mortality between patients identified as high and low risk
was 12.9 (95% confidence interval, 10.4-15.9) and similar results were seen
when this risk stratification was applied prospectively to the validation
cohort.ConclusionsThese results suggest that ADHF patients at low, intermediate, and high
risk for in-hospital mortality can be easily identified using vital sign and
laboratory data obtained on hospital admission. The ADHERE risk tree provides
clinicians with a validated, practical bedside tool for mortality risk stratification.
TL;DR: As a cluster of recent Nature papers now show, altered expression of specific miRNA genes contributes to the initiation and progression of cancer.
Broad Institute1, J. Craig Venter Institute2, Stanford University3, Oregon Health & Science University4, University of Glasgow5, Genetic Information Research Institute6, Institut Universitaire de France7, University of Kentucky8, University of Nebraska–Lincoln9, University of Göttingen10, Pasteur Institute11, University of São Paulo12, Texas A&M University13, Wellcome Trust Sanger Institute14, John Innes Centre15, University of Wisconsin-Madison16, Max Planck Society17, University of Oregon18, University of Nottingham19, Spanish National Research Council20, Ohio State University21, University of Georgia22, Tokyo Institute of Technology23, National Institute of Advanced Industrial Science and Technology24, George Washington University25, University of Manchester26, University of Liverpool27, University of Melbourne28, Karlsruhe Institute of Technology29, University of Idaho30
TL;DR: The aspergilli comprise a diverse group of filamentous fungi spanning over 200 million years of evolution, and a comparative study with Aspergillus fumigatus and As pergillus oryzae, used in the production of sake, miso and soy sauce, provides new insight into eukaryotic genome evolution and gene regulation.
Abstract: The aspergilli comprise a diverse group of filamentous fungi spanning over 200 million years of evolution. Here we report the genome sequence of the model organism Aspergillus nidulans, and a comparative study with Aspergillus fumigatus, a serious human pathogen, and Aspergillus oryzae, used in the production of sake, miso and soy sauce. Our analysis of genome structure provided a quantitative evaluation of forces driving long-term eukaryotic genome evolution. It also led to an experimentally validated model of mating-type locus evolution, suggesting the potential for sexual reproduction in A. fumigatus and A. oryzae. Our analysis of sequence conservation revealed over 5,000 non-coding regions actively conserved across all three species. Within these regions, we identified potential functional elements including a previously uncharacterized TPP riboswitch and motifs suggesting regulation in filamentous fungi by Puf family genes. We further obtained comparative and experimental evidence indicating widespread translational regulation by upstream open reading frames. These results enhance our understanding of these widely studied fungi as well as provide new insight into eukaryotic genome evolution and gene regulation.
TL;DR: In this paper, the authors show that the fraction of publicly traded industrial firms that pay dividends is high when retained earnings are a large portion of total equity (and of total assets) and falls to near zero when most equity is contributed rather than earned.
Abstract: Consistent with a lifecycle theory of dividends, the fraction of publicly traded industrial firms that pays dividends is high when retained earnings are a large portion of total equity (and of total assets) and falls to near zero when most equity is contributed rather than earned. We observe a highly significant relation between the decision to pay dividends and the earned/contributed capital mix, controlling for profitability, growth, firm size, leverage, cash balances, and dividend history, a relation that also holds for dividend initiations and omissions. In our regressions, the mix of earned/contributed capital has a quantitatively greater impact than measures of profitability and growth opportunities. We document a massive increase in firms with negative retained earnings (from 11.8% of industrials in 1978 to 50.2% in 2002). Controlling for the earned/contributed capital mix, firms with negative retained earnings show virtually no change in their propensity to pay dividends from the mid-1970s to 2002, while those whose earned equity makes them reasonable candidates to pay dividends have a propensity reduction that is twice the overall reduction in Fama and French (2001). All our evidence supports the lifecycle theory of dividends, in which a firm's stage in that cycle is well-proxied by its mix of internal and external capital.
TL;DR: Routine molecular screening of patients with colorectal adenocarcinoma for the Lynch syndrome identified mutations in patients and their family members that otherwise would not have been detected.
Abstract: Background Germ-line mutations in the mismatch-repair genes MLH1, MSH2, MSH6, and PMS2 lead to the development of the Lynch syndrome (hereditary nonpolyposis colorectal cancer), conferring a strong susceptibility to cancer. We assessed the frequency of such mutations in patients with colorectal cancer and examined strategies for molecular screening to identify patients with the syndrome. Methods Patients with a new diagnosis of colorectal adenocarcinoma at the major hospitals in metropolitan Columbus, Ohio, were eligible for the study. Genotyping of the tumor for microsatellite instability was the primary screening method. Among patients whose screening results were positive for microsatellite instability, we searched for germ-line mutations in the MLH1, MSH2, MSH6, and PMS2 genes with the use of immunohistochemical staining for mismatch-repair proteins, genomic sequencing, and deletion studies. Family members of carriers of the mutations were counseled, and those found to be at risk were offered mutation...
