Search

We recently characterized the competitive inhibition of cyclic AMP (cAMP) on three periplasmic acid phosphatases, AphAHi, NadNHi, and eP4 (HelHi), in Haemophilus influenzae Rd KW20. This inhibitory effect is vital for orchestrating the nutritional growth and competence development in KW20. Initially discovered in Escherichia coli, the function of AphA remains however obscure. This study investigates the regulation of E. coli aphA expression under nutrient starvation conditions. Using transcriptional reporters with truncated aphA promoter sequences, we found that starvations of carbon and phosphate, but not amino acid, stimulated aphA expression through distinct promoter regions. Deletions of crp or cyaA abolished aphA expression, confirming their crucial roles. Conversely, CytR deletion increased aphA expression, suggesting CytR's role as a repressor of aphA expression. Additionally, we extended the study of three other second messengers, i.e., cyclic GMP, cyclic UMP, and cyclic CMP, each sharing structural similarities with cAMP. Notably, cGMP competitively inhibits AphAHi's acid phosphatase activity akin to cAMP. In contrast, both cUMP and cCMP stimulate AphAHi's phosphatase activity in a concentration dependent manner. Collectively, these data imply a complicated connection between nucleotide metabolism, AphA, cyclic purine and pyrimidine nucleotides in bacterial nutrient uptake and natural competence.

Polar Lows (PLs) are intense maritime meso‐scale cyclones that form over cold ocean regions in high latitudes. They affect the weather and climate of Antarctica and the surrounding ocean by producing storms with near or above gale‐force winds and heavy precipitation. This study investigated PLs in the Southern Ocean (SO) between 60 and 85°S from 2000 to 2020, using a tracking algorithm applied to the ERA5, CCMP, and NCEP/NCAR data sets. The results showed that PLs are most frequent in winter (JJA) and least frequent in summer (DJF), with a maximum in 2018 and a minimum in 2014. The results also show that PLs are concentrated over the Antarctic Circumpolar Current (ACC) region, along the Ross Sea, the Amundsen Sea, and the Bellingshausen Sea from April to October. These regions have strong thermal gradients and orographic forcing that enhance cyclogenesis. Our research reveals that there were 1,073 occurrences of PLs during the study period, with an average 51 cases per year. The study also explored the influence of sea surface temperature anomalies, sea surface currents, and MCAOs Index on PL genesis. The Amundsen‐Bellingshausen Seas Low (ABSL) and Pacific Ocean currents have a considerable effect on PLs developing in the SO. This research provides valuable information on PLs in the SO, which are poorly observed and understood. However, more research is required to understand how these phenomena are evolving in the present, and how they will change in the future. Plain Language Summary: We investigated polar lows, which are intense maritime storms that develop over cold ocean regions, at high latitudes with high winds and heavy precipitation. We used different data sources to find out when and where these storms occurred in the Southern Ocean from 2000 to 2020. We found out that there were more than 1,000 storms in those 21 years, with about 51 storms each year. These storms mostly developed in the winter of the Southern Hemisphere and concentrated over the Antarctic Circumpolar Current region, along the Ross Sea, the Amundsen Sea, and the Bellingshausen Sea from April to October. These regions have large thermal gradients and orographic forcing that favor cyclogenesis. We found that the Amundsen‐Bellingshausen Seas Low and Pacific Ocean currents have a substantial effect on polar low formation in the Southern Ocean. Our study helps us know more about these maritime meso‐scale cyclones, which are hard to observe and study. Key Points: Present study identified PLs in the SO from 2000 to 2020, using a tracking algorithm applied to ERA5, CCMP, and NCEP/NCAR data setsPLs are concentrated over the ACC region, along the Ross, the Amundsen, and the Bellingshausen Sea from April to OctoberThe ABSL and Pacific Ocean currents can have an considerable impact on PL activity in the region [ABSTRACT FROM AUTHOR]

We recently characterized the competitive inhibition of cyclic AMP (cAMP) on three periplasmic acid phosphatases, AphA Hi , NadN Hi , and eP4 (Hel Hi ), in Haemophilus influenzae Rd KW20. This inhibitory effect is vital for orchestrating the nutritional growth and competence development in KW20. Initially discovered in Escherichia coli , the function of AphA remains however obscure. This study investigates the regulation of E. coli aphA expression under nutrient starvation conditions. Using transcriptional reporters with truncated aphA promoter sequences, we found that starvations of carbon and phosphate, but not amino acid, stimulated aphA expression through distinct promoter regions. Deletions of crp or cyaA abolished aphA expression, confirming their crucial roles. Conversely, CytR deletion increased aphA expression, suggesting CytR's role as a repressor of aphA 's acid phosphatase activity akin to cAMP. In contrast, both cUMP and cCMP stimulate AphA Hi 's acid phosphatase activity akin to cAMP. In contrast, both cUMP and cCMP stimulate AphA Hi 's phosphatase activity in a concentration dependent manner. Collectively, these data imply a complicated connection between nucleotide metabolism, AphA, cyclic purine and pyrimidine nucleotides in bacterial nutrient uptake and natural competence., Competing Interests: No conflict of interest is relevant with the contents of this article.

