Examination of Tectonic Activity Based on Knickpoint Distribution and Movement Potential of Faults in Khuzestan Province, South West Zagros, Iran

Although the distribution of fluvial knickzones, as an important geomorphic feature in bedrock river morphology, has been studied by many investigators, the role of them in examination of tectonic activity has not been well investigated, specially based on its comparision with movement potential faults over a broad area. This study examines the tectonic activity of Khuzestan province, South West Zagros, by considering two different parameters: distribution of the fluvial knickzones along Mountain Rivers and evaluation of faults activity in the study area. A segment of a river long-profile that is steeper than adjacent segments is commonly referred to as a knickzone or a knickpoint if it is visibly steeper than the trend of the longitudinal profile. 

Knickzones are often observed along bedrock rivers and the most visible form is a waterfall. Knickzones are supposed to be a response to base-level changes or to alternations of local lithology. Upstream migration of knickzones has been argued to cause rapid river incision and result in the formation of terraces and instability of valley-side slopes. Knickpoint evolution on a river can provide evidence for uplift of plate margins. Knickpoints can be used as geomorphic markers in steep, rapidly eroding landscapes that commonly lack datable river terraces.

A Study on the Zoogeography of Indian Penaeidae

Shrimps and Prawns of various kinds have certainly been a source of protein for human consumptions from very early times. Within historical times reference is made to prawn in ancient Chinese and Japanese literature. Usage of the term ‘Prawn’ and ‘Shrimp’ are somewhat confusing. In some western literature the term ‘Shrimp’ is applied for Penaeoidea and Sergestoidea, but in the east these are called ‘Prawn’. Holthuis discussed the contradiction but did not arrive at any conclusion. In the Prawn Symposium ofthe Indo-Pacific Fisheries Council held at Tokyo in 1955 it was decided thatthe word ‘Prawn’ should be applied to the Penaeids, Pandalids and Palemonids while ‘Shrimp’ to the smaller species belonging to the other families. As such in the present study the term ‘Prawn’ is used for all the species belonging to family Penaeidae. 

Among a variety of edible decapod crustaceans, prawns contribute largely to the fishery wealth of many nations. Exploitation of prawnresource from the seas around each country is playing increasingly significantrole in furthering their national economy. In recent years, in spite of some ecological hazards, the demand for prawns and prawn products has increased so much that every country is making efforts to utilize hitherto unknown but usable stocks and expansion of prawn fisheries and industries near coast line is rightly being given the maximum encouragement in the development programme of each nation. Therefore, the distribution of different species gradually extending their range of distribution and newer species were recorded throughout coastal region of each nation.

Sex versus Gender in Sea Urchins and Leeches Two Centuries after Lamarck 1816

No other words arouse more interest and excitement than “sex” and “gender”. However, clear, concise definitions of these terms sensu stricto are elusive, despite the fact that Carolus Linnaeus (1707-1778) published, in 1753, a “Sexual system” of plant systematics (with reference to gender issues in humans) that was later abandoned by botanists. Recently, theterm “sex” (in humans) was used with reference to organs, chromosomalcomplements and hormones related to reproduction. In contrast, “gender” was defined as “cultural attitudes that shape ‘feminine’ and ‘masculine’ behaviors that are learned and vary by culture, historical era, and ethnicity”. 

In addition, in animal research, the “g-word” is used to indicate the attitude of investigators with respect to the handling of male or female laboratory animals. Here, I analyze the original “Linnaean” meaning of“sex” within the context of bi-parental reproduction, with reference to Lamarck’s (1816) description of a marine model organism that has later been used to elucidate this process at the sub-cellular level. In addition, Charles Darwin’s (1809-1882) concept of different gender roles in sexually reproducing groups of males/females and hermaphroditic animals is addressed.