Aug Sep Research Articles

Assessing the relative importance of dry-season incoming solar radiation and water storage dynamics during the 2005, 2010 and 2015 southern Amazon droughts: not all droughts are created equal

Three severe droughts impacted the Amazon in 2005, 2010, and 2015, leading to widespread above-average land surface temperature (LST) (i.e. positive thermal anomalies) over the southern Amazon in the dry season (Aug–Sep) of these years. Below-average dry-season incoming solar radiation (SW↓) and terrestrial water storage anomaly (TWSA) were simultaneously observed in 2005 and 2010, whereas the opposite was observed in 2015. We found that anomalies in precipitation (P), SW↓, and TWSA combined can well explain dry-season thermal anomalies during these droughts (average R2–0.51). We investigated the causes for opposing anomalies in dry-season SW↓ and TWSA, and found different hydro-climatological conditions preceding the drought-year dry seasons. In 2005 and 2010, P was considerably below average during the wet-to-dry transition season (May–July), causing below-average TWSA in the dry season that was favorable for fires. Increased atmospheric aerosols resulting from fires reduced solar radiation reaching the ground. In 2015, although below-average dry-season P was observed, it was above the average during the wet-to-dry transition season, leading to reduced fires and aerosols, and increased dry-season SW↓. To further examine the impact of opposite hydro-climatological processes on the drought severity, we compared dry-season LST during droughts with the maximum LST during non-drought years (i.e. LSTmax) for all grid cells, and a similar analysis was conducted for TWSA with the minimum TWSA (i.e. TWSAmin). Accordingly, the regions that suffered from concurrent thermal and water stress (i.e. LST > LSTmax and TWSA < TWSAmin) were identified. These regions are mainly observed over the southeast in 2005 and southern Amazon in 2010. In 2015, large-scale dry-season thermal stress was found over central and southeast Amazon with little water stress. This study underlines the complex interactions of different hydro-climatological components and the importance of understanding the evolution of droughts to better predict their possible impacts on the Amazon rainforest.

The use of Andrographis paniculata and its effects on liver biochemistry of patients with gastrointestinal problems in Thailand during the COVID-19 pandemic: a cross sectional study

In the COVID-19 pandemic, healthcare facility supply and access are limited. There was an announcement promoting Andrographis paniculata (ADG) use for treatment of mild COVID-19 patients in Thailand, but misconception of taking for prevention might occur. Moreover, the effect of ADG on liver function test (LFT) has not been established. To study the ADG use and effect on LFT in patients with gastrointestinal (GI) problems, conducted a cross-sectional study including GI patients who voluntarily filled the ADG questionnaire in Aug–Sep 2021. LFT data at that visit and at the prior visit (if available) were obtained. The changes in LFT within the same person were analyzed and compared between patients with and without ADG consumption. During the study period, a total of 810 patients completed the survey, 168 patients (20.7%) took ADG within the past month. LFT data were available in 485 (59.9%) patients, the median alanine aminotransferase (ALT) change compared with the prior visit was higher in the ADG vs control group (+ 2 vs 0, p = 0.029), and 44.5% had increased ALT (> 3 U/L) vs 32.2% in the ADG and control group, respectively (p = 0.018). Factors independently associated with an increased ALT, from a multivariable logistic regression, were ADG exposure (adjusted OR 1.62, p = 0.042), and patients with NAFLD who gained weight (adjusted OR 2.37, p = 0.046). In conclusion, one-fifth of GI patients recently took ADG, even it is not recommended for COVID-19 prevention. Those who took ADG are more likely to experience an increased ALT than who did not. The potential risk of ADG consumption on liver function should be further assessed.