TL;DR: It is concluded that up-regulation of several miRs and regulation of KIT are involved in PTC pathogenesis, and that sequence changes in genes targeted by miRNAs can contribute to their regulation.
Abstract: Apart from alterations in the RET/PTC-RAS-BRAF pathway, comparatively little is known about the genetics of papillary thyroid carcinoma (PTC). We show that numerous microRNAs (miRNAs) are transcriptionally up-regulated in PTC tumors compared with unaffected thyroid tissue. A set of five miRNAs, including the three most up-regulated ones (miR-221, -222, and -146), distinguished unequivocally between PTC and normal thyroid. Additionally, miR-221 was up-regulated in unaffected thyroid tissue in several PTC patients, presumably an early event in carcinogenesis. Tumors in which the up-regulation (11- to 19-fold) of miR-221, -222, and -146 was strongest showed dramatic loss of KIT transcript and Kit protein. In 5 of 10 such cases, this down expression was associated with germline single-nucleotide changes in the two recognition sequences in KIT for these miRNAs. We conclude that up-regulation of several miRs and regulation of KIT are involved in PTC pathogenesis, and that sequence changes in genes targeted by miRNAs can contribute to their regulation.
University of Florida1, Duke University2, Harvard University3, University of Cincinnati4, University of Michigan5, Johns Hopkins University6, University of North Carolina at Chapel Hill7, University of California, Los Angeles8, University of Texas Southwestern Medical Center9, University of Minnesota10, Mayo Clinic11, Ohio State University12, Northwestern University13, University of Calgary14, University of Kentucky15, Cleveland Clinic16, Vanderbilt University17, University of Alabama18, Case Western Reserve University19, University of Washington20, University of California, San Francisco21, University of Wisconsin-Madison22
TL;DR: Therapy to reduce volume overload during hospitalization for heart failure led to marked improvement in signs and symptoms of elevated filling pressures with or without the PAC, which reached significance for the time trade-off at all time points after randomization.
Abstract: Context Pulmonary artery catheters (PACs) have been used to guide therapy in multiple settings, but recent studies have raised concerns that PACs may lead to increased mortality in hospitalized patients. Objective To determine whether PAC use is safe and improves clinical outcomes in patients hospitalized with severe symptomatic and recurrent heart failure. Design, setting, and participants The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) was a randomized controlled trial of 433 patients at 26 sites conducted from January 18, 2000, to November 17, 2003. Patients were assigned to receive therapy guided by clinical assessment and a PAC or clinical assessment alone. The target in both groups was resolution of clinical congestion, with additional PAC targets of a pulmonary capillary wedge pressure of 15 mm Hg and a right atrial pressure of 8 mm Hg. Medications were not specified, but inotrope use was explicitly discouraged. Main outcome measures The primary end point was days alive out of the hospital during the first 6 months, with secondary end points of exercise, quality of life, biochemical, and echocardiographic changes. Results Severity of illness was reflected by the following values: average left ventricular ejection fraction, 19%; systolic blood pressure, 106 mm Hg; sodium level, 137 mEq/L; urea nitrogen, 35 mg/dL (12.40 mmol/L); and creatinine, 1.5 mg/dL (132.6 micromol/L). Therapy in both groups led to substantial reduction in symptoms, jugular venous pressure, and edema. Use of the PAC did not significantly affect the primary end point of days alive and out of the hospital during the first 6 months (133 days vs 135 days; hazard ratio [HR], 1.00 [95% confidence interval {CI}, 0.82-1.21]; P = .99), mortality (43 patients [10%] vs 38 patients [9%]; odds ratio [OR], 1.26 [95% CI, 0.78-2.03]; P = .35), or the number of days hospitalized (8.7 vs 8.3; HR, 1.04 [95% CI, 0.86-1.27]; P = .67). In-hospital adverse events were more common among patients in the PAC group (47 [21.9%] vs 25 [11.5%]; P = .04). There were no deaths related to PAC use, and no difference for in-hospital plus 30-day mortality (10 [4.7%] vs 11 [5.0%]; OR, 0.97 [95% CI, 0.38-2.22]; P = .97). Exercise and quality of life end points improved in both groups with a trend toward greater improvement with the PAC, which reached significance for the time trade-off at all time points after randomization. Conclusions Therapy to reduce volume overload during hospitalization for heart failure led to marked improvement in signs and symptoms of elevated filling pressures with or without the PAC. Addition of the PAC to careful clinical assessment increased anticipated adverse events, but did not affect overall mortality and hospitalization. Future trials should test noninvasive assessments with specific treatment strategies that could be used to better tailor therapy for both survival time and survival quality as valued by patients.