Wind and waves are important factors affecting the safety of the wind power supporting structure of offshore wind farms. In order to determine the design waves of an offshore wind farm in Rudong, the atmospheric model WRF were adopted to simulate the process of tropical storm and joint CCMP wind field data set as a drive wind field, by which the SWAN model was used to simulate the wave process in the sea area of Rudong wind farm in the past 20 years. The wind speed and wave elements in different return periods were obtained. The results show that the combination of WRF simulated tropical storm results and CCMP wind field can obtain more accurate wind field and more reasonable calculated wave results. [ABSTRACT FROM AUTHOR]

cCMP and cUMP have been identified in numerous biological systems and proposed to serve as second messengers. However, this proposal remained controversial because of the base-promiscuity of generators, effectors, phosphodiesterases, and bacterial toxins. With the identification of specific cytidylyl and uridylyl cyclases, cCMP and cUMP research enters a new era. [ABSTRACT FROM AUTHOR]

In 2013, the Odisha state Vector Borne Disease Control Programme led a five year operational research project, under programmatic conditions, in close collaboration with several partners. This Comprehensive Case Management Project covered a population of 900,000 across paired control and intervention blocks in four districts, each with different transmission intensities. Key gaps in access to malaria services were identified through household surveys and a detailed situation analysis. The interventions included ensuring adequate stocks of rapid diagnostic tests and antimalarial drugs at the village level, the capacity building of health workers and ASHAs, setting up microscopy centres at the primary health care level, and conducting mass screening and treatment in poorly accessible areas. The programme strengthened the routine health system, and improved malaria surveillance as well as the access to and quality of care. Initially, the programme led to increased case reporting due to improved detection, followed by a decline in malaria incidence. Lessons from the project were then scaled up statewide in the form of a new initiative—Durgama Anchalare Malaria Nirakaran (DAMaN).

Based on the third-generation wave observation model WAVEWATCH-III, CCMP and ERA wind fields were respectively used as driving fields to conduct numerical simulation, validity test and wave analysis of effective wave height caused by typhoon "rainbow" in the South China Sea in October 2015. The study found that: three typhoon track points in the South China Sea are selected for parameter test. By comparing the simulated wave height with the measured wave height, the correlation coefficient of ERA wind field is 0.867~0.932, the correlation coefficient of CCMP wind field is 0.871~0.901, and the absolute deviation value of the two wind fields is 0.043~0.347 m. The effective wave height diagram of wind field simulation was made, and it was found that the simulation effect of the two wind fields is better. The typhoon mainly affected the northwest of the Philippines islands in the east, the Taiwan Strait in the north, and the Beibu Gulf sea area in the west. The maximum wave height of the coastal waters during the typhoon period is over 9 m. [ABSTRACT FROM AUTHOR]

Wind power on oceanic near‐inertial oscillations is thought to play an important role in furnishing the diapycnal mixing in the ocean. Yet their global distribution and magnitude have not been quantified based on observations. In this study, we use hourly ocean current records derived from surface drifters to compute the global near‐inertial wind power during 1993–2016, with a combination of surface wind measurements obtained from satellites. The climatological near‐inertial wind power integrated between 60°S and 60°N is estimated to be 0.3–0.6 TW. The strongest energy flux occurs in the 30–60° latitude band during the winter season as a result of energetic storm activities. Ocean current imprint on wind stress has a significant impact on the estimated global near‐inertial wind power from drifters. Neglecting this imprint overestimates the near‐inertial wind power locally by 25–120% and its global mean value by 60%. Plain Language Summary: Wind stress fluctuations in the near‐inertial band can resonantly force near‐inertial oscillations (NIOs) in the surface mixed layer. These wind‐generated NIOs radiate downwards into the ocean interior, transfer their energy to small scales, and eventually break, providing energy to furnish the diapycnal turbulent mixing in the thermocline and deep ocean. In the past two decades, the global near‐inertial wind power has been extensively studied based on numerical models. However, the estimated values differ significantly (0.3–1.5 TW) among studies. Such a great range throws doubts on the validity of the model simulated near‐inertial wind power. It also causes uncertainties in the contribution of NIOs to diapycnal turbulent mixing and their parametrizations in ocean general circulation models. Therefore, it is essential to obtain a benchmark for global near‐inertial wind power based on observations. In this study, we evaluate the global near‐inertial wind power based on drifters and satellite‐measured winds. The climatological near‐inertial wind power integrated between 60°S and 60°N is estimated to be 0.3–0.6 TW. It is found that the ocean current imprint on wind stress has a significant impact on the estimated near‐inertial wind power. Neglecting this imprint leads to overestimation of near‐inertial wind power globally by 60% and locally by 25–120%. Key Points: The climatological near‐inertial wind power integrated between 60 degrees south and 60 degrees north is estimated to be 0.3‐0.6 TWNeglecting ocean current imprint on wind stress overestimates the near‐inertial wind power [ABSTRACT FROM AUTHOR]

