Ajuga Orientalis L Anatomy Studies

Ajuga Orientalis L Anatomy Studies The anatomical studies of medicinal taxon Ajuga orientalis L. (Lamiaceae) from Turkey Abstract. Ajuga orientalis[a1], with a wide distribution area in Turkey, is traditionally used medicine in the treatment of some skin diseases in Anatolia. The aim of this study is to determine the anatomical characteristics of the root[a2], leaf, petiole, calyx and corolla of medicinal taxon [a3]A. orientalis in cross sections. As a result of the study, it was found that the pith rays of root are composed 3-4 rowed cells and stem was quadrangular[a4]. There were glandular and non-glandular hairs on the surface layers on stem, leaves, petiole, calyx and corolla. Starch particles were also identified[a5] in the cortex cells of stem. The stomata were diastic[a6] and the leaf was bifacial. There were one big vascular bundle in the center and 4-5 small vascular bundles on each corner of the petiole. It was also determined that adaxial epidermis cell shapes of corolla are papillose type. Key words: Ajuga orientalis, anatomy, medicinal plant, Turkey INTRODUCTION The Lamiaceae is a large family showing natural distribution. Most of species belonging to this family are shrubby and herbaceus, and trees are extremely rare (Heywood, 1978). The family with its more than 250 genera and approximately 7000 species, has a cosmopolitan distribution (Thorne, 1992). According to BaÃ…Å ¸er (1993), Turkey is accepted as a gene center for this family. Many species of this family are aromatic and are often used as herb spices, folk medicines and fragrances (Werker et al., 1985). With their pleasant fragrance, many species of Lamiaceae have been used as herbal teas in Turkey. Many of species are used as raw material in the cosmetic industry. Some species are traditionally used as medicinal plants (Baytop, 1984). It was reported that some Ajuga L. and Salvia L. species are cultivated as ornamental plants (Baytop, 1984; Ãâ€"zdemir and Ã…Å ¾enel, 2001; Akà §in et al., 2006). In addition to this, Lamiaceae has great importance due to its economical valu e and its variety of species. The genus Ajuga L. belongs to Lamiaceae family. Ajuga L. is represented in Turkey by 13 species and 22 taxa, six species and one subspecies being endemic (Davis et al., 1982-1988). Ajuga species are used in folk medicine in different parts of the world for the treatment of rheumatism, gout, asthma, diabetes, malaria, ulcers and diarrhea and have antibacterial, antitumor, antifeedant, and vulnerary properties (Chen et al., 1996; Ben Jannet et al., 2000). Baytop (1999) reported that some Ajuga species generally known as â€Å"mayasÄ ±l otu† in Turkey have been widely used for their aromatic, diuretic, antipyretic, tonic, diaphoretic, astringent, bitter and homeopathic properties in the Turkish folk medicine. Ajuga orientalis L. one of the species of Ajuga genus is used against some skin diseases by hug on the skin in Anatolia (Koyuncu et al., 2010). Although many species of Lamiaceae family are investigated anatomically (ÇobanoÄÅ ¸lu, 1988; Uysal et al., 1991; Ãâ€"zdemir and Altan, 2005; AktaÃ…Å ¸ et al., 2009) there is no anatomical study of A. orientalis L. in literature. Due to its medicinal importance mentioned above in this study, the purpose of this study is to determine the anatomical characteristics of A. orientalis L. MATERIALS AND MEDHODS In the present study, the plant specimens of A. orientalis were collected during the flowering period and natural populations in A5 Amasya (in the vicinity of Direkli village, open areas, at 1800 m, June 2012, Ä °Ãƒâ€"ztà ¼rk ÇalÄ ± 461) which is a city in the Black Sea region of Turkey. Its taxonomical description was carried out according to Davis (1982). Anatomical investigations were performed using an average of fresh specimens kept in 70% alcohol. Cross sections of root, stem, laeve, petiole, calyx and corolla were taken from 30 specimens of A. orientalis and 50 measurements were conducted for each parameter. Transverse sections were made by hand using commercial razor blades and stained with Sartur reactive (ÇelebioÄÅ ¸lu and Baytop, 1949). Measurements in the sections were performed under a Leica ICC50 HD binocular light microscope by using a Leica Digital Camera and objectives used were x10 and x40. Photographs were taken with a Leica ICC50 HD binocular light microscope and a Leica Digital Camera. RESULTS In cross-sections taken from the root, stem, leaf, petiole, calyx and corolla of A. orientalis , the following significant properties were