TL;DR: For patients with coronary artery disease, the reduced rate of progression of atherosclerosis associated with intensive statin treatment, as compared with moderate statin Treatment, is significantly related to greater reductions in the levels of both atherogenic lipoproteins and CRP.
Abstract: background Recent trials have demonstrated better outcomes with intensive than with moderate statin treatment. Intensive treatment produced greater reductions in both low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP), suggesting a relationship between these two biomarkers and disease progression. methods We performed intravascular ultrasonography in 502 patients with angiographically documented coronary disease. Patients were randomly assigned to receive moderate treatment (40 mg of pravastatin orally per day) or intensive treatment (80 mg of atorvastatin orally per day). Ultrasonography was repeated after 18 months to measure the progression of atherosclerosis. Lipoprotein and CRP levels were measured at baseline and follow-up. results In the group as a whole, the mean LDL cholesterol level was reduced from 150.2 mg per deciliter (3.88 mmol per liter) at baseline to 94.5 mg per deciliter (2.44 mmol per liter) at 18 months (P<0.001), and the geometric mean CRP level decreased from 2.9 to 2.3 mg per liter (P<0.001). The correlation between the reduction in LDL cholesterol levels and that in CRP levels was weak but significant in the group as a whole (r=0.13, P=0.005), but not in either treatment group alone. In univariate analyses, the percent change in the levels of LDL cholesterol, CRP, apolipoprotein B-100, and non–high-density lipoprotein cholesterol were related to the rate of progression of atherosclerosis. After adjustment for the reduction in these lipid levels, the decrease in CRP levels was independently and significantly correlated with the rate of progression. Patients with reductions in both LDL cholesterol and CRP that were greater than the median had significantly slower rates of progression than patients with reductions in both biomarkers that were less than the median (P=0.001). conclusions For patients with coronary artery disease, the reduced rate of progression of atherosclerosis associated with intensive statin treatment, as compared with moderate statin treatment, is significantly related to greater reductions in the levels of both atherogenic lipoproteins and CRP.
TL;DR: It is shown that there are significant interindividual and interpopulation differences in the copy number of a segmental duplication encompassing the gene encoding CCL3L1, a potent human immunodeficiency virus–1 (HIV-1)–suppressive chemokine and ligand for the HIV coreceptor CCR5.
Abstract: Segmental duplications in the human genome are selectively enriched for genes involved in immunity, although the phenotypic consequences for host defense are unknown. We show that there are significant interindividual and interpopulation differences in the copy number of a segmental duplication encompassing the gene encoding CCL3L1 (MIP-1αP), a potent human immunodeficiency virus–1 (HIV-1)–suppressive chemokine and ligand for the HIV coreceptor CCR5. Possession of a CCL3L1 copy number lower than the population average is associated with markedly enhanced HIV/acquired immunodeficiency syndrome (AIDS) susceptibility. This susceptibility is even greater in individuals who also possess disease-accelerating CCR5 genotypes. This relationship between CCL3L1 dose and altered HIV/AIDS susceptibility points to a central role for CCL3L1 in HIV/AIDS pathogenesis and indicates that differences in the dose of immune response genes may constitute a genetic basis for variable responses to infectious diseases.
TL;DR: The affect misattributions procedure (AMP) was sensitive to normatively favorable and unfavorable evaluations, and the misattribution effect was strong at both fast and slow presentation rates.
Abstract: Misattributions people make about their own affective reactions can be used to measure attitudes implicitly. Combining the logic of projective tests with advances in priming research, the affect misattribution procedure (AMP) was sensitive to normatively favorable and unfavorable evaluations (Experiments 1-4), and the misattribution effect was strong at both fast and slow presentation rates (Experiments 3 and 4). Providing further evidence of validity, the AMP was strongly related to individual differences in self-reported political attitudes and voting intentions (Experiment 5). In the socially sensitive domain of racial attitudes, the AMP showed in-group bias for Black and White participants. AMP performance correlated with explicit racial attitudes, a relationship that was moderated by motivations to control prejudice (Experiment 6). Across studies, the task was unaffected by direct warnings to avoid bias. Advantages of the AMP include large effect sizes, high reliability, ease of use, and resistance to correction attempts.
