Short-term Drop Research Articles

Water Use Efficiency in Cucumis sativus L. in Response to Daily Short-Term Temperature Drop

This study investigates the effect of daily short-term (2 h) low temperature treatment (12 °C) (DROP) on photosynthetic water use efficiency (WUE) at leaf level of cucumber plants. The DROP treatment caused an increase of WUE in the leaves treated by DROP during their early growth (D1), but not in leaves which were already mature during the treatment (D2). The WUE increase in D1 compared to D2 leaves was due to higher net photosynthetic rate at low temperature or lower transpiration rate at common temperature. The elongation of the DROP treatment from early growth stage until full maturation of leaves did not lead to an additional increase in WUE compared to the leaves treated by DROP only during their early growth.

Skin temperature reveals the intensity of acute stress

Acute stress triggers peripheral vasoconstriction, causing a rapid, short-term drop in skin temperature in homeotherms. We tested, for the first time, whether this response has the potential to quantify stress, by exhibiting proportionality with stressor intensity. We used established behavioural and hormonal markers: activity level and corticosterone level, to validate a mild and more severe form of an acute restraint stressor in hens (Gallus gallus domesticus). We then used infrared thermography (IRT) to non-invasively collect continuous temperature measurements following exposure to these two intensities of acute handling stress. In the comb and wattle, two skin regions with a known thermoregulatory role, stressor intensity predicted the extent of initial skin cooling, and also the occurrence of a more delayed skin warming, providing two opportunities to quantify stress. With the present, cost-effective availability of IRT technology, this non-invasive and continuous method of stress assessment in unrestrained animals has the potential to become common practice in pure and applied research.

Effect of titanium and molybdenum on the structure and mechanical properties of an in situ composite based on the niobium-silicon system

Composites of the Nb-Si-T-Zr-Hf-Cr-Al-Mo-Y system of three compositions differing only by their ratios of molybdenum and titanium content (13 at % Ti + 8.5 at % Mo; 15 at % Ti + 6.5 at % Mo; and 17 at % Ti + 4.5 at % Mo) are investigated. Composite samples are prepared via directional solidification at a pulling rate of 5 mm min–1. The main structural components of the composite are Nbss-based solid solution and solid solution based on intermetallic compounds Nb3Si, β-Nb5Si3, and α-Nb5Si3. According to data from short-term strength tests at 1300 and 1350°C, the average values of the short-term flexural strength drop as the molybdenum content falls and the titanium content rises from 950 to 707 MPa and from 562 to 433MPa. The rate of creep deformation at 1300°C and a stress of 200 MPa rises from 9.8 × 10–5 to 10.6 × 10–3 h–1.

Response of the photosynthetic apparatus in cucumber leaves to daily short-term temperature drops

Responses of the photosynthetic apparatus in cucumber (Cucumis sativus L.) leaves were examined after exposing the plants to daily short-term temperature drops to 12°C (for 2 h at the end of night periods, DROP treatment) during active leaf growth (DROPI) and at the mature leaf stage (DROPII). The DROP treatment induced adaptive changes in the photosynthetic apparatus that were evident in elevated photosynthetic activity at low temperature, modified composition of pigments, altered water content in leaves, and altered ratio of leaf dry matter to leaf area. The stage of leaf development had a significant influence on the responses of photosynthetic apparatus to DROP treatments. The leaves subjected to DROP during active growth were capable of large structural rearrangements, which provided a larger increase in resistance of photosynthesis to low temperature, whereas the leaves exposed to temperature drops at the mature leaf state were characterized by the reduced capacity for acclimation.

DOES ICT CAPITAL AFFECT ECONOMIC GROWTH IN THE EU-15 AND EU-12 COUNTRIES?

