Showing papers by "University of New Hampshire published in 2022"

Urbanization Contributes Little to Global Warming but Substantially Intensifies Local and Regional Land Surface Warming

Abstract: Increasing urbanization causes an urban heat island (UHI) effect and exacerbates health risks of heat waves due to global warming. The surface UHI (SUHI) in large cities has been extensively studied, yet a systematic evaluation on the impacts of urbanization on local-to global-scale land surface warming is lacking. We propose a new procedure to quantify the warming effects of urbanization at local, regional, and global scales using high-resolution satellite observations. We find strong local warming effects for 88% of the urban-dominated pixels across the globe and cooling effects for the rest of the urban lands on a diurnal mean timescale, with a global urban mean intensity of 1.1°C in 2015. The SUHI effects differ substantially by time of day, season, and climate zone, and are closely related to surface evapotranspiration. By extending local effects to the entire land surface, we estimate a diurnal mean warming of only 0.008°C globally. However, urbanization can have large warming effects regionally, especially in eastern China, the eastern United States, and Europe. In addition, we show that global urban expansion results in over three-quarters of SUHI effects in 1985–2015, and its effect will likely increase by 50%–200% by the end of this century. The SUHI-added warming could be up to 0.12°C in summer in Europe by 2100 under a fossil-fueled development pathway. Our results reveal that urbanization substantially intensifies local and regional land surface warming and that prioritized attention should be given to the SUHI-added warming in highly or rapidly urbanized regions.

Impact of the COVID-19 Pandemic on Perceptions of Health and Well-Being Among Sexual and Gender Minority Adolescents and Emerging Adults

Abstract: Purpose: The study purpose was to examine how the COVID-19 pandemic may be differentially impacting the well-being of sexual and gender minority (SGM) youth compared with their non-SGM counterparts. Specifically, we looked at perceptions of mental and physical health impact and relevant aspects of coping with the pandemic such as engagement in prosocial activities that might ultimately promote resilience. Methods: Survey data were collected between November 27, 2020, and December 11, 2020, from 990 adolescents and emerging adults aged 13-23 years. Participants were recruited through advertisements on Facebook and Instagram with an effort to overrecruit SGM youth. Questions asked youth about their perception of the impact of the COVID-19 pandemic on their physical and mental health, the types of prosocial activities engaged in during the pandemic, and how they felt they were doing now versus before the pandemic. Results: SGM youth reported a significantly greater impact from the pandemic than non-SGM youth. Both SGM youth and cisgender heterosexual females reported greater impact on their mental health compared with cisgender heterosexual males, with cisgender sexual minority females and gender minority youth reporting the highest mental health impact. Gender minority youth also reported feeling less connected to their families and less safe at home as a result of the pandemic. Conclusion: Health professionals, educators, and advocates need to help assess SGM youth for negative impact from the pandemic and help them connect with other youth and support resources online as they move forward. Youth may also benefit from programs connecting them to volunteer work and neighbors.

Causes and Consequences of Magnetic Complexity Changes within Interplanetary Coronal Mass Ejections: A Statistical Study

Abstract: We present the first statistical analysis of complexity changes affecting the magnetic structure of interplanetary coronal mass ejections (ICMEs), with the aim of answering the questions: How frequently do ICMEs undergo magnetic complexity changes during propagation? What are the causes of such changes? Do the in situ properties of ICMEs differ depending on whether they exhibit complexity changes? We consider multi-spacecraft observations of 31 ICMEs by MESSENGER, Venus Express, ACE, and STEREO between 2008 and 2014 while radially aligned. By analyzing their magnetic properties at the inner and outer spacecraft, we identify complexity changes which manifest as fundamental alterations or significant re-orientations of the ICME. Plasma and suprathermal electron data at 1 au, and simulations of the solar wind enable us to reconstruct the propagation scenario for each event, and to identify critical factors controlling their evolution. Results show that ~65% of ICMEs change their complexity between Mercury and 1 au and that interaction with multiple large-scale solar wind structures is the driver of these changes. Furthermore, 71% of ICMEs observed at large radial (>0.4 au) but small longitudinal (<15 degrees) separations exhibit complexity changes, indicating that propagation over large distances strongly affects ICMEs. Results also suggest ICMEs may be magnetically coherent over angular scales of at least 15 degrees, supporting earlier theoretical and observational estimates. This work presents statistical evidence that magnetic complexity changes are consequences of ICME interactions with large-scale solar wind structures, rather than intrinsic to ICME evolution, and that such changes are only partly identifiable from in situ measurements at 1 au.

