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Effective environmental policy often involves introducing and maintaining important activities with positive outcomes while minimizing environmental consequences; essentially decoupling a positive activity from its negative impacts. In-water cleaning (IWC) of biofouling from ships’ submerged surfaces is an example of an activity with positive outcomes (e.g., maintaining optimal ship energy efficiency and decreased biosecurity risk) and unintended negative consequences (e.g., release of living organisms, biocides, and microplastics). Several approaches exist to mitigate these negative consequences, including debris capture, with primary and secondary treatment of removed particulate and dissolved materials. However, it is unlikely that these approaches will eliminate environmental risk. Policy makers should be aware of the full suite of risks related to ship IWC and the tradeoffs to consider when balancing mitigation approaches.

Biofouling (including initial microbial biofilms) of submerged ship surfaces can directly impact vessel operations, leading to increases in fuel usage, greenhouse gas emissions, and the likelihood of non-indigenous species (NIS) transfer and impacts. Considerations of attainable and consistent biosecurity goals are paramount to the success of the widespread adoption of biofouling management policy. Proactive in-water cleaning (IWC) of biofilms from submerged ship surfaces may provide a viable option from a biosecurity and ship operations standpoint, however these benefits need to be balanced against other environmental costs, including the potential for increased biosecurity risks associated with the elevated release of diverse microbes from ship surfaces.

Microplastic pollution in the ocean is a critical, global environmental concern. Although believed to be a comparatively small contributor, the paints applied to commercial ships have been identified as a source of microplastics because polymers are used as binding agents in all anticorrosive and antifouling marine coatings. Furthermore, the release of microplastics from coatings may be amplified by in-water cleaning operations to remove biofouling. A comprehensive, detailed assessment and review of the array of commercial ships’ coatings, specifically characteristics, behavior, and fate over time, has not been conducted in the context of ocean microplastic pollution. This Policy Brief identifies gaps and proposes actions to better understand the fate of released particles with the goal to inform appropriate and effective solutions.

Synthetic aperture radar (SAR) systems employ a Linearly Chirped Microwave Waveform Generator (LCMWG) with large time–bandwidth product (TBWP), to provide a wide range resolution. Photonics has now been recognized as a disruptive approach to achieve high performance at bandwidth of few tens of gigahertz, with light and compact architectures, due to the typical photonics benefits, such as electromagnetic interference immunity, small power consumption, small footprint, and high immunity to vibration/shock and radiation. In this article, we report on the photonic generation of a high-frequency LCMW, with a large TBWP (102–103), using a chip-scaled architecture, based on a frequency-tunable optoelectronic oscillator (OEO) and a recirculating phase modulation loop (RPML). A new configuration of the OEO employing an ultrahigh Q-factor resonator has been conceived to allow the oscillator working in Ka band at 40 GHz or even more, with very low phase noise. Key building block of the RPML is a phase modulator driven by an engineered parabolic split waveform. The ultra-large pulse compression rate (PCR) >> 102, together with large signal purity, was also obtained, making the proposed architecture particularly suitable for SAR systems with large range resolution demand, such as Earth surveillance and monitoring.

Submerged ship surfaces are often inhabited by diverse sessile and sedentary marine organisms, which can directly impact vessel operations and increase the likelihood of non-indigenous species (NIS) establishment and impacts. Ship in-water cleaning (IWC) systems are now being incorporated into biofouling policy, and rigorous, transparent, and predictive verification testing is vital to regulatory success. Performance criteria for IWC approval should focus on environmental protection goals by including: qualified and independent testing; quantitative, robust, and statistically sound data, rather than qualitative observations; water sampling at all critical control points to characterize the release of harmful materials, including dissolved and particulate biocides; measurable and protective endpoints, rather than percent reductions; determinations of presence or absence of macro-organisms, irrespective of species origins or physiological state; and appropriately trained IWC operators.