The hyperpolarization‐activated cyclic‐nucleotide‐gated (HCN) ion channels control nerve impulse transmission and cardiac pacemaker activity. The modulation by cAMP is critical for the regulatory function of HCN in both neurons and cardiomyocytes, but the underlying mechanism is not fully understood. Here, we show how the structure of the apo cAMP‐binding domain of the HCN4 isoform has contributed to a model for the cAMP‐dependent modulation of the HCN ion‐channel. This model recapitulates the structural and dynamical changes that occur along the thermodynamic cycle arising from the coupling of cAMP‐binding and HCN self‐association equilibria. The proposed model addresses some of the questions previously open about the auto‐inhibition of HCN and its cAMP‐induced activation, while opening new opportunities for selectively targeting HCN through allosteric ligands. A remaining challenge is the investigation of HCN dimers and their regulatory role. Overcoming this challenge will require the integration of crystallography, cryo electron microscopy, NMR, electrophysiology and simulations. [ABSTRACT FROM AUTHOR]

Interest in Colombia’s offshore industry has increased over the past years. Therefore a detailed characterization of extreme wind and waves, in terms of return periods, numbers of events and its duration during the annual cycle, is needed. Two sets of high-resolution data are used in the statistical extreme value analysis (EVA). The significant wave height data (0.125°, 6 h) are from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis available for the past 35 years (1979–2014). Surface winds (0.25°, 6 h) from the Cross-Calibrated Multi-Platform Ocean Surface Wind Vector Analyses (CCMP) of NASA/GSFC/NOAA (NASA/Goddard Space Flight Center/National Oceanic and Atmospheric Administration) are available for the past 24 years (1987–2011). Three well-known methods are applied to the data: the Block Maxima (BM), the Peak-Over-Threshold (POT) and the Method of Independent Storm (MIS). Several probabilistic models (Gumbel, Generalized Extreme Value, Weibull and Pareto) are evaluated for the BM and different threshold values for the POT and MIS. The results show that waves can reach up to 3.8 m and winds can be as strong as 31 m/s when considering the 50–100-year return periods. However, the wave model could underestimate values by up to one meter; hence, there is a probability of higher values in the region. Seasonally, most extreme events occur during the dry season (December–March) and during the Mid-Summer-Drought (MDS) or Veranillo months (June–July). Local conditions, including the reinforcement of the Caribbean Low Level Jet (CLLJ) and the occurrence of cold atmospheric fronts, are important drivers of extreme metoceanic variability. The total number of extreme wind events varied spatially and temporally from 15 to 65 and the mean duration from 15 to 25 h. A total number of extreme wave events ranging from <10 to 80 were computed during the annual cycle in the areas of interest, with a mean duration of less than 40 h. [ABSTRACT FROM AUTHOR]

The seasonal and diurnal cycles of ocean vector winds in the domain of the South China Sea are characterized and compared using RapidScat and the Cross-Calibrated Multi-Platform (CCMP) data sets. Broad agreement in seasonal flow patterns exists between these data sets during the year 2015. Both observe the dramatic reversal from wintertime trade winds (November-April) to westerly flow associated with the summer monsoon (May-October). These seasonal changes have strong but not equivalent effects on mean wind divergence patterns in both data sets. Specifically near the Philippines, the data sets agree on several aspects of the seasonal mean and diurnal cycle of near-surface vector winds and divergence. In particular, RapidScat and CCMP agree that daytime onshore and nocturnal offshore flow patterns affect the diurnal cycle of winds up to ~200 km west of Luzon, Philippines. Observed disagreements over the diurnal cycle are explainable by measurement uncertainty, as well as shortcomings in both data sets. [ABSTRACT FROM AUTHOR]