Conducting and characterizing femto flow electrospray ionization

Abstract: Femto flow electrospray ionization (ESI) with flow rates ranging from 240 fL min-1 to the low pico level (<10 pL min-1) was conducted and measured using a submicron emitter tip and relay ESI configuration. Signature analyte ion current intensities and profiles were observed. The obtained flow rate and ionization current enabled size calculation for initial charged nanodroplets.

Follow-up Observations of the Prolonged, Super-Eddington, Tidal Disruption Event Candidate 3XMM J150052.0+015452: the Slow Decline Continues

Abstract: The X-ray source 3XMM~J150052.0+015452 was discovered as a spectacular tidal disruption event candidate during a prolonged ($>11$ yrs) outburst (Lin et al. 2017). It exhibited unique quasi-soft X-ray spectra of characteristic temperature $kT\sim0.3$ keV for several years at the peak, but in a recent Chandra observation (10 yrs into the outburst) a super-soft X-ray spectrum of $kT\sim0.15$ keV was detected. Such dramatic spectral softening could signal the transition from the super-Eddington to thermal state or the temporary presence of a warm absorber. Here we report on our study of four new XMM-Newton follow-up observations of the source. We found that they all showed super-soft spectra, suggesting that the source had remained super-soft for $>5$ yrs. Then its spectral change is best explained as due to the super-Eddington to thermal spectral state transition. The fits to the thermal state spectra suggested a smaller absorption toward the source than that obtained in Lin et al. (2017). This led us to update the modeling of the event as due to the disruption of a 0.75 msun star by a massive black hole of a few$\times10^5$ msun. We also obtained two HST images in the F606W and F814W filters and found that the dwarf star-forming host galaxy can be resolved into a dominant disk and a smaller bulge. No central point source was clearly seen in either filter, ruling out strong optical emission associated with the X-ray activity.

LOFAR Observations of Lightning Initial Breakdown Pulses

Abstract: This paper reports an observational study of lightning initial breakdown pulses (IBPs) using the low-frequency array radio telescope and a broadband magnetic field sensor. The data show that the overall spatiotemporal evolution of the electrical breakdown causing an IBP is rather complex. During an IBP, spatially and temporally separated bursts of very high frequency (VHF) electromagnetic radiation occur in a volume on the order of 1003 m3, and they are coincident with brief magnetic field pulses, indicating that the location of the active breakdown region can change suddenly. Furthermore, recurrent breakdown activity is observed, especially at the location of the VHF burst. Interpreting each VHF burst as being generated by a corona burst, an IBP pulse appears to start off from an initial corona burst and subsequent corona bursts enhance it. We further suggest that the generation of IBPs likely involves multiple space stems/leaders and connections between them.

Divergent Hydrological Responses to Forest Expansion in Dry and Wet Basins of China: Implications for Future Afforestation Planning

Abstract: Afforestation to control soil erosion has been implemented throughout China over the past few decades. The long-term hydrological effects, such as total water yield and baseflow, of this large-scale anthropogenic activity remain unclear. Using six decades of hydrologic observations and remote sensing data, we explore the hydrological responses to forest expansion in four basins with contrasting climates across China. No significant change in runoff was found for the period 1970–2012 for the cold and dry Hailar River Basin in northeastern China. However, both forest expansion and reduced precipitation contributed to the runoff reduction after afforestation since the late 1990s. Similarly, afforestation and drying climate since the mid-1990s induced a significant decrease in runoff for the Weihe River Basin in semi-arid northwestern China. In contrast, the two wet basins in the humid southern China, Ganjiang River Basin and Dongjiang River Basin, showed insignificant changes in total runoff during their study periods. However, the baseflow in the winter dry seasons in these two watersheds significantly increased since the 1950s. Our results highlight the long-term variable effects of forest expansion and local climatic variability on basin hydrology in different climatic regions. This study suggests that landuse change in the humid study watersheds did not cause dramatic change in river flow and that region-specific afforestation policy should be considered to deal with forestation-water quantity trade-off. Conclusions from this study can help improve decision-making for ecological restoration policies and water resource management in China and other countries where intensive afforestation efforts are taking place.