observed below. In the transverse section of the root, there was a periderm which was the outermost layer of the root of A. orientalis (Figure 1). The periderm had 8-9 layers. The dimensions of periderm cells were 15 – 60 X 15 – 57.5  µm (Table 1). Beneath the periderm, there was the multi-layered cortex, composed of ovaidal and parancyhmatic cells. The cortex was 9-10 layers. The cambium, composed of 3-4 layered, was located between the xylem and the phloem. Beneath the cambium, there were xylem tissue (7.5 – 15 X 7.5 – 20  µm) composed of regular trachea and tracheid cells. Xylem cells were also present in the center, so the pith is not seen in the center. There were 3-4 layered primary pith rays between the secondary xylem cells. A. orientalis, as a typical characteristic of the Lamiaceae, had a 4-angle stem. Its epidermis usually had one layer composed of ovoidal cells (12.5 – 42.5 X 17.5 – 50  µm). The upper surface was covered with a cuticle (1.25 – 2.5  µm). There were glandular and non-glandular hairs on the epidermis (Figure 2). Transverse section of the stem revealed 9-10 layered collenchyma placed on the corners. The cortex was composed of 6-7 layered paranchymatous cell. The dimensions of paranchymatous cells were 27.5 – 75 X 15 – 55  µm (Table 1). Starch particles were also observed in the paranchymatous cells of stem (Figure 3). There were 2-3 layers of sclerenchyma in the outer side of phloem. Right beneath the phloem, there was a 1-2 rowed cambium layer. The xylem tissue existing beneath the cambium was composed of regular trachea and tracheid cells. The vascular bundles were bigger on the corner than other parts of stem. Between the corners there were als o numerous small bundles in the A. orientalis stem. The vascular bundles were collateral (Figure 2). The pith was wide and consist of flat cells with intercellular spaces. There was a cavity in the centre of the pith. In the leaves, the epidermis was single layered on upper and lower surface. There were glandular and non-glandular hairs on epidermis. The cuticle was 2.5 – 5  µm thick. Just beneath the upper epidermis cells, there were 2-3 rowed palisade parenchyma cells (Figure 5). The dimensions of the palisade parenchyma cells were 12.5 – 25 X 25 – 50  µm (Table 1). The 2-3 rowed spongy parenchyma existed beneath the palisade. The spongy parenchyma covered less space than does the palisade parenchyma. The collateral vascular bundle was located in the midrib region (Figure 5). There were sclerenchyma cells in the outer side of phloem. All vascular bundles in the leaves were surrounded by bundle sheet cells. The stoma was diastic and the leaf was bifacial (Figure 4 and Figure 5). The stoma presented on upper and lower surfaces of the leaf (Figure 4). Both adaxial and abaxial epidermis cells were single layered in the petiole (Figure 6). The dimensions of the adaxial epidermis cell were 15 – 45 X 17.5 – 27.5  µm while those of the abaxial epidermis one were12.5 – 27.5 X 15 – 17.5  µm (Table 1). There were a lot of glandular and non-glandular hairs on epidermal cells which were ovoidal-rectangular shapes. Parenchymatic cortex cells were 10-11 layered. There was one big vascular bundle in the center and 4-5 small vascular bundles at each corners of petiole. The vascular bundles were surrounded by sclerenchymatic cells (Figure 6). There were parenchmatic bundle sheets on the all vascular bundles. The type of vascular bundle was collateral (Figure 6). There were 2-3 layered collenchyma in the area between the corners. In the calyx, the adaxial epidermis cells were smaller than abaxial epidermis cells. The dimensions of adaxial cuticle were 1.25 – 2.5  µm whereas the those of the abaxial cuticle is 2.5 – 3.75  µm (Table 1). Parenchymatic cells were flat ovoidal. There were glandular and non-glandular hairs on the epidermis (Figure 7a). In the cross-section of corolla, cuticle was present on both abaxial and adaxial epidermis cells covered by glandular and non-glandular hairs. The shapes of adaxial epidermis cells were papillose type (Figure 8). Beneath the adaxial epidermis, there were the parenchyma cells with intercellular spaces (Figure 7b). There was a vascular bundle in the midrib. DISCUSSION The present study provided useful information on the anatomy of A. orientalis. Few studies on the species A. orientalis had been found in literature (Sajjadi and Ghannadi, 2004; Koyuncu et al., 2010). But, the measurements and observation of anatomical characters belonging to the medicinal taxon A. orientalis were reported for the first time in