The paper examines economic growth in old and new member countries of the European Union (EU-15 and EU-12) during the years of 1994–2000 and 2001–2008 mainly due to changes in information and communication technology (ICT) capital development. The first group EU-15 is presented by old EU countries and the second group EU-12 is presented by new member countries that joined the EU in 2004–2007. The threefactor Cobb-Douglas production function is estimated through the panel general least squares method. The input factors that might influence the economic growth are labour, ICT capital services and non-ICT capital services. Since ICT capital growth data are not available for all selected economies, the groups of countries were reduced to EU-14 and EU-7. The estimated panel production functions confirmed that the average growth of GDP in the EU-7 countries was supported by the stable growth of labour quantity and ICT-capital and increasing total factor productivity. A short-term drop in non-ICT capital growth with follow-up stagnation was caused rather by lower labour productivity. The research discovered that the drop in GDP growth in the EU-14 countries was a result of the slower growth of non-ICT capital and total factor productivity and the stagnated growth of ICT capital with low elasticity, and showed that even the compensation of growth in labour quality did not prevent a decrease in total factor productivity and economic growth.

도시지역의 지하수수지

The study analyzes groundwater balance with regard to the water recharge and discharge which contain urbanization components in Suyeong-gu, Busan. It also verifies the reliability and accuracy improvement on the analysis of the balance. The result of the study is viewed as preliminary data which are useful to develop, utilize and manage groundwater. The average quantity of groundwater recharge is 6,014.1 ㎥/day in the research area during the last ten year period(from 1998 to 2007). The outflow from drainage areas to rivers and coasts is 149.3 ㎥/day, the inflow from rivers and coasts to drainage area is 439.9 ㎥/day. The use of the water is 4,243.0 ㎥/day. The outflow caused by subway in line No.2 and No.3 through Suyeong-gu and the one by building an underground electric complex is 1,500.0 ㎥/day. The leakage of water works is 6514.9 ㎥/day. The inflow and outflow of sewerage is 5082.2 ㎥/day from groundwater to sewer. The amount of groundwater recharge, the inflow from rivers and coasts to drainage area, and the leakage of water works belong to the amount of groundwater inflow and the total amount is 12,968.9 ㎥/day. The amount of outflow from drainage area to rivers and coasts, the use of groundwater, outflow by subway and underground electric complex tunnel and the amount of inflow of the water to sewerage belong to the amount of outflow of groundwater and the sum amount is 13,031.5 ㎥/day. The gap between the amount of inflow and outflow of groundwater is 62.6 ㎥/day, which is considered to reflect the trend that the short term drop in the amount of rainfall results in the amount of groundwater recharge and that the amount of outflow from drainage area to rivers and coasts decreases.

Ecological development of Lake Donggi Cona, north-eastern Tibetan Plateau, since the late glacial on basis of organic geochemical proxies and non-pollen palynomorphs

Organic geochemical proxy data from surface sediment samples and a sediment core from Lake Donggi Cona were used to infer environmental changes on the northeastern Tibetan Plateau spanning the last 18.4 kyr. Long-chain n-alkanes dominate the aliphatic hydrocarbon fraction of the sediment extract from most surface sediment samples and the sediment core. Unsaturated mid-chain n-alkanes ( nC 23:1 and nC 25:1) have high abundances in some samples, especially in core samples from the late glacial and early Holocene. TOC contents, organic biomarker and non-pollen-palynomorph concentrations and results from organic petrologic analysis on selected samples suggest three major episodes in the history of Lake Donggi Cona. Before ca. 12.6 cal ka BP samples contain low amounts of organic matter due to cold and arid conditions during the late glacial. After 12.6 cal ka BP, relatively high contents of TOC and concentrations of Botryococcus fossils, as well as enhanced concentrations of mid-chain n-alkanes and n-alkenes suggest a higher primary and macrophyte productivity than at present. This is supported by high contents of palynomorphs derived from higher plants and algae and was possibly triggered by a decrease of salinity and amelioration of climate during the early Holocene. Since 6.8 cal ka BP Lake Donggi Cona has been an oligotrophic freshwater lake. Proxy data suggest that variations in insolation drive ecological changes in the lake, with increased aquatic productivity during the early Holocene summer insolation maximum. Short-term drops of TOC contents or biomarker concentrations (at 9.9 cal ka BP, after 8.0 and between 3.5 and 1.7 cal ka BP) can possibly be related to relatively cool and dry episodes reported from other sites on the north-eastern Tibetan Plateau, which are hypothesized to occur in phase with Northern Hemisphere cooling events.