Corrigendum to: (2855) Proposal to conserve the name Lilium humboldtii against L. puberulum (Liliaceae) [in Taxon 71: 231–232. 2022

In the publication, “(2855) Proposal to conserve the name Lilium humboldtii against L. puberulum (Liliaceae)” (Compton in Taxon 71: 231–232. 2022), the places of publication of these two names were given as: Lilium humboldtii J.H. Krelage (in Gard. Chron. 1870: 1402. 22 Oct 1870) and Lilium puberulum (Torr.) Leichtlin (in J. Soc. Imp. Centr. Hort., ser. 2, 4: 217. Mai 1870), based on L. canadense var. puberulum Torr. (Pacif. Railr. Rep. 4 (5 [No. 4]): 146. Aug–Sep 1857). Since publication of the proposal, Johan van Scheepen of the Royal General Bulbgrowers’ Association (KAVB) has forwarded to me a single-sheet catalogue from Max Leichtlin's bulb nursery in Karlsruhe dated “fin Mai 1870” (Leichtlin, P. P. [Praemissis Praemittendis: Liliacées du jardin Leichtlin]. 1870). In that catalogue, apparently an addendum on new Californian lilies ready for commerce, there are the following two descriptions: “2. Lilium humboldtii voisin du précédant d'une beauté remarquable à tiges atteignant jusqu’à 5 pieds de hauteur garnies de nombreuses et larges fleurs, jaune d'or tigrées de pourpre.” “3. Lilium puberulum à grands clochettes jaunes ornées de grandes macules pourprées et noires.” The species preceding Lilium humboldtii in Leichtlin's catalogue was L. washingtonianum Kellogg (in Hesperian (San Francisco) 3: 340. 1859), a species that differs in having white or pale to dark pinkish flowers. As the descriptive material provided by Krelage (l.c.) in his publication of the name (“from California, 5 feet high, golden flowers spotted with purple”) was no more extensive than that in Leichtlin's catalogue, it is evident that the name was validly published five months earlier than stated in the conservation proposal and in the same month as the competing name, L. puberulum. There is circumstantial evidence pointing to the month of May as being that in which the name Lilium puberulum was first published. This was in Duchartre's account of Max Leichtlin's lily collection that included a list of lily species by Leichtlin (in J. Soc. Imp. Centr. Hort., ser. 2, 4: 217). The April issue in which the name occurs ran from page 193, commencing with the Séance dated 14 April 1870 and including the Séance of 28 April 1870, and ended on page 255. The following page 256 introduces the May issue with the Séance of 12 May. In the “Annuaire de la Société pour 1870” that is included ahead of the main text in at least some copies of J. Soc. Imp. Centr. Hort., ser. 2, 4, there is, on p. [xciv], the statement under the general heading “Avis”: “Le Journal de la Société impériale et centrale d'Horticulture de France paraît du 5 au 15 de chaque mois, par cahiers de 32 à 64 pages.” The implication being that the instalments were due to have appeared by the 15th day in each month. This would mean that L. puberulum was intended to have been published by the 15th of the following month, i.e., by 15 May 1870. If this assumption is correct and this intention was achieved, then L. puberulum predated L. humboldtii by some two weeks. Hence, although L. puberulum was published again at the end of the month simultaneously with the first publication of L. humboldtii (Leichtlin, l.c., Mai (sero) 1870), the proposal to conserve L. humboldtii against L. puberulum (Compton in Taxon 71: 231–232. 2022) remains necessary. The corrected proposal is, therefore: (2855) Lilium humboldtii Leichtlin, P. P. [Praemissis Praemittendis: Liliacées du jardin Leichtlin]: [1]. Mai (sero) 1870 [Angiosp.: Lil.], nom. cons. prop. Typus: [icon] “Lilium Humboldtii Roezl et Leichtlin” in Gartenflora 21: t. 724. 1872. (=) Lilium puberulum (Torr.) Leichtlin in J. Soc. Imp. Centr. Hort., ser. 2, 4: 217. Mai (med) 1870 (L. canadense var. puberulum Torr., Pacif. Railr. Rep. 4 (5 [No. 4]): 146. Aug–Sep 1857), nom. rej. prop. Lectotypus (vide Compton & Skinner in PhytoKeys 182: 49. 2021): U.S.A., California, Hartweg 2004 (GH barcode 00106407).

