How to let go: pectin and plant cell adhesion.

This is the final version of the article. It first appeared from Frontiers via http://dx.doi.org/10.3389/fpls.2015.00523Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell's life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such as organ abscission, dehiscence, and ripening. In these instances, the pectin-rich middle lamella must be actively altered to allow cell separation, a process which also requires cell wall modification. In this review, we will focus on the role of pectin and its modification in cell adhesion and separation. Recent insights gained in pectin gel mechanics will be discussed in relation to existing knowledge of pectin chemistry as it relates to cell adhesion. As a whole, we hope to begin defining the physical mechanisms behind a cells' ability to hang on, and how it lets go.The writing of this review was carried out with the help of grant BB-L002884-1 (BBSRC, UK)

Students’ Recognition of Function Transformations’ Themes Associated with the Algebraic Representation

The topic of function transformations is a difficult mathematical topic for school and college students. On the other hand, GeoGebra is a new technological tool for mathematics teaching and learning, so we wanted to experiment with this new tool in teaching non-basic function transformations to middle school students. Specifically, we wanted to examine how students conceive function transformations after working with GeoGebra, when this conceiving relates to the algebraic representation. The research participants were 19 ninth grade high achieving students who learned, with the help of GeoGebra translations, reflection and stretch. During their learning, the participants worked with transformations on the absolute function, the cubic function, and the quartic function. After they finished the transformation unit, the participants solved mathematics problems by means of function transformations. This research is interested in the participants’ solution of problems that included two non-basic functions: the absolute value of the quadratic function and the rationale function. The research findings show that the participants were generally able to solve successfully mathematical problems, by means of transformations on new and non-basic functions. Furthermore, the participants encountered difficulties in working with translations. These difficulties were due to the special algebraic form of the functions. We recommend that mathematics teachers expose middle school students to transformations on different types of non-basic function during learning this mathematical topic. Future researches could examine the impact of activities that include such functions and that are GeoGebra based on students’ conceptions and behavior when performing translations is involved

Water-Energy-Food Nexus Stakeholder Information Sharing and Engagement Workshop

On January 10, 2018, the Texas A&M University System Water-Energy-Food Initiative held the Water-Energy-Food Nexus Stakeholder Information Sharing and Engagement Workshop on the campus of Texas A&M University-San Antonio. The workshop involved over 70 stakeholders drawn from the water, energy, and food sectors in San Antonio and surrounding region. Stakeholders attending the workshop heard presentations on the status of San Antonio Case Study pilot projects and other WEF nexus work. Facilitated small-group sessions were held at the workshop to obtain stakeholder input on research questions to be asked, and on limitations and opportunities for stakeholder engagement on WEF nexus-related work in the San Antonio and the South Texas Region. Workshop participants also took before and after surveys to gauge knowledge about the WEF nexus. This report provides information on the outcomes of surveys, the workshop presentations and discussions, and the facilitated stakeholder sessions.https://digitalcommons.tamusa.edu/water_books/1002/thumbnail.jp

The Role of Popliteal Vein Incompetence in the Diagnosis of Saphenous-popliteal Reflux Using Continuous Wave Doppler

AbstractIntroduction: continuous wave Doppler (CWD) has good discriminatory power at the groin in the assessment of saphenous femoral junction (SFJ); however, it is not as accurate as duplex ultrasound scanning (DUS) in the popliteal fossa for assessment of saphenous popliteal junction (SPJ) in patients with primary short saphenous vein incompetence.Aim: the aim of this study was to compare the findings of CWD with those of DUS at the SPJ and assess the role of popliteal vein incompetence in the accuracy of CWD. Method: prospective study of consecutive patients presenting to a vein clinic requiring a duplex scan of their SPJ. Each patient was examined by one surgeon using CWD and by one radiologist using DUS. Each observer was unaware of the other's findings. Additional information on the competence of the popliteal vein on DUS was also recorded. Results: some 171 limbs in 128 patients with varicose veins were studied. One hundred and sixteen limbs had reflux at SPJ on CWD whilst 55 did not. Their mean age was 54 (range 18–85). Female to male ratio was 3:1. Spearman's rank correlation between CWD and DUS has 0.49 (p =0.0001). CWD has a sensitivity of 92% and specificity of 53% (PPV=62%, NPV=89%, accuracy=70%). Twenty-nine limbs had an incompetent popliteal vein (IPV). Of those, 12 limbs also had incompetence on CWD and competence on DUS at the SPJ, which represent 28% of the total number of limbs with these findings (n =43). Conclusion: CWD is sensitive in detecting incompetence at SPJ, though its specificity is low. In this study 17% (n =29) of all patients had incompetence of popliteal vein. Up to 25% ( n =12) of patients with SPJ incompetence on CWD (Doppler +) and competence on DUS (duplex −) had incompetence of the underlying popliteal vein, which may explain the low specificity. The presence of SPJ incompetence on CWD should be confirmed on DUS prior to surgery