Geometrically stabilized skyrmionic vortex in FeGe tetrahedral nanoparticles

Abstract: The concept of topology has dramatically expanded the research landscape of magnetism, leading to the discovery of numerous magnetic textures with intriguing topological properties. A magnetic skyrmion is an emergent topological magnetic texture with a string-like structure in three dimensions and a disk-like structure in one and two dimensions. Skyrmions in zero dimensions have remained elusive due to challenges from many competing orders. Here, by combining electron holography and micromagnetic simulations, we uncover the real-space magnetic configurations of a skyrmionic vortex structure confined in a B20-type FeGe tetrahedral nanoparticle. An isolated skyrmionic vortex forms at the ground state and this texture shows excellent robustness against temperature without applying a magnetic field. Our findings shed light on zero-dimensional geometrical confinement as a route to engineer and manipulate individual skyrmionic metastructures.

A multi-instrumental and modeling analysis of the ionospheric responses to the solar eclipse on 14 December 2020 over the Brazilian region

Abstract: Abstract. This work presents an analysis of the ionospheric responses to the solar eclipse that occurred on 14 December 2020 over the Brazilian sector. This event partially covers the south of Brazil, providing an excellent opportunity to study the modifications in the peculiarities that occur in this sector, as the equatorial ionization anomaly (EIA). Therefore, we used the Digisonde data available in this period for two sites: Campo Grande (CG; 20.47∘ S, 54.60∘ W; dip ∼23∘ S) and Cachoeira Paulista (CXP; 22.70∘ S, 45.01∘ W; dip ∼35∘ S), assessing the E and F regions and Es layer behaviors. Additionally, a numerical model (MIRE, Portuguese acronym for E Region Ionospheric Model) is used to analyze the E layer dynamics modification around these times. The results show the F1 region disappearance and an apparent electronic density reduction in the E region during the solar eclipse. We also analyzed the total electron content (TEC) maps from the Global Navigation Satellite System (GNSS) that indicate a weakness in the EIA. On the other hand, we observe the rise of the Es layer electron density, which is related to the gravity waves strengthened during solar eclipse events. Finally, our results lead to a better understanding of the restructuring mechanisms in the ionosphere at low latitudes during the solar eclipse events, even though they only partially reached the studied regions.

The dual pandemic: COVID-19, systemic racism, and college student-athletic mental health

Abstract: The dual pandemic of 2020 – COVID-19 and systemic racism – continues to reshape society. The current study examines how this dual pandemic contributes to the psychological distress of college student-athletes, with attention to college student-athletes who identify as Black, Indigenous, or people of colour (BIPOC). A total of 222 student-athletes from nine universities completed the online survey. Student-athletes reported COVID-19 had a moderate impact on daily life. The direct effect of COVID-19 on psychological distress was found to be positive and significant but did not differ for BIPOC and White participants. Additionally, nearly all BIPOC student-athletes reported experiencing systemic racism; yet the level of systemic racism did not predict psychological distress. Findings provide insight related to the importance of mental health among college student-athletes.

Discharge Determines Avulsion Regime in Model Experiments With Vegetated and Unvegetated Deltas

Abstract: The dynamics and morphological evolution of deltas and their channel networks involve interactions between many factors, including water and sediment discharge and cohesion from fine sediment and vegetation. These interactions are likely to affect how strongly vegetation influences deltas. Altering water or sediment discharge may affect channel mobility, magnitude of deposition and erosion events, and may result in the delta being less suitable for vegetation colonization. Using the numerical model DeltaRCM Vegetation, we explore how water and sediment discharge affects delta evolution and under which conditions vegetation exerts a stabilizing effect on the channel network. We propose new insights into delta evolution under different discharge conditions. First, we observe a regime shift in avulsion dynamics, driven by delta-scale water surface slopes, with increasing water discharge: from a few active channels undergoing occasional complete, global avulsions (with low discharge) to many active channels experiencing frequent partial, local avulsions (with high discharge). Second, with vegetation, increased sediment discharge results in more frequent switching of the dominant channels but also prevents vegetation from establishing in non-dominant channels, resulting in more frequent channel reoccupation and therefore greater stability in channel network planform. These insights have important implications for understanding the distribution of water, sediment, and nutrients on deltas in the face of future changes in climate and human modifications of fluxes of sediment and water to the coast, especially for restored or engineered deltas with controlled water or sediment discharges.