Vessel biofouling is a major pathway for the introduction, establishment, and subsequent spread of marine non-indigenous macro-organisms. As a result, national and international regulations and guidelines have been implemented to manage the risks associated with this pathway, yet widespread enforcement and uptake are still in their infancy. By comparison, translocation of marine pathogens by vessel biofouling has received little attention despite a mounting body of evidence highlighting the potential importance of this pathway. Using molluscan pathogens as a model, this paper examines the potential for translocation of marine pathogens via the vessel biofouling pathway by reviewing: (1) examples where vessel biofouling is suspected to be the source pathway of non-indigenous pathogen introduction to new areas, and (2) the association between pathogens known to have detrimental effects on wild and farmed mollusk populations with species known to foul vessels and anthropogenic structures. The available evidence indicates that vessel biofouling is a viable and important pathway for translocating marine pathogens, presenting a risk to marine values (i.e., environmental, economic, social, and cultural). While preventive measures to minimize the translocation of macro-organisms are the most efficient way to minimize the likelihood of associated pathogen translocation, the application of reactive management measures to biofouled vessels, including post-filtration treatment, requires further and explicit consideration.

Biofouling is a long-standing challenge for ships because it can interfere with operations and increases vessel drag, fuel consumption and exhaust emissions. More recently, ship biofouling has also been recognized as a leading vector for global transfers and introductions of marine non-indigenous species. Ship in-water cleaning and capture (IWCC) systems, to remove and collect macrofouling organisms and associated antifouling coating compounds, are now becoming available as a possible solution to both problems. However, independent and rigorous evaluations of IWCC efficacy and environmental safety are needed to facilitate technology maturation, support vessel operator biofouling management decisions, aid IWCC approvals and permitting, and inform future biosecurity regulations. We developed a formal protocol for evaluating an IWCC system, on two ships with varying biofouling levels and under different environmental conditions, to quantify biofouling removal and capture efficacy as well as impacts on water quality. The IWCC system reduced hull biofouling by 82–94%. Concentrations of dissolved and particulate Cu and Zn in effluent from the IWCC onshore processing varied by orders of magnitude between trials, in one case greatly exceeding water quality standards. Our results demonstrate that rigorous, quantitative assessments of IWCC system performance are possible, even under challenging conditions. This initial evaluation also identifies the major factors that impact performance of in-water cleaning, and key needs for future research to consider in advancing standardized testing and independent evaluations needed for all in-water cleaning systems.

A hybrid titanium dioxide/silicon rich nitride ring resonator with the unique feature of being simultaneously athermal and polarization-insensitive is reported for the first time to our knowledge. Although its potential application domain is extremely wide, the designed integrated microphotonic cavity, having a racetrack shape, is intended for notch filtering in a microwave photonic passband filter. A careful selection of the CMOS-compatible material system and an innovative design approach have allowed a very low dependence of the filtering shape on the input beam polarization and, simultaneously, a thermal drift of the resonance wavelength 4, 4 nm, and 30.7 dB, respectively.

Context: Piqueria trinervia Cav. (Asteraceae) is a plant species with a long history in traditional medicine to cure diarrhoea and other digestive disorders. Objective: The study investigates the antigiardial activity of piquerol, trinervinol, red oil and two fractions (F1 and F2) from P. trinervia. Materials and methods: P. trinervia was collected in the Ajusco in Mexico City. Aerial parts were ground and mixed with water to obtain the extract, which was treated with dichloromethane to isolate piquerol and trinervinol (P & T). Remnants were the red oil, fractions 1 and 2 (RO, F1 & F2). Trophozoites of Giardia intestinalis were treated with P, T, RO, F1 and F2 at different concentrations (0.78–200 μg/mL) for 48 h. Antigiardial activity was measured using the methylene blue reduction, and the cytotoxicity assayed on human fibroblasts and Vero cells by reduction of tetrazolium salts. Results: Trinervinol and piquerol showed antigiardial activity with an IC50 = 2.03 and 2.42 μg/mL, and IC90 = 13.03 and 8.74 μg/mL, respectively. The concentrations of trinervinol (CC50 = 590 μg/mL) and piquerol (CC50 = 501 μg/mL) were not cytotoxic to human fibroblasts. Conclusions: Compounds from P. trinervia showed antigiardial activity; to enhance this activity, piquerol and trinervinol can be chemically modified.

