Measurement report: Introduction to the HyICE-2018 campaign for measurements of ice-nucleating particles and instrument inter-comparison in the Hyytiälä boreal forest

The formation of ice particles in Earth's atmosphere strongly influences the dynamics and optical properties of clouds and their impacts on the climate system. Ice formation in clouds is often triggered heterogeneously by ice-nucleating particles (INPs) that represent a very low number of particles in the atmosphere. To date, many sources of INPs, such as mineral and soil dust, have been investigated and identified in the low and mid latitudes. Although less is known about the sources of ice nucleation at high latitudes, efforts have been made to identify the sources of INPs in the Arctic and boreal environments. In this study, we investigate the INP emission potential from high-latitude boreal forests in the mixed-phase cloud regime. We introduce the HyICE-2018 measurement campaign conducted in the boreal forest of Hyytiälä, Finland, between February and June 2018. The campaign utilized the infrastructure of the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) II, with additional INP instruments, including the Portable Ice Nucleation Chamber I and II (PINC and PINCii), the SPectrometer for Ice Nuclei (SPIN), the Portable Ice Nucleation Experiment (PINE), the Ice Nucleation SpEctrometer of the Karlsruhe Institute of Technology (INSEKT) and the Microlitre Nucleation by Immersed Particle Instrument (µL-NIPI), used to quantify the INP concentrations and sources in the boreal environment. In this contribution, we describe the measurement infrastructure and operating procedures during HyICE-2018, and we report results from specific time periods where INP instruments were run in parallel for inter-comparison purposes. Our results show that the suite of instruments deployed during HyICE-2018 reports consistent results and therefore lays the foundation for forthcoming results to be considered holistically. In addition, we compare measured INP concentrations to INP parameterizations, and we observe good agreement with the Tobo et al. (2013) parameterization developed from measurements conducted in a ponderosa pine forest ecosystem in Colorado, USA

The study of atmospheric ice-nucleating particles via microfluidically generated droplets

Ice-nucleating particles (INPs) play a significant role in the climate and hydrological cycle by triggering ice formation in supercooled clouds, thereby causing precipitation and affecting cloud lifetimes and their radiative properties. However, despite their importance, INP often comprise only 1 in 10³–10⁶ ambient particles, making it difficult to ascertain and predict their type, source, and concentration. The typical techniques for quantifying INP concentrations tend to be highly labour-intensive, suffer from poor time resolution, or are limited in sensitivity to low concentrations. Here, we present the application of microfluidic devices to the study of atmospheric INPs via the simple and rapid production of monodisperse droplets and their subsequent freezing on a cold stage. This device offers the potential for the testing of INP concentrations in aqueous samples with high sensitivity and high counting statistics. Various INPs were tested for validation of the platform, including mineral dust and biological species, with results compared to literature values. We also describe a methodology for sampling atmospheric aerosol in a manner that minimises sampling biases and which is compatible with the microfluidic device. We present results for INP concentrations in air sampled during two field campaigns: (1) from a rural location in the UK and (2) during the UK’s annual Bonfire Night festival. These initial results will provide a route for deployment of the microfluidic platform for the study and quantification of INPs in upcoming field campaigns around the globe, while providing a benchmark for future lab-on-a-chip-based INP studies

Pulmonary Tuberculosis: Case Finding and Treatment Outcome at Ekpene Obom (Etinan) Control Center, Nigeria

Incidence of Tuberculosis (TB) and the outcome of treatment at the implementation of Directly Observed Treatment Short course (DOTS) among patients attending the TB clinic at Qua Iboe Church (QIC) Leprosy Hospital, Ekpene Obom, Etinan in Akwa Ibom State, Nigeria were studied. Of the 883 patients aged between 12 and 68 years who attended the clinic from January 2001 to December 2003, 550 (62.3%) pulmonary cases were smear positive for Acid Fast Bacilli (AFB), 48 (5.4%) had extra-pulmonary tuberculosis and 285 (32.3%) were smear negative. Of the 598 patients who were on prescribed treatment according to the DOTS regimen, 450 (75.3%) were fully cured on completion of their treatment schedule, 14 (2.3%) had failed treatment and 111 (18.6%) defaulted. However, within the duration of the study, 21 (3.5%) patients died while 2 (0.3%) were referred. There were significant increases in cure rates from 63.0% in 2001 to 87.2% in 2003 leading to a corresponding decrease in treatment failure rate from 3.9% in 2001 to 0.0% in 2003. The findings obtained from this study are highly suggestive of the effectiveness of DOTS in the control of tuberculosis and therefore emphasize the need for more treatment supervision and intensification of efforts geared towards continuous provision of adequate drugs and other infrastructures to avert the emergence of drug resistant TB in the community. Keywords: Pulmonary tuberculosis, DOTS, case finding Journal of Medical Laboratory Sciences Vol. 14 (2) 2005: pp.4