Modeling seasonal sediment yields for a medium-scale temperate forest/agricultural watershed

ABSTRACT As vegetation cover senesces across temperate watersheds, the potential for soil erosion and subsequent sediment yields increases. Despite the importance of vegetation dynamics and evapotranspiration towards influencing watershed-scale hydrological processes, limited research has fully included these variables in modeling sediment yields, relying on surface runoff records alone. Focusing on the Upper Floyds Fork watershed, Kentucky, we applied a multi-objective approach utilizing MODIS-derived estimations of vegetation and evapotranspiration (ET) to calibrate the Soil and Water Assessment Tool (SWAT) towards modeling seasonal sediment yields May 2019-April 2020. Results generated satisfactory error measures across all four variables (vegetation cover, ET, runoff, sediment). Above average precipitation and elevated erosive storm activity generated significant sediment yields even during months of greater vegetation coverage. Conversely, below average precipitation during Aug–Sep resulted in minimal sediment yields despite diminishing vegetation coverage. While precipitation acted as the dominant process controlling sediment yields, higher yields were also predicted in sub-watersheds as a function of steeper slopes, higher soil erodibilities and increased agricultural land cover during the dormant winter period. These findings may help identify when to expect increased sediment loads towards targeting specific sub-watersheds in managing future soil erosion, and defining and establishing best management practices in the future.

Quantifying the contribution of tropical cyclones to lightning activity over the Northwest Pacific

Abstract This study quantifies the impacts of tropical cyclones (TCs) to the geographical and seasonal lightning activity over the northwest Pacific (5°–35°N, 100°–160°E), and examines the connection between the occurrence of TC lightning and El Nino–Southern Oscillation (ENSO). Lightning data from the World Wide Lightning Location Network (WWLLN) and best-track data from the China Meteorological Administration are used to investigate 263 TCs for TC seasons (Jun–Nov) in the years 2005–2017. Results show that, on average, TCs account for about 4.9% of all lightning in the domain. The highest contributions occur in the northern South China Sea and the ocean northeast of the Philippines. The monthly TC contribution varies from 2.6% to 6.1% with the greatest in July and the lowest in June. The peak location of lightning center contributed by TCs are observed a poleward shift from early summer (Jun–Jul) to late summer (Aug–Sep), and an equatorial shift from late summer to autumn (Oct–Nov). In terms of TC intensity, tropical storm strength TCs are the dominant lightning contributor (2.0%) over the northwest Pacific. A greater likelihood of lightning activity in tropical storms than in typhoons is observed during the landfall, especially within the inner core region. Super typhoons produce lightning in more eastward longitude and more equatorward latitude than weaker strength TCs. The relationship between TC lightning and ENSO reveals that TCs contribute greater lightning during La Nina periods (5.0%) than El Nino periods (3.2%) over the northwest Pacific. In El Nino years, super typhoons contribute the greatest lightning amounts (1.8%), while in La Nina years tropical storms contribute the greatest (2.2%). Infrared satellite observations indicate that the high contribution of lightning in tropical storms is due to the large occurrence of very deep convection in these storms during their landfall.

Condensed tannins as a deterrent to crop depredation by white‐tailed deer: Effects of concentration and learning

ABSTRACTAgricultural producers lose millions of dollars annually to depredation caused by ungulates. Although multiple repellents exist, most are ineffective. Tannins are a plant‐defensive compound that have an astringent taste, reduce digestibility, reduce protein availability, and toxic to rumen microbes, resulting in the reduction of feeding by large herbivores. We hypothesized that chemical application of tannins to forages would provide a nonlethal method to reduce crop depredation in areas susceptible to ungulate damage. We designed an experiment to test the effectiveness of tannins at deterring feeding by captive white‐tailed deer (Odocoileus virginianus) on soybeans and other forages in 2010–2011 at the Wildlife Research Facility at South Dakota State University in Brookings, South Dakota, USA. First, using a cafeteria trial, we monitored weekly intake rates of captive deer (n = 10) offered a selected feed treated with varying concentrations of quebracho tannins (control, 3%, 5%, 10%, and 20%). Second, we manipulated food plots (n = 3) by treating 3 separate blocks with different concentrations (0% [control], 10%, and 20%) of tannins. We monitored feeding selection relative to tannin treatments within food plots 3 times/week, during summer (May–Jul) and autumn (Aug–Sep) using scan‐sampling. During cafeteria trials, intake rate of control feed was ≥3 times greater than all other feed treated with tannins. Similarly, in manipulated food plots, application of 10% and 20% tannins resulted in a 72% and 89% reduction in probability of feeding during the summer; this pattern of selection was intensified when trials occurred in consecutive days with the same deer. Strategic application of tannins to agricultural crops in areas prone to damage may provide a natural deterrent to crop depredation by ungulates. © 2019 The Wildlife Society.