The third-generation wave model, WAVEWATCH III, was employed to simulate bulk wave parameters in the Persian Gulf using three different wind sources: ERA-Interim, CCMP, and GFS-Analysis. Different formulations for whitecapping term and the energy transfer from wind to wave were used, namely the Tolman and Chalikov (J Phys Oceanogr 26:497-518, 1996), WAM cycle 4 (BJA and WAM4), and Ardhuin et al. (J Phys Oceanogr 40(9):1917-1941, 2010) (TEST405 and TEST451 parameterizations) source term packages. The obtained results from numerical simulations were compared to altimeter-derived significant wave heights and measured wave parameters at two stations in the northern part of the Persian Gulf through statistical indicators and the Taylor diagram. Comparison of the bulk wave parameters with measured values showed underestimation of wave height using all wind sources. However, the performance of the model was best when GFS-Analysis wind data were used. In general, when wind veering from southeast to northwest occurred, and wind speed was high during the rotation, the model underestimation of wave height was severe. Except for the Tolman and Chalikov (J Phys Oceanogr 26:497-518, 1996) source term package, which severely underestimated the bulk wave parameters during stormy condition, the performances of other formulations were practically similar. However, in terms of statistics, the Ardhuin et al. (J Phys Oceanogr 40(9):1917-1941, 2010) source terms with TEST405 parameterization were the most successful formulation in the Persian Gulf when compared to in situ and altimeter-derived observations. [ABSTRACT FROM AUTHOR]

CCMP(centralized conferencing manipulation protocol) enables adding and removing conference participants, changing their roles, adding and removing media streams in conference system. In this paper, by using extended CCMP, a new distributed conference system architecture which can be used to multiple servers distributed conference system in SIP(session initiation protocol) environment has been presented. In this study, according to increasing number of participants, a new extended CCMP architecture which can distribute conference system loads to multiple servers dynamically to decrease loads of servers has been designed. This extended CCMP architecture also can add dynamically new servers from the prepared servers pool. Furthermore, new conference information data format which can represent extended CCMP has been designed, and exchange procedures of extended CCMP control messages which can distribute loads between servers have also been presented. The performance of the proposed system has been analysed by simulation. [ABSTRACT FROM AUTHOR]

This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards: WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnera-bilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educational simulation tool written in C++ Builder for facilitating the unders-tanding of this protocol at academic level. Two practical cases of wireless security configurations using Cisco net-working equipment are also presented: configuring and enabling WPA-Personal and WPA2-Personal (these being security options used by TKIP and AES, respectively).

The cyclic purine nucleotides cAMP and cGMP are established second messengers. By contrast, the existence of the cyclic pyrimidine nucleotides cytidine 3′,5′-cyclic monophosphate (cCMP) and uridine 3′,5′-cyclic monophosphate (cUMP) has been controversial for decades. The recent development of highly sensitive mass spectrometry (MS) methods allowed precise quantitation and unequivocal identification of cCMP and cUMP in cells. Importantly, cCMP and cUMP generators, effectors, cleaving enzymes, and transporters have now been identified. Here, I discuss evidence in support of cCMP and cUMP as bona fide second messengers, the emerging therapeutic implications of cCMP and cUMP signaling, and important unresolved questions for this field. [ABSTRACT FROM AUTHOR]

In addition to the well-known second messengers cAMP and cGMP, mammalian cells contain the cyclic pyrimidine nucleotides cCMP and cUMP. The Pseudomonas aeruginosa toxin ExoY massively increases cGMP and cUMP in cells, whereas the Bordetella pertussis toxin CyaA increases cAMP and, to a lesser extent, cCMP. To mimic and dissect toxin effects, we synthesized cNMP-acetoxymethylesters as prodrugs. cNMP-AMs rapidly and effectively released the corresponding cNMP in cells. The combination of cGMP-AM plus cUMP-AM mimicked cytotoxicity of ExoY. cUMP-AM and cGMP-AM differentially activated gene expression. Certain cCMP and cUMP effects were independent of the known cNMP effectors protein kinases A and G and guanine nucleotide exchange factor Epac. In conclusion, cNMP-AMs are useful tools to mimic and dissect bacterial nucleotidyl cyclase toxin effects. [ABSTRACT FROM AUTHOR]