the present paper. Metcalfe and Chalk (1972) determined some imported anatomical information about root anatomy of Lamiaceae family. They stated that the pith rays of roots of the family are 2-12 or more rowed cells. It was found that the pith rays of A. orientalis were composed 3-4 rowed cells. These findings were consistent with those of Metcalfe and Chalk (1972) and those of some studied species of Lamiaceae (Baran and Ãâ€"zdemir, 2006; Ãâ€"zkan and Soy, 2007; Baran and Ãâ€"zdemir, 2009). Metcalfe and Chalk (1972) also stated that the members of Lamiaceae family have quadrangular with well-defined collenchyma in the four angles and scleranchymatous tissue surrounds the phloem groups of vascular bundles. In the transverse section of A. orientalis, the stem of this species was quadrangular with well-defined collenchyma in the four angles. It was also determined that there were 2-3 layers of sclerenchyma in the outer side of phloem in this study. Quadrangular stem with well-defined collenchyma in th e four angles and scleranchymatous tissue surrounds the phloem groups of vascular bundles were observed in other members of Lamiaceae family (Metcalfe and Chalk, 1972; Kandemir, 2003; Baran and Ãâ€"zdemir, 2006; Kahraman et al., 2010). The vascular cambium located between the phloem and the xylem was 1-2 rowed layer in the stem of A. orientalis. The vascular cambium was seen in the cross-sections of other members of Lamiaceae family (Dinà § and Ãâ€"ztà ¼rk, 2008; Baran and Ãâ€"zdemir, 2009). There were big vascular bundles on the corners of A. orientalis stem whereas a lot of small bundles between the corners were observed in the present study. There were also starch particles in the paranchymatous cortex cells of stem. The leaf of A. orientalis had 2-3 layered palisade parenchyma and 2-3 layered spongy parenchyma cells. Baran and Ãâ€"zdemir (2009) also stated that Lamium lycium which is the member of Lamiaceae family has 2-3 layered palisade parenchyma and 2-3 layered spongy parenchyma cells as well. These results were parallel to our results mentioned above. On the other hand, the stoma type of A. orientalis was diasitic and the leaf was bifacial. According to Metcalfe and Chalk (1972), diasitic stoma type was most common in Lamiaceae family. Diasitic stoma and bifacial mesophyll type were also observed on the leaf of Ajuga chamaepitys and Ajuga reptans (Akà §in et al., 2006). The stomata were observed on both upper and lower surfaces of the leaf. Metcalfe and Chalk (1972) stated that the structure of the vascular bundles in the petiole of the species in the Lamiaceae could be used as a diagnostic character. The structure of petiole shows differences between genera and species. In addition to this, useful petiole anatomical characters are determined in designated taxonomical structures of some species (Shaheen, 2007; Eric et al., 2007). In the petiole of A. orientalis, there was one big vascular bundle in the center and 4-5 small vascular bundles at e ach corner of the petiole. Akà §in et al. (2011) found that Ajuga reptans has a total of nine vascular bundles: one big bundle in the middle and 4 vascular bundles at each corner. The vascular bundles of leaf were surrounded by sclerenchymatic cells. Collenchyma in the petiole is 2-3 layered at the each corners. In the cross-section of calyx and corolla, both adaxial and abaxial epidermis cells were covered with cuticle. In addition to this, there were a vascular bundle in the midrib of calyx and corolla. The adaxial epidermis cells of corolla were papillose type. The most distinguishing characteristics of the species in the anatomical structure were the presence of glandular hairs on the surface layers on stem, leaves, petiole, calyx and corolla. Like other other members of the Lamiaceae, A. orientalis had both glandular as well as non-glandular trichomes. Glandular trichomes were mainly observed on calyx and corolla, but non-glandular ones were found on the stem, leaf surface and petiole. According to Metcalfe and Chalk (1972), having glandular and non-glandular trichomes are important anatomical characters. Glandular trichomes significant taxonomic character and act imported role for pollination in the Lamiaceae family (Navarro and El Oualidi, 2000). As a result, anatomical characters of medicinal taxon A. orientalis were studied for the first time in this paper. According to the results mentioned above, the anatomical features of root, stem, leaf, petiole, calyx and corolla provided useful characteristics for distinguishing species in Ajug a genus. REFERENCES Akà §in OE, Ã…Å ¾enel G, Akà §in Y (2006). The morphological and anatomical properties of Ajuga reptans L., and Ajuga chamaepitys (L.) Schreber subsp. chia (Schreber) Arcangel. var. chia (Lamiaceae) taxa. Pak. J. of Biol. Sci. 9(2): 289-293. Akà §in Ãâ€"E, Ãâ€"zyurt MS, Ã…Å ¾enel G (2011). Petiole anatomy of some Lamiaceae taxa.Pak. J. Bot. 43(3): 1437-1443. AktaÃ…Å ¸ K, Ãâ€"zdemir C, Ãâ€"zkan M, Akyol Y, Baran P (2009). Morphological and anatomical characteristics of Salvia tchihatcheffii endemic to Turkey. Afr. J. Biotechnol. 