TL;DR: In this paper, Zheng-Tse diversity-multiplexing tradeoff for delay-limited coherent fading channels consisting of N (half-duplex and single-antenna) partners and one cell site is investigated.
Abstract: We propose novel cooperative transmission protocols for delay-limited coherent fading channels consisting of N (half-duplex and single-antenna) partners and one cell site In our work, we differentiate between the relay, cooperative broadcast (down-link), and cooperative multiple-access (CMA) (up-link) channels The proposed protocols are evaluated using Zheng-Tse diversity-multiplexing tradeoff For the relay channel, we investigate two classes of cooperation schemes; namely, amplify and forward (AF) protocols and decode and forward (DF) protocols For the first class, we establish an upper bound on the achievable diversity-multiplexing tradeoff with a single relay We then construct a new AF protocol that achieves this upper bound The proposed algorithm is then extended to the general case with (N-1) relays where it is shown to outperform the space-time coded protocol of Laneman and Wornell without requiring decoding/encoding at the relays For the class of DF protocols, we develop a dynamic decode and forward (DDF) protocol that achieves the optimal tradeoff for multiplexing gains 0lesrles1/N Furthermore, with a single relay, the DDF protocol is shown to dominate the class of AF protocols for all multiplexing gains The superiority of the DDF protocol is shown to be more significant in the cooperative broadcast channel The situation is reversed in the CMA channel where we propose a new AF protocol that achieves the optimal tradeoff for all multiplexing gains A distinguishing feature of the proposed protocols in the three scenarios is that they do not rely on orthogonal subspaces, allowing for a more efficient use of resources In fact, using our results one can argue that the suboptimality of previously proposed protocols stems from their use of orthogonal subspaces rather than the half-duplex constraint
TL;DR: In this article, the authors proposed a method to improve the soil organic carbon (SOC) stock through afforestation of agricultural soils and management of forest plantations through C sequestration, and the rate of SOC sequestration and the magnitude and quality of soil C stock depend on the complex interaction between climate, soils, tree species and management.
Princeton University1, University of Washington2, Apache Corporation3, Massachusetts Institute of Technology4, University of Tokyo5, Fermilab6, University of Sussex7, Institute of Cosmology and Gravitation, University of Portsmouth8, Pennsylvania State University9, University of Pennsylvania10, Ohio State University11, University of Chicago12
TL;DR: In this article, the authors combine the constraints from the recent Ly$\ensuremath{\alpha}$ forest analysis of the Sloan Digital Sky Survey (SDSS) and the SDSS galaxy bias analysis with previous constraints from sDSS galaxies clustering, the latest supernovae, and 1st year WMAP cosmic microwave background anisotropies, and find significant improvements on all of the cosmological parameters compared to previous constraints.
Abstract: We combine the constraints from the recent Ly$\ensuremath{\alpha}$ forest analysis of the Sloan Digital Sky Survey (SDSS) and the SDSS galaxy bias analysis with previous constraints from SDSS galaxy clustering, the latest supernovae, and 1st year WMAP cosmic microwave background anisotropies. We find significant improvements on all of the cosmological parameters compared to previous constraints, which highlights the importance of combining Ly$\ensuremath{\alpha}$ forest constraints with other probes. Combining WMAP and the Ly$\ensuremath{\alpha}$ forest we find for the primordial slope ${n}_{s}=0.98\ifmmode\pm\else\textpm\fi{}0.02$. We see no evidence of running, $dn/d\mathrm{ln} k=\ensuremath{-}0.003\ifmmode\pm\else\textpm\fi{}0.010$, a factor of $3$ improvement over previous constraints. We also find no evidence of tensors, $rl0.36$ ($95%$ c.l.). Inflationary models predict the absence of running and many among them satisfy these constraints, particularly negative curvature models such as those based on spontaneous symmetry breaking. A positive correlation between tensors and primordial slope disfavors chaotic inflation-type models with steep slopes: while the $V\ensuremath{\propto}{\ensuremath{\phi}}^{2}$ model is within the 2-sigma contour, $V\ensuremath{\propto}{\ensuremath{\phi}}^{4}$ is outside the 3-sigma contour. For the amplitude we find ${\ensuremath{\sigma}}_{8}=0.90\ifmmode\pm\else\textpm\fi{}0.03$ from the Ly$\ensuremath{\alpha}$ forest and WMAP alone. We find no evidence of neutrino mass: for the case of $3$ massive neutrino families with an inflationary prior, $\ensuremath{\sum}_{}^{}{m}_{\ensuremath{
