Economy and subsistence in the Early Neolithic site of Carrascal (Oeiras, Portugal)

Early Neolithic settlements in southwestern Iberia are rare and, so far, only a few faunal assemblages, mostly from Portuguese Estremadura, have been analysed. The zooarchae- ological studies suggest that animal husbandry was introduced to the area by Neolithic marine settlers originating from the Mediterranean and that domesticated animal herding, particularly sheep, was of outmost importance to the human communities. Located in lower Estremadura, Carrascal is an open-air site, featuring several dwelling structures, a diversified set of artefacts, and a well-established chronology for its Early Neolithic occupation (cal BC). It also yielded a faunal assemblage of considerable size and variability, which includes vertebrates (mammals and fishes) and invertebrates (molluscs). The present study, which focuses on the vertebrate materials, shows that during Early Neolithic the community that inhabited Carrascal practiced a diversified set of subsistence activities in which animal husbandry was prevalent. There is an abundance of caprines (mainly sheep) and swine, followed by cattle. The age at death data suggests a mixed animal exploitation system, with swine being mostly killed at a younger age (presumably for meat), while cattle was slaughtered after reaching adulthood (perhaps for milk production) and caprines show a mixed pattern. This study also reinforces the idea that, for the Neolithic communities living in lower Estremadura, hunting was a less prevailing activity (au- rochs and, perhaps, wild boar were identified, but red deer is absent in Carrascal) when compared with the human groups that lived in the central Estremadura Limestone Massif, a situation that may be due to different ecosystems and human demography.

Respons fisiologi dan hasil lateks tanaman karet klon GT 1 di kebun karet rakyat terhadap sistem eksploitasi dan curah hujan

AbstrakKlon GT 1 adalah klon Slow Starter (SS) dimana perubahan sukrosa menjadi partikel karet di dalam pembuluh lateks berlangsung lambat dan pada saat gugur daun hasil lateks lebih stabil. Penelitian ini bertujuan untuk mengetahui hubungan curah hujan dan sistem eksploitasi terhadap fisiologi dan hasil lateks klon GT1. Penelitian dilaksanakan di Kabupaten Langkat Kecamatan Besitang Sumatera Utara, ketinggian tempat 500 – 700 m di atas permukaan laut. Analisa fisiologi lateks di PT. Sucofindo Indonesia. Tanaman yang digunakan adalah klon GT 1 umur 25 tahun dengan besar lilit batang antara 60 – 75 cm, diukur dengan ketinggian 130 cm dari permukaan tanah. Metode percobaan menggunakan Rancangan Split Plot. Petak utama adalah panjang alur sadap, terdiri dari tiga taraf, yaitu panjang alur sadap 1/4 spiral, panjang alur sadap 1/2 spiral, dan panjang alur sadap 1/8 spiral. Anak petak adalah aplikasi stimulan, terdiri dari dua taraf, yaitu stimulan cair dan stimulan gas. Semua perlakuan diulang tiga kali. Hasil penelitian menunjukkan bahwa panjang alur sadap pendek dan aplikasi stimulan cair memiliki kadar sukrosa lateks tinggi . Aplikasi stimulan gas menunjukkan kadar sukrosa lateks yang tinggi pada panjang alur sadap panjang. Kadar tiol belum menunjukkan tingkat stress pada klon GT 1 dapat terlihat dari kadar tiolnya berkisar 0,84 – 1,10 mM. Produksi lateks klon GT 1 lebih dipengaruhi oleh sistem ekploitasi daripada curah hujan.Kata Kunci: fisiologi lateks, Hevea brasiliensis, klon GT 1, slow starterAbstractGT 1 is a Slow Starter (SS) clone where the change of sucrose into rubber particles in the latex vessels is slow, and at the time of leaves fall, the latex yield is more stable. This study aimed to determine the relationship between agro-climate and exploitation system on the physiology and yield of latex clone GT1. The research was carried out in Langkat, Besitang, North Sumatra, at an altitude of 500 – 700 m above sea level. Physiological traits analysis of latex was conducted at PT. Sucofindo Indonesia. The plant used was a 25 years old GT 1 clone with a trunk circumference of 60 – 75 cm, measured at the height of 130 cm from the ground. The research method used Split Plot. The main plot was length of tapping path, consisted of 1/4, 1/2, and 1/8 spiral tapping groove length. The subplot was stimulant application, consisted of liquid and gas stimulant. The results showed that short tapping groove length and liquid stimulant application had high latex sucrose content, as given by long tapping groove length and gas stimulant application. Thiol level did not show the stress level in the GT 1 clone, it could be seen from the thiol level of 0.84 – 1.10 mM. Latex production of GT 1 clones was more influenced by the exploitation system than by rainfall.Keywords: GT 1 clone, Hevea brasiliensis, latex phyisiology, slow starter