8(18): 4519-4528. Baran P, Ãâ€"zdemir C (2006). The morphological and anatomical characters of Salvia napifolia Jacq., in Turkey. Bangladesh J. Bot. 35(1): 77-84. Baran P, Ãâ€"zdemir C (2009). The morphological and anatomical properties of Lamium lycium (Lamiaceae), endemic to Turkey. Nord J Bot. 27: 388-396. BaÃ…Å ¸er KHC (1993). Essential oils of Anatolian Lamiaceae: A profile. Acta Hortic. 333: 217-238. Baytop T (1984). Tà ¼rkiye’de bitkiler ile tedavi. Ä °st. ÃÅ"niv. Yay. No: 3255, Istanbul. Baytop T (1999). Therapy with medicinal plants in Turkey, Past and Present. (2nd ed.) Nobel TÄ ±p Press. Ä °stanbul, Turkey. Ben Jannet H, Harzallah-Skhiri F, Mighri Z, Simmonds MSJ, Blaney WM (2000). Responses of Spo- doptera littoralis larvae to Tunisian plant extracts and to neo-clerodane diterpenoids isolated from Ajuga pseudoiva leaves. Fitoterapia. 71: 105-112. Chen H, Tan RX, Liu ZL, Zhang Y, Yang L (1996). Antibacterial neoclerodane diterpenoids from Ajuga lupulina. J. Nat. Prod. 59(7) 668-670. ÇelebioÄÅ ¸lu S, Baytop T (1949). A new reagent for microscopical investigation of plant, Publication of the Institute of Pharmacognosy, No. 10, 19: 3001, Ä °stanbul. ÇobanoÄÅ ¸lu D (1988). The morphological and cytological properties of Salvia palaestina Bentham (Lamiaceae). Turk. J. Bot. 12: 215-223. Davis PH (1982). Flora of Turkey and the Aegean Islands. Vol. 7. Edinburgh Univ. Press. Edinburg. Davis PH (1982-1988). Flora of Turkey and the east aegean islands, Vol 7, 10, Edinburg University Press. Dinà § M, Ãâ€"ztà ¼rk M (2008). Comparative morphological, anatomical and palynological studies on the genus Stachys L. sect. Ambleia Bentam (Lamiaceae) species in Turkey. Turk. J. Bot. 32: 113–121. Eric TJ, Michael VA, Linda WE (2007). The importance of petiole structure on inhabitability by ants in Piper sect. Macrostachys (Piperaceae). Bot. J. Linn. Soc. 153(2): 181-191. Heywood VH (1978). Flowering Plants of the World. Oxford, Oxford University Press. Kahraman A, Celep F, DoÄÅ ¸an M (2010). Anatomy, trichome morphology and palynology of Salvia chrysophylla Stapf (Lamiaceae). S. Afr. J. Bot. 76:187–195. Kandemir N (2003). The morphological, anatomical and karyological properties of endemic Salvia hypargeia Fich. mey. (Lamiaceae) in Turkey. Pak. J. Bot. 35: 219-236. Koyuncu O, YaylacÄ ± Ãâ€"K, Ãâ€"ztà ¼rk D (2010). Risk categories and ethnobotanical features of the Lamiaceae taxa growing naturally in Osmaneli (Bilecik/Turkey) and environs. Biodivers Conserv. 3(3): 31-45. Ãâ€"zdemir C, Ã…Å ¾enel G (2001). The morphological, anatomical and karyological properties of Salvia forskahlei L. (Lamiaceae) in Turkey. J Econ. Taxon. Bot. 19: 297-313. Ãâ€"zdemir C, Altan Y (2005). Morphological and anatomical investigations on endemic Scutellaria orientalis L. subsp. bicolor (Hochst) Edmund and subsp. santolinoides (Hausskn ex Bornm). Pak. J. Bot. 37(2): 213-226. Ãâ€"zkan M, Soy E (2007). Morphology, anatomy, hair and karyotype structure of Salvia blecharoclaena Hedge and Hub.-Mor. (Lamiaceae), endemic to Turkey. Pak. J. Biol. Sci. 10: 893-898. Metcalfe CR, Chalk L (1972). Anatomy of the dicotyledons, vol. II. Oxford University Press, Oxford. Navarro T, El Oualidi J (2000). Trichome morphology in Teucrium L. (Labiatae), a taxonomic review. Anales Jard. Bot. Madrid. 57:277–297. Sajjadi SE, Ghannadi A (2004). Volatile oil composition of the aerial parts of Ajuga orientalis L. from Iran. Z. Naturforsch. C. 59: 166-168. Shaheen AM (2007). Characteristics of the stem-leaf transitional zone in some species of Caesalpinioideae (Legumuninosae). Turk. J. Bot. 31: 297-310. Thorne RF (1992). Classification and geography of the flowering plants. Bot. Rev. 58: 225-348. Uysal Ä °, Ãâ€"ztà ¼rk M, Pirdal M (1991). Morphology, Anatomy and Ecology of Endemic Species of Sideritis trojana Bornm. Turk. J. Bot. 15: 371-379. Werker E, Ravid U, Putievsky E (1985). Structure of glandular hairs and identification of the main components of their secreted material in some species of the Labiatae. Israel J. Bot. 34: 31-45. 1 [a1]Should add faimly of this plant which is â€Å"Lamiaceae† [a2]Should add stem to be root, stem [a3]Remove â€Å"medicinal taxon† [a4]Should mention pith shape in the stem [a5]Better to be other world†detected† [a6]Should be â€Å"diastatic†