Recurrent blooms of harmful algae and cyanobacteria (HABs) plague many coastal and inland waters throughout the United States and have significant socioeconomic impacts to the adjacent communities. Notable HAB events in recent years continue to underscore the many remaining gaps in knowledge and increased needs for technological advances leading to early detection. This review summarizes the main research and management priorities that can be addressed through ocean observation-based approaches and technological solutions for harmful algal blooms, provides an update to the state of the technology to detect HAB events based on recent activities of the Alliance for Coastal Technologies (ACT), offers considerations for ensuring data quality, and highlights both ongoing challenges and opportunities for solutions in integrating HAB-focused technologies in research and management. Specifically, technological advances are discussed for remote sensing (both multispectral satellite and hyperspectral); deployable in situ detection of HAB species on fixed or mobile platforms (based on bulk or taxa-specific biomass, images, or molecular approaches); and field-based and/or rapid quantitative detection of HAB toxins (via molecular and analytical chemistry methods). Suggestions for addressing challenges to continued development and adoption of new technologies are summarized, based on a consensus-building workshop hosted by ACT, including dealing with the uncertainties in investment for HAB research, monitoring, and management. Challenges associated with choosing appropriate technologies for a given ecosystem and/or management concern are also addressed, and examples of programs that are leveraging and combining complementary approaches are highlighted.

The oceans play a key role in global issues such as climate change, food security, and human health. Given their vast dimensions and internal complexity, efficient monitoring and predicting of the planet’s ocean must be a collaborative effort of both regional and global scale. A first and foremost requirement for such collaborative ocean observing is the need to follow well-defined and reproducible methods across activities: from strategies for structuring observing systems, sensor deployment and usage, and the generation of data and information products, to ethical and governance aspects when executing ocean observing. To meet the urgent, planet-wide challenges we face, methods across all aspects of ocean observing should be broadly adopted by the ocean community and, where appropriate, should evolve into “Ocean Best Practices.” While many groups have created best practices, they are scattered across the Web or buried in local repositories and many have yet to be digitized. To reduce this fragmentation, we introduce a new open access, permanent, digital repository of best practices documentation (oceanbestpractices.org) that is part of the Ocean Best Practices System (OBPS). The new OBPS provides an opportunity space for the centralized and coordinated improvement of ocean observing methods. The OBPS repository employs user-friendly software to significantly improve discovery and access to methods. The software includes advanced semantic technologies for search capabilities to enhance repository operations. In addition to the repository, the OBPS also includes a peer reviewed journal research topic, a forum for community discussion and a training activity for use of best practices. Together, these components serve to realize a core objective of the OBPS, which is to enable the ocean community to create superior methods for every activity in ocean observing from research to operations to applications that are agreed upon and broadly adopted across communities. Using selected ocean observing examples, we show how the OBPS supports this objective. This paper lays out a future vision of ocean best practices and how OBPS will contribute to improving ocean observing in the decade to come.

The design, fabrication, and optical characterization of the sensing element of a photonic InP-based gyroscope intended for applications in the field of aerospace and defense are reported in this paper. The sensing element is a spiral resonator coupled to a straight bus waveguide through a multimode interference coupler and exhibits a Q factor of approximately 600 000 with a footprint of approximately 10 mm 2. The design of each component of the sensor is based on some well-established numerical methods such as the Finite Element Method, the beam propagation method, and the film mode matching method. The spiral cavity was designed using the standard transfer matrix method. The selected fabrication process, which is an enhanced version of the standard COBRA process, allows the monolithic integration of the sensing element with the other active components of the gyroscope, e.g., lasers, photodiodes, and modulators. Each component of the fabricated sensing element was optically characterized using an appropriate setup, which was also used for the optical characterization of the whole sensor. Based on the results of the characterization, the gyro performance was evaluated, and a way to improve both the resolution and the bias drift, i.e., down to 10°/h and 1°/h, respectively, was also clearly identified. The achieved results demonstrate, for the first time, the actual feasibility of a photonic gyro-on-chip through a well-established InP-based generic integration process.