Long-term impact of Central Basin hypoxia and internal phosphorus loading on north shore water quality in Lake Erie

ABSTRACTWe hypothesized that north shore water quality of Lake Erie’s Central Basin is impacted by Central Basin hypoxia and, by extension, related to redox-dependant internal phosphorus (P) loading from the profundal sediments. To evaluate this hypothesis, we first quantified Central Basin hypoxia as hypoxic factor (HF, days in Aug–Sep that a sediment area equal to the Central Basin surface area was hypoxic) from published annual hypoxic (<2.0 mg/L dissolved oxygen) areal extent and duration. From 1985 to 2012, mean HF values were 15.2 (SE 1.45) d/Aug–Sep and ranged between 0 (1996) and 34.3 (2012) d/Aug–Sep. Second, we estimated internal load from an areal P release rate of 8 mg/m2/d, multiplied by HF. The estimate of 122 (SE 11.6) mg/m2/Aug–Sep (1985–2012, n = 28) is supported by an independent estimate of 136 (SE 20.3) mg/m2/summer (1970–1986, n = 15) computed from total P concentration increases at fall turnover and by an estimate for 1970. Third, 2013 temperature and oxygen profiles demonstrated periodic upwelling on the north shore of the Central Basin, in agreement with other studies. Fourth, we analysed P, chlorophyll a (Chl-a) and phytoplankton species data at 2 north shore drinking water intake stations. HF and internal loading were significantly correlated with summer soluble reactive P, August–October Chl-a concentrations, and cyanobacteria abundance at the Central Basin site but not at the control site in the Western Basin. While these correlations are weak, suggesting other effects including benthic productivity, they may be partially caused by hypolimnetic water circulated toward the shoreline.

Annual Gametogenesis Patterns in Two High-Latitude Corals, Alveopora japonica and Oulastrea crispata, from Jeju Island, South Korea

Sexual reproduction in corals is pivotal for the survival of populations in the face of climate change. Off Jeju Island, which lies off the south coast of Korea, a high-latitude scleractinian coral, Alveopora japonica, has experienced a population explosion over the past couple of decades (at 5–15 m depths). A second species, Oulastrea crispata, which is generally present at high latitudes and extreme environments, has a stable population and dominates in the shallow subtidal waters of southern Jeju. This study examined the annual gametogenesis patterns of A. japonica off the north (33°24′N, 126°13′E) and south (33°14′N, 126°36′E) coasts of Jeju Island, and of O. crispata in the south. Histological analysis revealed that the oogonia and spermatogonia in A. japonica developed in separate mesenterial filaments, while the gonads in O. crispata developed in the same filament. Alveopora japonica had the same brooding period during late summer and early fall (Aug–Sep 2015) at both sites. The spawning period of O. crispata was also during late summer and early fall. Brooding in A. japonica was concordant with previous observations of its planula during the brooding period. This study provides the first data on the timing of reproduction of these two high-latitude corals from Jeju Island, which may help our understanding of the population dynamics of corals in other high-latitude environments.

PL.49 Reducing the Caesarean Section (CS) Rate in a Rural Hospital in South-West Uganda

BackgroundThe fertility rate in Uganda is 6.1.1 The significance of repeated CS and the risks of labour after caesarean section are well-documented. Often CS is the most appropriate mode of...