Numbers of calling whales in the North Pacific

Since November 1995, the U. S. Navy's Sound Surveillance System (SOSUS) and other hydrophone arrays were used to regularly sample the occurance of whale sounds in the four regions bordering the continental margins across the North Pacific. The numbers of whales heard calling varied with the season and location for each species, Blue whales (Balaenoptera musculas), fin whales (Balaenoptera physalus), and humpback whales (Megaptera novaeangliae). For blue whales, calling during the fall season averaged 5 whales per event, winter averaged 1.5 whales per event, spring averaged 1 whale, and summer averaged 1.5 whales. For fin whales the number of whales heard ("F" calls from individuals) during winter averaged 3 whales per event, spring and fall calling averaged 1.5 whales, and summer averaged 1 whale. The "J" calling events, regardless of season, were judged to be from at least 6 fin whales. Humpback singing typically was from 3 whales. These numbers demonstrated seasonal variations in calling whales for each region.Funding was provided by CNO N45 Environmental Program and US Army Corps of Engineers (DCA87-00-H-0026) with funding from the Department of Defense Legacy Resource Management Program

Documentation for the CETACEA database of marine mammal literature references

This documentation for the CETACEA database of marine mammal literature references updates and expands the original work by Watkins, Bird, Moore, and Tyack 1988 (Reference Database Marine Mammal Literature, Technical Report WHOI-88-2). The CETACEA database is a comprehensive index of literature references used to file, store, search, retrieve, and format the data on marine animals. Organization of the references is complementary to features developed by William E. Schevill for his library of older cetacea literature, having direct association of species with over 300 indexed subjects, and with observation dates, locations, etc. This documentation describes the operation of the database (360 records), including indexing, sorting, and retrieval information developed though continued use of these systems. SPECIES and SUBJECT HEADING lists with their codes have been updated. Other databases have also developed around these indexing and sorting strategies to complement the CETACEA database, including databases of animal sounds for both the recordng data and the acoustic spectral information stored in libraries of digital sound cuts.Funding was provided by the Office of Naval Research through Contract Number N00014-88-K-0273

Distinctions in sound patterns of calls by killer whales (Orcinus Orca) from analysis of computer sound features

Calls of killer whales, Orcinus orca, were analyzed using computed sound features to classify sound patterns and identify call similarties. Calls were classified and separated according to the podfamily group within clans identified previously by John Ford (U. BC) in the Vancouver whale populations. Acoustic characteristics of the same call type from different individuals were extremely similar, so that discriminating these different sounds was the goal. The WHOI AcouStat program and associated database systems were used to define numerical statistics for each call, and then, these were compared to sort and classify the sounds. The results were in agreement with Ford's descriptions of the calls derived from visual inspection of sound spectrograms of calls. The classification analyses demonstrated that although specific shared calls from different killer whales were much alike, they could be sorted by the pod/subpod of the whales producing the calls. A typical analysis, for example, of the N4 call from Clan A (Vancouver, BC), classified 97% of the calls correctly according to the pod/family of the whales producing the calls. Remaining calls were variant, and likely a result of individual differences in call sounds. Similar classification analysis were tested on unsorted, unalyzed recordings from different populations of whales, and these too could be distinguished, with 98.5% correct separation of the calls

The Candida albicans Dse1 Protein Is Essential and Plays a Role in Cell Wall Rigidity, Biofilm Formation, and Virulence

The fungal pathogen Candida albicans is one of the leading causative agents of death in immunocompromised individuals. It harbors an arsenal of cell wall anchored factors that are implicated in virulence such as filamentation inducing factors, adhesins, lipases, proteases, and superoxide dismutases. Dse1 is a cell wall protein involved in cell wall metabolism. The purpose of this study is to characterize the role Dse1 plays in virulence. Dse1 appears to be an essential gene as no homozygous null mutant was possible. The heterozygote mutant exhibited increased susceptibility to calcofluor white, a cell wall disrupting agent, with a subsequent reduction in cell wall chitin content, decreased oxidative stress tolerance, a 30% reduction in biofilm formation, and a delay in adhesion that was mirrored by a reduction in virulence in a mouse model of infection. Dse1 thus appears to be an important protein involved in cell wall integrity and rigidity

THE ROLE OF QUALITATIVE SOCIAL POLICIES IN ACHIEVING THE HIGHEST INTERNATIONAL INDICATORS OF BALANCE AND SOCIAL ORGANIZATION

Purpose of the study: The study aimed to identify the role of qualitative social policies in achieving the highest international indicators in the degree of balance and social organization, by taking the UAE as a model in qualitative social policies; with expectations to eventually follow this model. Also, in light of current events, this model has a positive role in reducing the social chaos in many Arab and international countries. Methodology: The methodology of the qualitative analytical approach was used by returning to the statistical reports on indicators of the degree of integration and community organization in the United Arab Emirates United, the historical methodology of returning to documents, records and laws to identify the most prominent policies in the country. Main Findings: The study has concluded that social policy has a major role in achieving the highest degrees of integration and community organization. Applications of this study: The study also reached a set of recommendations, the most important of which were: the need to follow the qualitative social policies as in the model of the United Arab Emirates; and study the feasibility of applying those policies to societies that suffer from Anomie. Novelty/Originality of this study: No study has investigated the relationship between the social policies in the UAE and the international indicators of balance and social organization