Penile erectile activity of dinitrosyl iron complexes with thiol-containing ligands

It has been established that intracavernous injections of water-soluble dinitrosyl iron complexes (DNIC) with glutathione or cysteine (0.4–6.0μmoles/kg) to male rats induce short-term (2–3min) penile erection along with a short-term drop of arterial pressure and appearance of protein-bound DNIC in cavernous tissue and circulating blood. The duration of erection and the hypotensive activity of DNIC increase dramatically after simultaneous intracavernous injection of DNIC and the phosphodiesterase-5 inhibitor papaverine. Surgical denervation of cavernous bodies does not influence the erectile activity of DNIC. No penile erection takes place after intravenous (instead of intracavernous) injection of the same dose of DNIC; in this case, protein-bound DNIC are detected only in the blood. These findings suggest that water-soluble DNIC with thiol-containing ligands (cysteine or glutathione) can be used as a basis in the design of a novel class of drugs for treating erectile dysfunctions.

Beach Sediments from Northern South China Sea Suggest High and Oscillating Sea Levels During the Late Holocene

Understanding the history of the late Holocene sea level change is critical for predicting the potential effects of future sea level changes. The coral reef region of the Leizhou Peninsula, in the northern coast of the South China Sea, is an ideal site for studying the Holocene sea level history because of its tectonic stability and the possession of numerous prehistoric sea level indicators. The paleobeach sedimentary records from the Leizhou Peninsula indicated a higher-than-present sea level stand, from 1.7 to 1.2 Cal. ka BP (or 14C ages from 2.1 to 1.7 ka BP), which was punctuated by a short-term drop in the sea level at ∼1.5 Cal. ka BP. At 1.2 Cal. ka BP, the sea level was at least 128 cm higher than the present level. After that time, the sea level fell significantly resulting in the retreat of the coastline by ∼210 m and the formation of the modern beach-sand bank geomorphic system. Additional evidence from the coral reef records at this site suggested that similar to the climate change, the sea level also oscillated in the millennial-, centennial-, and interdecadal-scale cycles over the mid-late Holocene.

Hiring Stars and Their Colleagues: Exploration and Exploitation in Professional Service Firms

This paper examines exploration and exploitation in professional service firms by focusing on the individuals who carry out the exploration and exploitation activities. Specifically, we examine the performance of star security analysts who join new firms in exploration versus exploitation roles. We find that stars hired to explore (initiate new activities) experience a short- and long-term performance decline; by contrast, stars who join new firms to exploit (reinforce existing activities) suffer only a short-term drop in performance. Stars hired in exploration roles can preserve some of their performance by moving with a group of colleagues from the originating firm. Investors view the hiring of a star analyst as value-destroying for the hiring firm regardless of whether the firm is hiring to exploit or explore, but the negative reactions are economically more extreme for exploration hires. These findings indicate that, even at the individual level, probabilities of success in exploration activities are lower than in exploitation activities, thereby reinforcing the tendency toward exploitation.

Water quality limits for Atlantic salmon (<i>Salmo salar</i> L.) exposed to short term reductions in pH and increased aluminum simulating episodes

