Time-optimal control of two-level quantum systems by piecewise constant pulses

We apply an extension of the Pontryagin Maximum Principle to derive time-optimal controls of two-level quantum systems by means of piecewise constant pulses. Global optimal solutions are obtained for state-to-state transfer in the cases with one and two controls. Exact quantum speed limits are established as a function of the sampling period. We observe numerically an exponential convergence towards the minimum time in the continuous limit when this period goes to zero. We show that this convergence is only polynomial for a linearized quantum system. We discuss the experimental impact of this result.Comment: 28 pages, 9 figure

Occurrence and Fate of Antibiotics as Trace Contaminants in Wastewater Collection and Disposal Systems - Case Study: University of Dar es Salaam Wastewater Stabilization Ponds, in Tanzania

Antibacterial agents (Antibiotics) are emerging micro-contaminants in institutional and municipal wastewater and the aquatic environment. These substances enter wastewater effluents via urine and faeces and by improper disposal of domestic and or medical waste. An environmental analytical study was conducted at the University of Dar es Salaam (UDSM) Waste Stabilization Ponds (WSP). These ponds  receives and treats influents from students’ halls of residence and staff quarters (domestic effluents) as well as hospital effluent sources. The study focused on seven (7) antibiotics commonly used in human therapy, which include Ciprofloxacin, Flucloxacillin, Erythromycin, Ampicillin, Penicillin-V, Amoxycillin and Cloxacillin. In hospital wastewater, the detected antibiotics ranged from 0.98 - 7.10 µg/l, while in student’s halls of residence, the range was 0.2- 1.47μg/l. In WSP influent and effluent concentrations ranged from 8.89 to 63.75µg/l and 1.51 to 28.01µg/l, respectively. The concentration in the sewage sludge was from 72.12 to 370µg/l. Results of this study indicated that significant amount of antibiotics remain in the treatment plants during wastewater treatment process, through sorption to sewage sludge. This suggests that wastewater treatment options currently applicable in Tanzania including different sanitation options should now be designed taking into account the presence of trace concentrations of antibiotics for the purpose of sanitation and environmental protection at large. Keywords: Antibacterial Agents and Wastewater Stabilization Ponds

The Mechanism of Aromatization of 7-Norbornadiene Acetals. Evidence for Norcaradiene Formation

Dicarbomethoxy-tetraehloronorbornadienone aeetal le rearranges spontaneously to hemimelitate 3c while the corresponding anhydride 14 is stable up to 200oC. This result supports the hypothesis that the thermal rearrangement of substituted norbornadienes to aromatic products occurs by rate determining formation of norcaradiene intermediates

Secondary Deuterium Isotope Effects and Neighboring Group Participation Revisited

Studies on solvolytic reactions proceeding via neighboring group participation by means of secondary deuterium isotope effects are reviewed. The changes in magnitude of secondary KIEs are related to the degree of participation in the reaction transition state and these data are compared with other experimental evidence. Supporting information on the structure of carbocations is obtained by high level ab initio calculations. Isotope effect studies turned out to be among the most powerful tools available to chemists for elucidating the nature and structure of reaction transition states. »For progress there is no cure« J. von Neumann, 195

The minimal supersymmetric model without a mu term

We propose a supersymmetric extension of the standard model which is a realistic alternative to the MSSM, and which has several advantages. No 'mu' supersymmetric Higgs/Higgsino mass parameter is needed for sufficiently heavy harginos. An approximate U(1)(R) symmetry naturally guarantees that tan beta is large, explaining the top/bottom quark mass hierarchy. This symmetry also suppresses supersymmetric contributions to anomalous magnetic moments, b --> sgamma, and proton decay, and these processes place no lower bounds on superpartner masses, even at large tan beta. The soft supersymmetry breaking mass parameters can easily be obtained from either gauge or Planck scale mediation, without the usual mu problem. Unlike in the MSSM, there are significant upper bounds on the masses of superpartners, including an upper bound of 114 GeV on the mass of the lightest chargino. However the MSSM bound on the lightest Higgs mass does not apply