Police Strategies Essay

The topic I chose to research about is which police strategy/tactic is most effective in reducing crime and disorder. There are various forms of policing such as community-oriented policing, problem-oriented policing, hot spots policing, broken windows theory, and zero-tolerance policing. COP is a model of policing that stresses a two-way working relationship between the community and the police along with the police becoming more integrated into the local community, and citizens assuming an active role in crime control and prevention. POP is a concept created by Herman Goldstein in which he believes the police should take the categories of crime, order maintenance, and service and break them down into discrete problems and then develop specific responses to each one. Hot spots policing originated from research that revealed crime is extremely concentrated in small areas. The broken windows theory is about how crime problems develop at place, and how police should focus their role to stop crime problems from arising. According to Paul M.  Walters, there is a strategy for COP to prevent crime and disorder which is referred to as response to incidents (R2I). R2I requires law enforcement officers to react to crimes or emergency incidents. In order to promote citizen confidence in the police, officers should swiftly respond to any such incidents and establish and maintain control over the situation. R2I also requires officers to respond proactively to crime patterns. This is accomplished through such tactics as directed patrol, targeted identifications, etc. However, if police administrators do not carefully manage the R2I strategy, their departments can quickly be overwhelmed by community demands. In order to manage increased calls for police service, administrators need to monitor demand and then research as many creative ways as possible to respond to these calls. There are many ways to respond to calls for assistance that do not require the immediate dispatching of an officer in a patrol car. Other, less expensive responses may satisfy the request just as effectively. Another way to better serve jurisdictions using the R2I strategy is to invest in current technology in such areas as communications, information, case management and analysis, and transportation which may include automated mug systems, records management and retrieval systems, automated aging systems, and mobile data terminals. Department managers must then use all their resources, both technological and human, in a balanced way that produces not just activity but also results that they can measure against their mission statements. Managing the limited resources of departments to respond effectively to both incidents and calls for service, while producing the greatest advantage for their communities, requires managers to make informed, professional decisions. Foot patrol and Neighborhood Watch programs are two other popular strategies for the effectiveness of COP. A number of evaluations in the 1980s reported that while additional foot patrol did not reduce crime, it did increase feelings of safety. If people are less fearful they might not withdraw from the communities, and the process of neighborhood deterioration might not begin. Neighborhood Watch programs have repeatedly been found to have little impact on crime. Residents who live in areas with more crime, and who live in inner-city minority neighborhoods, have been less willing to participate in Neighborhood Watch programs or any other activities that involve partnership with the police. The effect of whether COP works is hard to say and evidence is very mixed. It’s hard to evaluate since it’s done differently from police department to police department. While a number of questions remain, the future of COP appears bright. According to Paul M.  