Abstract. Acidification has caused the loss or reduction of numerous Atlantic salmon (Salmo salar L.) populations on both sides of the North Atlantic. Acid deposition peaked in the 1980's and resulted in both chronically and episodically acidified rivers. At present, water quality is improving in all affected rivers due to reduced acid deposition. However, spring snow melt, heavy rainfall and sea salt episodes can still cause short term drops in pH and elevated concentrations of bioavailable aluminum. Technical malfunction in lime dozers will cause short termed episodic spates in the limed rivers. The current situation has prompted a need for dose-response relationships based on short term exposures of Atlantic salmon to assess the potential population effects of episodic acidification. Water quality guidelines for salmon have been lacking, despite a large number of experiments, all demonstrating dose-response relationships between water chemistry and fish health. We have summarized results from 347 short-term (<14 days) exposures of salmon parr and smolt performed between 1990 and 2003 in Norway. The experiments have been performed as bioassays, where fish have been exposed in tanks fed river water, in tanks where the river water quality has been manipulated (added H+ and Al) and as Carlin-tagged smolt releases after preexposure to moderately acidic waters. The results from the various bioassays are compared to water quality limits proposed on basis of the relationship between water quality and population status/health in Norwegian rivers. The focus of this article is placed on chemical-biological interactions that can be drawn across experiments and exposure protocols. We propose dose-response relationships for acid neutralizing capacity (ANC), pH, cationic Al and gill accumulated Al, versus mortality in freshwater, effects on hypo-osmoregulatory capacity in seawater challenge tests and on smolt to adult survival in release experiments. The "no effect" dose depends on the life history stage tested and on the sensitivity of the biomarkers. Parr are more tolerant than smolt. Concentrations of Al that have no significant impact on freshwater life history stages can still have major population effects if they occur prior to smolt migration. While smolt can survive in freshwater for a prolonged period of time (>10 days) at an Al dose resulting in a gill Al concentration of up to 300 µg Alg−1 dw, a 3 day exposure resulting in a gill Al accumulation in the range of 25 to 60 µg Alg−1 dw reduces smolt to adult survival in a dose related manner by 20 to 50%. For smolt to adult survival, the biological significant response is delayed relative to the dose and occurs first after the fish enters the marine environment. In addition to exposure intensity and timing, exposure duration is important for the setting of critical limits.

A Longitudinal Analysis of Foreign Program Imports on South Korean Television, 1978–2002: A Case of Rising Indigenous Capacity in Program Supply

A time-series analysis using the 25-year longitudinal data shows that the proportion of foreign imports aired on the Korean terrestrial broadcasters decreased between 1978 and 2002. The findings indicate that Korea's competitiveness in producing television content has risen over the period, as Korea's economy and television advertising market grew consistently and rapidly in spite of the short-term drop in the late 1990s. The rise of domestic television programming output was particularly evident in drama series. The Korean case defies the crude form of Americanization of television in developing countries. However, it also shows that it will take time and resources for a country to enter into the phase of increasing indigenous television content.

Safety and Tolerability of Long Lasting LDL‐apheresis in Familial Hyperlipoproteinemia

The aim of this work is to arbitrate the incidence of side effects and tolerability of long lasting LDL-apheresis in familial hyperlipoproteinemia. 1200 procedures were performed and the last 463 of them were evaluated. An immunoadsorption method of LDL-apheresis was used (continuous blood cell separator Cobe Spectra; secondary device: automated adsorption-desorption ADA, Medicap; absorption columns: Lipopak). As a whole, 6.26% adverse events were found and subsequently resolved by standard symptomatic therapy. Vaso-vagal reactions (symptoms of neurovegetative lability) were the most common adverse effects, presented as malaise, weakness, slight and short-term drop in blood pressure or other general signs. They were all well controlled by symptomatic therapy. We conclude that LDL-apheresis in the hands of experienced personnel is a safe procedure. An acceptable procedure duration limit, balancing the possibility to achieve a targeted cholesterol level while still maintaining an acceptable patient tolerance, was confirmed to be 4 hours.

Lower gas prices at the expense of the environment?