u}}l0.42$ eV and the mass of lightest neutrino is ${m}_{1}l0.13$ eV at $95%$ c.l. For the 3 massless $+1$ massive neutrino case we find ${m}_{\ensuremath{
u}}l0.79$ eV for the massive neutrino, excluding at $95%$ c.l. all neutrino mass solutions compatible with the LSND results. We explore dark energy constraints in models with a fairly general time dependence of dark energy equation of state, finding ${\ensuremath{\Omega}}_{\ensuremath{\lambda}}=0.72\ifmmode\pm\else\textpm\fi{}0.02$, $\mathrm{w}(z=0.3)=\ensuremath{-}{0.98}_{\ensuremath{-}0.12}^{+0.10}$, the latter changing to $\mathrm{w}(z=0.3)=\ensuremath{-}{0.92}_{\ensuremath{-}0.10}^{+0.09}$ if tensors are allowed. We find no evidence for variation of the equation of state with redshift, $\mathrm{w}(z=1)=\ensuremath{-}{1.03}_{\ensuremath{-}0.28}^{+0.21}$. These results rely on the current understanding of the Ly$\ensuremath{\alpha}$ forest and other probes, which need to be explored further both observationally and theoretically, but extensive tests reveal no evidence of inconsistency among different data sets used here.
TL;DR: In this paper, the authors give an elementary review of black holes in string theory and discuss BPS holes, the microscopic computation of entropy and the ''fuzzball'' picture of the black hole interior suggested by microstates of the 2-charge system.
Abstract: We give an elementary review of black holes in string theory. We discuss BPS holes, the microscopic computation of entropy and the `fuzzball' picture of the black hole interior suggested by microstates of the 2-charge system.
TL;DR: In this article, the Spitzer Space Telescope mid-infrared colors, derived from the IRAC Shallow Survey, of nearly 10,000 spectroscopically identified sources from the AGN and Galaxy Evolution Survey, were used to identify active galaxies.
Abstract: Mid-infrared photometry provides a robust technique for identifying active galaxies. While the ultraviolet to mid-infrared (λ 5 μm) continuum of stellar populations is dominated by the composite blackbody curve and peaks at approximately 1.6 μm, the ultraviolet to mid-infrared continuum of active galactic nuclei (AGNs) is dominated by a power law. Consequently, with a sufficient wavelength baseline, one can easily distinguish AGNs from stellar populations. Mirroring the tendency of AGNs to be bluer than galaxies in the ultraviolet, where galaxies (and stars) sample the blue, rising portion of stellar spectra, AGNs tend to be redder than galaxies in the mid-infrared, where galaxies sample the red, falling portion of the stellar spectra. We report on Spitzer Space Telescope mid-infrared colors, derived from the IRAC Shallow Survey, of nearly 10,000 spectroscopically identified sources from the AGN and Galaxy Evolution Survey. On the basis of this spectroscopic sample, we find that simple mid-infrared color criteria provide remarkably robust separation of active galaxies from normal galaxies and Galactic stars, with over 80% completeness and less than 20% contamination. Considering only broad-lined AGNs, these mid-infrared color criteria identify over 90% of spectroscopically identified quasars and Seyfert 1 galaxies. Applying these color criteria to the full imaging data set, we discuss the implied surface density of AGNs and find evidence for a large population of optically obscured active galaxies.
TL;DR: In this article, different components of a multiphase transport (AMPT) model that uses the heavy ion jet interaction generator (HIJING) for generating the initial conditions, Zhang's parton cascade (ZPC) for modeling partonic scatterings, the Lund string fragmentation model or a quark coalescence model for hadronization, and a relativistic transport (ART) model for treating hadronic scatterings are improved and combined to give a coherent description of the dynamics of relativist heavy ion collisions.
Abstract: We describe in detail how the different components of a multiphase transport (AMPT) model that uses the heavy ion jet interaction generator (HIJING) for generating the initial conditions, Zhang's parton cascade (ZPC) for modeling partonic scatterings, the Lund string fragmentation model or a quark coalescence model for hadronization, and a relativistic transport (ART) model for treating hadronic scatterings are improved and combined to give a coherent description of the dynamics of relativistic heavy ion collisions. We also explain the way parameters in the model are determined and discuss the sensitivity of predicted results to physical input in the model. Comparisons of these results to experimental data, mainly from heavy ion collisions at the BNL Relativistic Heavy Ion Collider, are then made in order to extract information on the properties of the hot dense matter formed in these collisions.