The ability to confine light at the nanoscale continues to excite the research community, with the ratio between quality factor Q and volume V, i.e., the Q/V ratio, being the key figure of merit. In order to achieve strong light-matter interaction, however, it is important to confine a lot of energy in the resonant cavity mode. Here, we demonstrate a novel cavity design that combines a photonic crystal nanobeam cavity with a plasmonic bowtie antenna. The nanobeam cavity is optimised for a good match with the antenna and provides a Q of 1700 and a transmission of 90%. Combined with the bowtie, the hybrid photonic-plasmonic cavity achieves a Q of 800 and a transmission of 20%, both of which remarkable achievements for a hybrid cavity. The ultra-high Q/V of the hybrid cavity is of order of 106 (λ/n)−3, which is comparable to the state-of-the-art of photonic resonant cavities. Based on the high Q/V and the high transmission, we demonstrate the strong efficiency of the hybrid cavity as a nanotweezer for optical trapping. We show that a stable trapping condition can be achieved for a single 200 nm Au bead for a duration of several minutes (ttrap > 5 min) and with very low optical power (Pin = 190 μW).

The development of phosphate sensors suitable for long-term in situ deployments in natural waters, is essential to improve our understanding of the distribution, fluxes, and biogeochemical role of this key nutrient in a changing ocean. Here, we describe the optimization of the molybdenum blue method for in situ work using a lab-on-chip (LOC) analyzer and evaluate its performance in the laboratory and at two contrasting field sites. The in situ performance of the LOC sensor is evaluated using hourly time-series data from a 56-day trial in Southampton Water (UK), as well as a month-long deployment in the subtropical oligotrophic waters of Kaneohe Bay (Hawaii, USA). In Kaneohe Bay, where phosphate concentrations were characteristic of the dry season (0.13 ± 0.03 μM, n = 704), the in situ sensor accuracy was 16 ± 12% and a potential diurnal cycle in phosphate concentrations was observed. In Southampton Water, the sensor data (1.02 ± 0.40 μM, n = 1,267) were accurate to ±0.10 μM relative to discrete reference samples. Hourly in situ monitoring revealed striking tidal and storm derived fluctuations in phosphate concentrations in Southampton Water that would not have been captured via discrete sampling. We show the impact of storms on phosphate concentrations in Southampton Water is modulated by the spring-neap tidal cycle and that the 10-fold decline in phosphate concentrations observed during the later stages of the deployment was consistent with the timing of a spring phytoplankton bloom in the English Channel. Under controlled laboratory conditions in a 250 L tank, the sensor demonstrated an accuracy and precision better than 10% irrespective of the salinity (0–30), turbidity (0–100 NTU), colored dissolved organic matter (CDOM) concentration (0–10 mg/L), and temperature (5–20°C) of the water (0.3–13 μM phosphate) being analyzed. This work demonstrates that the LOC technology is mature enough to quantify the influence of stochastic events on nutrient budgets and to elucidate the role of phosphate in regulating phytoplankton productivity and community composition in estuarine and coastal regimes.

