431 research outputs found
Estimation of suspended sediment concentration by acoustic equations for soil sediment
The acoustic backscattering systems, ABS, for sediment measurement are based on the determining of the backscattering and attenuation properties of the particles in suspension. The relevant acoustic quantities are the form function, f, which describes the backscattering characteristics, and thenormalized total scattering cross-section, , which describes the attenuating characteristics of the particles in suspension. Formulations are required for these parameters of suspension sediment particles with size and acoustic frequency. Several studies have been conducted to determine theconcentration of sediments such as glass spheres or sand. However, the acoustic properties of natural sediments vary and depend on many parameters such as particle size, shape, mineralogy and distribution of those parameters in sample. Therefore, this study was conducted to determine the possibility of soil sediment concentration with the f and equations, which were obtained for glass spheres and sandy sediments under laboratory and river conditions. The results show that theacoustic method, especially with glass scattering equation, works fairly well to calculate soil sediment for low concentration range at laboratory and river conditions
How Generational Preferences, Cultural Trends, Workplace Expectations, and Other Factors Have Changed the Definition of Professionalism in Terms of Attire and How Employers and Managers Can Respond
Business attire is an essential part of personal branding as well as corporate branding activities. Fashion, cultural trends, workplace expectations play a role, among others form and change what an acceptable work attire is. Corporations even use their definitions of work attire in their advertising activities as a part of identity development. Such recent examples are State Farm Insurance, Progressive, and Enterprise Rent a Car. Observations during career development activities at multiple universities also revealed that Millennials might have different professional attire interpretations.
The literature review indicated a gap regarding how perceptions change from generation to generation in this topic. In the paper, factors that may influence the definition of professional attire have been investigated for three groups of respondents, including early career, mid-career, and retired professionals. Grounded Theory methodology has been used. Multiple themes have been identified for the three generational groups. Further research implications have been discussed
Commutator subgroups of the power subgroups of generalized Hecke groups
Let p, q ≥ 2 be relatively prime integers and let Hp,q be the generalized Hecke group associated to p and q. The generalized Hecke group Hp,q is generated by X(z) = −(z − λp)⁻¹ and Y (z) = −(z + λq)⁻¹ where λp = 2cos π/p and λq = 2 cos π/q.In this paper, for positive integer m, we study the commutator subgroups (Hᵐp,q)′ of the power subgroups Hᵐp,q of generalized Hecke groups Hp,q. We give an application related with the derived series for all triangle groups of the form (0; p, q, n), for distinct primes p, q and for positive integer n
Unlocking the Secrets of Al-tobermorite in Roman Seawater Concrete
Ancient Roman syntheses of Al-tobermorite in a 2000-year-old concrete block submerged in the Bay of Pozzuoli (Baianus Sinus), near Naples, have unique aluminum-rich and silica-poor compositions relative to hydrothermal geological occurrences. In relict lime clasts, the crystals have calcium contents that are similar to ideal tobermorite, 33 to 35 wt%, but the low-silica contents, 39 to 40 wt%, reflect Al3+ substitution for Si4+ in Q2 (1Al), Q3 (1Al), and Q3 (2 Al) tetrahedral chain and branching sites. The Al-tobermorite has a double silicate chain structure with long chain lengths in the b [020] crystallographic direction, and wide interlayer spacing, 11.49 Å. Na+ and K+ partially balance Al3+ substitution for Si4+. Poorly crystalline calcium-aluminum-silicate-hydrate (C-A-S-H) cementitious binder in the dissolved perimeter of relict lime clasts has Ca/(Si+Al) = 0.79, nearly identical to the Al-tobermorite, but nanoscale heterogeneities with aluminum in both tetrahedral and octahedral coordination. The concrete is about 45 vol% glassy zeolitic tuff and 55 vol% hydrated lime-volcanic ash mortar; lime formed wt% of the mix. Trace element studies confirm that the pyroclastic rock comes from Flegrean Fields volcanic district, as described in ancient Roman texts. An adiabatic thermal model of the 10 m2 by 5.7 m thick Baianus Sinus breakwater from heat evolved through hydration of lime and formation of C-A-S-H suggests maximum temperatures of 85 to 97 °C. Cooling to seawater temperatures occurred in two years. These elevated temperatures and the mineralizing effects of seawater and alkali- and alumina-rich volcanic ash appear to be critical to Al-tobermorite crystallization. The long-term stability of the Al-tobermorite provides a valuable context to improve future syntheses in innovative concretes with advanced properties using volcanic pozzolans
A cyclic nucleotide-gated channel (CNGC16) in pollen is critical for stress tolerance in pollen reproductive development