Allylic Cations in Solvolysis. A Case of Non-Participation

The rate constants and secondary deuterium Isotope ef\u27fects are measured in the solvo\u27lysis of various allyHc p-nitrobenzoates. The obtained results are explained by differences in inductive effects o>f vardous groups in the side-chain. These results are in keeping with the stepwise mechanism according to which neighboiring group n- and n-paxticiipation is not revealed in the studied solvCJ!lytic reactions

Magma emission rates fromshallow submarine eruptions using airborne thermal imaging

The effusion rate is the most important parameter to gatherwhen a volcanic eruption occurs, because it controls the way inwhich a lava body grows, extends and expands, influencing its dimensional properties. Calculation of lava flow volume from thermal images collected by helicopter surveys has been largely used during the last decade for monitoring subaerial effusive eruptions. However, due to the depths where volcanic activity occurs, monitoring submarine volcanic eruptions is a very difficult task. The 2011–2012 submarine volcanic eruption at El Hierro, Canary Islands, has provided a unique and excellent opportunity to monitor eruptive processes occurring on the seabed. The use of a hand-held thermal camera during daily helicopter flights allowed us to estimate for the first time the daily and total erupted magma volumes from a submarine eruption. The volume of magma emitted during this eruption has been estimated at 300 Mm3, giving an average effusion rate of ~25 m3 s−1. Thermal imagery by helicopter proved to be a fast, inexpensive, safe and reliable technique of monitoring volcanic eruptions when they occur on the shallow seabed.This research was financially supported by the projects MAKAVOL (MAC/3/C161) from the European Union MAC 2007–2013 Transnational Cooperation Program as well as from the Cabildo Insular de Tenerife. We are also grateful to the staff of El Hierro airport (AENA) for providing logistical support.Published219-2255V. Sorveglianza vulcanica ed emergenzeJCR Journalrestricte

A neurodegenerative disease landscape of rare mutations in Colombia due to founder effects