El Instituto de Botánica Carlos Spegazzini (IBCS) (UNLP, La Plata) contiene un herbario de hongos (LPS) de aproximadamente 40000 ejemplares, con 4200 especies tipo. El objetivo de este trabajo fue examinar los ejemplares de hongos liquenizados depositados en el IBCS, actualizar su taxonomía y denominación, revisar las especies con determinación dudosa, identificar aquellos no determinados, e incorporarlos en el Herbario LPS. Se estudiaron 192 ejemplares de 11 provincias de Argentina y de Brasil, Uruguay y Francia y de se determinaron en base a su exo-morfología, cortes histológicos y reacciones histoquímicas. También se realizaron Cromatografías en Capa Delgada (TLC) para estudiar los metabolitos presentes. Se estableció la distribución geográfica en Argentina de las especies identificadas. Se corrigió el 91,66% de los materiales examinados (176 ejemplares), contabilizándose un total de 91 especies, 50 géneros y 21 familias, siendo las mejor representadas Parmeliaceae (16 géneros; 31 especies), Graphidaceae (4; 5) y Physciaceae (3; 9). Se actualizó la nominación de 56 ejemplares pertenecientes a 32 especies. Se modificó la identidad de 120 ejemplares, a nivel de especie (87), género (33) y familia (1). Se amplía la distribución en Argentina de 9 especies

This paper reports the numerical and experimental results of a high-Q silica-onsilicon spiral resonator to be used in microoptical gyroscopes having a potential resolution 2 waveguiding spiral cavity as sensing element for gyro applications is given, and results of its optical characterization are provided. Quality factor, finesse, free spectral range, and thermal stability have been measured, clearly showing the potential of the device for gyro applications. The effect of coupling tuning through micrometer scale heaters and the supported eigenstates of polarization have also been experimentally investigated. The thermal stabilization of the silica chip is realized using a thermoelectric cooler co-packaged with the resonant cavity. The Q-factor of the spiral exceeds 106, and the thermal drift of the resonance frequency is very low (

El objetivo del trabajo fue llevar a cabo un relevamiento de la carga fúngica ambiental y otros bioaerosoles asociados a un depósito de restos momificados del NOA del Museo de La Plata. Se realizaron dos tipos de monitoreos, i) uno del tipo aerobiológico (viable y no viable) en el aire exterior del depósito, en el aire interior del mismo y en el interior de 3 de sus vitrinas donde se hallan restos humanos; y ii) otro que consistió en el estudio y cultivo de la micobiota asociada a la superficie de materiales con signos evidentes de deterioro. En base al muestreo aerobiológico, se registró la mayor diversidad y concentración esporal en el ambiente exterior siendo Alternaria sp., Cladosporium cladosporioides y Penicillium sp. los taxa más representativos. Aunque el interior del depósito como de cada vitrina analizada mostró una carga fúngica particular, la abundancia de las esporas correspondientes a Aspergillus sp., Cladosporium sp. y Penicillium sp. fue característica. El análisis de las muestras de contacto evidenció la presencia de Cladosporium herbarum, Penicillium frequentans y Talaromyces helicus en asociación a las momias analizadas. El conocimiento de los hongos presentes en ambientes interiores y sobre materiales de valor patrimonial constituye un elemento clave para el establecimiento de pautas de control para su conservación.

A guided-wave chemical sensor for the detection of environmental pollutants or biochemical substances has been designed. The sensor is based on an asymmetric directional coupler employing slot optical waveguides. The use of a nanometer guiding structure where optical mode is confined in a low-index region permits a very compact sensor (device area about 1200 μm2) to be realized, having the minimum detectable refractive index change as low as 10-5. Silicon-on-Insulator technology has been assumed in sensor design and a very accurate modelling procedure based on Finite Element Method and Coupled Mode Theory has been pointed out. Sensor design and optimization have allowed a very good trade-off between device length and sensitivity. Expected device sensitivity to glucose concentration change in an aqueous solution is of the order of 0.1 g/L.