Walters, the heart of the POP approach is the concept that police must be more responsive to the causes of crime, rather than merely dealing with the results of crime. Maintaining neighborhood safety can be more beneficial to the community than merely treating isolated neighborhood problems. This approach represents a significant shift in how both the public and the police view the role of law enforcement in the community. Problem-oriented policing is a proactive, decentralized approach to providing police services designed to reduce crime and disorder, and by extension, the fear of crime. Department heads achieve this by assigning officers to specific neighborhoods on a long-term basis. Long-term involvement between the officers and neighborhood residents fosters the development of credible relationships based on mutual trust and cooperation. It also allows a high-level exchange of information between citizens and police officers, as well as mutual input concerning policing priorities and tactics for specific areas of the community. Problem-oriented policing also istributes police services more effectively across the community and targets high-crime areas for problem-solving approaches that allow law enforcement to define and deal with the causes of crime. This helps to neutralize the undue influence of special interest groups that can be the recipients of preferred services when no system of community-based priorities exists. Systematic reviews and meta analysis are a method for determining whether POP reduces crime and disorder. A study was conducted by Weisburg, Telep, Hinkle, and Eck. Whether they used a more conservative mean effect size approach or examined the largest effects on crime and disorder reported, they found that POP approaches have a statistically significant effect on the outcomes examined. Importantly, the results are similar whether we look at experimental or nonexperimental studies. The small group of studies in the review allows us to come to a solid conclusion regarding the promise of POP, but it does not allow statistical conclusions regarding the types of approaches that work best for specific types of problems. They think it a major public policy failure that the government and the police have not invested greater effort and resources in identifying the POP approaches and tactics that work best to combat specific types of crime. Moreover, a much larger number of studies are needed to draw strong generalizations regarding the possible effectiveness of POP across different types of jurisdictions and different types of police agencies. The portfolio of available studies does not allow us to draw conclusions about such contextual factors and suggests that U.  S. policing has adopted POP widely without an evidence base for deciding where and when it should be used. The central conclusion of our review is that POP as an approach has significant promise to ameliorate crime and disorder problems broadly defined. Hot spots policing is easier to implement than COP and POP. Research early on showed it had promise in reducing crime. It’s easy to implement as officers are still doing patrol and making arrests. Computerized crime mapping is used in nearly every police department that does hot spots policing. Some programs can do statistical analyses to identify hot spots and find trends in crime across time and space. The programs also can have maps updated with the latest data each day. Studies have found that hot spots policing is at least moderately effective in reducing crime. It’s so hard to know what exactly works because many studies also involve elements of POP and other tactics. The broken windows theory is widely viewed as effective in policing circles after it was used in New York City in the 1990s and the city had a large crime drop. There are several suggestions for how police could best prevent crime with the broken windows theory. Police should return to the order maintenance role. Police should not ignore disorder. Police should negotiate consensus with residents and users of public spaces about what is or is not acceptable in that area. The key is to deal with disorder quickly and not let it untended, and clean it up in areas that have declined. This is hypothesized to prevent fear of crime and maintain social controls in areas such as residents aren’t afraid to intervene and/or move away from the area. Some studies have found increased complaints against the police with the broken windows theory. In conclusion, the research I obtained about the various police strategies and tactics leads to an important statement. Unfortunately, there is no clear answer. There is fairly mixed and weak research evidence about the impacts of these tactics on crime. COP seems effective in fighting fear of crime and improving police-community relations but not in fighting crime. A report by the National Academy reinforces that the most effective strategies and tactics are those that target small locations, take a focused approach, and are highly proactive.