Background The Colombian population, as well as those in other Latin American regions, arose from a recent tri-continental admixture among Native Americans, Spanish invaders, and enslaved Africans, all of whom passed through a population bottleneck due to widespread infectious diseases that left small isolated local settlements. As a result, the current population reflects multiple founder effects derived from diverse ancestries. Methods We characterized the role of admixture and founder effects on the origination of the mutational landscape that led to neurodegenerative disorders under these historical circumstances. Genomes from 900 Colombian individuals with Alzheimer’s disease (AD) [n = 376], frontotemporal lobar degeneration-motor neuron disease continuum (FTLD-MND) [n = 197], early-onset dementia not otherwise specified (EOD) [n = 73], and healthy participants [n = 254] were analyzed. We examined their global and local ancestry proportions and screened this cohort for deleterious variants in disease-causing and risk-conferring genes. Results We identified 21 pathogenic variants in AD-FTLD related genes, and PSEN1 harbored the majority (11 pathogenic variants). Variants were identified from all three continental ancestries. TREM2 heterozygous and homozygous variants were the most common among AD risk genes (102 carriers), a point of interest because the disease risk conferred by these variants differed according to ancestry. Several gene variants that have a known association with MND in European populations had FTLD phenotypes on a Native American haplotype. Consistent with founder effects, identity by descent among carriers of the same variant was frequent. Conclusions Colombian demography with multiple mini-bottlenecks probably enhanced the detection of founder events and left a proportionally higher frequency of rare variants derived from the ancestral populations. These findings demonstrate the role of genomically defined ancestry in phenotypic disease expression, a phenotypic range of different rare mutations in the same gene, and further emphasize the importance of inclusiveness in genetic studies.Q2Q2Antecedentes La población colombiana, así como la de otras regiones latinoamericanas, surgió de una mezcla tricontinental reciente entre los nativos americanos, los invasores españoles y los africanos esclavizados, todos los cuales pasaron por un cuello de botella poblacional debido a enfermedades infecciosas generalizadas que dejaron a pequeños aislados. asentamientos locales. Como resultado, la población actual refleja múltiples efectos fundadores derivados de diversas ascendencias. Métodos Caracterizamos el papel de la mezcla y los efectos fundadores en el origen del paisaje mutacional que condujo a trastornos neurodegenerativos en estas circunstancias históricas. Genomas de 900 individuos colombianos con enfermedad de Alzheimer (EA) [n = 376], continuo degeneración lobar frontotemporal-enfermedad de la motoneurona (FTLD-MND) [n = 197], demencia de inicio temprano no especificada (EOD) [n = 73 ], y participantes sanos [n = 254] fueron analizados. Examinamos sus proporciones de ascendencia global y local y examinamos esta cohorte en busca de variantes nocivas en los genes que causan enfermedades y confieren riesgos. Resultados Identificamos 21 variantes patogénicas en genes relacionados con AD-FTLD, y PSEN1 albergaba la mayoría (11 variantes patogénicas). Se identificaron variantes de las tres ascendencias continentales. Las variantes heterocigotas y homocigotas de TREM2 fueron las más comunes entre los genes de riesgo de EA (102 portadores), un punto de interés porque el riesgo de enfermedad conferido por estas variantes difería según la ascendencia. Varias variantes genéticas que tienen una asociación conocida con MND en poblaciones europeas tenían fenotipos FTLD en un haplotipo nativo americano. De acuerdo con los efectos del fundador, la identidad por descendencia entre portadores de la misma variante fue frecuente. Conclusiones La demografía colombiana con múltiples mini-cuellos de botella probablemente mejoró la detección de eventos fundadores y dejó una frecuencia proporcionalmente más alta de variantes raras derivadas de las poblaciones ancestrales. Estos hallazgos demuestran el papel de la ascendencia definida genómicamente en la expresión fenotípica de la enfermedad, un rango fenotípico de diferentes mutaciones raras en el mismo gen, y enfatizan aún más la importancia de la inclusión en los estudios genéticos.https://orcid.org/0000-0001-6529-7077https://scholar.google.com/citations?hl=es&user=kaGongoAAAAJ&view_op=list_works&sortby=pubdatehttps://scienti.minciencias.gov.co/cvlac/visualizador/generarCurriculoCv.do?cod_rh=0000055000&lang=esRevista Internacional - Indexad

A neurodegenerative disease landscape of rare mutations in Colombia due to founder effects.

Background: The Colombian population, as well as those in other Latin American regions, arose from a recent tri-continental admixture among Native Americans, Spanish invaders, and enslaved Africans, all of whom passed through a population bottleneck due to widespread infectious diseases that left small isolated local settlements. As a result, the current population reflects multiple founder effects derived from diverse ancestries. Methods: We characterized the role of admixture and founder effects on the origination of the mutational landscape that led to neurodegenerative disorders under these historical circumstances. Genomes from 900 Colombian individuals with Alzheimer's disease (AD) [n = 376], frontotemporal lobar degeneration-motor neuron disease continuum (FTLD-MND) [n = 197], early-onset dementia not otherwise specified (EOD) [n = 73], and healthy participants [n = 254] were analyzed. We examined their global and local ancestry proportions and screened this cohort for deleterious variants in disease-causing and risk-conferring genes. Results: We identified 21 pathogenic variants in AD-FTLD related genes, and PSEN1 harbored the majority (11 pathogenic variants). Variants were identified from all three continental ancestries. TREM2 heterozygous and homozygous variants were the most common among AD risk genes (102 carriers), a point of interest because the disease risk conferred by these variants differed according to ancestry. Several gene variants that have a known association with MND in European populations had FTLD phenotypes on a Native American haplotype. Consistent with founder effects, identity by descent among carriers of the same variant was frequent. Conclusions: Colombian demography with multiple mini-bottlenecks probably enhanced the detection of founder events and left a proportionally higher frequency of rare variants derived from the ancestral populations. These findings demonstrate the role of genomically defined ancestry in phenotypic disease expression, a phenotypic range of different rare mutations in the same gene, and further emphasize the importance of inclusiveness in genetic studies