Este trabalho foi desenvolvido com o objetivo de ajustar equações que estimam a perda distribuída de carga em microtubos utilizados em microaspersão e a perda localizada de carga na passagem lateral do fluxo por meio dos conectores na linha lateral. A perda distribuída de carga foi determinada em quatro diâmetros de microtubos com nove a dez repetições para 15 vazões, por meio da aplicação do teorema de Bernoulli. O fator de atrito (f) foi estimado fixando-se o valor de m = 0,25 e calibrando-se o valor do parâmetro c (0,290). A perda localizada de carga foi determinada por diferença entre perda de carga no microtubo mais conector e perda de carga no microtubo. Dois modelos de conectores foram utilizados e caracterizados quanto ao diâmetro interno e dimensões. Uma aproximação matemática foi proposta para calcular a perda localizada de carga com base em coeficiente de carga cinética do conector (K'), que leva em consideração as dimensões do conector e do microtubo e independência das forças viscosas para Re > 5.000. As variações de vazão e de pressão entre os emissores situados nos extremos da linha lateral mostraram-se sensíveis à perda de carga na passagem lateral pelo conector mais a perda de carga no microtubo.This work was carried out aimed at presenting equations to estimate the continuous head loss in microtubes and the local head loss in the connector used on microsprinklers lateral lines. The continuous head loss was determined using Bernoulli's theorem for four microtubes diameters, each one with nine to ten replications for 15 flowrates. The Darcy-Weisbach friction factor was estimated by setting m to 0.25 and by calibrating the parameter value c to 0.290. The local head loss was determined by subtracting the head loss on the connector and microtube from the head loss on the microtube. Two types of connectors were used and characterized by its internal diameters and its dimensions. A mathematical approach to compute the local head loss was proposed based on a kinetic head connector coefficient (K'). This coefficient is a function of connector and microtube dimensions and independent of viscous forces up to Re > 5,000. Flowrate and pressure at emitters located at the far end of the lateral line were sensitive the head losses at the connectors and in the microtube.

OBJECTIVE: To identify factors related to cases of low birth weight among a sample of Mexican women. MATERIAL AND METHODS: The present analysis utilizes data from a post partum survey of 565 women implemented in eight different social security hospitals in western Mexico during 2001. Women giving birth to low weight infants (2.5 kgs) were oversampled and make up half of the sample. RESULTS: A series of logistic regression equations are presented that estimate the risk of low birth weight. Study findings indicate that, although behavioral factors appear to be highly significant in predicting the odds of low birth weight, socioeconomic and sociodemographic factors were found to be important in determining utilization of prenatal care. CONCLUSIONS: The key role of behavioral characteristics in determining low birth weight risk and the role of socioeconomic and sociodemographic factors in determining prenatal care usage highlights the need to improve prenatal care utilization by disadvantaged populations.OBJETIVO: Objetivo. Identificar los factores relacionados con el bajo peso al nacer en mujeres mexicanas. MATERIAL Y MÉTODOS: Se analizan datos de una encuesta recientemente aplicada en 2001 a 565 mujeres en condición de posparto, en ocho hospitales de la Secretaría de Salud, en el Occidente de la República Mexicana, que permite una evaluación detallada de los factores que contribuyen al riesgo de bajo peso. La mitad de las mujeres había dado a luz a recién nacidos de bajo peso (menos de 2.5 kgs) y el resto de peso normal. Este trabajo presenta los resultados de una serie de regresiones logísticas que estiman el riesgo de bajo peso al nacer. RESULTADOS: Los resultados indican que mientras los factores de comportamiento están asociados significativamente al bajo peso al nacer, los factores sociodemográficos y socioeconómicos están más relacionados con la utilización de servicios de atención prenatal. CONCLUSIONES: El papel clave de las características de comportamiento en la determinación del riesgo del bajo peso y el papel de los factores sociodemográficos y socioeconómicos en la determinación de atención prenatal, enfatizan la necesidad de incrementar la utilización de servicios de atención prenatal por parte de los sectores más desfavorecidos de la población.