Cyclic nucleotide-gated channels (CNGCs) have been implicated in diverse aspects of plant growth and development, including responses to biotic and abiotic stress, as well as pollen tube growth and fertility. Here, genetic evidence identifies CNGC16 in Arabidopsis (Arabidopsis thaliana) as critical for pollen fertility under conditions of heat stress and drought. Two independent transfer DNA disruptions of cngc16 resulted in a greater than 10-fold stress-dependent reduction in pollen fitness and seed set. This phenotype was fully rescued through pollen expression of a CNGC16 transgene, indicating that cngc16-1 and 16-2 were both loss-of-function null alleles. The most stress-sensitive period for cngc16 pollen was during germination and the initiation of pollen tube tip growth. Pollen viability assays indicate that mutant pollen are also hypersensitive to external calcium chloride, a phenomenon analogous to calcium chloride hypersensitivities observed in other cngc mutants. A heat stress was found to increase concentrations of 3′,5′-cyclic guanyl monophosphate in both pollen and leaves, as detected using an antibody-binding assay. A quantitative PCR analysis indicates that cngc16 mutant pollen have attenuated expression of several heat-stress response genes, including two heat shock transcription factor genes, HsfA2 and HsfB1. Together, these results provide evidence for a heat stress response pathway in pollen that connects a cyclic nucleotide signal, a Ca(2+)-permeable ion channel, and a signaling network that activates a downstream transcriptional heat shock response
Cardiovascular outcomes in breast cancer survivors:a systematic review and meta-analysis
Aims It is unclear whether the future risk of cardiovascular events in breast cancer (BC) survivors is greater than in the general population. This meta-analysis quantifies the risk of cardiovascular disease development in BC patients, compared to the risk in a general matched cancer-free population, and reports the incidence of cardiovascular events in patients with BC.Methods and results We searched PubMed, Scopus, and Web of Science databases (up to 23 March 2022) for observational studies and post hoc analyses of randomized controlled trials. Cardiovascular death, heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), myocardial infarction (MI), and stroke were the individual endpoints for our meta-analysis. We pooled incidence rates (IRs) and risk in hazard ratios (HRs), using random-effects meta-analyses. Heterogeneity was reported through the I 2 statistic, and publication bias was examined using funnel plots and Egger’s test in the meta-analysis of risk. One hundred and forty-two studies were identified in total, 26 (836 301 patients) relevant to the relative risk and 116 (2 111 882 patients) relevant to IRs. Compared to matched cancer-free controls, BC patients had higher risk for cardiovascular death within 5 years of cancer diagnosis [HR = 1.09; 95% confidence interval (CI): 1.07, 1.11], HF within 10 years (HR = 1.21; 95% CI: 1.1, 1.33), and AF within 3 years (HR = 1.13; 95% CI: 1.05, 1.21). The pooled IR for cardiovascular death was 1.73 (95% CI 1.18, 2.53), 4.44 (95% CI 3.33, 5.92) for HF, 4.29 (95% CI 3.09, 5.94) for CAD, 1.98 (95% CI 1.24, 3.16) for MI, 4.33 (95% CI 2.97, 6.30) for stroke of any type, and 2.64 (95% CI 2.97, 6.30) for ischaemic stroke.Conclusion Breast cancer exposure was associated with the increased risk for cardiovascular death, HF, and AF. The pooled incidence for cardiovascular endpoints varied depending on population characteristics and endpoint studied.</p
Direct venous inoculation of Plasmodium falciparum sporozoites for controlled human malaria infection: a dose-finding trial in two centres
BACKGROUND: Controlled human malaria infection (CHMI)
accelerates development of anti-malarial interventions. So far,
CHMI is done by exposure of volunteers to bites of five
mosquitoes carrying Plasmodium falciparum sporozoites (PfSPZ), a
technique available in only a few centres worldwide.
Mosquito-mediated CHMI is logistically complex, exact PfSPZ
dosage is impossible and live mosquito-based interventions are
not suitable for further clinical development. METHODS: An
open-labelled, randomized, dose-finding study in 18-45 year old,
healthy, malaria-naive volunteers was performed to assess if
intravenous (IV) injection of 50 to 3,200 aseptic, purified,
cryopreserved PfSPZ is safe and achieves infection kinetics
comparable to published data of mosquito-mediated CHMI. An
independent study site verified the fully infectious dose using
direct venous inoculation of PfSPZ. Parasite kinetics were
assessed by thick blood smear microscopy and quantitative real
time PCR. RESULTS: IV inoculation with 50, 200, 800, or 3,200
PfSPZ led to parasitaemia in 1/3, 1/3, 7/9, and 9/9 volunteers,
respectively. The geometric mean pre-patent period (GMPPP) was
11.2 days (range 10.5-12.5) in the 3,200 PfSPZ IV group.
Subsequently, six volunteers received 3,200 PfSPZ by direct
venous inoculation at an independent investigational site. All
six developed parasitaemia (GMPPP: 11.4 days, range: 10.4-12.3).
Inoculation of PfSPZ was safe. Infection rate and pre-patent
period depended on dose, and injection of 3,200 PfSPZ led to a
GMPPP similar to CHMI with five PfSPZ-infected mosquitoes. The
infectious dose of PfSPZ predicted dosage of
radiation-attenuated PfSPZ required for successful vaccination.
CONCLUSIONS: IV inoculation of PfSPZ is safe, well tolerated and
highly reproducible. It shall further accelerate development of
anti-malarial interventions through standardization and
facilitation of CHMI. Beyond this, rational dose selection for
whole PfSPZ-based immunization and complex study designs are now
possible. TRIAL REGISTRATION: ClinicalTrials.gov NCT01624961 and
NCT01771848
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