In April, I began to think about bicycling more. With gasoline prices on the rise and outraged consumers calling for the scalps of the oil companies, President Bush was watching his popularity spiraling downward. He asked Stephen L Johnson, the Administrator of the Environmental Protection Agency (EPA), to use all of his authority to grant waivers relieving critical fuel supply shortages. The President justified the request by stating that, “I do that for the sake of our consumers. If Johnson finds that he needs more authority to relieve the problem, we're going to work with Congress to obtain the authority he needs.” The President was asking the EPA to relax fuel blend rules and reformulated gasoline regulations that are designed to alleviate local pollution but have instead caused shortages. In addition, several states, including Pennsylvania and Maryland, have also asked for waivers. Where does this issue come from? In the 1990s, Congress passed several amendments to the Clean Air Act which included provisions designed to spur increased reliance on the cleaner-burning “reformulated” gasoline (RFG) as a way to Reformulated gasoline is now required by the Clean Air Act to be used in parts of the US that experience the worst smog, such as cities, while other areas may opt to implement RFG whether a problem exists or not. The Federal RFG program was introduced in 1995, and such fuel formulations are currently used in 17 states and the District of Columbia. About 30% of all gasoline currently sold in the US is composed of RFG. Each oil company prepares its own formula which must meet federal emission reduction standards. The regulations were implemented in two phases: the first was designed to reduce smog-causing agents by 64 000 tons per year in the states that use RFG, compared to conventional gasoline. This had the practical effect of eliminating the smog-forming emissions, according to the EPA, from over 10 million vehicles. The second phase of the program was designed to reduce smog pollutants by an additional 41 000 tons per year (equivalent to the removal of 16 million vehicles) in RFG areas. As an added benefit, the phases also reduced levels of the carcinogen benzene, a component of non-RFG gasoline. On May 3, 2006, the EPA announced that it was amending the RFG regulations to remove the oxygen content requirement. One amendment addressed the RFG oxygen requirement and related compliance requirements for gasoline sold in California. No negative comment was received regarding the California rule, which went into effect on April 24, 2006. The other rule, intended to remove the oxygen requirement for RFG in all other parts of the country, was challenged in the comment stage but became final on May 5, 2006. Meanwhile, formulation regulations were caught in the switch to ethanol during the gas shortage. Formulations of oxygenated gasoline, originally containing the since-removed additive MTBE, are currently switching to ethanol. Refiners had asked for a waiver from liability for the use of MTBE, but Congress refused, refiners cut its use, and Administrator Johnson has ruled out MTBE reintroduction. Ethanol, on the other hand, potentially has a bright future. “E 10”, the 10% blend commonly seen in many parts of the US, is the most well-known formulation that will assist in reducing the nations dependence on foreign oil. However, it is “E 85”, consisting of 15% gasoline and 85% ethanol that takes advantage of a renewable resource and burns cleaner in so-called “flex fuel” vehicles. Two wonderful ideas, without doubt, but detractors point out that ethanol, used since Henry Ford's earliest cars, isn't as efficient a fuel, and because demand outweighs supply, is currently more costly than gasoline. Currently, few E85 pumps are open, but more are promised. Given the sparse number of current suppliers, large-scale use of ethanol remains far away. Just 90 or so plants produce ethanol in this country, with about 25 more on the way. However, at best, ethanol will yield approximately 5 billion gallons per year by 2007. Compare that to the 140 billion gallons of gasoline that are currently consumed by US gas-guzzlers. In the meantime, therefore, waivers represent little more than a very short-term drop in the proverbial supply bucket. Thus, for the short term we will live without one pollution-helping oxygenate (MTBE) that causes severe pollution problems, while getting enamored with another (ethanol). It may not be the answer to those who want to drive their SUV cross-country at 75 mph out of the smog in time for Aunt Hattie's Fourth of July party in Scottsbluff. But me? I am pedaling my two-wheeler to the local fireworks supplier which, if nothing else, will be an exciting addition to the mid-summer haze. Douglass F Rohrman Lord, Bissell & Brook LLP, Chicago

Acupuncture Provides Short-Term Drop in High Blood Pressure

Acupuncture Provides Short-Term Drop in High Blood Pressure

Drop behaviour of random early detection with discrete-time batch Markovian arrival process

A matrix-analytic approach is applied to analyse both the long-term and the short-term drop behaviour of a router with an RED scheme. The bursty nature of packet drop is examined by means of conditional statistics with respect to alternating congested and non-congested periods. All of the four related performance measures are derived by conditional statistics, including the long-term drop probability, and the three short-term measures comprising average length of a congested period, average length of a non-congested period, and the conditional packet drop probability during a congested period.