Productivity and Unemployment in Nigeria

Productivity and employment are issues that are central to the social and economic life of every country. The extant literature refers to productivity and unemployment as constituting a vicious circle that explains the endemic nature of poverty in developing countries. And it has been argued that continuous improvement in productivity is the surest way to breaking this vicious circle. Growth in productivity provides a significant basis for adequate supply of goods and services thereby improving the welfare of the people and enhancing social progress. As pointed out by Dernburg (1985:63), "Without it there would be no growth in per capita income, and inflation control would be all the more difficult". In fact, the observation has been made that continuous enhancement of productivity has been very central to the brilliant performance of the Asian Tigers and Japan in recent years (Simbeye, 1992; World Bank 1993). Recent developments in the world economy have also shown that countries with high productivity are not only central to the determination of global balance of powers (e.g Japan and Germany), but also serve as centres of stimulus, where world resources (including labour) are redirected to, as opposed to countries with low or declining productivity. Recent studies, for example, Rensburg and Nande (1999) and Roberts and Tybout (1997) have also shown that high productivity increases competitiveness in terms of penetrating the world market. Thus, a country with high productivity is often characterized by a very high capacity utilization (optimal use of resources), high standard of living, low rate of unemployment and social progress. Unemployment, on the other hand, has been categorized as one of the serious impediments to social progress. Apart from representing a colossal waste of a country's manpower resources, it generates welfare loss in terms of lower output thereby leading to lower income and well-being (Akinboyo, 1987; and Raheem, 1993). Unemployment is a very serious issue in Africa (Vandemoortele, 1991 and Rama, 1998) and particularly in Nigeria (Oladeji, 1994 and Umo, 1996). The need to avert the negative effects of unemployment has made the tackling of unemployment problems to feature very prominently in the development objectives of many developing countries. Incidentally, most of these countries' economies are also characterized by low productivity. Thus, it seems obvious to many policy makers that there must be a straight forward connection between productivity and employment/unemployment. However, the theoretical linkage between productivity and unemployment is yet to be settled in the literature. While some researchers posit that higher productivity may increase unemployment (e.g. Diachavbre, 1991; Krugman, 1994), some others argue that it could increase employment (e.g Yesufu, 1984; Akerele, 1994; CEC, 1993). In view of the unfolding reality coupled with the protracted debates this paper attempts to examine the linkage between productivity and unemployment. Specifically, it examines the dimensions of productivity and unemployment in Nigeria as well as the direction of causality between them. To this end, the rest of the paper is organized thus. Following this introduction is part II, which examines the conceptual and theoretical is sues. Part III discusses the profile of productivity and unemployment in Nigeria while the empirical link between them is examined in part IV. The final part contains the policy implications and conclusions

Synergistic HNO₃–H₂SO₄–NH₃ upper tropospheric particle formation

New particle formation in the upper free troposphere is a major global source of cloud condensation nuclei (CCN)1,2,3,4. However, the precursor vapours that drive the process are not well understood. With experiments performed under upper tropospheric conditions in the CERN CLOUD chamber, we show that nitric acid, sulfuric acid and ammonia form particles synergistically, at rates that are orders of magnitude faster than those from any two of the three components. The importance of this mechanism depends on the availability of ammonia, which was previously thought to be efficiently scavenged by cloud droplets during convection. However, surprisingly high concentrations of ammonia and ammonium nitrate have recently been observed in the upper troposphere over the Asian monsoon region5,6. Once particles have formed, co-condensation of ammonia and abundant nitric acid alone is sufficient to drive rapid growth to CCN sizes with only trace sulfate. Moreover, our measurements show that these CCN are also highly efficient ice nucleating particles—comparable to desert dust. Our model simulations confirm that ammonia is efficiently convected aloft during the Asian monsoon, driving rapid, multi-acid HNO3–H2SO4–NH3 nucleation in the upper troposphere and producing ice nucleating particles that spread across the mid-latitude Northern Hemisphere