An Explanation of Energy Return on Investment From an Entropy Perspective

Low-carbon energy transformation is a major trend in world energy development, and measures to mitigate carbon emissions can vary substantially in terms of the energy they require. A common method of evaluating energy use in energy resource exploitation is energy return on investment (EROI). One of the criticisms of EROI concerns uncertainty regarding the input and output factors for the calculation. To make the issue clear, we interpret EROI in terms of entropy, which is the most basic concept in physics. We consider an energy resource exploitation system to be a kind of dissipative structure and construct a basic entropy analysis framework for an energy resource exploitation system. We then derive the relationship between EROI and entropy change. The theory of EROI is consistent with the basic requirement for a dissipative structure, which is that the total entropy change must be negative. EROI is a method of using entropy theory to evaluate energy resource exploitation. It is inappropriate and unnecessary to quantify all factors as energy units as the input and output factors are multidimensional while energy is a one-dimensional standard. Future development of the EROI method should be guided by entropy theory. A series of EROI related indicators will increase its application and policy significance.

THE QUANTIFICATION METHOD OF FUNCTIONAL AVAILABILITY MILITARY VEHICLES

The availability is one of the most important feature of a technical object which shapes its operational quality. The paper undertakes the issue related to the quantification of functional availability of vehicles, with reference to reliability aspects. The conducted exploitation research paved the way for elaborating methods of determining functional availability for vehicles, in particular focusing on reliability. The essential research was conducted using the developed mathematical model based on the probabilistic, stochastic Markov process, which allowed modelling the process of changes in the exploitation states of vehicles. In view of the above, it is essential to develop methods that enable the most accurate estimation of the functional availability of vehicles. Knowing the values of functional availability, we can estimate the probability of performing assigned tasks and precisely control the vehicle exploitation system, especially in terms of availability, which is important for vehicles. This work presents a method for determining the functional availability of vehicles, taking into account the limitations introduced by the vehicle exploitation system. Particular attention was paid to the possibility of using probabilistic, stochastic semiMarkov models, whose rules and method of creation were generally described, with regard to the ability to acquire operational data in the vehicle exploitation system.

Perceived extension needs of rubber production among farmers in Delta State, Nigeria

The need to develop a sustainable exploitation system for the Nigerian rubber farmers requires that extension services should be available to assist the farmers in specific areas that can help them function effectively and improve productivity. The study investigated the perceived extension needs of rubber production farmers in Delta state Nigeria. The specific objectives of the study were to determine sources of information on rubber production, varieties of rubber clones cultivated by the respondents, perceived extension needs of rubber farmers, and constraints to rubber production. A multi stage sampling technique was used to select 120 rubber farmers as respondents for the study. Data were analysed using frequency, percentages, means and Pearson Product Moment correlation analysis. Results showed that majority of the respondents (85.5%) were male, married (83.3%) and had average farming experience of 14 years. The NIG801 and NIG800 varieties were the local clones majorly cultivated and the GT1 and PB217 varieties were the exotic clones majorly cultivated. Findings also showed that respondents need production information on use of formic acid for latex coagulation (66.7%), use of ammonia for latex preservation (73.3%) and marketing information (60.8%). The constraintsindicated by the respondents were problem of land tenure (81.7%), lack of adequate credit facilities (70%), fire outbreaks (72.5%) among others. The result of the hypothesis showed that age (r = 0.199) had a positive significant relationship with farmers’ extension needs. It was recommended that extension personnel should be trained on techniques of rubber production in order to deliver effectively to the farmers. Key words: extension needs, rubber, farmers, Delta, Nigeria

Functional structure of battery drive for self-propelled mining rig used in room-pillar ore exploitation system

The article presents the structure of the battery drive of a self-propelled mining vehicle on the example of a drilling rig, used in the room-pillar system of copper ore exploitation. Such solutions, due to the ore mining in increasingly difficult operating conditions, are becoming more and more popular in the world. The main assumptions required for the synthesis of this type of drive were indicated, as well as the adopted structure of such a solution was described. The selection of the appropriate drive structure determines the final work characteristics of the self-propelled mining vehicle, and thus the actual suitability of such a machine for use in mining conditions. The paper also details the main technological advantages of this type of drive over classic internal combustion drives.

An Analysis of Reliability of Military Vehicles

The paper describes issues related to reliability of military vehicles based on recorded operational events. Seeking the quantification of reliability for exploiting vehicles in military units, an extensive analysis of factors shaping the reliability level was made, taking into consideration all phases of military vehicles existence and a peculiar character of the exploitation process of military vehicles. The importance of reliability research in the decision process optimization was emphasized, controlling the efficiency and availability of the exploitation system.