Moving Day and Night: Highly Labile Diel Activity Patterns in a Tropical Snake

AbstractMost animals have well established diel activity patterns (e.g., diurnal, crepuscular, or nocturnal), and changes in behavior from diurnal to nocturnal are rare in single species. We radio tracked 50 keelback snakes in a single population, locating them up to four times a day, over five periods of the year in the Australian dry tropics to describe temporal variation in diel movement patterns. Snake body temperatures were also recorded to determine the relationship between activity patterns and body temperatures. Season influenced diel activity patterns significantly. Keelbacks were more likely to move, and moved further in the daytime in the mid‐dry (June–July), and late dry (Aug–Sep) seasons. In the mid‐dry season, 87 percent of movements were diurnal, whereas in the mid‐wet (Feb–March) season, although snakes were much more likely to move, only 43 percent of movements were diurnal. In the late dry season, snakes were slightly more likely to move at night than at any other time of day, and so at this time of the year, snakes could be classified as nocturnal. Thus, overall increased movements in the mid‐wet season (austral summer) were associated with more crepuscular and nocturnal movement. There was a significant relationship between individual snake body temperatures and movement rates in all seasons. Changes in movement patterns may be related to body temperature, and this diurnal species becomes cathemeral in the tropics in summer, when it is possible to maintain high body temperatures both day and night.

Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

Effects of Applying Nitrogen on Yield of Introduced Perennial Summer Grass Cultivars in Oklahoma

Infection Control and the Plumber: Neonatal ICU Outbreak of Pseudomonas and Stenotrophomonas Traced to Contaminated Water Tap “Aerators”

Table 1.JanFebMarAprMayJunJulAugSepOctNovDec# bb col/inf (2003)000101102001# bb col/inf (2004)002002102010# bb col/inf (2005)000014610110BACKGROUND/OBJECTIVES: The JGH has a 34-bed neonatal ICU with a history of infrequent pseudomonad infections, despite a large high-risk clientele. During the summer of 2005, we noted a sudden and pronounced increase in the number of babies colonized (col) and/or infected (inf) with Pseudomonas aeruginosa (Paer), Pseudomonas non-aeruginosa species (Pspe), and Stenotrophomonas maltophilia (Smal). METHODS: Epidemiologic investigation of the outbreak/cluster included: 1. monitoring the cultures of all babies; 2. extensive sampling of the NICU and case-room environment; 3. review of cleaning/disinfection procedures of all equipment;4. review of hand hygiene practices. RESULTS: The total number of col and/or inf NICU babies <b>per year</b> for the 2 years preceding the outbreak (i.e. 2003 and 2004) was 6 and 8, respectively. In 2005, there were 14 such infants, 10 of which were found during June and July alone. The number of new col and/or inf babies per month is seen in table 1. Extensive cultures revealed the absence of pseudomonads in all specimens except for the water tap "aerators" in many of the sinks of both the NICU and the Birthing Center. In collaboration with Technical Services (plumbers), a review of the installation & maintenance records of the 2 units showed that the faucets and aerators had been installed in 1992. More frequent (weekly) surface cleaning of the aerators had been instituted, with Environmental Services, in 2003. However, the aerators had never been changed. Visual inspection revealed large amounts of caked mineral deposit on the aerators. All aerators were changed between August 5-7, 2005. Only 2 babies have been found col/inf since the intervention. CONCLUSIONS: A sudden and dramatic increase in the number of neonates col and inf with pseudomonads was traced to environmental contamination of mineral-caked water faucet aerators in the NICU and the Birthing Center. Replacement of all aerators led to a rapid and sustained reduction in col and inf neonates. Contamination of water, faucets, and their accessories continue to play a role in NICU outbreaks with gram-negative organisms.

Temporal variability of stable carbon and nitrogen isotopic composition of size-fractionated particulate organic matter in the hypertrophic Sumida River Estuary of Tokyo Bay, Japan