Cryogenics Definition and Uses

Cryogenics is defined as the scientific study of materials and their behavior at extremely low temperatures. The word comes from the Greek cryo, which means cold, and genic, which means producing. The term is usually encountered in the context of physics, materials science, and  medicine. A scientists who studies cryogenics is called a cryogenicist. A cryogenic material may be termed a cryogen. Although cold temperatures may be reported using any temperature scale, the Kelvin and Rankine scales are most common because they are absolute scales that have positive numbers. Exactly how cold a substance has to be to be considered cryogenic is a matter of some debate by the scientific community. The U.S. National Institute of Standards and Technology (NIST) considers cryogenics to include temperatures below  Ã¢Ë†â€™180  °C (93.15 K; −292.00  °F), which is a temperature above which common refrigerants (e.g., hydrogen sulfide, freon) are gases and below which permanent gases (e.g., air, nitrogen, oxygen, neon, hydrogen, helium) are liquids. There is also a field of study called high temperature cryogenics, which involves temperatures above the boiling point of liquid nitrogen at ordinary pressure (−195.79  °C (77.36 K; −320.42  °F), up to −50  °C (223.15 K; −58.00  °F). Measuring the temperature of cryogens requires special sensors. Resistance temperature detectors (RTDs) are used to take temperature measurements as low as 30 K. Below 30 K, silicon diodes are often used. Cryogenic particle detectors are sensors that operate a few degrees above absolute zero and are used to detect photons and elementary particles. Cryogenic liquids are typically stored in devices called Dewar flasks. These are double-walled containers that have a vacuum between the walls for insulation. Dewar flasks intended for use with extremely cold liquids (e.g., liquid helium) have an additional insulating container filled with liquid nitrogen. Dewar flasks are named for their inventor, James Dewar. The flasks allow gas to escape the container to prevent pressure buildup from boiling that could lead to an explosion. Cryogenic Fluids The following fluids are most often used in cryogenics: Fluid Boiling Point (K) Helium-3 3.19 Helium-4 4.214 Hydrogen 20.27 Neon 27.09 Nitrogen 77.36 Air 78.8 Fluorine 85.24 Argon 87.24 Oxygen 90.18 Methane 111.7 Uses of Cryogenics There are several applications of cryogenics. It is used to produce cryogenic fuels for rockets, including liquid hydrogen and liquid oxygen (LOX). The strong electromagnetic fields needed for nuclear magnetic resonance (NMR) are usually produced by supercooling electromagnets with cryogens. Magnetic resonance imaging (MRI) is an application of NMR that uses liquid helium. Infrared cameras frequently require cryogenic cooling. Cryogenic freezing of food is used to transport or store large quantities of food. Liquid nitrogen is used to produce fog for special effects and even specialty cocktails and food. Freezing materials using cryogens can make them brittle enough to be broken into small pieces for recycling. Cryogenic temperatures are used to store tissue and blood specimens and to preserve experimental samples. Cryogenic cooling of superconductors may be used to increase electric power transmission for big cities. Cryogenic processing is used as part of some alloy treatments and to facilitate low temperature chemical reactions (e.g., to make statin drugs). Cryomilling is used to mill materials that may be too soft or elastic to be milled at ordinary temperatures. Cooling of molecules (down to hundreds of nano Kelvins) may be used to form exotic states of matter. The Cold Atom Laboratory (CAL) is an instrument designed for use in microgravity to form Bose Einstein condensates (around 1 pico Kelvin temperature) and test laws of quantum mechanics and other physics principles. Cryogenic Disciplines Cryogenics is a broad field that encompasses several disciplines, including: Cryonics - Cryonics is the cryopreservation of animals and humans with the goal of reviving them in the future. Cryosurgery - This is a branch of surgery in which cryogenic temperatures are used to kill unwanted or malignant tissues, such as cancer cells or moles. Cryoelectronics - This is the study of superconductivity, variable-range hopping, and other