Argemone mexicana Lin. (diploid having bright yellow flowers) and Argemone ochroleuca ssp. ochroleuca (tetraploid having white flowers) were sampled along with some plants having lemon color flowers (LCF). The latter had very few flowers, and anthers with sterile pollen grains. Flow cytometric analysis of DNA content in all the plants was conducted to identify their ploidy level. The mean value of the peaks varied for mexicana (95.05), ochroleuca (176.88) and LCF ( 142.88) plants. Genetic variation (parentage and relationship) was assessed in the species with white, yellow and LCF plants using 100 random amplified polymorphic DNA (RAPD), 94 inter simple sequence repeat (ISSR) and 10 consensus chloroplast microsatellite primers(CCMP). Molecular analysis and ploidy analyses confirmed the hybridity of naturally occurring LCF plants. The CCMP3 primer disclosed polymorphism among the parents and unequivocally established that A. ochroleuca is the maternal parent of the LCF plant. [ABSTRACT FROM AUTHOR]

To differentiate the taxa at the specific and varietals levels a range of DNA fingerprinting techniques are being employed. The objective of the current study was to establish the genetic correlation between the morphologically comparable two Melilotus species i.e. Melilotus indica and M. alba by using five RAPD and ten CCMPs. The percentage polymorphism between the two studied species was 33.33 indicating that they are intimately related and symbolize novel incongruity. Owing to less significant level of genetic variation, detected through RAPD and CCMP, the differences between the two species could be attributed to gene mutation or minor chromosomal alterations. [ABSTRACT FROM AUTHOR]

Abstract: The cyclic purine nucleotides cAMP and cGMP are well-characterized second messengers and activators of PKA and PKG, respectively. In contrast, the functions of the cyclic pyrimidine nucleotides cCMP and cUMP are poorly understood. cCMP induces relaxation of smooth muscle via PKGI, and phosphodiesterases differentially hydrolyze cNMPs. Here, we report that cNMPs differentially activate PKA isoforms and PKGIα. The combination of cCMP with cAMP reduced the EC50 of cAMP for PKA. PKGIα exhibited higher specificity for the cognate cNMP than PKA. Our data support a role of cCMP and cUMP as second messengers. [Copyright &y& Elsevier]

Abstract: We analysed the function and intracellular signalling of the cyclic pyrimidinic nucleotide cCMP. The membrane-permeable cCMP analogue dibutyryl-cCMP mediated mouse aorta relaxation. cCMP activated purified cGMP-dependent protein kinase (cGK) Iα and Iβ and stimulated cGK in aorta lysates. cCMP-induced relaxation was abolished in cGKI-knockout tissue. Additionally, deletion of inositol–trisphosphate receptor associated cGKI substrate (IRAG) suppressed cCMP-mediated relaxation. Signalling of cCMP via cGKI/IRAG appears to be of broader physiological importance because cCMP-mediated inhibition of platelet aggregation was absent in cGKI- and IRAG-deficient platelets. These results demonstrate that cCMP acts as intracellular messenger molecule, most unexpectedly utilizing the cGMP signal transduction pathway. [ABSTRACT FROM AUTHOR]

As a maritime nation, Canada is the home to high-quality offshore wind resources. The assessment of Canada's offshore wind resources has a strategic significance for realizing its low-carbon future. This study focused on high-resolution and high-accuracy estimates of offshore wind resources over Canada using satellite-derived wind maps, e.g., CCMP (Cross-Calibrated Multi-Platform) images from 1988 to 2017. The CCMP derived wind speed and density were bias-corrected by ocean surface wind measurements collected from 63 stations located along the seas/lakes in Canada from 1987 to 2018. A series of consistent offshore wind resource maps were produced and analyzed. The results generated from CCMP were then compared with previous assessment (i.e., Environment and Climate Change Canada (ECCC)'s Wind Atlas) and proved to perform better in simulating wind speeds. We estimated the technically available offshore wind area, gross power capacity and gross potential over Canada. For example, a gross potential production of 20.348, 20.441, and 20.376 PWh/year were calculated using three commercial offshore wind turbines, i.e. GE 3.6s, REpower 5 M, and V164–8.0 over the calculated total gross offshore area of 1.053 million km2. It far exceeds the Canada's electricity consumption (i.e., 0.641 PWh) in 2018. In addition, most of the potential power productions are distributed in the Canadian Atlantic and Pacific Oceans, Hudson Bay and St Lawrence, with the mean wind speeds increasing from 1988 to 2017. This study can help to assess offshore wind resources and provide decision-makers with some scientific evidences for developing offshore wind in Canada. • Canada's offshore wind energy is assessed using buoy-measurement-based bias-corrected CCMP. • The assessment provides wind speed, power density, and potential at high resolution & accuracy. • Offshore wind power production far exceeds Canada's power consumption (0.64 PWh in 2018). • The production is the highest in Atlantic & Pacific Oceans, Hudson Bay, and St Lawrence. • We build one basis for Canadian energy systems planning (e.g., renewables for carbon neutrality). [ABSTRACT FROM AUTHOR]