To clarify the major factors that control stable carbon and nitrogen isotopic compositions (δ 13C and δ 15N) of suspended particulate organic matter in a hypertrophic estuary, seasonal variation in concentrations and stable isotopic compositions of particulate organic carbon and nitrogen (POC, PN), chlorophyll a content (Chl) and dry weight of suspended solid (SS) was studied in the Sumida River estuary of Tokyo Bay. Particulate material was fractioned into four size-fractions (3–20, 20–53, 53–250, 250–1000 μm). At the lower-estuarine (LE) site, the finer size fraction (<20 μm) was predominant (>80% Chl) during the autumnal bloom (Aug–Sep 2003). The middle size fractions (20–53 and 53–250 μm) however increased during the spring bloom (50–80% Chl; Feb–Apr 2004), reflecting difference in taxonomic composition of phytoplankton. At the upper-estuarine and the riverine sites, the <20 μm fraction was most abundant throughout the survey period. δ 13C POC and δ 15N PN varied between −32 and −16‰ and between −8 and +12‰, respectively. Relationships of δ 13C POC with POC/Chl and POC/PN ratios could be explained by assuming two end members: allochthonous (terrestrial) POC with a δ 13C close to −26.5‰, and autochthonous (planktonic) POC whose δ 13C was variable and apparently correlated with δ 13C of ambient DIC (−10 to 0‰) and phytoplankton abundance (Chl). δ 15N PN was apparently controlled by water temperature and NH 4 + concentration. The variability of δ 13C and δ 15N was different between size fractions: the apparent dependence of δ 13C on Chl as well as that of δ 15N on water temperature was significantly stronger for the middle size fractions (mainly diatoms) than the finer fraction (mainly microflagellates), suggesting different physiological response between taxa. The second objective of this study was to evaluate contribution of terrestrial organic carbon (TPOC) to the POC size fractions by using δ 13C of isolated chlorophyll a at LE site as surrogate for the autochthonous δ 13C end member. During the autumnal bloom, TPOC was 23–36% on average for the middle size fractions (20–53 and 53–250 μm), and ≥59% for the finest (3–20 μm) and coarsest (250–1000 μm) fractions. During the spring bloom, the average contribution of TPOC was generally low (≤21%) except for the finest fraction (36%). Negative correlation between salinity and calculated TPOC suggested that transport of terrestrial organic carbon to this estuary was controlled principally by the river discharge.

Status of LIGO data analysis

The LIGO Scientific Collaboration has completed the analysis of the data from its first science run (Aug–Sep 2002), is far along in the analysis of the second science run (Feb–April 2003), and is beginning the analysis of data taken during its third science run (Nov 2003–Jan 2004). We present in this paper an overview of the performance of the instruments during the science runs, of the data analysis efforts completed so far and of the plans for the future.

Observations on the life cycle of Procambarus acutus acutus in South Carolina culture ponds

Procambarus acutus acutus population structure and reproductive development was evaluated during the dry-culture (Aug–Sep) and the wet-culture phases (Nov–Jun) in 0.1-ha culture ponds. Two cohorts of crayfish, carryover (CO) crayfish and young-of-the-year (YOY) crayfish were present in the ponds. Young-of-the year crayfish grew throughout the 233-day wet-culture phase, averaging 0.19-mm total length (TL)/day, while CO crayfish growth occurred only during 3 of the 8-monthly sampling periods. The fastest growth occurred in fall (Nov–Dec) and spring (Apr–May) for YOY, and in March for CO crayfish. Form-I males were present in each of the wet- and dry-culture samples. Females excavated from burrows during the dry-culture phase possessed significantly greater gonadosomatic indices (GSIs) and less hepatopancreas moisture (HM) than females sampled during the wet-culture phase. Larger females, designated as CO individuals, burrowed earlier and exhibited more advanced gonad development than the smaller YOY females. Individuals of both designated cohorts oviposited eggs; however, attached young were observed only on the excavated CO crayfish. Pleopod eggs per female increased linearly with crayfish TL; however, those crayfish held in cups in the laboratory oviposited significantly more eggs than the females excavated from burrows. Crayfish held in cups oviposited 96% of the eggs in their ovaries. The life cycle traits of P. a. acutus limit the harvest to one recruitment wave in South Carolina culture ponds.

Soybean Response to Foliar Applied Methanol in Humid and Semiarid Environments

Recent research from a desert environment in Arizona suggested that foliar application of dilute solutions of methanol substantially increased yield, quality, and water-use efficiency of several C 3 plant species. However, soybean [Glycine max (L.) Merr.], which is one of the major agronomic C 3 crops of the USA, was not included. Therefore, this research was initiated to compare effects of methanol solution concentrations applied to soybean at different reproductive growth stages under field conditions in humid and semiarid environments. The experiment was conducted in 1994 and 1995 at two irrigated (limited and full) locations in semiarid, northwestern Kansas and at one dryland location in humid, southeastern Kansas. Soil moisture was determined for these growing seasons. Each of two methanol concentrations (20 and 40%, v/v) was applied either in a single application at growth stages R1, R3, and R5 or in multiple applications involving all combinations of these three for a total of seven treatments involving stage of growth. One untreated control plot was maintained in each replication. Neither methanol concentration nor time of application affected grain yield, yield components, or seed quality or soil-plant water relations. In addition, no difference was detected between the average responses to methanol application and the untreated control. Thus, we conclude that soybean responses to foliar applications of methanol are not effective under either humid or semiarid conditions typical of those found in Kansas and much of the Great Plains.