Design of a flexible robot toward transbronchial lung biopsy

Abstract: Abstract Transbronchial lung biopsy is an effective and less-invasive treatment for the early diagnosis of lung cancer. However, the limited dexterity of existing endoscopic instruments and the complexity of bronchial access prevent the application of such procedures mainly for biopsy and diagnosis. This paper proposes a flexible robot for transbronchial lung biopsy with a cable-driven mechanism-based flexible manipulator. The robotic system of transbronchial lung biopsy is presented in detail, including the snake-bone end effector, the flexible catheters and the actuation unit. The kinematic analysis of the snake-bone end effector is conducted for the master-slave control. The experimental results show that the end effector reaches the target nodule through a narrow and tortuous pathway in a bronchial model. In conclusion, the proposed robotic system contributes to the field of advanced endoscopic surgery with high flexibility and controllability.

Microtopography Matters: Belowground CH ₄ Cycling Regulated by Differing Microbial Processes in Peatland Hummocks and Lawns

Abstract: Water table depth and vegetation are key controls of methane (CH4) emissions from peatlands. Microtopography integrates these factors into features called microforms. Microforms often differ in CH4 emissions, but microform-dependent patterns of belowground CH4 cycling remain less clearly resolved. To investigate the impact of microtopography on belowground CH4 cycling, we characterized depth profiles of the community composition and activity of CH4-cycling microbes using 16S rRNA amplicon sequencing, incubations, and measurements of porewater CH4 concentration and isotopic composition from hummocks and lawns at Sallie's Fen in NH, USA. Geochemical proxies of methanogenesis and methanotrophy indicated that microforms differ in dominant microbial CH4 cycling processes. Hummocks, where water table depth is lower, had higher porewater redox potential (Eh) and higher porewater δ13C-CH4 values in the upper 30 cm than lawns, where water table depth is closer to the peat surface. Porewater δ13C-CH4 and δD-CH3D values were highest at the surface of hummocks where the ratio of methanotrophs to methanogens was also greatest. These results suggest that belowground CH4 cycling in hummocks is more strongly regulated by methanotrophy, while in lawns methanogenesis is more dominant. We also investigated controls of porewater CH4 chemistry. The ratio of the relative abundance of methanotrophs to methanogens was the strongest predictor of porewater CH4 concentration and δ13C-CH4, while vegetation composition had minimal influence. As microbial community composition was strongly influenced by redox conditions but not vegetation, we conclude that water table depth is a stronger control of belowground CH4 cycling across microforms than vegetation.

Morphological, Physiological, and Biochemical Modulations in Crops under Salt Stress

Abstract: Crop plants are affected by biotic and abiotic stresses (including salinity) and such stresses may affect the growth and yield of these crop plants seriously. High temperature (due to climate change) has also changed the pattern of precipitation and caused rise in sea level. These two factors have impacted soil salinization. To address such problems naturally, the crop plants adapt themselves by different mechanisms including changes in morphological, physiological, and biochemical processes. Both ions including sodium and chloride are the main ions, that become the reason for many physio-biochemical modulations inside plant tissues, in a similar way, chloride ion is the most dangerous because NaCl releases around 60% more ions in soil comparatively with Na2SO4. An extra amount of such types of salts increases the osmotic potential in soil matrix consequently the water absorbance by plants is reduced that leads towards physiological stresses or drought. This increase of Cl− relates to salt tolerance that is linked to plant growth, water use efficiency, and transpiration. Increasing salinity in the nutrient solution reduces growth directly and restricts leaf and root mineral fixing. In this chapter, we have discussed insights into various kinds of morphological, physiological, anatomical, and biochemical modulations in plants caused by abiotic stresses especially salinity. In the era of climate change, plant scientists should focus on each shotgun approaches as well as long-term genomic techniques to enhance salt tolerance in commercially important crops to ensure food security and sustainable productivity.