Objetivo. Analizar la situación de los derechos humanos en las normas sobre el VIH/SIDA de México y Centroamérica en el periodo de 1993 a 2000. Material y métodos. Se analizó el contenido de las leyes y normas de la Región relacionadas con la prevención y control del VIH/SIDA. Se tomó como referencia una visión constructivista de los subsistemas jurídicos y de los derechos humanos. Se elaboraron categorías de análisis basadas en la Declaración Universal de los Derechos Humanos y a cada una se le asignaron códigos de significado. Resultados. Durante el periodo se observó una intensa actividad legislativa sobre el control de la transmisión del VIH/SIDA en la Región donde el tema de los derechos humanos fue incorporado. Sin embargo, en algunos casos (la Ley de Panamá y la Propuesta de Honduras) contienen apartados que lesionan el derecho a la no discriminación y a la privacidad. Ello marca dos vertientes: una, que garantiza totalmente los derechos humanos, y otra, que se convierte en un contexto que puede volver aún más vulnerables a ciertos grupos. Discusión. Se centra en proponer una resignificación del sujeto social y de la vigilancia epidemiológica con base en una normatividad que incluya el tema de los derechos humanos.Objective. To analyze the inclusion of human rights in HIV/AIDS norms in Mexico and Central America for the 1993-2000 period. Material and Methods. Norms and regulations for HIV/AIDS prevention and control in this region were analyzed. A constructivist perspective of judiciary subsystems and human rights was used as a reference framework, to establish categories of analysis with significance codes based on the Universal Declaration of Human Rights. Results. During the study period, human rights were included within a vigorous legislative activity for HIV/AIDS transmission prevention. In some cases (as in the Panama Law and the Honduras Proposal) there were passages of law violating the right to non-discrimination and privacy. These laws lead to either of two conflicting paths: one ensuring human rights, and another increasing the vulnerability of some groups. Conclusions. The authors emphasize the importance of gaining a new understanding of social subjects and epidemiological surveillance, based on norms that incorporate human rights issues.

In general, the papers in this special issue focus on recent advances, including modeling, development, and fabrication strategies, as well as applications in strategic sectors, such as the case of safety and security field trials.

The demand for sustainable synthetic methods has motivated the development of a myriad of strategies for substrate oxidation chemistry that reflect the goals of green chemistry. Here we present a two-part laboratory module that provides undergraduate chemistry students hands-on experience with the concepts of sustainable chemistry in the context of C-N bond-forming chemistry. First, students perform a traditional Pd-catalyzed C-N cross-coupling reaction between an aryl halide and an amine (i.e., C-X/N-H coupling). In the second part, students investigate a hypervalent iodine-catalyzed reaction that uses O[subscript 2] as a terminal oxidant for direct C-H/N-H coupling. On the basis of these two methods for accessing the same arylated amine product, students evaluate aspects of sustainability qualitatively by discussing the 12 Principles of Green Chemistry and quantitatively via green chemistry metric pentagons. These investigations highlight the complex balance of variables that must be considered when evaluating the sustainability of chemical processes. Through these activities, students explore the concepts of aerobic oxidation, hypervalency, green chemistry, and organocatalysis, while enforcing laboratory skills such as Schlenk-line technique, gas handling, and NMR spectroscopy.

The goal of this study was to investigate the timing of online homework completion and its effects on student performance. Data was collected from two large, first-semester general chemistry sections at a southwestern university. Specifically, this study aims to explore the link between when students complete their homework relative to the date the material was covered in lecture and student performance in that class. Topics covered in the study included VSEPR, Lewis structures, and molecular geometry. Performance was measured by different variables, namely in-class clicker scores (short-term) and exam grade (long-term). Students were divided into three groups: students who completed the relevant homework within 2 days after the lecture (before the next lecture), those who completed the homework 2 to 4 days after the lecture, and students who completed the homework more than 4 days after the material was covered in lecture. The study also took into consideration student reasoning abilities, as measured by the Test of Logical Thinking (TOLT), with a focus on at-risk students (low TOLT students). Results showed promising findings for low TOLT students. Instructors can employ results from this study to help their students better utilize the online homework resources.