Seasonal variations of the thermal structure of the mesopause region at Urbana, IL (40° N, 88° W) and Ft. Collins, CO (41° N, 105° W)

Beginning in 1991, Na lidars were used to make routine measurements of the temperature structure between 80 and 105 km altitude during 65 nights at Urbana, IL and 116 nights at Ft. Collins, CO. More than 13,000 temperature profiles representing more than 1100 h of observations were used to characterize the seasonal temperature variations in the upper mesosphere and lower thermosphere. The seasonal behavior is quite similar at the two sites. The mesopause altitude is near 100 km in winter during Nov–Feb and near 86 km in summer during May–Jul. The mesopause temperature varies from 190 K in mid‐winter to 175 K in mid‐summer. The transitions between winter and summer mesopause structures occur rapidly in Mar–Apr and Aug–Sep. The temperature differences between the two sites are less than ±15 K and appear to be the result of atmospheric planetary, tidal, and gravity wave perturbations.

The combined effects of chlorine and ammonia on litter breakdown in outdoor experimental streams

The response of Potamogeton crispus L. breakdown to controlled doses of different levels of chlorine and chlorine + ammonia was investigated over two years in outdoor experimental streams. In 1985, downstream riffles of 2 streams were dosed (observed in-stream concentrations) at ca. 10 µg/L Total Residual Chlorine (TRC), one stream at 64 µg/L TRC and one stream at 230 µg/L TRC. Two control streams were not dosed and the upstream riffles of each stream served as within stream controls. In 1986, the downstream riffle of one stream was dosed at 70 µg/L TRC and a second stream was dosed at 200 µg/L TRC. Four streams were also dosed with 2.5 mg/L NH3-N: one stream with no chlorine, one stream with ca. 10 µg/L TRC, one with 56 µg/L TRC, and one with 150 µg/L TRC. A seventh stream was dosed for 2 h at 2000 µg/L TRC and 2.5 mg/L ammonia and then allowed to recover (recovery stream). Each year, litter decomposition (degree day k values) was measured during two 35 day trials (Jun–Jul and Aug–Sep). In 1985, when streams were dosed with chlorine alone, decomposition was significantly reduced with the high (230 µg/L TRC) chlorine dose. Downstream decomposition was 27% (Jun–Jul) and 59% (Aug–Sep) of the upstream (control) rate. No other chlorine effects were found during this period. In Jun–Jul 1986, there was significantly lower decomposition in the downstream dosed sites of the 200 µg/L TRC alone stream, the 146 µg/L TRC + ammonia stream and the recovery stream; downstream decay rates were (respectively) 56%, 42% and 64% of the upstream control sites. No other up-down pairs were different in July 1986. In Aug–Sep, all three streams with chlorine + ammonia (6, 56 and 146 µg/L TRC + 2,5 mg/L ammonia) and the 70 µg/L TRC alone stream had significantly lower decomposition rates in the downstream dosed sites. For these streams, downstream decay rates ranged from 46% (high chlorine + ammonia) to 73% (low chlorine + ammonia) of the upstream control rates. No other up-down pairs were different during this trial. Up and downstream sites of the stream dosed with 2.5 mg/L ammonia alone were nearly identical for both trials (< 3% difference). These results indicate that TRC at less than 250 µg/L can significantly reduce litter decomposition and strongly suggest that addition of ammonia to chlorinated water can increase the toxic effect of chlorine.

Performance and Phosphorus Status of Range Cows with and without Phosphorus Supplementation

Performance and Phosphorus Status of Range Cows with and without Phosphorus Supplementation

Temperature and larval development of Carcinus maenas (Decapoda) in the laboratory; predictions of larval dynamics in the sea

Temperature and larval development of Carcinus maenas (Decapoda) in the laboratory; predictions of larval dynamics in the sea