Large and episodic decrease of water discharge from the Yangtze River to the sea during the dry season

A diagnostic study on the large and episodic decrease of discharge from the Yangtze River to the sea is presented. No trend has been detected so far in the time series of river flow recorded at Datong, but a large and short-term drop is evident through analysing the yearly minimum discharges. Water abstractions in the middle reach are evidently responsible for the large and episodic drop recorded at Datong. Downstream of Datong the discharge further decreases due to water abstraction by sluices and pumping stations, with a capacity comparable to the average discharge from Datong in dry months. Such large-scale water diversions may greatly reduce the water discharge into the sea during droughts, if countermeasures are not prepared. An increasing seasonal variability will exacerbate the existing water and environmental problems in the Yangtze Delta and estuary. An integrated management system is necessary for sustaining sufficient freshwater discharge into the sea.

Epidemiology of reproductive performance in dairy cows

The objectives of this presentation are to review results of our previous and on-going research with respect to the risk factors and consequences of poor reproductive performance in dairy cows, and to develop an economic framework to optimize decisions related to dairy cow reproductive performance. To make profitable breeding and replacement decisions, the farmer must account for factors including age, production level, lactation stage, pregnancy status, and disease history of the cows in the herd. Establishing the interrelationships among disease, milk yield, reproduction, and herd management is necessary for developing a decision model for disease treatment, insemination, and replacement. The data for the studies reviewed in this presentation incorporate health, production, and management components from Holsteins in the Northeast USA and Ayrshires from Finland. Data were analyzed using the Cornell Theory Center Supercomputer. The effect of risk factors on reproductive disorders was modeled with logistic regression, and on conception, insemination, and culling with survival analysis. The effect of reproductive disorders on milk yield was analyzed with mixed models. Economic optimization of reproductive performance was done with dynamic programming (DP). High milk yield, high parity, and calving in winter were risk factors for several reproductive disorders. These disorders, in turn, delayed insemination and conception in dairy cows, and some of them increased the risk of culling. Dystocia, retained placenta, and early metritis led to a short-term drop in milk production. High milk yield was not a major factor in delaying conception, except in first parity cows. However, higher yielders were more likely to be inseminated, and less likely to be culled. Non-pregnant cows had a higher risk of being culled. Reproductive performance of dairy cows influenced a herd's profitability, and good heat detection and conception rates provided opportunities for management control. It was not always economically advantageous to get cows pregnant as soon as possible, and there was no one optimal value for the calving interval length for all cows in a herd.

Seminal fluid regulation of female sexual attractiveness in Drosophila melanogaster.

Finding a willing and suitable mate is critical for sexual reproduction. Visual, auditory, and chemical cues aid in locating and/or attracting partners. After mating, females from many insect species become less attractive. This is caused by changes in the quantity and/or quality of pheromones synthesized by the female and to changes in the female's behavior. For example, female insects may stop releasing pheromones, assume a mate refusal posture, or move less in response to males. Many postmating changes in female insects are triggered by seminal fluid proteins from the male's accessory gland proteins (Acps) and by sperm. To determine the role of seminal fluid components in mediating changes in attractiveness, we measured the attractiveness of Drosophila melanogaster females that had been mated to genetically altered males that lack sperm and/or Acps. We found that the drop in female attractiveness occurs in two phases. A short-term drop in attractiveness is triggered independent of the receipt of sperm and Acps. Maintenance of lowered attractiveness is dependent upon sperm.

The b value before the 6th August, 1988 India-Myanmar Border Region Earthquake—a case study

Smith (1981, 1986) and Wyss et al. (1990) have observed that intermediate-term quiescence is often associated with an increasing b value. This study pertains to the temporal behaviour of the b value before the earthquake of 6th August, 1988, which occurred in the India-Myanmar border region. The b value in the preparation zone of the earthquake (21°–25.5°N, 93°–96°E), as identified by Gupta and Singh (1986, 1989), is found to have increased gradually from 1976 to a maximum value of 1.33 during July, 1987, followed by a short-term drop before the occurrence of the earthquake. The quiescence period observed by Gupta and Singh (1986, 1989) for this earthquake is better reflected by the intermediate-term increase in the b-value. A drop in the mean magnitude since 1978 is supported by a CUSUM plot.