electronic phenomena at low temperature. The practical application of cryoelectronics is called cryotronics. Cryobiology - This is the study of the effects of low temperatures on organisms, including the preservation of organisms, tissue, and genetic material using cryopreservation. Cryogenics Fun Fact While cryogenics usually involves temperature below the freezing point of liquid nitrogen yet above that of absolute zero, researchers have achieved temperatures below absolute zero (so-called negative Kelvin temperatures). In 2013 Ulrich Schneider at the University of Munich (Germany) cooled gas below absolute zero, which reportedly made it hotter instead of colder! Sources Braun, S., Ronzheimer, J. P., Schreiber, M., Hodgman, S. S., Rom, T., Bloch, I., Schneider, U. (2013) Negative Absolute Temperature for Motional Degrees of Freedom.  Science  339,  52–55.Gantz, Carroll (2015). Refrigeration: A History. Jefferson, North Carolina: McFarland Company, Inc. p. 227. ISBN 978-0-7864-7687-9.  Nash, J. M.  (1991) Vortex Expansion Devices for High Temperature Cryogenics. Proc. of the 26th Intersociety Energy Conversion Engineering Conference, Vol. 4, pp. 521–525.

Annotated Bibliography Issue of IT Ethics - 2194 Words

Annotated Bibliography Over the last several years, the issue of IT ethics has been increasingly brought to the forefront. This is because of transformations occurring through rapid advancements and the way various applications are utilized. To fully understand what is taking place requires conducting an annotated bibliography on the subject and the impact it is having on these standards. These findings will highlight the overall scope of the challenges and the long term effects they are having on stakeholders. Spinello, R. A. (2011). Cyber Ethics - Morality and Law in Cyberspace. Sudbury, MA: Jones and Bartlett Learning. In chapters 5 and 6; Spinello (2011) found that privacy is becoming a major challenge for all different segments of society. This is occurring in a number of different areas including: consumer spending / buying patterns, inside the home / workplace and the way this technology is applied. Moreover, there is a discussion about the various vulnerabilities of the Internet and how issues such cybercrime / spying have resulted directly from these increases. (Spinello, 2011) To address these challenges, both the US and the EU have adopted various laws governing how data is collected and utilized. At the same time, the industry has been focused on improving the ability to encrypt data in order to protect the privacy of individuals. This is helping to establish a form of ethics as new standards. That is utilized in the process of maintaining these guidelines.Show MoreRelatedAcademic Research Reflection1203 Words   |  5 PagesReflection Paper One of the most important aspects of conducting a research project is maintaining the ethics of academic research and producing a paper that is free of plagiarism. For a researcher to complete his or her study, it requires referencing the work of others who have analyzed the variable of the topic previously. This gives insight into the problem and makes the research paper more concrete and thus provides more depth to the analysis. Hence, several universities and accredited academicRead MoreA Annotated Bibliography On The Field Of Nursing1600 Words   |  7 PagesAn annotated bibliography is used to assess other written works of information related to the topic you are discussing. This assignment is to help students learn how to deal with one of the many communication concerns they may come across in the field of nursing. They will achieve this by researching and assessing other sources as well as evidently and logically writing about their findings. The topic of this annotated bibliography is communicating with people who have Aphasia. 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II Professor Kamm Monday amp; Wednesday 7PM – 8:15PM Annotated Bibliography amp; Essay Annotated Bibliography on Global Warming: Fact or Fiction Fumento, Michael. â€Å"The Cooling Off on Global Warming.† The Washington Times 8 July 1999: 15. LexisNexis Academic . Academic Universe. W. I. Dykes Lib., University of Houston-Downtown. 20 Feb. 2010 http://www.lexisnexis.com.ezproxy.uhd.edu/hottopics/lnacademic/ Fumento explains that a nonprofit group